JP2010231015A - Polarizer protection film, polarizing plate, and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarizer protection film which is hardly peeled from an adhesive layer even when being layered on a polarizer by using an adhesive. <P>SOLUTION: A single layer or a multilayer film having a layer of a thermoplastic resin composition containing 55 to 75 pts.wt. thermoplastic resin and 25 to 45 pts.wt. elastic body particles in which elastic bodies have 10 to 120 nm number average particle diameter is used as the polarizer protection film. The thermoplastic resin is preferably an acrylic resin and the elastic body particles are preferably particles containing an acrylic elastic polymer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polarizer protective film, a polarizing plate formed by laminating the polarizer protective film and a polarizer, and a liquid crystal display device including the polarizing plate and a liquid crystal cell.

  As a polarizing plate used for a liquid crystal display member or the like, a polarizing plate in which a protective film is laminated on at least one surface of a polarizer is usually used. As this protective film, those made of a thermoplastic resin are usually used, but the toughness is insufficient and the film may be easily broken. For this reason, adding an elastic body and improving toughness is examined.

  As a polarizer protective film made of a thermoplastic resin containing an elastic body, for example, JP-A-5-119217 (Patent Document 1) includes 50 to 70 parts by weight of methyl methacrylate, 10 to 20 parts by weight of maleic anhydride, and The weight of acrylic resin / toughness improver comprising acrylic resin comprising 20 to 35 parts by weight of styrene and a toughness improver such as impact-resistant acrylic rubber-methyl methacrylate graft copolymer or butyl-modified acetylcellulose. A polarizing film protecting film comprising a composition having a ratio of 60 to 90/40 to 10 has been proposed. Japanese Patent Application Laid-Open No. 2005-314534 (Patent Document 2) contains 60 to 90% by weight of an acrylic resin containing glutaric anhydride units, 7 to 40% by weight of acrylic elastic particles, and an acrylic elastic body. An acrylic resin film having an average particle diameter of 70 to 300 nm, a breaking elongation of the film of 15% or more, 1% under high tension and a deformation temperature of 100 ° C. or more has been proposed. Films are exemplified, and as examples or comparative examples, examples in which 20 parts by weight of acrylic elastic particles having an average particle diameter of 50 nm, 85 nm, 125 nm, 140 nm, or 205 nm are blended with respect to 80 parts by weight of acrylic resin, Acrylic elastic particles having a particle diameter of 140 nm are 42 parts by weight with respect to 58 parts by weight of acrylic resin and 35 times with respect to 65 parts by weight of acrylic resin Parts, example was blended 7 parts by weight is shown with respect to 93 parts by weight 12 parts by weight or acrylic resin to 88 parts by weight of an acrylic resin.

Japanese Patent Laid-Open No. 5-119217 JP 2005-314534 A

  When a polarizer protective film made of a thermoplastic resin containing a conventional elastic body is laminated with a polarizer using an adhesive, particularly an active energy ray curable adhesive, it may be easily peeled off from the adhesive layer. Accordingly, an object of the present invention is to provide a polarizer protective film made of a thermoplastic resin containing an elastic body, which is difficult to peel off from an adhesive layer even when laminated with a polarizer using an adhesive. There is to do.

  In order to achieve the above object, the present invention provides a single-layer or multilayer polarizer protective film having a layer of a thermoplastic resin composition containing 55 to 75 parts by weight of a thermoplastic resin and 25 to 45 parts by weight of elastic particles. The polarizer protective film is characterized in that the number average particle diameter of the elastic body in the elastic particles is 10 to 120 nm.

  Moreover, according to this invention, the polarizing plate formed by laminating | stacking the said polarizer protective film and polarizer with an adhesive agent is also provided.

  Furthermore, according to this invention, a liquid crystal display device provided with the said polarizing plate and a liquid crystal cell is also provided.

  Even if the polarizer protective film of the present invention is laminated with a polarizer using an adhesive, it is difficult to peel off from the adhesive layer. By using this, the polarizer protective film is not easily peeled off, and further a liquid crystal display device Can be obtained.

(Polarizer protective film)
The polarizer protective film of the present invention is a monolayer or multilayer film having a layer of a thermoplastic resin composition containing 55 to 75 parts by weight of thermoplastic resin and 25 to 45 parts by weight of elastic particles. And the number average particle diameter of the elastic body in the said elastic body particle is 10-120 nm.

  Examples of thermoplastic resins include polyolefin resins such as polyethylene resins and polypropylene resins, polyvinyl chloride resins, polyester resins such as polyethylene terephthalate resins and polyethylene naphthalate resins, polycarbonate resins, norbornene resins, polyurethane resins, and acrylic resins. Resins may be mentioned, and two or more of them may be used as necessary. Among these, acrylic resins are preferably used from the viewpoint of surface hardness, light resistance, and transparency of the polarizer protective film.

  The acrylic resin is preferably a polymer mainly composed of alkyl methacrylate, and may be a homopolymer of alkyl methacrylate, or a monomer other than alkyl methacrylate of 50% by weight or more and alkyl methacrylate. It may be a copolymer of 50% by weight or less. As the alkyl methacrylate, those having 1 to 4 carbon atoms of the alkyl group are usually used, and among them, methyl methacrylate is preferably used. The monomer other than alkyl methacrylate may be a monofunctional monomer having one polymerizable carbon-carbon double bond in the molecule, or two or more polymerizable carbons in the molecule. -A polyfunctional monomer having a carbon double bond may be used, but a monofunctional monomer is preferably used here, and examples thereof include alkyl acrylates such as methyl acrylate and ethyl acrylate, Examples thereof include styrene monomers such as styrene and alkylstyrene, and unsaturated nitriles such as acrylonitrile and methacrylonitrile. When using alkyl acrylate as a copolymerization component, the carbon number is 1-8 normally. The monomer composition of the acrylic resin is preferably 70% by weight or more, more preferably 80% by weight or more, and still more preferably 90% by weight or more based on the total 100% by weight of all monomers. In addition, it is preferably 99% by weight or less.

