JPH0460036B2 - - 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 using a novel electron-accepting compound.

The electron-accepting compound according to the present invention is particularly useful as an electron-accepting compound for pressure-sensitive recording materials and heat-sensitive recording materials. It is a compound that can be applied to electron beam recording sheets, electrostatic recording sheets, photosensitive printing plates, stamping materials, type ribbons, ballpoint pen inks, crayons, etc.

<Prior art> The use of various phenol compounds as electron-accepting compounds in 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 cannot necessarily be said to be satisfactory electron-accepting compounds. That is, when used in combination with an electron-donating colorless dye, the color density is not sufficient.

Furthermore, when 2,4-dihydroxybenzoic acid benzyl ester disclosed in JP-A-58-209590 is used in a heat-sensitive recording material, the recording material is insufficient in terms of moisture and heat resistance, fogging, etc. .

<Objective of the Invention> Accordingly, an object of the present invention is to provide a recording material with sufficient color density when used in combination with an electron-donating colorless dye.

<Structure of the Invention> The object of the present invention has been achieved by a recording material characterized in that it uses an electron-donating colorless dye and a compound represented by the following general formula as an electron-accepting compound.

In the above formula, R represents an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a chlorine atom, or a hydrogen atom.

In the above general formula, the substitution position may be anywhere, but The ortho or para position relative to the group is preferred, and the para position is particularly preferred.

When the electron-accepting compound according to the present invention is used 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.

(i) When combined with an electron-donating colorless dye, it provides a highly concentrated colored image.

(ii) Poor water solubility.

(iii) Stable without sublimation.

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

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-dihydroxybenzoic acid β-phenethyl ester (2) 2,4-dihydroxybenzoic acid β-p-chlorophenylethyl ester (3) 2,4-dihydroxybenzoic acid β-p-tolylethyl ester (4) 2,4-dihydroxybenzoic acid β-p-methoxyphenylethyl ester (5) 2,4-dihydroxybenzoic acid α-phenethyl ester, etc. These may be used alone or in combination or with other electron-accepting compounds (e.g. , bisphenol A, 4-hydroxybenzoic acid benzyl ester, etc.).

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 (i.e., crystal violet lactone);
3,3-bis(p-dimethylaminophenyl)phthalide, 3-(p-dimethylaminophenyl)-3
-(1,3-dimethylindol-3-yl)phthalide, 3-(p-dimethylaminophenyl)-3
-(2-methylindol-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-chloroanilino)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-m-chloroanilino-6-diethylaminofluorane, 2-(3,4-dichloroanilino)
-6-diethylaminofluorane, 2-octylamino-6-diethylaminofluorane, 2-dihexylamino-6-diethylaminofluorane, 2-m-trichloromethylanilino-6-diethylaminofluorane, 2-butylamino-3
-Chloro-6-diethylaminofluorane, 2-
Ethoxyethylamino-3-chloro-6-diethylaminofluorane, 2-anilino-3-chloro-6-diethylaminofluorane, 2-diphenylamino-6-diethylaminofluorane, 2-
Anilino-3-methyl-6-diphenylaminofluoran, 2-anilino-3-methyl-5-chloro-6-diethylaminofluoran, 2-anilino-3-methyl-6-diethylamino-7-methylfluoran, 2-anilino-3-methoxy6-
Dibutylaminofluorane, 2-o-chloroanilino-6-dibutylaminofluorane, 2-p-
Chloranilino-3-ethoxy-6-diethylaminofluoran, 2-phenyl-6-diethylaminofluoran, etc.; thiazine compounds include benzoylleucomethylene blue, p-nitrobenzylleucomethylene blue, etc.; spiro compounds include: 3-Methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran, 3,3'-dichloro-spiro-dinaphthopyran, 3-benzylspiro-dinaphthopyran, 3-
Examples include methyl-naphtho(3-methoxy-benzo)-spiropyran and 3-propyl-spiro-dibenzopyran. 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 may be used alone or in combination, and a solvent (synthetic oils such as alkylated naphthalene, alkylated diphenyl, alkylated diphenylmethane, and alkylated terphenyl; vegetable oils such as cotton oil and castor oil; animal oil; mineral oil; or The color former sheet can also be prepared by dissolving the color former in a mixture of the color former (e.g., a mixture of An electron-accepting compound, alone or in combination with other electron-accepting compounds, is dispersed in a binder such as styrene-butadiene latex or polyvinyl alcohol, and applied to a support such as paper, plastic sheet, resin-coated paper, etc. A developer sheet is thereby obtained.

