Low vinyl styrene-butadiene polymers and methods of making the same
First Claim
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1. A composition comprising a polymer comprising monomeric units derived from styrene and 1,3-butadiene, and wherein the polymer comprises:
- A) a vinyl content from 20 to 30 weight percent, based on the weight of polymerized butadiene in the polymer,B) a block styrene content less than 8 weight percent, based on the weight of styrene in the polymer, andC) a styrene content from 10 to 50 weight percent, based on the weight of the polymer,wherein the polymer is polymerized in the presence of a 1,2-diene, an active initiator, and at least one polar agent,wherein the 1,2-diene to active initiator molar ratio is from 0.1 to 1.0,wherein the polar agent to the active initiator molar ratio is from 0.05 to 0.6,wherein the polymer has a number average molecular weight (Mn) from 70,000 to 300,000 g/mole, wherein the composition does not comprise an oil, wherein the polar agent is ditetrahydrofurylpropane and wherein the 1,2-diene is 1,2 butadiene.
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Abstract
The invention provides a process for the continuous polymerization of a polymer comprising monomeric units derived from styrene and 1,3-butadiene, said process comprising:
- polymerizing the monomers in the presence of an initiator, and at least one polar agent selected from Formula 1;
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- wherein R1 and R2 are each independently an alkyl, and preferably a C1-C4 alkyl; R3, R4, R5, R6, R7 and R8 are each independently selected from hydrogen or an alkyl, and preferably hydrogen or a C1-C4 alkyl;
- and wherein a 1,2-diene is added to the polymerization, and the 1,2-diene to active initiator (active for polymerization) molar ratio is from 0.1 to 1.0, preferably from 0.1 to 0.9, and more preferably from 0.1 to 0.85; and
- wherein the polar agent to the active initiator molar ratio is from 0.05 to 0.6, preferably from 0.1 to 0.5, more preferably from 0.15 to 0.3.
The invention also provides a composition comprising a polymer comprising monomeric units derived from styrene and 1,3-butadiene, and wherein the polymer has at least the following characteristics:
- A) vinyl content from 12 to 40 weight percent, based on the weight of polymerized butadiene in the polymer,
- B) block styrene content less than 8 weight percent, based on the weight of styrene in the polymer, and
- C) a styrene content from 10 to 50 weight percent, based on the weight of the polymer.
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11 Claims
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1. A composition comprising a polymer comprising monomeric units derived from styrene and 1,3-butadiene, and wherein the polymer comprises:
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A) a vinyl content from 20 to 30 weight percent, based on the weight of polymerized butadiene in the polymer, B) a block styrene content less than 8 weight percent, based on the weight of styrene in the polymer, and C) a styrene content from 10 to 50 weight percent, based on the weight of the polymer, wherein the polymer is polymerized in the presence of a 1,2-diene, an active initiator, and at least one polar agent, wherein the 1,2-diene to active initiator molar ratio is from 0.1 to 1.0, wherein the polar agent to the active initiator molar ratio is from 0.05 to 0.6, wherein the polymer has a number average molecular weight (Mn) from 70,000 to 300,000 g/mole, wherein the composition does not comprise an oil, wherein the polar agent is ditetrahydrofurylpropane and wherein the 1,2-diene is 1,2 butadiene. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification