JP2009067048A - Thermal recording material - Google Patents

Abstract

で表される化合物の少なくとも一種とフェノールノボラック系縮合化合物を含有する。
【選択図】なしTo provide a heat-sensitive recording material excellent in storage stability (plasticizer resistance, light resistance, heat resistance) of an image area even under a severe environment.
A heat-sensitive recording medium comprising a heat-sensitive color-developing layer containing a colorless or light-colored dye and two developers on a support, the heat-sensitive color-developing layer having the following general formula

And at least one compound represented by the formula and a phenol novolac condensation compound.
[Selection figure] None

Description

  The present invention relates to a heat-sensitive recording material utilizing a color-forming reaction between an electron-donating leuco dye and an electron-accepting developer, and in particular, a heat-sensitive material having excellent color-forming sensitivity, image area plasticizer resistance, light resistance, and heat resistance. It relates to the record.

In general, a thermosensitive color development mainly composed of a colorless or light-colored electron-donating leuco dye (hereinafter referred to as a dye) and an electron-accepting color developer (hereinafter referred to as a developer) that reacts with the dye when heated to develop a color. Thermal recording materials having layers have been widely put into practical use. In order to perform recording on this thermal recording medium, a thermal printer or the like with a built-in thermal head is used. Compared with other recording systems that have been put to practical use, this thermal recording system has no noise during recording, does not require development and fixing, is maintenance-free, is relatively inexpensive, and is compact. The developed color is very clear, and it is widely used in facsimiles, computer terminal printers, automatic ticket vending machines, measuring recorders, handy terminals used outdoors, and the like. In addition to the output sheets of various devices described above, the thermal recording medium is used in fields such as voucher sheets that require high storage stability.
When the thermal recording material is used for various tickets, receipts, labels, bank ATMs, gas or electric meter readings, or cash vouchers such as car betting tickets, it is in contact with film or synthetic leather for a long time Therefore, there is a demand for plasticizer resistance that does not cause a problem in the readability of the printed part even when stored in a storage medium, and light resistance and heat resistance that do not fade even when exposed to sunlight for a long time.
Therefore, a phenolic compound (Patent Document 1) is used as a developer, or this phenolic compound is used in combination with other developers, sensitizers, stabilizers, etc. (Patent Documents 2 and 3). The technique (patent document 4) etc. which use a phenol condensation composition are indicated.

International Publication No. 2001/025193 Pamphlet JP 2006-297840 A JP 2004-202913 A JP 2003-154760 A

  However, as thermal recording media are increasingly used for applications that are used in harsh environments such as cash vouchers, image storability with higher quality than before has been required. In the current state of the art, sufficient quality is not obtained. Further, when a protective layer is provided on the heat-sensitive recording material, there is a problem that the color development sensitivity and the image quality are deteriorated. Accordingly, an object of the present invention is to provide a heat-sensitive recording material excellent in storage stability of an image portion even under a harsh environment.

で表される化合物の少なくとも一種、及び第二電子受容性顕色剤として下記一般式

（式中、Ｒ^１は、それぞれ同じであっても異なってもよく、ハロゲン原子、水酸基、低級アルキル基、アルコキシル基、シアノ基、ニトロ基、アリール基又はアラルキル基を表し、Ｒ^２は、それぞれ同じであっても異なってもよく、水素原子、アルキル基又はアリール基を表し、ｍは０〜３の整数を表し、ｎは０〜３の整数を表す。）で表される縮合組成物を含有することを特徴とする感熱記録体である。
また本発明は、この感熱発色層上に保護層を有し、該保護層にカルボキシル基含有樹脂、エピクロロヒドリン系樹脂及びポリアミン系樹脂／ポリアミド系樹脂を含有することを特徴とする感熱記録体である。
さらに、本発明は、このポリアミン系樹脂／ポリアミド系樹脂が、ポリアミン系樹脂である上記感熱記録体である。 As a result of intensive studies, the present inventors have found that the above-described problems can be solved by including two specific types of color developer in the thermosensitive coloring layer, and have completed the present invention.
That is, the present invention is a heat-sensitive recording material provided with a heat-sensitive coloring layer containing a colorless or light-colored electron-donating leuco dye and an electron-accepting developer on a support, and the heat-sensitive coloring layer comprises The following general formula as one electron accepting developer

And at least one compound represented by the following general formula as a second electron-accepting developer:

(In the formula, R ¹ each may be the same or different, represent a halogen atom, a hydroxyl group, a lower alkyl group, an alkoxyl group, a cyano group, a nitro group, an aryl group or an aralkyl group, R ² are each The condensation composition may be the same or different and represents a hydrogen atom, an alkyl group or an aryl group, m represents an integer of 0 to 3, and n represents an integer of 0 to 3). It is a heat-sensitive recording material characterized by containing.
The present invention further includes a protective layer on the thermosensitive coloring layer, and the protective layer contains a carboxyl group-containing resin, an epichlorohydrin resin, and a polyamine resin / polyamide resin. Is the body.
Furthermore, the present invention provides the above thermal recording material, wherein the polyamine resin / polyamide resin is a polyamine resin.

Hereinafter, the present invention will be described in more detail.
The heat-sensitive recording material of the present invention comprises a heat-sensitive color developing layer provided on a support, and the heat-sensitive color developing layer contains a dye and two kinds of color developers. The reason why the image portion of the heat-sensitive recording material of the present invention is excellent in plasticizer resistance is that the first color developer and the phenol novolac compound as the second color developer coexist in the heat-sensitive color developing layer. This is probably because the stability of the electron transfer complex, which is a reaction product of the colorant and the basic dye, is increased.

The first developer used in the present invention is represented by the following formula.

Examples of the first developer represented by the above formula include N- (4′-hydroxyphenylthio) acetyl-4-hydroxyaniline (the following formula (a)) and N- (4′-hydroxyphenylthio) acetyl. 2-hydroxyaniline (the following formula (b)), N- (2′-hydroxyphenylthio) acetyl-4-hydroxyaniline, N- (3′-hydroxyphenylthio) acetyl-4-hydroxyaniline, N- ( 2′-hydroxyphenylthio) acetyl-2-hydroxyaniline, N- (3′-hydroxyphenylthio) acetyl-2-hydroxyaniline and the like. These can be used alone or in combination. The first developer is preferably N- (4′-hydroxyphenylthio) acetyl-4-hydroxyaniline, N- (4′-hydroxyphenylthio) acetyl-2-hydroxyaniline, or a mixture thereof. is there.

