JPH06122269A - Recording material - Google Patents

Abstract

PURPOSE:To obtain a recording material giving the color image having a high density of a color-developing image by containing an indolylphthalide derivative having an indole compound forming ring structure between 1-position and 2-position as a partial skeleton in the electron donative colorless dyes of the recording material. CONSTITUTION:Electron donative colorless dyes and an electron acceptable compound are used as a recording material such as pressure-sensitive paper. An indolylphthalide derivative having an indole compound forming ring structure between 1-position and 2-position as a partial skeleton is contained as the electron donative colorless dyes at that time. An indolylphthalide derivative, in which ring structure shaped between the 1-position and 2-position in the indole section skeleton is composed of a six-membered ring, is comprised. Accordingly, the recording material giving the color image having high density of a color- developing image is acquired.

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 more particularly to a recording material having improved color developability.

[0002]

2. Description of the Related Art Recording materials using an electron-donating colorless dye and an electron-accepting compound are pressure-sensitive paper, thermal paper, photosensitive pressure-sensitive paper,
It is already well known as an electrically conductive recording paper and a thermal transfer paper. For example, British Patent 2140449 and US Patent 44
80052, 4436920, Japanese Patent Publication No. 60-2399.
2, JP-A-57-179836 and 60-12355.
6 and 60-123557. As a recording material, in recent years, studies have been earnestly conducted to improve characteristics such as color density and fastness of a color body. However, almost no attempts have been made to improve the color developability of the indolylphthalide derivative in a recording material using the indolylphthalide derivative as an electron-donating colorless dye. As a result of diligent studies to improve the color development, the first place and the second place
It was found that an indolylphthalide derivative having a partial skeleton of an indole compound in which a ring structure is formed at the position significantly improves color development as compared with conventional indolylphthalide derivatives.

[0003]

SUMMARY OF THE INVENTION The present invention is to provide a recording material using a material having a high color density.

[0004]

The above object is characterized in that the electron-donating colorless dye comprises an indolylphthalide derivative having a partial skeleton of an indole compound having a ring structure at the 1-position and 2-position. Achieved by recording material. Of the indole compounds that form a ring structure at the 1- and 2-positions, the ring structure is 5 to 7 from the viewpoint of ease of synthesis and color development.
A membered ring is preferable, and a 6-membered ring is particularly preferable. Among the indolylphthalide derivatives according to the present invention, those represented by the following general formula (1) are preferable. General formula (1)

[0005]

[Chemical 1]

In the formula, at least one of Ar and Ar 'is an indole partial skeleton represented by the general formula (2),
The other represents an aromatic ring partial skeleton represented by the general formula (3) or (4), and A represents an unsaturated cyclic structure. General formula (2)

[0007]

[Chemical 2]

In the formula, X represents a divalent linking group, and R ¹ represents a hydrogen atom, an alkyl group or an alkoxy group. General formula (3)

[0009]

[Chemical 3]

In the formula, R ² and R ³ may be the same or different and each represents a hydrogen atom, an alkyl group or an aryl group, and R ⁴ represents a hydrogen atom, an alkyl group, an alkoxy group, a substitutable amino group or a halogen atom. Represent General formula (4)

[0011]

[Chemical 4]

In the formula, R ⁵ and R ⁶ may be the same or different and each represents a hydrogen atom, an alkyl group or an aryl group, and R ⁷ represents a hydrogen atom, an alkyl group, an alkoxy group, a substitutable amino group or a halogen atom. Represent

Among the cyclic structures represented by A in the above general formula (1), the following are preferable.

[0014]

[Chemical 5]

Among them, the following are preferable from the viewpoint of suitability for synthesis.

[0016]

[Chemical 6]

In the above general formula (2), among the divalent linking groups represented by X, those represented by the following general formula (5) or (6) are preferable. General formula (5)

[0018]

[Chemical 7]

General formula (6)

[0020]

[Chemical 8]

In the formula, R ⁸ and R ⁹ may be the same or different and each represents a hydrogen atom, an alkyl group, an aryl group, an alkoxy group or a hydroxy group, and n represents an integer of 2 to 4.

In the above general formula (4), the groups represented by R ⁸ and R ⁹ include a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 5 to 12 carbon atoms, and 1 to 6 carbon atoms. The alkoxy group and hydroxy group are preferred. These groups may further have a substituent. Particularly, a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a hydroxy group are preferable.

Specifically, the following is preferable as X.

[0024]

[Chemical 9]

In the above general formula (2), among the groups represented by R ¹ , a hydrogen atom, an alkyl group having 1 to 4 carbon atoms,
An alkoxy group having 1 to 4 carbon atoms and a halogen atom are preferable, and a hydrogen atom, a methyl group, a methoxy group and a chlorine atom are particularly preferable.

