| 摘要 |
Disclosed is a heat-shrinkable biaxially drawn polyamide film which is formed from a homopolymer or copolymer of epsilon -caprolactam or a polyblend thereof, by a sequential biaxial drawing method and which has a density of 1.129 to 1.136 g/cm<3> and an in-plane orientation index of 0.0535 to 0.0580. This film is prepared by the steps of drawing in the machine direction a substantially amorphous unoriented polyamide film at 45 to 65 DEG C, a deformation rate of at least 10,000%/min and a draw ratio of 2.7 to 3.5 by a roll type longitudinal drawing method, gripping the ends of the film by tenter clips, drawing the film in the transverse direction at a film temperature not higher than 100 DEG C, an average deformation rate of 2,000 to 10,000%/min and a draw ratio of 3 to 5, and heat-treating the film at 125 to 170 DEG C while gripping the ends of the film by the tenter clips. |
