JP2013254117A - Optical laminate, and polarizing plate using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical laminate which suppresses the occurrence of interference fringes, suppresses the occurrence of a crack in a frame printing pattern, and has good adhesion with a base material, and a polarizing plate using the same.SOLUTION: Provided is an optical laminate that includes, on one face of a light-transmitting base material, a frame printing pattern, a protective printing pattern and a hard coat layer in a predetermined positional relationship, wherein the frame printing pattern is a cured product of a curable resin composition including a colorant and a curable resin, the hard coat layer is a cured product of an ionizing radiation-curable resin composition, and the protective printing pattern is a cured product of a curable resin composition at least including acrylic polyol. There is also provided a polarizing plate that includes a polarizer protective sheet, a polarizer, and the optical laminate in order.

Description

  The present invention relates to an optical laminate and a polarizing plate using the same.

  The thickness and thickness of liquid crystal displays (LCD), plasma displays (PDP), inorganic and organic LED (light-emitting diode) displays, displays and touch panels used for electronic paper, etc. are greatly affected by their appearance and performance. Is required to be thin. With the demand for such a thin display, the polarizing plate provided in the display or the like is also required to be thin.

As a polarizing plate provided on the viewer side of these displays, for example, as a polarizing plate for a liquid crystal display (LCD), a polarizing plate is laminated between an image source side protective sheet and an observation side protective sheet. As a polarizing plate for an organic EL display (OLED), a polarizing plate is used between a retardation film on the image source side and a protective sheet on the observer side. In addition, a polarizing plate is used for the purpose of concealing the driver IC and wiring provided near the outer peripheral frame of the display, improving the design of the display, or preventing leakage of light such as backlight from outside the image display area. A frame print pattern is provided on any of the layers that constitute the image (for example, Patent Document 1).
The present inventors also used an optical laminate having a frame print pattern on one surface of the light-transmitting substrate and a hard coat layer on the other surface as a polarizing plate, and the surface of the frame print pattern side and the polarizing plate. The polarizing plate of the 1st aspect which has an observer side protective sheet surface through the adhesive layer of thickness of dozens of micrometers has been developed. However, since this polarizing plate has a large number of layers and becomes thick, there is a problem that it cannot fully meet the demand for thin display. In addition, there is a problem that the number of manufacturing steps increases and the amount of materials used is high, and thus the cost becomes high.

JP 2011-221371 A

In view of the problems as described above, the inventors of the present invention have the light transmissive substrate of the optical laminate having the hard coat layer in the polarizing plate of the first aspect, which also serves as a protective sheet on the observer side. By doing so, the number of layers is reduced, and a second mode in which a frame print pattern is provided between the polarizer and the light-transmitting substrate is being developed.
The frame printing pattern is a layer for concealing the driver IC and wiring provided in the vicinity of the outer peripheral frame of the normal display as described above, and is provided along the outer peripheral frame of the optical laminate. Therefore, the polarizing plate of the second aspect is provided with a smooth layer made of a transparent resin that fills the space inside the frame print pattern together with the frame print pattern on one surface of the light transmissive substrate, and is bonded to the polarizer. can get. However, in this configuration, the adhesive layer that bonds the observer-side protective sheet and the polarizer needs to be very thin, tens to hundreds of nanometers, so as not to deteriorate the polarization performance of the polarizer. Therefore, if even a slight step is formed, the performance as a polarizing plate may be deteriorated due to the generation of bubbles due to the step. On the other hand, it is extremely difficult to provide a frame printing layer and a smooth layer without a step on a light-transmitting substrate with a general-purpose manufacturing device, and this will place an excessive load on the manufacturing device or manufacturing conditions. As a result, the ease of production and the yield decrease.

Therefore, the present inventors reduce the number of layers by making the optically transmissive substrate of the optical laminate having a hard coat layer in the optical laminate also serve as a protective sheet on the observer side, Furthermore, in consideration of the ease of production, etc., the third mode in which a frame printing pattern is provided between the observer-side surface of the light-transmitting substrate and the hard coat layer is also being developed.
In this embodiment, since the surface of the light-transmitting substrate having high smoothness is used as the bonding surface with the polarizer, the light-transmitting substrate and the polarized light can be bonded even with an adhesive layer having a thickness of several tens to several hundreds of nanometers. The child can be easily stacked. On the other hand, in an optical film, since a solvent is generally contained in the ionizing radiation curable resin composition forming the hard coat layer, the curable resin forming the frame printing pattern is attacked by the solvent. In some cases, the frame printing pattern cracks or the adhesiveness with the base material is lowered. Therefore, it has been a problem to suppress the occurrence of cracks in the frame print pattern and to obtain excellent adhesion to the substrate.

  As a result of intensive studies to solve the above problems, the present inventors can solve the above problems by specifying a material that forms a protective print pattern for protecting the frame print pattern. I found. The gist of the present invention is as follows.

1. On one surface of the light transmissive substrate, a frame print pattern, a protective print pattern, and a hard coat layer are provided, and the frame print pattern is provided along the outer periphery of the light transmissive substrate. A print pattern is provided so as to cover the frame print pattern and between the frame print pattern and the hard coat layer, and the hard coat layer covers the light transmissive substrate and the protective print pattern. The frame printing pattern is a cured product of a curable resin composition containing a colorant and a curable resin, and the hard coat layer is a cured product of an ionizing radiation curable resin composition, The optical laminate is a cured product of a curable resin composition containing at least an acrylic polyol.
2. 2. The optical laminate according to 1 above, wherein the material constituting the light transmissive substrate is triacetylcellulose, and the impregnated layer is provided at a portion where the light transmissive substrate and the hard coat layer are in contact with each other.
3. The polarizing plate which has a polarizer protective sheet, a polarizer, and the optical laminated body of said 1 or 2 in order.
4). 3. An image display device comprising the optical laminate according to 1 or 2 or the polarizing plate according to 3 above.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of the crack of a frame printing pattern can be suppressed, and the optical laminated body which has the adhesiveness with the outstanding base material, and a polarizing plate using the same can be provided.

It is a schematic diagram which shows the cross section of the optical laminated body of this invention. It is a schematic diagram which shows the cross section of the optical laminated body of this invention. It is the schematic diagram seen from the upper surface of the optical laminated body of this invention. It is a schematic diagram which shows the cross section of the polarizing plate of this invention.

[Optical laminate]
The optical layered body of the present invention has a frame printing pattern, a protective printing pattern, and a hard coat layer on one surface of a light-transmitting substrate, and the material constituting the light-transmitting substrate is triacetyl cellulose. The frame printing pattern is provided along the outer periphery of the light-transmitting substrate, the protective printing pattern covers the frame printing pattern, and the frame printing pattern and the hard coat layer The hard coat layer is provided on the entire surface so as to cover the light-transmitting substrate and the protective printing pattern, and the frame printing pattern includes a colorant and a curable resin. The hard coat layer is a cured product of an ionizing radiation curable resin composition, and the protective printing pattern is a cured product of a curable resin composition containing at least an acrylic polyol. That.

FIG. 1 and FIG. 2 are schematic views showing a cross section of a preferred embodiment of the optical laminate of the present invention. On one surface of the light-transmitting substrate 1, a frame printing pattern 2, a protective printing pattern 3, and a hardware The mode which has the impregnation layer 5 in the part which the coating layer 4 and this light-transmitting base material 1 and the hard-coat layer 4 contact | connect is shown.
Hereinafter, the configuration of the optical layered body of the present invention will be described in detail with reference to FIGS.

(Light transmissive substrate)
It is preferable that the light-transmitting substrate is light-transmitting, has smoothness and heat resistance, and is excellent in optical performance and mechanical performance. The light transmissive substrate preferably has a light transmittance of 80% or more in the visible light region of 380 to 780 nm, and more preferably 90% or more. Here, the light transmittance is a value measured in accordance with JIS K7361-1 (Testing method for total light transmittance of plastic-transparent material).
Such a light-transmitting substrate is not particularly limited as long as it has the above-described light-transmitting properties. For example, a flexible material made of a resin material or a flexible material such as a glass substrate. The rigid material etc. which do not have these are mentioned preferably, and a flexible material is more preferable from a viewpoint of obtaining the outstanding productivity. The resin material constituting the flexible material may be appropriately selected according to the use of the optical laminate of the present invention. For example, cellulose resin such as triacetyl cellulose (TAC), diacetyl cellulose, acetate butyrate cellulose, cellophane, etc. A cyclopolyolefin resin obtained from a cycloolefin such as norbornene, dicyclopentadiene, tetracyclododecene; polyethylene terephthalate resin (PET), polybutylene terephthalate resin, polyethylene naphthalate-isophthalate copolymer resin, polyester thermoplastic elastomer, etc. Preferred examples of the polyester resin include: acrylic resins such as methyl (meth) acrylate resin and butyl (meth) acrylate resin; and polycarbonate resins.
Among these, a polyester resin is preferable in consideration of mechanical performance, particularly heat resistance, and a cyclopolyolefin resin and a cellulose-based resin are preferable in consideration of optical performance, particularly polarization, and triacetyl cellulose (TAC) is particularly preferable. preferable.

