Patent GB-560084-A (GB)
Title: Improvements in or relating to the production of knitted fabrics from synthetic linear polyamide yarns
IPC: D06M15/17
Filed: 1942-05-26
Abstract: Sheer knit goods, substantially free from snags and pulled threads, are obtained from water-insensitive, continuous filament, synthetic linear polyamide yarns, by applying to the yarns, as a snag-proofing composition, an aqueous liquid comprising a film-forming substance which is tacky in the air-dried state and which is dispersible in an aqueous liquid, and then knitting the treated yarns.  Yarns so treated have good running properties on full-fashioned knitting machines, and the composition deposited on the yarns prevents serious edge rolling of the stocking fabric. The composition may readily be removed from the fabric after the completion of the stocking, by means of an aqueous boil-off bath. Tackiness of the film-forming composition is tested by dropping a standard lead shot on to a film of the composition under specified conditions, inverting the film and noting whether the shot is retained after 5 seconds.  The film-forming substance may be an alkyd resin, a vinyl interpolymer, a natural resin, or a carbohydrate, e.g. a mannitol maleate or phthalate or a sorbitol citrate or phthalate of high acid number; a reaction product of rosin and maleic anhydride or of a terpene and maleic anhydride; a completely or partially hydrolyzed copolymer of ethylene or other olefine and maleic anhydride; pine rosin or a water-soluble salt thereof; a non-crystallizing sugar syrup such as honey or corn syrup; a highly plasticized glycerol phthalate of high acid number; a plasticized resin obtained from methyl methacrylate and methacrylic acid in presence of a peroxide catalyst. Plasticizers may be incorporated in the composition in order to render the film-forming substance sufficiently tacky in air-dried condition. The plasticizer may be, in the case of an alkyd resin or polyvinyl resin, glycerol, sorbitol, diacetin, triethylene glycol, polymerized ethylene oxide, triethanolamine oleate, or N-(b -hydroxyethyl) formamide, these being water-soluble, or di(b -methoxyethyl) adipate, dibutyl phthalate, or tributyl phosphate, these being insoluble in water.  To render acidic resinous materials soluble in aqueous solution, they may be treated with dilute alkalies.  The synthetic linear polyamide of which the yarns are composed may be polyhexamethylene adipamide. In an example, a polyamide yarn is impregnated with an aqueous solution containing ethanol, and the neutral ammonium salt of a resin obtained by heating diethylene glycol and the maleic anhydride adduct of a terpene fraction consisting essentially of a -terpinene.  The yarn is dried and then knit in wet condition. A polyamide yarn is treated with an aqueous solution containing ethanol, dibutyl phthalate, polymerised ethylene oxide, and the ammonium salt of a resin obtained by heating glycerol, ethylene glycol, and the maleic anhydride adduct of a terpene fraction consisting essentially of a -terpinene.  Polyamide yarn is treated with an ammoniacal aqueous solution of a mannitol maleate resin prepared by heating mannitol and maleic anhydride in molecular ratio 10 : 8 at 150 DEG  C.  Polyamide yarn is treated with a castor oil modified phthalic anhydride-glycerol resin of acid number 100, dissolved in a solution of ammonium hydroxide.  Polyamide yarn is treated with a solution of a neutral sodium salt of a hydrolysed ethylene - maleic anhydride interpolymer, obtained by heating the reagents under pressure in presence of xylene and benzoyl peroxide and then heating the product with sodium hydroxide solution. Polyamide yarn is treated with an aqueous solution of the sodium salt of a hydrolysed propylene-maleic anhydride interpolymer.  Another example describes the treatment of polyamide yarn with an aqueous solution containing di-beta-methoxyethyl adipate and polymerised ethylene oxide as plasticisers, and an interpolymer prepared by emulsion type polymerisation from beta-methoxyethyl methacrylate and methacrylic acid using benzoyl peroxide as catalyst and methylated starch as emulsifying agent.  Other examples describe the use of aqueous solutions of the sodium salt of rosin and solutions of honey. Specifications 461,236 and 461,237 are referred to.  The Specification as open to inspection under Sect. 91 comprises also the treatment of yarns of other linear polymers, e.g. of vinyl chloride-acetate interpolymers, methyl or ethyl methacrylate polymers, chlorinated polyvinyl chloride, and polymerised ethylene. This subject-matter does not appear in the Specification as accepted.