THERMOPLASTIC COMPOSITIONS ON THE BASIS OF POLYESTERS FOR INJECTION-MOULDING PURPOSES AND A PROCESS FOR PREPARARING THEM.

摘要

1331765 Polyester compositions FARBWERKE HOECHST AG 8 Oct 1970 [8 Oct 1969] 47970/70 Heading C3R In a process for the production of a crystalline thermoplastic polyester moulding composition, a dialkyl ester of a low molecular weight alcohol with, as acid component, an aromatic dicarboxylic acid is transesterified with a saturated aliphatic or cycloaliphatic diol and the ester thus formed is subjected to melt condensation and subsequent solid phase condensation to a reduced specific viscosity value, as measured with a solution of 1% by weight in phenol and tetrachloroethane 60 : 40 at 25‹ C. of 0À9 to 2À0 dl/g., there being added during transesterification or at the beginning of or in the course of melt condensation (a) 0À02-2% by weight calculated on the dialkyl ester used of inert inorganic solid material, e.g. talcum, kaolin, titanium dioxide, aluminium oxide, pyrophyllite, sodium fluoride or boron nitride, having a particle size of less than 5 Á and (b) 0À02-0À3% by weight calculated on the dialkyl ester used of one or more epoxides of the formula in which up to three of the radicals R, R1, R11 and R111 may represent hydrogen, and the others, which may be the same or different, each represents an alkyl, cycloalkyl, aryl or aralkyl group, optionally containing ether oxygen, and one of these groups contains an additional epoxide group. The epoxide may be ethylene glycol diglycidyl ether, butane diol (1,4)-diglycidyl ether, neopentyl glycol diglycidyl ether, 1,4-dimethylol cyclohexane diglycidyl ether, 1- vinyl - cyclo - hexene - 3 - diepoxide, 1,2 - divinyl cyclohexane diepoxide, hexadiene-(1,5)- diepoxide or the diglycidyl ether of hydroquinone, resorcinol or bis-phenol-A. Melt condensation may be carried out until a RSV value of 0À6-1À1 dl/g. is obtained. Granulated moulding compositions may be coated with paraffin wax, montan wax salts, montan wax ester salts or alkali metal paraffin sulphonates or olefin sulphonates, and may contain less than 0À01% by weight of water. Moulding may be effected at a temperature of at least 100‹ C. In examples transesterification of dimethyl terephthalate with ethylene glycol is effected in the presence of manganese acetate, the bisglycidyl ether of bisphenol A or 1,4-butane diol and boron nitride or sodium fluoride are added together with Sb 2 O 3 or GeO 2 and polycondensation effected.