  The elastic particles are particles containing an elastic body, and may be particles composed of only an elastic body, or may be particles having a multilayer structure having an elastic layer. Examples of the elastic body include olefin-based elastic polymers, diene-based elastic polymers, styrene-diene-based elastic copolymers, and acrylic-based elastic polymers. Among these, an acrylic elastic polymer is preferably used from the viewpoint of the surface hardness, light resistance, and transparency of the polarizer protective film.

  The acrylic elastic polymer may be a polymer mainly composed of alkyl acrylate, may be a homopolymer of alkyl acrylate, or may be a single polymer other than alkyl acrylate of 50% by weight or more and alkyl acrylate. A copolymer with 50% by weight or less of the monomer may be used. As the alkyl acrylate, those having 4 to 8 carbon atoms in the alkyl group are usually used. Examples of monomers other than alkyl acrylate include alkyl methacrylates such as methyl methacrylate and ethyl methacrylate, styrene monomers such as styrene and alkyl styrene, acrylonitrile and methacrylonitrile. Monofunctional monomers such as unsaturated nitriles, alkenyl esters of unsaturated carboxylic acids such as allyl (meth) acrylate and methallyl (meth) acrylate, dialkenyl esters of dibasic acids such as diallyl maleate, And polyfunctional monomers such as unsaturated carboxylic acid diesters of glycols such as alkylene glycol di (meth) acrylate.

  The elastic particles containing the acrylic elastic polymer are preferably multi-layered particles having an acrylic elastic polymer layer, and a polymer layer mainly composed of alkyl methacrylate outside the acrylic elastic body. It may be of a two-layer structure having a three-layer structure having a polymer layer mainly composed of alkyl methacrylate inside the acrylic elastic body. In addition, the example of the monomer composition of the polymer mainly composed of alkyl methacrylate constituting the layer formed on the outside or inside of the acrylic elastic body is the same as the alkyl methacrylate described above as an example of the acrylic resin. This is the same as the monomer composition example of the main polymer. Such acrylic elastic particles having a multilayer structure can be produced, for example, by the method described in Japanese Patent Publication No. 55-27576.

  In the present invention, elastic particles having a number average particle diameter of 10 to 120 nm are used. Thereby, when it laminates | stacks on a polarizer using an adhesive agent, the polarizer protective film which is hard to peel off from an contact bonding layer can be obtained. The number average particle diameter of the elastic body is preferably 50 nm or more, and preferably 100 nm or less.

  In the case of an elastic particle in which the outermost layer is a polymer mainly composed of methyl methacrylate and the acrylic elastic polymer is encapsulated in the polymer, the outermost layer of the elastic particle can be obtained by mixing it with the base acrylic resin. Since the outer layer is miscible with the base acrylic resin, the cross section of the acrylic elastic polymer is stained with ruthenium oxide, and when observed with an electron microscope, the elastic particles are in a state excluding the outermost layer. Observed as particles. Specifically, when using an elastic particle having a two-layer structure in which the inner layer is an acrylic elastic polymer and the outer layer is a polymer mainly composed of methyl methacrylate, the acrylic elastic polymer portion of the inner layer is used. Are observed as single-layered particles, the innermost layer is a polymer mainly composed of methyl methacrylate, the intermediate layer is an acrylic elastic polymer, and the outermost layer is mainly composed of methyl methacrylate. In the case of using a three-layered elastic particle, which is a polymer to be polymerized, as a particle having a two-layered structure in which the inner-layer particle central part is not dyed and only the acrylic elastic polymer part of the intermediate layer is dyed. Will be observed. In the present specification, the number average particle diameter of the elastic body in the elastic body particle is, as described above, when the elastic body particle is mixed with the base resin and the cross section is dyed with ruthenium oxide. It is the number average value of the diameters of the parts observed in FIG.

  The content ratio of the thermoplastic resin and the elastic particles in the thermoplastic resin composition is 55 to 75 parts by weight of the thermoplastic resin and 25 to 45 parts by weight of the elastic particles based on the total of 100 parts by weight of both. is there. Thereby, when it laminates | stacks on a polarizer using an adhesive agent, the polarizer protective film which is hard to peel off from an contact bonding layer can be obtained.

  The thermoplastic resin composition is produced, for example, by obtaining elastic particles and then polymerizing a monomer as a raw material for the thermoplastic resin in the presence thereof to produce a base thermoplastic resin. Alternatively, after obtaining the elastic particles and the thermoplastic resin, they may be produced by mixing them by melt kneading or the like.

  If necessary, the thermoplastic resin composition may include a colorant such as a pigment or a dye, a fluorescent brightener, a dispersant, a heat stabilizer, a light stabilizer, an infrared absorber, an ultraviolet absorber, or an antistatic agent. Further, a compounding agent such as an antioxidant, a lubricant or a solvent may be contained.

  The ultraviolet absorber is added to improve durability by absorbing ultraviolet rays of 400 nm or less. As the ultraviolet absorber, known ones such as a benzophenone ultraviolet absorber, a benzotriazole ultraviolet absorber, and an acrylonitrile ultraviolet absorber can be used. Among them, 2,2'-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2'-hydroxy-3 ' -Tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2,4-di-tert-butyl-6- (5-chlorobenzotriazol-2-yl) phenol, 2,2'-dihydroxy- 4,4′-dimethoxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone and the like are preferably used. Among these, 2,2'-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol) is particularly preferable. The concentration of the ultraviolet absorber can be selected in such a range that the transmittance of the polarizer protective film at a wavelength of 370 nm or less is preferably 10% or less, more preferably 5% or less, and further preferably 2% or less. Examples of the method of containing the ultraviolet absorber include a method of previously blending the ultraviolet absorber into the thermoplastic resin; a method of directly supplying the melt during the melt extrusion molding, and any method may be employed.

