JP2014071419A - Optical film, and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical film which can be produced with high productivity and offers superior durability, and to provide a manufacturing method therefor.SOLUTION: An optical film which includes: an optical interference film comprising a high refractive index layer containing at least titanium oxide particles and a low refractive index layer containing at least silicon oxide particles laminated on a transparent substrate, and selectively reflects light in a predefined wavelength range. The high refractive index layer is formed by alternately spray-coating a coating liquid containing a first water-soluble polymer and cationic titanium oxide particles and another coating liquid containing a second water-soluble polymer and anionic titanium oxide particles, while the low refractive index layer is formed by alternately spray-coating a coating liquid containing a third water-soluble polymer and cationic silicon oxide particles and another coating liquid containing a fourth water-soluble polymer and anionic silicon oxide particles.

Description

  The present invention relates to an optical film that selectively reflects light in a specific wavelength region that is excellent in productivity and bending resistance, and a method for producing the same, and particularly suitable for an ultraviolet light reflection film, a heat shield film, a visible light reflection film, and the like. It is related with the optical film which can be used, and its manufacturing method.

  Conventionally, in an optical film produced by alternately laminating a high refractive index layer and a low refractive index layer on a substrate, light in a specific wavelength region is reflected by adjusting the optical film thickness of the refractive index layer. It is known that it can be designed as follows.

  As such a thin film forming technique, there is provided a method of forming a film by applying an anionic organic layer and a cationic organic layer by a dip method, drying and laminating (see, for example, Patent Document 1). In the dip method, the processing steps are complicated and the productivity is low.

  In addition, a method of forming a thin film by alternately laminating an anionic organic layer and a cationic inorganic layer by spray coating to form a thin film is also provided (for example, see Patent Document 2). Only ultra-thin films in the range of 10 nm can be produced.

  Therefore, as a method capable of forming a thin film having a desired film thickness, organic substances and titanium oxide particles are alternately laminated on a glass substrate by spray coating and then baked to remove the organic substances, and further, organic substances and silica particles. There is provided a method for forming a thin film by repeating a series of treatments in which organic substances are removed by firing after alternately laminating layers by spray coating (see, for example, Non-Patent Document 1).

JP 2003-203099 A US Pat. No. 8,234,998

Langmuir 2011, 27, 7860-7867

  However, in the prior art described in Non-Patent Document 1, the bending resistance of the thin film formed on the substrate is low. In addition, since it is necessary to perform a baking treatment to remove organic substances, it cannot be applied when the substrate is a resin film or the like, and the productivity is high because it is a method of repeating the coating treatment and the baking treatment. Low.

  Then, an object of this invention is to provide the optical film excellent in bending tolerance and productivity, and its manufacturing method.

In order to achieve the above object of the present invention, according to one aspect of the present invention,
An optical interference film formed by laminating a high refractive index layer containing at least titanium oxide particles and a low refractive index layer containing at least silicon oxide particles on a transparent substrate, and In an optical film that selectively reflects,
The high refractive index layer includes a coating liquid containing a first water-soluble polymer and cationic titanium oxide particles, and a coating liquid containing a second water-soluble polymer and anionic titanium oxide particles. Formed by spraying,
The low refractive index layer includes a coating solution containing a third water-soluble polymer and cationic silicon oxide particles, and a coating solution containing a fourth water-soluble polymer and anionic silicon oxide particles. An optical film is provided that is formed by spray coating.

In the optical film, preferably
The anionic titanium oxide particles are titanium oxide particles coated with a silicon-containing hydrated oxide.

In the optical film, preferably
At least the first water-soluble polymer and the second water-soluble polymer are different, or the third water-soluble polymer and the fourth water-soluble polymer are different.

In the optical film, preferably
At least the first water-soluble polymer and the second water-soluble polymer are the same type of water-soluble polymer and have different characteristics, or the third water-soluble polymer and the fourth water-soluble polymer are different from each other. The water-soluble polymer is the same type of water-soluble polymer and has different characteristics.

In the optical film, preferably
At least the first water-soluble polymer and the second water-soluble polymer are polyvinyl alcohols having different saponification degrees and / or polymerization degrees, or the third water-soluble polymer and the second water-soluble polymer are the same. The four water-soluble polymers are polyvinyl alcohols having different saponification degrees and / or polymerization degrees.

In the optical film, preferably
Used as an ultraviolet light reflecting film that reflects ultraviolet light.

In the optical film, preferably
Used as an infrared light reflecting film that reflects infrared light.

In the optical film, preferably
Used as a visible light reflecting film that reflects visible light.

In the optical film, preferably
Used as an antireflection film.

According to another aspect of the invention,
An optical interference film formed by laminating a high refractive index layer containing at least titanium oxide particles and a low refractive index layer containing at least silicon oxide particles on a transparent substrate, and In the method for producing a selectively reflecting optical film,
The coating solution containing the first water-soluble polymer and the cationic titanium oxide particles and the coating solution containing the second water-soluble polymer and the anionic titanium oxide particles are alternately spray-coated, and the high Forming a refractive index layer;
The coating solution containing the third water-soluble polymer and the cationic silicon oxide particles and the coating solution containing the fourth water-soluble polymer and the anionic silicon oxide particles are alternately spray-coated, and the low And a step of forming a refractive index layer. A method for producing an optical film is provided.

  According to the present invention, it is possible to provide an optical film having high bending resistance and high productivity, and a manufacturing method thereof.

It is a schematic block diagram which shows the manufacturing apparatus which manufactures the optical film which concerns on this invention.

Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail, but the present invention is not limited to these.
In the present invention, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

  The optical film according to the present invention has an optical interference film formed by laminating a high refractive index layer and a low refractive index layer on a transparent substrate. The high refractive index layer is formed by alternately spraying cationic fine particles containing titanium oxide and anionic fine particles containing titanium oxide, and the low refractive index layer is made of cationic fine particles containing silicon oxide. The anionic fine particles containing silicon oxide are alternately spray-coated.

<Membrane design>
In the optical film according to the present invention, the difference in refractive index between the adjacent high refractive index layer and low refractive index layer is preferably 0.2 or more, more preferably 0.3 or more. Moreover, although there is no restriction | limiting in particular in an upper limit, Usually, it is 1.4 or less. Here, the refractive index difference between the high refractive index layer and the low refractive index layer is actually the difference between the maximum refractive index point in the high refractive index region and the minimum refractive index point in the low refractive index region.

  Reflection at the interface between adjacent layers depends on the refractive index ratio between the layers, so that the larger the refractive index ratio, the higher the reflectance can be achieved with a smaller number of layers. In addition, when the optical path difference between the reflected light on the surface of the layer and the reflected light on the bottom of the layer is a relationship expressed by n · d = wavelength / 4 when viewed as a single layer film, the reflected light is controlled to be strengthened by the phase difference. The reflectance can be increased. Here, n is the refractive index, d is the physical film thickness of the layer, and n · d is the optical film thickness. By utilizing this optical path difference, reflection can be controlled. When the reflection center wavelength is set, this relationship is used to control the refractive index and film thickness of each layer to control the reflection of visible light and near infrared light. That is, the reflectance in a specific wavelength region can be improved by the refractive index of each layer, the film thickness of each layer, and the way of stacking each layer.

In the optical film which concerns on this invention, it can design so that a visible light average reflectance may provide the area | region of 30% or more and 100% or less, for example. In such an optical reflection film, the preferable refractive index of the high refractive index layer is 1.70 to 2.50, more preferably 1.80 to 2.20. Moreover, as a preferable refractive index of a low refractive index layer, it is 1.10-1.60, More preferably, it is 1.30-1.55. The preferred film thickness for visible light reflection is 30 nm to 130 nm for one layer, more preferably 50 nm to 85 nm, according to the formula n · d = wavelength / 4.
The average visible light reflectance is a range of 400 to 700 nm with a spectrophotometer (U-4000 type manufactured by Hitachi, Ltd.) attached with a 5 ° reflection unit, with the surface side of the optical reflection layer as the measurement surface, The reflectivity at 151 points is measured at intervals of 2 nm, and the value obtained by adding all the obtained reflectivities can be measured by dividing by 151.

  In the alternately laminated unit comprising the high refractive index layer and the low refractive index layer in the present invention, a thick film layer having a film thickness of 600 nm to 1200 nm can be preferably used for any one layer. By using a thick film layer, (1) the reflected wavelength range can be broadened, (2) when used in a layer adjacent to the support, the adhesion to the support can be improved, (3) the thick film is The effect of exhibiting the function of stress relaxation and improving the physical properties of the film with a laminated film can be obtained. More preferably, it is 700 nm to 1000 nm.

  In the present invention, a plurality of alternately laminated units can be used. By changing the optical film thickness for each unit, (1) the reflected wavelength range can be broadened, (2) the band edge can be sharpened, (3) ripple can be reduced, (4) higher order Reflection can be suppressed, (5) the band shift can be reduced by changing the incident angle, and (6) the optical reflection characteristics can be suppressed from being changed due to different polarizations. Especially in (1), by laminating the visible light reflection unit and the near infrared light reflection unit, it is possible to form a heat-shielding film in the reflection mode without using a light absorber, and to manufacture and absorb heat. There is no merit in preventing thermal cracking.

  In the present invention, it is composed of alternating high-refractive index layers and low-refractive index alternating layer units, where n is the total number of the high-refractive index layers and the low-refractive index layers, that is, the total number of layers. The total film thickness of the constituent layer (also referred to as the lower layer region) on the transparent base material side is Σd1, and the constituent layer from the reference position to the outermost layer (also referred to as the upper layer region) with reference to the position of 1/2 the number of layers. ) Is the total film thickness Σd2, the film thickness ratio Σd1 / Σd2 is preferably 1.05 or more and 1.80 or less.

