JPH01188389A - Thermal recording material - Google Patents

Abstract

PURPOSE:To obtain a thermal recording material with high color forming sensitivity, by supporting a leuco dye and a color developing substance for developing the dye into a color on heating on a base, and further providing a plurality of heat-fusible substances in the form of a mixture. CONSTITUTION:A plurality of heat-fusible substances are incorporated in the form of a mixture thereof, in a thermal recording material in which a leuco dye and a color developing substance for developing the dye into a color on heating are supported on a base. The two or more heat-fusible substances are incorported in a thermal recording layer in the form of a mixture thereof, for example, in the form of a solid solution obtained by melting the heat-fusible substances together, followed by solidification. The heat-fusible substances are desirably selected from those heat-fusible substances having melting points of 50-200 deg.C which are compatible with the dye or the color developer. When a lubricant is selected as one of the heat-fusible substances for forming the mixture with the heat-fusible substance used as a sensitizer, a thermal recording material can be obtained which has both a high color forming sensitivity and excellent matching properties. As the lubricant, a metallic salt of a higher fatty acid is preferably used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a heat-sensitive recording material, and more particularly to a heat-sensitive recording material with high color development sensitivity to which a specific thermofusible substance is added.

[Prior art]

In recent years, heat-sensitive recording materials have been required to have higher sensitivity to support high-speed recording, especially when applied to high-speed recording facsimiles, label printers, ticket vending machines, etc.
On the other hand, with the diversification of uses, there is a strong desire for a material that does not cause background fog, has good mating properties with the above-mentioned printing equipment, and is maintenance-free.

As a general technique for increasing the sensitivity of conventionally known heat-sensitive recording materials in order to meet the above-mentioned demands, a technique is used to more effectively use the thermal energy applied to the recording material for the melting and coloring reaction of the color-forming material. ■Research on materials with excellent color-forming properties as leuco dyes and color developers ■Research on thermofusible substances that dissolve one or both of leuco dyes and color developers when heated and promote color-forming reactions ■Leuco dyes and Research on an undercoat or support for more effectively consuming thermal energy in a heat-sensitive coloring layer containing a color developer as a main component.■ Research on the shape of the outermost surface to more effectively transmit heat energy to the heat-sensitive coloring layer. , research on physical properties has been conducted, and numerous proposals have been made.

In particular, thermofusible substances, so-called sensitizers, as described in ① above are technically easy to improve color development sensitivity by simply adding them to heat-sensitive recording materials with conventional configurations. It has been widely put into practical use.

However, the addition of the above-mentioned sensitizer has the disadvantage of improving color development sensitivity, but has problems such as background fogging (especially in high-temperature, high-humidity environments) and poor matching with printing equipment (particularly sticking and residue adhesion). often occurs.

This is because when the combined use of a sensitizer causes a drop in the eutectic point of the melting color reaction between the dye and color developer, the sharpness of the melting peak is lost, even at temperatures considerably lower than the original eutectic point. This is because it is in a state where it can be melted. Further, since the total amount of the thermofusible substance increases when a sensitizer is used in combination, the amount of the molten substance that adheres to the printing device (thermal head, etc.) increases. This seems to be the reason for the above-mentioned poor matching properties.

The measures to improve the above-mentioned drawbacks are to lower the eutectic point to a necessary and sufficient degree, maintain the sharpness of the melting peak, and greatly accelerate the melting color reaction with the addition of a very small amount. It is conceivable to select a sensitizer that is However, the reality is that no substance has been found that satisfies all of the above requirements.Usually, a sensitizer that is suitable for the purpose is selected mainly from the viewpoint of melting characteristics such as melting point, and is used in the heat-sensitive coloring layer. It is used in combination at a ratio of about 25 to 50 wt % based on the entire thermofusible material. That is, when a sensitizer is used in combination, the amount of thermofusible material in the heat-sensitive coloring layer usually increases by about 1.3 to 2 times compared to when no sensitizer is used. Therefore, in the prior art, when high sensitivity is to be achieved by using a sensitizer in combination, there are very few substances that can be selected as the sensitizer, and in many cases it is not possible to obtain sufficient quality for the purpose. Furthermore, it has been extremely difficult to ensure that the matching properties are not deteriorated at all by using a sensitizer in combination.

