| 摘要 |
PURPOSE:To obtain the subject product having low density and excellent strength, heat-resistance, masking power, writing performance, etc., and useful for label, etc., by extrusion-molding a composition composed of a crystalline polyester resin and a specific hydrogenated polymer and drawing the extrudate under specific condition. CONSTITUTION:An undrawn polyester film is produced by extrusion-molding composition produced by compounding (A) 50-95wt.% of a crystalline polyester resin with (B) 5-50wt.% of a hydrogenated polymer obtained by the hydrogenation of a ring-opened polymer of 100-50mol% of a tetracyclodecene (derivative) unit and 0-50mol% of a norbornene (derivative) unit and having a glass transition temperature higher than that of the component A by >=10 deg.C. The undrawn polyester film is drawn at least in one direction at a temperature higher than the glass-transition temperature and below the crystallization temperature of the component A at a draw ratio of >=1.5 to obtain the objective product having an apparent specific gravity of 0.3-1.3 and containing microscopic voids and the component B dispersed in the polyester film composed of the composition of the components A and B in the form of particles having diameter of 0.1-20mum. |
