JP2018069591A - Hard coat film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester film which hardly causes peeling and is hardly scratched during sticking even when stuck to a heat-resistant film.SOLUTION: A hard coat film is formed by layering an anchor layer and a hard coat layer in this order on at least one surface of a polyester film, where the hard coat layer is a layer formed by curing a curable resin having a polyfunctional acrylate compound containing at least two (meth)acryloyl groups in the molecule and an isocyanate compound as constitutional units and particles, and a coefficient of contraction Sin a travel direction (MD) of a film after heating at 150°C for 90 minutes is 0.05% to 0.25%, and a coefficient of contraction Sin a direction (TD) orthogonal to the travel direction of the film is -0.05% to 0.05%.SELECTED DRAWING: None

Description

  The present invention relates to a hard coat film that hardly peels even when laminated with a film having high heat resistance.

  Conventionally, polyester films have been used in various fields by taking advantage of mechanical properties, optical properties, dimensional stability, and the like. Examples thereof include touch panel products and flexible substrates. In particular, in the field of touch panels, ITO films are widely used as conductive films.

  However, with the recent increase in screen size of touch panels, there is a demand for lower resistance of ITO films. Generally, high temperature firing is required to reduce the resistance of an ITO film, and a heat resistant film is required. For this reason, the case where the further heat resistance is calculated | required by the polyester film has increased in recent years.

  Not only the ITO film but also high-temperature treatment that is not suitable for polyester film during the production of highly functional products such as patterning of a wiring board or forming an insulating film of organic EL as disclosed in JP-A-2006-9118 (Patent Document 1) The amount of processing is increasing year by year.

  In response to such demands, there are cases in which heat-resistant films other than polyester films, for example, films using polyimide or cycloolefin polymers are used.

  However, such films are generally more expensive than polyester films, which greatly increases the production cost of the final product. In order to reduce production costs, the film may be thinned. However, if the film is made thin, handling at the time of manufacturing the product becomes worse.

  As a method for solving these problems, there is a case in which a high temperature processing is performed using a heat resistant film, and then a polyester film is bonded together.

However, since there is a difference in shrinkage between the heat resistant film and the polyester film, there is a problem that peeling occurs when heat processing is performed after bonding.
In addition, there is a problem that the polyester film is damaged when bonded. In order to solve the above problems, a method of carrying out hard coating can be mentioned. However, since hard coating generally contracts, there is a problem that peeling occurs at the time of bonding due to curling accompanying the contraction.

Japanese Patent Laid-Open No. 2006-9118

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a polyester film that does not easily peel off even when bonded to a film having high heat resistance and is not easily damaged when bonded.

  As a result of intensive studies in view of the above circumstances, the present inventors have a hard coat layer containing an anchor layer, a specific compound and particles, and use a polyester film having a specific shrinkage rate as a constituent member. As a result, the present invention has been completed.

That is, the present invention is a hard coat film in which an anchor layer and a hard coat layer are laminated in this order on at least one surface of a polyester film, and the hard coat layer contains at least two (meth) acryloyl groups in the molecule. a layer obtained by curing a curable resin and particles having a polyfunctional acrylate compound and an isocyanate compound as a constituent unit, and the shrinkage factor S _MD of the running direction (MD) of after heating at 0.99 ° C. 90 min film 0 .05% to 0.25%, shrinkage _{S TD} in the direction perpendicular to the traveling direction of the film (TD) resides on the hard coat film, which is a -0.05% to 0.05%.

  According to the present invention, it is possible to provide a polyester film that hardly peels off even when bonded to a film having high heat resistance and is not easily damaged when bonded. Therefore, it is possible to solve the handling problem, which is a problem when a high-functional film requiring processing at a high temperature, such as a low-resistance conductive film or an organic EL resin substrate, is produced at low cost. Moreover, it is hard to produce a malfunction also at the time of subsequent processing, and its industrial value is very high.

Hereinafter, the present invention will be described in detail, but the present invention is not limited to the following description, and can be arbitrarily modified and implemented without departing from the gist of the present invention.
[1. Polyester film]
The polyester film in the present invention may have a single layer structure or a laminated structure, and may have a laminated structure of four layers or more as long as the gist of the present invention is not exceeded other than the two-layer or three-layer structure. There is no particular limitation.

  In the present invention, the polyester is obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol. 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. Typical polyesters include polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN) and the like.

  The polyester used in the present invention may be a homopolyester or a copolyester. In the case of a copolyester, a copolymer containing 30 mol% or less of the third component is preferred. Examples of the dicarboxylic acid component of the copolyester include one or more of isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, and sebacic acid. As the glycol component, One kind or two or more kinds of ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol and the like can be mentioned.

  When the polyester film used in the present invention undergoes a heating step before being bonded to the heat resistant film, oligomers are generated from the polyester film, which may contaminate the production process. Therefore, the amount of oligomer contained in the polyester film is preferably 0.7% by weight or less, and more preferably 0.5% by weight or less. When the amount of oligomer is more than 0.7% by weight, the production process may be contaminated.

  The polyester film used in the present invention may be a film having a structure in which a polyester having a low oligomer content is coextruded and laminated on at least one surface of a layer composed of a polyester having a normal oligomer content. When it has a structure, the effect of suppressing oligomer precipitation obtained in the present invention can be exhibited to a high degree.

  When the polyester film used in the present invention has a laminated structure, the average particle diameter is 0.1 to 0.6 μm in both outer layers, mainly for the purpose of imparting slipperiness and preventing scratches in each step. It is preferable to blend particles.

The particles to be blended are not particularly limited as long as they can impart slipperiness. Specific examples thereof include silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, and kaolin. And particles such as aluminum oxide and titanium oxide. 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 resin, thermosetting phenol resin, thermosetting epoxy resin, benzoguanamine resin, 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.

  Further, the particle content in both outer layers is usually 0.05 to 1.0% by weight, preferably 0.05 to 0.5% by weight. When the particle content is less than 0.05% by weight, the slipperiness of the film may be insufficient, and as a result, appearance defects such as scratches may occur during film processing. On the other hand, when adding more than 1.0% by weight of the particles, the film transparency may be insufficient.