Regarding the improvement of color development sensitivity among the above-mentioned problems, for example, Japanese Patent Application Laid-Open No. 53-48751 and Japanese Patent Application Laid-open No. 54-9226
No. 2, JP-A-56-164890, JP-A-57-34
No. 995, JP-A-57-133097, JP-A-57-
146688, JP-A No. 60-85988, and JP-A No. 60-260378, etc., techniques have been disclosed that achieve this by using a dye or color developer and a thermofusible substance as a solid solution. There are some that can be expected to have sufficient effects.

However, it cannot be said that this technology satisfies the original intended characteristics in the sense that it improves color development sensitivity and also causes background fog and poor matching with printing equipment, and even if these drawbacks are accepted, There are very few and limited substances that have characteristics that can sufficiently improve color development sensitivity.

〔the purpose〕

An object of the present invention is to provide a heat-sensitive recording material with high color development sensitivity by adding a specific thermofusible substance.

In other words, when obtaining a heat-sensitive recording material that uses a thermofusible substance in combination for the purpose of increasing color development sensitivity, the range of selection of thermofusible substances that can satisfy the objective is expanded compared to the conventional technology. The present invention provides a heat-sensitive recording material that also has improved matching properties with printing equipment.

〔composition〕

According to the present invention, in a heat-sensitive recording material in which a leuco dye and a color developing substance that causes the leuco dye to develop color when heated are supported on a support, a plurality of thermofusible substances are further added in the form of a mixture. Provided is a heat-sensitive recording material characterized by containing the following.

That is, in the present invention, the coloring sensitivity can be improved by incorporating two or more types of thermofusible substances in the heat-sensitive recording layer as a mixture in the form of a solid solution obtained by solidifying after heating eutectic. The goal is to achieve the following.

In this case, the thermofusible substance preferably has a melting point of 60
It should be selected from substances that are compatible with dyes or color developers within the temperature range of ℃ to 200℃, and mixtures obtained from such substances are preferably selected from the leuco dye and color developer used. has a melting point lower than that of the substance;
The eutectic point or melting peak shape of the entire thermofusible material forming the thermosensitive coloring layer has sufficient solubility for both the leuco dye and the color developing substance, and the desired coloring sensitivity and storage characteristics ( The mixture should be prepared so that it does not cause background fogging.

With the conventional technology, it would have been extremely difficult to search for a thermofusible substance that has all the necessary properties as described above, but according to the present invention, it is possible to find a thermofusible substance that has all the necessary properties. Since the purpose is to be achieved by using a mixture of thermofusible substances, there are very few restrictions on usable thermofusible substances, and the range of selection can be dramatically improved.

The mixture of thermofusible substances used in the present invention instantly melts when heated and improves color development sensitivity by melting the leuco dye and the color developing substance, so the mixture is formed. The above object cannot be fully satisfied if a plurality of thermofusible substances are melted separately. Therefore, in the present invention, it is desirable to prepare a mixture of thermofusible substances by the following method.

■A method of mixing two or more types of thermofusible substances in a hot molten state, cooling and solidifying, and then pulverizing.■Mixing two or more types of thermofusible substances in a hot molten state and then pouring them into a solvent that does not dissolve them. Method of emulsifying by stirring and dispersing two or more thermofusible substances. After dissolving two or more thermofusible substances in an organic solvent that dissolves at least one of them, coprecipitation is carried out by pouring them into a large amount of solvent that does not dissolve them. Method of producing and pulverizing one or more thermofusible substances in a thermally molten state or dissolved in an organic solvent and spraying the fine powder of another thermofusible substance in the form of a mist to form a fine powder on its surface. In the present invention, a thermofusible substance mixture can be obtained as a sensitizer useful for heat-sensitive recording materials by the method described above. If a lubricant conventionally used in this type of heat-sensitive recording material is selected as one of the substances, a heat-sensitive recording material having high coloring sensitivity and excellent matching properties can be obtained.

In this case, a metal salt of a higher fatty acid is preferably used as a lubricant, but simply adding a metal salt of a higher fatty acid as in the past does not improve the matching property as in the present invention, so it is used as a sensitizer. A significant improvement in matching properties can only be achieved by using the material as a mixture with other thermofusible materials according to the method described above.

The reason for this is not clear, but when the sensitizer, which was a factor that caused a considerable deterioration of matching performance in conventional technology, is melted by heating, it instantly melts together with the lubricant, which has the property of improving matching performance. This is thought to be because it contributes to improving sexual performance.

