TWI689572B - Optical laminate and liquid crystal display - Google Patents

Abstract

The present invention provides an optical laminate and a display in which bubbles at the end of adhesive layer under high temperature environment are not easy be generated, and which has excellent visibility. The optical laminate of this invention comprise, a substrate, an active energy ray-curable binding layer, a polarizing plate and an adhesive layer in this order, wherein, the active energy ray-curable binding layer covering the side surface of the polarizing plate and the adhesive layer. All polymerizable monomer contained in an active energy ray-curable binder for forming the active energy ray-curable binding layer, has a diffusion coefficient of 1.2×10^-8cm²/s or less in the adhesive layer.

Description

Optical laminate and liquid crystal display device

The invention relates to an optical laminate and a liquid crystal display device.

The liquid crystal display device is incorporated in various devices such as mobile devices such as mobile phones, personal computers, and even large TVs. In mobile devices such as mobile phones, cover glass or cover glass with a touch sensor module (hereinafter referred to as a touch panel) is mostly arranged on the surface of the recognition side. Between the control panel and the liquid crystal panel, Liquid Optically Clear Adhesives (hereinafter referred to as LOCA) is disposed and hardened. By using LOCA, it is possible to suppress the entrapment of air bubbles between the liquid crystal panel and the protective glass or touch panel, and reduce the loss of light due to reflection.

Patent Literature 1 discloses a technique for a display device in which a transparent cover sheet is attached to a liquid crystal panel through an adhesive agent, wherein the adhesive agent covers all side peripheral surfaces of the polarizing plate constituting the liquid crystal panel. By covering the side peripheral surface of the polarizing plate with an adhesive, the problem that the moisture in the atmosphere invades from the side peripheral surface of the polarizing plate and causes expansion near the end of the polarizing plate is solved.

Prior technical literature Patent Literature

[Patent Document 1] Japanese Patent Laid-Open No. 2009-69321

When the technology disclosed in Patent Document 1 is applied to manufacture a display device, the following problem reappears: In a high-temperature environment, bubbles are generated at the end of the adhesive layer to impair visibility. According to the results of in-depth research conducted by the present inventors, it is clear that the reasons are as follows: because the side peripheral surface of the adhesive layer used to attach the polarizing plate to the liquid crystal cell and the adhesive are in contact with each other, the adhesive is hardened During this period, the monomers, oligomers, etc. in the adhesive will penetrate into the adhesive layer. In a high-temperature environment, the monomers, oligomers, etc. that have penetrated into the adhesive layer are vaporized to form tiny bubbles. As a result, an area where tiny bubbles are formed, because the bubbles scatter light, the visibility of the end of the adhesive layer is impaired.

The present invention includes the following items.

[1] An optical laminate comprising, in order, a substrate, an active energy ray-curable adhesive layer, a polarizing plate, and an adhesive layer, wherein the active energy ray-curable adhesive layer covers the polarizing plate and the adhesive On the side surface of the layer, the polymerizable monomer contained in the active energy ray-curable adhesive composition forming the active energy ray-curable adhesive layer has a diffusion coefficient of 1.2×10 ^-8 cm in the adhesive layer ² /s or less.

[2] The optical laminate according to [1], wherein the weight reduction rate of the active energy ray-curable adhesive composition after being left in an environment of 100° C. for 24 hours is 50% or less.

[3] A liquid crystal display device having the optical laminate according to [1] or [2].

According to the present invention, it is possible to provide an optical laminate and a display device which are difficult to generate bubbles at the end of the adhesive layer under a high-temperature environment and have excellent visibility.

1‧‧‧ substrate

2‧‧‧ Active energy ray hardening adhesive layer

3‧‧‧Protection film

4‧‧‧Polarizing element

5‧‧‧Adhesive layer

6‧‧‧LCD unit

10‧‧‧ Polarizer

11‧‧‧Polaroid

20‧‧‧LCD panel

21‧‧‧Active energy ray hardening type adhesive composition

61‧‧‧Glass

100‧‧‧Optical laminate

FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of the optical laminate of the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of the layer structure of the optical laminate of the present invention.

FIG. 3 is a schematic front view and a schematic cross-sectional view of the laminate manufactured when the evaluation of the generation of bubbles in the examples.

Each member necessary for manufacturing the optical laminate of the present invention will be described. The optical layering system of the present invention has a substrate, an active energy ray-curable adhesive layer, a polarizing plate, and an adhesive layer in this order. Moreover, if necessary, the liquid crystal cell may be laminated on the outside of the adhesive layer.

[Substrate]

The substrate used in the laminate of the present invention is preferably an optically transparent substrate. The so-called optically transparent means that it has 85% transmittance in the wavelength range of 460 to 720nm. The thickness of the substrate is usually 0.5 to 5 mm. In addition, the refractive index of the substrate is preferably close to the refractive index of the active energy ray-curable adhesive layer and the liquid crystal panel, and is preferably 1.4 to 1.7.

The substrate system may be a glass substrate or a resin substrate. Examples of the glass forming the glass substrate include borosilicate acid and soda lime. Specifically, EAGLE XG (registered trademark) (CORNING company), JADE (registered trademark) (CORNING company), etc. are mentioned. Examples of the resin forming the resin substrate include polyester resins such as polyethylene terephthalate, polycarbonate resins, and acrylic resins such as polymethyl methacrylate.

The substrate may be a touch panel. The touch panel can adopt a conventionally known one, and usually includes a conductive layer disposed between two transparent substrates. Examples of the two transparent substrates include the aforementioned glass substrates, and examples of the conductive layer include indium tin oxide.

[Active Energy Ray Hardening Adhesive Layer]

The active energy ray-curable adhesive layer is a layer existing between the substrate and the polarizing plate, and is a layer for filling the air gap between the substrate and the polarizing plate to connect the substrate and the polarizing plate. By filling the air gap with an active energy ray-curable adhesive layer, the impact resistance can be improved, or the light loss due to reflection can be reduced. The active energy ray-curable adhesive layer can be made by irradiating the active energy ray-curable adhesive composition with active energy It is formed by hardening. In the present invention, the active energy ray-curable adhesive layer covers the side peripheral surfaces of the polarizing plate and the adhesive layer. That is, the active energy ray-curable adhesive layer, the side peripheral surface of the polarizing plate, and the side peripheral surface of the adhesive layer contact each other at all positions. When the side peripheral surface of the polarizing plate and the side peripheral surface of the adhesive layer are in contact with the active energy ray-curable adhesive layer at 90% or more, the present invention can achieve a more remarkable effect.

The thickness of the active energy ray-curable adhesive layer is usually 30 to 200 μm, preferably 50 to 200 μm, and preferably 80 to 150 μm. The active energy ray-curable adhesive layer is preferably optically transparent. The so-called optically transparent means that it has 85% transmittance for light from 460 to 720nm. In addition, the refractive index of the active energy ray-curable adhesive layer is preferably close to the refractive index of the substrate and the liquid crystal panel, and is preferably 1.4 to 1.7.

