JP7338085B2 - optical laminate - Google Patents

Description

TECHNICAL FIELD The present invention relates to an optical laminate suitable for encapsulating light-emitting elements of self-luminous display devices such as mini/micro LEDs.

In recent years, self-luminous display devices typified by mini/micro LED display devices (Mini/Micro Light Emitting Diode Displays) have been devised as next-generation display devices. A mini/micro LED display device has, as a basic configuration, a substrate on which a large number of minute LED light emitting elements (LED chips) are arranged at high density is used as a display panel, and the LED chips are sealed with a sealing material, A cover member such as a resin film or a glass plate is laminated on the outermost layer.

Self-luminous display devices such as mini/micro LED display devices have several methods such as a white backlight method, a white light emission color filter method, and an RGB method. In some cases, a black sealing material is used to prevent reflection of metal wiring and metal oxides such as ITO arranged on the substrate (see, for example, Patent Documents 1 to 3). In particular, in an RGB type mini/micro LED display device in which LED chips are arranged, the black encapsulating material can contribute to prevention of RGB color mixing and improvement of contrast.

JP 2019-204905 A Japanese Patent Application Laid-Open No. 2017-203810 Japanese Patent Publication No. 2018-523854

When the black encapsulant is used, the upper part (image display side) of a light emitting element such as an LED chip is covered with a black encapsulant having a reduced transmittance for visible light, resulting in a lower luminous efficiency and a darker image. There is a problem of becoming In order to deal with this, there is also a problem that power consumption increases when the output of the LED chip is increased to increase the emission luminance.

If the visible light transmittance of the black encapsulant is increased in order to increase the luminous efficiency, there is a trade-off between the antireflection function of the metal wiring and the like, the prevention of RGB color mixing, and the decrease in contrast. Reconciliation was a difficult problem to solve.

On the other hand, as the black sealing material, a liquid curable resin containing a black colorant (dye or pigment) or an adhesive is used. When using a liquid curable resin containing a black colorant, there is a problem that unevenness in blackness occurs due to unevenness in thickness. In addition, pigments are often selected because they are superior in both heat resistance and weather resistance compared to dyes. Problems such as uneven filling during resin filling and uneven dispersion of pigment during flow also occur. In addition, since the surface of the liquid curable resin that hardens after sealing does not have adhesive strength, it is necessary to laminate the cover member using an adhesive or the like, and there is the problem that additional man-hours and members are required. there were.

The present invention was conceived under the circumstances as described above, and an object of the present invention is to provide a mini/micro LED having an antireflection function such as a metal wiring and an improved contrast while increasing the luminous efficiency. An object of the present invention is to provide an optical laminate suitable for manufacturing a self-luminous display device such as a display device.
Another object of the present invention is to reduce the number of steps and necessary members in the manufacturing process of the above self-luminous display device.

The inventors of the present invention have made intensive studies to achieve the above object, and found that an optical laminate obtained by laminating two pressure-sensitive adhesive layers with different transmittances and then laminating a base material is used for manufacturing a self-luminous display device. By doing so, it was found that a self-luminous display device having improved luminous efficiency, an antireflection function of metal wiring and the like, and an improved contrast can be manufactured. In addition, by using the optical layered body, it is possible to reduce the number of processes and the required members, and it is possible to efficiently produce a self-luminous display device with improved luminous efficiency, anti-reflection function such as metal wiring, and contrast. I found that it can be manufactured. The present invention has been completed based on these findings.

That is, the first aspect of the present invention has a laminated structure in which a first adhesive layer, a second adhesive layer, and a base material are laminated in this order, and the first adhesive layer is visible The light transmittance T ₁ and the visible light transmittance T ₂ of the second pressure-sensitive adhesive layer provide an optical laminate that satisfies T ₁ <T ₂ .

In the optical laminate according to the first aspect of the present invention, the visible light transmittance T ₁ of the first pressure-sensitive adhesive layer and the visible light transmittance T ₂ of the second pressure-sensitive adhesive layer satisfy T ₁ <T ₂ That is, the configuration in which the visible light transmittance of the first pressure-sensitive adhesive layer is lower than the visible light transmittance of the second pressure-sensitive adhesive layer makes the optical laminate according to the first aspect of the present invention self-luminous. When used in the manufacture of a display device, the first pressure-sensitive adhesive layer is preferable for preventing reflection from metal wiring on the display panel, preventing color mixture between the arranged light-emitting elements, and improving contrast. In this configuration, the second pressure-sensitive adhesive layer having a higher visible light transmittance than the first pressure-sensitive adhesive layer is positioned above the light-emitting element (on the image display side), thereby improving luminous efficiency. This is preferable in that the image can be made brighter by increasing the brightness of the emitted light, and the power consumption can be reduced by increasing the output for increasing the luminance of the emitted light.
That is, the optical layered body according to the first aspect of the present invention has such a structure that the luminous efficiency is improved, and at the same time, the antireflection function such as the metal wiring, which is in a trade-off relationship, and the mixed color of RGB It also solves the problems of prevention and improvement of contrast.

Further, by using the optical laminate of the first aspect of the present invention for manufacturing a self-luminous display device, the laminated structure of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer can be arranged on the display panel. It becomes a sealing material that seals the light emitting element, and the base material becomes the cover member of the outermost layer, so there is no need to laminate a separate cover member after sealing, and the number of processes and necessary members can be reduced. Improve efficiency.

Furthermore, the configuration in which the sealing material for sealing the light-emitting element is an adhesive layer composed of a laminated structure of the first adhesive layer and the second adhesive layer is useful in manufacturing a self-luminous display device. When the device is sealed with the pressure-sensitive adhesive layer, unevenness in blackness due to unevenness in thickness, unevenness in filling, unevenness in pigment dispersion, etc. described above is unlikely to occur. can be improved.

In the optical layered body of the first aspect of the present invention, the visible light transmittance T ₁ of the first adhesive layer and the visible light transmittance T ₃ of the substrate preferably satisfy T ₁ <T ₃ . . This configuration is preferable in that the luminous efficiency described above can be improved.

In the optical layered body of the first aspect of the present invention, the visible light transmittance T ₁ of the first pressure-sensitive adhesive layer is preferably 80% or less. This configuration is preferable in terms of the antireflection function of the metal wiring and the like, prevention of color mixture of RGB, and further improvement of contrast. Also, the visible light transmittance T ₂ of the second adhesive layer is preferably 85 to 100%. This configuration is preferable in terms of further improving the luminous efficiency described above. That is, the visible light transmittance T ₁ of the first adhesive layer is 80% or less, and the visible light transmittance T ₂ of the second adhesive layer is 85 to 100%. This is extremely suitable for making it possible to achieve both the antireflection function of the metal wiring and the like, the prevention of RGB color mixing, and the improvement of the contrast, which are in a trade-off relationship, while improving the contrast.

In the optical layered product of the first aspect of the present invention, the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are a pressure-sensitive adhesive composition having a composition selected from a photocurable pressure-sensitive adhesive composition and a solvent-based pressure-sensitive adhesive composition. It is preferably a pressure-sensitive adhesive layer formed from a material. The pressure-sensitive adhesive composition forming the first pressure-sensitive adhesive layer preferably contains a colorant. These configurations are configured so that T ₁ and T ₂ satisfy T ₁ <T ₂ , and further improve the luminous efficiency, the antireflection function of metal wiring, etc., the prevention of RGB color mixing, and the contrast. , is preferred.

In the optical layered body of the first aspect of the present invention, the pressure-sensitive adhesive composition preferably contains an acrylic polymer. The acrylic polymer preferably contains a (meth)acrylic block copolymer. The pressure-sensitive adhesive composition forming the first pressure-sensitive adhesive layer is preferably a solvent-based pressure-sensitive adhesive composition containing a (meth)acrylic block copolymer. These configurations are effective when using the optical layered body of the first aspect of the present invention for manufacturing a self-luminous display device. ) is preferable because it fills the steps of the light-emitting elements arranged on the display panel without gaps, and is excellent in step absorption and workability.

In the optical laminate according to the first aspect of the present invention, the thickness of the first adhesive layer is preferably 10-300 μm, more preferably 15-200 μm. The thickness of the second adhesive layer is preferably 1 to 500 μm, more preferably 10 to 300 μm, even more preferably 15 to 200 μm. The ratio of the thickness of the second pressure-sensitive adhesive layer to the thickness of the first pressure-sensitive adhesive layer (thickness of the second pressure-sensitive adhesive layer/thickness of the first pressure-sensitive adhesive layer) is preferably 1.0 to 5.0. , more preferably 1.2 to 4.0, more preferably 1.3 to 3.0. In these configurations, the first pressure-sensitive adhesive layer sufficiently seals between the light emitting elements arranged on the display panel of the self-luminous display device, thereby preventing reflection of metal wiring and the like and preventing color mixture of RGB. It is preferable in that the light emitting efficiency can be improved by covering the upper portion (on the image display side) of the light emitting element with the second pressure-sensitive adhesive layer having high transparency.

In the optical layered body of the first aspect of the present invention, it is preferable that the surface of the substrate on which the second pressure-sensitive adhesive layer is not laminated is subjected to antireflection treatment and/or antiglare treatment. The antireflection treatment and/or antiglare treatment is preferably an antiglare layer provided on one side of the substrate. The anti-glare layer is formed using an anti-glare layer-forming material containing a resin, particles, and a thixotropy-imparting agent, and the anti-glare layer is formed on the surface of the anti-glare layer by aggregation of the particles and the thixotropy-imparting agent. It is preferable to have agglomerates that form convexities. The average inclination angle θa (°) of the projections on the surface of the antiglare layer is preferably in the range of 0.1 to 5.0. These configurations impart an antireflection function and/or an antiglare function to the surface of the optical layered body of the first aspect of the present invention, and prevent deterioration of visibility due to reflection of external light, reflection of images, etc. It is preferable from the viewpoint of adjusting appearance such as glossiness.

In the optical laminate according to the first aspect of the present invention, a surface protection film may be further laminated on the surface of the substrate on which the second pressure-sensitive adhesive layer is not laminated. Such a configuration is suitable for preventing the adhesion of scratches and dirt during the manufacture, transportation, and shipment of the optical layered body and optical products including the same.

A second aspect of the present invention is a self-luminous display device including a display panel in which a plurality of light emitting elements are arranged on one side of a substrate, and the optical laminate of the first aspect of the present invention, wherein Provided is a self-luminous display device in which the surface of the display panel on which the light emitting elements are arranged and the first pressure-sensitive adhesive layer of the optical laminate are laminated. In the self-luminous display device according to the second aspect of the present invention, the display panel may be an LED panel in which a plurality of LED chips are arranged on one side of a substrate. Such a configuration is preferable in that the self-luminous display device of the second aspect of the present invention can improve luminous efficiency, prevent reflection of metal wiring on the substrate, prevent mixture of RGB colors, and improve contrast.

By using the optical layered body of the present invention for manufacturing a self-luminous display device, it is possible to efficiently manufacture a self-luminous display device with improved luminous efficiency, antireflection function of metal wiring and the like, and contrast.

FIG. 1 is a schematic diagram (cross-sectional view) showing one embodiment of the optical layered body of the present invention. FIG. 2 is a schematic diagram (cross-sectional view) showing another embodiment of the optical layered body of the present invention. FIG. 3 is a schematic diagram (cross-sectional view) showing another embodiment of the optical layered body of the present invention. FIG. 4 is a schematic diagram (sectional view) showing an embodiment of the self-luminous display device (mini/micro LED display device) of the present invention. FIG. 5 is a schematic diagram (sectional view) showing another embodiment of the self-luminous display device (mini/micro LED display device) of the present invention. FIG. 6 is a schematic diagram (sectional view) showing another embodiment of the self-luminous display device (mini/micro LED display device) of the present invention.

A first aspect of the present invention provides an optical laminate. The optical laminate of the first aspect of the present invention has a laminated structure in which a first adhesive layer, a second adhesive layer, and a substrate are laminated in this order. The visible light transmittance T ₁ of the first pressure-sensitive adhesive layer and the visible light transmittance T ₂ of the second pressure-sensitive adhesive layer satisfy T ₁ <T ₂ .

The term “optical” in the optical laminate of the first aspect of the present invention means that it is used for optical purposes, and more specifically, it is used for manufacturing products (optical products) using optical members. means to be Examples of optical products include image display devices and input devices such as touch panels. Self-luminous display devices such as mini/micro LED display devices and organic EL (electroluminescence) display devices are preferred. / Can be suitably used in the manufacture of micro LED display devices.

Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto and is merely an example.
1 to 3 are schematic diagrams (cross-sectional diagrams) showing one embodiment of the optical laminate according to the first aspect of the present invention. 4 to 6 are schematic views (cross-sectional views) showing one embodiment of the self-luminous display device (mini/micro LED display device) according to the second aspect of the present invention.

In FIG. 1, the optical laminate 10 has a laminate structure in which a first adhesive layer 1, a second adhesive layer 2, and a substrate 3 are laminated in this order. In FIG. 2, the optical laminate 11 is subjected to antireflection treatment and/or antiglare treatment 4 on the surface 3a of the substrate 3 on which the second pressure-sensitive adhesive layer 2 is not laminated. In FIG. 3, the optical layered body 12 has an antiglare layer 4a formed as antireflection treatment and/or antiglare treatment on the surface 3a of the substrate 3 on which the second pressure-sensitive adhesive layer 2 is not laminated.
In this embodiment, the visible light transmittance T ₁ of the first adhesive layer 1 and the visible light transmittance T ₂ of the second adhesive layer 2 satisfy T ₁ <T ₂ . That is, the visible light transmittance of the first adhesive layer 1 is lower than the visible light transmittance of the second adhesive layer 2 .

In FIG. 4, a self-luminous display device (mini/micro LED display device) 20 includes a display panel in which a plurality of LEDs 7 are arranged on one side of a substrate 5, and an optical laminate 10 according to the first aspect of the present invention. . The surface of the display panel on which the LED chips 7 are arranged and the first adhesive layer 1 of the optical laminate 10 are laminated. In FIG. 5, a self-luminous display device (mini/micro LED display device) 21 is provided with an antireflection treatment and/or an antiglare treatment 4 on the surface 3a of the substrate 3 on which the second adhesive layer 2 is not laminated. It is In FIG. 6, the self-luminous display device (mini/micro LED display device) 22 has an antiglare layer as antireflection treatment and/or antiglare treatment on the surface 3a on which the second adhesive layer 2 of the base material 3 is not laminated. 4a is formed.

In this embodiment, a metal wiring layer 6 for sending light emission control signals to each LED chip 7 is laminated on the substrate 5 of the display panel. LED chips 7 that emit red (R), green (G), and blue (B) lights are alternately arranged on a substrate 5 of the display panel via metal wiring layers 6 . The metal wiring layer 6 is made of metal such as copper, and reflects the light emitted from each LED chip 7 to reduce the visibility of the image. In addition, the lights emitted from the LED chips 7 of each color of RGB are mixed, and the contrast is lowered.

In this embodiment, each LED chip 7 arranged on the display panel is sealed with the first pressure-sensitive adhesive layer 1 and the second pressure-sensitive adhesive layer 2 without gaps. That is, the laminated structure of the first adhesive layer 1 and the second adhesive layer 2 can serve as a sealing material for each LED chip 7 .

In this embodiment, the first adhesive layer 1 seals between the LED chips 7 arranged on the display panel and the metal wiring layer 6 . Since the visible light transmittance of the first pressure-sensitive adhesive layer 1 is lower than the visible light transmittance of the second pressure-sensitive adhesive layer 2, it has sufficient light shielding properties in the visible light region. Since the first pressure-sensitive adhesive layer 1 having a higher light shielding property seals the spaces between the LED chips 7 without gaps, it is possible to prevent color mixing between the LED chips 7 and improve the contrast. In addition, since the first pressure-sensitive adhesive layer 1 having a higher light-shielding property also seals the surface of the metal wiring layer 6 , reflection by the metal wiring layer 6 can be prevented.

In this embodiment, the second pressure-sensitive adhesive layer 2 seals the upper portion (display image side) of each LED chip 7 arranged on the display panel. Since the visible light transmittance of the second pressure-sensitive adhesive layer 2 is higher than the visible light transmittance of the first pressure-sensitive adhesive layer 1, it has sufficient transparency in the visible light region. Since the second adhesive layer 2 with higher transparency seals the upper portion (on the display image side) of each LED chip 7, the absorption of visible light emitted from each LED chip 7 is suppressed low, and the luminous efficiency is improved. can be made higher, thus making the image brighter. In addition, since it is not necessary to raise the output to increase the emission luminance, the power consumption can be kept low.

The mini/micro LED display device of this embodiment can be manufactured by bonding a display panel in which a plurality of LED chips are arranged on one side of a substrate and the first adhesive layer of the optical laminate of this embodiment. . In that case, the base material 3 can serve as a cover member forming the outermost layer of the self-luminous display device (mini/micro LED display device). Therefore, according to this embodiment, the step of separately attaching the cover member can be omitted, the necessary members and the number of steps are reduced, and the production efficiency can be improved.

In the mini/micro LED display device 21 of the present embodiment, the surface 3a of the base material 3 is subjected to antireflection treatment and/or antiglare treatment 4. In the mini/micro LED display device 22, the base material 3 An anti-glare layer 4a is formed on the surface 3a as an antireflection treatment. The anti-reflection treatment and/or anti-glare treatment 4, particularly the anti-glare layer 4a, prevents deterioration of visibility due to reflection of external light and reflection of images on the surface 3a of the base material 3 as a cover member, and/or improves glossiness. Appearance such as degree is adjusted.
Each configuration will be described in detail below.

<Base material>
In the present embodiment, the substrate 3 is not particularly limited, but examples thereof include glass and transparent plastic film substrates. The transparent plastic film substrate is not particularly limited, but preferably has excellent visible light transmittance and excellent transparency (preferably haze value of 5% or less). and the transparent plastic film substrate described in . As the transparent plastic film substrate, one having optically low birefringence is preferably used. In this embodiment, the substrate 3 can be used, for example, as a cover member of a self-luminous display device. In this case, the transparent plastic film substrate may be triacetyl cellulose (TAC), polycarbonate, acrylic A film formed from a polyolefin having a cyclic or norbornene structure or the like is preferable. Moreover, in this embodiment, the base material 3 may be the cover member itself. With such a configuration, the step of separately laminating the cover member in the manufacture of the self-luminous display device can be eliminated, so the number of steps and required members can be reduced, and the production efficiency can be improved. Moreover, with such a configuration, the thickness of the cover member can be reduced. In addition, when the base material 3 is a cover member, the surface 3a is the outermost surface of the self-luminous display device.

In the optical laminate of this embodiment, the visible light transmittance T ₁ of the first adhesive layer 1 and the visible light transmittance T ₃ of the substrate 3 preferably satisfy T ₁ <T ₃ . In this configuration, the substrate 3 exhibiting a higher visible light transmittance than the first adhesive layer 1 is positioned above the light emitting element (on the image display side), thereby improving the luminous efficiency and brightening the image. This is preferable in that power consumption due to an increase in output for increasing luminance can be reduced. The visible light transmittance T ₃ of the substrate 3 is not particularly limited, but is, for example, 85 to 100%, and may be 88% or more, 90% or more, or 92% or more.

In the present embodiment, the thickness of the base material 3 is not particularly limited. ~300 μm, optimally between 30 and 200 μm. Although the refractive index of the base material 3 is not particularly limited, it is, for example, in the range of 1.30 to 1.80, preferably in the range of 1.40 to 1.70.

In this embodiment, the surface 3a of the substrate 3 is preferably subjected to a reflective surface treatment and/or an antiglare treatment 4. When the surface 3a of the base material 3 is subjected to the reflective surface treatment and/or the antiglare treatment 4, the surface 3a becomes the outermost surface of the self-luminous display device, and the visibility due to reflection of external light, image reflection, etc. can be prevented from decreasing, or appearance such as glossiness can be adjusted. Anti-glare treatments are preferred as they are easy to manufacture and low in cost.

As the antireflection treatment, any known antireflection treatment can be used without particular limitation, and examples thereof include antireflection (AR) treatment.

