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US 7,767,722 B2Granted
Devulcanized rubber and methods
AssigneeGreen Source Energy LLC
InventorsLiang-tseng Fan, Mohammad Reza Shafie
Life of this patent
Estimating the term…
Abstract
Vulcanized rubber is devulcanized by contacting the vulcanized rubber with a terpentine liquid in a reaction mixture in the absence of an alkali metal.
Claims64
A method of devulcanizing rubber comprising:
- providing a vulcanized rubber having a sulfur content with sulfur cross-links;
- and,
- contacting said vulcanized rubber with a devulcanizing agent in a reaction mixture, the devulcanizing agent being a turpentine liquid, wherein said turpentine liquid is present in an amount sufficient such that said turpentine liquid acts to substantially to break said cross-links and to substantially reduce said sulfur content of said vulcanized rubber and wherein the action of said turpentine liquid results in substantial devulcanization of said vulcanized rubber, wherein during said contacting, the sulfur cross-links broken by said devulcanizing agent is in an amount of from about 75 to 100% of sulfur cross-links originally contained within said vulcanized rubber.
A method of devulcanizing rubber comprising:
- providing a vulcanized rubber having sulfur cross-links;
- and
- contacting said vulcanized rubber with a devulcanizing agent in a reaction mixture, the devulcanizing agent being a turpentine liquid, wherein said turpentine liquid is present in an amount sufficient such that action of said turpentine liquid results in breaking of said cross-links and said action results in substantial devulcanization of said vulcanized rubber, wherein during said contacting, the sulfur cross-links broken by said devulcanizing agent is in an amount of from about 75 to 100% of sulfur cross-links originally contained within said vulcanized rubber.
A method of devulcanizing rubber comprising:
- providing a vulcanized rubber having a sulfur content with sulfur cross-links;
- and
- contacting said vulcanized rubber with a devulcanizing agent in a reaction mixture, the devulcanizing agent being a turpentine liquid, wherein said turpentine liquid is present in an amount sufficient such that said turpentine liquid acts to substantially to break said cross-links and to substantially reduce said sulfur content of said vulcanized rubber and wherein the action of said turpentine liquid results in substantial devulcanization of said vulcanized rubber, wherein during said contacting, the sulfur cross-links broken by said devulcanizinq agent is in an amount of at least about 54% of sulfur cross-links originally contained within said vulcanized rubber.
A method of devulcanizing rubber comprising:
- providing a vulcanized rubber having a sulfur content with sulfur cross-links;
- and
- contacting said vulcanized rubber with a turpentine liquid devulanizing agent in a reaction mixture, wherein said turpentine liquid is present in an amount sufficient such that said turpentine liquid acts to substantially to break said cross-links and to substantially reduce said sulfur content of said vulcanized rubber and wherein the action of said turpentine liquid results in substantial devulcanization of said vulcanized rubber, wherein said turpentine liquid has a weight greater than said vulcanized rubber in said reaction mixture, wherein during said contacting, the sulfur cross-links broken by said devulcanizing agent is in an amount of from about 75 to 100% of sulfur cross-links originally contained within said vulcanized rubber.
A method of devulcanizing rubber comprising:
- providing a vulcanized rubber having a sulfur content with sulfur cross-links;
- and
- contacting said vulcanized rubber in a reaction mixture containing a turpentine liquid devulcanizing agent, wherein said turpentine liquid is present in an amount sufficient such that action of said turpentine liquid results in breaking of said cross-links and said action results in substantial devulcanization of said vulcanized rubber, wherein said turpentine liquid has a weight greater than said vulcanized rubber in said reaction mixture, wherein said contacting substantially reduces said sulfur content of said rubber and wherein said devulcanization of said rubber is at least about 75%.
A method of devulcanizing rubber comprising:
- providing a vulcanized rubber having a sulfur content with sulfur cross-links;
- and,
- contacting said vulcanized rubber with a turpentine liquid as a devulcanizing agent in a reaction mixture, wherein said turpentine liquid is present in an amount sufficient such that said turpentine liquid acts to substantially to break said cross-links and to substantially reduce said sulfur content of said vulcanized rubber, and wherein the action of said turpentine liquid results in substantial devulcanization of said vulcanized rubber, wherein substantially all of the breaking of said cross-links, substantially all of the reduction of said sulfur content and substantially all of said devulcanization results from activity of said turpentine liquid, wherein during said contacting, the sulfur cross-links broken by said devulcanizing agent is an amount that corresponds to an amount of from about 75 to 100% of sulfur cross-links originally contained within said vulcanized rubber.
A method of devulcanizing rubber comprising:
- providing a vulcanized rubber having sulfur cross-links;
- and
- contacting said vulcanized rubber in a reaction mixture containing a turpentine liquid as a devulcanizing agent, wherein said turpentine liquid is present in an amount sufficient such that action of said turpentine liquid results in breaking of said cross-links and said action results in substantial devulcanization of said vulcanized rubber, wherein substantially all of the breaking of said cross-links and substantially all of said devulcanization results from activity of said turpentine liquid, wherein said contacting substantially reduces said sulfur content of said rubber and wherein said devulcanization of said rubber is at least about 75%.
Dependencies are inferred from the claim text.