Process for sizing metal oxide coated non-metallic or semimetallic filaments

#This invention relates generally to the surface treatment of metallic filaments, and particularly metal-plated semimetallic and polymeric fibers. More particularly, the invention relates to sizing and/or oxidizing metallic filaments, e.g., metal-plated carbon fibers to afford properties which enhance the fibers as blending materials with plastics and as weaving materials.

#It has been known for some time that metallic filaments, e.g., filaments of metals, and metal coated nonmetals and semimetals such as carbon, boron, silicon carbide, polyesters, polyamides, and the like in the form of filaments, fibers, mats, cloths and chopped strands are extremely desirable and beneficial, for example, in reinforcing organic polymeric materials.

#Typically, the metallic filaments are blended with polymeric materials to form articles where low weight-high strength applications are desirable. Aircraft, automobile, office equipment and sporting goods are among the many applications for reinforcement by high strength fibers.

#The invention will be more readily understood by reference to the drawing, which is a cross-sectional elevational schematic view of the process and apparatus to size and/or surface-oxidize metallic filaments, e.g., metal-coated high strength fibers.

#The process and apparatus of the present invention are directed to providing the surface of metallic filaments and similar articles with properties desirable for weaving and blending the product. The process and apparatus, in essence, provide metallized filaments, e.g., fibers, with a sizing material or materials that impart various properties to them, such as lubricity and bulk, and enhanched compatibility with plastics, and improved resistance to moisture, e.g., when mixed with polymers.

#For convenience, the following discussion will deal with metal-coated fibers, although it is to be understood that metallic filaments can be processed also.

#As best seen, in the drawing, the apparatus consists of pay-out reels 2, sizing sections 4, heating assemblies 6, and a capstan 8. As will be explained later, section 4 can comprise a single tank and one or more heating assemblies 6 can be used. Furthermore, means 32 for providing an oxidized surface, such as low pressure steam boxes, can also be included.