The present invention is characterized in that by forming and utilizing a plurality of thermofusible substances as one substance, it is possible to impart unprecedented excellent properties. If the compound occupies 90 wt% or more of the total weight, it will be difficult to bring out sufficient advantages. For this reason, each compound forming the mixture must be constituted so as to account for at least LOtgt% or more of the total.
It is difficult to obtain sufficient properties as a thermofusible material.

Examples of the thermofusible substance used in the present invention include the following.

Higher fatty acids such as stearic acid, palmitic acid, myristic acid, lauric acid, and behenic acid and their monoamides, hydrazides, bisamides such as ethylenebisstearylamide, N,N'-didecyl urea, N-decyl-N'-
lauryl urea, N-decyl-N'-eicosyl urea, N
, N'-dilauryl urea, N-lauryl-N'-stearylurea, N, N'-distearylurea, N-stearyl-N'-tocosyl urea, N, N'-distearylurea, N-stearyl-N' - triacontylurea, methylene-bis(laurylcarbamoylamide), ethylene-bis(pentadecylcarbamoylamide), n-propylene-bis(eicosylcarbamoylamide),
1,3-cyclohexylene-bis(octadecylcarbamoylamide), m-phenylene-bis(tocodylcarbamoylamide), I-xylylene-bis(octadecylcarbamoylamide), m-xylylene-bis(tocodylcarbamoylamide) Urea compounds such as
ρ-Benzyl biphenyl, terphenyl, triphenylmethane, P-benzyloxybenzoate, P-toluenesulfonic acid phenyl ester, β-benzyloxynaphthalene, β-naphthoic acid penyl ester, 1-
Hydroxy-2-naphthoic acid phenyl ester, 1-hydroxy-2-naphthoic acid methyl ester, diphenyl carbonate, terephthalic acid dibenzyl ester, terephthalic acid dimethyl ester, 1,4-dimethoxynaphthalene, 1,4-jethoxynaphthalene, 1 .4-dibenzyloxynaphthalene, 1,2-bis(phenoxy)ethane, 1,2-bis(3-methylphenoxy)ethane,
1.2-bis(4-methylphenoxy)ethane, ■, 4
-bis(phenoxy)butane, 1,4-(phenoxy)
-2-butene, dibenzoylmethane, 1,4-bis(phenylthio)butane, 1,4-bis(phenylthio)-
2-butene, 1,3-bis(2-vinyloxyethoxy)benzene, 1,4-bis(2-vinyloxyethoxy)benzene, p-(2-vinyloxyethoxy)biphenyl, p-aryloxybiphenyl, P -propargyloxybiphenyl, dibenzoyloxymethane, 1.3
-dibenzoyloxymethane, dibenzyl disulfide, ■, 1-diphenylethanol, 1,1-diphenylpropatol, p-(benzyloxy)benzyl alcohol, 1,3-diphenoxy-2-propatol, N-
Octadecylcarbamoyl=p-methoxycarbonylbenzene, N-octadecylcarbamoylbenzene, etc.

In particular, as the lubricant, zinc salts, calcium salts, magnesium salts, lead salts, cadmium salts, barium salts, aluminum salts, etc. of the higher fatty acids are preferably used.

The leuco dyes used in the present invention may be applied singly or in a mixture of two or more types. As such leuco dyes, those applied to this type of heat-sensitive material can be arbitrarily applied. For example, triphenyl Leuco compounds of methane-based, fluoran-based, phenothiazine-based, auramine-based, and spiropyran-based dyes are preferably used. Specific examples of such leuco dyes include those shown below.

3.3-bis(p-dimethylaminophenyl)-phthalide, 3.3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide (also known as crystal violet lactone), 3.3-bis(p- dibutylaminophenyl)-6-dibutylaminophenyl, 3.3-bis(p-dimethylaminophenyl)-6-chlorophthalide, 3.3-bis(p-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6- Chlorfluorane, 3-dimethylamino-5,7-dimethylfluorane, 3
-N-methyl-N-isobutyl-6-methyl-7-anilinofluorane, 3-N-ethyl-N-amyl-6-methyl-7-anilinofluorane, 3-diethylamino-7-glorofluorane, 3 -diethylamino-7-methylfluoran, 3-diethylamino-7,8-benzfluorane, 3-diethylamino-
6-Methyl-7-chlorofluorane.

