Patent GB-1088931-A (GB)
Title: Continuous filament nonwoven materials
Inventor: SELWOOD ALAN
IPC: D04H3/147
Filed: 1964-01-10
Abstract: 1,088,931. Fibrous fabrics; treating fibres; yarns. IMPERIAL CHEMICAL INDUSTRIES Ltd. Dec. 29, 1964 [Jan. 10, 1964], No. 1229/64. Headings D1F, D1R and D1W. A non-woven coherent stable web consists of a continuous filament twistless yarn disposed throughout the web in a random loopy configuration, the yam comprising a plurality of intermingled filaments formed from at least one synthetic high molecular weight polymer and exhibiting a pattern of parallelism there-' between, and the filaments being at least partially molecularly oriented and non-crystalline at the time of deposition. The filaments forming the yarn may have a random irregular crimp and preferably have been crystallised and set in the form in which they were deposited. The web may be in the form of a flattened tubular structure. At least some of the filaments preferably are polyamide, for example polyhexamethylene adipamide, filaments. The yarn may contain filaments of different polymeric types to give a heteroyarn. In such a heteroyarn, a minor proportion of the filaments may be potentially adhesive; such filaments may be formed, for example, from polyepsiloncaprolactam, polyaminoundecanoic acid, polyhexamethylene sebacamide or a copolymer (for example an 80/20 copolymer) of polyhexamethylene adipamide and polyepsiloncaprolactam. The filaments in the web may be bonded together by these potentially adhesive filaments. Some of the filaments in the yarn may be heterofilaments, which preferably are potentially crimpable, consisting of at least two different polymer components either in side-by-side or in sheath-core relationship. The heterofilaments may be wholly polyamide and one component may be polyhexamethylene adipamide. The heterofilament may contain a potentially adhesive component, for example polyaminoundecanoic acid, polyhexamethylene sebacamide or a copolymer (for example an 80/20 copolymer) of polyhexamethylene adipamide and polyepsiloncaprolactam. The non-woven web is made by subjecting freshly spun filaments to the action of a high velocity fluid jet acting at an angle to the filament path to provide sufficient tension in the filaments above the point of application of the jet to attenuate and at least partially molecularly orient the filaments, to cause the filaments to intermingle and form a yarn structure exhibiting a pattern of parallelism between the filaments, and to forward the yarn and deposit it on a receiving surface to form a stable coherent web. In the case of polyamide filaments, the filaments may be allowed to crystallise under ambient conditions or gibe caused to crystallise by subjecting the web to a heat or steam treatment. In cases when a proportion of the filaments, or a component of heterofilaments if present, is potentially adhesive, such heat or steam treatment may activate such filaments to bond together the filaments in the web; in the case of heterofilaments, such treatment also may develop the potential crimp in the filaments. The non-woven web may be formed, see Figure III, by passing filaments 21, freshly spun through spinneret 22, through aspirating jet 23 where they are acted upon by high veloscity fluid to form yarn 24 which is forwarded to receiving surface 25 comprising a continuous moving sheet of paper 26 taken from roll 27 on to carrier roll 28. In order that the yarn may be distributed uniformly across the width of the paper, the fluid inlet pipe 29 is moved in a horizontal plane at right angles to the direction of movement of the paper between rods 30 and 31 by means of suitably shaped traversing cam 32 driven by constant speed motor 33. The paper carrying web 34 is collected as a roll 35 which is peripherally driven by rollers 36 and 37 driven by chain 38 operated by motor 39. The aspirating jet, see Figure II, comprises hollow body portion 10 which is externally threaded at either end to receive cover 12 containing yarn inlet guide 13 and cover 14 containing yarn exhaust guide 15. The bottom and top ends of the inlet and exhaust guides respectively are chamfered to provide an annular fluid injector passageway 16, the high velocity fluid, for example air, being supplied via fluid inlet pipe 11. Alternatively, the non-woven web may be formed, see Figure IV, by the use of a rotating exhaust 50 attached to the lower end of aspirating jet 51, the end portion 52 of the exhaust being bent through approximately 40 to direct yarn 53 on to annular receiving plate 54. Rotation of the exhaust causes the yarn to be laid in a random loopy manner around the receiving plate to form tubular web 55 which is withdrawn at constant speed and wound on driven package 56.