| abstract |
In one general aspect, the invention involves applying a chemical treatment to fibers, such as reinforcing fibers suitable for making a composite article, so as to size and/or preimpregnate the fibers. The chemical treatment has a relatively low viscosity and is substantially solvent-free and non-radiation curable. Heat energy may be employed to lower the viscosity and improve the wetting ability of the applied treatment and/or to increase the molecular weight of, or otherwise cure, the treatment with essentially no generation of solvent vapor. The treated fibers are used to form a composite strand, which may be subsequently processed in-line or off-line into a composite article having fibers disposed in a polymeric matrix. Another general aspect relates to encased composite strands, in thread or pellet form, and to wire-coating methods and apparatus for making them. The strands are moldable into fiber-reinforced thermoplastic composite articles. Each strand is made from fibers, including reinforcing fibers and optionally fibers of a matrix material, that are impregnated with a chemical treatment so that the treatment is disposed between substantially all of the fibers. |