WO2021256224A1 - Multilayer polyester film - Google Patents

Abstract

 The present invention addresses the problem of providing a multilayer polyester film which has a coating layer that has excellent transparency (low haze) and excellent durability, while being suppressed in coating film defects, and which has high adhesiveness that is most suitable in various fields such as optical materials, packages and labels. The present invention is a multilayer polyester film which has a coating film that is formed from a coating liquid containing an aqueous dispersion of a hydrophobic blocked isocyanate compound that is hydrophilized by means of an anionic emulsifying agent, a water-dispersible polyurethane resin having a carboxyl group, and a water-dispersible polyester resin, wherein the separation defects of the coating film is less than 5.0 defects/m².

Description

Laminated polyester film

The present invention relates to a laminated polyester film. More specifically, the present invention relates to a laminated polyester film having easy adhesiveness, which is most suitable for all fields such as optics, packaging, and labels having a coating layer having excellent transparency (low haze), durability, and few coating film defects.

Conventional technology

Thermoplastic resin films, especially polyester films, have excellent mechanical properties, electrical properties, dimensional stability, transparency, chemical resistance, etc., and therefore have excellent properties such as magnetic recording materials, packaging materials, solar cell applications, and flat displays. It is widely used in antireflection films, diffusion sheets, optical films such as prism sheets, and label printing films. However, since the surface of the polyester film is highly crystallinely oriented, it has a drawback of poor adhesion to various paints, resins, and inks in processing for these applications. Therefore, a method is known in which a polyurethane resin or a polyurethane resin and an isocyanate-based cross-linking agent are applied in combination on the surface of a polyester film to provide a coating layer having easy-adhesion performance (see Patent Document 1).

In recent years, the use of water-based (water-based) compositions that do not use organic solvents has been emphasized from the viewpoint of environmental protection against air and wastewater and work safety during manufacturing processes and construction. Therefore, a water-dispersible blocked isocyanate-based cross-linking agent using a blocking agent to suppress the reactivity with water has been proposed (see Patent Document 2).

In these water-dispersible blocked isocyanate-based cross-linking agents, a nonionic or anionic hydrophilic group is introduced into the skeleton in order to develop water dispersibility in the cross-linking agent itself. If the amount of this hydrophilic group introduced is low, the water dispersibility of the cross-linking agent itself is lowered, and as a result, the storage stability of the coating material is deteriorated. Further, when the amount of the hydrophilic group introduced is increased, the amount of blocked isocyanate in the cross-linking agent is relatively reduced, so that the performance such as durability of the coating film is insufficient.

In addition, instead of developing water dispersibility in the cross-linking agent itself, forced water-dispersible blocked isocyanate using an emulsifier or the like is also used, but dispersion stability may occur depending on the combination with other water-based resins or additives. May be a problem.

As a solution for ensuring the dispersion stability of these water-dispersible blocked isocyanate-based cross-linking agents, a mixture of a blocked polyisocyanate component and a neutralized carboxyl group-containing isocyanate group-terminated urethane prepolymer is emulsified in water, and a chain extender is used. Emulsions having a core-shell structure in which a blocked isocyanate compound is used as a core component by performing a chain extension reaction and a polyurethane resin in which a carboxyl group-containing isocyanate group-terminated urethane prepolymer is chain-extended as a shell component have been proposed (Patent Documents). 3). These core-shell structure emulsions improve the dispersion stability of the coating liquid, and when applied to a polyester film substrate or the like and sufficiently cured, good adhesion is exhibited, but when the curing is insufficient. It was found that the coating film had a peeling defect due to contact with a traveling roll or the like. In particular, in an in-line coat film in which a coating layer is provided during the film forming process, a tension control roll is often provided in order to suppress tension fluctuations in the stretching process such as in the width direction after coating and drying. There is a tendency for the coating layer to have frequent peeling defects. In addition, in the entire coating and drying processes, the production line speed is often increased from the viewpoint of energy saving or productivity improvement, so that it is becoming difficult to take the amount of heat and time to sufficiently cure the coating layer. There is a growing concern about the occurrence of such peeling defects.

Japanese Unexamined Patent Publication No. 60-199648 Japanese Unexamined Patent Publication No. 2005-154674 International Publication No. 2009/1132412

The present invention is intended to solve the above-mentioned problems of the polyester film, and is used for optics and packaging, which has a coating layer having excellent transparency (low haze), excellent durability, and few coating film defects. It is intended to provide a laminated polyester film having optimum easy adhesiveness for all fields such as for labels.

That is, the present invention has the following configuration.
1. 1. It has a coating film formed from a coating liquid containing an aqueous dispersion of a hydrophobic block isocyanate compound hydrophilized by an anionic emulsifier, a water-dispersible polyurethane resin having a carboxyl group, and a water-dispersible polyester resin. Laminated polyester film with less than 5.0 pieces / m ^{2 of peeling defects.}
2. 2. The laminated polyester film according to the first item above, wherein the anionic emulsifier that hydrophilizes the aqueous dispersion of the hydrophobic blocked isocyanate compound is an aqueous dispersible polyurethane resin having a carboxyl group.
3. 3. The laminated polyester film according to the first or second above, which has a core-shell structure having a hydrophobic blocked isocyanate compound as a core and a water-dispersible polyurethane resin having a carboxyl group as a shell.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a laminated polyester film having an optimum easy-adhesion property for all fields such as optics, packaging, and labels having a coating layer having excellent transparency (low haze), durability, and few coating film defects. It has become possible.
In particular, the laminated polyester film of the present invention is excellent in adhesiveness to ultraviolet (UV) curable resins such as a hard coat layer, a lens layer, and ink, but is particularly excellent in adhesiveness to a high level of UV ink.

(Polyester film base material)
In the present invention, the polyester resin constituting the polyester film base material includes polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, polytrimethylene terephthalate and the like, as well as the diol component or dicarboxylic acid component of the polyester resin as described above. It is a copolymerized polyester resin in which a part of the above is replaced with the following copolymerization component. For example, as the copolymerization component, a diol component such as diethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, polyalkylene glycol, etc. , Adipic acid, sebatic acid, phthalic acid, isophthalic acid, 5-sodium isophthalic acid, dicarboxylic acid components such as 2,6-naphthalenedicarboxylic acid and the like can be mentioned.

The polyester resin suitably used for the polyester film substrate in the present invention is mainly selected from polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate. Among these polyester resins, polyethylene terephthalate is most preferable from the viewpoint of the balance between physical properties and cost. Further, the polyester film base material composed of these polyester resins is preferably a biaxially stretched polyester film, and can improve chemical resistance, heat resistance, mechanical strength and the like.

The catalyst for polycondensation used in the production of polyester resin is not particularly limited, but antimony trioxide is suitable because it is an inexpensive catalyst and has excellent catalytic activity. It is also preferable to use a germanium compound or a titanium compound. Further preferable polycondensation catalysts include catalysts containing aluminum and / or its compounds and phenolic compounds, catalysts containing aluminum and / or its compounds and phosphorus compounds, and catalysts containing aluminum salts of phosphorus compounds.

Further, the polyester film base material in the present invention is not particularly limited in its layer structure, and may be a single-layer polyester film or a two-layer structure having different components from each other, and the outer layer and the inner layer may be formed. It may be a polyester film base material having at least three layers.

(Coating layer)
The laminated polyester film of the present invention is made of a hydrophobic blocked isocyanate compound, a water-dispersible polyurethane resin having a carboxyl group, and a water-dispersible polyester resin in order to improve the adhesiveness to a hard coat layer, a lens layer, an ink and the like. It is preferable that the formed coating layers are laminated. The coating layer may be provided on both sides of the polyester film, or may be provided on only one side of the polyester film, and a different type of resin coating layer may be provided on the other side.

The coating layer of the present invention is preferably formed mainly from a hydrophobic block isocyanate compound hydrolyzed by an anionic emulsifier, a water-dispersible polyurethane resin having a carboxyl group, and a water-dispersible polyester resin, but the hydrophobic block. The anionic emulsifier that hydrophilizes the isocyanate compound is preferably an water-dispersible polyurethane resin having a carboxyl group, and as a particularly desirable form, a hydrophobic blocked isocyanate compound and a water-dispersible polyurethane resin having a carboxyl group are hydrophobic. It is preferable to have a core-shell structure having a blocked isocyanate compound as a core and a water-dispersible polyurethane resin having a carboxyl group as a shell. The above-mentioned hydrophilization does not mean only complete hydrophilization, but can be said to achieve the purpose if water dispersibility is provided so that an aqueous coating liquid can be prepared.

