JPH047717B2 - - Google Patents

Description

[Detailed description of the invention] <Field of application of the invention> The present invention relates to recording materials.

The recording material according to the present invention utilizes a color-forming reaction between an electron-donating colorless dye and an electron-accepting compound, and particularly relates to a recording material containing a novel electron-accepting compound.

The electron-accepting compound according to the present invention is an extremely useful compound particularly as an electron-accepting compound for pressure-sensitive recording materials and heat-sensitive recording materials. It is a compound that can also be applied to electron/ray recording sheets, electrostatic recording sheets, photosensitive pressure-sensitive recording sheets, etc.

<Prior art> The use of various phenol compounds as electron-accepting compounds for pressure-sensitive recording materials or heat-sensitive recording materials is disclosed in Japanese Patent Publication No. 40-9309, Japanese Patent Publication No. 45-14039,
Although disclosed in Japanese Patent Publication No. 51-29830, etc., these phenol compounds have the disadvantage that the coloring density is not sufficient when used in combination with an electron-donating colorless dye.

It has also been proposed to use alkyl esters of hydroxybenzoic acid as electron-accepting substances, but when used in heat-sensitive recording materials, (a) the recording material has insufficient moisture and heat resistance, and (b) fogging occurs. There were many problems that needed to be improved, such as (c) the density of the image area decreased over time after recording, and (d) the occurrence of white powdery substances concentrated on the surface, so-called powder blowing.

The present inventors have been developing hydroxy-substituted benzoic acid esters, and have focused on improving the ester moiety, and have achieved effects that are comparable to those of the invention that is already pending. This led to the present invention.

<Objective of the Invention> Therefore, an object of the present invention is to provide a recording material which has sufficient color density when used in combination with an electron-donating colorless dye and has improved storage stability both raw and over time.

<Structure of the Invention> The object of the present invention has been achieved by a recording material characterized in that it is a compound represented by the following general formula () as an electron-accepting compound that causes an electron-donating colorless dye to develop color.

[In the above formula, R ₁ and R ₂ represent a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group, an alkyl group, or an alkenyl group, and R ₃ represents an epoxy ring,
It represents a residue containing a tetrahydrofuran ring or a furan ring, and R ₁ and R ₂ may be combined to form a 5- or 6-membered ring. ] When using the electron-accepting compound according to the present invention as an electron-accepting compound for heat-sensitive recording materials, the temperature is 50°C.
It is preferable to have a melting point of 70℃ or higher, especially 70℃~
Those having a melting point of 150°C are preferred.

The characteristics of the electron-accepting compound according to the present invention include the following.

() In combination with an electron-donating colorless dye,
Gives a high-density color image.

() Significantly high oil solubility.

() Stable without sublimation.

() It is easy to synthesize and can be obtained in high yield and purity. The raw materials are also cheap.

The compounds of the present invention can be produced by a reaction that forms an ester bond between a corresponding carboxylic acid, carboxylic acid halide, carboxylic acid metal salt, carboxylic acid lower alkyl ester, etc. and a halide, alcohol, or ester having an oxygen-containing heterocycle. Can be easily synthesized.

In the present invention, the oxygen-containing heterocycle is selected from, for example, those having a 3- to 6-membered structure as described below.

It includes saturated or unsaturated heterocycles such as an epoxy ring, a furan ring, a dioxane ring, a hydrofuran ring, a hydropyrone ring, a pyran ring, a hydropyran ring, a dioxolane ring, a cyclic acetal ring, and a xanthene ring. Ester bonds are hydroxy groups directly connected to these heterocycles, alkylene, alkenylene,
Needless to say, it is formed using a hydroxy group via a group such as oxaalkylene. Particularly preferred is the case where a group such as methylene, ethylene, or oxaethylene is used.

Next, specific examples of the electron-accepting compound of the present invention will be shown, but the present invention is not limited thereto.

