JP6513374B2 - Polyester resin, polyester resin aqueous liquid, and polyester resin composition - Google Patents

Description

  The present invention relates to a polyester resin, a polyester resin aqueous liquid, and a polyester resin composition, and more specifically, it is excellent in the adhesion between a polyester resin substrate and a hard coat layer, and further corresponds to a high refractive index. The present invention relates to a polyester resin, a polyester resin aqueous liquid, and a polyester resin composition.

  Conventionally, polyester films are used in various fields of industry such as packaging materials, magnetic cards, printing materials and the like. As the above-mentioned polyester film, for example, thermoplastic polyester such as polyethylene terephthalate (PET) or a copolymer of these and, if necessary, a mixture of other resins is melt extruded and molded, and then biaxially stretched , Heat fixed one is used. Such a polyester film is excellent in various physical properties such as mechanical strength, heat resistance and chemical resistance, but its surface is highly crystallographically oriented, so adhesion with, for example, paint, adhesive, ink, etc. There is a problem of poor sex.

From such a thing, the adhesiveness with paints etc. is conventionally provided by applying as a primer layer the film formed by apply | coating and forming the aqueous solution (solution or dispersion) of polyester-type resin on the surface of a polyester film conventionally. Improvements are being made.
For example, a hard coat film in which a hard coat layer is laminated on a polyester film is excellent in hardness and scratch resistance, and is used for optical applications etc. Also in this hard coat film, a primer layer is formed between the polyester film and the hard coat layer. Is provided. In the film having such a configuration, there is a problem that iris-like reflection occurs due to the difference between the refractive index of the primer layer and the refractive index of the polyester film and the hard coat layer, and the visibility is impaired.

  As means for solving the above-mentioned problems, for example, there has been proposed a method of forming, as a primer layer, a film of a polyester resin whose refractive index is increased by copolymerizing a polyol component having a fluorene structure (for example, Patent Document 1) And 2)).

  However, the primer layers formed from the polyester skeletons disclosed in Patent Documents 1 and 2 do not have sufficient adhesion to the hard coat layer, and additionally, these high refractive index polyester resins have high glass transition temperatures and hard coatings. Therefore, the adhesion to the hard coat layer tends to be further insufficient.

  As a means to improve the adhesion to the hard coat layer, it contains a polyester resin produced by the esterification reaction of a reactive raw material comprising a compound having an ester-forming functional group, and the reactive raw material contains an acrylic polymer. The polyester resin composition which has been proposed is also proposed. The primer layer formed from such a polyester resin composition intervenes between the hard coat layer formed from the ultraviolet curable resin and the substrate, whereby the adhesiveness of the hard coat layer formed from the ultraviolet curable resin is obtained. Can be improved (see, for example, Patent Document 3).

  The polyester resin composition disclosed in Patent Document 3 aims to improve the adhesion between the polyester film and the hard coat layer, but such a primer layer does not have a high refractive index, so it has a high refractive index. When the copolymerization amount of the high refractive index monomer is increased to impart the adhesive property, the adhesion to the hard coat layer may be lowered as the glass transition temperature is increased. Furthermore, although the polyester resin described in Patent Document 3 performs polymerization under reduced pressure, the polyester resin foams sharply at the time of pressure reduction due to the poor compatibility between the acrylic resin and the polyester resin, and the liquid level rises sharply, resulting in polymerization. Is also difficult.

  In recent years, hard coat agents and dilution solvents used therefor have been diversified, and in the resin composition described in Patent Document 3, adhesion may not be sufficient depending on the types of hard coat agents and the dilution solvents.

JP 2012-7154 A JP, 2009-242461, A JP, 2011-219545, A

  Therefore, under such background, the present invention is excellent in the adhesiveness between the polyester resin base material and the hard coat layer formed of, for example, an active energy ray curable resin composition, and further corresponds to the increase of the refractive index. An object of the present invention is to provide a polyester resin, a polyester resin aqueous liquid, and a polyester resin composition.

  However, as a result of intensive studies conducted by the present inventors under these circumstances, polyester resins comprising a polyol component (A), a polyvalent carboxylic acid component (B) and an acrylic resin (C) having an ester-forming functional group In the resin, by containing a polyalkylene glycol (a1) having a relatively large molecular weight as the polyol component, the adhesiveness between the polyester resin substrate and the hard coat layer formed of, for example, an active energy ray curable composition is obtained. The inventors have found that an excellent polyester-based resin can be obtained and completed the present invention.

That is, the gist of the present invention is a polyester resin comprising a polyol component (A), a polyvalent carboxylic acid component (B) and an acrylic resin (C) having an ester-forming functional group, which is a polyol component (A) The present invention relates to a polyester resin containing a polyalkylene glycol (a1) having a number average molecular weight of 1,000 to 20,000 .

  Furthermore, in the present invention, a polyester resin aqueous solution obtained by dissolving or dispersing the polyester resin in an aqueous solvent, and a polyester resin composition comprising the polyester resin and the polyester resin aqueous solution Are also provided.

The polyester-based resin of the present invention has an excellent effect of adhesion between a polyester-based resin substrate and a hard coat layer formed of, for example, an active energy ray-curable resin composition, and therefore polyesters such as polyester films It is very useful as a primer layer for providing a hard-coat layer on a system resin base material. Furthermore, the polyester resin of the present invention is required to have high visibility because it achieves high refractive index while having excellent adhesion to the polyester resin base material and the hard coat layer. Is also highly expected.
The polyester resin aqueous solution and polyester resin composition of the present invention are materials for forming a film such as a primer layer having a high refractive index and excellent in adhesion to a polyester resin base material and a hard coat layer. As very useful.

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below, which show one example of the preferred embodiments.
In the present specification, (meth) acrylic means acrylic or methacrylic, and (meth) acrylic resin polymerizes a polymerization component containing one or more of acrylate monomer and methacrylate monomer. Resin obtained by

"Polyester resin"
The polyester resin of the present invention is a polyester resin obtained by copolymerizing a polyol component (A), a polyvalent carboxylic acid component (B) and an acrylic resin (C) having an ester-forming functional group.
First, the polyol component (A) will be described.

