JP3063078B2 - Thermal recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosensitive recording medium having excellent image storability.

[0002]

2. Description of the Related Art In general, a thermosensitive recording medium is prepared by grinding and dispersing a colorless or pale-colored basic colorless dye and a developer such as a phenolic compound into fine particles, and then mixing the two. A coating obtained by adding a binder, a filler, a sensitivity enhancer, a lubricant and other auxiliaries to a support such as paper, synthetic paper, film, plastic, etc.
A color image is formed by an instantaneous chemical reaction caused by heating of a mulled head, a hot stamp, a hot pen, a laser beam or the like, thereby obtaining a recorded image.

[0003] The thermal recording medium is a facsimile or a computer.
Terminal printer, automatic ticket vending machine, measurement recorder
In recent years, it has been used for various purposes such as home delivery slips and bar code labels for food. However, in a conventional so-called dye-type thermosensitive recording medium in which a thermosensitive coloring layer containing a basic colorless dye, a color developer and a binder as active ingredients is coated on a support, a color image disappears with time. It was known and had been a problem. This decolorization is accelerated by exposure to light, high-temperature, high-humidity atmosphere, and further progresses significantly due to long standing in water, contact with oil such as salad oil, or plasticizer, and the image becomes unreadable. I will.

[0004] In order to suppress such a decoloring phenomenon, various techniques have been disclosed for heat-sensitive recording materials using a basic colorless dye mainly comprising a colorless or pale-colored lactone ring compound. For example, as disclosed in JP-A-60-78782 and JP-A-59-114096, a phenolic antioxidant is incorporated in a thermosensitive coloring layer.
As disclosed in JP-A-146794, those using a hydrophobic polymer compound emulsion or the like for a protective layer,
As disclosed in Japanese Patent No. 164579, there is known a phenol-based developer in which an epoxy compound is used in combination. However, it is still insufficient for practical use, and a search for a new means for stabilizing an image is required.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to greatly improve the image stability of a heat-sensitive recording medium comprising a basic colorless dye and a phenol-based developer, particularly the stability to a plasticizer. And

[0006]

Means for Solving the Problems The inventors of the present invention have made intensive studies to develop a thermosensitive recording medium having the above-mentioned performance, and as a result, by including a specific stabilizer in the thermosensitive coloring layer, It has been found that the object has been achieved, and the present invention has been completed. That is, the present invention relates to a heat-sensitive recording material provided with a heat-sensitive coloring layer containing a colorless or pale-colored basic dye and an organic developer as main components, wherein the heat-sensitive recording color-forming layer is a compound represented by the following general formula (I) The aminobenzenesulfonamide derivative represented by the formula
And at least one methylolated fatty acid amide represented by the following general formula (II) in an amount of 0.01 to 2 parts with respect to 1 part of the developer. The present invention relates to a thermosensitive recording medium contained therein.

[0007]

Embedded image (Wherein, X represents an oxygen atom or a sulfur atom;
Is an unsubstituted or substituted phenyl group, naphthyl group, aralkyl group, lower alkyl group having 1 to 6 carbon atoms, cycloalkyl group having 3 to 6 carbon atoms, or 2 to 6 carbon atoms.
Represents a lower alkenyl group. Z represents a lower alkyl group having 1 to 6 carbon atoms or an electron-withdrawing group. n represents an integer of 0 to 4, and p represents an integer of 1 to 5. Where n + p ≦ 5
Meet. )

[0008]

Embedded image (In the formula, R ₁ represents an alkyl group having 11 to 21 carbon atoms.)

In the present invention, the general formula (I) is contained in the heat-sensitive coloring layer.
And an aminobenzenesulfonamide derivative represented by the formula: In the general formula (I), X is an oxygen atom or a sulfur atom, and Z may be any substituent that does not hinder the function as a stabilizer. Examples of such a substituent include a methyl group and an ethyl group. Examples thereof include a lower alkyl group having 1 to 6 carbon atoms or an electron-withdrawing group such as a chlorine atom, a nitro group and a methoxy group. R represents a hydrocarbon group, specifically, a phenyl group, an aralkyl group, a lower alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and a lower alkenyl having 2 to 6 carbon atoms. Or a naphthyl group. Further, a substituent which does not inhibit the stabilizing effect can be inserted in R, and the substituent may be a group having 1 carbon atom such as a methyl group or an ethyl group.
1 to 6 carbon atoms such as a lower alkyl group and an isopropenyl group
To 6 lower alkenyl groups or electron-withdrawing groups such as a chlorine atom, a nitro group and a methoxy group. General formula (I)
Specific examples of the compound represented by are shown below (I
-1) to (I-72), but are not limited thereto. Here, (I-10) is preferably used in terms of availability of raw materials and ease of synthesis.

[0010]

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[0011]

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[0012]

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[0013]

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[0014]

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[0015]

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[0016]

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[0017]

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In the present invention, when the amount of the aminobenzenesulfonamide derivative represented by the general formula (I) is less than 0.01 part relative to 1 part of the developer, a sufficient stabilizing effect cannot be expected. If the amount is more than 0.9 part per part, sufficient color density cannot be obtained. Therefore, in order to obtain a well-balanced quality thermal recording medium that satisfies both the stabilizing effect and the color density, the aminobenzenesulfonamide derivative represented by the general formula (I) is added in an amount of 0.1 to 1 part of the developer. 01-0.
It is desirable to use 9 parts.

Furthermore, in the present invention, at least one methylolated fatty acid amide represented by the general formula (II) is contained in the thermosensitive coloring layer together with the compound of the general formula (I).

In the general formula (II), R ₁ represents a hydrocarbon group, specifically, an alkyl group having 11 to 21 carbon atoms. Specific examples of the compound represented by the general formula (II) include (II-1) to (II-4) shown below, but are not limited thereto. Here, (II-3) is preferably used in terms of availability and a stabilizing effect when used in combination with the above (I-10).

