JPH09216461A - Thermosensitive recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To greatly the improve the, image stability of a thermosensitive recording medium or particularly the stability of plasticizer by incorporating specific amount of specific aminobenzenesulfonamide derivative as the stabilizer in the thermal coloring layer of the medium, and incorporating specific amount of specific methylol fatty amide therein. SOLUTION: In the thermosensitive recording medium having a thermal coloring layer containing colorless or pale basic dye and organic developer as main component, aminobenzenesulfonamide derivative represented by a formula I is contained at the ratio of 0.01 to 0.9 part to one part of the developer as the stabilizer in a thermal recording coloring layer. Further, at least one type of methylol fatty amide represented by a formula II is contained at the ratio of 0.01 to 2 part to the one part of developer. In the formula I, X is oxygen atom or sulfur atom, R is phenyl group or naphthyl group, Z is 1-6C lower alkyl group, n is integer of 0 to 4, p is integer of 1 to 5, (n+p<=5), and in the formula II, R1 is 11-21C alkyl group.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material excellent in image storability.

[0002]

2. Description of the Related Art Generally, a heat-sensitive recording material is generally prepared by grinding and dispersing a colorless or light-colored basic colorless dye and a color developing agent such as a phenolic compound into fine particles, and then mixing both. A paint obtained by adding a binder, a filler, a sensitivity improver, a lubricant and other auxiliaries is applied to a support such as paper, synthetic paper, film and plastic.
A recorded image is obtained by developing a color by an instantaneous chemical reaction by heating with a round head, a hot stamp, a hot pen, a laser light or the like.

Thermal recording materials are used for facsimiles and computer.
Terminal printers, vending machines, recorders for measurement
It can be used in a wide range of applications 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 basic colorless dye, a color developer and a binder are applied on the support as a thermosensitive coloring layer, the color-developed image disappears with time. This was known and was a problem. This decolorization is accelerated by exposure to light, high temperature and high humidity atmosphere, and further it is left in water for a long time, and when it is contacted with oil such as salad oil and plasticizer, the image becomes unreadable. I will end up.

In order to suppress such decoloring phenomenon, many techniques have been disclosed for a heat-sensitive recording material using a basic colorless dye mainly composed of a colorless or light-colored lactone ring compound. For example, as shown in JP-A-60-78782 and JP-A-59-114096, a compound containing a phenolic antioxidant in a thermosensitive color developing layer,
No. 146794, a protective polymer layer using a hydrophobic polymer emulsion or the like, as disclosed in JP-A-62-
There is known a compound in which an epoxy compound is used in combination with a phenol-based developer as seen in No. 164579. However, it is still insufficient for practical use, and a search for new means for stabilizing an image is required.

[0005]

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

[0006]

DISCLOSURE OF THE INVENTION As a result of intensive studies conducted by the present inventors in order to develop a thermosensitive recording medium having the above-mentioned properties, as a result of including a specific stabilizer in the thermosensitive coloring layer, The inventors have found that the object is achieved and have completed the present invention. That is, the present invention provides a thermosensitive recording medium provided with a thermosensitive coloring layer containing a colorless or pale-colored basic dye and an organic developer as main components, the thermosensitive recording coloring layer serving as a stabilizer having the following general formula (I ) 0.01% of the aminobenzenesulfonamide derivative represented by
To 0.9 parts by weight and at least one methylated fatty acid amide represented by the following general formula (II) in a ratio of 0.01 to 2 parts with respect to 1 part of the developer. The present invention relates to a thermosensitive recording material.

[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. However, 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 compound represented by the general formula (I) is contained in the thermosensitive coloring layer.
The aminobenzenesulfonamide derivative represented by In the general formula (I), X is an oxygen atom or a sulfur atom, and Z may be a substituent which does not interfere with the function as a stabilizer, and such a substituent may be a methyl group, an ethyl group or the like. Examples thereof include lower alkyl groups having 1 to 6 carbon atoms or electron withdrawing groups such as chlorine atom, nitro group and 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, a lower alkenyl having 2 to 6 carbon atoms. Group or naphthyl group. In addition, R may be substituted with a substituent that does not impair the stabilizing effect, and the substituent has a carbon number of 1 such as methyl and ethyl.
~ 6 lower alkyl group, isopropenyl group, etc., having 1 carbon atom
To 6 lower alkenyl groups or electron withdrawing groups such as chlorine atom, nitro group and methoxy group. General formula (I)
Specific examples of the compound represented by are shown below (I
-1) to (I-72), but the invention is not limited thereto. Here, (I-10) is preferably used from the viewpoint of availability of raw materials and ease of synthesis.