(1) 2,4-dihydroxy-6-methylbenzoic acid glycidyl ester (2) 2,4-dihydroxy-6-propylbenzoic acid tetrahydrofurfuryl ester (3) 2,4-dihydroxy-6-methoxybenzoic acid tetrahydrofurfuryl ester Furyl ester (4) 2,4-dihydroxy-6-ethylbenzoic acid tetrahydrofurfuryl ester (5) 2,4-dihydroxy-6-methylbenzoic acid tetrahydrofurfuryl ester (6) 2,4-dihydroxybenzoic acid methyltetrahydro Furfuryl ester (7) 2,4-dihydroxybenzoic acid tetrahydrofurfuryl ester (8) p-oxybenzoic acid furfuryl ester (9) 2,4-dihydroxy-5-chlorobenzoic acid furfuryl ester (10) p-oxy Benzoic acid tetrahydrofurfuryl ester (11) 2,4,6-trihydroxybenzoic acid tetrahydrofurfuryl ester (12) 2,4,6-trihydroxybenzoic acid furyl ester (13) 2,4-dihydroxy-6-benzyl Benzoic acid tetrahydrofurfuryl ester (14) 2,4,6-trihydroxy-3-chlorobenzoic acid tetrahydrofurfuryl ester (15) 2,4-dihydroxy-6-phenylbenzoic acid tetrahydrofurfuryl ester (16) 2, 4-dihydroxy-6-ethoxybenzoic acid furfuryl ester (17) 2,4-dihydroxy-6-methylbenzoic acid furfuryl ester (18) 2,4-dihydroxy-6-pentylbenzoic acid furfuryl ester, and the like.

These may be used alone or in combination, or mixed with other substances such as bisphenol A, benzyl 4-hydroxybenzoate, phenethyl 2,4-dihydroxybenzoate, and 1,1-bis-4-hydroxyphenylcyclohexane. used. When mixing, the ratio is determined in consideration of solubility, temperature at which color development starts, solvent resistance, etc. In particular, zinc salts of salicylic acid derivatives and the like are co-dissolved to provide favorable light resistance and finger squeezing resistance.

As the electron-donating colorless dye used in the present invention, triarylmethane compounds, diphenylmethane compounds, xanthene compounds, thiazine compounds, spiropyran compounds, etc. are used.

To illustrate some of these, triarylmethane compounds include 3,3-bis(p-dimethylaminophenyl)-6-dimethylaminophthalide;
3,3-bis(p-dimethylaminophenyl)phthalide, 3-(p-dimethylaminophenyl)-3
-(1,3-dimethylindol-3-yl)phthalide, 3-(p-dimethylaminophenyl)-3
-(2-methylidol-3-yl)phthalide, etc. Diphenylmethane compounds include:
There are 4,4'-bis-dimethylaminobenzhydrin benzyl ether, N-halophenyl-leucoauramine, N-2,4,5-trichlorophenylleucoauramine, and xanthene compounds include rhodamine-B. -anilinolactam, rhodamine (p-nitroanilino)lactam, rhodamine B (p-chloroanino)lactam, 2-dibenzylamino-6-diethylaminofluorane, 2-anilino-6-diethylaminofluorane, 2-anilino-3- Methyl-6-diethylaminofluorane, 2-anilino-3-methyl-
6-N-cyclohexyl-N-methylaminofluorane, 2-anilino-3-methyl-6-N-ethyl-N-isoamylaminofluorane, 2-o
-chloroanilino-6-diethylaminofluorane, 2-(3,4-dichloroanilino)-6-diethylaminofluorane, 2-octylamino-6
-diethylaminofluorane, 2-anilino-3
-Methyl-6-diphenylaminofluorane, 2
-anilino-3-methyl-5-chloro-6-diethylaminofluoran, 2-anilino-3-methyl-6-diethylamino-7-methylfluoran, 2-butylamino-3-chloro-6-diethylaminofluoran, 2-ethoxyethylamino-3-chloro-6-diethylaminofluorane,
2-anilino-3-chloro-6-diethylaminofluorane, 2-anilino-3-methyl-6-dioctylaminofluorane, 2-dimethylaminocarbonylethylamino-6-diethylaminofluorane, 2-o-chloroanilino-6 -dibutylaminofluoran, 2-anilino-3-pentadecyl-6-diethylaminofluoran, 2-anilino-3-ethyl-6-dibutylaminofluoran, 2-anilino-3-ethyl-6-N-ethyl-N -isoamylaminofluorane, 2-anilino-3-methyl-6-N-ethyl-N-γ-methoxypropylaminofluorane, 2-p-chloroanilino-3-phenyl-6-diethylaminofluorane, 2-phenyl- Thiazine compounds include 6-diethylaminofluorane, etc.
There are benzoyl leucomethylene blue, p-nitrobenzyl leucomethylene blue, etc., and spiro compounds include 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran,
3,3'-dichloro-spirodinaphthopyran, 3-
Benzylspirodinaphthopyran, 3-methylnaphtho-(3-methoxy-benzo)-spiropyran, 3
-propyl-spiro-dibenzopyran and the like.
These may be used alone or in combination.

