Rubber composition for a tire comprising a reinforcing inorganic filler and an (inorganic filler/elastomer) coupling system
The present invention is directed to a rubber composition that is useful for the manufacture of tires, where the composition is based on a diene elastomer, a reinforcing inorganic filler, and a coupling system. The coupling system comprises a polysulfurized alkoxysilane (“PSAS”) coupling agent (inorganic filler/diene elastomer) associated with an aldimine having the general formula R—CH═N—R and a guanidine derivative. The present invention is further directed to tires and semi-finished products for tires comprising a rubber composition according to the invention. The invention is also directed to a coupling system (inorganic filler/diene elastomer) for a rubber composition based on a diene elastomer reinforced by an inorganic filler, where the coupling system comprises a polysulfurized alkoxysilane (PSAS) coupling agent in association with an aldimine having the general formula R—CH═N—R and a guanidine derivative.
1. A rubber composition useful for the manufacture of tires, based on a diene elastomer, a reinforcing inorganic filler, and a coupling system, said coupling system comprising a polysulfurized alkoxysilane coupling agent (inorganic filler/diene elastomer) associated with an aldimine having the general formula R—CH═N—R and a guanidine derivative.
2. The composition of claim 1 , wherein the diene elastomer is selected from the group consisting of polybutadienes, polyisoprenes, natural rubber, butadiene copolymers, isoprene copolymers, and mixtures thereof.
3. The composition of claim 1 , wherein the reinforcing inorganic filler is a siliceous filler or an aluminous filler.
4. The composition of claim 1 , wherein the polysulfurized alkoxysilane is a bis-(C 1 -C 4 )alkoxysilyl(C 1 -C 10 )alkyl polysulfide.
5. The composition of claim 1 , wherein at least one of the radicals R of the aldimine is an aryl group.
6. The composition of claim 1 , wherein the aldimine is selected from the group consisting of aldimines derived from aniline and aldimines derived from cyclohexylamine.
7. The composition of claim 1 , in which the quantity of aldimine represents between 1% and 20% relative to the weight of polysulfurized alkoxysilane.
8. The composition of claim 1 , in which the total quantity of the polysulfurized alkoxysilane and the aldimine represents less than 10% relative to the weight of the reinforcing inorganic filler.
9. The composition of claim 1 , wherein the guanidine derivative is N,N′-diphenylguanidine.
10. The composition of claim 1 , in which the quantity of the guanidine derivative represents between 0.5 and 4% relative to the weight of the reinforcing inorganic filler.
11. The composition of claim 1 , in which the total quantity of the coupling system comprising the polysulfurized alkoxysilane, the aldimine and the guanidine derivative represents between 2% and 20% relative to the weight of the reinforcing inorganic filler.
12. The composition of claim 2 , wherein the diene elastomer is a butadiene-styrene copolymer (SBR) having a styrene content of between 20% and 30% by weight, a content of vinyl bonds of the butadiene part of between 15% and 65% by weight, a content of trans-1,4 bonds of between 20% and 75%, and a glass transition temperature of between −20° C. and −55° C.
13. The composition of claim 2 , wherein the diene elastomer is a mixture of a butadiene-styrene copolymer (SBR) having a styrene content of between 20% and 30% by weight, a content of vinyl bonds of the butadiene part of between 15% and 65% by weight, a content of trans-1,4 bonds of between 20% and 75%, and a glass transition temperature of between −20° C. and −55° C.; and a polybutadiene having more than 90% cis-1,4 bonds.
14. The composition of claim 1 further comprising carbon black.
15. The composition of claim 4 , wherein the polysulfurized alkoxysilane is a bis-(C 1 -C 4 )alkoxy silylpropyl polysulfide.
16. The composition of claim 15 , wherein the polysulfurized alkoxysilane is bis-3-triethoxysilylpropyl disulfide or bis-3-triethoxysilylpropyl tetrasulfide.
17. The composition of claim 6 , wherein the aldimine is selected from the group consisting of compounds having the formulae (III-1) to (III-5):
18. The rubber composition of claim 1 , wherein the composition is in the vulcanized state.
19. A process for preparing a sulfur-vulcanizable rubber composition useful for the manufacture of tires comprising: incorporating by kneading into a diene elastomer, a reinforcing inorganic filler, and a coupling system, said coupling system comprising a polysulfurized alkoxysilane coupling agent (inorganic filler/diene elastomer) associated with an aldimine having the general formula R—CH═N—R and a guanidine derivative; and kneading the entire mixture thermomechanically, in one or more stages, until a maximum temperature of between 120° C. and 190° C. is reached.
