JPH0358386B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel fluoran derivative and a recording material using the fluoran derivative as a dye precursor. The fluorane derivative used in the present invention is a compound that is extremely useful as a dye precursor for recording materials such as pressure-sensitive recording paper, heat-sensitive recording paper, and current-carrying heat-sensitive recording paper. It is a compound that can be applied to line recording paper, electrostatic recording paper, photosensitive printing materials, stamping materials, type ribbons, ballpoint pen inks, crayons, etc. Conventionally, various fluoran compounds have been used as dye precursors for recording materials, but the fluoran compounds themselves are unstable, or the dyes produced from them have poor fastness to light, moisture, etc. It had drawbacks. An object of the present invention is to provide a novel fluorane derivative having excellent performance, particularly as a dye precursor for recording materials. The fluoran compound used in the present invention is stable in the atmosphere and is a white or slightly colored powder.
When it comes into contact with electron-accepting substances such as benzoic acid, resorcinol, phenols, phenol-formalin resin, or bisphenol A, it almost instantaneously develops a black color, and its coloring performance deteriorates due to discoloration or decomposition during storage. It has excellent performance as a recording material without causing any damage. Furthermore, the developed dye exhibits an extremely deep black color and is also excellent in its fastness to light, moisture, etc. Furthermore, the fluoran derivative of the present invention has a structure in which a fluoran skeleton and a triphenylmethane lactone skeleton are linked, and due to the electronic interaction of these two systems, compared to the case of each alone. Since it is a dye precursor that can develop a darker color tone, another major feature is that the developed color tone is a very deep black color. In addition, although the fluoran derivative of the present invention has extremely low water solubility, it dissolves well in various hydrophobic solvents, so it can prevent contamination during microencapsulation during the production of pressure-sensitive and heat-sensitive recording paper. It is also excellent in terms of reducing the amount. The fluoran derivative of the present invention has the general formula () (In the formula, R ₁ and R ₂ are each independently a hydrogen atom, an allyl group, a cyclohexyl group, a cyclopentyl group, a benzyl group, a phenethyl group, or a C ₁ -C ₄ alkyl group,
R ₃ is a halogen atom, R ₄ is a hydrogen atom or C ₁ to _{C 4}
Represents an alkyl group. ), but in the above general formula (),
Examples of the C ₁ -C ₄ alkyl group include methyl group,
Ethyl group, n-propyl group, iso-propyl group,
Examples include n-butyl group, sec-butyl group, and tert-butyl group. The fluoran derivative of the present invention can be produced by various methods, but one preferred example is the formula () (In the formula, R ₅ is a hydrogen atom or a C ₁ - C ₄ alkyl group,
R ₃ and R ₄ each have the above meaning. ) Diphenylamine derivatives represented by and general formula () (In the formula, R ₁ and R ₂ each represent the above-mentioned meanings.) It is easily produced by reacting a ketone carboxylic acid derivative represented by the following. In the reaction between the compound of the general formula () and the compound of the general formula (), the ratio of the two used is not particularly limited and can be appropriately selected within a wide range, but usually the latter is 1 to 1 to 1% of the former. It is preferable to use about 3 times the molar amount, preferably about 2 times the molar amount. The reaction is carried out in the presence of a dehydration condensation agent, and examples of the dehydration condensation agent used include concentrated sulfuric acid, fuming sulfuric acid, phosphoric anhydride, and polyphosphoric acid. The reaction can be carried out under cooling, at room temperature, or under heating, but it usually proceeds suitably at -20 to 100°C, preferably -10 to 70°C, and the reaction is completed in 1 to 100 hours. finish. Pressure-sensitive recording using the fluorane derivative of the present invention,
When manufacturing recording materials such as thermosensitive recording paper, conventionally known methods can be applied. Pressure-sensitive recording paper using the fluorane derivative of the present invention is disclosed in U.S. Pat.
No. 25054890, No. 2548366, No. 2712507, No.
Manufactured by the method described in No. 2730456, No. 2800457, No. 2800458, etc. In the present invention, a fluoran derivative represented by the general formula () is used as a dye precursor, but other components (for example, an electron-accepting solid acid, a thermofusible substance, etc.) are described in the above-mentioned US patent. You can use a wide variety of things. Hereinafter, the present invention will be explained in more detail with reference to Examples. In the examples, parts and % mean parts by weight and % by weight, respectively. Example 1 6.26 parts of 4'-diethylamino-2'-hydroxybenzophenone-2-carboxylic acid, 2-chloro-4
- 2.19 parts of hydroxydiphenylamine, and 98
A mixture of 100 parts of % sulfuric acid was reacted for 40 hours at room temperature.
After the reaction is complete, the reaction solution is distilled into ice water,
After neutralization with caustic soda, the precipitated crystals were separated, washed with water, and dried. This crude crystal was purified by recrystallization with toluene, and the following formula (1) was obtained. 3.96 parts (yield 50%) of the compound represented by was obtained. Melting point: 253-256°C This compound is a white powder that develops a black-purple color on activated clay. Elemental analysis results C H N Cl Analysis value 42.5 5.31 5.22 4.45 Theoretical value 72.8 5.30 5.30 4.48 Example 2 5.7 parts of 4'-diethylamino-2'-hydroxybenzophenone-2-carboxylic acid, 2-chloro-4
- 2.19 parts of hydroxydiphenylamine, and 96
A mixture of 100 parts of % sulfuric acid was reacted at 50°C for 20 hours.
After the reaction is complete, the reaction solution is distilled into ice water,
After neutralization with caustic soda, the precipitated crystals were separated, washed with water, and dried. This crude crystal was purified by silica gel column chromatography, and the following formula (2) was obtained. 3.44 parts (yield 45%) of the compound represented by was obtained. This compound is a white powder that develops a black-purple color on activated clay. Elemental analysis results C H N Cl Analysis value 72.1 4.85 5.58 4.50 Theoretical value 72.3 4.98 5.50 4.65 Examples 3 to 6 The compounds in Table 1 were produced in the same manner as in Example 1, and the hue on activated clay was I looked into it.

