AU654600B2

AU654600B2 - Water-dilutable, urethane-modified and hydroxyl group-containing self-crosslinking binder and formulations thereof

Info

Publication number: AU654600B2
Application number: AU30211/92A
Authority: AU
Inventors: Reiner Exner; Udo Frank; Heinz-Peter Klein; Michael Schwaab; Gerd Walz
Original assignee: Hoechst AG
Current assignee: Hoechst AG
Priority date: 1991-12-21
Filing date: 1992-12-17
Publication date: 1994-11-10
Anticipated expiration: 2012-12-17
Also published as: JP3293914B2; EP0548727B1; NO302034B1; CZ371892A3; NO924923L; ZA929812B; MX9207460A; EP0548727A2; DE4142734A1; JPH05247170A; ES2114546T3; AU3021192A; NO924923D0; BR9205063A; EP0548727A3; DE59209262D1; CA2084737A1; ATE164604T1

Abstract

A water-dilutable, urethane-modified and hydroxyl-containing binder prepared by reacting a polyester containing hydroxyl groups and neutralised and/or neutralisable acid groups with substoichiometric amounts (based on the number of free hydroxyl groups) of a partially blocked polyisocyanate. This binder is suitable for the production of paint films and other coatings of this type.

Description

COM

F/U(JIO1 1 28FWe Regulation 3.2(2)

AUSTRALIA

Patents Act 1990

ORIGINAL

PLETE SPECIFICATION TANDARD PATENT WATER-DILUTABLE, URETHAN E-MODIFIED AND HYDROXYL GROUP-CONTAINING SELF.-CROSSLINKING BINDER AND FORMULATIONS THEREOF

S

Application Number: Lncted: Invention Title: The following best method of statement Is a full description of this Invention, Including the performing It known to :-US Irr..- r 1 91/F 397 Water-dilutable, urethane-modified and hydroxyl groupcontaining self-crosslinking binder and formulations thereof The present invention relates to novel, urethane resinmodified, hydroxyl group-containing binders, which are dispersed and/or dissolved in a (predominantly) aqueous medium, and the use thereof, preferably as stoving coating compositions for the production of coating films and coatings.

Conventional stoving systems are frequently based on the combination of a binder with a corresponding crosslinking component. Incompatibilities between these components can .arise. An additional factor in the case of aqueous systems is that the crosslinking component as a rule also has to be compatible with water or is stabilized in the aqueous phase by the emulsifier action of the binder.

d In the present invention the incompatibility between crosslinking agents (polyisocyanates in the invention) and binders (polyester-polyol containing anionic groups in the invention) is prevented by partial covalent bonding of the isocyanate components to the polyester resin, so that a self-crosslinking one-component stoving system is obtained.

The storage stability of the binder of the present invention, which is predominantly dispersed in water, is consequently considerably greater than that of a combination of the polyester-polyol with the correspondingly completely capped polyisocyanate. In detail, the subject of the invention is a water-dilutable, urethane-modified and hydroxyl group-containing binder which is prepared by reacting a polyester containing free hydroxyl groups and neutralized and/or neutralizable acid groups with substoichiometric amounts (with respect to the number of 2 free hydroxyl groups) of a partially blocked polyisocyanate. The binder according to the invention preferably contains hydroxyl groups of 3-350, in particular 5-170 milliequivalents OH/100 g of binder solid resin.

The proportion of capped isocyanate groups (expressed as NCO) is preferably between 0.5 and 10% by weight, with respect to solid resin, and that of the urethane groups is preferably between 0.5 and 20% by weight, with respect to solid resin (expressed as In order to obtain the dilutability with water, the resin contains neutralizable and/or neutralized acid groups, generally carboxylic acid, sulfonic acid or phosphonic acid groups.

The content of these groups is customarily between 5 and 200, preferably between 10 and 90 milliequivalents of sulfonate and/or carboxylate and/or phosphonate in 100 g of binder solid resin.

'The polyester-polyols used as starting material are prepared by conventional processes by a condensation reaction of polycarboxylic acids, polyalcohols and i 20 hydroxy carboxylic acids, all of which can optionally contain further carboxylic acid sulfonic acid or phosphonic acid groups.

The polycarboxylic acids can be of aliphatic, cycloaliphatic, aromatic and/or heterocyclic type and can optionally be substituted, for example, by halogen atoms.