  Furthermore, it is preferable to use aluminum oxide particles in the polyester layers of both outer layers constituting the polyester film used in the present invention for the purpose of preventing scratches or imparting slipperiness. When the average particle diameter of the aluminum oxide particles is out of the above range, the damage preventing effect or the slipperiness may be poor.

  Specific examples of the aluminum oxide particles used in the present invention include γ-type and δ-type aluminum oxide produced by flame hydrolysis using anhydrous aluminum chloride as a raw material.

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

  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 addition to the above-mentioned particles, conventionally known UV absorbers, antioxidants, antistatic agents, thermal stabilizers, lubricants, dyes, pigments, etc. may be added to the polyester film in the present invention as necessary. Can do.

  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.

That is, 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 preferable 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 is 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 7.0 times, preferably 3.0 to 6.0 times.
Next, the film is stretched in the direction perpendicular to the first stretching direction. In that case, the stretching temperature is usually 70 to 170 ° C., and the stretching ratio is usually 3.0 to 7.0 times, preferably 3.5 to 6 times. .0 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.

  In the present invention, the simultaneous biaxial stretching method can also be adopted for the production of the polyester film. 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 a temperature controlled usually at 70 to 120 ° C., preferably 80 to 110 ° C. 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 the anchor layer is provided on the polyester film by the coating stretching method, the anchor layer can be applied simultaneously with stretching and the thickness of the anchor layer can be reduced according to the stretching ratio. Can be manufactured.

  The thickness of the polyester film in the present invention is not particularly limited as long as it can be produced as a film, but it is usually 50 to 250 μm as a support for a thin heat-resistant film.

[2. Anchor layer]
In the polyester film of the present invention, it is important to use an anchor layer in order to improve adhesion with the hard coat layer. Further, surface treatment such as corona treatment or plasma treatment may be performed. Regarding the anchor layer, it may be provided by in-line coating which treats the film surface during the process of forming the polyester film, or offline coating which is applied outside the system on the once produced film may be adopted. Since the coating can be performed simultaneously with the film formation, the production can be handled at a low cost, and therefore in-line coating is preferably used.

  The in-line coating is not limited to the following, but for example, in the sequential biaxial stretching, it is preferable to perform the coating treatment before the transverse stretching in which the longitudinal stretching is finished. When the anchor layer is provided on the polyester film by in-line coating, the anchor layer can be applied simultaneously with film formation and the anchor layer can be processed at a high temperature, and the performance of the anchor layer can be improved by thermal crosslinking. A film suitable as a polyester film can be produced.

  In the present invention, it is preferable that one or more types of crosslinking agents are used in the anchor layer, and two or more types are more preferable. This is to improve adhesion to the hard coat layer and wet heat resistance on the anchor layer. Among them, by combining two or more kinds of crosslinking agents, it is possible to have adhesion and wet heat resistance that cannot be achieved by one kind of crosslinking agent. In addition, the crosslinking agent in an anchor layer forms a crosslinked structure in an anchor layer by reaction according to the chemical structure of the crosslinking agent. Although the reaction method of crosslinking is not limited, heating etc. are mentioned.

  Various known crosslinking agents can be used as the crosslinking agent, and examples thereof include isocyanate compounds, oxazoline compounds, melamine compounds, epoxy compounds, carbodiimide compounds, and their reaction products.

  The isocyanate compound is a compound derived from an isocyanate derivative typified by isocyanate or blocked isocyanate. Examples of the 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 Exemplified alicyclic isocyanates such as bets are tolylene diisocyanate and hexamethylene diisocyanate is particularly preferable from the viewpoint of adhesion among them. 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.

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 dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate and acetylacetone, mercaptan compounds such as butyl mercaptan and dodecyl mercaptan, lactam compounds such as ε-caprolactam and δ-valerolactam , Amine compounds such as diphenylaniline, aniline, ethyleneimine, acetanilide, acid amide compounds of acetic acid amide, formaldehyde, acetoald Examples include oxime compounds such as oxime, acetone oxime, methyl ethyl ketone oxime, and cyclohexanone oxime, and these may be used alone or in combination of two or more.
Moreover, the isocyanate compound mentioned above may be used alone, and may be used as a mixture or a combined product with various polymers.

  An oxazoline compound is a compound having an oxazoline group in the molecule. In particular, a polymer containing an oxazoline group is preferable, and it 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.

  A melamine compound is a compound having a melamine skeleton 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 a mixture thereof 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.

  As an epoxy compound, the compound containing an epoxy group in a molecule | numerator, its prepolymer, and hardened | cured material are mentioned, for example. Examples include condensates of epichlorohydrin with hydroxyl groups and amino groups such as ethylene glycol, polyethylene glycol, glycerin, polyglycerin, and bisphenol A, and polyepoxy compounds, diepoxy compounds, monoepoxy compounds, glycidylamine compounds, and the like. is there. 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, trimethylol. Examples of the propane 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, propylene glycol diglycidyl ether. Ether, polypropylene glycol diglycidyl ether, Ritetramethylene glycol diglycidyl ether and monoepoxy compounds include, for example, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and glycidyl amine compounds such as N, N, N ′, N′-tetraglycidyl-m- Examples include xylylenediamine and 1,3-bis (N, N-diglycidylamino) cyclohexane.

  Among these crosslinking agents, it is preferable to use an isocyanate compound or an oxazoline compound from the viewpoints of adhesion to the hard coat layer and heat and humidity resistance. Furthermore, when consideration is given to application to in-line coating, it is more preferable to have water solubility or water dispersibility.

  In the laminated polyester film of the present invention, a polymer is applied to the anchor layer for the purpose of improving the smoothness of the coated surface, reducing interference unevenness when the hard coat layer is laminated on the coated surface, and improving transparency and adhesion. It can also be used in combination.

  Specific examples of the polymer include a polyester resin not containing a naphthalene skeleton, an acrylic resin, a urethane resin, a polyalkylene glycol, a polyalkyleneimine, methylcellulose, hydroxycellulose, and starches. Among these, polyester resins, acrylic resins, and urethane resins that do not contain a naphthalene skeleton are preferable from the viewpoint of improving adhesion to a surface functional layer such as a hard coat layer.

