| 摘要 |
PROBLEM TO BE SOLVED: To provide a process for producing a microprorous film free from inorganic filler particles and having high porosity and excellent gas permeability. SOLUTION: A resin composition consisting of a resin component composed of 90-10wt.% of a polypropylene and 10-90wt.% of a polyethylene and 0.01-3 pts.wt. (based on 100 pts.wt. of the resin component) of aβ-crystal nucleation agent is formed in molten state into a film containing the crystalline phase of the polypropylene component in the resin composition essentially in the form ofβ-crystal phase and preferably having a K value of <=0.7. The obtained film is drawn at 60-135 deg.C to obtain the objective microporous film. |
