| 摘要 |
<p>A propylene resin composition is disclosed comprising: a propylene- alpha -olefin random copolymer composed mainly of propylene, the propylene- alpha -olefin random copolymer satisfying the following copolymer property requirements (1) to (4); a nucleating agent which, when added to the propylene- alpha -olefin random copolymer, can bring the isothermal crystallization time ÄBÜ at 115 DEG C of the copolymer to a value satisfying the following requirements ÄIÜ and ÄIIÜ; and 0.01 to 1 parts by weight, based on 100 parts by weight of the propylene- alpha -olefin random copolymer, of spherical magnesium silicate particles having an average particle diameter of 0.5 to 7.0 mu m and a sphericity (f) of not less than 0.7: (i) copolymer property requirements (1) the melt flow rate of 1.0 to 20.0 g/ 10min, (2) the melting peak temperature of 130 to 150 DEG C as determined with a differential scanning calorimeter (DSC), (3) the extraction of not more than 4.0% by weight as measured at 40 DEG C using o-dichlorobenzene as a solvent, and (4) the ratio of the weight average molecular weight to the number average molecular weight of 1.5 to 7.0 as determined by gel permeation chromatography (GPC); and (ii) isothermal crystallization time at 115 DEG C <MATH> <MATH> wherein ÄAÜ represents the isothermal crystallization time (sec) at 115 DEG C of the propylene- alpha -olefin random copolymer with the nucleating agent not added thereto as measured with DSC; and ÄBÜ represents the isothermal crystallization time (sec) at 115 DEG C of the propylene- alpha -olefin random copolymer with the nucleating agent added thereto as measured with DSC. There is also provided a stretched film produced by forming the propylene resin composition into a sheet or a film and at least monoaxially stretching the sheet or film.</p> |
