Patent Publication Number: US-2023139624-A1

Title: Building Board with Acoustical Foam

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/984,716, filed Aug. 4, 2020, which is a continuation of U.S. patent application Ser. No. 16/031,444, filed Jul. 10, 2018, now U.S. Pat. No. 10,731,337, which is. continuation of U.S. patent Ser. No. 13/837,109, filed Mar. 15, 2013, each of which is hereby incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     This disclosure relates to a building board construction. More specifically, the present invention relates to a building board with an acoustical foam. 
     BACKGROUND OF THE INVENTION 
     Building board, also known as wallboard, plasterboard, or drywall, is one of the most commonly used building components in the world today. Building board is frequently used within the interior of a dwelling, where it functions both as a finished wall covering and as a structural room partition. Building board can also be used on the exterior of a dwelling, where it serves as a sheathing to provide weather protection and insulation. Building board can also be used as an interior facing for other structures as well, such as stairwells, elevator shafts, and interior ducting. 
     One particularly popular form of building board is known as gypsum board. Gypsum board is constructed by depositing a layer of cementitious gypsum slurry between two opposing paper liners. Gypsum slurry is the semi-hydrous form of calcium sulfate and has many physical characteristics that make it suitable for use as a building component. For example, gypsum boards generally have a smooth external surface, a consistent thickness, and allow for the application of finishing enhancements, such as paint. Gypsum board is also desirable because it provides a degree of fire resistance and sound abatement. 
     An example of a paper-covered gypsum board is disclosed in U.S. Pat. No. 2,806,811 to Von Hazmburg. Von Hazmburg discloses a board that primarily consists of a thick gypsum core that is encased in a fibrous envelope consisting of both a manila sheet and a newsprint sheet. These sheet layers can be made from a conventional multi-cylinder paper making process. 
     Another popular form of building board is known as glass reinforced gypsum (GRG) board. An example of one such board is disclosed in U.S. Pat. No. 4,265,979 to Baehr et. al. Baehr discloses a building board constructed from opposing glass fiber mats with an intermediate gypsum core. This construction provides a hardened external surface and is an improvement over earlier paper faced boards. 
     Yet another type of gypsum board is disclosed in commonly owned U.S. Pat. No. 4,378,405 to Pilgrim. Pilgrim discloses a GRG board that is faced on one or both sides with a porous, nonwoven glass mat. The glass mat of Pilgrim is fully embedded into the slurry core. This is accomplished by vibrating the gypsum slurry to cause it to pass through the porous openings in the mat. Embedding the mat within the core as taught in Pilgrim results in a thin film of slurry being formed on the outer surface of the board. Building boards with this construction are referred to as embedded glass reinforced gypsum (EGRG) boards. 
     These various building board constructions offer many beneficial characteristics. However, none of these constructions provide for increased acoustical properties. As a result, these boards offer little, if any sound absorption or insulation, they act as a sound barrier. Sound absorption and insulation are especially important when the building board is used as a room partition or even as an exterior building component. Thus, there exists a need in the art for building boards with increased acoustical properties. More specifically, there is a need in the art for a board that absorbs sound waves. The present invention is aimed at achieving these and other objectives. 
     SUMMARY OF THE INVENTION 
     The building boards of the present disclosure have several important advantages. In particular, the disclosed building boards provide increase sound absorption without sacrificing any structural characteristics of the board. 
     A further advantage is realized by providing increased acoustical properties via the inclusion of a polymer sheet within the core of the building board. 
     Still yet another possible advantage of the present system is achieved by incorporating a polymer sheet via a continuous manufacturing method, thereby enabling the building board of the present disclosure to be manufactured quickly and inexpensively. 
     Another advantage of the present system is attained by including a series of sound absorbing polymeric cubes within the core of the building board. 
     Still yet another possible advantage of the present system is achieved by incorporating polymeric cubes or as a powdered material via a continuous manufacturing method, thereby enabling the building board of the present disclosure to be manufactured quickly and inexpensively. 
     A further advantage is recognized by incorporating sound absorbing materials into a gypsum building board via a continuous manufacturing method. 
