JP6773544B2 - Thermal recording body - Google Patents

Description

The present invention utilizes a color-developing reaction between a colorless or light-colored electron-donating leuco dye (hereinafter, also referred to as “leuco dye”) and an electron-accepting color developer (hereinafter, also referred to as “color developer”). The present invention relates to a heat-sensitive recorder, which has good color development performance under a harsh environment, particularly good bar code reading suitability and heat resistance of a blank sheet portion.

Generally, in a heat-sensitive recorder, a leuco dye having a colorless or light color and a developer such as a phenolic compound are ground and dispersed in fine particles, and then the two are mixed to form a binder, a filler, a sensitivity improver, and the like. A coating liquid obtained by adding a lubricant and other auxiliaries is applied to a support such as paper, synthetic paper, film, plastic, etc., and is used for thermal heads, hot stamps, thermal pens, laser light, etc. Color is developed by an instant chemical reaction by heating, and a recorded image is obtained. Thermal recorders are widely used as recording media for facsimiles, computer terminal printers, automatic ticket vending machines, measurement recorders, receipts in supermarkets and convenience stores, and the like.
In recent years, the use of thermal recorders has expanded to include various tickets, receipts, labels, bank ATMs, gas and electricity meter readings, and gold tickets such as car betting tickets, which are even more severe than ever. It has been required to preserve the image part and the blank part under various conditions, for example, in an environment such as a high temperature state in a car in midsummer.
It is generally known to provide a protective layer on the thermal recording layer as a method for improving the storage stability of the image portion. However, when a protective layer is provided on the heat-sensitive recorder, the protective layer absorbs the heat energy given by the thermal head, so that the color development performance, that is, the color development sensitivity and image quality, especially the barcode reading suitability, is inferior. There is. In particular, when the color development sensitivity is lowered and the contrast between the printed portion and the blank paper portion is reduced, when the barcode is printed, it cannot be read by a reader even if it is visible, and the barcode can be read. There was a problem of insufficient aptitude.
On the other hand, a heat-sensitive recorder (Patent Documents 1 and 2) in which the storage stability of the image portion is improved by using a specific color developer and a stabilizer in combination, or a specific sensitizer and a stabilizer are used in combination. (Patent Document 3) discloses a heat-sensitive recording body (Patent Document 3) in which the storage stability of the image portion is improved.
Further, a thermal recorder (Patent Document 4), a urea compound or a urea urethane compound, and a BPS-based color developer having improved color development performance and storage stability of an image portion by using two specific types of color developer in combination. A heat-sensitive recorder (Patent Documents 5 to 8) whose storage stability is improved by using two kinds of color-developing agents in combination is disclosed.

Japanese Patent Application Laid-Open No. 2003-154760 JP 2001-347757 International release WO2004 / 002748 JP 2006-264255 JP-A-2002-178646 JP 2002-178645 JP 2000-143611 International release WO00 / 014058

When the thermal recorder is used for the above-mentioned labels, tickets, etc., whose applications have been expanding in recent years, the storage stability of the image part and the blank paper part is insufficient.
Further, a thermal recording body (Patent Document 4) or the like using a combination of the above two specific types of color developing agents is inferior in heat resistance of a blank sheet portion, and therefore, when used in an application used in a harsh environment. , The blank part is colored and the barcode reading suitability is insufficient.
Further, in a heat-sensitive recorder (Patent Documents 5 to 8) in which a urea compound or a urea urethane compound and two kinds of color developing agents such as a BPS-based coloring agent are used in combination, the compound and the coloring agent used in the combination may be used. Performance is very different.
Therefore, an object of the present invention is to provide a thermal recording body having good color development performance in a harsh environment, particularly bar code reading suitability and heat resistance of a blank sheet portion. In the present invention, the harsh environment means, for example, high temperature and / or high humidity conditions, the high temperature means, for example, 70 ° C. or higher, and the high humidity means, for example, 80% RH or higher.

（式中、Ｒ^１は水素原子又は水酸基、Ｒ^２及びＲ^３は，それぞれ独立して、水素原子、炭素数１〜６のアルキル基又はアルコキシ基、ｍは１〜３の整数を表す。）

As a result of diligent studies, the present inventors have provided an undercoat layer on the support, and the heat-sensitive recording layer provided on the undercoat layer contains two specific types of color-developing agents in a specific ratio to create a harsh environment. It was found that the readability of the barcode below and the heat resistance of the blank sheet are improved.
The present inventors have also found that the heat resistance of a blank sheet portion under a harsh environment can be further improved by containing a specific amount of hollow plastic particles in the undercoat layer.
That is, the present invention is a heat-sensitive recorder in which an undercoat layer is provided on a support, and a heat-sensitive recording layer containing a colorless or light-colored electron-donating leuco dye and an electron-accepting developer is provided on the undercoat layer. The heat-sensitive recording layer contains a sulfone compound represented by the following general formula (Chemical Formula 1) and a ureaurethane-based compound represented by the following general formula (Chemical Formula 2) as an electron-accepting color developer, and has a general formula. It is a heat-sensitive recorder containing 0.01 to 12.0 parts by weight of the urea urethane compound represented by the general formula (Chemical Formula 2) with respect to 1 part by weight of the sulfone compound represented by (Chemical Formula 1).

(In the formula, R ¹ represents a hydrogen atom or a hydroxyl group, R ² and R ³ independently represent a hydrogen atom, an alkyl group or an alkoxy group having 1 to 6 carbon atoms, and m represents an integer of 1 to 3).

According to the present invention, it is possible to provide a thermal recorder having a good balance of color development performance, particularly bar code reading suitability and heat resistance of a blank sheet portion, even in a harsh environment. Further, by incorporating a specific amount of hollow plastic particles in the undercoat layer, the heat resistance of the blank paper portion under a harsh environment can be further improved.

The heat-sensitive recording material of the present invention comprises an undercoat layer provided on a support, and a heat-sensitive recording layer containing a colorless or light-colored leuco dye and a color developer is provided on the undercoat layer, and the heat-sensitive recording layer is exposed. It contains a specific sulfone compound and a specific urea urethane compound as a colorant in a specific ratio.

この式中、Ｒ^１は水素原子又は水酸基、好ましくは水酸基である。
またＲ^２及びＲ^３は、それぞれ独立して、水素原子、炭素数１〜６、好ましくは炭素数１〜３のアルキル基又はアルコキシ基である。より好ましくは、Ｒ^２及びＲ^３の少なくとも一方が水素原子であり、さらに好ましくはＲ^２及びＲ^３が共に水素原子である。
ｍは１〜３の整数、好ましくは１又は２、より好ましくは１である。 The sulfone compound used in the present invention is represented by the following general formula (Chemical Formula 1).

In this formula, R ¹ is a hydrogen atom or a hydroxyl group, preferably a hydroxyl group.
Further, R ² and R ³ are independently hydrogen atoms, alkyl groups having 1 to 6 carbon atoms, preferably alkyl groups having 1 to 3 carbon atoms, or alkoxy groups. More preferably, at least one of R ² and R ³ is a hydrogen atom, and more preferably both R ² and R ³ are hydrogen atoms.
m is an integer of 1-3, preferably 1 or 2, more preferably 1.

Examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group, tert-pentyl group, 1- Methylbutyl group, 2-methylbutyl group, 1,2-dimethylpropyl group, hexyl group, isohexyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 1,1-dimethylbutyl group, 1, 2-Dimethylbutyl group, 2,2-dimethylbutyl group, 1.3-dimethylbutyl group, 2,3-dimethylbutyl group, 3,3-dimethylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, 1, Linear or branched carbon number 1-6 such as 1,2-trimethylpropyl group, 1,2,2-trimethylpropyl group, 1-ethyl-1-methylpropyl group, 1-ethyl-2-methylpropyl group The alkyl group is preferably an alkyl group having 1 to 3 carbon atoms, that is, a methyl group, an ethyl group, a propyl group or an isopropyl group.
The alkoxy group includes a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, a pentyloxy (amyloxy) group, an isopentyloxy group, and a tert-. Examples thereof include linear or branched alkoxy groups having 1 to 6 carbon atoms such as a pentyloxy group, a neopentyloxy group, a 2-methylbutoxy group, a 1,2-dimethylpropoxy group, a 1-ethylpropoxy group, and a hexyloxy group. It is preferably a methoxy group, an ethoxy group, a propoxy group, or an isopropoxy group.

この式中、Ｒ^２、Ｒ^３及びｍは上記と同様に定義される。
本発明で用いられる更に好ましいスルホン化合物として、４−ヒドロキシ−４'−ベンジルオキシジフェニルスルホン、４−ヒドロキシ−４'−フェネチルオキシジフェニルスルホン、４−ヒドロキシ−４'−（３−フェニルプロポキシ）ジフェニルスルホンが挙げられ、最も好ましくは４−ヒドロキシ−４'−ベンジルオキシジフェニルスルホン（下式）である。

The preferred sulfone compound used in the present invention is represented by the following general formula (Chemical Formula 3).

In this ^formula, R 2, ^{R 3} and m are as defined above.
More preferred sulfone compounds used in the present invention are 4-hydroxy-4'-benzyloxydiphenylsulfone, 4-hydroxy-4'-phenethyloxydiphenylsulfone, 4-hydroxy-4'-(3-phenylpropoxy) diphenylsulfone. , And most preferably 4-hydroxy-4'-benzyloxydiphenyl sulfone (formula below).

The urea urethane compound used in the present invention is represented by the following general formula (Chemical Formula 2).

When the heat-sensitive recording layer of the present invention contains a sulfone compound represented by the general formula (Chemical formula 1) and a urea urethane compound represented by the general formula (Chemical formula 2) as a color developer, it is represented by the general formula (Chemical formula 1). Since the oxygen atom of the aralkyloxy group of the sulfone compound takes in π electrons from the aralkyl group and has a high electronegativity, it becomes basic when heated and melted.
In a basic environment, the urea urethane compound tends to be in the enol type, so that the reaction efficiency between the urea urethane compound and the leuco dye is particularly increased, an electron transfer complex is easily formed, and a reverse reaction is less likely to occur. As a result, it is presumed that the color development performance of the obtained thermal recording body, particularly the bar code reading suitability, is good, and the heat resistance of the blank sheet portion is also excellent.

The urea urethane compounds used as the color developer in the present invention are specifically three types represented by the following formulas (Chemical formulas 5) to (Chemical formula 7), and these are used alone or in combination of two or more. May

As a color developer, the heat-sensitive recording layer of the present invention contains 0.01 to 12. a urea urethane compound represented by the general formula (Chemical Formula 2) with respect to 1 part by weight of the sulfone compound represented by the general formula (Chemical Formula 1). Contains 0 parts by weight. Further, the heat-sensitive recording layer contains a urea urethane-based compound in an amount of preferably 0.05 parts by weight or more, more preferably 0.1 parts by weight or more, based on 1 part by weight of the sulfone compound. Further, the heat-sensitive recording layer contains a ureaurethane-based compound, preferably 10.0 parts by weight or less, more preferably 3.0 parts by weight or less, still more preferably 1.1 parts by weight or less, based on 1 part by weight of the sulfone compound. It is particularly preferably contained in an amount of 0.5 parts by weight or less, and most preferably less than 0.5 parts by weight.
When the content ratio of the urea urethane compound represented by the general formula (Chemical Formula 2) to the sulfone compound represented by the general formula (Chemical Formula 1) is within this range, the color development performance of the heat-sensitive recorder under a harsh environment, In particular, the bar code readability is the best (see the examples below). If the amount of the urea urethane compound represented by the general formula (Chemical Formula 2) is less than 0.01 parts by weight with respect to 1 part by weight of the sulfone compound represented by the general formula (Chemical Formula 1), the barcode reading suitability is sufficient. It may not be. Further, when the amount of the urea urethane compound exceeds 1.1 parts by weight with respect to 1 part by weight of the sulfone compound, the whiteness of the blank portion may tend to decrease.

The heat-sensitive recording layer of the present invention may contain a color developer other than the sulfone compound represented by the general formula (Chemical Formula 1) and the urea urethane compound represented by the general formula (Chemical Formula 2) as the color developer. .. However, the total content of the sulfone compound represented by the general formula (Chemical Formula 1) and the urea urethane compound represented by the general formula (Chemical Formula 2) is the total color developer contained in the heat-sensitive recording layer (general). The sulfone compound represented by the formula (Chemical formula 1) and the urea urethane compound represented by the general formula (Chemical formula 2) are preferably 50% by weight or more, more preferably 70% by weight or more, and further. It is preferably 90% by weight or more, particularly preferably 100% by weight, that is, the total color developer contained in the heat-sensitive recording layer is a sulfone compound represented by the general formula (Chemical Formula 1) and a general formula (Chemical Formula 2). It is a urea urethane compound represented.

