| 摘要 |
PURPOSE:To form a cylindrical body provided with a heat-retaining foamed layer in a single step, by axially shifting a core die and an outside die, being rotated along the same direction, and synchronizing a foamable material, to be fed into an annular molding space, with the rotating movement of the core die and the outside die. CONSTITUTION:An annular molding space 3 is formed between a radially-rotating axially-moving core die 1 and an outside die 2 provided with a belt 22, helically compactly wound round the inner circumferential surface of a cylindrical body 21 located concentrically with the core die 1, which is cyclically driven in an endless state along the outside of the cylindrical body 21. While the core die 1 and the belt 13, 22 of the outside die 2 are rotated and shifted at the same speed along the same direction, foamable material is concurrently fed into the annular molding space 3. The material is foamed and cured, while being rotated. In this way, a cylindrical body provided with a foamed layer acting as a heat- retaining layer can be produced in a single step. |
