JP2009083173A - Heat-sensitive recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-sensitive recording medium which is free from an improper suitability for reading bar codes with time, even in case the recording medium has been laid in a shelf for a long time under such a condition that it is in contact with a film, a synthetic leather, etc. or under high temperature and humidity conditions, and further, which shows excellent heat/plasticizer resistance in the imaging part. <P>SOLUTION: This heat-sensitive recording medium includes a heat-sensitive color developing layer containing a colorless or pale-color electron-donative leuco dye and an electron-receptive developer, formed on a support. In addition, the recording medium is characterized in that it contains a sulfonamide compound of a special structure as a first developer and a diphenylsulfone derivative of a special structure as a second developer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat-sensitive recording material utilizing a color development reaction between an electron-donating leuco dye and an electron-accepting developer, and more particularly to a heat-sensitive recording material excellent in plasticizer resistance and heat resistance of an image area.

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

JP-A-5-571 JP 2003-89273 A JP-A-8-333329 JP 2003-212841 A

However, as thermal recording media are often used in applications that are used in harsh environments such as gold voucher applications, image storability and barcode suitability that are higher than conventional ones are required. In the current situation, sufficient quality is not obtained with the conventional technology as described above.
Therefore, the present invention provides a heat-sensitive recording material excellent in storage stability (plasticizer resistance, heat resistance) of an image area, which does not cause a problem in bar code readability even in a harsh environment. Objective.

（式中、Ｒ^４は、炭素数が１〜１２の直鎖又は分岐の飽和又は不飽和炭化水素を表し、Ｒ^５〜Ｒ^１０は、それぞれ独立して、ハロゲン原子、又は炭素数が１〜１２のアルキル基若しくはアルケニル基を表し、ｐ、ｑ、ｒ、ｓ、ｔ及びｕはそれぞれ０〜４の整数を表し、ｏは０〜５の整数を表し、Ａは、それぞれ独立して、エーテル結合を有してもよい炭素数が１〜１２の直鎖又は分枝の飽和又は不飽和の炭化水素基を表す。）で表されるジフェニルスルホン誘導体を含有することを特徴とする感熱記録体である。 As a result of intensive studies, the present inventors have found that the above-described problems can be solved by including two specific types of color developer in the thermosensitive coloring layer, and have completed the present invention.
That is, the present invention is a heat-sensitive recording material provided with a heat-sensitive coloring layer containing a colorless or light-colored electron-donating leuco dye and an electron-accepting developer on a support, and the heat-sensitive coloring layer comprises The following general formula (chemical formula 1)
(R ¹ —SO ₂ NH— (CONH) _m — (C _a H _2a ) —R ² —) _n —R ³
(Wherein R ¹ represents a substituted or unsubstituted aryl group, m represents 0 or 1, a represents an integer of 0 to 3, R ² represents a substituted or unsubstituted arylene group, and n represents Represents an integer of 1 to 4, and R ³ represents a hydrogen atom, a hydroxyl group or a carboxyl group when n = 1, and a bivalent to tetravalent fat corresponding to n having 1 to 4 carbon atoms when n = 2 to 4. As a second electron-accepting developer, a sulfonamide compound represented by the following general formula:

(In the formula, R ⁴ represents a linear or branched saturated or unsaturated hydrocarbon having 1 to 12 carbon atoms, and R ^{5 to} R ¹⁰ each independently represent a halogen atom or a carbon number of 1 to 1; 12 represents an alkyl group or an alkenyl group, p, q, r, s, t and u each represent an integer of 0 to 4, o represents an integer of 0 to 5, and A independently represents an ether. A linear or branched saturated or unsaturated hydrocarbon group having 1 to 12 carbon atoms, which may have a bond, and a diphenylsulfone derivative represented by formula (1). It is.

Hereinafter, the present invention will be described in more detail.
The heat-sensitive recording material of the present invention comprises a heat-sensitive color developing layer provided on a support, and the heat-sensitive color developing layer contains a dye and two kinds of color developers.
The sulfonamide compound which is the first developer used in the present invention is represented by the following formula (Formula 1).
(R ¹ —SO ₂ NH— (CONH) _m — (C _a H _2a ) —R ² —) _n —R ³
Here, R ¹ represents a substituted or unsubstituted aryl group. As the aryl group, a phenyl group, an α or β naphthyl group is preferable. Examples of the substituent include an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, a hydroxyl group, a halogen atom, a vinyl group, and an allyl group. The number of substituents is 1 to 3, preferably 1.
R ¹ is preferably an aryl group represented by the following formula.

m represents 0 or 1;
a represents an integer of 0 to 3, preferably 0. _{Examples of} — (C _a H _2a ) — include —CH ₂ — and —CH ₂ CH ₂ —.
R ² represents a substituted or unsubstituted arylene group. As the arylene group, a phenylene group and a naphthylene group are preferable. As the substituent, a hydroxyl group, a carboxyl group, an alkyl group having 1 to 4 carbon atoms, and an alkoxyl group having 1 to 4 carbon atoms are preferable. The number of substituents is 1 to 3, preferably 1 or 2.
n represents an integer of 1 to 4.