Examples whic nay be mentioned of such carboxylic acids and their ,vatives are: succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, S'"terephthalic acid, sulfoterephthalic acid, sulfoisophthalic acid, sulfophthalic acid, isophthalic acid, trimellitic acid, pyromellitic acid, tetrahydrophthalic •acid, hexahydrophthalic acid, di- and tetrachlorophthalic acid, endomethylenetetrahydrophthalic acid and its hexachloro derivative, glutaric acid, maleic acid, fumaric acid and fatty acid dimers and trimers. In place of these acids it is also possible to use their anhydrides, insofar as these exist. F3 The polyalcohuls used are preferably low-molecular polyols, polyhydroxy-polyethers, polylactone-polyols and polycarbonate-polyols. Suitable low-molecular polyols are, for example, ethanediol, the various propanediols, butanediols and hexanediols, dimethylolcyclohexane, 2, 2-bis (4-hydroxycyclohexyl )propane, diethylene glycol, triethylene glycol, glycerol, trimethylolethane or trimethylolpropane, hexanetriol, pentaerythritol, dipenterythritol or sorbitol; in addition, low-molecular polyols, preferably diols, which also contain an ionic group in the form of the carboxylic acid, sulfonic acid or phosphonic acid group are also used. These acid groups can be free and/or present in salt form. Examples of this group of monomers are a-C 2 -Cl-bishydroxy carboxylic acids, such as, for example, dihydroxypropionic acid, dimethylolpropionic acid, dihydroxyethylpropionic acid, dimethylolbutyric acid, tartaric acid, dihydroxymaleic 'acid, dihydroxybenzoic acid or 3-hydroxy-2-hydroxymethylpropanesulfonic acid and dihydroxybutanesulfonic acids.

Suitable polyhydroxy-polyethers are compounds of the formula H O OH in which R is hydrogen or a lower alkyl radical, optionally carrying diverse substituents, n is a number from 2 to 6 and m is a number from 10 to 120.

Examples are poly(oxytetramethylene)glycols, poly- (oxyethylene)glycols and poly(oxypropylene)glycols. The preferred polyhydroxy-polyethers are poly(oxypropylene)glycols having a molecular weight in the range from 400 to 5,000.

The polylactone-polyols derived from lactones are obtained, for example, by reaction an E-caprolactone with a polyol. Products of this type are described in

II

I

4 US Patent 3,169,945.

The polylactone-polyols, which are obtained by this reaction, are characterized by the presence of a terminal hydroxyl group and by recurring polyester fractions which are derived from the lactone. These recurring molecule fractions can have the formula 0 C (CHR)n CH20 in which n is preferably 4 to 6 and the substituent R is hydrogen, an alkyl radical, a cycloalkyl radical or an alkoxy radical, no substituent containing more than 12 carbon atoms.

'The lactone used as starting material can be any lactone or any combination of lactones and this lactone should contain at least 6 carbon atoms in the ring, for example 6 to 8 carbon atoms, and 2 hydrogen substituents chould be present on the carbon atom which is bonded to the Soxygen group of the ring. The lactone used as starting 20 material can be represented by the following general formula:

CH

2

CR

2 )n-C=0 0 0 in which n and R have the meaning already indicated.

The lactones preferred in the case of the invention are 25 e-caprolactones, in which n has the value 4. The most preferred lactone is unsubstituted 6-caprolactone, in which n has the value 4 and all R substituents are hydrogen. This lactone is particularly preferred since it is available in large amounts and gives coatings which have excellent properties. In addition, various other lactones can be used on their own or in combination.

WINWNM

ii 5 Examples of aliphatic polyols suitable for tbh reaction with the lactone are ethylene glycol, 1,3-propanediol, 1,4-butanediol, hexane-l,6-diol, dimethylolcyclohexane, trimethylolpropane and pentaerythritol.

The polycarbonate-polyols or polycarbonate-diols are compounds which have the general formula 0 HO-R-( O-C-0-R-)n-OH in which R is an alkylene radical. These OH-functional polycarbonates can be prepared by reacting polyols, such as propane-, 3-diol, butane-l,4-diol, hexane-1,6-diol, diethylene glycol, triethylene glycol, 1,4-bishydroxymethylcyclohexane, 2,2-bis(4-hydroxycyclohexyl)propane, 'neopentyl glycol, trimethylolpropane or pentaerythritol, with dicarbonates, such as dimethyl carbonate, diethyl o* carbonate or diphenyl carbonate, or phosgene. Mixtures of such polyols can also be used.