     Various embodiments of the invention may have none, some, or all of these advantages. Other technical advantages of the present invention will be readily apparent to one skilled in the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present disclosure and its advantages, reference is now made to the following descriptions, taken in conjunction with the accompanying drawings, in which: 
         FIG.  1    is a diagram of one possible manufacturing process for the building boards of the present disclosure. 
         FIG.  2    is a diagram of another possible manufacturing process for the building boards of the present disclosure. 
         FIG.  3    is a diagram of another possible manufacturing process for the building boards of the present disclosure. 
         FIG.  4    is a cross sectional view of an embodiment of the building board of the present disclosure. 
         FIG.  5    is a cross sectional view of an alternative embodiment of the building board of the present disclosure. 
         FIG.  6    is a cross sectional view of an alternative embodiment of the building board of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     The present disclosure relates to a building board with enhanced acoustical properties. In one possible embodiment, the board is a gypsum board with opposing facing sheets and an intermediate set gypsum core. An opened celled polymeric sheet is formed within the gypsum core and gives the resulting board enhanced sound absorption. In an alternative embodiment, individual pieces of polymeric foam are used instead of the polymeric sheet. Also disclosed are various manufacturing methods whereby boards with enhanced acoustical properties can be formed in a continuous process. The various components of the present disclosure, and the manner in which they interrelate, are described in greater detail hereinafter. 
       FIGS.  1 - 3    illustrate various production lines ( 34   a ,  34   b , and  34   c ) for constructing the building boards of the present disclosure.  FIGS.  4 - 6    are cross sectional views of various board constructions ( 20   a ,  20   b ,  20   c ) of the present disclosure. The boards of the present disclosure are generally a core layer  22  of a set gypsum core and opposing paper of fibrous sheets  24 . In the particular embodiment illustrated in  FIG.  4   , board  20   a  has upper and lower mats  24  which are formed from a series of non-woven, randomly aligned inorganic fibers. These mats are preferably porous with interior and exterior faces. Paper facing sheets can also be used and are likewise represented by element  24 . 
     With continuing reference to  FIG.  4   , upper and lower mats  24  are each coated with a layer of dense set slurry  26 . Dense slurry  26  preferably penetrates the upper and lower mats  24 . As a result the exterior surface of each mat  24  is substantially covered by set slurry. Core layer  22  of set gypsum extends fully between and bonds with the upper and lower dense slurry layers  26 . In one embodiment, core slurry layer  22  has a density that is less than the density of the upper and lower dense slurry layers  26 . 
     The enhanced acoustical properties are achieved via the inclusion of a polymer sheet  28  into core slurry layer  22 . In the preferred embodiment, sheet  28  is formed from a melamine resin and is formed into an opened cell foam. Melamine resin is a thermoset polymer. A suitable foam is Basotect® which is manufactured and sold by BASF Corporation. Basotect® foam preferred because it provides a three-dimensional network of slender and easily shaped webs. Basotect® foam also gives the resulting board sound absorption, and chemical and fire resistance. However, the use of other polymer foams is also within the scope of the present disclosures. For a ½ inch thick building board, a polymer sheet  28  of ⅛ inch is preferred. 
     Sound waves entering the cells of the foam are subsequently attenuated and dissipated, thereby giving sheet  28  its sound absorbing characteristics. As such, it is important that the cells of the foam remain free to gypsum slurry during the formation of the board. Polymer sheet  28  is design to be positioned within, but not penetrated by, the core slurry layer  22 . Because polymer sheet  28  does not absorb the slurry layer  22 , and because it preferably extends over the majority of the width of board  20   a , a series of apertures  32  must be formed through the thickness of sheet  28 . Apertures  32  permit the slurry  22  to extend through sheet  28  to thereby fully integrate building panel  20   a . In the absence of apertures  32 , building panel  20   a  would be prone to separation along the boundary of sheet  28 . In the event that polymer sheet  28  could absorb slurry layer  22 , apertures could be eliminated  32 . In the preferred embodiment, the thickness of core layer  22  is substantially larger than the thickness of polymer sheet  28 . 
