PURPOSE: To produce a base cloth for non-coat air bag composed of an ultrafine high-strength multifilament and having excellent mechanical strength, flexibility and foldability and low gas permeability.
CONSTITUTION: A high-strength sea-island conjugate fiber having a single fiber fineness of ≥3de, a crystallite volume of ≥8×1043, a meridian long-period of ≥120, a crystal orientation of ≥0.9, an amorphous part orientation of ≥0.975 and a tensile strength of 2 T g/de is produced by using a PET having an intrinsic viscosity of ≥1.0 as the island component and a PET copolymerized with a sulfoisophthalic acid salt as the sea component, extruding both components in molten state, spinning the molten extrudate by slowly cooling in a hot atmosphere of 200-350°C under the spinneret and drawing the spun fiber at a draw ratio of ≥3 before winding. A multifilament of the fiber having a total fineness of 100-1,000de (preferably 180-450de) is woven at a cover factor K of ≥1,900 and the sea-component is removed to obtain a base cloth for non-coat air bag, composed of ultrafine multifilament having a single fiber fineness of <0.8de, a tensile strength of ≥6.5g/de and an elongation of ≥15%, exhibiting excellent tensile strength and flexibility of the cloth and having a gas transmission rate of ≤5.0cc/sec/cm under a pressure head of 1.27cm water.
TAWARA AKIO
TAKAHASHI HIROSHI
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