Poly(arylene sulfide) sheet and production process thereof

摘要

A poly(arylene sulfide) sheet excellent in planarity and smoothness is formed of a poly(arylene sulfide) having a melt viscosity, &eegr;* of 1, 000-25,000 poises as measured at 310° C. and a shear rate of 200 sec.sup.-1, and a melt crystallization temperature, Tc.sub.2 or 170. degree.-240° C., wherein Tc.sub.2 is an exothermic peak temperature of crystallization which appears upon the measurement by a differential scanning calorimeter at a cooling rate of 10° C./min after the polymer is heated from 23° C. to 380° C. at a rate of 10° C./min and then held for 3 minutes at 380° C. It has a surface roughness, Ra of 0.09 &mgr;m or less on at least one side thereof and a degree of crystallization of at least 5%. Its number of flexings to break, Y satisfies the following equation (I):P Plog Y≧ 7.11-2.34log t (I)PPwherein t means a thickness (&mgr;m) of the sheet. The sheet is produced by melt-extruding the poly(arylene sulfide) through a slit die into a sheet-like form and then cooling and crystallizing the sheet on a casting roll. The temperature, T (°C.) of the casting roll is controlled to a temperature in a range satisfying the following equation (II):P P120≦T≦190-0.02t (II) PPwherein t means a thickness (&mgr;m) of the sheet, thereby conducting the cooling and the crystallization of the sheet at one stage.