Melamine resin flame-retardant fibers

A bi-component, flame retardant, lightfast, thermally infusible, essentially smokeless, substantially uniform denier fiber exhibiting a substantially homogeneous cross-section along its longitudinal axis, said fiber having a degree of water swelling of less than about 2.0, a denier of between about 0.5 to 1000, birefringence of less than about 0.02, a tenacity of between about 1.6 and 5.0 grams/denier, whiteness of greater than about 0.7, heat shrinkage of less than 10% at 300.degree. C., said fiber including at least 60% by weight of a first component which comprises a cured, amine/aldehyde thermosetting pre-condensate, said amine/aldehyde thermosetting pre-condensate being water soluble and having a degree of hydroxyalkylation of between about 1.5 and 6, said thermosetting pre-condensate being comprised of at least 60% by weight amine/aldehyde condensable comonomers and up to 40% of a third comonomer co-condensable therewith, and the amine comonomer comprising said pre-condensate being selected from the group consisting of melamine, N-substituted melamine, guanamine, substituted guanamine, and mixtures thereof;

• and from 0.02 to 40% by weight of a second component which comprises a thermoplastic, fiber-forming, water-soluble polyvinyl alcohol resin compatible with the component amine/aldehyde thermosetting pre-condensate, said polyvinyl alcohol resin having a degree of polymerization of from 500 to 3200 and a degree of saponification of from 75 to 100 mole %.