JP2014184692A - Thermosensitive recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosensitive recording medium using, as a support medium, a plastic film having abated coating defects, excellent in terms of printing density and printing runnability via a thermal printer, and exhibiting high image stabilities against plasticizers and oils.SOLUTION: A plastic film is used as a support medium, whereas a thermosensitive recording layer and a protective layer provided as the outermost layer are configured in proper order atop the former, whereas an acrylic resin and a polyolefinic resin are included within this protective layer, whereas a metal chelate-type coloring component including, as main components, an electron acceptor and an electron donor each having a specified structure is included within the thermosensitive recording layer.

Description

  The present invention relates to a heat-sensitive recording body in which a heat-sensitive recording layer and a protective layer are provided on a support made of a plastic film, and more specifically, with a plastic film as a support, coating defects are reduced, and print density, The present invention relates to a heat-sensitive recording material that is excellent in print runnability by a thermal printer and has high image stability against plasticizers and oils.

The heat-sensitive recording medium usually contains 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”) such as a phenolic compound, After grinding and dispersing into fine particles, respectively, the two are mixed, and a coating solution obtained by adding a binder, a filler, a sensitivity improver, a lubricant and other auxiliaries is added to paper, synthetic paper, film, It is coated on a support such as plastic and is colored by an instantaneous chemical reaction by heating with a thermal head, hot stamp, thermal pen, laser beam, etc., and a recorded image is obtained. Thermosensitive recording media are widely used in facsimiles, computer terminal printers, automatic ticket vending machines, measurement recorders, and the like.
However, since the color development reaction between the leuco dye and the developer is a reversible reaction, there is a problem that the recorded image is decolored with time. This decolorization reaction is accelerated under light, high temperature, and high humidity atmosphere, and particularly accelerated by contact with plasticizers and oils such as salad oil contained in wrap films, etc. The thermal recording material tends to cause a problem that the recorded image cannot be read due to decoloring.
In order to deal with such a problem that the recorded image is decolored, a heat-sensitive recording material containing a metal chelate-type color forming component composed of an electron donor and an electron acceptor is disclosed (Patent Document 1).
On the other hand, since the dimensional stability and strength are good, the number of heat-sensitive recording bodies using a plastic film as a support is increasing (Patent Document 2, etc.), but when a plastic film is used as a support for a heat-sensitive recording body. In order to solve the problem that the coating layer is peeled off due to moisture, a thermal recording material has been developed in which a protective layer containing a polyolefin resin and a glossy layer are provided on a thermal recording layer (Patent Document 3).
In addition, in a heat-sensitive recording material used for outdoor applications requiring durability and water resistance, a protective layer containing an acrylic resin emulsion is provided on the heat-sensitive recording layer (patent) Literature 4-7 etc.).

JP 06-155915 A JP2007-130991 JP2001-50813A International publication WO2010 / 110209 International Publication WO2007 / 049621 JP-A-6-262853 JP 2004-74531 A

When a plastic film is used as the support for the heat-sensitive recording material, a protective layer is generally provided on the heat-sensitive recording layer in order to increase surface strength and water resistance.
However, since plastic films are less water-absorbing than water and other solvents compared to paper, ripple-like coating defects occur due to the presence of water and other solvents in the thermal recording layer. Easy (see Comparative Example 2 described later, FIG. 1). Since this coating defect is caused by a difference in the light transmission state, it is more noticeable when a transparent plastic film is used as the support. In addition, this problem becomes more prominent when a coating liquid that improves the adhesion and tackiness to the plastic film is used.
This problem can be solved by including an olefin resin in the protective layer (Comparative Example 5 to be described later). On the other hand, since the olefin resin has low heat resistance and surface strength, sticking during printing is not possible. Problems arise. It has been proposed to solve this problem by further providing a coating layer on the protective layer (Patent Document 2).
However, if a coating layer is further provided on the protective layer, the energy applied from the thermal head or the like is absorbed by the coating layer, making it difficult to obtain a sufficient print density. Further, the olefin resin has a problem that the image stability with respect to the plasticizer and oil is low, that is, the plasticizer resistance and the oil resistance are low.
Therefore, the present invention provides a thermal recording material in which a plastic film is used as a support, and a thermal recording layer and a protective layer as an outermost layer are sequentially provided thereon. It is an object of the present invention to provide a heat-sensitive recording material that is excellent in running properties and has high image stability against plasticizers and oils.

As a result of intensive studies, the inventors of the present invention have used a plastic film as the support, sequentially provided a heat-sensitive recording layer and a protective layer as the outermost layer, and this protective layer contains an acrylic resin and a polyolefin-based resin. By adding a metal chelate-type color-forming component containing an electron acceptor and an electron donor having a specific structure as main components, the coating can be applied while exhibiting normal performance with respect to the water resistance required for such a heat-sensitive recording material. It has been found that a heat-sensitive recording material can be obtained that can prevent the occurrence of work defects, is excellent in print density and print runnability by a thermal printer, and has high image stability against plasticizers and oils. It came to.
That is, the present invention relates to a thermosensitive recording layer containing a colorless or light-colored electron-donating leuco dye and an electron-accepting developer on a plastic film, and a thermosensitive recording medium having a protective layer as an outermost layer on the thermosensitive recording layer. In this, the protective layer contains an acrylic resin and a polyolefin resin, and the thermosensitive recording layer contains a metal chelate-type color forming component containing an electron acceptor and an electron donor as main components, and the electron acceptor comprises A heat-sensitive recording material, which is a higher fatty acid metal salt having a saturated or unsaturated aliphatic group having 16 to 35 carbon atoms, wherein the electron donor is a polyvalent hydroxyaromatic compound represented by the following general formula (Formula 1): is there.

（式中、Ｒは炭素数が１８〜３５のアルキル基、

(Wherein R is an alkyl group having 18 to 35 carbon atoms,

（式中、Ｒ^１は炭素数が１８〜３５のアルキル基を表す。）を表し、−Ｘ−は−ＣＨ_２−、−ＣＯ_２−、−ＣＯ−、−Ｏ−、−ＣＯＮＨ−、−ＣＯＮＲ^２−（式中、Ｒ^２は炭素数が１８〜３５のアルキル基を表す。）、−ＳＯ_２−、−ＳＯ_３−またはＳＯ_２ＮＨ−を表し、ｎは２または３の整数を表す。）

(In the formula, ^{R 1} represents an alkyl group having a carbon number of 18 to 35.) Represent, _-X- is _{-CH 2 -, - CO 2 -} , - CO -, - O -, - CONH -, - CONR ² — (wherein R ² represents an alkyl group having 18 to 35 carbon atoms), —SO ₂ —, —SO ₃ — or SO ₂ NH—, and n represents an integer of 2 or 3 . )

  In the heat-sensitive recording material of the present invention, a heat-sensitive recording layer is provided on a plastic film (support), and a protective layer is provided thereon as an outermost layer, and this protective layer contains an acrylic resin and a polyolefin-based resin.

