GB2097005A - Polyester resin aqueous dispersion - Google Patents

Abstract

An aqueous dispersion of polyester resin which comprises (A) a crystalline polyester having a melting point in the range of from 70 to 200 DEG C and containing from 0.5 to 10% by mole of an aromatic dicarboxylic acid containing a metal sulfonate group as the polycarboxylic acid component, (B) a noncrystalline polyester having a softening point in the range of from 40 to 200 DEG C and containing from 0.5 to 10% by mole or an aromatic dicarboxylic acid containing metal sulfonate group as the polycarboxylic acid component, (C) a water-soluble organic compound having a boiling point in the range of from to 200 DEG C, and (D) water, the components (A), (B), (C) and (D) being incorporated in the dispersion in the following weight ratios: (1) A/B = 0-95/100-5 (2) A+B/C/D = 10-70/2-40/20-88 (3) 0.02 </= C/C+D </= 0.66 The aqueous dispersion of this invention has an excellent dispersibility in water and can provide coating layers having an excellent water resistance and weatherability and hence is useful for preparation of various laminated products, coating compositions, aqueous printing inks, aqueous binders for coating purposes and surface treating agents.

Description

SPECIFICATION Polyester resin aqueous dispersion The present invention relates to an aqueous polyester resin dispersion, more particularly an aqueous dispersion of a polyester resin having a fine particle size which can provide coating films having an excellent water resistance and excellent weatherability.

Hitherto, large amounts of various organic solvents have been widely used in various fields such as paints, ink, coating compositions, adhesives and treating agents for textile or paper products. Recently, however, it has become very difficult to use large amounts of organic solvents in view of the necessity to save oil resources and to prevent environmental pollution. Accordingly, it has been proposed to prepare the above-mentioned compositions in non-organic solvent, such as (1) high solids compositions (2) non-aqeuous dispersion compositions, (3) aqueous dispersion compositions, (4) emulsion compositions, and (5) non-solvent compositions. Of these, the aqueous dispersion type compositions are the most useful because of easy handling.

However, the conventional resins used in the preparation of these compositions are mostly hydrophobic, and hence, it is a problem to disperse them in water or to make them compatible with water. Moreover, the resin aqueous dispersions can provide coating films having an excellent water resistance and an excellent weatherability. These problems are common in all resins including polyester resins.

Some methods for dispersing polyester resins in water or for making them compatible with water have already been proposed, for example by copolymerizing them with hydrophilic monomers, such as a compound having a metal sulfonate group, an aliphatic dicarboxylic acid, or a mixture thereof. However, these hydrophilic monomers have to be used in a large amount in order to give the polyester resins sufficient water-dispersibility or water-compatibility, and furthermore, the resulting aqueous dispersion of polyester resins merely gives a coating film having an inferior water resistance and weatherability and inferior adhesion properties.

For example, Japanese Patent Publication No. 40873/1972 discloses that in order to sufficiently disperse the resins in water, 8% by mole or more (based on the total acid components) of a compound containing a metal sulfonate group and 20% by mole or more (based on the total glycol components) of polyethylene glycol are required. It will readily be understood that such polyester resins show inferior water resistance and weatherability. That is, when a resin has a sufficient dispersibility in water, it results in an inferior water resistance of the coating film prepared on coating the resin aqueous dispersion, followed by drying. In this case, when the formed coating film is contacted with water, it shows a decreased adhesion and colour change. Accordingly, such a resin can not be used for the preparation of paints, inks, coating compositions and adhesives.Furthermore, when a large amount of polyethylene glycol is used, the resulting resin shows a significantly decreased water resistance and weatherability.

It is also well known that when a large amount of an aliphatic dicarboxylic acid is copolymerized, the resulting polyester resin possesses inferior properties, such as inferior mechanical properties.

Thus, any particularly useful resin should satisfy both the requirements of hydrophilic properties and water resistance and weatherability.

We have now developed an improved aqueous polyester resin dispersion which does not have a decreased water resistance and weatherability which comprises one or two kinds of specific polyester containing a metal sulfonate group, a water-soluble organic compound and water.

Accordingly, the present invention provides an aqueous dispersion of a polyester resin which comprises: (A) a crystallaine polyester having a melting point in the range of from 70 to 2000C and containing from 0.5 to 10% by mole of an aromatic dicarboxylic acid containing a metal sulfonate group as the polycarboxylic acid component, (B) a non-crystalline (i.e. amorphous) polyester having a softening point in the range of from 40 to 2000C and containing from 0.5 to 10% by mole of an aromatic dicarboxylic acid containing a metal sulfonate group as the polycarboxylic acid component, (C) a water-soluble organic compound having a boiling point in the range of from 70 to 2000C, and (D) water, the components (A), (B), (C) and (D) being incorporated in the dispersion in the following weight ratios:: (1) A/B = 0--95/1 00--5 (2) A+B/C/D = 10-70/2-40/20-88 (3) 0.02 < C/C+D < 0.66.

By incorporating (A) a crystalline polyester resin containing a metal sulfonate group, (B) a noncrystalline polyester resin containing a metal sulfonate group, (C) a water-soluble organic compound having a boiling point in the range of from 70 to 2000C, and (D) water in the specified weight ratio, an aqueous dispersion is obtained having both hydrophilic properties and high adhesion and water resistance. The aqueous dispersion thus obtained has a particle size of 1 y or less and is very stable.

The aqeuous polyester resin dispersion has various utilities such as in coating compositions, laminated products, aqueous printing inks, aqueous binders for coating, and surface treating agents.

The crystalline and non-crystalline polyester resins contain from 0.5 to 10% by mole of an aromatic dicarboxylic acid having a metal sulfonate group as the polycarboxylic acid component.

Preferably, the crystalline and non-crystalline polyester resins have a molecular weight in the range of from 2,500 to 30,000 and comprise polycarboxylic acid components consisting of 40 to 99.5% by mole of an aromatic dicarboxylic acid containing no metal sulfonate group, 59.5 to 0% by mole of an aliphatic or alicyclic dicarboxylic acid containing 4 to 36 carbon atoms and 0.5 to 10% by mole of an aromatic dicarboxylic acid containing a metal sulfonate group, and polyol components consisting of 20 to 100% by mole of an aliphatic glycol containing 2 to 8 carbon atoms and/or an alicyclic glycol having 6 to 12 carbon atoms and 80 to 0% by mole of bisphenol A ethylene oxide (or propylene oxide) adduct.

Examples of the aromatic dicarboxylic acid containing no metal sulfoate group are terephthalic acid, isophthalic acid, orthophthalic acid and 2,6-naphthalene-dicarboxylic acid. These aromatic dicarboxylicacid are preferably incorporated in an amount of 40 to 99.5% by mole based on the total polycarboxylic acid components. When the content of the aromatic dicarboxylic acid containing no metal sulfonate group is less than 40% by mole, the polyester resin thus obtained has an inferior mechanical strength and inferior water resistance, and, on the other hand, when the content is above 99.5% by mole, the polyester resin can hardly be dispersed into the aqueous system.

Examples of the aliphatic or alicyclic dicarboxylic acid are succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedionic acid, dimer acid tetrahydrophthalic acid, hexahydrophthalic acid, hexahydroisophthalic acid and hexahydroterephthalic acid. Particularly preferred are adipic acid, sebacic acid and azelaic acid. The aliphatic and/or alicyclic dicarboxylic acids are preferably incorporated in an amount of 59.5 to 0% by mole based on the total polycarboyxlic acid components. When the amount of the aliphatic and/or alicyclic dicarboxylic acid is above 59.5% by mole, the polyester resin obtained shows a decreased water resistance and mechanical strength of the coating film prepared therefrom, and shows tackiness.Optionally, p-hydroxy-benzoic acid, p(2-hydroxyethoxy) benzoic acid, or hydroxy pivalic acid, cg-butyrolacetone or E-caprolactone may be incorporated as the polycarboxylic acid component. Moreover, tri- or higher polyvalent polycarboxylic acids, such as trimellitic acid or pyromellitic acid, may optionally be incorporated in an amount of not more than 10% by mole, usually 0.01 to 10% by mole based on the total polycarboxylic acid components.

Examples of the aliphatic glycol containing 2 to 8 carbon atoms are ethylene glycol, propylene glycol, 1 ,3-propanediol, 1 ,4-butanediol, neopentyl glycol, 1 ,5-pentanediol and 1,6-hexanediol. An example of the alicyclic glycol containing 6 to 12 carbon atoms is 1 ,4-cyclohexane-dimethanol. These aliphatic glycols containing 2 to 8 carbon atoms and alicyclic glycol containing 6 to 1 2 carbon atoms are incorporated in an amount of 90 to 100% by mole based on the total polyol components. Optionally, tri- or more polyvalent polyols such as tri-methylolpropane, trimethylolethane, glycerine or pentaerythritol may be incorporated in an amount of not more than 10% by mole, usually 0.01 to 10% by mole, based on the total polyol components.Moreover, polypropylene glycol or polytetramethylene glycol having a molecular weight of 500 to 5,000 may optionally be incorporated in an amount of not more than 40% by weight, usually 0.01 to 40% by weight, based on the total polyol components.

Furthermore, a polyalkylene glycol, particularly a polyethylene glycol having a molecular weight of 106 to 10,000 may optionally be incorporated in an amount of not more than 10% by weight, preferably 0.01 to 5% by weight, based on the total polyol components. When the polyalkylene glycol, particularly polyethylene glycol, is incorporated in an amount of above 10% by weight, the polyester resin shows an extremely decreased water resistance and weatherability. A suitable crystalline polyester comprises 50 to 99.5% by mole of terephthalic acid or isophthalic acid as the polycarboxylic acid component and 85 to 100% by mole of ethylene glycol and butanediol as the polyol component.Furthermore, a suitable non-crystalline polyester comprises 40 to 60% by mole of terephthalic acid as the polycarboxylic acid component and 20 to 60% by mole of ethylene glycol or butanediol as the polyol component.