As the antireflection (AR) treatment, a known AR treatment can be applied without particular limitation. It can be carried out by forming an antireflection layer (AR layer) in which two or more layers of optical thin films are laminated. The AR layer exerts an antireflection function by canceling out the reversed phases of the incident light and the reflected light using the interference effect of light. The wavelength region of visible light that exhibits the antireflection function is, for example, 380 to 780 nm, and the wavelength region with particularly high luminosity is in the range of 450 to 650 nm. It is preferable to design the AR layer so that

The AR layer generally includes a multi-layer antireflection layer having a structure in which two to five optical thin layers (thin films whose thickness and refractive index are strictly controlled) are laminated. By forming multiple layers with a thickness of , the degree of freedom in the optical design of the AR layer increases, the anti-reflection effect can be further improved, and the spectral reflection characteristics can be made uniform (flat) in the visible light region. become. Since the optical thin film requires high thickness accuracy, each layer is generally formed by dry methods such as vacuum deposition, sputtering, and CVD.

As the anti-glare (AG) treatment, a known AG treatment can be applied without particular limitation. As the anti-glare layer 4a, any known layer can be used without limitation, and it is generally formed as a layer in which inorganic or organic particles are dispersed as an anti-glare agent in a resin.

In this embodiment, the antiglare layer 4a is formed using an antiglare layer-forming material containing a resin, particles, and a thixotropy-imparting agent. A convex portion is formed on the . With this configuration, the anti-glare layer 4a has excellent display characteristics that achieve both anti-glare properties and prevention of white blurring, and even though the anti-glare layer is formed by utilizing particle aggregation, there are no defects in appearance. The production yield of products can be improved by preventing the occurrence of projections on the surface of the antiglare layer.

Examples of the resin include thermosetting resins and ionizing radiation-curable resins that are cured by ultraviolet light or light. As the resin, it is possible to use a commercially available thermosetting resin, ultraviolet curable resin, or the like.

As the thermosetting resin or UV-curable resin, for example, a curable compound having at least one of an acrylate group and a methacrylate group that is cured by heat, light (ultraviolet rays, etc.), electron beams, or the like can be used. Silicone resins, polyester resins, polyether resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, oligomers or prepolymers such as acrylates and methacrylates of polyfunctional compounds such as polyhydric alcohols. can give. These may be used individually by 1 type, and may use 2 or more types together.

For the resin, for example, a reactive diluent having at least one of an acrylate group and a methacrylate group can be used. As the reactive diluent, for example, reactive diluents described in JP-A-2008-88309 can be used, and examples include monofunctional acrylates, monofunctional methacrylates, polyfunctional acrylates, polyfunctional methacrylates, and the like. As the reactive diluent, tri- or more functional acrylates and tri- or more functional methacrylates are preferable. This is because the hardness of the antiglare layer 4a can be improved. Examples of the reactive diluent include butanediol glycerol ether diacrylate, isocyanuric acid acrylate, and isocyanuric acid methacrylate. These may be used individually by 1 type, and may use 2 or more types together.

The particles for forming the antiglare layer 4a have a main function of making the surface of the formed antiglare layer 4a uneven to impart antiglare properties and controlling the haze value of the antiglare layer 4a. The haze value of the antiglare layer 4a can be designed by controlling the refractive index difference between the particles and the resin. Examples of the particles include inorganic particles and organic particles. The inorganic particles are not particularly limited, and examples include silicon oxide particles, titanium oxide particles, aluminum oxide particles, zinc oxide particles, tin oxide particles, calcium carbonate particles, barium sulfate particles, talc particles, kaolin particles, calcium sulfate particles, and the like. is given. The organic particles are not particularly limited, and examples include polymethyl methacrylate resin powder (PMMA fine particles), silicone resin powder, polystyrene resin powder, polycarbonate resin powder, acrylic styrene resin powder, benzoguanamine resin powder, melamine resin powder, polyolefin. Examples thereof include resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, polyethylene fluoride resin powder and the like. One type of these inorganic particles and organic particles may be used alone, or two or more types may be used in combination.

The weight average particle size (D) of the particles is preferably in the range of 2.5 to 10 μm. By setting the weight-average particle size of the particles within the above range, for example, the anti-glare property is more excellent and white blurring can be prevented. The weight average particle size of the particles is more preferably in the range of 3-7 μm. The weight-average particle diameter of the particles can be measured, for example, by the Coulter counting method. For example, using a particle size distribution measuring device (trade name: Coulter Multisizer, manufactured by Beckman Coulter, Inc.) using the pore electrical resistance method, the volume of the electrolyte solution corresponding to the volume of the particles when the particles pass through the pores. By measuring the electrical resistance, the number and volume of the particles are measured, and the weight average particle diameter is calculated.

The shape of the particles is not particularly limited, and may be, for example, a substantially spherical bead shape, or an irregular shape such as a powder. They are substantially spherical particles with a ratio of 1.5 or less, most preferably spherical particles.

The proportion of the particles in the antiglare layer 4a is preferably in the range of 0.2 to 12 parts by weight, more preferably in the range of 0.5 to 12 parts by weight, and still more preferably 1 part by weight, with respect to 100 parts by weight of the resin. ~7 parts by weight. By setting it within the above range, for example, it is possible to achieve more excellent anti-glare properties and prevent white blurring.

Examples of the thixotropy imparting agent for forming the antiglare layer 4a include organic clay, polyolefin oxide, modified urea, and the like.

The organoclay is preferably an organized clay in order to improve affinity with the resin. Examples of organic clays include layered organic clays. The organic clay may be self-prepared, or a commercially available product may be used. Examples of the commercially available products include Lucentite SAN, Lucentite STN, Lucentite SEN, Lucentite SPN, Somasif ME-100, Somasif MAE, Somasif MTE, Somasif MEE, Somasif MPE (trade names, all of which are manufactured by Co-op Chemical Co., Ltd.). ) manufactured); Organite, Organite D, Organite T (trade names, all manufactured by Hojun Co., Ltd.); Kunipia F, Kunipia G, Kunipia G4 (trade names, manufactured by Kunimine Industry Co., Ltd.); Thixogel VZ, Kraton HT , Kraton 40 (trade name, both manufactured by Rockwood Additives), and the like.

The oxidized polyolefin may be self-prepared or a commercially available product may be used. Examples of the commercially available products include Disparlon 4200-20 (trade name, manufactured by Kusumoto Kasei Co., Ltd.) and Flownon SA300 (trade name, manufactured by Kyoeisha Chemical Co., Ltd.).

The modified urea is a reaction product of an isocyanate monomer or its adduct and an organic amine. The modified urea may be self-prepared, or a commercially available product may be used. Examples of the commercial product include BYK410 (manufactured by Big Chemie).

The thixotropy-imparting agents may be used alone or in combination of two or more.

In the present embodiment, it is preferable that the height of the convex portion from the roughness average line of the antiglare layer 4a is less than 0.4 times the thickness of the antiglare layer 4a. More preferably, it is in the range of 0.01 times or more and less than 0.4 times, and still more preferably in the range of 0.01 times or more and less than 0.3 times. If it is within this range, it is possible to suitably prevent the formation of protrusions that would cause defects in appearance on the convex portion. The anti-glare layer 4a of the present embodiment can make it difficult to cause appearance defects by having the convex portions with such heights. Here, the height from the average line can be measured, for example, by the method described in JP-A-2017-138620.

The ratio of the thixotropy imparting agent in the antiglare layer 4a is preferably in the range of 0.1 to 5 parts by weight, more preferably in the range of 0.2 to 4 parts by weight, with respect to 100 parts by weight of the resin.

Although the thickness (d) of the antiglare layer 4a is not particularly limited, it is preferably in the range of 3 to 12 μm. By setting the thickness (d) of the antiglare layer 4a within the above range, for example, curling of the optical layered body 12 can be prevented, and the problem of reduced productivity such as poor transportability can be avoided. Further, when the thickness (d) is within the above range, the weight average particle size (D) of the particles is preferably within the range of 2.5 to 10 μm as described above. When the thickness (d) of the antiglare layer 4a and the weight average particle size (D) of the particles are in the above-described combination, the antiglare property can be further improved. The thickness (d) of the antiglare layer 4a is more preferably in the range of 3-8 μm.

The relationship between the thickness (d) of the antiglare layer 4a and the weight average particle size (D) of the particles is preferably within the range of 0.3≦D/d≦0.9. By having such a relationship, it is possible to obtain an anti-glare layer that is more excellent in anti-glare properties, can prevent white blurring, and has no defects in appearance.

In the optical layered body 12 of the present embodiment, as described above, the antiglare layer 4a forms convex portions on the surface of the antiglare layer 4a by aggregation of the particles and the thixotropy-imparting agent. In the aggregated portion forming the convex portion, the particles are present in a state of being gathered in plural in the surface direction of the antiglare layer 4a. As a result, the convex portion has a gentle shape. Since the anti-glare layer 4a of the present embodiment has convex portions having such a shape, it is possible to maintain anti-glare properties, prevent white blurring, and make it difficult for appearance defects to occur. can.

The surface shape of the antiglare layer 4a can be arbitrarily designed by controlling the aggregation state of the particles contained in the antiglare layer forming material. The aggregation state of the particles can be controlled by, for example, the material of the particles (for example, chemically modified state of the particle surface, affinity for solvent or resin, etc.), type of resin (binder) or solvent, combination, and the like. Here, in the present embodiment, the aggregation state of the particles can be controlled by the thixotropy imparting agent contained in the antiglare layer-forming material. As a result, in the present embodiment, the particles can be agglomerated as described above, and the convex portion can have a gentle shape.

In the optical layered body 12 of the present embodiment, when the substrate 3 is made of resin or the like, it preferably has a permeation layer at the interface between the substrate 3 and the antiglare layer 4a. The permeation layer is formed by permeating the base material 3 with a resin component contained in the material forming the antiglare layer 4a. The formation of the permeation layer is preferable because the adhesion between the substrate 3 and the antiglare layer 4a can be improved. The permeation layer preferably has a thickness in the range of 0.2 to 3 μm, more preferably in the range of 0.5 to 2 μm. For example, when the base material 3 is triacetyl cellulose and the resin contained in the antiglare layer 4a is an acrylic resin, the penetration layer can be formed. The permeation layer can be confirmed and the thickness can be measured, for example, by observing a cross section of the optical layered body 12 with a transmission electron microscope (TEM).

In the present embodiment, even when applied to the optical layered body 12 having such a permeation layer, it is possible to easily form a desired smooth uneven surface shape that achieves both anti-glare properties and prevention of white blurring. can be done. It is preferable to form the permeation layer thicker in order to improve the adhesion of the substrate 3 having poorer adhesion to the anti-glare layer 4a.

In the present embodiment, the antiglare layer 4a preferably has one or less appearance defect having a maximum diameter of 200 μm or more per 1 m ² of the antiglare layer 4a. More preferably, it does not have the appearance defect.

In this embodiment, the substrate 3 on which the antiglare layer 4a is formed preferably has a haze value within the range of 0 to 10%. The haze value is a haze value (cloudiness) according to JIS K 7136 (2000 version). The haze value is more preferably in the range of 0 to 5%, still more preferably in the range of 0 to 3%. In order to keep the haze value within the above range, it is preferable to select the particles and the resin so that the refractive index difference between the particles and the resin is in the range of 0.001 to 0.02. When the haze value is within the above range, a clear image can be obtained and the contrast in a dark place can be improved.

In this embodiment, the uneven shape of the surface of the antiglare layer 4a has an average inclination angle θa (°) of . It is preferably in the range of 1 to 5.0, more preferably in the range of 0.3 to 4.5, even more preferably in the range of 1.0 to 4.0, and 1.6 to 4.0. .0 is particularly preferred. Here, the average tilt angle θa is a value defined by the following formula (1). The average tilt angle θa is, for example, a value measured by the method described in JP-A-2017-138620.
Average tilt angle θa=tan-1Δa (1)

In the above formula (1), Δa is, as shown in the following formula (2), in the reference length L of the roughness curve defined in JIS B 0601 (1994 edition), the distance between the top and the valley of the adjacent peaks It is a value obtained by dividing the sum (h1+h2+h3 . The roughness curve is a curve obtained by removing surface waviness components longer than a predetermined wavelength from the cross-sectional curve with a phase difference compensation type high-pass filter. Further, the cross-sectional curve is a contour that appears at the cut end when the target plane is cut along a plane perpendicular to the target plane.
Δa=(h1+h2+h3...+hn)/L (2)

When θa is within the above range, the anti-glare property is more excellent, and white blurring can be prevented.

In forming the antiglare layer 4a, the prepared antiglare layer forming material (coating liquid) preferably exhibits thixotropy, and the Ti value defined below is in the range of 1.3 to 3.5. is preferred, and more preferably in the range of 1.3 to 2.8.
Ti value = β1/β2
Here, β1 is the viscosity measured at a shear rate of 20 (1/s) using HAAKE's Rheostress 6000, and β2 is the viscosity measured using HAAKE's Rheostress 6000 at a shear rate of 200 (1/s). Viscosity measured under conditions.

If the Ti value is less than 1.3, defects in appearance tend to occur, and anti-glare properties and white blur characteristics deteriorate. On the other hand, when the Ti value exceeds 3.5, the particles are less likely to agglomerate and more likely to be in a dispersed state.

The method for producing the antiglare layer 4a of the present embodiment is not particularly limited, and it may be produced by any method. liquid) is prepared, the antiglare layer forming material (coating liquid) is applied to the surface 3a of the base material 3 to form a coating film, and the coating film is cured to form the antiglare layer 4a. , can be manufactured. In this embodiment, a transfer method using a mold, a method of imparting an uneven shape by an appropriate method such as sandblasting or an embossing roll, or the like can be used together.

The solvent is not particularly limited, and various solvents can be used. One type may be used alone, or two or more types may be used in combination. There is an optimum solvent type and solvent ratio depending on the composition of the resin, the types and contents of the particles and the thixotropy-imparting agent, and the like. Examples of solvents include, but are not limited to, alcohols such as methanol, ethanol, isopropyl alcohol, butanol, and 2-methoxyethanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclopentanone; methyl acetate, ethyl acetate. , Esters such as butyl acetate; Ethers such as diisopropyl ether and propylene glycol monomethyl ether; Glycols such as ethylene glycol and propylene glycol; Cellosolves such as ethyl cellosolve and butyl cellosolve; Aliphatic hydrocarbons such as hexane, heptane and octane Aromatic hydrocarbons such as benzene, toluene, and xylene.

For example, when triacetyl cellulose (TAC) is used as the substrate 3 to form the permeation layer, a good solvent for TAC can be suitably used. Examples of the solvent include ethyl acetate, methyl ethyl ketone, cyclopentanone and the like.

Further, by appropriately selecting the solvent, the thixotropy of the antiglare layer-forming material (coating liquid) by the thixotropy-imparting agent can be exhibited satisfactorily. For example, when organoclays are used, toluene and xylene can be suitably used alone or in combination. They can be used or used in combination. For example, when modified urea is used, butyl acetate and methyl isobutyl ketone can be preferably used alone or in combination.

Various leveling agents can be added to the antiglare layer-forming material. As the leveling agent, for example, a fluorine-based or silicone-based leveling agent can be used for the purpose of preventing coating unevenness (uniformizing the coated surface). In this embodiment, depending on the case where the antifouling property is required on the surface of the antiglare layer 4a, or the case where an antireflection layer (low refractive index layer) or a layer containing an interlayer filler is formed on the antiglare layer 4a. Therefore, the leveling agent can be appropriately selected. In the present embodiment, for example, the thixotropic property can be expressed in the coating liquid by including the thixotropy-imparting agent, so uneven coating is less likely to occur. For this reason, this embodiment has an advantage that, for example, the options for the leveling agent can be expanded.

The amount of the leveling agent compounded is, for example, 5 parts by weight or less, preferably in the range of 0.01 to 5 parts by weight, per 100 parts by weight of the resin.

Pigments, fillers, dispersants, plasticizers, UV absorbers, surfactants, antifouling agents, antioxidants and the like are added to the antiglare layer-forming material as necessary within a range that does not impair the performance. may These additives may be used singly or in combination of two or more.

Conventionally known photopolymerization initiators, such as those described in JP-A-2008-88309, can be used for the anti-glare layer-forming material.

Examples of methods for applying the anti-glare layer-forming material onto the surface 3a of the substrate 3 include a fountain coating method, a die coating method, a spin coating method, a spray coating method, a gravure coating method, a roll coating method, and a bar coating method. etc. can be used.

The antiglare layer-forming material is applied to form a coating film on the substrate 3, and the coating film is cured. It is preferable to dry the coating film prior to the curing. The drying may be, for example, natural drying, air drying by blowing air, heat drying, or a combination thereof.

The means for curing the coating film of the anti-glare layer-forming material is not particularly limited, but ultraviolet curing is preferable. The irradiation amount of the energy beam source is preferably 50 to 500 mJ/cm ² as an integrated exposure amount at an ultraviolet wavelength of 365 nm. When the irradiation dose is 50 mJ/cm ² or more, the curing becomes more sufficient, and the hardness of the formed anti-glare layer becomes more sufficient. Also, if it is 500 mJ/cm ² or less, coloring of the formed antiglare layer can be prevented.

The antiglare layer 4a can be formed on the surface 3a of the substrate 3 in the manner described above. The anti-glare layer 4a may be formed by a manufacturing method other than the method described above. The hardness of the antiglare layer 4a of the present embodiment is preferably 2H or higher in terms of pencil hardness, although it is also affected by the thickness of the layer.

In this embodiment, the anti-glare layer anti-glare layer 4a may have a multi-layer structure in which two or more layers are laminated.

In this embodiment, the above-described AR layer (low refractive index layer) may be arranged on the antiglare layer 4a. For example, when the optical layered body 12 according to the present embodiment is attached to a self-luminous display device, one factor that reduces the visibility of images is the reflection of light at the interface between the air and the antiglare layer. The AR layer reduces the surface reflection. The antiglare layer 3a and the antireflection layer may each have a multi-layer structure in which two or more layers are laminated.

In addition, in order to prevent the adhesion of contaminants and improve the ease of removal of adhered contaminants, a contamination prevention layer formed of a fluorine group-containing silane compound or a fluorine group-containing organic compound is provided on the anti-glare layer 4a. Lamination is preferred.

In this embodiment, it is preferable to subject at least one of the substrate 3 and the antiglare layer 4a to surface treatment. If the surface of the substrate 3 is surface-treated, the adhesion with the anti-glare layer 4a is further improved. Moreover, if the surface of the anti-glare layer 4a is treated, the adhesion to the AR layer is further improved.

In order to prevent the base material 3 from curling, the other surface of the antiglare layer 4a may be subjected to a solvent treatment. Moreover, in order to prevent curling, a transparent resin layer may be formed on the other surface of the antiglare layer 4a.

<Adhesive layer>
In the present embodiment, the first pressure-sensitive adhesive layer 1 and the second pressure-sensitive adhesive layer 2 are pressure-sensitive adhesive layers formed from a pressure-sensitive adhesive composition selected from photocurable pressure-sensitive adhesive compositions and solvent-based pressure-sensitive adhesive compositions. .

In the present embodiment, the first pressure-sensitive adhesive layer 1 and the second pressure-sensitive adhesive layer 2 may both be pressure-sensitive adhesive layers formed from a photocurable pressure-sensitive adhesive composition, and both may be solvent-based pressure-sensitive adhesive compositions. It may be a pressure-sensitive adhesive layer formed from, one is a pressure-sensitive adhesive layer formed from a photocurable pressure-sensitive adhesive composition, and the other is a pressure-sensitive adhesive layer formed from a solvent-type pressure-sensitive adhesive composition, good too.

In the present embodiment, the first pressure-sensitive adhesive layer 1 is preferably a pressure-sensitive adhesive layer formed from a solvent-based pressure-sensitive adhesive composition in terms of excellent step absorbability and excellent workability. On the other hand, the second pressure-sensitive adhesive layer 2 may be a pressure-sensitive adhesive layer formed from a photocurable pressure-sensitive adhesive composition or a pressure-sensitive adhesive layer formed from a solvent-based pressure-sensitive adhesive composition.

