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:
Nov. 17, 1992
Filed:
Aug. 13, 1991
Cherylyn Lee, Fanwood, NJ (US);
Larry F Charbonneau, Mendham, NJ (US);
Gordon W Calundann, North Plainfield, NJ (US);
Hoechst Celanese Corp., Somerville, NJ (US);
Abstract
A process for preparing polyarylates having low color wherein isophthalic acid, terephthalic acid, and bisphenol A are melt polymerized to form a prepolymer, the prepolymer is crystallized, and then further polymerized in the solid state by heating under an inert gas flow, e.g. nitrogen. Crystallization is accomplished by adding the amorphous prepolymer in powder or pellet form to a organic crystallizing medium such as 2-ethoxyethyl acetate or hexyl acetate. This process produces a polymer having low color content. The crystallized polymer may be made amorphous by melting. This amorphous polymer is useful in applications requiring a transparent, colorless plastic.