| 摘要 |
PURPOSE:To make it possible to manufacture fuel tank, which is excellent in impact resistance and has high density polyethylene layer having the composition, which is prepared by finely and favorably dispersing polyamide in high density polyethylene, by a method wherein the high density polyethylene and flash and the like of multi-layer plastic fuel tank for reworking are kneaded with and extruder having a screw with specified structure. CONSTITUTION:The mixing ratio of reworked material (which is obtained from some part or the whole of multi-layer plastic fuel tank) to high density polyethylene is normally 20 - 200 pts. wt. of reworked material added to 100 pts. wt. of high density polyethylene. An extruder kneads said mixture at the feed zone 22 of a screw 21 and meters it at the metering zone 23. Further, the extruder performs the lateral mixing of resin flow, which tends to be insufficient at said respective zones, at a cross saw zone 24. In succession, the extruder performs the melting of unmolten resin at the high shearing zone 25. After that, the extruder delivers the resin by mixing longitudinally and laterally. Normally, the length of the screw 21 is set to be length/diameter ratio (L/D) of 20 or more. If L/D is below 20, enough kneading can not be performed. |