[0010]

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[0011]

[Chemical 6]

[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, the aminobenzenesulfonamide derivative represented by the general formula (I) cannot be expected to have a sufficient stabilizing effect when the amount is less than 0.01 part with respect to 1 part of the developer. If the amount is more than 0.9 parts with respect to 1 part, sufficient color density cannot be obtained. Therefore, in order to obtain a well-balanced quality thermosensitive recording medium that satisfies both the stabilizing effect and the color density, the aminobenzenesulfonamide derivative represented by the general formula (I) can be used in an amount of 0. 01-0.
It is desirable to use 9 parts.

Further, in the present invention, the thermosensitive coloring layer contains at least one methylated fatty acid amide represented by the general formula (II) together with the compound of the general formula (I).

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

[0021]

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In the present invention, the methylolated fatty acid amide represented by the general formula (II) is 0.
If it is less than 01 part, a sufficient stabilizing effect cannot be expected, and if it is more than 2 parts with respect to 1 part of the color developer, sufficient color density cannot be obtained. Therefore, in order to obtain a thermal recording material of a well-balanced quality that satisfies both the stabilizing effect and the color density,
It is desirable to use the methylated fatty acid amide represented by the general formula (II) in a proportion of 0.01 to 2 parts with respect to 1 part of the color developer.

In the present invention, the aminobenzenesulfonamide derivative represented by the general formula (I) used as a stabilizer has a color developing ability per se, but it is generally an organic color developing agent used for a thermosensitive recording medium. It is inferior to the color developing ability of the agent. However, by using the compound of the general formula (I) in a specific ratio to 1 part of the organic developer,
The compounds of general formula (I) act as stabilizers. The reason for this is not clear, but
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 the basic colorless dye and the color developer by heat fusion, whereby a kind of complex is formed and a color image is obtained. Then, the compound of the general formula (I) is considered to enhance the chemical bonding force between the basic colorless dye and the color developer and stabilize the recorded image.
On the other hand, the compound of the general formula (II) is considered to enhance the interaction between the complex and the compound of the general formula (I) when eutectic with the compound (I). Therefore, in the present invention, the thermal recording material having high stability can be obtained by using the compounds of the general formula (I) and the general formula (II) together.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION The heat-sensitive recording material of the present invention comprises a basic colorless dye, a developer, at least one aminobenzenesulfonamide derivative represented by the above general formula (I) as a stabilizer, and a stabilizer. As described above, 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 as necessary are added to prepare a thermosensitive color developing layer coating. Can be obtained by coating on a support and drying.

As the basic colorless dye used in the heat-sensitive recording material of the present invention, all those known in the conventional pressure-sensitive or heat-sensitive recording paper field can be used, and although not particularly limited, triphenyl. Methane compounds, fluorane compounds, fluorene compounds, divinyl compounds and the like are preferable. 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-methylfluorane 3-diethylamino-6-methyl-7-anilinofluorane 3-diethylamino-6-methyl-7- (o, p-dimethylanilino) ) Fluoran 3-diethylamino-6-methyl-7-chlorofluorane 3-diethylamino-6-methyl-7- (m-trifluoromethylanilino) fluorane 3-diethylamino-6-methyl-7- (o-chloroanilino) Fluorane 3-diethylamino-6-methyl-7- (p-chloroanilino) fluorane 3-diethylamino-6-methyl-7- (o-fluoroanilino) fluorane 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) fluorane 3-diethylamino-benzo [a] fluorane 3-diethylamino-benzo [c] fluorane 3-dibutylamino-6-methyl-fluorane 3-dibutylamino-6-methyl-7-anilinofluorane 3 -Dibutylamino-6-methyl-7- (o, p-dimethylanilino) fluorane 3-dibutylamino-6-methyl-7- (o-chloroanilino) fluorane 3-dibutylamino-6-methyl-7- (p -Chloroanilino) fluorane 3-dibutylamino-6-methyl-7- (o-fluoroanilino) fluorane 3-dibutylamino-6-methyl-7- (m-trifluoromethylanilino) fluorane 3-dibutylamino-6 -Methyl-chlorofluoran 3-dibutylamino-6-ethoxyethyl- 7-anilinofluorane 3-dibutylamino-6-chloro-7-anilinofluorane 3-dibutylamino-6-methyl-7-p-methylanilinofluorane 3-dibutylamino-7- (o-chloroanilino ) Fluoran 3-dibutylamino-7- (o-fluoroanilino) fluorane 3-n-dipentylamino-6-methyl-7-anilinofluorane 3-n-dipentylamino-6-methyl-7- (p- Chloroanilino) fluorane 3-n-dipentylamino-7- (m-trifluoromethylanilino) fluorane 3-n-dipentylamino-6-chloro-7-anilinofluorane 3-n-dipentylamino-7- (p -Chloroanilino) fluorane 3-pyrrolidino-6-methyl-7-anilinofluorane 3-piperidino-6-methyi 7-anilinofluoran 3- (N- methyl -N- propylamino) -6-methyl-7-anilinofluoran 3- (N- methyl -N- cyclohexylamino) -6-
Methyl-7-anilinofluorane 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) fluorane-γ- (3
′ -Nitro) anilinolactam 3,6-bis (diethylamino) fluorane-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 of the difference in the basic colorless dyes on the image stability gives a slight difference although it is not decisive. 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 revealed by the development state of thin layer chromatography). For example, 3-diethylamino-6-methyl-7-anilinofluorane has a relatively high polarity compared to 3- (N-ethyl-N-isoamylamino)-.
The polarities of 6-methyl-7-anilinofluorane and 3-dibutylamino-6-methyl-7-anilinofluorane are low. In the color image, the reactivity between the basic colorless dye and the color developer is determined, which is considered to be involved in the stabilization and affect the solubility with the plasticizer. However, when the polarity is high, it is necessary to be careful because the reactivity with the color developer is large and it may cause the background color to develop. Further, when a basic colorless dye is mixed and used, the plasticizer resistance is improved. The reason for this is not clear, but it is presumed that the charge transfer complex is a strong reactant as compared with the case where a single basic colorless dye is used.

Examples of the organic developer used in the heat-sensitive recording material of the present invention include bisphenol A compounds described in JP-A-3-207688, JP-A-5-24366, and the like.
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 Examples thereof include benzoic acid esters and bisphenol sulfones. Specific examples of typical known color developing agents are shown below, but the invention is not particularly limited thereto. Further, these color developing agents may be used alone or in combination of two or more kinds.

<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-hydroxybenzoyloxybenzoic acid ester> benzyl 4-hydroxybenzoyloxybenzoate 4-hydroxybenzoyloxymethyl benzoate Ethyl 4-hydroxybenzoyloxybenzoate Propyl 4-hydroxybenzoyloxybenzoate Butyl 4-hydroxybenzoyloxybenzoate Isopropyl 4-hydroxybenzoyloxy 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

<Bisphenol sulfone (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 novolac type phenol resin 4-hydroxyacetophenone p-phenylphenol benzyl-4-hydroxyphenylacetate p-benzylphenol

In the present invention, since the developer having a plurality of phenolic hydroxyl groups may cause contamination of the ground color (ground color development) due to water-based coating or moisture in the air, higher ground color stability can be obtained. When required, a monophenol type developer is preferably used. In particular, the monophenol-based sulfone color developers represented by the above-mentioned 4-hydroxyphenylaryl sulfones have a sulfonyl group in the structure, and a strong electron acceptor can be formed by the electron withdrawing action of this sulfonyl group. It is desirable to obtain a thermosensitive recording medium which exhibits strong reactivity with a basic colorless dye and exhibits high color development and also has excellent ground color stability.