  When the total number n of layers is an even number, the boundary region (n / 2) between the lower layer region from layer 1 to layer n / 2 and the upper layer region from layer n / 2 + 1 to layer n is It becomes an interface between the layer n / 2 and the layer n / 2 + 1. Further, when the total number n of layers is an odd number, the boundary area on the lower layer side of the layer corresponding to the boundary area (n + 1/2) with reference to the layer corresponding to the boundary area (n + 1/2). The total film thickness of the constituent layers up to the transparent substrate excluding the layer corresponding to (n + 1/2) is Σd1, and on the upper layer side of the layer corresponding to the boundary region (n + 1/2), the boundary region (n + 1 / The total film thickness of the constituent layers up to the outermost layer excluding the layer corresponding to 2) is defined as Σd2.

<Optical interference film>
The optical film according to the present invention is provided with an optical interference film formed by laminating a high refractive index layer and a low refractive index layer on a transparent substrate. These high refractive index layer and low refractive index layer will be described below. The average particle diameter of the metal oxide fine particles contained in the high refractive index layer and the low refractive index layer was determined by observing the particles themselves or the particles appearing on the cross section or surface of the layer with an electron microscope and 1,000 arbitrary The particle diameter of each particle is measured and obtained as a simple average value (number average). Here, the particle diameter of each particle is represented by a diameter assuming a circle equal to the projected area.

《High refractive index layer》
The high refractive index layer in the present invention comprises a coating liquid containing a first water-soluble polymer and cationic titanium oxide particles, a coating liquid containing a second water-soluble polymer and anionic titanium oxide particles, Are formed by alternately applying by spray coating, the layer containing the first water-soluble polymer and the cationic titanium oxide particles, and the second water-soluble polymer and the anionic titanium oxide particles are contained. Layers are alternately stacked.

In addition to the cationic titanium oxide particles, anionic titanium oxide particles, the first water-soluble polymer, and the second water-soluble polymer, the high refractive index layer may contain a curing agent, amino acid, and various additives as necessary. An agent or the like is selected and contained.
Further, the thickness per layer of the high refractive index layer is preferably 20 to 800 nm, and can be appropriately determined depending on the application.

As titanium oxide contained in the high refractive index layer, TiO ₂ (titanium dioxide sol) is preferably used from the viewpoint of stability of the metal oxide particle-containing composition constituting the high refractive index layer. Of TiO ₂ , rutile type is more preferable than anatase type because the high refractive index layer and the adjacent layer have high weather resistance due to low catalytic activity, and the refractive index is high.

(1) Cationic titanium oxide particles In the present invention, for example, rutile titanium dioxide particles are used as the cationic titanium oxide particles.
Rutile-type titanium dioxide particles can be prepared by the method described below.

The preparation method of rutile type titanium dioxide consists of a process (1) and a process (2).
Step (1) is a step of treating titanium dioxide hydrate with at least one basic compound selected from the group consisting of alkali metal hydroxides and alkaline earth metal hydroxides.

  Titanium dioxide hydrate can be obtained by hydrolysis of a water-soluble titanium compound such as titanium sulfate or 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, but for example, the TiO ₂ concentration is preferably 30 to 150 g / L. By setting the concentration within the 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, and sodium hydroxide, water Examples thereof include potassium oxide, magnesium hydroxide, and calcium hydroxide. 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 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.

  Moreover, as the step (2), the compound obtained in the step (1) may be treated with a carboxylic acid group-containing compound and an inorganic acid. In the production of rutile type fine particle titanium dioxide, a method of treating the compound obtained in the step (1) with an inorganic acid 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.

  In addition, 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).

  It does not specifically limit as said inorganic acid, For example, hydrochloric acid, a sulfuric acid, nitric acid etc. can be mentioned. 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.
As the order of addition, the inorganic acid may be added after the carboxylic acid group-containing compound is added, or the carboxylic acid group-containing compound may be added after the inorganic acid is added.

  For example, a carboxyl group-containing compound is added to the suspension of the compound obtained in step (1), heating is started, and an inorganic acid is added when the liquid temperature is 60 ° C. or higher, preferably 90 ° C. or higher. While maintaining the liquid temperature, the suspension of the compound obtained in the method (Method 1) and the step (1), which is preferably stirred for 15 minutes to 5 hours, more preferably 2-3 hours, When the temperature is 60 ° C. or higher, preferably 90 ° C. or higher, an inorganic acid is added, and a carboxylic acid group-containing compound is added 10 to 15 minutes after the addition of the inorganic acid, and the liquid temperature is maintained, preferably 15 minutes. The method (method 2) etc. which stir for -5 hours, More preferably 2-3 hours can be mentioned. By carrying out these methods, a suitable fine particle rutile type titanium dioxide can be obtained.

When performing the above step (2) by the above process 1, the carboxylic acid group-containing compound _is preferably one that uses 0.25～1.5Mol% to TiO 2 100 mol%, 0.4 to 0. It is more preferable to use it at a rate of 8 mol%. When the addition amount of the carboxylic acid group-containing compound is less than 0.25 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 1.5 mol. If it is more than%, rutile conversion of the particles may not proceed and anatase particles may be formed.

When performing the above step (2) by the above method 2, the carboxylic acid group-containing compound _is preferably one that uses 1.6～4.0Mol% to TiO 2 100 mol%, from 2.0 to 2. It is more preferable to use at a ratio of 4 mol%.

  When the addition amount of the carboxylic acid group-containing compound is less than 1.6 mol%, there is a possibility that 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 4.0 mol. If the amount of the carboxylic acid group-containing compound exceeds 4.0 mol%, the effect will not be good and the cost will not be improved. 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 said process (2), it is preferable to cool after completion | finish of reaction (process), and also to neutralize so that it may become pH 5.0-pH 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.

  Moreover, as a manufacturing method of titanium dioxide microparticles | fine-particles, the well-known method as described in "Titanium oxide-physical property and applied technology" (Seino Gaku pp255-258 (2000) Gihodo Publishing Co., Ltd.) etc. can be used.

  The primary particle diameter of the titanium dioxide fine particles is preferably 4 to 50 nm, more preferably 4 to 30 nm.

(2) Anionic titanium oxide particles In the present invention, as the anionic titanium oxide particles, those obtained by treating the aforementioned cationic titanium oxide particles with an anionic agent are used. For example, it can be anionized by adsorbing acrylic acid or the like to the anionic titanium oxide fine particles.

  In the present invention, the most preferable method for anionizing titanium oxide particles is a method of coating titanium oxide particles 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, and more preferably 3 to 8% by mass. This is because when the coating amount is 30% by mass or less, the desired refractive index of the high refractive index layer can be obtained, and when the coating amount is 3% or more, particles can be stably formed.

As a method of coating the titanium oxide particles with a silicon-containing hydrated oxide, a conventionally known method can be mentioned. For example, JP-A-10-158015 (Si / Al hydrated oxide treatment on rutile titanium oxide) A titanium oxide sol production method in which a hydrous oxide of silicon and / or aluminum is deposited on the surface of titanium oxide after peptization in the alkali region of the titanate cake, Japanese Patent Application Laid-Open No. 2000-204301 (rutile type) A sol in which a composite oxide of Si and Zr and / or Al is coated on titanium oxide. Hydrothermal treatment.), JP 2007-246351 (Titanium oxide hydrosol obtained by peptizing hydrous titanium oxide) And R ¹ _n SiX _4-n as a stabilizer, wherein R ¹ is a C ₁ -C ₈ alkyl group, a glycidyloxy-substituted C ₁ -C ₈ alkyl group or C _2- C ₈ alkenyl group, X is an alkoxy group, and n is 1 or 2.) A compound having a complexing action with respect to organoalkoxysilane or titanium oxide is added, and a solution of sodium silicate or silica sol in an alkaline region It is possible to refer to the matters described in, for example, a method for producing a titanium oxide hydrosol coated with a hydrous oxide of silicon by adding to pH, adjusting pH, and aging.

  The content of the anionic titanium oxide particles prepared by the above exemplified method in the high refractive index layer is preferably 15 to 70% by mass with respect to 100% by mass of the solid content of the high refractive index layer. More preferably, it is -65 mass%, and it is further more preferable that it is 30-60 mass%. It is preferable that the content of the anionic titanium oxide particles is 15 to 70% by mass in that a difference in refractive index from the low refractive index layer is imparted.

The content in the case where metal oxide particles other than cationic titanium oxide particles and anionic titanium oxide particles are contained in the high refractive index layer is particularly limited as long as the effect of the present invention can be achieved. It is not something. When metal oxide particles other than cationic and anionic titanium oxide particles are used in combination, various ionic dispersants and protective agents can be used so as not to aggregate with the titanium oxide particles. Examples of the metal oxide particles that can be used in combination include zirconium oxide, zinc oxide, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, lead titanate, red lead, yellow lead, zinc yellow, chromium oxide, Examples thereof include 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 anionic titanium oxide particles described above may be those in which the entire surface of the titanium oxide particles as the core is coated with a silicon-containing hydrated oxide, or a part of the surface of the titanium oxide particles as the core may be covered. It may be coated with a silicon-containing hydrated oxide.

