JPH078957B2 - Dye manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a dye (aminium salt) having an absorbing effect in the near infrared region.

2. Description of the Related Art Near-infrared absorbing dyes produced by the method of the present invention (the following formula (2)
Compound (aminium salt) is a compound known from Japanese Examined Patent Publication No. 43-25335, which is usually produced by oxidizing a corresponding amine using a silver salt as an oxidizing agent.

Problems to be Solved by the Invention Silver salts are expensive and photosensitive, and handling is troublesome because silver is liberated by light.

Furthermore, when considering the preparation of a recording layer comprising amines to be oxidized and a silver salt, the instability of the silver salt hinders the production of a recording layer exhibiting stable color development characteristics.

Means for Solving the Problems The present inventors have conducted extensive studies to solve the above problems, and as a result, the cupric salts can be excellent oxidizing agents for amines. The present invention has been made to find that a recording layer having excellent storage stability can be obtained. That is, the present invention has the formula (I) [Wherein R represents an alkyl group in the formula (I)] and a cupric salt is reacted with the amines represented by the formula (I) [Wherein R in formula (II) represents the same meaning as in formula (I), and X ⁻ represents the anion of the cupric salt used].

The present invention will be described in detail.

Specific examples of the alkyl group R in the formula (I) include a methyl group, an ethyl group, a propyl group, a butyl group and an octyl group, and specific examples of the cupric salt include fluorination, chloride and odor. Cupric acid, cationized compound, fluorinated compound, cupric acid, perchloric acid, formic acid, acetic acid, trifluoroacetic acid, nitric acid, 6-fluorinated antimonic acid, 6-fluorinated arsenic acid, stearic acid, anaphthenic acid, benzenesulfonic acid, Examples include toluene sulfonic acid cupric salts. The amount of cupric salt to be used is usually a molar ratio to the amines to be oxidized or a little higher.

The amines of formula (I) are oxidized with cupric chloride to give the formula (I
In producing the near-infrared absorbing dye of I), it is usually advantageous to carry out oxidation in an organic solvent. Examples of the organic solvent include hydrophilic organic solvents such as formamides such as dimethylformamide, dimethylsulfoxide, acetone, ethanol, ethanol, propanol, alcohols such as butanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, diethylene glycol monobutyl ether, and triethylene. Examples thereof include glycol or polyglycol monoethers such as glycol monobutyl ether, glycols, pyridines, and the like. When a mixed solvent of these and water or a cupric salt is dissolved to some extent, a hydrophobic organic solvent is used. It can also be used.

The reaction temperature is usually room temperature to 200 ° C, and the more preferable temperature is 50 to 150 ° C. The reaction time varies depending on the cupric salt used, the reaction temperature, the solvent, etc., but is usually 5 minutes to 1 minute.
Time is enough. In particular, when the cupric salt and the amine of formula (I) are completely dissolved in the solvent, the reaction proceeds at room temperature and simultaneously with the mixing of these reagents, and the reaction is completed in a short time.

After the reaction is completed, the reaction solution is passed as necessary to remove the cupric salt, and then water is poured to remove the precipitated crystals. Dye of formula (II) obtained by the method of the present invention (aminium salt)
Has sufficient purity and can be used as it is as an infrared absorber, etc., but if desired, recrystallized with methylcellosolve, ethylcellosolve, acetone, etc. to obtain a dye (aminium salt) of higher purity. It is also possible.

Next, it is also possible to produce the compound represented by the formula (II) on the support by reacting the amines represented by the formula (I) and the cupric salt in a color forming layer provided on the support. is there.

First, when the amines and the cupric salt are contacted and reacted in the color forming layer by heat, the amines of the formula (I) and the cupric salt are separately separated by using a binder as shown below. Atomize. In this case, waxes such as animal and plant waxes, polyethylene waxes, synthetic waxes, and higher fatty acids, higher fatty acid amides, higher fatty acid metal salts, acetylated aromatic amines, aromatic sulfonamide compounds, and phthalimide derivatives are used as sensitizers. It may be added to I) amines. Further, calcium carbonate, magnesium carbonate, silica, talc, clay and the like can be added as a filler.

Examples of binders: methylcellulose, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinyl alcohol, carboxy group-modified polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, starch and its derivatives, casein, gelatin, styrene-maleic anhydride Water-soluble substances such as alkali salts of polymers, alkali salts of iso (or diiso) butylene-maleic anhydride copolymers, or polyvinyl acetate, vinyl chloride / vinyl acetate copolymers, polystyrene,
Water-soluble emulsions such as polyacrylic acid ester, polyurethane, styrene / butadiene / acrylic acid type copolymers.

The fine particles (color former component) containing the amines of the formula (I) thus obtained and the fine particles (color developer component) containing the cupric salt have a molar ratio of the amines and the cupric salt. A thermosensitive coloring layer is provided by mixing and mixing so as to have an approximately equimolar ratio or a cupric salt slightly less than the equimolar ratio, and coating it on a support such as ordinary cellulose paper, synthetic paper, plastic sheet, etc. and drying. Obtain a thermosensitive recording sheet. For this purpose, the amines and the cupric salt are contacted and reacted with each other by using a hot plate such as a thermal head heated to a temperature of 100 to 200 ° C. to form an aminium salt of the formula (II) in the thermosensitive coloring layer. Excuse me.

Since the thermosensitive recording sheet which is colorless or slightly green is colored in green according to the pattern of the heating plate, the colored (colored) image can be irradiated with a laser beam or the like to be read as a recorded image.

In the case of preparing a heat-sensitive recording sheet, other additives which do not adversely affect ground coloration or color development, for example, a fluoran compound for black color development and its developer or sensitizer may coexist, or on the surface of the heat-sensitive color developing layer. A protective coat layer may be provided.

Further, a pressure-sensitive recording sheet is prepared by forming a layer containing an amine of the formula (I) as a color-developing agent on the lower leaf paper and a layer containing a cupric salt as a color-developing agent on the upper leaf paper by a conventional method. It is also possible to stack them and pressurize them for coloring (coloring).

The method of the present invention makes it possible to oxidize an aminium salt from an amine by a simple method with an inexpensive raw material without using an expensive and cumbersome silver salt. Since cupric chloride is stable as an oxidizing agent, it can be used as a heat-sensitive or pressure-sensitive coloring dye by producing an aminium salt on a support.

Examples The present invention will be described in more detail with reference to Examples.

Example 1 The following formula (1) A solution of 9.3 g of the above compound in 300 ml of dimethylformamide (DMF) and 1.71 g of CuCl ₂ .2H ₂ O in 50 ml of DMF was added. Immediately developed a dark green color. After stirring for 30 minutes, the crystals were poured into 300 ml of water, and the precipitated crystals were washed with water and dried.

The following green equation (2) Recrystallized from acetone to obtain 9.8 g of crude crystals of
It was confirmed to be the same as the standard product synthesized by the method described in 335.

Example 2 The following equation (3) Was dissolved in 300 ml of dimethylsulfoxide (DMSO), and 2.38 g of cupric HOFT's cuprate in 50 ml of DMSO was added, and the same procedure as in Example 1 was carried out to obtain the following formula (4). To obtain 9.0 g of dark green crystals.

Example 3 7.6 g of the above compound was dissolved in 300 ml of diethylene glycol monobutyl ether, and 2.30 g of cupric bromide was added to 50 ml of the same solvent.
The solution was melted, the temperature was raised to 90 ° C., and the reaction was performed for 30 minutes. 8.9 g of the compound of

Example 4 In Example 1, the amount of CuCl ₂ .2H ₂ O was increased to 2.5 g,
The compound of formula (2) was obtained in a higher purity by the same procedure as in Example 1 except that the reaction was carried out for 0 minutes.

Example 5 Instead of 9.3 g of the compound of formula (1), the compound of formula (7) The same procedure as in Example 1 was carried out except that 1.03 g of the compound of 11.9 g of green crystals of

Example 6 Instead of CuCl ₂ .2H ₂ O in Example 1, 3.9 g of Cu (ClO ₄ ) ₂ or
Using 5.9 g of Cu (SbF ₆ ) _{2, the} same operation as in Example 1 was carried out to obtain a compound of formula (2) of dark green color in which the counter ion was ClO ₄ ⁻ , SbF ₆ ⁻ instead of Cl ^−. 10.3g, 1 each
1.8 g was obtained.

Example 7 By using 1.35 g of CuCl ₂ instead of 1.71 g of CuCl ₂ · 2H ₂ O of Example 1, 10.3 g of the compound of the formula (2) was obtained.

Example 8 Solution A Compound of formula (1) described in Example 1 20 g 10% polyvinyl alcohol water 40 g water 40 g solution B solution naphthenic acid cupric 2 g stearate amide 8 g 10% polyvinyl alcohol 90 g A, B Each was crushed and dispersed in a separate ball mill. Next, the dispersion liquids were mixed at the following ratio to prepare a coating liquid.

Liquid A 10 g Liquid B 10 g Calcium carbonate (20% dispersion liquid) 80 g Immediately apply 50 g / m ² of base paper to a coating amount of ² g / m ^{2 on} one side of the base paper and dry to give an extremely light green color. A thermosensitive recording paper was obtained.

When heat-sensitive printing was performed on this recording paper at a head temperature of 110 ° C., yellow-green printing according to the formula (2) was obtained and it was possible to read with a semiconductor laser beam.

EFFECTS OF THE INVENTION In producing a corresponding aminium salt by oxidizing a specific amine, a method has been found for obtaining a target substance with high purity and high yield without using an expensive and cumbersome silver salt.

Further, it becomes possible to produce an aminium salt by reacting the same amines and cupric salt in the color forming layer, and heat-sensitive or pressure-sensitive color recording using this can be realized.

Claims (2)

[Claims] 1. A formula (I) [Wherein R represents an alkyl group in the formula (I)] and a cupric salt is reacted with the amines represented by the formula (II) [Wherein R in formula (II) has the same meaning as in formula (I) and X ⁻ represents the anion of the cupric salt used]. 2. A method of reacting the amines with the cupric salt in a color-forming layer provided on a substrate containing the amines of the formula (I) and the cupric salt. Range 1st
The manufacturing method described in the item.