  Examples of the plastic film used in the present invention include a polyethylene terephthalate (PET) film, a triacetyl cellulose (TAC) film, and a polyethylene naphthalate (PEN) film. Specifically, examples include a norbornene-based film (trade name: ARTON film) manufactured by JSR, a cycloolefin-based film (trade name: ZEONOR film) manufactured by ZEON CORPORATION, and a composite film obtained by combining these films. it can. In particular, when the support is used in applications requiring light transmittance, the support preferably has a total light transmittance of 30% or more, more preferably 70% or more, among the resin films described above.

The polyolefin resin used in the present invention is a polymer of an olefin such as ethylene or propylene, and may be a monopolymer or a copolymer with other vinyl compounds.
The polyolefin resin used in the present invention is preferably an olefin / unsaturated carboxylic acid copolymer. As the olefin, ethylene, propylene, butylene and the like are preferable, and ethylene is particularly preferable. The unsaturated carboxylic acid is preferably (meth) acrylic acid (that is, acrylic acid or methacrylic acid), maleic acid, itaconic acid, fumaric acid and the like, and more preferably (meth) acrylic acid. The olefin / unsaturated carboxylic acid copolymer is preferably a copolymer of ethylene and (meth) acrylic acid or a copolymer of propylene and (meth) acrylic acid copolymer.
The weight average molecular weight of such a polyolefin-based resin is preferably 5,000 to 100,000, more preferably 10,000 to 50,000. If the weight average molecular weight is less than 5,000, blocking may occur. In addition, if the weight average molecular weight exceeds 100,000, there may be a problem in productivity.
Examples of the olefin / unsaturated carboxylic acid copolymer include Hitech S-3121, Hitech S-3123, Hitech S-3127 (manufactured by Toho Chemical Co., Ltd.), Seixen-A-GH, Seixen-AC, and Seixen. -N, Saixen-L (manufactured by Sumitomo Seika Co., Ltd.) and the like.

The acrylic resin used in the present invention comprises (meth) acrylic acid and a monomer component (excluding olefin) copolymerizable with (meth) acrylic acid. (Meth) acrylic acid is preferably blended in an amount of 1 to 10 parts per 100 parts of the acrylic resin. (Meth) acrylic acid is alkali-soluble and has the property of making an acrylic resin a water-soluble resin by the addition of a neutralizing agent. By changing the acrylic resin to a water-soluble resin, particularly when a pigment is contained in the protective layer, the binding property to the pigment is remarkably improved, and a protective layer having excellent strength even when containing a large amount of pigment is formed. be able to. Examples of the component copolymerizable with (meth) acrylic acid include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and isobutyl (meth) acrylate. , Alkyl acrylate resins such as pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, epoxy resins, silicone resins, styrene or derivatives thereof Examples of the modified alkyl acrylate resin such as the above-mentioned alkyl acrylate resin modified by (meth) acrylonitrile, acrylate ester, and hydroxyalkyl acrylate ester include (meth) acrylonitrile and / or methyl methacrylate. It is preferable. (Meth) acrylonitrile is preferably blended in an amount of 15 to 70 parts per 100 parts of the acrylic resin. Moreover, it is preferable that methyl methacrylate contains 20-80 parts in 100 parts of acrylic resins. When (meth) acrylonitrile and methyl methacrylate are included, it is preferable to blend 15 to 18 parts of (meth) acrylonitrile in 100 parts of acrylic resin and 20 to 80 parts of methyl methacrylate in 100 parts of acrylic resin.
The glass transition point (Tg) of the acrylic resin in the present invention is higher than 50 ° C and not higher than 95 ° C. When Tg is 50 ° C. or lower, the water resistance is improved, but sufficient heat resistance cannot be obtained, so that sticking tends to occur. On the other hand, if an acrylic resin having a high Tg is contained, the stick resistance and scratch resistance tend to be improved, but if the Tg is too high, the protective layer becomes brittle, and the water resistance, plasticizer resistance and solvent resistance are not sufficient. In some cases, the intended effect cannot be obtained. The Tg of acrylic resin is measured by differential scanning calorimetry (DSC).

  The acrylic resin used in the present invention is preferably a non-core-shell type acrylic resin. In general, the core-shell type acrylic resin is frequently used because it has excellent heat resistance compared to the non-core-shell type acrylic resin and has excellent stick resistance when used in a coating layer. However, the shell part of the core-shell type acrylic resin usually has a drawback that the color development sensitivity is poor because of its low thermal conductivity. On the other hand, the normal non-core shell type acrylic resin has low heat resistance and has the disadvantage that sticks and head scum are likely to be generated. However, the non-core shell type of Tg used in the present invention is higher than 50 ° C. and lower than 95 ° C. Acrylic resins are excellent in heat resistance, and therefore have the advantage of good color development sensitivity and good stick resistance and head residue resistance.

Moreover, it is preferable that the protective layer of this invention does not contain a pigment. Examples of the pigment include inorganic or organic fillers such as kaolin, calcined kaolin, aluminum hydroxide, silica, calcium carbonate, diatomaceous earth, talc, and titanium oxide.
In addition to the above components, the protective layer of the present invention includes fatty acid metal salts such as zinc stearate and calcium stearate, lubricants such as waxes and silicone resins, benzophenone-based and triazole-based UV absorbers, crosslinking agents, and dispersion agents. You may contain an agent, an antifoamer, antioxidant, fluorescent dye, etc., unless the effect of this invention is inhibited.

The blending amount of the polyolefin resin in the protective layer of the present invention is preferably 3 to 60% by weight, more preferably 5 to 30% by weight in terms of solid content.
The blending amount of the acrylic resin in the protective layer of the present invention is solid content, preferably 15 to 97% by weight, more preferably 50 to 95% by weight.
The blending weight ratio (solid content) of the polyolefin resin / acrylic resin is preferably 3/97 to 50/50, more preferably 5/95 to 40/60.
The total amount of the polyolefin resin and the acrylic resin in the protective layer is preferably 20 to 100% by weight, more preferably 40 to 90% by weight, as a solid content.

  The heat-sensitive recording layer of the present invention contains a metal chelate-type coloring component containing an electron acceptor and an electron donor as main components, and the electron acceptor has a saturated or unsaturated aliphatic group having 16 to 35 carbon atoms. The electron donor is a polyvalent hydroxyaromatic compound represented by the following general formula (Formula 1). Furthermore, you may contain a sensitizer, a binder, a crosslinking agent, a lubricant, said pigment, and other various components.