[0021]

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In the present invention, the methylolated fatty acid amide represented by the general formula (II) is added in an amount of 0.1 to 1 part of the developer.
If the amount is less than 01 parts, a sufficient stabilizing effect cannot be expected. If the amount is more than 2 parts per 1 part of the developer, sufficient color density cannot be obtained. Therefore, in order to obtain a well-balanced quality thermal recording medium that satisfies both the stability effect and the color density,
It is desirable to use the methylolated fatty acid amide represented by the general formula (II) at a ratio of 0.01 to 2 parts to 1 part of the developer.

In the present invention, the aminobenzenesulfonamide derivative represented by the general formula (I) used as a stabilizer has its own color developing ability, but the organic color developer generally used for a thermosensitive recording medium is used. Inferior to the color developing ability of the agent. However, by using the compound of the general formula (I) at a specific ratio to 1 part of the organic developer,
The compound of the general formula (I) exhibits a function as a stabilizer. The reason for this is not clearly understood,
It is estimated as follows.

In general, a thermosensitive recording medium is composed of a basic colorless dye as an electron donor and an organic acidic substance as an electron acceptor. Electrons are transferred between these basic colorless dyes and the developer by thermal melting, whereby a kind of complex is formed and a color-developed image is obtained. It is considered that the compound of the general formula (I) enhances the chemical bonding force between the basic colorless dye and the developer and stabilizes the recorded image.
On the other hand, the compound of the general formula (II) is considered to enhance the interaction between the above-mentioned complex and the compound of the general formula (I) when eutectically melted with the compound (I). Therefore, in the present invention, a thermosensitive recording medium having high stability can be obtained by using the compounds of the general formulas (I) and (II) in combination.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION The heat-sensitive recording material of the present invention comprises a basic colorless dye, a color developer, at least one aminobenzenesulfonamide derivative represented by the above formula (I) as a stabilizer, and a stabilizer. At least one type of methylolated fatty acid amide represented by the general formula (II) is dispersed together with a binder, and a filler and other additives are added as needed to prepare a thermosensitive coloring layer coating material. On a support and dried.

As the basic colorless dye to be used in the heat-sensitive recording material of the present invention, any of those known in the field of conventional pressure-sensitive or heat-sensitive recording paper can be used, and is not particularly limited. Preference is given to methane compounds, fluoran compounds, fluorene compounds, divinyl compounds and the like. Specific examples of typical basic colorless dyes are shown below. These basic colorless dyes may be used alone or in combination of two or more.

<Triphenylmethane leuco dye> 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide [also known as crystal violet lactone] 3,3-bis (p-dimethylaminophenyl) phthalide Also known as malachite green lactone]

<Fluoran Leuco Dye> 3-Diethylamino-6-methylfluoran 3-Diethylamino-6-methyl-7-anilinofluoran 3-Diethylamino-6-methyl-7- (o, p-dimethylanilino ) Fluoran 3-diethylamino-6-methyl-7-chlorofluoran 3-diethylamino-6-methyl-7- (m-trifluoromethylanilino) fluoran 3-diethylamino-6-methyl-7- (o-chloroanilino) Fluoran 3-diethylamino-6-methyl-7- (p-chloroanilino) fluoran 3-diethylamino-6-methyl-7- (o-fluoroanilino) fluoran 3-diethylamino-6-methyl-7-n-octylanilino Fluoran 3-diethylamino-6-methyl-7-n-octylua Minofluoran 3-diethylamino-6-methyl-7-benzylanilinofluoran 3-diethylamino-6-methyl-7-dibenzylanilinofluoran 3-diethylamino-6-chloro-7-methylfluoran 3-diethylamino-6 -Chloro-7-anilinofluorane 3-diethylamino-6-chloro-7-p-methylanilinofluoran 3-diethylamino-6-ethoxyethyl-7-anilinofluoran 3-diethylamino-7-methylfluoran 3-diethylamino-7- (chloroanilino) fluoran 3-diethylamino-7- (m-trifluoromethylanilino) fluoran 3-diethylamino-7- (o-chloroanilino) fluoran 3-diethylamino-7- (p-chloroanilino) fluoran 3 -Diethylamino-7- ( -Fluoroanilino) fluoran 3-diethylamino-benzo [a] fluoran 3-diethylamino-benzo [c] fluoran 3-dibutylamino-6-methyl-fluoran 3-dibutylamino-6-methyl-7-anilinofluoran 3 -Dibutylamino-6-methyl-7- (o, p-dimethylanilino) fluoran 3-dibutylamino-6-methyl-7- (o-chloroanilino) fluoran 3-dibutylamino-6-methyl-7- (p -Chloroanilino) fluoran 3-dibutylamino-6-methyl-7- (o-fluoroanilino) fluoran 3-dibutylamino-6-methyl-7- (m-trifluoromethylanilino) fluoran 3-dibutylamino-6 -Methyl-chlorofluoran 3-dibutylamino-6-ethoxyethyl- 7-anilinofluoran 3-dibutylamino-6-chloro-7-anilinofluoran 3-dibutylamino-6-methyl-7-p-methylanilinofluoran 3-dibutylamino-7- (o-chloroanilino ) Fluoran 3-dibutylamino-7- (o-fluoroanilino) fluoran 3-n-dipentylamino-6-methyl-7-anilinofluoran 3-n-dipentylamino-6-methyl-7- (p- Chloroanilino) fluoran 3-n-dipentylamino-7- (m-trifluoromethylanilino) fluoran 3-n-dipentylamino-6-chloro-7-anilinofluoran 3-n-dipentylamino-7- (p -Chloroanilino) fluoran 3-pyrrolidino-6-methyl-7-anilinofluoran 3-piperidino-6-methyl 7-anilinofluoran 3- (N- methyl -N- propylamino) -6-methyl-7-anilinofluoran 3- (N- methyl -N- cyclohexylamino) -6-
Methyl-7-anilinofluoran 3- (N-ethyl-N-cyclohexylamino) -6
Methyl-7-anilinofluoran 3- (N-ethyl-N-xylamino) -6-methyl-
7- (p-chloroanilino) fluoran 3- (N-ethyl-p-toluidino) -6-methyl-
7-anilinofluoran 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluoran 3- (N-ethyl-N-isoamylamino) -6-chloro-7-anilino Fluoran 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluoran 3- (N-ethyl-N-isobutylamino) -6-methyl-7-anilinofluoran 3- (N-ethyl-N-ethoxypropylamino) -6
-Methyl-7-anilinofluoran 3-cyclohexylamino-6-chlorofluoran 2- (4-oxahexyl) -3-dimethylamino-6
-Methyl-7-anilinofluoran 2- (4-oxahexyl) -3-diethylamino-6
-Methyl-7-anilinofluoran 2- (4-oxahexyl) -3-dipropylamino-
6-methyl-7-anilinofluoran 2-methyl-6-p- (p-dimethylaminophenyl)
Aminoanilinofluoran 2-methoxy-6-p- (p-dimethylaminophenyl) aminoanilinofluoran 2-chloro-3-methyl-6-p- (p-phenylaminophenyl) aminoanilinofluoran 2 -Chloro-6-p- (p-dimethylaminophenyl)
Aminoanilinofluoran 2-nitro-6-p- (p-diethylaminophenyl)
Aminoanilinofluoran 2-amino-6-p- (p-diethylaminophenyl)
Aminoanilinofluoran 2-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluoran 2-phenyl-6-methyl-6-p- (p-phenylaminophenyl) aminoanilinofluoran 2- Benzyl-6-p- (p-phenylaminophenyl) aminoanilinofluoran 2-hydroxy-6-p- (p-phenylaminophenyl) aminoanilinofluoran 3-methyl-6-p- (p-dimethyl Aminophenyl)
Aminoanilinofluoran 3-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluoran 3-diethylamino-6-p- (p-dibutylaminophenyl) aminoanilinofluoran 2,4-dimethyl- 6-[(4-dimethylamino) anilino] -fluoran

