| 摘要 |
Plastic, such as polyethylene, is extruded in the form of flat strips from the nozzles incorporated in a block (A). Reinforcing fibres of glass or plastic or metal wire are fed through holes in the block so that they lie between the two strips of plastic. The composite strip is then helically wound around the tube (F) with the edges of adjacent coils overlapping. The plastic strips, whilst they are still hot, are pressed against the tube by a roller (H). Good mechanical resistance is achieved.
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