| 摘要 |
PROBLEM TO BE SOLVED: To provide a stretched film which has excellent heat resistance compared with the conventional film, in which stretching unevenness is suppressed even when the stretch ratio is low, and which has excellent mechanical and optical properties after stretching, and to provide a production method of the same.SOLUTION: In a production method of a stretched film, a film including one or more layers composed of a polyolefin-based composition which includes: (a) an olefinic polymer (A) having a melting point (Tm-D), defined by an apex of a peak observed on the highest temperature side of a melting endothermic curve obtained by retaining a sample in nitrogen atmosphere at -10°C for five minutes and subsequently raising the temperature at 10°C/min while using a differential scanning calorimeter (DSC), of higher than 120°C; and (b) an olefinic polymer (B) having a melting endotherm (ΔH-D) obtained from the melting endothermic curve obtained by retaining a sample in nitrogen atmosphere at -10°C for five minutes and subsequently raising the temperature at 10°C/min while using a differential scanning calorimeter (DSC), of 0-80 J/g, and having molecular weight distribution (Mw/Mn) of less than 3.0, in which the content of the component (b) is 0.5 mass% or more and less than 50 mass% based on the sum total content of the component (a) and the component (b) of 100 mass%, is simultaneously or sequentially stretched in biaxial directions with a planar ratio of 45 times or less.SELECTED DRAWING: None |
