JP2672183B2 - Thermal recording material - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a heat-sensitive recording material, and more specifically, to an electron-donating colorless dye having improved color developability, raw storability, and stability of a color image. The present invention relates to a heat-sensitive recording material in which a color forming layer containing an electron-accepting compound is provided on a support.

(Prior Art) Recording materials using an electron-donating colorless dye and an electron-accepting compound are already well known as pressure-sensitive paper, heat-sensitive paper, photosensitive pressure-sensitive paper, energized heat-sensitive recording paper, heat-sensitive transfer paper and the like. For example, British Patent No. 2,140,449, U.S. Patent No. 4,480,052, U.S. Patent No. 4,436,920, JP-B-60-23992, JP-A-57-179836
Nos. 60-123556 and 60-123557. In particular, heat-sensitive recording materials are JP-B-43-4160 and JP-B-45-1403.
No. 9 and other publications. These thermal recording systems are applied to various fields such as facsimile, printer, label, etc.
Needs are expanding. However, the heat-sensitive recording material has a drawback that fogging is caused by a solvent and the like, and a color-forming body is discolored and discolored by oils and fats, chemicals, etc., so that labels, slips, word processing paper, plotters and the like are used. In the field of paper and the like, the commercial value has been significantly impaired. The present inventors have focused on the oil-donating colorless dye and the electron-accepting compound, paying attention to their oil solubility, water solubility, partition coefficient, pKa, polarity of substituents, and position of substituents. We have pursued the development of materials for recording materials and recording materials. However, providing these resistances has caused a problem that the sensitivity is significantly reduced.

(Object of the Invention) An object of the present invention is to provide a heat-sensitive recording material of high print quality, which is excellent in raw storability and stability of a color image.

(Structure of the Invention) The object of the present invention is (1) a thermosensitive recording material comprising a support and a thermosensitive coloring layer containing an electron-donating colorless dye and an electron-accepting compound, wherein an aliphatic group is contained in the thermosensitive coloring layer. Having an amide or ureido compound and having the following general formula [I]
A heat-sensitive recording material containing a compound represented by (R ¹ has an alkyl group having 8 or more carbon atoms, R ² has 1 carbon atom
To 6 represent an alkyl group or a cycloalkyl group, and R ³ represents a lower alkyl group. (2) The heat-sensitive recording material according to claim (1), wherein the electron-accepting compound contains a salicylic acid derivative having an aryloxyalkyloxy group as a substituent or a metal salt thereof.

Among the aliphatic amide or ureido compound compounds according to the present invention, the aliphatic amide or ureido compound having 12 to 24 carbon atoms is preferable. Specifically, stearic acid amide, parimitinic acid amide, oleic acid amide, stearyl urea,
Examples include palmityl urea. Further, N-substituted amide compounds such as methylol stearic acid amide and ethylenebisstearic acid amide are also included.

In the present invention, other sensitizers may be used in combination. Examples of sensitizers include JP-A-58-57989 and JP-A-58-870.
The compounds disclosed in JP-A No. 94, JP-A-63-39375 and the like can be mentioned. Aromatic ethers (particularly benzyl ethers, di (substituted phenoxy) alkanes), esters, aromatic amides and ureides are typical examples.

Among the compounds represented by the compound [I] according to the present invention,
R ¹ is preferably a linear alkyl group having 8 or more carbon atoms.

Specifically, 2-anilino-3-methyl-6-N-cyclohexyl-N-octylaminofluorane, 2-anilino-3-methyl-6-N-cyclohexyl-N-nonylaminofluorane, 2-anilino -3-Methyl-6-N
-Cyclohexyl-N-decylaminofluorane, 2-anilino-3-methyl-6-N-cyclohexyl-N-dodecylaminofluorane, 2-anilino-3-methyl-6
-N-cyclohexyl-N-pentadecylaminofluorane, 2-anilino-3-methyl-6-N-cyclohexyl-N-octadecylaminofluorane, 2-anilino-
3-Methyl-6-N-ethyl-N-dodecylaminofluorane, 2-anilino-3-methyl-6-N-butyl-N
-Dodecylaminofluorane and the like.

