JP2016090977A - Method of manufacturing optical reflection film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical reflection film having good appearance.SOLUTION: A method of manufacturing an optical reflection film includes a step of coating a continuously running base material film 1 with a high refractive index layer-coating liquid and low refractive index layer-coating liquid 4 using a slide hopper coating apparatus to simultaneously form multiple layers in a range of 10-40 layers. The method is characterized in that; the high refractive index layer-coating liquid and low refractive index layer-coating liquid each has viscosity in a range of 5-200 mPA s at 40°C; the slide hopper coating apparatus has a slide surface tilted at an angle 8 of 2-25° with respect to a horizontal plane; a thickness t of each block of the slide hopper coating apparatus is 45-60 mm; and a sum of coating amount of high refractive index layer-coating liquid and low refractive index layer-coating liquid for each pair of adjacent high refractive index layer and low refractive index layer of all the layers formed by means of simultaneous multilayer coating other than a lower most layer is 11-16 g/m.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing an optical reflective film.

  Conventionally, multilayer laminated films such as an antireflection film, an infrared shielding film, and a color photosensitive material are manufactured by dry film formation or wet film formation. In terms of productivity, wet film formation in which application liquid is applied and dried is superior to dry film formation such as chemical vapor deposition (CVD) and physical vapor deposition (PVD).

  The slide hopper type coating apparatus is suitably used for the production of the multilayer laminated film as described above as a wet film forming apparatus capable of simultaneously applying a plurality of coating liquids. There is a need for a manufacturing method that reduces unevenness in the (conveying direction).

  For example, Patent Document 1 discloses a distance (hereinafter referred to as a slit portion) from a portion (hereinafter referred to as a chamber) that spreads the coating liquid in a slide hopper type coating device to the coating width in the width direction of the base film. A manufacturing method is disclosed in which the uniformity of the quality of the coating film is improved by setting the length and notation to 40 mm or more. According to this manufacturing method, it is possible to provide a small and light slide hopper type coating apparatus with high uniformity of coating film quality.

JP 2009-28604 A

  However, since the coating liquid used for the production of the optical reflection film uses both a low-viscosity liquid and a high-viscosity liquid, the flow rate of the high-viscosity coating liquid is small, so the dynamic pressure is low and sharp streaks appear on the coating surface. In some cases, an irregular failure (hereinafter also referred to as a streak failure) and a broad coating unevenness (hereinafter also referred to as a vertical unevenness failure) in the longitudinal direction of the film, that is, the vertical direction, appear. In this regard, there is still room for improvement in the above prior art.

  Then, an object of this invention is to provide the manufacturing method of an optical reflection film which can suppress a stripe failure and a vertical nonuniformity failure.

The present inventors have conducted intensive studies in view of the above problems. As a result, it has surprisingly been found that the above-mentioned problems can be solved by the following present invention. That is,
Optical including a step of simultaneously applying 10 to 40 layers of a coating solution for a high refractive index layer and a coating solution for a low refractive index layer on a continuously running substrate film using a slide hopper coating device A method of manufacturing a reflective film,
The viscosity at 40 ° C. of the high refractive index layer coating liquid and the low refractive index layer coating liquid is 5 to 200 mPa · s,
The angle of the slide surface of the slide hopper type coating device with respect to the horizontal plane is 2 to 25 °,
The thickness per block of the slide hopper type coating device is 45 to 60 mm,
The total coating amount of the coating solution for the high refractive index layer and the coating solution for the low refractive index layer of the adjacent high refractive index layer and the low refractive index layer excluding the lowermost layer formed by the simultaneous multilayer coating is 11 to 11. a 16g / ^{m 2,} a manufacturing method of an optical reflective film.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the optical reflection film which can reduce the stripe fault of a coating surface and a vertical nonuniformity fault is provided.

It is the schematic which shows an example of a slide hopper type coating device. It is a schematic diagram of the milder of an example of a dispersing device.

According to one form of this invention, the manufacturing method of the following optical reflective films is provided. In the production method of the present invention, a coating solution for a high refractive index layer and a coating solution for a low refractive index layer are simultaneously applied on a continuously running base film using a slide hopper coating device. Including a step of applying multiple layers. In such a manufacturing method, the viscosity of the coating solution for the high refractive index layer and the coating solution for the low refractive index layer at 40 ° C. is 5 to 200 mPa · s, and the angle of the slide surface of the slide hopper type coating device with respect to the horizontal plane is It is 2 to 25 °, and the thickness per block of the slide hopper type coating device is 45 to 60 mm. Furthermore, in such a manufacturing method, the coating liquid for the high refractive index layer and the coating liquid for the low refractive index layer of the adjacent high refractive index layer and the low refractive index layer, excluding the lowermost layer, formed by the simultaneous multilayer coating. The total coating amount is 11 to 16 g / m ² . In the present specification, for example, 5 to 200 mPa · s indicates a range of 5 mPa · s to 200 mPa · s.

[Optical reflection film]
The optical reflection film manufactured by the above manufacturing method has a configuration in which a laminate including a high refractive index layer and a low refractive index layer is disposed on at least a substrate. By adopting such a configuration and appropriately controlling the optical film thickness (film thickness × refractive index) of the high refractive index layer and the low refractive index layer, light having a specific wavelength can be reflected.

  Accordingly, the optical reflection film becomes, for example, an ultraviolet shielding film when reflecting a light beam (ultraviolet light) having a wavelength of 200 to 400 nm, and a visible light colored film when reflecting a light beam (visible light) having a wavelength of 400 to 700 nm. In the case of reflecting light rays (infrared rays) having a wavelength of 700 to 1200 nm, it can be an infrared shielding film.

  In addition, by appropriately designing the optical film thickness and the like of the laminate, the wavelength and reflectance of the reflected light beam can be controlled to obtain a metallic glossy film. Among these, the light ray that can be shielded by the optical reflection film is preferably a light ray having a wavelength of 200 nm to 1000 μm in the ultraviolet to infrared region, more preferably a light ray having a wavelength of 250 to 2500 nm, and a wavelength of 700 to 1200 nm. The light in the near infrared region is more preferable.

  In the following description, a method for producing an infrared shielding film will be described as a representative example of the optical reflecting film, but the present invention is not limited thereto.

[Infrared shielding film]
The configuration of the infrared shielding film according to an embodiment of the present invention is not particularly limited, but preferably includes a base film and at least one unit composed of a high refractive index layer and a low refractive index layer. More preferably, it has a form of an alternating laminate in which high refractive index layers and low refractive index layers are alternately laminated. In the present specification, a refractive index layer having a higher refractive index than the other is referred to as a high refractive index layer, and a refractive index layer having a lower refractive index than the other is referred to as a low refractive index layer.

  In this embodiment, the infrared shielding film preferably includes at least one unit composed of two layers having different refractive indexes, that is, a high refractive index layer and a low refractive index layer. For example, when each of the high refractive index layer and the low refractive index layer contains metal oxide particles, the metal oxide particles contained in the low refractive index layer (hereinafter referred to as “first metal oxide particles”), Metal oxide particles (hereinafter referred to as “second metal oxide particles”) contained in the high refractive index layer are mixed at the interface between the two layers, and the first metal oxide particles and the second metal are mixed. A layer containing oxide particles may be formed. In that case, it is regarded as a low refractive index layer or a high refractive index layer depending on the abundance ratio of the first metal oxide particles and the second metal oxide particles. Specifically, the low refractive index layer means that the first metal oxide particles are 50 to 100% by mass with respect to the total mass of the first metal oxide particles and the second metal oxide particles. Means the layers involved. The high refractive index layer means that the second metal oxide particles are more than 50% by mass and less than 100% by mass with respect to the total mass of the first metal oxide particles and the second metal oxide particles. Means the layers involved. The type and amount of metal oxide particles contained in the refractive index layer can be analyzed by energy dispersive X-ray spectroscopy (EDX).

