JPS63251279A - Recording material - Google Patents

Abstract

PURPOSE:To form a color image enhanced in color density and also in coloring speed and superior in light-resistance, by a method wherein a thermal recording layer containing a leuco dye shown by a specific formula is laminated on a substrate to prepare a recording material. CONSTITUTION:A thermal recording layer containing a leuco dye shown by a formula I (R<1>, R<2> represent alkyl, cycloalkyl, and aralkyl; R<3>, R<4> represent H, halogen, alkyl, cycloalkyl, and others; R<5> represents alkoxycarbonyl, aryl oxycarbonyl, and others; R<6> represents H, alkyl, aryl, and others; R<7> represents H, halogen, alkyl, alkoxy, hydroxyl, amino, alkylamino, dialkylamino, acylamino, and others; and (n) represents an integer 1-4) is laminated on a substrate to form a recording material.

Description

Detailed Description of the Invention [Field of the Invention] The present invention relates to recording materials such as pressure-sensitive recording materials, heat-sensitive recording materials, and photosensitive recording materials. It relates to a recording material containing a dye.

[Background of the Invention] It has been conventionally known that leuco dyes, also called reduced dyes, exhibit a coloring reaction when in contact with an acidic substance (It coloring agent) and can be easily obtained as a color image. These dyes are widely used as color image forming substances for various recording materials such as heat-sensitive, pressure-sensitive or photosensitive recording materials.

Generally, leuco dyes are contained in the recording layer in a state separated from the above-mentioned acidic substances using a method such as microencapsulation, and then applied with external energy such as pressure and/or heating when used. It is used by destroying the capsule and bringing the two into contact.

Among leuco dyes, compounds that develop a yellow color include, for example, Japanese Patent Publication No. 45-4698 and Japanese Patent Application Laid-open No. 49-1989.
No. 4480, Special Publication No. 50-24646, No. 51-27
There are descriptions in various publications such as No. 169 and No. 53-9127. However, when these dyes were used, high color development was not necessarily obtained. In addition, although an image can be obtained by developing color, the color gradually fades and the image becomes unclear.

[Summary of the Invention] The present invention is characterized by providing a recording material from which yellow images with high color density and excellent light resistance can be obtained. The purpose is to provide recorded materials that have been recorded.

That is, the present invention resides in a recording material containing a novel leuco dye represented by the following general formula [I].

(R7)n [However, in the above general formula [I], R1 and R2
may be the same or different and represent an alkyl group, a cycloalkyl group, or an aralkyl group, and R3
and R4 may be the same or different and represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an aralkyl group, an alkoxy group, or an acylamino group, and R5 represents a hydrogen atom, an alkyl group, an alkoxy group, or an acylamino group. This group and aryloxycarbonyl represent an aryl group, R6 represents a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or an acyl group, and R7 represents a hydrogen atom,
Halogen atom, alkyl group, alkoxy group, hydrosil group, amino group, alkylamino group, dialkylamino group, acylamino group, nitro group, cyano group, carbamoyl group, sulfamoyl group, aryloxycarbonyl group, alkoxycarbonyl group, alkyl represents a sulfonyl group, arylsulfonyl group, alkylsulfonylamino group, arylsulfonylamino group or aryl group,
n represents an integer from 1 to 4; however, when n is 2 to 4, R? may be the same or different), and the above substituents R1 to R7 may be further substituted with other substituents.] [Effects of the Invention] A color image forming substance is added to a recording material. By using the leuco dye (yellow image-forming acid substance) represented by the above general formula [I], the coloring density is high.

Moreover, the coloring speed is fast, and a color image having excellent light resistance can be obtained.

In particular, remarkable effects can be obtained when the above-mentioned leuco dye is used in pressure-sensitive recording materials and heat-sensitive recording materials.

[Detailed Description of the Invention] The leuco dye used in the recording material of the present invention is a compound represented by the following general formula [11].