The following may be mentioned as preferred examples of hydroxy carboxylic acids: salicylic acid, sulfosalicylic acid and salts thereof.

The polyester-polyols are prepared by known methods in a multistage process depending on the rate of esterification of the carboxylic acids. For the preferred case of 25 the preparation of a polyester-polyol from a mixture of aromatic and aliphatic dicarboxylic acids, the aromatic carboxylic acids are first esterified with the hydroxyfunctional components in the presence of a catalyst and the aliphatic carboxyl group-containing reactants are then introduced, since, as is known, the rate of esterification of aromatic carboxylic acids, such as, for example, isophthalic acid, is considerably slower than that of dimethylolpropionic acid and the latter, in turn, is slower than, for example, that of adipic acid.

c- ~--ccpa _q~ r 6 In the case of the polyestch-noyols containing sulfonic acid groups it can be necessary, in order to achieve as quantitative as possible a condensation reaction of the sulfo monomer, to carry out the synthesis also in a multistage process. To this end, the entire hydroxylfunctional components are first reacted with the sulfo monomers and optionally with the aromatic, carboxylic acid-containing components in the presence of catalysts, so that 95% of the amount of distillate calculated for a quantitative conversion is obtained from the condensation reaction. The aliphatic car)oxylic acid components are then reacted, where appropriate, the condensation reaction being carried out until a free acid group content of less than 18 meq (COOH)/100 g is obtained.

The polycondensation reaction takes place at temperatures between 150 and 230"C, preferably between 160 and 210°C.

Suitable catalysts are, preferably, organometallic compounds, in particular zinc-, tin- or titanium-containing compounds, such as, for example, zinc acetate, dibutyltin 20 oxide or tetrabutyl titanate. The amount of catalyst is S.preferably 0.1 to 1.5% by weight of the total batch.

The polyester-polyols obtained in this way are then reacted with a partially capped polyisocyanate. Suitable polyisocyanates are all compounds of this type known here, for example trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, propylene diisocyanate, ethylene diisocyanate, 2,3-dimethylene diisocyanate, 1-methyl-trimethylene diisocyanate, 1,3-cyclopentylene 30 diisocyanate, 1,4-cyclohexylene diisocyanate, 1,2-cyclohexylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phonylene diisocyanate, 2,4-toluylene diisocyanate, 2,6-toluylene diisocyanate, 4,4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,4-naphthalene diisocyanate, 1,3,3,3-trimethylcyclohexane, bis(4-isocyanatocyclohexyl)methane, bis(4-isocyanatocyclophenyl)methane, L ~I: 7 4,4'-diisocyanatodiphenyl ether, 2,3-bis(8-isocyanatotrimethylxylylene diisocyanate or tetramethylxylylene diisocyanate or mixtures of these compounds.

In addition to these simple polyisocyanates, those which contain hetero-atoms in the radical linked to the isocyanate groups are also suitable. Examples of such compounds are polyisot' ates which contain carbodiimide groups, allophonate groups, isocyanurate groups, urethane groups, acylated urea groups or biuret groups.

Suitable polyisocyanates are, finally, also those higher functional isocyanates which are prepared by reacting a diisocyanate with a polyol (for example trimethylolpropane or pentaerythritol), as well as the ethoxylated 'and/or propoxylated derivatives thereof having a degree of alkoxylation of 0.5 to 4.5 ethylene oxide and/or propylene oxide per hydroxyl functional group.

Suitable capping agents are aliphatic, cycloaliphatic or alkyl-aromatic (monohydric) alcohols, for example lower S 20 aliphatic alcohols, such as methyl alcohol or ethyl alcohol, the varicus propyl, butyl and hexyl alcohols, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol and the like, and also unsaturated alcohols such as propargyl alcohol or allyl alcohols, cycloaliphatic alcohols, sv "h as cyclopentanol or cyclohexanol, alkylaromatic alcohols, suci as benzyl alcohol, p-methylbenzyl alcohol, p-methoxybenzyl alcohol and p-nitrobenzyl alcohol, and monoethers of glycols, such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether 30 and the like. Further capping agents are phenols, ketoximes, expediently having 3 to 20 carbon atoms, preferably 3 to 10 carbon atoms, such as acetone oxime, methyl ethyl ketone oxime butanone oxime), hexanone oxime (such as methyl butyl ketone oxime), heptanone oxime (such as methyl n-amyl ketone oxime), octanone oxime and cyclohexanone oxime, CH-acid compounds, such as _r .LgCL_, _I

I--

1111 8 malonic acid alkyl esters, acetoacetates and also cyanoacetates, in each case having 1 to 4 carbon atoms in the ester group, NH-acid compounds, such as caprolactam and amino alcohols, such as diethylethanolamine.