The water-dispersible polyurethane resin having a hydrophobic blocked isocyanate compound and a carboxyl group preferably has a mass ratio in the range of 5/95 to 80/20, more preferably 10/90 to 70/30, and further 20 /. The range of 80 to 60/40 is preferable. When the total amount of the hydrophobic blocked isocyanate compound and the water-dispersible polyurethane resin having a carboxyl group is 100 parts by mass, it is preferable that the hydrophobic blocked isocyanate compound is 5 parts by mass or more because durability such as moisture resistance is improved. When the total of the hydrophobic block isocyanate compound and the water-dispersible polyurethane resin having a carboxyl group is 100 parts by mass, if the water-dispersible polyurethane resin having a carboxyl group is 20 parts by mass or more, the stability of the coating liquid with time is determined. It is preferable because the transparency (low haze) and the adhesiveness to the hard coat layer, the lens layer, the ink and the like are improved. Further, the total of the above-mentioned hydrophobic block isocyanate compound and the water-dispersible polyurethane resin having a carboxyl group and the polyester resin are preferably in the range of 10/90 to 90/10 as a mass ratio, and more preferably 20/80 to 80/. It is in the range of 20, and more preferably in the range of 30/70 to 70/30. When the total of the above hydrophobic blocked isocyanate compound and the water-dispersible polyurethane resin having a carboxyl group and the total of the polyester resin are 100 parts by mass, the hydrophobic blocked isocyanate compound and the water-dispersible polyurethane resin having a carboxyl group When the total amount is 10 parts by mass or more, the adhesiveness to the hard coat layer, the lens layer, the ink and the like is improved, which is preferable. Further, when the polyester resin is 10 parts by mass or more, it is preferable that the peeling defect of the coating film is easily suppressed.

In the coating film of the present invention, the peeling defect is ^{preferably less than 5.0 pieces / m 2} , more preferably less than 4.0 pieces / m ² , and further preferably less than ^{3.0 pieces / m 2.} be. When the peeling defect is ^{less than 5.0 pieces / m 2} , the yield of the accepted product due to the peeling defect becomes a satisfactory level, which is preferable, especially in optical applications. In order to reduce the peeling defect to less than 5.0 pieces / m ² , an aqueous dispersion of a hydrophobic blocked isocyanate compound in which the coating film is hydrophilized by an anionic emulsifier, an aqueous dispersion polyurethane resin having a carboxyl group, and water It is preferably formed from a coating liquid containing a dispersible polyester resin, and more preferably the ratio of the compound, the resin and the compound as described above. The defect of peeling ^{is most preferably 0 pieces / m 2} , but 0.5 pieces / m ² or more may be used.
Hereinafter, each composition of the coating layer will be described in detail.

(Hydrophobic blocked isocyanate compound)
In the present invention, a hydrophobic blocked isocyanate compound is used. Hydrophobicity means that no hydrophilic group is introduced into the molecule of the blocked isocyanate compound so as to allow self-emulsification or water dispersion of the compound alone. Examples of these hydrophilic groups include a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphonic acid group, a polyoxyethylene group and the like. However, the presence of a small amount of hydrophilic groups is not excluded when the compound is introduced for the purpose of adjusting the physical characteristics of the compound or when it is derived from the synthetic reaction residue of the compound or the impurities of the raw material.
In the present invention, by using a hydrophobic blocked isocyanate compound, moisture resistance such as adhesiveness can be further improved.

Examples of the blocking agent include pyrazole compounds such as 3,5-dimethylpyrazole, 3-methylpyrazole, 4-bromo-3,5-dimethylpyrazole and 4-nitro-3,5-dimethylpyrazole, and phenolic compounds such as phenol and cresol. , An aliphatic alcohol system such as methanol and ethanol, an active methylene system such as dimethyl malonate and acetylacetone, a mercaptan system such as butyl mercaptan and dodecyl mercaptan, an acid amide system such as acetanilide and acetate amide, ε-caprolactam, δ-valerolactam. Lactam-based, succinic acid imide, acid-imide-based such as maleate imide, oxime-based such as acetaldoxime, acetone oxime, and methyl ethyl keto-oxime, and amine-based blocking agents such as diphenylaniline, aniline, and ethyleneimine. Be done. However, a blocking agent in which the reaction product with the isocyanate group becomes a hydrophilic group is not so preferable, and examples thereof include compounds such as sulfites, bicarbonates, and diethanolamine.

The upper limit of the dissociation temperature of the blocking agent is preferably 200 ° C, more preferably 180 ° C, still more preferably 160 ° C, particularly preferably 150 ° C, and most preferably 120 ° C. As for the blocking agent, the blocking agent is dissociated by heat addition in the drying step after the coating liquid is applied or in the case of the in-line coating method in the film forming step, and a regenerated isocyanate group is generated. As a result, the cross-linking reaction with other polyurethane resins and the like in the coating film proceeds, and the cross-linking state of the coating film is improved.

Examples of the blocking agent having a dissociation temperature of 120 ° C. or lower that the hydrophobic blocked isocyanate in the present invention can preferably contain include the above-mentioned pyrazole compounds such as 3,5-dimethylpyrazole and 3-methylpyrazole, and dimethyl malonate. Examples thereof include malonic acid ester compounds such as diethyl malonate, acetone oxime, and methyl ethyl keto oxime. Of these, methyl ethyl ketooxime, malonic acid ester compounds, or pyrazole compounds are preferable from the viewpoint of moisture resistance and heat resistance and yellowing.

The hydrophobic blocked isocyanate is preferably bifunctional or higher, and trifunctional or higher functional blocked isocyanate is more preferable from the viewpoint of crosslinkability of the coating film.

The trifunctional or higher functional polyisocyanate which is a precursor of the hydrophobic blocked isocyanate in the present invention can be suitably obtained by introducing an isocyanate monomer. Examples thereof include a bullet form, an isocyanurate form, and an adduct form obtained by modifying an isocyanate monomer such as an aromatic diisocyanate having two isocyanate groups, an aliphatic diisocyanate, an aromatic aliphatic diisocyanate, or an alicyclic diisocyanate.
The burette body is a self-condensate having a burette bond formed by self-condensation of an isocyanate monomer, and examples thereof include a burette body of hexamethylene diisocyanate.
The isocyanurate form is a trimer of an isocyanate monomer, and examples thereof include a trimer of hexamethylene diisocyanate, a trimer of isophorone diisocyanate, and a trimer of tolylene diisocyanate.
The adduct is a trifunctional or higher functional isocyanate compound obtained by reacting an isocyanate monomer with a trifunctional or higher low molecular weight active hydrogen-containing compound, for example, a compound obtained by reacting trimethylolpropane with hexamethylene diisocyanate. Examples thereof include a compound obtained by reacting trimethylolpropane with tolylene diisocyanate, a compound obtained by reacting trimethylolpropane with xylylene diisocyanate, and a compound obtained by reacting trimethylolpropane with isophorone diisocyanate.

Examples of the isocyanate monomer include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, and 1,5. -Naftylene diisocyanate, 1,4-naphthylene diisocyanate, phenylenedi isocyanate, tetramethylxylylene diisocyanate, 4,4'-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2,2'-diphenylpropane- 4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diphenylpropanediisocyanate, 3,3'-dimethoxydiphenyl-4,4'-diisocyanate, xylylene diisocyanate, etc. Aromatic diisocyanates, isophorone diisocyanates and 4,4-dicyclohexylmethane diisocyanates, alicyclic diisocyanates such as 1,3-bis (isocyanatemethyl) cyclohexane, hexamethylene diisocyanates, and 2,2,4-trimethylhexamethylene diisocyanates. Examples thereof include aliphatic diisocyanates such as. Aliphatic compounds, alicyclic isocyanates, and modified products thereof are preferable from the viewpoints of transparency, yellowing resistance, adhesiveness, and moisture heat resistance.

As described above, the blocked isocyanate compound itself in the present invention is hydrophobic and does not have water dispersibility. Therefore, it is necessary to use an emulsifier or the like separately from the blocked isocyanate compound to develop water dispersibility. As the emulsifier, anionic, cationic, nonionic, amphoteric surfactants and the like can be used, but in this case, it is preferable to use anionic. By using an anionic surfactant, the dispersion stability of the blocked isocyanate compound can be improved. A low molecular weight or high molecular weight type can be used as the anionic surfactant in the present invention.

Low-molecular-weight anionic surfactants include carboxylic acid type, sulfate ester type, sulfonic acid type, and phosphoric acid ester type. For example, examples of the carboxylic acid type include aliphatic monocarboxylates, polyoxyethylene alkyl ether carboxylates, N-acylsulfosin salts and N-acylglutamine salts, and examples of sulfate ester types include alkyl sulfates and polyoxys. Examples of the sulfonic acid type include ethylene alkyl ether sulfate, oil and fat sulfate ester salt, and examples of the sulfonic acid type include dialkyl sulfosuccinate, alkane sulfonate, alpha olefin sulfonate, alkylbenzene sulfonate, alkylnaphthalene sulfonate, and N-acyl. Examples thereof include N-acyltaurine salts, and examples of the phosphate ester type include alkyl phosphates, polyoxyethylene alkyl ether phosphates, and polyoxyethylene alkyl phenyl ether phosphates.

The polymer anionic surfactant includes polymers or copolymers such as acrylic acid, maleic acid and styrene sulfonic acid, which are unsaturated monomers having an anionic group, sulfonic acid groups, carboxylic acids, phosphinic acid and the like. Examples thereof include polyesters and polyurethane resins obtained by copolymerizing the monomers having the same.

In the present invention, it is preferable to use a polyurethane resin having a carboxyl group. More preferably, it has a core-shell structure in which a hydrophobic blocked isocyanate compound is used as a core and a polyurethane resin having a carboxyl group is used as a shell. These make it possible to maintain the long-term dispersion stability of the blocked isocyanate compound, and the dispersion stability is unlikely to decrease even when mixed with other resins or additives. Details of the core-shell structure will be described later.