In the present invention, conventionally known sensitizers can be used as long as the desired effects for the above problems 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 (p-chlorobenzyl) oxalate, di (p-methylbenzyl oxalate) , Dibenzyl terephthalate, benzyl p-benzyloxybenzoate, di-p-tolyl carbonate, phenyl-α-
Naphthyl carbonate, 1,4-diethoxynaphthalene, 1-hydroxy-2-naphthoic acid phenyl ester, o-xylelin-bis- (phenyl ether), 4
Examples thereof include-(m-methylphenoxymethyl) biphenyl, but the present invention is not limited thereto. You may use these sensitizers individually or in mixture of 2 or more types.

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. Modified polyvinyl alcohol such as alcohol, cellulose derivative such as hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, acetyl cellulose, styrene-maleic anhydride copolymer, styrene-butadiene copolymer, polyvinyl chloride, polyvinyl acetate, polyacrylamide , Polyacrylic acid ester, polyvinyl butyral, polystyrene and their copolymers, 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 being dissolved in a solvent such as a hydrocarbon, it may be used in a state of being emulsified in water or another medium or dispersed in a paste form, and may be used together depending on the required quality.

Further, in the present invention, p-nitrobenzoic acid metal salt (Ca, Zn), which is a known stabilizer showing an oil resistance effect of a recorded image, etc., within a range that does not impair the desired effect on the above problems, It is also possible to add phthalic acid monobenzyl ester metal salts (Ca, Zn) or diphenyl sulfone derivatives.

As the filler which can be used in the present invention, 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 to the above, release agents such as fatty acid metal salts, lubricants such as waxes, benzophenone-based and triazole-based UV absorbers, water resistance agents such as glyoxal, dispersants, defoamers, antioxidants, and fluorescent agents. A dye or the like can be used.

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

The amount of the color developer and the basic colorless dye used in the heat-sensitive recording material 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 the dye and 0.5 to 4 parts of the filler are used with respect to 1 part of the organic developer, and 5 to 25% of the total solid content of the binder is suitable. In addition, the compound of the general formula (I) of the present invention is 0.
01 to 0.9 part is used, and the compound of the general formula (II) is used in 0.01 to 2 parts per 1 part of the color developer.

These developers, dyes and materials to be added as required are atomized to a particle size of several microns or less by a pulverizer such as a ball mill, attritor or sand grinder or an appropriate emulsifying device, and a binder and Various kinds of additive materials are added according to the purpose to prepare 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, etc. . Moreover, you may dry after spraying, spraying, or immersion.

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

[0056]

【Example】

<Production of Thermal Recording Material> The thermal recording material of the present invention will be described below with reference to examples. The parts and% in the description 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 color developer and 3- () as a basic colorless dye. N-ethyl-N-isoamylamino) -6
In this example, -methyl-7-anilinofluorane (S-205) and compounds (I-10) and (II-3) were used as stabilizers. Dispersion liquid of developer (A liquid), basic colorless dye dispersion liquid (B liquid) and sensitizer dispersion liquid (C liquid) having the following composition
, And separately using a sand grinder to obtain an average particle size of 1
Wet grinding was performed to a micron. A liquid (developer dispersion liquid) 4-hydroxy-4'-isopropoxydiphenyl sulfone (D-8) 6.0 parts 10% polyvinyl alcohol aqueous solution 18.8 parts water 11.2 parts B liquid (dye dispersion) Liquid) 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluorane (S-205) 2.0 parts 10% polyvinyl alcohol aqueous solution 4.6 parts water 2.6 parts C liquid (Stabilizer dispersion liquid) Compound (I-10) 4.0 parts 10% polyvinyl alcohol aqueous solution 18.8 parts Water 11.2 parts Liquid D (stabilizer dispersion liquid) Compound (II-3) 4.0 parts 10% polyvinyl alcohol aqueous solution 18.8 parts Water 11.2 parts Next, the dispersion liquids were mixed and stirred at the following ratios to prepare coating liquids. Liquid A (developer [D-8] dispersion liquid) 36.0 parts Liquid B (dye [S-205] dispersion liquid) 9.2 parts Liquid C (stabilizer [compound (I-10)] dispersion liquid) 34.0 parts D liquid (stabilizer [compound (II-3)] dispersion) 34.0 parts Kaolin clay (50% dispersion) 12.0 parts Each of the above coating liquids on one side of 50 g / m ² base paper After coating, the sheet was dried and treated with a super calender to obtain a smoothness of 500 to 600 seconds, and a coating amount of 6.0 g / m ² was obtained. .

