US3972933A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of carbodiimides from ureas by dehydration
Assignee: Monsanto Co
•
Filing: 1974-05-28
•
Granted: 1976-08-03
•
Expires: 1994-05-28
Abstract
Abstract Biscarbodiimides which are known to be effective as a surface application for polyethylene terephthalate fibers in lowering carboxyl end group concentration of the fibers and increasing hydrolytic stability, are prepared by the dehydration of ureas with triphenylphosphine and carbon tetrachloride.
Inventors
- 👤 Ernest L. Lawton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:22
CPC Classifications
C; C07; C07C; C07C267/00; C07C273/00; C07C273/18; C07C273/1809; C07C273/1818; C07C273/1827; D; D06; D06M; D06M13/00; D06M13/322; D06M13/395
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
14 words
The method of producing biscarbodiimides by dehydrating bisureas with triethylamine, triphenylphosphine, and carbon tetrachloride.
Claim 2
Independent Claim
14 words
The method of producing biscarbodiimides by dehydrating bisureas with triethylamine, triphenylphosphine, and carbon tetrachloride.
Claim 3
Dependent Claim
19 words
The method of claim 1 wherein the bisurea is produced by dehydration of ##SPC6## and the product is ##SPC7##
Claim 4
Dependent Claim
19 words
The method of claim 1 wherein the bisurea is produced by dehydration of ##SPC8## and the product is ##SPC9##
Claim 5
Dependent Claim
19 words
The method of claim 1 wherein the bisurea is produced by dehydration of ##SPC10## and the product is ##SPC11##
Claim 6
Dependent Claim
19 words
The method of claim 1 wherein the bisurea is produced by dehydration of ##SPC12## and the product is ##SPC13##
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) | 1979-08-03 | 1980-02-02 | 1980-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-03 | 1984-02-02 | 1984-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-03 | 1988-02-02 | 1988-08-03 | $7700.00 | Window Closed / Lapsed |