Suitable examples of the aromatic dicarboxylic acid containing a metal sulfonate group are metal salts of sulfo-aromatic dicarboxylic acids, such as sulfoterephthalic acid, 4-sulfo-isophthalic acid, 4sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid or 5-(4-sulfophenoxy) isophthalic acid.

The metal salts include salts of metals such as lithium (Li,) sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), copper (Cu) or iron (Fe). Particularly, preferred is 5-sodium sulfoisophthalic acid. The aromatic di-carboxylic acids containing a metal sulfonate group are incorporated in an amount of 0.5 to 10% by mole, preferably 1.0 to 6% by mole, based on the total polycarboxylic acid components. When the aromatic dicarboxylic acid containing a metal sulfonate group is not entirely incorporated, the polyester resin obtained shows a remarkably inferior dispersibility in water. With an increase in the amount of aromatic dicarboxylic acid containing a metal sulfonate group, the polyester resin obtained shows a better dispersibility into water. However, when the amount of the aromatic dicarboxylic acid containing a metal sulfonate group is over 10% by mole, the polyester resin gives a coating film having a remarkably inferior water resistance, while the dispersibility in water is excellent.

The crystalline polyester resin used in the present invention has a melting point in the range of 70 to 2000C, preferably 90 to 1 800 C. When the crystalline polyester resin has a melting point below 700 C, the polyester resin aqueous dispersion gives a coating film having an inferior water resistance, and on the other hand, when the melting point is above 2000 C, the polyester resin shows less dispersibility in water. Furthermore, the crystalline polyester resin should preferably have a heat of fusion of 50 cal or more, more preferably 100 to 1,500 cal, per polymer unit. When it has a heat of fusion of less than 50 cal per polymer unit, the polyester resin shows an inferior water resistance, particularly an inferior resistance to hot water.

The non-crystalline polyester resin used in the present invention has a softening point of 40 to 2000 C, preferably 60 to 1800 C. When the softening point of the non-crystalline polyester resin is below 400C, the aqueous polyester resin dispersion gives a coating film having an inferior water resistance and having an unfavourable tackiness, and on the other hand, when the softening point is above 2000C, the polyester resin shows an inferior dispersibility in water.

The crystalline and non-crystalline polyester resins preferably have a molecular weight of 2,500 to 30,000, preferably 3,000 to 20,000. When the polyester resins have a molecular weight below 2,500, the aqueous polyester resin dispersion shows an inferior water resistance and inferior adhesion properties, and also inferior mechanical properties, especially inferior flexibility, and on the other hand, when the molecular weight is above 30,000 the polyester resins shows an inferior dispersibility into water, and furthermore, it is difficult to incorporate the resins into the aqueous dispersion in a large amount because the aqueous dispersion thereof possesses too high a viscosity.

The polyester resins may be produced by any conventional methods. The polyester resins may optionally be used after being mixed with an amino resin, an epoxy compound or an isocyanate compound in the molten state of in the form of a solution in a water-soluble organic compound, or may be used in the form of a partial reaction product with the above-mentioned amino resin, epoxy compound or isocyanate compound.

The water-soluble organic compound used in the present invention is used to increase the hydrophilic properties of the polyester resins and thereby promote its dispersibility into water. Thus, when the polyester resins, a small amount of the water-soluble organic compound and water are mixed, the desired aqueous dispersion can be obtained.

The water-soluble organic compounds generally have a solubility of 20 g or more/l liter of water at 200C and include aliphatic and alicyclic alcohols, ethers, esters and ketones. Examples of the watersoluble organic compounds are monovalents alcohols such as ethanol, n-propanol, isopropanol, nbutanol, isobutanol, sec-butanol, tert-butanol; glycols such as ethylene glycol, propylene glycol; glycol derivatives such as methyl cellosolve, ethyl cellosolve, n-butyl cellosolve, 3-methyl-3-methoxybutanol, n-butyl-cellosolve acetate; ethers such as dioxane, esters such as ethyl acetate; and ketones such as methyl ethyl ketone, cyclohexanone, cyclooctanone, cyclodecanone, isophorone. Particularly preferred examples are n-butyl cellosolve, ethyl cellosolve and isopropanol. These water-soluble organic compounds may be used alone or as a mixture of two or more thereof.The water-soluble organic compounds have a boiling point of from 70 to 2000C. When the organic compounds have a boiling point of below 700 C, it is very difficult to maintain the temperature necessary for uniformly dispersing or dissolving the polyester resins in the water-soluble organic compound, and on the other hand, when the boiling point is above 2000 C, the aqueous dispersion hardly dries when coated, and further the aqueous dispersion shows less storage stability as well as inferior drying properties when an amide or sulfonate compound is used as the water-soluble compound.

The aqueous dispersion of the present invention is prepared by previously mixing a crystalline polyester resin (A), a non-crystalline polyester resin (B) and a water-soluble organic compound (C) at 50 to 2000C and adding thereto water (D), or by adding a mixture of the components (A), (B) and (C) to water (D), followed by agitating the mixture at 40 to 120DC. Alternatively, the aqueous dispersion may be prepared by adding the polyester resins (A) and (B) to a mixture of a water-soluble organic compound (C) and water (D), followed by agitating the mixture at 40 to 100 C. In any of these methods, the components: a crystalline polyester resin (A), a non-crystalline polyester resin (B), a water-soluble organic compound (C) and water (D) should preferably be incorporated in the following weight ratio in order to obtain the desired properties of the aqueous dispersion: (1) A/B = 0-95/100-5 (2) A+B/C/D = 10-70/2-40/20-88 (3) 0.02~C/C+D~0.66.

The aqueous dispersion of the present invention contains the non-crystalline polyester resin (B) alone or both of the crystalline polyester resin (A) and the non-crystalline polyester resin (B), but the crystalline polyester resin (A) is preferably contained in an amount of 1% by weight or more based on the weight of the total polyester resins because the aqueous dispersion can give a coating film having greater water resistance, particularly resistance to hot water. On the other hand, when the crystalline polyester resin (A) is contained in an amount of above 95% by weight, the polyester resins show inferior dispersibility in water.

When the polyester resins (A) and (B) are incorporated in an amount of less than 10% by weight or more than 70% by weight based on the total weight of the aqueous dispersion, the aqueous dispersion show an unfavourably too low or too high viscosity, respectively.

When the water-soluble organic compound (C) is incorporated in an amount of less than 2% by weight based on the total weight of the aqueous dispersion, it results in less dispersibility of the polyester resins and the desired stable aqueous dispersion having a particle size of less than 1 y can not be obtained. On the other hand, when the water-soluble organic compound is incorporated in an amount of above 40% by weight, the aqueous dispersion shows unfavourably inferior drying properties.

Particularly preferred amounts of the water-soluble organic compound (C) are in the range of 2.5 to 30% by weight based on the total weight of the aqueous dispersion.

The aqueous dispersion of the present invention may be used for various purposes as it stands, but may be used after being mixed with one or more crosslinking agents such as amino resins, epoxy compounds and isocyanate compounds.

Examples of the amino resins are the formaldehyde adduct of urea, melamine or benzoguanamine, and alkylated producted thereof with an alcohol having 1 to 6 carbon atoms, which may optionally be used together with formaline to give a preferred effect.

Examples of the epoxy compounds are polyglycidyl esters and ethers, such as the diglycidyl ether of bisphenol A or its oligomer, diglycidyl ether of hydrogenated bisphenol A or its oligomer, diglycidyl orthophthalate, diglycidyl isophthalate, diglycidyl terephthalate, p-hydroxylbenzoic acid glycidyl ester ether, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl succinate, diglycidyl adipate, diglycidyl sebacate, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4butanediol diglycidyl ether, 1 ,6-hexanediol diglycidyl ether, and other polyalkylene glycol diglycidyl ethers, triglycidyl trimellitate, triglycidyl isocyanurate, 1 ,4-diglycidyloxybenzene, diglycidylmethylhydantoin, diglycidylethyleneurea, di-glycidylpropyleneurea, glycerol polyglycidyl ether, tri-methylolethane polyglycidyl ether, trimethylolpropene polyglycidyl ether, pentaeryth ritol polyglycidyl ether or the polyglycidyl ether or glycerol alkylene oxide adduct.

The isocyanate compounds include aromatic, aliphatic and araliphatic diisocyanates, tri- or more higher polyvalent polyisocyanates, which may be low molecular weight or high molecular weight compounds. Examples of the isocyanate compounds are tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, trimer of isophorone diisocyanate, or compounds having terminal isocyanate group which are obtained by reacting an excess amount of the above-mentioned isocyanate compounds with low molecular active hydrogen compounds such as ehtylene glycol, propylene glycol, trimethylol-propane, glycerine, sorbitol, ethylenediamine, monoethyanolamine, diethanolamine, or triethanolamine; or high molecular active hydrogen compounds such as various polyether polyols, polyester polyols, or polyamides.

The isocyanate compounds may be blocked isocyanate compounds which are prepared by subjecting the above-mentioned isocyanate compounds to an addition reaction with a blocking agent.

Suitable examples of the blocking agent are phenols such as phenol, thiophenol, methylthiophenol, ehtylphenol, cresol, xylenol, resorcinol, nitrophenol, chlorophenol; oximes such as acetoxime, methyl ethyl ketoxime, cyclohexanone oxime; primary alchols such as methanol, ethanol, propanol, butanol; halogeno-alcohols such as ethylene chlorohydrin, 1 ,3-dichloro-2-propanol; tertiary alcohols such as tert-butanol, tert-pentanol, tert-butanethiol; lactams such as E-caprolactam, 8-valemlactam, ar- butylactam, p-propiolactam, aromatic amines; imides; active methylene compounds such as acetylacetone, acetoacetiv acid esters, ethyl malonate; mercaptanes; imines; ureas; diallyl compounds or sodium busulfite.

A curing agent or a crosslinking promoting agent may be incorporated together with the crosslinking agent.

