JP2018158987A - Easily-adhesive composition, and polarizer protective film, polarization film and image display device containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an easily-adhesive composition that serves as raw material for an easily-adhesive layer formed between two or more films when laminating the films, and achieves improved adhesiveness even when the layer thickness is reduced.SOLUTION: An easily-adhesive composition contains: (A) component comprising at least one selected from the group consisting of an acid anhydride group-containing silane coupling agent, an acetoacetyl group-containing silane coupling agent, an isocyanuric group-containing silane coupling agent and a carboxyl group-containing polymer, and (B) component comprising a urethane resin.SELECTED DRAWING: None

Description

  The present invention relates to an easy-adhesive composition, a polarizer protective film including the same, a polarizing film, and an image display device. In more detail, this invention relates to the polarizer protective film which can make adhesiveness with a polarizer, and the optical reliability of a polarizing film compatible.

  With respect to a laminated film in which two or more films are laminated, an easy-adhesion layer may be formed on the laminated surface of at least one film for the purpose of enhancing the adhesion between the films. Such an easy-adhesion layer is effective in improving the adhesion, but if the thickness is increased, the characteristics of the laminated film may be impaired, and it is necessary to examine the balance between the thickness and the improvement in adhesion.

  By the way, in a liquid crystal display device which is a typical image display device, it is indispensable to dispose polarizing films on both sides of the liquid crystal cell due to the image forming method. The polarizing film is usually formed by adhering a polarizer protective film on both sides of a polarizer using an adhesive. An acrylic resin film has been proposed as a material for forming a polarizer protective film. Moreover, in order to improve the adhesiveness of a polarizer and an acrylic resin film, providing an easily bonding layer between a polarizer and an acrylic resin film is proposed (for example, patent document 1). However, if the easy-adhesion layer is thick, there is a problem that the optical reliability of the polarizing film is impaired. On the other hand, if the easy-adhesion layer is thin, the optical reliability of the polarizing film can be ensured, but there is a problem that the adhesiveness with the polarizer is poor.

JP 2007-127893 A

  The present invention has been made in order to solve the above-described conventional problems. When two or more films are laminated, it becomes a raw material for an easy-adhesion layer formed between the films. It aims at providing the easily adhesive composition which can improve property. Another object of the present invention is to provide a polarizer protective film that, when used for a polarizing film, can improve the adhesiveness with the polarizer without impairing the optical reliability of the polarizing film. Furthermore, an object of this invention is to provide the polarizing film excellent in the adhesiveness of a polarizer and a polarizer protective film, and optical reliability.

  The above problem can be solved by the following configuration. That is, this invention consists of at least 1 sort (s) selected from the group which consists of an acid anhydride group containing silane coupling agent, an acetoacetyl group containing silane coupling agent, an isocyanuric group containing silane coupling agent, and a carboxyl group containing polymer ( The present invention relates to an easy-adhesive composition comprising an A) component and a (B) component made of a urethane resin.

  The easy-adhesive composition preferably further contains fine particles.

  In the easy-adhesive composition, the urethane resin preferably has a carboxyl group.

  In the easy-adhesive composition, the fine particles are preferably colloidal silica.

  The present invention also relates to a polarizer protective film comprising an easy-adhesion layer formed of any one of the above-described easy-adhesive compositions on at least one surface of a resin film.

  In the polarizer protective film, the resin film is preferably a (meth) acrylic resin film.

  In the polarizer protective film, the (meth) acrylic resin film preferably has a lactone ring structure.

  In the polarizer protective film, it is preferable that a corona discharge treatment or a plasma treatment is performed on the side of the resin film on which the easy adhesion layer is formed.

  Moreover, this invention relates to the polarizing film by which the polarizer protective film in any one of the said was laminated | stacked on the polarizer from the side in which the said easily bonding layer was formed through the adhesive bond layer. As the polarizing film, the adhesive layer is preferably formed of a polyvinyl alcohol-based adhesive.

  Furthermore, this invention relates to an image display apparatus provided with the said polarizing film.

  The easy-adhesive composition according to the present invention is at least selected from the group consisting of an acid anhydride group-containing silane coupling agent, an acetoacetyl group-containing silane coupling agent, an isocyanuric group-containing silane coupling agent, and a carboxyl group-containing polymer. (A) component which consists of 1 type, and (B) component which consists of urethane resins are contained. Since the easy-adhesion layer formed with such an easy-adhesive composition is excellent in adhesiveness, the adhesiveness between films can be improved even if the layer thickness is reduced. In particular, the easy-adhesion layer formed from the easy-adhesive composition according to the present invention has improved adhesion with a resin film, such as a (meth) acrylic resin film, and is excellent in adhesiveness.

  A polarizer protective film comprising an easy-adhesion layer formed from such an easy-adhesive composition is excellent in adhesiveness with the polarizer. As a result, when a polarizing film is constituted, the adhesiveness with the polarizer and the optical reliability of the polarizing film can be improved in a balanced manner.

  Moreover, since a polarizing film provided with the easily bonding layer formed with the easily bonding agent composition which concerns on this invention between a polarizer and a polarizer protective film, since this easily bonding layer has high adhesive force, it is easy to adhere. The adhesiveness between the polarizer and the polarizer protective film can be improved while reducing the thickness of the layer. As a result, the polarizing film according to the present invention can improve the adhesion between the polarizer and the polarizer protective film and the optical reliability in a balanced manner.

  In particular, when a polarizer protective film including an easy-adhesion layer formed from the easy-adhesive composition according to the present invention and a polarizer are laminated via an adhesive layer formed of a polyvinyl alcohol-based adhesive, Functional group of component (A) in the adhesive layer, specifically silanol produced by hydrolysis of alkoxysilane in silane coupling agent, carboxyl group remaining in carboxyl group-containing polymer, and polyvinyl alcohol A strong interaction is produced with the adhesive. Moreover, the functional group which (A) component in an easily bonding layer has is a silica particle surface, when the hydroxyl group and carboxyl group in (B) component, and also when an easily adhesive composition contains colloidal silica as microparticles | fine-particles. A strong interaction with Thereby, strong interface adhesive force arises between the easily bonding layer formed on the polarizer protective film, and the adhesive bond layer formed with the polyvinyl alcohol-type adhesive agent. This makes it possible to further reduce the thickness of the easy-adhesion layer while increasing the adhesive force, and thus the adhesiveness between the polarizer and the polarizer protective film and the optical reliability can be improved with a particularly good balance.

  Hereinafter, although preferable embodiment of this invention is described, this invention is not limited to these embodiment.

  The easy-adhesive composition according to the present invention can be suitably used as a raw material for forming an easy-adhesion layer on at least one surface of a resin film. The polarizer protective film according to the present invention includes an easy-adhesion layer on at least one surface of the resin film. Especially as a resin film, a (meth) acrylic-type resin film can be used conveniently.

(Polarizer protective film)
A. Easy adhesion layer The easy adhesion layer is at least one selected from the group consisting of an acid anhydride group-containing silane coupling agent, an acetoacetyl group-containing silane coupling agent, an isocyanuric group-containing silane coupling agent, and a carboxyl group-containing polymer. (A) component which consists of, and (B) component which consists of urethane resin, and is formed with the easily-adhesive composition. Thereby, even if the thickness of an easily bonding layer is thin, the adhesive force between a polarizer protective film and a polarizer can be improved. The easy-adhesive composition is preferably aqueous. The aqueous system is superior to the solvent system in terms of environment and can be excellent in workability.

