| 摘要 |
PURPOSE:To prevent a residue of thermal decomposition of a resin from being stuck on the surface of a torpedo during extrusion and to prevent a vertical flaw from being generated on the inner wall surface of a molded ink-containing pipe by performing a surface treatment for the conical part of the torpedo and the cylindrical part of the tip by a fluoeoresin. CONSTITUTION:A surface treatment (f) of a fluoeoresin is performed in the whole length of the conical part 2b of a torpedo 2 and the cylindrical part 2c of the tip thereof. A residue of resin is easily stuck extremely in the part shown in the shaped portion. On one side, silicon oil Si is sent into a passage 5 of silicon oil and allowed to flow out through an outflow port 6 during extrusion. When resin (r) is extruded by an extrusion screw 4 and passed through the mandrel part 2a of the torpedo 2, silicon oil S1i flows from a boundary part 2d together with resin (r) while covering the surface of the torpedo 2. Resin (r) smoothly flows on the surface of the torpedo 2 by silicon oil Si. |