The crosslinking agent may be incorporated into the aqueous dispersion in various ways in accordance with the kinds of the agents, for example, by admixing with the crystalline polyester resin (A) or the non-crystalline polyester resin (B), direct addition to the aqueous dispersion, or previously dissolving it in the water-soluble organic compound (C), or a mixture of the water-soluble organic compound (C) and water (D).

The aqueous polyester resin dispersion of the present invention has various utilities, such as adhesives, inks, particularly aqueous printing inks, coating compositions, aqueous binders for coating, or treating agents, for textile or paper products, particularly surface treating agents for drip-proofing and can provide these products with an excellent water resistance and excellent weatherability.

For example, the aqueous dispersion of the present invention can be used as a paint, particularly an easily peelable paint, which may be used for coating onto the surface of metals, steel plates, plastic articles or the like in order to prevent the products from soil or scratch during storage thereof and can easily be peeled off when the products are used. For this purpose, the aqueous dispersion may be used as it stands, or may be used after being admixed with other aqueous resin dispersions or emulsions, pigments or various other additives. Other aqueous resin dispersions or emulsions include aqueous dispersions or emulsions of acrylic resin, urethane resin, ethylene-vinyl acetate resin or rubber latex.

Pigments include inorganic pigments such as titanium oxide, silicone oxide, magnesium oxide, zinc oxide, talc; or other colouring agents. Other additives include fluoric, silicone or acrylic flowability improvers, antioxidants and antifungal agents.

The aqueous polyester resin dispersion of the present invention is useful for the preparation of various laminated products. Thus, the aqueous polyester resin dispersion may be coated onto the surface of various metallic products (e.g. various products of iron, aluminium, tin, lead or zinc more particularly cold-rolled steel plate, zinc phosphate-treated steel plate, galvanized sheet, tinplate, or aluminium plate, various plastic products (e.g. films or sheets of polyesters such as polyethylene terephthalate or polybutylene terephthalate, or polyvinyl chloride), or various fiber products (e.g. woven, knitted or non-woven products of synthetic fibers such as polyamide polyester or natural fibers such as cotton, wool), and thereon a non-solvent type polyester resin is coated or a polyester film is laminated, by which a laminated product having excellent durability, adhesion and water resistance is produced which is useful as an outdoor building material for pipes, fences, coated steel plates, or hot-melt adhesives.The aqueous polyester resin di dispersion can be coated onto the various products by conventional means such as a roller coater, bar coater, or spray coater in a thickness of 0.5 to 20y, preferably 1 to 10y. The coating of the non-solvent type polyester resin or the laminating of a polyester film onto the products coated with the aqueous dispersion can be carried out by conventional methods such as extrusion lamination, powder coating, film lamination, or the like in a thickness of 5 to 300, preferably 20 to 150,u.

The aqueous polyester resin dispersion of the present invention is also useful for the preparation of an aqueous printing ink mixing with pigments. Examples of suitable pigments are white pigments (e.g.

titanium oxide, zinc white, white lead), black pigments (e.g. carbon black, lamp black, graphite), gray pigments (e.g. zinc powder, lead suboxide, slate dust), red pigments (e.g. cadmium red, cadmiummercury red, red ocher), yellow pigments (e.g. cadmium yellow, zinc yellow, chrome yellow, titanium yellow), green pigments (e.g. viridian, chrome oxide green, cobalt green, chrome green), blue pigment pigments (e.g. ultramarine blue, iron blue, cobalt blue), violet pigments (e.g. manganese violet, cobalt violet), iron oxide pigments (e.g. mars yellow, iron oxide black), extender pigments (e.g. clacium carbonate, barium sulfate, alumina, talc, clay), azo type organic pigments (e.g. permanent red 4R, Hansa yellow G, Ha nsa yellow 1 OG, brilliant carmine 3B, brilliant carmine 6B), phthalocyanine organic pigments (e.g. phthalocyanine green, first sky blue), metallic powder pigments (e.g. silver pigments, copper pigment, gold pigment), glass powder, glass flake or glass bead. The pigments are incorporated in the weight ratio of 50-2:50-98 (pigments: polyester resin contained in the aqueous dispersion).

The aqueous printing ink may optionally contain conventional lubricating agents and defoaming agents, such as acrylic additives (e.g. Modaflow, made by Monsanto Co., or Polyflow S, made by Kyoeisha Yushi), silicone additives (e.g. Bysilone OL, made by Bayer, YF-38 18, XF-391 3, TSA-720, made by Toshiba Silicone). The aqueous printing ink thus obtained shows excellent adhesion to various plastic films (e.g. polyester film, polyvinyl chloride film), papers, metals (e.g. aluminium, copper, iron) and fiber woven products, and also shows excellent water resistance, anti-blocking properties and flexibility.

The aqueous polyester resin dispersion of the present invention is also useful as an aqueous binder for coatings when it contains amino resins as mentioned above. The aqueous binder for coatings may also contain curing agents (e.g. acids such as p-toluenesulfonic acid, dinonylnaphthalenedisulfonic acid, hydrochloric acid), modifying agents (e.g. acrylic resin dispersion, epoxy resin dispersion, urethane resin dispersion, aqueous polyisocyanate blocked with sodium hyposulfite etc.), organic or inorganiccinments or additives for paints (e.g. acrylic additives, silicone additives, fluorine additives).The aqueous binder for coatings has an excellent adhesion to metals and also an excellent water resistance, particularly resistance to boiling water, and excellent anticorrosion, and is useful for the coating of cans and further as a precoating, wire coating, or baking coating.

The aqueous polyester resin dispersion of the present invention is furthermore useful as a surface treating agent for drip-proofing various products such as plastic products (e.g. films, sheets or other articles of polyethylene terephthalate, polycarbonate or polyvinyl chloride), glass products or metallic products. The surface treating agents for the drip-proofing preferably contain a non-ionic surfactant, such as polyethylene glycol or its monocarboxylic acid ester, monoalkyl ether, monoalkylphenyl ether, sorbitan ester or polyethylenesorbitan ester, which preferably have an HLB of not less than 10, more preferably 13 to 30.The surface treating agent may also contain a water-soluble resin, for example, polyvinyl alcohol or a derivatives thereof such as saponified polyvinyl acetate, or a saponified product of a copolymer of vinyl monocarboxylate and a vinyl monomer (e.g. ethylene, propylene, styrene, vinyl chloride, acrylonitrile, acrylic acid, methacrylic acid, maleic acid, itaconic acid, or alkyl ester or hydroxyalkyl ester of these acids), wherein the saponification degree is preferably 40 to 100%, or an acetal product of a polyvinyl alcohol having an acetal degree of not more than 20%.The surface treating agent may further contain other conventional additives such as curing agents, curing promotors, weathering agents, lubricating agents, pigments, and further aqueous resins such as acrylic emulsion, acrylic dispersion, polyvinyl acetate emulsion, polyvinyl chloride emulsion, or self-emulsifiable polyurethane. The plastic products and glass products treated with the surface treating agent show excellent transparency, drip-proofing and durability and are suitable as materials for horticultural houses, windows or lens.

The present invention is illustrated by the following Preparations and Examples but is not limited thereto.

In the Preparations and Examples, "part" means part by weight unless specified otherwise, and various properties were measured in the following manner.

(1) Molecular weight: It was measured with a molecular weight measuring apparatus (115 type, made by Hitachi, Ltd).

(2) Softening point and melting point of crystals: They were measured with a wholly automatic melting point apparatus (Model FP-1 , made by Mettler Co).

(3) Particle size of the aqueous dispersion: It was measured with a grindometer and a light microscope.

(4) Viscosity: It was measured with a B type viscometer at 200 C.

(5) Adhesion: It was measured by the method as disclosed in ASTM D-3359.

(6) Tackiness of surface of the coating film: It was evaluated by finger touch.

(7) Solvent reistance: The coating film prepared from the aqueous dispersion was rubbed with a gauze inpregnated with xylene until the substrate appeared, and the time of rubbing was calculated.

(8) Erichsen value: It was measured by the method as disclosed in JIS Z-2247.

(9) Water resistance: It was measured by the method as disclosed in JIS 5400.

(10) Gloss: It was measured with a glossmeter (Type--VG 107, made by Nippon Denshoku Kogyo K.K.).

(11) Weatherability (degree of retention of surface gloss): After irradiating the coating film for 100 or 300 hours with Sunshine Weather-Ometer (made by Atlas), the gloss was measured.

The weatherability was also evaluated by measuring the change of appearance and adhesion after exposing the coating film outdoorforthree months.

(12) Anticorrosion: It was measured by the method as disclosed in JIS Z-237 1.

(13) Anti-blocking properties: It was evaluated by finger touch.

(14) Resistance against boiling water: After dipping the coating film in boiling water for one hour, the degree of retention of surface gloss was measured.

(1 5) Drip-proof: The inside wall of a stainless steel vessel was treated with a surface treating agent for giving drip-proof, and water was added to the vessel, which was heated at 500C, and then, there was observed the formation of moisture condensation on the treated wall.

Besides, the water resistance of the products treated with the surface treating agent for giving drip-proof was evaluated by measu ring the drip-proof, transparency and adhesion after washing the treated products with flowing water for onehour.

PREPARATION 1 Dimethyl terephthalate (95 parts), dimethyl isophthalate (95 parts), ethylene glycol (71 parts), neopentyl glycol (110 parts), zinc acetate (0.1 part) and antimony trioxide (0.1 part) were charged into a reactor and were subjected to an ester exchange reaction at 140 to 2200C for 3 hours. To the reaction mixture was added 5-sodium sulfo-isophthalic acid (6.0 parts), followed by subjecting the mixture to an esterification reaction at 220 to 2600C for one hour and further to a polycondensation reaction under recuced pressure (10--0.2 mmHg) at 240 to 2700C for 2 hours to give a polyester resin (B-i) having a molecular weight of 19,500 and a softening point of 1 600C.

In the same manner as described above except that the starting materials as shown in Table 1 were used, there were obtained various polyester resins (B--2 to B-8), properties of which are shown in Table 1.

