| abstract |
(57) [Summary] (Modified) [Constitution] At least the intrinsic viscosity [η] is 5.0 dl / g With the above ultrahigh molecular weight polyolefin A, the stretching ratio in the longitudinal direction after solidification is 3 times or more and the stretching ratio in the transverse direction is 3 times or more, and the breaking strength is 720 kg / cm 2. An ultrahigh molecular weight polyolefin biaxially stretched film characterized by the above. This production method contains an ultrahigh molecular weight polyolefin A and a hydrocarbon-based plasticizer B having a boiling point higher than its melting point, and has a melt flow rate of 0.00. A mixture of 5 to 50 g / 10 min is extruded, and once solidified, at a stretching temperature lower than the melting point of the ultra-high molecular weight polyolefin, the longitudinal stretching ratio is 3 times or more and the transverse stretching ratio is 3 times or more. Stretch. [Effect] It can be used as a reinforcing material by combining with various materials, and those having fine pores can also be used for selective membranes, electrets and the like. |