(R7) n In the general formula [11], the alkyl groups represented by R1 to R7 preferably have 1 to 22 carbon atoms (more preferably 1 to 12 carbon atoms), and these have a linear structure. It may have a branch or be substituted with a substituent such as a /X rogen atom, a cyano group, an alkoxy group, or a hydroxyl group.

The cycloalkyl group represented by R1 to R4 is
For example, a cyclopentyl group, a cycloheptyl group, or a cyclooctyl group can be mentioned.

Examples of the aralkyl group represented by R1 to R4 and R6 include a benzyl group or a phenethyl group, and the phenyl group includes a halogen atom, a lower alkyl group having 1 to 4 carbon atoms, and a lower alkyl group having 1 to 4 carbon atoms. to 4
may be substituted with a lower alkoxy group or a nitro group.

The halogen atom represented by R3, R4 and 1li7 is preferably a chlorine atom or a bromine atom.

Further, the number of carbon atoms in the alkyl moiety of the alkoxy group represented by R3,1 (4 to R7) is preferably 1 to 12, and is substituted with a substituent such as a cyan group, a halogen atom, an alkoxy group, or a hydroxyl group. Good too.

The acylami) group represented by R3, R4 and R7 is
It is represented by the general formula -NC0R8, where R8 represents an alkyl group or an aryl group, and R9 represents a hydrogen atom, an alkyl group or an aryl group.

The above alkyl group has the same meaning as above, and the aryl group is preferably a phenyl group or a naphthyl group, a halogen atom, or a lower alkyl group (having 1 to 4 carbon atoms).
, a lower alkoxy group (having 1 to 4 carbon atoms), a nitro group, or the like.

The aryl group represented by R5 and R7 has the same meaning as the aryl group explained above.

The alkoxy moiety of the alkoxycarbonyl group represented by R5 and R7 has the same meaning as the alkoxy group described above.

The acyl group represented by R5 and R also has the general formula -(::
Qllilo (llilo is synonymous with R8 above)
It is expressed as

The alkyl moiety of the alkylamine group, dialkylamino group, alkylsulfonyl group and alkylsulfonylamino group represented by R1 has the same meaning as the alkyl group explained above.

The aryl moiety of the aryloxycarbonyl group represented by R5 and R1, the arylsulfonyl group and the arylsulfonylamine group represented by R7 has the same meaning as the aryl group explained above.

The carbamoyl group represented by R7 has the general formula 〇〇NRI
IR12 (R1+ and 11112 are each the above R
It is a group represented by (synonymous with 9).

In addition, the sulfamoyl group has the general formula -S Ot N11
i 13R14 (ill 13 and R have the same meanings as R9 above).

Next, typical examples of the leuco dye represented by the above general formula [I] that can be used in the recording material of the present invention are shown below, but the invention is not limited thereto.

The following margins are below: 7J millimeters (l 1) Below: Margins (l 3) (l 4) Below: Margins [Synthesis example] The leuco dye (1) used in the present invention can be synthesized, for example, by the method shown in the following formula. .

[il [iil [1ii1 [iV] [V] Leuco dye (1) Space below Next, a method for synthesizing leuco dye (1) and other typical leuco dyes will be described according to the above synthesis formula.

[Synthesis Example 1] Synthesis of leuco dye (1) Synthesis of compound (i) Fluorescein 221g, n-butyl bromide 453
g, 455 g of potassium carbonate, and 500 ml of N,N-dimethylacetamide were placed in a Mitsuro flask and heated at 90°C.
After 4 hours of reaction, the mixture was poured into water 31, extracted with 500 ml of ethyl #acid, and then evaporated under reduced pressure.

Add 700ml of ethyl alcohol to the resulting oil! ;160ml of aqueous solution containing L and 80g of sodium hydroxide! ; Add L and heat and stir for 30 minutes, then add 2M water and Jgf.
The precipitated crystals were separated by filtration.
Next, this was washed with acetonitrile and then dried to obtain compound (i) with a melting point of 156-157°C (yield: 245 g).

