JPH0564958A - Recording material - Google Patents

Abstract

PURPOSE:To provide a recording material wherein tinting of its surface caused by light is little, the density of colored image is high, and a black colored image can be given. CONSTITUTION:In a recording material wherein electron-donating non-color dye and electron-accepting compounds are used, 2-N-alkyl-p-trifluoromethyl anilino-6-substituted aminofluoran derivatives, as electron-donating non-color dye, are included.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording material, and in particular,
The present invention relates to a recording material having an improved coloring of the background portion by light.

[0002]

2. Description of the Related Art Recording materials using an electron-donating colorless dye and an electron-accepting compound are already well known as pressure-sensitive paper, heat-sensitive paper, light-sensitive and pressure-sensitive paper, electric heat-sensitive recording paper, heat-sensitive transfer paper and the like. For example, British Patent 2140449 and US Patent 448.
0052, same 4436920, Japanese Patent Publication No. 60-2399.
2, JP-A-57-179836 and JP-A-60-12355.
6 and 60-123557. As a recording material, research has recently been earnestly conducted to improve properties such as (1) color density and (2) fastness of a color body. However, the conventional heat-sensitive recording material has a defect that the background is colored when it is exposed to sunlight for a long time or is displayed under a fluorescent lamp for a long time. Various methods have been devised to improve the discoloration of the background, but the sufficient effect has not always been obtained. (For example, JP-A-50-104
650, the same 58-87093, the same 60-203487,
(61-193883, 61-242878, etc.)

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a recording material using a material which is less colored by light on the background and which satisfies other conditions to be satisfied.

[0004]

The above-mentioned problems are characterized by containing a 2-N-alkyl-p-trifluoromethylanilino-6-substituted aminofluorane derivative as an electron-donating colorless dye. Achieved by the material.

Among the fluorane derivatives having a p-trifluoromethylanilino group at the 2-position, the 3-position needs to be a hydrogen atom in order to obtain a black hue. When the 3-position is substituted with an alkyl group, a halogen atom, an aryl group, an alkoxy group, or the like, the coloring hue becomes a reddish hue. 2-p- in which such a 3-position is a hydrogen atom
Of the trifluoromethylanilino-6-substituted aminofluorane derivative, when the amino group at the 2-position has a hydrogen atom, (A) slightly lower color developability (B) is encapsulated when used in encapsulation. It has drawbacks such as being difficult to dissolve in oil. Although it is possible to improve (B) by introducing an oil-soluble substituent into the amino group at the 6-position,
It is difficult to improve (A).

On the other hand, the fluoran derivative according to the present invention is 2
Although the hydrogen atom of the amino group at the position is substituted with an alkyl group, interestingly, it exhibits a black color during color development. Moreover, it has been found that by substituting with an alkyl group, it also has the unexpected performance of simultaneously improving the above-mentioned color developability and oil solubility. Therefore, among the fluorane derivatives according to the present invention, 2- [N- (p-trifluoromethylphenyl) -N-alkyl] amino-6 in which the 3-position is unsubstituted is used.
-Substituted aminofluorane derivatives are preferred. From the viewpoint of color development, the substituent of the 6-position substituted amino group is at least 1
It is preferably one alkyl group. Among the fluoran derivatives according to the present invention, those represented by the following general formula (1) are preferable. General formula (1)

[0007]

[Chemical 1]

(In the formula, R ¹ is an alkyl group, R ² is an alkyl group, an alkenyl group, an alkynyl group, an aryl group and a hydrogen atom, R ³ is an alkyl group, and ring A may contain a hetero atom. Represents a good aromatic ring. Ring A may have a plurality of the same or different substituents, and the substituent in this case represents an alkoxy group, a halogen atom or a nitro group.)

In the above general formula (1), among the groups represented by R ¹ , an alkyl group having 1 to 16 carbon atoms is preferable. This group further includes an alkyl group having 1 to 10 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a halogen atom, a substituted amino group, a cyano group, and a heterocyclic residue. And the like. These substituents may further have a substituent. Particularly, R ¹ is preferably an alkyl group having 1 to 10 carbon atoms, an aryloxyalkyl group having 7 to 12 carbon atoms, an alkoxyalkyl group having 2 to 10 carbon atoms, or a tetrahydrofurfuryl group.

