Method for preparing polyarylene sulfide with reduced free iodine content

Abstract

The present invention relates to a method for preparing polyarylene sulfide with a reduced free iodine content. More specifically, the method for preparing polyarylene sulfide includes: (a) polymerizing reactants including a diiodo aromatic compound and a sulfur compound to form a polyarylene sulfide; and (b) maintaining the polyarylene sulfide product at 100 to 260° C. for heat-setting. The preparation method of the present invention effectively reduces the free iodine content of the polyarylene sulfide to prevent potential corrosion of facilities for the subsequent process and improves the properties of the polyarylene sulfide product such as thermal stability, so the method can be usefully applied to industrial fields in regard to the preparation of polyarylene sulfide.

1 .- 15 . (canceled) 
     
     
         16 . A heat-set polyarylene sulfide having a melting temperature of 265 to 320° C. and a free iodine content of at most 20 ppm,
 wherein the heat-set polyarylene sulfide is prepared by a method comprising: 
 (a) polymerizing reactants including a diiodo aromatic compound, a polymerization inhibitor, and a sulfur compound at an initial temperature of 180° C. to 250° C. and at a final temperature of 270° C. to 350° C. to form a polyarylene sulfide product; and (b) maintaining the polyarylene sulfide product at 150° C. to 230° C. for heat-setting for 0.5 to 100 hours to give the heat-set polyarylene sulfide; 
 wherein the heat-set polyarylene sulfide has a melting temperature variation of less than 5% before and after the heat-setting step (b), and 
 the polymerization inhibitor is at least one of N-cyclohexylbenzothiazole-2-sulfenamide, N,N-dicyclohexyl-2-benzothiazole sulfenamide, tetramethylthiuram mono sulfide, tetramethylthiuram disulfide, zinc dimethyldithiocarbamate, and zinc diethyldithiocarbamate. 
 
     
     
         17 . The heat-set polyarylene sulfide as claimed in  claim 16 , wherein the polyarylene sulfide has a free iodine content of at most 10 ppm. 
     
     
         18 . The heat-set polyarylene sulfide as claimed in  claim 16 , wherein the polyarylene sulfide has a melt viscosity of 200 to 20,000 poise. 
     
     
         19 . A product prepared by molding the heat-set polyarylene sulfide as claimed in  claim 16 . 
     
     
         20 . The product as claimed in  claim 19 , wherein the product is prepared in the form of a molded product, film, sheet, or fabric.