JP2008026727A - Optical film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical film excellent in heat and moisture resistances and optical characteristics, in particular, excellent in moisture resistance even when a resin constituting a near-infrared absorption layer has a low glass transition temperature. <P>SOLUTION: The optical film has a near-infrared absorption layer containing a compound represented by formula (1) and a resin, wherein R<SP>1</SP>-R<SP>8</SP>are each an isobutyl group, X<SP>-</SP>is (R<SP>f</SP>SO<SB>2</SB>)<SB>3</SB>C<SP>-</SP>, and R<SP>f</SP>is a 1-4C fluoroalkyl group. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical film having near infrared absorption ability.

The principle of a plasma display panel (hereinafter referred to as “PDP”) is that a voltage is applied to a rare gas (helium, neon, argon, xenon, etc.) sealed between two sheet glasses, and ultraviolet rays generated at that time are applied. Visible light is generated by being applied to a light emitter.
From the PDP, near-infrared rays, electromagnetic waves and the like are radiated simultaneously with visible rays. For example, near infrared rays have a negative effect when data is transferred to a point-of-sale (POS) system or the like by malfunctioning a near infrared remote control for home appliances such as a home TV, cooler, or video deck, or malfunctioning a communication device. Or Therefore, it is necessary to install an optical filter that blocks near-infrared rays on the front surface (viewing side) of the PDP.

As an optical filter, an optical film that blocks near infrared rays having a wavelength of 800 to 1000 nm has been proposed.
As an optical film, for example, there is an optical film in which a near-infrared absorbing layer in which a pigment that absorbs near-infrared is dispersed in a transparent resin is formed on a substrate made of polyethylene terephthalate (PET) or the like. Various dyes such as polymethine dyes, metal complex dyes, squalium dyes, cyanine dyes and indoaniline dyes are known as dyes that absorb near infrared rays.

The diimonium dye is one of typical dyes that absorb near-infrared rays, and is used in near-infrared filters, heat insulating films, sunglasses, and the like.
However, diimonium dyes have a problem that they are weak against light, heat, moisture and the like, and easily deteriorate. When the dimonium dye deteriorates, it not only lowers the near-infrared absorptivity, but also causes discoloration, lowers the visible transmittance, and makes the eyes appear greenish. End up.

  An optical film having a near-infrared absorption layer in which a diimonium dye is blended in a transparent resin and having excellent heat resistance, moisture resistance, and optical properties has been proposed (Patent Document 1). Examples of the diimonium dye having heat resistance, moisture resistance, light resistance and the like include, for example, N, N, N ′, N′-tetrakis (p-dialkylaminophenyl) -p-phenylenediamine bis (bis (par Fluoroalkylsulfonyl) imidic acid) imonium salts and the like are known (Patent Document 2).

However, the inventor's investigation revealed that the specific diimonium dye described in Patent Document 1 may not have sufficient moisture resistance. When the moisture resistance is not sufficient, the optical film is discolored and the optical properties are deteriorated. Similarly, although the diimonium dye described in Patent Document 2 has good heat resistance, the moisture resistance is not sufficient.
The present inventor has found that the moisture resistance of the diimonium dye is related to the glass transition temperature (Tg) of the resin. When the glass transition temperature of the resin is sufficiently high, the resin has excellent moisture resistance, but when the glass transition temperature of the resin is low, the moisture resistance is insufficient.

When the glass transition temperature of the transparent resin is limited, for example, the following problems occur.
(I) When the glass transition temperature of the transparent resin is high, the near-infrared absorbing layer becomes hard, and the handling property and workability of the optical film are deteriorated.
(Ii) A resin having a low glass transition temperature, such as a pressure-sensitive adhesive, cannot be used in the near-infrared absorbing layer, and a near-infrared absorbing layer having the function of the pressure-sensitive adhesive layer cannot be obtained.
JP 2005-049848 A JP-A-2005-336150

  An object of the present invention is to provide an optical film which is excellent in heat resistance, moisture resistance and optical properties, and in particular, has excellent moisture resistance even when the glass transition temperature of the resin constituting the near infrared absorption layer is low.

  The optical film of the present invention has a near-infrared absorbing layer containing a compound represented by the following formula (1) and a resin.

