JP5753116B2 - Laminated polyester film - Google Patents

Description

  The present invention relates to a polyester film having an excellent antistatic property and a coating layer having excellent adhesion to various topcoats.

  Biaxially stretched polyester film excels in transparency, dimensional stability, mechanical properties, heat resistance, electrical properties, gas barrier properties, chemical resistance, etc., packaging materials, plate making materials, display materials, transfer materials, building materials, It is used for window paste materials, membrane switches, antireflection films used for flat displays and the like, optical films such as diffusion sheets and prism sheets, and transparent touch panels. In such applications, various top coats 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, it has a drawback that it is inferior in adhesion to these various topcoats.

  For this reason, as one method for improving the adhesiveness of the biaxially stretched polyester film, a method has been proposed in which various resins are applied to the surface of the polyester film to provide an application layer having easy adhesion performance. However, when processing solvent-free active energy ray curable resin on the surface of polyester film, it does not contain organic solvent, so it has low penetration and swelling hardening to easy-adhesion layer on polyester film and is generally used. The easy adhesion layer tends to have insufficient adhesion.

  On the other hand, the polyester film has a characteristic that it is easily charged due to static electricity as a problem common to 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. As for suppression of charging of the polyester film, there is a method of providing a coating layer having antistatic performance on the film.

  In relation to the above problems, Patent Documents 1 to 4 propose a polyester film having a coating layer containing a cationic antistatic agent and having good runnability on a coater. Furthermore, among these, the use of polyester, polyacrylate and polyurethane binders together with a cationic antistatic agent is disclosed in the coating layer in order to improve adhesion.

  In Patent Documents 1 to 4, there is a temporary effect on the above-described antistatic property and adhesion improvement. However, in such applications, the environment used may be harsh, and a substrate film having stronger adhesiveness is being marketed while maintaining antistatic performance as described in Patent Documents 1 to 4. It has been demanded.

JP-A-5-1164 Japanese Patent Laid-Open No. 8-143691 Japanese Patent Laid-Open No. 2008-81551 JP 2008-81552 A

  The present invention has been made in view of the above circumstances, and the problem to be solved is a polyester film having a coating layer that is compatible with antistatic properties and easy adhesion properties at a high level, which has been considered to be incompatible with the conventional technology. Is to provide.

  As a result of intensive studies on the above problems, the present inventors have found that the above problems can be solved by providing a coating layer containing a specific type of compound, and the present invention has been completed. .

That is, the gist of the present invention is that a polyurethane resin (A) containing a compound obtained by quaternizing a tertiary amino group of a chain extender having a tertiary amino group in the molecule and a polycarbonate polyol as constituent units , carbon- a polyurethane resin (B) containing 0.7 to 2.0 wt% of the double bonds of the carbon and polyester polyol Lumpur as a constituent unit, the cationic polymer antistatic agent (C), and oxazoline compounds (D) A laminated polyester film characterized by having a coating layer formed by applying a coating solution containing and dried on at least one side.

  ADVANTAGE OF THE INVENTION According to this invention, the polyester film which has a coating layer excellent in antistatic property and easy-adhesion with respect to topcoat can be provided, and the industrial value of this invention is high.

  The base film of the laminated polyester 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.

  The polyester film in the present invention can contain particles for the purpose of ensuring the film runnability 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 is usually in the range of 0.01 to 5.0 μm. If the average particle size exceeds 5.0 μm, the surface roughness of the film becomes too rough, or the particles are likely to 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. About particle | grain content, it is 0.0003 to 1.0 weight% normally with respect to polyester, Preferably it is the range of 0.0005 to 0.5 weight%. When the particle content is less than 0.0003% by weight, the slipperiness of the film may be insufficient. 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. Further, various stabilizers, lubricants and the like can be appropriately added to the film.

  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 the tenter. A film is obtained by extending | stretching 2 to 6 times at 80-160 degreeC to the direction, and also heat-processing at 150-250 degreeC 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 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 polyester film in the present invention has a coating layer on at least one surface, but even if a similar or other coating layer or functional layer is provided on the opposite surface of the film, it is naturally included in the concept of the present invention.