  As infrared absorbers, nitroso compounds, metal complexes thereof, cyanine compounds, squarylium compounds, thiol nickel complex compounds, phthalocyanine compounds, naphthalocyanine compounds, triallylmethane compounds, imonium compounds, diimonium compounds, Infrared absorption of naphthoquinone compounds, anthraquinone compounds, amino compounds, aminium salt compounds, carbon black, indium tin oxide, antimony tin oxide, metal oxides belonging to Group 4A, 5A or 6A, carbides, borides, etc. An agent etc. can be mentioned. These infrared absorbers are preferably selected so as to be able to absorb the entire infrared ray (light having a wavelength in the range of about 800 nm to 1100 nm), and two or more types may be used in combination. The amount of the infrared absorber can be appropriately adjusted so that, for example, the light transmittance of the polarizer protective film at a wavelength of 800 nm or more is 10% or less.

  The thermoplastic resin composition preferably has a glass transition temperature Tg in the range of 80 to 120 ° C. Furthermore, the thermoplastic resin composition has a high surface hardness when formed into a film, specifically, a pencil hardness (load 500 g, conforming to JIS K5600-5-4) exceeding 2H. preferable.

  In addition, the thermoplastic resin composition preferably has a flexural modulus (JIS K7171) of 1500 MPa or less from the viewpoint of flexibility of the polarizer protective film. The flexural modulus is more preferably 1300 MPa or less, and still more preferably 1200 MPa or less. This bending elastic modulus varies depending on the type and amount of the thermoplastic resin and elastic particles in the thermoplastic resin composition. For example, the bending elastic modulus generally decreases as the content of elastic particles increases. In addition, the bending elastic modulus is generally smaller when a copolymer of alkyl methacrylate and alkyl acrylate is used as the thermoplastic resin than when a homopolymer of alkyl methacrylate is used. In addition, the elastic elastic particles generally have a lower bending elastic modulus than the three-layered acrylic elastic polymer particles, and the single-layered acrylic elastic polymer particles having the two-layered structure. In general, the bending elastic modulus is smaller when the acrylic elastic polymer particles having the structure are used. In addition, in the elastic particles, the smaller the average particle diameter of the elastic body or the larger the amount of the elastic body, the smaller the flexural modulus is generally. Therefore, the kind and amount of the thermoplastic resin and the elastic particles may be adjusted within the predetermined range so that the bending elastic modulus is 1500 MPa or less.

  In the case where the polarizer protective film has a multilayer structure, the layer that can be present in addition to the thermoplastic resin composition layer is not particularly limited, and, for example, a thermoplastic resin containing no elastic particles or a composition thereof Or a layer made of a thermoplastic resin composition in which the content of the elastic particles and the average particle size of the elastic material in the elastic particles are outside the above specified range. Typically, it has a two-layer or three-layer structure, and may be, for example, a two-layer structure including a layer of the thermoplastic resin composition / a thermoplastic resin not containing elastic particles or a layer of the composition. The thermoplastic resin composition layer / the thermoplastic resin not containing elastic particles or the composition layer / the thermoplastic resin composition layer may be used. What is necessary is just to let the surface of the layer of the said thermoplastic resin composition be a bonding surface with a polarizer in the multilayer protective film of a polarizer.

  Moreover, when making a polarizer protective film into a multilayer structure, you may mutually differ content of an elastic-body particle | grain and each layer of the said compounding agent. For example, a layer containing an ultraviolet absorber and / or an infrared absorber and a layer not containing the ultraviolet absorber and / or the infrared absorber with the layer interposed therebetween may be laminated. Further, the content of the ultraviolet absorber in the thermoplastic resin composition layer may be higher than the content of the ultraviolet absorber in the thermoplastic resin or composition layer containing no elastic particles. Well, specifically, the former is preferably 0.5 to 10% by weight, more preferably 1 to 5% by weight, and the latter is preferably 0 to 1% by weight, more preferably 0 to 0.5% by weight. As a result, ultraviolet rays can be efficiently blocked without deteriorating the color tone of the polarizing plate, and a decrease in the degree of polarization during long-term use can be prevented.

  The thickness of the polarizer protective film is usually 100 μm or less, preferably 80 μm or less, more preferably 40 μm or more and 80 μm or less. When the polarizer protective film has a multilayer structure, the thermoplastic resin composition layer, when there are a plurality of thicknesses, is expressed by the total thickness thereof, and is 20 to 20 times the total thickness of the polarizer protective film. It should be 80%.

  The polarizer protective film preferably has a residual solvent content of 0.01% by weight or less. When the residual solvent amount is in the above range, for example, it is possible to prevent the polarizer protective film from being deformed in a high temperature / high humidity environment, and to prevent the optical performance from being deteriorated. The residual solvent content was determined by placing 50 mg of protective layer in a 4 mm inner diameter glass tube sample container from which moisture and organic substances adsorbed on the surface were completely removed, heating the container at a temperature of 200 ° C. for 30 minutes, and The collected gas can be continuously collected, and the collected gas can be analyzed by a thermal desorption gas chromatography mass spectrometer (TDS-GC-MS).

The polarizer protective film preferably has a moisture permeability of 10 g · m ⁻² day ⁻¹ or more and 200 g · m ⁻² day ⁻¹ or less. By making the moisture permeability of the polarizer protective film within the above-mentioned preferable range, the adhesion between the layers constituting the polarizer protective film can be improved. The moisture permeability can be measured by the cup method described in JIS Z0208 under the test conditions of leaving for 24 hours in an environment of 40 ° C. and 92% RH.

  The polarizing plate of this invention is obtained by laminating | stacking the polarizer protective film of this invention demonstrated above and a polarizer using an adhesive agent. The polarizing plate of the present invention is formed by laminating the polarizer protective film of the present invention on at least one surface of the polarizer, and is formed by laminating the polarizer protective film of the present invention on both sides of the polarizer. The polarizer protective film of the present invention may be laminated on one surface of the polarizer, and another polarizer protective film may be laminated on the other surface. The polarizer protective film of this invention may be laminated | stacked on one side of this, and the protective film may not be laminated | stacked on the other surface.

