US3250731A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of cellular polypropylene articles by extrusion
Assignee: Hercules Powder Co
•
Filing: 1962-10-15
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Granted: 1966-05-10
•
Expires: 1982-10-15
Abstract
No abstract record available.
Inventors
- 👤 Frank C Buhl
- 👤 George B Feild
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 01:17
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/16; C08J9/0014; C08J9/0028; C08J2323/00; C08J2323/02; C08J2323/10; C08J2323/12; Y; Y10; Y10S; Y10S264/00; Y10S264/01; Y10S264/08; Y10S264/13; Y10S264/16; Y10S264/18; Y10S8/00; Y10S8/09
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
121 words
THE PROCESS OFPREPARING EXTRUDED LOW DENSITY POLYPROPYLENE FOAMS WITH A UNIFORM CLOSED CELL STRUCTURE IN WHICH AT LEAST 50% OF THE CELLS ARE CLOSED, WHICH COMPRISES HEATING A MIXTURE OF STEREOREGULAR POLYPROPYLENE, A BLOWING AGENT WHICH YIELDS AT LEAST ONE MOLE OF GAS PER MOLE OF BLOWING AGENT AT A TEMPERATURE WITHIN THE RANGE OF FROM THE SOFTENING TEMPERATURE OF SAID MIXTURE TO ABOUT 190*C., AND FROM ABOUT 0.01% TO ABOUT 2%, BASED ON THE WEIGHT OF THE POLYPROPYLENE, OF A POLY(AZIDOFORMATE) WHICH DECOMPOSES AT A TEMPERATURE WITHIN THE RANGE OF FROM THE SOFTENING TEMPERATURE OF SAID MIXTURE TO ABOUT 190*C., IN AN EXTRUDER TO AT LEAST THE SOFTENING TEMPERATURE OF THE MIXTURE AND EXTRUDING SAID MIXTURE INTO A DESIRED SHAPE.
Claim 2
Dependent Claim
121 words
THE PROCESS OFPREPARING EXTRUDED LOW DENSITY POLYPROPYLENE FOAMS WITH A UNIFORM CLOSED CELL STRUCTURE IN WHICH AT LEAST 50% OF THE CELLS ARE CLOSED, WHICH COMPRISES HEATING A MIXTURE OF STEREOREGULAR POLYPROPYLENE, A BLOWING AGENT WHICH YIELDS AT LEAST ONE MOLE OF GAS PER MOLE OF BLOWING AGENT AT A TEMPERATURE WITHIN THE RANGE OF FROM THE SOFTENING TEMPERATURE OF SAID MIXTURE TO ABOUT 190*C., AND FROM ABOUT 0.01% TO ABOUT 2%, BASED ON THE WEIGHT OF THE POLYPROPYLENE, OF A POLY(AZIDOFORMATE) WHICH DECOMPOSES AT A TEMPERATURE WITHIN THE RANGE OF FROM THE SOFTENING TEMPERATURE OF SAID MIXTURE TO ABOUT 190*C., IN AN EXTRUDER TO AT LEAST THE SOFTENING TEMPERATURE OF THE MIXTURE AND EXTRUDING SAID MIXTURE INTO A DESIRED SHAPE.
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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) | 1969-05-09 | 1969-11-08 | 1970-05-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-05-09 | 1973-11-08 | 1974-05-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-05-09 | 1977-11-08 | 1978-05-10 | $7700.00 | Window Closed / Lapsed |