3-(N-p-tolyl-N-dithylamino)-6-methyl-7-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2-(N-(3'- trifluoromethylphenyl)amino)-6-dinithylaminofluorane, 2-(
3,6-bis(diethylamino)-9-(o-chloroanilino)xantylbenzoic acid lactam), 3-diethylamino-6-methyl-7-(m-trichloromethylanilino)fluoran, 3-diethylamino-7-(o -chloroanilino)fluoran, 3-dibutylamino-7-(o-chloroanilino)fluoran, 3-N-methyl-N-amylamino-6-methyl-7-
Anilinofluorane, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl- 7-(2', 4'-
dimethylanilino) fluorane.

3-(N,N-diethylamino)-5-methyl-7-(
N,N-dibenzylamino)fluoran, benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrylospirane, 6'-bromo-3'-methoxy-benzoindolino-pyrylospirane, 3-(2 '-Hydroxy-47-dimethylaminophenyl)-3-(2'-methoxy-5'-chlorophenyl)phthalide, 3-(2'-hydroxy-4'-dimethylaminophenyl)-3-(2'-methoxy -5'-nitrophenyl) phthalide, 3-(2'-hydroxy-47-dimethylaminophenyl)-3-(2'-methoxy-5'-methylphenyl) phthalide, 3-(2'-methoxy-4 '-dimethylaminophenyl)-3-(2'-hydroxy-4'-chloro-5'
-methylphenyl)phthalide, 3-morpholino-7-(N-propyl-trifluoromethylanilino)fluorane, 3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7-( N-benzyl-trifluoromethylanilino)fluorane, 3-pyrrolidino-7-(di-ρ-glolphenyl)methylaminofluorane.

3-diethylamino-5-chloro-7-(α-phenylethylamino)fluoran, 3-(N-ethyl-P-toluidino)-7-(α-phenylethylamino)fluorane, 3-diethylamino-7-(o -methoxycarbonylphenylamino)fluoran, 3-diethylamino-4-methyl-7-(α-phenylethylamino)fluoran.

3-diethylamino-7-piperidinofluorane, 2-
Chloro-3-(N-methyltoluidino)-7-(p-n
-butylanilino)fluorane, 3-(N-methyl-N-isopropylamino)-6-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 3.6-bis (dimethylamino)fluorene spiro(9
゜3')-6'-dimethylaminophthalide, 3-(N-
benzyl-N-cyclohexylamino)-5,6-penzo-7-α-naphthylamino-4'-bromofluorane, 3-diethylamino-6-chloro-7-anilinofluorane, 3-N-ethyl-N -(2-ethoxypropyl)amino-6-methyl-7-anilinofluorane, 3-N-ethyl-N-tetrahydrofurfurylamino-
6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-mesitidino 4', 5'-benzofluorane, and the like.

In addition, as the color developer used in the present invention, various electron-accepting compounds that cause the leuco dye to undergo catalytic color development are preferably used, such as phenolic compounds, thiophenolic compounds, thiourea derivatives, organic acids, and metal salts thereof. applied,
Specific examples include those shown below.

4.4'-isopropylidene bisphenol, 4.4
′ -isopropylidene bis(0-methylphenol)
, 4.4'-Secondary-butylidene bisphenol 4.4'-Isopropylidene bis(2-tert-
butylphenol), 4.4'-cyclohexylidene diphenol, 4.4
′ -isopropylidene bis(2-chlorophenol)
.

2.2'-methylenebis(4-methyl-6-tert-butylphenol), 2.2'-methylenebis(4-ethyl-6-tert-butylphenol), 4.4'-butylidenebis(6-tert-butyl-2 -methylphenol), 1.1.3-tris(2-methyl-4-hydroxy-
5-tert-butylphenyl)butane, 1.1.3
-tris(2-methyl-4-hydroxy-5-cyclohexylphenyl)butane, 4,4' -thiobis(6-tert-butyl-2-
methylphenol), 4.4'-diphenolsulfone, 4.4'-isopropoxy-4'-hydroxydiphenylsulfone, 4-benzyloxy-41-hydroxydiphenylsulfone, 4.4'-diphenolsulfoxide, P-hydroxy Isopropyl benzoate, benzyl P-hydroxybenzoate, benzyl protocatechuate.

Stearyl gallate, lauryl gallate, octyl gallate, 1,7-bis(4-hydroxyphenylthio)-3,5
-dioxahebutane, (1), 5-bis(4-hydroxyphenylthio)-3-oxapentane, 1,3-bis(4-hydroxyphenylthio)-propane.

