| 摘要 |
PURPOSE:To continuously obtain a molded article reduced in dynamical anisotropy in low cost by subjecting a polytetrafluoroethylene resin to extrusion molding in the presence of a processing aid using a screw extruder. CONSTITUTION:As polytetrafluoroethylene, not only a homopolymer of tetrafluoroethylene but also one modified by copolymerizing a comonomer in a small amount not reaching a degree imparting melt flowability are contained. As a processing aid, solvent naphtha, white oil, petroleum ether, isopropyl alcohol or the like can be designated and the use amount thereof is set to about 20 - 70 pts.vol. to 100 pts.,vol. of PTFE or a composition of PTFE and a filler. As a screw extruder, both of a single screw extruder and a dual screw extruder can be employed. A full-flighted screw is pref. employed and a screw compression ratio is set to 1.0 - 3.0 and extrusion pressure is set to a range of 5 - 300kg. By this method, a cylindrical, rod-shaped or sheet-like continuous body can be molded. |
