| 摘要 |
PURPOSE:To obtain a tubular body having a smooth surface and little heat shrinking property by coating the inwall surface of a mold with a polytetrafluoroethylene dispersion, heating the inwall surface at a temperature higher than the melting point of polytetrafluoroethylene and forming the tubular body on the inwall surface of the mold. CONSTITUTION:The wall surface of the cylindrical section of a mold is coated with a polytetrafluoroethylene(PTFE) dispersion, and the wall surface is heated at a temperature higher than the melting point of PTFE. A dispersion medium in the dispersion applied on the mold is evaporated and removed by the heating, and a PTFE tubular body is formed on a coated surface. Consequently, the PTFE tubular body obtained has the excellent smoothness of a surface while heat shrinkage factors in the longitudinal direction and the circumferential direction at the temperature higher than the melting point of PTFE are brought to 5% or less. The coating of the PTFE dispersion to the mold and heating at a temperature less than the melting point of PTFE are repeated, thus adjusting the wall thickness of the tubular body. |
