US3586647A
Expired / Lapsed
US
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Solid state polycondensation with porous polyester prepolymer particles
Assignee: Mobil Oil AS
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Filing: 1968-07-10
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Granted: 1971-06-22
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Expires: 1988-07-10
Abstract
Abstract POROUS PELLETS OF A POLYESTER PREPOLYMER, SUCH AS POLY(ETHYLENE TEREPHTHALATE), ARE PREPARED BY DISPERSING AN INERT GAS OR FOAMING AGENT IN A MOLTEN PREPOLYMER AND EXTRUDING AND PELLETIZING THE THUS SATURATED PREPOLYMER TO CONVENTIONAL PELLET SIZE, (1/16" TO 1/2") OR TO OTHER PARTICULATE SHAPES. THESE POROUS PARTICLES CAN BE FURTHER POLYCONDENSED IN SOLID STATE, UNDER CONVENTIONAL POLYCONDENSATION CONDITIONS, WITHOUT THE NECESSITY OF REDUCING PARTICLE SIZE BELOW 20 MESH.
Inventors
- 👤 Ross A Kremer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:37
CPC Classifications
C; C08; C08J; C08J9/00; C08J9/04; C08J9/12; C08J9/122; C08G; C08G63/00; C08G63/78; C08G63/80; C08J3/00; C08J3/12; C08J9/16; B; B29; B29B; B29B9/00; B29B9/16; B29B2009/165; C08J2367/00; C08J2367/02
Claims Analysis
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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) | 1974-06-21 | 1974-12-21 | 1975-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-21 | 1978-12-21 | 1979-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-21 | 1982-12-21 | 1983-06-22 | $7700.00 | Window Closed / Lapsed |