<Low refractive index layer>
The low refractive index layer in the present invention comprises a coating solution containing a third water-soluble polymer and cationic silicon oxide, and a coating solution containing a fourth water-soluble polymer and anionic silicon oxide. Layers containing the third water-soluble polymer and cationic silicon oxide particles are alternately applied by spray coating, and layers containing the fourth water-soluble polymer and anionic silicon oxide particles are alternately arranged. It is laminated and configured.

In addition to the cationic silicon oxide particles, anionic silicon oxide particles, the third water-soluble polymer, and the fourth water-soluble polymer, the low refractive index layer may contain a curing agent, amino acid, and various additives as necessary. An agent or the like is selected and contained.
Further, the thickness per layer of the low refractive index layer is preferably 20 to 800 nm, and can be appropriately determined depending on the application.

  As silicon oxide constituting the low refractive index layer, silicon dioxide (silica) is preferably used, and acidic colloidal silica sol is more preferably used. Examples of silicon dioxide contained in the low refractive index layer include synthetic amorphous silica and colloidal silica.

(1) Anionic silicon oxide particles In the present invention, for example, anionic colloidal silica sol is used as the anionic silicon oxide particles.

  The colloidal silica 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, JP-A-57-14091, JP-A-60-219083, JP-A-60-219084, JP-A-61-20792, JP-A-61-188183, JP-A-63-17807, JP-A-4-93284 No. 5, JP-A-5-278324, JP-A-6-92011, JP-A-6-183134, JP-A-6-297830, JP-A-7-81214, JP-A-7-101142. , JP-A-7-179029, JP-A-7-137431, and WO94 / 26530 pamphlet. And those are.

  As such colloidal silica, a synthetic product may be used, or a commercially available product may be used. Examples of commercially available products include the Snowtex series (Snowtex OS, OXS, OS, O, etc.) sold by Nissan Chemical Industries.

(2) Cationic silicon oxide particles In the present invention, as the cationic silicon oxide particles, for example, those obtained by treating the aforementioned anionic silicon oxide particles with a cationizing agent are used.

  As the cationizing agent, for example, metal salts having cationic properties such as polyaluminum chloride, aluminum chloride, sulfuric acid band, ferric chloride, and ferric sulfate can be used. In these, metal ions charged in a cation express their aggregation ability.

  Furthermore, it is also possible to use a polyamine, for example, a cationic polymer such as DADMAC as the cationizing agent. In these, amino groups are responsible for their aggregation ability. Further, aminosilane coupling agents (N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl)- 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3- Examples thereof include aminopropyltriethoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, and the like.

<Transparent substrate>
As the transparent substrate used in the present invention, various resin films can be used. Polyolefin film (polyethylene, polypropylene, etc.), polyester film (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 constituent dicarboxylic acid components include 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 constituent components, from the viewpoint 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 transparent substrate used in the present invention is 10 to 300 μm, and preferably 20 to 150 μm. Moreover, the two transparent base materials of this invention may be piled up, In this case, the kind may be the same or different.

《Water-soluble polymer (binder)》
In the present invention, the high refractive index layer contains the first water-soluble polymer and the second water-soluble polymer, and the low refractive index layer contains the third water-soluble polymer and the fourth water-soluble polymer. Contains polymer. As these first to fourth water-soluble polymers, various water-soluble polymers described below are used as appropriate, but the first to fourth water-soluble polymers may be the same as each other. Good or different ones may be used.

In the present invention, “the water-soluble polymers are different from each other” means “the basic skeleton of the polymer is different”, “the constituent components of the polymer are different”, “the constituent components are the same and the ratio thereof is different”, “polymerization” At least one of “different in degree or molecular weight” and “different in saponification degree”. In the present invention, it is most preferable that the first to fourth water-soluble polymers are polyvinyl alcohols and have different degrees of polymerization or saponification.
In the present invention, the “same water-soluble compound” means that the basic skeleton of the polymer is the same.

Examples of the water-soluble polymer applicable to the present invention include polyvinyl alcohols, polyvinyl pyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymer, potassium acrylate-acrylonitrile copolymer, vinyl acetate-acrylic. Acrylic resin such as acid ester copolymer or acrylic acid-acrylic acid ester copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid ester copolymer, Styrene acrylic resin such as styrene-α-methylstyrene-acrylic acid copolymer or styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer, styrene-sodium styrenesulfonate copolymer, styrene-2 -Hydroxyethyl acrylate copolymer 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 Examples thereof include vinyl acetate copolymers such as polymers, vinyl acetate-maleic acid ester copolymers, vinyl acetate-crotonic acid copolymers, vinyl acetate-acrylic acid copolymers, and salts thereof. Among these, particularly preferable examples include polyvinyl alcohol, polyvinyl pyrrolidones, and copolymers containing the same.
In addition, as the water-soluble polymer applicable to the present invention, for example, natural polymers such as gelatin and thickening polysaccharide described later can be preferably used.

  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.

(1) Polyvinyl alcohol Polyvinyl alcohol preferably used in the present invention includes, in addition to ordinary polyvinyl alcohol obtained by hydrolysis of polyvinyl acetate, polyvinyl alcohol having a cation-modified terminal and anion-modified polyvinyl having an anionic group. Modified polyvinyl alcohol such as alcohol is also included.

  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-61-110483. 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, 1-dimethyl-3-dimethylaminopropyl) acrylamide and the like. The ratio of the cation-modified group-containing monomer of 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-1-2060888, as described in JP-A-61-237681 and JP-A-63-330779, 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 alcohol is, for example, a polyvinyl alcohol derivative 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-8-25595. And a block copolymer of a vinyl compound having a hydrophobic group and vinyl alcohol. Polyvinyl alcohol can be used in combination of two or more, such as the degree of polymerization and the type of modification.

(1.1) Degree of polymerization of polyvinyl alcohol Here, the degree of polymerization of polyvinyl alcohol preferably contained in the high refractive index layer and the low refractive index layer according to the present invention will be described.

In the present invention, the degree of polymerization refers to the viscosity average degree of polymerization, which is measured according to JIS-K6726 (1994). After the PVA is completely re-saponified and purified, the intrinsic viscosity [η measured in water at 30 ° C. [η ] (Dl / g) from the following equation.
P = ([η] × 10 ³ /8.29) ^{(1 / 0.62)}

In the present invention, in the formation of each refractive index layer, polyvinyl alcohol (hereinafter referred to as cationic particle coating liquid) contained in a coating liquid containing cationic particles (cationic titanium oxide particles, cationic silicon oxide particles). A coating solution containing the first water-soluble polymer and the third water-soluble polymer) and anionic particles (anionic titanium oxide particles, anionic silicon oxide particles) (hereinafter, anionic particle coating solution) The difference in the degree of polymerization is preferably 1000 or more with respect to the polyvinyl alcohol (corresponding to the second water-soluble polymer and the fourth water-soluble polymer) contained in. The difference in the degree of polymerization is more preferably 2000 or more, further preferably 2500 or more, and particularly preferably 3000 or more.
The difference in the degree of polymerization of the polyvinyl alcohol contained in the cationic particle coating solution and the polyvinyl alcohol contained in the anionic particle coating solution may be 1000 or more, and is contained in the cationic particle coating solution. The degree of polymerization of polyvinyl alcohol may be higher, or the degree of polymerization of polyvinyl alcohol contained in the anionic particle coating solution may be higher.

  As a method for comparing the difference in the degree of polymerization in each layer, when each layer contains a plurality of polyvinyl alcohol having different degrees of polymerization, the average value of the degree of polymerization of the polyvinyl alcohol contained in each layer, "polymerization degree" Adopt as. For example, when any layer contains 85% polyvinyl alcohol having a polymerization degree of 6000 and 15% polyvinyl alcohol having a polymerization degree of 3500, the polymerization degree of the polyvinyl alcohol contained in the layer is “(6000 × 0 .85) + (3500 × 0.15) = 5625 ”. In addition, the low polymerization degree polyvinyl alcohol whose polymerization degree is less than 1000 is excluded from the calculation of the polymerization degree. Modified polyvinyl alcohol is included in the calculation of the degree of polymerization.

  By making the difference in the degree of polymerization between the polyvinyl alcohol contained in the cationic particle coating solution and the polyvinyl alcohol contained in the anionic particle coating solution as described above, the disturbance (unevenness) of the interface in each layer is suppressed, The reflection characteristics can be improved.

  In addition, when the polymerization degree (average polymerization degree) of polyvinyl alcohol contained in each layer is more than 5000 and less than 6500, the bending resistance is preferably improved, more preferably 5500 to 6400, and further preferably 5600 to 6300. It is. This is because when the degree of polymerization exceeds 5000, the coating film has good bending resistance, and when it is less than 6500, the coating solution becomes stable. Moreover, it is preferable that the polymerization degree of the polyvinyl alcohol contained in the low refractive index layer is within the above range, since cracking of the coating film is suppressed.

  Further, the high refractive index layer and the low refractive index layer may further contain polyvinyl alcohol having different degrees of polymerization. As a polymerization degree (average polymerization degree) of such polyvinyl alcohol, it is preferable that it is 1500-7000, More preferably, it is 2000-6000, More preferably, it is 2300-4500. When it is 1500 or more, the crack resistance of the coating film is improved, and when it is 7000 or less, the coating solution is stabilized.

(1.2) Saponification degree of polyvinyl alcohol Next, the saponification degree of polyvinyl alcohol preferably contained in the high refractive index layer and the low refractive index layer according to the present invention will be described.

  In the present invention, the degree of saponification means the ratio of hydroxyl groups to the total number of acetyloxy groups (derived from the starting vinyl acetate) and hydroxyl groups in polyvinyl alcohol.

