Economical method of making high-strength glass fiber mats particularly useful for roofing products

摘要

The glass mat made herein is comprised of two fibrous components, namely, individual filament glass fibers and extended glass fiber elements. These components are formed herein in situ in a wet-laid process from original bundles of glass fibers. The individual filaments appear by conventional filamentation of the bundles. The extended fiber elements, however, are formed by longitudinal extension of a given bundle whose fibers are connected longitudinally. Thereby the effective length of a fiber element is very much greater than the length of the fibers therein. The fiber elements are further characterized by a non-uniform diameter, as contrasted to the fibers themselves, being thicker in the midsection of the element where connection of fibers is maximized, and tapered towards its ends, where fiber connection is at a minimum.P PThe extended fiber elements preferably predominate by weight of the fibrous content of the mat over the individual filaments. The desired ratio of the two components is achieved in the method of the invention by using bundles whose fibers have a long length, and by very gentle agitation of the dispersion slurry for a short period of time.