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US 4,689,045 AGranted
Procedure for the preparation of modified cellulose
AssigneeLa Cellulose Du Pin
InventorsSylviane Armagnacq, Michel Bol
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AssigneeLa Cellulose Du Pin
InventorsSylviane Armagnacq, Michel Bol
Estimating the term…
A dry fibrous product made from modified cellulose, having improved properties of absorption and water and physiological liquid retention, as well as its production procedure. The cellulose contained in a cellulose paste is activated, acrylonitrile is grafted to the cellulose while its dry content is sufficient to obtain a grafting rate of about 200%; the grafted cellulose paste is hydrolyzed with an alkali; the product is washed with water until a state of maximum expansion is reached; the product is acidified to a pH which brings it to a state of minimum expansion after the water is removed; the product is converted to its salt form in the presence of a water-miscible liquid, and under an agitation which is sufficient to prevent the clustering of the fibers; this is effected so that the quantity of water, expressed by volume, does not exceed about 10% of the liquid phase; the product is dried.
Dry modified cellulose-based fibrous product, comprising cellulose fibers to which a polymer in the form of an alkaline metal salt issuing from a polymerizable monomer at olefinic non-saturation, having hydrolyzable functional groups, is chemically grafted, characterized in that it has a water absorption capacity under a pressure of 25 mbars, which is greater than about 35 g per g of product, a 1% NaCl saline solution absorption capacity, under a pressure of 25 mbars, which is greater than about 15 g per g of product, a saline solution absorption speed which is greater than 15 g per minute and per g of product, and has a defiberability index, determined by the defibration time necessary to obtain a sheet without defibration defects from a past sample placed in a bowl equipped as an electric coffee grinder, which is under 20 seconds.
Dependencies are inferred from the claim text.