KR101453406B1 - Light diffusion adhesive composition, polarizing plate and liquid crystal display device using the composition - Google Patents

Abstract

The present invention relates to a light-diffusing pressure-sensitive adhesive composition, a polarizing plate using the same, and a liquid crystal display device, and more particularly to an acrylic pressure-sensitive adhesive resin, a crosslinking agent and a light-diffusing agent, which comprises a crosslinking agent and a hydrophobic alkoxysilane compound By including the modified inorganic particles, the dispersibility and storage stability of the pressure-sensitive adhesive composition are excellent, and the processability can be improved. When applied to a polarizing plate, the moire phenomenon caused by the prism sheet can be suppressed. And a polarizing plate and a liquid crystal display using the same. 2. Description of the Related Art

Light diffusion adhesive, storage stability, polarization degree, moire

Description

TECHNICAL FIELD [0001] The present invention relates to a light diffusion pressure-sensitive adhesive composition, a polarizing plate using the same, and a liquid crystal display device using the same. BACKGROUND ART [0002] Liquid diffusing adhesive compositions,

The present invention relates to a light-diffusing pressure-sensitive adhesive composition which is excellent in dispersibility and storage stability and can improve workability, a polarizing plate using the same, and a liquid crystal display device.

In general, a liquid crystal display device (LCD) includes a liquid crystal panel including a liquid crystal cell including a liquid crystal, a polarizing plate stacked on both sides of the liquid crystal cell, and a backlight unit for providing light to the liquid crystal panel .

The backlight unit is composed of a reflection plate, a backlight light source, a light guide plate, a light diffusion member (diffusion plate, diffusion sheet), a prism sheet and the like in order to make the light of the light source uniform and improve the utilization efficiency of brightness and light, Wedge, edge or direct light depending on the manner in which they are arranged.

1, the edge type backlight unit 10 includes a light source 11, a reflective sheet 12, a light guide plate 13, a diffusion sheet 14, A sheet 15, and a protective sheet 16. As the light source 11, a cold cathode fluorescent lamp (CCFL) or an external electrode fluorescent lamp (EEFL) capable of generating light of a predetermined wavelength is used. The light guide plate 3 uniformizes the light incident through the light incident surface disposed on the side surface and emits light toward the liquid crystal panel disposed on the upper side through the light exit surface, The light emitted from the light guide plate 13 is reflected to the light guide plate 13 to improve the light efficiency. The light emitted from the light output surface of the light guide plate 13 is incident on the diffusion sheet 14, and the diffusion sheet 14 spreads or condenses the incident light to uniform the brightness and widen the viewing angle. On the other hand, the brightness of the light passing through the diffusion sheet 14 drops sharply. To compensate for this, one or two prism sheets 15 are used. The prism sheet 15 refracts the light emitted from the diffusion sheet 14 and concentrates the light incident at a low angle toward the front side, thereby raising the luminance in the effective viewing angle range. The protective sheet 16 functions to prevent scratches on the prism sheet 15 and re-magnify the viewing angle reduced by the prism sheet 15 within a predetermined range.

2, the direct-type backlight unit 20 includes a light source 21, a reflection sheet 22, a diffusion plate 27, a diffusion sheet 24, A prism sheet 25, a protective sheet 26, and a lower chassis 23. [ The diffuser plate 27 allows the light generated from the light source 21 to be directed toward the liquid crystal panel and incident at a wide angle and the lower chassis 23 accommodates the plurality of light sources 21 and the reflective sheet 22 And the constituent parts except for these are the same as those described in the edge type backlight unit.

Among the parts constituting such a backlight unit, the prism sheet is used to improve the brightness by refracting and condensing light passing through the diffusion sheet or the diffusion plate. However, the light passing through the prism sheet is reflected by interference between the ridgeline and the curve of the prism sheet Moire phenomenon as a phenomenon occurs, which causes deterioration of display quality such as visibility of the liquid crystal display device. Therefore, it has been required to develop a liquid crystal display device free from such a problem.

In order to solve this problem, a method using a prismatic film having a serpentine shape (Korean Patent Laid-Open Publication No. 2007-0084410), a backlight unit further comprising a protective layer made of diffusion particles and a resin- (Korean Published Patent Application No. 2007-0109134). According to this method, although the moire phenomenon is suppressed to a certain extent, the manufacturing process is not complicated or economical, and the thickness of the backlight unit also increases, so that it is difficult to meet the thinness required in recent years for liquid crystal display devices.

As another method for suppressing the moire phenomenon and responding to the thinness of the liquid crystal display device, there has been proposed a method using a diffusion adhesive. First, when inorganic particles are used as a light diffusing agent, miscibility with the pressure-sensitive adhesive resin is deteriorated and the particles are aggregated with each other to cause precipitation. Korean Unexamined Patent Application Publication No. 1999-0028342 (published on Apr. 15, 1999) discloses a method for improving the moire phenomenon caused by a prism sheet by adding organic particles having different refractive indexes to a pressure-sensitive adhesive, Lt; / RTI > However, when organic particles are added to the acrylic pressure-sensitive adhesive, the swelling of the organic particles causes a change in the viscosity of the organic particles. As a result, the storage stability of the pressure- Is lowered.

In order to solve the problems of the prior art as described above, it is an object of the present invention to provide a light diffusion pressure-sensitive adhesive composition which is excellent in dispersibility and storage stability of a pressure-sensitive adhesive composition and can improve workability.

Another object of the present invention is to provide a light diffusion adhesive composition capable of suppressing moire phenomenon caused by a prism sheet when applied to a polarizing plate and at the same time having an excellent degree of polarization and preventing a decrease in luminance, thereby improving the visibility of a liquid crystal display .

Another object of the present invention is to provide a polarizing plate in which a light diffusion adhesive layer made of the above light diffusion adhesive composition is laminated.

It is another object of the present invention to provide a liquid crystal display device having the polarizing plate on at least one surface of a liquid crystal cell.