In the present invention, it is necessary that the compound [I] accounts for 50% by weight or more of the electron donating colorless dye. Under the conditions described above, it can be used in combination with another electron donating colorless dye. Examples of the electron donating colorless dye that can be used in combination are shown below.

Examples of the electron-donating colorless dyes include triphenylmethanephthalide compounds, fluorane compounds, phenothiazine compounds, indolylphthalide compounds, leucoolamine compounds, rhodaminelactam compounds, triphenylmethane compounds, There are various compounds such as triazene compounds, spiropyran compounds, and fluorene compounds. Specific examples of phthalides are described in U.S. Reissue Patent Specification No.
No. 23,024, U.S. Pat.Nos. 3,491,111, 3,491,1
No. 12, No. 3,491,116 and No. 3,509,174, specific examples of fluoranes are described in US Pat.
No. 3,627,787, No. 3,641,011, No. 3,462,828, No. 3,681,390, No. 3,920,510, No. 3,959,571,
Specific examples of spiro dipyrans include U.S. Pat. No. 3,971,80
No. 8, pyridine compounds and pyrazine compounds are described in U.S. Pat.Nos. 3,775,424, 3,853,869 and 4,246,31.
No. 8 and specific examples of fluorene compounds are Japanese Patent Application No. 61-240989.
No. etc.

Among them, 2-arylamino-3-H, halogen, alkyl or alkoxy-6-substituted aminofluorane which is black is particularly effective.

As specific examples, for example, 2-anilino-3-methyl-6-diethylaminofluoran, 2-anilino-3-methyl-6-N-cyclohexyl-N-methylaminofluoran, 2-p-chloroanilino-3-methyl-6 -Dibutylaminofluoran, 2-anilino-3-methyl-6-dioctylaminofluoran, 2-anilino-3-chloro-6-diethylaminofluoran, 2-anilino-3-methyl-6-N-ethyl-N
-Isoamylaminofluorane, 2-anilino-3-methoxy-6-dibutylaminofluorane, 2-o-chloroanilino-6-dibutylaminofluorane, 2-p-chloroanilino-3-ethyl-6-N-ethyl- N-isoamylaminofluorane, 2-o-chloroanilino-6-p-
Butylanilinofluorane, 2-anilino-3-pentadecyl-6-diethylaminofluorane, 2-anilino-3
-Methyl-6-N-methyl-N-γ-ethoxypropylaminofluorane, 2-anilino-3-methyl-6-N-
Ethyl-N-γ-ethoxypropylaminofluorane, 2
-Anilino-3-methyl-6-N-ethyl-N-γ-propoxypropylaminofluorane, 2-anilino-3-
Ethyl-6-dibutylaminofluorane, 2-o-toluidino-3-methyl-6-diisopropylaminofluorane, 2-anilino-3-methyl-6-N-isobutyl-N
-Ethylaminofluorane, 2-anilino-3-methyl-
6-N-ethyl-N-tetrahydrofurfurylaminofluorane, 2-anilino-3-chloro-6-N-ethyl-
Examples include N-isoamylaminofluorane.

Examples of the electron-accepting compound according to the present invention include salicylic acid derivatives, metal salts of aromatic carboxylic acids, phenol derivatives, phenol resins, novolac resins, metal-treated novolac resins, metal complexes, acid clay and bentonite. Can be mentioned.

Examples of these are Japanese Patent Publication Nos. 40-9309 and 45-14039.
No. 5, JP-A 52-140483, JP-A 48-51510, JP-A 5
7-210886, JP-A-58-87089, JP-A-59-11286
JP-A-60-176795, JP-A-61-95988 and the like.

