JP2018094915A - Thermosensitive recording body and thermosensitive recording tag - Google Patents

Abstract

The present invention provides a thermal recording medium and a thermal recording tag that are excellent in color development performance under severe environments, in particular, barcode reading ability. A heat-sensitive recording medium comprising a heat-sensitive recording layer containing a colorless or light-colored electron-donating leuco dye and an electron-accepting developer on a support, and a protective layer provided on the heat-sensitive recording layer, and a heat-sensitive recording medium. In the recording tag, the heat-sensitive recording layer contains a specific sulfone compound and a specific urea urethane compound as an electron-accepting developer in a specific ratio. This protective layer preferably contains carboxy-modified polyvinyl alcohol or non-core shell acrylic resin as a binder. The support is preferably a film or synthetic paper. [Selection figure] None

Description

  The present invention utilizes a coloring reaction between a colorless or light-colored electron-donating leuco dye (hereinafter also referred to as “leuco dye”) and an electron-accepting developer (hereinafter also referred to as “developer”). The present invention relates to a thermosensitive recording medium and a thermosensitive recording tag that have good color development performance in a harsh environment, in particular, good bar code readability.

In general, a thermal recording material is usually a colorless or light leuco dye and a developer such as a phenolic compound, each of which is ground and dispersed into fine particles, and then mixed together to form a binder, a filler, a sensitivity improver, A coating solution obtained by adding a lubricant and other auxiliary agents is applied to a support such as paper, synthetic paper, film, plastic, etc., such as thermal head, hot stamp, thermal pen, laser beam, etc. Color is generated by an instantaneous chemical reaction by heating, and a recorded image is obtained. Thermosensitive recording media are widely used as recording media for facsimiles, computer terminal printers, automatic ticket vending machines, recorders for measurement, receipts for supermarkets and convenience stores, and the like.
In recent years, thermal recording media have been used for various types of tickets, receipts, labels and tags, bank ATMs, gas and electricity meter readings, and cash vouchers, etc. Therefore, it is necessary to preserve the image area and the blank paper area under an environment such as a high temperature in a car in midsummer.
As a method for improving the storage stability of the image area, it is generally known to provide a protective layer on the thermosensitive recording layer. However, when a protective layer is provided on the thermal recording medium, the protective layer absorbs the thermal energy given from the thermal head, so the color development performance, that is, the color development sensitivity and image quality, particularly the barcode reading ability is inferior. There is. In particular, if the color development sensitivity decreases and the difference in contrast between the print area and the white paper area becomes small, when the barcode is printed, it cannot be read by a reader even if it can be visually observed. There was a problem that aptitude was insufficient.
On the other hand, a thermal recording material (Patent Documents 1 and 2) in which the storage stability of the image area is improved by using a specific developer and stabilizer in combination, or a specific sensitizer and stabilizer are used in combination. Discloses a heat-sensitive recording material (Patent Document 3) that improves the storage stability of the image area.
Furthermore, a thermal recording material (Patent Document 4), a urea compound or a urea urethane compound, and a BPS developer that have improved color development performance and storability of the image area by using two specific types of developers in combination. Thermal recording materials (Patent Documents 5 to 8) are disclosed which have improved storage stability by using a combination of two kinds of color developers.

JP2003-154760 JP 2001-347757 A International Publication WO2004 / 002748 JP 2006-264255 A JP 2002-178646 A JP 2002-178645 A JP2000-143611 International Publication WO00 / 014058

When the heat-sensitive recording material is used for a use in a severe environment such as the above-described label use or ticket use whose use has been expanding in recent years, the storability of the image portion and the white paper portion is insufficient.
Furthermore, the heat-sensitive recording material (Patent Document 4) or the like using a combination of the above two specific types of color developer is used for applications used in harsh environments because the heat resistance of the white paper portion is inferior. The white paper portion is colored, and the barcode reading ability is insufficient.
In addition, in a heat-sensitive recording material (Patent Documents 5 to 8) using a combination of two types of developer such as a urea compound or urea urethane compound and a BPS developer, depending on the compound and developer used for the combination. The performance is very different.
SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive recording material that has good color development performance in a harsh environment, in particular, good barcode readability. In the present invention, the harsh environment refers to, for example, a high temperature and / or high humidity condition, the high temperature refers to, for example, 70 ° C. or higher, and the high humidity refers to, for example, 80% RH or higher.

（式中、Ｒ１は水素原子又は水酸基、Ｒ２及びＲ３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。）

また本発明は、前記感熱記録体の支持体の感熱記録層とは反対側に、ライナーレス粘着剤層を設けた感熱記録タグである。 As a result of intensive studies, the present inventors have found that the above-mentioned problems can be solved by including two specific types of color developer in a specific ratio in the thermal recording layer and further providing a protective layer on the thermal recording layer. The invention has been completed.
That is, the present invention provides a heat-sensitive recording material comprising a heat-sensitive recording layer containing a colorless or light-colored electron-donating leuco dye and an electron-accepting developer on a support, and a protective layer provided on the heat-sensitive recording layer. The heat-sensitive recording layer contains a sulfone compound represented by the following general formula (Chemical Formula 1) and a urea urethane compound represented by the following General Formula (Chemical Formula 2) as an electron-accepting developer, The heat-sensitive recording material contains 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 the general formula (Chemical Formula 1).

(In the formula, R1 represents a hydrogen atom or a hydroxyl group, R2 and R3 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an alkoxy group, and m represents an integer of 1 to 3).

The present invention also relates to a thermal recording tag in which a linerless pressure-sensitive adhesive layer is provided on the opposite side of the support of the thermal recording body to the thermal recording layer.

  According to the present invention, it is possible to provide a heat-sensitive recording medium and a heat-sensitive recording tag that have good color development performance, particularly barcode readability, even under harsh environments.

  The heat-sensitive recording material of the present invention is provided with a heat-sensitive recording layer containing a colorless or light leuco dye and a developer on a support, and the heat-sensitive recording layer contains a specific sulfone compound and a specific color developer. These urea urethane compounds are contained in a specific ratio.

Examples of the support used in the present invention include paper, synthetic paper, film and plastic.
The support can be appropriately selected from these conventionally known supports in accordance with the desired quality of the thermal recording material, and is not particularly limited. Moreover, you may use the composite sheet which combined these as a support body.
The film used in the present invention is formed from a polymer raw material in a thin film shape, tough and firm, and particularly excellent in fracture resistance, water resistance, chemical resistance, etc., so labels for food, daily necessities, etc. It is suitable for sealing applications.
Specifically, ionomer film (IO), polyethylene film (PE), polyvinyl chloride film (PVC), polyvinylidene chloride film (PVDC), polyvinylidene fluoride film (PVDF), polyvinyl alcohol film (PVA), polypropylene film (PP), polyester film (PE), polyethylene terephthalate film (PET), polyethylene naphthalate film (PEN), polycarbonate film (PC), polystyrene film (PS), polyacrylonitrile film (PAN), ethylene vinyl acetate copolymer Combined film (EVA), ethylene vinyl alcohol copolymer film (EMAA), nylon film (NY), polyamide film (PA), triacetyl cellulose fill (TAC), norbornene film (NB), cycloolefin films, and composite films that combine these films can be exemplified.
Synthetic paper used in the present invention is manufactured using synthetic resin as a main raw material, and has the basic characteristics of paper, and has excellent rupture resistance, water resistance, chemical resistance, etc., like a film. It is suitable for labels and seal applications. Furthermore, since it is supple and flexible as compared with a film, it is particularly suitable for a curved label such as a bottle or a food container, or a label used on a soft packaging material such as a bag.

この式中、Ｒ１は水素原子又は水酸基、好ましくは水酸基である。
またＲ２及びＲ３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、Ｒ２及びＲ３の少なくとも一方が水素原子であり、さらに好ましくはＲ２及びＲ３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 (Formula 1).

