JP6844977B2 - New water-soluble diimonium compound or salt thereof, and aqueous composition - Google Patents

Description

The present invention relates to a diimonium compound or a salt thereof having a wide absorption in the near infrared region, and an aqueous composition thereof. The present invention relates to an aqueous solution which is not particularly a deleterious substance, has excellent water solubility and high storage stability, and an infrared absorbing water-soluble composition using the aqueous solution.

Near-infrared absorbing dyes having absorption in the near-infrared region of 700 to 2000 nm include, for example, the field of optical information recording media such as CD-R, the field of printing such as thermal CTP, flash toner and laser heat-sensitive recording, and the field of heat blocking film. Applications to various industrial applications are being studied. Further, it is also used in a near-infrared cut filter used for PDP and the like, a film for adjusting plant growth, etc. by utilizing the characteristic of a near-infrared absorbing dye that selectively absorbs light in a specific wavelength range. Furthermore, by dissolving or dispersing the near-infrared absorbing dye in a solvent to form an ink, it is possible to use it as a near-infrared absorbing ink that cannot be visually recognized and can be read only by a near-infrared detector or the like. Inks such as near-infrared absorbing inks are roughly classified into water-based inks and organic solvent-based inks depending on the main component of the solvent that dissolves or disperses the near-infrared absorbing dye. There is a strong demand, and the development of a near-infrared absorbing dye having high solubility in water (aqueous medium) is desired.

The diimonium compound has a wider absorption wavelength range than other infrared absorbing dyes, and is widely used in near infrared absorbing filters, heat insulating films, sunglasses and the like. However, since most of them have low solubility in water (water-based medium), so far, mainly as organic solvent-based inks, the purpose has been to study for the purpose of improving robustness and safety, and to improve the solubility in solvents. (Patent Documents 1 to 3).
On the other hand, similar to cyanine compounds and oxonor compounds, diimonium compounds as water-soluble near-infrared absorbers have also been developed (Patent Documents 4 to 7).

Water-soluble diimonium compounds whose counterions are antimonate hexafluoride and arsenic hexafluoride are conventionally known, but most of them are deleterious substances and dangerous substances and are subject to various laws and regulations. Therefore, for example, in the industrial field where the use of heavy metals and the like is regulated, particularly in the field of electrical materials, the development of compounds containing no of these metals is desired. If it is an intramolecular salt-type diimonium compound that does not have a counterion, it is high because it does not contain heavy metals, etc., and it is considered that the range of use will be widened. ) No diimonium compound with excellent solution stability has been found so far.

Japanese Patent No. 3699464 Japanese Patent No. 4800769 Japanese Patent No. 4553962 Japanese Unexamined Patent Publication No. 2001-42511 Japanese Unexamined Patent Publication No. 2008-144004 Japanese Unexamined Patent Publication No. 2001-181184 Japanese Unexamined Patent Publication No. 2002-173474

An object of the present invention is a diimonium compound (near-infrared absorbing dye) that does not contain heavy metals, has high solubility in water (aqueous medium), and has excellent storage stability when used as a water (sexual) solution. An object of the present invention is to provide an aqueous composition containing a diimonium compound (infrared absorbing dye).

As a result of diligent research to solve the above-mentioned problems, the present inventor has found that the above-mentioned problems can be solved by a diimonium compound having a specific structure or a salt thereof, and has completed the present invention.
That is, the present invention
(1) The following formula (1)

(In formula (1), X represents an integer of 1 to 3), a water-soluble diimonium compound or a salt thereof.
(2) The water-soluble diimonium compound according to the previous item (1) or a salt thereof, wherein X in the formula (1) is 3.
(3) An aqueous composition containing the water-soluble diimonium compound according to the preceding paragraph (1) or (2) or a salt thereof and an aqueous medium.
Regarding.

The novel water-soluble diimonium compound of the present invention represented by the above formula (1) or a salt thereof has high solubility in water (aqueous medium), and by using a water (sexual) solution containing the compound or a salt thereof. , An aqueous composition having excellent storage stability can be provided.

The present invention will be described in detail below.
The diimonium compound of the present invention represented by the above formula (1) or a salt thereof is a water-soluble compound that functions as a near-infrared absorbing dye.
Unless otherwise specified, the carboxy group is represented in the form of a free acid in the present specification. Further, in the following description of the present specification, the diimonium compound or a salt thereof is simply referred to as "diimonium compound".

The diimonium compound of the present invention has a structure represented by the above formula (1).
In the formula (1), X represents an integer of 1 to 3, and is preferably 3.

The diimonium compound of the present invention also exists as a free acid or a salt thereof. Examples of the salt that can be formed include salts with inorganic or organic cations. Examples of salts of inorganic cations include alkali metal salts and ammonium salts such as lithium salt, sodium salt and potassium salt (NH ₄ ^+). Specific examples of the organic cation include, but are not limited to, quaternary ammonium represented by the following formula (10).

