Gaf Corporation

B Randall Ziegler

Alfredo A Bondoc

V Robert Canfield

An improvement in the apparatus for the production of air laid fiberglass mat is provided. Fiberglass strands from bobbins, rovings or other sources are fed into a chopper assembly for chopping into smaller in length strands. The smaller in length strands then drop by gravity from the chopper assembly and are picked up by an air stream created by a fan or blower located below the chopper assembly. This air stream directs these smaller in length strands into the inlet of the fan or blower. In an alternative, already chopped strands could be fed directly into the inlet of the fan or blower eliminating the need for the chopper assembly. Fan or blower blades then work on these smaller in length fiberglass strands as they pass from the inlet to the exit of the fan or blower to open or fluff said smaller in length fiberglass strands into partially opened strands. The partially opened strands are then directed by the air stream caused by the air stream caused by the fan or blower through an expanding duct. After the partially opened exit the expanding duct the air stream causes the partially opened strands to be deposited onto a moving foraminous conveyor to form an air laid glass mat of uniform thickness. Since the air stream created by the fan or blower is allowed to continue through the foraminous conveyor and there is a vacuum applied from behind the foraminous conveyor, and opposite the outlet of the expanding duct, a uniform deposit of partially opened fiberglass strands onto the conveyor is assured.

Apparatus for air laid fiberglass mat

What is provided herein is a glass fiber mat having a novel structure and high-strength properties which is particularly useful for roofing products, including built up roofing membranes and systems. The glass mat of the invention is comprised of two fibrous components, namely, individual filament glass fibers and extended glass fiber elements, which are formed 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 mid-section of the element where connection of fibers is maximized, and tapered towards its ends, where fiber connection is at a minimum. The 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 by using bundles whose fibers have a long length, and by very gentle agitation of the dispersion slurry for a short period of time.

High-strength glass fiber mat particularly useful for roofing products

High-strength built-up roofing (BUR) membranes and systems are provided herein. These BUR products are made using improved glass fiber mat structures having unusual tear resistance in place of organic felts. The glass fiber mats are constructed from two fibrous components, namely, individual filaments, which provide the uniform denseness required for impregnation of saturant asphalt in the interstices of the mat, and extended fiber elements formed by longitudinal extension and connection of fibers from bundles of glass fibers in a wet-laid process, which furnish tear resistance and tensile strength to the BUR membranes and systems. The BUR membranes and systems of this invention have exceedingly high strengths compared with commercially available products of similar construction, and, advantageously, they can be manufactured by a very economical process.

High-strength built-up roofing using improved glass fiber mats

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. The 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.

Economical method of making high-strength glass fiber mats particularly

A cotton reinforced, cementitious, hydrated product is made by combining on a dry basis between about 25 and about 75 wt. % Portland cement, between about 1 and about 15 wt. % cotton fiber, between about 3 and about 30 wt. % inorganic filler and preferably between about 10 and about 40 wt. % silica with water to form an aqueous slurry. The slurry is formed into desired shapes such as sheets or slabs and cured by autoclaving to produce the desired product.

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Freehold, NJ, United States of America

B Randall Ziegler