Patent GB-905044-A (GB)
Title: Chemical modification of cellulose and cellulose derivatives
Inventor: LANDELLS GEORGE
IPC: D21H17/49
Filed: 1959-10-08
Abstract: 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 superheated steam, a swelling agent e.g. caustic soda, or a resin, e.g. polyvinyl alcohol.  A particularly suitable composition for use in the treatment comprises 5-25 parts by weight of dimethylol dihydroxyethylene urea and 95-75 parts by weight of aqueous sulphuric acid of normality between 4N and 12,5N.ALSO: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 methylolated nitrogen containing compound or compounds or ether thereof or nitrogen containing compound containing 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 neutralising and rinsing in water, and the material dried in order to improve its wet crease recovery, dimensional stability and ability to receive dyeing and finishing operations. 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 while 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 1-1ON sulphuric acid for 2-3 hours.  2ON sulphuric acid may be used to obtain a parchmentising effect.  Acid dispersible cellulose ethers may be included in the acid liquor.  Fabrics may be pleated while in the wet state after impregnation, the treatment serving to set the pleats.  Prior to treatment the material may be glazed or pretreated with steam or superheated steam, a swelling agent, e.g. caustic soda, or a resin, e.g. polyvinyl alcohol.  The material may subsequently be treated with stiffening agents, softening agents, water repellents, e.g. waxes, silicones or fatty chain pyridinium compounds, fluorescent brighteners, resins, e.g. amino-formaldehyde condensates, or swelling agents, e.g. caustic soda, and dyed with direct cotton dyes, vat dyes, solubilised vat dyes, azoic dye combinations or reactive dyes.