| 摘要 |
- Process for producing, by extrusion, long straight elements, in which a thermoplastic synthetic material is injected in the viscous or plastic state into an extrusion head provided with an extrusion slot associated with movable blocking-off means capable of interrupting, locally and intermittently, the flow of viscous materials, characterised in that the blocking-off means are controlled so as to create, continuously, in the longitudinal direction of the said element, a substantially solid part and a substantially lacunate part, both parts being contiguous. <IMAGE>
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