<Fluorene Leuco Dye>3,6,6'-Tris (dimethylamino) spiro [fluorene-9,3'-phthalide] 3,6,6'-Tris (diethylamino) spiro [fluorene-9,3 '-Phthalide]

<Divinyl leuco dye> 3,3-bis- [2- (p-dimethylaminophenyl)
-2- (p-methoxyphenyl) ethenyl] -4,5
6,7-tetrabromophthalide 3,3-bis- [2- (p-dimethylaminophenyl)
-2- (p-methoxyphenyl) ethenyl] -4,5
6,7-tetrachlorophthalide 3,3-bis- [1,1-bis (4-pyrrolidinophenyl) ethylene-2-yl] -4,5,6,7-tetrabromophthalide 3,3- Bis- [1- (4-methoxyphenyl) -1-
(4-pyrrolidinophenyl) ethylene-2-yl]-
4,5,6,7-tetrachlorophthalide

<Others> 3- (4-diethylamino-2-ethoxyphenyl)-
3- (1-ethyl-2-methylindol-3-yl)
-4-azaphthalide 3- (4-diethylamino-2-ethoxyphenyl)-
3- (1-octyl-2-methylindol-3-yl) -4-azaphthalide 3- (4-cyclohexylethylamino-2-methoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) ) -4-Azaphthalide 3,3-bis (1-ethyl-2-methylindole-3
-Yl) phthalide 3,6-bis (diethylamino) fluoran-γ- (3
'-Nitro) anilinolactam 3,6-bis (diethylamino) fluoran-γ- (4
'-Nitro) anilinolactam 1,1-bis- [2', 2 ', 2 ", 2" -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2,
2-dinitrileethane 1,1-bis- [2 ′, 2 ′, 2 ″, 2 ″ -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2-
β-naphthoylethane 1,1-bis- [2 ′, 2 ′, 2 ″, 2 ″ -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2,
2-Diacetylethane bis- [2,2,2 ', 2'-tetrakis- (p-dimethylaminophenyl) -ethenyl] -methylmalonic acid dimethyl ester

In the present invention, the influence on the image stability due to the difference between the basic colorless dyes is not critical, but gives a slight difference. The reason for this is not clear, but it is considered that the image stability is almost dependent on the polarity of the basic colorless dye (which is determined by the state of development of thin layer chromatography). For example, 3-diethylamino-6-methyl-7-anilinofluoran has a relatively high polarity, compared to 3- (N-ethyl-N-isoamylamino)-
The polarity of 6-methyl-7-anilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran and the like is low. The reactivity of these basic colorless dyes with the color developer is determined in the color image, which is considered to contribute to stabilization and affect the solubility with the plasticizer. However, care must be taken when the polarity is high, since the reactivity with the color developer is large, which may cause ground color development. When a basic colorless dye is mixed and used, the plasticizer resistance is improved. Although the reason for this is not clearly understood, it is presumed that the charge transfer complex is a stronger reactant than when a single basic colorless dye is used.

