Weatherable powder coatings
AssigneeEastman Chemical Company
InventorsYeong-Ho Chang, Robert B. Barbee
Life of this patent
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Abstract
This invention provides weatherable thermosetting powder coating compositions based on 1,2-cyclohexanedicarboxylic acid and 2,2,4,4-tetramethyl-1,3-cyclobutanediol. Coatings from this invention exhibit far superior QUV (313 bulb) resistance than compositions based on resins prepared from 1,3-and 1,4-cyclohexanedicarboxylic acid and are 20 times better than standard aromatic resin using the same cross-linking chemistry.
Claims21
A thermosetting powder coating composition which comprises,
- (a) a polyester comprised of from about 80 to 100 weight percent of residues of 1,2-cyclohexanedicarboxylic acid and from about 80 to 100 weight percent of residues of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and having a number average molecular weight of about 1500 to 10,000, and a glass transition temperature of about 45.degree. C. to 100.degree. C.;
- and
- (b) a cross-linking agent reactive with said polyester
- wherein said composition, after application to a substrate and curing, provides a coating which possesses a QUV resistance of at least 5000 hours, said resistance determined by the number of hours required to reduce the original gloss of said coating by 50%, wherein said coating is alternately exposed to an illuminated 313 nm fluorescent tube at 45.degree. C. for an 8 hour period followed by a 4 hour period of darkness at 45.degree. C.
A thermosetting powder coating composition which comprises,
- (a) a polyester which consists essentially of residues of 1,2-cyclohexanedicarboxylic acid, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and up to 10 weight percent of a trifunctional monomer residue selected from residues of the group consisting of trimethylolethane, trimethylolpropane, glycerol, and trimellitic anhydride, and having a number average molecular weight of about 1500 to 10,000, and a glass transition temperature of about 45.degree. C. to 100.degree. C.;
- and
- (b) a cross-linking agent reactive with said polyester
- wherein said composition, after application to a substrate and curing, provides a coating which possesses a QUV resistance of at least 5000 hours, said resistance determined by the number of hours required to reduce the original gloss of said coating by 50%, wherein said coating is alternately exposed to an illuminated 313 nm fluorescent tube at 45.degree. C. for an 8 hour period followed by a 4 hour period of darkness at 45.degree. C.
A polyester comprised of from about 80 to 100 weight percent of residues of 1,2-cyclohexanedicarboxylic acid and from about 80 to 100 weight percent of residues of 2,2,4,4-tetra-methyl-1,3cyclobutanediol, and having a number average molecular weight of about 1500 to 10,000, and a glass transition temperature of about 45.degree. C. to 100.degree. C.
A polyester which consists essentially of residues of 1,2-cyclohexanedicarboxylic acid, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and up to 10 weight percent of a trifunctional monomer residue selected from residues of the group consisting of trimethylolethane, trimethylolpropane, glycerol, and trimellitic anhydride, and having a number average molecular weight of about 1500 to 10,000, and a glass transition temperature of about 45.degree. C. to 100.degree. C.
Dependencies are inferred from the claim text.