| 摘要 |
PURPOSE:To provide the title novel fiber simultaneously provided with a strength required for a reinforcing fiber and a water-absorbing property, by comprising a hydrophilic crosslinked polymer in part of the outer layer portion of the fiber and an acrylonitrile polymer, etc., in the residue thereof and containing salt type carboxyl groups. CONSTITUTION:The objective fiber comprises a hydrophilic crosslinked polymer in at least part of the outer layer portion of the fiber and an acrylonitrile polymer (hereinafter referred to as AN) and/or other polymers in the residue thereof, is combined with salt type carboxyl groups of the formula -COOX (X is alkali metal or NH4) in an amount of >=0.1mmol./g and has a strength of >=5g/d. The fiber is preferably produced by a method wherein an AN series high strength fiber is subjected to a hydrolysis treatment using an alkali metal hydroxide aqueous solution having a high concentration of >=9mol./1,000g solution at 100-130 deg.C for 10-30min, etc. The aforementioned AN series high strength fiber is preferably that having a weight retaining rate of >=90% when subjected to a boiling water treatment in a 2N caustic soda aqueous solution for 10min. |
