Infrared absorption filter

Infrared absorption filter

[Technical Field]

The present invention relates to an infrared absorption filter. In detail, the infrared absorption filter of the present invention relates to an infrared absorption filter that rarely causes optical defects, has high transmittance in the visible light range, and broadly absorbs and blocks infrared in the near infrared range.

[Prior Art]

In the past, infrared absorption filters such as heat-ray absorption filters and video-recorder visual sensitivity correction filters are widely used as shown below.

(1) Filters containing metal ions such as copper or iron in phosphoric acid-based glass (Japanese Patent Application Publication No. 60-235740, Japanese Patent Application Publication No. 62-153144, etc.)

(2) An interference filter in which layers with different refractive indexes are laminated on a substrate, and the transmitted light is interfered to transmit a specific wavelength (Japanese Patent Application Publication No. 55-21091, Japanese Patent Application Publication No. 184745, etc.)

(3) Acrylic resin filter containing copper ions in the copolymer (Japanese Patent Laid-Open No. 6-324213)

(4) A filter composed of dispersing pigment in a binder resin (Japanese Patent Application Publication No. 57-21458, Japanese Patent Application Publication No. 57-198413, Japanese Patent Application Publication No. 60-43605, etc.)

In addition, various transparent electromagnetic wave absorbing materials have been reviewed, for example, the following materials. In addition, there are also many proposals that combine these.

(5) Electromagnetic wave protection material using conductive fiber fabric

(6) Etching thin metal plates to make electromagnetic wave protection materials for screens

(7) Make high-conductivity metals such as silver, or ITO or SnO₂Transparent conductive materials such as electromagnetic wave protection materials that are thinned by sputtering or vacuum evaporation

However, such conventionally used infrared absorption filters have various problems as shown below.

In the case of the above method (1), it has extremely narrow absorption in the near infrared range and excellent infrared blocking rate, but part of the visible light range has a large red absorption, and the transmission color can be seen as blue. In display applications, it is not suitable for this purpose due to the importance of color balance. Moreover, there are also problems with workability when it is made of glass.

In the above method (2), optical characteristics can be freely designed, and a filter approximately equivalent to the design can be manufactured. Therefore, it is necessary to have a large number of laminated layers with refractive index difference, which has disadvantages such as high manufacturing cost. In addition, when a large area is required, high-precision film thickness uniformity across the entire area is required, which makes it difficult to manufacture.

In the case of the above method (3), the disadvantage of the above method (1) can be improved. However, the degree of freedom in designing optical characteristics is low in the same manner as in the above-mentioned (1). In addition, absorption in the red part of the visible light range and blue in the filter is an unchangeable problem in (1) above. In addition, since the absorption of copper ions is small and the amount of copper ions that can be contained in the acrylic resin is limited, there is a problem that the acrylic resin must be thickened.

In the case of the above method (4), the infrared absorbing pigments are used: cyanines, nickel complexes, diiminium salts, azo compounds, polymethines, diphenylmethanes, triphenyls Many pigments such as methane series and series. However, each has problems such as insufficient absorption alone and absorption of a specific wavelength in the visible light range. Therefore, several pigments can be used in combination. However, after a filter containing several pigments in the infrared absorption layer is left under high temperature and high humidity for a long time, it will become pigment due to the decomposition or oxidation of the pigment, which absorbs in the visible light range and does not absorb in the infrared range. problem. Moreover, when these filters are of the type with an infrared absorbing layer coated on a base film, the transmittance or haze value of the base film causes poor light transmission characteristics.

In addition, when the infrared absorption filter of the aspect (1) to (4) above is combined with the electromagnetic wave absorbing material described in (5) to (7) above, the above problem cannot be improved.

In recent years, PDPs have been developed as thin and large-screen displays. Near infrared rays emitted from the front may cause malfunctions of remote controllers, etc., and an infrared absorption filter that cuts off the near infrared rays must be installed in the front. However, the current infrared cut filter for PDP and the infrared absorption filters (1) to (4) above still cannot fully meet the requirements.

In the above-mentioned method (4), when a diiminium salt-based compound is used as an infrared-absorbing dye, the above-mentioned problems can be overcome, and a filter that satisfies high absorption in the near-infrared range and requires low absorption in the visible light range can be obtained. In addition, it can also be used as an infrared absorption filter for PDP.

However, when foreign matter exists in the raw material resin of the base film of the infrared absorption filter, the molecular alignment of the film may be disordered around the foreign matter during the stretching step during film formation. As a result, defects such as optical skew and much larger foreign objects than actual foreign objects occur, which will significantly degrade the quality. For example, a foreign object with a size of 20 μm is regarded as 50 μm in ordinary optics, and a foreign object with a size of 100 μm or more is regarded as an optical defect. In order to make a highly transparent film, it is better to not contain particles to impart slippery properties in the base film, or to make the particle content as small as possible. However, the smaller the particle content, the higher the transparency of the film, due to the small foreign matter. The tendency to make optical defects more pronounced. In addition, the thickness of the base film of the infrared absorption filter is generally 50 μm or more, and the thickness of the film per unit area in the thickness direction of the film has a relatively small foreign matter content, which is a major problem.

In addition, in order to make the base film easy to slip, when the base film does not contain particles or the content of particles is reduced within a range that does not impair transparency, it is generally necessary to contain it to make the easy-adhesive layer easy For the purpose of slippery particles, these particles must be used with extremely small particle diameters within the range that does not impair transparency. However, fine particles with a small particle size are extremely easy to aggregate and may become coarse aggregates. When the easy-adhesive layer containing the coarse aggregate is laminated on the base film, the coarse aggregate becomes an optical defect.

[Revelation of Invention]

The first object of the present invention is to provide an infrared absorption filter that absorbs in the near-infrared range, has high transmittance in the visible light range, has little absorption of specific wavelengths in the visible light range, and has fewer optical defects.

Furthermore, the object of the present invention is to provide an infrared absorption filter excellent in environmental stability or durability.

In addition, the second object of the present invention is to provide the infrared absorption filter with a blue-gray hue.

The present invention is an infrared absorption filter that can solve the above-mentioned problems in view of the above-mentioned situation, as described below.

The first invention of the present invention is an infrared absorbing filter, which is an infrared absorbing filter formed by laminating an infrared absorbing layer on at least one side of a transparent polymer film, characterized by laminating an infrared absorbing layer on at least one side of the transparent polymer film The infrared absorbing layer is substantially free of particles in the transparent polymer film, and there are 10 foreign substances with a size of 20 μm in the unit area of the film in the transparent polymer film.

The second invention is an infrared absorption filter as in the first invention, wherein the infrared absorption filter has a maximum transmittance of 30% or less in the near-infrared range with a wavelength of 800 nm to 1100 nm, and a visible light range with a wavelength of 450 nm to 650 nm. The difference between the maximum and minimum transmittance is 10% or less, and the transmittance at a wavelength of 550 nm is 50% or more.

The third invention is the infrared absorption filter of the first or second invention, wherein the infrared absorption filter is placed in an atmosphere at a temperature of 60°C and a humidity of 95% for 500 hours, and the maximum transmittance in the near-infrared range with a wavelength of 800 nm to 1100 nm It is 30% or less, and the difference between the maximum and minimum transmittance of the visible light range of wavelength 450nm~650nm is 10% or less, and the transmittance of wavelength 550nm is 50% or more.

The fourth invention is an infrared absorption filter as in the first invention, wherein the infrared absorption filter has a maximum transmittance of 10% or less in the near-infrared range with a wavelength of 900nm~1100nm, and a visible wavelength of 440nm~500nm and 640nm~700nm. The minimum transmittance in the light range is 60% or more, the maximum transmittance in the visible light range with a wavelength of 550 to 600 is 60% or less, and the transmittance at a wavelength of 550 nm is 50% or more.

The fifth invention is an infrared absorbing filter according to any one of the first to fourth inventions, wherein the infrared absorbing layer is mainly composed of infrared absorbing dyes and polymer resins, and contains at least two diimonium salt compounds, The group of cyanines and nickel complex compounds are used as infrared absorbing dyes.

The sixth invention is the infrared absorption filter according to the fifth invention, wherein the infrared absorption pigment contains a diimonium salt-based compound and at least one fluorine-containing cyanine-based compound and a nickel complex-based compound.

The seventh invention is the infrared absorption filter according to the fifth or sixth invention, wherein the diimonium salt compound has a structure represented by general formula (1).

<img file="TW472158B_D0001.tif" />

(Where R₁~R₈Represents a hydrogen atom, an alkyl group, an aryl group, an alkenyl group, an aralkyl group or a fast group, which may be the same or different; R₉~R₁₂System represents a hydrogen atom, a halogen atom, an amino group, an amide group, a cyano group, a nitro group, a carboxylic acid group, each of which may be the same or different; R₁~R₁₂Those that may be bonded to a substituent may also have a substituent; the X system represents an anion).

The eighth invention is the infrared absorption filter according to the fifth, sixth or seventh invention, wherein the cyanine-based compound is a fluorine-containing cyanine-based compound.

The ninth invention is an infrared absorption filter according to any one of the fifth to eighth inventions, wherein the nickel complex compound has a structure shown in general formula (2).

<img file="TW472158B_D0002.tif" />

(Where R₁₃~R₁₆System represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group, or an amino group, which may be the same or different)

The tenth invention is an infrared absorbing filter according to any one of the fifth to ninth inventions, wherein the infrared absorbing layer contains an infrared absorbing dye in a mixing ratio of 1.2 to 0.01 for 1 part by weight of the diimonium salt compound Parts by weight: cyanine-based compound, 1 to 0 parts by weight of nickel complex-based compound.

The eleventh invention is the infrared absorption filter according to any one of the fifth to tenth inventions, wherein the glass transition temperature of the polymer resin constituting the infrared absorption layer is 85 to 150°C.

The twelfth invention is an infrared absorption filter according to any one of the fifth to eleventh inventions, wherein the polymer resin contains polyester as a main component.

The 13th invention is the infrared absorption filter according to the 12th invention, wherein the polyester resin is a copolymerized polyester containing 60 mol% or more of the alicyclic diol represented by the general formula (3) as the polyol component Resin.

<img file="TW472158B_D0003.tif" />

(Where R₁₇And R₁₈It means that the hydroxyl group and/or the hydroxyalkylene group with 1 to 8 carbons and/or the hydroxyalkylene group with 1 to 4 carbons are added with 1-10 alkylene oxides)

The fourteenth invention is the infrared absorption filter of any one of the first to thirteenth inventions, wherein the amount of residual solvent in the infrared absorption layer is 0.05 to 5% by weight.

The fifteenth invention is the infrared absorption filter according to any one of the first to fourteenth inventions, wherein the infrared absorption layer is laminated on the transparent polymer film by a coating method.

The sixteenth invention is the infrared absorption filter according to any one of the first to fifteenth inventions, wherein the transparent polymer film is a biaxially stretched polyester film.

The seventeenth invention is the infrared absorption filter according to any one of the first to sixteenth inventions, wherein the polymer easy-adhesive layer contains a copolymerized polyester resin and a polyurethane resin.

