Plaster boards and methods for making them

Abstract

One aspect of the disclosure is a plaster board having a first edge and an opposed second edge, and a third edge and an opposed fourth edge. The plaster board includes a first layer of hardened plaster material including a first surface and an opposed second surface, and a second layer of hardened plaster material including a first surface and an opposed second surface. The second layer of hardened plaster material is stacked against the first layer such that their first surfaces face one another. The first layer and the second layer together define the first, second, third, and fourth edges of the plaster board. The plaster board also includes a viscoelastic polymer disposed between the first surfaces of the first and second layers of hardened plaster material. The viscoelastic polymer does not extend substantially to the first, second, third, and fourth edges of the plaster board.

What is claimed is: 
     
         1 . A plaster board having a first edge and an opposed second edge, and a third edge and an opposed fourth edge, the plaster board comprising:
 a first layer of hardened plaster material comprising a first surface and an opposed second surface;   a second layer of hardened plaster material comprising a first surface and an opposed second surface, the second layer of hardened plaster material being stacked against the first layer such that their first surfaces face one another, the first layer and the second layer together defining the first, second, third, and fourth edges of the plaster board; and   a viscoelastic polymer disposed between the first surface of the first layer of hardened plaster material and the first surface of the second layer of hardened plaster material, the viscoelastic polymer not extending substantially to the first, second, third, and fourth edges of the plaster board.   
     
     
         2 . The plaster board of  claim 1 , wherein the second surface of the second layer of hardened plaster material is tapered along one or more of the first, second, third and fourth edges of the plaster board. 
     
     
         3 . The plaster board of  claim 1 , wherein the viscoelastic polymer does not extend to within one inch of one or more of the first, second, third, and fourth edges of the plaster board. 
     
     
         4 . The plaster board of  claim 1 , wherein the viscoelastic polymer does not extend to within one inch inches of two or more of the first, second, third, and fourth edges of the plaster board. 
     
     
         5 . The plaster board of  claim 1 , wherein the viscoelastic polymer does not extend to within one inch, two inches, or three inches of the third edge of the plaster board, and does not extend to within one inch of the fourth edge of the plaster board 
     
     
         6 . The plaster board of  claim 1 , wherein the viscoelastic polymer does not extend to within one inch of three or more of the first, second, third, and fourth edges of the plaster board. 
     
     
         7 . The plaster board of  claim 1 , wherein the viscoelastic polymer does not extend to within one inch of each of the first, second, third, and fourth edges of the plaster board. 
     
     
         8 . The plaster board of  claim 1 , further comprising
 adhesive tape disposed along one or more of the first, second, third, and fourth edges of the plaster board, the adhesive tape binding the second surface of the second layer of hardened plaster material to the second surface of the first layer of hardened plaster material such that the adhesive tape holds the first layer of hardened plaster in place with respect to the second layer of hardened plaster material.   
     
     
         9 . The plaster board of  claim 8 , further comprising:
 a first liner disposed on the second surface of the first layer of hardened plaster material; and   a second liner disposed on the second surface of the second layer of hardened plaster material,   wherein the adhesive tape is adhered to the first liner and to the second liner along the one or more of the first, second, third, and fourth edges of the plaster board.   
     
     
         10 . The plaster board of  claim 1 , further comprising:
 a structural adhesive material disposed between the first surface of the first layer of hardened plaster material and the first surface of the second layer of hardened plaster material, along one or more of the first, second, third, and fourth edges of the plaster board, laterally between the viscoelastic polymer and the one or more of the first, second, third, and fourth edges, the structural adhesive material being a substantially less viscoelastic material than the viscoelastic polymer.   
     
     
         11 . The plaster board of  claim 10 , wherein the structural adhesive material is disposed along the third edge and the fourth edge of the plaster board, laterally between the viscoelastic polymer and the third edge, and laterally between the viscoelastic polymer and the fourth edge. 
     
     
         12 . The plaster board of  claim 10 , wherein the structural adhesive material is disposed along the first edge and the second edge of the plaster board, laterally between the viscoelastic polymer and the first edge, and laterally between the viscoelastic polymer and the second edge. 
     
     
         13 . The plaster board of  claim 10 , wherein the structural adhesive material extends substantially to the one or more of the first, second, third, and fourth edges of the plaster board. 
     
     
         14 . The plaster board of  claim 10 , wherein the structural adhesive material contacts the viscoelastic polymer along the one or more of the first, second, third, and fourth edges of the plaster board. 
     
     
         15 . The plaster board of  claim 10 , wherein the structural adhesive has a shear modulus that is at least 10 MPa greater than the shear modulus of the viscoelastic polymer. 
     
     
         16 . The plaster board of  claim 1 , wherein at least 50 percent of the area of the first surfaces of the first layer of hardened plaster material or the second layer of hardened plaster material is covered by the viscoelastic polymer. 
     
     
         17 . The plaster board of  claim 1 , wherein no more than 98 percent of the area of the first surfaces of the first layer of hardened plaster material or the second layer of hardened plaster material is covered by the viscoelastic polymer. 
     
     
         18 . The plaster board of  claim 1 , wherein the viscoelastic polymer has an elastic modulus in the range of 10 kPa to 100 MPa. 
     
     
         19 . A method of forming any of the plaster boards of  claim 1 , the method comprising:
 applying the viscoelastic polymer over the first surface of the first layer of hardened plaster material and/or over the first surface of the second layer of hardened plaster material such that the viscoelastic polymer does not extend substantially to the first, second, third, and fourth edges of the plaster board; and   adhering the first surface of the first layer of hardened plaster material to the first surface of the second layer of hardened plaster using at least the viscoelastic polymer.   
     
     
         20 . The method of  claim 19 , further comprising:
 applying a structural adhesive material between the first surface of the first layer of hardened plaster material and the first surface of the second layer of hardened plaster material along one or more of the first, second, third, and fourth edges of the plaster board such that, after the viscoelastic polymer is applied, the structural adhesive material is laterally between the viscoelastic polymer and the one or more of the first, second, third, and fourth edges, the structural adhesive material being a substantially less viscoelastic material than the viscoelastic polymer.