WATER-SOLUBLE RESIN

Abstract: The invention relates to a water-soluble resin that can be used as a dispersant. The resin is substantially built up from units of: A) polyethylene glycol with (5-100) ethylene oxide units, B) a compound containing one or more allyl and/or (meth)acrylate groups and C) the reaction product of one or more unsaturated fatty acids or one or more polyalcohol(s) wholly or partly esterified with unsaturated fatty acids with a compound, where the A:C molar ratio is between 0.5:1 and 4:1 and the B:C molar ratio is between 0.5:1 and 4:1.

Description: ATER-SOLUBLE RESIN The invention relates to water-soluble resins that can be used as dispersants. Water-soluble resins that can be used as dispersants are described in, for instance, 'Paint Flow and Pigment Dispersion' by T.C. Patton, pp 290-296 (1979). Dispersants known in the art such as, for instance, ' polyphosphates, isobutylene maleic acid copolymer-sodium salt and polyacrylateε, cannot be sufficiently mixed with binders such as, for instance, alkyd resin dispersions, to obtain paints with good gloss properties. It is possible also, for instance^ to use water-dilutable alkyd resins as dispersants for pigments. In order to obtain clear solutions and good properties, such as for instance pigment wetting properties, the known resins u&ed as dispersants will, moreover, have to be combined with undesired compounds such as, for instance, amines or organic solvents. The object of the invention is to provide a properly processable, air-drying and water-soluble resin suited as dispersant and resulting in paints with a good gloss. The water-soluble resin according to the invention is characterized in that the resin is substantially built up from units of: A. polyethylene glycol with (5-100) ethylene oxide units, B. a compound containing one or more allyl and/or (meth)acrylate groups and C. the reaction product of one or more unsaturated fatty acids or one or more polyalcohol(s) wholly or partly esterified with unsaturated fatty acids with an compound, where the A:C molar ratio is between 0.5:1 and 4:1 and the B:C molar ratio is between 0.5:1 and 4:1. The A:B molar ratio is mostly between 4:1 and 1:4 and is preferably substantially 1:1. Thus a low-viscosity, easily processable, air-drying and water-soluble resin is obtained. If used as a paint dispersant, this resin results in a paint with a good gloss and a good water resistance. For organic as well as inorganic pigments the resin has good pigment wetting properties. This resin, moreover, need not be combined with compounds such as, for instance, amines or organic solvents. Here it consequently also concerns solvent-free systems. Another advantage of the use of the resin as dispersant is that in the preparation of the paint there is hardly any foaming of the dispersant, so that hardly any or no anti-foaming agents need be added. According to a preferred embodiment of the invention, the A:C molar ratio is between 0.8:1 and 2:1 and the B:C molar ratio between 0.8:1 and 2:1. The best results are obtained if the A:B:C molar ratio is substantially 1:1:1. According to another preferred embodiment of the invention, the polyethylene glycol has (8-20) ethylene oxide units. Preferably the polyethylene glycol has (10-14) ethylene oxide units. The chosen number of ethylene oxide units is such that the resin continues to be water-soluble. The resin according to the invention can very well be used as a dispersant if it has the following characteristics: a number-average molecular weight M of between 1000 and 3000; a weight-average molecular weight M of between 2000 and 6000; a polydispersity M /'M of between 1.5 and 3.5; a viscosity of between 10 and 100 dPas, preferably between 10 and 30 dPas; - an iodine value of between 50 and 150 g iodine/100 grammes resin. The molecular weights have been determined via GPC (Ultra-styragel, Waters, 100A, lOOOA, 10,000A separating capacity M W 200- 300,000). The viscosity has been determined at 23°C using a rotational viscosimeter (DIN 53019, Bohlin). The iodine value has been determined via ASTM D 1959-85. As the polydispersity of the resin is between 1.5 and 3.5 hardly any preferential adsorption of high-molecular weight product takes place, so that no low-molecular weight