  What is necessary is just to select the thickness of a light-transmitting base material suitably in consideration of the use of the optical laminated body of this invention, the material which comprises a base material, etc., and is about 5-200 micrometers normally. Moreover, when selecting a cellulose resin as a material, Preferably it is 15-100 micrometers, More preferably, it is 20-80 micrometers. This is because when the thickness of the light-transmitting substrate is within the above range, the optical layered body of the present invention can be thinned and sufficient mechanical strength can be ensured.

  In addition, a surface treatment such as corona treatment, plasma treatment, low-pressure UV treatment, saponification treatment, or an anchor layer is formed on the light-transmitting substrate in order to improve adhesion with a frame printing pattern or a polarizer described later. An easy adhesion treatment such as a method can be performed, or an easy adhesion layer (primer layer) can be provided. Of these, a corona treatment, a method of forming an anchor layer, and a method of using these in combination are preferable.

(Frame print pattern)
The frame print pattern is a pattern that is provided along the outer periphery of the light-transmitting substrate and is made of a cured product of a curable resin composition containing a colorant and a curable resin. When the optical laminate of the present invention is used as a protective film for polarizing plates used in various displays, this frame printing pattern is usually provided near the outer peripheral frame of the display to improve design and conceal driver ICs and wiring. This is a layer provided for the purpose.
In the present invention, “provided along the outer periphery” means that the outer periphery of the effective screen of the display is provided in order to conceal the driver IC and wiring provided in the vicinity of the outer peripheral frame. It is a concept indicating that it is provided in the vicinity of the frame and provided so as not to impair the visibility of the display image on the display. In other words, it does not have to be strictly along the outer periphery, and does not necessarily have to be along the outer periphery as long as it is in the vicinity of the outer periphery and does not impair the visibility of the display image on the display. It is a concept including a mode in which a part thereof is missing. FIG. 3 is a schematic view of the optical layered body of the present invention as viewed from the upper surface, and the frame print pattern is provided on the entire outer periphery along the outer periphery, and this is an example of the aspect of providing the frame print pattern in the present invention. It is shown.

  The transmission density of the frame print pattern is preferably 3 to 8, more preferably 4 to 6, and further preferably 4.5 to 5.6. When the transmission density of the frame print pattern is 3 or more, the driver IC and wiring provided near the outer peripheral frame of the normal display can be sufficiently hidden. Moreover, since it is not necessary to make the thickness of a frame printing pattern too thick as it is 8 or less, it is suitable. The transmission density is an optical density measured by a transmission densitometer as a ratio of transmitted light to incident light for a film or the like standardized by ISO5-2 (2009) series.

The curable resin is not particularly limited as long as it is a room temperature curable resin, a thermosetting resin, a moisture curable resin, and an ionizing radiation curable resin. However, it maintains the mechanical strength of the light-transmitting substrate and is easy to manufacture. In view of productivity and productivity, it is preferable to use a thermosetting resin.
As the curable resin, various ones such as a one-part curable resin, a two-part curable resin, and an emulsion type can be used. Adhesion with a light-transmitting substrate, heat resistance, and ease of handling Taking these into consideration, a two-component curable resin is preferable. The types of curable resins include urethane resins, acrylic polyol resins, epoxy resins, phenol resins, amino resins, alkyd resins, nitrocellulose resins, unsaturated polyester resins, vinyl acetate resins, ethylene-vinyl acetate copolymers, Preferred examples include vinyl chloride-vinyl acetate copolymer, and urethane resin, acrylic polyol resin, nitrocellulose resin, vinyl chloride-vinyl acetate copolymer are considered in consideration of adhesion to a light-transmitting substrate and ease of handling. Is preferred. These resins may be modified.
In the present invention, the curable resin can be used alone or in combination of a plurality of these, and from the viewpoint of improving adhesion, a urethane resin alone, a combination of a urethane resin and a nitrocellulose resin, an acrylic polyol A combination of resin and vinyl chloride-vinyl acetate copolymer, and a combination of urethane resin and vinyl chloride-vinyl acetate copolymer are preferred. In consideration of a combination with a resin used for forming a protective printing pattern described later, a urethane resin alone or a combination of a urethane resin and a vinyl chloride-vinyl acetate copolymer is more preferable.

The weight average molecular weight in terms of standard polystyrene before curing of the curable resin is 10,000 to 100,000, preferably 30,000 to 70,000. It is preferable for the weight average molecular weight to be in the above-mentioned range since excellent adhesion to a light-transmitting substrate, heat resistance and ease of handling can be obtained.
In the case of a two-component curable resin, the curing agent is appropriately selected depending on the type of the resin component described above. For example, a polyisocyanate compound, an organic sulfonate, an organic amine, an aziridine compound having an aziridine ring, a melamine compound, a carbodiimide compound, Preferred examples include radical initiators. Of these, polyisocyanate compounds are preferred.

  As the colorant, a color dye, a color pigment, and the like can be used. It is preferable to use a color pigment because it conceals the driver IC and the wiring and hardly causes discoloration. Examples of coloring pigments include carbon black, titanium black, iron black, pearl pigment, dial, cadmium red, ultramarine, bitumen, cobalt blue, chromium oxide green, cobalt green, chrome lead, titanium yellow, titanium oxide, zinc white, Inorganic pigments such as lead white, lithopone, barite, precipitated barium sulfate, calcium carbonate, precipitated silica, and silver pigments such as aluminum paste are preferred, and among these, use alone or in combination. I get out. Among them, from the viewpoint of concealing the driver IC and wiring provided near the outer peripheral frame of the display and making it close to the color of the display when the display is turned off and making it inconspicuous, for example, a colored pigment exhibiting a dark color such as black or gray Preferred are silver pigments such as carbon black and aluminum paste, and pearl pigments.

  Examples of the carbon black include carbon black such as furnace black, channel black, thermal black, lamp black, and acetylene black. The average primary particle size of carbon black is preferably 5 to 70 nm, more preferably 5 to 60 nm, still more preferably 5 to 50 nm, and particularly preferably 20 to 30 nm. If the average primary particle size of the carbon black is within the above range, excellent concealing properties can be obtained. Here, the average primary particle size is determined by using a transmission electron microscope (TEM) after spreading and drying a dispersion obtained by sufficiently diluting and dispersing carbon black with a solvent such as chloroform on a mesh with a collodion film. Computer image analysis of the photographed TEM photograph, the diameter of a circle having an area equal to the area of each extracted aggregate (equal area circle diameter) as the particle diameter, and the arithmetic average diameter obtained from the obtained particle size distribution (Number average value).

  Carbon black preferably has a DBP oil absorption of 40 to 150 ml / 100 g, more preferably 40 to 130 ml / 100 g, and even more preferably 50 to 120 ml / 100 g. If the DBP oil absorption is within the above range, good printability can be obtained, so that good concealability can be obtained. Here, the DBP oil absorption is a value measured by the JIS K6221 A method.

The specific surface area of the carbon black is preferably 10 to 300 m ² / g, more preferably 10~250m ² g, further preferably 20~250m ² / g. If the specific surface area is within the above range, the black density can be improved, and good printability can be obtained, so that good concealability can be obtained. Here, the specific surface area is a value measured according to JIS K6221 by nitrogen adsorption.
The pH of the carbon black is not particularly limited, but is preferably 3 to 10, more preferably 3 to 7, and further preferably 3 to 5 from the viewpoint of improving the storage stability in the curable resin composition. The pH of carbon black is determined by preparing an aqueous suspension and measuring with a glass electrode.

  Carbon black may be subjected to oxidation treatment. The oxidation treatment of carbon black is performed by putting carbon black in an aqueous solution of an oxidizing agent such as sulfuric acid, nitric acid, chlorate, persulfate, and stirring and mixing. This oxidation treatment is preferably performed at room temperature to about 90 ° C. Oxidized carbon black is a surface modified by the formation of carboxyl groups, hydroxyl groups, etc. on its surface, and the storage stability of the curable resin composition is improved by using such carbon black. .

  As for content of the coloring agent in curable resin composition, 10-70 mass parts is preferable with respect to 100 mass parts of curable resin compositions, More preferably, it is 10-50 mass parts, More preferably, 20- 50 parts by mass. When the content of the colorant is within the above range, good concealability can be obtained, the curable resin composition can be easily applied, the productivity is excellent, and the storage stability is also good.