[Polyol component (A)]
The polyol component (A) used in the present invention contains at least a polyalkylene glycol (a1) having a number average molecular weight of 1,000 to 20,000 .

When the polyalkylene glycol (a1) has a number average molecular weight of 1,000 to 20,000 , the adhesiveness to the polyester resin base material and the hard coat layer becomes good. Although the reason why the adhesion property is good is not clear, the presence of a polyalkylene glycol having a relatively large molecular weight (i) provides appropriate flexibility and flexibility, (ii) acrylic resin (C (Iii) Polyalkylene glycol acts as a linker to form an acrylic resin (C) site, which forms a phase separation structure with the site, and the acrylic resin (C) site is partially oriented at the hard coat layer interface. It is guessed that it orients at the interface of a hard-coat layer, etc.

Range of the number average molecular weight is 1, a 000～20,000, good Mashiku is 1,200～18,000, particularly preferably from 1,500 to 15,000, more preferably 1,800 12,000. If the number average molecular weight is too low, adhesion tends to be insufficient. In addition, when the number average molecular weight is too large, the compatibility with the polyester-based resin is lowered, and copolymerization tends to be difficult or uniform polymer tends to be difficult to be obtained.

In addition, a number average molecular weight is computed by a following formula from the hydroxyl value (mgKOH / g) calculated | required by the acetic anhydride pyridine method based on JISK0070.
[formula]
2 × 1000 × 56.1 ÷ hydroxyl value (mg KOH / g)

Examples of such polyalkylene glycol (a1) include polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like. Among these, polyethylene glycol is preferable in that it imparts hydrophilicity to a polyester-based resin and makes it easy to form an aqueous dispersion.
In the present invention, one or more polyalkylene glycols can be used. For example, polyalkylene glycols having different alkylene groups and polyalkylene glycols having different number average molecular weights can be used in combination.

  The content of the polyalkylene glycol (a1) in the polyol component (A) is preferably 0.01 to 10 mol%, particularly preferably 0.05 to 9 mol%, based on the whole of the polyol component (A). The amount is more preferably 0.1 to 8% by mole, and particularly preferably 0.15 to 5% by mole. If the content is too small, the adhesion tends to decrease, and if the content is too large, the refractive index, the blocking resistance, the water resistance and the adhesion tend to decrease.

  Further, in the present invention, a fluorene-based compound (a2) represented by the following general formula (1) is contained as the polyol component (A) from the viewpoint of being able to form a film having a high refractive index and a good appearance. Is preferred.

In formula (1), R ₁ is an alkylene group having 1 to 5 carbon atoms, e.g., methylene, ethylene, propylene, butylene, and pentylene group. R ₂ , R ₃ , R ₄ and R _{5 each} represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an aryl group or an aralkyl group, and these may be the same as or different from each other.
As a C1-C5 alkyl group, a methyl group, an ethyl group, a propyl group, isopropyl group, a butyl group, an isobutyl group, a pentyl group, a neopentyl group, an isopentyl group etc. are mentioned, for example. As an aryl group, a C6-C10 aryl group is mentioned, For example, a phenyl group, a tolyl group, o-xylyl group etc. are mentioned. As an aralkyl group, a C7-C20 aralkyl group is mentioned, For example, a benzyl group, a phenethyl group, etc. are mentioned.

In the fluorene compound (a2) represented by the above general formula (1), preferably R ₁ is a methylene group or an ethylene group. Further, as R ₂ , R ₃ , R ₄ and R ₅ , a hydrogen atom, a methyl group and an ethyl group are preferably mentioned, and a hydrogen atom is particularly preferable. And, as a fluorene compound (a2), bisphenoxyethanol fluorene and bis (4- (2-hydroxyethoxy) phenyl) fluorene are preferably used from the viewpoint of availability and the like. The fluorene compound (a2) can be used alone or in combination of two or more.

  The content of the fluorene compound (a2) in the polyol component (A) is preferably 5 to 99.99 mol%, particularly 20 to 95 mol%, further preferably 5 to 99.99 mol% with respect to the entire polyol component (A). It is preferably 30 to 90 mol%, particularly 45 to 85 mol%. If the content is too small, sufficient refractive index, blocking resistance and water resistance tend to be difficult to obtain, and if too large, it is difficult not only to make the water dispersion difficult but also to lower the adhesiveness. The resin aqueous liquid is applied to a polyester-based resin substrate such as a polyester film or the like, and there is a tendency for a crack to occur and a haze to occur upon drying or when the polyester film with a resin film is stretched.

  In the present invention, as the polyol component (A), in addition to the above polyalkylene glycol (a1) and the fluorene compound (a2), another dihydric alcohol may be further contained.

As said other dihydric alcohol, for example,
Ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 2,2-dimethyl-1,3- Propanediol (neopentyl glycol), 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 1,3-butadiol, 1,4-butanediol And aliphatic diols such as 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,6-hexanediol;
1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, spiroglycol, tricyclodecanedimethanol, adamantanediol, 2,2,4,4-tetramethyl-1,3 -Alicyclic diols such as cyclobutanediol;
4,4'-thiodiphenol, 4,4'-methylenediphenol, bisphenol S, bisphenol A, 4,4'-dihydroxybiphenyl, o-, m- and p-dihydroxybenzene, 2, 5-naphthalenediol, Aromatic diols such as p-xylene diol and ethylene oxide, propylene oxide adducts thereof and the like can be mentioned.
One type selected from these other dihydric alcohols may be used, or two or more types may be used in combination.

  Among these, ethylene glycol which is a linear aliphatic diol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, etc. However, it is preferably used in that it does not cause an unnecessary increase in glass transition temperature. In particular, diethylene glycol and triethylene glycol are preferable in that they impart appropriate flexibility and hydrophilicity, suppress a decrease in refractive index, and have a high boiling point and are less likely to cause distillation during the esterification reaction.

