Polyurethane coated resilient surface covering having improved fidelity of texture and process of manufacture

Abstract

Mechanically embossed resilient surface coverings having superior textural fidelity are prepared by mechanically embossing a polyurethane coated floorcovering before the polyurethane is cured. The mechanical embossing is conducted when the polyurethane is dry and the underlying plastic layer and the polyurethane are softened by heating. After the mechanical embossing step, the polyurethane is cured using ultraviolet (UV) light. The product can be cooled before or after UV curing. The invention is applicable to a variety of resilient surface covering products including floor and wall coverings which otherwise have a wearlayer which can be softened by heating. This includes surface coverings having the full range of decorative effects available in the art, including surface coverings which also have been, for example, chemically embossed, mechanically embossed, chemically and mechanically embossed or not embossed at all prior to application of the process of the invention.

What is claimed is:  
     
         1 . A surface covering which comprises: 
 a) a surface covering base having a thermoplastic wearlayer, and    b) a cured polyurethane layer overlaying the wearlayer and mechanically embossed with a surface texture wherein the surface texture is mechanically embossed in the polyurethane layer when the wearlayer and the polyurethane layer are in a softened state and the polyurethane layer is in a dry uncured state.    
     
     
         2 . The surface covering of  claim 1  wherein the surface texture is mechanically embossed in the polyurethane layer and the wearlayer.  
     
     
         3 . The surface covering of  claim 1  or  2  wherein the surface covering base is selected from the group consisting of resilient sheet flooring, tile and wall covering.  
     
     
         4 . The surface covering of  claim 1  or  2  wherein the surface covering base is selected from the group consisting of resilient sheet vinyl flooring, laminate flooring, linoleum, vinyl composition tile, solid vinyl tile and luxury vinyl tile.  
     
     
         5 . A surface covering which comprises: 
 a) a substrate,    b) a plastic layer overlaying the substrate, and    c) a cured polyurethane layer overlaying the plastic top layer and mechanically embossed with a surface texture wherein the surface texture is mechanically embossed in the polyurethane layer when the plastic top layer and the polyurethane layer are in a softened state and the polyurethane layer is in a dry uncured state.    
     
     
         6 . The surface covering of  claim 5  wherein the surface texture is mechanically embossed in the polyurethane layer and the plastic top layer.  
     
     
         7 . The surface covering of claims  5  or  6  further comprising one or more layers of printed ink between the substrate and the plastic top layer, between the plastic top layer and the polyurethane layer or between the substrate and the plastic top layer and between the plastic top layer and the polyurethane layer.  
     
     
         8 . The surface covering of claims  5  or  6  further comprising a foamed plastic layer between the substrate and the plastic top layer.  
     
     
         9 . The surface covering of  claim 8  further comprising one or more layers of printed ink between the foamed plastic layer and the plastic top layer.  
     
     
         10 . A surface covering which comprises: 
 a) a sheet substrate,    b) a foamed and chemically embossed plastic layer overlaying the sheet substrate,    c) a plastic top layer overlaying the foamed plastic layer,    d) a cured polyurethane layer overlaying the plastic top layer and mechanically embossed with a surface texture wherein the surface texture is mechanically embossed in the polyurethane layer when the plastic top layer and the polyurethane layer are in a softened state and the polyurethane layer is in a dry uncured state.    
     
     
         11 . The surface covering of  claim 10  wherein the surface texture is mechanically embossed in the polyurethane layer and the plastic top layer.  
     
     
         12 . The surface covering of claims  10  or  11  further comprising one or more layers of printed ink between the plastic layer and the plastic top layer.  
     
     
         13 . The surface covering of  claim 12  wherein the ink is printed in a pattern or a design.  
     
     
         14 . A method of making a surface covering which comprises the sequential steps of: 
 a) coating the wearlayer of a surface covering base with an ultraviolet curable polyurethane layer,    b) drying the ultraviolet curable polyurethane layer,    c) heating to soften the wearlayer and the ultraviolet curable polyurethane layer,    d) mechanically embossing the ultraviolet curable polyurethane layer,    e) curing the ultraviolet curable polyurethane layer.    
     
     
         15 . The method of  claim 14  wherein the surface covering is cooled prior to curing the ultraviolet curable polyurethane layer.  
     
     
         16 . The method of  claim 14  wherein the surface covering is cooled following curing of the ultraviolet curable polyurethane layer.  
     
     
         17 . The method of  claim 14  wherein the surface covering base is selected from the group consisting of sheet flooring, tile and wall covering.  
     
     
         18 . The method of  claim 14  wherein the surface covering base is selected from the group consisting of sheet vinyl flooring, laminate flooring, linoleum, vinyl composition tile, solid vinyl tile and luxury vinyl tile.  
     
     
         19 . The method of  claim 14  wherein the wearlayer and the ultraviolet curable polyurethane layer are mechanically embossed.  
     
     
         20 . A method of making a surface covering which comprises the sequential steps of: 
 a) coating a substrate with a plastic top layer,    b) heating to fuse the plastic top layer with the substrate,    c) cooling the surface of the plastic top layer to a temperature from about 90° C. to about 15° C.,    d) coating the surface of the plastic top layer with an ultraviolet curable polyurethane layer,    e) drying the ultraviolet curable polyurethane layer,    f) heating to soften the plastic top layer and the ultraviolet curable polyurethane layer,    g) mechanically embossing the plastic top layer and the ultraviolet curable polyurethane layer,    h) curing the ultraviolet curable polyurethane layer.    
     
     
         21 . The method of  claim 20  wherein the surface covering is cooled prior to curing the ultraviolet curable polyurethane layer.  
     
     
         22 . The method of  claim 20  wherein the surface covering is cooled following curing of the ultraviolet curable polyurethane layer.  
     
     
         23 . The method of  claim 20  further comprising printing an ink on the sheet substrate prior to coating with the plastic top layer.  
     
     
         24 . The method of  claim 20  further comprising printing an ink on the plastic top layer prior to heating to fuse the plastic top layer.  
     
     
         25 . The method of claims  23  or  24  wherein the ink is printed in a pattern or a design.  
     
     
         26 . A method of making a surface covering which comprises the sequential steps of: 
 a) coating a sheet substrate with a plastic layer containing a foaming agent,    b) heating to gel the plastic layer without activating the foaming agent,    c) printing in a pattern or design on the gelled plastic layer with an ink containing a chemical suppressant,    d) coating with a plastic top layer,    e) heating to activate the foaming agent and fuse the layers with one another and the sheet substrate,    f) cooling the surface of the plastic top layer to a temperature from about 90° C. to about 15° C.,    g) coating the surface of the plastic top layer with an ultraviolet curable polyurethane layer,    h) drying the ultraviolet curable polyurethane layer,    i) heating to soften the plastic top layer and the ultraviolet curable polyurethane layer,    j) mechanically embossing the plastic top layer and the ultraviolet curable polyurethane layer,    k) curing the ultraviolet curable polyurethane layer.    
     
     
         27 . The method of  claim 26  wherein the surface covering is cooled prior to curing the ultraviolet curable polyurethane layer.  
     
     
         28 . The method of  claim 26  wherein the surface covering is cooled after curing the ultraviolet curable polyurethane layer.  
     
     
         29 . The method of  claim 26  wherein an additional layer of ink which does not contain a chemical suppressant is printed following printing with an ink containing a chemical suppressant.