  The acrylic resin is a polymer composed of a polymerizable monomer having a carbon-carbon double bond, as typified by acrylic and methacrylic monomers. These may be either a homopolymer or a copolymer. Moreover, the copolymer of these polymers and other polymers (for example, polyester, polyurethane, etc.) is also included. For example, a block copolymer or a graft copolymer. Alternatively, a polymer (possibly a mixture of polymers) obtained by polymerizing a polymerizable monomer having a carbon-carbon double bond in a polyester solution or a polyester dispersion is also included. Similarly, a polymer (in some cases, a mixture of polymers) obtained by polymerizing a polymerizable monomer having a carbon-carbon double bond in a polyurethane solution or polyurethane dispersion is also included. Similarly, a polymer obtained by polymerizing a polymerizable monomer having a carbon-carbon double bond in another polymer solution or dispersion (in some cases, a polymer mixture) is also included. Moreover, in order to improve adhesiveness, it is also possible to contain a hydroxyl group and an amino group.

  The polymerizable monomer having a carbon-carbon double bond is not particularly limited, but particularly representative compounds include, for example, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, citracone. Various carboxyl group-containing monomers such as acids, and salts thereof; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, monobutyl hydroxyl fumarate, Various hydroxyl group-containing monomers such as monobutylhydroxy itaconate; various monomers such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate ( (Meth) acrylic acid esters; Various nitrogen-containing compounds such as meth) acrylamide, diacetone acrylamide, N-methylol acrylamide or (meth) acrylonitrile; various styrene derivatives such as styrene, α-methylstyrene, divinylbenzene, vinyltoluene, vinyl propionate Various vinyl esters such as: Various silicon-containing polymerizable monomers such as γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, etc .; Phosphorus-containing vinyl monomers; Various such as vinyl chloride and biridene chloride And various conjugated dienes such as butadiene.

  The urethane resin is a polymer compound having a urethane bond in the molecule. Usually, urethane resin is prepared by reaction of polyol and isocyanate. Examples of the polyol include polycarbonate polyols, polyester polyols, polyether polyols, polyolefin polyols, and acrylic polyols. These compounds may be used alone or in combination.

  Polycarbonate polyols are obtained from a polyhydric alcohol and a carbonate compound by a dealcoholization reaction. Examples of the polyhydric alcohols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentane. Diol, 1,6-hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decane Diol, neopentyl glycol, 3-methyl-1,5-pentanediol, 3,3-dimethylol heptane and the like can be mentioned. Examples of the carbonate compound include dimethyl carbonate, diethyl carbonate, diphenyl carbonate, and ethylene carbonate. Examples of polycarbonate polyols obtained from these reactions include poly (1,6-hexylene) carbonate, poly (3- And methyl-1,5-pentylene) carbonate.

  Polyester polyols include polycarboxylic acids (malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, etc.) or their acid anhydrides. Product and polyhydric alcohol (ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol 2-methyl-2-propyl-1 3-propanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol 1,9-nonanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2-hexyl-1,3-propanediol, cyclohexane Diol, bishydroxymethylcyclohexane, dimethanolbenzene, bishydroxyethoxybenzene, alkyl dialkanolamine, lactone diol, etc.).

  Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polyethylene propylene glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, and the like.

  Examples of the polyisocyanate compound used for obtaining the urethane resin include aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, and tolidine diisocyanate, α, α, α ′, α ′. -Aliphatic diisocyanates having aromatic rings such as tetramethylxylylene diisocyanate, aliphatic diisocyanates such as methylene diisocyanate, propylene diisocyanate, trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl Methanzi Cyanate, alicyclic diisocyanates such as isopropylidene dicyclohexyl diisocyanates. These may be used alone or in combination.

  A chain extender may be used when synthesizing the urethane resin, and the chain extender is not particularly limited as long as it has two or more active groups that react with an isocyanate group. Alternatively, a chain extender having two amino groups can be mainly used.

  Examples of the chain extender having two hydroxyl groups include aliphatic glycols such as ethylene glycol, propylene glycol and butanediol, aromatic glycols such as xylylene glycol and bishydroxyethoxybenzene, and esters such as neopentyl glycol hydroxypivalate. And glycols such as glycols. Examples of the chain extender having two amino groups include aromatic diamines such as tolylenediamine, xylylenediamine, and diphenylmethanediamine, ethylenediamine, propylenediamine, hexanediamine, 2,2-dimethyl-1,3- Propanediamine, 2-methyl-1,5-pentanediamine, trimethylhexanediamine, 2-butyl-2-ethyl-1,5-pentanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10- Aliphatic diamines such as decane diamine, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, dicyclohexylmethanediamine, isoprobilitincyclohexyl-4,4′-diamine, 1,4-diaminocyclohexane, 1 , 3-Bisaminomethylcyclohexa And alicyclic diamines such as

  The urethane resin may use a solvent as a medium, but preferably uses water as a medium. In order to disperse or dissolve the urethane resin in water, there are a forced emulsification type using an emulsifier, a self-emulsification type in which a hydrophilic group is introduced into the urethane resin, and a water-soluble type. In particular, a self-emulsification type in which an ionic group is introduced into a skeleton of a urethane resin to form an ionomer is preferable because of excellent storage stability of the liquid and water resistance, transparency, and adhesion of the resulting anchor layer. Examples of the ionic group to be introduced include various groups such as a carboxyl group, sulfonic acid, phosphoric acid, phosphonic acid, and quaternary ammonium salt, and a carboxyl group is preferred. As a method for introducing a carboxyl group into a urethane resin, various methods can be taken in each stage of the polymerization reaction. For example, there are a method of using a carboxyl group-containing resin as a copolymer component during prepolymer synthesis, and a method of using a component having a carboxyl group as one component such as polyol, polyisocyanate, and chain extender. In particular, a method in which a desired amount of carboxyl groups is introduced using a carboxyl group-containing diol depending on the amount of this component charged is preferred. For example, dimethylolpropionic acid, dimethylolbutanoic acid, bis- (2-hydroxyethyl) propionic acid, bis- (2-hydroxyethyl) butanoic acid and the like are copolymerized with a diol used for polymerization of a urethane resin. Can do. The carboxyl group is preferably in the form of a salt neutralized with ammonia, amine, alkali metal, inorganic alkali or the like. Particularly preferred are ammonia, trimethylamine and triethylamine. In such a polyurethane resin, a carboxyl group from which the neutralizing agent has been removed in the drying step after coating can be used as a crosslinking reaction point by another crosslinking agent. Thereby, it is possible to further improve the durability, solvent resistance, water resistance, blocking resistance, and the like of the anchor layer obtained in addition to excellent stability in a liquid state before coating.

