US3758425A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the preparation of foamable styrene polymers
Assignee: Hoechst AG
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Filing: 1971-11-15
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Granted: 1973-09-11
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Expires: 1991-11-15
Abstract
Abstract A PROCESS FOR PREPARING FOAMABLE STYRENE POLYMER BEADS CONTAINING BLOWING AGENTS WITH A PARTICULARLY FAVOURABLE, NARROW GRAIN SIZE DISTRIBUTION. THIS NOVEL PROCESS COMPRISES THE USE OF COPOLYMERS OF N-VINYL-N-ALKYL ACETAMIDE HAVING FROM 1 TO 4 CARBON ATOMS IN THE ALKYL GROUP WITH AN ESTER OF ACRYLIC, METHACRYLIC, MALEIC OF FUMARIC ACID WITH AN ALIPHATIC ALCOHOL HAVING A LINEAR OR BRANCHED CHAIN AND CONTAINING FROM 6 TO 18 CARBON ATOMS, AS PROTECTIVE COLLOID IN THE HOMO- OR COPOLYMERIZATION OF STYRENE IN AN AQUEOUS SUSPENSION IN THE PRESENCE OF A BLOWING AGENT.
Inventors
- 👤 E Heiskel
- 👤 H Jastrow
- 👤 M Lederer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:22
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/16; C08J9/20; C08F; C08F271/00; C08F283/00; C08F283/12; C08F283/124; Y; Y10; Y10S; Y10S526/00; Y10S526/91
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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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) | 1976-09-10 | 1977-03-12 | 1977-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-10 | 1981-03-12 | 1981-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-10 | 1985-03-12 | 1985-09-11 | $7700.00 | Window Closed / Lapsed |