The metal oxide particles used in the present invention is not particularly limited, titanium oxide _(TiO 2), zinc oxide (ZnO), zirconium oxide _(ZrO 2), niobium oxide _{(Nb 2 O} 5), aluminum oxide (Al ₂ O ₃ ), silicon oxide (SiO ₂ ), calcium fluoride (CaF ₂ ), magnesium fluoride (MgF ₂ ), indium tin oxide (ITO), antimony tin oxide (ATO), and the like. Among these, titanium oxide (TiO ₂ ) is used as the second metal oxide particles contained in the coating solution for the high refractive index layer, and silicon oxide is used as the first metal oxide particles contained in the coating solution for the low refractive index layer. It is preferable to use (SiO ₂ ), respectively.

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

As a method of coating titanium oxide particles with a silicon-containing hydrated oxide, it can be produced by a conventionally known method. For example, JP-A-10-158015 (Si / Al hydration to rutile titanium oxide) Oxide treatment; a method of producing a titanium oxide sol in which a hydrous oxide of silicon and / or aluminum is deposited on the surface of titanium oxide after peptization in the alkaline region of the titanate cake), JP 2000-204301 A (A sol in which a rutile titanium oxide is coated with a complex oxide of Si and Zr and / or Al. Hydrothermal treatment), JP 2007-246351 (Oxidation obtained by peptizing hydrous titanium oxide) titanium to hydrosol, wherein ^R _{1 n SiX 4-n} (wherein ^{R 1} is C1-C8 alkyl group as a stabilizer, glycidyloxy substituted C1-C8 A compound having a complexing action with respect to an organoalkoxysilane or titanium oxide of an alkyl group or a C2-C8 alkenyl group, X is an alkoxy group, and n is 1 or 2. Sodium silicate or silica sol in an alkali region is added. The method described in, for example, a method for producing a titanium oxide hydrosol coated with a hydrous oxide of silicon by adding, pH adjusting, and aging to the above solution can be referred to.

  In general, in an infrared shielding film, it is preferable to design a large difference in refractive index between a low refractive index layer and a high refractive index layer from the viewpoint that the infrared reflectance can be increased with a small number of layers. In the infrared shielding film according to this embodiment, in at least one of the units composed of the low refractive index layer and the high refractive index layer, the refractive index difference between the adjacent low refractive index layer and the high refractive index layer is 0.1. Preferably, it is 0.3 or more, more preferably 0.35 or more, and particularly preferably 0.4 or more. When the infrared shielding film has a plurality of units of a high refractive index layer and a low refractive index layer, the refractive index difference between the high refractive index layer and the low refractive index layer in all the units is within the preferred range. Is preferred. However, regarding the outermost layer and the lowermost layer, a configuration outside the above preferred range may be used. Moreover, in the infrared shielding film of this embodiment, the preferable refractive index of a low refractive index layer is 1.10-1.60, More preferably, it is 1.30-1.50. Moreover, the preferable refractive index of a high refractive index layer is 1.80-2.50, More preferably, it is 1.90-2.20.

  In the present invention, the refractive indexes of the high refractive index layer and the low refractive index layer can be determined according to the following method.

  A sample in which each refractive index layer for measuring the refractive index is coated as a single layer on a base film is prepared, and the sample is cut into 10 cm × 10 cm, and then the refractive index is obtained according to the following method. Using a U-4000 type (manufactured by Hitachi, Ltd.) as a spectrophotometer, after roughening the back side on the measurement side of each sample, light absorption treatment is performed with a black spray to reduce the light on the back side. The reflection is prevented, the reflectance in the visible light region (400 nm to 700 nm) is measured at 25 points under the condition of regular reflection at 5 degrees, the average value is obtained, and the average refractive index is obtained from the measurement result.

  The reflectance in the specific wavelength region is determined by the difference in refractive index between two adjacent layers and the number of stacked layers. The refractive index difference and the required number of layers can be calculated using commercially available optical design software. For example, in order to obtain an infrared reflectance of 90% or more, if the difference in refractive index is less than 0.1, it is necessary to laminate 200 layers or more, which not only decreases productivity but also scattering at the interface of the layers. Becomes larger, the transparency is lowered, and it becomes very difficult to manufacture without failure. From the standpoint of improving reflectivity and reducing the number of layers, there is no upper limit to the difference in refractive index, but practically about 1.4 is the limit.

  The number of infrared shielding films according to this embodiment is 10 to 40 layers, preferably 10 to 34 layers, and more preferably 10 to 26 layers. Moreover, the infrared shielding film of this form may be a laminated film in which both the outermost layer and the lowermost layer of the laminated film are a high refractive index layer or a low refractive index layer. The infrared shielding film according to this embodiment preferably has a layer structure in which the lowermost layer adjacent to the base film is a low refractive index layer and the outermost layer is also a low refractive index layer.

  The total thickness of the infrared shielding film according to this embodiment is preferably 12 μm to 315 μm, more preferably 15 μm to 200 μm, and still more preferably 20 μm to 150 μm. Moreover, it is preferable that the film thickness after drying per layer of the low-refractive-index layer except a lowermost layer is 30-500 nm, and it is more preferable that it is 30-300 nm. On the other hand, the film thickness after drying per layer of the high refractive index layer excluding the lowermost layer is preferably 30 to 500 nm, and more preferably 30 to 300 nm. The film thickness after drying of the lowermost layer is preferably 300 to 1500 nm, more preferably 400 to 1200 nm, regardless of whether the lowermost layer is a low-refractive index layer or a high-refractive index layer.

  Furthermore, as an optical characteristic of the infrared shielding film according to the present embodiment, the transmittance in the visible light region represented by JIS R3106: 1998 is preferably 50% or more, more preferably 75% or more, and further preferably 85% or more. In addition, it is preferable that the region having a wavelength of 900 nm to 1400 nm has a region with a reflectance exceeding 50%.

  The infrared shielding film according to this embodiment is a conductive layer, an antistatic layer, a gas barrier layer, an easy layer, for the purpose of adding further functions under the base film or on the outermost surface layer opposite to the base film. Adhesive layer (adhesive layer), antifouling layer, deodorant layer, droplet layer, slippery layer, hard coat layer, wear-resistant layer, antireflection layer, electromagnetic wave shielding layer, ultraviolet absorption layer, infrared absorption layer, printing Layer, fluorescent light emitting layer, hologram layer, release layer, adhesive layer, adhesive layer, infrared cut layer (metal layer, liquid crystal layer) other than the high refractive index layer and low refractive index layer of the present invention, colored layer (visible light absorbing layer) ), And may have one or more functional layers such as an interlayer film used for laminated glass.

[Infrared shielding film manufacturing method]
The coating solution used in the present invention is applied by simultaneous multilayer coating using a slide hopper type coating device. In that case, a high refractive index layer and a low refractive index layer are formed by laminating a coating solution for high refractive index and a coating solution for low refractive index on the slide surface and coating the substrate film. As a preferred embodiment, a simultaneous multilayer coating process is performed through the following adjustment process, circulation process, and supply process.

<Preparation process>
In a preparation process, the coating liquid which forms the high refractive index layer and low refractive index layer of an infrared shielding film is prepared, respectively. The preparation process includes a preparation kettle, a liquid feeding device, and a filtration device.

  The preparation kettle is a container for preparing a polymer-containing coating solution. The method for preparing the coating solution is not particularly limited, and is, for example, a method in which metal oxide particles, a water-soluble polymer, and other additives that are added as necessary are added to a solvent and mixed by stirring. At this time, the order of addition of the respective components is not particularly limited, and the respective components may be sequentially added and mixed while stirring, or may be added and mixed at one time while stirring. The method for preparing these coating solutions is appropriately determined for each coating solution. The preparation kettle is connected to the storage kettle in order to supply the coating liquid to the kettle included in the circulation process.

