US4829046A
Expired / Lapsed
US
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Positive-acting thermographic materials
Assignee: Eastman Kodak Co
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Filing: 1987-10-15
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Granted: 1989-05-09
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Expires: 2007-10-15
Abstract
Abstract A positive-acting thermographic material which is black or dark colored in the unexposed condition turns white or light colored when exposed to elevated temperatures. The material comprises a binder, a dark colored complex of ferric iron with a ligand chosen from organothiophosphorus acids, and a white organophosphorus acid or its alkali or alkaline earth metal salt. At elevated temperatures a double decomposition reaction occurs giving the light colored complex of ferric iron with the organophosphorus acid.
Inventors
- 👤 David R. Whitcomb
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 20:26
CPC Classifications
B; B41; B41M; B41M5/00; B41M5/26; B41M5/30; B41M5/32; Y; Y10; Y10S; Y10S428/00; Y10S428/913
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
92 words
A positive-acting thermographic sheet comprising a substrate having coated on at least one surface thereof a coating comprising at least one layer of clear binder having independently dissolved or dispersed therein a positive-acting thermographic material comprising, in thermographically reactive association, a) a dark colored complex of ferric iron with a ligand chosen from organothiophosphates, organothiophosphinates, and organothiophosphonates, and b) a source of a moiety chosen from organophosphate, organophosphinate, and organophosphonate, said source being chosen from the group consisting of a free acid and a salt of a free acid containing said moiety.
Claim 2
Dependent Claim
92 words
A positive-acting thermographic sheet comprising a substrate having coated on at least one surface thereof a coating comprising at least one layer of clear binder having independently dissolved or dispersed therein a positive-acting thermographic material comprising, in thermographically reactive association, a) a dark colored complex of ferric iron with a ligand chosen from organothiophosphates, organothiophosphinates, and organothiophosphonates, and b) a source of a moiety chosen from organophosphate, organophosphinate, and organophosphonate, said source being chosen from the group consisting of a free acid and a salt of a free acid containing said moiety.
Claim 3
Dependent Claim
36 words
A positive-acting thermographic sheet according to claim 1, wherein said coating comprises a first and second layer of said binder, said first layer containing said complex and said second layer containing said source of said moiety.
Claim 4
Dependent Claim
26 words
A positive-acting thermographic sheet according to claim 2 wherein said coating further comprises an interlayer comprising a binder situated between said first and said second layers.
Claim 5
Dependent Claim
56 words
A positive-acting thermographic sheet according to claim 1, wherein said dark colored complex is chosen from the group defined by the general formulae ##STR4## wherein the R substituents are independently chosen from alkyl, cycloalkyl, alkaryl, and aryl, and substituted versions of these moieties providing that said substituents do not result in the creation of chelating sites.
Claim 6
Dependent Claim
82 words
A positive-acting thermographic sheet according to claim 1, wherein said source of said moiety is chosen from those having the general formulae ##STR5## wherein the R' substituents are independently chosen from alkyl, cycloalkyl, alkaryl, and aryl, and substituted versions of these substituents providing that said substituents do not result in the creation of chelating sites, and M is chosen from H, NH 4 , Na, and K, and ##STR6## wherein R' is as above, and M is chosen from Ca and Mg.
Claim 7
Dependent Claim
48 words
(New) A positive-acting thermographic sheet according to claim 1, wherein said dark colored complex is chosen from the group defined by the general formulae ##STR7## wherein the R groups are independently chosen from alkyl, cycloalkyl, alkaryl, and aryl, and substituted versions of these moieties bearing only non-chelating substituents.
Claim 8
Dependent Claim
73 words
A positive-acting thermographic sheet according to claim 1, wherein said source of said moiety of chosen from those having the general formulae ##STR8## wherein the R' groups are independently chosen from alkyl, cycloalkyl, alkaryl, and aryl, and substituted versions of these moieties bearing only non-chelating substituents, and M is chosen from H, NH 4 , Na, and K, and ##STR9## wherein R' is as above, and M is chosen from Ca and Mg.
References Cited (Backward Citations)
US2663654A
Cited
US3111423A
Cited
US3094620A
Cited
US3293055A
Cited
US3483143A
Cited
US3846153A
Cited
US3829401A
Cited
US3953659A
Cited
US4049612A
Cited
US4533930A
Cited
US4602264A
Cited
US4531141A
Cited
US4704379A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-05-08 | 1992-11-07 | 1993-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-05-08 | 1996-11-07 | 1997-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-05-08 | 2000-11-07 | 2001-05-09 | $7700.00 | Window Closed / Lapsed |