KR20230172504A - Laminate and its manufacturing method - Google Patents

Abstract

The present invention provides a laminate with good adhesion between the linear polarizer and the retardation layer using a water-based adhesive even when both the linear polarizer and the retardation layer constituting the laminate have a light transmittance of 10% or less at a wavelength of 380 nm, and a method for manufacturing the same. The purpose is to provide. In the present invention, a linear polarizer, a water-based adhesive layer, and a retardation layer are bonded in this order, the retardation layer includes a layer containing a cured product of a polymerizable liquid crystal compound, and both the linear polarizer and the retardation layer have a wavelength of 380 nm. A laminate having a light transmittance of 10% or less is provided.

Description

Laminate and its manufacturing method

The present invention relates to a laminate, and further relates to a method of manufacturing the laminate.

Patent Document 1 proposes a polarizing plate with a retardation layer including a polarizer and a retardation layer.

Patent Document 1: Japanese Patent Publication No. 2018-017996

In a laminate including a linear polarizer and a retardation layer, the linear polarizer and the retardation layer are often bonded using an active energy ray-curable adhesive. When both the linear polarizer and the retardation layer had low light transmittance, there were cases where sufficient adhesion between the layers was not obtained.

As an active energy ray-curable adhesive, a type of adhesive in which the curing reaction proceeds with light in the ultraviolet wavelength range is often used. When both the linear polarizer and the retardation layer to be joined have low light transmittances in the ultraviolet wavelength range, there are cases where sufficient adhesion between the layers cannot be obtained.

In addition, when using an adhesive that cures with light in the visible light wavelength range, where the light transmittance of the linear polarizer and retardation layer is high, response from the production facility is necessary to prevent the adhesive from curing unintentionally, making application difficult. It was difficult.

The present invention aims to provide a laminate with good adhesion between the linear polarizer and the retardation layer, and a method for manufacturing the same, even when both the linear polarizer and the retardation layer constituting the laminate have a light transmittance of 10% or less at a wavelength of 380 nm. Do it as

The present invention provides the following laminate and a method for manufacturing the laminate.

[1] A linear polarizer, a water-based adhesive layer, and a retardation layer are bonded in this order,

The retardation layer includes a layer containing a cured product of a polymerizable liquid crystal compound,

A laminate wherein both the linear polarizer and the retardation layer have a light transmittance of 10% or less at a wavelength of 380 nm.

[2] The laminate according to [1], wherein the water-based adhesive layer and a layer containing a cured product of the polymerizable liquid crystal compound are in contact and bonded.

[3] The linear polarizer has a protective film on one or both sides of the polarizer,

The laminate according to [1] or [2], wherein the protective film has a moisture permeability of 200 g/m2·24 hr or less.

[4] The laminate according to any one of [1] to [3], wherein the retardation layer includes a 1/4 wavelength retardation layer.

[5] The laminate according to any one of [1] to [4], wherein the retardation layer includes a 1/2 wavelength retardation layer.

[6] The laminate according to any one of [1] to [5], comprising only one layer containing a cured product of a polymerizable liquid crystal compound.

[7] A method of manufacturing a laminate in which a linear polarizer, a water-based adhesive layer, and a retardation layer are bonded in this order,

A first step of forming a coating film of a water-based adhesive on the linear polarizer,

A second step of drying the water-based adhesive film to form a water-based adhesive layer;

After performing surface activation treatment on the surface of the water-based adhesive layer opposite to the linear polarizer side and the surface of the retardation layer on the water-based adhesive layer side, the linear polarizer and the retardation layer are bonded through the water-based adhesive layer. 3 process

Provided in this order,

A method for producing a laminate, wherein both the linear polarizer and the retardation layer have a light transmittance of 10% or less at a wavelength of 380 nm.

[8] The method for producing a laminate according to [7], further comprising a step of heating the laminate after the third step.

[9] The second process is,

A step of laminating a release film on the water-based adhesive coating film;

A process of peeling off the release film after drying the coating film of the water-based adhesive.

The method for producing a laminate according to [7] or [8], further comprising:

According to the present invention, even when both the linear polarizer and the retardation layer constituting the laminate have a light transmittance of 10% or less at a wavelength of 380 nm, a laminate having good adhesion between the linear polarizer and the retardation layer and a method for manufacturing the same are provided. The purpose is to

1 is a schematic cross-sectional view showing an example of the layer structure of the laminate of the present invention.
Figure 2 is a schematic cross-sectional view showing an example of a method for manufacturing a laminate of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments. In all drawings below, the scale of each component is appropriately adjusted to make it easier to understand, and the scale of each component shown in the drawings does not necessarily match the scale of the actual component.

In the laminate of the present invention, a linear polarizer, a water-based adhesive layer, and a retardation layer are bonded in this order, the retardation layer includes a layer containing a cured product of a polymerizable liquid crystal compound, and both the linear polarizer and the retardation layer are , the light transmittance at a wavelength of 380 nm is 10% or less. In this specification, “joined” means a state in which two layers are in contact with each other and are adhering to each other.

The laminate of the present invention will be described with reference to FIG. 1. The laminate 10 shown in FIG. 1 includes a linear polarizing plate 11, a water-based adhesive layer 12, and a retardation layer 13. The linear polarizing plate 11 includes a protective film 14 and a polarizer 15. Although not shown, the laminate 10 may have layers other than those shown in FIG. 1, such as a bonding layer, a protect film, a front plate, and a touch panel. The polarizer 15 and the water-based adhesive layer 12 may be bonded in contact with each other. The water-based adhesive layer 12 and the retardation layer 13 may be joined by contacting each other.

In the laminate 10 of this embodiment, both the linear polarizer 11 and the retardation layer 13 have a light transmittance of 10% or less at a wavelength of 380 nm. When a water-based adhesive is used to bond a linear polarizer and a retardation layer, there are cases where thermal deterioration of the retardation layer occurs due to heating to remove moisture from the water-based adhesive. Therefore, conventionally, an active energy ray-curable adhesive has been used to bond a linear polarizer and a retardation layer. However, when the light transmittance at a wavelength of 380 nm for both the linear polarizer and the retardation layer is 10% or less, the active energy ray-curable adhesive does not harden sufficiently, and the adhesion of the linear polarizer and the retardation layer sometimes becomes insufficient. In the laminate 10 of the present invention, although the light transmittance at a wavelength of 380 nm for both the linear polarizer and the retardation layer is 10% or less, the adhesion between the layers tends to be excellent.

Both the linear polarizer 11 and the retardation layer 13 may have a light transmittance of, for example, 10% or less at a wavelength of 380 nm, or 5% or less. The light transmittance of the linear polarizer 11 and the retardation layer 13 at a wavelength of 380 nm may both be, for example, 0% or more, and are preferably 3% or more. The linear polarizer 11 and the retardation layer 13 may have the same or different light transmittance at a wavelength of 380 nm.

