GB1387944A - Textured yarn and method for its manufacture - Google Patents

Abstract

1387944 Knit-deknit crimped yarns ATELIERS ROANNAIS DE CONSTRUCTIONS TEXTILES 28 April 1972 [29 April 1971] 19895/72 Headings D1F D1S and D1W A method of producing a textured yarn comprises knitting an undrawn or partially drawn thermoplastic continuous filament yarn into a tubular knitted fabric, drawing the fabric without breaking the filaments, subjecting the drawn knitted fabric to a further mechanical deformation which is eventually set and deknitting the fabric. The knitted fabric may be drawn longitudinally e.g. between rolls 16, 17 and 18, 19 or transversely e.g. by means of a tenter. The knitted fabric may be subjected to an additional heat treatment preferably during the drawing stage e.g. by means of a steam heated rail 20; or may be heated after drawing to effect an overstretch or relaxation on the fabric. The fabric is preferably subjected to progressive tension between a fabric roll 10, rolls 13, 14 and rolls 16, 17. Prior to or simultaneously with the drawing of the fabric, the yarn may be dyed, e.g. a dye liquor 21 may be placed in the nip of rolls 13, 14. The continuous filaments are suitably polyamide, polyester, polyolefin or polyacrylonitrile filaments. In one example, a fabric is knitted from two feeds of different yarns, the two yarns being deknitted together and forming a composite yarn of low twist. The yarn of the invention is characterised in that the filaments have at least one crimp of serrated type with marked cusps, the molecular structure in the cusps being different from that of the portions of yarn connecting two adjacent cusps, and a secondary crimp superimposed on the serrated type crimp by subjecting the knitted drawn fabric to a passage through a gear-crimping mechanism.