The polyisocyanates are reacted in accordance with methods known per se with an amount of a capping agent such that the ratio of free isocyanate groups to capped isocyanate groups is 1:4 to 1:0.5.

These partially capped polyisocyanates are then reacted in accordance with known methods with the polyesterpolyol described above, specifically in proportions by weight such that. the end product has the parameters defined initially. Any free acid groups present are then finally completely or partially neutralized. Aqueous solutions of alkali metal hydroxides or amines, for example trimethylamine, triethylamine, dimethylaniline, diethylaniline, triphenylamine, dimethylethanolamine, aminomethylpropanol, dimethylisopropanolamine or ammonia, are used for this purpose.

If the relative reactivities of the polyester-polyol and the capping agent with respect to the polyisocyanate permit, there are also the following two process possibilities: the polyisocyanate is added to the capping agent, which has' been initially introduced with the Spolyester-polyol, if appropriate in the presence of a catalyst, and, in the case of appropriate selectivity, the claimed binder can also be obtained in .tt.i this way.

the polyester-polyol is reacted with the polyisocyanate, if appropriate in the presence of a catalyst, until only the required free OH equivalents are still present. The capping agent is then added to thid NCO-functional polymer and in this way it is possible to block the isocyanate groups in order to obtain the claimed binder.

The aqueous dispersions of the binders according to the invention can be used to prepare coating systems, as binders for water-dilutable adhesives or as resins for printing inks.

In the case of appropriate compatibility, they can also optionally be combined with other aqueous plastic dispersions and/or solutions, for example acrylic polymers and/or methacrylic polymers, polyurethane, polyurea resins, polyester resins and epoxy resins, thermoplastics based on polyvinyl acetate, polyvinyl chloride, polyvinyl ether, polychloroprene or polyacrylonitrile and ethylenebutadiene-styrene copolymers.

'The binders according to the invention can be applied to very diverse substrates, for example ceramics, wood, glass, concrete and preferably plastics, such as polycarbonate, polystyrene, polyvinyl chloride, polyester, poly(meth)acrylates, acrylonitrile-butadienestyrene polymers and the like, as well as also preferably metals and alloys, such as iron, copper, aluminum, steel, tin, zinc, titanium, magnesium, brass, bronze and the like.

The binders according to the invention are suitable, for example, for the production of coating films, coatings and/or intermediate coatings for very diverse fields of application. After adding conventional coating additives, such as flow auxiliaries, wetting auxiliaries and dispersing auxiliaries, as well as conventional pigment 30 formulations (TiO 2 BaS04), they are suitable, in particular, as aqueous stoving filler coatings, which especially in the automobile industry are applied as intermediate coating between primer and top coat, stoving or forced drying being carried out at temperatures of to 200"C, in particular of 100 to 180"C, under otherwise customary stoving conditions. Compared with aqueous filler coatings used on the market, they are distinguished by very good protection against flying stones, very good resistance to warm and humid conditions and very good optical properties (gloss, surface structure).

Although it is not absolutely essential to add a crosslinking component when formulating water-dilutable coating compositions containing the binders according to the invention, it is nevertheless possible to add further crosslinking agents customary in coating technology, such as, for example, water-soluble or water-emulsifiable melamine or benzoguanamine resins, water--emulsifiable polyisocyanates or water-emulsifiable prepolymers containing terminal isocyanate groups, water-soluble or water-dispersible polyaziridines and blocked polyiso- ,cyanates, provided these are compatible.

Because of the high gloss, a good top coat quality can also be achieved using the binders according to the invention if suitable pigments are chosen. A prerequisite i a ii then, however, the use of non-yellowing polyisocyanates (for example aliphatic isocyanates). Short-term weathering tests show very good results.

A particular advantage of the binders according to the invention is their storage stability (Table 3).

