JP2015083335A - Laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate which has a high-hardness hard surface e.g. excellent in scratch resistance and flexibility and is good in visibility after a heat-moisture treatment, foreign matter detectability, hard coat adhesiveness, impact resistance and curling properties.SOLUTION: A laminate has a coating layer on both sides of a polyester film; films of a thickness of 125-350 μm are pasted to both sides of an adhesive layer; and the laminate has a hard coat layer of a thickness (after drying) of 2-100 μm on both sides of the exposed coating layer. The laminate has a total light transmittance of 90% or higher and a film haze change rate (ΔH) before and after a 100-h heat-moisture treatment in an atmosphere of 85°C and 85% RH of 1.5% or smaller.

Description

  INDUSTRIAL APPLICABILITY The present invention can be suitably used as a glass substitute in various fields such as in-vehicle use, building material use, optical use, for example, for display surface protection, and has high hardness with excellent scratch resistance and flexibility. The present invention relates to a laminate having a hard surface and good visibility after wet heat treatment, foreign matter detection, hard coat adhesion, impact resistance, and curling properties.

  Conventionally, an image display surface in an image display device such as a liquid crystal display or an organic EL display is required to have scratch resistance so as not to be damaged during use. Therefore, the scratch resistance of the image display surface of the image display device may be improved by using a hard coat film in which a hard coat layer is laminated on the surface of the base film.

  There are various methods for laminating a hard coat layer on a base film, such as a method of forming a harder resin layer on a base film using a photopolymerizable resin such as a thermosetting resin or an ultraviolet curable resin. A method has been proposed. Moreover, depending on the kind of hard coat layer, the flexibility as a laminate is insufficient when the polyester films are bonded together, and the hard coat layer may be cracked when the film laminate is folded ( For example, there is description in Patent Document 1).

  As an alternative to glass used for electronic parts, when the use of a polyester film laminate is assumed, the required characteristics are stable in an atmosphere of constant temperature and humidity (eg, 85 ° C., 85% RH, etc.). It is common to perform a reliability test to confirm that the

  In this case, in the laminate structure in which the polyester film is bonded through the pressure-sensitive adhesive layer, the low molecular weight substance and oligomer (mainly ester cyclic trimer) in the polyester film precipitate and crystallize after the wet heat treatment. As a result, the visibility may be reduced as the film haze increases.

  For this reason, when an oligomer precipitation prevention measure is taken, for example, when the oligomer precipitation prevention layer described in Patent Document 2 is laminated on the polyester film surface, oligomer precipitation is suppressed, but adhesion to the functional layer, for example, The adhesiveness to the hard coat layer is poor.

  On the other hand, when an easy-adhesion layer for a hard coat layer (for example, Patent Document 3) that is generally used is laminated on a polyester film, adhesion to the hard coat layer is good, but oligomer precipitation is prevented. The effect is inadequate. Therefore, when used as a constituent member of a polyester film laminate, it is necessary to have a coating layer that achieves a high level of conflicting properties such as prevention of oligomer precipitation of the polyester film after wet heat treatment and adhesion to the hard coat layer. Is in a situation.

JP2013-35210A Japanese Patent No. 5236586 JP 2010-89307 A

  The present invention has been made in view of the above circumstances, and the solution is to use a double-sided coated film as a constituent unit of a polyester film laminate having a coating layer having a specific configuration on both sides, for example, Provided is a polyester film laminate having a hard surface with high hardness excellent in scratch resistance and flexibility, and excellent visibility, foreign matter detection, hard coat adhesion, impact resistance, and curling properties after wet heat treatment. There is.

  As a result of intensive studies in view of the above circumstances, the present inventors have found that the above problems can be easily solved by a laminate having a specific configuration, and have completed the present invention.

  That is, the gist of the present invention is a laminate in which a film having a thickness of 125 to 350 μm having a coating layer on both sides of a polyester film is bonded to both sides of the pressure-sensitive adhesive layer. ) Has a hard coat layer of 2 to 100 μm, the total light transmittance of the laminate is 90% or more, and the film haze change of the laminate before and after wet heat treatment in an atmosphere of 85 ° C. and 85% RH for 100 hours It exists in the laminated body characterized by a rate ((DELTA) H) being 1.5% or less.

  According to the present invention, for example, as a substitute for glass, it has a hard surface with high hardness, excellent scratch resistance and flexibility, and visibility after wet heat treatment, UV absorption performance, hard coat adhesion, impact resistance Can provide a laminate having good properties and curling properties, and its industrial value is high.

Schematic explanatory drawing showing an example of the laminate of the present invention

  In the present invention, the polyester film constituting the laminate may be a single layer structure or a laminated structure. For example, a layer other than a two-layer or three-layer structure may be a four-layer or a layer as long as the gist of the present invention is not exceeded. It may be a multilayer having more than that, and is not particularly limited.

  The polyester used for the polyester film in the present invention may be a homopolyester or a copolyester. In the case of a homopolyester, those obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol are preferred. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Representative polyester includes polyethylene terephthalate (PET) and the like. On the other hand, examples of the dicarboxylic acid component of the copolyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and oxycarboxylic acid (eg, P-oxybenzoic acid). 1 type or 2 types or more are mentioned, As a glycol component, 1 type or 2 types or more, such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1, 4- cyclohexane dimethanol, neopentyl glycol, is mentioned. In any case, the polyester referred to in the present invention refers to a polyester which is polyethylene terephthalate or the like in which 60 mol% or more, preferably 80 mol% or more is an ethylene terephthalate unit.

  In the present invention, it is preferable to blend particles in the polyester layer mainly for the purpose of imparting slipperiness. The kind of the particle to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness. Specific examples thereof include silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, and magnesium phosphate. , Particles of kaolin, aluminum oxide, titanium oxide and the like. Further, the heat-resistant organic particles described in JP-B-59-5216, JP-A-59-217755 and the like may be used. Examples of other heat-resistant organic particles include thermosetting urea resins, thermosetting phenol resins, thermosetting epoxy resins, benzoguanamine resins, and the like. Furthermore, precipitated particles obtained by precipitating and finely dispersing a part of a metal compound such as a catalyst during the polyester production process can also be used.

  On the other hand, the shape of the particles to be used is not particularly limited, and any of a spherical shape, a block shape, a rod shape, a flat shape, and the like may be used. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc. These series of particles may be used in combination of two or more as required.

The average particle size of the particles contained in the polyester film is preferably in the range of 0.2 to 3.0 μm. When the average particle size is less than 0.2 μm, the film surface may be flattened and the winding characteristics in the film production process may be inferior. On the other hand, when the average particle size exceeds 3.0 μm, it may be difficult to adapt to applications in which visibility is important due to generation of bright spots due to particles contained in the film.

  Furthermore, the particle content in the polyester layer is usually in the range of 0.001 to 5% by weight, preferably 0.005 to 3% by weight. When the particle content is less than 0.001% by weight, the slipperiness of the film may be insufficient. On the other hand, when the content exceeds 5% by weight, the transparency of the film is insufficient. There is.

  The method for adding particles to the polyester layer is not particularly limited, and a conventionally known method can be adopted. For example, it can be added at any stage of producing the polyester constituting each layer, but preferably a polycondensation reaction may be carried out after the esterification stage or after the transesterification reaction.

  Also, a method of blending a slurry of particles dispersed in ethylene glycol or water with a vented kneading extruder and a polyester raw material, or a blending of dried particles and a polyester raw material using a kneading extruder. It is done by methods.

  In order to correspond to the use which requires weather resistance in the polyester film of the base material constituting the double-sided coated film of the present invention, it is preferable to contain an ultraviolet absorber. The ultraviolet absorber is not particularly limited as long as it is a compound having ultraviolet absorbing ability and can withstand the heat applied in the production process of the polyester film.

As the ultraviolet absorber, there are an organic ultraviolet absorber and an inorganic ultraviolet absorber. From the viewpoint of transparency, an organic ultraviolet absorber is preferable. Although it does not specifically limit as an organic type ultraviolet absorber, For example, a cyclic imino ester type, a benzotriazole type, a benzophenone type etc. are mentioned. From the viewpoint of durability, a cyclic imino ester type and a benzotriazole type are more preferable. It is also possible to use two or more ultraviolet absorbers in combination.

The benzotriazole-based UV absorber is not limited to the following, but, for example, 2- [2′-hydroxy-5 ′-(methacryloyloxymethyl) phenyl] -2
H-benzotriazole, 2- [2'-hydroxy-5 '-(methacryloyloxyethyl) phenyl] -2H-benzotriazole, 2- [2'-hydroxy-5'-(methacryloyloxypropyl) phenyl] -2H- Benzotriazole, 2- [2′-hydroxy-5 ′-(methacryloyloxyhexyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy-3′-tert-butyl-5 ′-(methacryloyloxyethyl) Phenyl] -2H-benzotriazole, 2- [2′-hydroxy-5′-ter
t-butyl-3 ′-(methacryloyloxyethyl) phenyl] -2H-benzotriazole, 2- [2′-hydroxy-5 ′-(methacryloyloxyethyl) phenyl] -5-chloro-2H-benzotriazole, 2- [2′-hydroxy-5 ′-(methacryloyloxyethyl) phenyl] -5-methoxy-2H-benzotriazole, 2- [2′-
Hydroxy-5 '-(methacryloyloxyethyl) phenyl] -5-cyano-2H-benzotriazole, 2- [2'-hydroxy-5'-(methacryloyloxyethyl) phenyl] -5-tert-butyl-2H-benzo And triazole, 2- [2′-hydroxy-5 ′-(methacryloyloxyethyl) phenyl] -5-nitro-2H-benzotriazole, and the like.