The thickness of the frame print pattern is preferably 2 to 5 μm, more preferably 3.5 to 4.5 μm. When the thickness of the frame print pattern is within the above range, good concealability can be obtained, and excellent smoothness of the surface of the hard coat layer can be obtained. Here, as for the thickness of the frame print pattern, for example, using a film thickness meter or from a cross-sectional photograph of the optical laminate of the present invention, the pattern on the print surface of the frame print pattern and the vicinity of the frame print pattern are printed. Three points are measured on each non-printed surface, and the difference between the average value of the printed surface of the frame print pattern and the average thickness of the non-printed surface is taken as the thickness of the frame print pattern. it can.
The width of the frame print pattern is appropriately determined depending on the driver IC to be concealed, the installation width of the wiring, the appearance of the display design, etc., but is usually preferably 3 to 20 mm, more preferably 5 to 15 mm. It is. If the width of the frame print pattern is within the above range, it is sufficient to conceal the driver IC and the wiring, and the appearance of the display is not deteriorated.

(Protective print pattern)
The protective print pattern is a layer provided so as to cover the frame print pattern and between the frame print pattern and the hard coat layer. When a penetrating solvent is used in an ionizing radiation curable resin composition for forming a hard coat layer, which will be described later, the frame print pattern is cracked by the attack by the penetrating solvent, or the adhesion to the substrate is reduced. May end up. In the present invention, a protective print pattern is provided to protect the frame print pattern from such a solvent attack. A frame printing pattern in which the content of the colorant is increased in order to improve the concealing property is particularly useful because of poor solvent resistance.

The protective printing pattern is constituted by a cured product of a curable resin composition containing at least an acrylic polyol resin. When an acrylic polyol resin is used in the protective printing pattern, adhesion between the protective printing pattern and the light-transmitting substrate, the frame printing pattern, and the hard coat layer is obtained. As a result, an optical laminate having excellent adhesion can be obtained. can get.
In the present invention, as the acrylic polyol resin, (meth) acrylic acid alkyl ester such as ethyl (meth) acrylate is copolymerized with hydroxy acrylate such as 2-hydroxyethyl acrylate and 2-hydroxy-3-phenoxypropyl acrylate. And those having a plurality of hydroxyl groups introduced are preferred. Then, the curable resin composition containing the acrylic polyol resin is cured using a curing agent such as an isocyanate compound that is preferably used for forming the frame printing pattern, thereby obtaining a protective printing pattern.

  The acrylic polyol resin used for the formation of the protective printing pattern has a weight average molecular weight of 10,000 to 100,000, preferably 40,000 to 80,000, as converted with standard polystyrene before curing. It is preferable for the weight average molecular weight to be within the above range since adhesion and ease of handling can be obtained.

  The glass transition temperature Tg of the acrylic polyol (when uncured) is preferably 50 ° C. or higher, more preferably 65 ° C. or higher, and the upper limit of the glass transition temperature Tg is not particularly limited, but is usually about 110 ° C. Among them, the preferable Tg range is 70 to 100 ° C. When the glass transition temperature Tg is within the above range, excellent adhesion can be obtained.

As the resin for forming the protective printing pattern, a resin in which an acrylic polyol resin and another resin are used in combination is also preferable. For example, further improvement in adhesion can be expected by using an acrylic polyol resin and a vinyl chloride-vinyl acetate copolymer in combination.
When the acrylic polyol resin and vinyl chloride-vinyl acetate copolymer are used in combination, the blending ratio (mass ratio) is preferably 9: 1 to 5: 5, more preferably 8: 2 to 6: 4. It is.

The shape of the protective print pattern is not particularly limited as long as it covers the frame print pattern and is provided between the frame print pattern and the hard coat layer. For example, as shown in FIG. It may have a shape that covers the print pattern, or may have a stepped shape as shown in FIG. 2 in order to further protect the frame print pattern.
The thickness of the protective printing pattern is preferably 0.5 to 2.5 μm, more preferably 1 to 2 μm. When the thickness of the protective printing pattern is within the above range, excellent protection performance of the frame printing pattern can be obtained, and excellent smoothness of the surface of the hard coat layer can be obtained. Here, the thickness of the protective print pattern is, for example, printed on the printed surface of the protective print pattern and in the vicinity of the protective print pattern using a film thickness meter or from a cross-sectional photograph of the optical laminate of the present invention. Three points are measured on each non-printed surface, and the thickness of the protective print pattern is determined by the difference between the average value of the printed surface thickness of the protective print pattern and the average thickness of the non-printed surface. it can.
Further, the width of contact between the protective printing pattern and the light transmissive substrate is equal to or greater than the thickness of the protective printing pattern, and when the thickness is equal to or larger than the thickness of the protective printing pattern, the shape of the protective printing pattern Is preferably a stepped shape as shown in FIG. In this case, the width of contact between the protective printing pattern and the light transmissive substrate is preferably 0.1 mm to 2 mm, more preferably 0.3 mm to 2 mm, and still more preferably 0.3 mm to 1.2 mm. It is. When the width of contact between the protective printing pattern and the light-transmitting substrate is within the above range, excellent protective performance is obtained, and the protective printing pattern is not visually recognized, and the design property is not deteriorated. If the area where the protective printing pattern and the light transmissive substrate are in contact is large, such as when the protective printing pattern is provided on the entire surface of the display, the difference in refractive index between the protective printing pattern and the light transmissive substrate will be described later. There is a case where the problem of generation of interference fringes due to the above occurs, and it is preferable to set the width as described above.

(Hard coat layer)
The hard coat layer is a layer made of a cured product of an ionizing radiation curable resin composition, provided for the purpose of improving surface hardness performance such as scratch resistance on the optical laminate of the present invention. Here, the hard coat refers to a performance showing a hardness of “H” or higher in a pencil hardness test specified in JIS 5600-5-4: 1999.

  The ionizing radiation curable resin composition forming the hard coat layer is preferably a resin composition containing a solvent, a photopolymerization initiator, and various additives in addition to the ionizing radiation curable resin. The ionizing radiation curable resin is one having an energy quantum capable of polymerizing molecules in electromagnetic waves or charged particle beams, that is, a resin that is cured by irradiation with ultraviolet rays or electron beams, etc. From the viewpoints of obtaining excellent surface hardness and easily imparting performance such as solvent resistance and antifouling property, an ultraviolet curable resin composition that is cured by irradiation with ultraviolet rays is preferable.

  Such a resin can be appropriately selected from polymerizable monomers and polymerizable oligomers (or prepolymers) conventionally used as ionizing radiation curable resins.

As the polymerizable monomer, a (meth) acrylate monomer having a radically polymerizable unsaturated group in the molecule is preferable, and a polyfunctional (meth) acrylate monomer is particularly preferable.
The polyfunctional (meth) acrylate monomer is not particularly limited as long as it is a (meth) acrylate monomer having two or more ethylenically unsaturated bonds in the molecule. Specifically, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, pentaerythritol di (meth) acrylate monostearate, dicyclopentanyl di (meth) acrylate, isocyanurate di (meth) acrylate, etc. Di (meth) acrylate; tri (meth) acrylate such as trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, tris (acryloxyethyl) isocyanurate; pentaerythritol tetra (meth) acrylate, dipentaerythritol Tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate and other (meth) acrylates ; Polyfunctional described above (meth) acrylate monomers of ethylene oxide-modified products, propylene oxide-modified products, caprolactone modified products, such as propionic acid-modified products are preferably exemplified. Among these, from the viewpoint of obtaining excellent surface hardness, polyfunctional (that is, trifunctional or higher) (meth) acrylate is preferable to tri (meth) acrylate. These polyfunctional (meth) acrylate monomers may be used individually by 1 type, and may be used in combination of 2 or more type.

  In the present invention, a monofunctional (meth) acrylate monomer is used in combination with the above-described polyfunctional (meth) acrylate monomer as long as the purpose of the present invention is not impaired, for the purpose of, for example, reducing the viscosity. Can do.

  As the polymerizable oligomer, an oligomer having a radical polymerizable unsaturated group in the molecule, for example, epoxy (meth) acrylate type, urethane (meth) acrylate type, polyester (meth) acrylate type, polyether (meth) acrylate type An oligomer etc. are mentioned preferably. Furthermore, examples of the polymerizable oligomer include a highly hydrophobic polybutadiene (meth) acrylate oligomer having a (meth) acrylate group in the side chain of the polybutadiene oligomer, and a silicone (meth) acrylate oligomer having a polysiloxane bond in the main chain. Preferably mentioned.

The polymerizable oligomer preferably has a number average molecular weight (polystyrene converted number average molecular weight measured by GPC method) of 20,000 or less, preferably 20,000 or less, more preferably 300 to 10,000. Yes, more preferably 300 to 5,000. By using such a polymerizable oligomer, heat generation and shrinkage due to polymerization can be suppressed, and damage (wrinkles) and curling due to heat generation can be prevented.
The polymerizable oligomer is preferably polyfunctional, more preferably 3 to 12 functional, and further preferably 3 to 10 functional. When the number of functional groups is within the above range, excellent surface characteristics can be obtained.

