HK1129733B - Near infrared ray absorbing film and optical filter for plasma display panel using the same - Google Patents

Description

Near infrared ray absorbing film and filter for plasma display panel using the same

Technical Field

The present invention relates to a near-infrared ray absorption film using a diimmonium compound which greatly absorbs light having a wavelength in the near-infrared ray region and is excellent in heat resistance, moist heat resistance, solvent solubility and the like, and an optical filter for a plasma display panel (hereinafter referred to as PDP) using the film.

Background

Since the near infrared rays are used as rays when electrical equipment is operated from a long distance, there is a possibility that the equipment which emits the near infrared rays may malfunction the electrical equipment installed in the surroundings, and a filter or the like having a function of shielding the near infrared rays needs to be installed in front of the equipment (for example, PDP).

The principle of the PDP is that a voltage is applied to a rare gas (neon, xenon, etc.) sealed in a discharge cell sandwiched by 2 plate-shaped glasses, and ultraviolet rays emitted from the rare gas in a plasma state are brought into contact with a light-emitting body coated on a wall surface of the discharge cell to generate visible light necessary for an image, but electromagnetic waves harmful to humans, electrical equipment, etc. such as orange light (hereinafter, referred to as neon light) having a wavelength around 595nm, which degrades the optical purity of red light due to near infrared rays, electromagnetic waves, and neon gas, are also emitted together with the visible light, and therefore, harmful electromagnetic waves typified by near infrared rays must be shielded while transmitting useful visible light, and a filter having such a function is required in the PDP.

The near-infrared ray absorption film used in the filter is used for shielding near-infrared rays, and a compound having a function of absorbing near-infrared rays (near-infrared ray absorbing compound) is used. That is, the near infrared ray absorption film is produced by incorporating these near infrared ray absorbing compounds into a layer provided on the surface of a transparent support film (a transparent functional film such as a transparent base film, an antireflection film, or a film for shielding electromagnetic waves harmful to the human body (hereinafter referred to as an electromagnetic wave shielding film)). Some of the near-infrared absorbing compounds used in the present invention are, but most of them are, for example, diimmonium compounds having a wide near-infrared absorption wavelength range, which are used alone, or in combination with 1 or more other near-infrared absorbing compounds based on a diimmonium compound. However, many compounds having near infrared absorption are insufficient in heat stability and resistance to moist heat stability (hereinafter, both are simply referred to as "heat stability"), and the same applies to diimmonium compounds. Further, as the diimmonium compound, a diimmonium compound having hexafluoroantimonate ion is generally used, but the compound is a toxic substance, and due to environmental problems, the use restriction of heavy metals and the like becomes more and more strict, and the like, a safer diimmonium compound is desired. As a method for solving the above problems, 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, but the "thermal stability" is still insufficient, and in particular, a near-infrared ray absorption film containing these compounds in an adhesive layer has problems such as discoloration of a layer containing these compounds and deterioration of near-infrared ray absorption properties.

As main specific methods for holding the near-infrared ray absorbing compound on the transparent support film, the following 2 methods can be cited: a method of forming a polymer resin layer by dissolving and/or dispersing the resin in a solvent together with a binder resin and coating the resin on a transparent resin film; a method of incorporating the same in an adhesive layer. The former method is characterized in that "thermal stability" is easily affected by the glass transition temperature of the binder resin used and the amount of residual solvent of the resin layer, while the latter method is characterized in that "thermal stability" is easily lowered, and there is a possibility that haze value and visible light transmittance, which are one of the criteria of transparency, are adversely affected.

As a technique for stabilizing a diimmonium compound in a layer (a layer provided using a polymer resin such as a top coat layer, an adhesive layer, and a treatment layer) provided on a transparent support film, patent document 3 discloses a technique for stabilizing a diimmonium compound by controlling the amount of a solvent remaining in a layer provided on a transparent support film to a predetermined ratio or less, or by using a binder resin having a high glass transition temperature. In addition, there has been no report on a method for effectively preventing adverse effects on the haze value and the visible light transmittance when a diimmonium compound is contained in an adhesive layer provided on a transparent support film.

In summary, a simple technique for producing a near-infrared ray absorption film having excellent performance as an optical filter using a diimmonium compound having a good near-infrared ray absorption ability without affecting the near-infrared ray absorption ability and the "thermal stability" thereof and without limiting the binder resin used is desired.

Patent document 1: japanese patent laid-open publication No. 10-316633 (page 5)

Patent document 2: japanese patent publication No. Hei 7-51555 (page 2)

Patent document 3: japanese patent laid-open No. 2000-227515

Patent document 4: japanese patent Japanese Kokoku publication Sho 43-25335 (pages 7-14)

Disclosure of The Invention

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a diimmonium compound having a wide absorption wavelength range in the near infrared region, which is easily handled due to its good solubility in solvents, can be used in a wide range of glass transition temperature (hereinafter referred to as Tg) of a binder resin, can maintain excellent thermal stability even when contained in an adhesive layer, can efficiently absorb near infrared rays, can secure a lower haze value, and can be synthesized at low cost, and an optical filter having excellent performance using the diimmonium compound.

The present inventors have conducted intensive studies to solve the above problems and, as a result, have found that: the above-mentioned technical problems can be solved by a mixture of diimmonium compounds having a specific substituent on the cation side and a specific anion selected, thereby completing the present invention.

That is, the present invention relates to

(1) A near-infrared ray absorption film characterized in that a layer formed on a transparent support film contains a mixture of 2 or more kinds of diimmonium compounds having different n, which are represented by the following formula (1),

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

(2) The near-infrared ray absorption film according to (1), wherein the mixture of 2 or more kinds of diimmonium compounds having different n in the formula (1) contains 70% (calculated from mass spectrum) to 98% of the diimmonium compound having n of 3 to 6 in the formula (1).

