Meta-xylylene diamine/aliphatic dicarboxylic acid polyamide film

A biaxially drawn film of a polyamide which is produced by subjecting an undrawn film of polyamide to simultaneous or stepwise biaxial drawing at a temperature within a range as calculated according to the following inequality in the case of simultaneous drawing:

• -10W + 120 + 12 log (.delta./1000) >
• T .gtoreq. -6W + 80
• or according to the following inequality in the case of stepwise drawing:
• -10W + 130 + 7 + log (.delta./1000) >
• T .gtoreq. -6W + 80
• wherein the moisture content W is from 0.1 to 5% by weight, the drawing speed .delta. is from 500 to 50,000 %/min in the case of simultaneous drawing and from 500 to 500,000 %/min in the case of stepwise drawing and T is the drawing temperature in .degree. C., said polyamide containing not less than 70 mole % of repeating units of an .alpha.,.omega.-aliphatic dicarboxylic acid having 6 to 10 carbon atoms and metaxylylenediamine or a mixture of metaxylylenediamine and paraxylylenediamine, the amount of paraxylylenediamine present in the polyamide being not more than 30 mole % of the total amount of metaxylylenediamine and paraxylylenediamine, the balance of said polyamide being units of a polyamide-forming monomer copolymerizable with said repeating units and being selected from the group consisting of aliphatic amines, alicyclic diamines, aromatic diamines, aromatic dicarboxylic acids, lactams, .omega.-aminocarboxylic acids and aromatic aminocarboxylic acids, said drawn film having an oxygen permeability coefficient of from 2.6 .times. 10.sup.-13 to 5 .times. 10.sup.-13 ml. cm/cm..sup. 2 sec. cm Hg, a breaking strength of from 14 to 29.8 kg/mm.sup.2, a breaking elongation of from 30 to 150%, a yield strength of from 7 to 13.8 kg/mm.sup.2, a yield elongation of from 2 to 6%, a plane orientation index of from 0.025 to 0.040, and a degree of balance of from 0.003 to 0.045.