       FIG.  1    illustrates a gypsum board production line  34   a  that has been modified in accordance with the present disclosure. Production lines  34   a  includes a series of forming tables  36  for supporting building panel  20   a  during its formation. As is known in the art, the mats that form panel are under tension by way of a series of downstream belts. Once panel has been formed, it is passed to a series of board dryers. Dryers function in driving out excess moisture and causing the gypsum slurry to set. This results in the formation of a dried composite panel. 
     As further noted in  FIG.  1   , gypsum board  20   a  is formed from first and second fibrous mats  24  which a volume of gypsum slurry being deposited from a mixer  38 . Paper mats can alternatively be used in place of fibrous mats. In either event, mats  24  are initially stored in large rolls  42  that are unwound in a continuous manufacturing method. A first large roll  42   a  is unwound onto forming table at location  1   a . A dense slurry layer  26  can optionally be deposited over the first mat  24  after it is unrolled beneath a first mixer outlet  44 . Rollers push the dense slurry layer through the mat at location  1   b . Additional slurry is thereafter dispensed from mixer  38  at a second mixer outlet  46  to form core slurry layer  22 . A second large roll  42   b  is ideally positioned downstream of first roll. A second mat  24  is unwound from this roll over top of the deposited gypsum core  22  to create sandwich or panel. The formed panel is noted at location  1   c . Mixer  38  includes a third outlet  48  for supplying a dense slurry layer  26  over the second mat  24 . The polymer sheet  28  is initially stored in a wound roll  52  and is dispensed immediately downstream of second mixer outlet  46 . This positions sheet  28  in approximately the center of core  22 . 
     An alternative production line  34   b  is disclosed in  FIG.  2   . Line  34   b  is the same in all respects to the production line of  FIG.  1   ; however, the rolled polymer sheet  28  is replaced by a hopper  54  containing a plurality of polymer cubes  56  or a volume of a granulated polymer. In the preferred embodiment, cubes of approximately ½ inch are employed. Other shapes and sizes can also be used instead of ½ inch cubes. Basotect® foam can be used to produce polymer cubes  56 . Cubes  56  are dispensed from a hopper  54  to a chute to deliver cubes  56  into core slurry layer  22 . In still yet additional embodiments, the Basotect® foam is added to the slurry in a grated or granular form. 
     The resulting building board  20   b  has a cross section as illustrated in  FIG.  5   . Each of the polymer cubes  56  or granulated material includes an opened cell foam. Cubes  56  or granules are randomly distributed within slurry layer  22 ; however, slurry  22  does not penetrate the individual pieces or cubes  56 . The composite board  20   b  is fully integrated as core layer  22  extends about the individual polymer cubes  56 . In still yet another embodiment, the polymer foam can be grated to form very small bits of foam that agglomerate into a foam fluff. This foam fluff can then be distributed into slurry core  22 . 
     A further embodiment of the production line  34   c  is depicted in  FIG.  3   . This embodiment uses a polymeric sheet  28 , which may have the same construction as the sheet described in connection with  FIG.  1   . However, instead of sheet  28  being delivered into slurry core  22 , it is secured to the lower mat  24  via an adhesive. More specifically, a roll  52  of the polymeric sheet is dispensed over top of mat  24  prior to the mat being delivered to the forming table  36 . The cross sectional view of the resulting building board  20   c  is depicted in  FIG.  6   . As illustrated, sheet  28  is now oriented in facing relation with the first mat  24 . It is also within the scope of the present invention to apply sheet  28  directly to one of the upper or lower dense slurry layers. This would avoid sheet  28  being secured to mat  24 . Either of these embodiments may be used in connection with either of the previously described embodiments. 
     Although this disclosure has been described in terms of certain embodiments and generally associated methods, alterations and permutations of these embodiments and methods will be apparent to those skilled in the art. Accordingly, the above description of example embodiments does not define or constrain this disclosure. Other changes, substitutions, and alterations are also possible without departing from the spirit and scope of this disclosure.