JP2566623B2 - Fluoran compound and recording material using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a novel fluoran compound. More specifically, the present invention relates to a fluoran compound useful as a color former for pressure-sensitive copying paper, heat-sensitive recording paper, temperature-sensitive material, and light-sensitive color recording sheet.

(Prior Art) Conventionally, a substantially colorless color former such as benzoyl leuco methylene blue, crystal violet lactone, rhodamine B lactam, 2-substituted amino-6-substituted aminofluorane or a mixture thereof is contacted with this color former. Pressure-sensitive copying paper utilizing a coloring reaction with an adsorbing or reactive compound (hereinafter referred to as a color developer) that develops color by, for example, activated clay or a phenol compound (for example, US Pat. No. 250547).
No. 0) is generally well known. Further, by mixing these color formers with an acidic substance such as bisphenol A (BPA) and a higher alcohol or a higher fatty acid which acts as a desensitizer, the encapsulated ink is repeatedly colored and erased by a temperature change. The temperature indicating material used (for example, Japanese Patent Publication No. 51-44706) is also well known.

Further, a heat-sensitive recording paper utilizing the fact that these color-forming agents are dispersed together with a color-developing agent, applied on paper, dried, and then melted by heat to develop a color, has recently been rapidly spread.

The conditions required for color formers used in these fields are that the color development speed is high, the color density is high, the coloring dye has a desired hue, and the dye has excellent light resistance and heat resistance. And so on. However, for example, crystal violet lactone is known as a color-developing agent that develops blue color, but its light resistance is insufficient, and in order to improve this drawback, JP-A-61-23358 is used.
No. 0 or JP-A-63-61056 discloses a novel fluoran compound. However, even these color formers cannot be said to satisfy the above requirements, and the appearance of more excellent color formers is desired.

(Problems to be Solved by the Invention) As a result of intensive studies on a color forming compound having excellent light resistance, the present inventors have found that the performance as a pressure sensitive copying paper or a temperature indicating material is remarkably improved. .

(Means for Solving the Problems) The present invention has the general formula (I) (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 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 air, and forms a dark blue dye immediately on contact with an acidic substance, and this dye that develops color has excellent light fastness.

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

(1) General formula (II) (Wherein X represents a chlorine, bromine or iodine atom) in trichlorobenzene, the compound represented by the general formula (II
I) (Wherein R represents a hydrogen atom, halogen, or a lower alkyl group) is reacted at 200 to 210 ° C. in the presence of zinc chloride and zinc oxide to give a compound represented by the following general formula (IV): A compound represented by the formula (wherein R is the same as defined in the general formula (III)) is obtained. Next, the compound represented by the general formula (IV) and the general formula (V) A biphenyl compound represented by the formula (X 'represents a bromine or iodine atom) is reacted at a temperature of 190 ° C to 210 ° C in the presence of potassium carbonate and copper powder. After the reaction, the desired product is extracted with toluene, the toluene is distilled off, and the excess biphenyl compound represented by the general formula (V) contained in the desired product is extracted and removed with ethanol to give the compound of the general formula (I). The fluoran compound represented is obtained.

(2) General formula (VI) (Wherein R represents a hydrogen atom, a halogen atom, or a lower alkyl group, and R may be the same or different) and phthalic anhydride in the presence of a zinc chloride catalyst at 140 ° C. for 7 hours. React. After the reaction, toluene and water are added and a neutralization treatment is performed with soda ash. The toluene layer is separated and the toluene is removed by steam distillation. After cooling, the cake is washed with methanol and dried at 70 ° C. to obtain a fluorane compound represented by the general formula (I) having light-colored crystals.

The pressure-sensitive copying paper using the fluorane compound of the present invention may contain the above-mentioned color former alone or together with other color formers, for example, alkylated naphthalene, alkylated diphenyl, diarylalkane such as alkylated diphenylmethane, alkylated terphenyl, etc. Dissolved in a solvent such as synthetic oil, cotton oil, vegetable oil such as castor oil, animal oil, mineral oil or a mixed oil thereof, dispersed in a binder or contained in a microcapsule, and then paper, plastic It can be obtained by applying it to a support such as a sheet or resin coated paper.

The amount of the color former used is determined depending on the desired coating thickness, the form of the pressure-sensitive copying paper, the capsule manufacturing method, and other conditions. When encapsulating the color-forming agent in a capsule, US Pat.
2,800,457 and 2,800,458 method utilizing the coacervation of a hydrophilic colloid sol,
The interfacial polymerization method described in British Patent Nos. 867,797 and 1,091,076 may be used.

Specific examples of the color developer that can be applied to this pressure-sensitive copying paper include clays (eg, acid clay, activated clay, attapulgite, kaolin, etc.), phenolic resins, polyvalent metal salts of aromatic carboxylic acids, and the like. be able to. Phenolic resins are specifically phenol-aldehyde polymers (so-called novolac type) and phenol acetylene polymers. Polyvalent metal salts of aromatic carboxylic acids include, for example, U.S. Patents 3,864,146, 3,983,292, and 3,934,07.
No. 0, 3,983,292 and Japanese Patent Application No. 53-25158.

The aromatic carboxylic acid in the polyvalent metal salt of the aromatic carboxylic acid is useful for those having a hydroxyl group at the ortho or para position with respect to the carboxy group, among which salicylic acid derivatives are preferred, and for the hydroxyl group, the ortho or para position. It is particularly preferable that at least one of them has a substituent such as an alkyl group, an aryl group and an aralkyl group, and the total number of carbon atoms of the substituent is 8 or more. Of the above polyvalent metal salts, zinc salts are particularly desirable.

Thermal recording paper is information paper for recording an image on a base paper by utilizing physical and chemical changes due to heat energy, as is clear from JP-A-60-184878, for example. An image is formed by the fact that the color developer melts and reacts to develop a color, and the fluoran compound of the present invention can also be used favorably as a color developer for this thermal recording paper.

For example, as is clear from Japanese Patent Publication No. 51-44706, the temperature-indicating material changes to a color-developing system or a decoloring system depending on the temperature change, but the fluorane compound of the present invention is also suitable for this temperature-sensitive material. Can be used for

〔Example〕

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

Example 1 3,6-bis- (N-phenyl-N-biphenyl-4-
Synthesis of (yl-amino) fluorane 3,6-dichlorofluorane 11.1 g, aniline 11.2 g, zinc chloride 9.0 g and zinc oxide 3.4 g were added to trichlorobenzene 120 ml, and the reaction temperature was kept at 210 ° C and stirred for 5 hours. After cooling, cool and filter. The filter cake is washed with 50 ml of toluene and the toluene is removed by drying, and the obtained cake is added to 500 ml of 2.5% hydrochloric acid water, stirred at 90 ° C. for 2 hours and filtered. 5% more cake
Add to the soda ash solution, stir at 90 ° C for 1 hour, filter and wash, and dry at 80 ° C to obtain dark blue crystals, 3,6-bis-
20.2 g of phenylaminofluorane was obtained. This precursor 2
Charge 0.2 g and 4-bromo-biphenyl 45.0 g, powdered potassium carbonate 21.6 g, copper powder 1.7 g, and iodine 0.4 g, 190-210 ℃
React for 60 hours. After the reaction is completed, 150 ml of toluene is added and the mixture is boiled and filtered while hot. Toluene is removed by distillation under reduced pressure, 350 ml of ethanol is added to the residue, and the mixture is boiled and filtered while hot to remove excess 4-bromo-biphenyl. The residue is added to 400 ml of n-butanol, boiled for 60 minutes, cooled and filtered. The residue was dried under reduced pressure at 90 to 95 ° C. to obtain 15.7 g of pale brown crystals of 3,6-bis- (N-phenyl-N-biphenyl-4-yl-amino) fluorane. The melting point of this compound was 229.1 to 235.7 ° C, and a single blue color was developed by silica gel TLC. ^13C -NMR detected signals unique to fluoran skeleton at 83.7ppm and 169.4ppm, and detected signals of biphenyl newly substituted with nitrogen from 125.6ppm to 146.1ppm.
The structure was confirmed by the detection.

Example 2 3,6-bis- (NP-tolyl-N-biphenyl-4
Synthesis of -yl-amino) fluorane 11.3 g of 3,6-dichlorofluorane, 12.9 g of P-toluidine, 9.0 g of zinc chloride and 3.4 g of zinc oxide were added to 135 ml of trichlorobenzene and stirred at 210 ° C for 4 hours. . The subsequent treatment was carried out in the same manner as in Example 1 to obtain 21.8 g of dark blue crystal, 3,6-bis (P-tolylamino) fluorane.

