JP2013242510A - Optical film and use thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical film that is configured of an acrylic resin film having an easy adhesion layer formed on the surface thereof, and has improved adhesion to a functional coating layer.SOLUTION: An optical film includes an acrylic resin film made of an acrylic resin (A), and an easy adhesion layer (a) containing a polyester-acrylic composite resin (B). The optical film of the present invention is suitable for use for various protective films including a polarizer protective film, a retardation film, and a polarizing plate, which are used for an image display device such as a liquid crystal display (LCD).

Description

  The present invention relates to an optical film and use thereof, and more specifically, an optical film having an acrylic resin film used for a liquid crystal display device, an organic electroluminescence display device, and the like, and an easy adhesion layer containing a polyester-acrylic composite resin. The present invention relates to a film, and a polarizer protective film, a polarizing plate and an image display device using the film.

  An acrylic resin containing a (meth) acrylic polymer typified by polymethyl methacrylate (PMMA) is excellent in optical properties such as light transmittance and excellent in balance between mechanical strength, molding processability and surface hardness. For this reason, acrylic resins are widely used as transparent materials in various industrial products such as automobiles and home appliances. In recent years, there are an increasing number of cases in which acrylic resins are used for optical applications. In particular, the application of acrylic resin to an optical film incorporated in an image display device such as a liquid crystal display device (LCD), a plasma display panel (PDP), or an organic EL display device (OELD) has been promoted.

  For example, a polarizer protective film which is a kind of optical film is usually used in an image display device in a state of a polarizing plate laminated with a polarizer. The polarizing plate usually has a configuration including a polarizer and a polarizer protective film bonded to at least one surface of the polarizer via an adhesive layer, and the outermost layer has functionality such as a hard coat layer. A coating layer may be laminated. Patent Document 1 discloses an optical film using such an acrylic resin film having a functional coating layer.

JP 2006-096960 A

  Patent Document 1 discloses an acrylic resin film having various functional coating layers. The optical functional thermoplastic resin described in Patent Document 1 is laminated and coated with the various functional coating layers. The method and the method of laminating | stacking the member by which the functional coating layer was coated on the optical planar thermoplastic resin molded object via an adhesive or an adhesive agent are disclosed.

  However, there is a problem that the adhesion between the acrylic resin film and the functional coating layer is insufficient.

  The present invention has been made in view of the above problems, and is an optical film composed of an acrylic resin film having an easy-adhesion layer formed on the surface thereof, and a functional coating layer typified by a hard coat layer; It aims at providing the optical film excellent in adhesiveness.

  In order to solve the above-mentioned problems, the present inventor uses a known easy-adhesion composition having a good compatibility with a polyvinyl alcohol (PVA) -based adhesive for bonding an optical film and a polarizer. Various studies were made as to whether the problems of the invention could not be solved. As a result, it was found that the adhesion between the acrylic resin film and the functional coating layer was greatly improved by using an easy-adhesion layer containing a polyester-acrylic composite resin, and the present invention was completed. That is, the present invention includes the following configurations.

  The optical film of the present invention is an optical film having an acrylic resin film made of an acrylic resin (A) and an easy adhesion layer (a) containing a polyester-acrylic composite resin (B).

  In the optical film of the present invention, the polyester-acrylic composite resin (B) preferably has an epoxy group.

  In the optical film of the present invention, it is more preferable that the polyester-acrylic composite resin (B) further has a carboxyl group.

  In the optical film of the present invention, the easy adhesion layer (a) preferably contains fine particles, and the average primary particle diameter of the fine particles contained in the easy adhesion layer (a) is 300 nm or less, and the easy adhesion layer ( The particle size distribution of the fine particles contained in a) is more preferably 1.0 to 1.4.

  The optical film of the present invention preferably has a functional coating layer on the easy adhesion layer (a) containing the polyester-acrylic composite resin (B). That is, the easy adhesion layer (a) containing the polyester-acrylic composite resin (B) is formed on one main surface of the acrylic resin film, and the acrylic resin film side of the easy adhesion layer (a). It is preferable that a functional coating layer is formed on the surface facing the surface.

  As for the optical film of this invention, it is preferable that an acrylic resin film further has an easily bonding layer (b) in the surface on the opposite side to the said easily bonding layer (a). That is, it is preferable that the easy adhesion layer (b) is formed on the main surface of the acrylic resin film opposite to the surface on which the easy adhesion layer (a) is formed.

  In the optical film of the present invention, the easy-adhesion layer (b) is more preferably a urethane resin layer.

  In the optical film of the present invention, an adhesive layer is preferably formed on the surface of the easy-adhesion layer (b) that faces the surface on the acrylic resin film side.

  In the optical film of the present invention, the acrylic resin film preferably contains a (meth) acrylic polymer having a ring structure in the main chain.

  In the optical film of the present invention, the ring structure is preferably at least one selected from the group consisting of a maleic anhydride structure, an N-substituted maleimide structure, a glutaric anhydride structure, a glutarimide structure, and a lactone ring structure.

  The optical film of the present invention preferably has a light transmittance at 380 nm of 30% or less.

  In the optical film of the present invention, the acrylic resin film preferably contains an ultraviolet absorber having a molecular weight of 600 or more.

  The polarizer protective film of the present invention includes the optical film of the present invention.

  The polarizing plate of the present invention includes the optical film of the present invention.

  The image display device of the present invention includes the polarizing plate of the present invention.

  The optical film concerning this invention is the structure of having an acrylic resin film which consists of an acrylic resin (A), and an easily bonding layer (a) containing a polyester-acrylic composite resin (B).

  Therefore, it is possible to provide an optical film excellent in adhesion to a functional coating layer such as a hard coat layer and having improved strength, a polarizer protective film using the same, a polarizing plate and an image display device.

The example of the 1st form of the optical film of this invention is represented. The example of the 2nd form of the optical film of this invention is represented. The example of the 3rd form of the optical film of this invention is represented. 1 represents one embodiment of a polarizing plate according to the present invention.

  Hereinafter, embodiments of the present invention will be described in detail. Unless otherwise specified in the following description, “%” means “mass%” and “part” means “part by mass”. In addition, “A to B” indicating a range indicates that the range is A or more and B or less.

  In the present specification, “resin” is a broader concept than “polymer”. The resin may be composed of, for example, one type or two or more types of polymers, and if necessary, materials other than the polymer, for example, additives such as ultraviolet absorbers, antioxidants, fillers, and compatibilizing agents. Further, it may contain a stabilizer and the like.

[1. Optical film)
The optical film concerning this invention has an acrylic resin film which consists of an acrylic resin (A), and an easily bonding layer (a) containing a polyester-acrylic composite resin (B). Hereinafter, the structure of the optical film concerning this invention is demonstrated in order of an acrylic resin film and an easily bonding layer.

(1-1. Acrylic resin film)
An acrylic resin film is a film comprised from the acrylic resin (A) containing a (meth) acrylic polymer. That is, the acrylic resin film is made of an acrylic resin (A).

  The acrylic resin film is obtained by molding the acrylic resin (A). The content of the (meth) acrylic polymer in the acrylic resin (A) is usually 30% by mass or more, preferably 50% by mass or more, more preferably 70% by mass or more, particularly preferably 90% by mass or more, and most preferably. It is 95 mass% or more. The (meth) acrylic polymer has excellent optical properties such as high light transmittance and low wavelength dependency of refractive index. For this reason, the acrylic resin (A) containing a (meth) acrylic polymer is suitable for use in an optical film.

  The (meth) acrylic polymer is a polymer having a structural unit ((meth) acrylic acid ester unit) derived from a (meth) acrylic acid ester monomer. The content of the (meth) acrylic acid ester unit in the (meth) acrylic polymer is usually 10% by mass or more, preferably 30% by mass or more, more preferably 50% by mass or more, and particularly preferably 70% by mass or more. .

  The (meth) acrylic polymer may have a ring structure in the main chain. The ring structure is obtained by, for example, copolymerizing a (meth) acrylate monomer and a monomer having a ring structure, or polymerizing a monomer group including a (meth) acrylate monomer. By proceeding with the cyclization reaction, it is introduced into the main chain of the (meth) acrylic polymer. When the polymer has a ring structure in the main chain, the polymer is a (meth) acrylic polymer if the total content of the (meth) acrylic acid ester unit and the ring structure is 50% by mass or more.

  (Meth) acrylic acid ester units are, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, t- (meth) acrylic acid t- Butyl, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, chloromethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2-hydroxy (meth) acrylate Each of ethyl, 3-hydroxypropyl (meth) acrylate, 2,3,4,5,6-pentahydroxyhexyl (meth) acrylate, and 2,3,4,5-tetrahydroxypentyl (meth) acrylate It is a structural unit derived from a monomer.

  The (meth) acrylic polymer preferably has methyl (meth) acrylate units. In this case, the optical properties and thermal stability of the finally obtained optical film are improved. The (meth) acrylic polymer may have two or more (meth) acrylic acid ester units.

  The (meth) acrylic polymer may have a structural unit other than the (meth) acrylic acid ester unit. Such structural units include, for example, styrene, vinyl toluene, α-methylstyrene, α-hydroxymethylstyrene, α-hydroxyethylstyrene, acrylonitrile, methacrylonitrile, ethylene, propylene, 4-methyl-1-pentene, acetic acid. It is a structural unit derived from each monomer of vinyl, 2-hydroxymethyl-1-butene, methyl vinyl ketone, N-vinyl pyrrolidone, and N-vinyl carbazole. The (meth) acrylic polymer may have two or more of these structural units. When the (meth) acrylic polymer has N-vinylpyrrolidone units or N-vinylcarbazole units, the degree of freedom in controlling the birefringence wavelength dispersibility in the optical film is improved. For example, in the visible light region, a retardation film exhibiting wavelength dispersibility (so-called reverse wavelength dispersibility) can be obtained as the birefringence decreases (the absolute value of the phase difference decreases) as the wavelength of light decreases.

  When a cyclic structure is introduced into the main chain by a cyclization reaction after polymerization, the (meth) acrylic polymer is formed by copolymerization of a monomer group including a monomer having a hydroxyl group and / or a carboxylic acid group. Is preferred.

  Examples of the monomer having a hydroxyl group include methyl 2- (hydroxymethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, isopropyl 2- (hydroxymethyl) acrylate, butyl 2- (hydroxymethyl) acrylate, These are methyl 2- (hydroxyethyl) acrylate, methallyl alcohol, and allyl alcohol. Examples of the monomer having a carboxylic acid group include acrylic acid, methacrylic acid, crotonic acid, 2- (hydroxymethyl) acrylic acid, and 2- (hydroxyethyl) acrylic acid.

  Two or more of these monomers may be used. These monomers become a ring structure located in the main chain of the (meth) acrylic polymer by a cyclization reaction, but it is not necessary that all of the monomers change into a ring structure during the cyclization reaction. The (meth) acrylic polymer after the cyclization reaction may have a structural unit derived from these monomers.

  The weight average molecular weight of the (meth) acrylic polymer is preferably 10,000 to 500,000, more preferably 20,000 to 400,000, and still more preferably 30,000 to 300,000.

  The (meth) acrylic polymer preferably has a ring structure in the main chain. The acrylic resin film preferably contains a (meth) acrylic polymer having a ring structure in the main chain. In this case, the heat resistance and hardness of the optical film are improved. In addition to this, the ring structure of the main chain contributes to the development of a large retardation in the acrylic resin film by stretching. This feature enables the use of the optical film of the present invention as a polarizer protective film having a retardation film or retardation film function.

  The ring structure that the (meth) acrylic polymer may have in the main chain is, for example, at least one selected from an N-substituted maleimide structure, a maleic anhydride structure, a glutarimide structure, a glutaric anhydride structure, and a lactone ring structure. It is a seed. The N-substituted maleimide structure is, for example, a cyclohexylmaleimide structure, a methylmaleimide structure, a phenylmaleimide structure, or a benzylmaleimide structure.

  From the viewpoint of the heat resistance of the optical film, the ring structure includes a lactone ring structure, a cyclic imide structure (for example, an N-alkyl-substituted maleimide structure, a glutarimide structure), and a cyclic anhydride structure (for example, a maleic anhydride structure and an anhydrous structure). Glutaric acid structure) is preferred.

  When the optical film of the present invention is a retardation film, the ring structure is preferably a lactone ring structure, a glutarimide structure, or a glutaric anhydride structure from the viewpoint of imparting a positive retardation to the film.

  The following general formula (1) shows a glutaric anhydride structure and a glutarimide structure.

In the general formula (1), R ¹ and R ² are each independently a hydrogen atom or a methyl group, and X ¹ is an oxygen atom or a nitrogen atom. When X ¹ is an oxygen atom, R ³ is not present, and when X ¹ is a nitrogen atom, R ³ is a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms, a cyclopentyl group, a cyclohexyl group, a benzyl group Or it is a phenyl group.

When X ¹ is an oxygen atom, the ring structure represented by the general formula (1) is a glutaric anhydride structure. The glutaric anhydride structure can be formed, for example, by subjecting a copolymer of (meth) acrylic acid ester and (meth) acrylic acid to dealcoholization cyclocondensation in the molecule.

When X ¹ is a nitrogen atom, the ring structure represented by the general formula (1) is a glutarimide structure. The glutarimide structure can be formed, for example, by imidizing a (meth) acrylic acid ester polymer with an imidizing agent such as methylamine.

  The following general formula (2) shows a maleic anhydride structure and an N-substituted maleimide structure.

In the general formula (2), R ⁴ and R ⁵ are each independently a hydrogen atom or a methyl group, and X ² is an oxygen atom or a nitrogen atom. When X ² is an oxygen atom, R ⁶ is not present, and when X ² is a nitrogen atom, R ⁶ is a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms, a cyclopentyl group, a cyclohexyl group, a benzyl group. Or it is a phenyl group.

When X ² is an oxygen atom, the ring structure represented by the general formula (2) is a maleic anhydride structure. The maleic anhydride structure can be formed, for example, by copolymerizing maleic anhydride and (meth) acrylic acid ester.

When X ² is a nitrogen atom, the ring structure represented by the general formula (2) is an N-substituted maleimide structure. The N-substituted maleimide structure can be formed, for example, by polymerizing an N-substituted maleimide such as phenylmaleimide and a (meth) acrylic acid ester.

  In each method for forming the ring structure exemplified in the description of the general formulas (1) and (2), all the polymers used for forming each ring structure have (meth) acrylate units as constituent units. Therefore, the resin obtained by the method is an acrylic resin.

  The lactone ring structure that the (meth) acrylic polymer may have in the main chain is not particularly limited, and may be, for example, a 4- to 8-membered ring. A ring or a 6-membered ring is preferable, and a 6-membered ring is more preferable.

  The lactone ring structure which is a 6-membered ring is, for example, the structure disclosed in Japanese Patent Application Laid-Open No. 2004-168882, but the lactone ring structure is high due to the high polymerization yield of the precursor and the cyclization condensation reaction of the precursor. The structure represented by the following general formula (3) is preferable because an acrylic resin having a ring content can be obtained and a polymer having a methyl methacrylate unit as a constituent unit can be used as a precursor.

In the general formula (3), R ⁷ , R ⁸ and R ⁹ are each independently a hydrogen atom or an organic residue having 1 to 20 carbon atoms. The organic residue may contain an oxygen atom.

