Laminate and method for producing the same

Abstract

The purpose of this invention is to provide a laminate and its manufacturing method, wherein either the linear polarizer or the retardation layer constituting the laminate has a transmittance of less than 10% at a wavelength of 380 nm, and the adhesion between the linear polarizer and the retardation layer is also good when a water-based adhesive is used. The present invention provides a laminate in which a linear polarizer, an aqueous adhesive layer and a phase retardation layer are sequentially bonded together, and the phase retardation layer is a layer containing a hardened material of a polymeric liquid crystal compound. Both the linear polarizer and the phase retardation layer have a transmittance of less than 10% at a wavelength of 380 nm.

Description

[Technical Field]

[0001] This invention relates to a laminate, and more particularly to a method for manufacturing a laminate. [Previous Technology]

[0002] In Patent Document 1, a polarizing plate with a phase retardation layer having a polarizer and a phase retardation layer has been proposed.

[0002] [Previous Technical Documents]

[0002] [Patent Documents]

[0003] [Patent Document] Japanese Patent Application Publication No. 2018-017996

[0004] In laminates comprising a linear polarizer and a retardation layer, active energy linear curing adhesives are often used to bond the linear polarizer and the retardation layer. When the transmittance of either the linear polarizer or the retardation layer is low, sometimes it is not possible to achieve sufficient interlayer adhesion.

[0005] Most active energy linear curing adhesives are types of adhesives that utilize light in the ultraviolet wavelength region for curing. When either the linear polarizer or the retardation layer being bonded has low transmittance in the ultraviolet wavelength region, sometimes it is not possible to achieve sufficient interlayer adhesion.

[0005] Furthermore, when using an adhesive that is cured with light in the visible light wavelength region with high transmittance of a linear polarizing plate and a phase difference layer, it is necessary to take measures on the production equipment side in order to prevent the adhesive from curing unexpectedly, and it is difficult to apply.

[0006] The purpose of this invention is to provide a laminate and a method for manufacturing the same, wherein the linear polarizer and the retardation layer constituting the laminate have good adhesion when the transmittance at a wavelength of 380 nm is less than 10%.

[0007] The present invention provides the following laminate and a method for manufacturing the laminate.

[0007] [1] A laminate, comprising a linear polarizer, an aqueous adhesive layer and a phase difference layer sequentially bonded together.

[0007] The aforementioned phase retardation layer comprises a hardened material containing a polymeric liquid crystal compound.

[0007] The transmittance of either the aforementioned linear polarizer or the aforementioned phase difference layer at a wavelength of 380 nm is less than 10%.

[0007] [2] As described in [1], the aforementioned aqueous adhesive layer is bonded to and adhered to the layer system containing the aforementioned polymeric liquid crystal compound.

[0007] [3] As described in [1] or [2], wherein the aforementioned linear polarizer has a protective film on one or both sides of the polarizer.

[0007] The aforementioned protective film has a moisture permeability of less than 200g / m2‧24hr.

[0007] [4] A stack as described in any one of [1] to [3], wherein the aforementioned phase difference layer comprises a 1 / 4 wavelength phase difference layer.

[0007] [5] A stack as described in any one of [1] to [4], wherein the aforementioned phase difference layer comprises a 1 / 2 wavelength phase difference layer.

[0007] [6] The laminate as described in any one of [1] to [5] is a layer consisting of only one layer of a hardened material containing a polymeric liquid crystal compound.

[0007] [7] A method for manufacturing a laminate, comprising sequentially bonding a linear polarizer, an aqueous adhesive layer and a phase retardation layer to form a laminate, wherein the manufacturing method comprises, in sequence:

[0007] The first step is to form a coating of water-based adhesive on the aforementioned linear polarizing plate;

[0007] Step 2 is to dry the aforementioned water-based adhesive coating to form a water-based adhesive layer;

[0007] The third step is to perform surface activation treatment on the surface of the aforementioned water-based adhesive layer that is opposite to the aforementioned linear polarizer side and the surface of the aforementioned phase difference layer that is before the aforementioned water-based adhesive layer, and then attach the aforementioned linear polarizer and the aforementioned phase difference layer through the aforementioned water-based adhesive layer.

[0007] The transmittance of either the aforementioned linear polarizer or the aforementioned phase difference layer at a wavelength of 380 nm is less than 10%.

[0007] [8] The method for manufacturing a laminate as described in [7] further includes, after the aforementioned third step, a step of heating the aforementioned laminate.

[0007] [9] The method for manufacturing a laminate as described in [7] or [8], wherein the aforementioned second step further comprises:

[0007] The step of depositing a release film on the coating of the aforementioned water-based adhesive;

[0007] After the coating of the aforementioned water-based adhesive has dried, the aforementioned release film is peeled off.

[0008] According to the present invention, the objective is to provide a laminate and a method for manufacturing the same, wherein when the transmittance of either the linear polarizer or the retardation layer constituting the laminate is less than 10% at a wavelength of 380nm, the adhesion between the linear polarizer and the retardation layer is also good. [Simplified Explanation of the Diagram]

[0009] FIG1 shows a schematic cross-sectional view of an example of the layer structure of the laminate of the present invention.

[0009] FIG2 shows a schematic cross-sectional view of an example of a method for manufacturing a laminate of the present invention.

Implementation Method

[0010] 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 the following drawings, the scale has been appropriately adjusted for ease of understanding of each component, and the scale of each component shown in the drawings may not be consistent with the scale of the actual component.

[0011] The lamination system of the present invention sequentially laminates a linear polarizer, an aqueous adhesive layer, and a retardation layer. The retardation layer is a layer comprising a cured material containing a polymeric liquid crystal compound, and both the linear polarizer and the retardation layer have a transmittance of less than 10% at a wavelength of 380 nm. In this specification, "laminated" means that the two layers are in contact with each other and are bonded together.

[0012] The laminate of the present invention will be described with reference to the drawings. The laminate 10 shown in FIG. 1 includes a linear polarizer 11, an aqueous adhesive layer 12, and a retardation layer 13. The linear polarizer 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: an adhesive layer, a protective film, a panel, and a touch panel. The polarizer 15 and the aqueous adhesive layer 12 can contact and adhere to each other. The aqueous adhesive layer 12 and the retardation layer 13 can contact and adhere to each other.

[0013] In the laminate 10 of this embodiment, the transmittance of either the linear polarizer 11 or the retardation layer 13 at a wavelength of 380 nm is 10% or less. When an aqueous adhesive is used to bond the linear polarizer and the retardation layer, thermal degradation of the retardation layer sometimes occurs due to heating to remove moisture from the aqueous adhesive. Therefore, active energy line-curing adhesives have traditionally been used to bond the linear polarizer and the retardation layer. However, when the transmittance of either the linear polarizer or the retardation layer at a wavelength of 380 nm is 10% or less, the active energy line-curing adhesive sometimes fails to cure sufficiently, resulting in insufficient adhesion between the linear polarizer and the retardation layer. In the laminate 10 of the present invention, even though the transmittance of either the linear polarizer or the retardation layer at a wavelength of 380 nm is 10% or less, there is a tendency for excellent interlayer adhesion.