In order to achieve the above object, the present invention provides a light diffusion adhesive composition comprising an acrylic pressure sensitive adhesive resin, a crosslinking agent and a light diffusing agent, wherein the light diffusing agent is an inorganic particle containing a crosslinking agent and surface modified with a hydrophobic alkoxysilane compound .

The present invention also provides a polarizing plate in which a light diffusion adhesive layer made of the above light diffusion pressure sensitive adhesive composition is laminated.

The present invention also provides a liquid crystal display having the polarizing plate on at least one side of a liquid crystal cell.

According to the present invention, it is possible to improve the workability by improving the dispersibility and storage stability of the pressure-sensitive adhesive composition, to suppress the moire phenomenon caused by the prism sheet when applied to a polarizing plate, And a polarizing plate and a liquid crystal display using the same, which are improved to improve the visibility of a display device.

Disclosed is a light diffusion pressure-sensitive adhesive composition which is excellent in storage stability, can suppress a moire phenomenon, has an excellent polarization degree and can prevent a decrease in luminance and can improve the visibility of a liquid crystal display device, a polarizing plate and a liquid crystal display ≪ / RTI >

Hereinafter, the present invention will be described in detail.

The light-diffusing pressure-sensitive adhesive composition of the present invention comprises an acrylic pressure-sensitive adhesive resin, a crosslinking agent, and a light-diffusing agent.

As the acrylic pressure-sensitive adhesive resin, a copolymer of a (meth) acrylate monomer having an alkyl group of 1 to 14 carbon atoms as an acrylic copolymer and a monomer having a functional group capable of crosslinking with the following crosslinking agent can be used. Here, '(meth) acrylate' means both acrylate and methacrylate.

Specific examples of the (meth) acrylate monomer having 1 to 14 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, (Meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) acrylate, n-decyl (meth) acrylate, n-decyl (meth) acrylate, isononyl Acrylate, n-tetradecyl (meth) acrylate, pentafluorooctyl acrylate, and 6- (1-naphthyloxy) -1-hexyl acrylate. These may be used singly or in combination of two or more kinds. Can be used.

The (meth) acrylate monomer having 1 to 14 carbon atoms is preferably contained in an amount of 50 to 99% by weight based on the total monomer content (100% by weight) used in the production of the acrylic copolymer.

The monomer having a cross-linking agent and a cross-linkable functional group reacts with the cross-linking agent to give a cohesive force or a cohesive strength by chemical bond so that the cohesive force does not break down under high temperature or humidity conditions. For example, Containing monomer, an amino group-containing monomer, an imide group-containing monomer, an epoxy group-containing monomer, and an ether group-containing monomer, a carboxyl group-containing monomer, a cyano group-containing monomer, a vinyl ester, an aromatic vinyl compound, a carboxyl group-containing monomer, an acid anhydride group-containing monomer, Group-containing monomers, etc. These may be used alone or in combination of two or more.

Examples of the sulfonic acid group-containing monomer include styrenesulfonic acid, allylsulfonic acid, 2- (meth) acrylamido-2-methylpropanesulfonic acid, (meth) acrylamidopropanesulfonic acid, sulfopropyl (meth) ) Acryloyloxynaphthalenesulfonic acid, sodium vinylsulfonate, and the like.

As the phosphate group-containing monomer, 2-hydroxyethyl acryloyl phosphate can be mentioned.

Examples of the cyano group-containing monomer include (meth) acrylonitrile.

Examples of the vinyl esters include vinyl acetate, vinyl propionate, and vinyl laurate.

Examples of the aromatic vinyl compound include styrene, chlorostyrene, chloromethylstyrene,? -Methylstyrene, and other substituted styrenes.

Examples of the carboxy group-containing monomer include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid and isocrotonic acid.

Examples of the acid anhydride-containing monomer include maleic anhydride, itaconic anhydride, and acid anhydrides thereof.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (Meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) (Meth) acrylamide, vinyl alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether and the like.

Examples of the amide group-containing monomer include (meth) acrylamide, diethylacrylamide, N-vinylpyrrolidone, N, N-dimethyl (meth) acrylamide, N, N'-methylenebisacrylamide, N, N-dimethylaminopropyl (meth) acrylamide, diacetone acrylamide and the like.

Examples of the amino group-containing monomer include aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, (meth) acryloylmorpholine, .

Examples of the imide group-containing monomer include cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide and itaconimide.

Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, and allyl glycidyl ether.

Examples of the ether group-containing monomer include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, phenoxyethyl And morpholine.

The monomer having a crosslinkable functional group is preferably contained in an amount of 1 to 50% by weight based on the total monomer content (100% by weight) used in the production of the acrylic copolymer.

The acrylic copolymer having the above components may be prepared by a conventional method such as a solution polymerization method, a photopolymerization method, a bulk polymerization method, a suspension polymerization method and an emulsion polymerization method, and is preferably prepared by a solution polymerization method.

The acrylic copolymer generally has a weight average molecular weight (in terms of polystyrene) measured by Gel Permeation Chromatography (GPC) of usually 50,000 to 2,000,000, preferably 100,000 to 1,800,000, more preferably 500,000 to 1,500,000 to be.

The crosslinking agent is an isocyanate compound, an epoxy compound, a melamine resin, an aziridine compound or the like which is used for enhancing the cohesive force of the pressure-sensitive adhesive composition by adequately crosslinking the acrylic copolymer, and preferably an isocyanate compound or an epoxy compound is used . These may be used alone or in combination of two or more.

Examples of the isocyanate compound include tolylene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, 2,4-diphenylmethane diisocyanate, 4,4-diphenylmethane diisocyanate, isophorone diisocyanate, tetramethyl xylene diisocyanate , Naphthalene diisocyanate, and the like.

Examples of the epoxy compound include ethylene glycol diglycidyl ether, triglycidyl ether, trimethylolpropane triglycidyl ether, N, N, N ', N'-tetraglycidyldiamine, glycerin diglycidyl ether, , 3-bis (N, N-diglycidylaminomethyl) cyclohexane, and the like.

