JP7392278B2 - Method for manufacturing liquid crystal compound laminate and method for inspecting liquid crystal compound layer - Google Patents

Description

The present invention relates to a method for manufacturing a laminate having a liquid crystal compound layer (liquid crystal compound layer laminate), and more particularly to a method for manufacturing a liquid crystal compound layer laminate by continuously providing a liquid crystal compound layer on an object by a transfer method. .

In recent years, image display devices are required to be thinner, and each member of the image display device is also required to be thinner. Polarizing plates used in liquid crystal display devices and circularly polarizing plates used for antireflection in organic EL display devices are no exception and are required to be made thinner.

Retardation films used in circularly polarizing plates and the like have conventionally been made by stretching resin films such as triacetyl cellulose resin (TAC), cyclic polyolefin (COP), or acrylic to give a retardation effect, or films made from these materials. Films with a layer of oriented liquid crystal compounds on the surface have been used, but there has been a limit to how thin they can be made. Therefore, instead of a method of laminating retardation films, a method of forming a retardation layer on a releasable film, transferring this retardation layer to an object such as a polarizer, and then laminating the retardation layer has been used. (Patent Document 1, etc.).

As release films for transferring these retardation layers, transparent films without retardation, such as TAC films, COP films, and acrylic films, have been used.
By using a transparent film without retardation as such a release film, with the retardation layer laminated on the release film, polarized light is irradiated from one side and received on the other side, changing the position of the retardation layer. The state of phase difference can be inspected. As a result, if the retardation layer cannot be obtained as designed due to an abnormality in the process, the abnormality can be detected before it is transferred to the target object, and it is possible to avoid producing a large number of non-standard products. This risk can be avoided.

However, the method of using such a releasable film results in the film being discarded after use or being recycled as a resin raw material, which places a large burden on the environment, requires energy, and is economically unsatisfactory. In other words, it was not necessarily desirable.

Japanese Patent Application Publication No. 2017-146616

The present invention has been made against the background of such problems of the prior art. That is, an object of the present invention is to provide an economically excellent method for manufacturing a liquid crystal compound layer laminate that reduces waste and energy requirements in manufacturing the liquid crystal compound layer laminate. Furthermore, it is an object of the present invention to provide a manufacturing method and an inspection method that can inspect a liquid crystal compound layer before transferring the liquid crystal compound layer to an object, and can also avoid the risk of manufacturing non-standard products in large quantities. .

The present inventor has completed the present invention as a result of intensive studies to achieve the above object.
Representative examples of the present invention are as follows.
Item 1.
A method for producing a liquid crystal compound layer laminate, comprising at least the following steps (a) and (b).
(a) Step of providing a liquid crystal compound layer on the specularly reflective surface of an endless belt having a specularly reflective surface; (b) By transferring the liquid crystal compound layer provided on the specularly reflective surface to the transfer target, Step 2 of obtaining a liquid crystal compound layer laminate in which a liquid crystal compound is laminated on a transfer target.
Item 2. The method for producing a liquid crystal compound layer laminate according to Item 1, wherein the endless belt is a metal belt.
Item 3.
Item 3. The method for producing a liquid crystal compound layer laminate according to Item 1 or 2, wherein the liquid crystal compound layer is a retardation layer.
Item 4.
Item 3. The method for producing a liquid crystal compound layer laminate according to Item 3, wherein the transfer target includes a polarizer.
Item 5.
5. The method for producing a liquid crystal compound layer laminate according to item 3 or 4, wherein the retardation layer is a λ/4 retardation layer.
Item 6.
6. The method for producing a liquid crystal compound layer laminate according to item 5, wherein the retardation layer laminate liquid crystal compound layer laminate is a circularly polarizing plate.
Section 7.
A method for inspecting a liquid crystal compound layer provided on the surface of an endless belt, which includes a step (a) of irradiating polarized light from the liquid crystal compound layer side of the endless belt, and a step (b) of receiving the reflected polarized light. A method for inspecting a liquid crystal compound layer on an endless belt provided with a compound layer.

According to the present invention, when manufacturing a liquid crystal compound layer laminate, it is possible to reduce waste and required energy, and to manufacture a liquid crystal compound layer laminate using an economically superior method. Furthermore, the liquid crystal compound layer can be inspected before it is transferred to the object, and the risk of producing a large number of non-standard products can be avoided.

This is an example of a photo-alignment control layer type transfer equipment equipped with an endless belt. Figure (a) is an example of a rubbing orientation control layer type transfer facility equipped with an endless belt (endless belt portion only), and Figure (b) is a view of the rubbing roll portion viewed diagonally from above. This is another example of a photo-alignment control layer type transfer equipment equipped with an endless belt (only the endless belt portion). This is another example of a photo-alignment control layer type transfer equipment equipped with an endless belt (only the endless belt portion). This is another example of a photo-alignment control layer type two-layer simultaneous transfer facility equipped with an endless belt (only the endless belt portion). This is an example of a transfer part of a transfer equipment using an optical adhesive sheet and equipped with an endless belt. This is an example of inspection equipment for a retardation layer on an endless belt.

(endless belt)
The endless belt used in the present invention is not particularly limited as long as it can generally constitute an endless belt, and may include resin- or rubber-impregnated fabric, fiber-reinforced resin, fiber-reinforced rubber, resin sheets, resin films, metals, etc. Among them, metal is preferable in terms of strength, dimensional stability against heating and tension, heat resistance, etc. Examples of metals include iron, aluminum, copper, titanium, and alloys thereof. Examples of these alloys include stainless steel, duralumin, magnalium, aluminum bronze, brass, cupronickel, bronze, and stainless steel, with stainless steel being preferred.

It is necessary that at least one side of the endless belt has a specular reflective surface. Note that hereinafter, a specularly reflective surface may be simply referred to as a reflective surface.
If the endless belt is made of metal (metal belt), a method for making the surface mirror-like may include mirror-polishing.

Further, the surface of the metal belt is preferably plated to further improve specularity and to improve releasability from the retardation layer. The plating process includes electrolytic plating, electroless plating, etc., and vapor deposition, sputtering, CVD, etc. are also preferable.

The plating is preferably non-corrosive, and includes gold, silver, chromium, nickel, zinc, cobalt, tin, and chromium-based plating, with nickel, cobalt, and chromium-based plating being preferred. Nickel, cobalt, and chromium-based substances include not only single substances but also nickel-chromium, nickel-cobalt, nickel-tin, nickel-tin-cobalt, nickel-phosphorous, nickel-boron, nickel-tungsten, nickel-iron, Preferred examples include nickel-zinc. Further, in order to adjust wear resistance, wettability, lubricity, etc., it is also preferable to use a composite plating in which fine particles of SiC, cBN, PTFE, etc. are eutectoid.

Methods for making a non-metallic endless belt a specularly reflective surface include methods such as laminating metal foil, vapor deposition on the surface, and forming a thin metal film layer by sputtering, etc., each method suitable for each method. The surface can be made smooth and mirror-like. Note that the metals used are preferably those listed for the metal belt or those listed for the plating.

The lower limit of the roughness Ra of the reflective surface is preferably 1 nm, more preferably 1.5 nm, and even more preferably 2.0 nm. The upper limit of the roughness Ra of the reflective surface is preferably 30 nm, more preferably 25 nm, even more preferably 20 nm, particularly preferably 15 nm, and most preferably 10 nm.

The lower limit of the ten-point average surface roughness Rzjis of the reflective surface is preferably 5 nm, more preferably 10 nm, and even more preferably 13 nm. The upper limit of the ten-point average surface roughness Rzjis of the reflective surface is preferably 200 nm, more preferably 150 nm, even more preferably 120 nm, particularly preferably 100 nm, and most preferably 80 nm.

The lower limit of the maximum height Rz (maximum peak height Rp+maximum valley depth Rv) of the reflective surface is preferably 10 nm, more preferably 15 nm, and even more preferably 20 nm. The upper limit of the maximum height Rz of the reflective surface is preferably 300 nm, more preferably 250 nm, even more preferably 150 nm, particularly preferably 120 nm and most preferably 100 nm.

The specular reflective surface preferably has a lower limit of gloss of 200%, more preferably 300%, still more preferably 400%, particularly preferably 450%. Most preferably it is 500%. By setting the gloss level above the above level, a preset alignment state can be obtained when the liquid crystal compound is aligned using polarized ultraviolet rays. Furthermore, accuracy when inspecting the alignment state of the liquid crystal compound layer can be ensured.

