Title of Invention	A BRANCHED HYDROXYL- FUNCTIONAL POLYESTER RESIN AND AN AQUEOUS DISPERSION AND A CROSS-LINKABLE BINDER COMPOSITION
Abstract	Branched hydroxyl-functional polyester resin having an average hydroxyl functionality of $m(g) 2, a hydroxyl number of 25 to 300 mg KOH/g, and a number average molecular weight within the range of from 500 to 3,000, which polyester resin comprises polyalkylene oxide groups and, optionally, sulphonate groups, characterised in that the polyester resin comprises the reaction product of: 1) a mixture of carboxylic acids comprising 50 to 80 mole % of an m- and/or p-aromatic and/or cycloaliphatic dicarboxylic acid, 20 to 50 mole % of an aliphatic dicarboxylic acid and/or aliphatic monocarboxylic acid with more than 6 carbon atoms, and, optionally, a tri- or higher-functional acid; and 2) a mixture of alcohols comprising an aliphatic diol with at least 4 carbon atoms and/or a cycloaliphatic diol with at least 4 carbon atoms, a C¿1?-C¿4? alkoxy polyalkylene oxide glycol and/or C¿1?-C¿4? alkoxy polyalkylene oxide 1,3-diol having a number average molecular weight of 500 to 3,000, and, optionally, a tri- or higher-functional polyalcohol, wherein the polyester resin has a carboxylic acid number of $m(F) 20 mg KOH/g ($m(F) 0.357 meq COOH groups per g of resin) and, optionally, a sulphonate number of $m(F) 4 mg KOH/g ($m(F) 0,070 meq sulphonate groups per g of resin), the acid groups being at least partly neutralised.

Title of Invention

A BRANCHED HYDROXYL- FUNCTIONAL POLYESTER RESIN AND AN AQUEOUS DISPERSION AND A CROSS-LINKABLE BINDER COMPOSITION

Abstract

Branched hydroxyl-functional polyester resin having an average hydroxyl functionality of $m(g) 2, a hydroxyl number of 25 to 300 mg KOH/g, and a number average molecular weight within the range of from 500 to 3,000, which polyester resin comprises polyalkylene oxide groups and, optionally, sulphonate groups, characterised in that the polyester resin comprises the reaction product of: 1) a mixture of carboxylic acids comprising 50 to 80 mole % of an m- and/or p-aromatic and/or cycloaliphatic dicarboxylic acid, 20 to 50 mole % of an aliphatic dicarboxylic acid and/or aliphatic monocarboxylic acid with more than 6 carbon atoms, and, optionally, a tri- or higher-functional acid; and 2) a mixture of alcohols comprising an aliphatic diol with at least 4 carbon atoms and/or a cycloaliphatic diol with at least 4 carbon atoms, a C¿1?-C¿4? alkoxy polyalkylene oxide glycol and/or C¿1?-C¿4? alkoxy polyalkylene oxide 1,3-diol having a number average molecular weight of 500 to 3,000, and, optionally, a tri- or higher-functional polyalcohol, wherein the polyester resin has a carboxylic acid number of $m(F) 20 mg KOH/g ($m(F) 0.357 meq COOH groups per g of resin) and, optionally, a sulphonate number of $m(F) 4 mg KOH/g ($m(F) 0,070 meq sulphonate groups per g of resin), the acid groups being at least partly neutralised.