The combination of (i) 245 g of the compound (1) above, benzene Ro.

ml and 48 mft of thionyl chloride were refluxed for 2 hours. After concentration under reduced pressure, 500 mJL of acetonitrile was added, and 250 mM of ammonia water was added dropwise under water cooling. After stirring at room temperature for 1 hour, add 500ml of water and ice and add salt @ 25ml.
Added 0 mJl. The precipitated crystals were filtered, washed with acetonitrile, and then dried to obtain compound (ii) with a melting point of 152 to 153°C (yield: 220 g).

Preparation of the compound (iii) Dissolve 178 g of the compound (ii) above in 1 ml of toluene and 1 liter of methyl alcohol, add 160 mfL of a 28% sodium methylate solution in methyl alcohol at 20°C or below, and then add 20.5 mJ 1 of bromine. was added below 15°C. After stirring at room temperature for 30 minutes, it was concentrated under reduced pressure and subjected to column chromatography (developing solvent: n-hexane/ethyl acetate = 87
Purify with 1).

Compound (iii) with a melting point of 90-92°C was obtained (yield x
3zg).

(130 g of compound (iii) of compound (ii), methyl cellosolve 2
．． Aqueous solution 2 containing 0 fL and 125 g of potassium hydroxide
00mJIL was placed in a flask and stirred at an external temperature of 120°C for 2 hours. After concentration under reduced pressure, 1 liter of water, 700 ml of ethyl acetate
M! ; L was added in order, extracted, and concentrated under reduced pressure. Furthermore, 700 ml of methyl alcohol was added, and after stirring at room temperature for 2 hours, the precipitated crystals were separated by filtration.
The compound (ii) was obtained (yield: aOg).

Synthesis of compound (V) 163 g of ethylamine hydrochloride and 7 acetonitrile
240mf of sulfuryl chloride in a solution of 00mJ1
1 and antimony pentachloride (5 ml) were added, and the mixture was heated and stirred for 5 hours. After completion of the reaction, it was concentrated under reduced pressure, and then distilled (
93-b 177 g of ethylaminosulfonyl chloride was obtained.

2 g of ethylaminosulfonyl chloride obtained above, 5 g of the compound (ii) above and 20 m of acetotrile
1.1 mJl of pyridine was added dropwise into the mixed solution.

After stirring at room temperature for 2 hours, the mixture was poured onto wood and the precipitated crystals were separated to obtain compound (V) with a melting point of 60-65°C (yield: 6 g).

Synthesis of leuco dye (1) 6 g of the compound (V) above, 20 mJl of ethyl acetate and 15 g of manganese dioxide were placed in a flask and heated and stirred for 2 hours. After the reaction was completed, it was filtered, concentrated under reduced pressure, and then recrystallized from acetonitrile. A leuco dye (1) having a melting point of 147 to 149° C. was obtained (yield: 3 g).

[Synthesis Example 2] Synthesis of Leuco Dye (5) 4.2 g of chlorosulfonyl isocyaner was placed in 9 ml of dichloromethane, and 2.2 g of t-butanol was added dropwise at 25° C. or below, followed by stirring for 30 minutes. Thereafter, compound 10 of (i-ma) obtained according to the above synthesis method 1 was added to this solution.
．． A mixture of 5g, N,N-dimethylacetamide, 9mM, and pyridine 7.2ml was added dropwise at below 15°C and stirred at room temperature for 30 minutes. , melting point 139-141℃
The compound was obtained (yield: 7 g).

7 g of the above compound, 50 mJL of ethyl acetate, and 25 g of manganese dioxide were placed in a flask, and the mixture was heated and stirred for 2 hours.
After the reaction was completed, it was filtered, subjected to eliiAt under reduced pressure, and then purified by column chromatography (developing solvent: n-hexane/ethyl acetate = 3/l) to obtain a leuco dye (5) with a melting point of 167-169°C. (Yield: 4g).

In addition, other leuco dyes other than the synthesis examples described above can also be synthesized in the same manner as above.

