JP2007297333A - Diimmonium salt compound, near-infrared ray-absorbing composition containing the same, near-infrared ray-absorbing filter and front panel for display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a near-infrared ray-absorbing compound (diimmonium salt compound) excellent in heat resistance and moisture resistance, and to provide a near-infrared ray-absorbing composition including the same, a near-infrared ray-absorbing filter and a front panel for display. <P>SOLUTION: The invention relates to the diimmonium salt compound having a structure represented by formula (1). In the formula (1), at least one of R<SB>1</SB>-R<SB>8</SB>is an isoamyl group, X is an anion exhibited by (RfSO<SB>2</SB>)-N<SP>-</SP>-(SO<SB>2</SB>Rf'), (Rf and Rf' are each a 1-4C fluoroalkyl group). At least one of the ring A and ring B optionally has a substituent. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a diimonium salt compound used in the production of a near-infrared filter and the like, a near-infrared absorbing composition containing the same, a near-infrared absorbing filter, and a display front plate.

  In recent years, various types of displays have been developed and commercialized as large displays, and one of them is a plasma display. In a display panel constituting a plasma display (referred to as a plasma display panel, hereinafter abbreviated as “PDP”), a mixed gas containing xenon and neon is enclosed between two glass plates. When a high voltage is applied to the mixed gas, ultraviolet rays are generated, and the phosphors emit light when the ultraviolet rays are applied to the glass plate.

During the discharge, near infrared rays having a wavelength of 850 nm to 1100 nm are also emitted simultaneously with ultraviolet rays. Since the near infrared wavelength region overlaps with the near infrared communication or remote control wavelength region of home electronic devices, the near infrared rays emitted from the PDP cause malfunction of the electronic device. Therefore, near infrared rays are conventionally absorbed using the near infrared ray absorption filter containing the diimonium salt compound which has near infrared ray absorption ability in the front plate of PDP (for example, refer patent document 1).
Japanese Examined Patent Publication No. 6-26028

  In conventional near-infrared absorption filters, a compound having a linear alkyl group as a terminal group is often used as the diimonium salt compound. However, the near-infrared absorption filter using these compounds has a problem that the near-infrared absorption ability is lowered due to the reason that the above-mentioned compounds are easily deteriorated with respect to humidity. Furthermore, the above-mentioned modified compound has a problem in that it absorbs light in the visible region and the color of the filter itself changes.

  The present invention relates to a near-infrared absorbing compound (diimonium salt compound) that is more excellent in heat and moisture resistance than a diimonium salt compound having a linear alkyl group, a near-infrared absorbing composition containing the same, and a near-infrared absorbing filter Provide a front plate for display.

  The diimonium salt compound of the present invention is characterized by having a structure represented by the following formula (1).

However, in formula (1), at least one of R _{1 to} R ₈ is an isoamyl group, and X is (R _f SO ₂ ) —N ⁻ — (SO ₂ R _f ′) (R _f and R _f 'is an anion represented by fluoroalkyl groups) of 1 to 4 carbon atoms. At least one of ring A and ring B may have a substituent.

  The near-infrared absorbing composition of the present invention comprises at least one diimonium salt compound of the present invention and a resin.

  The near-infrared absorption filter of the present invention includes at least one diimonium salt compound having the structure represented by the above (1).

  The display front plate of the present invention includes the near-infrared absorbing filter of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the near-infrared absorption compound (diimonium salt compound) excellent in heat-and-moisture resistance, the near-infrared absorption composition containing this, a near-infrared absorption filter, and the display front board can be provided.

  Hereinafter, the present invention will be described in detail.

(Embodiment 1)
In Embodiment 1, the diimonium salt compound of the present invention will be described. The diimonium salt compound of the present invention has a structure represented by the above formula (1).

In the formula (1), X is an anion necessary for neutralizing the charge, and (R _f SO ₂ ) —N ⁻ — (SO ₂ R _f ′) (R _f and R _f ′ are carbon atoms of 1 -4 fluoroalkyl groups). Specifically, for example, bis (trifluoromethanesulfone) imide acid ion, bis (pentafluoroethanesulfone) imide acid ion, pentafluoroethanesulfone trifluoromethanesulfonimide acid ion, trifluoromethanesulfone heptafluoropropanesulfonimide acid ion And anions such as nonafluorobutanesulfone trifluoromethanesulfonimidate ion. Of these, bis (trifluoromethanesulfone) imidic acid ions, bis (pentafluoroethanesulfone) imidic acid ions, and the like, in which R _f and R _f ′ are the same perfluoroalkyl group, are preferable in terms of high near infrared absorption ability. .

