Method of making base stabilized 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 dialkoxysilane stabilizing agent is then added to the polymer in combination with a base material. 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 an alkoxysilane stabilizing agent to the polymer in combination with an alkaline earth hydroxide and/or a base material selected from the group consisting of lithium hydroxide, potassium hydroxide, sodium alkoxide, potassium alkoxide, aluminum alkoxide, ammonia, sodium hydroxide and mixtures thereof,
and desolvatizing the polymer,
resulting in a polymer with stable Mooney viscosity.
2. The method of claim 1 , wherein the alkoxysilane stabilizing agent is a dialkoxysilane.
3. The method of claim 2 including drying the polymer after desolvatizing.
4. The method of claim 1 , wherein the desolvatizing is performed by drum drying, direct drying, or steam desolvatizing.
5. The method of claim 4 , wherein the stabilizing agent is diphenyldiethoxysilane.
6. The method of claim 4 , wherein the stabilizing agent is diphenyldimethoxysilane.
7. The method of claim 1 , wherein the stabilizing agent is a diaryldialkoxysilane.
8. The method of claim 1 , wherein the initiator is n-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. A rubber composition containing a filler and the polymer of claim 11 .
14. The polymer produced by the process of claim 1 .
15. A tire comprising a sidewall and/or a tread containing the rubber of claim 14 .
16. The method of claim 1 , wherein the alkaline earth hydroxide is calcium hydroxide.
17. 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 an alkoxysilane stabilizing agent to the polymer in combination with a base material,
and desolvatizing the polymer,
resulting in a polymer with stable Mooney viscosity, wherein the base material is sodium hydroxide.