WO2013105374A1 - Narrow-region bandpass filter - Google Patents

Abstract

[Problem] To obtain an optical film which is reduced in production cost, can be produced so as to have a larger area, and has excellent durability when flexed or when used under high-temperature high-humidity conditions. [Solution] A narrow-region bandpass filter which comprises a dielectric multilayer film obtained from organic polymers.

Description

Narrow bandpass filter

The present invention relates to a narrow band-pass filter having a dielectric multilayer film containing an organic polymer.

Considering future world population growth and environmental issues, so-called agricultural industrialization that leads to stable food production by introducing high technology in agriculture has been attracting attention. In the plant factory, which is an annual production system for plants that uses high technology such as environmental control and automation, the plant cultivation environment is controlled by a computer so that crops are automatically produced without being affected by the weather and without the need for human intervention. Attempts to produce are being made. According to recent research, it has been found that plant cultivation has an optimal light source wavelength distribution for promoting growth in plant species and plant growth processes, rather than irradiating plants with white light, It is more advantageous to irradiate a specific color. For example, red light of 640 nm to 690 nm is used to promote photosynthesis, and blue light of 420 nm to 470 nm is used to promote normal formation of leaves. It is considered optimal.

More and more cases are using LEDs as artificial light sources for plant cultivation. The reason for this is that small size, light weight, low power consumption, low heat radiation, and the advantages of being able to use red LED (660 nm) and blue LED (450 nm), which are currently widely used in industry, are contributing. ing. To promote the growth of plants, using different LED light sources is certainly a unique point of view, but it is necessary to attach a large number of LED chips to the board, and a circuit system and power supply system for LED control are required. . For this reason, there is a limit to the use of the LED, and it is difficult to cope with a large-scale planting area or an outdoor greenhouse that does not require an artificial light source. Further, since the transmission wavelength range is determined by the LED material, the degree of freedom in which the light source wavelength can be arbitrarily designed in accordance with the plant species is limited.

In view of this, in the case of using a large-scale greenhouse using sunlight or an inexpensive white light source, a system that irradiates a plant with only specific light using an optical filter has been proposed. As an optical filter used for this, a so-called band-pass filter is considered effective from the above-mentioned characteristics.

Patent Document 1 discloses a narrow-band optical filter in which an inorganic material of thallium oxide and silica is laminated.

Japanese Patent No. 2001-215325

However, the filter disclosed in Patent Document 1 is a filter manufactured using a sputtering apparatus, and it is difficult to increase the area in terms of cost, and is formed of a rigid film of an inorganic material. Durability of the film when bent or at high temperature and high humidity is difficult.

Therefore, an object of the present invention is to obtain an optical film that is low in manufacturing cost, can be increased in area, and has excellent film durability when bent or at high temperature and high humidity.

The above object of the present invention is achieved by a narrow band-pass filter characterized by having a dielectric multilayer film containing an organic polymer.

It is a figure explaining the narrow-band pass band in a spectral transmittance curve. 6 is a diagram showing a spectral transmittance curve of a narrow band-pass filter of Sample 4. FIG. It is a figure which shows the spectral transmittance curve of the narrow-band band pass filter of the sample 5. FIG. It is a figure which shows the spectral transmittance curve of the narrow-band band pass filter of the sample 6. FIG. It is a figure which shows the spectral transmittance curve of the narrow-band band pass filter of the sample 9. FIG. 2 is a diagram showing a spectral transmittance curve of a narrow band-pass filter of a sample 10. FIG. It is a figure which shows the spectral transmittance curve of the narrow-band band pass filter of the sample 15. FIG.

The present invention is a narrow band-pass filter having a dielectric multilayer film containing an organic polymer. That is, the filter of the present invention is characterized in that a narrow band pass band derived from a dielectric multilayer film containing an organic polymer is formed in a spectral transmittance curve.

The effects of the present invention by using a polymer material include the following. (1) Compared with a sputtered laminated film of inorganic material, the physical durability at the time of bending of the film itself and at high temperature and high humidity is greatly improved. (2) A production method suitable for increasing the area such as melt stretching or multilayer coating is possible. For this reason, the manufacturing cost is low and the cost can be significantly reduced. (3) Since the dielectric films containing the polymer material are laminated in multiple layers, the fluctuation of the film thickness which occurs about several percent with a relative standard deviation acts on the contrary as error diffusion, and a narrow band pass band with high robustness can be formed. In addition, by using a dielectric multilayer film, it is possible to design a sharp transmission wavelength region window having a band edge that cannot be realized by a general light adjustment material such as a coloring dye or a pigment. That is, the degree of freedom in designing the transmission wavelength is high.

Hereinafter, the present invention will be described in detail.

(Narrowband passband)
In the present invention, the narrowband passband is defined as follows. In the spectral transmittance curve of FIG. 1, paying attention to a band having a top with a transmittance of 80% or more and a bottom with a transmittance of 20% or less, λ0 is an average wavelength of the wavelengths with a transmittance of 80% (that is, a transmittance of 80%). When the wavelength of the wavelength lambda ₁ and _{λ 2, λ0 = (λ 1} + λ 2) / 2 (nm)), Δλ a transmittance of 20% in the wavelength range (i.e., the wavelength of the transmittance of 20% wavelength lambda ₃ and If λ ₄ (λ ₄ > λ ₃ ), Δλ = λ ₄ −λ ₃ (nm)), a band satisfying Δλ / λ0 × 100 ≦ 15% is defined as a narrowband passband. The value of Δλ / λ0 × 100 is preferably as small as possible, preferably 10% or less, and more preferably 6% or less. In addition, since the value of Δλ / λ0 × 100 is preferably as small as possible, the value of Δλ / λ0 × 100 is preferably as small as possible, but is usually 0.5% or more.

In the present invention, the number of narrowband passbands can be set according to the purpose, and the number of narrowband passbands is not limited to one, and there may be two or more.

(Dielectric type narrow-band bandpass filter)
In general, it is known that there are three types of narrowband bandpass filters: (1) MDM type, (2) DMD type, and (3) dielectric type, where M is a metal and D is a dielectric. . The dielectric type narrow band pass band filter of the present invention belongs to the above (3), and unlike (1) and (2), a metal film having poor durability is not used in a constituent layer contributing to band formation. It is a feature.

The dielectric type narrow-band bandpass filter has at least one structure in which a high refractive index film and a low refractive index film are adjacent to each other. Here, the terms “high refractive index film” and “low refractive index film” mean that the refractive index film having the higher refractive index is the high refractive index film when the difference in refractive index between two adjacent layers is compared, and the low refractive index film is low. This means that the other refractive index film is a low refractive index film. Therefore, the terms “high refractive index film” and “low refractive index film” are the same when the refractive index films constituting the optical reflection film are focused on two adjacent refractive index films. All forms other than those having a refractive index are included.

Examples of suitable configurations included in the dielectric multilayer film of the dielectric type narrow band band-pass filter include the following.

Here, for example, (H ₁ L ₁ ) ^m means that the layer structure of H ₁ L ₁ is laminated m times and sH ₂ means that H ₂ is laminated s times.

H ₁ , H ₂ , H ₃ and H ₄ each represent a high refractive index film, and L ₁ , L ₂ , L ₃ and L ₄ represent low refractive index films. Here, H ₁ , H ₂ , H ₃ and H ₄ may be the same or different in film thickness and film configuration. Similarly, L ₁ , L ₂ , L ₃ and L ₄ may be the same or different in film thickness and film configuration. Preferably, the optical film thickness of the high refractive index film and the low refractive index film is λ / 4 ± 50% with respect to the maximum transmittance wavelength λ [nm] in the narrow band pass band of the spectral transmittance curve of the filter. Here, “λ / 4 ± 50%” means “(λ / 4−λ / 4 × 0.5) or more (λ / 4 + λ / 4 × 0.5) or less”). The relationship between the film thickness (physical film thickness) of each refractive index film and the optical film thickness in the actual laminate is optical film thickness [nm] = refractive index × physical film thickness [nm].

To form a narrow-band passband at the setting wavelength, position the lambda _{A /} 4 of lambda _A set wavelength, both high and low-index films, setting the optical thickness around this lambda _{A /} 4 do it. Preferably, the optical film thickness of each refractive index film is λ / 4 ± 50% ((λ / 4−λ / 4 × 0.5) or more (λ / 4 + λ / 4 × 0.5) or less). To design.

In the above film configurations 1 to 4, m and n are integers of 1 or more. Further, s is an integer of 2 or more, but s is generally 2. In order to adjust the width of the passband, the number of m and n may be adjusted. The smaller the m and n are, the wider the passband is. The upper limits of m and n are not particularly limited, but are usually 100 or less. The upper limit of s is not particularly limited, but is usually 10 or less.

When providing passbands in a plurality of wavelength regions, any one of the above film configurations may be provided in accordance with a set wavelength to form a laminated structure of a plurality of cavities. At this time, the film configuration of the laminated structure corresponding to each pass band may be the same or different.

Further, in order to widen the width of the stop band, the (HL) may be laminated while shifting the optical film thickness by 3 to 30% instead of repeating the same optical film thickness. These multilayer structures can be designed by using optical simulation (FTG Software Associates Film DESIGN Version 2.23.3700). When only one type of λ / 4 is used, the width of the stop band is about 30 to 100 nm, so it should be somewhat wide.

Further, it is possible to design a narrow band pass band in the blue light wavelength range of 400 nm to 500 nm or the red light wavelength range of 630 nm to 700 nm based on the above concept. These design methods are described in “Thin-Film Optical Filters Fourth Edition” Taylor and Francis Group. There are detailed descriptions in LLC 2010, pp 302-401.

Among these configurations, in the filter of the present invention, the dielectric multilayer film has the following formula (1):

It is particularly preferable to include a layer structure represented by: Here, H ₁ , H ₂ , and H ₃ are dielectric multilayer films having optical film thicknesses of (λ / 4−λ / 4 × 0.5) or more and (λ / 4 + λ / 4 × 0.5) or less. A dielectric multilayer film having a high refractive index film, wherein L ₁ and L ₂ have an optical film thickness of (λ / 4−λ / 4 × 0.5) or more and (λ / 4 + λ / 4 × 0.5) or less Where λ represents the maximum transmittance wavelength in the narrowband passband of the spectral transmittance curve of the filter. m and n are integers of 1 or more, s is an integer of 2 or more, (H ₁ L ₁ ) ^m and (L ₂ H ₃ ) ⁿ are (H ₁ L ₁ ) m times, and This means that (L ₂ H ₃ ) is repeated n times, and sH ₂ is a cavity layer. Here, the specific range and preferred range of m, n, and s are as described above. With such a configuration, durability at the time of bending and high temperature and high humidity is improved. This is thought to be due to a decrease in water and oxygen permeability due to the material type and path length of the coating film and an improvement in stress relaxation due to the mixing of materials having different elasticity and ductility. In consideration of the amount of light to be transmitted, it is preferable that the pass portion is wide to some extent. However, by using sH rather than sL, it is possible to design a band having a wide pass portion, and the end of the constituent layer is another organic film. In many cases, it is in contact with the film (for example, a film support). In that case, it is more advantageous to contact the high refractive index film than to contact the low refractive index film from the viewpoint of reducing the number of required layers.

The layer constituting the outermost surface of the filter is preferably H from the viewpoint of permeability, and more preferably rH (r is an integer of 2 or more).

In the dielectric narrow band-pass filter of the present invention, the upper limit of the total number of high refractive index films and low refractive index films is preferably 200 layers or less. More preferably, it is 100 layers or less, More preferably, it is 40 layers or less.

