JP6520165B2 - Polarizer protective film and polarizing plate - Google Patents

Description

  The present invention relates to a polarizer protective film and a polarizing plate having the polarizer protective film and a polarizer.

  2. Description of the Related Art In recent years, liquid crystal display devices that are light in weight and thin and operate with low power consumption and low voltage are widely used in information display devices such as mobile phones, portable information terminals, monitors for computers, and televisions.

  In the liquid crystal display device, it is essential to arrange a polarizing plate. As the polarizing plate, one is usually used in which a polarizer protective film for protecting a polarizer is disposed on at least one surface of a polarizer in which a dichroic dye is adsorbed and aligned on a polyvinyl alcohol resin film. .

  The polarizer protective film is desired to be excellent in ultraviolet absorptivity in order to prevent the polarizer from being deteriorated by ultraviolet light. Therefore, Patent Document 1 discloses, as a polarizer protective film having an ultraviolet absorptivity, an acrylic resin, a triazine-based ultraviolet absorber, and a triazole-based ultraviolet absorber.

JP 2012-3269 A

  However, in Patent Document 1, although the absorption ability to ultraviolet light having a wavelength of 380 nm is examined, the absorption ability to ultraviolet light having a wavelength shorter than this wavelength is not examined.

  In addition, when the polarizer protective film is disposed on at least one surface of the polarizer to form a polarizing plate, the polarizing plate may appear yellow.

  It is an object of the present invention to provide a polarizer protective film which is excellent in ultraviolet absorptivity and which is hardly visible in yellow when the polarizer is disposed on at least one surface of the polarizer to be a polarizer. It is providing the polarizing plate which has a polarizer protective film and a polarizer.

In order to solve the above-mentioned subject, the present invention provides the following inventions.
<1> A polarizer protective film comprising an ultraviolet absorber A having an absorption maximum at a wavelength of 200 to 300 nm, an ultraviolet absorber B having an absorption maximum at a wavelength of 320 to 400 nm, and a thermoplastic resin, and transmitting light at a wavelength of 260 nm A polarizer protective film characterized in that the ratio is 3% or less, the light transmittance at a wavelength of 380 nm is 5% or less, and the value of b ^* is 0.50 or less.
The polarizer protective film as described in said <1> whose total amount of <2> ultraviolet absorbers A and B is 5 weight part or less with respect to 100 weight part of thermoplastic resins.
The polarizer protective film as described in said <1> or <2> whose weight average molecular weights of <3> ultraviolet absorbers A and B are 500-1000, respectively.
<4> The UV absorber A is at least one member selected from the group consisting of triazine UV absorbers, benzotriazole UV absorbers, benzoate UV absorbers, benzophenone UV absorbers and cyanoacrylate UV absorbers The polarizer protective film in any one of said <1>-<3>.
<5> The UV absorber B is one or more selected from the group consisting of triazine UV absorbers, benzotriazole UV absorbers, benzoate UV absorbers, benzophenone UV absorbers and cyanoacrylate UV absorbers The polarizer protective film in any one of said <1>-<4>.
<6> The thermoplastic resin is an acrylic resin, polycarbonate resin, polyester resin, norbornene resin, cellulose ester resin, cyclic olefin resin, styrene resin, methyl methacrylate-styrene resin, acrylonitrile-styrene resin The polarizer protective film in any one of said <1>-<5> which is 1 or more types chosen from the group which consists of resin and an acrylonitrile butadiene styrene resin.
The polarizing plate in which the polarizer protective film in any one of <7> said <1>-<6> is arrange | positioned at the at least one surface of a polarizer.
The polarizing plate as described in said <7> by which the <8> polarizer protective film and the polarizer are bonded through the adhesive bond layer.
The polarizing plate as described in said <8> which a <9> adhesive-agent layer becomes what is formed from an active energy ray hardening adhesive.
The polarizing plate in any one of said <7>-<9> which a <10> light polarizer becomes a polyvinyl-alcohol-type resin film to which a dichroic dye is adsorbed and oriented.

  According to the present invention, it is possible to provide a polarizer protective film which is excellent in ultraviolet absorptivity and which is hardly visible as yellow when the polarizer is disposed on at least one surface of the polarizer to form a polarizer. Further, according to the present invention, it is possible to provide a polarizing plate which does not easily appear yellow.

The polarizer protective film of the present invention comprises an ultraviolet absorber A having an absorption maximum at a wavelength of 200 to 300 nm, an ultraviolet absorber B having an absorption maximum at a wavelength of 320 to 400 nm, and a thermoplastic resin, and has a light transmittance at a wavelength of 260 nm. Is 3% or less, the light transmittance at a wavelength of 380 nm is 5% or less, and the value of b ^* is 0.50 or less. According to the polarizer protective film of the present invention, in addition to the absorptivity to ultraviolet light of wavelength 380 nm, the absorptivity to ultraviolet light of wavelength 260 nm which is ultraviolet light of a short wavelength is also superior to the ultraviolet light of wavelength 380 nm. When it arrange | positions on at least one surface of, and it is set as a polarizing plate, the said polarizing plate can be made hard to look yellowish.

(Thermoplastic resin)
As the thermoplastic resin, various conventionally known thermoplastic resins can be used. For example, acrylic resin, cyclic olefin resin, styrene resin, methyl methacrylate-styrene resin, acrylonitrile-styrene resin (AS Resin), acrylonitrile-styrene-butadiene resin (ABS resin), cellulose ester resin, polyester resin, polycarbonate resin, polyarylate resin, polysulfone (also including polyether sulfone) resin, polyethylene resin, polypropylene Resin, cellulose diacetate resin, cellulose triacetate resin, cellulose acetate propionate resin, cellulose acetate butyrate resin, polyvinylidene chloride resin, polyvinyl alcohol resin, ethylene vinyl alcohol Fat, syndiotactic polystyrene resin, norbornene resin, polymethyl pentene resins, polyether ketone resins, polyether ketone imide resins, polyamide resins, fluorine resins and nylon resins. Among them, acrylic resins, polycarbonate resins, polyester resins, norbornene resins, cellulose ester resins, methyl methacrylate-styrene resins, AS resins and ABS resins are preferable, and acrylic resins, polycarbonate resins and polyesters Based resins are more preferable, and acrylic resins are particularly preferable because they are excellent in transparency and weather resistance. These thermoplastic resins may be used alone or in combination of two or more.

  As acrylic resin, for example, homopolymer or copolymer of 2 or more types of acrylic monomers such as (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylonitrile and the like, acrylic monomers and other monomers And copolymers thereof. In the present specification, the term "(meth) acrylic" means "acrylic" and / or "methacrylic". As an acrylic resin, a commercial item may be used, for example, Sumitomo Chemical Co., Ltd. "Sumipex EX", "Sumipex MH", etc. are mentioned.

  As an acrylic resin, it is preferable to use a methacrylic resin from the viewpoint of having excellent hardness, weather resistance, transparency and the like. A methacrylic resin is a polymer obtained by polymerizing a monomer consisting mainly of methacrylic acid ester, and, for example, a homopolymer of methacrylic acid ester (polyalkyl methacrylate), 50% by weight or more of methacrylic acid ester and 50 Copolymers with monomers other than methacrylic acid esters of weight% or less, etc. may be mentioned. In the case of the copolymer, preferably 70% by weight or more of methacrylic acid ester and 30% by weight or less of monomers other than methacrylic acid ester, and more preferably 90% by weight of methacrylic acid ester based on the total amount of monomers. % Or more and 10% by weight or less of monomers other than methacrylic acid ester.

  Examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, heptyl methacrylate, 2-ethylhexyl methacrylate, N-octyl methacrylate, n-nonyl methacrylate, isononyl methacrylate, decyl methacrylate, undecyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, lauryl methacrylate, methoxyethyl methacrylate, ethoxyethyl methacrylate and the like Be Among them, methacrylic esters having an alkyl group having 1 to 8 carbon atoms are preferable, and methyl methacrylate is more preferable. The methacrylic acid esters may be used alone or in combination of two or more.

