Thermosettable polyesters, powder coating compositions containing them and coated substrates.

摘要

Thermosettable polyester resin compositions, suitable for use in powder coating applications are derived from a polymerization reaction mixture comprising a dicarboxylic aromatic component (e.g., 1.4-benzenedicarboxylic acid), a trihydroxy alkyl component [e.g., 2-ethyl-2-(hydroxymethyl)-1,3-propanediol], a diol component (e.g., 2,2-dimethyl-1,3-propanediol) and a dihydroxy alkyl compound having 4 to 10 carbon atoms in the primary carbon chain between the hydroxyl moieties (e.g., 1,6-hexanediol). Polyesters of the present invention have a number average molecular weight of from about 2,000 to about 6,000, a combined acid and hydroxyl number of from 35 to 70 milligrams of KOH per gram of polyester, and a glass transition temperature of from 35°C to 50°.