(Polarizer)
The polyvinyl alcohol resin constituting the polarizer can be obtained by saponifying a polyvinyl acetate resin. Examples of the polyvinyl acetate resin include, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerized with vinyl acetate include unsaturated carboxylic acids, unsaturated sulfonic acids, olefins, vinyl ethers, and acrylamides having an ammonium group. The saponification degree of the polyvinyl alcohol resin is usually 85 to 100 mol%, preferably 98 mol% or more. This polyvinyl alcohol-based resin may be further modified, and for example, polyvinyl polymers modified with aldehydes, polyvinyl acetal, and the like may be used. Moreover, the average polymerization degree of the polyvinyl alcohol-type resin which comprises a polarizer is 1000-10000 normally, Preferably it is 1500-5000.

  A film obtained by forming such a polyvinyl alcohol-based resin into a film (polyvinyl alcohol-based resin film) is used as a raw film for a polarizer. The method for forming a polyvinyl alcohol-based resin is not particularly limited, and can be formed by a known method. Although the film thickness of a polyvinyl alcohol-type resin film is not specifically limited, For example, it is 10-150 micrometers.

  A polarizer usually has a step of uniaxially stretching such a polyvinyl alcohol resin film, a step of dyeing a polyvinyl alcohol resin film with a dichroic dye and adsorbing the dichroic dye, and a dichroic dye adsorbed. It is manufactured through a step of treating the polyvinyl alcohol-based resin film with a boric acid aqueous solution and a step of washing with water after the treatment with the boric acid aqueous solution.

Uniaxial stretching may be performed before dyeing, simultaneously with dyeing, or after dyeing. When uniaxial stretching is performed after dyeing, this uniaxial stretching may be performed before boric acid treatment or during boric acid treatment. Of course, uniaxial stretching can be performed in these plural stages. In uniaxial stretching, it may be uniaxially stretched between rolls having different peripheral speeds, or may be uniaxially stretched using a hot roll. Further, it may be dry stretching such as stretching in the air, or may be wet stretching in which stretching is performed in a state swollen with a solvent.
The draw ratio is usually 3 to 8 times.

  In order to dye a polyvinyl alcohol resin film with a dichroic dye, for example, the polyvinyl alcohol resin film may be immersed in an aqueous solution containing the dichroic dye. Specifically, iodine or a dichroic dye is used as the dichroic dye. In addition, it is preferable that the polyvinyl alcohol-type resin film performs the immersion process to water before a dyeing process.

When iodine is used as the dichroic dye, a method of dyeing a polyvinyl alcohol resin film by dipping it in an aqueous solution containing iodine and potassium iodide is usually employed.
The content of iodine in this aqueous solution is usually 0.01 to 1 part by weight per 100 parts by weight of water, and the content of potassium iodide is usually 0.5 to 20 parts by weight per 100 parts by weight of water. The temperature of the aqueous solution used for dyeing is usually 20 to 40 ° C., and the immersion time (dyeing time) in this aqueous solution is usually 20 to 1800 seconds.

On the other hand, when a dichroic dye is used as the dichroic dye, a method of immersing and dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing a water-soluble dichroic dye is usually employed. The content of the dichroic dye in this aqueous solution is usually 1 × 10 ⁻⁴ to 10 parts by weight, preferably 1 × 10 ⁻³ to 1 part by weight per 100 parts by weight of water. This aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing assistant. The temperature of the aqueous dye solution used for dyeing is usually 20 to 80 ° C., and the immersion time (dyeing time) in this aqueous solution is usually 10 to 1800 seconds.

  The boric acid treatment after dyeing with the dichroic dye is performed by immersing the dyed polyvinyl alcohol-based resin film in a boric acid-containing aqueous solution. The amount of boric acid in the boric acid-containing aqueous solution is usually 2 to 15 parts by weight, preferably 5 to 12 parts by weight per 100 parts by weight of water. When iodine is used as the dichroic dye, this boric acid-containing aqueous solution preferably contains potassium iodide. The amount of potassium iodide in the boric acid-containing aqueous solution is usually 0.1 to 15 parts by weight, preferably 5 to 12 parts by weight, per 100 parts by weight of water. The immersion time in the boric acid-containing aqueous solution is usually 60 to 1200 seconds, preferably 150 to 600 seconds, and more preferably 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is usually 50 ° C. or higher, preferably 50 to 85 ° C., more preferably 60 to 80 ° C.

  The polyvinyl alcohol resin film after the boric acid treatment is usually washed with water. The water washing treatment is performed, for example, by immersing a boric acid-treated polyvinyl alcohol resin film in water. The water temperature in the water washing treatment is usually 5 to 40 ° C., and the immersion time is usually 1 to 120 seconds. After washing with water, a drying process is performed to obtain a polarizer.

  A drying process is normally performed using a hot air dryer and a far-infrared heater. The temperature of a drying process is 30-100 degreeC normally, Preferably it is 50-80 degreeC. The time for the drying treatment is usually 60 to 600 seconds, preferably 120 to 600 seconds.

  In this way, the polyvinyl alcohol resin film is subjected to uniaxial stretching, dyeing with a dichroic dye, and boric acid treatment to obtain a polarizer. The thickness of this polarizer is usually in the range of 5 to 40 μm, preferably in the range of 10 to 35 μm.

(adhesive)
The adhesive used when laminating the polarizer protective film and the polarizer is appropriately selected, but is preferably an active energy ray-curable adhesive, and has a low solvent content of 0 to 2% by weight. More preferred. The solvent content in the adhesive can be measured by gas chromatography or the like.

  Solvents include aliphatic hydrocarbons such as n-hexane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, propanol, isopropanol and n-butanol; acetone and butanone , Ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; esters such as methyl acetate, ethyl acetate and butyl acetate; cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve; halogenation such as methylene chloride and chloroform And hydrocarbons.

  In addition, the active energy ray-curable adhesive is preferably excellent in adhesive applicability when the viscosity measured by a B-type viscometer at 23 ° C. is 50 to 2000 mPa · s. Any known active energy ray-curable adhesive can be used without particular limitation as long as it is colorless and transparent. Examples of the active energy ray-curable compound that is the main component of the active energy ray-curable adhesive include curing by radical polymerization with active energy rays such as a compound having an acryloyl group, a methacryloyl group, or an allyl group as a functional group. (Photo radical polymerizable compound): A compound that has a photocation reaction by an active energy ray such as a compound having a functional group such as epoxy group, oxetane group, hydroxyl group, vinyl ether group, episulfide group, ethyleneimine group, etc. Photocationically polymerizable compound).

