WO2012144417A1

WO2012144417A1 - Coating film

Info

Publication number: WO2012144417A1
Application number: PCT/JP2012/060031
Authority: WO
Inventors: 神田俊宏; 藤田真人
Original assignee: 三菱樹脂株式会社
Priority date: 2011-04-18
Filing date: 2012-04-12
Publication date: 2012-10-26
Also published as: KR20140018194A; JP2012232580A; KR101768461B1; JP5562372B2

Abstract

Provided is a laminated polyester film which has a high standard of both adhesiveness and anti-static properties, which have conventionally been thought of as not being possible to achieve simultaneously. A coating film comprising a 0.01-0.07μm thick coating layer on at least one surface of a polyester film, said coating layer being formed from a coating agent containing: an acrylic resin (A) having a hydrophilic group, originating from a reactive emulsifier, in the molecule; a compound (B) having a quaternary ammonium group; and an oxazoline cross-linking agent (C).

Description

Coating film

The present invention relates to a coating film having excellent antistatic properties and excellent adhesion to various topcoats.

Biaxially stretched polyester film is excellent in transparency, dimensional stability, mechanical properties, heat resistance, electrical properties, etc., and is used in various fields.

In particular, in recent years, it is used as a surface protective film for optical members such as polarizing plates, retardation plates and laminates conforming thereto, and substrates for optical films such as lens sheets used for liquid crystal displays such as computers and televisions. Is increasing.

In such applications, various topcoats such as paints, inks, pressure-sensitive adhesives and adhesives are processed on polyester films. However, since the biaxially stretched polyester film has a highly crystallized surface, the biaxially stretched polyester film has a defect that it is inferior in adhesiveness to these various topcoats.

As one of the methods for solving such problems related to adhesiveness, there is a method in which various resins are applied to the surface of a polyester film and an application layer having easy adhesion performance is provided.

On the other hand, polyester films are characterized by the fact that they are easily charged due to static electricity as a common problem with plastic films. For this reason, problems such as poor running performance of processed films or processed products, attracting ambient dust, etc., and when optical films are used, multiple films stick to each other due to static electricity, causing the films to bend and causing unevenness in image quality. Problems arise. There is also a method of providing a coating layer having antistatic performance on the film for suppressing the charging of the polyester film (Patent Documents 1 and 2).

However, conventional antistatic coating layers are inferior in adhesiveness, and none of them have both adhesiveness and antistatic properties at a sufficient level.

JP-A-5-1164 Japanese Patent Laid-Open No. 8-143691

The present invention has been made in view of the above-mentioned problems, and the problem to be solved is to provide a coating film which has been considered to be incompatible with the past, and which has both adhesiveness and antistatic performance at a high level. It is in.

As a result of intensive studies on the above problems, the present inventors have found that the above problems can be easily solved by adopting a specific configuration, and the present invention has been completed.

That is, the gist of the present invention is a coating film having a coating layer having a thickness of 0.01 to 0.07 μm on at least one surface of a polyester film, wherein the coating layer has a hydrophilic group derived from a reactive emulsifier as a molecule. It exists in the coating film characterized by being a coating layer formed from the coating agent containing the acrylic resin (A) which has in it, the compound (B) which has a quaternary ammonium group, and an oxazoline type crosslinking agent (C). .

According to the present invention, it is possible to provide a coating film that has been considered to be incompatible with each other at a high level of adhesion and antistatic performance, and the industrial value of the present invention is high.

The base film of the coated film of the present invention is made of polyester. Such polyesters include dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, 4,4′-diphenyldicarboxylic acid, 1,4-cyclohexyldicarboxylic acid or esters thereof. It is a polyester produced by melt polycondensation with glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, and 1,4-cyclohexanedimethanol. Polyesters composed of these acid components and glycol components can be produced by arbitrarily using a commonly used method.

For example, a transesterification reaction between a lower alkyl ester of an aromatic dicarboxylic acid and a glycol, or a direct esterification of an aromatic dicarboxylic acid and a glycol, to form a substantially bisglycol of an aromatic dicarboxylic acid A method is employed in which an ester or a low polymer thereof is formed and then polycondensed by heating under reduced pressure. Depending on the purpose, an aliphatic dicarboxylic acid may be copolymerized.

Typical examples of the polyester of the present invention include polyethylene terephthalate, polyethylene-2,6-naphthalate, poly-1,4-cyclohexanedimethylene terephthalate, and the like. It may be a polymerized polyester and may contain other components and additives as necessary.