Examples of the cyclic imino ester-based ultraviolet absorber include, but are not limited to, 2-methyl-3,1-benzoxazin-4-one, 2-butyl-3,1-benzoxazine-4, for example. -One, 2-phenyl-3,1-benzoxazin-4-one, 2- (1- or 2-naphthyl) -3, 1-benzoxazin-4-one, 2- (4-biphenyl) -3, 1-benzoxazin-4-one, 2-p-nitrophenyl-3,1-benzoxazin-4-one, 2-m-nitrophenyl-3,1-benzoxazin-4-one, 2-p-benzoyl Phenyl-3,1-benzoxazin-4-one, 2-p-methoxyphenyl-3,1-benzoxazin-4-one, 2-o-methoxyphenyl-3,1-benzoxazin-4-one, 2-cyclohexyl-3,1-benzoxazin-4-one, 2-p- (or m-) phthalimidophenyl-3,1-benzoxazin-4-one, N-phenyl-4- (3,1-benzo Oxazin-4-on-2-yl) phthalimide, N-benzoyl-4- (3,1-benzoxazin-4-on-2-yl) aniline, N-benzoyl-N-methyl-4- (3,1 -Benzoxazin-4-one-2-yl) aniline, 2- (p- (N-methylcarbonyl) phenyl) -3,1-benzoxazin-4-one, 2,2'-bis (3,1- Benzoxazin-4-one), 2,2′-ethylenebis (3,1-benzoxazin-4-one), 2,2′-tetramethylenebis (3,1-benzoxazin-4-one), 2 , 2'-Decamire Bis (3,1-benzoxazin-4-one, 2,2'-p-phenylenebis (3,1-benzoxazin-4-one), 2,2'-m-phenylenebis (3,1-benzo Oxazin-4-one), 2,2 ′-(4,4′-diphenylene) bis (3,1-benzoxazin-4-one), 2,2 ′-(2,6- or 1,5-naphthylene) ) Bis (3,1-benzoxazin-4-one), 2,2 ′-(2-methyl-p-phenylene) bis (3,1-benzoxazin-4-one), 2,2 ′-(2 -Nitro-p-phenylene) bis (3,1-benzoxazin-4-one), 2,2 '-(2-chloro-p-phenylene) bis (3,1-benzoxazin-4-one), 2 , 2 '-(1,4-cyclohexylene) bis (3,1-benzoxazin-4-one ), 1,3,5-tri (3,1-benzoxazin-4-on-2-yl) benzene, 1,3,5-tri (3,1-benzoxazin-4-on-2-yl) Naphthalene, 2,4,6-tri (3,1-benzoxazin-4-on-2-yl) naphthalene, 2,8-dimethyl-4H, 6H-benzo (1,2-d; 5,4-d ') Bis (1,3) -oxazine-4,6-dione, 2,7-dimethyl-4H, 9H-benzo (1,2-d; 4,5-d') bis (1,3) -oxazine -4,9-dione, 2,8-diphenyl-4H, 8H-benzo (1,2-d; 5,4-d ') bis (1,3) -oxazine-4,6-dione, 2,7 -Diphenyl-4H, 9H-benzo (1,2-d; 4,5-d ') bis (1,3) -oxazine-4,6-dione, 6, '-Bis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6'-bis (2-ethyl-4H, 3,1-benzoxazin-4-one), 6,6 '-Bis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6'-methylenebis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6 '-Methylenebis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6'-ethylenebis (2-methyl-4H, 3,1-benzoxazin-4-one), 6, 6′-ethylenebis (2-phenyl-4H, 3,1-benzoxazin-4-one), 6,6′-butylenebis (2-methyl-4H, 3,1-benzoxazin-4-one), 6 , 6'-Butylenebis (2-phenyl-4H, 3,1-benzoo Xazin-4-one), 6,6′-oxybis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6′-oxybis (2-phenyl-4H, 3,1-benzo) Oxazin-4-one), 6,6′-sulfonylbis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6′-sulfonylbis (2-phenyl-4H, 3,1) -Benzoxazin-4-one), 6,6'-carbonylbis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,6'-carbonylbis (2-phenyl-4H, 3 , 1-benzoxazin-4-one), 7,7′-methylenebis (2-methyl-4H, 3,1-benzoxazin-4-one), 7,7′-methylenebis (2-phenyl-4H, 3 , 1-benzoxazin-4-one), , 7′-bis (2-methyl-4H, 3,1-benzoxazin-4-one), 7,7′-ethylenebis (2-methyl-4H, 3,1-benzoxazin-4-one), 7,7′-oxybis (2-methyl-4H, 3,1-benzoxazin-4-one), 7,7′-sulfonylbis (2-methyl-4H, 3,1-benzoxazin-4-one) 7,7′-carbonylbis (2-methyl-4H, 3,1-benzoxazin-4-one), 6,7′-bis (2-methyl-4H, 3,1-benzoxazin-4-one) ), 6,7′-bis (2-phenyl-4H, 3,1-benzoxazin-4-one, 6,7′-thylenebis (2-methyl-4H, 3,1-benzoxazin-4-one, 6,7'-methylenebis (2-phenyl-4H, 3,1-benzoxazi 4-one), and the like.

  Among the above compounds, when the color tone is taken into consideration, a benzoxazinone-based compound that is difficult to be yellowed is preferably used, and examples thereof include those represented by the following formula (1). .

  In the above formula, R represents a divalent aromatic hydrocarbon group, and X1 and X2 are each independently selected from hydrogen or the following functional group group, but are not necessarily limited thereto.

  Functional group: alkyl group, aryl group, heteroaryl group, halogen, alkoxyl group, aryloxy group, hydroxyl group, carboxyl group, ester group, nitro group Among the compounds represented by the above structural formula, in the present invention, 2,2- (1,4-phenylene) bis [4H-3,1-benzoxazin-4-one] is particularly preferred.

  The polyester film constituting the double-sided coated film of the present invention contains an ultraviolet absorber in a range of usually 0.10 to 5.0% by weight, preferably 0.20 to 3.0% by weight. When the UV absorber is less than 0.10% by weight, the dye in the filter may be deteriorated by the UV light transmitted through the polyester film. When the UV absorber is contained in an amount exceeding 5.0% by weight May bleed out the ultraviolet absorber on the surface, leading to deterioration of surface functionality such as adhesion deterioration.

  As for the polyester film which comprises the double-sided coating film of this invention, 2.0% or less is preferable about the light transmittance of wavelength 380 nm, More preferably, it is 1.0% or less. When the light transmittance at a wavelength of 380 nm is larger than 2.0%, it may be difficult to cope with the necessity of ultraviolet absorption performance in outdoor use such as for building materials.

  Moreover, it is preferable that the total light transmittance of the double-sided coated film in the present invention is 90% or more in order to be able to cope with applications that particularly require transparency, and more preferably 92% or more. When the total light transmittance is less than 90%, the transparency becomes insufficient, and for example, it may be difficult to cope with applications that place importance on visibility, such as glass replacement.

  In addition to the above-mentioned particles, conventionally known antioxidants, antistatic agents, thermal stabilizers, lubricants, dyes, pigments, and the like can be added to the polyester film in the present invention as necessary.

  The thickness of the double-sided coating film constituting the polyester film laminate of the present invention needs to be 125 to 350 μm, and preferably in the range of 188 to 300 μm. Outside the above range, it is not preferable in the use of the laminate of the present invention.

  Next, although the manufacture example of the polyester film in this invention is demonstrated concretely, it is not limited to the following manufacture examples at all.

  First, a method of using the polyester raw material described above and cooling and solidifying a molten sheet extruded from a die with a cooling roll to obtain an unstretched sheet is preferable. In this case, in order to improve the flatness of the sheet, it is necessary to improve the adhesion between the sheet and the rotary cooling drum, and an electrostatic application adhesion method and / or a liquid application adhesion method are preferably employed. Next, the obtained unstretched sheet is stretched in the biaxial direction. In that case, first, the unstretched sheet is stretched in one direction by a roll or a tenter type stretching machine. The stretching temperature is usually 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Subsequently, the extending | stretching temperature orthogonal to the 1st step | paragraph extending | stretching direction is 70-170 degreeC normally, and a draw ratio is 3.0-7 times normally, Preferably it is 3.5-6 times. Subsequently, heat treatment is performed at a temperature of 180 to 270 ° C. under tension or under relaxation within 30% to obtain a biaxially oriented film. In the above-described stretching, a method in which stretching in one direction is performed in two or more stages can be employed. In that case, it is preferable to carry out so that the draw ratios in the two directions finally fall within the above ranges.

