US4874829A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing α-methylstyrene-acrylonitrile polymers
Assignee: Bayer Antwerpen NV
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Filing: 1987-05-22
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Granted: 1989-10-17
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Expires: 2007-05-22
Abstract
Abstract A method of forming polymers containing alpha -methylstyrene and acrylonitrile by polymerizing, preferably continuously, under off-azeotrope conditions to vastly improve rate without substantially changing the content of alpha -methylstyrene in the polymer being formed from that obtained under azeotrope conditions.
Inventors
- 👤 Chris E. Schwier
- 👤 Wan C. Wu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:27
CPC Classifications
C; C08; C08F; C08F220/00; C08F220/02; C08F220/42; C08F220/44; C08F212/00; C08F212/02; C08F212/04; C08F212/06; C08F212/12
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
96 words
A method of forming a polymer of α-methylstyrene and acrylonitrile which comprises: polymerizing by free radical polymerization α-methylstyrene and acrylonitrile monomers, and optionally, in minor amount, one or more other monomers copolymerizable therewith, in a substantially uniform, homogenous reaction medium containing a concentration of unpolymerized α-methylstyrene which is lower by at least 5 weight % than the concentration of α-methylstyrene in the polymer being simultaneously formed, said monomers fed and said polymer withdrawn from the reaction medium continuously, the polymerization rate of said monomers being at least about 20% faster than the rate under azeotropic conditions.
Claim 2
Independent Claim
96 words
A method of forming a polymer of α-methylstyrene and acrylonitrile which comprises: polymerizing by free radical polymerization α-methylstyrene and acrylonitrile monomers, and optionally, in minor amount, one or more other monomers copolymerizable therewith, in a substantially uniform, homogenous reaction medium containing a concentration of unpolymerized α-methylstyrene which is lower by at least 5 weight % than the concentration of α-methylstyrene in the polymer being simultaneously formed, said monomers fed and said polymer withdrawn from the reaction medium continuously, the polymerization rate of said monomers being at least about 20% faster than the rate under azeotropic conditions.
Claim 3
Dependent Claim
37 words
The method of claim 1 wherein at least one monomer selected from the group consisting of maleic anhydride, imides of maleic anhydride, and C 1 to C 4 alkyl acrylates is copolymerized with the α-methylstyrene and acrylonitrile.
Claim 4
Dependent Claim
29 words
The method of claim 1 wherein the concentration of unpolymerized α-methylstyrene is more than 10 weight % less than the weight percent polymerized α-methylstyrene in the polymer being formed.
Claim 5
Dependent Claim
15 words
The method of claim 2 wherein the copolymerizable monomer is an imide of maleic anhydride.
Claim 6
Dependent Claim
11 words
The method of claim 4 wherein the imide is N-phenyl maleimide.
Claim 7
Independent Claim
38 words
The method of any of claims 1, 2, 3, 5 or 6 wherein the concentration of unpolymerized α-methylstyrene is between about 15 to about 25 weight % below the weight percent polymerized α-methylstyrene in the polymer being formed.
Claim 8
Independent Claim
50 words
A method of polymerizing α-methylstyrene and acrylonitrile which comprises continuously maintaining off-azeotrope conditions in a free radical substantially uniform, homogeneous polymerization medium wherein the weight fraction of acrylonitrile monomer is between 0.35 to 0.6 and the polymerization rate is about 20 to 100% faster than the rate under azeotropic conditions.
Claim 9
Independent Claim
50 words
A method of polymerizing α-methylstyrene and acrylonitrile which comprises continuously maintaining off-azeotrope conditions in a free radical substantially uniform, homogeneous polymerization medium wherein the weight fraction of acrylonitrile monomer is between 0.35 to 0.6 and the polymerization rate is about 20 to 100% faster than the rate under azeotropic conditions.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-10-16 | 1993-04-17 | 1993-10-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-16 | 1997-04-17 | 1997-10-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-16 | 2001-04-17 | 2001-10-17 | $7700.00 | Window Closed / Lapsed |