ここで、Ｒ^１は、同じであっても異なってもよいが、好ましくは同じであって、ハロゲン原子、水酸基、低級アルキル基、アルコキシル基、シアノ基、ニトロ基、アリール基又はアラルキル基を表すが、この中で低級アルキル基、アリール基又はアラルキル基が好ましく、低級アルキル基が特に好ましい。
この低級アルキル基としては３級低級アルキル基が好ましく、更にこの炭素数は好ましく１〜５、より好ましくは１〜４である。この低級アルキル基としては、例えば、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、ｔ−ブチル基、ｔ−アミル基等が挙げられる。
このアルコキシル基の炭素数は好ましくは１〜５であり、アルコキシル基として、例えば、メトキシ基、エトキシ基、プロポキシ基、イソプロポキシ基、ブトキシ基、ｔ−ブトキシ基等が挙げられる。
このアリール基としては、例えば、フェニル基、トリル基、ナフチル基等、好ましくはフェニル基が挙げられ、アラルキル基としては、α−メチルベンジル基、クミル基等が挙げられる。 The phenol novolak compound which is the second developer used in the present invention is represented by the following formula (Formula 2).

Here, R ¹ may be the same or different but is preferably the same and represents a halogen atom, hydroxyl group, lower alkyl group, alkoxyl group, cyano group, nitro group, aryl group or aralkyl group. Of these, a lower alkyl group, an aryl group or an aralkyl group is preferred, and a lower alkyl group is particularly preferred.
The lower alkyl group is preferably a tertiary lower alkyl group, and the carbon number is preferably 1 to 5, more preferably 1 to 4. Examples of the lower alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, and a t-amyl group.
The alkoxyl group preferably has 1 to 5 carbon atoms, and examples of the alkoxyl group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, and a t-butoxy group.
Examples of the aryl group include a phenyl group, a tolyl group, and a naphthyl group, preferably a phenyl group. Examples of the aralkyl group include an α-methylbenzyl group and a cumyl group.

R ² may be the same or different, but is preferably the same and represents a hydrogen atom, an alkyl group or an aryl group, and at least one of ^two R ² bonded to the same carbon is It is preferably a hydrogen atom, and more preferably both are hydrogen atoms.
The alkyl group preferably has 1 to 5 carbon atoms, particularly preferably 1 to 4 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and an n-butyl group. , T-butyl group and the like.
Examples of the aryl group include a phenyl group, a tolyl group, and a naphthyl group, and a phenyl group is preferable.

n represents an integer of 0 to 3. The condensate composition comprising the condensate represented by the general formula (Chemical Formula 2) includes each condensate when n is 0, 1, 2, or 3, and at least two of the four types of condensates. Including a mixture containing the above.
m represents 0 to 3, preferably 1 to 3, and more preferably 1. When m is 1 to 3, R ¹ is preferably bonded to the m-position or p-position of the hydroxyl group of the phenol group, and R ¹ is bonded to the p-position of the hydroxyl group of the phenol group. More preferred.

  Among the condensates represented by the general formula (Chemical Formula 2), specific examples of dinuclear condensates (that is, condensates having two phenol skeletons where n = 0) include, for example, 2,2′-methylenebisphenol. 2,2'-methylenebis (4-chlorophenol), 2,2'-methylenebis (5-chlorophenol), 2,2'-methylenebis (4-hydroxyphenol), 2,2'-methylenebis (5-hydroxy) Phenol), 2,2'-methylenebis (4-methylphenol), 2,2'-methylenebis (5-methylphenol), 2,2'-methylenebis (4-ethylphenol), 2,2'-methylenebis (5 -Ethylphenol), 2,2'-methylenebis (4-n-propylphenol), 2,2'-methylenebis (4-isopropylphenol), 2,2 ' Methylene bis (5-n-propylphenol), 2,2'-methylene bis (5-isopropylphenol), 2,2'-methylene bis (4-n-butylphenol), 2,2'-methylene bis (4-t-butylphenol) 2,2'-methylenebis (5-n-butylphenol), 2,2'-methylenebis (5-t-butylphenol), 2,2'-methylenebis (4-t-amylphenol), 2,2'-methylenebis (4-methoxyphenol), 2,2'-methylenebis (5-methoxyphenol), 2,2'-methylenebis (4-cyanophenol), 2,2'-methylenebis (5-cyanophenol), 2,2 ' -Methylenebis (4-nitrophenol), 2,2'-methylenebis (5-nitrophenol), 2,2'-methyl Bis (4-phenylphenol), 2,2'-methylenebis (5-phenylphenol), 2,2'-methylenebis (4-cumylphenol), 2,2'-methylenebis (5-cumylphenol), 2 2,2'-ethylidenebisphenol, 2,2'-ethylidenebis (4-chlorophenol), 2,2'-ethylidenebis (5-chlorophenol), 2,2'-ethylidenebis (4-hydroxyphenol), 2 2,2'-ethylidenebis (5-hydroxyphenol), 2,2'-ethylidenebis (4-methylphenol), 2,2'-ethylidenebis (5-methylphenol), 2,2'-ethylidenebis (4 -Ethylphenol), 2,2'-ethylidenebis (5-ethylphenol), 2,2'-ethylidenebis (4-n-propyl) Phenol), 2,2'-ethylidenebis (4-isopropylphenol), 2,2'-ethylidenebis (5-isopropylphenol), 2,2'-ethylidenebis (4-n-butylphenol), 2,2 ' -Ethylidenebis (4-t-butylphenol), 2,2'-ethylidenebis (5-n-butylphenol), 2,2'-ethylidenebis (5-t-butylphenol), 2,2'-ethylidenebis (4 -T-amylphenol), 2,2'-ethylidenebis (4-methoxyphenol), 2,2'-ethylidenebis (5-methoxyphenol), 2,2'-ethylidenebis (4-cyanophenol), 2 2,2'-ethylidenebis (5-cyanophenol), 2,2'-ethylidenebis (4-nitrophenol), 2,2'-ethylidene Bis (5-nitrophenol), 2,2'-ethylidenebis (4-phenylphenol), 2,2'-ethylidenebis (5-phenylphenol), 2,2'-ethylidenebis (4-cumylphenol) 2,2'-ethylidenebis (5-cumylphenol), 2,2 '-(phenylmethylene) bisphenol, 2,2'-(phenylmethylene) bis (4-chlorophenol), 2,2 '-( Phenylmethylene) bis (5-chlorophenol), 2,2 '-(phenylmethylene) bis (4-hydroxyphenol), 2,2'-(phenylmethylene) bis (5-hydroxyphenol), 2,2'- (Phenylmethylene) bis (4-methylphenol), 2,2 '-(phenylmethylene) bis (5-methylphenol), 2,2'-(phenyl) Nilmethylene) bis (4-ethylphenol), 2,2 '-(phenylmethylene) bis (5-ethylphenol), 2,2'-(phenylmethylene) bis (4-propylphenol), 2,2 '-( Phenylmethylene) bis (4-isopropylphenol), 2,2 '-(phenylmethylene) bis (5-isopropylphenol), 2,2'-(phenylmethylene) bis (4-t-butylphenol), 2,2 ' -(Phenylmethylene) bis (5-t-butylphenol), 2,2 '-(phenylmethylene) bis (4-t-amylphenol), 2,2'-(phenylmethylene) bis (4-methoxyphenol), 2,2 '-(phenylmethylene) bis (5-methoxyphenol), 2,2'-(phenylmethylene) bis (4-cyanopheno) 2,2 '-(phenylmethylene) bis (5-cyanophenol), 2,2'-(phenylmethylene) bis (4-nitrophenol), 2,2 '-(phenylmethylene) bis (5 -Nitrophenol), 2,2 '-(phenylmethylene) bis (4-phenylphenol), 2,2'-(phenylmethylene) bis (5-phenylphenol) and the like.