Examples of the organic color developer used in the thermosensitive recording medium of the present invention include bisphenol A described in JP-A-3-207688 and JP-A-5-24366.
4-hydroxybenzoic acid esters, 4-hydroxyphthalic acid diesters, phthalic acid monoesters, bis-
(Hydroxyphenyl) sulfides, 4-hydroxyphenyl aryl sulfones, 4-hydroxyphenyl aryl sulfonates, 1,3-di [2- (hydroxyphenyl) -2-propyl] -benzenes, 4-hydroxybenzoyloxy Benzoic acid esters and bisphenol sulfones are exemplified. Specific examples of typical known color developers are shown below, but the present invention is not particularly limited thereto. These developers may be used alone or in combination of two or more.

<Bisphenol A>4,4'-isopropylidene diphenol (also called bisphenol A) 4,4'-cyclohexylidene diphenol p, p '-(1-methyl-normalhexylidene) diphenol 1, 7-di (hydroxyphenylthio) -3,5-dioxaheptane

<4-Hydroxybenzoates> Benzyl 4-hydroxybenzoate Ethyl 4-hydroxybenzoate Propyl 4-hydroxybenzoate Isopropyl 4-hydroxybenzoate Butyl 4-hydroxybenzoate 4-Isobutyl 4-hydroxybenzoate Methyl benzyl hydroxybenzoate

<Diesters of 4-hydroxyphthalic acid> Dimethyl 4-hydroxyphthalate 4-Diisopropyl 4-hydroxyphthalate 4-Dibenzyl 4-hydroxyphthalate Dihexyl 4-hydroxyphthalate

<Monoesters of Phthalate> Monobenzyl phthalate Monocyclohexyl phthalate Monophenyl phthalate Monomethyl phenyl phthalate Monoethyl phenyl phthalate Monopropyl benzyl phthalate Monohalogen benzyl phthalate Phthalic acid Monoethoxybenzyl ester

<Bis- (hydroxyphenyl) sulfides> Bis- (4-hydroxy-3-tert-butyl-6-
Methylphenyl) sulfide bis- (4-hydroxy-2,5-dimethylphenyl)
Sulfide bis- (4-hydroxy-2-methyl-5-ethylphenyl) sulfide bis- (4-hydroxy-2-methyl-5-isopropylphenyl) sulfide bis- (4-hydroxy-2,3-dimethylphenyl)
Sulfide bis- (4-hydroxy-2,5-dimethylphenyl)
Sulfide bis- (4-hydroxy-2,5-diisopropylphenyl) sulfide bis- (4-hydroxy-2,3,6-trimethylphenyl) sulfide bis- (2,4,5-trihydroxyphenyl) sulfide bis- ( 4-hydroxy-2-cyclohexyl-5-methylphenyl) sulfide bis- (2,3,4-trihydroxyphenyl) sulfide bis- (4,5-dihydroxy-2-tert-butylphenyl) sulfide bis- (4- Hydroxy-2,5-diphenylphenyl) sulfide bis- (4-hydroxy-2-tert-octyl-5)
-Methylphenyl) sulfide

<4-hydroxyphenylarylsulfones>4-hydroxy-4'-isopropoxydiphenylsulfone4-hydroxy-4'-propoxydiphenylsulfone4-hydroxy-4'-n-butyloxydiphenylsulfone 4-hydroxy- 4'-n-propoxydiphenyl sulfone

<4-Hydroxyphenylarylsulfonates> 4-hydroxyphenylbenzenesulfonate 4-hydroxyphenyl-p-tolylsulfonate 4-hydroxyphenylmethylenesulfonate 4-hydroxyphenyl-p-chlorobenzenesulfonate 4- Hydroxyphenyl-p-tert-butylbenzenesulfonate 4-hydroxyphenyl-p-isopropoxybenzenesulfonate 4-hydroxyphenyl-1'-naphthalenesulfonate 4-hydroxyphenyl-2'-naphthalenesulfonate

<1,3-Di [2- (hydroxyphenyl) -2-propyl] benzenes> 1,3-di [2- (4-hydroxyphenyl) -2-propyl] benzene 1,3-di [ 2- (4-hydroxy-3-alkylphenyl) -2-propyl] benzene 1,3-di [2- (2,4-dihydroxyphenyl)-
2-propyl] benzene 1,3-di [2- (2-hydroxy-5-methylphenyl) -2-propyl] benzene

<Resorcinols> 1,3-dihydroxy-6 (α, α-dimethylbenzyl) -benzene <4-hydroxybenzoyloxybenzoate> Benzyl 4-hydroxybenzoyloxybenzoate Methyl 4-hydroxybenzoyloxybenzoate Ethyl 4-hydroxybenzoyloxybenzoate propyl 4-hydroxybenzoyloxybenzoate butyl 4-hydroxybenzoyloxybenzoate isopropyl 4-hydroxybenzoyloxybenzoate tert-butyl 4-hydroxybenzoyloxybenzoate hexyl 4-hydroxybenzoyloxybenzoate Octyl 4-hydroxybenzoyloxybenzoate Nonyl 4-hydroxybenzoyloxybenzoate Cyclohexyl 4-hydroxybenzoyloxybenzoate 4-hydroxy-benzoyloxy benzoate β- phenethyl 4-hydroxy-benzoyloxy benzoate phenyl 4-hydroxy-benzoyloxy benzoate α- naphthyl 4-hydroxy-benzoyloxy benzoate β- naphthyl 4-hydroxy-benzoyloxy benzoate sec- butyl