Some examples of these are 4-tert-butylphenol, 4-phenylphenol, 4-hydroxydiphenoxide-α-naphthol, β-naphthol, hexyl-4-hydroxybenzoate, 2,2′-dihydroxyphenyl, 2 , 2-Bis (4-hydroxyphenyl) propane (bisphenol A), 4,4 'isopropylidene bis (2-methylphenol), 1,1'-bis- (3-chloro-4-hydroxyphenyl) cyclohexane, 1 , 1'-Bis (3-chloro-4-hydroxyphenyl) -2-ethylbutane, 4,4'-secondary-isooctylidene diphenol, 4-tert-octylphenol, 4,4'-sec-
Butylidene diphenol, 4-p-methylphenylphenol, 4,4'-impentylidenephenol, 4,4'-methylcyclohexylidenediphenol, bis (3-aryl-4-hydroxyphenyl) sulfone, 4-hydroxy Phenyl-3'4 'dimethylphenyl sulfone, 4- (4
-Isopropoxyphenylsulfonyl) phenol, 4,
4'-dihydroxydiphenyl sulfide, 1,4-bis- (4'-hydroxycumyl) benzene, 1,3-bis-
(4'-Hydroxycumyl) benzene, 4,4'-thiobis (6-tert-butyl-3-methylphenol), 4,4'-
Dihydroxydiphenyl sulfone, hydroquinone monobenzyl ether, 4-hydroxybenzophenone, 2,4-
Dihydroxybenzophenone, polyvinylbenzyloxycarbonylphenol, 2,4,4'-trihydroxybenzophenone, 2,2'4,4'-tetrahydroxybenzophenone, 4-hydroxyphthalic acid, dimethyl-4-hydroxybenzoic acid methyl ester, 2, 4,4'-trihydroxydiphenylsulfone, 1,5-bis-p-hydroxyphenylpentane, 1,6-bis-p-hydroxyphenoxyhexane, 4-
Tolyl hydroxybenzoate, 4-hydroxybenzoic acid α-
Phenylbenzyl ester, 4-hydroxybenzoic acid phenylpropyl, 4-hydroxybenzoic acid phenethyl, 4-hydroxybenzoic acid-p-chlorobenzyl, 4-hydroxybenzoic acid-p-methoxybenzyl, 4-hydroxybenzoic acid benzyl ester, 4 -Hydroxybenzoic acid-m-chlorobenzyl ester, 4-hydroxybenzoic acid-β-phenethyl ester, 4-hydroxy-2 ', 4'-dimethylphenyl sulfone, β-phenethyl orserinate, cinnamyl orserinate, orserine Acid-o-chlorophenoxyethyl ester, o-ethylphenoxyethyl orserinate, o-phenylphenoxyethyl orserinate, m-phenylphenoxyethyl orserinate, 2,4
-Dihydroxybenzoic acid-β-3'-t-butyl-4 '
-Hydroxyphenoxyethyl ester, 1-t-butyl-4-p-hydroxyphenylsulfonyloxybenzene, 4-N-benzylsulfamoylphenol, 2,4-dihydroxybenzoic acid-β-phenoxyethyl ester,
2,4-Cihydroxy-6-methylbenzoic acid benzyl ester, bis-4-hydroxyphenylacetic acid methyl ester, ditolylthiourea, 4,4'-diacetyldiphenylthiourea, 3-phenylsalicylic acid, 3-cyclohexylsalicyls, 3, 5-di-tert-butylsalicylic acid, 3-methyl-5-
