| 摘要 |
PROBLEM TO BE SOLVED: To provide a cap made of a synthetic resin having excellent gas- barrier properties. SOLUTION: The cap comprises a top plate 3 and a cylindrical part 4 which extends downwards and has on the inner periphery thereof an internal thread part 8 for threaded engagement with a mouth part 2 of a container. A coating layer 12 comprising at least any one of a number of substances such as amorphous carbon, amorphous silicon or silicon dioxide is provided at least one of the inner side and the outer side of the cap 1 made of a synthetic resin. The layer 12 is provided on at least the inner surface side of the plate 3. The layer 12 is provided on the inner surface side of the plate 3, and a seal material layer 13 is provided on the layer 12 or on the inner surface side of the plate 3, and the layer 12 is provided on the layer 13.
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