Method of making 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 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 is then added to the polymer, optionally in the presence of hydrocarbon oil. The polymer is then desolvatizing, 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 stabilizing agent to the polymer 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 nitrogen or oxygen heteroatom, C 4 to C 8 cycloalkyl, or C 6 to C 18 aromatic group, n is 1 or 2,
and desolvatizing the polymer,
resulting in a polymer with stable Mooney viscosity and wherein the stabilizing agent is added to the polymer in the presence of black oil.
2. The method of claim 1 , wherein the stabilizing agent is a trialkylsilanol, triarylsilanol, or diarylsilanediol.
3. The method of claim 1 , wherein the stabilizing agent is a triarylsilanol.
4. The method of claim 3 , wherein the stabilizing agent is triphenylsilanol.
5. The method of claim 1 , wherein the desolvatizing is performed by drum drying, direct drying, or steam desolvatizing.
6. The method of claim 1 , wherein the stabilizing agent is added to the polymer in the presence of hydrocarbon oil.
7. The method of claim 1 , wherein the initiator is butyl lithium.
8. The method of claim 1 , wherein the hydrocarbon solvent is one or more hexanes.
9. The method of claim 1 , wherein the conjugated diolefin is 1, 3-butadiene.
10. The method of claim 1 , wherein the polymerizing step includes the presence of an aromatic vinyl compound.
11. The method of claim 10 , wherein the aromatic vinyl compound is styrene.
12. The method of claim 1 including drying the polymer after steam desolvatizing.
13. The polymer produced by the process of claim 1 .
14. A rubber composition containing a filler and the polymer of claim 1 .
15. A tire comprising a sidewall and/or a tread containing the rubber of claim 14 .