  As photoradical polymerizable compounds, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; hydroxyaryl acrylates such as 2-hydroxy-3-phenoxypropyl acrylate; 2-acryloyloxyethyl succinic acid, 2- Acrylic modified carboxylic acids such as acryloyloxyethylphthalic acid; polyethylene glycol diacrylates such as triethylene glycol diacrylate and tetraethylene glycol diacrylate; polypropylene glycol diacrylates such as dipropylene glycol diacrylate and tripropylene glycol diacrylate Other, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, 1,9-no Diol diacrylate, bisphenol A ethylene oxide modified diacrylate, bisphenol A propylene oxide modified diacrylate, dimethylol tricyclodecane diacrylate, trimethylol propane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate Such as epoxy acrylate, urethane acrylate, other acrylates such as acrylic benzoic acid mixed ester of neopentyl glycol; methacrylates thereof, and the like.

  Bisphenol type epoxy resin such as bisphenol A type epoxy resin and bisphenol F type epoxy resin; novolak type epoxy resin such as phenol novolac type epoxy resin and cresol novolac type epoxy resin; aliphatic epoxy resin, alicyclic Type epoxy resin, heterocyclic epoxy resin, polyfunctional epoxy resin, biphenyl type epoxy resin, glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin; alcohol such as hydrogenated bisphenol A type epoxy resin Type epoxy resin; halogenated epoxy resin such as brominated epoxy resin; rubber-modified epoxy resin, urethane-modified epoxy resin, epoxidized polybutadiene, epoxidized styrene-butadiene-styrene Compounds having an epoxy group, such as a polyblock copolymer, an epoxy group-containing polyester resin, an epoxy group-containing polyurethane resin, and an epoxy group-containing acrylic resin; phenoxymethyl oxetane, 3,3-bis (methoxymethyl) oxetane, 3,3- Bis (phenoxymethyl) oxetane, 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, 3-ethyl-3-{[3- (triethoxysilyl) Propoxy] methyl} oxetane, di [1-ethyl (3-oxetanyl)] methyl ether, oxetanylsilsesquioxane, phenol novolac oxetane, 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} Compounds having an oxetanyl group such as benzene It is below.

  These active energy ray-curable compounds may be used alone or in combination.

  A polymerization initiator can be mix | blended with an active energy ray hardening-type adhesive in order to raise the curing reaction efficiency of the above-mentioned active energy ray hardening-type adhesive agent. The polymerization initiator is selected according to the type of active energy ray used. As the polymerization initiator, photo radical polymerization initiators such as acetophenone, benzophenone, thioxanthone, benzoin, and benzoin alkyl ethers; aromatic diazonium salts, aromatic sulfonium salts, aromatic iodonium salts, metathelone compounds, benzoin sulfones Photocationic polymerization initiators such as acid esters; and the like. These can be used individually by 1 type or in combination of 2 or more types.

As the acetophenone photopolymerization initiator, for example, 4-phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1- [ 4- (2-hydroxyethyl) -phenyl] -2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone and the like.

  Examples of the benzoin alkyl ether photopolymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, and benzoin isobutyl ether.

  Examples of the benzophenone photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3′-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexyl phenyl ketone, and the like.

  The cationic photopolymerization initiator may be an ionic photoacid-generating photocationic polymerization initiator or a nonionic photoacid-generating photocationic polymerization initiator. The photocationic polymerization initiator is a photocationic polymerization initiator that is activated by light having a wavelength of 300 nm or more because it can effectively initiate and advance the photocationic polymerization of the photocationically polymerizable compound. Is preferred.

  The ionic photoacid-generating photocationic polymerization initiator is not particularly limited. For example, onium salts such as aromatic diazonium salt, aromatic halonium salt, aromatic sulfonium salt; organometallic complexes such as iron-allene complex, titanocene complex, arylsilanol-aluminum complex; tetrakis (pentafluorophenyl) borate, etc. Examples thereof include a photocationic polymerization initiator having a bulky counter anion. These ionic photoacid-generating photocationic polymerization initiators may be used alone or in combination of two or more.

  Examples of commercially available ionic photoacid-generating photocationic polymerization initiators include “Adekaoptomer” series such as “Adekaoptomer SP150” and “Adekaoptomer SP170” manufactured by Asahi Denka Kogyo Co., Ltd. , A trade name “UVE-1014” manufactured by General Electronics Co., Ltd., a product name “CD-1012” manufactured by Sartomer, and a product name “Photoinitiator 2074” manufactured by Rhodia.

  The nonionic photoacid-generating photocationic polymerization initiator is not particularly limited. For example, nitrobenzyl ester, sulfonic acid derivative, phosphoric acid ester, phenolsulfonic acid ester, diazonaphthoquinone, N-hydroxyimidophosphonate and the like can be mentioned. These nonionic photoacid-generating photocationic polymerization initiators may be used alone or in combination of two or more.

  The compounding quantity of a polymerization initiator is 0.5-20 weight part normally with respect to 100 weight part of active energy ray hardening compounds. The amount is preferably 1 part by weight or more, and more preferably 10 parts by weight or less. When the amount is less than 0.5 parts by weight with respect to 100 parts by weight of the epoxy resin, curing becomes insufficient, and mechanical strength and adhesive strength are lowered. On the other hand, when the amount exceeds 20 parts by weight, the ionic substance in the cured product is increased, so that the hygroscopic property of the cured product is increased and the durability performance may be deteriorated.

  In addition, the active energy ray curable adhesive contains a photosensitizer, antistatic agent, infrared absorber, ultraviolet absorber, antioxidant, organic particles, inorganic oxide particles, metal powder, pigment, dye, etc. May be.

  By using a photosensitizer, the reactivity is improved, and the mechanical strength and adhesive strength of the cured adhesive can be improved. The photosensitizer is not particularly limited, and examples thereof include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo compounds, diazo compounds, halogen compounds, and photoreducible dyes.

