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:
Dec. 07, 1993
Filed:
Dec. 03, 1992
Yo Iizuka, Iwaki, JP;
Toshio Hosokawa, Iwaki, JP;
Yoshinobu Itoh, Iwaki, JP;
Shinji Yamamoto, Iwaki, JP;
Kazuo Kusida, Iwaki, JP;
Takayuki Katto, Iwaki, JP;
Kureha Kagaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
The present invention discloses a process for producing a granular polyarylene sulfide which has a high melt viscosity and a high degree of cross-linkage, becomes gel under melting and is easy to handle in the production and the fabrication thereof. The process disclosed herein comprises (1) a step (A) an initial-stage polymerization step for obtaining a polyarylene sulfide by reacting an alkali metal sulfide, a dihaloaromatic compound and a polyhaloaromatic compound, having three or more halogen substituents in a molecule, in the presence of water in an amount of 0.5 to 2.9 moles per mol of said alkali metal sulfide at a temperature in the range of 180.degree. to 235.degree. C. until the total conversion ratio of said dihalo- and polyhaloaromatic compounds reaches 50 to 98% and the melt viscosity of a polyarylene sulfide obtained at the end of the step becomes 5 to 5,000 poise, measured at 310.degree. C. and a shear rate of 1,200/second; (2) a step (B) a temperature raising step in which while adjusting an amount of water to be 2.5 to 7 moles per mol of fed alkali metal sulfide, a temperature raising condition from the temperature of step (A) to 240.degree. C. is controlled so that the melt viscosity of a polymer obtained at 240.degree. C. reaches 300 to 10,000 poise, measured at 310.degree. C. and a shear rate of 1,200/second and the temperature raising rate between 240.degree. C. and a temperature of the following step (C) is further controlled to be within the range of 10.degree. to 100.degree. C./hour; and (3) a step (C) a second-stage polymerization step for further continuing the reaction at a temperature of 245.degree. to 290.degree. C. until a melt viscosity of the final product reaches not lower than 1.times.10.sup.5 poise, measured at 330.degree. C. and a shear rate of 2/second. The present invention also discloses a granular cross-linked polyarylene sulfide produced by the process described above.