Examples of the melamine resin include hexamethylol melamine.

Examples of the aziridine compound include N, N'-toluene-2,4-bis (1-aziridinecarboxamide), N, N'-diphenylmethane-4,4'- Id), triethylene melamine, bisisopropanoyl-1- (2-methyl aziridine), and tri-1-aziridinyl phosphine oxide.

The cross-linking agent is preferably contained in an amount of 0.01 to 15 parts by weight based on 100 parts by weight of the acrylic pressure-sensitive adhesive resin (based on the solid content). If the content is less than 0.01 part by weight, the adhesive force or the cohesive force of the pressure-sensitive adhesive is not good. If the content exceeds 15 parts by weight, the compatibility may decrease and surface migration may occur.

As the crosslinking agent, an ultraviolet curable polyfunctional (meth) acrylate monomer may be used. Specific examples include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) (Meth) acrylate, diacryloyloxyethyl isocyanurate, di (methoxy) acrylate, di (methoxy) acrylate, ) Diacrylate such as dimethylolcyclohexane diacrylate, dimethyoledicyclopentane diacrylate, ethylene oxide modified hexahydrophthalic acid diacrylate, tricyclodecane dimethanol acrylate, neopentyl glycol modified trimethylolpropane diacrylate and adamantanediacrylate Monomer; (Meth) acrylate such as trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri Trifunctional monomers such as tri (meth) acrylate and tris (acryloxyethyl) isocyanurate; Tetrafunctional monomers such as diglycerin tetra (meth) acrylate and pentaerythritol tetra (meth) acrylate; Pentafunctional monomers such as propionic acid-modified dipentaerythritol penta (meth) acrylate; And hexafunctional monomers such as caprolactone-modified dipentaerythritol hexa (meth) acrylate. These may be used alone or in combination of two or more.

The ultraviolet curable multi-functional (meth) acrylate monomer is preferably included in an amount of 0.1 to 30 parts by weight based on 100 parts by weight of the acrylic pressure-sensitive adhesive resin (based on the solid content).

The ultraviolet curable polyfunctional (meth) acrylate monomer may be used in combination with a photopolymerization initiator that generates radicals or cations by irradiation with ultraviolet light.

Specific examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- hydroxycyclohexyl phenyl ketone , 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan- ) Ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methyl anthraquinone, 2-ethyl anthraquinone, 2- Anthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, acetophenone dimethyl Ketal, p-dimethylaminobenzoic acid S LE and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and the like, and these may be used alone or in combination of two or more. The photopolymerization initiator may be contained in an amount of usually 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight based on 100 parts by weight of the acrylic pressure-sensitive adhesive resin (based on the solid content).

The light diffusing agent is an inorganic particle containing a crosslinking agent and surface-modified with a hydrophobic alkoxysilane compound.

The inorganic particles are particles containing pores, and specific examples thereof are selected from the group consisting of silica, potassium carbonate, barium sulfate, titanium dioxide, aluminum hydroxide, glass, talc, mica, white carbon, magnesium oxide and zinc oxide And it is particularly preferable to use silica.

As the inorganic particles, those having a shape such as a sphere, a concavo-convex shape, or a porous shape can be used, but in the present invention, it is preferable to use spherical shape non-iron type or porous type particles. Particularly, in the case of a porous particle, it contains a large amount of pores, which is advantageous in that the crosslinking agent can be easily adsorbed by the surface treatment of the silane coupling agent. When mixed with the acrylic pressure sensitive adhesive resin, the acrylic pressure sensitive adhesive resin penetrates into the particles As a result, the moire phenomenon caused by the prism sheet can be more efficiently improved.

The average pore size of the pores is preferably 0.05 to 20 nm, and the pore size is more preferably 2 to 10 times the size of the cross-linking agent molecule so that the cross-linking agent contained in the inorganic particles can be easily adsorbed in the pores. In order to adsorb an appropriate amount of the crosslinking agent, the pore volume is preferably 0.1 to 1.1 cc / g, and the specific surface area is preferably 10 to 1,000 m 2 / g.

The inorganic particles may be pretreated with a silane coupling agent to facilitate the physical adsorption of the crosslinking agent. Through such pretreatment, the surface of the pores existing in the inorganic particles is changed from hydrophilic to hydrophobic, which makes it possible to more easily adsorb the crosslinking agent and improve the compatibility with the acrylic pressure sensitive adhesive resin.

Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl Silane coupling agents containing an epoxy group such as ethyltrimethoxysilane; Aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) An amino group-containing silane coupling agent; (Meth) acrylic group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane; And an isocyanate group-containing silane coupling agent such as 3-isocyanate propyltriethoxysilane. The content of the silane coupling agent may be 0.1 to 10 parts by weight, preferably 0.3 to 3.0 parts by weight based on 100 parts by weight of the inorganic particles.

The crosslinking agent contained in the inorganic particles is intended to increase the bonding force between the acrylic pressure-sensitive adhesive resin and the light-diffusing agent and to ensure that the inorganic particles do not aggregate with each other and are well dispersed and have a polyfunctional group capable of causing a crosslinking reaction through exposure to a heat source The kind of the crosslinking agent is not particularly limited. Specific examples include acrylic acid or methacrylic acid esters of diols such as butanediol diacrylate; Acrylic acid or methacrylic acid esters of triols such as glycerol; And acrylic acid or methacrylic ester of tetrol such as pentaerythritol. Further, a polyvinyl crosslinking agent such as substituted or unsubstituted divinylbenzene, a bifunctional urethane acrylate or a mixture thereof may, for example, be mentioned. The cross-linking agent may be used in a content compatible with the known use and the retention of the adhesive property, and the molecular weight of the cross-linking agent, the degree of the polyfunctional functional group, and the content may be considered. The content of the crosslinking agent may be 1 to 50 parts by weight based on 100 parts by weight of the inorganic particles.

The hydrophobic alkoxysilane compound is added to the inorganic particles to impart hydrophobicity to improve compatibility with the acrylic pressure sensitive adhesive resin. The hydrophobic alkoxysilane compound is preferably selected from the group consisting of tridecyltrimethoxysilane, tridecylmethyldimethoxysilane, undecyltrimethoxysilane, Alkylalkoxysilane compounds such as silydimethoxysilane, octadecyldimethylmethoxysilane, octadecyldimethylethoxysilane, decyltrimethoxysilane, hexyltrimethoxysilane and hexylmethyldimethoxysilane; Octenyltrimethoxysilane, hexenylmethyldimethoxysilane, etc .; Aromatic alkoxysilanes such as phenyltriethoxysilane, benzyltriethoxysilane, phenylethyltriethoxysilane and quaternary butylpentyldimethylmethoxysilane; And alkoxysilane compounds containing cyclic hydrocarbon functional groups such as bicycloheptenyl triethoxy silane, bicyclic heptanyl methyl dimethoxy silane and cyclohexyldimethylethoxy silane; 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, etc. An epoxy group-containing silane coupling agent; Aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) An amino group-containing silane coupling agent; (Meth) acrylic group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane; And isocyanate group-containing silane coupling agents such as 3-isocyanatepropyltriethoxysilane, but are not limited thereto. The content of the hydrophobic alkoxysilane compound may be 3 to 50 parts by weight based on 100 parts by weight of the inorganic particles.

The light diffusing agent as described above may be prepared by physically adsorbing a crosslinking agent to an inorganic particle and then surface-modifying the crosslinked agent with a hydrophobic alkoxysilane compound. Specifically, the surface of the pores present in the inorganic particles is treated by a conventional surface treatment method using a silane coupling agent. Subsequently, the solution obtained by dissolving the crosslinking agent in the nonpolar solvent is impregnated with the inorganic particles, and then the nonpolar solvent is removed to physically adsorb the crosslinking agent to the inorganic particles. The nonpolar solvent may be ethyl acetate, toluene, ether, acetone, methyl ethyl ketone, benzene, chloroform, hexane or methylene chloride at a volume of 2 to 3 times the pore volume of the inorganic particles. Next, the inorganic particles adsorbed by the crosslinking agent are mixed with a polar solvent and a hydrophobic alkoxysilane compound to prepare a slurry. Water and a catalyst are then added to adjust the pH and the surface modification reaction at a temperature below the melting point of the crosslinking agent. After sufficient reaction for a period of time in which an unreacted product of the hydrophobic alkoxysilane compound is not detected, the filtrate is separated and washed with a polar solvent to prepare a light diffusing agent. As the polar solvent, monohydric or dihydric alcohols such as ethanol, methanol, isopropyl alcohol and the like can be used. When acid catalysts such as hydrochloric acid, nitric acid, etc., strong acid such as acetic acid, formic acid, etc. are used, the pH may be 2 to 5. When caustic soda and ammonia water are used as the alkali catalyst, the pH is preferably 8 to 10 .

The light diffusing agent of the present invention having the above-mentioned structure can be suitably used as a light-diffusing agent in the case of using organic particles such as acrylic resin, polystyrene resin, styrene-acrylic copolymer resin, polyethylene resin, epoxy resin, swelling, and viscosity increase, and the storage stability is deteriorated. In addition, when inorganic particles are used, precipitation occurs due to deterioration of compatibility with acrylic resin.

The light diffusing agent may have an average diameter of 3 to 30 mu m, preferably 5 to 25 mu m. From the standpoint of the uniformity of the light diffusion adhesive layer made of the composition containing particles as the light diffusing agent, it is generally preferable that the average diameter of the particles is uniform. When the average diameter is less than 3 탆, the dispersibility with the acrylic pressure sensitive adhesive resin becomes poor, and when small particles are stacked in multiple layers on the pressure sensitive adhesive layer, reverse scattering occurs, and the degree of polarization and brightness may be lowered. When the average diameter exceeds 30 탆, the process margin of the thickness of the particle addition pressure-sensitive adhesive layer may be lowered and the durability of adhesion may be lowered.

Since the light diffusing agent as described above is in the form of powder, when added directly to an acrylic pressure sensitive adhesive resin having a high viscosity, dispersion stability is lowered and the light diffusing agent particles are not uniformly distributed in the pressure sensitive adhesive resin. Therefore, it is preferable that the light diffusing agent is completely dispersed in a solvent and then added to the pressure-sensitive adhesive resin. The solvent for dispersing the light-diffusing agent is not particularly limited. For example, the same solvent as that used in the production of the acrylic pressure-sensitive adhesive resin may be used. As the acetate-based, benzene-based or ketone-based solvent excellent in dispersibility and solvent resistance to inorganic or organic particles, ethyl acetate, toluene, Xylene, methyl ethyl ketone, or the like may be used.

The light-diffusing agent is preferably contained in an amount of 5 to 50 parts by weight, more preferably 20 to 40 parts by weight, based on the acrylic pressure-sensitive adhesive resin (based on the solid content). When the content is less than 5 parts by weight, the haze value becomes small and the moiré effect becomes strong. When the content exceeds 50 parts by weight, the haze value becomes large, the degree of polarization becomes low, and the luminance and adhesion durability are deteriorated.

In the present invention, the difference (| n ₁ -n ₂ |) between the refractive index n ₁ of the acrylic pressure-sensitive adhesive resin and the refractive index n ₂ of the light diffusing agent may be 0.01 to 0.15, preferably 0.01 to 0.1 , And more preferably 0.04 to 0.07. When the refractive index difference is less than 0.01, a large amount of the light diffusing agent must be added to the acrylic pressure-sensitive adhesive resin, so that the sticking durability is deteriorated. When the refractive index difference is more than 0.15, a small amount of the light diffusing agent can be added.

The light-diffusing pressure-sensitive adhesive composition containing the above-described components may be added to the liquid crystal cell or the substrate in an amount of 0.005 to 100 parts by weight, based on 100 parts by weight of the acrylic pressure-sensitive adhesive resin (based on the solid content) 5 parts by weight.

The light-diffusing pressure-sensitive adhesive composition may further contain additives such as a tackifier resin, an antioxidant, a corrosion inhibitor, a leveling agent, a surface lubricant, a dye, and the like to control adhesion, cohesion, viscosity, elastic modulus, glass transition temperature, antistatic property, , A pigment, a defoaming agent, a filler, an antistatic agent or a light stabilizer.

The polarizing plate of the present invention is characterized in that a light diffusion pressure-sensitive adhesive layer composed of the above light diffusion pressure-sensitive adhesive composition is laminated.

The polarizer includes a polarizer (or a polarizing film), and on one side of the polarizer, a polarizer protective film for protecting the polarizer, a pressure-sensitive adhesive layer to be in contact with the liquid crystal cell, and a release film are laminated in this order, Layer structure in which a polarizer protective film is provided on the other surface of the substrate.

As the polarizer, a film made of a polyvinyl alcohol resin and having a dichroic dye adsorbed and oriented can be used. As the polyvinyl alcohol resin constituting the polarizer, a copolymer of polyvinyl acetate, which is a homopolymer of vinyl acetate, and vinyl acetate and other monomer copolymerizable therewith, may be used. Examples of other monomers copolymerizable with vinyl acetate at this time include unsaturated carboxylic acids, unsaturated sulfonic acids, olefins, vinyl ethers, and acrylamides having an ammonium group. The thickness of the polarizer is not particularly limited, and can be made to a conventional thickness.

The polarizer protective film is preferably excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, and the like, and examples thereof include polyester films such as polyethylene terephthalate, polyethylene isophthalate and polybutylene terephthalate; Cellulose-based films such as diacetylcellulose and triacetylcellulose; Polycarbonate film; Acrylic films such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; Styrene-based films such as polystyrene and acrylonitrile-styrene copolymer; Polyolefin-based films such as polyethylene, polypropylene, cyclo-based or norbornene-based polyolefin-based films, and ethylene propylene copolymers; Polyimide-based films; Polyethersulfone-based films; A sulfone-based film, and the like, and their thickness is not particularly limited.

The release film is a film for protecting the light diffusion pressure-sensitive adhesive layer. The type of the release film is not particularly limited as long as it is a film ordinarily used in the art. Specific examples thereof include polyolefins such as polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene- A polyolefin-based film such as an ethylene-vinyl alcohol copolymer; Polyester films such as polyethylene terephthalate, polyethylene naphthalate and polybutylene terephthalate; Polyamide-based films such as polyacrylate, polystyrene, nylon 6, and partially aromatic polyamide; Polyvinyl chloride films; Polyvinylidene chloride films; Or a polycarbonate film. These may be appropriately subjected to a releasing treatment by a silicone system, a fluorine system, a silica powder, or the like.

The method for laminating the light-diffusing pressure-sensitive adhesive layer on the polarizing plate is not particularly limited as long as it is a method commonly used in the art. For example, the pressure-sensitive adhesive composition may be applied on a polarizer protective film by a method such as a flow casting method and a bar-coater, an air knife, a gravure, a reverse roll, a kiss roll, It can be applied directly by suitable spreading method using a coating method such as spray or blade method, followed by drying and laminating. Alternatively, a pressure-sensitive adhesive layer may be formed on the silicone-coated release film by the same application method as described above, and then the pressure-sensitive adhesive sheet may be laminated on the polarizer protective film by using a roll pressing apparatus. When the pressure-sensitive adhesive composition contains an ultraviolet curable polyfunctional (meth) acrylate monomer as a crosslinking agent, it is preferable to irradiate ultraviolet rays after the pressure-sensitive adhesive composition is applied or laminated on a polarizer protective film using a roll pressing apparatus Do.

The thickness of the light-diffusing pressure-sensitive adhesive layer can be adjusted according to the adhesive force, and is preferably 3 to 100 μm, and more preferably 10 to 50 μm.

The light diffusion adhesive layer preferably has a haze value of 30 to 70% and a transmission sharpness value of 20 to 120, more preferably a haze value of 40 to 70% and a transmission clearness value of 20 to 100. When the haze value is less than 30% and the transmission sharpness value is more than 120, the light diffusion is reduced and the moire phenomenon occurs. When the haze value is more than 70% and the transmission sharpness value is less than 20, The polarization degree is lowered.

Further, the light diffusion pressure-sensitive adhesive layer has a luminance lowering rate of less than 20%, preferably less than 15%, as compared with the pressure-sensitive adhesive layer to which no diffusion agent is added. When the luminance decreasing rate is 20% or more, the intensity of light generated in the backlight unit must be increased, resulting in an increase in power consumption and heat generation. Particularly, in the case of a notebook PC, there is a problem that the battery use time is shortened due to an increase in power consumption.

Further, the light diffusion adhesive layer preferably has a degree of polarization of 99.94% or more, more preferably 99.95% or more, as defined by the following formula (1). When the degree of polarization is in the above range, there is no significant decrease in contrast, so that a clear image can be realized.

The degree of polarization (P) = [(T ₁ - T ₂ ) / (T ₁ + T ₂ )] ^1/2

Wherein T ₁ is the parallel transmittance obtained when the pair of polarizing plates are arranged in parallel with the absorption axis, and T ₂ is the orthogonal transmittance obtained when the pair of polarizing plates are arranged so that the absorption axes are perpendicular to each other. )

FIG. 3 is a cross-sectional view showing the polarizing plate of the present invention. 3, polarizer protective films 31 and 33 are laminated on both surfaces of the polarizer 32, and polarizer protective films 31 and 33 are laminated on the polarizer protective film 31, Sensitive adhesive layer 34 is laminated on the light-diffusing layer. Fig. 3 shows an example of the polarizing plate of the present invention, and it is obvious that the polarizing plate is also applicable to a polarizing plate in which a polarizing protective film is laminated on only one side of the polarizing plate.

