| 摘要 |
A thermosetting powder coating system on the basis of epoxide gp.-contg. amorphous and/or semi-crystalline copolyesters is new and comprises: (A) at least one glycidyl ether gp.-contg. amorphous and/or semicrystalline copolyester pref. having an epoxide no. of 0.018-0.510 (equiv./100 g); (B) an aliphatic and/or cycloaliphatic polybasic acid and/or its anhydride and/or a polyol-modified anhydride of a polybasic acid and/or an amorphous or semicrystalline carboxyl-functional copolyester (pref. having an acid no. of 10-200 (mg KOH/g) and a glass transition temp. of > 40 degrees C) and/or a carboxyl-functional acrylate resin (pref. having an acid no. of 10-300 (mg KOH/g); and (C) if required, fillers and/or pigments and/or additives, where (A) has a mol. wt. of 300-10000 and is prepd. by reacting a hydroxyl-functional copolyester (D) with epihaloalkanes (E). Pref. the amorphous copolyester (D) pref. has a hydroxyl no. of 10-2000 (mg KOH/g) and a glass transition temp. of at least 40 degrees C and contains component selected from terephthalic acid, isophthalic acid, adipic acid, trimellitic acid anhydride, neopentyl glycol, ethylene glycol and trimethylol propane esp. 0-95 mol.% cyclohexane dicarboxylic acid, 100-5 mol.% isophthalic acid and neopentyl glycol. The semicrystalline copolyester (D) has a hydroxyl no. of 10-400 (mg KOH/g) and contains decane dicarboxylic acid and hexane diol. Pref. (B) is present in an amt. corresponding to 0.4-1.4 (esp. 0.8-1.2) carboxyl gps. and/or anhydride gps. per epoxide gp. of (A). Pref. (E) is selected from 1-chloro-2,3-epoxy propane (epichlorohydrin), 1-chloro-2-methyl-2,3-epoxy propane, 1-chloro-2,3-epoxy butane and epibromohydrin. A is produced in two stages, first the attachment of epihaloalkanes to the hydroxyl gps. of (D) in the presence of a Lewis acid. |
