Chemical modification of cellulose and cellulose derivatives

Material consisting wholly or in part of cellulose or of a cellulose derivative which contains free hydroxyl groups, e.g. cellulose diacetate, is treated with an aqueous liquor which contains a methylated nitrogen containing compound or compounds or ether thereof or nitrogen containing compound containing C substituted methylol groups and an acid so that the material is swollen and maintained in the swollen condition while reaction therewith takes place and the acid then removed, e.g. by neutralizing and rinsing in water, and the material dried. The cellulosic material may be in the form of pulp, fibres, yarns, woven or knitted fabrics or sheet material, e.g. non woven fabrics, paper and regenerated cellulose films, alone or mixed with other fibres, e.g. wool, regenerated protein, nylon, polyethyleneterephthalate, cellulose triacetate or acrylic fibres. Suitable methylolated nitrogen compounds and ethers thereof are polymethylol derivatives of urea, dicyandiamide, adipamide, ethylene urea, dihydroxy ethylene urea, alkyl and alkoxy derivatives of ethylene urea, acetylene diurea, propyleneurea, melamine, ammeline, formoguanamine, triazones, e.g. methyl, ethyl and hydroxyethyl-triazones, hydantoin and substituted hydantoins, uron and substituted urons, and the compounds obtained by the reaction of pyruvic aldehyde or a -hydroxyadipaldehyde with urea and formaldehyde. When using methylol derivatives of urea the pH of the aqueous liquor should be 5-6 and long treatment times and high temperatures utilized or strong acids may be used if aldehydes, e.g. formaldehyde, glyoxal, pyruvicaldehyde or a -hydroxyadipaldehyde, or alcohols, e.g. methanol, glycol or glycerol, are added. Suitable acids are mineral acids, e.g. sulphuric, nitric, hydrochloric and phosphoric acids, strong organic acids, e.g. trichloracetic acid, and weak organic acids, e.g. formic, acetic, tartaric, citric and oxalic acids. The material may be treated by steeping it in a bath of acidic liquor for the appropriate reaction time, by circulating the acidic liquor by mechanical means through a mass of pulp or fibres or by padding, batching the material and allowing it to stand for the required period of time when wrapped in impervious material, e.g. polyethylene sheeting, to prevent drying out. The material is preferably treated at room temperature with a reaction liquor containing 1-10N sulphuric acid for 2-3 hours. Prior to treatment the material may be glazed or pretreated with steam or superheat