The pressure-sensitive adhesive composition forming the first pressure-sensitive adhesive layer 1 preferably contains a colorant. When the pressure-sensitive adhesive composition forming the first pressure-sensitive adhesive layer 1 contains a coloring agent, the transparency of the first pressure-sensitive adhesive layer 1 to visible light is reduced, and the T ₁ and the T ₂ are such that T ₁ <T. ₂ is preferable. The first pressure-sensitive adhesive layer 1, which has reduced permeability to visible light and is imparted with a light-shielding property, is provided between the metal wiring layer 6 and the LED chip of the self-luminous display device (mini/micro LED display device) of the present embodiment. Sealing prevents reflection from metal wiring or the like, prevents color mixture between LED chips, and improves image contrast.

The pressure _- sensitive adhesive composition forming the second pressure _- sensitive adhesive layer ₂ may contain _a coloring agent. preferably does not contain

<Photocurable adhesive composition>
The photocurable pressure-sensitive adhesive composition contains a polymer, a photopolymerizable compound, and a photopolymerization initiator. That is, the photocurable pressure-sensitive adhesive composition used for forming the first pressure-sensitive adhesive layer 1 and the second pressure-sensitive adhesive layer 2 of the present embodiment contains a polymer, a photopolymerizable compound, and a photopolymerization initiator. .

The pressure-sensitive adhesive layer formed using the photocurable pressure-sensitive adhesive composition is a type that performs photocuring (first form), and a type that does not perform photocuring and performs photocuring after bonding with a display panel described later. It is roughly divided into type (second form). Both the first pressure-sensitive adhesive layer 1 and the second pressure-sensitive adhesive layer 2 may be pressure-sensitive adhesive layers of the first type, both may be pressure-sensitive adhesive layers of the second type, or one of them may be the pressure-sensitive adhesive layer of the second type. One form of pressure-sensitive adhesive layer and the other may be a second form of pressure-sensitive adhesive layer.

[First form]
The pressure-sensitive adhesive layer of the first form is formed by applying a photocurable pressure-sensitive adhesive composition containing a polymer, a photopolymerizable compound, and a photopolymerization initiator onto a release film and performing photocuring. can do.

<Photocurable adhesive composition>
(polymer)
Polymers contained in the photocurable pressure-sensitive adhesive composition include acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyvinyl ethers, vinyl acetate/vinyl chloride copolymers, modified polyolefins, epoxies, fluorines, and natural rubbers. and rubber-based polymers such as synthetic rubbers. In particular, an acrylic polymer is preferably used because it exhibits appropriate adhesive properties such as wettability, cohesiveness, and adhesiveness, and is also excellent in weather resistance, heat resistance, and the like.

The acrylic polymer contains a (meth)acrylic acid alkyl ester as a main constituent monomer component. In addition, in this specification, "(meth)acryl" means acryl and/or methacryl. The amount of (meth)acrylic acid alkyl ester is preferably 50% by weight or more, more preferably 55% by weight or more, and still more preferably 60% by weight or more, relative to the total amount of monomer components constituting the acrylic polymer.

As the (meth)acrylic acid alkyl ester, a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms is preferably used. The (meth)acrylic acid alkyl ester may have a branched alkyl group or a cyclic alkyl group.

Specific examples of (meth)acrylic acid alkyl esters having a chain alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, and (meth)acrylate. s-butyl acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, neopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate , undecyl (meth)acrylate, dodecyl (meth)acrylate, isotridodecyl (meth)acrylate, tetradecyl (meth)acrylate, isotetradecyl (meth)acrylate, pentadecyl (meth)acrylate, (meth)acrylate cetyl acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, isooctacyl (meth)acrylate, nonadecyl (meth)acrylate and the like. Preferred alkyl (meth)acrylates having a chain alkyl group used in the first embodiment include butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octadecyl (meth)acrylate, and (meth)acrylic acid. dodecyl acid. The amount of (meth)acrylic acid alkyl ester having a chain alkyl group with respect to the total amount of monomer components constituting the acrylic polymer is, for example, about 40 to 90% by weight, and 45 to 80% by weight or 50 to 70% by weight. There may be.

Specific examples of (meth)acrylic acid alkyl esters having an alicyclic alkyl group include cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, and cyclooctyl (meth)acrylate. (meth) acrylic acid cycloalkyl ester; (meth) acrylic acid ester having a bicyclic aliphatic hydrocarbon ring such as isobornyl (meth) acrylate; dicyclopentanyl (meth) acrylate, dicyclopentanyloxy Tricyclics such as ethyl (meth)acrylate, tricyclopentanyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate (Meth)acrylic acid esters having the above aliphatic hydrocarbon ring can be mentioned. Preferred alkyl (meth)acrylates having an alicyclic alkyl group used in the first embodiment are cyclohexyl (meth)acrylate and isobornyl (meth)acrylate. The amount of (meth)acrylic acid alkyl ester having an alicyclic alkyl group relative to the total amount of the monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, 5 to 40% by weight or 10 to 30% by weight. may be

The acrylic polymer may contain polar group-containing monomers such as hydroxyl group-containing monomers, carboxy group-containing monomers, and nitrogen-containing monomers as constituent monomer components. By including a polar group-containing monomer as a constituent monomer component of the acrylic polymer, the cohesive force of the pressure-sensitive adhesive tends to be enhanced and the adhesive force tends to be improved. Preferred polar group-containing monomers used in the first embodiment are hydroxyl group-containing monomers and nitrogen-containing monomers. The amount of the polar group-containing monomer (the sum of the hydroxyl group-containing monomer, the carboxy group-containing monomer, and the nitrogen-containing monomer) relative to the total amount of the monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and 5 to 40% by weight. % or 10-30% by weight.

Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and (meth)acrylic acid. (Meth)acrylic acid esters such as 8-hydroxyoctyl acid, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate and (4-hydroxymethylcyclohexyl)-methyl (meth)acrylate . When the isocyanate cross-linking agent introduces a cross-linked structure into the polymer, the hydroxyl group can become a reaction point (cross-linking point) with the isocyanate group. Preferred hydroxyl group-containing monomers used in the first embodiment are 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate. The amount of the hydroxyl group-containing monomer relative to the total amount of monomer components constituting the acrylic polymer is, for example, approximately 3 to 50% by weight, and may be 5 to 40% by weight or 10 to 30% by weight.

Carboxy group-containing monomers include acrylic monomers such as (meth)acrylic acid, carboxyethyl (meth)acrylate, and carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and the like. . When the epoxy-based cross-linking agent introduces a cross-linked structure into the polymer, the carboxy group can serve as a reaction point (cross-linking point) with the epoxy group. A preferred carboxy group-containing monomer used in the first embodiment is (meth)acrylic acid. The amount of the carboxy group-containing monomer relative to the total amount of monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and may be 5 to 40% by weight or 10 to 30% by weight.

Nitrogen-containing monomers include N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, (meth)acryloylmorpholine, N-vinyl Vinyl monomers such as carboxylic acid amides, N-vinylcaprolactam and acrylamide, and cyano group-containing monomers such as acrylonitrile and methacrylonitrile can be used. A preferred nitrogen-containing monomer for use in the first form is N-vinylpyrrolidone. The amount of the nitrogen-containing monomer relative to the total amount of monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and may be 5 to 40% by weight or 10 to 30% by weight.

The acrylic polymer contains, as monomer components other than the above (sometimes referred to as "other monomers"), an acid anhydride group-containing monomer, a caprolactone adduct of (meth)acrylic acid, a sulfonic acid group-containing monomer, and a phosphoric acid group-containing monomer. Monomers, vinyl-based monomers such as vinyl acetate, vinyl propionate, styrene, α-methylstyrene; epoxy group-containing monomers such as glycidyl (meth)acrylate; polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate , methoxyethylene glycol (meth)acrylate, glycol-based acrylic ester monomers such as methoxypolypropylene glycol (meth)acrylate; tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, silicone (meth)acrylate and (meth) Acrylic acid ester monomers such as 2-methoxyethyl acrylate may also be included.

The glass transition temperature (Tg) of the polymer contained in the photocurable pressure-sensitive adhesive composition is preferably 0°C or lower. The glass transition temperature of the polymer may be -5°C or lower, -10°C or lower, or -15°C or lower. The glass transition temperature of a polymer is the peak top temperature of the loss tangent (tan δ) determined by dynamic viscoelasticity measurements. When a crosslinked structure is introduced into the polymer, the glass transition temperature can be calculated based on the theoretical Tg from the composition of the polymer. The theoretical Tg is calculated by the Fox equation described later.

A polymer is obtained by polymerizing the above monomer components by various known methods. Although the polymerization method is not particularly limited, it is preferable to prepare the polymer by photopolymerization. Since a polymer can be prepared by photopolymerization without using a solvent, it is not necessary to remove the solvent by drying when forming the pressure-sensitive adhesive layer, and a thick pressure-sensitive adhesive layer can be uniformly formed.

In the preparation of the pressure-sensitive adhesive layer of the first mode, it is preferable to prepare a low polymerization degree polymer (prepolymer) in which a part of the monomer components remain unreacted. The composition used for preparing the prepolymer (prepolymer-forming composition) preferably contains a photopolymerization initiator in addition to the monomers. A photopolymerization initiator may be appropriately selected according to the type of monomer. For example, a radical photopolymerization initiator is used for polymerization of an acrylic polymer. Examples of photopolymerization initiators include benzoin ether-based photopolymerization initiators, acetophenone-based photopolymerization initiators, α-ketol-based photopolymerization initiators, aromatic sulfonyl chloride-based photopolymerization initiators, photoactive oxime-based photopolymerization initiators, Examples include benzoin-based photopolymerization initiators, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, and acylphosphine oxide-based photopolymerization initiators.

In the polymerization, a chain transfer agent, a polymerization inhibitor (polymerization retarder), or the like may be used for the purpose of molecular weight adjustment or the like. Chain transfer agents include thiols such as α-thioglycerol, lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, 2,3-dimercapto-1-propanol, Examples include α-methylstyrene dimer and the like.

Although the polymerization rate of the prepolymer is not particularly limited, it is preferably 3 to 50% by weight, more preferably 5 to 40% by weight, from the viewpoint of obtaining a viscosity suitable for coating on a substrate. The polymerization rate of the prepolymer can be adjusted within a desired range by adjusting the type and amount of the photopolymerization initiator used, and the irradiation intensity and irradiation time of actinic rays such as UV light. The polymerization rate of the prepolymer is the non-volatile content when heated at 130° C. for 3 hours, and is calculated by the following formula. The rate of polymerization (non-volatile content) of the pressure-sensitive adhesive layer is also measured by the same method.
Polymerization rate (%) = weight after heating/weight before heating x 100

As described above, the photocurable pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer contains a polymer, a photopolymerizable compound, and a photopolymerization initiator. For example, a photocurable pressure-sensitive adhesive composition can be obtained by adding a photopolymerizable compound and a photopolymerization initiator to a prepolymer. Instead of using a prepolymer, a low-molecular-weight polymer (oligomer) is used, and the low-molecular-weight polymer is mixed with a photopolymerizable compound, a photopolymerization initiator, and a colorant to prepare a photocurable pressure-sensitive adhesive composition. may

(Photopolymerizable compound)
The photopolymerizable compound contained in the photocurable pressure-sensitive adhesive composition has one or more photopolymerizable functional groups in one molecule. The photopolymerizable functional group may be either radically polymerizable, cationic polymerizable or anionic polymerizable. is preferred.

A prepolymer contains a polymer and unreacted monomers, and the unreacted monomers retain photopolymerizability. Therefore, it is not always necessary to add a photopolymerizable compound in the preparation of the photocurable pressure-sensitive adhesive composition. When a photopolymerizable compound is added to the prepolymer, the photopolymerizable compound to be added may be the same as or different from the monomer used for preparing the prepolymer.

When the polymer is an acrylic polymer, the compound to be added as the photopolymerizable compound is preferably a monomer or oligomer having a (meth)acryloyl group as the photopolymerizable functional group, since it has high compatibility with the polymer. The photopolymerizable compound may be a polyfunctional compound having two or more photopolymerizable functional groups in one molecule. A polyfunctional (meth)acrylate is mentioned as a photopolymerizable polyfunctional compound. Polyfunctional (meth)acrylates include polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, bisphenol A ethylene oxide-modified di(meth)acrylate, bisphenol A propylene oxide Modified di(meth)acrylate, alkanediol di(meth)acrylate, tricyclodecanedimethanol di(meth)acrylate, pentaerythritol di(meth)acrylate, neopentyl glycol di(meth)acrylate, glycerin di(meth)acrylate , urethane di(meth)acrylate and the like; trifunctional (meth)acrylates such as pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, and ethoxylated isocyanurate tri(meth)acrylate; meth)acrylic acid ester; tetrafunctional (meth)acrylic acid ester such as ditrimethylolpropane tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate; dipentaerythritol penta Penta- or higher-functional (meth)acrylic acid esters such as (meth)acrylates and dipentaerythritol hexa(meth)acrylates can be mentioned.

When a polyfunctional compound is used as the photopolymerizable compound, the amount of the polyfunctional compound used is preferably 10 parts by weight or less, more preferably 0.001 to 1 weight part per 100 parts by weight of the polymer (including the prepolymer). parts, more preferably 0.005 to 0.5 parts by weight. If the amount of polyfunctional monomer used is excessively large, the adhesive layer after photocuring may have low viscosity and poor adhesion. The amount of polyfunctional compound used may be 10 parts by weight or less, 5 parts by weight or less, 3 parts by weight or less, or 1 part by weight or less. The amount of polyfunctional monomer used may be 0, 0.001 parts by weight or more, 0.01 parts by weight or more, or 0.1 parts by weight or more.

When a monomer forming a prepolymer is used as the photopolymerizable compound, a hydroxyl group-containing monomer is preferable, and 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are more preferable. When a hydroxyl group-containing monomer is used as the photopolymerizable compound, the amount of the hydroxyl group-containing monomer used is preferably 40 parts by weight or less, more preferably 1 to 30 parts by weight, based on 100 parts by weight of the polymer (including the prepolymer). Yes, more preferably 5 to 20 parts by weight. The amount of the hydroxyl group-containing monomer used may be 40 parts by weight or less, 30 parts by weight or less, or 20 parts by weight or less. The amount of the hydroxyl group-containing monomer used may be 0, or may be 1 part by weight or more, 5 parts by weight or more, or 10 parts by weight or more.

(Photoinitiator)
A photocurable adhesive composition contains a photoinitiator. The photopolymerization initiator generates radicals, acids, bases, etc. by irradiation with actinic rays such as ultraviolet rays, and can be appropriately selected according to the type of the photopolymerizable compound. When the photopolymerizable compound is a compound having a (meth)acryloyl group (for example, a monofunctional or polyfunctional (meth)acrylate), a photoradical polymerization initiator is preferably used as the photopolymerization initiator. A photoinitiator may be used individually and may be used in mixture of 2 or more types.

When the photopolymerization initiator used in the preparation (polymerization) of the polymer (including the prepolymer) remains without being deactivated, the addition of the photopolymerization initiator may be omitted. When adding a photoinitiator to the polymer, the added photoinitiator may be the same as or different from the photoinitiator used in the preparation of the polymer.

The photopolymerization initiator contained in the photocurable pressure-sensitive adhesive composition preferably has an absorption maximum in a wavelength region where the light absorption by the colorant described later is small. Specifically, the photopolymerization initiator preferably has an absorption maximum in the wavelength range of 330 to 400 nm. Since the photopolymerization initiator has an absorption maximum in a region where light absorption by the colorant is small, curing inhibition by the colorant is suppressed, so that the polymerization rate can be sufficiently increased by photocuring. Photoradical polymerization initiators having an absorption maximum in the wavelength region of 330 to 400 nm include hydroxyketones, benzyldimethylketals, aminoketones, acylphosphine oxides, benzophenones, trichloromethyl group-containing triazine derivatives, and the like. .

The content of the photopolymerization initiator in the photocurable pressure-sensitive adhesive composition is 0.01 to 10 parts by weight with respect to 100 parts by weight of the total amount of monomers (monomers used for polymer preparation and photopolymerizable compounds added to the polymer). about 0.05 to 5 parts by weight.

(coloring agent)
The photocurable pressure-sensitive adhesive composition used in the first mode may contain a colorant. In particular, it is preferable that the photocurable pressure-sensitive adhesive composition forming the first pressure-sensitive adhesive layer 1 further contains a colorant. When the photocurable pressure-sensitive adhesive composition forming the first pressure-sensitive adhesive layer 1 contains a coloring agent, the transparency of the first pressure-sensitive adhesive layer 1 to visible light is reduced, and the T ₁ and the T ₂ are T This is preferable in that it satisfies ₁ < T ₂ . The first pressure-sensitive adhesive layer 1, which has reduced permeability to visible light and is imparted with a light-shielding property, is provided between the metal wiring layer 6 and the LED chip of the self-luminous display device (mini/micro LED display device) of the present embodiment. Sealing prevents reflection from metal wiring or the like, prevents color mixture between LED chips, and improves image contrast.

The coloring agent may be either a dye or a pigment as long as it can be dissolved or dispersed in the photocurable pressure-sensitive adhesive composition. Dyes are preferred because they can achieve a low haze even when added in small amounts, and are easy to distribute uniformly without sedimentation like pigments. Pigments are also preferred because they have high color development even when added in small amounts. If a pigment is used as the colorant, it preferably has low or no conductivity. Moreover, when using a dye, it is preferable to use together with the below-mentioned antioxidant etc.

Although the coloring agent is not particularly limited, one that absorbs visible light and has ultraviolet transparency is preferable. That is, the colorant preferably has a higher average transmittance at wavelengths of 330 to 400 nm than at wavelengths of 400 to 700 nm. The transmittance of the colorant is adjusted by an appropriate solvent such as tetrahydrofuran (THF) or a dispersion medium (organic solvent with low absorption in the wavelength range of 330 to 700 nm) so that the transmittance at a wavelength of 400 nm is about 50 to 60%. Measure using diluted solutions or dispersions.

Examples of ultraviolet-transmitting black pigments that absorb ultraviolet light less than that of visible light include "9050BLACK" and "UVBK-0001" manufactured by Tokushiki. Examples of the ultraviolet-transmitting black dye include "SOC-L-0123" manufactured by Orient Chemical Industry Co., Ltd., and the like.

Carbon black and titanium black, which are generally used as black colorants, absorb more ultraviolet light than visible light (the transmittance of ultraviolet light is smaller than the transmittance of visible light). Therefore, when a coloring agent such as carbon black is added to a photocurable pressure-sensitive adhesive composition sensitive to ultraviolet rays, most of the ultraviolet rays irradiated for photocuring are absorbed by the coloring agent, and the amount of light absorbed by the photopolymerization initiator is is small, and photocuring takes time (accumulated amount of irradiation light increases). In addition, when the thickness of the pressure-sensitive adhesive layer is large, less ultraviolet rays reach the surface opposite to the light irradiation surface, so that photocuring tends to be insufficient even if light irradiation is performed for a long time. On the other hand, by using a coloring agent having a higher transmittance for ultraviolet light than for visible light, inhibition of curing due to the coloring agent can be suppressed.

The content of the colorant in the photocurable pressure-sensitive adhesive composition forming the first pressure-sensitive adhesive layer is, for example, about 0.01 to 20 parts by weight with respect to 100 parts by weight of the total amount of monomers, and the type of colorant and , may be appropriately set according to the color tone and light transmittance of the pressure-sensitive adhesive layer. Colorants may be added to the composition as a solution or dispersion dissolved or dispersed in a suitable solvent.

It is preferable that the photocurable pressure-sensitive adhesive composition forming the second pressure-sensitive adhesive layer does not contain a coloring agent. Since the photocurable pressure-sensitive adhesive composition forming the second pressure-sensitive adhesive layer does not contain a coloring agent, the transparency to visible light is increased, and the luminous efficiency of the self-luminous display device (mini/micro LED display device) is improved. improves. When the photocurable pressure-sensitive adhesive composition forming the second pressure-sensitive adhesive layer contains a colorant, its content is, for example, about 0.1 part by weight or less with respect to 100 parts by weight of the total amount of monomers. Even if the photocurable pressure-sensitive adhesive composition forming the second pressure-sensitive adhesive layer does not contain a colorant, the colorant contained in the first pressure-sensitive adhesive layer may migrate to the second pressure-sensitive adhesive layer.

(Silane coupling agent)
The photocurable pressure-sensitive adhesive composition may contain a silane coupling agent as long as the effects of the present invention are not impaired. When the photocurable pressure-sensitive adhesive composition contains a silane coupling agent, the adhesion reliability to glass (in particular, the adhesion reliability to glass under a high-temperature and high-humidity environment) is improved, which is preferable.

