VERFAHREN ZUR HERSTELLUNG VON BIAXIAL GERECKTEN FOLIEN AUS POLYAMIDGEMISCHEN

摘要

A process for preparing a biaxially stretched film of a polyamide blend, which comprises (1) melt extruding a polyamide blend to make an unstretched film and (2) stretching the unstretched film first in the machine direction and then in the transverse direction, or (2') stretching the unstretched film first to make a uniaxially stretched film having a plane orientation index of about 0.6 to 1.7 and then stretching the uniaxially stretched film in a direction substantially at a right angle to the direction at the previous stretching, said polyamide blend comprising 97 to 80% by weight of an alpha -type aliphatic polyamide (Component A) and 3 to 20% by weight of at least one polyamide (Component B) selected from the group consisting of (i) an alpha -type aliphatic polyamide different from the Component A, (ii) a gamma -type aliphatic polyamide, (iii) a non-crystalline aliphatic polyamide, and (iv) a ring-containing polyamide which contains in the molecule 0 to 50 mol % of repeating units comprising a xylylenediamine residue.