  The liquid feeding device is provided in a path through which the coating liquid flows out from the preparation kettle. The liquid feeding device is, for example, a pump and can control the outflow of the prepared coating liquid and the stoppage of the outflow. The liquid delivery device can appropriately set the flow rate and speed of the coating liquid when the coating liquid is allowed to flow out.

  The filtration device is provided in a path through which the coating liquid flows out from the preparation kettle. The filtering device removes foreign matters mixed in the coating liquid, and foreign matters caused by bubbles or aggregation generated in the coating liquid. The coating liquid from which the foreign matter has been removed is sent to a circulation process.

(Coating solution)
In the present invention, the coating liquid for the low refractive index layer and the coating liquid for the high refractive index layer are water-soluble polymers such as polyvinyl alcohols because the coating film can be set after coating and mixing between layers can be suppressed. And an aqueous coating solution containing water or an aqueous solvent containing water and a water-soluble organic solvent is preferably used.

  The viscosity at 40 ° C. of the coating solution for high refractive index layer and the coating solution for low refractive index layer is 5 to 200 mPa · s, preferably 20 to 180 mPa · s. When the viscosity is less than 5 mPa · s, the dynamic pressure of the slide surface flow is insufficient, resulting in streak failure. On the other hand, when it exceeds 200 mPa · s, deformation of the block occurs even if the thickness per block is 45 to 60 mm, which is not preferable. The viscosity is a value measured with a Brookfield viscometer.

  The concentration of the solid content of the coating solution is preferably 0.1 to 10% by mass, and more preferably 0.1 to 5% by mass. This is because in this range, the solid content is low and the uniformity of the coating solution is high, so that the film thickness uniformity is considered to be further improved.

  The concentration of the water-soluble polymer in the coating solution for the low refractive index layer is preferably 0.1 to 10% by mass. Moreover, it is preferable that the density | concentration of the 1st metal oxide particle in the coating liquid for low refractive index layers is 1-60 mass%.

  The concentration of the water-soluble polymer in the coating solution for the high refractive index layer is preferably 0.5 to 10% by mass. Moreover, it is preferable that the density | concentration of the 2nd metal oxide particle in the coating liquid for high refractive index layers is 1-60 mass%.

  In addition, it is preferable to use what was prepared in the state of the dispersion liquid separately before preparing a coating liquid as the 2nd metal oxide particle used for the coating liquid for high refractive index layers. That is, it is preferable to form the high refractive index layer using an aqueous high refractive index coating solution prepared by adding and dispersing rutile type titanium oxide having a volume average particle size of 100 nm or less. Furthermore, it is more preferable to form the high refractive index layer using an aqueous coating solution for high refractive index layer prepared by adding and dispersing titanium oxide particles coated with a silicon-containing hydrated oxide. In the case of using a dispersion liquid, the dispersion liquid may be appropriately added so as to have an arbitrary concentration in each layer.

(solvent)
The solvent for preparing the coating solution for the high refractive index layer and the coating solution for the low refractive index layer is not particularly limited, but water, an organic solvent, or a mixed solvent thereof is preferable.

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

  From the viewpoint of environment and simplicity of operation, the solvent for the coating solution is particularly preferably water or a mixed solvent of water and methanol, ethanol, or ethyl acetate.

(Water-soluble polymer)
Examples of the water-soluble polymer used in the present invention include polyvinyl alcohols, polyvinyl pyrrolidones, polyvinyl butyral, polyacrylic acid, acrylic acid-acrylonitrile copolymer, potassium acrylate-acrylonitrile copolymer, vinyl acetate. -Acrylic resin such as acrylic ester copolymer or acrylic acid-acrylic ester copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic ester copolymer Styrene acrylic acid 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-hydroxy Ethyl 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 -Synthetic water such as maleic acid copolymers, vinyl acetate-maleic acid ester copolymers, vinyl acetate-crotonic acid copolymers, vinyl acetate copolymers such as vinyl acetate-acrylic acid copolymers and their salts Natural water-soluble polymers such as gelatin and thickening polysaccharides. Among these, particularly preferred examples include polyvinyl alcohols, polyvinylpyrrolidones, and copolymers containing them, polyvinyl butyral, gelatin, thickening polysaccharides from the viewpoint of handling during production and film flexibility. (Especially celluloses). These water-soluble polymers may be used alone or in combination of two or more.

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

  Polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate preferably has an average degree of polymerization of 1,000 or more, particularly preferably an average degree of polymerization of 1,500 to 5,000, and 2,000 to 5,000 is more preferably used. This is because when the polymerization degree of polyvinyl alcohol is 1,000 or more, there is no cracking of the coating film, and when it is 5,000 or less, the coating solution is stable. In addition, that the coating solution is stable means that the coating solution is stabilized over time. The same applies hereinafter.

  The saponification degree is preferably 70 to 100%, more preferably 80 to 99.5% in view of solubility in water.

  In the present invention, in addition to the polyvinyl alcohol having an average polymerization degree of 1,000 or more, a low polymerization degree highly saponified polyvinyl alcohol having a polymerization degree of 100 to 500 and a saponification degree of 95 mol% or more is used. It is preferable that at least one of the low refractive index layers includes. By containing such a low polymerization degree highly saponified polyvinyl alcohol, the stability of the coating solution is improved.

  Furthermore, as long as the effect of the present invention is not impaired, at least one of the high refractive index layer and the low refractive index layer is modified in part other than normal polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate. Polyvinyl alcohol may be included. Examples of such modified polyvinyl alcohol include cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, nonion-modified polyvinyl alcohol, and vinyl alcohol polymers.

  Examples of the cation-modified polyvinyl alcohol include primary to tertiary amino groups and quaternary ammonium groups, as described in JP-A No. 61-10383, in the main chain or side chain of the polyvinyl alcohol. It 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 preferably 0.1 to 10 mol%, more preferably 0.2 to 5 mol% with respect to vinyl acetate.

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

  Nonionic modified polyvinyl alcohol includes, for example, a polyvinyl alcohol derivative in which a polyalkylene oxide group as described in JP-A-7-9758 is added to a part of vinyl alcohol, and JP-A-8-25795. Block copolymer of vinyl compound having a hydrophobic group and vinyl alcohol, silanol-modified polyvinyl alcohol having silanol group, reactive group modification having reactive group such as acetoacetyl group, carbonyl group, carboxyl group Polyvinyl alcohol etc. are mentioned.

  These polyvinyl alcohols may be used alone or in combination of two or more such as the degree of polymerization and the type of modification. As the polyvinyl alcohols, commercially available products or synthetic products may be used. Examples of commercially available products include, for example, PVA-102, PVA-103, PVA-105, PVA-110, PVA-117, PVA-120, PVA-124, PVA-135, PVA-203, PVA-205, PVA -210, PVA-217, PVA-220, PVA-224, PVA-235, PVA-617, etc. Poval (manufactured by Kuraray Co., Ltd.), EXEVAL (registered trademark, manufactured by Kuraray Co., Ltd.), Nichigo G polymer (registered trademark, Nippon Synthetic Chemical Industry Co., Ltd.).

(Additive)
Various additives can be added to the coating solution for the low refractive index layer and the coating solution for the high refractive index layer according to the present invention as necessary. Hereinafter, the additive will be described.

(Curing agent)
In the low refractive index layer and the high refractive index layer according to the present invention, it is preferable to add a curing agent. Examples of the curing agent include a curing agent that causes a curing reaction with polyvinyl alcohol suitable as the water-soluble polymer. Specifically, boric acid and its salt are preferable. In addition to boric acid and its salts, known ones can be used, generally a compound having a group capable of reacting with polyvinyl alcohol or a compound that promotes the reaction between different groups possessed by polyvinyl alcohol, It is appropriately selected and used. Specific examples of curing agents other than boric acid and salts thereof include, for example, epoxy-based 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-based curing agents (formaldehyde, glycoxal, etc.), active halogen-based curing agents (2,4-dichloro-4- Hydroxy-1,3,5-s-triazine, etc.), active vinyl compounds (1,3,5-trisacryloyl-hexahydro-s-triazine, bisvinylsulfonylmethyl ether, etc.), aluminum alum and the like.