Examples of the color-developing agent other than the sulfone compound represented by the general formula (Chemical Formula 1) and the urea urethane-based compound represented by the general formula (Chemical Formula 2) used in the present invention include active white clay, attapulsite, colloidal silica, and the like. Inorganic acidic substances such as aluminum silicate, 4,4'-isopropyridene diphenol, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 4, 4'-dihydroxydiphenylsulfide, hydroquinone monobenzyl ether, benzyl 4-hydroxybenzoate, 4,4'-dihydroxydiphenylsulfone, 2,4'-dihydroxydiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone, 4 -Hydroxy-4'-n-propoxydiphenyl sulfone, 4-hydroxy-4'-allyloxydiphenyl sulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, 4-hydroxy-4'-methyldiphenyl sulfone, 3, 4-Dihydroxyphenyl-4'-methylphenyl sulfone, 1- [4- (4-hydroxyphenylsulfonyl) phenoxy] -4- [4- (4-isopropoxyphenylsulfonyl) phenoxy] butane, JP-A-2003-154760 Phenol condensation composition described in JP-A, aminobenzene sulfone amide derivative described in JP-A-8-59603, bis (4-hydroxyphenylthioethoxy) methane, 1,5-di (4-hydroxyphenylthio) -3-oxa. Pentan, bis (p-hydroxyphenyl) butyl acetate, bis (p-hydroxyphenyl) methyl 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'-hydroxyphenyl) ethyl] benzene, di (4-hydroxy-3-methylphenyl) sulfide, 2, 2'-thiobis (3-tert-octylphenol), 2,2'-thiobis (4-tert-octylphenol), phenolic compounds such as the diphenylsulfone cross-linked compound described in WO 97/16420, WO 02/081229 or special Compounds described in Kai 2002-301873, thiourea compounds such as N, N'-di-m-chlorophenylthiourea, p-chlorobenzoic acid, stearyl gallate, bis [4- ( n-octyloxycarbonylamino) zinc salicylate] dihydrate, 4- [2- (p-methoxyphenoxy) ethyloxy] salicylic acid, 4- [3- (p-tolylsulfonyl) propyloxy] salicylic acid, 5- [p -(2-p-methoxyphenoxyethoxy) cumyl] With aromatic carboxylic acids of salicylic acid and polyvalent metal salts of these aromatic carboxylic acids such as zinc, magnesium, aluminum, calcium, titanium, manganese, tin and nickel. Examples thereof include salts, an antipyrine complex of zinc thiosocyanate, and a composite zinc salt of terephthalaldehyde acid and another aromatic carboxylic acid. These color developers may be used alone or in combination of two or more. 1- [4- (4-Hydroxyphenylsulfonyl) phenoxy] -4- [4- (4-isopropoxyphenylsulfonyl) phenoxy] butane is available, for example, under the trade name JKY-214 manufactured by AP Corporation. The phenol condensation composition described in JP-A-2003-154760 is available, for example, under the trade name JKY-224 manufactured by IP Corporation, and is a diphenyl sulfone cross-linked compound described in International Publication No. WO 97/16420. Is available under the trade name D-90 manufactured by Nippon Soda Co., Ltd. Further, the compound described in WO02 / 081229 etc. is available under trade names NKK-395 and D-100 manufactured by Nippon Soda Corporation. In addition, a metal chelate type color-developing component such as a higher fatty acid metal double salt or a polyvalent hydroxy aromatic compound described in JP-A No. 10-258577 can also be contained.

Next, various materials used in the heat-sensitive recording layer of the heat-sensitive recording body of the present invention will be illustrated, but binders, cross-linking agents, pigments and the like are provided as necessary within a range that does not impair the desired effect on the above-mentioned problems. It can also be used as a coating layer other than the heat-sensitive recording layer, that is, a protective layer, an undercoat layer, or the like.

As the leuco dye used in the present invention, all conventional leuco dyes known in the field of pressure-sensitive or thermal recording paper can be used, and are not particularly limited, but are triphenylmethane-based compounds, fluorene-based compounds, and fluorene. Fluorene compounds, divinyl compounds and the like are preferable. Specific examples of typical colorless or light-colored dyes (dye precursors) are shown below. In addition, 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]

<Fluorine 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, 3- 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-chlorofluorine, 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-diethylamino-benzo [c] fluorane, 3-dibutylamino-6-methyl-fluorane, 3-dibutylamino-6-methyl-7- Anilinofluolane, 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-trifluoromethyl) Anilino) Fluoran, 3-dibutylamino- 6-Methyl-7-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-fluoroanilino) fluorane, 3-di-n-pentylamino -6-Methyl-7-anilinofluorane, 3-di-n-pentylamino-6-methyl-7- (p-chloroanilino) fluorane, 3-di-n-pentylamino-7- (m-trifluoro) Methylanilino) 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, 3- (N-ethyl-N-cyclohexylamino) -6-methyl-7-anilinofluorane, 3- (N) -Ethyl-N-xylamino) -6-methyl-7- (p-chloroanilino) fluorane, 3- (N-ethyl-p-toluidino) -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, 3- (N-ethyl-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-anilino Fluoran, 2- (4-oxahexyl) -3-diethylamino-6-methyl-7-anilinofluorane, 2- (4-oxahexyl) -3-dipropylamino-6-methyl-7-anilino Fluorane, 2-methyl-6-p- (p-dimethylaminophenyl) aminoanilinofluorane, 2-methoxy-6-p -(P-Dimethylaminophenyl) aminoanilinofluorane, 2-chloro-3-methyl-6-p- (p-phenylaminophenyl) aminoanilinofluorane, 2-chloro-6-p- (p-) Dimethylaminophenyl) aminoanilinofluorane, 2-nitro-6-p- (p-diethylaminophenyl) aminoanilinofluorane, 2-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-dimethylamino) Phenyl) aminoanilinofluorane, 3-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluorane, 3-diethylamino-6-p- (p-dibutylaminophenyl) aminoanilinofluorane, 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- Il] -4,5,6,7-tetrachlorophthalide

<Others>
3- (4-Diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methylindole-3-yl) -4-azaphthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- ( 1-octyl-2-methylindole-3-yl) -4-azaphthalide, 3- (4-cyclohexylethylamino-2-methoxyphenyl) -3- (1-ethyl-2-methylindole-3-yl)- 4-Azaphthalide, 3,3-bis (1-ethyl-2-methylindole-3-yl) phthalide, 3,6-bis (diethylamino) fluoran-γ- (3'-nitro) anilinolactam, 3,6 -Bis (diethylamino) fluorane-γ- (4'-nitro) anilinolactam, 1,1-bis- [2', 2', 2'', 2''-tetrax- (p-dimethylaminophenyl)- Ethenyl] -2,2-dinitrile ethane, 1,1-bis- [2', 2', 2'', 2''-tetrax- (p-dimethylaminophenyl) -ethenyl] -2-β-naphthylethane , 1,1-bis- [2', 2', 2'', 2''-tetrakis- (p-dimethylaminophenyl) -ethenyl] -2,2-diacetylethane, bis- [2,2,2 ', 2'-Tetrax- (p-dimethylaminophenyl) -ethenyl] -methylmalonic acid dimethyl ester

As the sensitizer used in the present invention, a conventionally known sensitizer can be used. Examples of such sensitizers include fatty acid amides such as stearate amide and palmitate amide, ethylene bisamide, montanic acid wax, polyethylene wax, 1,2-bis- (3-methylphenoxy) ethane, p-benzylbiphenyl and β-. Benzyloxynaphthalene, 4-biphenyl-p-tolyl ether, m-terphenyl, 1,2-diphenoxyetane, 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-methylphenoxymethyl) biphenyl, 4,4'-ethylenedioxy-bis-benzoic acid dibenzyl ester, dibenzoyloxymethane, 1,2-di (3-methylphenoxy) Examples thereof include ethylene, bis [2- (4-methoxy-phenoxy) ethyl] ether, methyl p-nitrobenzoate, phenyl p-toluenesulfonate, o-toluenesulfonamide, p-toluenesulfonamide and the like. These sensitizers may be used alone or in combination of two or more.

Examples of the pigment used in the present invention include kaolin, calcined kaolin, calcium carbonate, aluminum oxide, titanium oxide, magnesium carbonate, aluminum silicate, magnesium silicate, calcium silicate, aluminum hydroxide, silica and the like, depending on the required quality. It can also be used together.

