| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce a material loss by baking a preform while rotating the preform, and thereby obtaining a block-line molding having an area of a melt viscosity of a specific range and a block deformed amount. SOLUTION: After a polytetrafluoroethylene preform is inserted into a pipe, the pipe is disposed on two rolls. Then, at least one roll is rotated, and the preform is heated and baked while rotating the preform. Thus, the polytetrafluoroethylene preform is obtained. A range of a block deformation amount (%) and a melt viscosity (poise) at 380 deg.C of the obtained block-like molding is a polygonal area surrounded by a straight line A: x=1.0×109 (melt viscosity of 1.0×109 poise), a straight line B: x=2.5×1010 (melt viscosity of 2.5×1010 pose), a straight line C1: y=7.0 (block deformation amount of 7.0%), a straight line D1: y=0 (block deformation amount of 0%) and a straight line E1: y=-8.7 long10 (x)+91.</p> |