  Boric acid and its salts refer to oxygen acids and their salts having a boron atom as a central atom, specifically, orthoboric acid, diboric acid, metaboric acid, tetraboric acid, pentaboric acid and octabored acid. Examples include acids and their salts.

  Boric acid having a boron atom and a salt thereof as a curing agent may be used alone or in a mixture of two or more. Particularly preferred is a mixed aqueous solution of boric acid and borax.

  The aqueous solutions of boric acid and borax can be added only in relatively dilute aqueous solutions, respectively, but by mixing them both can be made into a concentrated aqueous solution and the coating solution can be concentrated. Further, there is an advantage that the pH of the aqueous solution to be added can be controlled relatively freely.

  In the present invention, it is preferable to use boric acid and a salt thereof and / or borax from the viewpoint of further suppressing interlayer mixing. When boric acid and salts thereof and / or borax are used, metal oxide particles and OH groups of polyvinyl alcohols which are water-soluble binder resins form a hydrogen bond network, resulting in a high refractive index layer. It is considered that the interlayer mixing between the low refractive index layer and the low refractive index layer is suppressed, and preferable near-infrared shielding characteristics are achieved. Especially when using a set coating process in which a multi-layered multilayer of a high refractive index layer and a low refractive index layer is applied with a coater, the film surface temperature of the coating film is once cooled to about 15 ° C., and then the film surface is dried. In this case, the effect can be expressed more preferably.

  The total amount of the curing agent used is preferably 1 to 600 mg per 1 g of polyvinyl alcohol, and more preferably 100 to 600 mg per 1 g of polyvinyl alcohol.

(Other additives)
Various additives that can be added to the coating solution for the high refractive index layer and the coating solution for the low refractive index layer according to the present invention are listed below. For example, ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988, and JP-A-62-261476, JP-A-57-74192, and JP-A-57-87989. , JP-A-60-72785, JP-A-61-14659, JP-A-1-95091, JP-A-3-13376, etc. Nonionic surfactants, JP-A-59-42993, JP-A-59-52689, JP-A-62-280069, JP-A-61-228771, and JP-A-4-219266 Whitening agent, sulfuric acid, phosphoric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate, sodium acetate, etc. pH adjusters, antifoaming agents, lubricants such as diethylene glycol, preservatives, antifungal agents, antistatic agents, matting agents, heat stabilizers, antioxidants, flame retardants, crystal nucleating agents, inorganic particles, organic particles, reduction Various known additives such as a sticky agent, a lubricant, an infrared absorber, a dye, and a pigment can be used.

<Circulation process>
In the circulation step (coating liquid circulation system), the prepared coating liquid is circulated while maintaining proper physical properties. The circulation process is performed using a storage pot, a liquid feeding device, a dispersion device, a defoaming device, a filtration device, and a circulation path.

  The storage pot stores the coating liquid so that the coating liquid can be continuously supplied. The storage tank is preferably provided with a stirring device for circulating the coating liquid even inside the storage tank. Thereby, the physical property of the coating liquid in a storage pot can be made uniform. A circulation path is connected to the storage tank for allowing the coating liquid to flow out of the storage tank and returning the discharged coating liquid to the storage tank again. In addition, a supply path for sending the coating liquid to the supply process and the application process is also connected to the storage hook.

  The liquid feeding device is provided on the circulation path. The liquid feeding device is, for example, a pump, and can control the outflow of the coating liquid stored in the storage hook and the stoppage of the outflow. The liquid delivery device can appropriately set the flow rate and speed of the coating liquid when the coating liquid is allowed to flow out.

  The dispersing device is provided on the circulation path. The dispersion device performs dispersion treatment or shear treatment on the coating solution. As a result, in the coating solution, the bonds (van der Waals bonds, etc.) between the molecules of the polymer and the terminal groups in the molecule are broken, so that the entanglement between the molecules is eliminated, and as a result, the viscosity is reduced.

  The configuration of the dispersing device is not particularly limited as long as the coating liquid can be dispersed and sheared, and may be a commercially available milder, a pressure type homogenizer, a high-speed rotational shearing type homogenizer, or the like. In the case of a milder, for example, the dispersing device causes the coating liquid to flow between the fixed teeth and the movable teeth, and the coating liquid is dispersed or sheared by a shearing force generated by a velocity gradient between the fixed teeth and the movable teeth.

  The dispersion device performs dispersion treatment or shear treatment on the coating solution. As a result, in the coating solution, the bonds (van der Waals bonds, etc.) between the molecules of the polymer and the terminal groups in the molecule are broken, so that the entanglement between the molecules is eliminated, and as a result, the viscosity is reduced. The configuration of the dispersing device is not particularly limited as long as the coating liquid can be dispersed and sheared, and may be a commercially available milder, a pressure type homogenizer, a high-speed rotational shearing type homogenizer, or the like. In the case of a milder, for example, the dispersing device causes the coating liquid to flow between the fixed teeth and the movable teeth, and the coating liquid is dispersed or sheared by a shearing force generated by a velocity gradient between the fixed teeth and the movable teeth.

  FIG. 2 is a schematic diagram of a milder that is an example of a dispersing device that can be used in the circulation process. The milder in FIG. 2 has a stator tooth 31 that is a fixed tooth and a rotor tooth 32 that is a rotating tooth. The shear target liquid 34 moving in the gap (shear gap) La between the stator teeth 31 and the rotor teeth 32 has a velocity gradient (shear velocity) in the radial direction of the rotor teeth 32. Due to the velocity gradient, an internal frictional force (shearing force) is generated between the stator teeth 31 and the rotor teeth 32. Since the introduction of the shear target liquid 35 into the shear gap La is performed in the radial direction from the slit gap of the rotor teeth 32, the shear target liquid 34 flowing into the shear gap La and the introduced shear target liquid 35 are continuous. Will have repeated collisions. That is, according to the milder in FIG. 2, shearing and mixing are continuously performed on the liquid to be sheared.

  As a rotational speed of the milder which is a disperser which can be used for a circulation process, 1000-9000 rpm is preferable, More preferably, it is 2000-8000 rpm. Moreover, in order to supply a coating liquid to a dispersion process, 3-10 L / min is preferable and, as for the flow volume of the coating liquid at the time of sending a circulation path, More preferably, it is 5-10 L / min. When the rotational speed of the milder and the flow rate of the coating liquid are within the ranges, there is an effect of preventing the aggregation of the coating liquid.

  The minimum gap between the stator teeth and the rotor teeth in the shear gap is preferably 0.05 to 0.5 mm, and more preferably 0.1 to 0.4 mm. The shear rate can be adjusted by appropriately setting the minimum gap between the stator teeth and the rotor teeth in the shear gap and the rotational speed of the rotor teeth.

  As such a milder, for example, Ebara Milder (manufactured by Ebara Manufacturing Co., Ltd.), Milder (manufactured by Taihei Kiko Co., Ltd. MDN306) or the like can be used.

  The defoaming device removes bubbles contained in the coating liquid and dissolved air dissolved in the coating liquid. As a principle of defoaming, for example, a method of separating bubbles and liquid by centrifugal force and discharging the bubbles by evacuation or a method using ultrasonic waves can be considered. However, as long as defoaming can be performed, the defoaming device may be a device using any other principle.

  The filtering device removes foreign matters mixed in the coating liquid, and foreign matters caused by bubbles or aggregation generated in the coating liquid. The coating liquid from which the foreign matter has been removed returns to the storage tank through the circulation path.

  As described above, in the circulation step, the coating liquid flows out from the storage kettle to the circulation path, is subjected to treatment by the dispersing device, the defoaming device, and the filtration device, and then returns to the storage kettle. The coating liquid returned to the storage pot moves while being stirred in the storage pot, and then flows out to the circulation path again, and the above processing is repeated.