  The content of the above-mentioned other dihydric alcohol in the polyol component (A) is preferably 0.1 to 95% by mole, particularly 5 to 80% by mole, further preferably, based on the whole of the polyol component (A). It is preferably 10 to 70% by mole, particularly 15 to 55% by mole. If the content is too small, polymerization becomes difficult, flexibility is lost, adhesiveness, water dispersibility decreases, and application of an aqueous resin solution to a polyester resin substrate such as a polyester film, Cracks tend to occur and haze occurs when drying or stretching of the polyester film with a resin film, and when too large, the refractive index, the blocking resistance, and the water resistance tend to decrease.

  Further, the polyol component (A) used in the present invention may be, in addition to the above-mentioned polyols, trivalent or higher polyhydric alcohols, such as pentaerythritol, dipentaerythritol, tripentaerythritol, glycerin, trimethylolpropane and trimethylol. A small amount of ethane, 1,3,6-hexanetriol, adamantantriol or the like can be used.

[Polyvalent carboxylic acid component (B)]
The polyvalent carboxylic acid component (B) used in the present invention contains a polyvalent carboxylic acid having two or more valencies, and usually contains at least a divalent carboxylic acid. These polyvalent carboxylic acids may be in the form of ester, chloride, acid anhydride or the like.

As said bivalent carboxylic acid, for example,
Aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, benzyl malonic acid, diphenic acid, 4,4'-oxydibenzoic acid;
Malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, adipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethyl glutaric acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, itaconic acid, thiodipropionic acid , Aliphatic dicarboxylic acids such as diglycolic acid;
Alicyclic groups such as 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2,5-norbornanedicarboxylic acid, adamantanedicarboxylic acid and the like Dicarboxylic acid;
Etc.

  Furthermore, naphthalene dicarboxylic acid may be further contained, and examples of naphthalene dicarboxylic acid include 2,6-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, and 2,3-naphthalene dicarboxylic acid. One type selected from these naphthalene dicarboxylic acids may be used, or two or more types may be used in combination. From the viewpoint of availability, 2,6-naphthalenedicarboxylic acid and dimethyl 2,6-naphthalenedicarboxylate are preferable.

  In addition, for the purpose of improving the water dispersibility, a small amount of a polyvalent carboxylic acid having a sulfonate group may be contained. For example, 5-sulfoisophthalic acid, 2-sulfoisophthalic acid, 4-sulfoisophthalic acid, sulfo Examples include terephthalic acid, 4-sulfonaphthalene-2,6-dicarboxylic acid and alkali metal salts thereof. One type selected from these polyvalent carboxylic acids having a sulfonate group may be used, or two or more types may be used in combination. From the viewpoint of availability, 5-sulfoisophthalic acid, dimethyl 5-sulfoisophthalic acid and alkali metal salts thereof are preferred.

  One type selected from these polyvalent carboxylic acids may be used, or two or more types may be used in combination.

  Among these, aromatic dicarboxylic acids are preferable in terms of adhesiveness, hydrolysis resistance, and refractive index, and terephthalic acid, isophthalic acid, and esters thereof are particularly preferable in terms of adhesiveness.

  The content of divalent carboxylic acid in the polyvalent carboxylic acid component (B) is preferably 50 to 95 mol%, particularly preferably 60 to 90 mol%, with respect to the whole polyvalent carboxylic acid component (B). Furthermore, it is preferable that it is 65-88 mol%, especially 70-85 mol%. If the content is too small, the water resistance tends to decrease or gelation occurs during the production process, and if too large, the water dispersion tends to be difficult.

  As the polyvalent carboxylic acid component (B) used in the present invention, in addition to the above-mentioned various divalent carboxylic acids, a small amount of trivalent or higher polyvalent carboxylic acid is used in order to increase the branching point in the polyester resin. Can. For example, trimellitic acid, pyromellitic acid, adamantane tricarboxylic acid, trimesic acid and the like can also be used.

In the present invention, a carboxylic acid anhydride (b1) having two or more carboxylic acid anhydride structures as the polyvalent carboxylic acid component (B) in that it has a function as a chain extender and a function as a hydrophilicity imparting agent Is preferred.
The carboxylic acid anhydride (b1) may be any one having at least two carboxylic acid anhydride structures, and examples thereof include anhydrides such as carboxylic acid dianhydride, etc. And tetracarboxylic acid dianhydride is preferable from the point of water dispersibility at the time of aqueous conversion.

  Specific examples of these carboxylic acid anhydrides (b1) include, for example, 1,2,4,5-benzenetetracarboxylic acid dianhydride (pyromellitic anhydride), 1,2,3,4-butanetetracarboxylic acid Dianhydride, 1,2,3,4-pentanetetracarboxylic acid dianhydride, 3,3 ', 4,4'-benzophenonetetracarboxylic acid dianhydride, 4,4-oxydiphthalic acid dianhydride, 5- (2,5 dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 5- (2,5-dioxotetrahydrofuryl) -3-cyclohexene-1,2-dicarboxylic acid Anhydride, cyclopentane tetracarboxylic acid dianhydride, 2,3,6,7-naphthalene tetracarboxylic acid dianhydride, 1,2,5,6-naphthalene tetracarboxylic acid dianhydride, ethylene Recall bis trimellitate dianhydride, 2,2 ', 3,3'-diphenyl tetracarboxylic acid dianhydride, 2,2', 3,3'-diphenyl sulfone tetracarboxylic acid anhydride, thiophene-2,3,3 And 4,5-tetracarboxylic acid dianhydride, ethylene tetracarboxylic acid dianhydride, etc. Among them, 5- (2,5-dioxotetrahydrofuryl)-from the viewpoint that the reactivity is mild and gelation is difficult to occur. Preferably, 3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride, 5- (2,5-dioxotetrahydrofuryl) -3-cyclohexene-1,2-dicarboxylic acid anhydride, etc. are used. One selected from these can be used alone, or two or more can be used in combination.

The content of the carboxylic acid anhydride (b1) in the polyvalent carboxylic acid component (B) is preferably 5 to 50 mol%, particularly 10 to 40 mol%, based on the whole polyvalent carboxylic acid component (B). It is preferable that it is mol%, further 12 to 35 mol%, especially 15 to 30 mol%. If the content is too low, it tends to be difficult to disperse in water, and if it is too high, it tends to gel.
1 type (s) or 2 or more types can be used for a polyhydric carboxylic acid component (B).