Glossiness is a value measured based on the specular glossiness measurement method of JIS Z8741 (1997) on a glass surface with a refractive index of 1.567, with a reflectance of 10% at an incident angle of 60° and a glossiness of 100 (%). It is.

If the reflective surface has poor releasability from the retardation layer, a release layer may be provided. The release layer is preferably transparent so as to maintain specular reflection. Examples of the release layer include resins, metal oxides, and the like. Examples of the resin include alkyd resins, amino resins, olefin resins, long-chain acrylate copolymerized acrylic resins, silicone resins, silicone-modified acrylic resins, and fluororesins. The release layer of these resins is preferably provided by coating.

Examples of metal oxides include aluminum oxide, silicon oxide, zinc oxide, magnesium oxide, tin oxide, and mixtures thereof. These methods include dry processes such as vapor deposition, sputtering, and CVD, and methods such as enameling, in which powder is applied to the surface and then heated and melted.

The thickness of the release layer varies depending on the type, but is preferably 5 nm to 1 mm, and preferably 10 nm to 0.5 mm.
Preferably, the release layer is isotropic in refractive index. The retardation of the release layer is preferably 100 nm or less, more preferably 50 nm or less.
When a release layer is provided, the surface of the release layer has the same roughness as the reflective surface described above.

(liquid crystal compound layer)
In the present invention, a liquid crystal compound layer is provided on the reflective surface of the endless belt as described above, and this layer is transferred to an object.
Although the method of providing the liquid crystal compound layer is not particularly limited, it is preferable to provide the liquid crystal compound by coating.

The liquid crystal compound layer is preferably a retardation layer, a polarizing layer, or a circularly polarized light reflecting layer. In order to make a liquid crystal compound layer into a polarizing layer with excellent polarization properties, an appropriate retardation layer, and a retardation layer with a circularly polarized light reflecting layer, it is necessary to orient the liquid crystal compound. Methods for alignment include a method in which the liquid crystal compound is applied and then irradiated with polarized ultraviolet rays to directly align the liquid crystal compound, a method in which an alignment control force is applied to the reflective surface of the endless belt and the liquid crystal compound is aligned by the alignment control force, There is a method in which an alignment control layer is provided on an endless belt as a lower layer of the liquid crystal compound layer, and the liquid crystal compound is aligned by the alignment control force of the alignment control layer.

In the method of directly aligning the liquid crystal compound by irradiating it with polarized ultraviolet rays after applying the liquid crystal compound, a paint containing a liquid crystal compound having double bonds is applied to the reflective surface of the endless belt, and after removing the solvent if necessary, polarized ultraviolet light is applied. The liquid crystal compound is irradiated with ultraviolet rays to align the liquid crystal compound, and the double bonds are reacted to fix the alignment.

(Orientation control layer)
Also preferred is a method in which an alignment control layer is provided on the reflective surface of the endless belt, and a liquid crystal compound layer is provided on the alignment control layer. In the present invention, the alignment control layer and the liquid crystal compound layer may be collectively referred to as the liquid crystal compound layer instead of the liquid crystal compound layer alone. As the alignment control layer, any alignment control layer may be used as long as it can bring the liquid crystal compound layer into a desired alignment state, but a rubbed alignment control layer obtained by rubbing a resin coating film, A suitable example is a photo-alignment control layer that orients molecules by irradiating polarized light to produce an alignment function.

(Rubbing treatment orientation control layer)
Polyvinyl alcohol and derivatives thereof, polyimide and derivatives thereof, acrylic resins, polysiloxane derivatives, and the like are preferably used as polymer materials for the alignment control layer formed by rubbing treatment.

The method for forming the rubbed orientation control layer will be described below. First, a rubbed orientation control layer coating solution containing the above polymer material is applied onto the reflective surface of an endless belt, and then heated and dried to obtain an orientation control layer before rubbing. The alignment control layer coating liquid may contain a crosslinking agent.

As the solvent for the rubbing treatment orientation control layer coating solution, any solvent can be used without any restriction as long as it dissolves the polymer material. Specific examples include water, alcohols such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, and cellosolve; ester solvents such as ethyl acetate, butyl acetate, and gamma butyrolactone; acetone, methyl ethyl ketone, cyclopentanone, and cyclohexanone. , aromatic hydrocarbon solvents such as toluene or xylene, and ether solvents such as tetrahydrofuran or dimethoxyethane. These solvents may be used alone or in combination.

The concentration of the rubbing treatment orientation control layer coating solution can be adjusted as appropriate depending on the type of polymer and the thickness of the orientation control layer to be produced, but it is preferably 0.2 to 20% by mass expressed as solid content concentration, A range of 0.3 to 10% by weight is particularly preferred. As a coating method, a known method such as a gravure coating method, a die coating method, a bar coating method, an applicator method, or a printing method such as a flexographic method is employed.

The temperature for heating and drying depends on the material of the endless belt, but is preferably in the range of 30 to 170°C, more preferably 50 to 150°C, still more preferably 70 to 130°C. When the drying temperature is low, it becomes necessary to take a long drying time, which may result in poor productivity. If the drying temperature is too high, depending on the material, the endless belt may expand or shrink due to heat, making it impossible to achieve the designed optical function or causing poor flatness. The heat drying time may be, for example, 0.5 to 30 minutes, more preferably 1 to 20 minutes, and even more preferably 2 to 10 minutes.

The thickness of the rubbed orientation control layer is preferably 0.01 to 10 μm, more preferably 0.05 to 5 μm, particularly preferably 0.1 μm to 1 μm.

Next, a rubbing process is performed. The rubbing treatment can generally be carried out by rubbing the surface of the rubbed orientation control layer after coating in a certain direction with paper or cloth. Generally, the surface of the orientation control layer is rubbed using a rubbing roller made of a raised cloth made of fibers such as nylon, polyester, or acrylic. In order to provide a liquid crystal compound layer oriented in a predetermined direction oblique to the circumferential direction (running direction) of the endless belt, it is necessary to set the rubbing direction of the alignment control layer at an angle corresponding to the direction. The angle can be adjusted by adjusting the angle between the rubbing roller and the endless belt, and by adjusting the conveyance speed of the endless belt and the rotation speed of the roller.

(Photo alignment control layer)
A photo-alignment control layer is a layer in which a coating solution containing a polymer or monomer having a photo-reactive group and a solvent is applied to the reflective surface of the endless belt, and the layer is irradiated with polarized light, preferably polarized ultraviolet rays, to exert an alignment control force. Refers to the applied alignment film. The photoreactive group refers to a group that exhibits liquid crystal alignment ability upon irradiation with light. Specifically, it is one that induces the orientation of molecules by irradiation with light, or causes a photoreaction that is the origin of the liquid crystal alignment ability, such as an isomerization reaction, a dimerization reaction, a photocrosslinking reaction, or a photodecomposition reaction. be. Among the photoreactive groups, those that cause a dimerization reaction or a photocrosslinking reaction are preferable because they have excellent alignment properties and maintain the liquid crystal state of the λ/4 retardation layer. The photoreactive group capable of causing the above reaction is preferably an unsaturated bond, particularly a double bond, and a group consisting of a C=C bond, a C=N bond, a N=N bond, or a C=O bond. Particularly preferred are groups having at least one selected from the following.

Examples of the photoreactive group having a C═C bond include a vinyl group, a polyene group, a stilbene group, a stilbazole group, a stilbazolium group, a chalcone group, and a cinnamoyl group. Examples of the photoreactive group having a C=N bond include groups having structures such as an aromatic Schiff base and an aromatic hydrazone. Examples of the photoreactive group having an N=N bond include an azobenzene group, an azonaphthalene group, an aromatic heterocyclic azo group, a bisazo group, a formazan group, and those having an azoxybenzene as a basic structure. Examples of the photoreactive group having a C═O bond include a benzophenone group, a coumarin group, an anthraquinone group, and a maleimide group. These groups may have substituents such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group, and a halogenated alkyl group.