1.3-bis(4-hydroxyphenylthio)-2-hydroxypropane, N,N'-diphenylthiourea, N,N'-di(m-chlorophenyl)thiourea, salicylanilide, 5-chloro-salicylanilide , 2-hydroxy-3-naphthoic acid, 2-hydroxy-1-naphthoic acid, 1-hydroxy-2-naphthoic acid, metal salts of hydroxynaphthoic acid such as zinc, aluminum, calcium, etc., bis-(4-hydroxyphenyl) Acetic acid methyl ester, bis-(4-hydroxyphenyl)acetic acid benzyl ester.

1.3-bis(4-hydroxycumyl)benzene, 1.
4-bis(4-hydroxycumyl)benzene, 2.4'
-diphenolsulfone, 3,3'-diallyl-4,4'-diphenolsulfone, α,α-bis(4-hydroxyphenyl)-α-methyltoluene, antipyrine complex of zinc thiocyanate, tetrabromobisphenol A, Tetrabromobisphenol S, etc.

In the present invention, various conventional binders can be used as appropriate to bind and support the leuco dye, color developer, and auxiliary components on the support.

For example, polyvinyl alcohol, starch and its derivatives,
Cellulose derivatives such as methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, and ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide/acrylic acid ester copolymer, acrylamide/acrylic acid ester/methacrylic acid terpolymer, styrene/ In addition to water-soluble polymers such as maleic anhydride copolymer alkali salt, isobutylene/maleic anhydride copolymer alkali salt, polyacrylamide, sodium alginate, gelatin, and casein, polyvinyl acetate, polyurethane, polyacrylic ester, and Emulsions such as methacrylic acid ester, vinyl chloride/vinyl acetate copolymer, ethylene/vinyl acetate copolymer, stycine/butadiene copolymer, styrene/vinyl acetate copolymer, etc.
Examples include latex such as butadiene/acrylic copolymer.

In addition, in the present invention, in addition to the leuco dye, color developer, and auxiliary components, auxiliary additive components commonly used in this type of heat-sensitive recording material, such as fillers and surfactants, may be used in combination, if necessary. be able to. In this case, fillers include, for example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, talc, and surface-treated inorganic fine powders such as calcium and silica. , urea-formalin resin, styrene/methacrylic acid copolymer, polystyrene resin, and other organic fine powders.

In addition, in the present invention, between the support and the thermosensitive coloring layer,
If necessary, a layer containing a filler, a binder, etc. may be provided as an undercoat layer. In this case, specific examples of the filler and binder include those exemplified in the heat-sensitive coloring layer.

Furthermore, in the heat-sensitive recording material of the present invention, a protective layer can be provided on the heat-sensitive coloring layer for the purpose of improving matching properties with a thermal head etc. and further enhancing recorded image storage stability. case.

The above-mentioned fillers, binders, and surfactants can also be used as components constituting the protective layer.

The heat-sensitive recording material of the present invention can be produced, for example, by applying a coating solution for forming a heat-sensitive coloring layer containing each of the above-mentioned components onto a suitable support such as paper, synthetic paper, or plastic film, and drying the coating solution. .

〔effect〕

The heat-sensitive recording material of the present invention is a heat-sensitive recording material to which a specific thermofusible substance is added, and has high color development sensitivity. In addition, the present invention also has the effect of increasing the number of target substances that can be used as thermofusible substances compared to conventional methods, and also improves compatibility with printing equipment.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples. Note that all parts and percentages shown below are based on weight.

Example 1 A mixture consisting of the following composition was heated, uniformly melted, cooled, solidified, and pulverized to obtain a two-type solid solution (A-1) of thermofusible substances used as Example 1 of the present invention. .

1 part dibenzoylmethane 1 part ρ-toluenesulfonic acid phenyl ester Next, a mixture consisting of the following composition was dispersed so that the volume average particle diameter was about 2 to prepare liquid (A-1).

(A-1) Liquid (A-1) 20 parts 10% polyvinyl alcohol aqueous solution 20 parts water
60 parts of the mixture consisting of the following composition was then added to the above (A-1).
Liquid B-1) and liquid (C-1) were obtained in the same manner as the liquid.

(B-1) Liquid 10% polyvinyl alcohol aqueous solution 20 parts water
60 parts (C-1) Liquid Benzyl P-hydroxybenzoate 20 parts Calcium carbonate 10 parts 10% polyvinyl alcohol aqueous solution 30 parts Water
40 parts of the above liquid (A-1), liquid (B-1), liquid (C-1) and 20%
CD) solution which is a zinc stearate dispersion in a weight ratio of 2:
The mixture was mixed and stirred so that the ratio was 1:3:1, and a heat-sensitive recording coating liquid was applied to a commercially available high-quality paper so that the adhesion amount after drying was approximately 4 gt'rd.Then, the surface was smoothed using a super calender. The heat-sensitive recording material (xi) of the present invention was obtained by adjusting the temperature to 400 to 600 seconds.