【table】

[Table] Example 7 Three parts of the compound of formula (1) were mixed and ground in 15 parts of a 10% polyvinyl alcohol aqueous solution and 7 parts of water to prepare a dispersion (component A). On the other hand, bisphenol A6
30 parts of 10% polyvinyl alcohol aqueous solution and 12 parts
A dispersion liquid (component B) was prepared by pulverizing the mixture in the same manner in water. Next, 5 parts of component A and 40 parts of component B were mixed, coated on paper, and dried to obtain thermal recording paper. This recording paper quickly turned black when heated with a thermal pen or the like. Further, no self-coloring was observed during the production or storage of this recording paper. The developed dye had high density and excellent light resistance, water resistance, and heat resistance. Example 8 Manufacture of pressure-sensitive copying paper 1 part of the compound of formula (1) was dissolved in 30 parts of alkylnaphthalene, and this was mixed with 6 parts of gelatin and 4 parts of gum arabic.
Add 1 part to 50 parts of water and emulsify with vigorous stirring. After adding another 250 parts of water, acetic acid is added little by little to lower the pH to 5 to cause coacervation. Further lower the pH to 4, and then
Add 1 part of 37% Holimarin. The above operations were performed at 50°C. Next, the mixture is cooled to 10° C. to form a gel, and the pH is further raised to 9, and the microencapsulation operation is completed by leaving it for several hours. The microcapsule dispersion thus obtained was applied to paper and dried. When this paper was brought into contact with paper coated with acidic clay tears (activated clay, acid clay, alapulgite, etc.), phenol-formalin resin, bisphenol A, etc., and pressure or impact was applied, the paper developed a black color very quickly. No self-coloring was observed during the production or storage of this copy paper. The developed dye had high density and excellent light resistance, water resistance, and heat resistance.

Claims (1)

[Claims] 1 General formula () (In the formula, R ₁ and R ₂ are each independently a hydrogen atom, an allyl group, a cyclohexyl group, a cyclopentyl group, a benzyl group, a phenethyl group, or a C ₁ -C ₄ alkyl group,
R ₃ is a halogen atom, R ₄ is a hydrogen atom or C ₁ -C ₄
Represents an alkyl group. ) Fluorane derivative represented by 2 General formula () (In the formula, R ₁ and R ₂ are each independently a hydrogen atom, an allyl group, a cyclohexyl group, a cyclopentyl group, a benzyl group, a phenethyl group, or a C ₁ -C ₄ alkyl group,
R ₃ is a halogen atom, R ₄ is a hydrogen atom or C ₁ -C ₄
Represents an alkyl group. ) A recording material characterized by containing a fluoran derivative represented by: