MANUFACTURE OF BIAXIALLY STRETCHED POLY-EPSILON-CAPROAMIDE FILM

摘要

PURPOSE:To obtain a biaxially stretched poly-epsilon-caproamide film for packing, having laser plasticizer content and free of blocking, by a method in whch poly-epsilon-caproamide film is biaxially stretched under a specific condition by a combination of roll-type longitudinal stretching mode and tenter-type lateral stretching mode. CONSTITUTION:An amorphous and non-oriented poly-epsilon-caproamide film is heated at 45-65 deg.C and longitudinally stretched 2.7-3.5 times at deforming rate of 5,000%/min or more by a roll-type longitudinal stretching mode. The longitudinally stretched film 1 is soon adjusted to 45-60 deg.C is sent to a lateral stretching start position A during the time period of the formula I [where (t) is the time (second) from the ending of longitudinal stretching to the beginning of lateral stretching and T1 is temperature of film] and immediately before the operation is locally heated within one second at the temperature of the formula II (where T2 is the temperature of film at the local heating point) by a heater. The film is then stepwise heated by regulating the tenter clip temperature T3 of the lateral stretching start position A to T3