JP2010215770A - Aqueous dispersion of copolyester resin and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous dispersion of a copolyester resin which is excellent in shelf stability and is capable of forming a resin film excellent in heat resistance, hot water resistance and adhesion to a substrate. <P>SOLUTION: The aqueous dispersion of a copolyester resin comprises the following components: (A) the copolyester resin; (B) a basic compound; (C) 0-25 mass% organic solvent; and (D) water, provided that fine particles of the copolyester resin are uniformly dispersed in an aqueous medium. The aqueous dispersion of the copolyester resin contains 5-50 mass% copolyester resin, and the copolyester resin has a volume average particle size of &le;300 nm. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a copolymer polyester resin aqueous dispersion that is excellent in storage stability, heat resistant, hot water resistant, and capable of forming a resin film that is applied to various substrates and has excellent adhesion.

  Polyester resin is used as a film-forming resin and is used in large quantities as a binder component in the fields of paints, inks, adhesives, coating agents, etc. due to its excellent film processability, weather resistance, and adhesion to various substrates. Has been.

  In recent years, the use of organic solvents has tended to be restricted from the standpoints of environmental protection, resource conservation, dangerous goods regulations by the Fire Service Act, and workplace environment improvement. Polyester resin is used as a polyester resin binder that can be used in the above applications. A polyester resin aqueous dispersion finely dispersed in an aqueous medium has been actively developed.

  In order to prepare an aqueous polyester resin dispersion having a high glass transition point (Tg), a copolymer polyester having a relatively high Tg has water-soluble functional groups such as 5-sulfoisophthalic acid and 5-hydroxyisophthalic acid. A method of copolymerizing monomers is known, but an aqueous polyester resin dispersion obtained by such a method has poor water resistance due to water-soluble functional groups.

  Patent Documents 1 to 3 disclose a method of dispersing a copolyester resin imparted with an acid value of 8 mgKOH / g or more together with alcohol and water in order to increase water resistance. However, although the polyester resin aqueous dispersion obtained by such a method has good water resistance, a decrease in molecular weight is inevitable because it imparts a high acid value, and even in the polyester resin aqueous dispersion having the highest Tg, It was at 70 ° C.

  Therefore, in Patent Document 4, the inventors disclose a technique of dispersing a low acid number copolymer polyester in order to further increase the molecular weight and Tg while maintaining water resistance. However, even with an aqueous polyester resin dispersion obtained by such a method, since the Tg of the copolyester before giving an acid value is low, it is possible to obtain an aqueous dispersion capable of producing a film sufficiently excellent in heat resistance and hot water resistance. However, the aqueous polyester resin dispersion having the highest Tg is 83 ° C., and there has been a demand for an aqueous polyester resin dispersion having a high Tg.

JP 09-296100 A JP 2000-26709 A JP 2000-313793 A JP-T-2004-37924

  The present invention provides an aqueous copolymerized polyester resin dispersion capable of forming a resin film having excellent storage stability, heat resistance, hot water resistance, and excellent adhesion to a substrate. With the goal.

  As a result of intensive research to solve such problems, the present inventors have obtained a phase inversion of a copolymer polyester resin obtained by copolymerizing isosorbide without copolymerizing a monomer having a water-soluble functional group. By emulsifying, an aqueous copolymer polyester resin dispersion having excellent storage stability can be obtained, and the resin film formed therefrom has good heat resistance and hot water resistance, and adhesion to a substrate. Was found to be good, and the present invention was reached.

  That is, the gist of the present invention is as follows.

(1) The following components (A) to (D) are blended, and a copolymer polyester resin aqueous dispersion in which fine particles of the copolymer polyester resin are uniformly dispersed in an aqueous medium, the copolymer polyester resin aqueous dispersion A copolymer polyester resin aqueous dispersion, wherein the content of the copolymer polyester resin in the body is 5 to 50% by mass, and the volume average particle size of the copolymer polyester resin is 300 nm or less.
(A) mainly composed of a dicarboxylic acid component and a glycol component, including an aromatic dicarboxylic acid as the dicarboxylic acid component, isosorbide as the glycol component, an acid value of 2 to 12 mg KOH / g, and a glass transition temperature of 85 ° C. or higher, A copolymerized polyester resin having a number average molecular weight of 4000 or more.
(B) 0-25 mass% of basic compound (C) organic solvent.
(D) Water (2) The method for producing an aqueous dispersion of a copolymerized polyester resin according to (1), wherein the copolymerized polyester resin is dissolved in an organic solvent and then mixed with water and a basic compound and dispersed. .
(3) A copolymerized polyester resin film obtained from the aqueous copolymerized polyester resin dispersion of (1).

  According to the present invention, the copolymerized polyester resin obtained by copolymerizing isosorbide without copolymerizing a monomer having a water-soluble functional group is excellent in heat resistance, so that it can be stored by phase inversion emulsification. It is possible to provide an aqueous copolymerized polyester resin dispersion capable of forming a resin film having excellent stability, excellent heat resistance and hot water resistance, and excellent adhesion to a substrate.

  Hereinafter, the present invention will be described in detail.

  The aqueous copolymerized polyester resin dispersion of the present invention (hereinafter referred to as an aqueous dispersion) is composed of (A) a copolymerized polyester resin, (B) a basic compound, (C) an organic solvent, and (D) water. The

  First, the copolymerized polyester resin (A) will be described.

  The copolymer polyester resin referred to in the present invention is a copolymer polyester resin composed of equimolar amounts of a dicarboxylic acid (AA) component and a glycol (AB) component, and an aromatic dicarboxylic acid as a dicarboxylic acid component. As a glycol component containing an acid, it is necessary to copolymerize isosorbide. You may copolymerize a hydroxycarboxylic acid (AC) component as needed.

  Examples of the aromatic carboxylic acid used as the dicarboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, 4,4'-dicarboxybiphenyl, 5-sodium sulfoisophthalic acid, and the like. The aromatic carboxylic acid is preferably copolymerized in an amount of 40 mol% or more based on the total dicarboxylic acid component. If the aromatic carboxylic acid content is less than 40 mol%, the heat resistance of the resin film is lowered, which is not preferable. The “total carboxylic acid component” means a carboxylic acid (AA) component, a hydroxycarboxylic acid (AC) component, a monocarboxylic acid component, which can be a constituent component of the copolymerized polyester resin of the present invention, It means the total of trivalent or higher carboxylic acid components.