[Acrylic resin (C) having an ester-forming functional group]
Acrylic resin (C) used by this invention is acrylic resin which has a functional group which can form an ester bond, and what has a functional group in the side chain of acrylic resin from an adhesive point is preferable. The content of the functional group in the acrylic resin (C) is preferably such that the value represented by the following formula is 2 or more, particularly 2 to 60, further 2.1 to 25 and especially 2. It is preferable that it is 2-20. In addition, when there is too much functional group content, there exists a tendency to gelatinize.

[formula]
Functional group mole number per 1 g of acrylic resin x weight average molecular weight

  Moreover, as such a functional group, a hydroxyl group, a carboxyl group, a glycidyl group, an alkoxysilyl group etc. may be mentioned, among them, in terms of adhesiveness, a hydroxyl group, a carboxyl group or a glycidyl group is preferable, and in particular, a gelation is hardly caused. Carboxyl groups are preferred.

  In the present invention, the content of the acrylic resin (C) is preferably 3 to 30% by weight, more preferably 4 to 25% by weight, particularly 5 to 20% by weight, based on the whole polyester resin of the present invention. % Is preferred. When the content is too small, the adhesion tends to be lowered, and when the content is too large, it tends to be gelled or the refractive index is lowered.

In the present invention, the composition of the acrylic resin (C) is not particularly limited, but, for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate And the like, wherein a (meth) acrylic monomer having an alkyl chain having 1 to 8 carbon atoms such as C 1 to 8 as a main component of the polymerization component, and further comprising the above-described monomer having an ester-forming functional group as the polymerization component It is preferable that the (meth) acrylic monomer having an alkyl chain having 1 to 6 carbon atoms is a main component of the polymerization component, and further, the above-described monomer having an ester-forming functional group be a polymerization component. In addition, when carbon number of the alkyl chain in a (meth) acrylic monomer is too large, there exists a tendency for water dispersibility and solvent resistance to fall.
From the viewpoint of adhesion, it is preferable that the amount of styrene be small as a copolymerization component, and the amount of copolymerization of styrene is preferably 50 mol% or less, particularly 20 mol% or less, based on the entire acrylic resin (C). Furthermore, it is preferably 5 mol% or less, particularly 0 mol%.

In the present invention, the weight average molecular weight of the acrylic resin (C) is preferably 500 to 30,000, particularly preferably 1,000 to 20,000, and further preferably 1,500 to 15,000. When the weight average molecular weight is too small, the terminal double bond concentration of the acrylic resin (C) is high and gelation tends to occur, and adhesion tends to decrease, and when the weight average molecular weight is too large, water dispersion is difficult Or the compatibility with the polyester-based resin is lowered, which tends to make copolymerization difficult and to make it difficult to obtain a uniform resin.
In addition, a weight average molecular weight can perform GPC analysis and can obtain | require by polystyrene conversion.

The glass transition temperature of the acrylic resin (C) is preferably −85 ° C. to 100 ° C., particularly preferably −70 ° C. to 80 ° C., and more preferably −60 ° C. to 70 ° C. If the glass transition temperature is too low, the water dispersibility and solvent resistance tend to be lowered, and if too large, the adhesion is lowered, or the resin aqueous liquid is applied to a polyester resin substrate such as a polyester film, Cracks tend to occur and haze may occur during drying or stretching of the resin coated polyester film.
The glass transition temperature can be determined by a differential scanning calorimeter.

[Method of producing polyester resin]
The polyester-based resin of the present invention comprises the above-mentioned polyol component (A), polyvalent carboxylic acid component (B) and acrylic resin (C) having an ester-forming functional group, and a method for producing such an ester-based resin For example,
[I] A carboxylic acid having at least two carboxylic acid anhydride structures, a hydroxyl group-containing prepolymer comprising a polyol component (A), a polyvalent carboxylic acid component (B) and an acrylic resin (C) having an ester-forming functional group A method of chain extension with an acid anhydride (b1),
[II] After forming a polyester polyol consisting of a polyol component (A) and a polyvalent carboxylic acid component (B) with a carboxylic acid anhydride (b1) having two or more carboxylic acid anhydride structures, it is possible to form an ester There is a method of reacting an acrylic resin (C) having a functional group.

The method of [I] will be described.
First, a predetermined amount of the polyol component (A), the polyvalent carboxylic acid component (B) excluding the carboxylic acid anhydride (b1), and the acrylic resin (C) having an ester-forming functional group are mixed without using any solvent. At this time, the ratio (molar ratio) of the polyol component (A) to the polyvalent carboxylic acid component (B) excluding the carboxylic acid anhydride (b1) is the polyol component per 1 mol of the polyvalent carboxylic acid component (B) It is preferable to make (A) 1.1 to 2 moles. However, it is not limited to this range, and can be appropriately adjusted by the reaction.

  This mixture is charged in an appropriate reactor, and the mixture is heated to usually 170 to 250 ° C. to promote the esterification reaction or transesterification reaction while distilling off the by-product water or methanol, thereby producing a hydroxyl group-containing prepolymer. Produce a polymer. In addition, you may mix | blend acrylic resin (C) after the chain extension by the below-mentioned carboxylic acid anhydride (b1).

  Further, a hydroxyl group-containing prepolymer comprising an acrylic resin (C) having a polyvalent carboxylic acid component (B) excluding an polyol component (A), a carboxylic acid anhydride (b1) and an ester-forming functional group is The polyester resin can be obtained by chain extension with a carboxylic acid anhydride (b1) having two or more compound structures.

  A carboxylic acid having at least two carboxylic acid anhydride structures, a hydroxyl group-containing prepolymer obtained from the above-mentioned polyol component (A), polyvalent carboxylic acid component (B) and acrylic resin (C) having an ester-forming functional group When chain-extending with an acid anhydride (b1), the reaction can proceed even at room temperature, but can usually be started at 230 ° C. or less, preferably 150 to 210 ° C., particularly preferably 165 to 200 ° C. Therefore, a solvent is not necessarily required in the above reaction, but if the viscosity of the reactant at such temperature is too high, a suitable solvent may be used to facilitate stirring.