Margin below The recording material of the present invention is one in which the leuco dye represented by the general formula [I] as described above is contained in the recording layer, either alone or in an appropriate mixture. It is also possible to use a mixture of the leuco dye according to the present invention and one or more other known leuco dyes having the same or different color hues, and by doing so, various color images can be obtained. Examples of known leuco dyes include the aforementioned triarylmethane compounds, diphenylmethane compounds, quinanthene compounds, thiazine compounds, spiro compounds, or mixtures thereof.

In the recording material of the present invention, the leuco dye and the acidic color developer described below are separated, and the two are brought into contact with each other during image formation. The leuco dye and the color developer are separated by a method such as storing the leuco dye and the color developer together in the recording layer, or including the leuco dye and the color developer in separate layers. The two are used by bringing them into contact by applying pressure and/or heating. Alternatively, the leuco dye and the color developer may be contained in separate materials (for example, a material containing the leuco dye and a material containing the color developer) and then separated, and then combined and processed during image formation. The two are used by bringing them into contact by applying pressure and/or heat.

In addition, in this case.

The acidic color developer may be contained in a microcapsule separate from the microcapsule containing the leuco dye and may be present in the same layer or in a separate layer.

In particular, when forming an image using a pressure-sensitive recording material or a photosensitive recording material among the recording materials of the present invention, the above-mentioned leuco dye is microencapsulated and contained in the recording layer, while an acidic color developer is It is preferable to use an embodiment in which the colorant is contained in another material (for example, a color developer sheet or an image-receiving material).

By adopting the above usage mode, the sensitivity and sharpness of the color image obtained can be improved.

In the above color development reaction, it is preferable to bring the leuco dye and the color developer into contact under heating conditions.Heating can significantly accelerate the above color development reaction.

The heating temperature is generally 50°C to 200°C, preferably 50°C to 150°C. The heating time is generally 1
The time period is from 1 second to 1 minute, preferably from 1 second to 10 seconds.

Examples of the acidic color developer mentioned above include acidic clay color developer (
clay), phenol-formaldehyde resin (e.g.
p-phenylphenol-formaldehyde resin),
Metal salts of salicylic acids (e.g., zinc 3,5-di-α-methylbenzylsalicylate), phenol-salicylic acid-formaldehyde resin (e.g., p-octylphenol-
Zinc salicylate-formaldehyde resin), zinc rhodan, zinc xanthate, and the like.

Among these acidic color developers, metal salts of salicylic acids are preferred as color developers that can be used in the present invention, and zinc salicylate color developers are particularly preferred; that is, according to research by the present inventors, It has been revealed that the coloring reaction of leuco dyes proceeds rapidly and efficiently in the presence of a zinc salicylate-based color developer. Details of metal salts of salicylic acids can be found in, for example, Japanese Patent Publication No. 1327/1983. Regarding oil-soluble zinc salts of salicylic acid, US Pat. No. 3,864,146 and US Pat. No. 4,046
There are descriptions in each specification of No. 941.

The acidic color developer mentioned above has a 2
It is preferably used in a range of 50 to 1000% by weight, and more preferably in a range of 100 to 1000% by weight.

The leuco dye according to the present invention can be applied to any recording material such as a pressure-sensitive recording material, a heat-sensitive recording material, or a photosensitive recording material, but can be particularly suitably used for a pressure-sensitive recording material or a heat-sensitive recording material. .

Among recording materials, the present invention will be explained in more detail by taking pressure-sensitive recording materials and heat-sensitive recording materials as examples.

A pressure-sensitive recording material (sheet) generally comprises a color former-containing sheet (hereinafter referred to as a color former sheet) containing a color former containing at least one of the leuco dyes according to the present invention, and a color developer described above. A color developer sheet is composed of a set of materials (sheets) including a color developer-containing sheet (hereinafter referred to as a color developer sheet), and includes a support and a layer containing a color developer provided thereon. , and the developer sheet is a support,
Each layer is composed of a layer containing a color developer provided thereon.

A layer containing a color former can be formed on a support as follows.

The layer containing the coloring agent is a layer in which the coloring agent is contained and supported in a dispersed state by Pai Goo.