product is left behind in the aqueous phase. As compound B may be used compounds containing allyl groups such as, for instance, allyl ethers with 3-20 carbon atoms, allyl alcohol, allylglycidyl ethers, diallyl ethers of glycerol, diallyl ether of trimethylolpropane or diallyl ethers of trimethylolethane and triallyl ether of pentaerythritol, as well as compounds containing acrylate groups such as, for instance, hydroxyethyl(meth)acrylate, hydroxylpropyl(meth)acrylate and hydroxybutyl(meth)acrylate. The compound used as B is preferably a compound containing allyl groups, such as allyl alcohol. Examples of polyalcohols wholly or partly esterified with unsaturated fatty acids are linseed oil, soybean oil, safflower oil, oiticica oil, caraway oil, rapeseed oil, wood oil and fish oil. Further can be used diesters and triesters of polyalcohols, such as glycerol, trimethylolpropane or pentaerythritol, and as unsaturated fatty acids the fatty acids of the above-mentioned unsaturated oils and tall oil fatty acid. Suitable unsaturated carbonyl compounds are maleic anhydride, fumaric acid or a functional (with, in addition to the unsaturation, another reactive group not being an unsaturation) acrylate. According to a preferred embodiment of the invention, C is the reaction product of linseed oil and/or safflower oil with maleic anhydride. The invention also comprises a process for the preparation of the present resin on the basis of A, B and C. In a first reaction step an unsaturated compound, preferably maleic anhydride, can react via radical reaction with an unsaturated vegetable oil, such as linseed oil or safflower oil, at a temperature above 150°C, so that C is obtained. Subsequently, after addition of an adduct of compounds A and B, alcohol-anhydride reactions can be carried out. These reactions usually take place in the presence of an appropriate catalyst such as, for instance, triethyl amine at temperatures lower than 150°C. The A:B molar ratio is mostly between 4:1 and 1:4 and is preferably substantially 1:1. In this process the A:C molar ratio is preferably between 0.5:1 and 4:1 and the B:C molar ratio preferably between 0.5:1 and 4:1. According to a further preferred embodiment of the invention the said ratios are between 0.8:1 and 2:1. More in particular the A:B:C molar ratio is substantially 1:1:1. The invention also comprises a modified resin obtained in that the resin described above, built up from A, B and C at temperatures lower than 150°C, is modified with one or more monofunctional epoxy compounds, preferably with a terminal copolymerizable double bond, such as for instance glycidyl(meth)-acrylate or glycidylallyl ether. The catalysts may be, for instance, triethyl amine or N,N-dimethylaniline. The molar ratio of the reactants is preferably substantially 1:1. This modification is preferably applied if the resin has free acid groups, because the epoxy compounds can then react with the acid groups present. This modified reaction product can subsequently react with acids or anhydrides such as, for instance, maleic acid(anhydride) . The resin according to the invention can be used as dispersant or grinding agent and/or wetting agent for pigments. A suitable pigment paste contains, for instance, 50-70% (wt) pigment, 3-7% (wt) resin according to the invention and 20-45% (wt) water. The dispersant can be used in water-based air-drying paint systems. In order to reach any desired pigment-volume concentration (PVC), alkyd dispersions, acrylate dispersions or mixtures of these can be added to the medium also. The effect of using the resin according to the invention as air-drying water-soluble dispersant is that the solubility and compatibility with, for instance, alkyd emulsions is substantially improved, so that good glossy systems are obtained. The resin according to the invention can be used also as water-soluble air-drying binder, or as water-soluble wood preservative in the form of copper or zinc salts of the resin. The resin according to the invention can further be used as air-drying plasticizer in, for instance, acrylate dispersions. Traditional plasticizers for acrylate dispersions are, for instance, (ethers of) ethylene and propylene glycols. These compounds, however, evaporate during the drying of the