(3) The near-infrared ray absorption film according to (1) or (2), wherein the layer formed on the transparent support film is an adhesive layer.

(4) The near-infrared ray absorption film as described in any one of (1) to (3), wherein a mixture of 2 or more kinds of diimmonium compounds having different n of the formula (1) and a compound having an absorption maximum at a wavelength of 550 to 620nm are contained in a layer formed on the transparent support film.

(5) The near-infrared ray absorption film as described in any one of (1) to (4), wherein the transparent support film is a film having an antireflection function or an electromagnetic wave-shielding function.

(6) An optical filter for a plasma display panel, comprising the near-infrared ray absorption film according to any one of (1) to (5).

(7) The filter for a plasma display panel according to (6), which comprises the near infrared ray absorption film of any one of (1) to (5) and a film having an electromagnetic wave shielding ability and/or a film having an antireflection function.

(8) A mixture of 2 or more diimmonium compounds represented by the formula (1) wherein n is different,

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

The mixture of diimmonium 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 toxic substance, and has good solvent solubility, thus being easy to handle, and the near infrared ray absorption film obtained therefrom well absorbs near infrared rays in the wavelength region of 800 to 1100nm, exhibits excellent haze and "thermal stability" even if contained in an adhesive layer, and does not suffer from deterioration of near infrared ray absorption, discoloration of the layer, deterioration of surface quality, etc., and a filter for PDP obtained by compounding the near infrared ray absorption film with other functional films has excellent performance, and can satisfactorily solve the above-mentioned technical problems.

Best Mode for Carrying Out The Invention

The present invention is described in detail below.

The near-infrared ray absorption film of the present invention is a near-infrared ray absorption film obtained by containing a mixture of 2 or more kinds of diimmonium compounds having different numbers of substituents of n-propyl and isobutyl groups of the diimmonium compound represented by the formula (1) (hereinafter, also referred to as "the present diimmonium mixture") in a pressure-sensitive adhesive resin layer or an adhesive layer provided on a transparent support film, and has excellent properties as an optical filter and can absorb near-infrared rays in a wavelength region of 800 to 1100 nm.

The near-infrared ray absorption film having a layer containing the "present diimmonium mixture" is characterized by good near-infrared ray absorption and excellent "thermal stability", and when contained in the adhesive layer, it is superior in near-infrared ray absorption ability and low haze value to a diimmonium compound in which all substituents of the formula (1) are isobutyl groups (n ═ 0), and is superior in solvent solubility and easy to apply to a diimmonium compound in which all substituents of the formula (1) are n-propyl groups (n ═ 8). The "present diimmonium mixture" can be easily produced by a conventionally known method by adjusting the ratio of the amount of the alkylating agent to be added in the precursor production step as described below.

The "present diimmonium mixture" according to the present invention can be obtained, for example, by the method described in patent document 4. That is, the ammonia base represented by the following formula (2) obtained by the Ullmann reaction and the reduction reaction is mixed with the halogenated N-propyl compound and isobutyl compound at an arbitrary ratio in an organic solvent, preferably a water-soluble polar solvent such as Dimethylformamide (DMF), Dimethylimidazolidinone (DMI), N-methylpyrrolidone (NMP), at 30 to 160 ℃, preferably 50 to 140 ℃, and reacted to obtain a mixture of the compound represented by the formula (3). Alternatively, to control the ratio of n-propyl to isobutyl, mixtures of compounds in a certain ratio can be synthesized by reacting a compound corresponding to n-propyl (or isobutyl) and then a compound corresponding to isobutyl (or n-propyl).

(in the formula (3), n has the same meaning as in the formula (1).)

The mixture of the formula (3) synthesized as described above is subjected to oxidation reaction in an organic solvent, preferably a water-soluble polar solvent such as Dimethylformamide (DMF), Dimethylimidazolidinone (DMI), N-methylpyrrolidone (NMP), and the like, at 0 to 100 ℃, preferably 5 to 70 ℃, with 2 equivalents of tris (trifluoromethanesulfonyl) carbenium ion acid (Japanese text: トリス (トリフルオロメチルスルホニル) カルボニウム acid) added thereto, to obtain a "present diimmonium mixture" used in the present invention.

Next, a method of calculating the composition ratio of each diimmonium compound in the "present diimmonium mixture" will be described.

As a mass spectrometer for measuring the molecular ion peak intensity of each diimmonium compound [ 9 kinds of diimmonium compounds in which n in formula (1) is 0, 1, 2, 3, 4, 5, 6, 7, or 8 ], LCT manufactured by mackeloss corporation (japanese text: マイクロマス) was used. As a sample for measurement for calculating the composition ratio of each diimmonium compound, a compound of formula (3) (hereinafter referred to as a precursor) before cationization is used because it is difficult to directly measure the "present diimmonium mixture" after cationizationFurther, the reliability of the measured value is poor, and the correlation between the composition ratio of each precursor and the composition ratio of each component after cationization is extremely high. Specifically, electrospray ionization (ESI) ionization mass spectrum of a sample for measurement was measured to determine the molecular ion peak intensity [ M ] of each precursor⁺And calculating the composition ratio. The composition ratio A of each component is defined by A (%) (100 × [ M ]⁺(n is each precursor of 0 to 8 [ M ]⁺The sum of) is estimated. For example, the sum of the composition ratios of each component, n being 3 to 6, and B is B (%) (100 × (n is [ M ] of each precursor of 3 to 6)⁺The sum of (a)/(n is [ M ] of each precursor of 0 to 8⁺The sum of) is calculated.

The mixture in which the sum of the compositional proportions of the diimmonium compounds in which n is 3 to 6, calculated from the peak intensity of the mass spectrum as described above, is 70% to 98% of the total (n is the sum of the diimmonium compounds in which n is 0 to 8) is a more preferable mixture for the object of the present invention. The above composition can be easily prepared by adjusting the amount of the alkylating agent to be added, the reaction temperature and the reaction time.

The "present diimmonium mixture" used in the present invention may be used alone, but may be used in combination with 1 or more other near infrared ray absorbing compounds in order to adjust the absorption wavelength region and the absorption ratio of the desired near infrared ray, and specific examples of other near infrared ray absorbing compounds that can be used include diimmonium compounds other than the "present diimmonium mixture", nitroso compounds and metal salts thereof, cyanine compounds, squaraine (japanese unexamined patent publication: スクアリリウム) compounds, nickel mercaptide complex salt compounds, phthalocyanine compounds, naphthalocyanine compounds, triallylmethane compounds, naphthoquinone compounds, anthraquinone compounds, and the like. In the present invention, it is preferable to select and use a compound having an absorption maximum at a wavelength of 800 to 1100nm from among these compounds.

The method for producing a near-infrared absorbing film by forming a layer containing the present diimmonium mixture on a transparent support film will be described below. When the near-infrared absorbing compound is used in combination with a near-infrared absorbing compound other than the "present diimmonium mixture", it is advantageous to use a method of mixing and applying the near-infrared absorbing compound and the "present diimmonium mixture" in the same coating liquid, but the near-infrared absorbing compound and the "present diimmonium mixture" may be held as separate layers on the same transparent support film by a known method.

As a method of holding the "present diimmonium mixture" on the transparent support film, the following preferable methods can be mentioned: a method of forming an overcoat layer (hereinafter referred to as an adhesive resin layer) with an adhesive resin and containing the "present diimmonium compound" therein and a method of containing in the adhesive layer.

The transparent support film used in the present invention is not particularly limited in kind and thickness as long as it has high transparency, is not easily damaged, and is sufficient for use as an optical filter, but is preferable when the film has a thickness of 10 to 500 μm, and the kind of the film is preferably a film made of a polymer resin such as polyester, polycarbonate, triacetate, norbornene, acrylic, cellulose, polyolefin, or polyurethane, and polyethylene terephthalate (hereinafter referred to as PET) is preferable from the viewpoint of optical filter properties such as transparency, and easy availability. In order to absorb external ultraviolet rays and stabilize the functions of internal members, a transparent support film containing an ultraviolet absorbing substance may be used, and in order to improve the adhesion to the coating film, the surface of the film may be subjected to corona discharge treatment, plasma treatment, glow discharge treatment, roughening treatment, reagent treatment, anchor coating agent, primer coating agent, or the like to improve the adhesion.

The transparent support film may be a functional transparent support film having 1 or more functions such as antireflection, antiglare and antireflection, antistatic property, antifouling property, neon light absorption, electromagnetic wave shielding property, color toning property, and the like, and particularly when the adhesive layer of these functional transparent support films contains the "bisiminium mixture", a filter having both these functions and near infrared ray absorption can be obtained, and hence a reasonable filter having a good form can be obtained, and the use of a functional transparent support film is a good choice. As the functional transparent support film, a transparent support film having an antireflection function or an electromagnetic wave shielding function is preferable.

Next, examples of the above preferred functional transparent support film will be described, but the kind of the functional transparent support film is not limited to these.

A transparent support film (antireflection film) having an antireflection function is a film in which a low refractive index agent, a binder resin, and other additives are applied to the surface of a transparent support film such as PET to suppress reflection of light from the outside, or a film in which a hard coat layer and a high refractive index layer are provided between the transparent support film and the low refractive index layer to cancel out the reflected light of each layer and which has good visibility, and an antiglare and antireflection film is a film in which fine particles are contained in the high refractive index layer or the hard coat layer of the antireflection film to diffusely reflect light from the outside and which has good visibility. The above-mentioned film is readily available on the market, and examples thereof include ア - クトップ series (manufactured by Asahi glass, Ltd.), カヤコ - ト ARS series (manufactured by Nippon Kayaku Co., Ltd.), カヤコ - ト AGRS series (manufactured by Nippon Kayaku Co., Ltd.), and リアルック series (manufactured by Nippon fat and oil Co., Ltd.).

The method for shielding electromagnetic waves of the transparent support film (electromagnetic wave shielding film) having an electromagnetic wave shielding function includes: when a thin film type is used for a PDP (normally, near infrared rays are reflected but not transmitted), a near infrared ray absorption film is not required. Therefore, in the present invention, when the electromagnetic wave-shielding film is used, it is preferable to use a mesh-type electromagnetic wave-shielding film as the transparent support film. A film having antireflection properties and electromagnetic wave shielding properties, which is obtained by providing a conductive ink with a mesh-like electromagnetic wave shielding layer by screen printing or the like on the reverse surface of the antireflection film, is used as a transparent support film, and is suitable for producing an optical filter for a PDP.

The transparent support film having other functions usable in the present invention includes transparent support films having 1 or more kinds of functions such as neon light absorption, ultraviolet light absorption, antistatic property, antifouling property, toning property, and the like, and they can be produced by a known method such as a method of molding from a binder resin composition containing each compound having the above-mentioned properties.

First, a method of containing the "present diimmonium mixture" in the adhesive layer will be described. The resin used as the main component of the adhesive layer is not particularly limited as long as it can uniformly disperse the "present diimmonium mixture" and form a transparent layer on the surface of the transparent support film without impairing the function as an optical filter, and examples thereof include adhesive materials such as acrylic, polyester, polyamide, polyurethane, polyolefin, polycarbonate, rubber, and polysiloxane resins, and acrylic resin adhesive materials are preferable from the viewpoint of excellent transparency, adhesiveness, heat resistance, and the like. The acrylic resin adhesive material is obtained by copolymerizing an acrylic alkyl ester having no functional group (excluding double bonds) as a main component with an acrylic alkyl ester having a functional group or other monomer components other than the acrylic alkyl ester. The copolymerization ratio of the acrylic alkyl ester having a functional group or other monomer components other than the acrylic alkyl ester is 0.1 to 20 parts by weight, more preferably 1 to 10 parts by weight, based on 100 parts by weight of the acrylic alkyl ester component having no functional group.

Examples of the acrylic alkyl ester having no functional group include alkyl acrylates and alkyl methacrylates having 1 to 12 carbon atoms of the alkyl group such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, or dodecyl (meth) acrylate, and 2 or more of these may be used in combination as necessary.

The monomer other than the acrylic alkyl ester having a functional group or the acrylic alkyl ester is used as a monomer which acts as a crosslinking point of a crosslinking agent described later, and the kind thereof is not particularly limited, and examples thereof include a hydroxyl group-containing (meth) acrylate monomer such as 2-hydroxyethyl (meth) acrylate or hydroxypropyl (meth) acrylate, an amino group-containing (meth) acrylic monomer such as N, N-dimethylaminoethyl acrylate or N-tert-butylaminoethyl acrylate, and acrylic acid or maleic acid, and 2 or more kinds thereof may be used in combination as necessary.

The binder is preferably used in a composition in which the acrylic resin and the like can be crosslinked by adding a crosslinking agent. The crosslinking agent is suitably used depending on the kind of the monomer, and examples thereof include aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylolpropane adduct of hexamethylene diisocyanate, polyisocyanate compounds such as aromatic diisocyanates such as tolylene diisocyanate and trimethylolpropane adduct of tolylene diisocyanate, melamine compounds such as butylated styrene melamine and trimethylolmelamine, diamine compounds such as hexamethylenediamine and triethylenediamine, epoxy resin compounds such as bisphenol A and epichlorohydrin, urea resin compounds, and metal salts such as aluminum chloride, iron chloride and aluminum sulfate, and the amount thereof is usually 0.005 to 5 parts by weight, preferably 0.01 to 3 parts by weight, per 100 parts by weight of the acrylic resin binder.

The acrylic resin-based pressure-sensitive adhesive is preferable because it is excellent in adhesive strength and cohesive strength, has high stability against light and oxygen because of no unsaturated bond in the crosslinked polymer, and has a high degree of freedom in selection of the kind and molecular weight of the monomer. In order to maintain adhesion to the transparent support film, the molecular weight (polymerization degree) is preferably high, that is, the weight average molecular weight (Mw) of the main polymer is preferably about 60 to 200 ten thousand, and more preferably about 80 to 180 ten thousand.

In the PDP, orange neon light having a wavelength of 550 to 620nm, such as neon gas generated when a voltage is applied, causes a reduction in the color purity of red light, and therefore, a neon light absorbing filter in which a neon light absorbing compound is held in a transparent support film is generally used because the red light needs to be shielded to some extent in front of a display. Examples of the neon light-absorbing compound that can be used here include compounds such as azaporphyrins, cyanines, squarylium cyanines, methylidene amines, xanthenes, oxonoles, and azo compounds, and particularly when contained in the adhesive layer, it is necessary to sufficiently consider the "thermal stability" of the "present diimmonium mixture" used. For example, porphyrazine compounds are relatively stable, and other compounds can be used if they can be stabilized.

The "present diimmonium mixture" is sufficiently dissolved or dispersed in a solvent such as Methyl Ethyl Ketone (MEK) together with the above-mentioned binder, polymerization initiator, crosslinking agent, ultraviolet absorber, tinting color and other necessary additives, such as an antioxidant and rust inhibitor used when discoloration occurs upon contact with a metal used in a mesh for electromagnetic wave shielding, as a main component of the binder, to form a binder liquid, and the binder liquid is applied onto the surface of the transparent support film so that the dried layer has a thickness of 5 to 100 μm, preferably 10 to 50 μm. The coating method is not particularly limited, and the following methods may be exemplified: a method of coating with a bar coater, a reverse coater, a comma coater, a gravure coater, or the like, drying the coating, and bonding the adhesive layers; a method in which an adhesive liquid is applied to a release film by a bar coater, a reverse coater, a comma coater, a gravure coater, or the like, and after drying, the adhesive layer is transferred to a transparent support film, and the like. The amount of the solvent used varies depending on the coating method, and when an acrylic resin-based adhesive having a weight average molecular weight of the main polymer of about 100 ten thousand is used and coated by a comma coater, the adhesive is preferably diluted to 10 to 25% by weight with the solvent. The near infrared ray absorption film of the present invention is preferably designed so that the transmittance of near infrared rays having a wavelength of 800 to 1100nm is 10% or less, and the amount of the "present diimmonium mixture" is preferably used in accordance with the transmittance, and the content of the adhesive layer is about 1 to 20% by weight.

The "present diimmonium mixture" is a mixture of 2 or more kinds of diimmonium compounds, and if only a single diimmonium compound having 8 n-propyl groups (n ═ 8 in formula (1)), the solubility in a solvent such as MEK, which is often used as a solvent in coating, is insufficient, aggregates are likely to be generated on the coated surface, and the near infrared ray absorption tends to deteriorate. A mixture having a high n-propyl group, i.e., a high ratio of the diimmonium compound is difficult to coat because of poor solvent solubility. In addition, when all of 8 groups are isobutyl groups (n is 0 in formula (1)), the near infrared ray absorption ability is slightly inferior to that of the "present diimmonium mixture", and the haze value is also high, and in the "present diimmonium mixture", the higher the content of the diimmonium compound in which n is small, i.e., isobutylidene group, is, the higher the haze value is. As described above, the "present diimmonium mixture" is superior to a mixture using 8 n-propyl groups and 8 isobutyl groups in physical properties and ease of handling, and the "present diimmonium mixture" is more preferably a mixture of compounds that do not excessively deviate from either group, and is more preferably a mixture in which the sum of the composition ratios of diimmonium compounds having n of 3 to 6 calculated from the peak intensity of the mass spectrum is 70% to 98% of the total (the sum of the composition ratios having n of 0 to 8).

Next, a method of holding the present diimmonium mixture as a binder resin layer on the transparent support film will be described.

The following methods can be employed: the "present diimmonium mixture" is dissolved and/or dispersed in a solvent together with a binder resin and, if necessary, a neon light absorbing coloring matter, a color adjusting coloring matter, a leveling agent, an antistatic agent, an antioxidant, a dispersant, a flame retardant, a lubricant, a plasticizer, an ultraviolet absorber, and other additives to form a coating liquid, and the coating liquid is applied and dried by a coater. When a binder resin such as thermosetting or active energy ray-curable is used, a curing step is required after drying, and since the curing heat or active energy ray deteriorates or increases the number of steps of a near infrared ray and neon light absorbing compound, it is preferable to use a thermoplastic binder resin unless otherwise specified.

The binder resin is not particularly limited as long as it is easily applied, has good adhesion to the transparent support film, has good visible light transmittance, and has no problem in surface quality and the like, and is preferably selected from thermoplastic resins such as polyester resins, acrylic resins, polyamide resins, polyurethane resins, polyolefin resins, and polycarbonate resins from the viewpoint of easy handling. After the coating and winding into a roll, it is preferable to select a material having a glass transition temperature and other physical properties which do not cause problems such as blocking (Japanese text: ブロッキング) during storage and which does not adversely affect the "thermal stability" of the "present diimmonium mixture" used.

Examples of the solvent include alcohols such as methanol, ethanol, isopropanol, diacetone alcohol, ethyl cellosolve, and methyl cellosolve; ketones such as acetone, Methyl Ethyl Ketone (MEK), cyclopentanone, and cyclohexanone; amides such as N, N-dimethylformamide and N, N-dimethylacetamide; sulfoxides such as dimethyl sulfoxide; ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether; esters such as methyl acetate, ethyl acetate, or butyl acetate; aliphatic hydrocarbons such as chloroform, dichloromethane, dichloroethylene and trichloroethylene; aromatic compounds such as benzene, toluene, xylene, monochlorobenzene, dichlorobenzene, or the like; or aliphatic hydrocarbons such as n-hexane and n-heptane; fluorine-based solvents such as tetrafluoropropanol and pentafluoropropanol are preferred, and solvents having high solubility in each material, no adverse effect on coating and drying, and no problem in safety are preferably selected.

Of the additives used as needed, the same neon light absorbing compound as used in the case of the above-mentioned adhesive layer is used, and other additives are used in the form of a solution in consideration of the "thermal stability" of the "present diimmonium mixture" used and the required quality performance.

The coating liquid is applied by a known coating method such as a flow coating method, a spray coating method, a bar coating method, a gravure coating method, a roll coating method, a blade coating method, an air knife coating method, a blade coating method, or a die coating method, and the layer thickness at the time of coating is usually 0.1 to 30 μm, preferably 0.5 to 10 μm, and the treatment layer is fixed by drying. When additional curing is required, the treatment layer is fixed by curing after drying. As for the shielding property of near infrared ray, it is preferable to design the transmittance of near infrared ray with wavelength of 800 to 1100nm to be 10% or less, as in the case of containing the "present diimmonium compound" in the adhesive layer. The amount of the solvent used varies depending on the coating method, and when a thermoplastic acrylic resin-based adhesive having a weight average molecular weight of the main polymer of about 30 ten thousand is used and coating is performed by a mini gravure coater, it is preferably diluted to 15 to 30% by weight with the solvent.

When the adhesive resin layer contains a diimmonium compound, the most commonly used diimmonium compound having hexafluoroantimonate ion as an anion, for example, カヤソルブ IRG-022 (trade name, manufactured by japan chemical company), and most of diimmonium compounds are poor in "thermal stability" when a binder resin having a low Tg of 85 ℃ or lower is used as described in patent document 3, but the "present diimmonium compound" can use a binder resin having a temperature of 85 ℃ or lower, and it is sufficient to dry under ordinary drying conditions without managing the amount of residual solvent in the adhesive resin layer as disclosed in patent document 3. In addition, the "present diimmonium mixture" is easy to handle because it has excellent solvent solubility compared to a single product in which all substituents in the formula (1) are n-propyl (n-8), "the present diimmonium mixture" can provide an excellent near infrared ray absorption film even by a method of containing the mixture in a binder resin layer.

Next, the near-infrared ray absorption film of the present invention having a layer containing the present diimmonium mixture provided on the transparent support film is laminated or bonded as the lowest component with a transparent support film having the following functions to obtain the optical filter of the present invention. These filters are preferably used for a PDP, and the filter of the present invention may be attached to a transparent glass plate or plastic plate and then attached to the front surface of the PDP, or may be directly attached to the front surface of the PDP.

Examples of the structures of the various thin films in the optical filter of the present invention include the following (1) to (13).

In the following description, NIRA indicates near infrared absorptivity, NeA indicates neon light absorptivity, a portion in the middle parentheses ({ }) indicates a near infrared ray absorption film of the present invention, and a portion in the small parentheses (()) indicates a functional film other than the present invention. As is clear from these configuration examples, when the "present diimmonium compound" or the neon light absorbing compound is contained in the adhesive layer of the functional transparent support film such as the antireflection transparent support film, the filter for PDP can be manufactured by simply bonding 2 kinds of films. An electromagnetic wave shielding film having a mesh on the back surface of the antireflection film was used as a transparent support film, and a pressure-sensitive adhesive resin layer or an adhesive layer containing a "present diimmonium compound" and a neon light absorber was provided on the mesh surface, so that a filter for PDP was produced from 1 type of film. The optical filter of the present invention is preferably in the form of containing the near infrared ray absorption film of the present invention and a film having an electromagnetic wave shielding ability or a film having an antireflection function.

(1) { antireflection film/NIRA. NeA. toning adhesive layer }/{ electromagnetic wave-shielding film/adhesive layer }),

(2) { antireflection film/NIRA toning adhesive layer }/(electromagnetic wave shielding film/NeA adhesive layer),

(3) (antireflection film/adhesive layer)/{ electromagnetic wave-shielding film/NIRA NeA toning adhesive layer }),

(4) { anti-glare/anti-reflection film/NIRA NeA toning adhesive layer }/(electromagnetic wave shielding film/adhesive layer),

(5) (antireflection film/adhesive layer)/{ NIRA. NeA adhesive resin layer/PET/toner adhesive layer }/(electromagnetic wave-shielding film/adhesive layer),

(6) (antireflection film/adhesive layer)/{ NeA film/NIRA toning adhesive layer }/(electromagnetic wave shielding film/adhesive layer),

(7) (antireflection film/adhesive layer)/(electromagnetic wave-shielding film/adhesive layer)/{ NeA film/NIRA. toning adhesive layer }),

(8) (antireflection film/adhesive layer)/(electromagnetic wave-shielding film)/{ NIRA. NeA absorption adhesive layer/PET/toning adhesive layer }),

(9) (antireflection film/adhesive layer)/{ NIRA. NeA adhesive resin layer/PET/toner adhesive layer }/(electromagnetic wave-shielding film/adhesive layer),

(10) { antireflection film/NIRA. NeA adhesive resin layer/toning adhesive layer }/(electromagnetic wave shielding film/adhesive layer)

(11) { antireflection film/NIRA. NeA adhesive resin layer/toning adhesive layer }/(electromagnetic wave shielding film/adhesive layer)

(12) { antireflection film/electromagnetic wave-shielding layer/NIRA adhesive resin layer/NeA adhesive layer }

(13) { antireflection film/electromagnetic wave-shielding layer/NIRA. NeA adhesive layer }

Examples

The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to these examples. In the examples, parts represent parts by weight, and% represents% by weight.

Synthesis example 1

(substitution reaction)

To 100 parts of DMF were added 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 and 3 parts of 1-bromopropane, and the mixture was reacted at 90 ℃ for 2 hours and then at 110 ℃ for 6 hours. The crystals precipitated after cooling were filtered, and the obtained crystals were dissolved in hot DMF. After removing insoluble components, methanol was added to the solution, and the precipitated crystals were filtered, washed with water, and dried to obtain 6.8 parts of a pale green crystal precursor (see the above formula (3)).

(Oxidation reaction)

5 parts of the precursor crystal was added to 40 parts of DMF, and after dissolving the precursor crystal by heating to 60 ℃, 9 parts of a 58% aqueous solution of tris (trifluoromethanesulfonyl) carbonium ion acid was added, and then 1.9 parts of silver nitrate dissolved in 30 parts of DMF was added, followed by stirring under heating for 30 minutes. After insoluble matter was filtered, 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 diimmonium compounds. The composition ratios of the respective components in the mixture were calculated by the above-mentioned methods, and the results are shown in Table 1. The maximum absorption wavelength of this mixture was 1107nm (dichloromethane).

Synthesis example 2

(substitution reaction)

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 changed to 7.3 parts, to obtain 6.5 parts of a greenish crystal precursor.

(Oxidation reaction)

The oxidation reaction and purification were carried out in the same manner as in Synthesis example 1 except that the precursor obtained in Synthesis example 1 was changed to the above precursor, to obtain 4.5 parts of a mixture of diimmonium compounds. The composition ratios of the respective components in the mixture were calculated by the above-mentioned methods, and the results are shown in table 1. The maximum absorption wavelength of this mixture was 1092nm (dichloromethane).

Synthesis example 3

(substitution reaction)

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 changed to 10 parts, to obtain 6.2 parts of a greenish crystal precursor.

(Oxidation reaction)

The oxidation reaction and purification were carried out in the same manner as in Synthesis example 1 except that the precursor of Synthesis example 1 was changed to the above precursor, to obtain 6.1 parts of a mixture of diimmonium compounds. The composition ratios of the respective components in the mixture were calculated by the above-mentioned methods, and the results are shown in table 1. The maximum absorption wavelength of this mixture was 1103nm (dichloromethane).

Synthesis example 4

(substitution reaction)

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 changed to 12.7 parts, to obtain 7.6 parts of a greenish crystal precursor.

(Oxidation reaction)

The oxidation reaction and purification were carried out in the same manner as in Synthesis example 1 except that the precursor of Synthesis example 1 was changed to the above precursor, to obtain 5.4 parts of a mixture of diimmonium compounds. The composition ratios of the respective components in the mixture were calculated by the above-mentioned methods, and the results are shown in table 1. The maximum absorption wavelength of this mixture was 1101nm (methylene chloride).

Table 1 shows the proportions of the respective components in the mixtures of diimmonium compounds obtained in Synthesis examples 1 to 4.

(solubility in solvent)

The solvent solubility of the diimmonium compounds obtained in Synthesis examples 1 to 4 and the diimmonium compounds used in comparative examples 1, 2 and 3 was measured by the following method.

A5% methyl ethyl ketone solution of the object diimmonium compound was prepared at room temperature, and the dissolved state was observed. As a result, it was found that the diimmonium compound used in Synthesis examples 1 to 4 and comparative examples 2 and 3 was transparent, but the diimmonium compound used in comparative example 1 was not dissolved at all and had a precipitate.

[ Table 1 ]

(Table 1) composition Table

Example 1

(preparation of near Infrared ray absorption film 1)

A coating solution obtained by uniformly mixing and dissolving the respective raw materials shown in Table 2 below was applied to MRF-75 (trade name, PET release film, manufactured by Mitsubishi chemical polyester film) by a comma coater at a coating speed of 0.8 m/min and a drying temperature of 110 ℃ to form an adhesive layer having an adhesive layer thickness of 18 μm. Then, the above PET release film provided with the adhesive layer was pressed and laminated by a roll on the reverse side of the antireflection surface of KAYACOAT ARS-D501 (trade name, antireflection film, manufactured by japan chemical products) to obtain the near infrared ray absorption film 1 of the present invention having antireflection property and absorbing neon light.

[ Table 2 ]

(Table 2)

Amount of material used

Synthesis example 1 mixture of diimmonium Compound 1.00 parts

TAP-2 (product name: Neon light absorber manufactured by Shantian chemical industry Co., Ltd.) 0.09 part

チヌビン (trade name: UV absorbent Qiba Gai (チバガイギ one))

103.00 parts of PTR-104 (trade name: acrylic resin Japan chemical)

コロネ - ト HL (trade name: made of Japan polyurethane curing agent) 0.023 parts

MEK 64.00 parts

(Note) TAP-2: porphyrazine compounds, チヌビン 109: benzotriazole compound, コロネ - ト HL: isocyanate curing agent

Example 2

(preparation of near Infrared ray absorption film 2)

A near-infrared ray absorption film 2 of the present invention having antireflection properties and absorbing neon light was obtained in the same manner as in example 1 except that the diimmonium compound mixture of synthesis example 1 was replaced with the diimmonium compound mixture of synthesis example 2.

(production of Filter 1 for PDP)

The protective film of ES-1534U (HCD-42-02) A (trade name, electromagnetic wave shielding film, Hitachi chemical industry) was peeled off, and the near infrared ray absorbing film 2 was adhered to the film via an adhesive layer, thereby obtaining a filter for PDP of the present invention. The filter may be directly attached to the front surface of the PDP module, or may be attached to a glass plate (transparent plate) and then attached to the front surface of the module, thereby fully exhibiting the necessary performance as a filter for a PDP.

Example 3

(preparation of near Infrared ray absorption film 3)

A near-infrared ray absorption film 3 of the present invention having antireflection properties and absorbing neon light was obtained in the same manner as in example 1 except that the diimmonium compound mixture of synthesis example 3 was used instead of the diimmonium compound mixture of synthesis example 1 of example 1.

(production of Filter 2 for PDP)

The protective film of ES-1534U (HCD-42-02) A (trade name, electromagnetic wave shielding film, Hitachi chemical industry) was peeled off, and the near infrared ray absorbing film 3 was adhered to the film via an adhesive layer to obtain a filter for PDP of the present invention. The filter can be directly attached to the front surface of a PDP module through an adhesive layer of an electromagnetic wave shielding film, or can be attached to a glass plate and then attached to the front surface of the module, thereby fully exhibiting the necessary performance as a filter for a PDP.

Example 4

(preparation of near Infrared ray absorption film 4)

A near-infrared ray absorption film 4 of the present invention having antireflection properties and absorbing neon light was obtained in the same manner as in example 1 except that the diimmonium compound mixture of synthesis example 1 was replaced with the diimmonium compound mixture of synthesis example 4.

Example 5

(preparation of near Infrared ray absorption film 5)

A coating solution was prepared by dissolving 0.5 part of the diimmonium compound mixture of Synthesis example 2 and 37 parts of フォレット PAN-125 (trade name, acrylic binder resin having a Tg of 70 ℃ C., manufactured by Kagaku Co., Ltd.) in 40 parts of MEK. The coating liquid was applied to コスモシャイン a4300 (trade name, polyester film 100 μm thick, manufactured by toyobo textile) by a micro gravure roll for a micro gravure coater at a line speed of 10 m/min, and dried at 70 to 130 ℃.

Comparative example 1

A near-infrared ray absorption film for comparison was obtained in the same manner as in example 1, except that 44.7 parts of 1-bromopropane was used in place of 32 parts of isobutyl bromide and 12.7 parts of 1-bromopropane in synthesis example 1, and a diimmonium compound in which 8 substituents in formula (1) are all n-propyl groups was prepared in the same manner as in synthesis example 1, and a mixture of the diimmonium compound in synthesis example 1 was used in place of the diimmonium compound in synthesis example 1.

Comparative example 2

A near-infrared absorbing film for comparison was obtained in the same manner as in example 1, except that a diimmonium compound in which 8 substituents in formula (1) are all isobutyl groups was prepared in the same manner as in synthesis example 1, except that 44.7 parts of isobutyl bromide was used instead of 32 parts of isobutyl bromide and 12.7 parts of 1-bromopropane in synthesis example 1, and a mixture of diimmonium compounds in synthesis example 1 was replaced with the diimmonium compound.

Comparative example 3

A near-infrared ray absorption film for comparison containing a near-infrared ray absorbent in a binder resin layer was obtained in the same manner as in example 5, except that カヤソルブ IRG-022 (trade name: a diimmonium compound of antimony hexafluoride anion, manufactured by Nippon chemical Co., Ltd.) was used in place of the diimmonium compound mixture of Synthesis example 2 in example 5 in the same amount.

Performance test (1) (near Infrared ray absorption film having near Infrared ray absorber in adhesive layer)

The near-infrared absorbing films obtained in examples 1 to 4 and the near-infrared absorbing films for comparison obtained in comparative examples 1 and 2 were stored in a constant temperature bath at 80 ℃, and the transmittance, transmittance (Y%) and change in chromaticity coordinates (x, Y) at each maximum absorption wavelength at 500 hours of storage were measured to compare the heat resistance of each test piece. The transmittance was measured by UV-3150 (trade name, spectrophotometer, shimadzu corporation), and the transmittance and chromaticity coordinates (x, y) were calculated from the transmittance according to the color expression method of XYZ color system of JIS Z8701. The haze value was measured according to TC-H3DPK (trade name, haze Meter, manufactured by Tokyo electro-chromic technology center). Further, the change in appearance was observed with the naked eye.

The results of the performance test (1) are shown in Table 3.

[ Table 3]

(Table 3) results of Performance test (1) < Heat resistance >

(analysis) comparative example 1 using the diimmonium compound represented by the above formula (1) wherein n is 8 had a high haze value, and aggregates were generated. The haze value and the near infrared ray absorptance of comparative example 2 using the diimmonium compound (1) in which n is 0 are poor. In contrast, the near-infrared ray absorption films of examples 1 to 4 using the mixture of 2 or more kinds of diimmonium compounds having different n according to the present invention have practical results in any item, and particularly, the near-infrared ray absorption films of examples 2 to 4 containing the mixture of diimmonium compounds in which the sum of the components of formula (1) in which n is 3 to 6 is 70% or more in the adhesive layer are superior to the film of 70% or less in both the haze value and the near-infrared ray shielding rate (example 1). The results of the test for wet heat resistance (60 ℃, RH 90%, 500 hours) were also substantially the same as the above results. The results of the moist heat resistance are shown in Table 4.

[ Table 4]

(Table 4) results of Performance test (1) < moist Heat resistance >

Performance test (2) (near Infrared ray absorption film containing near Infrared ray absorber in adhesive resin layer)

The near-infrared ray absorption film obtained in example 5 (the present invention) and the near-infrared ray absorption film for comparison obtained in comparative example 3 were subjected to the same performance test (heat resistance) as in the performance test (1), and the results shown in table 5 were obtained.

[ Table 5]

(Table 5) Performance test (2) < Heat resistance >

(analysis) in the heat resistance test, the transmittance of the near infrared ray was 10% or less, and the transmittance of comparative example 3 was greatly changed. In the chromaticity coordinates, although the Tg of the binder resin was low at 70 ℃ in example 5, the change was small and the appearance was not changed, whereas in comparative example 3, the change in the chromaticity coordinates y was large and the appearance was changed with a yellowish tint due to the influence of Tg. The results of the test for wet heat resistance (60 ℃, RH 90%, 500 hours) were also substantially the same as the above results. The results of the moist heat resistance are shown in Table 6.

[ Table 6]

(Table 6) Performance test (2) < Wet Heat resistance >

Claims (12)

1. A near-infrared ray absorption film characterized in that a layer formed on a transparent support film contains a mixture of 2 or more kinds of diimmonium compounds having different n, which are represented by the following formula (1),

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

2. The near-infrared ray absorption film according to claim 1, wherein the mixture of 2 or more diimmonium compounds of formula (1) having different n contains 70% to 98% of the diimmonium compound of formula (1) wherein n is 3 to 6 in a composition ratio calculated from the peak intensity of the mass spectrum.

3. The near infrared ray absorption film according to claim 1 or claim 2, wherein the layer formed on the transparent support film is an adhesive layer.

4. The near-infrared ray absorption film according to claim 1 or 2, wherein a layer formed on the transparent support film contains a mixture of 2 or more diimmonium compounds having different n of the formula (1) and a compound having an absorption maximum at a wavelength of 550 to 620 nm.

5. The near-infrared ray absorption film according to claim 3, wherein the layer formed on the transparent support film contains a mixture of 2 or more kinds of diimmonium compounds having different n of the formula (1) and a compound having an absorption maximum at a wavelength of 550 to 620 nm.

6. The near infrared ray absorption film according to claim 1 or 2, wherein the transparent support film is a film having an antireflection function or an electromagnetic wave shielding function.

7. The near infrared ray absorption film according to claim 3, wherein the transparent support film is a film having an antireflection function or an electromagnetic wave shielding function.

8. The near infrared ray absorption film according to claim 4, wherein the transparent support film is a film having an antireflection function or an electromagnetic wave shielding function.

9. The near infrared ray absorption film according to claim 5, wherein the transparent support film is a film having an antireflection function or an electromagnetic wave shielding function.

10. An optical filter for a plasma display panel, comprising the near-infrared ray absorption film according to any one of claims 1 to 9.

11. The filter for a plasma display panel according to claim 10, comprising the near infrared ray absorption film according to any one of claims 1 to 9 and a film having an electromagnetic wave shielding ability and/or a film having an antireflection function.

12. A mixture of 2 or more diimmonium compounds represented by the formula (1) wherein n is different,

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