  The organic residue in the general formula (3) is, for example, an alkyl group having 1 to 20 carbon atoms such as a methyl group, an ethyl group, or a propyl group, and an organic residue having 2 to 20 carbon atoms such as an ethenyl group or a propenyl group. An aromatic hydrocarbon group having 6 to 20 carbon atoms, such as a saturated aliphatic hydrocarbon group, a phenyl group, or a naphthyl group, and the alkyl group, the unsaturated aliphatic hydrocarbon group, and the aromatic hydrocarbon group are One or more hydrogen atoms may be substituted with at least one group selected from a hydroxyl group, a carboxyl group, an ether group, and an ester group.

  Although the content rate of the said ring structure except a lactone ring structure in an acrylic resin (A) is not specifically limited, For example, it is 5-90 mass%, Preferably it is 10-70 mass%, More preferably, this is 10-60 mass %, And more preferably 10 to 50% by mass.

  When the acrylic resin (A) has a lactone ring structure in the main chain, the content of the lactone ring structure in the resin is not particularly limited, but is, for example, 5 to 90% by mass, preferably 10 to 80% by mass. More preferably, it is 10-70 mass%, More preferably, it is 20-60 mass%.

  When the content of the ring structure in the acrylic resin (A) becomes transiently small, the heat resistance of the film may be lowered, and the solvent resistance and surface hardness may be insufficient. On the other hand, when the said content rate becomes transiently large, the moldability and mechanical characteristic of a film will fall.

  The (meth) acrylic polymer having a ring structure in the main chain can be formed by a known method.

  The (meth) acrylic polymer having a glutaric anhydride structure in the main chain is, for example, a polymer described in JP-A-2006-283013, JP-A-2006-335902, or JP-A-2006-274118. Yes, it can be formed by the method described in the publication.

  Examples of (meth) acrylic polymers having a glutarimide structure in the main chain include, for example, JP-A-2006-309033, JP-A-2006-317560, JP-A-2006-328329, JP-A-2006-328334, JP-A 2006-337491, JP-A 2006-337492, JP-A 2006-337493, JP-A 2006-337469, JP-A 2007-009182 It can be formed by the method described in the publication.

  The (meth) acrylic polymer having a maleic anhydride structure or an N-substituted maleimide structure in the main chain is, for example, a polymer described in JP-A-57-153008 and JP-A-2007-31537. It can be formed by the method described in the publication.

  Examples of the (meth) acrylic polymer having a lactone ring structure in the main chain include, for example, JP 2000-230016, JP 2001-151814, JP 2002-120326, JP 2002-254544, It is a polymer described in JP 2005-146084 A, and can be formed by the method described in the publication.

  The acrylic resin film may contain a thermoplastic polymer other than the (meth) acrylic polymer as long as the effect of the present invention is obtained.

  Other thermoplastic polymers include, for example, olefin polymers such as polyethylene, polypropylene, ethylene-propylene copolymer, poly (4-methyl-1-pentene); polyvinyl chloride, polyvinylidene chloride, polyvinyl chloride, etc. Styrene polymers such as vinyl halide polymer; polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene block copolymer; polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate Polyesters such as cellulose triacetate, cellulose acetate propionate, cellulose acylate such as cellulose acetate butyrate; polyamids such as nylon 6, nylon 66, nylon 610 Polyacetal; Polycarbonate; Polyphenylene oxide; Polyphenylene sulfide; Polyetheretherketone; Polysulfone; Polyethersulfone; Polyoxybenzylene; Polyamideimide; Rubber weight such as ABS resin and ASA resin blended with polybutadiene rubber or acrylic rubber Coalescence;

  The rubbery polymer preferably has a graft portion having a composition compatible with the acrylic resin (A) on the surface, and the average particle diameter of the rubbery polymer is from the viewpoint of improving transparency when used as a film. It is preferable that it is 300 nm or less, More preferably, it is 200 nm or less, More preferably, it is 150 nm or less.

  The average particle size of the rubber polymer can be measured by the same method as the method for obtaining the average primary particle size of fine particles described later.

  When the acrylic resin film is a stretched film containing a styrenic polymer, the positive phase difference exhibited by the (meth) acrylic polymer having a ring structure in the main chain is canceled by the negative phase difference exhibited by the styrenic polymer. be able to. Depending on the content of the styrenic polymer in the acrylic resin film, the optical film of the present invention which is a stretched film can be a negative retardation film or a low retardation polarizer protective film.

  When the acrylic resin film contains a styrene polymer, a styrene-acrylonitrile copolymer is preferred as the styrene polymer from the viewpoint of compatibility with the (meth) acrylic polymer. When the acrylic resin film contains ABS resin or ASA resin, depending on the content of the resin in the acrylic resin film, the optical film of the present invention which is a stretched film may be a positive or negative retardation film or a low retardation film. , The flexibility is improved.

  The content of the other thermoplastic polymer in the acrylic resin film is preferably 0 to 50% by mass, more preferably 0 to 40% by mass, further preferably 0 to 30% by mass, and particularly preferably 0 to 20% by mass. is there.

  The acrylic resin film may have an ultraviolet absorbing ability as long as the heat resistance, physical properties, and optical properties are not impaired. Specifically, a method using an ultraviolet-absorbing monomer and / or an ultraviolet-stable monomer as a monomer component when producing a (meth) acrylic polymer, an ultraviolet absorber and / or an ultraviolet stabilizer Is blended with the (meth) acrylic polymer. In addition, these methods may be used in combination as long as there is no problem in the optical film containing the acrylic resin film.

  In order to maintain the ultraviolet absorbing function, it is preferable to use an ultraviolet absorbing monomer and an ultraviolet stabilizing monomer in combination, or an ultraviolet absorber and an ultraviolet stabilizer in combination. It is also preferable to use an ultraviolet absorber and / or an ultraviolet stabilizer in combination with the ultraviolet absorbing monomer and / or the ultraviolet stabilizing monomer.

  Examples of the ultraviolet absorbing monomer include benzotriazole compounds, benzophenone compounds or triazine compounds and acrylic monomers having a polymerizable unsaturated group.

  Examples of benzotriazole compounds include 2- [2′-hydroxy-5 ′-(meth) acryloyloxymethylphenyl] -2H-benzotriazole, 2- [2′-hydroxy-5 ′-(meth) acryloyloxyethyl. Phenyl] -2H-benzotriazole, 2- [2′-hydroxy-5 ′-(meth) acryloyloxypropylphenyl] -2H-benzotriazole, 2- [2′-hydroxy-5 ′-(meth) acryloyloxyhexyl Phenyl] -2H-benzotriazole, 2- [2′-hydroxy-3′-tert-butyl-5 ′-(meth) acryloyloxyethylphenyl] -2H-benzotriazole, 2- [2′-hydroxy-5 ′ -(Β- (Meth) acryloyloxyethoxy) -3′-tert-butyl Enyl] -5-tert-butyl-2H-benzotriazole, 2- [2′-hydroxy-3′-methacrylaminomethyl-5 ′-(1 ″, 1 ″, 3 ″, 3 ″ -tetramethyl) butylphenyl ] -2H-benzotriazole and the like can be used.

  Examples of the benzophenone compounds include 2-hydroxy-4- [2- (meth) acryloyloxy] ethoxybenzophenone, 2-hydroxy-4- [2- (meth) acryloyloxy] butoxybenzophenone, 2,2 ′. -Dihydroxy-4- [2- (meth) acryloyloxy] ethoxybenzophenone, 2-hydroxy-4- [2- (meth) acryloyloxy] ethoxy-4 '-(2-hydroxyethoxy) benzophenone, and the like can be used. .

  Examples of triazine compounds include 4-diphenyl-6- [2-hydroxy-4- (2-acryloyloxyethoxy)]-s-triazine, 2,4-bis (2-methylphenyl) -6- [2-Hydroxy-4- (2-acryloyloxyethoxy)]-s-triazine, 2,4-bis (2-methoxyphenyl) -6- [2-hydroxy-4- (2-acryloyloxyethoxy)]- An s-triazine or the like can be used.

  When such an ultraviolet absorbing monomer is used, the ultraviolet absorbing monomer is preferably copolymerized in an amount of 0.1 to 25% by mass, more preferably 1 to 15% by mass based on the total monomers. Copolymerization is preferred. If the content is small, the contribution to improving weather resistance is low, and if the content is too large, the hot water resistance and solvent resistance may be reduced, or yellowing may occur.

  As the UV-stable monomer, a monomer having a polymerizable unsaturated group bonded to a hindered amine compound can be used. Specific examples include 4- (meth) acryloyloxy-2,2,6,6. -Tetramethylpiperidine, 4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4- (meth) acryloyloxy-1,2,2,6,6-pentamethylpiperidine, 4- ( (Meth) acryloylamino-1,2,2,6,6-pentamethylpiperidine, 4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 4-crotonoyloxy-2 , 2,6,6-tetramethylpiperidine, 4-crotonoylamino-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4- (me ) Acryloylamino-2,2,6,6-tetramethylpiperidine, 1- (meth) acryloyl-4-cyano-4- (meth) acryloylamino-2,2,6,6-tetramethylpiperidine, 1-crotonoyl -4-crotonoyloxy-2,2,6,6-tetramethylpiperidine and the like.

  In the case of using such a UV-stable monomer, the UV-stable monomer is preferably copolymerized in an amount of 0.1 to 25% by weight, more preferably 1 to 15% by weight of the total monomers. % Copolymerization is preferred. If the content is small, the contribution to improving weather resistance is low, and if the content is too large, the hot water resistance and solvent resistance may be reduced, or yellowing may occur.

  Examples of the ultraviolet absorber include benzophenone compounds, salicylate compounds, benzoate compounds, triazole compounds, and triazine compounds.

  Examples of the benzophenone compounds include 2,4-dihydroxybenzophenone, 4-n-octyloxy-2-hydroxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2-hydroxy-4-n-octyloxy. Examples include benzophenone, bis (5-benzoyl-4-hydroxy-2-methoxyphenyl) methane, 1,4-bis (4-benzoyl-3-hydroxyphenone) -butane and the like.

  Examples of the silicate compound include pt-butylphenyl silicate.

  Examples of the benzoate compound include 2,4-di-t-butylphenyl-3 ', 5'-di-t-butyl-4'-hydroxybenzoate.

  Examples of triazole compounds include 2,2′-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol], 2- (3 , 5-Di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (2H-benzotriazol-2-yl) -p-cresol, 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol, 2-benzotriazol-2-yl-4,6-di-tert-butylphenol, 2- [5-chloro (2H) -benzotriazole- 2-yl] -4-methyl-6-tert-butylphenol, 2- (2H-benzotriazol-2-yl) -4,6-di-tert-butylphenol, 2- 2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol, 2- (2H-benzotriazol-2-yl) -4-methyl-6- (3,4) , 5,6-tetrahydrophthalimidylmethyl) phenol, methyl 3- (3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate / polyethylene glycol 300 reaction product 2- (2H-benzotriazol-2-yl) -6- (linear and side chain dodecyl) -4-methylphenol, 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2- Hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 3- (2H-benzotriazol-2-yl ) -5- (1,1-dimethylethyl) -4-hydroxy -C7-9 side chain and straight chain alkyl esters. Furthermore, as triazine compounds, 2-mono (hydroxyphenyl) -1,3,5-triazine compounds, 2,4-bis (hydroxyphenyl) -1,3,5-triazine compounds, 2,4,6- And tris (hydroxyphenyl) -1,3,5-triazine compounds, specifically, 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-butoxy) Enyl) -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-triazine, 2,4-diphenyl-6- (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl -6- (2-hydroxy-4-benzyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxyethoxy) -1,3,5-triazine, 2,4-bis (2-hydroxy-4-butoxyphenyl) -6- (2,4-dibutoxyphenyl) -1,3-5-triazine, 2,4,6-tris (2-hydroxy-4- Me Xylphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-ethoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4) -Propoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy) -4-butoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4,6-tris ( 2-hydroxy-4-octyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4 6-Tris (2-hydroxy-4-benzyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-ethoxyethoxyphenyl) -1,3,5-triazine, 2,4 , 6-Tris (2-hydroxy-4-butoxyethoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-propoxyethoxyphenyl) -1,3,5-triazine 2,4,6-tris (2-hydroxy-4-methoxycarbonylpropyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4-ethoxycarbonylethyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-4- (1- (2-ethoxyhexyloxy) -1-oxopropane-2- Ruoxy) phenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-methoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-ethoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-propoxyphenyl) -1,3,5 Triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-butoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4) -Butoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-hexyloxyphenyl) -1,3,5-triazine, 2,4,6- Tris (2-hydroxy 3-methyl-4-octyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-benzyloxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-ethoxy) Ethoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-butoxyethoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-propoxyethoxyphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-methoxycarbonylpropyloxy) Ciphenyl) -1,3,5-triazine, 2,4,6-tris (2-hydroxy-3-methyl-4-ethoxycarbonylethyloxyphenyl) -1,3,5-triazine, 2,4,6- And tris (2-hydroxy-3-methyl-4- (1- (2-ethoxyhexyloxy) -1-oxopropan-2-yloxy) phenyl) -1,3,5-triazine.

  Among them, 2,4-bis (2,4-dimethylphenyl) -6- [2-hydroxy-4 is preferred because it is highly compatible with amorphous thermoplastic resins, particularly acrylic resins, and has excellent absorption characteristics. UV absorbers having-(3-alkyloxy-2-hydroxypropyloxy) -5-α-cumylphenyl] -s-triazine skeleton (alkyloxy; long-chain alkyloxy groups such as octyloxy, nonyloxy, decyloxy, etc.) It is done.

  Further, an ultraviolet absorber having a 2,4,6-tris (hydroxyphenyl) -1,3,5-triazine skeleton is preferably used, and 2,4,6-tris (2-hydroxy-4-long chain alkyloxy) is used. Group-substituted phenyl) -1,3,5-triazine skeleton and 2,4,6-tris (2-hydroxy-3-alkyl-4-long-chain alkyloxy group-substituted phenyl) -1,3,5-triazine skeleton The ultraviolet absorber having is a particularly preferred triazine-based ultraviolet absorber.

  Examples of commercially available products include “Tinuvin 1577”, “Tinuvin 460”, “Tinuvin 477” (manufactured by BASF Japan) as triazine-based UV absorbers, and “Adeka Stub LA-31” (manufactured by ADEKA) as triazole-based UV absorbers. It is done.

  These can be used alone or in combination of two or more. Moreover, it is also preferable to use together the method of copolymerizing the said ultraviolet absorptive monomer with an ultraviolet absorber.

  Although the compounding quantity of a ultraviolet-stable monomer ultraviolet absorber is not specifically limited, It is preferable that it is 0.01-25 mass% in the film containing an acrylic resin, More preferably, it is 0.05-10 mass%. . If the amount added is too small, the contribution to improving weather resistance is low, and if it is too large, the mechanical strength may be lowered or yellowing may be caused.

  The light transmittance at a wavelength of 380 nm of the acrylic resin film containing the ultraviolet absorber is preferably 30% or less, more preferably 20% or less, still more preferably 10% or less, and particularly preferably 5% or less. .

  When the light transmittance at a wavelength of 380 nm exceeds 30%, the deterioration of the polarizer cannot be sufficiently suppressed. More preferably, the light transmittance is 20% or less, more preferably 10% or less, and most preferably 5% or less.

  The optical film of the present invention preferably has a b value of 2.0% or less. More preferably, b value is 1.5% or less, More preferably, it is 1.0% or less, Most preferably, it is 0.5% or less. By setting the b value to 2.0% or less, the color feeling displayed when the present optical film is incorporated into an image display device is excellent.

  The ultraviolet absorber preferably has a molecular weight of 600 or more, more preferably 650 or more, and still more preferably 700 or more.