ここで、Ｒは炭素数が１８〜３５のアルキル基、

Here, R is an alkyl group having 18 to 35 carbon atoms,

（式中、Ｒ^１は炭素数が１８〜３５のアルキル基を表す。）を表す。
−Ｘ−は−ＣＨ_２−、−ＣＯ_２−、−ＣＯ−、−Ｏ−、−ＣＯＮＨ−、−ＣＯＮＲ^２−（式中、Ｒ^２は炭素数が１８〜３５のアルキル基を表す。）、−ＳＯ_２−、−ＳＯ_３−またはＳＯ_２ＮＨ−を表し、ｎは２または３の整数を表す。

(Wherein R ¹ represents an alkyl group having 18 to 35 carbon atoms).
-X- is _{-CH 2 -, - CO 2 -} , - CO -, - O -, - CONH -, - CONR 2 - ( wherein, ^{R 2} has a carbon number represents an alkyl group of 18 to 35.) _{, -SO 2 -, - SO 3} - or _SO 2 NH- represents, n represents an integer of 2 or 3.

  When the heat-sensitive recording layer of the present invention contains a metal chelate-type color-forming component containing the electron acceptor and the electron donor as main components, the print density and the print runnability by a thermal printer are excellent, and the resistance to plasticizers and oils is high. It is possible to obtain an excellent thermal recording material having image stability.

The higher fatty acid metal salt used as an electron acceptor in the present invention is a higher fatty acid single salt having a saturated or unsaturated aliphatic group having 16 to 35 carbon atoms, or 2 having a saturated or unsaturated aliphatic group having 16 to 35 carbon atoms. It is a higher fatty acid double salt containing more than one kind of metal.
The higher fatty acid metal salt of the present invention is an alkali metal salt of a higher fatty acid having a saturated or unsaturated aliphatic group having 16 to 35 carbon atoms or a higher fatty acid having a saturated or unsaturated aliphatic group having 16 to 35 carbon atoms. It can be obtained by reacting the ammonium salt with an inorganic metal salt containing a desired metal. A higher fatty acid metal double salt containing two or more kinds of metals can be obtained by the same method, but it can be obtained by using two or more kinds of inorganic metal salts in combination. Therefore, it is possible to control freely the kind of metal atom in double salt, and its mixing ratio by adjusting when making it react. For example, by reacting an aqueous solution of sodium behenate with a mixed aqueous solution of ferric chloride and zinc chloride having a molar ratio of 2: 1, an iron / zinc double salt containing iron and zinc in a ratio of 2: 1 is obtained. can get.
As the metal contained in the higher fatty acid metal salt of the present invention, polyvalent metals other than alkali metals, such as iron, zinc, calcium, magnesium, aluminum, barium, lead, manganese, tin, nickel, cobalt, copper, silver, Examples include mercury. Iron, zinc, calcium, aluminum, magnesium and silver are preferable.

  Specific examples of the higher fatty acid metal salt of the present invention include iron stearate, iron behenate, iron montanate, iron stearate / zinc double salt, iron montanate / zinc double salt, iron behenate / zinc double salt Salt, iron behenate / calcium double salt, iron behenate / aluminum double salt, iron / magnesium double salt behenate, silver behenate / calcium double salt, silver behenate / aluminum double salt, silver behenate / magnesium double salt, Examples include calcium behenate / aluminum double salt, but are not limited thereto. These higher fatty acid metal salts may be used alone or in combination of two or more.

  The polyvalent hydroxyaromatic compound used as an electron donor in the present invention is represented by the following general formula (Formula 1).

ここで、Ｒは炭素数が１８〜３５のアルキル基、

Here, R is an alkyl group having 18 to 35 carbon atoms,

（式中、Ｒ^１は炭素数が１８〜３５のアルキル基を表す。）を表す。
−Ｘ−は−ＣＨ_２−、−ＣＯ_２−、−ＣＯ−、−Ｏ−、−ＣＯＮＨ−、−ＣＯＮＲ^２−（式中、Ｒ^２は炭素数が１８〜３５のアルキル基を表す。）、−ＳＯ_２−、−ＳＯ_３−またはＳＯ_２ＮＨ−を表し、ｎは２または３の整数を表す。

(Wherein R ¹ represents an alkyl group having 18 to 35 carbon atoms).
-X- is _{-CH 2 -, - CO 2 -} , - CO -, - O -, - CONH -, - CONR 2 - ( wherein, ^{R 2} has a carbon number represents an alkyl group of 18 to 35.) _{, -SO 2 -, - SO 3} - or _SO 2 NH- represents, n represents an integer of 2 or 3.

  The polyvalent hydroxyaromatic compound of the present invention is usually used after being subjected to a dispersion treatment in an aqueous or solvent-based binder when preparing a coating solution for a thermosensitive recording layer. Since the polyvalent hydroxyaromatic compound of the present invention has 18 to 35 carbon atoms in the substituent other than the color-developing group and has 2 or 3 hydroxyl groups, the electron acceptor in preparing the coating liquid This is preferable because the reactivity of the coating liquid is low and unintentional coloring of the coating liquid is suppressed. Moreover, the stability in the dispersion process is good. The 2 or 3 hydroxyl groups are preferably adjacent to each other.

Specific examples of the polyvalent hydroxyaromatic compound of the present invention include the following, but are not limited thereto. Moreover, you may use these hydroxy aromatic compounds individually or in mixture of 2 or more types. In the following formula, R, R ¹ and R ² are defined in the same manner as described above.

The heat-sensitive recording layer of the present invention may contain a color developer other than the higher fatty acid metal salt as long as desired performance is not lost.
Examples of the developer other than the higher fatty acid metal salt used in the present invention include inorganic acidic substances such as activated clay, attapulgite, colloidal silica, and aluminum silicate, 4,4′-isopropylidenediphenol, 1,1-bis. (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 4,4′-dihydroxydiphenyl sulfide, hydroquinone monobenzyl ether, benzyl 4-hydroxybenzoate, 4,4 ′ -Dihydroxydiphenylsulfone, 2,4'-dihydroxydiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone, 4-hydroxy-4'-n-propoxydiphenylsulfone, bis (3-allyl-4-hydroxyphenyl) Sulfone, 4-hydroxy- '-Methyldiphenylsulfone, 4-hydroxyphenyl-4'-benzyloxyphenylsulfone, 3,4-dihydroxyphenyl-4'-methylphenylsulfone, 1- [4- (4-hydroxyphenylsulfonyl) phenoxy] -4- [4- (4-Isopropoxyphenylsulfonyl) phenoxy] butane, phenol condensation composition described in JP-A No. 2003-154760, aminobenzenesulfonamide derivative described in JP-A No. 8-59603, bis (4-hydroxyphenyl) Thioethoxy) methane, 1,5-di (4-hydroxyphenylthio) -3-oxapentane, butyl bis (p-hydroxyphenyl) acetate, methyl bis (p-hydroxyphenyl) acetate, 1,1-bis (4 -Hydroxyphenyl) -1-phenylethane, 1 4-bis [α-methyl-α- (4′-hydroxyphenyl) ethyl] benzene, 1,3-bis [α-methyl-α- (4′-hydroxyphenyl) ethyl] benzene, di (4-hydroxy- 3-methylphenyl) sulfide, 2,2′-thiobis (3-tert-octylphenol), 2,2′-thiobis (4-tert-octylphenol), phenols such as diphenylsulfone cross-linking compounds described in WO97 / 16420 Compounds, compounds described in WO02 / 081229 or JP2002-301873, thiourea compounds such as N, N′-di-m-chlorophenylthiourea, p-chlorobenzoic acid, bis [4- (n- Octyloxycarbonylamino) zinc salicylate] dihydrate, 4- [2- (p-methoxyphenoxy) ethyloxy] sa Lithic acid, 4- [3- (p-tolylsulfonyl) propyloxy] salicylic acid, 5- [p- (2-p-methoxyphenoxyethoxy) cumyl] salicylic acid aromatic carboxylic acids, and of these aromatic carboxylic acids Salts with polyvalent metal salts such as zinc, magnesium, aluminum, calcium, titanium, manganese, tin, nickel, etc. In addition, antipyrine complexes of zinc thiocyanate, complex zinc salts of terephthalaldehyde acid with other aromatic carboxylic acids, etc. Is mentioned. 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.

