Japan Exlan Company Limited

Yozo Shiomi

Shigeru Sawanishi

Akira Yamane

Mituru Wakitani

Provided is a wool-like acrylic composite fiber having excellent crimp developability, dyeability and processability, which is characterized in that the difference in the amount of sulfonate groups in the higher and lower heat shrinkable fiber components constituting the fiber is defined to fall within a particular range, that the amount of sulfonate groups in the higher heat shrinkable fiber component is periodically varied within a particular range in the axial direction of the fiber, and that the product of the difference in the amount of sulfonate groups between the higher and lower heat shrinkable fiber components and the ratio of the maximum content of sulfonate groups in the higher heat shrinkable fiber component to the minimum content of the same is defined to fall within a particular range. The composite fiber has a natural hand near to that of natural wool and, when commercially dyed, it has much reduced dyeing specks. The invention can freely design various composite fibers each having a different hand in accordance with the use and the object of fibrous products to be made of such fibers.

Acrylic composite fiber

The present invention provides an industrial process for producing acrylic fibers having non-circular cross-sections which are excellent in gloss, softness, etc. In this process, which is a wet-spinning method using an inorganic solvent, a particular acrylonitrile polymer solution is spun through a spinnerette having circular spinning orifices. The steps of spinning, coagulation, water-washing and wet-heat stretching are carried out in integral combination and under specific conditions.

Process for producing acrylic fibers having non-circular cross-sections

The present invention provides a process for producing acrylic fibers having excellent surface smoothness and a color development ratio not less than 105%, without generating numerous wrinkles peculiar to wet spinning. The process comprises wet-spinning an acrylonitrile polymer spinning solution of from 50.degree. to 70.degree. C. having a viscosity of from 40 to 200 poises at 30.degree. C., (a) with a spinning draft of from 0.05 to 0.2 in the case wherein the spinnerette orifice capillary length is 0.5 mm or less, and (b) with a spinning draft of from 0.13 to 2.0 in the case where the spinnerette orifice capillary length exceeds 0.5 mm; coagulating and water-washing the resulting fibers substantially without stretching; and thereafter wet-heat-stretching the fibers not less than 4 times in length at a temperature not lower than 80.degree. C.

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Okayama, Japan

Yozo Shiomi