Next, a specific method for manufacturing the recording material according to the present invention will be described.

The pressure-sensitive copying paper according to the present invention is disclosed in U.S. Patent No. 2505470.
No. 2505471, No. 2505489, No. 2548366,
It can take various forms as described in prior patents such as No. 2712507, No. 2730456, No. 2730457, and No. 3418250. Most commonly, it will consist of at least one pair of sheets separately containing an electron-donating colorless dye and an electron-accepting compound according to the invention. That is, electron-donating colorless dyes, alone or in combination, are dissolved in a solvent (synthetic oil such as alkylated naphthalene, alkylated diphenyl, alkylated diphenylmethane, alkylated diarylethane, chlorinated paraffin, etc.), and this is dispersed in a binder. Alternatively, after containing it in microcapsules, it can be applied to a support to form a coloring agent sheet, and an electron-accepting compound alone or in a mixture or together with other electron-accepting compounds, styrene-butadiene latex, A developer sheet is obtained by dispersing it in a binder such as polyvinyl alcohol and applying it to a support such as paper, plastic sheet, resin coated paper, etc.

The amounts of the electron-donating colorless dye and the electron-accepting compound to be used depend on the desired coating thickness, the form of the pressure-sensitive copying paper, the capsule manufacturing method, and other conditions, and may be appropriately selected depending on the conditions.

U.S. patent for method of manufacturing capsules
A method using coacervation of a hydrophilic colloid sol described in No. 2800457 and No. 2800458,
British Patent No. 867797, British Patent No. 950443, British Patent No. 989264, British Patent No.
Examples include the interfacial polymerization method described in No. 1091076.

The heat-sensitive recording material is prepared by adding an electron-donating colorless dye, an electron-accepting compound according to the present invention, and, if necessary, a thermofusible substance to a liquid in which a binder is dissolved or dispersed, individually or in combination, and sufficiently finely ground. After mixing, oil-absorbing pigments such as kaolin, calcined kaolin, talc, diatomaceous earth, calcium carbonate, aluminum hydroxide, acid clay, barium sulfate, urea-formalin filler, and cellulose filler are added to form a coating solution. If necessary, a paraffin wax emulsion, a latex binder, a sensitivity improver, a metal soap, an antioxidant, an ultraviolet absorber, an image storage improver, etc. can be added.

The coating solution is applied to a support such as neutral paper, high-quality paper, or plastic film and dried. When preparing a coating liquid, all the components may be mixed and pulverized at the same time from the beginning, or they may be combined in appropriate combinations, pulverized and dispersed separately, and then mixed.

The amounts of each component constituting the heat-sensitive recording material are 1 to 2 parts by weight of an electron-donating colorless dye, 1 part by weight of an electron-accepting compound, and 1 to 2 parts by weight of an electron-donating colorless dye.
~6 parts by weight, 0 to 30 parts by weight of thermofusible substance, 0 pigments
It generally consists of ~15 parts by weight, 1 to 15 parts by weight of binder, and small amounts of antioxidants, fluorescent brighteners, dispersants, etc.

