| 摘要 |
PURPOSE:To make it easy to spirally wind a strip of covering material around the cooled and hardened portion of a plastic pipe by giving twisting rotation to the pipe which is slightly heated and softened. CONSTITUTION:A covering material 6 is composed of a base material 61, an expansion layer 62, a protective film layer 63 and an adhesive layer 64 which adheres to a tubular element 2. The base material 61 is composed of flexible thin film, netlike element of non-expansive and non-inflammable materials such as metal, glass, carbon, ceramic, etc. and unwoven matter of these fibers and mesh woven cloth, etc. The expansive layer 62 is composed of expansive agents which emit gases such as water, carbonic acid gas, nitrogen gas, etc. by being exposed and decomposed by high temperature such as water glass, metallic salt, organic foaming agent, etc., a synthetic resin as a binder agent, other filler materials, and additives such as age-resistor, ultra violet rays absorbing agent, etc. Next, he protective film 63 layer is composed of a plastic film which does not permeate moisture and gases. When the portion of a covering construction element 8 outside a wall 7 is exposed to high temperature, the expansion layer 63 expands, but its expansion in the direction of outer circumference is restricted by the base material 61 and it expands in the direction where it crushes the tubular element 2. |