R ³ represents a substituent or a linking group having a valence of n. That is, R ³ represents a hydrogen atom, a hydroxyl group or a carboxyl group when n = 1, and a divalent to tetravalent aliphatic group corresponding to n having 1 to 4 carbon atoms when n = 2 to 4. The aliphatic group may be saturated or unsaturated.
In the case of n = 1,-(C _a H _2a ) -R ² -R ³ is preferably a group of the following formula.

  Specific examples of this sulfonamide compound include N-phenyl-4-hydroxybenzenesulfonamide, bis (N-phenyl-N ′-(4-methylsulfonyl) urea) methane, N- (p-toluenesulfonyl)- N ′-(4-carboxy-3-hydroxyphenyl) urea, N- (p-toluenesulfonyl) -N ′-(4-hydroxyphenyl) urea, N- (p-toluenesulfonyl) -N ′-(4- Carboxy-2-hydroxyphenyl) urea, N- (p-toluenesulfonyl) -N ′-(3-carboxy-4-hydroxyphenyl) urea, N- (p-toluenesulfonyl) -N ′-(3-carboxy- 5-hydroxyphenyl) urea, N- (p-toluenesulfonyl) -N ′-(2-carboxy-4-hydroxyphenyl) Urea, N- (p-toluenesulfonyl) -N ′-(4-carboxy-5-hydroxy-3-methylphenyl) urea, N- (p-toluenesulfonyl) -N ′-(4-carboxy-5-hydroxy -3-chlorophenyl) urea, N- (p-toluenesulfonyl) -N ′-(4-carboxy-5-hydroxy-1-naphthyl) urea, benzenesulfonyl-N ′-(4-carboxy-3-hydroxyphenyl) Urea, o-toluenesulfonyl-N ′-(4-carboxy-3-hydroxyphenyl) urea, p-chlorosulfonyl-N ′-(4-carboxy-3-hydroxyphenyl) urea, p-methoxybenzenesulfonyl-N ′ -(4-carboxy-3-hydroxyphenyl) urea, N- (p-toluenesulfonyl) -N '-( '- carboxy-3'-hydroxybenzyl) urea, N-(p-toluenesulfonyl) -N' - (4'-carboxy-3'-hydroxy-phenethyl) urea, and the like.

ここで、Ｒ^４は、炭素数が１〜１２、好ましく１〜５、より好ましくは１〜４の直鎖又は分岐の飽和又は不飽和炭化水素を表すが、飽和炭化水素基としては、例えば、メチル、エチル、ｎ−プロピル、イソプロピル、ｎ−ブチル、ｔ−ブチル、イソアミル等が挙げられる。また、不飽和炭化水素基の炭素数は好ましくは２〜５であり、不飽和炭化水素基として、例えば、エチレン、1−ｎ−プロピレン、２−ｎ−プロピレン、イソプロピレン、１−ｎ−ブチレン、２−ｎ−ブチレン、３−ｎ−ブチレン等が挙げられる。 The diphenylsulfone derivative which is the second developer used in the present invention is represented by the following formula.

Here, R ⁴ represents a linear or branched saturated or unsaturated hydrocarbon having 1 to 12, preferably 1 to 5, and more preferably 1 to 4 carbon atoms. As the saturated hydrocarbon group, for example, Examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, isoamyl and the like. The unsaturated hydrocarbon group preferably has 2 to 5 carbon atoms, and examples of the unsaturated hydrocarbon group include ethylene, 1-n-propylene, 2-n-propylene, isopropylene, and 1-n-butylene. , 2-n-butylene, 3-n-butylene and the like.

R ^{5 to} R ¹⁰ each independently represent a halogen atom, or an alkyl or alkenyl group having 1 to 12 carbon atoms, and examples of the halogen atom include chlorine, bromine, fluorine, and iodine. Bromine is preferred.
The alkyl group of R ^{5 to} R ¹⁰ is a linear or branched saturated hydrocarbon having 1 to 12, preferably 1 to 5, and more preferably 1 to 4 carbon atoms, and examples thereof include a methyl group, an ethyl group, and n- Propyl group, isopropyl group, n-butyl group, t-butyl group, n-pentyl group, isopentyl group, neopentyl group, t-pentyl group, n-hexyl group, isohexyl group, 1-methylpentyl group, 2-methylpentyl group Groups and the like.
The alkenyl group of R ^{5 to} R ¹⁰ is a linear or branched unsaturated hydrocarbon having 2 to 12 carbon atoms, such as a vinyl group, an allyl group, an isopropenyl group, a 1-propenyl group, or a 2-butenyl group. , 3-butenyl group, 1,3-butanedienyl group, 2-methyl-2-propenyl group and the like, among which vinyl group and allyl group are preferable.

p, q, r, s, t and u each represent an integer of 0 to 4, preferably 0 to 2, and more preferably 0. However, when p, q, r, s, t, and u are 2 to 4, R ^{5 to} R ¹⁰ may be the same or different, and the same is preferable.

Each A independently represents a straight-chain or branched saturated or unsaturated hydrocarbon group having 1 to 12 carbon atoms which may have an ether bond, but has a straight-chain ether bond. The saturated hydrocarbon which may be sufficient is preferable, and the saturated hydrocarbon which does not have a linear ether bond is still more preferable.
Examples of the saturated hydrocarbon group for A include linear or branched saturated hydrocarbons having 1 to 12, preferably 2 to 6, and more preferably 3 to 4 carbon atoms.
Specific examples of saturated hydrocarbon groups include methylene, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, decamethylene, undecamethylene, Dodecamethylene group, methylmethylene group, dimethylmethylene group, methylethylene group, methyleneethylene group, ethylethylene group, 1,2-dimethylethylene group, 1-methyltrimethylene group, 1-methyltetramethylene group, 1,3- Examples thereof include dimethyltrimethylene group and 1-ethyl-4-methyl-tetramethylene group. Among them, saturated hydrocarbons having 2 to 6 carbon atoms such as ethylene group, trimethylene group, tetramethylene group, pentamethylene group and hexamethylene group. Groups are preferred.
Examples of the unsaturated hydrocarbon group for A include linear or branched unsaturated hydrocarbons having 1 to 12, preferably 2 to 6, and more preferably 2 to 4 carbon atoms. Specific examples of the unsaturated hydrocarbon group include a vinylene group, an ethynylene group, a propenylene group, a 2-butenylene group, a 2-butynylene group, and a 1-vinylethylene group. Among them, a propenylene group, a 2-butenylene group, etc. Aromatic hydrocarbon groups are preferred.
Examples of the hydrocarbon group having an ether bond include an ethyleneoxyethylene group, a tetramethyleneoxytetramethylene group, an ethyleneoxyethyleneoxyethylene group, an ethyleneoxymethyleneoxyethylene group, and a 1,3-dioxane-5,5-bismethylene group. Among them, ethyleneoxyethylene group and ethyleneoxyethyleneoxyethylene group are preferable.

Although o represents the integer of 0-5, Preferably it is 0-2, More preferably, it is 0.
The diphenylsulfone derivative may be a compound having a specific o in the general formula (Chemical Formula 2), or may be a mixture of any ratio of compounds having different o in the general formula (Chemical Formula 2).

Examples of the diphenylsulfone derivative represented by the general formula (Chemical Formula 2) include the following compounds, but are not limited thereto.
1- [4- (4-hydroxyphenylsulfonyl) phenoxy] -2- [4- (4-isopropoxyphenylsulfonyl) phenoxy] ethane, 1- [4- (4-hydroxyphenylsulfonyl) phenoxy] -3- [ 4- (4-Isopropoxyphenylsulfonyl) phenoxy] propane, 1- [4- (4-hydroxyphenylsulfonyl) phenoxy] -4- [4- (4-isopropoxyphenylsulfonyl) phenoxy] butane, 1- [4 -(4-Hydroxyphenylsulfonyl) phenoxy] -5- [4- (4-isopropoxyphenylsulfonyl) phenoxy] pentane, 1- [4- (4-hydroxyphenylsulfonyl) phenoxy] -6- [4- (4 -Isopropoxyphenylsulfonyl) phenoxy] hexane, 1- [4- 4-hydroxyphenylsulfonyl) phenoxy] -7- [4- (4-isopropoxyphenylsulfonyl) phenoxy] heptane, 1- [4- (4-hydroxyphenylsulfonyl) phenoxy] -8- [4- (4-iso Propoxyphenylsulfonyl) phenoxy] octane, 4- (4- [4- (4-hydroxyphenylsulfonyl) phenoxy] butoxy) -4 ′-(4- [4- (4-methoxyphenylsulfonyl) phenoxy] butoxy) diphenylsulfone 4- (4- (2- (4- (4- (2- (4- (4- (2- (4- (4-methoxyphenylsulfonyl) phenoxy) butoxy) phenylsulfonyl) phenoxy) butoxy) phenylsulfonyl) ) Phenoxy) butoxy) phenylsulfonyl) phenol and the like. Among these, 1- (4- (4-hydroxyphenylsulfonyl) phenoxy) -4- (4- (4-isopropoxyphenylsulfonyl) phenoxy) butane is preferable from the viewpoint of the balance between color development sensitivity and storage stability.