[Active energy ray-curable adhesive composition]

The diffusion coefficient of the polymerizable monomer contained in the active energy ray-curable adhesive composition in the adhesive layer described below is 1.2×10 ⁻⁸ cm ² /s or less. The polymerizable single system contained in the active energy ray hardening type adhesive composition has such a diffusion coefficient, thereby suppressing the penetration of monomers and oligomers into the adhesive layer. The diffusion coefficient is preferably 1.1×10 ^-8 cm ² /s or less, more preferably 0.5×10 ^-8 cm ² /s or less, and even more preferably 0.4×10 ^-8 cm ² /s or less.

In addition, the diffusion coefficient is usually 1.0×10 ^-15 cm ² /s or more. In this specification, the diffusion coefficient refers to a value measured using the method described in Examples described later.

In this specification, the so-called active energy ray hardening type The polymerizable monomer contained in the adhesive composition means that the polymerizable monomer contains a ratio of 10 parts by weight or more per 100 parts by weight of the active energy ray-curable adhesive composition, and it is not considered to contain less than 10 parts by weight The ratio of the diffusion coefficient of the polymerizable monomer. When the content ratio of the polymerizable monomer is less than 10 parts by weight, since the amount of penetration into the adhesive layer is relatively small, bubbles themselves are not easily generated. Therefore, the recognition will not cause the problem of poor recognition.

The active energy ray-curable adhesive composition system is preferably liquid. The active energy ray-curable adhesive composition system usually contains a polymerizable monomer. Examples of the polymerizable monomer include cationic polymerizable compounds and radical polymerizable compounds, and radical polymerizable compounds are preferred. Examples of the cationic polymerizable compound include compounds having at least one oxetane ring (4-membered cyclic ether) in the molecule (hereinafter referred to as oxetane compounds), and at least one in the molecule. Compounds of ethylene oxide ring (3-membered cyclic ether) (hereinafter referred to as epoxy compounds), etc. The radically polymerizable compound is preferably a compound having at least one (meth)acryloyloxy group in the molecule (hereinafter, referred to as (meth)acrylic compound). In addition, in this specification, (meth)acryloyloxy means methacryloyloxy or acryloyloxy, and the same applies to other terms with (meth) added.

Examples of (meth)acrylic compounds include (meth)acrylate monomers having at least one (meth)acryloyloxy group in the molecule, and at least two (meth)acrylic groups in the molecule. Acyloxy (meth)acrylate oligomers, etc. These can be used individually or in combination of two or more. When two or more kinds are used in combination, two or more kinds of (meth)acrylates can be used The monomer may also be two or more (meth)acrylate oligomers, and of course, one or more (meth)acrylate monomers and one or more (meth)acrylate oligomers To use things together.

Examples of the (meth)acrylate monomers described above include monofunctional (meth)acrylate monomers having one (meth)acryloyloxy group in the molecule, and two (meth)acrylate monomers in the molecule. ) A bifunctional (meth)acrylate monomer of acryloxy, and a multifunctional (meth)acrylate monomer having more than three (meth)acryloxy groups in the molecule.

Examples of monofunctional (meth)acrylate monomers include tetrahydrofurfuryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and (meth) ) 3-hydroxypropyl acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, (methyl ) Methyl acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, third butyl (meth) acrylate, ( 2-ethylhexyl methacrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, deca(meth)acrylate Diester, cyclohexyl (meth)acrylate, 1,4-cyclohexane dimethanol monoacrylate, dicyclopentyl (meth)acrylate, dicyclopentenyl (meth)acrylate, (methyl) Benzyl methacrylate, isobornyl (meth)acrylate, phenoxyethyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, methylaminoethyl (meth)acrylate , Ethyl carbitol (meth) acrylate, trimethylolpropane mono (meth) acrylate, neopentaerythritol mono (meth) acrylate, phenoxy polyethylene glycol (meth) acrylic acid Ester etc.

As the monofunctional (meth)acrylate monomer, a carboxyl group-containing (meth)acrylate monomer can also be used. Examples of carboxyl group-containing monofunctional (meth)acrylate esters include 2-(meth)acryloyloxyethyl phthalic acid and 2-(meth)acryloyloxyethyl hexahydrophthalate Dicarboxylic acid, carboxyethyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinic acid, N-(meth)acryloyloxy-N',N'-dicarboxymethyl-p Phenylenediamine, 4-(meth)acryloxyethyl trimellitic acid, etc.

烷-2,5-二基二(甲基)丙烯酸酯[別名：二

烷二醇二(甲基)丙烯酸酯]、羥基三甲基乙醛與三羥甲基丙烷的縮醛化合物[化學名：2-(2-羥基-1,1-二甲基乙基)-5-乙基-5-羥甲基 -1,3-二

烷]的二(甲基)丙烯酸酯、參(羥乙基)三聚異氰酸酯二(甲基)丙烯酸酯等。 Examples of bifunctional (meth)acrylate monomers include ethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, and 1,4-butanediol di( Meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trihydroxy Methylpropane di(meth)acrylate, neopentyl alcohol di(meth)acrylate, bistrimethylolpropane di(meth)acrylate, diethylene glycol di(meth)acrylate, tri Ethylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth) Acrylate, polytetramethylene glycol di(meth)acrylate, polysiloxane di(meth)acrylate, di(meth)acrylate of hydroxytrimethylacetate neopentyl glycol ester, 2,2 -Bis[4-(methyl)acryloyloxyethoxyethoxyphenyl]propane, 2,2-bis[4-(meth)acryloyloxyethoxyethoxycyclohexyl]propane , Hydrogenated dicyclopentadienyl di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, 1,3-di

Alkane-2,5-diyl di(meth)acrylate [alias: di

Alkanediol di(meth)acrylate], acetal compound of hydroxytrimethylacetaldehyde and trimethylolpropane [chemical name: 2-(2-hydroxy-1,1-dimethylethyl)- 5-ethyl-5-hydroxymethyl-1,3-di

Alkane] di(meth)acrylate, ginseng (hydroxyethyl) trimer isocyanate di(meth)acrylate, etc.

Examples of trifunctional or more polyfunctional (meth)acrylate monomers include glycerin tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, and bistrimethylolpropane tri( Methacrylates, ditrimethylolpropane tetra(meth)acrylates, neopentaerythritol tri(meth)acrylates, neopentaerythritol tetra(meth)acrylates, dipentaerythritol tetra (Meth)acrylate, poly(meth)acrylate of trifunctional or higher aliphatic polyhydric alcohol of dipentaerythritol penta(meth)acrylate and dipentaerythritol hexa(meth)acrylate. In addition, poly(meth)acrylates of halogen-substituted polyols with more than 3 functions, tri(meth)acrylates of alkylene oxide adducts of glycerin, and alkylene oxide additions of trimethylolpropane Tri-(meth)acrylate, 1,1,1-ginseng[(meth)acryloyloxyethoxyethoxy]propane, ginseng (hydroxyethyl) tripolyisocyanate tri(methyl) Acrylic esters, etc.

Examples of (meth)acrylate oligomers include urethane (meth)acrylate oligomers, polyester (meth)acrylate oligomers, and epoxy (meth)acrylates. Oligomers, etc.

The so-called urethane (meth)acrylate oligomer refers to a compound having a urethane bond (-NHCOO-) and at least two (meth)acryloyloxy groups in the molecule. Specifically, it can be exemplified by urethanization of a hydroxyl-containing (meth)acrylate monomer having at least one (meth)acryloyloxy group and at least one hydroxyl group in the molecule and a polyisocyanate The product of the reaction; and, the urethane compound containing an isocyanate group at the terminal obtained by the reaction of the polyol and the polyisocyanate has at least at least one in the molecule. The product of the urethanization reaction of a (meth)acryloyloxy group and at least one hydroxyl group (meth)acrylate monomer.

Examples of the hydroxyl group-containing (meth)acrylate monomer used in the urethane reaction include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, ( 2-hydroxybutyl methacrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, glycerol di(meth)acrylate, trimethylolpropane di(meth)acrylate, new Pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, etc.

Examples of the polyisocyanate supplied to the urethane reaction with the hydroxyl group-containing (meth)acrylate monomer include hexamethylene diisocyanate, urethane diisocyanate, and isophorone diisocyanate. , Dicyclohexylmethane diisocyanate, methylenediphenyl diisocyanate, xylylene diisocyanate, diisocyanate obtained by hydrogenation of aromatic isocyanates in these diisocyanates (such as hydrogenated methylenediphenyl diisocyanate , Hydrogenated xylylene diisocyanate, etc.), di- or tri-isocyanate such as triphenylmethane triisocyanate, benzhydryl triisocyanate, and polyisocyanate obtained by polymerizing the above diisocyanate.

In addition, examples of the polyhydric alcohols used when they become an isocyanate group-containing urethane compound by reaction with polyisocyanate include aromatic, aliphatic, and alicyclic polyhydric alcohols, and polyhydric alcohols. Ester polyol, polyether polyol, etc. Examples of aromatic polyols include 1,4-benzenedimethanol, 1,3-benzenedimethanol, 1,2-benzenedimethanol, 4,4'-naphthalene dimethanol, and 3,4'-naphthalene dimethanol. Methanol, etc. Examples of aliphatic and alicyclic polyols include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, and triethylene glycol. Propylene glycol, neopentyl glycol, trimethylolethane, trimethylolpropane, bistrimethylolpropane, neopentaerythritol, dipentaerythritol, dimethylolheptane, dimethylolpropane Acid, dimethylol butyric acid, glycerin, hydrogenated bisphenol A, etc.

The polyester polyol is obtained by the dehydration condensation reaction of the above-mentioned polyols with a polycarboxylic acid or its anhydride. As polycarboxylic acids or their anhydrides, succinic acid, succinic anhydride, adipic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, trimellitic acid, trimellitic anhydride, homobenzene Tetracarboxylic acid, pyromellitic anhydride, phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, hexahydrophthalic acid, hexahydrophthalic anhydride, etc.

Examples of polyether polyols include polyalkylene glycols and polyoxyalkylene-modified polyols obtained by reacting the above-mentioned polyols or dihydroxybenzenes with alkylene oxide.

The so-called polyester (meth)acrylate oligomer is a compound having at least two ester bonds and at least two (meth)acryloyloxy groups in the molecule. Specifically, it can be obtained by the dehydration condensation reaction of (meth)acrylic acid, polyvalent carboxylic acid or its anhydride, and polyhydric alcohol. Examples of the polycarboxylic acid or its anhydride used in the dehydration condensation reaction include succinic acid, succinic anhydride, adipic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, and trimellitic acid Formic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, hexahydrophthalic acid, hexahydrophthalic anhydride, phthalic acid, phthalic anhydride, isophthalic acid , Terephthalic acid, etc. In addition, examples of the polyhydric alcohol used in the dehydration condensation reaction include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, and neopentyl glycol. Diol, Trimethylolethane, trimethylolpropane, bistrimethylolpropane, neopentyl alcohol, dipentaerythritol, dimethylol heptane, dimethylol propionic acid, dimethylol butane Acid, glycerin, hydrogenated bisphenol A, etc.

Epoxy (meth)acrylate oligomers, which have at least two (meth)acryloyl oxy groups in the molecule and can be obtained by the addition reaction of polyglycidyl ether and (meth)acrylic acid . Examples of the polyglycidyl ether used in the addition reaction include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and bis Phenol A diglycidyl ether and so on.

The total amount of the radical polymerizable compound is preferably 20 to 80 parts by weight, and more preferably 30 to 70 parts by weight with respect to 100 parts by weight of the active energy ray-curable adhesive composition.

The active energy ray-curable adhesive composition preferably contains a polymerization initiator. When a radical polymerizable compound is contained as a polymerizable monomer, it is preferable to contain a radical polymerization initiator, and when a cationic polymerizable compound is contained as a polymerizable monomer, it is preferable to contain a cationic polymerization initiator. The cationic polymerization initiator may be any one that can generate a cationic species or a Lewis acid by irradiating the active energy ray to initiate a polymerization reaction with a cationic polymerizable monomer typified by an epoxy compound. The radical polymerization initiator may be any one that can initiate polymerization of a radically polymerizable compound such as a (meth)acrylic compound by irradiation with active energy rays, and a known one can be used. Examples of the radical polymerization initiator include acetophenone, 3-methylacetophenone, benzyl dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2- Methylpropane-1-one, 2-methyl-1-[4-(methylthio)phenyl-2-morpholinylpropane Acetophenone series initiators of 1-one and 2-hydroxy-2-methyl-1-phenylpropane-1-one; such as diphenyl ketone, 4-chlorodiphenyl ketone and 4,4' -Phenyl ketones for diaminodiphenyl ketones; such as benzoin ethers for benzoin propyl ether and benzoin ether; for example, 4-isopropyl thioxanthone Thioxanthone-based initiators; in addition, xanthone, stilbene, camphorquinone, benzaldehyde, anthraquinone and the like can be cited.

The radical polymerization initiator system can be easily obtained from commercially available products, and all are indicated by trade names. For example, "IRGACURE (registered trademark) 184", "IRGACURE (registered trademark) 907" and "DAROCUR (registered trademark)" manufactured by BASF Corporation can be cited. (Registered trademark) 1173", "Lucirin (registered trademark) TPO", etc.

The content of the radical polymerization initiator is usually 0.5 to 20 parts by weight, preferably 1 to 6 parts by weight, relative to 100 parts by weight of the total amount of radical polymerizable compounds such as (meth)acrylic compounds. When the amount of the radical polymerization initiator is small, the curing becomes insufficient, and the adhesion between the active energy ray-curable adhesive layer and the polarizing plate tends to decrease.

The content of the cationic polymerization initiator is usually 0.5 to 20 parts by weight, preferably 1 to 6 parts by weight, with respect to 100 parts by weight of the total amount of cationic polymerizable compounds such as epoxy compounds.

When the amount of the cationic polymerization initiator is small, the curing system becomes insufficient, and the adhesion between the active energy ray-curable adhesive layer and the polarizing plate tends to decrease.

The active energy ray-curable adhesive composition may also contain plasticizers, photosensitizers, leveling agents, antioxidants, stabilizers, flame retardants, viscosity modifiers, foam inhibitors, antistatic agents, and the like.

As mentioned above, the minute bubbles that cause poor visibility are generated by the vaporization of the compound. Therefore, the weight loss rate after placing the active energy ray-curable adhesive composition in an environment of 100°C for 24 hours It is better to use 80% or less, more preferably 50% or less, more preferably 30% or less, and especially 20% or less. Although there is no lower limit, it is usually more than 1%. Even if the weight reduction rate is more than 15%, the present invention can still exert significant effects, and even greater than 20%, it can exert significant effects.

Moreover, even if the polymerizable monomer is a cured active energy ray-curable adhesive layer, the cured product can be decomposed into monomer units by using a heating fluid, supercritical fluid, etc., and liquid chromatography can be used , Gas chromatography, etc. to determine.

[Adhesive layer]

The adhesive layer of the optical laminate of the present invention is a layer for attaching the polarizing plate and the liquid crystal cell. The adhesive layer is mostly attached to the liquid crystal cell in a state of being laminated on the polarizing plate in advance. The thickness of the adhesive layer is preferably 30 μm or less, and more preferably 23 μm or less from the point that the surface area in contact with the active energy ray-curable adhesive composition can be reduced and the penetration amount of the polymerizable monomer can be reduced. In addition, from the point of having good adhesion to the polarizing plate and the liquid crystal cell, the thickness of the adhesive layer is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more.

In the present invention, the diffusion coefficient of the polymerizable monomer contained in the active energy ray-curable adhesive composition is 1.2×10 ^-8 cm ² /s or less. In order to adjust the diffusion coefficient in this way, it is not only necessary to adjust the type and content of the polymerizable monomer of the active energy ray-curable adhesive composition, but also to appropriately adjust the characteristics of the adhesive layer. For example, it is better to increase the polarity of the adhesive layer, and the polarity can be improved by copolymerizing polar monomers.

The adhesive layer system can be formed of an adhesive composition, and can be made of resins such as (meth)acrylic system, rubber system, urethane system, ester system, polysiloxane system, and polyvinyl ether system. It is composed of the adhesive composition as the main component. Among them, a (meth)acrylic resin having excellent transparency, weather resistance, heat resistance, etc. is preferably used as the adhesive composition of the matrix polymer. The adhesive composition system may be active energy ray hardening type or thermosetting type.

The acrylic resin used in forming the adhesive layer is preferably made of butyl (meth)acrylate, ethyl (meth)acrylate, methyl (meth)acrylate, isooctyl (meth)acrylate, (A Base) a matrix polymer composed of (meth)acrylate polymers such as 2-ethylhexyl acrylate, or a copolymerized matrix polymer obtained by using two or more kinds of these (meth)acrylates . Furthermore, among these matrix polymers, polar monomers are preferably copolymerized. Examples of polar monomers include (meth)acrylic acid, (meth)acrylic acid 2-hydroxypropyl, (meth)acrylic acid 2-hydroxyethyl, (meth)acrylamide, 2-(N,N -Dimethylamino) ethyl (meth)acrylate, glycidyl (meth)acrylate monomers with polar functional groups such as carboxyl, hydroxyl, amide, amine, epoxy, etc. In particular, when a touch panel function is provided on a glass substrate, or when an ITO film is formed to provide an antistatic function, it is preferable to adjust the content of the hydroxyl group-containing acrylic monomer constituting the matrix polymer, It is set to a composition that has reduced the content of carboxyl groups.

These acrylic resins can be used alone as an adhesive composition, but usually a crosslinking agent is blended in the adhesive composition. As the cross-linking agent, there can be exemplified: an isocyanate compound having at least 2 isocyanate groups (-NCO) in the molecule and forming an urethane bond with a carboxyl group or a hydroxyl group; a divalent or polyvalent epoxy compound , And form ester bond with carboxyl group; divalent or multivalent metal ion, and form metal salt with carboxyl group and hydroxyl group, etc. Among them, the isocyanate compound system is widely used as an organic crosslinking agent.

Examples of the crosslinking agent composed of an isocyanate compound include methylenediphenyl diisocyanate, 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, and methyl ester Xylylene diisocyanate, 1,5-naphthalene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated methylenediphenyl diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, tetramethyl diisocyanate Xylene dimethyl diisocyanate, trimethylol propane methylidene diisocyanate adduct, etc. In addition, the block isocyanate compound formed by condensation reaction of isocyanate groups in these compounds can also be used as a crosslinking agent.

In addition, it is effective to formulate a silane coupling agent in the adhesive composition. The silane coupling agent may be a hydrolyzable group such as an alkoxy group bonded to a silicon atom, and the bond may have a group such as an amine group, an epoxy group, a (meth)acryloyl group, a vinyl group, a halogen group, or a hydrogenthio group A compound made of organic groups of reactive functional groups. Specific examples thereof include vinyl trimethoxysilane, vinyl triethoxysilane, vinyl ginseng (2-methoxyethoxy) silane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-amine 3-propyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-shrink Glyceryloxypropylmethyldimethoxysilane, 3-glycidoxypropylethoxydimethylsilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3- Chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-hydrothiopropyltrimethoxysilane, etc. Furthermore, an oligomer type silane coupling agent can also be formulated. In the case of oligomer type, it may be a condensate of two or more types of monomers.

The adhesive composition may also contain a polymerization initiator, a sensitizer, fine particles for imparting light scattering, beads (resin beads, glass beads, etc.), glass fibers, antistatic agents, fillers (metal powder , Other inorganic powders, etc.), antioxidants, ultraviolet absorbers, dyes, pigments, colorants, defoamers, corrosion inhibitors, photopolymerization initiators and other additives.

[Polarizer]

The polarizing plate has a polarizing element and a protective film. The protective film may be disposed on at least one side of the polarizing element, or may be disposed on both sides of the polarizing element. When the protective film is disposed on both sides of the polarizing element, the protective film may be formed of the same resin as each other, or may be formed of different resins. The protective film is preferably laminated on the polarizing element.

[Polarizing element]

The polarizing element is preferably an optical film having the following properties: it can absorb linearly polarized light having a vibration surface parallel to the optical axis, and penetrate the linearly polarized light having a vibration surface orthogonal to the optical axis; specifically, A polarizing element in which a dichroic dye (iodine or a dichroic organic dye) is adsorbed and aligned on a polyvinyl alcohol-based resin film can be cited.