  The processing strength of the dispersion device, the defoaming device and the filtration device in the circulation process is such that the physical properties of the coating liquid are maintained within an appropriate range depending on the application conditions of the infrared shielding film and the properties of the coating liquid used. It can set suitably as follows.

  In the circulation step, while the prepared coating liquid is circulated, a dispersion treatment, a defoaming treatment, a filtration treatment, etc. are continuously performed at an appropriate strength, so that the physical properties such as the viscosity of the coating solution are suitable for coating. Can be kept inside.

  In the circulation process, the number of times the coating liquid is circulated is not predetermined, and a predetermined flow rate of the coating liquid is supplied from the storage tank to the circulation path according to the setting of the liquid feeding device and the like. It is sent sequentially and circulates. Since the circulated coating liquid is returned to the storage kettle and stirred, the physical properties of the entire coating liquid contained in the storage kettle can always be kept in a state suitable for coating.

  A part of the coating liquid stored in the storage tank is sent to the supply process through a supply path connected to the storage tank.

  Note that the order of the dispersing device, the defoaming device, and the filtering device on the circulation path can be appropriately changed. In addition, one device that integrates the functions of a plurality of the above devices may be provided for the circulation process. For example, a dispersion defoaming device in which the functions of the dispersion device and the defoaming device are integrated may be provided in the circulation process. Further, in the circulation step, a device other than the above may be provided, or any of the above devices may not be provided.

<Supply process>
In the supplying process, the prepared and circulated coating liquid is supplied to the simultaneous multilayer coating process. A supply process is implemented using a liquid feeding apparatus, a flow meter, a defoaming apparatus, a filtration apparatus, and a supply path. The supply path is a path for supplying the coating liquid from the storage tank in the circulation process to the coating process. The liquid feeding device, the flow meter, the defoaming device, and the filtration device are provided in the supply path.

  The liquid feeding device sends the coating liquid discharged from the storage tank in the circulation process to each device provided in the supply path. The liquid feeding device is, for example, a pump and can control the outflow of the prepared coating liquid and the stoppage of the outflow. The liquid delivery device can appropriately set the flow rate and speed of the coating liquid when the coating liquid is allowed to flow out.

  The flow meter is a device that measures the flow rate of the coating liquid passing through the supply path. The flow rate of the liquid feeding device may be appropriately controlled according to the flow rate of the coating liquid measured by the flow meter. As the flow meter, for example, a Coriolis type, electromagnetic type, flap type, hot wire type, Karman vortex type, or negative pressure sensing type flow meter is used. A pressure gauge that measures the pressure of the coating liquid in the supply path may be provided in addition to the flow meter or instead of the flow meter.

  The filtering device removes foreign matters mixed in the coating liquid, and foreign matters caused by bubbles or aggregation generated in the coating liquid. The coating liquid from which the foreign matter has been removed is sent to the coating process through the supply path.

  Note that the order of the flow meter, the defoaming device, and the filtering device on the supply path can be changed as appropriate. Moreover, one apparatus which integrated the function of the said several apparatus may be provided for a supply process. Further, in the supply process, a device other than the above may be provided, or any of the above devices may not be provided. However, in order to avoid excessive dispersion of the coating liquid, it is preferable not to perform a dispersion process in the supply process.

<Simultaneous multilayer coating process>
Through the above supply step, the coating solution for the high refractive index layer and the coating solution for the low refractive index layer are supplied to the simultaneous multilayer coating step. In the simultaneous multi-layer coating process, a high refractive index layer and a low refractive index layer are formed by laminating a coating solution for high refractive index and a coating solution for low refractive index on the slide surface and coating the substrate film. . For simultaneous multilayer coating, it is preferable to use a slide hopper type coating apparatus.

  FIG. 1 is a schematic view showing an example of a slide hopper type coating apparatus used in the present invention.

  The base film 1 that is continuously transported is held by the back roll 2 that rotates in the same direction in accordance with the transport speed of the base film 1 that is at the position facing the coater die 3, and the wetted part 6 Is applied. The coater die 3 is composed of a plurality of blocks 11 (in FIG. 1, a four-layer simultaneous application mode is shown), on which the coating liquid 4 flows down. Further, the coater die 3 is fixed to a coater die holding base (not shown) at an angle 8 with respect to a horizontal plane of a fixed slide surface. A decompression chamber 5 is provided at the lower part between the back roll 2 and the coater die 3. In order to stabilize the bead formed in the liquid contact part 6, the decompression chamber 5 is evacuated from the decompression part 10 in order to depressurize the bead, specifically, the lower part of the bead. Is a negative pressure. 1 in FIG. 1 is an angle formed by the center of the back roll 2 and the liquid contact portion 6, and 9 in FIG. 1 is an angle formed by the running surface of the base film 1 and the slide surface.

In the present invention, the angle 8 with respect to the horizontal plane of the slide surface shown in FIG. 1 is 2 to 25 °, and the thickness per block is 45 to 60 mm. Furthermore, the sum of the coating amount on the coating surface of the coating solution for the high refractive index layer and the coating solution for the low refractive index layer, excluding the lowermost layer, is 11 to 16 g / m ² . Thereby, a stripe failure and a vertical unevenness failure do not occur on the coated surface, and an infrared shielding film having a good appearance can be obtained. In the present invention, the thickness per block is the distance indicated by t in FIG.

  In the manufacturing method of this invention, the angle with respect to the horizontal surface of the slide surface of a slide hopper type coating device is 2-25 degrees. If the angle is less than 2 °, even if the thickness per block and the sum of the coating amount are within the predetermined range, the flow velocity on the slide surface becomes slow, and the dynamic pressure on the slide surface decreases, causing streak failure. Cause. On the other hand, when the angle exceeds 25 °, ripples occur on the slide surface, which is not preferable. The angle is preferably 5 to 20 °.

  Furthermore, in the manufacturing method of this invention, the thickness per block of a slide hopper type coating device is 45-60 mm. In the slide hopper type coating apparatus, the flow of the coating solution supplied to the center is spread in the width direction of the base film at a portion called a chamber, and flows out from the portion called a slit to the slide surface. At this time, it is necessary to make the fluid resistance of the slit portion sufficiently large, and by making the length of the slit long, the flow of the coating liquid is made uniform. In the production method of the present invention, a high-viscosity liquid and a low-viscosity liquid are used in combination. The portion where the viscous liquid flows is largely different from the portion where the low-viscosity liquid flows. Therefore, when the angle of the slide surface with respect to the horizontal plane and the sum of the coating amounts are within the above ranges, the thickness per block needs to be 45 mm or more for the uniformity of the coating film. In addition, when the thickness per block is more than 60 mm, there is a possibility that ripples occur on the slide surface. The thickness per block is more preferably 45 to 55 mm. In addition, when performing simultaneous multilayer coating, the slide hopper type coating apparatus has a plurality of blocks, but the thickness of the plurality of blocks may be the same or different. However, the thickness of the plurality of blocks is preferably the same from the viewpoint of obtaining the effect of the present invention more efficiently and the viewpoint of simplifying the apparatus.

Moreover, in this invention, the coating amount sum in the application surface of the coating liquid for high refractive index layers and the coating liquid for low refractive index layers of the adjacent high refractive index layer and low refractive index layer except the lowest layer is 11-11. 16 g / m ² . If the total coating amount is less than 11 g / m ² , streak failure and vertical unevenness failure may occur. On the other hand, even if it exceeds 16 g / m ² , further effects of suppressing streak failure and vertical unevenness failure cannot be obtained. According to a preferred embodiment, the total coating amount is 12 to 15 g / m ² , and according to a more preferred embodiment, 12 to 14 g / m ² . Here, “the total coating amount” means the coating amount of the coating solution for the high refractive index layer of the high refractive index layer excluding the lowermost layer and the lowermost layer adjacent to the high refractive index layer. It is the sum of the coating amount on the coating film of the coating solution for the low refractive index layer of the low refractive index layer. The lowest layer refers to the layer closest to the base film. The infrared shielding film is a laminate in which high refractive index layers and low refractive index layers are alternately laminated. The above-mentioned range should just satisfy | fill the said coating amount sum in the combination of the arbitrary adjacent high refractive index layer and low refractive index layer of two or more layers from the base film side among this laminated body. However, the higher the number of combinations of the high refractive index layer and the low refractive index layer that satisfy the above-mentioned range of the total coating amount, the better.