The laminate 10 may have an adhesion force between the linear polarizing plate 11 and the water-based adhesive layer 12 of, for example, 1.0 N/25 mm or more, preferably 1.5 N/25 mm or more, and more preferably 2.0 N/25 mm or more. It is more than 25 mm. In the laminate 10, the adhesion between the linear polarizing plate 11 and the water-based adhesive layer 12 is usually 20 N/25 mm or less, and may be, for example, 15 N/25 mm or less or 10 N/25 mm or less. Adhesion can be measured according to the method described in the Examples section below.

The laminate 10 may have an adhesion force between the retardation layer 13 and the water-based adhesive layer 12, for example, 1.0 N/25 mm or more, preferably 1.5 N/25 mm or more, and more preferably 2.0 N/2. It is more than 25 mm. In the laminate 10, the adhesion between the retardation layer 13 and the water-based adhesive layer 12 is usually 20 N/25 mm or less, and may be, for example, 15 N/25 mm or less or 10 N/25 mm or less. Adhesion can be measured according to the method described in the Examples section below.

(Linear polarizer)

The linear polarizer 11 may usually include a protective film 14 and a polarizer 15. The protective film 14 and the polarizer 15 may be bonded through a bonding layer described later, and are preferably bonded through a water-based adhesive layer. As shown in FIG. 1 , the linear polarizing plate 11 may be provided with a protective film on only one side of the polarizer 15 or may be provided with a protective film on both sides of the polarizer 15 .

(protective film)

The protective film 14 may have a function of protecting the polarizer 15 and the like. The protective film 14 is made of a light-transmitting (preferably optically transparent) thermoplastic resin, such as chain polyolefin-based resin (polypropylene-based resin, etc.), cyclic polyolefin-based resin (norbor polyolefin-based resins such as nene-based resins, etc.; Cellulose-based resins such as triacetylcellulose and diacetylcellulose; Polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polycarbonate-based resin; (meth)acrylic resins such as methyl methacrylate resins; polystyrene-based resin; polyvinyl chloride-based resin; Acrylonitrile, butadiene, and styrene-based resin; Acrylonitrile/styrene resin; polyvinyl acetate-based resin; polyvinylidene chloride-based resin; polyamide-based resin; polyacetal resin; Modified polyphenylene ether-based resin; polysulfone-based resin; polyethersulfone-based resin; polyarylate-based resin; polyamideimide-based resin; It may be a film containing a polyimide-based resin or the like.

Examples of the linear polyolefin-based resin include polyethylene resin (polyethylene resin, which is a homopolymer of ethylene, or copolymer mainly based on ethylene), polypropylene resin (polypropylene resin, which is a homopolymer of propylene, or copolymer mainly based on propylene), and In addition to homopolymers of the same chain olefin, copolymers containing two or more types of chain olefins can be mentioned.

Cyclic polyolefin-based resin is a general term for resins polymerized using cyclic olefins as polymerization units, for example, Japanese Patent Application Laid-Open No. 1-240517, Japanese Patent Application Publication No. 3-14882, and Japanese Patent Application Publication No. 3 -Resins described in Publication No. 122137, etc. may be mentioned. Specific examples of cyclic polyolefin resins include ring-opening (co)polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins and chain olefins such as ethylene and propylene (typically random copolymers), and unsaturated polymers thereof. These are graft polymers modified with carboxylic acids or their derivatives, and hydrides thereof. Among them, norbornene-based resins using norbornene-based monomers such as norbornene or polycyclic norbornene-based monomers as cyclic olefins are preferably used.

Polyester-based resin is a resin having an ester bond, excluding the cellulose ester-based resin below, and generally contains a polycondensate of polyhydric carboxylic acid or its derivative and polyhydric alcohol. As the polyhydric carboxylic acid or its derivative, a divalent dicarboxylic acid or a derivative thereof can be used, and examples include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalene dicarboxylic acid. As the polyhydric alcohol, a diol can be used, and examples include ethylene glycol, propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol. Representative examples of polyester resins include polyethylene terephthalate, which is a polycondensate of terephthalic acid and ethylene glycol.

(meth)acrylic resin is a resin whose main constituent monomer is a compound having a (meth)acryloyl group. Specific examples of (meth)acrylic resin include poly(meth)acrylic acid esters such as polymethyl methacrylate; Methyl methacrylate-(meth)acrylic acid copolymer; Methyl methacrylate-(meth)acrylic acid ester copolymer; Methyl methacrylate-acrylic acid ester-(meth)acrylic acid copolymer; (meth)acrylate methyl-styrene copolymer (MS resin, etc.); It includes copolymers of methyl methacrylate and compounds having an alicyclic hydrocarbon group (e.g., methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate-norbornyl (meth)acrylate copolymer, etc.). Preferably, a polymer containing poly(meth)acrylic acid C _1-6 alkyl ester, such as methyl poly(meth)acrylate, as the main component is used, and more preferably, a polymer containing methyl methacrylate as the main component (not less than 50% by mass or more than 100% by mass) is used. % or less, preferably 70 mass% or more and 100 mass% or less), is used.

Cellulose ester-based resin is an ester of cellulose and fatty acids. Specific examples of cellulose ester resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. Additionally, copolymers thereof and those in which part of the hydroxyl group has been modified with another substituent can also be mentioned. Among these, cellulose triacetate (triacetylcellulose) is particularly preferable.

Polycarbonate-based resin is an engineering plastic containing a polymer in which monomer units are bonded through carbonate groups.

The thickness of the protective film 14 is usually 1 μm or more and 100 μm or less, but from the viewpoint of strength, handling, etc., it is preferably 5 μm or more and 60 μm or less, more preferably 5 μm or more and 40 μm or less, and 10 μm or more. It is more preferable that it is 20 μm or less.

The moisture permeability of the protective film 14 at a temperature of 40°C and a relative humidity of 90% RH may be, for example, 200 g/m2·24 hr or less, 150 g/m2·24 hr or less, or 100 g/m2·24 hr or less. there is. The moisture permeability of the protective film 14 at a temperature of 40°C and a relative humidity of 90% RH may be, for example, 1 g/m2·24 hr or more, preferably 10 g/m2·24 hr or more, and more preferably 50 g/m2. g/㎡·24 hr or more. When the linear polarizing plate 11 is provided with protective films on both sides of the polarizer, the moisture permeability of the protective films at a temperature of 40°C and a relative humidity of 90% RH may be the same or different. The moisture permeability at a temperature of 40°C and a relative humidity of 90% RH can be measured according to the method described in the Examples section below.

The protective film 14 may have a phase difference function for purposes such as viewing angle compensation. In that case, the film itself may have a phase difference function, it may have a separate phase difference layer, or it may be a combination of both.

The protective film 14 may have the ability to absorb ultraviolet rays for the purpose of improving the light resistance of the polarizing plate. In that case, the film itself may have ultraviolet absorbing ability, may have a separate ultraviolet absorbing layer, or may be a combination of both.

