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US 8,617,451 B2Granted
Method of producing gypsum building boards
AssigneeBPB Limited
InventorsRobin Fisher, Henri van Damme
Life of this patent
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Abstract
A method of producing gypsum building board, in which there is added, to an aqueous gypsum slurry containing a water swellable clay, a basic water-soluble polymer having preferential affinity for clay. The slurry is allowed to set so as to form a board. The basic water-soluble polymer may be, for example, a polyvinyl alcohol or a polymer consisting essentially of carbon, nitrogen and hydrogen and having amine groups (which may be primary, secondary, tertiary or quaternary) in the polymer backbone and/or in side chains thereof.
Claims15
A method of producing gypsum building board, the method comprising:
- (a) providing an aqueous gypsum slurry containing a water swellable clay, in which there is further added to the gypsum slurry a comb-based copolymer fluidizer and a basic water-soluble polymer having preferential affinity for clay, wherein the basic water-soluble polymer is selected from the group consisting of:
- i) polyvinyl pyrrolidone, ii) polyvinyl alcohol, iii) polyethyleneimine, iv) polyvinyl amine, v) polyallyl amine, vi) poly(diallyldimethylammonium halide);
- and
- (b) allowing a layer of the aqueous gypsum slurry to set so as to form a board.
1 more element
Dependencies are inferred from the claim text.