Fiber size, sized reinforcements, and articles reinforced with such reinforcements

Abstract

The present invention relates to fiber-size compositions for coating glass or other reinforcing fiber materials that are used in the manufacturing of composites. The fiber-size composition contains at least about 4% by weight of a polyvinylpyrrolidone film former, at least one lubricant and a coupling agent. The sizing composition gives the fibers desirable properties such as high strength, improved flexibility, fuzz formation resistance, and fiber smoothness and softness.

Description

TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION [0001] The present invention relates to fiber-size compositions for coating glass or other reinforcing fiber materials that are used in the manufacturing of composites. The sizing composition gives the fibers desirable properties such as high strength, improved flexibility, fuzz formation resistance, and fiber smoothness and softness. BACKGROUND OF THE INVENTION [0002] Glass fibers are useful in a variety of technologies. For example, glass fibers are commonly used as reinforcements in polymer matrices to form glass fiber reinforced plastics or composites. Glass fibers have been used in the form of continuous or chopped filaments, strands, rovings, woven fabrics, nonwoven fabrics, meshes, and scrims to reinforce polymers. It is known in the art that glass fiber reinforced polymer composites possess higher mechanical properties compared to unreinforced polymer composites, provided that the reinforcement fiber surface is su...

AI Technical Summary

Benefits of technology

[0008] Optional additives may be added to the fiber-size composition, such additives include, but are not limited to wetting agents, lubricants, surfactants, and antifoam agents. An additional polyurethane film-former can also be used in the fiber-size composition to improve the processing characteristics of the size composition and is also useful in maintaining fiber integrity during the processing of coated fibers. Polyurethane provides good adhesion to a variety of matrix resin polymers, is UV stable, hyrodlytically stable and easily dispersible in aqueous systems.

[0009] Glass fibers are typically coated with the fiber-size composition as part of the fiber filament formation process. By coating the fiber with the size composition early in its formation stage, the fiber size coating protects the filaments from abrasion and breakage as the filaments are formed into fibers and wound or chopped for further processing.

[0016] It is an object of the present invention is a sizing composition useful to prevent fuzzing comprising substantial amount of a polyvinylpyrrolidone (PVP) film former.

[0023] As used here, the term “size” or “sizing” refers to a coating that is applied initially to forming filaments of a fiber for the purpose of protecting the fiber from abrasion breakage of the fibers during further processing of the fibers and subsequently promoting the adhesion between the fibers and the materials which they reinforce. While some physical binding between filaments may occur when the filaments are bundled into threads, it is essential that the sizing not interfere with the dispersion of the fibers in the matrix into which h the fibers are incorporated. That is, the sizing should not have a tendency to agglomerate the threads, especially when incorporated into a matrix composition. This is in contrast to a “binder” where the formulation promotes the binding of threads to each other at their intersection (crossing points) in such forms as mats, fabrics and nonwovens through the polymerization of the binder while it is in contact with the fibers. One of the purposes of a size is to coat the entire filament in order to protect the filaments and fibers during initial formation of the filaments and fibers and in their subsequent processing.

Problems solved by technology

This is a result of the film-former forming a brittle film which leads to fiber breakage as it crosses contact points in the manufacturing operation.