[0014] The transmittance of either the linear polarizer 11 or the retardation layer 13 at a wavelength of 380 nm can be, for example, less than 10%, or less than 5%. The transmittance of either the linear polarizer 11 or the retardation layer 13 at a wavelength of 380 nm can be, for example, more than 0%, and preferably more than 3%. The transmittance of the linear polarizer 11 and the retardation layer 13 at a wavelength of 380 nm can be the same or different.

[0015] The adhesion strength between the laminate 10, the linear polarizer 11, and the aqueous adhesive layer 12 can be, for example, 1.0 N / 25 mm or more, preferably 1.5 N / 25 mm or more, and even more preferably 2.0 N / 25 mm or more. The adhesion strength between the laminate 10, the linear polarizer 11, and the aqueous adhesive layer 12 is typically 20 N / 25 mm or less, for example, 15 N / 25 mm or less, or 10 N / 25 mm or less. The adhesion strength can be measured according to the method described in the following embodiments.

[0016] The adhesion strength between the phase retardation layer 13 and the aqueous adhesive layer 12 in the laminate 10 can be, for example, 1.0 N / 25 mm or more, preferably 1.5 N / 25 mm or more, and even more preferably 2.0 N / 25 mm or more. The adhesion strength between the phase retardation layer 13 and the aqueous adhesive layer 12 in the laminate 10 is typically 20 N / 25 mm or less, for example, 15 N / 25 mm or less, or 10 N / 25 mm or less. The adhesion strength can be measured according to the method described in the following section of the embodiments.

[0017] (Linear polarizer)

[0017] The linear polarizer 11 typically includes a protective film 14 and a polarizer 15. The protective film 14 and the polarizer 15 are bonded together through an adhesive layer described later, preferably through a water-based adhesive layer. As shown in Figure 1, the linear polarizer 11 may have a protective film on only one side of the polarizer 15, or it may have protective films on both sides of the polarizer 15.

[0018] (Protective film)

[0018] The protective film 14 series can have the function of protecting the polarizer 15, etc. The protective film 14 series can be a film made of a thermoplastic resin with light transmittance (preferably optical transparency), such as polyolefin resins like chain polyolefin resins (polypropylene resins, etc.), cyclic polyolefin resins like nobornene resins, cellulose resins like triacetyl cellulose and diacetyl cellulose, polyester resins like polyethylene terephthalate and polybutylene terephthalate, polycarbonate resins, (meth)acrylic resins like methyl methacrylate resins, polystyrene resins, polyvinyl chloride resins, acrylonitrile / butadiene / styrene resins, acrylonitrile / styrene resins, polyvinyl acetate resins, polyvinylidene chloride resins, polyamide resins, polyacetal resins, modified polyphenylene ether resins, polyurethane resins, polyether ether resins, polyaromatic ester resins, polyamide-imide resins, and polyimide resins.

[0019] In addition to homopolymers of chain olefins such as polyethylene resin (a homopolymer of ethylene or a copolymer with ethylene as the main component) and polypropylene resin (a homopolymer of propylene or a copolymer with propylene as the main component), copolymers composed of two or more chain olefins may also be listed.

[0020] Cyclic polyolefin resins are a general term for resins polymerized using cyclic olefins as polymerizing units. Examples include resins described in Japanese Patent Application Publication Nos. 1-240517, 3-14882, and 3-122137. Specific examples of cyclic polyolefin resins include: ring-opening (co)polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins with chain olefins such as ethylene and propylene (represented as random copolymers), graft polymers modified with unsaturated carboxylic acids or their derivatives, and their hydrogenates. Preferably, a nobornene resin using nobornene monomers such as norbornene or polycyclic nobornene monomers as the cyclic olefin is used.

[0021] Polyester resins, excluding the cellulose ester resins described below, are generally composed of resins having ester bonds and polycarboxylic acids or their derivatives, and polyols, forming condensation polymers. The polycarboxylic acids or their derivatives can be divalent dicarboxylic acids or their derivatives, such as terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylate. The polyols can be divalent diols, such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol, and cyclohexanediol. A representative example of a polyester resin is polyethylene terephthalate, which is a condensation polymer of terephthalic acid and ethylene glycol.

[0022] (Meth)acrylic resins are resins in which compounds having (meth)acrylic groups are the main constituent monomers. Specific examples of (meth)acrylic resins include, for example: poly(meth)acrylates such as polymethyl methacrylate; methyl methacrylate-(meth)acrylate copolymers; methyl methacrylate-(meth)acrylate copolymers; methyl methacrylate-acrylate-(meth)acrylate copolymers; methyl methacrylate-styrene copolymers (MS resin, etc.); copolymers of methyl methacrylate with compounds having alicyclic hydrocarbon groups (e.g., methyl methacrylate-cyclohexyl methacrylate copolymers, methyl methacrylate-norborneol methacrylate copolymers, etc.). Preferably, a polymer with poly(meth)acrylate C1-6 alkyl esters such as poly(meth)acrylate as the main component is used, more preferably, a methyl methacrylate resin with methyl methacrylate as the main component (50% by mass to 100% by mass, preferably 70% by mass to 100% by mass).

[0023] Cellulose ester resins are esters of cellulose and fatty acids. Specific examples of cellulose ester resins include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. Also, copolymers of these, or those in which a portion of the hydroxyl group is modified with other substituents, can be listed. Among these, cellulose triacetate (triacetylated cellulose) is particularly preferred.

[0024] Polycarbonate resins are engineering plastics composed of polymers in which monomer units are bonded together with carbonate groups.

[0025] The thickness of the protective film 14 is usually between 1 μm and 100 μm, but from the point of view of strength or operability, it is better to be between 5 μm and 60 μm, even better to be between 5 μm and 40 μm, and even better to be between 10 μm and 20 μm.

[0026] The permeability of the protective film 14 at a temperature of 40°C and a relative humidity of 90%RH can be, for example, less than 200 g / m²·24hr, less than 150 g / m²·24hr, or less than 100 g / m²·24hr. The permeability of the protective film 14 at a temperature of 40°C and a relative humidity of 90%RH can be, for example, greater than 1 g / m²·24hr, preferably greater than 10 g / m²·24hr, and more preferably greater than 50 g / m²·24hr. When the linear polarizer 11 has protective films on both sides of the polarizer, the permeability of the protective films at a temperature of 40°C and a relative humidity of 90%RH can be the same or different. The permeability at a temperature of 40°C and a relative humidity of 90%RH can be measured according to the method described in the section of the embodiments described later.

[0027] For purposes such as viewing angle compensation, the protective film 14 can have a phase difference function. In this case, the film itself can have a phase difference function, or it can have a phase difference layer, or it can be a combination of the two.

[0028] The protective film 14 is designed to improve the lightfastness of the polarizing plate and may have ultraviolet absorption energy. In this case, the film itself may have ultraviolet absorption energy, or it may have an additional ultraviolet absorption layer, or it may be a combination of the two.