In the present invention, the anchor layer preferably contains particles for the purpose of improving the anchoring property and slipping property of the anchor layer. Specific examples of the particles include silica, alumina, kaolin, calcium carbonate, and organic particles, and silica is particularly preferable from the viewpoint of dispersibility.
The average particle diameter of the particles contained in the anchor layer is preferably 1.0 μm or less, more preferably 0.05 to 0.7 μm, particularly preferably 0.1 to 0.5 μm, from the viewpoint of film transparency. It is.

  Furthermore, as long as it does not impair the gist of the present invention, the anchor layer is formed as necessary with an antifoaming agent, a coating property improving agent, a thickener, an organic lubricant, an antistatic agent, an ultraviolet absorber, and an antioxidant. It is also possible to use a foaming agent, a dye, a pigment and the like in combination.

  The anchor layer thickness is usually 0.003 μm to 1 μm, preferably 0.005 μm to 0.5 μm, more preferably 0.01 μm to 0.2 μm, as the anchor layer thickness on the finally obtained film. is there. By setting the thickness to 0.003 μm or more, the oligomer (ester cyclic trimer) content precipitated from the film can be sufficiently suppressed. Moreover, the external appearance of an anchor layer becomes favorable by setting it as 1 micrometer or less, and there exists effects, such as sufficient blocking suppression.

As a method of applying a coating solution as an anchor layer to a polyester film, for example, air doctor coat, blade coat, rod coat, bar coat, knife coat, squeeze coat, impregnation coat, reverse roll coat, transfer roll coat, gravure coat, Conventionally known coating methods such as kiss roll coating, cast coating, spray coating, curtain coating, calendar coating, and extrusion coating can be used.
Moreover, in order to improve the applicability | paintability to the film of a coating liquid, and adhesiveness, you may give a chemical process, a corona discharge process, a plasma process, etc. to a film before application | coating.

[3. Hard coat layer]
It is important that the hard coat film of the present invention has a hard coat layer on an anchor layer on at least one side of the above-described polyester film. By having such a hard coat layer, scratches on the surface of the transparent substrate can be suppressed. In the present invention, the “hard coat layer” refers to a layer having less than 10 scratches after 10 round trips of the hard coat layer with # 0000 steel wool applied with a load of 100 g.

  The thickness of the hard coat layer in the present invention is preferably 0.1 to 10 μm, and more preferably 0.5 μm to 8 μm. When the thickness of the hard coat layer is less than 0.1 μm, the hard coat film tends to be insufficiently cured. When the thickness exceeds 10 μm, the hard coat layer shrinks and the film tends to curl when the heating process is performed. Tend.

  In the present invention, the coefficient of dynamic friction between the hard coat layer surface and the opposite surface is preferably 0.7 or less, more preferably 0.6 or less, in order to improve the winding property. By setting the dynamic friction coefficient to 0.7 or less, sufficient winding property can be ensured.

  In the present invention, the hard coat layer preferably has a refractive index of 1.40 to 1.48. By satisfying the range in which the refractive index is defined, the occurrence of blocking is sufficiently suppressed, which is preferable in production. The refractive index of the hard coat layer can be adjusted by adjusting the type or content of the particles.

  The hard coat layer is formed of a curable resin such as a thermosetting resin or a radiation curable resin as a main component. In the present invention, a radiation curable resin is preferable from the viewpoint of the hardness of the hard coat layer and a flatness of the obtained hard coat film, and an ultraviolet curable resin is particularly preferable. The hard coat layer in the present invention is preferably made of the following radiation curable resin as a main component. Here, “as a main component” means that it is 20% by weight or more, preferably 25% by weight or more based on the weight of the hard coat layer.

  A radiation curable resin is a monomer, oligomer, or polymer that can be crosslinked and cured by radiation. In the present invention, a curable resin containing as an essential component a polyfunctional (meth) acrylate containing at least two (meth) acryloyl groups in the molecule and an isocyanate compound is used.

  Such a polyfunctional (meth) acrylate is a compound containing an acryloyl group in the molecule, but by containing at least two (meth) acryloyl groups in the molecule, the crosslinking reaction of the radiation curable resin easily proceeds. Thus, the effect of improving the surface hardness can be increased. In addition, the polyfunctional (meth) acrylate compound in this invention may contain other polymerizable functional groups other than a (meth) acryloyl group in a molecule | numerator. Here, the “(meth) acryloyl group” represents an acryloyl group and / or a methacryloyl group. As the polyfunctional acrylate compound containing two (meth) acryloyl groups, a compound having a dipentaerythritol structure is particularly preferable.

  Specific examples of the polyfunctional acrylate compound containing at least two (meth) acryloyl groups in the molecule include, for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, butanediol di (meth) acrylate, hexane Diol di (meth) acrylate, nonanediol di (meth) acrylate, ethoxylated hexanediol di (meth) acrylate, propoxylated hexanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, Tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethoxylated neopentyl Bifunctional (meth) acrylates such as cold di (meth) acrylate, tripropylene glycol di (meth) acrylate, and hydroxypivalate neopentyl glycol di (meth) acrylate; trimethylolpropane tri (meth) acrylate, ethoxylated trimethylolpropane tri (Meth) acrylate, propoxylated trimethylolpropane tri (meth) acrylate, tris 2-hydroxyethyl isocyanurate tri (meth) acrylate, glycerin tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) ) Acrylate, ditrimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tet (Meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, ditrimethylolpropane penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ditrimethylolpropane hexa (meth) acrylate, etc. A polyfunctional (meth) acrylate having three or more functional groups; a modified product of a polyfunctional (meth) acrylate compound in which a part of these (meth) acrylates is substituted with an alkyl group or the like; a polyfunctional (meth) acrylate having an isocyanurate structure Polyfunctional (meth) acrylates having a nitrogen atom-containing heterocyclic structure such as: urethane (meth) acrylates having a hydroxyl group (meth) acrylate added to diisocyanate or triisocyanate, isocyanate compounds Examples include urethane (meth) acrylates such as urethane (meth) acrylate obtained by adding a (meth) acrylate having a hydroxyl group to a reaction product having an isocyanate group at the terminal obtained by reacting a product with a diol compound. These can be used alone or in combination of two or more.