  As the coating layer in the present invention, a so-called in-line coating in which a coating layer is provided during film formation, particularly a coating stretching method in which stretching is performed after coating is suitably used.

  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, since film formation and coating layer coating can be performed at the same time, there is a merit in manufacturing cost. Stabilize. Moreover, the polyester film before biaxial stretching is first covered with a 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 is flat without wrinkles or the like in 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.

  In this case, the coating liquid to be used is preferably an aqueous solution or an aqueous dispersion for safety reasons in terms of handling, work environment, and water as a main medium, as long as it does not exceed the gist of the present invention. An organic solvent may be contained.

  Next, the coating layer provided on the film in the present invention will be described.

  The polyurethane resin (A) (B) contained in the coating solution for forming the coating layer in the present invention is a polymer compound having a urethane bond in the molecule, and is usually obtained by a reaction between a polyol and an isocyanate. Created. Examples of the polyol include polycarbonate polyols, polyester polyols, polyether polyols, polyolefin polyols, acrylic polyols, etc. These compounds may be used alone or in combination.

  In the present invention, the polyurethane resin (A) needs to contain a polycarbonate polyol as a constituent unit as a polyol.

  Examples of the polycarbonate polyol include those obtained by using a transesterification reaction between a diol and a lower dialkylene carbonate such as diethyl carbonate or a carbonate such as diphenyl carbonate and a diol directly with the diol. . In the present invention, as the diol, 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 Polycarbonate polyols using diol, neopentyl glycol, 3-methyl-1.5-pentanediol, 3,3-dimethylol heptane and the like can be used. Among these polycarbonate polyols, those using 1,6-hexanediol as the diol are particularly preferable because they have good adhesion and are easily industrially available.

  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.) and those having derivative units of lactone compounds such as polycaprolactone.

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

  In order to improve the adhesion to various topcoat layers, it is preferable to use polyester polyols in combination with polycarbonate polyols.

  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. These polyisocyanate compounds may be a dimer, a trimer represented by an isocyanuric ring, or a higher polymer.

  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 polyurethane resin (A) contained in the coating solution for forming the coating layer in the present invention is a compound obtained by quaternizing the tertiary amino group of the chain extender having a tertiary amino group in the molecule. It must be included as a structural unit. Thereby, the polyurethane resin (A) becomes self-emulsifying, and it is possible to make a stable dispersion in a medium mainly composed of water without adding an emulsifier. In particular, the stability and coating appearance of the coating solution of the present invention can be improved.

  As the chain extender used in the polyurethane resin (A) of the present invention, N-alkyl dialkanolamines such as N-methyldiethanolamine and N-ethyldiethanolamine, N-methyldiaminoethylamines, N-ethyldiaminoethylamines and the like N- Examples thereof include alkyldiaminoalkylamine and triethanolamine. These chain extenders having a tertiary amino group can be used alone or in combination of two or more. Moreover, the addition amount of these chain extenders is preferably 5 to 15% by weight based on the polyurethane resin (A).

  In the present invention, the chain extender having the tertiary amino group introduced into the polyurethane resin is neutralized with an acid or a cationic polyurethane resin containing a compound quaternized with a quaternizing agent. There is a need. When the tertiary amino group is neutralized with an acid, the acid is an organic acid such as formic acid, acetic acid, propionic acid, butyric acid, lactic acid, malic acid, malonic acid or adipic acid, and inorganic such as hydrochloric acid, phosphoric acid or nitric acid. Mention may be made of acids. These acids can be used alone or in combination of two or more. When the tertiary amino group is quaternized with a quaternizing agent, examples of the quaternizing agent include alkyl halides such as benzyl chloride and methyl chloride, and sulfate esters such as dimethyl sulfate and diethyl sulfate. Can do. These quaternizing agents can be used alone or in combination of two or more.

  The polyurethane resin (A) used in the present invention can be obtained by adding and reacting a polyisocyanate, a polycarbonate polyol, and a chain extender having a tertiary amino group in the molecule, followed by quaternization. Quaternized compounds can also be reacted as chain extenders.

