JPWO2007099990A1 - Near-infrared absorbing film and optical filter for plasma display panel using the same - Google Patents

Abstract

We will develop a near-infrared absorbing film that contains a diimonium compound having a relatively wide near-infrared absorption wavelength range, has good heat resistance, moist heat resistance, and other physical properties, and further develops an optical filter for PDPs using this film. A near-infrared absorbing film prepared by laminating a mixture of diimonium compounds having different n's of formula (1) on a transparent support film or containing in a pressure-sensitive adhesive layer is prepared, and an optical filter for PDP is prepared using this. (In Formula (1), n-Pr represents a normal propyl group, iso-Bu represents an isobutyl group, and n represents an integer of 0 to 8, respectively.)

Description

  INDUSTRIAL APPLICABILITY The present invention absorbs light having a wavelength in the near-infrared region, and uses a near-infrared absorbing film using a diimmonium compound having excellent heat resistance, moist heat resistance and solvent solubility, and a plasma display panel (hereinafter referred to as PDP) using the same. ) Optical filter.

  Near-infrared rays are used as a beam for remote control of electrical equipment, so equipment that emits near-infrared rays may cause malfunction of electrical equipment installed in the vicinity. It is necessary to install an optical filter or the like having a function of shielding near-infrared rays on the front surface of a class (for example, PDP).

  The principle of PDP is that light is applied to the cell wall by applying a voltage to a rare gas (neon, xenon, etc.) enclosed in a cell sandwiched between two sheet-like glasses, and emitting ultraviolet light emitted from the rare gas in a plasma state. It hits the body to generate the visible light necessary for the image, but at the same time as the visible light, orange light near the wavelength of 595 nm (hereinafter referred to as neon light) reduces the color purity of the red light due to near infrared rays, electromagnetic waves, and neon gas. It also emits electromagnetic waves that are harmful to people, electrical devices, etc., so that useful visible light is transmitted, but harmful electromagnetic waves such as near infrared rays must be shielded. An optical filter or the like is required.

  Near-infrared absorbing films used for optical filters are used for the purpose of shielding near-infrared rays, and compounds having a function of absorbing near-infrared rays (near-infrared absorbing compounds) are used for this purpose. That is, these near-infrared absorptive compounds have transparent functionalities such as transparent support films (transparent substrate films and anti-reflection films, or films that shield electromagnetic waves harmful to the human body (hereinafter referred to as electromagnetic shielding films)). Film) A near-infrared absorbing film is produced by including in a layer provided on the surface. There are several types of near-infrared absorbing compounds used here, but a diimonium compound having a relatively wide absorption wavelength range of near-infrared is used alone or based on this one or more other types of near-infrared rays. Often used in combination with absorbent compounds. However, many compounds having near-infrared absorptivity are insufficient in heat stability and moist heat resistance (hereinafter simply referred to as “thermal stability”), and the same applies to diimonium compounds. I can say that. In addition, diimonium compounds having hexafluoroantimonate ions have generally been used as diimonium compounds, but these compounds are classified as deleterious substances, and restrictions on the use of heavy metals etc. are becoming strict due to environmental problems. For this reason, a safer diimonium compound has been desired. As means for solving this, a compound using an organic counter ion such as naphthalenedisulfonic acid (Patent Document 1) and a compound using trifluoromethanesulfonic acid ion (Patent Document 2) are disclosed. In particular, in the case of a near-infrared absorbing film containing these compounds in the adhesive layer, the layer containing these compounds is discolored or the near-infrared absorptivity is deteriorated. There is.

  The main specific method for retaining the near-infrared absorbing compound on the transparent support film is to dissolve and / or disperse it together with the binder resin in a solvent and apply it onto the transparent resin film to form a polymer resin layer. There are two methods, the method and the method of inclusion in the adhesive layer. In the former case, “thermal stability” is characterized by being easily affected by the glass transition temperature of the binder resin used and the amount of residual solvent in the resin layer. On the other hand, the latter method is characterized in that “thermal stability” tends to be lowered, and there is a concern that the haze value which is one standard of transparency and the transmittance of visible light are adversely affected.

As a technique for stabilizing a diimonium compound in a layer (a layer provided using a polymer resin such as an overcoat layer, an adhesive layer, a treatment layer) provided on a transparent support film, Patent Literature 3 discloses that the amount of the solvent remaining in the layer provided on the transparent support film can be stabilized by containing a diimonium compound in a state of being controlled to a certain ratio or less, or by using a binder resin having a high glass transition temperature. However, it is difficult to say that it is a simple method because it requires time and effort to control the amount of residual solvent and there are restrictions on the binder resin used. In addition, there has been no report on a method for effectively preventing adverse effects on the haze value and visible light transmittance when a diimonium compound is contained in an adhesive layer provided on a transparent support film.
In any case, by using a diimonium compound that is relatively excellent in near-infrared absorptivity, without impairing the near-infrared absorptivity, its "thermal stability", and there is no restriction on the binder resin used, as an optical filter The establishment of a simple manufacturing technique for a near-infrared absorbing film having excellent performance has been demanded.
Literature list
JP 10-316633 A (page 5) Japanese Patent Publication No. 7-51555 (2nd page) JP 2000-227515 A Japanese Patent Publication No. 43-25335 (pages 7-14)

  In a diimonium compound having a relatively wide absorption wavelength region in the near-infrared region, it is easy to handle due to its good solvent solubility, and the glass transition temperature (hereinafter referred to as Tg) of the binder resin that can be used is wide. Finding diimonium compounds that can retain excellent "thermal stability" even when they are contained, can absorb near infrared rays efficiently, can keep haze values lower, and can be synthesized at low cost, and have excellent performance using this It is an object of the present invention to provide an optical filter having

  As a result of intensive studies, the present inventors have solved the above-mentioned problem by a mixture of diimonium compounds having a specific substituent on the cation side and a specific anion selected as the anion. As a result, the present invention was completed.