  Isosorbide used as a glycol component is a compound represented by the following general formula (1), and its chemical name is represented as 1,4: 3,6-dianhydro-D-sorbitol (hereinafter referred to as isosorbide).

  Isosorbide is preferably copolymerized in an amount of 3 mol% to 100 mol%, more preferably 10 mol% to 80 mol%, and most preferably 20 mol% to 80 mol%, based on the total diol component. . If it is less than 3 mol%, there is almost no effect of increasing the glass transition temperature. The “all diol component” means a diol (AB) component, a hydroxycarboxylic acid (AC) component, a monoalcohol component, trivalent or higher that can be a constituent component of the copolymer polyester resin of the present invention. Means the sum of alcohol components.

  Isosorbide can be easily obtained from renewable resources such as sugars and starch. For example, isosorbide can be obtained by hydrogenating D-glucose and subjecting it to a dehydration reaction. Isosorbide can be obtained from Rocket.

  The glass transition temperature (hereinafter referred to as Tg) of the copolyester resin of the present invention needs to be 85 ° C. or higher. Furthermore, in order to improve the heat resistance of the resulting resin film, 100 ° C. or higher is preferable, and 120 ° C. or higher is more preferable. If the Tg is lower than 85 ° C., the heat resistance required for the resulting resin film cannot be obtained, which is not suitable.

  Most preferably, the melting point (hereinafter referred to as Tm) of the copolyester resin of the present invention is not detected, but when there is a melting point, it is preferably 230 ° C. or higher. When there is a melting point, if it is lower than 230 ° C, Tg may be lower than 85 ° C, which is not preferable.

  When the copolymerized polyester resin of the present invention has a melting point, its melting energy (hereinafter abbreviated as ΔHm) needs to be 15 J / g or less, preferably 10 J / g or less, preferably 5 J / g or less. More preferably. When the melting energy is larger than 25 J / g, the crystallinity becomes high, so that the copolyester resin cannot be dissolved or swelled and cannot be dispersed.

  Tm, Tg, and ΔHm of the copolyester resin can be adjusted to the above range by setting a combination of monomers to be copolymerized.

  The number average molecular weight of the copolyester resin needs to be 4,000 or more, and is preferably 8,000 or more in order to ensure strength and toughness suitable for processing of the resulting resin film. More preferably, it is 1,000 or more. If the number average molecular weight is less than 4,000, the processability of the resin film is insufficient, which is not suitable.

  The number average molecular weight of the copolyester resin can be adjusted to the above range by controlling the polymerization time and the depolymerization amount.

  In the present invention, the acid value of the copolyester resin needs to be 2 to 12 mgKOH / g, and in order to ensure adhesion and hot water resistance in the case of a resin film, it should be 2 to 6 mgKOH / g. Preferably, 2 to 4 mg KOH / g is more preferable. When the acid value is larger than 12 mgKOH / g, the molecular weight becomes 4000 or less, and not only the glass transition temperature of the aqueous dispersion of the present invention is lowered, but also the adhesiveness and hot water resistance in the case of using a resin film are not suitable. . Further, if the acid value is less than 2 mgKOH / g, it tends to be difficult to make it water-based, and even if it can be made water-based, the volume average particle size becomes large and the storage stability is deteriorated, which is not suitable.

  Further, the copolymer polyester resin may contain a hydroxyl group within a range not impairing the water resistance of the resin film, preferably 30 mgKOH / g or less, and more preferably 20 mgKOH / g or less.

  The acid value and hydroxyl value of the copolymerized polyester resin can be adjusted to the above ranges by controlling the polymerization time and the amount of depolymerization.

  In addition, the dispersity of the molecular weight distribution of the copolyester resin is not particularly limited, but is preferably 8 or less, and more preferably 5 or less. Here, the degree of dispersion of the molecular weight distribution is a value obtained by dividing the weight average molecular weight by the number average molecular weight.

  The copolymer polyester resin of the present invention may use the following dicarboxylic acid (AA) component and glycol (AB) component, and if necessary, hydroxycarboxylic acid (AC). The components may be copolymerized.

  (A) Other dicarboxylic acid components constituting the component include oxalic acid, malonic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, octadecanedioic acid, and aicosanedioic acid. Unsaturated aliphatic dicarboxylic acids such as aliphatic dicarboxylic acid, fumaric acid, maleic acid, itaconic acid, mesaconic acid, citraconic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid Examples thereof include acid, 2,5-norbornene dicarboxylic acid, and alicyclic dicarboxylic acid of tetrahydrophthalic acid. These may be anhydrous.

Examples of other diol components constituting the component (AB) include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4 -Butanediol, 2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-amino-2-ethyl-1,3-propanediol, 2-amino-2-methyl -1,3-propanediol, 2-ethyl-2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol,
Neopentyl glycol, 3-methyl-1,5-pentanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 3 (4), 8 (9) -bis (hydroxymethyl) -tricyclo (5.2.1.1/2.6) decane, diethylene glycol, triethylene glycol, dipropylene glycol, tri Aliphatic glycols such as propylene glycol, bisphenol A, bisphenol S, bisphenol C, bisphenol Z, bisphenol AP, ethylene oxide adduct or propylene oxide adduct of 4,4′-biphenol, 1,2-cyclohexanedimethanol, 1, 3-cyclohexanedimethanol, 1,4-si Examples include cycloaliphatic glycols such as rhohexanedimethanol, polyethylene glycol, polypropylene glycol, etc. Among them, versatile ethylene glycol, 1,2-propanediol, 1,4-butanediol, and neopentyl glycol are preferable. .

  In the copolymerized polyester resin of the present invention, a hydroxycarboxylic acid (A-C) can be used depending on purposes such as appropriate flexibility, improved adhesion, and adjustment of the glass transition temperature. The (AC) component is preferably 20 mol% or less of the total carboxylic acid component. When the proportion of the component (AC) is higher than 20 mol%, the glass transition temperature is lowered, which is not preferable.

