Powder coating composition for low temperature cure

摘要

Unsaturated polyester (A1) comprising endomethylenetetrahydrophthalic acid (HIMIC) units is new. (A1) Has at least 1.1 mmol unsaturation per gram polymer, where at least 1 mmol originates from the HIMIC units, and at least 0.01 mmol is derived from an alpha ,beta -unsaturated acid. Independent claims are included for the following: (1) powder coating composition comprising (A1) and an initiator; (2) preparation of (A1); (3) preparation of powder paint composition involving mixing (A1) and the initiator in an extruder at 20[deg]C lower than the half-life time temperature at 0.1 hour of the initiator; and (4) preparation of a coating on a substrate involving curing the composition applied on the substrate at 100 - 120[deg]C.