Full Text	The invention relates to a branched hydroxyl-fictional polyester resin and an aqueous dispersion and a cross-linkable binder composition comprising the same. The resin has an average hydroxyl functionality of > 2, a hydroxyl number of 25 to 300 mg KOH/g, and a number average molecular weight within the range of from 500 to 3,000, which polyester resin comprises polyalkylene oxide groups and, optionally, sulphonate groups. Polyester resins and their use in two-component aqueous-based coating compositions are known from, int. al., EP-A-0 537 568 and WO 94/28043. The water-dilatable. polyesters disclosed therein contain both sulphonate and hydroxyl groups. Though high-quality coating layers can be obtained with the known aqueous-based coating compositions, the solids content of the aqueous polyester dispersions used in the known compositions is too low to be competitive in a great many applications, such as coating compositions to be used in automotive refinishing shops. The concentration of the polyester particles in the examples of both prior art publications does not exceed 35 wt. %. Furthermore, the storage stability of the aqueous polyester dispersions is inferior. Moreover, in order to emulsify the hydrophobic polyisocyanates in EP-A-0 537 568, frequently use has to be made of an external emulsifier, whereas in the examples of WO 94/28043 always use is made of polyisocyanate modified with polyethylene oxide glycol. A disadvantage of high water content is that the elimination of said water after the composition has been formed into, int. al, a coating layer requires a lot of time and energy. A further disadvantage of the known coating compositions is that the binder compositions exempHfied in WO 94/28043 are said to have a gel time of 3 to 6 hours, whereas on the other hand the curing speed of the binder compositions exemplified in WO 94/28043 is rather low (> 12 hrs at 50’C). The invention now provides a branched hydroxyi-functionai polyester resin having an average hydroxyl functionality of > 2, a hydroxy! number of 25 to 300 mg KOH/g, and a number average molecular weight within the range of from 500 to 3,000, which polyester resin comprises polyalkylene oxide groups and, optionally, sulphonate groups, characterised in that the polyester resin comprises the reaction product of 1) a module of cartxDxydc acids comprising 50 to 80 mole% of an m- and/or p-aromatic and/or cycioaliphatic dicarboxyiic acid, 20 to 50 mole% of an aliphatic dicariDoxylic acid and/or aliphatic monocarboxylic acid with more than 6 carbon atoms, and, optionally, a tri- or higher-functional acid, and 2) a mixture of alcohols comprising an aliphatic did with at least 4 carrion atoms and/or a cydoaliphatic diol with at least 4 carton atoms, a CrC4 alkoxy polyalkylene oxide glycol and/or CrC4 alkoxy polyalkylene oxide 1,3-diol having a number average molecular weight of 500 to 3,000, and, optionally, a tri- or higher-functional playschool, wherein the polyester resin has a carboxylic acid number of Also provided according to the invention is an aqueous dispersion comprising the branched hydroxyi-functionai polyester resin and an aqueous cross-linkable binder composition comprising the branched hydroxyi-functionai polyester resin and a organic hydrophobic polyisocyanate. Further provided according to the invention is the use of the aqueous cross-linkable binder composition in coating compositions, lacquer compositions, and adhesives. Finally, the present invention provides the use of such aqueous coating compositions in car refinish applications. The storage stability of the branched hydroxyl-functional polyester resin according to the invention is excellent Aqueous dispersions comprising the branched hydroxyl-functional polyester resin may have a solids content of more titan 45 Wl% at a viscosity of up to 5 Pa.s. The branched hydroxyl-functional polyester resin is able to disperse organic hydrophobic polyisocyanates in the absence of external emulsifiers. Aqueous cross-linkable binder compositions comprising a branched hydroxyl-functional polyester resin and an organic hydrophobic polyisocyanate have an acceptable pot life and cure speed. Aqueous coating compositions comprising the aqueous cross-linkable binder composition according to the present invention provide coatings having excellent properties like gloss, hardness, and distinctness of image (DOl). The branched hydroxyl-functional polyester resin can be prepared using conventional polymerisation procedures known to be effective for polyester resin synthesis. The reacBon to form the polyester resin may be conducted in one or more stages. In order to obtain a branched polyester resin, the conder’ati'on reaction is carried out in the presence of a branching agent, which may be a tri- or higher-functional acid and/or alcohol. For tiie tri- or higher-functional acid preference is given to an add selected from the group of trimelfiHc acid and pyromellitic acid or the anhydride thereof- For the tri- or higher’unctional polyalcohol preference is given to a polyalcohol selected from tine group of 1,1,1-trimethylol propane, 1,1,1-trimethylol ethane, 1,2,3-tiimethylol propane, pentaeryOirrtol, and mixtures thereof. More preferred is the use of a prior higher-functional playschool. Most preferred is the use of 1,1,1-trimethylol propane. If desired, the polyester resin may contain a proportion of carbonylamino linking groups -C(=0)-NH- (i.e. amide linking group) by including an appropriate amino-functional reactant as part of the "hydroxyl component" (such amide linkages are in fact useful in that Italy are more hydnDlysis-resistant and more hydrophilic.) In order to achieve hydroxyl functionality in the resulting polyester resin, a stoichiometric excess of the hydroxyl component should be used. Furthermore, in order to achieve an average hydroxyl functionality of > 2, preferably 2.3, more preferably 2.5, the polyester resin must have a branched structure. The mixture of carboxylic acids may comprise m-aromatic dicarboxylic acids, p-aromatic dicarboxylic acids, cycloaliphatic dicariDoxyiic acids, aliphatic dicariDoxylic acids with more than 6 carbon atoms, and aliphatic monocarboxyiic acid with more than 6 clarion atoms. Suitable dicarboxylic acids for obtaining excellent hydrolytic stability as well as excellent mechanical properties are m-aromatic dicarboxylic acids such as isophthalic acid, p-aromatic dicarboxylic acids such as terephthalic acid and dimethyl terephthalate, and cycloaliphatic dicarboxylic acids such as 1,4-cydohexane dicarboxyiic acid and hexahydrophthaiic anhydride. Mixtures of these dicarboxylic acids may also be used. Suitable aliphatic dicarboxylic acids with more than 6 carbon atoms include azelaic acid and sebacic acid. Suitable aliphatic monocarboxyiic acids with more than 6 carbon atoms include isononanoic acid, decanoic acid, 2-’thylhexyi cari’oxylic acid, and didecanoyl acid. Mixtures of these aliphatic dicarboxylic adds and/or aliphatic monocarboxyiic acids may also be used. Furthermore, the mixture of carboxylic acids may contain a small amount of an alkali salt of a sulphonic acid-substituted mono- or dicarboxylic acid or ester. Preferably, an alkali salt of a sulphonic acid-substituted dicarboxyfic acid or ester is used, such as sodium suiphosuccinic acid and 5-(sodium sulpho) isophthalic acid. The mixture of alcohols may comprise aliphatic diois with at least 4 carbon, atoms, cydoaliphatic diois with at least 4 carbon atoms, C1-C4 alkoxy potyalkyiene oxide glycols and/or C1-C4 alkoxy polyalkylene oxide 1,3-diols having a number average molecular weight of 500 to 3,000. Suitable (cyclo)aliphatic diois for the preparation of the hydroxyl-functional polyester resin are diois having at least 4 carbon atoms such as 1,4-butane diol, 1,6-hexane diol, 2,2-dimethyl-1,3-propane diol, 2-ethyl-2-propyl-1,3-propane diol. 1,2-, 1,3-, and 1,4-cyclohexane diois, the corresponding cyclohexane dimethanol, and mixtures thereof. In order to incorporate a hydrophobic organic polyisocyanate into the aqueous polyester resin dispersion without the use of external emulsifiers, tie polyester resin should comprise a C1-C4 alkoxy polyalkylene oxide group. The preferred alkylene oxide groups are ethylene oxide groups, but alternatively propylene oxide groups or mixtures of ethylene oxide and propylene oxide groups are useful as well. For example, the alkylene oxide groups may be C1-C4 alkoxy ethers of polyalkylene glycols witty the structure: wherein R1 is a hydrocarbon radical with 1 to 4, preferably 1 or 2, carbon atoms; R2 is a metiiyl group; x is between 0 and 40, preferably between 0 and 20, most preferably between 0 and 10; y is between 0 and 50, and x+y is between 2 and 50, preferably between 2 and 25. The distribution of the alkylene glycols may be at random, alternating distribution or blocked. Examples are Ci-C4 alkoxy polyC2{C3)alkylene oxide glycol and/or CrC4 alkoxy polyC2{C3)aIkylene oxide 1,3-diol, wherein polyC2(C3)alkylene oxide stands for polyethylene oxc, optionally comprising propylene oxide units. Preferably the polyester resin comprises 2.5 to 15 wt.% C1-C4 alkoxy pofyalkyiene oxide groups with a number average molecular weight of 500 to 3,000, preferably between 500 and 1,500, most preferably between 500 and 1,250, while preference is given to a polyester resin comprising 5 to 10 wt.% of CI-CA alkoxy polyalkylene oxide groups. Optimum result are obtained with a polyester resin wherein the polyalkylene oxide units are polyethylene oxide units. Suitable CrC4 alkoxy polyalkylene oxide compounds contain at least one hydroxyl group. Examples are methoxy polyC2(C3)alkylene oxide glycols and methoxy polyC2(C3)alkylene oxide"1,3-diols, such as Tegomer® D-3123 (PO/EO = 15/85; Mn = 1,180). Tegomer® D-3409 (PO/EO = 0/100; Mn = 2,240), and Tegomer® D-3403 (PO/EO = 0/100; Mn = 1,180) available from Goldschmidt AG, Germany, and MPEG 750 and MPEG 1000. Optionally, aminoalcohol may be used in the preparation of the polyester resin. Examples of mono-alcohois include n-hexanol, 2-ethyl hexanol, cyclohexanol, tell butyl cyclohexanol. stearyl alcohol, dodecagon, and mobsters thereon. The polyester resin has a carboxylic add number of number of The polyester resin has a hydroxyl number of 25 to 300 mg KOH/g. preferably 50 to 250 mg KOH/g, more preferably 100 to 220 mg KOH/g. The polyester resin has a number average molecular weight within the range of from 500 to 3,000, preferably 750 to 2,500, more preferably 1,000 to 2,000. At the end of the polycondensation reaction the carboxylic acid groups of the polyester resin are at least partially neutralized with a neutralising agent, after which water is added, preferably to the hot melt at a temperature starting at 100 to 110’0, after which the temperature is gradually lowered to ambient temperature. The aqueous polyester resin dispersion obtained in this manner may have a solids content of more than 45 wL%, preferably 45 to 65 wL%, more preferably 50 to 60 wL%, at a viscosity of up to 5 Pa.s, preferably 0.1 to 3 Pa-S. The average particle size of the thus obtained dispersion is in the range of 30 to 300 nm, and preferably in the range of 50 to 200 nm. The thus obtained dispersion has a pH between 6 and 9, preferably between 6.5 and 8. Examples of neutralising agents include alkali metal hydroxides, such as sodium hydroxide, potassium hydroxide, or lithium hydroxide, ammonia, and amines. Suitable amines include primary, secondary, and tertiary amines. Suitable primary amines are, for example, isopropyl amine, butyl amine, ethanol amine, 3-amino-1-propanol, 1-amino-2-propanol, 2-amino-2-methyl"1-propanol or 2-amino-2-methyH,3-propane diol Secondary amines that can be used are, for example, morpholine, diethyl amine, dibuty! amine, N-methy ethanol amine, dietitian amine, or dfisopropanol amine. Examples of suitable tertiary amines include trimethyl amine, triethyl amine, triisopropyl amine, triisopropanol amine, N,N-dimethyl ethanol amine, dimethyl isopropyl amine, N,N-diethyl ethanol amine, 1-dime1tiyl amino-2-propanol, 3-dimethyl amino-1-propanol, 2-dimethyl amino-2-methyH-propanol, N-methyl dimethanol amine, N-methyl dimethanol amine, N-butyl dimethanol amine, N-ethyl morpholine. Tertiary amines are preferred. More preen-ed is N,N-dimethyl ethanol amine. The invention relates also to an aqueous cross-linkable binder composition comprising A) at least one branched hydroxyl-functional polyester resin and B) at least one organic hydrophobic polyisocyanate. The organic hydrophobic polyisocyanate (component B) includes polyfunctional, preferably free polyisocyanates with an average NCO functionality of more than 2, preferably 2.5 to 5, and may be (cyclo)aliphatic, araliphatic or aromatic in nature. Preferably, the hydrophobic organic polyisocyanate has a viscosity at 22’0 of 0.1 to 5 Pa.s. Examples of hydrophobic organic polyisocyanates include 1,6-diisocyanatohexane, isophorone diisocyanate, 2,4-toIuene diisocyanate. 2,6-toiuene diisocyanate, diphenyl methane-diisocyanate, 4,4'-bis(isocyanato-cyclohexyl) methane, 1,4-diisocyanatobutane, 1,5-diisocyanato-2,2-dimethyl pentane, 2,2,4-trimethy!-1,6-diisocyanatohexane, 1,10-dilsocyanatodecane, 4,4-diisocyanato-cyciohexane, 2,4-h6xahydrotoluene disocyanate, 2,6- hexahydrotoluene diisocyanate, norbomane diisocyanate, 1.3-xylylene diisocyanate, 1,4-xyfylene diisocyanate, 1-isocyanato-3-(isocyanato methyl)-1-methyl cyclohexane, m-a,a-a' ,a'-tetrame11iyl xylylene diisocyanate, and mixtures thereof. The hydrophobic polyisocyanate may include beret, refinance, uretdione, and isocyanurate derivatives of the above-mentioned compounds. Normally, these products are liquid at ambient temperature and commercially available in a wide range. Particularity preferred isocyanate curing agents are diisocyanates and adducts. Examples thereof are 1,8-diisocyanato-4-(isocyanatomethyl) octane, the adduct of 3 moles of toluene diisocyanate to 1 mole of trimethylol propane, the isocyanurate trimmer of 1,6-diisocyanatohexane, the isocyanurate trimer of isophorone diisocyanate, the uretdione dimer of 1,6-diisocyanatohexane, the biuret trimer of 1,6-diisocyanatohexane, the adduct of 3 moles of m-a,a-a\a'-tetramethylc xylene diisocyanate to 1 mole of trimethylol propane, and mixtures thereof. More preferred are the isocyanurate and redbones of 1,6-hexane diisocyanate and isophorone diisocyanate. Usually these compounds contain small quantities of their higher homologues. Optionally, the aqueous cross-linkable binder composition may also comprise an organic hydrophilic polyisocyanate compound substituted with non-ionic groups, such as the above-mentioned C1-C4 alkoxy polyalkylene oxide groups. Preferably, 30 wt.% of non-ionic groups may be present on total solid polyisocyanate corporal, i.e. organic hydrophobic and hydrophilic polyisocyanate, more preferably 20 wt%, most preferred 15 wL%, Preferred are the isocyanurate of 1,6-hexane diisocyanate and isophorone diisocyanate substituted within methoxy polyetiiylene glycol. The polyisocyanate and the aqueous polyester resin dispersion should be mixed in such a ratio that the NCO;OH ratio is in the range of 0.5-3:1, preferably 0.75-2.5:1, and more preferably 1-2:1. The organic hydrophobic polyisocyanate compound B) and, optionally, the organic hydrophilic polyisocyanate may be mixed into component A) by any suitable technique. However, simply stirring is usually sufficient Sometimes It may be useful to dilute the polyisocyanate somewhat with an organic solvent like butyl acetate or 1-meftoxy-2-propyl acetate to reduce the viscosity of the polyisocyanate. The binder composition may contain catalysts like amines and Sn-based catalysts, such as dibutyl tin dilaurate and dibutyl tin acetate. The pot life at ambient temperature usually is between 4 and 12 hours, depending on the use of the catalysts and their amount The coating compositions may further comprise other ingredients, additives or auxiliaries, such as other polymers or polymer dispersions, pigments, dyes, emulsifiers (surfactants), pigment dispersion aids, wetting agents, levelling agents, anti-catering agents, antifoaming agents, ant sagging agents, heat stabilisers, UV absorbers, antioxidants, and fillers. Suitable types of other polymer dispersions include acrylic polymer emulsions and aqueous polyurethane dispersions. Also included in the binder .or coating compositions of the invention may be reactive diluents such as water-soluble mono- or (preferably) polyhydric alcohols. Examples of monohydric alcohols include hexyl glycol, butoxyelhanol, 1-’ethoxy-propanol-2, 1-ettioxy-propanol-2, .1-propoxy-propanol-2, 1-butoxy-propanol"2, 2-methoxybutanol, 1-isobutoxy-propanoI-2, dipropylene glycol monomethyl ether, diacetone alcohol, methanol, ethanol, propanol. isopropanol, butanol, 2-butanol, pentanol, hexanol, benzyl alcohol, and mixtures thereof. Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, propylene glycol, isomeric butane diols, the polyethylene oxide glycols or polypropylene oxide glycols, 1,1,1 -trimethylol propane, 1,2,3-trimethylol propane, pentaerythritol, glycerol, and mixtures thereof. The composition of the present invention consists essentially of water, being an aqueous composition. However, about 20 wt.% of liquid content of the composition may be an organic solvent. As suitable organic solvents may be mentioned dimethyl dipropylene glycol, methyl ether of diacetone alcohol, ethyl acetate, butyl acetate, ethyl glycol acetate, butyl glycol acetate, l-methoxy-2- propyl acetate, butyl propionate, ethoxy ethyl propionate, toluene, xylene; methyl ethyl ketone, methyl isobutyl ketone, methyl Amy! ketone, ethyl amyl ketone, dioxolane, N-methyl-2-pyrrolidone, dimethyl carbonate, propylene carbonate, butyrolactone, caprolactone, and mixtures thereof. The volatile organic content of the composition may range from 0 to 400 g/l, preferably from 0 to 250 g/l. The coating composition of the present invention may be applied to any substrate. The substrate may_ be, for example, metal, plastic, wood, glass, ceramic, or some other coating layer. The other coating layer may be comprised of the coating composition of the current invention or it may be a different coating composition. The coating compositions of the current invention show particular utility as clear coats, base coats, pigmented top coats, primers, and fillers. The coating compositions can be applied by conventional means such as by spray gun, brush, or roller, spraying being preferred. Curing temperatures preferably are between 0 and 80°C and more preferably between 10 and 60°C. The compositions are particularly suitable in the preparation of coated metal substrates, such as in the refinish industry, in particular the body shop, to repair automobiles and transportation vehicles, and in finishing large transportation vehicles such as trains, trucks, buses, and aero planes. Preferred is the use of the coating composition of the present invention as a clear coat. Clear coats are required to be highly transparent and must adhere well to the base coat layer. It is further required that the clear coat does not change the aesthetic aspect of the base coat by strike-in, i.e. discolourations of the base coat due to its solvation by the clear coat composition, or by yellowing of the clear coat upon outdoor exposure. A clear coat based on the coating composition of the present invention does not have these drawbacks. In the case of the coating composition being a clear coat tiie base coat may be a conventional base coat known in the coating art Examples are solvent bome base coats, e.g., Autobase® ex Akzo Nobel Coatings BV, based on cellulose acetobutyrate and acrylic resins, and water bome base coats, e.g., Autowave® 0 ex Akzo Nobel Coatings BV, based on an acrylic.resin dispersion. Furthermore, the base coat may comprise pigments (colour pigments, metallics and/or pearls), wax, solvents, flow additives, neutralising agent, and defoamers. Also high solids base coats can be used. These are, for instance, based on polyols, imines, and isocyanates. The clear coat composition is applied to the surface of a base'coat and then cured. An intermediate curing step for the base coat may be introduced,. The invention will be illustrated with reference to the following examples. Of course these examples are submitted for a better understanding of the invention only; they are not to be construed as limiting in any manner the scope thereof. Examples In the following examples, the preparation of a number of water borne polyester resin dispersions and binder compositions according to the invention is disclosed. The properties measured on these dispersions are listed in Table 1. The dispersions' average particle size given in to table was detemnined with the aid of dynamic fight scattering, with tiie dispersions diluted to a solids content of about 0.1 wL%. The viscosity was determined with a Brookfield viscometer (LV - 4; 60 revolutions per minute). The solids content was determined in accordance with ASTM motion no. 1644-59, within heating to MO'‘C over a period of 30 minutes. The Mn was measured with GPC with polystyrene as standard. Preparation of branched water borne polyester resin dispersions Example 1: Preparation of the branched polyester resin A 3 I flask fitted with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet was charged with a mixture composed of: 597.6 g of sebacic acid 398.4 g of isophthalic acid 426.2 g of 1,4-cyclohexane dimethyl ol 314.5 g of 2,2-dimethyl-1,3-propane diol 246.5 g of 1,1,1-trimethylol propane 0.25 g of Fascist 41 GO (Sn-based catalyst) After deaeration, the flask was brought under a nitrogen atmosphere. The contents of the flask were heated to 150°C, whereupon tiie temperature was gradually increased to 200°C over a period of 2 hours. The temperature of 200°C was maintained in the flask until a clear reaction melt was obtained. After the collection of 171 ml water of distillation, a clear reaction mixture was obtained. The mixture was cooled to 140’0, after which the following components were added: 172.6 g of isophthalic acid and 180 g of methoxy polyethylene oxide glycol (Mn = 750). The reaction McClure was gradually heated to 210°C and kept at this temperature until an acid value of 14.9 mg KOH/g was obtained. The practical OH-value was 139.0 mg KOH/g, the OH-functionality was 3.0, and = 1,376. Example la: Preparation of a dispersion from the branched polyester resin of Example 1 A 2 1 flask fitted within a stirrer, a thermometer, a reflux condenser, and a dropping funnel was filled with 500 g of tiie polyester resin of Example 1. The contents of the flask were heated to 110°C, at which temperature tiers were added: 9.5 g of N,N-dimethyl ethanol amine (con'esponding to a neutralizations degree (N.R.) of the carboxylic groups of 80%) and subsequently, over a period of 3 hours: 433.9 g of Demineralised water, after which the temperature was gradually decreased from 100°C to 30°C. The properties of the thus obtained water borne polyester resin dispersion are given in Table 1. Example lb: Preparation of a dispersion from the branched polyester resin of Example 1 In a manner analogous to that disclosed in Example la, a dispersion was prepared, with the proviso that this time the following ingredients were added to tine flask containing 500 g of tiie polyester resin of Example 1: 8.9 g of N,N-dimethyl eternal amine and 383.9 g of demineralized water. The properties of the thus obtained water borne polyester resin dispersion are given in Table 1. Example 2 In a manner analogous to that disclosed in Example 1, a polyester resin was prepared, with the proviso that this time the flask was charged with: 597.6 g of sebacic acid 398.4 g of isophthalic acid 426.2 g of 1,4-cyclohexane dimethyl ol 253.2 gof2,2-dimethyl-1.3-pnDpanediol 321.5 g of 1,1,1-trimethyloi propane 0.25gofFascat4100 After a dear reaction mixture had been obtained, there were added: 185.9 g of isophthalic acid and 180 g of methoxy polyethylene oxide glycol (Mn = 750). The end product had an acid number of 13.0 mg KOH/g, a practical OH-value of 147, an OH-functionality of 3.25, and a Mn of 1,487. Example 2a Example 1 a was repeated, with the proviso that the flask was charged with: 500 g of the polyester resin of Example 2, after which there were added 8.3 g of N,N-demurely ethanol amine and 472.1 g of Demineralised water. The properties of fire thus obtained water borne polyester resin dispersion are given in Table 1. Example 2b In a manner analogous to that disclosed in Example 2a, a dispersion was prepared, with the proviso that this time the following ingredients were added to the flask containing 500 g of polyester resin of Example 2: 7.25 g of N,N-dimethyl ethanol amine and 370 g of Demineralised water. The properties of the thus obtained water borne polyester resin dispersion are given in Table 1. Example 3 In a manner analogous to that disclosed in Example 1, a polyester resin was prepared, with the proviso that this time the flask was charged with: 409.0 g of sebacic acid 237.0 g of isononanoic add 503.0 g of tsophthanc add 399.6 g of 1,4-cydohexane trimethylol 82.0 g of 2,2-dimethyl-1,3-propane diois 496.5 g of 1,1,14rimethyfo( propane 0.25 g of Fascist 4100 After a clear reaction mixture had been obtained, there were added: 161.8 g of isophthalic acid and 191.3 g of methoxy polyethylene oxide glycol (Mn = 750). The end product had an acid number of 14.0 mg KOH/g, a practical OH-value of 136, an OH-functionality of 3, and a Mn of 1,370, Example 3a Example la was repeated, with the proviso that the flask was charged with: 500 g of the polyester resin.of Example 3, after which there were added 8.35 g of N,N-dimethyl ethanol amine and 462.5 g of Demineralised water. The properties of the tries obtained water borne polyester resin dispersion are given in Table 1. Example 3b In a manner analogous to that disclosed in Example 3a, a dispersion was prepared, with Vr\e proviso that \h\s time the following ingredients were added to c the flask containing 500 g of the polyester resin of Example 3: 7.2 g of N,N-dimethyl ethanol amine and 377.8 g of demineralised water. The properties of IMe thus obtained water borne polyester resin dispersion are given in Table 1. Example 4 In a manner analogous to that disclosed in Example 1, a polyester resin was prepared, within the proviso fiat this time the flask was charged with: 348.5 g of sebacic acid 237.0 g of isononarxDJc acid 552.8 g of isophthalic acid 399.6 g of 1,4-cydohexane trimethylol 82.0 gof2,2-dimethyl-1,3-propanediol 496.5 g of 1,1.1-trimethylol propane 0.25gafFascat4100 After a clear reaction mixture had been obtained, there were added: 161.8 g of isophthalic acid and 191.3 of methoxy polyethylene oxide glycol (Mn = 750). The end product had an acid number of 13.5 mg KOH/g, a practical OH-value of 136, an OH-functionality of 3, and a Mn of 1,381. Example 4a Example 1a was repeated, with the proviso that the flask was charged with: 500 g of the polyester resin of Example 4, after which there were added 6.45 g of N,N-dimethyl ethanol amine and 370.7 g of demineralised water. The properties of the thus obtained water home polyester resin dispersion are given in Table 1. Example 5 In a manner analogous to that disclosed in Example 1, a polyester resin was prepared, with the proviso that this time the flask was charged with: 597.6 g of sebacic add 398.4 g of isophthalic acid 569.1 9 of 2,2-dimethyl-1,3"propane did 321.6 g of 1,1,1-trimethylol propane 0.25 g of Fascat4100 After a clear reaction mixture had been obtained, there were added: 199.2 g of Isophtiiaiic acid and 168 g of methoxy polyethylene oxide glycol (Mn = 750). The end product had an acid number of 14.6 mg KOH/g, a practical OH-value of 151, an OH-functionarrty of 3.5, and a Mn of 1,443. Example 5a Example 1a was repeated, with the proviso that the flask was charged with: 500 g of the polyester resin of Example 5, after which there were added 8.1 g of N,N-dimethyl ethanol amine and 417.8 g of demineralised water. The properties of the thus obtained water bome polyester resin dispersion are given in Table 1. Example 6 In a manner analogous to that disclosed in Example 1, a polyester resin was prepared, with the proviso that this time the flask was charged with: 348.4 g of sebacic acid 237.0 g of isononanoic acid 550.4 g of isophthalic acid 376.7 g of 2,2-dimethyl-1,3-propane diol 504.5 g of 1,1,1 "trimethylol propane 0.25gofFascat4100 After a dear reaction mixture had been obtained, there were added: 186.7 g of isophthalic acid and 180 g of methoxy polyethylene oxide glycol (Mn = 750). The end product had an acid number of 13.3 mg KOH/g, a practical OH-value of 135, an OH-functionality of 3.5, and a Mn of 1,352. Example 6a Example 1a was repeated, with the proviso that the flask was charged with: 500 g of the polyester resin of Example 6, after which there were added 6.9 g of N,N”dimethyl ethanol amine and 402.2 g of demineralised water. Tithe properties of the thus obtained water bome polyester resin dispersion are given in Table 1. Example 7 In a manner analogous to that disclosed.in Example 1, a polyester resin was prepared, with the proviso that this time the flask was charged with: 21.4 g of 5-{sodium siphon) isophtiialic acid 192.6 g of isophthalic acid 426.2 g of 1.4-cyclohexane dimethyl 253.4 g of2,2-dimethyi-1,3-propanediol 321.6 g of 1,1,1-trimethylol propane 25.0 g of demineralised water 0,25gof Fascat4100 The homogenised mixture was gradually heated to 180°C and kept at this temperature until a clear mixture had been obtained. After 62 ml water of distillation had been collected, the clear reaction mixture was cooled to 140°C. At this temperature tiers were added: 597.9 g of sebacic acid and 192.5 g of isophthalic add. After tiie temperature of tiie reaction mixture had been gradually increased to 195°C, the mixture was kept at this temperature until 201 ml water of distillation had been collected and a clear reaction melt obtained. After the reaction mixture had been cooled to 140’0, the following components were added; 172.6 g of isophthalic acid and 180.0 g of methoxyl polyethylene oxide glycol (Mn = 750). The reaction mixture was gradually heated to 215°C and kept at said temperature until an acid value of 6.7 mg KOH/g was obtained. The practical OH-value was 144. the OH-functionality was 3.25, and the molecular weight Mn = 1,593, Example 7a Example la was repeated, with the proviso tilt the flask was charged with: 500 g of the polyester resin of Example 7, after which Tiered were added 3.2 g of N,N-dimethyl ethanol amine and 496.8 g of demineralised water. The properties of the thus obtained water borne polyester resin dispersion are given in Table 1. Example 7b Example 7a was repeated, except that this time: 1.6 g of N,N-dimethyl ethanol amine and 424.3 g of demineralised water were added. The properties of the obtained polyester resin dispersion are given In Table 1. Example 8 In a manner analogous to that disclosed in Example 7, a polyester resin was prepared, with proviso that this time the flask was charged with: 194.2 g of isophthalic acid 16.1 g of 5-{sodium sulpho) isophthalic acid 579.1 g of 2,2-dimethyl-1,3-propane diol 321.6 g of 1,1,1 -trimethyiol propane 20.0 g of demineralised water 0.25gofFascat4100 After a clear reaction mobsters had been obtained, there were added: 194.2 g of isophthalic acid and 597.9 g of sebacic acid. After this reaction mixture became clear, the following components were added: 185.9 g of isophthalic acid and 168-0 g of methoxy polyethylene oxide glycol (Mn = 750). The end product had an acid number of 8,4 mg KOH/g, a practical OH-value of 150 mg KOH/g, an OH-functionality of 3.5, and a Mn of 1,875. Example 8a Example la was repeated, with the proviso that the flask was chained wilt: 500 g of the polyester resin of Example 8, after which there were added 2.7 g of N,N-dimethyl ethanol amine and 497.3 g of demineralised water. The properties of the thus obtained water borne polyester resin dispersion are given in Table 1. Example 9 In a manner analogous to that disclosed in Example 7, a polyester resin was prepared, with the proviso that this time the flask was charged with: 269.9 g of isophthalic acid 17.1 g of 5-{sodium sulpho) isophthalic acid 376.7 gof2,2"dimethy!