US4659649A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photosensitive systems showing visible indication of exposure
Assignee: Sericol Ltd
•
Filing: 1984-04-30
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Granted: 1987-04-21
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Expires: 2004-04-30
Abstract
Abstract The invention provides new compositions which change color on exposure to actinic radiation and contain a photosensitive onium, e.g. iodonium or sulphonium, salt and a dyestuff which changes color when protonated. The compositions may also include a resin, especially a resin curable by the onium salt when the latter is exposed, and preferably an epoxy resin. The compositions are useful especially as coatings, e.g. for making screen stencils or for producing lithographic printing plates.
Inventors
- 👤 Peter Dickinson
- 👤 Michael Ellwood
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:58
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/004; G03F7/09; G03F7/105; Y; Y10; Y10S; Y10S430/00; Y10S430/1053; Y10S430/1055; Y10S430/114; Y10S430/122; Y10S430/123; Y10S430/126
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
30 words
A composition which changes colour on exposure to actinic radiation comprising a photosensitive iodonium or sulphonium salt and a non-photosensitizing dyestuff which exhibits a readily visible colour change when protonated.
Claim 2
Dependent Claim
30 words
A composition which changes colour on exposure to actinic radiation comprising a photosensitive iodonium or sulphonium salt and a non-photosensitizing dyestuff which exhibits a readily visible colour change when protonated.
Claim 3
Dependent Claim
12 words
A composition according to claim 1 which also comprises a non-photoreactive vehicle.
Claim 4
Dependent Claim
17 words
A composition according to claim 1 which also comprises a photoreactive vehicle which is not cationically cured.
Claim 5
Dependent Claim
26 words
A composition according to claim 1 which also comprises a cationically curable monomer, oligomer or polymer which, at least in the cured state, is film forming.
Claim 6
Dependent Claim
18 words
A composition according to claim 4 in which the said monomer, oligomer, or polymer is an epoxy compound.
Claim 7
Dependent Claim
38 words
A composition according to claim 4, in the form of an aqueous dispersion in which the dispersed phase comprises a said cationically curable monomer, oligomer or polymer and the aqueous phase comprises a surfactant and/or a water-soluble colloid.
Claim 8
Dependent Claim
20 words
A composition according to claim 1 in which the dyestuff is a di- or tri-phenylmethane compound, or an amino-azo compound.
Claim 9
Dependent Claim
16 words
A composition according to claim 7 in which the dyestuff in N,N-bis(2-hydroxyethyl)-4-amino-azobenzene or leuco malachite green.
Claim 10
Dependent Claim
26 words
A composition according to claim 1 in which the said onium salt is an iodonium or sulphonium salt having a complex metal or metalloid halide anion.
Claim 11
Dependent Claim
32 words
A composition according to claim 9 in which the said onium salt has the anion BF 4 - , PF 6 - , AsF 6 - , or SbF 6 - .
Claim 12
Dependent Claim
11 words
A composition according to claim 1 which also contains a photosensitizer.
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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) | 1990-04-20 | 1990-10-20 | 1991-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-20 | 1994-10-20 | 1995-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-20 | 1998-10-20 | 1999-04-21 | $7700.00 | Window Closed / Lapsed |