1. Polyesters The preparation of the polyester-polyols is carried out under a N 2 atmosphere in a 4 1 four-necked round-bottomed flask provided with an anchor stirrer, a N 2 inlet, a temperature sensor and a packed column (about 20 cm long and 3 cm in diameter) fitted with a top thermometer and a descending condenser.

Polyester 1 1,241 g of hexanediol 365 g of neopentyl glycol

_I~

11 (NPG), 440 g of trimethylolpropane (TMP), 312 g of sulfoisophthalic acid dimethyl ester sodium salt and 3 g of anhydrous zinc acetate are subjected to a condensation reaction at 170 0 C to 220 0

C

and a maximum top temperature of 65 C until 50 g of distillate are obtained. The reaction mixture is cooled to 140 0 C, 445 g of terephthalic acid (TPA), 891 g of isophthalic acid (IPA) and 2.6 g of dibutyltin oxide (DBTO) are added and the condensation reaction is carried out at 200 0 C until a carboxyl group content of 26 meq (COOH)/100 g is obtained. The reaction mixture is cooled to 140"C, 706 g of adipic acid (ADPA) are added and the condensation reaction is carried out at temperatures of 165 to 220"C (maximum top temperature 100 0 C) until the carboxyl group content is 7 meq (COOH)/100 g.

1

.I

4 4 4 4 Polyester 2 665 g of hexanediol, 195 g of neopentyl glycol and 235 g of trimethylolpropane are melted, 210 g of terephthalic acid and 1.2 g of DBTO are then added at 100 0 C and the condensation reaction is carried out at 220'C and a maximum top temperature of 100°C until a clear melt is obtained. The reaction mixture is cooled to 160°C, 455 g of isophthalic acid and a further 1.2 g of DBTO are added and the condensation reaction is carried out until a 25 carboxyl group content of 35 meq (COOH)/100 g is obtained. The reaction is then cooled to 130°C and 910 g of adipic acid and 505 g of dimethylolpropionic acid (DMPA) are added and the condensation reaction is carried out at 1600C to 200 0 C (maximum top temperature 100°C) until a value of 90 meq (COOH)/100 g is obtained.

Polyester 3 500 g of hexanediol, 520 g of neopentyl glycol and 235 g of trimethylolpropane are melted and 300 g of terephthalic acid, 450 g of isophthalic acid and 2.5 g of DBTO are then added at 1000C. The condensation reaction is carried out at 190"C to 200 0 C until a carboxyl group content of 14 meq (COOH)/100 g is obtained, the reaction 12 mixture is cooled to 140 0 C, 900 g of adipic acid are added and the condensation reaction is carried out at 190 0 C to 200 0 C until a value of 133 meq (COOH)/100 g is obtained. The reaction mixture is then cooled to 140°C, 300 g of dimethylolpropionic acid are added and the condensation reaction is carried out at 170 0 C to 180°C (maxi;mum top temperature 100"C) until the carboxyl group content is 100 meq (COOH)/100 g.

Polyester 4 500 g of hexanediol, 400 g of neopentyl glycol and 350 g of trimethylolpropane are melted. 300 g of terephthalic acid, 450 g of isophthalic acid and 2.5 g of DBTO are added at 100 0 C and the condensation reaction is carried out at 190 0 C to 200°C until the carboxyl group content is 7 meq (COOH)/100 g. The reaction mixture is cooled to 140°C, 900 g of adipic acid and 300 g of dimethylolpropionic acid are added and the condensation reaction is carried out at 160 to 170 0 C until the free carboxyl group content is 128 meq (COOH)/100 g. The reaction mixture is then cooled to 140"C and a vacuum of 100 mbar is applied until a value of 110 meq (COOH)/100 g is reached (about min).

2. Self-crosslinking urethane-modified binders

(SUB)

The synthesis of the binders according to the invention is carried out in a 2 1 four-necked round-bottomed flask fitted with a reflux condenser and a temperature sensor.

SUB 1 75.0 g of diphenylmethane 4,4'-diisocyanate (MDI) are 30 added in the course of 7 min to 43.2 g of diethyl malonate, 0.8 g of sodium methylate and 74.0 g of methyl ethyl ketone and the mixture is stirred at 45 C, with cooling, until a NCO content of 5.5% is obtained. A solution of 269.5 g of polyester 1 in 92.5 g of methyl ethyl ketone is then added in the course of 2 min, the temperature is raised to 50 0 C and the reaction mixture is 13 .414 stirred until the NCO content is After further dilution with 54.4 g of butyl glycol/isopropanol (weight ratio the mixture is dispersed with 675 g of demineralized water heated to 50°C. 170 g of methyl ethyl ketone are distilled off from the aqueous phase under 250 mbar and at 60 0

C.

