Patent GB-813516-A (GB)
Title: Treatment of cellulose ester materials
IPC: D06M13/368
Filed: 1956-06-28
Abstract: Materials having a basis of a cellulose ester of a lower fatty acid, i.e. a fatty acid containing up to four carbon atoms, and having at the most 0.29 alcoholic hydroxyl groups per anhydroglucose unit, are treated with a hot liquid polyhydric alcohol.  Suitable polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, 1 : 2 - propylene glycol, 1 : 3-propylene glycol, glycerol, triethanolamine, diethanolamine, 1 : 4-butylene glycol, 1 : 3-butylene glycol or other butylene glycol or mixtures of two or more of these alcohols.  The material may be physically held to constant dimensions or stretched during treatment but is preferably in a relaxed, free-to-shrink state. The material may subsequently be dyed and (or) treated with suitable finishing agents, examples of which are given (see Group IV (c)).  Particular reference is made to the treatment of cellulose triacetate materials but other lower fatty acid esters of cellulose of low hydroxyl content, e.g. the propionate, butyrate, mixed acetate - propionate, mixed acetate - butyrate and mixed acetate-formate esters may be treated alone or with other fibrous materials, e.g. wool, cotton, rayon, glass and asbestos. The treatment increases the crystal size and crystalline orderliness of the cellulose ester and raises its safe ironing temperature as well as its resistance to glazing and to shrinkage on pressing with moist steam, and improves its dimensional stability during laundering.  Specifications 758,442, 775,406 and 791,392, [both in Group IV (c)], are referred to.ALSO:Materials having a basis of a cellulose ester of a lower fatty acid, i.e. a fatty acid containing up to four carbon atoms, and having at the most 0.29 alcoholic hydroxyl groups per anhydro-glucose unit, are treated with a hot liquid polyhydric alcohol.  Suitable polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, 1 : 2-propylene glycol, 1 : 3-propylene glycol, glycerol, triethanolamine, diethanolamine, 1 : 4-butylene glycol, 1 : 3-butylene glycol or mixtures of two or more of these alcohols.  The treating bath may contain a dispersed cellulose acetate dye or a vat dye, of which numerous examples are given.  The material may be subjected to a heat treatment of the kind described in Specification 758,442 and then treated in the hot polyhydric alcohol containing a dyestuff.  Alternatively, the material may be treated with the heated polyhydric alcohol and then dyed or printed as described in Specification 775,406 or 791,392, preferably while still wet with the polyhydric alcohol or from an intermediate wash with water.  The wash-fastness of the dyed material may be further improved by treating with a strong stripping agent, e.g. sodium hydrosulphite, which removes all of the dye available at the surface of the material, and by a heat treatment which involves subjecting the dyed material to infra-red radiation, hot air or direct contact with hot rolls.  The material may subsequently be finished with suitable finishing agents, e.g. polysiloxanes containing methyl or other hydrocarbon groups, and preferably also hydrogen atoms directly attached to silicon atoms, waxy polyethylene, waxy sulphonated fatty materials, waxy cationic long chain amine compounds, finely divided silica, finely divided titanium dioxide, and resinous or resin-forming condensation products such as the reaction products of formaldehyde with urea, thiourea, ethylene urea or melamine and alkylation products of such reaction products, e.g. di-(methoxymethyl)-urea, tri-(methoxy-methyl)-melamine or N : N1-di - (methoxymethyl) - ethylene urea.  Particular reference is made to the treatment of cellulose triacetate materials, but other lower fatty acid esters of cellulose of low hydroxyl content, e.g. the propionate, butyrate, mixed acetate-propionate, mixed acetate-butyrate and mixed acetate-formate esters, may be treated alone or with other fibrous materials, e.g. wool, cotton, rayon, glass and asbestos.