  The urethane resin in the present invention 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 the 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 coating layer. The polyurethane resin (A) is preferably self-emulsified with a compound obtained by quaternizing the tertiary amino group of the chain extender having the tertiary amino group, and the polyurethane resin (B) having a carbon-carbon double bond is used. Examples of the ionic group to be introduced include various groups such as a carboxyl group, a sulfonic acid, a phosphoric acid, a phosphonic acid, a quaternary ammonium salt, and the carboxyl group is preferable.

  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, dimethylolpropanoic acid, dimethylolbutanoic acid, bis- (2-hydroxyethyl) propionic acid, bis- (2-hydroxyethyl) butanoic acid, etc. 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 a neutralizing agent is removed in a 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 obtained coating layer, as well as excellent stability in a liquid state before coating.

  In the present invention, the polyurethane resin (B) contained in the coating solution for forming the coating layer needs to contain a carbon-carbon double bond portion.

  The coating layer in the present invention is particularly capable of improving adhesion with a solventless active energy ray-curable layer.

  The presumed mechanism for improving adhesion is to form a carbon-carbon double bond and an active energy ray-curable layer in the coating layer of the film of the present invention by ultraviolet rays irradiated when forming the active energy ray-curable layer. The compound used is reacted with a carbon-carbon double bond to form a covalent bond.

  The carbon-carbon double bond of the polyurethane resin (B) having a carbon-carbon double bond used for forming the coating layer of the film of the present invention is contained in the compound that forms the active energy ray-curable layer. Any conventionally known material can be used as long as it reacts with a carbon-carbon double bond. In addition, the polyurethane resin having a carbon-carbon double bond in the terminal group is contained in the compound forming the active energy ray-curable layer rather than the polyurethane resin having a carbon-carbon double bond in the main chain. Reacts efficiently with carbon-carbon double bonds, which is advantageous. Examples of conventionally known materials include introduction into a polyurethane resin in the form of an acrylate group, a methacrylate group, a vinyl group, an allyl group, or the like.

  Various substituents can be introduced into the carbon-carbon double bond, such as an alkyl group such as a methyl group or an ethyl group, a phenyl group, a halogen group, an ester group, an amide group, or a conjugated double bond. You may have such a structure. Further, the amount of the substituent is not particularly limited, and any of a 1-substituted product, a 2-substituted product, a 3-substituted product, or a 4-substituted product can be used. A 2-substituted product is preferable, and a 1-substituted product is more preferable.

  A compound containing a tertiary amino group quaternized as a chain extender having a tertiary amino group in one polyurethane molecule, a polycarbonate polyol, and a carbon-carbon double bond as a constituent unit is industrial. Can be used in place of the polyurethane resin (A) and the polyurethane resin (B) having a carbon-carbon double bond in combination, and are included in the concept of the present invention.

  In the present invention, the cationic polymer antistatic agent (C) contained in the coating liquid for forming the coating layer refers to a compound having an ammonium group quaternized in the molecule, and is a water-soluble compound. Preferably there is. In the present invention, for example, a polymer containing a monomer having a quaternary ammonium group as a component 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, R ¹ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, R ² is —O— or —NH—, R ³ is an alkylene group having 1 to 6 carbon atoms or the structure of formula 1 Other possible structures, R ¹ , R ² and R ³ 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, 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 component represented by the above formula 1 is excellent in transparency of the resulting coating layer and is preferable. However, in the coating stretching method, heat resistance may be inferior, and when used in the coating stretching method, X ⁻ is preferably not a halogen.

  The compound represented by the above formula 2 and other compounds having a quaternary ammonium base in the polymer skeleton are excellent in heat resistance, and antistatic properties are easily obtained even in the coating stretching method.

  In the present invention, the coating solution for forming the coating layer contains the oxazoline compound (D). The oxazoline compound (D) in the present invention refers to a compound having an oxazoline group in the molecule, and can be synthesized using a monomer containing 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, 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-oxymethyl-2-phenyl-4-methyl-2-oxazoline, 2- (4-vinylphenyl) -4,4-dimethyl-2-o Oxazoline, 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.

  Moreover, in this invention, it is preferable to copolymerize the other component which does not contain an oxazoline group. 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. The coating solution may contain other cross-linking agents.