  Examples of such solvents include ester solvents such as methyl acetate, ethyl acetate, butyl acetate, methyl acetoacetate, ethyl acetoacetate, ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, benzene, toluene, xylene, mesitylene, Aromatic solvents such as pseudocumene, alcohol solvents such as methanol, ethanol and isopropyl alcohol, amide solvents such as dimethylformamide and dimethylacetamide, glycol ether solvents such as butyl cellosolve and butyl carbitol, and acetate solvents thereof It can be mentioned.

  The reaction is preferably allowed to proceed generally at a temperature of 150 to 210 ° C. for 0.2 to 4 hours. Particularly preferably, the reaction is allowed to proceed at a temperature of 165 to 200 ° C. for 0.5 to 3 hours.

The method of [II] will be described.
The polyester polyol comprising the polyol component (A) and the polyvalent carboxylic acid component (B) can be obtained by a known method.
Furthermore, a carboxylic acid anhydride (b1) having two or more carboxylic acid anhydride structures is added to the obtained polyester polyol, chain extension is performed under the same conditions as described above, and then an acrylic resin (C) is blended, The reaction can be allowed to proceed at 165 to 200 ° C. for 0.2 to 3 hours.

In the above methods [I] and [II], an esterification catalyst, a transesterification catalyst, other polymerization catalysts and the like can be appropriately blended in the reaction, and for example, tetrabutoxy titanium can be used. In addition, various additives such as other stabilizers may be used.
Thus, a massive polyester resin is obtained by the above-mentioned method.

The weight average molecular weight of the polyester resin of the present invention thus obtained is preferably 2,000 to 60,000, particularly preferably 3,500 to 50,000, and more preferably 5,000 to 40,000. is there. If the weight average molecular weight of the polyester resin is too large, the preparation of the aqueous liquid, particularly the aqueous dispersion tends to be difficult, and the compatibility with other components tends to be reduced. In addition, when the weight average molecular weight is too small, when a film such as a primer layer is formed on a polyester resin substrate such as a polyester film using an aqueous liquid of such a resin, the toughness and the heat and humidity resistance of the film tend to decrease. There is.
In the present invention, the weight average molecular weight can be determined, for example, by polystyrene analysis by GPC analysis.

The glass transition temperature (Tg) of the polyester resin of the present invention is preferably 40 to 140 ° C., particularly preferably 50 to 120 ° C., and still more preferably 60 to 105 ° C. If the glass transition temperature is too high, the adhesiveness may be reduced, or a resin aqueous liquid may be applied to a polyester resin substrate such as a polyester film, or cracks may occur during drying or stretching of the resin film-coated polyester film. Tends to occur. When the glass transition temperature is too low, the heat resistance, the blocking resistance and the refractive index tend to be lowered.
The glass transition temperature (Tg) of the polyester-based resin can be measured, for example, using a differential scanning calorimeter.

The acid value of the polyester resin of the present invention is preferably 15 to 150 mg KOH / g, particularly preferably 20 to 100 mg KOH / g, and further preferably 30 to 80 mg KOH / g. When the acid value is too high, the water resistance and the temporal stability of the aqueous dispersion tend to be lowered, and when too low, the water dispersion tends to be difficult.
The acid value of the polyester resin can be determined, for example, by neutralization titration based on JIS K0070.

The refractive index of the polyester resin of the present invention is preferably 1.56 or more, particularly preferably 1.56 to 1.64, more preferably 1.57 to 1.63, and particularly preferably 1.58 to 1.62. When the refractive index is too high, the glass transition temperature becomes too high, and the resin aqueous liquid is coated on a polyester resin substrate such as polyester film, cracks are generated during drying or when the polyester film with a resin film is stretched If the hardness is too low, iris-like reflection occurs during lamination of the hard coat layer, which tends to impair visibility.
In addition, the refractive index said here is a refractive index with respect to D line | wire (589 nm) in 25 degreeC.
The refractive index of the polyester resin can be measured, for example, using an Abbe refractometer.

<< Polyester resin aqueous solution >>
The polyester resin aqueous solution of the present invention is obtained by dissolving or dispersing the polyester resin obtained as described above in an aqueous solvent, and usually, the polyester resin is neutralized with a neutralizing agent to obtain an aqueous solution. It can be obtained by dissolving or dispersing in a solvent.

  The neutralizing agent is not particularly limited as long as it can neutralize the carboxyl group of the polyester resin. For example, metal hydroxides such as lithium hydroxide, potassium hydroxide and sodium hydroxide; ethylamine, Diethylamine, triethylamine, propylamine, isopropylamine, iminobispropylamine, 3-ethoxypropylamine, 3-diethylaminopropylamine, diethanolamine, triethanolamine, N, N-diethylethanolamine, N, N-dimethylethanolamine, amino Organic amines such as ethanolamine, morpholine, N-methylmorpholine, N-ethylmorpholine; and ammonia. One type selected from these neutralizing agents may be used, or two or more types may be used in combination.

  Among these neutralizing agents, those having a boiling point of 150 ° C. or less are preferable in that they are easily volatilized when obtaining a film by drying and the water resistance of the obtained film. In particular, ammonia, diethylamine and triethylamine are preferable from the viewpoints of high versatility, low boiling point and easy volatilization at the time of drying, and triethylamine and ammonia are particularly preferable in that they are particularly excellent in the dispersion stability of the polyester resin.

  Examples of the aqueous solvent include water or a mixture of water and an appropriate hydrophilic organic solvent. Examples of the hydrophilic organic solvent include ketones such as acetone; alcohols such as methanol, ethanol and isopropyl alcohol; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monobutyl ether and ethylene glycol monotertiary butyl ether; One that can be mixed with water is mentioned. In particular, ethylene glycol monobutyl ether (butyl cellosolve), ethylene glycol monotertiary butyl ether, and isopropyl alcohol are preferably used. When using a hydrophilic organic solvent, the ratio with respect to the whole of polyester resin aqueous solution is suitably set. For example, although it can set as the range of 0 to 20 weight%, the ratio of the hydrophilic organic solvent with respect to the whole aqueous liquid is not limited to the said range. One type selected from these aqueous solvents may be used, or two or more types may be used in combination.

