Methods for treating rubber-containing particles and products produced therefrom

Abstract

A method and system for treating rubber-containing elastomers to produce materials suitable for blending with thermoplastic or thermoset polymers are disclosed. The elastomers may comprise virgin or recycled particulate rubber such as from used tires. The blended rubber and polymer materials possess thermoplastic properties and can be reused many times.

1 . A method of treating rubber-containing particles comprising:
 mixing rubber-containing particles, at least one fatty acid-containing material and linear low density polyethylene in a mixer to produce a rubber-containing particulate mixture.   
     
     
         2 . The method of  claim 1 , wherein the linear low density polyethylene forms a coating on the rubber-containing particles. 
     
     
         3 . The method of  claim 1 , wherein the rubber-containing particles and the fatty acid-containing material are initially mixed followed by addition of the linear low density polyethylene. 
     
     
         4 . The method of  claim 1 , wherein the rubber-containing particles are initially mixed prior to addition of the fatty acid-containing material, wherein the fatty-acid containing material is not pre-heated prior to mixing with the rubber-containing particles. 
     
     
         5 . The method of  claim 4 , wherein the mixer comprises a friction mixer and the mixing of the rubber-containing particles generates sufficient heat to raise the temperature of the rubber-containing particulate mixture to a selected mixing temperature. 
     
     
         6 . The method of  claim 5 , wherein the temperature is at least 200° F. 
     
     
         7 . The method of  claim 1 , wherein the rubber-containing particles comprise recycled rubber. 
     
     
         8 . The method of  claim 1 , wherein the fatty acid-containing material comprises soya oil or a derivative thereof, or peanut oil or a derivative thereof. 
     
     
         9 . The method of  claim 1 , wherein the rubber-containing particles and the fatty acid-containing material are mixed in a weight ratio of from about 90 to about 99 weight percent rubber particles and from about 1 to about 10 weight percent fatty acid-containing material. 
     
     
         10 . The method of  claim 1 , wherein the rubber-containing particulate mixture produced by the mixing step have a volume at least 5 percent greater than a volume of the rubber-containing particles added to the mixer. 
     
     
         11 . The method of  claim 1 , wherein the linear low density polyethylene is present in an amount of from about 2 to about 10 weight percent of the mixture. 
     
     
         12 . The method of  claim 1 , wherein the linear low density polyethylene is present in an amount of from about 1 to about 5 weight percent of the mixture. 
     
     
         13 . The method of  claim 1 , further comprising adding at least one additive to the rubber-containing particulate mixture and further mixing the rubber-containing particulate mixture, the additive selected from Wollastonite, talc, ethylene propylene diene monomer, polyphenylene sulfone-based polymer, maleic anhydride, calcium carbonate, cross-linker and dispersing agent. 
     
     
         14 . The method of  claim 13 , wherein the additive is added with the linear low density polyethylene. 
     
     
         15 . The method of  claim 13 , wherein the additive comprises talc in an amount of from about 1 to about 20 weight percent of the mixture. 
     
     
         16 . The method of  claim 1 , further comprising treating the rubber-containing particulate mixture with a source of ultraviolet radiation. 
     
     
         17 . Rubber-containing particles comprising rubber particles coated with linear low density polyethylene, wherein the rubber particles have a maximum particle size of 10 mesh. 
     
     
         18 . The rubber-containing particles of  claim 17 , wherein the linear low density polyethylene comprises from 2 to 10 weight percent of the rubber-containing particles. 
     
     
         19 . The rubber-containing particles of  claim 17 , wherein the rubber particles are treated with a fatty-acid containing material. 
     
     
         20 . The rubber-containing particles of  claim 19 , wherein the rubber particles treated with the fatty-acid containing material have a volume at least 5 percent greater than a volume of untreated rubber particles.