US3674828A
Expired / Lapsed
US
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Preparation of liquid diphenylmethane diisocyanate compositions
Assignee: Imperial Chemical Industries Ltd
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Filing: 1969-05-02
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Granted: 1972-07-04
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Expires: 1989-05-02
Abstract
Abstract A process for the manufacture of a liquid diphenylmethane diisocyanate composition which comprises heating at elevated temperature, a diphenylmethane diisocyanate which is solid or partially solid at 15* C., and a N,N''-disubstituted thiourea or N1,N4-disubstituted-bis-thiourea in an amount of from 0.25 to 20 percent by weight of the diphenylmethane diisocyanate and distilling out an isothiocyanate from the heated mixture.
Inventors
- 👤 Martin Frederick Brooks
- 👤 Vincent Kerrigan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 06:01
CPC Classifications
C; C07; C07C; C07C263/00; C07C263/18
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
25 words
Process as claimed in claim 1 wherein the amount of substituted thiourea is from 1.0 to 5.0 percent of the weight of the diphenylmethane diisocyanate.
Claim 2
Dependent Claim
21 words
Process as claimed in claim 1 wherein heating is carried out at a temperature of from 40* C. to 250* C.
Claim 3
Dependent Claim
31 words
Process as claimed in claim 6 wherein the temperature is from 50* to 200* C. and heating is carried out under a pressure of from 200 mm to 1 mm Hg.
Claim 4
Dependent Claim
117 words
Process for the manufacture of a liquid diphenylmethane composition which comprises heating a diphenylmethane diisocyanate which is solid or partially solid at 15* C., with an N,N''-disubstituted thiourea of the formula R-NHCS-NHR'' or an N1, N4-disubstituted-bis-thiourea of the formula R-NHCSNH-X-NHCSNHR'' wherein R and R'' represent phenyl radicals optionally substituted with a methyl, chloro, methoxy or nitro substituent, alkyl radicals with one to four carbon atoms, benzyl or a cyclohexyl radical and X represents a divalent alkyl radical containing two to six carbon atoms, in an amount of from 0.25 to 20 percent by weight of the diphenylmethane diisocyanate at a temperature within the range 40* to 250* C. and distilling out an isothiocyanate from the heated mixture.
Claim 5
Dependent Claim
88 words
A liquid diphenylmethane diisocyanate composition made by a process comprising heating at elevated temperature, a diphenylmethane -4,4''-disubstituted-bis-thiourea of the formula R-NHCSNH-X-NHCSNHR'' wherein R and R'' represent phenyl radicals optionally substituted with a methyl, chloro, methoxy or nitro substituent, alkyl radicals with one to four carbon atoms, benzyl or a cyclohexyl radical and X represents a divalent alkyl radical containing two to six carbon atoms, in an amount of from 0.25 to 20 percent by weight of the diphenylmethane diisocyanate and distilling out an isothiocyanate during the heating step.
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) | 1975-07-04 | 1976-01-03 | 1976-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-04 | 1980-01-03 | 1980-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-04 | 1984-01-03 | 1984-07-04 | $7700.00 | Window Closed / Lapsed |