SUB 2 66.6 g of isophorone diisocyanate (IPDI) are'metered, in the course of 2 min, into 27.5 g of methyl ethyl ketoxime (MEK oxime), 0.4 g of dibutyltin dilaurate (DBTDL) and 55.6 g of methyl ethyl ketone and the mixture is stirred at 35"C, with cooling, until a NCO content of 8.5% is obtained. A solution of 294 g of polyester 2 in 110 g of methyl ethyl ketone is then added in the course of 3 min, the temperature is raised to 50"C and the reaction .mixture is stirred until the NCO content is After further dilution with 54.4 g of butyl glycol/isopropanol (weight ratio the mixture is neutralized with 20,0 g of triethylamine (TEA) and then dispersed with 675 g of demineralized water heated to 600. 170 g of methyl ethyl ketone are distilled off from the aqueous phase under 200 mbar and at 60 0

C.

SUB 3 435 g of methyl ethyl ketoxime are added to 1,110 g of isophorone diisocyanate and 0.75 g of DBTDL at 25 0 C to 30 0 C, with cooling, over a period of 75 min, the temperature is then raised to 40°C and the reaction mixture is stirred for a further 1 h. Isophorone diisocyanate capped on one side by methyl ethyl ketoxime is thus obtained.

30 55 g of n-methylpyrrolidone, 237.6 g of polyester 3 and 186.9 g of isophorone diisocyanate capped on one side, as described above, are stirred at 60"C until a NCO content of 0.4% is obtained. 21.1 g of dimethylethanolamine (DMEA) are then added and the reaction mixture is stirred for a further one hour at 60"C and dispersed with 715 g of demineralized water heated to

I

*l 1r -14- SUB 4 42.0 g of n-methylpyrrolidone, 220.0 g of polyester 4 and 92.0 g of isophorone diisocyanate capped on one side with content of 0.1% is obtained. 21.6 g of dimethylethanolamine are then added and the reaction mixture is stirred for a further one hour at 60"C and dispersed with 460 g of demineralized water heated to 60 0

C.

SUB 435 g of methyl ethyl ketoxime are added to 1,220 g of tetramethylxylylene diisocyanate (TMXDI) and 0.75 g of DBTL at 25"C to 30 0 C, with cooling, over a period of min, the temperature is then raised to 40°C and the reaction mixture is stirred for a further 1 h. TMXDI capped on one side with methyl ethyl ketoxime is obtained ,in this way.

45.0 g of n-methylpyrrolidone, 219.6 g of polyester 4 and j' 102.2 g of trimethylxylylene diisocyanate capped on one side with methyl ethyl ketoxime are stirred at 60°C until a NCO content of 0.1% is obtained. 36.2 g of triethanol- Samine (TOLA) are then added and the reaction mixture is stirred for a further one hour at 60 0 C and dispersed with 400g of demineralized water heated to 60 0

C.

SUB 6 230.0 g of polyester 4, 44.0 g of N-methylpyrrolidone, 27.4 g of methyl ethyl ketoxime and 0.05 g of dibutyltin dilaurate are stirred homogeneously at 35-40 0 C and 69.8 g of isophorone diisocyanate are metered in at such a rate .that the temperature does not rise above 65 0 C. The reaction mixture is stirred at 65"C until a NCO content of 0.10% is obtained. 22.6 g of dimethylethanolamine are then added at 65 0 C and the reaction mixture is stirred for a further hour and dispersed with 490 g of demineralized water heated to 65 0

C.

p, t P- -i I_i~ i Fga~ 15 Comparison example: 119.0 g of methyl ethyl ketoxime-capped isophorone diisocyanate (reaction of 1 mol of isophorone diisocyanate with 2 mol of methyl ethyl ketoxime in the presence of 0.15 g of dibutyltin dilaurate) are stirred homogeneously with 42.0 g of .N-methylpyrrolidone and 220.0 g of polyester 4 at 60 0 C and 21.6 g of dimethylethanolamine are added at this temperature. The reaction mixture is stirred for a further hour at 60 0 C and dispersed with 515.0 g of demineralized water heated to 0

C.