  In the biaxially stretched polyester film of the present invention, inorganic or organic fine particles can be added for the purpose of imparting slipperiness on the surface of the coating layer and improving blocking resistance. The fine particles include silica, alumina, titanium oxide, silica-alumina composite, silica-titanium oxide composite, cross-linked acrylic resin, cross-linked polystyrene resin and the like, or tin oxide, indium-tin composite oxide fine particles, antimony- It is preferable to contain at least one selected from conductive fine particles such as tin composite oxide fine particles. The fine particles to be added preferably have an average particle diameter of 5 to 200 nm, and the addition amount is also preferably 10% by weight or less based on the entire coating layer.

  A surfactant can be added to the coating layer of the biaxially stretched polyester film in the present invention. As this surfactant, a nonionic surfactant such as an acetyleglycol derivative substituted with an alkylene oxide addition polymer can be preferably used for the purpose of improving the wettability of the coating solution. Further, for the purpose of maintaining the transparency of the coating layer in the step of stretching the coating layer together with the film, a polyalkylene oxide adduct of glycerin or a polyalkylene oxide adduct of polyglycerin can be used.

  In addition to the above-described components, for example, an antifoaming agent, a thickening agent, an antioxidant, an ultraviolet absorber, a foaming agent, a dye, and a pigment can be added to the coating layer as necessary. These additives may be used alone or in combination of two or more as necessary.

The coating layer of the biaxially stretched polyester film in the present invention has a coating amount of 0 as a final dry film after being dried and solidified, or after being biaxially stretched and heat-set. .005~1.0g / ^{m 2,} more preferably in the range of 0.01 to 0.5 g / ^{m 2.} If the coating amount is less than 0.005 g / m ² , the antistatic performance and adhesiveness may be insufficient. If it exceeds 1.0 g / m ² , the antistatic performance and adhesiveness are no longer saturated. On the contrary, there is a tendency that harmful effects such as blocking are likely to occur.

The surface specific resistance value of the coating layer of the present invention is usually 1 × 10 ¹² Ω or less, preferably 1 × 10 ¹¹ Ω or less, more preferably 1 × 10 ¹⁰ Ω or less, and the lower limit is not particularly limited. 1 × 10 ⁸ Ω.

  As a method for 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 techniques such as an extrusion coater and a bar coater.

  In addition, in order to improve the applicability | paintability to the film of a coating agent and adhesiveness, you may give a chemical process, a corona discharge process, a plasma process, etc. to a film before application | coating.

  The present invention will be described in more detail with reference to the following 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 have been removed are precisely weighed, and 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) is added. It was dissolved and measured at 30 ° C.

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

(3) Average particle diameter of 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 a Nikkiso Microtrac UPA.

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

(5) Initial adhesiveness An active energy ray-curable resin composition as shown below is dropped on a glass plate, and a polyester film is laminated on the glass plate so that the coating layer and the active energy ray-curable resin composition are in contact with each other. Then, level the thickness after curing with a roller with a load of 4 kg and a width of 50 cm to 15 μm, and then use a high-pressure mercury lamp with an energy of 160 W / cm and irradiate from the film side for about 10 seconds at an irradiation distance of 150 mm. After curing, the film was peeled off from the glass plate to obtain a laminated film having a structure of <polyester film / coating layer / active energy ray curable resin layer>. The active energy ray-curable resin layer of the obtained laminated film was cut into a cross cut so that there were 100 grids in a 1-inch width, and immediately a tape with a width of 24 mm (Cello Tape (registered trademark) CT-24 manufactured by Nichiban Co., Ltd.) Was peeled off rapidly at a peeling angle of 180 °, and then the adhesion was evaluated by the peeling area. The judgment criteria are as follows.
A: Number of cross-cuts = 0
○: 1 ≦ Number of cross cuts ≦ 10
Δ: 11 ≦ number of cross-cuts ≦ 20
×: 21 <Number of cross-cuts peeled ××: Whole surface peeled

  Cured resin composition: 45 parts of NK ester A-LEN-10 (manufactured by Shin-Nakamura Chemical Co., Ltd.), 13 parts of NK ester A-TMPT (manufactured by Shin-Nakamura Chemical Co., Ltd.), New Frontier BPE-4 (Daiichi Kogyo Seiyaku Co., Ltd.) A composition comprising 40 parts of IRGACURE651 (manufactured by Ciba Specialty Chemicals).

