US3346542A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Addition of calcium hexafluorosilicate or hexafluorosilicic acid as haze inhibitor during two-stage catalytic production of polyethylene terephthalate
Assignee: Glanzstoff AG
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Filing: 1964-03-02
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Granted: 1967-10-10
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Expires: 1984-03-02
Abstract
No abstract record available.
Inventors
- 👤 Koepp Hans-Martin
- 👤 Siggel Erhard
- 👤 Roedel Hilmar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:01
CPC Classifications
C; C08; C08G; C08G63/00; C08G63/78; C08G63/82; C08G63/83; C08G63/87
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
98 words
IN THE PRODUCTION OF POLYETHYLENE TEREPHTHALATE BY A FIRST STAGE ESTER-INTERCHANGE BETWEEN DIMETHYL TEREPHTHALATE AND ETHYLENE GLYCOL IN THE PRESENCE OF AN ALKALINE EARTH METAL TRANSETERIFICATION CATALYST FOLLOWED BY A SECOND STAGE CATALYTIC POLYCONDENSATION OF THE RESULTING DIGLYCOL TEREPHTHALATE, THE IMPROVEMENT WHICH COMPRISES: CARRYING OUT SAID SECOND STAGE POLYCONDENSATION IN THE PRESENCE OF A POLYCONDENSATION CATALYST WHILE INTRODUCING AS A HAZE INHIBITOR AFTER SUBSTANTIAL COMPLETION OF SAID TRANSESTERIFICATION AT LEAST ABOUT 0.001 MOL PERCENT, WITH REFERENCE TO THE INITIAL DIMETHYL TEREPHTHALATE, OF AN ADDITIVE SELECTED FROM THE GROUP CONSISTING OF HEXAFLUOROSILICIC ACID AND CALCIUM HEXAFLURORSILICATE AND MIXTURES THEREOF.
Claim 2
Dependent Claim
98 words
IN THE PRODUCTION OF POLYETHYLENE TEREPHTHALATE BY A FIRST STAGE ESTER-INTERCHANGE BETWEEN DIMETHYL TEREPHTHALATE AND ETHYLENE GLYCOL IN THE PRESENCE OF AN ALKALINE EARTH METAL TRANSETERIFICATION CATALYST FOLLOWED BY A SECOND STAGE CATALYTIC POLYCONDENSATION OF THE RESULTING DIGLYCOL TEREPHTHALATE, THE IMPROVEMENT WHICH COMPRISES: CARRYING OUT SAID SECOND STAGE POLYCONDENSATION IN THE PRESENCE OF A POLYCONDENSATION CATALYST WHILE INTRODUCING AS A HAZE INHIBITOR AFTER SUBSTANTIAL COMPLETION OF SAID TRANSESTERIFICATION AT LEAST ABOUT 0.001 MOL PERCENT, WITH REFERENCE TO THE INITIAL DIMETHYL TEREPHTHALATE, OF AN ADDITIVE SELECTED FROM THE GROUP CONSISTING OF HEXAFLUOROSILICIC ACID AND CALCIUM HEXAFLURORSILICATE AND MIXTURES THEREOF.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1970-10-09 | 1971-04-10 | 1971-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-10-09 | 1975-04-10 | 1975-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-10-09 | 1979-04-10 | 1979-10-10 | $7700.00 | Window Closed / Lapsed |