The coloring agent containing the leuco dye is preferably in the form of microcapsules.

Microcapsules can be formed, for example, by the following method.

After the above-mentioned color former is dissolved or dispersed in a suitable organic solvent, this solution or dispersion (oil-based liquid) is emulsified and dispersed in an aqueous medium.

If an organic solvent with a low boiling point is used, there will be evaporation loss during storage, so it is preferable that the organic solvent has a boiling point of 180° C. or higher.

Phosphate esters, phthalate esters, other carboxylic acid esters, fatty acid amides, alkylated biphenyls, alkylated terphenyls, chlorinated paraffins, alkylated naphthalenes, diarylethanes, and the like are used.

Specific examples include tricresyl phosphate, trioctyl phosphate, octyl difecol phosphate, tricyclohexyl phosphate, dibutyl phthalate, dioctyl phthalate,
Dilauryl phthalate, dicyclohexyl phthalate, butyl oleate, diethylene glycol dibenzoate,
Dioctyl sebacate, dibutyl sebacate, dioctyl adipate, trioctyl trimellitate, acetyltriethyl citrate, octyl maleate, dibutyl maleate, isopropylbiphenyl, inamyl biphenyl, chlorinated paraffin, diisopropylnaphthalene,
1. Examples include lo-ditolylethane, 2,4-di-tert-ami)Ii7xnol, N,N-dibutyl-2-butoxy-5-tert-octylaniline.

In addition to these, vinyl compounds can also be used as suitable organic solvents.

The leuco dye according to the present invention is preferably used in an amount of 2 to 20% by weight based on the organic solvent.

Next, a capsule wall made of a polymer material is formed around the emulsified and dispersed oil droplets.

There are no particular restrictions on the polymeric material that forms the capsule wall; examples thereof include polyurethane, polyurea, polyamide, polyester, urea/formaldehyde resin, melamine resin, polystyrene, styrene/methacrylate copolymer, and styrene/acrylate copolymer. Mention may be made of polymers and mixed systems thereof.

The method for forming microcapsules is not particularly limited, and any known method can be used; however, in the present invention, interfacial polymerization and internal polymerization are preferred.

For example, when polyurea polyurethane is used as the capsule wall material, the polyisocyanate and the second material that reacts with it to form the capsule wall (e.g., polyol, polyamine) are mixed into the aqueous medium or oily liquid to be encapsulated.

By emulsifying and dispersing these in water and heating them first,
A polymer formation reaction occurs at the oil droplet interface and a microcapsule wall is formed.

Furthermore, when forming microcapsules, a water-soluble polymer compound can be used as a protective colloid. Examples of the water-soluble polymer compound include water-soluble anionic polymer compounds, nonionic polymer compounds, and amphoteric polymer compounds.

The anionic polymer compound may be a natural substance or a synthetic substance, and includes, for example, those having carboxyl groups, sulfonic acid groups, etc. Specific examples include anionic natural polymer compounds such as gum arabic and alginic acid; carboxymethyl cellulose, phthalated gelatin, sulfated starch,
Semi-synthetic polymer compounds such as sulfated cellulose and ligninsulfonic acid; and maleic anhydride (including hydrolyzed) copolymers, (meth)acrylic acid polymers and copolymers, and vinylbenzenesulfonic acid. Synthetic polymer compounds include polymers, copolymers, and carboxy-modified polyvinyl alcohol. Specific examples of nonionic polymer compounds include polyvinyl alcohol and hydroxyethyl cellulose.

Specific examples of amphoteric polymer compounds including methylcellulose include gelatin.

These water-soluble polymer compounds are contained in an amount of 0.01 to 10% by weight.
It is used as an aqueous solution.

Examples of binders used in layers containing color formers include polyvinyl alcohol and methylcellulose.

Mention may be made of carboxymethylcellulose, hydroxypropylcellulose, gum arabic, gelatin, polyvinylpyrrolidone, casein, styrene-butadiene latex, acrylonitrile-butadiene latex, polyvinyl acetate, polyacrylic acid ester and ethylene-vinyl acetate copolymer, These compounds are used in the form of various emulsions.