In the polyester film of the present invention, particles can be contained for the purpose of ensuring the running property of the film and preventing scratches. Examples of such particles include inorganic particles such as silica, calcium carbonate, magnesium carbonate, calcium phosphate, kaolin, talc, aluminum oxide, titanium oxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, and molybdenum sulfide. Further, organic particles such as crosslinked polymer particles and calcium oxalate, and precipitated particles during the polyester production process can be used.

The particle size and content of the particles used are selected according to the use and purpose of the film, but the average particle size (d50) is usually 0.01 to 3 μm, preferably 0.02 to 2.5 μm, more preferably Is in the range of 0.03 to 2 μm. If the average particle size exceeds 3.0 μm, the surface roughness of the film may become too rough, or the particles may easily fall off from the film surface. When the average particle size is less than 0.01 μm, the surface roughness is too small and sufficient slipperiness may not be obtained.

The particle content is usually in the range of 0.0003 to 1.0% by weight, preferably 0.0005 to 0.5% by weight, based on the polyester. When the particle content is less than 0.0003% by weight, the slipperiness of the film may be insufficient. On the other hand, when the content exceeds 1.0% by weight, the transparency of the film is poor. It may be enough. In addition, when it is particularly desired to ensure transparency, smoothness, etc. of the film, it can also be configured so as not to substantially contain particles. In addition, various stabilizers, lubricants, antistatic agents and the like can be appropriately added to the film.

In addition, it is preferable that the haze of the coating film of this invention is 10% or less. More preferably, it is 5% or less, More preferably, it is 3% or less. If it is larger than this range, it may be difficult to use in optical film applications.

As a film forming method of the film of the present invention, a generally known film forming method can be adopted, and there is no particular limitation. For example, a sheet obtained by melt extrusion is first stretched 2 to 6 times at 70 to 145 ° C. by a roll stretching method to obtain a uniaxially stretched polyester film, and then perpendicular to the previous stretching direction in a tenter. A film can be obtained by stretching 2 to 6 times in the direction at 80 to 160 ° C. and further performing heat treatment at 150 to 250 ° C. for 1 to 600 seconds. Further, at this time, a method of relaxing 0.1 to 20% in the longitudinal direction and / or the transverse direction in the heat treatment zone and / or the cooling zone at the heat treatment outlet is preferable.

The polyester film in the present invention has a single layer or a multilayer structure. In the case of a multilayer structure, the surface layer and the inner layer, or both the surface layer and each layer can be made of different polyesters depending on the purpose.

The coating layer of the present invention can be provided by either a so-called off-line coating in which a coating layer is provided later on a formed film or a so-called in-line coating in which a coating layer is provided during film formation. However, it is preferably provided by in-line coating, particularly a coating stretching method in which stretching is performed after coating.

In-line coating is a method of coating within the process of manufacturing a polyester film. Specifically, it is a method of coating at any stage from melt extrusion of polyester to biaxial stretching and then heat setting and winding. is there. Normally, it is coated on either a substantially amorphous unstretched sheet obtained by melting and quenching, then a uniaxially stretched film stretched in the longitudinal direction (longitudinal direction), or a biaxially stretched film before heat setting. To do. In particular, as a coating stretching method, a method of stretching in the transverse direction after coating on a uniaxially stretched film is excellent. According to such a method, film formation and coating layer coating can be performed at the same time, so there is an advantage in manufacturing cost. Stabilize. In addition, the polyester film before being biaxially stretched is first coated with the resin layer constituting the coating layer, and then the base film and the coating layer are firmly adhered by stretching the film and the coating layer simultaneously. become. In addition, the biaxial stretching of the polyester film is achieved by stretching the film in the lateral direction while holding the film end with a tenter clip, so that the film is constrained in the longitudinal / lateral direction, and no wrinkles or the like are formed in the heat setting. High temperature can be applied while maintaining the nature. Therefore, since the heat treatment performed after coating can be performed at a high temperature that cannot be achieved by other methods, the film forming property of the coating layer is improved, and the coating layer and the polyester film are firmly adhered. As the polyester film provided with the coating layer, the uniformity of the coating layer, the improvement of the film forming property, and the adhesion between the coating layer and the film often produce preferable characteristics. However, since heat resistance is required for the resin used as the coating layer, it is necessary to sufficiently study the selection of the resin to be used.