  The simultaneous biaxial stretching method can also be adopted for the production of the polyester film in the present invention. The simultaneous biaxial stretching method is a method in which the unstretched sheet is usually stretched and oriented in the machine direction and the width direction at 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is as follows: The area magnification is 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times. Subsequently, heat treatment is performed at a temperature of 170 to 250 ° C. under tension or under relaxation within 30% to obtain a stretched oriented film. With respect to the simultaneous biaxial stretching apparatus that employs the above-described stretching method, conventionally known stretching methods such as a screw method, a pantograph method, and a linear drive method can be employed.

  Furthermore, a so-called coating stretching method (in-line coating) in which the film surface is treated during the above-described polyester film stretching step can be applied. When a coating layer is provided on a polyester film by a coating stretching method, coating can be performed simultaneously with stretching and the thickness of the coating layer can be reduced according to the stretching ratio, producing a film suitable as a polyester film. it can.

  The coating layer constituting the double-sided coating film in the present invention has good adhesion to the hard coat layer and, after forming a laminate, wet heat treatment under high temperature and high humidity (for example, 85 ° C., 85% RH) Even later, it is an essential requirement that the increase in film haze is as small as possible.

  It is preferable that the coating layer which comprises the polyester film laminated body of this invention has a coating layer formed from the coating liquid containing a 70 weight% or more crosslinking agent as a non-volatile component. The coating solution may contain other components as long as the gist of the present invention is not impaired.

  Various known crosslinking agents can be used as the crosslinking agent, and examples thereof include oxazoline compounds, melamine compounds, epoxy compounds, isocyanate compounds, carbodiimide compounds, and silane coupling compounds. Among these, especially when using for the use which provides a functional layer on a coating layer, an oxazoline compound is used suitably from a viewpoint that durable adhesiveness improves. Moreover, a melamine compound is used suitably from a viewpoint of prevention of precipitation of the ester cyclic trimer on the film surface by heating and improvement of durability and applicability of the coating layer.

  The oxazoline compound is a compound having an oxazoline group in the molecule, and a polymer containing an oxazoline group is particularly preferable, and can be prepared by polymerization of an addition polymerizable oxazoline group-containing monomer alone or with another monomer. Addition polymerizable oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, and the like can be mentioned, and one or a mixture of two or more thereof can be used. Among these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially. The other monomer is not limited as long as it is a monomer copolymerizable with an addition polymerizable oxazoline group-containing monomer. For example, alkyl (meth) acrylate (the alkyl group includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, (meth) acrylic acid esters such as n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group); acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, styrene Unsaturated carboxylic acids such as sulfonic acid and its salts (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); Unsaturated nitriles such as acrylonitrile, methacrylonitrile; (meth) acrylamide, N-alkyl ( (Meth) acrylamide, N, N-dialkyl (meth) acrylamide, As the alkyl group, unsaturated amides such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group and cyclohexyl group); vinyl acetate Vinyl esters such as vinyl propionate; vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; halogen-containing α, β-unsaturated monomers such as vinyl chloride, vinylidene chloride and vinyl fluoride And α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene, and the like, and one or more of these monomers can be used.

  The amount of the oxazoline group of the oxazoline compound contained in the coating solution forming the coating layer constituting the double-sided coating film in the present invention is usually 0.5 to 10 mmol / g, preferably 3 to 9 mmol / g, more preferably 5 It is in the range of ˜8 mmol / g. By using it in the above range, the durability of the coating film is improved.

  The melamine compound is a compound having a melamine structure in the compound, for example, an alkylolated melamine derivative, a compound partially or completely etherified by reacting an alcohol with an alkylolated melamine derivative, and these Mixtures can be used. As alcohol used for etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol and the like are preferably used. Moreover, as a melamine compound, either a monomer or a multimer more than a dimer may be sufficient, or a mixture thereof may be used. Further, a product obtained by co-condensing urea or the like with a part of melamine can be used, and a catalyst can be used to increase the reactivity of the melamine compound.

  The epoxy compound is a compound having an epoxy group in the molecule, and examples thereof include condensates of epichlorohydrin with ethylene glycol, polyethylene glycol, glycerin, polyglycerin, bisphenol A and the like hydroxyl groups and amino groups, There are polyepoxy compounds, diepoxy compounds, monoepoxy compounds, glycidylamine compounds, and the like. Examples of the polyepoxy compound include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, trimethylolpropane. Examples of the polyglycidyl ether and diepoxy compound include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and propylene glycol diglycidyl ether. , Polypropylene glycol diglycidyl ether, poly Examples of tetramethylene glycol diglycidyl ether and monoepoxy compounds include allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and glycidyl amine compounds such as N, N, N ′, N′-tetraglycidyl-m-xylyl. Examples include range amine and 1,3-bis (N, N-diglycidylamino) cyclohexane.

  The isocyanate compound is a compound having an isocyanate derivative structure typified by isocyanate or blocked isocyanate. Examples of isocyanate include aromatic isocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, and naphthalene diisocyanate, and aromatic rings such as α, α, α ′, α′-tetramethylxylylene diisocyanate. Aliphatic isocyanates such as aliphatic isocyanate, methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), isopropylidene dicyclohexyl diisocyanate Ne Alicyclic isocyanates such as bets are exemplified. Further, polymers and derivatives such as burettes, isocyanurates, uretdiones, and carbodiimide modified products of these isocyanates are also included. These may be used alone or in combination. Among the above isocyanates, aliphatic isocyanates or alicyclic isocyanates are more preferable than aromatic isocyanates in order to avoid yellowing due to ultraviolet rays.

  When used in the state of blocked isocyanate, the blocking agent includes, for example, bisulfites, phenolic compounds such as phenol, cresol, and ethylphenol, and alcohols such as propylene glycol monomethyl ether, ethylene glycol, benzyl alcohol, methanol, and ethanol. Compounds, active methylene compounds such as methyl isobutanoyl acetate, dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, acetylacetone, mercaptan compounds such as butyl mercaptan, dodecyl mercaptan, ε-caprolactam, δ-valerolactam, etc. Lactam compounds, amine compounds such as diphenylaniline, aniline, ethyleneimine, acetanilide, acid amide compounds of acetic acid amide, Examples include oxime compounds such as maldehyde, acetoald oxime, acetone oxime, methyl ethyl ketone oxime, and cyclohexanone oxime, and these may be used alone or in combination of two or more.

  In addition, the isocyanate compound in the present invention may be used alone, or may be used as a mixture or bond with various polymers. In the sense of improving the dispersibility and crosslinkability of the isocyanate compound, it is preferable to use a mixture or a bond with a polyester resin or a urethane resin.

  A carbodiimide-based compound is a compound having a carbodiimide structure, and is a compound having one or more carbodiimide structures in the molecule, but for better adhesion, etc., the polycarbodiimide having two or more in the molecule More preferred are system compounds.

  The carbodiimide compound can be synthesized by a conventionally known technique, and generally a condensation reaction of a diisocyanate compound is used. The diisocyanate compound is not particularly limited, and any of aromatic and aliphatic compounds can be used. Specifically, tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, hexa Examples include methylene diisocyanate, trimethylhexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl diisocyanate, and dicyclohexylmethane diisocyanate.

  The content of the carbodiimide group contained in the carbodiimide compound is a carbodiimide equivalent (weight of carbodiimide compound to give 1 mol of carbodiimide group [g]), and is usually 100 to 1000, preferably 250 to 700, more preferably 300. It is in the range of ~ 500. By using it in the above range, the durability of the coating film is improved.

  Furthermore, in order not to lose the effect of the present invention, in order to improve the water solubility and water dispersibility of the polycarbodiimide compound, adding a surfactant, polyalkylene oxide, quaternary ammonium salt of dialkylamino alcohol, You may add and use hydrophilic monomers, such as a hydroxyalkyl sulfonate.

These cross-linking agents may be used singly or in combination of two or more kinds, but by combining two or more kinds, adhesion to the functional layer, which has been difficult to be compatible, and oligomer after heating (ester cyclic trimer) ) Was improved. Among them, a combination of an oxazoline compound that can improve adhesion to a functional layer and a melamine compound that is excellent in preventing precipitation of an oligomer (ester cyclic trimer) after heating is optimal and preferable.
In addition, the present inventors have found that it is effective to combine three kinds of crosslinking agents in order to further improve the adhesion with the functional layer, and have completed the present invention. As a combination of three or more kinds of cross-linking agents, it is preferable to select a melamine compound as one of the cross-linking agents. As a cross-linking agent to be combined with the melamine compound, an oxazoline compound, an epoxy compound, and a carbodiimide type are used. Particularly preferred are compounds and epoxy compounds.

  When such a crosslinking agent is contained, a component for promoting crosslinking at the same time, for example, a crosslinking catalyst can be used in combination.