<Bisphenolsulfones (I)> bis- (3-1-butyl-4-hydroxy-6-methylphenyl) sulfone bis- (3-ethyl-4-hydroxyphenyl) sulfone bis- (3-propyl-) 4-hydroxyphenyl) sulfone bis- (3-methyl-4-hydroxyphenyl) sulfone bis- (2-isopropyl-4-hydroxyphenyl)
Sulfone bis- (2-ethyl-4-hydroxyphenyl) sulfone bis- (3-chloro-4-hydroxyphenyl) sulfone bis- (2,3-dimethyl-4-hydroxyphenyl)
Sulfone bis- (2,5-dimethyl-4-hydroxyphenyl)
Sulfone bis- (3-methoxy-4-hydroxyphenyl) sulfone 4-hydroxyphenyl-2'-ethyl-4'-hydroxyphenylsulfone 4-hydroxyphenyl-2'-isopropyl-4'-
Hydroxyphenylsulfone 4-hydroxyphenyl-3'-isopropyl-4'-
Hydroxyphenylsulfone 4-hydroxyphenyl-3'-secbutyl-4'-
Hydroxyphenylsulfone 3-chloro-4-hydroxyphenyl-3'-isopropyl-4'-hydroxyphenylsulfone 2-hydroxy-5-t-butylphenyl-4'-hydroxyphenylsulfone 2-hydroxy-5-t-aminophenyl -4'-hydroxyphenylsulfone 2-hydroxy-5-t-isopropylphenyl-4 '
-Hydroxyphenylsulfone 2-hydroxy-5-t-octylphenyl-4'-hydroxyphenylsulfone 2-hydroxy-5-t-butylphenyl-3'-chloro-4'-hydroxyphenylsulfone 2-hydroxy-5-t -Butylphenyl-3'-methyl-4'-hydroxyphenylsulfone 2-hydroxy-5-t-butylphenyl-3'-isopropyl-4'-hydroxyphenylsulfone 2-hydroxy-5-t-butylphenyl-3 '-Chloro-4'-hydroxyphenylsulfone2-hydroxy-5-tert-butylphenyl-3'-methyl-4'-hydroxyphenylsulfone2-hydroxy-5-tert-butylphenyl-3'-isopropyl-4'- Hydroxyphenyl sulfone 2-hydroxy-5-t-butyl Eniru 2'-methyl-4'-hydroxyphenyl sulfone

<Bisphenolsulfones (II)>4,4'-sulfonyldiphenol2,4'-sulfonyldiphenol3,3'-dichloro-4,4'-sulfonyldiphenol3,3'-dibromo-4 , 4'-Sulfonyldiphenol 3,3 ', 5,5'-Tetrabromo-4,4'-sulfonyldiphenol 3,3'-Diamino-4,4'-sulfonyldiphenol

<Others> p-tert-butylphenol 2,4-dihydroxybenzophenone novolak type phenol resin 4-hydroxyacetophenone p-phenylphenol benzyl-4-hydroxyphenylacetate p-benzylphenol

In the present invention, a developer having a plurality of phenolic hydroxyl groups may have higher ground color stability because the ground color may be contaminated (ground color development) by aqueous coating or moisture in the air. When required, a monophenol-based developer is preferably used. In particular, the monophenol-based sulfone developer represented by the above-mentioned 4-hydroxyphenylaryl sulfones has a sulfonyl group in the structure, and a strong electron accepting portion is formed by the electron withdrawing action of the sulfonyl group. In addition, it is desirable to obtain a heat-sensitive recording material having high reactivity with a basic colorless dye and exhibiting high color developing properties and also having excellent ground color stability.

In the present invention, conventionally known sensitizers can be used as long as the desired effects on the above objects are not impaired. Such sensitizers include montanic acid wax, polyethylene wax, 1,2-di- (3-methylphenoxy) ethane, p-benzylbiphenyl, β
-Benzyloxynaphthalene, 4-biphenyl-p-tolyl ether, m-terphenyl, 1,2-diphenoxyethane, dibenzyl oxalate, di (oxachloro) benzyl, oxalate di (p-methylbenzyl) , Dibenzyl terephthalate, benzyl p-benzyloxybenzoate, di-p-tolyl carbonate, phenyl-α-
Naphthyl carbonate, 1,4-diethoxynaphthalene, 1-hydroxy-2-naphthoic acid phenyl ester, o-xylerin-bis- (phenyl ether), 4
Examples thereof include-(m-methylphenoxymethyl) biphenyl, but are not particularly limited thereto. These sensitizers may be used alone or in combination of two or more.

As the binder used in the present invention, completely saponified polyvinyl alcohol having a degree of polymerization of 200 to 1900, partially saponified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, amide-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, butyral-modified polyvinyl alcohol Modified polyvinyl alcohol such as alcohol, hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, cellulose derivatives such as acetyl cellulose, styrene-maleic anhydride copolymer, styrene-butadiene copolymer, polyvinyl chloride, polyvinyl acetate, polyacrylamide , Polyacrylate, polyvinyl butyral, polystyrene and copolymers thereof, polyamide resin, silicone Butter, petroleum resins, terpene resins, ketone resins, and coumarone resins. These polymeric substances include water, alcohol, ketones, esters,
In addition to being used by dissolving in a solvent such as a hydrocarbon, it can be used in a state of being emulsified or dispersed in water or another medium in the form of a paste, and used in combination depending on required quality.

In the present invention, metal salts of p-nitrobenzoic acid (Ca, Zn), which are known stabilizers exhibiting an oil resistance effect of a recorded image and the like, as long as the desired effects on the above-mentioned objects are not impaired, It is also possible to add a metal salt of monobenzyl phthalate (Ca, Zn) or a diphenylsulfone derivative.

The filler which can be used in the present invention includes silica, calcium carbonate, kaolin, calcined kaolin, diatomaceous earth, talc, titanium oxide, zinc oxide, aluminum hydroxide, polystyrene resin, urea-formalin resin, styrene- Examples thereof include methacrylic acid copolymers, styrene-butadiene copolymers, and inorganic or organic fillers such as hollow plastic pigments.

In addition, release agents such as fatty acid metal salts, lubricants such as waxes, ultraviolet absorbers such as benzophenone and triazole, water resistance agents such as glyoxal, dispersants, defoamers, antioxidants, fluorescent Dyes and the like can be used.

As the support, paper, synthetic paper, plastic film, non-woven fabric, metal foil and the like can be used, and a composite sheet combining these may be used.

The amounts of the developer and the basic colorless dye used in the heat-sensitive recording medium of the present invention, and the types and amounts of other various components are determined according to the required performance and recording suitability, and are not particularly limited. However, usually, 0.1 to 2 parts of a dye and 0.5 to 4 parts of a filler are used for 1 part of an organic color developer, and a suitable amount of a binder is 5 to 25% of the total solid content. Further, the compound of the general formula (I) of the present invention is used in an amount of 0.1 to 1 part of the developer.
The compound of the formula (II) is used in an amount of 0.01 to 2 parts per 1 part of the developer.

These developers, dyes, and materials to be added as necessary are pulverized by a pulverizer such as a ball mill, an attritor, a sand grinder or an appropriate emulsifier to a particle diameter of several microns or less, and the binder and Various coating materials are added according to the purpose to form a coating liquid. Examples of the coating method include hand coating, size press coater method, roll coater method, air knife coater method, blend coater method, flow coater method, comma direct method, gravure direct method, gravure reverse method, reverse roll coater method and the like. . After spraying, spraying or dipping, drying may be performed.

Further, for the purpose of improving the storage stability, an overcoat layer of a polymer substance or the like can be provided on the thermosensitive coloring layer. Further, for the purpose of improving the storage stability and sensitivity, an undercoat layer containing an organic filler or an inorganic filler can be provided between the color-forming layer and the support.

[0056]

【Example】

<Manufacture of thermosensitive recording medium> The thermosensitive recording medium of the present invention will be described below by way of examples. In the description, parts and% represent parts by weight and% by weight, respectively, unless otherwise specified.

Example 1 In Example 1, the heat-sensitive recording material of the present invention was prepared by adding 4-hydroxy-4'-isopropoxydiphenyl sulfone (D-8) as a developer and 3-(-) as a basic colorless dye. N-ethyl-N-isoamylamino) -6
This is an example using -methyl-7-anilinofluoran (S-205) and compounds (I-10) and (II-3) as stabilizers. Developer dispersion (solution A), basic colorless dye dispersion (solution B) and sensitizer dispersion (solution C) having the following composition
Are each separately subjected to an average particle size of 1 with a sand grinder.
Wet grinding was performed to a micron. Solution A (Developer dispersion) 4-Hydroxy-4'-isopropoxydiphenyl sulfone (D-8) 6.0 parts 10% aqueous polyvinyl alcohol solution 18.8 parts Water 11.2 parts Solution B (Dye dispersion Liquid) 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluoran (S-205) 2.0 parts 10% aqueous polyvinyl alcohol solution 4.6 parts Water 2.6 parts C liquid (Stabilizer dispersion liquid) Compound (I-10) 4.0 parts 10% aqueous polyvinyl alcohol solution 18.8 parts Water 11.2 parts Liquid D (stabilizer dispersion liquid) Compound (II-3) 4.0 parts 10% aqueous polyvinyl alcohol solution 18.8 parts Water 11.2 parts Next, a dispersion was mixed and stirred at the following ratio to prepare a coating solution. Solution A (developer [D-8] dispersion) 36.0 parts Solution B (dye [S-205] dispersion) 9.2 parts Solution C (stabilizer [compound (I-10)] dispersion) 34.0 parts D solution (stabilizer [compound (II-3)] dispersion) 34.0 parts kaolin clay (50% dispersion) 12.0 parts 50 g / m ² of each of the above coating solutions on one side of a base paper After drying, the sheet was treated with a super calender so that the smoothness was 500 to 600 seconds, and a coating amount of 6.0 g / m ² was obtained. .

Example 2 A thermosensitive recording paper was prepared in the same manner as in Example 1. However, in preparing the solution A, 4-hydroxy-4'-isopropoxydiphenyl sulfone (D
Instead of -8), 4,4'-isopropylidene diphenol (bisphenol A, abbreviated as BPA in the table) was used.

Example 3 A thermosensitive recording paper was prepared in the same manner as in Example 1. However, 4,4'-isopropylidene diphenol (bisphenol A) and 4
-Hydroxy-4'-isopropoxydiphenyl sulfone (D-8) was used. In addition, each dispersion liquid was mixed and stirred as described below to prepare a coating liquid. Liquid A (developer [bisphenol A] dispersion) 18.0 parts Liquid A (developer [D-8] dispersion) 18.0 parts Liquid B (dye [S-205] dispersion) 9 .2 parts liquid C (stabilizer [compound (I-10)] dispersion) 34.0 parts liquid D (stabilizer [compound (II-3)] dispersion) 34.0 parts kaolin clay (50% dispersion) 12.0 copies

Examples 4 to 7 Thermal recording paper was prepared in the same manner as in Example 1. However, when preparing solution B,
(N-ethyl-N-isoamylamino) -6-methyl-
Instead of 7-anilinofluoran (S-205), 3-
Dibutylamino-6-methyl-7-anilinofluoran (ODB-2; Example 4), 3-diethylamino-6
Methyl-7-anilinofluoran (ODB; Example 5), 3-pyrrolidino-6-methyl-7-anilinofluoran (PSD-170; Example 6) and 3,3-bis (p-dimethylamino) Phenyl) -6-dimethylaminophthalide (CVL; Example 7) was used.

Example 8 A thermosensitive recording paper was prepared in the same manner as in Example 1. However, as dyes, 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluoran (S-205) and 3-dibutylamino-6
-Methyl-7-anilinofluoran (ODB-2) 2
The type was used. In addition, each dispersion liquid was mixed and stirred as described below to prepare a coating liquid. Liquid A (developer [D-8] dispersion) 36.0 parts Liquid B (dye [S-205] dispersion) 4.6 parts Liquid B (dye [ODB-2] dispersion) 4.6 parts Liquid C (Stabilizer [Compound (I-10)] dispersion) 34.0 parts Liquid D (Stabilizer [Compound (II-3)] dispersion) 34.0 parts Kaolin Kure (50% dispersion) 12. 0 copies

[Examples 9 to 12] In the same manner as in Example 8, thermosensitive recording paper was prepared. However, in preparing the solution C, the compounds (I-1) and (I-1) were used instead of the compound (I-10).
3), (I-19) and (I-26) were used.

Example 13 A thermosensitive recording paper was prepared in the same manner as in Example 8. However, two kinds of the compound (I-10) and the compound (I-1) were used as the stabilizer in the solution C. In addition, each dispersion liquid was mixed and stirred as described below to prepare a coating liquid. Solution A (Developer [D-8] dispersion) 36.0 parts Solution B (Dye [S-205] dispersion) 9.2 parts Solution C (Stabilizer [Compound (I-1)] dispersion) 17.0 parts Liquid C (Stabilizer [Compound (I-10)] dispersion) 17.0 parts Liquid D (Stabilizer [Compound (II-3)] dispersion) 34.0 parts Kaolin Kure (50% dispersion Liquid) 12.0 parts

Example 14 A thermosensitive recording paper was prepared in the same manner as in Example 8. However, in preparing the solution D, (II-4) was used instead of the compound (II-3).

Example 15 A thermosensitive recording paper was prepared in the same manner as in Example 8. However, compounds (II-3) and (III-3) were used as stabilizers in solution D. In addition, each dispersion liquid was mixed and stirred as described below to prepare a coating liquid. Solution A (developer [D-8] dispersion) 36.0 parts Solution B (dye [S-205] dispersion) 9.2 parts Solution C (stabilizer [compound (I-10)] dispersion) 34.0 parts D liquid (stabilizer [compound (II-3)] dispersion) 17.0 parts D liquid (stabilizer [compound (II-4)] dispersion 17.0 parts kaolin clay (50% dispersion) Liquid) 12.0 parts

Comparative Example 1 A thermosensitive recording paper was prepared in the same manner as in Example 1. However, the liquid C and the liquid D were not mixed in the formation of the coloring layer.

Comparative Example 2 A thermosensitive recording paper was prepared in the same manner as in Example 8. However, the liquid C and the liquid D were not mixed in the formation of the coloring layer.

Comparative Example 3 A thermosensitive recording paper was prepared in the same manner as in Example 8. However, the liquid D was not mixed in the formation of the coloring layer.

Comparative Example 4 A heat-sensitive recording paper was prepared in the same manner as in Example 8. However, the liquid C was not mixed in the formation of the coloring layer.

Comparative Example 5 A thermosensitive recording paper was prepared in the same manner as in Example 15. However, the liquid C was not mixed in the formation of the coloring layer.

Comparative Example 6 A thermosensitive recording paper was prepared in the same manner as in Example 8. However, the liquid C was adjusted as described below in the formation of the coloring layer. C 'liquid (Stabilizer dispersion liquid) Compound (I-10) 0.030 parts 10% aqueous solution of polyvinyl alcohol 0.141 parts Water 0.084 parts Then, the dispersion liquid is mixed and stirred at the following ratio to prepare a coating liquid. did. Liquid A (developer [D-8] dispersion) 36.0 parts Liquid B (dye [S-205] dispersion) 4.6 parts Liquid B (dye [ODB-2] dispersion) 4.6 parts Liquid C ′ (Stabilizer [Compound (I-10)] dispersion) 0.255 parts Liquid D (Stabilizer [Compound (II-3)] dispersion) 34.0 parts Kaolin clay (50% dispersion) 12 .0 copies

Comparative Example 7 A thermosensitive recording paper was prepared in the same manner as in Example 8. However, in the formation of the coloring layer, the D solution was adjusted as follows. D 'liquid (Stabilizer dispersion liquid) Compound (II-3) 0.030 parts 10% aqueous polyvinyl alcohol solution 0.141 parts Water 0.084 parts Then, the dispersion liquid is mixed and stirred at the following ratio to prepare a coating liquid. did. Liquid A (developer [D-8] dispersion) 36.0 parts Liquid B (dye [S-205] dispersion) 4.6 parts Liquid B (dye [ODB-2] dispersion) 4.6 parts Solution C (Stabilizer [Compound (I-10)] dispersion) 34.0 parts D 'Solution (Stabilizer [Compound (II-3)] dispersion) 0.255 parts Kaolin clay (50% dispersion) 12 .0 copies

Comparative Example 8 A thermosensitive recording paper was prepared in the same manner as in Example 8. However, the liquid C was adjusted as described below in the formation of the coloring layer. Liquid C (Stabilizer dispersion liquid) Compound (I-10) 9.0 parts 10% aqueous polyvinyl alcohol solution 42.3 parts Water 25.2 parts Then, the dispersion liquid was mixed and stirred at the following ratio to prepare a coating liquid. . Liquid A (developer [D-8] dispersion) 36.0 parts Liquid B (dye [S-205] dispersion) 4.6 parts Liquid B (dye [ODB-2] dispersion) 4.6 parts Liquid C (Stabilizer [Compound (I-10)] dispersion) 76.5 parts Liquid D (Stabilizer [Compound (II-3)] dispersion) 34.0 parts Kaolin clay (50% dispersion) 0 copies

Comparative Example 9 A heat-sensitive recording paper was prepared in the same manner as in Example 8. However, in the formation of the coloring layer, the D solution was adjusted as follows. Liquid D (Stabilizer dispersion liquid) Compound (II-3) 18.0 parts 10% aqueous polyvinyl alcohol solution 84.6 parts Water 50.4 parts Next, the dispersion liquid was mixed and stirred at the following ratio to prepare a coating liquid. . Liquid A (developer [D-8] dispersion) 36.0 parts Liquid B (dye [S-205] dispersion) 4.6 parts Liquid B (dye [ODB-2] dispersion) 4.6 parts Liquid C (stabilizer [compound (I-10)] dispersion) 34.0 parts Liquid D (stabilizer [compound (II-3)] dispersion) 153.0 parts Kaolin clay (50% dispersion) 12. 0 copies

<Evaluation of thermal recording medium> The thermal recording medium thus prepared was subjected to an applied energy of 0 using TH-PMD (a thermal recording paper printing tester manufactured by Okura Electric Co., Ltd., equipped with a thermal head manufactured by Kyocera Corporation). Printed at .41 mj / dot.
The image recording density of the recorded sample was measured with a Macbeth densitometer (RD-914, using an Amber filter).
The concentration was untreated. Then, a vinyl wrap (Mitsui Toatsu High Wrap KMA) is wrapped around the paper tube in a single layer, the thermosensitive recording medium recorded thereon is pasted thereon, and the vinyl wrap is further wrapped in a triple layer at 40 ° C.4. After standing for a period of time, the Macbeth density of the image area was measured. The ground color density was measured in the same manner. (See Tables 1 and 2)

[0076]

[Table 1]

[0077]

[Table 2]

[0078]

[Table 3]

[0079]

[Table 4]

As is clear from the results of Tables 1 and 2, Examples 1 to 15 of the present invention using the compound represented by the general formula (I) and the compound represented by the general formula (II) Compared to Comparative Examples 1 and 2 in which neither is used, or Comparative Examples 3 to 5 in which only one exists, the image stability with respect to the plasticizer is remarkably higher. Therefore, it can be seen that the compounds represented by the general formulas (I) and (II) do not function as stabilizers when used alone, and show excellent stabilizing effects only when used in combination.

Further, the compound of the general formula (I) was used in an amount of 0.005 part in Comparative Example 6 and in an amount of 1.0 part in Comparative Example 8, based on 1 part of the developer.
The compound of the general formula (II) was contained in a proportion of 0.005 part in Comparative Example 7 and 3 parts in Comparative Example 9, all of which had poor plasticizer resistance. In particular, when either one was too large (Comparative Examples 8 and 9), the recording density was also low. That is, even if the general formula (I) and the general formula (I
Even when the compound of the formula (I) is present at the same time, the compound of the formula (I) defined in the present invention is used in an amount of 0.1 to 1 part of the developer.
Unless the condition that the compound of the general formula (II) is contained in an amount of 0.01 to 2 parts with respect to 1 part of the developer at a ratio of 01 to 0.9 part is satisfied, the intended stability is not obtained. It turns out that it cannot be obtained.

Further, Examples 1 and 2 show that the use of D-8 as a color developer is less likely to cause ground coloration than the case of using BPA, and is superior. Similarly, with respect to the plasticizer resistance, better quality is obtained by using D-8. Regarding the difference in the plasticizer resistance due to the difference in the basic colorless dye, when used alone, Example 6 using PSD-170 was the best, but there was some problem with the ground color. On the other hand, in Example 8 in which S-205 and ODB-2 were used together, both the plasticizer resistance and the ground color were excellent.

[0083]

The heat-sensitive recording material of the present invention has sufficient color development sensitivity and extremely excellent image stability, especially stability against a plasticizer. Therefore, even if it comes into contact with a plasticizer contained in a wrap film, a leather product, or the like, the recorded image is not erased, so that it is highly practical. Further, since the thermosensitive recording medium of the present invention contains the compound represented by the general formula (I) and the compound represented by the general formula (II) in the coloring layer, it requires a protective layer and the like. The plasticizer resistance can be imparted without any problems, and the economy is excellent.

Continued on the front page (72) Inventor Nobuhiro Kudo 1-30-6 Kamiochiai, Shinjuku-ku, Tokyo Nihon Paper Industries Co., Ltd. Product Development Laboratory (72) Inventor Akio Sekine 5-2-11-1 Oji, Kita-ku, Tokyo Japan (56) References JP-A-7-304727 (JP, A) JP-A-7-237357 (JP, A) JP-A-6-210961 (JP, A) JP-A-6-206 179289 (JP, A) JP-A-9-76633 (JP, A) JP-A-9-142524 (JP, A) JP-A-8-295078 (JP, A) JP-A-9-207456 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) B41M 5/28-5/34

Claims (1)

(57) [Claims] 1. A thermosensitive recording medium comprising a support and a thermosensitive coloring layer containing a colorless or pale-colored basic colorless dye and an organic developer as main components, wherein the thermosensitive coloring layer is used as a stabilizer as follows. The aminobenzenesulfonamide derivative represented by the general formula (I) is used in an amount of 0.01 to 0.
9 parts by weight of a methylolated fatty acid amide represented by the following general formula (II) per 1 part of the developer.
A thermosensitive recording medium containing at least one kind in an amount of from 01 to 2 parts. Embedded image (Wherein, X represents an oxygen atom or a sulfur atom;
Is an unsubstituted or substituted phenyl group, naphthyl group, aralkyl group, lower alkyl group having 1 to 6 carbon atoms, cycloalkyl group having 3 to 6 carbon atoms, or 2 to 6 carbon atoms.
Represents a lower alkenyl group. Z represents a lower alkyl group having 1 to 6 carbon atoms or an electron-withdrawing group. n represents an integer of 0 to 4, and p represents an integer of 1 to 5. Where n + p ≦ 5
Meet. ) (In the formula, R ₁ represents an alkyl group having 11 to 21 carbon atoms.)