In this formula, R1 is a hydrogen atom or a hydroxyl group, preferably a hydroxyl group.
R2 and R3 are each independently a hydrogen atom, an alkyl group or an alkoxy group having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. More preferably, at least one of R2 and R3 is a hydrogen atom, and more preferably both R2 and R3 are hydrogen atoms.
m is an integer of 1 to 3, preferably 1 or 2, and 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, 1,2-trimethylpropyl group, 1,2,2-trimethylpropyl group, 1-ethyl-1-methylpropyl group, 1-ethyl Examples include linear or branched alkyl groups having 1 to 6 carbon atoms such as ru-2-methylpropyl group, preferably alkyl groups having 1 to 3 carbon atoms, that is, methyl group, ethyl group, propyl group, isopropyl group. It is a group.
Examples of the alkoxy group include 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 pentyloxy group, neopentyloxy group, 2-methylbutoxy group, 1,2-dimethylpropoxy group, 1-ethylpropoxy group, hexyloxy group. And preferably a methoxy group, an ethoxy group, a propoxy group, or an isopropoxy group.

この式中、Ｒ２、Ｒ３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。

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

In this formula, R2, R3 and m are defined in the same manner as described above.
More preferred sulfone compounds used in the present invention include 4-hydroxy-4′-benzyloxydiphenylsulfone, 4-hydroxy-4′-phenethyloxydiphenylsulfone, 4-hydroxy-4 ′-(3-phenylpropoxy) diphenylsulfone. 4-hydroxy-4′-benzyloxydiphenyl sulfone (the following formula) is most preferable.

The urea urethane compound used in the present invention is represented by the following general formula (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 developer, the thermal formula 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 high electronegativity, it exhibits basicity when heated and melted.
In a basic environment, the urea urethane compound is likely to be an enol type, and in particular, the reaction efficiency between the urea urethane compound and the leuco dye is increased, and an electron transfer complex is easily generated and the reverse reaction is less likely to occur. As a result, it is presumed that the resulting heat-sensitive recording material has good color development performance, particularly barcode readability, and is excellent in heat resistance of the blank paper portion.

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

In the heat-sensitive recording layer of the present invention, the urea urethane compound represented by the general formula (Chemical Formula 2) is used as a developer in an amount of 0.01 to 12% 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 compound, preferably 0.05 parts by weight or more, more preferably 0.1 parts by weight or more, with respect to 1 part by weight of the sulfone compound. In addition, the thermosensitive recording layer contains a urea urethane 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, relative to 1 part by weight of the sulfone compound. It is particularly preferably 0.5 parts by weight or less, 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 thermosensitive recording medium in a harsh environment, In particular, the bar code readability is the best (see the examples described later). If the urea urethane compound represented by the general formula (Chemical Formula 2) is less than 0.01 part by weight with respect to 1 part by weight of the sulfone compound represented by the general formula (Chemical Formula 1), the barcode readability is sufficient. It may not be. In addition, when 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 white paper part tends to decrease.

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

  Examples of the 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) used in the present invention include activated clay, attapulgite, colloidal silica, Inorganic acidic substances such as aluminum silicate, 4,4′-isopropylidenediphenol, 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-propoxydiphenylsulfone 4-hydroxy-4′-allyloxydiphenylsulfone, bis (3-allyl-4-hydroxyphenyl) sulfone, 4-hydroxy-4′-methyldiphenylsulfone, 3,4-dihydroxyphenyl-4′-methylphenylsulfone, 1- [4- (4-hydroxyphenylsulfonyl) phenoxy] -4- [4- (4-isopropoxyphenylsulfonyl) phenoxy] butane, a phenol condensation composition described in JP-A-2003-154760, JP-A-8- 59603 aminobenzenesulfonamide derivative, bis (4-hydroxyphenylthioethoxy) methane, 1,5-di (4-hydroxyphenylthio) -3-oxapentane, butyl bis (p-hydroxyphenyl) acetate, Methyl bis (p-hydroxyphenyl) acetate, , 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 diphenylsulfone cross-linking compounds described in WO 97/16420, compounds described in WO 02/081229 or JP 2002-301873, N, N′-di-m-chlorophenylthiourea, etc. Thiourea compound, p-chlorobenzoic acid, stearyl gallate, bis [4- (n-octyloxycarbonylamino) B) Zinc salicylate] dihydrate, 4- [2- (p-methoxyphenoxy) ethyloxy] salicylic acid, 4- [3- (p-tolylsulfonyl) propyloxy] salicylic acid, 5- [p- (2-p -Methoxyphenoxyethoxy) cumyl] aromatic carboxylic acids of salicylic acid and salts of these aromatic carboxylic acids with polyvalent metal salts such as zinc, magnesium, aluminum, calcium, titanium, manganese, tin, nickel, and thiocyan Examples thereof include an antipyrine complex of zinc acid, and a complex zinc salt of terephthalaldehyde acid and other aromatic carboxylic acid. These developers can 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 API Corporation. Yes, the phenol condensation composition described in JP-A No. 2003-154760 is available, for example, under the trade name JKY-224 manufactured by API Corporation, and is a diphenylsulfone cross-linking compound described in International Publication No. WO 97/16420 Is available under the trade name D-90 manufactured by Nippon Soda Co., Ltd. Moreover, the compound as described in WO02 / 081229 etc. is available as Nippon Soda Co., Ltd. brand name NKK-395 and D-100. In addition, a metal chelate color-developing component such as a higher fatty acid metal double salt and a polyvalent hydroxyaromatic compound described in JP-A-10-258577 can also be contained.

  Next, various materials used in the heat-sensitive recording layer of the heat-sensitive recording material of the present invention are exemplified, but a binder, a crosslinking agent, a pigment, and the like are provided as necessary as long as the desired effects on the above-described problems are not inhibited. It can also be used for coating layers other than the heat-sensitive recording layer, that is, protective layers and undercoat layers.

  As the leuco dye used in the present invention, any known leuco dyes in the field of conventional pressure-sensitive or thermal recording paper can be used, and are not particularly limited, but include triphenylmethane compounds, fluoran compounds, fluorenes. Of these, divinyl compounds and divinyl compounds are preferred. 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, 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-di Tilamino-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-ethoxy Ethyl-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-diethylamino-benzo [c] fluorane, 3-dibutylamino-6-methyl-fluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7- (o, p-dimethylanilino) fluorane, 3-dibutylamino-6-methyl-7- ( o-chloroanilino) fluorane, 3-dibutylamino-6-methyl-7- (p-chloroanilino) fluorane, 3-dibutylamino-6-methyl-7- (o-fluoroanilino) fluorane, 3-dibutylamino-6 -Methyl-7- (m-trifluoromethylanilino) fluorane, 3-dibutylamino- 6-methyl-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-chloro) Nilino) 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-toludino) -6-methyl-7-ani Linofluorane, 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluorane, 3- (N-ethyl-N-isoamylamino) -6-chloro-7-a Linofluorane, 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluorane, 3- (N-ethyl-N-isobutylamino) -6-methyl-7-anilinofur Oran, 3- (N-ethyl-N-ethoxypropylamino) -6-methyl-7-anilinofluorane, 3-cyclohexylamino-6-chlorofluorane, 2- (4-oxahexyl) -3-dimethyl Amino-6-methyl-7-anilinofluorane, 2- (4-oxahexyl) -3-diethylamino-6-methyl-7-anilinofluorane, 2- (4-oxahexyl) -3-dipropyl Amino-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) 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-phenylamino) Nophenyl) aminoanilinofluorane, 3-methyl-6-p- (p-dimethylaminophenyl) aminoanilinofluorane, 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)- 4-azaphthalide, 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide, 3,6-bis (diethylamino) fluorane-γ- (3′-nitro) anilinolactam, 3,6 -Bis (diethylamino) fluorane-γ- (4′-nitro) anilinolactam, 1,1-bis- [2 ′, 2 ′, 2 ″, 2 ″ -tetrakis- (p-dimethylamino) Enyl) -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 the sensitizer include fatty acid amides such as stearamide and palmitic acid amide, ethylene bisamide, montanic acid wax, polyethylene wax, 1,2-bis- (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-me Tilphenoxymethyl) biphenyl, 4,4′-ethylenedioxy-bis-benzoic acid dibenzyl ester, dibenzoyloxymethane, 1,2-di (3-methylphenoxy) 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, and silica, depending on the required quality. It can also be used together.

