The invention concerns powder thermosetting coating compositions comprising (a) an amorphous polyester containing carboxyl groups, rich in isophthalic acid and neopentylglycol, optionally branched with a polycarboxylic acid or a polyol containing at least three functional groups; (b) a semicrystalline polyester containing carboxyl groups prepared from one or several saturated aliphatic dicarboxylic acids with linear chain, and from a saturated aliphatic diol with linear or cyclic chain optionally branched with a polycarboxylic acid or with a polyol containing at least three functional groups, and having a melting point (Tm) of at least 40° C. and an acid value of 5 to 50 mg of KOH/g, and (c) a cross-linking agent. Said compositions are useful for preparing powder paints and varnishes providing excellent quality coatings whereof the brilliance measured at an angle of 60°, according to the ASTM D 523 standard is always less than 50%, that is half-gloss or matt coatings.
本发明涉及粉末热固性涂料组合物,其中包括 (a) 含有羧基的无定形聚酯,富含
间苯二甲酸和
新戊二醇,可选择与含有至少三个官能团的聚
羧酸或多元醇进行支化;(b) 含羧基的半结晶聚酯,由一种或几种线性链的饱和脂肪族二
羧酸和线性 链或环状链的饱和脂肪族二元醇制备而成,可选择用聚
羧酸或至少含三 个官能团的多元醇进行支化,熔点 (Tm) 至少为 40 摄氏度(c)
交联剂。上述组合物适用于制备粉末涂料和清漆,可提供质量上乘的涂层,根据 ASTM D 523 标准,在 60°角处测量的亮度始终低于 50%,即半光或无光涂层。