[0029] When the linear polarizer 11 has protective films on both sides of the polarizer, the protective films can be made of the same type of thermoplastic resin or different types of thermoplastic resin. Furthermore, the thickness can be the same or different. Moreover, they can have the same phase difference characteristics or different phase difference characteristics.

[0030] The protective film 14 may be a surface treatment layer (coating layer) having on its outer surface (the side opposite to the polarizer) a hard coating layer, an anti-glare layer, a light diffusion layer, an anti-reflection layer, a low refractive index layer, an antistatic layer, or an anti-fouling layer. Furthermore, the thickness of the protective film includes the thickness of the surface treatment layer.

[0031] (Polarizing film)

[0031] Polarizing film 15 may include an extended film or extended layer adsorbed with dichroic pigment, a polarizing film layer formed by coating with dichroic pigment and then curing it. When a polarizing film includes the substrate film and the alignment film described later, it is called a polarizing film including these.

[0032] Specifically, as a dichroic pigment, iodine or a dichroic organic dye is used. Examples of dichroic organic dyes include azo pigments. Among azo pigments, examples include dichroic direct dyes composed of diazo compounds such as CI Direct Red 39, and dichroic direct dyes composed of compounds such as triazo and tetraazo.

[0033] (Extended membrane or extended layer with adsorbed dichroic pigment)

[0033] An extended film adsorbed with a dichroic pigment can generally be manufactured by the following steps: a step of uniaxially extending a polyvinyl alcohol-based resin film; a step of dyeing the polyvinyl alcohol-based resin film with a dichroic pigment to adsorb the dichroic pigment; a step of treating the polyvinyl alcohol-based resin film adsorbed with the dichroic pigment with a boric acid aqueous solution; and a step of washing with water after treatment with the boric acid aqueous solution.

[0033] The thickness of the extended film adsorbed with dichroic pigment can be, for example, more than 2 μm and less than 40 μm, more than 5 μm, less than 20 μm, less than 15 μm, and even less than 10 μm.

[0034] Polyvinyl alcohol-based resins are obtained by saponifying polyvinyl acetate-based resins. Polyvinyl acetate-based resins can be copolymers of vinyl acetate and other monomers that can be copolymerized with vinyl acetate, in addition to polyvinyl acetate homopolymers. Examples of other monomers that can be copolymerized with vinyl acetate include: unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth)acrylamides containing ammonium groups.

[0035] The degree of saponification of polyvinyl alcohol (PVA) resins is typically between 85 mol% and 100 mol%, preferably above 98 mol%. PVA resins can be modified, for example, using aldehyde-modified polyethylene formaldehyde or polyethylene acetal. The degree of polymerization of PVA resins is typically between 1000 and 10000, preferably between 1500 and 5000.

[0036] The extended layer adsorbed with dichroic pigment can generally be manufactured by the following steps: applying a coating solution containing the above-mentioned polyvinyl alcohol resin onto a substrate film; uniaxially extending the resulting laminated film; dyeing the polyvinyl alcohol resin layer of the uniaxially extended laminated film with dichroic pigment to adsorb the dichroic pigment to form a polarizing film layer; treating the film adsorbed with dichroic pigment with a boric acid aqueous solution; and washing with water after treatment with boric acid aqueous solution.

[0036] If necessary, the substrate film can be peeled off from the extension layer on which the dichroic pigment is adsorbed. The material and thickness of the substrate film can be the same as those of the thermoplastic resin film described later.

[0037] (A polarizing film layer formed by coating with dichroic pigments and then hardening it)

[0037] Examples of polarizer layers formed by coating and curing dichroic pigments include: a polarizer layer containing a composition of a polymeric dichroic pigment with liquid crystal properties, or a layer obtained by coating a composition containing a polymeric liquid crystal compound and a dichroic pigment onto a substrate film and curing it; and other polarizer layers containing a polymeric liquid crystal compound. An alignment film may be provided on one side of the substrate film. The thickness of the alignment film may, for example, be 5 nm or more and 1 μm or less.

[0038] The polarizer 15 can be assembled into the linear polarizer 11 together with the substrate film, or it can be assembled into the linear polarizer 11 by peeling off the substrate film from the polarizer layer formed by coating with dichroic pigments and then curing it. The material and thickness of the substrate film can be the same as those of the protective film 14. The substrate film can have a hard coating (HC layer) formed on at least one side as a protective layer.

[0039] The thickness of the polarizing film layer formed by coating with dichroic pigments and hardening it is usually less than 10 μm, preferably less than 8 μm, and even more preferably less than 5 μm.

[0040] (Water-based adhesive layer)

[0040] In order to bond the linear polarizer 11 and the phase retardation layer 13, an aqueous adhesive layer 12 can be disposed between the two. The aqueous adhesive layer 12 can be a single layer or multiple layers.

[0041] The aqueous adhesive layer 12 may be formed by an aqueous adhesive. Examples of aqueous adhesives include adhesives composed of aqueous solutions of polyvinyl alcohol resins and aqueous two-component ethyl carbamate emulsion adhesives. Among these, aqueous adhesives composed of aqueous solutions of polyvinyl alcohol resins are suitable. In addition to polyvinyl alcohol homopolymers obtained by saponifying polyvinyl acetate homopolymers, polyvinyl alcohol copolymers obtained by saponifying copolymers of vinyl acetate and other monomers that can copolymerize with vinyl acetate, or modified polyvinyl alcohol polymers whose hydroxyl groups have been partially modified, may also be used. Aqueous adhesives may include crosslinking agents such as aldehyde compounds (glyoxal, etc.), epoxy compounds, melamine compounds, hydroxymethyl compounds, isocyanate compounds, amine compounds, and polyvalent metal salts.

[0042] The content of polyvinyl alcohol resin in the aqueous solution of polyvinyl alcohol resin relative to 100 parts by mass of water may be, for example, more than 1 part by mass and less than 50 parts by mass, more preferably more than 1.5 parts by mass and less than 10 parts by mass, and even more preferably more than 2.5 parts by mass and less than 5 parts by mass.

[0043] The aqueous adhesive layer 12 is formed by forming a coating of aqueous adhesive on the linear polarizer 11 and then drying the coating. The aqueous adhesive layer 12 is formed by drying the aqueous adhesive. The linear polarizer 11 and the phase retardation layer 13 are bonded together with the aqueous adhesive layer 12 in between. After forming the aqueous adhesive layer 12 and before bonding the phase retardation layer 13, the aqueous adhesive layer 12 may be subjected to a surface activation treatment described later. The surface of the phase retardation layer 13 may also be subjected to a surface activation treatment described later. After bonding the phase retardation layer 13, for example, a curing step for curing the polarizer described later may be provided.

[0044] The thickness of the water-based adhesive layer 12 is preferably between 0.1 μm and 1 μm.