TABLE 1

Polyester resin of the Polyester resin of present invention reference Components (% by mole*) and properties B-1 B-2 B-3 B-4 B-5 B-6 B-7 B-8 Terephthalic acid 49 30 47 30 50 - 80 68 Isophthalic acid 49 30 47 30 50 88 19 20 Poly- 5-Sodium sulfocarboxylic isophthalic acid 2 1.5 3 5 - 12 1 2 acid component Adipic acid - 38.5 - 30 - - - 10 Trimellitic acid anhydride - - 3 5 - - - Neopentyl glycol 60 45 58 45 60 - - 60 Polyol Ethylene glycol 40 55 42 55 40 - 100 40 component Diethylene glycol - - - - - 100 - Softening point ( C) 160 110 130 92 157 - 230** 68 Properties Molecular weight 19500 17000 3900 5200 18300 20100 21000 1550 *) % by mole in polyester (measured by NMR) **) Melting point of crystal PREPARATION 2 Dimethyl terephthalate (475 parts), dimethyl isophthalate (466 parts), dimethyl 5-sodium sufloiso-phthalate (45 parts), ethylene glycol (443 parts), neopentyl glycol (400 parts), zinc acetate (0.44 part), sodium acetate (0.05 part) and antimony trioxide (0.43 part) were charged in a reactor and were subjected to an ester exchange reaction at 140 to 2200C for 4 hours. The pressure of the reaction system was gradually reduced until 5 mmHg in one hour with raising the temperature until 2600C.

Finally, at2600C and under 0.1-0.3 mmHg, the mixture was subjected to a polycondensation reaction for one hour to give a non-crystalline polyester resin (B--9) having a molecular weight of 7,000 and a softening point of 1 520C. As a result of NMR analysis, the polyester resin (B--9) was composed of terephthalic acid: 49% by mole, isophthalic acid: 48% by mole, 5-sodium sulfoisophthalic acid: 3% by mole, ethylene glycol: 52% by mole, and neopentyl glycol: 48% by mole. Besides, the heat of fusion of the polyester resin (B--9) was measured with a differential scanning calorimeter, but no endothermic peak was observed.

In the same manner as described above except that the starting materials as shown in Table 2 were used, there were obtained various crystalline polyester resins (A-1 to A-4) and various noncrystalline polyester resins (B-1 0 to B-1 3), properties of which are shown in Table 2.

TABLE 2

Pc ly aster resins of the Polyesters resins present invention of reference Components (% by mole) and properties A-1 A-2 A-3 B-9 B-10 B-11 B-12 B-13 Dicarboxylic acid component:: Terephthalic acid 50 57 65 49 45 - 32 50 Isophthalic acid 10 40 - 48 50 80 30 50 5-Sodium sulfo isophthalic acid 2 3 7 3 4 20 3' Adipic acid 38 - 28 - - - 35 Trimellitic acid anhydride - - - - 1 - - Glycol component:: Ethylene glycol 35 - 25 52 58 - 50 53 Neopentyl glycol | - | - | - | 48 | - | - | 50 | 47 1,4-Butanediol 65 52 70 - | - | - | - | - 1,6-Hexanediol - 45 - - 42 - - - Diethylene glycol | - | - | - | - | - | 100 | - | - | Polytetramethy lene glycol (MW=1000= 3 5 - - - - - Properties: Softening point (C) -. - - 152 130 105 < 30 148 Melting point( C) | 116 | 128 | 110 | - | - | - | - | Heat of fusion 270 320 260 0 0 0 0 0 (cat/unit) Molecular weight 18000 16000 15000 7000 12000 15000 1500 12000 PREPARATION 3 In the same manner as described in Preparation 2 except that the starting materials as shown in Table 3 were used, there were obtained polyester resins (B-15 to B-18), properties of which are shown in Table 3.

TABLE 3

Polyester resin of Polyester resin the present invention of reference Components (% by mole) and properties B-15 B-16 B-17 B-18 Polycarboxylic acid component: Terephthalic acid 43 50 48 30 lsophthalicacid 50 50 48 15 Sebacic acid - - 50 SSodium Sulfo isophthalic acid 7 - 4 5 Glycol component:: Ethylene glycol - 45 50 50 144-Butanediol 35 - - Neopentyl glycol - 55 50 50 Po lytetramethy lene glycol (MW=1000) - - 1,6-Hexanediol - - DA - 350* 65 - Properties: Molecular weight 18000 16000 2000 25000 Softening point ( C) 175 160 68 Lower than toom temp.

Melting point( C) *) DA350: An adduct of ethylene oxide (2.5 mole) to bisphenol A (1 mole) (made by Nihon Yushi) PREPARATION 4 Dimethyl terephthalate (970 parts), ethylene glycol (546 parts), neopentyl glycol (229 parts), zinc acetate (0.44 part) and antimony trioxide (0.43 part) were charged into a reactor and were subjected to an ester exchange reaction at 1 40 to 2200C for 3 hours. The pressure of the reactor was reduced until 5 mmHg at 220 to 2600C in 30 minutes, and thereafter the mixture was subjected to a polycondensation reaction at 265 C and under 0.1 to o,3 mmHg for 90 minutes to give a faint yellow, transparent polyester resin (P-1) having a molecular weight of 20,000 and softening point of 175 C. As a result of NMR analysis, the polyester resin (P-1) was composed of terephthalic acid: 100% by mole, ethylene glycol: 68% by mole and neopentyl glycol: 32% by mole.

In the same manner as described above except that the starting materials as shown in Table 4 were used, there were obtained polyester resins (P-2 and P-3), properties of which are shown in Table 4.

TABLE 4

Non-solvent type polyester resin Components (% by mole) and properties P-l P-2 P-3 Polycarboxylic acid component: Terephthalic acid 100 85 95 Isophthalic acid | - | 15 Adipicacid acid Trimellitic acid anhydride ~ ~ 5 Glycol component:: Ethylene glycol 68 100 65 1,4-Butandediol - Neopentyl glycol 32 - 35 Polytetramethylene glycol - - Properties: Melting point (-C) - 216 Softening point ( C) | 175 | - | 82 Molecular weight 20000 18000 2800 PREPARATION 5 Dimethyl terephthalate (95 parts), dimethyl isophthalate (95 parts), ethylene glycol (71 parts) neopentyl glycol (110 parts), zinc acetate (0.1 part) and antimony trioxide (0.1 part) were charged into a reactor and were subjected to an ester exchange reaction at 140 to 2200C for 3 hours.After adding thereto 5-sodium sulfo-isophthalic acid (6.0 parts), the mixture was subjected to an esterification reaction at 220 to 2600C for one hour and further subjected to a polycondensation reaction at 240 to 2700C under reduced pressure (10 to 0.2 mmHg) for 2 hours to give a polyester resin (B-1 9) having a molecular weight of 19,500 and a softening point of 1 600C.

In the same manner as described above except that the starting materials as shown in Table 5 were used, there were obtained polyester resins (B-20 to B-23), properties of which are shown in Table 5.

TABLE 5

Polyester resins of Polyesters resins the present invention of reference Components (% by mole) and properties | B-19 | B-20 | B-21 | B-22 | B-23 Polycarboxyl ic acid component:: Terephthalic acid 49 49 43 50 Isophthalic acid 49 48 20 50 88 5-Sodium sulfo isophthalic acid 2 3 2 - 12 Adipic acid | - | - | 30 | - | Trimellitic acid anhydride - 5 Glycol component:: Ethylene glycol 40 48 - 40 Neopentyl glycol 60 - 45 60 DA - 350 - 52 - - Cyclohexanedimethanol - - 55 - Diethylene glycol - - - - 100 Properties:: Softening point ( C) 160 178 74 157 Molecular weight 19500 16000 3100 18300 20100 PREPARATION 6 In the same manner as described in Preparation 1 except that the starting materials as shown in Table 6 were used, there were obtained polyester resins (B 24 to B-28), properties of which are shown in Table 6.

TABLE 6

Polyester resins of the Polyester resins of present invention reference Components (% by mole) and properties B-24 B-25 826 827 828 Acid component: Terephthalic acid 40 45 50 48 40 Isophthalic acid 40 45 50 40 30 5-Sodium sulfo isophthalic acid 5 10 - 12 30 Adipic acid 15 - - - Glycol component:: Ethylene glycol 40 30 53 | - | 51 Neopentyl glycol | 20 | - | 47 | - | 49 1,6-Hexanediol - 40 - - DA - 350 40 30 - | - | - Diethylene glycol | - | - | - 100 | Properties:: Molecular weight 15000 16000 15000 15000 12000 Melting point ( C) 145 138 154 132 151 PREPARATION 7 In the same manner as described in Preparation 1 except that the starting materials as shown in Table 7 were used, there were obtained polyesters resins (B-29 to B-36), properties of which are shown in Table 7.

TABLE 7

Polyester resins of the present invention Poylester resins of reference Starting materials (% by mole) and properties B-29 B-30 B-31 B-32 B-33 B-34 B-35 B-36 Acid component: Terephthalic acid 54 35 48 49 - 50 43 15 Isophthalic acid 43 31 48 48 90 50 42 12 Adipic acid - 30 - - - - - 70 Trimellitic acid - - 2 1 - - - 5-Sodium sulfo Isophthalic acid 3 4 2 2 10 - 15 3 Glycol component: : Ethylene glycol 45 - - 38 - 46 45 50 Neopentyl glycol 55 42 - - - 54 55 50 1,6-Hexanediol - - 56 62 - - - 1,4-Cyclohexandimethanol - 58 - - - - - DA - 350 - - 44 - - - - Diethylene glycol - - - - 100 - - Properties:: Molecular weight 15000 12000 5500 7000 16000 15000 12000 15000 Softening point ( C) 157 110 135 132 106 156 161 65 PREPARATION 8 In the same manner as described in Preparation 1 except that the starting materials as shown in Table 8 were used, there were obtained polyester resins (B-37 to B=42), properties of which are shown in Table 8.