(I) Acid anhydride group-containing silane coupling agent Examples of the acid anhydride group in the acid anhydride group-containing silane coupling agent include succinic anhydride and, for example, ethylenically unsaturated dicarboxylic acid (for example, maleic acid, Itaconic acid, citraconic acid, phthalic acid, etc.) or monocarboxylic acid anhydride type. The linking group that can be interposed between the acid anhydride and the alkoxysilane group is not particularly limited, and examples thereof include an alkyl group having 1 to 14 carbon atoms and an alkylene glycol skeleton such as ethylene glycol and propylene glycol. Examples of the alkoxysilane group include alkoxy groups such as methoxy, ethoxy, and propoxy. Specific examples of the compound include 3-trimethoxysilylpropyl succinic anhydride.

(Ii) Acetoacetyl group-containing silane coupling agent The linking group that can be interposed between the acetoacetyl group and the alkoxysilane group in the acetoacetyl group-containing silane coupling agent is not particularly limited. And an alkylene glycol skeleton such as ethylene glycol and propylene glycol. Examples of the alkoxysilane group include alkoxy groups such as methoxy, ethoxy, and propoxy. Specific examples of the compound include “A-100” manufactured by Soken Chemical Co., Ltd.

(Iii) Isocyanuric Group-Containing Silane Coupling Agent The linking group that can be interposed between the isocyanuric group and the alkoxysilane group in the isocyanuric group-containing silane coupling agent is not particularly limited, but for example, an alkyl group having 1 to 14 carbon atoms And alkylene glycol skeletons such as ethylene glycol and propylene glycol. Examples of the alkoxysilane group include alkoxy groups such as methoxy, ethoxy, and propoxy. Specific examples of the compound include “KBM-9659” and “KBE-9659” manufactured by Shin-Etsu Chemical Co., Ltd.

(Iv) Carboxyl group-containing polymer As the carboxyl group-containing polymer, a polymer having a molecular weight of 1500 or more is preferable in order to ensure adhesive strength. For example, A-30 (polyammonium acrylate aqueous solution), A-7075 and B-300K (carboxylic acid copolymer emulsion), AC-10L (polyacrylic acid aqueous solution), ARUFON UC- manufactured by Toa Gosei Co., Ltd. Examples thereof include carboxyl group-containing polymers such as 3000, ARUFUON UC-3080, ARUFON UC-3900, ARUFON UC-3910, ARUFON UC-3920, ARUFON UC-3510, and the like.

  In the present invention, the proportion of the component (A) in the entire easy-adhesion layer after drying (solid content) is 0.5 to 50 parts by weight when the total solid content of the easy-adhesion layer after drying is 100 parts by weight. The range is preferably 0.7 to 45 parts by weight, more preferably 1 to 40 parts by weight. In the case of a blending amount exceeding 50 parts by weight, the ratio of the component for adhering to the polarizer or the protective film is relatively insufficient, and the adhesiveness may be lowered. Further, when the amount is less than 0.5 parts by weight, the effect of adhesion and water resistance is not sufficiently exhibited.

  The easy-adhesive composition according to the present invention further contains a component (B) made of a urethane resin. Thereby, when an easily bonding layer is formed on a resin film, adhesiveness with a resin film can be improved.

  The urethane resin is typically obtained by reacting a polyol and a polyisocyanate. The polyol is not particularly limited as long as it has two or more hydroxyl groups in the molecule, and any suitable polyol can be adopted. For example, polyacryl polyol, polyester polyol, polyether polyol and the like can be mentioned. These may be used alone or in combination of two or more.

  The polyacryl polyol is typically obtained by copolymerizing a (meth) acrylic acid ester and a monomer having a hydroxyl group. Examples of the (meth) acrylic acid ester include methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, and the like. Examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxy (meth) acrylate. Hydroxyalkyl esters of (meth) acrylic acid such as butyl, 4-hydroxybutyl (meth) acrylate, 2-hydroxypentyl (meth) acrylate; mono (meth) acrylic acid of polyhydric alcohols such as glycerin and trimethylolpropane Examples of the ester include N-methylol (meth) acrylamide. These may be used alone or in combination of two or more.

  The polyacryl polyol may be copolymerized with other monomers in addition to the monomer components. As the other monomer, any appropriate monomer can be adopted as long as copolymerization is possible. Specifically, unsaturated monocarboxylic acids such as (meth) acrylic acid; unsaturated dicarboxylic acids such as maleic acid and anhydrides and mono- or diesters thereof; unsaturated nitriles such as (meth) acrylonitrile; (meth) Unsaturated amides such as acrylamide and N-methylol (meth) acrylamide; Vinyl esters such as vinyl acetate and vinyl propionate; Vinyl ethers such as methyl vinyl ether; α-olefins such as ethylene and propylene; Vinyl chloride and vinylidene chloride Halogenated α, β-unsaturated aliphatic monomers such as α; β-unsaturated aromatic monomers such as styrene and α-methylstyrene. These may be used alone or in combination of two or more.

  The polyester polyol is typically obtained by reacting a polybasic acid component with a polyol component. Examples of the polybasic acid component include orthophthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, tetrahydrophthalic acid and the like. Aromatic dicarboxylic acids: oxalic acid, succinic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, octadecanedicarboxylic acid, tartaric acid, alkylsuccinic acid Aliphatic dicarboxylic acids such as linolenic acid, maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid; hexahydrophthalic acid, tetrahydrophthalic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, etc. The alicyclic dicar Phosphate; or acid anhydrides thereof, alkyl esters, reactive derivatives such as acid halides and the like. These may be used alone or in combination of two or more.

  Examples of the polyol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, and 1,6-hexanediol. 1,8-octanediol, 1,10-decanediol, 1-methyl-1,3-butylene glycol, 2-methyl-1,3-butylene glycol, 1-methyl-1,4-pentylene glycol, 2 -Methyl-1,4-pentylene glycol, 1,2-dimethyl-neopentyl glycol, 2,3-dimethyl-neopentyl glycol, 1-methyl-1,5-pentylene glycol, 2-methyl-1,5 -Pentylene glycol, 3-methyl-1,5-pentylene glycol, 1,2-dimethylbutylene Recall, 1,3-dimethylbutylene glycol, 2,3-dimethylbutylene glycol, 1,4-dimethylbutylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, 1,4-cyclohexanedimethanol, Examples include 1,4-cyclohexanediol, bisphenol A, bisphenol F, hydrogenated bisphenol A, hydrogenated bisphenol F, and the like. These may be used alone or in combination of two or more.

  The polyether polyol is typically obtained by adding an alkylene oxide to a polyhydric alcohol by ring-opening polymerization. Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, trimethylolpropane, and the like. Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, and tetrahydrofuran. These may be used alone or in combination of two or more.

  Examples of the polyisocyanate include tetramethylene diisocyanate, dodecamethylene diisocyanate, 1,4-butane diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and lysine. Aliphatic diisocyanates such as diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate; isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4'-cyclohexylmethane diisocyanate, 1,4 -Cycloaliphatic diisocyanate, methylcyclohexylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane and other alicyclic groups Isocyanate; tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, 1 , 5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate and other aromatic diisocyanates; dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, α, α, α, α-tetramethylxylylene Examples include aromatic aliphatic diisocyanates such as range isocyanate. These may be used alone or in combination of two or more.