Benzylsalicylic acid, 2-phenyl-5- (α, α-dimethylbenzyl) salicylic acid, 3,5-di- (α-methylbenzyl) salicylic acid, 5-t-octylsalicylic acid, 3,5-di-t-butylsalicylic acid , 3-Chloro-5-cumylsalicylic acid, 3-methyl-5-t-octylsalicylic acid, 3-methyl-5-α-methylbenzylsalicylic acid, 3-methyl-5
-Cumylsalicylic acid, 3,5-di-t-amylsalicylic acid, 3
-Phenyl-5-benzylsalicylic acid, 3-phenyl-5
-T-octylsalicylic acid, 3-phenyl-5-α-methylbenzylsalicylic acid, 3,5-di-t-octylsalicylic acid, 3,5-bis (α-methylbenzyl) salicylic acid, 3,5-
Dicumylsalicylic acid, 4-methyl-5 (α-methylbenzyl) salicylic acid, 4-methyl-5-cumylsalicylic acid, 3-
(Α-methylbenzyl) -6-methylsalicylic acid, 3-
(Α-Methylbenzyl) -6-phenylsalicylic acid, 3-
Triphenylmethylsalicylic acid, 3-diphenylmethylsalicylic acid, 4-n-dodecylsalicylic acid, 4-t-dodecylsalicylic acid, 4-n-dodecylsalicylic acid, 4-n-pentadecylsalicylic acid, 4-n-heptadecylsalicylic acid, 5-
(1,3-Diphenylbutyl) -salicylic acid, 5-n-octadecylsalicylic acid, 4-pentadecylsalicylic acid, 3,5-
Bis (α-methylbenzyl) salicylic acid, 3,5-bis-t
-Octylsalicylic acid, 5-octadecylsalicylic acid, 5-
α- (p-α-methylbenzylphenyl) ethylsalicylic acid, 3-α-methylbenzyl-5-t-octylsalicylic acid, 5-tetradecylsalicylic acid, 4-hexyloxysalicylic acid, 4-cyclohexyloxysalicylic acid, 4-salicyloxy Salicylic acid, 4-decyloxysalicylic acid, 4-
Dodecyloxysalicylic acid, 4-tetradecyloxysalicylic acid, 4-pentadecyloxysalicylic acid, 4-hexadecyloxysalicylic acid, 4-octadecyloxysalicylic acid, 4-icosyloxysalicylic acid, 4-triacontyloxysalicylic acid, 4-oleyloxy Salicylic acid, 4-β-
Phenethyloxysalicylic acid, 4-β-dodecyloxyethoxysalicylic acid, 4- (12-chlorododecyl) oxysalicylic acid, 4-β-N-stearoylaminoethoxysalicylic acid, 4-β-N-myrinutoylaminoethoxysalicylic acid, 4- β-perfluorohexylethoxy salicylic acid, 4-dodecyloxy-5-chlorosalicylic acid, 4-dodecyloxy-5-methylsalicylic acid, 4-dodecyloxy-6-methylsalicylic acid, 4-dodecyloxy-6-phenylsalicylic acid, 4 -Methoxy-6-dodecyloxysalicylic acid, 6-octadecyloxysalicylic acid, 4-pt-
Octylphenyloxysalicylic acid, 4-p-dodecyloxyphenyloxysalicylic acid, 4-p-chlorophenoxy-6-butylsalicylic acid, 4-p-phenylphenoxysalicylic acid, 4-p-N-myristoylcarbamoylphenyloxysalicylic acid, 4-benzyl There are oxy-6-dodecyloxysalicylic acid, 5-dodecylsulfonylsalicylic acid, 5-dodecylsulfosalicylic acid, 3-methyl-5-dodecylsulfosalicylic acid and the like.