Examples of the silane coupling agent include, but are not limited to, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-aminopropyltrimethoxysilane. , 3-acryloxypropyltrimethoxysilane and the like are preferred. Among them, γ-glycidoxypropyltrimethoxysilane is preferred. In addition, as a commercial product, for example, trade name "KBM-403" (manufactured by Shin-Etsu Chemical Co., Ltd.) can be mentioned. In addition, a silane coupling agent may be used individually or in combination of 2 or more types.

The content of the silane coupling agent in the photocurable pressure-sensitive adhesive composition is not particularly limited, but is preferably 0.01 to 1 part by weight, more preferably 0.03 to 0.5 parts by weight, with respect to 100 parts by weight of the polymer. weight part.

(other ingredients)
In the first mode, the photocurable pressure-sensitive adhesive composition may contain components other than the polymer, photopolymerizable compound, photopolymerization initiator and colorant. For example, a chain transfer agent may be included for the purpose of adjusting the photocuring speed. Moreover, an oligomer or a tackifier may be contained for the purpose of adjusting the viscosity of the photocurable pressure-sensitive adhesive composition and adjusting the adhesive strength of the pressure-sensitive adhesive layer. As the oligomer, for example, one having a weight average molecular weight of about 1,000 to 30,000 is used. As the oligomer, an acrylic oligomer is preferable because of its excellent compatibility with the acrylic polymer. The photocurable pressure-sensitive adhesive composition may contain additives such as plasticizers, softeners, antidegradants, fillers, antioxidants, surfactants, and antistatic agents.

[Second form]
The pressure-sensitive adhesive layer of the second form is a type of pressure-sensitive adhesive layer that does not undergo photocuring, and is formed by forming a photocurable pressure-sensitive adhesive composition into a sheet. Since the adhesive layer of the second form contains the photopolymerizable compound in an unreacted state, the adhesive layer has photocurability.

The photocurable pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer of the second mode contains a polymer, a photopolymerizable compound, and a photopolymerization initiator.

(polymer)
As the polymer contained in the pressure-sensitive adhesive composition, as in the first embodiment, various polymers can be applied, and an acrylic polymer is preferably used. The monomer components constituting the acrylic polymer are the same as in the first embodiment.

In order to introduce a crosslinked structure using a crosslinking agent, which will be described later, the monomer component constituting the polymer preferably contains a hydroxy group-containing monomer and/or a carboxy group-containing monomer. For example, when using an isocyanate-based cross-linking agent, it is preferable to contain a hydroxy group-containing monomer as a monomer component. When an epoxy-based cross-linking agent is used, it preferably contains a carboxy group-containing monomer as a monomer.

In the second form, since photocuring is not performed on the base material, in order to form a solid (regular) pressure-sensitive adhesive layer, the polymer contained in the photocurable pressure-sensitive adhesive composition should have a relatively large molecular weight. Used. The weight average molecular weight of the polymer is, for example, about 100,000 to 2,000,000.

Since high-molecular-weight polymers are solid, the pressure-sensitive adhesive composition is preferably a solution in which the polymer is dissolved in an organic solvent. For example, a polymer solution is obtained by solution polymerization of the monomer components. A polymer solution may be prepared by dissolving a solid polymer in an organic solvent.

Ethyl acetate, toluene and the like are generally used as solvents for solution polymerization. The solution concentration is usually about 20 to 80% by weight. Examples of polymerization initiators include azo initiators, peroxide initiators, redox initiators obtained by combining peroxides and reducing agents (for example, combinations of persulfate and sodium hydrogen sulfite, peroxides and ascorbic A thermal polymerization initiator such as a combination of sodium phosphates) is preferably used. The amount of the polymerization initiator used is not particularly limited, but for example, it is preferably about 0.005 to 5 parts by weight, more preferably about 0.02 to 3 parts by weight, relative to 100 parts by weight of the total amount of the monomer components forming the polymer. preferable.

(Photopolymerizable compound)
The photopolymerizable compound contained in the pressure-sensitive adhesive composition in the second mode is the same as described above for the first mode, and a compound having one or more photopolymerizable functional groups is used.

(Photoinitiator)
The photopolymerization initiator contained in the pressure-sensitive adhesive composition in the second mode is the same as that described in the first mode, and preferably has an absorption maximum in the wavelength region of 330 to 400 nm. The amount of the photopolymerization initiator is about 0.01 to 10 parts by weight, preferably about 0.05 to 5 parts by weight, per 100 parts by weight of the polymer.

(coloring agent)
It may contain the pressure-sensitive adhesive composition and colorant used in the second mode. In particular, it is preferable that the photocurable pressure-sensitive adhesive composition forming the first pressure-sensitive adhesive layer 1 further contains a colorant. When the photocurable pressure-sensitive adhesive composition forming the first pressure-sensitive adhesive layer 1 contains a coloring agent, the transparency of the first pressure-sensitive adhesive layer 1 to visible light is reduced, and the T ₁ and the T ₂ are T This is preferable in that it satisfies ₁ < T ₂ . The first pressure-sensitive adhesive layer 1, which has reduced permeability to visible light and is imparted with a light-shielding property, is provided between the metal wiring layer 6 and the LED chip of the self-luminous display device (mini/micro LED display device) of the present embodiment. Sealing prevents reflection from metal wiring or the like, prevents color mixture between LED chips, and improves image contrast.

The colorant contained in the adhesive composition used in the second mode is the same as that described above for the first mode, and the average transmittance at a wavelength of 330 to 400 nm is greater than the average transmittance at a wavelength of 400 to 700 nm. things are preferred.

(crosslinking agent)
The second form of pressure-sensitive adhesive composition preferably contains a cross-linking agent capable of cross-linking with the above polymer. Specific examples of cross-linking agents for introducing a cross-linked structure into a polymer include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, oxazoline-based cross-linking agents, aziridine-based cross-linking agents, carbodiimide-based cross-linking agents, and metal chelate-based cross-linking agents. be done. Among these, isocyanate-based cross-linking agents and epoxy-based cross-linking agents are preferred because they are highly reactive with hydroxyl groups and carboxy groups of polymers and facilitate the introduction of a cross-linked structure. These cross-linking agents react with functional groups such as hydroxyl groups and carboxy groups introduced into the polymer to form cross-linked structures.

A polyisocyanate having two or more isocyanate groups in one molecule is used as the isocyanate-based cross-linking agent. Examples of isocyanate-based cross-linking agents include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; Aromatic isocyanates such as isocyanate, 4,4′-diphenylmethane diisocyanate, and xylylene diisocyanate; trimethylolpropane/tolylene diisocyanate trimer adduct (for example, “Coronate L” manufactured by Tosoh), trimethylolpropane/hexamethylene Diisocyanate trimer adduct (e.g., Tosoh "Coronate HL"), trimethylolpropane adduct of xylylene diisocyanate (e.g., Mitsui Chemicals "Takenate D110N", isocyanurate of hexamethylene diisocyanate (e.g., Tosoh " and isocyanate adducts such as "Coronate HX").

A polyfunctional epoxy compound having two or more epoxy groups in one molecule is used as the epoxy-based cross-linking agent. The epoxy group of the epoxy-based cross-linking agent may be a glycidyl group. Examples of epoxy-based cross-linking agents include N,N,N',N'-tetraglycidyl-m-xylenediamine, diglycidylaniline, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1, 6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, penta erythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipate diglycidyl ester, o-phthalate diglycidyl ester, triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether and the like. As the epoxy-based cross-linking agent, commercially available products such as "Denacol" manufactured by Nagase ChemteX, "Tetrad X" and "Tetrad C" manufactured by Mitsubishi Gas Chemical may be used.

The amount of the cross-linking agent is about 0.01 to 5 parts by weight with respect to 100 parts by weight of the polymer, and may be 0.05 parts by weight or more, 0.1 parts by weight or more, or 0.2 parts by weight or more. , 3 parts by weight or less, 2 parts by weight or less, or 1 part by weight or less.

(other ingredients)
In addition to the above components, the pressure-sensitive adhesive composition of the second form contains an oligomer, a tackifier, a silane coupling agent, a chain transfer agent, a plasticizer, a softening agent, an anti-degradation agent, a filler, an antioxidant, and a surfactant. agents, antistatic agents, and the like.

<Solvent type adhesive composition>
In this embodiment, the first pressure-sensitive adhesive layer 1 and the second pressure-sensitive adhesive layer 2 may be pressure-sensitive adhesive layers (third mode) formed from a solvent-type pressure-sensitive adhesive composition. The solvent-based pressure-sensitive adhesive composition contains at least a polymer and a solvent, and may contain a cross-linking agent. That is, the solvent-based pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer of the third mode contains a polymer, a solvent, and optionally a cross-linking agent.

[Third form]
The pressure-sensitive adhesive layer of the third form is formed by applying a solvent-based pressure-sensitive adhesive composition containing a polymer, a solvent, and optionally a cross-linking agent onto the release film and removing the solvent by drying. can do.

The solvent-based pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer of the third mode contains a polymer, a solvent, and optionally a cross-linking agent.

(polymer)
As the polymer contained in the solvent-based pressure-sensitive adhesive composition, various polymers can be applied as in the first embodiment, and an acrylic polymer is preferably used. The monomer components constituting the acrylic polymer are the same as in the first embodiment.

In the third embodiment, a polymer having a relatively large molecular weight is used as the polymer contained in the solvent-based pressure-sensitive adhesive composition in order to form a solid (regular) pressure-sensitive adhesive layer on the substrate. The weight average molecular weight of the polymer is, for example, about 100,000 to 2,000,000.

The acrylic polymer contained in the solvent-based pressure-sensitive adhesive composition of the third form may be a (meth)acrylic block copolymer. When the first pressure-sensitive adhesive layer 1 and / or the second pressure-sensitive adhesive layer 2 is formed from a solvent-based pressure-sensitive adhesive composition containing a (meth)acrylic block copolymer, it has excellent step absorption and processability. Since it is excellent, it is possible to seal the gaps without leaving air bubbles in the steps of the plurality of LED chips arranged on the substrate of the display panel. The problem of protrusion is less likely to occur.

In the present embodiment, the pressure-sensitive adhesive composition forming the first pressure-sensitive adhesive layer 1 is preferably a solvent-based pressure-sensitive adhesive composition containing a (meth)acrylic block copolymer. With this configuration, the first pressure-sensitive adhesive layer 1 is excellent in step absorption and workability, and air bubbles are formed on the steps of a plurality of LED chips, metal wiring, etc. arranged on the substrate of the display panel. Since it is possible to seal without leaving any gaps, it is possible to prevent color mixture between LED chips, improve image contrast, and efficiently prevent reflections due to metal wiring or the like.

In this embodiment, the (meth)acrylic block copolymer comprises a high Tg segment having a glass transition temperature of 0° C. or higher and 100° C. or lower and a low Tg segment having a glass transition temperature of −100° C. or higher and lower than 0° C. It is preferable to have a tan δ peak in the region above 0°C and in the region below 0°C.

In this specification, "high Tg segment having a glass transition temperature of 0 ° C. or more and 100 ° C. or less" is simply "high Tg segment", "low Tg segment having a glass transition temperature of -100 ° C. or more and less than 0 ° C." "Low Tg segment", the tan δ peak in the region above 0 ° C. is simply "high temperature region tan δ peak", the tan δ peak in the region below 0 ° C. is simply "low temperature region tan δ peak", the high Tg segment and the low Tg A (meth)acrylic block copolymer having a segment, the high temperature region tan δ peak and the low temperature region tan δ peak is "(meth)acrylic block copolymer A", and a solvent-based pressure-sensitive adhesive containing the (meth)acrylic block copolymer A The composition may be referred to as "solvent-based pressure-sensitive adhesive composition A".

The “segment” in the high Tg segment and the low Tg segment refers to a partial structure that constitutes each block unit of the (meth)acrylic block copolymer A.

The structure of the (meth)acrylic block copolymer A may be a linear block copolymer, a branched (star-shaped) block copolymer, or a mixture thereof. The structure of such a block copolymer may be appropriately selected according to the desired physical properties of the block copolymer, but from the viewpoint of cost and ease of production, a linear block copolymer is preferred. In addition, the linear block copolymer may have any structure (sequence), but from the viewpoint of the physical properties of the linear block copolymer or the physical properties of the solvent-based pressure-sensitive adhesive composition A, (AB) _n- type, It is preferably a block copolymer having at least one structure selected from the group consisting of (AB) _n -A type (where n is an integer of 1 or more, eg, an integer of 1 to 3). A and B in these structures refer to segments composed of different monomer compositions. In the present specification, the segment represented by A, which constitutes the linear block copolymer, may be referred to as "A segment", and the segment represented by B may be referred to as "B segment".

Among these, AB type diblock copolymer represented by AB and ABA type triblock copolymer represented by ABA are used from the viewpoint of ease of production, physical properties of solvent-based pressure-sensitive adhesive composition A, etc. Preferred, more preferred are ABA-type triblock copolymers. In the ABA type triblock copolymer, the cross-linked structure between the block copolymers becomes more advanced due to the pseudo cross-linking between the A segments at both ends, the cohesive force of the block copolymer is improved, and higher adhesion (adhesive force) is exhibited. can be considered. In addition, in the ABA-type triblock copolymer, the two A segments located at both ends may be the same or different.

When the (meth)acrylic block copolymer A is an ABA-type triblock copolymer, at least one of the two A segments and one B segment (three in total) is a high Tg segment and at least another one is a low Tg segment. A segment is fine. From the viewpoint of ease of production, physical properties of the solvent-based pressure-sensitive adhesive composition A, etc., an ABA triblock copolymer in which the A segment is the high Tg segment and the B segment is the low Tg segment is preferred. In that case, ABA-type triblock copolymers are preferred in which at least one of the two A segments is a high Tg segment and the B segment is a low Tg segment, both of the two A segments are high Tg segments and the B segment ABA-type triblock copolymers in which is the low Tg segment are more preferred.

The glass transition temperature (Tg) of the high Tg segment constituting the (meth)acrylic block copolymer A is 0° C. or higher and 100° C. or lower as described above. When the Tg of the high Tg segment is in this range, the storage elastic modulus of the solvent-based pressure-sensitive adhesive composition A at room temperature (25 ° C.) is highly controllable, and it is hard and excellent in workability, and in the region above 50 ° C. There is a tendency that the storage elastic modulus is remarkably lowered, resulting in a highly fluid PSA composition. From the viewpoint of improving the workability of the solvent-based PSA composition A at room temperature (25°C), the Tg of the high Tg segment is preferably 4°C or higher, more preferably 6°C or higher, and even more preferably 8°C or higher. 10°C or higher is even more preferred, and 12°C or higher is particularly preferred. On the other hand, from the viewpoint that the storage elastic modulus (G') of the solvent-based pressure-sensitive adhesive composition A decreases significantly in the region exceeding 50 ° C. and tends to become highly fluid, the Tg of the high Tg segment is 90 ° C. or less. It is preferably 85° C. or lower, more preferably 60° C. or lower, even more preferably 50° C. or lower, and particularly preferably 35° C. or lower.

The Tg of the low Tg segment constituting the (meth)acrylic block copolymer A is −100° C. or more and less than 0° C. as described above. When the glass Tg of the low Tg segment is in this range, only the low Tg segment is fluidized at room temperature (25 ° C.), and while ensuring workability, the solvent-based pressure-sensitive adhesive composition A has an appropriate adhesive strength. tend to be given. The Tg of the low Tg segment is preferably −95° C. or higher, more preferably −90° C. or higher, from the viewpoint that the storage elastic modulus of the solvent-type PSA composition A is unlikely to decrease at room temperature (25° C.) and the workability can be improved. It is preferably −80° C. or higher, more preferably -80° C. or higher. On the other hand, from the viewpoint of being able to improve the appropriate adhesive strength and workability of the solvent-based pressure-sensitive adhesive composition A at room temperature (25°C), the Tg of the low Tg segment is preferably -5°C or lower, more preferably -10°C or lower. -20°C or lower is more preferred, -30°C or lower is even more preferred, and -40°C or lower is particularly preferred.

The difference in Tg between the high Tg segment and the low Tg segment constituting the (meth)acrylic block copolymer A (Tg of the high Tg segment - Tg of the low Tg segment) is not particularly limited, but the solvent-based pressure-sensitive adhesive composition A The storage modulus at room temperature (25 ° C.) can be easily controlled to be high, and the storage modulus is significantly reduced in the region exceeding 50 ° C., resulting in a highly fluid PSA composition. Therefore, the temperature is preferably 30°C or higher, more preferably 35°C or higher, more preferably 40°C or higher, more preferably 45°C or higher, still more preferably 50°C or higher, particularly preferably 55°C or higher, and preferably 120°C or lower. , more preferably 115° C. or lower, more preferably 110° C. or lower, more preferably 105° C. or lower, still more preferably 100° C. or lower, and particularly preferably 95° C. or lower.

The glass transition temperatures (Tg) of the high Tg segment and the low Tg segment constituting the (meth)acrylic block copolymer A are calculated glass transition temperatures calculated from the following Fox formula. This calculated glass transition temperature is calculated based on the type and amount of each monomer component constituting the high Tg segment or low Tg segment of the (meth)acrylic block copolymer A. Therefore, the monomer component of each segment can be adjusted by selecting the type and amount of

The calculated glass transition temperature (calculated Tg) can be calculated from the following Fox formula [1].
1/calculated Tg=W1/Tg(1)+W2/Tg(2)+...+Wn/Tg(n) [1]
Here, W1, W2, . ), and Tg(1), Tg(2), ... Tg(n) are the glass transitions of homopolymers of monomer component (1), monomer component (2), ... monomer component (n) Temperature (unit is absolute temperature: K).
The glass transition temperatures of homopolymers are known from various literatures and catalogs, and are described, for example, in J. Brandup, EH Immergut, EA Grulke: Polymer Handbook: JOHNWILEY & SONS, INC. For monomers for which there are no numerical values in various documents, values measured by general thermal analysis such as differential thermal analysis and dynamic viscoelasticity measurement can be used.

The temperature range in which the high-temperature region tan δ peak of the (meth)acrylic block copolymer A appears is 0° C. or higher (for example, 0° C. or higher and 100° C. or lower) as described above. By having the high-temperature region tan δ peak in this temperature range, the storage elastic modulus at room temperature (25 ° C.) of the solvent-based pressure-sensitive adhesive composition A can be easily controlled to be high, and it is hard and excellent in processability, and in the region exceeding 50 ° C. There is a tendency that the storage elastic modulus is remarkably lowered, resulting in a highly fluid PSA composition. From the viewpoint of being able to improve the workability of the solvent-based pressure-sensitive adhesive composition A at room temperature (25°C), the temperature at which the high-temperature region tan δ peak appears is preferably 3°C or higher, more preferably 6°C or higher, and further preferably 9°C or higher. Preferably, 12° C. or higher is even more preferable, and 15° C. or higher is particularly preferable. On the other hand, from the viewpoint that the storage elastic modulus (G′) of the solvent-based pressure-sensitive adhesive composition A is likely to decrease significantly in the region above 50°C and the fluidity tends to be high, the temperature at which the tan δ peak appears in the high temperature region is 90°C. The following is preferable, 80° C. or lower is more preferable, 70° C. or lower is even more preferable, 65° C. or lower is even more preferable, and 60° C. or lower is particularly preferable.

The temperature range in which the low-temperature region tan δ peak of the (meth)acrylic block copolymer A appears is below 0° C. (for example, −100° C. or above and below 0° C.) as described above. Due to the fact that the low-temperature region tan δ peak is in this temperature range, only the low Tg segment is fluidized at room temperature (25° C.), and the solvent-based pressure-sensitive adhesive composition A is imparted with an appropriate adhesive force while ensuring workability. tend to be able to From the viewpoint that the storage elastic modulus of the solvent-based pressure-sensitive adhesive composition A is unlikely to decrease at room temperature (25°C) and the workability can be improved, the temperature at which the low-temperature region tan δ peak appears is preferably -95°C or higher, and -90°C. above is more preferred, -80°C or higher is even more preferred, and -70°C or higher is even more preferred. On the other hand, from the viewpoint of being able to improve the appropriate adhesive strength and workability of the solvent-based pressure-sensitive adhesive composition A at room temperature (25° C.), the temperature at which the tan δ peak appears in the low-temperature region is preferably −5° C. or less, and −10° C. or less. is more preferred, -20°C or lower is even more preferred, -30°C or lower is even more preferred, and -40°C or lower is particularly preferred.