^However, R 1 to R ⁸ is an isobutyl, X ^{- _{is, (R f SO 2) 3}} C - represents an anion represented by ^{R f} is represents a fluoroalkyl group having 1 to 4 carbon atoms.

The fluoroalkyl group is preferably a perfluoroalkyl group.
It is preferable that the near-infrared absorbing layer further contains a near-infrared absorbing dye other than the compound represented by the formula (1) having a maximum absorption wavelength (λ _max ) in the range of 800 to 1100 nm.
The near-infrared absorbing dye other than the compound represented by the formula (1) is preferably at least one near-infrared absorbing dye selected from an aminium dye and a cyanine dye.
The glass transition temperature (Tg) of the resin is preferably 80 ° C. or lower.

  The optical film of the present invention is excellent in heat resistance, moisture resistance and optical properties, and in particular, is excellent in moisture resistance even when the glass transition temperature of the resin constituting the near infrared absorption layer is low.

  In the present specification, a compound represented by the formula (1) is referred to as a compound (1). The same applies to compounds represented by other formulas.

<Optical film>
The optical film of this invention is a film which has a near-infrared absorption layer containing a compound (1) and resin.
The optical film of the present invention may be a film composed only of a near-infrared absorbing layer or a film in which a near-infrared absorbing layer is formed on a support film.

Since an optical film is normally arrange | positioned at visual recognition sides, such as PDP, the thing of an achromatic color is preferable. In the C light source standard calculated according to JIS Z 8701-1999, the chromaticity coordinates corresponding to the achromatic color are (x, y) = (0.310, 0.316). Preferably have chromaticity coordinates in the range of (x, y) = (0.310 ± 0.100, 0.316 ± 0.100). In order to obtain an optical film having the chromaticity coordinates, the type and content of the pigment may be appropriately selected.
The optical film of the present invention preferably has a luminous average transmittance of 45% or more, and particularly preferably satisfies the above chromaticity coordinate definition and the luminous average transmittance specification at the same time.

(Near-infrared absorbing layer)
A near-infrared absorption layer contains a compound (1) and resin.
The compound (1) is characterized in that R ^{1 to} R ⁸ are all isobutyl groups {(CH ₃ ) ₂ CHCH ₂ —} and X ⁻ is (R ^f SO ₂ ) ₃ C ^— .

R ^f is a fluoroalkyl group having 1 to 4 carbon atoms. R ^f is more preferably a fluoroalkyl group having 1 to 2 carbon atoms, and even more preferably a fluoroalkyl group having 1 carbon atom. When the carbon number is within the above range, durability such as heat resistance and moisture resistance and solubility in an organic solvent described later are good.

Examples of R ^f include perfluoroalkyl groups such as —CF ₃ , —C ₂ F ₅ , —C ₃ F ₇ , —C ₄ F ₉ , —C ₂ F ₄ H, —C ₃ F ₆ H, — C ₄ F ₈ H, and the like.
R ^f is particularly preferably a perfluoroalkyl group, and most preferably a trifluoromethyl group, since moisture resistance is further improved.

The molar extinction coefficient ε _m near 1000 nm of the compound (1) is preferably 0.8 × 10 ^{4 to} 1.0 × 10 ⁶ . The molar extinction coefficient ε _m is measured as follows.
Compound (1) is diluted with chloroform so that the sample concentration is 20 mg / L, and a sample solution is prepared. The absorption spectrum of this sample solution, using a spectrophotometer, measured in the range of 300～1300Nm, read the maximum absorption wavelength (lambda _max), the molar extinction coefficient at said maximum absorption wavelength (λ _max) (ε _m ) Is calculated from the following equation.
ε _m = ε / (c · d).
Where ε is an extinction coefficient, calculated as ε = −log (I / I ₀ ), I ₀ is the light intensity before incidence, I is the light intensity after incidence, and ε _m is the molar extinction coefficient. Where c is the sample concentration (mol / L) and d is the cell length.

The compound (1) preferably has a purity of 98% by mass or more in order to suppress deterioration during processing of the optical film and to provide practical durability after forming the optical film.
The compound (1) preferably has a melting point of 210 ° C. or higher in order to suppress deterioration during processing of the optical film and to provide practical durability after forming the optical film.
It is particularly preferable that the compound (1) has a purity of 98% by mass or more and a melting point of 210 ° C. or more.

