JP4942320B2 - Near-infrared absorbing adhesive film and optical filter using the same - Google Patents

Description

  The present invention relates to a filter used as an optical application. More specifically, the present invention relates to a near-infrared absorbing adhesive film having near-infrared absorbing ability and an optical filter for a plasma display panel (hereinafter referred to as PDP) using the same.

  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 a filter having a function of shielding near-infrared rays on the front of the kind.

  The principle of PDP is that a voltage is applied to a rare gas (neon, xenon, etc.) enclosed in a cell sandwiched between two plate-like glasses, and the ultraviolet light generated at that time is applied to a light emitter treated on the cell wall surface. It generates visible light that is necessary for UV light, but it is also harmful to visible light, near infrared rays, electromagnetic waves that are harmful to the human body, neon gas, and orange light that lowers the purity of red light (hereinafter referred to as neon light). In the PDP, visible light that is useful is transmitted, but harmful electromagnetic waves such as near infrared rays need to be shielded, and an optical filter for this purpose is required.

  Near-infrared absorption filters used for optical filters are used to shield near-infrared rays. For this, a compound that absorbs near-infrared rays is used for the surface of a transparent support or a film that shields electromagnetic waves harmful to the human body (hereinafter, There is a method of coating the surface of a transparent functional film such as an electromagnetic wave shielding film) with a polymer resin as a binder. There are several types of near-infrared absorbing compounds used here, but usually, based on a diimonium salt compound having a wide absorption wavelength range to cover the wavelength range where near-infrared absorption is required. , Alone or in combination with several other compounds. However, as the diimonium salt compound, the diimonium salt compound of hexafluoroantimonate ion is mainly used, but this compound is classified as a deleterious substance, and regulations on heavy metals etc. originating from environmental problems are severe. For this reason, there has been a demand for a diimonium salt compound that is safer and has a wider near-infrared absorption wavelength range. 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, but a diimonium salt compound is disclosed. In general, the properties of insufficient heat stability and moist heat resistance have not been improved even in these compounds.

  As a stabilization technique of the diimonium salt compound, Patent Document 3 discloses that the stabilization can be achieved by containing the diimonium salt compound in a state where the amount of the solvent remaining in the polymer resin film layer is controlled to a certain ratio or less. Therefore, it is necessary to control the amount of the residual solvent, and a more general coating method and a method for obtaining a polymer resin film layer containing a diimonium salt compound having good heat resistance and heat-and-moisture resistance by a drying method have been desired. Patent Document 5 discloses an optical filter having a near-infrared absorbing ability in which a diimonium salt compound of tris (fluoromethanesulfonyl) imide anion and tris (fluoromethanesulfonyl) carboanion is contained in a coating layer of a transparent polymer resin. It is disclosed that the diimonium salt compound of the tris (fluoromethanesulfonyl) imide anion has good heat resistance and moisture resistance according to specific compound examples. However, with respect to the diimonium salt compound of tris (fluoroalkylsulfonyl) carbanion, there is no description of the specific compound name, production method, physical properties, or usage example.

  Moreover, as a method for retaining the near infrared ray absorbing compound, there is a method of containing it in a transparent adhesive layer in addition to the polymer resin film layer, and in this method, an adhesive layer such as a reduced reflection film or electromagnetic wave shielding film constituting an optical filter. Compared to the method of separately providing a layer containing a near-infrared absorbing compound, the coating process can be omitted, so the cost merit is great, but it is much more heat-resistant than when it is contained in the polymer resin film layer. It has been considered that the technical hurdle is high because the heat resistance and heat-and-moisture resistance are poor (the adhesive layer in the present invention means a transparent adhesive layer). Patent Document 4 discloses a technique of containing an ultraviolet absorber and a hindered amine light stabilizer so that the near-infrared absorbing compound contained in the adhesive layer is not deteriorated by ultraviolet rays. There is no description, and 10 types of dyes are listed as near-infrared absorbing compounds, but there is no description of diimonium salt compounds. Patent Document 5 mentions not only the diimonium salt compound of tris (fluoromethanesulfonyl) carboanion, but also the method of stabilizing the diimonium salt compound of tris (fluoromethanesulfonyl) imide anion by containing it in the adhesive layer. No description is given, and the adhesive layer contains a diimonium salt compound having near-infrared absorptivity and is particularly excellent in heat resistance and moist heat resistance, and is applied as an adhesive layer to various functional transparent bodies required for optical films. It has been desired to develop a technology for obtaining a versatile near-infrared absorbing adhesive layer that can be used, and an optical filter for PDP that uses the same and has high production efficiency.

  Patent Document 8 describes an infrared-absorbing pressure-sensitive adhesive composition for electronic displays and an infrared-absorbing sheet having a long-term stable infrared-absorbing property. It is a type that cures with energy rays, and may cause alteration of the infrared absorbing compound in the adhesive layer.

JP 10-316633 A (page 5) Japanese Patent Publication No. 7-51555 (2nd page) JP 2000-227515 A JP 2004-182936 A (page 3-11) Japanese Patent Laying-Open No. 2005-49848 (page 2-12) Japanese Patent Publication No. 43-25335 (pages 7-14) JP 2004-309655 A Japanese Patent No. 3621322

  A diimonium salt compound with a relatively wide absorption wavelength range of near infrared, and even if it is included in the adhesive layer, a compound that can maintain excellent heat resistance and moist heat resistance is found, and this is included in the adhesive layer to prevent near infrared shielding. Development of a near-infrared absorbing adhesive film for general use as an optical filter by pressure bonding to a required transparent member, and further PDP integrated with other functional transparent bodies required by PDP It is an object of the present invention to develop an optical filter for use.