(Polyurethane resin)
The polyurethane resin in the present invention is preferably a water-dispersible polyurethane resin having at least a polyol component, a polyisocyanate component, and, if necessary, a carboxyl group consisting of a chain extender. The carboxyl group of the polyurethane resin in the present invention is present in the molecule or in the side chain in order to impart water solubility or water dispersibility to the polyurethane resin. The term "in the molecule" as used herein means a substance present in the main chain or at the end of the polyurethane resin. Further, the side chain is introduced onto the branched molecular chain after being synthesized and polymerized due to the presence of three or more terminal functional groups of any of the raw material components constituting the molecular chain. It is a thing. In the present invention, there is no problem even if a hydrophilic group other than the carboxyl group is introduced into the polyurethane resin. As the hydrophilic group other than the carboxyl group, an anionic group typified by sulfonic acid, phosphonic acid, etc., a cationic group typified by a quaternary amine, and a nonionic group typified by an oxyalkylene group may be used. However, a nonionic group typified by an oxyalkylene group is preferable because it is easy to introduce and does not react with a carboxyl group.

The polyurethane resin having a carboxyl group in the present invention is mainly obtained by using a carboxyl group-containing polyol component as a component of the urethane resin. Examples of the carboxyl group-containing polyol component include the following. Those having a relatively high molecular weight, for example, a carboxyl group-containing polyalkylene glycol, a carboxyl group-containing acrylic polyol, a carboxyl group-containing polyolefin polyol, a carboxyl group-containing polyester polyol, and the like can be used. Further, those having a relatively low molecular weight, for example, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolpropane valeric acid and the like can be used. .. In particular, dimethylolpropionic acid and dimethylolbutanoic acid are preferably used for introducing a carboxyl group.

The polyurethane resin having a carboxyl group preferably has an acid value of 10 to 60 mgKOH / g, and more preferably an acid value of 20 to 50 mgKOH / g. When the acid value is 10 mgKOH / g or more, the hydrophilicity of the polyurethane resin itself is improved, and water solubility or water dispersibility is maintained, which is preferable. When the acid value is 60 mgKOH / g or less, the water resistance of the coating layer is improved and there is no blocking problem due to moisture absorption, which is preferable. However, in the polyurethane resin having a carboxyl group in the present invention, in order to supplement the water solubility or water dispersibility of the polyurethane resin, hydrophilic groups other than the carboxyl group, such as hydroxyl groups, oxyalkyl groups, sulfonic acids and phosphonic acids, are used. A quaternary amine or the like may be introduced within a range in which the performance does not deteriorate.

The carboxyl group in the polyurethane resin may be neutralized with a basic compound. Examples of the basic compound used for neutralization include alkali metals such as sodium and potassium, alkaline earth metals such as magnesium and calcium, and organic amine compounds. Among these, an organic amine compound that easily dissociates from a carboxyl group by heating is preferable. Examples of the organic amine compound include ammonia, methylamine, ethylamine, propylamine, isopropylamine, butylamine, 2-ethylhexylamine, cyclohexylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, trimethylamine and triethylamine. Linear and branched 1,2 or tertiary amines with 1 to 20 carbon atoms such as triisopropylamine, tributylamine and ethylenediamine, cyclic amines such as morpholin, N-alkylmorpholin and pyridine, monoisopropanolamine and methylethanol. Examples thereof include hydroxyl group-containing amines such as amines, methylisopropanolamines, dimethylethanolamines, diisopropanolamines, diethanolamines, triethanolamines, diethylethanolamines and triethanolamines.

It is preferable to use a polyester polyol or a polycarbonate polyol in addition to the above-mentioned polyoxyalkylene glycol as the main polyol component used for synthesizing and polymerizing the urethane resin having a carboxyl group in the present invention.

The number average molecular weight of the polyester polyol or the polycarbonate polyol in the present invention is preferably 300 to 5000. It is more preferably 400 to 4000, and most preferably 500 to 3000. When it is 300 or more, the adhesiveness can be improved, which is preferable. When it is 5000 or less, fusion between the coating layers can be prevented (blocking resistance is improved), which is preferable.

The polyester polyol in the present invention is preferably an aliphatic or alicyclic group. Therefore, the dicarboxylic acid components of the polyester polyol include aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. Can be mentioned. The diol component includes ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol. , 1,7-Heptanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, neopentyl glycol and other aliphatic diols, cyclohexanedimethanol and other fats Examples include cyclic diols. Of these, in the present invention, it is preferable to mainly use a long-chain fatty acid of adipic acid or higher and a long-chain diol of pentanediol or higher. However, a trifunctional or higher functional polycarboxylic acid, polyol, unsaturated type, or aromatic component may be used as long as the physical properties are not deteriorated.

As the polycarbonate polyol in the present invention, it is preferable to use an aliphatic polycarbonate polyol. Examples of the aliphatic polycarbonate polyol include an aliphatic polycarbonate diol and an aliphatic polycarbonate triol, and an aliphatic polycarbonate diol can be preferably used. Examples of the aliphatic polycarbonate diol used for synthesizing and polymerizing the urethane resin having a polycarbonate structure in the present invention include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,5. -Pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 1,8-nonanediol, neopentyl glycol, diethylene glycol, dipropylene glycol and other diols Examples thereof include aliphatic polycarbonate diols obtained by reacting one or more of them with carbonates such as dimethyl carbonate, ethylene carbonate and phosgene.

In order to synthesize and polymerize the urethane resin in the present invention, other polyol components other than the above can also be used. Examples of other polyol components include polyether polyols, polyolefin polyols, dimer polyols, silicone polyols and the like.

Examples of the polyisocyanate used for the synthesis and polymerization of the water-dispersible urethane resin having a carboxyl group in the present invention include aromatic diisocyanates containing an aromatic ring such as xylylene diisocyanate, isophorone diisocyanate and 4,4-dicyclohexylmethane diisocyanate. , 1,3-Bis (isocyanatemethyl) cyclohexane and other alicyclic diisocyanates, hexamethylene diisocyanate, and 2,2,4-trimethylhexamethylene diisocyanate and other aliphatic diisocyanates, or isocyanates produced from diisocyanates. Examples thereof include modified polyisocyanates containing a nurate bond, a biurette bond or an allophanate bond, and polyisocyanates in which a single or a plurality of diisocyanates are previously added to trimethylol propane or the like. When alicyclic diisocyanates or aliphatic diisocyanates are used rather than the aromatic diisocyanates containing the aromatic ring, the problem of yellowing is less likely to occur, which is preferable.

Examples of the chain extender include glycols such as ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol and 1,6-hexanediol, polyhydric alcohols such as glycerin, trimethylolpropane, and pentaerythritol, and ethylenediamine. , Hexamethylenediamine, diamines such as piperazine, aminoalcohols such as monoethanolamine and diethanolamine, thioglycols such as thiodiethyleneglycol, and water. Further, if the amount is small, a polyol having three or more functional groups, a polyamine, or the like may be used.

There are no particular restrictions on the polymerization method of the polyurethane resin having a carboxyl group, and a solvent may be used or a solvent may be used. In the present invention, the solvent system is preferable from the viewpoint of using it as an emulsifier for the above-mentioned hydrophobic blocked isocyanate compound. Although the solvent may remain in the aqueous dispersion or the solvent may be removed, it is preferable to remove the solvent from the viewpoint of the environment.

The method for producing a dispersion of a blocked isocyanate compound using a water-dispersible polyurethane resin having a carboxyl group as an emulsifier is not particularly limited, but water dispersion is carried out after mixing the hydrophobic blocked isocyanate compound and the polyurethane resin having a carboxyl group. It is preferable to do so from the viewpoint of dispersion stability of the blocked isocyanate compound. In particular, at the stage of polyurethane prepolymer, a blocked isocyanate compound is used as a core and polyurethane resin, such that it is mixed with a blocked isocyanate compound, water-dispersed, and then polyamine or the like is added to form a chain extender in a water-dispersed state to form a polyurethane resin. An aqueous dispersion having a core-shell structure having a shell is preferable.

The water-dispersible polyurethane resin having a carboxyl group in the present invention may have a reactive group such as blocked isocyanate at the terminal or side chain in order to improve the hardness.

(Polyester resin)
The polyester resin used in combination with the coating layer in the present invention is not particularly limited, but a polyester resin containing 50 mol% or more of the aromatic dicarboxylic acid in the acid component is preferable from the viewpoint of hydrolysis resistance and physical characteristics. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid and the like. Other acid components include aliphatic dicarboxylic acids such as adipic acid and sebacic acid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, acid anhydrides such as maleic anhydride, or trimellitic acid and trimesin, as required. A tricarboxylic acid such as an acid can be used. As the diol component, it is preferable that ethylene glycol is contained in an amount of 30 mol% or more in the diol component. Other diol components include linear aliphatic diols such as 1,3-propanediol, 1,4-butanediol and 1,6-hexanediol, or 1,2-propanezyl and 1,3-butane. Diol, branched aliphatic diols such as 2,2-dimethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, alicyclic diols such as cyclohexanedimethanol, diethylene glycol, dipropylene glycol and the like. Examples thereof include polyoxyalkylene glycols such as diglycol and polyethylene glycol, and polyoxyalkylene glycol derivatives such as bisphenol A.