Compound (1) can be synthesized, for example, as follows.
2 parts by mass of N, N, N ′, N′-tetrakis (p-aminophenyl) -p-phenylenediamine obtained by reducing the Ullmann reaction product of p-phenylenediamine and 1-chloro-4-nitrobenzene Is dissolved in 16 parts by mass of N, N-dimethylformamide, and 12 parts by mass of BrCH ₂ CH (CH ₃ ) ₂ is added thereto and reacted at 130 ° C. for 10 hours. The reaction solution is cooled and then filtered. 40 parts by mass of methanol is added to the filtrate and stirred at 5 ° C. or lower for 1 hour. The produced crystals are filtered, washed with methanol and dried. After adding 1.0 part by mass of crystals to 14 parts by mass of N, N-dimethylformamide and dissolving at 60 ° C., an oxidizing agent corresponding to X ⁻ (for example, in the case of silver tris (trifluoromethanesulfonyl) methidoate, 0.91 parts by mass) is added to 14 parts by mass of N, N-dimethylformamide, and the mixture is allowed to react for 30 minutes. After cooling, the precipitated silver is filtered, and 20 parts by mass of water is slowly added dropwise to the filtrate, followed by stirring for 15 minutes. The produced crystals are filtered, washed with 50 parts by mass of water, and dried to obtain compound (1).

  Examples of the resin include a transparent resin or an adhesive that can transmit visible light. The glass transition temperature (Tg) of the resin is preferably 200 ° C or lower, more preferably 150 ° C or lower, and particularly preferably 80 ° C or lower. When a resin having a low Tg is used, the characteristics of the compound (1) (excellent moisture resistance) are conspicuous as compared with conventional diimonium dyes. Therefore, the optical film of the present invention is suitable as an optical film using a resin having a low Tg. In particular, the characteristics of the present invention are exhibited in an optical film in which a diimonium dye is blended with a pressure-sensitive adhesive (Tg is usually 0 ° C. or lower) which is a resin having a low Tg. The glass transition temperature (Tg) is a temperature obtained from differential scanning calorimetry (JIS K-7121).

Examples of the transparent resin include thermoplastic resins such as polyester resins, polyolefin resins, polycycloolefin resins, polycarbonate resins, and polyacryl resins. Commercially available products of transparent resins include polyester resins such as Kanebo, trade name “O-PET”; polyolefin resins such as JSR, trade name “ARTON”; trade name “ZEONEX”, manufactured by Nippon Zeon. Polycycloolefin resins such as Mitsubishi Engineering Plastics, polycarbonate resin such as “Iupilon”, and polyacrylic resins such as Nippon Shokubai Co., Ltd., product name “Harus Hybrid IR-G204”.
Examples of the adhesive include acrylic adhesives, silicone adhesives, urethane adhesives, and butadiene adhesives.

The near-infrared absorbing layer is a near-infrared absorbing dye other than the compound (1) (hereinafter referred to as other near-infrared absorption) having a maximum absorption wavelength (λ _max ) in the range of 800 to 1100 nm without impairing the effects of the present invention. May be included).
Examples of other near-infrared absorbing pigments include inorganic pigments, organic pigments, and organic dyes.

Inorganic pigments include cobalt dyes, iron dyes, chromium dyes, titanium dyes, vanadium dyes, zirconium dyes, molybdenum dyes, ruthenium dyes, platinum dyes, ITO dyes, ATO dyes, etc. Is mentioned.
Examples of organic pigments and organic dyes include diimonium dyes other than compound (1), anthraquinone dyes, aminium dyes, cyanine dyes, merocyanine dyes, croconium dyes, squalium dyes, azurenium dyes, and polymethines. Dyes, naphthoquinone dyes, pyrylium dyes, phthalocyanine dyes, naphthalocyanine dyes, naphtholactam dyes, azo dyes, condensed azo dyes, indigo dyes, perinone dyes, perylene dyes, dioxazine dyes, quinacridones Dyes, isoindolinone dyes, quinophthalone dyes, pyrrole dyes, thioindigo dyes, metal complex dyes, dithiol metal complex dyes, indolephenol dyes, triallylmethane dyes, and the like.