The binder used in the present invention includes 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 copolymerizable with (meth) acrylic acid Acrylic resin (excluding olefins), hydroxyethyl cellulose, methyl cellulose, ethyl cellulose, carbo Cellulose derivatives such as methylcellulose, ethylcellulose, acetylcellulose, starches such as oxidized starch, etherified starch, esterified starch, styrene-maleic anhydride copolymer, styrene-butadiene copolymer, casein, arabic rubber, polyvinyl chloride, Examples thereof include polyvinyl acetate, polyacrylamide, polyacrylic ester, polyvinyl butyral, polystyrose and copolymers thereof, polyamide resin, silicone resin, petroleum resin, terpene resin, ketone resin, coumarone resin and the like. 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.
The binder content (solid content) in the heat-sensitive recording layer is preferably about 5 to 25% by weight.

  Examples of the crosslinking agent used in the present invention include zirconium chloride, zirconium sulfate, zirconium nitrate, zirconium acetate, zirconium carbonate, zirconium stearate, zirconium octoate, zirconium silicate, zirconium oxynitrate, zirconium carbonate potassium salt, zirconium carbonate ammonium salt and the like. Zirconium compounds, glyoxal, glutaraldehyde, 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 include sodium persulfate, ferric chloride, magnesium chloride, borax, boric acid, alum, ammonium chloride and the like.

  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-tert-butyl-3-methylphenol), 2 as a stabilizer for improving the oil resistance and the like of the image area as long as the desired effect on the above problems is not impaired. 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 can also be added. In addition, benzophenone and triazole ultraviolet absorbers, dispersants, antifoaming agents, antioxidants, fluorescent dyes, and the like can be used.

  The types and amounts of the leuco dye, developer, sensitizer, and other various 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 developer, 0.1 to 10 parts by weight of sensitizer, 0.5 to 20 parts by weight of pigment, and 0.01 to 10 parts by weight of stabilizer for 1 part by weight of leuco dye. Parts and other components of about 0.01 to 10 parts by weight.

  In the present invention, the leuco dye, the developer, and the material to be added as necessary are finely divided to a particle size of several microns or less by a pulverizer such as a ball mill, an attritor, or a sand glider, or an appropriate emulsifying device, and a binder. Depending on the purpose, various additive materials are added to obtain 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 heat-sensitive recording material of the present invention further has a protective layer on the heat-sensitive recording layer.
This protective layer mainly comprises a binder and a pigment, and a crosslinking agent may be further added thereto.
As the binder, binders that can be used in the above-mentioned heat-sensitive recording layer can be used as appropriate, but carboxy-modified polyvinyl alcohol and non-core shell acrylic resins are preferable. These binders may be used alone or in combination of two or more.
Moreover, as a crosslinking agent, although the crosslinking agent which can be used for the above-mentioned thermosensitive recording layer can be used suitably, epichlorohydrin type resin and polyamine / polyamide type resin (what is contained in epichlorohydrin type resin is used. Is preferred).
More preferably, the protective layer contains an epichlorohydrin resin and a polyamine / polyamide resin together with carboxy-modified polyvinyl alcohol, thereby further improving the color development performance.

  This carboxy-modified polyvinyl alcohol is, for example, a reaction product of polyvinyl alcohol and a polycarboxylic acid such as fumaric acid, phthalic anhydride, melittic anhydride, itaconic anhydride, or an esterified product of these reactants, and vinyl acetate. It is obtained as a saponified product of a copolymer with an ethylenically unsaturated dicarboxylic acid such as maleic acid, fumaric acid, itaconic acid, crotonic acid, acrylic acid or methacrylic acid. Specific examples of the production method include the method exemplified in JP-A-53-91995. Moreover, it is preferable that the saponification degree of carboxy modified polyvinyl alcohol is 72-100 mol%, and a polymerization degree is 500-2400, More preferably, it is 1000-2000.

The glass transition point (Tg) of this non-core-shell type acrylic resin is preferably 95 ° C. or lower, more preferably higher than 50 ° C. 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 preferable that it is -10 weight part. (Meth) acrylic acid is alkali-soluble and has the property of making a non-core shell acrylic resin a water-soluble resin by the addition of a neutralizing agent. By changing the non-core-shell type acrylic resin to a water-soluble resin, especially when the protective layer contains a pigment, the binding property to the pigment is remarkably improved, and the protective layer has excellent strength even when containing a large amount of pigment. Can be formed. Examples of components copolymerizable with (meth) acrylic acid include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, By alkyl acrylate resins such as pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, and epoxy resins, silicone resins, styrene or derivatives thereof Modified alkyl acrylate resins such as the above-mentioned alkyl acrylate resins, (meth) acrylonitrile, acrylate esters, and hydroxyalkyl acrylate esters can be exemplified, but in particular, (meth) acrylonitrile and / or methyl methacrylate is blended. Is preferred. (Meth) acrylonitrile is preferably blended in an amount of 15 to 70 parts per 100 parts of the non-core shell acrylic resin. Moreover, it is preferable that methyl methacrylate contains 20-80 parts in 100 parts of non-core-shell type acrylic resins. When (meth) acrylonitrile and methyl methacrylate are included, (meth) acrylonitrile is blended in 15 to 18 parts in 100 parts of non-core-shell acrylic resin, and methyl methacrylate is blended in 20 to 80 parts in 100 parts of non-core-shell acrylic resin. It is preferable.

  This epichlorohydrin resin is a resin characterized by containing an epoxy group in the molecule, and examples thereof include polyamide epichlorohydrin resin, polyamine epichlorohydrin resin, These 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. Furthermore, since the water resistance is good, the degree of cationization and the molecular weight are preferably a cationization degree of 5 meq / g · Solid (measured value at pH 7) and a molecular weight of 500,000 or more. Specific examples of the epichlorohydrin resin include Sumire Resin 650 (30), Sumire Resin 675A, Sumire Resin 6615 (manufactured by Sumitomo Chemical Co., Ltd.), WS4002, WS4020, WS4024, WS4030, WS4046, WS4010, CP8970 (manufactured by Starlight PMC) and the like.

  This polyamine / polyamide resin does not have an epoxy group in the molecule. For example, it is a polyamide urea resin, polyalkylene polyamine resin, polyalkylene polyamide resin, polyamine polyurea resin, modified polyamine resin, modified polyamide resin, polyalkylene polyamine. Examples include urea formalin resin, polyalkylene polyamine polyamide polyurea resin, and the like, and these can be used alone or in combination. Specific examples of the polyamine / polyamide resin include Sumire Resin 302 (manufactured by Sumitomo Chemical: polyamine polyurea resin), Sumire Resin 712 (manufactured by Sumitomo Chemical: polyamine polyurea resin), and Sumire Resin 703 (Sumitomo Chemical). Manufactured by: Polyamine Polyurea Resin), Sumire Resin 636 (Sumitomo Chemical Co .: Polyamine Polyurea Resin), Sumire Resin SPI-100 (Sumitomo Chemical: Modified Polyamine Resin), Sumire Resin SPI-102A (Sumitomo) Chemical Company: Modified Polyamine Resin), Sumire Resin SPI-106N (Sumitomo Chemical: Modified Polyamide Resin), Sumire Resin SPI-203 (50) (Sumitomo Chemical), Sumire Resin SPI-198 (Sumitomo) Chemical Co., Ltd.), Printive A-700, Printive A-600 (or more Asahi Kasei Co., Ltd.), PA6500, PA6504, PA6634, PA6638, PA6640, PA6664, PA6646, PA6654, PA6702, PA6704 (above, manufactured by Seiko PMC: polyalkylene polyamine polyamide polyurea resin), CP8994 (produced by Seiko PMC: polyethyleneimine) Resin). Although there is no particular limitation, a polyamine resin (polyalkylene polyamine resin, polyamine polyurea resin, modified polyamine resin, polyalkylene polyamine urea formalin resin, polyalkylene polyamine polyamide polyurea resin) is used because the printing density is good. It is preferable.

