High pressure decorative laminate having registered color and embossing

Abstract

A decorative high pressure laminate having registered color and embossing is produced by effecting simultaneous embossing and laminating using a three dimensional press plate acting against an overlay sheet containing high flow melamine resin and pigment, so that during the pressing operation the resin and pigment flows laterally from the high pressure areas to the low pressure areas with the result that the underlying print sheet is visible through the overlay sheet in the high pressure areas while the pigment in the overlay sheet in the low pressure areas mask the print sheet.

What is claimed is: 
     
       1. A method of forming a unitary decorative laminate having registered color and embossing comprising: 
     
     
       A. assembling in a stack from the bottom up (1) backing means for said decorative laminate,   (2) a thermosetting resin impregnated fibrous print sheet provided with a first color,   (3) a fibrous overlay sheet substantially uniformly impregnated with an opacifying mixture of a thermosetting resin impregnating solution having dispersed therein finely divided pigment of a color contrasting with said first color, said pigment being retained substantially on the fibers of said overlay sheet and .Iadd.not being bound to the cellulose of the paper, and .Iaddend.   (4) a sculptured pressing plate die having a surface with high areas and low areas capable of being impressed into the uppermost of said fibrous sheets with said high and low areas adjacent said overlay sheet, and means to prevent said sculptured pressing plate die from sticking to said overlay sheet during lamination;   
     
     
       B. applying to the upper and lower surfaces of said assembly sufficient heat and pressure to cure said resins to produce said unitary embossed decorative high pressure laminate by (1) effecting a lamination of said fibrous sheets together with each other and with said backing means,   (2) imparting the sculptured surface of said die to the uppermost of fibrous sheets and   (3) effecting lateral flow of said opacifying mixture of said thermosetting resin and said pigment on said overlay sheet from the debossed portions of the surface of said laminate to the embossed portions of said laminate .Iadd.causing a separation of colors .Iaddend.so that said first color is visible in said debossed portions and said contrasting color of said finely devided pigment is visible in said embossed portions; and   
     
     
       C. stripping said sculptured die from the resultant laminated assembly so as to provide said laminate having areas of registered color and embossing. 
     
     
       2. A method in accordance with claim 1 for forming a high pressure decorative laminate, wherein said backing means comprise phenolic resin impregnated core sheets, wherein said print sheet comprises a melamine resin impregnated α-cellulose paper, and said overlay sheet comprises melamine resin impregnated α-cellulose paper. 
     
     
       3. A method in accordance with claim 2 wherein said means to prevent said sculptured pressing plate die from sticking to said overlay sheet comprises a separate release sheet. 
     
     
       4. A method in accordance with claim 2 wherein said pressing plate die comprises a thin, embossed, impregnated separator sheet having a non-stick facing. 
     
     
       5. A method in accordance with claim 2 wherein in step B said assembly is pressed at approximately 800-1600 psi at a temperature on the order of 230°-310° F. 
     
     
       6. A method in accordance with claim 2 wherein said α-cellulose overlay sheet has a melamine resin content in the 65-70% range, a volatile content of 6-10% and a flow of 7-35%. 
     
     
       7. A method in accordance with claim 6 for forming a high pressure decorative laminate simulating leather, wherein said first color is pale yellow and wherein said finely divided pigment comprises opacifying pigments providing a dark brown color and present in a quantity of 1-5% based on the weight of the melamine resin impregnating solution. .Iadd. 8. A method in accordance with claim 1 wherein said first color is darker than the color of said pigment. .Iaddend.