Patent US4498091A successfully refreshed from Google Patents.
US4498091A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat-sensitive recording sheet
Assignee: Nippon Paper Industries Co Ltd
•
Filing: 1984-03-15
•
Granted: 1985-02-05
•
Expires: 2004-03-15
Abstract
Abstract It has been found that phthalic acid monoester represented by the general formula: ##STR1## in which R is a saturated alkyl group of 4 to 20 carbon atoms where X is an alkyl group, a halogen or an alkoxy group, is applicable as color-developing agent to prepare heat-sensitive recording sheet with excellent results. It is observed that one of the two carboxylic acid groups of which phthalic acid is composed is esterified with the group mentioned in the claim to form water-insoluble, insublimable compound having melting point of 90° to 130° C. wherein the group introduced controls the acidity of the adjacent carboxylic acid group into a condition suitable for stable and concentrated color-development of colorless dye.
Inventors
- 👤 Noboru Yamato
- 👤 Toshimi Satake
- 👤 Toshiaki Minami
- 👤 Fumio Fujimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 22:47
CPC Classifications
B; B41; B41M; B41M5/00; B41M5/26; B41M5/30; B41M5/333; B41M5/3333; B41M5/3335
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
60 words
Heat-sensitive recording sheet having a color-forming layer comprising (1) a colorless or pale colored chromogenic dyestuff and (2) a color developing material which is a phthalic acid monoester of the general formula: ##STR4## in which R is a saturated alkyl group of 4 to 20 carbon atoms, ##STR5## where X is an alkyl group, a halogen or an alkoxy group.
Claim 2
Dependent Claim
60 words
Heat-sensitive recording sheet having a color-forming layer comprising (1) a colorless or pale colored chromogenic dyestuff and (2) a color developing material which is a phthalic acid monoester of the general formula: ##STR4## in which R is a saturated alkyl group of 4 to 20 carbon atoms, ##STR5## where X is an alkyl group, a halogen or an alkoxy group.
Claim 3
Dependent Claim
44 words
Heat-sensitive recording sheet according to claim 1, wherein said phthalic acid monoester is selected from the group consisting of phthalic acid monophenylester, phthalic acid monobenzylester, phthalic acid monocyclohexylester, phthalic acid monomethylphenylester, phthalic acid monoethylphenylester phthalic acid monoalkylbenzylester, phthalic acid monohalogenbenzylester and phthalic and monoalkyoxybenzylester.
Claim 4
Dependent Claim
17 words
Heat-sensitive recording sheet according to claim 2, wherein said phthalic acid monoester is phthalic acid monobenzyl ester.
Claim 5
Dependent Claim
19 words
Heat-sensitive recording sheet according to claim 1, wherein said phthalic acid monoester is used together with organic carboxylic acids.
Claim 6
Dependent Claim
18 words
Heat-sensitive recording sheet according to claim 1, wherein said phthalic acid monoester is used together with phenolic substance.
Claim 7
Dependent Claim
36 words
Heat sensitive recording sheet according to claim 5, wherein said phenolic substance selected from the group consisting of bisphenol A (4,4'-isopropylidene diphenol, p,p'-(1-methyl-normalhexylidene diphenol, p-tertiary butylphenol, p-phenylphenol, p-hydroxybenzoic acid ester, Novolak phenolic resin, 4-hydroxy-1-methylsulfonylbenzene, and 4-hydroxy-1-butyloxysulfonylbenzene.
References Cited (Backward Citations)
US3911171A
Cited
US3965282A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-02-05 | 1988-08-06 | 1989-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-02-05 | 1992-08-06 | 1993-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-02-05 | 1996-08-06 | 1997-02-05 | $7700.00 | Window Closed / Lapsed |