| 摘要 |
A fibrillar, gel-like aqueous dispersion of cellulose ethoxyl ether or of cellulose propoxyl ether, is made by subjecting an aqueous slurry of fibres of the cellulose ether to mechanical subdivision and separating the fibres into fibrils which disperse in the aqueous medium forming a creamy, gel-like product which remains stable on long standing. In a preferred method, an aqueous slurry of hydroxyethyl cellulose fibres at a consistency of 3 to 25% of hydroxyethyl cellulose and having from 3 to 12% by weight, based on the dry weight of the alkali cellulose, of substituted ethylene oxide, and a degree of polymerization of 50 to 400, is subjected to mechanical subdivision at a temperature not exceeding 95 DEG C. A swelling agent may be added to the aqueous slurry, suitably ammonia in a proportion of up to about 28%, especially about 15 to 20%. Hydroxyethyl cellulose fibres suitable for the invention may be made by steeping cellulose in 20% sodium hydroxide at 25 DEG C., and reacting the alkali cellulose with gaseous ethylene oxide in such a manner as to uniformly contact the fibres and produce hydroxyethyl cellulose of the required degree of substitution. Hydroxypropyl cellulose fibres may be made by steeping wood pulp in 18% sodium hydroxide, reacting with propylene oxide at 40 DEG C. to a substitution level of 10% propylene oxide by weight, ageing at 40 DEG C. to a degree of polymerization of 150, neutralising to pH7, washing free of salts and drying. Specification 925,900 is referred to.ALSO:Paper is coated with a fibrillar, gel-like aqueous dispersion of cellulose ethoxyl ether or of cellulose propxyl ether. The coated paper can be dried directly without need for intermediate neutralization or washing. The dried coating is water-insoluble, and has extremely good adhesive character because of the nature of the bonding between the string-like fibrils. Such dispersions are made by subjecting an aqueous slurry of fibres of the cellulose ether to mechanical subdivision and separating the fibres into fibrils which disperse in the aqueous medium forming a creamy, gel-like product which remains stable on long standing. In a preferred method, an aqueous slurry of hydroxethyl cellulose fibres at a consistency of 3-25% of hydroxyethyl cellulose and having from 3-12% by weight, based on the dry weight of the alkali cellulose, of substituted ethylene oxide, and a degree of polymerization of 50-400, is subjected to mechanical subdivision at a temperature not exceeding 95 DEG C. A swelling agent may be added to the aqueous slurry, suitably ammonia in a proportion of up to about 28%, especially about 15-20%. Hydroxyethyl cellulose fibres suitable for the invention may be made by steeping cellulose in 20% sodium hydroxide at 25 DEG C., and reacting the alkali cellulose with gaseous ethylene oxide in such a manner as to uniformly contact the fibres and produce hydroxyethyl cellulose of the required degree of substitution. Hydroxypropyl cellulose fibres may be made by steeping wood pulp in 18% sodium hydroxide, reacting with propylene oxide at 40 DEG C. to a substitution level of 10% propylene oxide by weight, ageing at 40 DEG C. to a degree of polymerization of 150, neutralizing to pH 7, washing free of salts and drying. Specification 925,900 is referred to.ALSO:Non-woven fabrics are bonded with a fibrillar, gel-like aqueous dispersion of cellulose ethoxyl ether or of cellulose propoxyl ether. The resultant dried bond is water-insoluble, and has extremely good adhesive character because of the nature of bonding between the string like fibrils. Such dispersions are made by subjecting an aqueous slurry of fibres of the cellulose ether to mechanical subdivision and separating the fibres into fibrils which disperse in aqueous medium forming a creamy, gel-like product which remains stable on long standing. In a preferred method, an aqueous slurry of hydroxy-ethyl cellulose fibres at a consistency of 3 to 25% of hydroxyethyl cellulose and having from 3 to 12% by weight, based on the dry weight of the alkali cellulose, of substituted ethylene oxide, and a degree of polymerization of 50 to 400, is subjected to mechanical subdivision at a temperature not exceeding 95 DEG C. A swelling agent may be added to the aqueous slurry, suitably ammonia in a proportion of up to about 28%, especially about 15 to 20%. Hydroxyethyl cellulose fibres suitable for the invention may be made to steeping cellulose in 20% sodium hydroxide at 25 DEG C., and reacting the alkali cellulose with gaseous ethylene oxide in such a manner as to uniformly contact the fibres and produce hydroxyethyl cellulose of the required degree of substitution. Hydroxypropyl cellulose fibres may be made by steeping wood pulp in 18% sodium hydroxide, reacting with propylene oxide at 40 DEG C. to a substitution level of 10% propylene oxide by weight, ageing at 40 DEG C. to a degree of polymerization of 150, neutralising to pH 7, washing free of salts and drying. Specification 925,900 is referred to. |
