US4098973A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Compounds and process
Assignee: Pharmacia and Upjohn Co
•
Filing: 1977-01-31
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Granted: 1978-07-04
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Expires: 1997-01-31
Abstract
Abstract Modified polystyrenes are described which are catalysts for the conversion of organic isocyanates to the corresponding carbodiimides. The modified polystyrenes are characterized by the presence of recurring units of the formula: ##STR1## R 1 and R 2 are hydrocarbyl which is free of substituents reactive with isocyanate groups, R 3 is hydrogen, chloro or methyl, R 4 is hydrogen or methyl, and n is 0 or 1. The use of the above polymers to catalyze the formation of carbodiimides from organic isocyanates is also disclosed.
Inventors
- 👤 Curtis P. Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:25
CPC Classifications
B; B01; B01J; B01J31/00; B01J31/02; B01J31/06; B01J31/069; C; C08; C08F; C08F8/00; C08F8/42
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
67 words
A polymer characterized by the presence therein of a recurring unit having the formula: ##STR8## wherein n is 0 or 1, R 1 and R 2 each independently represents hydrocarbyl, said hydrocarbyl being free of substituents which are reactive with isocyanate, R 3 is selected from the class consisting of chlorine, methyl and hydrogen and R 4 is selected from the class consisting of hydrogen and methyl.
Claim 2
Dependent Claim
67 words
A polymer characterized by the presence therein of a recurring unit having the formula: ##STR8## wherein n is 0 or 1, R 1 and R 2 each independently represents hydrocarbyl, said hydrocarbyl being free of substituents which are reactive with isocyanate, R 3 is selected from the class consisting of chlorine, methyl and hydrogen and R 4 is selected from the class consisting of hydrogen and methyl.
Claim 3
Dependent Claim
36 words
A polymer according to claim 1 wherein the remainder of the recurring units present in said polymer are those of the formula: ##STR9## wherein R 3 and R 4 have the significance defined in claim 1.
Claim 4
Dependent Claim
15 words
A polymer according to claim 1 wherein R 1 and R 2 each represent phenyl.
References Cited (Backward Citations)
US3970603A
Cited
US3995094A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-07-03 | 1982-01-02 | 1982-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-03 | 1986-01-02 | 1986-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-03 | 1990-01-02 | 1990-07-04 | $7700.00 | Window Closed / Lapsed |