In the present invention, it is important to use an isocyanate compound as an oligomer component in the polyfunctional acrylate compound. By using an isocyanate compound, a urethane bond can be formed and the flexibility of the hard coat layer can be increased.
Representative examples of isocyanate compounds include hexamethylene diisocyanate (HDI), 4,4′-methylenebiscyclohexyl isocyanate, isophorone diisocyanate, trimethylhexamethylene diisocyanate, 1,3- (isocyanatomethyl) cyclohexane, norbornene diisocyanate, and burettes thereof. Polymers such as compound, nurate and adduct can be mentioned. These can be used alone or in combination. Particularly preferred are hexamethylene diisocyanate, isophorone diisocyanate, 4,4′-methylenebiscyclohexyl isocyanate, and their uretrates.

  The number of repeating units of the polyfunctional (meth) acryl oligomer / polymer is not particularly limited. For example, the number average molecular weight is preferably 150 to 1,000,000, preferably 1,000 to 500,000, and the effect of improving the coating appearance is enhanced. Can do. When the number average molecular weight is less than 150, the viscosity tends to be too low. When the number average molecular weight exceeds 1000000, the viscosity tends to be too high. In each case, the effect of improving the coating appearance tends to be low. It is in.

[particle]
The hard coat layer contains particles in order to improve winding properties. The form of such particles is not particularly limited as long as the desired effect can be obtained, and may be organic particles or inorganic particles. Examples of the organic particles include organic polymer particles such as core-shell particles obtained by surface-treating silicone resin, crosslinked acrylic resin, crosslinked polyester, crosslinked polystyrene, and styrene resin with acrylic. Examples of inorganic particles include spherical silica particles, alumina particles, calcium carbonate particles, and the like.

  Moreover, when the average particle diameter of the particles is 0.01 μm or more and 1 μm or less, the handling property is excellent and the transparency is more easily maintained. From this viewpoint, the average particle size is more preferably 0.5 μm or less, and particularly preferably 0.4 μm or less.

  The content of the particles in the hard coat layer is preferably 0.1% by weight or more and 80% by weight or less based on the weight of the hard coat layer. By setting the content of the particles in the hard coat layer in the above range, the handling property is excellent and the transparency is more easily maintained. From this viewpoint, the content is more preferably 1% by weight or more, and particularly preferably 5% by weight or more.

(Radical polymerization initiator)
The curable resin constituting the hard coat layer is preferably cured by a radical polymerization initiator. Examples of the radical polymerization initiator include a compound that generates active radical species by radiation (light) irradiation (radiation (light) polymerization initiator), a compound that thermally generates active radical species (thermal polymerization initiator), and the like. Can be mentioned. If necessary, a radiation (light) polymerization initiator and a thermal polymerization initiator can be used in combination.

  The radiation (photo) polymerization initiator is not particularly limited as long as it can be decomposed by light irradiation to generate radicals to initiate polymerization. For example, acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2 , 2-dimethoxy-1,2-diphenylethane-1-one, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone, benzoin propyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy Roxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propane -1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 2 , 4,6-trimethylbenzoyldiphenylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) and the like.

  As a commercial item of a radiation (photo) polymerization initiator, for example, Ciba Specialty Chemicals Co., Ltd. trade name: Irgacure 127, 184, 369, 651, 500, 819, 907, 784, 2959, CGI 1700, CGI 1750, CGI1850, CG24-61, Darocur 1116, 1173; BASF Corporation product name: Lucirin TPO; UCB company product name: Ubekrill P36; , KIP75 / B and the like.

  Examples of the thermal polymerization initiator include peroxides and azo compounds. Specific examples include benzoyl peroxide, t-butyl-peroxybenzoate, and azobisisobutyronitrile. .

  The amount of the radical polymerization initiator used in the curable resin is preferably 0.01% by weight or more and 10% by weight or less, more preferably 0.1% by weight or more and 5% by weight or less, based on the weight of the hard coat layer. . If it is less than 0.01% by weight, the hardness may be insufficient, and if it exceeds 10% by weight, the inside may not be sufficiently cured.

(Other polymerizable compounds)
The curable resin may contain other polymerizable compounds. Examples of the polymerizable compound include vinyl compounds.

  Examples of the vinyl compounds include divinylbenzene, ethylene glycol divinyl ether, diethylene glycol divinyl ether, and triethylene glycol divinyl ether.

(Other polymerizable compounds)
The curable resin may contain other polymerizable compounds. Examples of the polymerizable compound include vinyl compounds.

  Examples of the vinyl compounds include divinylbenzene, ethylene glycol divinyl ether, diethylene glycol divinyl ether, and triethylene glycol divinyl ether.

(Other additives)
The curable resin may further contain other additives. Examples of the additive include an antistatic agent, a leveling agent, an ultraviolet absorber, an antioxidant, a light stabilizer, a pigment, a dye, a filling agent (excluding the above particles), a dispersant, a plasticizer, a surfactant, Examples include thixotropic agents.

  As the leveling agent, it is preferable to appropriately select and use a silicone-based or fluorine-based leveling agent. Examples of the silicone leveling agent include polydimethylsiloxane, polymethylalkylsiloxane, polyether-modified polydimethylsiloxane, polysiloxane having a (meth) acryl group, and the like.

  Examples of the ultraviolet absorber include benzotriazole-based, benzophenone-based, salicylic acid-based, and cyanoacrylate-based ultraviolet absorbers.

  Examples of the antioxidant include hindered phenol-based, sulfur-based, and phosphorus-based antioxidants.

  Examples of the light stabilizer include hindered amine light stabilizers.

  These other additives may be used alone or in combination of two or more. Moreover, as content of these other additives, 10 weight% or less is preferable in a hard-coat layer, and 3 weight% or less is more preferable.

(solvent)
The curable resin is usually used by diluting with a solvent in order to adjust the viscosity (coating property) or the thickness of the hard coat layer. The viscosity of the solution obtained by diluting the curable resin with a solvent is preferably 0.1 to 50,000 mPa · sec / 25 ° C., more preferably 0.5 to 10,000 mPa · sec / 25 ° C.