  In addition, in the formation of the coating layer of the present invention, the binder polymer is used within the range that does not impair the gist of the present invention in order to improve the coating appearance and the adhesion when the functional layer is formed on the coating layer. It is also possible to use together. The binder polymer constituting the coating layer in the present invention is a number average molecular weight measured by gel permeation chromatography (GPC) according to a polymer compound safety evaluation flow scheme (sponsored by the Chemical Substance Council in November 1985). It is defined as a polymer compound having (Mn) of 1000 or more and having a film-forming property.

  Specific examples of the polymer include polyester resin, acrylic resin, urethane resin, polyvinyl (polyvinyl alcohol, etc.), polyalkylene glycol, polyalkyleneimine, methylcellulose, hydroxycellulose, starches and the like. Among these, it is preferable to use a polyester resin, an acrylic resin, or a urethane resin from the viewpoint of improving adhesion with various surface functional layers. However, when the content increases, the precipitation prevention property of the ester cyclic trimer after heating may deteriorate, and it is usually 30% by weight or less, preferably 20% by weight or less, more preferably 10% by weight or less. When the ratio which occupies in a coating layer exceeds the said range, the precipitation inhibitory effect of the oligomer (ester cyclic trimer) after a heating may become inadequate.

  In addition, particles can be used in combination for the purpose of blocking and improving slipperiness in forming the coating layer. The average particle diameter is preferably 1.0 μm or less, more preferably 0.5 μm or less, and particularly preferably 0.2 μm or less from the viewpoint of transparency of the film. Further, the lower limit is preferably 0.01 μm or more, more preferably 0.03 μm or more, and particularly preferably a range larger than the film thickness of the coating layer in order to improve the slipperiness more effectively. Specific examples of the particles include silica, alumina, kaolin, calcium carbonate, and organic particles.

  Further, in the range not impairing the gist of the present invention, an antifoaming agent, a coating property improver, a thickener, an organic lubricant, an antistatic agent, an ultraviolet absorber, and an antioxidant are formed as necessary for forming the coating layer. It is also possible to use a foaming agent, a dye, a pigment and the like in combination.

  As a ratio with respect to all the non-volatile components in the coating liquid that forms the coating layer constituting the double-sided coating film in the present invention, the ratio of the crosslinking agent is preferably 70 wt% or more. More preferably, it is 80 weight% or more, Most preferably, it is 90 weight% or more. When the ratio of the crosslinking agent is less than 70% by weight, it may be difficult to suppress the precipitation of the oligomer (ester cyclic trimer) after heating the polyester film.

  From the viewpoint of preventing oligomer (ester cyclic trimer) precipitation after heat treatment, when melamine is selected as one of the crosslinking agents, the ratio of melamine as the ratio to the total nonvolatile components in the coating liquid forming the coating layer is: The range is usually from 5 to 95% by weight, preferably from 15 to 80% by weight, particularly preferably from 30 to 65% by weight. When the ratio of the crosslinking agent is out of the above range, precipitation suppression of the ester cyclic trimer after heating may be insufficient, or the coating appearance may be deteriorated.

  Further, the thickness (after drying) of the coating layer of the double-sided coating film is usually in the range of 0.003 μm to 1 μm, preferably 0.005 μm to 0.5 μm, more preferably 0.01 μm to 0.2 μm. It is a range. When the thickness is less than 0.003 μm, the amount of ester cyclic trimer precipitated from the film may not be sufficiently reduced. On the other hand, when the thickness is larger than 1 μm, there are cases where problems such as deterioration of the appearance of the coating layer and lowering of the blocking property may occur.

  Examples of methods for applying a coating solution to a polyester film include air doctor coating, blade coating, rod coating, bar coating, knife coating, squeeze coating, impregnation coating, reverse roll coating, transfer roll coating, gravure coating, and kiss roll coating. Conventional coating methods such as cast coating, spray coating, curtain coating, calendar coating, and extrusion coating can be used.

  In order to improve the coating property and adhesion of the coating agent to the film, the film may be subjected to chemical treatment, corona discharge treatment, plasma treatment or the like before coating.

  Analysis of various components in the coating layer can be performed by analysis of TOF-SIMS, ESCA, fluorescent X-rays, and the like.

  When providing a coating layer by in-line coating, the above-mentioned series of compounds is applied as an aqueous solution or dispersion, and the coating solution adjusted to a solid content concentration of about 0.1 to 50% by weight as a guide is applied onto the polyester film. It is preferable to produce a laminated polyester film. Moreover, in the range which does not impair the main point of this invention, a small amount of organic solvents may be contained in the coating liquid for the purpose of improving dispersibility in water, improving film-forming properties, and the like. Only one type of organic solvent may be used, or two or more types may be used as appropriate.

  In the present invention, the drying and curing conditions for forming the coating layer on the polyester film are not particularly limited. For example, when the coating layer is provided by off-line coating, it is usually 3 to 80 to 200 ° C. The heat treatment may be performed for 40 seconds, preferably 100 to 180 ° C. for 3 to 40 seconds.

  On the other hand, when the coating layer is provided by in-line coating, heat treatment is usually performed at 70 to 280 ° C. for 3 to 200 seconds as a guide.

  Further, irrespective of off-line coating or in-line coating, heat treatment and active energy ray irradiation such as ultraviolet irradiation may be used in combination as required. The polyester film constituting the laminated polyester film in the present invention may be subjected to surface treatment such as corona treatment or plasma treatment in advance.

  In the double-sided coated film of the present invention, when a surface functional layer such as a hard coat layer is provided on one of the coated layers to form a laminate, it has a hard coat layer on any exposed surface. . Although it does not specifically limit as a material used for a hard-coat layer, For example, hardened | cured materials, such as reactive silicon compounds, such as monofunctional (meth) acrylate, polyfunctional (meth) acrylate, and tetraethoxysilane, are mentioned. Among these, from the viewpoint of achieving both productivity and hardness, a polymerization cured product of a composition containing an ultraviolet curable polyfunctional (meth) acrylate is particularly preferable.

  It does not specifically limit as a composition containing a ultraviolet curable polyfunctional (meth) acrylate. For example, a mixture of one or more known ultraviolet curable polyfunctional (meth) acrylates, a commercially available UV curable hard coating agent, or other than these, in the range not impairing the purpose of the present embodiment, What added the other component further can be used.

  The UV-curable polyfunctional (meth) acrylate is not particularly limited. For example, dipentaerythritol hexa (meth) acrylate, tetramethylolmethanetetra (meth) acrylate, tetramethylolmethanetri (meth) acrylate, (Meth) acryl derivatives of polyfunctional alcohols such as trimethylolpropane tri (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,6-bis (3-acryloyloxy-2-hydroxypropyloxy) hexane And polyethylene glycol di (meth) acrylate and polyurethane (meth) acrylate.

  Other components contained in the composition containing an ultraviolet curable polyfunctional (meth) acrylate are not particularly limited. Examples thereof include inorganic or organic fine particles, polymerization initiators, polymerization inhibitors, antioxidants, antistatic agents, dispersants, surfactants, light stabilizers and leveling agents. Moreover, when making it dry after film forming in the wet-coating method, arbitrary amounts of solvents can be added.

  As a method for forming the hard coat layer, when an organic material is used, a general wet coat method such as a roll coat method or a die coat method is employed. The formed hard coat layer can be subjected to a curing reaction by heating, irradiation with active energy rays such as ultraviolet rays and electron beams as necessary.

  The coating thickness of the hard coat layer (after drying) needs to be in the range of 3 to 100 μm in consideration of scratch resistance, impact resistance, and flexibility. The range is preferably 5 to 90 μm, more preferably 10 to 80 μm. When the coating thickness (after drying) is less than 3 μm, the scratch resistance and impact resistance are insufficient. On the other hand, when it exceeds 100 μm, the flexibility becomes insufficient.

  Moreover, you may give surface treatments, such as a corona treatment and a plasma treatment, to a 1st double-sided coating film and a 2nd double-sided coating film previously.

  The film internal hazes of the first double-sided coated film and the second double-sided coated film thus obtained are preferably 0.6% or less, more preferably 0.4 when assuming substitute for glass, for example. % Or less. When the said range exceeds 0.6%, when light is permeate | transmitted through a polyester film laminated body, malfunctions, such as a poor visibility, will arise.

  In the present invention, regarding the first double-sided coated film and the second double-sided coated film, as a specific method for keeping the internal haze of the film to 0.6% or less, for example, in the first double-sided coated film, a laminated polyester film Is used, the particle content of the intermediate layer is suppressed to substantially 0%, and the particle content of the surface layer is increased with the polyester layer thickness being as thin as possible. It is preferable at the point from which the 1st double-sided coating film which has outstanding transparency is obtained.

  Next, the adhesive layer which comprises the laminated body of this invention is demonstrated below. The pressure-sensitive adhesive layer in the present invention means a layer composed of an adhesive material, and conventionally known materials can be used as long as the gist of the present invention is not impaired. As one specific example, the case where an acrylic adhesive is used will be described below.