[0045] (Phase difference layer)

[0045] The phase retardation layer 13 comprises a hardened layer of polymeric liquid crystal compound (hereinafter, it may also be simply referred to as the hardened layer). The hardened layer is a layer with phase retardation characteristics, which is a layer in which the polymeric liquid crystal compound is polymerized and hardened in an oriented state to exhibit phase retardation characteristics. The phase retardation layer 13 may be a hardened layer of polymeric liquid crystal compound consisting of only one layer, or it may consist of two or more hardened layers of polymeric liquid crystal compound.

[0046] The phase difference layer 13 is preferably a hardened layer that is directly bonded to the water-based adhesive layer 12.

[0047] The retardation layer 13 may, for example, contain 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, preferably containing at least one selected from the group consisting of a 1 / 4 wavelength retardation layer and a 1 / 2 wavelength retardation layer. The retardation layer 13 may, for example, be a 1 / 2 wavelength retardation layer, a 1 / 4 wavelength retardation layer, a positive C-plate, or a laminate containing such retardation layers. When two or more retardation layers are laminated, the retardation layers can be bonded to each other by bonding layers described later. The 1 / 4 wavelength retardation layer preferably has inverse wavelength dispersion.

[0048] The so-called inverse wavelength dispersion refers to the optical characteristic that the phase difference in the liquid crystal alignment plane at short wavelengths is smaller than the phase difference in the liquid crystal alignment plane at long wavelengths. Preferably, the optical film satisfies the following equations (i) and (ii). Furthermore, Re(λ) represents the in-plane phase difference for light with a wavelength of λnm.

[0048] Re(450) / Re(550)≦1 (i)

[0048] 1≦Re(630) / Re(550) (ii)

[0049] The 1 / 2 wavelength phase retardation layer Re(λ) satisfies Re(λ) = λ / 2, and can be achieved in any wavelength in the visible light region, with a preferred system being achieved around 550 nm. A preferred 1 / 2 wavelength phase retardation layer Re(550) satisfies 200 nm ≤ Re(550) ≤ 330 nm, and a more preferred system satisfies 220 nm ≤ Re(550) ≤ 300 nm. The 1 / 4 wavelength phase retardation layer Re(λ) satisfies Re(λ) = λ / 4, and can be achieved in any wavelength in the visible light region, with a preferred system being around 550 nm. A preferred 1 / 4 wavelength phase retardation layer Re(550) satisfies 100 nm ≤ Re(550) ≤ 160 nm, and a more preferred system satisfies 110 nm ≤ Re(550) ≤ 150 nm.

[0050] When the refractive index in the slow axis direction (the direction with the largest refractive index in the plane) is set as nx, the refractive index in the direction orthogonal to the slow axis in the plane is set as ny, and the refractive index in the thickness direction is set as nz, the positive C plate system satisfies the following relationship.

[0050] nz>nx≒ny

[0050] Furthermore, the above "≒" not only refers to the case where the two are completely identical, but also includes the case where the two are substantially identical.

[0051] When the phase difference layer 13 is a phase difference stack, it may include a first phase difference layer and a second phase difference layer. One of the phase difference layers constituting the phase difference stack is a 1 / 4 wavelength phase difference layer, and the other may be a 1 / 2 wavelength phase difference layer. For example, the first phase difference layer and the second phase difference layer may be a 1 / 4 wavelength phase difference layer and a 1 / 2 wavelength phase difference layer, respectively. One of the phase difference layers constituting the phase difference stack is a 1 / 4 wavelength phase difference layer with inverse wavelength dispersion, and the other may be a positive C-plate. For example, the first phase difference layer and the second phase difference layer may be a 1 / 4 wavelength phase difference layer with inverse wavelength dispersion and a positive C-plate, respectively. Either the first phase difference layer or the second phase difference layer may have inverse wavelength dispersion.

[0052] Examples of polymerizable liquid crystal compounds include rod-shaped and disc-shaped polymerizable liquid crystal compounds. One of these can be used, or a mixture containing both can be used. When a rod-shaped polymerizable liquid crystal compound is horizontally or vertically oriented relative to a substrate film, the optical axis of the polymerizable liquid crystal compound is aligned with the long axis direction of the polymerizable liquid crystal compound. When a disc-shaped polymerizable liquid crystal compound is oriented, its optical axis exists in a direction orthogonal to the disc surface of the polymerizable liquid crystal compound. Rod-shaped polymerizable liquid crystal compounds are suitable for use, for example, those described in Japanese Patent Application Publication No. 11-513019 (claim 1, etc.). The disc-shaped polymeric liquid crystal compound is suitable for use with respect to the descriptions in Japanese Patent Application Publication No. 2007-108732 (paragraphs

[0020] to

[0067] , etc.) and Japanese Patent Application Publication No. 2010-244038 (paragraphs

[0013] to

[0108] , etc.).

[0053] The hardened layer formed by polymerizing the polymeric liquid crystal compound exhibits in-plane phase difference simply by orienting the polymeric liquid crystal compound in a suitable direction. When the polymeric liquid crystal compound is rod-shaped, its optical axis is horizontally oriented relative to the plane of the substrate film described later to exhibit in-plane phase difference. In this case, the optical axis direction is consistent with the [u2] slow axis direction. When the polymeric liquid crystal compound is disk-shaped, its optical axis is horizontally oriented relative to the plane of the substrate film described later to exhibit in-plane phase difference. In this case, the optical axis and the slow axis are orthogonal. The orientation state of the polymeric liquid crystal compound can be adjusted by combining the alignment film and the polymeric liquid crystal compound.

[0054] A polymerizable liquid crystal compound is a compound having at least one polymerizable group and exhibiting liquid crystal properties. When two or more polymerizable liquid crystal compounds are used together, it is preferable that at least one type has two or more polymerizable groups within its molecule. A polymerizable group refers to a group that participates in the polymerization reaction, preferably a photopolymerizable group. Here, a photopolymerizable group refers to a group that can participate in the polymerization reaction via an active free radical or acid generated from a photopolymerization initiator described later. Examples of polymerizable groups include: vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloxy, methacryloxy, oxopropyl, oxobutyl, styryl, allyl, etc. Among these, acryloxy, methacryloxy, vinyloxy, oxopropyl, and oxobutyl are preferred, with acryloxy being more preferred. Polymerizable liquid crystal compounds can be thermotropic or liquidotropic. When thermotropic liquid crystals are classified in order, they can be nematic liquid crystals or lamellar liquid crystals.

[0055] The retardation layer 13 may include an alignment film. The alignment film has an alignment restraint force that orients the polymerizable liquid crystal compound in a desired direction. The alignment film may be a vertical alignment film that orients the molecular axis of the polymerizable liquid crystal compound perpendicularly to the substrate film, a horizontal alignment film that orients the molecular axis of the polymerizable liquid crystal compound horizontally to the substrate film, or an inclined alignment film that orients the molecular axis of the polymerizable liquid crystal compound tilted relative to the substrate film. When the retardation layer 13 includes two or more alignment films, the alignment films may be identical or different from each other.