  As monomers other than methacrylic acid ester, for example, acrylic acid ester, unsaturated nitrile, ethylenic unsaturated carboxylic acid hydroxyalkyl ester, ethylenically unsaturated carboxylic acid amide, ethylenically unsaturated acid, ethylenically unsaturated sulfone Acid esters, ethylenically unsaturated alcohols and esters thereof, ethylenically unsaturated ethers, ethylenically unsaturated amines, ethylenically unsaturated silane compounds, aliphatic conjugated dienes, styrenic monomers and the like can be mentioned. Among them, acrylic esters are preferred. The monomers other than methacrylic acid esters may be used alone or in combination of two or more.

  Examples of acrylic esters include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, heptyl acrylate, 2-ethylhexyl acrylate, N-octyl acrylate, n-nonyl acrylate, isononyl acrylate, decyl acrylate, undecyl acrylate, n-amyl acrylate, isoamyl acrylate, lauryl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate etc. Be Among them, acrylic esters having an alkyl group having 1 to 8 carbon atoms are preferable, and methyl acrylate is more preferable.

  Examples of the unsaturated nitrile include acrylonitrile, α-chloroacrylonitrile, α-methoxyacrylonitrile, methacrylonitrile, vinylidene cyanide and the like.

  Examples of the ethylenically unsaturated carboxylic acid hydroxyalkyl ester include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate and the like.

  Examples of the ethylenically unsaturated carboxylic acid amide include acrylamide, methacrylamide, N-butoxymethyl acrylamide, N-butoxymethyl methacrylamide, N-butoxyethyl acrylamide, N-butoxyethyl methacrylamide, N-methoxymethyl acrylamide, N -Methoxymethyl methacrylamide, Nn n-propioxymethyl acrylamide, N n n-propioxymethyl methacrylamide, N-methyl acrylamide, N-methyl methacrylamide, N, N-dimethyl acrylamide, N, N-dimethyl methacrylamide , N, N-diethylacrylamide, N, N-diethylmethacrylamide and the like.

  Ethylenically unsaturated acids include, for example, ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, fumaric anhydride, maleic acid, maleic anhydride, vinylsulfonic acid, isoprene sulfonic acid, Ethylenic unsaturated sulfonic acid etc. are mentioned. The ethylenically unsaturated acid monomer may be neutralized with, for example, an alkali metal such as sodium or potassium, ammonia or the like.

  Examples of ethylenically unsaturated sulfonic acid esters include alkyl vinyl sulfonates and alkyl isoprene sulfonates.

  Ethylenically unsaturated alcohols and esters thereof include, for example, allyl alcohol, methallyl alcohol, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl stearate, vinyl benzoate, allyl acetate, allyl allyl acetate, allyl laurate, benzoate and the like Examples thereof include allyl acid, vinyl alkyl sulfonate, allyl alkyl sulfonate and vinyl aryl sulfonate.

  Examples of the ethylenically unsaturated ether include methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, methyl allyl ether, ethyl allyl ether and the like.

  Examples of the ethylenically unsaturated amines include vinyldimethylamine, vinyldiethylamine, vinyldiphenylamine, allyldimethylamine, methallyldiethylamine and the like.

  Examples of the ethylenically unsaturated silane compound include vinyltriethylsilane, methylvinyldichlorosilane, dimethylallylchlorosilane, vinyltrichlorosilane and the like.

  Examples of aliphatic conjugated dienes include 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-neopentyl-1,3-butadiene, 2-chloro 1,3-Butadiene, 1,2 dichloro-1,3-butadiene, 2,3-dichloro-1,3-butadiene, 2-bromo-1,3-butadiene, 2-cyano-1,3-butadiene, And substituted linear conjugated pentadienes, linear and side chain conjugated hexadienes, and the like.

  Examples of styrene-based monomers include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, ethylstyrene, dimethylstyrene, p-tert-butylstyrene, 2,4-dimethylstyrene, methoxystyrene, Chlorostyrene, bromostyrene, fluorostyrene, nitrostyrene, chloromethylstyrene, vinyltoluene, acetoxystyrene, p-dimethylaminomethylstyrene and the like can be mentioned.

  Moreover, as monomers other than methacrylic acid ester, a polyfunctional monomer may be sufficient. As polyfunctional monomers, for example, polyunsaturated carboxylic acid esters of polyhydric alcohols such as ethylene glycol dimethacrylate, butanediol dimethacrylate, and trimethylolpropane triacrylate, allyl acrylate, allyl methacrylate, allyl cinnamic acid And alkenyl esters of unsaturated carboxylic acids such as: diaryl phthalate, diallyl maleate, triallyl cyanurate, polyalkenyl esters of polybasic acids such as triallyl isocyanurate, aromatic polyalkenyl compounds such as divinyl benzene, etc. .

  Among these acrylic resins, a homopolymer of methyl methacrylate (polymethyl methacrylate), or 50% by weight or more and 99.9% by weight or less of methyl methacrylate and 0.1% by weight or more and 50% by weight or less of methacrylic acid Copolymers with (meth) acrylic esters other than methyl are particularly preferred. A copolymer of 50% by weight to 99.9% by weight of methyl methacrylate and 0.1% by weight to 50% by weight of a (meth) acrylic acid ester other than methyl methacrylate is methyl methacrylate and Methyl methacrylate is contained in a ratio of 50% by weight or more and 99.9% by weight or less based on the total amount 100% by weight with (meth) acrylic acid ester, and (meth) acrylic acid ester other than methyl methacrylate is 0 It is a copolymer obtained by polymerizing a monomer mixture contained in a proportion of 1% by weight or more and 50% by weight or less. In the monomer mixture, methyl methacrylate is preferably contained in a proportion of 70% by weight to 99.9% by weight, and more preferably in a proportion of 90% by weight to 99.9% by weight.

  The acrylic resin is obtained by subjecting the above-mentioned monomers to a polymerization method such as, for example, an emulsion polymerization method, a suspension polymerization method, a bulk polymerization method, a liquid injection polymerization method (cast polymerization method). The polymerization is carried out using light irradiation or a polymerization initiator, and azo initiators (eg, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), etc. It is preferable to use a polymerization initiator such as a peroxide initiator (eg, lauroyl peroxide, benzoyl peroxide), or a redox initiator in which an organic peroxide and an amine are combined. The polymerization initiator is generally 0.01 to 1 part by weight, preferably 0.01 to 0.5 parts by weight, per 100 parts by weight of the monomer constituting the acrylic resin. Used. Furthermore, chain transfer agents for controlling molecular weight (eg, methyl mercaptan, n-butyl mercaptan, linear or branched alkyl mercaptan compounds such as t-butyl mercaptan, etc.), crosslinking agents, etc. may be added.

  In the thermoplastic resin, one or two or more additives such as light diffusing agents, matting agents, dyes, light stabilizers, antioxidants, mold release agents, flame retardants, antistatic agents, etc., as necessary. You may contain more than species. When the additive is contained, its content is preferably 0.005% by weight or more and 30% by weight or less based on the total amount of the thermoplastic resin.

  Rubber particles may be added to the thermoplastic resin, and it is preferable to add rubber particles particularly when using an acrylic resin as the thermoplastic resin. Here, as the rubber particles, for example, acrylic rubber particles, butadiene rubber particles, styrene-butadiene rubber particles and the like can be used, but among them, from the viewpoint of weather resistance and durability, acrylic rubber Particles are preferably used. The rubber particles may be used alone or in combination of two or more different in composition or average particle diameter.

  The acrylic rubber particles are particles containing an elastic polymer mainly composed of acrylic ester as a rubber component, and may be particles of a single layer structure consisting only of this elastic polymer, or of this elastic polymer. The particles may have a multilayer structure having a layer and, for example, a polymer layer mainly composed of methacrylic acid ester, but are preferably particles having a multilayer structure from the viewpoint of the surface hardness of the polarizer protective film. Further, the elastic polymer may be a homopolymer of acrylic acid ester, or a copolymer of 50% by weight or more of acrylic acid ester and 50% by weight or less of other monomers. . Here, an alkyl ester of acrylic acid is usually used as the acrylic ester.

  The preferred monomer composition of the elastic polymer mainly composed of acrylic acid ester is 50% by weight or more and 99.9% by weight or less of alkyl acrylate and 0% by weight or more of alkyl methacrylate based on all monomers. .9% by weight or less, 0 to 49.9% by weight of monofunctional monomers other than these, and 0.1% to 10% by weight or less of polyfunctional monomers.