In the case of the coating stretching method, the coating solution to be used is preferably an aqueous solution or an aqueous dispersion for safety reasons in terms of handling, working environment, but water is the main medium and does not exceed the gist of the present invention. If so, an organic solvent may be contained.

The coating layer of the present invention comprises a coating solution containing an acrylic resin (A) having a hydrophilic group derived from a reactive emulsifier in its molecule (A), a compound (B) having a quaternary ammonium group, and an oxazoline crosslinking agent (C). It can be obtained by coating, drying and curing on a film. The coating solution may contain other components.

When each component is not completely reacted, the resulting coating layer contains both unreacted products and reaction products of each component, and the ratio of the reaction product and unreacted product depends on the curing conditions. It can be changed as appropriate.

As described above, in the conventional technology, adhesiveness and antistatic performance are not compatible at a sufficient level. The reason for this is not always clear, but we believe that there are the following reasons.

That is, to obtain sufficient antistatic performance by coating, it is necessary to thicken the coating layer in order to obtain the necessary amount of antistatic component, but such a thick coating layer is a test method for adhesion. When the forced peeling test is performed after the top coat is processed, the coating layer itself tends to cohesive failure in addition to peeling at the interface between the coating layer and the top coat layer. Therefore, sufficient adhesiveness could not be ensured. In order to prevent this cohesive failure, for example, if the cohesive strength of the coating layer itself is increased by using a cross-linking agent, the antistatic component network in the coating layer is inhibited, and the antistatic performance is reduced, or coating is applied to prevent cohesive failure. When the layer is thinned, the total amount of antistatic components is reduced, and the antistatic performance is lowered. In addition, when the ratio of the antistatic component to the effective component of the entire coating layer is increased instead of increasing the thickness of the coating layer, if these components have poor adhesion, the resulting coating layer also has high adhesion. I couldn't.

In other words, in order to achieve both antistatic performance and adhesiveness, it was necessary to find a new combination in the selection of materials to be used and the configuration of the coating layer.

The acrylic resin (A) is a polymer composed of a polymerizable monomer having a carbon-carbon double bond, as typified by an acrylic or methacrylic monomer.

Examples of the polymerizable monomer having a carbon-carbon double bond include various carboxyl group-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, fumaric acid, maleic acid, citraconic acid, and the like. Various hydroxyl group-containing monomers such as salts, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, monobutylhydroxy fumarate, monobutylhydroxy itaconate , Various (meth) acrylic esters such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate, (meth) acrylimide, di Acetone acrylic Various nitrogen-containing vinyl monomers such as N-methylolacrylamide or (meth) acrylonitrile, various styrene derivatives such as styrene, α-methylstyrene, divinylbenzene, vinyltoluene, vinyl acetate, vinyl propionate, etc. In particular, in the present invention, a copolymer containing one or more of acrylic acid, methacrylic acid, acrylic acid ester, and methacrylic acid ester is preferable.

Further, in obtaining an acrylic resin by polymerizing such monomers, in the present invention, it is preferably obtained in the form of an aqueous dispersion using an emulsion polymerization method in which monomers are dispersed and polymerized in water. An emulsifier is used to disperse the monomer in water. In the present invention, it is particularly preferable to use a nonionic or anionic reactive emulsifier. For acrylic resins obtained using other emulsifiers, the resulting coating layer may not exhibit sufficient adhesion. The reactive emulsifier here refers to an emulsifier having a radical polymerizable double bond in the molecule and copolymerizing in the resin during the polymerization of the acrylic resin. It is particularly preferable that it is nonionic, and in that case, a hydrophilic group using an alkylene oxide is preferable. In the case of an anionic property, a sulfate group is preferable as the hydrophilic group.

The average dispersion particle size of the obtained acrylic resin aqueous dispersion is usually 0.01 to 0.2 μm, preferably 0.02 to 0.09 μm. When the average dispersed particle size is larger than the above range, the appearance and adhesion of the resulting coating layer tend to be inferior. If it is smaller than the above range, the adhesiveness tends to be inferior.

The compound (B) having a quaternary ammonium group refers to a compound having a quaternized ammonium group in the molecule, and is particularly preferably a polymer compound. Moreover, it is preferable that it is a water-soluble compound.

In the present invention, for example, a polymer containing a monomer having a quaternary ammonium group and an unsaturated double bond as components can be used.

Specific examples of such a polymer include a polymer having a constituent represented by the following formula 1 or 2 as a repeating unit. These homopolymers and copolymers, and other plural components may be copolymerized.

In the above formula (1), R ¹ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ² is —O— or —NH—, and R ³ is —R ⁷ — or —R ⁷ —AR ^8. -(Wherein R ⁷ and R ⁸ are an optionally substituted alkylene group having 1-6 carbon atoms, A represents -O-, -NH- or -N (CH ₃ ) ₂ ⁺ -), R ⁴ , R ⁵ and R ⁶ are each a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X ⁻ is a monovalent anion.

In the above formula (2), R ¹ and R ² are each a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X ⁻ is a monovalent anion.

The polymer having the constituent represented by the above formula 1 is preferable because of the excellent transparency of the resulting coating layer. However, the coating stretching method may be inferior in heat resistance, and when used in the coating stretching method, X ⁻ is preferably not a halogen.

The component represented by the above formula (2) and other compounds in which the quaternary ammonium base is in the polymer skeleton are excellent in heat resistance, and it is easy to obtain antistatic properties even in a coating stretching method.

The oxazoline-based crosslinking agent (C) refers to a compound having an oxazoline group in the molecule. The compound having an oxazoline group can be synthesized using a monomer having an oxazoline group as at least one of raw material monomers. Examples of such monomers include 2-vinyl-2-oxazoline, 5-methyl-2-vinyl-2-oxazoline, 4,4-dimethyl-2-vinyl-2-oxazoline, and 4,4-dimethyl-2- Vinyl-5,6-dihydro-4H-1-oxazine, 4,4,6-trimethyl-2-vinyl-5,6-dihydro-4H-1,3-oxazine, 2-isopropenyl-2-oxazoline, 4, 4-dimethyl-2-isopropenyl-2-oxazoline, 4-acryloyl-oxymethyl-2,4-dimethyl-2-oxazoline, 4-methacryloyl-oxymethyl-2,4-dimethyl-2-oxazoline, 4-methacryloyl -Oshimethyl-2-phenyl-4-methyl-2-oxazoline, 2- (4-vinylphenyl) -4,4-dimethyl-2-oxy Gelsolin, 4-ethyl-4-hydroxymethyl-2-isopropenyl-2-oxazoline can be exemplified 4-ethyl-4-ethoxymethyl-2-isopropenyl-2-oxazoline and the like. One or more of these or other oxazoline group-containing monomers can be used.

In the present invention, it is preferable that other components not containing an oxazoline group are copolymerized. Here, the other component is not particularly limited as long as it is a monomer that can be copolymerized with an oxazoline group-containing monomer. For example, a resin copolymerized with a vinyl oxazoline monomer using a monomer containing a vinyl group, such as (meth) acrylic acid esters, (meth) acrylamides, and styrene monomers, has high reactivity and is industrially obtained. Cheap.

In the coating solution for providing the coating layer, components other than those described above can be included as necessary. For example, surfactants, other binders and antistatic agents, lubricants, particles, antifoaming agents, coatability improving agents, thickeners, antioxidants, ultraviolet absorbers, foaming agents, dyes, pigments and the like. These additives may be used alone or in combination of two or more as necessary.

As a ratio in the non-volatile component of the coating liquid, the ratio of the acrylic resin (A) having a hydrophilic group derived from the reactive emulsifier in the molecule is usually 5 to 70% by weight, preferably 15 to 50% by weight, quaternary The proportion of the compound (B) having an ammonium group is usually 10 to 80% by weight, preferably 20 to 70% by weight, and the proportion of the oxazoline-based crosslinking agent (C) is usually 5 to 60% by weight, preferably 10 to 40%. % By weight. The coating layer eventually becomes a mixture of these components and their reactive organisms.

The thickness of the coating layer is 0.01 to 0.07 μm, preferably 0.02 to 0.05 μm, as the film thickness on the finally obtained film.

When the composition of the coating layer is limited as described above and the thickness of the coating layer is within the above range, the adhesiveness and the antistatic performance are compatible at a high level.

The antistatic property of the coating layer is measured by the surface specific resistance of the coating layer. It can be said that the lower the surface resistivity, the better the antistatic property. If the surface resistivity is 1 × 10 ¹³ Ω or less, it can be said that there is no problem with antistatic properties, and if it is 1 × 10 ¹² Ω or less, it can be said that the antistatic properties are extremely good.

