JPH0228263A - Fluoran compound and recording material using the same - Google Patents

Abstract

NEW MATERIAL:A compound of formula I (R is H, halogen or lower alkyl). EXAMPLE:3,6-bis-(N-phenyl-N-biphenyl-4-yl-amino)fluoran. USE:Useful as a color former to be used in pressure-sensitive copying paper, heat-sensitive recording paper, temperature-indicating materials and photosensitive color-developing recording sheets. Excellent in light resistance. PREPARATION:A compound of formula II (X is Cl, Br or I) is made to react with a compound of formula III in trichlorobenzene in the presence of zinc chloride and zinc oxide at 200-210 deg.C to prepare a compound of formula IV. Thence, this compound is allowed to react with a biphenyl compound of formula V (X' is Br or I) in the presence of potassium carbonate and copper powder at 190-210 deg.C. After completion of the reaction, the objective compound thus produced is extracted with toluene, which is then distilled off, followed by extracting a biphenyl compound of formula V with ethanol to eliminate this compound.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a novel fluoran compound. More specifically, the present invention relates to pressure-sensitive copying paper, thermal recording paper,
The present invention relates to a fluoran compound useful as a thermochromic material and a color former used in photosensitive color recording sheets.

(Prior Art) Conventionally, colorless color formers, such as benzoylleucomethylene blue, crystal violet lactone, rhodamine B lactam, 2-substituted amino 6-substituted aminofluoranes, or mixtures thereof, are contacted with the color former. Pressure-sensitive copying paper that utilizes a coloring reaction with an adsorbed or reactive compound (hereinafter referred to as a color developer), such as activated clay, or a phenolic compound (for example, U.S. Pat. No. 25054
No. 70) is generally well known. In addition, these coloring agents and acidic substances such as bisphenol A (BPA) and higher alcohols that act as desensitizers,
A thermostatic material that utilizes the fact that ink mixed with higher fatty acids and encapsulated repeats coloring and fading due to temperature changes (
For example, Japanese Patent Publication No. 51-44706) is also well known.

In addition, thermal recording paper, which utilizes the process of dispersing these color formers together with a color developer, coating them on paper, drying them, and then melting them with heat to develop color, has rapidly become popular recently.

The conditions required for color formers used in these fields are:
Common features include a high coloring speed, a high coloring density, a desired hue of the coloring dye, and excellent light resistance and heat resistance of the dye. However, for example, crystal violet lactone is known as a coloring agent that develops a blue color, but its light resistance is insufficient.
No. 580 or JP-A-63-61056 discloses novel fluoran compounds. However, even these color formers cannot be said to satisfy the above requirements, and there is a desire for a more excellent color former.

(Problems to be Solved by the Invention) As a result of intensive studies on color-forming compounds with excellent light resistance, the present inventors have found that their performance as pressure-sensitive copying paper and temperature-indicating materials is significantly improved. .

(Means for Solving the Problems) The present invention is based on the general formula (1) (wherein R represents a hydrogen atom, a halogen atom, or a lower alkyl group, and R may be the same or different.

) and a recording material using the same.

The fluoran compound of the present invention is a colorless or slightly colored solid that is stable in the atmosphere and immediately forms a dark blue pigment when it comes into contact with an acidic substance, and this colored pigment has excellent light resistance.

The fluoran compound of the present invention has the following (1) or (2)
It can be manufactured by the following method.

(1) A compound represented by the general formula (If) (wherein X represents a chlorine, bromine, or iodine atom) was added to the compound represented by the general formula (II) in trichlorobenzene.
I) ■ (In the formula, R represents a hydrogen atom, a halogen, or a lower alkyl group.) By reacting with a compound represented by the following formula in the presence of zinc chloride and zinc oxide at 200 to 210°C, the following general formula A compound represented by (IV) (wherein R is the same as defined in general formula (1)) is obtained. Next, the compound represented by this general formula (rV) and the general formula (V
) (wherein X° represents a bromine or iodine atom) is reacted with a biphenyl compound represented by the formula (X° represents a bromine or iodine atom) in the presence of potassium carbonate and copper powder at a temperature of 190°C to 210”C. After the reaction, the target product is The fluoran compound represented by the general formula (1) is obtained by extracting with toluene, distilling off the toluene, and extracting and removing the excess biphenyl compound represented by the general formula (V) contained in the target product with ethanol. It will be done.

(2) General formula (Vl) (In the formula, R represents a hydrogen atom, a halogen atom, or a lower alkyl group, and R may be the same or different.

) and phthalic anhydride are reacted at 140° C. for 17 hours in the presence of a zinc chloride catalyst.

After the reaction, toluene and water are added and neutralized with soda ash. The toluene layer is separated and the toluene is removed by steam distillation. After cooling, it was filtered, and the cake was washed with methanol and dried at 70°C to obtain pale brown crystals. A fluoran compound represented by general formula (1) is obtained.

