GB823224A - Improvements in and relating to the preparation of polyesters - Google Patents

Abstract

Thermoplastic polyesters containing D 4-tetrahydrophthalic acid groups of the formula <FORM:0823224/IV (a)/1> where R1-6 are any of H, alkyl, aryl, or acyl, or OH and esters thereof, R1 or R2 may form endo(m)ethylene bridges with R5 or R6, and R7-8 are H or lower alkyl groups, the polyester having more than 10 ester groups in the molecule and an M.W. of at least 2000, are prepared by subjecting a linear polyester containing dienophilic groups to a dienic addition reaction with a compound having a single system of conjugated double bonds. This reaction is preferably performed at 0-120 DEG C. in the presence of an inhibitor such as 1,2-dinitrobenzene or hydroquinone, and the conjugated diene may be used in an equivalent or less than equivalent amount with respect to the dienophilic groups in the polyester. The polyesters may be derived from butene dioic acids such as maleic or fumaric, with or without such saturated acids as succinic, glutaric, adipic, sebacic, tartaric, acetonedicarboxylic, 3-ketopimelic, or terephthalic and from diols such as hexane diol (1,6), butane diol (1,4), butylene glycol, butene diol and diethylene glycol, with or without such monohydric alcohols as octanol. Conjugated dienes specified are butadiene, cyclopentadiene, cyclohexadiene, and 2-ethyl, 1,3-hexadien-1-ol esters (e.g. acetate). The resultant polymers may be dissolved in chlorobenzene, mixed with unspecified vinyl or acrylic resins or with cellulosic derivatives, or may have their D 4 unsaturation epoxidized, halogenated, hydrogenated or hydrohalogenated. Addition polymers.-In the case when the conjugated diene is used in less than the equivalent amount with respect to the dienophilic groups in the polyester, the remaining ethylenically unsaturated groups may be copolymerized with styrene in the presence of methyl ethyl ketone peroxide and either cobalt naphthenate or dimethyl aniline.