  As a result of intensive studies, the inventors of the present invention have included a near-infrared absorbing adhesive film in which a diimonium salt compound having a specific anion is contained in an adhesive layer and sandwiched by a release film, and an optical filter for PDP using the same. It has been found that the above-mentioned problems can be solved, and the present invention has been completed. The pressure-sensitive adhesive layer of the near-infrared absorbing pressure-sensitive adhesive film of the present invention is also called a pressure-sensitive adhesive layer, and is applied to an object (hereinafter referred to as a functional transparent body) such as a transparent functional film or a module protective substrate. It means a layer having pressure-sensitive adhesiveness for pressing (applying pressure) to the adherend surface from above (hereinafter referred to as pressure bonding).

That is, the present invention provides (1) a near-infrared absorbing adhesive film, wherein an adhesive layer containing a diimonium salt compound represented by formula (1) is sandwiched between release films,

(In Formula (1), R _{1 to} R ₈ each independently represents an aliphatic hydrocarbon group which may have a hydrogen atom or a substituent, and R _{9 to} R ₁₁ each independently have a halogen atom. Each represents an optionally substituted aliphatic hydrocarbon group).
(2) The near-infrared absorbing adhesive film according to (1), wherein at least one of R _{1 to} R _{8 in} the formula (1) is a branched alkyl group,
(3) The near-infrared absorbing adhesive film according to (2), wherein all of R _{1 to} R ₈ in formula (1) are branched alkyl groups,
(4) The near-infrared absorbing adhesive film according to (3), wherein all of R _{1 to} R ₈ in formula (1) are iso-butyl groups,
(5) The near-infrared absorbing pressure-sensitive adhesive film according to (3), wherein all of the branched alkyl groups are alkyl groups having 3 to 5 carbon atoms branched at the ends,
(6) The near-infrared absorbing adhesive film according to any one of (1) to (5), wherein all of R _{9 to} R ₁₁ in formula (1) are aliphatic hydrocarbon groups having a fluorine-containing atom,
(7) The near-infrared absorbing adhesive film according to (6), wherein all of the aliphatic hydrocarbon groups having a fluorine-containing atom are trifluoromethyl groups,
(8) The near-infrared absorbing adhesive film according to any one of (1) to (7), wherein an antioxidant is contained in the adhesive layer,
(9) The near-infrared absorbing adhesive film according to any one of (1) to (8), wherein the amount of the organic acid contained in the adhesive layer is 0.5% by weight or less,
(10) The compound according to any one of (1) to (9), wherein a compound having a maximum absorption at a wavelength of 550 to 620 nm is contained in the adhesive layer together with the diimonium salt compound of the formula (1). Near-infrared absorbing adhesive film,
(11) The near-infrared absorptivity according to any one of (1) to (10), wherein the release films sandwiching the pressure-sensitive adhesive layer have different release forces on both sides of the pressure-sensitive adhesive layer. Adhesive film,
(12) An optical filter for a plasma display panel, comprising the near-infrared absorbing adhesive layer according to any one of (1) to (10),
About.

  The diimonium salt compound of the above formula (1) having near infrared absorption ability used in the present invention does not correspond to a deleterious substance because it does not contain heavy metals such as antimony, and the near infrared absorption layer using this is in the range of 700 to 1100 nm. Absorbs near-infrared light in the wavelength range well, exhibits excellent heat resistance and heat-and-moisture resistance, has excellent properties that do not cause deterioration of near-infrared absorption, layer discoloration, surface quality, etc. There is versatility that can be used as an adhesive layer for various functional transparent bodies such as films, and this functional film with a near-infrared absorbing adhesive layer is further bonded to another functional transparent body via this adhesive layer. Since the optical filter can be manufactured, it is possible to efficiently produce an optical filter having multifunctional optical characteristics, and can sufficiently cope with the above-described problems.

  The near-infrared absorbing pressure-sensitive adhesive film of the present invention contains a diimonium salt compound represented by the formula (1) obtained from a diimonium cation having two near-infrared absorbing ability and two trialkylsulfonyl carbanions in the pressure-sensitive adhesive layer, and is peeled off. It is a film characterized by being sandwiched between films, and absorbs near infrared rays in a wavelength range of 700 to 1100 nm well.

In the formula (1), R _{9 to} R ₁₁ each independently represent an aliphatic hydrocarbon group which may have a halogen atom. Examples of the aliphatic hydrocarbon group include saturated and unsaturated linear and branched alkyl groups, preferably having 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms. As the halogen atom, fluorine, chlorine or bromine is preferable, and a fluorine atom is most preferable. Specific examples of R _{9 to} R ₁₁ include methyl, trifluoromethyl, difluoromethyl, dichloromethyl, dibromomethyl, difluorochloromethyl, ethyl, pentafluoromethyl, tetrafluoroethyl, tri Saturated linear alkyl group such as fluoroethyl group, difluoroethyl group, monofluoroethyl group, hexafluoropropyl group, pentafluoropropyl group or perfluorobutyl group, allyl group, tetrafluoroallyl group, trifluorovinyl group or perfluorobutyl An unsaturated alkyl group such as a vinyl group, a branched alkyl group such as an isopropyl group, a pentafluoroisopropyl group, or a perfluoro-3-methylbutyl group, and the like are exemplified, and all of R _{9 to} R ₁₁ are preferably the same group.

Of these, those in which all of R _{9 to} R ₁₁ are aliphatic hydrocarbon groups having a fluorine atom are preferred, and in particular, all of R _{9 to} R ₁₁ are trifluoromethyl, difluoromethyl, pentafluoro Those which are an ethyl group, a trifluoroethyl group, a heptafluoropropyl group, a tetrafluoropropyl group or a perfluorobutyl group are preferable, and a trifluoromethyl group is more preferable. Each of the above alkyl groups means a straight chain unless otherwise specified.

R _{1 to} R ₈ each independently represent a hydrogen atom or an aliphatic hydrocarbon group which may have a substituent, and preferably has 1 to 10 carbon atoms, more preferably 3 to 5 carbon atoms. The aliphatic hydrocarbon group means a group obtained by removing one hydrogen atom from a saturated or unsaturated linear or branched aliphatic hydrocarbon.

Specific examples of the aliphatic hydrocarbon group having no substituent include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, ter-butyl group, and n-pentyl group. A linear or branched saturated aliphatic hydrocarbon group or unsaturated aliphatic hydrocarbon group such as iso-pentyl group, ter-pentyl group, vinyl group, allyl group, propenyl group or pentynyl group, and a substituent Specific examples of the aliphatic hydrocarbon group having an aliphatic hydrocarbon group such as 2-cyanoethyl group, 3-cyanopropyl group, 4-cyanobutyl group, 3-methoxypropyl group or 4-methoxybutyl group Of these, at least one of R _{1 to} R ₈ is preferably a branched alkyl group, particularly an all alkyl group branched at the terminal, and more preferably a carbon having a branched terminal. Alkyl groups having 3 to 5 are more preferable, and all of R _{1 to} R ₈ are particularly preferably iso-butyl groups.

  In the present invention, the diimonium salt compound represented by the formula (1) can be obtained, for example, according to the method described in Patent Document 5. That is, the following formula (2) obtained by reducing the product obtained by the Ullmann reaction of p-phenylenediamine and 1-chloro-4-nitrobenzene

In an organic solvent, preferably in a water-soluble polar solvent such as DMF (dimethylformamide), DMI (dimethylimidazolidinone), or NMP (N-methylpyrrolidone) at 50 to 140 ° C. A compound in which all substituents are the same by reacting with a halogenated compound corresponding to R _{1 to} R ₈ (for example, iso-C ₄ H ₉ Br when R _{1 to} R ₈ is an iso-butyl group) (3)) can be obtained. Further, when the substituents of R _{1 to} R ₈ are different, for example, when four are n-butyl groups and the remaining four are iso-butyl groups, a predetermined number of moles per mole of the compound of the formula (2) reagents, after introducing n- butyl group into four amino groups in this case reacted with 4 moles of n-C 4 _H 9 _Br, moles of reagents necessary to introduce the remaining substituents, the In some cases, by reacting with 4 moles of iso-C ₄ H ₉ Br, a compound of formula (3) in which 4 are n-butyl groups and the remaining 4 are iso-butyl groups can be produced.

(In formula (3), R _{1 to} R ₈ represent the same meaning as in formula (1).)

  The compound of formula (3) synthesized above is oxidized in an organic solvent such as DMF, DMI or NMP at 0 to 100 ° C., preferably at 5 to 70 ° C., corresponding to the following formula (4) (for example, silver salt) Is added to carry out an oxidation reaction. The compound of formula (3) synthesized above is oxidized with an oxidizing agent of silver nitrate, silver perchlorate, or cupric chloride, and then an anion acid or salt of formula (4) is added to the reaction solution to react. By doing so, the diimonium salt compound represented by the formula (1) can be synthesized.

 Although the specific example of the diimonium salt compound shown by Formula (1) which can be used for the near-infrared absorption filter of this invention at Table 1 is given, it is not necessarily limited to these.

Table 1 Specific examples of diimonium salt compounds

In the column of (R _{1 to} R ₈ ) in Table 1, the group described in () is a group bonded to a nitrogen atom (n- means normal, i- means iso), and “4” is 4 It means that each nitrogen atom is substituted with the group described in (). In R ₉ , R ₁₀ and R ₁₁ , all of the alkylene parts having 3 or more carbon atoms are normal.

  The diimonium salt represented by the formula (1) used in the present invention may be contained alone in the adhesive layer, but other factors may be used depending on the desired near-infrared absorption wavelength range, absorption ratio, price, etc. It may be used in combination with one or more near infrared absorbing compounds (in the case of using this diimonium salt compound in combination with other near infrared absorbing compounds, it is referred to as “this near infrared absorbing compound”), and other near infrared absorbing Examples of such compounds are nitroso compounds and their metal salts, cyanine compounds, squarylium compounds, thiol nickel complex compounds, phthalocyanine compounds, naphthalocyanine compounds, triallylmethane compounds, naphthoquinone compounds or anthraquinone compounds Such as hexaboride of rare earth metals such as lanthanum, cesium, antimony tin oxide and indium tin oxide. Compounds, and the like, but solvent solubility and, it is necessary to heat resistance at the adhesive layer, the compound which is excellent in durability light resistance are selected. Of these, phthalocyanine compounds are suitable in terms of stability and solvent solubility. Specifically, compounds described in Patent Document 4 and Patent Document 7 fall under this category, and those that can be easily obtained from the market are Japan. Examples include “e-ex color” series manufactured by Catalyst Co., Ltd. and “YKR” series manufactured by Yamamoto Kasei Co., Ltd.