  In the present invention, the acrylic pressure-sensitive adhesive means a pressure-sensitive adhesive layer containing, as a base polymer, an acrylic polymer formed using an acrylic monomer as an essential monomer component. The acrylic polymer has (meth) acrylic acid alkyl ester and / or (meth) acrylic acid alkoxyalkyl ester having a linear or branched alkyl group as an essential monomer component (more preferably as a main monomer component). ) It is preferably an acrylic polymer to be formed. Further, the acrylic polymer is particularly preferably an acrylic polymer formed using (meth) acrylic acid alkyl ester and acrylic acid alkoxyalkyl ester having a linear or branched alkyl group as essential monomer components. That is, the pressure-sensitive adhesive layer of the present invention is an acrylic pressure-sensitive adhesive layer formed using (meth) acrylic acid alkyl ester and acrylic acid alkoxyalkyl ester having a linear or branched alkyl group as essential monomer components. It is particularly preferred.

In addition, the monomer component forming the acrylic polymer that is the base polymer in the pressure-sensitive adhesive layer of the present invention further contains a polar group-containing monomer, a polyfunctional monomer, and other copolymerizable monomers. It may be contained as a polymerization monomer component.

In addition, said "(meth) acryl" represents "acryl" and / or "methacryl", and others are the same. Although not particularly limited, the content of the acrylic polymer as the base polymer in the pressure-sensitive adhesive layer of the present invention is 6% relative to the total weight (100% by weight) of the pressure-sensitive adhesive layer.
It is preferably 0% by weight or more, more preferably 80% by weight or more.

  As an essential monomer component for forming the acrylic polymer, a (meth) acrylic acid alkyl ester having a linear or branched alkyl group (hereinafter simply referred to as “(meth) acrylic acid alkyl ester”) may be used. ) Can be suitably used. Specific examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, (meth ) Isobutyl acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate , Octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, (meth) acrylic acid Isodecyl, undecyl (meth) acrylate, dodecyl (meth) acrylate, (Meth) acrylic acid tridecyl, (meth) acrylic acid tetradecyl, (meth) acrylic acid pentadecyl, (meth) acrylic acid hexadecyl, (meth) acrylic acid heptadecyl, (meth) acrylic acid octadecyl, (meth) acrylic acid nonadecyl, (meta ) (Meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group such as eicosyl acrylate. Moreover, the (meth) acrylic acid alkyl ester may be used alone or in combination of two or more. Among them, (meth) acrylic acid alkyl ester having 2 to 14 carbon atoms in the alkyl group is preferable, and (meth) acrylic acid alkyl ester having 2 to 10 carbon atoms in the alkyl group is more preferable. In particular, 2-ethylhexyl acrylate (2EHA) is preferable.

In addition, an essential monomer component for forming the acrylic polymer (more preferably,
As the main monomer component, (meth) acrylic acid alkoxyalkyl ester [alkoxyalkyl (meth) acrylate] can also be suitably used. Particularly preferably,
It is an acrylic acid alkoxyalkyl ester [alkoxyalkyl acrylate]. (
The (meth) acrylic acid alkoxyalkyl ester is not particularly limited.
(Meth) acrylic acid 2-methoxyethyl, (meth) acrylic acid 2-ethoxyethyl, (meth) acrylic acid methoxytriethylene glycol, (meth) acrylic acid 3-methoxypropyl, (meth) acrylic acid 3-ethoxypropyl, Examples include 4-methoxybutyl (meth) acrylate and 4-ethoxybutyl (meth) acrylate. The said (meth) acrylic-acid alkoxyalkylester can be used individually or in combination of 2 or more types. Among them, 2-methoxyethyl acrylate (2MEA) is preferable.

In addition, the content of the essential monomer component [(meth) acrylic acid alkyl ester and / or (meth) acrylic acid alkoxyalkyl ester] forming the above acrylic polymer is selected from the viewpoint of adhesiveness of the pressure-sensitive adhesive layer. The amount is preferably 5% by weight or more (for example, 5 to 100% by weight), more preferably 5 to 95% by weight, based on the total amount (100% by weight) of monomer components forming the polymer. In addition, when both (meth) acrylic acid alkyl ester and (meth) acrylic acid alkoxyalkyl ester are used as monomer components, the content of (meth) acrylic acid alkyl ester and (alkyl) alkoxyalkyl (meth) acrylate The total amount of ester content (total content) only needs to satisfy the above range.

  Among the above, it is preferable that both (meth) acrylic acid alkyl ester and acrylic acid alkoxyalkyl ester are used as essential monomer components for forming the acrylic polymer. In that case, the content of the (meth) acrylic acid alkyl ester is preferably 5 to 95% by weight, more preferably 10 to 90% by weight, based on the total amount of monomer components (100% by weight) forming the acrylic polymer. %, More preferably 65-80% by weight, most preferably 65-75% by weight. If the content exceeds 95% by weight, the adhesiveness may decrease, and if it is less than 5% by weight, the elastic modulus of the pressure-sensitive adhesive layer may be too high. Further, the content of the alkoxyalkyl ester of acrylic acid is preferably 10 to 45% by weight, more preferably 10 to 40% by weight, and still more preferably with respect to the total amount (100% by weight) of monomer components forming the acrylic polymer. 20 to 35% by weight. If the content exceeds 45% by weight, the elastic modulus of the pressure-sensitive adhesive layer may be too high, and if it is less than 10% by weight, the adhesiveness may decrease.

  Examples of the polar group-containing monomer include (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid and other carboxyl group-containing monomers or anhydrides thereof (maleic anhydride, etc. ); Hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl (meth) acrylate Hydroxyl group (hydroxyl group) -containing monomers such as vinyl alcohol and allyl alcohol; (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-hydro Amide group-containing monomers such as ethyl acrylamide; Amino group-containing monomers such as aminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, and t-butylaminoethyl (meth) acrylate; ) Glycidyl group-containing monomers such as glycidyl acrylate and methyl glycidyl (meth) acrylate; Cyano group-containing monomers such as acrylonitrile and methacrylonitrile; N-vinyl-2-pyrrolidone, (meth) acryloylmorpholine , N-vinyl pyridine, N-vinyl piperidone, N-vinyl pyrimidine, N-vinyl piperazine, N-vinyl pyrrole, N-vinyl imidazole, N-vinyl oxazole and other heterocyclic ring-containing vinyl monomers; sodium vinyl sulfonate, etc. Sulfonic acid group-containing monomer of 2-hydroxyethyl Chestnut phosphoric acid group-containing monomers such as acryloyl phosphate; cyclohexyl maleimide, imide group-containing monomers such as isopropyl maleimide; 2-methacryloyloxy such acryloyl isocyanate group-containing monomers such as methacryloyloxyethyl isocyanate. The said polar group containing monomer can be used individually or in combination of 2 or more types. Among the above-mentioned polar group-containing monomers, carboxyl group-containing monomers or acid anhydrides thereof, hydroxyl group-containing monomers, amino group-containing monomers, amide group-containing monomers, heterocyclic-containing vinyls Monomers are preferable, and acrylic acid (AA), 4-hydroxybutyl acrylate (4HBA), N-vinyl-2-pyrrolidone (NVP), and N-hydroxyethylacrylamide (HEAA) are particularly preferable.

  The content of the polar group-containing monomer is preferably 15% by weight or less with respect to 100% by weight of the monomer component forming the acrylic polymer. When it exceeds 15% by weight, the cohesive force of the pressure-sensitive adhesive layer becomes too high. As a result, the storage elastic modulus (23 ° C.) becomes too high, and the stress relaxation property may be lowered. If it is less than 0.01% by weight, the adhesion may be lowered.

  Among the above, the content of the hydroxyl group-containing monomer is preferably 5% by weight or less with respect to 100% by weight of the monomer component forming the acrylic polymer. When the content exceeds 5% by weight, the cohesive force of the pressure-sensitive adhesive layer becomes too high, the storage elastic modulus (23 ° C.) becomes too high, and the stress relaxation property may be lowered. Content of polar group-containing monomers other than hydroxyl group-containing monomers (particularly carboxyl group-containing monomers, amide group-containing monomers, amino group-containing monomers, heterocyclic-containing vinyl monomers) Is preferably 15% by weight or less with respect to 100% by weight of the monomer component forming the acrylic polymer. When the content exceeds 15% by weight, the cohesive force of the pressure-sensitive adhesive layer becomes too high, the storage elastic modulus (23 ° C.) becomes too high, and the stress relaxation property may be lowered.

Examples of the polyfunctional monomer include hexanediol di (meth) acrylate,
Butanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (Meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, Examples thereof include polyester acrylate and urethane acrylate. The said polyfunctional monomer can be used individually or in combination of 2 or more types. Among the above, as the polyfunctional monomer, trimethylolpropane triacrylate (TMPTA) is preferable.

  The content of the polyfunctional monomer is preferably 0.5% by weight or less with respect to 100% by weight of the total amount of monomer components forming the acrylic polymer. When the content exceeds 0.5% by weight, for example, the cohesive force of the pressure-sensitive adhesive layer becomes too high, and the stress relaxation property may be lowered.