  Preferred condensates (binuclear condensates) are 2,2'-methylenebis (4-methylphenol), 2,2'-methylenebis (4-ethylphenol), 2,2'-methylenebis (4-isopropylphenol). 2,2'-methylenebis (4-t-butylphenol), 2,2'-methylenebis (4-n-propylphenol), 2,2'-methylenebis (4-n-butylphenol), 2,2'-methylenebis (4-t-amylphenol), 2,2'-methylenebis (4-cumylphenol), 2,2'-ethylidenebis (4-methylphenol), 2,2'-ethylidenebis (4-ethylphenol) 2,2'-ethylidenebis (4-isopropylphenol), 2,2'-ethylidenebis (4-t-butylphenol), 2,2'- Tylidenebis (4-n-butylphenol), 2,2'-ethylidenebis (4-t-amylphenol), 2,2'-ethylidenebis (4-cumylphenol), 2,2'-butylidenebis (4-methyl) Phenol), 2,2'-butylidenebis (4-t-butylphenol), etc., of which 2,2'-methylenebis (4-methylphenol), 2,2'-methylenebis (4-isopropylphenol), 2 , 2'-methylenebis (4-t-butylphenol), 2,2'-methylenebis (4-n-butylphenol), 2,2'-methylenebis (4-n-propylphenol), 2,2'-methylenebis (4 -T-amylphenol), 2,2'-methylenebis (4-cumylphenol), 2,2'-ethylidenebis (4-t Butylphenol), 2,2'-butylidene bis (4-t-butylphenol) are particularly preferred.

In addition, specific examples of the 3-5 nuclear condensate (that is, the condensate having 3 to 5 phenol skeletons where n = 1 to 3 in the formula) are listed as specific examples of the above binuclear condensate, respectively. Mention may be made of compounds and corresponding compounds.
The condensation composition represented by the general formula (Chemical Formula 2) is a binuclear condensate, or a condensation composition mainly composed of a binuclear condensate and further including at least one of 3 to 5 nuclear condensates. In particular, the condensation composition is mainly composed of a binuclear condensate and further contains at least one of 3 to 5 nuclear condensates. Here, “at least one of 3 to 5 nuclear condensates” means only 3 nuclear condensates, 2 types of 3 nuclear condensates and 4 nuclear condensates, or 3 nuclear condensates and 4 nuclei. This means any of the three types of condensate and pentanuclear condensate, and “mainly binuclear condensate” means that the ratio of dinuclear condensate is the largest among the condensates constituting the condensation composition. Means. In the present invention, the condensation composition represented by the general formula (Chemical Formula 2) is a condensate in which n in the general formula (Chemical Formula 2) which is an impurity is 4 or more as long as the object of the present invention is not impaired. It may be used in the state where (condensate of 6 nuclei or more) coexists.

Specific examples of preferable condensation compositions (condensation compositions mainly composed of binuclear condensates and further containing at least one of 3 to 5 nuclear condensates) include specific examples of the above preferred binuclear condensates. The condensation composition which mainly contains the compound (binuclear condensate) mentioned as above and further contains the 3-5 nuclear condensate corresponding to this is mentioned.
In such a condensation composition, the content of the binuclear condensate is preferably 40 to 99%, more preferably 45 to 98%, and particularly preferably 50 to 80%. That is, when the content of the binuclear condensate in the condensation composition is less than 40% or more than 99%, the effect of improving the sensitivity of the target thermal recording material, the color image and the storage stability of the background is sufficiently obtained. It becomes difficult to express. Here, “%” means “area%” in the results of high performance liquid chromatography analysis.
As the condensation composition composed of the condensate represented by the above general formula (Chemical Formula 2), for example, alkylphenol formalin condensates such as Tomilac 224 (trade name) manufactured by API Corporation can be suitably used.
This alkylphenol formalin condensate can be produced by the method described in International Publication No. 2002/098674 pamphlet. For example, it can be easily obtained by a known synthesis method such as reacting a substituted phenol with a ketone compound or an aldehyde compound in the presence of an acid catalyst (for example, hydrochloric acid, p-toluenesulfonic acid, etc.). The reaction can dissolve the raw materials and reaction products and can be an appropriate organic solvent inert to the reaction (for example, water, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, acetonitrile, toluene, chloroform, diethyl ether, N, N-dimethylacetamide, benzene, chlorobenzene, dichlorobenzene, diethyl ketone, ethyl methyl ketone, acetone, tetrahydrofuran, etc.) at a reaction temperature of 0 to 150 ° C. for several hours to several tens of hours. After the reaction, the unreacted substituted phenols can be obtained with high yield by removing them by distillation.

Specific examples of substituted phenols include phenol, p-chlorophenol, m-chlorophenol, o-chlorophenol, catechol, resorcinol, hydroquinone, p-cresol, m-cresol, o-cresol, p-ethylphenol. M-ethylphenol, o-ethylphenol, p-propylphenol, o-propylphenol, p-isopropylphenol, m-isopropylphenol, o-isopropylphenol, pt-butylphenol, mt-butylphenol, o- t-butylphenol, p-t-amylphenol, p-methoxyphenol, m-methoxyphenol, o-methoxyphenol, p-cyanophenol, m-cyanophenol, o-cyanophenol, p-nitrophenol m-nitrophenol, o-nitrophenol, p-phenylphenol, m-phenylphenol, o-phenylphenol, p-cumylphenol, m-cumylphenol, o-cumylphenol, p- (α-methylbenzyl) ) Phenol and the like.
Specific examples of the ketone compound and the aldehyde compound include, but are not limited to, dimethyl ketone, diethyl ketone, ethyl methyl ketone, methyl isobutyl ketone, formaldehyde, and benzaldehyde.