  When the molecular weight is less than 600, foaming may occur or the ultraviolet absorbent may bleed out when the acrylic resin composition to which the ultraviolet absorbent has been added is molded. In addition, the UV absorber may evaporate due to heat applied at the time of molding, resulting in problems such as reduced UV absorption ability of the resulting resin molded product and contamination of the molding equipment with the evaporated UV absorber. There is.

  On the other hand, the upper limit of the molecular weight of the ultraviolet absorber is preferably 10,000 or less, more preferably 8000 or less, and even more preferably 5000 or less. When the molecular weight exceeds 10,000, compatibility with the acrylic resin is lowered, and optical properties such as hue and turbidity of the finally obtained resin molded product are lowered.

  The acrylic resin film may contain other additives. Other additives include, for example, hindered phenol-based, phosphorus-based and sulfur-based antioxidants; light-resistant stabilizers, weather-resistant stabilizers, heat-stabilizers and other stabilizers; glass fibers, carbon fibers and other reinforcing materials; Near-infrared absorbers; flame retardants such as tris (dibromopropyl) phosphate, triallyl phosphate, antimony oxide; antistatic agents composed of anionic, cationic, and nonionic surfactants; inorganic pigments, organic pigments, dyes Coloring agents such as: organic fillers, inorganic fillers; anti-blocking agents; resin modifiers; organic fillers, inorganic fillers; plasticizers; lubricants;

  The content of other additives in the acrylic resin film is preferably 0 to 5% by mass, more preferably 0 to 2% by mass, and still more preferably 0 to 1% by mass.

  The glass transition temperature (Tg) of the acrylic resin film is preferably 100 ° C. or higher, more preferably 110 ° C. or higher, still more preferably 115 ° C. or higher, and particularly preferably 120 ° C. or higher. Although the upper limit of Tg of an acrylic resin film is not specifically limited, From a viewpoint of the drawability of the said film, Preferably it is 170 degrees C or less.

  The (meth) acrylic polymer having a ring structure in the main chain increases the Tg of an acrylic resin film and an optical film composed of the film, and improves heat resistance.

  The thickness of an acrylic resin film is not specifically limited, Preferably it is 5-200 micrometers, More preferably, it is 10-100 micrometers.

  If the thickness is less than 5 μm, sufficient strength as an optical film may not be maintained. If the thickness exceeds 200 μm, the transparency of the film may be reduced, making it unsuitable for use as an optical film.

  In addition to this, the thickness of the excessively large acrylic resin film allows the adhesive composition used for the adhesive layer to be dried when the optical film of the present invention is bonded to another member (for example, a functional film). Inhibit. In particular, when using a water-based adhesive composition, the quality and production of an optical member having a laminated structure of the optical film of the present invention and other members is slowed by drying of water as a solvent or dispersion medium. It tends to cause a decline in sex.

  The wetting tension on the surface of the acrylic resin film is preferably 40 mN / m or more, more preferably 50 mN / m or more, and further preferably 55 mN / m or more. When the surface wetting tension is 40 mN / m or more, the adhesion between the optical film of the present invention and other members is further improved.

  In order to adjust the surface wetting tension, any appropriate surface treatment may be applied to the surface of the acrylic resin film. The surface treatment is, for example, corona discharge treatment, plasma treatment, ozone spraying, ultraviolet irradiation, flame treatment, or chemical treatment. Of these, corona discharge treatment and plasma treatment are preferred.

  The acrylic resin film may be an unstretched film or a stretched film. The stretched film may be a uniaxially stretched film or a biaxially stretched film. The biaxially stretched film may be a simultaneous biaxially stretched film or a sequential biaxially stretched film. The direction of the slow axis of the stretched film may be the film flow direction, the width direction, or an arbitrary direction.

  When the acrylic resin film is a biaxially stretched film, the mechanical strength of the optical film of the present invention is improved. Depending on the composition of the acrylic resin, the development of retardation due to stretching can be suppressed, and an optically isotropic optical film can be obtained. When the optical film of the present invention is a retardation film, the acrylic resin film is a stretched film.

  The acrylic resin film can be formed by a known film deposition method. Examples of the film forming method include a solution casting method (solution casting method), a melt extrusion method, a calendar method, and a compression molding method. Of these, the solution casting method and the melt extrusion method are preferable.

  The acrylic resin used for film formation can be formed by a known method. For example, an acrylic resin is formed by sufficiently mixing (meth) acrylic polymer, other thermoplastic polymer and additives blended according to the composition of the acrylic resin to be obtained by an appropriate mixing method. .

  The mixing method is, for example, extrusion kneading or mixing in a solution state. A commercially available acrylic resin may be used for film formation. Commercially available acrylic resins are, for example, Acrypet VH and Acrypet VRL20A (both manufactured by Mitsubishi Rayon). Any suitable mixer such as an omni mixer, a single screw extruder, a twin screw extruder, or a pressure kneader can be used for the extrusion kneading.

  An apparatus for performing the solution casting method is, for example, a drum type casting machine, a band type casting machine, or a spin coater.

  The solvent used for the solution casting method is not limited as long as the acrylic resin is dissolved. Examples of the solvent include aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as cyclohexane and decalin; esters such as ethyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. Methanol, ethanol, isopropanol, butanol, isobutanol, alcohols such as methyl cellosolve, ethyl cellosolve, butyl cellosolve; ethers such as tetrahydrofuran and dioxane; halogenated hydrocarbons such as dichloromethane, chloroform and carbon tetrachloride; dimethylformamide; dimethyl sulfoxide is there. Two or more of these solvents may be used in combination.

  Examples of the melt extrusion method include a T-die method and an inflation method. The molding temperature during melt extrusion is preferably 150 to 350 ° C, more preferably 200 to 300 ° C. When the T-die method is selected, for example, a belt-like acrylic resin film can be formed by attaching a T-die to the tip of a known extruder. The formed strip-shaped acrylic resin film may be wound on a roll to form a film roll. In the melt extrusion method, from the formation of an acrylic resin by mixing materials to the formation of an acrylic resin film using the resin can be continuously performed. A band-shaped optical film may be obtained by forming an easy-adhesion layer on the band-shaped acrylic resin film.

  The acrylic resin film which is a stretched film can be formed by stretching the acrylic resin film obtained as described above. The stretching method is not particularly limited, and a known stretching machine can be used for stretching. When the acrylic resin film is formed by the T-die method, the temperature of the roll for winding the formed film can be adjusted to simultaneously perform uniaxial stretching and film winding.

  When the acrylic resin film is formed by melt extrusion, steps from the formation of the acrylic resin by mixing the materials to the formation of the optical film as the stretched film through the formation of the acrylic resin film can be performed continuously.

  After stretching, heat treatment (annealing) of the film may be performed in order to stabilize the optical isotropy and mechanical properties of the film. The heat treatment method and conditions can be selected as appropriate.

(1-2. Easy adhesion layer)
The optical film of the present invention has an easy-adhesion layer (a) containing a polyester-acrylic composite resin (B).

  Although the thickness of an easily bonding layer (a) is not specifically limited, Although it changes with thickness of an acrylic resin film, 1 nm-10 micrometers are preferable, 10 nm-5 micrometers are more preferable, and 50 nm-1.5 micrometers are more preferable. In this range, the effect of improving the adhesion between the optical film and the functional coating layer by the easy adhesion layer (a) is good. In addition to this, it is possible to suppress the development of a phase difference in the easy-adhesion layer itself.

  The easy-adhesion layer (a) may contain fine particles as long as the adhesion is not impaired. Any appropriate fine particles can be used as the fine particles, and water-dispersible fine particles are preferable. Specifically, either inorganic fine particles or organic fine particles can be used, and organic-inorganic composite fine particles may 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 plate 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. Furthermore, silica is excellent also in adhesiveness with an acrylic resin film.

  The particle diameter (average primary particle diameter) of the fine particles is 300 nm or less, preferably 10 to 300 nm, more preferably 20 to 200 nm, and still more preferably 30 to 150 nm.

  By using fine particles of such a particle size, irregularities are appropriately formed on the surface of the easy-adhesion layer, and the frictional force at the contact surface between the acrylic resin film and the easy-adhesion layer and / or the easy-adhesion layer is effectively reduced. Can do. 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 plate can be suppressed more.

  The particle size distribution of the fine particles is preferably 1.0 to 1.4, and more preferably 1.0 to 1.2.

  The average primary particle size and particle size distribution of the fine particles can be determined by a laser diffraction / scattering particle size distribution measuring device (for example, Submicron Particle Sizer NICOM 380 manufactured by Particle Sizing Systems).

  Specifically, the equivalent spherical distribution of the fine particles dispersed in the medium is obtained by the measuring device. Next, in the obtained distribution, the particle diameter of particles with an integrated volume fraction of 50% accumulated from the large particle side is obtained, and this is used as the average primary particle diameter (d50) of the fine particles.

  Separately from this, the particle diameter (d25) of particles with an integrated volume fraction of 25% and the particle diameter (d75) of 75% of particles accumulated from the large particle side in the distribution are obtained, and the ratio (d25 / d75) Is the particle size distribution of the fine particles. In addition, although a medium can be suitably selected according to the structure and capability of a particle size distribution apparatus, for example, it is water, it is not restricted to a liquid.

  When the composition forming the easy-adhesion layer (a) is aqueous, the fine particles are preferably blended 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. Examples of commercially available products include the Quartron PL series manufactured by Fuso Chemical Industry Co., Ltd., the Snowtex series manufactured by Nissan Chemical Industry Co., Ltd., the Aerodisp series manufactured by Nippon Aerosil Co., Ltd., and the AEROSIL series.

  The upper limit of the content of fine particles in the easy-adhesion layer (a) is preferably less than 10% by mass, more preferably less than 5% by mass, and even more preferably less than 2% by mass. If the content of the fine particles exceeds 10% by mass, the coating strength of the easy-adhesion layer may be reduced or the transparency may be impaired. The lower limit of the content of fine particles in the easy adhesion layer is preferably 0.1% by mass or more, more preferably 0.15% by mass or more, and further preferably 0.2% by mass or more. When the content of the fine particles is less than 0.1% by mass, the blocking resistance of the optical film may be lowered.

  The polyester-acrylic composite resin (B) forming the easy adhesion layer (a) may be formed from a mixture of a polyester resin and an acrylic resin, or a resin obtained by copolymerizing a (meth) acrylic monomer with a polyester resin. May be formed. From the viewpoint of environmental regulations, the polyester-acrylic composite resin (B) is preferably water-dispersible, especially the polyester resin is water-dispersible, since an aqueous system is more advantageous than a solvent system when forming an easily adhesive layer. It is more preferable that

  The dicarboxylic acid component, which is a copolymer component of the polyester resin that forms the polyester-acrylic composite resin (B), contains an ester-forming alkali metal salt compound as an essential component and is contained in addition to the ester-forming alkali metal salt compound. Possible dicarboxylic acid components include fragrances such as phthalic acid, terephthalic acid, dimethyl terephthalate, isophthalic acid, dimethyl isophthalate, 2,5-dimethylterephthalic acid, 2,6-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, orthophthalic acid, etc. Aliphatic dicarboxylic acids, succinic acid, adipic acid, azelaic acid, sebacic acid, aliphatic dicarboxylic acids such as dodecane dicarboxylic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid.

  As the dicarboxylic acid component other than the ester-forming sulfonic acid alkali metal salt compound, an aromatic dicarboxylic acid is preferable, and since the aromatic nucleus of the aromatic dicarboxylic acid has a high affinity with a hydrophobic plastic, adhesion is improved, There is an advantage that it is excellent in degradability. In particular, terephthalic acid and isophthalic acid are preferable.

  It is preferable that the ester-forming sulfonic acid alkali metal salt compound is contained in the total acid component (in the dicarboxylic acid component) in an amount of 6 to 20 mol%. More preferably, it is 10-18 mol%. When the content of the ester-forming alkali metal sulfonate compound is less than 6 mol%, the dispersion time of the resin in water becomes long and the solvent resistance is not sufficient. Conversely, if it exceeds 20 mol%, the water resistance tends to decrease.

  It is preferable that 80-94 mol% of dicarboxylic acid components other than the ester-forming sulfonic acid alkali metal salt compound are contained in the total acid component.

  Examples of the ester-forming sulfonic acid alkali metal salt compound include alkali metal salts such as sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfoisophthalic acid, 4-sulfonaphthalenic acid-2,7-dicarboxylic acid (alkali sulfonic acid alkali). Metal salts) and their ester-forming derivatives, and the sodium salt of 5-sulfoisophthalic acid and its ester-forming derivatives are more preferably used.

  Examples of the diglycol component that is a copolymer component of the polyester resin include diethylene glycol and an aliphatic group having 2 to 8 carbon atoms or an alicyclic glycol group having 6 to 12 carbon atoms. Specific examples of the aliphatic having 2 to 8 carbon atoms or the alicyclic glycol having 6 to 12 carbon atoms include ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, Neopentyl glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, 1,6-hexanediol , P-xylylene glycol, triethylene glycol and the like, and one or more of these may be used in combination.

  It is preferable that the usage-amount of the said dicarboxylic acid component and the usage-amount of a diglycol component are 2: 1 to 1: 3 by molar ratio.

  It is preferable to contain 20-80 mol% of diethylene glycol in the total glycol component. Even if diethylene glycol is outside this range, solvent resistance to alcohol can be obtained, but solvent resistance may be insufficient with respect to aromatic solvents such as toluene and xylene.

  The polyester resin needs to have a number average molecular weight of 2,000 to 30,000, and a preferred number average molecular weight is 2,500 to 25,000. If the number average molecular weight is less than 2,000, the resin physical properties such as water resistance and solvent resistance may be deteriorated, and if it exceeds 30,000, only water-dispersible and difficult to handle resins can be obtained. There is.

  The polyester resin is produced by a known production technique by subjecting dicarboxylic acid and diglycol to esterification or transesterification and then polycondensation reaction, but the production method is not limited at all. That is, the above-mentioned acid component and glycol component are esterified or transesterified at 130 to 200 ° C., and then subjected to a polycondensation reaction at 200 to 250 ° C. under reduced pressure conditions to obtain a target polyester resin. it can.

  Examples of the reaction catalyst used at this time include metal acetates such as zinc acetate and manganese acetate, metal oxides such as antimony oxide and germanium oxide, and titanium compounds.

  When the polyester resin is water-dispersible, it is used by uniformly dispersing water in water or water containing an aqueous solvent under heating and stirring at 50 to 90 ° C. Since the aqueous dispersion obtained in this way is difficult to obtain a uniform dispersion when the solid content concentration becomes high, the polyester solid content concentration is preferably 30% by mass or less.

  Specific examples of the aqueous solvent include lower alcohols such as methanol, ethanol, normal propanol, and isopropanol, polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, and glycerin, ethylene glycol monomethyl ether, and ethylene glycol monoethyl. Examples include ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol acetate, diethylene glycol monomethyl ether, dipropylene glycol monomethyl ether and the like.

  The acrylic resin to be compounded with the polyester resin preferably has an epoxy group. When the polyester-acrylic composite resin (B) has an epoxy group, the solvent resistance of the easy-adhesion layer (a) and the adhesion with the functional coating layer are improved.

  Epoxy group-containing acrylic resin is a resin obtained by copolymerizing a homopolymer of an epoxy group-containing radical polymerizable unsaturated monomer or an epoxy group-containing radical polymerizable unsaturated monomer and another radical polymerizable unsaturated monomer copolymerizable therewith. It is.

  It is preferable that 10-100 mass% of epoxy group containing radically polymerizable unsaturated monomers are contained in all the monomers, More preferably, it is 20-100 mass%.

  The epoxy group-containing radically polymerizable unsaturated monomer is considered to improve water resistance and solvent resistance by promoting internal crosslinking of the epoxy group-containing acrylic resin. In particular, the solvent resistance to ketone solvents such as acetone and methyl ethyl ketone and ester solvents such as ethyl acetate and butyl acetate is remarkable.

  Solvent resistance to alcohol can be obtained even if the content of the epoxy group-containing radically polymerizable unsaturated monomer is less than 10% by mass, but it is resistant to ketone solvents such as acetone and methyl ethyl ketone, and ester solvents such as ethyl acetate and butyl acetate. Insufficient sex.

  Examples of the radical polymerizable unsaturated monomer containing an epoxy group include glycidyl ethers such as glycidyl acrylate, glycidyl methacrylate, and allyl glycidyl ether.

  Examples of the radical polymerizable unsaturated monomer that can be copolymerized with the epoxy group-containing radical polymerizable unsaturated monomer include vinyl esters, unsaturated carboxylic acid esters, unsaturated carboxylic acid amides, unsaturated nitriles, unsaturated carboxylic acids, allyl compounds, and the like. Examples thereof include nitrogen-based vinyl monomers, hydrocarbon vinyl monomers, and vinyl silane compounds.

  Examples of vinyl esters include vinyl propionate, vinyl stearate, higher tertiary vinyl esters, vinyl chloride, and vinyl bromide.

  Examples of unsaturated carboxylic acid esters include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, butyl maleate, octyl maleate, butyl fumarate, Octyl fumarate, hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, ethylene glycol dimethacrylate, ethylene glycol diacrylate, Examples thereof include polyethylene glycol dimethacrylate and polyethylene glycol diacrylate.

  Examples of unsaturated carboxylic acid amides include acrylamide, methacrylamide, methylol acrylamide, and butoxymethylol acrylamide. An example of the unsaturated nitrile is acrylonitrile.

  Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, maleic acid acidic ester, fumaric acid acidic ester, and itaconic acid acidic ester.

  Examples of the allyl compound include allyl acetate, allyl methacrylate, allyl acrylate, and diallyl itaconate.

  Examples of the nitrogen-containing vinyl monomer include vinyl pyridine and vinyl imidazole, and examples of the hydrocarbon vinyl monomer include ethylene, propylene, hexene, octene, styrene, vinyl toluene, and butadiene.

  Examples of the vinylsilane compound include dimethylvinylmethoxysilane, dimethylvinylethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropyldimethoxysilane.

  The polyester-acrylic composite resin (B) preferably further has a carboxyl group. When an unsaturated carboxylic acid such as acrylic acid or methacrylic acid is used as the radical polymerizable unsaturated monomer, the effect of improving the solvent resistance and the adhesion to the functional coating layer is further exhibited by crosslinking with the epoxy group.

  It is preferable that 5-20 mass% of unsaturated carboxylic acid monomers are contained in all the monomers. When the content of the unsaturated carboxylic acid monomer is less than 5% by mass, the combined effect is not observed. When the content exceeds 20% by mass, the viscosity during polymerization becomes too high, or the liquid gels with time, resulting in storage stability. It gets worse.

  The epoxy group-containing acrylic resin is produced by a known production technique, but the production method is not limited at all. Here, the manufacturing method by emulsion polymerization is described.

  For example, ion-exchanged water, a polymerization initiator, and a surfactant are charged into a reaction tank, and then ion-exchanged water and a surfactant are charged into a dropping tank, and monomers are added to prepare an emulsion. Perform the reaction. The reaction temperature is 60 to 100 ° C., and the reaction is performed for 4 to 10 hours.

  As the surfactant used for the emulsion polymerization, a general anionic or nonionic reactive surfactant and a non-reactive surfactant may be used alone or in combination of two or more.

  Specific examples of reactive surfactants include anionic surfactants such as alkylallylsulfosuccinate, polyoxyethylene alkylpropenyl phenyl ether sulfate, polyoxyalkylene alkenyl ether sulfate, and (meth) acrylate sulfate. And nonionic surfactants such as polyoxyethylene alkylpropenyl phenyl ether, polyoxyalkylene alkenyl ether, (meth) acrylate sulfate, and the like.

  Specific examples of non-reactive surfactants include anionic systems such as alkyl sulfates, alkylbenzene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ether disulfonates, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl phosphate esters, etc. Nonionic surfactants such as surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene diphenyl ethers, polyoxyethylene fatty acid esters and the like can be mentioned.

  As a polymerization initiator used for emulsion polymerization, a general radical polymerizable initiator, for example, a water-soluble peroxide such as potassium persulfate, ammonium persulfate, hydrogen peroxide, benzoyl peroxide, t-butyl hydroperoxide, or the like Or an azo compound such as azobisisobutyronitrile.

  The polyester-acrylic composite resin (B) of the present invention preferably has a resin solid content weight ratio of the polyester resin component and the acrylic resin component of 10 to 80/90 to 20, more preferably 20 to 70/80. ~ 30.

  When the polyester resin is less than 10% by mass, that is, when the acrylic resin exceeds 90% by mass, the adhesion to the substrate and the transparency of the film are lowered, and the polyester resin exceeds 80% by mass, that is, the acrylic resin is less than 20% by mass. If so, sufficient solvent resistance and water resistance cannot be obtained.

  The said easily bonding layer (a) should just be formed in one main surface of the said acrylic resin film. In this specification, the “main surface” is not a surface in the thickness direction of the film, but a surface determined by the side in the longitudinal direction and the side in the width direction of the film, that is, the surface and the back surface. That means.

  The formation method of the easily bonding layer with respect to the main surface of an acrylic resin film is not limited, What is necessary is just to follow a well-known method. The easy adhesion layer is formed by applying an easy adhesion composition containing the polyester-acrylic composite resin (B) to the main surface of the acrylic resin film to form a coating film of the composition, and then drying the formed coating film. It is preferable to form them. The easy-adhesion composition may contain the fine particles described above.

  The easy-adhesion composition is preferably an aqueous composition. The water-based composition has a smaller work load on the environment when forming the easy-adhesion layer than the organic solvent-based composition, and is excellent in workability. The aqueous composition is, for example, a resin dispersion having easy adhesion. The dispersion is typically an emulsion of resin having easy adhesion. The polyester-acrylic composite resin emulsion becomes a layer containing the polyester-acrylic composite resin (B) by drying. The fine particles contained in the emulsion remain in the resin layer as they are.

  When the easy-adhesion composition containing the polyester-acrylic composite resin (B) is aqueous, it is preferable to use an organic solvent that is compatible with water. 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 It is.

  The easy-adhesion composition may contain an additive in addition to the resin and fine particles having easy adhesion. Additives are, for example, dispersion stabilizers, thixotropic agents, antioxidants, ultraviolet absorbers, antifoaming agents, thickeners, dispersants, surfactants, catalysts, and antistatic agents.

  In the water-based easy-adhesion composition used for forming the easy-adhesion layer (a) which is a polyester-acrylic composite resin layer, the content of the polyester-acrylic composite resin (B) in the composition is 1 to 20% by mass. Preferably, 2 to 15% by mass is more preferable. When the content is in these ranges, the coating property when applying the easy-adhesion composition to the surface of the acrylic resin film is high, and the effect of the easy-adhesion layer can be sufficiently secured.

  When this composition further contains a crosslinking agent, the content of the crosslinking agent is preferably 1 to 30 parts by weight and more preferably 3 to 20 parts by weight with respect to 100 parts by weight of the polyester-acrylic composite resin (B). The content of fine particles in the easy-adhesion composition containing the polyester-acrylic composite resin is preferably 0.3 to 10 parts by weight, and 0.5 to 1 part by weight with respect to 100 parts by weight of the polyester-acrylic composite resin (B). Part is more preferred.

  As for the optical film of this invention, the easily bonding layer (b) may be formed in the main surface on the opposite side to the main surface in which the easily bonding layer (a) is formed of an acrylic resin film. The resin constituting the easy-adhesion layer (b) is not particularly limited as long as it is a known resin having an easy-adhesion property. For example, urethane resin, cellulose resin, polyol resin, polycarboxylic acid resin, polyester resin, acrylic resin It is.

  The number average molecular weight of the resin constituting the easy adhesion layer (b) is preferably from 50,000 to 600,000, more preferably from 10,000 to 400,000.

  Like the easy-adhesion layer (a), the easy-adhesion layer (b) may contain fine particles, and preferable fine particles include the fine particles described above.

  The resin constituting the easy-adhesion layer (b) is preferably a urethane resin. In this case, the adhesiveness with respect to a polarizer improves rather than when an easily bonding layer is another resin layer.

  The urethane resin is not particularly limited, and is typically a resin obtained by reacting a polyol and a polyisocyanate. Any polyol having two or more hydroxyl groups in the molecule can be adopted as the polyol. The polyol is, for example, a polyacryl polyol, a polyester polyol, or a polyether polyol. Two or more polyols may be combined.

  The polyacryl polyol is typically a copolymer of a (meth) acrylic acid ester monomer and a monomer having a hydroxyl group.

  The (meth) acrylic acid ester monomer is, for example, methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, or cyclohexyl (meth) acrylate.

  Examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, (Meth) acrylic acid hydroxyalkyl esters such as (meth) acrylic acid 4-hydroxybutyl and (meth) acrylic acid 2-hydroxypentyl; (meth) acrylic acid monoesters of polyhydric alcohols such as glycerin and trimethylolpropane; N -Methylol (meth) acrylamide.

  The polyacryl polyol may be a copolymer with further other monomers. Other monomers are not limited as long as they can be copolymerized with the (meth) acrylic acid ester monomer and the monomer having a hydroxyl group.

  Such other monomers include, for example, 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 Unsaturated amides such as (meth) 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; Halogenated α, β-unsaturated aliphatic monomers such as vinyl chloride and vinylidene chloride; α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene.

  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, and tetrahydrophthalic acid. 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. Alicyclic dicarboxylic acid ; Or, acid anhydrides thereof, a reactive derivative such as an alkyl ester, acid halide.

  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 Coal, 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, 1,4-cyclohexanediol, bisphenol A, bisphenol F, hydrogenated bisphenol A, and hydrogenated bisphenol F.

  The polyether polyol is typically obtained by adding an alkylene oxide to a polyhydric alcohol by ring-opening polymerization. The polyhydric alcohol is, for example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, or trimethylolpropane. The alkylene oxide is, for example, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, tetrahydrofuran.

  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, lysine diisocyanate, Aliphatic diisocyanates such as 2-methylpentane-1,5-diisocyanate and 3-methylpentane-1,5-diisocyanate; isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4'-cyclohexylmethane diisocyanate, 1,4-cyclohexane Alicyclic diisodies such as diisocyanate, methylcyclohexylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane Anate; 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 An aromatic aliphatic diisocyanate such as range isocyanate.

  The urethane resin preferably has a carboxyl group. By having a carboxyl group, the performance (easy adhesion) of the easy adhesion layer is improved. This effect is particularly remarkable in a high temperature and high humidity environment.

  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 a polyol and a polyisocyanate. Examples of the chain extender having a free carboxyl group are dihydroxycarboxylic acid and dihydroxysuccinic acid. The dihydroxycarboxylic acid is a dialkylol alkanoic acid such as dimethylol alkanoic acid (for example, dimethylol acetic acid, dimethylol butanoic acid, dimethylol propionic acid, dimethylol butyric acid, dimethylol pentanoic acid).

  The acid value of the urethane resin is preferably 10 or more, more preferably 10 to 50, and particularly preferably 20 to 45. In these cases, the performance of the easy-adhesion layer (for example, adhesion with other functional films such as a polarizer) is further improved.

  The urethane resin may be obtained by reaction with other polyols or other chain extenders in addition to the components described above.

  Other polyols include, for example, sorbitol, 1,2,3,6-hexanetetraol, 1,4-sorbitan, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, trimethylolethane , Trimethylolpropane, pentaerythritol, and other polyols having three or more hydroxyl groups.

  Other chain extenders include, for example, 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; Fats such as isophorone diamine and 4,4'-dicyclohexylmethanediamine Cyclic diamines; aromatic diamines such as xylylenediamine and tolylenediamine.

  The urethane resin can be formed by applying a known method. This method is, for example, a one-shot method in which each component is reacted at once, or a multi-stage method in which the components are reacted stepwise. The urethane resin having a carboxyl group is preferably formed by a multistage method since the introduction of the carboxyl group is easy. The catalyst used for forming the urethane resin is not particularly limited.

  The water-based easy-adhesion composition used for forming the easy-adhesion layer (b) that is a urethane resin layer preferably contains a neutralizing agent in addition to the fine particles and the urethane resin. In this case, the stability of the urethane resin in the easy-adhesion composition is improved. Examples of the neutralizing agent include ammonia, N-methylmorpholine, triethylamine, dimethylethanolamine, methyldiethanolamine, triethanolamine, morpholine, tripropylamine, ethanolamine, triisopropanolamine, 2-amino-2-methyl-1- Propanol.

  When the easy-adhesion composition containing a urethane resin is aqueous, it is preferable to use an organic solvent that is inactive with respect to the polyisocyanate and is compatible with water when the urethane resin is formed. Examples of organic solvents 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. is there.

  The easy-adhesion composition containing a urethane resin preferably contains a crosslinking agent, and in this case, the performance of the easy-adhesion layer is improved. The crosslinking agent is not particularly limited. When the urethane resin has a carboxyl group, the crosslinking agent is preferably a polymer having a group capable of reacting with the carboxyl group.

  Examples of the group capable of reacting with a carboxyl group are an organic amino group, an oxazoline group, an epoxy group, and a carbodiimide group, and an oxazoline group is preferable. The crosslinking agent having an oxazoline group has a long pot life at room temperature when mixed with a urethane resin, and has a good workability because the crosslinking reaction proceeds by heating. The polymer is, for example, a (meth) acrylic polymer or a styrene / acrylic polymer, and a (meth) acrylic polymer is preferable. When the crosslinking agent is a (meth) acrylic polymer, the performance of the easy adhesion layer is further improved. In addition to this, the (meth) acrylic polymer is stably compatible with the water-based easy-adhesive composition and crosslinks the urethane resin well.

  In the easily bonding composition containing a urethane resin, the content of the urethane resin in the composition is preferably 1.5 to 15% by mass, and more preferably 2 to 10% by mass. When content rate exists in these ranges, the applicability | paintability at the time of apply | coating an easily bonding composition to the surface of an acrylic resin film is high. When this composition further contains a crosslinking agent, the content of the crosslinking agent is preferably 1 to 30 parts by weight and more preferably 3 to 20 parts by weight with respect to 100 parts by weight of the urethane resin (solid content). The content of fine particles in the easy-adhesion composition containing a urethane resin is preferably 0.3 to 10 parts by weight, and more preferably 0.5 to 1 part by weight with respect to 100 parts by weight of the urethane resin (solid content).

(1-3. Optical film)
The optical film of the present invention is an optical film having an acrylic resin film made of an acrylic resin (A) and an easy adhesion layer (a) containing a polyester-acrylic composite resin (B).

  An example of the optical film of the present invention is shown in FIG. The optical film 1a shown in FIG. 1 has a structure in which an easy-adhesion layer (a) 3 is formed on one surface of an acrylic resin film 2. Specific configurations of the acrylic resin film 2 and the easy-adhesion layer (a) 3 are as described above.

  The optical film of the present invention is a film having an easy-adhesion layer (a) that has both blocking resistance and transparency. Regarding transparency, the optical film of the present invention usually has a haze of 1.0% or less. Depending on the configuration of the optical film of the present invention, the haze is 0.5% or less, and further 0.3% or less. The haze is measured based on the specification of JIS K7136.

  When the optical film of the present invention has the easy-adhesion layer (a), in addition to improving the adhesion to the functional coating layer, the folding strength of the film may be improved. In general, it is known that the acrylic resin film is stretched to improve the folding strength of the film, but after forming the easy-adhesive layer (a) having excellent adhesion to the acrylic resin film, the acrylic resin film The bending strength can be further improved by stretching.

  The optical film of the present invention is, for example, a polarizer protective film, a retardation film, a viewing angle compensation film, a light diffusion film, a reflective film, an antireflection film, an antiglare film, a brightness enhancement film, and a conductive film for a touch panel.

  The retardation exhibited by the optical film of the present invention can be controlled by the composition and stretched state of the acrylic resin film. The optical film of the present invention may be an optically isotropic film or a film having optical anisotropy (for example, expressing birefringence such as retardation).

  The optical film of the present invention may be wound around a roll (may be a film roll). Since the optical film of the present invention is excellent in blocking resistance, it is suitable for a film roll.

  FIG. 2 shows an embodiment of an optical film according to the present invention, in which a functional coating layer is formed on the surface of the easy-adhesion layer (a) facing the surface on the acrylic resin film side. An optical film is shown. That is, the optical film of the present invention may be an optical film 1b in which various functional coating layers 4 are formed on the easy adhesion layer (a) 3 as shown in FIG.

  Functional coating layers include, for example, antistatic layers, hard coat layers, antiglare (non-glare) layers, antireflection layers such as low reflection layers and moth-eye layers, ultraviolet shielding layers, heat ray shielding layers, electromagnetic wave shielding layers, and gas barrier layers. And an antifouling layer such as a photocatalyst layer, an adhesive layer, and the like, and can be suitably used for the outermost surface of various image display devices.

  In addition, "the surface facing the said acrylic resin film side surface of the said easily bonding layer (a)" is the surface which has contact | adhered with the said acrylic resin film among the surfaces which an easily bonding layer (a) has. The opposite side.

  FIG. 3 shows an embodiment of the optical film according to the present invention, and an adhesive layer is formed on the surface of the easy-adhesion layer (b) facing the surface on the acrylic resin film side. The optical film has shown the optical member joined to the other member through the adhesive layer. In FIG. 3, 1c is an optical film, 5 is an easily adhesive layer (b), 6 is an adhesive layer, and 7 is another member.

  The “surface of the easy adhesion layer (b) facing the surface on the acrylic resin film side” is the surface of the easy adhesion layer (b) that is in close contact with the acrylic resin film. The opposite side.

  As shown in FIG. 3, the optical film of the present invention can be bonded to another member 7 such as a functional film to become an optical member. At this time, the surface of the optical film 1c of the present invention on the side of the easy adhesion layer (b) 5 (the surface opposite to the surface on which the easy adhesion layer (a) is formed) is the easy adhesion layer (b) 5 and It is preferable to be joined to another member through the adhesive layer 6.

  As shown in FIG. 3, the optical film of the present invention may be a polarizing plate adhered to a polarizer 7 through an easy adhesion layer (b) and an adhesive layer 6. That is, the other member 7 may be a polarizer.

  FIG. 4 shows one embodiment of a polarizing plate according to the present invention, and shows a polarizing plate in which an optical film according to the present invention is bonded to a polarizer. In FIG. 4, 1c and 1d are optical films, 5 is an easily adhesive layer (b), 6 and 9 are adhesive layers, and 8 is a polarizer. Each of the optical films 1c and 1d includes an easy-adhesion layer (b) 5, and an adhesive layer 6 is formed on the surface of each easy-adhesion layer (b) 5 that faces the surface on the acrylic resin film 2 side. The adhesive layer 6 is bonded to the surface of the polarizer 8.

  The optical film of the present invention is suitable for use in an image display device. The image display device is, for example, an electroluminescence (EL) display panel, a plasma display panel (PDP), a field emission display (FED), or an LCD. The LCD has a liquid crystal cell and a polarizing plate disposed on at least one main surface of the liquid crystal cell.

[2. Polarizer〕
The polarizing plate of the present invention will be described. The polarizing plate of the present invention includes the optical film according to the present invention. A pair of polarizing plates is arranged in the LCD so as to sandwich the liquid crystal cell based on the principle of image display. The polarizing plate of the present invention has, for example, a structure in which the optical film (polarizer protective film) of the present invention is laminated on at least one surface of a polarizer via an easy adhesion layer.

  Conventionally, a triacetyl cellulose (TAC) film has been used as the polarizer protective film. However, the TAC film does not have sufficient moisture and heat resistance, and when the TAC film is used as a polarizer protective film, the characteristics of the polarizing plate may be deteriorated under a high temperature or high humidity environment. Further, the TAC film has a retardation in the thickness direction, and this retardation adversely affects the viewing angle characteristics of an image display device such as an LCD, particularly a large screen image display device.

  On the other hand, since the optical film of the present invention, which is a polarizer protective film, is composed of an acrylic resin film, it can improve heat and moisture resistance and optical characteristics as compared to a TAC film.

  The polarizing plate is typically produced by laminating an optical film and a polarizer via an adhesive layer (adhesive layer). When the optical film of this invention has an easily bonding layer (b), both are laminated | stacked so that an easily bonding layer (b) may become a polarizer side.

  Specifically, for example, an adhesive composition that becomes an adhesive layer (adhesive layer) after drying is applied to one surface selected from a polarizer or an optical film, and then the two are bonded together and dried. Let

  Examples of the method for applying the adhesive composition include a roll method, a spray method, and a dipping method. When the adhesive composition contains a metal compound colloid, the adhesive composition is applied so that the thickness of the adhesive layer after drying is larger than the average particle diameter of the metal compound colloid particles. 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.

  The polarizer is not limited, and any appropriate polarizer can be adopted depending on the function required for the polarizing plate. For example, a polarizer is made of a hydrophilic polymer film such as a polyvinyl alcohol (PVA) film, a partially formalized PVA film, or a partially saponified film of an ethylene-vinyl acetate copolymer (EVA). A film uniaxially stretched by adsorbing a dichroic substance such as a reactive dye; a polyene-based oriented film using a dehydrated PVA product or a dehydrochlorinated polyvinyl chloride product. Especially, the film which made the PVA-type film adsorb | suck a dichroic substance and was uniaxially stretched is preferable as a polarizer. This polarizer exhibits a high polarization dichroic ratio. The thickness of the polarizer is not limited and is generally about 1 to 80 μm.

  For example, a polarizer uniaxially stretched by adsorbing iodine to the PVA film is prepared by immersing the PVA film in an aqueous solution containing iodine and uniaxially stretching the film at a stretching ratio of 3 to 7 times. Can do.

  The aqueous solution used for dyeing may contain boric acid, zinc sulfate, zinc chloride and the like as necessary. As an aqueous solution containing iodine, an aqueous solution of iodide such as potassium iodide may be used.

  The PVA film may be immersed in water and washed before dyeing. By washing the PVA-based film with water, dirt, an antiblocking agent and the like present on the surface of the film can be removed. Furthermore, since the PVA film swells by washing with water, unevenness during dyeing is suppressed. Stretching may be performed before dyeing, after dyeing, or simultaneously with dyeing.

  The adhesive composition that becomes an adhesive layer (adhesive layer) after drying is not limited. The adhesive composition preferably contains a PVA-based resin.

  The PVA resin includes, for example, the following polymers: saponified products of polyvinyl acetate and derivatives thereof; saponified products of copolymers of vinyl acetate and other monomers; acetalization, urethanization, ether of PVA Modified, grafted or phosphate ester modified PVA.

  Examples of the other 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; Meta) allylsulfonic acid (soda), sulfonic acid soda (monoalkylmalate), disulfonic acid soda alkylmalate, N-methylolacrylamide, acrylamide alkylsulfonic acid alkali salt, N-vinylpyrrolidone, N-vinylpyrrolidone derivative. . The PVA resin preferably contains acetoacetyl group-containing PVA. In this case, the adhesion between the polarizer and the optical film (acrylic resin film) is improved, and the durability of the polarizing plate is improved.

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

  The acetoacetyl group-containing PVA can be obtained, for example, by reacting PVA and diketene by an arbitrary method. A specific example is a method of adding diketene to a dispersion in which PVA is dispersed in a solvent such as acetic acid; a method of adding diketene to a solution in which PVA is dissolved in a solvent such as dimethylformamide or dioxane; and diketene gas to PVA. Or it is the method of making liquid diketene contact directly.

  The degree of acetoacetyl group modification in the acetoacetyl group-containing PVA is typically 0.1 mol% or more, preferably 0.1 to 40 mol%, more preferably 1 to 20%, and still more preferably 2 to 2 mol%. 7 mol%. When the degree of modification is less than 0.1 mol%, the effect of modification (for example, improvement in water resistance) may be insufficient. If the degree of modification exceeds 40 mol%, the water resistance is not improved further. The degree of acetoacetyl modification of PVA can be measured by NMR.

  The adhesive composition may contain a crosslinking agent. Although a crosslinking agent is not limited, It is a compound which has at least two functional groups which show the reactivity with respect to PVA-type resin.

  Crosslinking agents include, for example, ethylenediamine, triethylenediamine, hexamethylenediamine and other alkylenediamines having an alkylene group and two amino groups; tolylene diisocyanate, hydrogenated tolylene diisocyanate, trimethylolpropane tolylene diisocyanate adduct, triphenylmethane Isocyanates such as triisocyanate, methylene bis (4-phenylmethane triisocyanate), isophorone diisocyanate, and their ketoxime block or phenol block; ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin Triglycidyl ether, 1,6-hexanediol diglycidyl ether, trime Epoxy such as roll propane triglycidyl ether, diglycidyl aniline, diglycidyl amine; monoaldehyde such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde; glyoxal, malondialdehyde, succindialdehyde, glutardialdehyde, maleindialdehyde, phthalate Dialdehydes such as dialdehydes; amino-formaldehyde resins such as methylol urea, methylol melamine, alkylated methylol urea, alkylated methylol melamine, acetoguanamine, condensates of benzoguanamine and formaldehyde; sodium, potassium, magnesium, calcium, aluminum, Salts and oxides of monovalent to trivalent metals such as iron and nickel.

  Of these, amino-formaldehyde resin and dialdehyde are preferable as the crosslinking agent. The amino-formaldehyde resin preferably has a methylol group, and methylol melamine is preferred. The dialdehyde is preferably glyoxal.

  The compounding quantity of the crosslinking agent in an adhesive composition can be suitably set according to the kind of PVA-type resin. Typically, it is about 10 to 60 parts by weight with respect to 100 parts by weight of the PVA resin, and preferably 20 to 50 parts by weight. In this range, good adhesion can be obtained. When the amount of the crosslinking agent is excessively large, the reaction via the crosslinking agent proceeds in a short time, and thus the adhesive composition tends to gel. For this reason, the pot life (pot life) as an adhesive composition becomes extremely short, and industrial use may become difficult.

  The adhesive composition may contain a metal compound colloid. The metal compound colloid may be a colloid in which particles of a metal compound are dispersed in a dispersion medium. The metal compound colloid can be a permanent colloid due to electrostatic stabilization due to mutual repulsion of the same type of charge that the particles have. By including the metal compound colloid in the adhesive composition, for example, the stability of the adhesive composition is improved even when the amount of the crosslinking agent is large.

  The average particle diameter of the colloidal particles in the metal compound colloid can be set within a range that does not adversely affect the optical characteristics (for example, polarization characteristics) of the polarizing plate. The average particle size of the colloidal particles is preferably 1 to 100 nm, and more preferably 1 to 50 nm.

  The average particle size of the colloidal particles can be measured by the same method as the method for determining the average primary particle size of the fine particles described above.

  In these ranges, the colloidal particles can be uniformly dispersed in the adhesive layer. Thereby, adhesiveness is ensured and occurrence of knick defects is suppressed. When a knick defect occurs, for example, light leakage occurs in an image display device incorporating the polarizing plate.

  The metal compound is not limited, for example, oxides such as alumina, silica, zirconia, and titania; metal salts such as aluminum silicate, calcium carbonate, magnesium silicate, zinc carbonate, barium carbonate, calcium phosphate; celite, talc, clay, It is a mineral such as kaolin. A metal compound colloid having a positive charge is preferred. The metal compound that becomes a positively charged colloid is preferably alumina or titania, and particularly preferably alumina.

  The metal compound colloid is typically a colloidal solution dispersed in a dispersion medium. The dispersion medium is, for example, water or alcohol. The solid content concentration in the colloidal solution is typically about 1 to 50% by weight, and preferably 1 to 30% by weight. The colloidal solution may contain an acid such as nitric acid, hydrochloric acid or acetic acid as a stabilizer.

  The compounding amount of the metal compound colloid in the adhesive composition (in terms of solid content) is preferably 200 parts by weight or less, more preferably 10 to 200 parts by weight, and further preferably 20 to 175 parts by weight with respect to 100 parts by weight of the PVA resin. Preferably, 30 to 150 parts by weight are particularly preferable. In these ranges, the occurrence of nick defects is further suppressed while the adhesiveness of the adhesive composition is more reliable.

  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 stabilizer such as a heat stabilizer and a hydrolysis stabilizer. You may go out.

  The adhesive composition is preferably an aqueous solution (resin solution). The concentration of the resin in the aqueous solution is preferably from 0.1 to 15% by weight, and more preferably from 0.5 to 10% by weight, from the viewpoint of the coating property and the standing stability of the composition.

  The viscosity of the aqueous solution is preferably 1 to 50 mPa · s. When the adhesive composition contains a metal compound colloid, even if the viscosity is as low as 1 to 20 mPa · s, generation of nick defects is effectively suppressed.

  2-6 are preferable, as for pH of aqueous solution, 2.5-5 are more preferable, 3-5 are more preferable, and 3.5-4.5 are especially preferable. In general, the surface charge of the metal compound colloid is adjusted by adjusting the pH of the aqueous solution. The surface charge is preferably a positive charge. Due to the positive charge, the occurrence of knick defects is further suppressed. The surface charge of the metal compound colloid can be confirmed, for example, by measuring the zeta potential with a zeta potential measuring device.

  The adhesive composition which is an aqueous solution (resin solution) can be formed by a known method. When the adhesive composition contains a cross-linking agent and a metal compound colloid, for example, a method of mixing the metal compound colloid in a solution in which a PVA resin and a cross-linking agent are mixed and adjusted to an appropriate concentration can be used. After mixing the PVA-based resin and the metal compound colloid, the cross-linking agent may be mixed in consideration of the use time of the adhesive composition. The concentration of the aqueous solution can be adjusted after preparing the aqueous solution.

  The thickness of the adhesive layer (adhesive layer) formed from the adhesive composition can be appropriately set according to the composition of the composition. The thickness is preferably 10 to 300 nm, more preferably 10 to 200 nm, and particularly preferably 20 to 150 nm. In this range, the adhesive layer (adhesive layer) exhibits a sufficient adhesive force.

[3. (Image display device)
The image display device of the present invention includes the polarizing plate according to the present invention. The image display device is, for example, an electroluminescence (EL) display panel, a plasma display panel (PDP), a field emission display (FED), or an LCD.

  The configuration of the image display device including the polarizing plate according to the present invention (the image display device of the present invention) is not particularly limited, and members such as a power source, a backlight unit, and an operation unit may be appropriately provided as necessary.

[4. Manufacturing method of optical film]
The manufacturing method of the optical film concerning this invention apply | coats the easily bonding composition containing a polyester-acryl composite resin (B) to the main surface (surface) of an acrylic resin film, and forms the coating film of the said composition. The process (application | coating process) and the process (drying process) of drying the formed coating film and forming the easily bonding layer containing the said polyester-acrylic composite resin (B) on the said surface are included. The easy-adhesion composition may contain the fine particles described above.

  In the method for producing an optical film according to the present invention, an optical film composed of an acrylic resin film having an easy-adhesion layer containing the polyester-acrylic composite resin (B) on the main surface (surface) (the optical film of the present invention). Film) is formed. The easy adhesion layer contains the resin contained in the easy adhesion composition.

  In the coating step, a coating film of the easy-adhesive composition is formed on at least one main surface (surface) of the acrylic resin film. Typically, the coating film is formed on one main surface (surface) of the acrylic resin film.

  A known method can be applied to the method of applying the easy-adhesion composition in the application step. Examples of the method 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 thickness of the coating film formed in the coating step can be appropriately adjusted according to the thickness required when the coating film becomes an easy-adhesion layer.

It is preferable that the main surface (surface) to which the easily bonding composition in an acrylic resin film is apply | coated is surface-treated. The surface treatment is as described above, but corona discharge treatment and plasma treatment are preferred. The conditions for the corona discharge treatment are not limited. Electron irradiation amount of the corona discharge treatment is preferably 50~150W / ^{m 2} / min, 70~100W / ^{m 2} / min is more preferred.

  What is necessary is just to follow a well-known method for a drying process. The drying temperature is typically 50 ° C. or higher, preferably 90 ° C. or higher, and more preferably 110 ° C. or higher. By setting the drying temperature within these ranges, for example, an optical film excellent in color resistance (particularly in an environment of high temperature and high humidity) can be obtained. The upper limit of the drying temperature is preferably 200 ° C. or lower, and more preferably 180 ° C. or lower.

  When producing an optical film that is a stretched film from an unstretched acrylic resin film by the production method of the present invention, and when producing an optical film that is a biaxially stretched film from a uniaxially stretched acrylic resin film, these acrylics are used. It is necessary to stretch the resin film at some point. The acrylic resin film may be stretched before the easy-adhesion layer is formed or after the easy-adhesion layer is formed. The formation of the easy-adhesion layer and the stretching of the acrylic resin film can be performed simultaneously.

  The acrylic resin film may be stretched according to a known method. Stretching is, for example, uniaxial stretching or biaxial stretching.

  The uniaxial stretching is typically free end uniaxial stretching in which the change in the width direction (TD direction) of the acrylic resin film is free. The fixed end uniaxial stretching which fixed the change of the width direction of the acrylic resin film may be sufficient.

  The biaxial stretching is typically sequential biaxial stretching, but simultaneous biaxial stretching in which longitudinal and transverse stretching are simultaneously performed can also be suitably used. Furthermore, the film roll may be stretched in an oblique direction. In the present specification, stretching in the flow direction (MD direction) of the acrylic resin film is referred to as longitudinal stretching, and stretching in the width direction (TD direction) is referred to as lateral stretching. In the case of a strip-shaped acrylic resin film, the MD direction is the longitudinal direction of the film.

  A known stretching machine can be used for stretching the acrylic resin film. The longitudinal stretching machine is not particularly limited, but an oven stretching machine is preferable.

  The oven vertical stretching machine is generally composed of an oven and transport rolls provided on the inlet side and the outlet side of the oven, respectively. The resin film is stretched in the transport direction by giving a peripheral speed difference between the transport roll on the entrance side of the oven and the transport roll on the exit side.

  The transverse stretching machine is not particularly limited, but a tenter stretching machine is preferable. The tenter stretching machine may be either a grip type or a pin type, but the grip type is preferable because the resin film hardly tears. A grip-type tenter stretching machine is generally composed of a clip traveling device for transverse stretching and an oven. In the clip traveling device, the resin film is conveyed in a state where the lateral end of the resin film is sandwiched between the clips. At this time, the resin rail is stretched laterally by opening the guide rail of the clip traveling device and widening the distance between the left and right two rows of clips. In the grip-type tenter stretching machine, simultaneous biaxial stretching is also possible by providing a clip expansion / contraction function with respect to the transport direction of the resin film. Moreover, the diagonal stretcher | stretcher which carries out the tension | pulling stretching in the conveyance direction of the said film at a different speed on the right and left of the extending direction of the resin film may be used.

  The stretching temperature is preferably in the vicinity of Tg of the acrylic resin constituting the acrylic resin film. Specifically, the range of Tg-30 ° C to Tg + 100 ° C is preferable, and the range of Tg-20 ° C to Tg + 80 ° C is more preferable. When the stretching temperature is lower than Tg-30 ° C, a sufficient stretching ratio may not be ensured. If the stretching temperature exceeds Tg + 100 ° C., the resin constituting the film 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. When the draw ratio is less than 1.1 times, the optical film characteristics expected by stretching, for example, toughness, may not be realized. On the other hand, when the draw ratio exceeds 25 times, the effect of improving the properties of the optical film is usually not obtained any more.

  The stretching speed is preferably 10 to 20,000% / min, more preferably 100 to 10,000% / min for stretching in one direction. When the stretching speed is less than 10% / min, the time required for stretching the film becomes excessively long, and the production cost of the optical film may increase. If the stretching speed exceeds 20,000% / min, the film may break.

  When forming an easily bonding layer and extending | stretching an acrylic resin film simultaneously, what is necessary is just to extend | stretch the acrylic resin film in which the coating film of the easily bonding composition was formed in a heating atmosphere after an application | coating process, for example. Due to the heat applied to the film for stretching, the coating film of the easy-adhesive composition formed on the surface of the acrylic resin film is dried to form an easy-adhesive layer. In addition, since Tg of an acrylic resin film is 100 degreeC or more normally, the extending | stretching temperature mentioned above is high enough for an easily bonding layer to be formed from the coating film of an easily bonding composition.

  The acrylic resin film that forms the coating film of the easy-adhesive composition in the coating step may be an unstretched film or a stretched film that has already been stretched. When the acrylic resin film that forms the coating film is a strip-shaped uniaxially stretched film and an optical film that is a biaxially stretched film is manufactured, the direction of uniaxial stretching is the MD direction of the film, and after the coating film is formed The stretching direction is preferably the TD direction. Thereby, an efficient optical film can be manufactured.

  When forming an acrylic resin film by melt extrusion, the process from formation of an acrylic resin film to obtaining an optical film which is a stretched film can be continuously performed. In this case, it is preferable to perform continuously the process of apply | coating an easily bonding composition to the surface of an acrylic resin film, and the process of extending | stretching the acrylic resin film which apply | coated the easily bonding composition in a heating atmosphere. Such an easy-adhesion composition coating step that is continuously performed is referred to as in-line coating.

  When producing an optical film that is a biaxially stretched film by the production method of the present invention, a step of stretching an unstretched film to make an acrylic resin film that is a uniaxially stretched film, an easily adhesive composition on the surface of the acrylic resin film It is particularly preferable to continuously perform the step of coating and the step of stretching the acrylic resin film coated with the easy-adhesive composition in a heated atmosphere.

  Furthermore, when performing surface treatments such as corona discharge treatment and plasma treatment on the acrylic resin film, a step of drawing an unstretched film to obtain an acrylic resin film that is a uniaxially stretched film, the surface of the acrylic resin film being a surface The process of processing, the process of apply | coating an easily bonding composition to the said surface of the surface-treated acrylic resin film, and the process of extending | stretching the acrylic resin film which apply | coated the easily bonding composition in a heating atmosphere are performed continuously. preferable.

  The production method of the present invention may include any step other than the steps described above as long as the effect of the present invention is obtained. This step is, for example, a step of laminating a further layer (for example, a resin layer) on the formed optical film, or a step of performing post-processing such as coating treatment or surface treatment on the formed optical film.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to the following examples. Initially, the evaluation method of the polymer, the optical film, and the optical film roll which were produced in the present Example is shown.

System: Tosoh GPC system HLC-8220
Measurement side column configuration Guard column: Tosoh, TSK guard column Super HZ-L
-Separation column: Tosoh, TSKgel SuperHZM-M 2 in series connection Reference side column configuration-Reference column: Tosoh, TSKgel SuperH-RC
Developing solvent: Chloroform (Wako Pure Chemical Industries, special grade)
Flow rate of developing solvent: 0.6 mL / min Standard sample: TSK standard polystyrene (manufactured by Tosoh, PS-oligomer kit)
Column temperature: 40 ° C
[Glass transition temperature (Tg)]
The Tg of the polymer was determined by the starting point method in accordance with JIS K7121 regulations. Specifically, a differential scanning calorimeter (manufactured by Rigaku, DSC-8230) is used, and a sample of about 10 mg is heated from normal temperature to 200 ° C. (temperature increase rate: 20 ° C./min) in a nitrogen gas atmosphere. The DSC curve was evaluated. Α-alumina was used as a reference.

[Film thickness]
The thickness of the film was measured using a Digimatic micrometer (manufactured by Mitutoyo Corporation). Thereafter, a sample for measuring and evaluating the physical properties of the film including the physical properties indicating the evaluation method was obtained from the central portion in the width direction of the film.

[Average particle size and particle size distribution of fine particles]
The average particle size and particle size distribution of the fine particles were evaluated using a particle size distribution measuring device (manufactured by Particle Sizing Systems, Submicron Particle Sizer NICOM 380). Specifically, for the fine particles in a state dispersed in water, an equivalent spherical distribution in a range of 100 nm or more in primary particle diameter is measured with the measuring device, and the obtained distribution is integrated from the large particle side. The particle diameter of the particles having an integrated volume fraction of 50% was determined and used as the average primary particle diameter (d50) of the fine particles. Separately from this, the particle diameter (d25) of particles having an integrated volume fraction of 25% and the particle diameter (d75) of 75% accumulated from the large particle side in the distribution are obtained, and the ratio (d25 / d75) Was the particle size distribution of the fine particles.

[Haze]
The haze of the produced film was determined using a turbidimeter (Nippon Denshoku Industries Co., Ltd., NDH-5000) in accordance with the provisions of JIS K7136.

[Light transmittance at a wavelength of 380 nm]
The light transmittance at a wavelength of 380 nm was measured using an ultraviolet-visible spectrophotometer (manufactured by Shimadzu Corporation, UV-3100).

[Hard coat layer adhesion]
A cross cut test was performed in accordance with JIS K5400 3.5. Specifically, a 1 mm square grid cut was made with a sharp blade on the hard coat layer surface, and a cellophane tape having a width of 25 mm in accordance with JIS Z1522 was adhered with a wooden spatula, and then the cellophane tape was peeled off. . The number of remaining squares out of the created 100 squares is shown in the “Adhesion” column of Tables 1 and 2 below.

  The cellophane tape is a commercially available cellophane tape that has passed JIS Z1522.

[Adhesion with adhesive layer]
A polyvinyl alcohol resin (average polymerization degree 1200) was dissolved in pure water to obtain an adhesive composition having a solid content of 4%. The obtained adhesive composition was applied to the easy-adhesion layer (b) formed on the surface of the optical film opposite to the surface on which the hard coat layer was formed so that the thickness after drying was 50 nm. Then, it was put into an 80 ° C. hot air dryer for 5 minutes and dried to obtain a film.

Using the film obtained by the above method as a test sample, a cross-cut test was performed in accordance with JIS K5400 3.5. Specifically, a 1 mm square grid cut was made with a sharp blade on the adhesive layer surface of the test sample, and then a cellophane tape having a width of 25 mm in accordance with JIS Z1522 was adhered with a wooden spatula. Thereafter, the cellophane tape was removed, and the state of the layer was observed. The evaluation criteria are as follows.
○: Peeling was not confirmed ×: Peeling was confirmed [Folding resistance]
The folding strength of the film was measured according to JIS P8115. Specifically, two types of test films having a length of 90 mm and a width of 15 mm, whose longitudinal directions are the MD direction and the TD direction, were used after being allowed to stand at 23 ° C. and 50% RH for 1 hour or longer. Using a folding tester (manufactured by Tester Sangyo Co., Ltd., model BE-201), the test was performed under the condition of a load of 200 g so that the fold line was parallel to the film flow direction during film formation, and five sample films The average value of the number of times until fracture occurred was taken as the measurement result.

(Production Example 1)
In a reaction kettle equipped with a stirrer, temperature sensor, cooling pipe and nitrogen introduction pipe, 40 parts by weight of methyl methacrylate (MMA), 10 parts by weight of methyl 2- (hydroxymethyl) acrylate (MHMA), and toluene 50 as a polymerization solvent Part by weight and 0.025 part by weight of an antioxidant (Adeka Stub 2112, manufactured by ADEKA) were charged, and the temperature was raised to 105 ° C. while passing nitrogen through this. At the start of the reflux accompanying the temperature rise, 0.05 parts by weight of t-amylperoxyisononanoate (manufactured by Arkema Yoshitomi, trade name: Luperox 570) was added as a polymerization initiator, and the t-amylperoxyisononoate was added. While 0.10 parts by weight of nanoate was added dropwise over 2 hours, solution polymerization was allowed to proceed under reflux at about 105 to 110 ° C., followed by further aging for 4 hours.

  Next, 0.05 part by weight of stearyl phosphate (manufactured by Sakai Chemical Industry Co., Ltd., Phoslex A-18) is added to the obtained polymerization solution as a catalyst for the cyclization condensation reaction (cyclization catalyst), and about 90 to 110 ° C. The cyclization condensation reaction for forming a lactone ring structure was allowed to proceed for 2 hours under reflux.

  Next, the polymer solution obtained by the cyclization condensation reaction was passed through a multi-tube heat exchanger heated to 240 ° C., and then the cyclization condensation reaction was completed, and then the barrel temperature was 240 ° C. and the degree of vacuum was 13.3 to 400 hPa. (10 to 300 mmHg), 1 rear vent and 4 fore vents (referred to as the first, second, third and fourth vents from the upstream side), and a side feeder between the third vent and the fourth vent 88 parts / hour (resin amount conversion) in a vent type screw twin screw extruder (L / D = 52) provided with a leaf disk type polymer filter (filtration accuracy 5 μm) at the tip. Introduced at a rate and devolatilized.

  At that time, after the second vent at a charging rate of 1.3 parts / hour of ion-exchanged water, a third prepared cyclization catalyst deactivator solution was prepared at a charging rate of 0.6 parts / hour. After the vent, a mixed solution of an ultraviolet absorber and an antioxidant was added after the fourth vent at a rate of 2.7 parts / hour.

  In the cyclization catalyst deactivator solution, 1.0 part by weight of calcium octylate (manufactured by Nippon Chemical Industry Co., Ltd., 5% by weight of Nikka octix calcium) as a deactivator is dissolved in 1.8 parts by weight of toluene. Was used.

  In the mixed solution of the ultraviolet absorber and the antioxidant, 0.1 part by weight of a phenolic antioxidant (manufactured by BASF Japan, Irganox 1010) and 0.1 part by weight of a sulfur-based antioxidant (manufactured by ADEKA, Adeka Stub AO-412S), 8.55 parts by weight of an ultraviolet absorber (manufactured by BASF Japan, Tinuvin 477), and a solution dissolved in 3.56 parts by weight of toluene were used.

  In addition, at the time of devolatilization, pellets of styrene-acrylonitrile copolymer (AS resin: ratio of styrene unit / acrylonitrile unit is 73% by weight / 27% by weight, weight average molecular weight is 220,000) from the side feeder. , And was charged at a loading speed of 12 parts / hour.

