Patent GB-1166071-A (GB)
Title: Filamentous Product and Method and Apparatus for Making Such Product
IPC: A24D3/02
Filed: 1966-09-15
Abstract: 1,166,071. Spinning apparatus. EASTMAN KODAK CO. 15 Sept., 1966 [15 Sept., 1965], No. 41184/66. Heading B5B. [Also in Division A2] An apparatus for forming a filamentous product having an inner core of filaments 58 in which the molecules thereof are substantially free of orientation along the axis of the filaments and an outer layer of filaments 56 in which the molecules thereof are arranged substantially along the axis of the filaments comprises a spinning cabinet 12, spinneret means 16 mounted within the spinning cabinet and having a central group of orifices 26 surrounded by an outer group of orifices 24, first conduit means 30 connected to the central group of orifices for supplying a spinning solution thereto under relatively high pressure, second conduit means 28 connected to the outer group of orifices for supplying a spinning solution thereto under relatively low pressure, and collecting means 40 positioned for taking-up the filaments so produced, the collecting means being adapted to withdraw the spun filaments from the spinning cabinet at such a rate of speed as to maintain a constant draw tension on the filaments being spun by the outer group of orifices by permitting the filaments being spun by the central group of orifices to fall under substantially their own weight. As shown, the first and second conduit means 30, 28 include fluid pumps 36, 34 for adjusting the pressure of the spinning solution being supplied to the spinneret means in accordance with the operating speed of the collecting means. In operation, an inner core of free-fall spun filaments is formed surrounded by an outer layer of draw-spun sheath filaments, the filaments are associated into a common bundle while they are still wet, and the sheath filaments are subjected to a longitudinal tension while the bundle is drying thereby producing a selfsustaining filamentous product having a core of irregular shaped filaments surrounded by a sheath of substantially smooth surface filaments. Suitably, the spinning solutions are of thermoplastic organic solvent-soluble materials, for example cellulose acetate, and the two solutions may be the same or different. The solution forming the sheath filaments is preferably extruded at a higher jet velocity than the solution forming the core filaments. To expedite the curing of the wet filamentous product as it leaves the spinneret head and moves through the spinning cabinet 10 towards opening 38, a curing gas is forced into the spinning cabinet through inlet conduit 42 and withdrawn from the cabinet by outlet conduit 44. The filamentous product which may be randomly bonded together at the point where the fibres touch so that the draw-spun and free-spun fibres are " integral " parts, is further gathered together at the lower end of the spinning cabinet 12 and passes through opening 38 onto the take-up roller 40. From roller 40 the combination filamentous product 46 is moved by conveyer 48 through a drying apparatus 50, if such is required, and is packed as a baled product 62 by a baler unit 54. If desired, a plasticizer may be used to bond the product (Example 5).