  In the present invention, other color developers may be used in combination as long as the effects of the present invention are not impaired. As such a developer, any known developer in the field of conventional pressure-sensitive or thermal recording paper can be used, and is not particularly limited. For example, activated clay, attapulgite, colloidal silica, silica Inorganic acidic substances such as aluminum, 4,4′-isopropylidenediphenol, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 4,4 '-Dihydroxydiphenyl sulfide, hydroquinone monobenzyl ether, benzyl 4-hydroxybenzoate, 4,4'-dihydroxydiphenylsulfone, 2,4'dihydroxydiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone, 4-hydroxy -4'-n-propoxydiphenylsulfur Bis (3-allyl-4-hydroxyphenyl) sulfone, 4-hydroxy-4'-methyldiphenylsulfone, 4-hydroxyphenyl-4'-benzyloxyphenylsulfone, 3,4-dihydroxyphenyl-4'-methyl Phenylsulfone, aminobenzenesulfonamide derivatives described in JP-A-8-59603, bis (4-hydroxyphenylthioethoxy) methane, 1,5-di (4-hydroxyphenylthio) -3-oxapentane, bis (p -Hydroxyphenyl) butyl acetate, methyl bis (p-hydroxyphenyl) acetate, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,4-bis [α-methyl-α- (4′- Hydroxyphenyl) ethyl] benzene, 1,3-bis [α-methyl-α- (4′-hydride) Roxyphenyl) ethyl] benzene, di (4-hydroxy-3-methylphenyl) sulfide, 2,2′-thiobis (3-tert-octylphenol), 2,2′-thiobis (4-tert-octylphenol), international publication No. 2002/081229 pamphlet or JP-A No. 2002-301873, thiourea compounds such as N, N′-di-m-chlorophenylthiourea, p-chlorobenzoic acid, stearyl gallate, bis [4- (N-Octyloxycarbonylamino) salicylic acid zinc] dihydrate, 4- [2- (p-methoxyphenoxy) ethyloxy] salicylic acid, 4- [3- (p-tolylsulfonyl) propyloxy] salicylic acid, 5- [ Aromatic of p- (2-p-methoxyphenoxyethoxy) cumyl] salicylic acid Rubonic acid and salts of these aromatic carboxylic acids with polyvalent metal salts such as zinc, magnesium, aluminum, calcium, titanium, manganese, tin and nickel, as well as antipyrine complexes of zinc thiocyanate, terephthalaldehyde acid and others And a composite zinc salt with an aromatic carboxylic acid. These developers can be used alone or in combination of two or more. A metal chelate color-developing component such as a higher fatty acid metal double salt and a polyvalent hydroxyaromatic compound described in JP-A No. 10-258577 can also be contained.

As the dye used in the present invention, any known dyes in the field of conventional pressure-sensitive or thermal recording paper can be used, and are not particularly limited, but include triphenylmethane compounds, fluorane compounds, fluorene compounds. , Divinyl compounds and the like are preferable. Specific examples of typical colorless or light-colored dyes (dye precursors) are shown below. These dye precursors 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) fluorane; 3-diethylamino- 6-methyl-7-chlorofluorane; 3-diethylamino-6-methyl-7- (m-trifluoromethylanilino) fluorane; 3-diethylamino-6-methyl-7- (o-chloroanilino) fluorane; Diethylamino-6-methyl-7- (p-chloroanilino) fluorane; 3-diethylamino-6-methyl-7- (o-fluoroanilino) fluorane; 3-diethylamino-6-methyl-7- (m-methylanilino) fluorane 3-diethylamino-6-methyl-7-n-octylanilinofluorane; 3-diethylamino-6-methyl-7-n-octylaminofluorane; 3-diethylamino-6-methyl-7-benzylaminofluorane; 3-diethylamino-6-methyl-7-dibenzylaminofluorane;
3-diethylamino-6-chloro-7-methylfluorane; 3-diethylamino-6-chloro-7-anilinofluorane; 3-diethylamino-6-chloro-7-p-methylanilinofluorane; 3-diethylamino -6-ethoxyethyl-7-anilinofluorane; 3-diethylamino-7-methylfluorane; 3-diethylamino-7-chlorofluorane; 3-diethylamino-7- (m-trifluoromethylanilino) fluorane; 3-diethylamino-7- (o-chloroanilino) fluorane; 3-diethylamino-7- (p-chloroanilino) fluorane; 3-diethylamino-7- (o-fluoroanilino) fluorane; 3-diethylamino-benzo [a] fluorane ;
3-dibutylamino-6-methyl-7- (o); 3-dibutylamino-6-methyl-7- (o; 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-chlorofluorane; 3-dibutylamino-6-ethoxyethyl-7-anilinofluorane; 3-dibutylamino-6-chloro- 7-anilinofluorane; 3-dibutylamino-6-methyl-7-p-methylanilinofluorane; 3-dibutylamino-7- (o-chloroanilino) fluorane; 3-dibutylamino-7- (o- 3-di-n-pentylamino-6-methyl-7-anilinofluorane; 3-di-n-pentylamino-6-methyl-7- (p-chloroanilino) fluorane; Di-n-pentylamino-7- (m-trifluoromethylanilino) fluorane; 3-di-n-pentylamino-6-chloro-7-anilinofluorane; 3-di-n-pentylamino-7 -(P-chloroanilino) fluorane; 3-pyrrolidino-6-methyl-7-anilinofluorane; 3-piperidino-6-methyl-7-anilinofluorane 3- (N-methyl-N-propylamino) -6-methyl-7-anilinofluorane; 3- (N-methyl-N-cyclohexylamino) -6-methyl-7-anilinofluorane; -(N-ethyl-N-cyclohexylamino) -6-methyl-7-anilinofluorane; 3- (N-ethyl-N-xylamino) -6-methyl-7- (p-chloroanilino) fluorane; (N-ethyl-p-toludino) -6-methyl-7-anilinofluorane; 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluorane; 3- (N- Ethyl (N-isoamylamino) -6-chloro-7-anilinofluorane; 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluorane; Til-N-isobutylamino) -6-methyl-7-anilinofluorane; 3- (N-ethyl-N-ethoxypropylamino) -6-methyl-7-anilinofluorane; 3-cyclohexylamino-6 -Chlorofluorane; 2- (4-oxahexyl) -3-dimethylamino-6-methyl-7-anilinofluorane; 2- (4-oxahexyl) -3-diethylamino-6-methyl-7-ani Linofluorane; 2- (4-oxahexyl) -3-dipropylamino-6-methyl-7-anilinofluorane; 2-methyl-6-p- (p-dimethylaminophenyl) aminoanilinofluorane 2-methoxy-6-p- (p-dimethylaminophenyl) aminoanilinofluorane; 2-chloro-3-methyl-6-p- (p-phenylaminophenyl); 2-chloro-6-p- (p-dimethylaminophenyl) aminoanilinofluorane; 2-nitro-6-p- (p-diethylaminophenyl) aminoanilinofluorane; -Amino-6-p- (p-diethylaminophenyl) aminoanilinofluorane; 2-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluorane; 2-phenyl-6-methyl-6-p -(P-phenylaminophenyl) aminoanilinofluorane; 2-benzyl-6-p- (p-phenylaminophenyl) aminoanilinofluorane; 2-hydroxy-6-p- (p-phenylaminophenyl) Aminoanilinofluorane; 3-methyl-6-p- (p-dimethylaminophenyl) aminoanilinov Oran; 3-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluorane; 3-diethylamino-6-p- (p-dibutylaminophenyl) aminoanilinofluorane; 2,4-dimethyl-6 -[(4-Dimethylamino) anilino] -fluorane

