JPH03244585A - Sensitizer and material for thermal recording - Google Patents

Abstract

PURPOSE:To obtain thermal recording material characteristic of high sensitivity, high degree of whiteness, excellent light-fastness, superb moisture and plasticizer resistance by adding a sensitizer shown by a specific formula. CONSTITUTION:The subject material consists of a mixture layer of an electron- donative colorless color former and an electron-receptive developer and a layer of a compound shown by formula (I) as a sensitizer formed on the mixture layer, on a support. Alternatively, the subject material is composed of a mixture layer of a compound (A) expressed by formula (I) and an electron-donative colorless color former and a mixture layer of said compound (A) and said electron-receptive developer laminated on the former mixture layer, on the support. As another material making method, the subject material consists of a mixture layer of the compound expressed by formula (I) and the electron- receptive developing substance and a mixture layer of said compound (A) and said electron-donative colorless color former. In the formula (I), R is a 6C or less hydrocarbon group; Y is a low alkylene group; Z is a -R group (a 6C or less hydrocarbon group), a -OR group, a -CONHR group, a -COR group, an NO2 group, a CN group or a halogen atom; and n is 0 or an integer of 1 or 2.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to a sensitizer and a heat-sensitive recording material.

More specifically, the present invention relates to a heat-sensitive recording material that has extremely high color development sensitivity and excellent whiteness, light resistance, moisture resistance, and plasticizer resistance.

[Prior Art] Heat-sensitive recording materials are produced by melting an electron-donating colorless coloring agent (hereinafter also referred to as coloring agent) and an electron-accepting color developing substance (hereinafter also referred to as coloring agent) with heat to cause them to associate. It is made using the principle of color development.

Thermosensitive recording materials have recently been used for various types of recording such as faxes and POS labels.

Lactone compounds such as crystal violet lactone are used as color formers, and solid acidic substances, phenol compounds, organic acids, or metal compounds thereof are used as color developers.

Furthermore, in recent years there has been a significant demand for faster information, and various high-speed devices have been developed. Along with this, highly sensitive heat-sensitive recording materials have also been developed. For example, as a method for improving sensitivity by using color formers and developers in combination, sensitizers such as benzyl biphenyls are used in combination (Japanese Patent Application Laid-open No. 80-82382), 1,2-bis(phenoxy)ethane Combination use (Japanese Unexamined Patent Publication No. 60-56588) has been reported.

[Problems to be Solved by the Invention] However, heat-sensitive recording materials using conventional sensitizers have insufficient light resistance, moisture resistance, and plasticizer resistance.

[Means for Solving the Problems] The present inventors have conducted intensive studies to obtain a heat-sensitive recording material that has high sensitivity, high whiteness, light resistance, moisture resistance, and plasticizer resistance, and as a result, the present invention has been developed. Reached.

That is, the present invention provides a heat-sensitive recording material which has an electron-donating colorless coloring agent and an electron-accepting color-developing substance on a support and which develops color by heat-melting. Hydrogen group; Y is lower alkylene group; 2 is -R group (R is a hydrocarbon group having 6 or less carbon atoms), -〇R group,
-CONHR group.

-COR group, NO2 group, CN group or halogen atom; n
is an integer of 0.1 or 2]
); and a heat-sensitive recording material which has an electron-donating colorless color former and an electron-accepting color developer on a support and is heat-melted to develop color, as claimed in claim 1.
This is a heat-sensitive recording material characterized by containing the sensitizer described above.

In general formula (1), the hydrocarbon group having 6 or less carbon atoms for R is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, 5ec-butyl, tart
- Straight chain or branched alkyl groups such as butyl, pentyl, hexyl; straight chain or branched alkenyl and alkynyl groups such as vinyl, allyl, propenyl, isopropenyl, 2-butenyl, ethynyl, 2-propynyl; phenyl, cyclopentyl , a carbocyclic group such as a cyclohexyl group.

Preferred are methyl, ethyl, tert-butyl, allyl, and phenyl.

Examples of the lower alkylene group for Y include alkylene groups having 1 to 4 carbon atoms, such as ethylene, propylene, and butylene groups, and preferably methylene and ethylene groups.

In Z, the hydrocarbon group having 6 or less carbon atoms for R can be the same hydrocarbon group as R in the general formula (1) described on this page (the preferred compounds are also the same).

n is Oll or 2, preferably O or 1.

0 is more preferred.

The specific examples of the compound (A) represented by the general formula (1) are as follows.