  Specific examples of the photosensitizer include benzoin methyl ether, benzoin isopropyl ether, benzoin derivatives such as α, α-dimethoxy-α-phenylacetophenone; benzophenone, 2,4-dichlorobenzophenone, methyl o-benzoylbenzoate, Benzophenone derivatives such as 4,4′-bis (dimethylamino) benzophenone and 4,4′-bis (diethylamino) benzophenone; thioxanthone derivatives such as 2-chlorothioxanthone and 2-isopropylthioxanthone; 2-chloroanthraquinone, 2- Anthraquinone derivatives such as methylanthraquinone; acridone derivatives such as N-methylacridone and N-butylacridone; other, α, α-diethoxyacetophenone, benzyl, fluorenone, xanthone, Examples include uranyl compounds and halogen compounds, but are not limited thereto. These may be used alone or in combination. The photosensitizer is preferably contained in the range of 0.1 to 20 parts by weight when the active energy ray-curable compound is 100 parts by weight. More preferably, 0.1 part-5.0 parts are preferable.

  The polarizing plate of the present invention, the polarizer protective film is bonded to at least one surface of the polarizer via the active energy ray curable adhesive, and then the active energy ray is irradiated to cure the adhesive, It is obtained by fixing the polarizer protective layer to the polarizer.

  There is no particular limitation on the method of applying the adhesive to the polarizer, and various coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater can be used.

  Prior to the bonding of the polarizer protective film to the polarizer, the bonding surface may be subjected to an easy adhesion process such as a saponification process, a corona process, a primer process, or an anchor coating process.

  Usually, light is used as the active energy ray. This light is not particularly limited, and examples thereof include microwaves, infrared rays, visible light, ultraviolet rays, X-rays, and γ rays. In particular, ultraviolet rays are preferably used because of easy handling and relatively high energy.

The light source used for irradiating with ultraviolet rays is not particularly limited, and examples thereof include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, a microwave excitation mercury lamp, and a metal halide lamp. The irradiation intensity is not particularly limited, but the irradiation intensity in the wavelength region effective for activating the polymerization initiator is preferably 0.1 to 100 mW / cm ² . When the light irradiation intensity is less than 0.1 mW / cm ² , the reaction time becomes too long, and when it exceeds 100 mW / cm ² , the adhesive is yellowed or polarized due to radiation heat from the lamp, polymerization reaction heat, or the like. The child itself may be deteriorated. The light irradiation time is appropriately selected according to the curing condition and is not particularly limited, but is set so that the integrated light amount expressed as the product of the irradiation intensity and the irradiation time is 10 to 5000 mJ / cm ^2. It is preferred that

  Furthermore, in the polarizing plate of the present invention, functional layers such as a hard coat layer, an antireflection layer, and an antifouling layer may be formed on the polarizer protective film.

(Hard coat layer)
A hard coat layer is a layer which has a function which raises the surface hardness of a polarizer protective film, and shows hardness more than "H" by the pencil hardness test (a test plate uses a glass plate) shown by JISK5600-5-4. It is preferable. It is preferable that the polarizer protective film provided with such a hard coat layer has a pencil hardness of 4H or more. The material for forming the hard coat layer (hard coat material) is preferably a material that is cured by heat or light. For example, organic hard such as organic silicone, melamine, epoxy, acrylic, urethane acrylate, etc. Coating materials; inorganic hard coat materials such as silicon dioxide; and the like. Among these, urethane acrylate-based and polyfunctional acrylate-based hard coat materials are preferable from the viewpoint of good adhesive strength and excellent productivity.

  The hard coat layer contains various fillers for the purpose of adjusting the refractive index, improving the flexural modulus, stabilizing the volume shrinkage, and improving heat resistance, antistatic properties, and antiglare properties, as desired. it can. Further, the hard coat layer can contain additives such as an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a leveling agent, and an antifoaming agent.

(Antireflection layer)
The antireflection layer is a layer for preventing the transfer of external light, and is laminated on the surface (surface exposed to the outside) of the polarizer protective film directly or via another layer such as a hard coat layer. The polarizer protective film provided with the antireflection layer preferably has an incident angle of 5 °, a reflectance at a wavelength of 430 nm to 700 nm of 2.0% or less, and a reflectance at a wavelength of 550 nm of 1.0% or less. It is preferable.

  The thickness of the antireflection layer is preferably 0.01 μm to 1 μm, more preferably 0.02 μm to 0.5 μm. The antireflection layer has a refractive index smaller than the refractive index of a layer (such as a protective film or a hard coat layer) on which the antireflection layer is laminated, specifically a low refractive index of 1.30 to 1.45. Examples thereof include those composed of a refractive index layer; those obtained by alternately laminating a plurality of low refractive index layers of a thin film made of an inorganic compound and high refractive index layers of a thin film made of an inorganic compound.

The material for forming the low refractive index layer is not particularly limited as long as it has a low refractive index. Examples thereof include a resin material such as an ultraviolet curable acrylic resin, a hybrid material in which inorganic fine particles such as colloidal silica are dispersed in the resin, and a sol-gel material using a metal alkoxide such as tetraethoxysilane. The material for forming these low refractive index layers may be a polymerized polymer, or may be a monomer or oligomer serving as a precursor. Moreover, it is preferable that each material contains the compound containing a fluorine group, in order to provide antifouling property.

As the sol-gel material, a sol-gel material containing a fluorine group is preferably used. Examples of the sol-gel material containing a fluorine group include perfluoroalkylalkoxysilane. Perfluoroalkylalkoxysilane is, for example, CF ₃ (CF ₂ ) _n CH ₂ CH ₂ Si (OR) ₃ (wherein R represents an alkyl group having 1 to 5 carbon atoms, and n is 0 to 12). A compound represented by an integer). Specifically, as perfluoroalkylalkoxysilane, trifluoropropyltrimethoxysilane, trifluoropropyltriethoxysilane, tridecafluorooctyltrimethoxysilane, tridecafluorooctyltriethoxysilane, heptadecafluorodecyltrimethoxysilane , And heptadecafluorodecyltriethoxysilane. Among these, the compound whose said n is 2-6 is preferable.