<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)- 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide; 3,6-bis (diethylamino) fluorane-γ- (3′-nitro) anilinolactam; -Bis (diethylamino) fluorane-γ- (4'-nitro) anilinolactam; 1,1-bis- [2 ', 2', 2 ", 2" -tetrakis- (p-dimethyla Nophenyl) -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

  A conventionally well-known sensitizer can be used as a sensitizer used by this invention. Examples of such sensitizers include fatty acid amides such as stearamide and palmitic acid amide, ethylene bisamide, 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-xylene-bis -(Phenyl ether), 4- (m-methyl) Ruphenoxymethyl) biphenyl, 4,4′-ethylenedioxy-bis-benzoic acid dibenzyl ester, dibenzoyloxymethane, 1,2-di (3-methylphenoxy) ethylene, bis [2- (4-methoxy- Examples thereof include, but are not limited to, phenoxy) ethyl] ether, methyl p-nitrobenzoate and phenyl p-toluenesulfonate. These sensitizers may be used alone or in combination of two or more.

In the present invention, 4,4′-butylidene (6-tert-butyl-3-methylphenol), 2 as a stabilizer exhibiting the oil resistance effect of the recorded image and the like within a range not impairing the desired effect on the above problems. 2,2'-di-t-butyl-5,5'-dimethyl-4,4'-sulfonyldiphenol, 1,1,3-tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane and the like.
In the heat-sensitive recording material of the present invention, a fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, acetoacetylated polyvinyl alcohol, carboxy-modified polyvinyl alcohol, amide-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl having a polymerization degree of 200 to 1900 as a binder. Alcohol, butyral modified polyvinyl alcohol, olefin modified polyvinyl alcohol, nitrile modified polyvinyl alcohol, pyrrolidone modified polyvinyl alcohol, silicone modified polyvinyl alcohol, other modified polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, styrene-maleic anhydride copolymer Polymer, styrene-butadiene copolymer and ethyl cellulose, Cellulose derivatives such as chilled cellulose, casein, gum arabic, oxidized starch, etherified starch, dialdehyde starch, esterified starch, polyvinyl chloride, polyvinyl acetate, polyacrylamide, polyacrylate, polyvinyl butyral, polystyrose and the like Examples of such a copolymer include polyamide resin, silicone resin, petroleum resin, terpene resin, ketone resin, and coumaro resin. These polymer substances are used by dissolving them in solvents such as water, alcohol, ketones, esters, hydrocarbons, etc., and are used in the state of being emulsified or pasted in water or other media to achieve the required quality. It can also be used in combination.

Examples of the crosslinking agent used in the present invention include glyoxal, methylol melamine, melamine formaldehyde resin, melamine urea resin, polyamine epichlorohydrin resin, polyamide epichlorohydrin resin, potassium persulfate, ammonium persulfate, sodium persulfate, chloride chloride Examples include ferric iron, magnesium chloride, borax, boric acid, alum, ammonium chloride and the like.
Examples of the pigment used in the present invention include inorganic or organic fillers such as silica, calcium carbonate, kaolin, calcined kaolin, diatomaceous earth, talc, titanium oxide, and aluminum hydroxide.
Examples of the lubricant used in the present invention include fatty acid metal salts such as zinc stearate and calcium stearate, waxes, and silicone resins.
In addition, benzophenone and triazole ultraviolet absorbers, dispersants, antifoaming agents, antioxidants, fluorescent dyes, and the like can be used.

The kind and amount of the dye, developer, and other various components used in the heat-sensitive color forming layer of the present invention are determined according to the required performance and recording suitability, and are not particularly limited. Developer (total) 0.5 to 10 parts by weight, sensitizer 0.5 to 10 parts by weight, stabilizer 0.01 to 10 parts by weight, other components 0.01 to 10 parts by weight Part is used.
Among the developers, the ratio of the first developer to the second developer is preferably 50% by weight or more, more preferably 80% by weight or more, all of which are the first developer and the second developer. Most preferred is a developer. The weight ratio of the second developer to the first developer is preferably 5 to 95% by weight, more preferably 30 to 70% by weight.

  Dye, developer, and materials to be added as needed are finely pulverized to a particle size of several microns or less with a pulverizer such as a ball mill, attritor or sand glider or an appropriate emulsifier, and depending on the binder and purpose. Various additive materials are added to form a coating solution. As a solvent used in the coating liquid, water or alcohol can be used, and the solid content is about 20 to 40% by weight.

In the thermosensitive recording material of the present invention, a protective layer can be further provided on the thermosensitive coloring layer.
The protective layer is often mainly composed of a pigment and a resin. For example, a water-soluble polymer such as polyvinyl alcohol or starch is used as the main component.
In the present invention, it is desirable that the protective layer contains a carboxyl group-containing resin, particularly carboxy-modified polyvinyl alcohol, an epichlorohydrin resin, and a polyamine resin / polyamide resin from the viewpoint of heat resistance, water resistance, and heat and moisture resistance. . The reason is estimated as follows.
A crosslinking reaction (first water resistance) occurs between the carboxyl group of the carboxyl group-containing resin and the amine or amide portion of the epichlorohydrin resin as the crosslinking agent. Next, since the hydrophilic cross-linking site formed of the carboxyl group-containing resin and the epichlorohydrin resin attracts the hydrophilic site of the polyamine resin / polyamide resin, this cross-linking site is polyamine resin / polyamide resin. The resin is encased with the hydrophobic group outside, that is, the hydrophilic crosslinking site is protected from water by the hydrophobic group (second water resistance). Thus, it is presumed that good water resistance and moisture resistance can be obtained by imparting higher hydrophobicity to the reaction site between the resin used in the protective layer and the crosslinking agent.