As a method of applying the coating solution to the polyester film, for example, a coating technique as shown in “Coating system” published by Yuji Harasaki, Tsuji Shoten, published in 1979 can be used. Specifically, air doctor coater, blade coater, rod coater, knife coater, squeeze coater, impregnation coater, reverse roll coater, transfer roll coater, gravure coater, kiss roll coater, cast coater, spray coater, curtain coater, calendar coater And a technique such as an extrusion coater.

In addition, in order to improve the applicability and adhesion of the coating agent to the film, the film may be subjected to chemical treatment, corona discharge treatment, plasma treatment, etc. before coating.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In addition, the evaluation method in an Example and a comparative example is as follows.

(1) Measurement of intrinsic viscosity of polyester:
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) Average particle diameter (d50) of particles added to the polyester film:
The particle size was measured by a sedimentation method based on Stokes' resistance law using a Shimadzu centrifugal sedimentation type particle size distribution analyzer SA-CP3.

(3) Average particle size of the coating composition:
The aqueous dispersion of the coating composition was diluted to an appropriate concentration, and the 50% average diameter of the number average was measured with Nikkiso Microtrac UPA.

(4) Coating layer thickness:
The film was fixed with an embedding resin, the cross section was cut with a microtome, and the 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 coating layer was measured. A total of 15 points on the film are measured, and the average of 9 points excluding 3 points from the larger value and 3 points from the smaller value is defined as the coating layer thickness.

(5) Antistatic property:
Using a high resistance measuring instrument made by Hewlett-Packard Japan: HP4339B and a measuring electrode: HP16008B, the sample was conditioned for 30 minutes in a measurement atmosphere at 23 ° C. and 50% RH, and then the surface resistivity was measured.

(6) Adhesiveness:
On the coating layer of the sample, the active energy ray-curable resin composition as shown below was applied so that the thickness after curing was 7 μm, and dried in a hot air drying oven set at 80 ° C. for 1 minute. It was. Next, using a high-pressure mercury lamp with an energy of 120 W / cm, curing was performed by irradiation for about 7 seconds at an irradiation distance of 100 mm to obtain a laminated film in which an active energy ray-curable resin layer was provided on the film. The integrated light amount of the active energy ray at this time was measured using an ultraviolet integrated light meter UIT-250 and a light receiver UVD-C365 (manufactured by USHIO INC.), And was about 110 mJ / cm ² . The active energy ray-cured resin layer of the obtained laminated film is cross-cut so that there are 100 grids per inch, and 18 mm wide tape (Nichiban cello tape (registered trademark) CT-18) Was attached, and a rapid peel test was conducted. The adhesiveness was evaluated by the peeled area. The evaluation of adhesiveness was performed in five stages A to E shown below. A indicates the highest class and E indicates the lowest class. .

A: Number of cross-cuts peeled = 0
B: 1 ≦ Number of cross-cuts ≦ 10
C: 11 ≦ number of cross cuts ≦ 20
D: 21 <Number of cross cuts E: Full peel

Cured resin composition: Nippon Kayaku “KAYARAD DPHA” 80 parts by weight, Nippon Kayaku “KAYARAD R-128H” 20 parts by weight, Ciba Specialty Chemicals “IRGACURE 651” 5 parts by weight diluted with toluene And a concentration of 30% by weight.

(7) Transparency:
According to JIS K 7136 (ISO14782), haze of the film was measured using a turbidimeter “NDH2000” (manufactured by Nippon Denshoku Industries Co., Ltd.). It can be said that the lower the haze, the better the transparency.

The polyester raw materials used in Examples and Comparative Examples are as follows.
(Polyester 1): Polyethylene terephthalate having an intrinsic viscosity of 0.66 that does not substantially contain particles (Polyester 2): containing 0.3% by weight of amorphous silica having an average particle diameter (d50) of 1.6 μm, Polyethylene terephthalate with intrinsic viscosity of 0.65

Moreover, the following was used as a coating composition.
(E1): a polymer compound having a number average molecular weight of 20000, obtained by copolymerizing a structural unit of the following formula 1-1 and a structural unit of the following formula 1-2 at a weight ratio of 95/5

(E2): a polymer compound composed of a structural unit of the following formula 2-1

(E3): a polymer compound having a structure in which a structural unit of the following formula 3-1 and an acrylate ester are copolymerized

