MOLDING OF ULTRA-HIGH-MOLECULAR-WEIGHT POLYETHYLENE PIPE

摘要

PURPOSE:To mold an ultra-high-molecular-weight polyethylene pipe easily by a method wherein the sheet of an ultra-high-molecular-weight polyethylene or a porous sheet is wound around an easily deformable body and is fitted into a mold to heat and adhere the sheet to the mold by the expanding deformation of the easily deformable body. CONSTITUTION:Ultra-high-molecular-weight polyethylene, including the independent polymer of polyethylene and the copolymer of ethylene and the small amount of alpha-olefin or the like, is preferable to have the intrinsic viscosity of 8 or more in the decalin solution of 135 deg.C since resistances to abrasion, shock or the like are prominent in this case. A porous sheet is provided with cavities since a part of it is welded mutually by fusion on the surface of the particles of the ultra-high-molecular-weight polyethylene. An easily deformable body is constituted of a rubber-like substance, a plastic alloy, a shape memory alloy or the like and a non-adhesive substance, such as Teflon, silicone or the like, is interposed between the sheet and the easily deformable body. A pressure is applied on the internal part of the easily deformable body to expand the same. The easily deformable body, wound with an ultra-high-molecular-weight polyethylene sheet 1, is fitted into a predetermined mold 6, the mold is heated to expand the easily deformable body 3 and adhere the sheet 1 to the mold 6 whereby the sheet is molten and densed.