JP2005325292A - Near infrared ray-absorbing coloring matter and near infrared ray-blocking filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive near infrared ray-absorbing coloring matter which is excellent in both heat and moisture resistances, has excellent long term stability without deteriorating the near infrared ray absorptivity because of characteristics hardly decomposable with time, is easy to uniformly disperse and dissolve into a resin because of high solubility into the resin, and does not need to add a different type of coloring matter as a second component owing to a capacity of sufficiently absorbing near infrared ray in the vicinity of 850 nm. <P>SOLUTION: This near infrared ray-absorbing coloring mater contains a diimonium salt represented by formula (1) (wherein at least one of R<SP>1</SP>to R<SP>8</SP>is halogenated alkyl in which ≥1 of hydrogen is replaced with halogen, and the others are the same or different and are each alkyl, alkylene, cyanoalkyl, hydroxy, sulfonic acid, alkylsulfonic acid, nitro, amino, alkoxy, aryl, halogen or phenylalkyl; and A<SP>-</SP>is the same or different anion). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a near-infrared absorbing dye that absorbs light in the near-infrared light region, and more particularly to a near-infrared absorbing dye excellent in heat resistance and moisture resistance and a near-infrared blocking filter using the same.

  In recent years, plasma display panels (hereinafter, abbreviated as “PDP”) are generally becoming widespread as demands for larger and thinner displays increase.

  From this PDP, near-infrared light is emitted during use, and an electronic device using a near-infrared remote control may malfunction, and it is necessary to block the near-infrared light with a filter using a near-infrared absorbing dye. Has been.

  Near-infrared blocking filters are also widely used for applications such as optical lenses, automotive glass, and building glass.

  Near-infrared shielding filters used for these applications are required to absorb light in the near-infrared light region while transmitting light in the visible light region, and to have high heat resistance and moisture resistance.

  Conventionally, a diimonium salt compound is known as a pigment that effectively absorbs light in the near infrared region, and various near infrared blocking filters containing this have been proposed (see, for example, Patent Document 1).

  Among the diimonium salt-based near-infrared absorbing dyes exemplified in Patent Document 1, as a relatively excellent heat resistance and moisture resistance, for example, the substituent to nitrogen at the end of the diimonium salt cation is an n-butyl group. Certain N, N, N ′, N′-tetrakis {p-di (n-butyl) aminophenyl} -p-phenylenediimonium salts are known and commonly used.

  However, heat resistance and moisture resistance are still insufficient even when the above-mentioned dye is used, and the near-infrared shielding filter containing the dye is said to decompose with the passage of time and to reduce the near-infrared absorption ability. There was a problem. In addition, since the aminium salt produced by the decomposition causes absorption in the visible light region, the visible light transmittance is lowered, and the near-infrared shielding filter itself is colored yellow, thereby impairing the color tone. .

  In addition, the above dye having a substituent to the terminal nitrogen of the imonium salt cation being an alkyl group has a problem that it is difficult to uniformly disperse and dissolve in the resin because of its low solubility in the resin.

In addition to these problems, when a conventional diimonium salt is used alone as a near-infrared absorbing dye, the near-infrared absorbing ability near 850 nm may be insufficient. For example, a near-infrared blocking filter for PDP In order to compensate for this absorption, it was necessary to add another near-infrared absorbing dye such as a phthalocyanine compound as the second component.
Japanese Patent Laid-Open No. 10-180922

  The present invention has been made in view of such a technical background, and the problem is that it is excellent in heat resistance, moisture resistance and stability, is easily dispersed and dissolved in a resin, and it is necessary to add another kind of near infrared absorbing dye. The object of the present invention is to provide a near-infrared-shielding filter using the near-infrared-absorbing dye that does not have the above-mentioned.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by using a diimonium salt in which a specific substituent is bonded to the nitrogen at the terminal on the cation side. It came.

（式中、Ｒ^１〜Ｒ^８のうち少なくとも一つは、１以上の水素原子がハロゲン原原子で置換されたハロゲン化アルキル基を示し、他は、同一又は異なっていてもよいアルキル基、アルキレン基、シアノアルキル基、水酸基、スルホン酸基、アルキルスルホン酸基、ニトロ基、アミノ基、アルコキシ基、アリール基、ハロゲン原子及びフェニルアルキル基からなる群から選ばれる基を示し、Ａ⁻は、同一又は異なっていてもよいアニオンを示す）
で表されるジイモニウム塩を含む近赤外線吸収色素を提供するものである。 That is, the present invention provides the formula (1)

(In the formula, at least one of R ^{1 to} R ⁸ represents a halogenated alkyl group in which one or more hydrogen atoms are substituted with a halogen primary atom, and the others are the same or different alkyl groups and alkylenes. A group selected from the group consisting of a group, a cyanoalkyl group, a hydroxyl group, a sulfonic acid group, an alkylsulfonic acid group, a nitro group, an amino group, an alkoxy group, an aryl group, a halogen atom and a phenylalkyl group, and A ⁻ is the same Or anion which may be different)
The near-infrared absorption pigment | dye containing the diimonium salt represented by these is provided.

  The present invention also provides a near-infrared shielding filter containing the near-infrared absorbing dye.

  According to the present invention, a near-infrared absorbing dye having excellent heat resistance and moisture resistance and being hardly decomposed over time can be obtained without decreasing the near-infrared absorbing ability and having excellent long-term stability. And since this is highly soluble in the resin and easily dispersed and dissolved in the resin, and has sufficient near-infrared absorbing ability near 850 nm, it is necessary to add another kind of near-infrared absorbing dye as the second component. There is no better one.

The active ingredient of the near-infrared absorbing dye of the present invention is a diimonium salt represented by the above formula (1), and in formula (1), at least one of R ^{1 to} R ⁸ is one or more hydrogen atoms are halogenated It is essential that the halogenated alkyl group be substituted with an atom. Such halogenated alkyl groups in formula (1) may be the same or different. In R ^{1 to} R ⁸ of the diimonium salt represented by the above formula (1), when two or more are halogenated alkyl groups, the number of carbon atoms may be the same or different, but preferably Are the same. In addition, the diimonium salt represented by Formula (1) shall also contain the other resonance structure considered normally.

As a preferable thing of the said halogenated alkyl group, following formula (2)
_{-C n X m H 2n + 1} -m ······ (2)
(Wherein X represents a halogen atom, n represents a natural number of 1 to 12, and m represents a natural number of 1 to 25)
The thing represented by is mentioned.
In the above halogenated alkyl group, the carbon number is in the range of 1 to 12, preferably 1 to 6. When the number of carbon atoms of the halogenated alkyl group exceeds 12, the mass absorption coefficient of the diimonium salt may be lowered.

  The halogen atom of the halogenated alkyl group is not particularly limited and may be any of fluorine, chlorine, bromine and iodine, but a fluorine atom is particularly preferred from the viewpoint of excellent effect of increasing the stability of the diimonium salt. The halogen atom may be one type or two or more types.

  Preferable specific examples of such a halogenated alkyl group include a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a 3,3,3-trifluoropropyl group, and a 4,4,4-trifluorobutyl group. 5,5,5-trifluoropentyl group, 6,6,6-trifluorohexyl group, 8,8,8-trifluorooctyl group, 2-methyl-3,3,3-trifluoropropyl group, perfluoro Fluorinated alkyl groups such as ethyl group, perfluoropropyl group, perfluorobutyl group, perfluorohexyl group, perfluorooctyl group, 2-trifluoro-perfluoropropyl group; trichloromethyl group, 2,2,2-trichloroethyl group, 3, 3,3-trichloropropyl group, 4,4,4-trichlorobutyl group, 5,5,5-trichloropentyl group, , 6,6-trichlorohexyl group, 8,8,8-trichlorooctyl group, 2-methyl-3,3,3-trichloropropyl group, perchloroethyl group, perchloropropyl group, perchlorobutyl group, perchloro Alkyl chloride groups such as hexyl group, perchlorooctyl group, 2-trichloro-perchloropropyl group; tribromomethyl group, 2,2,2-tribromoethyl group, 3,3,3-tribromopropyl group, 4 , 4,4-tribromobutyl group, 5,5,5-tribromopentyl group, 6,6,6-tribromohexyl group, 8,8,8-tribromooctyl group, 2-methyl-3,3 , 3-tribromopropyl group, perbromoethyl group, perbromopropyl group, perbromobutyl group, perbromohexyl group, perbromooctyl group, 2-tribromo-pe Alkyl bromide group such as bromo propyl group.

  Among these, particularly preferred specific examples are trifluoromethyl group, 2,2,2-trifluoroethyl group, 3,3,3, -trifluoropropyl group, 4,4,4-trifluorobutyl group, perfluoro Examples include an ethyl group, a perfluoropropyl group, and a perfluorobutyl group.

In the present invention, it is essential that at least one of R ^{1 to} R ⁸ in the formula (1) is a halogenated alkyl group, and preferably a halogenated alkyl group of the formula (2). It is more preferable that four or more of them are halogenated alkyl groups represented by the above formula (2). Furthermore, it is particularly preferable that all the substituents are halogenated alkyl groups represented by the above formula (2) because they have good heat resistance, moisture resistance and solubility, and a large absorption around 850 nm. More preferably, all the substituents are the same halogenated alkyl group represented by the above formula (2).

On the other hand, in R ^{1 to} R ⁸ in the formula (1), substituents other than the halogenated alkyl group are an alkyl group, an alkylene group, a cyanoalkyl group, a hydroxyl group, a sulfonic acid group, an alkylsulfonic acid group, a nitro group, an amino group. A group, an alkoxy group, an aryl group, a halogen atom or a phenylalkyl group.

  Although there is no limitation in particular as said alkyl group, A C1-C12 alkyl group is preferable, 1-8 pieces are especially preferable, and 2-6 pieces are still more preferable. Such an alkyl group may be linear or branched. Specific examples include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a dodecyl group. Particularly preferred specific examples include an ethyl group, an n-propyl group, an isopropyl group, an n -A butyl group, an isobutyl group, n-pentyl group, an isoamyl group, etc. are mentioned.

  The alkylene group is not particularly limited, but an alkylene group having 1 to 12 carbon atoms is preferable. Such an alkylene group may be linear or branched, and the number and position of double bonds are not particularly limited. A particularly preferred specific example is an allyl group.

  The cyanoalkyl group is not particularly limited, but is preferably a cyanoalkyl group having 1 to 12 carbon atoms, and the number of substituted cyano groups is preferably 1 to 3. Particularly preferred specific examples include propyl nitrile group, butyronitrile group, pentyl nitrile group, 1-methyl-butyronitrile group, 1-methyl-butyronitrile group and the like.

  The alkylsulfonic acid group is not particularly limited, but an alkylsulfonic acid group having 1 to 6 carbon atoms is preferable. Particularly preferred specific examples include a methylsulfonic acid group, an ethylsulfonic acid group, a propylsulfonic acid group, and a butylsulfonic acid group.

  The alkoxy group is not particularly limited, but an alkoxy group having 1 to 12 carbon atoms is preferable. Particularly preferred specific examples include methoxy group, ethoxy group, propoxy group, butoxy group and the like.

  The aryl group is not particularly limited, and examples thereof include an optionally substituted phenyl group, naphthyl group, tolyl group, furyl group, and pyridyl group. Particularly preferred specific examples include a phenyl group and a tolyl group.

  In the formula (1), the halogen atom as a substituent other than the halogenated alkyl group is not particularly limited, but a chlorine atom, a fluorine atom and the like are preferable.

  The phenylalkyl group in formula (1) preferably has 1 to 18 carbon atoms, particularly preferably 1 to 8 carbon atoms in the alkyl group. Furthermore, the phenyl group may not have a substituent, but from the group consisting of an alkyl group, a hydroxyl group, a sulfonic acid group, an alkyl sulfonic acid group, a nitro group, an amino group, an alkoxy group, a halogenated alkyl group, and a halogen. It may have at least one selected substituent.

  Specific examples of the phenylalkyl group include benzyl group, phenethyl group, phenylpropyl group, phenyl-α-methylpropyl group, phenyl-β-methylpropyl group, phenylbutyl group, phenylpentyl group, and phenyloctyl group. It is done. Most preferred are benzyl group, phenethyl group and the like.

On the other hand, in the formula (1) of the present invention, A ^- is not particularly limited for anion represented by, sulfonimide anion represented by the following formula (3) is, heat resistance and further improve the moisture resistance particularly preferable.

（式中、Ｒ’及びＲ”は、それぞれ同一又は異なっていてもよいフルオロアルキル基を示すか、又はそれらが一緒になって形成するフルオロアルキレン基を示す）

(In the formula, R ′ and R ″ each represent a fluoroalkyl group which may be the same or different, or represent a fluoroalkylene group formed by them together)

  In the formula (3), R ′ and R ″ are the same or different fluoroalkyl groups or fluoroalkylene groups formed by combining them, and the number of substituted fluorine atoms and The number of carbons is not particularly limited, but preferred examples of R ′ and R ″ include perfluoroalkyl groups having 1 to 8 carbons which may be the same or different. That is, a preferable example is an anion represented by the formula (4).

（式中、ｎ及びｎ’は、１〜８の整数を示す）

(Wherein n and n ′ represent an integer of 1 to 8)

  Here, n and n ′ are more preferably integers of 1 to 4. Preferable specific examples include, for example, bis (trifluoromethanesulfone) imide, bis (pentafluoroethanesulfone) imide, and the like that have the same perfluoroalkanesulfonyl group (n = n ′), and different perfluoroalkanesulfonyl groups. (N ≠ n ′) pentafluoroethanesulfone trifluoromethanesulfonimide, trifluoromethanesulfone heptafluoropropanesulfonimide, nonafluorobutanesulfone trifluoromethanesulfonimide, and the like. Among these, the perfluoroalkanesulfonyl group is the same (n Bis (trifluoromethanesulfone) imide or bis (pentafluoroethanesulfone) imide in which n = n ′) and n and n ′ are 1 or 2 are more preferable in terms of near infrared absorption ability.

  Moreover, as another preferable organic group of R ′ and R ″ in the anion in the formula (3), a C2-C12 fluoroalkylene group formed by combining them may be mentioned. The number of fluorines and the number of hydrogens are not particularly limited, but particularly preferred are perfluoroalkylene groups having 2 to 12 carbon atoms which are formed together, that is, heat resistance and moisture resistance. In terms of this, a particularly preferred anion is an anion represented by the formula (5).

（式中、ｍは、２〜１２の整数を示す）

(In the formula, m represents an integer of 2 to 12)

  Here, m is preferably 2 to 8, and more preferably m is 3. Specifically, 1,3-disulfonylhexafluoropropyleneimide represented by the following formula (6) is exemplified.

Furthermore, the anion A ⁻ used in the near-infrared absorbing dye represented by the formula (1) of the present invention is selected from the group consisting of a hexafluoroantimonate anion, a hexafluorophosphate anion, a tetrafluoroborate anion, and a perchlorate anion. One kind or two or more kinds of anions selected are also preferable because they are excellent in heat resistance and moisture resistance.

Moreover, as A < ^- > in Formula (1), 1 type, or 2 or more types of organics chosen from the group which consists of a trifluoromethanesulfonic acid anion, a tetrafluoroethanesulfonic acid anion, a perfluorobutanesulfonic acid anion, and a trifluoroacetic acid anion. An anion is also preferable in that it has excellent heat resistance and moisture resistance.

In the formula (1), the anion A ⁻ may be used alone or a double salt composed of two kinds. Moreover, the mixture which consists of 2 or more types may be sufficient.

  Next, an example of a method for producing dimonium salt (1), which is an active ingredient of the near-infrared absorbing dye of the present invention, is as follows.

  That is, an amino compound represented by the following formula (7) obtained by the Ullmann reaction and the reduction reaction is converted to N-methyl-2-pyrrolidone (hereinafter abbreviated as “NMP”), dimethylformamide (hereinafter referred to as “DMF”). And a corresponding halogenated alkane such as 1-iodofluoroalkane and a carbonate of an alkyl metal as a deiodinating agent, and 30 to 150 ° C, preferably 70 to 120. The reaction is carried out at 0 ° C. to obtain an alkyl halide-substituted product represented by the following formula (8). At this time, a part of the corresponding halogenated alkane iodide may be replaced with a corresponding iodoalkane; alkoxy iodo; benzene iodide; phenyl-1-iodoalkane such as benzyl iodide or phenethyl iodide.

（式中、Ｒ^１〜Ｒ^８は、前記した意味を有する）

(Wherein R ^{1 to} R ⁸ have the above-mentioned meanings)

Subsequently, the halogenated alkyl-substituted product represented by the above formula (8) and the corresponding silver salt of an anion A ⁻ are heated in an organic solvent such as NMP, DMF, and acetonitrile at a temperature of 30 to 150 ° C., preferably 40 to 80 ° C. After reacting and separating the precipitated silver, a precipitate such as water, ethyl acetate, hexane or the like is added and the resulting precipitate is filtered to obtain a diimonium salt represented by the above formula (1).

In the diimonium salt (1), when R ^{1 to} R ⁸ are two or more different substituents, an iodinated halogenated alkane compound having the number of moles corresponding to the number of substituents is added, and after the reaction, Sequentially corresponding different numbers of moles of iodinated halogenated alkanes; corresponding iodoalkanes; alkoxyiodos; benzene iodides; phenyl-1-iodoalkanes such as benzyl iodide and phenethyl iodide, etc. It is also possible to obtain the same by adding the different types of iodides simultaneously.

  The diimonium salt (1) thus obtained is further used as an active ingredient of the near-infrared absorbing dye of the present invention, in addition to acrylic resins, polyester resins, polycarbonate resins, urethane resins, cellulose resins, polyisocyanate resins, polyisocyanates. A near-infrared shielding filter can be obtained by mixing with a resin such as an arylate resin or an epoxy resin.

  At this time, it is possible to use only one or two or more near-infrared absorbing dyes of the present invention. However, when the near-infrared blocking performance near the wavelength of 850 nm is slightly insufficient, phthalocyanine dyes, dithiols are further used. Known pigments such as a metal complex may be added. Further, in order to improve the light resistance, a UV-absorbing dye such as benzophenone or benzotriazole may be further added. If necessary, the color tone may be adjusted by adding a known dye having absorption in the visible light region.

  Although the near-infrared transmittance of the near-infrared blocking filter of the present invention can be controlled by changing the mixing ratio of the near-infrared absorbing dye of the present invention to the resin, the near-infrared absorbing dye of the present invention is based on 100 parts by weight of the resin. Is preferably mixed in the range of 0.01 to 30 parts by weight. When the amount is less than 0.01 part by weight, the near infrared ray blocking ability may be insufficient, and when the amount is more than 30 parts by weight, the visible light transmittance may also decrease.

  Although the manufacturing method of the near-infrared shielding filter of this invention is not specifically limited, Well-known manufacturing methods, such as a casting method and a melt extrusion method, are mentioned.

  Among these, the cast method is a method in which the near-infrared absorbing dye of the present invention is dissolved or dispersed in a solution in which a resin and a solvent are mixed, and then on a transparent film such as polyester or polycarbonate, a panel, a support such as a glass substrate. In addition, the solution is applied and dried to form a film.

  Although there is no limitation in particular as a solvent used for the said casting method, Organic solvents, such as methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, tetrahydrofuran, 1, 4- dioxane, or the solvent which mixed these can be used.

  The melt extrusion method is a method in which the near-infrared absorbing dye of the present invention and a resin are melted and kneaded and then molded into a panel shape by extrusion molding.

  Conventionally, near-infrared absorbing dyes containing a diimonium salt that does not have a halogenated alkyl group as a terminal group may lack near-infrared absorbing ability near 850 nm when used alone. In the filter, it was necessary to add a second pigment such as a phthalocyanine compound in order to compensate for this lack of absorption capacity. On the other hand, the near-infrared absorbing dye containing the diimonium salt (1) having a halogenated alkyl group as a terminal group of the present invention has an absorption wavelength shifted to the short wavelength side, so the amount of the second dye added Even if it is reduced or no additive is added, a near infrared ray absorbing ability that satisfies the required performance can be obtained.

  Further, although the reason why the diimonium salt (1) having an alkyl halide group as a terminal group according to the present invention exhibits high heat resistance and moisture resistance is not clear, it has absorption in the visible light region (around 480 nm) and becomes yellow. This is probably because the aminium salt compound that causes coloration is difficult to be generated by decomposition.

  EXAMPLES Next, although an Example is given and this invention is further demonstrated, this invention is not limited to these Examples. In the examples, “part” means “part by weight”.

Example 1
(1) 100 parts of DMF, 10 parts of N, N, N ′, N′-tetrakis (p-aminophenyl) -p-phenylenediamine, 63 parts of 1-iodo-4,4,4-trifluorobutane and 30 parts of potassium carbonate Part was added and reacted at 120 ° C. for 10 hours.

  Next, the reaction solution is added to 500 parts of water, and the resulting precipitate is filtered, washed with 500 parts of methyl alcohol, dried at 100 ° C., and N, N, N ′, N′-tetrakis {p-di ( There was obtained 24.1 parts of 4,4,4-trifluorobutyl) aminophenyl} -p-phenylenediamine.

  (2) To 24.1 parts of the obtained N, N, N ′, N′-tetrakis {p-di (4,4,4-trifluorobutyl) aminophenyl} -p-phenylenediamine, 200 parts of DMF and hexa 12.9 parts of silver fluoroantimonate was added and reacted at 60 ° C. for 3 hours, and the resulting silver was filtered off.

  Subsequently, 200 parts of water was added to the filtrate, and the formed precipitate was filtered and dried to give hexafluoroantimonic acid-N, N, N ′, N′-tetrakis {p-di (4,4,4 -Trifluorobutyl) aminophenyl} -p-phenylene dimonium near-infrared absorbing dye 28.0 parts was obtained.

  (3) In the solution obtained by adding 34 parts of methyl ethyl ketone and 34 parts of toluene to 30 parts of acrylic lacquer resin (manufactured by Soken Chemical Co., Ltd., registered trademark Thermolac LP-45M), the near infrared absorbing dye 2 Part was dissolved. This solution was applied onto a commercially available general-purpose polymethacrylic resin film (thickness: 125 μm) using a bar coater having a gap size of 46 μm. Subsequently, it was dried at a temperature of 100 ° C. for 3 minutes to obtain a near-infrared shielding filter.

Examples 2-4
Table 1 was prepared in the same manner as in Example 1 except that instead of 63 parts of 1-iodo-4,4,4-trifluorobutane used in Example 1, the same number of moles of the compounds shown in Table 1 were used. The described near infrared absorbing dye was obtained. Subsequently, using the obtained near-infrared absorbing dye, a near-infrared shielding filter was obtained in the same manner as in Example 1.

Example 5
To 24.1 parts of N, N, N ′, N′-tetrakis {p-di (4,4,4-trifluorobutyl) aminophenyl} -p-phenylenediamine obtained in the same manner as in Example 1, acetone was added. 250 parts and 14.5 parts of silver bis (trifluoromethanesulfonyl) imidate were added and reacted at 60 ° C. for 3 hours, and the produced silver was separated by filtration.

  Next, 200 parts of water was added to the filtrate, and the resulting precipitate was filtered and dried, and bis (trifluoromethanesulfonyl) imidic acid-N, N, N ′, N′-tetrakis {p-di (4 , 4,4-trifluorobutyl) aminophenyl} -p-phenylenediimonium, 29.9 parts of a near infrared absorbing dye. Next, a near infrared ray blocking filter was obtained in the same manner as in Example 1 using the obtained near infrared absorbing dye.

Examples 6-8
Table 1 was prepared in the same manner as in Example 5 except that instead of 63 parts of 1-iodo-4,4,4-trifluorobutane used in Example 5, the same number of moles of the compounds shown in Table 1 were used. The described near infrared absorbing dye was obtained. Subsequently, using the obtained near-infrared absorbing dye, a near-infrared shielding filter was obtained in the same manner as in Example 1.

Examples 9-12
Instead of 63 parts of 1-iodo-4,4,4-trifluorobutane used in Example 5, the same mole number of the compounds shown in Table 1 was used, and silver bis (trifluoromethanesulfonyl) imidate 14.5 In the same manner as in Example 5 except that silver 1,3-disulfonylhexafluoropropylimidate having the same number of moles was used instead of the parts, near-infrared absorbing dyes described in Table 1 were obtained. Subsequently, using the obtained near-infrared absorbing dye, a near-infrared shielding filter was obtained in the same manner as in Example 1.

Comparative Example 1
In the same manner as in Example 1, except that 1-iodobutane having the same number of moles was used instead of 63 parts of 1-iodo-4,4,4-trifluorobutane used in Example 1, the vicinity shown in Table 1 was used. An infrared absorbing dye was obtained. Further, a near-infrared shielding filter was obtained in the same manner as in Example 1.

Evaluation example <maximum absorption wavelength and molar extinction coefficient>
Table 2 shows the maximum absorption wavelength (hereinafter abbreviated as “λmax”) and the molar absorption coefficient at λmax (hereinafter abbreviated as “ε”) of the near-infrared absorbing dyes synthesized in Examples 1 to 5 and Comparative Example 1. Shown in Moreover, the wavelength dependence of the transmittance | permeability of the near-infrared cutoff filter of Example 1 and Comparative Example 1 is shown in FIGS. 1 and 2, respectively.

  Comparing FIG. 1 and FIG. 2, in the near-infrared absorbing dye of the present invention of Example 1, λmax is shifted to the short wavelength side and the absorption at 750 nm to 900 nm is increased as compared with the dye of Comparative Example 1. Was. Further, as can be seen from Table 1, in the near-infrared absorbing dyes of the present invention of Examples 1 to 5, λmax was shifted to the short wavelength side as compared with the dye of Comparative Example 1. From this, it was found that the near-infrared absorbing dye of the present invention does not need to add another dye such as a phthalocyanine dye. Moreover, it was found that the near-infrared absorbing dyes of Examples 1 to 5 have a large ε and can sufficiently block near-infrared rays.

<80 ° C heat resistance test>
The near-infrared blocking filters of Examples 1 to 4 and Comparative Example 1 were stored in an atmosphere at a temperature of 80 ° C. and subjected to a heat resistance test. The initial absorbance at a wavelength of 1000 nm was taken as 100%, and the absorbance after a predetermined time had elapsed. Percentage was calculated as dye residual rate. The light transmittance at a wavelength of 480 nm was measured. These results are shown in Table 3.

<105 ° C heat resistance test>
The near-infrared blocking filters of Examples 5 to 12 and Comparative Example 1 were stored in an atmosphere at a temperature of 105 ° C. and subjected to a heat resistance test. The initial absorbance at a wavelength of 1000 nm was taken as 100%, and the absorbance after a predetermined time had elapsed. Percentage was calculated as dye residual rate. The light transmittance at a wavelength of 480 nm was measured. These results are shown in Table 4.

<Moisture resistance test>
The near-infrared cutoff filters of Examples 1 to 4 and Comparative Example 1 were stored in an atmosphere at a temperature of 60 ° C. and a humidity of 95%, and the dye residual rate and light transmittance were measured in the same manner as in the heat resistance test. These results are shown in Table 5.

  As shown in Tables 3 to 5, the near-infrared blocking filter using the conventional near-infrared absorbing dye (Comparative Example 1) decomposes with the passage of time, and the absorbance in the near-infrared region near the wavelength of 1000 nm decreases. have done. Furthermore, the visible light transmittance decreased with time, and the color tone was impaired due to the yellow coloration. Compared to this, the near-infrared blocking filter containing the near-infrared absorbing dyes of Examples 1 to 12 has little decrease in absorbance in the near-infrared region, and coloration in the visible light region due to the decomposition of the dye is difficult to occur. It was. From this, it was found that the near-infrared absorbing dyes of Examples 1 to 12 had higher heat resistance and moisture resistance than the dye of Comparative Example 1.

  The near-infrared absorbing dye comprising the dimonium salt (1) of the present invention as an active ingredient is excellent in heat resistance and moisture resistance and does not deteriorate near-infrared absorbing ability over a long period of time, and contains the near-infrared absorbing dye of the present invention. The made near-infrared shielding filter can be used for various applications.

  The near-infrared shielding filter is used, for example, for PDP, automotive glass, building glass, and the like, and is particularly suitable for a near-infrared shielding filter for PDP.

It is a figure which shows the light transmittance of the near-infrared shielding filter produced in Example 1. FIG. It is a figure which shows the light transmittance of the near-infrared shielding filter produced in the comparative example 1. that's all

Claims (12)

The following formula (1)

(In the formula, at least one of R ^{1 to} R ⁸ represents a halogenated alkyl group in which one or more hydrogen atoms are substituted with a halogen atom, and the others are the same or different alkyl groups and alkylene groups. , A cyanoalkyl group, a hydroxyl group, a sulfonic acid group, an alkylsulfonic acid group, a nitro group, an amino group, an alkoxy group, an aryl group, a halogen atom, and a phenylalkyl group, and A ⁻ are the same or Indicates anion that may be different)
A near-infrared absorbing dye containing a diimonium salt represented by A halogenated alkyl group in which one or more hydrogen atoms are substituted with a halogen atom is represented by the following formula (2):

_{-C n X m H 2n + 1} -m ······ (2)

(Wherein X represents a halogen atom, n represents a natural number of 1 to 12, and m represents a natural number of 1 to 25)
The near-infrared absorption pigment | dye containing the diimonium salt represented by these. The near-infrared absorbing dye according to claim 1, wherein in formula (1), all of R ^{1 to} R ⁸ are halogenated alkyl groups represented by formula (2).   The near-infrared absorbing dye according to claim 2 or 3, wherein X in the formula (2) is a fluorine atom. In formula (1), A ⁻ represents the following formula (3)

(In the formula, R ′ and R ″ each represent a fluoroalkyl group which may be the same or different, or represent a fluoroalkylene group formed by them together)
The near-infrared absorbing dye according to claim 1, wherein the anion is an anion represented by the formula:   6. The near-infrared absorbing dye according to claim 5, wherein R 'and R "in formula (3) are each a C1-8 perfluoroalkyl group which may be the same or different.   6. The near-infrared absorbing dye according to claim 5, wherein R ′ and R ″ in formula (3) are both a trifluoromethyl group or a pentafluoroethyl group.   6. The near-infrared absorbing dye according to claim 5, wherein the fluoroalkylene group formed by combining R 'and R "in formula (3) is a perfluoroalkylene group having 2 to 12 carbon atoms.   6. The near-infrared absorbing dye according to claim 5, wherein the fluoroalkylene group formed by combining R ′ and R ″ in formula (3) is a hexafluoropropylene group. In formula (1), A ⁻ is one or more anions selected from the group consisting of a hexafluoroantimonate anion, a hexafluorophosphate anion, a tetrafluoroborate anion and a perchlorate anion. The near-infrared absorbing dye according to claim 4. In Formula (1), A ⁻ is one or more anions selected from the group consisting of a trifluoromethanesulfonate anion, a tetrafluoroethanesulfonate anion, a perfluorobutanesulfonate anion, and a trifluoroacetate anion. The near-infrared absorbing dye according to any one of claims 1 to 4. A near-infrared cut-off filter comprising the near-infrared absorbing dye according to any one of claims 1 to 11.

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