[0056] Preferably, the alignment film is solvent-resistant and does not dissolve through coating of a liquid crystal layer composition containing a polymeric liquid crystal compound, and has heat resistance to solvent removal or heat treatment for alignment of the polymeric liquid crystal compound. Examples of alignment films include: an alignment polymer layer formed of an alignment polymer, a photoalignment polymer layer formed of a photoalignment polymer, and a groove alignment film having a concave-convex pattern or a plurality of grooves on the layer surface.

[0057] The thickness of the hardened layer in the phase difference layer 13 may be 0.1 μm or more, 0.5 μm or more, 1 μm or more, or 2 μm or more, and preferably 10 μm or less, or 8 μm or less, or 5 μm or less.

[0058] The hardening layer can be formed by coating a liquid crystal layer forming composition containing a polymeric liquid crystal compound onto a substrate film described later and drying it to polymerize the polymeric liquid crystal compound. The liquid crystal layer forming composition can be coated onto an alignment film formed on the substrate film. The substrate film can be the thermoplastic resin film described above.

[0059] From the viewpoint of ensuring adhesion, the surface in contact with the aqueous adhesive 12 of the phase retardation layer 13 or the orientation film contained therein is preferably hydrophilic. An example of an indicator of hydrophilicity is the water contact angle. The water contact angle is the value obtained after applying the surface activation treatment described later. For good adhesion, the water contact angle is preferably 70° or less, and more preferably 60° or less. The water contact angle can be measured according to the method described in the section of the embodiments described later.

[0060] (Adhesive Layer)

[0060] The bonding layer may be an adhesive layer or an adhesive layer. For example, the bonding layer may have the following functions: bonding the first phase difference layer and the second phase difference layer constituting the phase difference layer laminate; or, bonding the protective film, panel, and touch panel after the laminate 10 is bonded; or, bonding the laminate 10 to an image display element. An adhesive layer may be disposed on one side of the laminate 10 to form a polarizing plate with an adhesive layer.

[0061] The adhesive layer system can be composed of an adhesive composition with resins such as (meth)acrylic resins, rubber resins, ethyl carbamate resins, ester resins, polysiloxane resins, and polyvinyl ether resins as the main component. Preferably, the adhesive composition uses a (meth)acrylic resin as the base polymer, which has excellent transparency, weather resistance, and heat resistance. The adhesive composition can be of the active energy linear curing type or the thermosetting type. The thickness of the adhesive layer is typically 3 μm to 30 μm, preferably 3 μm to 25 μm.

[0062] The (meth)acrylate resin (base polymer) used in the adhesive composition may, for example, be a polymer or copolymer using one or more (meth)acrylate monomers such as butyl (meth)acrylate, ethyl (meth)acrylate, isooctyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. In the base polymer, it is preferable to copolymerize polar monomers. Examples of polar monomers include, for example, monomers having carboxyl, hydroxyl, acetyl, amino, or epoxy groups such as (meth)acrylate, 2-hydroxypropyl (meth)acrylate, hydroxyethyl (meth)acrylate, methacrylamide, N,N-dimethylaminoethyl (meth)acrylate, and glycidyl (meth)acrylate.

[0063] The adhesive composition may contain only the aforementioned base polymer, but usually also contains a crosslinking agent. Examples of crosslinking agents include: divalent or higher metal ions that form a carboxylic acid metal salt with a carboxyl group; polyamine compounds that form an amide bond with a carboxyl group; polyepoxide compounds or polyols that form an ester bond with a carboxyl group; and polyisocyanate compounds that form an amide bond with a carboxyl group. Polyisocyanate compounds are preferred.

[0064] The thickness of the adhesive layer is preferably 1 μm to 200 μm, more preferably 2 μm to 100 μm, even more preferably 2 μm to 80 μm, and especially preferably 3 μm to 50 μm.

[0065] The adhesive constituting the adhesive layer can be any suitable adhesive. The adhesive can be a water-based adhesive, an active energy line curing adhesive, etc.

[0066] The thickness of the adhesive coating can be set to any suitable value. For example, after curing or heating (drying), the thickness can be set to obtain an adhesive layer with a desired thickness. The thickness of the adhesive layer is preferably 0.01 μm to 7 μm, more preferably 0.01 μm to 5 μm, even more preferably 0.01 μm to 2 μm, and most preferably 0.01 μm to 1 μm.

[0067] The above-mentioned water-based adhesive can be used as a water-based adhesive.

[0068] The so-called active energy line curing adhesive is an adhesive containing a curing compound that is cured by irradiation with active energy lines such as ultraviolet light, visible light, electron beams, and X-rays, and is preferably an ultraviolet curing adhesive.

[0069] The aforementioned curing compound may be a cationicly polymerizable curing compound or a free radical polymerizable curing compound. Examples of cationicly polymerizable curing compounds include: epoxy compounds (compounds having one or more epoxy groups in the molecule), or cyclobutane compounds (compounds having one or more cyclobutane rings in the molecule), or combinations thereof. Examples of free radical polymerizable curing compounds include: (meth)acrylic acid compounds (compounds having one or more (meth)acrylic acid groups in the molecule), or other vinyl compounds having double bonds with free radical polymerizable properties, or combinations thereof. Cationicly polymerizable curing compounds and free radical polymerizable curing compounds may be used together. Active energy linear curing adhesives generally further include at least one of a cationic polymerization initiator and a free radical polymerization initiator for initiating the curing reaction of the aforementioned curing compound.

[0070] To improve adhesion, a surface activation treatment may be applied to at least one of the bonding surfaces of the adhesive layer and the layer adhered to the adhesive layer. Examples of surface activation treatments include: corona treatment, plasma treatment, discharge treatment (glow discharge treatment, etc.), ozone treatment, UV ozone treatment, and dry treatments such as ionization active line treatment (ultraviolet treatment, electron beam treatment, etc.). These surface activation treatments may be performed individually or in combination of two or more. Corona treatment is preferred. For example, corona treatment may be performed with an output of 1 kJ / m² to 50 kJ / m². The duration of the corona treatment may be, for example, 1 second to 1 minute.

[0071] (Protective film)

[0071] The laminate 10 can be formed into a polarizing plate with a protective film by laminating a protective film used to protect its surface (typically the surface of a hard coating or protective film). The protective film is, for example, completely peeled off by peeling off the adhesive layer thereon after the image display element or other optical component is attached to the laminate 10.

[0072] The protective film is, for example, composed of a substrate film and an adhesive layer deposited thereon. The adhesive layer is described in the above description.

[0072] The resin constituting the substrate film may be, for example, polyethylene resin such as polyethylene; polypropylene resin such as polypropylene; polyester resin such as polyethylene terephthalate or polyethylene naphthalate; polycarbonate resin; or thermoplastic resin. Polyester resin such as polyethylene terephthalate is preferred.

[0073] The thickness of the protective film is not particularly limited, but it is preferable to set it in the range of 20 μm to 200 μm. If the thickness of the substrate is 20 μm or more, there is a tendency to easily impart strength to the laminate 10.