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. It is easy for one skilled in the art to determine this amount to use.

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 produced by sufficiently finely pulverizing and mixing an electron-donating colorless dye, an electron-accepting compound according to the present invention, and, if necessary, a thermofusible substance, in a liquid in which a binder is dissolved or dispersed in a solvent or dispersion medium. In addition, kaolin, calcined kaolin, talc,
Oil-absorbing pigments such as waxite, diatomaceous earth, calcium carbonate, aluminum hydroxide, magnesium hydroxide, magnesium carbonate, titanium oxide, barium carbonate, 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 paper, plastic sheet, resin-coated paper, etc. 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.

Further, the coating liquid may be poured into the support.

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 part by weight of an electron-donating colorless dye.
~6 parts by weight, 0 to 30 parts by weight of thermofusible substance, 0 pigments
~15 parts by weight, 1 to 15 parts by weight of binder, and 20 to 300 parts by weight of dispersion medium (solvent).

One or more electron-donating colorless dyes may be used in combination. Water is most desirable as the dispersion medium (solvent).

Examples of binders used in the present invention include styrene-butadiene copolymers, alkyd resins, acrylamide copolymers, vinyl chloride-vinyl acetate copolymers, styrene-maleic anhydride copolymers, synthetic rubbers, gum arabic, polyvinyl alcohol, and hydroxyethyl cellulose. etc. can be mentioned.

Especially in relation to the dispersion medium (solvent), gum arabic,
Water-soluble binders such as polyvinyl alcohol, hydroxymethyl cellulose, carboxymethyl cellulose are preferred.

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, 2-benzyloxynaphthalene, 1-benzyloxynaphthalene, 2-phenoxyacetyloxynaphthalene, diphenyl phthalate, 1-hydroxy-2-naphthoic acid phenyl ester, 2-benzoyloxynaphthalene , p-benzyloxybenzoic acid benzyl ester, hydroquinone acetate, 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 the heating temperature for copying, that is, around 70 to 160°C.

Examples of waxes include paraffin wax, cownabar 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.

Examples of image preservation improving agents include phenols or derivatives thereof in which at least one of the 2nd or 6th positions is substituted with an alkyl group, and among these, one or more of the 2nd or 6th positions is substituted with a tert-butyl group. phenols or derivatives thereof are 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-(4'-hydroxy-
3′-tert-butylphenyl)-butanoic acid] glycol ester, bis[3,3-bis-(4′-hydroxy-3′,
4'-di-tert-butylphenyl)butanoitsquacid] glycol ester, bis[3,3-bis-(2'-methyl-4'-hydroxy-5'-tert-butylphenyl)-butanoitsquacid] glycol ester , 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 4,4'-thiobis(3-methyl-6-tert-
butylphenol), 4,4'-thiobis(2-methyl-6-tert-
butylphenol), 2,2'-thiobis(4-methyl-6-tert-
butylphenol), 2,2'-methylenebis(4-methyl-6-
tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-
tert-butylphenol), 4,4'-butylidene bis(3-methyl-6-
tert-butylphenol), 4,4'-methylenebis(2,6-ditert-butylphenol), 2-tert-butyl-4-tert-butoxyphenol, 2,2-dimethyl-4-isopropyl-7-
tert-butyl-6-chromanol, 2,2-dimethyl-6-t-butyl-5-benzofuranol, 4[[4,6-bis(tert-butylthio)-s-
triazin-2-yl]amino]2,6-di-
Examples include tert-butylphenol.

The amount of these compounds used is 5 to 200 weight percent, preferably 20 percent by weight, based on the electron accepting compound.
~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- which is an electron-donating colorless dye
1 g of methyl-6-diethylaminofluorane was dissolved in 30 g of alkylated naphthalene. Add this solution to water with 6g of gelatin and 4g of gum arabic dissolved in it.
Add to 50g of water while stirring vigorously to emulsify, and reduce the diameter
After forming oil droplets of 1 μ to 10 μ, 250 g of water was added. Acetic acid was added little by little to bring the pH to about 4 to induce coacervation, creating a wall of gelatin and gum arabic around the oil droplets, and then formalin was added and the pH was raised to 9 to harden the wall.

