Patent GB-1190639-A (GB)
Title: Filamentary Materials and Fibrous Products.
Inventor: WAGNER WILLIAM SHERWOOD
IPC: D04H3/16
Filed: 1967-09-29
Abstract: 1,190,639. Filamentary structures. CELANESE CORP. 29 Sept., 1967, No. 44393/67. Heading B5B. [Also in Division D1] A process for the production of a body of entangled filamentary material comprises extruding a molten organic filament forming material through an orifice into a zone in which the molten material solidifies into a substantially continuous filament and attenuating the extrudate before it solidifies by the action of a plurality of high velocity gas or vapour streams flowing through passages arranged to direct the streams towards without intersecting the extrusion axis which forms, with the projection of each passage axis on the plane which includes the extrusion axis and the point on the passage axis at the passage outlet, an angle of 3 to 15 degrees. Three or more of said gas or vapour streams may be directed through passages arranged symmetrically about the axis of extrusion, so as to provide a skew angle of from 1 to 10 degrees. Preferably, the passages provide a convergence angle of 4 to 7 degrees and a skew angle of 1 to 7 degrees. The body of entangled filamentary material is suitably collected on a surface arranged close enough to the extrusion orifice for the collected material to be in a partly solidified ahesive condition, and is suitably removed from the zone in which it is formed by contact with one or more moving surfaces. Especially, the entangled filamentary material is removed from the zone in which it is formed by contact between opposite faces of the body and a pair of moving endless surfaces spaced apart to permit the filamentary material between said opposite faces to pass therebetween. After such removal the entangled filamentary material may be continuously severed across its width in a direction parallel to the extrusion direction through material which has not contacted the moving surfaces. Specified fibre-forming materials include polyolefins, polyamides, polyesters, cellulose acetate, polyvinyl acetate, polymethyl methacrylate and styrene copolymers. Apparatus as shown comprises a nozzle 4 having, extending to the face of the nozzle, a passageway 24 terminating with a filament extrusion orifice 26 and three or more bores 28 terminating symmetrically around said orifice, said bores being arranged to provide a convergence angle of 3 to 15 degrees, means being provided for supplying molten organic filament-forming material to said passageway and gas or vapour under pressure to said bores. Desirably, the axis of each of said bores 28 converges on the extrusion axis and is arranged to provide a convergence angle of from 3 to 15 degrees and a skew angle of from 1 to 10 degrees. In Fig. 1, the filament-forming material is heated in an extruder 2, and extruded through nozzle 4, steam or other heated gas being supplied thereto through lines 6, and is directed outwardly from the nozzle to surround the filament 8 issuing therefrom. Filament 8 is projected by the gas to the surface of a rotating collecting drum 10, and as filament 8 may not be completely solidified when it reaches the drum points of intersection of the filament are joined together by self-bonding to form a mat 12. The product 12 may be used as such, or may be treated as, e.g. by calendering, needling, compressing, impregnation with latex or other filler, or embossing to form various structures, As in Figs. 6 and 9 (not shown) preferred apparatus comprises a pair of driven rollers or endless bands spaced apart from each other and arranged to carry away filamentary material, which is extruded through the orifice and formed into a tangled body by gas or vapour from the bore outlets, through the space between the rollers or bands by contact between the surfaces of the rollers or bands and the outer filamentary material of said tangled body. Thus in Fig. 6, where the material is collected between rollers (104), (106), the product (110) has a distinctive structure including upper and lower surface layers (114) spaced apart by an integrally formed core (115). On the outer surfaces the filamentary material is predominantly in planes parallel to the surface, and said outer layers are united by filamentary connections between the layers forming the inner layer (115) which is thicker and of lower apparent density than the outer layers. The predominant orientation of these filaments is at an angle to the faces of the product. The inner layers may be in the form of webs separated from each other by zones substantially free from filamentary material. In Fig. 9, the product is collected between the endless belts (134), (142) and may be slit at (152) to provide a product resembling a pile carpet. Laminated products may be formed by collecting the filamentary material upon sheets or webs passed over one or both of the endless belts and causing the filamentary material to adhere thereto, as by heating or bonding treatments. In a further modification, a plurality of spraying nozzles in a row is used. In Fig. 10 (not shown), the nozzle (160) is directed at the gap between a pair of rolls (158), as in Fig. 6, but means are provided for traversing the rolls along the frame (166) during spraying. The product so obtained is characterized by containing a series of sheet-like fibrous subassemblies (184), each generally U-shaped, as in Fig. 11 (not shown), and within each sheet the filament is randomly arrayed in the sense that, if the U- shaped subassembly were flattened into a plane, incremental portions of the filament would be found extending in substantially all directions within that plane. At the end of one traversing motion and the beginning of the next, only a single body of filamentary material is collected, so that successive layers of the subassemblies (184) are united at the lateral margins of the fabric.