[Ether compound of 1-cohydroxyphenylalkyl ketones and phenylalkyl halides C13Co-@
-0CH2-@ CH3CO+0C112CH2-4 C2Hs CO-@-OCH 0 C2H5CO+0CH2CHr@
etc. [Ether compounds of 2-hydroxyphenylalkyl ketones and phenylalkyl halides CH3CO
+0CH2+CH3 CH3CO-o-0CH2CH2+CH3C2H5C0
◆0CH2◆CH3 C2H5C0+0CH2CH2-o-CH3CH3Co
4-OCII2-@-@ C2H3CO-@1-OCH2-o-O1 etc. [Ether compound of 3-hydroxyphenyl alkyl ketones and phenyl alkyl halides having 10R group CH3CO+0CH2-o-OCH3 CH3CO* 0CII2CH2*0cH3C2H5CO
-4-OCH2-o-OCH3C2H5CO number 0CH2
CH2*0CI(3CH3CO-e-OCH2-@-0
7C2H3CO-o-OCH2+0-@
etc. [4] Hydroxyphenylalkyl ketones and -
Ether compound with phenylalkyl halide having C○NHR group CH3CO-@-0CH2-@-CONHCH3CH3
CO-e-OCH2C)12+C0NHCJ(3C2H
5CO-@-0CH2-@-CONHCH3CH3CO
-@-0CH2-@-CONH-@ Sudo[Ether compound of 5-hydroxyphenylalkyl ketones and phenylalkyl halides having 100R group CHa Co-@1-OCH2+ COCH3C13C
o-e-OCR2Cl(2-e-COCH3C2H5C
O-@-0CH2-o-COCH3CH3CO*0CH
2*CO CH3Co-@-0CH2CH2-@-CO-@C2H
3CO-e-OCH2-@-CO-■[6-hydroxyphenylalkylketones--Ether compounds with phenylalkyl halides having NO2 groupCH3CO-o-0CH2*N02 etc.C2II5CO-@-0CH2◆N02C2H5CO −
@? -0CH2C■I2◆N02 etc. [7] Ether compound of hydroxyphenyl alkyl ketones and phenyl alkyl halides having a CN group CH3CO+0CH2FC2H3CO-o-OCH2-61-cNC2H5CO
-@-0cH2cH2+cN etc. [8
] Ether compound of hydroxyphenyl alkyl ketones and phenyl alkyl halides having 01 atoms
Among the compounds (A), preferred are:
Ether compounds of hydroxyphenylalkyl ketones and phenylalkyl halides, ether compounds of hydroxyphenylalkyl ketones and phenylalkyl halides having -R groups, hydroxyphenylalkyl ketones and phenyl having 10R groups Ether compounds with alkyl halides, ether compounds of hydroxyphenylalkyl ketones and phenylalkyl halides with a -COR group, ether compounds with hydroxyphenylalkyl ketones and phenylalkyl halides with a -CN group, and hydroxyphenyl Examples include ether compounds of alkyl ketones and phenyl alkyl halides having 01 atoms.

Particularly preferred are ether compounds of hydroxyphenylalkyl ketones and phenylalkyl halides.

Two or more different types of compounds (A) may be used in combination. In addition, the compound (A) described in the specification of Japanese Patent Application No. 1-28329 filed by the present applicant, the compound (A) described in the specification of Japanese Patent Application No. 1-41133, the compound (A) described in the specification of Japanese Patent Application No. 1-134080
Compound (A) described in the specification, Japanese Patent Application No. 1-15130
Compound (A) described in Specification No. 4, Japanese Patent Application No. 1-1587
Compound (A) described in specification No. 29, patent application No. 1-256
Compound (A) described in specification No. 220, patent application No. 1-25
Compound (A) described in specification No. 6221, patent application No. 1-2
Compound (A) described in specification No. 63551, patent application No. 1-
Compound (A) described in Specification No. 286747, Patent Application No. 1999
Of the compound (A) described in -297142, the compound (A) described in Japanese Patent Application No. 1-323199, and the compound (A) described in Japanese Patent Application No. 2-5541, - A species or a combination of two or more species may be used.

The compound (A) so-called sensitizer represented by the general formula (1) can be produced by any method, for example, hydroxyphenylalkyl ketones and a phenylalkyl halide which may have a substituent. A method for obtaining an ether compound by dehydrohalogenation reaction with

The method for obtaining an ether compound by dehydrohalogenation reaction between hydroxyphenylalkyl ketones (such as hydroxyphenyl ketone) and phenylalkyl halides (such as benzyl chloride) which may have a substituent is a known method, such as carbonic acid. potassium, sodium hydroxide,
It can be obtained by reacting hydroxyphenylalkyl ketones and phenylalkyl halides which may have substituents at 50 to 120°C in the presence of an alkali such as sodium methylate.