When the linear polarizing plate 11 has a protective film on both sides of the polarizer, the protective film may be composed of the same type of thermoplastic resin or may be composed of a different type of thermoplastic resin. Additionally, the thickness may be the same or different. Moreover, they may have the same phase difference characteristics or may have different phase difference characteristics.

The protective film 14 has a surface treatment such as a hard coat layer, an anti-glare layer, a light diffusion layer, an anti-reflection layer, a low refractive index layer, an anti-static layer, and an anti-fouling layer on its outer surface (the surface opposite to the polarizer). It may be provided with a layer (coating layer). In addition, the thickness of the protective film includes the thickness of the surface treatment layer.

(polarizer)

Examples of the polarizer 15 include a stretched film or stretched layer to which a dichroic dye is adsorbed, and a polarizer layer formed by applying a dichroic dye and curing it. When a polarizer includes a base film and an alignment film, which will be described later, it is referred to as a polarizer including these.

As a dichroic dye, specifically, iodine and a dichroic organic dye are used. Examples of dichroic organic dyes include azo dyes. Azo pigments include, for example, C.I. These include dichroic direct dyes containing disazo compounds such as DIRECT RED 39, and dichroic direct dyes containing compounds such as trisazo and tetrakisazo.

(Stretched film or stretched layer with dichroic dye adsorbed)

Stretched films to which a dichroic dye is adsorbed are usually prepared by uniaxially stretching a polyvinyl alcohol-based resin film, dyeing the polyvinyl alcohol-based resin film with a dichroic dye, and adsorbing the dichroic dye. It can be manufactured through a process of treating the temporarily adsorbed polyvinyl alcohol-based resin film with an aqueous boric acid solution, and a process of washing with water after the treatment with the aqueous boric acid solution.

The thickness of the stretched film to which the dichroic dye is adsorbed may be, for example, 2 μm or more and 40 μm or less, 5 μm or more, 20 μm or less, further 15 μm or less, and further 10 μm or less.

Polyvinyl alcohol-based resin is obtained by saponifying polyvinyl acetate-based resin. As the polyvinyl acetate-based resin, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, a copolymer of vinyl acetate and other monomers copolymerizable with it is used. Other monomers that can be copolymerized with vinyl acetate include, for example, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth)acrylamides having an ammonium group.

The saponification degree of the polyvinyl alcohol-based resin is usually about 85 mol% or more and 100 mol% or less, and is preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes can also be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually 1,000 or more and 10,000 or less, and preferably 1,500 or more and 5,000 or less.

The stretched layer to which the dichroic dye is adsorbed is usually formed by applying a coating liquid containing the polyvinyl alcohol-based resin on a base film, a step of uniaxially stretching the obtained laminated film, and polyvinyl alcohol of the uniaxially stretched laminated film. A step of dyeing the base resin layer with a dichroic dye to adsorb the dichroic dye to form a polarizer layer, a step of treating the film with the dichroic dye adsorbed with an aqueous boric acid solution, and a step of washing with water after treatment with the aqueous boric acid solution. It can be manufactured through

If necessary, you may peel and remove the base film from the stretched layer which adsorbed the dichroic dye. The material and thickness of the base film may be the same as those of the thermoplastic resin film described later.

(Polarizer layer made by applying and curing a dichroic dye)

As a polarizer layer formed by applying and curing a dichroic dye, a layer obtained by applying a composition containing a polymerizable dichroic dye having liquid crystallinity or a composition containing a polymerizable liquid crystal compound and a dichroic dye to a base film and curing it, etc. A polarizer layer containing a cured product of a polymerizable liquid crystal compound can be mentioned. The base film may have an alignment film formed on one side. The thickness of the alignment film may be, for example, 5 nm or more and 1 μm or less.

The polarizer 15 may be incorporated into the linear polarizing plate 11 together with the base film, or may be incorporated into the linear polarizing plate 11 by peeling and removing the base film from the polarizer layer formed by applying and curing a dichroic dye. The material and thickness of the base film may be the same as the material and thickness of the protective film 14 described above. The base film may have a hard coat layer (HC layer) formed as a protective layer on at least one side.

The thickness of the polarizer layer formed by applying and curing a dichroic dye is usually 10 μm or less, preferably 8 μm or less, and more preferably 5 μm or less.

(Water-based adhesive layer)

The water-based adhesive layer 12 may be disposed between the linear polarizer 11 and the retardation layer 13 to bond them. The water-based adhesive layer 12 may be a single layer or may be a multilayer.

The water-based adhesive layer 12 may be formed of a water-based adhesive. Examples of the water-based adhesive include an adhesive containing an aqueous polyvinyl alcohol-based resin solution, a water-based two-component urethane-based emulsion adhesive, and the like. Among them, a water-based adhesive containing an aqueous polyvinyl alcohol-based resin solution is suitably used. Polyvinyl alcohol-based resins include vinyl alcohol homopolymers obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, and polyvinyl alcohol-based copolymers obtained by saponifying copolymers of vinyl acetate and other monomers copolymerizable with vinyl acetate. , or modified polyvinyl alcohol-based polymers in which their hydroxyl groups are partially modified can be used. The water-based adhesive may contain a crosslinking agent such as an aldehyde compound (glyoxal, etc.), an epoxy compound, a melamine-based compound, a methylol compound, an isocyanate compound, an amine compound, and a polyvalent metal salt.

The content of the polyvinyl alcohol-based resin in the polyvinyl alcohol-based resin aqueous solution may be, for example, 1 part by mass or more and 50 parts by mass or less, preferably 1.5 parts by mass or more and 10 parts by mass or less, more preferably 100 parts by mass of water. is 2.5 parts by mass or more and 5 parts by mass or less.

The water-based adhesive layer 12 can be formed by forming a coating film of a water-based adhesive on the linear polarizing plate 11 and then drying the coating film. When the water-based adhesive dries, the water-based adhesive layer 12 is formed. Through the water-based adhesive layer 12, the linear polarizer 11 and the retardation layer 13 are bonded. After forming the water-based adhesive layer 12 and before bonding the retardation layer 13, the surface activation treatment described later can be performed on the water-based adhesive layer 12. The surface of the retardation layer 13 can also be subjected to surface activation treatment, which will be described later. After bonding the retardation layer 13, for example, a curing process for curing the polarizing plate described later may be provided.

The thickness of the water-based adhesive layer 12 is preferably 0.1 μm or more and 1 μm or less.

(Phase difference layer)

The retardation layer 13 includes a cured layer of a polymerizable liquid crystal compound (hereinafter, also referred to as a cured layer for simplification). The cured layer is a layer that has retardation characteristics and is a layer in which a polymerizable liquid crystal compound is polymerized and cured in an aligned state to develop retardation characteristics. The retardation layer 13 may have only one layer of a cured layer of a polymerizable liquid crystal compound, or may have two or more layers of a cured layer of a polymerizable liquid crystal compound.

