| 摘要 |
<p>A polyolefin type stretch packaging film, which has at least one layer containing the following component (A), and which has a storage modulus (E') of from 5.0x10<8> dyn/cm<2> to 5.0x10<9> dyn/cm<2> and a loss tangent (tan delta ) of from 0.2 to 0.8, as measured by dynamic viscoelasticity measurement at a frequency of 10 Hz at a temperature of 20 DEG C: (A) a soft polypropylene type resin which satisfies the following conditions (1) to (3), which has a sum of a mesopentad percentage and a racemopentad percentage (mmmm+rrrr) of from 30 to 70% as obtained from <13>C-NMR spectrum, in which crystalline block and non-crystalline block portions co-exist in the molecular chain, and of which the stereoregularity is controlled: (1) the glass transition temperature is at least -15 DEG C as measured by a differential scanning calorimeter by raising the temperature at a heating rate of 10 DEG C/min; (2) the quantity of heat of crystallization is from 10 to 60 J/g as measured by a differential scanning calorimeter by raising the temperature to 200 DEG C after the crystal fusion at a heating rate of 10 DEG C/min, holding the resin at 200 DEG C for 5 minutes, and lowering the temperature to room temperature at a cooling rate of 10 DEG C/min; and (3) the melt flow rate (MFR) is from 0.4 to 40 g/10 min (JIS K 7210, 230 DEG C, 2.16 kg load).</p> |