In the present invention, as the electron-accepting compound, a salicylic acid derivative having an aryloxyalkyloxy group represented by the following general formula [II] or a metal salt thereof is particularly preferable.

In the above formula, Ar represents an aryl group, X represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, M represents an n-valent metal atom, and m and n represent integers.

The alkyl group represents a saturated or unsaturated alkyl group or cycloalkyl group, which has a substituent such as an aryl group, an alkoxy group, an aryloxy group, a halogen atom, an acylamino group, an aminocarbonyl group or a cyano group. Also, the aryl group represents a phenyl group, a naphthyl group, or a heteroaromatic ring group, and these are an alkyl group, an alkoxy group, an aryloxy group, a halogen atom, a nitro group, a cyano group, a substituted carbamoyl group, a substituted sulfamoyl group. It may have a substituent such as a group, a substituted amino group, a substituted oxycarbonyl group, a substituted oxysulfonyl group, a thioalkoxy group, an arylsulfonyl group, or a phenyl group.

6 to 22 carbon atoms among the substituents represented by Ar in the above formula
Aryl groups are preferred, and among the substituents represented by X, a hydrogen atom, an alkyl group having 1 to 9 carbon atoms, and a carbon atom of 1
~ 5 alkoxy group, chlorine atom and fluorine atom are preferable, and among the metal atoms represented by M, zinc, aluminum,
Magnesium and calcium are preferred.

Among the substituents of the aryl group represented by Ar, an alkoxy group having 1 to 12 carbon atoms, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 16 carbon atoms, a halogen atom,
A phenyl group or an alkoxycarbonyl group is preferred.

Preferred examples of the aryl group represented by Ar include a phenyl group, a tolyl group, an ethylphenyl group, a propylphenyl group, a butylphenyl group, a cyclohexylphenyl group,
Octylphenyl group, nonylphenyl group, dodecylphenyl group, benzylphenyl group, phenethylphenyl group,
Cumylphenyl group, xylyl group, diphenethylphenyl group, methoxyphenyl group, ethoxyphenyl group, benzyloxyphenyl group, octyloxyphenyl group, dodecyloxyphenyl group, chlorophenyl group, fluorophenyl group, phenylphenyl group, hexyloxycarbonylphenyl group , A benzyloxycarbonylphenyl group,
Examples thereof include dodecyloxycarbonylphenyl group, naphthyl group, methylnaphthyl group, chloronaphthyl group and the like.

The substitution position of the aryloxyalkyloxy group is COO
The para position is particularly preferable for the (H or M _{1 / m} ) group.

From the viewpoint of water insolubility, the salicylic acid derivative according to the present invention is preferably a compound having 12 or more total carbon atoms, and particularly preferably 14 or more.

The recording material using the salicylic acid derivative according to the present invention has a sufficient coloring density and the coloring dye is remarkably stable, and does not undergo discoloration even after long-time light irradiation, heating or humidification, so that the recording material can be used for a long time. It is particularly advantageous in terms of preservation. Further, when used in a heat-sensitive recording material, there is no defect that the uncolored part is colored by a solvent or the colored material is discolored by oils or chemicals, so it is ideal as an electron-accepting compound for a recording material. Has performance close to.

Next, specific examples of the electron-accepting compound according to the present invention will be shown.