  In addition, said mechanism is based on estimation and this invention is not restrict | limited to the said mechanism at all.

  In a preferred embodiment of the present invention, the coating amount ratio of the coating liquid for the high refractive index layer and the coating liquid for the low refractive index layer (high refractive index) of the adjacent high refractive index layer and low refractive index layer, excluding the lowermost layer. (Layer / low refractive index layer) is set to 0.7 to 1.2, the occurrence of streak failure and vertical unevenness failure can be further suppressed, and an infrared shielding film excellent in appearance can be obtained. The coating amount ratio is more preferably 0.8 to 1.2.

In a preferred embodiment of the present invention, the coating amount of the lowest layer of the high refractive index layer coating solution or coating solution for low refractive index layer is preferably from ^{10~40g / m 2, 10~30g / m} 2 is more preferable. The lowermost layer is a layer that is in direct contact with the base film, and the disturbance of the application surface of the lowermost layer tends to affect streak failure and vertical unevenness failure. Therefore, when the coating amount of the lowermost coating liquid is in the range of 10 to 40 g / m ² , it is more effective for suppressing streak failure and vertical unevenness failure.

  In the production method of the present invention, the coating speed is preferably 60 to 200 m / min, and more preferably 80 to 200 m / min. According to the production method of the present invention, it is possible to obtain an infrared shielding film excellent in appearance with suppressed streak failure and vertical unevenness failure even at such a high speed.

  In the drying method, the coating liquid for the high refractive index layer and the coating liquid for the low refractive index layer are heated to 30 to 60 ° C., and the coating liquid for the high refractive index layer and the coating liquid for the low refractive index layer are formed on the base film. After the simultaneous multilayer coating is performed, the temperature of the formed coating film is preferably cooled (set) to preferably 1 to 15 ° C. and then dried at 10 ° C. or higher. More preferable drying conditions are wet bulb temperature −10 to 50 ° C. and film surface temperature 10 to 50 ° C. For example, it is dried by blowing warm air of 50 ° C. for 1 to 5 minutes. Moreover, as a cooling method immediately after application | coating, it is preferable to carry out by a horizontal set system from a viewpoint of the uniformity improvement of the formed coating film.

  As a drying method, warm air drying, infrared drying, and microwave drying are used. In addition, drying in a multi-stage process is preferable to drying in a single process, and it is more preferable to set the temperature of the constant rate drying section <the temperature of the rate-decreasing drying section. In this case, the temperature range of the constant rate drying section is preferably 20 to 60 ° C, and the temperature range of the decreasing rate drying section is preferably 45 to 80 ° C.

  Here, the set means that the viscosity of the coating composition is increased by means such as lowering the temperature by applying cold air or the like to the coating film, the fluidity of the substances in each layer and in each layer is reduced, or the gel It means the process of making it. A state in which the cold air is applied to the coating film from the surface and the finger is pressed against the surface of the coating film is defined as a set completion state.

  The time (setting time) from the time of application to the completion of setting by applying cold air is preferably within 5 minutes, and more preferably within 2 minutes. Further, the lower limit time is not particularly limited, but it is preferable to take 30 seconds or more. With such a set time, the components in the layer are sufficiently cooled, the interlayer diffusion of the metal oxide particles is suppressed, and the difference in refractive index between the high refractive index layer and the low refractive index layer is sufficient. .

[Base film]
As the base film of the infrared shielding film, various resin films can be used. For example, polyolefin film (polyethylene, polypropylene, etc.), polyester film (polyethylene terephthalate, polyethylene naphthalate, etc.), polyvinyl chloride, 3 acetic acid A cellulose etc. are mentioned. A polyester film is preferred. Although it does not specifically limit as a polyester film, It is preferable that it is a polyester film 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. Of these, polyesters mainly composed of polyethylene terephthalate and polyethylene naphthalate, copolymer 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 base film used in the present invention is preferably 10 to 300 μm, and more preferably 20 to 150 μm. In addition, the two base films may be stacked, and in this case, the type may be the same or different.

  Moreover, it is preferable that the transmittance | permeability of the visible region shown by JISR3106: 1998 is 85% or more, and, as for the base film which concerns on this invention, it is more preferable that it is 90% or more. If it is the range of such a transmittance | permeability, it will become advantageous for the transmittance | permeability of visible region shown by JISR3106: 1998 when it is set as an infrared shielding film to be 40% or more, and is preferable.

  The base film according to the present invention can be produced by a conventionally known general method. For example, an unstretched substrate film that is substantially amorphous and not oriented can be produced by melting a resin as a material with an extruder, extruding it with an annular die or a T-die, and quenching. Further, the unstretched base film is uniaxially stretched, tenter-type sequential biaxial stretch, tenter-type simultaneous biaxial stretch, tubular-type simultaneous biaxial stretch, and other known methods such as the base film flow (vertical axis) direction. Alternatively, a stretched substrate film can be produced by stretching in a direction perpendicular to the flow direction of the substrate film (horizontal axis). The draw ratio in this case can be appropriately selected according to the resin used as the raw material of the base film, but is preferably 2 to 10 times in the vertical axis direction and the horizontal axis direction.

  As described above, the base film may be an unstretched film or a stretched film, but a stretched film is preferable from the viewpoint of improving the strength and suppressing thermal expansion.

  Moreover, the base film according to the present invention may be subjected to relaxation treatment or offline heat treatment in terms of dimensional stability. It is preferable that the relaxation treatment is performed in a process from the heat setting in the stretching process of the polyester film to the winding in the transversely stretched tenter or after exiting the tenter. The relaxation treatment is preferably performed at a treatment temperature of 80 to 200 ° C, more preferably 100 to 180 ° C. Moreover, it is preferable that the relaxation rate is 0.1 to 10% in both the longitudinal direction and the width direction, and more preferably, the relaxation rate is 2 to 6%. The base film subjected to the relaxation treatment is improved in heat resistance by the above-described offline heat treatment, and further has good dimensional stability.

In the base film according to the present invention, it is preferable to apply the undercoat layer coating solution inline on one side or both sides in the film forming process. In the present invention, undercoating during the film forming process is referred to as in-line undercoating. Examples of resins used in the undercoat layer coating solution useful in the present invention include polyester resins, acrylic-modified polyester resins, polyurethane resins, acrylic resins, vinyl resins, vinylidene chloride resins, polyethyleneimine vinylidene resins, polyethyleneimine resins, and polyvinyl alcohol resins. , Modified polyvinyl alcohol resin, gelatin and the like can be used, and these can be used alone or in combination of two or more. A conventionally well-known additive can also be added to these undercoat layers. The undercoat layer can be coated by a known method such as roll coating, gravure coating, knife coating, dip coating or spray coating. The coating amount of the undercoat layer is preferably about 0.01 to ² g / m ² (dry state).

[Optical reflector]
The optical reflection film provided by the present invention can shield light having a predetermined wavelength by controlling the optical film thickness and the like of the laminate, so that various optical reflectors can be used depending on the light to be shielded. It can be applied for use. For example, an ultraviolet shielding body using an ultraviolet shielding film that reflects ultraviolet light, a decorative body using a light-colored film that reflects visible light, an infrared shielding body using an infrared shielding film that reflects infrared light, a predetermined wavelength And a decorative body using a metallic glossy film that reflects the light.