That is, the present invention is (1) a near-infrared absorption characterized in that a mixture of two or more diimonium compounds represented by the following formula (1) and different n is contained in a layer formed on a transparent support film. the film,

（式（１）中、ｎ−Ｐｒはノルマルプロピル基を、ｉｓｏ−Ｂｕはイソブチル基をそれぞれ表し、ｎは０〜８の整数を表す。）
（２）式（１）のｎが異なる２種以上のジイモニウム化合物の混合物が、式（１）におけるｎが３〜６のジイモニウム化合物を７０％（マススペクトルより算出）以上９８％以下含有するものである（１）に記載の近赤外線吸収フィルム、
（３）透明支持フィルム上に形成された層が粘着層である（１）又は（２）に記載の近赤外線吸収フィルム、
（４）透明支持フィルム上に形成された層に、式（１）のｎが異なる２種以上のジイモニウム化合物の混合物及び波長５５０〜６２０ｎｍに極大吸収を有する化合物が含有される（１）乃至（３）のいずれか一項に記載の近赤外線吸収フィルム、
（５）透明支持フィルムが減反射機能又は電磁波遮蔽機能を有するフィルムである（１）乃至（４）のいずれか一項に記載の近赤外線吸収フィルム、
（６）（１）乃至（５）のいずれか一項に記載の近赤外線吸収フィルムを含むプラズマディスプレイパネル用光学フィルタ、
（７）（１）乃至（５）のいずれか一項に記載の近赤外線吸収フィルムと、電磁波遮蔽能を有するフィルム及び／又は減反射機能を有するフィルムを含む（６）に記載のプラズマディスプレイパネル用光学フィルタ、
（８）式（１）で表され、ｎが異なる２種以上のジイモニウム化合物の混合物

(In Formula (1), n-Pr represents a normal propyl group, iso-Bu represents an isobutyl group, and n represents an integer of 0 to 8.)
(2) A mixture of two or more diimonium compounds having different n in formula (1) contains 70% (calculated from mass spectrum) or more and 98% or less of diimonium compounds having n of 3 to 6 in formula (1) The near infrared ray absorbing film according to (1),
(3) The near-infrared absorbing film according to (1) or (2), wherein the layer formed on the transparent support film is an adhesive layer,
(4) The layer formed on the transparent support film contains a mixture of two or more diimonium compounds having different n in formula (1) and a compound having a maximum absorption at a wavelength of 550 to 620 nm (1) to ( 3) The near-infrared absorbing film according to any one of
(5) The near-infrared absorbing film according to any one of (1) to (4), wherein the transparent support film has a reduced reflection function or an electromagnetic wave shielding function.
(6) An optical filter for a plasma display panel comprising the near-infrared absorbing film according to any one of (1) to (5),
(7) The plasma display panel according to (6), comprising the near-infrared absorbing film according to any one of (1) to (5), a film having an electromagnetic wave shielding ability, and / or a film having a function of reducing reflection. Optical filters,
(8) Mixture of two or more diimonium compounds represented by formula (1) and different n

（式（１）中、ｎ−Ｐｒはノルマルプロピル基を、ｉｓｏ−Ｂｕはイソブチル基をそれぞれ表し、ｎは０〜８の整数を表す）
に関する。

(In formula (1), n-Pr represents a normal propyl group, iso-Bu represents an isobutyl group, and n represents an integer of 0 to 8)
About.

  The mixture of diimonium compounds used in the present invention can be synthesized inexpensively by a simple method, does not contain heavy metals such as antimony, is not a deleterious substance, has good solvent solubility, and is easy to handle. The obtained near-infrared absorbing film absorbs near-infrared light in the wavelength range of 800 to 1100 nm well, and even when this is contained in the adhesive layer, exhibits excellent haze value and “thermal stability”, and absorbs near-infrared light. The optical filter for PDP that combines this near-infrared absorbing film and other functional film exhibits excellent performance and can sufficiently cope with the above problems. is there.

The present invention will be described in detail below.
The near-infrared absorbing film of the present invention is a mixture of two or more types of diimonium compounds having different numbers of normal propyl groups and isobutyl groups, which are substituents of the diimonium compound represented by the formula (1) (hereinafter referred to as “the present diimonium mixture”). Is also a near-infrared absorbing film containing a binder resin layer or adhesive layer provided on a transparent support film, has good physical properties as an optical film, and has good near-infrared in the wavelength range of 800 to 1100 nm. Absorb.

  The near-infrared absorbing film having a layer containing “the present dimonium mixture” has good near-infrared absorptivity and excellent “thermal stability”. When included in the adhesive layer, the near-infrared absorbing film has a substituent of formula (1). It is characterized by excellent near-infrared absorption ability and low haze value than diimonium compounds, all of which are isobutyl groups (n = 0), and all of the substituents of formula (1) are (n = 8) It was found that the solvent solubility was better than that of the diimonium compound and coating was easy. The “diimonium mixture” can be easily produced, and can be easily produced by a conventionally known method by adjusting the ratio of the amount of the alkylating agent added in the precursor production process as described below.

  In the present invention, the “present dimonium mixture” can be obtained, for example, according to the method described in Patent Document 4. That is, an amino compound represented by the following formula (2) obtained by the Ullmann reaction and reduction reaction is preferably used in an organic solvent, such as dimethylformamide (DMF), dimethylimidazolidinone (DMI), N-methylpyrrolidone (NMP), etc. In a water-soluble polar solvent, a normal propyl compound and an isobutyl compound halogenated at 30 to 160 ° C., preferably 50 to 140 ° C., are mixed at an arbitrary ratio, and reacted to obtain a mixture of compounds represented by formula (3) Can be obtained. In order to control the ratio of normal propyl group to isobutyl group, a compound corresponding to normal propyl group (or isobutyl group) is reacted first, and then a compound corresponding to isobutyl group (or normal propyl group). It is also possible to synthesize a mixture of a certain proportion of compounds.

