Modified polymer compositions
A process for the continuous preparation of modified elastomeric polymers includes (i) providing and polymerizing at least one conjugated diene monomer and, optionally, one or more aromatic vinyl monomer in the presence of an anionic initiator and a compound according to Formula 1, e.g. 2,2-di-(2-oxolanyl)propane or a derivative thereof, to provide a living anionic polymer; and (ii) adding a “sulfanylsilane” compound to the living anionic polymer. Elastomeric polymers obtainable according to the above process and compositions including the elastomeric polymer and, optionally, further constituents such as oil, filler and/or vulcanizing agent are described. A process for the preparation of a cross-linked elastomeric polymer that includes adding a vulcanizing agent to the elastomeric polymer, as well as articles and compositions that include the elastomeric polymer, the cross-linked elastomeric polymer or both are described.
1. A process for the continuous preparation of an elastomeric polymer, said process comprising the steps of:
(i) providing and polymerizing at least one conjugated diene monomer and, optionally, one or more aromatic vinyl monomer at a temperature of 110° C. or less in an organic solvent in the presence of an active initiator and a compound according to Formula 1:
wherein O in Formula 1 is oxygen, R1 and R2 in Formula 1 are each independently hydrogen or an alkyl group; R3, R4, R5, R6, R7 and R8 are each independently selected from hydrogen or an alkyl group; n is an integer value selected from 1, 2, 3 or 4; and wherein the active initiator is an anionic initiator and the molar ratio of the compound according to Formula 1 to active initiator is from 0.15 to 10; to provide a living anionic polymer; and
(ii) adding a first quantity of a compound according to Formula 2 to the living anionic polymer in an amount such that the molar ratio of the compound according to Formula 2 to active initiator is of from 0.21 or more:
(RO) 3 Si-A-S—SiR′R″R′″ (Formula 2)
wherein S in Formula 2 is sulphur, Si is silicon, O is oxygen; groups R are each independently selected from alkyl, aralkyl or aryl; groups R′, R″ and R′″ are independently from each other selected from alkyl, aralkyl or aryl; A is a divalent hydrocarbyl group.
2. The process according to claim 1 , wherein step (ii) of adding the compound of Formula 2 to the living anionic polymer is started at a monomer conversion of between 85 and 100 percent by weight based on the amount of monomers provided.
3. The process according to claim 1 , wherein the process comprises the additional step (iii) of:
(iii) subsequently adding a second quantity of the compound according to Formula 2 and/or adding a compound according to Formula 3 in an amount such that the molar ratio of the compound according to Formula 2 and/or Formula 3 as added in step (iii) to active initiator is of from 0.21 or more:
(RO) 2 R″″Si-A-S—SiR′R″R′″ (Formula 3)
wherein groups R in Formula 3 are independently selected from alkyl, aralkyl or aryl groups; groups R′, R″ and R′″ are independently selected from alkyl, aralkyl or aryl; group R″″ is selected from an alkyl, aralkyl or aryl; A is a divalent hydrocarbyl group.
4. The process according to claim 1 , wherein the at least one conjugated diene monomer is selected from 1,3-butadiene, 2-alkyl-1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2,4-hexadiene, 1,3-hexadiene, 1,3-heptadiene, 1,3-octadiene, 2-methyl-2,4-pentadiene, cyclopentadiene, 2,4-hexadiene and/or 1,3-cyclooctadiene.
5. The process according to claim 1 , wherein the organic solvent is selected from one or more of butene, butane, pentane, cyclohexane, hexane, heptane, octane, benzene and toluene.
6. The process according to claim 1 , wherein the anionic initiator comprises an organo metal compound having at least one lithium atom and comprising a non-polar C1-C20 hydrocarbon group or a mixture thereof.
7. The process according to claim 1 , wherein the compound according to Formula 1 is di(tetrahydrofuryl)propane.
8. An elastomeric polymer obtainable according to claim 1 .
9. A composition comprising the elastomeric polymer according to claim 8 .
10. The composition according to claim 9 , further comprising oil and/or a filler.
11. The composition according to claim 9 , further comprising a vulcanizing agent.
12. The composition according to claim 9 , wherein the filler is selected from one or more of silica and carbon black.
13. An article comprising the composition according to any of claim 9 .
14. The article according to claim 13 , wherein the article is a tire tread, a tire side wall, a conveyer belt, a seal or a hose.
15. A process for the preparation of a crosslinked elastomeric polymer, comprising step (iv) of:
(iv) adding a vulcanizing agent to the elastomeric polymer according to claim 8 and cross-linking the elastomeric polymer.
16. A crosslinked elastomeric polymer obtainable according claim 15 .
17. A composition comprising the crosslinked elastomeric polymer according to claim 16 .