The ionizing radiation curable resin can be used in combination with a solvent-drying resin. This is because by using the solvent-drying resin in combination, it is possible to effectively prevent adhesion defects with the light-transmitting substrate and coating defects on the coated surface, so that excellent surface hardness performance can be obtained.
Examples of the solvent-drying resin include styrene resin, (meth) acrylic resin, polyolefin resin, vinyl acetate resin, vinyl ether resin, halogen-containing resin, polycarbonate resin, polyester resin, polyamide resin, nylon, cellulose resin, silicone resin, Preferable examples include simple substances and copolymers of thermoplastic resins such as polyurethane resins, or mixed resins thereof. These resins are preferably amorphous and soluble in a solvent. In particular, a styrene resin, a (meth) acrylic resin, a polyolefin resin, a polyester resin, a cellulose resin, and the like are preferable from the viewpoints of film forming properties, transparency, weather resistance, and the like.

When an ultraviolet curable resin is used as the ionizing radiation curable resin, it is preferable to add about 0.5 to 10 parts by mass of the photopolymerization initiator with respect to 100 parts by mass of the ionizing radiation curable resin. Addition of parts by mass is more preferred. The photopolymerization initiator can be appropriately selected from those conventionally used. For example, acetophenone, benzophenone, alkylphenone, benzoin, ketal, anthraquinone, disulfide, thioxanthone, thiuram And photopolymerization initiators such as fluoroamines, and any of these may be used alone or in combination of two or more.
Of these, radical photopolymerization initiators such as acetophenone, alkylphenone, benzoin, benzophenone, anthraquinone, and thioxanthone, which generate radicals upon irradiation with ionizing radiation and can trigger curing of the resin composition, are preferred. Furthermore, from the viewpoint of light transmittance, acetophenone-based and alkylphenone-based ones are preferable, and hydroxyacetophenone-based, hydroxyalkylphenone-based, and aminoalkylphenone-based ones are more preferable. Such photopolymerization initiators are available as commercial products. For example, “Irgacure 184 (trade name)” (1-hydroxy-cyclohexyl-phenyl ketone), “Irgacure 907 (trade name)” (2-methyl- 1- (4-methylthiophenyl) -2-morpholinopropan-1-one), “Irgacure 127 (trade name)” (2-hydroxy-1- [4- [4- (2-hydroxy-2-methylpropionyl) )] Benzyl] phenyl] -2-methylpropan-1-one) (both manufactured by BASF).

  The solvent contained in the ionizing radiation curable resin composition can be used without particular limitation as long as it is a solvent used in the resin composition for providing each layer of the optical laminate, but as a material for forming a light-transmitting substrate. Cellulose resin, especially triacetyl cellulose is used, and when the hard coat layer is a so-called non-glare hard coat layer (glare), the permeable solvent has permeability to the light-transmitting substrate. Is preferably used. In such a case, interference fringes may occur due to interference between the surface reflection of the hard coat layer and the interface reflection between the hard coat layer and the light transmissive substrate, which may be a factor in reducing the performance of the optical laminate. is there. In order to reduce the occurrence of the interference fringes, it is effective to reduce the difference in refractive index at the interface between the light-transmitting substrate and the hard coat layer. As the method, it is preferable to form an impregnation layer to be described later, which is a layer in which the monomer or an oligomer having a low molecular weight penetrates into the substrate. Therefore, when the permeable solvent is used as the solvent, the monomer and the oligomer having a small molecular weight penetrate more into the base material, so that the impregnated layer is easily formed. Here, the permeable solvent is a solvent having performance such as permeability, swelling property, wettability, and osmotic solubility with respect to the light-transmitting substrate.

Such penetrating solvents include acetone, methyl ethyl ketone, diethyl ketone, cyclohexanone, cycloheptanone, methyl isobutyl ketone, diacet alcohol, and other ketones; methyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, lactic acid Esters such as ethyl; nitrogen-containing compounds such as nitromethane, acetonitrile, N-methylpyrrolidone, N, N-dimethylformamide; ethers such as tetrahydrofuran, 1,4-dioxane, dioxolane, diisopropyl ether; methylene chloride, chloroform, tetra Halogenated hydrocarbons such as chloroethane; glycol ethers such as methyl glycol, methyl glycol acetate, methyl cellosolve, ethyl cellosolve, butyl cellosolve, cellosolve acetate S, and the like preferably can be used alone or in combination from among these, or a plurality of types.
In the present invention, ketones or esters are preferable from the viewpoint of reducing interference fringes by penetrating into the light-transmitting substrate, and methyl ethyl ketone and cyclohexanone are particularly preferable.

Moreover, it is preferable to use a non-permeable solvent as a solvent in combination with the above-mentioned permeable solvent. If the penetrating solvent alone is too permeable, swellable, wettable, penetrable, etc. for the light-transmitting substrate, combining the non-permeable solvent makes the light-transmitting substrate and hard coat layer To suppress the whitening that occurs when the thickness of the impregnated layer formed on the contacting part is increased, and to easily adjust to the desired thickness, and to improve the dispersion and solubility of various additives that will be described later This is because it becomes possible.
Examples of such non-permeable solvents include ketones such as methyl isobutyl ketone and diethyl ketone; esters such as isopropyl acetate, butyl acetate and ethyl lactate; glycol ethers such as methyl glycol and ethyl glycol acetate; isopropyl alcohol and butanol. Alcohols such as are preferable, and among these, they can be used alone or in combination. Of these, butanol is preferred. Here, there is an overlapping solvent between the above-mentioned permeable solvent and non-permeable solvent, but it can be either permeable or non-permeable due to the relative strength of osmosis combined with each other. These are listed in a duplicated manner because they are preferably used as an organic solvent.
The amount of the non-permeable solvent used is 5 to 80 parts by mass with respect to 100 parts by mass of the osmotic solvent from the viewpoint of suppressing generation of interference fringes and suppressing generation of whitening due to formation of the osmotic layer. Preferably, it is 10-40 mass parts.

  The content of the solvent in the ionizing radiation curable resin composition is usually 20 to 70% by mass, preferably 30 to 65% by mass, and more preferably 35 to 60% by mass. When the content of the solvent is within the above range, the impregnated layer can be stably formed, the coating suitability is excellent, and the dispersion stability and long-term storage stability of the resin component are excellent. The solvent used in the ionizing radiation curable resin composition does not exist in the hard coat layer because it evaporates by the drying and curing treatment performed after the composition is applied.

Various additives can be added to the ionizing radiation curable resin composition according to desired performance.
As various additives, inorganic or organic fine particles are preferably mentioned. Examples of such fine particles include SiO ₂ (refractive index n = 1.45), MgF ₂ (refractive index n = 1.38), LiF (refractive index n = 1.36) for the purpose of reducing the reflectance. NaF (refractive index n = 1.33), CaF ₂ (refractive index n = 1.44), 3NaF · AlF ₃ (refractive index n = 1.4), AlF ₃ (refractive index n = 1.37), Low-refractive-index fine particles such as Na ₃ AlF ₆ (refractive index n = 1.33) are ZnO (refractive index n = 1.9), TiO ₂ (refractive index n = 2. 3 to 2.7), CeO ₂ (refractive index n = 1.95) and the like, and antimony-doped SnO ₂ (refractive index) for the purpose of preventing dust from being imparted with an antistatic effect. n = 1.95), ITO (refractive index n = 1.95), SnO ₂ doped with phosphorus ( Oriritsu n = 1.75 to 1.85), antimony pentoxide (refractive index n = 2.04) or metal oxide particulates, such as, metal fine particles are preferably exemplified. For the purpose of obtaining a high refractive index layer, Al ₂ O ₃ (refractive index n = 1.63), La ₂ O ₃ (refractive index n = 1.95), ZrO ₂ (refractive index n = 2.05). High refractive index fine particles such as Y ₂ O ₃ (refractive index n = 1.87) are also preferred.

Further, SiO _2, Al ₂ O _3, or the above can also be used for improving the hardness of the hard coat layer.
The fine particles may have been surface-treated with a silane coupling agent, a titanate coupling agent, a fatty acid, a surfactant, or the like. For example, SiO ₂ whose surface is treated with a silane coupling agent is preferably used. The silane coupling agent can be used without particular limitation, but an agent having a (meth) acryloyl group as a functional group is preferable. Examples of such silane coupling agents include commercially available “KBM-502”, “KBM-503”, “KBE-503”, and “KBM-5103” (trade names, all manufactured by Shin-Etsu Chemical Co., Ltd.). Etc. are preferred.

  These fine particles are used singly or in combination, and those in a colloidal form dispersed in a solvent or water are good in terms of dispersibility, and the particle size is usually about 1 to 100 nm. Preferably, the thickness is 5 to 60 nm.

As various additives, for the purpose of reducing the reflectance, fine particles having voids, that is, fine particles forming a structure in which gas is filled and / or a porous structure containing gas (hereinafter referred to as “hollow particles”) May also be used preferably. Also included are fine particles capable of forming a nanoporous structure inside and / or at least part of the surface depending on the form, structure, aggregated state, and dispersed state of the fine particles inside the film.
The material for the hollow particles may be either an inorganic material or an organic material, and examples thereof include metals, metal oxides, and resins, and it is particularly preferable to use silica fine particles. Specific examples of such hollow particles include composite oxide sols or hollow silica fine particles disclosed in JP-A Nos. 7-133105 and 2001-233611. Since the inorganic particles having such voids have high hardness, there is also an advantage that the layer strength of the hard coat layer is improved.