Although the maximum value of the tan δ peak in the high temperature region is not particularly limited, it is preferably 0.5 to 3.0. When the maximum value of the tan δ peak in the high temperature region is within this range, the (meth)acrylic block copolymer A can achieve excellent workability and shape stability, which is preferable. The maximum value of the tan δ peak in the high temperature region is preferably 0.6 or more, more preferably 0.7 or more, in terms of achieving excellent workability. In addition, the maximum value of the tan δ peak in the high temperature region is preferably 2.5 or less, more preferably 2.2 or less, because dents are less likely to occur.

Although the maximum value of the tan δ peak in the low temperature region is not particularly limited, it is preferably 0.1 to 2.0. When the maximum value of the tan δ peak in the low temperature region is within this range, the (meth)acrylic block copolymer A can achieve excellent workability and shape stability, which is preferable. The maximum value of the tan δ peak in the high temperature region is preferably 0.2 or more, more preferably 0.3 or more, in terms of achieving excellent workability. In addition, the maximum value of the tan δ peak in the low temperature region is preferably 1.5 or less, more preferably 1 or less, because dents are less likely to occur.

The high-temperature region tan δ peak and the low-temperature region tan δ peak, and the temperature and maximum value at which they appear are measured by dynamic viscoelasticity measurement.

The (meth)acrylic block copolymer A is composed of multiple segments (including high Tg segments and low Tg segments) obtained by polymerizing monomer components, and the monomer components have (meth)acryloyl groups in the molecule. It contains a monomer (acrylic monomer) that has
The (meth)acrylic block copolymer A or each segment thereof preferably contains 70% by weight or more, more preferably 80% by weight or more of the acrylic monomer relative to the total amount (100% by weight) of the monomer component, and 90% by weight. % or more is particularly preferable.

Acrylic monomers constituting the (meth)acrylic block copolymer A or each segment thereof (including the high Tg segment and the low Tg segment) include an acrylic acid alkyl ester having a linear or branched alkyl group, and / Alternatively, it contains a monomer component derived from a methacrylic acid alkyl ester having a linear or branched alkyl group as the main monomer unit having the largest weight ratio.

As the (meth)acrylic acid alkyl ester having a linear or branched alkyl group for forming the segment of the (meth)acrylic block copolymer A, the (meth)acrylic acid having the above-mentioned chain alkyl group Specific examples of alkyl esters are given. As the (meth)acrylic acid alkyl ester for the segment, one type of (meth)acrylic acid alkyl ester may be used, or two or more types of (meth)acrylic acid alkyl ester may be used. As the (meth)acrylic acid alkyl esters for the segment, preferably methyl acrylate, n-butyl acrylate and 2-ethylhexyl acrylate, t-butyl acrylate, hexyl acrylate, heptyl acrylate, acrylic At least one selected from the group consisting of octyl acid and isononyl acrylate is used.

A segment of the (meth)acrylic block copolymer A may contain a monomer unit derived from an alicyclic monomer. Specific examples of the alicyclic monomer for forming the monomer unit of the segment include the (meth)acrylic acid alkyl ester having the alicyclic alkyl group described above. The alicyclic alkyl group may have a substituent. Examples of the substituent include halogen atoms (eg, fluorine atom, chlorine atom, bromine atom, iodine atom), straight-chain or branched-chain alkyl groups having 1 to 6 carbon atoms (eg, methyl group, ethyl group, n-propyl group, isopropyl group, etc.). The number of substituents is not particularly limited, and can be appropriately selected from 1 to 6. When there are two or more substituents, the two or more substituents may be the same or different. As the alicyclic monomer for the segment, one kind of alicyclic monomer may be used, or two or more kinds of alicyclic monomers may be used. The alicyclic monomer for the segment is preferably a cyclo having 4 to 10 carbon atoms which may have a substituent (eg, a linear or branched alkyl group having 1 to 6 carbon atoms). (Meth)acrylic acid cycloalkyl ester having an alkyl group, more preferably at least one selected from the group consisting of cyclohexyl acrylate and 3,3,5-trimethylcyclohexyl (meth)acrylate is used.

A segment of the (meth)acrylic block copolymer A may contain a monomer unit derived from a hydroxyl group-containing monomer. A hydroxyl group-containing monomer is a monomer having at least one hydroxyl group in the monomer unit. When the segment in the (meth)acrylic block copolymer A contains a hydroxyl group-containing monomer unit, the solvent-based pressure-sensitive adhesive composition A is likely to have adhesiveness and moderate cohesive strength.

As the hydroxyl group-containing monomer for forming the monomer unit of the segment, specific examples of the above hydroxyl group-containing monomers can be given. As the hydroxyl group-containing monomer for the segment, one type of hydroxyl group-containing monomer may be used, or two or more types of hydroxyl group-containing monomers may be used. Hydroxyl-containing monomers for the segment are preferably hydroxyl-containing (meth)acrylic acid esters, more preferably 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, methacrylic acid. At least one selected from the group consisting of 2-hydroxypropyl, 4-hydroxybutyl acrylate, and 4-hydroxybutyl methacrylate is used.

A segment of the (meth)acrylic block copolymer A may contain a monomer unit derived from a nitrogen atom-containing monomer. A nitrogen atom-containing monomer is a monomer that will have at least one nitrogen atom in the monomer unit. When the segment of the (meth)acrylic block copolymer A contains a nitrogen atom-containing monomer unit, the solvent-based pressure-sensitive adhesive composition A can easily obtain hardness and good adhesion reliability.

Specific examples of the nitrogen atom-containing monomer for forming the segment include the above nitrogen atom-containing monomers. As the nitrogen atom-containing monomer for the acrylic polymer, one kind of nitrogen atom-containing monomer may be used, or two or more kinds of nitrogen atom-containing monomers may be used. N-vinyl-2-pyrrolidone is preferably used as nitrogen atom-containing monomer for the segment.

A segment of the (meth)acrylic block copolymer A may contain a monomer unit derived from a carboxy group-containing monomer. A carboxy group-containing monomer is a monomer that will have at least one carboxy group in the monomer unit. When the segment of the (meth)acrylic block copolymer A contains a carboxy group-containing monomer unit, the solvent-based pressure-sensitive adhesive composition A may have good adhesion reliability.

Specific examples of the carboxy group-containing monomer for forming the monomer unit of the segment include the above carboxy group-containing monomers. As the carboxy group-containing monomer for the segment, one type of carboxy group-containing monomer may be used, or two or more types of carboxy group-containing monomers may be used. Acrylic acid is preferably used as the carboxy group-containing monomer for the segment.

Furthermore, monomer units for forming the segment include the above-mentioned other monomers. The content of other monomers in the monomer units constituting the segments of the (meth)acrylic block copolymer A is not particularly limited as long as it is 30% by weight or less with respect to the total amount of monomer components (100% by weight), and the present invention is appropriately selected within a range that does not impair the effect of

As a monomer component that constitutes the high Tg segment of the (meth)acrylic block copolymer A, it is said that the Tg of the high Tg segment can be easily controlled within a predetermined range, and the desired physical properties can be imparted to the (meth)acrylic block copolymer A. From the point of view, a (meth)acrylic acid alkyl ester having a linear alkyl group having 1 to 3 carbon atoms (hereinafter sometimes referred to as "(meth)acrylic acid C _1-3 linear alkyl ester" ), a (meth)acrylic acid alkyl ester having a branched alkyl group having 3 or 4 carbon atoms (hereinafter sometimes referred to as "(meth)acrylic acid C _3-4 branched chain alkyl ester") and at least one selected from the group consisting of alicyclic monomers. Homopolymers of these monomers have a relatively high Tg, so by containing a monomer selected from these as a monomer component constituting the high Tg segment, it is easy to control the Tg of the high Tg segment within the predetermined range of the present invention.

The alicyclic monomer has a cycloalkyl group having 4 to 10 carbon atoms which may have a substituent (eg, a linear or branched alkyl group having 1 to 6 carbon atoms) (meta ) Acrylic acid cycloalkyl ester is preferable, and acrylic having a cycloalkyl group having 4 to 10 carbon atoms which may have a substituent (eg, a linear or branched alkyl group having 1 to 6 carbon atoms) Acid cycloalkyl esters are more preferred, and cyclohexyl acrylate (Tg of homopolymer: 15°C) and 3,3,5-trimethylcyclohexyl (meth)acrylate (Tg of homopolymer: 52°C) are particularly preferred.

When an alicyclic monomer is contained as a monomer component constituting the high Tg segment, the content of the alicyclic monomer relative to the total amount of the monomer component (100% by weight) makes it easy to control the Tg of the high Tg segment within a predetermined range, From the viewpoint of imparting desired physical properties to the (meth)acrylic block copolymer A, it is preferably 10% by weight or more (eg, 10 to 100% by weight), more preferably 20% by weight or more, and more preferably 30% by weight or more. , more preferably 30% by weight or more, more preferably 40% by weight or more, more preferably 50% by weight or more, more preferably 60% by weight or more, more preferably 70% by weight or more, more preferably 80% by weight or more, more It is preferably 80% by weight or more, more preferably 90% by weight or more, and particularly preferably 95% by weight or more.

As the (meth)acrylic acid C _1-3 linear alkyl ester, acrylic acid C _1-3 linear alkyl ester is preferable, and methyl acrylate (Tg of homopolymer: 8° C.) is particularly preferable.
As the (meth)acrylic acid C _3-4 branched chain alkyl ester, acrylic acid C _3-4 branched chain alkyl ester is preferable, and t-butyl acrylate (Tg of homopolymer: 35° C.) is particularly preferable.

(Meth)acrylic acid _C1-3 straight-chain alkyl ester and/or (meth)acrylic acid _C3-4 branched-chain alkyl ester as the monomer component constituting the high Tg segment The content of the C _1-3 linear alkyl ester and/or C _3-4 branched alkyl (meth)acrylic acid relative to the total amount of the monomer component (100% by weight) is such that the Tg of the high Tg segment is within a predetermined range. From the viewpoint of being easy to control and being able to impart desired physical properties to the (meth)acrylic block copolymer A, it is preferably 10% by weight or more (for example, 10 to 100% by weight), more preferably 20% by weight or more, and more preferably 30% by weight or more, more preferably 30% by weight or more, more preferably 40% by weight or more, more preferably 50% by weight or more, more preferably 60% by weight or more, more preferably 70% by weight or more, more preferably 80% by weight % or more, more preferably 80% by weight or more, still more preferably 90% by weight or more, and particularly preferably 95% by weight or more.

As a monomer component that constitutes the low Tg segment of the (meth)acrylic block copolymer A, it is said that the Tg of the low Tg segment can be easily controlled within a predetermined range, and the desired physical properties can be imparted to the (meth)acrylic block copolymer A. From the point of view, a (meth)acrylic acid alkyl ester having a linear or branched alkyl group having 4 to 18 carbon atoms (hereinafter sometimes referred to as "(meth)acrylic acid C _4-18 alkyl ester" ) and hydroxyl group-containing monomers. That is, since a homopolymer of (meth)acrylic acid C _4-18 alkyl ester has a relatively low Tg, by containing this as a monomer component constituting the low Tg segment, the Tg of the low Tg segment is reduced to the specified value according to the present invention. easy to control in the range of On the other hand, the hydroxyl group-containing monomer also has a relatively low Tg, and furthermore, the (meth)acrylic block copolymer A can easily obtain adhesiveness and moderate cohesive strength. Therefore, it is more preferable that the (meth)acrylic block copolymer A contains both a (meth)acrylic acid C _4-18 alkyl ester and a hydroxyl group-containing monomer as the monomer component constituting the low Tg segment.

The (meth)acrylic acid C _4-18 alkyl ester is preferably an acrylate C _4-18 alkyl ester, such as butyl acrylate (Tg of homopolymer: −55° C.), 2-ethylhexyl acrylate (Tg of homopolymer: : -70°C), n-hexyl acrylate (Tg of homopolymer: -57°C), n-octyl acrylate (Tg of homopolymer: -65°C), isononyl acrylate (Tg of homopolymer: -58°C ) is particularly preferred.

When a (meth)acrylic acid _C4-18 alkyl ester is contained as a monomer component constituting the low Tg segment, the content of the (meth)acrylic acid _C4-18 alkyl ester relative to the total amount of the monomer components (100% by weight) is From the viewpoint that the Tg of the low Tg segment can be easily controlled within a predetermined range and the desired physical properties can be imparted to the (meth)acrylic block copolymer A, preferably 10% by weight or more (e.g., 10 to 100% by weight), more Preferably 20% by weight or more, more preferably 30% by weight or more, more preferably 30% by weight or more, more preferably 40% by weight or more, more preferably 50% by weight or more, more preferably 60% by weight or more, more preferably 70% by weight or more, more preferably 80% by weight or more, more preferably 80% by weight or more, still more preferably 90% by weight or more, and particularly preferably 95% by weight or more.

As the hydroxyl group-containing monomer, a hydroxyl group-containing (meth)acrylic acid alkyl ester is preferable, and 4-hydroxybutyl acrylate (Tg of homopolymer: -65°C), 2-hydroxyethyl acrylate (Tg of homopolymer: -15 °C) is particularly preferred.

When a hydroxyl group-containing monomer is contained as a monomer component constituting the low Tg segment, the content of the hydroxyl group-containing monomer with respect to the total amount of monomer components (100% by weight) makes it easy to control the Tg of the low Tg segment within a predetermined range, (meta ) From the viewpoint of imparting desired physical properties to the acrylic block copolymer A, it is preferably 1% by weight or more, more preferably 1.5% by weight or more, more preferably 2% by weight or more, and still more preferably 2.5% by weight. More preferably, it is 3% by weight or more. On the other hand, the content of the hydroxyl group-containing monomer relative to the total monomer component (100% by weight) is preferably 50% by weight or less, more preferably 40% by weight or less, more preferably 30% by weight or less, more preferably 20% by weight or less, More preferably 10% by weight or less, particularly preferably 5% by weight or less.

When both a (meth)acrylic acid C _4-18 alkyl ester and a hydroxyl group-containing monomer are contained as the monomer components constituting the low Tg segment of the (meth)acrylic block copolymer A, the hydroxyl group-containing monomer and the (meth)acrylic acid The ratio of the C _4-18 alkyl ester (hydroxyl group-containing monomer/(meth)acrylic acid C _4-18 alkyl ester) is not particularly limited, but the lower limit is preferably 1/99, more preferably 1.5/98. 5, more preferably 2/98, more preferably 2.5/97.5, particularly preferably 3/97, while the upper limit is 50/50, more preferably 40/60, more preferably 30/ 70, more preferably 20/80.

The (meth)acrylic block copolymer A can be produced by the living radical polymerization method of the monomer components described above. The living radical polymerization method maintains the simplicity and versatility of the conventional radical polymerization method. It is preferable in that it is easy to produce a polymer having a suitable composition.

In the living radical polymerization method, the high Tg segment may be produced first, and the high Tg segment may be polymerized with the monomer of the low Tg segment; may be polymerized.

When the (meth)acrylic block copolymer A is an ABA-type triblock copolymer, it is preferable, from the viewpoint of ease of production, to first produce the A segment and then polymerize the B segment monomer onto the A segment.

For the living radical polymerization method, any known method can be used without particular limitation. Depending on the method of stabilizing the polymerization growth terminal, a method using a transition metal catalyst (ATRP method); There are methods such as a method using a cleavage chain transfer agent (RAFT agent) (RAFT method); and a method using an organic tellurium compound (TERP method). Among these methods, it is preferable to use the RAFT method from the viewpoints of the diversity of monomers that can be used, the ease of molecular weight control, and the fact that metals do not remain in the solvent-based pressure-sensitive adhesive composition.

The RAFT method can use a known method without particular limitation. , Step 2 of adding and polymerizing a monomer component different from the monomer composition in Step 1 to the first segment obtained in Step 1 to add the second segment to the first segment (second RAFT polymerization). After the second RAFT polymerization, 3rd, 4th, .

The steps 1 and 2 can be carried out by known and commonly used methods, for example, solution polymerization method, emulsion polymerization method, bulk polymerization method, polymerization method by heat or active energy ray irradiation (thermal polymerization method, active energy ray polymerization method). Among them, the solution polymerization method is preferable in terms of transparency, water resistance, cost, and the like. In addition, it is preferable that the polymerization is carried out while avoiding contact with oxygen in order to suppress polymerization inhibition due to oxygen. For example, it is preferred to carry out the polymerization under a nitrogen atmosphere.

When the (meth)acrylic block copolymer A is an ABA triblock copolymer, it is preferable to prepare the A segment in step 1 and add the B segment to the obtained A segment in step 2. . In this case, the A segment is preferably a high Tg segment, and the B segment is preferably a low Tg segment.

As the RAFT agent, known agents can be used without particular limitation. For example, compounds represented by the following formula (1), formula (2), or formula (3) dithiocarbonate) is preferred.

In Formula (1), Formula (2), or Formula (3) [Formulas (1) to (3)], R ^1a and R ^1b are the same or different and represent a hydrogen atom, a hydrocarbon group, or a cyano group. show. R ^1c represents a hydrocarbon group optionally having a cyano group. Examples of the hydrocarbon groups for R ^1a , R ^1b and R ^1c include hydrocarbon groups having 1 to 20 carbon atoms (straight-chain, branched-chain, or cyclic saturated or unsaturated hydrocarbon groups, etc.). Among them, hydrocarbon groups having 1 to 12 carbon atoms are preferred. Specific examples of the hydrocarbon group include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, cyclohexyl group, dodecyl group, octadecyl group, and the like. linear, branched or cyclic alkyl groups having 1 to 12 carbon atoms; aryl groups having 6 to 12 carbon atoms such as phenyl groups; is mentioned. Examples of the hydrocarbon group having a cyano group as R ^1c include groups in which 1 to 3 hydrogen atoms of the above hydrocarbon group are substituted with a cyano group.

In formulas (1) to (3), R ² represents a hydrocarbon group or a group in which some of the hydrogen atoms of the hydrocarbon group are substituted with carboxyl groups (eg, carboxyalkyl group). Examples of the hydrocarbon group include hydrocarbon groups having 1 to 20 carbon atoms (linear, branched, or cyclic saturated or unsaturated hydrocarbon groups, etc.). Hydrocarbon groups are preferred. Specific examples of hydrocarbon groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, cyclohexyl group, dodecyl group, octadecyl group and the like. linear, branched or cyclic alkyl groups having 1 to 12 carbon atoms; and arylalkyl groups having 7 to 10 total carbon atoms such as benzyl group and phenethyl group.

In the RAFT method, the raw material monomer reacts to insert between the sulfur atom in the RAFT agent shown in formulas (1) to (3) and the methylene group adjacent to the sulfur atom, and polymerization proceeds.

Many of the RAFT agents are commercially available. Those that are not commercially available can be easily synthesized by known or commonly used methods. In the present invention, the RAFT agent can be used singly or in combination of two or more.

RAFT agents include trithiocarbonates such as dibenzyltrithiocarbonate and S-cyanomethyl-S-dodecyltrithiocarbonate; Dithioesters; O-ethyl-S-(1-phenylethyl) dithiocarbonate, O-ethyl-S-(2-propoxyethyl) dithiocarbonate, O-ethyl-S-(1-cyano-1-methylethyl) dithiocarbonates such as dithiocarbonates, etc. Among them, trithiocarbonates are preferred, trithiocarbonates having a left-right symmetrical structure in formula (1) are more preferred, and dibenzyltrithiocarbonate, bis{4 -[ethyl-(2-acetyloxyethyl)carbamoyl]benzyl}trithiocarbonate is preferred.

The step 1 can be performed by polymerizing the monomer components in the presence of the RAFT agent. The amount of the RAFT agent used in step 1 is usually 0.05 to 20 parts by weight, preferably 0.05 to 10 parts by weight, per 100 parts by weight of the total amount of the monomer components. With such an amount used, it is easy to control the reaction, and it is easy to control the weight average molecular weight of the resulting segment.
The step 2 can be carried out by adding a monomer component to the polymerization reaction mixture obtained in the step 1 and further polymerizing.