The amount of binder used is in the range of 0.5 to 5 g/rr1' of solid content.

The layer containing the color former is prepared by mixing the liquid containing the microcapsules and the binder solution to prepare a coating liquid, and then applying this coating liquid by a conventional coating method such as bar coating, blade coating, or air knife coating. It can be formed by applying it to a support by a coating method such as gravure coating, roll coating, spray coating, dip coating, etc., and drying it.

The layer containing the coloring agent usually has a solid content of 2.5 to 25 g/rr?
It is established within the range of .

The support used in the present invention is usually paper.
Neutral paper (as described in JP-A-55-14281) is preferred from the viewpoint of long-term storage stability, and these may be appropriately surface-treated.

On the other hand, for the layer containing the m colorant, a coating solution was prepared by mixing the Pai Goo used above with the emulsion solution containing the above color developer prepared in advance, and then this coating solution was mixed in the same manner as above. It can be formed by coating it on a support using a solvent and drying it. Note that paper is also suitably used as the support in the same manner as above.

A pressure-sensitive recording material (sheet) containing a leuco dye according to the present invention can be obtained by combining (bonding) the coloring agent sheet obtained as described above and the coloring agent sheet No. 11.

The above-mentioned pressure-sensitive recording material is an example of an embodiment, and in addition to the above, 5, for example, a color forming agent and a color developing agent are housed in separate microcapsules in the same sheet (same R). As mentioned above, the color forming agent and the color developer may be present in separate layers, and the pressure-sensitive recording sheet may have a multilayer structure.

The recording method using the pressure-sensitive recording material of the present invention is carried out by applying external pressure to the recording paper, for example, from a pencil or a typewriter. That is, the microcapsules present in the area where the pressure is applied are destroyed, the color forming agent inside is released, and this contacts the adjacent color developing agent to generate color.

Next, the heat-sensitive recording material will be explained.

The structure of the heat-sensitive recording material can basically be the same as the structure of the pressure-sensitive recording material described previously. That is, the heat-sensitive recording material is composed of a support and a heat-sensitive recording layer provided on the support. The recording layer contains a coloring agent containing a leuco dye according to the present invention. However, from the viewpoint of reducing the thermal energy required for thermoresponsive 5 color development, it is preferable that the m coloring agent also exists in the same layer. In this case, it is sufficient that both are isolated within the layer. However, it is further preferable that the coloring agent is microencapsulated using the above method and contained in the recording layer.

From this point of view, the microcapsule wall material is preferably a polymeric substance that is impermeable at room temperature and becomes permeable when heated, and in particular, one with a glass transition temperature of 60 to 200°C is preferable. Of the above wall materials, polyurea or polyurethane is particularly preferred.

Heat-sensitive recording on the heat-sensitive recording material of the present invention can be performed, for example, as follows.

First, the recording paper is placed in contact with a heating body (print head) such as a hot stylus or a thermal head. At the same time, the recording paper is scanned in one direction while in contact with the recording paper.Meanwhile, by moving the recording paper in a direction perpendicular to the scanning direction of the heating element, two Prints or images can be formed dimensionally.

As described above, typical recording materials of the present invention have been described. However, in addition to the above, the recording materials of the present invention include, for example, an electric heat-sensitive recording sheet, an ultrasonic recording sheet, an electron beam recording sheet, or an electrostatic recording sheet. This also includes recording sheets.

Note that the above-mentioned photosensitive recording material includes a photosensitive recording sheet made of a photosensitive resin (for example, a photoresist material, P
In addition to photosensitive recording materials (Japanese Patent Laid-Open Publication No. 61-69028), which have a photosensitive layer on a support, which includes silver halide, a reducing agent, and a polymerizable compound, are also included. In this case, the recording material is used in one manner: the leuco dye according to the present invention is contained in microcapsules together with a polymerizable compound and contained in the recording layer, while the color developer is contained in the image-receiving material and subjected to exposure and development processing. It is preferable to use both of them in a superimposed manner during subsequent image formation.

