Polyester of para-hydroxy benzoic acid, 1,2-bis(para-carboxyphenoxy)ethane, terephthalic acid and hydroquinone capable of forming an anisotropic melt which readily undergoes melt processing, and molded articles and fibers based thereon

摘要

A polyester is provided which has been found to exhibit an anisotropic melt phase at a temperature which enables it readily to undergo melt processing to form quality fibers, molded articles, etc. The polyester of the present invention is different in character from earlier polyesters and includes as essential ingredients moietiesderived from para-hydroxy benzoic acid 1,2-bis(para- _I carboxyphenoxy) ethane, terephtalic acid, and unsubstituted hydroquinone in certain specified proportions. The polyester of the present invention can be produced on a relatively economical basis and has been found capable of yielding an anisotropic melt of relatively low viscosity at a desirable temperature for melt processing. In a preferred embodiment the polyester is capable of undergoing melt processing at a temperature below approximately 300°C., and in a particularly preferred embodiment at a temperature below approximately 290°C. (e.g. with standard equipment commonly used for the melt processing of polyethylene terephtalate). Fibers conveniently can be melt spun from the polyester of the present invention which exhibit tenacity values which are enhanced to a surprisingly great extent upon thermal treatment.