One or more electron-donating colorless dyes may be used in combination.

Examples of binders used in the present invention include styrene-butadiene copolymers, modified acrylamide copolymers, carboxy-modified polyvinyl alcohol, acrylic latex, vinyl acetate copolymers, styrene-maleic anhydride copolymers, and hydroxyethyl cellulose. be able to.

As the thermofusible substance, erucic acid,
Stearic acid, behenic acid, palmitic acid, stearamide, behenic acid amide, stearanilide, stearic acid toluidide, N-myristoyl-p-anisidine, N-myristoyl-p-
phenetidine, 1-methoxycarbonyl-4-N
-stearylcarbamoylbenzene, N-octadecylurea, N-hexadecylurea, N,
N'-didodecylurea, phenylcarbamoyloxidedodecane, p-t-butylphenolphenoloxyacetate, p-phenylphenol-p
-chlorophenoxy acetate, 4,4'-isopropylidene bismethoxybenzene, β-phenylethyl-p-phenyl phenyl ether, 2-p
-chlorobenzyloxynaphthalene, d-benzyloxynaphthalene, 1-benzyloxynaphthalene, 2-phenoxyacetyloxynaphthalene, phthalic acid diphenyl ester, 1-hydroxy-2-naphthoic acid xyl ester, 2-benzoyloxynaphthalene, p-benzyloxybenzoic acid benzyl ester, hydroquinone acetate hydroxynaphthoic acid phenyl, p-methoxycarbonylbenzoic acid butyramide, etc. are used.

These substances are colorless solids at room temperature;
It is a substance that has a sharp melting point at a temperature suitable for copying heating temperatures, that is, around 70 to 130°C.

Examples of waxes include paraffin wax, carnauba wax, microcrystalline wax, polyethylene wax, and higher fatty acid amides such as stearic acid amide, ethylene bisstearamide, and higher fatty acid esters.

Examples of metal soaps include higher fatty acid polyvalent metal salts such as zinc stearate, aluminum stearate, calcium stearate, and zinc oleate.

As the image preservation improving agent, phenol or a derivative thereof in which at least one of the 2nd and 6th positions is substituted with an alkyl group, preferably a branched alkyl group is preferred. Further, those having a plurality of phenol groups in the molecule are preferred, and those having 2 to 3 phenol groups are particularly preferred.
Specific examples of these compounds include bis-[3,3-bis-(2'-methyl-4'-hydroxy-5'-tert-butylphenyl)-butanoic acid] glycol ester, 1,1, 3-tris(2-methyl-4-hydroxy-5-tert-
butylphenyl)butane, 4,4'-thiobis(2
-methyl-6-tert-butylphenol), 2,2'-thiobis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-tert
-butylphenol), 4,4'-butylidenebis(3-methyl-6-
tert-butylphenol), etc.

The amount of these compounds used is 5 to 200 weight percent, preferably 20 to 200 percent by weight, based on the electron-accepting compound.
It is 100% by weight.

Examples will be shown below, but the present invention is not limited only to these examples.

Example 1 Preparation of color former sheet 2-anilino-3, an electron-donating colorless dye
-Methyl-6-diethylaminofluorane, 2
1 g of a 1:1 mixture of -anilino-3-chloro-6-dibutylaminofluorane was dissolved in 30 g of isopropyldiphenylethane. Add this solution to water with 6g of gelatin and 4g of gum arabic dissolved in it.
Add to 50g while stirring and emulsify to make a diameter of 1μ.
After forming oil droplets of ~10μ, 250g of water was added. Add acetic acid to bring the pH to about 4 to cause coacervation, create a wall of gelatin and gum arabic around the oil droplets, and then add formalin.
The pH was raised to 9 and the walls were hardened.

The thus obtained microcapsule dispersion was applied to paper and dried to obtain a color former sheet.