  The urethane resin preferably has a carboxyl group. By having a carboxyl group, a polarizer protective film excellent in adhesiveness with a polarizer (particularly under high temperature and high humidity) can be provided. The urethane resin having a carboxyl group can be obtained, for example, by reacting a chain extender having a free carboxyl group in addition to the polyol and the polyisocyanate. Examples of the chain extender having a free carboxyl group include dihydroxycarboxylic acid and dihydroxysuccinic acid. Examples of the dihydroxycarboxylic acid include dialkylolalkanoic acids such as dimethylolalkanoic acid (for example, dimethylolacetic acid, dimethylolbutanoic acid, dimethylolpropionic acid, dimethylolbutyric acid, dimethylolpentanoic acid). These may be used alone or in combination of two or more.

  In the production of the urethane resin, in addition to the above components, other polyols and other chain extenders can be reacted. Examples of other polyols include sorbitol, 1,2,3,6-hexanetetraol, 1,4-sorbitan, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, and trimethylol. Examples thereof include polyols having 3 or more hydroxyl groups such as ethane, trimethylolpropane and pentaerythritol. Examples of other chain extenders include ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 1,6 -Glycols such as hexanediol and propylene glycol; aliphatic diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, 1,4-butanediamine, and aminoethylethanolamine; isophoronediamine, 4,4'-dicyclohexylmethanediamine, etc. Alicyclic diamines; and aromatic diamines such as xylylenediamine and tolylenediamine.

  Arbitrary appropriate methods can be employ | adopted for the manufacturing method of the said urethane resin. Specific examples include a one-shot method in which the above components are reacted at once and a multi-stage method in which the components are reacted in stages. When the urethane resin has a carboxyl group, it is preferably a multistage method. This is because a carboxyl group can be easily introduced. In the production of the urethane resin, any suitable urethane reaction catalyst can be used.

  When the easy-adhesive composition is water-based, a neutralizer is preferably used in the production of the urethane resin. By using a neutralizing agent, the stability of the urethane resin in water can be improved. Examples of the neutralizing agent include ammonia, N-methylmorpholine, triethylamine, dimethylethanolamine, methyldiethanolamine, triethanolamine, morpholine, tripropylamine, ethanolamine, triisopropanolamine, 2-amino-2-methyl-1 -Propanol etc. are mentioned. These may be used alone or in combination of two or more.

  When the easy-adhesive composition is water-based, an organic solvent that is inert to the polyisocyanate and is compatible with water is preferably used in the production of the urethane resin. Examples of the organic solvent include ester solvents such as ethyl acetate, butyl acetate, and ethyl cellosolve acetate; ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ether solvents such as dioxane, tetrahydrofuran, and propylene glycol monomethyl ether. A solvent etc. are mentioned. These may be used alone or in combination of two or more.

  The number average molecular weight of the urethane resin is preferably 5,000 to 600,000, and more preferably 10,000 to 400,000. The acid value of the urethane resin is preferably 10 or more, more preferably 10 to 50, and particularly preferably 20 to 45. When the acid value is within such a range, the adhesion with the polarizer can be more excellent.

  The easy-adhesive composition preferably contains a cross-linking agent. Arbitrary appropriate crosslinking agents can be employ | adopted for the said crosslinking agent. Specifically, when the urethane resin has a carboxyl group, the crosslinking agent preferably includes a polymer having a group capable of reacting with the carboxyl group. Examples of the group that can react with a carboxyl group include an organic amino group, an oxazoline group, an epoxy group, and a carbodiimide group. Preferably, the crosslinking agent has an oxazoline group. Among these, the crosslinking agent having an oxazoline group has a long pot life at the time of mixing with the urethane resin, and has a good workability because the crosslinking reaction proceeds by heating.

  Any appropriate polymer can be adopted as the polymer. Examples thereof include acrylic polymers and styrene / acrylic polymers. An acrylic polymer is preferable. By using an acrylic polymer, the adhesion to the polarizer can be further improved. Moreover, it can be stably compatible with an aqueous easy-to-adhesive composition and can be well crosslinked with the urethane resin.

  The content of the crosslinking agent (solid content) in the easy-adhesive composition is preferably 1 to 30 parts by weight, more preferably 3 parts per 100 parts by weight of the urethane resin (solid content) as the component (B). ~ 20 parts by weight. By setting it as 1 weight part or more, it can be excellent in adhesiveness with a polarizer. On the other hand, by setting it as 30 weight part or less, it can suppress that a phase difference expresses in an easily bonding layer.

  In the present invention, the proportion of the component (B) in the entire easy-adhesion layer after drying (solid content) is 30 to 99.2 parts by weight when the total solid content of the easy-adhesion layer after drying is 100 parts by weight. The range is preferably 40 to 98.8 parts by weight, more preferably 50 to 98.4 parts by weight. In the case of a compounding amount exceeding 99.2 parts by weight, the ratio of components for adhering to the adhesive layer and the protective film is relatively insufficient, and the adhesiveness may be lowered. Moreover, when it is less than 30 weight part, there exists a possibility that the storage stability of an easily adhesive composition may deteriorate or adhesiveness may fall.

  As described above, the easy-adhesive composition is preferably aqueous. The concentration of the urethane resin in the easy-adhesive composition is preferably 1.5 to 15% by weight, more preferably 2 to 10% by weight. This is because the workability at the time of forming the easy adhesion layer can be excellent.

  The easy-adhesive composition according to the present invention may contain fine particles in addition to the component (A) and the component (B). The polarizer protective film formed of the easy-adhesive composition containing fine particles on at least one surface of the resin film is excellent in winding properties because blocking that occurs during winding is effectively suppressed. Specifically, by forming an easy-adhesion layer with an easy-adhesive composition containing the component (A) and the component (B) and fine particles, a minute unevenness is formed on the surface of the easy-adhesion layer, In particular, the frictional force at the contact surface between the (meth) acrylic resin film and the easy adhesion layer and / or the easy adhesion layer can be reduced. As a result, in the process of winding the polarizer protective film into a roll, it is possible to effectively prevent the occurrence of defects such as wrinkles and wrinkle marks without using interleaving paper, and a polarizer excellent in winding properties. A protective film may be provided.

  Any appropriate fine particles can be used as the fine particles. Water-dispersible fine particles are preferable. Specifically, both inorganic fine particles and organic fine particles can be used. Examples of the inorganic fine particles include inorganic oxides such as silica, titania, alumina, zirconia, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate, and the like. Can be mentioned. Examples of the organic fine particles include silicone resins, fluorine resins, (meth) acrylic resins, and the like. Among these, silica is preferable. This is because the blocking ability can be further improved, the transparency is excellent, no haze is generated, and there is no coloring, so the influence on the optical properties of the polarizing film is smaller. Further, since silica has good dispersibility and dispersion stability in the easy-adhesive composition, it can be more excellent in workability when forming the easy-adhesive layer. Further, silica is excellent in adhesion to a (meth) acrylic resin film.

  The particle diameter (average primary particle diameter) of the fine particles is preferably 10 to 200 nm, more preferably 20 to 60 nm. By using fine particles of such a particle size, unevenness is appropriately formed on the surface of the easy-adhesion layer, and the resin film, in particular, the (meth) acrylic resin film and the easy-adhesion layer and / or the easy-adhesion layer contact each other. The frictional force on the surface can be effectively reduced. As a result, the blocking inhibition ability can be further improved. Moreover, since the light scattering by particle | grains can be suppressed, so that an average primary particle diameter is smaller than visible wavelength, and the smaller, the influence which it has on the optical characteristic of a polarizing film can be suppressed more.

  When the easy-adhesive composition is aqueous, the fine particles are preferably formulated as an aqueous dispersion. Specifically, when silica is employed as the fine particles, it is preferably blended as colloidal silica. Commercially available products can be used as they are as colloidal silica. Commercially available products include, for example, the Quartron PL series manufactured by Fuso Chemical Industry Co., Ltd., the Snowtex series manufactured by Nissan Chemical Industries, Ltd., the Aerodisp series and AEROSIL series manufactured by Nippon Aerosil Co., Ltd.