  Here, as the alkyl acrylate in the above-mentioned elastic polymer, for example, it is the same as that contained in the example of the acrylic ester mentioned above as the monomer component of the methacrylic resin, and the carbon number of the alkyl group is usually It is 1 to 8, preferably 4 to 8. The alkyl methacrylate in the above-mentioned elastic polymer is, for example, the same as that contained in the example of the methacrylic acid ester mentioned above as the monomer component of the methacrylic resin, and the carbon number of the alkyl group is usually 1 To 8, preferably 1 to 4.

  As monofunctional monomers other than alkyl acrylate and alkyl methacrylate in the above-mentioned elastic polymer, for example, monofunctional monomers other than alkyl methacrylate and alkyl acrylate which are listed above as monomer components of methacrylic resin Similar to the example of. Among them, styrenic monomers are preferably used.

  Examples of the polyfunctional monomer in the above-mentioned elastic polymer are the same as the examples of the polyfunctional monomer mentioned above as the monomer component of the methacrylic resin, and among them, alkenyl ester of unsaturated carboxylic acid, Polyalkenyl esters of polybasic acids are preferably used.

  As the alkyl acrylate, the alkyl methacrylate, the monofunctional monomer other than these, and the polyfunctional monomer in the above-mentioned elastic polymer, two or more of them may be used as needed.

  When a multi-layered structure is used as the acrylic rubber particle, as a preferable example thereof, a layer of a polymer mainly composed of methacrylic acid ester on the outside of the layer of the above-mentioned elastic polymer mainly composed of acrylic acid ester And the above-mentioned elastic polymer mainly composed of acrylic acid ester as an inner layer, and an outer layer composed of a polymer mainly composed of methacrylic acid ester as an outer layer. Here, as methacrylic acid ester which is a monomer component of the polymer of the outer layer, alkyl methacrylate is usually used. The polymer of the outer layer is generally formed in a ratio of 10 parts by weight to 400 parts by weight, preferably 20 parts by weight to 200 parts by weight with respect to 100 parts by weight of the elastic polymer of the inner layer. By setting the polymer of the outer layer to 10 parts by weight or more with respect to 100 parts by weight of the elastic polymer of the inner layer, the aggregation of the elastic polymer becomes difficult to occur.

  The preferred monomer composition of the polymer of the outer layer is 50% by weight or more and 100% by weight or less of alkyl methacrylate, and 0% by weight or more and 50% by weight or less of alkyl acrylate, based on all monomers. The content of the monomer is 0% to 50% by weight, and the content of the polyfunctional monomer is 0% to 10% by weight.

  The alkyl methacrylate in the polymer of the outer layer is, for example, the same as that contained in the example of the methacrylic acid ester mentioned above as the monomer component of the methacrylic resin, and the carbon number of the alkyl group is usually 1 to 8, preferably 1 to 4. Among them, methyl methacrylate is preferably used.

  The alkyl acrylate in the polymer of the outer layer is, for example, the same as that contained in the example of the acrylic ester mentioned above as the monomer component of the methacrylic resin, and the carbon number of the alkyl group is usually 1 to 8, preferably 1 to 4.

  Examples of monomers other than alkyl methacrylate and alkyl acrylate in the polymer of the outer layer include, for example, monofunctional monomers other than methacrylic acid esters and acrylic acid esters listed above as monomer components of methacrylic resin. It is the same as that of the example, and as the polyfunctional monomer, for example, it is the same as the example of the polyfunctional monomer described above as the monomer component of the methacrylic resin.

  The alkyl methacrylate, the alkyl acrylate, the monomer other than these, and the polyfunctional monomer in the polymer of the outer layer may be used alone or in combination of two or more as needed.

  In addition, as a preferable example of the acrylic rubber particles having a multilayer structure, a weight based on methacrylic acid ester as the main component of the above-mentioned elastic polymer mainly composed of acrylic ester which is an inner layer of the above-mentioned two-layer structure A polymer having a united layer, that is, a polymer mainly composed of methacrylic acid ester as an inner layer, an elastic polymer mainly composed of the above-mentioned acrylic acid ester as an intermediate layer, and a weight mainly composed of the above methacrylic acid ester Mention may also be made of at least a three-layer structure in which the coalescence is the outer layer. Here, as methacrylic acid ester which is a monomer component of a polymer of an inner layer, alkyl methacrylate is usually used. The inner layer polymer is generally formed in a ratio of 10 parts by weight to 400 parts by weight, preferably 20 parts by weight to 200 parts by weight with respect to 100 parts by weight of the intermediate layer elastic polymer.

  The preferred monomer composition of the polymer of the inner layer is 70% by weight or more and 100% by weight or less of alkyl methacrylate, and 0% by weight or more and 30% by weight or less of alkyl acrylate, based on all monomers. The content of the monomer is 0% to 30% by weight, and the content of the polyfunctional monomer is 0% to 10% by weight.

  The alkyl methacrylate in the polymer of the inner layer is, for example, the same as that contained in the example of the methacrylic acid ester mentioned above as the monomer component of the methacrylic resin, and the carbon number of the alkyl group is usually 1 to 8, preferably 1 to 4. Among them, methyl methacrylate is preferably used. The alkyl acrylate in the polymer of the inner layer is, for example, the same as that contained in the example of the acrylic ester mentioned above as the monomer component of the methacrylic resin, and the carbon number of the alkyl group is usually It is 1 to 8, preferably 1 to 4.

  Examples of monomers other than alkyl methacrylate and alkyl acrylate in the polymer of the inner layer include, for example, monofunctional monomers other than methacrylic acid esters and acrylic acid esters listed above as monomer components of methacrylic resin. Examples of the polyfunctional monomer are the same as the examples, and examples of the polyfunctional monomer are the same as the examples of the polyfunctional monomer described above as the monomer component of the methacrylic resin.

  The alkyl methacrylate, the alkyl acrylate, the monomer other than these, and the polyfunctional monomer in the polymer of the inner layer may be used alone or in combination of two or more as needed.

The acrylic rubber particles can be prepared by polymerizing the monomer component of the above-mentioned elastic polymer mainly composed of acrylic acid ester by at least one-step reaction by an emulsion polymerization method or the like. At that time, as described above, in the case of forming a polymer layer mainly composed of methacrylic acid ester on the outside of the above-mentioned elastic polymer layer, the monomer component of the polymer of this outer layer is What is necessary is just to make it graft | graft to the said elastic polymer by superposing | polymerizing by reaction of an at least 1 step by the emulsion polymerization method etc. in presence of a polymer.
Further, as described above, in the case of forming a polymer layer mainly composed of methacrylic acid ester on the inner side of the above-mentioned elastic polymer layer, first, the monomer component of the polymer of the inner layer is The monomer component of the above elastic polymer is polymerized by at least one reaction by an emulsion polymerization method or the like, in the presence of the resulting polymer, and then polymerized by an emulsion polymerization method or the like. By grafting to the polymer of the inner layer, and further polymerizing the monomer component of the polymer of the outer layer by at least one reaction by an emulsion polymerization method or the like in the presence of the obtained elastic polymer. By grafting, the above elastic polymer may be grafted. When each layer is polymerized in two or more stages, the overall monomer composition may be within a predetermined range, not the monomer composition of each stage.

  With respect to the particle diameter of the acrylic rubber particles, the average particle diameter of the layer of the elastic polymer mainly composed of acrylic ester in the rubber particles is preferably 0.01 μm or more and 0.4 μm or less, and 0.05 μm The thickness is more preferably 0.3 μm or less and still more preferably 0.07 μm or more and 0.25 μm or less. When the average particle size of the elastic polymer layer is larger than 0.4 μm, the transparency of the polarizer protective film may be reduced. When the average particle diameter of the elastic polymer layer is smaller than 0.01 μm, the surface hardness of the polarizer protective film may be lowered.