Another near-infrared absorbing dye is a dye having a maximum absorption wavelength (λ _max ) in the range of 800 to 1100 nm, and a dye having a maximum absorption wavelength (λ _max ) in the range of 800 to 900 nm is particularly preferable. When the dye is blended, the maximum absorption wavelength (λ _max ) of the compound (1) is in the vicinity of 1100 nm, so that it is possible to efficiently absorb a wide range of near infrared rays, and the total amount of the dye (compound (1) and other near-infrared rays) can be absorbed. (Total amount of infrared absorbing dye) can be reduced. Therefore, there are advantages that the cost can be reduced, the deterioration of the dye is less likely to occur, and the dye can be sufficiently dissolved in the organic solvent when forming the near infrared absorption layer.

As other near-infrared absorbing dyes, cyanine dyes, phthalocyanine dyes, naphthalocyanine dyes, aminium dyes, metal complex dyes, pyrrole dyes, anthraquinone dyes and the like are preferable, and the maximum absorption wavelength (λ _max ) Are particularly preferred cyanine dyes or phthalocyanine dyes in the range of 800 to 900 nm. In addition, since the aminium dye is a radical scavenging compound (quencher compound), it is not a radical scavenging compound when used in combination with a dye that is not a radical scavenging compound such as compound (1) or a cyanine dye. This is effective for improving the durability of optical films using dyes. Accordingly, the other near infrared absorbing dye is preferably at least one near infrared absorbing dye selected from aminium dyes and cyanine dyes. In particular, a combination of the compound (1) and an aminium dye, or a combination of the compound (1), a cyanine dye and an aminium dye is preferable.

When combined compound (1) and a cyanine dye and aminium dyes, if the maximum absorption wavelength of the cyanine dye (lambda _max) within a range of 800 to 1100 nm, the maximum absorption wavelength of aminium dye (lambda _max) is It may not be in the range of 800 to 1100 nm.
When combining the compound (1), the cyanine dye and the aminium dye, since the aminium dye is a quencher compound, even if an ultraviolet absorber is further included in the near infrared absorption layer, it is influenced by the ultraviolet absorber. This is preferable because deterioration of the near-infrared absorbing layer such as discoloration and fading can be prevented.

  0.1-20.0 mass parts is preferable with respect to 100 mass parts of resin, and, as for the total compounding quantity of a compound (1) and another near-infrared absorption pigment | dye, 1.0-15.0 mass parts is especially. preferable. When the blending amount is 0.1 parts by mass or more, sufficient near infrared absorption ability can be obtained. When the blending amount is 20.0 parts by mass or less, the interaction between the dyes is suppressed, and the dye stability is improved.

  The amount of the other near-infrared absorbing dye is preferably 5 to 50% by weight in a total of 100% by weight of the compound (1) and the other near-infrared absorbing dye. By setting the amount of other near infrared absorbing pigments to 5% by mass or more, the total pigment amount can be sufficiently reduced. By setting the amount of the other near infrared absorbing dye to 50% by mass or less, the effect of the compound (1) is sufficient.

  Near-infrared absorbing layer is a color correction dye, leveling agent, antistatic agent, thermal stabilizer, antioxidant, dispersant, flame retardant, lubricant, plasticizer, or ultraviolet absorption that has a maximum absorption wavelength in the range of 300 to 800 nm. An agent or the like may be contained. As the ultraviolet absorber, a benzotriazole-based ultraviolet absorber is preferable.

  A near-infrared absorption layer dissolves a compound (1), resin, and another component as needed in an organic solvent, for example, applies the obtained coating liquid on a base material, and dries. Can be formed.

  Examples of the organic solvent include alcohols such as methanol, ethanol, isopropyl alcohol, diacetone alcohol, ethyl cellosolve, and methyl cellosolve; ketones such as acetone, methyl ethyl ketone, cyclopentanone, and cyclohexanone; N, N-dimethylformamide, N, N Amides such as dimethylacetamide; sulfoxides such as dimethyl sulfoxide; ethers such as tetrahydrofuran, dioxane and ethylene glycol monomethyl ether; esters such as methyl acetate, ethyl acetate and butyl acetate; chloroform, methylene chloride, dichloroethylene, Aliphatic halogenated hydrocarbons such as carbon tetrachloride and trichloroethylene; aromatics such as benzene, toluene, xylene, monochlorobenzene and dichlorobenzene; n-hexane, Black aliphatic hydrocarbons hexanoate ligroin; tetrafluoro propyl alcohol, fluorine-based solvents such as pentafluoropropyl alcohol.

  Coating liquid coating methods include dip coating, spray coating, spinner coating, bead coating, wire bar coating, blade coating, roller coating, curtain coating, slit die coater, gravure coater, A coating method such as a slit reverse coater method, a micro gravure method, or a comma coater method can be used.

  The thickness of the near infrared absorbing layer is preferably 0.3 to 50.0 μm, particularly preferably 0.5 to 20.0 μm. By setting the thickness of the near infrared absorbing layer to 0.3 μm or more, the near infrared absorbing ability can be sufficiently exhibited. By setting the thickness of the near-infrared absorbing layer to 50 μm or less, the residual organic solvent at the time of molding can be reduced.

(Base material)
When a peelable substrate is used as the substrate, an optical film consisting only of the near infrared absorbing layer is obtained by peeling off the peelable substrate.
When a transparent support film (hereinafter referred to as a support film) is used as the substrate, a film in which the support film and the near-infrared absorbing layer are integrated is obtained.

  The peelable substrate may be in the form of a film or a plate, and the material is not particularly limited. In order to improve the releasability, it is preferable to perform a mold release treatment on the surface of the substrate using silicone, a low surface tension resin, or the like.

  Examples of the material for the support film include polyesters such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT); polyolefins such as polyethylene and polypropylene; polyacrylates such as polymethyl methacrylate (PMMA): polycarbonate (PC), Examples thereof include polystyrenes, triacetates, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, ethylene-vinyl acetate copolymers, polyvinyl butyral, polyurethanes, cellophane and the like, and PET, PC, and PMMA are preferable.

The thickness of the support film is preferably 10 to 500 μm from the viewpoint of good workability and low haze value.
Before forming the near-infrared absorbing layer on the support film, the surface of the support film is preferably subjected to corona treatment or easy adhesion treatment.

(Functional layer)
The optical film of the present invention may have one or more arbitrary functional layers other than the near-infrared absorbing layer. As the functional layer, for example, an ultraviolet absorbing layer for preventing deterioration of pigment due to ultraviolet rays and improving light resistance; an antireflection layer for improving image visibility; blocking electromagnetic waves emitted from a display device such as a PDP Electromagnetic wave shielding layer for carrying out; Hard coat layer for giving scratch resistance; Self-repairing layer; Antifouling layer for preventing dirt on the outermost surface; Adhesive layer or adhesive layer for laminating each layer Can be mentioned. The near-infrared absorbing layer may have the function of the functional layer. For example, the near infrared absorbing layer may be an adhesive layer or an adhesive layer. Moreover, the near-infrared absorption layer may have an ultraviolet absorption function, an electromagnetic wave shielding function, or the like.

(Optical member)
The optical member is obtained by adhering the optical film of the present invention to a transparent substrate having high rigidity (hereinafter referred to as a transparent substrate) via an adhesive layer. The pressure-sensitive adhesive layer may be a near-infrared absorbing layer. The optical member can also function as a protective plate for a display device such as a PDP.
Examples of the material for the transparent substrate include inorganic materials such as glass, tempered or semi-tempered glass, and polymer materials such as polycarbonate and polyacrylate.

Examples of the pressure-sensitive adhesive used as other than the pressure-sensitive adhesive in the near-infrared absorbing layer include commercially available pressure-sensitive adhesives. Specific examples include acrylic ester copolymer, polyvinyl chloride, epoxy resin, polyurethane, vinyl acetate copolymer, styrene-acrylic copolymer, polyester, polyamide, polyolefin, styrene-butadiene copolymer rubber, butyl rubber, A silicone resin etc. are mentioned.
When providing the pressure-sensitive adhesive layer, it is preferable to attach a release film such as PET coated with silicone to the pressure-sensitive adhesive surface in terms of workability.
You may add the additive which has various functions, such as a ultraviolet absorber, to an adhesive layer.

The optical film or optical member of the present invention is a flat display device such as a PDP, a plasma addressed liquid crystal (PALC) display panel, a field emission display (FED) panel; an optical for a display device such as a cathode ray tube display (CRT). It can be used as a filter.
The optical filter may be installed on the viewing side of the display device. At this time, the optical filter may be installed away from the display device or may be directly attached to the display device surface.

  The optical film of the present invention has high near-infrared absorbing ability and is excellent in durability such as moisture resistance and heat resistance, and thus is suitable for an optical filter such as PDP that generates near-infrared rays.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.
Examples 1 to 8, 14, and 15 are examples, and examples 9 to 13 and 16 are comparative examples.

Λ _max and ε _m of the near-infrared absorbing dye (compound (1) and near-infrared absorbing dye) were measured by the following procedure.
The near-infrared absorbing dye was diluted with chloroform so that the sample concentration was 20 mg / L to prepare a sample solution. The absorption spectrum of this sample solution was measured in the range of 300 to 1300 nm using UV-3100 manufactured by Shimadzu Corporation, the maximum absorption wavelength (λ _max ) was read, and the molar extinction coefficient at the _maximum absorption wavelength (λ _max ). (Ε _m ) was calculated from the following equation.
ε _m = ε / (c · d).
Where ε is an extinction coefficient, calculated as ε = −log (I / I ₀ ), I ₀ is the light intensity before incidence, I is the light intensity after incidence, and ε _m is the molar extinction coefficient. Where c is the sample concentration (mol / L) and d is the cell length.

(Example 1)
A transparent acrylic resin (made by Nippon Shokubai Co., Ltd., trade name “HALS HYBRID IR-G204”: glass transition temperature 89 ° C.) is dissolved in methyl ethyl ketone (MEK) so that the resin content is 15% by mass. Obtained. 14.0 parts by mass of compound (1) (N, N, N ′, N′-tetrakis (p-diisobutylaminophenyl) -p-phenylenediamine bis (100 parts by mass) with respect to 100 parts by mass of the resin content of the main agent solution tris (trifluoromethanesulfonyl) methide acid) imonium salt, λ _max: 1108nm, adding _shrimp flavor F6.3 × 10 ⁴⁾ in the main agent solution to obtain a coating solution obtained by dissolving them. This coating solution was coated on a 100 μm-thick PET film (trade name “A4100”, manufactured by Toyobo Co., Ltd.) with a microgravure so that the thickness of the dried coating film was 4 μm, and then at 120 ° C. for 5 minutes. It was made to dry and the near infrared absorption layer was formed, and the optical film was obtained.

(Example 2)
The main agent solution of Example 1 was prepared by using a transparent polyester resin (trade name “O-PET”, manufactured by Kanebo Co., Ltd., glass transition temperature: 140 ° C.), cyclopentanone / toluene (6 / 4 volume ratio) An optical film was obtained in the same manner as in Example 1 except that the base solution was dissolved in a mixed solvent.

(Example 3)
Main agent solution prepared by dissolving transparent polycarbonate resin (manufactured by Teijin Chemicals Ltd., trade name “PC-N1”, glass transition temperature 190 ° C.) in cyclopentanone so that the resin content is 15% by mass. An optical film was obtained in the same manner as in Example 1 except that the solution was replaced.

(Example 4)
An optical film was obtained in the same manner as in Example 1 except that the transparent acrylic resin of Example 1 was replaced with a transparent acrylic resin (manufactured by Nippon Shokubai Co., Ltd., trade name “PDP108”, glass transition temperature 79 ° C.).

(Example 5)
An acrylic pressure-sensitive adhesive (manufactured by Toyo Ink Manufacturing Co., Ltd., trade name “NCK101”, glass transition temperature −26 ° C.) was dissolved in MEK so that the resin content was 15% by mass to obtain a base solution. With respect to 100 parts by mass of the resin content of the main agent solution, 2.3 parts by mass of the compound (1) of Example 1 was added to the main agent solution to obtain a coating solution in which these were dissolved. The coating solution is coated with an applicator on a PET film having a thickness of 100 μm (trade name “A4100”, manufactured by Toyobo Co., Ltd.) so that the thickness of the dried coating film becomes 25 μm, and the temperature is 120 ° C. for 5 minutes. It was made to dry and the adhesive near-infrared absorption layer was formed, and the optical film was obtained. An optical film with an antireflection function is formed by bonding the near-infrared absorbing layer of the optical film and the surface opposite to the antireflection layer of a 100 μm-thick antireflection film (trade name “Realak 7710UV” manufactured by NOF Corporation). A film was obtained.

(Example 6)
An optical film with an antireflection function was obtained in the same manner as in Example 5 except that the amount of the compound (1) in Example 5 was changed from 2.3 parts by mass to 0.9 parts by mass.

(Example 7)
A transparent acrylic resin (made by Nippon Shokubai Co., Ltd., trade name “HALS HYBRID IR-G207”, glass transition temperature: 76 ° C.) is dissolved in methyl ethyl ketone (MEK) so that the resin content is 15% by mass. Obtained. With respect to 100 parts by mass of the resin content of the main agent solution, 25.0 parts by mass of the compound (1) of Example 1 was added to the main agent solution to obtain a coating solution in which these were dissolved. The coating solution is coated on a 100 μm-thick PET film (trade name “A4100”, manufactured by Toyobo Co., Ltd.) with a micro gravure so that the thickness of the dried coating film is 4 μm, and then at 120 ° C. for 5 minutes. It was made to dry and the near-infrared absorption layer was formed, and the optical film was obtained.

(Example 8)
2100 parts by weight of the compound (1) of Example 1 and 2.6 parts by weight of a stabilized cyanine dye (manufactured by Sumitomo Seika Co., Ltd., trade name “ SD-AG01 ", λ _max = 877 nm, ε _m = 3.1 × 10 ⁵ ), and 2.6 parts by mass of trifluoromethanesulfonylmethideic acid / cyanine dye (manufactured by Nippon Kayaku Co., Ltd., trade name“ CY- ”) 40MCM ”, λ _max = 820 nm, ε _m = 2.7 × 10 ⁵ ), and further 1.3 parts by mass of N, N, N ′, N′-tetrakis (p-diisobutylaminophenyl) -p-phenylenediamine An optical film was obtained in the same manner as in Example 7 except that -bis (bis (trifluoromethanesulfonyl) imidic acid) aminium salt was added.

(Example 9)
Instead of the compound (1) of Example 7, (N, N, N ′, N′-tetrakis (p-diisobutylaminophenyl) -p-phenylenediamine bis (bis (trifluoromethanesulfonyl) imidic acid) imonium salt is used. An optical film is obtained in the same manner as in Example 7 except that it is used.

(Example 10)
Instead of the compound (1) of Example 6, (N, N, N ′, N′-tetrakis (p-diisobutylaminophenyl) -p-phenylenediamine bis (bis (trifluoromethanesulfonyl) imidic acid) imonium salt is used. An optical film is obtained in the same manner as in Example 6 except that it is used.

(Example 11)
In place of the compound (1) of Example 4, a diimonium dye (N, N, N ′, N′-tetrakis (p-dinormalbutylaminophenyl) -p-phenylenediamine · bis (tris (trifluoromethanesulfonyl)) An optical film was obtained in the same manner as in Example 4 except that (methidic acid) imonium salt (λ _max = 1105 nm, ε _m = 6.3 × 10 ⁴ ) was used.

(Example 12)
Instead of the diimonium dye of Example 11, the diimonium dye (λ _max = 1067 nm, ε _m = 6.3 × 10 ⁴ ) in which the side chain R of the diimonium dye of Example 11 was replaced with cyanopropyl was used. In the same manner as in Example 11, an optical film was obtained.

(Example 13)
The compound (1) of Example 4 was converted into a diimonium dye (N, N, N ′, N′-tetrakis (p-dinnormalbutylaminophenyl) -p-phenylenediamine · bis (bis (trifluoromethanesulfonyl) imidic acid). ) Immonium salt, λ _max = 1100 nm, ε _m = 7.3 × 10 ⁴ ), except that the optical film was obtained in the same manner as in Example 4.

(Example 14)
To the main agent solution of Example 8, 86.8 parts by mass of a benzotriazole-based ultraviolet absorber (manufactured by Ciba Specialty Chemicals, trade name “Tinuvin 928”) was further added to 100 parts by mass of the resin content of the main agent solution. Except for the above, an optical film was obtained in the same manner as in Example 8.

(Example 15)
In Example 14, except that N, N, N ′, N′-tetrakis (p-diisobutylaminophenyl) -p-phenylenediamine-bis (bis (trifluoromethanesulfonyl) imidic acid) aminium salt was not added. In the same manner as in Example 14, an optical film was obtained.

(Example 16)
A diimonium dye (λ _max = 1067 nm, ε _m = 6.3 × 10 ⁴ ) in which the side chain R of the diimonium dye of Example 7 was replaced with cyanopropyl was used in place of the diimonium dye of Example 7. In the same manner as in Example 7, an optical film was obtained.

The optical properties (luminous average transmittance, chromaticity, near infrared transmittance) and durability (heat resistance, moisture resistance) of the optical films of Examples 1 to 16 were evaluated by the following methods. The results are shown in Table 1.
Table 1 also shows anions of compounds (1) of Examples 1 to 16 or other diimonium dyes, side chains R (corresponding to R ^{1 to} R ⁸ in the cation of formula (1)), and resin glass. The transition temperature (Tg) is also shown.

(optical properties)
Using a spectrophotometer (manufactured by Shimadzu Corporation, UV-3100), the spectrum of a 20 × 20 mm square test piece cut out from each sample was measured in the range of 380 to 1300 nm. According to JIS Z 8701-1999, the weighted average transmittance (luminous average transmittance Tv) and chromaticity coordinates (x, y) in the visible region (380 to 780 nm) were calculated.
Further, the transmittance in the near-infrared region (850 nm, 900 nm, 950 nm, 1000 nm) was measured, and the near-infrared transmittance was determined using the indoor air transmittance as a comparative control. The near-infrared transmittance at each wavelength was T850, T900, T950, and T1000, respectively.

(Heat-resistant)
Using a constant temperature thermostat (manufactured by Tokyo Rika Kikai Co., Ltd.), the temperature was set to 80 ° C., and the measured values of Tv, x, y of each sample after the 500 hour test were compared with the measured values before the test. Yes, if the amount of change before and after the test is less than 3%, △ if any one is 3% to less than 5%, △, if any one is more than 5% X.

(Moisture resistance)
Using a constant temperature and humidity tester (manufactured by Tokyo Rika Kikai Co., Ltd., KCH-1000), the temperature is set to 60 ° C. and the humidity is 95% RH, and the measured values of Tv, x, y of each sample after 500 hours test are as follows: The measured values were compared with those before the test. Yes, if the amount of change before and after the test is less than 3%, △ if any one is 3% to less than 5%, △, if any one is more than 5% X.

(Light resistance)
Using a light resistance tester (Suga Test Instruments Co., Ltd., Xenon Fade Meter X-15F), irradiating light of 380 nm or more with 200 MJ / cm ² (132 hours), and measuring each value of Tv, x, y of each sample Compared with the measured value before the test. Yes, if the amount of change before and after the test is less than 3%, △ if any one is 3% to less than 5%, △, if any one is more than 5% X.

As shown in Table 1, the optical films (Examples) of Examples 1 to 8, 14, and 15 were good in both heat resistance and moisture resistance. In particular, the optical films of Examples 7 and 8 in which a dye other than the diimonium dye was also blended exhibited excellent optical properties despite the small amount of the total dye.
On the other hand, the optical films of Examples 11 and 13 using normal butyl as the side chain R and Examples 12 and 16 using cyanopropyl had poor moisture resistance, and in particular, Examples 12 and 16 had poor heat resistance.

The optical film of the present invention is useful as an optical filter for various display devices, and is particularly suitable for an optical filter that is installed and used on the viewing side of a PDP.

Claims (5)

An optical film having a near-infrared absorbing layer containing a compound represented by the following formula (1) and a resin.

^However, R 1 to R ⁸ is an isobutyl, X ^{- _{is, (R f SO 2) 3}} C - represents an anion represented by the ^{R f,} represents a fluoroalkyl group having 1 to 4 carbon atoms .   The optical film according to claim 1, wherein the fluoroalkyl group is a perfluoroalkyl group. The near-infrared absorbing layer further contains a near-infrared absorbing dye other than the compound represented by the formula (1), wherein the maximum absorption wavelength (λ _max ) is in the range of 800 to 1100 nm. The optical film described in 1.   The optical film according to claim 3, wherein the near-infrared absorbing dye other than the compound represented by the formula (1) is at least one near-infrared absorbing dye selected from an aminium dye and a cyanine dye. The optical film in any one of Claims 1-4 whose glass transition temperature (Tg) of the said resin is 80 degrees C or less.