It is preferable that the retardation layer 13 is bonded by the cured layer directly contacting the water-based adhesive layer 12.

The retardation layer 13 may include, for example, at least one selected from the group consisting of a 1/2 wavelength retardation layer, a 1/4 wavelength retardation layer, and a positive C plate, and preferably includes a 1/4 wavelength retardation layer and a 1/4 wavelength retardation layer. It includes at least one selected from the group consisting of two-wavelength retardation layers. The retardation layer 13 may be, for example, a 1/2 wavelength retardation layer, a 1/4 wavelength retardation layer, a positive C plate, or a retardation layer laminate in which these are laminated. When two or more retardation layers are stacked, the retardation layers may be bonded to each other by a bonding layer described later. The 1/4 wavelength retardation layer preferably has reverse wavelength dispersion.

Inverse wavelength dispersion is an optical characteristic in which the liquid crystal orientation in-plane retardation value at a short wavelength is smaller than the liquid crystal orientation in-plane retardation value at a long wavelength, and preferably, the optical film satisfies the following equations (i) and (ii). It is ordered. Additionally, Re(λ) represents the in-plane retardation value for light with a wavelength of λ nm.

Re(450)/Re(550)≤1 (i)

1≤Re(630)/Re(550) (ii)

The 1/2 wavelength retardation layer is a layer whose Re(λ) satisfies Re(λ)=λ/2, and can be achieved at any wavelength in the visible light region, and in particular, it can be achieved around the wavelength of 550 nm. desirable. For the 1/2 wavelength retardation layer, it is preferable that Re(550) satisfies 200 nm≤Re(550)≤330 nm, and more preferably satisfies 220 nm≤Re(550)≤300 nm. The 1/4 wavelength retardation layer is a layer whose Re(λ) satisfies Re(λ)=λ/4, and can be achieved at any wavelength in the visible light region, and in particular, it can be achieved around the wavelength of 550 nm. desirable. For the 1/4 wavelength retardation layer, it is preferable that Re(550) satisfies 100 nm≤Re(550)≤160 nm, and more preferably satisfies 110 nm≤Re(550)≤150 nm.

Assume that the refractive index in the direction of the slow axis in the film plane (the direction in which the refractive index is maximum in the plane) is nx, the refractive index in the direction perpendicular to the slow axis in the plane and the plane is ny, and the refractive index in the thickness direction is nz. When, positive C plate satisfies the relationship of the following equation.

nz>nx≒ny

In addition, the above “≒” includes not only the case where both are completely the same, but also the case where the two are substantially the same.

When the retardation layer 13 is a retardation layer stack, it may include a first retardation layer and a second retardation layer. One of the retardation layers constituting the retardation layer laminate may be a 1/4 wavelength retardation layer, and the other may be a 1/2 wavelength retardation layer. For example, the first retardation layer and the second retardation layer may be a 1/4 wavelength retardation layer and a 1/2 wavelength retardation layer, respectively. One of the retardation layers constituting the retardation layer laminate may be a 1/4 wavelength retardation layer with reverse wavelength dispersion, and the other may be a positive C plate. For example, the first retardation layer and the second retardation layer are a 1/4 wavelength retardation layer with reverse wavelength dispersion and a positive C plate, respectively. Both the first phase difference layer and the second phase difference layer may have reverse wavelength dispersion.

Examples of the polymerizable liquid crystal compound include rod-shaped polymerizable liquid crystal compounds and disc-shaped polymerizable liquid crystal compounds. One of these may be used, or a mixture containing both of these may be used. When the rod-shaped polymerizable liquid crystal compound is horizontally or vertically aligned with respect to the base film, the optical axis of the polymerizable liquid crystal compound coincides with the long axis direction of the polymerizable liquid crystal compound. When the disc-shaped polymerizable liquid crystal compound is oriented, the optical axis of the polymerizable liquid crystal compound exists in a direction perpendicular to the disc surface of the polymerizable liquid crystal compound. As the rod-shaped polymerizable liquid crystal compound, for example, those described in Japanese Patent Publication No. Heisei 11-513019 (Claim 1, etc.) can be suitably used. Disk-shaped polymerizable liquid crystal compounds are described in Japanese Patent Application Laid-Open No. 2007-108732 (paragraphs [0020] to [0067], etc.) and Japanese Patent Application Laid-Open No. 2010-244038 (paragraphs [0013] to [0108], etc.). Those described can be suitably used.

In order for the cured layer formed by polymerizing the polymerizable liquid crystal compound to exhibit an in-plane retardation, the polymerizable liquid crystal compound may be oriented in an appropriate direction. When the polymerizable liquid crystal compound is rod-shaped, in-plane retardation is expressed by aligning the optical axis of the polymerizable liquid crystal compound horizontally with respect to the plane of the base film, which will be described later, and in this case, the optical axis direction and the slow axis direction coincide. When the polymerizable liquid crystal compound is disk-shaped, in-plane retardation is expressed by aligning the optical axis of the polymerizable liquid crystal compound horizontally with respect to the plane of the base film described later, and in this case, the optical axis and the slow axis are orthogonal. The alignment state of the polymerizable liquid crystal compound can be adjusted by combining an alignment film and the polymerizable liquid crystal compound.

A polymerizable liquid crystal compound is a compound that has at least one polymerizable group and has liquid crystallinity. When two or more types of polymerizable liquid crystal compounds are used together, it is preferable that at least one type has two or more polymerizable groups in the molecule. A polymerizable group means a group involved in a polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group refers to a group that can participate in the polymerization reaction by active radicals or acids generated from a photopolymerization initiator described later. Polymerizable groups include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group, oxetanyl group, styryl group, and allyl group. etc. can be mentioned. Among them, acryloyloxy group, methacryloyloxy group, vinyloxy group, oxiranyl group and oxetanyl group are preferable, and acryloyloxy group is more preferable. The liquid crystallinity of the polymerizable liquid crystal compound may be either thermotropic liquid crystal or lyotropic liquid crystal. If thermotropic liquid crystals are classified by degree of order, they may be nematic liquid crystal or smectic liquid crystal.

The phase contrast layer 13 may include an alignment film. The alignment film has an orientation regulating force that orients the polymerizable liquid crystal compound in a desired direction. The alignment film may be a vertical alignment film in which the molecular axis of the polymerizable liquid crystal compound is vertically aligned with respect to the base film, or may be a horizontal alignment film in which the molecular axis of the polymerizable liquid crystal compound is horizontally aligned with respect to the base film, and the molecular axis of the polymerizable liquid crystal compound may be aligned horizontally with respect to the base film. It may be an inclined alignment film that is obliquely oriented with respect to . When the phase contrast layer 13 includes two or more alignment films, the alignment films may be the same or different from each other.

