| 摘要 |
PROBLEM TO BE SOLVED: To provide an easily openable cap made of a resin which has heat- resistance to withstand a heat-sterilization such as a hot filling, and at the same time, wherein a cap opening torque can be suppressed to a low value by a small using amount of a lubricant, and a combination of sealability, cap opening property and mechanical strength or the like is excellent. SOLUTION: This heat-sterilizable cap made of the resin is formed of a resin composition which contains a propylene based polymer and a high density polyethylene with an amount ratio wherein the high density polyethylene becomes 2 to 10 pts.wt. based on 100 pts.wt. of the propylene copolymer. In this case, for the propylene based polymer, the melt flow rate (at a temperature of 230 deg.C, and a load of 21.18 N) is 3 to 20 g/10 min. For the high density polyethylene, the melt flow rate (at a temperature 190 deg.C, and a load of 21.18 N), is 1 to 20 g/10 min, and the density is 0.940 to 0.970 g/cm3. Also, the resin composition contains the lubricant of 0.3 to 1.0 wt.% per resin.
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