Acoustical Panel Structure

The present invention relates to an improved honeycomb cored acoustical panel.

In pending U.S. patent application Ser. No. 98,794 filed Sept. 21, 1987, there is disclosed an acoustical panel structure which comprises a honeycomb core having a thin, dense, sound transmitting substantially homogenous, preformed sheet or mat adhered on each of the major surfaces thereof. One of the mats advantageously is provided with a decorative coating or layer. The structure of said application has a flame spread of less than 25 which qualifies it for a Class A fire rating, and it has a noise reduction coefficient of about 50.

In accordance with the present invention, an improved acoustical panel structure has been evolved which has important advantages over the structure disclosed in said pending U.S. patent application. More specifically in this connection, the structure of this invention, while retaining all of the features particularly the Class A fire rating and the capability for easy installation on a surface, of the structure of said pending patent application, has a significantly greater noise reduction coefficient, and affords wider and more diverse installation possibilities than the structure of said application. Thus, the structure of this invention has a noise reduction coefficient of upwards of 75, or at least 30% greater than that of the structure of said application. The structure of this invention, moreover, lends itself to fabrication in substantially any size making it suitable for ceiling installations as well as wall installations. These advantages are attained, furthermore, without any appreciable increase in manufacturing costs over the structure of said pending patent application.

FIG. 1 is a vertical sectional view of an embodiment of the panel structure of the present invention; and

FIG. 2 is a vertical sectional view of another embodiment of the panel structure of this invention showing a septum extending across the honeycomb core.

As stated hereinabove, the acoustical panel structure of the present invention has a number of features in common with the panel structure of pending patent application Ser. No. 98,794. To the extent, therefore, that the structure of this invention comprises elements in common with the structure of said pending application, the subject matter of the application is incorporated herein by reference.

Referring, now, to FIG. 1 of the drawing, the embodiment of the panel structure illustrated and designated generally by reference numeral 10, comprises a cellular body portion or core 12 having thin, substantially homogeneous mats 14 and 16 secured to opposite sides thereof. The cellular core 12 preferably is a walled structure such a honeycomb formed of cardboard, kraft paper, plastic, a lightweight metal, or the like. The thickness of the core 12 can range from about 1/4 inch to about 2 inches, preferably from about 3/8 inch to about 3/4 inch, and most preferably about 5/8 inch. The size of the cells comprising the core 12 can range from about 1/4 inch to about 3/4 inch, with a cell diameter size of about 3/8 inch being preferred.

The mats 14 and 16 are secured to the end edges of the walls which define the cells of the honeycomb core 12. As shown, the inner surface 14a and the inner surface 16a of the mats 14 and 16 lie in parallel planes and no portion of the inner surfaces 14a and 16a extends into the cells comprising the core 12. The mats 14 and 16 advantageously are in the form of thin, dense, sound transmitting, substantially homogeneous, non-woven glass fiber sheets having a thickness of about 0.010 to about 0.020 inch, preferably about 0.015 to about 0.018 inch, and a density of about 8 to about 12 lbs. per cubic foot, preferably about 9 about 10 lbs. per cubic foot. The glass fibers comprising the mats 14 and 16 arranged in a random pattern and are bonded together with a residous binder. The density and composition of the mats act to resist penetration by contaminants, and provide a smooth surface which promotes adhesion and film continuity.

The unique advantages of the panel structure of the present invention, particularly from the standpoint of its significantly greater noise reduction coefficient over that of the panel structure of said pending patent application, are attained by applying a glass fiber layer or sheet 20 on the outer surface of one of the mats 14 or 16. As illustrated in the drawing, the sheet 20 is secured to the outer surface of the mat 16. The thickness of sheet 20 can be about 1/16 inch to about 3/16 inch, with a thickness of about 1/8 inch being preferred. The density of the sheet can be about 6 to about 12 lbs/ft.sup.3, preferably about 10 lbs/ft.sup.3, more or less.

The sheet 20 advantageously is provided with a coating or layer 22 of a decorative material. The coating or layer 22 can comprise a film of a latex based paint, or, preferably, a sheet formed of open-weave natural or synthetic fabrics, or blends thereof. Especially preferred are fabrics formed of woven, spun or filament plastics such as vinyls, polyesters, polypropylenes, nylons, and glass fibers. The thickness of the decorative coating or layer 22 can be about 2 to about 8 mils, desirably about 4 to about 5 mils. In those instances where the layer 22 is formed of a fabric, the layer 22 advantageously is wrapped around the edges of the structure, and the ends 22a--22a of the layer 22 are secured along the margins of the outer surface of the mat 14. This arrangement results in an integrated, lightweight, yet flexible, high-strength structure having a finished, highly attractive appearance.

In the embodiment of the invention shown in FIG. 2 of the drawing, the panel structure, designated generally by reference numeral 30, a septum 32 is incorporated into the honeycomb core 34. The core 24, like the core 12 of the panel structure 10, has thin glass fiber mats 36 and 38 secured, as by adhesion, to the opposed major surfaces thereof. Also, as in the case of the panel structure 10, the panel structure 30 has a glass fiber sheet 40 secured to one of the mats, namely, mat 38, and a decorative coating or layer 42 is adhered to the sheet 40, and wrapped around the edges of the panel structure as described above with regard to the structure 10.

The septum 32 may be formed of a metal foil such as aluminum or lead foil, chipboard, or it may be made of a synthetic plastic film forming materials such as polyethylenes, vinyls, polyesters, and the like. The septum acts to enhance the sound transmission properties of the panel structure 30, and serves to provide an effective barrier to the passage of dirt ladened air through the panel. The thickness of the septum 32 can be about 0.5 mil to about 5 mils, preferably about 2 to about 3 mils.

The panel structure of the present invention, like the panel structure disclosed in pending application Ser. No. 98,794, can be manufactured in an in-line, continuous, high-speed operation at a fraction of the cost incurred in the manufacture of conventional honeycomb cored structures. The panel structure of this invention is especially adaptable to fabrication in a double facing laminating operation which includes the steps of coating both sides of the honeycomb core with a suitable adhesive, and then applying, simultaneously, the thin glass fiber mats 14 and 16 to the adhesive coated surfaces of the core. The glass fiber sheet 20 can then be applied to an adhesive coated surface of one of the mats. The thusly formed laminated structure can then be passed into an oven heated to a temperature of from about 90.degree. to 140.degree. F. to cure the adhesive. From the oven, the structure is passed through a cooling station, and then between nip rollers to assure proper adhesion between the core and the mats, and the layer 20. The thusly formed panel structure can then be cut to size and stacked. Cut panel sizes can range from 2'.times.2' to 5'.times.10'. The entire operation can be performed at a line speed of about 40-50 ft/min. If desired, the cut panels can be provided with segments or patches of fastener means such as is disclosed in said pending patent application.

The panel structures of the present invention have, as stated, a noise reduction coefficient of upwards of 75. The flame spread of the panels is less than 25, which qualifies the panels for a Class A fire rating.

While for purposes of illustration representative embodiments of the invention have been shown and described, other embodiments of the invention may become apparent to those skilled in the art upon reference to this disclosure without departing from the spirit and scope of the invention.