Patent ID: 8257822
Filing Date: 2012-09-04
Classification: B32B,C08F,Y10T

Abstract:
1. A film for thermal sterilization packaging characterized by comprising: at least one outer layer containing a propylene/ethylene block copolymer (A) which has a melt flow rate (MFR; ASTM D1238, 230° C., load: 2.16 kg) in the range of 1 to 10 g/10 minutes and a melting point in the range of 150 to 170° C. measured by means of a differential scanning colorimeter (DSC) and which is constituted from 90 to 80% by weight of a part (Dinsol) insoluble in n-decane at room temperature satisfying the following items (1) to (3) and 10 to 20% by weight of a part (Dsol) soluble in n-decane at room temperature satisfying the following items (4) to (6) and at least one intermediate layer or an outer layer containing a propylene/ethylene block copolymer (B) which is not the same as the above propylene/ethylene block copolymer (A): (1) a molecular weight distribution (Mw/Mn) of Dinsol determined by GPC (gel permeation chromatography) is 3.5 or less, (2) a content of a skeleton originating in ethylene in Dinsol is less than 13 mole %, (3) a sum of a 2,1-insertion bond amount and a 1,3-insertion bond amount of propylene in Dinsol is 0.2 mole % or less, (4) a molecular weight distribution (Mw/Mn) of Dsol determined by GPC is 3.5 or less, (5) a limiting viscosity [η] of Dsol in 135° C. decalin is 1.5 to 4.0 dl/g and (6) a content of a skeleton originating in ethylene in Dsol is 15 to 35 mole %.