As the color forming agent constituting the recording layer in the heat-sensitive recording material of the present invention, those used in conventional heat-sensitive or pressure-sensitive recording materials can be used. For example, color formers such as triarylmethane, diphenylmethane, xanthine, phenothiazine, and spiropyran are preferably used.

As a triarylmethane coloring agent, 3,3-bis(
p-dimethylaminophenyl)-6-dimethylaminophthalide (crystal violet lactone, hereinafter abbreviated as CVL), 3,3-bis(p-dimethylaminophenyl)
Phthalide, 3-(p-dimethylaminophenyl)-3-
(1,2-dimethylindol-3-yl)phthalide,
3-(p-dimethylaminophenyl)-3-(2-methylindol-3-yl)phthalide, 3-(p-dimethylaminophenyl)-3-(2-phenylindole-
3-yl)phthalide, 3,3-bis(1,2-dimethylindol-3-yl)-5-dimethylaminophthalide, 3,3-bis-(l,2-dimethylindole-3-
yl)-6-dimethylaminophthalide, 3,3-bis(
9-Ethylcarbazol-3-yl)-5-dimethylacunophthalide, 3,3-bis(2-phenylindol-3-yl)-5-dimethylaminophthalide, 3-p-
Dimethylacunophenyl-3-(l-methylpyrrole-
2-yl)-6-dimethylaminophthalide and the like.

Examples of diphenylmethane-based coloring agents include 4,4'-bis-dimethyla-based novelbenzhydrin benzyl ether, N-
Examples include halophenyl leuco auramine, N-2.4.5-trichlorophenyl leuco auramine, and the like.

As the xanthine coloring agent, rhodamine B-anilinolactam, rhodamine B (p-nitroanilino)lactam, rhodamine B (p-chloroanilino)lactam, 3
-dimethylamino-6-medoxyfluorane, 3-diethylamino-7-methoxyfluorane, 3-diethylamino-twochloro-6-methylfluorane, 3-diethylamino-7-(acetylmethylamino)fluorane,
3-diethylamino-7-(dibenzylamino)fluoran, 3-diethylamino-7-(methylbenzylamino)fluoran, 3-diethylamino-7-(chloroethylmethylamino)fluorane, 3-diethylamino-
Examples include 7-(diethylamino)fluoran.

Examples of the phenothiazine color former include benzoyl leucomethylene blue and p-nitrobenzoyl leucomethylene blue.

As a spiropyran coloring agent, 3-methyl-spiro-
dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3,3'-cyclospirodinaphthopyran, 3-
Examples include benzyl-spiro-dinaphthopyran, 3-methyl-naphtho-(3-methoxy-benzo)-spiropyran, and 3-propyl-spiro dibenzodipyran.

These color formers may be used alone or in combination of two or more.

On the other hand, as the color developer, various electron-accepting substances that react with the color former when heated to develop color can be used. As such an electron-accepting substance, a phenolic substance, an organic or inorganic acidic substance, or a salt thereof can be used. Examples of known color developers include "Color Developers for Thermal Recording Paper (1) to (Complete)" in "Paper Pulp Technology Times", "Tic Time Co., Ltd., Vol. 30, No. 6 to Vol. 31, No. 3".
, written by Takashi Shiga" and "Color developers for thermal recording paper (1) to (complete), written by Takashi Shiga" in "Vol. 32, No. 4 to Vol. 32, No. 10", both of which can be used. Specifically, the following can be mentioned.