The polarizing plate as described above can be applied to all liquid crystal display devices, It can be used as an upper plate and a lower plate polarizer. In particular, it is more preferably used as a lower plate polarizer of a transmissive liquid crystal display device. When a pressure-sensitive adhesive layer having a light diffusion function is applied to an upper plate of a liquid crystal display device, distorted light (moire phenomenon) caused by the prism sheet passes through the liquid crystal cell, so that it is difficult to describe a clear image. Therefore, it is preferable that light is transmitted to the liquid crystal cell after the distortion of the light is solved through the light diffusion adhesive layer of the lower plate before transmitting the distorted light to the liquid crystal cell.

Further, the liquid crystal display of the present invention is characterized in that a polarizing plate in which the light diffusion adhesive layer is laminated on at least one surface of a liquid crystal cell is provided.

FIG. 4 is a cross-sectional view illustrating a liquid crystal display according to an embodiment of the present invention. 4, the liquid crystal display 100 of the present invention includes a liquid crystal cell 50, a top polarizer 40 on the viewer side of the liquid crystal cell 50, and a light diffusion adhesive layer on the backlight unit side A liquid crystal panel in which the lower plate polarizer 30 is laminated, and a direct-type backlight unit 20.

In the present invention, since the liquid crystal display device is well known to those skilled in the art, detailed description of each configuration will be omitted.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

In the following Synthesis Examples, Examples and Comparative Examples, "%" and "parts" indicating the contents are on a weight basis unless otherwise specified.

Synthesis Example 1. Preparation of acrylic copolymer

A four neck jacket reactor 1L was equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen gas inlet tube. The reactor was purged with nitrogen gas, and then 120 parts of ethyl acetate, 98 parts of butyl acrylate, 0.5 part of acrylic acid and 1.4 parts of 2-hydroxyethyl acrylate were charged, and the temperature of the reactor was raised to 50 캜. Then, a solution in which 0.1 part of 2,2'-azobisisobutyronitrile (AIBN) was completely dissolved in 10 parts of ethyl acetate was added dropwise to the reactor. The reaction was continued for an additional 5 hours while maintaining the external temperature of the jacket at 50 占 폚. After completion of the reaction, the solution was diluted with ethyl acetate to obtain an acrylic copolymer solution having a solid content of 20%. The weight average molecular weight of the prepared copolymer solution by GPC was 1,500,000 and the refractive index was 1.42.

Production Example 1. Preparation of light diffuser A

10 kg of silica having a specific surface area of 300 m 2 / g, an average diameter of 20 μm and a pore volume of 0.5 cc / g (manufactured by ABC Nanotech) was weighed. 0.3 kg of Aminosilane A6070 (manufactured by APR Silane Technology) was dissolved in 10 L of ethanol, and the above silica was added thereto to prepare a slurry. Acetic acid was added to the slurry as a catalyst at room temperature to adjust the pH of the slurry to 5, reacted for 5 hours, and then filtered. The slurry was washed three times with 3 L of ethanol and dried thoroughly for 24 hours in a vacuum drier maintained at 70 ° C . In order to physically adsorb the cross-linking agent to the recovered silica, a zero-gravity mixer (F-20, manufactured by Seiji Industry Co., Ltd.) equipped with a solvent supply device, an indirect heating device and a vacuum solvent recovery device was used. After all of the recovered silica was added to the zero-gravity mixer, 1 kg of Ebecryl ^TM 270 (acrylated urethane having an average molecular weight of 1500, manufactured by Rad Cure Specialty Chemicals) was dissolved in 10 L of ethyl acetate to prepare a crosslinking agent solution, Was placed in the feeder and wetted at room temperature while adding to the silica at a rate of 0.2 L / min while maintaining the rotor speed of the zero-gravity mixer at 100 rpm. After the crosslinker solution was completely added, mixing was continued for another hour. Thereafter, the temperature of the mixer was raised to 50 DEG C, the valve of the vacuum solvent recovery device was opened to collect the ethyl acetate as the solvent, the sample was collected in the middle, and the solvent recovery was stopped with an infrared weight- The cross-linking agent Ebecryl ^TM 270 recovered the adsorbed silica.

2 kg of alkoxysilane Z-6070 (manufactured by Dow Corning) was gradually added to a solution dissolved in a mixed solvent of 2 kg of ethanol and 20 kg of ion-exchanged water for hydrophobic modification of the surface of the obtained silica, To prepare a slurry. Ammonia water at a concentration of 25% by weight was added to the prepared slurry to adjust the pH of the slurry to 8 to 9, and the reaction was allowed to proceed at room temperature for 24 hours. After completion of the reaction, the resultant was filtered, washed again with 2.5 L of ethanol, and dried in a vacuum drier maintained at 50 캜 for 24 hours to obtain about 12 kg of a silica light diffusing agent containing a crosslinking agent and surface modified with a hydrophobic alkoxysilane compound.

Production Example 2. Production of light diffusing agent B

A light diffusing agent B was prepared in the same manner as in Preparation Example 1, except that silica having an average diameter of 8 탆 was used.

Production Example 3. Production of light diffusing agent C

A light diffusing agent C was prepared in the same manner as in Preparation Example 1, except that silica having an average diameter of 3 탆 was used.

Production Example 4. Production of light diffusing agent D

A light diffusing agent D was prepared in the same manner as in Preparation Example 1, except that silica having a specific surface area of 100 m < 2 > / g, an average diameter of 8 m and a pore volume of 0.05 cc / g was used.

Example 1

100 parts of the acrylic copolymer resin (based on the solids content) prepared in Synthesis Example 1, 0.8 part of trimethylolpropane-modified tolylene diisocyanate (Coronate L, manufactured by Nippon Polyurethane Industry) as a crosslinking agent, 0.8 part of 3-glycidoxypropyltrimethoxy 0.15 part of silane (KBM-403) and 30 parts of a light diffusing agent A (average diameter: 20 탆, refractive index: 1.46, manufactured by ABIS Nanotek Co., Ltd., Si ⁺ 120MSMC) prepared in Production Example 1 was dispersed in ethyl acetate solvent And the mixture was diluted with ethylacetate to a final concentration of 13% to prepare a pressure-sensitive adhesive composition.

