Novel water-swellable fibers having a high degree of water-swellability and excellent physical properties and process for producing the same
AssigneeJapan Exlan Company Limited
InventorKoji Tanaka
Life of this patent
Estimating the term…
Abstract
Novel water-swellable fibers having a multiple layer structure consisting of an hydrogel outer layer and an inner layer of an acrylonitrile polymer and/or another polymer, which combine a high degree of water-swellability with excellent physical properties, and a process for producing the same.
Claims10
Water-swellable fibers with a high degree of swellability composed of an outer layer of a hydrophilic crosslinked polymer and an inner layer of an acrylonitrile polymer, such fiber being produced by contacting acrylonitrile fibers with an aqueous solution of an alkali-metal hydroxide of a high concentration not less than 6.0 mol/1000 g, or an aqueous solution of an alkali-metal hydroxide of a low concentration coexisting with an electrolytic salt of a concentration not less than 0.5 mol/1000 g for a sufficient time to cross-link and render the outer layer of the fibers hydrophilic, thereby producing fibers having said hydrophilic cross-linked outer layer and a non-cross-linked, non-hydrophilic acrylonitrile inner layer.
Water-swellable fibers with a high degree of swellability of from 3 to 300 cc/g which consists essentially of an outer layer of a hydrophilic carbon-carbon covalent bonded cross-linked acrylonitrile polymer containing 0.1 to 4.0 m mol/g fiber of salt-type carboxyl groups represented by --COOX, wherein X is an alkali-metal or NH.sub.4, and an inner layer of an acrylonitrile polymer.
Dependencies are inferred from the claim text.