(1) Bisphenol color developer (1-1) Non-sulfur-containing bisphenol color developer 2- (
4-hydroxyphenyl)propane, 2-(3'-hydroxyphenyl)propane, tetrabromobisphenol A, 4,4'-isopropylidenediphenol, 4
, 4'-butylidene bis(2-t-butyl-5-methylphenol) and other bisphenol A derivative compounds, 4,
4'-methylenebis(2-cyclohexyl-5-methylphenol), 4,4'-isopropylidenebis(2
-cyclohexyl-5-methylphenol), 4.4'
-butylidene bis(2-cyclohexyl-5-methylphenol), 4,4'-cyclohexylidene bis(2-cyclohexyl-5-methylphenol)
-Cyclohexyl-5-methylphenol L3,3-bis(3-cyclohexyl-4-hydroxy-5-methylphenol)ethyl butanoate, 4-[1,1-bis(
4-hydroxyphenyl)ethyl]biphenyl, 2-
[1,1-bis(4-hydroxyphenyl)ethyl]naphthalene, ■-phenyl-1,1-bis(4-hydroxyphenyl)butane, 1,1-bis(p-hydroxyphenyl)cyclohexane, 4,4'- Butylidene bis(
Bisphenol A related compounds such as 2-cyclohexyl-5-methylphenol), methyl-phenyl-methylidene bisphenol, 1,1-bis(4-hydroxyphenyl)acetic acid, 2,2-bis(4-hydroxyphenyl) ) propionic acid, bis(4-hydroxyphenyl)acetic acid methyl ester, bis(4-hydroxyphenyl)#acid-n-butyl, bis(4-hydroxyphenyl)acid propargyl, bis(4-hydroxyphenyl)#acid cinnamyl, benzyl bis(4-hydroxyphenyl)acetate,
Bis(4-hydroxyphenyl)phenyl acetate, bis(
Phenethyl #4-hydroxyphenyl), bis(4-
hydroxyphenyl)acetate-β-(4'-ethoxyphenoxy)ethyl, 2,2-bis(4-hydroxyphenyl)#acid-3-phenoxypropyl, 2,2-bis(4'-ethoxyphenoxy)ethyl
-hydroxyphenyl)valerate-β-(4'-methylphenoxy)ethyl, bis(4-hydroxyphenyl)stearamide, 1,3-bis(4-hydroxyphenyl)propane, 2,4-bis(4- hydroxyphenyl)-4-methylpentane, 1,3-di[2-(4-hydroxyphenyl)-2-propyl]benzene, 1,3
-di[2-(3,5-dimethyl-4-hydroxyphenyl)-2-propyltobenzene, bisphenol 1,
Bis(hydroxyphenyl) acid compounds such as 1-bis(hydroxyphenyl)-1-phenylethane (1-2) Sulfur-containing bisphenol color developer 4.4' dihydroxyphenyl diphenyl sulfone, 2.4' dihydroxy Phenyl diphenyl sulfone, bis-(3-allyl-4-hydroxyphenyl) sulfone, bis-(3
-allyl-4-hydroxyphenyl)sulfone, 3-3
Bisphenol sulfone derivatives such as '-sulfonylbis(4-hydroxybenzoic acid methyl ester) and 1,3-bis(p-hydroxyanilinosulfonyl)benzene;
Monoethers of bisphenolsulfones such as 4-hydroxy-4'-benzyloxydiphenylsulfone and 4-hydroxy-4'-isopropoxydiphenylsulfone;
Bis(3,5-dimethyl-4-hydroxyphenyl) sulfide, bis(2-methyl-5-isopropyl-4-
hydroxyphenyl) sulfide, 4,4'-thiobis(6-ter-butyl-3-methylphenol), 1.
5-di(4-hydroxyphenylthio)-3-oxypentane, 1,8-di(4-hydroxythio)-3,6-
Thioxaoctane, 1,3-di(4-hydroxyphenylthio)acetone, 1,7-di(4-hydroxyphenylthio)-3,5-dione, 1,2-di(4-hydroxyphenylthio)phenyl Ethane, 1,2-di(4-hydroxyphenylthio)-1-(4-chlorophenyl)ethane, methyl 4-hydroxyphenylthio-4-hydroxyphenyl)acetate, methyl bis(4-hydroxyphenylthio)w acid, 4-benzyloxyphenyl-4
- Bisphenol sulfide such as hydroxyphenyl sulfide; (2) Hydroxyarylcarboxylic acid color developer (2-1
) Hydroxybenzoic acid color developer P-hydroxybenzoic acid, m-hydroxybenzoic acid, salicylic acid, methyl p-hydroxybenzoate, benzyl p-hydroxybenzoate,
p-hydroxybenzoic acid-β-p-methoxyphenoxyethyl, P-hydroxybenzoic acid-β-phenoxyethyl, p-hydroxybenzoic acid-β-p-methoxyphenoxyethyl, P-hydroxybenzoic acid-2-(o- Hydroxybenzoic acid and P-hydroxybenzoic acid esters such as hydroxyphenylthio)ethyl; 2,4-dihydroxybenzoic acid octadecyl, 2,4-dihydroxybenzoic acid ~ β-p-ethoxyphenoxyethyl, 2,4-