  Examples of the solvent include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone and cyclohexanone; esters such as ethyl acetate and butyl acetate; alcohols such as isopropyl alcohol and ethyl alcohol; benzene, toluene, xylene and methoxy Aromatic hydrocarbons such as benzene and 1,2-dimethoxybenzene; phenols such as phenol and parachlorophenol; halogenated hydrocarbons such as chloroform, dichloromethane, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene, and chlorobenzene can give. These solvents can be used alone or in combination of two or more.

  The solid content of the solution is preferably 70% by weight or less, more preferably 20% by weight or more or 60% by weight or less.

  The hard coat film of the present invention may require a high degree of transparency even after being exposed to a high temperature atmosphere for a long time, such as a member for a touch panel. From this viewpoint, in order to use as a member for a touch panel, the haze change rate (ΔH) before and after heat treatment (150 ° C., 90 minutes) is preferably 0.5% or less, more preferably 0.3% or less. However, 0.1% or less is most preferable. When ΔH exceeds 0.5%, the visibility decreases with an increase in haze, and may be inappropriate for applications that require high visibility, such as a touch panel member. Moreover, it shows that there is little precipitation of an oligomer, so that (DELTA) H is low.

In the present invention, the shrinkage factor _{S MD} in the running direction of after heating at 0.99 ° C. 90 minutes film (MD) is 0.05% to 0.25%, preferably 0.23% or less, more preferably 0. 20% or less.
If the shrinkage percentage _SMD is greater than 0.25%, the shrinkage difference between the bonded heat resistant films becomes large, and peeling occurs when processing is performed for a long time in a high temperature environment. On the other hand, when the shrinkage ratio _SMD is less than 0.05%, the shrinkage ratio is smaller than that of the heat resistant film, so that the curl direction after processing is reversed and a defect occurs.

In the present invention, the shrinkage ratio S _{TD in the} direction orthogonal to the running direction (TD) of the film after heating at 150 ° C. for 90 minutes is −0.05% to 0.05%, preferably −0.04% to It is 0.04%, more preferably -0.03% to 0.03%.
When departing from the scope of the shrinkage factor S _TD is defined, there is a possibility that the width change upon bonding the heat-resistant film would be made to occur a problem greatly.

In the present invention, annealing treatment is preferably performed in order to satisfy the shrinkage rates S _MD and S _TD . With respect to the annealing treatment, conventionally known methods can be employed. Specifically, the annealing temperature is preferably 160 to 200 ° C, more preferably 165 to 195 ° C, and still more preferably 170 to 190 ° C.
The annealing time is preferably 1 to 30 seconds, more preferably 3 to 20 seconds, and further preferably 5 to 15 seconds. Furthermore, the film tension (in the oven) is preferably 1 to 10 kg / m, more preferably 1 to 7 kg / m, and further preferably 1 to 5 kg / m. Moreover, it is preferable to anneal-treat, conveying a film at a film travel speed of 10-300 m / min.

  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. In the examples and comparative examples, “parts” means “parts by weight”. The measurement method and evaluation method used in the present invention are as follows.

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

(2) Oligomer (ester cyclic trimer) content of polyester raw material About 200 mg of polyester raw material was weighed and dissolved in 2 ml of a mixed solvent of chloroform / HFIP (hexafluoroisopropanol) in a volume ratio of 3: 2. After dissolution, 20 ml of chloroform was added, and 10 ml of methanol was added little by little. The precipitate was removed by filtration, and the precipitate was further washed with a mixed solvent having a chloroform / methanol volume ratio of 2: 1. The filtrate / washing solution was collected, concentrated by an evaporator, and then dried. After the dried product was dissolved in 25 ml of DMF (dimethylformamide), this solution was supplied to liquid chromatography (manufactured by Shimadzu Corporation: LC-7A) to determine the amount of oligomer in DMF, and this value was obtained as a chloroform / HFIP mixed solvent. It was divided by the weight of the polyester raw material dissolved in to give the oligomer content (% by weight). The oligomer content in DMF was determined from the peak area ratio between the standard sample peak area and the measured sample peak area (absolute calibration curve method).

(3) Average particle diameter (d50) and particle size distribution The particle size was measured by a sedimentation method based on Stokes' resistance law using a centrifugal sedimentation particle size distribution analyzer SA-CP3 (manufactured by Shimadzu Corporation), and the average The particle size and particle size distribution were determined.

(4) Film thickness, hard coat layer thickness After a laminated polyester film piece is fixed and molded with an epoxy resin, it is cut with a microtome, and a cross section of the laminated polyester film is observed with a transmission electron microscope (JEM 2010, manufactured by JEOL Ltd.). did. Two of the cross-sections are observed in parallel with the surface of the laminated polyester film, and the interface is observed by light and dark. The distance between the two interfaces and the laminated polyester film surface was measured from 15 photographs, and the average value of 9 points excluding 3 points from the larger value and 3 points from the smaller value, the film thickness, The hard coat layer thickness was used.

(5) Anchor layer thickness A laminated polyester film was fixed with an embedding resin, a cross section was cut with a microtome, and a sample was prepared by staining with 2% osmic acid at 60 ° C. for 2 hours. The obtained sample was observed with a transmission electron microscope (JEM2010 manufactured by JEOL Ltd.), and the thickness of the anchor layer was measured. A total of 15 films were measured, and the average of 9 points excluding 3 points from the larger value and 3 points from the smaller value was taken as the anchor layer thickness.

(6) Hard coat layer refractive index The refractive index was calculated using an Abbe refractometer (manufactured by Atago Optical Co., Ltd.). The refractive index was measured at 23 ° C. using sodium D line.

(7) Measurement of shrinkage rate (S _MD , S _TD ) About each shrinkage rate of MD and TD of the sample film, the sample film was heat-treated in an oven maintained at 150 ° C. in a non-tension state for 90 minutes. The length of the sample film was measured, and the shrinkage rate was calculated by the following formula.
Shrinkage rate = [{(length before heat treatment) − (length after heat treatment)} / (length before heat treatment)] × 100

(8) Haze (H ₀ )
Under a room temperature environment, haze H ₀ was measured for the sample film according to “HM-150” manufactured by Murakami Color Research Laboratory in accordance with JIS K7136.

