The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 01, 1977
Filed:
Jun. 05, 1974
Erich Behr, Troisdorf, DT;
Wolfgang Wolfes, Bergheim, Sieg, DT;
Dynamit Nobel Aktiengesellschaft, Troisdorf, DT;
Abstract
A process for the preparation of a thermostable polyester which is insoluble in tetrachloroethane and consists of about 40 to 200 units, said polyester having units of the formula ##STR1## combined with units of the formula ##STR2## wherein Ph is ##STR3## AND BOTH R radicals are methyl on some units and both R radicals are phenyl on the balance of the units, said methyl units comprising 5-30 mole percent of the total R-containing units which comprises heating and condensing in the absence of a catalyst 4,4'-dihydroxytetraphenylmethane having a melting point of at least 295.degree. C together with 2,2-bis-(4-hydroxyphenyl)-propane and terephthalic or isophthalic acid dichloride until there is prepared said polyester which is insoluble in tetrachlorethane.