The preferable refractive index range of the high refractive index film is 1.70 to 2.50, more preferably 1.8 to 2.1, and still more preferably 1.90 to 2.1. The preferred refractive index range of the low refractive index film is 1.10 to 1.60, more preferably 1.30 to 1.55, and still more preferably 1.3 to 1.45. Further, a preferable refractive index difference between the high refractive index film and the low refractive index film is 0.1 or more, and more preferably 0.3 to 0.7. When the refractive index difference is in such a range, the number of layers of the dielectric multilayer film is appropriate, the productivity is improved, and the formation of the passband is stable due to being hardly affected by variations due to manufacturing variations. In addition, when it has two or more high refractive index films | membranes and low refractive index films | membranes, it is preferable that all the refractive index films satisfy | fill the requirements of the said refractive index and refractive index difference. However, this is not the case for the outermost layer and the lowermost layer. There is no upper limit to the refractive index difference, but the limit is substantially about 1.40. The refractive index difference is obtained by calculating the refractive indexes of the high refractive index film and the low refractive index film according to the following method, and the difference between the two is defined as the refractive index difference.

Each refractive index film is produced as a single film (using a base material if necessary), and after cutting this sample into 10 cm × 10 cm, the refractive index is determined according to the following method. Using a U-4000 type (manufactured by Hitachi, Ltd.) as a spectrophotometer, the surface opposite to the measurement surface (back surface) of each sample is roughened, and then light absorption is performed with a black spray. Then, the reflection of light on the back surface is prevented, and the average value is obtained by measuring 25 points of reflectance in the visible light region (400 nm to 700 nm) under the condition of regular reflection at 5 degrees, and the average refractive index is determined from the measurement result. Ask.

(Light shielding means)
In the narrow band-pass filter of the present invention, a light shielding means can be further used. By combining further light shielding means, light outside the target wavelength range can be effectively shielded, and the target wavelength range can be effectively transmitted. In this case, the light shielding means is preferably a means for shielding light in a wavelength region other than the wavelength region in which the narrow band pass band is formed, and is particularly limited as long as it is such a light shielding means. is not. Alternatively, the total light amount can be adjusted by the light shielding means. Preferably, the light shielding means is a visible light shielding layer.

Also, by providing a light shielding means, durability at the time of bending and moisture and heat resistance is improved. This is considered to be due to the fact that the stress was relieved by forming a structure in which elasticity and ductility were mixed by mixing different materials.

The light shielding means may be achieved by a dielectric multilayer film that forms a narrow band pass band in the spectral transmittance curve, or other than the dielectric multilayer film that forms a narrow band pass band, a light shielding layer (a narrow band pass band is formed). A dielectric multilayer film other than the dielectric multilayer film to be formed may be provided separately.

As the other light shielding layer, a dielectric multilayer film other than the dielectric multilayer film forming a narrow band pass band (hereinafter, also simply referred to as “other dielectric multilayer film”) can be used. As another dielectric multilayer film, a laminated structure in which a high refractive index film and a low refractive index film are repeated at the same optical film thickness, or a high refractive index film and a low refractive index film while shifting the optical film thickness by 5%, for example, A stacked structure in which layers are repeatedly stacked can be used in combination. Such a dielectric multilayer film is preferable from the viewpoint of productivity because the same material as that of the dielectric multilayer film forming the narrow band pass band can be used.

Further, as a means other than using a dielectric multilayer film, a layer containing a light absorbing / reflecting material can be provided. A light absorbing or reflecting material may be supported in the binder. Preferable binders include polyvinyl butyral resins, ethylene-vinyl acetate copolymer resins, and polyvinyl alcohol resins. Specifically, plastic polyvinyl butyral [manufactured by Sekisui Chemical Co., Ltd., Mitsubishi Monsanto, etc.], ethylene-vinyl acetate copolymer [manufactured by DuPont, manufactured by Takeda Pharmaceutical Co., Ltd., duramin], modified ethylene-vinyl acetate copolymer [Mersen G manufactured by Tosoh Corporation]. Further, as light absorption and reflection materials, tin oxide, indium oxide, zinc oxide, cadmium oxide, antimony-doped tin oxide (ATO), fluorine-doped tin oxide (FTO), tin-doped indium oxide (ITO), and aluminum-doped zinc oxide (AZO) can be preferably used, and ATO and ITO are particularly preferable. The content of the light absorbing / reflecting material is preferably 1 to 60% with respect to the total mass of the layer. The volume ratio of the light absorbing / reflecting material and the binder is preferably 1: 0.5 to 5. In addition, an ultraviolet absorber, an antioxidant, an antistatic agent, a heat stabilizer, a lubricant, a filler, a coloring agent, an adhesion adjusting agent, and the like may be appropriately added to the layer containing the light absorption / reflection material. The thickness of the layer containing the light absorbing / reflecting material is preferably 0.1 to 50 μm, and more preferably 1 to 20 μm.

(Dielectric multilayer material)
The dielectric narrow band-pass filter of the present invention includes a dielectric multilayer film containing an organic polymer. The organic polymer contained in the dielectric multilayer film is not particularly limited, and is not particularly limited as long as the polymer can form the dielectric multilayer film.

For example, as the organic polymer, organic polymers described in JP-T-2002-509279 can be used. Specific examples include polyethylene naphthalate (PEN) and its isomers (eg, 2,6-, 1,4-, 1,5-, 2,7- and 2,3-PEN), polyalkylene terephthalates (eg, , Polyethylene terephthalate, polybutylene terephthalate, and poly-1,4-cyclohexanedimethylene terephthalate), polyimide (eg, polyacrylimide), polyetherimide, atactic polystyrene, polycarbonate, polyalkyl methacrylate (eg, polyisobutyl methacrylate, Polypropyl methacrylate, polyethyl methacrylate, and polymethyl methacrylate), polyalkyl acrylates (eg, polybutyl acrylate, and polymethyl acrylate), cellulose derivatives (eg, , Ethylcellulose, acetylcellulose, cellulose propionate, acetylcellulose butyrate, and cellulose nitrate), polyalkylene polymers (eg, polyethylene, polypropylene, polybutylene, polyisobutylene, and poly (4-methyl) pentene), fluorinated polymers ( For example, perfluoroalkoxy resins, polytetrafluoroethylene, fluorinated ethylene propylene copolymers, polyvinylidene fluoride, and polychlorotrifluoroethylene), chlorinated polymers (eg, polyvinylidene chloride and polyvinyl chloride), polysulfones, polyether sulfones , Polyacrylonitrile, polyamide, silicone resin, epoxy resin, polyvinyl acetate, polyether amide, ionomer resin, elastomer For example, polybutadiene, polyisoprene and neoprene), and polyurethanes. Copolymers such as copolymers of PEN [e.g. (a) terephthalic acid or ester thereof, (b) isophthalic acid or ester thereof, (c) phthalic acid or ester thereof, (d) alkane glycol, (e) cycloalkane glycol ( (E.g., cyclohexanedimethanoldiol), (f) alkanedicarboxylic acid, and / or (g) cycloalkanedicarboxylic acid (e.g., cyclohexanedicarboxylic acid) and 2,6-, 1,4-, 1,5-, 2, 7- and / or copolymers with 2,3-naphthalenedicarboxylic acid or esters thereof], copolymers of polyalkylene terephthalates [eg (a) naphthalenedicarboxylic acid or esters thereof, (b) isophthalic acid or esters thereof, ( c) phthalic acid or The ester, (d) alkane glycol, (e) cycloalkane glycol (eg, cyclohexanedimethanol diol), (f) alkane dicarboxylic acid, and / or (g) cycloalkane dicarboxylic acid (eg, cyclohexanedicarboxylic acid); Also suitable are copolymers with terephthalic acid or esters thereof, and styrene copolymers (eg styrene-butadiene copolymers and styrene-acrylonitrile copolymers), 4,4-bibenzoic acid and ethylene glycol. In addition, each layer may each include a blend of two or more of the above polymers or copolymers (eg, a blend of SPS and atactic polystyrene).

As described in US Pat. No. 6,049,419, a dielectric multilayer film can be formed by subjecting the polymer to melt extrusion and stretching. In the present invention, a preferred combination of polymers forming the high refractive index film and the low refractive index film includes PEN / PMMA, PEN / polyvinylidene fluoride, and PEN / PET.

Further, as the organic polymer, a polymer described in JP 2010-184493 may be used. Specifically, a polyester (hereinafter referred to as polyester A) and a polyester (hereinafter referred to as polyester B) containing residues derived from at least three diols of ethylene glycol, spiroglycol and butylene glycol, Can be used. Polyester A is not particularly limited as long as it has a structure obtained by polycondensation of a dicarboxylic acid component and a diol component. For example, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, Examples thereof include poly-1,4-cyclohexanedimethylene terephthalate and polyethylene diphenylate. Polyester A may be a copolymer. Here, the copolyester has a structure obtained by polycondensation using at least three or more dicarboxylic acid components and diol components. Examples of the dicarboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, Examples thereof include 4′-diphenylsulfone dicarboxylic acid, adipic acid, sebacic acid, dimer acid, cyclohexanedicarboxylic acid and ester-forming derivatives thereof. Examples of the glycol component include ethylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentadiol, diethylene glycol, polyalkylene glycol, 2,2-bis (4 ′ -Β-hydroxyethoxyphenyl) propane, isosorbate, 1,4-cyclohexanedimethanol, spiroglycol, and ester-forming derivatives thereof. Polyester A is preferably polyethylene terephthalate or polyethylene naphthalate.

The polyester B includes residues derived from at least three kinds of diols, ethylene glycol, spiroglycol and butylene glycol. Typical examples include copolymerized polyesters having a structure obtained by copolymerization using ethylene glycol, spiroglycol and butylene glycol, and polyesters having a structure obtained by polymerization using these three diols. There is polyester obtained by blending. This configuration is preferable because it is easy to form and difficult to delaminate. Moreover, it is preferable that the polyester B is a polyester containing residues derived from at least two dicarboxylic acids of terephthalic acid / cyclohexanedicarboxylic acid. Such polyesters include copolyesters copolymerized with terephthalic acid / cyclohexanedicarboxylic acid, or those obtained by blending polyesters containing terephthalic acid residues and polyesters containing cyclohexanedicarboxylic acid residues. The polyester containing the cyclohexanedicarboxylic acid residue has a large difference between the in-plane average refractive index of the A layer and the in-plane average refractive index of the B layer, and a high reflectance is obtained. Moreover, since the glass transition temperature difference with polyethylene terephthalate or polyethylene naphthalate is small, it is difficult to be overstretched at the time of molding, and it is preferable that delamination is difficult.

In addition, it is also preferable to use a water-soluble polymer as the polymer. The water-soluble polymer is preferable because it does not use an organic solvent, has a low environmental load, and has high flexibility, so that the durability of the film during bending is improved. Examples of the water-soluble polymer include polyvinyl alcohols, polyvinyl pyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymer, potassium acrylate-acrylonitrile copolymer, vinyl acetate-acrylic ester copolymer, Or acrylic resin such as acrylic acid-acrylic acid ester copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid ester copolymer, styrene-α-methylstyrene -Styrene acrylic resin such as acrylic acid copolymer or styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer, styrene-sodium styrenesulfonate copolymer, styrene-2-hydroxyethyl acrylate copolymer Coalescence, styrene-2 -Hydroxyethyl acrylate-potassium styrene sulfonate copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinyl naphthalene-acrylic acid copolymer, vinyl naphthalene-maleic acid copolymer, vinyl acetate -Synthetic water-soluble polymers such as maleic acid ester copolymers, vinyl acetate-crotonic acid copolymers, vinyl acetate copolymers such as vinyl acetate-acrylic acid copolymers and their salts; gelatin, thickened And natural water-soluble polymers such as saccharides. Among these, particularly preferred examples include polyvinyl alcohol, polyvinylpyrrolidones and copolymers containing them, gelatin, thickening polysaccharides (particularly celluloses) from the viewpoint of handling during production and film flexibility. Is mentioned. These water-soluble polymers may be used alone or in combination of two or more.

Preferred polyvinyl alcohol includes modified polyvinyl alcohol in addition to ordinary polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate. Examples of the modified polyvinyl alcohol include cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, nonion-modified polyvinyl alcohol, and vinyl alcohol polymers.

The polyvinyl alcohol obtained by hydrolyzing vinyl acetate preferably has an average degree of polymerization of 1,000 or more, and particularly preferably has an average degree of polymerization of 1,500 to 5,000. The degree of saponification is preferably 70 to 100 mol%, particularly preferably 80 to 99.5 mol%.

Examples of the cation-modified polyvinyl alcohol have primary to tertiary amino groups and quaternary ammonium groups in the main chain or side chain of the polyvinyl alcohol as described in JP-A-61-10383. Polyvinyl alcohol, which is obtained by saponifying a copolymer of an ethylenically unsaturated monomer having a cationic group and vinyl acetate.

Examples of the ethylenically unsaturated monomer having a cationic group include trimethyl- (2-acrylamido-2,2-dimethylethyl) ammonium chloride and trimethyl- (3-acrylamido-3,3-dimethylpropyl) ammonium chloride. N-vinylimidazole, N-vinyl-2-methylimidazole, N- (3-dimethylaminopropyl) methacrylamide, hydroxylethyltrimethylammonium chloride, trimethyl- (2-methacrylamidopropyl) ammonium chloride, N- (1, And 1-dimethyl-3-dimethylaminopropyl) acrylamide. The ratio of the cation-modified group-containing monomer in the cation-modified polyvinyl alcohol is 0.1 to 10 mol%, preferably 0.2 to 5 mol%, relative to vinyl acetate.

Anion-modified polyvinyl alcohol is, for example, polyvinyl alcohol having an anionic group as described in JP-A-1-206088, as described in JP-A-61-237681 and JP-A-63-307979, Examples thereof include a copolymer of vinyl alcohol and a vinyl compound having a water-soluble group, and modified polyvinyl alcohol having a water-soluble group as described in JP-A-7-285265.

Nonionic modified polyvinyl alcohols include, for example, polyvinyl alcohol derivatives obtained by adding a polyalkylene oxide group to a part of vinyl alcohol as described in JP-A-7-9758, and described in JP-A-8-25795. Block copolymer of vinyl compound having hydrophobic group and vinyl alcohol, silanol modified polyvinyl alcohol having silanol group, reactive group modified polyvinyl alcohol having reactive group such as acetoacetyl group, carbonyl group, carboxyl group Etc. Examples of the vinyl alcohol polymer include Exeval (trade name: manufactured by Kuraray Co., Ltd.) and Nichigo G polymer (trade name: manufactured by Nippon Synthetic Chemical Industry Co., Ltd.). Polyvinyl alcohol can be used in combination of two or more, such as the degree of polymerization and the type of modification.

As the gelatin, in addition to lime-processed gelatin, acid-processed gelatin may be used, and gelatin hydrolyzate and gelatin enzyme-decomposed product can also be used.

Examples of thickening polysaccharides include natural simple polysaccharides, natural complex polysaccharides, synthetic simple polysaccharides and synthetic complex polysaccharides that are generally known. Reference can be made to the encyclopedia (2nd edition), Tokyo Kagaku Doujin Publishing, “Food Industry”, Vol. 31 (1988), p. 21.

The thickening polysaccharide as used herein is a polymer of saccharides and has many hydrogen bonding groups in the molecule. Due to the difference in hydrogen bonding strength between molecules depending on the temperature, the viscosity at low temperature and the viscosity at high temperature are It is a polysaccharide with a large viscosity difference, and when metal oxide fine particles are added, the viscosity rises due to hydrogen bonding with the metal oxide fine particles at low temperatures. , A polysaccharide that causes an increase in viscosity at 40 ° C. of 1.0 mPa · s or more when added, preferably 5.0 mPa · s or more, and more preferably 10.0 mPa · s or more. It is a provided polysaccharide.

Examples of the thickening polysaccharide include β1-4 glucan (eg, carboxymethylcellulose, carboxyethylcellulose, etc.), galactan (eg, agarose, agaropectin, etc.), galactomannoglycan (eg, locust bean gum, guaran, etc.), xylo Glucan (eg, tamarind gum, etc.), glucomannoglycan (eg, salmon mannan, wood-derived glucomannan, xanthan gum, etc.), galactoglucomannoglycan (eg, softwood-derived glycan), arabinogalactoglycan (eg, soybean) Glycans derived from microorganisms, glycans derived from microorganisms, etc.), glucoraminoglycans (eg, gellan gum, etc.), glycosaminoglycans (eg, hyaluronic acid, keratan sulfate, etc.), alginic acid and alginates, agar, κ-carrageenan, Examples thereof include natural polymer polysaccharides derived from red algae such as λ-carrageenan, ι-carrageenan, and far cerulean. In particular, when metal oxide particles are contained as described later, from the viewpoint of not reducing the dispersion stability of the metal oxide fine particles, it is preferable that the structural unit does not have a carboxylic acid group or a sulfonic acid group. Such polysaccharides include, for example, pentoses such as L-arabitose, D-ribose, 2-deoxyribose, and D-xylose, and hexoses such as D-glucose, D-fructose, D-mannose, and D-galactose only. It is preferable that it is a polysaccharide. Specifically, tamarind seed gum known as xyloglucan whose main chain is glucose and side chain is xylose, guar gum known as galactomannan whose main chain is mannose and side chain is galactose, locust bean gum, Tara gum or arabinogalactan whose main chain is galactose and whose side chain is arabinose can be preferably used.

Two or more thickening polysaccharides may be used in combination.

The weight average molecular weight of the water-soluble polymer is preferably 1,000 or more and 200,000 or less. Furthermore, 3,000 or more and 40,000 or less are more preferable. In this specification, the value measured on the following measurement conditions using gel permeation chromatography (GPC) is employ | adopted for a weight average molecular weight.

In the present invention, a curing agent may be used to cure the water-soluble polymer as a binder.

The curing agent is not particularly limited as long as it causes a curing reaction with the water-soluble polymer, but boric acid and its salt are preferable when the water-soluble polymer is polyvinyl alcohol. As the curing agent, other known ones can be used. Generally, the curing agent is a compound having a group capable of reacting with a water-soluble polymer or a compound that promotes the reaction between different groups of the water-soluble polymer. Depending on the type of water-soluble polymer, it is appropriately selected and used. Specific examples of the curing agent include, for example, epoxy curing agents (diglycidyl ethyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-diglycidyl cyclohexane, N, N-diglycidyl- 4-glycidyloxyaniline, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, etc.), aldehyde curing agents (formaldehyde, glioxal, etc.), active halogen curing agents (2,4-dichloro-4-hydroxy-1,3,5) -S-triazine, etc.), active vinyl compounds (1,3,5-tris-acryloyl-hexahydro-s-triazine, bisvinylsulfonylmethyl ether, etc.), aluminum alum and the like.

When the water-soluble polymer is gelatin, for example, organic hardeners such as vinylsulfone compounds, urea-formalin condensates, melanin-formalin condensates, epoxy compounds, aziridine compounds, active olefins, isocyanate compounds, etc. Inorganic polyvalent metal salts such as chromium, aluminum and zirconium.

From the viewpoint of forming a laminated film, the content of the organic polymer is preferably 10% by mass or more, and preferably 25% by mass or more with respect to the total mass of the refractive index film (the upper limit is 100% by mass). ).

(Metal oxide particles)
The dielectric multilayer film forming the narrow band pass band preferably further contains metal oxide particles. By containing metal oxide particles, the refractive index difference between the refractive index films can be increased, the number of stacked layers can be reduced, and a thin film can be obtained. In addition, there is an advantage that stress relaxation works and film physical properties (flexibility at the time of bending and high temperature and high humidity) are improved. The metal oxide particles may be contained in any of the films constituting the dielectric multilayer film, but a preferable form is that at least the high refractive index film contains metal oxide particles, and a more preferable form is a high refractive index. Both the film and the low refractive index film have a form containing metal oxide particles.

Examples of the metal oxide particles include titanium dioxide, zirconium oxide, zinc oxide, silicon dioxide (synthetic amorphous silica, colloidal silica), alumina, colloidal alumina, lead titanate, red lead, yellow lead, zinc yellow, oxidation Examples thereof include chromium, ferric oxide, iron black, copper oxide, magnesium oxide, magnesium hydroxide, strontium titanate, yttrium oxide, niobium oxide, europium oxide, lanthanum oxide, zircon, and tin oxide.

The metal oxide particles have an average particle size of 100 nm or less, preferably 4 to 50 nm, more preferably 4 to 30 nm. The average particle size of the metal oxide particles is determined by observing the particles themselves or the particles appearing on the cross section or surface of the layer with an electron microscope and measuring the particle size of 1,000 arbitrary particles. Average). Here, the particle diameter of each particle is represented by a diameter assuming a circle equal to the projected area.

The content of metal oxide particles in each refractive index film is preferably 20 to 90% by mass, and more preferably 40 to 75% by mass with respect to the total mass of the refractive index film.

As the metal oxide particles, it is preferable to use solid fine particles selected from titanium dioxide, silicon dioxide, and alumina.

In the low refractive index film, it is preferable to use silicon dioxide (silica) as the metal oxide particles, and it is particularly preferable to use acidic colloidal silica sol.

[Silicon dioxide]
As silicon dioxide (silica) that can be used in the present invention, silica synthesized by an ordinary wet method, colloidal silica, silica synthesized by a gas phase method, or the like is preferably used, but is particularly preferably used in the present invention. As the fine particle silica, colloidal silica or fine particle silica synthesized by a vapor phase method is preferable.

The metal oxide particles are preferably in a state where the fine particle dispersion before mixing with the cationic polymer is dispersed to the primary particles.

For example, in the case of the gas phase method fine particle silica, the average particle size (particle size in the dispersion state before coating) of the metal oxide fine particles dispersed in the primary particle state is 100 nm or less. More preferably, it is 4 to 50 nm, and most preferably 4 to 20 nm.

For example, Aerosil manufactured by Nippon Aerosil Co., Ltd. is commercially available as the silica synthesized by the vapor phase method in which the average particle diameter of primary particles is 4 to 20 nm. The vapor phase fine particle silica can be dispersed to primary particles relatively easily by being sucked and dispersed in water, for example, by a jet stream inductor mixer manufactured by Mitamura Riken Kogyo Co., Ltd.

As the gas phase process silica, various types of Aerosil manufactured by Nippon Aerosil Co., Ltd. are currently available.

The colloidal silica preferably used in the present invention is obtained by heating and aging a silica sol obtained by metathesis with an acid of sodium silicate or the like and passing through an ion exchange resin layer. For example, Japanese Patent Laid-Open Nos. 57-14091, 60-219083, 60-219084, 61-20792, 61-188183, 61-188183, 63-17807, JP 4-93284, JP 5-278324, JP 6-92011, JP 6-183134, JP 6-297830, JP 7-7. 81214, JP-A-7-101142, JP-A-7-179029, JP-A-7-137431, and International Publication No. 94/26530 pamphlet. Such colloidal silica may be a synthetic product or a commercially available product. Commercially available products include the Snowtex series (Snowtex 20, Snowtex 30, Snowtex 40, Snowtex O, Snowtex OS, Snowtex OXS, Snowtex XS, Snowtex sold by Nissan Chemical Industries, Ltd. O-40, Snowtex C, Snowtex N, Snowtex S, Snowtex 20L, Snowtex OL).

The preferred average particle size (number average; diameter) of colloidal silica is usually 5 to 100 nm, but an average particle size of 7 to 30 nm is particularly preferable.

Silica and colloidal silica synthesized by a vapor phase method may be those whose surfaces are cation-modified, or those treated with Al, Ca, Mg, Ba, or the like.

As the metal oxide contained in the high refractive index film, TiO ₂ , ZnO, and ZrO ₂ are preferable, and TiO ₂ is used from the viewpoint of the stability of the metal oxide particle-containing composition described later for forming the high refractive index film. Is more preferable, and titanium dioxide sol is more preferable. Of TiO ₂ , rutile type is more preferable than anatase type because it has low catalytic activity, and thus the weather resistance of the high refractive index film and the adjacent layer is high, and the refractive index is high.

〔titanium dioxide〕
Hereinafter, a suitable method for producing the titanium dioxide sol will be described.

The first step in the production method of rutile type fine particle titanium dioxide includes at least one basic compound selected from the group consisting of an alkali metal hydroxide and an alkaline earth metal hydroxide. It is the process (process 1) processed by this.

Titanium dioxide hydrate can be obtained by hydrolysis of water-soluble titanium compounds such as titanium sulfate and titanium chloride. The method of hydrolysis is not particularly limited, and a known method can be applied. Especially, it is preferable that it was obtained by thermal hydrolysis of titanium sulfate.

The step (1) can be performed, for example, by adding the basic compound to an aqueous suspension of the titanium dioxide hydrate and treating (reacting) it under a predetermined temperature condition for a predetermined time. it can.

The method for preparing the titanium dioxide hydrate as an aqueous suspension is not particularly limited, and can be performed by adding the titanium dioxide hydrate to water and stirring. The concentration of the suspension is not particularly limited. For example, it is preferable that the concentration of TiO ₂ is 30 to 150 g / L in the suspension. By setting it within the above range, the reaction (treatment) can proceed efficiently.

The at least one basic compound selected from the group consisting of alkali metal hydroxides and alkaline earth metal hydroxides used in the step (1) is not particularly limited. Examples include potassium, magnesium hydroxide, calcium hydroxide, and the like. The amount of the basic compound added in the step (1) is preferably 30 to 300 g / L in terms of the basic compound concentration in the reaction (treatment) suspension.

The above step (1) is preferably performed at a reaction (treatment) temperature of 60 to 120 ° C. The reaction (treatment) time varies depending on the reaction (treatment) temperature, but is preferably 2 to 10 hours. The reaction (treatment) is preferably performed by adding an aqueous solution of sodium hydroxide, potassium hydroxide, magnesium hydroxide, or calcium hydroxide to a suspension of titanium dioxide hydrate. After the reaction (treatment), the reaction (treatment) mixture is cooled, neutralized with an inorganic acid such as hydrochloric acid as necessary, and then filtered and washed with water to obtain fine particle titanium dioxide hydrate.

Further, as the second step (step (2)), the compound obtained in step (1) may be treated with a carboxylic acid group-containing compound and an inorganic acid. The method of treating the compound obtained in the above step (1) with an inorganic acid in the production of rutile type fine particle titanium dioxide is a known method, but in addition to the inorganic acid, a carboxylic acid group-containing compound is used. Can be adjusted.

The carboxylic acid group-containing compound is an organic compound having a —COOH group. The carboxylic acid group-containing compound is preferably a polycarboxylic acid having 2 or more, more preferably 2 or more and 4 or less carboxylic acid groups. Since the polycarboxylic acid has a coordination ability to a metal atom, it is presumed that agglomeration between fine particles can be suppressed by coordination, whereby rutile type fine particle titanium dioxide can be suitably obtained.

The carboxylic acid group-containing compound is not particularly limited, and examples thereof include dicarboxylic acids such as succinic acid, malonic acid, succinic acid, glutaric acid, adipic acid, propylmalonic acid, and maleic acid; hydroxys such as malic acid, tartaric acid, and citric acid. Polycarboxylic acids; aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, hemimellitic acid and trimellitic acid; ethylenediaminetetraacetic acid and the like. Among these, two or more compounds may be used in combination.

Note that all or part of the carboxylic acid group-containing compound may be a neutralized product of an organic compound having a —COOH group (for example, an organic compound having a —COONa group or the like).

The inorganic acid is not particularly limited, and examples thereof include hydrochloric acid, sulfuric acid, nitric acid and the like. The inorganic acid may be added so that the concentration in the reaction (treatment) solution is 0.5 to 2.5 mol / L, more preferably 0.8 to 1.4 mol / L.

The step (2) is preferably performed by suspending the compound obtained in the step (1) in pure water and heating it with stirring as necessary. The carboxylic acid group-containing compound and the inorganic acid may be added simultaneously or sequentially, but it is preferable to add them sequentially.

The addition may be to add an inorganic acid after the addition of the carboxylic acid group-containing compound, or to add the carboxylic acid group-containing compound after the addition of the inorganic acid.

For example, a carboxyl group-containing compound is added to the suspension of the compound obtained by the above step (1), heating is started, and the inorganic acid is added when the liquid temperature is 60 ° C. or higher, preferably 90 ° C. or higher. Adding and maintaining the liquid temperature, preferably stirring for 15 minutes to 5 hours, more preferably 2 to 3 hours (Method 1); heating the suspension of the compound obtained by the above step (1) In addition, an inorganic acid is added when the liquid temperature is 60 ° C. or higher, preferably 90 ° C. or higher, and a carboxylic acid group-containing compound is added 10 to 15 minutes after the inorganic acid addition, and the liquid temperature is preferably maintained. And a method of stirring for 15 minutes to 5 hours, more preferably 2 to 3 hours (Method 2). By carrying out these methods, a suitable fine particle rutile type titanium dioxide can be obtained.

When the step (2) is performed by the method 1, the carboxylic acid group-containing compound is preferably used in an amount of 0.25 to 1.5 mol% with respect to 100 mol% of TiO ₂ , and 0.4 to More preferably, it is used at a ratio of 0.8 mol%. When the addition amount of the carboxylic acid group-containing compound is less than 0.25 mol%, there is a possibility that particle growth proceeds and particles having the target particle size may not be obtained. When the amount is more than 5 mol%, rutile conversion of the particles does not proceed and anatase particles may be formed.

When the step (2) is performed by the method 2, the carboxylic acid group-containing compound is preferably used in an amount of 1.6 to 4.0 mol% with respect to 100 mol% of TiO ₂ , and is preferably 2.0 to It is more preferable to use it at a ratio of 2.4 mol%.

When the addition amount of the carboxylic acid group-containing compound is less than 1.6 mol%, there is a possibility that the particle growth proceeds and particles having the target particle size may not be obtained, and the addition amount of the carboxylic acid group-containing compound is 4. If the amount is more than 0 mol%, the rutile conversion of the particles may not proceed and anatase particles may be formed. Even if the amount of the carboxylic acid group-containing compound exceeds 4.0 mol%, the effect will be good. It is economically disadvantageous. Further, if the addition of the carboxylic acid group-containing compound is performed in less than 10 minutes after the addition of the inorganic acid, there is a possibility that the rutileization will not proceed and anatase-type particles may be formed. In some cases, the particle growth proceeds excessively, and particles having a target particle size cannot be obtained.

In the above step (2), it is preferable to cool after completion of the reaction (treatment) and further neutralize to pH 5.0 to 10.0. The neutralization can be performed with an alkaline compound such as an aqueous sodium hydroxide solution or aqueous ammonia. The target rutile type fine particle titanium dioxide can be separated by filtering and washing with water after neutralization.

In addition, as other methods for producing titanium dioxide fine particles, known methods described in “Titanium oxide—physical properties and applied technology” (Kagino Kiyono, pp 255-258 (2000) Gihodo Publishing Co., Ltd.) can be used.

Furthermore, another method for producing metal oxide particles including titanium oxide particles is disclosed in JP-A-2000-053421 (comprising alkyl silicate as a dispersion stabilizer, and silicon in the alkyl silicate is changed to SiO _2. A titanium oxide sol having a weight ratio (SiO ₂ / TiO ₂ ) of 0.7 to 10 of the amount converted to TiO ₂ and the amount converted to TiO ₂ in titanium oxide), JP 2000-063119 A (TiO ₂ Reference can be made to matters described in, for example, a sol in which a composite colloidal particle of —ZrO ₂ —SnO ₂ is used as a nucleus and a surface thereof is coated with a composite oxide colloidal particle of WO ₃ —SnO ₂ —SiO ₂ .

Further, the titanium oxide particles may be coated with a silicon-containing hydrated oxide. The coating amount of the silicon-containing hydrated compound is 3 to 30% by mass, preferably 3 to 10% by mass, more preferably 3 to 8% by mass. This is because if the coating amount is 30% by mass or less, a desired refractive index of the high refractive index film can be obtained, and if the coating amount is 3% or more, particles can be stably formed.

As a method of coating titanium oxide particles with a silicon-containing hydrated oxide, it can be produced by a conventionally known method. For example, JP-A-10-158015 (Si / Al hydration to rutile titanium oxide) Oxide treatment; a method for producing a titanium oxide sol in which a hydrous oxide of silicon and / or aluminum is deposited on the surface of titanium oxide after peptization in the alkaline region of the titanate cake), JP 2000-204301 A (A sol in which a rutile-type titanium oxide is coated with a complex oxide of Si and Zr and / or Al. Hydrothermal treatment), JP 2007-246351 (Oxidation obtained by peptizing hydrous titanium oxide) titanium to hydrosol, wherein ^R _{1 n SiX 4-n} (wherein ^{R 1} as stabilizer _C 1 -C ₈ alkyl group, glycidyloxy substituted _C 1 -C ₈ Alkyl group or a C ₂ -C ₈ alkenyl group, X is an alkoxy group, n is 1 or 2. Sodium silicate added in the alkaline range the compound having a complexing effect on organoalkoxysilanes or titanium oxide) Alternatively, it is possible to refer to matters described in, for example, a method for producing a titanium oxide hydrosol coated with a hydrous oxide of silicon by adding, adjusting pH, and aging a silica sol solution. In addition, a titanium oxide sol stabilized at a pH in an acidic range obtained by peptizing a titanium oxide such as hydrous titanium oxide with a monobasic acid or a salt thereof, and an alkyl silicate as a dispersion stabilizer are mixed by a conventional method. Neutralization method (Japanese Patent Laid-Open No. 2000-053421); while maintaining hydrogen peroxide and metal tin at a H ₂ O ₂ / Sn molar ratio of 2 to 3 simultaneously or alternately with titanium salts (eg, titanium tetrachloride) ) And the like to form a basic salt aqueous solution containing titanium, and the basic salt aqueous solution is maintained at a temperature of 50 to 100 ° C. for 0.1 to 100 hours to contain a composite containing titanium oxide. Colloidal aggregates are formed, and then the electrolyte in the aggregate slurry is removed to produce a stable aqueous sol of composite colloidal particles comprising titanium oxide; silicates (e.g., sodium silicate A stable aqueous sol of composite colloidal particles containing silicon dioxide is produced by preparing an aqueous solution containing the aqueous solution) and removing the cations present in the aqueous solution; the resulting composite containing titanium oxide 100 parts by weight of the aqueous sol in terms of metal oxide TiO ₂ and ₂ to 100 parts by weight of the resulting composite aqueous sol containing silicon dioxide in terms of metal oxide SiO ₂ were mixed together. A method of heating and aging at 80 ° C. for 1 hour after removing ions (Japanese Patent Laid-Open No. 2000-063119); adding hydroperoxide to hydrous titanic acid gel or sol to dissolve hydrous titanic acid, and obtaining peroxotitanic acid A silicon compound or the like is added to the aqueous solution and heated to obtain a dispersion of core particles composed of a complex solid solution oxide having a rutile structure, and then the silicon compound or the like is added to the dispersion of the core particles. After heating to form a coating layer on the core particle surface, thereby to obtain a sol of composite oxide particles are dispersed, further, it includes a method of heating.

The volume average particle diameter of the titanium oxide particles is preferably 30 nm or less, more preferably 1 to 30 nm, and even more preferably 5 to 15 nm. A volume average particle size of 30 nm or less is preferable from the viewpoint of low haze and excellent visible light transmittance.

Here, the volume average particle diameter is a volume average particle diameter of primary particles or secondary particles dispersed in a medium, and can be measured by a laser diffraction / scattering method, a dynamic light scattering method, or the like.

Specifically, the particles themselves or the particles appearing on the cross section or surface of the refractive index film are observed with an electron microscope, and the particle diameters of 1,000 arbitrary particles are measured, and d1, d2,. .. In a group of metal oxide particles having n1, n2,..., Nk particles each having a particle size of dk, the volume average particle size when the volume per particle is vi The average particle diameter weighted by the volume represented by mv = {Σ (vi · di)} / {Σ (vi)} is calculated.

In the present invention, colloidal silica composite emulsion can also be used as a metal oxide in the low refractive index film. The colloidal silica composite emulsion preferably used in the present invention has a central part of a particle mainly composed of a polymer or copolymer, and is described in JP-A-59-71316 and JP-A-60-127371. It is obtained by polymerizing a monomer having an ethylenically unsaturated bond in the presence of colloidal silica which has been conventionally known by an emulsion polymerization method. The particle diameter of colloidal silica applied to the composite emulsion is preferably less than 40 nm.

The colloidal silica used for the preparation of this composite emulsion usually includes primary particles of 2 to 100 nm. Examples of the ethylenic monomer include (meth) acrylic acid ester having 1 to 18 carbon atoms, aryl group, or allyl group, styrene, α-methylstyrene, vinyl toluene, acrylonitrile, vinyl chloride, vinylidene chloride. , Vinyl acetate, vinyl propionate, acrylamide, N-methylol acrylamide, ethylene, butadiene, and other materials known in the latex industry, and if necessary, vinyl trimethoate is used to improve compatibility with colloidal silica. Vinyl silanes such as oxysilane, vinyltriethoxysilane, γ-methacrylooxypropyltrimethoxysilane, etc. are also used to stabilize the dispersion of (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid. Anionic monomers such as -Is used as an auxiliary agent. In addition, two or more types of ethylenic monomers can be used together as necessary.

Further, the ratio of ethylenic monomer / colloidal silica in the emulsion polymerization is preferably 100/1 to 200 in terms of solid content.

Among the colloidal silica composite emulsions used in the present invention, those having a glass transition point in the range of −30 to 30 ° C. are preferable.

In addition, preferred examples of the composition include ethylenic monomers such as acrylic acid esters and methacrylic acid esters, and particularly preferred are copolymers of (meth) acrylic acid esters and styrene, alkyl (meth) acrylates. Examples thereof include a copolymer of ester and (meth) acrylic acid aralkyl ester, and a (meth) acrylic acid alkyl ester and (meth) acrylic acid aryl ester copolymer.

Examples of emulsifiers used in emulsion polymerization include alkyl allyl polyether sulfonic acid soda salt, lauryl sulfonic acid soda salt, alkyl benzene sulfonic acid soda salt, polyoxyethylene nonylphenyl ether sodium nitrate salt, alkyl allyl sulfosuccinate soda salt, sulfo Examples include propyl maleic acid monoalkyl ester soda salt.

(Other additives)
Each refractive index film forming the dielectric multilayer film can contain various additives as required.

Specifically, various anionic, cationic or nonionic surfactants; dispersants such as polycarboxylic acid ammonium salt, allyl ether copolymer, benzenesulfonic acid sodium salt, graft compound dispersant, polyethylene glycol type nonionic dispersant; Organic acid salts such as acetate, propionate or citrate; organic ester plasticizers such as monobasic organic acid esters and polybasic organic acid esters, organic phosphate plasticizers, organic phosphorous acid plasticizers, etc. Plasticizers such as phosphoric acid plasticizers; ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988, and JP-A-62-261476, JP-A-57-74192, JP-A-57 -87989, 60-72785, 61-14659, JP-A-1-95091 and 3-13376, etc .; Japanese Patent Laid-Open Nos. 59-42993, 59-52689, 62-280069, 61-242871, and Japanese Patent Laid-Open No. 4-219266 Optical brighteners described in the Gazettes, etc .; pH adjusters such as sulfuric acid, phosphoric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate; antifoaming agents; lubricants such as diethylene glycol; Agents; antistatic agents; may contain various known additives such as matting agents.

(Film support (base material))
In the present invention, the above-mentioned dielectric multilayer film can be laminated on a film support if necessary. As the film support used in the present invention, various resin films can be used, such as polyolefin films (polyethylene, polypropylene, etc.), polyester films (polyethylene terephthalate, polyethylene naphthalate, etc.), polyvinyl chloride, cellulose acetate, etc. Can be used, and a polyester film is preferable. Although it does not specifically limit as a polyester film (henceforth polyester), It is preferable that it is polyester which has the film formation property which has a dicarboxylic acid component and a diol component as main structural components. The main component dicarboxylic acid component includes terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenylethanedicarboxylic acid, Examples thereof include cyclohexane dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl thioether dicarboxylic acid, diphenyl ketone dicarboxylic acid, and phenylindane dicarboxylic acid. Examples of the diol component include ethylene glycol, propylene glycol, tetramethylene glycol, cyclohexanedimethanol, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyethoxyphenyl) propane, bis ( 4-Hydroxyphenyl) sulfone, bisphenol fluorene hydroxyethyl ether, diethylene glycol, neopentyl glycol, hydroquinone, cyclohexanediol and the like. Among the polyesters having these as main components, from the viewpoints of transparency, mechanical strength, dimensional stability, etc., dicarboxylic acid components such as terephthalic acid, 2,6-naphthalenedicarboxylic acid, diol components such as ethylene glycol and 1 Polyester having 1,4-cyclohexanedimethanol as the main constituent is preferred. Among these, polyesters mainly composed of polyethylene terephthalate and polyethylene naphthalate, copolymerized polyesters composed of terephthalic acid, 2,6-naphthalenedicarboxylic acid and ethylene glycol, and mixtures of two or more of these polyesters are mainly used. Polyester as a constituent component is preferable.

The thickness of the film support used in the present invention is preferably 10 to 300 μm, particularly 20 to 150 μm. The film support of the present invention may be a laminate of two sheets. In this case, the type may be the same or different.

(Other functional layers)
In the filter which concerns on this invention, it is preferable to provide a functional layer for the purpose of the addition of the further function as needed. Moreover, there is an advantage that durability at the time of bending is improved by providing functionality. The functional layer is not particularly limited, but is a conductive layer, an antistatic layer, a gas barrier layer, an easy adhesion layer (adhesion layer), an antifouling layer, a deodorant layer, a droplet layer, an easy slip layer, Used for hard coat layer, abrasion-resistant layer, antireflection layer, electromagnetic wave shielding layer, ultraviolet absorption layer, infrared absorption layer, printing layer, fluorescent light emitting layer, hologram layer, release layer, adhesive layer, adhesive layer, laminated glass Examples include an intermediate film layer, a heat insulating layer, a heat ray reflective layer, and a heat dissipation layer.

As the ultraviolet absorber used in the ultraviolet absorbing layer, for example, the ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988, and JP-A-62-261476 can be used.

The thickness of the functional layer is preferably 0.1 μm to 50 μm, more preferably 1 to 20 μm.

<Hard coat layer>
The filter of the present invention preferably includes a hard coat layer as a surface protective layer for enhancing the scratch resistance. Specifically, it is preferable to laminate a hard coat layer containing a resin that is cured by heat, ultraviolet rays, or the like on the uppermost layer on the side opposite to the side having the dielectric multilayer film.

Examples of the curable resin used in the hard coat layer include a thermosetting resin and an ultraviolet curable resin. However, an ultraviolet curable resin is preferable because it is easy to mold, and among them, those having a pencil hardness of at least 2H. More preferred. Such cured resins can be used singly or in combination of two or more.

As such an ultraviolet curable resin, it is synthesized from, for example, a polyfunctional acrylate resin such as acrylic acid or methacrylic acid ester having a polyhydric alcohol, and acrylic acid or methacrylic acid having a diisocyanate and a polyhydric alcohol. Such polyfunctional urethane acrylate resins can be mentioned. Furthermore, polyether resins, polyester resins, epoxy resins, alkyd resins, spiroacetal resins, polybutadiene resins or polythiol polyene resins having an acrylate-based functional group can also be suitably used.

As reactive diluents for these resins, relatively low viscosity 1,6-hexanediol di (meth) acrylate, tripropylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, hexanediol (methacrylate) ) Bifunctional or higher functional monomers and oligomers such as acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, neopentylglycol di (meth) acrylate, and Acrylic esters such as N-vinylpyrrolidone, ethyl acrylate, propyl acrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, hexyl Methacrylic acid esters such as tacrylate, isooctyl methacrylate, 2-hydroxyethyl methacrylate, cyclohexyl methacrylate, nonylphenyl methacrylate, derivatives such as tetrahydrofurfuryl methacrylate and its caprolactone modified products, styrene, α-methylstyrene, acrylic acid, etc. A monofunctional monomer or the like can be used. These reactive diluents can be used alone or in combination of two or more.

Furthermore, as photosensitizers (radical polymerization initiators) for these resins, benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl methyl ketal and the like Alkyl ethers; acetophenones such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone; anthraquinones such as methylanthraquinone, 2-ethylanthraquinone, 2-amylanthraquinone; thioxanthone, 2,4 -Thioxanthones such as diethylthioxanthone and 2,4-diisopropylthioxanthone; Ketals such as acetophenone dimethyl ketal and benzyldimethyl ketal; Benzophenone and 4,4-bismethi Benzophenones such as amino benzophenone and azo compounds can be used. These may be used alone or in combination of two or more. In addition, tertiary amines such as triethanolamine and methyldiethanolamine; photoinitiators such as 2-dimethylaminoethylbenzoic acid and benzoic acid derivatives such as ethyl 4-dimethylaminobenzoate can be used in combination. it can. These radical polymerization initiators are used in an amount of 0.5 to 20 parts by weight, preferably 1 to 15 parts by weight, based on 100 parts by weight of the polymerizable component of the resin.

In addition, you may mix | blend a well-known general paint additive with the above-mentioned cured resin as needed. For example, a silicone-based or fluorine-based paint additive that imparts leveling or surface slip properties is effective in preventing scratches on the surface of a cured film, and in the case of using ultraviolet rays as active energy rays, When the additive bleeds to the air interface, the inhibition of curing of the resin by oxygen can be reduced, and an effective degree of curing can be obtained even under low irradiation intensity conditions.

The hard coat layer preferably contains inorganic fine particles. Preferable inorganic fine particles include fine particles of an inorganic compound containing a metal such as titanium, silica, zirconium, aluminum, magnesium, antimony, zinc or tin. The average particle size of the inorganic fine particles is preferably 1000 nm or less, and more preferably in the range of 10 to 500 nm, from the viewpoint of ensuring visible light transmittance. In addition, the inorganic fine particles have a higher bond strength with the cured resin forming the hard coat layer, and can be prevented from falling off the hard coat layer. Therefore, a photosensitive group having photopolymerization reactivity such as monofunctional or polyfunctional acrylate. Those in which is introduced into the surface are preferred.

The thickness of the hard coat layer is preferably 0.1 μm to 50 μm, more preferably 1 to 20 μm. If it is 0.1 μm or more, the hard coat property tends to be improved. Conversely, if it is 50 μm or less, the transparency tends to be improved.

The method for forming the hard coat layer is not particularly limited. For example, after preparing a coating liquid for hard coat layer containing the above components, the coating liquid is applied with a wire bar or the like, and the coating liquid is cured with heat and / or UV. And a method of forming a hard coat layer.

(Use)
The filter of the present invention can be used for various applications. For example, a colored film for decoration, a color filter that modulates the color of the light source, a reflective mirror for visible light or infrared light, a white LED, a fluorescent light, a color filter for organic EL lighting, etc. In particular, it is preferably used for agriculture where light from a light source is modulated to promote plant growth. As described above, narrow band light with a band edge such as red light of 640 nm to 690 nm and blue light of 420 nm to 470 nm are optimal for promoting photosynthesis and normal formation of leaves. In the case of conventional LED materials, the transmission wavelength region is determined depending on the material, so it cannot be designed to transmit the desired wavelength, but in the filter of the present invention, a filter is formed in accordance with the target set wavelength. Therefore, it can be used particularly for plant growth promotion. Therefore, a narrow band-pass filter that exhibits maximum transmittance in a blue light region of 400 nm to 500 nm or a red light region of 630 to 700 nm is suitable.

Also, plant growth is promoted by attaching the narrow band-pass filter of the present invention to a greenhouse or the like. That is, the present invention also includes a plant growth promoting method for promoting plant growth using the narrow band-pass filter. The target wavelength is appropriately set depending on the plant species and the plant part that is desired to promote growth.

(Filter manufacturing method)
There is no particular limitation on the method for producing the narrow band-pass filter of the present invention, and any method for producing a dielectric multilayer film can be used.

As a preferred form, (1) a method in which a high refractive index film and a low refractive index film are alternately coated on a substrate and dried to form a laminate, (2) after the laminate is formed by extrusion, The method of extending | stretching a laminated body and forming a film is mentioned.

Specific examples of the method (1) include the following forms: (1) A high refractive index film coating solution is applied on a substrate and dried to form a high refractive index film. A method of forming a low refractive index film by applying a refractive film coating liquid and drying; (2) A low refractive index film coating liquid is applied and dried on a substrate to form a low refractive index film. After that, a method of forming a film by applying a high refractive index film coating liquid and drying to form a film; (3) coating a high refractive index film coating liquid and a low refractive index film on the substrate A method of forming a film including a high refractive index film and a low refractive index film by alternately coating and drying the liquid alternately and successively; (4) A high refractive index film coating liquid and a low refractive index on a substrate And a method of forming a film containing a high refractive index film and a low refractive index film by simultaneously applying a multilayer coating with a film coating solution and drying. Especially, it is preferable that it is simultaneous multilayer coating of (4) from a viewpoint of production efficiency. In the refractive index film according to the present invention, a synthetic polymer such as polyvinyl alcohol, a water-soluble polymer such as gelatin and a thickening polysaccharide is used as a binder for preparing each layer coating liquid and laminating by simultaneous multilayering. It can be used suitably.

[Manufacturing method of multi-layer coating]
It is particularly suitable when a water-soluble polymer is contained as an organic polymer. A plurality of constituent layers including a high-refractive index film and a low-refractive index film can be appropriately selected from known coating methods, and simultaneously coated in water on a support, and then set and dried. . Examples of the coating method include a roll coating method, a rod bar coating method, an air knife coating method, a spray coating method, a curtain coating method, or US Pat. Nos. 2,761,419 and 2,761,791. A slide bead coating method using an hopper, an extrusion coating method, or the like is preferably used.

When the refractive index film contains a water-soluble polymer and metal oxide particles, a multilayer body is formed by multilayer coating, so that the mass ratio (F / B) of the water-soluble polymer and metal oxide particles in each film coating solution. Is preferably in the range of 0.3 to 10, more preferably 0.5 to 5.

Also, it is preferable that the time from simultaneous multilayer coating to sol-gel transition and setting is within 5 minutes, preferably within 2 minutes. Moreover, it is preferable to take time of 45 seconds or more.

Adjust the set time by adjusting the viscosity according to the concentration of metal oxide particles and other components, adjusting the binder mass ratio, and adding various known gelling agents such as gelatin, pectin, agar, carrageenan and gellan gum. It can be performed by adjustment.

Here, the term “set” refers to, for example, increasing the viscosity of the coating composition by lowering the temperature by applying cold air or the like to the coating, reducing the fluidity of the material between each layer and each layer, or gelling. Specifically, the time from application to set is what the finger has when the cold air of 5-10 ° C is applied to the coating film from the surface and the finger is pressed against the surface. Let's say lost time.

The temperature condition when using cold air is preferably 25 ° C. or lower, more preferably 10 ° C. or lower. The time for which the coating film is exposed to the cold air is preferably 10 seconds or more and 120 seconds or less, although it depends on the coating conveyance speed.

The solvent for preparing each coating solution for simultaneous multilayer coating is not particularly limited, but water, an organic solvent, or a mixed solvent thereof is preferable. In the present invention, an aqueous solvent can be used because polyvinyl alcohol is mainly used as the resin binder. Compared to the case where an organic solvent is used, the aqueous solvent does not require a large-scale production facility, so that it is preferable in terms of productivity and also in terms of environmental conservation.

Examples of the organic solvent include alcohols such as methanol, ethanol, 2-propanol and 1-butanol, esters such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate, diethyl ether, Examples thereof include ethers such as propylene glycol monomethyl ether and ethylene glycol monoethyl ether, amides such as dimethylformamide and N-methylpyrrolidone, and ketones such as acetone, methyl ethyl ketone, acetylacetone and cyclohexanone. These organic solvents may be used alone or in combination of two or more. From the viewpoint of environment and simplicity of operation, the solvent of the coating solution is preferably water or a mixed solvent of water and methanol, ethanol, or ethyl acetate, and more preferably water.

When the slide bead coating method is used, the viscosity of each coating solution at the time of simultaneous multilayer coating is preferably in the range of 5 to 100 mPa · s, more preferably 10 to 50 mPa · s in the temperature range of 25 to 60 ° C. It is the range of s. When the curtain coating method is used, the range of 5 to 1200 mPa · s is preferable, and the range of 25 to 500 mPa · s is more preferable.

The viscosity of the coating solution at 15 ° C. is preferably 100 mPa · s or more, more preferably 100 to 30,000 mPa · s, still more preferably 3,000 to 30,000 mPa · s, and most preferably 10 , 30,000 to 30,000 mPa · s.

As a coating and drying method, it is preferable that the coating solution is heated to 30 ° C. or higher and coated, and then the temperature of the formed coating film is once cooled to 1 to 15 ° C. and dried at 10 ° C. or higher. More preferably, the drying conditions are a wet bulb temperature of 5 to 50 ° C. and a film surface temperature of 10 to 50 ° C. Moreover, as a cooling method immediately after application | coating, it is preferable to carry out by a horizontal set system from a viewpoint of the formed coating-film uniformity.

For the extrusion step in (2) above, the method described in US Pat. No. 6,049,419 can be used. That is, a high-refractive-index film material polymer and other additives (high-refractive-index film-forming composition) and a low-refractive-film material polymer and other additives (low-refractive-index film-forming composition) are co-extruded. Can be used to form a high refractive index film and a low refractive index film.

As one embodiment, each refractive index film material is melted at 85 to 300 ° C. so as to have a viscosity suitable for extrusion, and various additives are added as necessary, so that both polymers are alternately formed into two layers. Can be extruded by an extruder. Next, the extruded laminated film is cooled and solidified by a cooling drum or the like to obtain a laminated body.

Thereafter, the laminate is heated and then stretched in two directions to obtain a narrow band filter.

As the stretching method, the unstretched film obtained by peeling from the above-mentioned cooling drum is subjected to a glass transition temperature (Tg) of −50 ° C. to Tg + 100 ° C. via a plurality of roll groups and / or a heating device such as an infrared heater. It is preferable that the film is heated inside and stretched in one or more stages in the film conveying direction (also referred to as the longitudinal direction). Next, it is also preferable to stretch the stretched film obtained as described above in a direction perpendicular to the film transport direction (also referred to as the width direction). In order to stretch the film in the width direction, it is preferable to use a tenter device.

When stretching in the film transport direction or the direction perpendicular to the film transport direction, it is preferable to stretch the film at a magnification of 1.1 to 4 times, more preferably 1.5 to 2 from the viewpoint of controlling the birefringence of the film. .5 times the range.

Also, heat processing can be performed subsequent to stretching. The thermal processing is preferably carried out in the range of Tg-100 ° C. to Tg + 50 ° C., usually for 0.5 to 300 seconds.

The heat processing means is not particularly limited and can be generally performed with hot air, infrared rays, a heating roll, microwaves, or the like, but is preferably performed with hot air in terms of simplicity. The heating of the film is preferably increased stepwise.

The heat-processed film is usually cooled to Tg or less, and the clip gripping portions at both ends of the film are cut and wound. In addition, it is preferable that the cooling is gradually performed from the final heat processing temperature to Tg at a cooling rate of 100 ° C. or less per second.

The means for cooling is not particularly limited, and can be performed by a conventionally known means. In particular, it is preferable to perform these treatments while sequentially cooling in a plurality of temperature ranges from the viewpoint of improving the dimensional stability of the film. The cooling rate is a value obtained by (T1−Tg) / t, where T1 is the final heat processing temperature and t is the time until the film reaches Tg from the final heat processing temperature.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

Example 1
(Sample 1: Comparative Example 1)
On a 50 μm-thick polyethylene terephthalate (PET) film (A4300: double-sided easy-adhesion layer, manufactured by Toyobo Co., Ltd., hereinafter abbreviated as PET film), silver / MgF ₂ is PET / silver (40 nm) / An MDM type narrow-band bandpass filter (Δλ / λ0 × 100 = 11%, maximum transmittance wavelength λ = 550 nm) was formed by stacking (MgF ₂ (143.5 nm)) ² / silver (40 nm). Since the refractive index of MgF ₂ is 1.35, the optical film thickness of each refractive index layer in the narrow-band bandpass filter of Comparative Example 1 is (λ / 4-96). %) To (λ / 4 + 44%), where λ / 4-96% means λ / 4-λ / 4 × 96/100, and so on.

In the following examples and comparative examples, the numerical value in parentheses described next to the material of the layer structure is the physical film thickness value of each refractive index film.

(Sample 2: Comparative Example 2)
On a PET film, silver, TiO ₂ , SiO ₂ , and MgF ₂ are converted into PET / TiO ₂ (76 nm) / (SiO ₂ (100 nm) / TiO ₂ (64 nm)) ³ / MgF ₂ using a known sputtering method. (164 nm) / silver (70 nm) / MgF ₂ (192 nm) / (TiO ₂ (56 nm) / SiO ₂ (86 nm)) ³ / TiO ₂ (78 nm) / SiO ₂ (130 nm) stacked in this order, narrow A band-pass filter (Δλ / λ0 × 100 = 4%, maximum transmittance wavelength λ = 550 nm) was produced. Since the refractive index of TiO ₂ is 2.6 and the refractive index of SiO ₂ is 1.5, the optical film thickness of each refractive index layer in the narrowband bandpass filter of Comparative Example 2 is (λ / 4). -93%) to (λ / 4 + 93%).

(Sample 3: Comparative Example 3)
On a PET film, using a known sputtering method, Ta ₂ O ₅ and SiO ₂ are changed into PET / (Ta ₂ O ₅ (70 nm) / SiO ₂ (106 nm)) ⁵ / Ta ₂ O ₅ (70 nm) / SiO 2. ₂ (212 nm) / Ta ₂ O ₅ (70 nm) / (SiO ₂ (106 nm) / Ta ₂ O ₅ (70 nm)) ⁵ / SiO ₂ (212 nm) laminated in this order, a dielectric multilayer film made of an inorganic material A narrow band-pass filter (Δλ / λ0 × 100 = 1.3%, maximum transmittance wavelength λ = 643 nm) was produced. Since the refractive index of Ta ₂ O ₅ is 2.3, the optical film thickness of each refractive index layer in the narrow-band bandpass filter of Comparative Example 3 is in the range of (λ / 4−1%) to λ / 4. Met.

(Sample 4: Example 1)
According to the melt extrusion method described in US Pat. No. 6,049,419, polyethylene naphthalate (PEN) and polymethylmethacrylate (PMMA) are (PMMA (116 nm) / PEN (102 nm)) ⁵⁰ / (PMMA (100 nm) / PEN (88 nm). ^{)) 25 /PMMA(183nm=91.5nm×2)/(PEN(80nm)/PMMA(91nm) 25 / PEN} (80nm) / (PMMA (83m) / PEN (73nm) was laminated to the ⁵⁰ order, vertical Double-width, double-width, pasted with 25 μm PET film, dielectric multilayer narrow band-pass filter containing organic material (Fig. 2, Δλ / λ0 × 100 = 1.6%, maximum transmittance) Wavelength λ = 574 nm) The configuration of the narrow band-pass filter of Example 1 is (L ₁ H ₁ ) ⁵⁰ [(L ₂ H ₂ ) ²⁵ / 2L ₃ / (H ₃ L ₄ ) ²⁵ / H ₄ ] (L ₅ H ₅ ) ⁵⁰ ([] inner layer structure 2, m = n = 25, s = 2) where L _X represents a low refractive index film, H _Y represents a high refractive index film (X and Y are integers), and the same applies to the following examples, where the refractive index of PMMA is 1.7. Since the refractive index of PEN is 1.5, the optical film thickness of each refractive index layer in the narrow-band bandpass filter of Example 1 is (λ / 4-24%) to (λ / 4 + 37%). It was in range.

(Sample 5: Example 2)
Similar to Sample 4, (PMMA (117 nm) / PEN (103 nm)) ²⁵ / (PMMA (108 nm) / PEN (96 nm)) ²⁵ / (PMMA (100 nm) / PEN (88 nm)) ²⁵ / (PMMA (92 nm) ^{/ PEN (81nm)) 25 /} (PMMA (83nm) / PEN (74nm)) 24 / PMMA (83nm) / PEN (150nm) / (PMMA (75nm) / PEN (66nm)) laminated in this order ^25, 25 [mu] m of A dielectric type narrow-band bandpass filter (FIG. 3, Δλ / λ0 × 100 = 4.2%, maximum transmittance wavelength λ = 475 nm) was prepared by laminating with a PET film. The configuration of the narrow band-pass filter of Example 2 is (L ₁ H ₁ ) ²⁵ / (L ₂ H ₂ ) ²⁵ / (L ₃ H ₃ ) ²⁵ / (L ₄ H ₄ ) ²⁵ [(L ₅ H ₅ ) ²⁴ / L ₆ / 2H ₆ / L ₇ / (H ₇ L ₇ ) ²⁴ / H ₇ ] ([] inner layer configuration 2, m = n = 24, s = 2). The optical film thickness of each refractive index layer in the narrow-band bandpass filter of Example 2 was in the range of (λ / 4-67%) to (λ / 4 + 43%).

(Sample 6: Example 3)
Similar to Sample 4, (PMMA (117 nm) / PEN (103 nm)) ²⁵ / PMMA (217 nm) / PEN (96 nm) / (PMMA (108 nm) / PEN (96 nm)) ²⁴ / (PMMA (100 nm) / PEN ( ^{88nm)) 25 / PMMA (183nm} ) / PEN (81nm) / (PMMA (92nm) / PEN (81nm)) 24 / (PMMA (83nm) / PEN (74nm)) 25 / (PMMA (75nm) / PEN (66nm )) Laminated in the order of ²⁵ , laminated with 25 μm PET film, dielectric multilayer narrow band-pass filter containing organic material (FIG. 4, (1) Δλ / λ0 × 100 = 1.8%, one Eye maximum transmittance wavelength λ = 574 nm, (2) Δλ / λ0 × 100 = 2.3% Second maximum transmittance wavelength λ 673nm) was prepared. The configuration of the narrow band pass filter of Example 3 is [(L ₁ H ₁ ) ²⁵ / 2L ₂ / (H ₂ L ₃ ) ²⁴ / H ₃ ] [(L ₄ H ₄ ) ²⁵ / 2L ₅ / (H ₆ L ₆ ) ²⁴ / H ₆ ] (L ₇ H ₇ ) ²⁵ / (L ₈ H ₈ ) ²⁵ ([] inner layer configuration 2, m = 25, n = 24, s = 2). The optical film thickness of each refractive index layer in the narrow-band bandpass filter of Example 3 is in the range of (λ / 4-31%) to (λ / 4 + 39%) with respect to λ = 574 nm, and λ = For 673 nm, it was in the range of (λ / 4-41%) to (λ / 4 + 18%).

(Sample 7: Example 4)
Sample 6 PMMA is polyethylene terephthalate (inherent viscosity 0.65, melting point 255 ° C., F20S manufactured by Toray Industries, Inc.), PEN is polyethylene terephthalate copolymer (inherent viscosity 0.72, cyclohexanedicarboxylic acid component 29 mol%, spiroglycol component 20 mol%) Dielectric multilayer film in the same manner as in Sample 6, except that the copolymer was changed to PBT (Toraycon 1401-X06, manufactured by Toray Industries, Inc.) (polyethylene terephthalate copolymer: PBT = 1: 0.2 (mass ratio)). Is a dielectric type narrow-band bandpass filter containing an organic polymer ((1) Δλ / λ0 × 100 = 1.8%, first maximum transmittance wavelength λ = 574 nm, (2) Δλ / λ0 × 100 = 2 3% and the second maximum transmittance wavelength λ = 673 nm). Since the refractive index of polyethylene terephthalate is 1.7 and the refractive index of polyethylene terephthalate copolymer + PBT is 1.5, the optical film thickness of each refractive index layer in the narrow-band bandpass filter of Example 4 is λ = For 574 nm, the range is from (λ / 4-31%) to (λ / 4 + 39%), and for λ = 673 nm, the range is from (λ / 4-41%) to (λ / 4 + 18%). It was in range.

(Sample 8: Example 5)
Dielectric type narrowband bandpass with dielectric multilayer film containing organic polymer in the same way as sample 6, except that PMMA of sample 6 is changed to vinylidene fluoride (DYNEON THVP 2030GX, DYNEON, LLC) which is F-based polymer Filter ((1) Δλ / λ0 × 100 = 1.8%, first maximum transmittance wavelength λ = 574 nm, (2) Δλ / λ0 × 100 = 2.3%, second maximum transmittance wavelength (λ = 673 nm). Since the refractive index of vinylidene fluoride is 1.7, the optical film thickness of each refractive index layer in the narrow-band bandpass filter of Example 5 is (λ / 4−31%) for λ = 574 nm. ) To (λ / 4 + 39%), and for λ = 673 nm, the range was (λ / 4-41%) to (λ / 4 + 18%).

(Sample 9: Example 6)
(Preparation of coating solution for low refractive index film)
To 500 parts by mass of pure water, 10.0 parts by mass of water-soluble resin PVA224 (manufactured by Kuraray Co., Ltd., saponification degree 88%, polymerization degree 1000) is added, and further water-soluble resin R1130 (manufactured by Kuraray Co., Ltd., By adding 5.0 parts by mass of silanol-modified polyvinyl alcohol) and then 2.0 parts by mass of water-soluble resin Nichigo G polymer AZF8035W (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) An aqueous solution of a water-soluble resin was obtained.

Next, the entire amount of the water-soluble resin aqueous solution was added to and mixed with 350 parts by mass of 10% by mass acidic silica sol (Snowtex (registered trademark) OXS, manufactured by Nissan Chemical Industries, Ltd.) containing silica fine particles having an average particle diameter of 5 nm. Furthermore, 0.3 parts by mass of Lapisol A30 (manufactured by Nippon Oil & Fats Co., Ltd.) was added as an anionic activator, and after stirring for 1 hour, the coating solution for low refractive index film was prepared by finishing to 1000.0 g with pure water .

<Preparation of aqueous dispersion of titanium oxide sol>
Sodium hydroxide aqueous solution (concentration 10 mol / L) was added to 10 L of an aqueous suspension (TiO ₂ concentration 100 g / L) in which titanium oxide hydrate was suspended in water with stirring, and the temperature was raised to 90 ° C. After warming and aging for 5 hours, it was neutralized with hydrochloric acid, filtered and washed with water. In the above reaction (treatment), titanium oxide hydrate was obtained by thermal hydrolysis of an aqueous titanium sulfate solution according to a known method.

The titanium oxide hydrate treated with the base was suspended in pure water so that the TiO ₂ concentration was 20 g / L, and 0.4 mol% of citric acid was added to the amount of TiO ₂ with stirring to raise the temperature. When the liquid temperature reached 95 ° C., concentrated hydrochloric acid was added to a hydrochloric acid concentration of 30 g / L, and the mixture was stirred for 3 hours while maintaining the liquid temperature.

When the pH and zeta potential of the obtained titanium oxide sol solution were measured, the pH was 1.4 and the zeta potential was +40 mV. Furthermore, when the particle size was measured with a Zetasizer Nano manufactured by Malvern, the average particle size was 35 nm, and the monodispersity was 16%. Also, the titanium oxide sol solution was dried at 105 ° C. for 3 hours to obtain a particle powder, and X-ray diffraction measurement was performed using JDX-3530 type manufactured by JEOL Datum Co., Ltd. to confirm that the particles were rutile type particles. did. Moreover, the volume average particle diameter was 10 nm.

1 kg of pure water was added to 1 kg of a 20.0 mass% titanium dioxide sol aqueous dispersion containing rutile-type titanium oxide fine particles having a volume average particle diameter of 10 nm to obtain a 10.0 mass% titanium oxide sol aqueous dispersion.

<Preparation of silicic acid aqueous solution>
An aqueous silicic acid solution having a SiO ₂ concentration of 2.0 mass% was prepared.

<Preparation of silica-modified titanium oxide sol aqueous dispersion>
2 kg of pure water was added to 0.5 kg of the 10.0 mass% titanium oxide sol aqueous dispersion, and the mixture was heated to 90 ° C. Next, 1.3 kg of the above silicic acid aqueous solution was gradually added, and heat treatment was performed at 175 ° C. for 18 hours in an autoclave. Thereafter, further concentration was performed to obtain a silica-modified titanium dioxide sol aqueous dispersion containing a silica-modified titanium dioxide sol having a rutile structure and a coating layer of SiO ₂ at a concentration of 20.0% by mass.

(Preparation of coating solution for high refractive index film)
20.0% by mass of silica-modified titanium oxide particle sol aqueous dispersion obtained above, 289 parts by mass, 1.92% by mass of citric acid aqueous solution 105 parts by mass, 10% by mass of allyl ether copolymer (AKM-0531, JP (Oil Corporation) 20 parts by mass of an aqueous solution and 90 parts by mass of a 3% by mass boric acid aqueous solution were mixed to prepare a silica-modified titanium oxide sol dispersion.

Next, while stirring the silica-modified titanium oxide sol dispersion, 20 parts by mass of pure water and 335 parts by mass of a 5.0% by mass aqueous solution of polyvinyl alcohol (PVA217, manufactured by Kuraray Co., Ltd.) were added. Furthermore, 20 parts by mass of a 1% by mass aqueous solution of an anionic surfactant (Lapisol A30, manufactured by NOF Corporation) was added, and finally the total amount was 1000 parts by mass with pure water to prepare a coating solution for a high refractive index film. did.

(Formation of optical film)
As the coating apparatus, a slide hopper coating apparatus capable of simultaneously coating 21 layers was used. On the 30 cm × 30 cm size 50 μm thick polyethylene terephthalate (PET) film (A4300: double-sided easy-adhesive layer, manufactured by Toyobo Co., Ltd.), the coating solution for the low refractive index film and the coating solution for the high refractive index film prepared above are used. PET / (High refractive index film (78 nm) / Low refractive index film (119 nm)) ⁵ / High refractive index film (119 nm) / Low refractive index film (238 nm) / (High refractive index film) (78 nm) / low refractive index film (119 nm)) ⁵ / high refractive index film 78 nm) / low refractive index film (238 nm) The layers were applied simultaneously. Immediately after that, after setting the film surface by blowing cold air for 1 minute under the condition that the film surface is 15 ° C. or less, the dielectric multilayer film is a dielectric film containing an organic polymer and a metal oxide by drying by blowing hot air of 80 ° C. A body-shaped narrow band-pass filter (FIG. 5, Δλ / λ0 × 100 = 3.8%, set wavelength λ = 666 nm) was produced. The configuration of the narrow-band bandpass filter of Example 6 is [(H ₁ L ₁ ) ⁵ / H ₁ / 2L ₁ / H ₁ / (L ₁ H ₁ ) ⁵ / L ₁ ] L ₁ (inside [], Corresponding to the layer structure 3 above, m = n = 5, s = 2). Since the refractive index of the high refractive index film is 1.9 and the refractive index of the low refractive index film is 1.4, the optical film thickness of each refractive index layer in the narrowband bandpass filter of Example 6 is (λ / 4-11%) to (λ / 4 + 36%).

(Sample 10: Example 7)
Similar to Sample 9, the layer structure is PET / (low refractive index film (119 nm) / high refractive index film (78 nm) ⁵ / low refractive index film (119 nm) / high refractive index film (157 nm) / low refractive index film ( 119 nm) / (High refractive index film (78 nm) / Low refractive index film (119 nm)) ⁵ / Similarly, the dielectric multilayer film contains an organic polymer and a metal oxide, except that it is a high refractive index film (157 nm). Then, a dielectric type narrow band-pass filter (FIG. 6, Δλ / λ0 × 100 = 5.1%, set wavelength λ = 625 nm transmission) having a cavity of a high refractive index film was produced. The configuration of the band-pass filter is L ₁ [(H ₁ L ₁ ) ⁵ / 2H ₂ / (L ₁ H ₁ ) ⁵ L ₁ )] 2H ₂ (inside [], the layer configuration 1 corresponds to m = n = 5, s = 2). The optical film thickness of each refractive index layer in the narrow band-pass filter of Example 7 was in the range of (λ / 4-5%) to (λ / 4 + 7%).

(Sample 11: Example 8)
On the PET film opposite to the surface on which the dielectric multilayer film of Sample 10 is formed, a mixture layer having a volume ratio of ATO (antimony-doped tin oxide) / PVA224 = 4/6 is applied in a dry film thickness of 8 μm. Sample 11 was prepared in the same manner as Sample 10 except that a visible light shielding layer was provided.

(Sample 12: Example 9)
On the PET film opposite to the surface on which the dielectric multilayer film of Sample 10 is formed, PVA224, TINUVIN-P (manufactured by Ciba Japan Co., Ltd.), which is an ultraviolet absorber, and TINUVIN326 (manufactured by Ciba Japan Co., Ltd.) Was provided with a functional film (ultraviolet absorption layer) having a dry film thickness of 3 μm containing 80/15/5 in volume ratio.

(Sample 13: Example 10)
7.5 parts by mass of UV curable hard coat material (UV-7600B, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) is added to 90 parts by mass of methyl ethyl ketone solvent, and then a photopolymerization initiator (Irgacure (registered trademark) 184, Ciba Specialty) (Chemicals Co., Ltd.) 0.5 parts by mass was added and stirred and mixed. Next, 2 parts by mass of ATO powder (ultrafine particle ATO, manufactured by Sumitomo Metal Mining Co., Ltd.) was added and stirred at high speed with a homogenizer to prepare a coating solution for a hard coat layer.

On the surface of the PET film of Sample 10 opposite to the side where the dielectric multilayer film is provided, the hard coat layer coating solution is applied with a wire bar to a dry film thickness of 3 μm, and hot air is applied at 70 ° C. for 3 minutes. Dried. After that, by curing with an irradiation amount of 400 mJ / cm ² with a UV curing device (using a high-pressure mercury lamp) manufactured by Eye Graphics Co., Ltd. in the atmosphere, an infrared light blocking hard coat layer is formed. Sample 13 was produced.

(Sample 14: Comparative Example 4)
On a PET film, using a known sputtering method, Ta ₂ O ₅ and SiO ₂ are changed into PET / (SiO ₂ (110 nm) / Ta ₂ O ₅ (64.5 nm) ⁵ / SiO ₂ (110 nm) / Ta ₂ ). O _{5 (129nm)} / stacked in this order _{SiO 2 (110nm) / (Ta} 2 O 5 (64.5nm) / SiO 2 (110nm)) 5 / Ta 2 O 5 (129nm), a dielectric multilayer film made of an inorganic substance A narrow-band bandpass filter (Δλ / λ0 × 100 = 5.1%, maximum transmittance wavelength λ = 625 nm) was produced, and the configuration of the narrow-band bandpass filter of Comparative Example 4 was L ₁ [(H ₁ L ₁ ) ⁵ / 2H ₂ / (L ₁ H ₁ ) ⁵ L ₁ )] 2H ₂ (inside [], the layer configuration 1 corresponds to m = n = 5, s = 2). The optical film thickness of each refractive index layer in the narrow-band bandpass filter of Comparative Example 4 was in the range of (λ / 4-5%) to (λ / 4 + 6%).

(Sample 15: Example 11)
Layer structure is PET / (low refractive index film (119 nm) / high refractive index film (78 nm) ⁵ / low refractive index film (119 nm) / high refractive index film (180 nm) / low refractive index film (119 nm) / (high refractive index The dielectric multilayer film contains an organic polymer and a metal oxide in the same manner as in Example 10 except that the refractive index film (78 nm) / low refractive index film (119 nm)) ⁵ / high refractive index film (180 nm) is used. A dielectric type narrow band-pass filter (FIG. 7, Δλ / λ0 = 3.0%, set wavelength λ = 649 nm transmission) having a cavity of a refractive index film was produced. The optical film thickness of each refractive index layer was in the range of (λ / 4-9%) to (λ / 4 + 5%).

(Measurement of transmittance)
A spectrophotometer (U-4000 model, manufactured by Hitachi, Ltd.) is attached with a transmission unit, and after baseline correction by blank measurement, the surface side of the dielectric multilayer film is used as the measurement surface, and 0.5 nm in the region of 400 to 700 nm. The transmittance at 600 points was measured at intervals, and the wavelength and transmittance of the narrowband passband were obtained.

(Durability evaluation)
<Bending test>
For each of the above prepared samples, based on a bending test method based on JIS K5600-5-1 (1999), using a bending tester type 1 (manufactured by Imoto Seisakusho, model IMC-AOF2, mandrel diameter φ20 mm), 300 Bending tests were performed. The transmittance ratio (the transmittance (%) after the bending test with respect to the transmittance (%) before the bending test) at the wavelength of the narrow band pass band before and after the bending test was determined. It represents that the flexibility at the time of bending is excellent, so that the value of the transmittance ratio is small.

<Bending test after forced deterioration> For each of the above-prepared samples, it was put into a thermo-device set at a temperature of 60 ° C. and a relative humidity of 85%, and the transmittance ratio at the wavelength of the narrow band pass band before and after the forced deterioration (forced deterioration) The transmittance (%) after the moisture and heat resistance test with respect to the transmittance (%) before the test was determined. The smaller the transmittance ratio value, the better the flexibility at high temperature and high humidity.

Table 2 shows the durability evaluation results. It can be seen that the configuration satisfying the present invention is excellent in durability in both the bending test and the forced deterioration test with little decrease in wavelength transmittance in a narrow band pass band.

This application is based on Japanese Patent Application No. 2012-005083 filed on January 13, 2012, the disclosure content of which is referenced and incorporated as a whole.

Claims (8)

1. Dielectric type narrow-band bandpass filter with dielectric multilayer film containing organic polymer.
2. The narrow band-pass filter according to claim 1, wherein the dielectric multilayer film includes metal oxide particles.
3. The narrow-band bandpass filter according to claim 1 or 2, wherein the dielectric multilayer film includes a layer structure represented by the following (1):
   

   

   At this time, H ₁ , H ₂ , and H ₃ are dielectric multilayer films having an optical film thickness of (λ / 4−λ / 4 × 0.5) or more and (λ / 4 + λ / 4 × 0.5) or less. A dielectric multilayer film having a high refractive index film, wherein L ₁ and L ₂ have an optical film thickness of (λ / 4−λ / 4 × 0.5) or more and (λ / 4 + λ / 4 × 0.5) or less Λ represents the maximum transmittance wavelength in the narrow band pass band of the spectral transmittance curve of the filter, m and n are integers of 1 or more, and s is an integer of 2 or more. (H ₁ L ₁ ) ^m and (L ₂ H ₃ ) ⁿ mean that (H ₁ L ₁ ) is repeated m times and (L ₂ H ₃ ) is repeated n times, respectively. , SH is a cavity layer.
4. The dielectric narrow band-pass filter according to any one of claims 1 to 3, further comprising a light shielding means or a functional layer different from the dielectric multilayer film.
5. The narrow band-pass filter according to claim 4, wherein the functional layer is a hard coat layer.
6. The narrowband according to any one of claims 1 to 5, wherein a wavelength indicating the maximum transmittance exists in a region of 400 nm to 500 nm or a wavelength indicating the maximum transmittance exists in a region of 630 nm to 700 nm. Bandpass filter.
7. The narrow-band bandpass filter according to any one of claims 1 to 6, which is used for promoting plant growth.
8. A plant growth promoting method for promoting plant growth using the narrow-band bandpass filter according to any one of claims 1 to 6.

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