  Examples of copolymerizable monomers (other copolymerizable monomers) other than the above polar group-containing monomers and polyfunctional monomers include cyclopentyl (meth) acrylate and cyclohexyl (meth). (Meth) acrylates having an alicyclic hydrocarbon group such as acrylate and isobornyl (meth) acrylate, and (meth) acrylates having an aromatic hydrocarbon group such as phenyl (meth) acrylate and the like (meth ) (Meth) acrylic acid esters other than alkyl acrylates, alkoxyalkyl (meth) acrylates, polar group-containing monomers and polyfunctional monomers; vinyl esters such as vinyl acetate and vinyl propionate; styrene , Aromatic vinyl compounds such as vinyl toluene; ethylene, butadiene, isoprene, isobutylene, etc. Olefins or dienes; vinyl ethers such as vinyl alkyl ethers; and vinyl chloride.

  The acrylic polymer can be prepared by polymerizing the above monomer components by a conventionally known or conventional polymerization method. Examples of the polymerization method of the acrylic polymer include a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, and a polymerization method by active energy ray irradiation (active energy ray polymerization method). Among them, the solution polymerization method and the active energy ray polymerization method are preferable in terms of transparency, water resistance, production cost and the like, and particularly when forming a relatively thick pressure-sensitive adhesive layer, active energy ray polymerization (photopolymerization and Method), and an ultraviolet polymerization method by ultraviolet irradiation is particularly preferable.

  Examples of the active energy rays irradiated in the above active energy ray polymerization (photopolymerization) include ionizing radiation such as α rays, β rays, γ rays, neutron rays, electron rays, and ultraviolet rays, among others. Ultraviolet rays are suitable for the use of the present invention. Further, the irradiation energy, irradiation time, irradiation method, and the like of the active energy ray are not particularly limited as long as they do not impair the gist of the present invention.

  In the solution polymerization, various common solvents can be used. Examples of such solvents include esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; cyclohexane and methylcyclohexane Organic solvents such as ketones such as methyl ethyl ketone and methyl isobutyl ketone. A solvent can be used individually or in combination of 2 or more types.

  In preparing the acrylic polymer, a polymerization initiator such as a thermal polymerization initiator or a photopolymerization initiator (photoinitiator) can be used depending on the type of polymerization reaction. A polymerization initiator can be used individually or in combination of 2 or more types.

  The photopolymerization initiator is not particularly limited. For example, benzoin ether photopolymerization initiator, acetophenone photopolymerization initiator, α-ketol photopolymerization initiator, aromatic sulfonyl chloride photopolymerization initiator, photo An active oxime photopolymerization initiator, a benzoin photopolymerization initiator, a benzyl photopolymerization initiator, a benzophenone photopolymerization initiator, a ketal photopolymerization initiator, a thioxanthone photopolymerization initiator, and the like can be used. The amount of the photopolymerization initiator used is not particularly limited, but is preferably in the range of 0.01 to 0.2 parts by weight with respect to 100 parts by weight of the total amount of monomer components forming the acrylic polymer.

  Specific examples of the benzoin ether photopolymerization initiator include, for example, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one. And anisole methyl ether. Examples of the acetophenone photopolymerization initiator include 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 4-phenoxydichloroacetophenone, and 4- (t-butyl). Examples include dichloroacetophenone. Examples of the α-ketol photopolymerization initiator include 2-methyl-2-hydroxypropiophenone and 1- [4- (2-hydroxyethyl) phenyl] -2-methylpropan-1-one. . Specific examples of the aromatic sulfonyl chloride photopolymerization initiator include 2-naphthalenesulfonyl chloride. Examples of the photoactive oxime photopolymerization initiator include 1-phenyl-1,1-propanedione-2- (o-ethoxycarbonyl) -oxime. Examples of the benzoin photopolymerization initiator include benzoin. Examples of the benzyl photopolymerization initiator include benzyl. Specific examples of the benzophenone photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3′-dimethyl-4-methoxybenzophenone, polyvinylbenzophenone, α-hydroxycyclohexyl phenyl ketone, and the like. Specific examples of the ketal photopolymerization initiator include benzyldimethyl ketal. Specific examples of the thioxanthone photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone, and the like.

  Specific examples of the thermal polymerization initiator include azo polymerization initiators [for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis-2-methylbutyronitrile, 2,2′-azobis. (2-methylpropionic acid) dimethyl, 4,4′-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [ 2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis (2-methylpropionamidine) disulfate, 2,2′-azobis (N, N′-di) Methyleneisobutylamidine) dihydrochloride], peroxide-based polymerization initiators (eg, dibenzoyl peroxide, tert-butylpermaleate, etc.), redox Scan type polymerization initiators and the like. The amount of the thermal polymerization initiator used is not particularly limited as long as it does not impair the gist of the present invention, and may be any range that can be conventionally used as a thermal polymerization initiator.

In the pressure-sensitive adhesive layer of the present invention, a cross-linking agent, a cross-linking accelerator, a tackifier (for example, rosin derivative resin, polyterpene resin, petroleum resin, oil-soluble phenol resin, etc.), anti-aging agent, filler, as necessary , Colorants (pigments, dyes, etc.), UV absorbers, antioxidants, chain transfer agents, plasticizers, softeners, surfactants, antistatic agents, etc., as necessary, as long as they do not impair the properties of the present invention. Can be used.

  The said crosslinking agent can control the gel fraction of an adhesive layer by bridge | crosslinking the base polymer of an adhesive layer. As crosslinking agents, isocyanate crosslinking agents, epoxy crosslinking agents, melamine crosslinking agents, peroxide crosslinking agents, urea crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents Agents, carbodiimide crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, amine crosslinking agents, and the like, and isocyanate crosslinking agents and epoxy crosslinking agents can be preferably used. A crosslinking agent can be used individually or in combination of 2 or more types.

  The pressure-sensitive adhesive layer thickness (after drying) of the polyester film laminate in the present invention is usually 25 to 200 μm, preferably 25 to 100 μm. When the thickness of the pressure-sensitive adhesive layer is 25 μm or less, it may be difficult to obtain a desired adhesive force. On the other hand, when the thickness of the pressure-sensitive adhesive layer exceeds 200 μm, curing of the pressure-sensitive adhesive layer becomes insufficient, and problems such as deterioration in workability may occur.

  For the laminate of the present invention, high transparency is required even after being exposed to a high temperature atmosphere for a long time, for example, for a touch panel. From this viewpoint, the total light transmittance of the polyester film laminate needs to be 90% or more. The total light transmittance is preferably 92% or more. When the total light transmittance of the laminate is less than 90%, the visibility becomes insufficient, and for example, it becomes difficult to apply to glass substitute applications.

  Furthermore, the film haze in the laminate is preferably 1.5% or less, more preferably 1.3% or less. If the film haze is less than 1.5%, for example, it may be difficult to apply to applications that require a high degree of visibility, such as glass replacement applications. In addition, in the polyester film laminate, the amount of change in film haze (ΔH) before and after wet-heat treatment for 100 hours in an atmosphere of 85 ° C. and 85% RH is 1.5% in consideration of application to electronic parts. Must be: ΔH is preferably 0.7% or less, and more preferably 0.3% or less.

  When ΔH exceeds 1.5%, the visibility decreases as the film haze rises due to the precipitation of the oligomer (ester cyclic trimer), and high visibility is required, for example, for touch panels. It becomes difficult to cope with optical applications.

  The film thickness of the polyester film laminate in the present invention is preferably in the range of 300 to 900 μm in consideration of impact resistance and handleability. More preferably, the range of 400-700 micrometers is good. When the film thickness is less than 300 μm, the impact resistance may be insufficient. On the other hand, when the film thickness exceeds 900 μm, problems such as deterioration in workability during handling may occur.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded. The measuring method used in the present invention is as follows.

(1) Measurement of intrinsic viscosity (dl / g) of polyester 1 g of polyester from which other polymer components and pigments incompatible with polyester have been removed are precisely weighed and mixed with phenol / tetrachloroethane = 50/50 (weight ratio). 100 ml of solvent was added and dissolved, and measurement was performed at 30 ° C.

(2) Average particle diameter (d50)
The average particle size d50 was defined as the particle size having an integrated volume fraction of 50% in an equivalent spherical distribution measured using a centrifugal sedimentation type particle size distribution analyzer (SA-CP3 type) manufactured by Shimadzu Corporation.

(3) Measurement of haze inside film of polyester film Using sample film, glass product filled with ethanol solution using haze meter device (model: HZ-2) manufactured by Suga Test Co., Ltd. based on JIS-K-7136. The haze value of the cell was set to 0%, and the haze value inside the film was measured in a state where the test piece of the sample film was immersed in the cell.

(4) Measurement of film haze The film haze of the measurement sample film (and laminate) was measured with a haze meter “HM-150” manufactured by Murakami Color Research Laboratory Co., Ltd. according to JIS-K-7136.

