US3665052A
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Method of preparing a block copolymer containing a poly-alpha-methylstyrene block and a polydiorganosiloxane block
Assignee: Dow Silicones Corp
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Filing: 1970-08-25
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Granted: 1972-05-23
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Expires: 1990-08-25
Abstract
Abstract Block copolymers containing a poly-alpha-methylstyrene block and a polydiorganosiloxane block are prepared by polymerizing alphamethylstyrene with a lithium initiator at about -70* C., a small amount of styrene is then added and polymerized onto the polyalpha-methylstyrene before the temperature is raised to ambient temperature to polymerize polydiorganocyclosiloxanes and forming a block copolymer having the stated blocks. The block copolymers can vary from thermoplastic materials to elastomers.
Inventors
- 👤 John C Saam
- 👤 Frederick W G Fearon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:23
CPC Classifications
C; C08; C08G; C08G77/00; C08G77/42; C08G77/442
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-23 | 1975-11-22 | 1976-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-23 | 1979-11-22 | 1980-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-23 | 1983-11-22 | 1984-05-23 | $7700.00 | Window Closed / Lapsed |