Patent GB-782947-A (GB)
IPC: D01D5/23
Abstract: 782,947. Production of crimped synthetic filaments. FIRESTONE TIRE & RUBBER CO. July 6, 1955 [July 21, 1954], No. 19516/55. Class 2 (2). Crimped filaments of crystalline synthetic organic linear high polymers are produced by continuously melt spinning a number of filaments of the polymer vertically downwards in a substantially cylindrical or inverted cone array and continuously directing a flow of a cooling gas radially outwardly in all directions from the axis of the cylindrical array past the filaments. As shown in Fig. 2, molten polymer is forced by an extruding machine (not shown) into an extruding head 12 having a distributing passage 14, constituted by a clearance between male and female conical members in the head and leading downwards to the orifices of a spinneret 16. The horizontal face of this spinneret is provided with a number of orifices arranged in a circle coaxial with the spinneret face. The molten polymer is forced through the passage 14 and the spinneret orifices to form a curtain or array of filaments 20 in the shape of an inverted cone coaxial with the spinneret face and perpendicular to this face. Air supplied under pressure by a tube 38 is projected from a jet 32 mounted on a bracket arm 33 attached to the wall of a quenching bath 28 to form a stream 34 which impinges upon a discoidal deflector plate 36 which is attached to and coaxial with the face of the spinneret 16. The stream of air 34 impinging upon the deflector plate 36 is deflected radially outwards as shown by the arrows 30 and flows past the freshly extruded filaments 20. The vibration and non-uniform cooling of the filaments effected by the radial flow of cooling air sets up varying strains along the filaments which are preserved by passage of the filaments through a bath of cooling water 40 in tank 28. The filaments pass under a set of guide pins near the bottom of the bath, upward through and out of the bath, over a guide roll to a pair of draw rolls and a wind-up roll. The filaments are stripped off the wind-up roll and hung up in a loose hank to relax, dry out, and assume a regular crimp. In an example, 92 parts of a copolymer of 85 per cent of vinylidene chloride and 15 per cent of vinyl chloride plasticized with 5 parts of tertiary butyl phenyl salicylate and 2 parts phenoxy propene oxide are extruded vertically downwards at 1010‹ C. through a spinneret having 250 orifices arranged in a circle 6 inches in diameter and 125 cubic feet of free air per minute are directed from a jet # inch from a deflector plate attached to the spinneret face. The filaments are drawn 6 feet through a quenching bath of water at 15‹ C. whose surface is 4 inches below the spinneret. The filaments are stretched to about five times their original length at the spinneret and are then allowed to relax 1 to 24 hours at 25‹ C. for the development of a crimp. High polymers which may be used include polymers of vinylidene chloride and copolymers thereof with up to 20 per cent of vinyl fluoride or acetate, of styrene, esters of acrylic and methacrylic acid such as methyl or ethyl methacrylate, acrylonitrile, of vinyl type ethers and ketones such as methyl vinyl ether, methyl vinyl ketone and isopropenyl ketone; condensation products of dicarboxylic acids with diamines; aromatic polyesters such as condensation products of terephthalic acid and ethylene glycol; polyethylene, and polymers of 2,3-dichlorobutadiene-1,3. U.S.A. Specification-2,451,195 is referred to.