(A): Copolymerized mainly with alkyl acrylate ester, alkyl methacrylate ester, methacrylic acid, N-methylol acrylamide in the presence of alkoxy polyethylene glycol methacrylate as reactive emulsifier, glass transition point of 50 ° C., acid Acrylic resin (C1) having a valence of 14 mgKOH and an average particle size of 0.05 μm: “Epocross WS-500” (manufactured by Nippon Shokubai Co., Ltd.), a polymer-type cross-linking agent in which an oxazoline group is branched to an acrylic resin
(C2): Becamine “J-101” (made by Nippon Materials), which is methoxymethylol melamine
(C3): “Denacol EX-521” (manufactured by Nagase ChemteX), which is a polyglycerol polyglycidyl ether
(F): Silica sol aqueous dispersion having an average particle size of 0.07 μm (S): Surfactant “Surfinol 465” (manufactured by Air Products)

Comparative Example 1:
A blend of polyester 1 and polyester 2 at a weight ratio of 92/8 was used as the raw material for layer A, and polyester 1 alone was used as the raw material for layer B. To the outer layer (surface layer) and the B layer as an intermediate layer, and coextruded in a layer configuration of two types and three layers (A / B / A) using an electrostatic adhesion method. The film was cooled and solidified while being in close contact with a mirror surface cooling drum having a surface temperature of 40 to 50 ° C. to prepare an unstretched polyethylene terephthalate film having a thickness composition ratio of A / B / A = 3/94/3. This film was stretched 3.7 times in the longitudinal direction while passing through a heating roll group at 85 ° C. to obtain a uniaxially oriented film. Next, this film was guided to a tenter stretching machine, stretched 4.0 times in the width direction at 100 ° C., further heat treated at 230 ° C., and then subjected to a relaxation treatment of 2% in the width direction. An axially oriented polyethylene terephthalate film was obtained. The properties of this film are shown in Table 2 below.

Example 1:
A coating solution as shown in Table 1 below was applied to one side of a uniaxially oriented film obtained in the same process as Comparative Example 1. Next, the film was guided to a tenter stretching machine, and the coating composition was dried using the heat, and on the biaxially oriented polyethylene terephthalate film having a film thickness of 100 μm by the same process as in Comparative Example 1, A laminated polyester film provided with a coating layer having a thickness shown in Table 1 was obtained. The properties of this film are shown in Table 2.

Examples 2 to 5 and Comparative Examples 2 to 6:
In the same process as Example 1, the coating solution was changed as shown in Table 1 to obtain a laminated polyester film in which a coating layer having a thickness shown in Table 1 was provided on a base film having a film thickness of 100 μm. . The properties of this film are shown in Table 2.

The coated film of the present invention can be suitably used as a biaxially stretched polyester film in applications that require excellent antistatic properties and adhesion to various topcoats.

Claims

A coating film having a coating layer having a thickness of 0.01 to 0.07 μm on at least one surface of a polyester film, wherein the coating layer has an acrylic resin (A ) A coating film, which is a coating layer formed from a coating agent containing a compound (B) having a quaternary ammonium group and an oxazoline-based crosslinking agent (C).
The coated film according to claim 1, wherein the compound having a quaternary ammonium group is a polymer having a constituent represented by the following formula 1 or 2 as a repeating unit.

In the above formula (1), R 1 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R 2 is —O— or —NH—, and R 3 is —R 7 — or —R 7 —AR 8. -(Wherein R 7 and R 8 are an optionally substituted alkylene group having 1 to 6 carbon atoms, A represents -O-, -NH- or -N (CH 3 ) 2 + -), R 4 , R 5 and R 6 are each a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X − is a monovalent anion.

In the above formula (2), R 1 and R 2 are each a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X − is a monovalent anion.
The proportion of the acrylic resin (A) having a hydrophilic group derived from the reactive emulsifier in the molecule is 5 to 70% by weight and the proportion of the compound (B) having a quaternary ammonium group as a proportion in the nonvolatile component of the coating liquid. The coated film according to claim 1 or 2, wherein 10 to 80% by weight of oxazoline-based crosslinking agent (C) is 5 to 60% by weight.
4. The coated film according to claim 1, wherein the coating layer has a surface resistivity P of 1 × 10 13 Ω or less.
The coated film according to any one of claims 1 to 4, wherein the film haze is 10% or less.