| 摘要 |
PROBLEM TO BE SOLVED: To easily adjust the width of an unstretched sheet without replacing a T-die with respect to the fluctuations of the width of the unstretched sheet due to the fluctuations of conditions. SOLUTION: A thermoplastic resin is extruded from a T-die in a molten state to obtain an unstretched sheet which is, in turn, brought into close contact with a cooling drum to be quenched and, next, both end parts of the unstretched film are grasped by clips and this film is simultaneously biaxially stretched biaxially by 2.0 times or more at stretching temp. of [glass transition point to (m.p. -15)] deg.C to produce a bizalially stretched film. In this method, a seal material is inserted in at least one of end parts of the slit part 2 of the T-die to be melted and extruded. |
