Polyester as additive in coating compositions

摘要

The polyesters (I) are obtd. by reacting: (a) 5-50 pts. wt. linear or branched (cyclo)aliphatic di or polyhydric alcohol(s), (b) 2-40 pts. wt. at least di-basic aromatic carboxylic acid(s), (c) 0-40 pts. wt. 2-alkenyl-dicarboxylic acid anhydride(s), (d) 10-30 pts. wt. at least di-basic linear or branched aliphatic carboxylic acid(s), (e) 0-15 pts. wt. linear or branched aliphatic hydroxy-acid, (f) 0-15 pts. wt. linear or branched aliphatic polyamine with at least 1 prim. and at least 1 sec. or tert. amino gp., (g) 0-15 pts. wt. glycidyl ester of a branched aliphatic monocarboxylic acid or glycidyl ether of a branched aliphatic alcohol, and (h) 0-15 pts. wt. polyhydroxyamine. Also claimed are: (i) aq. dispersions of polyesters (I), (ii) polyester solns. contg. (I) with a solvent contg. water-miscible organic solvent(s) (pref. half-ethers of aliphatic diols) and water, (iii) processes for the prodn. of these dispersions and solns., (iv) electrophoretic coating baths contg. (I), and (v) a process for coating galvanised steel sheet in an electrophoretic coating bath contg. (I).