Polypropylene heat-shrinkable film for a resin composition, and a polypropylene heat-shrinkable film using the same and use thereof

摘要

PROBLEM TO BE SOLVED: To provide a heat shrinking film for a PET bottle having a low specific gravity using a small amount of an alicyclic hydrocarbon resin, wherein transparency, gloss and low heat shrinking property are excellent.;SOLUTION: The resin composition comprises (A) 50-95 wt.% of a propylene-ethylene block copolymer and (B) 50-5 wt.% of an alicyclic hydrocarbon resin, and (A) satisfies (A-i) to (A-iii) and (B) satisfies (B-i). In a 1st process, 30-95 wt.% of only propylene or a propylene-ethylene random copolymer ingredient (A1) having ≤7 wt.% ethylene content and in a 2nd process 70-5 wt.% of a propylene-ethylene random copolymer ingredient (A2) containing ethylene in an amount of 3-20 wt.% more than the ingredient (A1) are polymerized step-by-step using a metallocene catalyst (A-i), whereby there is obtained a propylene-ethylene block copolymer having an MFR of 0.1-30 g/10 min. (A-ii) and having a single peak not higher than 0°C in tanδ (A-iii) and having a softening point of 110-160°C (B-i).;COPYRIGHT: (C)2007,JPO&INPIT