(In formula (3), n represents the same meaning as in formula (1).)
The mixture of formula (3) synthesized above is 0-100 in an organic solvent, preferably in a water-soluble polar solvent such as dimethylformamide (DMF), dimethylimidazolidinone (DMI), N-methylpyrrolidone (NMP). At 2 ° C., preferably 5 to 70 ° C., 2 equivalents of tris (trifluoromethylsulfonyl) carbonic acid is added to carry out an oxidation reaction to obtain “the present diimmonium mixture” used in the present invention.

Next, how to determine the composition ratio of each diimonium compound in the “diimonium mixture” will be described.
Mass spectrometer for measuring molecular ion peak intensity of each dimonium compound (9 kinds of dimonium compounds in which n is 0, 1, 2, 3, 4, 5, 6, 7, or 8 in formula (1)) As an example, LCT manufactured by Micromass was used. The sample for measurement for calculating the composition ratio of each diimonium compound depended on the compound of the formula (3) before the cationization (hereinafter referred to as a precursor), and this is the result of “the present dimonium mixture” after cationization. This is because direct measurement is difficult, the reliability of the measured value is lacking, and the composition ratio of each precursor can be determined to be extremely correlated with the composition ratio of each component after cationization. Specifically, the electrospray (ESI) ionization mass spectrum of the measurement sample was measured, the molecular ion peak intensity [M] ⁺ of each precursor was determined, and the composition ratio was calculated. The composition ratio A of each component was estimated and calculated from A (%) = 100 × [M] ⁺ / (total of [M] ⁺ of each precursor in which n is 0 to 8). Further, for example, the sum B of the composition ratios of the respective components having n of 3 to 6 is B (%) = 100 × (the sum of [M] ⁺ of each precursor having n of 3 to 6) / (n is 0 to 0). The total of [M] ⁺ of each of the 8 precursors).

  A mixture in which the sum of the composition ratios of n = 3-6 diimonium compounds calculated from the peak intensity of the mass spectrum is 70% or more and 98% or less of the total (total of each diimonium compound where n is 0-8). Is a more preferred mixture for the purposes of the present invention. Such a composition can be easily prepared by adjusting the amount of the alkylating agent added, the reaction temperature, and the reaction time.

  The “diimonium mixture” used in the present invention may be used alone, but in order to adjust the desired near-infrared absorption wavelength region and absorption ratio, one or more other near-infrared absorbing compounds and Specific examples of other near-infrared absorbing compounds that may be used in combination include diimonium compounds other than "the present diimonium mixture", nitroso compounds and their metal salts, cyanine compounds, squarylium compounds, thiol nickel complex salts Examples thereof include compounds, phthalocyanine compounds, naphthalocyanine compounds, triallylmethane compounds, naphthoquinone compounds, and anthraquinone compounds. In the present invention, it is preferable to select and use a compound having a maximum absorption at a wavelength of 800 to 1100 nm from these compounds.

Hereinafter, a method for forming a near-infrared absorbing film by forming a layer containing “the present diimonium mixture” on a transparent support film will be described. In the case of using a near-infrared absorbing compound other than “the present diimonium mixture”, a method of mixing and coating in the same coating liquid as “the present diimonium mixture” is advantageous, but a known method as a separate layer Can also be held on the same transparent support film.

  As a method of holding the “diimonium mixture” on the transparent support film, a coating layer (hereinafter referred to as a binder resin layer) is formed using a binder resin, and the coating layer is contained in the coating layer and the adhesive layer. A method is mentioned as a preferable method.

The type and thickness of the transparent support film used in the present invention is not particularly limited as long as it is highly transparent, hardly scratched, and can withstand use as an optical film, but the thickness is 10 to 500 μm. Workability is good and preferable, and the type of film includes polyester-based, polycarbonate-based, triacetate-based, norbornene-based, acrylic-based, cellulose-based, polyolefin-based or urethane-based polymer resin films, transparency, etc. Polyethylene terephthalate (hereinafter referred to as “PET”) is preferred from the standpoint of the physical properties and availability of the optical film. A transparent support film containing an ultraviolet absorbing substance can be used to absorb the ultraviolet rays from the outside and stabilize the function of the internal member, and the film surface has good adhesion to the coating film. In order to increase, easy adhesion may be improved by applying a corona discharge treatment, a plasma treatment, a glow discharge treatment, a roughening treatment, a chemical treatment, an anchor coating agent, a primer or the like.
In addition, the transparent support film has a function of having one or more functions such as anti-reflection, anti-glare / anti-reflection, antistatic, antifouling, neon light absorption, electromagnetic shielding or color adjustment. Transparent support films may be used, and in particular, when the present dimonium mixture is included in the adhesive layer of these functional transparent support films, an optical film having these functions and near-infrared absorptivity at the same time is obtained. Therefore, a rational and excellent form optical filter is possible, and the use of a functional transparent support film is an advantageous choice. As the functional transparent support film, a transparent support film having a reduced reflection function or an electromagnetic wave shielding function is preferable.

Next, although the example of an above described preferable functional transparent support film is demonstrated, the kind of transparent support film which has functionality is not limited to these.
Transparent support film (decrease reflection film) having a function of reducing reflection is a film that suppresses reflection of light from the outside by coating the surface of a transparent support film such as PET with a low refractive index agent together with a binder resin and other additives. Alternatively, a hard coat layer and a high refractive index layer are provided between the transparent support film and the low refractive index layer, and the visibility is improved by controlling the reflected light from each layer to cancel each other. The film is a film in which fine particles are contained in the high refractive index layer or hard coat layer of the anti-reflection film to diffuse the light from the outside to improve visibility. These films can be easily obtained from the market as the Arktop series (Asahi Glass), Kayacoat ARS series (Nippon Kayaku), Kayacoat AGRS series (Nippon Kayaku), Realak series (Nippon Yushi). It is.

  Next, in a transparent support film (electromagnetic wave shielding film) having an electromagnetic wave shielding function, a method of shielding electromagnetic waves is a mesh type in which fine wires of metal such as copper are held on a transparent support film in a geometric pattern like a mesh. In addition, there is a thin film type in which a metal ultrathin film is held on a transparent base film within a range having light transmittance. However, in the PDP, when a thin film type is used (in general, near infrared rays are reflected). Does not transmit) and does not require a near-infrared absorbing film. Therefore, in the present invention, when an electromagnetic wave shielding film is used, it is preferable to use a mesh type electromagnetic wave shielding film as a transparent support film. In addition, when a film having an anti-reflection and electromagnetic wave shielding property obtained by applying an electromagnetic wave shielding layer in a mesh shape by screen printing or the like on the opposite surface of the anti-reflection surface of the anti-reflection film is used as a transparent support film It is convenient for producing an optical filter for PDP.

  As the transparent support film having other functionalities that can be used in the present invention, neon light absorbability, ultraviolet light absorbability, antistatic properties, antifouling properties, color adjustment, and the like are retained alone or in plural. Although there exists a transparent support film, these can be produced according to a method known per se by a method of molding from a binder resin composition containing each compound having these properties.

  First, a method for incorporating the “diimonium mixture” into the adhesive layer will be described. The resin that is the main component of the adhesive layer is not particularly limited as long as it can uniformly disperse the “diimonium mixture”, forms a transparent layer on the surface of the transparent support film, and does not impair the function as an optical film. -Based, polyester-based, polyamide-based, polyurethane-based, polyolefin-based, polycarbonate-based, rubber-based or silicone-based adhesive materials, etc., and acrylic resin adhesive in terms of excellent transparency, adhesiveness, heat resistance, etc. A material is preferred. Acrylic resin adhesive is mainly composed of acrylic acid alkyl ester having no functional group (excluding double bond), and other than acrylic acid alkyl ester and acrylic acid alkyl ester having functional group in this. A monomer component is copolymerized. The copolymerization ratio of other monomer components other than the acrylic acid alkyl ester having the functional group and the acrylic acid alkyl ester is 0.1 to 20 per 100 parts by weight of the acrylic acid alkyl ester component having no functional group. Part by weight, more preferably 1 to 10 parts by weight.

  Examples of the acrylic acid alkyl ester having no functional group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, (meth Alkyl) such as hexyl acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate or dodecyl (meth) acrylate Examples thereof include alkyl acrylates or methacrylic acid alkyl esters having 1 to 12 carbon atoms, and these may be used in combination of two or more.

  As a monomer other than an acrylic acid alkyl ester having a functional group or an acrylic acid alkyl ester, one that functions as a crosslinking point with a crosslinking agent to be described later is used, and the type thereof is not particularly limited. Hydroxy group-containing (meth) acrylic acid ester monomers such as 2-hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate, N, N-dimethylaminoethyl acrylate, N-tert-butylaminoethyl acrylate, etc. These amino group-containing (meth) acrylic acid monomers, acrylic acid, maleic acid and the like may be mentioned, and these may be used in combination of two or more.

  The pressure-sensitive adhesive is preferably used in a composition that can crosslink the acrylic resin and the like by blending a crosslinking agent. As a crosslinking agent, it is suitably used according to the kind of the above-mentioned monomer. Polyisocyanate compounds such as aromatic diisocyanates, butyl etherified styrol melamine, melamine compounds such as trimethylol melamine, diamine compounds such as hexamethylenediamine or triethylenediamine, epoxy resin compounds such as bisphenol A and epichlorohydrin, urea resin systems A compound, a metal salt such as aluminum chloride, ferric chloride, or aluminum sulfate is used, and its blending amount is usually 100% acrylic resin adhesive. 0.005 parts by weight per volume parts, preferably 0.01 to 3 parts by weight.

  The above acrylic resin adhesives are excellent in adhesive strength and cohesive strength, and since they have no unsaturated bonds in the crosslinked polymer, they are highly stable against light and oxygen, and the type and molecular weight of the monomer can be freely selected. It is also preferable because the degree of polymerization is high, and in order to maintain adhesion to the transparent support film, the molecular weight (degree of polymerization) is high, that is, the weight average molecular weight (Mw) of the main polymer is preferably about 600,000 to 2,000,000. More preferably, it is about 800,000 to 1,800,000.

  In PDP, orange neon light having a wavelength of 550 to 620 nm derived from neon gas generated at the time of applied voltage needs to be cut to some extent in front of the display in order to reduce the color purity of red light. Although a neon light absorption filter held in a film is usually used, a method of obtaining a layer capable of absorbing near infrared rays and neon light simultaneously by incorporating a compound having neon light absorption ability into a layer having near infrared absorption ability Is advantageous. Here, examples of neon light absorbing compounds that can be used include compounds such as azaporphyrin, cyanine, squarylium, azomethine, xanthene, oxonol, or azo, particularly in the adhesive layer. Therefore, it is necessary to give sufficient consideration to the “thermal stability” of the “diimonium mixture” used. For example, tetraazaporphyrin-based compounds are relatively stable, and other compounds can be used if they are stabilized.

  “This dimonium mixture” is used for the above-mentioned pressure-sensitive adhesive, which is the main component of the pressure-sensitive adhesive, a polymerization initiator, a crosslinking agent, an ultraviolet absorber, a color-adjusting dye, and other necessary additives such as electromagnetic shielding meshes. In the case of discoloration due to contact with metal, the layer thickness after drying on the surface of the transparent support film is obtained by sufficiently dissolving or dispersing it in a solvent such as methyl ethyl ketone (MEK) together with an antioxidant and a rust inhibitor. Is 5 to 100 μm, preferably 10 to 50 μm. The coating method is not particularly limited, and is a method of applying with a bar coater, reverse coater, comma coater or gravure coater, and drying and adhering the adhesive layer, or applying an adhesive solution on the release film to a bar coater or reverse coater For example, there may be mentioned a method in which a pressure-sensitive adhesive layer is transferred onto a transparent support film after being applied with a comma coater, a gravure coater or the like and dried. The amount of solvent to be used varies depending on the coating method, but when an acrylic resin adhesive having a main polymer weight average molecular weight of around 1 million is used and applied with a comma coater, the adhesive is 10 to 25% by weight. Thus, it is preferable to dilute with a solvent. The near-infrared absorbing film of the present invention is preferably designed so that the transmittance of near-infrared light having a wavelength of 800 to 1100 nm is 10% or less, and “the present diimonium mixture” may be used in an amount corresponding thereto, What is necessary is just to contain so that it may become 1 to 20 weight% in general with respect to a layer.

  “This dimonium mixture” is a mixture of two or more kinds of dimonium compounds. However, in a single product of dimonium compounds having 8 normal propyl groups (n = 8 in formula (1)), it is frequently used as a solvent for coating. Insufficient solubility in solvents such as MEK tends to form aggregates on the coated surface, and the near infrared absorptivity tends to be poor. As n becomes larger, that is, as the ratio of the diimonium compound having a large number of normal propyl groups becomes higher, the solvent solubility becomes inferior and the coating becomes difficult. Further, when all of the eight are isobutyl groups (n = 0 in the formula (1)), the near-infrared absorption ability is slightly inferior to that of the “present dimonium mixture” and the haze value is also higher. The haze value tends to increase as the content ratio of the diimonium compound having a small n, that is, a large number of isobutyl groups, increases. From the above, the “present dimonium mixture” is superior in terms of physical properties or ease of handling than using a single product having 8 normal propyl groups and 8 isobutyl groups. Mixtures of compounds that are not too biased in either direction are more suitable, and the sum of the composition ratios of the diimonium compounds having n of 3 to 6 calculated from the peak intensity of the mass spectrum described above is the total (where n is the composition ratio of 0 to 8). A mixture that is 70% or more and 98% or less of the total) is more preferable.

Next, a method for holding the “present dimonium mixture” as a binder resin layer on the transparent support film will be described.
`` This dimonium mixture '' is mixed with a binder resin and, if necessary, a neon light absorbing dye, a color adjusting dye, a leveling agent, an antistatic agent, an antioxidant, a dispersant, a flame retardant, a lubricant, a plasticizer, an ultraviolet absorber, In addition, it is possible to employ a method of dissolving and / or dispersing in a solvent together with additives and the like to form a coating liquid, coating with a coating machine, and drying. In addition, when a binder resin such as thermosetting or active energy ray curable is used, a curing step is required after drying. However, near infrared and neon light absorbing compounds are deteriorated by curing heat and active energy rays. As a result, it is desirable to use a thermoplastic binder resin unless there are special circumstances.

  The binder resin is easy to apply, has good adhesion to a transparent support film, has good visible light transmission properties, and is not particularly limited as long as there is no problem with the surface quality, etc., but polyester resins and acrylic resins are easy to handle. It is preferably selected from thermoplastic resins such as polyamide resins, polyurethane resins, polyolefin resins or polycarbonate resins. After coating and winding up into a roll, it has a glass transition temperature and other physical properties that do not cause problems such as blocking during storage, and the "thermal stability" of the "diimonium mixture" used It is preferable to select a material that does not adversely affect the material.

  Examples of the solvent include alcohols such as methanol, ethanol, isopropanol, diacetone alcohol, ethyl cellosolve or methyl cellosolve, ketones such as acetone, methyl ethyl ketone (MEK), cyclopentanone or cyclohexanone, N, N-dimethylformamide or N Amides such as N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane or ethylene glycol monomethyl ether, esters such as methyl acetate, ethyl acetate or butyl acetate, chloroform, methylene chloride, dichloroethylene or Aliphatic hydrocarbons such as trichloroethylene, aromatics such as benzene, toluene, xylene, monochlorobenzene or dichlorobenzene, or n-hexane Aliphatic hydrocarbons such as n-heptane, fluorine-based solvents such as tetrafluoropropyl alcohol or pentafluoropropyl alcohol, etc. can be used, and the solubility in each material is high, and there is no inconvenience in coating, drying, It is preferable to select a solvent that does not have a safety problem.

  Of the additives used as necessary, the neon light absorbing compound is the same as that used in the above-mentioned adhesive layer, and other additives are used in the “heat of the present diimonium mixture”. It is used by being included in the solution while taking into consideration the “stability” and the desired quality performance.

  Coating of the coating liquid is a known coating method such as a flow coating method, a spray method, a bar coating method, a gravure coating method, a roll coating method, a blade coating method, an air knife coating method, a lip coating method or a die coater method. Thus, the finished layer thickness is usually 0.1 to 30 μm, preferably 0.5 to 10 μm, and the treatment layer is fixed by drying. In addition, when hardening is needed separately, after drying, a hardening process is performed and a process layer is fixed. The near-infrared shielding property is preferably designed so that the transmittance of near-infrared light having a wavelength of 800 to 1100 nm is 10% or less, as in the case where the present layer contains the “diimonium mixture”. The amount of solvent used varies depending on the coating method, but when using a thermoplastic acrylic resin binder having a weight average molecular weight of about 300,000 of the main polymer and coating with a micro gravure coater, it will be 15 to 30% by weight. It is preferable to dilute with a solvent.

  When the diimonium compound is contained in the binder resin layer, the most commonly used diimonium compound having an anion of hexafluoroantimonate ion, such as Kayasolv IRG-022 (trade name; manufactured by Nippon Kayaku Co., Ltd.) and many As described in Patent Document 3, the use of a binder resin having a low Tg of 85 ° C. or lower results in poor “thermal stability”, but the “diimonium mixture” uses a binder resin having a temperature of 85 ° C. or lower. There is no problem, and it is not necessary to manage the amount of residual solvent in the binder resin layer as disclosed in Patent Document 3, and it can be used without any problem even in drying under normal drying conditions. In addition, “the present diimonium mixture” in the above formula (1) is easy to handle because it has superior solvent solubility compared to a single product in which all substituents are normal propyl groups (n = 8). "" Can also obtain an excellent near-infrared-absorbing film by the method of containing it in the binder resin layer.

  Next, the optical filter of the present invention has the following functions with the near-infrared absorbing film of the present invention in which the layer containing the “diimonium mixture” is provided on the transparent support film as a minimum component. It is obtained by laminating or pasting the transparent support film having. The preferred use of these optical filters is for PDP, and the optical filter of the present invention is used by pasting directly on the front surface of the PDP even if it is pasted on a transparent glass plate or plastic plate and attached to the front surface of the PDP. May be.

Examples of configurations of various films in the optical filter of the present invention include the following (1) to (13).
In the following description, NIRA represents near-infrared absorptivity, NeA represents neon light absorptivity, and the portion enclosed in braces ({}) encloses the near-infrared absorbing film of the present invention in parentheses (()). A part shows each functional film other than this invention. As is apparent from these structural examples, for example, by adding “this diimonium mixture” or a neon light absorbing compound to the adhesive layer of a transparent support film having functionality such as a low-reflection transparent support film, It is possible to produce an optical filter for PDP simply by pasting the film. Furthermore, by providing a film with electromagnetic shielding of the mesh on the back surface of the anti-reflection film as a transparent support film, by providing a binder resin layer or an adhesive layer containing “the present diimonium mixture” and a neon light absorber on the mesh surface, It is also possible to manufacture an optical filter for PDP with one kind of film. As an optical filter of the present invention, an embodiment including the near-infrared absorbing film of the present invention and a film having an electromagnetic wave shielding ability or a film having a function of reducing reflection is preferable.

(1) {Non-reflective film / NIRA / NeA / color adjusting adhesive layer} / (electromagnetic wave shielding film / adhesive layer),
(2) {Non-reflective film / NIRA / color adjusting adhesive layer} / (electromagnetic wave shielding film / NeA adhesive layer),
(3) (anti-reflection film / adhesive layer) / {electromagnetic wave shielding film / NIRA / NeA / color adjusting adhesive layer},
(4) {Anti-glare / anti-reflection film / NIRA / NeA / color adjusting adhesive layer} / (electromagnetic wave shielding film / adhesive layer),
(5) (Non-reflective film / adhesive layer) / {NIRA / NeA binder resin layer / PET / color adjusting adhesive layer} / (electromagnetic wave shielding film / adhesive layer),
(6) (Non-reflective film / adhesive layer) / {NeA film / NIRA / color adjusting adhesive layer} / (electromagnetic wave shielding film / adhesive layer),
(7) (Non-reflective film / adhesive layer) / (electromagnetic wave shielding film / adhesive layer) / {NeA film / NIRA / color adjusting adhesive layer},
(8) (Non-reflection film / adhesive layer) / (electromagnetic wave shielding film) / {NIRA / NeA absorbing adhesive layer / PET / color adjusting adhesive layer},
(9) (anti-reflection film / adhesive layer) / {NIRA / NeA binder resin layer / PET / color adjusting adhesive layer} / (electromagnetic wave shielding film / adhesive layer),
(10) {Non-reflection film / NIRA / NeA binder resin layer / color adjusting adhesive layer} / (electromagnetic wave shielding film / adhesive layer)
(11) {Non-reflection film / NIRA / NeA binder resin layer / color adjusting adhesive layer} / (electromagnetic wave shielding film / adhesive layer)
(12) {Non-reflection film / Electromagnetic wave shielding layer / NIRA binder resin layer / NeA adhesive layer}
(13) {Anti-reflection film / electromagnetic wave shielding layer / NIRA / NeA adhesive layer}

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the examples. In Examples, “part” means “part by weight” and “%” means “% by weight”.

Synthesis example 1
(Substitution reaction)
7 parts of N, N, N ′, N′-tetrakis (aminophenyl) -p-phenylenediamine, 27 parts of potassium carbonate, 14.8 parts of potassium iodide, 32 parts of isobutyl bromide, 1-bromopropane 3 in 100 parts of DMF Part was added and reacted at 90 ° C. for 2 hours and then at 110 ° C. for 6 hours. After cooling, the precipitated crystals are separated by filtration, and the obtained crystals are dissolved in hot DMF. After removing the insoluble matter, methanol was added to the solution, and the precipitated crystals were separated by filtration, washed with water, dried, and a precursor of light green crystals (see formula (3) above) 6.8 Got a part.
(Oxidation reaction)
5 parts of the above precursor crystals are added to 40 parts of DMF, and heated and dissolved at 60 ° C., then 9 parts of a 58% aqueous solution of tris (trifluoromethanesulfonyl) carbonic acid is added, and then 1.9 parts of silver nitrate dissolved in 30 parts of DMF are added. In addition, it was heated and stirred for 30 minutes. After filtering the insoluble matter, water was added to the reaction solution, and the resulting crystals were filtered, washed with water and dried to obtain 5.2 parts of a mixture of diimonium compounds. Calculation of the composition ratio of each component in this mixture was performed by the method described above, and the results are shown in Table 1. The maximum absorption wavelength of this mixture was 1107 nm (dichloromethane).

Synthesis example 2
(Substitution reaction)
A substitution reaction and purification were carried out in the same manner as in Synthesis Example 1 except that 3 parts of 1-bromopropane in Synthesis Example 1 were replaced with 7.3 parts to obtain 6.5 parts of a light green crystal precursor.
(Oxidation reaction)
An oxidation reaction and purification were performed in the same manner as in Synthesis Example 1 except that the precursor obtained in Synthesis Example 1 was replaced with the above precursor to obtain 4.5 parts of a mixture of diimonium compounds. Calculation of the composition ratio of each component in this mixture was performed by the method described above, and the results are shown in Table 1. The maximum absorption wavelength of this mixture was 1092 nm (dichloromethane).

Synthesis example 3
(Substitution reaction)
A substitution reaction and purification were carried out in the same manner as in Synthesis Example 1 except that 3 parts of 1-bromopropane in Synthesis Example 1 were replaced with 10 parts to obtain 6.2 parts of a light green crystal precursor.
(Oxidation reaction)
An oxidation reaction and purification were performed in the same manner as in Synthesis Example 1 except that the precursor of Synthesis Example 1 was replaced with the above precursor, to obtain 6.1 parts of a mixture of diimonium compounds. Calculation of the composition ratio of each component in this mixture was performed by the method described above, and the results are shown in Table 1. The maximum absorption wavelength of this mixture was 1103 nm (dichloromethane).

Synthesis example 4
(Substitution reaction)
A substitution reaction and purification were carried out in the same manner as in Synthesis Example 1 except that 3 parts of 1-bromopropane in Synthesis Example 1 was added instead of 12.7 parts to obtain 7.6 parts of a light green crystal precursor. .
(Oxidation reaction)
An oxidation reaction and purification were performed in the same manner as in Synthesis Example 1 except that the precursor of Synthesis Example 1 was replaced with the above precursor, to obtain 5.4 parts of a mixture of diimonium compounds. Calculation of the composition ratio of each component in this mixture was performed by the method described above, and the results are shown in Table 1. The maximum absorption wavelength of this mixture was 1101 nm (dichloromethane).

  Table 1 summarizes the ratio of each component in the mixture of diimonium compounds obtained in Synthesis Examples 1 to 4.

(Solvent solubility)
The solvent solubility of the diimonium compound obtained in Synthesis Examples 1 to 4 and the diimonium compound used in Comparative Examples 1, 2, and 3 below was measured by the following method.
A 5% methyl ethyl ketone solution of the target dimonium compound was prepared at room temperature, and the dissolved state was observed. As a result, the diimonium compound used in Synthesis Examples 1 to 4 and Comparative Examples 2 and 3 was in a transparent state, whereas the diimonium compound used in Comparative Example 1 was not completely dissolved, and a precipitate was observed. .

Example 1
(Preparation of near-infrared absorbing film 1)
Apply a coating solution prepared by mixing and dissolving the raw materials shown in Table 2 below uniformly on MRF-75 (trade name, PET release film, manufactured by Mitsubishi Chemical Polyester Film) with a comma coater. The pressure-sensitive adhesive layer was formed by coating so that the thickness of the pressure-sensitive adhesive layer was 18 μm at a processing speed and a drying temperature of 110 ° C. Next, the PET release film provided with the adhesive layer is pressure-bonded with a roll on the opposite side of the anti-reflection surface of KAYACOAT ARS-D501 (trade name, anti-reflection film, manufactured by Nippon Kayaku Co., Ltd.). The near-infrared absorbing film 1 of the present invention having neon light was obtained.

(Ii) TAP-2; tetraazaporphyrin-based compound, tinuvin 109; benzotriazole-based compound, coronate HL; isocyanate-based curing agent

Example 2
(Preparation of near-infrared absorbing film 2)
The present invention absorbs neon light and has a low reflection property in the same manner as in Example 1 except that the mixture of the diimonium compound of Synthesis Example 2 is used instead of the mixture of the diimonium compound of Synthesis Example 1 of Example 1. No near infrared absorption film 2 was obtained.
(Preparation of optical filter 1 for PDP)
The protective film of ES-1534U (HCD-42-02) A (trade name, electromagnetic wave shielding film, manufactured by Hitachi Chemical Co., Ltd.) is peeled off, and the near-infrared absorbing film 2 is bonded thereon via an adhesive layer. An optical filter for PDP of the present invention was obtained. Even if this filter is directly attached to the front surface of the PDP module or attached to a glass plate (transparent plate) and attached in front of the module, the filter exhibits sufficient performance as an optical filter for PDP.

Example 3
(Preparation of near-infrared absorbing film 3)
The present invention absorbs neon light in the same manner as in Example 1 except that the mixture of the diimonium compound of Synthesis Example 3 is used instead of the mixture of the diimonium compound of Synthesis Example 1 of Example 1. The near-infrared absorbing film 3 was obtained.
(Production of optical filter 2 for PDP)
The protective film of ES-1534U (HCD-42-02) A (trade name, electromagnetic wave shielding film, manufactured by Hitachi Chemical Co., Ltd.) is peeled off, and the near-infrared absorbing film 3 is bonded thereon via an adhesive layer. An optical filter for PDP of the present invention was obtained. Even if this filter is affixed directly to the front surface of the PDP module via an adhesive layer of an electromagnetic wave shielding film, or is attached to the front of the module by attaching it to a glass plate, the filter can sufficiently perform the performance required as an optical filter for PDP. there were.

Example 4
(Preparation of near-infrared absorbing film 4)
The present invention absorbs neon light and has a low reflection property in the same manner as in Example 1 except that the mixture of the diimonium compound of Synthesis Example 4 is used instead of the mixture of the diimonium compound of Synthesis Example 1 of Example 1. The near-infrared absorbing film 4 was obtained.

Example 5
(Preparation of near-infrared absorbing film 5)
In 40 parts of MEK, 0.5 part of the mixture of the diimonium compound of Synthesis Example 2 and 37 parts of foret PAN-125 (trade name, acrylic binder resin having a Tg of 70 ° C., manufactured by Soken Chemical Co., Ltd.) were dissolved to obtain a coating solution. . This coating solution was applied onto Cosmo Shine A4300 (trade name, polyester film with a thickness of 100 microns, manufactured by Toyobo Co., Ltd.) with a micro gravure coater using a micro gravure roll at a line speed of 10 m / min. It dried at ° C and obtained the near-infrared absorption film 5 of this invention which contains the mixture of the diimonium compound of the synthesis example 2 in a binder resin layer.

Comparative Example 1
In the same manner as in Synthesis Example 1, except that 32 parts of isobutyl bromide in Synthesis Example 1 and 14.7 parts of 1-bromopropane were used, 4 substituents in Formula (1) were used. A comparative near-infrared absorbing film was obtained in the same manner as in Example 1 except that a diimonium compound which was all normal propyl group was prepared and used instead of the mixed part of the diimonium compound of Synthesis Example 1.

Comparative Example 2
Except for using 32 parts of isobutyl bromide of Synthesis Example 1 and 44.7 parts of isobutyl bromide instead of 12.7 parts of 1-bromopropane, all 8 substituents in Formula (1) are isobutyl in the same manner as in Synthesis Example 1. A comparative near-infrared absorbing film was obtained in the same manner as in Example 1 except that a base diimonium compound was prepared and used instead of the mixed portion of the diimonium compound of Synthesis Example 1.

Comparative Example 3
Similar to Example 5 except that the same amount of Kayasolv IRG-022 (trade name, diimonium compound of antimony hexafluoride anion, manufactured by Nippon Kayaku Co., Ltd.) was used instead of the mixture of diimonium compounds of Synthesis Example 2 of Example 5. The comparative near-infrared absorption film which contains a near-infrared absorber in a binder resin layer by the method was obtained.

Performance test (1) (Near-infrared absorbing film containing a near-infrared absorber in the adhesive layer)
When the test pieces of the near-infrared absorbing film obtained in Examples 1 to 4 and the comparative near-infrared absorbing film obtained in Comparative Examples 1 and 2 were stored in a thermostat at 80 ° C. for 500 hours, Changes in transmittance, luminous transmittance (Y%) and chromaticity coordinates (x, y) at each maximum absorption wavelength were measured, and the heat resistance of each test piece was compared. The transmittance is measured with UV-3150 (trade name, spectrophotometer, manufactured by Shimadzu Corporation), and the luminous transmittance and chromaticity coordinates (x, y) are determined based on the XYZ color system of JIS Z 8701. It was calculated in accordance with the color display method. The haze value was measured by TC-H3DPK (trade name, haze meter, manufactured by Tokyo Denshoku Technology Center). Furthermore, the appearance change was observed with the naked eye.
The results of the performance test (1) are summarized in Table 3.

(Consideration) Comparative Example 1 using a diimmonium compound in which n is 8 in the formula (1) has a high haze value, and aggregates are also formed. Moreover, the comparative example 2 which uses the diimonium compound whose n is 0 in the said Formula (1) was inferior in haze value, and the near-infrared absorptivity was also inferior. In contrast, the near-infrared absorbing films of Examples 1 to 4 using a mixture of two or more kinds of diimmonium compounds having different n values in the present invention were practical results in all items. The near-infrared absorbing films of Examples 2 to 4 each having a mixture of diimonium compounds in which the sum of each component having n of 3 to 6 is 70% or more in the adhesive layer are 70% or less in haze value and near-infrared shielding rate (Example 1). In addition, the test results in the heat and humidity resistance (60 ° C., RH 90%, 500 hours) were almost the same as described above. The results of heat and humidity resistance are summarized in Table 4.

Performance test (2) (Near-infrared absorbing film containing near-infrared absorber in binder-resin layer)
About each test piece of the near-infrared absorption film obtained by Example 5 (this invention) and the comparative near-infrared absorption film obtained by the comparative example 3, the performance test (heat resistance similar to the case of a performance test (1)) The results shown in Table 5 were obtained.

(Consideration) In the heat resistance test, the transmittance of near infrared rays is 10% or less, but Comparative Example 3 has a large change in transmittance. In the chromaticity coordinates, Example 5 had little change despite the low Tg of the binder resin of 70 ° C., and there was no change in appearance, but Comparative Example 3 was greatly affected by Tg and the change in y of the chromaticity coordinates was large. Appearance changed, yellowish. In addition, the test results in the heat and humidity resistance (60 ° C., RH 90%, 500 hours) were almost the same as described above. The results of moisture and heat resistance are summarized in Table 6.

Claims (8)

A near-infrared absorbing film, wherein a mixture of two or more diimonium compounds represented by the following formula (1) and having different n is contained in a layer formed on a transparent support film.

(In Formula (1), n-Pr represents a normal propyl group, iso-Bu represents an isobutyl group, and n represents an integer of 0 to 8.)   The mixture of two or more kinds of diimonium compounds having different n in formula (1) contains 70% (calculated from mass spectrum) or more and 98% or less of diimonium compounds in which n is 3 to 6 in formula (1) Item 2. The near-infrared absorbing film according to Item 1.   The near-infrared absorbing film according to claim 1 or 2, wherein the layer formed on the transparent support film is an adhesive layer.   The layer formed on the transparent support film contains a mixture of two or more diimonium compounds having different n in formula (1) and a compound having a maximum absorption at a wavelength of 550 to 620 nm. The near-infrared absorption film as described in any one of Claims.   The near-infrared absorbing film according to any one of claims 1 to 4, wherein the transparent support film is a film having a reduced reflection function or an electromagnetic wave shielding function.   The optical filter for plasma display panels containing the near-infrared absorption film as described in any one of Claims 1 thru | or 5.   The optical filter for a plasma display panel according to claim 6, comprising the near-infrared absorbing film according to any one of claims 1 to 5, a film having an electromagnetic wave shielding ability and / or a film having a function of reducing reflection. . A mixture of two or more diimonium compounds represented by formula (1) and different n.

(In formula (1), n-Pr represents a normal propyl group, iso-Bu represents an isobutyl group, and n represents an integer of 0 to 8).