It is preferable that a hydrophilic group is present on the molecular skeleton in order to impart water dispersibility to the polyester resin. As the hydrophilic group, a dicarboxylic acid in which a phosphonic acid group, a sulfonic acid group or the like is introduced into a dicarboxylic acid component may be used, or a polyether such as polyethylene glycol may be used as a diol component. Further, the carboxyl group may be introduced into the polyester skeleton by reacting the hydroxyl group terminal of the polymerized polyester with the polycarboxylic acid anhydride. In the present invention, it is preferable to use a sulfonic acid group as the hydrophilic group from the viewpoint of dispersion stability. It is preferable to polymerize the sulfonic acid group-containing dicarboxylic acid in the dicarboxylic acid component in the range of 1 to 10 mol%, and examples of the sulfonic acid group-containing dicarboxylic acid include sulfoterephthalic acid, 5-sulfoisophthalic acid, and 5-sodium sulfoisophthalic acid. Acids and the like can be mentioned.

Further, in the present invention, it may be used in combination with other resins as long as the performance is not affected. Examples of the resin to be used in combination include a non-carboxyl group-containing polyurethane resin, an alkyd resin, an acrylic resin, a cellulose resin, a polyolefin resin, and a polyacetal resin.

A cross-linking agent other than the hydrophobic blocked isocyanate compound in the present invention may be used in combination. As other cross-linking agents, hydrophilic blocked isocyanate-based, epoxy-based, melamine-based, oxazoline-based, carbodiimide-based and the like can be used. By appropriately using another cross-linking agent in the range of 20% by mass or less, the cross-linking state can be adjusted to reduce the influence on the adhesiveness and the like, and the durability such as moisture and heat resistance can be further improved. Further, when a hydrophilic blocked isocyanate system is used as the cross-linking agent, the hydrophobic blocked isocyanate compound can adjust the cross-linking state by changing the cross-linking reaction start temperature depending on the composition of the blocking agent. It is preferable to select different blocking agents.

(Additive)
In the coating layer in the present invention, known additives such as surfactants, antioxidants, heat-resistant stabilizers, weather-resistant stabilizers, ultraviolet absorbers, organic lubricants, and pigments are used as long as the effects of the present invention are not impaired. , Dyes, organic or inorganic particles, antistatic agents, nucleating agents and the like may be added.

In the present invention, it is also a preferred embodiment to add particles other than those described above to the coating layer in order to further improve the blocking resistance of the coating layer. In the present invention, the particles contained in the coating layer include, for example, titanium oxide, barium sulfate, calcium carbonate, calcium sulfate, silica, alumina, talc, kaolin, clay and the like, or a mixture thereof, and other general ones. Inorganic particles such as calcium phosphate, mica, hectrite, zirconia, tungsten oxide, lithium fluoride, calcium fluoride and others, and organic particles such as styrene, acrylic, melamine, benzoguanamine and silicone. Examples include polymer particles.

The average particle size of the other particles in the coating layer (average particle size based on the number of particles by a scanning electron microscope (SEM); the same applies hereinafter) is preferably 0.02 to 2.00 μm, more preferably 0.04 to 1. It is 0.00 μm. When the average particle size of the inert particles is 0.04 μm or more, it becomes easy to form irregularities on the film surface, so that the handleability such as slipperiness and winding property of the film is further improved, and the film is bonded. The workability of the above is good and is preferable. On the other hand, when the average particle size of the inert particles is 2.00 μm or less, the particles are less likely to fall off, which is preferable. The particle concentration in the coating layer is preferably 1 to 20% by mass in the solid component.

The average particle size of the other particles was measured by observing the particles in the cross section of the laminated polyester film with a scanning electron microscope, observing 30 particles, and using the average value as the average particle size.

The shape of the other particles is not particularly limited as long as it satisfies the object of the present invention, and spherical particles and amorphous non-spherical particles can be used. The particle size of the amorphous particles can be calculated as the equivalent circle diameter. The equivalent circle diameter is a value obtained by dividing the observed particle area by π, calculating the square root, and doubling it.

(Manufacturing of laminated polyester film)
The method for producing a laminated polyester film of the present invention will be described with reference to an example in which a coating layer is provided during a film forming process using a polyethylene terephthalate (hereinafter, may be abbreviated as PET) film base material. Not limited to.

After the PET resin is sufficiently vacuum-dried, it is supplied to an extruder, and the molten PET resin at about 280 ° C. is melt-extruded into a sheet on a rotary cooling roll, cooled and solidified by an electrostatic application method, and unstretched PET. Get a sheet. The unstretched PET sheet may have a single-layer structure or a multi-layer structure by a coextrusion method.

The obtained unstretched PET sheet is uniaxially stretched or biaxially stretched to orient the crystals. For example, in the case of biaxial stretching, a roll heated to 80 to 120 ° C. is stretched 3.0 to 5.0 times in the longitudinal direction to obtain a uniaxially stretched PET film, and then the end of the film is gripped with a clip. Then, it is guided to a hot air zone heated to 80 to 180 ° C. and stretched 3.0 to 5.0 times in the width direction. In the case of uniaxial stretching, the unstretched PET sheet is stretched 3.0 to 5.0 times in the tenter. After stretching, the crystals are continuously led to a heat treatment zone at 180 to 230 ° C. and heat-treated to complete the crystal orientation.

Any known method can be used as the method for applying the coating liquid to the PET film. For example, reverse roll coat method, gravure coat method, kiss coat method, die coater method, roll brush method, spray coat method, air knife coat method, wire bar coat method, pipe doctor method, impregnation coat method, curtain coat method, etc. Be done. These methods can be applied alone or in combination.

In the present invention, the thickness of the coating layer can be appropriately set in the range of 0.001 to 2.00 μm, but the range of 0.01 to 1.00 μm is preferable in order to achieve both workability and adhesiveness. It is more preferably 0.02 to 0.80 μm, and even more preferably 0.05 to 0.50 μm. When the thickness of the coating layer is 0.001 μm or more, the adhesiveness is good and it is preferable. When the thickness of the coating layer is 2.00 μm or less, blocking is less likely to occur, which is preferable.

The upper limit of the haze of the laminated polyester film of the present invention is preferably 2.0%, more preferably 1.8%, still more preferably 1.5%, and particularly preferably 1.2%. When the haze is 2.0% or less, it is preferable in terms of transparency, and it can be suitably used for optical film applications where transparency is required. The haze is preferably small, but may be 0.1% or more, or 0.3% or more.

Next, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. First, the evaluation method used in the present invention will be described below.

(1) Method for detecting peeling defects A sample film roll having a width of 1 m and a length of 10 m taken out from the product film rolls obtained in Examples and Comparative Examples was vertically hung in a dark room. Next, a matte black cloth is placed on the entire back surface of the film, and an LED light (1000 lumens) is used from the front surface (coating layer surface) to unwind the laminated film in the range of about 10 ° to 45 ° with respect to the film surface. Observe from the front of the film while changing the angle of the light, and detect defects with a major axis of 100 μm or more visually or using a scaled loupe (SCALE LUPE × 10 manufactured by PEAK) with a magnification of 10 times ^{for an evaluation area of 10 m 2.} Marking was done.

(2) Defect determination method for peeling The defect portion marked by the above method was cut out and measured under the following conditions using a non-contact surface shape measurement system (VertScan R550H-M100 manufactured by Ryoka System Co., Ltd.).
(Measurement condition)
・ Measurement mode: WAVE mode ・ Objective lens: 10x ・ 0.5 × Tube lens ・ Measurement area 936μm × 702μm
(Analysis conditions)
・ Surface correction: 4th correction The measured defects are the following criteria a. ~ E. Those that satisfy all of the above were judged to be the defects of peeling.
The numerical value in the depth direction of the defect was obtained by performing cross-sectional analysis of the above measurement data.
Ah. Those observed to be surrounded by a closed curve that does not intersect with themselves, and those surrounded by a maximum width of 200 μm or more a. The inside of a closed curve is a recess c. The maximum depth of the outer peripheral part and the inner part of the closed curve is 70% or more of the coating layer thickness.
Workman. The depth variation of the internal region of the closed curve is in the range of less than 50% of the coating layer thickness.
E. 50% or more of the closed curve has a gradient of 60 ° or more from the horizontal plane inside the curve. The number of peeling defects determined above was converted per ^{1 m 2.} For the above-mentioned coating film thickness, it is possible to use a value calculated from the total solid content concentration of the coating liquid, a resin content specific gravity, a coating amount, a draw ratio, etc., or an analysis value from an SEM photograph of a film cross section.

(3) Haze The haze of the obtained laminated polyester film was measured using a turbidity meter (NDH5000, manufactured by Nippon Denshoku) in accordance with JIS K 7136: 2000.

(4) Blocking resistance Two film samples were superposed so that the coated layer surfaces faced each other, a load of 98 kPa was applied, and the two film samples were brought into close contact with each other for 24 hours in an atmosphere of 50 ° C. and left to stand. Then, the film was peeled off, and the peeled state was judged according to the following criteria.
◯: The coating layer does not transfer and can be peeled off lightly.
Δ: The coating layer is maintained, but the surface layer of the coating layer is partially transferred to the mating surface.
X: Two films are stuck and cannot be peeled off, or even if they can be peeled off, the film base material is cleaved.