  The content in the case of using epichlorohydrin resin and polyamine / polyamide resin together with carboxy-modified polyvinyl alcohol in the protective layer 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 in the protective layer, pigments usable in the above-mentioned heat-sensitive recording layer can be used as appropriate, 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, and more preferably about 20 to 80% by weight. 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.
As necessary, the coating liquid for the protective layer includes a crosslinking agent, a lubricant, a stabilizer, an ultraviolet absorber, a dispersant, an antifoaming agent, an antioxidant, a fluorescent dye, and the like that can be used in the above-mentioned heat-sensitive recording layer. You may mix | blend various adjuvants suitably.

In the heat-sensitive recording material of the present invention, an undercoat layer may be provided between the support and the heat-sensitive recording layer.
This undercoat layer mainly comprises a binder and a pigment.
As the binder used for the undercoat layer, binders usable 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 conventionally, specific examples include calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, magnesium hydroxide, kaolin, calcined kaolin, clay, Inorganic pigments such as talc and organic pigments such as plastic hollow particles can be used, but it is preferable to use calcined kaolin as the inorganic pigment and plastic hollow particles as the organic pigment. These pigments may be used alone or in combination of two or more.
The hollow plastic particles of the present invention are fine hollow particles that are already in a foamed state and contain a thermoplastic resin as a shell and contain air or other gas inside. Examples of the thermoplastic resin include polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyacrylic acid ester, polyacrylonitrile, polybutadiene, and copolymers thereof. In particular, styrene resins such as polystyrene, acrylic resins such as polyacrylic acid esters and polyacrylonitrile, copolymers thereof, or copolymer resins mainly composed of polyvinylidene chloride and polyacrylonitrile are preferable. Such organic hollow particles are available as SX8782 manufactured by JSR, MH5055, MH8108A manufactured by Nippon Zeon, Ropaque HP-91 manufactured by Rohm & Haas Japan, Microsphere manufactured by Matsumoto Yushi.
The volume hollow ratio of the plastic hollow particles of the present invention is preferably about 40 to 95%. By setting the volumetric hollow ratio to 40% or more, it is possible to improve heat insulation and further improve the color development performance. On the other hand, by setting it to 95% or less, it becomes easy to increase the shell strength of the hollow particles to effectively maintain the hollow state and to obtain an undercoat layer having a good surface strength. Here, the volume hollowness is a value obtained by (d3 / D3) × 100. In the formula, d represents the inner diameter of the organic hollow particles, and D represents 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 with respect to 100 parts by weight of the total solid content.
When the undercoat layer contains calcined kaolin and plastic hollow particles, the content ratio of the plastic hollow particles is preferably 10 to 1000 parts by weight, more preferably 20 to 500 parts by weight, and more preferably 50 to 150 parts by weight with respect to 100 parts by weight of calcined kaolin. Part by weight is more preferred.
Various additives such as a dispersant, a plasticizer, a pH adjuster, an antifoaming agent, a water retention agent, an antiseptic, a coloring dye, and an ultraviolet ray inhibitor may be appropriately blended in the undercoat layer coating liquid as necessary. Good.

In the present invention, the means for coating the heat-sensitive recording layer and the coating layer other than the heat-sensitive recording layer is not particularly limited, and 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 coating layer other than the heat-sensitive recording layer and the heat-sensitive recording layer is determined according to the required performance and recording suitability, and is not particularly limited, but the general coating amount of the heat-sensitive recording layer is solid. The minute is about 2 to 12 g / m2. The general coating amount of the undercoat layer is about 1 to 15 g / m 2 in terms of solid content, and the general coating amount of the protective layer is about 1 to 5 g / m 2 in terms of solid content. In this invention, it is preferable that the coating amount of a protective layer shall be 1-3 g / m <2> by solid content.
Further, various known techniques in the heat-sensitive recording material field can be added as appropriate, such as applying a smoothing process such as supercalendering after coating each layer.

The heat-sensitive recording tag of the present invention has a linerless pressure-sensitive adhesive layer provided on the opposite side of the support of the heat-sensitive recording body from the heat-sensitive recording layer. This linerless pressure-sensitive adhesive layer refers to a pressure-sensitive adhesive layer that does not require the use of a release paper (liner). It does not exhibit pressure-sensitive adhesive properties at room temperature or pressure, and is pressure-sensitive by heating or pressure. Demonstrate.
The pressure-sensitive adhesive contained in the linerless pressure-sensitive adhesive layer of the present invention does not exhibit pressure-sensitive adhesive properties at room temperature, and exhibits pressure-sensitive adhesive properties when heated (hot melt pressure-sensitive adhesive, heat-active pressure-sensitive adhesive (delayed tack-type pressure-sensitive adhesive) And the like (self-adhesive pressure-sensitive adhesive, etc.) that exhibit adhesiveness when pressed.

The hot melt pressure-sensitive adhesive is preferably composed of a thermoplastic resin, a wax, and a tackifier, and melts into a liquid state by heating and exhibits adhesiveness.
This thermoplastic resin is composed of ethylene- (meth) acrylic acid copolymer, (meth) acrylic acid- (meth) acrylic ester copolymer, α-olefin-maleic anhydride copolymer, styrene- (meth) acrylic acid. A copolymer etc. are mentioned.
The waxes include carnauba wax, candelilla wax, montan wax, fatty acid, fatty acid glyceride, polyethylene wax, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, polypropylene wax, wax obtained by oxidizing these, and ethylene-acrylic acid copolymer wax. And ethylene-methacrylic acid copolymer wax.
Examples of tackifiers include rosin, rosin derivatives (hydrogenated rosin, disproportionated rosin, polymerized rosin, acrylic acid modified rosin, fumaric acid modified rosin, maleic acid modified rosin, rosin esters thereof (alcohol, glycerin, pentaerythritol, etc. Esterified rosin)), terpene resin (α-pinene, β-pinene), terpene phenol resin, aromatic modified terpene resin, hydrogenated terpene resin, aliphatic petroleum resin, aromatic petroleum resin, copolymer Examples include petroleum resins, alicyclic petroleum resins, coumarone-indene resins, styrene resins, and phenol resins.

The thermoactive adhesive (delay tack adhesive) is preferably composed of a thermoplastic resin, a solid plasticizer, and a tackifier, and exhibits adhesiveness when heated.
This thermoplastic resin includes methyl methacrylate (Tg = 105 ° C.), ethyl acrylate (Tg = −22 ° C.), butyl acrylate (Tg = −54 ° C.), 2-ethylhexyl acrylate (Tg = −85 ° C.), carboxy-poly Caprolactone acrylate (Tg = −41 ° C.), vinyl aromatic compounds such as succinic acid monohydroxyethyl acrylate (Tg = −40 ° C.), styrene (Tg = 100 ° C.), vinyl chloride (Tg = 80 ° C.), vinylidene chloride ( Vinyl halides such as Tg = −20 ° C., vinyl acetate (Tg = 30 ° C.), vinyl esters such as vinyl propionate (Tg = 10 ° C.), ethylene (Tg = −125 ° C.), butadiene (Tg = −109) )) And other monomers such as acrylonitrile (Tg = 130 ° C.) alone. Or it is the copolymer used 2 or more types, and it is also possible to mix and use 2 or more types of thermoplastic resins.

