| 摘要 |
PURPOSE:To make useful as a material for printing and image formation by molding a compound of a polyester with another thermoplastic resin into sheet, and stretching the sheet in at least one direction to improve strength properties and heat resistance. CONSTITUTION:100pts.wt. polyester contg. pref.>=50 mole% ethylene terephthalate units or 2,6-ethylene naphthalate units is compounded with 5-50pts. wt. thermoplastic resin which is noncompatible with and different from said polyester(e.g., PP) to give a compound. The resulting compound is molded into sheet, stretched in at least one direction at a temp. below the m.p. and pref.10-30 deg.C higher than the glass transition temp. of the polyester in a stretching ratio by area of 4-20, and then heat set at 170-240 deg.C to give a polyester film having a cushon rate of 10-50%, a density of 0.5-1.0gr/cm<3> and a surface roughness of <=2.0mum. |