  As the component (AC), p-hydroxybenzoic acid, m-hydroxybenzoic acid, o-hydroxybenzoic acid, lactic acid, oxirane, β-propiolactone, β-butyrolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, glycolic acid, 2-hydroxybutyric acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxyisobutyric acid, 2-hydroxy-2-methylbutyric acid, 2-hydroxyvaleric acid, 3-hydroxyvaleric acid, 4 -Hydroxyvaleric acid, 5-hydroxyvaleric acid, 6-hydroxycaproic acid, 10-hydroxystearic acid and the like can be mentioned. Among them, ε-caprolactone having versatility is preferable.

  If the amount is small, a tri- or higher functional carboxylic acid component or an alcohol component may be added as a copolymerization component.

  Examples of the tri- or higher functional carboxylic acid component include aromatics such as trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic acid anhydride, trimesic acid, and the like. Examples thereof include carboxylic acids and aliphatic carboxylic acids such as 1,2,3,4-butanetetracarboxylic acid.

  Examples of the tri- or higher functional alcohol component include glycerol, trimethylolpropane, trimethylolethane, pentaerythritol, α-methylglucose, mannitol, and sorbitol.

  It is not always necessary to use one of these, and a plurality of types can be mixed and used for the copolyester resin depending on the properties to be imparted. At this time, the proportion of the tri- or higher functional monomer is suitably about 0.2 to 5 mol% with respect to the total carboxylic acid component or the total alcohol component. If the amount added is less than 0.2 mol%, the added effect does not appear, and if the amount exceeds 5 mol% is included, the gelation may exceed the gel point during polymerization.

  Moreover, monocarboxylic acid and monoalcohol may be copolymerized with the copolyester resin. Examples of monocarboxylic acids include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, benzoic acid, p-tert-butylbenzoic acid, cyclohexane acid, 4-hydroxyphenyl stearic acid, and the like. Examples of the alcohol include octyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, and 2-phenoxyethanol.

  The copolyester resin can be produced in a known polymerization kettle by combining the above monomers.

  The reaction for producing the copolyester resin comprises an esterification reaction step and a polycondensation reaction step. The esterification reaction step is a step of producing a low polymer having a desired composition from all monomers and / or a low polymer, and the polycondensation reaction is a polymerization of a desired composition by distilling off the glycol component from the low polymer. This is a process for obtaining a product.

  Hereinafter, each step will be described. In the esterification reaction, all monomer components and / or low polymers thereof are reacted by heating and melting under an inert atmosphere. Since isosorbide is a secondary alcohol, it is less reactive than a primary alcohol. Therefore, the esterification temperature is preferably 180 to 250 ° C, more preferably 220 to 250 ° C, and the reaction time is preferably 2.5 to 10 hours, and more preferably 4 to 6 hours. The reaction time is the time from the desired reaction temperature to the subsequent polycondensation reaction.

  In the polycondensation reaction, the glycol component is distilled off from the esterified product obtained by the esterification reaction at a temperature of 220 to 300 ° C. under reduced pressure, and the polycondensation reaction proceeds until a desired molecular weight is reached. The polycondensation reaction temperature is preferably 250 ° C. or higher, and more preferably 270 ° C. or higher. When the polycondensation reaction temperature is low, the copolymer polyester resin of the present invention has a high Tg of 85 ° C. or higher and a high melt viscosity, so that it is difficult to reach a desired molecular weight. The degree of vacuum is preferably 130 Pa or less. A low degree of vacuum is not preferable because the polycondensation time tends to be long. As the pressure reduction time until the pressure reaches 130 Pa or less from the atmospheric pressure, it is preferable to gradually reduce the pressure over 60 to 180 minutes. Depending on the composition, isosorbide may be distilled off and isosorbide may be precipitated from the distillate. In this case, it is preferable to heat the distillation line to 40 to 80 ° C.

  In the esterification reaction and polycondensation reaction, if necessary, organic titanate compounds such as tetrabutyl titanate, alkali metals such as zinc acetate and magnesium acetate, acetates of alkaline earth metals, trioxide Polymerization is performed using an organic tin compound such as antimony, hydroxybutyltin oxide, or tin octylate. In this case, the amount of catalyst used is preferably 1.0% by mass or less based on the mass of the resin to be produced.

  In the case where a desired acid value is imparted to the copolymerized polyester resin, a method in which a polybasic acid component is further added following the polycondensation reaction and depolymerization is performed in an inert atmosphere can be exemplified.

  In addition, bubbles may be generated in the resin when depolymerized and may not be pelletized due to the foam when discharged, but in such a case, after depolymerization, the inside of the system is again decompressed and defoamed. That's fine. The degree of pressure reduction during re-depressurization is preferably 67000 Pa or less, and more preferably 10,000 Pa. If the degree of vacuum is higher than 67000 Pa, it takes a long time to degas even if the pressure is reduced again, which is not preferable.

  Next, the content of the copolyester resin in the aqueous dispersion of the present invention will be described.

  The content of the copolyester resin in the aqueous dispersion is preferably 5 to 50% by mass, and more preferably 10 to 40% by mass. When the content of the copolyester resin exceeds 50% by mass, the viscosity of the aqueous dispersion becomes very high, and it may be difficult to form a resin film substantially, and the content is less than 5% by mass. So it's not practical.

  Next, the basic compound (B) will be described.

  The aqueous dispersion of the present invention needs to contain a basic compound. The basic compound neutralizes the carboxyl group of the copolyester resin, prevents aggregation between the fine particles due to electrostatic repulsion between the generated carboxyl anions, and provides stability to the aqueous dispersion.

  As the basic compound, an organic amine having a boiling point of 250 ° C. or lower, preferably 160 ° C. or lower, or ammonia is preferable because it easily evaporates during the formation of the resin film. Specific examples of organic amines preferably used include triethylamine, N, N-diethylethanolamine, N, N-dimethylethanolamine, aminoethanolamine, N-methyl-N, N-diethanolamine, isopropylamine, iminobispropylamine , Ethylamine, diethylamine, 3-ethoxypropylamine, 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, dimethylaminopropylamine, methyliminobispropylamine, 3-methoxypropylamine, monoethanolamine, Examples include diethanolamine, triethanolamine, morpholine, N-methylmorpholine, and N-ethylmorpholine. Among them, triethylamine, N, N-dimethylether It is preferable to use a Noruamin.

  Next, the organic solvent (C) will be described.

  The organic solvent is used for dissolving the copolymerized polyester resin (A) in the dissolution step described later.

  Examples of the organic solvent include known organic solvents, such as ketone organic solvents, aromatic hydrocarbon organic solvents, ether organic solvents, halogen-containing organic solvents, alcohol organic solvents, ester organic solvents, Examples include glycol organic solvents.

  Such ketone organic solvents include methyl ethyl ketone (2-butanone) (hereinafter referred to as MEK), acetone, diethyl ketone (3-pentanone), methyl propyl ketone (2-pentanone), methyl isobutyl ketone (4-methyl-2- Pentanone) (hereinafter referred to as MIBK), 2-hexanone, 5-methyl-2-hexanone, 2-heptanone, 3-heptanone, 4-heptanone, cyclopentanone, cyclohexanone and the like.

  As aromatic hydrocarbon organic solvents, toluene, xylene, benzene, etc., ether organic solvents as dioxane, tetrahydrofuran, and halogen-containing organic solvents as carbon tetrachloride, trichloromethane, dichloromethane, alcohols, etc. Examples of the organic solvent include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, tert-amyl alcohol, 1- Examples include ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, and cyclohexanol.

  Examples of ester organic solvents include ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, 3-methoxybutyl acetate, methyl propionate, ethyl propionate, and carbonic acid. Examples of glycol organic solvents include ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol ethyl ether acetate, diethylene glycol, diethylene glycol. Monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol ethyl ether acetate DOO, propylene glycol, propylene glycol monomethyl ether, propylene glycol monobutyl ether, can be exemplified propylene glycol methyl ether acetate. Furthermore, organic solvents, such as 3-methoxy-3-methylbutanol, 3-methoxybutanol, acetonitrile, dimethylformamide, dimethylacetamide, diacetone alcohol, ethyl acetoacetate, are mentioned.

  These organic solvents can be used alone or in combination of two or more, but in order to obtain the aqueous dispersion of the present invention, 3% by mass or more of the copolyester resin must be dissolved. It is necessary to select an organic solvent so that the organic solvent can be dissolved, more preferably an organic solvent capable of dissolving 5% by mass or more, still more preferably an organic solvent capable of dissolving 10% by mass or more, 30% by mass. An organic solvent that can be dissolved is most preferable.

  As such an organic solvent, cyclohexanone, tetrahydrofuran, acetone, MEK, MIBK, or dioxane alone can be suitably used. In the case of using a mixed solution, a mixed solution having an arbitrary mixing ratio is prepared, and the copolymerized polyester resin is dissolved in the mixed solution, or an organic solvent having a higher dissolving power for the copolymerized polyester resin. Then, the copolyester resin may be dissolved in advance, and a prescribed amount of another organic solvent may be added before the dispersion step described later. If there is a solvent removal step, the organic solvent is azeotroped with water to remove the solvent, so the solvent can be removed more efficiently when the boiling point of the organic solvent is lower than the boiling point of water. It is preferable to select an organic solvent having a boiling point lower than 100 ° C.

  Next, the organic solvent content of the aqueous dispersion of the present invention will be described.

  The content of the organic solvent in the aqueous dispersion is preferably 0 to 25% by mass, more preferably 0 to 5% by mass, further preferably 0 to 1% by mass, and 0 to 0.5%. Mass% is particularly preferred. If the content of the copolymerized polyester resin exceeds 25% by mass, the stability of the aqueous dispersion becomes very poor, such being undesirable.

  Next, the method for producing the aqueous dispersion of the present invention will be described in detail.

  The production of the aqueous dispersion of the present invention substantially comprises two steps, a dissolution step and a dispersion step, and a solvent removal step is added if necessary. The dissolving step is a step of dissolving the copolyester resin in an organic solvent, and the dispersing step is a step of dispersing the copolyester resin solution dissolved in the organic solvent in water together with the basic compound. The solvent removal step is a step of removing a part or all of the organic solvent used in the step of dissolving the copolyester resin out of the system from the obtained aqueous dispersion.

  Hereinafter, each step will be described.

  First, in the dissolving step, the copolyester resin is dissolved in the aforementioned organic solvent so as to have a concentration of about 10 to 70% by mass. As an apparatus for dissolving the copolyester resin, any apparatus may be used as long as it has a tank into which a liquid can be charged and can be appropriately stirred. Moreover, when the copolyester resin is difficult to dissolve, it may be heated.

  Next, the dispersion process will be described.

  In the dispersion step, the copolymerized polyester resin solution obtained in the dissolution step is mixed with water and a basic compound for dispersion. In the present invention, it is necessary to add the basic compound to the solution containing the copolymerized polyester resin, and gradually add water to the solution to perform dispersion. By using such a method, The particle size of the obtained aqueous dispersion can be made 300 nm or less, and the storage stability becomes good.

  The usage-amount of the basic compound in the manufacturing method of this invention is prescribed | regulated by the equivalent ratio with respect to the total molar amount of the carboxyl group of copolyester resin (A). When the acid value of the copolymerized polyester resin (A) is EmgKOH / g and the equivalent ratio of the basic compound (B) to the total molar amount of carboxyl groups of the copolymerized polyester resin is F, E is 2 or more and 8 or less. In this case, it is necessary to use within the range of the following formula (1), preferably the range of the following formula (2), more preferably the range of the following formula (3). When E is 8 or more and 12 or less, it is necessary to use in the range of the following formula (4), preferably the range of the following formula (5), more preferably the range of the following formula (6).

