US4857438A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photochromic system and layers produced therewith
Assignee: BASF SE
•
Filing: 1987-03-20
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Granted: 1989-08-15
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Expires: 2007-03-20
Abstract
Abstract A photochromic system contains an oxidizable leuco dye and a photochemically activated initiator which converts the leuco dye to the dye, the initiator being a phenanthroimidazole derivative. The photochromic system is useful for the production of photochromic layers for photoresists and printing plates.
Inventors
- 👤 Thomas Loerzer
- 👤 Reinhold J. Leyrer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 04:59
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/004; G03F7/09; G03F7/105; G03C; G03C1/00; G03C1/72; Y; Y10; Y10S; Y10S430/00; Y10S430/1053; Y10S430/1055; Y10S430/114; Y10S430/12; Y10S430/121
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
84 words
A photochromic composition containing an oxidizable leuco dye and a photochemically activated initiator which converts the leuco dye to the dye, wherein the initiator is a compound of the formula (I) or (II) ##STR12## where R 1 , R 2 , R 3 and R 4 are identical or different and are each hydrogen, alkyl, alkoxy, halogen or amino, R 5 is hydrogen, alkyl, aralkyl, alkylsulfonyl, arylsulfonyl, dialkoxyphosphoryl, dialkylphosphoryl, diarylphosphoryl or a carbonyl radical ##STR13## and R 6 is alkyl, alkoxy, phenyl or dialkylamino.
Claim 2
Dependent Claim
84 words
A photochromic composition containing an oxidizable leuco dye and a photochemically activated initiator which converts the leuco dye to the dye, wherein the initiator is a compound of the formula (I) or (II) ##STR12## where R 1 , R 2 , R 3 and R 4 are identical or different and are each hydrogen, alkyl, alkoxy, halogen or amino, R 5 is hydrogen, alkyl, aralkyl, alkylsulfonyl, arylsulfonyl, dialkoxyphosphoryl, dialkylphosphoryl, diarylphosphoryl or a carbonyl radical ##STR13## and R 6 is alkyl, alkoxy, phenyl or dialkylamino.
Claim 3
Dependent Claim
27 words
A photochromic layer which contains a photochromic composition and one or more film-forming polymers, wherein the said photochromic layer contains the photochromic composition defined in claim 1.
Claim 4
Dependent Claim
58 words
A process for the production of a lithographic layer for photoresist, offset printing, letter press printing or gravure printing or for etching glass or aluminum, wherein a photochromic layer as defined in claim 2 is subjected to actinic light through an image-bearing transparency, whereby the photochromic layer provides good color contrast between the exposed and unexposed image areas.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-08-14 | 1993-02-13 | 1993-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-14 | 1997-02-13 | 1997-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-14 | 2001-02-13 | 2001-08-15 | $7700.00 | Window Closed / Lapsed |