GB588497A - Manufacture of new highly polymeric linear esters and the production of filaments, fibres and the like therefrom - Google Patents

Abstract

Highly polymeric linear polyesters are obtained by heating a mixture of a dicarboxylic acid of formula <FORM:0588497/IV/1> (where x=0, 1, 2, 3 or 4) or an ester-forming derivative thereof and at least one molecular proportion of a glycol of general formula HO-(CH2)y-OH (where y=2, 3, 4, 5 or 6) or a low molecular weight product obtained by condensation from the ingredients of the above mixture, volatile by-products and excess glycol being removed at least during the later stages of the reaction which is continued until filaments formed from the melt can be cold-drawn to form useful fibres. Polyester-forming derivatives of the acids are aliphatic, cycloaliphatic or aryl esters (including half esters) thereof, acid halides, or ammonium or amine salts thereof. When using the acid, a large excess of glycol is usually employed and heating is usually at or above the boiling point of the mixture. When using an ester of the acid, a smaller excess of glycol is sufficient and heating is usually at a temperature above the melting point of the mixture and above the boiling point of the alcohol or phenol being replaced, but below the boiling point of the glycol. When using a dihalide, the reaction is usually performed in an inert diluent in presence of a base such as pyridine, N-methylpiperidine, N-dimethylaniline or N-diethylaniline. An ester interchange catalyst or mixture of catalysts may be employed when using an ester as starting material. Suitable ones are metals which are listed in the Specification in the form of powder, chips, shavings, ribbons or wire. Alkali, alkaline earth metal or magnesium may be used as alcoholates formed by dissolving them in the glycol employed or in a monohydric alcohol. Alkali metals may also be used as carbonates or borates. Magnesium may be used as its oxide. During part of the reaction, pressure may be reduced to facilitate removal of the glycol. Oxygen is preferably removed and, if desired, a stream of oxygen-free gas, e.g. nitrogen, is passed through and/or over the reaction mass. The molten product may be extruded from the reaction vessel and formed into blocks, chips or other shapes. Filaments can be formed by extrusion or by drawing from the melt, and may be cold drawn, this term being defined as including drawing during and/or after passage through hot water or steam. Films, mouldings or coatings may also be formed from the molten polyesters which may also be used as adhesives, plasticisers, binders for coating compositions or bonding agents for laminated fabrics. Examples describe the preparation of polyesters from (1) methyl diphenylmethane - 4,41 - dicarboxylate, and ethylene glycol with lithium and magnesium as catalysts; (2) methyl-a : d -diphenylbutane-4,41-dicarboxylate and ethylene glycol with the same catalysts; (3) ethyl diphenylmethane-4,41-dicarboxylate and trimethylene glycol with the same catalyst; (4) a b -diphenylethane-4,41-dicarboxylic acid and ethylene glycol; (5) the salt obtained by dissolving in aqueous triethylamine a b -diphenylethane-4,41-dicarboxylic acid and ethylene glycol; (6) ethyl a b -diphenylethane - 4,41 - dicarboxylate, hexamethylene glycol with lithium and magnesium as catalysts; (7) methyl - a : g - diphenylpropane - 4,41 - dicarboxylate and ethylene glycol with the same catalysts; (8) ethyl diphenyl-4,41-dicarboxylate and hexamethylene glycol with the same catalysts. Methyl a : d - diphenylbutane - 4,41 - dicarboxylate is obtained by reacting a : d -diphenylbutane with acetyl chloride in presence of AlCl3, oxidising the diacetyl derivatives with sodium hypochlorite to the di-acid and esterifying this. Methyl a : g - diphenylpropane - 4,41 - dicarboxylate is similarly obtained starting from a : g -diphenylpropane.