The alignment film preferably has solvent resistance that does not dissolve when the composition for forming a liquid crystal layer containing a polymerizable liquid crystal compound is applied, and has heat resistance to heat treatment for removing the solvent or aligning the polymerizable liquid crystal compound. Examples of the alignment film include an orientation polymer layer formed of an orientation polymer, a photo-alignment polymer layer formed of a photo-alignment polymer, and a groove alignment film having a concavo-convex pattern or a plurality of grooves (grooves) on the layer surface.

The thickness of the cured layer included in the retardation layer 13 may be 0.1 μm or more, 0.5 μm or more, 1 μm or more, 2 μm or more, and preferably 10 μm or less, and 8 μm or less. It may be 5 ㎛ or less.

The cured layer can be formed by applying a composition for forming a liquid crystal layer containing a polymerizable liquid crystal compound onto a base film, which will be described later, drying the composition, and polymerizing the polymerizable liquid crystal compound. The composition for forming a liquid crystal layer may be applied on an alignment film formed on a base film. The base film may be the thermoplastic resin film described above.

The surface of the retardation layer 13 or the alignment film included therein that is in contact with the water-based adhesive 12 is preferably hydrophilic from the viewpoint of ensuring adhesion. An example of an index showing hydrophilicity is the contact angle with respect to water. As the contact angle with water at this time, the value after performing the surface activation treatment described later is used as an index. In order to improve adhesion, the contact angle with water is preferably 70° or less, and more preferably 60° or less. The contact angle with respect to water can be measured according to the method described in the Examples section described later.

(bonding layer)

The bonding layer may be an adhesive layer or an adhesive layer. The bonding layer, for example, bonds the first phase contrast layer and the second phase difference layer constituting the retardation layer laminate, bonds the protection film, front plate, and touch panel described later to the laminate 10, or bonds the laminate 10 It may have the function of bonding to an image display element. An adhesive layer can be disposed on one side of the laminate 10 to form a polarizing plate with an adhesive layer.

The adhesive layer can be composed of an adhesive composition containing as a main component a resin such as (meth)acrylic resin, rubber-based resin, urethane-based resin, ester-based resin, silicone-based resin, and polyvinyl ether-based resin. Among them, an adhesive composition using a (meth)acrylic resin as a base polymer, which has excellent transparency, weather resistance, heat resistance, etc., is suitable. The adhesive composition may be of an active energy ray curing type or a thermosetting type. The thickness of the adhesive layer is usually 3 μm or more and 30 μm or less, and is preferably 3 μm or more and 25 μm or less.

Examples of the (meth)acrylic resin (base polymer) used in the adhesive composition include (meth)acrylate, such as butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. A polymer or copolymer containing one or two or more types of acrylic acid ester as a monomer is suitably used. It is preferable to copolymerize a polar monomer with the base polymer. Polar monomers include, for example, (meth)acrylic acid, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, (meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate, and glycyrrhizate. Monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, etc., such as dil (meth)acrylate, can be mentioned.

The pressure-sensitive adhesive composition may contain only the base polymer, but usually further contains a crosslinking agent. Examples of the crosslinking agent include metal ions of divalence or higher, which form a metal carboxylic acid salt between carboxyl groups; A polyamine compound that forms an amide bond between carboxyl groups; A polyepoxy compound or polyol that forms an ester bond between carboxyl groups; As a polyisocyanate compound, one that forms an amide bond between carboxyl groups is exemplified. Among them, polyisocyanate compounds are preferable.

The thickness of the adhesive layer is preferably 1 μm or more and 200 μm or less, more preferably 2 μm or more and 100 μm or less, more preferably 2 μm or more and 80 μm or less, and especially preferably 3 μm or more and 50 μm or less.

The adhesive constituting the adhesive layer can be any suitable adhesive. As the adhesive, a water-based adhesive, an active energy ray-curable adhesive, etc. can be used.

The thickness when applying the adhesive can be set to any appropriate value. For example, after curing or heating (drying), it is set so that an adhesive layer with a desired thickness is obtained. The thickness of the adhesive layer is preferably 0.01 μm or more and 7 μm or less, more preferably 0.01 μm or more and 5 μm or less, further preferably 0.01 μm or more and 2 μm or less, and most preferably 0.01 μm or more and 1 μm. It is as follows.

As the water-based adhesive, the water-based adhesive described above can be used.

The active energy ray-curable adhesive is an adhesive containing a curable compound that is cured by irradiation of active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays, and is preferably an ultraviolet ray-curable adhesive.

The curable compound may be a cationically polymerizable curable compound or a radically polymerizable curable compound. Cationic polymerizable curable compounds include, for example, epoxy-based compounds (compounds having one or two or more epoxy groups in the molecule), oxetane-based compounds (compounds having one or two or more oxetane rings in the molecule), or these. There can be combinations. Examples of radically polymerizable curable compounds include (meth)acrylic compounds (compounds having one or two or more (meth)acryloyloxy groups in the molecule), other vinyl compounds having a radically polymerizable double bond, or A combination of these can be mentioned. A cationically polymerizable curable compound and a radically polymerizable curable compound may be used together. Active energy ray-curable adhesives usually further include at least one of a cationic polymerization initiator and a radical polymerization initiator for initiating a curing reaction of the curable compound.

In order to increase adhesion, surface activation treatment may be performed on at least one of the bonding surfaces of the adhesive layer and the layer bonded to the adhesive layer. Surface activation treatments include dry treatments such as corona treatment, plasma treatment, discharge treatment (glow discharge treatment, etc.), ozone treatment, UV ozone treatment, and ionizing active ray treatment (ultraviolet treatment, electron beam treatment, etc.). These surface activation treatments may be performed individually, or two or more may be combined. Among them, corona treatment is preferable. Corona treatment can be performed, for example, with an output of 1 kJ/m2 or more and 50 kJ/m2 or less. The time for performing the corona treatment may be, for example, 1 second or more and 1 minute or less.

(Protect film)

The laminate 10 can be used as a polarizing plate with a protection film by laminating a protection film to protect its surface (typically, the surface of a hard coat layer or a protective film). The protective film is peeled and removed together with the adhesive layer it has after the laminate 10 is bonded to, for example, an image display element or another optical member.

The protective film is comprised, for example, of a base film and an adhesive layer laminated thereon. For the adhesive layer, the above-described technology is cited.

Resins constituting the base film include, for example, polyethylene-based resins such as polyethylene; Polypropylene-based resins such as polypropylene; Polyester resins such as polyethylene terephthalate and polyethylene naphthalate; It may be a thermoplastic resin of polycarbonate-based resin. Preferably, it is a polyester resin such as polyethylene terephthalate.

The thickness of the protective film is not particularly limited, but is preferably in the range of 20 µm or more and 200 µm or less. When the thickness of the base material is 20 μm or more, strength tends to be easily imparted to the laminate 10.

