JPS60199065A - Fluoran compound - Google Patents

Abstract

NEW MATERIAL:A fluoran compound shown by the formula I [R1 and R2 are H, 1-8C alkyl, (substituted)phenyl, cycloalkyl, phenylalkyl, or alkoxyalkyl; X is H, 1-4C alkyl, or halogen; Y is H, 1-8C alkyl, Cl, F, or trifluoromethyl], containing benzyl group at the 3-position. EXAMPLE:2-Anilino-3-benzyl-6-diethylaminofluoran. USE:A dyestuff precursor for heat-sensitive recording paper, electrosensitive heat- sensitive recording sheet, or photosensitive coloring recording sheet. PREPARATION:A diphenylamine derivative shown by the formula II (R3 is H, acetyl, or lower alkyl) is reacted with a benzophenone derivative shown by the formula III in the presence of 80-100wt% sulfuric acid at 0-80 deg.C.

Description

[Detailed description of the invention] The present invention relates to novel fluoran compounds.

More specifically, the present invention relates to a novel fluoran compound characterized by having a benzyl group at the 3-position and useful as a dye precursor for use in heat-sensitive recording paper, electrically conductive heat-sensitive recording sheets, and photosensitive color recording sheets. .

Known fluoran compounds related to the present invention are
1-23204, Japanese Patent Publication No. 51-25M80, Japanese Patent Publication No. 56-52759, and Japanese Patent Publication No. 56-162690. The fluoran compounds disclosed in these publications are used as color formers (dye precursors) for heat-sensitive recording paper, electrically conductive heat-sensitive recording paper, pressure-sensitive copying paper, and the like.

However, thermal recording paper using these fluoran compounds as color formers requires a high temperature to obtain a color density of 1.0, that is, a large amount of energy is consumed to reach a practical color density. Furthermore, it had drawbacks in humidity and decoloring resistance, oil resistance, resistance to surface fogging, etc.

As a result of intensive studies to improve the above drawbacks, the present inventors found that a new fluoran compound having a benzyl group at the 5-position represented by the general formula (1) is a colorless or light-colored solid that is stable in the atmosphere. It has been found that when it comes into contact with an acidic substance, it develops a deeper black color, and that the performance as a heat-sensitive recording paper is significantly improved by using this compound.

That is, the present invention provides the following general formula (1), (wherein R,,R
1 is a hydrogen atom, a CI to alkyl group, Cl-
4 a phenyl group, cycloalkyl group, phenylalkyl group or alkoxyalkyl group which may be substituted with an alkyl group or halogen atom, X is a hydrogen atom, a C1-4 alkyl group or a halogen atom, Y is a hydrogen atom, C1
-m represents an alkyl group, chlorine atom, fluorine atom or trifluoromethyl group. ) is a fluoran compound represented by

The novel fluoran compound represented by the general formula (1) of the present invention is produced by the following method.

A diphenylamine derivative represented by the general formula (wherein X and Y are the same as defined above, and R represents a hydrogen atom, an acetyl group, or a lower alkyl group) is the same as the definition in 1.) is reacted with the penzophenolic conductor represented by 1) at a temperature of 0 to 80° C. for several hours in the presence of 80 to 100% sulfuric acid. After the reaction, the reaction mixture is added to water, sodium hydroxide is added to adjust the pH to 6-10, and the precipitate is collected by filtration.

Add toluene and a 5-10% aqueous sodium hydroxide solution to the cake, stir under reflux for 1-3 hours, separate the toluene layer, wash with water, shrink, and collect the precipitated crystals by filtration. . When the crystals are dried, a novel fluoran compound represented by the general formula (1), which is slightly more colored than K, is obtained with high purity and high yield. If necessary, recrystallize from volatile organic solvents such as toluene, acetone, butyl acetate, hexane, etc.

Condensing agents used in the present invention include concentrated sulfuric acid, acetic anhydride, phosphoric acid, polyphosphoric acid, oxysalt phosphorus, and zinc chloride. Benzophenone expressed as a compound is both a solvent and a condensing agent at the same time.1-Next, representative examples of the fluoran compound expressed by the general formula (1) of the present invention are shown. Indicates the hue of the time.

Example 1 2-1 Nilino 3-ben-zyl-6-dinithylaminofluorane (compound, %1).

1c2-(2-hydroxy-4 in 98% sulfur fi150f)
-diethylaminobenzoyl)amic acid, ts.

Add f and dissolve completely while keeping it at about 10℃? ,=
He, 2-benzy-4-methoxydiphenylamine 11
．． 62 was added thereto and reacted for 24 hours at 20-25C, and 1 portion of ice water was added to the reaction mixture, followed by addition of water and an aqueous sodium oxide solution to adjust the pH to 10 or higher.

The precipitate was collected by filtration. Toluene 450 for cake
- and 10% aqueous sodium hydroxide solution 3402 were added and stirred for 2 hours under reflux, then the toluene layer was separated and washed with water, and the toluene was distilled off by steam distillation. The precipitated crystals were collected by filtration, washed with 50 methanol added to the cake, and the crystals were collected again by filtration. When these crystals are dried, 2-1nilino-5-benzyl-6 is whiter than k.
-Siethylinofluorane 1α2f was obtained. The melting point of this fluoran compound was 186-189°C. Also, λmaw in 95% acetic acid solution of this metal compound is
and the molecular extinction coefficient is 449 nm (1,775X1
0') and 591am (t788X104).

A solution obtained by dissolving this product in toluene was colorless and quickly developed color due to the silica gel, giving it a reddish-black color.

Example 2 2-1 Nilino 5-benzyl-6-dipyl 1i nofluorotun (compound layer 2) 2-(2-human Ωx-4-dibutyl 1-inobenzoyl)benzoic acid 20. Add Or,
Add 150f of completely dissolved a2-benzyl-4-methoxydiphenylamine while keeping it at about 10℃, and add 5~1
The reaction was carried out at 0°C for 24 hours.

It was treated in the same manner as in Example 1 and recrystallized from toluene to obtain 16.5 f of white 2-anilino-3-benzyl-6-sibutylaminofluorane.

The melting point of this product was 184 to 185°C, and the solution obtained by dissolving this product in toluene was colorless, but quickly developed color due to the silica gel, giving it a reddish-black color.

Example 3 2-1 Nilino-3-benzyl-6-(N-cyclohexyl-N-methylamino)fluoran [Compound 45] Vc2-(2-hydroxy-4) in 100% sulfuric acid 150
Add 19.1 f of -(N-cyclohexyl-N-methylaino)benzoyl]benzoic acid and completely dissolve while maintaining approximately 0'CK, then process 110 t of 2-benzyl-4-methoxydiphenyl ain at 0 to 2°C. The reaction was carried out for 10 hours. After the reaction, it was treated in the same manner as in Example 1 and recrystallized from ethanol to give a white 2-1nilino-3-benzyl-
14.2 f of 6-(N-cyclohexyl-N-methyl)fluorane was obtained. The melting point of this substance is 155~
The temperature was 160° C., and the solution obtained by dissolving this product in toluene was colorless, but quickly developed color due to the silica gel, giving it a reddish-black color.

Example 4 2-1 Nilino 5-benzyl-6-(N-ethyl-N-
Isoamyl-Aζ)) Fluorane (compound? IA4) Example t of 2-(2-hydro-4-diethyl) 7
iNobenzoyl)benzoic acid 15. 2- instead of Of
[2-Hydroxy-4-(N-ethyl-N-ynamylamino)benzoyl]benzoic acid 192ft:2 was reacted in the same manner as in Example 1, and recrystallized from ethanol.
Whiter 2-1nilino-3-benzyl-6-(N-ethyl-N-ynamylamino)fluoran 12.45F
I got it. The melting point of this product is 105 to 109°C,
A solution obtained by dissolving this product in toluene was colorless, and fortunately the color was developed by the silica gel, giving it a reddish-black color.

