| 摘要 |
PURPOSE:To make polyethylene terephthalate resin into a film efficiently, by performing inflation molding of the polyethylene terephthalate resin of a specific value or higher at a specific extrusion temperature. CONSTITUTION:Polybutylene terephthalate resin whose intrinsic viscosity is 1.0 or higher is melted and discharged through an annular mouthpiece by an inflation method. In this instance, a temperature of the resin is made to fall within a range of melting point ( deg.C)<extrusion resin temperature ( deg.C)<melting point -26 +53 X intrinsic viscosity deg.C. The range of the resin temperature in the inflation molding is shown by oblique lines in the figure. When the resin temperature is too high, film making is difficult due to drawdown. When the temp is too low, on the contrary, melt viscosity is increased, productivity is lowered and uneven thickness of the film is increased. |