Among them, a photoreactive group that can cause a photodimerization reaction is preferable, and a cinnamoyl group and a chalcone group are preferable, and a photoalignment layer that requires a relatively small amount of polarized light irradiation for photoalignment and has excellent thermal stability and stability over time is preferable. It is preferred because it is easy to obtain. Furthermore, as the polymer having a photoreactive group, one having a cinnamoyl group such that the end portion of the polymer side chain has a cinnamic acid structure is particularly preferable. Examples of the structure of the main chain include polyimide, polyamide, (meth)acrylic, polyester, and the like.

Specific orientation control layers include, for example, JP-A No. 2006-285197, JP-A No. 2007-76839, JP-A No. 2007-138138, JP-A No. 2007-94071, and JP-A No. 2007-121721. , JP 2007-140465, JP 2007-156439, JP 2007-133184, JP 2009-109831, JP 2002-229039, JP 2002-265541, Orientation described in JP-A No. 2002-317013, JP-A No. 2003-520878, JP-A No. 2004-529220, JP-A No. 2013-33248, JP-A No. 2015-7702, JP-A No. 2015-129210 An example is a control layer.

As the solvent for the coating liquid for forming a photo-alignment control layer, any solvent can be used without any restriction as long as it dissolves the polymer and monomer having a photo-reactive group. Specific examples include those mentioned in the rubbing treatment method for forming an alignment control layer. It is also preferable to add a photopolymerization initiator, a polymerization inhibitor, and various stabilizers to the coating liquid for forming a photoalignment control layer. Furthermore, a polymer other than the polymer having a photoreactive group and a monomer having no photoreactive group that can be copolymerized with the monomer having a photoreactive group may be added.

The concentration, coating method, and drying conditions of the coating solution for forming a photo-alignment control layer can be exemplified by those mentioned in the rubbing treatment method for forming the alignment control layer. The thickness is also the same as the preferred thickness of the rubbed orientation control layer.

The polarized light is irradiated from the direction of the surface of the optical alignment control layer before alignment.
The wavelength of the polarized light is preferably in a wavelength range in which a photoreactive group of a polymer or monomer having a photoreactive group can absorb light energy. Specifically, ultraviolet light having a wavelength in the range of 250 to 400 nm is preferable. Examples of polarized light sources include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, and ultraviolet lasers such as KrF and ArF, with high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps being preferred. .

Polarized light can be obtained, for example, by passing the light from the light source through a polarizer. By adjusting the polarization angle of the polarizer, the direction of polarization can be adjusted. Examples of the polarizer include polarizing filters, polarizing prisms such as Glan-Thompson and Glan-Taylor, and wire grid type polarizers. Preferably, the polarized light is substantially parallel light.

By adjusting the angle of the polarized light to be irradiated, the direction of the alignment regulating force of the optical alignment control layer can be arbitrarily adjusted.

The irradiation intensity varies depending on the type and amount of the polymerization initiator and resin (monomer), but is preferably from 10 to 10,000 mJ/cm ² and more preferably from 20 to 5,000 mJ/cm ² based on 365 nm.

(liquid crystal compound layer)
The liquid crystal compound layer is not particularly limited as long as the liquid crystal compound is oriented. Specific examples include a polarizing film (polarizer) containing a liquid crystal compound and a dichroic dye, a retardation layer containing a rod-shaped or discotic liquid crystal compound, and a circularly polarized light reflecting layer containing a liquid crystal compound and a chiral agent. .

(polarizing film)
The polarizing film has a function of passing polarized light in only one direction, and contains a dichroic dye.

(dichroic dye)
A dichroic dye refers to a dye that has a property that the absorbance in the long axis direction of the molecule is different from the absorbance in the short axis direction.

The dichroic dye preferably has an absorption maximum wavelength (λMAX) in the range of 300 to 700 nm. Examples of such dichroic dyes include acridine dyes, oxazine dyes, cyanine dyes, naphthalene dyes, azo dyes, and anthraquinone dyes, among which azo dyes are preferred. Examples of azo dyes include monoazo dyes, bisazo dyes, trisazo dyes, tetrakisazo dyes, and stilbene azo dyes, with bisazo dyes and trisazo dyes being preferred. The dichroic dyes may be used alone or in combination, but in order to adjust the color tone (achromatic color), it is preferable to combine two or more types. In particular, it is preferable to combine three or more types. In particular, it is preferable to combine three or more types of azo compounds.

Preferred azo compounds include dyes described in JP-A No. 2007-126628, JP-A No. 2010-168570, JP-A No. 2013-101328, and JP-A No. 2013-210624.

It is also preferred that the dichroic dye is a dichroic dye polymer incorporated into the side chain of a polymer such as acrylic. Examples of these dichroic dye polymers include polymers listed in JP-A No. 2016-4055 and polymers obtained by polymerizing the compounds of [Chemical formula 6] to [Chemical formula 12] of JP-A No. 2014-206682.

The content of the dichroic dye in the polarizing film is preferably 0.1 to 30% by mass, more preferably 0.5 to 20% by mass, from the viewpoint of improving the orientation of the dichroic pigment. , more preferably 1.0 to 15% by weight, particularly preferably 2.0 to 10% by weight.

The polarizing film preferably further contains a polymerizable liquid crystal compound in order to improve film strength, degree of polarization, and film homogeneity. Note that the polymerizable liquid crystal compound herein also includes a film after polymerization.

(Polymerizable liquid crystal compound)
A polymerizable liquid crystal compound is a compound that has a polymerizable group and exhibits liquid crystallinity.
A polymerizable group means a group that participates in a polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group refers to a group that can undergo a polymerization reaction with active radicals, acids, etc. generated from a photopolymerization initiator, which will be described later. Examples of the polymerizable group include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, oxetanyl group, and the like. Among these, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferable, and acryloyloxy group is more preferable. The compound exhibiting liquid crystallinity may be a thermotropic liquid crystal or a lyotropic liquid crystal, or may be a nematic liquid crystal or a smectic liquid crystal in the thermotropic liquid crystal.

The polymerizable liquid crystal compound is preferably a smectic liquid crystal compound, and more preferably a higher-order smectic liquid crystal compound, since higher polarization properties can be obtained. When the liquid crystal phase formed by the polymerizable liquid crystal compound is a high-order smectic phase, a polarizing film with a higher degree of orientation order can be manufactured.

Specific preferred polymerizable liquid crystal compounds include, for example, JP-A No. 2002-308832, JP-A No. 2007-16207, JP-A No. 2015-163596, JP-A No. 2007-510946, and JP-A No. 2013-114131. Publication No. WO2005/045485, Lub et al. Recl. Trav. Chim. Examples include those described in Pays-Bas, 115, 321-328 (1996).

The content of the polymerizable liquid crystal compound in the polarizing film is preferably 70 to 99.5% by mass, more preferably 75 to 99% by mass, and more preferably 75 to 99% by mass in the polarizing film, from the viewpoint of increasing the orientation of the polymerizable liquid crystal compound. It is preferably 80 to 97% by weight, particularly preferably 83 to 95% by weight.

The polarizing film can be provided by applying a polarizing film composition paint. The polarizing film composition paint may contain a solvent, a polymerization initiator, a sensitizer, a polymerization inhibitor, a leveling agent, a polymerizable non-liquid crystal compound, a crosslinking agent, and the like.

As the solvent, those listed as the solvent for the alignment control layer coating solution are preferably used.

The polymerization initiator is not limited as long as it polymerizes the polymerizable liquid crystal compound, but a photopolymerization initiator that generates active radicals when exposed to light is preferred. Examples of the polymerization initiator include benzoin compounds, benzophenone compounds, alkylphenone compounds, acylphosphine oxide compounds, triazine compounds, iodonium salts, and sulfonium salts.

The sensitizer is preferably a photosensitizer, such as xanthone compounds, anthracene compounds, phenothiazine, rubrene, and the like.

Examples of polymerization inhibitors include hydroquinones, catechols, and thiophenols.

The polymerizable non-liquid crystal compound is preferably one that copolymerizes with the polymerizable liquid crystal compound, and for example, when the polymerizable liquid crystal compound has a (meth)acryloyloxy group, (meth)crates can be mentioned. (Meth)acrylates may be monofunctional or polyfunctional. By using polyfunctional (meth)acrylates, the strength of the polarizing film can be improved. When a polymerizable non-liquid crystal compound is used, it is preferably contained in the polarizing film in an amount of 1 to 15% by weight, more preferably 2 to 10% by weight, particularly preferably 3 to 7% by weight. If it exceeds 15% by mass, the degree of polarization may decrease.

Examples of the crosslinking agent include compounds that can react with functional groups of polymerizable liquid crystal compounds and polymerizable non-liquid crystal compounds, such as isocyanate compounds, melamine, epoxy resins, and oxazoline compounds.

A polarizing film is provided by directly applying the polarizing film composition paint onto the reflective surface of the endless belt or onto the alignment control layer, followed by drying, heating, and curing if necessary.

As a coating method, a known method such as a gravure coating method, a die coating method, a bar coating method, an applicator method, or a printing method such as a flexographic method is employed.

After coating, the endless belt is guided to a hot air dryer, an infrared dryer, etc., and dried at 30 to 170°C, more preferably 50 to 150°C, and still more preferably 70 to 130°C. The drying time is preferably 0.5 to 30 minutes, more preferably 1 to 20 minutes, and even more preferably 2 to 10 minutes.

Heating can be performed to more firmly align the dichroic dye and polymerizable liquid crystal compound in the polarizing film. The heating temperature is preferably within a temperature range at which the polymerizable liquid crystal compound forms a liquid crystal phase.

When the polarizing film composition coating contains a polymerizable liquid crystal compound, it is preferably cured. Curing methods include heating and light irradiation, with light irradiation being preferred. By curing, the dichroic dye can be fixed in an oriented state. Curing is preferably carried out in a state in which the polymerizable liquid crystal compound forms a liquid crystal phase, and may be cured by irradiating light at a temperature that exhibits the liquid crystal phase. Examples of light in the light irradiation include visible light, ultraviolet light, and laser light. Ultraviolet light is preferred because it is easy to handle.

The irradiation intensity varies depending on the type and amount of the polymerization initiator and resin (monomer), but is preferably 100 to 10,000 mJ/cm ² , more preferably 200 to 5,000 mJ/cm ² based on 365 nm.

In a polarizing film, by applying a polarizing film composition paint onto an orientation control layer, the dye is oriented along the orientation direction of the orientation layer, and as a result, it has a polarized light absorption axis in a predetermined direction. When the control layer is not provided and the endless belt is coated directly, the polarizing film can also be oriented by irradiating the polarizing film forming composition with polarized light and curing the composition. It is preferable that the dichroic dye is then strongly oriented along the alignment direction of the polymeric liquid crystal by heat treatment.

The thickness of the polarizing film is 0.1 to 5 μm, preferably 0.3 to 3 μm, and more preferably 0.5 to 2 μm.

(phase difference layer)
Typical examples of the retardation layer include a layer provided between a polarizer and a liquid crystal cell of a liquid crystal display device for optical compensation, and a λ/4 layer and a λ/2 layer of a circularly polarizing plate. As the liquid crystal compound, raw or negative A plates, positive or negative C plates, O plates, etc., rod-shaped liquid crystal compounds, discotic liquid crystal compounds, etc. can be used depending on the purpose.

When used as optical compensation for a liquid crystal display device, the degree of retardation is appropriately set depending on the type of liquid crystal cell and the properties of the liquid crystal compound used in the cell. For example, in the case of the TN system, an O plate using discotic liquid crystal is preferably used. In the case of the VA system or the IPS system, C plates and A plates using rod-like liquid crystal compounds or discotic liquid crystal compounds are preferably used. Further, in the case of a λ/4 retardation layer and a λ/2 retardation layer of a circularly polarizing plate, it is preferable to use a rod-shaped compound to form an A plate. These retardation layers may be used not only as a single layer but also as a combination of a plurality of layers.

The liquid crystal compound used in these retardation layers is preferably a polymerizable liquid crystal compound having a polymerizable group such as a double bond, since the alignment state can be fixed.

Examples of rod-like liquid crystal compounds include JP 2002-030042, JP 2004-204190, JP 2005-263789, JP 2007-119415, JP 2007-186430, and JP 2007-186430. Examples include rod-shaped liquid crystal compounds having a polymerizable group described in JP-A No. 11-513360.
As a specific compound,
CH ₂ =CHCOO-(CH ₂ ) _m -O-Ph1-COO-Ph2-OCO-Ph1-O-(CH ₂ ) _n -OCO-CH=CH ₂
CH ₂ =CHCOO-(CH ₂ ) _m -O-Ph1-COO-NPh-OCO-Ph1-O-(CH ₂ ) _n -OCO-CH=CH ₂
CH ₂ =CHCOO-(CH ₂ ) _m -O-Ph1-COO-Ph2-OCH ₃
CH ₂ =CHCOO-(CH ₂ ) _m -O-Ph1-COO-Ph1-Ph1-CH ₂ CH(CH ₃ )C ₂ H ₅
In the formula, m and n are integers from 2 to 6,
Ph1 and Ph2 are 1,4-phenyl groups (Ph2 may be a methyl group at the 2nd position),
NPh is a 2,6-naphthyl group.
These rod-shaped liquid crystal compounds are commercially available from BASF as LC242, and can be used.

A plurality of these rod-like liquid crystal compounds may be used in combination in any ratio.

In addition, discotic liquid crystal compounds include benzene derivatives, truxene derivatives, cyclohexane derivatives, azacrown series, phenylacetylene series macrocycles, etc., and various compounds are described in JP-A No. 2001-155866. is preferably used.
Among these, as the discotic compound, a compound having a triphenylene ring represented by the following general formula (1) is preferably used.

In the formula, R1 to R6 are each independently hydrogen, a halogen, an alkyl group, or a group represented by -OX (wherein, X is an alkyl group, an acyl group, an alkoxybenzyl group, an epoxy-modified alkoxybenzyl group) group, acryloyloxy-modified alkoxybenzyl group, acryloyloxy-modified alkyl group). R1 to R6 are preferably acryloyloxy-modified alkoxybenzyl groups (where m is 4 to 10) represented by the following general formula (2).

The retardation layer can be provided by applying a retardation layer composition paint. The retardation layer composition paint may contain a solvent, a polymerization initiator, a sensitizer, a polymerization inhibitor, a leveling agent, a polymerizable non-liquid crystal compound, a crosslinking agent, and the like. For these, those explained in the orientation control layer and polarizing film can be used.

A retardation layer is provided by applying the retardation layer composition paint onto the reflective surface or orientation control layer of the endless belt, followed by drying, heating, and curing.

As for these conditions, the conditions explained in the section regarding the alignment control layer and the polarizing film are preferably used.

A plurality of retardation layers may be provided, and in this case, a plurality of retardation layers may be provided on one endless belt and transferred to the object.

Alternatively, the polarizing layer and the retardation layer may be provided on the reflective surface of one endless belt, and this may be transferred to the object. Furthermore, a protective layer may be provided between the polarizer and the retardation layer, or a protective layer may be provided on the retardation layer or between the retardation layers. These protective layers may also be provided on an endless belt together with the retardation layer and the polarizing film and transferred to the object.

(Circularly polarized light reflective layer)
The circularly polarized light reflective layer is preferably a cholesteric liquid crystal layer. Examples of the liquid crystal compound used in the circularly polarized light reflective layer include the liquid crystal compounds used in the polarizing film and retardation layer described above.

In order to align the circularly polarized light reflective layer with cholesteric liquid crystal, the paint for the circularly polarized light reflective layer preferably contains a chiral agent. By containing a chiral agent, a helical structure of the cholesteric liquid crystal phase is induced, making it easier to obtain the cholesteric liquid crystal phase.
Examples of chiral agents include, for example, Liquid Crystal Device Handbook, Chapter 3, Section 4-3, Chiral Agents for TN (Twisted Nematic) and STN (Super-twisted nematic displays), p. 199, edited by the 142nd Committee of the Japan Society for the Promotion of Science, 1989. Examples include compounds described in , isosorbide, isomannide derivatives, etc., and are not particularly limited. It is preferable that the chiral agent has a polymerizable group. The chiral agent is preferably used in an amount of 1 to 10 parts by weight based on 100 parts by weight of the liquid crystal compound.

Examples of the circularly polarized light reflecting layer include those described in JP-A-1-133003, JP-A-3416302, JP-A-3363-565, JP-A-8-271731, WO2016/194497, JP-A-2018-10086, etc. can be used as a reference.

The cholesteric liquid crystal layer may be one layer, but since the cholesteric liquid crystal layer has wavelength selectivity in its reflection characteristics, multiple cholesteric liquid crystal layers are provided in order to achieve uniform reflection characteristics in a wide range of visible light. It is preferable. In this case, a plurality of cholesteric liquid crystal layers may be provided by repeatedly providing one cholesteric liquid crystal layer on the endless belt and transferring it to the object. Alternatively, a plurality of cholesteric liquid crystal layers may be provided on one endless belt and transferred to the object.

Further, the circularly polarized light reflecting layer is sometimes used in combination with a λ/4 retardation layer and a polarizing layer as a laminate for improving brightness. In this case, for example, a λ/4 retardation layer and a circularly polarized light reflecting layer may be provided on separate endless belts and transferred to the object (polarizing plate) in order, or A four-phase retardation layer and a circularly polarized light reflecting layer may be provided and transferred to the object. Alternatively, the protective layer and the circularly polarized light reflecting layer may be provided on an endless belt and transferred to the object.

Examples of the protective layer include a transparent resin coating layer. Transparent resins include polyvinyl alcohol, ethylene vinyl alcohol copolymer, polyester, polyurethane, polyamide, polystyrene, acrylic resin, epoxy resin, and the like, but are not particularly limited. A crosslinked structure may be obtained by adding a crosslinking agent to these resins. Alternatively, a hard coat made of a photocurable composition such as acrylic may be used. Alternatively, after the protective layer is provided on the endless belt, the protective layer may be subjected to a rubbing treatment, and a liquid crystal compound layer may be provided thereon without providing an alignment control layer.

(Liquid crystal compound layer laminate)
In the present invention, a liquid crystal compound layer is provided on the reflective surface of an endless belt, and the liquid crystal compound layer provided on the endless belt is bonded and transferred to a transfer target to create a liquid crystal compound layer laminate.
The liquid crystal compound layer laminate includes a retardation film in which a film is provided with a retardation layer (liquid crystal compound layer), a polarizing plate in which a polarizing film (liquid crystal compound layer) is provided in a film, and a polarizing plate in which a retardation layer (liquid crystal compound layer) is provided in a polarizing plate. A retardation layer laminated polarizing plate (e.g. a polarizing plate with an optical compensation layer, a circularly polarizing plate) with a retardation layer (a liquid crystal compound layer), a polarizing plate with a polarization direction conversion layer with a λ/2 retardation layer (liquid crystal compound layer) Polarizing plates, circularly polarized light reflecting plates in which a circularly polarized light reflecting layer (liquid crystal compound layer) is provided on a film, brightness enhancement films in which a circularly polarized light reflecting layer (liquid crystal compound layer) is provided in a λ/4 retardation film, etc. It will be done.

The film of the transfer target is preferably a transparent resin film or a glass film. Examples of the transparent resin film include cellulose-based, acrylic-based, cyclic polyolefin-based, and polyester-based films, and the transparent resin film may be a film without a retardation or a film with a retardation.

The polarizing film (polarizing plate) of the transfer target may have a protective film on both sides of the polarizer, only one side may have a protective film, or it may have no protective film. good. A protective coat layer may be provided instead of the protective film. Moreover, when the film to be transferred is a polarizer, the polarizer may be a polarizer provided on a base material that is later peeled off. Among these, it is preferable that a retardation layer is provided on the polarizer surface of a polarizing film having a protective film on only one side by the method of the present invention.

When the retardation layer laminate obtained by the present invention is a retardation layer laminated polarizing plate, the retardation layer laminated polarizing plate may be used as a polarizing plate with an optical compensation layer of a liquid crystal display device or a circularly polarizing plate. Preferably. The circularly polarizing plate is preferably a circularly polarizing plate for antireflection in organic EL display devices, micro LED display devices, and the like.

In the case of a polarizing plate with an optical compensation layer or a circularly polarizing plate, a plurality of retardation layers are often provided. For example, in the case of a polarizing plate with an optical compensation layer, there are combinations of C plate and A plate, combinations of A plates, etc. In the case of a circularly polarizing plate, the A plate has a λ/4 retardation layer and a λ/2 retardation layer. Examples include combinations of layers.

In the case of a polarizing plate with a polarization direction conversion layer, the polarizing plate is preferably a reflective polarizing plate or an absorption type polarizing plate. The transmission axis of commercially available reflective polarizing plates is in the direction of film production, and the transmission axis of general absorption polarizers made of stretched PVA film is in the width direction of film production, so they cannot be rolled to one another. Pasting with rolls is not possible. A λ/2 retardation layer is provided on either the reflective polarizing plate or the absorption type polarizing plate, and the slow axis of the λ/2 retardation layer is at an angle of 45 degrees with the transmission axis between the reflective polarizing plate or the absorption type polarizing plate. By doing so, roll-to-roll lamination becomes possible.
A polarizing plate with a polarization direction conversion layer is used on the light source side of a liquid crystal display device, and can improve the brightness of the liquid crystal display device.

A brightness-enhancing film is used on the light source side of a liquid crystal display device, and can improve the brightness of the liquid crystal display device. In addition, it can be used in combination with an antireflection circularly polarizing plate for organic EL display devices, etc., as a brightness-enhancing film for organic EL displays, etc., or as an antireflection circularly polarizing plate with suppressed reduction in brightness.

A detailed explanation will be given below using a circularly polarizing plate as an example. In the case of a circularly polarizing plate, a λ/4 retardation layer is used as the retardation layer. The front retardation of the λ/4 retardation layer is preferably 100 to 180 nm. More preferably, it is 120 to 150 nm. When only a λ/4 retardation layer is used as a circularly polarizing plate, the orientation axis (slow axis) of the λ/4 retardation layer and the transmission axis of the polarizer are preferably 35 to 55 degrees, more preferably 40 to 50 degrees. degree, more preferably 42 to 48 degrees. When used in combination with a polyvinyl alcohol stretched film polarizer, the absorption axis of the polarizer is generally in the length direction of the long polarizer film, so a λ/4 retardation film is placed on the endless belt. When a layer is provided, it is preferable to orient the liquid crystal compound within the above range with respect to the circumferential direction (running direction) of the endless belt. Note that when the angle of the transmission axis of the polarizer is different from the above, the liquid crystal compound is oriented so that the above relationship is achieved by taking into consideration the angle of the transmission axis of the polarizer.

A circularly polarizing plate is created by transferring the λ/4 retardation layer on the endless belt to a polarizing plate as an object. Specifically, after bonding the polarizing plate and the λ/4 retardation layer surface on the endless belt, the laminate of the polarizing plate and the λ/4 retardation layer is peeled off from the endless belt to create a circularly polarizing plate. The polarizing plate to be used may have a protective film on both sides of the polarizer, but it is preferable to have a protective film on only one side. If the polarizing plate is provided with a protective film on only one side, it is preferable to bond the retardation layer to the opposite side of the protective film (polarizer side). If protective films are provided on both sides, it is preferable to attach the retardation layer to the side intended for the image cell side. The surface intended for the image cell side is a surface that is generally provided on the viewing side, such as a low reflection layer, antireflection layer, antiglare layer, etc., and is not subjected to surface processing. The protective film on the side to which the retardation layer is bonded is preferably a TAC, acrylic, COP, or other protective film without retardation. Moreover, a polarizing plate may be provided with a protective coat layer such as a curable resin instead of a protective film.

Polarizers include polarizers created by stretching a PVA-based film alone, and polarizers created by coating an unstretched base material such as polyester or polypropylene with PVA and stretching the entire base material. Examples include those transferred to a film, and those obtained by coating or transferring a polarizer made of a liquid crystal compound and a dichroic dye onto a polarizer protective film, and any of them are preferably used.

As a pasting method, conventionally known adhesives, adhesives, etc. can be used. As the adhesive, polyvinyl alcohol adhesives, ultraviolet curable adhesives such as acrylic and epoxy, and thermosetting adhesives such as epoxy and isocyanate (urethane) are preferably used. Examples of the adhesive include acrylic, urethane, and rubber adhesives. Further, it is also preferable to use an optical transparent adhesive sheet that does not have an acrylic base material.

