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US 6,444,755 B1Granted
Conjugated diene/monovinylarene block copolymers blends
AssigneePhillips Petroleum Company
InventorsCraig D. DePorter, Nathan E. Stacy, George A. Moczygemba
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Abstract
A block copolymer comprising at least three consecutive conjugated diene/monovinylarene tapered blocks is provided. Other aspects of this invention include a polymerization process for preparing the block copolymer and polymer blends comprising the block copolymer. The block copolymer and polymer blends exhibit excellent optical and mechanical properties.
Claims5
A polymer blend comprising a coupled conjugated diene/monovinylarene block copolymer and a styrenic polymer;
- wherein said coupled conjugated diene/monovinylarene block copolymer is produced by the process comprising:
- sequentially contacting under polymerization conditions at least one monovinylarene monomer, an organomonoalkali metal initiator, at least one conjugated diene monomer, and thereafter coupling with a polyfunctional coupling agent to form the block copolymer;
- wherein at least three consecutive monomer mixture charges containing monovinlyarene monomer and conjugated diene monomer are provided to produce at least three consecutive conjugated diene/monovinylarene tapered blocks in the block copolymer, wherein all the monovinylarene monomer and conjugated diene monomer contained in each charge is added at the beginning of the charge allowing excess monomer to be present in the reactor, wherein the at least one monovinylarene monomer contains from 8 to 18 carbon atoms;
- and wherein the at least one conjugated diene monomer contains from 4 to 12 carbon atoms.
1 more element
Dependencies are inferred from the claim text.