| 摘要 |
1537466 Injection moulding thermosetting resins SUMITOMO BAKELITE CO Ltd 18 Dec 1975 [21 Dec 1974] 51853/75 Heading B5A An injection moulding device for use with thermosetting resin comprises a screw rotatably located within a barrel, a zone of reduced width between the screw and the barrel being located at the injection end of the device. The width of the zone is from 0À6 to 8 mm. In this zone, the material is subjected to a kneading and shearing action and is brought to the desired temperature, this in turn preventing overheating and perhaps solidification of the material within the barrel proper, and also giving articles of a more uniform nature. The zone of reduced width may be effected either by protuberances on the screw or on the barrel. In a first embodiment (see Fig. 2A) the end of the screw 1 is provided with an enlarged region 4 having two sets of helical grooves 5, 6, one set opening to the front face of the enlarged region and the other set opening to the rear face. In a second embodiment (see Fig. 3A) the enlarged region has a single set of helical grooves 8 running from the rear to the front face. In a variation of this embodiment (see Fig. 6A, not shown) the grooves 8 are of opposite hand to those in the embodiment of Fig. 3A. In a third embodiment (see Fig. 4A, not shown), the enlarged section of the screw has a smooth surface. In a fourth embodiment (see Fig. 5A, not shown) the enlarged section of the screw has a series of cylindrical short protuberances
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