-1.3-propanediol 504.5 g of 1,1,1-trimethylol propane 25.0 g of demineralised water 0.25gof Fascat4100 /Meter a dear reaction mixture had been obtained, there were added: 269.8 g of isophtinallc acid 348.4 g of sebacic acid 237.0 g of isononanoic acid. After this reaction obscure became clear, the following components were added: 174.3 g of isophthalic acid and 180.0 g of methoxy polyethylene oxide glycol (Mn = 750). The end product had an acid number of 6.7 mg KOH/g, a practical OH-value of 134 mg KOH/g, an OH-functionality of 3.25, and a Mn of 1,548. Example 9a Example 1a was repeated, wifely the proviso that the flask was charged with: 500 g of the polyester resin of Example 9, after which there were added 2.13 g of N.N-dimethyl ethanol amine and 459.4 g of demineralised water. The properties of the thus obtained water bome polyester resin dispersion are given in Table 1. Example 10 In a manner analogous to that disclosed in Example 7, a polyester resin was prepared, with the proviso that this time the flask was charged with: 219.1 g of isophthalic acid 21,4 g of 5-(sodium sulpho) isophtiialic acid 426.2 g of 1,4-cyciohexane dimethylol 253.4 g of 2,2-dimethyl-1,3-propane diol 321.6 g of 1,1.1-trimethylol propane 25.0 g of demineralised water 0.25 g of Fascist 4100 After a clear reaction mixture had been obtained, there were added: 219.1 g of isophthalic acid and 533.3 g of sebacic acid. After friars reacBon mixture became clear, the following components were added: 172,6 g of isc’hthalic acid and 1 BO.O g of methoxy polyethylene oxide glycol (Mn = 750). The end product had an acid number of 6.5 mg KOH/g, a practical OH-value of 145 mg KOH/g, an OH-functionality of 3.25, and a Mn of 1,817. Example 10a Example 1a was repeated, with the proviso that the flask was charged with: 500 g of the polyester resin of Example 10, after which there were added 1.55 g of N,N-dime1hyl eternal amine and 478.8 g of demineralised water. The properties of the thus obtained water borne polyester resin dispersion are given in Table 1. Example 11 In a manner analogous to that disclosed in Example 7, a polyester resin was prepared, with the proviso that this time a 2 1 flask was charged with: 145.7 g of isophthalic acid 13.0 g of 5-(sodium siphon) isophthalic acid 266.4 g of 1.4-cycIohexane dimethylol 152.3 g of 2,2-dimethyl-1,3-propanediol 201.0 g of 1,1,1 "trimethylol propane 35.0 g of demineralised water 0.70gof Fascat4100 After a clear reaction mixture had been obtained, there were added: 145.7 g of isophthalic acid and 266.3 g of sebacic add. After this reaction mature became clear, the following components were added: 145.7 g of isophthalic add and 111.0 g of methoxy polyethylene oxide glycol (Mn = 1,000). The end product had an add number of 8,0 mg KOH/g, a practical OH-value of 146 mg KOH/g, an OH-functionality of 3.5, and a Mn of 1,773. Example 11a Example 1a was repeated, with the proviso that a 1 1 flask was charged with: 250 g of ttie polyester resin of Example 11, after which there were added 1.0 g of N,N-dimethyl ethanol amine and 196.4 g of demineralised water. The properties of the thus obtained water borne polyester resin dispersion are given in Table 1. Example 12 In a manner analogous to that disclosed in Example 7, a polyester resin was prepared, within the proviso that this time a 21 flask was charged with: 160.3 g of isophfrialic add 13.0 g of 5-{sodium sulpho) isophthafic acid 266.4 g of 1,4-cydohexane dimethylol 152,3 g of 2,2-dimethyH,3’ropane diol 201.0 g of 1,1.1-trimethylol propane 35.0 g of demineralised water 0.70gof Fascat4100 After a clear reaction mixture had been obtained, there were added: 160.3 g of isophthalic add and 212.9 g of sebacic dd. After this reaction mixture became clear, the following components were added: 160.3 g of isophthalic add and 109.0 g of methoxy polyethylene oxide glycol (Mn = 1,000), The end product had an acid number of 8.0 mg KOH/g, a practical OH-value of 147 mg KOH/g, an OH-functionality of 3.5, and a Mn of 1,767 Example 12a Example la was repeated, with the proviso that a 11 flask was charged with: 250 g of the polyester resin of Example 12, after which there were added 1.0 g of N,N-dimethyl ethanol amine and 196.4 g of demineralised water. The properties of the thus obtained water borne polyester resin dispersion are given in Table 1. Example 13 In a manner analogous to that disclosed in Example 7, a polyester resin was prepared, with the proviso that this time a 2 1 flask was charged with: 171.0 g of isophthalic acid 13.0 g of 5-(sodium sulpho) isophthalic acid 266.4 g of 1,4-cydc’exane dimethylol 150.8 gof2,2-dimethyi-1,3-propanediol 201.0 g of 1,1,1 -trimethylol propane 35.0 g of demineransed water 0.70 g of Fascist 4100 After a clear reaction brute had been obtained, there were added: 169.6 g of isophthalic acid and 177.6 g of sebacic acid. After a clear reaction mixture had been obtained, there were added: 169.6 g of isophthalic acid and 109.0 g of methoxy polyethylene oxide glycol (Mn = 1,000). The end product had an acid number of 5,1 mg KOH/g, a practical OH-value of 144 mg KOH/g, an OH-functionality of, and a Mn of 1908. Example 13a Example la was repeated, with the proviso that a 11 flask was charged with: 250 g of the polyester resin of Example 13. after which there were added 0.6 g of N,N-dimethyl ethanol amine and 250 g of demineralised water. The properties of the thus obtained water bome polyester resin dispersion are given in Table 1. Example 14 in a manner analogous to that disclosed in Example 7, a polyester resin was prepared, with the proviso that this time a 6 I flask was charged with: 385.1 g of isophthalic add 42,9 g of 5-(sodium siphon) isophthalic acid 852,5 g of 1,4-cyclohexane dimethylol 1265 g of 1.1.1 "trimethyiol propane 50.0 g of deminerailsed water O.SOgof Fascat4100 After a clear reaction mixture had been obtained, there were added: 385.1 g of isophthafic acid and 1195.8 9 of sebacic acid. After fries reaction McClure became clear, the following components were added: 345.3 9 of isophfriafic acid and 360.0 g of methoxy polyethylene oxide glycol (Mn = 750). The end product had an acid number of 6.4 mg KOH/g, a practical OH-value of 199 mg KOH/g, an OH-functionality of 4.9, and a Mn of 1,771 Example 14a Example 1 a was repeated, with the proviso that the 21 flask was charged with: 500 g of the polyester resin of Example 14, after which there were added 1.5 g of N,N-dimethyl eternal amine and 425.9 g of demineralised water. The properness of the. thus obtained water borne polyester resin dispersion are given in Table 1. Example 15 In a manner analogous to that disclosed in Example 7, a polyester resin was prepared, with the proviso that this time a 2 I flask was charged with: 145.7 g of isophthalic acid 13,4 9 of 5-{sodium sulpha) isophthalic acid 266.4 g of 1,4-cydohexane dimethylol 395.3 g of 1,1,1-trimethyiol propane 35.0 g of demineralised water 0,70 g of Fascist 4100 After a clear reaction mixture had been obtained, there were added: 145.7 g of isophthaiic acid and 266.3 g of sebacicacid. After this mixture became clear, the following components were added: 145.7 g of isophthaiic acid and 114.0 g of metfioxy polyethylene oxide glycol (Mn = 1,000). The end product had an acid number of 6.4 mg KOH/g, a practical OH-value of 200 mg KOH/g, an OH-unisonant of 5.1, and a Mn of 1,801, Example 15a Example 1a was repeated, with the proviso that the flask was charged with: 250 g of the polyester resin of Example 15, after which there were added 0.8 g of N,N-dimethyl ethanol amine and 221.7 g of deminerailsed water. The properties of the thus obtained water borne polyester resin dispersion are given in Table 1. Example 16 In a manner analogous to that disclosed in Example 7, a polyester resin was prepared, with the proviso that this time the 2 I flask was charged with: 171.0 g of isophthaiic acid 13.4 g of 5-(sodium sulpho) isophthaiic acid 266.4 g of 1,4-cydohexane dimethylol 395.3 g of 1,1,1-trimethylol pupae 35.0 g of deminerailsed water 0.70gof Fascat4100 After a clear reaction mixture had been obtained, there were added: 169.5 g of isophthaiic acid and 177.6 g of sebacicacid. After this reaction mixture became clear, the components were added: 169.6 g of isophthaiic acid and 112.5 g of methoxy polyethylene oxide glycol (Mn = 1,000). The end product had an acid number of 7.9 mg KOH/g, a practical OH-value of 204 mg KOH/g, an OH-fundfonallty of 5.1, and a Mn of 1,893. Example ISa Example 1a was repeated, with the proviso that the flask was charged with: 250 g of the polyester resin of Example 16, after which there were added 0.9 g of N.N-dimethyl ‘howl amine and 270.8 g of demlrrerallsed water. The properties of the obtained polyester resin dispersion are given in Table 1 and la. Examples 17 to 48 The aqueous polyester resin dispersions (component A) were mixed with poly-functional isocyanate cross-linkers (component B) in a ratio NCO:OH = 1.5. The polyester resin dispersions were diluted with butyl glycol (10 wt.% on solids). The isocyanate components were diluted with methoxy isopropyl acetate (80 wL% on solids). For the isocyanate cross-linkers use was made of two potyisocyanates, both commercially available from Bayer a) Desmodur LS 2025 (a hydrophobic isocyanurate based on 1,6- hexamethyiene ditsocyanate). and b) Bayhydur LS 2032 (a hydrophiiic isocyanurate based on 1,6-hexamethylene diisocyanate, modified with about 12 wt.% of methoxy polyethylene oxide glycol). No use was made of a catalyst. The mixtures with LS 2025 according to the invention all had a solids content of more than 50 wt.%, whereas the mixtures with the hydrophiiic LS 2032 (comparison) had a maximum achievable solids content of between 40 and 45 wt%. The mixtures of polyester resin dispersions and the isocyanate components were applied on glass panels in a dry layer thickness between 60 and 80 p.m- The panels were allowed to dry at ambient (room) temperature (RT) for one week. The Pesos Hardness was determined in accordance with French industrial standard method NF T30-O16, the result being expressed in seconds, and is given in Table 2. The hardness of the coating layers prepared with LS 2025 was much higher than that of those prepared with LS 2032 and displayed excellent water and solvent resistance. Note that the coating layers of Examples 11a to 13a (Examples 37 to 42) gained hardness when the ratio of isophthalic acid to sebacic acid was increased. The same applies for the increase in OH functionality. Examples 49 to 68 Mixtures of the polyester resin dispersions with LS 2025 using 0.1 wt.% of Sn diorite as catalyst’ were diluted to spraying viscosity, sprayed over a water borne metallic base coat (Autowave® ex Akzo Nobel Coatings BV). and allowed to dry at 60=C for 30 minutes as well as at ambient temperature (RT). The NCOiOH ratio was 1.5. After one day the D.O.I, (distinction of image) and the gloss were measured in accordance with ASTM D-523 at 20° and 60°. A D.0.1. of between 60 and 80 is acceptable, whereas a gloss value on a base coat at 20° of above 80 is considered high, while a gloss value at 60° of above 90 is considered very high. The results are given in Table 3, Examples 69 to 74 The aqueous polyester resin dispersions (component A) were mixed with poly-functional isocyanate cross-linkers (component B) in a ratio NCO:OH = 1.5 using 0.1 wt.% of Sn dilaurate as catalyst. The aqueous coating composition was diluted with methoxy isopropyl acetate to obtain a volatile organic content of 250 g/l, For the isocyanate cross-linkers use was made of four polyisocyanates, all commercially available from Bayer: a) Desmodur LS 2025 (a hydrophobic isocyanurate based on 1,6-hexamethylene diisocyanate), b) Desmodur LS 2550 (a hydrophobic uretdione based on 1,6-hexamethylene diisocyanate), c) Bayhydur LS 2032 (a hydrophilic isocyanurate based on 1,6-hexamethylene diisocyanate, modified with about 12 wt.% of methoxy polyethylene oxide glycol), and d) Desmodur LS 2150 (a hydrophilic isocyanurate based on isophorone diisocyanate, modified with about 9 wt.% of methoxy polyethylene oxide glycol). The mixtures of polyester resin dispersions and the isocyanate components were applied on steel panels. The panels were allowed to dry at ambient (room) temperature (RT) for one week. The Persoz Hardness was determined in accordance with French industrial standard method NF T30-016, the result being expressed in seconds, and is given in Table 4. Examples 75 to 80 The aqueous polyester resin dispersions (component A) were mixed with poly-functional isocyanate cross-linkers (component B) in a ratio NCO:OH = 1.5 using 0.1 wt% of Sn dilaurate as catalyst. The aqueous coating composition was diluted with methoxy isopropyi acetate to obtain a VOC of 250 g/l. The aqueous coating compositions were sprayed over a water home metallic base coat (Autowave® ex Akzo Nobel Coatings BV) and allowed to dry at 60°C for 30 minutes. After one day the D.O.I, (distinction of Image) and the gloss were measured in accordance with ASTM D-523 at 20*" and 60°. The results are given in Table 5. Comparison Example I Example 1 was repeated, except that 597.6 g of sebacic acid were replaced by 431.9 g of adipic acid. The polyester resin had an add value of 15.2 mg KOH/g and a practical OH value of 150.0 mg KOH/g, Comparison Example la Example 1a was repeated, except that the flask was filled with 500 g of the polyester resin of Caparison Example 1, instead of 500 g of the polyester resin of Example 1, after which there ‘were added 9.6 g of N,N-dimethyl ethanol amine and 490,4 g of demineralised water. The polyester resin dispersion had the following properties: pH = 7.7, particle size (nm) = 72, wt % solids: 50,0 Comparison Example II Example 1 was repeated, except that 398.6 g of isophthaiic acid were replaced by 355.4 g of ophthalmic anhydride. The polyester resin had an acid value of 16.0 mg KOH/g and a practical OH value of 138 mg KOH/g. Comparison Example 11a Example la was repeated, except that the flask was filled with 500 g of tiie polyester resin of Comparison Example II, instead of 500 g of the polyester resin of Example 1. after which there were added 10.2 g of N, N- dimethyl ethanol amine and 415.7 g of demineralised water. The polyester resin dispersion had the following properties: pH = 7,8, particle size = 97 nm, wt.% solids; 54 The water home polyester resin dispersions of Example 1a, Comparison Example la. Comparison Example 11a, and Example 7b were submitted to a statiorts test in an oven at 35°C. The dispersions were about 3 weeks old at the start The results are given in Table 6. The polyester resin dispersions according to the invention (Examples 81 and 82) are good to use after one year of storage at SS'‘C and give about the same coatings properties as freshly prepared dispersions. The polyester resin dispersions prepared according to the Comparison Examples (A and B) are no longer useful after 6 months of storage at 35X. WE CLAIM: 1. A branched hydroxyl-functional polyester resin having an average hydroxyl functionality of > 2, a hydroxyl number of 25 to 300 mg KOH/g, and a number average molecular weight within the range of from 500 to 3,000, which polyester resin comprises polyalkylene oxide groups and, optionally, sulphonate groups, wherein the polyester resin has a carboxylic acid number of 2. The branched hydroxyl-functional polyester resin according to claim 1, wherein the tri- or higher-functional acid is selected from the group of trimellitic acid and pyromellitic acid or the anhydride thereof 3. The braced hydroxyl-functional polyester resin according to any one of the preceding claims, wherein the tri- or higher-functional polyalcohol is selected from the group of 1,1,1-trimethylol propane, 1,1,1-trimethylol ethane, 1,2,3-trimethylol propane, and pentaerythritol. 4. The branched hydroxy 1-functional polyester resin according to any one of the preceding claims, wherein the amount of C1-C4 alkoxy polyalkylene oxide groups in the polyester resin is in the range of 2.5 to 15 wt.%. 5. The branched hydroxyl-functional polyester resin according to claim 4, wherein the amount of C1-C4 alkoxy polyalkylene oxide groups in the polyester resin is in the range of 5 to 10 wt. %. 6. An aqueous dispersion of a branched hydroxyl-functional polyester resin according to any one of the preceding claims, characterised in that the concentration of polyester resin particles with an average particle size of 30 to 300 nm is 45 to 65 wt. % at a viscosity up to 5 Pa.s. 7. An aqueous cross-linkable binder composition comprising A) at least one branched hydroxyl-functional polyester resin according to any one of the preceding claims, and B) at least one organic hydrophobic polyisocyanate. 8. The aqueous cross-linkable binder composition according to claim 7, wherein the NCO:OH equivalent ratio, based on the isocyanate groups of component (B) and the hydroxyl groups of component (A), is within the range of from 0,5:1 to 3:1. 9. The aqueous cross-linkable binder composition according to any one of the claims 7 and 8, wherein the isocyanate groups of component (B) are free isocyanate groups. 10. The aqueous cross-linkable binder composition according to any one of preceding claims 7, 8, and 9, wherein said composition includes another type of polymer or polymer dispersion. 11. The aqueous cross-linkable binder composition according to any one of preceding claims 7, 8, 9, and 10, wherein said composition includes a reactive diluent. 12. A process for preparing a lacquer, coating or adhesive wherein the aqueous cross-linkable binder composition according to any one of preceding claims 7 to 11 is employed as binder. 13. An aqueous coating composition comprising the aqueous cross-linkable binder composition according to any one of preceding claims 7 to 11. 14. A process for remising a car wherein the aqueous coating composition according to claim 13 is applied.

Full Text

The invention relates to a branched hydroxyl-fictional polyester resin and an aqueous dispersion and a cross-linkable binder composition comprising the same. The resin has an average hydroxyl functionality of > 2, a hydroxyl number of 25 to 300 mg KOH/g, and a number average molecular weight within the range of from 500 to 3,000, which polyester resin comprises polyalkylene oxide groups and, optionally, sulphonate groups.
Polyester resins and their use in two-component aqueous-based coating compositions are known from, int. al., EP-A-0 537 568 and WO 94/28043. The water-dilatable. polyesters disclosed therein contain both sulphonate and hydroxyl groups. Though high-quality coating layers can be obtained with the known aqueous-based coating compositions, the solids content of the aqueous polyester dispersions used in the known compositions is too low to be competitive in a great many applications, such as coating compositions to be used in automotive refinishing shops. The concentration of the polyester particles in the examples of both prior art publications does not exceed 35 wt. %. Furthermore, the storage stability of the aqueous polyester dispersions is inferior. Moreover, in order to emulsify the hydrophobic polyisocyanates in EP-A-0 537 568, frequently use has to be made of an external emulsifier, whereas in the examples of WO 94/28043 always use is made of polyisocyanate modified with polyethylene oxide glycol.
A disadvantage of high water content is that the elimination of said water after the composition has been formed into, int. al, a coating layer requires a lot of time and energy. A further disadvantage of the known coating compositions is that the binder compositions exempHfied in WO 94/28043 are said to have a gel time of 3 to 6 hours, whereas on the other hand the curing speed of the binder compositions exemplified in WO 94/28043 is rather low (> 12 hrs at 50’C).

The invention now provides a branched hydroxyi-functionai polyester resin having an average hydroxyl functionality of > 2, a hydroxy! number of 25 to 300 mg KOH/g, and a number average molecular weight within the range of from 500 to 3,000, which polyester resin comprises polyalkylene oxide groups and, optionally, sulphonate groups, characterised in that the polyester resin comprises the reaction product of
1) a module of cartxDxydc acids comprising
50 to 80 mole% of an m- and/or p-aromatic and/or cycioaliphatic dicarboxyiic acid,
20 to 50 mole% of an aliphatic dicariDoxylic acid and/or aliphatic monocarboxylic acid with more than 6 carbon atoms, and, optionally, a tri- or higher-functional acid, and
2) a mixture of alcohols comprising
an aliphatic did with at least 4 carrion atoms and/or a cydoaliphatic diol with at least 4 carton atoms, a CrC4 alkoxy polyalkylene oxide glycol and/or CrC4 alkoxy polyalkylene oxide 1,3-diol having a number average molecular weight of 500 to 3,000, and, optionally, a tri- or higher-functional playschool, wherein the polyester resin has a carboxylic acid number of Also provided according to the invention is an aqueous dispersion comprising the branched hydroxyi-functionai polyester resin and an aqueous cross-linkable binder composition comprising the branched hydroxyi-functionai polyester resin and a organic hydrophobic polyisocyanate. Further provided according to the invention is the use of the aqueous cross-linkable binder composition in coating compositions, lacquer compositions, and adhesives. Finally, the present

invention provides the use of such aqueous coating compositions in car refinish applications.
The storage stability of the branched hydroxyl-functional polyester resin according to the invention is excellent Aqueous dispersions comprising the branched hydroxyl-functional polyester resin may have a solids content of more titan 45 Wl% at a viscosity of up to 5 Pa.s. The branched hydroxyl-functional polyester resin is able to disperse organic hydrophobic polyisocyanates in the absence of external emulsifiers. Aqueous cross-linkable binder compositions comprising a branched hydroxyl-functional polyester resin and an organic hydrophobic polyisocyanate have an acceptable pot life and cure speed. Aqueous coating compositions comprising the aqueous cross-linkable binder composition according to the present invention provide coatings having excellent properties like gloss, hardness, and distinctness of image (DOl).
The branched hydroxyl-functional polyester resin can be prepared using conventional polymerisation procedures known to be effective for polyester resin synthesis. The reacBon to form the polyester resin may be conducted in one or more stages. In order to obtain a branched polyester resin, the conder’ati'on reaction is carried out in the presence of a branching agent, which may be a tri- or higher-functional acid and/or alcohol. For tiie tri- or higher-functional acid preference is given to an add selected from the group of trimelfiHc acid and pyromellitic acid or the anhydride thereof- For the tri- or higher’unctional polyalcohol preference is given to a polyalcohol selected from tine group of 1,1,1-trimethylol propane, 1,1,1-trimethylol ethane, 1,2,3-tiimethylol propane, pentaeryOirrtol, and mixtures thereof. More preferred is the use of a prior higher-functional playschool. Most preferred is the use of 1,1,1-trimethylol propane.

If desired, the polyester resin may contain a proportion of carbonylamino linking groups -C(=0)-NH- (i.e. amide linking group) by including an appropriate amino-functional reactant as part of the "hydroxyl component" (such amide linkages are in fact useful in that Italy are more hydnDlysis-resistant and more hydrophilic.)
In order to achieve hydroxyl functionality in the resulting polyester resin, a stoichiometric excess of the hydroxyl component should be used. Furthermore, in order to achieve an average hydroxyl functionality of > 2, preferably 2.3, more preferably 2.5, the polyester resin must have a branched structure.
The mixture of carboxylic acids may comprise m-aromatic dicarboxylic acids, p-aromatic dicarboxylic acids, cycloaliphatic dicariDoxyiic acids, aliphatic dicariDoxylic acids with more than 6 carbon atoms, and aliphatic monocarboxyiic acid with more than 6 clarion atoms.
Suitable dicarboxylic acids for obtaining excellent hydrolytic stability as well as excellent mechanical properties are m-aromatic dicarboxylic acids such as isophthalic acid, p-aromatic dicarboxylic acids such as terephthalic acid and dimethyl terephthalate, and cycloaliphatic dicarboxylic acids such as 1,4-cydohexane dicarboxyiic acid and hexahydrophthaiic anhydride. Mixtures of these dicarboxylic acids may also be used.
Suitable aliphatic dicarboxylic acids with more than 6 carbon atoms include azelaic acid and sebacic acid. Suitable aliphatic monocarboxyiic acids with more than 6 carbon atoms include isononanoic acid, decanoic acid, 2-’thylhexyi cari’oxylic acid, and didecanoyl acid. Mixtures of these aliphatic dicarboxylic adds and/or aliphatic monocarboxyiic acids may also be used.

Furthermore, the mixture of carboxylic acids may contain a small amount of an alkali salt of a sulphonic acid-substituted mono- or dicarboxylic acid or ester. Preferably, an alkali salt of a sulphonic acid-substituted dicarboxyfic acid or ester is used, such as sodium suiphosuccinic acid and 5-(sodium sulpho) isophthalic acid.
The mixture of alcohols may comprise aliphatic diois with at least 4 carbon, atoms, cydoaliphatic diois with at least 4 carbon atoms, C1-C4 alkoxy potyalkyiene oxide glycols and/or C1-C4 alkoxy polyalkylene oxide 1,3-diols having a number average molecular weight of 500 to 3,000.
Suitable (cyclo)aliphatic diois for the preparation of the hydroxyl-functional polyester resin are diois having at least 4 carbon atoms such as 1,4-butane diol, 1,6-hexane diol, 2,2-dimethyl-1,3-propane diol, 2-ethyl-2-propyl-1,3-propane diol. 1,2-, 1,3-, and 1,4-cyclohexane diois, the corresponding cyclohexane dimethanol, and mixtures thereof.
In order to incorporate a hydrophobic organic polyisocyanate into the aqueous polyester resin dispersion without the use of external emulsifiers, tie polyester resin should comprise a C1-C4 alkoxy polyalkylene oxide group. The preferred alkylene oxide groups are ethylene oxide groups, but alternatively propylene oxide groups or mixtures of ethylene oxide and propylene oxide groups are useful as well. For example, the alkylene oxide groups may be C1-C4 alkoxy ethers of polyalkylene glycols witty the structure:

wherein R1 is a hydrocarbon radical with 1 to 4, preferably 1 or 2, carbon atoms; R2 is a metiiyl group; x is between 0 and 40, preferably between 0 and 20, most preferably between 0 and 10; y is between 0 and 50, and x+y is between 2 and 50, preferably between 2 and 25. The distribution of the alkylene glycols may be at random, alternating distribution or blocked. Examples are Ci-C4 alkoxy polyC2{C3)alkylene oxide glycol and/or CrC4 alkoxy polyC2{C3)aIkylene oxide 1,3-diol, wherein polyC2(C3)alkylene oxide stands for polyethylene oxc, optionally comprising propylene oxide units. Preferably the polyester resin comprises 2.5 to 15 wt.% C1-C4 alkoxy pofyalkyiene oxide groups with a number average molecular weight of 500 to 3,000, preferably between 500 and 1,500, most preferably between 500 and 1,250, while preference is given to a polyester resin comprising 5 to 10 wt.% of CI-CA alkoxy polyalkylene oxide groups. Optimum result are obtained with a polyester resin wherein the polyalkylene oxide units are polyethylene oxide units.
Suitable CrC4 alkoxy polyalkylene oxide compounds contain at least one hydroxyl group. Examples are methoxy polyC2(C3)alkylene oxide glycols and methoxy polyC2(C3)alkylene oxide"1,3-diols, such as Tegomer® D-3123 (PO/EO = 15/85; Mn = 1,180). Tegomer® D-3409 (PO/EO = 0/100; Mn = 2,240), and Tegomer® D-3403 (PO/EO = 0/100; Mn = 1,180) available from Goldschmidt AG, Germany, and MPEG 750 and MPEG 1000.
Optionally, aminoalcohol may be used in the preparation of the polyester resin. Examples of mono-alcohois include n-hexanol, 2-ethyl hexanol, cyclohexanol, tell butyl cyclohexanol. stearyl alcohol, dodecagon, and mobsters thereon.
The polyester resin has a carboxylic add number of
number of The polyester resin has a hydroxyl number of 25 to 300 mg KOH/g. preferably 50 to 250 mg KOH/g, more preferably 100 to 220 mg KOH/g. The polyester resin has a number average molecular weight within the range of from 500 to 3,000, preferably 750 to 2,500, more preferably 1,000 to 2,000.
At the end of the polycondensation reaction the carboxylic acid groups of the polyester resin are at least partially neutralized with a neutralising agent, after which water is added, preferably to the hot melt at a temperature starting at 100 to 110’0, after which the temperature is gradually lowered to ambient temperature.
The aqueous polyester resin dispersion obtained in this manner may have a solids content of more than 45 wL%, preferably 45 to 65 wL%, more preferably 50 to 60 wL%, at a viscosity of up to 5 Pa.s, preferably 0.1 to 3 Pa-S. The average particle size of the thus obtained dispersion is in the range of 30 to 300 nm, and preferably in the range of 50 to 200 nm. The thus obtained dispersion has a pH between 6 and 9, preferably between 6.5 and 8.

