| 摘要 |
PURPOSE: To provide a film having a low coefficient of friction and improved in wearing resistance and handleability by extruding a thermoplastic resin containing inert particles into a sheet and biaxially stretching the sheet. CONSTITUTION: A thermoplastic resin (a) is melt-kneaded together with 0.001-0.3wt.% spherical inert particles having an average particle diameter of 5-2,000nm, an aspect ratio of 1.0-1.3, and a relative standard deviation of 0.6 or lower. The mixture is extruded into pellets containing the inert particles. These pellets are melted at a temp. not lower than the m.p. of the resin (a) but not higher than the decomposition point thereof, and are extruded into a sheet together with a thermoplastic resin not containing inert particles to obtain an unstretched film. This film is stretched in an areal stretch ratio of 9 or higher and then heated at 140-280 deg.C for 0.5-60sec. Thus, the objective film is obtained in which the average height of surface projections on at least one side is 10nm or larger and is 1/4 to 1/3 of the average particle diameter (b) of the inert particles and the number of projections having a height not higher than 1/3 of the diameter (b) accounts for 40-80% of the total number of all projections. |
