Patent EA-000690-B1 (EA)
Title: Powered thermosetting composition for coatings
Inventor: MOENS LUC
IPC: C08L67/02
Filed: 1996-12-05
Abstract: 1. Powered thermosetting composition including a binder consisting of a mixture of polyesters containing carboxyl groups and a cross-linking agent with functional groups capable of reacting with carboxyl groups wherein polyesters comprise: a) a semi-crystalline polyester containing carboxyl groups and consisting of 85-100 mol % of 1,4 cyclohexanediol and 0-15 mol % at least one other aliphatic and/or cycloaliphatic polyol, based on the total of alcohols; and 85-100 mol % of a straight-chain saturated dicarboxylic aliphatic acid having 4-14 carbon atoms, and 0-15 mol % of at least one other aliphatic and/or cycloaliphatic and/or aromatic polycarboxylic acid, based on the total of acids; and b) an amorphous polyester containing carboxyl groups and consisting of 70-100 mol % isophthalic acid and 0-30 mol % of at least of at least one other aliphatic and/or cycloaliphatic and/or aromatic polycarboxylic acid, based on the total of acids and 70-100 mol % of neopentylglycol and/or 2-butyl-2-ethyl-1,3-propanediol, and 0-30 mol %of at least one other aliphatic and/or cycloaliphatic polyo, based on the total of alcohols. 2. A composition of claim 1, characterized in that the straight-chain saturated dicarboxylic aliphatic acid, present in the semi-crystalline ester (a) is selected from succinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic acids and anhydrides thereof taken separately or in a mixture, preferably is an adipic acid. 3. A composition of claim 1 or 2, characterized in that the polycarboxylic acid, present in the semi-crystalline ester (a) is selected from 1,4-cyclohexanedicarboxylic, fumaric, maleic, trimellitic, pyromellitic acids and anhydrides thereof taken separately or in a mixture. 4. A composition of any claim 1-3, characterized in that the polyol, present in the semi-crystalline ester (a) is selected from ethylene glycol, propylene glycol, 1,4-butandiol, 1.6-hexanediol, 1,4-cyclohexanedimethanol, hydrated bisphenol A, trimethyllopropane, ditrimethylopropane, trimethyloethane, pentaerythritol and mixtures thereof. 5. A composition of any claim 1-4, characterized in that the semi-crystalline ester (a) has an acid number from 10 to 70 mg KON/g, preferably from 15 to 40 mg KON/g. 6. A composition of any claim 1-5, characterized in that the semi-crystalline ester (a) has an average molecular weight between 1600 and 17000, preferably between 2800 and 11200. 7. A composition of any claim 1-6, characterized in that the semi-crystalline ester (a) has a fusion viscosity from 5 to 10000 mPa.s, measured at 175 degree C by viscosimeter with a cone and a plate. 8. A composition of any claim 1-7, characterized in that the semi-crystalline ester (a) has a fusion temperature of about 60 to 140 degree C. 9. A composition of any claim 1-8, characterized in that the semi-crystalline ester (a) has a glass transition temperature between about 40 to 80 degree C. 10. A composition of any claim 1-9, characterized in that the polycarboxylic acid, present in the amorphous polyester (b) is selected from fumaric, maleic, o-phtalic, terephtalic, 1,2-cyclohexanedicarboxylic, 1,3-cyclohexanedicarboxylic, 1,4-cyclohexanedicarboxylic, trimellitic, pyromellitic acids, 1,4-cyclohexanedicarboxylic, succinic, glutaric, adipic, pimelic, suberic, azelaic, sebacic, trimellitic, pyromellitic acids and anhydrides thereof taken separately or in a mixture. 11. A composition of any claim 1-10, characterized in that the polyol, present in the amorphous polyester (b) is selected from ethylene glycol, diethylene glycol, propylene glycol, 1,4-butandiol, 1.6-hexanediol, 1,4-cyclohexanedimethanol, 2-methyl-1,3-propanediol, hydrated bisphenol A, hydroxypivalate neopentylglycol, trimethyllopropane, ditrimethylopropane, trimethyloethane, pentaerythritol and mixtures thereof. 12. A composition of any claim 1-11, characterized in that the amorphous polyester (b) has an acid number from 15 to 100 mg KON/g, preferably from 30 to 70 mg KON/g. 13. A composition of any claim 1-12, characterized in that the amorphous polyester (b) has an average molecular weight between 1100 and 11500, preferably between 1600 and 8500. 14. A composition of any claim 1-13, characterized in that the amorphous polyester (b) has a fusion viscosity from 5 to 15000 mPa.s, measured at 200 degree C by viscosimeter with a cone and a plate. 15. A composition of any claim 1-14, characterized in that the amorphous polyester (b) has a glass transition temperature between about 40 to 80 degree C. 16. A composition of any claim 1-15, characterized in that the polyester mixture contains from 5 to 45, preferably from 10 to 30 weight parts of the semi-crystalline polyester, containing carboxyl groups (a) and from 55 to 95, preferably from 70 to 90 weight parts of the amorphous polyester (b), based on the total weight of polyesters. 17. A composition of any claim 1-16, characterized in that the cross-linking agent is a polyepoxyde composition. 18. A composition of claim 17, characterized in that the polyepoxyde composition is a triglycidyle isocyanurate. 19. A composition of any claim 1-16, characterized in that the cross-linking agent is a β-hydroxyalkylamide. 20. A composition of any claim 1-16, characterized in that the cross-linking agent is an acrylic copolymer, containing glycidyle groups. 21. A composition of any claim 1-20, characterized in that the cross-linking agent is taken from 0,25 to 1,4, preferably from 0,6 to 1,05 of carboxy group equivalent, present in semi-crystalline polyester (a) and amorphous polyester (b)per epoxy or β-hydroxyalkyl equivalents.  22. A composition of any claim 1-21, characterized in that contains from 4 to 50 weight parts of the cross-linking agent, from 5 to 38,4 weight parts of semi-crystalline polyester (a) and from 30 to 86,4 weight parts of the amorphous polyester (b), based on the total weight of the cross-linking agent and the polyesters. 23. A composition of any claim 1-22, characterized in that further contains to 5% based on the total weight of the polyesters (a) and (b), a catalyst of the cross-linking formation. 24. A composition of any claim 1-23, characterized in that contains to 10%, based on the total weight of the polyesters (a) and (b), at least one stabilizer selected from compositions absorbing ultraviolet radiation and/or steric hindered amines. 25. A method of articles coating, preferably metal articles, characterized in that powered thermosetting composition according to any claim 1-24 is applied on said article by pulverization using electrostatic or triboelectric pistol or placing in a fluidized bed, and thus obtained coating is subjected to setting at a temperature from 150 to 220 degree C during from about 5 to 35 minutes. 26. Articles coated completely or partially using a method according to clam 25.