| 摘要 |
PURPOSE:To improve the creep resistance and the impact resistance of fiber reinforced plastic by a method wherein molten thermoplastic resin and long fiber bundle are extruded simultaneously and, just after their extrusion, the resin-covered fiber bundle is rolled with hot rolls. CONSTITUTION:A resin such as polypropylene or the like is charged to an extruder 1. The resin is extruded from the extruder and sent to a die 3 having L/D of 100-300. On the other hand, eight long fiber bundles made of glass filament or the like is charged from a fiber bundle feeding device 10 to the die 3 in the form of small fiber bundle so as to be pulled out in the form of long fiber-molten resin strand 2 simultaneously together with molten resin. The resultant strand 2 is heated with heating rolls consisting of fixed rolls 5 and 6 and a free roll 4, which are provided near the die 3, up to 160-250 deg.C. in this case, the linear pressure of the free roll is controlled to be 5-20kgf/cm to the total of the eight bundles. By passing the strand 2 through the rolls, the rolling of the strand is performed. The strand after being rolled is passed through a sizer 11, which is heated up to the melting temperature of the resin or higher, so as to be turned in strand having circular crosssection. After that, the resultant circular strand is passed through a cooling water tank 7 so as to cool and harden the resin. Finally, the hardened strand is taken up with a take-up machine and cut in arbitrary lengths with a cutter 9. |