(5) Adhesion with UV ink A UV ink [manufactured by T & K TOKA Co., Ltd., trade name "BEST CURE UV161 indigo S" or "BEST CURE UV161 white S"] is used on the coating layer of the laminated polyester film. Printing was performed with an ink pipette 4 scales and a 2-split roll using a printing machine [manufactured by Ming Seisakusho Co., Ltd., trade name "RI tester"], and then 100 mJ / cm ^{2 using a high-pressure mercury lamp on the film coated with the ink layer.} The UV curable ink was cured by irradiating with the ultraviolet rays of. Next, using a cutter guide with a gap spacing of 2 mm, 100 grid-like cuts that penetrate the ink layer and reach the film substrate are made on the ink layer surface. Next, a cellophane adhesive tape (manufactured by Nichiban, No. 405; 24 mm width) is attached to the cut surface in the shape of a grid. After that, the cellophane adhesive tape is vertically peeled off from the ink layer surface of the ink laminated film, the number of squares peeled off from the ink layer surface of the ink laminated film is visually counted, and the ink layer and the film substrate adhere to each other from the following formula. Seeking sex. In addition, those that were partially peeled out among the squares were also counted as the peeled squares, and the ink adhesion was obtained as shown in the following formula.
Ink adhesion (%) = 100- (number of peeled squares)
Ink adhesion (%) was classified as follows, and ◎ and 〇 were regarded as acceptable.
⊚: 100%, ○: 99-96%, Δ: 95-80%, ×: 79-0%

(6) Adhesion to the hard coat layer Opstar Z7503 (manufactured by Arakawa Chemical Industry Co., Ltd.), which is a UV curable hard coat agent, is applied onto the coated layer of the laminated polyester film using a # 5 wire bar, and 80 It was dried at ° C for 1 minute. ^{Next, the applied film was irradiated with ultraviolet rays of 100 mj / cm 2} using a high-pressure mercury lamp to obtain a hard-coated film. Next, using a cutter guide with a gap spacing of 2 mm, 100 grid-like cuts that penetrate the hardcourt layer and reach the film substrate are made on the hardcourt layer surface. Next, a cellophane adhesive tape (manufactured by Nichiban, No. 405; 24 mm width) is attached to the cut surface in the shape of a grid, and rubbed with an eraser to completely adhere. After that, the cellophane adhesive tape is vertically peeled off from the hard coat layer surface of the hard coat laminated film, and the number of squares peeled off from the hard coat layer surface of the hard coat laminated film is visually counted, and the hard coat layer and the film are counted from the following formula. Obtaining adhesion to the base material. In addition, those that were partially peeled out among the squares were also counted as the peeled squares, and the hard coat adhesion was obtained as shown in the following formula. The hard coat adhesion was 100 (%).
Hardcourt adhesion (%) = 100- (number of peeled squares)
Hardcourt adhesion (%) was classified as follows, and ◎ and 〇 were judged as acceptable.
⊚: 100%, ○: 99-96%, Δ: 95-80%, ×: 79-0%

(7) Moisture and heat resistance A UV ink-coated or hard-coated film prepared in the same manner as in (5) and (6) above is placed in an environment of 80 ° C. and 80% RH so that the coated surface is vertical and another film is applied to the coated surface. It was left for 500 hours without any contact. After the treatment, it was left in an environment of 23 ° C. and 65% RH for 10 minutes without contact with other films or the like on the coated surface. Immediately after the lapse of time, the adhesion of the coated surface was evaluated in the same manner as described above.

Hereinafter, various resins and the like used in the coating liquid used in the present invention will be described.

(Blocked Isocyanate Compound) [BI-1] to [BI-6]
[Synthesis of blocked isocyanate compound BI-1]
In a flask equipped with a stirrer, a thermometer, and a reflux cooling tube, 514.1 parts by mass of isocyanurate trimeride (isocyanate content 21.8%) of hexamethylene diisocyanate and 235.9 parts by mass of 2-butanone oxime and methyl ethyl ketone as a solvent. 250 parts by mass were charged, and the mixture was stirred and reacted at 80 ° C. for 5 hours under a nitrogen atmosphere. After that, the infrared spectrum of the reaction solution was measured, and it was confirmed that the absorption of the isocyanate group disappeared. As a result, a methyl ethyl ketone solution of the blocked isocyanate compound BI-1 was obtained.

[Synthesis of blocked isocyanate compound BI-2]
Hexamethylene diisocyanate isocyanurate trimeride (isocyanate content 21.8%) 506.4 parts by mass, 2-butanone oxime 230.9 mass, number average molecular weight 2000 in a flask equipped with a stirrer, a thermometer, and a reflux cooling tube. 12.7 parts by mass of polytetramethylene glycol and 250 parts by mass of methyl ethyl ketone as a solvent were charged, and the mixture was stirred and reacted at 80 ° C. for 5 hours under a nitrogen atmosphere. After that, the infrared spectrum of the reaction solution was measured, and it was confirmed that the absorption of the isocyanate group disappeared. As a result, a methyl ethyl ketone solution of the blocked isocyanate compound BI-2 was obtained.

[Synthesis of blocked isocyanate compound BI-3]
Polyisocyanate having a biuret structure obtained from hexamethylene diisocyanate in a flask equipped with a stirrer, a thermometer, and a reflux cooling tube ((isocyanate content 23.5%) 495.6 parts by mass, number average molecular weight 400 polypropylene glycol 14. 6 parts by mass and 250 parts by mass of methyl ethyl ketone as a solvent were charged, stirred at 80 ° C. for 2 hours under a nitrogen atmosphere, 2-butanone oxime 239.8 mass was added, and the mixture was further stirred at 80 ° C. for 5 hours to react. After that, the infrared spectrum of the reaction solution was measured, and it was confirmed that the absorption of the isocyanate group had disappeared. As a result, a methyl ethyl ketone solution of the blocked isocyanate compound BI-3 was obtained.

[Synthesis of blocked isocyanate compound BI-4]
A flask equipped with a stirrer, a thermometer, and a reflux condenser is charged with 402.09 parts by mass of isophorone diisocyanate, 347.89 parts by mass of 3,5-dimethylpyrazole, and 250 parts by mass of methyl ethyl ketone as a solvent at 80 ° C. under a nitrogen atmosphere. The mixture was stirred for 5 hours and reacted. After that, the infrared spectrum of the reaction solution was measured, and it was confirmed that the absorption of the isocyanate group disappeared. As a result, a methyl ethyl ketone solution of the blocked isocyanate compound BI-4 was obtained.

[Synthesis of blocked isocyanate compound BI-5]
In a flask equipped with a stirrer, a thermometer, and a reflux cooling tube, an isocyanurate trimerid of hexamethylene diisocyanate (isocyanate content 21.8%) 474.0 parts by mass, hydroxyl value 81 mg KOH / g methoxy 78 parts by mass of polyethylene glycol, 0.003 parts by mass of dioctyltin laurate as a urethanization catalyst and 250 parts by mass of methyl ethyl ketone as a solvent were charged, and after stirring at 85 ° C. for 3 hours under a nitrogen atmosphere, 2-butanone oxime 198.0 mass was added. In addition, the reaction was further stirred at 80 ° C. for 2 hours. After that, the infrared spectrum of the reaction solution was measured, and it was confirmed that the absorption of the isocyanate group disappeared. As a result, a methyl ethyl ketone solution of the blocked isocyanate compound BI-5 having a nonionic group was obtained.

[Synthesis of blocked isocyanate compound BI-6]
In a flask equipped with a stirrer, a thermometer, and a reflux cooling tube, 495.5 parts by mass of isocyanurate trimeride of hexamethylene diisocyanate (isocyanate content 21.8%), 57.5 parts by mass of dimethylol propionic acid, and methyl ethyl ketone as a solvent. 250 parts by mass was charged, and the mixture was stirred at 85 ° C. for 3 hours under a nitrogen atmosphere, 152.4 mass of 2-butanone oxime was added, and the mixture was further stirred at 80 ° C. for 2 hours for reaction. After that, the infrared spectrum of the reaction solution was measured, and it was confirmed that the absorption of the isocyanate group disappeared. As a result, a methyl ethyl ketone solution of the blocked isocyanate compound BI-6 having an anionic group was obtained.

(Aqueous dispersion of blocked isocyanate compound)
[Preparation of BI-1WD, BI-5WD, BI-6WD]
[Manufacture of Water Dispersion A (BI-1WD-A) of Blocked Isocyanate Compound BI-1]
To 100 parts by mass of the methyl ethyl ketone solution of the blocked isocyanate compound BI-1, 15 parts by mass of the anionic surfactant Perex SS-H (Kao Corporation) having a solid content concentration of 50% by mass was added, and 225 parts by mass of water was added with stirring. Added gradually. An aqueous dispersion of the blocked isocyanate compound BI-1 emulsified with an anionic surfactant having a solid content of 25% by mass by removing the methyl ethyl ketone under reduced pressure of this solution under the condition of 50 ° C. or lower and adjusting the concentration with water. A (BI-1WD-A) was obtained.

