Asbestos-free joint compounds

Abstract

A joint compound which is preferably asbestos-free, for use in finishing joints between wallboards, comprising a filler, a binder, and any two or all three of a water-holding agent; a slip-inducing colloid; and a non-swelling clay having sufficient pseudoplasticity to render the composition non-leveling.

What is claimed is: 
     
       1. A composition which when mixed with water forms a non-leveling joint compound having properties suitable for use in finishing joints between wallboards .[.even when.]..Iadd., said composition being .Iaddend.free of asbestos fibers.[.,.]. .Iadd.and .Iaddend.comprising the following ingredients in amounts based on the total dry weight of the composition: a filler selected from the group consisting of calcium carbonate and calcium sulfate in an amount of between about 37 and 92 percent;   a binder in an amount of between about 1 and 7 percent;   attapulgus clay in an amount of between about 0.5 and 6 percent; and   at least one ingredient selected from the group consisting of;   a water-holding agent in an amount of between about 0.1 and 2.0 percent; and   a slip-inducing colloid in an amount of between about 0.1 and 2.0 percent selected from the group consisting of modified montmorillonite clay gel and xanthan gum, .Iadd.   said joint compound being characterized by having desirable working properties including non-leveling and slip properties which heretofore were achieved through the addition of asbestos and which properties are provided herein by substituting attapulgus clay to provide the pseudoplasticity necessary for obtaining said desired properties while avoiding the health hazards associated with the use of asbestos. .Iaddend.   
     
     
       2. The composition as defined in claim 1, wherein said water-holding agent is sodium carboxymethylcellulose having a degree of substitution less than about 0.7. 
     
     
       3. The composition as defined in claim 1, comprising both said water-holding agent and said slip-inducing colloid. 
     
     
       4. The composition as defined in claim 3, wherein said slip-inducing colloid is modified montmorillonite clay gel. 
     
     
       5. The composition as defined in claim 3, wherein said slip-inducing colloid is xanthan gum. 
     
     
       6. The composition as defined in claim 3, wherein said water-holding agent is sodium carboxymethylcellulose having a degree of substitution less than about 0.7. 
     
     
       7. The composition as defined in claim 1, where said filler is calcium carbonate. 
     
     
       8. The composition as defined in claim 1, wherein said filler is calcium sulfate dihydrate. 
     
     
       9. The composition as defined in claim 1, wherein said filler is calcium sulfate hemihydrate. 
     
     
       10. The composition as defined in claim 1, wherein said binder is a polyvinyl acetate emulsion. 
     
     
       11. A ready-mixed non-leveling joint compound having properties suitable for use in coating joints between gypsum wallboards .[.even when.]. .Iadd.said composition being .Iaddend.free of asbestos fibers.[.,.]. .Iadd.and .Iaddend.comprising the following ingredients in amounts based on the total dry weight of the composition: water;   a filler selected from the group consisting of calcium carbonate and calcium sulfate in an amount of between about 37 and 92 percent;   a polyvinyl acetate emulsion in an amount of between about 1 and 7 percent;   a slip-inducing colloid in an amount of between about 0.1 and 2.0 percent selected from the group consisting of modified montmorillonite clay gel and xanthan gum; and   attapulgus clay in an amount of between about 0.5 and 6.0 percent.Iadd., .Iaddend..Iadd.   said joint compound being characterized by having desirable working properties including non-leveling and slip properties which heretofore were achieved through the addition of asbestos and which properties are provided herein by substituting attapulgus clay to provide the pseudoplasticity necessary for obtaining said desired properties while avoiding the health hazards associated with the use of asbestos. .Iaddend.   
     
     
       12. The composition as defined in claim 11, additionally comprising sodium carboxymethylcellulose in an amount of between about 0.1 and 2.0 percent.