Examples of neutralising agents include alkali metal hydroxides, such as sodium hydroxide, potassium hydroxide, or lithium hydroxide, ammonia, and amines. Suitable amines include primary, secondary, and tertiary amines. Suitable primary amines are, for example, isopropyl amine, butyl amine, ethanol amine, 3-amino-1-propanol, 1-amino-2-propanol, 2-amino-2-methyl"1-propanol or 2-amino-2-methyH,3-propane diol Secondary amines that can be used are, for example, morpholine, diethyl amine, dibuty! amine, N-methy ethanol amine, dietitian amine, or dfisopropanol amine. Examples of suitable tertiary amines include trimethyl amine, triethyl amine, triisopropyl amine, triisopropanol amine, N,N-dimethyl ethanol amine, dimethyl isopropyl amine, N,N-diethyl ethanol amine, 1-dime1tiyl amino-2-propanol, 3-dimethyl amino-1-propanol, 2-dimethyl amino-2-methyH-propanol, N-methyl dimethanol amine, N-methyl dimethanol amine, N-butyl dimethanol amine, N-ethyl morpholine. Tertiary amines are preferred. More preen-ed is N,N-dimethyl ethanol amine.
The invention relates also to an aqueous cross-linkable binder composition comprising
A) at least one branched hydroxyl-functional polyester resin and
B) at least one organic hydrophobic polyisocyanate.
The organic hydrophobic polyisocyanate (component B) includes polyfunctional, preferably free polyisocyanates with an average NCO functionality of more than 2, preferably 2.5 to 5, and may be (cyclo)aliphatic, araliphatic or aromatic in nature. Preferably, the hydrophobic organic polyisocyanate has a viscosity at 22’*0 of 0.1 to 5 Pa.s. Examples of hydrophobic organic polyisocyanates include
1,6-diisocyanatohexane, isophorone diisocyanate, 2,4-toIuene diisocyanate. 2,6-toiuene diisocyanate, diphenyl methane-diisocyanate, 4,4'-bis(isocyanato-cyclohexyl) methane, 1,4-diisocyanatobutane, 1,5-diisocyanato-2,2-dimethyl pentane, 2,2,4-trimethy!-1,6-diisocyanatohexane, 1,10-dilsocyanatodecane, 4,4-diisocyanato-cyciohexane, 2,4-h6xahydrotoluene disocyanate, 2,6-

hexahydrotoluene diisocyanate, norbomane diisocyanate, 1.3-xylylene diisocyanate, 1,4-xyfylene diisocyanate, 1-isocyanato-3-(isocyanato methyl)-1-methyl cyclohexane, m-a,a-a' ,a'-tetrame11iyl xylylene diisocyanate, and mixtures thereof. The hydrophobic polyisocyanate may include beret, refinance, uretdione, and isocyanurate derivatives of the above-mentioned compounds. Normally, these products are liquid at ambient temperature and commercially available in a wide range. Particularity preferred isocyanate curing agents are diisocyanates and adducts. Examples thereof are 1,8-diisocyanato-4-(isocyanatomethyl) octane, the adduct of 3 moles of toluene diisocyanate to 1 mole of trimethylol propane, the isocyanurate trimmer of 1,6-diisocyanatohexane, the isocyanurate trimer of isophorone diisocyanate, the uretdione dimer of 1,6-diisocyanatohexane, the biuret trimer of 1,6-diisocyanatohexane, the adduct of 3 moles of m-a,a-a\a'-tetramethylc xylene diisocyanate to 1 mole of trimethylol propane, and mixtures thereof. More preferred are the isocyanurate and redbones of 1,6-hexane diisocyanate and isophorone diisocyanate. Usually these compounds contain small quantities of their higher homologues.
Optionally, the aqueous cross-linkable binder composition may also comprise an organic hydrophilic polyisocyanate compound substituted with non-ionic groups, such as the above-mentioned C1-C4 alkoxy polyalkylene oxide groups. Preferably, 30 wt.% of non-ionic groups may be present on total solid polyisocyanate corporal, i.e. organic hydrophobic and hydrophilic polyisocyanate, more preferably 20 wt%, most preferred 15 wL%, Preferred are the isocyanurate of 1,6-hexane diisocyanate and isophorone diisocyanate substituted within methoxy polyetiiylene glycol.
The polyisocyanate and the aqueous polyester resin dispersion should be mixed in such a ratio that the NCO;OH ratio is in the range of 0.5-3:1, preferably 0.75-2.5:1, and more preferably 1-2:1.

The organic hydrophobic polyisocyanate compound B) and, optionally, the organic hydrophilic polyisocyanate may be mixed into component A) by any suitable technique. However, simply stirring is usually sufficient Sometimes It may be useful to dilute the polyisocyanate somewhat with an organic solvent like butyl acetate or 1-meftoxy-2-propyl acetate to reduce the viscosity of the polyisocyanate.
The binder composition may contain catalysts like amines and Sn-based catalysts, such as dibutyl tin dilaurate and dibutyl tin acetate. The pot life at ambient temperature usually is between 4 and 12 hours, depending on the use of the catalysts and their amount
The coating compositions may further comprise other ingredients, additives or auxiliaries, such as other polymers or polymer dispersions, pigments, dyes, emulsifiers (surfactants), pigment dispersion aids, wetting agents, levelling agents, anti-catering agents, antifoaming agents, ant sagging agents, heat stabilisers, UV absorbers, antioxidants, and fillers.
Suitable types of other polymer dispersions include acrylic polymer emulsions and aqueous polyurethane dispersions.
Also included in the binder .or coating compositions of the invention may be reactive diluents such as water-soluble mono- or (preferably) polyhydric alcohols. Examples of monohydric alcohols include hexyl glycol, butoxyelhanol, 1-’ethoxy-propanol-2, 1-ettioxy-propanol-2, .1-propoxy-propanol-2, 1-butoxy-propanol"2, 2-methoxybutanol, 1-isobutoxy-propanoI-2, dipropylene glycol monomethyl ether, diacetone alcohol, methanol, ethanol, propanol. isopropanol, butanol, 2-butanol, pentanol, hexanol, benzyl alcohol, and mixtures thereof. Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, propylene glycol, isomeric butane diols, the polyethylene oxide glycols or

polypropylene oxide glycols, 1,1,1 -trimethylol propane, 1,2,3-trimethylol propane, pentaerythritol, glycerol, and mixtures thereof.
The composition of the present invention consists essentially of water, being an
aqueous composition. However, about 20 wt.% of liquid content of the
composition may be an organic solvent. As suitable organic solvents may be
mentioned dimethyl dipropylene glycol, methyl ether of diacetone alcohol, ethyl
acetate, butyl acetate, ethyl glycol acetate, butyl glycol acetate, l-methoxy-2-
propyl acetate, butyl propionate, ethoxy ethyl propionate, toluene, xylene;
methyl ethyl ketone, methyl isobutyl ketone, methyl Amy! ketone, ethyl amyl
ketone, dioxolane, N-methyl-2-pyrrolidone, dimethyl carbonate, propylene carbonate, butyrolactone, caprolactone, and mixtures thereof. The volatile organic content of
the composition may range from 0 to 400 g/l, preferably from 0 to 250 g/l.
The coating composition of the present invention may be applied to any substrate. The substrate may_ be, for example, metal, plastic, wood, glass, ceramic, or some other coating layer. The other coating layer may be comprised of the coating composition of the current invention or it may be a different coating composition. The coating compositions of the current invention show particular utility as clear coats, base coats, pigmented top coats, primers, and fillers. The coating compositions can be applied by conventional means such as by spray gun, brush, or roller, spraying being preferred. Curing temperatures preferably are between 0 and 80°C and more preferably between 10 and 60°C. The compositions are particularly suitable in the preparation of coated metal substrates, such as in the refinish industry, in particular the body shop, to repair automobiles and transportation vehicles, and in finishing large transportation vehicles such as trains, trucks, buses, and aero planes.
Preferred is the use of the coating composition of the present invention as a clear coat. Clear coats are required to be highly transparent and must adhere

well to the base coat layer. It is further required that the clear coat does not change the aesthetic aspect of the base coat by strike-in, i.e. discolourations of the base coat due to its solvation by the clear coat composition, or by yellowing of the clear coat upon outdoor exposure. A clear coat based on the coating composition of the present invention does not have these drawbacks.
In the case of the coating composition being a clear coat tiie base coat may be a conventional base coat known in the coating art Examples are solvent bome base coats, e.g., Autobase® ex Akzo Nobel Coatings BV, based on cellulose acetobutyrate and acrylic resins, and water bome base coats, e.g., Autowave®
0
ex Akzo Nobel Coatings BV, based on an acrylic.resin dispersion. Furthermore, the base coat may comprise pigments (colour pigments, metallics and/or pearls), wax, solvents, flow additives, neutralising agent, and defoamers. Also high solids base coats can be used. These are, for instance, based on polyols, imines, and isocyanates. The clear coat composition is applied to the surface of a base'coat and then cured. An intermediate curing step for the base coat may be introduced,.
The invention will be illustrated with reference to the following examples. Of course these examples are submitted for a better understanding of the invention only; they are not to be construed as limiting in any manner the scope thereof.

Examples
In the following examples, the preparation of a number of water borne polyester resin dispersions and binder compositions according to the invention is disclosed. The properties measured on these dispersions are listed in Table 1. The dispersions' average particle size given in to table was detemnined with the aid of dynamic fight scattering, with tiie dispersions diluted to a solids content of about 0.1 wL%. The viscosity was determined with a Brookfield viscometer (LV - 4; 60 revolutions per minute). The solids content was determined in accordance with ASTM motion no. 1644-59, within heating to MO'‘C over a period of 30 minutes. The Mn was measured with GPC with polystyrene as standard.
Preparation of branched water borne polyester resin dispersions
Example 1: Preparation of the branched polyester resin
A 3 I flask fitted with a stirrer, a thermometer, a reflux condenser, and a nitrogen
inlet was charged with a mixture composed of:
597.6 g of sebacic acid
398.4 g of isophthalic acid
426.2 g of 1,4-cyclohexane dimethyl ol
314.5 g of 2,2-dimethyl-1,3-propane diol
246.5 g of 1,1,1-trimethylol propane
0.25 g of Fascist 41 GO (Sn-based catalyst) After deaeration, the flask was brought under a nitrogen atmosphere. The contents of the flask were heated to 150°C, whereupon tiie temperature was gradually increased to 200°C over a period of 2 hours. The temperature of 200°C was maintained in the flask until a clear reaction melt was obtained. After the collection of 171 ml water of distillation, a clear reaction mixture was

obtained. The mixture was cooled to 140*’0, after which the following
components were added:
172.6 g of isophthalic acid and
180 g of methoxy polyethylene oxide glycol (Mn = 750).
The reaction McClure was gradually heated to 210°C and kept at this
temperature until an acid value of 14.9 mg KOH/g was obtained.
The practical OH-value was 139.0 mg KOH/g, the OH-functionality was 3.0, and
= 1,376.
Example la: Preparation of a dispersion from the branched polyester resin of
Example 1
A 2 1 flask fitted within a stirrer, a thermometer, a reflux condenser, and a
dropping funnel was filled with 500 g of tiie polyester resin of Example 1.
The contents of the flask were heated to 110°C, at which temperature tiers
were added:
9.5 g of N,N-dimethyl ethanol amine (con'esponding to a neutralizations degree
(N.R.) of the carboxylic groups of 80%) and subsequently, over a period of 3
hours: 433.9 g of Demineralised water, after which the temperature was
gradually decreased from 100°C to 30°C.
The properties of the thus obtained water borne polyester resin dispersion are
given in Table 1.
Example lb: Preparation of a dispersion from the branched polyester resin of
Example 1
In a manner analogous to that disclosed in Example la, a dispersion was
prepared, with the proviso that this time the following ingredients were added to
tine flask containing 500 g of tiie polyester resin of Example 1:
8.9 g of N,N-dimethyl eternal amine and 383.9 g of demineralized water.
The properties of the thus obtained water borne polyester resin dispersion are
given in Table 1.

Example 2
In a manner analogous to that disclosed in Example 1, a polyester resin was
prepared, with the proviso that this time the flask was charged with:
597.6 g of sebacic acid
398.4 g of isophthalic acid
426.2 g of 1,4-cyclohexane dimethyl ol
253.2 gof2,2-dimethyl-1.3-pnDpanediol
321.5 g of 1,1,1-trimethyloi propane
0.25gofFascat4100
After a dear reaction mixture had been obtained, there were added:
185.9 g of isophthalic acid and
180 g of methoxy polyethylene oxide glycol (Mn = 750).
The end product had an acid number of 13.0 mg KOH/g, a practical OH-value of
147, an OH-functionality of 3.25, and a Mn of 1,487.
Example 2a
Example 1 a was repeated, with the proviso that the flask was charged with:
500 g of the polyester resin of Example 2, after which there were added 8.3 g of
N,N-demurely ethanol amine and 472.1 g of Demineralised water.
The properties of fire thus obtained water borne polyester resin dispersion are
given in Table 1.
Example 2b
In a manner analogous to that disclosed in Example 2a, a dispersion was
prepared, with the proviso that this time the following ingredients were added to
the flask containing 500 g of polyester resin of Example 2:
7.25 g of N,N-dimethyl ethanol amine and 370 g of Demineralised water.
The properties of the thus obtained water borne polyester resin dispersion are
given in Table 1.