3. Example of a stoving filler coating composition based on SUB 4 (colour shade light gray) SUB 4 Wetting and dispersing auxiliaries ('Additol XL 250) Flow agent ('Additol XW 390) Titanium dioxide S 20 Blanc fixe micro Talc, Naintsch E 7 Flame soot 101 Deionized water Parts by weight 65.7 0.3 0.4 12.0 10.0 0.1 100.0 Test results: see Table 4 4( I I i, 16 4. Example of a water-dilutable top coating composition based on SUB li SUB 5 Wetting and dispersing auxiliaries ('Additol XL 250) Flow agent ('Additol XW 390) 25% in H 2 0 Light stabilizers ('Sanduvor 3212) in butyl glycol Titanium dioxide Deionized water Parts by weight 68.6 0.2 1.7 23.5 100.0 Test results fo:r SUB 5 in the too coat Test 20' .30°C 20' 150°C I t Coating thickness in [im 31 31 Gloss 200 76% 60° 88% 89% Pendulum hardness in sec 153 144 Cross-hatch on sheet steel C-H 0 C-H 0 Erichsen deep drawing on sheet steel in mm 9.9 9.9 Resistance to solvents acetone 20 sec 20 sec xylene 1 min 1 min ethanol/water 9 min 15 min *6 1'* 17 Test in total process (cathodic electrocoat/filler/top coat) [Cross-hatch IC-HO01 Erichsen deep drawing in mm 6 4! **Ste* *i~ j JL s a Table 1: Polyester-polyols Components Polyester 1 Polyester 2 Polyester 3 Polyester 4 sample mol mol sample mol mol sample mol mol sample mol mol weight (g) weight (g) weight (g) weight (g)

IPA

891 5,361 13.0 455 2,739 11.8 450 2,709 11.3 450 2,709 11.5

TPA

445 2,680 6.5 210 1,264 5.4 300 1,806 7.6 300 1,806 7.7

ADPA

706 4,831 11.7 910 6,227 26.8 900 6,158 25.8 900 6,158 26.1 DMPA DME-Na 312 1,053 2.5 505 3,765 16.2 300 2,237 9.4 300 2,237 9.5

HD

1,241 10,501 25.5 665 5,627 24.2 500 4,231 17.7 500 4,231 17.9

NPG

365 3,505 32.8 195 1,872 8.1 520 4,993 20.9 400 3,841 16.3

TMP

440 3,279 235 1,751 235 1,751 7.3 350 2,608 11.0 OH/COOH ratio meq (COOH)/100 g meq (OH)/100 g Polyester 1: 1.359 7 223 and 27 meq (S03-Na )/100 g Polyester 2: 1.147 90 204 Polyester 3: 1.195 100 252 Polyester 4: 1.206 110 273 The abbreviations are explained in th-e methods ;7sP;-~LVI I, r I L- rll~----sr 11:: 1 Table 2: Self-crosslinking, urethane-modified binders Polyester Isocyanate Capping Neutralizing meq acid meq OH used component agent agent (degree group/ group/ of neutra- 100 g 100 g lization, SUB 1 Polyester 1 MDI diethyl Na salt -SO :19 77 malonate SUB 2 Polyester 2 IPDI MEK oxime TEA -C00:53 60 (100%) SUB 3 Polyester 3 IPDI MEK oxime DMEA -COO:56 13 (100%) SUB 4 Polyester 4 IPDI MEK oxime DMEA -COO:78 96 (100%) SUB 5 Polyester 4 TMXDI MEK oxime TOLA -C00:75 93 (100%) SUB 6 Polyester 4 IPDI MEK oxime DMEA -COO:78 96 (100%) Comparison Polyester 4 IPDI MEK oxime DMEA -C00:72 177 Completely capped (100%) with respect to solid resin (neutralizing amine and auxiliary solvents are The abbreviations are explained in the methods urethane capped NCO [expressed as [expressed as -NCO]*) 4.56 3.24 4.5 3.24 7.65 5.94 5.68 4.04 5.50 3.92 5.68 4.04 7.44 of completely capped IPDI not calculated in the solid resin) re 1. I a. ~jL C. Table 3: Storge, stabilities SUB 1 SUB 2 SUB 3 SUB 4 SUB 5 SUB 6 Comparison Storage stabilities at 400** in days end. of storaga stability occurs with the start of sedimentation Rho-