The RAFT method is preferably carried out in the presence of a polymerization initiator. Examples of the polymerization initiator include ordinary organic polymerization initiators, and specific examples include peroxides and azo compounds. Among these, azo compounds are preferred. One type of polymerization initiator can be used alone, or two or more types can be used.

Examples of peroxide polymerization initiators include benzoyl peroxide and tert-butyl permaleate.
Examples of azo compounds include 2,2'-azobisisobutyronitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2-cyclopropyl propionitrile), 2,2′-azobis(2,4-dimethylvaleronitrile), 2,2′-azobis(2-methylbutyronitrile), 1,1′-azobis(cyclohexane-1-carbonitrile) , 2-(carbamoyl azo) isobutyronitrile, 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, 2,2′-azobis(2-amidinopropane) dihydrochloride, 2,2′-azobis ( N,N'-dimethylene isobutylamidine), 2,2'-azobis(isobutyramide) dihydrate, 4,4'-azobis(4-cyanopentanoic acid), 2,2'-azobis(2-cyanopropanol), Dimethyl-2,2'-azobis(2-methylpropionate), 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide].

The amount of the polymerization initiator used is usually 0.001 to 2 parts by weight, preferably 0.002 to 1 part by weight, per 100 parts by weight of the total amount of the monomer components. With such a usage amount, it is easy to control the weight average molecular weight of the resulting segment.

The RAFT method may be a bulk polymerization that does not use a polymerization solvent, but preferably uses a polymerization solvent. Examples of the polymerization solvent include aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane and n-octane; cyclopentane, cyclohexane, cycloheptane, cyclo Alicyclic hydrocarbons such as octane; halogenated hydrocarbons such as chloroform, carbon tetrachloride, 1,2-dichloroethane, chlorobenzene; diethyl ether, diisopropyl ether, 1,2-dimethoxyethane, dibutyl ether, tetrahydrofuran, dioxane, anisole Ethers such as phenylethyl ether and diphenyl ether; esters such as ethyl acetate, propyl acetate, butyl acetate and methyl propionate; ketones such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone and cyclohexanone; N,N-dimethylformamide, N , N-dimethylacetamide and N-methylpyrrolidone; nitriles such as acetonitrile and benzonitrile; sulfoxides such as dimethylsulfoxide and sulfolane. One type of polymerization solvent can be used alone, or two or more types can be used.

The amount of the polymerization solvent to be used is not particularly limited. It is preferably 10 mL or less, more preferably 1 mL or less.

The reaction temperature in the RAFT method is usually 60-120° C., preferably 70-110° C., and is usually carried out in an inert gas atmosphere such as nitrogen gas. This reaction can be carried out under normal pressure, increased pressure or reduced pressure, and is usually carried out under normal pressure. The reaction time is usually 1 to 20 hours, preferably 2 to 14 hours.

The polymerization reaction conditions of the RAFT method described above can be applied to steps 1 and 2, respectively.

After the completion of the polymerization reaction, the intended (meth)acrylic block copolymer A can be separated from the resulting reaction mixture by removing the solvent used, residual monomers, etc. by ordinary separation and purification means.

When the high Tg segment or low Tg segment of the (meth)acrylic block copolymer A is prepared in step 1, the weight average molecular weight (Mw) of the high Tg segment or low Tg segment is not particularly limited, but preferably 10 ,000 to 1,000,000, more preferably 50,000 to 500,000, still more preferably 100,000 to 300,000. Having the Mw of the high Tg segment or the low Tg segment within this range is suitable for the effects of the present invention described above.
When the (meth)acrylic block copolymer A has two or more high Tg segments or two or more low Tg segments, the Mw is the sum of the Mw.

The weight average molecular weight (Mw) of the (meth)acrylic block copolymer A is not particularly limited, but is preferably 200,000 (200,000) or more, more preferably 300,000 to 5,000,000, and still more preferably is between 400,000 and 2,500,000. The Mw of the (meth)acrylic block copolymer A being within this range is suitable for the effects of the present invention described above.

The molecular weight distribution (Mw/Mn) of the (meth)acrylic block copolymer A is not particularly limited, but is preferably greater than 1, more preferably 1.5 or more, still more preferably 2 or more, and particularly preferably 2.5. It is 5 or more, preferably 5 or less, more preferably 4.5 or less, still more preferably 4 or less, and particularly preferably 3.5 or less.

The weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn) are measured by GPC method.

The content of the high Tg segment in the (meth)acrylic block copolymer A is preferably 10% by weight or more, more preferably 20% by weight or more, and still more preferably 100% by weight of the total (meth)acrylic block copolymer A. It is 25% by weight or more, particularly preferably 30% by weight or more, preferably 95% by weight or less, more preferably 90% by weight or less, and still more preferably 85% by weight or less.

The content of the low Tg segment in the (meth)acrylic block copolymer A is preferably 5% by weight or more, more preferably 10% by weight or more, and still more preferably 100% by weight of the total (meth)acrylic block copolymer A. It is 15% by weight or more, preferably 60% by weight or less, more preferably 50% by weight or less, still more preferably 40% by weight or less, and particularly preferably 30% by weight or less.

The content of each segment and their ratio can be calculated from the weight average molecular weight (Mw) of each segment or (meth)acrylic block copolymer A obtained in each step of the RAFT method, and when forming each segment It can be controlled by the charging ratio of the monomers, the polymerization rate of each monomer, and the like.

The content of the (meth)acrylic block copolymer A in the solvent-based pressure-sensitive adhesive composition A is not particularly limited, but excellent processability at room temperature (25 ° C.) and excellent step absorbability in the region exceeding 50 ° C. from the viewpoint of obtaining the solvent type pressure-sensitive adhesive composition A total amount (total weight, 100% by weight), preferably 50% by weight or more (for example, 50 to 100% by weight), more preferably 60% by weight Above, more preferably 80% by weight or more, particularly preferably 90% by weight or more.

(solvent)
Since the polymer in the third form is solid, the solvent-based pressure-sensitive adhesive composition is a solution in which the polymer is dissolved in an organic solvent. For example, a polymer solution is obtained by solution polymerization of the monomer components. A polymer solution may be prepared by dissolving a solid polymer in an organic solvent.

Ethyl acetate, toluene and the like are generally used as the solvent. The solution concentration is usually about 20 to 80% by weight.

Polymerization initiators for solution polymerization of monomer components include azo initiators, peroxide initiators, redox initiators combining peroxides and reducing agents (for example, persulfate and sodium hydrogen sulfite combination, combination of peroxide and sodium ascorbate) and the like are preferably used. The amount of the polymerization initiator used is not particularly limited, but for example, it is preferably about 0.005 to 5 parts by weight, more preferably about 0.02 to 3 parts by weight, relative to 100 parts by weight of the total amount of the monomer components forming the polymer. preferable.

(coloring agent)
The solvent-based pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer of the third mode may contain a colorant. In particular, it is preferable that the solvent pressure-sensitive adhesive composition forming the first pressure-sensitive adhesive layer 1 further contains a colorant. When the solvent-based pressure-sensitive adhesive composition forming the first pressure-sensitive adhesive layer 1 contains a colorant, the transparency of the first pressure-sensitive adhesive layer 1 to visible light is reduced, and the T ₁ and T ₂ are reduced to T ₁ <T ₂ is preferably satisfied. The first pressure-sensitive adhesive layer 1, which has reduced permeability to visible light and is imparted with a light-shielding property, is provided between the metal wiring layer 6 and the LED chip of the self-luminous display device (mini/micro LED display device) of the present embodiment. Sealing prevents reflection from metal wiring or the like, prevents color mixture between LED chips, and improves image contrast.

The colorant may be either a dye or a pigment as long as it can be dissolved or dispersed in the solvent-based pressure-sensitive adhesive composition. Dyes are preferred because they can achieve a low haze even when added in small amounts, and are easy to distribute uniformly without sedimentation like pigments. Pigments are also preferred because they have high color development even when added in small amounts. If a pigment is used as the colorant, it preferably has low or no conductivity. Moreover, when a dye is used, it is preferable to use it together with an antioxidant or the like.

Colorants contained in the solvent-based pressure-sensitive adhesive composition in the third embodiment include ultraviolet-absorbing colorants in addition to the ultraviolet-transmitting colorants described above for the first embodiment.

Examples of ultraviolet-transmitting black pigments include "9050BLACK" and "UVBK-0001" manufactured by Tokushiki. Examples of ultraviolet-absorbing black dyes include "VALIFAST BLACK 3810" and "NUBIAN Black PA-2802" manufactured by Orient Chemical Industries. Examples of ultraviolet absorbing black pigments include carbon black and titanium black.

The content of the colorant in the solvent-based pressure-sensitive adhesive composition is, for example, about 0.01 to 20 parts by weight with respect to 100 parts by weight of the total amount of the monomer, and the type of the colorant, the color tone of the pressure-sensitive adhesive layer, and the light transmission It may be appropriately set according to the rate and the like. Colorants may be added to the composition as a solution or dispersion dissolved or dispersed in a suitable solvent.

(crosslinking agent)
The solvent-based pressure-sensitive adhesive composition of the third form may contain a cross-linking agent capable of cross-linking with the above polymer. In addition, when the solvent-based pressure-sensitive adhesive composition contains a (meth)acrylic block copolymer, the pressure-sensitive adhesive layer of the third form has sufficient shape stability and thus does not need to contain a cross-linking agent.

When the solvent-based pressure-sensitive adhesive composition contains a cross-linking agent in the third mode, the cross-linking agent is the same as that described above for the second mode, and is preferably an isocyanate-based cross-linking agent or an epoxy-based cross-linking agent.

In the third embodiment, when the solvent-based pressure-sensitive adhesive composition contains a cross-linking agent, the content thereof is about 0.01 to 5 parts by weight, 0.05 parts by weight or more, and 0.05 part by weight or more, based on 100 parts by weight of the polymer. It may be 1 part by weight or more, or 0.2 parts by weight or more, and may be 3 parts by weight or less, 2 parts by weight or less, or 1 part by weight or less.

(other ingredients)
The solvent-based pressure-sensitive adhesive composition of the third form includes, in addition to the above components, an oligomer, a tackifier, a silane coupling agent, a chain transfer agent, a plasticizer, a softening agent, a deterioration inhibitor, a filler, an antioxidant, Surfactants, antistatic agents, etc. may be included.

<Optical laminate>
In the present embodiment, the optical laminates 10 to 12 can be prepared by laminating the second adhesive layer 2 and further laminating the first adhesive layer 1 on the surface 3b of the substrate 3.

[First form]
The method of laminating the second pressure-sensitive adhesive layer 2 of the first form on the surface 3b of the base material 3 is not particularly limited. It can be carried out by molding and photocuring to produce a sheet-like second pressure-sensitive adhesive layer 2 and then laminating it on the surface 3b of the substrate 3 .

The method for further laminating the first pressure-sensitive adhesive layer 1 on the second pressure-sensitive adhesive layer 2 laminated on the substrate 3 is not particularly limited. It can be carried out by forming it into a sheet by pressing, photocuring to produce a sheet-like first adhesive layer 1, and then bonding it to the second adhesive layer laminated on the surface 3b of the base material 3. can.

The photocurable adhesive composition is applied in a sheet form (layered form) on the release film, and the coating film of the adhesive composition on the release film is irradiated with ultraviolet rays to perform photocuring, thereby obtaining the first form. A first adhesive layer or a second adhesive layer is obtained. When performing photocuring, a release film is further attached to the surface of the coating film, and the photocurable pressure-sensitive adhesive composition is sandwiched between the two release films and irradiated with ultraviolet rays to prevent polymerization inhibition due to oxygen. Prevention is preferred. Prior to photocuring, the sheet-like coating film may be heated for the purpose of removing the solvent or dispersion medium of the colorant. If the solvent or the like is removed by heating, it is preferably carried out before attaching the release film.

Films made of various resin materials are used as the film substrate of the release film. Examples of resin materials include polyester-based resins such as polyethylene terephthalate and polyethylene naphthalate, acetate-based resins, polyethersulfone-based resins, polycarbonate-based resins, polyamide-based resins, polyimide-based resins, polyolefin-based resins, (meth)acrylic-based resins, Polyvinyl chloride-based resins, polyvinylidene chloride-based resins, polystyrene-based resins, polyvinyl alcohol-based resins, polyarylate-based resins, polyphenylene sulfide-based resins, and the like are included. Among these, polyester resins such as polyethylene terephthalate are particularly preferred. The thickness of the film substrate is preferably 10-200 μm, more preferably 25-150 μm. Materials for the release layer include silicone-based release agents, fluorine-based release agents, long-chain alkyl-based release agents, fatty acid amide-based release agents, and the like. The thickness of the release layer is generally about 10 to 2000 nm.

Methods for applying the adhesive composition onto the release film include roll coating, kiss roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, air knife coating, and curtain coating. , lip coat, die coater and the like are used.

The thickness of the first adhesive layer 1 is not particularly limited, and while sufficiently sealing the light emitting elements arranged on the display panel described later, the upper portion (image display side) of the light emitting elements is the second adhesive layer 2. It may be appropriately set so as to be covered. For example, the thickness of the first adhesive layer is 0.1 to 2.0 times, preferably 0.2 to 1.5 times, more preferably 0.3 to 1.2 times the height of the light emitting element. adjusted to be Specifically, the thickness of the first adhesive layer is, for example, about 10 to 300 μm, preferably 15 to 200 μm. Specifically, the thickness of the first adhesive layer may be 10 µm or more, 15 µm or more, 20 µm or more, 30 µm or more, 40 µm or more, or 50 µm or more. Further, when the first pressure-sensitive adhesive layer contains an ultraviolet-transmitting colorant, even when the thickness of the first pressure-sensitive adhesive layer is large, the photocurable pressure-sensitive adhesive composition can be uniformly photocured in the thickness direction. is. The thickness of the first adhesive layer may be 300 μm or less, 250 μm or less, or 200 μm or less.

The thickness of the second pressure-sensitive adhesive layer 2 is not particularly limited. can be set as appropriate. Specifically, the thickness of the second adhesive layer is, for example, about 1 to 500 μm, more preferably 10 to 300 μm, even more preferably 15 to 200 μm. Specifically, the thickness of the second adhesive layer may be 1 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, 30 μm or more, 40 μm or more, or 50 μm or more. Moreover, the thickness of the second adhesive layer may be 400 μm or less, 300 μm or less, 250 μm or less, or 200 μm or less.

The total thickness of the first pressure-sensitive adhesive layer 1 and the second pressure-sensitive adhesive layer 2 is not particularly limited. It should be set as appropriate. For example, the thickness of the adhesive layer is 1.0 to 4.0 times, preferably 1.1 to 3.0 times, more preferably 1.2 to 2.5 times, more preferably 1.2 to 2.5 times the height of the light emitting element. is adjusted to be 1.3 to 2.0 times. Specifically, the total thickness of the first adhesive layer 1 and the second adhesive layer 2 is, for example, about 11 to 800 μm, and may be 20 μm or more, 30 μm or more, 40 μm or more, or 50 μm or more. Also, the total thickness of the first adhesive layer 1 and the second adhesive layer 2 may be, for example, 700 μm or less, 600 μm or less, 500 μm or less, or 400 μm or less.

The ratio of the thickness of the second pressure-sensitive adhesive layer to the thickness of the first pressure-sensitive adhesive layer (thickness of the second pressure-sensitive adhesive layer/thickness of the first pressure-sensitive adhesive layer) is not particularly limited, and is arranged on a display panel described later. It may be appropriately set so that the upper portion (image display side) of the light emitting element is covered with the second pressure-sensitive adhesive layer while sufficiently sealing the light emitting element. Specifically, (thickness of the second pressure-sensitive adhesive layer/thickness of the first pressure-sensitive adhesive layer) is, for example, about 1.0 to 5.0, preferably 1.2 to 4.0, more preferably It may be from 1.3 to 3.0.

By irradiating the photocurable pressure-sensitive adhesive composition applied in layers on the release film with ultraviolet rays, active species are generated from the photopolymerization initiator, the photopolymerizable compound is polymerized, and the polymerization rate increases (unreacted As the amount of the monomer decreases, the liquid photocurable pressure-sensitive adhesive composition becomes a solid (regular) pressure-sensitive adhesive layer. The light source for ultraviolet irradiation is not particularly limited as long as it can irradiate light in the wavelength range to which the photopolymerization initiator contained in the photocurable pressure-sensitive adhesive composition is sensitive. Ultra-high pressure mercury lamps, metal halide lamps, xenon lamps, etc. are used.

The integrated light quantity of the irradiation light is, for example, about 100 to 5000 mJ/cm ² . The polymerization rate (non-volatile content) of the adhesive layer composed of the photocured product of the photocurable adhesive composition is preferably 80% or higher, more preferably 85% or higher, and even more preferably 90% or higher. The polymerization rate may be 93% or more or 95% or more. In order to reduce the non-volatile content, the pressure-sensitive adhesive layer may be heated to remove volatile content such as residual monomers, unreacted polymerization initiators and solvents.

When release films are provided on both sides of the pressure-sensitive adhesive layer, the thickness of one release film and the thickness of the other release film may be the same or different. The release force when peeling off the release film temporarily attached to one side of the adhesive layer and the peeling force when peeling off the release film temporarily attached to the other side of the adhesive layer are different even if they are the same. may When the two have different peel strengths, the peel film (light peel film) having relatively smaller peel strength is first peeled from the second pressure-sensitive adhesive layer 2 and laminated to the surface 3b of the base material 3, and then A release film (heavy release film) having a relatively large release force is peeled off from the second pressure-sensitive adhesive layer 2 to expose the second pressure-sensitive adhesive layer. After that, the light release film is peeled off from the first pressure-sensitive adhesive layer 1 and attached to the exposed second pressure-sensitive adhesive layer, thereby forming an optical film having the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer of the first form. Laminates can be made.

Further, after applying the photocurable adhesive composition to the surface 3b of the substrate 3 and forming it into a sheet, a release film is attached to the surface of the coating film, and ultraviolet rays are irradiated. An optical laminate having the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer of the first form can also be produced in the same manner as described above, except that the second adhesive layer is laminated on the second adhesive layer.

When the first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer contains a coloring agent, it absorbs visible light. The visible light transmittance of the optical laminate of the first embodiment is, for example, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less. % or less.

In the first form, the visible light transmittance T ₁ of the first adhesive layer is not particularly limited, but is, for example, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, or 30% or less. , 20% or less, or 10% or less. When the visible light transmittance T ₁ of the first pressure-sensitive adhesive layer is 80% or less, it becomes easier to make the transmittance lower than the visible light transmittance T ₂ of the second pressure-sensitive adhesive layer. By sealing between the metal wiring and the light-emitting element of the light-emitting display device, it is possible to prevent reflection of the metal wiring and the like, prevent color mixing between the light-emitting elements, and improve the contrast. Further, as described above, when the first adhesive layer uses a coloring agent that absorbs ultraviolet rays less than the absorption of visible light, the first adhesive layer has an average transmittance T _UV at a wavelength of 330 to 400 nm. It is larger than the average transmittance T _VIS between 400 and 700 nm. The average transmittance T _VIS of the first pressure-sensitive adhesive layer at a wavelength of 400 to 700 nm is, for example, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, or 10 % or less. The average transmittance T _UV of the first adhesive layer at a wavelength of 330 to 400 nm is preferably 5% or more, and may be 10% or more, 15% or more, 20% or more, or 25% or more. The difference T _UV -T _VIS between T _UV and T _VIS may be 3% or more, 5% or more, 8% or more, or 10% or more.

In the first form, the visible light transmittance T ₂ of the second adhesive layer is not particularly limited, but is, for example, 85 to 100%, and may be 88% or more, 90% or more, or 92% or more. As described above, the luminous efficiency is improved by covering the upper portion (on the image display side) of the light emitting element of the self-luminous display device with the second pressure-sensitive adhesive layer having high transparency.