β-methallyloxyethyl dihydroxybenzoate, 2
, 4-dihydroxybenzoic acid-β-ethyloxyethyl, 2,4-dihydroxy-β-phenylthioethyl, 1
, 4-cyclohexanedimethanol-bis-(P-hydroxybenzoic acid) ester, 1,4-ethylene glycol-bis-(P-hydroxybenzoic acid) ester, and other hydroxybenzoic acid derivatives (2-2) Salicylic acid-based color developer Salicylic acid metal salts (Zn, Mg, Ca, Al), 4-tetradecyloxysalicylic acid, 4-β-P-)lyoxyethoxysalicylic acid, 3,5-di(α-methylbenzyl)salicylic acid, 3,5- Di(α,α-dimethylbenzyl)salicylic acid, 3,5-di-ter-butylsalicylic acid, 3-isopropenyl-5-ter-butylsalicylic acid, 3-vinyl-5-cyclohexanoic acid, 3-vinyl-
5-Benzylsalicylic acid, 5-myristoylsalicylic acid, 5-phenylacetylsalicylic acid, methylphenoxyacetylsalicylic acid, 4-primary stoylsalicylic acid, 4-phenylacetylaminosalicylic acid, 2゜2-
Bis(3-carboxy-4-hydroxyphenyl)propane, 1,4-bis(3-carboxy-4-hydroxycumyl)benzene, bis(2-hydroxy-3-carboxy-5-α-phenethylphenyl)methane, etc. Salicylic acid derivative (2-3) Other hydroxyarylcarboxylic acid color developers dimethyl 4-hydroxyphthalate, oxidized lead salt of mono-2-hydroxyethyl 3,4,5.6-tetrachlorophthalate, 3, Phthalic acid derivatives such as zinc salt of mono-3-hydroxy-2,2-dimethylpropyl 4,5,6-tetrachlorophthalate, p-chlorobenzyl gallate, benzyl gallate, p-vinylbenzyl gallate Gallic acid derivatives such as; 1-hydroxy-4-benzyloxy-
Naphthoic acids such as 2-naphthoic acid, 1-acyloxy-4-benzyloxy-2-naphthoic acid, 2-acyloxy-4-benzyloxy-1-naphthoic acid, and polyvalent metal salts of these acids such as Zn and Mg. Derivatives; (2-4) Other carboxylic acid color developers 0-methyl fumarate, P-methyl fumarate, 0-ethyl fumarate,
P-benzyl fumarate, 0-naphthylmethyl fumarate,
Zinc indole-2-carboxylate, calcium indole-2-carboxylate, zinc 1-methylindole-2-carboxylate, zinc p-nitrobenzoate, P-nitrobenzoic acid moiety, L-ascorbic acid, etc. (3) Sulfone Color developer methyl 4-hydroxybenzenesulfonate, ethyl 4-hydroxy-3-methyl-5-bromobenzenesulfonate, ethyl 4-hydroxy-3,5-dibromobenzenesulfonate, 4-hydroxy-42-methyldiphenyl Sulfone, 3', 4') dimethylene-4-hydroxydiphenylsulfone, 2-(4-hydroxybenzenesulfonyl)naphthalene, 1-(4-hydroxybenzenesulfonyl)naphthalene, 3-allyl-4-hydroxy-4'-methyl diphenylsulfone, 3-allyl-
4-hydroxy-42-methoxydiphenyl sulfone,
3-allyl-4-hydroxy-4'-(2-phenoxyethoxy)diphenylsulfone, 3,4-dihydroxyphenyl-P-tolylsulfone, 2,2'-bis(4-
hydroxybenzenesulfonyl)ethyl ether, 4-
Hydroxy-42-isopropoxydiphenylsulfone, 4-hydroxy-4'-chlorodiphenylsulfone,
Sulfonic color developers such as 3,5-di-β-phenoxyethoxycarbonylbenzenesulfonic acid, 2-β-naphthoxyethoxynaphthalene-6-sulfonic acid; N-benzenesulfonyl-m-aminophenol, N-(α -naphthalenesulfonyl)-m-aminophenol, 1,3-bis(P-hydroxyanilinosulfonylbenzene, N-
, (2-phenoxyethyl)-4-hydroxybenzenesulfonamide, N-(3-phenoxypropyl)-4
-Hydroxybenzenesulfonamide, N-(phenylsulfonyl)-p-)luenesulfonado, n-butyl-N-(o-carboxyphenylsulfonyl)-P-
Aminobenzoate, N-(dimethylsulfamoyl)
-p-) Sulfonamide compounds such as luenesulfonamide and N,N'-diphenylsulfonamide; Sulfonyl chloride compounds such as α-naphthalenesulfonyl chloride and p-phenylbenzenesulfonyl chloride These color developers may be used alone or in combination. More than one species may be mixed and used.