  Moreover, surfactant, such as an anionic surfactant and a nonionic surfactant, can be mix | blended with this polyester-based resin aqueous liquid as needed. By blending the surfactant, it is possible to improve the wettability to the polyester-based resin substrate when the polyester-based resin aqueous solution is applied to a polyester-based resin substrate such as a polyester film to form a film. As the surfactant, any appropriate one may be used, such as polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, fatty acid metal soap, alkyl sulfate, alkyl sulfonate, Alkyl sulfosuccinate, dodecylbenzene sulfonate and the like can be mentioned. One type selected from these surfactants may be used, or two or more types may be used in combination.

  In addition, a crosslinking agent, an antistatic agent, a filler, an ultraviolet absorber, a lubricant, a coloring agent, and the like may be further added to the polyester resin aqueous solution, as necessary.

  The concentration of the solid content of the aqueous solution of polyester resin is appropriately adjusted so that a good film can be formed by coating film formation while securing good dispersibility of the polyester resin, for example, 5 to 30 weight. % Is preferred, and 5 to 20% by weight is particularly preferred.

Next, the polyester film with a film in which the film which functions as a primer layer was formed in the surface of a polyester film using polyester resin aqueous liquid of this invention is demonstrated.
The polyester resin aqueous solution is applied to a polyester film and dried by heating to form a film, whereby a polyester film with a film can be obtained. The coated polyester film may be further stretched.

  As the polyester film, any of conventionally known ones can be used. For example, polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, a copolymer obtained by copolymerizing these with another copolymer component, etc. Films can be mentioned. Although this polyester film may be either unstretched or stretched, it is preferable to use a stretched film, and in particular, it is desirable to use a biaxially stretched film.

As this polyester film, those produced by a conventionally known appropriate method can be used. For example, an unstretched polyester film can be obtained by melting polyester as a raw material, extruding it into a sheet, and cooling with a cooling drum.
In addition, after the unstretched polyester film is stretched uniaxially or biaxially, it is thermally fixed, and if necessary, subjected to a heat relaxation treatment, to obtain a uniaxially stretched film or a biaxially stretched film.

  An appropriate method can be adopted for coating film formation of the polyester resin aqueous solution on the polyester film. At this time, for example, a polyester resin aqueous solution is applied to one side or both sides of an unstretched film or a uniaxially stretched film by an appropriate method such as kiss coat, reverse coat, gravure coat, die coat, etc. The film can then be stretched to form a biaxially stretched film. Alternatively, an aqueous polyester-based resin solution may be applied to the secondary stretched film by an appropriate method, and the film may be formed by heating and drying. At this time, the coating amount of the polyester resin aqueous solution is appropriately set. For example, the thickness of the dry coating film is preferably 0.01 to 5 μm, particularly 0.01 to 2 μm, further 0.01 to 1 μm, particularly Preferably, the thickness is in the range of 0.05 to 0.15 μm.

  The coated polyester film thus obtained is excellent in the adhesion between the polyester resin base material and the hard coat layer formed of, for example, an active energy ray curable resin composition, and is a primer layer having a high refractive index, etc. It is very useful as a material for forming a coating of Therefore, the coated polyester film has good visibility even when used for optical applications.

<< Polyester-based resin composition >>
The polyester-based resin composition of the present invention comprises the polyester-based resin obtained as described above or the polyester-based resin aqueous solution, and various forms such as liquid, granular, powdery, etc. It can be taken.
In the polyester resin composition of the present invention, if necessary, a crosslinking agent, an antioxidant such as a hindered phenol, a heat stabilizer, a glass fiber, an inorganic / organic filler, a colorant, a flame retardant, a softener Dispersants, wetting agents, emulsifiers, gelling agents, antifoaming agents, other thermoplastic resins and the like can be contained to the extent that the effects of the present invention are not impaired.
The polyester resin composition of the present invention can be used as a film, a sheet, a molded article such as a cup, an adhesive, a paint, a coating agent and the like.

  EXAMPLES Hereinafter, the present invention will be more specifically described by way of examples. However, the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In the examples, "%" and "parts" mean weight basis.

Example 1
<Production of polyester resin>
541 parts (0.279 moles) of dimethyl terephthalate, 541 parts (0.279 moles) of dimethyl isophthalate, 2442 parts (0.557 moles) of bis (4- (2-hydroxyethoxy) phenyl) fluorene, 201 parts of diethylene glycol 0.189 moles), 334 parts (0.017 moles) of polyethylene glycol having a number average molecular weight of 2,000, and an acrylic resin “UC-3000” having a carboxyl group (Toagosei Co., Ltd., acid value: 86 mg KOH / g, weight 460 parts of average molecular weight 10,000, glass transition temperature 66 ° C., 0.7 parts of tetrabutoxytitanium as catalyst, 0.5 parts of zinc acetate dihydrate, ester of tertiary butyl catechol 4.6 parts as polymerization inhibitor Charge into an exchange reactor and heat up from 180 ° C to 250 ° C in 2 hours under nitrogen atmosphere , Distill the methanol to carry out an ester exchange reaction at 250 ° C. until the end.
Then, after cooling to 180 ° C., 441 parts (0.167 mol) of 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride as a carboxylic acid anhydride ) Was added, and reaction was carried out at 180 ° C. for 1.5 hours to advance chain extension to obtain a polyester resin. The composition of this polyester resin is shown in Table 1.
In Table 1, the numerical values of the respective compounds in the columns of the polyol component (A) and the polyvalent carboxylic acid component (B) represent the mole fraction of the compound with respect to the component (A) or the component (B). The numerical value of the compound in the column of the functional group-containing acrylic resin (C) indicates the content (% by weight) of the acrylic resin (C) with respect to the entire polyester resin.

[Examples 2, 4 to 8 and Comparative Examples 1, 2, 4]
As shown in Table 1, a polyester-based resin was manufactured by performing the same operation as in Example 1 except that the copolymerization components and the ratio thereof were changed.

