Abstract: Mold- and moisture-resistant gypsum boards and methods for making them are disclosed, the method comprising applying a slurry that forms a gypsum core to an upper or a lower facing sheet impregnated with a thermoset resin (e.g., a phenol-formaldehyde resin) in an amount effective to (i) allow water vapor passage through the facing sheet when the thermoset resin is in its uncured state and (ii) provide mold and moisture resistance to the facing sheet when the thermoset resin is in its cured state and heating sufficiently to cure said resin and dry said gypsum core, thereby yielding said gypsum board.

Abstract: Mold- and moisture-resistant gypsum boards and methods for making them are disclosed, the method comprising applying a slurry that forms a gypsum core to an upper or a lower facing sheet impregnated with a thermoset resin (e.g., a phenol-formaldehyde resin) in an amount effective to (i) allow water vapor passage through the facing sheet when the thermoset resin is in its uncured state and (ii) provide mold and moisture resistance to the facing sheet when the thermoset resin is in its cured state and heating sufficiently to cure said resin and dry said gypsum core, thereby yielding said gypsum board.

Abstract: Mold- and moisture-resistant gypsum boards and methods for making them are disclosed, the method comprising applying a slurry that forms a gypsum core to an upper or a lower facing sheet impregnated with a thermoset resin (e.g., a phenol-formaldehyde resin) in an amount effective to (i) allow water vapor passage through the facing sheet when the thermoset resin is in its uncured state and (ii) provide mold and moisture resistance to the facing sheet when the thermoset resin is in its cured state and heating sufficiently to cure said resin and dry said gypsum core, thereby yielding said gypsum board.

Abstract: The cure rate of phenol-aldehyde resins is accelerated by conjoint use of a cyclic carbonate cure accelerant and an amine cure accelerant. The cure rate is accelerated still further by addition of a resorcinol source to resin comprising a cyclic carbonate and an amine cure accelerator. Also, cured resins made in accordance with the method.

Abstract: A low molecular weight lignin fraction having a pre-selected molecular weight range prepared from lignin solution by ultrafiltration. The invention also relates to phenol-formaldehyde resin modified by the lignin fraction, adhesive comprising the modified resin, and a method for producing the lignin fraction and the resin.

Abstract: A plywood-patching composition is provided based on a noncellular polyurethane elastomer prepared by reacting a polyether or polyester polyol with a polyisocyanate in the presence of a catalytic amount of a substantially anhydrous potassium salt of a carboxylic acid having from 2 to about 20 carbon atoms, and process for preparing same. The catalysts utilized are relatively non-toxic, yet they promote rapid polymerization with essentially no foaming for a wide variety of non-cellular polyurethane elastomeric applications, particularly in plywood-patch applications where even small amounts of foaming is deleterious to the properties thereof.