US4241203A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acrylonitrile copolymers having low residual monomer content and methods for their preparation
Assignee: Roehm GmbH Darmstadt
•
Filing: 1979-01-24
•
Granted: 1980-12-23
•
Expires: 1999-01-24
Abstract
Abstract What is disclosed are copolymers predominantly containing acrylonitrile and having a very low residual monomer content, for example of less than 100 ppm, the method of making such copolymers by polymerization to at least 60 percent conversion followed by post-heating at a temperature of more than 130 DEG C., and the use of such copolymers in orthopedic devices which come into direct contact with the skin.
Inventors
- 👤 Franz Wenzel
- 👤 Heinz-Dieter Bruemmer
- 👤 Manfred Krieg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:56
CPC Classifications
C; C08; C08F; C08F220/00; C08F220/02; C08F220/42; C08F220/44
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
88 words
The method of making a copolymer of acrylonitrile having a residual monomer content of less than 50 ppm, which comprises free-radically bulk polymerizing a monomer mixture of 60 to 80 percent by weight of acrylonitrile and 40 to 20 percent by weight of methyl methacrylate to effect a conversion of at least 75 percent by weight thereof and then further heating the resulting polymer-monomer mixture to a residual monomer content of less than 50 ppm by post-heating for 4 to 12 hours at 140° C. to 170° C.
Claim 2
Independent Claim
88 words
The method of making a copolymer of acrylonitrile having a residual monomer content of less than 50 ppm, which comprises free-radically bulk polymerizing a monomer mixture of 60 to 80 percent by weight of acrylonitrile and 40 to 20 percent by weight of methyl methacrylate to effect a conversion of at least 75 percent by weight thereof and then further heating the resulting polymer-monomer mixture to a residual monomer content of less than 50 ppm by post-heating for 4 to 12 hours at 140° C. to 170° C.
Claim 3
Dependent Claim
54 words
A method as in claim 1 wherein said monomer mixture is free-radically polymerized in the presence of at least two radical-forming initiators, one of which has a half-life of one hour at temperatures of 60° to 100° C. and a second has a half-life of one hour at temperatures of 100° to 140° C.
Claim 4
Dependent Claim
34 words
A method as in claim 2 wherein said initiator having a half-life of one hour at 100° C. to 140° C. is tert. butyl perbenzoate, tert. butyl - per-3,5,5-trimethylhexanoate, 2,2-bis-(tert. butylperoxy) butane, or dicumylperoxide.
References Cited (Backward Citations)
US2656334A
Cited
GB738473A
Cited
US2974125A
Cited
DE1083549B
Cited
US3252950A
Cited
US3847885A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-12-23 | 1984-06-23 | 1984-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-23 | 1988-06-23 | 1988-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-23 | 1992-06-23 | 1992-12-23 | $7700.00 | Window Closed / Lapsed |