Preparation of color developer sheet 20 g of 2,4-dihydroxy-6-methylbenzoic acid tetrahydrophenyl ester, which is an electron-accepting compound, was dispersed in 200 g of a 5% polyvinyl alcohol aqueous solution, and further 10 g each of kaolin and fine particle calcium carbonate were added. to disperse it well.
It was made into a coating liquid. The obtained coating liquid was applied to paper and dried to obtain a color developer sheet.

When the color former sheet thus prepared was brought into contact with the developer sheet and pressure was applied, a black printed image was instantaneously obtained. This image had high density and excellent light resistance and heat resistance.

Example 2 2-anilino-3-, an electron-donating colorless dye
4 g of methyl-6-N-methyl-N-cyclohexylaminofluorane, 1 g of 2-anilino-3-pentadecyl-6-diethylaminofluorane, and 0.01 g of Tinuvin P were mixed with 5% polyvinyl alcohol (Sapon value 99%, polymerization degree 1000) ) Processed in a sand mill with 50 g of an aqueous solution to obtain a dispersion with an average particle size of 2 μm.
Similarly, 10 g of 2,4-dihydroxybenzoic acid tetrahydrofurfuryl ester was sand milled with 100 ml of a 5% aqueous polyvinyl alcohol solution, and after mixing these two dispersions, 10 g each of kaolin and synthetic calcium carbonate were added. Disperse well, then add 5g of paraffin wax emulsion 50% dispersion (Chukyo Yushi Cellosol #428)
was added to make a coating liquid.

The coating liquid was applied to neutral paper having a basis weight of 50 g/m ² so that the coating amount was 5.8 g/m ² , and dried at 60° C. for 1 minute to obtain a coated paper.

Coated paper is heated by facsimile with energy of 40
When heated and colored at mJ/mm ² , a black printed image was obtained, and the color density was 1.02. Also, use this coated paper
The fog density after being left at 40° C. and 90% RH for 24 hours was 0.06. Further, this recording paper did not cause powder blowing even when it was sandwiched between vinyl sheets.

Example 3 In place of the electron-donating colorless dye of Example 2, 5 g of 2-anilino-3-chloro-6-diethylaminofluorane was used as the electron-donating colorless dye, and as the electron-accepting compound, 2,4, A coated paper was obtained in the same manner as in Example 2, except that 10 g of 6-trihydroxybenzoic acid tetrahydrofurfuryl ester was used.

Coated paper is heated by facsimile with energy of 40
A black impression was obtained when color was developed at mJ/mm ² .
The color density was 1.12.

Comparative Example 1 Coated paper was obtained in the same manner as in Example 3 using 10 g of 2,2-bis-(4-hydroxyphenyl)propane as the electron-accepting compound instead of the electron-accepting compound in Example 3. Ta.

Coated paper is heated by facsimile with energy of 40
When the color was developed by heating at mJ/mm ² , the color density was 0.58.

Comparing Examples 2 and 3 with Comparative Example 1, it is clear that the electron-accepting compound of the present invention has extremely high coloring properties.

Comparative Example 2 A coated paper was obtained in the same manner as in Example 3 except that 10 g of benzyl 2,4-dihydroxybenzoate was used as the electron-accepting compound instead of the electron-accepting compound in Example 3.

Coated paper is heated by facsimile with energy of 40
When color was developed by heating at mJ/mm ² , the color density was 1.05.

Further, the density of the coated paper after being left at 40° C. and 90% RH for 24 hours was 0.81.

Comparing Example 2 and Comparative Example 2, it is clear that the recording paper using the electron-accepting compound of the present invention has excellent heat and humidity resistance.

Claims (1)

[Scope of Claims] 1. A recording material using an electron-donating colorless dye and an electron-accepting compound, characterized in that the electron-accepting compound is a compound represented by the following general formula (). [In the above formula, R ₁ and R ₂ represent a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group, an alkyl group, or an alkenyl group, and R ₃ represents an epoxy ring,
It represents a residue containing a tetrahydrofuran ring or a furan ring, and R ₁ and R ₂ may be combined to form a 5- or 6-membered ring. ]