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

Preparation of color developer sheet 20g of 2,4-dihydroxybenzoic acid-β-phenylethyl ester, which is an electron-accepting compound, was
% polyvinyl alcohol aqueous solution 200g,
Further, 20 g of kaolin (diyodia kaolin) was added and well dispersed to form a coating liquid. The obtained coating liquid was applied to paper and dried to obtain a color developer sheet.

When the thus prepared color former sheet and color developer sheet were brought into contact with each other and pressure or impact 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
5 g of methyl-6-N-methyl-N-cyclohexylaminofluorane was dispersed overnight in a ball mill with 50 g of a 5% aqueous solution of polyvinyl alcohol (saponification degree 99%, degree of polymerization 1000). On the other hand, similarly,
5% of 10 g of 2,4-dihydroxybenzoic acid β-phenylethyl ester, which is an electron-accepting compound.
Dispersion was carried out overnight in a ball mill with 100 g of polyvinyl alcohol aqueous solution, and after mixing these two types of dispersions, 20 g of kaolin (diyodia kaolin) was added and dispersed well. #428) 5g was added to prepare a coating liquid.

The coating liquid was applied onto a base paper having a basis weight of 50 g/m ² so that the solid content was 6 g/m ² and heated at 60°C.
After drying for 1 minute, a coated paper was obtained.

Apply energy to heat coated paper using facsimile
When heated and colored at 40 mJ/mm ² , a black impression was obtained. The color density was 1.03.

Further, the density of the coated paper after being left at 40° C. and 90% RH for 24 hours was 0.14.

Example 3 5 g of 2-anilino-3-chloro-6-diethylaminofluorane was used as the electron-donating colorless dye in place of the electron-donating colorless dye in Example 2, and an electron-accepting compound was used in place of the electron-accepting compound. A coated paper was obtained in the same manner as in Example 2 using 10 g of 2,4-dihydroxybenzoic acid-α-phenylethyl ester as the compound.

Apply energy to heat coated paper using facsimile
A black impression was obtained when color was developed at 40 mJ/mm ² .
The color density was 0.95.

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.

Apply energy to heat coated paper using facsimile
When heated at 40mJ/ ^mm2 , the color density was 0.58.
It was hot.

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.

Apply energy to heat coated paper using facsimile
When heated at 40mJ/ ^mm2 , the color density was 1.05.
It was hot.

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.

Example 4 2-anilino-3-methyl-6-N-ethyl-
20g of N-isoamylfluorane in 10% polyvinyl alcohol (saponification degree 98% polymerization degree 500) aqueous solution 100%
The mixture was dispersed with g in a 300 ml ball mill overnight to obtain a dispersion (A). Similarly, 10 g of 2,4-dihydroxybenzoic acid-α-phenylethyl ester was dispersed overnight in a 300 ml ball mill with 100 g of a 10% polyvinyl alcohol aqueous solution to obtain a dispersion (B). Similarly, bis-[3,3-bis(4'-hydroxy-3'-
tert-butylphenyl)-butanoic acid]
20g of glycol ester was mixed with 100g of 10% polyvinyl alcohol aqueous solution in a 300ml ball mill.
Dispersion was carried out day and night to obtain a dispersion liquid (C).

Dispersion liquid (A), dispersion liquid (B) and dispersion liquid (C) at 3:20:5
Mix at a weight ratio of 200g of the mixed liquid,
50 g of calcium carbonate fine powder was added and sufficiently dispersed to form a coating liquid.

This heat-sensitive recording coating liquid was applied onto base paper having a basis weight of 50 g/m ² using an air knife to obtain a coating amount of 6 g/m ² in terms of solid content, and dried at 50°C for 2 minutes to obtain heat-sensitive recording paper. Ta.

When the coated paper was colored by facsimile, a black image was obtained.

Moreover, the storage stability of the obtained color image was extremely excellent.

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 represents an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a chlorine atom, or a hydrogen atom.