| 摘要 |
PURPOSE:To avoid an abnormal increase in cap opening torque after sterilization and an abnormal decrease in said torque due to heat history by using as a liner the sealing material of olefin resins having the specific gravity and melt index of a specific value and substantially free from elastomer or lubricant. CONSTITUTION:A cap frame 1 is made by drawing of aluminum, etc., consisting of a top plate 2 and a peripheral side wall 3. A heat sealable coating layer 4 also serving as a protective coating film is formed on the inner surface of the cap frame 1. A sealing material 5 is also provided on the inner surface of the top plate 2 undergoing a process wherein molten resins are extruded in the cap frame 1 and wherein the resulting molded resins are heat sealed firmly to the inner surface of the top plate 2 via the heat sealable coating layer 4. This sealing material 5 consists of the polyethylene having a specific gravity of 0.935-0.970g/cc and a melt index of not more than 15g/10min., containing little elastomer or lubricant. |
