US4399188A
Expired / Lapsed
US
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Heat-sensitive recording sheet
Assignee: Nippon Paper Industries Co Ltd
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Filing: 1981-06-29
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Granted: 1983-08-16
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Expires: 2001-06-29
Abstract
Abstract A heat-sensitive recording sheet containing in its color-forming layer a colorless or pale colored chromogenic fluoran-type dyestuff and p-hydroxybenzoic acid ester having the following general formula ##STR1## wherein R represents ##STR2## This heat-sensitive recording sheet incorporates high image density and very preferable recording aptitude with less abrasiveness and less residues accumulated even for long time recording. Furthermore, a phenol substance having a melting point of more than 90° C. and a solubility of less than 0.1 g per 100 g water, which is used together with said p-hydroxybenzoic acid ester, is useful for lowering the yellowing of the heat-sensitive sheet.
Inventors
- 👤 Noboru Yamato
- 👤 Tosimi Satake
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 01:06
CPC Classifications
B; B41; B41M; B41M5/00; B41M5/26; B41M5/30; B41M5/333; B41M5/3333; B41M5/3335; Y; Y10; Y10S; Y10S428/00; Y10S428/913
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
49 words
A heat-sensitive recording sheet having a microcapsule-free color forming layer comprising a colorless or pale-colored chromogenic fluoran type dyestuff and a color-developing agent causes color development only at an elevated temperature, said color-developing agent comprising a p-hydroxybenzoic acid ester having the following general formula ##STR7## wherein R represents ##STR8##
Claim 2
Dependent Claim
49 words
A heat-sensitive recording sheet having a microcapsule-free color forming layer comprising a colorless or pale-colored chromogenic fluoran type dyestuff and a color-developing agent causes color development only at an elevated temperature, said color-developing agent comprising a p-hydroxybenzoic acid ester having the following general formula ##STR7## wherein R represents ##STR8##
Claim 3
Dependent Claim
64 words
The heat-sensitive recording sheet according to claim 1, wherein said color-developing agent contains a phenolic substance, which resists yellowing, having a melting point of more than 90 degrees C, a solubility of less than 0.1 g per 100 g water, a specific gravity of 0.9-1.15, and has no color-developing ability in the presence of said fluoran-type color-formers, in addition to said p-hydroxybenzoic acid ester.
Claim 4
Dependent Claim
14 words
The heat-sensitive recording sheet according to claim 2, wherein said phenolic substance is 4,4'-butylidene-bis(3-methyl-6-tertiary-butylphenol).
Claim 5
Dependent Claim
41 words
The heat-sensitive recording sheet according to claim 2, wherein said phenolic substance is at least one substance selected from the group consisting of 2,2'-methylene-bis(4-methyl-6-tertiary-butylphenol), 2,5-di-tertiary-butyl-hydroquinone, 2,5-di-tertiary-amyl-hydroquinone, 1,1'-bis(4-hydroxy-phenyl) cyclohexane, 2,6-bis(2'-hydroxy-3'-tertiary-butyl-5-methylbenzyl)-4-methylphenol, 2,2'-methylene-bis(4-ethyl-6-tertiary-butylphenol), 2,2'-isobutylidene-bis(4,6-dimethylphenol), 1'-oxy-3-methyl-4-isopropylbenzene, 2-hydroxy-4-benzyloxy-benzophenone, bis-[3,3'-bis(4'-hydroxy-3'-tertiary-butylphenol)-butyric acid]glycol ester, bis(3-methyl-4-hydroxy-5-tertiary-butyl-benzyl) sulfide, 2,2'-methylene-bis(4-methyl-6-cyclohexylphenol) and hydroquinone-mono-benzylether.
Claim 6
Dependent Claim
94 words
The heat-sensitive recording sheet according to claim 2, wherein said color-forming layer comprises 1 part by weight of said colorless or pale-colored chromogenic fluoran type dyestuff, from about 3 to about 10 parts by weight of said p-hydroxybenzoic acid ester, from about 1 to about 5 parts by weight of said phenolic substance as a yellowing resistance agent, from about 1 to about 20 parts by weight of filler per 1 part by weight of chromogenic dyestuff, and from about 10 to about 20 parts by weight of a binder in total solid content.
Claim 7
Dependent Claim
41 words
The heat-sensitive recording sheet according to claim 1, wherein said colorless, or pale colored, fluoran-type, dyestuff is at least one substance selected from the group consisting of 3-diethylamino-6-methyl-7-anilinofluoran, 3-(n-ethyl-p-toluidino)-6-methyl-7-anilinofluoran, 3-diethyl-amino-6-methyl-7-(o,p-dimethylanilino)fluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 3-piperidino-6-methyl-7-anilino-fluoran, 3-(N-cyclohexyl-N-methylamino)-6-methyl-7-anilino-fluoran, 3-diethylamino-7-(o-chloroanilino) fluoran, 3-diethylamino-7-(m-trifluoromethylanilino) fluoran, 3-diethylamino-6-methylchlorofluoran 3-diethylamino-6-methylfluoran, and 3-cyclohexylamino-6-chlorofluoran.
Claim 8
Dependent Claim
14 words
The heat-sensitive recording sheet according to claim 1, wherein said chromogenic dyestuff is 3-diethylamino-6-methyl-7-anilinofluoran.
Claim 9
Dependent Claim
24 words
The heat-sensitive recording sheet according to claim 1, wherein said chromogenic dyestuff is 3-pyrrolidino-6-methyl-7-anilinofluoran and said color developing agent is p-hydroxy-benzoic acid benzyl ester.
Claim 10
Dependent Claim
26 words
The heat-sensitive recording sheet according to claim 1, wherein said chromogenic dyestuff is 3-diethylamino-6-methyl-7-(o,p-dimethylanilino) fluoran and said color developing agent is p-hydroxy benzoic acid butyl ester.
Claim 11
Dependent Claim
15 words
The heat-sensitive recording sheet according to claim 1, wherein said color-forming layer includes a binder.
Claim 12
Dependent Claim
17 words
The heat-sensitive recording sheet according to claim 10 wherein said binder is polyvinyl alcohol or hydroxy-ethyl cellulose.
Claim 13
Dependent Claim
26 words
The heat-sensitive recording sheet according to claim 1, wherein said color-forming layer contains a phenol as the color developing agent in addition to p-hydroxybenzoic acid ester.
Claim 14
Dependent Claim
33 words
The heat-sensitive recording sheet according to claim 12, wherein said phenol as the color developing agent is at least one substance selected from the group consisting of p-tertiary-butylphenol, p-phenylphenol, and Novolak phenolic resin.
Claim 15
Dependent Claim
34 words
The heat-sensitive recording sheet according to claim 12, wherein said chromogenic dyestuff is 3-(N-cyclohexyl-N-methylamino)-6-methyl-7-anilinofluoran, said color developing agent is p-hydroxybenzoic acid benzyl ester and p-phenylphenol, and said phenolic substance which resists yellowing is 4,4'-butylidene-bis-(3-methyl-6-tertiary-butylphenol).
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) | 1986-08-15 | 1987-02-14 | 1987-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-08-15 | 1991-02-14 | 1991-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-08-15 | 1995-02-14 | 1995-08-16 | $7700.00 | Window Closed / Lapsed |