| abstract |
A process for preparing a biaxially stretched film of polyamide blend, which comprises (1) extruding a polyamide blend in melt to make an unstretched film and (2) stretching the unstretched film first in a machine direction with a stretch speed of about 40,000 to 60,000,000 %/minute in a draw ratio of about 2 to 6 and then in a transverse direction with a stretch speed of about 500 to 100,000 %/minute in a draw ratio of about 2 to 6, or (2') stretching the unstretched film first to make a uniaxially stretched film having a plane orientation index of about 0.6 to 1.5 and then stretching the uniaxially stretched film in a direction being substantially at a right angle to the direction at the previous stretching, said polyamide blend comprising an aliphatic polyamide and a polyamide containing in the molecule at least about 70 mol % of the repeating units constituted with metaxylylenediamine or its mixture with paraxylylenediamine (of which the content is not more than about 30 mol % based on the combined amount of metaxylylenediamine and paraxylylenediamine) and at least one α,ω-aliphatic dicarboxylic acid having 6 to 10 carbon atoms in a proportion of about 97 : 3 to 80 : 20 by weight. |