Example 5 2-1 Nilino-3-benzyl-6-(N,N-diisoanruai))fluoran [Compound I65] Example 1-2
-(2-hydroxy-4-jethyla ζnobenzoyl)
Benzoic acid 15. 2-(2-hydroxy-4-(N,N-diisoairyl))benzoyl] instead of Of
Benzoin! Using 21.5 f, the reaction was carried out in the same manner as in Example 1, and when recrystallized from ethanol, 2, which was whiter than K, was obtained.
15.6f of -1nilino-3-benzyl-6-(N,N-diisoairiai))fluorane was obtained. The melting point of this product was 172.5 to 175°C, and a solution obtained by dissolving this product in toluene was colorless, but quickly developed color due to the silica gel, giving a reddish-black color.

Next, a general method for producing thermal recording paper using the fluoran compound of the present invention will be described.

A fluoran compound, an acidic substance, and a thermofusible substance (used when the fluoran compound or acidic substance does not melt at the desired temperature) are sufficiently finely ground and mixed with a solution in which the binder is dissolved or dispersed in a solvent or dispersion medium. ,paper,
It is obtained by coating and drying on a support such as a plastic sheet or resin coated paper. When preparing a mixed solution, all the components may be mixed and pulverized at the same time from the beginning, or they may be combined in an appropriate combination, pulverized and dispersed separately, and then mixed.

The amounts of each component constituting the thermal recording paper are 1 part by weight of the fluoran compound, 2 to 10 parts by weight of the acidic substance, and 0 parts by weight of the thermofusible substance.
~10 parts by weight, 2 to 10 parts by weight of binder, and 50 to 150 parts by weight of solvent (dispersion medium).

The solution IN (dispersion t&) is preferably one that does not dissolve either the fluoran compound or the acidic substance, and water is the most preferable solvent (dispersion medium) that can be used, and hydrocarbons such as hexane and ligroin are also suitable. be.

Examples of binders used in the present invention include polyvinyl alcohol, droxyethyl cellulose, polyvinylpyrrolidone, and styrene-maleic anhydride copolymers.

As the thermofusible substance, stearic acid amide, oleic acid amide, ethylene bisstearamide, benzenesulfoanilide, benzyloxyacedoanilide, etc. can be used.

Next, the acidic substance that can be used in the present invention is one that has the property of developing color when it comes into contact with the fluoran compound described above, and specifically, 4-1-butylphenol, 4-phenylphenol, methyl-4- hydroxybenzoate,
4.4'-isoglopylidene diphenol, 4.4F-
Impropylidene (2゜6-dibromophenol), bis(4-hydroxyphenyl)sulfone, benzyl p-hydroxybenzoate, p-hydroxybenzoic acid-1eC
-butyl, 5-(σ-methylbenzyl)salicyl ml
Examples include compounds conventionally known as fx. Note that two or more of these acidic substances can also be used in combination.

Furthermore, various auxiliary agents can be added to the coating liquid. For example, sodium dioctyl sulfoconotate,
Examples include dispersants such as sodium todecylbenzenesulfonate, ultraviolet absorbers such as benzophenone type and triazole type, fine drop foaming agents thereof, fluorescent dyes, and colored dyes.

As the support, paper, plastic film, synthetic paper, woven fabric sheet, etc. are used, and paper is preferably used. The amount of coating on the support is not particularly limited, but is 2 to 15 f/lt/, preferably 3 to 10 fA♂
is within the range of

The heat-sensitive recording paper using the fluoran compound of the present invention will be explained below by giving usage examples.

The performance of the thermal recording paper was determined by the following test method. That is, the skin astringency was measured using a Macbeth RD-514 type reflection density needle. Thermal coloring was performed using a Rhodiaceta type thermotest tester (manufactured by the French National Textile Research Institute) at a heating temperature of 60 to 170°C, a heating time of 3 seconds, and a load of 10.
The test was carried out under the condition of 0 f/ad.