  When the heat-sensitive recording layer of the present invention contains a developer other than the higher fatty acid metal salt, the higher-grade fatty acid metal salt and the developer other than the higher fatty acid metal salt are used in a total of 100 parts by weight. The content of the fatty acid metal salt is preferably 10 parts by weight or more, more preferably 15 parts by weight or more, and particularly preferably 20 parts by weight or more and 50 parts by weight or less. If it exceeds 50 parts by weight, the effect of improving the image stability with respect to the plasticizer and oil is saturated and the printing density tends to decrease.

The heat-sensitive recording layer of the present invention may contain a leuco dye other than the polyvalent hydroxyaromatic compound as long as the desired performance is not lost.
As the leuco dye other than the polyvalent hydroxyaromatic compound 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. Of these, a fluorinated compound, a fluoran compound, a fluorene compound, a divinyl compound, and the like are preferable. Specific examples of typical colorless or light leuco dyes (dye precursors) are shown below. These dye precursors may be used alone or in combination of two or more.
<Triphenylmethane leuco dye>
3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as crystal violet lactone); 3,3-bis (p-dimethylaminophenyl) phthalide (also known as malachite green lactone)

<Fluoran leuco dye>
3-diethylamino-6-methylfluorane; 3-diethylamino-6-methyl-7-anilinofluorane; 3-diethylamino-6-methyl-7- (o, p-dimethylanilino) fluorane; 3-diethylamino- 6-methyl-7-chlorofluorane; 3-diethylamino-6-methyl-7- (m-trifluoromethylanilino) fluorane; 3-diethylamino-6-methyl-7- (o-chloroanilino) fluorane; Diethylamino-6-methyl-7- (p-chloroanilino) fluorane; 3-diethylamino-6-methyl-7- (o-fluoroanilino) fluorane; 3-diethylamino-6-methyl-7- (m-methylanilino) fluorane 3-diethylamino-6-methyl-7-n-octylanilinofluorane; 3-diethylamino-6-methyl-7-n-octylaminofluorane; 3-diethylamino-6-methyl-7-benzylaminofluorane; 3-diethylamino-6-methyl-7-dibenzylaminofluorane; 3-diethylamino-6-chloro-7-anilinofluorane; 3-diethylamino-6-chloro-7-p-methylanilinofluorane; 3-diethylamino-6 3-Ethoxyethyl-7-anilinofluorane; 3-diethylamino-7-methylfluorane; 3-diethylamino-7-chlorofluorane; 3-diethylamino-7- (m-trifluoromethylanilino) fluorane; Diethylamino-7- (o-chloroanilino) fluorane; 3-diethylamino 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-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 -Trifluoromethylanilino) fluorane; 3-di-n-pentylamino-6-chloro-7-anilinofluorane; 3-di-n-pentyl Mino-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-toludino)- 6-methyl-7-anilinofluorane; 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluorane; 3- (N-ethyl-N-isoamyl) Amino) -6-chloro-7-anilinofluorane; 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluorane; 3- (N-ethyl-N-isobutyl) Amino) -6-methyl-7-anilinofluorane; 3- (N-ethyl-N-ethoxypropylamino) -6-methyl-7-anilinofluorane; 3-cyclohexylamino-6-chlorofluorane; 2- (4-oxahexyl) -3-dimethylamino-6-methyl-7-anilinofluorane; 2- (4-oxahexyl) -3-diethylamino-6-methyl-7-anilinofluorane; 2 -(4-oxahexyl) -3-dipropylamino-6-methyl-7-anilinofluorane; 2-methyl-6-p- (p-dimethylaminophenyl) aminoani 2-methoxy-6-p- (p-dimethylaminophenyl) aminoanilinofluorane; 2-chloro-3-methyl-6-p- (p-phenylaminophenyl) aminoanilinofluorane; Chloro-6-p- (p-dimethylaminophenyl) aminoanilinofluorane; 2-nitro-6-p- (p-diethylaminophenyl) aminoanilinofluorane; 2-amino-6-p- (p- 2-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluorane; 2-phenyl-6-methyl-6-p- (p-phenylaminophenyl) aminoani Linofluorane; 2-benzyl-6-p- (p-phenylaminophenyl) aminoanilinofluorane; 2-hydroxy-6-p- (p-phenylaminophenyl) 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] -Fluoran

<Fluorene leuco dye>
3,6,6′-tris (dimethylamino) spiro [fluorene-9,3′-phthalide]; 3,6,6′-tris (diethylamino) spiro [fluorene-9,3′-phthalide]
<Divinyl leuco dye>
3,3-bis- [2- (p-dimethylaminophenyl) -2- (p-methoxyphenyl) ethenyl] -4,5,6,7-tetrabromophthalide; 3,3-bis- [2- (P-dimethylaminophenyl) -2- (p-methoxyphenyl) ethenyl] -4,5,6,7-tetrachlorophthalide; 3,3-bis- [1,1-bis (4-pyrrolidinophenyl) ) Ethylene-2-yl] -4,5,6,7-tetrabromophthalide; 3,3-bis- [1- (4-methoxyphenyl) -1- (4-pyrrolidinophenyl) ethylene-2- Yl] -4,5,6,7-tetrachlorophthalide

<Others>
3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide; 3- (4-diethylamino-2-ethoxyphenyl) -3- ( 1-octyl-2-methylindol-3-yl) -4-azaphthalide; 3- (4-cyclohexylethylamino-2-methoxyphenyl) -3- (1-ethyl-2-methylindol-3-yl)- 4-Azaphthalide; 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide; 3,6-bis (diethylamino) fluorane-γ- (3′-nitro) anilinolactam; -Bis (diethylamino) fluorane-γ- (4'-nitro) anilinolactam; 1,1-bis- [2 ', 2', 2 ", 2" -tetrakis- (p-dimethyla Nophenyl) -ethenyl] -2,2-dinitrileethane; 1,1-bis- [2 ′, 2 ′, 2 ″, 2 ″ -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2- β-naphthoylethane; 1,1-bis- [2 ′, 2 ′, 2 ″, 2 ″ -tetrakis- (p-dimethylaminophenyl) -ethenyl] -2,2-diacetylethane; bis- [2, 2,2 ′, 2′-Tetrakis- (p-dimethylaminophenyl) -ethenyl] -methylmalonic acid dimethyl ester

