| 摘要 |
PURPOSE:To overcome disadvantages such as shrinkage in its width direction or the occurrence of creases by specifying the drawing magnification in the longitudinal direction, the temperature of a low speed roll for drawing, and the expansion and contraction rate when immersed in high temperature water, in the case of manufacturing a thermal contraction film. CONSTITUTION:Vinyl chloride resin is extruded from a mouthpiece 1 in a heat fluid state and then cooled by a cooling drum 2 so as to be made into a film 3, subsequently, it is delivered to a low speed roll 8 by means of guide rolls 4, 5 and, next, drawn in the longitudinal direction by means of a high speed roll 9 for drawing, furthermore, guided by means of guide rolls 6, 7 in order to be made into an article. The film 3 is drawn 1.7-2.7 times in the longitudinal direction by the agency of the difference of circumferential speeds between the low speed roll 8 and the high speed roll 9. At this time, the temperature of the low speed roll 8 is allowed to be in the range of higher at 15-30 deg.C than the softening temperature of film resin to be treated. The thermal contraction film obtained in this fashion is of the type wherein the expansion and contraction rate thereof is -35 to -55% in the longitudinal direction and +5 to +15% in the width direction. |