Examples of the binder used in the present invention include fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, acetoacetylated polyvinyl alcohol, carboxy-modified polyvinyl alcohol, amide-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, butyral-modified polyvinyl alcohol, and olefin-modified. Polyvinyl alcohols such as polyvinyl alcohol, nitrile-modified polyvinyl alcohol, pyrrolidone-modified polyvinyl alcohol, silicone-modified polyvinyl alcohol, and other modified polyvinyl alcohols, (meth) acrylic acid, and monomer components that can be copolymerized with (meth) acrylic acid. Acrylic resin (excluding olefins), hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, ethyl cellulose, acetyl cellulose and other cellulose derivatives, oxidized starch, etherified starch, esterified starch and other starches, styrene-maleic anhydride Copolymers, styrene-butadiene copolymers, casein, arabia rubber, polyvinyl chloride, polyvinyl acetate, polyacrylamide, polyacrylic acid ester, polyvinyl butyral, polystyrose and their copolymers, polyamide resin, silicone resin, petroleum Examples thereof include resins, terpene resins, ketone resins, and kumaron resins. These polymer substances are used by dissolving them in solvents such as water, alcohols, ketones, esters, and hydrocarbons, and are also used in a state of being emulsified or dispersed in a paste in water or other media to achieve the required quality. It can also be used together depending on the situation.
The content (solid content) of the binder in the thermal recording layer is preferably about 5 to 25% by weight.

Examples of the cross-linking agent used in the present invention include zirconium chloride, zirconium sulfate, zirconium nitrate, zirconium acetate, zirconium carbonate, zirconium stearate, zirconium octylate, zirconium silicate, zirconium oxynitrate, potassium zirconium carbonate, ammonium carbonate and the like. Zirconium compounds, glioxal, glutaaldehyde, polyvalent aldehyde compounds such as aldehyde starch, methylol melamine, melamine formaldehyde resin, melamine urea resin, polyamine epichlorohydrin resin, polyamide epichlorohydrin resin, potassium persulfate, ammonium persulfate, Examples thereof include sodium persulfate, ferric chloride, magnesium chloride, boar sand, boric acid, myoban, and ammonium chloride.

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 the present invention, 4,4'-butylidene (6-t-butyl-3-methylphenol), 2 as a stabilizer for improving the oil resistance of the image portion, etc., as long as the desired effect on the above problems is not impaired. , 2'-di-t-butyl-5,5'-dimethyl-4,4'-sulfonyldiphenol, 1,1,3-tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 1 , 1,3-Tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane and the like can also be added. In addition, benzophenone-based or triazole-based ultraviolet absorbers, dispersants, antifoaming agents, antioxidants, fluorescent dyes and the like can be used.

The types and amounts of the leuco dye, the color developer, the sensitizer, and various other components used in the heat-sensitive recording layer of the present invention are determined according to the required performance and recording suitability, and are not particularly limited. Usually, 0.5 to 10 parts by weight of a developer, 0.1 to 10 parts by weight of a sensitizer, 0.5 to 20 parts by weight of a pigment, and 0.01 to 10 parts by weight of a stabilizer with respect to 1 part by weight of leuco dye. Parts and other components 0.01 to 10 parts by weight are used.

In the present invention, the leuco dye, the color developer, and the material to be added as needed are atomized by a crusher such as a ball mill, an attritor, a sand glider, or a suitable emulsifier to a particle size of several microns or less, and the binder is used. And various additive materials are added according to the purpose to make a coating liquid. Water, alcohol, or the like can be used as the solvent used in this coating liquid, and the solid content thereof is about 20 to 40% by weight.

In the heat-sensitive recording body of the present invention, an undercoat layer is provided between the support and the heat-sensitive recording layer.
This undercoat layer mainly consists of a binder and a pigment.
As the binder used for the undercoat layer, a binder that can be used for the above-mentioned heat-sensitive recording layer can be appropriately used. These binders may be used alone or in combination of two or more.

As the pigment used for the undercoat layer, known pigments generally used in the past, specific examples thereof include calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, magnesium hydroxide, kaolin, calcined kaolin, clay, and the like. Inorganic pigments such as talc and organic pigments such as hollow plastic particles can be used. These pigments may be used alone or in combination of two or more.
The plastic hollow particles of the present invention are fine hollow particles that have a thermoplastic resin as a shell and contain air or other gas inside, and are already in a foamed state. Examples of thermoplastic resins include polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyacrylic acid esters, polyacrylonitrile, polybutadiene, and copolymers thereof. In particular, a styrene resin such as polystyrene, an acrylic resin such as a polyacrylic acid ester or a polyacrylic nitrile, a copolymer thereof, or a copolymer resin mainly composed of polyvinylidene chloride and polyacrylonitrile is preferable. Such organic hollow particles are available as SX8782 manufactured by JSR Corporation, MH5055 and MH8108A manufactured by ZEON Corporation, ROHM & Hearth Japan Co., Ltd. Low Pake HP-91, and Matsumoto Oil & Fat Co., Ltd. Microsphere.
The volume hollow ratio of the plastic hollow particles of the present invention is preferably about 40 to 95%. By setting the volume hollow ratio to 40% or more, the heat insulating property can be improved and the color development performance can be further improved. On the other hand, when the content is 95% or less, the strength of the shell of the hollow particles is increased to effectively maintain the hollow state, and it becomes easy to obtain an undercoat layer having good surface strength. Here, the volume hollow ratio is a value obtained by (d3 / D3) × 100. In the formula, d indicates the inner diameter of the organic hollow particles, and D indicates the outer diameter of the organic hollow particles.

The pigment in the undercoat layer is usually 50 to 95 parts by weight, preferably 70 to 90 parts by weight, based on 100 parts by weight of the total solid content.
In the present invention, the undercoat layer preferably contains plastic hollow particles as a pigment. When the undercoat layer contains plastic hollow particles as the pigment, the undercoat layer preferably contains 45% by weight or more of the plastic hollow particles with respect to the total amount (solid content) of the pigment.
As the pigment other than the plastic hollow particles contained in the undercoat layer, the above-mentioned inorganic pigment can be used, but calcined kaolin is preferably used.
If necessary, various auxiliary agents such as dispersants, plasticizers, pH adjusters, defoamers, water retention agents, preservatives, coloring dyes, and UV protection agents may be added to the coating liquid of the undercoat layer. Good.

The thermal recording body of the present invention may further have a protective layer on the thermal recording layer.
This protective layer is mainly composed of a binder and a pigment, to which a cross-linking agent may be further added.
As the binder, a binder that can be used for the above-mentioned heat-sensitive recording layer can be appropriately used, but carboxy-modified polyvinyl alcohol and a non-core-shell acrylic resin having a glass transition point (Tg) higher than 50 ° C. are preferable. These binders may be used alone or in combination of two or more.
Further, as the cross-linking agent, the cross-linking agent that can be used for the above-mentioned heat-sensitive recording layer can be appropriately used, but epichlorohydrin-based resin and polyamine / polyamide-based resin (those contained in epichlorohydrin-based resin) are used. Excludes) is preferable.
It is more preferable that the protective layer contains an epichlorohydrin-based resin and a polyamine / polyamide-based resin together with carboxy-modified polyvinyl alcohol, which further improves the color development performance.

This carboxy-modified polyvinyl alcohol is, for example, a reaction product of polyvinyl alcohol and a polyvalent carboxylic acid such as fumaric acid, phthalic acid anhydride, meritonic acid anhydride, itaconic acid anhydride, an esterified product of these reactants, and vinyl acetate. It is obtained as a saponification of a copolymer with an ethylenically unsaturated dicarboxylic acid such as maleic acid, fumaric acid, itaconic acid, crotonic acid, acrylic acid and methacrylic acid. Specific examples of the manufacturing method include the methods exemplified in JP-A-53-91995. The saponification degree of the carboxy-modified polyvinyl alcohol is preferably 72 to 100 mol%, and the degree of polymerization is 500 to 2400, more preferably 1000 to 2000.