  In the present invention, other color developers may be used in combination as long as the effects of the present invention are not impaired. As such a developer, any known developer in the field of conventional pressure-sensitive or thermal recording paper can be used, and is not particularly limited. For example, activated clay, attapulgite, colloidal silica, silica Inorganic acidic substances such as aluminum, 4,4′-isopropylidenediphenol, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 4,4 '-Dihydroxydiphenyl sulfide, hydroquinone monobenzyl ether, benzyl 4-hydroxybenzoate, 4,4'-dihydroxydiphenylsulfone, 2,4'dihydroxydiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone, 4-hydroxy -4'-n-propoxydiphenylsulfo Bis (3-allyl-4-hydroxyphenyl) sulfone, 4-hydroxy-4'-methyldiphenylsulfone, 4-hydroxyphenyl-4'-benzyloxyphenylsulfone, 3,4-dihydroxyphenyl-4'-methyl Phenylsulfone, aminobenzenesulfonamide derivatives described in JP-A-8-59603, bis (4-hydroxyphenylthioethoxy) methane, 1,5-di (4-hydroxyphenylthio) -3-oxapentane, bis (p -Hydroxyphenyl) butyl acetate, methyl bis (p-hydroxyphenyl) acetate, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,4-bis [α-methyl-α- (4′- Hydroxyphenyl) ethyl] benzene, 1,3-bis [α-methyl-α- (4′-hydride) Xylphenyl) ethyl] benzene, di (4-hydroxy-3-methylphenyl) sulfide, 2,2′-thiobis (3-tert-octylphenol), 2,2′-thiobis (4-tert-octylphenol), international publication WO02 / 081229 or JP-A-2002-301873, thiourea compounds such as N, N′-di-m-chlorophenylthiourea, p-chlorobenzoic acid, stearyl gallate, bis [4- (n- Octyloxycarbonylamino) zinc salicylate] dihydrate, 4- [2- (p-methoxyphenoxy) ethyloxy] salicylic acid, 4- [3- (p-tolylsulfonyl) propyloxy] salicylic acid, 5- [p- ( 2-p-methoxyphenoxyethoxy) cumyl] salicylic acid aromatic carboxylic acid, and Salts of these aromatic carboxylic acids with polyvalent metal salts such as zinc, magnesium, aluminum, calcium, titanium, manganese, tin and nickel, as well as antipyrine complexes of zinc thiocyanate, terephthalaldehyde acid and other aromatics Examples include composite zinc salts with carboxylic acids. These developers can be used alone or in combination of two or more. A metal chelate color-developing component such as a higher fatty acid metal double salt and a polyvalent hydroxyaromatic compound described in JP-A No. 10-258577 can also be contained.

As the dye used in the present invention, any known dyes in the field of conventional pressure-sensitive or thermal recording paper can be used, and are not particularly limited, but include triphenylmethane compounds, fluorane compounds, fluorene compounds. , Divinyl compounds and the like are preferable. Specific examples of typical colorless or light-colored dyes (dye precursors) are shown below. These dye precursors may be used alone or in combination of two or more.
<Triphenylmethane leuco dye>
3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as crystal violet lactone); 3,3-bis (p-dimethylaminophenyl) phthalide (also known as malachite green lactone)