The above average particle diameter is obtained by mixing acrylic rubber particles with methacrylic resin to form a film, staining the layer of the above-mentioned elastic polymer with ruthenium oxide in the cross section thereof, and observing the portion with an electron microscope to obtain a dyed portion. It can be determined from the diameter of
That is, when acrylic rubber particles are mixed with methacrylic resin and the cross section is dyed with ruthenium oxide, the methacrylic resin of the mother phase is not dyed, and a polymer mainly composed of methacrylic acid ester on the outside of the layer of the elastic polymer In the presence of the layer, the polymer of this outer layer is not dyed, but only the layer of the elastic polymer is dyed, and thus, the dyed part from the diameter of the portion observed in a substantially circular shape by the electron microscope, The particle size can be determined. When a layer of a polymer mainly composed of a methacrylic acid ester is present inside the layer of the elastic polymer, the polymer of the inner layer is not dyed, and the layer of the elastic polymer on the outer side is dyed 2 Although it will be observed in the state of the layer structure, in this case, it may be considered from the outside of the two-layer structure, that is, the outer diameter of the layer of the elastic polymer.

  The content ratio of the rubber particles to the thermoplastic resin is preferably 40% by weight or less, more preferably 30% by weight or less, when the total amount of the thermoplastic resin and the rubber particles is 100% by weight. If the content of the rubber particles is greater than 40% by weight of the entire acrylic resin, the surface hardness of the polarizer protective film may be reduced.

(UV absorbers A and B)
As the UV absorber A, various UV absorbers known in the prior art can be used as long as the UV absorber has an absorption maximum at a wavelength of 200 to 300 nm. For example, triazine based UV absorbers, benzophenone based UV absorbers And benzotriazole-based ultraviolet absorbers, benzoate-based ultraviolet absorbers, cyanoacrylate-based ultraviolet absorbers, and the like. These ultraviolet absorbers may be used alone or in combination of two or more.

  As the UV absorber B, various UV absorbers known in the prior art can be used as long as the UV absorber has an absorption maximum at a wavelength of 320 to 400 nm. For example, triazine based UV absorbers and benzophenone based UV absorbers And benzotriazole-based ultraviolet absorbers, benzoate-based ultraviolet absorbers, cyanoacrylate-based ultraviolet absorbers, and the like. These ultraviolet absorbers may be used alone or in combination of two or more.

  As a triazine type ultraviolet absorber, for example, 2,4-diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy- 4-ethoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-propoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-) 4-butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- ( 2-hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-octyloxyphenyl) -1,3,5- Liazine, 2,4-diphenyl-6- (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-benzyloxyphenyl)- 1,3,5-triazine etc. are mentioned

  Examples of benzophenone-based UV absorbers include 2,4-dihydroxy-benzophenone, 2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4-n-octoxy-benzophenone, 2-hydroxy-4-dodecyloxy-benzophenone, and the like. 2-hydroxy-4-octadecyloxy-benzophenone, 2,2'-dihydroxy-4-methoxy-benzophenone, 2,2'-dihydroxy-4,4'-dimethoxy-benzophenone, 2,2 ', 4,4' -Tetrahydroxy- benzophenone etc. are mentioned.

  As a benzotriazole type ultraviolet absorber, for example, 2- (2'-hydroxy-5-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) benzotriazole , 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-) 3 ', 5'-Di-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3') , 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 '-(3 ", 4", 5 ") 6 ′ ′-tetrahydrophthalimidomethyl) -5′-methylphenyl) benzotriazole, 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 (2'-hydroxy-3 ', 5'-di-tert-butyl) Phenyl) -5-chlorobenzotriazole, (2 (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl) -5-chlorobenzotriazole, 2 (2′-hydroxy-3 ′, 5′- Di-tert-butylphenyl) -5-chlorobenzotriazole, (2 (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl)- - such as chloro benzotriazole.

  Examples of benzoate-based UV absorbers include 2,4-di-t-butylphenyl-3 ′, 5′-di-t-butyl-4′-hydroxybenzoate, 2,6-di-t-butylphenyl- 3 ', 5'-di-t-butyl-4'-hydroxybenzoate, n-hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate and n-octadecyl-3,5-di-t-butyl -4-hydroxy benzoate and the like.

  As a cyanoacrylate type ultraviolet absorber, for example, 2'-ethylhexyl 2-cyano-3,3-diphenyl acrylate, ethyl 2-cyano-3- (3 ', 4'-methylenedioxyphenyl) -acrylate and the like Can be mentioned.

  Commercially available products may be used as the UV absorbers A and B. For example, as triazine-based UV absorbers, “Kemisorb 102” manufactured by Chemipro Chemical Industries, Ltd., “Adecastab LAF 70” manufactured by ADEKA Inc., benzotriazole As a system ultraviolet absorber, "ADEKA STAB LA31" made from ADEKA Corporation etc. is mentioned.

  The combination of the ultraviolet absorbers A and B is not particularly limited as long as it is a combination of an ultraviolet absorber having an absorption maximum at a wavelength of 200 to 300 nm and an ultraviolet absorber having an absorption maximum at a wavelength of 320 to 400 nm A combination of UV absorbers in which the wavelength of the absorption maximum is within a predetermined range, or a combination of UV absorbers of different types wherein the wavelength of the absorption maximum is within a predetermined range It may be For example, in the former case, the UV absorber A is a triazine UV absorber having an absorption maximum at a wavelength of 200 to 300 nm, and the UV absorber B is a triazine UV absorber having an absorption maximum at a wavelength of 320 to 400 nm. And combinations thereof. In the latter case, the ultraviolet absorber A is a triazine-based ultraviolet absorber having an absorption maximum at a wavelength of 200 to 300 nm, and the ultraviolet absorber B is a benzotriazole-type ultraviolet absorber having an absorption maximum at a wavelength of 320 to 400 nm. Some combinations may be mentioned.

  Moreover, 1 type or 2 types or more may be sufficient as ultraviolet absorber A and B, respectively. Some UV absorbers are particularly excellent in UV absorptivity, but some tend to make the polarizing plate look yellowish, and some UV absorbers are not particularly good, but the polarizer is less likely to look yellow and therefore have excellent UV absorptivity, And, in order to obtain a polarizer protective film in which the polarizing plate hardly appears yellow, it is preferable to appropriately combine ultraviolet absorbers having different performances. For example, although only one type is used as the ultraviolet absorber A and the ultraviolet absorber B is particularly excellent in ultraviolet absorptivity, those in which the polarizing plate tends to look yellowish and those in which the ultraviolet absorptivity is not particularly excellent In addition, it may be used in combination with ones that are difficult to look yellow. As described above, although the ultraviolet absorptivity is particularly excellent, the polarizing plate tends to look yellowish and the ultraviolet absorptivity is not particularly excellent, but the polarizer protective film can be used in combination with the one in which the polarizing plate hardly looks yellowish When it is excellent in ultraviolet absorptivity, and it arrange | positions on at least one surface of a polarizer and it is set as a polarizing plate, it is preferable from the point which makes the said polarizing plate difficult to look yellowish. In addition, although it illustrated about the case where 2 types of ultraviolet absorbers B are used together here, it is preferable from the same point also about the case where 2 types of ultraviolet absorbers A are used together.

  The weight average molecular weight of each of the UV absorbers A and B is preferably 500 to 1000, and more preferably 550 to 700. If the weight average molecular weight of the ultraviolet absorbers A and B is too small, smoke is likely to be generated during formation of the polarizer protective film, and if the weight average molecular weight is too large, the compatibility with the thermoplastic resin tends to be reduced.

  The UV light absorbers A and B preferably have a molar absorption coefficient of 10 L / mol · cm or more at the wavelength of the absorption maximum, and more preferably 15 L / mol · cm or more. When the molar absorption coefficient at the wavelength of the absorption maximum of the ultraviolet absorbers A and B is within the above-mentioned predetermined range, respectively, the ultraviolet absorptivity of the polarizer protective film becomes more excellent, and further, to the polarizer protective film The content of the ultraviolet absorber can be reduced.

(Polarizer protective film)
The polarizer protective film contains the ultraviolet absorber A, the ultraviolet absorber B and the thermoplastic resin described above, and further contains other components as necessary. The polarizer protective film is excellent in ultraviolet absorptivity by containing the ultraviolet absorbers A and B. Examples of other components include rubber particles, antioxidants, lubricants, organic dyes, inorganic dyes, pigments, antistatic agents, surfactants and the like.

  The polarizer protective film has a light transmittance of 3% or less at a wavelength of 260 nm and a light transmittance of 5% or less at a wavelength of 380 nm. The polarizer protective film is excellent in ultraviolet absorptivity, as the light transmittance at a wavelength of 260 nm and a wavelength of 380 nm is 3% or less and 5% or less, respectively. The light transmittance at a wavelength of 260 nm is preferably 2% or less, and the light transmittance at a wavelength of 380 nm is preferably 4% or less. In order to set the light transmittance at the wavelength of 260 nm and the wavelength of 380 nm to the predetermined range, for example, for the light transmittance at the wavelength of 260 nm, the ultraviolet absorber A has a large molar absorption coefficient at the wavelength of the absorption maximum A UV absorber may be used, and for the light transmittance at a wavelength of 380 nm, a UV absorber having a large molar absorption coefficient at the wavelength of the absorption maximum may be used as the UV absorber B.

The polarizer protective film has a b ^* value of 0.50 or less. When the polarizer protective film has a value of b ^* of 0.50 or less, when it is disposed on at least one surface of the polarizer to form a polarizing plate, the polarizing plate hardly looks yellowish. b ^* is a coordinate of L ^* a ^* b ^* color system representing the attribute of color perception consisting of hue and saturation, and when this value exceeds 0.50, the polarizer protective film is at least one of the polarizers The polarizing plate disposed on the surface of the image looks yellow. The value of b ^* is preferably −0.50 or more. When the value of b ^* is smaller than -0.50, a polarizing plate formed by disposing a polarizer protective film on at least one surface of the polarizer may appear blue. The value of b ^* is preferably in the range of −0.50 or more and 0.50 or less from the viewpoint of making the polarizing plate less likely to appear yellow and blue. In order to set the value of b ^{* in} a predetermined range, for example, an ultraviolet absorber having absorption in the visible wavelength range may be used as the ultraviolet absorber A and / or the ultraviolet absorber B so as to correct the hue. .

  The content of the ultraviolet light absorber in the polarizer protective film is preferably 5 parts by weight or less with respect to 100 parts by weight of the thermoplastic resin from the viewpoint of suppressing smoke generation during molding of the polarizer protective film, and 3 parts by weight It is more preferable that it is less than 1 part.

  10-500 micrometers is preferable, 10-300 micrometers is more preferable, 10-100 micrometers is more preferable, and, as for the thickness of a polarizer protective film, 10-40 micrometers is especially preferable. When it becomes too thin, it becomes difficult to maintain the shape against shrinkage of the polarizer as a polarizer protective film, and when it becomes too thick, it becomes heavy and difficult to handle.

The polarizer protective film contains the ultraviolet absorber A, the ultraviolet absorber B and the thermoplastic resin, and if the light transmittance at a specific wavelength and the value of b ^* are respectively in the predetermined ranges, the layer configuration is It is not particularly limited, and may have a single layer configuration or a multilayer configuration. Among them, a single layer configuration is preferable.

  When the layer structure of the polarizer protective film is a multilayer structure, the ultraviolet absorber A, the ultraviolet absorber B and the thermoplastic resin may be all contained in one layer, and the ultraviolet absorber A and the ultraviolet absorber B and B may be contained in different layers. In this multilayer structure, for example, a layer containing a thermoplastic resin on at least one surface of the layer (I) containing the ultraviolet absorber A, the ultraviolet absorber B and the thermoplastic resin, and not containing the ultraviolet absorbers A and B (II) Layered layer, Layer (I) containing UV absorber B and thermoplastic resin, laminated to at least one surface of layer (I) containing UV absorber A and thermoplastic resin, Layer (II) containing at least one of UV absorber A or UV absorber B and thermoplastic resin on at least one surface of layer (I) containing UV absorber A, UV absorber B and thermoplastic resin Layer comprising UV absorber A, UV absorber B and thermoplastic resin, on at least one side of layer (I) containing UV absorber A, UV absorber B and thermoplastic resin (II ) Like stacked configuration thereof. In each layer constitution, when the ultraviolet absorber A, the ultraviolet absorber B or the thermoplastic resin is contained in both of the layer (I) and the layer (II), it is contained in the layer (I) and the layer (II) The ultraviolet absorber A, the ultraviolet absorber B, or the thermoplastic resin may have the same type or content, or may be different. In addition to the layer (I) and the layer (II), another layer may be laminated as the multilayer structure.

  The polarizer protective film may be subjected to surface treatment, and examples of the surface treatment include hard coating treatment, antiglare treatment, antifouling treatment and the like.

  It does not restrict | limit especially as a method to obtain a polarizer protective film, For example, First, the resin composition containing the ultraviolet absorber A, the ultraviolet absorber B, and a thermoplastic resin is obtained, and then this resin composition is melted Examples thereof include extrusion molding, solution casting film forming, and heat pressing. Among them, the melt extrusion method is preferred.

  As the melt extrusion method, for example, first, the ultraviolet absorber A, the ultraviolet absorber B and the thermoplastic resin are mixed, and if necessary, the above-mentioned other components are further mixed to obtain a resin composition. Then, the obtained resin composition is melt-kneaded by a single- or twin-screw extruder, and the molten resin is continuously extruded from the T die into a film, and further, the film continuously extruded from the T die The polarizer protective film is obtained by sandwiching the molten resin in the shape of a pair between a pair of smooth metal rolls made of metal and molding and cooling. In addition, mixing of the ultraviolet absorber A, the ultraviolet absorber B, the thermoplastic resin, and the other components as needed is not particularly limited, and any known method may be used, and a super mixer or a Banbury mixer may be used. It may be melt-kneaded with a single screw or twin screw extruder, or may be combined.

  When the polarizer protective film has the above-described multilayer constitution, for example, a plurality of uniaxial or biaxial extruders are used to constitute the layer (I) and the resin composition constituting the layer (I) After melt-kneading each with the resin composition, the method of laminating through a feed block die, a multi manifold die, etc., etc. are mentioned.

  The polarizer protective film may be stretched by longitudinal stretching and / or transverse stretching. The polarizer protective film is stretched by longitudinal stretching and / or transverse stretching, so that the mechanical strength is excellent and productivity and handleability are improved. In the present specification, stretching of the unstretched film in the machine flow direction means longitudinal stretching, and stretching of the unstretched film in the direction orthogonal to the machine flow direction means transverse stretching.

  The stretching may be uniaxial stretching, but is preferably sequential stretching or simultaneous biaxial stretching. The stretch ratio is preferably 1.1 to 3.0.

  10-500 micrometers is preferable, 10-300 micrometers is more preferable, 10-100 micrometers is more preferable, and, as for the thickness of a stretched film, 10-40 micrometers is especially preferable. If it is too thin, the strength and rigidity will be lost and handling during production will be difficult, and if it is too thick, film winding will be difficult and the line speed and productivity will be significantly degraded.

  The polarizer protective film is not limited to the use for polarizer protection, for example, architectural lighting members such as windows and carport roof materials, vehicular lighting members such as windows, agricultural lighting members such as greenhouses, illumination members, front surfaces It can be used by laminating on a display member such as a filter, etc. Moreover, as a decorative film, a housing of a home appliance, a vehicle interior member, a building material for interior, a wallpaper, a decorative board, an entrance door, a window frame, a drawstring etc. It can also be laminated and used.

(Polarizer)
A polarizer protective film can be disposed on at least one surface of the polarizer to form a polarizing plate. It is preferable that the polarizer protective film and the polarizer be bonded.

  A polarizer is a process of uniaxially stretching a polyvinyl alcohol-based resin film according to a known method, a process of adsorbing the dichroic dye by dyeing the polyvinyl alcohol-based resin film with a dichroic dye, a dichroic dye It can be manufactured through a process of treating the adsorbed polyvinyl alcohol resin film with an aqueous solution of boric acid and a process of washing with water after the treatment with an aqueous solution of boric acid. The polarizer thus obtained has an absorption axis in the uniaxially stretched direction.

  As polyvinyl alcohol-type resin, what saponified polyvinyl acetate type resin can be used. Examples of polyvinyl acetate resins include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

  The degree of saponification of the polyvinyl alcohol-based resin is preferably 85 to 100 mol%, and more preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal modified with aldehydes, polyvinyl acetal and the like can also be used. Moreover, it is preferable that it is 1000-10000, and, as for the polymerization degree of polyvinyl alcohol-type resin, it is more preferable that it is 1500-5000.

