Powder coating composition and its use

摘要

Coating powders (I) for the prodn. of non-yellowing, tough/resilient, solvent- and chemical-resistant coatings which are cured at temps. of at least 120 degrees C, contain (A) a binder, (B) a hardener with a m.pt./range of 40-160 degrees C consisting of (i) 4-20C (cyclo)aliphatic dicarboxylic acid, (ii) monomeric and/or polymeric anhydrides of (i), (iii) polyol-modified polymeric anhydrides of (i) or (iv) 4-18C aliphatic hydroxy-acids, opt. with (C) uretedione gp.-contg. poly-addn. prods. as additional crosslinkers and opt. (D) other paint additives. Binder (A) comprises copolymer(s) with a Tg of 30-80 degrees C, a Mn of 1000-6000 and a ratio of Mw/Mn = 2.5-10.0, derived from (i) 4-50 wt.% 1-18C (cyclo)alkyl, aryl and/or aralkyl esters of unsatd. mono- and/or di-carboxylic acids, (ii) 26-45 wt.% glycidyl (meth)acrylate, (iii) 1-8 wt.% maleic and/or itaconic anhydride and (iv) 20-69% vinylaromatics. The wt. ratio of (A):(B) is such as to provide 0.5-1.5 COOH and/or anhydride gps. per epoxide gp. in (A).