US3751377A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for the preparation of plastic foam
Assignee: Dow Chemical Co
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Filing: 1971-08-19
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Granted: 1973-08-07
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Expires: 1991-08-19
Abstract
Abstract THERMOPLASTIC FOAM IS PREPARED BY EXTRUSION AND INJECTION OF A FLUID BLOWING AGENT INTO THE HEAT PLASTIFIED MASS. THE IMPROVEMENT IS THE INCLUSION OF AN INTERFACIAL SURFACE GENERATOR; THAT IS, MOTIONLESS IN-LINE MIXER, WHOSE MIXING, UNDER CONDITIONS OF STREAM-LINE FLOW, CAN BE CONSIDERED INDEPENDENT OF THROUGHPUT. FOAMS OF REDUCED DENSITY AND INCREASED HOMOGENEITY ARE OBTAINED. LOWER POWER IS REQUIRED, TOGETHER WITH SIMPLIFIEED EQUIPMENT AND REDUCED MAINTENANCE THEREOF. D R A W I N G
Inventors
- 👤 M Buckner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:11
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/34; B29C44/36; B29C44/46; B29C44/50; B29C48/00; B29C48/25; B29C48/36; B29C48/362; B29C48/03; B29C48/06; Y; Y10; Y10S; Y10S264/00; Y10S264/13; Y10S264/17; Y10S521/00; Y10S521/91
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) | 1976-08-06 | 1977-02-05 | 1977-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-06 | 1981-02-05 | 1981-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-06 | 1985-02-05 | 1985-08-07 | $7700.00 | Window Closed / Lapsed |