Film of good tear property on impact

Claim 1

A biaxially stretched film having an excellent cutting property in the transverse direction, and sufficient break strength in the machine direction to resist breakage by impact in the machine direction, which comprises a mixture of polypropylene and at least one copolymer of ethylene with one or more other copolymerizable ethylenic monomers in a weight ratio of 40 : 60 to 95 : 5, the polypropylene having an isotactic index of not less than 85%, said film satisfying the following requirements: 1. N y -N x = 6 × 10 -3 to 25 × 10 -3 wherein N x is the refractive index in the machine direction and N y is the refractive index in the transverse direction; 2. (N x + N y ) × 0.5-N z ≦ 0.012 wherein N z is the refractive index in the vertical direction and N x and N y are each as defined above; 3. the break elongation in the machine direction = 150 to 800%; and 4. no substantial necking is seen on the surface thereof, said film having been stretched at a draw ratio in the machine direction of from 1.05 to 2.0 and at a draw ratio in the transverse direction of not less than 4.