Method of making diarlysilanediol containing polymers, polymer compositions and articles containing such polymers
A method of making a polymer with stable Mooney viscosity and molecular weight is described. A conjugated diolefin is reacted in a hydrocarbon solvent in the presence of an initiator to form a polymer. After forming the polymer, alkoxy silane terminal functionalizing groups are bonded to the polymer. A mixture of at least one of a first stabilizing agent having the formula (R) 4-n Si(OH) n wherein R is a C 1 to C 18 alkyl, C 1 to C 18 alkyl group containing a heteroatom such as nitrogen or oxygen, C 4 to C 8 cycloalkyl, or C 6 to C 18 aromatic group, and a at least one of a second stabilizing agents having the formula (R) 2 Si(OH) 2 wherein R is an aryl group, is then added to the polymer, optionally in the presence of hydrocarbon oil. The polymer is then desolvatized, resulting in a polymer with stable Mooney viscosity and molecular weight, even over prolonged periods of time. Compositions and articles containing the polymer are also described.
1. A method of making a polymer comprising,
reacting a conjugated diolefin in a hydrocarbon solvent in the presence of an initiator to form a polymer,
bonding alkoxy silane terminal functionalizing groups to the polymer,
adding a mixture of stabilizing agents to the polymer, including at least one of a first stabilizing agents having the formula (R) 4-n Si(OH) n wherein R is a C 1 to C 18 alkyl, C 1 to C 18 alkyl group containing a heteroatom such as nitrogen or oxygen, C 4 to C 8 cycloalkyl, or C 6 to C 18 aromatic group, and n is equal to 1,
and at least one of a second stabilizing agents having the formula
(R) 2 Si(OH) 2 wherein R is a C 6 to C 18 aromatic group,
and desolvatizing the polymer,
resulting in a polymer with stable Mooney viscosity.
2. The method of claim 1 , wherein the first stabilizing agent is a trialkylsilanol, a triarylsilanol, or mixtures thereof.
3. The method of claim 1 , wherein the second stabilizing agent is at least one diarylsilanediol.
4. The method of claim 2 , wherein the first stabilizing agent is triphenylsilanol.
5. The method of claim 2 , wherein the second stabilizing agent is diphenysilanediol.
6. The method of claim 1 , wherein the desolvatizing is performed by drum drying, direct drying, or steam desolvatizing.
7. The method of claim 1 , wherein the stabilizing agent is added to the polymer in the presence of hydrocarbon oil.
8. The method of claim 1 , wherein the initiator is butyl lithium.
9. The method of claim 1 , wherein the hydrocarbon solvent is one or more hexanes.
10. The method of claim 1 , wherein the conjugated diolefin is 1,3-butadiene.
11. The method of claim 1 , wherein the polymerizing step includes the presence of an aromatic vinyl compound.
12. The method of claim 11 , wherein the aromatic vinyl compound is styrene.
13. The method of claim 7 , wherein the hydrocarbon oil is black oil.
14. The method of claim 1 including drying the polymer after steam desolvatizing.
15. The polymer produced by the process of claim 1 .
16. A rubber composition containing a filler and the polymer of claim 15 .
17. The rubber composition of claim 16 having a 65° C. tan delta lower than the 65° C. tan delta of a rubber composition with either the first stabilizing agent or the second stabilizing agent used alone.
18. A tire comprising a sidewall and/or a tread containing the rubber of claim 16 .
19. A tire comprising a sidewall and/or a tread containing the rubber of claim 17 .