Preparation of branched block copolymers

C - Chemistry – Metallurgy – 08 – F

Patent

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

400/2042

C08F 297/04 (2006.01)

Patent

CA 1180840

Abstract of the disclosure: A process for the preparation of branched block copolymers of from 60 to 95 % by weight of a monovinyl-aromatic monomer and from 40 to 5 % by weight of a conjugated diene by polymerizing the monomers in an inert solvent in the presence of a monolithium- hydrocarbon as the initiator, wherein, in a first process stage (a), from 50 to 80, or where necessary at most 90, % by weight of the total amount of monovinyl-aromatic compound are polymerized to virtually complete conversion in the presence of a relatively small amount of the mono- lithium-hydrocarbon. This stage is carried out by starting with from 30 to 70 % by weight of the vinyl- aromatic monomer and adding from 70 to 30 % by weight in the feed, during the polymerization, in such a way that the polymerization temperature, which at the start of the polymerization is from 30 to 40°C, is kept at from 45 to 70°C, with use of reflux cooling. After all the monomer feed has been added the reaction temperature is lowered to 30- 40°C by evaporative cooling. In a second process stage (b), an additional amount of initiator is added to the reaction solution, after which from 1 to 30 % by weight of the total amount of monovinyl-aromatic monomer can be added, the sum of the amounts of monovinyl- aromatic monomer added in the first and second process stages being at most 90 % by weight of the total amount of monovinyl-aromatic monomer. The monovinyl-aromatic monomer added in the second process stage is polymerized to virtually complete conversion, employing the tempera- ture profile described for stage (a). In process stage (c), the remainder of the monovinyl-aromatic monomer and all of the conjugated diene are added, at least predominantly in the form of a mixture, and poly- merized so that the reaction temperature does not rise above 90 - 110°C. Finally, after virtually complete conversion of the monomers, and preferably without prior cooling, a suitable liquid polyfunctional coupling agent is run in undiluted and the mixture of the linear block copolymers obtained, which still contain active terminal lithium-carbon bonds, is coupled, with stirring, to form branched block copolymers. The products prepared according to the invention are used for injection molding.

383818

LandOfFree

Say what you really think

Search LandOfFree.com for Canadian inventors and patents. Rate them and share your experience with other people.

Rating

Preparation of branched block copolymers does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Preparation of branched block copolymers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Preparation of branched block copolymers will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFCA-PAI-O-1238089

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.