4-β-phenoxyethoxysalicylic acid, 4- (4-phenoxybutoxy) salicylic acid, 4- (6-phenoxyhexyloxy) salicylic acid, 4- (5-phenoxyamyloxy) salicylic acid, 4- (8-phenoxyoctyloxy) salicylic acid , 4- (10-phenoxydecyloxy) salicylic acid, 4-β-p-tolyloxyethoxysalicylic acid, 4-β-m-tolyloxyethoxysalicylic acid, 4-β
-P-ethylphenoxyethoxysalicylic acid, 4-β-p
-Isopropylphenoxyethoxysalicylic acid, 4-β-
pt-butylphenoxyethoxysalicylic acid, 4-β-
p-cyclohexylphenoxyethoxysalicylic acid, 4-
β-pt-octylphenoxyethoxysalicylic acid, 4
-Β-p-nonylphenoxyethoxysalicylic acid, 4-β
-P-dodecylphenoxyethoxysalicylic acid, 4-β-
p-benzylphenoxyethoxysalicylic acid, 4- (2-
p-α-phenethylphenoxyethoxy) salicylic acid, 4
-Β-o-methoxyphenoxyethoxysalicylic acid, 4-
β-p-cumyloxyethoxysalicylic acid, 4-β- (2,
4-dimethylphenoxy) ethoxysalicylic acid, 4-β-
(3,4-Dimethylphenoxy) ethoxy salicylic acid, 4-
β- (3,5-dimethylphenoxy) ethoxysalicylic acid,
4-β- (2,4-bis-α-phenethylphenoxy) ethoxysalicylic acid, 4-β-p-methoxyphenoxyethoxysalicylic acid, 4-β-p-ethoxyphenoxyethoxysalicylic acid, 4-β-p-benzyloxy Phenoxyethoxysalicylic acid, 4-β-p-dodecyloxyphenoxyethoxysalicylic acid, 4-β-p-chlorophenoxyethoxysalicylic acid, 4-β-p-phenylphenoxyethoxysalicylic acid, 4-β-p-cyclohexylphenoxyethoxysalicylic acid, 4 -Β-p-benzyloxycarbonylphenoxyethoxysalicylic acid, 4-β-p-dodecyloxycarbonylphenoxyethoxysalicylic acid, 4-β
-Naphthyl (2) oxyethoxy salicylic acid, 5-β-p
-Ethylphenoxyethoxy salicylic acid, 4-β-phenoxyethoxy-6-methylsalicylic acid, 4-β-phenoxyethoxy-6-chlorosalicylic acid, 4-β-phenoxyisopropyloxysalicylic acid, 4-ω-p-methoxyphenoxy-3- Oxa-n-pentyloxysalicylic acid, 4-ω-p-methoxyphenoxy-3-oxa-n-
There are pentyloxysalicylic acid and the like and metal salts thereof, and these are used alone or as a mixture.

The metal salt according to the present invention is preferably a salt with a divalent or trivalent metal, for example, a metal selected from zinc, magnesium, barium, calcium, aluminum, tin, titanium, nickel, cobalt, manganese, iron and the like, Zinc compounds are particularly preferred.

The electron-accepting compound is 50 to 800 of the electron-donating colorless dye.
It is preferable to use 100% by weight, more preferably 100
~ 500% by weight.

A general electron-accepting compound may be mixed with the salicylic acid derivative which is the electron-accepting compound according to the present invention. The mixing ratio is 10 to 10 with respect to the salicylic acid derivative.
It is preferable to mix at a ratio of 100% by weight. Further, two or more of the above electron accepting compounds may be used in combination.

According to the present invention, the dispersed particle size of the salicylic acid derivative or its metal salt after being atomized in a sand mill or the like is preferably 3 μm or less, preferably 2 μm or less in order to obtain color development sensitivity.

Next, a method for producing a typical thermosensitive coloring layer of the present invention will be described.

Electron-donating colorless dye, electron-accepting compound, sensitizer
It is dispersed to several microns or less using a ball mill, sand mill or the like together with an aqueous solution of a water-soluble polymer such as polyvinyl alcohol. The sensitizer is added to either or both of the electron-donating colorless dye and the electron-accepting compound, and is dispersed at the same time, or in some cases, a eutectic with the electron-donating colorless dye or the electron-accepting compound is prepared in advance. , May be dispersed.

These dispersions are mixed after dispersion, and if necessary, pigments, surfactants, binders, metal soaps, waxes, antioxidants, ultraviolet absorbers and the like are added to form a heat-sensitive coating solution.

The obtained heat-sensitive coating liquid is applied and dried on a high-quality paper, a high-quality paper having an undercoat layer, a synthetic paper, a plastic film, and the like, and then imparts smoothness by a calendering treatment to obtain a desired heat-sensitive recording material. At this time, it is particularly preferable from the viewpoint of dot reproducibility to use a support having a smoothness defined by JIS-8119 of 500 seconds or more, particularly 800 seconds or more. To obtain a support with a smoothness of 500 seconds or more, use a highly smooth material such as synthetic paper or plastic film. Provide an undercoat layer containing a pigment as the main component on the support.

There are means such as using a super calender to increase the smoothness of the support.

As the binder, a compound that is soluble in 5% by weight or more in water at 25 ° C. is preferable, and specifically, polyvinyl alcohol (including modified polyvinyl alcohol such as carboxy-modified, itaconic acid-modified, maleic acid-modified, and silica-modified) , Methyl cellulose, carboxymethyl cellulose, starches (including modified starch), gelatin, gum arabic, casein, styrene-maleic anhydride copolymer hydrolyzate, polyacrylamide, saponified vinyl acetate-polyacrylic acid copolymer, etc. Can be given. These binders are used not only for dispersion but also for the purpose of improving the coating strength.
A latex binder of a synthetic polymer such as a butadiene copolymer, a vinyl acetate copolymer, an acrylonitrile / butadiene copolymer, a methyl acrylate / butadiene copolymer, or polyvinylidene chloride can be used together. If necessary, a crosslinking agent for an appropriate binder may be added depending on the kind of the binder.

Examples of the pigment include calcium carbonate, barium sulfate, lithopone, wax, kaolin, silica, and amorphous silica.

As the metal soap, higher fatty acid metal salts are used, such as zinc stearate, calcium stearate, and aluminum stearate.

Further, if necessary, a surfactant, an antioxidant, an antistatic agent, an ultraviolet absorber, an antifoaming agent, a conductive agent, a fluorescent dye, a coloring dye, etc. may be added.

The applied heat-sensitive recording material is dried, subjected to a treatment such as a calender, and provided for use.

Further, a protective layer may be provided on the thermosensitive coloring layer as needed. As the protective layer, any known protective layer can be used as the protective layer of the heat-sensitive recording material.

Further, if necessary, a back coat layer may be provided on the surface of the support of the thermosensitive recording material opposite to the thermosensitive coloring layer. As the back coat layer, any of those known as a back coat layer of a thermosensitive recording material can be used.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to the following Examples.

(Example-1) 2-anilino-3-methyl-6-N-cyclohexyl-N-dodecylaminofluorane as an electron-donating colorless dye, and zinc 4-β-p-methoxyphenoxyethoxysalicylate as an electron-accepting compound. Stearyl urea as a sensitizer, and 20 g of each were dispersed with a 100% 5% aqueous solution of polyvinyl alcohol (Kuraray PVA-105) in a ball mill for one day to make the average particle diameter 1.5 μm or less to obtain each dispersion. Also, 80 g of calcium carbonate was dispersed with a homogenizer together with 160 g of a 0.5% sodium hexametaphosphate solution to obtain a pigment dispersion.

Electron-donating colorless dye dispersion 5 g, electron-accepting compound dispersion 10 g, stearyl urea dispersion 10 g, and calcium carbonate dispersion were mixed at a ratio of 5 g with each dispersion prepared as described above, and 21% stearin was further added. 3 g of zinc acid emulsion was added to obtain a heat-sensitive coating liquid. This thermosensitive coloring layer coating solution
It was coated on a high-quality paper of 50 g / m ² using a wire bar so that the dry weight of the coating layer was 5 g / m ² , and dried at 50 ° C. for 1 minute to obtain a thermosensitive recording paper.

(Example-2) Instead of using 2-anilino-3-methyl-6-N-cyclohexyl-N-dodecylaminofluorane of Example-1, 2-anilino-3-methyl-6-N-cyclohexyl was used. A thermosensitive recording paper was obtained by the same method except that a thermosensitive coating liquid was prepared using -N-nonylaminofluorane.

Example 3 Instead of using 2-anilino-3-methyl-6-N-cyclohexyl-N-dodecylaminofluorane of Example-1, 2-anilino-3-methyl-6-N-cyclohexyl is used. A thermosensitive recording paper was obtained by the same method except that the thermosensitive coating liquid was prepared using -N-decylaminofluorane.

(Example-4) Instead of using the stearyl urea dispersion of Example-1, a 22% stearic acid amide dispersion (Chukyo Yushi Co., Ltd. Hi
A heat-sensitive recording paper was obtained by the same method except that the heat-sensitive coating liquid was prepared using drin F-792).

(Example-5) A thermosensitive recording paper was prepared in the same manner as in Example-1, except that bisphenol A was used in place of zinc 4-β-p-methoxyphenoxyethoxysalicylate to prepare a thermosensitive coating liquid. Got

Comparative Example-1 Instead of using 2-anilino-3-methyl-6-N-cyclohexyl-N-dodecylaminofluorane of Example-1, 2-anilino-3-methyl-6-N-cyclohexyl was used. A thermosensitive recording paper was obtained by the same method except that a thermosensitive coating liquid was prepared by using -N-methylaminofluorane.

(Comparative Example-2) Instead of using stearyl urea of Example-1, β
A heat-sensitive recording paper was obtained by the same method except that the heat-sensitive coating liquid was prepared using naphthylbenzyl ether.

Comparative Example-3 In the preparation of Example-1, bisphenol A was used instead of zinc 4-β-p-methoxyphenoxyethoxysalicylate, and β-naphthylbenzyl ether was used instead of stearyl urea. A heat-sensitive recording paper was obtained by the same method except that a heat-sensitive coating liquid was prepared.

Comparative Example-4 Instead of using 2-anilino-3-methyl-6-N-cyclohexyl-N-dodecylaminofluorane in the preparation of Example-1, 2-anilino-3-methyl-6- N-cyclohexyl-N-methylaminofluorane was used, and bisphenol A was used instead of zinc 4-β-p-methoxyphenoxyethoxysalicylate.
A heat-sensitive recording paper was obtained in the same manner as above except that a heat-sensitive coating liquid was prepared.

Comparative Example-5 Instead of using 2-anilino-3-methyl-6-N-cyclohexyl-N-dodecylaminofluorane in the preparation of Example-1, 2-anilino-3-methyl-6- N-cyclohexyl-N-methylaminofluorane was used, instead of using stearyl urea, β-
Using naphthyl benzyl ether, 4-beta
A thermosensitive recording paper was obtained by the same method except that bisphenol A was used instead of zinc -p-methoxyphenoxyethoxysalicylate to prepare a thermosensitive coating liquid.

The heat-sensitive recording paper obtained as described above is surface-treated with a calender, and the smoothness is 300 ± 50 as Beck smoothness.
The temperature was adjusted so as to be seconds, and a heat-sensitive recording material was obtained.

 The evaluation of the thermal recording paper was performed as follows.

Color density is 30 mJ with Kyocera printing tester
/ mm ² and the color density was measured with a Macbeth densitometer. The higher the value, the higher the sensitivity of the thermal recording paper.

The chemical resistance test was conducted by impregnating filter paper with ethanol and castor oil respectively and overlaying it on the color surface of the recording paper obtained by the above method, and then fog on the white background and decolorization of the color area (discoloration)
Was evaluated.

 The above results are shown in the following table.

As can be seen from the results in the table, it is understood that the recording material of the present invention has high sensitivity, does not cause fog color development or decolorization of the color development part due to chemicals, and has extremely excellent performance.

Claims (2)

(57) [Claims] 1. A thermosensitive recording material comprising a support and a thermosensitive coloring layer containing an electron-donating colorless dye and an electron-accepting compound, wherein the thermosensitive coloring layer contains an aliphatic amide or an ureido compound. A heat-sensitive recording material comprising a compound represented by the following general formula [1]. (R ¹ represents an alkyl group having 8 or more carbon atoms, R ² has 1 carbon atom
To 6 represent an alkyl group or a cycloalkyl group, and R ³ represents a lower alkyl group. ) 2. The heat-sensitive recording material according to claim 1, wherein the electron-accepting compound contains a salicylic acid derivative having an aryloxyalkyloxy group as a substituent or a metal salt thereof.