As the polarizer protective film on the opposite side of the polarizer to the side on which the retardation layer is provided, commonly known materials such as TAC, acrylic, COP, polycarbonate, and polyester can be used. Among them, TAC, acrylic, COP, and polyester are preferred. The polyester is preferably polyethylene terephthalate. In the case of polyester, it is preferably a zero retardation film with in-plane retardation of 100 nm or less, particularly 50 nm or less, or a high retardation film of 3000 nm to 30000 nm.

When using a high retardation polyester film as a polarizer protective film on the opposite side of the polarizer to the side on which the retardation layer is provided, polarized The angle between the transmission axis of the child and the slow axis of the polyester film is preferably in the range of 30 to 60 degrees, more preferably in the range of 35 to 55 degrees. In order to reduce iridescence when observed from a shallow oblique direction with the naked eye, the angle between the transmission axis of the polarizer and the slow axis of the polyester film should be 10 degrees or less, or even 7 degrees or less. Alternatively, the temperature is preferably 80 to 100 degrees, more preferably 83 to 97 degrees.

The polarizer protective film on the opposite side of the polarizer to the side on which the retardation layer is provided may be provided with an antiglare layer, an antireflection layer, a low reflection layer, a hard coat layer, etc.

(Composite retardation layer)
If the λ/4 retardation layer is used alone, coloring may occur over a wide range of visible light region without achieving λ/4. Therefore, a λ/4 retardation layer is sometimes used in combination with a λ/2 retardation layer. The front retardation of the λ/2 retardation layer is preferably 200 to 360 nm. More preferably, the wavelength is 240 to 300 nm.

In this case, it is preferable that the λ/4 retardation layer and the λ/2 retardation layer are arranged at an angle such that the total angle is λ/4. Specifically, the angle (θ) between the orientation axis (slow axis) of the λ/2 retardation layer and the transmission axis of the polarizer is preferably 5 to 20 degrees, more preferably 7 to 17 degrees. The angle between the orientation axis (slow axis) of the λ/2 retardation layer and the orientation axis (slow axis) of λ/4 is preferably in the range of 2θ + 45 degrees ± 10 degrees, more preferably in the range of 2θ + 45 degrees ± 5 degrees. The range is more preferably 2θ+45 degrees ±3 degrees.

In this case as well, when used in combination with a polyvinyl alcohol stretched film polarizer, the absorption axis of the polarizer is generally in the longitudinal direction of the elongated polarizer. When a two-phase retardation layer or a λ/4 retardation layer is provided, the liquid crystal compound is preferably oriented within the above range in the circumferential direction of the endless belt or in the direction perpendicular to the circumference. Note that when the angle of the transmission axis of the polarizer is different from the above, the liquid crystal compound is oriented so that the above relationship is achieved by taking into consideration the angle of the transmission axis of the polarizer.

As examples of these methods and retardation layers, JP2008-149577A, JP2002-303722A, WO2006/100830A, JP2015-64418A, etc. can be referred to. .

Furthermore, it is also a preferable form to provide a C plate layer on the λ/4 retardation layer in order to reduce changes in coloring when viewed from an angle. As the C-plate layer, a positive or negative C-plate layer is used depending on the characteristics of the λ/4 retardation layer or the λ/2 retardation layer.

For example, if a combination of a λ/4 retardation layer and a λ/2 retardation layer is used,
・A λ/4 retardation layer and a λ/2 retardation layer are provided in this order on an endless belt, and this is transferred onto a polarizer. ・A λ/2 retardation layer is provided on an endless belt, and this is transferred onto a polarizer. A method is adopted in which a λ/4 retardation layer is separately provided on an endless belt, and this is transferred onto the λ/2 retardation layer surface of a laminate of a polarizer and a λ/2 retardation layer. be able to.

Also, when laminating C plates, there are two methods: transferring a C plate layer provided on an endless belt onto a λ/4 retardation layer provided on a polarizer, and a method of transferring a C plate layer provided on an endless belt. Various methods can be employed, such as providing a λ/4 retardation layer or a λ/2 retardation layer and a λ/4 retardation layer thereon, and then transferring the layers.

The thickness of the circularly polarizing plate thus obtained is preferably 120 μm or less. The thickness is more preferably 100 μm or less, further preferably 90 μm or less, particularly preferably 80 μm or less, and most preferably 70 μm or less.

In transferring the retardation layer, the retardation layer and the target film can be bonded together using an adhesive, a pressure-sensitive adhesive, or the like. Examples of the adhesive include thermosetting adhesives such as isocyanate-based and epoxy-based adhesives, and ultraviolet-curing adhesives such as acrylic-based adhesives, with ultraviolet-curing adhesives being particularly preferred. Moreover, it is preferable to use an optical adhesive sheet without a base material as the adhesive.

(Equipment used in the present invention)
Examples of equipment used in the method of the present invention will be briefly explained based on the drawings.
FIG. 1 is a schematic diagram of an example of an apparatus used in the method of the invention.
An endless belt (1) is provided between two endless belt drive rolls (2) and is moving in the direction of the arrow. Additionally, the endless belt is prevented from sagging by support rolls (not shown).

The orientation control layer composition paint is applied onto the endless belt by the coater head (3), and after drying in the drying oven (5), it is irradiated with polarized ultraviolet rays in a predetermined direction, giving the orientation control layer an orientation control force. It will be done. For polarized ultraviolet light, the light from the ultraviolet lamp (7) for the alignment control layer is polarized using a polarizing filter (8), and the polarizing filter (8) is rotatable so that the direction of polarization can be changed.
Subsequently, a retardation layer composition paint containing a liquid crystal compound is applied onto the alignment control layer of the endless belt by a coater head (4) and dried in a drying oven (6). Further, while the liquid crystal compound is oriented in the heat treatment oven (10), ultraviolet light is irradiated from the ultraviolet lamp (9) for curing the retardation layer, and the liquid crystal compound is fixed in the oriented state, so that it is fixed on the endless belt. A retardation layer is provided.

On the other hand, a polarizing plate is unwound from a roll of polarizing plate (31) having a protective film on one side, and an ultraviolet curing adhesive is applied to the polarizer surface by a coater head (40). By (33), the retardation layer on the endless belt and the polarizing plate are superimposed, and they are irradiated with ultraviolet light from the ultraviolet lamp (42) and bonded together.

The laminate of the polarizing plate-retardation layer-orientation control layer is peeled off from the endless belt (1) via the guide roll 34 and wound up as a circularly polarizing plate roll (32).

FIG. 2(a) is an example of an apparatus used in the present invention that applies an alignment control force to an alignment control layer by rubbing. Here, after drying, the surface of the orientation control layer is subjected to a rubbing treatment using a rubbing roll (12).
FIG. 2B is a view of the rubbing section of FIG. 2A viewed diagonally from above. The rubbing roll (12) is movable in the direction of the arcuate arrow, so that the rubbing direction can be adjusted.

FIG. 3 is a schematic diagram of another example of apparatus used in the method of the invention. In FIG. 1, the orientation control layer and the retardation layer are provided only on the top of the endless belt, but in FIG. 3, the orientation control layer is provided on the top and the retardation layer is provided on the bottom.

FIG. 4 is a schematic diagram of another example of apparatus used in the method of the invention. The endless belt has a triangular shape with three driving rolls.

FIG. 5 is a schematic diagram of another example of apparatus used in the method of the invention. By providing the first retardation layer on the upper side and the second retardation layer on the lower side, it is possible to provide and transfer two retardation layers on the endless belt.

FIG. 6 is a schematic diagram of an example of an apparatus for transferring using a substrate-less optical adhesive sheet. The optical adhesive sheet is unwound from the roll (51) of the optical adhesive sheet, passes through the guide roll (37), and the easy release film is peeled off.
On the other hand, a polarizing plate having a protective film on only one side is unwound from the polarizing plate roll (35), and the polarizer surface of the polarizing plate and the adhesive surface of the optical adhesive sheet are bonded together at the press roll (38). Furthermore, after passing through a press roll, the heavy release film is peeled off, and an adhesive layer is provided on the polarizer surface of the polarizing plate.
Further, the polarizing plate having an adhesive layer is bonded to the retardation layer on the endless belt at the press roll (39) portion, and then the retardation layer is peeled off from the endless belt and transferred to the polarizing plate, and then the circularly polarizing plate is rolled. It is wound up as a shaped article (36).