  When the heat-sensitive recording layer of the present invention contains a leuco dye other than the polyvalent hydroxyaromatic compound, the total amount of the polyvalent hydroxyaromatic compound and the leuco dye other than the polyvalent hydroxyaromatic compound is 100 parts by weight. On the other hand, the content of the polyvalent hydroxyaromatic compound is preferably 10 parts by weight or more, more preferably 15 parts by weight or more, and particularly preferably 20 parts by weight or more and 50 parts by weight or less. If it exceeds 50 parts by weight, the effect of improving the image stability with respect to the plasticizer and oil is saturated and the printing density tends to decrease.

  Examples of the sensitizer used in the present invention include fatty acid amides such as diphenylsulfone, stearamide, and palmitic acid amide, benzyloxynaphthalene, 1,2-di- (3-methylphenoxy) ethane, dioxalate (p- Examples thereof include, but are not limited to, methylbenzyl). These sensitizers may be used alone or in combination of two or more.

Examples of the binder used in the present invention include the above-mentioned acrylic resins, fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, carboxyl-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, and terminal alkyl-modified polyvinyl alcohol. , Cellulose ethers such as hydroxyethylcellulose, methylcellulose, ethylcellulose, carboxymethylcellulose, acetylcellulose and derivatives thereof, starch, enzyme-modified starch, thermochemically modified starch, oxidized starch, esterified starch, etherified starch (for example, hydroxyethylated starch) Etc.), starches such as cationized starch, polyacrylamide, cationic polyacrylamide, anionic polyacrylamide Polyacrylamides such as amphoteric polyacrylamide, polyester polyurethane resins, polyether polyurethane resins, urethane resins such as polyurethane ionomer resins, styrene-butadiene copolymers, styrene-butadiene-acrylonitrile copolymers, styrene-butadiene- Styrene-butadiene resin such as acrylic copolymer, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, polyacrylic ester, arabic rubber, polyvinyl butyral, polystyrose and their co-polymers Examples include coalescence, silicone resin, petroleum resin, terpene resin, ketone resin, coumarone resin, and the like. These may be used in combination.
The binder used in the present invention is preferably an emulsion or latex of the urethane-based resin or styrene-butadiene-based resin in order to improve the adhesiveness and tackiness to the plastic film.

  Examples of the crosslinking agent used in the present invention include glyoxal, methylol melamine, melamine formaldehyde resin, melamine urea resin, polyamine epichlorohydrin resin, polyamide epichlorohydrin resin, potassium persulfate, ammonium persulfate, sodium persulfate, chloride chloride Examples include ferric iron, magnesium chloride, borax, boric acid, alum, ammonium chloride and the like.

Examples of the lubricant used in the present invention include fatty acid metal salts such as zinc stearate and calcium stearate, waxes, and silicone resins.
In addition, as an image stabilizer showing the oil resistance effect of a recorded image, 4,4′-butylidene (6-tert-butyl-3-methylphenol), 2,2′-di-tert-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, 4-benzyloxy-4 '-(2,3-epoxy-2-methylpropoxy) diphenylsulfone, 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 metal chelate color forming component used in the present invention, that is, the higher fatty acid metal salt that is an electron acceptor, the polyvalent hydroxyaromatic compound that is an electron donor, a developer other than the higher fatty acid metal salt, Kinds and amounts of leuco dyes other than polyvalent aromatic compounds, sensitizers, and other various components are determined according to the required performance and recording suitability, and are not particularly limited. Usually, the total of the higher fatty acid metal salt and the developer other than the higher fatty acid metal salt is 0.1% in total with respect to 1 part by weight of the polyvalent hydroxyaromatic compound and the leuco dye other than the polyvalent hydroxyaromatic compound. 1 to 10 parts by weight, 0.5 to 20 parts by weight of pigment, 0.1 to 10 parts by weight of sensitizer, 0.01 to 10 parts by weight of stabilizer, and 0.01 to 10 parts by weight of other components are used. , Ba Nda is suitably heat-sensitive recording layer solid content of about 5 to 50 wt%.

  The metal chelate-type color forming component used in the present invention, the leuco dye other than the polyvalent hydroxyaromatic compound, the color developer other than the higher fatty acid metal salt, and the material to be added as required are ball mill, attritor, sand glider Then, the mixture is pulverized to a particle size of several microns or less with a pulverizer or a suitable emulsifier, and various additives are added according to the binder and purpose to obtain a coating solution. As the solvent used in the coating liquid, water, alcohol or the like can be used, and its solid content is about 20 to 40% by weight.

By applying the coating liquid onto a support of a plastic film, a desired heat-sensitive recording material can be obtained.
Coating methods for each layer include air knife method, rod blade method, vent blade method, bevel blade method, roll method, slot type curtain method, slide type curtain method, slide hopper type curtain method, bead type curtain method, spray method The die method and the like can be exemplified, and these coating methods are appropriately selected and used.
The coating amount of the heat-sensitive recording layer is usually 2 to 10 g / ^{m 2} approximately, the coating amount of the protective layer is usually 1 to 5 g / ^{m 2} approximately.
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 following examples illustrate the invention but are not intended to limit the invention. In the description, parts and% represent parts by weight and% by weight, respectively.
First, a developer other than the higher fatty acid metal salt dispersions 1-2 (A1 liquid, A2 liquid), polyvalent hydroxyaromatic compound dispersions 1-2 (B1 liquid, B2 liquid), and higher fatty acid metal salts with the following composition: Disperse the dispersion (liquid C), the leuco dye dispersion liquid (liquid D) other than the polyvalent hydroxyaromatic compound, and the sensitizer dispersion liquid (liquid E) individually with an average particle size of 0.5 microns using a sand grinder. Wet grinding was performed until
Higher fatty acid metal salt dispersion 1 (A1)
Iron and zinc behenate double salt (metal molar ratio in higher fatty acid metal double salt 2: 1)
(Asahi Denka Kogyo Co., Ltd., trade name: DM-1022) 6.0 parts polyvinyl alcohol 10% aqueous solution 5.0 parts water 1.5 parts Higher fatty acid metal salt dispersion 2 (A2 liquid)
Iron / calcium stearate double salt (metal molar ratio in higher fatty acid metal double salt 2: 1) 6.0 parts Polyvinyl alcohol 10% aqueous solution 5.0 parts Water 1.5 parts

Polyhydroxy aromatic compound dispersion 1 (B1 solution)
Stearyl gallate compound (Dainippon Pharmaceutical Co., Ltd.,
Product name: TH-S) ^* 6.0 parts polyvinyl alcohol 10% aqueous solution 5.0 parts water 1.5 parts * TH-S is represented by the following formula.