  When E is 2 or more and 8 or less

  When E is 8 or more and 12 or less

  When F is smaller than the range of (1), in the dispersion step, the effect of the electric repulsive force between the carboxyl anions generated by neutralizing the carboxyl groups of the copolymer polyester resin becomes insufficient, and the copolymer polyester resin becomes Problems such as aggregation and precipitation occur. Further, even if a copolyester resin is produced, the particle diameter is 300 nm or more, which is not preferable because storage stability is deteriorated. On the other hand, when F exceeds the range of (1), not only does the working environment become very bad due to the odor of the basic compound, but when the solvent removal step described later is included, the copolyester resin aggregates. It is not preferable because the solvent cannot be removed. In addition, when a solvent removal process is performed after a dispersion | distribution process, the content rate of the final basic compound in an aqueous dispersion can be made into less than 1 mass%.

  Similarly, if F is smaller than the range of (4), the effect of the electric repulsive force between carboxyl anions generated by neutralizing the carboxyl groups of the copolymer polyester resin in the dispersion step becomes insufficient, and the copolymerization is carried out. Problems such as aggregation and precipitation of the polyester resin occur. Further, even if a copolyester resin is produced, the particle diameter is 300 nm or more, which is not preferable because storage stability is deteriorated. On the other hand, when F exceeds the range of (4), not only does the working environment become very bad due to the odor of the basic compound, but when the solvent removal step described later is included, the copolyester resin aggregates. It is not preferable because the solvent cannot be removed. In addition, when a solvent removal process is performed after a dispersion | distribution process, the content rate of the final basic compound in an aqueous dispersion can be made into less than 1 mass%.

Moreover, it is preferable that the temperature at the time of performing a dispersion | distribution process is 40 degrees C or less, 30 degrees C
The following is more preferable, and 15 ° C. or lower is further preferable. When the temperature is 40 ° C. or higher, the particle size of the obtained aqueous dispersion is increased, and the storage stability is deteriorated.

  As an apparatus for performing the dispersion step, any apparatus may be used as long as it has a tank into which a liquid can be charged and can be appropriately stirred. Examples of such an apparatus include apparatuses widely known to those skilled in the art as a solid / liquid stirring apparatus and an emulsifier (for example, a homomixer). In addition, when using an emulsifier with large decoction, such as a homomixer, it is preferable to use it while cooling so that the internal temperature becomes 40 ° C. or lower.

  In addition, you may perform a dispersion | distribution process on conditions under normal pressure, pressure reduction, and pressurization.

  In order to reduce the content of the organic solvent, a desolvation step is provided, and the organic solvent contained in the aqueous dispersion obtained by the dispersion step is distilled under reduced pressure or normal pressure to obtain one organic solvent. Part or all may be removed from the system. In the case where the basic substance is contained in an amount equivalent to twice or more the total molar amount of carboxyl groups of the copolyester resin, and the solvent is removed at normal pressure over 2 hours, the resin in the system In such a case, the internal temperature is 70 ° C. or less, preferably the internal temperature is 60 ° C. or less, and more preferably the internal temperature is 50 ° C. or less. The solvent may be removed under reduced pressure while adjusting the pressure. As an apparatus for performing the solvent removal step, any apparatus may be used as long as it has a tank into which a liquid can be introduced and can be appropriately stirred.

  Next, the volume average particle diameter of the aqueous dispersion of the present invention will be described.

  Uniformly dispersed by the manufacturing method as described above, and in appearance, a uniform state in which the solid content concentration is locally different from other parts such as precipitation, phase separation or skinning in the aqueous dispersion. It is obtained by.

  The volume average particle size of the aqueous dispersion needs to be 300 nm or less, preferably 200 nm or less, and more preferably 150 nm or less. When the volume average particle size is larger than 300 nm, the copolymerized polyester resin in the obtained aqueous dispersion immediately settles and storage stability cannot be obtained, which is not preferable. By using the production method described above, the volume average particle diameter of the aqueous dispersion can be adjusted to the above range by controlling the amount of the basic compound, the phase inversion temperature, and the like.

  In the production of the aqueous dispersion, a filtration step may be provided in the process for the purpose of removing foreign substances and the like. In such a case, for example, a stainless steel filter (wire diameter: 0.035 mm, plain weave) of about 300 mesh may be installed and pressure filtration (air pressure 0.2 MPa) may be performed.

  Next, a method for using the aqueous dispersion of the present invention will be described.

  Since the aqueous dispersion of the present invention is excellent in film forming ability, it can be uniformly coated on the surface of various substrates by known film forming methods such as dipping method, brush coating method, spray coating method, curtain flow coating method and the like. Then, after setting it at around room temperature as necessary, it is subjected to heat treatment for drying and baking, whereby a uniform resin film can be formed in close contact with the surfaces of various substrates. As a heating device at this time, a normal hot air circulation type oven, an infrared heater, or the like may be used. In addition, the heating temperature and the heating time are appropriately selected depending on the type of the substrate to be coated and the like, but considering the economy, the heating temperature is preferably 90 to 250 ° C., 90 -230 degreeC is more preferable, 100-200 degreeC is especially preferable, As heating time, 1 second-30 minutes are preferable, 5 seconds-20 minutes are more preferable, and 10 seconds-10 minutes are especially preferable.

  The thickness of the resin film formed using the aqueous dispersion of the present invention is appropriately selected depending on the purpose and application, but is preferably 0.01 to 40 μm, more preferably 0.1 to 30 μm. 0.5 to 20 μm is particularly preferable.

  Further, the aqueous dispersion of the present invention includes a curing agent, various additives, pigments such as titanium oxide, zinc white, and carbon black, dyes, other aqueous polyester resins, aqueous urethane resins, aqueous olefin resins, as necessary. An aqueous resin such as an aqueous acrylic resin can be blended.

  The curing agent is not particularly limited as long as it is a functional group possessed by the copolymer polyester resin, such as a carboxyl group or its anhydride and a hydroxyl group, and is not particularly limited. For example, a urea resin, a melamine resin, or a benzoguanamine resin. Such as amino resins, polyfunctional epoxy compounds, polyfunctional isocyanate compounds and their various blocked isocyanate compounds, polyfunctional aziridine compounds, carbodiimide group-containing compounds, oxazoline group-containing polymers, phenol resins, etc., one of these You may use 2 or more types together.