The present invention will be explained in more detail by the following examples. However, the present invention is not limited to this.
In the examples, 1 part 1 means 1 part by weight unless otherwise specified.

Below, remaining white [Example 1] [Preparation of pressure-sensitive recording sheet T&] A pressure-sensitive recording sheet was created as follows.

Preparation of color former sheet Partial sodium salt of polyvinylbenzenesulfonic acid (trade name: VERSA, TL500. Average molecular weight: 50
0°000, manufactured by National Starch) at about 80°C.
The mixture was added to 95 parts of hot water with stirring and dissolved. The sodium salt was dissolved in about 30 minutes and then cooled. The pH of the aqueous solution was 2 to 3, and a 20% by weight aqueous sodium hydroxide solution was added thereto to adjust the pH to 4.0.

On the other hand, the following leuco dye (1) [color former] was added to 3.5
100 parts of diisopropylnaphthalene dissolved in 5% of the sodium salt of the polyvinylbenzenesulfonic acid
Emulsified and dispersed in 100 parts of aqueous solution, average oil droplet size 4.5
An emulsion of gm was obtained.

Leuco dye (1) 11 parts of human aqueous solution and 30 parts of water were heated to 60°C and stirred.
After 0 minutes, a transparent mixed aqueous solution (initial condensate solution) of melamine, formaldehyde, and melamine-formaldehyde initial condensate was obtained. The pH of this mixed aqueous solution was 6-8.

Next, the initial condensate solution obtained by the above method was added to and mixed with the above emulsion, and the pH was adjusted to 6.0 with a 3.6% by weight phosphoric acid solution while stirring, and the liquid temperature was adjusted to 65%. The microcapsule dispersion was stirred for 6 hours.

Furthermore, this capsule dispersion was cooled to room temperature and 20% by weight
The pH was adjusted to 9.0 with sodium hydroxide.

To this capsule dispersion, 200 parts of a 10% by weight polyvinyl alcohol (trade name, PVA-117, manufactured by Kuraray ■) aqueous solution and 50 parts of starch particles were added, and water was added to prepare a coating liquid with a solid content concentration of 20%. Then, this coating liquid was applied to a base paper of 50 g/g using an air knife coater so that the solid content was 5 g/rn', and dried to prepare a coloring agent sheet.

Preparation of color developer sheet 3. Zinc 5-bis-α-methylbenzylsalicylate 10
1-isopropylphecho-2-phenylethane 2 parts
0 parts and heated and dissolved at 90°C. This was added to 50 parts of a 2% by weight polyvinyl alcohol (trade name: PVA-117, manufactured by Kuraray ■) aqueous solution, and further 0.1 part of a 10% aqueous solution of dodecylbenzenesulfonic acid triethanolamine salt [surfactant]. In addition, an emulsion having an average particle size of 31 parts was prepared using a homogenizer.

Next, 80 parts of calcium carbonate, 20 parts of zinc oxide, 1 part of sodium hexametaphosphate, and 200 parts of water were dispersed using a Kechiemyl to prepare a dispersion. After mixing the above emulsion, 100fi of a 10% by weight aqueous solution of polyvinyl alcohol (product name: PVA-117, manufactured by Kuraray ■) was added as a binder, and carboxy-modified SBR latex (product name: SN-307, Sumitomo) was added as a solid content. 10 parts (manufactured by Naugatax ■) was added to make the solid content concentration 20.
% of water to prepare a coating liquid (A).

Separately, 15 parts of zinc 3,5-bis-α-methylbenzylsalicylate, 20 parts of Jilton clay, and 60 parts of calcium carbonate.
A dispersion liquid having an average particle size of 31 parts m was prepared using a sand glider using 20 parts of zinc oxide, 1 part of sodium hexametaphosphate, and 200 parts of water.