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

[Example 3] Thermal recording paper was prepared in the same manner as in Example 1. However, 4,4'-isopropylidenediphenol (bisphenol A) and 4
Two types of -hydroxy-4'-isopropoxydiphenyl sulfone (D-8) were used. Each dispersion was mixed and stirred as described below to prepare a coating liquid. Liquid A (developing agent [bisphenol A] dispersion liquid) 18.0 parts Liquid A (developing material [D-8] dispersion liquid) 18.0 parts Liquid B (dye [S-205] dispersion liquid) 9 .2 parts C liquid (stabilizer [compound (I-10)] dispersion liquid) 34.0 parts D liquid (stabilizer [compound (II-3)] dispersion liquid) 34.0 parts Kaolin clay (50% dispersion liquid) ) 12.0 copies

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

Example 8 A thermal recording paper was prepared in the same manner as in Example 1. However, as the dye, 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluorane (S-205) and 3-dibutylamino-6 are used.
-Methyl-7-anilinofluorane (ODB-2) -2
The type was used. Each dispersion was mixed and stirred as described below to prepare a coating liquid. Liquid A (developer [D-8] dispersion liquid) 36.0 parts Liquid B (dye [S-205] dispersion liquid) 4.6 parts Liquid B (dye [ODB-2] dispersion liquid) 4.6 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. Copy 0

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

[Example 13] A thermal recording paper was prepared in the same manner as in Example 8. However, two kinds of compounds (I-10) and (I-1) were used as the stabilizer in the liquid C. Each dispersion was mixed and stirred as described below to prepare a coating liquid. Liquid A (developer [D-8] dispersion liquid) 36.0 parts Liquid B (dye [S-205] dispersion liquid) 9.2 parts Liquid C (stabilizer [compound (I-1)] dispersion liquid) 17.0 parts C liquid (stabilizer [compound (I-10)] dispersion liquid) 17.0 parts D liquid (stabilizer [compound (II-3)] dispersion liquid 34.0 parts Kaolin clay (50% dispersion) Liquid) 12.0 parts

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

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

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

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

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

[Comparative Example 4] A thermosensitive recording paper was prepared in the same manner as in Example 8. However, C liquid was not mixed in the formation of the color forming layer.

[Comparative Example 5] A thermal recording paper was prepared in the same manner as in Example 15. However, C liquid was not mixed in the formation of the color forming layer.

[Comparative Example 6] A thermosensitive recording paper was prepared in the same manner as in Example 8. However, in the formation of the color forming layer, the liquid C was adjusted as follows. Liquid C '(stabilizer dispersion liquid) Compound (I-10) 0.030 parts 10% aqueous polyvinyl alcohol solution 0.141 parts water 0.084 parts The dispersion liquids are mixed and stirred at the following ratios to adjust the coating liquids. did. Liquid A (developer [D-8] dispersion liquid) 36.0 parts Liquid B (dye [S-205] dispersion liquid) 4.6 parts Liquid B (dye [ODB-2] dispersion liquid) 4.6 parts C'liquid (stabilizer [compound (I-10)] dispersion) 0.255 parts D liquid (stabilizer [compound (II-3)] dispersion) 34.0 parts Kaolin clay (50% dispersion) 12 .0 copy

[Comparative Example 7] A thermosensitive recording paper was prepared in the same manner as in Example 8. However, in the formation of the color-developing layer, the liquid D was prepared as follows. Liquid D '(stabilizer dispersion) Compound (II-3) 0.030 parts 10% aqueous polyvinyl alcohol solution 0.141 parts water 0.084 parts The dispersions are mixed and stirred at the following ratios to prepare coating solutions. did. Liquid A (developer [D-8] dispersion liquid) 36.0 parts Liquid B (dye [S-205] dispersion liquid) 4.6 parts Liquid B (dye [ODB-2] dispersion liquid) 4.6 parts Solution C (stabilizer [compound (I-10)] dispersion) 34.0 parts Solution D '(stabilizer [compound (II-3)] dispersion) 0.255 parts Kaolin clay (50% dispersion) 12 .0 copy