As various additives, it is also preferable to add an antistatic agent in order to impart antistatic properties and make it difficult for dust and the like to adhere to the surface. Antistatic agents include conductive polymers such as polythiophene and polyaniline, and various cationic compounds having cationic groups such as quaternary ammonium salts, pyridinium salts, and primary to tertiary amino groups; sulfonate groups, sulfate esters Anionic compounds having anionic groups such as bases, phosphate ester bases, phosphonate bases; amphoteric compounds such as amino acids and aminosulfate esters; nonionic compounds such as amino alcohols, glycerols, and polyethylene glycols; tin And organic metal compounds such as alkoxides of titanium and metal chelate compounds such as acetylacetonate salts thereof, and compounds obtained by increasing the molecular weight of the compounds listed above.
These antistatic agents can be used alone or in combination of two or more.

  As various additives, it is also preferable to add an antifouling agent in order to impart antifouling properties. By adding an antifouling agent, the surface energy of the optical layered body of the present invention can be reduced, making it difficult to get hydrophilic or lipophilic stains. Easy to remove. Examples of such an antifouling agent include a fluorine-based compound, a silicon-based compound, or a mixture thereof, and a compound having a fluoroalkyl group is particularly preferable. These antifouling agents preferably have one or more ionizing radiation-curable polymerizable unsaturated groups in the molecule. This is because when the unsaturated group is contained, repeated wiping is possible and the durability is excellent.

  Other various additives include a weather resistance improver, an abrasion resistance improver, a polymerization inhibitor, an infrared absorber, an ultraviolet absorber, an adhesion improver, an antioxidant, a leveling agent, a thixotropic agent, a cup A ring agent, a plasticizer, an antifoamer, etc. are mentioned.

The thickness of the hard coat layer at the portion where the frame print pattern and the protective print pattern are not provided is preferably 5 to 20 μm, more preferably 7 to 15 μm. It is preferable for the thickness of the hard coat layer to be in the above-mentioned range since excellent surface hardness performance can be obtained and the occurrence of curling and cracking due to curing shrinkage that occurs when curing is reduced.
Moreover, it is preferable that the thickness of the hard-coat layer on the protective printing pattern provided on the frame printing pattern is 3-15 micrometers, More preferably, it is 5-10 micrometers, Moreover, said frame printing pattern and protective printing pattern The thickness is smaller than the thickness of the hard coat layer in the portion where no is provided. It is preferable that the thickness of the hard coat layer on the protective printing pattern is within the above range because excellent surface hardness performance can be obtained and the occurrence of curling and cracking due to curing shrinkage that occurs when curing is reduced. Here, the thickness of the hard coat layer is, for example, an observation of the cross section of the optical layered body of the present invention with an electron microscope (SEM, TEM, STEM), and the measured value is an average value of measured values at arbitrary ten points. Can be adopted.

In addition, in order to impart antiglare properties as various additives, it is also preferable to add an antiglare agent to form a (non-glare) hard coat layer having antiglare properties. Preferred examples of the antiglare agent include translucent fine particles, and inorganic and organic materials can be used. Organic materials include styrene beads (refractive index n = 1.60), melamine beads (refractive index n = 1.57), acrylic beads (refractive index n = 1.50 to 1.53), and acrylic-styrene. Beads (refractive index n = 1.54 to 1.58), benzoguanamine beads, polycarbonate beads (refractive index n = 1.57), polyethylene beads (refractive index n = 1.50), silicon beads (refractive index n = 1) .42) and the like. Inorganic fine particles are preferably silica fine particles, amorphous silica fine particles, inorganic silica beads and the like.
These translucent fine particles can be used alone or in combination of a plurality of types such as those having different components, different shapes, and different particle size distributions.

When anti-glare agents are used as various additives, the interference fringes are not visible due to diffusion, and the impregnated layer, which tends to decrease in hardness, can be thinned. Hard coat properties are obtained. Therefore, in this case, the thickness of the hard coat layer in the portion where the frame print pattern and the protective print pattern are not provided is excellent in surface hardness performance, and is free from curling and cracking due to hardening shrinkage that occurs when hardening. From the viewpoint of reducing generation, the thickness is preferably 1 to 15 μm, more preferably 3 to 10 μm.
Further, the thickness of the hard coat layer on the protective print pattern provided on the frame print pattern is preferably 0.5 to 15 μm, more preferably 1 to 10 μm, and the above frame print pattern and The thickness is smaller than the thickness of the hard coat layer in the portion where the protective printing pattern is not provided. It is preferable that the thickness of the hard coat layer on the protective printing pattern is within the above range because excellent surface hardness performance can be obtained and the occurrence of curling and cracking due to curing shrinkage that occurs when curing is reduced.

(Impregnation layer)
The optical layered body of the present invention preferably has an impregnated layer at a portion where the light transmissive substrate and the hard coat layer are in contact with each other, and particularly uses triacetyl cellulose as a material constituting the light transmissive substrate, and a hard coat. It is preferable when the layer is a hard coat layer having no antiglare property (glare). When the impregnated layer is formed in the optical laminate of the present invention, a gradient can be formed in the change in refractive index at the interface between the light transmissive substrate and the hard coat layer. Interference fringes generated due to the difference in refractive index with the coating layer can be suppressed, and the adhesion is also improved.

  The impregnated layer is formed by, for example, impregnating a light transmissive substrate with a resin component of an ionizing radiation curable resin composition forming a hard coat layer, that is, at least one component such as the above-described monomer or oligomer. It is preferable to form in the part which a material and a hard-coat layer contact | connect. Here, among the resin components in the ionizing radiation curable resin composition, those having a lower molecular weight tend to be impregnated into the light transmissive substrate, and tend to be impregnated in the order of monomer and oligomer. Further, a polymer having a high molecular weight is difficult to impregnate or not impregnated.

In this invention, it is preferable to use said permeable solvent as a solvent in an ionizing-radiation-curable resin composition from a viewpoint which can obtain an impregnation layer more stably. This is because when the permeable solvent is used, the light-transmitting substrate easily dissolves or swells, and the resin component in the ionizing radiation-curable resin composition easily penetrates into the light-transmitting substrate. In addition, although the said permeable solvent osmose | permeates in this light transmissive base material, it does not remain | survive finally in a light transmissive base material.
The thickness of the impregnated layer is preferably 0.2 to 8 μm, more preferably 1 to 7 μm, and still more preferably 1 to 5 μm. When the thickness of the impregnated layer is within the above range, the generation of interference fringes is suppressed, and the occurrence of whitening is also suppressed. Here, the thickness of the impregnated layer can be measured by, for example, observing the cross section of the optical laminate of the present invention with a scanning electron microscope (SEM) or the like. More specifically, the optical layered body of the present invention is first embedded with a thermosetting resin, and an ultrathin section is produced with a microtome. The obtained ultrathin slice is immersed in OsO ₄ (osmium oxide) for several minutes and dyed. Further, carbon is vapor-deposited to prepare a sample for measuring the thickness of the impregnated layer. Next, the thickness of the impregnated layer can be measured using a scanning electron microscope (SEM), for example, under the conditions of acceleration voltage: 30 kV, emission current: 10 μA, and magnification: 50.

  When the hard coat layer is an antiglare (non-glare) hard coat layer, an impregnated layer is preferably provided from the viewpoint of improving the adhesion between the hard coat layer and the light-transmitting substrate. In this case, the thickness of the impregnated layer is preferably 0.01 to 0.5 μm, more preferably 0.02 to 0.25 μm. When the hard coat layer is an antiglare (non-glare) hard coat layer, interference fringes do not occur, so there is no need to provide an impregnation layer from the viewpoint of reducing the occurrence of interference fringes, only improvement in adhesion. This is because the hard coat layer may be thinner than a hard coat layer having no antiglare property (glare).

(Other layers)
In the optical layered body of the present invention, a low refractive index layer, a high refractive index layer, an antifouling layer, an antistatic layer, an antiglare layer, or the like may be provided as desired. These layers are preferably provided on the above hard coat layer, more preferably provided so that the low refractive index layer is the uppermost layer, and when providing the antifouling layer, the antifouling layer is the uppermost layer. It is preferable to provide as described above. Further, the low refractive index layer may be provided with antifouling properties at the same time.

  These low refractive index layer and high refractive index layer can be formed by a method such as vacuum deposition or sputtering using the above-described low refractive index fine particles or high refractive index fine particles, and more easily From the viewpoint of forming the resin, a resin composition in which these fine particles are dispersed in the binder resin using, as a binder resin, a curable resin, for example, an ionizing radiation curable resin preferably used in forming the hard coat layer described above. Is preferably formed by a known method. Further, for example, the low refractive index layer has a fluorine-containing compound such as the above fine particles, vinylidene fluoride copolymer or silicone-containing vinylidene fluoride copolymer, and has two or more reactive functional groups in one molecule. It may be formed using a curable resin composition preferably containing a fluorine-containing monomer having an erythritol skeleton and an ionizing radiation curable resin.

