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. 24, 1998
Filed:
Feb. 11, 1997
Michihisa Miyahara, Wilmington, NC (US);
Hiroyuki Sato, Fukushima-ken, JP;
Yoshikatsu Satake, Fukushima-ken, JP;
Kureha Kagaku Kogyo K.K., Tokyo, JP;
Abstract
The invention provides a process for producing a poly(arylene sulfide) comprising a dehydration step of heating and dehydrating a mixture containing an organic amide solvent (a), an alkali metal sulfide and water to control a water content in the mixture and a subsequent polymerization step of subjecting the alkali metal sulfide and a dihalo-aromatic compound to a polymerization reaction in the organic amide solvent (a), wherein hydrogen sulfide vaporized off during the dehydration step is absorbed in another organic amide solvent (b) outside a system in which the dehydration step is carried out, thereby recovering it, and the hydrogen sulfide thus recovered is reused in the polymerization reaction as a raw material for the alkali metal sulfide. The production process of the invention can solve various problems attendant upon the vaporization of hydrogen sulfide and provide a poly(arylene sulfide) which undergoes little variation in melt viscosity and has stable quality.