[0074] (Panel)

[0074] The panel can be made of a material with appropriate mechanical strength and thickness. Examples of such panels include transparent resin sheets made of polyimide resin, acrylic resin, or polycarbonate resin, or glass sheets. An anti-reflective layer or other functional layer can also be laminated on the recognition side of the panel. Furthermore, when the panel is a transparent resin sheet, a hard coating to improve physical strength or a low-permeability layer to reduce moisture permeability can be laminated. When the panel is attached to the laminate 10 in the image display device, it can be attached to the recognition side of the laminate 10.

[0075] (Touchpad)

[0075] The touchpad can be any type of touchpad, such as resistive film, capacitive, optical, or ultrasonic, or a glass or transparent resin plate with touch sensor functionality. When using a capacitive touchpad as a transparent component, it is preferable to place a panel made of glass or transparent resin plate closer to the sensing side than the touchpad itself.

[0076] (Applications of laminated bodies)

[0076] The laminate 10 can be used in an image display device. The image display device is not particularly limited, and examples include: organic electroluminescent (organic EL) display devices, inorganic electroluminescent (inorganic EL) display devices, liquid crystal display devices, touchpad display devices, electroluminescent display devices, etc. The laminate 10 can also be disposed on the recognition side (front side) or the rear side of the image display device.

[0077] <Manufacturing Method of Laminated Materials>

[0077] The method for manufacturing the laminate of the present invention is a method for manufacturing a laminate formed by sequentially bonding a linear polarizing plate, an aqueous adhesive layer, and a phase retardation layer, wherein the manufacturing method comprises, in sequence:

[0077] Step 1 involves forming a water-based adhesive coating on the linear polarizer; Step 2 involves drying the water-based adhesive coating to form a water-based adhesive layer; Step 3 involves applying surface activation treatment to the surface of the water-based adhesive layer opposite to the linear polarizer side and the surface of the phase retardation layer opposite to the water-based adhesive layer side, and then bonding the linear polarizer and the phase retardation layer together with the water-based adhesive layer in between; the transmittance of either the linear polarizer or the phase retardation layer at a wavelength of 380 nm is 10% or less. The description of the linear polarizer, the water-based adhesive layer, and the phase retardation layer applies to the linear polarizer 11, the water-based adhesive layer 12, and the phase retardation layer 13 of the above-mentioned laminate 10, respectively.

[0078] Conventionally, when using aqueous adhesives to bond the linear polarizer and the retardation layer, the heating process used to remove moisture from the aqueous adhesive sometimes causes thermal degradation of the retardation layer. Therefore, conventionally, active energy line-curing adhesives have been used to bond the linear polarizer and the retardation layer. However, when the transmittance of either the linear polarizer or the retardation layer at a wavelength of 380 nm is less than 10%, the active energy line-curing adhesive may not cure sufficiently, resulting in insufficient adhesion between the linear polarizer and the retardation layer. According to the manufacturing method of the laminate of the present invention, even when the transmittance of either the linear polarizer or the retardation layer at a wavelength of 380 nm is less than 10%, a laminate with excellent interlayer adhesion can be manufactured.

[0079] A method for manufacturing the polarizing plate of the present invention will be described with reference to FIG2. In the first step, a coating 26 of water-based adhesive is formed on the polarizing plate 25 of the linear polarizing plate 21 having a protective film 24 and a polarizing plate 25 [FIG. 2(a)]. The method of applying the water-based adhesive to the polarizing plate 25 can be carried out by conventionally known methods.

[0080] If the polarizer 25 is an extended film or extended layer that adsorbs anisotropic pigments, the manufacturing method of the polarizer 25 can be carried out as described in the above description of an extended film or extended layer that adsorbs anisotropic pigments.

[0081] When the polarizer 25 is a film formed by coating and curing a pigment with the above-mentioned anisotropic absorption properties, the polarizer 25 can be formed on a substrate film with an alignment film in between. The polarizer 25 can be formed by coating a polarizer forming composition containing a dichroic pigment and a polymerizable liquid crystal compound and curing it. In addition to the above-mentioned dichroic pigment and polymerizable liquid crystal compound, the polarizer forming composition preferably further includes a polymerization initiator, a leveling agent, a solvent, and may further include a photosensitizer, a polymerization inhibitor, etc.

[0082] The coating, drying, and polymerization of the composition for polarizing film formation can be carried out by conventionally known coating, drying, and polymerization methods. For example, the coating method for the composition for polarizing film formation can be wire rod coating, extrusion coating, direct gravure coating, reverse gravure coating, and die-cut coating, etc.

[0083] The polymerization method for the polymerizable liquid crystal compound can be selected simply according to the type of polymerizable group in the polymerizable liquid crystal compound. If the polymerizable group is a photopolymerizable group, polymerization can be carried out by photopolymerization. If the polymerizable group is a thermally polymerizable group, polymerization can be carried out by thermal polymerization. In this invention, photopolymerization is preferred. Photopolymerization does not necessarily require heating the substrate film to a high temperature, so a substrate film with low heat resistance can be used. Photopolymerization is carried out by irradiating a film composed of a polarizer composition containing the polymerizable liquid crystal compound with visible light or ultraviolet light. From the perspective of ease of operation, ultraviolet light is preferred.

[0084] In the second step, the water-based adhesive coating 26 is dried to form a water-based adhesive layer 22 [Fig. 2(b)]. The second step may further include the step of depositing a release film 27 on the water-based adhesive coating 26 [Fig. 2(b1)], and the step of peeling off the release film 27 after drying the water-based adhesive coating 26 to form the water-based adhesive layer 22 [Fig. 2(b2)]. The method for drying the water-based adhesive coating 26 can be, for example, by a conventionally known method. The drying temperature of the water-based adhesive coating 26 can be, for example, 20°C or higher and 90°C or lower. The drying time of the water-based adhesive coating 26 can be, for example, 1 minute or higher and 60 minutes or lower.

[0085] The release film 27 is preferably composed of a plastic film and a release layer. In step 3, when drying the aqueous adhesive, from the viewpoint of sufficiently removing moisture from the adhesive, the plastic film used preferably has a moisture permeability of 200 g / m²‧24hr or higher. Examples of plastic films include, for example, triacetyl cellulose resin (TAC) films. Furthermore, the release layer can be formed, for example, from a release layer forming composition. The main component (resin) constituting the release layer forming composition is not particularly limited, but examples include polysiloxane resins, alkyd resins, acrylic resins, and long-chain alkyl resins.

[0086] In step 3, after applying surface activation treatment to the surface of the aqueous adhesive layer 22 opposite to the linear polarizer 21 side and the surface of the phase retardation layer 23 on the aqueous adhesive layer 22 side, the linear polarizer 21 and the phase retardation layer 23 are bonded together with the aqueous adhesive layer 22 in between to obtain the laminate 20 [Fig. 2(c)]. By applying surface activation treatment, the adhesion between the adhesive layer 22 and the phase retardation layer 23 of the laminate 20 can be easily improved. Examples of surface activation treatments include: corona treatment, plasma treatment, discharge treatment (glow discharge treatment, etc.), ozone treatment, UV ozone treatment, and dry treatment such as ionization active line treatment (ultraviolet treatment, electron beam treatment, etc.). These surface activation treatments can be performed individually or in combination of two or more. Among them, corona treatment is preferred. Corona treatment can be performed, for example, with an output of 1kJ / m2 to 50kJ / m2. The duration of corona treatment can be, for example, more than 1 second and less than 1 minute.

