| 摘要 |
<p>PURPOSE:To suitably use a duplex tube as a piping material for fluid such as pure or superpure water by forming an inner layer of poliphenylensulfide resin layer and an outer layer of chlorination vinyl chloride. CONSTITUTION:An outer layer 1 is formed of chlorination vivyl chloride resin, and an inner layer 2 is formed of normal chain type poliphenylensulfide. The poliphenylensulficle resin layer forming the inner layer 2 is extended to fold back an right end part 21, or only the outer layer 1 at the tube end is cut and removed to fold back the inner layer 2. In the case where a tube end is protected by the poliphenylensulfide resin, and a duplex tube is connected by butt thermal welding method, since the chlorination viyyl chloride resin forming the outer layer 1 does not protrude inside the tube in the form of a bead, this welding method is desirable. Thus since the outer layer 1 displays heat resistance and high rigidity, and the inner layer 2 checks the elution of organic substance and metallic ion, the duplex tube can be suitably used as a piping material for pure and superpure water.</p> |
