Chemically functionalized renewed rubber composition
The renewed rubber of this invention can be used in rubber formulations that are used in manufacturing a wide array of rubber products, including tires, power transmission belts, conveyor belts, hoses, and a wide array of other products. The present invention more specifically discloses a method for manufacturing an environmentally friendly, chemically functionalized, renewed rubber composition having a highly desirable combination of physical properties and which exhibits excellent processability comprising the steps of (1) blending a micronized rubber powder with a processing aid and a chemical functionalizing agent to produce a blended mixture; (2) processing the blended mixture under conditions of high shear and low temperature to produce a reacted mixture; (3) adding a stabilizer to the reacted mixture to produce the chemically functionalized renewed rubber composition.
1. A functionalized renewed rubber composition which is comprised of an elastomeric polymer and a stabilizer; wherein the functionalized renewed rubber composition has a crosslink density which is within the range of 0.05×10 −5 mole/g to 2.0×10 −5 mole/g, and wherein the functionalized renewed rubber composition has a soluble fraction of less than 90 percent.
2. The functionalized renewed rubber composition as specified in claim 1 which is based on a tire rubber infeed.
3. The rubber composition as specified in claim 1 wherein the elastomeric polymer is a diene rubber, wherein the stabilizer is a vulcanization retarder and wherein the elastomeric polymer has a soluble fraction of less than 30 percent.
4. The rubber composition as specified in claim 1 wherein the elastomeric polymer is recycled tire rubber.
5. The rubber composition as specified in claim 1 wherein the stabilizer is N-cyclohexyl(thio)phthalimide.
6. The functionalized renewed rubber composition as specified in claim 3 which is futher comprised of a soluble rubber fraction, wherein the soluble rubber is functionalized.
7. The functionalized renewed rubber composition as specified in claim 1 wherein the functionalized renewed rubber composition is in the form of a sheet, a slab, a hexahedron, or a pellet.
8. The functionalized renewed rubber composition as specified in claim 1 wherein the rubber composition has a crosslink density which is within the range of 0.1 to 1.8×10 −5 mole/g.
9. The functionalized renewed rubber composition as specified in claim 1 wherein the functionalized renewed rubber composition is chemically functionalized, and wherein the functional groups are covalently bonded to the polymer chains of the rubber through one or more sulfur atoms.
10. The functionalized renewed rubber composition as specified in claim 1 wherein the renewed rubber composition is derived from tire sidewalls, tire innerliners, or tire treads.
11. The functionalized renewed rubber composition as specified in claim 9 , wherein the renewed rubber composition is predominantly styrene-butadiene rubber.
12. The functionalized renewed rubber composition as specified in claim 9 wherein the renewed rubber composition is derived from tire treads which are comprised of a blend of high cis-1,4-polybutadiene rubber and one or more additional rubbers wherein the high cis-1,4-polybutadiene rubber has a cis-microstructure content of at least 95 percent.
13. The functionalized renewed rubber composition as specified in claim 3 , wherein the renewed rubber composition is derived from tire sidewalls, tire innerliners, or tire treads.
14. The functionalized renewed rubber composition as specified in claim 1 , wherein the stabilizer is present at a level within the range of about 0.25 phr to about 5 phr.
15. A rubber formulation which is comprised of a blend of 5 phr to 50 phr of the functionalized renewed rubber composition as specified in claim 1 and from 50 phr to 95 phr of virgin natural rubber.
16. The functionalized renewed rubber composition as specified in claim 1 , wherein the elastomeric polymer has a soluble fraction of less than 50%.
17. The functionalized renewed rubber composition as specified in claim 1 , wherein said functionalized renewed rubber composition is further comprised of natural rubber.
18. The functionalized renewed rubber composition as specified in claim 1 , wherein said composition is further comprised of 1 phr to 99 phr of a rubber selected from the group consisting of virgin natural rubber, emulsion styrene butadiene rubber, solution styrene butadiene rubber and high cis,1,4-polybutadiene rubber.
19. The functionalized renewed rubber composition as specified in claim 1 , wherein said composition is further comprised of a reinforcing filler selected from the group consisting of carbon black and silica.
20. The functionalized renewed rubber composition as specified in claim 1 , wherein the elastomeric polymer has a solubility fraction of less than 30%.
21. The functionalized renewed rubber composition as specified in claim 1 , wherein the elastomeric polymer contains about 56% polysulphidic crosslinks and about 35% monosulphidic crosslinks.