多価ヒドロキシ芳香族化合物分散液２（Ｂ２液）
下式（化７）で表される化合物 ６．０部
ポリビニルアルコール １０％水溶液 ５．０部
水 １．５部

Polyvalent hydroxy aromatic compound dispersion liquid 2 (B2 liquid)
Compound represented by the following formula (Chemical Formula 7) 6.0 parts Polyvinyl alcohol 10% aqueous solution 5.0 parts Water 1.5 parts

Developer dispersion liquid other than higher fatty acid metal salt (liquid C)
4-hydroxy-4'-isopropoxydiphenyl sulfone (manufactured by Nippon Soda Co., Ltd., trade name: D-8) 3.0 parts polyvinyl alcohol 10% aqueous solution 6.9 parts water 5.6 parts Other than polyvalent hydroxy aromatic compounds Leuco dye dispersion (liquid D)
3-Dibutylamino-6-methyl-7-anilinofluorane (manufactured by Yamamoto Kasei Co., Ltd., trade name: ODB2) 3.0 parts Polyvinyl alcohol 10% aqueous solution 6.9 parts Water 3.9 parts Sensitizer dispersion ( E liquid)
Oxalate bis (p-methylbenzyl) (Dainippon Ink,
Product name: HS3520) 1.5 parts polyvinyl alcohol 10% aqueous solution 4.7 parts water 2.8 parts

Subsequently, the dispersion liquid was mixed at the following ratio to prepare a thermal recording layer coating solution.
<Thermosensitive recording layer coating solution 1 (hereinafter referred to as “SBR formulation 1”)>
Higher fatty acid metal salt dispersion liquid 1 (A1 liquid) 6.0 parts Multivalent hydroxyaromatic compound dispersion liquid 1 (B1 liquid) 6.0 parts Developer dispersion liquid (liquid C) other than the higher fatty acid metal salt 21.0 Parts leuco dye dispersion liquid other than polyvalent hydroxyaromatic compound (liquid D) 16.0 parts sensitizer dispersion liquid (liquid E) 9.0 parts styrene / butadiene copolymer latex (solid content 48%) 16.0 Sodium dioctylsulfosuccinate (manufactured by Kao Corporation,
Product name: Perex OT-P, solid content 70%) 0.15 parts Water 15.0 parts <Coating liquid 2 for thermosensitive recording layer (hereinafter referred to as “PVA formulation”)>
Higher fatty acid metal salt dispersion liquid 1 (A1 liquid) 6.0 parts Multivalent hydroxyaromatic compound dispersion liquid 1 (B1 liquid) 6.0 parts Developer dispersion liquid (liquid C) other than the higher fatty acid metal salt 21.0 Parts leuco dye dispersion liquid other than polyvalent hydroxy aromatic compound (liquid D) 16.0 parts sensitizer dispersion liquid (liquid E) 9.0 parts fully saponified polyvinyl alcohol aqueous solution (manufactured by Kuraray Co., Ltd.,
Product name: PVA117, solid content 12%) 25.0 parts <Coating liquid 3 for thermosensitive recording layer (hereinafter referred to as “SBR prescription 2”)>
Higher fatty acid metal salt dispersion liquid 2 (A2 liquid) 6.0 parts Multivalent hydroxyaromatic compound dispersion liquid 1 (B1 liquid) 6.0 parts Developer dispersion liquid (liquid C) other than the higher fatty acid metal salt 21.0 Parts leuco dye dispersion liquid other than polyvalent hydroxyaromatic compound (liquid D) 16.0 parts sensitizer dispersion liquid (liquid E) 9.0 parts styrene / butadiene copolymer latex (solid content 48%) 16.0 Sodium dioctylsulfosuccinate (manufactured by Kao Corporation,
Product name: Perex OT-P, solid content 70%) 0.15 parts Water 15.0 parts <Coating liquid 4 for heat-sensitive recording layer (hereinafter referred to as “SBR prescription 3”)>
Higher fatty acid metal salt dispersion liquid 1 (A1 liquid) 6.0 parts Multivalent hydroxyaromatic compound dispersion liquid 2 (B2 liquid) 6.0 parts Developer dispersion liquid (liquid C) other than the higher fatty acid metal salt 21.0 Parts leuco dye dispersion liquid other than polyvalent hydroxyaromatic compound (liquid D) 16.0 parts sensitizer dispersion liquid (liquid E) 9.0 parts styrene / butadiene copolymer latex (solid content 48%) 16.0 Sodium dioctylsulfosuccinate (manufactured by Kao Corporation,
Product name: Perex OT-P, solid content 70%) 0.15 parts Water 15.0 parts <Coating liquid 5 for thermosensitive recording layer (hereinafter referred to as “SBR prescription 4”)>
Higher fatty acid metal salt dispersion liquid 2 (A2 liquid) 6.0 parts Multivalent hydroxyaromatic compound dispersion liquid 2 (B2 liquid) 6.0 parts Developer dispersion liquid (liquid C) other than the higher fatty acid metal salt 21.0 Parts leuco dye dispersion liquid other than polyvalent hydroxyaromatic compound (liquid D) 16.0 parts sensitizer dispersion liquid (liquid E) 9.0 parts styrene / butadiene copolymer latex (solid content 48%) 16.0 Sodium dioctylsulfosuccinate (manufactured by Kao Corporation,
Product name: Perex OT-P, solid content 70%) 0.15 parts Water 15.0 parts <Coating liquid 6 for heat-sensitive recording layer (hereinafter referred to as “SBR prescription 5”)>
Higher fatty acid metal salt dispersion liquid 1 (A1 liquid) 3.0 parts Multivalent hydroxyaromatic compound dispersion liquid 1 (B1 liquid) 3.0 parts Developer dispersion liquid (liquid C) other than the higher fatty acid metal salt 28.4 Parts leuco dye dispersion liquid other than polyvalent hydroxy aromatic compound (liquid D) 23.4 parts sensitizer dispersion liquid (liquid E) 9.0 parts styrene / butadiene copolymer latex (solid content 48%) 16.0 Sodium dioctylsulfosuccinate (manufactured by Kao Corporation,
Product name: Perex OT-P, solid content 70%) 0.15 parts Water 15.0 parts <Coating liquid 7 for heat-sensitive recording layer (hereinafter referred to as “SBR formulation 6”)>
Higher fatty acid metal salt dispersion liquid 1 (A1 liquid) 1.8 parts Multivalent hydroxyaromatic compound dispersion liquid 1 (B1 liquid) 1.8 parts Developer dispersion liquid (liquid C) other than the higher fatty acid metal salt 31.4 Parts leuco dye dispersion liquid other than polyvalent hydroxy aromatic compound (liquid D) 26.4 parts sensitizer dispersion liquid (liquid E) 9.0 parts styrene-butadiene copolymer latex (solid content 48%) 16.0 Sodium dioctylsulfosuccinate (manufactured by Kao Corporation,
Product name: Perex OT-P, solid content 70%) 0.15 parts Water 15.0 parts <Coating liquid 8 for heat-sensitive recording layer (hereinafter referred to as “SBR formulation 7”)>
Developer dispersion liquid other than higher fatty acid metal salt (liquid C) 35.9 parts Leuco dye dispersion liquid other than polyvalent hydroxyaromatic compound (liquid D) 30.9 parts Sensitizer dispersion liquid (liquid E) 9. 0 parts Styrene-butadiene copolymer latex (solid content 48%) 16.0 parts Sodium dioctyl sulfosuccinate (manufactured by Kao Corporation,
Product name: Perex OT-P, solid content 70%) 0.15 parts water 15.0 parts

Subsequently, the composition which consists of the following ratio was mixed and it was set as the coating liquid for protective layers.
<Protective layer coating solution 1>
Non-core shell acrylic resin emulsion (Mitsui Chemicals,
Product name: ASN1004K, Tg 55 ° C., solid content 18%) 24.0 parts Self-emulsifying polyolefin resin emulsion (manufactured by Sumitomo Seika Co., Ltd.,
Product name: Saixen-A-GH, solid content 24.4%) 3.0 parts Zinc stearate (manufactured by Chukyo Yushi Co., Ltd., product name: Hydrin L536,
(Solid content 40%) 4.0 parts sodium dioctylsulfosuccinate (manufactured by Kao Corporation)
(Product name: Perex OT-P, solid content 70%) 0.07 parts Water 30.0 parts <Coating liquid 2 for protective layer>
Non-core shell acrylic resin emulsion (Mitsui Chemicals,
Product name: ASN1004K, Tg55 ° C., solid content 18%) 24.0 parts Self-emulsifying polyolefin resin emulsion (manufactured by Sumitomo Seika Co., Ltd.,
Product name: Saixen-AC, solid content 30.0%) 2.5 parts Zinc stearate (manufactured by Chukyo Yushi Co., Ltd., product name: Hydrin L536,
(Solid content 40%) 4.0 parts sodium dioctylsulfosuccinate (manufactured by Kao Corporation)
Product name: Perex OT-P, solid content 70%) 0.07 parts Water 30.0 parts <Coating liquid 3 for protective layer>
Completely saponified polyvinyl alcohol aqueous solution (Kuraray Co., Ltd.,
Product name: PVA117, solid content 12%) 42.0 parts Glyoxal (40% aqueous solution) 5.0 parts Zinc stearate (manufactured by Chukyo Yushi Co., Ltd., trade name: Hydrin L536,
40% solids) 4.0 parts water 27.0 parts

[Example 1]
On a polyethylene terephthalate film (manufactured by Teijin Ltd., Teijin Tetron 330, thickness 38 μm, total light transmittance 82%, hereinafter referred to as “PET film”), the thermal recording layer coating liquid 1 (SBR formulation 1) was dried. After coating and drying so that the coating amount is 5.0 g / m ² , the coating liquid 1 for the protective layer is further coated and dried so that the coating amount after drying is 3.0 g / m ^2, and thermal recording is performed. The body was made.
[Example 2]
The same procedure as in Example 1 was conducted except that the PET film of Example 1 was replaced with a triacetyl cellulose film (Fuji Film, Fujitac, thickness 40 μm, total light transmittance 90%, hereinafter referred to as “TAC film”). A heat-sensitive recording material was produced.
[Example 3]
16.0 parts of the styrene / butadiene copolymer latex (solid content 48%) in the thermal recording layer coating liquid 1 (SBR formulation 1) is 6.0 parts of the styrene / butadiene copolymer latex (solid content 48%). And a self-emulsifying polyolefin resin emulsion (manufactured by Sumitomo Seika Co., Ltd., trade name: Syxen-A-GH, 24.4% solids) 15.0 parts in the same manner as in Example 1, Produced.
[Example 4]
A thermosensitive recording material was produced in the same manner as in Example 1 except that the protective layer coating solution 2 was used instead of the protective layer coating solution 1.

[Example 5]
Example 1 except that the non-core-shell type acrylic resin emulsion in the protective layer coating solution 1 was replaced with a non-core-shell type acrylic resin emulsion (manufactured by Mitsui Chemicals, trade name: XNP3, Tg 35 ° C., solid content 18%). A thermosensitive recording material was produced in the same manner as described above.
[Example 6]
22.0 parts of non-core-shell type acrylic resin emulsion in coating liquid 1 for protective layer is 22.0 parts of core-shell type acrylic resin (manufactured by Nippon Paint Co., Ltd., trade name: N-538, Tg 100 ° C., solid content 20%). A heat-sensitive recording material was produced in the same manner as in Example 1 except that it was replaced with.
[Example 7]
A thermosensitive recording material was prepared in the same manner as in Example 1 except that the blending parts of the non-core shell acrylic resin emulsion and the self-emulsifying polyolefin resin emulsion in the protective layer coating solution 1 were changed to 12.0 parts, respectively.
[Example 8]
Heat sensitive in the same manner as in Example 1 except that the blending part of the non-core shell acrylic resin emulsion in the protective layer coating liquid 1 was changed to 27.5 parts and the blending part of the self-emulsifying polyolefin resin emulsion was changed to 0.3 parts. A recording body was produced.

[Example 9]
A heat-sensitive recording material was prepared in the same manner as in Example 1 except that the heat-sensitive recording layer coating solution 1 (SBR formulation 1) was changed to the heat-sensitive recording layer coating solution 3 (SBR formulation 2).
[Example 10]
A heat-sensitive recording material was produced in the same manner as in Example 1 except that the heat-sensitive recording layer coating solution 1 (SBR formulation 1) was changed to the heat-sensitive recording layer coating solution 4 (SBR formulation 3).
[Example 11]
A heat-sensitive recording material was prepared in the same manner as in Example 1 except that the heat-sensitive recording layer coating solution 1 (SBR formulation 1) was changed to the heat-sensitive recording layer coating solution 5 (SBR formulation 4).
[Example 12]
A thermosensitive recording material was produced in the same manner as in Example 1 except that the thermosensitive recording layer coating solution 1 (SBR formulation 1) was changed to the thermosensitive recording layer coating solution 6 (SBR formulation 5).
[Example 13]
A heat-sensitive recording material was produced in the same manner as in Example 1 except that the heat-sensitive recording layer coating solution 1 (SBR formulation 1) was changed to the heat-sensitive recording layer coating solution 7 (SBR formulation 6).

[Comparative Example 1]
After coating and drying the thermal recording layer coating liquid 2 (PVA formulation) on a paper support (basic weight 60 g / m ² base paper) so that the coating amount after drying is 5.0 g / m ^2. Further, the protective layer coating liquid 3 was applied and dried so that the coating amount after drying was 3.0 g / m ² to prepare a heat-sensitive recording material.
[Comparative Example 2]
A thermosensitive recording material was produced in the same manner as in Example 1 except that the protective layer coating solution 3 was used instead of the protective layer coating solution 1. A photograph of the surface of the protective layer of the produced thermal recording material is shown in FIG.
[Comparative Example 3]
A heat-sensitive recording material was produced in the same manner as in Example 1 except that the protective layer was not provided.
[Comparative Example 4]
A thermosensitive recording material was produced in the same manner as in Example 1 except that the self-emulsifying polyolefin resin emulsion of the protective layer coating liquid 1 was not blended and the number of blended parts of the non-core shell acrylic resin emulsion was 27.5 parts. .
[Comparative Example 5]
A thermosensitive recording material was produced in the same manner as in Example 1 except that the non-core shell type acrylic resin emulsion of the coating liquid 1 for the protective layer was not blended, and the number of blended parts of the self-emulsifying polyolefin resin emulsion was 20.5 parts. .
[Comparative Example 6]
A heat-sensitive recording material was produced in the same manner as in Example 1 except that the heat-sensitive recording layer coating solution 1 (SBR formulation 1) was changed to the heat-sensitive recording layer coating solution 8 (SBR formulation 7).

The following evaluation was performed about the produced thermosensitive recording material.
<Print density>
Using the TH-PMD manufactured by Okura Electric Co., Ltd. (with a thermal recording paper printing tester and a Kyocera thermal head), the produced thermal recording material was solid printed at an applied energy of 0.42 mJ / dot and a printing speed of 50 mm / sec. did. The print density of the recording part was measured with a Macbeth densitometer (RD-914, using an amber filter).
<Coating defects>
About the produced thermal recording body, the coating defect (ripple shape) of the coating surface was visually evaluated on the following reference | standard.
A: Rippled coating defects are not seen.
○: There are almost no rippled coating defects.
Δ: Rippled coating defects are slightly seen.
X: Many rippled coating defects are seen.

<Water resistance>
The produced thermal recording material was immersed in water for 24 hours in an environment of 23 ° C. and 50% Rh, and then the state of the coating layer was visually observed.
(Double-circle): A crack and peeling are not seen.
○: Almost no cracking or peeling.
(Triangle | delta): A crack and peeling are seen slightly.
X: Many cracks and peeling are seen.
<Printability>
The produced thermosensitive recording medium was solid-printed with an applied energy of 0.20 mJ / dot under an environment of 0 ° C. using a printing tester (manufactured by Canon Inc., HT180). The printing state at this time was evaluated according to the following criteria. The fact that the outermost layer of the recording medium sticks to the head of the printing tester and cannot be partially printed is called “whiteout”, and the noise of the printing tester caused by the outermost layer sticking to the head of the printing tester Is called “noise”.
A: No whiteout occurs in the solid print portion and there is almost no noise.
○: No whiteout occurs in the solid print part, but a little noise is generated.
Δ: Some whitening occurs in the solid print portion, and a little noise is generated.
X: White spots frequently occur in the solid print portion, and noise is large.
<Plasticizer resistance>
Using the TH-PMD manufactured by Okura Electric Co., Ltd. (with a thermal recording paper printing tester and a Kyocera thermal head), the produced thermal recording material was solid printed at an applied energy of 0.42 mJ / dot and a printing speed of 50 mm / sec. did. A polyvinyl chloride wrap (manufactured by Mitsui Toatsu Co., Ltd., High Wrap KMA) is wrapped around a paper tube in a single layer, and the thermal recording material is placed on the paper tube so that the printed part is on the outer surface. It was wound around and fixed. After processing for 24 hours in an environment of 40 ° C. and 50% RH, the recording density of the printed portion was measured with a Macbeth densitometer (RD-914, using an amber filter), and the residual ratio was calculated from the values before and after the processing.
Residual rate (%) = (recording density after processing / recording density before processing) × 100
<Oil resistance>
Using the TH-PMD manufactured by Okura Electric Co., Ltd. (with a thermal recording paper printing tester and a Kyocera thermal head), the produced thermal recording material was solid printed at an applied energy of 0.42 mJ / dot and a printing speed of 50 mm / sec. did. A drop of salad oil is dropped on the printing area and left to stand for 3 days in an environment of 23 ° C. and 50% RH. After lightly wiping the salad oil with filter paper, the recording density of the printing area is measured using a Macbeth densitometer (RD-914, amber filter used). The residual rate was calculated from the values before and after the treatment.
Residual rate (%) = (recording density after processing / recording density before processing) × 100

The evaluation results are shown in Tables 1 and 2.

Claims (8)

A heat-sensitive recording layer comprising a colorless or light-colored electron-donating leuco dye and an electron-accepting developer on a plastic film, and a heat-sensitive recording material having a protective layer as an outermost layer on the heat-sensitive recording layer, the protective layer comprising: In addition to containing an acrylic resin and a polyolefin resin, the thermosensitive recording layer contains a metal chelate-type color-forming component containing an electron acceptor and an electron donor as main components, and the electron acceptor has 16 to 35 carbon atoms. A heat-sensitive recording material, which is a higher fatty acid metal salt having a saturated or unsaturated aliphatic group, and wherein the electron donor is a polyvalent hydroxyaromatic compound represented by the following general formula (Formula 1).

(Wherein R is an alkyl group having 18 to 35 carbon atoms,

(In the formula, ^{R 1} represents an alkyl group having a carbon number of 18 to 35.) Represent, _-X- is _{-CH 2 -, - CO 2 -} , - CO -, - O -, - CONH -, - CONR ² — (wherein R ² represents an alkyl group having 18 to 35 carbon atoms), —SO ₂ —, —SO ₃ — or SO ₂ NH—, and n represents an integer of 2 or 3 . ) The heat-sensitive recording material according to claim 1, wherein the polyolefin resin is an olefin / unsaturated carboxylic acid copolymer. The heat-sensitive recording material according to claim 1 or 2, wherein the acrylic resin is an acrylic resin having a glass transition point higher than 50 ° C and not higher than 95 ° C. The heat-sensitive recording material according to claim 1, wherein the acrylic resin is a non-core shell acrylic resin. The heat-sensitive recording material according to any one of claims 1 to 4, wherein a blending amount (solid content) of the polyolefin resin in the protective layer is 3 to 60% by weight. The heat-sensitive recording material according to any one of claims 1 to 5, wherein a blending amount (solid content) of the acrylic resin in the protective layer is 15 to 97% by weight. The heat-sensitive recording material according to any one of claims 1 to 6, wherein a blending weight ratio (solid content) of the polyolefin resin / acrylic resin is 3/97 to 50/50. The heat-sensitive recording material according to claim 1, wherein the heat-sensitive recording layer contains an emulsion or latex of a urethane resin or a styrene-butadiene resin.