| 摘要 |
1315716 Carbon fibre tapes DEFENCE SECRETARY OF STATE FOR 8 Oct 1971 [15 Oct 1970] 48970/70 Heading C1A Tapes of carbon fibres are made by spreading out a plurality of tows of fibres of a natural or synthetic polymeric material to form a plurality of narrow tapes, juxtaposing the tapes to form a sheet, subjecting the sheet to a preoxidation step in which the fibres of the sheet are held under tension in an oxygen-containing atmosphere at a temperature of about 200‹ C. for up to 7 hours followed by pyrolysis in which the sheet is heated to temperatures in the range of 700-1,500‹ C. and if desired up to 2,500‹ C., in an inert atmosphere, and then dividing the sheet at junctions between at least some pairs of the original narrow tapes thereby forming wide tapes each of which comprises a whole multiple in width of the narrow tapes. The sheet prior to the preoxidation step is preferably cross-stitched. The sheet of carbon fibres prior to division may be impregnated with resin by resin transfer from a coated release paper. Specified polymeric materials are polyacrylonitrile, polyamides and cellulosic compounds. The process may be effected continuously and the specification contains flow diagrams of such a process and also a diagrammatic view of apparatus for splitting the carbon fibre sheet into tapes. |
