Abstract: An open-cell cross-linked polyolefin foam possessing extremely high non-flammability is produced by dispersing a thermally expansible graphite in an adhesive agent and applying the resultant adhesive agent mixture to at least part of the surface of a flame-retardant open-cell cross-linked polyolefin foam. As the flame-retardant open-cell cross-linked polyolefin foam, an open-cell cross-linked polyolefin foam which possesses a polymer of a phosphorus type flame-retarding agent in the interior and the surface of the open-cell foam or an open-cell cross-linked polyolefin foam which contains a halogen type flame-retarding agent in the cell membranes thereof and possesses a polymer of a phosphorus type flame-retarding agent in the interior and the surface of the open-cell foam is preferably used.

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.