  The low refractive index layer can be made of a cured product of a thermosetting fluorine-containing compound or an ionizing radiation curable fluorine-containing compound. The cured product preferably has a dynamic friction coefficient of 0.03 to 0.15, and a contact angle with water of 90 to 120 degrees. Examples of the curable fluorine-containing compound include a perfluoroalkyl group-containing silane compound (for example, (heptadecafluoro-1,1,2,2-tetradecyl) triethoxysilane) and the like, and a fluorine-containing polymer having a crosslinkable functional group. Can be mentioned.

  The fluorine-containing polymer having a crosslinkable functional group is obtained by copolymerizing a fluorine-containing monomer and a monomer having a crosslinkable functional group, or by copolymerizing a fluorine-containing monomer and a monomer having a functional group, and then in the polymer. It can be obtained by adding a compound having a crosslinkable functional group to the functional group.

  Fluoroolefins such as fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole; biscoat 6FM (Osaka Organic) Chemical), M-2020 (manufactured by Daikin), (meth) acrylic acid partial or fully fluorinated alkyl ester derivatives, fully or partially fluorinated vinyl ethers, and the like.

  Monomers having a crosslinkable functional group or compounds having a crosslinkable functional group include monomers having a glycidyl group such as glycidyl acrylate and glycidyl methacrylate; monomers having a carboxyl group such as acrylic acid and methacrylic acid; hydroxyalkyl acrylate and hydroxyalkyl Monomers having a hydroxyl group such as methacrylate; methylol acrylate, methylol methacrylate; monomers having a vinyl group such as allyl acrylate and allyl methacrylate; monomers having an amino group; monomers having a sulfonic acid group;

  As a material for forming the low refractive index layer, a material containing a sol in which fine particles such as silica, alumina, titania, zirconia, magnesium fluoride and the like are dispersed in an alcohol solvent is used because it can improve scratch resistance. Can do. From the viewpoint of antireflection properties, the fine particles preferably have a lower refractive index. Such fine particles may have voids, and silica hollow fine particles are particularly preferable. The average particle size of the hollow fine particles is preferably 5 nm to 2000 nm, and more preferably 20 nm to 100 nm. Here, the average particle diameter is a number average particle diameter obtained by observation with a transmission electron microscope.

(Anti-fouling layer)
The antifouling layer is a layer that can impart water repellency, oil repellency, sweat resistance, antifouling properties, and the like. As a material used for forming the antifouling layer, a fluorine-containing organic compound is suitable. Examples of the fluorine-containing organic compound include fluorocarbon, perfluorosilane, and polymer compounds thereof. As a method for forming the antifouling layer, a physical vapor deposition method such as vapor deposition or sputtering, a chemical vapor deposition method, a wet coating method, or the like can be used depending on the material to be formed. The average thickness of the antifouling layer is preferably 1 nm to 50 nm, more preferably 3 nm to 35 nm.

  Further, the polarizer protective film may be provided with other layers such as an antiglare layer, a gas barrier layer, a transparent antistatic layer, a primer layer, an electromagnetic shielding layer, and an undercoat layer.

  When the functional layer as described above is formed, it is preferable to perform chemical treatment on the surface to be formed. Examples of the chemical treatment include corona discharge treatment, sputtering treatment, low-pressure UV irradiation treatment, and plasma treatment. In addition to the chemical treatment, the polarizer protective film of the present invention is subjected to mechanical treatment such as etching, sandblasting, embossing roll, etc. for the purpose of enhancing adhesion to the functional layer and imparting antiglare properties. May be. There is no particular limitation on the method for forming these functional layers, and a general method may be employed for forming each functional layer.

  When the polarizing plate of the present invention is formed by laminating the polarizer protective film of the present invention on one side of the polarizer and laminating another polarizer protective film on the other side, the present invention is usually Are attached to the liquid crystal cell so that the other polarizer protective film is arranged on the inner side (liquid crystal cell side).

(Liquid crystal cell side polarizer protective film)
As the resin constituting the liquid crystal cell side polarizer protective film, polycarbonate resin, polyethersulfone resin, polyethylene terephthalate resin, polyimide resin, polymethyl methacrylate resin, polysulfone resin, polyarylate resin, polyethylene resin, polystyrene resin, polyvinyl chloride Examples thereof include resins, cellulose esters, and alicyclic olefin polymers. Examples of the alicyclic olefin polymer include cyclic olefin random multi-component copolymers described in JP-A No. 05-310845 or US Pat. No. 5,179,171, JP-A No. 05-97978 or US Pat. No. 5,202,388. Examples thereof include the hydrogenated polymers described, thermoplastic dicyclopentadiene ring-opening polymers described in JP-A No. 11-124429 (WO 99/20676), and hydrogenated products thereof. .

  There is no particular limitation on the method of laminating the liquid crystal cell side polarizer protective film on the polarizer, for example, a general method of laminating the liquid crystal cell side polarizer protective film with the polarizer through an adhesive or the like as necessary. Can be adopted. As an adhesive for bonding the liquid crystal cell-side polarizer protective film to the polarizer, the above-mentioned active energy ray-curable adhesive may be used, or a conventionally known adhesive may be used.

  The liquid crystal cell-side polarizer protective film is preferably formed of a material having a light transmittance in the visible region of 400 to 700 nm at a thickness of 1 mm of 80% or more, more preferably 85% or more, and even more preferably 90% or more. is there.

  The polarizing plate of the present invention is obtained by laminating a film showing birefringence on the liquid crystal cell side polarizer protective film side in addition to the polarizer protective film, polarizer, and liquid crystal cell side polarizer protective film of the present invention. There may be. In this case, the liquid crystal cell side is preferably optically isotropic. Specifically, Re is preferably 20 nm or less, more preferably 10 nm or less. The absolute value of Rth is preferably 30 nm or less, more preferably 20 nm or less. The retardation Re in the in-plane direction and the retardation Rth in the thickness direction are Re = (nx−ny) × d, Rth = ((nx + ny) / when the thickness of the film is d (nm). 2-nz) × d. nx and ny are in-plane main refractive indexes (nx ≧ ny); nz is a refractive index in the thickness direction; and d is an average thickness.