I-

;F:

r- i

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Table 4: Test results of selected examples as automobile hydrofillers Stoving conditions Filler top coat Coating thickness in Ipm Filler top coat Pendulum hardness in sec Degree ef gloss <200 <600 Top coat adhesion characteristic value* Penetration characteristic value* Top coat condition characteristic val*** value Binder tested 15'165*C 17'140C 24 30 100 19% 62% CV 2-3 CV 1 CV 3 SUB 2 30'190°C 17'120°C -20 30 138 15% 57% CV 3 CV 1 CV 4 15'165*C 17'140C 35 27 130 67% 89% CV 2-3 CV 0-1 CV 2 SUB 4 30'190-C 17'120°C 38 25 144 61% 89% CV 2-3 CV 2 n.k.

30'130*C 17'140'C 31 38 113 67% 89% CV 3 CV 1 CV 2 SUB 5 15'165C 17'140-C 32 40 121 60% 87% CV 3 CV 0-1 CV 1 30'190°C 17'120°C 32 32 122 47% 82% CV 3 CV 2 n.k.

15'165'C 17'140-C 40 35 105 70% 89% CV 3 CV 0-1 CV 1-2 SUB 4 30'190'C 17'120'C 40 35 138 62% 88% CV 2-3 CV 0-1 n.k.

characteristic value assessment: Scharacteristic value assessment: characteristic value 9 complete loss of adhesion characteristic value 5 large number of penetrations characteristic value assessment: CV 1 very good characteristic value 1 very good characteristic value 5 deficient sP-PCI4 D I~I^CIIUi- i

~CT

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Claims

1. A water-dilutable, urethane-modified and hydroxyl group-containing binder, prepared by reaction of a polyester made by polycondensation of polyalcohols, hydroxy carboxylic acids, and polycarboxylic acids, with the exception of tri- and tetravalent polycarboxylic acids, all of which optionally contain further sulphonic or phosphonic acid groups, the polyester containing hydroxyl groups and neutralized and/or neutralizable acid groups with substoichiometric amounts (with respect to the number of free hydroxyl groups) of a partially blocked polyisocyanate.

2. The binder as claimed in claim 1, which contains hydroxyl groups of 3- 350, preferably 5-170 milliequivalents (OH)/100 g of solid resin.

3. The binder as claimed in at least one of the preceding claims, wherein the content of capped isocyanate groups, calculated as -NCO, is between and 15% by weight, with respect to solid resin.

4. The binder as "maimed in at least one of the preceding claims, wherein the content of ureth,,e groups, calculated as NH-C O- is between 0.5 and by weight, with respect to solid resin.

The binder as claimed in at least one of the preceding claims, which contains neutralizable and/or neutralized carboxylic acid and/or sulfonic acid and/or phosphonic acid groups.

6. The binder as claimed in claim 5, wherein the amount of neutralized carboxylic acid and/or sulfonic acid and/or phosphonic acid groups is between and 200, preferably 10-90, milliequivalents of sulfonate, carboxylate or phosphonate per 100 g of solid resin.

7. The binder as claimed in at least one of the preceding claims, which contains further coating agents DOC 37 AU3021192.VtP., DBM/KH:KP r r r r i I rr S~i i! iii; 23 and/or further binder components.

8. Use of the binder as claimed in at least one of the preceding claims in coating systems.

9. Use of the binder as claimed in at least one of the preceding claims as a stoving filler coating com- position for coating automobiles. Use of the binder as claimed in at least one of claims 1-8 as a stoving top coat. DATED this 17th day of December 1992. HOECHST AKTIENGESELLSCHAFT WATERMARK PATENT TRADEMARK ATTOREYS "THE ATRIUM" 290 BURWOOD ROAD HAWTHORN. VIC. 3122. t *I **g l oi c L kC 3 -C ll HF- 91/F 397 24 Abstract Water-dilutable, urethane-modified and hydroxyl group- containing self-crosslinking binder and formulations thereof Water-dilutable, urethane-modified and hydroxyl group- containing binder, .repred by reaction of a polyester containing hydroxyl .:ioups and neutralized and/or neutra- lizable acid groups with substoichiometric amounts (with respect to the number of free hydroxyl groups) of a partially blocked polyisocyanate. These binders are suitable for the production of coating ,films and other coatings of this type. Vv i