(front panel)

As the front plate, a front plate with appropriate mechanical strength and thickness is used. Examples of such a front plate include a transparent resin plate such as polyimide resin, acrylic resin, or polycarbonate resin, or a glass plate. A functional layer such as an antireflection layer may be laminated on the viewing side of the front plate. Additionally, when the front plate is a transparent resin plate, a hard coat layer may be laminated to increase physical strength or a low moisture permeability layer may be laminated to reduce moisture permeability. The front plate can be bonded to the viewing side of the laminate 10 when the laminate 10 is bonded to an image display device.

(Touch panel)

As the touch panel, various touch panels such as resistive type, capacitive type, optical type, and ultrasonic type, as well as glass plates and transparent resin plates with a touch sensor function, are used. When a capacitive touch panel is used as a transparent member, it is preferable that a front plate made of glass or a transparent resin plate be installed closer to the viewing side than the touch panel.

(Use of laminate)

The laminate 10 can be used in an image display device. The image display device is not particularly limited and includes, for example, an organic electroluminescence (organic EL) display device, an inorganic electroluminescence (inorganic EL) display device, a liquid crystal display device, a touch panel display device, an electroluminescence display device, etc. I can hear it. The laminate 10 may be placed on the viewing side (front side) of the image display device, or may be placed on the back side.

<Method for manufacturing laminate>

The manufacturing method of the laminate of the present invention is a method of manufacturing a laminate in which a linear polarizing plate, a water-based adhesive layer, and a retardation layer are bonded in this order, and includes a first step of forming a coating film of a water-based adhesive on the linear polarizing plate; , a second step of drying the water-based adhesive film to form a water-based adhesive layer, and performing surface activation treatment on the surface of the water-based adhesive layer opposite to the linear polarizer side and the surface of the retardation layer on the water-based adhesive layer side. , a third step of bonding the linear polarizer and the retardation layer through a water-based adhesive layer is provided in this order, and both the linear polarizer and the retardation layer have a light transmittance of 10% or less at a wavelength of 380 nm. Regarding the linear polarizer, the water-based adhesive layer, and the retardation layer, respectively, the description of the linear polarizer 11, the water-based adhesive layer 12, and the retardation layer 13 in the above-described laminate 10 applies.

Conventionally, when a water-based adhesive is used to bond a linear polarizer and a retardation layer, thermal deterioration of the retardation layer sometimes occurs due to heating to remove moisture from the water-based adhesive. Therefore, conventionally, an active energy ray-curable adhesive has been used to bond a linear polarizer and a retardation layer. However, when the light transmittance at a wavelength of 380 nm for both the linear polarizer and the retardation layer is 10% or less, the active energy ray-curable adhesive does not harden sufficiently, and the adhesion of the linear polarizer and the retardation layer sometimes becomes insufficient. According to the method for manufacturing a laminate of the present invention, it is possible to manufacture a laminate having excellent adhesion between layers, even though both the linear polarizer and the retardation layer have a light transmittance of 10% or less at a wavelength of 380 nm.

The manufacturing method of the polarizing plate of the present invention will be described with reference to FIG. 2. In the first step, a coating film 26 of a water-based adhesive is formed on the polarizer 25 of the linear polarizing plate 21 provided with the protective film 24 and the polarizer 25 (FIG. 2(a)). The method of applying the water-based adhesive on the polarizer 25 can be performed by a conventionally known method.

When the polarizer 25 is a stretched film or stretched layer to which a dye having absorption anisotropy is adsorbed, the manufacturing method of the polarizer 25 is described in the description of the stretched film or stretched layer to which the dye having the above-mentioned absorption anisotropy is adsorbed. It can be manufactured as described above.

When the polarizer 25 is a film obtained by applying and curing a dye having the above-described absorption anisotropy, the polarizer 25 can be formed on a base film through an alignment film. The polarizer 25 can be formed by applying a composition for forming a polarizer containing a dichroic dye and a polymerizable liquid crystal compound and curing it. In addition to the dichroic dye and polymerizable liquid crystal compound described above, the composition for forming a polarizer preferably further contains a polymerization initiator, a leveling agent, and a solvent, and may further include a photosensitizer, a polymerization inhibitor, etc.

Application of the composition for forming a polarizer, drying, and polymerization of the polymerizable liquid crystal compound can be performed by conventionally known application methods, drying methods, and polymerization methods. For example, as a method of applying the composition for forming a polarizer, a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, and a die coating method can be adopted.

The polymerization method of the polymerizable liquid crystal compound may be selected depending on the type of polymerizable group of the polymerizable liquid crystal compound. If the polymerizable group is a photopolymerizable group, it can be polymerized by a photopolymerization method. If the polymerizable group is a thermally polymerizable group, it can be polymerized by thermal polymerization. In the present invention, photopolymerization is preferred. Since the photopolymerization method does not necessarily require heating the base film to a high temperature, a base film with low heat resistance can be used. The photopolymerization method is performed by irradiating visible light or ultraviolet light to a film containing a composition for forming a polarizer containing a polymerizable liquid crystal compound. From the viewpoint of ease of handling, ultraviolet light is preferable.

In the second step, the water-based adhesive coating film 26 is dried to form the water-based adhesive layer 22 (Figure 2(b)). The second step is a step of laminating the release film 27 on the water-based adhesive coating film 26 (Figure 2(b1)), and drying the water-based adhesive coating film 26 to form a water-based adhesive layer 22. A step of peeling the release film 27 after formation ((b2) in FIG. 2) may be further included. As a method of drying the coating film 26 of the water-based adhesive, for example, a conventionally known method can be used. The drying temperature of the water-based adhesive coating film 26 may be, for example, 20°C or higher and 90°C or lower. The drying time of the water-based adhesive coating film 26 may be, for example, 1 minute or more and 60 minutes or less.

The release film 27 is preferably comprised of a plastic film and a release layer. When drying the water-based adhesive in the third step, it is preferable that the plastic film used has a moisture permeability of 200 g/m2·24 hr or more from the viewpoint of sufficiently removing moisture from the adhesive. Examples of plastic films include triacetylcellulose resin (TAC) films. Additionally, the peeling layer can be formed, for example, from a composition for forming a peeling layer. The main component (resin) constituting the composition for forming a release layer is not particularly limited, but includes silicone resin, alkyd resin, acrylic resin, and long-chain alkyl resin.

In the third process, after surface activation treatment is applied to the surface of the water-based adhesive layer 22 on the side opposite to the linear polarizer 21 side and the surface of the retardation layer 23 on the water-based adhesive layer 22 side, the linear polarizer (21) and the retardation layer 23 are bonded through the water-based adhesive layer 22 to obtain the laminate 20 (Figure 2(c)). By performing surface activation treatment, it is possible to easily improve the adhesion between the adhesive layer 22 and the retardation layer 23 of the laminate 20. Surface activation treatments include dry treatments such as corona treatment, plasma treatment, discharge treatment (glow discharge treatment, etc.), ozone treatment, UV ozone treatment, and ionizing active ray treatment (ultraviolet treatment, electron beam treatment, etc.). These surface activation treatments may be performed individually, or two or more may be combined. Among them, corona treatment is preferable. Corona treatment can be performed, for example, with an output of 1 kJ/m2 or more and 50 kJ/m2 or less. The time for performing the corona treatment may be, for example, 1 second or more and 1 minute or less.