In particular, when the carboxyl group-containing resin is a carboxy-modified polyvinyl alcohol, the hydrophilic group of the polyamine resin / polyamide resin and the carboxy-modified polyvinyl alcohol is attracted, and the carboxy-modified polyvinyl alcohol has a hydrophobic group of the polyamine resin / polyamide resin. While being encased on the outside, the cationic part of the polyamine resin / polyamide resin is cross-linked with the carboxyl group of the carboxy-modified polyvinyl alcohol, thereby exhibiting high water resistance and heat resistance. It seems to be good.
In addition, a polyamine resin / polyamide resin that has a three-dimensional structure by a crosslinking reaction between carboxy-modified polyvinyl alcohol and an epichlorohydrin resin and is cationic when a pigment is contained in the protective layer. Since the resin exhibits a dispersion effect with respect to the anionic pigment, it is considered that the resin becomes a porous layer as compared with the prior art. For this reason, since the melt of the material with low heat resistance in the coating layer is adsorbed in the voids in the protective layer, excellent print running properties (head debris resistance, sticking resistance) can be exhibited.
In the protective layer of the present invention, it is desirable to use an epichlorohydrin resin and a polyamine resin / polyamide resin in combination. When each of them is used alone, sufficient water resistance cannot be obtained, and adverse effects such as blocking occur. In addition, sufficient water resistance cannot be obtained even when other general crosslinking agents such as glyoxal and epichlorohydrin resin or polyamine resin / polyamide resin are used in combination.

  In the present invention, the carboxyl group-containing resin used as the binder of the protective layer may be any resin having mainly a carboxyl group, such as methacrylic acid, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate. , A resin containing a monofunctional acrylic monomer having a carboxyl group, such as dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, tert-butylaminoethyl methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, oxidized starch, carboxymethylcellulose, Examples include carboxy-modified polyvinyl alcohol in which a carboxyl group is introduced into polyvinyl alcohol. Particularly, carboxy-modified polyvinyl alcohol having excellent heat resistance and solvent resistance. It is preferable to use.

The carboxy-modified polyvinyl alcohol used in the present invention is a product in which a carboxyl group is introduced for the purpose of enhancing the reactivity to a water-soluble polymer, such as polyvinyl alcohol and fumaric acid, phthalic anhydride, melittic anhydride, itaconic anhydride, etc. A reaction product of a polycarboxylic acid, or an esterified product of these reaction products, and an ethylenically unsaturated dicarboxylic acid such as vinyl acetate and maleic acid, fumaric acid, itaconic acid, crotonic acid, acrylic acid or methacrylic acid As a saponified product of Specific examples include the production methods exemplified in JP-A-53-91995.
Furthermore, the carboxy-modified polyvinyl alcohol used in the present invention has a low Hercules viscosity, that is, a high fluidity in a state where a rotational force (share) is applied, and is easily immobilized at a low share. For this reason, it is considered that the coating liquid extends smoothly during coating and solidifies immediately after coating to form a uniform and uniform coating layer, thereby improving the image quality and sensitivity of the printed image. In addition, since carboxy-modified polyvinyl alcohol has high water retention, it can suppress the penetration of the binder into the support, and this effect also improves the image quality and sensitivity because a coating layer without unevenness is formed. It is guessed.
The degree of polymerization and the degree of saponification of the carboxy-modified polyvinyl alcohol used in the present invention can be appropriately selected and used from the viewpoint of the water retention of the paint and the surface strength of the coating layer.

  Specific examples of the epichlorohydrin-based resin used in the present invention include polyamide epichlorohydrin resin, polyamine epichlorohydrin resin, and the like, and they can be used alone or in combination. Moreover, as an amine which exists in the principal chain of an epichlorohydrin-type resin, the thing from a primary to a quaternary can be used, and there is no restriction | limiting in particular. Further, the degree of cationization and the molecular weight preferably have a cationization degree of 5 meq / g · Solid (measured value at pH 7) and a molecular weight of 500,000 or more because of good water resistance. Specific examples are Sumire Resin 650 (30), Sumire Resin 675A, Sumire Resin 6615 (manufactured by Sumitomo Chemical Co., Ltd.), WS4002, WS4020, WS4024, WS4030, WS4046, WS4010, CP8970 (above, Starlight PMC) Manufactured).

In the present invention, “polyamine resin / polyamide resin” means a polyamine resin and / or a polyamide resin, and the “polyamine resin / polyamide resin” includes a polyamide resin, a polyamine resin, and a polyamide urea. Resin, polyethyleneimine resin, polyalkylene polyamine resin, polyalkylene polyamide resin, polyamine polyurea resin, modified polyamine resin, modified polyamide resin, polyalkylene polyamine urea formalin resin, polyalkylene polyamine polyamide polyurea resin, etc. are included, These can use 1 type (s) or 2 or more types.
Specific examples of the polyamine resin / polyamide resin include Sumire Resin 302 (manufactured by Sumitomo Chemical: polyamine polyurea resin), Sumire Resin 712 (Sumitomo Chemical: polyamine polyurea resin), Sumire Resin 703. (Sumitomo Chemical Co., Ltd .: polyamine polyurea resin), Sumire Resin 636 (Sumitomo Chemical Co., Ltd .: polyamine polyurea resin), Sumire Resin SPI-100 (Sumitomo Chemical Co., Ltd .: modified polyamine resin), Sumire Resin SPI-102A (Sumitomo Chemical Co., Ltd .: modified polyamine resin), Sumire Resin SPI-106N (Sumitomo Chemical Co., Ltd .: modified polyamide resin), Sumire Resin SPI-203 (50) (Sumitomo Chemical Co., Ltd .: polyamide resin), Sumirez resin SPI-198 (Sumitomo Chemical Co., Ltd .: polyamide resin), Printe Bu A-700 (manufactured by Asahi Kasei), print A-600 (manufactured by Asahi Kasei), PA 6500 (manufactured by Seiko PMC: polyalkylene polyamine urea formalin resin), PA6504 (manufactured by Seiko PMC: polyalkylene polyamine urea formalin resin) PA 6634, PA 6638, PA 6640, PA 6644, PA 6646, PA 6654, PA 6702, PA 6704 (manufactured by Seiko PMC: polyalkylene polyamine polyamide polyurea resin), CP8994 (manufactured by Seiko PMC: polyethylene imine resin), and the like. Although not limited, polyamine resins (polyalkylene polyamine resins, polyamine polyurea resins, modified polyamine resins, polyalkylene polyamine urea formalin resins, polyalkylene resins from the viewpoint of color development sensitivity are not limited. It is desirable to use the polyamines polyamide polyurea tree).

The content of epichlorohydrin resin and polyamine resin / polyamide resin used in the present invention is preferably 1 to 100 parts by weight, more preferably 5 parts per 100 parts by weight of carboxy-modified polyvinyl alcohol. ~ 50 parts by weight. If the content is too small, the crosslinking reaction becomes insufficient and good water resistance cannot be obtained. If the content is too large, there arises a problem in operability due to an increase in viscosity of the coating liquid or gelation. Moreover, since epichlorohydrin resin cross-links at pH 6.0 or higher, it is desirable to adjust the pH of the protective layer coating to 6.0 or higher.
The types and amounts of various components used in the protective layer of the present invention are determined according to the required performance and recording suitability, and are not particularly limited. Usually, polyvinyl alcohol is 10 to 500 parts per 100 parts by weight of the pigment. It is preferable to use 1 to 100 parts by weight of the crosslinking agent component with respect to 100 parts by weight of polyvinyl alcohol.