The pressure-sensitive copying paper using the fluoran compound of the present invention may contain the above-mentioned coloring agent alone or together with other coloring agents, such as diarylalkane such as alkylated naphthalene, alkylated diphenyl or alkylated diphenylmethane, alkylated terphenyl, etc. It is dissolved in a solvent such as synthetic oil, cotton oil, castor oil, vegetable oil, animal oil, mineral oil, or a mixture of these oils, and then dispersed in a binder or contained in microcapsules. It can be obtained by coating on a support such as a sheet or resin-coated paper.

The amount of coloring agent used depends on the desired coating thickness, the form of pressure-sensitive copying paper,
It is determined by the capsule manufacturing method and other conditions. When encapsulating a coloring agent in a capsule, U.S. Pat.
00,457 and 2,800°458, a method utilizing coacervation of a hydrophilic colloid sol, British Patent No. 867.797, 1,091
The interfacial polymerization method described in , 076, etc. may be used.

Specific examples of color developers that can be applied to this pressure-sensitive copying paper include:
Examples include clays (for example, acid clay, activated clay, attapulgite, kaolin, etc.), phenolic resins, polyvalent metal salts of aromatic carboxylic acids, etc. - Phenolic resins specifically refer to phenol-aldehyde polymers. Combine (
so-called novolac type) and phenolic acetylene polymers.

Polyvalent metal salts of aromatic carboxylic acids are disclosed, for example, in US Pat.
, No. 864,146, No. 3,983.292, No. 3.
No. 934.070, No. 3,983,292, Patent Application No. 1973
3-25158.

The aromatic carboxylic acid in the polyvalent metal salt of an aromatic carboxylic acid is preferably one having a hydroxyl group at the ortho or para position with respect to the carboxy group, and salicylic acid derivatives are particularly preferred; It is particularly preferable to have a substituent such as an alkyl group, an aryl group, or an aralkyl group on at least one of the substituents, and the total number of carbon atoms in the substituents is 8 or more. Among the polyvalent metal salts mentioned above, zinc salts are particularly preferred.

Thermosensitive recording paper is an information paper that records images on a base paper using physical and chemical changes caused by thermal energy, as is clear from, for example, Japanese Patent Application Laid-open No. 184878/1983. The fluoran compound of the present invention can also be suitably used as a coloring agent for heat-sensitive recording paper.

As is clear from, for example, Japanese Patent Publication No. 51-44-706, a thermostatic material changes into a color-forming type or a color-depleting type depending on temperature changes, but the fluoran compound of the present invention is
This temperature-indicating material can also be suitably used.

〔Example〕

Next, the present invention will be explained with reference to examples, but the present invention is not limited thereto in any way.

Example 1 3.6-bis-(N-phenyl-N-biphenyl-4-
Synthesis of (amino) fluorane 43, 11.1 g of ^-dichlorofluoran, 11.2 g of aniline
g, 9.0 g of zinc chloride and 3.4 g of zinc oxide were added to 120 d of trichlorobenzene, and the reaction temperature was increased to 210 d.
After stirring at ℃ for 5 hours, cool and filter. The filter cake was washed with 50°C of toluene, the toluene was removed by drying, and the resulting cake was added to 500d of 2.5% hydrochloric acid, stirred at 90°C for 2 hours, and filtered. 5 more cakes
% soda ash aqueous solution, stirred at 90°C for 1 hour, filtered and washed, and dried at 80°C to obtain dark blue crystals.3.
20.2 g of 6-bis-phenylaminofluorane was obtained.

20.2 g of this precursor and 4-promobiphenyl 4
5.0 g, powdered potassium carbonate 21.6 g, copper powder 1.7
Charge 0.4 g of g1 E and react for 600 hours at 190 to 210"C. After the reaction is complete, add toluene 150 and boil and filter while hot. Toluene is removed by vacuum distillation, and ethanol is added to the residue. Excess 4-promobiphenyl is removed by adding 350- and boiling and filtering while hot.The residue is added to 400 m of n-butanol and boiled for 60 minutes, cooled and filtered.The residue is heated at 90-95°C under reduced pressure. Dried, 3,6-bis-(N-phenyl-N-biphenyl-4
15.7 g of light brown crystals of -yl-amino)fluoran
I got 4. The melting point of this compound is 229.1-235°7℃
It developed a blue spot on silica gel TLC. ”
C-NMR signal specific to fluoran bone core is 83.7
ppm and 169.4 ppm, and the structure was confirmed by detecting a signal of biphenyl newly substituted with nitrogen at 125° cello ppm to 146.1 ppm.

Example 2 3.6-bis-(N-P-)dyl-N-biphenyl-4
-yl-amino)fluoran synthesis 11.1 g of 3,6-dichlorofluorane and 12.9 g of P~toluidine
, 9.0 g of zinc chloride and 3.4 g of zinc oxide were added to 135 g of trichlorobenzene and kept at 210°C for 4 hours.
Stir the time. The subsequent treatments were carried out in the same manner as in Example 1 to obtain 21.8 g of dark blue crystals of 3,6-bis(P-tolylamino)fluorane.