As the solid plasticizer, a benzoic acid ester compound, a hindered phenol ester compound, or the like is preferably used.
Examples of the benzoic acid ester compounds include benzoic acid sucrose, benzoic acid diethylene glycol ester, benzoic acid glyceride, benzoic acid pentaerythritol ester, benzoic acid trimethylolethane ester, and benzoic acid trimethylolpropane ester. Among these, benzoic acid trimethylolpropane ester is particularly preferably used.

Examples of the hindered phenol ester compound include triethylene glycol bis [3- (3-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol bis [3- (3-t-butyl-4-hydroxy-). 5-methylphenyl) propionate], triethylene glycol bis [3- (3,5-di-tert-butyl-4-hydroxy-phenyl) propionate], 1,6-hexanediol bis [3- (3-t- Butyl-4-hydroxyphenyl) propionate], 1,6-hexanediol bis [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate], 1,6-hexanediol bis [3- ( 3,5-di-tert-butyl-4-hydroxyphenyl) propionate], thiobis [eth 3- (3-t-butyl-4-hydroxyphenyl) propionate], thiobis [ethylene 3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate], thiobis [ethylene 3- (3 5-di-t-butyl-4-hydroxyphenyl) propionate]. Among these, triethylene glycol bis [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate], 1,6-hexanediol bis [3- (3,5-di-t- Butyl-4-hydroxyphenyl) propionate] and thiobis [ethylene 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] are particularly preferably used.
These solid plasticizers can also be used as a mixture of two or more. In addition, the aqueous dispersion of the solid plasticizer is prevented from settling, and from the viewpoint of the surface properties (smoothness) of the coating layer, the dispersion particle size should be less than a certain value by a dispersing / pulverizing machine such as a ball mill or a handy mill. It is preferable to adjust.

Examples of tackifiers include rosin, hydrogenated rosin and derivatives thereof, rosin resins such as resin acid dimers, terpene resins such as terpene resins, aromatic modified terpene resins, hydrogenated terpene resins, and terpene-phenol resins. , Aliphatic petroleum resins, aromatic petroleum resins, alicyclic petroleum resins, styrene resins, phenol resins, and the like. These resins are used alone or in combination of two or more.
In the thermally active adhesive, a thickener, a surfactant, an antifoaming agent, a lubricant, a colorant, a pigment, and the like may be appropriately blended as long as the adhesiveness is not inhibited.

The activation temperature of the thermally active pressure-sensitive adhesive used in the present invention is preferably 50 to 100 ° C. The activation temperature is the minimum temperature necessary for the thermally active adhesive to exhibit adhesiveness, and is a value obtained by measuring the minimum temperature at which adhesiveness has developed. When the activation temperature is less than 50 ° C., a problem of unintentional adhesion between the adhesive layer and the heat-sensitive recording layer, that is, so-called blocking easily occurs during storage. On the other hand, if the temperature exceeds 100 ° C., the heating temperature necessary to develop the adhesiveness of the thermally active pressure-sensitive adhesive is high.
For the measurement of the active temperature, a thermal inclination tester (manufactured by Toyo Seiki Seisakusho, settable temperature range 50 to 250 ° C.) is used, and the adhesive coated surface is brought into contact with a hot plate set at an arbitrary temperature for 5 seconds. After that, the lowest temperature at which expression of adhesiveness was confirmed by touching with a finger was defined as the activation temperature.

The thermoplastic resin, solid plasticizer, and tackifier can be appropriately selected and used so that the activation temperature of the thermally active adhesive used in the present invention is 50 to 100 ° C. Moreover, it is preferable that the weight ratio of the solid content of a thermoplastic resin, a solid plasticizer, and a tackifier is thermoplastic resin: solid plasticizer: tackifier = 20-40: 50-70: 10-20.
Specific examples of the thermally active adhesive used in the present invention include Heat Magic DW1040W (manufactured by Toyo Ink, active temperature: 50 ° C.), Eco Brid 5610 (manufactured by Daicel Finechem, active temperature: 70 ° C.), Eco Brid TM- 1 (manufactured by Daicel Finechem, active temperature: 100 ° C.), Eco Brid S-1 (manufactured by Daicel Fine Chem, active temperature: 90 ° C.), Eco Brid TM-100 (manufactured by Daicel Fine Chem, active temperature: 70 ° C.), Eco Brid 5635 (Daicel FineChem, active temperature: 70 ° C), Eco Brid 5640 (Daicel FineChem, active temperature: 70 ° C), Dick Seal DLA-820K (Dainippon Ink, active temperature: 80 ° C) , Dick seal ED-920K (Dainippon Ink Co., Ltd., activation temperature: 90 ° C.) It is.

The self-adhesive pressure-sensitive adhesive used in the present invention can be bonded by overlapping and pressurizing linerless pressure-sensitive adhesive layers containing the self-adhesive pressure-sensitive adhesive. The linerless pressure-sensitive adhesive layers have high adhesion (also referred to as self-adhesion), but the adhesion to other layers is moderately low. Therefore, it is not necessary to use a release paper (liner), and it can be used in a roll form or a laminated form.
Examples of the self-adhesive pressure-sensitive adhesive include conventionally known ones such as those composed of natural rubber emulsion or synthetic rubber emulsion.
In the self-adhesive adhesive, auxiliary agents such as wax, surfactant, thickener, antifoaming agent, lubricant, colorant, tackifier, antioxidant, pigment, etc., as long as the adhesiveness is not inhibited. May be appropriately blended.

  If the coating amount of the pressure-sensitive adhesive for forming the linerless pressure-sensitive adhesive layer is small, the initial adhesion as a thermosensitive recording tag is insufficient, and if it is too large, it is difficult to obtain a smooth coated surface, and drying properties are also possible. Also decreases. Although depending on the paper quality of the support, the dry coating amount of the hot melt pressure-sensitive adhesive is preferably about 3 to 20 g / m2. The dry coating amount of the thermally active pressure-sensitive adhesive is preferably about 5 to 50 g / m2. The dry coating amount of the self-adhesive adhesive is, for example, about 2 to 50 g / m 2 per side.

In the thermosensitive recording tag of the present invention, an intermediate layer may be provided between the support and the linerless pressure-sensitive adhesive layer. This intermediate layer is usually composed of a pigment and a binder, and a cross-linking agent, an antifoaming agent, a lubricant and the like may be added as necessary. As the pigment and the binder, a binder that can be used in the above-mentioned heat-sensitive recording layer can be used.
Although the compounding quantity of each component in an intermediate | middle layer is not specifically limited, Usually, a binder is about 10-40 weight part by solid content with respect to 100 weight part of pigments. Moreover, the dry coating amount of the intermediate layer is about 1 to 10 g / m2.

  The following examples illustrate the invention but are not intended to limit the invention. In Examples, Comparative Examples, and Reference Examples, “parts” represents “parts by weight” and “%” represents “% by weight” unless otherwise specified. Various dispersions and coating solutions were prepared as follows.