  The easy-adhesive composition may further include any appropriate additive. Examples of additives include anti-blocking agents, dispersion stabilizers, thixotropic agents, antioxidants, ultraviolet absorbers, antifoaming agents, thickeners, dispersants, surfactants, catalysts, fillers, lubricants, and antistatic agents. Agents and the like.

  In the present invention, the proportion of the fine particles in the entire easy-adhesion layer after drying (solid content) is preferably 0.3 to 20 parts by weight, when the total solid content of the easy-adhesion layer after drying is 100 parts by weight. Is 0.5 to 15 parts by weight, more preferably 0.6 to 10 parts by weight. By setting it in such a range, unevenness is appropriately formed on the surface of the easy-adhesion layer, and the frictional force at the contact surface between the (meth) acrylic resin film and the easy-adhesion layer and / or the easy-adhesion layer is effective. Can be reduced. As a result, the blocking inhibition ability can be further improved. Moreover, the influence which acts on the optical characteristic of a polarizing film can be suppressed more.

  The thickness of the easy-adhesion layer can be set to any appropriate value. Preferably it is 0.1-10 micrometers, More preferably, it is 0.1-5 micrometers, Most preferably, it is 0.2-1.5 micrometers. By setting to such a range, it can be excellent in adhesiveness with a polarizer, and it can suppress that a phase difference expresses in an easily bonding layer.

  The coefficient of friction between the resin film, particularly the (meth) acrylic resin film and the easy-adhesion layer is preferably 0.1 to 0.6, and more preferably 0.2 to 0.4.

B. Resin Film As the resin film constituting the polarizer protective film, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like is used. Specific examples of such thermoplastic resins include cellulose resin films such as triacetyl cellulose, polyester resin films, polyether sulfone resin films, polysulfone resin films, polycarbonate resin films, polyamide resin films, polyimides Resin film, polyolefin resin film, (meth) acrylic resin film, cyclic polyolefin resin film (norbornene resin film), polyarylate resin film, polystyrene resin film, polyvinyl alcohol resin film, and mixtures thereof Is mentioned. In the present invention, it is particularly preferable to use a (meth) acrylic resin film.

  The (meth) acrylic resin film includes a (meth) acrylic resin. The (meth) acrylic resin film is obtained, for example, by molding a molding material containing a resin component containing a (meth) acrylic resin as a main component by extrusion molding.

  As said (meth) acrylic-type resin, Tg (glass transition temperature) becomes like this. Preferably it is 115 degreeC or more, More preferably, it is 120 degreeC or more, More preferably, it is 125 degreeC or more, Most preferably, it is 130 degreeC or more. The said (meth) acrylic-type resin film can become the thing excellent in durability by including (meth) acrylic-type resin whose Tg (glass transition temperature) is 115 degreeC or more as a main component. Although the upper limit of Tg of the said (meth) acrylic-type resin is not specifically limited, From viewpoints of a moldability etc., Preferably it is 170 degrees C or less.

  Any appropriate (meth) acrylic resin can be adopted as the (meth) acrylic resin. For example, poly (meth) acrylic acid ester such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylic acid ester copolymer, methyl methacrylate-acrylic acid ester -(Meth) acrylic acid copolymer, (meth) acrylic acid methyl-styrene copolymer (MS resin, etc.), polymer having an alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl methacrylate copolymer) And methyl methacrylate- (meth) acrylate norbornyl copolymer). Preferably, C1-6 alkyl poly (meth) acrylates, such as poly (meth) acrylate methyl, are mentioned. More preferably, a methyl methacrylate resin containing methyl methacrylate as a main component (50 to 100% by weight, preferably 70 to 100% by weight) is used.

  Specific examples of the (meth) acrylic resin include, for example, Acrypet VH and Acrypet VRL20A manufactured by Mitsubishi Rayon Co., Ltd., and a high Tg (meth) acrylic resin obtained by intramolecular crosslinking or intramolecular cyclization reaction. It is done.

  In the present invention, the (meth) acrylic resin has a (meth) acrylic resin having a glutaric anhydride structure and a lactone ring structure in that it has high heat resistance, high transparency, and high mechanical strength. (Meth) acrylic resins and (meth) acrylic resins having a glutarimide structure are preferred.

  As the (meth) acrylic resin having a glutaric anhydride structure, the glutaric anhydride structure described in JP-A-2006-283013, JP-A-2006-335902, JP-A-2006-274118, or the like is used. The (meth) acrylic resin which has is mentioned.

  Examples of the (meth) acrylic resin having a lactone ring structure include JP 2000-230016, JP 2001-151814, JP 2002-120326, JP 2002-254544, and JP 2005. Examples thereof include (meth) acrylic resins having a lactone ring structure described in Japanese Patent No. 146084.

  Examples of the (meth) acrylic resin having a glutarimide structure include JP-A-2006-309033, JP-A-2006-317560, JP-A-2006-328329, JP-A-2006-328334, and JP-A-2006. No. 337491, JP-A 2006-337492, JP-A 2006-337493, JP-A 2006-337569, JP-A 2007-009182, etc. Resin.

  The content of the (meth) acrylic resin in the (meth) acrylic resin film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, particularly preferably. 70 to 97% by weight. When the content of the (meth) acrylic resin in the (meth) acrylic resin film is less than 50% by weight, the high heat resistance and high transparency inherent in the (meth) acrylic resin cannot be sufficiently reflected. There is a fear.

  The content of the (meth) acrylic resin in the molding material used for molding the (meth) acrylic resin film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, and still more preferably 60. It is -98 weight%, Most preferably, it is 70-97 weight%. When the content of the (meth) acrylic resin in the molding material used when molding the (meth) acrylic resin film is less than 50% by weight, the (meth) acrylic resin originally has high heat resistance, High transparency may not be fully reflected.

  The (meth) acrylic resin film may contain other thermoplastic resins in addition to the (meth) acrylic resin. Examples of other thermoplastic resins include olefin polymers such as polyethylene, polypropylene, ethylene-propylene copolymer, poly (4-methyl-1-pentene); vinyl chloride, vinylidene chloride, chlorinated vinyl resins, and the like. Vinyl halide polymers; acrylic polymers such as polymethyl methacrylate; styrene polymers such as polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene block copolymer Polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate; polyamides such as nylon 6, nylon 66 and nylon 610; polyacetals; polycarbonates; polyphenylene oxides; ; Polyether ether ketone; polysulfones; polyethersulfones; polyoxyethylene benzylidene alkylene; polyamideimide; polybutadiene rubber, rubber-like polymer such as ABS resin or ASA resin containing an acrylic rubber.

  The content ratio of the other thermoplastic resin in the (meth) acrylic resin film is preferably 0 to 50% by weight, more preferably 0 to 40% by weight, still more preferably 0 to 30% by weight, and particularly preferably 0 to 20%. % By weight.

  The (meth) acrylic resin film may contain an additive. Examples of additives include hindered phenol-based, phosphorus-based and sulfur-based antioxidants; light-resistant stabilizers, weather-resistant stabilizers, heat stabilizers and other stabilizers; reinforcing materials such as glass fibers and carbon fibers; phenyls UV absorbers such as salicylate, (2,2′-hydroxy-5-methylphenyl) benzotriazole, 2-hydroxybenzophenone; near infrared absorbers; tris (dibromopropyl) phosphate, triallyl phosphate, antimony oxide, etc. Flame retardants; Antistatic agents such as anionic, cationic and nonionic surfactants; Colorants such as inorganic pigments, organic pigments and dyes; Organic fillers and inorganic fillers; Resin modifiers; Organic fillers and inorganic fillers Plasticizer; Lubricant; Antistatic agent; Flame retardant; Retardation reducing agent and the like.