[Production of Aqueous Dispersion B (BI-1WD-B) of Blocked Isocyanate Compound BI-1]
To 100 parts by mass of the methyl ethyl ketone solution of the blocked isocyanate compound BI-1, 7.5 parts by mass of the nonionic surfactant Emulgen 430 (Kao Corporation) having a solid content concentration of 100% by mass was added, and 225 parts by mass of water was added while stirring. Added gradually. An aqueous dispersion of the blocked isocyanate compound BI-1 emulsified with a nonionic surfactant having a solid content of 25% by mass by removing the methyl ethyl ketone under reduced pressure of this solution at 50 ° C. or lower and adjusting the concentration with water. B (BI-1WD-B) was obtained.

[Production of an aqueous dispersion (BI-5WD) of the blocked isocyanate compound BI-5]
225 parts by mass of water was gradually added to 100 parts by mass of a methyl ethyl ketone solution of the blocked isocyanate compound BI-5 with stirring. Methyl ethyl ketone was removed from this solution under reduced pressure under the condition of 50 ° C. or lower, and the concentration was adjusted with water to carry out an aqueous dispersion (BI-5WD) of a self-emulsifying nonionic blocked isocyanate compound BI-5 having a solid content of 25% by mass. ) Was obtained.

Preparation of Aqueous Dispersion (BI-6WD) of Blocked Isocyanate Compound BI-6 225 parts by mass of water was gradually added to 100 parts by mass of a methyl ethyl ketone solution of blocked isocyanate compound BI-6 with stirring. Under reduced pressure of this solution, methyl ethyl ketone was removed under the condition of 50 ° C. or lower, and the concentration was adjusted with water to carry out an aqueous dispersion (BI-6WD) of a self-emulsifying anionic blocked isocyanate compound BI-6 having a solid content of 25% by mass. ) Was obtained.

(Prepolymer) [P-1] to [P-4]
[Synthesis of prepolymer P-1]
In a flask equipped with a stirrer, a thermometer, and a reflux cooling tube, 498.5 parts by mass of a polycarbonate diol having a number average molecular weight of 2000, 154.3 parts by mass of (cyclohexane-1,2-diylbismethylene) diisosianate, dimethylolpropion. A prepolymer P-1 solution having an anionic carboxyl group having a solid content of 73.7% by mass was prepared by charging 48.7 parts by mass of an acid and 250 parts by mass of a methyl ethyl ketone as a solvent and stirring at 80 ° C. for 5 hours to react. Manufactured.

[Synthesis of prepolymer P-2]
In a flask equipped with a stirrer, a thermometer, and a reflux cooling tube, 369.9 parts by mass of a polycarbonate diol having a number average molecular weight of 2000, 266.4 parts by mass of dicyclohexylmethane-4,4'-diisocyanate, and 59.6 parts by mass of dimethylolpropionic acid. 9.2 parts by mass of methyl ethyl ketooxime, 250 parts by mass of methyl ethyl ketone as a solvent, and 9.2 parts by mass of methyl ethyl ketooxime were charged and stirred at 80 ° C. for 5 hours to react, and the solid content was 73.8% by mass of anionic. A prepolymer P-1 solution having a carboxyl group was produced.

[Synthesis of prepolymer P-3]
Obtained from a mixed dicarboxylic acid of ethylene glycol / neopentyl glycol = 1/1 (molar ratio) and terephthalic acid / isophthalic acid = 1/1 (molar ratio) in a flask equipped with a stirrer, thermometer and reflux cooling tube. 293.4 parts by mass of polyester diol having a number average molecular weight of 500, 322.2 parts by mass of dicyclohexylmethane-4,4'-diisocyanate, 85.0 parts by mass of dimethylolbutanoic acid, and 250 parts by mass of methyl ethyl ketone as a solvent were charged at 80 ° C. The mixture was stirred and reacted for 5 hours to prepare a prepolymer P-3 solution having an anionic carboxyl group having a solid content of 73.7% by mass.

[Synthesis of prepolymer P-4]
486.5 parts by mass of polyethylene glycol with a number average molecular weight of 2000, 157.3 parts by mass of (cyclohexane-1,2-diylbismethylene) diisosianate, 1,6 in a flask equipped with a stirrer, a thermometer, and a reflux cooling tube. -A hexanediol (50.2 parts by mass) and a methyl ethyl ketone (250 parts by mass) as a solvent were charged and reacted at 80 ° C. for 5 hours to prepare a nonionic prepolymer P-4 solution having a solid content of 73.5% by mass. ..

(Core-shell type water-based polyurethane resin) [CS-1] to [CS-6]
[Manufacturing of core-shell type water-based polyurethane resin CS-1]
In a flask equipped with a stirrer, a thermometer and a reflux cooling tube, 66.20 parts by mass of a prepolymer P-1 solution having an anionic carboxyl group, 2.11 parts by mass of triethylamine and a methyl ethyl ketone solution of a blocked isocyanate compound BI-1. 30 parts by mass was charged and stirred for 5 minutes to obtain a mixture. To a flask equipped with a stirrer and a thermometer, 150 g of water and 0.02 g of defoaming agent were added, and the mixture was added over 2 minutes while stirring at 40 ° C., and further stirred at 40 ° C. for 30 minutes. .. Then, 0.250 parts by mass of a 25% by mass ethylenediamine aqueous solution was added, and the mixture was stirred at 40 ° C. for 1 hour, and then the infrared spectrum of the reaction solution was measured to confirm that the absorption of isocyanate groups had disappeared. The ethylmethylketone solvent was removed under reduced pressure conditions, and the concentration was adjusted with water to obtain an aqueous dispersion (CS-1WD) of a core-shell type aqueous polyurethane resin CS-1 having a solid content concentration of 30% by mass. .. This polyurethane resin CS-1 is a polyurethane in which the core is a blocked isocyanate compound BI-1 and the shell is formed from an anionic prepolymer P-1.

[Manufacturing of core-shell type water-based polyurethane resin CS-2]
In a flask equipped with a stirrer, a thermometer, and a reflux cooling tube, 57.31 parts by mass of a prepolymer P-2 solution having an anionic carboxyl group, 2.69 parts by mass of triethylamine, and a methyl ethyl ketone of the blocked isocyanate compound BI-2. 40 parts by mass of the solution was charged and stirred for 5 minutes to obtain a mixture. To a flask equipped with a stirrer and a thermometer, 150 g of water and 0.02 g of defoaming agent were added, and the mixture was added over 2 minutes while stirring at 40 ° C., and further stirred at 40 ° C. for 30 minutes. .. After adding 0.180 parts by mass of a 25% by mass ethylenediamine aqueous solution and stirring at 40 ° C. for 1 hour, the infrared spectrum of the reaction solution was measured, and it was confirmed that the absorption of isocyanate groups disappeared. The ethylmethylketone solvent was removed under reduced pressure conditions, and the concentration was adjusted with water to obtain an aqueous dispersion (CS-2WD) of a core-shell type aqueous polyurethane resin CS-2 having a solid content concentration of 30% by mass. .. This polyurethane resin CS-2 is a polyurethane in which the core is a blocked isocyanate compound BI-2 and the shell is formed from an anionic prepolymer P-2.

[Manufacturing of core-shell type water-based polyurethane resin CS-3]
In a flask equipped with a stirrer, a thermometer and a reflux cooling tube, a methyl ethyl ketone solution of 75.00 parts by mass of a prepolymer P-3 solution having an anionic carboxyl group, 3.64 parts by mass of triethylamine and a blocked isocyanate compound BI-3. 20 parts by mass was charged and stirred for 5 minutes to obtain a mixture. Separately, 150 g of water and 0.02 g of defoaming agent are added to a flask equipped with a stirrer and a thermometer, and the mixture is added over 2 minutes while stirring at 40 ° C., and further at 40 ° C. for 30 minutes. Stirred. Then, 0.140 parts by mass of a 25% by mass ethylenediamine aqueous solution was added, and the mixture was stirred at 40 ° C. for 1 hour, and then the infrared spectrum of the reaction solution was measured to confirm that the absorption of isocyanate groups had disappeared. The ethylmethylketone solvent was removed under reduced pressure conditions, and the concentration was adjusted with water to obtain an aqueous dispersion (CS-3WD) of a core-shell type aqueous polyurethane resin CS-3 having a solid content concentration of 30% by mass. .. This polyurethane resin CS-3 is a polyurethane in which the core is a blocked isocyanate compound BI-3 and the shell is formed from an anionic prepolymer P-3.

[Manufacturing of core-shell type water-based polyurethane resin CS-4]
In a flask equipped with a stirrer, a thermometer and a reflux cooling tube, 66.20 parts by mass of a prepolymer P-1 solution having an anionic carboxyl group, 2.11 parts by mass of triethylamine and a methyl ethyl ketone solution of a blocked isocyanate compound BI-4. 30 parts by mass was charged and stirred for 5 minutes to obtain a mixture. Separately, 150 g of water and 0.02 g of defoaming agent are added to a flask equipped with a stirrer and a thermometer, and the mixture is added over 2 minutes while stirring at 40 ° C., and further, 30 at 40 ° C. The mixture was stirred for a minute. Then, 0.250 parts by mass of a 25% by mass ethylenediamine aqueous solution was added, and the mixture was stirred at 40 ° C. for 1 hour, and then the infrared spectrum of the reaction solution was measured to confirm that the absorption of isocyanate groups had disappeared. Further, by removing the ethylmethylketone solvent under reduced pressure conditions and adjusting the concentration with water, an aqueous dispersion (CS-4WD) of a core-shell type aqueous polyurethane resin CS-4 having a solid content concentration of 30% by mass was prepared. Obtained. This polyurethane resin CS-4 is a polyurethane in which the core is a blocked isocyanate compound BI-4 and the shell is formed from an anionic prepolymer P-1.