These materials are atomized to a particle size of several microns or less by a pulverizer such as a ball mill, attritor, sand glider or an appropriate emulsifier, and various additives are added depending on the binder and purpose to form a coating solution. . As a solvent used for this coating liquid, water or alcohol can be used, and its solid content is about 20 to 40% by weight.
The pigment that can be used in the protective layer in the present invention is kaolin, (calcined) kaolin, calcium carbonate, aluminum oxide, titanium oxide, magnesium carbonate, aluminum silicate, magnesium silicate, calcium silicate, aluminum hydroxide, diatomaceous earth, talc and the like. It is possible. In the present invention, the content of the pigment and binder in the protective layer is about 30 to 300 parts by weight in solid content of the binder with respect to 100 parts by weight of the pigment.

The following examples illustrate the invention but are not intended to limit the invention.
In the following examples and comparative examples, an under layer, a thermosensitive coloring layer (recording layer) and a protective layer were formed on one side of the support, and a back layer was formed on the other side.
The coating liquid used for each coating layer of the heat-sensitive recording material was prepared as follows.
In the description, parts and% indicate parts by weight and% by weight, respectively.
The composition of the second developer (condensation composition represented by the general formula (Chemical Formula 2)) was obtained by analysis by high performance liquid chromatography (HPLC) under the following conditions, and the total area of the constituent components The ratio by the area% of each component when the value is 100 is shown, and other impurities are not included.
Column: Inertsil ODS-2 (particle size: 5μm, column: 4.6mmφ × 15cm)
Eluent: Acetonitrile: 0.05vol% phosphoric acid aqueous solution = 98: 2 (vol)
Flow rate: 0.8mL / min
Wavelength: 280nm
Injection volume: 1.0μL
Column temperature: 40 ° C
Analysis time: 25min
Sample concentration: about 2500ppm

Underlayer coating liquid -calcined kaolin (Ansilex 90 manufactured by BASF) 90.0 parts-styrene-butadiene copolymer latex (solid content 50%) 10.0 parts-water 50.0 parts A mixture comprising the above composition was mixed. The under layer coating solution was prepared by stirring.

Thermosensitive coloring layer coating solution The following solutions A to D were separately wet-ground with a sand grinder until the average particle size became 0.5 μm.
Liquid A (first developer dispersion)
N- (4′-hydroxyphenylthio) acetyl-2-hydroxyaniline (produced by Nippon Soda Co., Ltd., trade name D-102, represented by the general formula (Chem. 3) (b)) 6.0 parts-polyvinyl alcohol 10 % Aqueous solution 5.0 parts-water 1.5 parts B liquid (second developer dispersion)
-Alkylphenol formalin condensate (manufactured by API Corporation, trade name: Tomilac 224) 6.0 parts-Polyvinyl alcohol 10% aqueous solution 5.0 parts-Water 1.5 parts C solution (basic colorless dye dispersion)
-3-dibutylamino-6-methyl-7-anilinofluorane (manufactured by Yamamoto Kasei Co., Ltd., trade name: ODB-2) 6.0 parts-polyvinyl alcohol 10% aqueous solution 5.0 parts-water 1.5 parts D Liquid (sensitizer dispersion)
-Oxalic acid-bisparamethylbenzyl (manufactured by Dainippon Ink and Chemicals, trade name: HS3520) 6.0 parts -Polyvinyl alcohol 10% aqueous solution 5.0 parts -Water 1.5 parts

Next, the dispersions were mixed at the following ratio to obtain a thermosensitive coloring layer coating solution.
Liquid A (first developer dispersion) 18.0 parts Liquid B (second developer dispersion) 18.0 parts Liquid C (basic colorless dye dispersion) 18.0 parts Liquid D (sensitizer) Dispersion) 36.0 parts Silica (manufactured by Mizusawa Chemical Co., Ltd., trade name: P537 25% dispersion) 17.5 parts Polyvinyl alcohol (10% solution) 25.0 parts

Protective layer coating solution- Aluminum hydroxide 50% dispersion (trade name: Martinfin OL, manufactured by Martinsberg) 9.0 parts-Carboxyl-modified polyvinyl alcohol (trade name: KL318 <polymerization degree: about 1700) , Saponification degree: 95 to 99 mol%>) 10% aqueous solution 30.0 parts-Polyamide epichlorohydrin resin (trade name: WS4030, manufactured by Seiko PMC Co., Ltd., solid content 25% <cationization degree: 2.7, molecular weight: 2.2 million, quaternary amine>) 4.0 parts-modified polyamine resin (trade name: Sumirez resin SPI-102A, solid content 45%, manufactured by Sumitomo Chemical Co., Ltd.) 2.2 parts-zinc stearate (product manufactured by Chukyo Yushi Co., Ltd.) Name: Hydrin Z-7-30, solid content 30%) 2.0 parts

[Example 1]
Apply and dry the under layer coating solution on one side of high-quality paper (47 g / m ² base paper) with a Meyer bar to 10.0 g / m ² (fan dryer, 60 ° C., 2 minutes) Coated paper was obtained. The thermosensitive coloring layer coating solution was applied and dried (fan drying at 60 ° C. for 2 minutes) so that the coating amount was 6.0 g / m ² on the under layer of the under-coated paper. This sheet was processed with a super calendar so as to have a smoothness of 500 to 1000 seconds to obtain a heat-sensitive recording material.
[Example 2]
Except for changing D liquid (sensitizer dispersion) to stearic acid amide / paltimic acid amide mixture (mixing ratio: 7/3, Nippon Kasei Co., Ltd., trade name: AP-1), the same procedure as in Example 1 was performed. A heat-sensitive recording material was produced.
[Example 3]
The same as Example 1 except that the liquid C (dye dispersion) was changed to 3-N-di-n-pentylamino-6-methyl-7-anilinofluorane (manufactured by Yamada Chemical Co., Ltd., trade name: BLACK305). Thus, a heat-sensitive recording material was produced.

