TITLE: POLY(ARYLENE SULFIDE) SHEET AND PRODUCTION PROCESS THEREOF European Patent Application EP0372829 A3 ABSTRACT: Abstract of EP0372829 A poly(arylene sulfide) sheet excellent in planarity and smoothness is formed of a poly(arylene sulfide) having a melt viscosity, eta * of 1,000-25,000 poises as measured at 310 DEG C and a shear rate of 200 sec<-><1>, and a melt crystallization temperature, Tc2 of 170-240 DEG C, wherein Tc2 is an exothermic peak temperature of crystallization which appears upon the measurement by a differential scanning calorimeter at a cooling rate of 10 DEG C/min after the polymer is heated from 23 DEG C to 380 DEG C at a rate of 10 DEG C/min and then held for 3 minutes at 380 DEG C. It has a surface roughness, Ra of 0.09 mu 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): log Y >/= 7.11 - 2.34log t (I) wherein t means a thickness ( mu 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 ( DEG C) of the casting roll is controlled to a temperature in a range satisfying the following equation (II): 120 <1>, and a melt crystallisation temperature, Tc2 of 170-240 DEG C, wherein Tc2 is an exothermic peak temperature of crystallisation which appears upon the measurement by a differential scanning calorimeter at a cooling rate of 10 DEG C/min after the polymer is heated from 23 DEG C to 380 DEG C at a rate of 10 DEG C/min and then held for 3 minutes at 380 DEG C, characterised in that: (a) the surface roughness, Ra of at least one side of the sheet is 0.09 mu m or less; (b) the degree of crystallisation of the sheet is at least 5%; and (c) the number of flexings to break, Y of the sheet satisfies the following equation (I): log Y >/= 7.11 - 2.34log t (I) wherein t means a thickness ( mu m) of the sheet. 2. The poly(arylene sulfide) sheet as claimed in claim 1, wherein the sheet contains materials extracted by extraction with xylene in an amount of 0.5 wt.% or less of the whole weight before extraction. 3. A sheet for insulating the motor of a coolant-compressor, which comprises the poly(arylene sulfide) sheet as claimed in claim 2. 4. The poly(arylene sulfide) sheet as claimed in any of claims 1 to 3, which has a melt viscosity, eta * of at least 8,000 poises as measured at 310 DEG C and a shear rate of 200 sec<-><1> and has been uniaxially oriented. 5. A process for the production of a poly(arylene sulfide) sheet which comprises melt-extruding a poly(arylene sulfide) through a slit die into a sheet-like form and then cooling and crystallising the sheet on a casting roll, characterised in that: the temeprature, T ( DEG C) of the casting roll is controlled to a temperature in a range satisfying the following equation (II): 120 casting roll is set at 5-300 seconds, thereby conducting the cooling and the crystallisation of the sheet at one stage. 6. The process as claimed in claim 5, wherein the poly(arylene sulfide) has a melt viscosity, eta * of 1,000-25,000 poises as measured at 310 DEG C and a shear rate of 200 sec<-><1>, and a melt crystallisation temperature, Tc2 of 170-240 DEG C, wherein Tc2 is an exothermic peak temperature of crystallisation which appears upon the meausrement by a differential scanning calorimeter at a cooling rate of 10 DEG C/min after the polymer is heated from 23 DEG C to 380 DEG C at a rate of 10 DEG C/min and then held for 3 minutes at 380 DEG C. 7. The process as claimed in claim 5 or claim 6, wherein the poly(arylene sulfide) contains a nucleating agent. 8. The process as claimed in any of claims 5 to 7, which comprises casting the sheet on the casting roll while applying static electricity, thereby causing the sheet to adhere closely to the casting roll. 9. The process as claimed in any of claims 5 to 8, which further comprises subjecting the crystallised sheet to a heat treatment for 0.1-180 minutes at 200-280 DEG C. 10. The process as claimed in any of claims 5 to 9, wherein a polymer obtained by melt-extruding the poly(arylene sulfide) by a vented extrude in advance while drawing a vacuum through a vent port is used as a poly(arylene sulfide). 11. The process as claimed in any of claims 5 to 10, wherein the poly(arylene sulfide) has a melt viscosity, eta * of at least 8,000 poises as measured by 310 DEG C and a shear rate of 200 sec<-><1>, the distance between the tip of the T-die and the upper portion of the casting roll is at most 30mm and the draft ratio is at least 10. DESCRIPTION: When the sheet-like formed product obtained by the bend-processing was used as an sheet-like formed product for insulating a motor of a coolant-compressor, the compressor was able to use for a long period of time without trouble though the motor was a heat build-up type. Example 19: (Bend-Processing of Low-Degree of Crystallization Sheet at Room Temperature) The sheet produced in Example 17 and having a degree of crystallization of 7% and a length of 10 cm was slit into a strip of 85 mm wide. The strip was caused to pass between a pair of rotating metal rolls, which were controlled at room temperature (23 DEG C), while bending it at positions advanced inside by 3 mm from both ends into a U-shape, whereby the strip was bent and its shape was fixed. The clearance between the pair of the metal rolls was about 0.5 mm. It was finely adjusted manually so that sufficient bending and fixing were conducted. The sheet thus obtained was bended and fixed to a sufficient extent. Moreover, no whitening and break were recognized at the bent parts. The sheet hence had sufficient practical utility. Examples 20-21: Using the same resin as that employed in Example 8, which had a melt viscosity of 14,000 poises, casting was conducted by extruding the resin at a delivery rate of 2.0 kg/hour under the same extruding conditions as in Example 8 and controlling the take-up rate. The take-up rate was 1.62 m/min and the thickness of the resulting sheet was 50 mu m. The sheet had a degree of crystallization of 23% and a degree of orientation of 0.75 (Example 20). On the other hand, using the same resin as that employed in Example 1, which had a melt viscosity of 7,300 poises, a sheet of 50 mu m thick was produced at a delivery rate of 2.0 kg/hour and a take-up rate of 2.16 m/min under the same conditions as described above. The thus-obtained sheet had a degree of crystallization of 22% and a degree of orientation of 0.97, which indicated substantially no orientation (Example 21). The drawdown ratios (draft ratios) of these sheet are both 11 because the clearance of the extruder die lip is 0.55 mm. On the other hand, in order to determine the winding tensions of the sheets in the case when the draft ratio was 11 at a melt temperature of 310 DEG C, each of their resins was extruded at a melt temperature of 310 DEG C by a Capillograph through a nozzle of 1.0 mm in diameter and 10 mm in length. At this time, the winding tension of a strand extruded was measured at a draft ratio of 11. In the case of the resin employed in Example 20, the winding tension under the above conditions was 8 g and there was hence a tension of 10 g/mm<2> to the sectional area of the nozzle. In the case of the resin used in Example 21 on the other hand, the winding tension was 1 g and there was hence a tension of 1.3 g/mm<2> to the sectional area of the nozzle. With respect to these sheets, the percent heat shrinkages in both machine and transverse directions were 1.0/0 (MD/TD) in the sheet of Example 20 and 0.5/0 (MD/TD) in the sheet of Example 21. They were hence good in each sheet. The determination of the winding tension to what extent also depends on the properties of a resin to be used and processing conditions. A sheet obtained under conditions of a high winding tension is great in degree of crystalline orientation from its edge face. This makes its elongation at break high in the machine direction (MD). In this invention, the preferred winding tension is at least 2.5 g/mm<2>.