Abstract: A heat resistant and/or fire retardant synthetic fiber is obtained by a process comprising immersing a polyethylene fiber into a solution of acrylic acid or impregnating a polyethylene fiber with a solution of acrylic acid and irradiating the polyethylene fiber with an ionizing radiation to graft polymerize the polyethylene fiber with at least 15%, based on the weight of the polyethylene fiber, of acrylic acid, or a process comprising irradiating a polyethylene fiber with an ionizing radiation and then immersing the polyethylene fiber into a solution of acrylic acid or impregnating the polyethylene fiber with a solution of acrylic acid to graft polymerize the polyethylene fiber with at least 15%, based on the weight of the polyethylene fiber, of acrylic acid.

Abstract: A method for manufacturing heat-resistant polyvinyl chloride fiber is given without injuring the flame-retardance of the polyvinyl chloride fiber, by grafting acrylic acid or calcium acrylate onto polyvinyl chloride by a radiation chemical process. The polyvinyl chloride fiber is irradiated either in contact with a mixture of water, ethylene dichloride and acrylic or in contact with a mixture of methanol, water, ethylene dichloride and calcium acrylate. In the case of the grafting of acrylic acid the graft fiber is subjected to a heat treatment or grafted polyacrylic acid is converted to a divalent metal salt.

Abstract: Novel antiflaming fibers having excellent dyeability and heat resistance are prepared from a matrix-polymerized resin which comprises polymerizing acrylonitrile in the matrix of a vinyl chloride resin. A vinyl chloride resin and/or an acrylonitrile resin can be added in a specific amount to the matrix-polymerized resin when dissolved in a spinning solvent. Substantially the same fibers are also prepared from blended polymers which comprise blending a specific vinyl chloride resin and a specific acrylonitrile resin in the specific proportion, by employing the coagulation bath of an aqueous solution of calcium chloride.