Powder coating prepn. - by graft polymerising substrate polymer with a hydroxy-alkyl (meth)acrylate and an unsaturated carboxylic acid

摘要

A powder coating esp. for metals is prepd. bt graft polym erising a substrate polymer (I) with a monomer mixt. comprising 2-25% (w.r.t. monomer mixt) of a monohydroxyester (II) of an unsatd. carboxylic acid with a 2-10C polyol and 0.3-6% unsatd. 3-6C carboxylic acid (III). (I) has tg =0 degree C and is used in an amt. of 1.10% w.r.t. the graft copolymer. A copolymer of the monomer mixt. could have a Tg >=10 degrees C. The coating has good melt flow and hardening properties. In an example of an aq polybutylacrylate dispersion was graphed with propylene glycol methacrylate acrylic acid, butyl acrylate, methyl acrylate and methyl methacrylate to give a coating having Erichsen value 9.5mm.