  Also in the following description, although the infrared shielding body using the infrared shielding film which is a typical example as an optical reflection film is demonstrated, this invention is not limited.

[Infrared shield]
The infrared shielding film according to this embodiment can be applied to a wide range of fields. For example, as a film for window pasting such as heat ray reflective film that gives heat ray reflection effect, film for agricultural greenhouses, etc. It is mainly used for the purpose of improving weather resistance. Moreover, it is used suitably also as an infrared shielding film for motor vehicles pinched | interposed between glass, such as laminated glass for motor vehicles. In this case, since the infrared shielding film can be sealed from outside air gas, it is preferable from the viewpoint of durability.

  Especially the infrared shielding film which concerns on this form is used suitably for the member bonded by base | substrates, such as glass or glass substitute resin, directly or through an adhesive or an adhesive agent. A laminate of the infrared shielding film and the substrate is also called an infrared shielding body.

  Specific examples of the substrate include, for example, glass, polycarbonate resin, polysulfone resin, acrylic resin, polyolefin resin, polyether resin, polyester resin, polyamide resin, polysulfide resin, unsaturated polyester resin, epoxy resin, melamine resin, Examples thereof include phenol resin, diallyl phthalate resin, polyimide resin, urethane resin, polyvinyl acetate resin, polyvinyl alcohol resin, styrene resin, vinyl chloride resin, metal plate, ceramic and the like. The type of the resin may be any of a thermoplastic resin, a thermosetting resin, and an ionizing radiation curable resin, and these may be used alone or in combination of two or more. The substrate that can be used in the present invention can be produced by a known method such as extrusion molding, calendar molding, injection molding, hollow molding, compression molding and the like.

  The thickness of the substrate is not particularly limited, but is usually 0.1 mm to 5 cm.

  The adhesive (adhesive layer) for bonding the infrared shielding film and the substrate according to this embodiment is preferably installed so that the infrared shielding film is on the sunlight (heat ray) incident surface side. Moreover, it is preferable to sandwich the infrared shielding film according to the present embodiment between the window glass and the base because it can be sealed from surrounding gas such as moisture and has excellent durability. Even if the infrared shielding film according to this embodiment is installed outdoors or on the outside of a vehicle (for external application), it is preferable because of environmental durability.

  An adhesive (adhesive layer) may be used to bond the infrared shielding film according to this embodiment and the substrate. As this adhesive, 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, a solvent system is preferable in the acrylic adhesive because the peel strength can be easily controlled. When a solution polymerization polymer is used as the acrylic solvent adhesive, a known monomer 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 | system | group resin as said adhesion layer or an adhesion layer. Specific examples thereof include, for example, plastic polyvinyl butyral (manufactured by Sekisui Chemical Co., Ltd.), ethylene-vinyl acetate copolymer (manufactured by DuPont, Takeda Pharmaceutical Co., Ltd., duramin), modified ethylene-vinyl acetate copolymer And the like (Mersen (registered trademark) G manufactured by Tosoh Corporation). In the adhesive layer or the adhesive layer, an ultraviolet absorber, an antioxidant, an antistatic agent, a heat stabilizer, a lubricant, a filler, a colorant, an adhesion (adhesion) adjusting agent, and the like may be appropriately added and blended.

  Preferred examples of the substrate include a plastic substrate, a metal substrate, a ceramic substrate, and a cloth substrate. The infrared shielding film of this embodiment is applied to a substrate of various forms such as a film, a plate, a sphere, a cube, and a cuboid. Can be provided. Among these, a plate-shaped ceramic base is preferable, and an infrared shielding body in which an infrared shielding film of this embodiment is provided on a glass plate is more preferable. As an example of a glass plate, the float plate glass described in JISR3202: 1996 and polished plate glass are mentioned, for example, As glass thickness, 0.01 mm-20 mm are preferable.

  As a method for providing the infrared shielding film according to the present embodiment on the substrate, a method in which an adhesive layer is coated on the infrared shielding film as described above, and is attached to the substrate via the adhesive layer or the adhesive layer is suitably used. . As a bonding method, dry bonding in which a film is directly bonded to a substrate, water bonding as described above, and the like can be applied, but in order to prevent air from entering between the substrate and the infrared shielding film. Moreover, it is more preferable to bond by the water sticking method from the viewpoint of ease of construction such as positioning of the infrared shielding film on the substrate.

  In addition, the infrared shielding body according to the present embodiment may be, for example, a form in which infrared shielding films are provided on both surfaces of glass, or an adhesive layer or an adhesive layer is provided on both surfaces of the infrared shielding film, and infrared shielding is performed. A laminated glass-like form in which glass is bonded to both sides of the film may be used.

  Insulation performance and solar heat shielding performance of the infrared shielding film or infrared shield are generally JIS R3209: 1998 (multi-layer glass), JIS R3106: 1998 (transmittance, reflectance, emissivity, solar radiation of plate glass). Heat acquisition rate test method), JIS R3107: 1998 (a method for calculating the thermal resistance of sheet glass and the heat transmissivity of buildings).

  Measurements of solar transmittance, solar reflectance, emissivity, and visible light transmittance are as follows: (1) Using a spectrophotometer having a wavelength (300 to 2500 nm), the spectral transmittance and spectral reflectance of various single glass plates are measured. . Further, the emissivity is measured using a spectrophotometer having a wavelength of 5.5 to 50 μm. In addition, a predetermined value is used for the emissivity of float plate glass, polished plate glass, mold plate glass, and heat ray absorbing plate glass. (2) The solar transmittance, the solar reflectance, the solar absorption rate, and the modified emissivity are calculated according to JIS R3106: 1998 by calculating the solar transmittance, the solar reflectance, the solar absorption rate, and the vertical emissivity. The corrected emissivity is obtained by multiplying the coefficient shown in JIS R3107: 1998 by the vertical emissivity. The heat insulation and solar heat shielding properties are calculated by (1) calculating the thermal resistance of the double glazing according to JIS R3209: 1998 using the measured thickness value and the corrected emissivity. However, when the hollow layer exceeds 2 mm, the gas thermal conductance of the hollow layer is determined according to JIS R3107: 1998. (2) The heat insulation is obtained by adding a heat transfer resistance to the heat resistance of the double-glazed glass and calculating the heat flow resistance. (3) Solar heat shielding properties are calculated by obtaining the solar heat acquisition rate according to JIS R3106: 1998 and subtracting from 1.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated still in detail, this invention is not limited to these Examples at all.

<Example 1>
<Production of infrared shielding film>
[Preparation of coating solution (preparation process)]
(Preparation of coating liquid L1 for low refractive index layer)
To 12 parts by mass of colloidal silica (Snowtex (registered trademark) OXS, manufactured by Nissan Chemical Industries, Ltd., 10% by mass of graphic), polyvinyl alcohol (PVA-I03, polymerization degree 300, saponification degree 98.5 mol%, Co., Ltd.) 2 parts by mass of a 5% by mass aqueous solution of Kuraray Co., Ltd. and 10 parts by mass of a 3% by mass aqueous boric acid solution were added, respectively, and the mixture was heated to 40 ° C. and stirred while polyvinyl alcohol (PVA-117, polymerization degree 1700, Ken 20 mass parts of 5 mass% aqueous solution of degree of conversion 98.5 mol%, manufactured by Kuraray Co., Ltd., and 1 mass part of 1 mass% aqueous solution of surfactant (Rapisol (registered trademark) A30, manufactured by NOF Corporation) were added. Then, 55 parts by mass of pure water was added to prepare a coating solution L1 for a low refractive index layer. However, the amount of pure water was adjusted so that the coating liquid L1 for the low refractive index layer had the viscosity described in Table 1-1 below.

