Butyl rubber compounds comprising a three component mixed modifier system
View Patent ↗Rubber compounds containing a halobutyl elastomer, at least one additional elastomer, a mineral filler and at least a three component mixed modifier system comprising a silane compound, a phosphine compound and an additive containing at least one hydroxyl group and a functional group containing a basic amine. A process for preparing the compounds is also disclosed. The compounds are particularly useful in tire treads and exhibit improved processability, traction, rolling resistance and wear properties.
1. A rubber compound comprising a halobutyl elastomer, at least one additional elastomer, a mineral filler, and an at least three component mixed modifier system comprising a silane, a phosphine, and an additive comprising at least one hydroxyl group and a functional group comprising a basic amine.
2. The rubber compound according to claim 1 , wherein the halobutyl elastomer comprises a halogenated copolymer of at least an isoolefin and a conjugated diolefin.
3. The rubber compound according to claim 2 , wherein the isoolefin comprises isobutylene and wherein the conjugated diolefin comprises isoprene.
4. The rubber compound according to claim 1 , wherein the halobutyl elastomer comprises a halogenated terpolymer of an isoolefin, a conjugated diolefin, and a vinyl aromatic monomer.
5. The rubber compound according to claim 4 , wherein the isoolefin comprises isobutylene, the conjugated diene comprises isoprene and the vinyl aromatic monomer comprises p-methylstyrene.
6. The rubber compound according to claim 1 , wherein the additional elastomer comprises BR, SBR, NBR, NR, ENR or mixtures thereof.
7. The rubber compound according to claim 1 , wherein the mineral filler comprises silica.
8. The rubber compound according to claim 1 , wherein the silane comprises an aminosilane or a sulphur-containing silane.
9. The rubber compound according to claim 8 , wherein the silane comprises bis[3-(triethoxysilyl)propyl]-monosulfane, bis[3(triethoxysilyl)propyl]disulfane, bis[3-(triethoxysilyl)propyl]trisulfane, bis[3(triethoxysilyl)propyl]tetrasulfane, bis[2-(triethoxysilyl)ethyl]-tetrasulfane, 3-(triethoxysilyl)propanthiol, or a mixture thereof.
10. The rubber compound according to claim 1 , wherein the phosphine comprises trimethylphosphine, triethylphosphine, triisopropylphosphine, tri-n-butylphosphine, triphenylphosphine, or a mixture thereof.
11. The rubber compound according to claim 1 , wherein the additive comprising at least one hydroxyl group and a functional group containing a basic amine comprises an aminoalcohol.
12. The rubber compound according to claim 11 , wherein the aminoalcohol comprises mono ethanol amine (MEA), N,N-dimethylaminoethanol (DMAE), diethanolamine (DEA), dibutyl-aminoethanol (DBAE), methyldiethanolamine (MDEA), phenyldiethanolamine (PDEA), or a mixture thereof.
13. The rubber compound according to claim 1 , wherein the phosphine is present in the range of 0.1 to 6.0 phr.
14. The rubber compound according to claim 1 , wherein the additive comprising at least one hydroxyl group and a functional group containing a basic amine is present in the range of 0.1 to 6.0 phr.
15. The rubber compound according to claim 1 , wherein the silane is present in the range of 0.1 to 15.0 phr.
16. The rubber compound according to claim 1 , wherein the phosphine comprises triphenylphosphine and is present in the range of 0.1 to 6.0 phr, wherein the additive comprising at least one hydroxyl group and a functional group containing a basic amine comprises N,N-dimethylaminoethanol and is present in the range of 0.1 to 6.0 phr and wherein the silane comprises bis[3(triethoxysilyl)propyl]tetrasulfane and is present in the range of 0.1 to 15.0 phr.
17. The rubber compound according to claim 1 , wherein the tan delta at 0° C. is greater than 0.325, wherein the tan delta at 60° C. is less than 0.120, wherein the abrasion volume loss (DIN) is less than 165 mm 3 , and wherein the tensile at break values are greater than 13.0 MPa.
18. A process for preparing a rubber compound comprising admixing a halobutyl elastomer, at least one additional elastomer, a mineral filler and an at least three component mixed modifier system comprising a silane, a phosphine and an additive comprising at least one hydroxyl group and a functional group comprising a basic amine.
19. The process according to claim 18 , wherein the three components of the mixed modifier system, or portions thereof, are pre-mixed.
20. The process according to claim 18 , wherein the three components of the mixed modifier system are admixed with a pre-mixed combination of the halobutyl elastomer, the at least one additional elastomer and the mineral filler.