In the heat-sensitive recording material of the present invention, the amount of compound (A) represented by general formula (1) used is usually 1 to 200 parts by weight, preferably 3 to 100 parts by weight, based on 100 parts by weight of the color developer. Particularly preferably, the amount is in the range of 10 to 70 parts by weight. If the amount of compound (A) used is less than 1 part by weight, the effect of improving sensitivity in thermal recording is poor, and if it exceeds 200 parts by weight, the effect of improving sensitivity is already saturated and is uneconomical.

The ratio of the color former to the color developer is usually 5 to 100 parts by weight, preferably 10 parts by weight per 100 parts by weight of the color former.
~70 parts by weight, particularly preferably 20-50 parts by weight. When the amount of the color developer used is less than 5 parts by weight, the desired color density cannot be obtained, and when it exceeds 100 parts by weight, the color density reaches an equilibrium and it is no longer economical to use any more.

Next, a method for producing the heat-sensitive recording material of the present invention will be described.

Compound (A), a color former, and a color developer are separately dispersed to produce a suspension solution. Next, mix each suspension solution,
The mixture (coating liquid) is coated on a support to produce a heat-sensitive recording material.

In detail, the compound (A) and the binder, the color former and the binder, and the color developer and the binder are each mixed in water with a surfactant (2-ethylhexylsulfosuccinate soda salt, naphthalenesulfonic acid), if necessary. 10 μ or less, preferably 3
Pulverize and disperse into particles smaller than μ to make a coating liquid.

Examples of the binder include polyvinyl alcohol, starch and its derivatives, cellulose derivatives such as methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, and ethylcellulose; sodium polyacrylate, polyvinylpyrrolidone, acrylic amide/acrylic ester copolymer, Acrylic acid amide/acrylic ester/methacrylic acid terpolymer, styrene/maleic anhydride copolymer alkali salt, isobutylene/maleic anhydride copolymer alkali salt,
In addition to water-soluble polymers such as polyacrylamide, sodium alginate, gelatin, and casein, polyvinyl acetate, polyurethane, styrene/butadiene copolymer, polyacrylic acid, polyacrylic acid ester, and vinyl chloride/vinyl acetate copolymer.

Latex such as polybutyl methacrylate, ethylene/vinyl acetate copolymer, styrene/butadiene/acrylic copolymer can be used.

The coating solution is prepared by combining suspension solutions of each compound as shown in Table 1 below.

Table 1 The symbol ◯ in Table 1 means that, for example, coating liquid (b) is a mixture of a suspension of compound (A) and a suspension of a coloring agent.

Further, each coating liquid may contain, if necessary, auxiliary additive components commonly used in this type of heat-sensitive recording material, such as fillers, thermofusible substances, lubricants, and the like. Examples of fillers include calcium carbonate, silica, zinc oxide,
In addition to inorganic fine powders such as titanium oxide, alkium hydroxide, zinc hydroxide, barium sulfate, clay, kaolin, talc, and surface-treated calcium carbonate and silica, urea/
Examples include organic fine powders such as formalin resin, styrene/methacrylic acid copolymer, and polystyrene resin. Examples of thermofusible substances and lubricants include higher fatty acids or their esters, amides, or metal salts, as well as various waxes, condensates of aromatic carboxylic acids and amines, benzoic acid phenyl esters, higher linear glycols, Examples include dialkyl 3,4-epoxy-hexahydrophthalate, higher ketones, and other thermofusible substances having a melting point of about 50 to 200°C.

Examples of the support include paper, synthetic paper, and synthetic resin film, with paper being preferred.

As a coating method, the following methods (I) to (■) can be used. That is, the coating liquids (a) to (g) are applied to the support.
) can be applied using an air knife coater, blend coater, roll coater, wipe press or the like to form a heat-sensitive recording layer.

(I) Coating the coating liquid (a) onto the support. FIG. 1 shows the heat-sensitive recording material obtained. In FIG. 1, 1 is a support, and 2 is a layer containing a mixture of compound (A), a color former, and a color developer.

(n) Coating the coating liquid (d) on the support, and further coating the coating liquid (e) on top of the coating liquid (d). FIG. 2 shows the heat-sensitive recording material obtained. In FIG. 2, 5 is a layer containing a mixture of a color former and a color developer, and 6 is a layer of compound (A).

(m) Coating the coating liquid (e) on the support, and further coating the coating liquid (d) on top of the coating liquid (e). FIG. 3 shows the heat-sensitive recording material obtained. In FIG. 3, 6 is a layer of compound (A), and 5 is a layer containing a mixture of a color former and a color developer.

(IV) Coating solution (g), coating solution (e), and coating solution (f) are coated on the support in a layered manner. FIG. 4 shows the heat-sensitive recording material obtained. In FIG. 4, 8 is a color developer layer, 6 is a compound (A) layer, and 7 is a color former layer.