In the above general formula (1), among the groups represented by R ² , an alkyl group having 1 to 15 carbon atoms and an aryl group having 6 to 15 carbon atoms are preferable. This group further includes an alkyl group having 1 to 10 carbon atoms and 6 carbon atoms.
May be substituted with an aryloxy group having 1 to 12 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a halogen atom, a substituted amino group, a cyano group, a heterocyclic residue or the like. These substituents may further have a substituent. In particular, R ²
As the alkyl group having 1 to 10 carbon atoms, the aryl group having 6 to 10 carbon atoms, the aryloxyalkyl group having 7 to 12 carbon atoms, the alkoxyalkyl group having 2 to 10 carbon atoms, and the tetrahydrofurfuryl group are preferable. .

As the substituted amino group at the 6-position, diethylamino, dibutylamino, diamylamino, dihexylamino, N-ethyl-N-isobutylamino, N-ethyl-
N-isoamylamino and N-ethyl-N-p-tolylamino are preferred.

In the above general formula (1), among the groups represented by R ³ , an alkyl group having 1 to 12 carbon atoms is preferable. This group further includes an alkyl group having 1 to 6 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, a halogen atom, a substituted amino group, a cyano group, and a heterocyclic residue. And the like. These substituents may further have a substituent.
Particularly, R ³ is preferably an alkyl group having 1 to 10 carbon atoms or an alkoxyalkyl group having 2 to 10 carbon atoms.

In the above general formula (1), the ring A is preferably a benzene ring, a naphthalene ring, a pyridine ring, a pyrimidine ring, an indole ring or the like, and particularly preferably a benzene ring. When Ring A is substituted with the same or different substituents, the substituent is preferably a halogen atom, a nitro group, a cyano group, an alkoxy group or the like, and particularly, a chlorine atom,
A fluorine atom is preferred.

Next, specific examples of the fluorane derivative according to the present invention will be shown, but the present invention is not limited thereto. 2-N-methyl-p-trifluoromethylanilino-6-
Diethylaminofluorane, 2-N-ethyl-p-trifluoromethylanilino-6-diethylaminofluorane, 2-N-propyl-p-trifluoromethylanilino-6-diethylaminofluorane, 2-N-butyl- p
-Trifluoromethylanilino-6-diethylaminofluorane, 2-N-hexyl-p-trifluoromethylanilino-6-diethylaminofluorane, 2-N-octyl-p-trifluoromethylanilino-6-diethylamino Fluoran, 2-N- (2-ethylhexyl) -p
-Trifluoromethylanilino-6-diethylaminofluorane, 2-N- (2-ethoxyethyl) -p-trifluoromethylanilino-6-diethylaminofluorane,
2-N-ethyl-p-trifluoromethylanilino-6-
Dibutylaminofluorane, 2-N-ethyl-p-trifluoromethylanilino-6-N'-ethyl-N'-isobutylaminofluorane, 2-N-ethyl-p-trifluoromethylanilino-6- Examples thereof include N'-ethyl-N'-p-tolylaminofluorane and 2-N-ethyl-p-trifluoromethylanilino-6-N'-ethyl-N'-tetrahydrofurfurylaminofluorane.

The electron-donating colorless dye according to the present invention is a conventionally known triphenylmethanephthalide compound, fluorane compound, phenothiazine compound, indolylphthalide compound, leukoauramine compound, rhodaminelactam compound. , A triphenylmethane compound, a triazene compound, a spiropyran compound, a fluorene compound, and the like. Specific examples of the phthalides include US Reissue Patent Specification No. 23,024, US Patent Specification Nos. 3,491,111, and 3,491.
112, 3,491,116 and 3,5.
09,174, specific examples of fluoranes are US Pat. Nos. 3,624,107 and 3,627,787.
No. 3,641,011, No. 3,462,82
No. 8, No. 3,681,390, No. 3,920,5
No. 10, No. 3,959,571, specific examples of spiro dipyrans are US Pat. No. 3,971,808, pyridine compounds and pyrazine compounds are US Pat. No. 3,775,424, Nos. 3,853,869, 4,246,318, and specific examples of fluorene compounds are described in Japanese Patent Application No. 61-240989.

