PRODUCTION OF POLYAMIDE FILM

摘要

PURPOSE:To produce a polyamide film uniform in physical properties by reducing a bowing phenomenon. CONSTITUTION:A polyamide film stretched at least in a lateral direction is subjected to first stage thermal fixing while relaxed or stretched within a range of 10% or less at temp. equal to or lower than the m.p. of polyamide by a tenter and subsequently subjected to second stage thermal fixing while relaxed or stretched within a range of 10% or less at the max. temp. within the temp. range from stretching temp. to the m.p. of polyamide by a multistage roll in such a state that the temp. of a rear stage roller is made higher than that of a front stage roller. After lateral stretching performed before the first stage thermal fixing, a cooling process satisfying formula L/W>=1.0 [wherein L is the length (m) of the cooling process and W is the width (m) of the film] is provided to cool the film to the glass transition point of polyamide or lower.