Example 3
In a manner analogous to that disclosed in Example 1, a polyester resin was prepared, with the proviso that this time the flask was charged with: 409.0 g of sebacic acid 237.0 g of isononanoic add 503.0 g of tsophthanc add 399.6 g of 1,4-cydohexane trimethylol 82.0 g of 2,2-dimethyl-1,3-propane diois 496.5 g of 1,1,14rimethyfo( propane
0.25 g of Fascist 4100 After a clear reaction mixture had been obtained, there were added: 161.8 g of isophthalic acid and
191.3 g of methoxy polyethylene oxide glycol (Mn = 750). The end product had an acid number of 14.0 mg KOH/g, a practical OH-value of 136, an OH-functionality of 3, and a Mn of 1,370,
Example 3a
Example la was repeated, with the proviso that the flask was charged with:
500 g of the polyester resin.of Example 3, after which there were added 8.35 g
of N,N-dimethyl ethanol amine and 462.5 g of Demineralised water.
The properties of the tries obtained water borne polyester resin dispersion are
given in Table 1.
Example 3b
In a manner analogous to that disclosed in Example 3a, a dispersion was
prepared, with Vr\e proviso that \h\s time the following ingredients were added to
c
the flask containing 500 g of the polyester resin of Example 3:
7.2 g of N,N-dimethyl ethanol amine and 377.8 g of demineralised water.
The properties of IMe thus obtained water borne polyester resin dispersion are
given in Table 1.

Example 4
In a manner analogous to that disclosed in Example 1, a polyester resin was
prepared, within the proviso fiat this time the flask was charged with:
348.5 g of sebacic acid
237.0 g of isononarxDJc acid
552.8 g of isophthalic acid
399.6 g of 1,4-cydohexane trimethylol
82.0 gof2,2-dimethyl-1,3-propanediol
496.5 g of 1,1.1-trimethylol propane
0.25gafFascat4100
After a clear reaction mixture had been obtained, there were added: 161.8 g of isophthalic acid and
191.3 of methoxy polyethylene oxide glycol (Mn = 750).
The end product had an acid number of 13.5 mg KOH/g, a practical OH-value of 136, an OH-functionality of 3, and a Mn of 1,381.
Example 4a
Example 1a was repeated, with the proviso that the flask was charged with:
500 g of the polyester resin of Example 4, after which there were added 6.45 g
of N,N-dimethyl ethanol amine and 370.7 g of demineralised water.
The properties of the thus obtained water home polyester resin dispersion are
given in Table 1.
Example 5
In a manner analogous to that disclosed in Example 1, a polyester resin was
prepared, with the proviso that this time the flask was charged with:
597.6 g of sebacic add
398.4 g of isophthalic acid
569.1 9 of 2,2-dimethyl-1,3"propane did
321.6 g of 1,1,1-trimethylol propane

0.25 g of Fascat4100 After a clear reaction mixture had been obtained, there were added: 199.2 g of Isophtiiaiic acid and
168 g of methoxy polyethylene oxide glycol (Mn = 750). The end product had an acid number of 14.6 mg KOH/g, a practical OH-value of 151, an OH-functionarrty of 3.5, and a Mn of 1,443.
Example 5a
Example 1a was repeated, with the proviso that the flask was charged with:
500 g of the polyester resin of Example 5, after which there were added 8.1 g of
N,N-dimethyl ethanol amine and 417.8 g of demineralised water.
The properties of the thus obtained water bome polyester resin dispersion are
given in Table 1.
Example 6
In a manner analogous to that disclosed in Example 1, a polyester resin was
prepared, with the proviso that this time the flask was charged with:
348.4 g of sebacic acid
237.0 g of isononanoic acid
550.4 g of isophthalic acid
376.7 g of 2,2-dimethyl-1,3-propane diol
504.5 g of 1,1,1 "trimethylol propane
0.25gofFascat4100
After a dear reaction mixture had been obtained, there were added:
186.7 g of isophthalic acid and
180 g of methoxy polyethylene oxide glycol (Mn = 750).
The end product had an acid number of 13.3 mg KOH/g, a practical OH-value of
135, an OH-functionality of 3.5, and a Mn of 1,352.

Example 6a
Example 1a was repeated, with the proviso that the flask was charged with:
500 g of the polyester resin of Example 6, after which there were added 6.9 g of
N,N”dimethyl ethanol amine and 402.2 g of demineralised water.
Tithe properties of the thus obtained water bome polyester resin dispersion are
given in Table 1.
Example 7
In a manner analogous to that disclosed.in Example 1, a polyester resin was prepared, with the proviso that this time the flask was charged with: 21.4 g of 5-{sodium siphon) isophtiialic acid 192.6 g of isophthalic acid 426.2 g of 1.4-cyclohexane dimethyl
253.4 g of2,2-dimethyi-1,3-propanediol
321.6 g of 1,1,1-trimethylol propane
25.0 g of demineralised water
0,25gof Fascat4100 The homogenised mixture was gradually heated to 180°C and kept at this temperature until a clear mixture had been obtained. After 62 ml water of distillation had been collected, the clear reaction mixture was cooled to 140°C. At this temperature tiers were added: 597.9 g of sebacic acid and
192.5 g of isophthalic add.
After tiie temperature of tiie reaction mixture had been gradually increased to 195°C, the mixture was kept at this temperature until 201 ml water of distillation had been collected and a clear reaction melt obtained. After the reaction mixture had been cooled to 140’*0, the following components were added;
172.6 g of isophthalic acid and
180.0 g of methoxyl polyethylene oxide glycol (Mn = 750).

The reaction mixture was gradually heated to 215°C and kept at said temperature until an acid value of 6.7 mg KOH/g was obtained. The practical OH-value was 144. the OH-functionality was 3.25, and the molecular weight Mn = 1,593,
Example 7a
Example la was repeated, with the proviso tilt the flask was charged with:
500 g of the polyester resin of Example 7, after which Tiered were added 3.2 g of
N,N-dimethyl ethanol amine and 496.8 g of demineralised water.
The properties of the thus obtained water borne polyester resin dispersion are
given in Table 1.
Example 7b
Example 7a was repeated, except that this time:
1.6 g of N,N-dimethyl ethanol amine and 424.3 g of demineralised water were
added.
The properties of the obtained polyester resin dispersion are given In Table 1.
Example 8
In a manner analogous to that disclosed in Example 7, a polyester resin was prepared, with proviso that this time the flask was charged with: 194.2 g of isophthalic acid 16.1 g of 5-{sodium sulpho) isophthalic acid
579.1 g of 2,2-dimethyl-1,3-propane diol
321.6 g of 1,1,1 -trimethyiol propane
20.0 g of demineralised water
0.25gofFascat4100 After a clear reaction mobsters had been obtained, there were added:
194.2 g of isophthalic acid and
597.9 g of sebacic acid.

After this reaction mixture became clear, the following components were added:
185.9 g of isophthalic acid and
168-0 g of methoxy polyethylene oxide glycol (Mn = 750).
The end product had an acid number of 8,4 mg KOH/g, a practical OH-value of
150 mg KOH/g, an OH-functionality of 3.5, and a Mn of 1,875.
Example 8a
Example la was repeated, with the proviso that the flask was chained wilt:
500 g of the polyester resin of Example 8, after which there were added 2.7 g of
N,N-dimethyl ethanol amine and 497.3 g of demineralised water.
The properties of the thus obtained water borne polyester resin dispersion are
given in Table 1.
Example 9
In a manner analogous to that disclosed in Example 7, a polyester resin was prepared, with the proviso that this time the flask was charged with: 269.9 g of isophthalic acid 17.1 g of 5-{sodium sulpho) isophthalic acid
376.7 gof2,2"dimethy!-1.3-propanediol
504.5 g of 1,1,1-trimethylol propane
25.0 g of demineralised water 0.25gof Fascat4100 /Meter a dear reaction mixture had been obtained, there were added:
269.8 g of isophtinallc acid
348.4 g of sebacic acid
237.0 g of isononanoic acid.
After this reaction obscure became clear, the following components were added:
174.3 g of isophthalic acid and
180.0 g of methoxy polyethylene oxide glycol (Mn = 750).

The end product had an acid number of 6.7 mg KOH/g, a practical OH-value of 134 mg KOH/g, an OH-functionality of 3.25, and a Mn of 1,548.
Example 9a
Example 1a was repeated, wifely the proviso that the flask was charged with:
500 g of the polyester resin of Example 9, after which there were added 2.13 g
of N.N-dimethyl ethanol amine and 459.4 g of demineralised water.
The properties of the thus obtained water bome polyester resin dispersion are
given in Table 1.
Example 10
In a manner analogous to that disclosed in Example 7, a polyester resin was
prepared, with the proviso that this time the flask was charged with:
219.1 g of isophthalic acid
21,4 g of 5-(sodium sulpho) isophtiialic acid
426.2 g of 1,4-cyciohexane dimethylol
253.4 g of 2,2-dimethyl-1,3-propane diol
321.6 g of 1,1.1-trimethylol propane
25.0 g of demineralised water 0.25 g of Fascist 4100 After a clear reaction mixture had been obtained, there were added: 219.1 g of isophthalic acid and
533.3 g of sebacic acid.
After friars reacBon mixture became clear, the following components were added:
172,6 g of isc’hthalic acid and
1 BO.O g of methoxy polyethylene oxide glycol (Mn = 750).
The end product had an acid number of 6.5 mg KOH/g, a practical OH-value of
145 mg KOH/g, an OH-functionality of 3.25, and a Mn of 1,817.

Example 10a
Example 1a was repeated, with the proviso that the flask was charged with:
500 g of the polyester resin of Example 10, after which there were added 1.55 g
of N,N-dime1hyl eternal amine and 478.8 g of demineralised water.
The properties of the thus obtained water borne polyester resin dispersion are
given in Table 1.
Example 11
In a manner analogous to that disclosed in Example 7, a polyester resin was
prepared, with the proviso that this time a 2 1 flask was charged with:
145.7 g of isophthalic acid
13.0 g of 5-(sodium siphon) isophthalic acid 266.4 g of 1.4-cycIohexane dimethylol 152.3 g of 2,2-dimethyl-1,3-propanediol 201.0 g of 1,1,1 "trimethylol propane
35.0 g of demineralised water 0.70gof Fascat4100 After a clear reaction mixture had been obtained, there were added: 145.7 g of isophthalic acid and 266.3 g of sebacic add.
After this reaction mature became clear, the following components were added: 145.7 g of isophthalic add and
111.0 g of methoxy polyethylene oxide glycol (Mn = 1,000). The end product had an add number of 8,0 mg KOH/g, a practical OH-value of 146 mg KOH/g, an OH-functionality of 3.5, and a Mn of 1,773.
Example 11a
Example 1a was repeated, with the proviso that a 1 1 flask was charged with: 250 g of ttie polyester resin of Example 11, after which there were added 1.0 g of N,N-dimethyl ethanol amine and 196.4 g of demineralised water.

The properties of the thus obtained water borne polyester resin dispersion are given in Table 1.
Example 12
In a manner analogous to that disclosed in Example 7, a polyester resin was
prepared, within the proviso that this time a 21 flask was charged with:
160.3 g of isophfrialic add
13.0 g of 5-{sodium sulpho) isophthafic acid
266.4 g of 1,4-cydohexane dimethylol
152,3 g of 2,2-dimethyH,3’ropane diol
201.0 g of 1,1.1-trimethylol propane
35.0 g of demineralised water 0.70gof Fascat4100 After a clear reaction mixture had been obtained, there were added: 160.3 g of isophthalic add and 212.9 g of sebacic dd.
After this reaction mixture became clear, the following components were added: 160.3 g of isophthalic add and
109.0 g of methoxy polyethylene oxide glycol (Mn = 1,000), The end product had an acid number of 8.0 mg KOH/g, a practical OH-value of 147 mg KOH/g, an OH-functionality of 3.5, and a Mn of 1,767
Example 12a
Example la was repeated, with the proviso that a 11 flask was charged with:
250 g of the polyester resin of Example 12, after which there were added 1.0 g
of N,N-dimethyl ethanol amine and 196.4 g of demineralised water.
The properties of the thus obtained water borne polyester resin dispersion are
given in Table 1.