  Examples of additives include repellency inhibitors, leveling agents, antifoaming agents, anti-waxing agents, rheology control agents, pigment dispersants, ultraviolet absorbers, and lubricants.

  The curing agent, various additives, pigments, dyes, aqueous resins, and the like described above may be added in advance when the polyester resin is dissolved or dispersed.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

1. Measuring method

(Characteristics of copolymer polyester resin)

(1) Composition of copolymerized polyester resin The composition was determined by ¹ H-NMR analysis using a nuclear magnetic resonance apparatus (300 MHz) manufactured by Varian.

(2) Number average molecular weight of copolymerized polyester resin The number average molecular weight was measured by GPC analysis (using liquid feeding unit LC-10ADvp type and UV-visible spectrophotometer SPD-6AV type, detection wavelength: 254 nm, solvent: Shimadzu Corporation) Tetrahydrofuran, polystyrene conversion).

(3) Tg of copolymer polyester resin
Using a copolymer polyester resin 10 mg as a sample, a differential scanning calorimeter (DSC7 type) manufactured by PerkinElmer Co., Ltd. is used to measure at a temperature rising rate of 10 ° C./min. The intermediate value between the two derived bending point temperatures was defined as Tg.

(4) Acid value of copolymerized polyester resin 0.5 g of polyester resin was dissolved in 50 ml of water / dioxane = 1/9 (volume ratio), titrated with KOH using cresol red as an indicator, and consumed for neutralization. A value obtained by converting the number of mg of KOH per 1 g of the polyester resin was determined as an acid value.

(5) Content of copolymer polyester resin in aqueous dispersion An appropriate amount of the aqueous dispersion was weighed and heated at 150 ° C. until the mass of the residue (solid content) reached a constant weight, thereby solidifying the aqueous dispersion. The partial concentration was determined.

(Characteristics of aqueous dispersion of copolymer polyester resin)

(6) Content of organic solvent in aqueous dispersion Using gas chromatograph (GC-8A type; using FID detector) manufactured by Shimadzu Corporation, carrier gas: nitrogen, column packing material (manufactured by GL Sciences): PEG- HT (5%)-UNIPORT HP (60/80 mesh), column size: diameter 3 mm × 3 m, sample charging temperature (injection temperature): 150 ° C., column temperature: 60 ° C., internal standard: n-butanol Then, the aqueous dispersion diluted with water was directly put into the apparatus, and the content of the organic solvent was determined. The detection limit was 0.01% by mass.

(7) Volume average particle diameter of aqueous dispersion The aqueous dispersion was diluted with water to 0.1% by mass, and the volume average particle was measured with a particle size distribution measuring apparatus “MICROTRACK UPA” (9340-UPA type) manufactured by Nikkiso Co., Ltd. The diameter was measured.

(8) Storage stability of aqueous dispersion 30 ml of the aqueous dispersion was placed in a 50 ml glass sample bottle, and the appearance change after storage at 25 ° C. for 60 days was visually observed.

(Characteristics of resin coating)

(9) Adhesiveness of resin coating Using a tabletop coating device (film applicator No. 542-AB type; bar coater mounted) manufactured by Yasuda Seiki, an aqueous aqueous dispersion is coated on the substrate, and the temperature is set to 130 ° C. By heating in an oven for 1 minute, a resin film having a thickness of about 1 μm was formed on the substrate, and then the end of the adhesive tape (width 18 mm) defined in JIS Z1522 was left on this resin film. After sticking and rubbing with an eraser from the top, the adhesive tape was peeled off instantaneously after making the end of the adhesive tape perpendicular to the film. By analyzing the peeled surface of the adhesive tape with a surface infrared spectroscope manufactured by PerkinElmer (SYSTEM2000 type; using a Ge60 ° 50 × 20 × 2 mm prism), whether or not a resin film is attached to the surface of the adhesive tape. The adhesion of the resin film to the substrate was evaluated according to the following criteria. As the substrate, a biaxially stretched PET film (manufactured by Unitika Ltd., thickness 12 μm) was used.
○: No peak derived from the resin film is observed on the adhesive tape surface.
X: A peak derived from the resin film is observed on the adhesive tape surface.

(10) Hot water resistance of resin film Using a desktop coating apparatus, the aqueous dispersion is coated on the above biaxially stretched PET film and heated in an oven set at 160 ° C. for 1 minute to obtain a thickness of about After forming a 1 μm resin film, the PET film on which this resin film was formed was partially immersed in boiling water, gently pulled up after 4 hours, and air-dried, and then the appearance of the resin film was visually observed. Observed and evaluated according to the following criteria.
○: No change in appearance was observed.
X: Partial whitening or dissolution is observed.

(11) Solvent resistance of resin film Using a tabletop coating apparatus, an aqueous dispersion is coated on the above biaxially stretched PET film and heated in an oven set at 180 ° C. for 1 minute to obtain a thickness. After forming a resin film of about 1 μm, the PET film on which this resin film was formed was partially immersed in ethanol at room temperature, gently pulled up after 10 minutes, and air-dried. It observed visually and evaluated by the following reference | standard.
○: No change in appearance was observed.
X: Partial whitening or dissolution is observed.

(Manufacture of copolyester resin)

Production Example 1
A mixture comprising 1661 g (100 mol parts) of terephthalic acid, 586 g (77 mol parts) of 1,2-propanediol, 1066 g (73 mol parts) of isosorbide (manufactured by Rocket), and 2.7 g (0.2 mol parts) of trimellilol propane. Then, 1.3 g of hydroxybutyltin oxide was added as a catalyst, and the esterification reaction was carried out by heating at 240 ° C. for 3 hours in an autoclave while stirring. Next, the temperature was raised to 270 ° C., 3.4 g of tetrabutyl titanate was added as a catalyst, the pressure of the system was gradually reduced to 13 Pa after 1.5 hours, and a polycondensation reaction was performed. After 4 hours, the system was brought to atmospheric pressure with nitrogen gas, the temperature of the system was lowered, and when it reached 260 ° C, 6.3 g (0.3 mol) of trimellitic anhydride was added and stirred at 260 ° C for 2 hours. A depolymerization reaction was performed. Thereafter, the pressure of the system was gradually reduced to 6700 Pa after 0.5 hours, and defoaming reaction was performed for 0.5 hours. Thereafter, the system is pressurized with nitrogen gas, the resin is discharged in a strand shape, cooled with water, and cut to obtain a copolyester resin (P-1) in a pellet form (diameter: about 3 mm, length: about 3 mm). Obtained. The copolymer polyester resin (P-1) had a number average molecular weight of 9000, a glass transition temperature of 131 ° C., and an acid value of 3.0 mgKOH / g. Table 1 shows the resin composition, characteristic values, and results of solubility evaluation.

