Plasterboard composition, preparation of this composition and manufacture of plasterboards

Abstract

A plasterboard composition includes from 55 to 92% of hydratable calcium sulphate; from 0.1 to 5% of mineral and/or refractory fibres; from 3 to 25% of a mineral additive; from 1 to 5% of unexpanded vermiculite; and from 3 to 15% of hydrated alumina.

What is claimed is:  
     
         1 . Plasterboard composition comprising: 
 from 55 to 92% of hydratable calcium sulphate;    from 0.1 to 5% of mineral or refractory fibres;    from 1 to 5% of unexpanded vermiculite; and    from 3 to 15% of hydrated alumina;    from 3 to 25% of a mineral additive consisting essentially of a clayey material, the mineral additive includes an amount of crystalline silica which is at most about 15% by weight of the mineral additive, and an inert mineral supplement compatible with the clayey material and dispersible in the plaster board composition.    
     
     
         2 . The plasterboard composition according to  claim 1 , in which a nature and an amount of the mineral additive are chosen so that the plaster composition contains at most 2% crystalline silica.  
     
     
         3 . The plasterboard composition according to  claim 1 , in which the nature and the amount of the mineral additive are chosen so that the plasterboard composition contains at most 1% cellular crystalline silica.  
     
     
         4 . The plasterboard composition according to  claim 1 , in which the mineral additive comprises kaolin, illite, quartz and dolomite.  
     
     
         5 . The plasterboard composition according to the  claim 4 , in which the mineral additive comprises, in percentages by weight: 
 25% kaolin;    10% illite;    15% quartz; and    50% dolomite.    
     
     
         6 . The plasterboard composition according to  claim 1 , in which the unexpanded vermiculite is micronized.  
     
     
         7 . The plasterboard composition according to  claim 1 , which furthermore includes up to 4% boric acid.  
     
     
         8 . The plasterboard composition according to  claim 2 , which furthermore includes up to 4% boric acid.  
     
     
         9 . The plasterboard composition according to  claim 5 , which furthermore includes up to 4% boric acid.  
     
     
         10 . The plasterboard composition according to  claim 1 , comprising: 
 70 to 80% of hydratable calcium sulphate;    1% of glass fibres;    10 to 15% of the mineral additive consisting essentially of kaolin, illite, quartz and dolomite;    2 to 4% of micronized unexpanded vermiculite;    6 to 10% of hydrated alumina; and    0 to 2% of boric acid.    
     
     
         11 . A plasterboard consisting essentially of a hardened composition according to  claim 1 .  
     
     
         12 . A plasterboard consisting essentially of a hardened composition according to  claim 6 .  
     
     
         13 . A plasterboard consisting essentially of a hardened composition according to  claim 7 .  
     
     
         14 . A plasterboard consisting essentially of a hardened composition according to  claim 10 .  
     
     
         15 . A plasterboard consisting essentially of a hardened composition according to  claim 1 , in which the density is between 800 and 1,000 kg m 3 .  
     
     
         16 . The plasterboard according to  claim 11 , in which at least one of its sides is coated with a reinforcing material based on mineral and/or refractory fibres, or based on cardboard.  
     
     
         17 . The plasterboard according to  claim 16 , in which each of its two sides is coated with a reinforcing material based on glass fibres.  
     
     
         18 . The plasterboard according to  claim 12 , in which at least one of its sides is coated with a reinforcing material based on mineral and/or refractory fibres, or based on cardboard.  
     
     
         19 . The plasterboard according to  claim 18 , in which each of its two sides is coated with a reinforcing material based on glass fibres.  
     
     
         20 . The plasterboard according to  claim 13 , in which at least one of its sides is coated with a reinforcing material based on mineral or refractory fibres, or based on cardboard.  
     
     
         21 . The plasterboard according to  claim 20 , in which each of its two sides is coated with a reinforcing material based on glass fibres.  
     
     
         22 . The plasterboard according to  claim 14 , in which at least one of its sides is coated with a reinforcing material based on mineral or refractory fibres, or based on cardboard.  
     
     
         23 . The plasterboard according to  claim 22 , in which each of its two sides is coated with a reinforcing material based on glass fibres.  
     
     
         24 . A method of preparing a composition according to  claim 1 , comprising mixing the constituents of the composition together in any order.  
     
     
         25 . A method of preparing a composition according to  claim 6 , comprising mixing the constituents of the composition together in any order.  
     
     
         26 . A method of preparing a composition according to  claim 7 , comprising mixing the constituents of the composition together in any order.  
     
     
         27 . A method of preparing a composition according to  claim 10 , comprising mixing the constituents of the composition together in any order.  
     
     
         28 . A continuous process for manufacturing plasterboards, essentially comprising the following steps: 
 mixing the various constituents of the composition according to  claim 1  with water to form a slurry;    depositing the slurry on a reinforcing material, followed by shaping and covering an upper face of the slurry using a second reinforcing material;    where appropriate, shaping edges of the board by moulding the board on profiled bands;    setting the composition on a manufacturing line that runs along a conveyor belt;    cutting the set composition at the end of the line into predetermined lengths; and;    drying of the boards obtained.    
     
     
         29 . A continuous process for manufacturing plasterboards, essentially comprising the following steps: 
 mixing the various constituents of the composition according to  claim 6  with water to form a slurry;    depositing the slurry on a reinforcing material, followed by shaping and covering an upper face of the slurry using a second reinforcing material;    where appropriate, shaping edges of the board by moulding the board on profiled bands;    setting the composition on a manufacturing line that runs along a conveyor belt;    cutting the set composition at the end of the line into predetermined lengths; and;    drying of the boards obtained.    
     
     
         30 . A continuous process for manufacturing plasterboards, essentially comprising the following steps: 
 mixing the various constituents of the composition according to  claim 7  with water to form a slurry;    depositing the slurry on a reinforcing material, followed by shaping and covering an upper face of the slurry using a second reinforcing material;    where appropriate, shaping edges of the board by moulding the board on profiled bands;    setting the composition on a manufacturing line that runs along a conveyor belt;    cutting the set composition at the end of the line into predetermined lengths; and;    drying of the boards obtained.    
     
     
         31 . A continuous process for manufacturing plasterboards, essentially comprising the following steps: 
 mixing the various constituents of the composition according to  claim 10  with water to form a slurry;    depositing the slurry on a reinforcing material, followed by shaping and covering an upper face of the slurry using a second reinforcing material;    where appropriate, shaping edges of the board by moulding the board on profiled bands;    setting the composition on a manufacturing line that runs along a conveyor belt;    cutting the set composition at the end of the line into predetermined lengths; and;    drying of the boards obtained.