PARA-PHENYLENE SULFIDE BLOCK COPOLYMERS, PROCESS FOR THE PRODUCTION OF THE SAME AND USE THEREOF

摘要

Disclosed is a phenylene sulfide block copolymer consisting essentially of a recurring unit (A) and a recurring unit (B) . The recurring units (A) are present in the form of a block of 20 to 5,000 units of (A) on the average in the molecular chain, the mol fraction of the recurring units (A) is in the range of 0.50 to 0.98. The block copolymer has a melt viscosity (?*) of 50 to 100,000 poise as determined at 310.degree.C at a shear rate of 200 sec-1 and has: (a) a glass transition temperature (Tg) of 20 to 80.degree.C, (b) a crystalline melting point (Tm) of 250 to 285.degree.C, and (c) a crystallization index (Ci) of 15 to 45, this value being that of the heattreated, but not stretch-oriented copolymer. Also disclosed is a process for producing the block copolymer comprising a first step of heating an aprotic polar organic solvent containing a m-dihalobenzene and an alkali metal sulfide to form a reaction liquid (E) containing a m-phenylene sulfide polymer of recurring units (B) and a second step of adding a p-dihalo-benzene to the reaction liquid (E) and heating the mixture in the presence of an alkali metal sulfide and an aprotic polar organic solvent to form a block copolymer of the recurring units (B) and recurring units (A) The phenylene sulfide block copolymer may be used for producing molded articles, films, filaments, printed circuit boards etc.