Patent GB-571826-A (GB)
Title: Improved oriented fibres of hydroxylated vinyl interpolymers
IPC: D06M15/423
Filed: 1943-07-21
Abstract: Oriented fibres of hydrolysed interpolymers of vinyl organic esters with ethylene in which less than 45 and more than 1 per p  cent of the carbon atoms of the polymer chain are attached to hydroxyl groups or organic radicals hydrolysable to hydroxyl groups are caused to react with a cross-linking composition comprising essentially one or more substances selected from the following classes: methylol or alkoxy-methylol derivatives of ureas, melamine, and diamines, polybasic organic acids and their acid halides, or compounds having a plurality of -N=C=Y groups where Y is oxygen or sulphur.  The treatment reduces the heat and water sensitivity of the fibres.  The temperature at which they become tacky is raised.  The fibres are less liable to contract in boiling water and they are substantially insoluble in boiling water.  The molar ratio of ethylene to vinyl organic ester in the polymer prior to hydrolysis should be greater than 1 : 9. Preferably, hydrolysed interpolymers having an ethylene/vinyl alcohol ratio between 3 : 1 and 1 : 3 are used. Highly or completely hydrolysed products are preferred.  Part of the hydroxyl groups may be converted into acetal or ketal group, e.g. by mild treatment with formaldehyde or butyraldehyde.  The cross-linking agent may be trimethylolmelamine, dimethylolurea, dimethylolurone, N,N1 - di - methylolsuccinamide, N,N1 - dimethyloladipamide, or the methyl ethers of these compounds. It may be adipic acid, adipyl chloride, sebacic acid, sebacyl chloride or a polyisocyanate or poly-isothiocyanate.  The hardening agent may be dissolved in a solvent and then applied to the oriented fibres by spraying, soaking, or other method, or when the agent is sufficiently volatile it may be applied as a vapour. The fibre may be rinsed, dipped in a solution of catalyst, dried and baked.  In the case of methoxymethyl derivatives of melamine, uron, urea and diamides, a 6 per cent solution of the reagent in water may be used.  Ammonium chloride may be used as catalyst. After soaking in the solution for several hours, the fibres are air dried at raised temperature and then baked.  Water-reactive agents such as hexamethylene di - isocyanate and adipyl chloride are used in inert organic solvents, e.g. a 10 per cent solution of hexamethylene diisocyanate in toluene may be used, the fibres being soaked in the solution for an hour at 70 DEG  C.  Treatment with two or more of the various kinds of hardening agent may be effected.  The filaments may be obtained from the vinyl interpolymer by melt or solution spinning methods.  After the spinning operation the filaments, preferably after twisting, are drawn or stretched to produce molecular orientation along the longitudinal axis of the filament as revealed by X-ray diffraction patterns.  Examples describe the treatment of oriented yarn from hydrolysed ethylene-vinyl acetate interpolymers with adipyl chloride, hexamethylene di - isocyanate, N,N1,N11 - tris - (methoxymethyl) melamine, N,N1 - bis - (methoxymethyl) urea and N,N1-bis-(methoxymethyl) urone. In one example, the unoriented filaments are treated with N,N1-bis-(methoxymethyl) urea, rinsed and dried.  They are then stretched in mineral oil at 90 DEG  C. and after treatment with ammonium chloride solution are dried and baked at 135 DEG  C.  The reagent only reacts during the baking of the oriented filaments. The untreated oriented fibres may be subjected to a heat-setting treatment at constant length by heating them in air, water, aqueous salt solutions, butanol, or dilute solutions of acids. The treated filaments or fibres may be used for hosiery yarn, weaving, felts, pile fabrics, sewing thread, cordage, nets, screens, fishing lines, electrical insulation, racket strings, and bristles.