GB579462A - Improvements relating to the manufacture of highly polymeric substances - Google Patents

Abstract

Polyesters are produced by treating glycols of the formula HO(CH2)nOH with an acid of the general formula HOOC6H4-O-(CH2)n-O -C6H4-COOH, or a lower dialkyl or diaryl ester or acid chloride of such an acid. In the general formul n represents an integer greater than 1 and preferably is in each case, even. The acid or derivative thereof may be reacted with excess glycol preferably in an atmosphere of inert gas, the excess glycol removed by distillation in vacuo and the low polymeric ester thus obtained, heated above its melting point in an inert gas or in vacuo with introduction of a small quantity of gas through a capillary until the product is capable of yielding by extrusion or drawing in the molten state films which may be cold drawn to several hundred per cent of their length. When using a lower dialkyl ester of the acid, a metal, ester interchange catalyst, e.g. sodium, lithium, potassium, calcium, magnesium, zinc, cadmium, manganese, iron, nickel, cobalt, tin, lead or bismuth, or small amounts of alkali metal mixed with other metals may be employed. Alkali or alkaline earth metals may be added as solution in the glycol or in lower alcohols, such as methanol. Other metals may be used, e.g. as powder, chips, ribbon, or wire. The reaction with an acid chloride is carried out in presence of an organic base, e.g. pyridine, with or without the addition of an inert solvent, and the second part of the reaction is preferably catalysed with a metal. When using the diaryl ester of the acid, alkali carbonates may be present in the first part of the reaction. Examples describe the preparation of polyesters from (1), (2) and (3) diethyl diphenoxy ethane 4,41-dicarboxylate and ethylene glycol in presence of lithium or lithium and magnesium and in an atmosphere of nitrogen. Trimethylene, pentamethylene, hexamethylene or decamethylene glycols may also be used. Other esters mentioned are diethyl diphenoxybutane-4,41-dicarboxylate, diethyl-diphenoxypentane-4,41-dicarboxylate and diethyl-diphenoxyhexane-4,41-dicarboxylate; (4) diethyl-diphenoxypentane-4,41-dicarboxylate and hexamethylene glycol; (5) diethyl-diphenoxyhexane-4,41-dicarboxylate and decamethylene glycol; (6) diphenoxyethane-4,41-dicarboxylic acid and ethylene glycol; (7) diphenyl-diphenoxyethane - 4,41 - dicarboxylate and ethylene glycol in presence of potassium carbonate; (8) diphenoxyethane-4,41-dicarboxylic acid chloride and ethylene glycol in presence of pyridine and chloroform. Example (9) describes the spinning of the high polymer obtained according to example (2) into a lustrous filament by extrusion in an atmosphere of nitrogen followed by cold drawing up to 400 per cent. The diphenoxy-alkane-4,41-dicarboxylic acids may be prepared by reacting 2 mols. of di-sodium or di-potassium-4-hydroxy-benzoate with one mol. of the appropriate alkylene dihalide in an inert solvent, such as toluene, extracting with water and acidifying the aqueous layer or they may be prepared by hydrolysis of their lower dialkyl esters which may be prepared by refluxing two mols. of the sodium or potassium salt of, e.g., the methyl or ethyl ester of 4-hydroxy benzoic acid with one mol. of the appropriate alkylene dihalide in alcohol. The diphenyl esters of the diphenoxyalkane-4,41-dicarboxylic acids may be prepared by heating the corresponding acid chlorides, which are prepared by heating the free acids with a mixture of phosphorus pentachloride and phosphorus oxychloride, with an excess of phenol in xylene. Specification 578,079 is referred to in the first Provisional Specification.