Examples of the electron-accepting compound used in the recording material of the present invention include phenol derivatives, salicylic acid derivatives, metal salts of aromatic carboxylic acids, acid clay, bentonite, novolac resins, metal-treated novolac resins and metal complexes. Be done. Examples of these are Japanese Patent Publication No. 40-930.
9, JP-B-45-14039, JP-A-52-140.
483, JP-A-48-51510, JP-A-57-2
10886, JP-A-58-87089, JP-A-59
-11286, JP-A-60-176795, JP-A-61-95988 and the like.

Examples of the electron-accepting compound include bisphenol A, 2,2-bis (3-methyl-4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) heptane, 1,2. 1-bis (4-hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) -2-ethylhexane, 1,1-bis (3-chloro-4-hydroxyphenyl) -2-ethylbutane Bis (3-allyl-4-hydroxyphenyl) sulfone,
1,7-bis (4-hydroxyphenylthio) -3,5
-Dioxaheptane, (4-hydroxyphenyl)-
(4-isopropoxyphenyl) sulfone, 4-hydroxybenzoic acid benzyl ester, 2,4 dihydroxybenzoic acid-β-phenoxyethyl ester, 2,4 dihydroxybenzoic acid-α-methyl-β- (3-methoxy Phenyloxy) ethyl ester, 1,3-bis (4-hydroxyphenyl) propane, 2- (2,4dihydroxyphenyl) -2-phenylpropane, 3,5-bis (α-methylbenzyl) salicylic acid Zinc, 3,5-bis (α, α
Examples include zinc-dimethylbenzyl) salicylate, zinc 3,5-bis (α, α-dimethylbenzyl) -6-methylsalicylate, and zinc 3,5-di-t-octylsalicylate.

In the recording material of the present invention, an ultraviolet absorber may be used as an auxiliary agent for suppressing the coloring of the background. Examples of these UV absorbers include benzophenone-based UV absorbers, benzotriazole-based UV absorbers, salicylic acid-based UV absorbers, cyanoacrylate-based UV absorbers, and oxalic acid anilide-based UV absorbers. Examples of these are US Pat. No. 2,719,08
6, ibid. 3,707,375, ibid. 3,754,919, ibid. 4,220,711, Japanese Patent Publication No. 36-10466, ibid. 42.
-26187, ibid 48-5496, ibid 48-3048
2, same 48-41572, JP-A-47-10537, same 58-111942, same 58-212844, same 59-.
19945, 59-46646, 59-10905.
5, 63-53544 and the like.

Among these, a benzophenone type ultraviolet absorber or a benzotriazole type ultraviolet absorber is particularly preferable. Specifically, as a benzophenone-based ultraviolet absorber, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-
4-octyloxybenzophenone, 2-hydroxy-
4-dodecyloxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone and the like are preferable, and a benzotriazole ultraviolet absorber As 2 (2'-hydroxy-5'-methylphenyl)
Benzotriazole, 2 (2'-hydroxy-5'-t
-Butylphenyl) benzotriazole, 2 (2'-hydroxy-3 ', 5'-di-t-butylphenyl) benzotriazole, 2 (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5- Chlorbenzotriazole, 2 (2'-hydroxy-3 ', 5'-di-t
-Amylphenyl) benzotriazole, 2 (2'-hydroxy-4'-octyloxyphenyl) benzotriazole and the like are preferable.

The amount of the ultraviolet absorber used is 0.01 to
2.0 g / m ² is preferred.