film, which is undesirable for, inter alia, environmental reasons. The resin according to the invention does not have this disadvantage. Another use of the resin is its use as drying emulsifier for the preparation of alkyd emulsions, and in acrylate dispersions. The resin according to the invention can be mixed with the customary additives for obtaining paint compositions. Examples of these additives are pigments, colourants, fillers, thickeners, flow-promoting agents, thixotropic agents, flatting agents, stabilizers and/or siccatives. The invention is elucidated by means of the following non-restrictive examples. Examples Example I Preparation of a resin In a four-necked flask provided with a nitrogen feed system, mechanical stirrer, thermocouple and dropping funnel, 98 parts by weight maleic anhydride was added at 215°C to 878 parts by weight linseed oil and. stirred at 215°C for such a length of time that no reflux of maleic anhydride was visible any more. The resulting product was an oil-like low-viscosity liquid with a total acid number of 115 mg KOH/gramme sample. Subsequently, after cooling to 130°C, 586 parts by weight allyl alcohol ethoxylated with 12 ethylene oxide units, as well as 0.3 part by weight triethyl amine, were added to this product. Finally, the whole was stirred for two hours at 130°C. The result was a low-viscosity oil-like product with the following properties: * solids content: 100% * M n : 2340 * polydispersity, M /M : 1.80 * iodine value: 110 g J-/100 g product * acid number: 35 mg KOH/g product * viscosity 23°C (Bohlin): 18.1 dPas Example II and Comparative Experiment A Preparation of a paint In a Cowless dissolver, a pigment paste based on a dispersant, titanium dioxide, thickener and demin water was prepared at 3000 rpm for 30 minutes according to Table I below. Subsequently, to 1 part by weight of this paste 2 parts by weight alkyd emulsion were added. Finally, siccativation took place using a cobalt (IΙ)-acetate solution. The total compositions of these paints and their properties are shown in the following table. TABLE I II Demin water Orotan 731 SD, 25% 1) Kronoε 2190 2) QR 1001 3) Resin according to Example I Uradil XP 515 AZ 4) 1750 1820 CoAcetate 6% 23 24 Pigment-volume concentration, % 20 20 Solids content, % 60 60 Viscosity 23°C, (DIN 53019), dPas 2.6 3.2 pH 7.20 6.80 BK drying time, stage 1 , min 40 30 BK drying time, stage 2, min 5) 80 60 BK drying time, stage 3, min ' 250 220 BK drying time, stage 4, min 300 275 -8- TABLE I (continued) Gloss 20° Gloss 60° Pendulum Hardness (ε), 1 day Pendulum Hardness (s), 1 week Adhesion to wood 6) Adhesion to alkyd 6) Water resistance ,6) after 1 week Adhesion wood.6) after 1 week Adhesion alkyd 6) , after 1 week 1) Orotan 731 SD: dispersant, isobutylenemaleic acid copolymer-εodium salt 2) Kronos 2190: titanium dioxide 3) QR 1001: polyurethane-based thickener 4) Uradil XP 515 AZ: alkyd emulsion of DSM Resins 5) The drying time was determined with a BK drying recorder (BYK-Chemie no.2710, Mickle Laboratory Engineering Co., Gomshall, Surrey, England). 6) Visual assessment where 1 = unacceptable 2 = insufficient 3 = reasonable 4 = good 5 = very good The gloss was improved considerably if, inεtead of the Orotan 731 disperεant, the resin according to the invention was used. Moreover, the other desired properties were retained. Examples III and Comparative Experiments B-C Example II was repeated, the amounts by weight being altered as indicated in Table II. Demin wate r Serad FX1010 (5%) Agitan 295 Serad FX508 Serad FA607 Orotan 731 (25%) Borchigen DFN Resin according to Example I 1.4 Tioxyde TR92 23.24 23.5 25.7 dispersed in pearl mill and added to: where: Serad FX1010: polyurethane-based thickener Agitan 295: anti-foaming agent Serad FX508: pigment wetting agent Serad FA607: pigment wetting agent -10- Orotan 731: dispersant, isobutylmaleic acid copolymer-sodium salt Borchigen DFN: pigment wetting agent Tioxyde TR 92: pigment Uradil XP 552AZ: alkyd emulsion of DSM Resinε Acrysol RM8: acrylate-containing thickener Aquacat: εiccative Siccatol 938: εiccative Serad FA 179: corroεion inhibitor Fluorad FC 129: wetting agent A paint composition based on the resin according to the invention resulted in a good gloεs and good pigment wetting properties.