[0087] Although not illustrated, the manufacturing method of the laminate of the present invention is designed to easily improve the adhesion between the adhesive layer 22 and the phase difference layer 23 of the laminate 20. Therefore, after the third step, a curing step for curing the laminate 20 can be added. In the curing step, the laminate can be heated. In the curing step, the temperature of heating the laminate 20 can 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 particularly preferably 75°C or higher and 85°C or lower. In the curing step, the curing time of the laminate 20 can be, for example, 1 minute or higher and 2 hours or lower.

[0087] [Example]

[0088] Hereinafter, the present invention will be described in more detail by way of examples. Unless otherwise specified, "%" and "parts" in the examples refer to mass percentage and mass parts.

[0089] (Measurement of moisture permeability)

[0089] Using a constant temperature and humidity bath, the water vapor transmission rate was determined under the following conditions: temperature 40°C, relative humidity 90%RH, and measurement time 24 hours, by means of a water vapor transmission rate test method (cup method, according to JIS Z 0208). The measured water vapor transmission rate was set as the water vapor transmission rate at a temperature of 40°C and a relative humidity of 90%RH.

[0090] (Measurement of light transmittance)

[0090] The linear polarizing plate and the phase retardation layer were cut to a size of 30mm × 30mm, and the transmittance [%] was measured at wavelengths between 200 and 510nm. The measurements were performed using a Shimadzu UV-2450 ultraviolet-visible spectrophotometer manufactured by Shimadzu Corporation.

[0091] (Thickness Measurement) The thickness of the

[0091] layer was measured using a contact film thickness measuring device (NIKON Corporation "MS-5C"). The thickness of the aqueous adhesive layer and the polarizer was measured using a laser microscope (OLYMPUS Corporation "OLS3000").

[0092] (Assessment of Adhesion)

[0092] Test samples were obtained by cutting the laminate into 25mm wide pieces. Using a Shimadzu Corporation precision universal testing machine, the phase difference layer side of the test sample was attached to a glass plate with an adhesive in between. The adhesion was measured by holding the sample from the protective film to the aqueous adhesive layer and measuring the force applied during peeling in a 180° direction. The test was conducted at a peeling speed of 300mm / min, a temperature of 23±2℃, and a relative humidity of 50±5%. The evaluation criteria are presented below.

[0092] A: The adhesion is good, and the part of the layer that was grasped during the test was damaged.

[0092] B: The membrane is peeled off during the measurement to determine the adhesion.

[0092] C: If the sample peels off before the test, the adhesion cannot be assessed.

[0093] (Measurement of water contact angle)

[0093] The water contact angle of the object being measured is the water contact angle after surface treatment under the same conditions as when the laminate was made. That is, after corona treatment of the surface of the phase difference layer at 14 kJ / m2, the corona-treated surface is placed on top, and the contact angle meter (FACE CA-X type image processing contact angle meter manufactured by Kyowa Interface Science Co., Ltd.) is placed horizontally. 1 μL of pure water is dropped at the measurement position, and the water contact angle is measured by the θ / 2 method.

[0094] (Production of Polarizing Film)

[0094] A polyvinyl alcohol (PVA) film with an average degree of polymerization of approximately 2400, a saponification degree of 99.9 mol% or higher, and a thickness of 30 μm was immersed in pure water at 30°C, and then immersed in an aqueous solution at 30°C containing iodine, potassium iodide, and water at a mass ratio of 0.02:2:100 for iodine staining (hereinafter, also referred to as the iodine staining step). The PVA film after the iodine staining step was immersed in an aqueous solution at 56.5°C containing potassium iodide, boric acid, and water at a mass ratio of 12:5:100 for boric acid treatment (hereinafter, also referred to as the boric acid treatment step). The PVA film after the boric acid treatment step was washed with pure water at 8°C and dried at 65°C to obtain a polarizer with iodine adsorption oriented on PVA (extended thickness of 12 μm). At this time, extension was performed in the iodine staining step and the boric acid treatment step. The total extension ratio was 5.3 times.

[0095] (Preparation of water-based adhesives)

[0095] A water-based adhesive is obtained by adding 3 parts by weight of polyvinyl alcohol resin relative to 100 parts by weight of water and stirring.

[0096] (Preparation of active energy line-curing adhesive)

[0096] After preparing and mixing the following components, [u3] degassing is performed to prepare an active energy line-curing adhesive.

[0096] [Catonic polymerizable compounds]

[0096] ‧Neopentyl glycol diglycidyl ether (trade name: EX-211L, manufactured by NAGASECHEMTEX Co., Ltd.) 30 parts by weight

[0096] ‧3-Ethyl-3{[(3-ethyloxocyclobutane-3-yl)methoxy]methyl}oxocyclobutane (trade name: OXT-221, manufactured by Dong-A Synthetic Co., Ltd.) 13 parts by weight

[0096] ‧Bisphenol A type epoxy resin (trade name: EP-4100E, ADEKA Co., Ltd., viscosity 13 Pa‧s (temperature 25℃)) 12 parts by weight

[0096] ‧Aromatic cyclobutane compound (trade name: TCM-104, manufactured by TRONLY) 45 parts by weight

[0096] [Photocationic Polymerization Initiator]

[0096] ‧CPI-100P, manufactured by SAN-APRO Co., Ltd., 2.25 parts by weight of 50% propyl carbonate solution

[0096] (Solid component)

[0096] [Photosensitive Additive]

[0096] ‧1 part by weight of 1,4-diethoxynaphthalene

[0097] (Fabrication of 1 / 4 wavelength phase difference layer 1)

[0097] A substrate film composed of polyethylene terephthalate (PET) film (100 μm thick, 40°C, 90% RH, and a transmittance of 13 g / m²‧24hr) is prepared. An alignment film (1 μm thick) is formed by rubbing the substrate film. A liquid crystal layer forming composition comprising rod-shaped nematic polymeric liquid crystal compounds (liquid crystal monomers) is coated onto the alignment film, and ultraviolet light is irradiated and cured while maintaining anisotropic refractive index. In this manner, a 1 μm thick, reverse-wavelength dispersion 1-quarter-wavelength retardation layer 1, serving as a hardened layer of the polymeric liquid crystal compound, is formed on the alignment film of the substrate film. The reverse-wavelength dispersion 1-quarter-wavelength retardation layer 1 has a transmittance of 1% at a wavelength of 380 nm and a water contact angle of 58°.