(9) Haze after heat treatment (H ₁ )
After the sample film was processed under predetermined heat treatment conditions (150 ° C., 90 minutes), haze H ₁ was measured in the same manner as in the section (5).

(10) Haze change (ΔH)
From the measured values in the items (8) and (9), the amount of change in haze (ΔH = H ₁ −H ₀ ) of the sample film was calculated. The lower ΔH, the lower the amount of oligomer precipitation due to the high temperature treatment, and the better.

(11) Coefficient of dynamic friction A film cut to a width of 18 mm and a length of 120 mm is pasted onto a smooth glass plate having a width of 10 mm and a length of 100 mm so that the surface becomes a hard coat layer, and the surface is polyester on a metal pin having a diameter of 8 mm. The film was affixed to become a film. The metal pin was slid in the longitudinal direction of the glass plate under the condition of a load of 30 g and 40 mm / min to measure the friction force, and the friction coefficient at the point of slid by 10 mm was evaluated as the dynamic friction coefficient. The measurement was performed in an atmosphere of room temperature 23 ± 1 ° C. and humidity 50 ± 0.5% RH.

(12) Steel wool scratch resistance (SW resistance)
The hard coat layer was reciprocated 10 times with # 0000 steel wool applied with a load of 100 g by a Gakushin type abrasion resistance tester (manufactured by Tester Sangyo Co., Ltd.), and the damaged state of the hard coat layer was visually evaluated.
<Criteria>
○: When there are less than 10 scratches ×: When there are 10 or more scratches

(13) Film curl The sample film was cut into a 10 cm square, and the sample film was placed on a horizontal table with the raised surface as the upper surface. The rising of each vertex was measured and judged according to the following criteria.
<Criteria>
○: Lift of all vertices is less than 5 cm ×: Lift of any vertex is 5 cm or more

(14) Process contamination evaluation of transparent conductive film lamination (practical property substitution evaluation)
Reactive sputtering using a sintered body material of 95% by weight of indium oxide and 5% by weight of tin oxide in an atmosphere of 0.4 Pa composed of 95% by volume of argon gas and 5% by volume of oxygen gas on one side of the sample film By this method, an ITO film (transparent conductive thin film) having a thickness of 25 nm was formed. The ITO film was crystallized by heat treatment at 150 ° C. for 1 hour. Based on the image of roll conveyance, the determination was made according to the following criteria based on the state of oligomer adhesion when the obtained film was rubbed against a 3 inch φ iron rod.
<Criteria>
○: Oligomer adhesion to the metal rod is hardly observed (practical level)
×: Many oligomers are attached to the metal rod (practically problematic level)

(15) Heat resistance film and heating test after bonding (practical property substitution evaluation of heat resistance)
A silicone-based adhesive was applied to the sample film, and a heat-resistant film (polyimide) was bonded. After bonding, heat treatment was performed for 90 minutes in an oven maintained at 150 ° C., and the presence or absence of peeling was confirmed. Thereafter, the sample was cut into a 10 cm square, placed on a horizontal desk with the heat-resistant film facing down, the height from the desk at each vertex was measured, and the determination was made according to the following criteria.
<Criteria>
◯: There is no peeling, and the height from the desk at each vertex is 10 mm or less.
X: There is peeling, the height from the desk of any vertex is larger than 10 mm, and curls to the heat resistant film side. One or more of these phenomena occur.

(16) Blocking resistance Two sample pieces were prepared by cutting a sample film into a 10 cm square. One sample piece is fixed to the mirror surface of the SUS plate so that the hard coat layer is facing, and another sample piece is overlaid so that the hard coat layer surfaces are in contact with each other, and then the 5 kg roller is reciprocated five times. Crimped and subjected to blocking test. A load (area: 25 cm ² ) is applied from an angle of 45 °, and the load is measured when the sample film that is not fixed to the mirror surface of the SUS plate moves in the load direction due to slippage between the hard coat layer surfaces. The determination was made according to the following criteria.
<Criteria>
○: When the load for moving the test piece is 10 kg or less ×: When the load for moving the test piece exceeds 10 kg

  The polyester used in the examples and comparative examples was prepared as follows.

<Manufacture of polyester>
[Production Method of Polyester (I)]
Using 100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol as starting materials, adding tetrabutoxy titanate as a catalyst to the reactor, setting the reaction start temperature to 150 ° C., and gradually increasing the reaction temperature as methanol is distilled off. It was 230 degreeC after 3 hours. After further 4 hours, the transesterification reaction was substantially terminated. This reaction mixture was transferred to a polycondensation tank and subjected to a polycondensation reaction for 4 hours. During the polycondensation reaction, the temperature was gradually raised from 230 ° C. to 280 ° C. On the other hand, the pressure was gradually reduced from normal pressure, and finally 0.3 mmHg. After the start of the polycondensation reaction, the polycondensation reaction is stopped at the time when the intrinsic viscosity is equivalent to 0.55 dL / g due to the change in the stirring power of the polycondensation tank, the polymer is discharged under nitrogen pressure, and the intrinsic viscosity is 0.59 dL. / G, polyester (I) having an oligomer (ester cyclic trimer) content of 0.89% by weight was obtained.

[Production method of polyester (II)]
Polyester (I) is pre-crystallized in advance at 160 ° C. and then solid-phase polymerized in a nitrogen atmosphere at a temperature of 220 ° C., with an intrinsic viscosity of 0.72 dL / g and an oligomer (ester cyclic trimer) content. 0.46% by weight of polyester (II) was obtained.

[Production method of polyester (III)]
Polyester (I) was produced in the same manner as in the production method of polyester (I) except that aluminum oxide particles having an average particle diameter of 0.3 μm dispersed in ethylene glycol were added so that the content was 1.5% by weight. (III) was obtained. The obtained polyester (III) had an intrinsic viscosity of 0.59 dL / g and an oligomer (ester cyclic trimer) content of 0.87% by weight.

[Anchor layer]
Examples of compounds constituting the anchor layer are as follows.