The thickness of the polarizing element is usually 3 μm or more and 30 μm or less. From the viewpoint of thinning, it is preferably 25 μm or less, and more preferably 15 μm or less. In addition, when a dichroic dye is applied to the polyvinyl alcohol-based resin layer through adsorption alignment as a polarizing element, a polyvinyl alcohol-based resin monomer may be stretched and subjected to dyeing and/or crosslinking, or A solution in which a solution of a polyvinyl alcohol-based resin is applied to a substrate or the like and dried, and then stretched together with the substrate, dyed and cross-linked, and the substrate is removed.

Examples of the base material include polyethylene terephthalate film, polycarbonate film, cellulose triacetate film, norbornene film, polypropylene film, polyester film, and polystyrene film.

As the polyvinyl alcohol-based resin constituting the polyvinyl alcohol-based resin layer, a saponified polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers that can be copolymerized therewith. Examples of other monomers capable of copolymerizing with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and propylene amides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin is usually 80 mol% or more, preferably 95 to 99.99 mol%. When the degree of saponification is less than 80 mol%, The water resistance and moisture and heat resistance of the obtained polarizing plate will decrease. When the degree of saponification is greater than 99.99 mol%, the dyeing speed may be slowed, productivity may be reduced, and a polarizing element having sufficient polarizing performance may not be obtained.

The polyvinyl alcohol-based resin may also be a part of modified modified polyvinyl alcohol. For example, it can be used: olefin modification by ethylene and propylene; unsaturated carboxylic acid by acrylic acid, methacrylic acid, crotonic acid, etc. Modified; modified by alkyl ester of unsaturated carboxylic acid, acrylamide, etc. The modification ratio of the polyvinyl alcohol-based resin is preferably less than 30 mol%, and more preferably less than 10%. When the modification is greater than 30 mol%, the dichroic pigment tends not to be easily adsorbed, and sometimes a polarizing element with sufficient polarizing performance cannot be obtained.

The average degree of polymerization of the polyvinyl alcohol-based resin is preferably about 100 to 10,000, more preferably 1500 to 8000, and still more preferably 2000 to 5000.

When the average degree of polymerization is less than 100, it is difficult to obtain better polarizing performance, and when the average degree of polymerization is more than 10,000, the solubility to the solvent is deteriorated, and the tendency to form a polyvinyl alcohol-based resin layer is difficult.

As the polyvinyl alcohol-based resin, an appropriate commercially available product can be used. Suitable commercial products are all indicated by trade name, and examples include "PVA124" and "PVA117" (both saponification degree: 98 to 99 mol%) manufactured by KURARAY Co., Ltd. and "PVA624" (saponification degree: 95 to 96 mol%), "PVA617" (saponification degree: 94.5 to 95.5 mol%); "N-300" and "NH-18" manufactured by Japan Synthetic Chemical Industry Co., Ltd. (both saponification degree: 98 To 99 mol%), "AH-22" (saponification degree: 97.5 to 98.5 mol) %), "AH-26" (saponification degree: 97 to 98.8 mole %); "JC-33" (saponification degree: 99 mole% or more) manufactured by Japan VAM & POVAL Co., Ltd., "JF-17" , "JF-17L" and "JF-20" (both saponification degree: 98 to 99 mol%), "JM-26" (saponification degree: 95.5 to 97.5 mol%), "JM-33" (saponification Degree: 93.5 to 95.5 mol%), "JP-45" (saponification degree: 86.5 to 89.5 mol%), etc.

The dichroic dye contained (adsorption alignment) in the polarizing element may include iodine or a dichroic organic dye. Examples of dichroic organic dyes include RED BR, RED LR, RED R, PINK LB, RUPIN BL, BORDEAUX GS, SKY BLUE LG, LEMON YELLOW, BULE BR, BLUE 2R, NAVY RY, GREEN LG, VIOLET LB, VIOLET B, BLACK H, BLACK B, BLACK GSP, YELLOW 3G, YELLOW R, ORANGE LR, ORANGE 3R, SCARLET GL, SCARLET KGL, CONGO RED, BRILLIANT VIOLET BK, SUPRA BLUE G, SUPRA BLUE GL, SUPRA ORANGE GL, DIRECT SKY BLUE, DIRECT FAST ORANGE S, FAST BLACK. The dichroic pigment system may be used alone or in combination of two or more.

[Protection film]

As the protective film, cellulose acetate resin, chain olefin resin, cyclic olefin resin, acrylic resin, polyimide resin, polycarbonate resin, polyester resin, etc. can be used in the present invention. Thermoplastics formed from materials widely used as protective film forming materials in the past Resin film. When the polarizing element has protective films on both sides, the two protective films may be protective films formed of the same resin, or may be protective films formed of different resins.

Examples of cellulose acetate resins include cellulose triacetate and cellulose diacetate, which are resins that are part or complete of cellulose acetate.

As the cellulose acetate resin film, a commercially available product can be used. Examples of suitable commercially available products include "FUJITAC (registered trademark) TD80", "FUJITAC (registered trademark) TD80UF", "FUJITAC (registered trademark) TD80UZ" sold by Fujifilm Co., Ltd., and Konica Minolta Co., Ltd. "KC8UX2M" and "KC8UY" (above, all indicated by trade names) etc. sold by the company.

The chain olefin-based resin is a polymer having a chain olefin such as ethylene or propylene as a main monomer, and may be a homopolymer or a copolymer. Among them, a homopolymer of propylene or a copolymer of propylene copolymerized with a small amount of ethylene is preferred.

Examples of monomers that constitute cyclic olefin-based resins include camphene. If an example of a substitute for norbornene is given, the double bond position of norbornene is regarded as the 1,2-position, and there are 3-substituted, 4-substituted, 4,5-disubstituted, etc., and the Cyclopentadiene, dimethanooctahydronaphthalene (dimethano octahydronaphthalene), etc. can also be used as monomers constituting the cyclic olefin resin.

As a cyclic olefin resin obtained by polymerizing norbornene monomers, it is sold by ZEON Corporation of Japan "ZEONEX (registered trademark)" and "ZEONOR (registered trademark)", "ARTON (registered trademark)", etc. sold by JSR Corporation. Commercially available products of these cyclic olefin resin films and stretched films are also available. As a commercially available product, there are "ZEONOR film (registered trademark)" sold by Japan Zeon Co., Ltd., and "ARTON (registered trademark) film" sold by JSR Co., Ltd., by Sekisui Chemical Industry Co., Ltd. "Esushina (registered trademark) retardation film" sold by the company.

Acrylic resin is a polymer with methyl methacrylate as the main monomer. It can be a homopolymer of methyl methacrylate or a copolymer of methyl methacrylate and acrylate such as methyl acrylate .