[Preparation of each coating solution]
Undercoating liquids 1-2 were prepared by stirring and dispersing a composition comprising the following composition.
<Coating liquid 1 for undercoat layer>
Baked kaolin (trade name: Ansilex 90, manufactured by BASF) 100.0 parts Styrene-butadiene copolymer latex (manufactured by Nippon Zeon Co., Ltd.,
Product name: ST5526, solid content 48%) 10.0 parts water 50.0 parts <Coating liquid 2 for undercoat layer>
Firing kaolin (made by BASF, trade name: Ancilex 90) 50.0 parts Plastic hollow particles (made by Nippon Zeon, trade name: Nipol MH8108A,
185.0 parts Styrene / butadiene copolymer latex (manufactured by Nippon Zeon Co., Ltd.)
(Product name: ST5526, solid content 48%) 10.0 parts

  Developer liquid dispersion (A1 liquid to A8 liquid), leuco dye dispersion liquid (B liquid) and sensitizer dispersion liquid (C liquid) of the following composition were each separately separated to a mean particle size of 0.5 microns with a sand grinder. Wet grinding was performed until

Developer dispersion 1 (A1 solution)
4-hydroxy-4′-benzyloxydiphenyl sulfone (manufactured by Nikka Chemical Co., Ltd.,
Product name: BPS-MA3) 6.0 parts Completely saponified polyvinyl alcohol aqueous solution (trade name: PVA117, manufactured by Kuraray Co., Ltd.)
(Solid content 10%) 5.0 parts Water 1.5 parts Developer dispersion 2 (A2 liquid)
Urea urethane compound represented by the chemical formula (Chemical Formula 2) (Chemipro Kasei Co., Ltd.,
Product name: UU) 6.0 parts Completely saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray Co., Ltd., PVA117) 5.0 parts Water 1.5 parts Developer dispersion 3 (A3 liquid)
4,4′-dihydroxydiphenyl sulfone (manufactured by Nikka Chemical Co., Ltd.,
Product name: BPS-P (T)) 6.0 parts Completely saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray Co., Ltd., PVA117) 5.0 parts Water 1.5 parts Developer dispersion 4 (A4 liquid)
4-hydroxy-4′-n-propoxydiphenyl sulfone (Mitsubishi Chemical Corporation,
Product name: TOMILAC KN) 6.0 parts 5.0 parts of a completely saponified polyvinyl alcohol aqueous solution (Pura117, manufactured by Kuraray Co., Ltd.)
Water 1.5 parts Developer dispersion 5 (A5 liquid)
Diphenylsulfone cross-linking compound (Nippon Soda Co., Ltd., trade name: D90) 6.0 parts Completely saponified polyvinyl alcohol aqueous solution (Kuraray Co., PVA117) 5.0 parts Water 1.5 parts

Developer dispersion 6 (A6 liquid)
Urea compounds represented by the chemical formula (Chemical Formula 8) (manufactured by API Corporation,
Product name: SU727) 6.0 parts Completely saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray Co., Ltd., PVA117) 5.0 parts Water 1.5 parts

Developer dispersion 7 (A7 liquid)
4-Hydroxyphenyl-4′-phenoxyphenyl sulfone (chemical formula (Chemical Formula 9))
6.0 parts Completely saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray Co., Ltd., PVA117) 5.0 parts Water 1.5 parts

Developer dispersion 8 (A8 liquid)
2,4′-dihydroxydiphenyl sulfone (manufactured by Nikka Chemical Co., Ltd.,
Product name: BPS-24C) 6.0 parts Completely saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray Co., Ltd., PVA117) 5.0 parts Water 1.5 parts

Leuco dye dispersion (liquid B)
3-dibutylamino-6-methyl-7-anilinofluorane (manufactured by Yamamoto Kasei Co., Ltd.,
Product name: ODB-2) 6.0 parts Completely saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray Co., Ltd., 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 (manufactured by Kuraray Co., Ltd., PVA117) 5.0 parts Water 1.5 parts

Subsequently, each dispersion liquid was mixed in the following ratio to prepare thermal recording layer coating liquids 1 to 9.
<Thermosensitive recording layer coating solution 1>
Developer Dispersion (Liquid A1) 18.0 parts Developer Dispersion (Liquid A2) 18.0 parts Leuco Dye Dispersion (Liquid B) 18.0 parts Sensitizer Dispersion (Liquid C) 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 (Pura117, manufactured by Kuraray Co., Ltd.)
25.0 parts

<Thermosensitive recording layer coating solution 2>
Developer Dispersion (Liquid A1) 36.0 parts Leuco Dye Dispersion (Liquid B) 18.0 parts Sensitizer Dispersion (Liquid C) 9.0 parts Silica Dispersion (Mizusawa Chemical Co., Mizukasil P-) 537) 17.5 parts Completely saponified polyvinyl alcohol aqueous solution (Kuraray Co., PVA117)
25.0 parts

<Thermosensitive recording layer coating solution 3>
Developer Dispersion (Liquid A2) 36.0 parts Leuco Dye Dispersion (Liquid B) 18.0 parts Sensitizer Dispersion (Liquid C) 9.0 parts Silica Dispersion (Mizusawa Chemical Co., Ltd., Mizukasil P-) 537) 17.5 parts Completely saponified polyvinyl alcohol aqueous solution (Kuraray Co., PVA117)
25.0 parts

<Thermosensitive recording layer coating solution 4>
Developer dispersion (liquid A3) 18.0 parts Developer dispersion (liquid A2) 18.0 parts Leuco dye dispersion (liquid B) 18.0 parts Sensitizer dispersion (liquid C) 9.0 Part Silica dispersion (Mizusawa Chemical Co., Ltd., Mizukasil P-537) 17.5 parts Complete saponification type polyvinyl alcohol aqueous solution (Kuraray Co., Ltd., PVA117)
25.0 parts

<Thermosensitive recording layer coating solution 5>
Developer dispersion (liquid A4) 18.0 parts Developer dispersion (liquid A2) 18.0 parts Leuco dye dispersion (liquid B) 18.0 parts Sensitizer dispersion (liquid C) 9.0 Part Silica dispersion (Mizusawa Chemical Co., Ltd., Mizukasil P-537) 17.5 parts Complete saponification type polyvinyl alcohol aqueous solution (Kuraray Co., Ltd., PVA117)
25.0 parts

<Thermosensitive recording layer coating solution 6>
Developer dispersion (liquid A5) 18.0 parts Developer dispersion (liquid A2) 18.0 parts Leuco dye dispersion (liquid B) 18.0 parts Sensitizer dispersion (liquid C) 9.0 Part Silica dispersion (Mizusawa Chemical Co., Ltd., Mizukasil P-537) 17.5 parts Complete saponification type polyvinyl alcohol aqueous solution (Kuraray Co., Ltd., PVA117)
25.0 parts

<Thermosensitive recording layer coating solution 7>
Developer dispersion (liquid A1) 18.0 parts Developer dispersion (liquid A6) 18.0 parts Leuco dye dispersion (liquid B) 18.0 parts Sensitizer dispersion (liquid C) 9.0 Part Silica dispersion (Mizusawa Chemical Co., Ltd., Mizukasil P-537) 17.5 parts Complete saponification type polyvinyl alcohol aqueous solution (Kuraray Co., Ltd., PVA117)
25.0 parts

<Thermosensitive recording layer coating solution 8>
Developer Dispersion (Liquid A1) 18.0 parts Developer Dispersion (Liquid A2) 18.0 parts Leuco Dye Dispersion (Liquid B) 18.0 parts Sensitizer Dispersion (Liquid C) 9.0 Part Silica dispersion (Mizusawa Chemical Co., Ltd., Mizukasil P-537) 7.5 parts Completely saponified polyvinyl alcohol aqueous solution (Kuraray Co., PVA117)
25.0 parts

<Thermosensitive recording layer coating solution 9>
Developer dispersion (liquid A7) 18.0 parts Developer dispersion (liquid A2) 18.0 parts Leuco dye dispersion (liquid B) 18.0 parts Sensitizer dispersion (liquid C) 9.0 Part Silica dispersion (Mizusawa Chemical Co., Ltd., Mizukasil P-537) 17.5 parts Complete saponification type polyvinyl alcohol aqueous solution (Kuraray Co., Ltd., PVA117)
25.0 parts