(5) Measurement of film haze change rate ΔH of polyester film laminate before and after wet heat treatment (practical property substitution evaluation)
In the sample film laminate, the film haze was measured by the method described in the item (4) after being left in a constant temperature and humidity chamber in an atmosphere of 85 ° C. and 85% RH for 100 hours (haze 1).
ΔH was calculated with a difference from the untreated film haze (haze 2) of the same sample.
ΔH = (haze 1) − (haze 2)
The lower ΔH, the less oligomer precipitation due to the wet heat treatment, which is better.
(Criteria)
A: ΔH is 0.3% or less. Especially good visibility.
○: ΔH exceeds 0.3% and is 0.7% or less. Good.
Δ: ΔH exceeds 0.7% and 1.5% or less. (Practical problems may occur.)
X: ΔH exceeds 1.5%. (Practical problem level)

(6) Evaluation of adhesion of hard coat layer Using the hard coat layer surface of the obtained laminate, 100 grid-shaped cuts were made using a cutter guide with a gap interval of 1 mm. Next, an 18 mm wide tape (Cello Tape (registered trademark) CT-18 manufactured by Nichiban Co., Ltd.) was applied to the cut surface on the grid, and the 2.0 kg roller was reciprocated 20 times to completely adhere to it. The peeled surface after peeling off rapidly at the peeling angle was observed and judged according to the following criteria.
(Criteria)
A: Peeling area is less than 5% B: Peeling area is 5% or more and less than 20% B: Peeling area is 20% or more and less than 50% X: Peeling area is 50% or more

(7) Foreign matter detection evaluation of polyester film laminate (practical property substitution evaluation)
In the production of each polyester film laminate of Examples and Comparative Examples, black metal powder (foreign matter) having a size of 50 μm or more was mixed at 50 / m 2 during the production of the pressure-sensitive adhesive composition, and the polyester film laminate was obtained. Produced. Next, from each of the first hard coat film side and the second hard coat film side of the obtained polyester film laminate, with a digital microscope (model: KH-7700) manufactured by HIROX being bonded together, The foreign substance was observed on the pressure-sensitive adhesive layer and judged according to the following criteria.
(Criteria)
○: The structure of the laminate allows inspection of foreign matter in the pressure-sensitive adhesive layer, making it easy to inspect (practically no problem level)
×: It is difficult to inspect the foreign material of the pressure-sensitive adhesive layer with a laminate structure (practically problematic level)
(8) Visibility evaluation after wet heat treatment of polyester film laminate (substitution evaluation of oligomer sealing property)
Regarding whether or not the adhesive layer can be observed in the laminated state after being left for 100 hours in an atmosphere of 85 ° C. and 85% RH in a thermostatic bath using each polyester film laminated body of Examples and Comparative Examples, The determination was made according to the following criteria.
(Criteria)
○: In the laminate structure, the adhesive layer can be inspected and easily inspected (practically practically satisfactory level)
×: Since the film haze is increased, it is difficult to inspect the adhesive layer with the laminate structure (practically problematic level)

(9) Evaluation of scratch resistance of hard coat layer surface of polyester film laminate (practical property substitution evaluation)
Taihei Rika Kogyo's exclusive jig (5cm x 7cm, 500g) is wrapped with sheet-like cotton (Bencot made by Asahi Kasei Co., Ltd.), and the hard coat layer surface of the first hard coat film and the second hard coat film is reciprocated 30 times (15cm length) Range). Thereafter, the rubbed portion was visually observed under a three-wavelength fluorescent lamp, and judged according to the following criteria.
(Criteria)
○: Scratch occurrence frequency is 3 or less ×: Scratch occurrence frequency exceeds 3 ○ ○ is a level that is not a problem in practical use

(10) Curling evaluation of polyester film laminate (practical property substitution evaluation)
The polyester film laminate is cut out so that each piece is a 10 cm square and used as a measurement sample, and then the sample is heat-treated in a hot air circulating furnace set at 150 ° C. for 60 minutes. Next, the sample was placed on a horizontal base, the heights of the four corners floating from the horizontal plane were measured, and this average value was taken as the curl value.
(Criteria)
○: Curl value is 3 mm or less (practically no problem level)
×: Curling value exceeds 3 mm (practically problematic level)
By performing the laminate planarity evaluation after the heat treatment based on the above determination, a more accurate film laminate can be obtained.

(11) UV absorption performance evaluation of polyester film laminate (practical property substitution evaluation)
Using a polyester film laminate, the light transmittance was continuously measured with a spectrophotometer (UV-3100PC type manufactured by Shimadzu Corporation) at a low scanning speed, a sampling pitch of 2 nm, and a wavelength of 300 to 700 nm. The light transmittance at a wavelength of 380 nm was measured.

(12) Flexibility evaluation of polyester film laminate (practical property substitution evaluation)
The polyester film laminate was evaluated by wrapping around a cylinder having a diameter of 80 mm, and after wrapping, the presence or absence of cracks or peeling of the hard coat layer was observed, and the determination was made according to the following criteria.
(Criteria)
○: There is no crack or peeling of the hard coat layer (a level that is practically acceptable)
X: Cracks and peeling of the hard coat layer are observed (practically problematic level)

(13) Impact resistance evaluation of polyester film laminate (practical property substitution evaluation)
Based on JIS K 5600-5-3, a DuPont impact tester equipped with a ¼ inch iron ball was used. A test film laminate was placed on a sample stage and a weight of 500 g was dropped from a height of 50 cm, and then the surface of the hard coat layer of the test piece was observed and judged according to the following criteria.
(Criteria)
○: Slight whitening is confirmed on the surface of the hard coat layer (a level with no problem in practical use)
Δ: A minute crack is confirmed on the surface of the hard coat layer (a level that may cause a problem in practical use)
X: Cracks are confirmed on the hard coat layer surface (practically problematic level)

(14) Comprehensive evaluation (practical property substitution evaluation)
Using polyester film laminates produced in Examples and Comparative Examples, each evaluation of visibility after wet heat treatment, foreign matter detection, hard coat adhesion, impact resistance, flexibility, curl properties, and scratch resistance Each item was comprehensively evaluated according to the following criteria.
(Criteria)
○: Visibility after wet heat treatment, foreign matter detection, hard coat adhesion, impact resistance, flexibility, curl properties, and scratch resistance are all ○ (a level that causes no problem in practical use)
Δ: At least one of visibility after wet heat treatment, foreign matter detection, hard coat adhesion, impact resistance, flexibility, curling property, and scratch resistance is Δ (a level that may cause a problem in practice) )
×: At least one of visibility after wet heat treatment, foreign matter detection property, hard coat adhesion, impact resistance, flexibility, curling property, and scratch resistance is × (a practically problematic level).
The polyester used in the examples and comparative examples was prepared as follows.
<Manufacture of polyester>

Production Example 1 (Polyester A1)
100 parts of dimethyl terephthalate, 60 parts of ethylene glycol and 0.09 part of magnesium acetate tetrahydrate are placed in a reactor, the temperature is raised by heating, methanol is distilled off, transesterification is performed, and 4 hours are required from the start of the reaction. The temperature was raised to 230 ° C. to substantially complete the transesterification reaction. Next, after adding 0.04 part of ethylene glycol slurry ethyl acid phosphate and 0.03 part of antimony trioxide, the temperature reached 280 ° C. and the pressure reached 15 mmHg in 100 minutes. It was 0.3 mmHg. After 4 hours, the system was returned to normal pressure to obtain polyester A1 having an intrinsic viscosity of 0.61 (dl / g).

Production Example 2 (Polyester A2)
In the method for producing polyester (A1), polyester (A1) was added except that after adding ethyl acid phosphate, silica particles having an average particle size of 2.3 μm were added so that the content with respect to polyester was 0.3% by weight. ) Was used to obtain polyester A2 having an intrinsic viscosity of 0.62 (dl / g).

Production Example 3 (Polyester A3)
Polyester (A1) is preliminarily crystallized at 160 ° C. and then solid-phase polymerized in a nitrogen atmosphere at a temperature of 210 ° C., and has an intrinsic viscosity of 0.72 (dl / g) and an ester cyclic trimer content. 0.50% by weight of polyester (A3) was obtained.

Production Example 4 (Polyester A4)
Produced in the same manner as in Production Example 3 except that silica particles having an average particle size of 2.3 μm were added to the polyester (A3) so that the content with respect to the polyester was 0.3% by weight, and the intrinsic viscosity was 0.72 ( dl / g) polyester (A4) was obtained.

Production Example 5 (Polyester A5)
Polyester (A1) was subjected to a twin screw extruder with a vent, and 2,2- (1,4-phenylene) bis [4H-3,1-benzoxazin-4-one] (manufactured by CY TEC Co., Ltd.) as an ultraviolet absorber. CYASORB UV-3638 (molecular weight 369 benzoxazinone type) was supplied to a concentration of 10% by weight and melt-kneaded to form chips, thereby producing an ultraviolet absorbent master batch polyester (A5). The intrinsic viscosity of the obtained polyester (A5) was 0.59 (dl / g).

Production Example 6 (Production of polyester film F1)
Polyester A3 and A4 are blended at a ratio of 90% and 10%, respectively, to the surface layer raw material, polyester A1 and A5 to 98%, and 2% raw material to the intermediate layer raw material and supplied to two vented extruders Then, after melt extrusion at 290 ° C., an amorphous film having a thickness of about 1500 μm was obtained by cooling and solidifying on a cooling roll having a surface temperature set to 40 ° C. using an electrostatic application adhesion method. This film was stretched 3.1 times in the machine direction at 85 ° C. Thereafter, a coating layer comprising the following coating solution was applied on both sides so that the coating thickness (after drying) was 0.04 g / m 2, the film was guided to a tenter, and stretched 3.8 times in the transverse direction at 110 ° C. Heat treatment was performed at 225 ° C. to obtain a polyester film F1 having a thickness of 250 μm (thickness ratio = 7 μm / 236 μm / 7 μm).

