| 摘要 |
PROBLEM TO BE SOLVED: To provide a liner resin composition for metallic PP (pilfer-proof) caps which shows good injection moldability, causes no wax floating phenomenon, has thermal resistance and impact resistance enough to endure retort sterilization for 30 minutes at 125°C, causes neither leakage due to thermal shrinkage nor leakage due to a fall, shows good openability, and has a good gas barrier property. SOLUTION: The liner resin composition for metallic PP caps includes: (a) 10 to 30 wt.% of a hydrogenated styrene/isoprene-based elastomer having a melt flow rate (MFR) of 0 under a load of 21.18 N (2.16 kgf) at 230°C (i.e. non-flowable under the condition); (b) 12 to 50 wt.% of a polyisobutylene-based elastomer of a composition obtained by dynamically crosslinking isobutylene-based polymer having an alkenyl group at its end by a hydrosilyl group-containing compound in the presence of a crystalline polypropylene; (c) 10 to 20 wt.% of a polypropylene-based resin; (d) 20 to 40 wt.% of liquid paraffin; and (e) 3 to 15 pts.wt. of a lubricant composed of silicone oil (i) and an amide wax (ii), based on 100 pts.wt. of the sum of (a), (b), (c) and (d). COPYRIGHT: (C)2010,JPO&INPIT |
