Patent GB-1016862-A (GB)
Title: Improvements in or relating to textile fabrics
IPC: D04H1/42
Filed: 1962-06-20
Abstract: 1,016,862. Finishing fabrics. E. I DU PONT DE NEMOURS & CO. June 20, 1962 [June 20,1961], No. 23767/62. Heading D1S. A fabric comprising a plurality of composite filaments each comprising at least two different synthetic polymeric components having different shrinkage characteristics and each of which is present in the filament as one or more longitudinally extending segments in substantially sideby-side relationship with at least one segment of another component, is heated at an elevated temperature such that the segments of different components are shrunk to different degrees and simultaneously or subsequently subjecting it to a flexing action sufficient to separate the segments and to entangle or interengage the separated segments. Preferably the fabric is contacted by a hot aqueous liquid which is subjected to agitation or turbulence to cause the filaments to flex. The liquid may contain a swelling agent, a soap or detergent or an emulsified solvent, e.g. to remove sizing. Preferably one of the synthetic polymeric components S, Fig. 5, shrinks to a substantially greater degree than the second component F when subjected to treatment with hot or boiling water, but to a substantially lesser degree than the component F when heated to a higher temperature below the softening point of the lower melting polymer. After treating with hot aqueous liquid and flexing so that filaments of the component F having a greater extended length than the filaments of the component S at forced into positions at or near the fabric surface, see Fig. 5. The fabric is then dried and heated to a temperature, e.g. above 100C. so that the filaments of the component S are brought to or near the fabric surface and a significant number of filaments of the component F move into the fabric interior, Fig. 6 (not shown). The denier of the component S is preferably lower than that of the component F and may be between 0.1 and 1. 8. The yarn segments of at least one component preferably have a longitudinally extending sharp edge configuration formed in part or wholly by a surface(s) in contact with another segment(s). The composite filaments may have a trilobal cross section as shown in Fig. 12 or as described in U.S.A. Specification No. 2,939,201 or a tetrilobal cross-section. The yarns may be heat relaxed before being knitted or woven into the fabric. Polymers used include polyamides, polysulphonamides, polyesters, polyurethanes, polyureas, polymers of cellulose esters and cellulose ethers, polyethylene, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, and polymers disclosed in Specifications Nos. 597,368 and 586,881 and U.S.A. Specifications Nos. 2,601,256 and 2,527,300. The preferred group of polymides comprises polyhexamethylene adipamide, polyhexamethylene sebacamide, polyepsilon caproamide copolymers thereof. Polyesters include polyethlene terephthalate and corresponding copolymers containing sebacic acid, adipic acid and isophthalic acid and polyesters containing recurring units derived from glycols with more than two carbons in the chain e.g. diethyl glycol, butylene glycol, decamethylene glycol and (rans-bis-1, 4- (hydroxy methyl)-cyclohexane. In one example that hot aqueous contains a petroluem distillate, and alkyl-aryl polyester alcohol emulsifying agent and trisodium phosphate and in another example the liquid contains a non ionic surfactant, an anionic hydrocarbon sodium sulphonate softener and sodium o-phenylophenate.