  What formed such a polyvinyl alcohol-type resin into a film is used as a raw film of polarizer. The method of forming a polyvinyl alcohol-based resin into a film is not particularly limited, and a known method is adopted. The thickness of the polyvinyl alcohol-based raw film is preferably 10 to 150 μm.

  The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before, simultaneously with, or after the dyeing with the dichroic dye. If uniaxial stretching is performed after dyeing, this uniaxial stretching may be performed before or during the boric acid treatment. Moreover, uniaxial stretching can also be performed in these several steps.

  Uniaxial stretching may be performed by passing between spaced rolls having different peripheral speeds, or may be performed by sandwiching with a heat roll. The uniaxial stretching may be dry stretching in which stretching is performed in the atmosphere, or wet stretching in which a polyvinyl alcohol resin film is swollen using a solvent such as water or an organic solvent. May be The stretching ratio is preferably 3 to 8 times.

  The dyeing with a dichroic dye of a polyvinyl alcohol-based resin film can be performed, for example, by a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic dye. As the dichroic dye, iodine or a dichroic organic dye is used. The polyvinyl alcohol-based resin film is preferably subjected to immersion treatment in water prior to the dyeing treatment.

  When using iodine as a dichroic dye, the method of immersing and dye | staining a polyvinyl-alcohol-type resin film the aqueous solution containing an iodine and potassium iodide is employ | adopted normally. The content of iodine in this aqueous solution is preferably 0.01 to 1 part by weight per 100 parts by weight of water, and the content of potassium iodide is 0.5 to 20 parts by weight per 100 parts by weight of water. Is preferred. It is preferable that the temperature of the aqueous solution used for dyeing | staining is 20-40 degreeC. Moreover, it is preferable that the immersion time (staining time) to this aqueous solution is 20 to 1800 second.

  On the other hand, when using a dichroic organic dye as a dichroic dye, the method of immersing and dyeing a polyvinyl alcohol-type resin film in the aqueous solution containing a water-soluble dichroic organic dye is employ | adopted normally. The content of the dichroic organic dye in the aqueous solution is preferably 0.0001 to 10 parts by weight, and more preferably 0.001 to 1 parts by weight with respect to 100 parts by weight of water. This aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing assistant. It is preferable that the temperature of the dichroic dye aqueous solution used for dyeing | staining is 20-80 degreeC. Moreover, it is preferable that the immersion time (staining time) to this aqueous solution is 10 to 1800 second.

  The boric acid process after dyeing | staining with a dichroic dye can be performed by the method of immersing the dyed polyvinyl alcohol-type resin film in boric-acid containing aqueous solution. The amount of boric acid in the boric acid-containing aqueous solution is preferably 2 to 15 parts by weight, and more 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 preferably 0.1 to 15 parts by weight, and more 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 preferably 60 to 1200 seconds, more preferably 150 to 600 seconds, and still more preferably 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is preferably 50 ° C. or higher, more preferably 50 to 85 ° C., and still more preferably 60 to 80 ° C.

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

  After washing with water, drying treatment is performed to obtain a polarizer. The drying process can be performed using a hot air dryer or a far infrared heater. The temperature of the drying treatment is preferably 30 to 100 ° C., and more preferably 50 to 80 ° C. The drying time is preferably 60 to 600 seconds, more preferably 120 to 600 seconds.

  By the drying process, the moisture content of the polarizer is reduced to a practical level. The water content is preferably 5 to 20% by weight, and more preferably 8 to 15% by weight. When the moisture content is less than 5% by weight, the flexibility of the polarizer is lost, and the polarizer may be damaged or broken after it is dried. On the other hand, if the water content exceeds 20% by weight, the heat stability of the polarizer may be insufficient.

  It is preferable that the thickness of the polarizer which a dichroic dye carries out adsorption orientation to the polyvinyl alcohol-type resin film obtained in this way is 5-40 micrometers.

  When arrange | positioning a polarizer protective film in one side of a polarizer, you may arrange | position a transparent resin film in the other side. The transparent resin film and the polarizer are preferably bonded to each other as in the case of the polarizer protective film and the polarizer. Examples of the transparent resin film include triacetyl cellulose films, polycarbonate films, polyethylene terephthalate films, acrylic resin films, laminated films of acrylic resins and polycarbonate resins, and olefin resin films.

  The olefin resin is, for example, a resin obtained by polymerizing a chain olefin monomer such as ethylene or propylene, or a cyclic olefin monomer such as norbornene or another cyclopentadiene derivative using a polymerization catalyst.

  As olefin resin obtained from a chain | strand-shaped olefin monomer, polyethylene-type resin and a polypropylene resin are mentioned. Among them, a polypropylene-based resin which is a homopolymer of propylene is preferable. Also preferred is a polypropylene-based copolymer resin composed mainly of propylene and copolymerized with a copolymerizable comonomer in a proportion of preferably 1 to 20% by weight, more preferably 3 to 10% by weight.

  As a comonomer copolymerizable with propylene, ethylene, 1-butene or 1-hexene is preferred. Among them, ethylene is preferably used because it is relatively excellent in transparency and stretchability, and a polypropylene-based copolymer resin obtained by copolymerizing ethylene at a ratio of 1 to 20% by weight, preferably 3 to 10% by weight, preferable. By setting the copolymerization ratio of ethylene to 1% by weight or more, transparency and stretchability are improved. On the other hand, if the proportion exceeds 20% by weight, the melting point of the resin may be lowered, and the heat resistance required for the protective film or the retardation film may be impaired.

  As polypropylene-based resins, commercially available products may be used. For example, “Prime Polypro” manufactured by Prime Polymer Co., Ltd., “Novatec” and “Wintec” manufactured by Japan Polypro Co., Ltd., “ Examples include "Sumitomo Noblen" and "Sun Aroma" manufactured by Sun Aroma Co., Ltd.

  An olefin resin obtained by polymerizing a cyclic olefin monomer is generally also referred to as a cyclic olefin resin, an alicyclic olefin resin, or a norbornene resin. Here, it is called cyclic olefin resin.

  As cyclic olefin resin, for example, resin obtained by ring-opening metathesis polymerization using norbornene or its derivative obtained from Dicyclopentadiene and olefins by Diels-Alder reaction as a monomer and subsequent hydrogenation; dicyclopentadiene , Ring-opening metathesis polymerization using tetracyclododecene obtained by Diels-Alder reaction with olefins or (meth) acrylic acid ester as a monomer as a monomer, and resin obtained by subsequent hydrogenation; norbornene, tetracyclo Resin obtained by ring-opening metathesis copolymerization similarly using dodecene, derivatives thereof or other cyclic olefin monomers, and subsequent hydrogenation; said norbornene, tetracyclododecene And at least one cyclic olefin selected from derivatives thereof, and the like aliphatic or aromatic compound and the addition copolymer are allowed to obtain a resin having a vinyl group.

  As the cyclic olefin resin, commercially available products may be used. For example, “TOPAS” manufactured by TOPAS ADVANCED POLYMERS GmbH, “Arton” manufactured by JSR Corporation, “Zeonor” manufactured by Nippon Zeon Corporation, and “ZEONEX” And “Apple” manufactured by Mitsui Chemicals, Inc.

  It can be set as a transparent resin film by film-forming and film-forming chain | strand-shaped olefin resin or cyclic olefin resin. As a method of film formation, the method similar to the method mentioned above as a method of obtaining a polarizer protective film is employable.

  As the olefin resin film, a commercially available product may be used. For example, in the case of a polypropylene resin film, "FILMAX CPP film" manufactured by FILMAX, "Santox" manufactured by Sun Tox Co., Ltd. Company-made "Toshiro", Toyobo Co., Ltd. "Toyobobo Pyrene Film", Toray Film Processing Co., Ltd. "Torefan", Japan Polyace Co., Ltd. "Nihon Polyace", Futamura Chemical Co. Dazai FC "and the like. Moreover, if it is a cyclic olefin resin film, "Zeonor film" by Nippon Zeon Co., Ltd., "Arton film" by JSR Co., Ltd., etc. are mentioned.

  In the transparent resin film, an optical functional film can be laminated on the surface, or an optical functional layer can be coated. As such an optical functional film and an optical functional layer, an easily bonding layer, a conductive layer, a hard-coat layer etc. are mentioned, for example.

  The olefin resin film can be provided with the function of a retardation film by stretching and imparting refractive index anisotropy to the film. The stretching method may be appropriately selected depending on the required refractive index anisotropy, and is not particularly limited, and examples thereof include longitudinal uniaxial stretching, transverse uniaxial stretching, and longitudinal biaxial stretching.

  Since an olefin resin has positive refractive index anisotropy and the refractive index becomes largest in the direction in which stress is applied, a uniaxially stretched film usually has a refractive index anisotropy of nx> ny ≒ nz. Give sex. Here, nx is the refractive index in the in-plane slow axis direction of the film (the direction in which the refractive index is maximum in the plane, and the stretching direction in the case of a resin having positive refractive index anisotropy), and ny is the film The refractive index is in the in-plane fast axis direction (direction orthogonal to the fast axis in the plane), and nz is the refractive index in the normal direction of the film. The film in which the olefin resin is sequentially biaxially stretched usually gives a refractive index anisotropy of nx> ny> nz.

  In addition, in order to impart desired refractive index properties, a retardation film is produced by a method of laminating a heat-shrinkable film to a target film and replacing the stretching process or shrinking the film along with the stretching process. You can also. This operation is usually performed to obtain a retardation film in which the refractive index anisotropy is nx> ny> nz or nz> nx ≧ ny.

  A commercially available product may be used as the retardation film made of an olefin-based resin. For example, in the case of a retardation film made of a cyclic olefin-based resin, "Zeonor film" manufactured by Nippon Zeon Co., Ltd., manufactured by JSR Corporation And “Essina retardation film” manufactured by Sekisui Chemical Co., Ltd., and the like.

  It is preferable to use an adhesive for bonding of the polarizer protective film and the polarizer, and bonding of the polarizer and the transparent resin film. By using an adhesive, the polarizer protective film and the polarizer, and the polarizer and the transparent resin film are bonded via the adhesive layer. Moreover, it is preferable to perform corona discharge treatment, plasma irradiation treatment, electron beam irradiation treatment, and other surface activation treatment on at least one of the bonding surfaces prior to bonding.

  The adhesive for forming the adhesive layer can be arbitrarily selected and used from those which develop adhesion to the respective members. Typically, a water-based adhesive, ie, an active energy ray-curable adhesive containing an adhesive component dissolved in water or an adhesive component dispersed in water, or a component that cures upon irradiation with an active energy ray It can be mentioned. Among them, active energy ray-curable adhesives are preferable from the viewpoint of productivity.

  As a water-based adhesive, the composition which used polyvinyl alcohol-type resin and urethane resin as a main component is mentioned as a preferable adhesive, for example.

  When a polyvinyl alcohol-based resin is used as the main component of the water-based adhesive, examples of polyvinyl alcohol-based resins include partially saponified polyvinyl alcohol and completely saponified polyvinyl alcohol, as well as carboxyl group-modified polyvinyl alcohol and acetoacetyl group-modified polyvinyl alcohol And modified polyvinyl alcohol resins such as methylol group-modified polyvinyl alcohol and amino group-modified polyvinyl alcohol. When using polyvinyl alcohol-type resin as an adhesive agent component, the adhesive agent is prepared as aqueous solution of polyvinyl alcohol-type resin in many cases. The concentration of the polyvinyl alcohol resin in the aqueous adhesive solution is preferably 1 to 10 parts by weight, and more preferably 1 to 5 parts by weight with respect to 100 parts by weight of water.

  In order to improve adhesiveness, it is preferable to add a curable component such as glyoxal or a water-soluble epoxy resin or a crosslinking agent to a water-based adhesive containing a polyvinyl alcohol-based resin as a main component. As a water-soluble epoxy resin, for example, a polyamide polyamine obtained by reacting epichlorohydrin with a polyamide polyamine obtained by the reaction of a polyalkylene polyamine such as diethylenetriamine or triethylenetetramine and a dicarboxylic acid such as adipic acid An epoxy resin etc. are mentioned. As a polyamide polyamine epoxy resin, a commercial item may be used, for example, Sumires resin 650 and Sumires resin 675 by Sumika Chemtex Co., Ltd., and WS-525 made by Japan PMC Ltd. Etc. The amount of the curable component or the crosslinking agent added is preferably 1 to 100 parts by weight, and more preferably 1 to 50 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin. When the addition amount is small, the adhesion improvement effect is reduced, while when the addition amount is large, the adhesive layer may become brittle.

  When a urethane resin is used as the main component of the water-based adhesive, examples of a suitable adhesive composition include a mixture of a polyester ionomer type urethane resin and a compound having a glycidyloxy group. The polyester-based ionomer-type urethane resin referred to here is a urethane resin having a polyester skeleton, into which a small amount of ionic component (hydrophilic component) is introduced. Ionomer-type urethane resins are preferable as water-based adhesives because they are emulsified in water directly without using an emulsifier to form an emulsion.

  When using an activated energy ray-curable adhesive, an epoxy compound, an oxetacene compound, and an acrylic compound may be used as a component that is cured by irradiation of an active energy ray that constitutes the same (hereinafter sometimes simply referred to as "curable component"). A compound etc. are mentioned. In the case of using a cationically polymerizable compound such as an epoxy compound or an oxacene compound, a cationic polymerization initiator is blended. When a radical polymerizable compound such as an acrylic compound is used, a radical polymerization initiator is blended. Among them, an adhesive containing an epoxy compound as one of the curable components is preferable, and an adhesive containing an alicyclic epoxy compound having an epoxy group directly bonded to a saturated carbon ring as one of the curable components is more preferable. In addition, an oxetane compound may be used in combination therewith.

  As the epoxy compound, a commercially available product may be used. For example, "Epicoat" series manufactured by Japan Epoxy Resins Co., Ltd., "Epiclon" series manufactured by DIC Corporation, "Epototh" series manufactured by Toto Kasei Co., Ltd., ADEKA “Adeka Resin” series, Nagase ChemteX Co., Ltd. “Denacol” series, Dow Chemical Co. “Dow Epoxy” series, Nissan Chemical Industries Co., Ltd. “Tepic”.

  As a cycloaliphatic epoxy compound in which an epoxy group is directly bonded to a saturated carbon ring, a commercially available product may be used. For example, “Celoxide” series and “Cyclomer” series manufactured by Daicel Chemical Industries, Ltd., Dow Examples include “Cyracure” Leeds manufactured by Chemical Company.

  As the oxetane compound, a commercially available product may be used, and examples thereof include “Aron oxetane” series manufactured by Toagosei Co., Ltd., and “ETERANACOLL” series manufactured by Ube Industries, Ltd.

  As a cationic polymerization initiator, a commercial item may be used, for example, "Kayarad" series manufactured by Nippon Kayaku Co., Ltd., "Syuracure" series manufactured by Union Carbide, a photoacid generator manufactured by San-Apro Co., Ltd. Certain "CPI" series, "TAZ", "BBI" and "DTS" which are photo acid generators manufactured by Midori Chemical Co., Ltd., "Adeca Optomer" series manufactured by ADEKA Co., Ltd., and "RHODORSIL" series manufactured by Rhodia Etc.

  The active energy ray curable adhesive can contain a photosensitizer, if necessary. By using a photosensitizer, the reactivity can be improved, and the mechanical strength and the adhesive strength of the cured product layer can be further improved. Examples of the photosensitizer include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, anthracene compounds, halogen compounds, photoreducible dyes and the like.

  Various additives can be added to the active energy ray-curable adhesive as long as the adhesion is not impaired. As an additive, an ion trap agent, antioxidant, a chain transfer agent, a tackifier, a thermoplastic resin, a filler, a flow control agent, a plasticizer, an antifoamer etc. are mentioned, for example. Furthermore, in the range which does not impair the adhesiveness, it is also possible to blend a curable component that cures by a reaction mechanism different from cationic polymerization.

  The active energy ray-curable adhesive described above may have the same composition or different compositions, but it is preferable to simultaneously perform irradiation of active energy rays for curing the two.