(Inspection method for retardation layer on endless belt)
The optical properties of the retardation layer on the endless belt can be inspected while it is stacked on the endless belt. Light for inspection is irradiated from the retardation layer side. The light that has passed through the retardation layer is reflected by the specular reflective surface of the endless belt, and the reflected light passes through the retardation layer again. By inspecting the polarization state of this reflected light, the orientation state of the retardation layer can be determined.

Further details will be explained using a λ/4 retardation layer used in a circularly polarizing plate as an example.

It is preferable to provide a polarizing filter between the light source used for inspection and the retardation layer. Normally, the λ/4 layer used for circularly polarized light etc. is oriented obliquely to the circumferential direction of the endless belt, so it is preferable to irradiate linearly polarized light parallel or perpendicular to the circumferential direction of the endless belt. . Parallel to the circumferential direction of the endless belt is preferably -10 to +10 degrees, more preferably -7 to 7 degrees, even more preferably -5 to 5 degrees, particularly preferably -3 to 3 degrees, and most preferably - 2 to 2 degrees. Perpendicular to the circumferential direction of the endless belt is preferably 80 to 100 degrees, more preferably 83 to 97 degrees, even more preferably 85 to 95 degrees, particularly preferably 87 to 93 degrees, and most preferably 88 to 92 degrees. be. Since a polarizer made of stretched polyvinyl alcohol that is commonly used has a transmission axis perpendicular to the flow direction, if the above range is exceeded, the difference from the actual state becomes large and accurate evaluation may not be possible.

It is also preferable to provide a polarizing filter between the light receiver and the retardation layer. For example, if the liquid crystal compound layer is a λ/4 layer or a combination of a λ/4 layer and a λ/2 layer, which converts linearly polarized light into circularly polarized light, the orientation state of the liquid crystal compound layer may be as designed. In this case, the reflected light is linearly polarized light. By installing a polarizing filter at an angle that does not transmit light in the vibration direction of this linearly polarized light, if the retardation layer is as set, the light detected by the receiver will be in an extinction state, but the light detected by the receiver will be in an extinction state. If there is any leakage, it can be seen that the retardation layer has deviated from the design.

The polarizing filter between the light source used for inspection and the retardation layer and the polarizing filter between the light receiver and the retardation layer may be the same. For example, a large polarizing filter that covers the width of the liquid crystal compound layer to be inspected may be used, and a light source and a light receiver may be installed on the opposite side of the polarizing filter from the liquid crystal compound layer to be inspected.

When the retardation layer is an optical compensation layer used in a liquid crystal display, the polarization state changed by the retardation layer is disposed between the retardation layer and the polarizing filter on the light emitting side or the polarizing filter on the light receiving side, or between both. It is preferable to provide a retardation plate for converting reflected light into linearly polarized light when the reflected light reaches a designed state.
In this case, as well as above, if the retardation layer is as set, the light detected by the receiver is in the extinction state, but if there is light leakage, the retardation layer is deviated from the design. I understand that.

In addition, multiple types of light receivers with slightly different angles of polarizing filters and angles and phase differences of retardation plates are installed, and it is possible to detect in which direction and by how much the retardation layer's phase difference and orientation direction are shifted. You can also do it.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples, and may be implemented with appropriate changes within the scope of the spirit of the present invention. Both are possible and are within the technical scope of the present invention.
The evaluation method of physical properties in Examples is as follows.

(1) Surface roughness Ra, Rzjis, Rz
It was determined from a roughness curve measured using a contact roughness meter (manufactured by Mitutoyo Corporation, SJ-410, detector: 178-396-2, stylus: standard stylus 122AC731 (2 μm)). The settings were made as follows.
Curve: R
Filter: GAUSS
λc: 0.8mm
λs: 2.5μm
Measurement length: 5mm
Measurement speed: 0.5mm/s
Note that the values were determined in accordance with JIS B0601-2001.

(2) Specular gloss Based on the specular gloss measurement method of JIS Z8741 (1997), when the incident angle is 60° on a glass surface with a refractive index of 1.567, reflectance of 10% is measured as gloss of 100 (%). This is the value. The glossiness measurement conditions are as follows.
Measurement conditions: Gs (60°)
Measuring device: Digital gloss meter “(GM-3D)” manufactured by Murakami Color Research Institute Co., Ltd.

(Photoalignment control layer composition paint)
Based on the descriptions of Example 1, Example 2, and Example 3 of JP-A No. 2013-33248, a 5% by mass cyclopentanone solution of the polymer of the following formula was produced.

(Rubbing orientation control layer composition paint)
・10 parts by mass of the following modified polyvinyl alcohol
・Water 371 parts by mass ・Methanol 119 parts by mass ・Glutaraldehyde 0.5 parts by mass

(Composition paint A for retardation layer)
LC242 (manufactured by BASF) 95 parts by mass Trimethylolpropane triacrylate 5 parts by mass Irgacure 379 3 parts by mass Surfactant 0.1 parts by mass Methyl ethyl ketone 250 parts by mass

(Composition paint B for retardation layer)
Liquid crystal discotic compound 18 parts by mass Ethylene glycol-modified trimethylolpropane triacrylate (V#360, manufactured by Osaka Organic Chemical Industry Co., Ltd.) 2.0 parts by mass Cellulose acetate butyrate (CAB531-1, manufactured by Eastman Chemical Co., Ltd.) 0.4 parts by mass Photopolymerization initiator (Irgacure-907, manufactured by Ciba Geigy) 0.6 parts by mass Photosensitizer (Kayacure-DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.2 parts by mass Methyl ethyl ketone 34.3 parts by mass Department
The liquid crystal discotic compound is a discotic liquid crystal compound represented by the following formula.

(PVA polarizer transfer laminate)
Polyethylene terephthalate having an intrinsic viscosity of 0.62 dl/d was melted and kneaded in an extruder as a thermoplastic resin base material, and then extruded into a sheet onto a cooling roll to form an unstretched film with a thickness of 100 μm. An aqueous solution of polyvinyl alcohol having a degree of polymerization of 2400 and a degree of saponification of 99.9 mol % was applied onto one side of this unstretched film and dried to form a PVA layer.
The obtained laminate was stretched and wound up twice in the longitudinal direction between rolls having different circumferential speeds at 120°C. Next, the obtained laminate was treated with a 4% boric acid aqueous solution for 30 seconds, and then immersed in a mixed aqueous solution of iodine (0.2%) and potassium iodide (1%) for 60 seconds for dyeing. Then, it was treated with a mixed aqueous solution of potassium iodide (3%) and boric acid (3%) for 30 seconds.
Furthermore, this laminate was uniaxially stretched in the longitudinal direction in a mixed aqueous solution of boric acid (4%) and potassium iodide (5%) at 72°C, then washed with a 4% aqueous potassium iodide solution, and the aqueous solution was stretched with an air knife. After removing it, it was dried in an oven at 80° C., and both ends were slit and wound up to obtain a PVA polarizer transfer laminate having a width of 50 cm and a length of 1000 m. The total stretching ratio was 6.5 times, and the thickness of the polarizer was 5 μm. The thickness was determined by embedding the base laminated polarizer in epoxy resin, cutting out a section, and observing it with an optical microscope.

(Creation of polarizing plate A)
A polyethylene terephthalate film (manufactured by Toyobo Co., Ltd., Cosmoshine (TM) SRF) with a thickness of 80 μm was slit to a width of 50 cm and a length of 1000 m, and after applying an ultraviolet curable adhesive to the PVA easily adhesive surface, it was laminated for PVA polarizer transfer. It was attached to the polarizer surface of the body and wound up into a roll.

Example 1
Using the equipment shown in Figure 1, the photo-alignment control layer composition paint is supplied from the coater head (3) onto the reflective surface of the endless belt and applied, and then led to the drying oven (5) and dried at 80°C. , polarized ultraviolet rays were irradiated to provide a photo-alignment control layer. The polarization direction (vibration direction of the electric field) was set at 45 degrees with respect to the circumferential direction (running direction) of the endless belt by adjusting the angle of the polarizing filter (8).
Subsequently, the retardation layer composition paint A is supplied from the coater head (4) onto the photo-alignment control layer, applied, guided to a drying oven (6), heated to 110°C to evaporate the solvent, and rod-shaped liquid crystal. compound (LC242) was oriented. Further, the retardation layer was fixed by irradiating ultraviolet rays in a heat treatment oven (10) equipped with an ultraviolet lamp (9) at 110°C.