A part of the prepared pressure-sensitive adhesive composition solution was stored for a pot life test, and the remaining pressure-sensitive adhesive composition was dried on a plurality of PET films (25 cm x 20 cm) coated with a release agent using an applicator, And dried for 3 minutes in a forced circulation hot air drier of 100 ° C oven to prepare a light diffusion adhesive sheet. In some of these sheets, another release film was laminated on the pressure-sensitive adhesive layer to laminate it to form NCF (non-carrier film). To measure physical properties such as haze, transmission sharpness and moire phenomenon, ° C.), and the remaining part of the sheets was adhered to a conventional polarizing plate to evaluate optical characteristics (polarization degree, luminance).

Example 2

35 parts of the light diffusing agent B (average diameter: 8 탆, refractive index: 1.46, manufactured by ABIS Nanotek Co., Ltd., product name: Si ⁺ 190Z) prepared in Production Example 2 was used and the thickness of the pressure-sensitive adhesive after drying was 15 탆 The same procedure as in Example 1 was carried out.

Example 3

Except that 35 parts of the light diffusing agent C (average diameter: 3 탆, refractive index: 1.46, manufactured by ABIS Nanotech Co., Ltd.) prepared in Production Example 3 was used and the thickness of the pressure-sensitive adhesive after drying was 15 탆. . ≪ / RTI >

Example 4

Except that 35 parts of the light diffusing agent D (average diameter: 8 占 퐉, refractive index: 1.55, manufactured by Avisco Nanotech Co., Ltd.) prepared in Production Example 4 was used and the thickness of the pressure-sensitive adhesive after drying was 15 占 퐉. . ≪ / RTI >

Comparative Example 1

Except that 35 parts of silica particles (average diameter: 8 占 퐉, refractive index: 1.46, manufactured by Avisco Nanotech Co., Ltd.) containing no crosslinking agent as a light diffusing agent and having a thickness of 15 占 퐉 after drying were used The same procedure as in Example 1 was carried out.

Comparative Example 2

Except that 40 parts of polymethyl methacrylate organic particles (average diameter: 10 탆, refractive index: 1.49, trade name: MX-1000, manufactured by Soken Chemical & Engineering Co., Ltd.) was used as the light diffusing agent and the thickness of the pressure- Was carried out in the same manner as in Example 1 above.

division Copolymer Light diffuser Refractive index difference
| (n ₁ -n ₂ ) | adhesive
thickness
(탆) content Refractive index
(n ₁₎ weapon
particle surface
Modification Organic particles Particle diameter
(탆) content Refractive index
(n ₂ ) Example 1 100 1.42 Silica U - 20 30 1.46 0.04 30 Example 2 100 1.42 Silica U - 8 35 1.46 0.04 15 Example 3 100 1.42 Silica U - 3 35 1.46 0.04 15 Example 4 100 1.42 Silica U - 8 35 1.55 0.13 15 Comparative Example 1 100 1.42 Silica radish - 8 35 1.46 0.04 15 Comparative Example 2 100 1.42 - - PMMA 10 40 1.49 0.07 15

Test Example

The properties of the light-diffusing pressure-sensitive adhesive composition, the pressure-sensitive adhesive sheet and the polarizing plate prepared in the above Examples and Comparative Examples were measured by the following methods, and the results are shown in Table 2 below.

(1) haze

The sheet of NCF (non-carrier film) thus produced was cut into a size of 4 cm x 4 cm and then cut into a size of 4 cm x 4 cm using a haze meter (HZ-1, manufactured by Suga Test Instrument Co., Ltd.) according to JIS K 7361-1 And calculated by the following formula (2).

Haze (%) = diffused light / total transmitted light x 100

(2) Transparency sharpness

The prepared non-carrier film (NCF) sheet was cut into 4 cm x 4 cm pieces and then measured using a transmission sharpness tester (ICM-1T, manufactured by Suga Test Instrument Co., Ltd.). At this time, the transmission sharpness can be measured by using four types of optical combs having width ratios of the arm portion and the list portion of 1: 1 and their widths of 0.125 mm, 0.5 mm, 1.0 mm and 2.0 mm, respectively, and JIS K 7105 The direction of incidence of light was measured by four kinds of optical combs in the vertical direction, and the sum of these values was taken as the sum of the transmission sharpness.

(3) Moire phenomenon

After the produced NCF (non-carrier film) sheet was laminated on a prism sheet of a backlight unit in which a reflection plate, a light source, a diffusion plate and a prism sheet were laminated in order, the generation strength of the moire phenomenon And evaluated based on the following criteria.

◎: Moire phenomenon does not occur at all

○: Moire phenomenon occurs a little

△: Partial occurrence of moire phenomenon

×: Moire phenomenon occurs a lot

(4) Polarization degree

The prepared polarizer plate having the light diffusion adhesive sheet laminated thereon was cut into a size of 4 cm x 4 cm and then measured using an ultraviolet ray spectrophotometer (VAP-7070, manufactured by JASCO). At this time, the polarization degree is defined by Equation 1 described above.

(5) Rate of decrease in luminance

A polarizing plate (lower plate) in which a light diffusion pressure-sensitive adhesive layer was laminated was bonded to an edge type backlight unit as shown in Fig. 1 and then measured using a luminance meter (CA-210, manufactured by Konica Minolta). At this time, the luminance lowering rate was shown based on the luminance value of the polarizing plate (reference example) in which the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition not using the diffusing agent was laminated.

(6) Storage stability

The initial viscosity of the prepared pressure-sensitive adhesive composition (13%) and the viscosity after 7 days of standing were measured, and viscosity changes were measured to evaluate storage stability. At this time, the viscosity was measured using a viscometer (Brookfield LVDV-II + type B (spindle no. 2, 30 rpm)).

