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US 3,935,343 AGranted
Molten salt method of producing fire resistant wood articles
AssigneeUnited States Gypsum Company
InventorHarold W. Nuttall
Life of this patent
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Abstract
Hardboard and other wood articles are made fire resistant by immersing the wood in a molten ammonium phosphate salt batn, preferably monoammonium phosphate.
Claims16
A method for imparting fire resistance to wood articles within a period of 3 minutes which comprises immersing the wood article in molten ammonium phosphate substantially free of water under a pressure of at least about 10 p.s.i.g.
A method for imparting fire resistance to hardboard within a period of three minutes which comprises immersing the hardboard in a molten ammonium phosphate salt bath substantially free of water;
- subjecting the immersed hardboard to a pressure of at least 10 p.s.i.g.;
- removing the hardboard from the molten salt bath;
- and washing the treated hardboard with water.
Dependencies are inferred from the claim text.