Subsequently, the composition which consists of the following ratio was mixed and the protective layer coating liquids 1-2 were prepared.
<Protective layer coating solution 1>
Aluminum hydroxide dispersion (manufactured by Martinsberg,
Product name: Martyfin OL, solid content 50%) 9.0 parts Carboxy-modified polyvinyl alcohol aqueous solution (Kuraray Co., Ltd., product name: KL318)
Degree of polymerization: about 1800, degree of saponification: 85 to 90 mol%, solid content 10%) 30.0 parts Polyamide epichlorohydrin resin (manufactured by Seiko PMC, trade name: WS4030,
4.0 parts modified polyamine resin (manufactured by Taoka Chemical Co., Ltd., trade name: Sumirez resin SPI-102A, solid content 25%)
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

<Protective layer coating solution 2>
Aluminum hydroxide dispersion (manufactured by Martinsberg,
Product name: Martyfin OL, solid content 50%) 9.0 parts Non-core shell type acrylic resin (Mitsui Chemicals, product name: ASN1004K,
Tg 55 ° C., solid content 18%) 16.6 parts water 10.0 parts

[Example 1]
On one side of the support (basis weight 47 g / m2 high-quality paper), the undercoat layer coating liquid 1 is applied by a vent blade method so that the coating amount is 10.0 g / m2 in terms of solid content, and then dried. The undercoat layer-coated paper was obtained.
On the undercoat layer of this undercoat layer-coated paper, the thermosensitive recording layer coating solution 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 the super calendar Then, the paper was processed so as to have a smoothness of 500 to 1000 seconds to prepare a heat-sensitive recording layer coated paper.
Next, the protective layer coating solution 1 is applied on the heat-sensitive recording layer of the heat-sensitive recording layer-coated paper by a rod blade method so that the coating amount is 2.0 g / m 2 in terms of solid content, and then dried. To produce a heat-sensitive recording material.
[Example 2]
Except that the blending amount of the developer dispersion liquid (A1 liquid) in the thermal recording layer coating liquid 8 was 31.5 parts and the blending amount of the developer dispersion liquid (A2 liquid) was 4.5 parts. A thermosensitive recording material was produced in the same manner as in Example 1.

[Example 3]
Except that the blending amount of the developer dispersion (A1 liquid) in the thermosensitive recording layer coating liquid 8 was 4.5 parts and the blending amount of the developer dispersion (A2 liquid) was 31.5 parts. A thermosensitive recording material was produced in the same manner as in Example 1.
[Example 4]
Except that the blending amount of the developer dispersion (A1 liquid) in the thermal recording layer coating liquid 8 was 25.5 parts and the blending amount of the developer dispersion (A2 liquid) was 10.5 parts. A thermosensitive recording material was produced in the same manner as in Example 1.
[Example 5]
A thermosensitive recording material was produced in the same manner as in Example 4 except that the undercoat layer coating solution 2 was used instead of the undercoat layer coating solution 1.
[Example 6]
A heat-sensitive recording material was produced in the same manner as in Example 5 except that the protective layer coating solution 2 was used instead of the protective layer coating solution 1.

[Example 7]
A mixture having the following composition was mixed and stirred to prepare an adhesive layer coating solution (self-adhesive adhesive coating solution).
<Adhesive layer coating solution>
Natural rubber latex 100.0 parts Silica dispersion (manufactured by Mizusawa Chemical Co., Ltd., Mizukasil P-537, solid content 25%) 20.0 parts Water 100.0 parts Thermosensitive recording of the support of the thermosensitive recording medium produced in Example 1 On the side opposite to the layer, this pressure-sensitive adhesive layer coating solution was applied by an air knife method so that the coating amount was 13.0 g / m 2 as a solid content, followed by drying to produce a thermosensitive recording tag.

[Example 8]
A heat-sensitive recording material was produced in the same manner as in Example 4 except that a polyester film (manufactured by Toyobo Co., Ltd., Cosmo Shine A4300, thickness 50 μm) was used instead of the support (quality paper of basis weight 47 g / m 2).
[Example 9]
A thermosensitive recording material was produced in the same manner as in Example 4 except that polyester-based synthetic paper (Kamishine KS100, thickness 50 μm, manufactured by Toyobo Co., Ltd.) was used instead of the support (high-quality paper having a basis weight of 47 g / m 2). did.

[Comparative Example 1]
A heat-sensitive recording material was prepared in the same manner as in Example 1 except that instead of the heat-sensitive recording layer coating solution 8, a silica dispersion in the heat-sensitive recording layer coating solution 2 was used in an amount of 7.0 parts. Produced.
[Comparative Example 2]
A heat-sensitive recording material was prepared in the same manner as in Example 1 except that instead of the heat-sensitive recording layer coating solution 8, a silica dispersion in the heat-sensitive recording layer coating solution 3 was used in an amount of 7.0 parts. Produced.
[Comparative Example 3]
A heat-sensitive recording material was prepared in the same manner as in Example 1 except that instead of the heat-sensitive recording layer coating solution 8, a silica dispersion in the heat-sensitive recording layer coating solution 4 was used in an amount of 7.0 parts. Produced.
[Comparative Example 4]
A heat-sensitive recording medium was prepared in the same manner as in Example 1 except that instead of the heat-sensitive recording layer coating solution 8, the silica dispersion in the heat-sensitive recording layer coating solution 5 was used in an amount of 7.0 parts. Produced.

[Comparative Example 5]
A heat-sensitive recording material was prepared in the same manner as in Example 1 except that instead of the heat-sensitive recording layer coating solution 8, the silica dispersion in the heat-sensitive recording layer coating solution 6 was used in an amount of 7.0 parts. Produced.
[Comparative Example 6]
A heat-sensitive recording material was prepared in the same manner as in Example 1 except that instead of the heat-sensitive recording layer coating solution 8, a silica dispersion in the heat-sensitive recording layer coating solution 7 was used in an amount of 7.0 parts. Produced.
[Comparative Example 7]
A heat-sensitive recording medium was prepared in the same manner as in Example 1 except that instead of the heat-sensitive recording layer coating liquid 8, the silica dispersion in the heat-sensitive recording layer coating liquid 9 was used in an amount of 7.0 parts. Produced.

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

[Comparative Example 11]
A heat-sensitive recording material was prepared in the same manner as in Comparative Example 1 except that a polyester film (manufactured by Toyobo Co., Ltd., Cosmo Shine A4300, thickness 50 μm) was used instead of the support (high-quality paper having a basis weight of 47 g / m 2).
[Comparative Example 12]
A heat-sensitive recording material was produced in the same manner as in Comparative Example 2 except that a polyester film (manufactured by Toyobo Co., Ltd., Cosmo Shine A4300, thickness 50 μm) was used instead of the support (high-quality paper having a basis weight of 47 g / m 2).
[Comparative Example 13]
A thermosensitive recording material was produced in the same manner as in Comparative Example 1 except that polyester-based synthetic paper (Toyobo Co., Ltd., Kamishine KS100, thickness 50 μm) was used instead of the support (high-quality paper having a basis weight of 47 g / m2). did.
[Comparative Example 14]
A thermosensitive recording material was prepared in the same manner as in Comparative Example 2 except that polyester-based synthetic paper (Toyobo Co., Ltd., Kamishine KS100, thickness 50 μm) was used instead of the support (high-quality paper having a basis weight of 47 g / m2). did.