Production Example 2
A mixture of 1495 g (90 mol parts) of terephthalic acid, 166 g (10 mol parts) of isophthalic acid, 1104 g (145 mol parts) of 1,2-propanediol, and 73 g (5 mol parts) of isosorbide (Rocket) was stirred. However, a copolymerized polyester resin (P-2) was obtained in the same manner as in Example 1 except that the esterification reaction was performed by heating at 240 ° C. for 3 hours in an autoclave. Table 1 shows the final resin composition and characteristic values of the obtained polyester resin (P-2).

Production Examples 3 to 11
The monomer used and the charged molar part were changed, and the same operation as in Production Example 1 was performed to obtain a copolyester resin (P-3) to a copolyester resin (P-11). Table 1 shows the final resin compositions and characteristic values of the obtained copolyester resins (P-3) to (P-11).

Example 1
[Dissolution process]
400 g of copolyester resin (P-1) (acid value: 3.0 mgKOH / g) and 600 g of cyclohexanone are charged into a 3 L polyethylene container, and the container is heated with hot water of about 80 ° C., and manufactured by Tokyo Rika Co., Ltd. The copolymer polyester resin was completely dissolved in cyclohexanone by stirring using a stirrer (MAZELA1000 type) to obtain a copolymer polyester resin solution having a solid content concentration of 40% by mass.
[Dispersion process]
Immediately after dissolution, the solution is cooled to 15 ° C., and 500 g of the above-mentioned copolymerized polyester resin solution is charged into a jacketed glass container (internal volume 2 L), and the system temperature is kept at about 15 ° C. Stirring was performed with a stirrer (MAZELA1000 type) (rotation speed: 600 rpm). Next, with stirring, 16.2 g of triethylamine (an equivalent ratio of 15 times the total amount of carboxyl groups of the copolyester resin) was added as a basic compound, followed by distillation at about 15 ° C. at a rate of 100 g / min. 1984 g of water was added. The temperature of the aqueous dispersion after completion of the addition was about 15 ° C., and the mixture was stirred for 30 minutes while maintaining about 15 ° C. to obtain an aqueous dispersion.
[Desolvation process]
Subsequently, 300 g of the obtained aqueous dispersion and 245 g of distilled water were placed in a 2 L flask, and the rotary evaporator (N-1100V-) manufactured by Tokyo Rika Co., Ltd. was adjusted at a reduced pressure of 100 mmHg while adjusting the internal temperature to 80 ° C. or lower. (WD type) was used for solvent removal. The solvent removal was completed when the amount of distilled water reached about 360 g, and the mixture was cooled to room temperature and filtered through a 300 mesh stainless steel filter. Subsequently, after measuring the solid content concentration of this aqueous dispersion, distilled water was added so that the solid content concentration would be 30% by mass to obtain an aqueous dispersion. The obtained aqueous dispersion had a volume average particle diameter of 138 μm, good storage stability, and good adhesion, hot water resistance and solvent resistance of the resin coating. The results are shown in Table 2.

Example 2
[Dissolution process]
Into a 3 L polyethylene container, 400 g of copolyester resin (P-2) (acid value 3.0 mgKOH / g) and 600 g of 2-butanone are added. A container with a reflux tube is added and heated with hot water of about 80 ° C. While stirring using a stirrer (MAZELA1000 type) manufactured by Tokyo Rika Co., Ltd., the copolyester resin was completely dissolved in 2-butanone to obtain a copolyester resin solution having a solid content concentration of 40% by mass. .
[Dispersion process]
Immediately after dissolution, the solution is cooled to 15 ° C., and 500 g of the above-mentioned copolymerized polyester resin solution is charged into a jacketed glass container (internal volume 2 L), and the system temperature is kept at about 15 ° C. Stirring was performed with a stirrer (MAZELA1000 type) (rotation speed: 600 rpm). Next, 10.8 g of triethylamine (equivalent ratio of 10 times the total amount of carboxyl groups of the copolyester resin) was added as a basic compound with stirring, and then distilled at about 15 ° C. at a rate of 100 g / min. 1989 g of water was added. The temperature of the aqueous dispersion after completion of the addition was about 15 ° C., and the mixture was stirred for 30 minutes while maintaining about 15 ° C. to obtain an aqueous dispersion.
[Desolvation process]
Subsequently, 300 g of the obtained aqueous dispersion and 5 g of distilled water were placed in a 2 L flask, placed in an oil bath at 120 ° C., and the solvent was removed at normal pressure. Solvent removal was completed when the amount of distilled solvent reached about 120 g, cooled to room temperature, and filtered through a 300 mesh stainless steel filter. Subsequently, after measuring the solid content concentration of this aqueous dispersion, distilled water was added so that the solid content concentration would be 30% by mass to obtain an aqueous dispersion. The evaluation results are shown in Table 2.