  After completion of devolatilization, the resin in the molten state remaining in the extruder is discharged while filtering through a polymer filter from the tip of the extruder, pelletized by a pelletizer, and has a lactone ring structure in the main chain (meta) An acrylic resin transparent pellet (A1) containing an acrylic polymer as a main component (content: 78% by weight) and further containing a styrene-acrylonitrile copolymer at a content of 12% by weight was obtained. The acrylic resin constituting the pellet (A1) had a Tg of 124 ° C. and a weight average molecular weight of 149,000.

  Next, the produced pellet (A1) was melt-extruded from a T-die at 280 ° C. using a single screw extruder, and discharged onto a 110 ° C. cooling roll to form a film having a thickness of 174 μm. . Next, the film-formed film was uniaxially stretched at 136 ° C. in the MD direction so that the stretch ratio was 2.2 times to obtain a longitudinally stretched film (F1) having a thickness of 116 μm.

(Production Example 2)
Acrylic resin (manufactured by Daicel-Evonik, Pleximimide 8813), the main component of which has a glutarimide structure in the main chain, is melt-extruded from a T-die at 280 ° C using a single screw extruder. The film was discharged onto a cooling roll at 110 ° C. to form a film having a thickness of 174 μm. Next, the film-formed film was uniaxially stretched at 142 ° C. in the MD direction so that the stretch ratio was 2.2 times to obtain a longitudinally stretched film (F2) having a thickness of 116 μm.

(Production Example 3)
Polyester-acrylic composite resin having epoxy group and carboxyl group (Takamatsu Yushi Co., Ltd., Pesresin A-647GEX, solid content 20% by weight), emulsion containing amorphous silica fine particles (Nippon Shokubai Co., Ltd., Seahoster KE-W10) , Average particle size (primary particle size) 0.11 μm, particle size distribution 1.1, solid content 15% by weight) 1.0 part by weight and 74 parts by weight of pure water are mixed to facilitate adhesion as an emulsion dispersion A composition (B1) was obtained.

(Production Example 4)
Polyester-acrylic composite resin having epoxy group and carboxyl group (Takamatsu Yushi Co., Ltd., Pesresin A-645GEX, solid content 20% by weight), emulsion containing amorphous silica fine particles (Nippon Shokubai Co., Ltd., Seahoster KE-W10) , Average particle size (primary particle size) 0.11 μm, particle size distribution 1.1, solid content 15% by weight) 1.0 part by weight and 74 parts by weight of pure water are mixed to facilitate adhesion as an emulsion dispersion A composition (B2) was obtained.

(Production Example 5)
Polyester-acrylic composite resin having an epoxy group and a carboxyl group (manufactured by Takamatsu Yushi Co., Ltd., Pesresin A-645GLX, solid content 20% by weight), 75 parts by weight, emulsion containing amorphous silica fine particles (Nippon Shokubai Co., Ltd., Seahoster KE-W10) , Average particle size (primary particle size) 0.11 μm, particle size distribution 1.1, solid content 15% by weight) 1.0 part by weight and 74 parts by weight of pure water are mixed to facilitate adhesion as an emulsion dispersion A composition (B3) was obtained.

(Production Example 6)
Polyester-acrylic composite resin having an epoxy group and a carboxyl group (Takamatsu Yushi Co., Ltd., Pesresin A-647GEX, solid content 20% by weight) 37.5 parts by weight, Polyester-acrylic composite resin (Takamatsu Yushi Co., Ltd., Pesresin) A-645GH, solid content 30 wt%) 25 parts by weight, emulsion containing amorphous silica fine particles (Nippon Shokubai Co., Ltd., Seahoster KE-W10, average particle size (primary particle size) 0.11 μm, particle size distribution 1.1, solid content 15 parts by weight) 1.0 part by weight and 86.5 parts by weight of pure water were mixed to obtain an easy-adhesion composition (B4) as an emulsion dispersion.

(Production Example 7)
Contains 23 parts by weight of urethane resin (Daiichi Kogyo Seiyaku, Superflex 210, solid content 35% by weight), 16 parts by weight of cross-linking agent (manufactured by Nippon Shokubai, Epocross WS-700, solid content 25% by weight), and amorphous silica fine particles. 0.03 part by weight of emulsion (Nippon Shokubai Co., Ltd., Seahoster KE-W30, average particle size (primary particle size) 0.28 μm, particle size distribution 1.1, solid content 20% by weight) and 61 parts by weight of pure water were mixed. The easy-adhesion composition (B5) which is an emulsion-like dispersion was obtained.

(Production Example 8)
Hard coat by mixing 15 parts by weight of tetrafunctional acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., AD-TMP), 0.6 parts by weight of photopolymerization initiator (manufactured by Ciba Specialty Chemicals, Irgacure 184), and 14.4 parts by weight of methyl ethyl ketone. Coating composition (C1) was obtained.

(Production Example 9)
In a reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introduction pipe, 229.6 parts by weight of methyl methacrylate (MMA), 33 parts by weight of methyl 2- (hydroxymethyl) acrylate (MHMA), as a polymerization solvent 248.6 parts by weight of toluene, 0.138 parts by weight of an antioxidant (Adeka Stub 2112, manufactured by ADEKA) and 0.1925 parts by weight of n-dodecyl mercaptan were charged, and the temperature was raised to 105 ° C. while passing nitrogen through the mixture.

  When refluxing with increasing temperature began, 0.2838 parts by weight of t-amylperoxyisononanoate (manufactured by Arkema Yoshitomi, trade name: Luperox 570) was added as a polymerization initiator, and the t-amylperoxyisonono While adding 0.5646 parts by weight of nanoate and 12.375 parts by weight of styrene dropwise over 2 hours, solution polymerization was allowed to proceed under reflux at about 105 to 110 ° C., followed by further aging for 4 hours.

  Next, 0.206 parts by weight of stearyl phosphate (manufactured by Sakai Chemical Industry, Phoslex A-18) is added to the obtained polymerization solution as a catalyst for the cyclization condensation reaction (cyclization catalyst), and about 90 to 110 ° C. The cyclization condensation reaction for forming a lactone ring structure was allowed to proceed for 2 hours under reflux.

  Next, the polymer solution obtained by the cyclization condensation reaction was completed through a multi-tube heat exchanger heated to 240 ° C., and then the barrel temperature was 250 ° C. and the degree of vacuum was 13.3 to 400 hPa. (10 to 300 mmHg), 1 rear vent and 4 fore vents (referred to as the first, second, third and fourth vents from the upstream side), and a side feeder between the third vent and the fourth vent 31.2 parts / hour (resin amount conversion) in a vent type screw twin screw extruder (L / D = 52) provided with a leaf disk type polymer filter (filtration accuracy 5 μm) at the tip. It was introduced at a treatment rate and devolatilized.

  At that time, after the second vent at a charging rate of 0.47 parts / hour of ion-exchanged water, a third prepared cyclization catalyst deactivator solution was prepared at a charging rate of 0.18 parts / hour. After the vent, the ultraviolet absorbent solution was added after the fourth vent at a rate of 0.59 parts / hour.

  In the cyclization catalyst deactivator solution, a solution obtained by dissolving 53.4 parts by weight of calcium octylate (made by Nippon Chemical Industry Co., Ltd., 5% by weight of Nikka octix calcium) as a deactivator in 124.5 parts by weight of toluene. Was used. As the ultraviolet absorbent solution, a solution prepared by dissolving 0.66 parts by weight of an ultraviolet absorbent (manufactured by ADEKA, Adeka Stub LA-F70) in 1.23 parts by weight of toluene was used.

  After completion of devolatilization, the resin in the molten state remaining in the extruder is discharged while filtering through a polymer filter from the tip of the extruder, pelletized by a pelletizer, and has a lactone ring structure in the main chain (meta) A transparent pellet (A2) of an acrylic resin made of an acrylic polymer was obtained. The acrylic resin constituting the pellet (A2) had a Tg of 121 ° C. and a weight average molecular weight of 131,000.

  Next, the produced pellet (A2) was melt-extruded from a T die at 280 ° C. using a single screw extruder, and discharged onto a cooling roll at 110 ° C. to form a film having a thickness of 174 μm. . Next, the film-formed film was uniaxially stretched at 136 ° C. in the MD direction so that the stretch ratio was 2.2 times to obtain a longitudinally stretched film (F19) having a thickness of 116 μm.

(Production Example 10)
100 parts by weight of an acrylic resin (Sumitomo Chemical Co., Sumipex TR) mainly composed of a (meth) acrylic polymer having a glutaric anhydride structure in the main chain, and 0.66 parts by weight of an ultraviolet absorber (ADEKA, ADK STAB) LA-F70) was supplied to a twin screw extruder at 240 ° C. to obtain transparent acrylic resin pellets (A3) made of a (meth) acrylic polymer having a glutaric anhydride structure in the main chain.

  Subsequently, using a single-screw extruder, melt extrusion was performed from a T die at 260 ° C., and the film was discharged onto a cooling roll at 110 ° C. to form a film having a thickness of 174 μm. Next, the film formed was uniaxially stretched at 136 ° C. in the MD direction so that the stretch ratio was 2.2 times to obtain a longitudinally stretched film (F20) having a thickness of 116 μm.

(Production Example 11)
Polyester-acrylic composite resin having an epoxy group and a carboxyl group (Takamatsu Yushi Co., Ltd., Pesresin A-647GEX, solid content 20% by weight) 37.5 parts by weight, polyester having an epoxy group and having no carboxyl group -Emulsion containing acrylic composite resin (Takamatsu Yushi Co., Ltd., Pesresin A-645GH, solid content 30% by weight), amorphous silica fine particles (Nissan Chemical Industries, Snowtex XL, average particle size (primary particle size)) 50 nm, solid content 40 wt%) 0.375 parts by weight and pure water 237 parts by weight were mixed to obtain an easy-adhesion composition (B6) as an emulsion dispersion.

(Production Example 12)
Polyester-acrylic composite resin having epoxy group and carboxyl group (Takamatsu Yushi Co., Ltd., Pesresin A-647GEX, solid content 20% by weight) 30 parts by weight, polyester-acrylic having epoxy group and no carboxyl group 30 parts by weight of composite resin (Takamatsu Yushi Co., Ltd., Pesresin A-645GH, solid content 30% by weight), emulsion containing amorphous silica fine particles (Nippon Shokubai Co., Ltd., Seahoster KE-W10, average particle size (primary particle size)) 11 μm, particle size distribution 1.1, solid content 15% by weight) 1.0 part by weight and pure water 89 parts by weight were mixed to obtain an easy-adhesion composition (B7) as an emulsion dispersion.

(Production Example 13)
Polyester-acrylic composite resin having epoxy group and carboxyl group (Takamatsu Yushi Co., Ltd., Pesresin A-647GEX, solid content 20% by weight) 30 parts by weight, polyester-acrylic composite resin (Takamatsu Yushi Co., Ltd., epoxy group) An emulsion containing 36 parts by weight of pesresin A-647GH having no carboxyl group and a solid content of 25% by weight and amorphous silica fine particles (manufactured by Nippon Shokubai Co., Ltd., Seahoster KE-W10, average particle diameter (primary particle diameter)). 11 μm, particle size distribution 1.1, solid content 15% by weight) 1.0 part by weight and pure water 83 parts by weight were mixed to obtain an easy-adhesion composition (B8) as an emulsion dispersion.

(Production Example 14)
Polyester-acrylic composite resin having epoxy group and carboxyl group (Takamatsu Yushi Co., Ltd., Pesresin A-647GEX, solid content 20% by weight) 22.5 parts by weight, polyester having epoxy group and having no carboxyl group -Acrylic composite resin (Takamatsu Yushi Co., Ltd., Pesresin A-645GH, solid content 30 wt%) 35 parts by weight, emulsion containing amorphous silica fine particles (Nippon Shokubai Co., Ltd., Seahoster KE-W10, average particle size (primary particle size)) 0.11 μm, particle size distribution 1.1, solid content 15 wt%) 1.0 part by weight, emulsion containing amorphous silica fine particles (manufactured by Nissan Chemical Industries, Snowtex C, average particle size (primary particle size) 15 nm, solid content 20 wt%) 15 parts by weight and 76.5 parts by weight of pure water Was obtained that easy adhesion composition (B9).

(Production Example 15)
Urethane resin (Daiichi Kogyo Seiyaku Co., Ltd., Superflex 210, solid content 35% by weight) 36.4 parts by weight, Cross-linking agent (Nippon Shokubai, Epocros WS-700, solid content 25% by weight), 9 parts by weight, amorphous silica fine particles 1 part by weight of an emulsion (Nippon Shokubai Co., Ltd., Seahoster KE-W10, average particle size (primary particle size) 0.11 μm, particle size distribution 1.1, solid content 15% by weight) and 103.6 parts by weight of pure water Thus, an easy-adhesion composition (B10) which is an emulsion-like dispersion was obtained.

(Production Example 16)
60 parts by weight of a polyester resin (Takamatsu Yushi Co., Ltd., Pesresin A-640, solid content 25% by weight), an emulsion containing fine particles of amorphous silica (Nippon Shokubai Co., Ltd., Seahoster KE-W10, average particle size (primary particle size)) 11 μm, particle size distribution 1.1, solid content 15 wt%) and 1 part by weight of pure water and 89 parts by weight of pure water were mixed to obtain an easy-adhesion composition (B11) as an emulsion dispersion.

(Production Example 17)
Acrylic resin (manufactured by Nippon Shokubai Co., Ltd., Acryset WR705, solid content 31% by weight) 48.4 parts by weight, emulsion containing amorphous silica fine particles (manufactured by Nippon Shokubai Co., Ltd., Seahoster KE-W10, average particle size (primary particle size) 0.11 μm 1 part by weight, particle size distribution 1.1, solid content 15% by weight) and 100.6 parts by weight of pure water were mixed to obtain an easy-adhesion composition (B12) which is an emulsion-like dispersion.

(Production Example 18)
100 parts by weight of an acrylic resin (manufactured by Daicel-Evonik, Pleximimide 8813) mainly composed of a (meth) acrylic polymer having a glutarimide structure in the main chain, and 0.66 parts by weight of an ultraviolet absorber (manufactured by ADEKA, ADK STAB LA) -F70) was supplied to a twin screw extruder at 260 ° C. to obtain transparent acrylic resin pellets (A4) made of a (meth) acrylic polymer having a glutarimide structure in the main chain.

  Subsequently, using a single-screw extruder, melt extrusion was performed from a T die at 280 ° C., and then discharged onto a 110 ° C. cooling roll to form a film having a thickness of 174 μm. Next, the film formed was uniaxially stretched at 142 ° C. in the MD direction so that the stretch ratio was 2.2 times to obtain a longitudinally stretched film (F43) having a thickness of 116 μm.

Example 1
The easy-adhesion composition (B1) produced in Production Example 3 was applied to one main surface of the longitudinally stretched film (F1) produced in Production Example 1 so that the thickness of the coating film after drying was 260 nm. After that, a biaxially stretched optical film (F3) having an easy-adhesion layer (a) on one side is stretched uniaxially at 146 ° C. in the TD direction using a tenter stretching machine so that the stretching ratio is 2.8 times. Got. The haze of the obtained film (F3) was 41%.

  Next, the surface of the easy adhesion layer (a) on the film (F3) side of the coating composition (C1) prepared in Production Example 8 so that the thickness of the coating film after drying is 4 μm. It apply | coated to the surface on the opposite side (easy-adhesion layer surface), and it dried for 2 minutes at 100 degreeC.

Subsequently, the coating composition (C1) was cured by irradiating UV light with an integrated irradiation amount of 500 mJ / cm ² to obtain an optical film (F4) having a hard coat layer on the surface. The haze of the obtained film (F4) was 0.5%, and the light transmittance at a wavelength of 380 nm was 8%. The adhesion of the hard coat layer was 100. The folding strength was 360 times for MD and 316 times for TD.