TABLE 8

Polyester resins of Polyester resins of the present invention reference Component (% by mole) and properties B-37 B38 B-39 B-40 | B-41 B-42 Dicarboxylic acid component: Terephthalic acid 54 58 35 55 40 42 Isophthalic acid 43 37 32 45 38 37 Sodium sulfo isophthalic acid 3 5 3 - 22 21 Adipic acid 30 Glycol component:: Ethylene glycol 45 60 50 46 - 55 Neopentyl glycol 55 39.5 - 54 - 45 1,4-Cyclohexane dimethanol | - | - | - | - | - | Polyethylene-glycol (MW=4000) - 0.5 - - - Diethylene glycol - - - - 100 DA - 350 - - 50 - - Properties:: Molecular weight 15003 17000 14000 14000 7500 6700 Softening point (-C) 157 156 175 153 102 135 EXAMPLE 1 Polyester resin (B-1) (300 parts) and n-butyl cellosolve (140 parts) were charged into a vessel and were agitated at 150 to 1 700C for about 3 hours to give a homogeneous, viscous mixture.To the mixture was gradually added with vigorous agitation water (560 parts) over a period of about one hour to give a faint bluish white aqueous dispersion (X-1). The aqueous dispersion had a particle size of less than 1y. When this aqueous dispersion was allowed to stand at -50C for 20 days, no change of appearance and viscosity was observed, and the aqueous dispersion showed excellent storage stability.

The aqueous dispersion (X-i) was coated onto a polyethylene terephthalate film (thickness: 125y) with a bar coater &num;20 in a thickness of 1 0,u (in dry state) and then dried at 1 000C for 20 minutes. The resulting coating layer had very excellent adhesion, and even when it was dipped in water, it showed excellent water resistance without showing any blushing.

EXAMPLES 2 TO 5 In the same manner as described in Example 1 except that the starting materials as shown in Table 9 were used, there were prepared some aqueous dispersions (X-2 to X-5), properties of which are shown in Table 10.

The aqueous dispersions (X-2 and X-5) were coated onto a polyethylene terephthalate film (thickness: 1 25,u) in the same manner as in Example 1. The properties of the resulting coating layers as well as those of Example 1 are shown in Table 11.

REFERENCE EXAMPLES 1 TO 5 In the same manner as described in Example 1 except that the starting materials as shown in Table 9 were used, there were prepared some aqueous dispersions (X-6 to X-10), properties of which are shown in Table 10.

The aqueous dispersions (x-7 to X-9) were coated onto a polyethylene terephthalate film (thickness: 125 ) in the same manner as described in Example 1. The properties of the resulting coating layers are also shown in Table 11.

TABLE 9

Example No. Reference Example No.

Aqueous dispersion X-1 X-2 X-3 X-4 X-5 X-6 X-7 X-8 X-9 X-10 Polyester resin (B-1) (B-2) (B-3) (B-4) (B-2) (B-5) (B-6) (B-7) (B-1) (B-8) 300 300 400 400 200 300 300 300 100 200 n-Butyl cellosolve 140 140 80 90 60 140 - 140 - Ethyl cellosolve - - - 50 40 - - - - Ethanol - - 20 - - - - - Surfactant* - - - - - - - - - 4 Water 580 560 500 580 700 560 700 560 900 700 *) Surfactant: Noniolite AL-20 (made by Kyoeisha Yushi).

TABLE 10

Example No. Reference Example No.

Properties of aqueous dispersions 1 2 3 4 5 1 2 3 4 5 Aqueous dispersion X-1 X-2 X-3 X-4 X-5 X-6 X-7 X-8 X-9 X-10 State of Dispersi- dispersion* o o o o o x o # # o bility Particle size( ) < 1 < 1 < 1 < 1 < 1 - < 10 < 2000 < 2000 < 1 Change of No No No No No Frozen Frozne appearance change change change change change - Frozen Separated separated separated Cahnge of Aqueous Storage particle dispersion stability size* " " " " " - could - - (-5 C, not be 20 days) Change of recovered viscosity (cps)** < 100 < 100 < 100 < 100 < 100 - - - *) o: Excellent dispersibility (faint bluish white aqueous dispersion), #: Inferior dispersibility (white turbid dispersion was obtained, but it had wide range of particle distribution), x: Entirely not dispersed (separated) **) The were evaluated after being allowed to stand at 25 C for 24 hours.

TABLE 11

Example No. Reference Example No.

Properties of coating layer 1 2 5 2 3 4 Aqueous dispersion X-1 X-2 X-5 X-7 X-8 X-9 Appearance Excellent Excellent Excellent Excellent Bad* dis- Bad, continuous uneven layer thickness Adhesion 100/100 100/100 100/100 100/100 94/100 After Adhesion 100/100 100/100 100/100 45/100 Impossible dipping Blushing to 93/100 Water (25 C Appear- No No No measure No resis- 3 days) ance change change change change tance** After Adhesion 100/100 100/100 100/100 93/100 dipping Dissolved (60 C, Appear- No No No out No 2 hours) ance change change change change *)When it was cooled and dried, it crtystallized and no continuous layer was formed.

**) It was evaluated after being dipped in water, followed by wiping up water.

EXAMPLES 6 TO 8 To the aqueous dispersion (X-1 , X-3 or X-5) (each 1 00 parts) were added a melamine resin (Sumimal M-50, made by Sumitomo Chemical Co.) (10 parts) and a 50% by weight solution (0.5 part) of a silicone compound (XF-391 3, made by Toshiba Silicone Co.) in ethanol, and the mixture was agitated well to give a homogeneous vanish. The resulting varnish was coated onto a polyethylene terephthalate film (thickness 1 00y) with a bar coater &num;26 in thickness of 10 (in dry state) and baked at 1 000C for 30 minutes to give a hardened coating layer, properties of which are shown in Table 12.

REFERENCE EXAMPLES 6 AND 7 In the same manner as described in the above Examples 6 to 8 except that the aqueous dispersions (X-7 and X-1 0) were used, hardened coating layers were formed on a polyethylene terephthalate film (thickness: 125 ). The properties thereof are also shown in Table 1 2.

TABLE 12

Water resistance Tackiness Solvent (25eC, 3 days) Example of resistance No. Adhesion surface (times) Adhesion Appearance Ex. 6 100/100 No > 50 100/100 No change .. 7 100/100 No > 50 100/100 " 8 100/100 No > 50 100/100 Ref.

Ex. 6 100/100 Yes 35 60/100 Blushing 7 7 100/100 No > 50 40/100 Blushing EXAMPLES 9 AND 10 To the aqueous dispersion (X-1 or X-3) (each 100 parts) were added a melamine resin (Suminal M-50, made by Sumitomo Chemical) (10 parts), a 50% by weight solution (0.5 part) of a silicone compound (XF-391 3, made by Toshiba Silicone) in ethanol and titanium oxide (10 parts), and the mixture was mixed with agitation and then kneaded with a three-roll mill to give a white composition.The resulting composition was coated onto a soft steel panel with a bar coater &num;26 in a thickness of 1 0 (in dry state) and baked at 1 500C for 10 minutes. The properties of the resulting coating layer are shown in Table 1 3.

REFERENCE EXAMPLES 8 AND 9 In the same manner as described in Examples 9 and 10 except that the aqueous dispersions (X-7 and X-1 0) were instead of aqueous dispersion (X-1 ), there was formed a coating layer, properties of which are also shown in Table 13.

TABLE 13

Example No. Reference Example No.

Properties 9 10 8 9 Erichsen value (mm) > 7 > 7 > 7 6 Adhesion 100/100 103/100 100/100 100/100 Weatherability (degree 72 78 18 46 of retention of gloss, %) (chalking) Degree of Water retention of 97 98 45 40 resistance gloss (%) (S0C.

150 hrs.) Adhesion 100/100 100/100 55/100 34/100 EXAMPLE 11 In the same manner as described in Preparation 1, there was produced a polyester resin (B-43) which was composed of terephthalic acid: 67% by mole, isophthalic acid: 20% by mole, 5-sodium sulfoisophthalic acid: 3% by mole, ethylene glycol: 40% by mole and neopentyl glycol: 60% by mole, and had a softening point of 135 C and a molecular weight of 1 6,000.

In the same manner as described in Example 1 except that the polyester resin (B-43) was used instead of the polyester resin (B-i), there was prepared and aqueous dispersion (X-1 1), and the aqueous dispersion (X-1 1) was coated onto a polyethylene terephthalate film (thickness: 125 ) to form a coating layer. The properties of the aqueous dispersion and coating layer are shown in Table 1 4.

TABLE 14

Properties of aqueous dispersion and coating layer Example 11 Aqueous dispersion | X-11 Properties Disper- State of dispersion* o of aqueous sibility dispersion Particle size ( ) Storage Change of appearance No change stability (5- C. Change of particle size 20 days) Change of viscosity (cps) < 100 Appearance Excel lent Properties Adhesion 100/100 of coating layer Water After Adhesion 100/100 resis- dipping tance (25 C, 3 days) Appearance No change After Adhesion 100/ 100 dipping (60 C, Appearance No change 2 hrs.) *) o: Excellent dispersibility (faint bluish white aqueous dispersion).

EXAMPLE 12 In the same manner as described in Example 7 except that the aqueous dispersion (X-1 1) was used instead of the aqueous dispersion (X-1), there were prepared a coating composition and a coating layer. The properties of the coating layer are shown in Table 1 5.

TABLE 15

Properties of coating layer Example 12 Erichsen value (mm) > 7 Adhesion 100/100 Weatherability (degree of retention of glo3s, %) 70 Water Degree of retention resistance of gloss (%) 95 (50 C, 150 hrs) Adhesion 100/100 EXAMPLE 13 The cyrstalline polyester resin (A-i) (120 parts), the non-crystalline polyester (B--9) (180 parts) and n-butyl cellosolve (140 parts) were charged into a vessel and the mixture was agitated at 1 50 to 1 700C for about 3 hours to give a homogeneous viscous mixture.To the mixture was gradually added with vigorous agitation water (560 parts) over a period of about one hour to give a faint bluish white aqueous dispersion (X-1 2). The aqueous dispersion had a particle size of less than 1 y. When this aqueous dispersion was allowed to stand at-50C for one month, no change of appearance was observed, and the aqueous dispersion showed excellent storage stability.