Example 13
In a manner analogous to that disclosed in Example 7, a polyester resin was
prepared, with the proviso that this time a 2 1 flask was charged with:
171.0 g of isophthalic acid
13.0 g of 5-(sodium sulpho) isophthalic acid 266.4 g of 1,4-cydc’exane dimethylol 150.8 gof2,2-dimethyi-1,3-propanediol 201.0 g of 1,1,1 -trimethylol propane
35.0 g of demineransed water 0.70 g of Fascist 4100 After a clear reaction brute had been obtained, there were added: 169.6 g of isophthalic acid and 177.6 g of sebacic acid.
After a clear reaction mixture had been obtained, there were added: 169.6 g of isophthalic acid and
109.0 g of methoxy polyethylene oxide glycol (Mn = 1,000).
The end product had an acid number of 5,1 mg KOH/g, a practical OH-value of 144 mg KOH/g, an OH-functionality of, and a Mn of 1908.
Example 13a
Example la was repeated, with the proviso that a 11 flask was charged with:
250 g of the polyester resin of Example 13. after which there were added 0.6 g
of N,N-dimethyl ethanol amine and 250 g of demineralised water.
The properties of the thus obtained water bome polyester resin dispersion are
given in Table 1.
Example 14
in a manner analogous to that disclosed in Example 7, a polyester resin was
prepared, with the proviso that this time a 6 I flask was charged with:
385.1 g of isophthalic add

42,9 g of 5-(sodium siphon) isophthalic acid 852,5 g of 1,4-cyclohexane dimethylol 1265 g of 1.1.1 "trimethyiol propane
50.0 g of deminerailsed water O.SOgof Fascat4100 After a clear reaction mixture had been obtained, there were added:
385.1 g of isophthafic acid and 1195.8 9 of sebacic acid. After fries reaction McClure became clear, the following components were added:
345.3 9 of isophfriafic acid and
360.0 g of methoxy polyethylene oxide glycol (Mn = 750).
The end product had an acid number of 6.4 mg KOH/g, a practical OH-value of
199 mg KOH/g, an OH-functionality of 4.9, and a Mn of 1,771
Example 14a
Example 1 a was repeated, with the proviso that the 21 flask was charged with:
500 g of the polyester resin of Example 14, after which there were added 1.5 g
of N,N-dimethyl eternal amine and 425.9 g of demineralised water.
The properness of the. thus obtained water borne polyester resin dispersion are
given in Table 1.
Example 15
In a manner analogous to that disclosed in Example 7, a polyester resin was prepared, with the proviso that this time a 2 I flask was charged with: 145.7 g of isophthalic acid 13,4 9 of 5-{sodium sulpha) isophthalic acid
266.4 g of 1,4-cydohexane dimethylol
395.3 g of 1,1,1-trimethyiol propane
35.0 g of demineralised water 0,70 g of Fascist 4100

After a clear reaction mixture had been obtained, there were added: 145.7 g of isophthaiic acid and
266.3 g of sebacicacid.
After this mixture became clear, the following components were added:
145.7 g of isophthaiic acid and
114.0 g of metfioxy polyethylene oxide glycol (Mn = 1,000).
The end product had an acid number of 6.4 mg KOH/g, a practical OH-value of
200 mg KOH/g, an OH-unisonant of 5.1, and a Mn of 1,801,
Example 15a
Example 1a was repeated, with the proviso that the flask was charged with:
250 g of the polyester resin of Example 15, after which there were added 0.8 g
of N,N-dimethyl ethanol amine and 221.7 g of deminerailsed water.
The properties of the thus obtained water borne polyester resin dispersion are
given in Table 1.
Example 16
In a manner analogous to that disclosed in Example 7, a polyester resin was prepared, with the proviso that this time the 2 I flask was charged with: 171.0 g of isophthaiic acid 13.4 g of 5-(sodium sulpho) isophthaiic acid
266.4 g of 1,4-cydohexane dimethylol
395.3 g of 1,1,1-trimethylol pupae
35.0 g of deminerailsed water 0.70gof Fascat4100 After a clear reaction mixture had been obtained, there were added:
169.5 g of isophthaiic acid and
177.6 g of sebacicacid.
After this reaction mixture became clear, the components were added: 169.6 g of isophthaiic acid and

112.5 g of methoxy polyethylene oxide glycol (Mn = 1,000). The end product had an acid number of 7.9 mg KOH/g, a practical OH-value of 204 mg KOH/g, an OH-fundfonallty of 5.1, and a Mn of 1,893.
Example ISa
Example 1a was repeated, with the proviso that the flask was charged with:
250 g of the polyester resin of Example 16, after which there were added 0.9 g
of N.N-dimethyl ‘howl amine and 270.8 g of demlrrerallsed water.
The properties of the obtained polyester resin dispersion are given in Table
1 and la.

Examples 17 to 48
The aqueous polyester resin dispersions (component A) were mixed with poly-functional isocyanate cross-linkers (component B) in a ratio NCO:OH = 1.5. The polyester resin dispersions were diluted with butyl glycol (10 wt.% on solids). The isocyanate components were diluted with methoxy isopropyl acetate (80 wL% on solids).
For the isocyanate cross-linkers use was made of two potyisocyanates, both commercially available from Bayer
a) Desmodur LS 2025 (a hydrophobic isocyanurate based on 1,6-
hexamethyiene ditsocyanate). and
b) Bayhydur LS 2032 (a hydrophiiic isocyanurate based on 1,6-hexamethylene
diisocyanate, modified with about 12 wt.% of methoxy polyethylene oxide
glycol).
No use was made of a catalyst.
The mixtures with LS 2025 according to the invention all had a solids content of
more than 50 wt.%, whereas the mixtures with the hydrophiiic LS 2032
(comparison) had a maximum achievable solids content of between 40 and 45
wt%.
The mixtures of polyester resin dispersions and the isocyanate components
were applied on glass panels in a dry layer thickness between 60 and 80 p.m-
The panels were allowed to dry at ambient (room) temperature (RT) for one
week.
The Pesos Hardness was determined in accordance with French industrial
standard method NF T30-O16, the result being expressed in seconds, and is
given in Table 2.
The hardness of the coating layers prepared with LS 2025 was much higher
than that of those prepared with LS 2032 and displayed excellent water and
solvent resistance.

Note that the coating layers of Examples 11a to 13a (Examples 37 to 42) gained hardness when the ratio of isophthalic acid to sebacic acid was increased. The same applies for the increase in OH functionality.

Examples 49 to 68
Mixtures of the polyester resin dispersions with LS 2025 using 0.1 wt.% of Sn diorite as catalyst’ were diluted to spraying viscosity, sprayed over a water borne metallic base coat (Autowave® ex Akzo Nobel Coatings BV). and allowed to dry at 60=*C for 30 minutes as well as at ambient temperature (RT). The NCOiOH ratio was 1.5.
After one day the D.O.I, (distinction of image) and the gloss were measured in accordance with ASTM D-523 at 20° and 60°. A D.0.1. of between 60 and 80 is acceptable, whereas a gloss value on a base coat at 20° of above 80 is considered high, while a gloss value at 60° of above 90 is considered very high. The results are given in Table 3,

Examples 69 to 74
The aqueous polyester resin dispersions (component A) were mixed with poly-functional isocyanate cross-linkers (component B) in a ratio NCO:OH = 1.5 using 0.1 wt.% of Sn dilaurate as catalyst. The aqueous coating composition was diluted with methoxy isopropyl acetate to obtain a volatile organic content of 250 g/l, For the isocyanate cross-linkers use was made of four polyisocyanates, all commercially available from Bayer:
a) Desmodur LS 2025 (a hydrophobic isocyanurate based on 1,6-hexamethylene diisocyanate),
b) Desmodur LS 2550 (a hydrophobic uretdione based on 1,6-hexamethylene diisocyanate),
c) Bayhydur LS 2032 (a hydrophilic isocyanurate based on 1,6-hexamethylene diisocyanate, modified with about 12 wt.% of methoxy polyethylene oxide glycol), and
d) Desmodur LS 2150 (a hydrophilic isocyanurate based on isophorone diisocyanate, modified with about 9 wt.% of methoxy polyethylene oxide glycol).
The mixtures of polyester resin dispersions and the isocyanate components were applied on steel panels. The panels were allowed to dry at ambient (room) temperature (RT) for one week. The Persoz Hardness was determined in accordance with French industrial standard method NF T30-016, the result being expressed in seconds, and is given in Table 4.

Examples 75 to 80
The aqueous polyester resin dispersions (component A) were mixed with poly-functional isocyanate cross-linkers (component B) in a ratio NCO:OH = 1.5 using 0.1 wt% of Sn dilaurate as catalyst. The aqueous coating composition was diluted with methoxy isopropyi acetate to obtain a VOC of 250 g/l.
The aqueous coating compositions were sprayed over a water home metallic base coat (Autowave® ex Akzo Nobel Coatings BV) and allowed to dry at 60°C for 30 minutes. After one day the D.O.I, (distinction of Image) and the gloss were measured in accordance with ASTM D-523 at 20*" and 60°. The results are given in Table 5.

Comparison Example I Example 1 was repeated, except that 597.6 g of sebacic acid were replaced by 431.9 g of adipic acid.
The polyester resin had an add value of 15.2 mg KOH/g and a practical OH value of 150.0 mg KOH/g,
Comparison Example la Example 1a was repeated, except that the flask was filled with 500 g of the polyester resin of Caparison Example 1, instead of 500 g of the polyester resin of Example 1, after which there ‘were added 9.6 g of N,N-dimethyl ethanol amine and 490,4 g of demineralised water. The polyester resin dispersion had the following properties: pH = 7.7, particle size (nm) = 72, wt % solids: 50,0
Comparison Example II Example 1 was repeated, except that 398.6 g of isophthaiic acid were replaced by 355.4 g of ophthalmic anhydride.
The polyester resin had an acid value of 16.0 mg KOH/g and a practical OH value of 138 mg KOH/g.
Comparison Example 11a Example la was repeated, except that the flask was filled with 500 g of tiie polyester resin of Comparison Example II, instead of 500 g of the polyester resin of Example 1. after which there were added 10.2 g of N, N- dimethyl ethanol amine and 415.7 g of demineralised water. The polyester resin dispersion had the following properties: pH = 7,8, particle size = 97 nm, wt.% solids; 54
The water home polyester resin dispersions of Example 1a, Comparison Example la. Comparison Example 11a, and Example 7b were submitted to a statiorts test in an oven at 35°C. The dispersions were about 3 weeks old at the start The results are given in Table 6.

The polyester resin dispersions according to the invention (Examples 81 and 82) are good to use after one year of storage at SS'‘C and give about the same coatings properties as freshly prepared dispersions. The polyester resin dispersions prepared according to the Comparison Examples (A and B) are no longer useful after 6 months of storage at 35X.

WE CLAIM:
1. A branched hydroxyl-functional polyester resin having an average hydroxyl
functionality of > 2, a hydroxyl number of 25 to 300 mg KOH/g, and a number average molecular weight within the range of from 500 to 3,000, which polyester resin comprises polyalkylene oxide groups and, optionally, sulphonate groups, wherein the polyester resin has a carboxylic acid number of 2. The branched hydroxyl-functional polyester resin according to claim 1, wherein the tri- or higher-functional acid is selected from the group of trimellitic acid and pyromellitic acid or the anhydride thereof
3. The braced hydroxyl-functional polyester resin according to any one of the preceding claims, wherein the tri- or higher-functional polyalcohol is selected from the group of 1,1,1-trimethylol propane, 1,1,1-trimethylol ethane, 1,2,3-trimethylol propane, and pentaerythritol.

4. The branched hydroxy 1-functional polyester resin according to any one of the preceding claims, wherein the amount of C1-C4 alkoxy polyalkylene oxide groups in the polyester resin is in the range of 2.5 to 15 wt.%.
5. The branched hydroxyl-functional polyester resin according to claim 4, wherein the amount of C1-C4 alkoxy polyalkylene oxide groups in the polyester resin is in the range of 5 to 10 wt. %.
6. An aqueous dispersion of a branched hydroxyl-functional polyester resin according to any one of the preceding claims, characterised in that the concentration of polyester resin particles with an average particle size of 30 to 300 nm is 45 to 65 wt. % at a viscosity up to 5 Pa.s.
7. An aqueous cross-linkable binder composition comprising

A) at least one branched hydroxyl-functional polyester resin according to any one of the preceding claims, and
B) at least one organic hydrophobic polyisocyanate.

8. The aqueous cross-linkable binder composition according to claim 7, wherein the NCO:OH equivalent ratio, based on the isocyanate groups of component (B) and the hydroxyl groups of component (A), is within the range of from 0,5:1 to 3:1.
9. The aqueous cross-linkable binder composition according to any one of the claims 7 and 8, wherein the isocyanate groups of component (B) are free isocyanate groups.

10. The aqueous cross-linkable binder composition according to any one of preceding
claims 7, 8, and 9, wherein said composition includes another type of polymer or
polymer dispersion.
11. The aqueous cross-linkable binder composition according to any one of preceding claims 7, 8, 9, and 10, wherein said composition includes a reactive diluent.
12. A process for preparing a lacquer, coating or adhesive wherein the aqueous cross-linkable binder composition according to any one of preceding claims 7 to 11 is employed as binder.
13. An aqueous coating composition comprising the aqueous cross-linkable binder composition according to any one of preceding claims 7 to 11.
14. A process for remising a car wherein the aqueous coating composition according
to claim 13 is applied.

Documents:

« Previous Patent

Next Patent »

Patent Number

209509

Indian Patent Application Number

IN/PCT/2002/1711/CHE

PG Journal Number

50/2007

Publication Date

14-Dec-2007

Grant Date

04-Sep-2007

Date of Filing

18-Oct-2002

Name of Patentee

AKZO NOBEL N.V

Applicant Address

Velperweg 76 NL-6824 AB Arnhem

Inventors:

#	Inventor's Name	Inventor's Address
1	BUTER, Roelof	Surinkhof 1 NL-6952 HT Dieren

PCT International Classification Number

C08G 18/08

PCT International Application Number

PCT/EP2001/004316

PCT International Filing date

2001-04-13

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	00201423.1	2000-04-20	EUROPEAN UNION