  The antifouling layer may be formed by a known method using, for example, a resin composition containing an antifouling agent as described above and an ionizing radiation curable resin that is preferably used when forming the hard coat layer. .

  Moreover, in the optical laminated body of this invention, an antistatic layer can also be provided as desired. The antistatic layer may be provided on the above hard coat layer, or may be provided between the light-transmitting substrate and the hard coat layer, and the installation order is not particularly limited.

  The antistatic layer is a known method using, for example, a resin composition containing an antistatic agent, an antifouling agent, or the like as described above and an ionizing radiation curable resin preferably used in forming the hard coat layer. May be formed.

(Method for producing optical laminate)
The method for producing the optical laminate of the present invention is not particularly limited as long as the optical laminate having the above-described configuration is obtained. For example, (a) a step of preparing a light-transmitting substrate, (b) a frame printing pattern, A step of preparing a resin composition for forming a protective printing pattern, a hard coat layer, and a refractive index layer, an antistatic layer, an antiglare layer, an antifouling layer, etc. provided as desired; (c) the outer periphery of the light transmissive substrate A step of forming a frame print pattern along (d) a step of covering the frame print pattern and forming a protective print pattern between the frame print pattern and the hard coat layer, and (e) A step of forming an uncured resin layer of an ionizing radiation curable resin composition on the entire surface so as to cover the light transmissive substrate and the protective printing pattern; (f) irradiating the uncured resin layer with ionizing radiation; Each step of providing a hard coat layer Manufacturing method having the are preferably mentioned.

In the step (b), the resin composition for each layer can be prepared by mixing and dispersing the components contained in each resin composition according to a general preparation method. The mixing and dispersion may be performed by a paint shaker or a bead mill.
In the steps (c) to (e), each layer may be formed by applying a resin composition for forming each layer. Examples of the application method include a dip coating method, an air knife coating method, a curtain coating method, and a roll. Coating method, wire bar coating method, gravure coating method, extrusion coating method, micro gravure coating method, roll coating method, extrusion method, spin coating method, spray method, die coating method, slide coating method, bar coating method, meniscus coater It can be selected from various methods such as a method, a screen printing method, and a speed coater method. Especially, it is preferable to employ | adopt a gravure coat method from a viewpoint of ensuring the smoothness of a hard-coat layer, or the precision of thickness for formation of the frame printing pattern of (c) process, and thickness is said predetermined | prescribed In order to obtain the range, it is preferable to print at least twice, and more preferably three times.

When a thermosetting resin is used as the curable resin, the curing treatment by heating is usually performed between the steps (c) to (e), or (f) before irradiation with ionizing radiation in the step, or It may be done later. The temperature condition and the treatment time may be appropriately determined according to the curable resin to be used, and the curing treatment method by heating may be performed by a known method.
In addition, when a permeable solvent is used as the solvent in the ionizing radiation curable resin composition, the ionizing radiation curable resin composition for forming the hard coat layer is applied before the ionizing radiation irradiation in the step (f). The uncured resin layer formed by coating is preferably subjected to a drying treatment under the conditions of, for example, drying temperature: 40 to 80 ° C., drying time: 20 to 70 seconds, and wind speed: 5 to 20 m / min. By performing the drying treatment under the above conditions, the solvent sufficiently permeates the light-transmitting substrate, stabilizes the thickness of the impregnated layer without variation, and facilitates adjustment to the above predetermined range. .

  In the step (f), the curing method of the uncured resin layer may be appropriately selected depending on the curable resin to be used. When an electron beam is used as the ionizing radiation, the acceleration voltage depends on the resin used and the thickness of the layer. Although it can select suitably, it is preferable to harden an uncured resin layer normally with an acceleration voltage of about 70-300 kV. In addition, in electron beam irradiation, the transmission capability increases as the acceleration voltage increases, so when using a base material that deteriorates due to the electron beam as the base material, the penetration depth of the electron beam and the thickness of the uncured resin layer By selecting an accelerating voltage so as to be substantially equal to each other, it is possible to suppress irradiation of an extra electron beam to the light-transmitting substrate, and to prevent deterioration of the light-transmitting substrate due to excess electron beams. Can be kept to a minimum.

The irradiation dose is preferably such that the crosslinking density of the curable resin forming the hard coat layer is saturated.
Further, the electron beam source is not particularly limited. For example, various electron beam accelerators such as a cockroft Walton type, a bandegraft type, a resonant transformer type, an insulated core transformer type, a linear type, a dynamitron type, and a high frequency type. Can be used.

When ultraviolet rays are used as the ionizing radiation, those containing ultraviolet rays having a wavelength of 190 to 380 nm are emitted. There is no restriction | limiting in particular as an ultraviolet-ray source, For example, a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, a carbon arc lamp, etc. are used. The irradiation dose in this case is preferably an amount at which the crosslinking density of the curable resin forming the hard coat layer is saturated, and may be appropriately selected depending on the thickness of the hard coat layer and the illuminance of ultraviolet rays. from the viewpoint of occurrence inhibit, and preferably 50 to 300 mJ / cm ^2, more preferably 100~250mJ / cm ^2. When a cellulose resin (particularly triacetyl cellulose resin) is used as the material constituting the light transmissive substrate, ultraviolet rays can be used as ionizing radiation because the material is likely to be deteriorated by electron beam irradiation. preferable.

  The optical layered body of the present invention thus obtained is capable of suppressing the occurrence of cracks in the frame print pattern, has excellent adhesion to the substrate, is thin, When a triacetyl cellulose base material is used as the transparent base material, generation of interference fringes is suppressed, so that a liquid crystal display (LCD), a plasma display (PDP), an inorganic and organic LED (Light-emitting diode) display, electronic paper It is suitably used as a protective sheet for polarizers used in displays, touch panels, etc.

[Polarizer]
The polarizing plate of this invention has a polarizer protective sheet, a polarizer, and the optical laminated body of this invention in order. In FIG. 4, the structural example of the polarizing plate of this invention is shown. In FIG. 4, the polarizing plate 11 of the present invention is provided with one surface of a polarizer 7 and the light-transmitting substrate 1 of the optical laminate 10 of the present invention via an adhesive layer 6, and the other surface. Has a configuration in which a polarizer protective sheet is provided. Usually, the polarizing plate of the present invention is provided on the display such that the polarizer protective sheet is on the image source side and the optical laminate of the present invention is on the viewer side.
As a method of providing the optical laminate of the present invention and the polarizer protective sheet on the polarizer, a method of forming the optical laminate and the polarizer protective sheet directly on the polarizer, an optical laminate, and the polarizer protective sheet Preferred is a method in which the above is prepared first and then bonded to the polarizer via an adhesive layer.

(Polarizer)
The polarizer used in the polarizing plate may be any polarizer as long as it has a function of transmitting only light having a specific vibration direction. In general, a PVA (polyvinyl alcohol) polarizer is preferably used.
Examples of PVA polarizers include hydrophilic polymers such as PVA films, partially formalized polyvinyl alcohol films, and ethylene-vinyl acetate copolymer partially saponified films, and two colors such as iodine and dichroic dyes. And uniaxially stretched by adsorbing the active substance. Among these, a polarizer composed of a PVA film and a dichroic substance such as iodine is preferably used. The thickness of these polarizers is not particularly limited, and is generally about 1 to 100 μm.

A PVA resin suitably used as a resin constituting the polarizer can be obtained by saponifying a polyvinyl acetate resin. Examples of the polyvinyl acetate resin include, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, copolymerization of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids.
The degree of saponification of the PVA-based resin is usually 85 to 100 mol%, preferably 98 to 100 mol%. This PVA-based resin may be further modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The degree of polymerization of the PVA resin is usually in the range of 1,000 to 10,000, preferably 1,500 to 10,000.

(Polarizer protection sheet)
In the polarizing plate of the present invention, the polarizer protective sheet is not particularly limited as long as it can protect the polarizer and has optical transparency, for example, the optical transparency of the optical laminate of the present invention. Triacetyl cellulose base material used in the base material, cellulose base materials other than triacetyl cellulose, for example, cellulose base materials such as diacetyl cellulose, acetyl butyl cellulose, cellophane, polyester base materials such as polyethylene terephthalate, polycarbonate base materials, cyclopolyolefins A base material, a polyamide base material, a polyimide base material, etc. are mentioned preferably.

  When using the polarizing plate of this invention for various displays, it is preferable to use what can provide refractive index anisotropy as a polarizer protective sheet. As such a sheet, a sheet having performance as a λ / 4 plate is preferably exemplified. Usually, the performance as a λ / 4 plate means to show a value of 1/4 of the wavelength of incident light, but in the present invention does not show a value of exactly 1/4, It also includes those showing values in the range of ± 10% of the quarter value. Further, when the polarizer protective sheet has the performance as a λ / 4 plate, the chromatic dispersion of the in-plane retardation value Re value of the sheet is more indicative of the reverse dispersion performance in which the Re value becomes smaller as the wavelength becomes shorter. preferable.