The glass transition point (Tg) of this non-core shell type acrylic resin is higher than 50 ° C., preferably 95 ° C. or lower. This Tg is measured by differential scanning calorimetry (DSC).
This non-core shell type acrylic resin contains (meth) acrylic acid and a monomer component copolymerizable with (meth) acrylic acid, and (meth) acrylic acid is 1 in 100 parts by weight of the non-core shell type acrylic resin. It is preferably 10 parts by weight. (Meta) acrylic acid is alkali-soluble and has the property of turning a non-core-shell acrylic resin into a water-soluble resin by adding a neutralizing agent. By changing the non-core shell type acrylic resin to a water-soluble resin, the bondability to the pigment is remarkably improved, especially when the protective layer contains a pigment, and the protective layer has excellent strength even when a large amount of pigment is contained. Can be formed. Examples of the components copolymerizable with (meth) acrylic acid include methyl (meth) acrylic acid, ethyl (meth) acrylic acid, propyl (meth) acrylic acid, butyl (meth) acrylic acid, and isobutyl (meth) acrylic acid. By alkyl acrylate resins such as pentyl (meth) acrylate, hexyl (meth) acrylate, -2-ethylhexyl (meth) acrylate, octyl acrylate and epoxy resins, silicone resins, styrene or derivatives thereof. Modified alkyl acrylate resins such as the modified alkyl acrylate resin, (meth) acrylonitrile, acrylic acid ester, and hydroxyalkyl acrylate ester can be exemplified, and in particular, (meth) acrylonitrile and / or methyl methacrylate may be blended. Is preferable. It is preferable to blend 15 to 70 parts of (meth) acrylonitrile out of 100 parts of the non-core shell type acrylic resin. Further, it is preferable that methyl methacrylate is contained in an amount of 20 to 80 parts out of 100 parts of a non-core shell type acrylic resin. When (meth) acrylonitrile and methyl methacrylate are contained, 15 to 18 parts of (meth) acrylonitrile are blended in 100 parts of the non-core shell acrylic resin, and 20 to 80 parts of methyl methacrylate are blended in 100 parts of the non-core shell acrylic resin. Is preferable.

This epichlorohydrin-based resin is a resin characterized by containing an epoxy group in the molecule, and examples thereof include polyamide epichlorohydrin resin and polyamine epichlorohydrin resin. These can be used alone or in combination. Further, as the amine present in the main chain of the epichlorohydrin-based resin, primary to quaternary amines can be used, and there is no particular limitation. Further, since the water resistance is good, the degree of cationization and the molecular weight are preferably 5 meq / g · Solid or less (measured value at pH 7) and a molecular weight of 500,000 or more. Specific examples of the epichlorohydrin resin include Sumire's Resin 650 (30), Sumire's Resin 675A, Sumire's Resin 6615 (all manufactured by Sumitomo Chemical Corporation), WS4002, WS4020, WS4024, WS4030, WS4046, WS4010, CP8970 (all manufactured by Seiko PMC) and the like can be mentioned.

This polyamine / polyamide resin does not have an epoxy group in the molecule, for example, polyamide urea resin, polyalkylene polyamine resin, polyalkylene polyamide resin, polyamine polyurea resin, modified polyamine resin, modified polyamide resin, polyalkylene polyamine. Examples thereof include urea formalin resins and polyalkylene polyamine polyamide polyurea resins, which can be used alone or in combination. Specific examples of the polyamine / polyamide resin include Sumire's Resin 302 (Sumitomo Chemical Co., Ltd .: Polyamine Polyurea Resin), Sumire's Resin 712 (Sumitomo Chemical Co., Ltd .: Polyamine Polyurea Resin), and Sumire's Resin 703 (Sumitomo Chemical Co., Ltd.). Co., Ltd .: Polyamine polyurea resin), Sumire's resin 636 (Sumitomo Chemical Co., Ltd .: Polyamine polyurea resin), Sumire's resin SPI-100 (Sumitomo Chemical Co., Ltd .: Modified polyamine resin), Sumire's resin SPI-102A (Sumitomo) Chemicals: Modified polyamine resin), Sumires resin SPI-106N (Sumitomo Chemicals: Modified polyamide resin), Sumires resin SPI-203 (50) (Sumitomo Chemical), Sumires resin SPI-198 (Sumitomo) Chemicals), Printive A-700, Printive A-600 (above, manufactured by Asahi Kasei), PA6500, PA6504, PA6634, PA6638, PA6640, PA6644, PA6664, PA6654, PA6702, PA6704 (above, manufactured by Seikou PMC) : Polyalkylene polyamine polyamide polyurea resin), CP8994 (manufactured by Seikou PMC: polyethylene imine resin) and the like. Although there is no particular limitation, polyamine-based resins (polyalkylene polyamine resin, polyamine polyamine resin, modified polyamine resin, polyalkylene polyamine urea formalin resin, polyalkylene polyamine polyamide polyurea resin) are used because the print density is good. Is preferable.

When an epichlorohydrin-based resin and a polyamine / polyamide-based resin are used together with carboxy-modified polyvinyl alcohol for the protective layer, the content is preferably 1 to 100 parts by weight with respect to 100 parts by weight of carboxy-modified polyvinyl alcohol. , 5 to 50 parts by weight, more preferably 10 to 40 parts by weight.

As the pigment used for the protective layer, the pigment that can be used for the above-mentioned heat-sensitive recording layer can be appropriately used, but kaolin, calcined kaolin, aluminum hydroxide, and silica are preferable. These pigments may be used alone or in combination of two or more.
The content (solid content) of the binder in the protective layer is preferably 20% by weight or more, more preferably about 20 to 80% by weight, and when the protective layer contains a pigment, the content of the pigment and the binder is 100 parts by weight of the pigment. On the other hand, the binder preferably has a solid content of about 30 to 300 parts by weight.
If necessary, the coating liquid for the protective layer may contain cross-linking agents, lubricants, stabilizers, ultraviolet absorbers, dispersants, defoamers, antioxidants, fluorescent dyes, etc. that can be used for the above-mentioned heat-sensitive recording layer. Various auxiliary agents may be appropriately blended.

In the present invention, the means for coating the coating layer other than the thermal recording layer and the thermal recording layer is not particularly limited, and the coating layer can be applied according to a well-known conventional technique. For example, an off-machine coating machine or an on-machine coating machine equipped with various coaters such as an air knife coater, a rod blade coater, a vent blade coater, a bevel blade coater, a roll coater, and a curtain coater is appropriately selected and used.
The coating amount of the thermal recording layer and the coating layer other than the thermal recording layer is determined according to the required performance and recording suitability, and is not particularly limited, but the general coating amount of the thermal recording layer is solid. It is about ² to 12 g / m ² per minute. Moreover, typical coating amount of the undercoat layer is 1 to 15 g / m ² approximately in solids, general coating amount of the protective layer is 1 to 5 g / m ² approximately in solids. In the present invention, the coating amount of the protective layer is preferably 1 to 3 g / m ² in terms of solid content.
In addition, various known techniques in the field of thermal recording materials can be added as necessary, such as performing a smoothing treatment such as super calendar hanging after coating each layer.