In the present invention, polyvinyl alcohol contained in the cationic particle coating liquid (corresponding to the first water-soluble polymer and the third water-soluble polymer) and polyvinyl alcohol contained in the anionic particle coating liquid (first The degree of saponification is preferably different from that of the second water-soluble polymer and the fourth water-soluble polymer.
By including polyvinyl alcohols having different saponification degrees, interfacial mixing is suppressed, infrared reflectance (infrared shielding rate) becomes better, and haze can be lowered. In addition, any degree of saponification of polyvinyl alcohol contained in the cationic particle coating solution and polyvinyl alcohol contained in the anionic particle coating solution may be high.

  Therefore, as a preferred embodiment, the saponification degree of polyvinyl alcohol contained in the cationic particle coating solution is different from the saponification degree of polyvinyl alcohol contained in the anionic particle coating solution.

  Furthermore, the difference in the absolute value of the saponification degree between the polyvinyl alcohol contained in the cationic particle coating solution and the polyvinyl alcohol contained in the anionic particle coating solution is preferably 3 mol% or more. More preferably, it is 5 mol% or more. By setting the difference in the absolute value of the saponification degree within the range, the interlayer mixing state of each layer can be set to a preferable level. The larger the difference in the degree of saponification between the polyvinyl alcohol contained in the cationic particle coating solution and the polyvinyl alcohol contained in the anionic particle coating solution, the better. However, from the viewpoint of solubility of polyvinyl alcohol in water, it is 20 mol% or less. It is preferable that

  When comparing the saponification degree of each polyvinyl alcohol contained in each of the high refractive index layer and the low refractive index layer, when each layer contains a plurality of types of polyvinyl alcohol having different saponification degrees, High-content polyvinyl alcohols are compared. Further, when a plurality of types of polyvinyl alcohol having different saponification degrees are contained in each layer, if the difference in the saponification degrees is within 3 mol%, they calculate the saponification degree as the same polyvinyl alcohol. However, a low polymerization degree polyvinyl alcohol having a polymerization degree of 1000 or less is not regarded as the same polyvinyl alcohol even if the difference in the saponification degree is within 3 mol%.

  Specifically, when polyvinyl alcohol having a saponification degree of 90 mol%, a saponification degree of 91 mol%, and a saponification degree of 93 mol% is contained in the same layer by 10 mass%, 40 mass%, and 50 mass%, respectively. These three polyvinyl alcohols are the same polyvinyl alcohol, and the mixture of these three is the polyvinyl alcohol contained in the layer. The “polyvinyl alcohol having a saponification degree difference of 3 mol% or less” as long as it is within 3 mol% when focusing on any polyvinyl alcohol, for example, 90, 91, 92, 94 mol% vinyl. When alcohol is included, since any polyvinyl alcohol is within 3 mol% when focusing on 91 mol% vinyl alcohol, the same polyvinyl alcohol is obtained.

When polyvinyl alcohol having a saponification degree different by 3 mol% or more is contained in the same layer, it is regarded as a mixture of different polyvinyl alcohols, and the saponification degree is calculated for each.
For example, PVA203: 5% by mass, PVA117: 25% by mass, PVA217: 10% by mass, PVA220: 10% by mass, PVA224: 10% by mass, PVA235: 20% by mass, PVA245: 20% by mass, most contained A large amount of PVA is a mixture of PVA 217 to 245 (the difference in the degree of saponification of PVA 217 to 245 is within 3 mol%, which is the same polyvinyl alcohol), and this mixture becomes the polyvinyl alcohol contained in the layer. And in the mixture of PVA217-245 (polyvinyl alcohol contained in a low refractive index layer or a high refractive index layer), a saponification degree will be 88%. Further, the modified polyvinyl alcohol is included in the calculation of the saponification degree.

In addition, the saponification degree of polyvinyl alcohol contained in each layer is preferably 75 mol% or more from the viewpoint of solubility in water.
Further, the interlayer mixing of each layer is such that one of the polyvinyl alcohol contained in the cationic particle coating solution and the polyvinyl alcohol contained in the anionic particle coating solution has a saponification degree of 90 mol% or more and the other is 90 mol% or less. It is preferable to bring the state to a desirable level.
Moreover, it is more preferable that one of the polyvinyl alcohol contained in the cationic particle coating solution and the polyvinyl alcohol contained in the anionic particle coating solution has a saponification degree of 95 mol% or more and the other is 90 mol% or less.
In addition, although the upper limit of the saponification degree of polyvinyl alcohol is not specifically limited, Usually, it is less than 100 mol% and is about 99.9 mol% or less.

(2) Gelatin In the optical film according to the present invention, gelatin can also be used as the water-soluble polymer. As gelatin used in the present invention, in addition to lime-processed gelatin, acid-processed gelatin may be used, and further, a hydrolyzate of gelatin and an enzyme-decomposed product of gelatin can be used. These water-swellable polymers may be used alone or in a plurality of types.
In the present invention, when gelatin is used as the first to fourth water-soluble polymers, the gelatin contained in the cationic particle coating solution (the first water-soluble polymer and the third water-soluble polymer). Equivalent) and gelatin contained in the anionic particle coating solution (corresponding to the second water-soluble polymer and the fourth water-soluble polymer) preferably have different properties. For example, molecular weight, polymerization degree, etc. are mentioned.

(3) Thickening polysaccharide Moreover, in the optical film which concerns on this invention, a thickening polysaccharide can also be used as a water-soluble polymer. Examples of the thickening polysaccharide used in the present invention include generally known natural simple polysaccharides, natural complex polysaccharides, synthetic simple polysaccharides and synthetic complex polysaccharides. Details of these polysaccharides Can refer to “Biochemical Encyclopedia (2nd edition), Tokyo Chemical Doujin Publishing”, “Food Industry”, Vol. 31 (1988), p. 21.

  In the present invention, the thickening polysaccharide is a polymer of saccharides and has a large number of hydrogen bonding groups in the molecule, and due to the difference in hydrogen bonding strength between molecules due to temperature, the viscosity difference at low temperature and the viscosity at high temperature. Is a polysaccharide having a large characteristic, and when metal oxide fine particles are added, the viscosity is increased due to hydrogen bonding with the metal oxide fine particles at low temperatures. As the viscosity increase range, the viscosity at 40 ° C. increases by 1.0 mPa · s or more when added, preferably 5.0 mPa · s or more, more preferably 10.0 mPa · s or more. Has a rising ability.

  Examples of the thickening polysaccharide applicable to the present invention include β1-4 glucan (eg, carboxymethylcellulose, carboxyethylcellulose, etc.), galactan (eg, agarose, agaropectin, etc.), galactomannoglycan (eg, locust bean gum). , Guaran, etc.), xyloglucan (eg, tamarind gum, etc.), glucomannoglycan (eg, salmon mannan, wood-derived glucomannan, xanthan gum, etc.), galactoglucomannoglycan (eg, softwood-derived glycan), arabino Galactoglycan (for example, soybean-derived glycan, microorganism-derived glycan, etc.), Glucarnoglycan (for example, gellan gum), glycosaminoglycan (for example, hyaluronic acid, keratan sulfate, etc.), alginic acid and alginate, agar, κ -Natural polymer polysaccharides derived from red algae such as carrageenan, λ-carrageenan, ι-carrageenan, fur celerane and the like, preferably from the viewpoint of not reducing the dispersion stability of the metal oxide fine particles coexisting in the coating solution The structural unit preferably has no carboxylic acid group or 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.

  In the present invention, it is further preferable to use two or more thickening polysaccharides in combination.

  The content of the thickening polysaccharide as the water-soluble polymer in each refractive index layer is preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less. However, when used in combination with other water-soluble polymers or emulsion resins, it may be contained in an amount of 3% by mass or more. When there are few thickening polysaccharides, the film surface will be disordered at the time of drying of a coating film, and the tendency for transparency to deteriorate will become large. On the other hand, if the content is 50% by mass or less, the relative content of the metal oxide becomes appropriate, and it becomes easy to increase the difference in refractive index between the high refractive index layer and the low refractive index layer.

《Curing agent》
In the optical film according to the present invention, it is preferable to use a curing agent in order to cure the water-soluble polymer as a binder.

  The curing agent applicable to the present invention is not particularly limited as long as it causes a curing reaction with a water-soluble polymer. When the water-soluble polymer is polyvinyl alcohol, boric acid and its salts are preferable, but other known ones can be used, and generally a compound having a group capable of reacting with the water-soluble polymer or a water-soluble polymer. It is a compound that promotes the reaction between different groups of the polymer, and it is appropriately selected according to the type of the water-soluble polymer. 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 vinyl sulfone 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.

"amino acid"
In the present invention, an amino acid is preferably further added for the purpose of improving the dispersibility of the metal oxide.

  The amino acid referred to in the present invention is a compound having an amino group and a carboxyl group in the same molecule, and may be any type of amino acid such as α-, β-, and γ-, but has an isoelectric point of 6.5 or less. It is preferably an amino acid. Some amino acids have optical isomers, but in the present invention, there is no difference in effect due to optical isomers, and any isomer having an isoelectric point of 6.5 or less is used alone or in racemic form. be able to.

  For a detailed explanation of amino acids applicable to the present invention, reference can be made to the descriptions of pages 268 to 270 of the Chemical Dictionary 1 (reprinted edition, published in 1960).

