| 摘要 |
PROBLEM TO BE SOLVED: To provide a high durability bellows (and an industrial manufacturing method thereof) for remarkably improving durability in a product bellows (B) manufactured by performing cutting work on its compressive mold (M) by reforming "quality" itself of the cylindrical compressive mold (M) provided to the cutting work.SOLUTION: This bellows (B) is formed by performing machining cutting work on the medium or large cylindrical compressive mold (M) made of a polytetrafluoroethylene resin, and is characterized in that assuming respectively crystalinity of an inner diameter part (1a) and an outer diameter part (1b) of a bellows forming part (1) of its bellows (B) as (a and b), (a) is 55 or less and (b) is 56 or less. |
