Patent No. U.S. 7,238,391 B2
Valspar has received a patent for a method of making a fiberboard cement siding product, comprised of providing a fiberboard cement substrate, coating a first major surface of the fiberboard cement substrate with a sealer; coating the exposed surface of the sealer with a primer; coating the exposed surface of the primer with a decorative coating; coating the exposed surface of the decorative coating with a topcoat layer comprised of a polyurethane dispersion; and curing the topcoat layer to provide a mar and abrasion resistant coated fiberboard cement siding product; wherein the curing step comprises a thermal curing process that does not expose the siding to a board surface temperature in excess of 100°C, wherein the fiberboard cement substrate has a density of at least 1 g/cm3 and comprises wood pulp, silica and cement, and the outer topcoat layer has a dry thickness of at least 8 microns.