  At least one of ring A and ring B may have 1 to 4 substituents other than the 1,4-position, or may not have a substituent. Examples of the substituent include at least one substituent selected from the group consisting of a lower alkyl group, a lower alkoxy group, a cyano group, a halogen atom, and a hydroxyl group. As a lower alkyl group, a C1-C5 alkyl group, such as a methyl group and an ethyl group, is mentioned, for example. As a lower alkoxy group, C1-C5 alkoxy groups, such as a methoxy group and an ethoxy group, are mentioned, for example. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

  When at least one of the ring A and the four rings B has a substituent, the substituent is preferably a halogen atom (especially a chlorine atom or a bromine atom), a methyl group, or a cyano group.

  When all four rings B have a substituent, it is preferable that all the substituents are the same. In this case, the position of the substituent is preferably m-position with respect to the nitrogen atom bonded to the phenylenediamine skeleton, since it is easy to synthesize.

  It is more preferable in the synthesis of the diimonium salt compound that the ring A and the four rings B have no substituent other than the 1,4-position.

All of R _{1 to} R ₈ may be the isoamyl group, but some of R _{1 to} R ₈ are the isoamyl groups, and the rest are, for example, branched or linear. It may be an alkyl group. The number of carbon atoms of the branched or straight chain alkyl group is suitably 1-20. Furthermore, the branched or straight chain alkyl group may have a substituent or may not have a substituent.

  Examples of the branched alkyl group include 1-methylethyl group (iso-propyl group), 1-methylpropyl group (sec-butyl), 1,1-dimethylethyl group (t-butyl group), 1, 1-dimethylpropyl group, 1-methylbutyl group, 1,2-dimethylpropyl group, 1,2-dimethylbutyl group, 2-methylpropyl group (iso-butyl group), 2,2-dimethylpropyl group, 2-methylbutyl Group having 1 to 20 carbon atoms such as 2-ethylbutyl group, 3-methylbutyl group (iso-amyl group), 1,1-dimethylbutyl group, 2,2-dimethylbutyl group, and 3,3-dimethylbutyl group. A branched alkyl group is exemplified. Of these, a branched alkyl group having 1 to 10 carbon atoms is preferable.

  As said linear alkyl group, an ethyl group, n-propyl group, or n-butyl group etc. are mentioned, for example.

  When these branched alkyl groups or linear alkyl groups have a substituent, the substituent is a cyano group, a hydroxyl group, a halogen atom, an alkoxyalkoxy group having 2 to 8 carbon atoms, an alkoxy having 3 to 15 carbon atoms. Examples thereof include an alkoxyalkoxy group, an aryloxy group having 6 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 7 carbon atoms, an alkylcarbonyloxy group having 2 to 7 carbon atoms, and an alkoxycarbonyloxy group having 2 to 7 carbon atoms.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, and a bromine atom. Examples of the alkoxyalkoxy group having 2 to 8 carbon atoms include methoxymethoxy group, ethoxymethoxy group, methoxyethoxy group, ethoxyethoxy group, methoxypropoxy group, methoxybutoxy group, and ethoxybutoxy group.

  Examples of the alkoxyalkoxyalkoxy group having 3 to 15 carbon atoms include a methoxymethoxymethoxy group, a methoxymethoxyethoxy group, a methoxyethoxyethoxy group, and an ethoxyethoxyethoxy group.

  Examples of the aryloxy group having 6 to 12 carbon atoms include a phenoxy group, a tolyloxy group, a xylyloxy group, and a naphthyloxy group.

  Examples of the alkoxycarbonyl group having 2 to 7 carbon atoms include a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an isopropoxycarbonyl group, and an n-butoxycarbonyl group.

  Examples of the alkylcarbonyloxy group having 2 to 7 carbon atoms include a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, and an n-butylcarbonyloxy group.