Comparative Examples 1 to 3 In place of the solid solution (A-1) in Example 1, the following mixture (a-1) isostatic compound (without heat treatment) of dibenzoylmethane and ρ-toluenesulfonic acid phenyl ester (a
-2) Dibenzoylmethane only (a-3) Liquid (a-1), liquid (a-2), liquid (a-3) in the same manner as in Example 1 except that only ρ-toluenesulfonic acid phenyl ester was used. ) liquid was obtained. Each of these solutions and the above (B-1) solution, (C71) solution, and (D) solution are mixed and stirred in a weight ratio of 3:1:3:1, and the adhesion amount after drying is 4.6g1rd. Heat-sensitive recording materials (R-1) and (R-2) of comparative examples were prepared in the same manner as in Example 1 except that
and (R-3) were obtained.

Example 2 A two-type solid solution (A-2) having the following composition was obtained in the same manner as in the preparation of (A-1) in Example 1.

Benzyl p-benzyloxybenzoate 1 part above (
Example 1 except that A-2) was used in place of (A-1)
A heat-sensitive recording material (X-2) of the present invention was obtained in the same manner as above.

Comparative Example 4 Instead of mixture (a-1) in Comparative Example 1 (a-4)
The heat-sensitive recording material of Comparative Example (R-4 ) was obtained.

Example 3 A three-type solid solution (A-3) having the following composition was obtained in the same manner as in the preparation of (A-1) in Example 1.

Dibenzoylmethane 1 part p-toluenesulfonic acid phenyl ester 1 part Zinc stearate 1 part Next, in place of (A-1) in preparing the (A-1) solution in Example 1, the above (
(A-3) was carried out in the same manner as in Example 1 except that (A-3) was used.
3) A liquid was obtained.

The above (A-3) liquid, the above (B-1) liquid, and (C-1) liquid were mixed and stirred at a weight ratio of 3:1:3 to obtain a thermal recording coating liquid, which was used in Example 1. The heat-sensitive recording material (X-3) of the present invention was obtained by coating and drying in the same manner.

Comparative Example 5 Instead of mixture (a-1) in Comparative Example 1 (a-5)
A mixture of equal amounts of dibenzoylmethane, p-toluenesulfonic acid phenyl ester and zinc stearate (heated “
A heat-sensitive recording material (R-5) of Comparative Example was obtained in the same manner as Comparative Example 1 except that a material (without treatment) was used.

Comparative Example 6 The mixture (a-1) in Comparative Example 1 was used in place of the solid solution (A-1) in Example 1, and the liquid (a-1) was prepared in the same manner as in Comparative Example 1. 1) Liquid, (C-1
A heat-sensitive recording material (R-6) of a comparative example was obtained in the same manner as in Example 1, including the mixing ratio of the liquid (A) and the liquid (CD).

The heat-sensitive recording material obtained in the above manner was tested using a printing experiment device made of electronic components and equipped with a thin film head.
Head power 0.7V/dot, 1 line recording time 10m
5/Q, scanning line density 8 x 7.7 dots/1 m, pulse width 0.3.0.4.0.5.0.6 (mse
c) and measure the print density using Macbeth Densitometer RD-5.
14 (filter Wratten-106),
In addition to conducting a test for color development sensitivity, head matching performance was evaluated by observing the stick sound during printing, the stick appearing in images, and the adhesion of residue to the thermal head. The results are shown in Table-1.

Table-1 ◎No sticking or residue is observed.

O is hardly recognized.

Δ is generated.

Patent applicant Rico Co., Ltd.

Claims (3)

[Claims] (1) A heat-sensitive recording material in which a leuco dye and a color developing substance that causes the leuco dye to develop color when heated are supported on a support, further containing a plurality of thermofusible substances in the form of a mixture. A heat-sensitive recording material characterized by: (2) The heat-sensitive recording material according to claim 1, wherein the thermofusible substance is a substance with a melting point of 60 to 200°C, and the mixture is a solid solution or a eutectic. (3) The heat-sensitive recording material according to claim 1 or 2, wherein at least one of the thermofusible substances forming the mixture is a metal salt of higher fatty acid.