| 摘要 |
1,182,646. Extruded foamed thermoplastic ribbons. MONSANTO CHEMICALS Ltd. 18 July, 1968 [24 Aug., 1967], No. 39001/67. Addition to 1,114,152. Heading B5A. [Also in Division C3] An extruded foamed thermoplastic material is drawn so that it becomes orientated in one direction to give a product having a width of less than ¢ inch and a thickness less than one quarter of the width. The foamed material may be high density polyethylene, crystalline polypropylene, polyamide, polymethane, poly caprolactam, polyester, e.g. polyethylene terephthalate, or a regenerated natural fibre, e.g. based on cellulose. The drawing operation may be continuous and conducted in more than one stage. In the example a crystalline high density polyethylene containing a green pigment and carbon black was foamed by extrusion using butane as blowing agent and the extruded foam was fed between a pair of rollers and drawn in two stages to produce a flat ribbon containing voids elongated along its length. |