<Fluoran leuco dye>
3-diethylamino-6-methylfluorane; 3-diethylamino-6-methyl-7-anilinofluorane; 3-diethylamino-6-methyl-7- (o, p-dimethylanilino) fluorane; 3-diethylamino- 6-methyl-7-chlorofluorane; 3-diethylamino-6-methyl-7- (m-trifluoromethylanilino) fluorane; 3-diethylamino-6-methyl-7- (o-chloroanilino) fluorane; Diethylamino-6-methyl-7- (p-chloroanilino) fluorane; 3-diethylamino-6-methyl-7- (o-fluoroanilino) fluorane; 3-diethylamino-6-methyl-7- (m-methylanilino) fluorane 3-diethylamino-6-methyl-7-n-octylanilinofluorane; 3-diethylamino-6-methyl-7-n-octylaminofluorane; 3-diethylamino-6-methyl-7-benzylaminofluorane; 3-diethylamino-6-methyl-7-dibenzylaminofluorane;
3-diethylamino-6-chloro-7-methylfluorane; 3-diethylamino-6-chloro-7-anilinofluorane; 3-diethylamino-6-chloro-7-p-methylanilinofluorane; 3-diethylamino -6-ethoxyethyl-7-anilinofluorane; 3-diethylamino-7-methylfluorane; 3-diethylamino-7-chlorofluorane; 3-diethylamino-7- (m-trifluoromethylanilino) fluorane; 3-diethylamino-7- (o-chloroanilino) fluorane; 3-diethylamino-7- (p-chloroanilino) fluorane; 3-diethylamino-7- (o-fluoroanilino) fluorane; 3-diethylamino-benzo [a] fluorane ;
3-dibutylamino-6-methyl-7- (o); 3-dibutylamino-6-methyl-7- (o; 3-dibutylamino-6-methyl-7- (o , P-dimethylanilino) fluorane; 3-dibutylamino-6-methyl-7- (o-chloroanilino) fluorane; 3-dibutylamino-6-methyl-7- (p-chloroanilino) fluorane; 3-dibutylamino- 6-methyl-7- (o-fluoroanilino) fluorane; 3-dibutylamino-6-methyl-7- (m-trifluoromethylanilino) fluorane; 3-dibutylamino-6-methyl-chlorofluorane; 3-dibutylamino-6-ethoxyethyl-7-anilinofluorane; 3-dibutylamino-6-chloro- 7-anilinofluorane; 3-dibutylamino-6-methyl-7-p-methylanilinofluorane; 3-dibutylamino-7- (o-chloroanilino) fluorane; 3-dibutylamino-7- (o- 3-di-n-pentylamino-6-methyl-7-anilinofluorane; 3-di-n-pentylamino-6-methyl-7- (p-chloroanilino) fluorane; Di-n-pentylamino-7- (m-trifluoromethylanilino) fluorane; 3-di-n-pentylamino-6-chloro-7-anilinofluorane; 3-di-n-pentylamino-7 -(P-chloroanilino) fluorane; 3-pyrrolidino-6-methyl-7-anilinofluorane; 3-piperidino-6-methyl-7-anilinofluorane 3- (N-methyl-N-propylamino) -6-methyl-7-anilinofluorane; 3- (N-methyl-N-cyclohexylamino) -6-methyl-7-anilinofluorane; -(N-ethyl-N-cyclohexylamino) -6-methyl-7-anilinofluorane; 3- (N-ethyl-N-xylamino) -6-methyl-7- (p-chloroanilino) fluorane; (N-ethyl-p-toludino) -6-methyl-7-anilinofluorane; 3- (N-ethyl-N-isoamylamino) -6-methyl-7-anilinofluorane; 3- (N- Ethyl (N-isoamylamino) -6-chloro-7-anilinofluorane; 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluorane; Til-N-isobutylamino) -6-methyl-7-anilinofluorane; 3- (N-ethyl-N-ethoxypropylamino) -6-methyl-7-anilinofluorane; 3-cyclohexylamino-6 -Chlorofluorane; 2- (4-oxahexyl) -3-dimethylamino-6-methyl-7-anilinofluorane; 2- (4-oxahexyl) -3-diethylamino-6-methyl-7-ani Linofluorane; 2- (4-oxahexyl) -3-dipropylamino-6-methyl-7-anilinofluorane; 2-methyl-6-p- (p-dimethylaminophenyl) aminoanilinofluorane 2-methoxy-6-p- (p-dimethylaminophenyl) aminoanilinofluorane; 2-chloro-3-methyl-6-p- (p-phenylaminophenyl); 2-chloro-6-p- (p-dimethylaminophenyl) aminoanilinofluorane; 2-nitro-6-p- (p-diethylaminophenyl) aminoanilinofluorane; -Amino-6-p- (p-diethylaminophenyl) aminoanilinofluorane; 2-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluorane; 2-phenyl-6-methyl-6-p -(P-phenylaminophenyl) aminoanilinofluorane; 2-benzyl-6-p- (p-phenylaminophenyl) aminoanilinofluorane; 2-hydroxy-6-p- (p-phenylaminophenyl) Aminoanilinofluorane; 3-methyl-6-p- (p-dimethylaminophenyl) aminoanilinov Oran; 3-diethylamino-6-p- (p-diethylaminophenyl) aminoanilinofluorane; 3-diethylamino-6-p- (p-dibutylaminophenyl) aminoanilinofluorane; 2,4-dimethyl-6 -[(4-Dimethylamino) anilino] -fluorane