Although not shown, the method for manufacturing a laminate of the present invention is to easily improve the adhesion between the adhesive layer 22 and the retardation layer 23 of the laminate 20, after the third process, the laminate ( A curing process for curing 20) may be further provided. In the curing process, the laminate may be heated. In the curing process, the temperature at which the laminate 20 is heated may be, for example, 20°C or higher and 90°C or lower, preferably 40°C or higher and 90°C or lower, more preferably 60°C or higher and 90°C or lower, and is particularly preferred. Typically, it is above 75℃ and below 85℃. In the curing process, the time for curing the laminate 20 may be, for example, 1 minute or more and 2 hours or less.

Example

Hereinafter, the present invention will be described in more detail through examples. “%” and “part” in the examples are mass% and mass part, unless otherwise specified.

(Measurement of moisture permeability)

Using a constant temperature and humidity chamber, the water vapor transmission rate was measured by the moisture permeability test method (cup method, according to JIS Z 0208) under the measurement conditions of temperature 40°C, relative humidity 90% RH, and measurement time of 24 hours. The measured water vapor transmission rate was taken as the water vapor transmission rate at a temperature of 40°C and a relative humidity of 90% RH.

(Measurement of light transmittance)

The linear polarizer and retardation layer were cut to a size of 30 mm x 30 mm, and the transmittance [%] was measured between wavelengths of 200 and 510 nm. For the measurement, an ultraviolet-visible spectrophotometer "UV-2450" manufactured by Shimazu Seisakusho Co., Ltd. was used.

(Measurement of thickness)

The thickness of the layer was measured using a contact-type film thickness measuring device (“MS-5C” manufactured by Nikon Corporation). The thickness of the water-based adhesive layer and the polarizer were measured using a laser microscope (“OLS3000” manufactured by Olympus Corporation).

(Evaluation of adhesion)

The laminate was cut to a width of 25 mm to obtain a measurement sample. Using a precision universal testing machine "Autograph AGS-50NX" manufactured by Shimazu Seisakusho Co., Ltd., the retardation layer side of the measurement sample was adhered to a glass plate through an adhesive. Adhesion was measured by holding the protective film of the measurement sample and measuring the force at the time of peeling in the 180° direction. The measurement was performed in an environment with a peeling speed of 300 mm/min, a temperature of 23 ± 2°C, and a relative humidity of 50 ± 5%. The evaluation criteria are shown below.

A: Adhesion was good, and the portion of the layer captured during measurement was damaged.

B: It was possible to measure the adhesion by peeling off the film during measurement.

C: The sample peeled off before measurement, and adhesion could not be evaluated.

(Measurement of contact angle for water)

The contact angle with respect to water after surface treatment under the same conditions as when producing the laminate is the contact angle with respect to water of the measurement object. That is, after corona treatment was performed on the surface of the retardation layer at 14 kJ/m2, a contact angle meter (Kyowa Kaimen Chemical Co., Ltd., image processing contact angle meter “FACE”) was used so that the corona-treated surface became the upper surface. It was set horizontally on a "CA-

(Production of polarizer)

A polyvinyl alcohol film with an average degree of polymerization of about 2400 and a degree of saponification of 99.9 mol% or more and a thickness of 30 ㎛ was immersed in pure water at 30°C and then immersed in an aqueous solution at 30°C with a mass ratio of iodine:potassium iodine:water of 0.02:2:100. Iodine staining was performed by immersion (hereinafter also referred to as iodine dyeing process). The polyvinyl alcohol film that had gone through the iodine dyeing process was immersed in an aqueous solution of potassium iodide: boric acid: water at a mass ratio of 12:5:100 at 56.5°C to perform boric acid treatment (hereinafter also referred to as boric acid treatment process). The polyvinyl alcohol film that had undergone the boric acid treatment step was washed with pure water at 8°C and then dried at 65°C to obtain a polarizer (thickness after stretching: 12 μm) in which iodine was adsorbed and oriented in polyvinyl alcohol. At this time, stretching was performed in the iodine dyeing process and boric acid treatment process. The total stretching ratio in this stretching was 5.3 times.

(Production of water-based adhesive)

A water-based adhesive was obtained by adding 3 parts by mass of a polyvinyl alcohol-based resin to 100 parts by mass of water and mixing with stirring.

(Preparation of active energy ray-curable adhesive)

The following ingredients were combined and mixed, and then defoamed to prepare an active energy ray-curable adhesive.

[Cationic polymerizable compound]

・Neopentyl glycol diglycidyl ether (Product name: EX-211L, manufactured by Nagase Chemtex Co., Ltd.) 30 parts by mass

·3-Ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane (Product name: OXT-221, manufactured by Toagosei Co., Ltd.) 13 parts by mass

Bisphenol A type epoxy resin (Product name: EP-4100E, ADEKA Co., Ltd., viscosity 13 Pa·s (temperature 25°C)) 12 parts by mass

·Aromatic-containing oxetane compound (Product name: TCM-104, manufactured by TRONLY) 45 parts by mass

[Photocationic polymerization initiator]

·CPI-100P, manufactured by San-Apro Co., Ltd., 50% propylene carbonate solution 2.25 parts by mass (solid content)

[Photosensitization preparation]

·1,4-diethoxynaphthalene 1 part by mass

(Fabrication of 1/4 wavelength retardation layer 1)

A base film containing a polyethylene terephthalate resin (PET) film (thickness 100 ㎛, temperature 40°C, moisture permeability 13 g/m2·24 hr at 90% RH relative humidity) was prepared. A rubbing treatment was performed on the base film to form an alignment film (1 ㎛ thick). On the alignment film, a composition for forming a liquid crystal layer containing a rod-shaped nematic polymerizable liquid crystal compound (liquid crystal monomer) was applied and solidified by irradiation with ultraviolet rays while maintaining refractive index anisotropy. In this way, a 1/4 wavelength retardation layer 1 with reverse wavelength dispersion as a cured layer of the polymerizable liquid crystal compound with a thickness of 1 μm was formed on the alignment layer of the base film. The light transmittance of the reverse wavelength dispersion 1/4 wavelength retardation layer 1 at a wavelength of 380 nm was 1%, and the contact angle with respect to water was 58°.

