Underlayment for surface coverings and methods of making the same

Abstract

An underlayment for surface covering, such as flooring, is described wherein the underlayment includes at least one polymeric foam layer having a top surface and a bottom surface and at least one felt layer located on either the top surface or bottom surface of the polymeric foam layer. Methods to reduce or control sound transmission and/or sound reflection of surface coverings like flooring products is also described wherein the underlayment is installed beneath the surface covering.

What is claimed is:  
     
         1 . An underlayment comprising a polymeric foam layer having a top surface in contact with a surface covering and a bottom surface; and a felt layer having a top surface and a bottom surface, located below the bottom surface of said polymeric foam layer and said bottom surface is in contact with a sub-floor or substrate.  
     
     
         2 . The underlayment of  claim 1 , wherein said polymeric foam layer is a thermoplastic foam layer.  
     
     
         3 . The underlayment of  claim 1 , wherein said polymer foam layer has a thickness of from about 20 to about 120 mils.  
     
     
         4 . The underlayment of  claim 1 , wherein said polymeric foam layer has a thickness of from about 40 to about 100 mils.  
     
     
         5 . The underlayment of  claim 1 , wherein the polymeric foam layer comprises at least one polymer selected from polyvinyl chloride, polyurethane, polyvinyl acetate, polyvinyl alcohol, vinyldiene resin, polyethylene, styrene, polypropylene, co-polymers thereof, or combinations thereof.  
     
     
         6 . The underlayment of  claim 1 , wherein the polymeric foam layer comprises an activated blowing agent selected from azodicarbonamide.  
     
     
         7 . The underlayment of  claim 1 , wherein the thickness of the felt layer is from about 10 to about 35 mils.  
     
     
         8 . The underlayment of  claim 1 , wherein said polymeric foam layer comprises at least one vinyl containing polymer or co-polymer and at least one activated blowing agent.  
     
     
         9 . The underlayment of  claim 1 , wherein said polymeric foam layer further comprises at least one plasticizer, extender grade resin, or both.  
     
     
         10 . The underlayment of  claim 9 , wherein said surface covering is a laminate floor product.  
     
     
         11 . The underlayment of  claim 1 , wherein said underlayment when installed beneath a laminate flooring has a higher refractive sound insulation compared to a surface covering with no underlayment.  
     
     
         12 . The underlayment of  claim 1 , wherein said polymeric foam layer and said felt layer are affixed together by adhesive.  
     
     
         13 . The underlayment of  claim 1 , wherein said polymeric foam layer is casted onto said felt layer.  
     
     
         14 . The underlayment of  claim 1 , wherein said polymeric foam layer has a density of from about 5 to about 35 lbs/ft 3 .  
     
     
         15 . The underlayment of  claim 1 , wherein said polymeric foam layer has a density of from about 15 to about 25 lbs/ft 3 .  
     
     
         16 . A method to reduce or control sound reflection comprising the steps of installing the underlayment of  claim 1  beneath a surface covering.  
     
     
         17 . The method of  claim 16 , wherein said surface covering is a laminate flooring product.  
     
     
         18 . A method to control or reduce the sound transmission of a flooring product comprising installing the underlayment of  claim 1  beneath said flooring product.  
     
     
         19 . The method of  claim 18 , wherein the sound transmission is impact sound transmission.  
     
     
         20 . The method of  claim 18 , wherein said sound transmission is airborne sound transmission.