  The content of the additive in the (meth) acrylic resin film is preferably 0 to 5% by weight, more preferably 0 to 2% by weight, and still more preferably 0 to 0.5% by weight.

  Although it does not specifically limit as a manufacturing method of a (meth) acrylic-type resin film, For example, (meth) acrylic-type resin and other polymers, additives, etc. are enough with arbitrary appropriate mixing methods. It is possible to form a film from the thermoplastic resin composition by mixing it in advance. Alternatively, the (meth) acrylic resin and other polymers, additives, and the like may be made into separate solutions and mixed to form a uniform mixed solution, and then formed into a film.

  In order to produce the thermoplastic resin composition, for example, the film raw material is pre-blended with any appropriate mixer such as an omni mixer, and then the obtained mixture is extrusion kneaded. In this case, the mixer used for extrusion kneading is not particularly limited, and for example, any suitable mixer such as an extruder such as a single screw extruder or a twin screw extruder or a pressure kneader may be used. Can do.

  Examples of the film forming method include any appropriate film forming method such as a solution casting method (solution casting method), a melt extrusion method, a calendar method, and a compression molding method. Among these film forming methods, the solution casting method (solution casting method) and the melt extrusion method are preferable.

    Examples of the solvent used in the solution casting method (solution casting method) include aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic hydrocarbons such as cyclohexane and decalin; ethyl acetate and butyl acetate. Esters; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; alcohols such as methanol, ethanol, isopropanol, butanol, isobutanol, methyl cellosolve, ethyl cellosolve, and butyl cellosolve; ethers such as tetrahydrofuran and dioxane; dichloromethane , Halogenated hydrocarbons such as chloroform and carbon tetrachloride; dimethylformamide; dimethyl sulfoxide and the like. These solvents may be used alone or in combination of two or more.

  Examples of the apparatus for performing the solution casting method (solution casting method) include a drum casting machine, a band casting machine, and a spin coater.

  Examples of the melt extrusion method include a T-die method and an inflation method. The molding temperature is preferably 150 to 350 ° C, more preferably 200 to 300 ° C.

  When film-forming by the above T-die method, a T-die is attached to the tip of a known single-screw extruder or twin-screw extruder, and the film extruded into a film is wound to obtain a roll-shaped film Can do. At this time, it is possible to perform uniaxial stretching by appropriately adjusting the temperature of the winding roll and adding stretching in the extrusion direction. Also, simultaneous biaxial stretching, sequential biaxial stretching, and the like can be performed by stretching the film in a direction perpendicular to the extrusion direction.

  The (meth) acrylic resin film may be either an unstretched film or a stretched film. In the case of a stretched film, either a uniaxially stretched film or a biaxially stretched film may be used. In the case of a biaxially stretched film, either a simultaneous biaxially stretched film or a sequential biaxially stretched film may be used. In the case of biaxial stretching, the mechanical strength is improved and the film performance is improved. Even when the (meth) acrylic resin film is mixed with another thermoplastic resin, an increase in retardation can be suppressed and optical isotropy can be maintained.

  The stretching temperature is preferably in the vicinity of the glass transition temperature of the thermoplastic resin composition that is the film raw material, and specifically, preferably (glass transition temperature-30 ° C) to (glass transition temperature + 100 ° C), more preferably. Is within the range of (glass transition temperature−20 ° C.) to (glass transition temperature + 80 ° C.). If the stretching temperature is less than (glass transition temperature-30 ° C.), a sufficient stretching ratio may not be obtained. On the other hand, if the stretching temperature exceeds (glass transition temperature + 100 ° C.), the resin composition may flow, and stable stretching may not be performed.

  The draw ratio defined by the area ratio is preferably 1.1 to 25 times, more preferably 1.3 to 10 times. There exists a possibility that it may not lead to the improvement of the toughness accompanying extending | stretching that a draw ratio is less than 1.1 times. When the draw ratio exceeds 25 times, there is a possibility that the effect of increasing the draw ratio is not recognized.

  The stretching speed is unidirectional, preferably 10 to 20,000% / min, more preferably 100 to 10,000% / min. When the stretching speed is less than 10% / min, it takes time to obtain a sufficient stretching ratio, and the production cost may increase. If the stretching speed exceeds 20,000% / min, the stretched film may be broken.

  The (meth) acrylic resin film can be subjected to a heat treatment (annealing) or the like after the stretching treatment in order to stabilize its optical isotropy and mechanical properties. Arbitrary appropriate conditions can be employ | adopted for the conditions of heat processing.

  The thickness of the (meth) acrylic resin film is preferably 5 to 200 μm, more preferably 10 to 100 μm. When the thickness is less than 5 μm, not only the strength is lowered, but also when the durability test of the polarizing film is performed, there is a possibility that the crimp is increased. When the thickness exceeds 200 μm, not only the transparency is lowered, but also the moisture permeability becomes small, and when a water-based adhesive is used, there is a possibility that the drying rate of water as the solvent becomes slow.

  The surface tension of the (meth) acrylic resin film is preferably 40 mN / m or more, more preferably 50 mN / m or more, and still more preferably 55 mN / m or more. When the surface wetting tension is at least 40 mN / m or more, the adhesive strength between the (meth) acrylic resin film and the polarizer is further improved. Any suitable surface treatment can be applied to adjust the surface wetting tension. Examples of the surface treatment include corona discharge treatment, plasma treatment, ozone spraying, ultraviolet irradiation, flame treatment, and chemical treatment. Of these, corona discharge treatment and plasma treatment are preferable.

(Polarizing film)
As for the polarizing film which concerns on this invention, the polarizer protective film is laminated | stacked on the polarizer from the side in which the easily bonding layer was formed through the adhesive bond layer. Specifically, a polarizer, an adhesive layer, and a polarizer protective film are laminated in this order, and the polarizer is disposed on the easily adhesive layer side of the polarizer protective film. In the polarizing film which concerns on this invention, you may laminate | stack a polarizer protective film on both surfaces through an adhesive layer not only on one surface of a polarizer.

C. Polarizer Any appropriate polarizer may be adopted as the polarizer according to the purpose. For example, dichroic substances such as iodine and dichroic dyes are adsorbed on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. And polyene-based oriented films such as a uniaxially stretched product, a polyvinyl alcohol dehydrated product and a polyvinyl chloride dehydrochlorinated product. Among these, a polarizer obtained by adsorbing a dichroic substance such as iodine on a polyvinyl alcohol film and uniaxially stretching is particularly preferable because of its high polarization dichroic ratio. The thickness of these polarizers is not particularly limited, but is generally about 1 to 80 μm.

  A polarizer uniaxially stretched by adsorbing iodine to a polyvinyl alcohol film can be produced by, for example, dyeing polyvinyl alcohol in an aqueous solution of iodine and stretching it 3 to 7 times the original length. . If necessary, it may contain boric acid, zinc sulfate, zinc chloride or the like, or may be immersed in an aqueous solution such as potassium iodide. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing.

  By washing the polyvinyl alcohol film with water, not only can the surface of the polyvinyl alcohol film be cleaned and the anti-blocking agent can be washed, but also the effect of preventing unevenness such as uneven dyeing can be obtained by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

D. Adhesive Layer Any appropriate adhesive can be adopted as the adhesive forming the adhesive layer. Preferably, the adhesive layer is formed from an adhesive composition containing a polyvinyl alcohol-based resin.

  Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol resins and acetoacetyl group-containing polyvinyl alcohol resins. Preferably, it is an acetoacetyl group-containing polyvinyl alcohol resin. This is because the adhesion between the polarizer and the (meth) acrylic resin film can be further improved and the durability can be improved.

  Examples of the polyvinyl alcohol-based resin include a saponified product of polyvinyl acetate, a derivative of the saponified product; a saponified product of a copolymer with vinyl acetate and a monomer having copolymerizability; Examples thereof include modified polyvinyl alcohols that have been converted into ethers, ethers, grafts, or phosphoric esters. Examples of the monomer include unsaturated carboxylic acids such as (anhydrous) maleic acid, fumaric acid, crotonic acid, itaconic acid, and (meth) acrylic acid, and esters thereof; α-olefins such as ethylene and propylene; (Meth) allylsulfonic acid (soda), sulfonic acid soda (monoalkylmalate), disulfonic acid soda alkylmalate, N-methylolacrylamide, acrylamide alkylsulfonic acid alkali salt, N-vinylpyrrolidone, N-vinylpyrrolidone derivatives, etc. Can be mentioned. These resins can be used alone or in combination of two or more.

  The average degree of polymerization of the polyvinyl alcohol-based resin is preferably about 100 to 5000, and more preferably 1000 to 4000, from the viewpoint of adhesiveness. The average saponification degree is preferably about 85 to 100 mol%, more preferably 90 to 100 mol% from the viewpoint of adhesiveness.

  The acetoacetyl group-containing polyvinyl alcohol resin can be obtained, for example, by reacting a polyvinyl alcohol resin and diketene by an arbitrary method. As a specific example, a method in which diketene is added to a dispersion in which a polyvinyl alcohol resin is dispersed in a solvent such as acetic acid; diketene is added to a solution in which the polyvinyl alcohol resin is dissolved in a solvent such as dimethylformamide or dioxane. A method of directly contacting a diketene gas or liquid diketene with a polyvinyl alcohol resin.

  The degree of acetoacetyl group modification of the acetoacetyl group-containing polyvinyl alcohol resin is typically 0.1 mol% or more, preferably about 0.1 to 40 mol%, more preferably 1 to 20%, particularly Preferably it is 2-7 mol%. If it is less than 0.1 mol%, the water resistance may be insufficient. If it exceeds 40 mol%, the effect of improving water resistance is small. The degree of acetoacetyl group modification is a value measured by NMR.

  The adhesive composition can include a cross-linking agent. Arbitrary appropriate crosslinking agents can be employ | adopted as a crosslinking agent. A compound having at least two functional groups reactive with the polyvinyl alcohol resin is preferable. For example, alkylene diamines having two alkylene groups and two amino groups such as ethylene diamine, triethylene diamine and hexamethylene diamine; tolylene diisocyanate, hydrogenated tolylene diisocyanate, trimethylolpropane tolylene diisocyanate adduct, triphenylmethane triisocyanate, methylene bis (Isocyanates such as 4-phenylmethane triisocyanate, isophorone diisocyanate and ketoxime block product or phenol block product thereof; ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin di or triglycidyl ether, 1,6-hexane Diol diglycidyl ether, trimethylolpropane triglycidyl ether, jig Epoxys such as sidylaniline and diglycidylamine; monoaldehydes such as formaldehyde, acetaldehyde, propionaldehyde, and butyraldehyde; Aldehydes: Aminoformaldehyde resins such as methylol urea, methylol melamine, alkylated methylol urea, alkylated methylolated melamine, acetoguanamine, condensates of benzoguanamine and formaldehyde; sodium, potassium, magnesium, calcium, aluminum, iron, nickel And salts of divalent metals such as trivalent metals and oxides thereof, among which amino-formaldehyde resins and dialaldehydes. S is preferably an amino -.. Is preferably a compound having a methylol group as a formaldehyde resin, the dialdehydes are preferred glyoxal Of these compounds having a methylol group is preferable, and methylol melamine is particularly preferred.

  The blending amount of the crosslinking agent can be appropriately set according to the type of the polyvinyl alcohol resin. Typically, it is about 10 to 60 parts by weight, preferably 20 to 50 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin. This is because the adhesiveness can be excellent. In addition, when there are many compounding quantities of a crosslinking agent, reaction of a crosslinking agent advances in a short time, and there exists a tendency for an adhesive agent to gelatinize. As a result, the usable time (pot life) as an adhesive becomes extremely short, and industrial use may be difficult.

  The adhesive composition may include a metal compound colloid. The metal compound colloid can be one in which metal compound fine particles are dispersed in a dispersion medium, and can be electrostatically stabilized due to mutual repulsion of the same kind of charge of the fine particles, and can have permanent stability. . By including such a metal compound colloid, for example, an adhesive composition having excellent stability can be obtained even when the amount of the crosslinking agent is large.

  The average particle diameter of the fine particles forming the metal compound colloid can be any appropriate value as long as it does not adversely affect optical characteristics such as polarization characteristics. Preferably it is 1-100 nm, More preferably, it is 1-50 nm. This is because the fine particles can be uniformly dispersed in the adhesive layer, the adhesion can be ensured, and the occurrence of knick defects can be suppressed. “Knick defect” means light leakage.

  Any appropriate compound can be adopted as the metal compound. For example, metal oxides such as alumina, silica, zirconia and titania; metal salts such as aluminum silicate, calcium carbonate, magnesium silicate, zinc carbonate, barium carbonate and calcium phosphate; minerals such as celite, talc, clay and kaolin It is done. As will be described later, a metal compound colloid having a positive charge is preferably used in the present invention. Examples of the metal compound include alumina and titania, and alumina is particularly preferable.

  The metal compound colloid is typically present in the form of a colloidal solution dispersed in a dispersion medium. Examples of the dispersion medium include water and alcohols. The solid content concentration in the colloidal solution is typically about 1 to 50% by weight, preferably 1 to 30% by weight. The colloidal solution can contain acids such as nitric acid, hydrochloric acid, acetic acid as stabilizers.

  The compounding amount of the metal compound colloid (solid content) is preferably 200 parts by weight or less, more preferably 10 to 200 parts by weight, still more preferably 20 to 175 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin. Most preferably, it is 30-150 weight part. This is because the occurrence of knick defects can be suppressed while ensuring the adhesiveness.

  The adhesive composition includes a coupling agent such as a silane coupling agent and a titanium coupling agent, various tackifiers, an ultraviolet absorber, an antioxidant, a heat stabilizer, a hydrolysis stabilizer, and the like. May be included.

  The form of the adhesive composition is preferably an aqueous solution (resin solution). The resin concentration is preferably 0.1 to 15% by weight, more preferably 0.5 to 10% by weight, from the viewpoints of coatability and storage stability. The viscosity of the resin solution is preferably 1 to 50 mPa · s. In the case where the metal compound colloid is included, the occurrence of nick defects can be effectively suppressed even in the low viscosity range of 1 to 20 mPa · s. The pH of the resin solution is preferably 2 to 6, more preferably 2.5 to 5, further preferably 3 to 5, and most preferably 3.5 to 4.5. Usually, the surface charge of the metal compound colloid can be controlled by adjusting the pH. The surface charge is preferably a positive charge. By having a positive charge, generation of nick defects can be further suppressed. The surface charge can be confirmed, for example, by measuring the zeta potential with a zeta potential measuring device.

