To prevent the adhesion of gel to the surface of a hollow fiber and prevent the deterioration of the feeling of cloth while avoiding the lowering of the wash durability caused by the collapse of the hollow part and the breakage of interconnection holes in the production of a functional fiber having excellent durability by filling a gel having functionality in the hollow part of a hollow fiber.
The hollow fiber has sporadically distributed interconnection holes connecting the fiber surface and the hollow part. A liquid having gel- forming property is introduced into the hollow part of the fiber through the interconnection holes, the gel-forming liquid attached to the surface of the fiber by the introduction of the liquid is removed by centrifugal force and the gel-forming liquid in the hollow part is gelatinized. The gel-forming liquid contains a functionality imparting agent.
YOSHIDA MAKOTO
MATSUI YUKIKAGE