Usage Example 1 A mixture having the following composition was separately ground using a paint conditioner (trade name: Red Devil) to prepare @ solution, ■ solution, and O solution.

■Liquid composition 2-anilino-3-benzyl-6-siethylua is nofluorane 4 parts by weight 10% polyvinyl alcohol aqueous solution 34 heavy Ji[l
i5% antifoaming agent (San Nopco 1407, San Nopco product) 2 parts by weight 0 liquid composition Bisphenol 6 parts by weight 10% polyvinyl alcohol aqueous solution 20 parts by weight Water 1
4 parts by weight 0 Liquid composition 1 Ruium hydroxide 10 parts by weight 10% polyvinyl alcohol aqueous solution 20 parts by weight Water 1
0 parts by weight of liquid, ■liquid, 0 liquid and water in m1J of g:s+:s:3
They were mixed at the li ratio to obtain am for thermosensitive recording paper. After applying this paint to the surface of high-quality paper using a wire bar, the solid weight after drying is St/n? The coated paper was coated so as to have the following properties, placed in a blow dryer, and dried at room temperature to obtain thermal recording paper 0) according to the present invention.

Comparative Example 1 A thermal recording paper for comparison was obtained in exactly the same manner as in Use Example 1, except that liquid O was used instead of liquid (1).

[F] Liquid composition 2-1 Nilino 3-methyl-6-diethyl 1 Minofluorane 4 parts by weight 10% polyvinyl alcohol aqueous solution 54 weight TL 15%
Antifoaming agent (San Nopco 1407) The thermal recording paper according to the present invention and the comparative thermal recording paper obtained in the above manner were tested for coloring sensitivity and background fog. The results are shown in Table 1.

Usage example 2 2-1 Nilino 3-benzyl-6- used in usage example 1
Diethylaminofluorane replacement busy 2-1 Nilino 5
-benzyl-6-diptylinofluorane, 2-1nilino3-benzyl-6-(N-cyclohexyl-N-
Methyl i)) Fluorane, 2-1 Nilino-3-benzyl-6-(N-ethyl-N-isoamyl-i)) Fluoran, 2-1 Nilino-3-benzyl-6-N, N-diynyl-1i-fluorane, 2- 7 Nilino 3-benzyl-6-(N-ethyl-N-p-)lylamino)fluorane, 2-anilino-5-p-methylbenzyl-6-diethylaminofluorane, 2-1 Nilino 5-p-ria
lobenzyl-6-diethylaminofluorane% 2-
o-black g1 nilino 3-benzyl-6-ethyla i
Usage example 1 using nofluorane, 2-0-fluoroanilino 3-benzyl-6-diethyl 1i nofluorane
Thermal recording papers (-) to (nu) were obtained in the same manner as above. Performance tests on these thermal recording papers according to the present invention were carried out in the same manner as in Use Example 1. The results are shown in Table IK.

Note 1) The white part of the uncolored 1IlK heat-sensitive coloring layer.

Note 2) The heating temperature at which a color density of 1.0 is achieved is low, indicating good color development sensitivity.

lJ! of the fluoran compound of the present invention! The printed thermal recording paper has good color development sensitivity and low background density.
It was extremely superior, especially in terms of color development sensitivity, compared to comparative thermal recording papers, and had sufficient practical value as a thermal recording paper for various recording fields, especially for high-speed recording.

Hodogaya Chemical Industry Co., Ltd.

Claims (1)

[Claims] General formula (in the formula, R and %R2 are each a hydrogen atom, CI = own alkyl group, alkyl group of CI to 4 or )) a phenyl group or a cycloalkyl group which may be substituted with a rogen atom , a phenylalkyl group or an alkoxyalkyl group, X is a hydrogen atom, a CI~4 alkyl group or a norogen atom,
Y represents a hydrogen atom, a monoalkyl group of Cr-a, a chlorine atom, a fluorine atom, or a trifluoromethyl group. ) A fluoran compound characterized by having a benzyl group at the 3-position.