(V) Coating liquid (f), coating liquid (e), and coating liquid (g) are sequentially layered on the support. The obtained thermosensitive recording material is shown in FIG. In FIG. 5, 6 is a layer of compound (A), 7 is a layer of color former, and 8 is a layer of color developer.

(Vl) Coating liquid (b) is coated on the support, and coating liquid (c) is further coated on top of the coating liquid (b). The obtained thermosensitive recording material is shown in FIG. In Figure 6, 3 is compound (A)
4 is a layer containing a mixture of compound (A) and a color developer, and 4 is a layer containing a mixture of compound (A) and a color developer.

(■) Coating liquid (c) is applied onto the support, and coating liquid (b) is further applied on top of the coating liquid (c). The obtained thermosensitive recording material is shown in FIG. In FIG. 7, 4 is a layer containing a mixture of compound (A) and a color developer, and 3 is a layer containing a mixture of compound (A) and a color former.

Preferred coating methods and heat-sensitive recording materials are (II) (V
I) and (■).

The coating thickness of each layer is determined depending on the form of the heat-sensitive recording material and other conditions. The coating amount is not particularly limited, but the dry weight is usually 0.5 to 20 g/m, preferably 1 to 15 g/m, particularly preferably 3 to 10 g/m.
It is.

[Examples] The present invention will be further described below with reference to Examples, but the present invention is not limited thereto. Parts and percentages in the examples are by weight. Further, the test methods in the examples are shown below.

(Test Methods) (1) Color Development 1) Dynamic Color Development Test The produced thermal recording paper was tested for the relationship between operating time (pulse width) and color density using an MSI type thermal head printing device. Reflection density was measured using a Macbeth densitometer (manufactured by Macbeth) at 0.1 to 1.0 m5ec and a voltage of 22v0. The larger the value, the higher the color density.

2) Static color development test The prepared thermal recording paper was colored using a thermal gradient heat sealer under the conditions of a temperature range of 70'C to 100"C, a printing pressure of 2 kHz/cm, and a pressure bonding time of 2 seconds, and the color density was measured. Densitometer 1)
Same as .

(2) Whiteness (background fog) Hunter white charcoal before coloring thermal recording paper, B value Mu
lti 5pectro Co1our Meter
Measurement was performed using MSC-2 type. A large value indicates a high degree of radial chromaticity.

(4) [Ef The image area colored in the photochromic test was irradiated at 80° C. for 72 hours using a fade meter, and the color density of the irradiated area was measured.

The concentration meter is the same as 1).

(5) Humidity Resistance Test The image area colored in the color development test was left in a constant temperature and humidity chamber at 45° C. and 90% RH for 24 hours, and then the color density of the image area was measured. The concentration meter is the same as 1).

(4) Plasticizer Resistance Test A plastic eraser was placed on the image area that had been colored in the color development test, and after being left for 24 hours, the color density of the image area was measured. The concentration meter is the same as 1).

Examples 1 to 3, Comparative Examples 1 and 2 After each of the following liquids A, B, or C was ground and dispersed in a ball mill for 24 hours, the liquids were sufficiently mixed to prepare coating liquids I to H. This coating liquid was applied to high-quality paper (basis weight 5Qg/m
) was coated with a doctor blade to a dry solid content of 6 g/m, and after drying, it was coated onto thermal recording paper (Examples 1 to 3).
)It was created.

As Comparative Examples 1 and 2, comparative sensitizer suspension solutions H-1 and H-2 were used instead of the sensitizer suspension solution of the present invention in Solution A.
(Comparative Examples 1 and 2) was prepared in the same manner using (a conventional suspension solution of a compound).

Table-2 [Liquid A: Sensitizer suspension solution (parts) Compound (1); @-CH20+COCH3 Compound (2); @)-CH20+C0C2H5 Compound (3); CH3 CH2O*COCH3 Compound (4) ( Conventional product); e-CH2BetoO Compound (5) (Conventional product); [turbid solution] 3-(N-ethyl N-pentylamino-6-methyl-7
- Anilinofluorane [S-205 manufactured by Yamada Chemical Co., Ltd. 10 parts Hydroxyethyl cellulose 41 (5% aqueous solution) [Liquid C: suspension solution of color developer] Bisphenol A Calcium carbonate polyvinyl alcohol (5% aqueous solution) 30 Parts 10 parts 40 parts Water table - 3 [Coating liquid] 20 parts (parts) Water 50 parts [Recording paper performance table - 4 Dynamic coloring test table - 6 Table 5 Static coloring test table - From 4 to 6 As is clear, the color development of the thermal recording paper of the present invention was superior to that of the conventional thermal recording paper (Comparative Examples 1.2). The light resistance, moisture resistance, and plasticizer resistance of the thermal recording paper of the present invention were superior to those of conventional thermal recording paper (Comparative Examples 1.2).