First, 16 parts of a 10% by weight polyvinyl alcohol (trade name: HPVA-103, manufactured by Kuraray ■) aqueous solution was added to the obtained dispersion, and then 16 parts of a 10% by weight polyvinyl alcohol (trade name: PVA-117, manufactured by Kuraray ■) was added. ) aqueous solution 1
00 parts and solid content of carboxy-modified SBR latex (trade name: 5N-307, manufactured by Sumitomo Nogatax ■)
A coating liquid (B) was prepared by adding 10 parts of water and adding water so that the solid content concentration was 20%.

Coating liquid (A) and coating liquid (B) obtained in the following were mixed with A/B concentration 50150 in terms of color developer, and coated on base paper of 50 g/rrr' at a solid content of 5.0 g/rrf. A developer sheet was prepared by coating with an air knife coater and drying as shown.

A pressure-sensitive recording sheet (1) was prepared by combining the color former sheet and developer sheet obtained as described above.

[Examples 2 to 3] In Example 1, the leuco dye (
Instead of 1), the following leuco dyes (4) and (5) can be used.
), except that pressure-sensitive recording sheets (■) and (m) corresponding to the present invention were prepared by operating in the same manner as in Example 1.

Leuco color (4) Leuco dye (5) [Comparative Examples 1-2] In Example 1, the leuco dye (
The corresponding pressure-sensitive recording sheets (■) and (V
)It was created.

Leuco dye (a) Leuco dye (b) [Evaluation of pressure-sensitive recording sheets] Each pressure-sensitive recording sheet (I) to (
Pressure was applied to V), and the density of each yellow image obtained was measured using a reflection densitometer.

Next, each of the yellow images obtained above was subjected to a photofading test as described below to evaluate light resistance.

The photofading test was conducted by irradiating the resulting color image with 80,000 lux canon light for 3 hours, and then measuring the remaining density in the same manner as above. Note that the evaluation was expressed as the residual rate (%) of the color image after the photofading test.

Table 1 summarizes the measurement results north of the area.

Table 1 Pressure Sensitive Recording Leuco Coloring Lightfast Recording Sheet Dye Concentration (%) Example 1 (I) (1) 0.93 96 Same
2 (II) (4) 1.05
933 (III) (5) 1.15
95 Comparative Example 1 (IV) (a) 0
．． 71 822 (V) (b)
0.52 65% As is clear from the results in Table 1, the pressure-sensitive recording sheet CI containing the leuco dye according to the present invention
m) are pressure-sensitive recording sheets containing known leuco dyes (
(2) Compared to v and V), it showed a high color density, a fast color development rate, and excellent light resistance.

Claims (1)

[Claims] 1. A recording material characterized by containing a leuco dye represented by the following general formula [I]. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] [However, in the above general formula [I], R^1 and R^2 may be the same or different, and may be an alkyl group, a cycloalkyl group, or represents an aralkyl group, R^3 and R^4 may be the same or different from each other, and represent a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an aralkyl group, an alkoxy group, or an acylamino group; 5 is a hydrogen atom, an alkyl group,
It represents an alkoxycarbonyl group, an aryloxycarbonyl group, or an aryl group, R^6 represents a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or an acyl group, and R^7 represents a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group. , hydroxyl group, amino group, alkylamino group, dialkylamino group, acylamino group, nitro group, cyano group, carbamoyl group, sulfamoyl group, aryloxycarbonyl group, alkoxycarbonyl group, alkylsulfonyl group, arylsulfonyl group, alkylsulfonylamino group group, an arylsulfonylamino group or an aryl group, n represents an integer from 1 to 4 (however, when n is 2 to 4, each of R^7 may be the same or different), The above substituents R^1 to R^7 may be further substituted with other substituents.] 2. A patent characterized in that the recording material is a pressure-sensitive recording material or a heat-sensitive recording material. Recording material according to claim 1. 3. Claim 2, characterized in that the leuco dye is contained in microcapsules.
Recording materials listed in section. 4. The recording material according to claim 1, wherein the leuco dye is a compound that exhibits a color-forming reaction upon contact with an acidic color developer. 5. The recording material according to claim 1, wherein the leuco dye is contained in an amount of 2 to 20% by weight based on the organic solvent.