  Arbitrary appropriate methods can be employ | adopted for the preparation method of the said resin solution. When the crosslinking agent and the metal compound colloid are included, for example, a method of blending the metal compound colloid with a polyvinyl alcohol resin and a crosslinking agent mixed in advance and adjusted to an appropriate concentration can be mentioned. Moreover, after mixing a polyvinyl alcohol-type resin and a metal compound colloid, a crosslinking agent can also be mixed considering the time of use etc. The concentration of the resin solution may be adjusted after preparing the resin solution.

  The thickness of the adhesive layer formed from the adhesive composition can be set to any appropriate value depending on the composition of the adhesive composition and the like. The thickness is preferably 10 to 300 nm, more preferably 10 to 200 nm, and particularly preferably 20 to 150 nm. It is because sufficient adhesive force can be obtained.

(Method for producing polarizer protective film)
Arbitrary appropriate methods can be employ | adopted as a manufacturing method of the polarizer protective film of this invention. Hereinafter, one embodiment will be described. For example, the easy adhesion layer is formed in advance on one side of a resin film, for example, a (meth) acrylic resin film. The easy-adhesion layer is typically formed by applying the easy-adhesive composition to one side of a (meth) acrylic resin film and drying it. Any appropriate method can be adopted as a method for applying the easy-adhesive composition. Examples thereof include a bar coating method, a roll coating method, a gravure coating method, a rod coating method, a slot orifice coating method, a curtain coating method, and a fountain coating method. The drying temperature is typically 50 ° C. or higher, preferably 90 ° C. or higher, more preferably 110 ° C. or higher. By setting the drying temperature in such a range, a polarizing film excellent in color resistance (particularly under high temperature and high humidity) can be provided. The drying temperature is preferably 200 ° C. or lower, more preferably 180 ° C. or lower.

As described above, at least one side of the (meth) acrylic resin film (for example, the side on which the easy adhesion layer is formed) can be subjected to surface treatment. In this case, surface treatment is performed before forming the easy-adhesion layer. The surface treatment is preferably corona discharge treatment or plasma treatment. By performing the corona discharge treatment, the adhesion and adhesion between the polarizer and the (meth) acrylic resin film can be further improved. The corona discharge treatment is performed under any appropriate conditions. For example, the corona discharge electron irradiation amount is preferably 50 to 150 W / m ² / min, and more preferably 70 to 100 W / m ² / min.

  In addition, when the said (meth) acrylic-type resin film is a stretched film, the said extending | stretching process may be performed before formation of an easily bonding layer, and may be performed after formation of an easily bonding layer. Preferably, the easy-adhesive composition is applied to the (meth) acrylic resin film and then stretched. This is because the film stretching process and the easy-adhesive composition drying can be performed simultaneously.

  The polarizing film of the present invention is typically produced by laminating the polarizer protective film and the polarizer via an adhesive layer. Here, a polarizer protective film is laminated | stacked so that the easily bonding layer may become a polarizer side. Specifically, after applying the adhesive composition on one side of either the polarizer or the polarizer protective film, the polarizer and the polarizer protective film are bonded together and dried. Examples of the method for applying the adhesive composition include a roll method, a spray method, and an immersion method. Moreover, when an adhesive composition contains a metal compound colloid, it applies so that the thickness after drying may become larger than the average particle diameter of a metal compound colloid. The drying temperature is typically 5 to 150 ° C, preferably 30 to 120 ° C. The drying time is typically 120 seconds or longer, preferably 300 seconds or longer.

(Image display device)
The image display device of the present invention has the polarizing film of the present invention. Specific examples of the image display device include a self-luminous display device such as an electroluminescence (EL) display, a plasma display (PD), and a field emission display (FED), and a liquid crystal display device. The liquid crystal display device includes a liquid crystal cell and the polarizing film disposed on at least one side of the liquid crystal cell.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples. In addition, the evaluation method of an optical characteristic is as follows.

<Optical characteristics>
The in-plane retardation Δnd and the thickness direction retardation Rth were measured using KOBRA-WPR manufactured by Oji Scientific Instruments. Visible light transmittance (total light transmittance) was measured using NDH-1001DP manufactured by Nippon Denshoku Industries Co., Ltd.

Example 1
(Production of polarizer)
A 30 μm thick polyvinyl alcohol film was immersed in warm water at 28 ° C. for 60 seconds to swell. Next, it was immersed in an aqueous solution containing iodine and potassium iodide (weight ratio 1:10) and dyed so as to have a predetermined single body transmittance while stretching up to 3.3 times. Thereafter, the film was immersed in an aqueous solution containing 3% by weight boric acid and 2% by weight potassium iodide for 10 seconds and stretched in an aqueous solution containing 4% by weight boric acid and 3% by weight potassium iodide at 60 ° C. Was stretched to a total of 6.0 times. Thereafter, the obtained stretched film was immersed in an aqueous solution containing 5% by weight of potassium iodide for 10 seconds and dried in an oven at 40 ° C. for 3 minutes to obtain a polarizer having a thickness of 12 μm.

(Production of (meth) acrylic resin film)
In the following general formula (1), R ¹ is a hydrogen atom and R ² and R ³ are methyl groups. A (meth) acrylic resin having a lactone ring structure {copolymerization monomer weight ratio = methyl methacrylate / 2- (hydroxy Methyl) methyl acrylate = 8/2, lactone cyclization rate of about 100%, lactone ring structure content 19.4%, weight average molecular weight 133000, melt flow rate 6.5 g / 10 min (240 ° C., 10 kgf), A mixture of 90 parts by weight of Tg 131 ° C. and 10 parts by weight of acrylonitrile-styrene (AS) resin {Toyo AS AS20, manufactured by Toyo Styrene Co., Ltd .; Tg 127 ° C.] was fed to a twin screw extruder at about 280 ° C. It was melt-extruded into a sheet to obtain a (meth) acrylic resin sheet having a lactone ring structure with a thickness of 110 μm. This unstretched sheet was stretched 2.0 times in length and 2.4 times in width under a temperature condition of 160 ° C. to give a (meth) acrylic resin film (thickness: 40 μm, in-plane retardation Δnd: 0.8 nm , Thickness direction retardation Rth: 1.5 nm).

(Corona discharge treatment)
One side of the (meth) acrylic resin film obtained above was subjected to corona discharge treatment (corona discharge electron irradiation amount: 77 W / m ² / min).

(Preparation of polarizer protective film)
Polyester urethane (Daiichi Kogyo Seiyaku Co., Ltd., trade name: Superflex 210, solid content: 33%) 4.75 g, pure water 65.0 g, and 1 wt% ammonia water 0.5 g were mixed and stirred, and then a crosslinking agent (Oxazoline-containing polymer, manufactured by Nippon Shokubai Co., Ltd., trade name: Epocross WS-700, solid content: 25%) 1.2 g, and colloidal silica (manufactured by Fuso Chemical Industries, Quattron PL-3, solid content: 20% by weight) 8 g and 0.25 g of an isocyanuric group-containing silane coupling agent (KBM-9659, manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed and further stirred to obtain an easy-adhesive composition (1-B). The obtained easy-adhesive composition (1-B) was subjected to corona discharge treatment on the corona discharge treatment surface of the (meth) acrylic resin film so that the thickness after drying was 100 nm. It was applied in 3). Thereafter, the (meth) acrylic resin film was put into a hot air dryer (115 ° C.), and the easy-adhesive composition (1-B) was dried for about 10 minutes to form an easy-adhesive layer.