  As an active energy ray, an X ray, an ultraviolet-ray, a visible ray etc. are mentioned, for example. Among them, ultraviolet light is preferred from the viewpoints of ease of use and easiness of preparation of an active energy ray-curable adhesive, stability and curing performance. Examples of the light source of ultraviolet light include low pressure mercury lamps, medium pressure mercury lamps, high pressure mercury lamps, ultra high pressure mercury lamps, chemical lamps, black light lamps, microwave excited mercury lamps, metal halide lamps and the like.

  The thickness of the adhesive layer obtained using the active energy ray-curable adhesive is preferably 1 to 50 μm, and more preferably 1 to 10 μm.

  The polarizing plate can be bonded to a liquid crystal cell to form a liquid crystal panel used in a liquid crystal display device. It is preferable that the polarizing plate and the liquid crystal cell be bonded using a pressure sensitive adhesive via a pressure sensitive adhesive layer. The pressure-sensitive adhesive layer is generally formed of an acrylic pressure-sensitive adhesive containing an acrylic ester as a main component and an acrylic resin obtained by copolymerizing a functional group-containing acrylic monomer as a pressure-sensitive adhesive component. The liquid crystal panel formed by bonding a polarizing plate to a liquid crystal cell via an adhesive layer can be used for a liquid crystal display device.

  EXAMPLES Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

The ultraviolet absorbers used in the following examples and comparative examples are as follows.
UV absorber A1: UV absorber “Kemisorb 102” manufactured by Chemi-Pro Chemical Co., Ltd. (absorption maximum: wavelength 280 nm, molar absorption coefficient: 68.3 L / mol · cm, weight average molecular weight: 508.9, triazine-based UV absorber)
UV absorber A2: BASF Corporation UV absorber “Tinuvin 1577” (absorption maximum: wavelength 280 nm, molar extinction coefficient: 82.0 L / mol · cm, weight average molecular weight 425, triazine-based UV absorber)
UV absorber B1: UV absorber "LAF 70" manufactured by ADEKA Corporation (absorption maximum: wavelength 356 nm, molar absorption coefficient: 65.7 L / mol · cm, weight average molecular weight: 699.9, triazine-based UV absorber)
UV absorber B2: UV absorber "ADEKA STAB LA 31" manufactured by ADEKA Corporation (absorption maximum: wavelength 350 nm, molar absorptivity: 18.0 L / mol · cm, weight average molecular weight: 658, benzotriazole based UV absorber)

Example 1
First, 100 parts by weight of acrylic resin "Sumipex MH" (manufactured by Sumitomo Chemical Co., Ltd.), 1.2 parts by weight of ultraviolet absorber A1, 0.6 parts by weight of ultraviolet absorber B1, and 0.9 parts by weight of The ultraviolet absorber B2 was mixed to obtain a resin composition, and the obtained resin composition was melt-kneaded with a single screw extruder with a screw diameter of 65 mm and a molten resin was supplied to a T-die. Then, the supplied molten resin is continuously extruded from the T-die into a film, and the film-like molten resin continuously extruded from the T-die is further interposed between a pair of smooth metal rolls. The film was sandwiched, molded and cooled to obtain a 40 μm-thick polarizer protective film.

(Example 2)
A 40 μm-thick polarizer protective film was obtained in the same manner as in Example 1 except that the ultraviolet absorber A1 was changed to 0.9 parts by weight.
(Comparative example 1)
A polarizer protective film having a thickness of 40 μm in the same manner as in Example 1 except that the ultraviolet absorber A1 was 0.5 parts by weight, the ultraviolet absorber B1 was 0.9 parts by weight, and the ultraviolet absorber B2 was not mixed. I got
(Comparative example 2)
A polarizer protective film having a thickness of 40 μm was obtained in the same manner as in Comparative Example 1 except that the ultraviolet absorber A1 was replaced by 0.5 parts by weight of the ultraviolet absorber A2.

The light transmittance and the value of b ^* were evaluated for each of the obtained polarizer protective films (Examples 1 and 2 and Comparative Examples 1 and 2) by the following methods.

<Light transmittance evaluation>
About each obtained polarizer protective film, the light transmittance in wavelength 260 nm and the light transmittance in wavelength 380 nm were measured using the spectrophotometer U-4100 by Hitachi High-Tech Fielding Co., Ltd. product. The measured results are shown in Table 1.
<b ^* Evaluation>
About each obtained polarizer protective film, b ^* was measured by the program mounted using the spectrophotometer U-4100 by Hitachi High-Tech Fielding Co., Ltd. product. The measured results are shown in Table 1.

  About each obtained polarizer protective film (Example 1, 2 and Comparative Examples 1, 2), the polarizing plate was produced by the following method, respectively, and the yellowishness of the polarizing plate was evaluated by the following method.

  The polarizer protective films obtained in Examples 1 and 2 and Comparative Examples 1 and 2 are mainly epoxy compounds on one side of a polarizer having a thickness of about 30 μm in which iodine is adsorbed and oriented to polyvinyl alcohol. Another retardation film, which is formed by laminating a cycloolefin resin film biaxially stretched on another surface of a polarizer, is bonded to the other surface of the polarizer through another ultraviolet curable adhesive as a component It was bonded via an ultraviolet curable adhesive and then irradiated with ultraviolet light to cure the ultraviolet curable adhesive, to obtain a polarizing plate.

<Yellowing evaluation>
The obtained polarizing plates (Examples 1 and 2 and Comparative Examples 1 and 2) were visually observed, and those which looked yellow were evaluated as x, and those which did not look yellow were evaluated as ○. The evaluated results are shown in Table 1.

Claims (11)

A polarizer protective film comprising an ultraviolet absorber A having an absorption maximum at a wavelength of 200 to 300 nm, an ultraviolet absorber B having an absorption maximum at a wavelength of 320 to 400 nm, and a thermoplastic resin, and the total of the ultraviolet absorbers A and B The amount is 3 parts by weight or less with respect to 100 parts by weight of the thermoplastic resin , the light transmittance at a wavelength of 260 nm is 3% or less, the light transmittance at a wavelength of 380 nm is 5% or less, The value of b, ^* is 0.50 or less, Polarizer protective film characterized by the above-mentioned. It is a polarizer protective film containing the ultraviolet absorber A which has an absorption maximum in wavelength 200-300 nm, the ultraviolet absorber B which has an absorption maximum in wavelength 320-400 nm, and a thermoplastic resin, and said ultraviolet absorber B is 2 or more types. The light transmittance at a wavelength of 260 nm is 3% or less, the light transmittance at a wavelength of 380 nm is 5% or less, and b ^* The value of is 0.50 or less, The polarizer protective film characterized by the above-mentioned. The polarizer protective film according to claim 2 , wherein a total amount of the ultraviolet absorbers A and B is 5 parts by weight or less with respect to 100 parts by weight of the thermoplastic resin. The polarizer protective film according to any one of claims 1 to 3 , wherein the weight average molecular weight of each of the ultraviolet absorbers A and B is 500 to 1,000. The ultraviolet absorber A is one or more selected from the group consisting of triazine based ultraviolet absorbers, benzotriazole based ultraviolet absorbers, benzoate based ultraviolet absorbers, benzophenone based ultraviolet absorbers and cyanoacrylate based ultraviolet absorbers. The polarizer protective film in any one of 1-4 . The UV absorber B is one or more selected from the group consisting of triazine UV absorbers, benzotriazole UV absorbers, benzoate UV absorbers, benzophenone UV absorbers and cyanoacrylate UV absorbers. The polarizer protective film in any one of 1-5 . Thermoplastic resins include acrylic resins, polycarbonate resins, polyester resins, norbornene resins, cellulose ester resins, cyclic olefin resins, styrene resins, methyl methacrylate-styrene resins, acrylonitrile-styrene resins and acrylonitrile The polarizer protective film according to any one of claims 1 to 6 , which is at least one selected from the group consisting of -butadiene-styrene resin. Polarizer protective film according to any one of claims 1 to 7, are arranged in a at least one surface of a polarizer polarizing plate. The polarizing plate according to claim 8 , wherein the polarizer protective film and the polarizer are bonded via an adhesive layer. 10. The polarizing plate according to claim 9 , wherein the adhesive layer is formed of an active energy ray curable adhesive. The polarizing plate according to any one of claims 8 to 10 , wherein the polarizer is formed by adsorption and orientation of a dichroic dye on a polyvinyl alcohol resin film.