Unwind polarizing plate A from the roll of polarizing plate A, peel off the polyethylene terephthalate base material used to create the PVA polarizer transfer laminate (not shown in Figure 1), and apply ultraviolet curable adhesive to the polarizer surface. After coating using the coater head (40), irradiating ultraviolet rays using an ultraviolet lamp (42) while superimposed on the retardation layer on the endless belt and bonding, the circularly polarizing plate (polyethylene terephthalate film (Toyobo Co., Ltd.) Cosmoshine (TM) SRF)-polarizer-retardation layer laminate) manufactured by Co., Ltd., was peeled off from the endless belt and wound into a roll.

The endless belt was made of SUS316 with a width of 50 cm and a circumference of 15 m, and electroless nickel plating was applied to the mirror-polished surface.
The properties of a specular reflective surface are as follows.

In addition, as shown in FIG. 7, the retardation layer provided on the endless belt is irradiated with visible light (light source 61) through polarizing plates (63, 64), and the reflected light is captured by a CCD camera (62). When photographed, it was confirmed that reflection was effectively suppressed and the phase difference (140 nm) was as designed. At this time, the absorption axes of the polarizing plates (63, 64) were both parallel to the circumferential direction of the endless belt.

Example 2
Example 1 except that the coating thickness of composition paint A for retardation layer was changed and that the polarization direction of the polarized ultraviolet rays was set at 75 degrees with respect to the circumferential direction of the endless belt and a photo-alignment control layer was provided. In the same manner as above, a λ/2 retardation layer is provided on the endless belt, and this is transferred onto the polarizer surface of the polarizing plate A to obtain a laminate of the polarizing plate A and the λ/2 retardation layer. I wound it up.

Subsequently, a λ/4 retardation layer was provided on the endless belt in the same manner as in Example 1 except that the polarization direction of the polarized ultraviolet rays was set at 15 degrees with respect to the circumferential direction of the endless belt and a photo-alignment control layer was provided. This was transferred onto the λ/2 retardation layer of the above-mentioned laminate of the polarizing plate A and the λ/2 retardation layer, and the layer was bonded to the polarizing plate A (polyethylene terephthalate film - polarizer) - λ/2 retardation layer. A laminate (circularly polarizing plate) of layer-λ/4 retardation layers was obtained and wound into a roll.

Also, the absorption axis direction of the polarizing plate (63) is set at 30 degrees with the circumferential direction of the endless belt, and the absorption axis direction of the polarizing plate (64) is set at 90 degrees with the absorption axis direction of the polarizing plate (63). When the λ/2 retardation layer provided on the endless belt was observed in the same manner as in Example 1 except that the λ/2 retardation layer was 280 nm).

Furthermore, the absorption axis direction of the polarizing plates (63, 64) was set at 60 degrees with respect to the circumferential direction of the endless belt, and the λ/4 retardation layer provided on the endless belt was observed in the same manner as in Example 1. However, it was confirmed that reflection was suppressed and the phase difference (140 nm) was as designed.

Example 3
The polarized ultraviolet irradiation device (7) and light shielding plate (11) of the apparatus shown in FIG. 1 were removed, and as shown in FIG. 2, an apparatus equipped with a rubbing roll (12) was used.
The rubbing orientation control layer composition paint is supplied from the coater head (3) onto the reflective surface of the endless belt, applied, guided to a drying oven (5) and dried at 80°C, and then rubbed with a rubbing roll (12) for orientation control. The surface of the layer was rubbed. The angle and rotation speed of the rubbing roll were adjusted so that the rubbing direction was 45 degrees with respect to the circumferential direction (running direction) of the endless belt. As described above, a roll of circularly polarizing plate was obtained in the same manner as in Example 1 except that a rubbed alignment control layer was provided on the endless belt instead of the optical alignment control layer.

(Evaluation of anti-reflection effect of circularly polarizing plate)
Peel off the circularly polarizing plate of a commercially available organic EL television, cut out the circularly polarizing plate obtained in Examples 1, 2, and 3 to a width of 40 cm and a length of 60 cm, and prepare an organic EL display device with the retardation layer facing the cell side. was attached using an optical adhesive sheet. The antireflection effect was evaluated in comparison with a portion to which no circularly polarizing plate was attached. The results are shown in Table 2.
◎: Reflection was effectively suppressed.
○: Slightly colored reflected light was observed, but it was at a level that caused no problem in use.
×: There was almost no effect of suppressing reflection.

In addition, the thickness of the retardation layer was several μm, which made it possible to make it thinner than a conventional circularly polarizing plate using a retardation film (the thickness of the retardation layer was several tens of μm).

Example 4
A photo-alignment control layer was provided in the same manner as in Example 1, and retardation layer composition paint B was applied thereon. The temperature during drying and ultraviolet irradiation was set to 120° C., and a 2 μm thick retardation layer in which disk portions of discotic liquid crystal compounds were oriented obliquely was provided on the endless belt. In the same manner as in Example 1, it was transferred onto the polarizer surface of polarizing plate A to obtain a roll-shaped polarizing plate on which an optical compensation layer was laminated.

(Evaluation of polarizing plate with laminated optical compensation layer)
A liquid crystal panel was taken out from a commercially available TN type liquid crystal display device (personal computer display), and the viewing side polarizing plate and the light source side polarizing plate of the liquid crystal panel were peeled off to prepare a liquid crystal display cell. On the other hand, a polarizing plate cut into the size of a display was prepared from the polarizing plate roll on which the optical compensation layer obtained in Example 4 was laminated. Using an optical adhesive sheet, a polarizing plate was attached to the viewing side and light source side of the liquid crystal display cell with the retardation layer facing the cell side to form a liquid crystal panel, which was then incorporated into the original liquid crystal display device. The absorption axis direction of the polarizing plate was made to be the same as the absorption axis direction of the original polarizing plate.
When images were displayed and observed, image reproducibility almost equivalent to that of the original liquid crystal display device was observed even when viewed from an oblique direction. Note that, compared to the thickness of the polarizing plate on which the original retardation film was laminated, which was approximately 150 μm (measured with a digital thickness meter), the thickness of the polarizing plate of Example 4 was approximately 85 μm, which made it thinner.

1 Endless belt 2 Endless belt drive roll 3, 13, 23 Coater head for orientation control layer 4, 14, 24 Coater head for retardation layer 5, 15, 25 Drying oven for orientation control layer 6, 16, 26 For retardation layer Drying oven 7, 9, 17, 19, 27, 29 Ultraviolet lamp 8, 18, 28 Polarizing filter 10, 20, 30 Heat treatment oven 11 Light shielding plate 12 Rubbing rolls 31, 35 Rolled polarizing plate (unrolled)
32, 36 Rolled retardation layer laminated polarizing plate (rolled)
33, 38, 39 Press rolls 34, 37 Guide roll 40 Coater head for adhesive 41 Backup roll 42 Ultraviolet lamp for curing adhesive 51 Rolled optical adhesive sheet (unrolled)
52 Lightly peelable film of optical adhesive sheet (winding)
53 Heavy release film of optical adhesive sheet (winding)
61 Visible light lamp 62 Detector 63, 64 Polarizing filter

Claims (2)

A method for producing a liquid crystal compound layer laminate, comprising at least the following steps (a) and (b),
(a) Step of providing a liquid crystal compound layer with a fixed orientation on the specular reflective surface of an endless belt having a specular reflective surface (b) Transferring the liquid crystal compound layer provided on the specular reflective surface to the transfer target A step of obtaining a liquid crystal compound layer laminate in which a liquid crystal compound is laminated on a transfer target by transferring; the transfer target is any one of a transparent resin film, a glass film, and a polarizing film;
The liquid crystal compound layer is at least one of a λ/4 retardation layer, a λ/2 retardation layer, a polarizing film, and a circularly polarized light reflecting layer,
A liquid crystal compound, wherein the liquid crystal compound layer laminate is any one of a retardation film, a polarizing plate, a retardation layer laminated polarizing plate, a circularly polarizing plate, a polarizing plate with a polarization direction conversion layer, a circularly polarized light reflecting plate, and a brightness enhancement film. Method for manufacturing layer laminate. The method for producing a liquid crystal compound layer laminate according to claim 1, wherein the endless belt is a metal belt.