The eighteenth invention is an infrared absorption filter according to any one of the first to seventeenth inventions, in which a coarse object having a maximum diameter of 10μm exists on the surface and/or inside of the polymer easy-adhesive layer, and is present in the polymer easy-adhesive layer The unit area is 3 pieces/m²the following.

The nineteenth invention is the infrared absorption filter according to any one of the first to eighteenth inventions, wherein particles are contained in the polymer easily-adhesive layer.

The 20th invention is the infrared absorption filter according to any one of the 1st to 19th inventions, wherein the haze value of the transparent polymer film is 1% or less.

The 21st invention is the infrared absorption filter according to any one of the 1st to 20th inventions, wherein an antireflection layer is laminated on the outermost layer of the infrared absorption filter.

The 22nd invention is an infrared absorption filter according to any one of the first to 20th inventions, wherein an anti-glare treatment layer is laminated on the outermost layer of the infrared absorption filter.

The 23rd invention is an infrared absorption filter according to any one of the 1st to 22nd inventions, which is used as a front panel member of a plasma display.

[Implementation of the invention]

The infrared absorption filter of the present invention is characterized in that a transparent polymer film is used as a base material, and an infrared absorption layer is laminated on at least one side of the base material, and a polymer easy-adhesive layer is laminated on at least one side of the transparent polymer film. constitute.

(The composition of the infrared absorption layer)

In the infrared absorption filter of the present invention, the infrared absorption layer is mainly composed of an infrared absorption dye and a polymer resin. In the present invention, in terms of productivity, processability, and cost, it is preferable to disperse the infrared-absorbing dye in a polymer resin and coat it on at least one side of a transparent polymer film. At this time, in order to improve the adhesion between the transparent polymer film of the substrate and the infrared absorbing layer, it is preferable to have a polymer easy-adhesion layer between the transparent polymer film and the infrared absorbing layer.

In the present invention, the infrared-absorbing dye system contained in the infrared-absorbing layer is preferably used in combination with at least two types selected from the group consisting of diimonium salt-based compounds, cyanine-based compounds, and nickel complex-based compounds. Furthermore, the infrared absorbing dye contained in the infrared absorbing layer particularly preferably contains at least a diimonium salt-based compound, and at least one cyanine-based compound and a nickel complex-based compound. The cyanine-based compound and/or the nickel-sulfur-based complex compound used in the present invention is better to correct the absorption in the near-infrared range of the diimonium salt compound. In addition, the mixing ratio of the red-line absorbing pigment is 1.2 to 0.01 parts by weight (preferably 0.5 to 0.01 parts by weight) of the cyanine compound for 1 part by weight of the diimonium salt compound, and nickel complex The compound is 1 to 0 parts by weight to produce (1) absorption in the near-infrared range, (2) high light transmission in the visible light range, and (3) little absorption of specific wavelengths in the visible light range The infrared absorption filter is suitable.

The infrared absorbing dye is, for example, as shown below. The diimonium salt compound is not particularly limited as long as it has a large absorption in the near infrared range and a high visible light transmittance, but it is preferably a structural formula represented by general formula (1).

<img file="TW472158B_D0004.tif" />

(Where R₁~R₈Represents a hydrogen atom, an alkyl group, an aryl group, an alkenyl group, an aralkyl group or an alkynyl group, each of which may be the same or different; R₉~R₁₂System represents a hydrogen atom, a halogen atom, an amino group, a amide group, a cyano group, a nitro group, a carboxylic acid group, each of which may be the same or different; may be R₁~R₁₂The bonding substituent may also have a substituent; X represents an anion)

R of the above general formula (1)₁~R₈In the alkyl group, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, 3-butyl, n-pentyl, n-hexyl, n-octyl, 2-hydroxyethyl , 2-cyanoethyl, 3-hydroxypropyl, 3-cyanopropyl, methoxyethyl, ethoxyethyl, butoxyethyl, etc. In addition, aryl groups include, for example, phenyl, fluorinated phenyl, chlorinated phenyl, tolyl, diethylaminophenyl, yl, etc., and alkenyl includes vinyl, propenyl, butenyl, and pentene. Base etc. In addition, the aralkyl group includes, for example, a benzyl group, a p-fluorinated benzyl group, a p-chlorophenyl group, a phenylpropyl group, and a ylethyl group.

Moreover, R in general formula (1)₉~R₁₂For example, hydrogen, fluorine, chlorine, bromine, diethylamino, dimethylamino, cyano, nitro, methyl, ethyl, trifluoromethyl and the like. X includes, for example, fluoride ion, chloride ion, bromide ion, iodide ion, perchlorate ion, hexafluoroantimonate ion, hexafluorophosphate ion, and tetrafluoroborate ion. However, the present invention is not limited by the above exemplified ones.

Commercially available products of the diimonium salt-based compound include, for example, Kayasorb IRG-022, URG-023 manufactured by Nippon Kayaku Co., Ltd. and the like.

The cyanine compound is preferably a fluorine-containing cyanine compound.

The commercially available cyanine compounds include Excolor IR1, IR2, IR3, IR4, TX-EX805K, TX-EX810K, TX-EX811K, TX-EX812K, etc. manufactured by Nippon Shokubai Co., Ltd. Among them, IRl and TX-EX811K are better.

The sulfur-nickel complex compound is preferably the structural formula shown in general formula (2).

<img file="TW472158B_D0005.tif" />

(Where R₁₃~R₁₆System represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group, or an amino group, which may be the same or different)

Commercially available nickel complex compounds are, for example, SIR-128, SIR-130, SIR-132, SIR-159 manufactured by Mitsui Chemicals Co., Ltd., and among them, SIR-128 and SIR-159 are more preferable.

In addition, as the constituent component of the infrared absorption layer, a polymer resin is preferably used when the infrared absorption dye is dispersed. The type of polymer resin is not particularly limited. For example, there are polyester, acrylic, cellulose, polyethylene, polypropylene, polyolefin, polyvinyl chloride, polycarbonate, phenol, and amino groups. For the formate-based resins, polyester-based resins are particularly preferred in terms of dispersion stability and environmental load.

The glass transition temperature of the polymer resin (especially polyester resin) of the dispersant of infrared absorbing pigment is better than the guaranteed temperature in the environment where the infrared absorbing filter is used to improve the weather resistance in terms of pigment stability. . The set guarantee temperature of electronic equipment is generally 80°C, so the glass transition temperature of the polymer resin is preferably above 80°C, more preferably 85~150°C. In addition, 85~130°C, 90~110°C is preferred.

When the glass transition temperature is less than 85°C, the diimonium salt compound is modified as described above. If the glass transition temperature is greater than 130°C, the polymer resin must be high temperature when it is dissolved in a solvent and fully dried when it is coated on a transparent substrate, resulting in the modification of the diimonium salt compound. In addition, other infrared absorbing dyes with weak heat resistance are deteriorated. Moreover, the drying time is long when drying at low temperature, so the productivity is not good, and it is impossible to make a low-cost infrared absorption filter. In addition, it could not be dried sufficiently.

When the glass transition temperature is within this range, it is possible to balance coating suitability and durability when the infrared absorbing layer is laminated on the transparent polymer film of the substrate by the coating method. The durability referred to here means that after a long period of storage under high temperature and high humidity, for example, in an atmosphere with a temperature of 60°C and a humidity of 95%, the spectroscopic characteristics deteriorate after the sample is left for 500 hours. In addition, it has the advantage of dispersing the infrared-absorbing dye in the polymer resin at a high concentration.

The preferred polyester resin used as the polymer resin is synthesized from a polycarboxylic acid component and a polyol component.

The polycarboxylic acid components constituting the polyester resin are, for example, p-acid, iso-acid, ortho-acid, 1,5-dicarboxylic acid, 2,6-dicarboxylic acid, bifenic acid, sulfo-p-acid , 5-sulfoiso acid, 4-sulfo acid, 4-sulfo-2,7-dicarboxylic acid, 5[4-sulfophenoxy]iso acid, sulfopara acid, etc. Aromatic dicarboxylic acids and their ester-forming derivatives; para-oxybenzoic acid, p-(hydroxyethoxy)benzoic acid and other aromatic oxycarboxylic acids and their ester-forming derivatives; succinic acid, adipic acid , Azelaic acid, sebacic acid, dodecane dicarboxylic acid, and other aliphatic dicarboxylic acids and their ester-forming derivatives; fumaric acid, maleic acid, itaconic acid, hexahydro acid, tetrahydro Unsaturated aliphatic dicarboxylic acids such as acids and their ester-forming derivatives; alicyclic dicarboxylic acids and their ester-forming derivatives, etc. Furthermore, for example, there are trivalent or higher polycarboxylic acids such as trimellitic acid, trimesic acid, and pyromellitic acid.

The polyol components constituting the polyester resin include, for example, aliphatic polyols, alicyclic polyols, and aromatic polyols.

Aliphatic polyols include, for example, ethylene glycol, propylene glycol, 1,3-propanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol , Neopentyl alcohol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol and other aliphatic glycols , Trimethylolethane, trimethylolpropane, glycerol, pentaerythritol and other triols and tetraols.

Alicyclic polyols such as 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, spiroglycol, hydrogenated bisphenol A, hydrogenated bisphenol A, etc. for ethylene oxide addition Or propylene oxide adduct, tricyclodecanediol, tricyclodecane dimethanol, tricyclodecane diethanol, dimethyl tricyclodecane dipropanol, tricyclodecane dibutanol, diethyl Base tricyclodecane dimethanol, tetramethyl tricyclodecane dimethanol, hexamethyl tricyclodecane dimethanol, octamethyl tricyclodecane dimethanol, etc.

Aromatic polyols include, for example, 9,9-bis[4-(2-hydroxyethoxy)phenyl]-, 9,9-bis[4-(2-hydroxyethoxy)3-methylbenzene Base]-Oh,9,9-bis[4-(2-hydroxyethoxy)-3,5-dimethylphenyl]-Oh,9,9-bis[4-(2-hydroxyethoxy) )-3-ethylphenyl]-, 9,9-bis[4-(2-hydroxyethoxy)-3,5-diethylphenyl]-, 1,l-bis[4- (2-Hydroxyethoxy)phenyl)-cyclohexane, 1,1-bis[4-(2-hydroxyethoxy)-3-methylphenyl]-cyclohexane, 1,1-bis [4-(2-hydroxyethoxy)-3,5-dimethylphenyl]-cyclohexane, 1,1-bis[4-(2-hydroxyethoxy)-3-ethylphenyl ]-Cyclohexane, 1,1-Bis[4-(2-hydroxyethoxy)-3,5-diethylphenyl]-cyclohexane, p-xylene glycol, xylene ethylenedi Ethylene oxide adducts or propylene oxide adducts such as alcohol, o-xylene glycol, and 1,4-benzenediol.

In addition, the polyester polyol includes, for example, lactone-based polyester polyols obtained by ring-opening polymerization of lactones such as ε-caprolactone.