20. The process of claim 19 , wherein the diene elastomer is selected from the group consisting of polybutadienes, polyisoprenes, natural rubber, butadiene copolymers, isoprene copolymers, and mixtures thereof.
21. The process of claim 19 , wherein the reinforcing inorganic filler is a siliceous filler or an aluminous filler.
22. The process of claim 19 , wherein the polysulfurized alkoxysilane is a bis-(C 1 -C 4 )alkoxysilyl(C 1 -C 10 )alkyl polysulfide.
23. The process of claim 19 , wherein at least one of the radicals R of the aldimine is an aryl group.
24. The process of claim 19 , wherein the aldimine is selected from the group consisting of aldimines derived from aniline and aldimines derived from cyclohexylamine.
25. The process of claim 19 , in which the quantity of aldimine represents between 1% and 20% relative to the weight of polysulfurized alkoxysilane.
26. The process of claim 19 , wherein the total quantity of the polysulfurized alkoxysilane and the aldimine represents less than 10% relative to the weight of the reinforcing inorganic filler.
27. The process of claim 19 , wherein the guanidine derivative is N,N′-diphenylguanidine.
28. The process of claim 19 , in which the quantity of the guanidine derivative represents between 0.5 and 4% relative to the weight of the reinforcing inorganic filler.
29. The process of claim 19 , in which the total quantity of the coupling system comprising the polysulfurized alkoxysilane, the aldimine and the guanidine derivative represents between 2% and 20% relative to the weight of the reinforcing inorganic filler.
30. The process of claim 22 , wherein the polysulfurized alkoxysilane is a bis-(C 1 -C 4 )alkoxysilylpropyl polysulfide.
31. The process of claim 24 , wherein the aldimine is selected from the group consisting of compounds having the formulae (III-1) to (III-5):
32. The process of claim 19 , wherein the maximum kneading temperature is between 130° C. and 180° C.
33. A tire comprising a rubber composition, wherein the rubber composition is based on a diene elastomer, a reinforcing inorganic filler, and a coupling system, said coupling system comprising a polysulfurized alkoxysilane coupling agent (inorganic filler/diene elastomer) associated with an aldimine having the general formula R—CH═N—R and a guanidine derivative.
34. The tire of claim 33 , wherein the diene elastomer is selected from the group consisting of polybutadienes, polyisoprenes, natural rubber, butadiene copolymers, isoprene copolymers, and mixtures thereof.
35. The tire of claim 33 , wherein the reinforcing inorganic filler is a siliceous filler or an aluminous filler.
36. The tire of claim 33 , wherein the polysulfurized alkoxysilane is a bis-(C 1 -C 4 )alkoxysilyl (C 1 -C 10 )alkyl polysulfide.
37. The tire of claim 33 , wherein at least one of the radicals R of the aldimine is an aryl group.
38. The tire of claim 33 , wherein the aldimine is selected from the group consisting of aldimines derived from aniline and aldimines derived from cyclohexylamine.
39. The tire of claim 33 , in which the quantity of aldimine represents between 1% and 20% relative to the weight of polysulfurized alkoxysilane.
40. The tire of claim 33 , in which the total quantity of the polysulfurized alkoxysilane and the aldimine represents less than 10% relative to the weight of the reinforcing inorganic filler.
41. The tire of claim 33 , wherein the guanidine derivative is N,N′-diphenylguanidine.
42. The tire of claim 33 , in which the quantity of the guanidine derivative represents between 0.5 and 4% relative to the weight of the reinforcing inorganic filler.
43. The tire of claim 33 , in which the total quantity of the coupling system comprising the polysulfurized alkoxysilane, the aldimine and the guanidine derivative represents between 2% and 20% relative to the weight of the reinforcing inorganic filler.
44. The tire of claim 33 , wherein the diene elastomer is a butadiene-styrene copolymer (SBR) having a styrene content of between 20% and 30% by weight, a content of vinyl bonds of the butadiene part of between 15% and 65% by weight, a content of trans-1,4 bonds of between 20% and 75%, and a glass transition temperature of between −20° C. and −55° C.
45. The tire of claim 36 , wherein the polysulfurized alkoxysilane is a bis-(C 1 -C 4 )alkoxy silylpropyl polysulfide.
46. The tire of claim 45 , wherein the polysulfurized alkoxysilane is bis-3-triethoxysilylpropyl disulfide or bis-3-triethoxysilylpropyl tetrasulfide.