In the above general formula (3), the groups represented by R ² and R ³ are preferably an alkyl group having 1 to 15 carbon atoms and an aryl group having 6 to 15 carbon atoms. 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,
It may be substituted with 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, as R ² and R ³ , an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxyalkyl group having 7 to 12 carbon atoms, an alkoxyalkyl group having 2 to 10 carbon atoms, and tetrahydrofurfuryl A group is preferable, and specific examples thereof include a methyl group, an ethyl group, a butyl group, an isobutyl group, an octyl group, a phenyl group, a p-tolyl group, an ethoxyethyl group, a methoxypropyl group, and a tetrahydrofurfuryl group.

The group represented by R ⁴ is preferably a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 15 carbon atoms, a halogen atom or an acylamino group having 2 to 11 carbon atoms. The group may further have a substituent. Of these, a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, and an alkoxy group having 1 to 8 carbon atoms are preferable, and specifically, a hydrogen atom, a methyl group, an isopropyl group, a methoxy group, an ethoxy group, a butyloxy group, and the like are preferable. Can be mentioned.

In the above general formula (4), the group represented by R ⁵ is preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 8 carbon atoms, specifically, a hydrogen atom or methyl. Group, and a phenyl group. The group represented by R ⁶ is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms,
An aryl group having 6 to 10 carbon atoms is preferable, and specific examples thereof include a methyl group, an ethyl group, a butyl group, an octyl group, and a phenyl group. Next, specific compounds of the indolylphthalide derivative according to the present invention will be exemplified, but the present invention is not limited thereto.

[0029]

[Chemical 10]

[0030]

[Chemical 11]

[0031]

[Chemical 12]

[0032]

[Chemical 13]

[0033]

[Chemical 14]

The electron-donating colorless dye according to the present invention is a conventionally known triphenylmethanephthalide compound, fluorane compound, phenothiazine compound, indolylphthalide compound, leucoolamine compound, rhodaminelactam compound. , Triphenylmethane-based compounds, triazene-based compounds, spiropyran-based compounds, fluorene-based compounds 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, and specific examples of fluoranes are U.S. 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 spirodipyrans are U.S. Pat. No. 3,971,808, pyridine compounds and pyrazine compounds are U.S. Pat. No. 3,775,424, No. 3,853,869, No. 4,246,318, and specific examples of fluorene compounds are described in JP-A-63-94878.

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, metal complexes and the like. To be 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 and 1,1-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-methoxyphenoxy ) Ethyl ester, 1,3-bis (4-hydroxyphenyl) propane, 2- (2,4-dihydroxyphenyl) -2-phenylpropane, 3,5-bis (α-methylbenzyl) salicylic acid zinc, 3,5 -Bis (α, α-dimethylbenzyl) zinc salicylate, 3,5
Examples thereof include zinc-bis (α, α-dimethylbenzyl) -6-methylsalicylate and zinc 3,5-di-t-octylsalicylate.

When the recording material of the present invention is used for pressure sensitive paper, US Pat. Nos. 2,505,470 and 2,505,505 are applicable.
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
No. 3, 989,264, 1,091,076 and the like, or the interfacial polymerization method or US Pat.
There is a method described in No. 3,404. Generally, a solvent (alkylated naphthalene, alkylated diphenyl, alkylated diphenylmethane, alkylated terphenyl, chlorinated paraffin, or the like synthetic oil: a vegetable oil such as cotton oil or castor oil is mixed with or without an electron-donating colorless dye. : Animal oil: Mineral oil or mixtures 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 is characterized in 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, the electron-accepting compound and, if necessary, additives are dispersed alone or in a mixture in a binder such as styrene-butadiene latex or polyvinyl alcohol to form a support such as paper, plastic sheet, resin coated paper together with a pigment. A developer sheet is obtained by applying.

As the 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 diameter 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 amount of the electron-donating colorless dye and the electron-accepting compound used depends 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.
44,989, JP-A-1-87291, and the like. Specifically, the electron-donating colorless dye and the electron-accepting compound are 10 μm in the dispersion medium.
Hereinafter, it is preferably used by pulverizing and dispersing to a particle size of 3 μm or less. As the dispersion medium, a water-soluble polymer aqueous solution having a concentration of about 0.5 to 10% is generally used, and dispersion is performed by a ball mill,
It is carried out by using 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 preferably 1:10 to 1: 1 by weight, more preferably 1: 5 to 2: 3.

At this 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
No. 1478, No. 63-235961, JP-A 2-18
No. 4489 and No. 2-215585. These are used at the same time as the electron-donating colorless dye or at the same time as being finely dispersed at the same time as 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 satisfy various requirements. As an example of the additive, in order to prevent contamination of the recording head at the time of recording, an inorganic pigment, an oil absorbing substance such as polyurea filler is dispersed in a binder,
Furthermore, fatty acids, metal soaps, etc. are added to enhance the releasability of the head. 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-proofing agent may be added to these binders for the purpose of imparting water resistance, or an emulsion of a hydrophobic polymer, specifically, a styrene-butadiene rubber latex, an acrylic resin emulsion or the like may be added.