When the recording material of the present invention is used for pressure-sensitive paper, US Pat. Nos. 2,505,470 and 2,505,505.
No. 471, No. 2,505,489, No. 2,548,3
No. 66, No. 2,712,507, No. 2,730,45
No. 6, No. 2,730,457, No. 3,103,404
Various forms can be adopted as described in the prior patents such as No. 3,418,250, and No. 4,010,038. Most commonly it consists of at least a pair of sheets containing separately an electron donating colorless dye and an electron accepting compound.

Regarding the method for producing capsules, a method utilizing coacervation of hydrophilic colloid sol described in US Pat. Nos. 2,800,457 and 2,800,458, and British Patent 867,797, 950,44
3, U.S. Pat. No. 3,10,989,264, and U.S. Pat. No. 3,10.
There is a method described in No. 3,404. Generally, a solvent (alkylated naphthalene, alkylated diphenyl, alkylated diphenylmethane, alkylated terphenyl, chlorinated paraffin, etc., synthetic oil: a vegetable oil such as cotton oil, castor oil, etc., mixed with an electron-donating colorless dye. : Animal oil: Mineral oil or a mixture of these)
By containing this in a microcapsule and applying it to paper, woodfree paper, plastic sheet, resin-coated paper, etc., a color former sheet can be obtained. The electron-donating colorless dye according to the present invention has a feature that it is more easily dissolved in the solvent used for the above-mentioned microencapsulation, as compared with the conventionally known electron-donating colorless dye. Therefore, the density of the electron-donating colorless dye can be increased, and the color density can be improved. Further, an electron-accepting compound and, if necessary, an additive are mixed alone or mixed and dispersed in a binder such as styrene-butadiene latex or polyvinyl alcohol to form a support such as a paper, a plastic sheet or a resin coated paper together with a pigment. A developer sheet is obtained by applying.

As a binder, it is preferable to use a carboxy-modified styrene-butadiene latex in combination with a water-soluble polymer from the viewpoint of light resistance and water resistance. Further, as the pigment, it is preferable to use calcium carbonate having an average particle size of 5.0 μm or less in an amount of 60% by weight or more based on all pigments from the viewpoint of color developing ability.
The amounts of the electron-donating colorless dye and the electron-accepting compound used depend on the desired coating thickness, the form of the pressure-sensitive recording paper, the capsule manufacturing method, and other conditions, and may be appropriately selected according to the conditions. A person skilled in the art can easily determine this usage amount.

When it is used for thermal paper, it is disclosed in JP-A-62-1.
No. 44,989, Japanese Patent Application No. 62-244,883, and the like. Specifically, the electron-donating colorless dye and the electron-accepting compound are pulverized and dispersed in a dispersion medium to a particle size of 10 μm or less, preferably 3 μm or less. The dispersion medium is generally 0.5 to 10%
A water-soluble polymer aqueous solution having a certain concentration is used, and the dispersion is performed using a ball mill, a sand mill, a horizontal sand mill, an attritor, a colloidal mill or the like. The ratio of the electron-donating colorless dye and the electron-accepting compound used is 1:10 by weight.
Between 1 and 1: 1 is preferred, and further 1: 5 to 2: 3
Is particularly preferred.

At that time, a thermofusible substance may be contained in the thermosensitive coloring layer in order to improve the thermal response. Typical examples of the heat-fusible substance include aromatic ethers, thioethers, esters and / or aliphatic amides or ureides. Examples of these are disclosed in JP-A-58-57989 and JP-A-5-57989.
8-87094, 61-58789, 62-1
09681, 62-2132674, 63-15
1478, 63-235961, Japanese Patent Application No. 1-44
No. 47, No. 1-307070 and the like. These are used at the same time as the electron-donating colorless dye or at the same time as being finely dispersed together with the electron-accepting compound. The amount of these used and the electron-accepting compound are added in a weight ratio of 20% to 300%, and particularly preferably 40% to 150%. If necessary, additives are added to the coating liquid thus obtained in order to meet various requirements. As an example of the additive, in order to prevent the recording head from being soiled during recording, an oil absorbing substance such as an inorganic pigment or polyurea filler is dispersed in the binder to further enhance the releasability of the head. Therefore, fatty acids, metal soaps, etc. are added. Therefore, in general, in addition to electron-donating colorless dyes and electron-accepting compounds that directly contribute to color development, heat-fusible substances, pigments, waxes, antistatic agents, ultraviolet absorbers, defoamers, conductive agents, fluorescent dyes. An additive such as a surfactant is applied on the support to form a recording material. Further, a protective layer may be provided on the surface of the thermosensitive recording layer, if necessary.