[0098] (Fabrication of 1 / 4 wavelength phase difference layer 2)

[0098] A substrate film composed of a triacetyl cellulose resin (TAC) film (thickness 40 μm, temperature 40°C, relative humidity 90%RH, transmittance 950 g / m²‧24hr) is prepared. An alignment film (thickness 1 μm) is formed by rubbing the substrate film. A liquid crystal layer forming composition containing rod-shaped nematic polymeric liquid crystal compounds (liquid crystal monomers) is coated onto the alignment film, and ultraviolet light is irradiated and cured while maintaining anisotropic refractive index. In this manner, a 1 μm thick, positively wavelength-dispersed 1 / 4 wavelength retardation layer 2, serving as a hardened layer of the polymeric liquid crystal compound, is formed on the alignment film of the substrate film. The positively wavelength-dispersed 1 / 4 wavelength retardation layer 2 has a transmittance of 1% at a wavelength of 380 nm and a water contact angle of 76°.

[0099] (Production of the C-plate)

[0099] A substrate film composed of polyethylene terephthalate (PET) film (thickness 38 μm, temperature 40°C, relative humidity 90%RH, and permeability 16 g / m²‧24hr) is prepared. A vertically oriented film is prepared by coating a vertically oriented film forming composition on one side of the substrate film to a film thickness of 3 μm and irradiating it with ultraviolet light at 200 mJ / cm². A positive C-plate forming composition containing a polymerizable liquid crystal compound is coated on the vertically oriented film. After drying, the coating is irradiated with ultraviolet light (UV) to polymerize the polymerizable liquid crystal compound and form a hardened layer of the polymerizable liquid crystal compound, thus obtaining a positive C-plate. The hardened layer has a transmittance of 85% at a wavelength of 380 nm and a water contact angle of 63°.

[0100] (Fabrication of phase difference laminate of substrate film)

[0100] Corona treatment was applied to the surface of the 1 / 4 wavelength retardation layer 1 on the substrate film and the surface of the positive C-plate on the substrate film. The corona-treated surfaces were then bonded together using the aforementioned active energy line-curing adhesive. Subsequently, from the positive C-plate side, the active energy line-curing adhesive was cured by ultraviolet irradiation using a UV irradiation device [manufactured by FUSION UV SYSTEMS Co., Ltd.] at a cumulative light intensity of 400 mJ / cm² (UV-B), forming an adhesive layer. The bonding was performed using a laminator, and the active energy line-curing adhesive was coated to form a cured adhesive layer with a thickness of 3 μm. This resulted in a retardation laminate containing, in sequence, the substrate film, the alignment film, the 1 / 4 wavelength retardation layer 1, the active energy line-curing adhesive layer, the positive C-plate, the vertical alignment film, and the substrate film.

[0101] <Example 1>

[0101] A water-based adhesive is coated on one side of a polarizer, and a first protective film [13 g / m2‧24hr, 6% transmittance at 380 nm wavelength, cyclic polyolefin resin (COP) film "ZEONOR ZF12" containing ultraviolet absorber, manufactured by ZEON Corporation of Japan, with a thickness of 13 μm] is laminated on one side of the polarizer to obtain a laminate consisting of a first protective film / adhesive layer (thickness 0.1 μm) / polarizer.

[0101] Then, a water-based adhesive is applied to the surface of the polarizer that is opposite to the side of the first protective film to form a coating of water-based adhesive.

[0101] After this, a release film [a triacetyl cellulose resin (TAC) film with a thickness of 25 μm that has undergone release treatment] is deposited on the coating of the water-based adhesive. After drying in an atmospheric environment at a temperature of 80°C for 5 minutes, the release film is peeled off to obtain a water-based adhesive layer with a thickness of 0.1 μm.

[0101] After applying corona treatment at 14 kJ / m² to the aqueous adhesive layer and the quarter-wavelength retardation layer 1, the hardened layer side of the quarter-wavelength retardation layer 1 was bonded together. The substrate film used for forming the quarter-wavelength retardation layer 1 was peeled off. A laminate consisting of a first protective film / adhesive layer / polarizer / aqueous adhesive layer / hardened layer / orientation film was obtained. The results are shown in Table 1.

[0102] <Example 2>

[0102] In Example 1, except that a 1 / 4 wavelength phasing layer 2 was used instead of a 1 / 4 wavelength phasing layer 1, the laminate was fabricated in the same manner as in Example 1. The results are shown in Table 1.

[0103] <Example 3>

[0103] In Example 1, except that a phase retardation layer laminate with a substrate film was used to replace the 1 / 4 wavelength phase retardation layer 1, and the substrate film on the 1 / 4 wavelength phase retardation layer side was peeled off from the phase retardation layer laminate with a substrate film and the exposed orientation film was bonded to the aqueous adhesive layer, the laminate was fabricated in the same manner as in Example 1. The results are shown in Table 1.

[0104] <Comparative Example 1>

[0104] Except for Example 1, in which neither the aqueous adhesive layer nor the phase difference layer was subjected to corona treatment, the laminates were fabricated in the same manner as in Example 1. The results are shown in Table 1.

[0105] [Table 1]

Claims

1. A laminate comprising a linear polarizer, an aqueous adhesive layer and a phase retardation layer sequentially bonded together, wherein the phase retardation layer comprises a cured material containing a polymeric liquid crystal compound, and either the linear polarizer or the phase retardation layer has a transmittance of less than 10% at a wavelength of 380 nm.

2. The stack as described in claim 1, wherein, The aforementioned aqueous adhesive layer is bonded and adhered to the aforementioned layer system containing the polymeric liquid crystal compound.

3. A stack as described in claim 1 or 2, wherein, The aforementioned linear polarizing plate has a protective film on one or both sides of the polarizer, and the aforementioned protective film has a permeability of less than 200g / m2・24hr at a temperature of 40°C and a relative humidity of 90%RH.

4. A laminate as described in claim 1 or 2, wherein, The aforementioned phase difference layer includes a 1 / 4 wavelength phase difference layer.

5. A laminate as described in claim 1 or 2, wherein, The aforementioned phase difference layer includes a 1 / 2 wavelength phase difference layer.

6. A laminate as described in claim 1 or 2, wherein, The aforementioned phase retardation layer system has only one layer containing a hardened material of a polymeric liquid crystal compound.

7. A method for manufacturing a laminate, comprising sequentially bonding a linear polarizer, an aqueous adhesive layer, and a retardation layer to form a laminate, the method comprising the following steps: a first step of forming an aqueous adhesive coating on the linear polarizer; a second step of drying the aqueous adhesive coating to form an aqueous adhesive layer; a third step of performing surface activation treatment on the surface of the aqueous adhesive layer opposite to the linear polarizer side and the surface of the retardation layer preceding the aqueous adhesive layer, and then bonding the linear polarizer and the retardation layer together with the aqueous adhesive layer in between; wherein the transmittance of either the linear polarizer or the retardation layer at a wavelength of 380 nm is 10% or less.

8. A method for manufacturing a laminate as described in claim 7, wherein, Following the aforementioned third step, there is a further step of heating the aforementioned laminated body.

9. A method for manufacturing a laminate as described in claim 7 or 8, wherein, The aforementioned second step further includes: the step of depositing a release film on the aforementioned water-based adhesive coating film; and the step of peeling off the aforementioned release film after the aforementioned water-based adhesive coating film has dried.

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