Patent US4061836A successfully refreshed from Google Patents.
US4061836A
Expired / Lapsed
US
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Thermographic recording system
Assignee: Saint Gobain Performance Plastics Corp
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Filing: 1976-04-13
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Granted: 1977-12-06
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Expires: 1996-04-13
Abstract
Abstract Thermorecording sheet, thermorecording method and method of manufacture of a thermally responsive recording paper comprising a reversibly reduced cyclic polyketo compound, such as hydrindantin and an N,N' polythiodiamine having a sulfur chain length of at least two sulfur atoms.
Inventors
- 👤 Albert P. Yundt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 21:00
CPC Classifications
B; B41; B41M; B41M5/00; B41M5/26; B41M5/30; B41M5/323; Y; Y10; Y10S; Y10S428/00; Y10S428/913
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
34 words
A thermally responsive recording sheet comprising a substrate and a thermally responsive coating on the substrate comprising, in a reversibly reduced form, a cyclic polyketo compound, color reactive with amines, and an N,N' polythiodiamine.
Claim 2
Dependent Claim
34 words
A thermally responsive recording sheet comprising a substrate and a thermally responsive coating on the substrate comprising, in a reversibly reduced form, a cyclic polyketo compound, color reactive with amines, and an N,N' polythiodiamine.
Claim 3
Dependent Claim
17 words
A recording sheet in accordance with claim 1 wherein said reversibly reduced cyclic polyketo compound is hydrindantin.
Claim 4
Dependent Claim
35 words
A recording sheet in accordance with claim 2 wherein said substrate is paper, wherein said coating includes an organopolymeric binder and wherein said hydrindantin and said N,N' polythiodiamine are each present in finely divided form.
Claim 5
Dependent Claim
26 words
A recording sheet in accordance with claim 3 wherein said N,N' polythiodiamine comprises an N,N' polythiodiamine having a sulfur chain of more than two sulfur atoms.
Claim 6
Dependent Claim
15 words
A recording sheet in accordance with claim 4 wherein said hydrindantin is in hydrated form.
Claim 7
Dependent Claim
15 words
A recording sheet in accordance with claim 3 wherein said hydrindantin is in hydrated form.
Claim 8
Dependent Claim
17 words
A recording sheet in accordance with claim 3 wherein said organopolymeric binder is a water soluble polymer.
Claim 9
Dependent Claim
27 words
A recording sheet in accordance with claim 7 wherein said water soluble polymer is selected from the group consisting of polyvinyl alcohol, methyl cellulose, and hydroxypropyl cellulose.
Claim 10
Dependent Claim
84 words
In a method for recording on a thermally responsive sheet employing selective thermal activation of an amine-polyketo color compound system to produce a visible mark, the improvement comprising conducting, upon said thermal activation, a redox reaction between a cyclic polyketo compound in reversibly reduced form and an N,N' polythiodiamine to reductively decompose said N,N' polythiodiamine and to oxidize said reduced polyketo compound to provide, respectively, cyclic polyketo compound and reactive amine components of an amine-cyclic polyketo color compound system responsive to said thermal activation.
Claim 11
Dependent Claim
84 words
In a method for recording on a thermally responsive sheet employing selective thermal activation of an amine-polyketo color compound system to produce a visible mark, the improvement comprising conducting, upon said thermal activation, a redox reaction between a cyclic polyketo compound in reversibly reduced form and an N,N' polythiodiamine to reductively decompose said N,N' polythiodiamine and to oxidize said reduced polyketo compound to provide, respectively, cyclic polyketo compound and reactive amine components of an amine-cyclic polyketo color compound system responsive to said thermal activation.
Claim 12
Dependent Claim
24 words
A method in accordance with claim 9 wherein said N,N' polythiodiamine comprises N,N' polythiodipiperidine having a sulfur chain length of from 4 to 6.
Claim 13
Dependent Claim
26 words
A method in accordance with claim 9 wherein said N,N' polythiodiamine comprises an N,N' polythiodiamine having a sulfur chain length of more than two sulfur atoms.
Claim 14
Dependent Claim
16 words
A method in accordance with claim 11 wherein said reversibly reduced polyketo compound comprises hydrated hydrindantin.
Claim 15
Independent Claim
54 words
A method of manufacturing a thermally responsive recording paper, comprising, providing an aqueous coating dispersion of finely divided hydrindantin and finely divided N,N' polythiodiamine in an aqueous solution or dispersion of a suitable water soluble or dispersable binder material, coating a base paper substrate with said aqueous coating dispersion, and drying said coated paper.
Claim 16
Independent Claim
54 words
A method of manufacturing a thermally responsive recording paper, comprising, providing an aqueous coating dispersion of finely divided hydrindantin and finely divided N,N' polythiodiamine in an aqueous solution or dispersion of a suitable water soluble or dispersable binder material, coating a base paper substrate with said aqueous coating dispersion, and drying said coated paper.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-12-05 | 1981-06-06 | 1981-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-12-05 | 1985-06-06 | 1985-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-12-05 | 1989-06-06 | 1989-12-06 | $7700.00 | Window Closed / Lapsed |