Before this, 121.8 g of H material, 45.0 g of 4-promobiphenyl, 21.6 g of powdered potassium carbonate, 1.7 g of copper powder, and 0.4 g of ice charcoal were prepared and heated at 190 to 210°C for 48 hours. I reacted. Next, treatment was carried out in the same manner as in Example 1, and 3,6-bis-(N-P-)dyl-N-biphenyl-
Pale brown crystals of 4-yl-amino)fluoran 16.2
I got g. The melting point of this compound is 209.0-213.
The temperature was 5° C., and a blue spot developed on silica gel and TLC.

Example 3 Pressure-sensitive copying paper using the fluoran compound of Example 1 3,6-bis-(N-phenyl-N
-biphenyl-4-yl-amino)fluorane (1 part by weight, hereinafter the same) was dissolved in 30 parts of alkylated naphthalene. This solution was added to 50 parts of water in which 6 parts of gelatin and 4 parts of gum arabic had been dissolved, with vigorous stirring, to emulsify it to form oil droplets with a diameter of 1 μm to 10 μm, and then 250 parts of water was added thereto.

Acetic acid was added little by little to bring the pH to about 4 to cause coacervation, creating a wall of gelatin and gum arabic around the oil droplets, and then formalin was added and the pH was raised to 9 to harden the wall. The microcapsule dispersion thus obtained was applied to paper and dried. This pressure-sensitive copying paper had excellent storage stability.

In order to evaluate the characteristics of this pressure-sensitive copying paper,
Pressure equivalent to writing was applied to clay paper, resin paper, and organic acid-based paper. The recording paper used is as follows.

Disperse 20 parts of clay paper acid clay, 0.2 parts of sodium hexametaphosphate, and 80 parts of water using a homogenizer for 5 minutes, and then
% styrene butadiene latex was added to form a clay dispersion.

This dispersion was applied onto high-quality paper to give a dry solid content of 5 g/rrf to obtain clay paper.

20 parts of resin paper p-phenylphenol formalin condensate, 100 parts of calcium carbonate, and 600 parts of a 2% polyvinyl alcohol aqueous solution were dispersed in a ball mill to obtain a phenol resin dispersion.

This dispersion was applied onto high-quality paper at a dry solid content of 5 g/I to obtain a resin.

Organic acid salt paper An organic acid salt paper was obtained in the same manner as in the production of the above-mentioned resin paper except that zinc 3.5α-methyl-benzylsalicylate was used instead of the p-phenylphenol formalin condensate.

When the copying paper containing the fluoran compound of the present invention as a coloring agent was overlapped with each recording paper and pressure was applied, a dark blue printed image was instantaneously obtained. This printed image had a high fresh density and an excellent light fastness value.

The test results are shown in Table 2, using copying paper using crystal violet lactone (CVL), a coloring agent often used in general pressure-sensitive copying paper, as a control example.

Initial density: This is the value measured immediately after color development using a Magbeth reflection densitometer (filter, Wratten #25).

Lightfastness value: The color density after irradiation with light was measured using a fade meter, and the value was calculated using the following formula.

Example 4 Thermal recording paper using the fluoran compound of Example 1 8 g of the compound of Example 1, 10 g of a 10% aqueous polyvinyl alcohol solution, and 12 g of water were ground in a Dyno Mill to obtain a dispersion (referred to as component A). Separately, 4g of bisphenol A
10g of 10% polyvinyl alcohol aqueous solution and 6 ounces of water
g and pulverized with a dyno mill to obtain a dispersion (referred to as component B). 1 g of component A and 6 g of component B are mixed, coated on a support, and dried to obtain heat-sensitive recording paper.

This thermosensitive recording paper developed a blue color when heated using a stamp coloring machine or the like. This colored image had excellent light fastness.

Example 5 Temperature-indicating material using the fluoran compound of Example 1 2 g of the compound of Example 1, 2 g of P-oxybenzoic acid octyl ester, and 10 g of methyl stearate were mixed,
A homogeneous mixture was obtained by heating and melting at 00°C. This mixture developed a blue color at temperatures below 40°C and had excellent light resistance. Moreover, it was colorless at temperatures above 40°C.

(Effects of the Invention) As is clear from the above description, by using the compound of the present invention as a coloring agent, excellent pressure-sensitive copying paper, thermal recording paper, and thermostatic material were obtained.

Hodogaya Chemical Industry Co., Ltd.

Claims (2)

[Claims] (1) A fluoran compound represented by the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R represents a hydrogen atom, a halogen atom, or a lower alkyl group, and R may be the same or different.) (2) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R represents a hydrogen atom, a halogen atom, or a lower alkyl group, and R may be the same or different.) Recording material characterized by containing it as a substance.