[Reference Example 1]
On one side of the support (basis weight 47 g / m2 high-quality paper), the undercoat layer coating liquid 1 is applied by a vent blade method so that the coating amount is 10.0 g / m2 in terms of solid content, and then dried. The undercoat layer-coated paper was obtained.
On the undercoat layer of this undercoat layer-coated paper, the thermosensitive recording layer coating solution 1 is applied by the rod blade method so that the coating amount is 6.0 g / m 2 in terms of solid content, then dried, and the super calendar A thermal recording material was produced by processing so that the smoothness was 500 to 1000 seconds.

[Reference Example 2]
Reference was made except that the blending amount of the developer dispersion (A1 liquid) in the thermosensitive recording layer coating liquid 1 was 31.5 parts and the blending amount of the developer dispersion (A2 liquid) was 4.5 parts. A thermosensitive recording material was produced in the same manner as in Example 1.
[Reference Example 3]
Reference was made except that the blending amount of the developer dispersion liquid (A1 liquid) in the thermosensitive recording layer coating liquid 1 was 25.5 parts and the blending amount of the developer dispersion liquid (A2 liquid) was 10.5 parts. A thermosensitive recording material was produced in the same manner as in Example 1.

[Reference Example 4]
A thermosensitive recording material was produced in the same manner as in Reference Example 1, except that the thermosensitive recording layer coating solution 2 was used instead of the thermosensitive recording layer coating solution 1.
[Reference Example 5]
A thermosensitive recording material was prepared in the same manner as in Reference Example 1 except that the thermosensitive recording layer coating solution 3 was used instead of the thermosensitive recording layer coating solution 1.
[Reference Example 6]
A thermosensitive recording material was produced in the same manner as in Reference Example 1 except that the thermosensitive recording layer coating solution 4 was used instead of the thermosensitive recording layer coating solution 1.
[Reference Example 7]
A thermosensitive recording material was prepared in the same manner as in Reference Example 1 except that the thermosensitive recording layer coating solution 5 was used instead of the thermosensitive recording layer coating solution 1.

[Reference Example 8]
A thermosensitive recording material was produced in the same manner as in Reference Example 1 except that the thermosensitive recording layer coating solution 6 was used instead of the thermosensitive recording layer coating solution 1.
[Reference Example 9]
A thermosensitive recording material was produced in the same manner as in Reference Example 1, except that the thermosensitive recording layer coating solution 7 was used instead of the thermosensitive recording layer coating solution 1.
[Reference Example 10]
Reference was made except that the blending amount of the developer dispersion liquid (A1 liquid) in the thermosensitive recording layer coating liquid 1 was 4.5 parts and the blending quantity of the developer dispersion liquid (A2 liquid) was 31.5 parts. A thermosensitive recording material was produced in the same manner as in Example 1.
[Reference Example 11]
A thermosensitive recording material was produced in the same manner as in Reference Example 1 except that the thermosensitive recording layer coating solution 9 was used instead of the thermosensitive recording layer coating solution 1.

The following evaluation was performed about the produced thermal recording body and the thermal recording tag.
<Coloring performance (print density)>
About the produced thermal recording medium and the thermal recording tag, TH-PMD made by Okura Electric Co., Ltd. (with thermal recording paper printing tester, Kyocera thermal head installed), applied energy 0.35 mJ / dot, printing speed 50 mm / A checkerboard pattern was printed in sec.
The printing density of the printing part was measured with a Macbeth densitometer (RD-914, using an amber filter), and the color development performance (printing density) was evaluated.

<Heat resistance of blank paper part>
The produced heat-sensitive recording material and heat-sensitive recording tag were treated under an environmental condition of 80 ° C. for 24 hours and then allowed to stand for 3 hours under an environmental condition of 23 ° C. × 50% RH.
The density of the non-printed area (blank area) is measured with a Macbeth densitometer (RD-914, using an amber filter), and the ground color development value is calculated from the difference between the values before and after processing. Part) was evaluated for heat resistance.
Ground color development value = (density of non-printed part after processing)-(density of non-printed part 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 Impossibility: Ground color development value is 0.00. 5 or more

<Bar code reading aptitude>
The prepared thermal recording medium and thermal recording tag were placed under the following environmental conditions (1) to (3), and then a label printer 140XiIII manufactured by Zebra Corporation was used, the printing level +10, the printing speed 15.2 cm / second (6 inches). Barcode (CODE39) was printed at a rate of 1 sec.
(1) The mixture was allowed to stand for 3 hours under 23 ° C. × 50% RH environmental conditions.
(2) After being placed under 80 ° C. environmental conditions for 24 hours, it was allowed to stand under 23 ° C. × 50% RH environmental conditions for 3 hours.
(3) After being placed under 50 ° C. × 90% RH environmental condition for 24 hours, it was allowed to stand under 23 ° C. × 50% RH environmental condition for 3 hours.
(4) Further, for the produced thermal recording medium and thermal recording tag, after the processing of (1) above, using a label printer 140XiIII manufactured by Zebra, the printing level +10, the printing speed 15.2 cm / second (6 inches / second) ), A bar code (CODE39) was printed, placed under 50 ° C. × 90% RH environmental conditions for 5 days, and then allowed to stand under 23 ° C. × 50% RH environmental conditions for 3 hours.

Next, a reading test was performed on the printed barcode with a barcode verification machine (manufactured by Honeywell, QCPC600, light source 640 nm) to evaluate barcode readability. The evaluation results are shown in ANSI standard symbol grades.
Symbol grade: Bar code is divided into 10 in the vertical direction with the bar, and a reading test is performed once for each location. The average value is (excellent) A, B, C, D, F (poor) Represented by

The evaluation results are shown in Table 1.

  From Table 1, the heat-sensitive recording layer 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) in a specific ratio as a color developer, and further a heat-sensitive recording layer. When the protective layer is provided on the top, it can be seen that the color development performance in a harsh environment, in particular, the barcode readability is excellent ((2) to (4) with respect to the barcode read characteristic (1)).

Claims (13)

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

(In the formula, R1 represents a hydrogen atom or a hydroxyl group, R2 and R3 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an alkoxy group, and m represents an integer of 1 to 3).

The heat-sensitive recording material according to claim 1, wherein the support is made of a film or synthetic paper. The heat-sensitive recording material according to claim 1, wherein the protective layer contains carboxy-modified polyvinyl alcohol or a non-core-shell type acrylic resin as a binder. The protective layer contains carboxy-modified polyvinyl alcohol as a binder, and further contains an epichlorohydrin resin and a polyamine / polyamide resin (excluding those contained in the epichlorohydrin resin) as a crosslinking agent. Item 3. The thermal recording material according to Item 1 or 2. The heat-sensitive recording material according to claim 3, wherein the protective layer contains a non-core-shell type acrylic resin having a glass transition point (Tg) of 90 ° C. or less as a binder. The heat-sensitive recording material according to claim 3 or 5, wherein the protective layer contains a non-core shell acrylic resin having a glass transition point (Tg) higher than 50 ° C as a binder. The urea urethane compound represented by the general formula (Chemical Formula 2) is contained in a proportion 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 1). The heat-sensitive recording material according to any one of 1 to 6. The heat-sensitive recording material according to any one of claims 1 to 7, wherein the sulfone compound is represented by the following general formula (Formula 3).

(Wherein R2 and R3 are defined in the same manner as described above, and m is 1 or 2). The thermosensitive recording material according to claim 8, wherein at least one of R2 and R3 is a hydrogen atom. The thermosensitive recording material according to claim 8 or 9, wherein m is 1. The heat-sensitive recording material according to claim 8, wherein the sulfone compound is 4-hydroxy-4′-benzyloxydiphenyl sulfone. The thermosensitive recording tag which provided the linerless adhesive layer in the opposite side to the thermosensitive recording layer of the support body of the thermosensitive recording body as described in any one of Claims 1-11. The thermosensitive recording tag according to claim 12, further comprising an intermediate layer between the support and the linerless pressure-sensitive adhesive layer.