  Birefringent films include those obtained by stretching a film containing a thermoplastic resin, those obtained by forming an optically anisotropic layer on an unstretched thermoplastic resin film, and optical on a film containing a thermoplastic resin. After forming the anisotropic layer, it can be further stretched. The film showing birefringence may be a single layer film or a laminated film.

  Moreover, you may use the film which shows the above birefringence as a liquid crystal cell side polarizer protective film. When a birefringent film is used as a liquid crystal cell-side polarizer protective film, or when a birefringent film is laminated on the liquid crystal cell-side polarizer protective film, color compensation, viewing angle compensation, etc. With the optical compensation function, the visibility of the liquid crystal display device is improved.

  In addition, the polarizing plate of the present invention preferably exhibits a hardness of “3H” or more in a pencil hardness test (test plate is a glass plate) shown in JIS K5600-5-4, and more preferably exhibits a hardness of “4H” or more. preferable.

<Liquid crystal display device>
The liquid crystal display device of the present invention can be manufactured by combining the polarizing plate of the present invention and the liquid crystal cell. In this liquid crystal display device, typically, a light source, an incident side polarizing plate, a liquid crystal cell, and an outgoing side polarizing plate are arranged in this order. The polarizing plate of the present invention is preferably provided at least on the emission side of the apparatus. The liquid crystal display device of the present invention may further include a retardation plate, a brightness enhancement film, a light guide plate, a light diffusion plate, a light diffusion sheet, a light collection sheet, a reflection plate, and the like.

  EXAMPLES Hereinafter, an Example and a comparative example are shown and this invention is demonstrated in detail. Parts and% are based on mass unless otherwise specified.

(Acrylic resin)
As the acrylic resin, a copolymer of methyl methacrylate / methyl acrylate = 96% / 4% was used.

(Acrylic elastic polymer A)
As the acrylic elastic polymer particles A, the inner layer is composed mainly of butyl acrylate, polymerized with styrene and a small amount of allyl methacrylate, and the soft elastic body, the outer layer is methyl methacrylate with a small amount of ethyl acrylate. A two-layered elastic particle made of a hard polymer polymerized using a polymer having a number average particle diameter of 75 nm.

(Acrylic elastic polymer B)
As the acrylic elastic polymer particles B, the innermost layer is a hard polymer obtained by polymerizing methyl methacrylate with a small amount of allyl methacrylate, the intermediate layer is mainly composed of butyl acrylate, and styrene and a small amount of A soft elastic body polymerized using allyl methacrylate, the outermost layer is an elastic particle having a three-layer structure made of a hard polymer obtained by polymerizing methyl methacrylate with a small amount of ethyl acrylate, An elastic body having a number average particle diameter of 240 nm was used.

(Production of polarizer)
A 75 μm-thick polyvinyl alcohol-based resin film (average polymerization degree: 1700, saponification degree: 99.9 mol% or more) was uniaxially stretched at a draw ratio of 5 times, and while maintaining the tension state, iodine and potassium iodide Was immersed in an aqueous solution containing iodine (iodine: potassium iodide: water = 0.05: 5: 100 (weight ratio)) for 60 seconds. Next, it was immersed in a 65 ° C. aqueous solution containing potassium iodide and boric acid (potassium iodide: boric acid: water = 2.5: 7.5: 100 (weight ratio)) for 300 seconds. After washing with pure water at 25 ° C. for 20 seconds, it was dried at 50 ° C. to obtain a polarizer formed of a polyvinyl alcohol resin.

Examples 1-3, Comparative Examples 1-3
(Preparation of polarizer protective film)
Acrylic resin pellets and acrylic elastic polymer particles A or B were melt-kneaded at the ratios shown in Table 1 to obtain acrylic resin composition pellets (Examples 1 to 3, Comparative Examples 1 and 2). . Acrylic resin composition pellets (Examples 1 to 3, Comparative Examples 1 and 2) or acrylic resin pellets (Comparative Example 3) were introduced into a 65 mmφ single screw extruder, and a T-die having a set temperature of 275 ° C. Then, both sides of the extruded film were cooled so that they were completely in contact with the polishing roll (metal roll). Thus, an 80 μm-thick polarizer protective film made of an acrylic resin was obtained. The thickness of the polarizer protective film was measured using a digital length measuring device “MH-15M” manufactured by Nikon Corporation.

(Preparation of polarizing plate)
A polarizer protective film is bonded to both sides of the polarizer via a photocationic polymerization type epoxy adhesive or a photo radical polymerization type acrylic adhesive, and the polarizing plate is irradiated with ultraviolet rays having an integrated light quantity of 3000 mJ / cm ^2. Got.

(Adhesive evaluation)
The obtained polarizing plate was allowed to stand at room temperature for 1 hour, and then a cutter blade was inserted between the polarizer and the protective film, and how the blade entered when trying to push the blade forward was evaluated according to the following criteria.

○: The cutter blade does not enter between the polarizer and the protective film.
X: The cutter blade enters between the polarizer and the protective film.

Claims (8)

  A single-layer or multi-layer polarizer protective film having a layer of a thermoplastic resin composition containing 55 to 75 parts by weight of a thermoplastic resin and 25 to 45 parts by weight of an elastic particle, wherein the elastic body in the elastic particle The polarizer protective film characterized by having a number average particle size of 10 to 120 nm.   The polarizer protective film according to claim 1, wherein the thermoplastic resin is an acrylic resin.   The polarizer protective film according to claim 1, wherein the elastic particles are particles containing an acrylic elastic polymer.   4. The polarizer protective film according to claim 3, wherein the elastic particles are particles having a multilayer structure having a polymer layer mainly composed of alkyl methacrylate on the outside of the acrylic elastic polymer.   The polarizer protective film according to claim 1, having an overall thickness of 100 μm or less.   The polarizing plate formed by laminating | stacking the polarizer protective film and polarizer in any one of Claims 1-5 with an adhesive agent.   The polarizing plate according to claim 6, wherein the adhesive is an active energy ray-curable adhesive.   A liquid crystal display device comprising the polarizing plate according to claim 6 and a liquid crystal cell.