Moreover, the polyol system makes the general formula (3)

<img file="TW472158B_D0006.tif" />

(Where R₁₇And R₁₈It is a hydroxy group and/or a hydroxyalkylene group with a carbon number of 1 to 8 and/or a hydroxyalkylene group with a carbon number of 1 to 4 plus 1-10 alkylene oxides). It is preferable that the component is copolymerized in a polyester resin of 60 mol% or more as a polyol component.

The alicyclic diols represented by general formula (3) are, for example, tricyclodecane dimethylol, tricyclodecane dihydroxyethyl, tricyclodecane dihydroxypropyl, tricyclodecane dibutanol, Dimethyl tricyclodecane dimethylol and so on. Where R₁₇And R₁₈Tricyclodecane dimethylol which is also a hydroxymethyl group is more preferable.

When a filter using a diimonium compound is left for a long time at a high temperature or under humidification, the absorption becomes small, showing a specific absorption in the visible light range, and changing to yellow-green. This countermeasure system proposes to use a polyester resin that appropriately increases the glass transition temperature. For example, Japanese Patent Application Publication No. 9-838855 and Japanese Patent Application Publication No. 11-116826 disclose that an infrared absorbing dye is mixed with a polyester resin copolymerized with a specific aromatic diol of 10 mol% or more. However, in the composition range where the aromatic diol is used, the glass transition temperature is too high, so that the copolymerized polyester resin and the infrared absorbing pigment are mixed with the solvent. Insufficient residual solvent leads to deterioration of environmental stability, and problems such as curling of the film after coating and drying. In addition, the solubility of the copolymerized polyester resin to the solvent is reduced, and it is not suitable for coating.

The present invention has discovered that by copolymerizing an alicyclic diol represented by the general formula (3) at 60 mol% or more in a polyester resin, it is extremely excellent in terms of solvent solubility and coatability.

If the alicyclic diol is less than 60 mol%, the solvent solubility is improved and coating is easy, but the glass transition temperature of the copolymerized polyester resin is lowered, and the environmental stability when the infrared absorbing pigment is mixed is lowered. The upper limit of the copolymerization amount of the alicyclic diol component represented by general formula (3) is preferably 95 mol% or less. When it is 95 mol% or more, the degree of polymerization of the copolymerized polyester resin is not easy to increase, and as a result, it becomes extremely brittle and undesirable.

In addition to these, polyester resins are designed to allow the polar groups at the ends of polyester polymers to seal chains and introduce monofunctional monomers into the polyester.

Monofunctional monomers can use benzoic acid, chlorinated benzoic acid, brominated benzoic acid, halogenated hydroxybenzoic acid, sulfobenzoic acid monoammonium salt, sulfobenzoic acid monosodium salt, cyclohexylaminoammonium salt, n-ten Dialkylaminocarbyl benzoic acid, 3-butyl benzoic acid, dicarboxylic acid, 4-methyl benzoic acid, 3-methyl benzoic acid, salicylic acid, thiosalicylic acid, phenyl acetic acid , Acetic acid, propionic acid, butyric acid, isobutyric acid, octane carboxylic acid, lauric acid, stearic acid, and these lower alkyl esters, and other monocarboxylic acids, or aliphatic alcohols, aromatic alcohols, alicyclic Monoalcohol such as alcohol.

In the present invention, these unsaturated monomers are essential components, and other components are appropriately selected depending on the glass transition temperature of the polyester resin, the compatibility with the monomer, and the like.

In the infrared absorption filter of the present invention, the amount of residual solvent in the infrared absorption layer is preferably 5% by weight or less. When the infrared absorbing layer is formed by a solvent-based coating method, when the residual solvent amount is greater than 5 wt%, it may dry, crack, and the glass transition temperature is significantly lowered when visually observed. In particular, when a diimonium salt compound is used as an infrared absorbing pigment, the diimonium salt compound may be denatured and the filter may turn yellow-green when it is left for a long time under high temperature and humidification.

In the present invention, the amount of residual solvent in the infrared absorption layer is more preferably 0.05 to 3% by weight. If the amount of residual solvent is less than 0.05% by weight, the infrared absorbing pigment will be less denatured when left under high temperature and high humidity for a long time, but if it is less than 0.05% by weight, the infrared absorbing pigment will easily be denatured due to the necessary heat.

In order to make the residual solvent amount of the infrared absorbing layer 5% by weight, the drying conditions satisfying the following formulas (4) to (6) can be performed at the same time. The factor units used in the following equations (4) to (6) are wind speed in m/min, hot air temperature in °C, drying time in minutes, and coating thickness in μm.

Wind speed×(hot air temperature-20)×drying time/coating thickness&gt;48...(4)

Hot air temperature80°C....(5)

Drying time60 minutes...(6)

In addition, when the infrared absorption filter of the present invention is to improve light resistance, a UV absorber may be added to the infrared absorption layer. In addition, in order to make the infrared absorbing filter of the present invention weather resistant and solvent resistant, the polymer resin in which the infrared absorbing dye is dispersed in the infrared absorbing layer may be crosslinked with a crosslinking agent. (Raw material resin for transparent polymer film)

The resin of the present invention constituting the transparent polymer film made of the base material of the infrared absorbing layer includes, for example, polyester, acrylic, cellulose, polyethylene, polypropylene, polyolefin, polyvinyl chloride, and polyvinyl chloride. Carbonate-based, phenol-based, urethane-based resins, etc. are not particularly limited. Among them, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene 2,6-polyethylene terephthalate are preferred in terms of environmental load and cost. Especially polyethylene terephthalate (hereinafter referred to as PET) is suitable. The PET is explained in detail in the following examples.

The production of PET resin can use the conventional direct polymerization method of polycondensation through esterification reaction with p-acid and ethylene glycol as starting materials, or using dimethyl p-acid and ethylene glycol as starting materials, through esterification. The conventional transesterification method of exchange reaction and polycondensation. In the direct polymerization method, those contained in the PET resin such as polycondensation catalyst (Sb₂O₃, Sb glycolide, etc.), heat stabilizers (P-based compounds such as trimethyl phosphate), electrostatic addition method, adhesion improver (ethylene glycol soluble alkali metal salt, Alkaline earth metal salts, etc.). For the transesterification method, in addition to the above-mentioned compounds, transesterification catalysts (acetates of Mg, Ca, Zn, Mn, etc.) are required. Especially when using Sb₂O₃When used as a polycondensation catalyst, Sb₂O₃It will be reduced to metal Sb, and agglomerates will easily precipitate on the surface of the film. This is one of the reasons for the optical shortcomings of the film, so that the polycondensation time can be reduced as much as possible within the range that will not be significantly slow.₂O₃The content is better.

In order to make the foreign matter in the PET film with a size of 20μm or more per unit area is 10 pieces/m²Below, so that Sb in PET resin₂O₃The content of Sb element is 50~250ppm, preferably 50~200ppm, and most preferably 70~150ppm. In addition, PET resin generally contains inert particles and internally precipitated particles for the purpose of imparting slipperiness, etc., to increase In order to be transparent and reduce the foreign matter, it must be substantially free of such particles. Substantially free of particles means that the content of particles in the film is less than the detection threshold when analyzed by fluorescent X-ray.

In addition, at the end of the polycondensation, the PET resin is filtered with a pore size (95% cut) of 7 μm or less with a Naslon (transliteration) filter. When the molten resin is extruded into the cooling water in a monofilament form, the cooling water is filtered in advance ( Pore size: 1μm or less), and make this step a closed room, use a high filter to reduce the foreign matter of 1μm or more in the environment, so that the foreign matter of the size of 20μm or more in the PET resin as the base film raw material, in the film unit 10 pcs/m in area²The following are better.

In addition, the intrinsic viscosity of PET resin is preferably 0.45~0.70dl/g. The better is 0.50~0.67dl/g, and the best is 0.55~0.65dl/g. When the intrinsic viscosity is less than 0.45d1/g, cracks often occur during the production of the film, and the strong tensile properties are insufficient. In addition, if it exceeds 0.70 dl/g, the filtration pressure rises greatly, and high-precision filtration for removing foreign matter cannot be performed, so it is not a requirement. (Manufacture of transparent polymer film)

A. Manufacturing of unstretched film

After fully vacuum drying the PET resin that does not substantially contain inert particles and internally precipitated particles, it is supplied to an extruder and melted and extruded into a sheet at about 280°C. After cooling and hardening, the film is formed into an unstretched PET sheet. . At this time, when removing the foreign matter contained in the PET resin, the molten resin is stored at an arbitrary place at about 280°C, and when removing the foreign matter contained in the resin, the above-mentioned high-precision filtration is performed.

The filter material used for high-precision filtration of molten resin is not particularly limited. When the filter material of the stainless steel baking material is caused by the catalyst or additives in the raw material PET resin, the falling material from the wall of the reaction tank, and the external contamination Coarse foreign matter and high melting point organic matter, etc. Foreign matter with a size of 20μm or more, there are 10 pieces/m in the unit area of the film²The following is appropriate. The filter particle size (initial filtration efficiency 95%) of the filter material used for high-precision filtration of molten resin is preferably 15μm or less. When the filter particle size of the filter material is larger than 15μm, it is easy to make the removal of foreign matter over 20μm insufficient. By using a filter material with a filter particle size (initial filtration efficiency of 95%) of 15μm or less to perform high-precision filtration of molten resin, it is extremely important to obtain a PET film with fewer optical defects and excellent transparency when reducing productivity.

Even if there is a fine foreign matter passing through the filter material in the molten resin extrusion step, crystallization occurs around the foreign matter in the cooling step of the sheet-like melt, and this stretching step causes unevenness in the drawing and produces a small thickness difference. The state of the lens. The part of the light with the slight difference in thickness has the tortuosity or scattering of the lens, and is larger than the actual foreign matter when observed with the naked eye. The difference in thickness is the difference between the height of the convex portion and the depth of the concave portion. When the height of the convex portion is 1 μm or more, and the depth of the concave portion adjacent to the convex portion is 0.5 μm or more, the lens effect even the size of 20 μm The shape object is 50μm or more visible to the naked eye, and it is regarded as an optical defect of 100μm or more. In order to prepare the highly transparent film used in the present invention, it is preferable to use particles that substantially impart slippery properties in the base film. The higher the transparency, the more obvious the optical defect due to the microscopic unevenness. In addition, when the surface of the thick film is thin and the film is not easy to be quenched, for the purpose of crystallization, the entire film must be quenched when making an unstretched film.

The method of cooling the unstretched film is to extrude the molten resin from the mold in the rotating cooling roll into a sheet, and the sheet-like melt is adhered to the rotating cooling roll by electrostatic external densification and quenched into a sheet. Known method of the board. The method of cooling the air surface of the sheet-like object (the surface opposite to the surface in contact with the cooling roll), and the method of blowing a high-speed airflow to cool it is cooling.

B. Manufacturing of stretched film

The transparent polymer film of the base material of the infrared absorption filter of the present invention is preferably a film stretched in at least one axis direction, and more preferably a biaxially stretched film.

The resulting unstretched film is stretched 2.5 to 5.0 times in the length direction by a roll heated to 80 to 120°C to prepare a uniaxially aligned PET film. In addition, the end of the film is clamped with a clip, introduced into a hot air zone heated to 80~180°C, and stretched 2.5~5.0 times in the width direction after drying. Continuously introduce the heat treatment zone at 200~240°C for 1~60 seconds to complete the crystal alignment. In this heat treatment step, a relaxation treatment of 3-10% is applied to the width direction and/or the length direction as required.

C. Manufacturing of polymer easy-adhesive layer

In the present invention, a polymer easy-adhesive layer must be laminated on at least one side of the transparent polymer film. In any of the above-mentioned film manufacturing steps, the polymer easy-adhesive layer is coated, dried, The build-up is better.

The step of coating the aqueous coating liquid is usually a coating step, that is, a step of coating on a biaxially stretched and heat-fixed substrate. However, the method of the online coating step of coating in the film manufacturing step is more good. In addition, it is preferable to coat the substrate film before the crystal alignment is completed. Moreover, the cleanliness of the air in the coating step after the unstretched film is made (the number of particles above 0.5μ/ft³) It is extremely effective to reduce foreign matter adhering to the surface of the film by controlling the high filter to a level of 100,000.

After coating the coating liquid on the polyester film substrate after unstretched or uniaxially stretched, when drying and stretching, in the drying step after coating, only solvent components such as water are removed and the coating layer is selected The temperature and time at which the crosslinking reaction does not proceed are extremely important. The drying temperature is preferably 70~140°C, and the drying time is adjusted according to the coating liquid and the amount of coating, but the temperature difference between the temperature (°C) and the time (second) is preferably 3000 or less.

The solid content concentration in the aqueous coating liquid is preferably 30% by weight or less, and more preferably 10% by weight or less. The film coated and dried with the aqueous coating liquid is introduced into a stretcher during stretching and heat setting, and heated at this time to form a relatively stable film during the thermal crosslinking reaction to form a polyester-based laminated film. In order to obtain good adhesion with the ink, in the heat treatment step, heat treatment at 100°C or higher for more than 1 minute, and make the coating amount of the easy-adhesive layer 0.05g/m after the heat treatment.²It is better to be coated.

The coating method of the aqueous coating liquid can be performed by a conventional method. For example, there are reversible roll coating method, gravure method, casting method, roller brush method, spray coating method, air knife method, metal wire rod coating method, tube scraper method, impregnation coating method and screen coating method Etc., these methods can be used alone or in combination.

The polymer easy-adhesive resin laminated on the transparent polymer film of the present invention is not particularly limited. For example, there are water-based polyester resins, water-based polyurethanes, water-based acrylic resins, acrylic grafted polyester resins, and maleic acid. Grafted polyester resin, etc. Among them, the polymer resin with the copolymerized polyester resin (A) and polyurethane resin (B) as the main components has excellent adhesion between the substrate and the PET film or infrared absorption layer, and It has excellent adhesion to the anti-reflection layer or anti-glare treatment layer laminated on the outermost layer of the infrared absorption filter, and also has high transparency. Therefore, to provide the polymer easy-adhesive layer on the surface of the PET film laminated infrared absorption layer of the substrate and the surface of the PET film laminated anti-reflective layer or the anti-glare treatment layer of the substrate, especially by the copolymerization polymer An easy-adhesion layer made of a polymer resin whose main constituents are ester resins and polyurethane resins is preferred.

When the copolymerized polyester resin is used alone as the polymer resin that constitutes the polymer easy-adhesive layer, the adhesion to the PET film of the substrate is sufficient, but the reflection prevention layer laminated on the outermost layer of the infrared absorption filter or anti-glare treatment When the layer or the infrared absorbing layer is coated with a solvent system, the adhesiveness is insufficient.

Moreover, when polyurethane is used alone, the adhesion between the PET film of the substrate and the infrared absorption layer is not good.

The copolymerized polyester resin, which is a component of the polymer easy-adhesion layer, has a branched ethylene glycol component as a component. Examples of branched ethylene glycol components include 2,2-dimethyl-1,3-propanediol, 2-methyl-2-ethyl-1,3-propanediol, and 2-methyl-2-butyl-1. ,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-methyl-2-isopropyl-1,3-propanediol, 2-methyl-2-n-hexyl-1, 3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-n-butyl-1,3-propanediol, 2,2-di-n-butyl-1,3-propanediol, 2-n-butyl-2-propyl-1,3-propanediol, 2,2-di-n-hexyl-1,3-propanediol, etc.

The above-mentioned branched ethylene glycol component preferably contains 10 mol% or more in all ethylene glycol components, and more preferably 20 mol% or more. The ethylene glycol component other than this compound is best ethylene glycol. If it is a small amount, it is better to use diethylene glycol, propylene glycol, butanediol, hexanediol, or 1,4-cyclohexanedimethanol.

The dicarboxylic acid component of the above-mentioned copolymerized polyester resin is the best for acid and isocyanic acid. If it is a small amount, add other dicarboxylic acids such as diphenylcarboxylic acid, 2,6-dicarboxylic acid and other aromatic dicarboxylic acids for copolymerization.

For the acid component other than the dicarboxylic acid component, it is preferable to use 1-10 mol% 5-sulfoiso acid for imparting water dispersibility, such as sulfo-p-acid, 5-sulfo-iso Acid, 4-sulfoyliso acid-2,7-dicarboxylic acid, 5-(4-phenoxy)iso acid and its salts, etc.

Polyurethanes of other constituents of the polymer easy-adhesive layer include, for example, block-type isocyanate group-containing resins, terminal isocyanate groups to be chain-blocked with hydrophilic groups (hereinafter referred to as block), and heat-reactive water-soluble Urethane and so on. The isocyanate group blocking agent includes, for example, bisulfites and phenols, alcohols, lactones, ketones, and active methylidene compounds containing sulfonic acid groups. The blocked isocyanate group makes the urethane prepolymer hydrophilized or water-solubilized. When heat energy is applied to the resin during the drying or heat fixation process during film production, in order to release the blocking agent from the isocyanate group, the resin is a water-dispersible copolymerized polyester mixed into the self-crosslinked mesh The resin is immobilized and reacts with the end groups of the resin. The resin used in the adjustment of the coating solution is hydrophilic, so it has poor water resistance. However, after coating, drying, heat fixing, and completion of the thermal reaction, the hydrophilic group of the urethane resin, that is, the blocking agent, is released. A coating film with good water resistance can be obtained. Within the blocker, with appropriate heat treatment temperature and heat treatment time, bisulfites are the best among industrial users.

The chemical composition of the urethane prepolymer used in the above resin is (1) a compound with a molecular weight of 200 to 20,000 with more than 2 active hydrogen atoms in the molecule, and (2) a compound with more than 2 in the molecule Organic polyisocyanate of isocyanate group, or compound of terminal polyisocyanate group obtained by reaction of compounds with at least 2 active hydrogen atoms in the molecule (chain extender) as required by these (1) + (2), (3) .

The compound of (1) is generally known, for example, the terminal or molecule contains more than two hydroxyl, carboxyl, amine or thiol groups. The preferred compounds are polyether polyols and polyether ester polyols, etc. .

Polyether polyols include, for example, alkylene oxides such as ethylene oxide and propylene oxide, or compounds that polymerize styrene oxide and epichlorohydrin, etc., or perform random polymerization or block polymerization. Or the compound obtained by the addition polymerization of polyol. Polyethylene glycol and polyetherester polyol are mainly linear or branched compounds, for example. These polyols can be combined with succinic acid, adipic acid, acid and maleic anhydride, etc., and ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl alcohol, 1,6- Saturated or unsaturated polyols such as hexanediol and trihydroxypropane, polyalkylene ether glycols such as lower molecular weight polyethylene glycol and polypropylene glycol, or mixtures of these alcohols are condensed.

In addition, polyester polyols can use polyesters obtained from lactones and hydroxy acids, and polyetherester polyols can use polyethers obtained by adding ethylene oxide or propylene oxide to polyesters produced in advance. Esters.

The organic polyisocyanate of (2) includes, for example, isotropic bodies of toluene isocyanate, aromatic diisocyanates such as 4,4-diphenylmethane diisocyanate, aromatic aliphatic diisocyanates such as xylene diisocyanate, and isophor Alicyclic diisocyanates such as ketone diisocyanate and 4,4-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, and aliphatic diisocyanates such as 2,2,4-trimethylhexamethylene diisocyanate Or polyisocyanates which are preliminarily added with trimethylolpropane or the like, or used alone or in combination of several kinds of these compounds.

The chain elongation agent with at least 2 active hydrogens of (3) includes, for example, ethylene glycol, diethylene glycol, 1,4-butanediol, and 1,6-hexanediol, etc. Polyols such as alcohol, trimethylolpropane, and pentaerythritol, diamines such as ethylenediamine, hexamethyldiamine, and pyridine, amino alcohols such as monoethanolamine, and diethanolamine, and thiodiethylene glycol Such as sulfur-based diethylene glycols, or water. To synthesize the urethane of (3), usually by using the one-stage or multi-stage isocyanate polyaddition method of the chain extender, at a temperature below 150°C, preferably 70~120°C The reaction time is 5 minutes or several hours. If the ratio of isocyanate groups to active hydrogen atoms is 1 or more, it can be freely selected, but free isocyanate groups must remain in the obtained urethane prepolymer.

In addition, when the content of free isocyanate groups is 10% by weight or less, it is preferably 7% by weight or less in consideration of the stability of the urethane polymer aqueous solution after blocking. The obtained urethane prepolymer is preferably blocked by using bisulfite. Mix with the bisulfate aqueous solution and fully stir and react within 5 minutes to 1 hour. The reaction temperature is preferably 60°C or less. Then, it is diluted with water to an appropriate concentration to form a heat-reactive water-soluble urethane composition. The composition is adjusted to an appropriate concentration and viscosity during use. Usually, when heated at around 80~200°C, in order to dissociate the bisulfite of the blocking agent and regenerate the active isocyanate group, it has the advantage of The property of causing polyaddition reaction within or between molecules of the polymer to generate polyurethane polymer, or causing the addition of other functional groups.

The block-type isocyanate group-containing polyurethane resin (B) has, for example, the trade name Yella Stoneron (transliteration) manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd. Yella Stunron is a product that blocks isocyanate groups with sodium bisulfite, and has a strong hydrophilic amino methionate sulfonate group at the molecular end, so it is water-soluble.

When mixing the branched ethylene glycol component-containing copolymerized polyester resin (A) and the block type isocyanate group-containing polyurethane resin (B) used in the present invention to prepare a coating solution, the resin (A) ) And the weight ratio of the resin (B) (A): (B)=90:10~10:90, the better, even better (A): (B)=80:20~20:80. When the weight ratio of the resin (A) to the total solid content of the easy-adhesive layer is less than 10%, the coating solution for the substrate becomes insufficient, and the adhesion between the polymer easy-adhesive layer and the substrate film becomes insufficient insufficient. In addition, when the weight ratio of the resin (B) to the total solid content of the easy-adhesive layer is less than 10%, it is difficult to obtain practical adhesion in the UV-curable hard coating.

In the aqueous coating liquid used in the present invention, a catalyst can be added to promote the thermal crosslinking reaction. For example, inorganic substances, salts, organic substances, alkaline substances, acidic substances, metal-containing organic compounds, etc., various chemistries can be used. substance. Moreover, to adjust the pH value of the aqueous solution, an alkaline substance or an acidic substance can be added.

When the aqueous coating liquid is applied to the surface of the substrate film, in order to improve the wettability of the film and to uniformly coat the coating liquid, a necessary amount of conventional anionic active agent and nonionic interface can be used Active agent. In addition to water, the solvent used in the coating liquid can be mixed with alcohols such as ethanol, isopropanol, and hexanol that account for less than 50% by weight in the total coating liquid. In addition, if it is 10% by weight or less, organic solvents other than alcohols are mixed within the soluble range. However, the total of alcohols and other organic solvents is less than 50% by weight.

If the addition amount of the organic solvent is less than 50% by weight, it has the effect of improving the dryness during coating drying and the effect of improving the appearance of the coating film when compared with water only. If it is more than 50% by weight, the solvent will evaporate quickly, the concentration of the coating liquid during coating will change, the viscosity will increase, and the coatability will decrease. Therefore, the appearance of the coating film will deteriorate and there is a risk of fire.

Since the present invention does not contain particles for the purpose of imparting slipperiness in the base film, it is in terms of film rationality (smoothness, curling, blocking resistance), rubbing resistance, abrasion resistance, etc. It is preferable that the aqueous coating liquid contains particles and forms appropriate protrusions on the surface of the easy-adhesive layer. The particles include, for example, inorganic particles such as calcium carbonate, calcium phosphate, silica, kaolin, talc, titanium dioxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, molybdenum sulfide, cross-linked polymer particles, and calcium oxalate. And other organic particles. Among these, since the refractive index of silica particles and polyester resin is close, and a film with high transparency can be obtained, it is the best.

The diameter of the particles contained in the aqueous coating liquid is preferably 0.01 to 1.0 μm, more preferably 0.03 to 0.5 μm. If the average particle size is greater than 1.0 μm, the surface of the film will be roughened and the transparency of the film will tend to decrease. In addition, if the average particle size is less than 0.01 μm, the smoothness, curling, and blocking properties of the film are insufficient.

Two or more kinds of these particles may be blended in the easy-adhesive layer, or those made of the same kind of particles with different particle diameters may be used together. For any of them, it is preferable that the average particle diameter of the whole particles and the total content satisfy the above-mentioned range.

When applying the coating liquid to remove the coarse aggregates of particles in the coating liquid, it is better to arrange the coating liquid with a filter material for precision filtration before coating.

In order to make the filter particle size of the filter material used for the precision filtration of the coating liquid used in the present invention be 25μm or less (initial filtration efficiency 95%), it is the unit of the polymer easy-adhesive layer on the surface and/or inside of the polymer easy-adhesive layer 3 pcs/m in area²Larger objects with a maximum diameter of 100μm or more. The size of the filter material that cannot be removed is coarse aggregates of 25μm or more. Many coarse aggregates that cannot be removed after coating and drying, during uniaxial stretching or biaxial stretching of the easy-to-adhesive layer, will cause the coarse aggregates to change due to tensile stress. It becomes agglomerates of more than 100μm, resulting in many optical defects.

The filter material type for the precision filtration of the coating liquid should be those having the above-mentioned performance, and there is no particular limitation. For example, there are a monofilament type, a blanket type, and a mesh type. For the precision filtration of the coating liquid, the filter material should only have the ability to remove the above-mentioned coarse aggregates and will not adversely affect the coating liquid. There are no special restrictions. For example, there are stainless steel, polyethylene, polypropylene, and The material of dragon etc.

In the range where the water-based coating liquid finally does not impair adhesion and transparency, in addition to particles, various additives such as anti-static properties, anti-ultraviolet absorption properties, plasticizers, antibacterial agents, pigments, and lubricants can be mixed.

The thickness of the resulting transparent polymer film with an easy-adhesive layer is preferably 50-300 μm, more preferably 100-250 μm. When the film thickness is less than 50 μm, the rigidity is insufficient, so it is not a requirement. Conversely, when the film thickness is greater than 300 μm, the foreign matter with optical defects in the film increases and the total light transmittance decreases, so it is not a requirement.

In addition, in the transparent polymer film with easy-adhesive layer, there must be 10 pcs/m in the unit area of the film²Foreign objects with a size of 20μm or more, preferably 8 pieces/m², The better is 6/m². If the size of the foreign objects above 20μm exceeds 10/m²At this time, the haze value of the entire film increases and the total light transmittance decreases. In addition, it becomes the cause of optical defects, so it is not suitable as an infrared absorption filter.

In order to make the foreign matter larger than 20μm in the film unit area is 10 pieces/m²In the following, as described above, for example, when PET resin as a raw material for a film is used, the following method is suitable.

(1) Sb used as a polycondensation catalyst in the production of PET₂O₃The content is less than general (for PET, Sb element is preferably 50~250ppm, more preferably 50~200ppm, and best is 70~150ppm).

(2) It does not substantially contain inert particles and internally precipitated particles.

(3) When the polycondensation is completed, the PET resin is filtered with a Naslon filter with a pore size (95% cut) of 5 μm or less, and the molten resin is extruded in the cooling water into a monofilament, and the cooling water is filtered in advance. (Aperture: 1μm or less), this step is treated with a mesh, and foreign matter of 1μm or more in the environment is removed with a high filter.

(4) During the manufacture of PET film, use the extrusion step to make PET resin into a high-precision pass rate (filter particle size of the initial filtration efficiency of 95% of the filter material: 15μm).

The transparent polymer film of the base material of the infrared absorption filter of the present invention preferably has a haze value of 1% or less. More preferably, it is 0.8% or less, and the best is 0.6% or less. If the haze value is greater than 1%, the image sharpness of the display using the infrared absorption filter with the transparent polymer film as the base material will decrease, so it is not a requirement. In order to make the haze value less than 1%, the film contains substantially no inert particles and internal precipitated particles, and removes the above-mentioned coarse foreign matter, and uses a copolymerized polyester resin and polyurethane The polymer resin whose main constituent is resin is very effective as the resin constituting the polymer easy-adhesive layer.

(Manufacturing of infrared absorption filter)

An infrared absorbing layer is laminated on at least one surface of the transparent polymer film obtained as described above. The lamination of the infrared absorption layer can be on the easy-adhesive surface of the transparent polymer, or on the non-adhesive surface.

However, when manufacturing an infrared filter with an infrared absorption layer laminated on both sides of a transparent polymer film, it is not easy to roll into a roll during mass production in order to make both sides of the film smoother than the infrared absorption layer. Here, by including inert particles on at least one surface of the infrared absorbing layer and forming irregularities on the surface of the infrared absorbing layer, it is desired to improve the processing characteristics such as smoothness, curling, and blockiness. The inert particles are preferably mixed with a polymer resin in which an infrared absorbing dye is dispersed. In terms of transparency, inert particles use metal oxides such as silica, alumina and other metal oxides, fluorine-based resins, acrylic resins, and polyester-based resins with a wavelength shorter than the wavelength of visible light and an average particle size of 0.01 to 0.1 μm. The particles.

When laminating an infrared absorbing layer on at least one side of the transparent polymer film of the base material, dissolve the polymer resin with a solvent such as methyl ethyl ketone, tetrahydropyran, toluene, and then apply the coating solution for dispersing the infrared absorbing pigment on The base film is preferably dried on at least one side.

The infrared absorption filter of the present invention has an infrared absorption layer mainly composed of an infrared absorption dye and a polymer resin. The infrared absorbing filter can use the infrared absorbing layer alone, or the infrared absorbing layer can be laminated on the transparent substrate by the co-extrusion method or the coating method. Among them, a coating method of dispersing the infrared absorbing dye in a polymer resin and a solvent, coating the coating liquid on a transparent substrate and drying it is preferred. By using the coating method to laminate the infrared absorbing layer on the transparent substrate, the infrared absorbing filter can be easily manufactured, which can correspond to small-volume production.

When the infrared absorbing layer is coated on both sides of the base film, the method is not particularly limited. For example, the following method can be used. For example, by installing several coating heads on one coating line, coating on both sides at the same time, and drying both sides at the same time, or coating and drying one side first, and then drying the other side.

In the infrared absorption filter of the present invention, it is preferable to laminate an electroplated metal conductive layer on the same side as or on the reverse side of the infrared absorption layer. By stacking electroplated metal conductive layers, harmful electromagnetic waves emitted from the display can be removed.

For the electroplated metal conductive layer, a metal sheet with high conductivity may be etched into a mesh shape, or a woven net of metal fibers, or a fiber attached by methods such as metal plating on the surface of polymer fibers.

The aperture ratio of the metal mesh used in the electromagnetic wave absorbing layer is preferably 50% or more when considering the use of the display. The metal used in the electromagnetic wave absorption layer may be any metal with high conductivity and good stability, and there is no particular limitation. In terms of workability and cost, copper, nickel, tantalum, etc. are preferred.

In addition, when the infrared absorption filter of the present invention improves the scratch resistance of the outermost layer, a hard coating layer (HC) can be provided. The hard coating treatment layer (HC) is a single or mixed polyester resin, urethane resin, acrylic resin, melamine resin, epoxy resin, polysiloxane resin, polyamide resin A cross-linkable resin cured product layer of a curable resin such as an amine resin is preferred.

The thickness of the hard coating treatment layer (HC) is preferably 1-50 μm, more preferably 2-30 μm. If the thickness is less than 1 μm, the scratch resistance is insufficient. On the contrary, if the thickness is greater than 50 μm, the coating speed of the hard coat resin becomes slow, and productivity is poor.

The method of laminated hard coating treatment layer (HC) is to coat the other side of the transparent polymer film with the infrared absorption layer by gravure method, reversible method, mold method, etc. after coating, external heating, ultraviolet light, electronic wire, etc. The energy hardening method is better.

In addition, when the infrared absorption filter of the present invention improves the visibility when using a plasma display or the like, an anti-glare treatment layer (AG) may be provided on the outermost layer. The anti-glare treatment layer (AG) is made by applying a curable resin, drying, and forming irregularities on the surface with a printing roller, and then curing by external heating, ultraviolet rays, electron beams, and other energy. The curable resin is a single or a mixture of polyester resin, urethane resin, acrylic resin, melamine resin, epoxy resin, polysiloxane resin, polyimide resin, etc. Better.

In addition, when using the infrared absorption filter of the present invention as a display, an antireflection treatment layer (AR) may be provided on the outermost layer in order to further increase the transmittance of visible light. The anti-reflection treatment layer (AR) is preferably laminated with a single layer or two or more layers, preferably with a material having a refractive index different from that of the plastic film. When it is a single-layer structure, a material with a lower refractive index than a plastic film can be used. Moreover, in the case of a multi-layer structure with two or more layers, it is better to use a material with a refractive index larger than that of the plastic film on the layer adjacent to the plastic film, and it is better to select a material with a smaller refractive index for the layer on it. The material constituting the antireflection treatment layer (AR) is not particularly limited as long as it satisfies the above-mentioned refractive index relationship and can use organic or inorganic materials. For example, CaF is used.₂, MgF₂, NaAlF₄, SiO₂, ThF₄, ZrO₂, Nd₂O₃, SnO₂, TiO₂, CeO₂, ZnS, In₂O₃The dielectric body of the same is better.

The layering method of the anti-reflection treatment layer (AR) can be a dry coating step such as a vacuum evaporation method, a sputtering method, a CVD method, an ion coating method, etc., or a gravure coating method, a reversible method, or a mold Method and other wet coating steps.

In addition, before laminating the hard coat treatment layer (HC), anti-glare treatment layer (AG), and anti-reflection treatment layer (AR), pre-treatments such as corona discharge treatment, plasma treatment, sputter etching treatment, Conventional treatments such as electron beam irradiation treatment, ultraviolet irradiation treatment, plasma treatment, easy bonding treatment, etc.

The infrared absorption filter of the present invention has less foreign matter in the base film and less optical defects. The infrared absorption filter of the present invention has a maximum transmittance of 30% or less in the near infrared range of wavelength 800nm to 1100nm, and the difference between the maximum and minimum transmittance of the visible light range of 450nm to 650nm is 10% or less, and The transmittance at a wavelength of 550nm can meet 50% or more, absorption in the near-infrared range, high light transmittance in the visible light range, and no large absorption at a specific wavelength in the visible light range, with a dark gray hue. Moreover, it can still meet the transmittance and have excellent environmental stability after being placed for 500 hours in an atmosphere with a temperature of 60°C and a humidity of 95%. In addition, the infrared absorption filter of the present invention has a transmittance of 10% or less in the infrared range with a wavelength of 900 to 1100 nm. By making the transmittance of the near-infrared range low, when used in a plasma display or the like, it can absorb unnecessary infrared radiated from the display, and can prevent the wrong operation of the remote controller using infrared.

In addition, the infrared absorption filter of the present invention has a minimum transmittance of 60% or more in the visible light range with wavelengths of 440 to 500 nm and 640 nm to 700 nm, and a maximum transmittance of 60% or less in the visible light range with wavelengths of 550 to 600 nm. When the spectral characteristics of the infrared absorption filter are within the above range, the hue is blue-gray, and the edge of the hue emitted from the display is better when it is in front of the display. Especially in plasma displays, the luminous intensity of blue is weaker than that of green or red. Therefore, it is necessary to make the transmittance of the visible light range of 540~600nm smaller in order to correct it. In addition, the transmittance at a wavelength of 550 nm is preferably 50% or more. Moreover, when the transmittance in this wavelength range is 50% or less, when a filter with the above-mentioned spectral characteristics is installed in front of the display, a very dark display will be formed, so it is not a requirement. Since the infrared absorption filter of the present invention has a blue-gray hue, it can be used in plasma display screens (PDP), liquid crystal displays (LCD), CAD systems and other remote control error prevention filters, video recorder visual sensitivity correction filters, Hot wire absorption filter, etc.

[Examples]

Next, examples are used to describe in detail the manufacturing method of the infrared absorption filter of the present invention, but the present invention is not limited by these. The "parts" used in the examples and comparative examples mean "parts by weight" when there is no particular limitation. Furthermore, the characteristic values used in this specification were evaluated in the following method.

(1) Inherent viscosity of polyester resin

In a mixed solvent of 1,1,2,2-tetrachloroethane/phenol (weight ratio: 2/3), calculate the viscosity of the solution at 30°C.

(2) Adhesion to light-curing acrylic coating

On the easy-adhesive layer obtained in the examples and comparative examples, a hard coating agent (Cicabim EXF01(B)) manufactured by Dainichi Seika Co., Ltd. was coated with a #8 iron wire rod, and the temperature was 70°C. After drying for 1 minute to remove the solvent, use a high-pressure mercury lamp 200mJ/cm², Under the conditions of irradiation distance of 15cm and walking speed of 5m/min, a hard coating layer with a thickness of 3μm is formed. The adhesiveness of the obtained film was determined by the standard test method described in 8.5.1 of JIS-K5400.

Specifically, 100 mesh-like scratches that penetrate the easy-adhesive layer to reach the base film are cut guides with a slit interval of 2 mm. Then, cellophane tape (No. 405 made by Japanese company: 24mm width) was attached to the scratched surface of the mesh, wiped with an eraser to be completely adhered, and peeled off vertically, and the number of meshes remaining on the easy-adhesive layer was calculated visually. The formula is used to obtain adhesion. Part of the residual hard coating layer on the mesh is divided by the number of meshes remaining on the easy-adhesive layer.

Adhesion (%) = (number of remaining meshes/number of initial meshes)×100

(3) The size of foreign matter in the film and coarse aggregates in the coating liquid

The optical defect detection device described below is used to detect optical defects with a size of more than 50μm on 16 sheets of 250mm×250mm film.

(Detection principle of optical defects)

Place the fluorescent lamp of 20W×2 lamp as the light projector on the 400mm below the XY table, and set the light cover with the slit width of 10mm. Connect the light projector and the light vending device, measure the angle between the vertical direction of the film surface and the eggplant shape to be 12 degrees. When the light is incident, when there are optical defects remaining on it, the part flashes brightly, so that the amount of light is arranged 500mm above the XY table The CCD image sensor camera transforms the electrical signal, broadens the electrical signal, differentiates it, compares it with a comparator with a critical value, and outputs the detection signal of the optical defect. Moreover, the video signal input from the CCD image sensor camera is used to calculate the size of the optical defect by the image sequence to indicate the position of the optical defect of the set size.

Using this optical defect detection device, the defect part of the self-detection is selected by foreign matter and optical defects are selected by coarse aggregates in the coating liquid, and cut into appropriate sizes, and measured by a microscope with a measuring device. The size when viewed in the vertical direction.

When there is an optical defect due to a foreign body, measure the maximum diameter of the foreign body and calculate the unit area (1m²The number of foreign objects with a size of 20 μm or more in the film, in other words, the foreign objects with a size of 20 μm or more in the film, the number of foreign objects with a maximum diameter of 20 μm or more that exist in the film when viewed from a vertical plane (pieces/ m²)。

For the coarse aggregates in the coating solution, measure the maximum diameter of the coarse aggregates and obtain the unit area of the easy-adhesive layer (1m²) The number of foreign objects whose size is more than 100μm. In other words, it refers to the number of aggregates with a size of 100 μm or more in the easy-adhesive layer and the number of foreign objects with a maximum diameter of 100 μm or more existing on the surface and inside of the easy-adhesive layer (pieces/m²)。

(4) Haze value

It was measured using a haze measuring device (model TC-H3DP manufactured by Tokyo Denshoku Kogyo Co., Ltd.) based on JIS-K7105.

(5) Spectroscopic characteristics

Use a self-counting spectrophotometer (Hitachi U-3500) and measure in the wavelength range of 1500~200nm.

(6) Environmental stability

After leaving the sample for 500 hours in an atmosphere with a temperature of 60°C and a humidity of 95%, the spectroscopic characteristics described above are measured.

Example 1

(1) Adjustment of coating liquid for polymer easy-adhesive layer

In the present invention, the coating liquid used for the polymer easy-adhesive layer laminated on the transparent polymer film is prepared by the following method.

Add 95 parts by weight of dimethyl p-acid, 95 parts by weight of dimethyl isocyanate, 35 parts by weight of ethylene glycol, 145 parts by weight of neopentyl alcohol, 0.1 parts by weight of zinc acetate and 0.1 parts by weight of trioxide in the reaction vessel. Antimony, the transesterification reaction was carried out at 180°C for 3 hours. Then, 6.0 parts by weight of 5-sodium isocyanic acid was added, and the transesterification reaction was carried out at 240°C for 1 hour, and then the polycondensation reaction was carried out at 50°C under reduced pressure (13.3~0.267hPa) within 2 hours to produce A polyester resin with a molecular weight of 19,500 and a softening point of 60°C was obtained.

A 30% by weight aqueous dispersion of the polyester resin (A) obtained by mixing 6.7 parts by weight each, and 40 parts by weight of a cyanate group-containing self-crosslinking polyurethane resin (B) blocked with sodium bisulfate 20% by weight aqueous solution (manufactured by Daiichi Kogyo Pharmaceutical: trade name Yella Stonlong H-3), 0.5 parts by weight of Yella Stonlong catalyst (Cat64), 44.3 parts by weight of water and 5 parts by weight of isopropanol , 0.6 parts by weight of 10% by weight aqueous solution of anionic surfactant, 1.8 parts by weight of spherical silica particles A (manufactured by Nissan Chemical Industry Co., Ltd.: Strodex OL, average primary particle size 40nm) of 20% by weight 4 weights of water dispersion, 1.1 parts by weight of dry-process silica particles B (manufactured by Ayero Giro Co., Ltd.: Ayero Giro O×50, average particle size 500nm, average primary particle size 40nm) % Water dispersion was used as a coating liquid (hereinafter referred to as coating liquid AB).

(2) Manufacturing of PRT resin for base film

When the temperature of the esterification reaction tank reached 200°C, a slurry of 86.4 parts by weight of para-acid and 64.4 parts by weight of ethylene glycol was added, stirred, and 0.017 parts by weight of antimony trioxide as a catalyst and 0.16 were added. Parts by weight of triethylamine. Then, pressurize and raise the temperature, at a gauge pressure of 3.5kg/cm², The pressure esterification reaction is carried out under the condition of 240°C. The inside of the esterification reaction tank was returned to normal pressure, and 0.071 parts by weight of magnesium acetate tetrahydrate and 0.014 parts by weight of trimethyl phosphate were added. Then, the temperature was raised to 260° C. within 15 minutes, and 0.012 parts by weight of trimethyl phosphate and 0.0036 parts by weight of sodium acetate were added. After 15 minutes, the obtained esterification reaction product was transferred to a polycondensation reaction tank, and the temperature was increased from 260°C to 280°C under reduced pressure, and the polycondensation reaction was carried out at 285°C. After the end of the polycondensation reaction, filtration was performed with a 95% cut filter made of Naslon with a diameter of 5 μm. In a closed room where foreign matter of 1μm or more in the air is reduced by a high filter, use pre-filtered cooling water (pore size: 1μm or less) to extrude the molten resin from the nozzle, and cut the monofilament PET resin to produce a PET sheet . The obtained PET sheet (A) has an intrinsic viscosity of 0.616dl/g, an Sb content of 144ppm, a Mg content of 58ppm, a P content of 40ppm, a color L value of 56.2, and a color b value of 1.6. It contains substantially no inert particles and Particles are deposited inside.

(3) Film making of easy-adhesive film

The above-mentioned PET sheet was used as a raw material for a film, and after drying under reduced pressure at 135°C for 6 hours (1.33 hPa), it was supplied to an extruder. At this time, use a stainless steel baking filter material with a filter particle size (initial filtration efficiency of 95%) of 15 μm for the molten resin for filtration treatment. Then, the molten resin at about 280°C is melted from the mold and extruded into a sheet, and the surface temperature is kept at about 20°C on a metal cooling roll (cold roll) that is quenched and hardened by applying static electricity to produce an undrawn sheet with a thickness of about 1400μm. Stretching film.

Next, the unstretched film was heated to 100°C using a heated roll group and an infrared heater, and then stretched 3.5 times in the longitudinal direction by a roll group with a peripheral speed difference to obtain a uniaxially oriented PET film.

Then, the coating liquid was precision filtered with a monofilament polypropylene filter medium with a filter particle size (initial filtration efficiency of 95%) of 25 μm, and was coated and dried on one side of the uniaxially aligned PET film by a reversible roller method. Moreover, after the unstretched cast film is manufactured, the mesh degree in the air in the coating step (the number of particles above 0.5μ/ft³) Controlled by a high-grade filter of 100,000. Subsequently, the end of the film was clamped with a clip, the coating layer was dried at 80°C for 20 seconds in the preheating zone of the spreader, and then pulled down at 130°C with the transverse stretch zone in the width direction Stretched 4.0 times. Then heat-fixing treatment is performed at 240°C, and 3% horizontal buffer treatment is performed at 200°C. A biaxially oriented PET film with a thickness of 100μm and an easy-adhesive layer was prepared. In addition, the coating amount as a solid content is 0.10g/m². The resulting biaxially oriented PET film with an easy-adhesive layer is substantially free of particles in the film, and the maximum diameter of foreign matter above 20μm in the film is 6/m², The number of foreign objects with a maximum diameter of 100μm or more on the surface and inside of the easy-to-bond layer is 3/m²。

(4) Manufacturing of polymer resin for infrared absorption layer

The base polyester of the dispersant was made by the following method.

Put it in an autoclave equipped with a thermometer and a mixer

136 parts by weight of dimethyl p-acid

58 parts by weight of dimethyl isocyanate

96 parts by weight of ethylene glycol

137 parts by weight of tricyclodecane dimethanol

Antimony trioxide 0.09 parts by weight

Heat at 170~220°C for 180 minutes to carry out the transesterification reaction. Then, the temperature of the reaction system was increased to 245°C, and the pressure in the system was 1:33~13.3hPa to continue the reaction for 180 minutes. As a result, a copolymerized polyester resin (A1) was obtained. The inherent viscosity of the copolymerized polyester resin (A1) is 0.41dl/g, the glass transition temperature is 90°C, and the specific gravity is 1.245.

Furthermore, the composition ratio of the constituent components of the copolymerized polyester resin (A1) analyzed by NMR is

Acid component

To acid 71 mol%

Iso-acid 29 mol%

Alcohol component

Ethylene glycol 28 mole%

Tricyclodecane dimethanol 72 mol%

(5) Manufacturing of infrared absorption filter

The solvent of the composition shown in Table 1, the above-mentioned copolymerized polyester resin (A1), and the infrared absorbing dye were added to the flask, heated, stirred, and dissolved to prepare a coating liquid for infrared absorbing layer. The coating liquid for the infrared absorption layer was coated on the easy-adhesive layer of the easy-adhesive PET film substrate using an applicator with a cap of 50 μm, and dried at a drying temperature of 90° C. for 1 hour to prepare an infrared absorption filter. After drying, the thickness of the coating layer is 12μm, and the amount of residual solvent is 1% by weight.<img file="TW472158B_D0007.tif" /><img file="TW472158B_D0008.tif" />

The color of the obtained infrared absorption filter was black-gray visually. Figure 1 shows its spectral characteristics. As shown in Figure 1, the infrared absorption filter absorbs flat in the visible light range of wavelength 400nm~650nm, and the transmittance difference of wavelength 400nm~650nm is less than 10%. There is strong absorption when the wavelength is above 700nm, and the maximum transmittance at the wavelength of 800nm~1100nm is below 30%. In addition, the transmittance at a wavelength of 550nm is more than 50%. Moreover, the haze value of the easy-adhesive PET film substrate is 0.5%, which is extremely small and highly transparent.

The obtained infrared absorption filter was placed in an atmosphere with a temperature of 60°C and a humidity of 95%RH for 500 hours. When the spectral characteristics were measured again, a slight color change was seen as shown in Figure 2 and the infrared absorption characteristics were maintained. In addition, when the filter is arranged in front of the plasma display, the color does not change, the controllability can be improved, and the emission of infrared rays can be reduced.

Example 2

Using the infrared absorption filter manufactured in Example 1, a hard coat layer (HC) was provided on the transparent polyester film surface opposite to the infrared absorption layer of the above infrared absorption filter. The hard coating agent uses a UV-curable resin composition in which 4 parts of benzophenone are added to 100 parts of epoxy acrylic resin, and the film is formed by the bar coating method and then pre-dried at 80°C for 5 minutes. 500mJ/cm²The ultraviolet radiation will harden it. The thickness of the hard coat layer (HC) after hardening is 5 μm.

Then, a copper foil with a thickness of 9 μm was bonded on the infrared absorption layer via a UV curable adhesive, and the bonded copper foil was patterned with a photoresist, and an etching process was performed to form an electromagnetic wave protection layer. At this time, the line width of the copper foil is 15μm, the peak is 115μm, and the aperture ratio is 75%.

The spectral characteristics of the infrared absorption filter in which the hard coating layer, the electromagnetic wave protection layer, and the infrared absorption layer are simultaneously laminated as described above are shown in Fig. 3. As shown in Fig. 3, it can be seen that the transmittance difference of the infrared absorption filter at wavelengths of 400nm to 650nm is 10% or less. The maximum transmittance at the wavelength of 800nm~1100nm is less than 30%. In addition, the transmittance at a wavelength of 550nm is 50% or more, absorbs infrared rays, and has a gray color tone, and absorbs electromagnetic waves, and has high visible light transmittance.

In addition, the obtained infrared absorption filter was placed in an atmosphere with a temperature of 60°C and a humidity of 95%RH for 500 hours. When the spectral characteristics were measured again, a slight color change was seen, but the infrared absorption characteristics were maintained.

Comparative example 1

(3) Easy-adhesive film

Except for adding to the esterification reaction tank, the average particle size of the PET resin (B) for the film (centrifugal precipitation type light transmission type particle size distribution measurement method: Shimadzu Corporation SA-CP3) is 1.0μm of ethylene dioxide particles of silicon dioxide Alcohol slurry (11% by weight), after the second addition of trimethyl phosphate, 2000ppm is added as silica particles to the formed PET resin, and after the completion of the polycondensation reaction, the diameter of 28μm is cut at 95%. A PET resin was prepared in the same manner as in Example 1 except that the filter made by Nasron was subjected to filtration treatment. The obtained resin (B) has an intrinsic viscosity of 0.616 dl/g, an Sb content of 144 ppm, a Mg content of 58 ppm, a P content of 40 ppm, a color L value of 57.6, a color b value of 1.2, and 2000 ppm for PET.

The above non-particle-free PET resin (A) and the above-mentioned silica particle-containing PET resin (B) are mixed in a weight ratio of 90:10, and filter particles are used when the molten resin is filtered through the melting and extruding step of the PET resin The size (initial filtration efficiency: 95%) is 20 μm, except for the baked filter material made of stainless steel. In the same manner as in Example 1, a biaxially oriented PET film with an easy-adhesive layer on one side was prepared. The obtained biaxially oriented PET film with easy-adhesive layer contains foreign objects in the film, and the number of foreign objects with a maximum diameter of more than 100 μm existing on the surface and inside of the easy-adhesive layer is shown in Table 3.

(5) Manufacturing of infrared absorption filter

In Example 1, the composition of the coating liquid for the infrared absorption layer is shown in Table 2. The specific gravity of the polymer resin which is changed to the composition of the infrared absorption layer is 1.26 and the glass transition temperature is 67 °C copolymerized polyester resin ( Toyobo Co., Ltd., Bailong RV200), and using a diimonium salt-based compound alone as an infrared absorbing dye, a coating liquid for an infrared absorbing layer was prepared in the same manner as in Example 1. On the above-mentioned biaxially oriented PET film, use an applicator with a lid of 100μm to coat the infrared absorbing layer coating liquid on the surface of the easy-adhesive layer of the above-mentioned biaxially oriented PET film, and dry it at a drying temperature of 90°C for 1 hour. An infrared absorption filter was prepared. After drying, the thickness of the coating layer is 25μm, and the amount of residual solvent is 1% by weight.

<img file="TW472158B_D0009.tif" />

The resulting infrared absorption filter was remarkably faded with visual hue. Figure 4 shows its spectral characteristics. As shown in Figure 4, an infrared absorption filter with a mountain-shaped characteristic with a peak at a wavelength of about 550nm in the visible light range of 400nm to 650nm can be obtained. The maximum transmittance of wavelength 800nm~1100nm is 30% or less, the transmittance of wavelength 550nm is more than 50%, and the transmittance difference of wavelength 450nm~650nm is greater than 10%. Moreover, the haze value of the easy-adhesive PET film substrate is 2.6%, which is extremely high.

In addition, the obtained infrared absorption filter was left in an atmosphere at a temperature of 60° C. and a humidity of 95% RH for 500 hours, and it was again measured that the spectral characteristics did not absorb in the infrared range. In addition, the hue changes to green.

Then, when the resulting filter is placed in front of the plasma display, the tone balance collapses and turns into a green hue.

<img file="TW472158B_D0010.tif" />

Comparative example 2

Using the infrared absorption filter manufactured in Comparative Example 1, a hard coat layer (HC) was provided on the transparent polyester film surface opposite to the infrared absorption layer of the above infrared absorption filter. The hard coating agent uses a UV-curable resin composition in which 4 parts of benzophenone are added to 100 parts of epoxy acrylic resin, and the film is formed by the bar coating method and then pre-dried at 80°C for 5 minutes. 500mJ/cm²The ultraviolet radiation will harden it. The thickness of the hard coat layer (HC) after hardening is 5 μm.

Then, a copper foil with a thickness of 9 μtm was bonded on the infrared absorption layer via a UV curable adhesive, and the bonded copper foil was patterned using a photoresist, and etching treatment was performed to form an electromagnetic wave protection layer. At this time, the line width of the copper foil is 15μm, the peak is 115μm, and the aperture ratio is 75%.

The spectral characteristics of the infrared absorption filter in which the hard coating layer, the electromagnetic wave protection layer, and the infrared absorption layer are simultaneously laminated as described above are shown in Figure 5. As shown in Figure 5, it can be seen that the infrared absorption filter is a filter that absorbs infrared and electromagnetic waves and has a slightly green hue.

Furthermore, the obtained infrared absorption filter had no infrared absorption characteristics when it was left in an atmosphere at a temperature of 60° C. and a humidity of 95% RH for 500 hours, and the spectroscopic characteristics were measured again.

Example 3

(5) Manufacturing of infrared absorption filter

Except that the composition of the coating liquid for the infrared absorption layer in Example 1 is as shown in Table 4, the coating liquid for the infrared absorption layer was prepared in the same manner as in Example 1. An infrared absorption filter coated with and dried with a coating liquid for an infrared absorption layer on the above-mentioned biaxially aligned PET film was prepared. After drying, the thickness of the coating layer is 25μm, and the amount of residual solvent is 1% by weight.

<img file="TW472158B_D0011.tif" />

The color of the infrared absorption filter is blue-gray. Figure 6 shows its spectral characteristics.

The obtained filter has a minimum transmittance of 65.0% at a wavelength of 440nm to 500nm, a minimum transmittance of 61.5% at a wavelength of 640nm to 700nm, and a maximum transmittance of 7.9% at a wavelength of 900nm to 1100nm in the near infrared range.

In addition, when the obtained filter is arranged in front of the plasma display, the color tone does not change, the controllability can be improved, and the emission of infrared rays can be reduced.

Example 4

(5) Manufacturing of infrared absorption filter

Except that the composition of the coating liquid for the infrared absorption layer in Example 1 is as shown in Table 5, the coating liquid for the infrared absorption layer was prepared in the same manner as in Example 1. An infrared absorption filter coated with and dried with a coating liquid for an infrared absorption layer on the above-mentioned biaxially aligned PET film was prepared. After drying, the thickness of the coating layer is 25μm, and the amount of residual solvent is 1% by weight.<img file="TW472158B_D0012.tif" /><img file="TW472158B_D0013.tif" />

The color of the infrared absorption filter is blue-gray. Figure 7 shows its spectral characteristics.

The obtained filter has a minimum transmittance of 62.0% at a wavelength of 440nm to 500nm, and a minimum transmittance of 62.8% at a wavelength of 640nm to 700nm. The maximum transmittance at a wavelength of 550~600nm is 59.2%, and the maximum transmittance at a wavelength of 900nm~1100nm in the near infrared range is 9.9%.

In addition, when the obtained filter is arranged in front of the plasma display, the color tone does not change, the controllability can be improved, and the emission of infrared rays can be reduced.

Reference example 1 (reference examples of examples 3 and 4)

(5) Manufacturing of infrared absorption filter

Except that the composition of the coating liquid for the infrared absorption layer in Example 1 is as shown in Table 6, the coating liquid for the infrared absorption layer was prepared in the same manner as in Example 1. An infrared absorption filter coated with and dried with a coating liquid for an infrared absorption layer on the above-mentioned biaxially aligned PET film was prepared. After drying, the thickness of the coating layer is 25μm, and the amount of residual solvent is 1% by weight.<img file="TW472158B_D0014.tif" /><img file="TW472158B_D0015.tif" />

The color of the infrared absorption filter is blue-gray. Figure 9 shows its spectral characteristics.

As shown in Figure 9, an infrared absorption filter with flat absorption in the visible light range of wavelength 400nm~650nm and strong absorption when the wavelength is above 700nm can be obtained. The transmittance difference of wavelength 450nm~650nm is less than 10%, and the wavelength is 800nm~1100nm. The maximum transmittance is below 30%, and the transmittance with a wavelength of 550nm is above 50%.

The obtained infrared absorption filter was placed in an atmosphere with a temperature of 60°C and a humidity of 95%RH for 500 hours. When the spectral characteristics were measured again, a slight color change was seen as shown in Figure 10, and the infrared absorption characteristics were maintained. The transmittance difference at wavelengths of 450nm to 650nm is 10% or less, the maximum transmittance at wavelengths of 800nm to 1100nm is 30% or less, and the transmittance at wavelengths of 550nm is more than 50%, which can maintain infrared absorption characteristics. In addition, when the filter is arranged in front of the plasma display, the color does not change, the controllability can be improved, and the emission of infrared rays can be reduced.

Reference Example 2 (Reference Example of Example 5)

(5) Manufacturing of infrared absorption filter

In Example 1, the composition of the coating liquid for the infrared absorption layer as shown in Table 6 was removed, and a copolymerized polyester resin (manufactured by Toyobo Co., Ltd., Bailong RV200, specific gravity 1.255, glass transition temperature 67°C) was used as the infrared absorption layer An infrared absorption filter was prepared in the same manner as in Example 5 except that the polymer resin was used. After drying, the thickness of the coating layer is 25μm, and the amount of residual solvent is 1% by weight.

The color of the infrared absorption filter is dark gray. Figure 11 shows its spectral characteristics. As shown in Figure 11, an infrared absorption filter with flat absorption in the visible light range of wavelength 400nm~650nm and strong absorption at wavelengths above 700nm can be obtained. The transmittance difference of wavelength 450nm~650nm is 10% or less, and wavelength 800nm~1100nm The maximum transmittance is below 30%, and the transmittance with a wavelength of 550nm is above 50%.

The obtained infrared absorption filter was left in an atmosphere at a temperature of 60°C and a humidity of 95%RH for 500 hours. When the spectral characteristics were measured again, the color tone changed to green as shown in Figure 12, and the infrared absorption characteristics were extremely poor.

Reference Example 3 (Reference Example of Example 5)

(4) Manufacturing of polymer resin for infrared absorption layer

The copolymerized polyester resin made of the dispersant of the infrared absorbing pigment was produced in the following method.

Add 136 parts by weight of dimethyl p-acid in an autoclave equipped with a thermometer and a mixer

58 parts by weight of dimethyl isocyanate

105 parts by weight of ethylene glycol

98 parts by weight of tricyclodecane dimethanol

Antimony trioxide 0.09 parts by weight

Heat at 170~220°C for 180 minutes to carry out the transesterification reaction. Then, the temperature of the reaction system was increased to 245°C, and the pressure in the system was 1.33~13.3 hPa and the reaction was continued for 180 minutes. As a result, a copolymerized polyester resin (A2) was obtained. The inherent viscosity of the copolymerized polyester resin (A2) is 0.40dl/g, the glass transition temperature is 80°C, and the specific gravity is 1.245.

Furthermore, the composition ratio of the constituent components of the copolymerized polyester resin (A2) analyzed by NMR is

Acid component

To acid 71 mol%

Iso-acid 29 mol%

Alcohol component

Ethylene glycol 49 mole%

Tricyclodecane dimethanol 51 mol%

(5) Manufacturing of infrared absorption filter

In Example 5, the composition of the coating liquid for the infrared absorption layer is shown in Table 6, and the copolymerized polyester resin (A2) was used as the polymer resin for the infrared absorption layer, and the infrared absorption layer was prepared in the same manner as in Example 5. filter. After drying, the thickness of the coating layer is 25μm, and the amount of residual solvent is 1% by weight. The difference in transmittance between 450nm and 650nm is less than 10%, the maximum transmittance between 800nm and 1100nm is less than 30%, and the transmittance between 550nm is more than 50%. The resulting infrared absorption filter had a visual hue of blue-gray. In addition, its spectral characteristics are approximately the same as those of Example 5 (Figure 9).

The obtained infrared absorption filter was placed in an atmosphere at a temperature of 60°C and a humidity of 95%RH for 500 hours. When the spectral characteristics were measured again, the color tone changed to green as shown in Fig. 13, and the infrared absorption characteristics were extremely poor.

Reference Example 4 (Reference Example of Example 5)

(4) Manufacturing of polymer resin for infrared absorption layer

The copolymerized polyester resin (A3: glass transition temperature 140° C., limiting viscosity 0.42, molecular weight Mw 45,000) described in Example 1 of JP 9-838855 A was used as the polymer resin for the infrared absorption layer.

(5) Manufacturing of infrared absorption filter

In Example 5, the composition of the coating liquid for the infrared absorption layer is shown in Table 6, and the copolymerized polyester resin (A3) is used as the polymer resin for the infrared absorption layer. The infrared absorption layer is prepared in the same manner as in Example 5. filter. The thickness of the coating layer after drying is 25m, and the amount of residual solvent is 1% by weight. The difference in transmittance between 450nm and 650nm is 10% or less, the maximum transmittance at 800nm and 1100nm is 30% or less, and the transmittance at 550nm is more than 50%. The resulting infrared absorption filter had a bluish-gray visual hue. In addition, its spectral characteristics are approximately the same as those of Example 5 (Figure 9).

Furthermore, the obtained infrared absorption filter was bent when it was left standing. The obtained infrared absorption filter was placed in an atmosphere at a temperature of 60°C and a humidity of 95%RH for 500 hours, and the infrared absorption layer was completely peeled off from the PET film of the substrate.

[Effects of the invention]

The infrared absorption filter of the present invention has large and broad absorption in the near-infrared range, high light transmittance in the visible light range, no optical defects, and no large absorption of wavelengths in a specific visible light range. In addition, it has excellent environmental stability (even if it is used for a long time under high temperature or high humidity, its spectral characteristics and color change are small). Moreover, it has good processability and productivity, and has the advantages of no curling even if it is left standing. Therefore, it is particularly suitable for optical devices such as video recorder displays, especially infrared absorption filters for plasma displays.

Fig. 1 is an explanatory diagram of the spectral characteristics of the infrared absorption filter of Example 1.

Figure 2 is an explanatory diagram of the spectral characteristics of the infrared absorption filter obtained in Example 1 after being left in an atmosphere at a temperature of 60°C and a humidity of 95% for 500 hours.

Fig. 3 is an explanatory diagram of the spectral characteristics of the infrared absorption filter of the second embodiment.

Figure 4 is an explanatory diagram of the spectral characteristics of the infrared absorption filter of Reference Example 1.

Fig. 5 is an explanatory diagram of the spectral characteristics of the infrared absorption filter of Comparative Example 2.

Fig. 6 is an explanatory diagram of the spectral characteristics of the infrared absorption filter of Example 3.

Fig. 7 is an explanatory diagram of the spectral characteristics of the infrared absorption filter of Example 4.

Fig. 8 is an explanatory diagram of the spectral characteristics of the infrared absorption filter of Reference Example 1.

Figure 9 is a graph showing the spectral characteristics of the infrared absorption filter obtained in Example 5.

Figure 10 is a graph showing the spectral characteristics of the infrared absorption filter obtained in Example 5 after being left in an atmosphere at a temperature of 60°C and a humidity of 95% for 500 hours.

Figure 11 is a graph showing the spectral characteristics of the infrared absorption filter obtained in Reference Example 2.

Figure 12 is a graph showing the spectral characteristics of the infrared absorption filter obtained in Reference Example 2 after being left in an atmosphere at a temperature of 60°C and a humidity of 95% for 500 hours.

Figure 13 is a graph showing the spectral characteristics of the infrared absorption filter obtained in Reference Example 3 after being left in an atmosphere at a temperature of 60°C and a humidity of 95% for 500 hours.