Superabsorbent cellulosic fibers having a coating of a water insoluble, water absorbent polymer and method of making the same

A cellulosic fiber having a rapid rate of absorption and a high absorption capacity for water or aqueous salt solutions which comprises a long fiber cellulose in the form of separate and discrete fibers having on their surfaces a coating of water-insoluble, water-absorbent polymer in an amount equal to 15 to 90% by weight based on the total weight of the coated fiber, said water-absorbent polymer being selected from the class consisting of cross-linked sodium carboxymethyl cellulose, cross-linked partial free acid carboxymethyl cellulose, cross-linked hydroxyethyl cellulose, cross-linked cellulose-acrylamide-acrylic acid copolymers and cross-linked acrylamide-acrylic acid copolymer, said coated fiber having a higher absorption capacity than the uncoated long fiber cellulose.

A cellulosic fiber having a rapid rate of absorption and a high absorption capacity for water or aqueous salt solutions which comprises a separate and discrete staple cotton fiber having on its surfaces a coating comprising about 40 to 90% by weight of partial free acid carboxymethyl cellulose based on the total weight of the coated fibers, said coated fiber having a higher absorption capacity than the uncoated staple cotton.

A cellulosic fiber having a rapid rate of absorption and a high absorption capacity for water or aqueous salt solutions which comprises a separate and discrete wood pulp fiber having on its surfaces a coating comprising about 40 to 90% by weight of partial free acid carboxymethyl cellulose based on the total weight of the coated fiber, said coated fiber having a higher absorption capacity than the uncoated wood pulp.

A cellulosic fiber having a rapid rate of absorption and a high absorption capacity for water or aqueous salt solutions which comprises a separate and discrete chemical cotton fiber having on its surfaces a coating comprising about 40 to 90% by weight of partial free acid carboxymethyl cellulose based on the total weight of the coated fiber, said coated fiber having a higher absorption capacity than the uncoated chemical cotton.

A blend of an untreated long fiber cellulose and a long fiber cellulose having a higher absorption capacity than said untreated long fiber cellulose comprised of separate and discrete fibers coated with a water-insoluble, water-absorbent polymer and having a ratio of coated to uncoated fibers such that the total concentration of water-insoluble, water-absorbent polymer in the blend is about 15 to 80%.

A method of preparing cellulosic fibers having a rapid rate of absorption and a high capacity for water or aqueous salt solutions which comprises preparing an aqueous suspension of separate and discrete long fiber cellulose fibers containing a water-insoluble, water-absorbent polymer, stirring the suspension until the water-insoluble, water-absorbent polymer forms an aqueous gel, adding to the suspension an inert water-miscible diluent in which the polymer is neither soluble nor swellable to precipitate the polymer onto the surface of the long fiber cellulose and thereafter dehydrating the coated fibers by contacting them with a water-miscible diluent in which the polymer is neither soluble nor swellable, removing the diluent and recovering separate and discrete long fiber cellulose fibers therefrom.