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

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

  A conventionally well-known sensitizer can be used as a sensitizer used by this invention. Examples of such sensitizers include fatty acid amides such as stearamide and palmitic acid amide, ethylene bisamide, montanic acid wax, polyethylene wax, 1,2-di- (3-methylphenoxy) ethane, p-benzylbiphenyl, β- Benzyloxynaphthalene, 4-biphenyl-p-tolyl ether, m-terphenyl, 1,2-diphenoxyethane, dibenzyl oxalate, di (p-chlorobenzyl) oxalate, di (p-methylbenzyl) oxalate, Dibenzyl terephthalate, benzyl p-benzyloxybenzoate, di-p-tolyl carbonate, phenyl-α-naphthyl carbonate, 1,4-diethoxynaphthalene, 1-hydroxy-2-naphthoic acid phenyl ester, o-xylene-bis -(Phenyl ether), 4- (m-methyl) Ruphenoxymethyl) biphenyl, 4,4′-ethylenedioxy-bis-benzoic acid dibenzyl ester, dibenzoyloxymethane, 1,2-di (3-methylphenoxy) ethylene, bis [2- (4-methoxy- Examples thereof include, but are not limited to, phenoxy) ethyl] ether, methyl p-nitrobenzoate and phenyl p-toluenesulfonate. These sensitizers may be used alone or in combination of two or more.

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

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

The kind and amount of the dye, developer, and other various components used in the heat-sensitive color forming layer of the present invention are determined according to the required performance and recording suitability, and are not particularly limited. Developer (total) 0.5 to 10 parts by weight, sensitizer 0.5 to 10 parts by weight, stabilizer 0.01 to 10 parts by weight, other components 0.01 to 10 parts by weight Part is used.
Among the developers, the ratio of the first developer to the second developer is preferably 50% by weight or more, more preferably 80% by weight or more, all of which are the first developer and the second developer. Most preferred is a developer. The sulfonamide compound as the first developer is preferably 0.01 to 10.0 parts by weight, more preferably 0.1 to 5.0 parts by weight per 1 part by weight of the diphenylsulfone derivative as the second developer. Use in parts by weight.

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

In the thermosensitive recording material of the present invention, a protective layer can be further provided on the thermosensitive coloring layer.
The protective layer is often mainly composed of a pigment and a resin. For example, a water-soluble polymer such as polyvinyl alcohol or starch is used as the main component.
In the present invention, it is desirable that the protective layer contains a carboxyl group-containing resin, particularly a carboxy-modified polyvinyl alcohol and an epichlorohydrin-based resin and a modified polyamine / amide-based resin from the viewpoints of heat resistance, water resistance, and heat and humidity resistance.

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

The carboxy-modified polyvinyl alcohol used in the present invention is a product in which a carboxyl group is introduced for the purpose of enhancing the reactivity to a water-soluble polymer, such as polyvinyl alcohol and fumaric acid, phthalic anhydride, melittic anhydride, itaconic anhydride, etc. A reaction product of a polycarboxylic acid, or an esterified product of these reaction products, and an ethylenically unsaturated dicarboxylic acid such as vinyl acetate and maleic acid, fumaric acid, itaconic acid, crotonic acid, acrylic acid or methacrylic acid As a saponified product of Specific examples include the production methods exemplified in JP-A-53-91995.
The degree of polymerization and the degree of saponification of the carboxy-modified polyvinyl alcohol used in the present invention can be appropriately selected and used from the viewpoint of the water retention of the paint and the surface strength of the coating layer.

