JP2006143674A - Diimonium salt compound, and near-infrared absorber and near-infrared cut filter each containing the compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diimonium salt compound having a high solubility in an organic solvent or in a resin used in a near-infrared cut filter and being capable of forming a highly transparent film and to provide a near-infrared absorber and a near-infrared cut filter each containing the diimonium salt compound. <P>SOLUTION: What is provided is: a diimonium salt compound represented by formula (1) or (2); and a near-infrared absorber and a near-infrared cut filter each containing the diimonium salt compound. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a novel diimonium salt compound having absorption in the near infrared region, a near infrared absorber containing the compound, and a near infrared cut filter.

Recently, the sales volume of flat panel displays (FPD) has increased rapidly. Among them, the plasma display panel (PDP) has a feature that it has a bright screen and can respond to a quick movement of an image.
Since PDP uses plasma emission of rare gas, not only ultraviolet light necessary for fluorescence emission but also unnecessary electromagnetic waves and near infrared rays are generated. There are concerns about the effects of electromagnetic waves on the health of the human body, and near infrared rays have been pointed out to cause malfunctions by acting on remote control light receiving parts of home appliances. For this reason, measures such as cutting electromagnetic waves with a metal mesh or cutting near infrared rays with a near infrared cut filter are taken.

  Near-infrared cut filters are used for applications such as optical lenses, architectural window glass, and automotive window glass in addition to PDP applications, and require high transmittance in the visible region along with strong absorption in the near-infrared region.

Examples of near-infrared absorbing dyes disclosed so far for use in near-infrared cut filters include, for example, N, N, N ′, N′-tetrakis {p-di (n) disclosed in JP-A-10-180922. There is hexafluoroantimonate of -butyl) aminophenyl} -p-phenylenediimonium, which is problematic due to the toxicity of antimony.
JP-A-5-247437 discloses diimonium hexafluorophosphate, and WO 2004/048480 discloses diimonium perfluoroalkylsulfonimidate. However, all of these compounds have low solubility in organic solvents and resins, and it is difficult to produce a uniform resin solution. Therefore, it is difficult to produce a highly transparent filter.
JP 10-180922 A JP-A-5-247437 WO2004 / 048480

An object of the present invention is to provide a novel diimonium salt compound that has a high solubility in organic solvents and resins used in near infrared cut filters and the like, and that can form a highly transparent film with low visible light absorption. And a near-infrared absorber containing the same and a near-infrared cut filter.

［式（１）、（２）中、Ｒ^１、Ｒ^２はそれぞれ独立にアルキル基を示し、Ｘ、Ｙ、Ｚはそれぞれ独立に、パーフルオロアルキル基、アリール基、又は一般式（Ａ）：

（式（Ａ）において、環Ａは、それが結合している窒素原子及びカルボニル基と共に形成される複素環を表す）
で表される環構造の置換基を示す。但し、Ｘ、Ｙが同時にパーフルオロアルキル基となることはない。］
また、本願の第２の発明は上記ジイモニウム塩化合物を含有する近赤外線吸収剤である。更に、本願の第３の発明は上記ジイモニウム塩化合物を含有する近赤外線カットフィルターである。 As a result of diligent studies to solve the above-mentioned problems, the present inventors have found that the object can be achieved by a diimonium salt compound having a specific compound in the anion moiety, and have completed the present invention.
That is, the present invention is first a diimonium salt compound represented by the general formula (1) or (2).

[In the formulas (1) and (2), R ¹ and R ² each independently represents an alkyl group, and X, Y and Z each independently represent a perfluoroalkyl group, an aryl group, or the general formula (A):

(In formula (A), ring A represents a heterocycle formed with the nitrogen atom and carbonyl group to which it is attached).
The substituent of the ring structure represented by these is shown. However, X and Y do not simultaneously become a perfluoroalkyl group. ]
Moreover, 2nd invention of this application is a near-infrared absorber containing the said diimonium salt compound. Furthermore, the third invention of the present application is a near-infrared cut filter containing the diimonium salt compound.