[Example 4]
A heat-sensitive recording material was prepared with 7.5 parts of the silica compounded part of Example 1, and a coating solution for the protective layer was applied and dried thereon (blow dryer, 60 ° C. at a coating amount of 3 g / m ^2). 2 minutes) to produce a thermal recording material.
[Example 5]
Heat sensitive as in Example 4 except that D liquid (sensitizer dispersion) was changed to stearic acid amide / paltimic acid amide mixture [= 7/3] (product name: AP-1 manufactured by Nippon Kasei Co., Ltd.). A recording body was produced.
[Example 6]
The same as Example 4 except that the liquid C (dye dispersion) was changed to 3-N-di-n-pentylamino-6-methyl-7-anilinofluorane (trade name: BLACK305, manufactured by Yamada Chemical Co., Ltd.). Thus, a heat-sensitive recording material was produced.

[Example 7]
Liquid A (first developer dispersion) was mixed with N- (4′-hydroxyphenylthio) acetyl-2-hydroxyaniline (represented by the general formula (Formula 3) (b)) and N- (4′- Except for changing to a 1: 1 weight ratio mixture of hydroxyphenylthio) acetyl-4-hydroxyaniline (represented by general formula (Chemical Formula 3) (a)) (trade name D-100, manufactured by Nippon Soda Co., Ltd.) A thermosensitive recording material was produced in the same manner as in Example 1.
[Example 8]
A heat-sensitive recording material was produced in the same manner as in Example 4 except that the liquid A (first developer dispersion) was changed to the above D-100.
[Example 9]
A thermosensitive recording material was produced in the same manner as in Example 4 except that the liquid A (first developer dispersion) was changed to 24 parts and the liquid B (second developer dispersion) was changed to 12 parts.
[Example 10]
A thermosensitive recording material was produced in the same manner as in Example 4 except that the liquid A (first developer dispersion) was changed to 12 parts and the liquid B (second developer dispersion) was changed to 24 parts.

[Comparative Example 1]
Liquid A (first developer dispersion) and liquid B (second developer dispersion) into 2,4′-dihydroxydiphenylsulfone (manufactured by Nikka Chemical Co., Ltd., trade name: 2,4′BPS ^* ) A heat-sensitive recording material was produced in the same manner as in Example 1 except for the change.
^* 2,4′BPS is represented by the following equation.

[Comparative Example 2]
The same as Example 1 except that the liquid A (first developer dispersion) and the liquid B (second developer dispersion) were changed to 4-hydroxy-4′-isopropoxydiphenylsulfone represented by the following formula. Thus, a heat-sensitive recording material was produced.

[Comparative Example 3]
A heat-sensitive recording material was produced in the same manner as in Example 1 except that the blending part of the liquid A in Example 1 was 36 parts and the liquid B was not blended.
[Comparative Example 4]
A thermosensitive recording material was produced in the same manner as in Example 1 except that the blending part of the B liquid of Example 1 was 36 parts and the A liquid was not blended.
[Comparative Example 5]
Thermosensitive recording was carried out in the same manner as in Example 4 except that the liquid A (first developer dispersion) and the liquid B (second developer dispersion) were changed to 4-hydroxy-4′-isopropoxydiphenylsulfone. The body was made.
[Comparative Example 6]
The same as Example 1 except that the liquid A (first developer dispersion) and the liquid B (second developer dispersion) were changed to N- (2′-hydroxyphenylthio) acetyl-2-hydroxyaniline. Thus, a heat-sensitive recording material was produced.
[Comparative Example 7]
Thermal recording in the same manner as in Example 1 except that the liquid A (first developer dispersion) was changed to 2,4′-dihydroxydiphenylsulfone (trade name: 2,4′BPS, manufactured by Nikka Chemical Co., Ltd.). The body was made.
[Comparative Example 8]
Thermal recording in the same manner as in Example 1 except that the liquid B (second developer dispersion) was changed to 2,4′-dihydroxydiphenylsulfone (trade name: 2,4′BPS, manufactured by Nikka Chemical Co., Ltd.). The body was made.

The following evaluations were performed on the heat-sensitive recording materials obtained in the above Examples and Comparative Examples, and the results are shown in Table 1.
<Print density>
A checkerboard pattern was printed with a thermal printer TH-PMD applied energy of 0.35 mJ / dot manufactured by Okura Co., Ltd., and the colored portion was measured with a Macbeth densitometer.
<Plasticizer resistance>
Dial wrap (Mitsubishi Resin Co., Ltd.) was brought into contact with the front and back of the thermal recording material printed as described above and left in an environment of 40 ° C. and 90% for 24 hours. The survival rate was calculated from
Residual rate = (printed part density after test) / (printed part density before test) × 100 (%)
◎: Residual rate is 90% or more ○: Residual rate is 75% or more and less than 90% △: Residual rate is 50% or more and less than 75% ×: Residual rate is less than 50%

<Light resistance>
The thermal recording material printed as described above was processed for 24 hours at an output of 67 W / m ^{2 using a} Ci3000F xenon fade meter manufactured by Atlas. The color density printing density before and after the treatment was measured, and the residual ratio was calculated.
◎: Residual rate is 90% or more ○: Residual rate is 75% or more and less than 90% △: Residual rate is 50% or more and less than 75% ×: Residual rate is less than 50% <heat resistance>
A blank paper sample was allowed to stand in an 80 ° C. environment for 24 hours, and the color density before and after the test was measured to obtain the ground color development value.
Ground color development value = color density after test−density before test A: ground color development value less than 0.1 ○: ground color development value is 0.1 or more and less than 0.3 Δ: ground color development value is 0. 3 or more and less than 0.5 ×: Ground color development value is 0.5 or more

The results are shown in the table below.

表１と２から、感熱発色層に本願発明の２種類の顕色剤を含有させた場合には、その感熱記録体が高い印字濃度かつ耐可塑剤性、耐光性及び耐熱性に優れていることがわかる。

From Tables 1 and 2, when the two color developers of the present invention are contained in the thermosensitive coloring layer, the thermosensitive recording material is excellent in high print density, plasticizer resistance, light resistance and heat resistance. I understand that.

Claims (3)

A heat-sensitive recording material provided with a heat-sensitive coloring layer containing a colorless or light-colored electron-donating leuco dye and an electron-accepting developer on a support, the heat-sensitive coloring layer having a first electron-accepting color development The following general formula

And at least one compound represented by the following general formula as a second electron-accepting developer:

(In the formula, R ¹ each may be the same or different, represent a halogen atom, a hydroxyl group, a lower alkyl group, an alkoxyl group, a cyano group, a nitro group, an aryl group or an aralkyl group, R ² are each The condensation composition may be the same or different and represents a hydrogen atom, an alkyl group or an aryl group, m represents an integer of 0 to 3, and n represents an integer of 0 to 3). A heat-sensitive recording material comprising: A thermosensitive recording material comprising a protective layer on the thermosensitive coloring layer, wherein the protective layer contains a carboxyl group-containing resin, an epichlorohydrin resin, and a polyamine resin / polyamide resin. The heat-sensitive recording material according to claim 3, wherein the polyamine resin / polyamide resin is a polyamine resin.