(Example 2)
In place of the easy-adhesive composition (B1), an easy-adhesive layer (a) is formed on one side by performing the same operation as in Example 1 except that the easy-adhesive composition (B2) produced in Production Example 4 was used. A biaxially stretched optical film (F5) having an optical film and an optical film (F6) having a hard coat layer on the surface were obtained. The obtained films (F5) and (F6) had hazes of 23% and 0.3%, respectively, and the light transmittance at a wavelength of 380 nm was 8%. The adhesion of the hard coat layer was 100.

(Example 3)
In place of the easy-adhesive composition (B1), an easy-adhesive layer (a) is formed on one side by performing the same operation as in Example 1 except that the easy-adhesive composition (B3) produced in Production Example 5 was used. A biaxially-stretched optical film (F7) having a surface and an optical film (F8) having a hard coat layer on the surface were obtained. The hazes of the obtained films (F7) and (F8) were 0.4% and 0.5%, respectively, and the light transmittance at a wavelength of 380 nm was 8%. The adhesion of the hard coat layer was 90.

Example 4
An easy-adhesion layer (a) is formed on one side by performing the same operation as in Example 1 except that the easy-adhesion composition (B4) produced in Production Example 6 was used instead of the easy-adhesion composition (B1). A biaxially-stretched optical film (F9) having an optical film and an optical film (F10) having a hard coat layer on the surface were obtained. The hazes of the obtained films (F9) and (F10) were 0.6% and 0.5%, respectively, and the light transmittance at a wavelength of 380 nm was 8%. The adhesion of the hard coat layer was 100.

(Example 5)
The easy-adhesion composition (B4) produced in Production Example 6 was applied to one main surface of the longitudinally stretched film (F1) produced in Production Example 1 so that the thickness of the coating film after drying was 260 nm. The easy-adhesive composition (B5) produced in Production Example 7 was applied to the other main surface so that the thickness of the coating film after drying was 1250 nm.

  Subsequently, using a tenter stretching machine so that the stretching ratio is 2.8 times, the film is uniaxially stretched at 146 ° C. in the TD direction to obtain a biaxially stretched optical film (F11) having easy-adhesion layers on both sides. It was. That is, in the biaxially stretched optical film (F11), an easy-adhesion layer (a) is formed on one surface, and an easy-adhesion layer (on the surface opposite to the surface on which the easy-adhesion layer (a) is formed) b) is formed. The haze of the obtained film (F11) was 0.6%.

  Next, on the surface opposite to the biaxially stretched optical film (F11) side (easy-adhesive layer surface) of the easy-adhesive layer (a), the coating composition (C1) created in Production Example 8 is used. The coating film was dried so that the thickness of the coating film was 4 μm and dried at 100 ° C. for 2 minutes.

Subsequently, the coating film (C1) is cured by irradiating UV light with an integrated irradiation amount of 500 mJ / cm ² , having a hard coat layer on the surface and an easy-adhesion layer (b) on the opposite surface. (F12) was obtained.

  The haze of the obtained film (F12) was 0.5%, and the light transmittance at a wavelength of 380 nm was 8%. The adhesion of the hard coat layer was 100, and the adhesion of the adhesive layer was ○.

(Example 6)
The easy-adhesion composition (B4) produced in Production Example 6 was applied to one main surface of the longitudinally stretched film (F2) produced in Production Example 2 so that the thickness of the coating film after drying was 260 nm. Thereafter, a biaxially stretched optical film (F13) having an easy-adhesion layer (a) on one side is stretched uniaxially at 152 ° C. in the TD direction using a tenter stretching machine so that the stretching ratio is 2.8 times. Got. The haze of the obtained film (F13) was 2.7%.

  Next, the coating composition (C1) prepared in Production Example 8 is applied on the surface (easy-adhesion layer surface) opposite to the film (F13) side of the easy-adhesion layer (a) after drying. The film was applied to a thickness of 4 μm and dried at 100 ° C. for 2 minutes.

Subsequently, UV light with an integrated irradiation amount of 500 mJ / cm ² was irradiated to cure the coating composition (C1), thereby obtaining an optical film (F14) having a hard coat layer on the surface. The haze of the obtained film (F14) was 0.7%. The adhesion of the hard coat layer was 100.

(Example 7)
An easy-adhesive layer (a) is provided on one side by performing the same operation as in Example 4 except that the longitudinally stretched film (F19) produced in Production Example 9 was used instead of the longitudinally stretched film (F1). A biaxially stretched optical film (F21) and an optical film (F22) having a hard coat layer were obtained.

  The hazes of the obtained films (F21) and (F22) were 2.2% and 0.3%, respectively, and the adhesion of the hard coat layer was 100. The light transmittance at a wavelength of 380 nm was 8%.

(Example 8)
By replacing the longitudinally stretched film (F1) with the longitudinally stretched (F20) produced in Production Example 10, the same operation as in Example 4 was carried out, thereby providing an easily adhesive layer (a) on one side. An axial stretched optical film (F23) and an optical film (F24) having a hard coat layer were obtained.

  The hazes of the obtained films (F23) and (F24) were 2.5% and 0.3%, respectively, and the adhesion of the hard coat layer was 100. The light transmittance at a wavelength of 380 nm was 8%.

Example 9
The easy-adhesion composition (B6) produced in Production Example 11 was applied to one main surface of the longitudinally stretched film (F1) produced in Production Example 1 so that the thickness of the coating film after drying was 130 nm. Then, a fixed end uniaxial stretching was performed at 146 ° C. in the TD direction using a tenter so that the stretching ratio was 2.8 times, and a biaxially stretched optical film (F25) having an easy-adhesion layer (a) on one side was obtained. It was. The haze of the obtained film (F25) was 0.8%.

  Next, on the surface opposite to the biaxially stretched optical film (F25) side (easy-adhesive layer surface) of the easy-adhesive layer (a), the coating composition (C1) created in Production Example 8 is used. The coating film was dried so that the thickness of the coating film was 4 μm and dried at 100 ° C. for 2 minutes.

Subsequently, the coating composition (C1) was cured by irradiating UV light with an integrated irradiation amount of 500 mJ / cm ² to obtain an optical film (F26) having a hard coat layer on the surface. The haze of the obtained film (F26) was 0.2%, and the light transmittance at a wavelength of 380 nm was 8%. The adhesion of the hard coat layer was 100.

(Example 10)
An easy-adhesion layer (a) is formed on one side by performing the same operation as in Example 1 except that the easy-adhesion composition (B7) produced in Production Example 12 was used instead of the easy-adhesion composition (B1). A biaxially-stretched optical film (F27) having a hard coat layer and an optical film (F28) having a hard coat layer were obtained.

  The obtained films (F27) and (F28) had hazes of 1.2% and 0.2%, respectively, and the adhesion of the hard coat layer was 100. The light transmittance at a wavelength of 380 nm was 8%.

(Example 11)
An easy-adhesion layer (a) is formed on one side by performing the same operation as in Example 1 except that the easy-adhesion composition (B8) produced in Production Example 13 was used instead of the easy-adhesion composition (B1). A biaxially stretched optical film (F29) having a hard coat layer and an optical film (F30) having a hard coat layer were obtained.

  The hazes of the obtained films (F29) and (F30) were 0.6% and 0.2%, respectively, and the adhesion of the hard coat layer was 100. The light transmittance at a wavelength of 380 nm was 8%.

(Example 12)
An easy-adhesion layer (a) is formed on one side by performing the same operation as in Example 1 except that the easy-adhesion composition (B9) produced in Production Example 14 was used instead of the easy-adhesion composition (B1). A biaxially stretched optical film (F31) having an optical film and an optical film (F32) having a hard coat layer were obtained.

  The hazes of the obtained films (F31) and (F32) were 1.1% and 0.1%, respectively, and the adhesion of the hard coat layer was 100. The light transmittance at a wavelength of 380 nm was 8%.

(Example 13)
An easy-adhesion layer (a) is provided on one side by performing the same operation as in Example 6 except that the longitudinally stretched film (F43) produced in Production Example 18 was used instead of the longitudinally stretched film (F2). A biaxially stretched optical film (F44) and an optical film (F45) having a hard coat layer were obtained.

  The obtained films (F44) and (F45) had hazes of 2.8% and 0.2%, respectively, and the adhesion of the hard coat layer was 100. The light transmittance at a wavelength of 380 nm was 8%.

(Comparative Example 1)
The longitudinally stretched film (F1) produced in Production Example 1 is uniaxially stretched at 146 ° C. in the TD direction using a tenter stretching machine so that the stretching ratio is 2.8 times, and does not have an easy adhesion layer. A biaxially stretched optical film (F15) was obtained. The haze of the obtained film (F15) was 0.2%.

  Next, the coating composition (C1) prepared in Production Example 8 was applied to one main surface of the film (F15) so that the thickness of the coating film after drying was 4 μm, and dried at 100 ° C. for 2 minutes. did.

Subsequently, UV light with an integrated irradiation amount of 500 mJ / cm ² was irradiated to cure the coating composition (C1), and an optical film (F16) having a hard coat layer on the surface was obtained. The haze of the obtained film (F16) was 0.2%. The adhesion of the hard coat layer was 30. The folding strength was 287 times for MD and 245 times for TD.

(Comparative Example 2)
The longitudinally stretched film (F2) produced in Production Example 2 is uniaxially stretched at 152 ° C. in the TD direction using a tenter stretcher so that the stretch ratio is 2.8 times, and does not have an easy adhesion layer. A biaxially stretched optical film (F17) was obtained. The haze of the obtained film (F18) was 1.2%.

  Next, the coating composition (C1) prepared in Production Example 8 was applied to one main surface of the film (F17) so that the thickness of the coating film after drying was 4 μm, and dried at 100 ° C. for 2 minutes. did.

Subsequently, the coating composition (C1) was cured by irradiating UV light with an integrated irradiation amount of 500 mJ / cm ² to obtain an optical film (F18) having a hard coat layer on the surface. The haze of the obtained film (F18) was 0.8%. The adhesion of the hard coat layer was 30.

(Comparative Example 3)
Biaxially stretched optical material having no easy-adhesion layer by performing the same operation as in Comparative Example 1 except that the longitudinally stretched film (F19) produced in Production Example 9 was used instead of the longitudinally stretched film (F1). A film (F33) and an optical film (F34) having a hard coat layer were obtained. The obtained films (F33) and (F34) had hazes of 0.2% and 0.5%, respectively, and the adhesion of the hard coat layer was 20.

(Comparative Example 4)
Biaxially stretched optical material having no easy-adhesion layer by performing the same operation as Comparative Example 1 except that the longitudinally stretched film (F20) produced in Production Example 10 was used instead of the longitudinally stretched film (F1). A film (F35) and an optical film (F36) having a hard coat layer were obtained. The obtained films (F35) and (F36) had hazes of 0.2% and 0.7%, respectively, and the adhesion of the hard coat layer was 15.

(Comparative Example 5)
An easy-adhesion layer (a) is formed on one side by performing the same operation as in Example 1 except that the easy-adhesion composition (B10) produced in Production Example 15 was used instead of the easy-adhesion composition (B1). ) Having a biaxially stretched optical film (F37) and an optical film (F38) having a hard coat layer. The obtained films (F37) and (F38) had hazes of 0.2% and 1.3%, respectively, and the adhesion of the hard coat layer was 3.

(Comparative Example 6)
It replaces with an easily bonding composition (B1), and it has an easily bonding layer on the single side | surface by performing operation similar to Example 1 except having used the easily bonding composition (B11) manufactured by manufacture example 16. A biaxially stretched optical film (F39) and an optical film (F40) having a hard coat layer were obtained. The obtained films (F39) and (F40) had hazes of 0.5% and 1.2%, respectively, and the adhesion of the hard coat layer was 20.

(Comparative Example 7)
It replaces with an easily bonding composition (B1), and it has an easily bonding layer on the single side | surface by performing operation similar to Example 1 except having used the easily bonding composition (B12) manufactured by the manufacture example 17. A biaxially stretched optical film (F41) and an optical film (F42) having a hard coat layer were obtained. The obtained films (F41) and (F42) had hazes of 0.5% and 1.2%, respectively, and the adhesion of the hard coat layer was 12.

(Comparative Example 8)
Biaxially stretched optical material having no easy-adhesion layer by performing the same operation as in Comparative Example 2 except that the longitudinally stretched film (F43) produced in Production Example 18 was used instead of the longitudinally stretched film (F2). A film (F46) and an optical film (F47) having a hard coat layer were obtained. The obtained films (F46) and (F47) had hazes of 0.2% and 0.2%, respectively, and the adhesion of the hard coat layer was 30.

  The evaluation results of the optical films produced in each example and comparative example are shown in Tables 1 and 2 below. In addition, the adhesiveness of a hard-coat layer should just be 50% or more, and it is preferable that it is 90% or more.

  The optical film of the present invention is suitable for use in various protective films such as polarizer protective films, retardation films and polarizing films used in image display devices such as LCDs.

DESCRIPTION OF SYMBOLS 1a-1d ... Optical film of this invention 2 ... Acrylic resin film 3 ... Easy-adhesion layer (a)
4 ... Functional coating layer 5 ... Easy adhesion layer (b)
6 ... Adhesive layer 7 ... Other members 8 ... Polarizer 9 ... Adhesive layer

Claims (16)

  An optical film comprising an acrylic resin film made of an acrylic resin (A) and an easy-adhesion layer (a) containing a polyester-acrylic composite resin (B).   The optical film according to claim 1, wherein the polyester-acrylic composite resin (B) has an epoxy group.   The optical film according to claim 2, wherein the polyester-acrylic composite resin (B) further has a carboxyl group.   The optical film according to any one of claims 1 to 3, wherein the easy-adhesion layer (a) contains fine particles.   The average primary particle diameter of the fine particles contained in the easy-adhesion layer (a) is 300 nm or less, and the particle size distribution of the fine particles contained in the easy-adhesion layer (a) is 1.0 to 1.4. The optical film according to claim 4.   The easy-adhesion layer (a) is formed on one main surface of the acrylic resin film, and a functional coating layer is provided on the surface of the easy-adhesion layer (a) facing the surface on the acrylic resin film side. It forms, The optical film of any one of Claim 1 to 5 characterized by the above-mentioned.   The easy adhesion layer (b) is formed in the main surface on the opposite side to the surface in which the said easy adhesion layer (a) is formed of the said acrylic resin film, Any one of Claim 1 to 6 characterized by the above-mentioned. 2. The optical film according to item 1.   The optical film according to claim 7, wherein the easy adhesion layer (b) is a urethane resin layer.   The optical film according to claim 7 or 8, wherein an adhesive layer is formed on a surface of the easy-adhesion layer (b) facing the surface on the acrylic resin film side.   The optical film according to claim 1, wherein the acrylic resin film contains a (meth) acrylic polymer having a ring structure in the main chain.   11. The ring structure according to claim 10, wherein the ring structure is at least one selected from the group consisting of a maleic anhydride structure, an N-substituted maleimide structure, a glutaric anhydride structure, a glutarimide structure, and a lactone ring structure. Optical film.   The optical film according to any one of claims 1 to 11, wherein the light transmittance at 380 nm is 30% or less.   The optical film according to claim 12, wherein the acrylic resin film contains an ultraviolet absorber having a molecular weight of 600 or more.   A polarizer protective film comprising the optical film according to claim 1.   A polarizing plate comprising the optical film according to claim 1.   An image display device comprising the polarizing plate according to claim 15.

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