Method for embossing mineral fiber board

Claim 1

Method for embossing mineral fiber sheet wherein said sheet is composed of: (a) from about 75 to about 85% by weight mineral material, said mineral material being composed of; (i) from about 20 to about 85% mineral fibers; (ii) from 0 to about 50% perlite; (iii) from 0 to about 10% of other mineral materials; b. from about 15 to about 25% of a binding system, said binding system being composed of: (i) from about 5 to about 15% by weight cellulosic fibers; (ii) from about 10 to about 20% of a reactivatable binding agent; (c) said sheet having a thickness of from about 1/2 inch to about 2 inches and a density of from about 15 pounds to about 25 pounds: said method comprising the steps of wetting at least one side of the sheet surface with from about 7 to about 15 pounds of water per thousand square feet of board surface and thereafter positioning the sheet on a stationary platen subjecting the sheet surface to treatment with a stationary reciprocating press having a design forming member having a temperature of from about 550° to about 750° F and said design forming member being applied for a period of from about 0.1 seconds to about 2 seconds at a pressure sufficient to deform the surface whereby a permanently embossed pattern is obtained on the surface of the mineral fiber sheet.