Packaging film for polypropylene resin composition of the heat sterilization food, and packaging films for heat sterilization foods obtained by using the same

摘要

PPROBLEM TO BE SOLVED: To provide the packaging film of a heat-sterilized food, improved in heat resistance, low temperature shock resistance, resistance to bag fracture by dropping, transparency, and moreover, food sanitation and the like, all in a good balance. PSOLUTION: There is provided a propylene resin composition for the packaging film, which is formed of a propylene-ethylene block copolymer obtained by sequentially polymerizing a propylene polymer component (A) in a first step and a propylene-ethylene random copolymer component (B) in a second step, and satisfying the following conditions (i) to (iv). The conditions are: (i) the soluble content of the propylene polymer component (A) at -15°C by TREF (temperature rising elution fractionation) is not more than 0.8 wt.%; (ii) molecular weight distribution of the propylene-ethylene block copolymer ranges from 3.5 to 6.0; (iii) the proportion of the propylene-ethylene random copolymer component (B) to the whole propylene ethylene block copolymer is 10 to 40 wt.%; and (iv) the ethylene content of the copolymer component (B) is 10 to 50 wt.%. PCOPYRIGHT: (C)2011,JPO&INPIT