Abstract: The invention relates to unsaturated homo- and/or copolymerizable polyesters which have been prepared from an alcohol component comprising a multivalent alcohol, a carboxylic acid component comprising a multivalent carboxylic acid and optionally, hydroxycarboxylic acids or their derivatives capable of forming esters, and an acid component selected from the group consisting of maleic acid, fumaric acid, itaconic acid, mesaconic acid, aconitic acid, their derivatives capable of forming esters and mixtures thereof. As part of the alcohol coponent, hydroxylated polybutadiene with an average molecular weight of 2400 to 3000 and a hydroxy-functionality of 2.2 to 2.4 is condensed into the polyester. The polyesters exhibit useful flow anomalies which are due to their molecular structure.

Abstract: The invention is related to unsaturated homo- and/or copolymerizable linear polyesters which are prepared from diols and at least one unsaturated dicarboxylic acid or its derivatives capable of forming esters. The polyesters contain as component (A) a diol with end-position hydroxyl groups and an average molecular weight of 700 to 1200; as component (B) one or more unsaturated dicarboxylic acids; and as component (C) a linear diol with 2 to 6 carbon atoms. The equivalent ratio of A:B is from about 0.8:1 to 1.2:1 and the equivalent ratio of C:(A+B) is from about 0.5:1 to 1:1.