In addition, a surface treatment such as corona treatment, plasma treatment, low-pressure UV treatment, saponification treatment, or a method of forming an anchor layer on the surface of the polarizer protective sheet in contact with the polarizer to improve adhesion to the polarizer. The easy adhesion treatment can be applied, or an easy adhesion layer (primer layer) can be provided. Of these, a corona treatment, a method of forming an anchor layer, and a method of using these in combination are preferable.
The polarizer protective sheet may be the optical laminate of the present invention, that is, the polarizing plate of the present invention is at least one of the two sheets sandwiching the polarizer is the optical laminate of the present invention. Any of the two sheets sandwiching the polarizer may be the optical laminate of the present invention.

(Production method of polarizing plate)
The polarizing plate is, for example, a process of uniaxially stretching a PVA film as described above, a process of dyeing a PVA resin film with a dichroic dye, and adsorbing the dichroic dye, and a dichroic dye being adsorbed. The step of treating the PVA-based film with an aqueous boric acid solution, the step of washing with water after the boric acid aqueous solution treatment, and the uniaxially stretched PVA-based film on which these steps have been adsorbed and oriented are used as a polarizer, The optical layered body of the present invention is manufactured through a process of attaching the polarizer to one surface of the polarizer and the polarizer protective sheet to the other surface.

The optical laminate and the polarizer protective sheet can be attached by applying an adhesive on either or both sides of the optical laminate and the polarizer protective sheet or the polarizer. As the adhesive used for the adhesive layer, when the light-transmitting substrate is formed of a hygroscopic material such as triacetylcellulose, for example, a known PVA-based adhesive is preferably used. When the material is formed of a material having no hygroscopicity such as a polyester resin, an ultraviolet curable adhesive is preferably exemplified.
The thickness of the adhesive layer is preferably 0.01 to 1 μm, more preferably 0.03 to 0, because the adhesiveness of the optical laminate and the polarizer protective sheet is lowered when the thickness after drying becomes too thick. .5 μm.

  Next, an adhesive layer is formed on the surface subjected to the easy adhesion treatment as described above, and the polarizer, the optical laminate, and the polarizer protective sheet are bonded through the adhesive layer. Bonding can be performed with a roll laminator or the like. The heating drying temperature and drying time are appropriately determined according to the type of adhesive.

  The polarizing plate of the present invention uses an optical laminate in which the occurrence of cracks in the frame print pattern is suppressed and has excellent adhesion to a substrate, and is thin. When a triacetyl cellulose base material is used as the light transmissive base material in FIG. 1, since the generation of interference fringes is suppressed, a liquid crystal display (LCD), a plasma display (PDP), an inorganic and organic LED (Light-emitting diode) display, It is suitably used for displays and touch panels used for electronic paper. In these uses, the aspect of using the triacetyl cellulose base material as the light-transmitting base material and the hard coat layer having no antiglare property (glare) hard coat layer has the most remarkable effect of the present invention. Since it is obtained, this is a preferred embodiment.

[Image display device]
The image display device of the present invention comprises the optical laminate of the present invention or the polarizing plate of the present invention. As such an image display device, a non-self-luminous image display device such as a display used in a liquid crystal display (LCD) or electronic paper, or a plasma display (PDP), an inorganic and organic LED (Light-emitting diode) display. A self-luminous image display device such as is preferable.
The image display device of the present invention is not particularly limited in its configuration as long as the optical laminate or polarizing plate of the present invention is provided in any place of these image display devices. There is no restriction on appropriately using components provided as necessary for each display such as a retardation plate inserted between the polarizing plates as necessary.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by this example.
(Evaluation method)
(1) Evaluation of adhesiveness About the optical laminated bodies obtained in Examples and Comparative Examples, the number of original cut parts (10 × 10 = 100 squares, size of one square: 1 mm × 1 mm) by cross-cut cross cut test The state of the surface of the optical laminate after the adhesive tape was applied and peeled was evaluated according to the following criteria.
A: There were 95 or more squares that did not peel at all. B: 85 to 94 squares that did not peel at all. Δ: There were 75 to 84 squares that did not peel at all. There were less than 74 masses that did not peel at all (2) Evaluation of solvent resistance After applying a frame printing pattern on a light-transmitting substrate and heat-curing the same as in Examples and Comparative Examples After dropping several drops of methyl ethyl ketone and leaving it to dry, the surface was visually observed and evaluated according to the following criteria.
◎ No change ○ There are several cracks △ There are innumerable cracks × There are innumerable cracks and the appearance is whitened (3) Evaluation of interference fringes The surface opposite to the hard coat layer of the optical laminate obtained in Examples and Comparative Examples Then, a black tape for preventing back surface reflection was applied, the hard coat layer was illuminated with a Na lamp or a three-wavelength fluorescent lamp, and visually observed from the hard coat layer side, and the presence or absence of occurrence of interference fringes was evaluated.
◎ No interference fringes were generated. ○ Interference fringes were hardly generated. △ Interference fringes were slightly generated, but there was no practical problem. × Interference fringes were generated. (4) Measurement of transmission density of frame print pattern About the frame printing pattern of the optical laminated body obtained by the example and the comparative example, using a transmission densitometer ("X-Rite 361T (model number)", manufactured by X-Rite), the transmission density was measured with a 3 mm diameter aperture. It was measured. The transmission density was measured at three points at 100 mm intervals on the printing surface side of the frame printing pattern in the vertical and horizontal directions, and the average value was obtained.
(5) Measurement of thickness of frame print pattern and protective print pattern About the frame print pattern and the protective print pattern of the optical laminate obtained in the examples and comparative examples, a digital thickness gauge ("Digimatic indicator ID-H0530 (model number ) ”, Manufactured by Mitutoyo Corporation). The thickness of each pattern is measured at three points at 100 mm intervals in the vertical and horizontal directions on the printed surface of the printed pattern and on the surface where the pattern in the vicinity of the printed pattern is not printed. The difference between the average value and the average value of the thickness of the surface on which the pattern was not printed was used as the thickness of the printed pattern.

Example 1
A light-transmitting substrate (triacetylcellulose film, thickness: 60 μm, “TD60UL (model number)”, manufactured by Fuji Film Co., Ltd.) is prepared, and the following two-component curability is provided on one surface of the substrate. Black frame printing pattern resin composition A (“VM-D795 Black (trade name), manufactured by Dainichi Seika Kogyo Co., Ltd.”) was printed twice by the gravure printing method, and heated in a 70 ° C. heat oven for 60 seconds. Heating and drying to form a frame printing pattern with a thickness of 3 μm and a width of 12 mm, and the following two-part curable resin composition A (“VM-D medium (trade name), “Daiichi Seika Kogyo Co., Ltd.”) was applied by gravure printing, dried in a heating oven at a temperature of 70 ° C. for 60 seconds to form a protective printing pattern having a thickness of 1.5 μm, and 40 ° C. In the oven for 24 hours A frame print pattern and protecting printed pattern was cured. Here, the contact width between the protective printing pattern and the light-transmitting substrate was 1 mm. Next, the following ultraviolet curable resin composition is applied by a gravure coating method to form an uncured resin layer, heated in a heat oven at 70 ° C. for 60 seconds to volatilize methyl ethyl ketone as a solvent, and then irradiated with ultraviolet rays. Irradiation was performed so that the total integrated amount was 150 mJ / cm ² to form a hard coat layer having a thickness of 10 μm, and an optical laminate as shown in FIG. 1 was obtained. Said evaluation was performed about the obtained optical laminated body. The evaluation results are shown in Table 1.
(Resin composition A for frame printing pattern)
Acrylic polyol resin (weight average molecular weight: 60000): 16 parts by mass Vinyl chloride-vinyl acetate copolymer (weight average molecular weight: 50000): 6 parts by mass carbon black (primary average particle size: 20 nm): 9 parts by mass polyisocyanate curing Agent ("PTC-L8 reforming agent (trade name)", manufactured by Dainichi Seika Kogyo Co., Ltd.): 7 parts by mass Solvent (methyl ethyl ketone / toluene = 5/5): 62 parts by mass (resin composition A for protective printing pattern) )
Acrylic polyol resin (weight average molecular weight: 60000): 18 parts by mass vinyl chloride-vinyl acetate copolymer (weight average molecular weight: 50000): 7 parts by mass polyisocyanate curing agent ("PTC-L8 reforming agent (trade name)" , Manufactured by Dainichi Seika Kogyo Co., Ltd.): 7 parts by mass Solvent: (methyl ethyl ketone / toluene = 5/5): 68 parts by mass (UV curable resin composition)
10-functional urethane acrylate (“UV-1700B (trade name)”, manufactured by Nippon Gosei Kogyo Co., Ltd., weight average molecular weight: 2000): 50 parts by mass trifunctional polyester acrylate oligomer (“M9050 (trade name)”, Toa Gosei Co., Ltd. Made by company, weight average molecular weight: 400 to 430): 50 parts by mass photopolymerization initiator (“Irgacure 184 (product name)”, manufactured by BASF): 4 parts by mass methyl ethyl ketone: 100 parts by mass leveling agent (“F477 (model number)”) , Manufactured by DIC Corporation, nonionic fluorine-containing group / hydrophilic group / lipophilic group-containing oligomer): 0.2 part by mass