Hereinafter, a method for incorporating the present diimonium salt compound or the present near-infrared absorbing compound into the adhesive layer will be described.
The binder resin that is the main component of the adhesive layer contains the diimonium salt compound or the near-infrared absorbing compound uniformly and can be held on the surface of the release film as an adhesive layer, and adheres to the functional transparent body via the adhesive layer. Although it is not particularly limited as long as it can be pressure-bonded well and does not impair the functions of the filter, an adhesive such as acrylic, polyester, polyamide, polyurethane, polyolefin, polycarbonate, rubber, or silicon resin is used. Although mentioned, an acrylic resin adhesive material is suitable at the point which is excellent in transparency, adhesiveness, heat resistance, etc. Acrylic resin adhesive is mainly composed of acrylic acid alkyl ester with no functional group, and copolymerized with other monomer components other than acrylic acid alkyl ester having functional group and acrylic acid alkyl ester. It has been made. There is no need for a binder resin of a type that is cured by energy rays such as ultraviolet rays as in Patent Document 8, but ultraviolet irradiation is not preferable because it may cause alteration of the adhesive layer.
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-ter-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 monomers, for example, hexamethylene diisocyanate, aliphatic diisocyanate such as trimethylene propane adduct of hexamethylene diisocyanate, tolylene diisocyanate or trimethylol propane addition of tolylene diisocyanate. Polyisocyanate compounds such as aromatic diisocyanates, butyl etherified styrol melamine, melamine compounds such as trimethylol melamine, diamine compounds such as hexamethylene diamine or triethyl diamine, epoxy resin compounds such as bisphenol A and epichlorohydrin, urea resin A compound, a metal salt such as aluminum chloride, ferric chloride, or aluminum sulfate is used, and its blending amount is usually 100 parts by weight of acrylic resin. 0.005-5 parts by weight, preferably about 0.01 to 3 parts by weight.
Acrylic resin adhesives have excellent adhesion and cohesion, and because they have no unsaturated bonds in the polymer, they are highly stable to light and oxygen, and because they have a high degree of freedom in selecting monomer types and molecular weights. It is preferred to use. The pressure-sensitive adhesive has a high molecular weight (degree of polymerization) in order to maintain adhesion to the functional transparent body, that is, the weight average molecular weight (Mw) of the main polymer is preferably about 600,000 to 2,000,000, more preferably 80 It is about 10,000 to 1.8 million.

  In addition to the resin component, the adhesive layer contains a stabilizer and an ultraviolet absorber for preventing deterioration of the adhesive layer over time, a dye compound for adjusting the color tone, and a metal on the adherend surface of the functional transparent body at the time of use. When it contains, an antioxidant etc. are contained as needed.

  In order to prevent deterioration of the adhesive layer over time, it is fundamental to select materials that do not easily deteriorate for each material contained in the adhesive layer, including the near-infrared absorbing compound. A layer such as a functional transparent body that receives external light on the viewer side from the layer is allowed to retain ultraviolet absorptivity, or an ultraviolet absorber and / or a hindered amine light stabilizer as disclosed in Patent Document 4 is used. It is necessary to make it contain in the adhesion layer.

  The dye compound that is contained in the adhesive layer and adjusts the color tone is an orange light emission having a wavelength of 550 to 620 nm (hereinafter referred to as neon light because it is derived from neon gas), which causes a decrease in the color purity of red light generated upon application of voltage in the PDP. Neon light-absorbing compound for cutting off) and power-off state color screens such as neutral gray and neutral blue are preferred color-adjusting coloring compounds such as azaporphyrin, cyanine, squarylium, azomethine , Xanthene, oxonol, or azo compounds, and the neon light-absorbing compound is a tetraaza having a maximum absorption wavelength at a wavelength of 550 to 620 nm from the viewpoint of heat resistance and heat and humidity resistance in the adhesive layer. Porphyrin compounds are more preferred.

  When metal is included in the adherend surface of the functional transparent body in use, a mesh type electromagnetic wave in which ultrafine wires of metal such as copper are held on a transparent support in a geometric pattern like a mesh (mesh) When the shielding film is applicable and the metal of the mesh is not covered with synthetic resin, the adhesive layer will discolor over time due to the reaction of the metal and acid substances in the adhesive layer when in contact with the adhesive layer. Therefore, it is necessary to contain an antioxidant in the adhesive layer or to make it an adhesive layer containing as little acid substance as possible, and the antioxidant is not particularly limited, but 2-aminopyridine, 2-aminopyrimidine Rust inhibitors such as 2-aminoquinoline, aminotriazine or aminotriazole and substituted derivatives thereof, benzotriazole compounds, phenyltetrazole, 2-aminotrithiazole, etc. Ri is suitable, depending on the respective conditions, with respect to general adhesive layer after the adhesive coating, 0.01 to 10 wt%, preferably 0.05 to 5% by weight is used. In addition, as the acid substance in the adhesive layer, the amount of organic acid substances such as carboxyl group-containing monomers such as acrylic acid and maleic acid used in the adhesive can be suppressed as much as possible, and if necessary, a purification step is added to the adhesive layer. Discoloration of the adhesive layer can be suppressed by adjusting the content of these organic acid monomers in the mixture to 0.5% by weight or less.

  The release film used in the present invention may be a thin film material that can hold an adhesive layer on its surface and can be easily peeled off when the adhesive layer is used. The material may be synthetic resin or paper, or synthetic resin and paper. Can be used, and a silicone polymer is used on the surface to give the peelability with controlled release force, but it is more transparent than the release paper because the defect of the adhesive layer can be checked from above the release film. A synthetic resin release film is preferred for use. As a synthetic resin that can be used, a transparent polyester-based (hereinafter referred to as PET), polycarbonate-based, triacetate-based, norbornene-based, acrylic-based, cellulose-based, polyolefin-based or urethane-based polymer resin film is suitable. PET is preferred and commonly used frequently. As thickness, 10-200 micrometers, More preferably, 20-100 micrometers can be used.

  The silicone polymer for imparting peelability to the film is not particularly limited, and may be either a condensation type or an addition type, and may be subjected to silicone treatment after pre-priming the film to improve adhesion. Examples of release films available from the market include Diafoil PET series (MR, MRA, MRF, etc.), Lintec PET series (3811, 38GS, 38V1, 38A, 38R, etc.) and the like. In addition, the near-infrared absorbing pressure-sensitive adhesive can be applied to a release film and wound as it is, and can be sandwiched between both sides of a single release film. In this case, a release film having both sides peelable is used. .