Moreover, the following was used as a composition contained in a coating liquid.
(A1): Hexamethoxymethylol melamine.
(A2): Epocros (made by Nippon Shokubai Co., Ltd.) which is an oxazoline compound. Oxazoline group amount 7.7 mmol / g.
(A3): Epocros (made by Nippon Shokubai Co., Ltd.) which is an oxazoline compound. Oxazoline group amount 4.5 mmol / g.
(A4): Polyglycerol polyglycidyl ether.

(A5): Block polyisocyanate synthesized by the following method.
1000 parts of hexamethylene diisocyanate was stirred at 60 ° C., and 0.1 part of tetramethylammonium capryate was added as a catalyst. After 4 hours, 0.2 part of phosphoric acid was added to stop the reaction, and an isocyanurate type polyisocyanate composition was obtained. 100 parts of the obtained isocyanurate type polyisocyanate composition, 42.3 parts of methoxypolyethylene glycol having a number average molecular weight of 400, and 29.5 parts of propylene glycol monomethyl ether acetate were charged and maintained at 80 ° C. for 7 hours. Thereafter, the reaction solution temperature was kept at 60 ° C., 35.8 parts of methyl isobutanoyl acetate, 32.2 parts of diethyl malonate, and 0.88 part of 28% methanol solution of sodium methoxide were added and kept for 4 hours. Block polyisocyanate obtained by adding 58.9 parts of n-butanol, maintaining the reaction solution temperature at 80 ° C. for 2 hours, and then adding 0.86 part of 2-ethylhexyl acid phosphate.
(A6): Carbodilite (manufactured by Nisshinbo Chemical Co., Ltd.), which is a polycarbodiimide compound. Carbodiimide equivalent 340.

(B1): Acrylic resin aqueous dispersion polymerized with the following composition and having a glass transition point of 40 ° C. Ethyl acrylate / n-butyl acrylate / methyl methacrylate / N-methylol acrylamide / acrylic acid = 65/21/10/2 / 2 (% by weight) emulsion polymer (emulsifier: anionic surfactant)
(B2): 315 parts by weight of terephthalic acid, 299 parts by weight of isophthalic acid, 74 parts by weight of ethylene glycol, and 265 parts by weight of diethylene glycol as the component (B2a), (B2a) 953 parts by weight, isophorone diisocyanate Polyester polyurethane comprising 267 parts by weight, ethylene glycol 56 parts by weight, and dimethylolpropionic acid 67 parts by weight neutralized with ammonia and dispersed in water (concentration 23%, viscosity at 25 ° C., 30 mPa · s) )

(C1): 2-amino-2-methylpropanol hydrochloride (F1) which is a melamine crosslinking catalyst: silica particles having an average particle diameter of 0.07 μm.

Production Example 7 (Production of Polyester Film F2) to Production Example 33 (Production of Polyester Film F28)
In Production Example 6, a polyester film was obtained in the same manner as in Production Example 6 except that the kind of polyester, the thickness, the blending ratio of raw materials, and the type of coating layer were different.

Example 1:
<Production of first double-sided coated film>
Polyester film F1 was used.
<Manufacture of second double-sided coated film>
Polyester film F1 was used.
<Production of first and second hard coat films>
On one coating layer of the polyester film F1, a hard coat layer composed of the following hard coat agent composition was applied and dried so that the coating thickness (after drying) was 30 μm to obtain a hard coat film.

<Composition for forming hard coat layer>
On one surface of the coating layer, a coating agent having the following coating composition was applied so that the thickness after curing was 10 μm, and dried in a hot air drying oven set at 80 ° C. for 1 minute. Next, using a high-pressure mercury lamp having an energy of 120 W / cm, curing was performed at 300 mJ / cm ² at an irradiation distance of 50 mm to obtain a hard coat film having an active energy ray-curable resin layer provided on the film.
<< Coating composition >>
Nippon Gohsei Kagaku Kogyo Co., Ltd. purple light 7650B and Ciba Specialty Chemicals Irgacure 651 were mixed at a weight ratio of 100/5 and diluted with methyl ethyl ketone to a concentration of 30% by weight.

<Manufacture of polyester film laminate>
The release film (light release) was peeled off from the coating layer surface of the obtained second hard coat film, and a pressure-sensitive adhesive sheet composed of the following acrylic pressure-sensitive adhesive composition was bonded thereto. Next, the release film (heavy release) was peeled off, and the coating layer surface of the first hard coat film was bonded to the exposed adhesive sheet surface to obtain a polyester film laminate.

In addition, the adhesive sheet to be used used what was previously stored with the structure shown in the optical transparent adhesive sheet (OCA: Optical Clear Adhesive) shown below. Specifically, a coating solution comprising the following pressure-sensitive adhesive layer forming composition is applied to the surface of the release layer of a heavy release type release film (Diafoil MRV75 (V08) manufactured by Mitsubishi Plastics), and then heat treated at 100 ° C. for 5 minutes. Thus, an adhesive layer having a coating amount (after drying) of 25 μm was obtained. Then, a light release type release film (Mitsubishi Resin Diafoil MRE38) is bonded to the exposed adhesive layer surface, and OCA is composed of release film (light release) / adhesive layer / release film (heavy release). Got.
<Acrylic pressure-sensitive adhesive layer forming composition>
(Monomer composition)
2-ethylhexyl acrylate 70% by weight
2-methoxyethyl acrylate 29% by weight
4-hydroxybutyl acrylate 1% by weight
0.1 part of Nippon Polyurethane Coronate L was added to 100 parts by weight of the monomer composition to obtain an acrylic pressure-sensitive adhesive layer forming composition.

Examples 2-25:
In Example 1, except that the coating liquid composition, the combination of the first polyester film and the second polyester film, and the coating thickness of the hard coat layer (after drying) were changed, the polyester film was laminated in the same manner as in Example 1. Got the body.

Comparative Example 1:
In Example 1, it manufactured like Example 1 except having changed the polyester film F1 into the polyester film F29 (a coating layer is not provided in both surfaces), and obtained the polyester film laminated body.

Comparative Example 2:
In Example 1, it manufactured similarly to Example 1 except having changed the application | coating thickness (after drying) of a hard-coat layer into 110 micrometers, and obtained the polyester film laminated body.

Comparative Example 3:
In Example 1, it manufactured like Example 1 except changing the application thickness (after drying) of a hard-coat layer into 1 micrometer, and obtained the polyester film laminated body.

Comparative Example 4:
In Example 1, it manufactured like Example 1 except providing a hard-coat layer only on one exposed coating layer, and obtained the polyester film laminated body. The obtained laminate was curled more largely in the curl evaluation, probably due to the asymmetric structure centered on the adhesive layer.

Comparative Example 5:
In Example 1, it manufactured like Example 1 except having changed the polyester film F1 into the polyester film F27, and obtained the polyester film laminated body. Since film crystallization progressed at the stage of forming the polyester film F27 and the film haze increased, the film was used as a constituent member, so that it was difficult to apply for glass replacement.

Comparative Examples 6-8:
In Example 1, it manufactured similarly to Example 1 except changing the kind of application layer, and obtained the polyester film laminated body.

Comparative Example 9:
In Example 1, it manufactured like Example 1 except having changed the polyester film F1 into the polyester film F28, and obtained the polyester film laminated body.

  The characteristic of each polyester film laminated body obtained by the said Example and comparative example is shown in Tables 1-6.

The present invention relates to a polyester film laminate, for example, for the purpose of glass replacement, and has a hard surface with high hardness having excellent scratch resistance and flexibility, and visibility after wet heat treatment, foreign matter detection, hard coat adhesion Provided is a polyester film laminate having good properties, impact resistance and curling properties.

DESCRIPTION OF SYMBOLS 10 Polyester film laminated body 11 Adhesive layer 31 1st hard coat film 13 Hard coat layer 14 Application layer 15 1st polyester film base material 16 Application layer 32 2nd hard coat film 22 Hard coat layer 23 Application layer 24 2nd polyester film Base material 25 Coating layer

Claims (2)

A laminate having a coating layer on both sides of a polyester film and having a thickness of 125 to 350 μm bonded to both sides of the pressure-sensitive adhesive layer, and a hard coat having a thickness (after drying) of 2 to 100 μm on both sides of the exposed coating layer The laminate has a total light transmittance of 90% or more, and the film haze change rate (ΔH) of the laminate before and after wet-heat treatment for 100 hours in an atmosphere of 85 ° C. and 85% RH is 1.5. % Laminate or less. The laminate according to claim 1, wherein the coating layer on the side bonded to the pressure-sensitive adhesive layer is formed from a coating solution containing 70% by weight or more of a crosslinking agent as a nonvolatile component.

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