Examples 4 to 6, Comparative Example 3 The following solutions D and E were ground in a ball mill for 24 hours.
After being dispersed, a coating solution was prepared. Apply this coating liquid to high-quality paper (basis weight 6
0g/m2) to methods (I), (Vl) and (■),
That is, for (I), a mixture of liquids D and E (1/1 weight ratio) was applied to paper using a doctor blade so that the dry solid content was 8 g/m'', and then dried. The coating liquid was applied with a doctor blade to a dry solid content of 4 g/m2, and then coating liquid E was applied on this layer in the same manner and dried. (■) is (VI ), liquid E was applied first, and then liquid D was applied.The amount of coating was the same as in (VI).

[Liquid D: Mixed suspension solution of sensitizer and color former CH30+C
H2O+COCH3 10 parts 3-diethylamino-6-methyl 7-anilinofluorane 30 parts Calcium carbonate 5 parts Polyvinyl alcohol (5% aqueous solution) 35 parts Water
40 parts [Liquid E: mixed suspension of sensitizer and color developer] CH30-@-CH2O-o-COCH35
Part Bisphenol A 20 parts 1
．． 5-di(4-hydroxyphenylthio)-3-oxapentane 5 parts calcium carbonate
5 parts polyvinyl alcohol (5 parts
% aqueous solution) 35 parts water
25 parts Coating method (I), (Vl) and (■
The thermosensitive recording papers prepared in ) were designated as Examples 4.5 and 6, respectively.

Further, as Comparative Example 3, a thermosensitive recording paper (Comparative Example 3) was prepared by using parabenzylbiphenyl instead of compound (A) in Liquid D and Liquid E and applying the coating method in (I).

[Recording paper performance table - 7 Dynamic color development test table - 8 Static color development test chart - 9 As is clear from Tables 7 to 9, the color development of the thermal recording paper of the present invention is different from that of the conventional thermal recording paper ( It was superior to Comparative Example 3). Lightfastness of the thermal recording paper of the present invention.

The moisture resistance and plasticizer resistance of conventional thermal recording paper (Comparative Example 3)
) was superior to the others.

Furthermore, among the coating methods, method (Vl) was the most excellent for producing thermal recording paper.

[Effects of the Invention] The heat-sensitive recording material containing the sensitizer of the present invention has significantly better coloring sensitivity and whiteness (background fog) than conventional materials.

Additionally, the image area provides high quality performance such as light fastness, moisture resistance and plasticizer resistance.

[Brief explanation of drawings]

7 to 7 are explanatory views (cross-sectional views) of the heat-sensitive recording material of the present invention. Process: Support, 2: Layer containing a mixture of compound (A), color former and color developer, 3: Layer containing a mixture of compound (A) and color former, 4: Compound (A) ) and a color developer, 5... a layer containing a mixture of a color former and a color developer, 6
... Compound (A) layer, 7... Color former layer, 8
・・・Developer layer

Claims (1)

[Claims] 1. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (1) [In the formula, R is a hydrocarbon group having 6 or less carbon atoms; Y is a lower alkylene group; Z is a -R group ( R is a hydrocarbon group having 6 or less carbon atoms), -OR group, -CONHR group, -COR group,
A sensitizer comprising a compound (A) represented by NO_2 group, CN group or halogen atom; n is an integer of 0, 1 or 2. 2. A heat-sensitive recording material which has an electron-donating colorless coloring agent and an electron-accepting color-developing substance on a support and which develops color by heat melting, characterized by containing the sensitizer according to claim 1. Heat-sensitive recording material. 3. The heat-sensitive recording material is a layer containing a mixture of an electron-donating colorless color former and an electron-accepting color developing substance on a support, and a layer of a compound (A) represented by general formula (1) is laminated thereon. The material according to claim 2, characterized in that it is made of. 4. A layer in which the heat-sensitive recording material is a mixture of a compound (A) represented by the general formula (1) and an electron-donating colorless coloring agent on a support;
3. The material according to claim 2, further comprising a layer containing a mixture of the compound (A) and an electron-accepting color developing substance. 5. A layer in which the heat-sensitive recording material is a mixture of a compound (A) represented by the general formula (1) and an electron-accepting color developing substance on a support;
3. The material according to claim 2, further comprising a layer containing a mixture of the compound (A) and an electron-donating colorless coloring agent.