US4764572A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Anionic polymerization process
Assignee: Kraton Polymers US LLC
•
Filing: 1985-07-23
•
Granted: 1988-08-16
•
Expires: 2005-07-23
Abstract
Abstract This invention provides an improvement in anionic polymerization processes which comprise both a batch polymerization step to form and partially grow living polymer chains and a subsequent continuous or semi-continuous step in which growth of the chains is continued. For purposes of this improvement, the transition to the continuous or semi-continuous step takes place before the molar concentration of monomer in the batch polymerization step is depleted to a level below that of the living chains. Anionic polymerization processes are recognized as particularly useful for the production of polymers having narrow molecular weight distributions. Practice under the invention is found to enhance the narrow distribution of the polymer product by controlling thermal die-out of chains which has occurred in conventional processes during the transition from batch to continuous or semi-continuous polymerization steps.
Inventors
- 👤 Arthur R. Bean, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 13:44
CPC Classifications
C; C08; C08F; C08F2/00; C08F2/04; C08F297/00; C08F297/02; C08F297/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
177 words
In an anionic polymerization process for the preparation of block copolymers which comprises steps for (a) contacting and reacting in a batch mode and at a temperature of at least about 50° C. a charge of a first monomer selected from the group consisting of butadiene, isoprene, styrene, and mixtures thereof and a charge of anionic polymerization initiator, and (b) subsequently contacting and reacting in a continuous or semi-continuous mode the product of step (a) with a charge of a second monomer selected from the group consisting of butadiene, isoprene, styrene, and mixtures thereof, said second monomer being a different monomer than the said first monomer, to continue the anionic polymerization reaction, the improvement which comprises commencing continuous or semi-continuous step (b) by addition of the second monomer to the product of batch step (a) when the first monomer conversion in step (a) reaches a level between about 99 and 99.9 percent, and while the molar ratio of the unreacted first monomer in step (a) to the initiator charge to step (a) remains at least about 1:1.
Claim 2
Dependent Claim
177 words
In an anionic polymerization process for the preparation of block copolymers which comprises steps for (a) contacting and reacting in a batch mode and at a temperature of at least about 50° C. a charge of a first monomer selected from the group consisting of butadiene, isoprene, styrene, and mixtures thereof and a charge of anionic polymerization initiator, and (b) subsequently contacting and reacting in a continuous or semi-continuous mode the product of step (a) with a charge of a second monomer selected from the group consisting of butadiene, isoprene, styrene, and mixtures thereof, said second monomer being a different monomer than the said first monomer, to continue the anionic polymerization reaction, the improvement which comprises commencing continuous or semi-continuous step (b) by addition of the second monomer to the product of batch step (a) when the first monomer conversion in step (a) reaches a level between about 99 and 99.9 percent, and while the molar ratio of the unreacted first monomer in step (a) to the initiator charge to step (a) remains at least about 1:1.
Claim 3
Dependent Claim
25 words
The process of claim 1, wherein step (b) is commenced while the molar ratio of unreacted first monomer to initiator remains at least about 2:1.
Claim 4
Dependent Claim
25 words
the process of claim 2, wherein step (b) is commenced while the molar ratio of unreacted first monomer to initiator remains at least about 4:1.
Claim 5
Dependent Claim
17 words
The process of claim 1, wherein the first monomer is styrene and the second monomer is butadiene.
Claim 6
Dependent Claim
17 words
The process of claim 2, wherein the first monomer is styrene and the second monomer is butadiene.
References Cited (Backward Citations)
US27145A
Cited
US3248377A
Cited
US3356763A
Cited
US3488332A
Cited
US3449306A
Cited
DE2011561A1
Cited
USRE27145E
Cited
US3687913A
Cited
DE2134656A1
Cited
US3801555A
Cited
EP0002012A1
Cited
US4239870A
Cited
US4530966A
Cited
US4390663A
Cited
US4371661A
Cited
US4480075A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-08-16 | 1992-02-15 | 1992-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-16 | 1996-02-15 | 1996-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-16 | 2000-02-15 | 2000-08-16 | $7700.00 | Window Closed / Lapsed |