[Example 3]
<Production of polyester resin>
576 parts (0.297 mol) of dimethyl terephthalate, 576 parts (0.297 mol) of dimethyl isophthalate, 2600 parts (0.593 mol) of bis (4- (2-hydroxyethoxy) phenyl) fluorene, 184 parts of diethylene glycol 0.173 mol), 95 parts (0.005 mol) of polyethylene glycol having a number average molecular weight of 2,000, 0.7 part of tetrabutoxytitanium as a catalyst, 0.5 part of zinc acetate dihydrate in a transesterification reactor After charging, the temperature was raised from 180 ° C. to 250 ° C. in 2 hours under a nitrogen atmosphere, and transesterification was performed at 250 ° C. until distillation of methanol was completed.
Then, after cooling to 180 ° C., 470 parts (0.178 moles) of 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid anhydride as a carboxylic acid anhydride ) Was added, and reaction was allowed to proceed at 180 ° C. for 1 hour to allow chain extension to proceed.
Subsequently, an acrylic resin "UG-4010" having a tertiary butyl catechol of 4.6 parts as a polymerization inhibitor and a glycidyl group (manufactured by Toagosei Co., Ltd., epoxy value 1.4 meq / g, weight average molecular weight 2,900, glass A polyester-based resin was obtained by charging 457 parts of transition temperature (-55 ° C.) and further reacting at 180 ° C. for 1 hour. The composition of this polyester resin is shown in Table 1.

Comparative Example 3
<Production of polyester resin>
1224 parts (0.630 mol) of dimethyl isophthalate, 527 parts (0.178 mol) of dimethyl sodium 5-sulfoisophthalate, 1552 parts (0.354 mol) of bis (4- (2-hydroxyethoxy) phenyl) fluorene, 1150 parts (0.363 mol) of ethylene oxide 2 mol adduct of bisphenol A, 1053 parts (1.696 mol) of ethylene glycol, 194 parts (0.001 mol) of polyethylene glycol having a number average molecular weight of 2,000, tetramer as a catalyst 0.7 parts of butoxytitanium and 0.5 parts of zinc acetate dihydrate are charged in a transesterification reactor, and heated from 180 ° C. to 240 ° C. in 2 hours under a nitrogen atmosphere, and methanol distillation ends Transesterification was performed at 240 ° C. up to.
Then, while raising the temperature to 250 ° C., the inside of the system was gradually depressurized to about 1 mmHg, and the polycondensation reaction was allowed to proceed while distilling off excess glycol, to obtain a polyester resin. The composition of this polyester resin is shown in Table 1.

  The physical properties of the polyester resin thus obtained were measured according to the following method, and the results are shown in Table 2.

[Glass transition temperature (Tg)]
It measured using the differential scanning calorimeter DSC Q20 made from TA Instruments.

[Acid number]
0.5 g of a polyester resin was dissolved in a mixed solvent of 7/3 (toluene / methanol) toluene and methanol, and determined by neutralization titration based on JIS K 0070.

[Weight average molecular weight]
GPC measurement was performed using HLC-8320 manufactured by Tosoh Corporation, and the value was determined from polystyrene conversion.

[Refractive index]
The refractive index with respect to D line | wire (589 nm) in 25 degreeC was measured using Atago Co., Ltd. Abbe refracting system DR-M4.

The abbreviations shown in Table 1 represent the following compounds.
BPEF: bis (4- (2-hydroxyethoxy) phenyl) fluorene EG: ethylene glycol DEG: diethylene glycol BisA-EO: ethylene oxide 2 molar adduct of bisphenol A PEG-0.6 K: polyethylene glycol of number average molecular weight 600 PEG- 2K: polyethylene glycol having a number average molecular weight of 2,000 PEG-3.4 K: polyethylene glycol having a number average molecular weight of 3,400 PEG-8.3 K: polyethylene glycol having a number average molecular weight of 8,300 PTMG-2K: number average molecular weight 2, 000 polytetramethylene glycol

DMT: dimethyl terephthalate DMI: dimethyl isophthalate SIPM: dimethyl sodium 5-sulfoisophthalate SuAn: succinic anhydride B-4400: 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1 , 2-dicarboxylic acid anhydride

UC-3000: Acrylic resin having a carboxyl group "UC-3000" (manufactured by Toagosei Co., Ltd., acid value 86 mg KOH / g, weight average molecular weight 10,000, glass transition temperature 66 ° C., functional group content 15.3)
UC-3510: Acrylic resin having a carboxyl group "UC-3510" (manufactured by Toagosei Co., Ltd., acid value 80 mg KOH / g, weight average molecular weight 2,000, glass transition temperature -56 ° C, functional group content 2.9 )
1-A: Acrylic resin having a hydroxyl group "Actflow 1-A" (manufactured by Soken Chemical Co., Ltd., hydroxyl value 30 mg KOH / g, weight average molecular weight 10,000, glass transition temperature -67 ° C, functional group content 5. 3)
UG-4010: Acrylic resin having a glycidyl group "UG-4010" (manufactured by Toagosei Co., Ltd., epoxy value 1.4 meq / g, weight average molecular weight 2,900, glass transition temperature -55 ° C, functional group content 4 .1)
In addition, functional group content was computed according to the following formula.
[formula]
Functional group mole number per 1 g of acrylic resin x weight average molecular weight

<Preparation of Polyester Resin Aqueous Liquid>
With respect to the polyester resins obtained in Examples 1 to 8 and Comparative Examples 1, 2 and 4, 70 parts of polyester resin, 823 parts of water, 100 parts of isopropyl alcohol and 7 parts of 25% ammonia water are charged in a reactor, The temperature was raised to 0 ° C., and the solution was dissolved while stirring to prepare a polyester resin aqueous solution (water dispersion) having a solid content concentration of 7% (% by weight).

  With respect to the polyester resin obtained in Comparative Example 3, an aqueous dispersion was prepared in the same manner as described above except that 25% ammonia water was not used.

  Using the polyester resin aqueous solution thus obtained, the adhesion to the hard coat layer was evaluated according to the following method. The results are shown in Table 2.

〔Adhesiveness〕
The aqueous dispersion of polyester resin obtained in Examples and Comparative Examples was applied to a bar coater No. 1 on a PET film (Lumirror T60 manufactured by Toray Industries, Inc., thickness 100 μm). It apply | coated in 6 and making it dry at 150 degreeC for 3 minutes formed the 1-micrometer-thick primer layer.
Next, the ultraviolet curable resin composition which consists of the mixing | blending component shown below was carried out on the said primer layer for bar coater No. 10 and was dried at 60 ° C. for 3 minutes. Subsequently, the ultraviolet curable resin composition is cured by irradiating ultraviolet light at 450 mJ / cm ² using a metal halide lamp having an irradiation intensity of 80 W / cm set at a height of 13 cm from the coated surface, and a hard 2 μm thick The coat layer was formed.
<UV-curable resin composition>
Mixture containing the following urethane acrylate compound for hard coat: 130 parts isopropyl alcohol: 837 parts methyl isobutyl ketone: 33 parts Photopolymerization initiator “Irgacure-184” (manufactured by Ciba Specialty Chemicals): 5.2 parts

(Urethane acrylate compound-containing mixture for hard coat)
15 g (0.07 mol) of isophorone diisocyanate, a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (hydroxyl value 116 mg KOH / g) in a four-necked flask equipped with a thermometer, stirrer, water-cooled condenser and nitrogen gas blowing port 85 g, 0.06 g of 2,6-di-tert-butylcresol as a polymerization inhibitor, 0.02 g of dibutyltin dilaurate as a reaction catalyst are charged, reacted at 60 ° C., and the residual isocyanate group becomes 0.3% or less The reaction was completed to obtain a mixture of 51.1 g (weight average molecular weight: 1,200) of a urethane acrylate compound, 16.3 g of pentaerythritol triacrylate, and 32.6 g of pentaerythritol tetraacrylate.

100 crosscuts of 1 mm ² are placed in the hard coat layer thus formed, Sellotape (registered trademark) made by Nichiban Co., Ltd. is pasted on it, and after rubbing on the tape with a plastic eraser, the tape is fully adhered The adhesive property was evaluated by the number of remaining hard coat layers by peeling rapidly in the 90 ° C. direction.

  From the above results, Examples 1 to 8 polyesters comprising a polyol component (A) containing a polyalkylene glycol having a predetermined number average molecular weight, an acrylic resin (C) having a polyvalent carboxylic acid component and an ester-forming functional group It turns out that the adhesiveness of a polyester-type resin base material and a hard-coat layer is favorable, although it is a high refractive index and high glass transition temperature.

  On the other hand, in Comparative Example 1 where the polyalkylene glycol is not contained and Comparative Example 2 where the molecular weight of the polyalkylene glycol is low, the adhesion between the polyester resin substrate and the hard coat layer is insufficient. In addition, in Comparative Example 3 which does not contain an acrylic resin having an ester-forming functional group, and Comparative Example 4 which does not contain an acrylic resin and a polyalkylene glycol, the adhesion between the polyester resin substrate and the hard coat layer is insufficient. there were.

  The polyester resin of the present invention can be suitably used as a primer for a polyester film on which a hard coat layer or the like is laminated. The polyester-based resin of the present invention can ensure the adhesion between the polyester-based resin base and the hard coat layer while maintaining a high refractive index, so that iris-like reflection can be suppressed, and visibility and designability Can be suitably used in applications requiring

Claims (11)

A polyester resin comprising a polyol component (A), a polyvalent carboxylic acid component (B) and an acrylic resin (C) having an ester-forming functional group,
A polyester resin comprising a polyalkylene glycol (a1) having a number average molecular weight of 1,000 to 20,000 as the polyol component (A). The polyester resin according to claim 1, characterized in that the polyalkylene glycol (a1) having a number average molecular weight of 1,000 to 20,000 is contained in an amount of 0.01 to 10 mol% based on the whole of the polyol component (A). . The polyester resin according to claim 1 or 2, wherein a fluorene compound (a2) represented by the following general formula (1) is contained as the polyol component (A).

[In formula (1), R ₁ is an alkylene group of 1 to 5 carbon atoms, R ₂ , R ₃ , R ₄ and R ₅ are a hydrogen atom, an alkyl group of 1 to 5 carbon atoms, an aryl group or an aralkyl group These may be the same as or different from one another. ]   The polyester resin according to claim 3, wherein the fluorene compound (a2) represented by the general formula (1) is contained in an amount of 5 to 99.99 mol% based on the whole of the polyol component (A).   The acrylic resin (C) having an ester-forming functional group is a carboxyl group-containing acrylic resin (c1), a hydroxyl group-containing acrylic resin (c2), a glycidyl group-containing acrylic resin (c3) or an alkoxysilyl group-containing acrylic resin The polyester resin according to any one of claims 1 to 4, which is a resin (c4).   The polyester-based resin according to any one of claims 1 to 5, wherein a carboxylic acid anhydride (b1) having two or more carboxylic acid anhydride structures is contained as the polyvalent carboxylic acid component (B).   Carboxylic anhydride having at least two carboxylic acid anhydride structures, a hydroxyl group-containing prepolymer comprising a polyol component (A), a polyvalent carboxylic acid component (B) and an acrylic resin (C) having an ester-forming functional group The polyester resin according to claim 6, which is chain-extended by (b1).   An ester-forming functional group is obtained by chain-extending a polyester polyol consisting of a polyol component (A) and a polyvalent carboxylic acid component (B) with a carboxylic acid anhydride (b1) having two or more carboxylic acid anhydride structures. 7. The polyester resin according to claim 6, wherein the polyester resin is reacted with the acrylic resin (C).   The polyester resin according to any one of claims 1 to 8, which has a refractive index of 1.56 or more.   A polyester resin aqueous solution obtained by dissolving or dispersing the polyester resin according to any one of claims 1 to 9 in an aqueous solvent.   A polyester resin composition comprising the polyester resin according to any one of claims 1 to 9 or the polyester resin aqueous solution according to claim 10.