(Fabrication of 1/4 wavelength retardation layer 2)

A base film containing a triacetylcellulose resin (TAC) film (thickness 40 ㎛, temperature 40°C, moisture permeability 950 g/m2·24 hr at relative humidity 90% RH) was prepared. A rubbing treatment was performed on the base film to form an alignment film (1 ㎛ thick). On the alignment film, a composition for forming a liquid crystal layer containing a rod-shaped nematic polymerizable liquid crystal compound (liquid crystal monomer) was applied and solidified by irradiation with ultraviolet rays while maintaining refractive index anisotropy. In this way, the 1/4 wavelength retardation layer 2 with constant wavelength dispersion as a cured layer of the polymerizable liquid crystal compound with a thickness of 1 μm was formed on the alignment layer of the base film. The light transmittance of the 1/4 wavelength retardation layer 2 with constant wavelength dispersion at a wavelength of 380 nm was 1%, and the contact angle with respect to water was 76°.

(Production of positive C plate)

A base film containing a polyethylene terephthalate resin (PET) film (thickness 38 ㎛, temperature 40°C, moisture permeability 16 g/m2·24 hr at 90% RH relative humidity) was prepared. The composition for forming a vertical alignment film was applied to one side of the base film to a film thickness of 3 μm, and irradiated with ultraviolet rays of 200 mJ/cm 2 to produce a vertical alignment film. A composition for forming a positive C plate containing a polymerizable liquid crystal compound is applied onto the vertical alignment film, and after drying, the coating film is irradiated with ultraviolet rays (UV) to polymerize the polymerizable liquid crystal compound to form a cured layer of the polymerizable liquid crystal compound. By doing so, a positive C plate was obtained. The light transmittance of the cured layer at a wavelength of 380 nm was 85%, and the contact angle with water was 63°.

(Production of phase contrast layer laminate with base film)

Corona treatment was performed on the surface of the 1/4 wavelength retardation layer 1 on the base film and the surface of the positive C plate on the base film. Each corona-treated surface was bonded using the active energy ray-curable adhesive prepared above. Afterwards, from the positive C plate side, using an ultraviolet irradiation device (manufactured by Fusion UV Systems Co., Ltd.), ultraviolet rays are irradiated with an integrated light amount of 400 mJ/cm2 (UV-B) to cure the active energy ray curable adhesive. An adhesive layer was formed. Bonding was performed using a laminator, and the active energy ray-curable adhesive was applied so that the thickness of the adhesive layer after curing was 3 μm. As a result, a retardation layer laminate with a base film was obtained, comprising the base film, alignment film, 1/4 wavelength retardation layer 1, active energy ray-curable adhesive layer, positive C plate, vertical alignment film, and base film in this order.

<Example 1>

A water-based adhesive is applied to one side of the polarizer, and a first protective film (water vapor permeability of 13 g/m2·24 hr, light transmittance of 6% at a wavelength of 380 nm, manufactured by Nippon Zeon Co., Ltd., containing an ultraviolet absorber) is applied to one side of the polarizer. Cyclic polyolefin resin (COP) film “Zeonoa ZF12”, thickness 13 μm] was bonded to obtain a laminate having the layer structure of first protective film/adhesive layer (thickness 0.1 μm)/polarizer.

Next, a water-based adhesive was applied to the surface of the polarizer opposite to the first protective film side, and a coating film of the water-based adhesive was formed.

After that, a release film (triacetylcellulose resin (TAC) film subjected to release treatment, thickness 25 ㎛) was laminated on the water-based adhesive coating film, and dried in an air atmosphere at a temperature of 80°C for 5 minutes, then the release film. was peeled off to obtain a water-based adhesive layer with a thickness of 0.1 μm.

After corona treatment was performed on the water-based adhesive layer and the 1/4 wavelength retardation layer 1 at 14 kJ/m 2, the cured layer side of the 1/4 wavelength retardation layer 1 was bonded. The base film used to form the 1/4 wavelength retardation layer 1 was peeled. A laminate having a layer structure of first protective film/adhesive layer/polarizer/water-based adhesive layer/cured layer/alignment film was obtained. The results are shown in Table 1.

<Example 2>

A laminate was produced in the same manner as in Example 1, except that 1/4 wavelength retardation layer 2 was used instead of 1/4 wavelength retardation layer 1. The results are shown in Table 1.

<Example 3>

In Example 1, a retardation layer laminate with a base film was used instead of the 1/4 wavelength retardation layer 1, and the base film on the 1/4 wavelength retardation layer side was peeled and exposed from the retardation layer laminate with a base film. A laminate was produced in the same manner as in Example 1, except that the alignment film and the water-based adhesive layer were bonded. The results are shown in Table 1.

<Comparative Example 1>

A laminate was produced in the same manner as in Example 1, except that corona treatment was not performed on either the water-based adhesive layer or the retardation layer. The results are shown in Table 1.

10: Laminate 11, 21: Polarizer
12, 22: water-based adhesive layer 13, 23: phase difference layer
14: protective film 15: polarizer
24: protective film 25: polarizer
26: Coating film of water-based adhesive 27: Release film

Claims (9)

A linear polarizer, a water-based adhesive layer, and a retardation layer are bonded in this order,
The retardation layer includes a layer containing a cured product of a polymerizable liquid crystal compound,
A laminate in which both the linear polarizer and the retardation layer have a light transmittance of 10% or less at a wavelength of 380 nm. The laminate according to claim 1, wherein the water-based adhesive layer and a layer containing a cured product of the polymerizable liquid crystal compound are in contact with each other and joined. The method of claim 1 or 2, wherein the linear polarizer is provided with a protective film on one or both sides of the polarizer,
A laminate wherein the protective film has a moisture permeability of 200 g/m2·24 hr or less at a temperature of 40°C and a relative humidity of 90% RH. The laminate according to any one of claims 1 to 3, wherein the retardation layer includes a 1/4 wavelength retardation layer. The laminate according to any one of claims 1 to 4, wherein the retardation layer includes a 1/2 wavelength retardation layer. The laminate according to any one of claims 1 to 5, wherein the retardation layer includes only one layer containing a cured product of a polymerizable liquid crystal compound. A method for manufacturing a laminate in which a linear polarizer, a water-based adhesive layer, and a retardation layer are bonded in this order,
A first step of forming a coating film of a water-based adhesive on the linear polarizer,
A second step of drying the water-based adhesive film to form a water-based adhesive layer;
After performing surface activation treatment on the surface of the water-based adhesive layer opposite to the linear polarizer side and the surface of the retardation layer on the water-based adhesive layer side, the linear polarizer and the retardation layer are bonded through the water-based adhesive layer. 3 process
Provided in this order,
A method for producing a laminate wherein both the linear polarizer and the retardation layer have a light transmittance of 10% or less at a wavelength of 380 nm. The method of manufacturing a laminated body according to claim 7, further comprising a step of heating the laminated body after the third step. The method of claim 7 or 8, wherein the second process is,
A step of laminating a release film on the water-based adhesive coating film;
A process of peeling off the release film after drying the coating film of the water-based adhesive.
A method of manufacturing a laminate further comprising: