JPH0710954B2 - Novel fluoran compound and chromogenic recording material using the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a color forming dye having excellent color forming performance by the action of an acidic substance and a color forming recording material using the same. More specifically, the present invention proposes a color forming dye capable of forming a red type, a green type and a black type.

[Conventional technology]

A coloring dye that is colorless or almost colorless in itself but develops color by the action of an acidic substance (hereinafter referred to as "coloring dye").
And a acidic substance (developing agent) that develops the color, and a recording material based on a coloring system is widely used today as, for example, pressure-sensitive copying paper or heat-sensitive recording paper. With the increase in the speed of communication recorders such as Facsimile, it has been demanded to increase the color development speed of heat-sensitive recording paper used therein.

In these recording materials, a dye that develops black mainly is used, but when a dye that develops a color other than black, such as a red-coloring dye and / or a green-coloring dye, is used in combination to adjust the color tone. There is.

In recent years, many proposals have been made for a multicolor coloring thermosensitive recording paper in which several kinds of colors are formed in the thermosensitive recording paper.

Under these circumstances, new color-forming dyes that develop red or green colors have been reviewed and demanded.

3-diethylamino-6-as a conventional red dye
Methyl-7-chlorofluorane 3-diethylamino-7-chlorofluorane Or 3-diethylamino-7,8-benzofluorane However, as a green color-forming dye, 3-diethylamino-5-
Methyl-7-dibenzialaminofluorane 3-piperidino-7-phenylaminofluorane However, 3-diethylamino-
6-methyl-7-phenylaminofluorane 3- (N-dichlorohexylmethylamino) -6-methyl-7-
Phenylaminofluorane Are listed as being put to practical use.

[Means for Solving the Problems] (In the formula, R ₁ , R ₂ and R ₄ represent a hydrogen atom, a halogen atom or an alkyl group, and R ₃ represents a hydrogen atom, a halogen atom,
Alkyl group or -NR ₅ R ₆ represents, and R ₅ and R ₆ represent an amino residue having a hydrogen atom, a phenyl group, a naphthyl group or an aralkyl group, but are not both hydrogen atoms, and R ₁ and R ₂ Alternatively, R ₃ and R ₄ may be combined to form a group represented by —CH═CH—CH═CH—, and the naphthalene nucleus formed at this time may have a hydrogen atom as a substituent. However, R ₃
It was found that the fluorane compound represented by R ₂ is not a methyl group) when it is —NHC ₆ H ₅ ) is a color-forming dye excellent in light resistance that mainly develops red or green color.

In the compound of the general formula (I), the propyl group of the N-propyl-methyl group may be either a normal or isopropyl group, but a normal propyl group is preferable, and a phenyl group and a naphthyl group represented by R ₅ and R _6. Alternatively, the aralkyl group may be substituted with a halogen atom and / or an alkyl group.

To produce a fluorane compound represented by the general formula (I), 1 mol ratio of the benzoic acid derivative represented by (Wherein R ₁ , R ₂ , R ₃ and R ₄ are the same as above) or a reactive derivative thereof, for example, a phenolic hydroxyl group is converted to a lower alkoxy group such as a methoxy or ethoxy group. The derivative is reacted with approximately 1 molar proportion in sulfuric acid. The concentration of sulfuric acid used is preferably 80% or more, and the desired product can be obtained by a reaction at a temperature of 100 to 120 ° C. for 4 to 8 hours.

The alkyl group in the general formula (I) has 1 to 1 carbon atoms.
It is preferably an alkyl group of 8 and may have a side branch. Examples thereof include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an isobutyl group, an amyl group, an isoamyl group, a hexyl group, a pentyl group and an octyl group.

The properties of the fluorane compound represented by the general formula (I) thus obtained are summarized in Table 1. The propyl groups of the N-propylmethylamino group of the fluoran compound of the general formula (I) are all n-propyl groups.

The fluorane compound represented by the general formula (I) of the present invention can of course be used alone to prepare a recording material of a color that develops color, but it is also possible to use a mixture of two or more kinds thereof, or to use another color forming dye. It can be mixed and used.
For example, it is possible to produce a record that develops to black by mixing color-forming dyes of three primary colors of red, blue and green, and to obtain a color close to true black by mixing with a black-based color-forming dye. .

Examples of the color-forming dye that can be used by mixing with the fluorane compound of the present invention include fluoran-based leuco dyes containing the fluoran compound as described above, triphenylmethane-based leuco dyes, phthalide-based leuco dyes and fluorene-based leuco dyes. Can be mentioned. However, the present invention is not limited to these.

Examples of the color-forming recording material produced by using the fluoran compound of the present invention or a mixture thereof with other color-forming dyes include heat-sensitive recording paper and pressure-sensitive copying paper, as well as recording paper by heat-sensitive transfer and electric heat-sensitive recording. Paper, electrophotography using toner containing an acidic substance as a developer, ultrasonic recording paper, photosensitive printing material, electron beam recording paper, marking material, stamp ink,
There are typewriter ribbons, but not limited to these.

The method for producing a heat-sensitive recording paper using the fluoran compound of the present invention is the same as in the case of known color forming dyes, for example, JP-B-39-27579, JP-B-43-4160, and JP-B-45-14039.
Alternatively, it can be produced according to the method described in JP-A-59-7087. That is, for example, a suspension obtained by dispersing fine particles of the fluorane compound of the present invention or a mixture of the fluorane compound and another color forming dye and fine particles of a developer (acidic substance) in an aqueous solution of a water-soluble binder is applied to paper. By thermal drying, a thermosensitive recording paper having excellent color developability can be obtained. When a sensitizer is added to the suspension, it is possible to obtain a heat-sensitive recording paper with extremely high sensitivity. The suspension may further contain a filler, a dispersant, a color image stabilizer, an antioxidant, a desensitizer, an anti-tacking agent, an antifoaming agent, a light stabilizer, a brightening agent and the like. .

In this case, examples of the developer used include bisphenol A, 4,4′-secondary butylidene bisphenol, 4,4′-cyclohexylidene bisphenol, 2,2 ′.
-Dihydroxydiphenyl, pentamethylene-bis (4-
Bisphenol compounds such as hydroxybenzoate), sulfur-containing bisphenol compounds such as 1,7-di (4-hydroxyphenylthio) -3,5-dioxaheptane, benzyl 4-hydroxybenzoate, 4-hydroxybenzoic acid Ethyl acid, propyl 4-hydroxybenzoate, isopropyl 4-hydroxybenzoate, butyl 4-hydroxybenzoate, isobutyl 4-hydroxybenzoate, chlorobenzyl 4-hydroxybenzoate, methylbenzyl 4-hydroxybenzoate,
4-Hydroxybenzoic acid esters such as diphenylmethyl 4-hydroxybenzoate, 4-hydroxy-4'-methyldiphenyl sulfone, 4-hydroxy-4'-isopropoxydiphenyl sulfone, 4-hydroxy-4'-butoxydiphenyl Hydroxysulfones such as enylsulfone, 4-
4-Hydroxyphthalic acid diesters such as dimethyl hydroxyphthalate, dicyclohexyl 4-hydroxyphthalate, and diphenyl 4-hydroxyphthalate, for example, esters of hydroxynaphthoic acid such as 2-hydroxy-6-carboxynaphthalene, hydroxyacetophene Examples thereof include non-, p-phenylphenol, benzyl 4-hydroxyphenylacetate, p-benzylphenol, hydroquinone-monobenzyl ether, and tribromomethylsulfonic acid such as tribromomethylphenyl sulfone.

Examples of the water-soluble binder include polyvinyl alcohol, hydroxyethyl cellulose, carboxymethyl cellulose, styrene-maleic anhydride copolymer salt, styrene-
Examples thereof include, but are not limited to, butadiene emulsion, vinyl acetate-maleic anhydride emulsion, polyacrylate, polyacrylamide, starches, casein, and gum arabic.

Examples of the sensitizer include higher fatty acid amide, benzamide, stearic acid anilide, acetoacetic acid anilide, thioacetanilide, dimethyl phthalate, dibenzyl terephthalate, dibenzyl isophthalate, bis (tart-butylphenol) s such as 4,4′- Dimethoxydiphenyl sulfone, 4-iso-propoxy-4'-n-butoxydiphenyl sulfone, 4,4'-dibutoxydiphenyl sulfone, 4,4'-di-n- (or iso-) pentyloxydiphenyl Diethers of bisphenol S such as sulfone, diphenylamine, carbazole, 2,3-di-m-
Examples thereof include trilyl butane, 4-benzyl biphenyl, 4,4′-dimethyl biphenyl, di-β-naphthyl phenylenediamine, and the like.Examples of the filler include clay, talc, kaolin, satin white, titanium oxide, calcium carbonate. , Magnesium carbonate, barium sulfate, magnesium silicate, aluminum silicate and the like.

Further, examples of the dispersant include sulfosuccinates such as dioctyl sodium sulfosuccinate, sodium dodecylbenzenesulfonate, sodium salt of lauryl alcohol sulfate, fatty acid salt, and the like, and examples of color image stabilizers include salicylic acid derivatives and oxynaphthoate. Antioxidants such as metal salts of acid derivatives (particularly zinc salts) and other water-insoluble zinc compounds can be used as antioxidants.
2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 4,4'-propylmethylenebis (3-methyl-6) -tert-butylphenol), 4,4'-thiobis (2-
tert-butyl-5-methylphenol) and the like, desensitizing agents such as aliphatic higher alcohols, polyethylene glycol, guanidine derivatives, etc., and detackifying agents such as stearic acid, zinc stearate, calcium stearate, carnauba. Examples include wax, paraffin wax, and ester wax.

The method for using the fluoran compound of the present invention in pressure-sensitive copying paper is the same as that for general fluoran compounds, and it is described in U.S. Patent No. 2,548,365, U.S. Patent No. 2,548,366, U.S. Patent No. 2,80.
The pressure-sensitive copying paper can be manufactured according to the method described in US Pat. No. 0,457, US Pat. No. 2,800,458, JP-A-58-112041 or JP-A-58-139738. As the developer used in that case, conventionally known ones are used, for example, acid clay, activated clay, attavarjiite, bentonite,
Inorganic acidic substances such as colloidal silica, aluminum silicate, magnesium silicate, zinc silicate, tin silicate, calcined kaolin and talc, aliphatic carboxylic acids such as silicic acid, maleic acid, tartaric acid, citric acid, succinic acid and stearic acid,
Benzoic acid, p-tert-butylbenzoic acid, phthalic acid, gallic acid, salicylic acid, 3-isopropylsalicylic acid, 3-phenylsalicylic acid, 3-cyclohexylsalicylic acid, 3,5-di-
tert-Butylsalicylic acid, 3-methyl-5-benzylsalicylic acid, 3-phenyl-5- (2,2-dimethylbenzyl) salicylic acid, 3,5-di- (2-methylbenzyl) salicylic acid, 2-hydroxy-1- Aromatic carboxylic acids such as benzyl-3-naphthoic acid, salts of these aromatic carboxylic acids with metals such as zinc, magnesium, aluminum and titanium, p-
Phenol resin-based developer such as phenylphenol-formalin resin, p-butylphenol-acetylene resin,
Examples thereof include a mixture of these phenol resin-based developer and the above-mentioned metal salt of aromatic carboxylic acid.

To use the fluorane compound of the present invention for thermal transfer, for example, JP-A-58-212,985, JP-A-59-33,185, and JP-A-59-42,9.
95 or the method described in JP-A-59-225,986 can be used according to the method described in JP-A-48-96,137, JP-A-48-101,935 or JP-A-49-
For use in the method described in JP-A-11-344, and for use in electrophotography, for example, the method described in JP-A-52-24,530 or JP-A-52-56,932 can be used.

Further, the use of the fluorane compound of the present invention for photosensitive recording is described, for example, in Japanese Examined Patent Publication Nos. 38-24188, 45-10550, and 49.
-45978, JP-A-50-80120, JP-A-50-126228, JP-A-52-
According to the method described in JP-A-141633 or JP-A-54-147829, to use for ultrasonic recording, French Patent No. 2,120,92 is used.
No. 2, for use in electrostatic recording, JP-B No. 49-3932, and for use in photosensitive printing materials, methods described in JP-A No. 48-12104 can be used.

The fluoran compound of the present invention is used for these color-forming recording materials, and is also disclosed in, for example, JP-A-50-75991 or JP-A-60-2.
It is also used as a color-developing component of the reversible temperature indicating material disclosed in Japanese Patent No. 19289.

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto.

Example 1 (Synthesis example) In 110 g of 85% sulfuric acid, 0- (4-Nn-propyl-methylamino-
2-Hydroxybenzoyl) benzoic acid (20.0 g) and 4-chloro-3-methylphenol (9.1 g) were added, and the mixture was stirred at 120-125 ° C for 4 hours, then cooled and poured into ice water, and caustic soda solution was added. The reaction product was deposited and collected by filtration. The precipitate collected by filtration was washed with water, heated with stirring with 88 ml of water, 5 g of caustic soda and 300 ml of toluene, refluxed for 30 minutes, and then allowed to cool and stand. The water layer was removed, the toluene layer was washed with a 3.5% aqueous sodium hydroxide solution and water, a small amount of precipitate was filtered off, 250 ml of toluene was distilled off, and the distillation residue was cooled. The precipitated crystals are collected by filtration, washed with a small amount of toluene and then dried.
21 g of 3-Nn-propyl-methylamino-6-methyl-7-chlorofluorane (Compound 1) was obtained as fine orange-white fine crystals with a melting point of 251-254 ° C.

Example 2 (Synthesis Example) The procedure of Example 1 was repeated using 9.0 g of 4-chloro-phenol instead of 4-chloro-3-methylphenol used in Example 1, and 3-Nn-propyl was used. -Methylamino-7-chlorofluorane (Compound 2) 14.5 g melting point 223
Obtained as pale pink fine crystals at ˜224 ° C.

Examples 3 to 4 (Synthesis Example) In place of 4-chloro-3-methylphenol used in Example 1, 10.0 g of 3,4-dichlorophenol or 10.5 g of 4-tert-pentylphenol was used, respectively. Almost the same operation as in 3-Nn-propyl-methylamino-6,7
17.9 g of dichlorofluorane (compound 3) (melting point 230-232
℃, pink fine crystals), and 3-Nn-propyl-methylamino-7-tert-pentylfluorane (Compound 4) 11.4g
(Melting point 194-197 ° C., pale pink fine crystals) was obtained.

Example 5 (Synthesis Example) In place of 4-chloro-3-methylphenol used in Example 1, 7.8 g of 3-ethylphenol was used.
The same operation was performed, but it is still the target product after the toluene is distilled off.
Since crystals of 3-Nn-propyl-methylamino-6-ethylfluorane did not precipitate and a liquid remained, recrystallization was attempted with isopropyl alcohol and ethanol, but crystallization was not successful. The obtained product is brown carmel-like
It was a substance that melts at 65 ° C. Analysis of this material by NMR showed that it was the desired 3-Nn-propyl-methylamino-6-ethylfluorane (Compound 5). That
The NMR spectrum is shown in FIG.

Examples 6 to 7 (Synthesis example) In 120 g of 67% sulfuric acid, 0- (4-Nn-propyl-methylamino-
2-Hydroxybenzoylbenzoic acid (20 g) and β-naphthol (9.2 g) or α-naphthol (9.2 g) were added, and substantially the same operation as in Example 1 was performed to give 3-Nn-propyl-methylamino-7,8-benzofluorane. (Compound 6) 16.0g
(Melting point 241-244 ° C, pink fine crystals), and 3-Nn-propyl-methylamino-5,6-benzofluorane (Compound 7) 18.7 g (melting point 163-169 ° C, pink fine crystals) were obtained.

Example 8 (Synthesis Example) Substituting 14.7 g of 6-bromo-2-naphthol for the 4-chloro-3-methylphenol used in Example 1 and performing substantially the same operation as in Example 1 26.4 g of fluorane compound (compound 8) (melting point 228-230
C, white fine crystals) were obtained.

Example 9 (Synthesis Example) In place of 4-chloro-3-methylphenol used in Example 1, 14.3 g of 4-ethoxydiphenylamine was used, and an operation similar to that of Example 1 was performed and 3-Nn- Propyl-methylamino-7-anichnofluorane (Compound 9) 1
5.3 g (melting point 201-203 ° C., white fine crystals) were obtained.

Example 10 (thermosensitive recording paper) Glass beads (diameter 1-1.5 m
m) Put it in a polyethylene bottle together with 150g and seal it with Red Dev
A suspension A and a suspension B were obtained by milling for several hours using a paint conditioner manufactured by il. They were mixed 1: 1 to prepare a coating solution.

This coating solution was applied to a white base paper and dried to produce a thermal recording paper (thermosensitive recording paper I).

This heat-sensitive recording paper was heated on both sides at a temperature of 150 ° C. using a dry heat tester (manufactured by Kishino Scientific Machinery Co., Ltd.) to develop color.
Further, a part of this color-developed thermal recording paper was subjected to a light resistance test for 3 hours using a light resistance tester (manufactured by Suga Test Instruments Co., Ltd.).

The color densities of these coloring surfaces were measured with a Macbeth reflection densitometer RD-514 type, and the results are shown in Table 1.

Examples 11 to 12 (thermosensitive recording paper) A thermal recording paper was produced in the same manner as in Example 10 by using the suspensions A-2 and A-3 in place of the suspension A of Example 10 (thermosensitive recording paper II and thermal recording paper II. III).

These thermal recording papers were treated in the same manner as in Example 10,
Further, the color density was measured on the color developing surface before and after the light resistance test. The measured values are shown in Table 2.

Comparative Example 3-N-diethylamino-6-methyl-7-chloro was used as a fluorane compound having a structure similar to that of each of the fluorane compounds of the present invention used in Examples 10, 11 and 12, and was put into practical use. Three kinds of thermal recording papers were prepared in the same manner as in Example 10 using fluorane, 3-N-diethylamino-7-chlorofluorane and 3-N-diethylamino-7,8-benzofluorane (comparison I, Comparative II and Comparative III). These heat-sensitive recording papers were treated in the same manner as in Example 10, and the color densities of the coloring surfaces before and after the light resistance test were measured. The measured values are shown in Table 2 and are compared with Examples 10, 11 and 12.

Table 2 Before light resistance test After light resistance test Thermal recording paper I 0.92 0.91 Comparison I 1.00 0.90 Thermal recording paper II 0.92 0.87 Comparison II 0.97 0.85 Thermal recording paper III 0.15 1.22 Comparison III 1.31 1.19 Example 13 (pressure sensitive copying paper) ) 3-Nn-Propyl-methylamino-6-methyl-7-chlorofluorane 4g was dissolved in 86g of alkylnaphthalene-diallylethane mixed solvent and prepared by in-situ polymerization method using ethylene-maleic anhydride copolymer. An emulsion of microcapsules was obtained. This emulsion was applied to paper and dried to produce a top sheet of pressure-sensitive copying paper.

When the lower leaf paper coated with phenol formalin resin or clay was overlaid on the upper leaf paper and the letters were written, dark pink letters appeared on each lower leaf paper.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location B41M 5/30 C09B 11/28 E 7306-4H 6956-2H B41M 5/18 105 (72) Inventor Takeo Obizu 3-60 Ukima, Kita-ku, Tokyo Inside Shin-Nissan Kako Co., Ltd. (72) Inventor Kimiaki Kinoshita 3-1-160, Ukima, Kita-ku, Tokyo Shin-Nisso Kako Co., Ltd.

Claims (4)

[Claims] 1. A general formula (In the formula, R ₁ , R ₂ and R ₄ represent a hydrogen atom, a halogen atom or an alkyl group, R ₃ represents a hydrogen atom, a halogen atom, an alkyl group or -NR ₅ R ₆ , and R ₅ and R ₆ represent hydrogen. Represents an atom, a phenyl group, a naphthyl group or an aralkyl group, but is not a hydrogen atom together, and R ₁ and R ₂ or R ₃ and
R ₄ may be filed by a group represented by -CH = CH-CH = CH- attached, this time constructed naphthalene nucleus may have a halogen atom as a substituent. However, when R ₃ is -NHC ₆ H ₅ , R ₂ is not a methyl group). 2. A general formula as a color forming component. (In the formula, R ₁ , R ₂ and R ₄ represent a hydrogen atom, a halogen atom or an alkyl group, R ₃ represents a hydrogen atom, a halogen atom, an alkyl group or -NR ₅ R ₆ , and R ₅ and R ₆ represent hydrogen. Represents an atom, a phenyl group, a naphthyl group or an aralkyl group, but is not a hydrogen atom together, and R ₁ and R ₂ or R ₃ and
R ₄ may be filed by a group represented by -CH = CH-CH = CH- attached, this time constructed naphthalene nucleus may have a halogen atom as a substituent. Provided that when R ₃ is —NHC ₆ H ₅ , R ₂ is not a methyl group) and contains at least one fluorane compound. 3. The color-forming recording material according to claim 2, wherein the color-forming recording material is a thermosensitive recording paper. 4. The color-forming recording material according to claim 2, wherein the color-forming recording material is a pressure-sensitive copying paper.