Patent GB-1021762-A (GB)
Title: Improvements in hosiery
IPC: D01F6/66
Filed: 1962-06-20
Abstract: Hosiery is knitted from yarns, e.g. monofilaments, of a synthetic linear polyether which is an oxymethylene polymer. Stable oxymethylene polymers may be prepared by polymerizing formaldehyde or trioxane.  Polymerization of trioxane may take place in the presence of boron trifluoride complexes with organic compounds.  Trioxane may be copolymerized with a cyclic ether having adjacent carbon atoms or with a cyclic ether containing oxy-ethylene groups, e.g. ethylene oxide or 1,3-dioxalane. Thermal stabilizers to an extent of 0.05 to 10% by weight may be added to the polymer, e.g. a combination of an antioxidant and a chain scission inhibitor.  Suitable antioxidants are alkylene bisphenols, e.g. 2,21-methylene bis - (4 - methyl - 6 - tertiary butyl phenol) and 4,41 - butylidene bis - (6 - tertiary butyl-3-methyl phenol) or other phenolic stabilizers such as 2,6-ditertiary-butyl-4-methyl phenol, octyl phenol and p-phenyl phenol. Suitable scission inhibitors are carboxylic amides polyvinyl pyrrollidone, hydrazines, compounds having 1 to 6 amide groups, proteins compounds having amidine groups, cycloaliphatic amine compounds and aliphatic acyl ureas.  The filaments, which may be melt, dry or wet spun, may be drawn preferably while being heated to a temperature of up to 160 DEG C. Preferably, the knitted yarn is between 10 and 35 denier, and has a tenacity greater than 5 gms. per denier and an elongation in excess of 10%.  The stockings may be knitted on a full-fashioned or a circular knitting machine of 30 to 80 gauge.  When knitting the stockings multifilament nylon may be incorporated in the heel, toe and welt.  The stockings may be boarded in dry heat between 130 DEG  and 170 DEG C. as described in Specification 1,016,601 and then dyed at a temperature between 90 DEG and 97 DEG C. for 30 to 120 minutes with dyestuff concentrations between 0.2 and 1.0% by weight. After washing and drying the hosiery is boarded again at a higher temperature.  In an example, a trioxane-ethylene oxide co-polymer (containing 2.5% by weight of ethylene oxide) stabilized with 0.5% by weight of 2,21-methylene-bis(4-methyl-6-tertiar butyl phenol) and 0.1% by weight of cyanoguanidine was melt spun through a spinneret of 0.015 inch diameter, the screw temperature being 190 DEG C. and the spinneret face temperature 178 DEG C. the monofilament was drawn over a shoe heated to 140 DEG C. at a draw ratio of 7.61 : 1 to produce a 20 denier filament.ALSO:Hosiery is knitted from yarns, e.g. monofilaments, of a synthetic linear polyether which is an oxymethylene polymer. Stable oxymethylene polymers may be prepared by polymerising formaldehyde or trioxane.  Polymerisation of trioxane may take place in the presence of boron trifluoride complexes with organic compounds.  Trioxane may be co-polymerised with a cyclic ether having adjacent carbon atoms or with a cyclic ether containing oxy-ethylene groups e.g. ethylene oxide or 1, 3 dioxalane.  The filaments, which may be melt, dry or wet spun, may be drawn, preferably while being heated to a temperature of up to 160 DEG C. Preferably, the knitted yarn is between 10 and 35 denier, e.g. 20, and has a tenacity greater than 5 gms per denier and an elongation in excess of 10%.  The stockings may be knitted on a full fashioned or circular knitting machine of 30 to 80 gauge. When knitting the stockings multifilament nylon may be incorporated in the heel, toe and welt.  The stockings may be boarded in dry heat between 130 DEG C. and 170 DEG C. as described in Specification 1,016,601 and then dyed at a temperature between 90 DEG C. and 97 DEG C. for 30 to 120 minutes with dyestuff concentrations between 0.2 and 1.0% by weight. After washing and drying the hosiery is boarded again at a higher temperature.