[Comparative Example 8] A thermosensitive recording paper was prepared in the same manner as in Example 8. However, in the formation of the color forming layer, the liquid C was adjusted as follows. Liquid C (stabilizer dispersion liquid) Compound (I-10) 9.0 parts 10% aqueous polyvinyl alcohol solution 42.3 parts Water 25.2 parts The dispersion liquids were mixed and stirred at the following ratios to prepare coating liquids. . Liquid A (developer [D-8] dispersion liquid) 36.0 parts Liquid B (dye [S-205] dispersion liquid) 4.6 parts Liquid B (dye [ODB-2] dispersion liquid) 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) 12. Copy 0

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

<Evaluation of Thermal Recording Material> The thermal recording material thus prepared was subjected to an applied energy of 0 using a TH-PMD (a thermal recording paper printing tester, Kyocera, equipped with a thermal head) manufactured by Okura Electric Co., Ltd. It was printed at 0.41 mj / dot.
The image recording density of this recorded sample was measured with a Macbeth densitometer (RD-914, using an amber filter),
Untreated concentration. Then, vinyl chloride wrap (High lap KMA manufactured by Mitsui Toatsu Co., Ltd.) was wrapped around the paper tube in a single layer, the heat-sensitive recording material recorded thereon was attached, and further, vinyl chloride wrap was wrapped in a triple layer at 40 ° C. After leaving for a time, the Macbeth density in the image area was measured. The background color density was also measured in the same manner. (See Tables 1 and 2)

[0076]

[Table 1]

[0077]

[Table 2]

[0078]

[Table 3]

[0079]

[Table 4]

As is apparent 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 with Comparative Examples 1 and 2 in which neither of them is used, or Comparative Examples 3 to 5 in which only one is present, the image stability with respect to the plasticizer is remarkably high. Therefore, it can be seen that the compounds represented by the general formula (I) and the general formula (II) do not function as stabilizers when used alone, and show an excellent stabilizing effect only when used in combination.

In addition, for 1 part of the color developer, 0.005 parts of the compound of the general formula (I) was used for Comparative Example 6, and 1.5 parts for Comparative Example 8.
The content of the compound of the general formula (II) was 0.005 parts in Comparative Example 7 and 3 parts in Comparative Example 9, but the plasticizer resistance was poor. In particular, the recording density was low when either one was too large (Comparative Examples 8 and 9). 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 general formula (I) defined in the present invention is 0.
If the condition that the compound of the general formula (II) is contained in a proportion of 0.01 to 2 parts per 1 part of the developer at a proportion of 01 to 0.9 parts is satisfied, the desired stability is obtained. You can see that you cannot get it.

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

[0083]

The heat-sensitive recording material of the present invention has a sufficient color-forming sensitivity and is extremely excellent in image stability, particularly in stability to a plasticizer. Therefore, the recorded image will not be erased even when it comes into contact with the plasticizer contained in the wrap film, leather product, etc., 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 color forming layer, it requires a protective layer and the like. It is possible to impart the plasticizer resistance without having to do so, and it is also excellent in economic efficiency.

Front page continuation (72) Inventor Nobuhiro Kudo 1-30-6 Kamiochiai, Shinjuku-ku, Tokyo Inside Nippon Paper Industries Ltd. Product Development Laboratory (72) Inventor Akio Sekine 5-21 1-1 Prince, Kita-ku, Tokyo Nippon Paper Industries Central Research Institute Co., Ltd.

Claims (1)

[Claims] 1. A thermosensitive recording medium comprising a support and a thermosensitive coloring layer containing a basic colorless dye of a colorless or pale color and an organic developer as main components, wherein the thermosensitive coloring layer is used as a stabilizer. The aminobenzenesulfonamide derivative represented by the general formula (I) is added in an amount of 0.01 to 0.
The methylated fatty acid amide represented by the following general formula (II) is contained in an amount of 9 parts by weight per 0.1 part of the color developer.
A heat-sensitive recording material comprising at least one kind in a ratio of 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. However, n + p ≦ 5
Meet. ) (In the formula, R ₁ represents an alkyl group having 11 to 21 carbon atoms.)