In the first embodiment, the shear storage elastic modulus G′25° C. of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer at a temperature of 25° C. is, for example, about 10 to 1000 kPa, 30 kPa or more, 50 kPa or more, 70 kPa or more, or 100 kPa or more. or 700 kPa or less, 500 kPa or less, 300 kPa or less, or 200 kPa or less. The shear storage modulus G′85° C. of the adhesive layer at a temperature of 85° C. is, for example, about 3 to 300 kPa, and may be 5 kPa or more, 7 kPa or more, or 10 kPa or more, and 200 kPa or less, 150 kPa or less, or 100 kPa. It may be below. If the shear storage elastic modulus of the pressure-sensitive adhesive layer is within the above range, both moderate flexibility and adhesiveness can be achieved. The shear storage modulus is a value measured by dynamic viscoelasticity measurement at a frequency of 1 Hz.

[Second form]
An optical laminate having a second type of pressure-sensitive adhesive layer is obtained by coating a release film with the second type of photocurable pressure-sensitive adhesive composition, and optionally removing the solvent by drying to form a second pressure-sensitive adhesive layer. is formed and attached to the surface 3 b of the base material 3 . Next, the second form of photocurable adhesive composition is applied to the release film, and if necessary, the solvent is dried and removed to form a first adhesive layer. On the surface 3b of the substrate 3 It can be prepared by attaching to the second pressure-sensitive adhesive layer laminated on.

The optical layered body having the adhesive layer of the second type is obtained by applying the photocurable adhesive composition of the second type onto the surface 3b of the substrate 3, and removing the solvent by drying if necessary. to form the second adhesive layer. Next, the second form of photocurable adhesive composition is applied to the release film, and if necessary, the solvent is dried and removed to form a first adhesive layer. On the surface 3b of the substrate 3 It can also be prepared by sticking to the second pressure-sensitive adhesive layer laminated on.

When the photocurable pressure-sensitive adhesive composition contains a solvent, it is preferable to dry the solvent after applying the pressure-sensitive adhesive composition. As a drying method, an appropriate method can be adopted depending on the purpose. The drying temperature is preferably 40°C to 200°C, more preferably 50°C to 180°C, and particularly preferably 70°C to 170°C. An appropriate drying time can be adopted as appropriate. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 15 minutes, particularly preferably 10 seconds to 10 minutes.

After applying the photocurable pressure-sensitive adhesive composition, heating is performed as necessary to introduce a crosslinked structure into the polymer. The heating temperature and heating time may be appropriately set according to the type of cross-linking agent used, and are usually in the range of 20° C. to 160° C. for about 1 minute to 7 days. Heating for drying the solvent may serve as heating for cross-linking. Introduction of the crosslinked structure does not necessarily have to be accompanied by heating.

The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer of the second form have the same thicknesses as the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer of the first form, respectively (the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer each thickness, total thickness, thickness ratio), light transmittance, and shear storage elastic modulus. Since the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer of the second form are not photocured, the photopolymerizable compound is contained in an unreacted state. That is, the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer of the second form are a photocurable pressure-sensitive adhesive containing a polymer, a photopolymerizable compound, a photopolymerization initiator, and optionally a colorant. layer.

The optical laminate having the photocurable first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer of the second form is photocured by irradiating with ultraviolet light after being attached to a display panel described later. can be done. Photocuring can change the adhesive force between the optical layered body and the display panel. For example, since the adhesive layer before photocuring is highly flexible, it is possible to fill uneven shapes and steps formed by light-emitting elements arranged on the display panel. and adhesion reliability can be improved.

Ultraviolet rays are used as actinic rays for photo-curing the pressure-sensitive adhesive layer. As with the adhesive layer of the first form, when an ultraviolet-transmitting colorant is used, the transmittance of ultraviolet light is greater than that of visible light, so even if the thickness of the adhesive layer is large, the light curing time is reduced. Curing inhibition can be suppressed.

The optical layered body having the first and/or second pressure-sensitive adhesive layers of the first type and the second type containing the above ultraviolet-transmitting colorant absorbs visible light. It is desirable that the optical layered bodies of the first type and the second type have a maximum value of transmittance at 350 nm to 450 nm.

The visible light transmittance of the optical layered body of the first form and the second form is, for example, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less. % or less or 5% or less.

[Third form]
An optical laminate having a third type of pressure-sensitive adhesive layer is obtained by applying the third type of solvent-based pressure-sensitive adhesive composition to a release film, and optionally removing the solvent by drying to form a second pressure-sensitive adhesive layer. Then, the surface 3b of the substrate 3 is adhered. Next, the third form of the solvent-based pressure-sensitive adhesive composition is applied to the release film, and if necessary, the solvent is removed by drying to form a first pressure-sensitive adhesive layer. It can be prepared by affixing to the laminated second pressure-sensitive adhesive layer.

The optical layered body having the adhesive layer of the third type can be obtained by applying the solvent-based adhesive composition of the third type onto the surface 3b of the substrate 3, and removing the solvent by drying if necessary. , to form a second adhesive layer. Next, the third form of the solvent-based pressure-sensitive adhesive composition is applied to the release film, and if necessary, the solvent is removed by drying to form a first pressure-sensitive adhesive layer. It can also be prepared by attaching to the laminated second pressure-sensitive adhesive layer.

After applying the solvent-based pressure-sensitive adhesive composition, the solvent is dried. As a drying method, an appropriate method can be adopted depending on the purpose. The drying temperature is preferably 40°C to 200°C, more preferably 50°C to 180°C, and particularly preferably 70°C to 170°C. An appropriate drying time can be adopted as appropriate. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 15 minutes, particularly preferably 10 seconds to 10 minutes.

After applying the solvent-based pressure-sensitive adhesive composition, heating may be performed as necessary. The heating temperature and heating time may be appropriately set according to the type of cross-linking agent used, and are usually in the range of 20° C. to 160° C. for about 1 minute to 7 days.

The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer of the third form have the same thickness as the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer of the first form, respectively (the thickness of the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer Each thickness, total thickness, thickness ratio), light transmittance, and shear storage elastic modulus.

In addition, the storage elastic modulus at 25 ° C. of the first pressure-sensitive adhesive layer and / or the second pressure-sensitive adhesive layer (especially the first pressure-sensitive adhesive layer) when the solvent-based pressure-sensitive adhesive composition contains the (meth)acrylic block copolymer A (G'25) is not particularly limited, but from the viewpoint of improving workability at room temperature, it is preferably 1 MPa or more, more preferably 1.5 MPa or more, more preferably 2 MPa or more, more preferably 2.5 MPa or more. It is preferably 3 MPa or more, and from the viewpoint of improving adhesion reliability at room temperature, it is preferably 50 MPa or less, more preferably 45 MPa or less, more preferably 40 MPa or less, more preferably 35 MPa or less, and more preferably 30 MPa or less.

The storage elastic modulus (G '50) is not particularly limited, but is preferably 0.5 MPa or less, more preferably 0.45 MPa or less, more preferably 0.4 MPa or less, from the viewpoint of improving the step absorbability in the region exceeding 50 ° C. is 0.35 MPa or more, more preferably 0.3 MPa or less, and from the viewpoint of improving the handleability in the region exceeding 50° C., it is preferably 0.0001 MPa or more, more preferably 0.0005 MPa or more, and more preferably 0.001 MPa or more. 001 MPa or more, more preferably 0.005 MPa or more, more preferably 0.01 MPa or more.

The storage elastic modulus at 25 ° C. of the first pressure-sensitive adhesive layer and / or the second pressure-sensitive adhesive layer (especially the first pressure-sensitive adhesive layer) when the solvent-based pressure-sensitive adhesive composition contains the (meth)acrylic block copolymer A and 50 The storage modulus ratio (G'25/G'50) at °C is not particularly limited, but from the viewpoint of improving workability at room temperature and improving step absorbability in the region exceeding 50 °C, it is 3 or more. It is preferably 5 or more, more preferably 10 or more, still more preferably 15 or more, particularly preferably 20 or more, and from the viewpoint of adhesion reliability, handleability, etc., preferably 100 or less, more preferably 95 or less, It is more preferably 90 or less, still more preferably 85 or less, and particularly preferably 80 or less.

The storage elastic modulus (G'25) at 25°C and the storage elastic modulus (G'25) at 50°C, and their ratio (G'25/G'50) are measured by dynamic viscoelasticity measurement. It is what is done.

The optical layered body having the first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer of the third type containing a colorant absorbs visible light.

The visible light transmittance of the optical laminate of the third embodiment is, for example, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less. % or less.

The optical layered body of this embodiment (first to third embodiments) may be provided with a release film on the first pressure-sensitive adhesive layer until use. Further, in the optical layered body of the present embodiment (first to third embodiments), a surface protection film may be laminated on the surface 3a of the substrate 3. The surface protective film is suitable for preventing the adhesion of scratches and stains during the manufacture, transportation and shipment of the optical laminate and optical products containing the optical laminate.

In addition to the first adhesive layer 1, the second adhesive layer 2, the substrate 3, the release film, and the surface protection film, the optical laminate of the present embodiment (first to third embodiments) has the effects of the present invention. other layers, for example, a substrate other than the substrate 3, the first adhesive layer 1, an adhesive layer other than the second adhesive layer 2, an intermediate layer, an undercoat layer, etc., on the surface or arbitrarily It may have between the layers.

<Self-luminous display device>
A self-luminous display device according to a second aspect of the present invention is provided by arranging a large number of very small light-emitting elements on a wiring board and selectively causing each light-emitting element to emit light by means of light emission control means connected thereto. , visual information such as characters, images, moving images, etc., can be directly displayed on the display screen by blinking of each light emitting element. Examples of self-luminous display devices include mini/micro LED display devices and organic EL (electroluminescence) display devices. The optical laminate according to the first aspect of the present invention is particularly suitable for manufacturing mini/micro LED display devices.

4 to 6 are schematic diagrams (cross-sectional views) showing an embodiment of a self-luminous display device (mini/micro LED display device) according to the second aspect of the present invention. A mini/micro LED display device 20 according to this embodiment includes a display panel in which a plurality of LEDs 7 are arranged on one side of a substrate 5 and an optical laminate 10 . The surface of the display panel on which the LED chips 7 are arranged and the first adhesive layer 1 of the optical laminate 10 are laminated. In the mini/micro LED display device 21, the surface 3a of the substrate 3 on which the second adhesive layer 2 is not laminated is subjected to antireflection treatment and/or antiglare treatment 4. FIG. In the mini/micro LED display device 22, an antiglare layer 4a is formed as an antiglare treatment on the surface 3a of the substrate 3 on which the second adhesive layer 2 is not laminated.

In this embodiment, a metal wiring layer 6 for sending light emission control signals to each LED chip 7 is laminated on the substrate 5 of the display panel. LED chips 7 that emit red (R), green (G), and blue (B) lights are alternately arranged on a substrate 5 of the display panel via metal wiring layers 6 . The metal wiring layer 6 is made of metal such as copper, and reflects the light emitted from each LED chip 7 to reduce the visibility of the image. In addition, the lights emitted from the LED chips 7 of each color of RGB are mixed, and the contrast is lowered.

In the mini/micro LED display device of this embodiment, the first adhesive layer 1 seals between the LED chips 7 arranged on the display panel and the metal wiring layer 6 . Since the visible light transmittance of the first pressure-sensitive adhesive layer 1 is lower than the visible light transmittance of the second pressure-sensitive adhesive layer 2, it has sufficient light shielding properties in the visible light region. Since the first pressure-sensitive adhesive layer 1 having a higher light-shielding property (lower transparency) seals the space between the LED chips 7 without gaps, it is possible to prevent color mixing between the LED chips 7 and improve the contrast. can be done. In addition, since the first pressure-sensitive adhesive layer 1 having a higher light-shielding property (lower transparency) also seals the surface of the metal wiring layer 6 , reflection by the metal wiring layer 6 can be prevented.

In this embodiment, the second pressure-sensitive adhesive layer 2 seals the upper portion (display image side) of each LED chip 7 arranged on the display panel. Since the visible light transmittance of the second pressure-sensitive adhesive layer 2 is higher than the visible light transmittance of the first pressure-sensitive adhesive layer 1, it has sufficient transparency in the visible light region. Since the second adhesive layer 2 with higher transparency seals the upper portion (on the display image side) of each LED chip 7, the absorption of visible light emitted from each LED chip 7 is suppressed low, and the luminous efficiency is improved. can be made higher, thus making the image brighter. In addition, since it is not necessary to raise the output to increase the emission luminance, the power consumption can be kept low.

As described above, since the optical layered body according to the present embodiment includes the first pressure-sensitive adhesive layer having a higher light-shielding property (lower permeability), when a metal adherend is laminated on the first pressure-sensitive adhesive layer, Even so, reflection and gloss on the metal surface can be prevented. When a metal adherend is laminated on the first pressure-sensitive adhesive layer of the optical laminate of the present embodiment, the reflectance in the visible light range of 5° specular reflection on the substrate surface 3a is preferably 50% or less. , is more preferably 30% or less, further preferably 15% or less, and particularly preferably 10% or less. The glossiness (based on JIS Z 8741-1997) of the substrate surface 3a when the metal adherend is laminated on the first adhesive layer of the optical laminate of the present embodiment is preferably 100% or less. , is more preferably 80% or less, even more preferably 60% or less, and particularly preferably 50% or less.
As the metal adherend, copper, aluminum, stainless steel, or the like can be used.

Further, in the mini/micro LED display device of the present embodiment, when the surface 3a of the substrate 3 is subjected to antireflection treatment and/or antiglare treatment 4, reflection of external light and image reflection on the substrate surface 3a Visibility is prevented from being lowered due to inclusions, etc., or appearance such as glossiness is adjusted. In the mini/micro LED display device 22 according to this embodiment, the antiglare layer 4a is formed on the surface 3a of the substrate 3. As shown in FIG. The average inclination angle θa (°) of the antiglare layer 4a of the mini/micro LED display device 22 according to this embodiment is the same as above.

The self-luminous display device of this embodiment may include optical members other than the display panel and the optical laminate. Examples of the optical member include, but are not particularly limited to, a polarizing plate, a retardation plate, an antireflection film, a viewing angle adjusting film, and an optical compensation film. The optical member also includes members (design film, decorative film, surface protective plate, etc.) that play a role of decoration and protection while maintaining the visibility of the display device and the input device.

The mini/micro LED display device of this embodiment is obtained by bonding a display panel in which a plurality of LED chips are arranged on one side of a substrate and a first pressure-sensitive adhesive layer of the optical laminate according to the first aspect of the present invention. It can be manufactured by manufacturing more.

Specifically, the display panel and the optical laminate having the first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer of the first form can be attached by laminating under heat and/or pressure. . When attaching the display panel and the optical laminate having the first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer of the second form, the optical laminate is laminated under heat and/or pressure and then photocured. be able to. Photocuring can be performed in the same manner as the photocuring for forming the first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer of the first form.

When the first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer is formed from a solvent-based pressure-sensitive adhesive composition containing (meth)acrylic block copolymer A, the bonding is performed by heating and pressing at 50° C. or higher. is preferred. By heating and pressurizing at 50° C. or higher, the pressure-sensitive adhesive layer becomes highly fluid, and can sufficiently follow the steps of the LED chips arranged on the substrate and can be adhered without gaps. Heating is performed at 50° C. or higher, preferably 60° C. or higher, more preferably 70° C. or higher. Pressurization is not particularly limited, but is performed at, for example, 1.5 atm or more, preferably 2 atm or more, and more preferably 3 atm or more. Heating and pressurization can be performed using, for example, an autoclave. In the mini/micro LED display device thus produced, the storage elastic modulus of the pressure-sensitive adhesive layer is increased after returning to room temperature (25° C.), and workability and adhesion reliability are improved.

EXAMPLES The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples. Various properties in the production examples below were evaluated or measured by the following methods.

(Surface shape measurement)
A glass plate (thickness 1.3 mm) manufactured by Matsunami Glass Industry Co., Ltd. was pasted with an adhesive on the side of the anti-glare film on which the anti-glare layer was not formed, and a high-precision micro-shape measuring instrument (trade name: Surfcorder ET4000) was attached. , manufactured by Kosaka Laboratory Co., Ltd.), the surface shape of the anti-glare layer was measured under the condition of a cutoff value of 0.8 mm, and the average inclination angle θa was obtained. The high-precision fine shape measuring instrument automatically calculates the average inclination angle θa. The average inclination angle θa is based on JIS B 0601 (1994 version).

(Haze)
According to the method defined in JIS 7136, a haze meter (manufactured by Murakami Color Research Laboratory, trade name "HN-150") was installed so that light was incident from the antiglare layer surface of the antiglare film, and the haze value was measured.

(Visible light transmittance of adhesive sheet)
The release film on one side was peeled off from the pressure-sensitive adhesive sheet, and non-alkali glass was attached to the exposed side. After that, the release film on the other side was peeled off from the adhesive sheet to obtain a sample in which the adhesive sheet was attached to the non-alkali glass plate. Using this sample, the transmission spectrum of the evaluation sample was measured with a visible-ultraviolet spectrophotometer (manufactured by Hitachi High-Technologies, trade name "U-4100"). The ratio of the transmittance (amount of transmitted light) of the evaluation sample to the transmittance (amount of transmitted light) of the alkali-free glass was defined as the transmittance of the adhesive sheet, using the alkali-free glass (single body) as a baseline. The transmittance T _VIS at a wavelength of 550 nm was calculated from the transmittance spectrum of the adhesive sheet.

(Visible light transmittance of antiglare film)
The anti-glare film was placed in a spectrophotometer U4100 (manufactured by Hitachi High-Technology Co., Ltd.) so that light was incident from the anti-glare layer side, and the transmittance (%) in the visible light region was measured. This transmittance is a Y value measured with a 2-degree field of view (C light source) according to JIS Z8701 and subjected to visibility correction.

Production example 1
(Preparation of anti-glare film)
As a resin contained in the anti-glare layer, 100 parts by weight of an ultraviolet curable urethane acrylate resin (manufactured by DIC Corporation, trade name “Unidic 17-806”, solid content 80%) was prepared. Styrene crosslinked particles (manufactured by Soken Chemical Co., Ltd., trade name "MX-350H", weight average particle diameter: 3.5 μm, refractive index 1.59) are used as light diffusing fine particles per 100 parts by weight of the resin solid content of the resin. 14 parts by weight of synthetic smectite (manufactured by Kunimine Industries Co., Ltd., trade name "Smecton SAN"), which is an organic clay as a thixotropy-imparting agent, 2.5 parts by weight, and a photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907"). ”) was mixed with 0.5 parts by weight of a leveling agent (manufactured by DIC Corporation, trade name “Megafac F-556”, solid content 100%). This mixture was diluted with a toluene/ethyl acetate mixed solvent (weight ratio 90/10) so that the solid content concentration was 30% by weight to prepare a light diffusion element forming material (coating liquid).
An anti-glare layer-forming material (coating solution) was applied to one side of a triacetyl cellulose (TAC) film (manufactured by Fuji Film Co., Ltd., product name "TG60UL", thickness: 60 μm) that can function as a protective layer, using a bar coater, A coating was formed. Then, the transparent TAC film substrate on which this coating film was formed was transported to a drying step. In the drying step, the coating film was dried by heating at 110° C. for 1 minute. After that, ultraviolet rays with an accumulated light amount of 300 mJ/cm ² are irradiated with a high-pressure mercury lamp, and the coating film is cured to form a light diffusing element having a thickness of 5.0 μm on one side of the TAC film to obtain an anti-glare film 1. Ta. The haze value of antiglare film 1 was 42%. θa (°) of the antiglare layer of antiglare film 1 was 1.22. Visible light transmittance of antiglare film 1 was 90%.

Production example 2
(Preparation of anti-glare film)
14 parts by weight of amorphous silica (manufactured by Fuji Silysia Chemical Co., Ltd., trade name “Syrophobic 100”, weight average particle size: 2.6 μm) was added as light diffusing fine particles, and the thickness after curing was adjusted to 7.0 μm. An antiglare film 2 was obtained by forming a light diffusing element on one side of a TAC film in the same manner as in Production Example 1, except that the thickness was 0 μm. The haze value of antiglare film 2 was 11%. θa (°) of the antiglare layer of the antiglare film 2 was 1.43. Visible light transmittance of antiglare film 2 was 91%.

