US4540754A
Expired / Lapsed
US
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Process for producing high molecular weight acrylonitrile polymers
Assignee: Toyobo Co Ltd
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Filing: 1984-03-26
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Granted: 1985-09-10
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Expires: 2004-03-26
Abstract
Abstract In the suspension polymerization of acrylonitrile in an aqueous medium, the polymerization is conducted in the presence of a water-soluble polymer and an oil soluble radical initiator while maintaining the acrylonitrile concentration higher than 9 weight percent in the polymerization system, whereby the polymerization of acrylonitrile in the water phase is suppressed and a high molecular weight polymer (weight average molecular weight not less than 400,000) having uniform particle diameters is produced.
Inventors
- 👤 Toshiyuki Kobashi
- 👤 Shoyo Takagi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 01:21
CPC Classifications
C; C08; C08F; C08F20/00; C08F20/02; C08F20/42; C08F20/44; C08F2/00; C08F2/12; C08F2/16; C08F2/18
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
112 words
A method of producing a high molecular weight acrylonitrile polymer having a weight average molecular weight not less than 400,000, characterized by suspension-polymerizing at a temperature of from 20° to 80° C., acrylonitrile alone or a monomer mixture compound of more than 85 weight % acrylonitrile and at least one other ethylenically unsaturated monomer which forms the remainder, in an aqueous medium containing a water-soluble polymer and an oil-soluble radical initiator, under the conditions that an acrylonitrile concentration higher than 9 weight % is maintained in the polymerization system, and wherein the effect of stirring imparted to the polymerization system is 1-10 KWH/m 3 in terms of the power required for stirring.
Claim 2
Independent Claim
112 words
A method of producing a high molecular weight acrylonitrile polymer having a weight average molecular weight not less than 400,000, characterized by suspension-polymerizing at a temperature of from 20° to 80° C., acrylonitrile alone or a monomer mixture compound of more than 85 weight % acrylonitrile and at least one other ethylenically unsaturated monomer which forms the remainder, in an aqueous medium containing a water-soluble polymer and an oil-soluble radical initiator, under the conditions that an acrylonitrile concentration higher than 9 weight % is maintained in the polymerization system, and wherein the effect of stirring imparted to the polymerization system is 1-10 KWH/m 3 in terms of the power required for stirring.
Claim 3
Dependent Claim
18 words
The method as claimed in claim 1 wherein an azo compound is used as the oil-soluble radical initiator.
Claim 4
Dependent Claim
16 words
The method as claimed in claim 1 wherein polyvinyl alcohol is used as the water-soluble polymer.
Claim 5
Dependent Claim
17 words
The method as claimed in claim 2 wherein 2,2'-azobisisobutyronitrile or 2,2'-azobis(2,4-dimethylvaleronitrile) is used as the azo compound.
Claim 6
Dependent Claim
29 words
The method as claimed in claim 3 wherein as the polyvinyl alcohol, a partially saponified polyvinyl alcohol having a degree of saponification of from 85 to 95% is used.
Claim 7
Dependent Claim
20 words
The method as claimed in claim 1 wherein the weight average molecular weight of the polymer is more than 1,000,000.
Claim 8
Dependent Claim
28 words
The method as claimed in claim 1 wherein the water-soluble polymer is maintained in the polymerization system in an amount of 0.5-3% based on the total monomer weight.
Claim 9
Dependent Claim
21 words
The method as claimed in claim 4 wherein 0.5-2.5% 2,2'-azobisisobutyronitrile or 0.1-0.5% 2,2'-azobis(2,4-dimethylvaleronitrile) based on the total monomer weight is used.
Claim 10
Dependent Claim
21 words
The method as claimed in claim 8 wherein 0.2-1.5% 2,2'-azobisisobutyronitrile or 0.02-0.3% 2,2'-azobis(2,4-dimethylvaleronitrile) based on the total monomer weight is used.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-09-09 | 1989-03-11 | 1989-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-09 | 1993-03-11 | 1993-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-09 | 1997-03-11 | 1997-09-10 | $7700.00 | Window Closed / Lapsed |