Melt-spun drawn or undrawn flame-resistant and antifusing cured epoxy-modified novolak filaments and process for production thereof

A process for producing a flame-resistant and antifusing cured, epoxidized, phenol-aldehyde continuous filament comprising:

• A. melting an uncured resin consisting of an epoxidized phenol-aldehyde novolak resin having no substituents other than a 5 to 60% substitution degree of glycidyl etherification of the phenolic hydroxyl group;
• then
• B. forming a filament from the uncured molten resin by melt-spinning;
• and then
• C. curing the melt-spun filament by
• (1) contacting the melt-spun filament with a curing agent selected from at least one of the group consisting of
• (a) a curing agent for phenolic resins in combination with an acid or base catalyst, the curing agent being an aldehyde selected from at least one of the group consisting of:
• formaldehyde, paraformaldehyde, trioxane, tetraoxane, polyoxymethylene, benzaldehyde, hexamethylene tetramine, and furfuraldehyde;
• and the catalyst being selected from one of the group consisting of:
• acid catalysts consisting of hydrochloric, sulfuric, nitric, acetic, oxalic, formic, orthophosphoric, butyric, lactic, benzenesulfonic, p-toluenesulfonic, and boric acids, and mixtures thereof;
• and basic catalysts consisting of ammonia, ammonium hydroxide, alkali metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates, alkaline earth metal carbonates, and mixtures thereof;
• (b) a curing agent for epoxy resins, which is selected from the group consisting of ethanolamine, triethylenetetramine, diaminodiphenylmethane, m-phenylenediamine, trifluoroboronmono-ethylamine, diaminodiphenylsulfone, phthalic anhydride, hexahydrophthalic anhydride, heptoic acid, phenol, and tris-(dimethylaminoethyl)phenol, and
• (2) heating the melt-spun filament to a temperature of at least 60.degree. C., with the proviso that the upper temperature of heating step (2) is about 140.degree. C. if the curing agent (a) is used and is about 120.degree. C. if curing agent (b) or a combination of curing agents (a) and (b) is used.