[Manufacturing of core-shell type water-based polyurethane resin CS-5]
In a flask equipped with a stirrer, a thermometer and a reflux cooling tube, 66.20 parts by mass of a nonionic prepolymer P-4 solution and 30 parts by mass of a methyl ethyl ketone solution of the blocked isocyanate compound BI-1 were charged and stirred for 5 minutes. The mixture was obtained. Separately, 150 g of water and 0.02 g of defoaming agent are added to a flask equipped with a stirrer and a thermometer, and the mixture is added over 2 minutes while stirring at 40 ° C., and further at 40 ° C. for 30 minutes. Stirred. Then, 0.250 parts by mass of a 25% by mass ethylenediamine aqueous solution was added, and the mixture was stirred at 40 ° C. for 1 hour, and then the infrared spectrum of the reaction solution was measured to confirm that the absorption of isocyanate groups had disappeared. Further, by removing the ethylmethylketone solvent under reduced pressure conditions and adjusting the concentration with water, an aqueous dispersion (CS-5WD) of a core-shell type aqueous polyurethane resin CS-5 having a solid content concentration of 30% by mass was prepared. Obtained. This polyurethane resin CS-5 is a polyurethane having a core of a blocked isocyanate compound BI-1 and a shell made of a nonionic prepolymer P-4.

[Manufacturing of core-shell type water-based polyurethane resin CS-6]
In a flask equipped with a stirrer, a thermometer, and a reflux cooling tube, 52.40 parts by mass of prepolymer P-1 having an anionic carboxyl group and 42 parts by mass of a methyl ethyl ketone solution of a blocked isocyanate compound BI-5 having a nonionic group were placed. The mixture was charged and stirred for 5 minutes to obtain a mixture. Separately, 150 g of water and 0.02 g of defoaming agent are added to a flask equipped with a stirrer and a thermometer, and the mixture is added over 2 minutes while stirring at 40 ° C., and further at 40 ° C. for 30 minutes. Stirred. Then, 0.250 parts by mass of a 25% by mass ethylenediamine aqueous solution was added, and the mixture was stirred at 40 ° C. for 1 hour, and then the infrared spectrum of the reaction solution was measured to confirm that the absorption of isocyanate groups had disappeared. Further, by removing the ethylmethylketone solvent under reduced pressure conditions and adjusting the concentration with water, an aqueous dispersion (CS-6WD) of a core-shell type aqueous polyurethane resin CS-6 having a solid content concentration of 30% by mass was prepared. Obtained. The polyurethane resin CS-6 is a polyurethane having a nonionic blocked isocyanate compound BI-5 as a core and an anionic prepolymer P-1 as a shell.

(Composite aqueous dispersion) [BI-PU-WD]
[Manufacture of a composite aqueous dispersion A (BI-PU-WD-A) of a blocked isocyanate compound BI-1 and a polyurethane resin PU-1 (details will be described later)]
To 66.7 parts by mass of the methyl ethyl ketone solution of the blocked isocyanate compound BI-1, 101.8 parts by mass of the methyl ethyl ketone solution of the anionic polyurethane resin PU-1 having a carboxyl group was added, and 375 parts by mass of water was gradually added while stirring. .. Methyl ethyl ketone was removed from this solution under reduced pressure under the condition of 50 ° C. or lower, and the concentration was adjusted with water to adjust the concentration with water. -PU-WD-A) was obtained.

[Manufacture of a composite aqueous dispersion B (BI-PU-WD-B) of a blocked isocyanate compound BI-1 and a polyurethane resin PU-1 (details will be described later)]
118.7 parts by mass of the methyl ethyl ketone solution of the anionic polyurethane resin PU-1 having a carboxyl group was added to 50.0 parts by mass of the methyl ethyl ketone solution of the blocked isocyanate compound BI-1, and 380 parts by mass of water was gradually added while stirring. .. Methyl ethyl ketone was removed from this solution under reduced pressure under the condition of 50 ° C. or lower, and the concentration was adjusted with water to adjust the concentration with water. -PU-WD-B) was obtained.

(Polyurethane resin)
[Manufacturing of polyurethane resin PU-1]
437.2 parts by mass of polycarbonate diol with a number average molecular weight of 2000, 192.2 parts by mass of dicyclohexylmethane-4,4'-diisocyanate, 60.8 parts by mass of dimethylolpropionic acid in a flask equipped with a stirrer, a thermometer, and a reflux cooling tube. , 13.0 parts by mass of 1,6-hexanediol and 250 parts by mass of methyl ethyl ketone as a solvent were charged, stirred at 80 ° C. for 5 hours and reacted, the infrared spectrum of the reaction solution was measured, and the absorption of isocyanate groups disappeared. I confirmed that I did. As a result, a methyl ethyl ketone solution of the polyurethane resin PU-1 having a solid content of 73.7% by mass was produced. Separately, 225 parts by mass of water was gradually added to 100 parts by mass of the methyl ethyl ketone solution of the polyurethane resin PU-1 with stirring. Under reduced pressure of this solution, methyl ethyl ketone was removed under the condition of 50 ° C. or lower, and the concentration was adjusted with water to adjust the concentration with water. PU-1WD) was obtained.

(Polyester resin)
[Manufacturing of polyester resin PE-1]
95 parts by mass of dimethyl terephthalate, 95 parts by mass of dimethyl isophthalate, 35 parts by mass of ethylene glycol, 145 parts by mass of neopentyl glycol, 0.1 part by mass of zinc acetate and 0.1 part by mass of antimony trioxide were charged into a reaction vessel and 180 ° C. The transesterification reaction was carried out over 3 hours. Next, 6.0 parts by mass of 5-sodium sulfoisophthalic acid was added, and the esterification reaction was carried out at 240 ° C. for 1 hour, and then under reduced pressure at 250 ° C. (1.33 to 0.027 kPa) for 2 hours. The polycondensation reaction was carried out to obtain a polyester resin (PE-1) having a molecular weight of 19,500. 300 parts by mass of this polyester resin (PE-1) and 140 parts by mass of butyl cellosolve were stirred at 160 ° C. for 3 hours to obtain a viscous melt, and water was gradually added to the melt to give a uniform pale white color after 1 hour. A polyester resin aqueous dispersion (PE-1WD) having a solid content of 15% by mass was prepared.

[Manufacturing of polyester resin PE-2]
Add 105 parts by mass of dimethyl 2,6-naphthalenedicarboxylate, 50 parts by mass of ethylene glycol, 36 parts by mass of hexanediol, 0.1 part by mass of zinc acetate and 0.1 part by mass of antimony trioxide into the reaction vessel, and 3 at 180 ° C. The transesterification reaction was carried out over time. Next, 8.6 parts by mass of 5-sodium sulfoisophthalic acid and 8 parts by mass of sebacic acid were added, and an esterification reaction was carried out at 240 ° C. for 1 hour, and then 1.33 to 0. A polycondensation reaction was carried out at 027 kPa) for 2 hours to obtain a polyester resin (PE-2) having a molecular weight of 18,000. 300 parts by mass of this polyester resin (PE-2) and 140 parts by mass of butyl cellosolve were stirred at 160 ° C. for 3 hours to obtain a viscous melt, and water was gradually added to the melt to give a uniform pale white color after 1 hour. A polyester resin aqueous dispersion (PE-2WD) having a solid content of 15% by mass was prepared.

(Crosslinking agent)
[Manufacturing of cross-linking agent OX-1]
A flask equipped with a stirrer, a thermometer, and a reflux condenser was charged with 150.0 parts by mass of water and 250.0 parts by mass of methoxypropyl alcohol, and heated to 80 ° C. under a nitrogen atmosphere. After that, 150.0 parts by mass of methyl methacrylate, 180.0 parts by mass of 2-isopropenyl-2-oxazoline and methoxypolyethylene glycol acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK ester AM-90G) 90.0. A monomer mixture consisting of parts by mass and a polymerization initiator solution consisting of 18.0 parts by mass of 2,2'-azobis (2-amidinopropane) dihydrochloride and 170.0 parts by mass of water as a polymerization initiator are added dropwise. The solution was dropped from the funnel under a nitrogen atmosphere over 2 hours while keeping the inside of the flask at 80 ° C. After completion of the dropping, the mixture was stirred at 80 ° C. for 5 hours and then cooled to room temperature. An appropriate amount of water was added to prepare an oxazoline-based cross-linking agent aqueous dispersion (OX-1WD) having a solid content of 40% by mass.

(acrylic resin)
[Manufacturing of acrylic resin AC-1]
T-butylperoxy-2-ethylhexano as a polymerization initiator in 356 parts by mass of methyl methacrylate, 16 parts by mass of acrylic acid, 5 parts by mass of normal butyl acrylate, 10 parts by mass of 2-hydroxyethyl methacrylate, and 372 parts by mass of methyl ethyl ketone. While stirring by adding 2 parts by mass of ate, the temperature was raised to 50 ° C. and held for 120 minutes, and then the temperature was raised to 70 ° C. and held for 180 minutes. After cooling to 40 ° C., 13 parts by mass of triethylamine was added to obtain a methyl ethyl ketone solution of an acrylic resin (AC-1). 150 parts by mass of water was gradually added to 200 parts by mass of this methyl ethyl ketone solution with stirring. Methyl ethyl ketone was removed from this solution under reduced pressure under the condition of 50 ° C. or lower, and the concentration was adjusted with water to obtain an aqueous dispersion (AC-1WD) of an acrylic resin having a solid content of 40% by mass.

(particle)
[Particle PA-1]
As the particles (PA-1), colloidal silica (Snowtex ZL; manufactured by Nissan Chemical Industries, Ltd.) having an average particle size of 80 nm and a solid content concentration of 40% by mass was used as it was as the particles (PA-1) solution.

[Particle PA-2]
As the particles (PA-2), colloidal silica (Snowtex XL; manufactured by Nissan Chemical Industries, Ltd.) having an average particle size of 40 to 60 nm having a solid content concentration of 40% by mass was used as it was as the particles (PA-2) solution.

(Manufacturing of polyester resin E-1 for base material)
(Preparation of antimony trioxide solution)
Antimony trioxide (manufactured by Sigma-Aldrich Japan LLC) was placed in a flask together with ethylene glycol, stirred at 150 ° C. for 4 hours to dissolve, and then cooled to room temperature to prepare a 20 g / l ethylene glycol solution of antimony trioxide. ..

(Polymerization of polyester resin E-1 for base material)
High-purity terephthalic acid and twice the molar amount of ethylene glycol are charged in a 2-liter stainless steel autoclave with a stirrer, 0.3 mol% of triethylamine is added to the acid component, and water is added at 250 ° C. under a pressure of 0.25 MPa. An esterification reaction was carried out while distilling off the system to obtain a mixture of bis (2-hydroxyethyl) terephthalate and an oligomer having an esterification rate of about 95% (hereinafter referred to as BHET mixture). The above antimony trioxide solution was used as a polycondensation catalyst in this BHET mixture, and the amount of antimony atoms was added to 0.04 mol% with respect to the acid component in the polyester, and then 250 under normal pressure under a nitrogen atmosphere. The mixture was stirred at ° C for 10 minutes. After that, the pressure of the reaction system was gradually lowered to 13.3 Pa (0.1 Torr) while raising the temperature to 280 ° C. over 60 minutes, and the polycondensation reaction was further carried out at 280 ° C. and 13.3 Pa for 68 minutes to carry out the intrinsic polycondensation reaction. A polyester resin E-1 having an viscosity (IV) (solvent: phenol / tetrachloroethane = 60/40) of 0.61 dl / and substantially no particles was obtained.

(Manufacturing of polyester resin E-2 for base material)
(Preparation example of aluminum compound solution)
A 20 g / l aqueous solution of basic aluminum acetate (hydroxyaluminum diacetate; manufactured by Sigma Aldrich Japan G.K.) was charged with an equal amount (volume ratio) of ethylene glycol in a flask, stirred at room temperature for 6 hours, and then depressurized. Water was distilled off from the system under 133 Pa) with stirring at 70 to 90 ° C. for several hours to prepare an ethylene glycol solution of 20 g / l of an aluminum compound.

(Preparation example of phosphorus compound solution)
As a phosphorus compound, diethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate (Irganox1222 (manufactured by BASF)) was placed in a flask together with ethylene glycol and heated at a liquid temperature of 160 ° C. for 25 hours while stirring under nitrogen substitution. Then, an ethylene glycol solution of 50 g / l of a phosphorus compound was prepared.

(Preparation of a mixture of a solution of an aluminum compound and a solution of a phosphorus compound)
Each of the ethylene glycol solutions obtained in the above-mentioned preparation example of the aluminum compound and the above-mentioned preparation example of the phosphorus compound was placed in a flask and mixed at room temperature so that the aluminum atom and the phosphorus atom had a molar ratio of 1: 2 for 1 day. A catalyst solution was prepared with stirring.

(Polymerization of polyester resin E-2 for base material)
Instead of the antimony trioxide solution as a polycondensation catalyst, a mixture of the above-mentioned aluminum compound solution and phosphorus compound solution was used, and 0.014 mol% and phosphorus atoms were used as aluminum atoms and phosphorus atoms, respectively, with respect to the acid component in the polyester. It was polymerized in the same manner as the polyester resin E-1 except that it was added so as to be 0.028 mol%. However, by setting the polymerization time to 68 minutes, a polyester resin E-2 having an intrinsic viscosity (IV) of 0.61 dl / g and substantially containing no particles was obtained.

(Example 1)
(1) Preparation of coating liquid The following coating agent was mixed with a mixed solvent (80/20 parts by mass) of water and isopropanol to adjust the total amount to 100 parts by mass. The solid content mass ratio of the aqueous dispersion of the blocked isocyanate compound BI-1 (BI-1WD-A) / the aqueous dispersion of the polyurethane resin (PU-1WD) / the aqueous dispersion of the polyester resin (PE-1WD) is 25/45. / 30, The total solid resin content concentration was 4% by mass. Further, the solid content mass ratios of the particles PA-1 and the particles PA-2 were set to 0.5 and 8, respectively, with respect to the solid content 100 of the above-mentioned resin or the like. A 10% aqueous solution of a silicone-based surfactant was added to the coating liquid in an amount of 1% by mass. Table 1 shows the compounding ratios of the resins and the like in the coating liquids of Examples and Comparative Examples.

Mixed solvent (water / isopropanol) 78.95 parts by mass An aqueous dispersion of the blocked isocyanate compound BI-1 (BI-1WD-A)
4.00 parts by mass water dispersion of polyurethane resin (PU-1WD) 7. 20 parts by mass water dispersion of polyester resin (PE-1WD) 8.00 parts by mass particles PA-1 solution 0.05 parts by mass particles PA- 2 solutions 0.80 parts by mass Surface active agent aqueous solution 1.00 parts by mass Total 100.00 parts by mass

(2) Production of Laminated Polyester Film As a film raw material polymer, resin pellets of polyester resin E-1 were dried at 135 ° C. for 6 hours under a reduced pressure of 133 Pa. Then, it was supplied to an extruder, melt-extruded into a sheet at about 280 ° C., and rapidly cooled and adhered and solidified on a rotary cooling metal roll maintained at a surface temperature of 20 ° C. to obtain an unstretched PET sheet.

This unstretched PET sheet was heated to 100 ° C. with a heated roll group and an infrared heater, and then stretched 3.5 times in the longitudinal direction with a roll group having a peripheral speed difference to obtain a uniaxially stretched PET film.

Next, the coating liquid was applied to one side of the PET film so that the coating amount was 6.0 g / m ^2, and heat-treated at 90 ° C. for 3 seconds and 40 ° C. for 3 seconds to dry. Further, the surface of the coating layer of the film was brought into contact with a tension control roll (surface roughness: 0.4S) having a diameter of 200 mm and having been hard chrome plated. The running conditions at this time were a running speed of 20 m / min, a winding angle of 60 degrees, and a running tension of 400 to 500 N / m. Then, the film was stretched 4.0 times in the width direction at 110 ° C., and heated at 230 ° C. for 5 seconds with the width direction of the film fixed. Further, a relaxation treatment in the width direction of 3% was performed to obtain a 100 μm laminated polyester film. The evaluation results of this film are shown in Table 2.

(Examples 2 to 9)
A laminated polyester film was obtained in the same manner as in Example 1 except that the coating liquid of Example 1 was changed according to the types of resins and additives of each Example of Table 1 and the mixing amount ratio of each.

(Example 10)
A laminated polyester film was obtained in the same manner as in Example 1 except that E-2 was used instead of the polyester resin E-1 as the film raw material polymer.

(Comparative Examples 1 to 10)
A laminated polyester film was obtained in the same manner as in Example 1 except that the coating liquid of Example 1 was changed according to the types of resins and additives of each Comparative Example in Table 1 and the mixing amount ratios.

Table 2 summarizes the evaluation results of each example and comparative example.

As shown in Table 2, in each of Examples 1 to 10, satisfactory results were obtained in haze, blocking resistance, adhesion to UV ink, adhesion to the hard coat layer, and moisture heat resistance. On the other hand, in Comparative Examples 1 to 10, the results were not satisfactory.

INDUSTRIAL APPLICABILITY According to the present invention, it has become possible to provide a laminated polyester film having optimum easy adhesiveness in all fields such as optical applications, packaging applications, and label applications.

Claims (3)

1. It has a coating film formed from a coating liquid containing an aqueous dispersion of a hydrophobic block isocyanate compound hydrophilized by an anionic emulsifier, a water-dispersible polyurethane resin having a carboxyl group, and a water-dispersible polyester resin. Laminated polyester film with less than 5.0 pieces / m ^{2 of peeling defects.}
2. The laminated polyester film according to claim 1, wherein the anionic emulsifier that hydrophilizes the aqueous dispersion of the hydrophobic blocked isocyanate compound is an aqueous dispersible polyurethane resin having a carboxyl group.
3. The laminated polyester film according to claim 1 or 2, which has a core-shell structure having a hydrophobic blocked isocyanate compound as a core and a water-dispersible polyurethane resin having a carboxyl group as a shell.