The aqueous dispersion (X-1 2) was coated onto a polyethylene terephthalate film (thickness: 125,u) with a bar coater &num;20 in thickness of 1 0ju (in dry state and then dried at 1 000C for 20 minutes.

The resulting coating layer had very excellent adhesion, and even when it was dipped in water for 7 days, and further even when it was dipped in a hot water of 600C for one day, it showed excellent water resistance without showing any blushing.

EXAMPLES 14 TO 16 AND REFERENCE EXAMPLES 10 TO 16 In the same manner as described in Example 13 except that the starting materials as shown in Table 1 6 were used, there were prepared aqueous dispersions (X-1 3 to X-22), and further coating layers therefrom. The properties of the aqueous dispersions and coating layers are shown in Table 1 7 and Table 1 8, respectively.

TABLE 16

Example No. Reference Example No.

Starting materials (part) 14 15 16 10 11 12 13 14 15 16 Aqueous dispersion X-13 X-14 X-15 X-16 X-17 X-18 X-19 X-20 X-21 X-22 Cyrstalline polyester A-1 A-2 A-3 A-1 A-1 A-1 A-1 A-1 A-1 A-1 resin 60 180 150 120 120 300 80 80 150 150 Non-crystalline poly- B-10 B-10 -9 B-11 B-12 - B-9 B-9 B-13 B-9 ester resin 140 120 150 180 180 120 120 150 150 n-Butyl cellosolve - - 140 140 140 140 - - 140 Ethyl cellosolve - 100 - - - - - - - Dioxane 80 40 - - - - - - - Isopropanol 80 - - - - - - - - Surfactant* - - - - - - - 4 - Water 640 560 560 560 560 560 560 800 560 700 *)Nonionite AL-20, made by Kyoeischa Yushi kagaku Kogyo K.K.

TABLE 17

Example No. Reference Example No.

Properties of aqueous dispersion 14 15 16 10 11 12 13 14 15 16 Aqueous dispersion X-13 X-14 X-15 X-16 X-17 X-18 X-19 X-20 X-21 X-22 Disper- State of sibility dispersion* o o o o o x x o x x Particle size( ) < 1 < 1 < 1 < 1 < 1 > 100 > 100 < 1 > 100 > 100 Storage Change of No No No No No Frozen stability appearance change change change change change Separated Separated separated Separated Separated (-5 C, 1 month) Change of particle** " " " " " - - - - *) o: Excellent dispersibility (faint bluish white aqueous dispersion), #: Inferior dispersibility (white turbid dispersion was obtained, but it had wide range of particle distribution), x: Entirely not dispersed (separated) **) The were evaluated after being allowed to stand at 25 C for 24 hours.

TABLE 18

Example No. Reference Example No.

Properties of coating layer 14 15 16 10 11 12 13 14 15 16 Aqueous dispersion X-13 X-14 X-15 X-16 X-17 X-18 X-19 X-20 X-21 X-22 Appearance Excellent Excellent Excellent Excellent Excellent Bad Bad Bad Bad Bad Adhesion 100/100 100/100 100/100 100/100 100/100 92/100 Water After Adhesion 100/100 100/100 100/100 75/100 80/100 Impos- Impos- 90/100 Impos- Imposresis- dipping sible sible sible sible tance (25 C, Appear- No No No Blushing Blushing to to No to to 7 days) ance change change change measure measure change measure measure Adhesion 100/100 100/100 100/100 0/100 25/100 86/100 After dipping Appear- No No No Blushing Blushing Slightly (60 C, ance change change change blushing 1 day) EXAMPLE 17 The crystalline polyester resin (A-i) (150 parts), the non-crystalline polyester resin (B--9) (150 parts), and n-butyl cellosolve (140 parts) were charged into a vessel and were agitated at 150 to 1 700C for about 3 hours to give a homogeneous viscous mixture. To the mixture was gradually added with vigorous agitation water (560 parts) over a period of about one hour to give a homogeneous, faint bluish white aqueous dispersion. To this aqueous dispersion was added a methylated melamine resin (Sumimal M--50 W, made by Sumitomo Chemical Co.) (45 parts), and the mixture was agitated to give a homogeneous aqueous dispersion (X 23). This aqueous dispersion had a particle size of less than 1 y, and when it was allowed to stand at -50C for one month, no change of appearance was observed, and the aqueous dispersion showed excellent storage stability.

The aqueous dispersion (X-23) was coated onto a polyethylene terephthalate film (thickness: 1 25y) with a bar coater in a thickness of 10,*4 (in dry state) and the coating layer was hardened at 1 000C for 30 minutes and then dried. The coating layer thus formed had an excellent adhesion as 100/100, and excellent water resistance. That is, even when it was dipped in water for 7 days and further even when it was dipped in hot water of 600C for one day, it did not show any blushing.

EXAMPLES 1 8 TO 21 AND REFERENCE EXAMPLES 17TO21 The aqueous dispersions prepared in Example 13 to 1 5 and 17 and Reference Examples 10 to 14 were each coated onto a suede cloth of 100% polyester with a bar coater &num;20 and then dried at room temperature for 24 hours. The coated cloths were piled up by facing each coated surface and bonded at 1 500 C, under pressure of 300 g/cm2 for 10 minutes. The adhesion (peal strength) of the bonded cloths was measured with an Instrone type peel strength tester (made by Shimazu Seisakusho). Besides, the bonded cloths were dipped in hot water of 600C for one day, and the adhesion (peal strength) was also measured, and the retention thereof was calculated. The results are shown in Table 1 9.

TABLE 19

Example No. Reference No.

Properties 18 19 20 21 17 18 19 20 21 Aqueous dispersion X-12 X-13 X-14 X-23 X-16 X-17 X-18 X-19 X-20 Initial Adhesion (kg/cm) 1.2 0.87 0.94 1.6 1.1 0.22 Impos- Impos- 0.88 sible to sible to Adhesion (kg/cm) coat coat after dipping 1.0 0.74 0.80 1.4 0.64 0.08 0.47 at 60 C for 1 day Retention (%) 83 85 85 88 58 36 53 EXAMPLE 22 The polyester resin (B-i 5) (300 parts) was mixed intb n-butyl cellosolve (70 parts), and the mixture was added with vigorous agitation into a mixture of isopropanol (70 parts) and water (506 parts), and the mixture was agitated for about one hour to give a homogeneous faint bluish white aqueous dispersion (X-24).

The aqueous dispersion (X-24) was coated into a steel panel coated with a melamine alkid resin (Amilac red, made by Kansai Paint Co.) with a cup gun in a thickness of 30 y and dried at 1 000C for 10 minutes.

When this product was subjected to a peel strength test at 1 800, it showed a peel strength of 60 g/cm and could easily be peeled off with hand. When this test piece was dipped in hot water of 400C for 300 hours, the peelable paint composition did not show any dissolution, swelling, cracking and peeling, and when it was subjected to peel strength test, it showed a peel strength of 50 g/cm and could easily be peeled off with hand. Moreover, after this samples was irradiated with a sunshine weatherometer for 100 hours and further exposed outdoor for 3 months, it was tested likewise. As the result, there was observed no deterioration such as softening or cracking, and the peel strength in each test were 36 g/cm and 50 g/cm, respectively.

Besides, the melamine alkid paint which was coated to the steel panel had an initial gloss of 94, and the gloss thereof was still 94 even after subjected to tests for water resistance and weatherability, which means that the peelable paint composition of this example does not show any bad effect on the coating layer of the melamine alkid paint but rather shows protective effect. When the peelable paint composition was not coated, the melamine alked paint-coated steel panel showed a gloss of 94 after being subjected to water resistance, a gloss of 92 after irradiation with a sunshine weather-ometer, and a gloss of 92 after being exposed outdoor.

In the same manner as described above, various aqueous dispersions were prepared by using polyester resins as shown in Table 20, and the aqueous dispersions were tested. The results are shown in Table 21.

TABLE 20

Example Reference Example No.

Aqueous dispersion and dispersibility thereof 22 22 23 24 Aqueous dispersion X-24 X-25 X-26 - Polyester resin B15 B-16 B-17 B-iS (part) 300 300 150- 300 B-18 150 n-Butyl cellosolve (part) 70 70 70 Isopropanol (part) 70 70 70 Methyl ethyl ketone (part) - - - 700 Water (part) 560 560 560 Dispersibi lity Excel lent Bad i Excel lent Excel lent TABLE 21

Example Reference Example No.

Properties of peel able paint composition 22 22 23 24 Aqueous dispersion X-24 X-25 X-26 Initial gloss (OJo) of melamine alkid paint 94 94 94 Initial peel strength Hardly Hardly (g/cm) 60 coated peeled 130* Change of No No Water appearance change Cracking change resis tance Peel strength Hardly tance 50 peeled 105 Change of No appearance change Cracking change Peel strength Hardly Sunshine (g/cm) 36 peeled 90 weather- Gloss of coating ometer layer (%) 92 - 82 Change of No No appearance change Cracking change Exposed .

outdoor Peel strength Hardly (g/cm) 50 peeled 95 Gloss of coating layer (%) 92 - 84 *) It was difficult to completely peel the coating layer, since a part of the coating layer was broken by peeling thereof.

EXAMPLE 23 The polyester resin (B-1 9) (300 parts) and n-butyl cellosolve (140 parts) were charged into a vessel and agitated at 1 50 to 1 700C for about 3 hours to give a homogeneous viscous mixture. To the mixture was gradually added with vigorous agitation water (560 parts) over a period of about one hour to give a faint bluish white aqueous dispersion (X-27).