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

  In the present invention, the modified polyamine / amide resin is a polyamide urea resin, polyethylene imine resin, polyalkylene polyamine resin, polyalkylene polyamide resin, polyamine polyurea resin, modified polyamine resin, modified polyamide resin, polyalkylene polyamine urea formalin. Resin, polyalkylene polyamine polyamide polyurea resin, and the like are listed. Specific examples include Sumire Resin 302 (manufactured by Sumitomo Chemical Co., Ltd .: polyamine polyurea resin) and Sumire Resin 712 (manufactured by Sumitomo Chemical Co., Ltd .: polyamine polyurea resin). ), Sumire Resin 703 (manufactured by Sumitomo Chemical: polyamine polyurea resin), Sumire Resin 636 (manufactured by Sumitomo Chemical: polyamine polyurea resin), Sumire Resin SPI-100 (manufactured by Sumitomo Chemical: modified polyamine) Tree ), Sumire Resin SPI-102A (Sumitomo Chemical Co .: modified polyamine resin), Sumire Resin SPI-106N (Sumitomo Chemical Co .: modified polyamide resin), Sumire Resin SPI-203 (50) (Sumitomo Chemical Co., Ltd.) : Polyamide resin), Sumirez resin SPI-198 (manufactured by Sumitomo Chemical Co., Ltd .: polyamide resin), printable A-700 (manufactured by Asahi Kasei), printable A-600 (manufactured by Asahi Kasei), PA6500 (manufactured by Seiko PMC): Polyalkylene polyamine urea formalin resin), PA6504 (manufactured by Starlight PMC: polyalkylene polyamine urea formalin resin), PA6664, PA6638, PA6640, PA6664, PA6664, PA6654, PA6702, PA6704 (above, manufactured by Starlight PMC: polyalkylenepolyamide) Polyamide polyurea resin), CP8994 (manufactured by Seiko PMC: polyethyleneimine resin), and the like. Although not particularly limited, polyamine resins (polyalkylene polyamine resins, polyamine polyurea resins) are considered in terms of color development sensitivity. It is desirable to use a modified polyamine resin, polyalkylene polyamine urea formalin resin, polyalkylene polyamine polyamide polyurea resin).

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

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

The following examples illustrate the invention but are not intended to limit the invention.
The coating liquid used for each coating layer of the heat-sensitive recording material was prepared as follows.
In the description, parts and% indicate parts by weight and% by weight, respectively.

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

Thermosensitive coloring layer coating solution The following solutions A to D were separately wet-ground with a sand grinder until the average particle size became 0.5 μm.
Liquid A (first developer dispersion)
N-phenyl-4-hydroxybenzenesulfonamide (manufactured by Sanko Co., Ltd., trade name: FS001 ^* ) 6.0 parts-polyvinyl alcohol 10% aqueous solution 5.0 parts-water 1.5 parts
^* FS001 is represented by the following formula (Formula 5).

Liquid B (second developer dispersion)
1- [4- (4-Hydroxyphenylsulfonyl) phenoxy] -4- [4- (4-isopropoxyphenylsulfonyl) phenoxy] butane (synthesized by the method described in JP2003-212841. )) 6.0 parts-polyvinyl alcohol 10% aqueous solution 5.0 parts-water 1.5 parts

Liquid C (basic colorless dye dispersion)
-3-dibutylamino-6-methyl-7-anilinofluorane (manufactured by Yamamoto Kasei Co., Ltd., trade name: ODB-2) 6.0 parts-polyvinyl alcohol 10% aqueous solution 5.0 parts-water 1.5 parts D Liquid (sensitizer dispersion)
-1,2-bis (phenoxymethyl) benzene (manufactured by Nikka Chemical Co., Ltd., trade name: PMB-2)
6.0 parts-polyvinyl alcohol 10% aqueous solution 5.0 parts-water 1.5 parts

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

Protective layer coating liquid- Aluminum hydroxide 50% dispersion (trade name: Martinfin OL, manufactured by Martinsberg) 9.0 parts-Carboxyl-modified polyvinyl alcohol (trade name: KL318 <polymerization degree: about 1700) , Saponification degree: 95 to 99 mol%>) 10% aqueous solution 30.0 parts-Polyamide epichlorohydrin resin (trade name: WS4030, manufactured by Seiko PMC Co., Ltd., solid content 25% <degree of cationization: 2.7, molecular weight: 2.2 million, quaternary amine>) 4.0 parts-Modified polyamine resin (trade name: Sumirez Resin SPI-102A, solid content 45%) 2.2 parts-Zinc stearate (manufactured by Chukyo Yushi Co., Ltd.) (Product name: Hydrin Z-7-30, solid content 30%)
2.0 parts A mixture of the above composition was mixed and stirred to prepare a protective layer coating solution.

[Example 1]
Apply and dry the under layer coating solution on one side of high-quality paper (47 g / m ² base paper) with a Meyer bar to 10.0 g / m ² (fan dryer, 60 ° C., 2 minutes) Coated paper was obtained. The thermosensitive coloring layer coating solution was applied and dried (fan drying at 60 ° C. for 2 minutes) so that the coating amount was 6.0 g / m ² on the under layer of the under-coated paper. This sheet was processed with a super calendar so as to have a smoothness of 500 to 1000 seconds to obtain a heat-sensitive recording material.

[Example 2]
Thermosensitive recording was carried out in the same manner as in Example 1 except that the developer of the liquid A in the thermosensitive coloring layer coating solution was changed to bis (N-phenyl-N ′-(4-methylsulfonyl) urea) methane (the following formula). The body was made.

