Patent GB-547150-A (GB)
Title: Improvements in hosiery and method for producing the same
IPC: D04B1/26
Filed: 1940-10-05
Abstract: 547,150. Artificial filaments ; knitted hosiery; resinous condensation &c. products ; treating textiles &c. with liquids. CARBIDE & CARBON CHEMICALS CORPORATION. Oct. 5, 1940, No. 14920. Convention date, Oct. 27,1939. [Classes 2 (ii), 2 (iii) and 15 (ii)] Textile fibres made from vinyl resins obtainable by the conjoint polymerization of vinyl halides with vinyl esters of aliphatic acids and having an average molecular weight of at least 15,000, are stretched to an extent of about 200- 600 per cent. and then knitted to form hosiery. Hosiery made from these fibres may be formed into any desired shape by a process of controlled shrinkage and this shape is permanent to wear and laundering. The polyvinyl filaments are formed into yarns of the desired size by twisting and doubling. The preferred resins are those containing 70-95 per cent. of vinyl halide. In order that the resins may have an average molecular weight of at least 15,000, they may be subjected to treatment with liquids which extract constituents of low molecular weight. The resins should be soluble in acetone or other liquid in order that a solution suitable for spinning may be formed. Stretching of the yarns may be assisted by heating them, e.g. in the presence of steam. If stretching is carried out at temperatures lower than 100C., the yarns should be subjected to a setting treatment e.g. by prolonged aging of the extended yarns under tension, or by subjecting the stretched yarns to a heat treatment. The yarns may be knitted into flat fabrics of appropriate shape which are subsequently formed into fully fashioned hose by seaming or they may be circularly-knitted to form seamless hose. The stockings may be fashioned permanently by placing them over formers and heating until they shrink and fit the formers closely. Upon cooling, the shape is retained provided that at no subsequent time are the stockings subjected to a temperature in excess of that used in the shrinking operation. Instead of employing heat, the controlled shrinking and forming of the hose may be effected by treating them with a diluted solvent, e.g. acetone and water. Those parts of the stocking which shrink most during the forming treatment may be knitted with a slightly looser stitch so that in the finished article the stitch size will be about uniform. The stockings may be made from yarns containing fibres of natural or regenerated silk or cellulose, or of cellulose derivatives in admixture with the polyvinyl resin fibres. In an example, a polymerized vinyl chloride-vinyl acetate resin of molecular weight 21,000 is formed into filaments which are stretched and gathered into yarns. Lefttwisted yarns are plied with right-twisting to form the knitting yarn. The stockings are knitted on a full-fashioned hosiery machine, thicker yarn being used in the welt and splicing. The foot size is knitted one half size larger than that desired in order to compensate for shrinkage in subsequent operations. The stockings are scoured and dyed at temperatures below 65C. They are then subjected to a forming or boarding treatment at a temperature of 60-70C. Specifications 406,338, 518,555, and 518,710 are referred to.