○: Viscosity after 7 days / Initial viscosity <2

?: Viscosity after 2? 7 days / initial viscosity <3

×: viscosity after 3 ≦ 7 days / initial viscosity

(7) Dispersibility

The degree of dispersion of the light-diffusing agent in the prepared light-diffusing pressure-sensitive adhesive composition was visually observed and evaluated based on the following criteria.

?: Good dispersibility without causing precipitation of light diffusing agent

?: Partial precipitation of light diffusing agent occurred

X: a lot of light diffusing agent was precipitated and the dispersibility was not good

division Dispersibility Save
stability Hayes
(%) Permeation
definition Moire
Judgment Polarization degree (%)
(Improved visibility) Luminance lowering rate
(%) Example 1 ○ ○ 50 42 ○ 99.970 10 Example 2 ○ ○ 55 64 ○ 99.969 15 Example 3 △ ○ 50 221 △ 99.934 20 Example 4 ○ ○ 89 20 ○ 99.928 40 Comparative Example 1 × ○ - - - - - Comparative Example 2 ○ × 55 89 ○ 99.970 10

As shown in Table 2, it was confirmed that the light-diffusing pressure-sensitive adhesive compositions of Examples 1 to 4 according to the present invention had excellent dispersibility and little change in viscosity and excellent storage stability. In particular, in Examples 1 and 2, the average diameter and the refractive index of the light diffusing agent were also adjusted, thereby improving the moire phenomenon when applied to a pressure-sensitive adhesive sheet and a polarizing plate. In the case of Example 3, the moire phenomenon and transmission sharpness were somewhat lowered by using a light diffusing agent having a relatively small average diameter. In Example 4, the difference in refractive index between the pressure-sensitive adhesive resin and the light diffusing agent was relatively large, , The transmission sharpness was lowered and the degree of polarization was slightly reduced.

On the other hand, in Comparative Example 1 in which silica particles were used as a light diffusing agent, the dispersibility of the light diffusing agent was poor, so that the particles were aggregated together, resulting in precipitation, which was difficult to apply to sheets and polarizing plates. In Comparative Example 2, the viscosity change of the pressure-sensitive adhesive composition was greatest, and the storage stability was greatly reduced.

1 is a cross-sectional view showing an edge type backlight unit,

2 is a cross-sectional view illustrating a direct-type backlight unit,

3 is a cross-sectional view illustrating a polarizing plate in which a light diffusion pressure-sensitive adhesive layer according to an embodiment of the present invention is laminated,

4 is a cross-sectional view illustrating a liquid crystal display device according to an embodiment of the present invention.

Description of the Related Art [0002]

10: Edge type backlight unit 20: Direct type backlight unit

11, 21: light source 12, 22: reflector

13: light guide plate 14, 24: diffusion sheet

15, 25: prism sheet 16, 26: protective sheet

23: lower chassis 27: diffuser plate

30: polarizer (lower plate) 40: polarizer (upper plate)

31, 33, 41, 43: Polarizer protective film

32, 42: polarizer 34: light diffusion pressure-sensitive adhesive layer

44: pressure-sensitive adhesive layer 50: liquid crystal cell

100: liquid crystal display

Claims (10)

An acrylic pressure-sensitive adhesive resin, a crosslinking agent and a light-diffusing agent, wherein the light-diffusing agent is an inorganic particle containing a crosslinking agent and surface-modified with a hydrophobic alkoxysilane compound. The light diffusion adhesive composition according to claim 1, wherein the light diffusing agent has an average diameter of 5 to 25 占 퐉. The optical diffusion adhesive composition according to claim 1, wherein a difference (| n ₁ -n ₂ |) between a refractive index (n ₁ ) of the acrylic pressure sensitive adhesive resin and a refractive index (n ₂ ) of the light diffusing agent is 0.01 to 0.10. The light diffusion adhesive composition according to claim 1, wherein the inorganic particles are at least one selected from the group consisting of silica, potassium carbonate, barium sulfate, titanium dioxide, aluminum hydroxide, glass, talc, mica, white carbon, magnesium oxide, . The method of claim 1, wherein the crosslinking agent contained in the light diffusing agent is selected from the group consisting of acrylic acid or methacrylic acid of diol, triol, and tetrol; Polyvinyl type; And a bifunctional urethane acrylate. The method of claim 1, wherein the hydrophobic alkoxysilane compound is selected from the group consisting of tridecyltrimethoxysilane, tridecylmethyldimethoxysilane, undecyltrimethoxysilane, diundecyldimethoxysilane, octadecyldimethylmethoxysilane, octadecyldimethyl Hexyl trimethoxy silane, hexyl trimethoxy silane, hexyl trimethoxy silane, hexyl trimethoxy silane, phenyl triethoxy silane, benzyl triethoxy silane, phenyl ethyl Triethoxysilane, triethoxysilane, quaternary butylpentyldimethylmethoxysilane, bicycloheptenyltriethoxysilane, bicyclic heptanylmethyldimethoxysilane, cyclohexyldimethylethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N- 2- (aminoethyl) -3-aminopropyl Methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3- Isocyanate-propyltriethoxysilane, and isocyanate-propyltriethoxysilane. The optical diffusion adhesive composition according to claim 1, wherein the pressure-sensitive adhesive layer comprising the light-diffusing pressure-sensitive adhesive composition has a haze value of 30 to 70% and a transmission sharpness of 20 to 120. The optical diffusion adhesive composition according to claim 1, wherein the pressure-sensitive adhesive layer composed of the light-diffusing pressure-sensitive adhesive composition has a degree of polarization of 99.94% or more and a luminance drop of less than 20%. A polarizing plate laminated with a light-diffusing pressure-sensitive adhesive layer comprising the light-diffusing pressure-sensitive adhesive composition according to any one of claims 1 to 8. A liquid crystal display device comprising the liquid crystal cell according to claim 9 on at least one surface thereof.

Images