Production example 3
(Preparation of anti-glare film)
As a resin contained in the anti-glare layer forming material, 100 parts by weight of an ultraviolet curable urethane acrylate resin (manufactured by DIC Corporation, trade name “Unidic 17-806”, solid content 80%) was prepared. Per 100 parts by weight of the resin solid content of the resin, 7 parts by weight of amorphous silica (manufactured by Fuji Silysia Co., Ltd., trade name "Syrohobic 702") as anti-glare layer forming particles, ), trade name “Sylophobic 100”) 6.5 parts by weight, photopolymerization initiator (manufactured by BASF, trade name “OMNIRAD 184”) 5 parts by weight, leveling agent (manufactured by DIC Corporation, trade name 0.5 part by weight of "Megafac F-556"). This mixture was diluted with toluene so that the solid content concentration was 30% to prepare an anti-glare layer-forming material (coating liquid).
A transparent plastic film substrate (TAC film, manufactured by Fuji Film Co., Ltd., trade name “TD80UL”, thickness: 80 μm) was prepared as a translucent substrate. A coating film was formed on one side of the transparent plastic film substrate with the anti-glare layer-forming material (coating liquid) using a bar coater. Then, the transparent plastic film substrate on which this coating film was formed was transported to a drying step. In the drying step, the coating film was dried by heating at 110° C. for 1 minute. After that, the coating film was cured by irradiating ultraviolet light with an accumulated light quantity of 300 mJ/cm ² with a high-pressure mercury lamp to form an anti-glare layer having a thickness of 5.0 μm, and an anti-glare film 3 was obtained. θa (°) of the antiglare layer of antiglare film 3 was 3.5. The visible light transmittance of the antiglare film 3 was 91%.

Production example 4
(Preparation of anti-glare film)
As the anti-glare layer forming particles, 6.5 parts by weight of amorphous silica (manufactured by Fuji Silysia Co., Ltd., trade name "Silophobic 702"), amorphous silica (manufactured by Fuji Silysia Co., Ltd., trade name "Sylophobic 200”) was added, 2.5 parts by weight of a thickening agent (manufactured by Co-op Chemical, trade name “Lucentite SAN”) was added, and the thickness after curing was set to 8.0 μm. obtained an antiglare film 4 in the same manner as in Production Example 3. θa (°) of the antiglare layer of the antiglare film 4 was 2.3. The visible light transmittance of the antiglare film 4 was 91%.

Production example 5
(Preparation of prepolymer)
In a separable flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen gas introduction tube, 67 parts by weight of butyl acrylate (BA) and 14 parts of cyclohexyl acrylate (CHA, manufactured by Osaka Organic Chemical Industry, trade name "Viscoat #155") were added. parts by weight, 4-hydroxybutyl acrylate (4-HBA) 19 parts by weight, photopolymerization initiator (manufactured by BASF, trade name "Irgacure 184") 0.09 parts by weight, and photopolymerization initiator (manufactured by BASF, product After adding 0.09 part by weight of "Irgacure 651"), a nitrogen gas was supplied to replace the contents with nitrogen for about 1 hour while stirring. Thereafter, UVA was irradiated at 5 mW/cm ² to carry out polymerization, and the reaction rate was adjusted to 5 to 15% to obtain an acrylic prepolymer solution.

Production example 6
(Preparation of polymer RAFT solution A1)
A reaction vessel equipped with a cooling tube, a nitrogen inlet tube, a thermometer and a stirrer was charged with 50 parts by weight of cyclohexyl acrylate (CHA) as a monomer component, 50 parts by weight of 3,3,5-trimethylcyclohexyl acrylate (TMCHA) as a RAFT agent. 0.5 parts by weight of dibenzyltrithiocarbonate (DBTC), 100 parts by weight of ethyl acetate as a polymerization solvent, and 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as a thermal polymerization initiator. A polymer RAFT solution A1 having an Mw of 180,000 was obtained by introducing and performing solution polymerization in a nitrogen atmosphere.
(Preparation of Acrylic Triblock Copolymer-Containing Adhesive Solution B1)
97 parts by weight of 2-ethylhexyl acrylate (2EHA) and 3 parts by weight of 4-hydroxybutyl acrylate (4HBA) as monomer components were added to a reaction vessel equipped with a cooling tube, a nitrogen inlet tube, a thermometer and a stirrer. 100 parts by weight of polymer RAFT solution A1 and 100 parts by weight of ethyl acetate as a polymerization solvent were charged, and 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) was added as a thermal polymerization initiator, followed by nitrogen atmosphere. By carrying out solution polymerization under the following conditions, adhesive solution B1 containing an ABA-type acrylic triblock copolymer having Mw of 400,000 and Mw/Mn of 4.3 was obtained.
The Tg of segment A of the ABA-type acrylic triblock copolymer is 32°C, and the Tg of segment B is -70°C in the glass transition temperature (Tg) calculated by the FOX formula.
The weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn) of the above products were measured in terms of standard polystyrene by gel permeation chromatography (GCP method) under the following measurement conditions.
・ Measuring device: HLC-8320GPC (manufactured by Tosoh Corporation)
・ Column: TSKgelGMH-H (S), (manufactured by Tosoh Corporation)
・Mobile phase solvent: tetrahydrofuran ・Flow rate: 1.0 cm ³ /min
・Column temperature: 40°C

Production example 7
(Preparation of black adhesive composition)
9 parts by weight of 2-hydroxyethyl acrylate (HEA) and 8 parts by weight of 4-hydroxybutyl acrylate (4-HBA) were added to the acrylic prepolymer solution obtained in Production Example 7 (the total amount of the prepolymer being 100 parts by weight). , 0.02 parts by weight of dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Industrial Chemicals, trade name "KAYARAD DPHA") as a polyfunctional monomer, 0.35 parts by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and 0.3 parts of a photopolymerization initiator (manufactured by BASF, trade name "Irgacure 651") were added to prepare a photopolymerizable pressure-sensitive adhesive composition solution.
To 100 parts by weight of the photopolymerizable pressure-sensitive adhesive composition solution obtained above, 0.2 parts of a photopolymerization initiator (manufactured by BASF, trade name "Irgacure 651") and a black pigment dispersion (manufactured by Tokushiki Co., Ltd., 4 parts by weight of "TOKUSHIKI 9050 Black" (trade name) was added to prepare a photopolymerizable black adhesive composition solution.

Production example 8
(Preparation of black adhesive composition)
To the adhesive solution B1 containing the acrylic triblock copolymer obtained in Production Example 6, 2 parts by weight of a black dye ("VALIFAST BLACK 3810" manufactured by Orient Chemical Industry Co., Ltd.) is added to 100 parts by weight of the total monomer used in Production Example 6. ”) was added to prepare a black solvent-based pressure-sensitive adhesive composition solution.

Production example 9
(Preparation of adhesive composition)
9 parts by weight of 2-hydroxyethyl acrylate (HEA) and 8 parts by weight of 4-hydroxybutyl acrylate (4-HBA) were added to the acrylic prepolymer solution obtained in Production Example 5 (the total amount of the prepolymer being 100 parts by weight). , 0.12 parts by weight of dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Industrial Chemicals, trade name "KAYARAD DPHA") as a polyfunctional monomer, and 0.35 parts by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent was added to prepare a photopolymerizable adhesive composition solution.

Production example 10
(Preparation of adhesive sheet)
The black pressure-sensitive adhesive composition solution prepared in Production Example 7 was cured on the release surface of a 38 μm thick release film R1 (manufactured by Mitsubishi Plastics Co., Ltd., trade name “MRF#38”) in which one side of the polyester film was a release surface. The coating was applied to a thickness of 50 μm afterward, and was covered with a release film R2 (MRE #38, manufactured by Mitsubishi Plastics Co., Ltd.) having a release surface on one side of the polyester film to block air. Ultraviolet rays were irradiated from one side of this laminate using a black light (manufactured by Toshiba Corporation, trade name "FL15BL") under the conditions of an illuminance of 5 mW/cm ² and an integrated light amount of 1300 mJ/cm ² . As a result, PSA sheet 1 having a thickness of 50 μm in which the photocrosslinkable PSA, which is the cured product of the black PSA composition, was sandwiched between the release films R1 and R2 was obtained in the form of a substrate-less PSA sheet.
The values of the illuminance of the black light are the values measured by an industrial UV checker with a peak sensitivity wavelength of about 350 nm (manufactured by Topcon Corporation, trade name: UVR-T1, light receiving part type UD-T36).
Visible light transmittance of adhesive sheet 1 was 40%.

Production Example 11
(Preparation of adhesive sheet)
A photocrosslinkable pressure-sensitive adhesive, which is a cured product of the black pressure-sensitive adhesive composition, was sandwiched between release films R1 and R2 in the same manner as in Production Example 10, except that it was applied so that the thickness after curing was 100 μm. A pressure-sensitive adhesive sheet 2 having a thickness of 100 μm was obtained in the form of a substrate-less pressure-sensitive adhesive sheet.
The visible light transmittance of the adhesive sheet 2 was 16%.

Production example 12
(Preparation of adhesive sheet)
A photocrosslinkable adhesive, which is a cured product of the black adhesive composition, was sandwiched between release films R1 and R2 in the same manner as in Production Example 10, except that it was applied so that the thickness after curing was 150 μm. A pressure-sensitive adhesive sheet 3 having a thickness of 150 μm was obtained in the form of a substrate-less pressure-sensitive adhesive sheet.
The visible light transmittance of the adhesive sheet 3 was 3%.

Production example 13
(Preparation of adhesive sheet)
A 75 μm thick polyethylene terephthalate (PET) film (manufactured by Mitsubishi Chemical “Diafoil MRF75”) having a silicone-based release layer on the surface is used as a base material, and the black solvent-based adhesive prepared in Production Example 8 is applied on the base material. The composition solution was applied and dried at 130° C. for 3 minutes to form a pressure-sensitive adhesive layer with a thickness of 50 μm. On this adhesive layer, a 75 μm thick PET film ("Diafoil MRE75" manufactured by Mitsubishi Chemical) with one side subjected to silicone release treatment is laminated, and the adhesive sheet 4 with release films attached on both sides is attached to the baseless adhesive. Obtained in sheet form.
The visible light transmittance of the adhesive sheet 4 was less than 1%.

Production example 14
(Preparation of adhesive sheet)
A pressure-sensitive adhesive of a black solvent-based pressure-sensitive adhesive composition was prepared in the same manner as in Production Example 13, except that the black solvent-based pressure-sensitive adhesive composition solution prepared in Production Example 8 was applied so that the thickness after drying was 75 μm. A pressure-sensitive adhesive sheet 5 having a thickness of 75 μm in which a layer was sandwiched between release films was obtained in the form of a substrate-less pressure-sensitive adhesive sheet.
The visible light transmittance of the adhesive sheet 5 was less than 1%.

Production example 15
(Preparation of adhesive sheet)
A pressure-sensitive adhesive of a black solvent-based pressure-sensitive adhesive composition was prepared in the same manner as in Production Example 13, except that the black solvent-based pressure-sensitive adhesive composition solution prepared in Production Example 8 was applied so that the thickness after drying was 100 μm. A pressure-sensitive adhesive sheet 6 having a thickness of 100 μm in which a layer was sandwiched between release films was obtained in the form of a substrate-less pressure-sensitive adhesive sheet.
Visible light transmittance of the adhesive sheet 6 was less than 1%.

Production example 16
(Preparation of adhesive sheet)
A photocrosslinkable adhesive that is a cured product of the adhesive composition was prepared in the same manner as in Production Example 10, except that the adhesive composition solution prepared in Production Example 9 was applied so that the thickness after curing was 100 μm. A pressure-sensitive adhesive sheet 7 having a thickness of 100 μm in which the agent was sandwiched between the release films R1 and R2 was obtained in the form of a substrate-less pressure-sensitive adhesive sheet.
The visible light transmittance of the adhesive sheet 7 was 90%.

Production Example 17
(Preparation of adhesive sheet)
A photocrosslinkable adhesive that is a cured product of the adhesive composition in the same manner as in Production Example 10, except that the adhesive composition solution prepared in Production Example 9 was applied so that the thickness after curing was 200 μm A pressure-sensitive adhesive sheet 8 having a thickness of 200 μm in which the agent was sandwiched between the release films R1 and R2 was obtained in the form of a substrate-less pressure-sensitive adhesive sheet.
The visible light transmittance of the adhesive sheet 8 was 90%.

Example 1
(Preparation of optical laminate)
The adhesive surface exposed by peeling off one release film from the adhesive sheet 8 obtained in Production Example 17 cut to 20 mm × 20 mm was placed in the center of a 45 mm × 50 mm glass plate (visible light transmittance: 93%). After sticking, the other release film was peeled off to expose the adhesive surface. The adhesive surface exposed by peeling one release film from the adhesive sheet 1 obtained in Production Example 10 cut to 20 mm × 20 mm is attached to the adhesive surface of the adhesive sheet 8, thereby forming a glass plate/adhesive sheet. An optical laminate 1 consisting of 8/adhesive sheet 1/release film was obtained.

Examples 2-6
(Preparation of optical laminate)
Optical laminates 2 to 2 each comprising a glass plate/adhesive sheet 8/adhesive sheets 2 to 6/release film in the same manner as in Example 1, except that adhesive sheets 2 to 6 were used instead of adhesive sheet 1. got 6.

Comparative example 1
(Preparation of optical laminate)
An optical laminate 7 consisting of glass plate/adhesive sheet 8/adhesive sheet 7/release film was obtained in the same manner as in Example 1, except that adhesive sheet 7 was used instead of adhesive sheet 1.

(evaluation)
The following evaluations were performed using the optical layered bodies obtained in the above examples and comparative examples. The evaluation method is shown below.

(1) Evaluation of step followability (production of uneven adherend)
After pasting a laminate of TAC film (thickness 60 μm) and _adhesive (thickness 20 μm) to a glass plate of 45 mm × 50 mm, a central 10 mm × An adherend A in which the TAC film and the pressure-sensitive adhesive layer were processed into a grid-like uneven shape was obtained by performing linear etching processing within a range of 10 mm at a pitch of 150 μm in the vertical direction and a pitch of 225 μm in the horizontal direction.
This adherend A imitates an LED panel in which a plurality of LED films are arranged on a substrate.
(vacuum bonding)
The adhesive surface exposed by peeling off the release films of the optical laminates 1 to 7 prepared in Examples 1 to 6 and Comparative Example 1 and the processed surface of the adherend A were bonded together by a vacuum bonding apparatus (manufactured by CRIMB Products, Inc.). SE340aaH) is used to laminate the adherend A with a precision that the adhesive sheet can completely cover the processing range, and an evaluation sample consisting of a glass plate / adhesive sheet 8 / adhesive sheets 1 to 7 / adherend A 1-7 were obtained.
(Evaluation of step followability)
In the evaluation samples 1 to 7, when the adhesive sheet can follow the uneven pattern part, the processed part of the adherend A is visible transparently, and the part that cannot be followed is visible white. Then, the area of the white portion was calculated by photographing with a fixed-point camera to evaluate the step followability.

Step followability (%) = 100 - {[Area of white part at evaluation]/[Area of white part before lamination = 1 cm ² ] x 100}

The step followability was measured immediately after bonding and after autoclaving (50° C., 0.5 MPa for 15 minutes, 30 minutes, and 60 minutes). Table 1 shows the results.

(2) Visible light transmittance The optical laminates obtained in the above examples and comparative examples were placed in a spectrophotometer U4100 (manufactured by Hitachi High-Technology Co., Ltd.) so that light was incident from the glass plate side. The transmittance (%) of the light area was measured. This transmittance is a Y value measured with a 2-degree field of view (C light source) according to JIS Z8701 and subjected to visibility correction. Table 2 shows the results.

(3) Reflectance A plate was prepared by laminating an aluminum foil on a black acrylic plate. The adhesive surface exposed by peeling off the release film of the optical laminate obtained in the above Examples and Comparative Examples was laminated on the aluminum foil side of the above plate to obtain a sample. The resulting sample was placed in a spectrophotometer U4100 (manufactured by Hitachi High-Technology Co., Ltd.) with the antiglare film/TAC film placed on the light source side, and the reflectance (%) of the visible light range of 5° specular reflection was measured.

Example 7
(Preparation of optical laminate)
The anti-glare film 1 obtained in Production Example 1, which was cut to 45 mm × 50 mm, was exposed by peeling one release film from the adhesive sheet 8 obtained in Production Example 17 cut to 20 mm × 20 mm. After attaching the central part of the side where the anti-glare layer is not formed, the other release film is peeled off to expose the adhesive side. An anti-glare film 1/ An optical laminate 8 consisting of adhesive sheet 8/adhesive sheet 1/release film is obtained.

Examples 8-10
(Preparation of optical laminate)
Antiglare films 2 to 4/adhesive sheet 8/ Optical laminates 9 to 11 consisting of adhesive sheet 1/release film are obtained.

10, 11, 12 Optical laminate 1 First adhesive layer 2 Second adhesive layer 3 Base material 4 Antireflection treatment and/or antiglare treatment 4a Antiglare layer 20, 21, 22 Self-luminous display device (mini/micro LED display device)
5 substrate 6 metal wiring layer 7 light emitting element (LED chip)

Claims (17)

The first pressure-sensitive adhesive layer, the second pressure-sensitive adhesive layer, and the base material have a laminated structure laminated in this order,
The visible light transmittance T ₁ of the first pressure-sensitive adhesive layer and the visible light transmittance T ₂ of the second pressure-sensitive adhesive layer satisfy T ₁ <T ₂ ,
The surface of the substrate on which the second pressure-sensitive adhesive layer is not laminated is antireflection-treated and/or anti-glare-treated,
The ratio of the thickness of the second pressure-sensitive adhesive layer to the thickness of the first pressure-sensitive adhesive layer (thickness of the second pressure-sensitive adhesive layer/thickness of the first pressure-sensitive adhesive layer) is 1.0 to 5.0,
An optical laminate having a visible light transmittance of 40% or less. 2. The optical laminate according to claim 1, wherein the visible light transmittance _T1 of the first pressure-sensitive adhesive layer and the visible light transmittance _T3 of the base material satisfy _T1 < _T3 . The optical laminate according to claim 1 or 2, wherein the first pressure-sensitive adhesive layer has a visible light transmittance _T1 of 80% or less. The optical laminate according to any one of claims 1 to 3, wherein the second adhesive layer has a visible light transmittance T ₂ of 85 to 100%. The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are pressure-sensitive adhesive layers formed from a pressure-sensitive adhesive composition selected from photocurable pressure-sensitive adhesive compositions and solvent-based pressure-sensitive adhesive compositions, claims 1- 5. The optical laminate according to any one of 4. 6. The optical laminate according to claim 5, wherein the pressure-sensitive adhesive composition forming the first pressure-sensitive adhesive layer contains a colorant. 7. The optical laminate according to claim 5, wherein the adhesive composition contains an acrylic polymer. The optical laminate according to claim 7, wherein the acrylic polymer contains a (meth)acrylic block copolymer. 9. The optical laminate according to claim 8, wherein the pressure-sensitive adhesive composition forming the first pressure-sensitive adhesive layer is a solvent-based pressure-sensitive adhesive composition containing a (meth)acrylic block copolymer. The optical laminate according to any one of Claims 1 to 9, wherein the thickness of the first adhesive layer is 10 to 300 µm. The optical laminate according to any one of claims 1 to 10, wherein the thickness of the second adhesive layer is 1 to 500 µm. The optical laminate according to any one of claims 1 to 11 , wherein the antiglare treatment is an antiglare layer provided on one side of the substrate. The anti-glare layer is formed using an anti-glare layer-forming material containing a resin, particles and a thixotropy-imparting agent,
13. The optical layered body according to claim 12 , wherein the anti-glare layer has aggregated portions that form convex portions on the surface of the anti-glare layer by aggregation of the particles and the thixotropy-imparting agent. 14. The optical layered body according to claim 13 , wherein the convex portions on the surface of the antiglare layer have an average inclination angle θa (°) in the range of 0.1 to 1.5. 15. The optical layered body according to any one of claims 1 to 14 , further comprising a surface protective film laminated on the surface of the substrate on which the second pressure-sensitive adhesive layer is not laminated. a display panel in which a plurality of light emitting elements are arranged on one side of a substrate;
A self-luminous display device comprising the optical laminate according to any one of claims 1 to 15 ,
A self-luminous display device in which the surface of the display panel on which the light emitting elements are arranged and the first pressure-sensitive adhesive layer of the optical layered body are laminated. 17. The self-luminous display device according to claim 16 , wherein said display panel is an LED panel in which a plurality of LED chips are arranged on one side of a substrate.

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