ALEXANDRIA, Va., Dec. 31 -- United States Patent no. 12,509,555, issued on Dec. 30, was assigned to Kureha Corp. (Tokyo).
"Method for producing polyarylene sulfide" was invented by Takeshi Sato (Tokyo) and Yoshinori Suzuki (Tokyo).
According to the abstract* released by the U.S. Patent & Trademark Office: "A method for producing a polyarylene sulfide comprising: initiating a polymerization reaction by heating a mixture containing an organic polar solvent, a sulfur source, water, a polyhaloaromatic compound, and an alkali metal hydroxide in the presence of at least one auxiliary agent selected from the group consisting of carboxylates and the like, to form a reaction mixture containing a prepolymer having a conversion rate of a polyhaloaro...