To the aqueous dispersion (X-27) was added a water-soluble melamine resin (Sumimal M-50W, made by Sumitomo Chemical Co.) (35 parts), and the mixture was mixed well to give a homogeneous aqueous dispersion. This dispersion was coated onto a cold-rolled steel panel (thickness; 0.8 mm) treated with zinc phosphate with a roll coater in a thickness of 10,u, dried at 1 000C for 5 minutes and then cured at 2400C for one minute. Onto this layer thus formed was coated the polyester resin (P-1) at 2400C with an extruder in a thickness of 50 y to give a coated steel panel. Properties of this coated steel panel were tested. As a result, it showed excellent mechanical strength, water resistance and anticorrosion, as shown in Table 22.

EXAMPLE 24 In the same manner as described in Example 23, the polyester resin (B--20) (300 parts) was dissolved in n-butyl cellosolve (80 parts) and cyclohexanone (60 parts), and thereto was gradually added water (560 parts) to give an aqueous dispersion (X-28).

To the aqueous dispersion (X-28) were added a water-soluble melamine resin (Sumimal M-50W) (45 parts) and a homogeneous dispersion (100 parts) of titanium oxide (50% by weight as solid component) in ethylene glycol. The resulting homogeneous mixture was coated onto a cold-rolled steel panel (thickness: 0.8 mm) treated with zinc phosphate in a thickness of 10 Ei, dried at 1 000C for 5 minutes and then cured at 2400C for one minute.

Onto the coating layer thus formed was coated polyester resin (P-1) which was previously mixed with 20% by weight of titanium oxide with an extruder at 2200C in a thickness of 70 y to give a coated steel panel. Properties of this coated steel panel were tested. As a result, it showed excellent mechanical strength, water resistence and anticorrosion, as shown in Table 22.

EXAMPLE 25 In the same manner as described in Example 23, the polyester resin (B--21) (300 parts) was dissolved in n-butyl cellosolve (70 parts) and butyl acetate (30 parts and thereto was gradually added water (600 parts) to give an aqueous dispersion (X-29).

To the aqueous dispersion (X-29) was added a water-soluble melamine resin (Sumimal M-50W) (40 parts). The resulting homogeneous mixture was coated onto a cold-rolled steel panel (thickness: 0.8 mm) with a bar coater in a thickness of 6 u, dried at 1 000C for 5 minutes and then cured at 2400C for one minute.

Onto the coating layer thus formed was coated a powder coating composition which was prepared by mixing the polyester resin (P-3) (1000 parts), a crosslinking agent (U--l, made by Bayer) (220 parts), titanium oxide (400 parts), polyflow (made by Kyoeisha Yushi Kagaku Kogyo) (5 parts) and dibutyl tin dilaurate (3 parts) and pulverizing the mixture. The coating was carried out with an electrostatic coating machine in a thickness of 50,u and then the coating layer was cured at 1 800C for 20 minutes to give a coated steel panel. Properties of this coated steel panel were tested. As a result, it showed excellent mechanical strength, water resistance and anticorrosion, as shown in Table 22.

REFERENCE EXAMPLE 25 Without coating any aqueous dispersion, the polyester resin (P-2) was coated onto a cold-rolled steel panel (thickness: 0.8 mm) treated with zinc phosphate with an extruder at 2400C in a thickness of 50 iu to give a coated steel panel. Properties of this coated steel panel were tested. As a result, it did not show sufficient adhesion and it was inferior in the anticorrosion, too.

REFERENCE EXAMPLE 26 In the same manner as described in Example 23, the polyester resin (B--22) (300 parts) was dissolved in n-butyl cellosolve (140 parts), and thereto was gradually added water (560 parts).

However, the polyester resin coagulated and there could not be obtained any stable aqueous dispersion, and the mixture could not be coated onto a steel panel.

REFERENCE EXAMPLE 27 In the same manner as described in Example 23, the polyester resin (B23) (300 parts) was dissolved in hot water of 70 to 900C (700 parts), and the mixture was agitated for about 3 hours to give a homogeneous aqueous dispersion (X-30).

To the aqueous dispersion (X-30) was added a water-soluble melamine resin (Sumimal M-50 W) (35 parts), and the resulting homogeneous mixture was coated onto a cold-rolled steel panel (thickness; 0.8 mm) treated with zinc phosphate with a roll coater in a thickness of 10,u, dried at 1 000C for 5 minutes, and then cured at 2400C for one minute.

Onto the coating layer thus formed was coated the polyester resin (P-2) with an extruder at 2400C in a thickness of 50 L to give a coated steel panel. Properties of this coated steel panel were tested. As a result, it showed insufficient water resistance and anticorrosion, as shown in Table 22.

TABLE 22

Example No. Reference Example No.

Properties of coating layer 23 24 25 25 26 27 Appearance Excellent Excellent Excellent Good Excellent Adhesion 100/100 100/100 100/ 100 0/100 Impos- 100/100 sible Erichsen value to (mm) 7 < 7 < 7 < 7 < coat 7 < Water resistance* 100/100 100/100 100/100 0/100 0/100 Anti corrosion ** (mm) 1 > 1 > 1 > 4.5 3.2 *) It was evaluated after being kept at 500C for 300 hours.

**) It was evaluated in account of the width corroded after being dipped in water at 40"C for 500 hours.

EXAMPLES 26 AND 27 AND REFERENCE EXAMPLES 28 TO 30 The polyester resins (B-24to B-28) were each added to a mixture of water and isopropanol (and n-butyl cellosolve or tert-butyl cellosolve in Examples 26 and 27) in an amount as shown in Table 23, and the mixture was mixed at 70 to 750C for 3 hours to give aqueous binders for printing ink, which had a particle size of less than 1,u. After these binders were kept at OOC for one month, the state of dispersion was observed. The results are shown in Table 23.

The binders (aqueous dispersion) thus formed (100 parts), titanium oxide (15 parts) and a 50% by weight solution (0.5 part) of a silicone compound (XF-39 13, made by Toshiba Silicone Co.) were mixed with a ball mill to give a white aqueous ink. This ink was coated onto a polyethylene terephthalate film (thickness: 125,u) with a bar coater &num;20 in the thickness of 7 u and dried at 700C for 2 minutes. The properties of the coating layer were measured. The results are shown in Table 23.

TABLE 23

Example No. Reference Example No.

Components (% by weight) 26 27 28 29 30 Polyester resin B-24 35 - - - - B-25 - 35 - - B-26 - - 30 - - B-27 - - - 30 B-28 - - - - 30 Isopropanol 10 8 14 14 14 n-Buty I cellosolve 3 - - - - tert-Buty I cellosolve - 4 - | - | - Water 52 53 56 56 56 Dispersibility Excellent Excellent Bad Excellent Excellent Gloss 86 85 - 82 78 Anti-blocking Excellent Excellent Bad Bad Adhesion 100/100 100/100 - 100/100 25/100 Water No No - Losing Losing resistance* change change gloss gloss *) After being dipped in water at 30"C for one day, the appearance was observed.

EXAMPLE 28 The polyester resin (B-29) (300 parts) and n-butyl cellosolve (140 parts) were charged into a vessel and were agitated at 150 to 1 700C for about 3 hours to give a viscous mixture. To the mixture was gradually added with vigorous agitation water (560 parts) over a period of about one hour to give a homogeneous, faint bluish white aqueous dispersion.To this aqueous dispersion (100 parts) was added an amino resin (Sumimal M-50W, made by Sumitomo Chemical Co., in the form of a 80% by weight aqueous solution) (20 parts) to give an aqueous binder for coating which contained the polyester resin (B--29): 25% by weight, the amino resin: 13 S by weight a watercompartible organic compound: 12% by weight, and water: 50% by weight.

The aqueous binder was allowed to stand at 0 C and 40 C for one month, but any change of appearance was not observed.

To the aqueous binder (100 parts) were added a homogeneous dispersion of titanium oxide in ethylene glycol (solid content: 50% by weight) (40 parts) and a 50% by weight solution (0.5 part) of a painting additive (XF-39 1 3, made by Toshiba Silicone Co.) in ethanol, and the mixture was mixed well to give an aqueous coating composition.

The aqueous coating composition was coated onto a cold-rolled steel panel treated with zinc phosphate with a bar coater &num;36 in a thickness of 20 M dried at 1 500C for 2 minutes and baked at 2500C for 2 minutes. The coating layer thus formed had excellent gloss and smootheness and further had a pencil hardness: 2H, Erichsen value: more than 7 mm, and adhesion: 100/100, an adhesion after testing the water resistance for 300 hours: 100/100, a width corroded after testing anticorrosion for 300 hours: 2.5 mm, and a degree of retention of gloss after testing boiling water resistance: 95%.

EXAMPLES 29 TO 31 AND REFERENCE EXAMPLES 31 TO 33 In the same manner as described in Example 28, various aqueous binders were prepared by using the starting materials as shown in Table 24. Properties of the aqueous binders are shown in Table 24.

By using these aqueous binders there were prepared aqueous coating compositions which were coated onto a cold-rolled steel panel likewise to form coating layers. Properties of the coating layers are shown in Table 25.

TABLE 24

Exampel No. Reference Example No.

Components (% by weight) 28 29 30 31 31 32 33 B-29 B-30 B-31 B-32 B-33 B-34 B-35 Polyester resin 25 30 40 35 25 25 25 Amino resin 13 15 10 12 13 13 13 Organic compounds compatible with water:: n-Butyl cellosolve 12 4 5 6 12 12 12 t-Butyl cellosolve - 4 - - - - Cyclohexanone - - 5 - - - Isopropanol - - - 4 - - Water 50 47 40 43 50 50 50 State of Dispersion in water Excellent Excellent Excellent Excellent Inferior Excellent Excellent at 0 C Excellent Excellent Excellent Excellent - Excellent Excellent Storage stability at 40 C " " " " - " " TABLE 25

Example No. Reference Example No.