(Second polarizer protective film)
A triacetylcellulose film having a thickness of 80 μm was immersed in a 10% aqueous sodium hydroxide solution (60 ° C.) for 30 seconds to saponify, and then washed with water for 60 seconds to obtain a second polarizer protective film.

(Preparation of adhesive composition)
An acetoacetyl group-containing polyvinyl alcohol resin (average polymerization degree: 1200, saponification degree: 98.5 mol%, acetoacetyl group modification degree: 5 mol%) is 100 parts by weight, and 20 parts by weight of methylolmelamine is 30 ° C. It was dissolved in pure water under temperature conditions to obtain an aqueous solution with a solid content concentration of 0.5%. The obtained aqueous solution was used as an adhesive composition under a temperature condition of 30 ° C.

(Preparation of polarizing film)
30 minutes after the preparation of the adhesive composition, the adhesive composition was applied to the easy-adhesion layer side of the polarizer protective film so that the thickness after drying was 50 nm. Similarly, the adhesive composition was applied to one side of the second polarizer protective film. After that, the polarizer protective film and the second polarizer protective film are laminated on each side of the polarizer through the adhesive composition using a small laminator, and put into a hot air dryer (80 ° C.). The film was dried for 5 minutes to obtain a polarizing film.

(Example 2)
Other than using an easy-adhesive composition (1-C) obtained by blending an acetoacetyl group-containing silane coupling agent (A-100, manufactured by Soken Chemical Co., Ltd.) instead of the isocyanuric group-containing silane coupling agent Obtained a polarizing film in the same manner as in Example 1.

(Example 3)
Easy-adhesive composition obtained by blending an acid anhydride group-containing silane coupling agent (3-trimethoxysilylpropylsuccinic anhydride, manufactured by Shin-Etsu Chemical Co., Ltd.) instead of the isocyanuric group-containing silane coupling agent ( A polarizing film was obtained in the same manner as in Example 2 except that 1-D) was used.

Example 4
Other than using the easy-adhesive composition (1-E) obtained by blending an aqueous dispersion of a carboxyl group-containing polymer (AC-10L, manufactured by Toagosei Co., Ltd.) instead of the isocyanuric group-containing silane coupling agent Obtained a polarizing film in the same manner as in Example 3.

(Comparative Example 1)
Polyester urethane (Daiichi Kogyo Seiyaku Co., Ltd., trade name: Superflex 210, solid content: 33%) 5.0 g, pure water 65.0 g, and 1 wt% ammonia water 0.5 g are mixed and stirred, and then a crosslinking agent. (Oxazoline-containing polymer, manufactured by Nippon Shokubai Co., Ltd., trade name: Epocross WS-700, solid content: 25%) 1.2 g, and colloidal silica (manufactured by Fuso Chemical Industries, Quattron PL-3, solid content: 20% by weight) 8 g was mixed and further stirred to obtain an easy-adhesive composition (1-A). The obtained easy-adhesive composition (1-A) was subjected to corona discharge treatment on the corona discharge treatment surface of the (meth) acrylic resin film so that the thickness after drying was 100 nm. It was applied in 3). Thereafter, the (meth) acrylic resin film was put into a hot air dryer (115 ° C.), and the easy-adhesive composition (1-A) was dried for about 10 minutes to form an easy-adhesion layer.

  A polarizing film was obtained in the same manner as in Example 1 using this (meth) acrylic resin film, the second polarizer protective film, and the adhesive composition.

  The following evaluation was performed about the polarizer protective film and polarizing film obtained by each Example and the comparative example. The evaluation results are summarized in Table 1.

(Adhesive strength of polarizing film (adhesive strength between polarizer and (meth) acrylic resin film))
A sample piece having a size of 15 mm × 70 mm was cut out from the polarizing film obtained above so that the absorption axis was a long side, the surface on the acrylic resin film side was subjected to adhesive processing, and attached to a glass plate. After that, a cutter blade is inserted between the acrylic resin film of the polarizing film and the polarizer, and a part of the cutter is peeled off. The end is gripped, and the acrylic is acrylic at a 90 ° angle at a speed of 1000 mm / min in the long side direction. The system resin film and the polarizer were peeled, and the adhesive force was measured. When the adhesive force was 2.0 N / 15 mm or more, it was evaluated as “◯”, and when the adhesive force was less than 2.0 N / 15 mm, it was evaluated as “x”.

(Haze of first polarizer protective film)
The haze of the 1st polarizer protective film used for the Example and the comparative example was measured. When the haze was 0.7 or less, it was evaluated as “◯”, when the haze was 0.8 to 1.2, “Δ”, and when the haze was 1.3 or more, “x”.

(Coating properties of easy-adhesive composition)
The applicability | paintability to the (meth) acrylic-type resin film of the easily adhesive composition used for the Example and the comparative example was confirmed. Specifically, when repelling is observed in the coating film visually after 3 seconds after coating with a bar coater, △, when repelling is observed in the coating film visually after 10 seconds When repelling was observed for a longer time or when repelling did not occur, it was rated as ○.

(Optical reliability (change in single transmittance and degree of polarization))
The polarizing film obtained above is subjected to corona treatment on the acrylic resin film side, and a 20 μm-thick butyl acrylate pressure-sensitive adhesive is bonded to the corona-treated surface to absorb the polarizing film in a size of 50 mm × 25 mm. A sample was cut out so that the axis was 90 ° with respect to the long side, the release film on the butyl acrylate-based pressure-sensitive adhesive side was peeled off, and bonded to a slide glass to prepare a measurement sample. Using an integrating sphere type transmittance measuring machine (Murakami Color Research Laboratory Co., Ltd .: DOT-3C), initial single transmittance (%) and initial polarization degree were measured. These measurement samples were put in an environment of 85 ° C. and a relative humidity of 85% for 240 hours and then taken out. After that, the single transmittance and the degree of polarization were measured in the same manner as described above. The degree of polarization after aging was used. Then, the change amount of the single transmittance (= single transmittance after time-initial single transmittance) and the change amount of polarization degree (= polarization degree after time-initial polarization degree) were calculated.

As is apparent from Table 1, in the examples, the adhesive strength was 1.5 N / 15 mm or more, which was good, whereas in the comparative example, the adhesive strength was less than 1.5 N / 15 mm.

Claims (11)

  (A) component consisting of at least one selected from the group consisting of an acid anhydride group-containing silane coupling agent, an acetoacetyl group-containing silane coupling agent, an isocyanuric group-containing silane coupling agent, and a carboxyl group-containing polymer, and urethane An easy-adhesive composition comprising a component (B) made of a resin.   Furthermore, the easily adhesive composition of Claim 1 containing microparticles | fine-particles.   The easy-adhesive composition according to claim 1 or 2, wherein the urethane resin has a carboxyl group.   The easy-adhesive composition according to claim 2 or 3, wherein the fine particles are colloidal silica.   A polarizer protective film comprising an easy-adhesion layer formed of the easy-adhesive composition according to claim 1 on at least one surface of a resin film.   The polarizer protective film according to claim 5, wherein the resin film is a (meth) acrylic resin film.   The polarizer protective film according to claim 6, wherein the (meth) acrylic resin film has a lactone ring structure.   The polarizer protective film according to claim 5, wherein a corona discharge treatment or a plasma treatment is performed on a side of the resin film on which the easy adhesion layer is formed.   The polarizing film by which the polarizer protective film in any one of Claims 5-8 was laminated | stacked on the polarizer from the side in which the said easily bonding layer was formed through the adhesive bond layer.   The polarizing film according to claim 9, wherein the adhesive layer is formed of a polyvinyl alcohol-based adhesive. An image display apparatus provided with the polarizing film of Claim 9 or 10.