Ozone and Chemical Resistant Coating for Railway Line Elastomeric Components

Abstract

Elastomeric pads are shown for positioning on top of railroad ties. Pre-cast concrete panels that are commonly provided at railway grade crossings between and alongside the rails rest on the pads. The pads may be extruded from a variety of natural or synthetic elastomeric materials. The pads include a panel or body formed of the elastomeric material with an exterior surface. A synthetic, polymeric coating is applied to at least selected portions of the exterior surface of the elastomeric body. The coating provides improved properties which allow more standard elastomers to be utilized for the main body of the component. The coatings can also be applied to railroad tie boots to provide increased ozone resistance.

1 . An elastomeric component used in a railway line emplacement, the elastomeric component comprising: 
 an elastomeric body having an exterior surface;    a synthetic, polymeric surface coating applied to at least selected portions of the exterior surface of the elastomeric body, the surface coating comprising a one-part, room temperature curing hydrogenated nitrile butadiene rubber base coating.    
   
   
       2 . The elastomeric component of  claim 1 , wherein the component is a railway tie pad.  
   
   
       3 . The elastomeric component of  claim 1 , wherein the component is a railway line boot or shoe.  
   
   
       4 . The elastomeric component of  claim 1 , wherein the surface coating is selected from the family of coatings sold commercially by the Lord Corporation as the HPC family of coatings.  
   
   
       5 . A tie pad of elastomeric material for use atop an elongate tie of a track having rails supported by a plurality of said ties, the tie pad comprising: (a) a main panel locatable on said tie and having a length, width, and a first side margin extending longitudinally along said main panel, the top surface of said main panel generally defining a plane; (b) a first flange, adjacent said first side margin of said main panel and engagable with said tie, said first flange having an inner margin connected to said first side margin of said main panel; and (c) a first shoulder projectable above said plane and located proximate said interconnection of said first side margin of said main panel and said inner margin of said first flange, said first shoulder extending longitudinally for at least a portion of said main panel; and 
 a synthetic, polymeric surface coating applied to at least selected portions of the exterior surface of the main panel, the surface coating comprising a one-part, room temperature curing hydrogenated nitrile butadiene rubber base coating.    
   
   
       6 . A railroad tie emplacement, comprising: 
 a rail supported atop a railroad tie;    a railroad tie boot formed of a resilient elastomer, the boot having an initially open interior, a bottom, surrounding sidewalls and an open top;    a railroad tie located within the railroad tie boot, the tie having an exposed upper surface which is peripherally surrounded by an upper exposed lip of the railroad tie boot;    a concrete substrate surrounding the bottom and sidewalls of the railroad tie boot; and    wherein a synthetic, polymeric surface coating is applied to at least the exposed tip portion of the railroad tie boot, the surface coating comprising a one-part, room temperature curing hydrogenated nitrile butadiene rubber base coating.    
   
   
       7 . The tie emplacement of  claim 6 , wherein the railroad tie is formed from a material selected from the group consisting of concrete and wood.  
   
   
       8 . The tie emplacement of  claim 6 , wherein the resilient elastomer which is coated with the surface coating is a styrene butadiene rubber.  
   
   
       9 . The tie emplacement of  claim 8 , wherein the surface coating is selected from the family of coatings sold commercially by the Lord Corporation as the HPC family of coatings.  
   
   
       10 . The tie emplacement of  claim 8 , wherein the surface coating has the following published specifications:  
     
       
         
               
               
               
             
                   
                   
               
                   
                   
               
                   
                 Appearance 
                 Clear Liquid with Orange Hue 
               
                   
                 Viscosity, cps @ 77° F. (25° C.) 
                  20-100 
               
                   
                 Density 
               
                   
                 Lb/gal 
                 6.72-6.92 
               
                   
                 (kg/m 3 ) 
                 (805.23-829.20) 
               
                   
                 Solids Content, % 
               
                   
                 by Weight 
                 10.6 
               
                   
                 by Volume 
                 7.7-8.8 
               
                   
                 Flash Point (Seta), ° F. (° C.) 
                 60 (15.6) 
               
                   
                 Solvents 
                 Methyl Ethyl Ketone (MEK)