(Preparation of silica-attached titanium oxide sol)
After adding 2 parts by mass of pure water to 0.5 parts by mass of 15.0% by mass titanium oxide sol (SRD-W, volume average particle size 5 nm, rutile titanium oxide particles, manufactured by Sakai Chemical Industry Co., Ltd.), Heated. Next, 1.3 parts by mass of an aqueous silicic acid solution (sodium silicate 4 (manufactured by Nippon Chemical Industry Co., Ltd.) diluted with pure water so that the SiO ₂ concentration becomes 2.0 mass%) was gradually added. . Next, heat treatment was carried out at 175 ° C. for 18 hours in an autoclave, and after cooling, it was concentrated with an ultrafiltration membrane, thereby oxidizing (covering) SiO ₂ having a solid concentration of 20% by mass on the surface. A titanium sol (hereinafter, also simply referred to as “silica-attached titanium oxide sol”) was obtained.

(Preparation of coating liquid H1 for high refractive index layer)
5 masses of polyvinyl alcohol (PVA-103, polymerization degree 300, saponification degree 98.5 mol 1%, manufactured by Kuraray Co., Ltd.) in 30 parts by mass of the silica-attached titanium oxide sol (solid content 20.0 mass%) obtained above. 2 parts by weight of a 2% aqueous solution, 10 parts by weight of a 3% by weight aqueous boric acid solution and 10 parts by weight of a 2% by weight aqueous citric acid solution, respectively, and then heated to 40 ° C. while stirring, polyvinyl alcohol (PVA-617, polymerization) 20 parts by mass of a 5% by weight aqueous solution having a degree of 1700, a degree of saponification of 95.0 mol%, manufactured by Kuraray Co., Ltd., and 1 part by weight of a 1% by weight aqueous solution of a surfactant (RAPISOL A30, NOF Corporation) 27 parts by mass of pure water was added to prepare a cloth liquid H1 for high refractive index layer. However, the amount of pure water was adjusted so that the coating liquid H1 for the high refractive index layer had the viscosity described in Table 1-1 below.

[Distributed processing (circulation process)]
The coating solution for the high refractive index layer and the coating solution for the low refractive index layer obtained as described above were subjected to dispersion treatment in the circulation step. As a dispersing device, a Taihei Koki milder disperser MDN306 was used at a rotational speed of 3000 rpm. In the circulation step, the flow rate of the coating solution fed to the dispersing device was 8 L / min.

[Production of infrared shielding film (simultaneous multilayer coating process)]
Using a slide hopper type coating apparatus capable of coating 40 layers, a polyethylene terephthalate film having a thickness of 50 μm (manufactured by Toyobo Co., Ltd.) while keeping the cloth liquid L1 for low refractive index layer and the coating liquid H1 for high refractive index layer at 40 ° C. , Cosmo Shine (registered trademark) A4300, double-sided easy-adhesion layer), a total of 8 to 40 layers were applied alternately. At this time, the liquid supply tank is added so that the first layer (lowermost layer) and the second layer are the low refractive index layer and the third and subsequent layers are alternately the lower refractive index layer from the base film side. The coating solution was fed to a slide hopper type coating device. When the flow rate was confirmed by a flow meter (FD-SS2A, manufactured by Keyence Corporation) provided between the liquid feed tank and the slide hopper type coating device, the flow rate varied in the liquid feed flow path from the first layer to the top layer. It was confirmed that there was almost no (less than ± 1% of the average flow rate). In this way, an infrared shielding film having a total of 8 to 40 low refractive index layers and high refractive index layers was produced.

  In each example and comparative example, the number of coating layers in the simultaneous multilayer, the viscosity and coating amount of the coating liquid L1 for the low refractive index layer excluding the lowermost layer, the viscosity and coating amount of the cloth liquid H1 for the high refractive index layer, the lowermost layer The coating amount sum and coating amount ratio of the adjacent low refractive index layer and high refractive index layer excluding, the coating amount of the lowermost layer coating solution, the angle of the slide surface with respect to the horizontal plane, the thickness per block, and the coating speed Tables 1-1 and 1-2 show. The viscosity of the coating solution was measured with a drop viscometer. In both the examples and comparative examples, the viscosity of the lowermost layer liquid was 10 mPa · s. Further, in each example and comparative example, all the blocks having the same thickness as shown in Table 1-1 were used. For example, in Example 1, it shows that only the block of thickness 45mm was used.

<Examples 2 to 14>
In Examples 2 to 14, infrared shielding films were produced in the same manner as in Example 1 except that the production conditions described in Table 1-1 were used.

<Comparative Examples 1-14>
In Comparative Examples 1-14, the infrared shielding film was manufactured like Example 1 except having set it as the manufacturing conditions of following Table 1-2.

[Evaluation of infrared shielding film]
About the infrared shielding film manufactured in Examples 1-14 and Comparative Examples 1-14, the following performance evaluation was performed about the visual streak failure and the vertical nonuniformity failure. The vertical unevenness failure was visually observed under sunlight. The evaluation results are shown in Table 2-1 and Table 2-2 below.

(Visual evaluation of streak failure and vertical unevenness failure)
A: Not generated at all O: Slightly generated Δ: Weakly generated ×: Strongly generated

  In addition, as for the infrared shielding film manufactured by the manufacturing method of this invention, as a visual evaluation result of a streak failure and a vertical nonuniformity failure, it is necessary that neither generate | occur | produce strongly ("*"), but generate | occur | produce weakly ("" Δ ”) may be generated, but slight occurrence (“ ◯ ”) is preferred, and no occurrence (“ ◎ ”) is particularly preferred.

  As is apparent from the results of Tables 2-1 and 2-2, the viscosity of the coating solution, the slide surface angle with respect to the horizontal plane, the thickness per block, and the total coating amount of the high refractive index layer and the low refractive index layer In Examples 1 to 14, which are within the predetermined range, streak failure and vertical unevenness failure were improved as compared with Comparative Examples 1 to 14.

1 base film,
2 Back roll,
3 Coater dice,
4 Coating liquid,
5 vacuum chamber,
6 Wetted parts,
7 The angle between the center of the back roll and the wetted part,
8 The angle of the slide surface relative to the horizontal plane,
9 Angle between the running surface of the base film and the sliding surface,
10 decompression section,
11 Block 31 Stator teeth,
32 rotor teeth,
34, 35 Liquid to be sheared,
A upper layer liquid,
B lower layer liquid,
t block thickness,
La shear gap.

Claims (5)

Optical including a step of simultaneously applying 10 to 40 layers of a coating solution for a high refractive index layer and a coating solution for a low refractive index layer on a continuously running substrate film using a slide hopper coating device A method of manufacturing a reflective film,
The viscosity at 40 ° C. of the high refractive index layer coating liquid and the low refractive index layer coating liquid is 5 to 200 mPa · s,
The angle of the slide surface of the slide hopper type coating device with respect to the horizontal plane is 2 to 25 °,
The thickness per block of the slide hopper type coating device is 45 to 60 mm,
The total coating amount of the coating solution for the high refractive index layer and the coating solution for the low refractive index layer of the adjacent high refractive index layer and the low refractive index layer excluding the lowermost layer formed by the simultaneous multilayer coating is 11 to 11. The manufacturing method of the optical reflection film which is 16 g / m < ² >. The number of layers to be coated simultaneously is 10 to 34 layers, and the sum of the coating amounts is 12 to 15 g / m ² , and the adjacent high refractive index coating layer and the low refractive index coating layer excluding the lowermost layer are high. 2. The production method according to claim 1, wherein a coating amount ratio (high refractive index layer / low refractive index layer) of the coating liquid for the refractive index layer and the coating liquid for the low refractive index layer is 0.7 to 1.2.   The manufacturing method according to claim 1 or 2, wherein the number of layers to be coated simultaneously is 10 to 26 layers. The manufacturing method of any one of Claims 1-3 whose application amount of the coating liquid for the high refractive index layer or the coating liquid for the low refractive index layer in the lowermost layer is 10 to 40 g / m ² .   The manufacturing method of any one of Claims 1-4 whose coating speed in the said simultaneous multilayer coating is 60-200 m / min.