Record receiver having plural interactive leaves or a colorless – Having a colorless color-former – developer therefor – or... – Having nonchromogenic liquid spread-control or...
Reexamination Certificate
1999-11-01
2001-10-16
Hess, Bruce H. (Department: 1774)
Record receiver having plural interactive leaves or a colorless
Having a colorless color-former, developer therefor, or...
Having nonchromogenic liquid spread-control or...
C503S216000
Reexamination Certificate
active
06303540
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a thermally sensitive recording medium which has good preserving stability of developed color image and good color developing sensitivity.
DESCRIPTION OF THE PRIOR ART
In general, a thermally sensitive recording medium is obtained by following procedure. Namely, a colorless or pale colored basic leuco dye and an organic color developer such as phenolic compound are respectively ground to fine particles and mixed together, a binder, a filler, a sensitizer, a slipping agent and other additives are added, and a coating is obtained. The obtained coating is coated on a substrate such as paper, synthetic paper, film or plastic, thus a thermally sensitive recording medium is obtained. The thermally sensitive recording medium develops color by a instantaneous chemical reaction by beating with a thermal head, a hot stamp, a thermal pen and laser ray, and a recorded image can be obtained. The thermally sensitive recording medium is widely used in a field of a facsimile and a terminal printer of computer, an automatic ticket vending machine and a recorder of measuring equipment. Recently, along with the diversity of recording equipment and the progress of high quality machine, the high speed printing and high speed image recording are becoming possible, and more superior quality is required for the recording sensitivity of thermally recording medium.
As the method to satisfy said requirement, the method to use a dye together with a color developer and a sensitizer. For example, in a case that the color developer is a phenolic compound represented by bis-phenol A, p-benzylbiphenyl (Japanese Patent Laid open Publication 60-82382), p-benzyloxybenzoicbenzoate (Japanese Patent Laid open Publication 57-201691) and benzylnaphtyl ether (Japanese Patent Laid open Publication 58-87094) are used as the desirable sensitizer. When a sensitizer is used, at first, the sensitizer is molten by heating and the molten sensitizer dissolves basic dye and color developer and mixes them by molecular size level, and the color developing reaction is caused. Therefore, the kind of sensitizer, basic dye and color developer to be used must be chosen by a careful consideration.
Especially, in a case that the recording sensitivity is improved by use of a sensitizer, sometimes, it is hard to maintain the preserving stability of recorded image. Concretely, when skin fat is stuck or a plasticizer (DOP, DOA or others) contained in polyvinyl chloride wrapping film is contacted, the defects of remarkable deterioration of image density or the disappearance of recorded image are still serious problems. Further, recently, along with the improvement of an use in the field of label to which a reliance of recorded image is strongly required, the recording materials which displays strong preserving stability to a plasticizer contained in wrapping materials and fats. The thermally sensitive recording medium which uses various additives such as dye, color developer or a preserving stabilizer are disclosed, however, these are not sufficient ones.
THE OBJECT OF THE INVENTION
The object of this invention is to provide a thermally sensitive recording medium which has an excellent stability to plasticizer, and whose recording sensitivity is remarkably improved.
The inventors of this invention have carried out an intensive study to develop the thermally sensitive recording medium which has above mentioned features, and have found that the recording sensitivity can be remarkably improved by an use of diphenylsulfone bridgeable type compound as a color developer together with an aromatic compound possessing aminosulfonyl (—SO
2
NH
2
) group as a sensitizer, and accomplished the present invention.
That is, the present invention is a thermally sensitive recording medium, comprising a thermally sensitive recording layer prepared on a substrate, said thermally sensitive recording layer contains a colorless or pale colored leuco dye and an organic color developer as main components, wherein said thermally sensitive recording layer contains diphenylsulfone bridgeable type compound represented by general formula (1) as an organic color developer and at least one compound represented by general formula (2). And, the sensitivity can be more improved without hurting above mentioned features, by further containing at least one compound represented by general formula (3), general formula (4) or general formula (5).
in this formula, X and Y can be different and indicates a saturated or an unsaturated liner or grafted hydrocarbon group of carbon number 1-12 which can possess an ether bond, or indicate
wherein R indicates a methylene group or an ethylene group, T indicates a hydrogen atom or an alkyl group of carbon number 1-6. R
1
-R
6
independently indicate a halogen atom, an alkyl group of carbon number 1-6, or an alkenyl group. Further, m, n, p, q, r, t indicate an integer of 0-4 and when are bigger than 2, R
1
-R
6
can be different. And a is an integer of 0-10.
in this formula, R
7
represents an alkyl group of carbon number 1-6 or an electron attracting group, u is an integer of 0-2.
R
8
-R
13
, represent a hydrogen atom, an alkyl group, a halogen atom, a nitro group, an alkoxy group, a cyano group or an alyloxy group.
in this formula, V represents an oxygen atom or sulfur atom and R
14
represents an un-substituted or a substituted phenyl group, a naphthyl group, an aralkyl group, a lower alkyl group of carbon number 1-6, a cycloalkyl group of carbon number 3-6 or a lower alkenyl group of carbon number 2-6. W represents a lower alkyl group of carbon number 1-6 or an electron attractive group. y is an integer of 1-4 and x is an integer of 1-5, wherein y+x≦5.
in this formula R
15
indicates an un-substituted or a substituted alkyl group of carbon numder 1-4, an aralkyl group, a phenyl group or a hydrogen atom.
In the present invention, at least one kind of diphenyl sulfone represented by general formula (1) is used as an diphenylsulfone bridgeable type compound as an organic color developer. The diphenylsulfone bridgeable type compound represented by general formula (1) is disclosed in Japanese Patent Laid Open Publication 10-29969.
In general formula (1), the concrete examples of groups represented by X and Y are mentioned as follow. That is, methylene group, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, methylmethylene group, dimethylmethylene group, methylethylene group, methyleneethylene group, ethylethylene group, 1,2-dimethylethylene group, 1-methyltrimethylene group, 1-methyltetramethylene group, 1,3-dimethyltrimethylene group, 1-ethyl-4-methyl-tetramethylene group, vinylene group, propenylene group, 2-butenylene group, ethynylene group, 2-butynylene group, 1-vinyl ethylene group, ethyleneoxyethylene group, tetramethyleneoxytetramethylene group, ethyleneoxyethylene group, ethyleneoxymethyleneoxyethylene group, 1,3-dioxane-5, 5-bismethylene group, 1,2-xylyl group, 1,3-xylyl group, 1,4-xylyl group, 2-hydroxytrimethylene group, 2-hydroxy-2-methyltrimethylene group, 2-hydroxy-2-ethyltrimethylene group, 2-hydroxy-2-propyltrimethylene group, 2-hydroxy-2-isopropyltrimethylene group and 2-hydroxy-2-butyltrimethylene group can be mentioned.
Alkyl or alkenyl group of R
1
-R
6
is an alkyl group of C
1
-C
6
or an alkenyl group of C
1
-C
6
, and as a concrete example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, n-hexyl group, isohexyl group, 1-metylpentyl group, 2-methylpentyl group, vinyl group, allyl group, isopropenyl group, 1-propenyl group, 2-butenyl group, 3-butenyl group, 1,3-butandienyl group and 2-methyl-2-propenyl group can be mentioned. And a halogen atom indicates chloride, bromine, fluorine or iodine.
In this invention, as the diphenylsulfone bridge
Fukuchi Tadakazu
Hamada Kaoru
Kimura Yoshihide
Nagai Tomoaki
Tsuzuki Yuji
Hess Bruce H.
Nippon Paper Industries Co Ltd
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