  This dimonium salt compound or near-infrared absorbing compound is a binder resin, a polymerization initiator, a crosslinking agent, a UV absorber, a light stabilizer, a color tone adjusting dye, an oxidation agent, which are used as necessary. Dissolve or disperse sufficiently in a solvent such as methyl ethyl ketone (MEK) together with an inhibitor and other additives to form a pressure-sensitive adhesive, and on the surface of the release film, the layer thickness after drying is 5 to 100 μm, preferably 10 to 50 μm. Apply as follows. The coating method is not particularly limited, and it is applied with a bar coater, reverse coater, comma coater, or gravure coater, etc., dried and fixed with an adhesive layer on the top while fixing the adhesive layer. There are a method of winding an adhesive layer with a release film, and a method of winding an adhesive layer on one side of a double-sided release film and winding it with a single release film as it is after drying. The near-infrared absorption filter of the present invention is preferably designed so that the transmittance of near-infrared light having a wavelength of 700 to 1100 nm is 10% or less, and the present diimonium salt compound or the present near-infrared absorptive compound has an amount corresponding thereto. What is necessary is just to use it, and what is necessary is just to make it contain in an adhesive liquid agent so that it may become about 1 to 20 weight% with respect to an adhesion layer.

  When adhering the adhesive layer of the near-infrared absorbing adhesive film of the present invention to a functional transparent body, the release film on one side holding the adhesive layer is peeled off and pressure-bonded to the functional transparent body, and the remaining release film is peeled off. However, it is easier to work if the release films on both sides of the sandwiched film have different peelability, and the peelable release film is peeled off first to adhere the functional transparent body. An optical filter having a plurality of functions can be easily manufactured by pressure-bonding to the surface and then peeling the other release film having a stronger peeling force and pressure-bonding to a surface to be bonded such as an object to be bonded. Further, when the adhesive layer is applied, it is generally applied to the surface having a higher peel force, and a release film having a weak peel force is pressure-fixed and wound. In the case of using one double-sided peelable film, a method of coating on the surface having the strong peeling force and winding it with the adhesive layer inside is preferable. The peeling force may be selected in the range of 5 to 1000 mN / cm, more preferably 10 to 200 mN / cm. In addition, the measurement of the peeling force of the peeling film used for this invention is Nitto Denko Co., Ltd. double-sided tape No. 502 was affixed to a glass plate, and a release film was pressure-bonded thereon, peeled at an angle of 180 ° and a speed of 300 mm / min, and the peel strength was measured.

  The functional transparent body used when the optical filter for PDP of the present invention is produced using the near-infrared absorbing adhesive film of the present invention includes an electromagnetic wave shielding film, an anti-reflection film, a module protective substrate (glass, plastic). Etc. The electromagnetic shielding film has a mesh type in which ultrafine wires of metal such as copper are held on a transparent support in a geometric pattern like a mesh, and an ultrathin film is held on a transparent support in a range having visible light transmittance. There is a thin-film type, and the thin-film type normally reflects near-infrared light and does not transmit it to the viewer side. Therefore, a near-infrared absorbing filter is not required, so the near-infrared absorbing adhesive film of the present invention is a mesh-type electromagnetic wave shielding film Used for. Even when mesh-type electromagnetic shielding film is applied to a transparent support with a metal foil such as copper on a transparent support, the surface of the copper foil is roughened and transparently supported with an adhesive to ensure good adhesion. After being bonded to the body, it is manufactured by a method in which only the lattice lines are left behind by etching, and the other portions are dissolved and removed. Therefore, the rough surface of the copper foil is transferred to the solidified adhesive surface on the transparent support. Lack of transparency. For this reason, the polymer resin is treated from above to make it smooth and transparent, but the transparency treatment also causes an increase in cost and is therefore omitted. The pressure-sensitive adhesive layer of the pressure-sensitive adhesive film containing the antioxidant of the present invention has a mesh-type electromagnetic wave shielding film having a metal lattice surface (hereinafter referred to as a mesh surface) such as copper on the surface, that is, this transparent treatment. It is applied to the electromagnetic wave shielding film that has not been applied. After peeling one release film of the adhesive film of the present invention on the mesh surface, the adhesive layer is pressure-bonded, and the antireflection film or glass substrate is pressure-bonded to the opposite side. Thus, an optical filter for PDP is obtained. It was found that the adhesive surface in the rough state can be made transparent by pressure-bonding the pressure-sensitive adhesive layer, and more rational production is possible. In addition, since the transparency improves when the refractive index of the pressure-sensitive adhesive layer is closer to the refractive index of the rough surface adhesive layer, such considerations are necessary for the formulation of the pressure-sensitive adhesive.

  Anti-reflective film is a film with a low refractive index and a transparent support with a low refractive index agent coated with a polymer resin binder and other additives on the surface of a transparent support such as PET to suppress reflection of light from the outside. A hard coat layer and a high refractive index layer are applied between the layers, and the reflection is reduced by controlling to cancel the reflected light from each layer, improving the visibility. Anti-glare and anti-reflection films are anti-reflection films These films are made by adding fine particles to the high refractive index layer and other layers to diffusely reflect light from the outside to further improve the visibility. As these anti-reflection films, the arc top series (made by Asahi Glass), Kaya Coat ARS Series (manufactured by Nippon Kayaku), Kayacoat AGRS series (manufactured by Nippon Kayaku), Realak series (manufactured by Nippon Oil & Fats), etc. can be obtained from the market.

The near-infrared absorbing adhesive film of the present invention has an adhesive layer that is pressure-bonded to a functional transparent body to combine the functions into an optical filter. However, even when directly bonded to a PDP module, a transparent glass plate or plastic plate May be attached to the front surface of the PDP. The mesh end face of the electromagnetic wave shielding film should be grounded.
Although an example of the structure of the optical filter for PDP of this invention which uses the near-infrared absorptive adhesive film of this invention below is described, it is not necessarily restricted to these. NIR represents near-infrared light, Ne represents neon light, UV represents ultraviolet light, and the part enclosed in parentheses indicates the pressure-sensitive adhesive layer of the near-infrared absorbing adhesive film of the present invention. In addition, it can be seen that the near-infrared absorbing film of the present invention is versatile and convenient for producing an optical filter for PDP.

(1) UV-absorbing anti-reflection film / (NIR / Ne absorption / color adjusting adhesive layer) / electromagnetic wave shielding film / adhesive layer ⇒ Directly pasted on the front surface of the PDP module. (2) UV-absorbing anti-reflection film / (NIR / Ne absorption / color-adjusting adhesive layer) / electromagnetic wave shielding film / adhesive layer / glass substrate → attached to the front surface of the PDP module. (3) Anti-reflective film / UV absorbing adhesive layer / electromagnetic wave shielding film / (NIR / Ne absorption / color adjusting adhesive layer) ⇒Directly attached to the front surface of the PDP module. (4) Reduced reflection film / UV absorbing adhesive layer / electromagnetic wave shielding film / (NIR / Ne absorption / color adjusting adhesive layer) / glass substrate⇒attached to the front surface of the PDP module. (5) Glass substrate / (NIR / Ne absorption / color adjusting adhesive layer) / electromagnetic wave shielding film => attached to the front surface of the PDP module.

  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”.

Example 1
(Synthesis Example 1 of diimonium salt compound)
After adding 4 parts of N, N, N ′, N′-tetrakis (p-di (iso-butyl) aminophenyl) -p-phenylenediamine in 20 parts of DMF and dissolving by heating at 60 ° C., tris (trifluoromethanesulfonyl) ) Add 8 parts of 58.4% carbonic acid aqueous solution (manufactured by 3M). Subsequently, 1.6 parts of silver nitrate dissolved in 23.5 parts of DMF was added, and the mixture was heated and stirred for 30 minutes. After filtering the insoluble matter, water and methanol were added to the reaction solution, and the precipitated crystals were filtered, washed with methanol, washed with water, and dried. All of R _{1 to} R ₈ in formula (1) were iso-butyl groups. 7 parts of Compound No. 2 in Table 1 were obtained.
λmax; 1109 nm (dichloromethane), molar extinction coefficient (ε); 107000

A coating solution prepared by mixing and dissolving the respective adhesive materials shown in Table 2 below in a uniform manner was used as a release film A (trade name: Diafoil MR-38; Mitsubishi Chemical Corporation) having a peeling force of 25 mN / cm, a thickness of 38 μm, and a width of 1300 mm. Polyester Film Co., Ltd.) is coated with a comma coater at a drying temperature of 0.8 m / min and a drying temperature of 110 ° C. so that the adhesive layer has a thickness of 18 μm and dried. A release film B having a thickness of 38 μm and a width of 1300 mm (trade name Diafoil MRF-38; manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.) is roll-bonded and wound on a plastic core having an outer diameter of 60 inches to absorb near infrared rays and neon light. A near-infrared absorbing pressure-sensitive adhesive film of the present invention having a color adjusted to neutral blue was obtained.
Further, the release film B of this film is peeled off, and the adhesive layer is roll-bonded to the surface of Kayacoat ARS-D501-100UV (manufactured by Nippon Kayaku Co., Ltd.) which is a UV-absorbing anti-reflection film, and then peeled off. Anti-reflective film / (NIR · Ne) which peels off film A, is roll-bonded to electromagnetic wave shielding film 1 and has anti-reflection, near-infrared absorptivity, neon light absorptive color adjusted to neutral blue An optical filter for PDP of the present invention having a constitution of absorption / color adjusting pressure-sensitive adhesive layer) / electromagnetic wave shielding film 1 and simple production and excellent optical performance was obtained. The optical filter is used by being directly attached to the front surface of the PDP module, or attached to the front surface of the PDP module by being attached to a glass substrate.

Table 2
Materials Amount used Diimonium salt compound of Compound No. 2 1.0 part neon light absorber (trade name TAP-2; manufactured by Yamada Chemical Industry Co., Ltd.) 0.096 part UV absorber (trade name Tinuvin 109; manufactured by Ciba Geigy) 1.2 Part yellow dye (trade name KAKASET Yellow GN) 0.006 parts blue dye (trade name KAYASET Blue N) 0.0072 parts acrylic resin (trade name PTR-2500T; manufactured by Nippon Kayaku) 120.0 parts hardener (product) Name M12ATY; manufactured by Nippon Kayaku Co., Ltd. 0.324 parts curing agent (trade name L45EY; manufactured by Nippon Kayaku Co., Ltd.) 0.444 parts curing agent (trade name C-50; manufactured by Soken Chemical Co., Ltd.) 0.142 parts methyl ethyl ketone 84.0 parts (Ii) Trade name TAP-2; Tetraazaporphyrin compound, trade name Tinuvin 109; Benzotriazole compound, yellow index (color index) ; Solvent Yellow 93, a blue dye (color index); Solvent Blue 35, trade name M12ATY; metal chelate compound, trade name L45EY; isocyanate compound, trade name C-50; a silane coupling agent

(Preparation of electromagnetic wave shielding film 1)
Using a 50 μm thick PET film (trade name Cosmo Shine A-4100; manufactured by Toyobo Co., Ltd.), an epoxy resin adhesive sheet (Nikaflex SAF; manufactured by Nikkan Kogyo Co., Ltd., 20 μm) serving as an adhesive layer is formed on the PET film. The electrolytic copper foil having a rough surface with a thickness of 18 μm, which is a material, was heat-laminated and bonded under the conditions of 180 ° C. and 30 kgf / cm 2 so that the rough surface was on the epoxy resin adhesive sheet side. The resulting PET film with copper foil undergoes a photolithography process (resist film bonding-exposure-development-chemical etching-resist film peeling) to form a copper lattice pattern with a line width of 25 μm and a line interval of 500 μm on the PET film, As a transparent treatment on the copper lattice pattern surface, an adhesive obtained by uniformly mixing the adhesive composition shown in Table 3 is applied so as to have a dry coating thickness of about 40 μm and dried to obtain an electromagnetic wave shielding film 1 having transparency. It was.

Table 3
Material Amount used TBA-HME (manufactured by Hitachi Chemical Co., Ltd .: polymer epoxy resin) 100 parts YD-8125 (manufactured by Tohto Kasei Co., Ltd .: bisphenol A type epoxy resin) 25 parts IPDI (manufactured by Hitachi Chemical Co., Ltd .: Max isocyanate) 12 .5 parts 2-ethyl-4-methylimidazole 0.3 parts MEK 300 parts cyclohexanone 15 parts

Example 2
In the same manner as in Example 1, the pressure-sensitive adhesive film of the present invention which absorbed near infrared rays and neon light and was color-adjusted to neutral blue was obtained. Further, the release film B of this film is peeled off, and an adhesive layer is roll-bonded to the electromagnetic wave shielding film 1, and then Kayacoat ARS, which is a reduced reflection film with an UV absorbing adhesive layer on the surface opposite to the adhesive layer of the electromagnetic wave shielding film 1. -D250TG-125 (manufactured by Nippon Kayaku Co., Ltd.) is roll-bonded via the adhesive layer, has reduced reflection, near infrared absorption, neon light absorption, and is color-adjusted to neutral blue An optical filter for PDP having a structure of a reflection film / electromagnetic wave shielding film 1 / (NIR / Ne absorption / color adjusting adhesive layer), which is easy to manufacture and excellent in optical performance, was obtained. This optical filter is used by being directly attached to the front surface of the PDP module through the NIR / Ne absorption / color adjusting adhesive layer, or attached to the front surface of the PDP module by being attached to a glass substrate.

Example 3
Near-infrared and neon light absorptivity in the same manner as in Example 1 except that 0.067 parts of the antioxidant 1H-benzotriazole was added to the adhesive material shown in Table 2 and mixed and dissolved. The near-infrared absorptive pressure-sensitive adhesive film of the present invention containing an antioxidant was obtained.
The near-infrared-absorbing pressure-sensitive adhesive film is peel-bonded to a surface that is not subjected to the anti-reflection treatment of Kayacoat ARS-D501-100UV (manufactured by Nippon Kayaku Co., Ltd.). Adhere the layers, then peel off the other release film A, roll press-bond to the mesh surface of the electromagnetic wave shielding film 2, have reduced reflection, near infrared absorption, neon light absorption, color adjustment to neutral blue Thus, an optical filter for PDP having a structure of a reduced reflection film / (NIR / Ne absorption / color-adjusting adhesive layer) / electromagnetic wave shielding film 2 with simple production and excellent optical performance was obtained. This optical filter is used by directly attaching it to the front surface of the PDP module or attaching it to a glass substrate and attaching it to the front surface of the PDP module.

(Preparation of electromagnetic wave shielding film 2)
Conductive material using a PET film (trade name Cosmo Shine A-4100; manufactured by Toyobo Co., Ltd.) having a thickness of 100 μm and an epoxy adhesive sheet (Nikaflex SAF; manufactured by Nikkan Kogyo Co., Ltd., 20 μm) serving as an adhesive layer thereon. The electrolytic copper foil having a thickness of 18 μm and having a rough surface was bonded by heating lamination under conditions of 180 ° C. and 30 kgf / cm 2 so that the rough surface was on the epoxy adhesive sheet side. A copper lattice pattern having a line width of 25 μm and a line interval of 500 μm is formed on the PET film through a photolithography process (resist film bonding-exposure-development-chemical etching-resist film peeling) on the obtained PET film with copper foil. An electromagnetic wave shielding film 2 having some transparency was obtained.

Example 4
The acrylic resin (trade name PTR-2500T; manufactured by Nippon Kayaku Co., Ltd.) as the adhesive material shown in Table 2 is used except that an acrylic acid resin without addition of organic acid (trade name PTR-5500; manufactured by Nippon Kayaku Co., Ltd.) is used. Obtained the near-infrared absorptive filter of this invention which has the near-infrared absorptivity and neon light absorptivity which do not add an organic acid to an adhesion layer by the method similar to Example 1. FIG.
The release film B of this film is peeled off, and a near-infrared absorbing adhesive layer is rolled on the surface of the Kayacoat ARS-D501-100UV (manufactured by Nippon Kayaku Co., Ltd.) which is a UV-absorbing reduced reflection film. Then, the other release film A was peeled off and roll-bonded to the mesh surface of the electromagnetic wave shielding film 2 to have a low reflection property, a near infrared absorption property, and a neon light absorption property, and the color was adjusted to neutral blue. Thus, an optical filter for PDP having a structure of a reduced reflection film / (NIR / Ne absorption / color adjusting adhesive layer) / electromagnetic wave shielding film 2 and simple in production and excellent in optical performance was obtained. The optical filter is used by being directly attached to the front surface of the PDP module, or attached to the front surface of the PDP module by being attached to a glass substrate.

Example 5
In the raw materials for pressure-sensitive adhesives shown in Table 2, the same raw materials as in the table are used except that the neon light absorber, the yellow dye and the color adjusting dye compound of the blue dye are not used. An inventive near-infrared absorbing adhesive film was obtained.

Example 6
(Synthesis Example 2 of diimonium salt compound)
Instead of N, N, N ′, N′-tetrakis (p-di (iso-butyl) aminophenyl) -p-phenylenediamine in Synthesis Example 1, N, N, N ′, N′-tetrakis (p-dikis Except for the use of (n-butyl) aminophenyl) -p-phenylenediamine, all of R _{1 to} R _{8 in} formula (1) are n-butyl groups and the anion is tri ( 7 parts of the diimonium salt compound of Compound No. 1 in Table 1 which is a fluoromethane) carbanion was obtained.
λmax; 1101 nm (dichloromethane), molar extinction coefficient (ε); 107000
The near-infrared absorption of the present invention in which the PET film is a transparent support and the adhesive layer has near-infrared absorptivity in the same manner as in Example 4 except that the diimonium salt compound of Synthesis Example 2 is used instead of the compound of Synthesis Example 1 A filter was obtained.

Control 1
Near-infrared absorption in the adhesive layer sandwiched between the release films in the same manner as in Example 4 except that a diimmonium salt compound of the following formula (5) is used instead of the diimmonium salt compound of Compound No. 1 in Table 1. The comparative near-infrared absorptive adhesive film which has property was obtained.

Control Example 2
Comparative near-infrared absorbing adhesive sandwiched between release films in the same manner as in Example 4 except that a diimmonium salt compound of the following formula (6) is used instead of the diimmonium salt compound of Compound No. 1 in Table 1. A film was obtained.

Control 3
Comparative near-infrared absorptivity sandwiched between release films in the same manner as in Example 4 except that a diimmonium salt compound of the following formula (7) is used instead of the diimmonium salt compound of Compound No. 1 in Table 1. An adhesive film was obtained.

(performance test)
The near-infrared absorbing adhesive films of Examples 5 to 6 and Control Examples 1 to 3 were tested for heat resistance and moist heat resistance.
Since the characteristics of the heat resistance and moist heat resistance of the dimonium salt compound are manifested as changes in the absorptive power in the visible light ray and near infrared ray (wavelength 700 to 1100 nm) at a wavelength of 400 to 480 nm, in this wavelength region (select 3 wavelengths). The change in absorption capacity was measured. That is, the release film B of each test piece of the example and the control example was peeled and the adhesive layer was pressure-bonded to a float glass having a thickness of 1 mm. The heat resistance test was 80 ° C., the moist heat resistance test was 60 ° C., and the relative humidity was 90%. After being left in the constant temperature / humidity bath for 94 hours, the light transmittance at three wavelengths (430 nm, 880 nm, and 980 nm) before and after the test was measured and the appearance of the adhesive layer was observed.
Tables 4 and 5 show the appearance observation results and the change in transmittance at each wavelength (transmittance after test (%) at each wavelength−transmittance before test (%)).

  As can be seen from the results of Tables 4 and 5, both the heat resistance and the heat and humidity resistance of the test pieces of Example 5 and Example 6 are more uneven than the test pieces of Control Example 2 and Control Example 3. In addition, the change at the wavelength of 430 nm is less than those of the control example 2 and the control example 3, and this is the cause of the good appearance change. On the other hand, the near-infrared absorptivity of the test piece of Control Example 1 was significantly reduced. The diimonium salt compound of Compound No. 2 in Example 5 was particularly superior to the diimmonium salt compound of Compound No. 1 in Example 6 with less change in transmittance at each wavelength and no change in appearance.

Table 4
Test example 1 (heat resistance)
Change in transmittance (%)
430nm 880nm 980nm Appearance of adhesive layer
Example 5 -1 1 0 Light brown, no change Example 6 -4 8 8 Light brown, only slightly yellowish Control Example 1 6 42 43 Light brown, little change Control Example 2-15 5 4 Light yellowish brown Change, agglomerate and unevenness generation control example 3-25 8 4 Change to light yellowish green, unevenness generation, a lot of aggregates

Table 5
Test Example 2 (Moisture and heat resistance)
Change in transmittance (%)
430nm 880nm 980nm Appearance of adhesive layer
Example 5 -1 0 0 Pale brown, no change Example 6 -4 9 8 Pale brown, only slightly yellowish Control Example 1 4 48 47 Pale brown, little change Control Example 2-15 5 4 Pale yellowish brown Change, agglomerate and unevenness generation control example 3-25 8 4 Change to light yellowish green, unevenness generation, a lot of aggregates

Claims (12)

A near-infrared absorptive adhesive film, wherein an adhesive layer containing a diimonium salt compound represented by the formula (1) is sandwiched between release films.

(In formula (1), R ₁ to R ₈ each independently represents an aliphatic hydrocarbon group which may have a hydrogen atom or a substituent, and R ₉ to R ₁₁ each independently have a halogen atom. Each represents an optionally substituted aliphatic hydrocarbon group.) The near-infrared absorptive adhesive film according to claim 1, wherein at least one of R ₁ to R _{8 in} the formula (1) is a branched alkyl group. The near-infrared absorptive adhesive film according to claim 2, wherein all of R ₁ to R _{8 in} the formula (1) are branched alkyl groups. The near infrared ray absorbing pressure-sensitive adhesive film according to claim 3, wherein all of R ₁ to R _{8 in} the formula (1) are iso-butyl groups. The near-infrared absorptive pressure-sensitive adhesive film according to claim 3, wherein all branched alkyl groups are alkyl groups having 3 to 5 carbon atoms branched at the ends. The near-infrared absorbing pressure-sensitive adhesive film according to any one of claims 1 to 5 all R ₉ - R ₁₁ is an aliphatic hydrocarbon group having a fluorine atom in the formula (1). The near-infrared-absorbing pressure-sensitive adhesive film according to claim 6, wherein all of the aliphatic hydrocarbon groups having a fluorine-containing atom are trifluoromethyl groups. The near-infrared absorbing pressure-sensitive adhesive film according to any one of claims 1 to 7, the antioxidant in the adhesive layer is contained. The near-infrared absorbing pressure-sensitive adhesive film according to any one of claims 1 to 8 the amount of organic acid is 0.5 wt% or less contained in the adhesive layer. The near-infrared absorbing according to any one of claims 1 to 9, the compound having an absorption maximum in a wavelength 550~620nm is characterized in that it is contained in the adhesive layer together with the diimmonium salt compound of formula (1) Adhesive film. The near-infrared absorbing pressure-sensitive adhesive film according to any one of claims 1 to 10 in which the release force of sandwiching the both release film surface of the adhesive layer are different from each other each of the release films that sandwich the adhesive layer. PDP optical filter for characterized by having a near-infrared absorbing adhesive layer according to any one of claims 1 to 11.