Microfiber-containing fiber reinforced facer mats and method of making

Abstract

Fiber-reinforced composite mats are described that include a non-woven web of fibers. The web of fibers may include a first group of fibers having an average fiber diameter from about 8 μm to about 25 μm, and a second group of fibers having an average fiber diameter from about 0.5 μm to about 6.5 μm. A binder bonds together the non-woven web of fibers into the fiber reinforced composite having an air permeability of 250 cfm / ft2 or less. Also described are gypsum boards that include one or more facers affixed to at least one surface of the gypsum board. The facers may be made from the above, described fiber-reinforced composite mats.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]The present application is related to co-assigned U.S. Pat. Nos. 7,829,488 issued Nov. 9, 2010, and 7,258,759 issued Aug. 1, 2007. It is also related to co-assigned U.S. patent application Ser. No. 12 / 383,027 filed Mar. 19, 2009. The entire contents of these patent and patent application are herein incorporated by reference for all purposes.FIELD OF THE INVENTION[0002]Embodiments of the invention relate to construction materials used in building construction, including fiber-reinforced composite faced construction board, such as gypsum board. The fiber-reinforced composite facers on exposed surfaces of the construction board may include a glass fiber mat made from a blend of large and small diameter glass fibers bonded together with a binder, such as an organic or inorganic binder.BACKGROUND OF THE INVENTION[0003]Wallboard formed of a gypsum core sandwiched between facing layers is used in the construction of virtually every modern buildi...

AI Technical Summary

Benefits of technology

The patent describes fiber-reinforced composite mats for use in construction materials such as boards. The mats have smooth surfaces, stronger internal bonds to prevent delamination, require less paint, and have better resistance to fire and mold. The low air permeability of the mats prevents bleedthrough from construction materials, resulting in a smoother surface. Overall, the mats improve the quality and efficiency of construction.

Problems solved by technology

While paper is widely used as a facing material for gypsum board products because of its low cost, many applications demand water resistance that paper facing cannot provide.

Upon exposure to water either directly in liquid form or indirectly through exposure to high humidity, paper is highly prone to degradation, such as by delamination, that substantially compromises its mechanical strength.

Consequently, paper-faced products are generally not suited for exterior or other building uses in which exposure to moisture conditions is presumed.

In addition, there is growing attention being given to the issue of mold and mildew growth in building interiors and the potential adverse health impact such activity might have on building occupants.

A further drawback of paper-faced gypsum board is flame resistance.

In a building fire, the exposed paper facing quickly burns away.

Although the gypsum itself is not flammable, once the facing is gone the board's mechanical strength is greatly impaired.

At some stage thereafter the board is highly likely to collapse, permitting fire to spread to the underlying framing members and adjacent areas of a building, with obvious and serious consequences.

However, gypsum board products incorporating the fibrous mats have proven to have certain drawbacks: Some persons are found to be quite sensitive to the fiberglass mat, and develop skin irritations and abrasions when exposed to the mat at various stages, including the initial production of the mat, the manufacture of composite gypsum board with the mat facing, and during the cutting, handling, and fastening operations (e.g., with nails or screws) that attend installation of the end product during building construction.

As a result, workers are generally forced to wear long-sleeved shirts and long pants and to use protective equipment such as dust masks.

Such measures are especially unpleasant in the sweaty, hot and humid conditions often encountered either in manufacturing facilities or on a construction jobsite.

In addition, many commercial fiber-faced construction boards have a surface roughness that makes them difficult to finish satisfactorily by normal painting, because the texture of the mat remains perceptible through the paint.

Moreover, making the construction board may involve the deposition of a relatively wet slurry onto the fiber-reinforced mat, which is generally found to result in considerable intrusion of the slurry through the mat and onto the faced surface.

Prevention of this excess intrusion typically requires very careful control of the slurry viscosity, which, in turn, frequently leads to other production problems.

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