| 摘要 |
PURPOSE:To obtain a plastic pipe showing good and stable property for pressure feeding by constituting the pipe of polyethylene having specified Vicat softening point, density and Olsen rigidity. CONSTITUTION:This plastic pipe consists of polyethylene having 120-140 deg.C Vicat softening point, 0.950-0.970g/cm<3> density, and 7500-13000kg/cm<2> Olsen rigidity. The polyethylene used has small coefft. of friction at normal temp. and showing not so large increase in the coefft. of friction even when temp. is raised. Further the polyethylene has excellent resistance against environmental stress cracking. If one of conditions above described is not satisfied, the effect is not enough. Namely, the coefft. of friction at normal temp. increases and largely depends on temp. and increases with temp. rising. Good and stable pressure feeding property can not be obtd. when the pipe is used for air-blow fiber system. |