The obtained 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 from the viewpoint of dot reproducibility to use a support having a smoothness of 500 seconds or more, particularly 800 seconds or more as defined by JIS-8119.

[0044]

[Example 1]

1) Preparation of Capsule Sheet Containing Electron-Donating Colorless Dye 5 parts of a partial sodium salt of polyvinylbenzenesulfonic 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, 100 parts of diisopropyl naphthalene in which 6.8% of the compound (2) which is an electron-donating colorless dye is dissolved is emulsified and dispersed in 100 parts of a 5% aqueous solution of a partial sodium salt of polyvinylbenzenesulfonic acid to obtain particles having a diameter of 4.0 μm. An emulsion with a size was obtained. Separately, 6 parts of melamine, 11 parts of 37% by weight formaldehyde aqueous solution,
30 parts of water was 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, p with aqueous phosphoric acid solution
The H was adjusted to 6.0, the liquid temperature was raised to 65 ° C, and 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, 200 parts of a 10% by weight aqueous solution of polyvinyl alcohol and 50 parts of starch particles were added and water was added to prepare a 20% solid concentration solution of the microcapsule dispersion. This coating solution was applied to a 50 g / m ² base paper with an air knife coater so that a solid content of 5 g / m ² was applied, and dried 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 consisting of 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 a 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 so that a solid content of 0 g / m ² was coated and drying.

The surface of the microcapsule sheet containing the electron-donating colorless dye is superposed on the sheet of the electron-accepting compound to give 300 kg.
When a load of / cm ² was applied for color development, the color hue was cyan.

Example 2 A microcapsule sheet was obtained in the same manner as in Example 1 except that the compound (10) was used instead of the compound (2) in Example 1. When color was developed in the same manner as in Example-1, a cyan image was obtained instantaneously.

Example 3 Compound (10) which is an electron-donating colorless dye, bisphenol A which is an electron-accepting compound, and 4-ethoxyphenyl-4 ′ which is a heat-fusible compound.
-Chlorobenzyl ether 20 g each 5% of 100 g
Disperse with a polyvinyl alcohol (Kuraray PVA105) aqueous solution in a ball mill for a whole day and night to obtain a volume average particle size of 3 μm.
And On the other hand, calcined kaolin (Anisilex-93)
80 g of a 0.5% solution of sodium hexametaphosphate 160
It was dispersed with a homogenizer together with g. Dispersing as described above, each dispersion is mixed at a ratio of 5 g of an electron-donating colorless dye dispersion, 10 g of an electron-accepting compound dispersion, 10 g of a heat-fusible compound dispersion, and 22 g of a calcined kaolin dispersion, 4 g of zinc stearate emulsion and 2%
5 g of an aqueous solution of sodium di (2-ethylhexyl) sulfosuccinate was added to obtain a coating liquid. The coating liquid was applied by a wire bar to a dry coating weight on a high-quality paper with a basis weight of 50 g / m ² is 6 g / m ^2, to obtain a coated paper subjected to calendering treatment. The coated paper obtained as described above,
When printed with a thermal head (KLT-216-8MPD1) manufactured by Kyocera Corp., a blue image was obtained.

Comparative Example 1 The compound (2) of Example 1 was converted into (4-dimethylaminophenyl)-(2-methyl-3-).
A microcapsule sheet was obtained in the same manner as in Example 1 except that ethylindol-1-yl) -4-azaphthalide was used. When color was developed in the same manner as in Example-1, a blue image was obtained instantaneously.

Comparative Example 2 Compound (10) of Example 3
To (4-diethylamino-2-ethoxyphenyl)-
A coated paper was obtained in the same manner as in Example 3 except that (2-methyl-3-ethylindol-1-yl) phthalide was used. When a color was developed in the same manner as in Example-3, a blue image was obtained.

The coloring properties (image density) 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. The image densities were each measured with a Macbeth reflection densitometer.

[0052]

[Table 1]

[0053]

According to the present invention, it is possible to obtain a recording material which gives a color image having a high density of a color image.

Claims (2)

[Claims] 1. A recording material using an electron-donating colorless dye and an electron-accepting compound, wherein the indolyl compound having a ring structure between the 1-position and the 2-position as an electron-donating colorless dye has a partial skeleton. A recording material comprising a phthalide derivative. 2. The recording material according to claim 1, wherein the ring structure formed between the 1-position and 2-position in the indole partial skeleton contains an indolylphthalide derivative having a 6-membered ring.