  Examples of the alkoxycarbonyloxy group having 2 to 7 carbon atoms include a methoxycarbonyloxy group, an ethoxycarbonyloxy group, an n-propoxycarbonyloxy group, and an n-butoxycarbonyloxy group.

  Next, specific examples of the diimonium salt compound of the present invention are shown in Table 1.

In Table 1, when other than the 1,4-position of ring A is unsubstituted, it is abbreviated as “H”, and the same applies to ring B. When all of R _{1 to} R ₈ are isoamyl groups, they are abbreviated as 8 (isoamyl). When any four of R _{1 to} R ₈ are isoamyl groups and the remaining four are n-butyl groups, they are abbreviated as 4 (isoamyl) and 4 (n-butyl).

  The diimonium salt compound represented by the formula (1) of the present invention can be produced, for example, by the following method.

  First, for example, an amino compound is obtained by a method described in US Pat. No. 3,251,881, US Pat. No. 3,575,871, Japanese Patent Application Laid-Open No. 61-69991, and the like. That is, first, as described in [Chemical Formula 2], p-phenylenediamine and 1-chloro-4-nitrobenzene are subjected to an Ullmann reaction and a reduction reaction to obtain an amino form. In [Chemical Formula 2], ring A and ring B are as defined above.

Next, for example, No. 1 in Table 1 above. In the case of obtaining a compound in which all the substituents of R _{1 to} R ₈ are the same as the compound (1) (all the same substituents), the organic solvent at 30 to 180 ° C., more preferably 50 to 150 ° C. The amino compound is dissolved, and 8 mol of a halogenated compound (1-bromo-3-methylbutane) is reacted with 1 mol of the amino compound in an organic solvent. Thereby, all the same substitution products can be obtained. As the organic solvent, a water-soluble polar solvent such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone is preferably used.

When synthesizing a compound other than all the same substitutes, for example, No. In the case of synthesizing compound 2, the amino compound is dissolved in a water-soluble polar solvent at 30 to 180 ° C., more preferably 50 to 150 ° C. Mole 1-bromo-3-methylbutane is reacted. In this way, an isoamyl group is introduced as four substituents among R _{1 to} R ₈ . Next, in order to introduce another substituent, 4 moles of 1-bromobutane are reacted with 1 mole of the amino compound in a solvent to obtain the remaining four substituents of R _{1 to} R ₈ as follows. n-Butyl is introduced. In the same manner as described above, any compound other than all the same substituents can be obtained.

  Next, the compound synthesized as described above is added to an organic solvent at 0 to 100 ° C., more preferably 20 to 100 ° C., together with an oxidizing agent (for example, a silver salt) corresponding to X in formula (1), Perform an oxidation reaction. As the organic solvent, a water-soluble polar solvent such as tetrahydrofuran, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone or the like is preferably used. When the equivalent of the oxidizing agent is 2 equivalents, the diimonium salt compound represented by the formula (1) is obtained.

  In addition to the method of reacting with the silver salt, the diimonium salt compound represented by the formula (1) can also be obtained by the following method.

  For example, oxidation of silver nitrate, silver perchlorate, cupric chloride, manganese dioxide, etc. in an organic solvent with the compound synthesized as described above (all the same substituted compounds or any compound other than all the same substituted compounds) Oxidize with agent. Salt exchange is performed by adding an acid or salt of a desired anion or an alkali of a desired cation to the obtained reaction solution. A diimonium salt compound can also be obtained by this method.

  The dimonium salt compound thus obtained has a maximum absorption wavelength of 900 nm or more, and an absorption coefficient as large as several tens of thousands to several hundreds of thousands. In addition to the use as a near-infrared absorbing compound contained in the near-infrared absorbing filter, such a compound is used as an anti-fading agent (singlet oxygen quencher) for optical recording media such as CD-R and DVD-R, a heat insulating film, Can be used for sunglasses.

(Embodiment 2)
In Embodiment 2, an example of a near-infrared absorption filter using the diimonium salt compound of Embodiment 1 will be described.

  As shown in FIG. 1, the near-infrared absorbing film of the present embodiment includes a base 1 and a near-infrared absorbing layer 2 disposed on one main surface of the base 1.