Example 3
[Dissolution process]
Into a 3 L polyethylene container, 500 g of copolyester resin (P-3) (acid value 3.5 mgKOH / g) and 500 g of toluene / 2-butanone = 1/1 (mass ratio) are charged. Then, while heating with hot water of about 80 ° C., it is a copolymer polyester resin so as not to completely change the ratio of toluene and 2-butanone by stirring using a stirrer (MAZELA1000 type) manufactured by Tokyo Rika Co., Ltd. Was dissolved in toluene / 2-butanone = 1/1 (mass ratio) to obtain a polyester resin solution having a solid content concentration of 50 mass%.
[Dispersion process]
Immediately after dissolution, the solution is cooled to 15 ° C., and 500 g of the above-mentioned copolymerized polyester resin solution is charged into a jacketed glass container (internal volume 2 L), and the system temperature is kept at about 15 ° C. Stirring was performed with a stirrer (MAZELA1000 type) (rotation speed: 600 rpm). Next, 31.6 g of triethylamine (an equivalent ratio of 25 times the total amount of carboxyl groups of the copolymerized polyester resin) was added as a basic compound with stirring, followed by distillation at about 15 ° C. at a rate of 100 g / min. 1968 g of water was added. The temperature of the aqueous dispersion after completion of the addition was about 15 ° C., and the mixture was stirred for 30 minutes while maintaining about 15 ° C. to obtain an aqueous dispersion.
[Desolvation process]
Subsequently, 300 g of the obtained aqueous dispersion and 156 g of distilled water were placed in a 2 L flask, placed in an oil bath at 120 ° C., and the solvent was removed at normal pressure. Solvent removal was completed when the amount of distilled water reached about 225 g, and after cooling to room temperature, the mixture was filtered through a 300 mesh stainless steel filter. Subsequently, after measuring the solid content concentration of this aqueous dispersion, distilled water was added so that the solid content concentration would be 30% by mass to obtain an aqueous dispersion. The evaluation results are shown in Table 2.

Examples 4 and 7
An aqueous dispersion was obtained in the same manner as in Example 1 except that the equivalent ratio of the copolymerized polyester resin and the copolymerized polyester resin to the total amount of carboxyl groups was changed. The evaluation results are shown in Table 2.

Examples 5, 6, and 8
An aqueous dispersion was obtained in the same manner as in Example 2 except that the equivalent ratio of the copolyester resin and the copolyester resin to the total carboxyl group amount was changed. The evaluation results are shown in Table 2.

Example 9
An aqueous dispersion was obtained in the same manner as in Example 2 except that the basic compound was changed to 14.3 g of dimethylaminoethanol instead of triethylamine. The evaluation results are shown in Table 2.

Examples 10, 11, 12
An aqueous dispersion was obtained in the same manner as in Examples 1, 3, and 4 except that the solvent removal step in Examples 1, 3, and 4 was not performed. The evaluation results are shown in Table 2.

Comparative Example 1
Except for phase inversion emulsification without adding triethylamine, the same procedure as in Example 2 was carried out. However, in the transfer emulsification step, the copolymerized polyester resin was entangled with stirring blades during the addition of distilled water, and an aqueous dispersion was not obtained. It was. The evaluation results are shown in Table 2.

Comparative Example 2
The same procedure as in Example 2 was conducted except that the amount of triethylamine was 1.6 g (equivalent ratio of 1.5 times the total amount of carboxyl groups of the copolyester resin), but the amount of basic compound was small. Therefore, the volume average particle diameter of the obtained aqueous dispersion became 400 nm, and when left for about one week, precipitation occurred, and an aqueous dispersion with good storage stability could not be obtained. The evaluation results are shown in Table 2.

Comparative Example 3
Example except that the amount of triethylamine was changed to 43.3 g (equivalent ratio of 40 times the total carboxyl group amount of the copolyester resin), and the distilled water added in the dispersion step was changed to 1957 g. The procedure was the same as in Example 2, but the amount of the basic compound was larger than the amount specified in the formula (1), so that the working environment became very bad due to the triethylamine odor, and copolymerization was carried out at the time of solvent removal. The polyester resin aggregated and could not be removed. The evaluation results are shown in Table 2.

Comparative Example 4
The copolyester resin was prepared in the same manner as in Example 2 except that (P-9) was used instead of (P-2), but the glass transition temperature of the copolyester resin used was low. Therefore, there was no problem until about 2 hours, but when immersed in hot water for 4 hours, it was partially whitened and the hot water resistance was poor. The evaluation results are shown in Table 2.

Comparative Example 5
The copolymer polyester resin was prepared in the same manner as in Example 2 except that (P-10) was used instead of (P-2), but the acid value of the copolymer polyester resin used was low. In addition, in the transfer emulsification step, the copolymerized polyester resin was entangled with the stirring blades during the addition of distilled water, and an aqueous dispersion could not be obtained. The evaluation results are shown in Table 2.

Comparative Example 6
As the copolyester resin, except that (P-11) was used instead of (P-2), it was carried out in the same manner as in Example 2, but the acid value of the copolyester resin used was high, Since the molecular weight was low, adhesion, hot water resistance, and solvent resistance all deteriorated.

  The aqueous dispersions of Examples 1 to 12 had a glass transition temperature as high as 85 ° C. or higher, and the coating film had good adhesion, hot water resistance, and solvent resistance. The evaluation results are shown in Table 2.

Since Comparative Examples 1 to 6 were carried out outside the specified range of the present invention, even if an aqueous dispersion was not obtained or an aqueous dispersion was obtained, the characteristic values were unsuitable.

Claims (3)

The following components (A) to (D) are blended, and a copolymer polyester resin aqueous dispersion in which fine particles of the copolymer polyester resin are uniformly dispersed in an aqueous medium, A copolymer polyester resin aqueous dispersion, wherein the content of the polymerized polyester resin is 5 to 50% by mass, and the volume average particle diameter of the copolymerized polyester resin is 300 nm or less.
(A) mainly composed of a dicarboxylic acid component and a glycol component, including an aromatic dicarboxylic acid as the dicarboxylic acid component, isosorbide as the glycol component, an acid value of 2 to 12 mg KOH / g, and a glass transition temperature of 85 ° C. or higher, A copolymerized polyester resin having a number average molecular weight of 4000 or more.
(B) 0-25 mass% of basic compound (C) organic solvent.
(D) Water 2. The method for producing an aqueous copolymer polyester resin dispersion according to claim 1, wherein the copolymer polyester resin is dissolved in an organic solvent and then mixed and dispersed with water and a basic compound. A copolymer polyester resin film obtained from the aqueous copolymer polyester resin dispersion according to claim 1.