Acoustical gypsum board for ceiling panel

Abstract

Low density acoustical gypsum boards having a perforated cover sheet that have good sound absorption properties and are generally clear of falling gypsum dust. The invention optionally provides a cover sheet having a pattern producing a textured visual effect particularly when viewed from a distance. The acoustical gypsum boards can be produced on modified existing gypsum board lines.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a lightweight gypsum board suitable for use as a soundproofing or acoustical panel. The invention provides economical and convenient-to-use low density acoustical gypsum boards having sound absorbing characteristics on a par with conventional acoustic panels and a method for their preparation. BACKGROUND OF THE INVENTION [0002] Acoustical panels are used to form soundproofing interior surfaces. They typically come in the form of ceiling panels, wall panels, and partitions (e.g., partitions between office cubicles), and are used in commercial buildings, residential buildings, public buildings, auditoriums, etc. The panels are generally planar and include acoustical characteristics derived from the materials selected for their manufacture and from their ability to accept sound absorbing perforation without adversely affecting their durability. [0003] Most common acoustical panels are mineral wool-based, and may also includ...

AI Technical Summary

Problems solved by technology

Both water felting and tray casting techniques for preparing acoustical panels are not entirely satisfactory because of their complexity and expense.

In addition to raw material costs, these processes require large amounts of water and energy.

Furthermore, panels prepared according to these methods may be subject to sagging, especially if the panels are stored under conditions of high humidity or when the panels are installed horizontally on widely spaced supporting members.

However, such paper covered gypsum wallboard has not in the past been considered for use in acoustical ceiling panels for a number of reasons.

First, such gypsum wallboard does not inherently have good sound absorption properties.

Even if it is punched or perforated in the same manner as conventional mineral wool-based acoustical panel, little or no significant sound absorption improvement is achieved.

Furthermore, punching conventional paper covered gypsum wallboard causes substantial amounts of gypsum dust to loosen and fall from the perforated holes.

(Conventional acoustical panels also can exhibit some dust (powder) loss.)

Also, conventional gypsum wallboard may be heavy, ca.

40 lbs / ft3 (“pcf”), and this weight makes conventional wallboard unsuitable in most acoustical applications.

Therefore, the problems of lack of sound absorption, high density, and gypsum dust loss have discouraged the use of either conventional or lightweight face-sheeted gypsum board in acoustic tile applications.

In a less preferred embodiment of Englert et al. a top face paper is used but there is no suggestion to perforate after drying, which is not surprising because perforating this dried board would be expected to produce substantial dust loss.

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