Usually, the electron-donating colorless dye and the electron-accepting compound are dispersed and applied in a binder. Water-soluble binders are generally used, and polyvinyl alcohol, hydroxyethyl cellulose, hydroxypropyl cellulose, epichlorohydrin-modified polyamide, ethylene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, isobutylene-anhydrous. Examples thereof include maleic salicylic acid copolymer, polyacrylic acid, polyacrylic acid amide, methylol-modified polyacrylamide, starch derivative, casein, gelatin and the like. Further, a water resistant agent may be added to these binders for the purpose of imparting water resistance, or a hydrophobic polymer emulsion, specifically, a styrene-butadiene rubber latex or an acrylic resin emulsion may be added.

The resulting heat-sensitive coating liquid is applied to high-quality paper, high-quality paper having an undercoat layer, synthetic paper, plastic film and the like. At this time, it is particularly preferable to use a support having a smoothness of 500 seconds or more, particularly 800 seconds or more as defined by JIS-8119, from the viewpoint of dot reproducibility. Examples will be shown below, but the present invention is not limited thereto. In the examples, unless otherwise specified, weight% is indicated.

[0028]

【Example】

Example 1 1) Preparation of Capsule Sheet Containing Electron Donating Colorless Dye 5 parts of a partial sodium salt of polyvinylbenzene sulfonic acid (VERSA, TL500, manufactured by National Starch Co., Ltd.) is dissolved in 95 parts of water. An aqueous sodium hydroxide solution was added to this to adjust the pH to 4.0. On the other hand, an electron-donating colorless dye 2-N-ethyl-p-trifluoromethylanilino-6
100 parts of diisopropylnaphthalene in which 6.8% of dibutylaminofluorane was dissolved in 100 parts of a 5% aqueous solution of a partial sodium salt of polyvinylbenzenesulfonic acid to emulsify to obtain an emulsion having a particle size of 4.0 μm. Obtained. Separately, 6 parts of melamine, 11 parts of 37% by weight formaldehyde aqueous solution, and 30 parts of water were heated and stirred at 60 ° C. to obtain a transparent aqueous solution of melamine formaldehyde prepolymer. This aqueous solution was mixed with the above emulsion. While stirring, adjust the pH to 6.0 with phosphoric acid aqueous solution and maintain the liquid temperature at 65 ° C.
The stirring was continued for 6 hours. The capsule solution was cooled to room temperature and adjusted to pH 9.0 with an aqueous sodium hydroxide solution. To this dispersion was added 200 parts of a 10% by weight polyvinyl alcohol aqueous solution and 50 parts of starch particles,
Water was added to prepare a 20% solids concentration solution of the microcapsule dispersion. This coating solution is applied to a base paper of 50 g / m ² at 5 g /
An air knife coater was applied so that the solid content of m ² was applied, followed by drying to obtain an electron-donating colorless dye-containing capsule sheet.

2) Preparation of electron-accepting compound sheet 3,5-bis (α-methylbenzyl) salicylic acid zinc 1
A dispersion liquid containing 4 parts, 80 parts of calcium carbonate, 20 parts of zinc oxide, 1 part of sodium hexametaphosphate and 200 parts of water was dispersed by a sand glider so that the average particle diameter was 3 μm. To this dispersion, 100 parts of 10% PVA aqueous solution and 10 parts of carboxy-modified SBR latex (as solid content) were added, and water was added so that the solid content concentration became 20% to obtain a coating liquid. This coating solution was applied to 50 g / m ² base paper.
An electron-accepting compound sheet was obtained by coating with an air knife coater and drying so that a solid content of 0 g / m ² was coated.

