US3696098A
Expired / Lapsed
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Photochromic polycondensates of the indolinospiropyran type
Assignee: Agfa Gevaert NV
•
Filing: 1970-06-10
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Granted: 1972-10-03
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Expires: 1990-06-10
Abstract
Abstract A polycondensate is described having the formula WHEREIN: R represents -CH2-CH2-O-CH2-CH2-, -CH2-CH CH-CH2-, or -(CH2)n-wherein n is 2 or an integer from 4 to 10, X represents a hydrogen atom or a nitro group, and R'' represents a single bond or a methylene group. The polycondensates are photochromic and are reversibly colored upon exposure to ultraviolet radiation.
Inventors
- 👤 Jan Antonius Hoefnagels
- 👤 Norman H Hiatt
- 👤 Georges Joseph Smets
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:58
CPC Classifications
C; C08; C08G; C08G12/00; C08G12/02; C08G12/26; C07; C07D; C07D209/00; C07D209/02; C07D209/04; C07D209/08; C08G73/00; C08G73/06; C08G73/0666; C08G73/0672; G; G03; G03C; G03C1/00; G03C1/72; G03C1/73; G03C1/733
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
8 words
The polycondensate of claim 1 wherein R is
Claim 2
Dependent Claim
9 words
The polycondensate of claim 2 wherein R'' is methylene.
Claim 3
Dependent Claim
9 words
The polycondensate of claim 3 wherein X is nitro.
Claim 4
Dependent Claim
11 words
The polycondensate of claim 2 wherein R'' is a single bond.
Claim 5
Dependent Claim
9 words
The polycondensate of claim 5 wherein X is hydrogen.
Claim 6
Dependent Claim
9 words
The polycondensate of claim 1 wherein R is -CH2-CH2-O-CH2-CH2-.
Claim 7
Dependent Claim
9 words
The polycondensate of claim 7 wherein R'' is methylene.
Claim 8
Dependent Claim
9 words
The polycondensate of claim 8 wherein X is nitro.
Claim 9
Dependent Claim
10 words
The polycondensate of claim 1 wherein R is -CH2-CH CH-CH2-.
Claim 10
Dependent Claim
19 words
The polycondensate of claim 1 wherein R is -(CH2)n-wherein n is 2 or an integer from 4 to 10.
References Cited (Backward Citations)
FR1451332A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-03 | 1976-04-03 | 1976-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-03 | 1980-04-03 | 1980-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-03 | 1984-04-03 | 1984-10-03 | $7700.00 | Window Closed / Lapsed |