In the formula (10), Z ^{1 to} Z ⁴ are independently hydrogen atoms, 1 to 4 alkyl groups having 1 to 4 carbon atoms, 1 to 4 alkyl groups having 1 to 4 hydroxy carbon atoms, or 1 to 4 hydroxy carbon atoms and 1 to 4 alkyl groups having alkoxy carbon atoms. At ^{least one of Z 1 to} Z ⁴ is a group other than a hydrogen atom.

Specific examples of the alkyl group having 1 to 4 carbon atoms represented by ^{Z 1 to} Z ^{4 in} the formula (10) include a methyl group and an ethyl group.
^{Specific examples of the hydroxycarbon number 1 to 4 alkyl group represented by Z 1 to} Z ^{4 in} the formula (10) include a hydroxymethyl group, a hydroxyethyl group, a 3-hydroxypropyl group, a 2-hydroxypropyl group, and a 4-hydroxybutyl group. Groups, 3-hydroxybutyl groups, 2-hydroxybutyl groups and the like can be mentioned.
Specific examples of the hydroxycarbon number 1 to 4 alkoxycarbon number 1 to 4 alkyl group represented by ^{Z 1 to} Z ⁴ of the formula (10) are hydroxyethoxymethyl group, 2-hydroxyethoxyethyl group, 3- (hydroxyethoxy). Examples thereof include a propyl group, a 3- (hydroxyethoxy) butyl group and a 2- (hydroxyethoxy) butyl group.

Examples of the salt formed by the diimonium compound of the present invention include alkali metal salts such as sodium salt, potassium salt and lithium salt, monoethanolammonium salt, diethanolammonium salt, triethanolammonium salt, monoisopropanolammonium salt, diisopropanolammonium salt and Organic quaternary ammonium salts such as triisopropanol ammonium salt, ammonium salts and the like are preferable, and lithium salt, sodium salt and ammonium salt are more preferable.

The diimonium compound of the present invention can be synthesized, for example, by the method described below.
First, an intermediate compound represented by the following formula (A) is synthesized according to the method described in JP-A-2005-336150.

Next, the intermediate compound represented by the formula (A) obtained above is hydrolyzed in hydrochloric acid at a reaction temperature of 60 to 100 ° C. to obtain an intermediate compound represented by the formula (B). The obtained intermediate compound represented by the formula (B) is oxidized in an aqueous solution with a bis (trifluoromethanesulfonyl) imide silver salt under the conditions of a reaction temperature of 30 to 80 ° C. and a pH of 5 to 10. A diimonium compound represented by the formula (1) can be obtained.

The diimonium compound represented by the formula (1) of the present invention obtained by the above method can be isolated as a solid free acid by adding a mineral acid such as hydrochloric acid, and the obtained solid free acid can be obtained. Inorganic salts (inorganic impurities) contained as impurities, such as sodium chloride and sodium sulfate, can be removed by washing with water or acidic water such as hydrochloric acid water. After removing impurities, a wet cake of the free acid of the diimonium compound of the present invention or a dry solid thereof can be treated with a desired inorganic or organic base in water to obtain a solution of a salt of the corresponding compound. Examples of the inorganic base include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkali metal carbonates such as lithium carbonate, sodium carbonate and potassium carbonate; and ammonium hydroxide (water ammonia). ; Etc. can be mentioned. Examples of the organic base include, but are not limited to, organic amines corresponding to the quaternary ammonium represented by the above formula (10), for example, alkanolamines such as diethanolamine and triethanolamine.

Specific examples of the diimonium compound represented by the formula (1) are shown below, but the present invention is not limited thereto.

The aqueous composition of the present invention contains a diimonium compound represented by the above formula (1) and an aqueous medium.
The content of the diimonium compound represented by the formula (1) in the aqueous composition of the present invention is usually 0.1 to 20% by mass, preferably 0.2 to 10% by mass, and more preferably 0.2 to 5% by mass. %.

Examples of the aqueous medium include water or a water-soluble organic solvent. Examples of the water-soluble organic solvent include alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, t-butanol, pentanol and benzyl alcohol; ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol and polyethylene glycol. , Polyhydric alcohols such as polypropylene glycol, glycerin, trimethylolpropane, 1,3-pentanediol and 1,5-pentanediol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, tri Glycol derivatives such as ethylene glycol monoethyl ether, triethylene glycol monobutyl ether and dipropylene glycol monomethyl ether; amines such as ethanolamine, diethanolamine, triethanolamine and morpholin; 2-pyrrolidone, NMP, 1,3-dimethyl-imidazole Examples include liginone. These solvents may be used alone or in combination of two or more.

Acids or alkalis may be added to the aqueous composition of the present invention.
Examples of the acid that can be added to the aqueous composition include inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid, and organic acids such as oxalic acid and citric acid.
Examples of the alkali that can be added to the aqueous composition include alkali metal hydroxides such as sodium hydroxide, lithium hydroxide and potassium hydroxide, and alkali metal carbonates such as sodium carbonate, lithium carbonate and potassium carbonate. The content of the acid or alkali that can be added to the aqueous composition is usually 0.1 to 30% by mass, preferably 0.2 to 20% by mass, and more preferably 0.3 to 15% by mass.

The aqueous composition of the present invention is used in the field of optical information recording media such as CD-R, the field of printing such as thermal CTP, flash toner and laser heat-sensitive recording, the field of heat-shielding film, and the near-infrared cut filter used for PDP and the like. It is useful for applications such as films for adjusting plant growth.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. In the examples, the maximum absorption wavelength of the compound obtained by synthesis was measured and evaluated by a spectrophotometer "UV-3150 manufactured by Shimadzu Corporation".

Example 1 (Synthesis of the diimonium compound of the present invention represented by the following formula (4))
20 parts of the intermediate represented by the following formula (2) synthesized by the method described in JP-A-2005-336150 was added to 100 parts of 23% hydrochloric acid, stirred at 90 ° C. for 8 hours, and then cooled to room temperature. 20 parts of sodium chloride was added to the obtained reaction solution, and the mixture was stirred at room temperature for 30 minutes, and then the precipitated solid was filtered off to obtain 40 parts of an intermediate represented by the following formula (3) as a wet cake. The obtained wet cake was added to 200 parts of water, adjusted to pH 6.5 with an aqueous sodium hydroxide solution, and dissolved. The temperature of the obtained solution was raised to 50 ° C., 31 parts of bis (trifluoromethanesulfonyl) imide silver salt was added, the mixture was stirred for 3 hours, filtered, and the filtrate was adjusted to pH 4.5 with 35% hydrochloric acid at room temperature. did. The solid precipitated by stirring for 30 minutes was filtered and separated, washed with water and dried to obtain 10 parts of a diimonium compound represented by the following formula (4). The maximum absorption wavelength of the diimonium-based compound in an aqueous solution having a pH of 7 to 10 was 1062 nm.

Comparative Example 1 (Synthesis of a diimonium compound for comparison represented by the following formula (5))
By air-oxidizing the intermediate represented by the above formula (3) obtained in Example 1, Table 1, No. 1 of Japanese Patent Application Laid-Open No. 2001-181184. A free acid of the diimonium compound represented by No. 15 (a diimonium compound represented by the following formula (5)) was obtained.

Comparative Example 2 (Synthesis of a comparative cyanine compound represented by the following formula (6))
A water-soluble cyanine compound represented by the following formula (6) was obtained according to the method described in JP-A-63-334777.

(A) Solubility test Each compound obtained in Example 1 and Comparative Examples 1 and 2 was made into a sodium salt using water and a 10% aqueous sodium carbonate solution, and the solubility of the sodium salt in water was evaluated. The evaluation criteria are as follows.
Solubility in water is 4% or more ...
Solubility in water is 1% or more and less than 4% ・ ・ ・ ・ ・ △
Solubility in water is less than 1% ・ ・ ・ ・ ・ ・ ・ ・ ・ ×

Table 1 Solubility test in water Example 1 ○
Comparative Example 1 ○
Comparative Example 2 ×

(B) Storage stability test The spectra of the solutions of Example 1 and Comparative Examples 1 and 2 obtained in the above "(A) Solubility test" were allowed to stand at 20 to 30 ° C. for 2 weeks before and after measurement. The dye residual rate was calculated by the following formula.
Dye residual rate (%) = (OD after test / OD before test) x 100
The evaluation criteria for the dye residual rate are as follows, and the larger the value, the better the storage stability.
Dye residual rate is 80% or more ...
Dye residual rate is less than 80% ・ ・ ・ ・ ・ ・ ・ ・ ・ ×

Table 2 Storage stability test Example 1 ○
Comparative Example 1 ×
Comparative example 2 ○

From the results of Tables 1 and 2, the diimonium compound of the present invention showed higher solubility in water and excellent storage stability as compared with the compounds of Comparative Examples 1 and 2.

By using the diimonium compound of the present invention, it is possible to provide an aqueous composition that does not contain heavy metals, has high water solubility, and has high storage stability as an aqueous solution.

Claims (2)

The following formula (1)

An aqueous composition containing a salt of a diimonium compound represented by (X represents an integer of 1 to 3 in the formula (1)) and an aqueous medium. The aqueous composition according to claim 1, wherein X in the formula (1) is 3.