47. The tire of claim 38 , wherein the aldimine is selected from the group consisting of compounds having the formulae (III-1) to (III-5):
48. A tire tread comprising a rubber composition, wherein the rubber composition is based on a diene elastomer, a reinforcing inorganic filler, and a coupling system, said coupling system comprising a polysulfurized alkoxysilane coupling agent (inorganic filler/diene elastomer) associated with an aldimine having the general formula R—CH═N—R and a guanidine derivative.
49. The tread of claim 48 , wherein the diene elastomer is selected from the group consisting of polybutadienes, polyisoprenes, natural rubber, butadiene copolymers, isoprene copolymers, and mixtures thereof.
50. The tread of claim 48 , wherein the reinforcing inorganic filler is a siliceous filler or an aluminous filler.
51. The tread of claim 48 , wherein the polysulfurized alkoxysilane is a bis-(C 1 -C 4 )alkoxysilyl(C 1 -C 10 )alkyl polysulfide.
52. The tread of claim 48 , wherein at least one of the radicals R of the aldimine is an aryl group.
53. The tread of claim 48 , wherein the aldimine is selected from the group consisting of aldimines derived from aniline and aldimines derived from cyclohexylamine.
54. The tread of claim 48 , in which the quantity of aldimine represents between 1% and 20% relative to the weight of polysulfurized alkoxysilane.
55. The tread of claim 48 , in which the total quantity of the polysulfurized alkoxysilane and the aldimine represents less than 10% relative to the weight of the reinforcing inorganic filler.
56. The tread of claim 48 , wherein the guanidine derivative is N,N′-diphenylguanidine.
57. The tread of claim 48 , in which the quantity of the guanidine derivative represents between 0.5 and 4% relative to the weight of the reinforcing inorganic filler.
58. The tread of claim 48 , in which the total quantity of the coupling system comprising the polysulfurized alkoxysilane, the aldimine and the guanidine derivative represents between 2% and 20% relative to the weight of the reinforcing inorganic filler.
59. The tread of claim 49 , wherein the diene elastomer is a butadiene-styrene copolymer (SBR) having a styrene content of between 20% and 30% by weight, a content of vinyl bonds of the butadiene part of between 15% and 65% by weight, a content of trans-1,4 bonds of between 20% and 75%, and a glass transition temperature of between −20° C. and −55° C.
60. The tread of claim 49 , wherein the diene elastomer is a mixture of a butadiene-styrene copolymer (SBR) having a styrene content of between 20% and 30% by weight, a content of vinyl bonds of the butadiene part of between 15% and 65% by weight, a content of trans-1,4 bonds of between 20% and 75%, and a glass transition temperature of between −20° C. and −55° C.; and a polybutadiene having more than 90% cis-1,4 bonds.
61. The tread of claim 51 , wherein the polysulfurized alkoxysilane is a bis-(C 1 -C 4 )alkoxy silylpropyl polysulfide.
62. The tread of claim 61 , wherein the polysulfurized alkoxysilane is bis-3-triethoxysilylpropyl disulfide or bis-3-triethoxysilylpropyl tetrasulfide.
63. The tread of claim 53 , wherein the aldimine is selected from the group consisting of compounds having the formulae (III-1) to (III-5):
64. A coupling system (inorganic filler/diene elastomer) for a rubber composition based on a diene elastomer reinforced by a inorganic filler, useful for the manufacture of tires, the coupling system comprising a polysulfurized alkoxysilane coupling agent in association with an aldimine having the general formula R—CH═N—R and a guanadine derivative.
65. The coupling system of claim 64 , wherein the polysulfurized alkoxysilane is a bis-(C 1 -C 4 )alkoxysilyl(C 1 -C 10 )alkyl polysulfide.
66. The coupling system of claim 64 , wherein at least one of the radicals R of the aldimine is an aryl group.
67. The coupling system of claim 64 , wherein the aldimine is selected from the group consisting of aldimines derived from aniline and aldimines derived from cyclohexylamine.
68. The coupling system of claim 67 , wherein the aldimine is selected from the group consisting of compounds having the formulae (III-1) to (III-5):
69. The coupling system of claim 64 , wherein the guanidine derivative is N,N′-diphenylguanidine.
70. A semi-finished product for a tire, comprising a rubber composition, wherein the rubber composition is based on a diene elastomer, a reinforcing inorganic filler, and a coupling system, said coupling system comprising a polysulfurized alkoxysilane coupling agent (inorganic filler/diene elastomer) associated with an aldimine having the general formula R—CH═N—R and a guanidine derivative.