Claims: CLAIMS 1. Water-soluble resin, characterized in that the resin is substantially built up from units of A. polyethylene glycol with (5-100) ethylene oxide units, B. a compound containing one or more allyl and/or (meth)acrylate groups and C. the reaction product of one or more unsaturated fatty acids or one or more polyalcohoK ε) wholly or partly esterified with unsaturated fatty acids with an unεaturated carbonyl compound, where the A:C molar ratio iε between 0.5:1 and 4:1 and the B:C molar ratio is between 0.5:1 and 4:1. 2. Resin according to claim 1, characterized in that the A:C molar ratio is between 0.8:1 and 2:1 and the B:C molar ratio is between 0.8:1 and 2:1. 3. Resin according to any one of claims 1-2, characterized in that the A:B:C molar ratio is substantially 1:1:1. 4. 2si according to any one of claimε 1-3, characterized in that the polyethylene glycol contains (8-20) ethylene oxide units. 5. Resin according to any one of claimε 1-4, characterized in that B iε a compound containing allyl groups. 6. Resin according to claim 5, characterized in that B iε allyl alcohol. 7. Resin according to any one of claims 1-6, characterized in that C iε the reaction product of linseed oil and/or safflower oil with maleic anhydride. 8. Procesε for preparing a resin substantially built up • from units of A, B and C according to any one of claimε 1-7, characterized in that, in a firεt reaction step, C is obtained via a radical reaction of an unsaturated carbonyl compound with an unsaturated vegetable oil at a temperature above 150°C, upon which C reacts with an adduct of compounds A and B, in which reaction the A:C molar ratio is between 0.5:1 and 4:1 and the B:C molar ratio is between 0.5:1 and 4:1. 5 9. Process according to claim 8, characterized in that the A:C molar ratio is between 0.8:1 and 2:1 and the B:C molar ratio is between 0.8:1 and 2:1. 10. Process according to any one of claims 8-9, characterized in that the A:B:C molar ratio is 10 substantially 1:1:1. 11. Process according to any one of claims 8-10, characte¬ rized in that the polyethylene glycol contains (8-20) ethylene oxide units. 12. Process according to any one of claims 9-11, characte- 15 rized in that B is a compound containing allyl groups. 13. Process according to claim 12, characterized in that B is allyl alcohol. 14. Process according to any one of claimε 8-13, characterized in that C iε the reaction product of 20 linseed oil and/or safflower oil with maleic anhydride. 15. Modified resin .composition based on a resin according to any one of claims 1-7 or a resin obtained according to any one of claims 8-14 and one or more monofunctional epoxy compounds. • 25 16. Use of a resin according to any one of claims 1-7 or 15 or use of a resin obtained according to any one of claimε 8-14. 17. Use of a resin according to any one of claims 1-7 or 15 or use of a resin obtained according to any one of 30 claims 8-14 as dispersant. 18. Water-soluble resin, proceεε, modified reεin compoεi- tion, use and use as disperεant aε described in substance and/or further elucidated in the examples.

Inventors: HOFLAND ADRIAAN, PONS DICK ADRIAAN, HOFLAND, ADRIAAN, PONS, DICK, ADRIAAN
Applicants: STAMICARBON, STAMICARBON B.V.
Application year: 1990
Main classification: C08F222
IPC codes: C08F220