Hereinafter, the present invention will be illustrated in Examples, but it is not intended to limit the present invention. In each of the Examples and Comparative Examples, "parts" indicates "parts by weight" and "%" indicates "% by weight" unless otherwise specified. Various dispersions and coating solutions were prepared as follows.

[Preparation of each coating liquid]
The formulation consisting of the following formulations was stirred and dispersed to prepare coating liquids 1 and 2 for the undercoat layer.
<Coating liquid for undercoat layer 1>
Calcined kaolin (manufactured by BASF, trade name: Ansilex 90) 100.0 parts Styrene-butadiene copolymer latex (manufactured by Zeon Corporation, Japan)
Product name: ST5526, solid content 48%) 10.0 parts Water 50.0 parts <Coating liquid 2 for undercoat layer>
Baked kaolin (manufactured by BASF, trade name: Ancilex 90) 50.0 parts Plastic hollow particles (manufactured by Zeon Corporation, trade name: Nipol MH8108A,
Hollow ratio 50%, solid content 27%) 185.0 parts Styrene-butadiene copolymer latex (manufactured by ZEON CORPORATION,
Product name: ST5526, solid content 48%) 10.0 copies

The developer dispersions (solutions A1 to A8), leuco dye dispersions (solution B), and sensitizer dispersions (solution C) having the following formulations are separately prepared with a sand grinder to an average particle size of 0.5 micron. Wet grinding was performed until it became.

Color developer dispersion 1 (A1 solution)
4-Hydroxy-4'-benzyloxydiphenylsulfone (manufactured by NICCA CHEMICAL CO., LTD.)
Product name: BPS-MA3) 6.0 parts Completely saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray, product name: PVA117,
Solid content 10%) 5.0 parts Water 1.5 parts Color developer dispersion 2 (A2 solution)
Ureaurethane compound represented by the chemical formula (Chemical Formula 2) (manufactured by Chemipro Kasei Co., Ltd.,
Product name: UU) 6.0 parts Completely saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray, PVA117) 5.0 parts Water 1.5 parts Color developer dispersion 3 (A3 solution)
4,4'-Dihydroxydiphenylsulfone (manufactured by NICCA CHEMICAL CO., LTD.)
Product name: BPS-P (T)) 6.0 parts Completely saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray, PVA117) 5.0 parts Water 1.5 parts Color developer dispersion 4 (A4 solution)
4-Hydroxy-4'-n-propoxydiphenyl sulfone (manufactured by Mitsubishi Chemical Corporation,
Product name: TOMILAC KN) 6.0 parts Completely saponified polyvinyl alcohol aqueous solution (Kuraray, PVA117) 5.0 parts,
Water 1.5 parts Color developer dispersion 5 (A5 solution)
Diphenyl sulfone cross-linked compound (manufactured by Nippon Soda Co., Ltd., trade name: D90) 6.0 parts Completely saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray Co., Ltd., PVA117) 5.0 parts Water 1.5 parts

Color developer dispersion liquid 6 (A6 liquid)
Urea compound represented by the chemical formula (Chemical Formula 8) (manufactured by IP Corporation,
Product name: SU727) 6.0 parts Completely saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray, PVA117) 5.0 parts Water 1.5 parts

Color developer dispersion 7 (A7 solution)
4-Hydroxyphenyl-4'-phenoxyphenyl sulfone (chemical formula (Chemical formula 9))
6.0 parts Completely saponified polyvinyl alcohol aqueous solution (Kuraray, PVA117) 5.0 parts Water 1.5 parts

Color developer dispersion liquid 8 (A8 liquid)
2,4'-Dihydroxydiphenylsulfone (manufactured by NICCA CHEMICAL CO., LTD.)
Product name: BPS-24C) 6.0 parts Completely saponified polyvinyl alcohol aqueous solution (Kuraray, PVA117) 5.0 parts Water 1.5 parts

Leuco dye dispersion liquid (B liquid)
3-Dibutylamino-6-methyl-7-anilinofluoran (manufactured by Yamamoto Kasei Co., Ltd.,
Product name: ODB-2) 6.0 parts Completely saponified polyvinyl alcohol aqueous solution (Kuraray, PVA117) 5.0 parts Water 1.5 parts Sensitizer dispersion (Liquid C)
1,2-Bis- (3-Methylphenoxy) ethane (manufactured by Sanko Co., Ltd.,
Product name: KS232) 6.0 parts Completely saponified polyvinyl alcohol aqueous solution (Kuraray, PVA117) 5.0 parts Water 1.5 parts

Next, each dispersion was mixed at the following ratio to prepare thermal recording layer coating solutions 1 to 9.
<Heat-sensitive recording layer coating liquid 1>
Color developer dispersion (A1 solution) 18.0 parts Color developer dispersion (A2 solution) 18.0 parts Leuco dye dispersion (B solution) 18.0 parts Sensitizer dispersion (C solution) 9.0 Part Silica dispersion (manufactured by Mizusawa Chemical Co., Ltd., trade name: Mizukasil P-537, solid content 25%)
17.5 parts Completely saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray, PVA117)
25.0 copies

<Heat-sensitive recording layer coating liquid 2>
Color developer dispersion (A1 solution) 36.0 parts Leuco dye dispersion (B solution) 18.0 parts Sensitizer dispersion (C solution) 9.0 parts Silica dispersion (Mizukasil P-, manufactured by Mizusawa Chemical Co., Ltd.) 537) 17.5 parts fully saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray, PVA117)
25.0 copies

<Heat-sensitive recording layer coating liquid 3>
Color developer dispersion (A2 solution) 36.0 parts Leuco dye dispersion (B solution) 18.0 parts Sensitizer dispersion (C solution) 9.0 parts Silica dispersion (Mizukasil P-, manufactured by Mizusawa Chemical Co., Ltd.) 537) 17.5 parts fully saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray, PVA117)
25.0 copies

<Heat-sensitive recording layer coating liquid 4>
Color developer dispersion (A3 solution) 18.0 parts Color developer dispersion (A2 solution) 18.0 parts Leuco dye dispersion (B solution) 18.0 parts Sensitizer dispersion (C solution) 9.0 Part Silica dispersion (Mizukasil P-537, manufactured by Mizusawa Chemical Co., Ltd.) 17.5 parts Completely saponified polyvinyl alcohol aqueous solution (PVA117, manufactured by Kuraray Co., Ltd.)
25.0 copies

<Heat-sensitive recording layer coating liquid 5>
Color developer dispersion (A4 solution) 18.0 parts Color developer dispersion (A2 solution) 18.0 parts Leuco dye dispersion (B solution) 18.0 parts Sensitizer dispersion (C solution) 9.0 Part Silica dispersion (Mizukasil P-537, manufactured by Mizusawa Chemical Co., Ltd.) 17.5 parts Completely saponified polyvinyl alcohol aqueous solution (PVA117, manufactured by Kuraray Co., Ltd.)
25.0 copies

<Heat-sensitive recording layer coating liquid 6>
Color developer dispersion (A5 solution) 18.0 parts Color developer dispersion (A2 solution) 18.0 parts Leuco dye dispersion (B solution) 18.0 parts Sensitizer dispersion (C solution) 9.0 Part Silica dispersion (Mizukasil P-537, manufactured by Mizusawa Chemical Co., Ltd.) 17.5 parts Completely saponified polyvinyl alcohol aqueous solution (PVA117, manufactured by Kuraray Co., Ltd.)
25.0 copies

<Heat-sensitive recording layer coating liquid 7>
Color developer dispersion (A1 solution) 18.0 parts Color developer dispersion (A6 solution) 18.0 parts Leuco dye dispersion (B solution) 18.0 parts Sensitizer dispersion (C solution) 9.0 Part Silica dispersion (Mizukasil P-537, manufactured by Mizusawa Chemical Co., Ltd.) 17.5 parts Completely saponified polyvinyl alcohol aqueous solution (PVA117, manufactured by Kuraray Co., Ltd.)
25.0 copies

<Heat-sensitive recording layer coating liquid 8>
Color developer dispersion (A1 solution) 18.0 parts Color developer dispersion (A2 solution) 18.0 parts Leuco dye dispersion (B solution) 18.0 parts Sensitizer dispersion (C solution) 9.0 Part Silica dispersion (Mizukasil P-537, manufactured by Mizusawa Chemical Co., Ltd.) 7.5 parts Completely saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray, PVA117)
25.0 copies

<Heat-sensitive recording layer coating liquid 9>
Color developer dispersion (A7 solution) 18.0 parts Color developer dispersion (A2 solution) 18.0 parts Leuco dye dispersion (B solution) 18.0 parts Sensitizer dispersion (C solution) 9.0 Part Silica dispersion (Mizukasil P-537, manufactured by Mizusawa Chemical Co., Ltd.) 17.5 parts Completely saponified polyvinyl alcohol aqueous solution (PVA117, manufactured by Kuraray Co., Ltd.)
25.0 copies

Next, a protective layer coating liquid was prepared by mixing the formulations having the following ratios.
<Protective layer coating liquid>
Aluminum hydroxide dispersion (manufactured by Martinsberg)
Product name: Martifin OL, solid content 50%) 9.0 parts carboxy-modified polyvinyl alcohol aqueous solution (manufactured by Kuraray, product name: KL318,
Degree of polymerization: Approx. 1800, degree of saponification: 85-90 mol%, solid content 10%) 30.0 parts Polyamide epichlorohydrin resin (manufactured by Seiko PMC, trade name: WS4030,
Solid content 25%) 4.0 parts Modified polyamine resin (manufactured by Taoka Chemical Co., Ltd., trade name: Smilaise resin SPI-102A,
Solid content 45%) 2.2 parts Zinc stearate (manufactured by Chukyo Yushi Co., Ltd., trade name: Hydrin Z-7-30,
Solid content 30%) 2.0 parts

[Example 1]
After applying the coating liquid 1 for the undercoat layer to one side of the support (high-quality paper with a basis weight of 47 g / m ² ) by the vent blade method so that the coating amount is 10.0 g / m ^{2 in} terms of solid content. , Drying was performed to obtain an undercoat layer coated paper.
On the undercoat layer of this undercoat layer coating paper, the thermal recording layer coating liquid 1 is applied by the rod blade method so that the coating amount is 6.0 g / m ^{2 in} terms of solid content, and then dried and super. A heat-sensitive recorder was prepared by processing with a calendar so that the smoothness was 500 to 1000 seconds.

[Example 2]
Implementation except that the blending amount of the color developer dispersion liquid (A1 liquid) in the thermal recording layer coating liquid 1 was 31.5 parts and the blending amount of the color developer dispersion liquid (A2 liquid) was 4.5 parts. A thermal recorder was prepared in the same manner as in Example 1.
[Example 3]
Implementation except that the blending amount of the color developer dispersion liquid (A1 liquid) in the thermal recording layer coating liquid 1 was 25.5 parts and the blending amount of the color developer dispersion liquid (A2 liquid) was 10.5 parts. A thermal recording body was prepared in the same manner as in Example 1.
[Example 4]
Implemented except that the amount of the color developer dispersion (A1 solution) in the thermal recording layer coating solution 1 was 4.5 parts and the amount of the color developer dispersion (A2 solution) was 31.5 parts. A thermal recorder was prepared in the same manner as in Example 1.

[Example 5]
Instead of the undercoat layer coating liquid 1, the amount of calcined kaolin in the undercoat layer coating liquid 2 was changed to 80.0 parts, the amount of plastic hollow particles was changed to 74.0 parts, and the amount of water was 81.0 parts. A heat-sensitive recording body was produced in the same manner as in Example 1 except that the coating liquid was used instead of.
[Example 6]
A heat-sensitive recorder was produced in the same manner as in Example 1 except that the undercoat layer coating liquid 2 was used instead of the undercoat layer coating liquid 1.
[Example 7]
Except for using a coating liquid in which the amount of calcined kaolin in the undercoat layer coating liquid 2 was changed to 0 parts and the amount of plastic hollow particles was changed to 370.0 parts instead of the undercoat layer coating liquid 1. , A heat-sensitive recording body was produced in the same manner as in Example 1.

[Example 8]
After applying the coating liquid 1 for the undercoat layer to one side of the support (high-quality paper with a basis weight of 47 g / m ² ) by the vent blade method so that the coating amount is 10.0 g / m ^{2 in} terms of solid content. , Drying was performed to obtain an undercoat layer coated paper.
On the undercoat layer of this undercoat layer coating paper, the thermal recording layer coating liquid 8 is applied by the rod blade method so that the coating amount is 6.0 g / m ^{2 in} terms of solid content, and then dried and super. A heat-sensitive recording layer coated paper was prepared by treating with a calendar so that the smoothness was 500 to 1000 seconds.
Next, the protective layer coating liquid is applied onto the thermal recording layer of the thermal recording layer coating paper by the rod blade method so that the coating amount is 2.0 g / m ^{2 in} terms of solid content, and then dried. To prepare a thermal recording body.
[Example 9]
Implementation except that the blending amount of the color developer dispersion liquid (A1 liquid) in the thermal recording layer coating liquid 8 was 31.5 parts and the blending amount of the color developer dispersion liquid (A2 liquid) was 4.5 parts. A thermal recorder was prepared in the same manner as in Example 8.

[Comparative Example 1]
A heat-sensitive recording body was produced in the same manner as in Example 1 except that the heat-sensitive recording layer coating liquid 2 was used instead of the heat-sensitive recording layer coating liquid 1.
[Comparative Example 2]
A heat-sensitive recording body was produced in the same manner as in Example 1 except that the heat-sensitive recording layer coating liquid 3 was used instead of the heat-sensitive recording layer coating liquid 1.
[Comparative Example 3]
A heat-sensitive recording body was produced in the same manner as in Example 1 except that the heat-sensitive recording layer coating liquid 4 was used instead of the heat-sensitive recording layer coating liquid 1.
[Comparative Example 4]
A heat-sensitive recording body was produced in the same manner as in Example 1 except that the heat-sensitive recording layer coating liquid 5 was used instead of the heat-sensitive recording layer coating liquid 1.

[Comparative Example 5]
A heat-sensitive recording body was produced in the same manner as in Example 1 except that the heat-sensitive recording layer coating liquid 6 was used instead of the heat-sensitive recording layer coating liquid 1.
[Comparative Example 6]
A heat-sensitive recording body was produced in the same manner as in Example 1 except that the heat-sensitive recording layer coating liquid 7 was used instead of the heat-sensitive recording layer coating liquid 1.
[Comparative Example 7]
A heat-sensitive recording body was produced in the same manner as in Example 1 except that the heat-sensitive recording layer coating liquid 9 was used instead of the heat-sensitive recording layer coating liquid 1.

[Comparative Example 8]
A heat-sensitive recording body was prepared in the same manner as in Example 1 except that the developer dispersion liquid (A2 liquid) in the heat-sensitive recording layer coating liquid 1 was replaced with the color developer dispersion liquid (A3 liquid). did.
[Comparative Example 9]
A heat-sensitive recording body was produced in the same manner as in Example 1 except that the color-developing agent dispersion (A2 solution) in the heat-sensitive recording layer coating solution 1 was replaced with the color-developing agent dispersion (A8). did.
[Comparative Example 10]
A heat-sensitive recording body was produced in the same manner as in Example 1 except that the color-developing agent dispersion (A2 solution) in the heat-sensitive recording layer coating solution 1 was replaced with the color-developing agent dispersion (A4 solution). did.

[Comparative Example 11]
A heat-sensitive recording body was prepared in the same manner as in Example 6 except that the developer dispersion liquid (A1 liquid) in the heat-sensitive recording layer coating liquid 1 was replaced with the color-developing agent dispersion liquid (A3 liquid). did.
[Comparative Example 12]
A heat-sensitive recording body was prepared in the same manner as in Example 6 except that the developer dispersion liquid (A1 liquid) in the heat-sensitive recording layer coating liquid 1 was replaced with the color-developing agent dispersion liquid (A4 liquid). did.
[Comparative Example 13]
A heat-sensitive recording body was prepared in the same manner as in Example 6 except that the developer dispersion liquid (A2 liquid) in the heat-sensitive recording layer coating liquid 1 was replaced with the color developer dispersion liquid (A3 liquid). did.
[Comparative Example 14]
A heat-sensitive recording body was prepared in the same manner as in Example 6 except that the color-developing agent dispersion (A2 solution) in the heat-sensitive recording layer coating solution 1 was replaced with the color-developing agent dispersion (A4 solution). did.

The prepared heat-sensitive recorder was evaluated as follows.
<Color development performance (print density)>
A checkered pattern was used for the manufactured heat-sensitive recorder using TH-PMD manufactured by Okura Electric Co., Ltd. (with a heat-sensitive recording paper printing tester and a thermal head manufactured by Kyocera) at an applied energy of 0.35 mJ / dot and a printing speed of 50 mm / sec. Was printed.
The print density of the print section was measured with a Macbeth densitometer (RD-914, using an amber filter), and the color development performance (print density) was evaluated.

<Heat resistance of blank paper>
The prepared heat-sensitive recorder was treated under environmental conditions of 80 ° C. or 90 ° C. for 24 hours, and then allowed to stand for 3 hours under environmental conditions of 23 ° C. × 50% RH.
The density of the non-printed part (blank paper part) is measured with a Macbeth densitometer (RD-914, using amber filter), the ground color development value is calculated from the difference between the values before and after processing, and the non-printed part (blank paper part) is calculated according to the following criteria. The heat resistance of part) was evaluated.
Ground color development value = (Density of non-printed area after processing)-(Density of non-printed area before processing)
Excellent: Ground color development value is less than 0.1 Good: Ground color development value is 0.1 or more and less than 0.3 Possible: Ground color development value is 0.3 or more and less than 0.5 Impossible: Ground color development value is 0. 5 or more

<Barcode reading suitability>
After placing the prepared heat-sensitive recorder under the following environmental conditions (1) to (3), a printing level of +10 and a printing speed of 15.2 cm / sec (6 inches / sec) were used using a Zebra label printer 140XiIII. A barcode (CODE39) was printed.
(1) The mixture was allowed to stand for 3 hours under 23 ° C. × 50% RH environmental conditions.
(2) After being left under 80 ° C. environmental conditions for 24 hours, it was allowed to stand for 3 hours under 23 ° C. × 50% RH environmental conditions.
(3) After being left under 50 ° C. × 90% RH environmental conditions for 24 hours, it was allowed to stand under 23 ° C. × 50% RH environmental conditions for 3 hours.

Next, the printed barcode was subjected to a reading test with a barcode verification machine (Honeywell, QCPC600, light source 640 nm) to evaluate the barcode reading suitability. The evaluation results are shown in the ANSI standard symbol grade.
Symbol grade: The barcode is divided into 10 parts perpendicular to the bar, a reading test is performed once at each location, and the average value is evaluated on a 5-point scale of (excellent) A, B, C, D, and F (poor). It is represented by.

The evaluation results are shown in Table 1.

From Table 1, an undercoat layer is provided on the support, and the heat-sensitive recording layer provided on the undercoat layer is represented by a sulfone compound represented by the general formula (Chemical formula 1) and a general formula (Chemical formula 2) as a color developer. It can be seen that when the urea urethane compound is contained in a specific ratio, the color development performance in a harsh environment, particularly the barcode reading suitability and the heat resistance of the blank sheet portion are improved in a well-balanced manner (Examples 1 to 1). 4,8,9).
Furthermore, it can be seen that when the undercoat layer contains a specific amount of hollow plastic particles, the heat resistance of the blank paper portion under a harsh environment (particularly, the heat resistance of the blank paper portion at 90 ° C.) is further improved. (Examples 6 and 7).

Claims (7)

A heat-sensitive recorder in which an undercoat layer is provided on a support and a heat-sensitive recording layer containing a colorless or light-colored electron-donating leuco dye and an electron-accepting color developer is provided on the undercoat layer. The recording layer contains a sulfone compound represented by the following general formula (Chemical Formula 3 ) and a urea urethane compound represented by the following general formula (Chemical Formula 2) as an electron-accepting color developer, and the general formula (Chemical Formula 3 ). A heat-sensitive recorder containing 0.01 to 12.0 parts by weight of a urea urethane compound represented by the general formula (Chemical Formula 2) with respect to 1 part by weight of the sulfone compound represented by.

(In the formula , R ² and R ³ each independently represent a hydrogen atom, an alkyl group or an alkoxy group having 1 to 6 carbon atoms, and m is an integer of 1 or 2. )

The heat-sensitive recorder according to claim 1, wherein the undercoat layer contains plastic hollow particles as a pigment. The heat-sensitive recorder according to claim 2, wherein the undercoat layer contains 45% by weight or more of hollow plastic particles with respect to the total amount (solid content) of the pigment. Claim that the urea urethane compound represented by the general formula (Chemical Formula 2) is contained in a ratio of 0.01 to 1.1 parts by weight with respect to 1 part by weight of the sulfone compound represented by the general formula (Chemical Formula 3 ). The heat-sensitive recorder according to any one of 1 to 3. The heat-sensitive recorder according to any one of claims 1 to 4 , wherein at least one of R ² and R ³ is a hydrogen atom. The heat-sensitive recorder according to any one of claims 1 to 5 , wherein m is 1. The heat-sensitive recorder according to any one of claims 1 to 4, wherein the sulfone compound is 4-hydroxy-4'-benzyloxydiphenyl sulfone.