Example 2
In Example 1, the resin composition A for frame printing pattern was used as the resin composition B for frame printing pattern formation (“SS 805 ink (trade name), manufactured by Dainichi Seika Kogyo Co., Ltd.”). An optical laminate was obtained in the same manner as in Example 1 except that the thickness of the frame print pattern was 4.5 μm by rubbing 3 times. Said evaluation was performed about the obtained optical laminated body. The evaluation results are shown in Table 1.
(Resin Composition B for Forming Frame Print Pattern)
Urethane resin (weight average molecular weight: 50000): 13 parts by mass carbon black (primary average particle size: 20 nm): 13 parts by mass polyisocyanate curing agent (“Ramic B Hardener (trade name)”, manufactured by Dainichi Seika Kogyo Co., Ltd.) : 2 parts by mass Solvent: (Methyl ethyl ketone / toluene / isopropyl alcohol = 4/4/2): 72 parts by mass

Example 3
In Example 1, the resin composition A for forming a frame printing pattern was used as the following resin composition C for forming a frame printing pattern (“NB300 805 black (trade name), manufactured by Dainichi Seika Kogyo Co., Ltd.”). An optical laminate was obtained in the same manner as in Example 1 except that the product C was printed three times to change the thickness of the frame print pattern to 4.5 μm. Said evaluation was performed about the obtained optical laminated body. The evaluation results are shown in Table 1.
(Resin Composition C for Forming Frame Print Pattern)
Urethane resin (weight average molecular weight: 50000): 11 parts by mass Vinyl chloride-vinyl acetate copolymer (weight average molecular weight: 50000): 3 parts by mass carbon black (primary average particle size: 20 nm): 14 parts by mass polyisocyanate curing agent ("Lamic B Hardener (trade name)", manufactured by Dainichi Seika Kogyo Co., Ltd.): 2 parts by mass Solvent: (methyl ethyl ketone / toluene / isopropyl alcohol = 4/4/2): 70 parts by mass

Example 4
In Example 1, the frame printing pattern forming resin composition A was used as the frame printing pattern forming resin composition C used in Example 3, and the resin composition C was rubbed three times to reduce the thickness of the frame printing pattern. The protective printing pattern forming resin composition A was 4.5 μm, and the following protective printing pattern forming resin composition B (“TM-VMAC (trade name), manufactured by Dainichi Seika Kogyo Co., Ltd.”) was used. An optical laminate was obtained in the same manner as Example 1. Said evaluation was performed about the obtained optical laminated body. The evaluation results are shown in Table 1.
(Resin composition B for protective printing pattern)
Acrylic polyol resin (weight average molecular weight: 80000): 25 parts by mass polyisocyanate curing agent (“PTC-L8 reforming agent (trade name)”, manufactured by Dainichi Seika Kogyo Co., Ltd.): 7 parts by mass Solvent: (methyl ethyl ketone / toluene = 5/5): 68 parts by mass

Example 5
An optical laminate in the same manner as in Example 1 except that the light-transmitting substrate in Example 1 was a polyethylene terephthalate resin substrate (“A4300 (trade name)”, manufactured by Toyobo Co., Ltd., thickness: 50 μm). Got. Said evaluation was performed about the obtained optical laminated body. The evaluation results are shown in Table 1.

Example 6
In Example 1, an optical laminate was obtained in the same manner as in Example 1 except that the solvent contained in the ultraviolet curable resin composition was changed from methyl ethyl ketone to methyl isobutyl ketone. Said evaluation was performed about the obtained optical laminated body. The evaluation results are shown in Table 1.

Comparative Example 1
In Example 1, the optical laminated body was obtained like Example 1 except not having provided the protective printing pattern. Said evaluation was performed about the obtained optical laminated body. The evaluation results are shown in Table 1.

Comparative Example 2
In Example 1, an optical laminate was obtained in the same manner as in Example 1 except that the protective printing pattern-forming resin composition A was changed to the following protective printing pattern-forming resin composition C not containing an acrylic polyol resin. . Said evaluation was performed about the obtained optical laminated body. The evaluation results are shown in Table 1.
(Resin composition C for protective printing pattern)
Urethane resin (weight average molecular weight: 50000): 25 parts by mass polyisocyanate curing agent (“Ramic B Hardener (trade name), manufactured by Dainichi Seika Kogyo Co., Ltd.): 5 parts by mass Solvent: (methyl ethyl ketone / toluene = 5/5 ): 70 parts by mass

  It was confirmed that the optical laminates of the examples were excellent in all evaluations of adhesion, solvent resistance, and interference fringes. On the other hand, in Comparative Example 1 in which no protective printing pattern was provided, the adhesion between the frame printing pattern and the light-transmitting substrate was poor, and a sufficient effect was not shown in terms of solvent resistance. In Comparative Example 2 in which acrylic polyol was not used as the resin in the product, excellent adhesion could not be obtained. Moreover, since the optical laminated body of Examples 1-4 was thicker in the impregnation layer than the optical laminated body of Examples 5 and 6, it was confirmed that it is excellent in the point of evaluation of interference fringes.

  The optical layered body of the present invention suppresses the occurrence of cracks in the frame print pattern, has excellent adhesion to the substrate, is thin, and has triacetyl cellulose as a light-transmitting substrate. When the base material is used, the generation of interference fringes is suppressed, so a liquid crystal display (LCD), a plasma display (PDP), an inorganic and organic LED (Light-emitting diode) display, a display or touch panel used for electronic paper, etc. It is suitably used as a protective sheet for a polarizer used in the above.

DESCRIPTION OF SYMBOLS 1 Light transmissive base material 2 Frame printing pattern 3 Protective printing pattern 4 Hard coat layer 5 Impregnation layer 6 Adhesive layer 7 Polarizer 8 Polarizer protective sheet 10 Optical laminated body 11 Polarizing plate

Claims (16)

  On one surface of the light transmissive substrate, a frame print pattern, a protective print pattern, and a hard coat layer are provided, and the frame print pattern is provided along the outer periphery of the light transmissive substrate. A print pattern is provided so as to cover the frame print pattern and between the frame print pattern and the hard coat layer, and the hard coat layer covers the light transmissive substrate and the protective print pattern. The frame printing pattern is a cured product of a curable resin composition containing a colorant and a curable resin, and the hard coat layer is a cured product of an ionizing radiation curable resin composition, An optical laminate in which the protective printing pattern is a cured product of a curable resin composition containing at least an acrylic polyol resin.   The optical laminate according to claim 1, wherein the acrylic polyol resin has a weight average molecular weight of 10,000 to 100,000.   The optical layered product according to claim 1 or 2 whose glass transition point of said acrylic polyol resin is 50-110 ° C.   The optical laminate according to any one of claims 1 to 3, wherein the protective printing pattern is a cured product of a curable resin composition containing an acrylic polyol resin and a vinyl chloride-vinyl acetate copolymer.   The optical laminate according to claim 4, wherein the blending ratio (mass ratio) of the acrylic polyol resin and the vinyl chloride-vinyl acetate copolymer is 9: 1 to 5: 5.   The optical laminate according to any one of claims 1 to 5, wherein the material constituting the light transmissive substrate is triacetylcellulose, and the impregnated layer is provided in a portion where the light transmissive substrate and the hard coat layer are in contact with each other. body.   The optical laminate according to claim 6, wherein the impregnated layer has a thickness of 0.2 to 8 μm.   The optical laminate according to any one of claims 1 to 7, wherein a transmission density of the frame print pattern is 3 to 8.   The optical layered product according to any one of claims 1 to 8, wherein the colorant is a color pigment.   The optical laminate according to claim 9, wherein the color pigment contains carbon black.   The optical laminate according to claim 9 or 10, wherein the color pigment is carbon black having an average primary particle size of 5 to 70 nm.   The optical laminated body according to any one of claims 1 to 10, wherein the ionizing radiation curable resin contained in the ionizing radiation curable resin composition is an ultraviolet curable resin.   The polarizing plate which has a polarizer protective sheet, a polarizer, and the optical laminated body in any one of Claims 1-12 in order.   The polarizing plate according to claim 13, wherein the polarizer protective sheet has a performance as a λ / 4 plate.   The polarizing plate according to claim 13 or 14, wherein the polarizer protective sheet has reverse dispersion characteristics.   An image display device comprising the optical laminate according to any one of claims 1 to 12 or the polarizing plate according to any one of claims 13 to 15.