The surface of the microcapsule sheet containing the electron-donating colorless dye is superposed on the electron-accepting compound sheet to give 400 kg.
When a load of / cm ² was applied for color development, the color hue was black.

Example 2 2-N-ethyl-p-trifluoromethylanilino-6-dibutylaminofluorane of Example 1 was added to 2-N-ethyl-p-trifluoromethylanilino-6-N '. A microcapsule sheet was obtained in the same manner as in Example 1 except that -ethyl-N'-isobutylaminofluorane was used. When color was developed in the same manner as in Example-1, a black image was obtained instantaneously.

Comparative Example 1 2-N-Ethyl-p-trifluoromethylanilino-6-dibutylaminofluorane of Example 1 was added to 2-p-trifluoromethylanilino-6-N'-ethyl-N. A microcapsule sheet was obtained in the same manner as in Example 1 except that ′ -isobutylaminofluoran was used instead. When color was developed in the same manner as in Example-1, a black image was obtained instantaneously.

Example 3 2-N-ethyl-p-trifluoromethylanilino-6-diethylaminofluorane, which is an electron-donating colorless dye, bisphenol A, which is an electron-accepting compound, and a heat-fusible compound 20 g of each 4-ethoxyphenyl-4'-chlorobenzyl ether was dispersed in a ball mill for 24 hours together with 100 g of a 5% polyvinyl alcohol (Kuraray PVA105) aqueous solution to give a volume average particle size of 3 µ. On the other hand, 80 g of calcined kaolin (Anisilex-93) was dispersed by a homogenizer together with 160 g of a 0.5% solution of sodium hexametaphosphate. Dispersing as described above, each dispersion was prepared as follows: 5 g of an electron-donating colorless dye dispersion, 10 g of an electron-accepting compound dispersion, 10 of a heat-fusible compound dispersion.
g, calcined kaolin dispersion liquid 22 g, and further mixed with zinc stearate emulsion 4 g and 2% (2-ethylhexyl) sodium sulfosuccinate solution 5 g
Was added to obtain a coating liquid. This coating solution is applied to a basis weight of 50 g / m ²
The coated paper was obtained by coating with a wire bar so as to have a dry coating amount of 6 g / m ^{2 on} calendered paper and calendering. The coated paper obtained as described above is used by Kyocera Corporation.
When printed with a thermal head (KLT-216-8MPD1) manufactured by K.K., a black image was obtained.

Comparative Example 2 2-N-Ethyl-p-trifluoromethylanilino-6-diethylaminofluorane of Example 3 was replaced with 2-p-trifluoromethylanilino-6-diethylaminofluorane. A coated paper was obtained in the same manner as in Example 3. When a color was developed in the same manner as in Example-3, a black image was obtained.

The image areas and non-image areas (background) of the recording materials obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were evaluated as follows. The results are shown in Table 1. (1) Image Density (Test of Coloring Property) The image density is the density of the black image obtained in Examples 1 to 3 and Comparative Examples 1 and 2, and the non-image density is the density of the white background (yellow value) of the fresh sample. Each was measured with a Macbeth reflection densitometer. (2) Stability of Non-Image Area (Test of Coloring by Light) A weatherometer (manufactured by Atlas Co., USA) was applied to the unrecorded area (background area) of the fresh samples obtained in Examples 1 to 3 and Comparative Examples 1 and 2. ) For 24 hours, the density (yellow value) of the unrecorded area was measured by a Macbeth reflection densitometer and compared with the density of the unrecorded area before the weatherometer irradiation. In this case, a xenon lamp with an output of 6000 W was used as the light source.

[0036]

[Table 1]

[0037]

According to the present invention, it is possible to obtain a recording material in which coloring of a background portion by light is small, a density of a color image is high and a black color image is obtained.

Claims (1)

[Claims] 1. A recording material using an electron-donating colorless dye and an electron-accepting compound, wherein the electron-donating colorless dye is 2-N-alkyl-p-trifluoromethylanilino-6-substituted aminofur. A recording material containing an oran derivative.