GB839404A - New polyesters - Google Patents

Abstract

New polyesters, suitable for the manufacture of mouldings, films, lacquers and protective coatings have repeated units of the formula: <FORM:0839404/IV (a)/1> The polyesters may be made (1) by reacting an aqueous solution of a di-alkali metal salt of 2,2 - (4,41 - dihydroxy diphenyl) propane with a solution of the acid chloride or bromide of 4,41-dicarboxy diphenyl ether in a non-solvent for the polyester (e.g. benzene or toluene) or in a solvent for the polyester (e.g. methylene chloride, 1,2 - dichloroethane, 1,1,2 - trichloroethane or tetrachloroethane); catalysts for the reaction being trimethyl (or triethyl) benzyl ammonium hydroxide or chloride; (2) by heating equimolecular proportions of 2,2-(4,41-dihydroxy diphenyl) propane and the acid chloride or bromide of 4,41-dicarboxy diphenyl ether; (3) by heating at about 200 DEG C. 1 mol. of 2,2-(4,41-dihydroxy diphenyl) propane with slightly more than 1 mol. of the dimethyl, diethyl, dipropyl or dibutyl ester of 4,41-di-carboxy diphenyl ether and 1.5 mols. of a polymethylene glycol containing 2-10 carbon atoms in the presence of an ester-interchange catalyst whereby alkyl alcohol is distilled off and then heating at about 300 DEG C. to distil off most of thepoly methylene glycol; specified ester-interchange catalysts being lead oxide; alcoholates or glycolates of the alkali metals, the alkaline earth metals or magnesium; borates or carbonates of the alkali metals; magnesium oxide; and esters of ortho-titanic acid; (4) by effecting ester-interchange between the diacetate of 2,2-(4,41-dihydroxy diphenyl) propane and 4,41-dicarboxy diphenyl ether or its dimethyl ester. The molecular weight of the polyesters may be increased by heating them above their melting point in vacuo or by heating them in powder form at just below their sintering temperature. Before use the polyesters are preferably dried by heating them at 110-120 DEG C. in vacuo. The polyesters may be used in the manufacture of housings, gears, bearings, bushings and electrical components. The polyester films may be used in the manufacture of container liners, electrical insulating tapes and sound recording tapes. Plasticizers, stabilizers, fillers, dyes or pigments may be added.