Properties of coating layer 28 29 30 31 31 32 22 Smothness Excellent Excellent Excellent Excellent Excellent Good Pencil hardness 2H H H F 2H 2B Gloss 92 86 87 87 74 65 Erichsen value (mm) > 7 > 7 > 7 > 7 > 7 > 7 Hardly Adhesion 100/100 100/100 100/100 100/100 coated 100/100 100/100 Adhesion after testing of water resistance 100/100 100/100 100/100 100/100 0/100 100/100 Anticorrosion (mm) 2.5 3.0 1.5 3.0 5.0 > 10 Degree of retention of gloss after testing of boiling water resistance 90 85 88 85 45 20 EXAMPLE 32 The polyester resin (B-37) (200 parts) and n-butyl cellosolve (50 parts) were charged into a vessel and were agitated at 150 to 1 700C for about 3 hours to give a viscous mixture. To the mixture was gradually added with vigorous agitation water (750 parts) over a period of about one hour to give a homogeneous, faint bluish white aqueous dispersion.

To the aqueous dispersion (1,000 parts) were added a 10% by weight aqueous solution (300 parts) of a non ironic surfactant (Nissan Nonione E-230, made by Nihon Yushi) and a 10% by weight aqueous solution (150 parts) of polyvinyl alcohol (GL-05, made by Nihon Gosei) to obtain a treating agent for giving drip-proof.

When this treating agent was allowed to stand at 400C for 2 months, any change of appearance was observed.

This treating agent was coated onto a polyethylene terephthalate film (thickness: 25 ) with a bar coater &num;18 in a thickness of 2 zz (in dry state), and dried at 1 050C for 5 minutes. The coating layer thus formed had excellent drip-proof.properties and had an adhesion: 100/100, adhesion after washing with water for one hour: 100/1 00, and further no change of transparency and drip-proof properties was observed.

EXAMPLES 33 AND 34 AND REFERENCE EXAMPLES 34 TO 36 In the same manner as described in Example 32, various treating agents for giving drip-proof were prepared by using the starting materials as shown in Table 26. The treating agents were coated onto a polyethylene terephthalate film to form a coating layer, iikewise. The properties of the coating layer are shown in Table 27.

TABLE 26

Example No. Reference Example No.

CompolTents (part by weight) 32 33 34 34 35 36 Polyester resin 8-37 B-38 8-39 8-40 8-41 8-42 200 200 200 200 200 200 Nonionic surfactant: Nissan Nonione E-230 30 40 - - 25 25 Nissan Nonione 515.4 - - 25 - - - Polyvinyl alcohol. 15 - 10 - - Water-soluble organic compounds: n-Butyl cellosolve 50 50 60 60 - - Isopropanol - - - - - So Water 1155 1110 1055 740 950 975 State of dispersion in water Excellent Excellent Excellent Inferior Excellent Excellent Stability (40 c, 2 months) Excellent Excellent Excellent - Excellent Excellent TABLE 27

Example No. reference Example No.

Properties of coating layer 32 33 34 35 36 Clouding* (%) 1 1 1 2 2 Dip-proof properties Excellent Excellent Excellent Excellent Excellent Adhesion 100/100 100/100 100/100 100/100 100/100 After Drip-proof Excellent Excellent Excellent Dissolved Peeled washing properties with flowing Adhesion 100/100 100/100 100/100 water for 1 hour Clouding (%) 1 1 1 *) Clouding, less than 10% = excellent transparency 10% or more = inferior transparency EXAMPLE 35 A woven fabric of 100% polyester spun was padded with the aqueous dispersion (X-1) and was squeezed at a squeezing degree of 70%, and thereafter, the resultant was dried at 1 200C for 5 minutes, soaped with a neutral detergent (0.2 g/liter) at 600C for 5 minutes, washed with water for 5 minutes, and dried with press. The thus treated woven fabric had properties as shown in Table 28.

EXAMPLE 36 The aqueous dispersion (X-1) (100 parts) and Sumitex M-3 (made by Sumitomo Chemical Co.) (4 parts) were mixed with agitation to give a treating agent.

In the same manner as described in Example 35 except that the treating agent as obtained above was used instead of the aqueous dispersion (X-1), a woven fabric was treated wherein the fabric was dried at 1 000C for 2 minutes and subjected to heat-treatment at 1 600C for 2 minutes. The properties of the fabric are also shown in Table 28.

REFERENCE EXAMPLE 37 Sumitex M-3 (100 parts), Sumitex AC-C (10 parts) and water (100 parts) were mixed with agitation to give a treating agent.

In the same manner as described in Example 35 except that the treating agent as obtained above was used instead of the aqueous dispersion (X-1), a woven fabric was treated. The properties of the fabric are also shown in Table 28.

TABLE 28

Example No. E Reference Example No. Properties of the treated fabric 35 36 37 Hardness* (mm) 58 67 70 Retention of hardness** after washing for 5 times (%) 75 80 45

*) It was measured by cantilever method.

**) Degree of retention of hardness after 5 times repeat of washing with a neutral detergent (1 g/liter) at 40-C for 10 minutes, washing with water for 10 minutes and drying with press in comparison with that before washing.

Claims (14)

1. An aqueous dispersion of a polyester resin which comprises: (A) a crystalline polyester having a melting point in the range of from 70 to 2000C and containing from 0.5 to 1 0% by mole of an aromatic dicarboxylic acid containing a metal sulfonate group as the polycarboxylic acid component, (B) a non-crystalline polyester having a softening point in the range, of from 40 to 2000C and containing from to 10% by mole of an aromatic dicarboxylic acid containing a metal sulfonate group as the polycarboxylic acid component, (C) a water-soluble organic compound having a boiling point in the range of from 70 to 2000C, and (D) water, the components (A), (B), (C) and (D) being incorporated in the disposition of the following water ratios:: (1) A/B = 0--95/1 00--5 (2) A+B/C/D = 10--70/22-40/220-88 (3) 0.02 < = C/C+D < 0.66

2. An aqueous dispersion as claimed in claim 1 wherein the crystalline polyester (A) has a molecular weight in the range of from 2,500 to 30,000 and a melting point in the range of from 70 to 2000C and comprises polycarboxylic acid components consisting of 40 to 99.5% by mole of an aromatic dicarboxylic acid containing no metal sulfonate group, 59.5 to 0% by mole of an aliphatic or alicyclic dicarboxylic acid containing 4 to 36 carbon atoms and 0.5 to 10% by mole of an aromatic dicarboxylic acid containing a metal sulfonate group, and polyol components consisting of 20 to 100% by mole of an aliphatic glycol containing 2 to 8 carbon atoms and/or an alicyclic glycol containing 6 to 12 carbon atoms and 80 to 0% by mole of bisphenol A ethylene oxide or propylene oxide adduct.

3. An aqueous dispersion which comprises: (B) a non-crystalline polyester having a molecular weight in the range of from 2,500 to 30,000 and a softening point in the range of from 40 to 2000C and comprising polycarboxylic acid components consisting of 40 to 99.5% by mole of an aromatic dicarboxylic acid containing no metal sulfonate group, 59.5 to 0% by mole of an aliphatic or alicyclic dicarboxylic acid containing 4 to 36 carbon atoms and 0.5 to 10% by mole of an aromatic dicarboxylic acid containing a metal sulfonate group, and polyol components consisting of 20 to 100% by mole of an aliphatic glycol containing 2 to 8 carbon atoms and/or an alicyclic glycol containing 6 to 12 carbon atoms and 80 to 0% by'mole of bisphenol A ethylene oxide or propylene oxide adduct, (C) a water-soluble organic compound.having a boiling point in the range of from 70 to 2000C, and (D) water, the componentrs (B), (C) and (D) being incorporated in the dispersion in the following weight ratio: (1)B+C+D=100 (2) B/C/D = 10-70/2740/20-88 (3) 0.02~C/C+D~0.66.

4. An aqueous dispersion as claimed in claim 1 or claim 2 wherein the crystalline polyester comprises 50 to 99.5% by mole of terephthalic acid or isophthalic acid as the polycarboxylic acid component and 85 to 100% by mole of ethylene glycol or butanediol as the polyol component.

5. An aqueous dispersion as claimed in any one of the preceding claims wherein the polyester (B) comprises 40 to 60% by mole of terephthalic acid as the polycarboxylic acid component and 20 to 60% by mole of ethylene glycol or butanediol as the polyol component.

6. An aqueous dispersion as claimed in any one of claims 1 to 4 wherein the polyester (B) is copolymerized with trimellitic acid or pyromellitic acid in an amount of 0.01 to 10% by mole based on the total polycarboxylic acid components.

7. An aqueous dispersion as claimed in any one of claims 1 to 4 wherein the polyester (B) is copolymerized with trimethylolpropane, trimethylolethane, glycerine or pentaerythritol in an amount of from 0.01 to 10% by mole based on the total polyol components.

8. An aqueous dispersion as claimed in any one of claims 1 to 4 wherein the polyester (B) is copolymerized with a polyalkylene glycol having a molecular weight in the range of from 106 to 10,000 in an amount of from 0.01 to 5% by weight based on the total weight of the polyol components.

9. An aqueous dispersion as claimed in any one of claims 1 to 3, wherein the glycol component of the non-crystal Fine polyester is a combination of ethylene glycol and neopentyl glycol in a molar ratio of 70: 30 to 30: 70.

1 0. An aqueous dispersion as claimed in any one of the preceding claims which additionally contains at least one amino resin, epoxy resin or isocyanate compound.

11. An aqueous dispersion as claimed in any one of the preceding claims wherein the watersoluble organic compound is an ethylene glycol monoalkyl ether or a monoalcohol having a boiling point of 1000C or above.

1 2. An aqueous dispersion as claimed in claim 1 substantially as hereinbefore described.

1 3. An aqueous dispersion as claimed in claim 3 substantially as hereinbefore described.

14. An aqueous dispersion as claimed in claim 1 substantially as hereinbefore described with reference to any one of the specific Examples.

1 5. An aqueous as claimed in claim 3 substantially as hereinbefore described with reference to any one of the specific Examples.

1 6. A coating composition, laminated product, aqueous printing ink, aqueous binder or surface treating agent which contains an aqueous dispersion as claimed in any one of the preceding claims.