  In the present invention, preferred amino acids include glycine, alanine, valine, α-aminobutyric acid, γ-aminobutyric acid, β-alanine, serine, ε-amino-n-caproic acid, leucine, norleucine, phenylalanine, threonine, asparagine, asparagine. Examples include acid, histidine, lysine, glutamine, cysteine, methionine, proline, hydroxyproline, etc. For use as an aqueous solution, the solubility at the isoelectric point is preferably 3 g or more with respect to 100 g of water. Glycine, alanine, serine, histidine, lysine, glutamine, cysteine, methionine, proline, hydroxyproline, etc. are preferably used, and from the viewpoint that the metal oxide particles have a gentle hydrogen bond with the binder, serine, hydride having a hydroxyl group. It is more preferable to use a Kishipurorin.

<< Other Additives Contained in High Refractive Index Layer and Low Refractive Index Layer >>
The high refractive index layer and the low refractive index layer according to the present invention may contain various additives as necessary.

  For example, 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, and JP-A-60-72785. No. 61-146591, JP-A-1-95091, JP-A-3-13376, etc., various surfactants of anion, cation or nonion, JP-A-59- 42993, 59-52689, 62-280069, 61-242871, and JP-A-4-219266, etc., whitening agents such as sulfuric acid, phosphoric acid, acetic acid, PH adjusters such as citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate, antifoaming agents, lubricants such as diethylene glycol, preservatives, Antistatic agents, can also contain various known additives such as a matting agent.

<< Optical film manufacturing method >>
With reference to FIG. 1, the manufacturing method of the optical film which concerns on this invention is demonstrated. FIG. 1 is a schematic configuration diagram showing a manufacturing apparatus 100 for manufacturing an optical film according to the present invention.

  The manufacturing apparatus 100 includes a first film forming unit 10 and a second film forming unit 20. The first film forming unit 10 forms a high refractive index layer on the transparent substrate 2 to form a second forming layer. A low refractive index layer is formed on the transparent substrate 2 by the film unit 20. The manufacturing apparatus 100 manufactures an optical film by alternately laminating a plurality of high refractive index layers and low refractive index layers on the transparent substrate 2.

  The first film forming unit 10 is formed on the transparent substrate 2 by alternately applying a coating liquid containing cationic titanium oxide particles and a coating liquid containing anionic titanium oxide particles by spray coating. A refractive index layer is formed.

  For example, as shown in FIG. 1, the first film forming unit 10 includes a control unit 11, a cationic titanium oxide particle supply unit 12, an anionic titanium oxide particle supply unit 13, nozzles 14a and 14b, a support unit 15 and the like. It is configured.

  The control unit 11 includes a CPU, a RAM, a non-volatile memory, and the like, and controls the operation of each unit of the first film forming unit 10 by reading and executing a control program stored in the non-volatile memory. For example, the control unit 11 controls the amount of liquid fed from the cationic titanium oxide particle supply unit 12 and the anionic titanium oxide particle supply unit 13 to the nozzles 14a and 14b.

The cationic titanium oxide particle supply unit 12 stores the coating liquid containing the cationic titanium oxide particles, and sends the stored coating liquid to the nozzle 14a by the pressure of nitrogen gas, from the nozzle 14a to the transparent substrate 2. Spray towards. The amount of the coating liquid sprayed from the cationic titanium oxide particle supply unit 12 is appropriately set by the control unit 11.
The coating liquid stored in the cationic titanium oxide particle supply unit 12 is obtained by dispersing the above-described cationic titanium oxide particles in water, an organic solvent, or a mixed solvent thereof. This coating solution contains a water-soluble polymer, and a curing agent, an amino acid, various additives, and the like are selected and contained as necessary.

The anionic titanium oxide particle supply unit 13 stores a coating liquid containing anionic titanium oxide particles, sends the stored coating liquid to the nozzle 14b by the pressure of nitrogen gas, and directs the coating liquid from the nozzle 14b toward the transparent substrate 2. Spray. The amount of coating liquid sprayed from the anionic titanium oxide particle supply unit 13 is appropriately set by the control unit 11.
The coating liquid stored in the anionic titanium oxide particle supply unit 13 is obtained by dispersing the above-described anionic titanium oxide particles in water, an organic solvent, a mixed solvent thereof or the like. This coating solution contains a water-soluble polymer, and a curing agent, an amino acid, various additives, and the like are selected and contained as necessary.

The nozzles 14a and 14b spray the coating liquid supplied from the cationic titanium oxide particle supply unit 12 and the anionic titanium oxide particle supply unit 13 from the spraying port.
As a method for spraying the solution, a known method can be used, and is not particularly limited, and examples thereof include an ultrasonic method, a two-fluid method, and a rotary method in which the solution is atomized using an ultrasonic vibrator.

  The distance from the spray ports of the nozzles 14a and 14b to the film formation surface of the transparent substrate 2 is appropriately set according to the amount of coating liquid fed, the solid content concentration, and the like. The coating solution sprayed from the nozzles 14a and 14b gradually evaporates the solvent until it reaches the transparent substrate 2, and the solid content concentration increases to increase the viscosity of the solution. The longer the distance from the spray port to the transparent substrate 2, the more widely the coating solution diffuses and the productivity is improved. However, since the solvent easily evaporates and the solid concentration tends to increase, the wetness on the transparent substrate 2 is increased. In some cases, it may be difficult to form a uniform film.

  The first film forming unit 10 configured as described above further includes a drive unit (not shown), and is configured to change the relative position between the transparent substrate 2 and the nozzles 14a and 14b.

  The second film forming unit 20 is formed by alternately applying a coating solution containing cationic silicon oxide particles and a coating solution containing anionic silicon oxide particles on the transparent substrate 2 by spray coating. A refractive index layer is formed.

  As shown in FIG. 1, for example, the second film forming unit 10 includes a control unit 21, a cationic silicon oxide particle supply unit 22, an anionic silicon oxide particle supply unit 23, nozzles 24a and 24b, a support unit 25, and the like. It is configured. Each part constituting the second film forming unit 10 is configured in substantially the same manner as the first film forming unit 10 described above, and is stored in the cationic silicon oxide particle supply unit 22 and the anionic silicon oxide particle supply unit 23. The coating solution is different in that the coating solution contains cationic silicon oxide particles and anionic silicon oxide particles.

  A method for manufacturing an optical film by the manufacturing apparatus 100 configured as described above will be described below.

First, the transparent substrate 2 is installed on the support unit 25 of the second film forming unit 20.
The second film forming unit 20 sprays the coating liquid fed from the cationic silicon oxide particle supply unit 22 from the nozzle 24a toward the transparent substrate 2, and the cationic silicon oxide particle-containing layer is formed on the transparent substrate 2. Form. And the 2nd film-forming part 20 sprays the coating liquid sent from the anionic silicon oxide particle supply part 23 toward the transparent base material 2 from the nozzle 24b, and anionic silicon oxide particles on the transparent base material 2 A containing layer is formed. The second film forming unit 20 alternates the formation process of the cationic silicon oxide particle-containing layer and the formation process of the anionic silicon oxide particle-containing layer until a layer having a desired thickness is formed on the transparent substrate 2. Repeat. Thereby, a low refractive index layer having a desired thickness is formed on the transparent substrate 2.
In addition, the transparent base material 2 may be left for a predetermined time to dry the surface of the transparent base material 2 between the step of forming the cationic silicon oxide particle-containing layer and the step of forming the anionic silicon oxide particle-containing layer. .

Subsequently, the transparent substrate 2 on which the low refractive index layer is formed is placed on the support unit 15 of the first film forming unit 10.
The first film forming unit 10 sprays the coating liquid fed from the cationic titanium oxide particle supply unit 12 from the nozzle 14a toward the transparent substrate 2, and the cationic titanium oxide particle-containing layer is formed on the transparent substrate 2. Form. And the 1st film-forming part 10 sprays the coating liquid sent from the anionic titanium oxide particle supply part 13 toward the transparent base material 2 from the nozzle 14b, and anionic titanium oxide particles on the transparent base material 2 A containing layer is formed. The first film forming unit 10 alternates the formation process of the cationic titanium oxide particle-containing layer and the formation process of the anionic titanium oxide particle-containing layer until a layer having a desired thickness is formed on the transparent substrate 2. Repeat. Thereby, a high refractive index layer having a desired thickness is formed on the transparent substrate 2.
In addition, between the formation process of the cationic titanium oxide particle-containing layer and the formation process of the anionic titanium oxide particle-containing layer, the transparent substrate 2 may be left for a predetermined time to dry the surface of the transparent substrate 2. .

Furthermore, the manufacturing apparatus 100 performs a process of forming a low refractive index layer by the second film forming unit 20 and a process by the first film forming unit 10 until an optical interference film having a desired thickness is formed on the transparent substrate 2. The step of forming the refractive index layer is repeated.
In this way, the optical film is manufactured by the manufacturing apparatus 100.

In the above description, the optical film manufacturing method according to the present invention is performed using the manufacturing apparatus 100. However, the coating liquid containing the first water-soluble polymer and the cationic silicon oxide particles, A coating solution containing two water-soluble polymers and anionic silicon oxide particles is alternately spray-coated to form a high refractive index layer, and a third water-soluble polymer and cationic titanium oxide particles are formed. If the low refractive index layer is formed by alternately spraying the coating liquid containing and the coating liquid containing the fourth water-soluble polymer and anionic titanium oxide particles, the production shown in FIG. It may be performed without using the device 100.
In the above description, the low refractive index layer is first formed on the transparent substrate and then the high refractive index layer is formed. However, after the high refractive index layer is formed first, the low refractive index layer is formed. It is good also as what forms.

《Optical reflection film》
When the optical reflective film of the present invention is used as a heat-shielding film, a multilayer film is formed by laminating films having different refractive indexes on a polymer film by simultaneous multilayer coating, and in the visible light region shown in JIS R3106-1998. It is preferable to design the optical film thickness and unit so that the transmittance is 50% or more and the region having a wavelength of 900 nm to 1400 nm has a region exceeding the reflectance of 40%.

  In the thermal barrier film, the infrared region of the incident spectrum of the direct sunlight is related to the increase in the indoor temperature, and by blocking this, the increase in the indoor temperature can be suppressed. Looking at the cumulative energy ratio from the shortest infrared wavelength (760 nm) to the longest wavelength 3200 nm based on the weight coefficient described in Japanese Industrial Standards JIS R3106, the entire infrared region from the wavelength 760 nm to the longest wavelength 3200 nm Looking at the cumulative energy from 760 nm to each wavelength when the total energy is 100, the total energy from 760 to 1300 nm occupies about 75% of the entire infrared region. Therefore, shielding the wavelength region up to 1300 nm has the most efficient energy saving effect by heat ray shielding.

  When the reflectance in the near-infrared region (760 to 1300 nm) is about 80% or more at the maximum peak value, a decrease in body temperature can be obtained by sensory evaluation. For example, the temperature at the window facing southeast in the morning of August showed a clear difference when the reflectance in the near infrared region was shielded to about 80% at the maximum peak value.

  As a result of obtaining a multilayer film structure necessary for developing such a function by optical simulation (FTG Software Associates Film DESIGN Version 2.23.3700), a high refraction of 1.9 or more, desirably 2.0 or more. It has been found that excellent characteristics can be obtained when six or more layers are laminated using a rate layer. For example, looking at the simulation results of a model in which eight layers of high refractive index layers and low refractive index layers (refractive index = 1.35) are alternately stacked, the reflectance is 70 when the refractive index of the high refractive index layer is 1.8. However, the reflectance of about 80% can be obtained at 1.9. Further, in the model in which the high refractive index layer (refractive index = 2.2) and the low refractive index layer (refractive index = 1.35) are alternately stacked, the reflectance does not reach 60% when the number of stacked layers is 4. However, when there are 6 layers, a reflectance of about 80% can be obtained.

  Since the wavelength of the reflected light can be controlled by changing the optical film thickness in this way, in the unit in which the high refractive index layer and the low refractive index layer are alternately laminated, the high refractive index layer and the low refractive index layer With a configuration in which a plurality of units having different optical film thicknesses are stacked, the range of the reflected light is widened, and a thermal barrier film that reflects not only the near infrared but also part of the infrared or visible light region and can do.

Similarly, the optical film according to the present invention may be configured as an ultraviolet light reflecting film that changes the reflectance by controlling the optical film thickness of the high refractive index layer and the low refractive index layer and cuts ultraviolet light. Alternatively, it may be configured as an antireflection film that reduces the reflectance by optical interference.
As an example when it is configured as an antireflection film,
Transparent substrate / low refraction (refractive index 1.46, film thickness 94 nm) / medium refraction (refractive index 1.62, film thickness 170 nm) / high refraction (refractive index 2.00, film thickness 138 nm) / low refraction (refraction) (Rate 1.38, film thickness 94 nm)
Transparent substrate / medium refraction (refractive index 1.70, film thickness 76 nm) / high refraction (refractive index 2.00, film thickness 130 nm) / low refraction (refractive index 1.38, film thickness 94 nm)
And the like.

<Application of optical reflective film>
The optical reflective film of the present invention can be applied to a wide range of fields. For example, film for window pasting such as heat ray reflecting film that gives heat ray reflection effect, film for agricultural greenhouses, etc. Etc., mainly for the purpose of improving the weather resistance. In particular, it is suitable for a member in which the optical external reflection film according to the present invention is bonded to a substrate such as glass or a glass substitute resin directly or via an adhesive.

  The adhesive is placed so that the near-infrared reflective film is on the sunlight (heat ray) incident surface side when bonded to a window glass or the like. Moreover, when a near-infrared reflective film is pinched | interposed between a window glass and a base material, it can seal from surrounding gas, such as a water | moisture content, and is preferable for durability. Even if the near-infrared reflective film of the present invention is installed outdoors or outside the vehicle (for external application), it is preferable because of environmental durability.

  As an adhesive applicable to the present invention, an adhesive mainly composed of a photocurable or thermosetting resin can be used.

  The adhesive preferably has durability against ultraviolet rays, and is preferably an acrylic adhesive or a silicone adhesive. Furthermore, an acrylic adhesive is preferable from the viewpoint of adhesive properties and cost. In particular, since the peel strength can be easily controlled, a solvent system is preferable among the solvent system and the emulsion system in the acrylic adhesive. When a solution polymerization polymer is used as the acrylic solvent-based pressure-sensitive adhesive, known monomers can be used as the monomer.

  Moreover, you may use the polyvinyl butyral resin used as an intermediate | middle layer of a laminated glass, or ethylene-vinyl acetate copolymer type resin. 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]. In addition, you may add and mix | blend an ultraviolet absorber, an antioxidant, an antistatic agent, a heat stabilizer, a lubricant, a filler, coloring, an adhesion regulator etc. suitably in an adhesion layer.

  Further, a metal oxide can be used as a light absorbing material that absorbs light other than the reflection band. Metal oxides include 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). ATO and ITO are particularly preferable.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

  First, coating solutions L1 to L5 for a low refractive index layer containing anionic silicon oxide were prepared as follows.

(Preparation of coating liquid L1 for low refractive index layer)
Colloidal silica (Snowtex OXS, manufactured by Nissan Chemical Industries, Ltd., solid content: 10% by mass) and 5.5 parts by mass of polyvinyl alcohol (PVA-217, polymerization degree: 1700, saponification degree: 88.0 mol%, manufactured by Kuraray Co., Ltd.) After adding 0.2 parts by weight of a 3% by weight aqueous solution and 1 part by weight of a 3% by weight aqueous boric acid solution, while heating to 45 ° C. and stirring, polyvinyl alcohol (PVA-217, polymerization degree 1700, saponification degree 88.0 mol) 2 parts by weight of a 5% by weight aqueous solution (made by Kuraray Co., Ltd.) and 0.1 parts by weight of a 1% by weight aqueous solution of an anionic surfactant (Rapidol A30, made by NOF Corporation). In addition, a coating solution L1 for a low refractive index layer was prepared.

(Preparation of coating liquid L2 for low refractive index layer)
Instead of a 5 mass% aqueous solution of polyvinyl alcohol (PVA-217, polymerization degree 1700, saponification degree 88.0 mol%, manufactured by Kuraray Co., Ltd.), polyvinyl alcohol (PVA-417, polymerization degree 1700, saponification degree 79.5 mol%, Kuraray) A low-refractive-index layer coating solution L2 was prepared in the same manner as the low-refractive-index layer coating solution L1 except that a 5% by mass aqueous solution (manufactured by Komatsu) was used.

(Preparation of coating liquid L3 for low refractive index layer)
Instead of a 5 mass% aqueous solution of polyvinyl alcohol (PVA-217, polymerization degree 1700, saponification degree 88.0 mol%, manufactured by Kuraray Co., Ltd.), polyvinyl alcohol (PVA-245, polymerization degree 4500, saponification degree 88.0 mol%, Kuraray) A low-refractive-index layer coating solution L3 was prepared in the same manner as the low-refractive-index layer coating solution L1 except that a 5% by mass aqueous solution (manufactured by Komatsu) was used.

(Preparation of coating liquid L4 for low refractive index layer)
Instead of 5 mass% aqueous solution of polyvinyl alcohol (PVA-217, polymerization degree 1700, saponification degree 88.0 mol%, manufactured by Kuraray Co., Ltd.), 5 mass% of acid-treated gelatin (high molecular weight gelatin) having a weight average molecular weight of 130,000 A low refractive index layer coating liquid L4 was prepared in the same manner as the low refractive index layer coating liquid L1 except that the aqueous solution was used.

(Preparation of coating liquid L5 for low refractive index layer)
Instead of a 5 mass% aqueous solution of polyvinyl alcohol (PVA-217, polymerization degree 1700, saponification degree 88.0 mol%, manufactured by Kuraray Co., Ltd.), a low molecular weight gelatin having a weight average molecular weight of 20,000 hydrolyzed by alkali treatment A low refractive index layer coating liquid L5 was prepared in the same manner as the low refractive index layer coating liquid L1 except that a 5 mass% aqueous solution was used.

  Subsequently, coating solutions L6 and L7 for low refractive index layer containing cationic silicon oxide were prepared as follows.

(Preparation of coating liquid L6 for low refractive index layer)
0.92 parts of a 23.5% by weight aqueous solution of polyaluminum chloride (manufactured by Taki Chemical; Takibine # 1500) as a cationizing agent, and 34 parts of a 15% by weight aqueous solution of colloidal silica (manufactured by Nissan Chemical Co., Ltd .; Snowtex OUP) After mixing 10.34 parts of a 5.5% by weight aqueous solution of boric acid and 0.48 part of a 2.1% by weight aqueous solution of lithium hydroxide, the mixture was dispersed using a high-pressure homogenizer disperser. After dispersion, it was finished to 1000 parts with pure water to prepare a silicon oxide dispersion.

  Next, the prepared silicon oxide dispersion was heated to 45 ° C., and 460 parts of pure water, a 4.0 mass% aqueous solution of polyvinyl alcohol (PVA-217, polymerization degree 1700, saponification degree 88.0 mol%, manufactured by Kuraray Co., Ltd.) 40 0.55 parts of a 5% by weight aqueous solution of a quaternary ammonium salt-based cationic surfactant (Nissan Cation-2-DB-500E manufactured by NOF Corporation) was added to the low refractive index layer. A coating liquid L6 was prepared.

(Preparation of coating solution L7 for low refractive index layer)
Instead of a 4.0 mass% aqueous solution of polyvinyl alcohol (PVA-217, polymerization degree 1700, saponification degree 88.0 mol%, manufactured by Kuraray Co., Ltd.), 5 of acid-treated gelatin (high molecular weight gelatin) having a weight average molecular weight of 130,000 A coating liquid L7 for a low refractive index layer was prepared in the same manner as the coating liquid L6 for a low refractive index layer except that a mass% aqueous solution was used.

  Subsequently, coating solutions H1 to H6 for high refractive index layer containing anionic titanium oxide were prepared as follows.

(Preparation of coating liquid H1 for high refractive index layer)
1 kg of titanium oxide sol (SRD-W, volume average particle size 5 nm, rutile titanium dioxide particles, manufactured by Sakai Chemical Co., Ltd.) diluted to 10.0% by mass with 0.5 kg of titanium oxide sol aqueous dispersion and 2 kg of pure water And then heated to 90 ° C. Next, 1.3 kg of an aqueous silicic acid solution was gradually added, followed by heat treatment at 175 ° C. for 18 hours in an autoclave, further concentrated to titanium oxide having a rutile structure, and the coating layer was made of SiO ₂ . Some 20 mass% particles were obtained.

  28.9 parts of a 20% by weight titanium oxide particle sol aqueous dispersion obtained as described above, 10.5 parts of a 1.92% by weight aqueous citric acid solution, and 4% by weight polyvinyl alcohol (PVA-217). And a polymerization degree 1700, a saponification degree 88.0 mol%, manufactured by Kuraray Co., Ltd.) 2.0 parts aqueous solution and 9.0 parts 3% by weight boric acid aqueous solution were mixed to prepare a titanium oxide particle dispersion.

  Next, while stirring the titanium oxide particle dispersion, 41.9% by weight of 4% polyvinyl alcohol (PVA-217, polymerization degree 1700, saponification degree 88.0 mol%, manufactured by Kuraray Co., Ltd.) 41.9% in pure water 16.3 parts. Parts were added. Further, 0.5 part of a 1% by mass aqueous solution of an anionic surfactant (Nippon Rapisol A30) was added, and finally it was made up to 1500 parts with pure water to prepare a coating solution H1 for a high refractive index layer.

(Preparation of coating liquid H2 for high refractive index layer)
Instead of a 4 mass% aqueous solution of polyvinyl alcohol (PVA-217, polymerization degree 1700, saponification degree 88.0 mol%, manufactured by Kuraray Co., Ltd.), polyvinyl alcohol (PVA-417, polymerization degree 1700, saponification degree 79.5 mol%, Kuraray) A high-refractive-index layer coating solution H2 was prepared in the same manner as the high-refractive-index layer coating solution H1 except that a 4% by mass aqueous solution (manufactured by Kogyo Co., Ltd.) was used.

(Preparation of coating liquid H3 for high refractive index layer)
Instead of a 4 mass% aqueous solution of polyvinyl alcohol (PVA-217, polymerization degree 1700, saponification degree 88.0 mol%, manufactured by Kuraray Co., Ltd.), polyvinyl alcohol (PVA-245, polymerization degree 4500, saponification degree 88.0 mol%, Kuraray) A high-refractive-index layer coating solution H3 was prepared in the same manner as the high-refractive-index layer coating solution H1 except that a 4% by mass aqueous solution (manufactured by Kogyo Co., Ltd.) was used.

(Preparation of coating liquid H4 for high refractive index layer)
4% by mass of acid-treated gelatin (high molecular weight gelatin) having a weight average molecular weight of 130,000 instead of a 4% by mass aqueous solution of polyvinyl alcohol (PVA-217, polymerization degree 1700, saponification degree 88.0 mol%, manufactured by Kuraray Co., Ltd.) A high refractive index layer coating solution H4 was prepared in the same manner as the high refractive index layer coating solution H1 except that the aqueous solution was used.

(Preparation of coating liquid H5 for high refractive index layer)
Instead of a 4% by weight aqueous solution of polyvinyl alcohol (PVA-217, polymerization degree 1700, saponification degree 88.0 mol%, manufactured by Kuraray Co., Ltd.), a low molecular weight gelatin having a weight average molecular weight of 20,000 hydrolyzed by alkali treatment A coating liquid H5 for a high refractive index layer was prepared in the same manner as the coating liquid H1 for a high refractive index layer, except that a 4% by mass aqueous solution was used.

(Preparation of coating liquid H6 for high refractive index layer)
15.0 mass% titanium oxide sol (SRD-W, volume average particle size 5 nm, rutile titanium dioxide particles, manufactured by Sakai Chemical Co., Ltd.) 40 mass% polyacrylic acid (Julimer AC-10S, manufactured by Toagosei Co., Ltd.) 1.13 parts by mass was added and stirred for 5 hours to obtain a titanium oxide sol coated with polyacrylic acid.
Coating layer instead of the titanium oxide sol is SiO _2, except that the coating layer is used titanium oxide sol is polyacrylic acid preparing high refractive index layer coating solution H6 in the same manner as the high-refractive index layer coating solution H1 did.

  Subsequently, coating liquids H7 and H8 for high refractive index layer containing cationic titanium oxide were prepared as follows.

(Preparation of coating liquid H7 for high refractive index layer)
15.0 mass% titanium oxide sol (SRD-W, volume average particle size 5 nm, rutile titanium dioxide particles, Sakai Chemical Co., Ltd.) 80 mass parts, polyvinyl alcohol (PVA-217, polymerization degree 1700, saponification degree 88.0 mol) 80% by mass of a 5% by mass aqueous solution of Kuraray Co., Ltd.) and 0.45 parts by mass of a 5.0% by mass aqueous surfactant solution (Cotamine 24P, quaternary ammonium salt cationic surfactant, manufactured by Kao Corporation) And finished to 2400 parts by mass with pure water, and further adjusted so that the film surface pH of the coating film becomes 5.0 using boric acid / borax to prepare a coating solution H7 for a high refractive index layer. .

(Preparation of coating liquid H8 for high refractive index layer)
Instead of 5 mass% aqueous solution of polyvinyl alcohol (PVA-217, polymerization degree 1700, saponification degree 88.0 mol%, manufactured by Kuraray Co., Ltd.), 5 mass% of acid-treated gelatin (high molecular weight gelatin) having a weight average molecular weight of 130,000 A high refractive index layer coating solution H8 was prepared in the same manner as the high refractive index layer coating solution H7 except that the aqueous solution was used.

  Using the coating solutions L1 to L7 for the low refractive index layer and the coating solutions H1 to H8 for the high refractive index layer prepared as described above, the following optical films (infrared reflective films) 101 to 108 were produced.

(Preparation of infrared reflective film 101)
On a polyethylene terephthalate film (Toyobo A4300, double-sided easy-adhesion layer) having a thickness of 50 μm, a coating solution containing a low refractive index layer as a coating solution containing cationic silicon oxide particles and a coating containing anionic silicon oxide particles The coating liquid L1 for the low refractive index layer as a liquid is spray-applied alternately with the coating amount adjusted so that the dry film thickness is 21 nm and a total of 42 nm, respectively, and this is repeated three times to reduce the low refractive index of 126 nm. A layer was formed.

  On the formed low refractive index layer, a coating liquid H7 for a high refractive index layer as a coating liquid containing cationic titanium oxide particles, and a coating liquid H1 for a high refractive index layer as a coating liquid containing anionic titanium oxide particles. The coating thickness was adjusted so that the dry film thickness was 21 nm and the total thickness was 42 nm, respectively, and spray coating was alternately performed. This was repeated three times to form a 126 nm high refractive index layer.

  By repeating these operations, a multi-layer coated product consisting of a total of 9 layers each consisting of 5 low refractive index layers and 4 high refractive index layers was produced.

(Preparation of infrared reflective film 102)
The same as the infrared reflective film 101 except that the coating liquid L1 for the low refractive index layer is changed to the coating liquid L2 for the low refractive index layer and the coating liquid H1 for the high refractive index layer is changed to the coating liquid H2 for the high refractive index layer. Thus, an infrared reflective film 102 was produced.

(Preparation of infrared reflective film 103)
The same as the infrared reflective film 101 except that the coating liquid L1 for the low refractive index layer is changed to the coating liquid L3 for the low refractive index layer and the coating liquid H1 for the high refractive index layer is changed to the coating liquid H3 for the high refractive index layer. Thus, an infrared reflective film 103 was produced.

(Preparation of infrared reflective film 104)
The coating liquid L6 for the low refractive index layer is changed to the coating liquid L7 for the low refractive index layer, the coating liquid L1 for the low refractive index layer is changed to the coating liquid L4 for the low refractive index layer, and the coating liquid H7 for the high refractive index layer. Is changed to the coating liquid H8 for the high refractive index layer, and the infrared reflecting film 104 is the same as the infrared reflecting film 101 except that the coating liquid H1 for the high refractive index layer is changed to the coating liquid H4 for the high refractive index layer. Was made.

(Preparation of infrared reflective film 105)
The same as the infrared reflective film 104 except that the coating liquid L4 for the low refractive index layer is changed to the coating liquid L5 for the low refractive index layer and the coating liquid H4 for the high refractive index layer is changed to the coating liquid H5 for the high refractive index layer. Thus, an infrared reflective film 105 was produced.

(Preparation of infrared reflective film 106)
The same as the infrared reflective film 101 except that the coating liquid L1 for the low refractive index layer is changed to the coating liquid L4 for the low refractive index layer and the coating liquid H1 for the high refractive index layer is changed to the coating liquid H4 for the high refractive index layer. Thus, an infrared reflective film 106 was produced.

(Preparation of infrared reflection film 107)
An infrared reflective film 107 was produced in the same manner as the infrared reflective film 101 except that the high refractive index layer coating liquid H1 was changed to the high refractive index layer coating liquid H6.

(Preparation of infrared reflective film 108 (comparative example))
A 100 μm thin film glass was prepared. A low refractive index layer and a high refractive index layer were formed on the thin film glass by the method described in Non-Patent Document 1. That is, PAH (Poly (allylamine hydrochloride)) / SiO ₂ is laminated 20 times on a thin film glass to form a low refractive index layer, and TiO ₂ / PVS (poly (vinyl sulfonic acid sodium salt)) is laminated 20 times. Thus, a high refractive index layer was formed.
PAH used was Mw = 70000, manufactured by Sigma Aldrich. For SiO ₂ , colloidal silica (Snowtex OXS, solid content 10 mass%) manufactured by Nissan Chemical Industries, Ltd. was used. PVS is Mw = 1700, made by Sigma Aldrich (solid content 25% aqueous solution), TiO ₂ is a titanium oxide sol made by Sakai Chemical Co., Ltd. (SRD-W, volume average particle size 5 nm, rutile titanium dioxide particles, solid content 15%) Was used.

  This operation was repeated to form a film consisting of a total of 9 layers of 5 low refractive index layers and 4 high refractive index layers alternately. After lamination, this sample was baked at 550 ° C. for 2 hours to remove the polymer compound. Various conditions were adjusted so that the total film thickness after firing was 126 nm.

(Evaluation of infrared reflective films 101-108)
The following evaluation was performed about each infrared reflective film produced as mentioned above. The evaluation results are shown in Table 1.

(1) Bending resistance (crack)
The process of winding the prepared infrared reflective film around a cylinder having a diameter of 10 cm and returning it was repeated 10 times, and the state of the film was confirmed with a microscope at a magnification of 50 times. The evaluation results are shown by the following criteria.
×: 6 or more cracks in 1 field of view Δ: 1 to 5 cracks in 1 field of view ○: No crack

(2) Bending resistance (reflection characteristics)
Using a spectrophotometer (using an integrating sphere, manufactured by Hitachi, Ltd., U-4000 type), the transmittance in the region of 700 nm to 2000 nm of the infrared reflective films 101 to 107 subjected to the above bending resistance (crack) evaluation was measured. did. The average transmittance of 700 to 2000 nm was determined, and the ratio to the infrared reflective film 107 was determined. The smaller this ratio, the better the infrared reflection after the bending resistance than the comparison. The evaluation results are shown by the following criteria.
×: 1 or more △; 0.9 or more and less than 1
○: 0.7 or more and less than 0.8 ○; 0.6 or more and less than 0.7 ◎; less than 0.6 In addition, the infrared reflective film 108 has a large number of cracks due to the bending resistance (cracks) described above, The reflection characteristics could not be evaluated.

(3) Summary As is apparent from Table 1, the infrared reflective films 101 to 107 according to the present invention have no occurrence of cracks or the like even after being bent, compared to the infrared reflective film 108 according to the comparative example. The reflection characteristic can be maintained, and according to the present invention, an optical film excellent in bending resistance can be provided.
Moreover, since the infrared reflective films 101-107 which concern on this invention are produced without requiring a baking process, a process is simple and it is excellent in bending resistance on the resin-made films as a transparent base material. Since the thin film is formed, it is suitable for roll transport in the production process, and it can be said that the productivity is excellent.

(Preparation of UV reflective film 201)
As a coating liquid containing cationic silicon oxide particles on a polycarbonate film (Teijin Chemicals S-5) having a thickness of 100 μm, the low refractive index layer coating liquid L6 prepared in Example 1 and anionic silicon oxide particles were used. The coating liquid L3 for low refractive index layer prepared in Example 1 as the coating liquid to be contained is spray-coated alternately by adjusting the coating amount so that the dry film thickness is 25 nm and the total thickness is 50 nm. A low refractive index layer was formed.

  As a coating liquid containing cationic titanium oxide particles on the formed low refractive index layer, a coating liquid H7 for high refractive index layer prepared in Example 1 and a coating liquid containing anionic titanium oxide particles, The coating liquid H3 for the high refractive index layer prepared in Example 1 was spray-coated alternately with the coating amount adjusted so that the dry film thickness was 25 nm and 50 nm in total, thereby forming the high refractive index layer of 50 nm. Formed.

By repeating these operations, a multi-layer coated product consisting of a total of 9 layers each consisting of 5 low refractive index layers and 4 high refractive index layers was produced.
It confirmed that there existed reflection in 200-400 nm UV area | region with the spectrophotometer (The use of an integrating sphere, Hitachi Ltd. make, U-4000 type) with respect to the produced UV reflection film 201. FIG.

(Preparation of visible light reflecting film 301)
On a 50 μm thick polyethylene terephthalate film (Toyobo A4300, double-sided easy-adhesion layer), as a coating solution containing cationic silicon oxide particles, a coating solution L6 for low refractive index layer prepared in Example 1 and anionic As a coating solution containing silicon oxide particles, the coating solution L1 for the low refractive index layer prepared in Example 1 is spray-coated alternately by adjusting the coating amount so that the dry film thickness is 20 nm and the total thickness is 40 nm. This was repeated twice to form an 80 nm low refractive index layer.

  As a coating liquid containing cationic titanium oxide particles on the formed low refractive index layer, a coating liquid H7 for high refractive index layer prepared in Example 1 and a coating liquid containing anionic titanium oxide particles, The coating liquid H1 for the high refractive index layer prepared in Example 1 was spray-coated alternately with the coating amount adjusted so that the dry film thickness was 15 nm and a total of 30 nm, respectively, and this was repeated twice to 60 nm. The high refractive index layer was formed.

By repeating these operations, a multi-layer coated product consisting of a total of 9 layers each consisting of 5 low refractive index layers and 4 high refractive index layers was produced.
Visible light reflection was confirmed visually with respect to the produced visible light reflection film 301.

2 Transparent substrate 10 1st film-forming part 11 Control part 12 Cationic silicon oxide particle supply part 13 Anionic silicon oxide particle supply part 14a, 14b Nozzle 15 Support part 20 2nd film-forming part 21 Control part 22 Cationic silicon oxide Particle supply unit 23 Anionic silicon oxide particle supply unit 24a, 24b Nozzle 25 Support unit 100 Manufacturing apparatus

Claims (10)

An optical interference film formed by laminating a high refractive index layer containing at least titanium oxide particles and a low refractive index layer containing at least silicon oxide particles on a transparent substrate, and In an optical film that selectively reflects,
The high refractive index layer includes a coating liquid containing a first water-soluble polymer and cationic titanium oxide particles, and a coating liquid containing a second water-soluble polymer and anionic titanium oxide particles. Formed by spraying,
The low refractive index layer includes a coating solution containing a third water-soluble polymer and cationic silicon oxide particles, and a coating solution containing a fourth water-soluble polymer and anionic silicon oxide particles. An optical film formed by being spray-coated on.   The optical film according to claim 1, wherein the anionic titanium oxide particles are titanium oxide particles coated with a silicon-containing hydrated oxide.   At least the first water-soluble polymer and the second water-soluble polymer are different from each other, or the third water-soluble polymer and the fourth water-soluble polymer are different from each other. The optical film according to claim 1 or 2.   At least the first water-soluble polymer and the second water-soluble polymer are the same type of water-soluble polymer and have different characteristics, or the third water-soluble polymer and the fourth water-soluble polymer are different from each other. The optical film according to any one of claims 1 to 3, wherein the water-soluble polymer is the same type of water-soluble polymer and has different characteristics.   At least the first water-soluble polymer and the second water-soluble polymer are polyvinyl alcohols having different saponification degrees and / or polymerization degrees, or the third water-soluble polymer and the second water-soluble polymer are the same. The optical film according to any one of claims 1 to 4, wherein the four water-soluble polymers are polyvinyl alcohols having different saponification degrees and / or polymerization degrees.   6. The optical film according to claim 1, wherein the optical film is used as an ultraviolet light reflecting film that reflects ultraviolet light.   The optical film according to claim 1, wherein the optical film is used as an infrared light reflecting film that reflects infrared light.   The optical film according to claim 1, wherein the optical film is used as a visible light reflecting film that reflects visible light.   6. The optical film according to claim 1, wherein the optical film is used as an antireflection film. An optical interference film formed by laminating a high refractive index layer containing at least titanium oxide particles and a low refractive index layer containing at least silicon oxide particles on a transparent substrate, and In the method for producing a selectively reflecting optical film,
The coating solution containing the first water-soluble polymer and the cationic titanium oxide particles and the coating solution containing the second water-soluble polymer and the anionic titanium oxide particles are alternately spray-coated, and the high Forming a refractive index layer;
The coating solution containing the third water-soluble polymer and the cationic silicon oxide particles and the coating solution containing the fourth water-soluble polymer and the anionic silicon oxide particles are alternately spray-coated, and the low And a step of forming a refractive index layer.

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