  The material of the base material 1 is not particularly limited as long as it is a material having translucency with respect to visible light. For example, a resin such as a saturated polyester resin, a polycarbonate resin, a polyacrylate resin, an alicyclic polyolefin resin, a polystyrene resin, a polyvinyl chloride resin, or a polyvinyl acetate resin is formed into a film or sheet. What was processed can be used.

  Examples of methods for processing the resin into a film or sheet include extrusion molding, calender molding, compression molding, injection molding, and a method in which the resin is dissolved in a solvent and cast. The thickness of the base material 1 is usually about 10 μm to 500 μm. Note that additives such as an antioxidant, a flame retardant, a heat resistance inhibitor, an ultraviolet absorber, a surface conditioner, a lubricant, and an antistatic agent may be added to the resin.

  The near-infrared absorbing layer 2 can be formed by applying a paint obtained by adding a near-infrared absorbing composition containing the near-infrared absorbing compound of Embodiment 1 and a resin as a binder to a solvent to a substrate. .

  The near-infrared absorbing compound contained in the near-infrared absorbing composition may be only the near-infrared absorbing compound (diimonium salt compound) of Embodiment 1, but another near-infrared absorbing compound of Embodiment 1 having a different maximum absorption wavelength. It preferably contains an infrared absorbing compound. As described above, when two or more kinds of near-infrared absorbing compounds having different maximum absorption wavelengths are used, it is wider in the near-infrared wavelength region (850 to 1100 nm) than when one kind of near-infrared absorbing compound is used. This is because light in the wavelength range can be absorbed. It is more preferable that the near-infrared absorbing composition contains two or more kinds of near-infrared absorbing compounds having different maximum absorption wavelengths so that almost all the light in the near-infrared wavelength region (850 to 1100 nm) can be absorbed. What is necessary is just to determine suitably the mixture ratio of 2 or more types of near-infrared absorption compounds according to the near-infrared absorption wavelength area | region etc. of each near-infrared absorption compound.

  Other near-infrared absorbing compounds having different maximum absorption wavelengths from the near-infrared absorbing compound of Embodiment 1 include cyanine dyes (ion binding compounds), phthalocyanine dyes (metal complex compounds), azo dyes, squarylium dyes And at least one dye selected from the group consisting of dithiol dyes.

  Examples of the combination of two or more near-infrared absorbing compounds include the diimonium compound / cyanine dye of Embodiment 1 and the diimonium salt compound / phthalocyanine dye of Embodiment 1.

  The binder resin contained in the near-infrared absorbing composition is not particularly limited as long as it has translucency for visible light, but acrylic resin, polyurethane resin, polyvinyl chloride resin, epoxy resin, polyacetic acid Vinyl resin, polystyrene resin, cellulose resin, polybutyral resin, polyester resin, or the like can be used. One of these resins may be used, or a polymer blend in which two or more are blended may be used. In particular, it is preferable to use a resin having a glass transition temperature of 80 ° C. or higher because the compatibility with the near-infrared absorbing compound is good.

  Although there is no restriction | limiting in particular about the mixture ratio of the binder resin contained in a near-infrared absorption composition, It is preferable in binder resin being about 1000-2000 weight part with respect to 100 weight part of near-infrared absorption compounds.

  If necessary, additives such as an antioxidant, a flame retardant, a heat resistance inhibitor, an ultraviolet absorber, a surface conditioner, a lubricant, and an antistatic agent may be added to the near-infrared absorbing composition.

  The solvent that is contained in the paint and dissolves the near-infrared absorbing compound and the binder resin is not particularly limited, but an organic solvent such as methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, tetrahydrofuran, acetonitrile, propionitrile, or these solvents. A mixed solvent is mentioned.

  In the present application, “dissolution of the near-infrared absorbing compound” means that the near-infrared absorbing compound dissolves in the solvent, does not have a solid shape, and becomes an ion pair or a complex state. It is distinguished from “dissociation”, which means a state in which it is dissolved in a solvent so as not to form a complex.

  There are no particular restrictions on the coating method, but for example, coating methods such as roll coating, die coating, air knife coating, blade coating, spin coating, reverse coating, gravure coating, gravure printing, screen printing, offset printing, inkjet printing, etc. The printing method can be used.

  The near-infrared absorption filter of the present embodiment preferably has a Haze value (defined in JIS K7105) of 1% or less. This is because, when the Haze value is 1 or less, for example, when the near-infrared absorption filter is used as a constituent member of the front plate of the PDP, the vividness of the image is not impaired. The Haze value is also called a haze value, and is a value representing the degree of haze inside or on the surface of the plastic. The lower the value, the better.

  The spectral transmittance of the near infrared absorption filter in the wavelength region of 850 nm to 1100 nm is preferably 15% or less, and more preferably 10% or less. If the spectral transmittance is within this range, the malfunction of the electronic device can be sufficiently suppressed by the near infrared absorption filter. The spectral transmittance is preferably as low as possible.

  The thickness of the near infrared absorption layer 2 is preferably 2 μm or more and 15 μm or less, and more preferably 3 μm or more and 10 μm or less. When the thickness of the near-infrared absorbing layer 2 is less than 2 μm, it is necessary to increase the amount of the near-infrared absorbing compound added to the binder resin in order to make the spectral transmittance in the wavelength region 850 nm to 1100 nm 15% or less. In this case, light scattering due to the undissolved near-infrared absorbing compound may occur, resulting in a problem that the haze value increases. Moreover, when the thickness of the near-infrared absorbing layer 2 exceeds 15 μm, the spectral transmittance in the wavelength region 850 nm to 1100 nm can be maintained at 15% or less, but a free solvent may remain in the near-infrared absorbing layer 2. . This residual solvent causes redissolution or dissociation of the near-infrared absorbing compound and causes deterioration of the near-infrared absorption characteristics over time. It is preferable that the near-infrared absorbing layer 2 has a thickness of 2 μm or more and 15 μm or less because these problems do not occur.

  The example of the near infrared absorption filter of the present embodiment has been described above by taking the near infrared absorption filter shown in FIG. 1 as an example, but the structure of the near infrared absorption filter of the present embodiment is limited to the example shown in FIG. Not. The near-infrared absorbing filter of this embodiment may be composed of a single layer in which a near-infrared absorbing compound is dispersed in a resin. Moreover, as shown in FIG. 2, the near-infrared absorption filter may be provided with the antireflection layer 4 arrange | positioned on the opposite side of the main surface by the side of the near-infrared absorption layer 2 of the base material 1, or the base material 1 And a hard coat layer 3 disposed between the antireflection layers 4. The hard coat layer 3 includes, for example, a thermosetting resin or inorganic fine particles. The antireflection layer 4 may be composed of three films having different refractive indexes. In this case, the three films are a medium refractive index film 4a, a high refractive index film 4b, and a low refractive index from the hard coat layer 3 side. The films 4c are arranged in this order.

(Embodiment 3)
In Embodiment 3, an example of the display front plate of the present invention will be described. As shown in FIG. 3, the display front plate 11 of the present embodiment includes a substrate 12, a near-infrared absorption filter 13 disposed on one main surface side of the substrate 12, and the other main surface side of the substrate 12. The electromagnetic wave shielding layer 14 and the electrode (earth) 15 are arranged.

  The material of the substrate 12 is not particularly limited as long as it is a material that transmits light with respect to visible light. For example, tempered glass or the like can be used. As the near-infrared absorption filter 13, for example, the near-infrared absorption filter of Embodiment 2 can be used.

  Since the near-infrared absorption filter of Embodiment 2 is used for the display front plate of this embodiment, the deterioration with time of near-infrared absorption characteristics under high temperature and high humidity use conditions is suppressed.

  Hereinafter, based on an Example, this invention is demonstrated more concretely. The present invention is not limited to the following examples.

(Synthesis Example 1)
94.5 parts by weight of 1-chloro-4-nitrobenzene, 34.5 parts by weight of anhydrous potassium carbonate, and 2 parts by weight of copper powder are prepared for 10.8 parts by weight of p-phenylenediamine, and these are 150 parts by weight of dimethylformamide. The mixture was refluxed with stirring. Refluxing was performed for 15 hours. After this reaction, the reaction mixture was filtered, and the filtrate was thoroughly washed with N, N-dimethylformamide (DMF), water and acetone, then dried and reddish brown N, N, N ′, N′-tetrakis ( 30 parts by weight of (p-nitrophenyl) -p-phenylenediamine was obtained.

Next, 25 parts by weight of N, N, N ′, N′-tetrakis (p-nitrophenyl) -p-phenylenediamine was added to 100 parts by weight of DMF together with 1 part by weight of a palladium-carbon hydrogenation catalyst in the autoclave. At that time, the mixture was stirred at 90 ° C. to 100 ° C. until hydrogen absorption stopped while applying a hydrogen gas pressure of 5.0 kg / cm ² . The reaction solution thus obtained was filtered, and then the filtrate was placed in 350 parts by weight of ice water and stirred for a while, and then the precipitate was filtered. Thereafter, the precipitate was recrystallized in an ethanol-DMF mixed solvent (volume ratio 5: 7) to obtain 14 parts of N, N, N ′, N′-tetrakis (p-aminophenyl) -p-phenylenediamine. It was. The purity of N, N, N ′, N′-tetrakis (p-aminophenyl) -p-phenylenediamine was 95.8% by liquid chromatography analysis.

N, N, N ′, N′-tetrakis (p-aminophenyl) -p-phenylenediamine was analyzed by nuclear magnetic resonance spectrum (d ₆ -DMSO). The absorption of the 20H aromatic ring of a doublet that was broad at δ 6.40 to 6.51 ppm was observed.

  N, N, N ′, N′-tetrakis (p-aminophenyl) -p-phenylenediamine 3.8 parts by weight, DMF 30 parts by weight, potassium carbonate 15 parts by weight, 1-bromo-3-methylbutane 14.5 parts by weight Were prepared, and these were stirred at 100 to 130 ° C. for 8 hours. Next, the obtained reaction solution was placed in 100 parts by weight of ice water and stirred, and then the precipitate was collected by filtration. The precipitate collected by filtration was dried and then purified using a silica gel column, and 3.4 parts by weight of N, N, N ′, N′-tetrakis [p-di (isoamyl) aminophenyl] -p-phenylenediamine was added. Obtained.

  1 part by weight of N, N, N ′, N′-tetrakis [p-di (isoamyl) aminophenyl] -p-phenylenediamine is added to 10 parts by weight of DMF, and is dissolved in 10 parts by weight of DMF with stirring at 70 ° C. (Trifluoromethanesulfone) silver imidoate was added. The number of moles of silver bis (trifluoromethanesulfone) imidate was twice that of N, N, N ′, N′-tetrakis [p-di (isoamyl) aminophenyl] -p-phenylenediamine. After reacting these for 1 hour, the precipitated silver was filtered off. 10 parts by weight of water was added to the filtrate, and the precipitated crystals were collected by filtration and dried. 1.08 parts by weight of compound 1 was obtained. The absorption maximum wavelength of the No. 1 compound was 1081 nm, and the No. 1 compound was a compound exhibiting large absorption with respect to light in the near infrared region.

  7.25 parts by weight of Compound No. 1 obtained as described above was added to 100 parts by weight of polymethyl methacrylate (PMMA), and 738 parts by weight of methyl ethyl ketone was further added as a solvent to form a near infrared absorption layer. The paint for was obtained. This paint was applied to a substrate using a micro gravure coater, and the applied paint was dried to obtain a near infrared absorption filter. The coating was applied so that the film thickness after drying was 4 μm. A 100 μm-thick polyethylene terephthalate (PET) film (“U-34” manufactured by Toray Industries, Inc.) with easy adhesion treatment applied to both the front and back surfaces was used as the base material.

(Comparative example)
N, N, N ′, N′-tetrakis [di- [p-di (n] was used in the same manner as in Synthesis Example 1 except that n-butyl bromide was used instead of 1-bromo-3-methylbutane. -Butyl) aminophenyl] aminophenyl] -p-phenylenediamine was obtained. This compound was reacted with silver hexafluoroantimonate to obtain a diimonium salt compound having a linear alkyl group. Moreover, the near-infrared absorption filter was obtained like this Example using this compound.

(Moisture and heat resistance test)
About the near-infrared absorption filter of an Example and a comparative example, the test preserve | saved at the temperature of 80 degreeC95% RH for 48 hours is performed, and the spectral transmittance before and behind this test is measured with the spectrophotometer (JASCO Corporation make "U-Best V -570 "). And the transmittance | permeability change of the specific wavelength (500 nm, 550 nm, 600 nm, 650 nm, 820 nm, 850 nm, 950 nm, 1000 nm) was calculated. Each result was evaluated according to the following criteria, which are shown in Table 2.

〔Evaluation criteria〕
A: Change in transmittance before and after test is less than 0.5% B: Change in transmittance before and after test is 0.5% or more and less than 1.5% Δ: Change in transmittance before and after test is 1.5% or more and 3.0 Less than% ×: The change in transmittance before and after the test is 3.0% or more

As shown in Table 2, it has an isoamyl group, X is ^{_{(R f SO 2) -N -}} - (SO 2 R f ') (R f and R _f' is a fluoroalkyl group having 1 to 4 carbon atoms) The near-infrared absorption filter of the example (No. 1) using the diimonium salt compound which is an anion represented by is more than the near-infrared absorption filter of the comparative example using the diimonium salt compound having a linear alkyl group, In particular, it was confirmed that the degree of change in transmittance of light having a wavelength of 650 nm to 500 nm was small.

  The near-infrared absorption filter using the diimonium salt compound of the present invention is superior in moisture resistance compared to the conventional near-infrared absorption filter using a diimonium salt compound having a linear alkyl group, so that it can be used in various applications. Can be used. For example, near infrared absorption filters for PDP, automotive glass, building materials and the like can be raised, and are particularly suitable for near infrared absorption filters for PDP. Furthermore, the diimonium compound of the present invention can also be used as an optical recording medium such as CD-R, DVD-R, or a quencher.

Sectional drawing which shows an example of the near-infrared absorption filter of this embodiment Sectional drawing which shows the other example of the near-infrared absorption filter of this embodiment Sectional drawing which shows an example of the front plate for displays of this embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 2 Near-infrared absorption layer 3 Hard coat layer 4 Antireflection layer 4a Medium refractive index film 4b High refractive index film 4c Low refractive index film 11 Display front plate 12 Substrate 13 Near-infrared absorption filter 14 Electromagnetic wave shielding layer 15 Electrode

Claims (12)

A diimonium salt compound having a structure represented by the following formula (1):

However, in formula (1), at least one of R _{1 to} R ₈ is an isoamyl group, and X is (R _f SO ₂ ) —N ⁻ — (SO ₂ R _f ′) (R _f and R _f ′ is an anion represented by a C1-C4 fluoroalkyl group. At least one of ring A and ring B may have a substituent.   The diimonium salt compound according to claim 1, wherein all of the ring A and ring B other than the 1,4-position are unsubstituted. The diimonium salt compound according to claim 1, wherein R _f and R _f ′ are the same perfluoroalkyl group.   The ring according to claim 1, which has at least one substituent selected from the group consisting of a lower alkyl group, a lower alkoxy group, a cyano group, a halogen atom and a hydroxyl group except for the 1,4-positions of ring A and ring B. Diimonium salt compound.   The near-infrared absorption composition containing at least 1 sort (s) of the diimonium salt compound as described in any one of Claims 1-4, and resin.   The near infrared ray absorbing composition according to claim 5, further comprising at least one dye selected from the group consisting of a cyanine dye, a phthalocyanine dye, an azo dye, a squarylium dye, and a dithiol dye.   The near-infrared absorption filter containing at least 1 sort (s) of the diimonium salt compound as described in any one of Claims 1-4.   The near-infrared absorption filter according to claim 7, further comprising at least one dye selected from the group consisting of a cyanine dye, a phthalocyanine dye, an azo dye, a squarylium dye, and a dithiol dye. Comprising a base material, and a near-infrared absorbing layer disposed on one main surface side of the base material,
The near-infrared absorption filter according to claim 7, wherein the near-infrared absorption layer contains at least one diimonium salt compound according to any one of claims 1 to 4.   The near-infrared absorption filter according to claim 9, further comprising an antireflection layer disposed on the opposite side of the main surface of the base on the near-infrared absorption layer side.   The near-infrared absorption filter according to claim 10, further comprising a hard coat layer disposed between the base material and the antireflection layer.   The front plate for a display containing the near-infrared absorption filter of any one of Claims 7-11.

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