[Example 3]
A thermosensitive recording material was prepared with 7.5 parts of silica in the thermosensitive coloring layer coating solution of Example 1, and the protective layer coating solution was applied and dried so that the coating amount was 3 g / m ^2. (Blow dryer, 60 ° C., 2 minutes) to produce a heat-sensitive recording material.

[Comparative Example 1]
A heat-sensitive recording material was prepared in the same manner as in Example 1 except that the liquid B in the heat-sensitive coloring layer coating liquid was changed to 36 parts and the liquid A was not mixed.
[Comparative Example 2]
A thermosensitive recording medium was produced in the same manner as in Example 1 except that the A liquid in the thermosensitive coloring layer coating liquid was changed to 36 parts and the B liquid was not mixed.
[Comparative Example 3]
A heat-sensitive recording material was produced in the same manner as in Example 1 except that the developer of the liquid B in the heat-sensitive color developing layer coating solution was changed to a diphenylsulfone cross-linking compound (Nippon Soda Co., Ltd., trade name: D-90). .
[Comparative Example 4]
A heat-sensitive recording material was produced in the same manner as in Example 3 except that the liquid A in the heat-sensitive coloring layer coating liquid was changed to 36 parts and the liquid B was not mixed.

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

<Plasticizer resistance: Barcode readability>
After contacting the front and back of the thermal recording material printed with barcode (CODE39) with Zebra label printer 140XiIII, dial wrap (made by Mitsui Chemicals) was left in an environment of 40 ° C and 90% for 24 hours. (Equipment made by Nippon Systex, Quick Check PC600). Evaluation is performed by ANSI grade (CEN method, number of measurements 10 times), and evaluation is as follows. If the rating is C or higher, the bar code reading aptitude is at a level that is not practically problematic. On the other hand, if the rating is equal to or lower than D, the bar code reading aptitude is practically problematic.
(Excellent) A>B>C>D> F (Inferior)
<Heat resistance>
A blank paper sample was allowed to stand in an 80 ° C. environment for 24 hours, and the color density before and after the test was measured to obtain the ground color development value.
Ground color development value = color density after test−density before test A: ground color development value less than 0.1 ○: ground color development value is 0.1 or more and less than 0.3 Δ: ground color development value is 0. 3 or more and less than 0.5 ×: Ground color development value is 0.5 or more

表１から、感熱発色層に第一顕色剤として本願発明のスルホンアミド化合物、及び第二顕色剤として本願発明のジフェニルスルホン誘導体を含有させた場合には、その感熱記録体が耐可塑剤性に優れていることがわかる。 The evaluation results are shown in the table below.

From Table 1, when the heat-sensitive color developing layer contains the sulfonamide compound of the present invention as the first developer and the diphenylsulfone derivative of the present invention as the second developer, the heat-sensitive recording material is a plasticizer. It turns out that it is excellent in property.

Claims (4)

A heat-sensitive recording material provided with a heat-sensitive coloring layer containing a colorless or light-colored electron-donating leuco dye and an electron-accepting developer on a support, the heat-sensitive coloring layer having a first electron-accepting color development The following general formula (chemical formula 1)
(R ¹ —SO ₂ NH— (CONH) _m — (C _a H _2a ) —R ² —) _n —R ³
(Wherein R ¹ represents a substituted or unsubstituted aryl group, m represents 0 or 1, a represents an integer of 0 to 3, R ² represents a substituted or unsubstituted arylene group, and n represents Represents an integer of 1 to 4, and R ³ represents a hydrogen atom, a hydroxyl group or a carboxyl group when n = 1, and a bivalent to tetravalent fat corresponding to n having 1 to 4 carbon atoms when n = 2 to 4. As a second electron-accepting developer, a sulfonamide compound represented by the following general formula:

(In the formula, R ⁴ represents a linear or branched saturated or unsaturated hydrocarbon having 1 to 12 carbon atoms, and R ^{5 to} R ¹⁰ each independently represent a halogen atom or a carbon number of 1 to 1; 12 represents an alkyl group or an alkenyl group, p, q, r, s, t and u each represent an integer of 0 to 4, o represents an integer of 0 to 5, and A independently represents an ether. A linear or branched saturated or unsaturated hydrocarbon group having 1 to 12 carbon atoms, which may have a bond, and a diphenylsulfone derivative represented by formula (1). . The heat-sensitive recording material according to claim 1, wherein o is 0. The heat-sensitive recording material according to claim 1, further comprising a protective layer on the thermosensitive coloring layer, wherein the protective layer contains a carboxyl group-containing resin, an epichlorohydrin-based resin, and a modified polyamine / amide-based resin. The heat-sensitive recording material according to claim 3, wherein the modified polyamine / amide resin is a polyamine resin.