| 摘要 |
PURPOSE:To obtain a product whose quality and dimensional accuracy are high and surface is beautiful by a method wherein molding is made possible and neither a sink nor a bubble is generated even if the product is a thick coupling, by forming a hollow member having a lid wall part on an opening part of the coupling by rotational molding. CONSTITUTION:A predetermined quantity of powder of aqueous crosslinking polyethylene to which grafting has been applied is thrown into a revolving mold 2 along with a catalyst appropriately. A rotational mold 2 is heated at about 160-250 deg.C from the outside and rotation of the same is performed in a three-dimensional state for a predetermined period of time. In this instance, the powder is stuck to an inner surface of the rotational mold 2, welded and turned into a surface form corresponding to the inner surface. When a top and bottom forces 2a, 2b are broken after the rotational mold 2 has been cooled through a cooling shower, a hollow member 5 is obtained. When lide wall parts 7, 7 are removed from the hollow member 5 by cutting off the lid wall parts 7, 7 at a chain line with two dots, an ellow type coupling 1 having opening parts 6, 6 at both the ends is obtained.
|