(Example compounds)
Polyester resin (I): 92 mol% of 2,6-naphthalenedicarboxylic acid as an acid component, 8 mol% of sodium 5-sulfoisophthalate, 80 mol% of ethylene glycol and 20 mol% of diethylene glycol as a diol component Aqueous dispersion of polyester resin / acrylic resin (II): acrylic copolymer mainly composed of alkyl acrylate, alkyl methacrylate, methacrylic acid, N-methylolacrylamide (glass transition point: 50 ° C., acid value: 14 mg KOH, average particle size: 0.05 μm)
Epoxy compound (III): polyglycerol polyglycidyl ether (Denacol EX-521, manufactured by Nagase ChemteX Corporation)
Oxazoline compound (IV): an acrylic polymer having an oxazoline group and a polyalkylene oxide chain (Epocross WS-500, manufactured by Nippon Shokubai Co., Ltd., containing 38% by weight of 1-methoxy-2-propanol solvent)
Type)
Melamine compound (V): hexamethoxymethylmelamine Particle (VI): silica sol having an average particle size of 65 nm

[Hard coat layer]
Examples of compounds constituting the hard coat layer are as follows.

(Example compounds)
Hard coat main agent (α): acryloyl group-containing polyfunctional acrylate compound paint (dipentaerythritol hexaacrylate (DPHA) content: 30 to 40% by weight)
Hard coat oligomer (β1): isocyanate paint (containing hexamethylene diisocyanate (HDI) as the main agent)
Hard coat oligomer (β2): Bifunctional acrylate (containing 1,6-hexanediol diacrylate (HDDA) as the main agent)
Particle (γ): reactive silica (average particle diameter: 20 nm)
Initiator (Ω): Irgacure 127 (manufactured by BASF)

Example 1:
Two polyesters (II) and (III) were mixed at a ratio of 99% by weight and 1% by weight, respectively, as the raw material for the a layer, and 100% by weight of the polyester (I) as the raw material for the b layer. Each was supplied to an extruder and melted at 285 ° C., and then two layers and three layers (a layer / b layer) on a casting drum cooled to 40 ° C. with the a layer as both outer layers and the b layer as an intermediate layer. / A layer), the polyester film thickness composition ratio was co-extruded so as to be a layer: b layer: a layer = 2: 19: 2, and cooled and solidified to obtain a non-oriented sheet.
Next, after the film is stretched 3.3 times in the film running direction (MD) at a film temperature of 85 ° C. using the difference in roll peripheral speed, the materials constituting the anchor layer are (I) :( II) :( III): (IV): (V) = 31: 31: 15: 15: 5: 3 were mixed so as to have a weight ratio, and applied to one side of the film so that the anchor layer thickness after drying was 0.04 μm. Later, the film was guided to a tenter and stretched 5.1 times at 120 ° C in the direction perpendicular to the running direction of the film (TD). After heat treatment at 235 ° C, the film was relaxed in the transverse direction, and the film was wound on a roll. A laminated polyester film having a width of 1000 mm, a winding length of 6000 m, and a film thickness of 50 μm was obtained.
Next, on the anchor layer of the prepared laminated polyester film, the coating liquid having the blending ratio shown in Table 1 below (the numerical values in the table mean the weight ratio of each constituent unit) is diluted with MIBK (methyl isobutyl ketone), After applying by a reverse gravure coating method offline so that the thickness of the hard coat after drying and curing becomes 2 μm, heat treatment is performed at 90 ° C. for 60 seconds, and then with a high-pressure mercury lamp irradiation device (EUV482A: manufactured by Celitec). Light irradiation was performed at 300 mJ / cm ² . After that, in a hot air oven, the film was reheated (offline annealing) at 190 ° C. for 10 seconds at a film conveyance speed of 50 m / min under the condition of a film tension of 3 kg / 1000 mm width to form a hard coat film. Obtained. Various properties of the obtained hard coat film are shown in Table 2.

Example 2 and Example 3
A hard coat film was obtained in the same manner as in Example 1 except that the film thickness was changed. Various properties of the obtained hard coat film are shown in Table 2.

Example 4
A hard coat film was obtained in the same manner as in Example 1 except that the hard coat liquid 2 shown in Table 1 was changed. Various properties of the obtained hard coat film are shown in Table 2.

Example 5 and Example 6
A hard coat film was obtained in the same manner as in Example 4 except that the film thickness was changed. Various properties of the obtained hard coat film are shown in Table 2.

Example 7
A hard coat film was obtained in the same manner as in Example 1 except that the hard coat liquid 3 shown in Table 1 was changed. Various properties of the obtained hard coat film are shown in Table 2.

Examples 8 and 9
A hard coat film was obtained in the same manner as in Example 7 except that the film thickness was changed. Various properties of the obtained hard coat film are shown in Table 2.

Comparative Example 1
A hard coat film was obtained in the same manner as in Example 1 except that the hard coat layer was not provided. Table 3 shows various properties of the obtained hard coat film.

Comparative Example 2
A hard coat film was obtained in the same manner as in Example 1 except that offline annealing was not performed. Table 3 shows various properties of the obtained hard coat film.

Comparative Example 3
A hard coat film was obtained in the same manner as in Example 1 except that the film was guided to a tenter, stretched 5.1 times at 120 ° C. in the direction perpendicular to the running direction (TD), and heat treated at 255 ° C. Table 3 shows various properties of the obtained hard coat film.

Comparative Examples 4-6
A hard coat film was obtained in the same manner as in Example 1 except that the hard coat solutions 4 to 6 shown in Table 1 were changed. Table 3 shows various properties of the obtained hard coat film.

Claims (4)

A hard coat film laminated in the order of an anchor layer and a hard coat layer on at least one side of a polyester film,
The hard coat layer is a layer formed by curing a curable resin and particles having a polyfunctional acrylate compound containing at least two (meth) acryloyl groups in the molecule and an isocyanate compound as constituent units,
And shrinkage in the running direction of after heating at 0.99 ° C. 90 minutes film (MD) _{S MD} 0.05% to 0.25%, shrinkage _{S TD} direction (TD) perpendicular to the running direction of the film A hard coat film characterized by being -0.05% to 0.05%.   The hard coat film according to claim 1, wherein the polyfunctional acrylate compound containing two (meth) acryloyl groups has dipentaerythritol.   The hard coat film according to claim 1, wherein the isocyanate compound is hexamethylene diisocyanate.   The refractive index of the said hard-coat layer is 1.40-1.48, The hard coat film of any one of Claims 1-3 characterized by the above-mentioned.