PURPOSE: To obtain a molded composite polyester resin article improved in thermal shock resistance by molding a resin compsn. comprising an unsatd. polyester resin having a specified heat distortion temp. and an inorg. filler.

CONSTITUTION: This molded article, having an improved thermal shock resistance to rupture of at least 600 cycles according to the more strict form of ANSI test Z 124,3, is prepd. by molding a composite compsn. comprising about 60-80 wt.% inorg. filler and about 20-40 wt.% unsatd. polyester. Such an improved thermal shock resistance is directly related to the use of an unsatd. polyester resin which in the unfilled state gives a cured item having a heat distortion temp. of about 68-78°C. Thus is obtd. a molded polyester article improved in thermal shock resistance.