| 摘要 |
PURPOSE:To obtain a highly toughened film, by melting and extruding a copolymer of 1-butene and ethylene and having a density of 0.915-0.940g/cm<3>, and stretching the resulting film laterally by a stretching factor of 2 or more at 70 to 110 deg.C. CONSTITUTION:A copolymer of ethylene and 1-butene and having a density of 0.915-0.940g/cm<3> is melted and extruded using a T-die filming apparatus or an inflation filming apparatus into an unstretched film. Then the unstretched film is stretched laterally at a draw ratio of 2 or more at 70 to 110 deg.C to obtain the intended highly toughened film. It is preferable that at the melt extrusion the resin temperature is 150-250 deg.C and the draft ratio is 18 or over. In case the unstretched film is tubular, a tubular horizontal stretching apparatus can be used while in case it is flat, a usual tenter can be used. |
