| 摘要 |
PURPOSE:To obtain a cap excellent in sealability even when it is used to close a plastic bottle filled with a drink consisting of both a juice component and a gas component by a method wherein a liner is made of a specific polymer composition and the diameter of the pressing part of the liner is made smaller than the inside diameter of a bottle neck part. CONSTITUTION:A mixture of polypropylene resin, hydrogenated block copolymer elastomer, softening material and lubricant is used for use as a polymer composition of which a liner 2 consists and the diameter of the pressing part of the liner 2 is smaller by 1.0-6.0mm than the inside diameter of the neck part of a bottle. A double seam joint is formed between this cap and a plastic bottle filled with the contents containing a carbon dioxide component and a juice component and, when they are treated with heat, the diameter of the upper end of a bottle neck part 3 is reduced. During this time, the liner 2 is pressingly attached to the bottle neck part at a smaller area than the inside diameter of the neck part and the part remaining unpressed is forced inwardly of the bottle. The liner 2 is rigid (stable) due to its polymer composition and the outer part of the pressed part of the liner 2 forced out by the inner peripheral edge of the upper end of the bottle neck part holds down the inner peripheral edge of the upper end of the bottle neck part. |
