JPH0545431B2 - - 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 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 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 the benzyl 2,4-dihydroxybenzoic acid ester disclosed in JP-A No. 58-209590 is used in a heat-sensitive recording material, the recording material is insufficient in terms of moisture and heat resistance, fogging, etc. . <Object of the Invention> Accordingly, an object of the present invention is to provide a recording material that has 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 2 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a halogen atom, or a cyano group. In the above general formula, R may be substituted at any position.

The ortho or para position relative to the group [Formula] is preferred, and the para position is particularly preferred. Among the substituents represented by R in the above general formula, alkyl groups having 2 to 5 carbon atoms, 1 to 5 carbon atoms,
5 alkoxy groups, chlorine atoms, bromine atoms, and cyano groups are preferred, and alkyl groups having 2 to 3 carbon atoms, alkoxy groups having 1 to 3 carbon atoms, and chlorine atoms are 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 electronic colorless dye, it provides a highly concentrated colored image. (ii) Poor water solubility. (iii) Stable without sublimation. (iv) 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 P-isopropylbenzyl ester (2) 2,4-dihydroxybenzoic acid P-methoxybenzyl ester (3) 2,4-dihydroxybenzoic acid P-chlorobenzyl ester (4) 2 , 4-dihydroxybenzoic acid m-chlorobenzyl ester (5) 2,4-dihydroxybenzoic acid O-chlorobenzyl ester, etc. These may be used alone, in combination, or in combination with other electron-accepting compounds (eg, 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 amount of the electron-donating colorless dye and the electron-accepting compound to be used depends 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'-butylidenebis(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(tertbutylthio)-s-triazin-2-yl]amino]2. 6-G-tert
-Butylphenol, etc. 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 2-anilino-3-, an electron-donating colorless dye
5g of chloro-6-diethylaminofluorane
% polyvinyl alcohol (Sapon value 99%, degree of polymerization
1000) Dispersion was carried out overnight in a ball mill with 50 g of an aqueous solution. On the other hand, similarly, 10 g of 2,4-dihydroxybenzoic acid p-chlorobenzyl ester (melting point 138-140°C), which is an electron-accepting compound, was dispersed overnight in a ball mill with 100 g of a 5% polyvinyl alcohol aqueous solution. After the dispersion was mixed, 20 g of kaolin (diyodia kaolin) was added for good dispersion, and 5 g of a 50% dispersion of paraffin wax emulsion (Chukyo Yushi Cellosol #428) 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.
The coated paper was obtained by drying for 1 minute. Coated paper is heated by facsimile with energy of 40
When heated and colored at mJ/mm ² , a black printed image was obtained. The color density was 0.93. Comparative Example 1 A coated paper was obtained in the same manner as in the example except that 10 g of 2,2-bis(4-hydroxyphenyl)propane was used as the electron-accepting compound instead of the electron-accepting compound in the example. Coated paper is heated by facsimile with energy of 40
When color was developed by heating at mJ/ ^mm2 , the color density was 0.58.
It was hot. Comparing Examples and 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 the example except that 10 g of benzyl 2,4-dihydroxybenzoate was used as the electron-accepting compound instead of the electron-accepting compound in the example. Coated paper is heated by facsimile with energy of 40
When heated at mJ/ ^mm2 , the color density was 1.05.
It was hot. Further, after this coated paper was left at 40° C. and 90% RH for 24 hours, the density of the coated paper was 0.21. On the other hand, 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 is an alkyl group having 2 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a halogen atom, or
Represents a cyano group.