| 摘要 |
<p>Liq. coating compsn. comprises a binder mixt. contg., by wt., (A) 45-5% aminoplasts and (B) 55-95% of at least bifunctional, mainly free OH and opt. free COOH end gp.-carrying linear polyesters or polyester mixts. having mol. wt. 1500-5000. The polyesters (B) are prepd. by condensing a diol mixt., (I), with a dicarboxylic acid mixt. (II). Novelty consists in using, as (I), a mixt. of (i) 5-30 mol. % butanediol-1,3 or -1,4, (ii) 95-70 mol. % neopentyl glycol, opt. replaced by up to 60 mol. % propanediol-1,2, w.r.t. neopentyl glycol, and (iii) 0-30 mol. % further diols contg. prim. and/or sec. OH gps. separated by a chain of >=3C. (II) is a mixt. consisting of (i) 95-70 mol. % of >=1 aromatic dicarboxylic acid which can be replaced by up to 30 mol. %, w.r.t. all aromatic acids, of cycloaliphatic dicarboxylic acids, and (ii) 5-30 mol. % of >=1 aliphatic dicarboxylic acid. The compsn. yield smooth, crater-free coatings after stoving, even when applied as thin layers and stoved after a very short exposure to air. The coatings adhere well to metals, and resist corrosion and weathering.</p> |