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 number average obtained by copolymerizing a constituent unit of the following formula 1-1, a constituent unit of the following formula 1-2, and a constituent unit of the following formula 1-3 in a weight ratio of 80/10/10. A high molecular compound having a molecular weight of 21,000.

(U1): 76.7 parts of a polycarbonate polyol (number average molecular weight of about 1,000 in GCP) obtained by reaction of 1,6-hexanediol with diethyler carbonate, polyethylene glycol (Daiichi Kogyo Seiyaku Co., Ltd., (Trade name PEG600, molecular weight 600) 6.4 parts, trimethylolpropane 2.0 parts, N-methyl-N, N-diethanolamine 19.9 parts, 4,4'-dicyclohexylmethane diisocyanate 86. 7 parts and 87 parts of MEK were placed in a reaction vessel and reacted at 70 to 75 ° C. to obtain a urethane polymer. 16.8 parts of dimethyl sulfate was added to this urethane polymer and reacted at 50 to 60 ° C. to obtain a cationic urethane polymer. An aqueous dispersion of a polyurethane resin is obtained by adding 623 parts of water to this and emulsifying it, and then recovering MEK.

(B1): Hydroxyethyl acrylate unit: dicyclohexylmethane diisocyanate unit: hexamethylene diisocyanate trimer unit: caprolactone unit: ethylene glycol unit: dimethylolpropanoic acid unit = 18: 12: 22: 26: 18: 4 (mol%) A polyurethane resin in which the weight of the carbon-carbon double bond formed from is 2.0% by weight.

(B2): hydroxyethyl acrylate unit: dicyclohexylmethane diisocyanate unit: hexamethylene diisocyanate trimer unit: caprolactone unit: ethylene glycol unit: dimethylolpropanoic acid unit = 6: 10: 20: 38: 22: 4 (mol%) A polyurethane resin in which the weight of the carbon-carbon double bond portion formed from is 0.7% by weight.

(C1): Copolymer-type crosslinking agent aqueous solution of 2-isopropenyl-2-oxazoline and acrylic monomer, oxazoline group amount = 4.5 mmol / g
(C2): polyglycerol polyglycidyl ether (C3): hexamethoxymethylolated melamine (F1) having an imino group / methylol group / methoxy group in a molar ratio of 1.5 / 2 / 2.5: average particle size 0 0.07 μm silica sol aqueous dispersion (S1): Polyethylene oxide addition product to acetylene glycol skeleton

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., and an unstretched polyethylene terephthalate film having a thickness composition ratio of A / B / A = 3/94/3 was prepared. This film was stretched 3.7 times in the longitudinal direction while passing through a heated 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.

Example 1:
A coating solution as shown in Table 1-1 was applied to one side of a uniaxially oriented film obtained in the same process as Comparative Example 1. Next, this film was guided to a tenter stretching machine, and the coating composition was dried using the heat, and the following table was formed on a 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 of the amount shown in 1 and 2 was obtained. The properties of this film are shown in Table 2.

Examples 2-4, Comparative Examples 2-5:
In the same process as in Example 1, the coating solution was changed as shown in Tables 1 and 2, and a coating film was obtained in which the coating layer of the amount 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 film of the present invention can be suitably used as a biaxially stretched polyester film in applications requiring excellent antistatic properties and adhesion to various topcoats.

Claims (2)

A polyurethane resin comprising a compound quaternized tertiary amino groups of the chain extender having a tertiary amino group in the molecule and a polycarbonate polyol as a constituent unit (A), carbon - carbon double bond portion 0. and from 7 to 2.0% by weight and the polyurethane resin containing a polyester polyol Lumpur as component units (B), the cationic polymer antistatic agent (C), and a coating solution containing the oxazoline compound (D) coating A laminated polyester film having a coating layer formed by drying on at least one side. The laminated polyester film according to claim 1, wherein the polyurethane resin (B) contains an acrylate group.