  The diimonium salt compound of the present invention exhibits strong absorption at 900 to 1200 nm, has excellent properties that hardly shows absorption in the visible region, and is compatible with resins used in near infrared absorbers and near infrared cut filters. Since it is extremely high, there is no haze problem, and a highly transparent near-infrared cut filter can be obtained.

Detailed description of the invention

First, the diimonium salt compound of the present invention will be described below.
The diimonium salt compound of the present invention is represented by the following general formula (1) or (2).

［式（１）、（２）中、Ｒ^１、Ｒ^２はそれぞれ独立にアルキル基を示し、Ｘ、Ｙ、Ｚはそれぞれ独立に、パーフルオロアルキル基、アリール基、又は一般式（Ａ）：

（式（Ａ）において、環Ａは、それが結合している窒素原子及びカルボニル基と共に形成される複素環を表す）
で表される環構造の置換基を示す。但し、Ｘ、Ｙが同時にパーフルオロアルキル基となることはない。］

[In the formulas (1) and (2), R ¹ and R ² each independently represents an alkyl group, and X, Y and Z each independently represent a perfluoroalkyl group, an aryl group, or the general formula (A):

(In formula (A), ring A represents a heterocycle formed with the nitrogen atom and carbonyl group to which it is attached).
The substituent of the ring structure represented by these is shown. However, X and Y do not simultaneously become a perfluoroalkyl group. ]

R ¹ and R ² are each independently an alkyl group, among which a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. And an alkyl group having 1 to 6 carbon atoms such as n-pentyl group, isopentyl group, sec-pentyl group, tert-pentyl group and n-hexyl group. In particular, an ethyl group, an n-propyl group, and an n-butyl group are particularly preferable.

As what X, Y, and Z are perfluoroalkyl groups, C1-C4 perfluoroalkyl groups, such as a trifluoromethyl group, a pentafluoroethyl group, a heptafluoropropyl group, a nonafluorobutyl group, are preferable. X and Y do not simultaneously become a perfluoroalkyl group.

As X, Y, Z being an aryl group, as a substituent, an alkyl group having 1 to 4 carbon atoms, a halogen atom, an alkoxy group having 1 to 4 carbon atoms, a nitro group, or perfluoro having 1 to 4 carbon atoms. A phenyl group which may have an alkyl group is preferred. Examples include phenyl group, 4-methylphenyl group, 2,4,6-trimethylphenyl group, 4-chlorophenyl group, 4-bromophenyl group, 4-methoxyphenyl group, 4-nitrophenyl group, 3-nitrophenyl. Group, 2,4-dinitrophenyl group, 4-trifluoromethylphenyl group, 2-nitro-4-trifluoromethylphenyl group and the like. Among these, 4-methylphenyl group, 4-chlorophenyl group, 4-methoxyphenyl group, 4-nitrophenyl group, and 4-trifluoromethylphenyl group are particularly preferable.

で表される環構造の置換基であるものとしては、式（Ａ）中の窒素原子及びカルボニル基と共に、環構成成分として更に窒素原子、カルボニル基、酸素原子又は炭素数１〜４のアルキレン基を有する、４〜６員環の複素環であるのが好ましい。
これらの例としては、

が挙げられる。とりわけ、

が特に好適に用いられる。 X, Y, and Z are the general formula (A):

In addition to the nitrogen atom and carbonyl group in the formula (A), the ring component further includes a nitrogen atom, a carbonyl group, an oxygen atom, or an alkylene group having 1 to 4 carbon atoms. It is preferably a 4- to 6-membered heterocyclic ring having
Examples of these are:

Is mentioned. Above all,

Is particularly preferably used.

Table 1 below shows typical examples of the counter anion portion of the diimonium salt compound of the general formula (1) or (2).

As preferred specific examples of the diimonium salt compound of the general formula (1) or (2) of the present invention, the following compounds can be exemplified.

Next, the manufacturing method of the diimonium salt compound of this invention is demonstrated.
[Synthesis of sulfonimide acid]
General formula: XSO ₂ NHSO ₂ Y
(X and Y are the same as those in the general formula (1))
Is synthesized. The compound can be synthesized by the following method. The sulfonamide derivative XSO ₂ NH ₂ and the sulfonic acid chloride derivative YSO ₂ Cl are reacted in an approximately equimolar amount in a solvent at 0 to 60 ° C., preferably 20 to 40 ° C., for 10 to 48 hours, preferably 5 to 24 hours. Let Next, the product is discharged into water, and impurities are transferred to the water layer to obtain the target XSO ₂ NHSO ₂ Y. As the solvent, halogenated hydrocarbon, dimethylformamide (DMF), dimethylacetamide (DMAC), dimethylimidazolidinone (DMI) and the like can be used. In the case of halogenated hydrocarbon solvent, as a solution, DMF, DMAC When a solvent such as DMI is used, the target product is obtained as a precipitate.
General formula: XSO ₂ NHCOZ
(X and Z are the same as those in the general formula (2))
Can be synthesized by the following method. The sulfonamide derivative XSO ₂ NH ₂ and the carboxylic acid chloride derivative ZCOCl are mixed in a polar solvent such as DMF, DMAC, and DMI at 0 to 100 ° C., preferably 20 to 50 ° C., for 1 to 24 hours, preferably 1 to React for 4 hours. The reaction mixture is discharged into water, and the target product can be obtained as an oil or precipitate.

[Synthesis of Sulfonimidate Silver Salt]
Next, the silver salt of sulfonimidic acid is produced. The sulfonimide acid is dissolved in 5 to 100 times its weight of water and reacted at 20 to 100 ° C., preferably 50 to 70 ° C., for 1 to 10 hours, preferably 2 to 4 hours. By cooling to room temperature, removing insolubles by filtration, and evaporating water from the filtrate, a silver sulfonimidate of the following general formula (3) or (5) can be obtained.

[Synthesis of diimonium salt compounds]
The sulfonimidic acid silver salt represented by the general formula (3) or (5) and the N, N, N ′, N′-tetrakis (dialkylaminophenyl) phenylenediamine represented by the following general formula (4) Are reacted in a polar solvent such as DMF, DMAC, DMI at 20 to 120 ° C., preferably 70 to 100 ° C. for 1 to 20 hours, preferably 1 to 4 hours. Next, the precipitated silver is filtered off, water is added, and the resulting precipitate is filtered and dried to obtain the diimonium salt compound represented by the general formula (1) or (2).

［式（３）、（４）、（５）中、Ｘ、Ｙ、Ｚ、Ｒ^１、Ｒ^２は、式（１）、（２）におけるＸ、Ｙ、Ｚ、Ｒ^１、Ｒ^２と同じ意味を表す。］
尚、一般式（４）のＮ，Ｎ，Ｎ’，Ｎ’−テトラキス（ジアルキルアミノフェニル）フェニレンジアミンは、公知の化合物である。

[Equation (3), (4), in (5), X, Y, ^Z, R 1, ^{R 2} has the formula (1), the same X, Y, ^Z, and R 1, ^{R 2} in (2) Represents meaning. ]
In addition, N, N, N ′, N′-tetrakis (dialkylaminophenyl) phenylenediamine of the general formula (4) is a known compound.

[Near infrared absorber]
The near-infrared absorber of the present invention may be the diimonium salt compound itself of the present invention, or a composition obtained by adding a binder resin or the like to the compound.
The binder resin is not particularly limited. For example, homopolymers or copolymers of acrylic monomers such as acrylic acid, methacrylic acid, acrylic ester, and methacrylic ester, methyl cellulose, ethyl cellulose, and cellulose acetate are used. Cellulose polymers, polystyrene, vinyl chloride-vinyl acetate copolymers, polyvinyl pyrrolidone, polyvinyl butyral, vinyl polymers such as polyvinyl alcohol and vinyl compound copolymers, condensation polymers such as polyester and polyamide, butadiene-styrene Examples thereof include a rubber-based thermoplastic polymer such as a copolymer, and a polymer obtained by polymerizing and crosslinking a photopolymerization compound such as an epoxy compound.

(Manufacture of near-infrared cut filter)
As a method for producing a near infrared cut filter using the diimonium salt compound of the present invention, there are a casting method and a melt extrusion method.

A. Casting method It is obtained by dissolving a resin or resin monomer and the diimonium salt compound of the present invention in an organic solvent, and applying and drying on a transparent film, panel or glass substrate.
As the organic solvent, halogen-based, alcohol-based, ketone-based, ester-based, aliphatic hydrocarbon-based, ether solvent, or a mixture thereof is used.
Examples of the resin or resin monomer used include fatty acid ester resins, acrylic resins, melamine resins, urethane resins, aromatic ester resins, polycarbonate resins, aliphatic polyolefin resins, polyvinyl resins, polyvinyl alcohol resins, polyvinyl modified resins, etc. These resins or their monomers or their copolymer resins are used.
The amount of dimonium salt compound used varies depending on its extinction coefficient, the thickness of the filter substrate or film to be produced, the desired absorption strength, the desired transmission characteristics, the transmittance, etc. 1 ppm to 20% by weight.

B. Melt Extrusion Method The diimonium salt compound of the present invention is added to a base resin powder or pellet, heated and melted at 150 to 350 ° C., and then molded to produce a plate or formed into a film with an extruder.
The resin used in the melt extrusion method is preferably as highly transparent as possible when a plate or film is produced. Specifically, polyethylene terephthalate, polyethersulfone, polyethylene naphthalate, polyarylate, polyetherketone, Polycarbonate, Polyamide such as Polyethylene, Polypropylene and Nylon 6, Cellulose resin such as Polyimide and Triacetylcellulose, Fluorine resin such as Polyurethane and Polytetrafluoroethylene, Vinyl compound such as polyvinyl chloride, Polyacrylic acid, Polyacrylic ester , Polyacrylonitrile, addition polymers of vinyl compounds, polymethacrylic acid, polymethacrylates, vinylidene compounds such as polyvinylidene chloride, vinylidene fluoride / trifluoroethylene copolymers, Copolymers of alkylene / vinyl compounds vinyl acetate copolymer, or fluorine compounds, polyethers such as polyethylene oxide, epoxy resins, polyvinyl alcohol, and polyvinyl butyral.

The processing method varies slightly depending on the dimonium salt compound and base resin used, but the dimonium salt compound is added to the base resin powder or pellets and heated, melted, and kneaded at 150 to 350 ° C. After that, a method of forming a plate by molding, a method of forming a film with an extruder, an original plate with an extruder, stretched uniaxially or biaxially 2 to 5 times at 30 to 120 ° C., 10 And a method of forming a film having a thickness of ˜200 μm.
In addition, you may add the additive used for normal resin molding, such as a plasticizer, at the time of kneading | mixing. The addition amount of the dimonium salt compound varies depending on the absorption coefficient, the thickness of the resin molded body to be produced, the target absorption strength, the target transmission characteristics / transmittance, etc., but is usually 1 ppm to 20 relative to the weight of the base resin molded body. % By weight, preferably 1 ppm to 10% by weight, particularly preferably 1 ppm to 5% by weight.

  When the near infrared cut filter of the present invention is used as a PDP filter, it is preferable to provide an electromagnetic wave shielding function. For the electromagnetic wave shield, a laminate using a silver thin film or a metal mesh mainly using copper can be used. A laminate using a silver thin film is preferably one in which a dielectric such as indium oxide, zinc oxide and titanium oxide and silver are alternately formed into five layers. The number of laminated layers is preferably 5 to 9, but is not limited to this total number, and in order to increase adhesion and durability, an ultra-thin film that does not hinder optical properties between the dielectric and silver is used. It may be inserted. As the metal mesh, a fiber mesh obtained by vapor-depositing a metal on a fiber, an etching mesh that forms a pattern by etching using a photolithography technique, and the like can be used.

  EXAMPLES The present invention will be described more specifically with reference to the following examples, but the present invention is not limited thereto.

[Production Example 1] Synthesis of N-trifluoromethylsulfonyl-N- (2-oxazolidone) sulfonyliminate silver salt 19.81 g of chlorosulfonyl isocyanate was dissolved in 50 ml of methylene chloride and cooled to 5 ° C or lower. To this, 19.24 g of 2-bromoethanol dissolved in 50 ml of methylene chloride was added dropwise over 40 minutes. After dripping, it was made to react at 10 degrees C or less for 60 minutes. The reaction mixture was added dropwise to a mixture of 20.87 g of trifluoromethanesulfonamide, 29.74 g of triethylamine and 50 ml of methylene chloride at a temperature below 0 ° C. over 65 minutes. The cooling bath was removed and the reaction was allowed to proceed at room temperature (28 ° C.) for 25 hours. The contents were discharged into 200 ml of water, and the methylene chloride layer was separated by liquid separation, washed with water, and concentrated to obtain 27.47 g of orange oil. It was confirmed by mass spectrometry (M / e = 298) that it was N-trifluoromethylsulfonyl-N- (2-oxazolidone) sulfonyliminate.
7.1 g of the obtained orange oil was dissolved in 60 ml of water, and 4.5 g of silver oxide was added thereto and reacted at 60 ° C. for 4 hours. The mixture was cooled to room temperature, insoluble matters were removed by filtration, and the filtrate was subjected to water removal with an evaporator to obtain 9.35 g of a white powder. It was confirmed by infrared absorption spectrum and fluorescent X-ray analysis that it was the objective N-trifluoromethylsulfonyl-N- (2-oxazolidone) sulfonyliminate silver salt.

[Production Example 2] Synthesis of bis (p-toluenesulfonyl) iminate silver salt 11.6 g of paratoluenesulfonamide sodium salt was dissolved in 150 ml of dimethylformamide, and 11.4 g of paratoluenesulfonyl chloride was dissolved in dimethylformamide. A solution dissolved in 30 ml was added dropwise at room temperature. The mixture was reacted at 100 ° C. for 3 hours and allowed to cool to room temperature. The reaction mixture was discharged into 600 ml of 3.5% hydrochloric acid. The resulting white precipitate was collected by filtration and dried to obtain 10.8 g of a white powder. The melting point was 133-135 ° C. From mass spectrometry (M / e = 226) and infrared absorption spectrum, this was identified as bis (p-toluenesulfonyl) iminic acid.
A silver salt of this product was obtained in the same manner as in Production Example 1.

[Production Example 3] Synthesis of N-trifluoromethylcarbonyl-N- (p-toluenesulfonyl) iminate silver salt 5.00 g of paratoluenesulfonamide was dissolved in 25 ml of dimethylimidazolidinone, and trifluoroacetic anhydride was added thereto. 9.20 g was added dropwise at room temperature for 30 minutes. After reacting at room temperature for 1 hour, it was discharged into 25 ml of n-heptane. The resulting white precipitate was collected by filtration, washed with 25 ml of n-heptane, and then dried to obtain 6.97 g of a white powder. It was confirmed to be N-trifluoromethylcarbonyl-N- (p-toluenesulfonyl) iminic acid by infrared absorption spectrum and mass spectrometry (M / e = 267).
A silver salt of this product was obtained in the same manner as in Production Example 1.

Example 1 Synthesis of Specific Example Compound 1 To 10 ml of DMF, 2.10 g of N-trifluoromethylsulfonyl-N- (2-oxazolidone) sulfonyliminate silver salt (Production Example 1) and N, N, N ′, After adding 0.40 g of N′-tetrakis {4-di (n-butylaminophenyl)}-p-phenylenediamine and reacting at 60 ° C. for 3 hours, the produced silver was separated by filtration. The filtrate was discharged into 20 ml of water, and the aqueous layer was removed by decantation. The remaining viscous material was crystallized by adding heptane to obtain 0.51 g of a dark brown powder. The melting point was 118-122 ° C.
From the elemental analysis values, IR spectrum, etc., it was confirmed to be the target compound.
Elemental analysis _{(as C 70 H 100 N 10 F 6} O 12 S 4)
C (%) H (%) N (%)
Theoretical 55.47 6.65 9.24
Found 55.52 6.63 9.19
The absorption maximum wavelength of the obtained compound in a methanol solution was 1065 nm, and the gram extinction coefficient was 55300 ml / g · cm. An absorption spectrum chart of this compound in a methanol solution is shown in FIG. 1, and an infrared absorption spectrum chart is shown in FIG.

Example 2 Synthesis of Specific Example Compound 2 In 50 ml of DMF, 588 mg of bis (p-toluenesulfonyl) iminate silver salt (Production Example 2) and N, N, N ′, N′-tetrakis {4-di (n -Butylaminophenyl)}-p-phenylenediamine (317 mg) was added, and the mixture was reacted at room temperature for 35 minutes. The filtrate was discharged into 100 ml of water, and the aqueous layer was removed by decantation. When 10 ml of methanol was added to the residue and stirred, a precipitate was formed. This precipitate was filtered and dried to obtain 64 mg of a green powder. The melting point was 160-170 ° C. (with decomposition).
From the elemental analysis values, IR spectrum, etc., it was confirmed to be the target compound.
Elemental analysis _{(as C 90 H 120 N 8 O 8} S 4)
C (%) H (%) N (%)
Theoretical value 57.89 6.48 6.00
Measured value 57.95 6.43 5.92
The absorption maximum wavelength of the obtained compound in a methanol solution was 1065 nm, and the gram extinction coefficient was 54900 ml / g · cm. An absorption spectrum chart of this compound in a methanol solution is shown in FIG. 2, and an infrared absorption spectrum chart is shown in FIG.

Example 3 Synthesis of Specific Example Compound 3 To 50 ml of DMF, 334 mg of N-trifluoromethylcarbonyl-N- (p-toluenesulfonyl) iminate silver salt (Production Example 3) and N, N, N ′, N ′ -Tetrakis {4-di (n-butylaminophenyl)}-p-phenylenediamine (230 mg) was added, and the mixture was reacted at room temperature for 4 hours. The filtrate was drained into 100 ml of water. The precipitate was collected by filtration and dried to obtain 59 mg of a gray powder. The melting point was 61-84 ° C. (with decomposition).
From the elemental analysis values, IR spectrum, etc., it was confirmed to be the target compound.
Elemental analysis _{(as C 80 H 106 F 6 N 8} O 6 S 2)
C (%) H (%) N (%)
Theoretical 66.09 7.35 7.71
Actual value 66.23 7.39 7.58
The absorption maximum wavelength of the obtained compound in a methanol solution was 1065 nm, and the gram extinction coefficient was 70500 ml / g · cm. An absorption spectrum chart of this compound in a methanol solution is shown in FIG.

[Example 4] Manufacture of near-infrared absorber Delpet 80N (manufactured by Asahi Kasei Kogyo Co., Ltd .: acrylic resin) as a binder and 0.2 g (specific example compound 1) obtained in Example 1 of the present invention. Is dissolved in 90 g of a mixed solvent of toluene / methyl ethyl ketone / methanol (1/1 / 0.1), and this solution is dried with a wire bar so that the film thickness after drying is about 5 μm. PET) film was applied to obtain a sample of near infrared absorber.
Laser light of a single mode semiconductor laser (wavelength: 830 nm) was collected on the surface of the sample with a lens and arranged so that the beam diameter was 10 μm on the surface of the sample. The semiconductor laser was adjusted so that the power of the laser reaching the surface could be changed in the range of 50 to 200 mW, and the sample was irradiated with a single pulse with a pulse width of 20 μs. When the sample was observed with an optical microscope after irradiation, formation of a through-hole having a diameter of about 10 μm was observed when the laser power reaching the surface was 50 mW, and it was confirmed that this sample had near-infrared absorption ability.

[Example 5] Production of near-infrared cut filter The compound (specific example compound 1) obtained in Example 1 was dissolved in toluene so as to have a concentration of 1000 ppm. This solution and acrylic adhesive are mixed at a ratio of 20: 80% by weight, coated on a polyethylene terephthalate film (Teijin Limited, thickness 75 μm) with a batch die coater, dried, and cut with near infrared rays. A filter was produced. The dry film thickness of the coating layer was 25 μm.
About this filter, the transmittance | permeability was measured in Hitachi self-recording spectrophotometer U-3500. The transmission spectrum of this filter is shown in FIG.

[Example 6]
In Example 5, except that the specific example compound 2 was used instead of the specific example compound 1, the same operation as in the example 5 was performed to prepare a near infrared cut filter.
About this filter, the transmittance | permeability was measured in Hitachi self-recording spectrophotometer U-3500. The transmission spectrum of this filter is shown in FIG.

[Example 7]
In Example 5, except that the specific example compound 3 was used in place of the specific example compound 1, the same operation as in Example 5 was performed to prepare a near infrared cut filter.
About this filter, the transmittance | permeability was measured in Hitachi self-recording spectrophotometer U-3500. The transmission spectrum of this filter is shown in FIG.

[Comparative Example 1]
Instead of the specific example compound 1 obtained in Example 1, bis {bis (trifluoromethanesulfone) imidic acid} -N, N, N ′, N′-tetrakis {4-di (n-butylaminophenyl)}-p An attempt was made to disperse and dissolve -phenylene dimonium (synthesized by the same operation method as in Example 1 of WO 2004/048480) in toluene to a concentration of 1000 ppm, but it was not completely dissolved. An acrylic adhesive was added to the toluene suspension, but the imonium salt compound was not completely dissolved, and a transparent near-infrared cut filter could not be produced. Therefore, the operation was stopped.

[Comparative Example 2]
Instead of the specific example compound 1 obtained in Example 1, hexafluoroantimonic acid-N, N, N ′, N′-tetrakis {4-di (n-butylaminophenyl)}-p-phenylenediimonium was added in toluene. An attempt was made to disperse and dissolve so that the concentration was 1000 ppm, but it was not completely dissolved. An acrylic adhesive was added to the toluene suspension, but the imonium salt compound was not completely dissolved, and a transparent near-infrared cut filter could not be produced. Therefore, the operation was stopped.

[Industrial applicability]
The diimonium salt compound of the present invention has little absorption in the visible part and high solubility in organic solvents and resins. Moreover, since it does not contain heavy metals, there are no environmental problems.
The near-infrared cut filter of the present invention containing the diimonium salt compound of the present invention can be used for various applications. For example, it is suitable as a near-infrared cut filter for PDP, building material glass, and a near-infrared cut filter for automobile window glass.

FIG. 4 is an absorption spectrum diagram of Compound 1 synthesized in Example 1. FIG. 5 is an absorption spectrum diagram of Compound 2 synthesized in Example 2. FIG. 4 is an absorption spectrum diagram of Compound 3 synthesized in Example 3. FIG. 6 is a transmission spectrum diagram of the filter produced in Example 5. FIG. 6 is a transmission spectrum diagram of the filter produced in Example 6. FIG. 5 is a transmission spectrum diagram of the filter produced in Example 7. FIG. 4 is an infrared absorption spectrum diagram of Compound 1 synthesized in Example 1. FIG. 5 is an infrared absorption spectrum diagram of Compound 2 synthesized in Example 2.

Claims (5)

A diimonium salt compound represented by the general formula (1) or (2).

[In the formulas (1) and (2), R ¹ and R ² each independently represents an alkyl group, and X, Y and Z each independently represent a perfluoroalkyl group, an aryl group, or the general formula (A):

(In formula (A), ring A represents a heterocycle formed with the nitrogen atom and carbonyl group to which it is attached).
The substituent of the ring structure represented by these is shown. However, X and Y do not simultaneously become a perfluoroalkyl group. ] The diimonium salt compound according to claim ¹ , wherein R ¹ and R ² are each independently an alkyl group having 1 to 6 carbon atoms. X, Y and Z are each independently a C 1-4 perfluoroalkyl group; a C 1-4 alkyl group, a halogen atom, a C 1-4 alkoxy group, a nitro group or a carbon number as a substituent. A phenyl group optionally having 1 to 4 perfluoroalkyl groups; or the general formula (A):

[In Formula (A), represents a 4- to 6-membered heterocyclic ring having a nitrogen atom, a carbonyl group, an oxygen atom or an alkylene group having 1 to 4 carbon atoms as a ring component together with a nitrogen atom and a carbonyl group]
The diimonium salt compound according to claim 1, wherein the diimonium salt compound is a substituent having a ring structure represented by the formula: The near-infrared absorber containing the diimonium salt compound in any one of Claims 1-3. The near-infrared cut filter containing the diimonium salt compound in any one of Claims 1-3.

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