| 摘要 |
<p>1367880 Reinforced plastics tube BTR INDUSTRIES Ltd 1 Sept 1971 [11 Sept 1970] 43611/70 Heading F2P [Also in Division B5] An extruded tube 40 of thermoplastic, thermosetting, or rubber material, comprises inner 41 and outer 42 layers of the same or different material and each of which includes discrete staple fibres which have been oriented, during extrusion, along a helical path of opposite band to the fibres of the other layer. The helix angles may be 50 to 60 degrees, and is preferably 54‹44<SP>1</SP>. The fibres are of a length preferably 400 times their diameter. The tube may include a further layer of different material on its inner and/or outer surface. The helix angle of each layer may be the same. The helical orientation is obtained by extruding through die parts which rotate in opposite directions (see Division B4-B5).</p> |
