US4812171A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Irreversible photochromic markings
Assignee: GEC-MARONI Ltd
•
Filing: 1987-06-25
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Granted: 1989-03-14
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Expires: 2007-06-25
Abstract
Abstract A photochromic ink composition which comprises a solution of a 1,2-dihydroquinoline (DHQ) in a polymer solution, the dihydroquinoline being sensitive or sensitized to ultra-violet light.
Inventors
- 👤 Jack Brettle
- 👤 Clive Trundle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:55
CPC Classifications
C; C09; C09D; C09D11/00; C09D11/50; B; B41; B41M; B41M3/00; B41M3/14; B41M3/144; C09K; C09K9/00; C09K9/02; G; G03; G03C; G03C1/00; G03C1/72; G03C1/73; G09; G09F; G09F3/00; Y; Y10; Y10T; Y10T428/00; Y10T428/31504
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
25 words
A photochromic ink composition which comprises a solution of a 1,2-dihydroquinoline (DHQ) in a polymer solution, the dihydroquinoline being sensitive or sensitised to ultra-violet light.
Claim 2
Dependent Claim
25 words
A photochromic ink composition which comprises a solution of a 1,2-dihydroquinoline (DHQ) in a polymer solution, the dihydroquinoline being sensitive or sensitised to ultra-violet light.
Claim 3
Dependent Claim
17 words
A composition according to claim 1 which is sensitised towards U.V. light by inclusion of an acid.
Claim 4
Dependent Claim
24 words
A composition according to claim 1 in which the nitrogen atom in the DHQ has an electron-withdrawing substituent, thereby rendering the composition U.V. sensitive.
Claim 5
Dependent Claim
15 words
A composition according to claim 3 in which the electron-withdrawing group is an N-acetyl group.
Claim 6
Dependent Claim
31 words
A composition according to any one of the preceding claims in which the DHQ is present in an amount of from about 0.2 to 2% by weight of the polymer solution.
Claim 7
Independent Claim
54 words
A method of applying a security or validation mark to a substrate which comprises printing a mark in an ink composition as claimed in any one of claims 1 to 4 onto the substrate and drying the ink, thereby producing a latent marking which is made visible by irradiating the substrate with U.V. light.
Claim 8
Independent Claim
48 words
A method of producing an image on a substrate which comprises forming a dried coating of a composition as claimed in any one of claims 1 to 4 on a substrate and exposing the dried coating to U.V. light through a stencil or negative to form an image.
Claim 9
Dependent Claim
23 words
A substrate having a latent validation or security marking printed thereon, said marking having been formed by the method claimed in claim 6.
References Cited (Backward Citations)
US4252879A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-03-13 | 1992-09-12 | 1993-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-13 | 1996-09-12 | 1997-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-13 | 2000-09-12 | 2001-03-14 | $7700.00 | Window Closed / Lapsed |