| 摘要 |
1,272,800. Porous fibres for use in ultra filtration. RHONE-POULENC S.A. 29 Oct., 1969 [29 Oct., 1968], No. 53077/69. Heading B1X. [Also in Division B5] A tubular fibre containing a continuous hollow channel disposed co-axially or parallel to the axis and having a "skin", in which any pores are less that 500Š in diameter, over its external and/or internal surface, and having in contact with the skin or skins a network of mutually intercommunicating pores of 500Š to 30,000Š diameter and being substantially and preferably entirely free of vacuoles (non- communicating voids), the said network being at least a quarter the thickness of the fibre, the remainder of the fibre if any being different from the vacuole-free network may be made by (a) extruding a fibre-forming polymer solution from an annular orifice spinneret, (b) gelling the external and/or internal peripheral zone and (c) simultaneously or subsequently subjecting one or both of the surfaces whether gelled or non-gelled to the action of a coagulating agent. In the examples the "skin" was from 0.5Á to 100Á thick. The fibre may be a polymer of acrylonitrile (AN), AN/methyl methacrylate (MMA) or particularly AN/ MMA/ potassium p-vinyl oxy benzene sulphonate or a polyurethane or polyvinyl chloride. The tubular fibres according to the invention may be used in reverse osmosis, in separation of gases and in ultra filtration. Thus in the examples nitrogen is transmitted through the fibre wall at internal pressures in excess of 1.5 to 2.5 bars and, a water pressure of 2.0 bars gives a flow rate through the fibre walls of 6 to 55cc/hour/metre of fibre. |