21.8 g of this precursor and 45.0 g of 4-bromo-biphenyl,
Powdery potassium carbonate (21.6 g), copper powder (1.7 g) and iodine (0.4 g) were charged and reacted at 190 to 210 ° C for 48 hours. Then, the same treatment as in Example 1 was carried out to give 3,6-bis- (N-P-tolyl-N-
16.2 g of pale brown crystals of biphenyl-4-yl-amino) fluorane were obtained. The melting point of this compound is 209.0-213.5 ℃
And a single blue color was developed on silica gel and TLC.

Example 3 Pressure-sensitive copying paper using the fluorane compound of Example 1 3,6-bis- (N-phenyl-N) obtained in Example 1
1 part of (-biphenyl-4-yl-amino) fluorane (parts by weight, and so on) was dissolved in 30 parts of alkylated naphthalene. This solution was added to 50 parts of water prepared by dissolving 6 parts of gelatin and 4 parts of gum arabic with vigorous stirring to emulsify,
After forming oil droplets having a diameter of 1 μ to 10 μ, 250 parts of water was added. Acetic acid was added little by little to bring the pH to about 4 to induce coacervation, a wall of gelatin and gum arabic was made around the oil droplets, formalin was added and the pH was raised to 9 to harden the wall. The microcapsule dispersion thus obtained was coated on paper and dried. This pressure sensitive copying paper had excellent storage stability.

In order to evaluate the characteristics of this pressure-sensitive copying paper, a pressure corresponding to writing was applied over clay paper, resin paper and organic acid salt paper. The recording paper is as follows.

Clay paper 20 parts acid clay, 0.2 parts sodium hexametaphosphate, 80 water
Parts were dispersed for 5 minutes with a homogenizer, and 5 parts of 50% styrene butadiene latex was further added to obtain a clay dispersion liquid.

This dispersion was applied onto wood free paper so that the dry solid content was 5 g / m ² , to obtain clay paper.

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

This dispersion was applied onto a high-quality paper so that the dry solid content was 5 g / m ² , to obtain a resin paper.

Organic acid salt paper In the production of the resin paper, the organic acid acid salt paper was obtained in the same manner by using zinc 3,5α-methyl-benzylsalicylate instead of the p-phenylphenol formalin condensate.

The copy paper using the fluorane compound of the present invention as a color-developing agent gave a dark blue image instantaneously when pressure was applied while overlapping the recording paper. The fresh density of this printed image was high and the light fastness was excellent.

The test results are shown in Table 2 using a copy paper using a crystal violet lactone (CVL), which is a color-developing agent often used for general pressure-sensitive copy paper, as a control example.

Initial density: The density immediately after color development is measured with a Magbeth reflection densitometer (filter, Ratten # 25).

Light fastness value: a value obtained by measuring the color density after light irradiation with a fade meter and using the following formula.

Example 4 Thermosensitive recording paper using the fluorane compound of Example 1 8 g of the compound of Example 1 is pulverized with 10 g of a 10% aqueous polyvinyl alcohol solution and 12 g of water with a dynomill to obtain a dispersion (component A). Separately, 4 g of bisphenol A and 10 g of a 10% aqueous solution of polyvinyl alcohol and 6 g of water are pulverized with a dyno mill to obtain a dispersion (designated as component B). 1 g of component A and 6 g of component B are mixed, and this is coated on a support and dried to obtain a thermosensitive recording paper.

This heat-sensitive recording paper developed a blue color when heated with a slump color machine or the like. This color image had excellent light resistance.

Example 5 Thermophilic material using fluorane 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 and heated to 100 ° C. to homogeneity. A different mixture was obtained. This mixture developed a blue color at 40 ° C. or lower and its light resistance was also excellent. It was colorless above 40 ° C.

(Effect of the Invention) As is clear from the above description, by using the compound of the present invention as a color former, excellent pressure-sensitive copying paper, heat-sensitive recording paper and temperature-sensitive material were obtained.

Claims (2)

(57) [Claims] 1. A general formula (Wherein R represents a hydrogen atom, a halogen atom, or a lower alkyl group, and R may be the same or different). 2. General formula A recording material containing a fluoran compound represented by the formula (wherein R represents a hydrogen atom, a halogen atom, or a lower alkyl group, and R may be the same or different) as a color-forming substance.