The polyimide resin is a polymer having an amide imide bond in the main chain. Examples of the polymer include tetracarboxylic dianhydride and diamine to form a precursor of polyimide. Dehydration/cyclization (acid imidization) reaction.

The polycarbonate-based resin is a polymer having a carbonate bond in the main chain, and may be obtained by condensation polymerization of bisphenol A and phosgene.

The polyester resin is a polymer obtained by condensation polymerization of a dibasic acid and a diol, and polyethylene terephthalate and the like can be mentioned.

In addition, the surface of the protective film farther away from the polarizing element may be subjected to surface treatments such as anti-glare treatment, hard coating treatment, antistatic treatment, and anti-reflection treatment, and may also be formed of liquid crystal compounds, other high molecular weight compounds, etc. The formed coating layer.

When the thickness of the protective film is too thin, the strength will be reduced The workability tends to be poor, and when it is too thick, the transparency tends to decrease, or the weight of the polarizing plate tends to increase. The thickness of the protective film in the polarizing plate of the present invention is usually 5 to 100 μm, preferably 10 to 80 μm, and more preferably 50 μm or less.

[Adhesive]

When the protective film and the polarizing element are laminated and laminated, an adhesive can be used for laminating the protective film and the polarizing element. Examples of the adhesive include active energy ray-curable adhesive compositions and water-based adhesives.

The active energy ray-curable adhesive composition may be the same as or different from the active energy ray-curable adhesive composition disposed between the substrate and the polarizing plate.

Examples of the water-based adhesive include those containing a polyvinyl alcohol-based resin and a urethane resin as the main component.

The thickness of the adhesive layer obtained after drying or curing is usually 0.01 to 5 μm, but when an aqueous adhesive is used, it can be set to 1 μm or less. On the other hand, when an active energy ray-curable adhesive is used, it is preferably 2 μm or less, and more preferably 1 μm or less. If the adhesive layer is too thin, there is a fear of insufficient adhesion. If the adhesive layer is too thick, the polarizing plate may have a poor appearance.

[Manufacturing method of optical laminate]

The optical layered body of the present invention can be formed by coating an active energy ray-curable adhesive composition on a polarizing plate and/or a substrate, bonding the polarizing plate to the substrate, and forming an active energy ray-curing adhesive composition Hardened Made. At this time, the polarizing plate may be laminated on the liquid crystal cell through the adhesive layer if necessary.

The shape of the optical layered body of the present invention is not particularly limited, but it is preferably rectangular. By setting the shape of the laminate to be rectangular, it is easy to arrange the active energy ray-curable adhesive composition, and a liquid crystal display device having more excellent visibility can be obtained. When assembling a general optical layered body into a small liquid crystal display device such as a mobile phone or tablet terminal device, it is clearly understood that, compared to a large liquid crystal display device such as a TV, it is The area and the end area are relatively large, so when bubbles are generated at the end of the polarizing plate, the user is more likely to feel the portion where the visibility is reduced. In the optical layered body of the present invention, since bubbles are not generated at the end of the polarizing plate, it is also suitable for assembling in a small liquid crystal display device. From the viewpoint of the ease of feeling bubbles, when the shape of the optical layered body is rectangular, the size of the optical layered body assembled in the liquid crystal display device, the length of its long side is preferably 5 cm or more, or 10 cm or more, Usually below 30cm. In addition, the length of the short side is preferably 3 cm or more, or 5 cm or more, and usually 20 cm or less. In addition, the term “end portion” refers to an area up to 5 mm from the edge of the adhesive layer.

As a method of applying the active energy ray-curable adhesive composition to the polarizing plate and/or the substrate, known methods such as die-slot coating, blade coating, and curtain coating can be used.

The active energy ray-curable adhesive composition can be applied to the entire surface of the main surface of the polarizing plate and/or substrate, or it can be applied so that an uncoated portion remains on a part of the main surface of the polarizing plate and/or substrate.

After applying the active energy ray-curable adhesive to the polarizing plate and/or the substrate, the polarizing plate and the substrate are bonded together to obtain a laminate. At this time, in order to adjust the thickness of the active energy ray-curable adhesive layer, a support rod, a spacer, or the like may be used to maintain the distance between the polarizing plate and the substrate.

By irradiating the active energy ray to the patch, the active energy ray hardening type adhesive composition can be hardened to become an active energy ray hardening type adhesive layer, and the optical laminate of the present invention can be obtained.

Examples of the active energy rays irradiated to the active energy ray-curable adhesive composition include visible rays, ultraviolet rays, X-rays, and electron beams, and ultraviolet rays are particularly preferred. Examples of light sources for active energy rays include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, carbon arc lamps, tungsten lamps, gallium lamps, excimer lasers, and emission wavelengths ranging from 380 to 440 nm LED light source, chemical lamp, black light lamp, microwave excited mercury lamp, metal halide lamp.

The intensity of the active energy ray irradiated to the active energy ray-curable adhesive composition is usually 0.1 to 100 mW/cm ² . When the active energy ray-curable adhesive composition contains a polymerization initiator, it is preferable to set the intensity of the active energy ray in the wavelength region effective for activation of the polymerization initiator to 0.1 to 100 mW/cm ² . When the intensity of the active energy ray is within the above range, the reaction time can be shortened, and at the same time, the yellowing of the active energy ray-curable adhesive layer due to radiant heat or the reaction heat can be suppressed and the protection film can be deteriorated.

The cumulative light quantity expressed as the product of the intensity of the active energy ray and the irradiation time is preferably 10 to 5000 mJ/cm ² . When the cumulative light amount is within the above range, a sufficient amount of active species of the polymerization initiator can be generated, while the irradiation time of the active energy ray can be shortened and productivity can be improved.

The layer structure of the optical laminate of the present invention manufactured in this way will be described. The schematic diagram shown in FIG. 1 shows a cross section of an optical laminate 100 in which a polarizing plate 10 having a protective film 3 on both sides of a polarizer 4 and a substrate 1 are laminated through an active energy ray-curable adhesive layer 2. Then, the polarizing plate 10 and the liquid crystal cell 6 are laminated through the adhesive layer 5. In FIG. 1, the side peripheral surface of the polarizing plate 10 and the side peripheral surface of the adhesive layer 5 are covered with the active energy ray-curable adhesive layer 2.

In the liquid crystal cell, the surface opposite to the surface to which the polarizing plate 10 is bonded is the opposite side, and the polarizing plate 11 is usually laminated. For this polarizing plate system, a conventionally known polarizing plate can be applied. FIG. 2 is an optical laminate in which the liquid crystal panel 20 and the substrate 1 are laminated through the active energy ray-curable adhesive layer 2. The liquid crystal panel 20 has a structure in which a polarizing plate having a protective film 3 on both sides of the polarizing element 4, an adhesive layer 5, a liquid crystal cell 6, and a known polarizing plate 11 are laminated in order. Moreover, a liquid crystal display device can be obtained by combining with a backlight unit or the like.

Since the optical layered body of the present invention can suppress bubbles generated by the penetration and vaporization of the polymerizable monomer contained in the active energy ray-curable adhesive composition, it has excellent visibility and can be suitably assembled in various LCD device.

(Example)

Hereinafter, the present invention will be described with examples, but the present invention is not limited to these examples at all.

<Active energy ray-curable adhesive composition>

Composition A: Using 100 parts by weight of composition A, containing 30 parts by weight or more of isobornyl acrylate as an acrylic monomer component, and using an active energy ray hardening type adhesive containing "IRGACURE (registered trademark) 184" Agent composition, as a radical polymerization initiator. At an air flow rate of 100 mml/min, the temperature was increased from 30°C to 5°C/min to 100°C, and the weight after maintaining at 100°C for 24 hours was compared to the weight at 30°C (before temperature increase) Weight) is a 24% reduction. That is, the weight reduction rate of the active energy ray-curable composition A after being left in an environment of 100° C. for 24 hours is 24%. The gas generated during the period of maintaining at 100° C. for 24 hours was recovered and analyzed, and as a result, a component derived from isobornyl acrylate was detected.

Composition B: It uses dicyclopentenyloxyethyl methacrylate containing 20 parts by weight or more based on 100 parts by weight of composition B. As an acrylic monomer component, it contains "IRGACURE (registered trademark) 184" "The active energy ray hardening type adhesive composition is used as a radical polymerization initiator. The weight reduction rate was measured in the same manner as the composition A. As a result, the weight reduction rate of the active energy ray-curable composition B after being left in an environment of 100° C. for 24 hours was 13%. The gas generated within a period of maintaining at 100° C. for 24 hours was recovered and analyzed, and as a result, a component derived from dicyclopentenyloxyethyl methacrylate was detected.

<adhesive layer> <Production Example 1: Production of (meth)acrylic resin (A-1) for adhesive layer>

In a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer, and a stirrer, a solution obtained by mixing monomers having a composition shown in Table 1 (values in Table 1 are parts by weight) and 81.8 parts of ethyl acetate was added. After replacing the air in the reaction vessel with nitrogen, the internal temperature was set to 60°C. Subsequently, a solution prepared by dissolving 0.12 parts of azobisisobutyronitrile in 10 parts of ethyl acetate was added. After maintaining at the same temperature for 1 hour, and keeping the internal temperature at 54 to 56°C, ethyl acetate was continuously added to the reaction vessel at an addition rate of 17.3 parts/Hr so that the polymer concentration became approximately 35%. Inside. Within 12 hours from the start of the addition of ethyl acetate, after maintaining the internal temperature at 54 to 56°C, ethyl acetate was added to adjust the concentration of the polymer to 20% to obtain a (meth)acrylic system An ethyl acetate solution of resin (A-1). The weight average molecular weight Mw of the (meth)acrylic resin (A-1) was 1.39 million, and the ratio Mw/Mn of the weight average molecular weight Mw to the number average molecular weight Mn was 5.32.

<Production Example 2: Production of (meth)acrylic resin (A-2) for adhesive layer>

Except having set the composition of the monomer as shown in Table 1, it carried out similarly to the manufacturing example 1, and obtained the ethyl acetate solution (resin concentration: 20%) of (meth)acrylic-type resin (A-2). . The weight average molecular weight Mw of (meth)acrylic resin (A-2) was 1.41 million, and Mw/Mn was 4.71.

<Production Example 3: Production of (meth)acrylic resin (A-3) for adhesive layer>

Except having set the composition of the monomer as shown in Table 1, it carried out similarly to the manufacturing example 1, and obtained (meth)acrylic resin (A-3) Ethyl acetate solution (resin concentration: 20%). The weight average molecular weight Mw of (meth)acrylic resin (A-3) was 1.38 million, and Mw/Mn was 5.11.

In the above production example, the weight average molecular weight Mw and the number average molecular weight Mn are based on four "TSKgel XL" manufactured by TOSOH Corporation and one "Shodex (registered trademark) GPC KF-802 manufactured by Showa Denko Co., Ltd." ”A total of 5 are arranged in series in the GPC device as a column, using tetrahydrofuran as the eluent, under the conditions of sample concentration 5 mg/mL, sample introduction volume 100 μL, temperature 40° C., flow rate 1 mL/min. It is measured by standard polystyrene conversion. The conditions for obtaining the discharge curve of GPC are also the same.

The composition of the monomers in each production example (the numerical values in Table 1 are parts by weight) are summarized in Table 1.

The abbreviation in the "Monomer Composition" column of Table 1 means the following monomers.

BA: butyl acrylate, MA: methyl acrylate, HEA: 2-hydroxyethyl acrylate, AA: acrylic

(1) Preparation of adhesive composition

In the ethyl acetate solution (resin concentration: 20%) of the (meth)acrylic resin obtained in the above manufacturing example, the silane compound (B) and the ionic compound (C ), and the isocyanate-based crosslinking agent (D) are mixed in the amounts (parts by weight) shown in Table 2, and ethyl acetate is added so that the solid content concentration becomes 14% to obtain an adhesive composition. The formulation amount of each formulation component shown in Table 2 represents the parts by weight as the active ingredient contained when the product used contains a solvent or the like.

The detailed contents of each compounding ingredient shown in Table 2 as abbreviations are as follows.

(Silane compound)

B-1: 3-glycidoxypropyltrimethoxysilane

(Ionic compound)

C-1: N-octylpyridinium hexafluorophosphate.

(Isocyanate-based crosslinking agent)

D-1: Ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (solid content concentration 75%), trade name "CORONATE (registered trademark) L" obtained from TOSOH Corporation.

(2) Manufacture of adhesive layer

Each adhesive composition prepared in the above (1) was coated on a polyethylene terephthalate film that had been subjected to release treatment using a coater so that the thickness after drying became 20 μm. The release surface of the insulating film [trade name "PLR-382051" obtained from LINTEC Corporation]. Each of the coated adhesive compositions was dried at 100° C. for 1 minute to produce adhesive sheets each having adhesive layers A, B, and C.

<Measurement of Diffusion Coefficient>

The diffusion coefficient is determined by the infrared ATR (Attenuated Total Reflection) method using diamonds as the prisms in the following manner. First, attach an adhesive layer with a thickness of 20 μm to the diamond. Regarding all adhesive layers, both the adhesive layer and the diamond are kept tight by the adhesiveness of the adhesive layer itself. Subsequently, the composition was dropped onto the adhesive layer, and infrared ATR measurement was started. The penetration depth of light is about 2 μm.

After 12 minutes from the start of the measurement, the absorbance of 810 cm ^-1 of the carbon-carbon double bond derived from the acryl group possessed by the polymerizable monomer was measured. The vertical axis is set to ln(1-A _t /A _∞ ), and the horizontal axis is set to time t, the above measurement results are plotted, and fitting is performed by a linear function. The fitting result is compared with the following formula to calculate the diffusion coefficient D. In addition, A _t after 12 minutes from the start of measurement is regarded as A∞.

<Example 1>

First, by dry stretching, a polyvinyl alcohol resin film with a thickness of 75 μm (average degree of polymerization of about 2,400, saponification degree of 99.9 mol% or more) was uniaxially stretched to about 5 times, and then kept in a stretched state at 60 After immersing in pure water at 1° C. for 1 minute, it was immersed in an aqueous solution having a weight ratio of iodine/potassium iodide/water of 0.05/5/100 at 28° C. for 60 seconds. Subsequently, it was immersed in an aqueous solution having a weight ratio of potassium iodide/boric acid/water of 8.5/8.5/100 at 72°C for 300 seconds.

Next, after washing with pure water at 26°C for 20 seconds, it was dried at 65°C to obtain a polarizing element having a thickness of 28 μm with iodine adsorbed on the polyvinyl alcohol film.

Dissolve 3 parts of carboxy-modified polyvinyl alcohol [trade name "KL-318" obtained from KURARAY Co., Ltd.] in 100 parts of water, and then add 1.5 parts of polyamido ring which is a water-soluble epoxy resin to this aqueous solution Oxygen-based additives [trade name "Sumirez Resin (registered trademark) 650(30)", an aqueous solution with a solid content concentration of 30% obtained from Tiangang Chemical Industry Co., Ltd.] were used to obtain an epoxy-based adhesive, which was then bonded The agent is coated on one side of the polarizing element, and a cellulose triacetate film [trade name "Konica Minolta TAC film" manufactured by Konica Minolta Co., Ltd.] with a thickness of 25 μm as a transparent protective film is attached. Among the above polarizers, there are three The surface of the cellulose acetate film is the surface on the opposite side, and the unstretched film composed of norbornene-based resin and having a thickness of 23 μm is bonded through the aforementioned adhesive [trade name "ZEONOR (registered trademark made by Japan Zeon Co., Ltd. )"].

The unstretched film composed of the aforementioned norbornene-based resin was passed through the adhesive layer A and the adhesive sheet was bonded using a bonding machine, and cured at a temperature of 23°C and a relative humidity of 65% for 7 days to obtain Polarizer with adhesive.

As shown in FIG. 3, the manufactured polarizer with an adhesive is bonded to the glass 61 through the adhesive layer A (adhesive layer 5), and the composition A and the polarizing plate 10 and the adhesive layer A ( The ends of the adhesive layer 5) are in contact. Subsequently, the composition A is irradiated with ultraviolet rays (ultraviolet irradiation amount: 10000 mJ/cm ² or more in the UVA region) to manufacture the adhesive layer A (adhesive layer 5) and the active energy ray-curable adhesive layer 21 in contact Layered body. FIG. 3(a) shows a front view of the laminate, and FIG. 3(b) shows a cross-sectional view of the laminate.

The aforementioned laminate was placed in an environment of 85°C for 500 hours or an environment of 100°C for 100 hours, and a heat resistance test was performed. The layered body that has been left for a predetermined period of time is confirmed by the 10x magnification lens to see whiteness (air bubbles) at the end of the polarizing plate. When bubbles are confirmed, the distance from the end of the polarizing plate to the part where bubbles cannot be confirmed is measured. The results are shown in Table 1. Regarding the judgment, when all the heat resistance tests of 500 hours under the environment of 85°C and 100 hours under the environment of 100°C have confirmed bubbles, it is judged as ×, and only one of them is confirmed by the heat resistance test. Judge when bubbles It was determined to be ○, and it was determined to be ◎ when bubbles were not confirmed in all heat resistance tests.

In addition, when it was left for 100 hours in an environment of 100° C. and the bubbles generated during the heat resistance test were analyzed, a component derived from isobornyl acrylate was detected. The results are shown in Table 3.

<Example 2>

Except that the adhesive layer A was changed to the adhesive layer B, the polarizing plate and the laminate were manufactured in the same manner as in Example 1, and the heat resistance test was performed in the same manner as in Example 1. The results are shown in Table 3.

<Comparative Example 1>

Except that the adhesive layer A was changed to the adhesive layer C, the polarizing plate and the laminate were manufactured in the same manner as in Example 1, and the heat resistance test was performed in the same manner as in Example 1. As a result, it was confirmed that bubbles were generated at the end of the polarizer. When analyzing air bubbles, the components derived from isobornyl acrylate were detected from all air bubbles generated in the heat resistance test. The results are shown in Table 3.

<Example 3>

Except that the composition A was changed to the composition B, the polarizing plate and the laminate were manufactured in the same manner as in Comparative Example 1, and the heat resistance test was performed in the same manner as in Example 1. The results are shown in Table 3.

<Example 4>

In addition to changing composition A to composition B, the rest In Example 1, a polarizing plate and a laminate were produced in the same manner, and the heat resistance test was performed in the same manner as in Example 1. The results are shown in Table 3.

<Example 5>

Except that the composition A was changed to the composition B, the polarizing plate and the laminate were manufactured in the same manner as in Example 2, and the heat resistance test was performed in the same manner as in Example 1. The results are shown in Table 3.

(Possibility of industrial use)

According to the present invention, it is possible to provide an optical layered body and a display device that do not easily generate bubbles at the end of the adhesive layer under a high-temperature environment and have excellent visibility. Therefore, they are useful.

1‧‧‧ substrate

2‧‧‧ Active energy ray hardening adhesive layer

3‧‧‧Protection film

4‧‧‧Polarizing element

5‧‧‧Adhesive layer

6‧‧‧LCD unit

10‧‧‧ Polarizer

20‧‧‧LCD panel

100‧‧‧Optical laminate

Claims (5)

An optical laminate comprising: a substrate, an adhesive layer, a polarizing plate, and an adhesive layer in sequence, wherein the adhesive layer covers the side peripheral surfaces of the polarizing plate and the adhesive layer, and the adhesive layer contains The active energy ray-curable adhesive composition of the polymerizable monomer is formed, and the diffusion coefficient of the polymerizable monomer in the adhesive layer is 1.2×10 ^-8 cm ² /s or less. The optical laminate as described in item 1 of the patent application, wherein the weight reduction rate of the active energy ray-curable adhesive composition after being left in an environment of 100° C. for 24 hours is 50% or less. The optical laminate according to item 1 or 2 of the patent application range, wherein the diffusion coefficient of the polymerizable monomer in the adhesive layer is 0.5×10 ^-8 cm ² /s to 1.1×10 ^-8 cm ² / s. The optical laminate according to item 1 or 2 of the patent application range, wherein the diffusion coefficient of the polymerizable monomer in the adhesive layer is 0.29×10 ^-8 cm ² /s or less. A liquid crystal display device is provided with the optical laminate as described in any one of the items 1 to 4 of the patent application.

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