Improved Coatings for Pelletized Thermoplastic Pavement Marking Compositions

Abstract

A coating for pelletized thermoplastic road marking material is provided in which at least one of waxes, silica compounds, and inorganic compounds is provided on the surface of the thermoplastic pellet. The pellet is formed by mixing a binder mixture with a filler mixture, heating the mixed ingredients while mixing into a homogenous molten mixture and then extruding the molten mixture. The extruded material is cooled, cut into individual pellets and then coated. The coating prevents clumping of the pellets and also imparts improved flowability and lower melting point properties. Preferred coatings include micronized polyethylene wax, silicates, silanes, silicones, siliconates, fluoropolymers, calcium carbonate and zeolite.

1 - 18 . (canceled) 
     
     
         19 . A coating for pelletized thermoplastic road marking material comprising a binder and a filler including retroreflective elements, said coating comprising at least one of waxes, silica compounds, and inorganic compounds. 
     
     
         20 . The coating of  claim 19 , wherein said coating is a micronized polyethylene wax. 
     
     
         21 . The coating of  claim 19 , wherein said coating is one of a silicate, functionalized silane, silicone, and siliconate. 
     
     
         22 . The coating of  claim 21 , wherein the coating is one of a group of amino or alkyl silanes, alkyl silicones and sodium methylsiliconate. 
     
     
         23 . The coating of  claim 19 , wherein said coating is a fluoropolymer. 
     
     
         24 . The coating of  claim 23 , wherein said fluoropolymer is a cationic fluoropolymer. 
     
     
         25 . The coating of  claim 23 , wherein said fluoropolymer is an anionic fluoropolymer. 
     
     
         26 . The coating of  claim 19 , wherein said coating is one of a calcium carbonate and a zeolite. 
     
     
         27 . The coating of  claim 19 , wherein the silica compound is one of a nano silica solution, silica emulsion, and sodium silicate. 
     
     
         28 . A composition for coating a pelletized road marking composition formed from a binder mixture comprising one or more member selected from the group consisting of rosin resins, waxes, and plasticizers, and a filler mixture comprising reflective elements, said coating comprising one of waxes, silica compounds, and inorganic compounds. 
     
     
         29 . The composition of  claim 28 , wherein said coating is a micronized polyethylene wax. 
     
     
         30 . The composition of  claim 28 , wherein said coating is one of a silicate, functionalized silane, silicone, and siliconate. 
     
     
         31 . The composition of  claim 30 , wherein the coating is one of a group of amino or alkyl silanes, alkyl silicones and sodium methylsiliconate. 
     
     
         32 . The composition of  claim 28 , wherein said coating is a fluoropolymer. 
     
     
         33 . The composition of  claim 32 , wherein said fluoropolymer is a cationic fluoropolymer. 
     
     
         34 . The composition of  claim 32 , wherein said fluoropolymer is a anionic fluoropolymer. 
     
     
         35 . The composition of  claim 28 , wherein said coating is one of a calcium carbonate and a zeolite. 
     
     
         36 . The composition of  claim 28 , wherein the silica compound is one of a nano silica solution, silica emulsion, and sodium silicate.