Patent US3756989A successfully refreshed from Google Patents.
US3756989A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Novel polyethylene terephthalate catalysts
Assignee: Arkema Inc
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Filing: 1971-03-15
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Granted: 1973-09-04
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Expires: 1991-03-15
Abstract
Abstract A PROCESS FOR PREPARING POLYETHYLENE TEREPHTHALTE WHEREIN DIMETHYL TEREPHTHALATE IS REACTED WITH ETHYLENE GLYCOL TO FORM AN ESTER OF ETHYLENE GLYCOL AND TEREPHTHALIC ACID OR WHERE TEREPHTHALIC ACID IS REACTED WITH ETHYLENE GLYCOL TO FORM AN ESTER OF TEREPHTHALIC ACID AND ETHYLENE GLYCLO WHERE THE RESULTING ESTER IS POLYCONDENSED IN THE PRESENCE OF A POLYCONDENSATION CATALYST, THE IMPROVEMENT COMPRISING CARRYING OUT THE CONDENSATION OR POLYMERIZATION OF THE ESTER IN THE PRESENCE OF A CATALYTIC AMOUNT OF SPECIFIED TRIVALENT ANTIMONY COMPOUNDS CONTAINING THREE ANTIMONY SULFUR BONDS.
Inventors
- 👤 J Mackey
- 👤 J Ventura
- 👤 M Gitlitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 02:41
CPC Classifications
G; G01; G01K; G01K3/00; G01K3/005
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) | 1976-09-03 | 1977-03-05 | 1977-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-03 | 1981-03-05 | 1981-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-03 | 1985-03-05 | 1985-09-04 | $7700.00 | Window Closed / Lapsed |