UNSATURATED POLYESTER RESINS MODIFIED BY SUBSTITUTION, WITH LACTIC ACID, OF AN ACID AND ALCOHOL COMPONENT OF THE POLYESTER

摘要

The invention relates to an unsaturated polyester resin comprising a) a lactic acid-modified unsaturated polyester and b) a copolymerizable comonomer, with a substitution, with lactic acid, in the composition of an initial polyester, of: i) up to 90 mol% of phthalic anhydride of the acid component of the initial polyester, wherein the acid component comprises from 80 to 20 mol% of maleic anhydride (MA) or fumaric acid, and from 20 to 80 mol% of phthalic anhydride (PA), the polyol component of the initial polyester comprising from 50 to 100 mol% of propylene glycol (PG) and from 0 to 50% of a polyol among ethylene glycol (EG), diethylene glycol (DEG), dipropylene glycol (DPG) and/or 1,3-butylene glycol and/or 1,4-butanediol and/or neopentyl glycol (NPG), ii) up to 100% of a polyol among DPG and DEG, present at an overall initial molar content ranging up to 50% of the polyol component of the initial polyester and also comprising PG, with the acid component of the initial polyester being maleic anhydride (MA) or fumaric acid, optionally in the presence of up to 20 mol%, relative to the acid component, of phthalic anhydride (PA), and in this case with a substitution also of the initial phthalic anhydride (PA), with the lactic acid, ranging up to 100%, and with the molar ratio of lactic acid relative to the acid component, without including the lactic acid, of said polyester a) being at most 1.75. The invention also relates to a thermosetting composition comprising the resin, and to the uses of these thermosetting compositions and resins in moulding compositions or in general purpose compositions.