JP2012027287A - Near-infrared reflection film and near-infrared reflector having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a near-infrared reflection layered film which is uniform and has good transparency for a visible light region while having a desired near-infrared reflection performance, and induces no wrinkle or crack when used to constitute a laminated glass and the like, for use in a near-infrared reflection film including a near infrared reflection layered film comprising two adjoining layers having mutually different refractive indices on a transparent support, and to provide a near-infrared reflection film.SOLUTION: A near-infrared reflection film and a near infrared reflector are provided, having the following features. The near-infrared reflection film includes a near infrared reflection layered film which is produced by layering, on a transparent support, a unit comprising two adjoining layers having mutually different refractive indices in a wavelength range from 750 to 1400 nm, with the difference in the refractive index between the layers being 0.3 or more. When the near-infrared reflection layered film is subjected to a flex resistance test described in JIS K5600-5-1 (by cylindrical mandrel method), the diameter of a mandrel is 30 mm or less when the near-infrared reflection layered film starts to crack or starts to peel from the transparent support.

Description

  The present invention relates to a near-infrared reflective laminated film excellent in visible light transmittance, infrared (heat ray) reflectivity, and electromagnetic wave permeability, and a near-infrared reflective laminated film used for vehicle window glass, architectural window glass, and the like. It is related with the near-infrared reflective film containing and the near-infrared reflector provided with the same.

  In general, it is theoretically supported that a laminated film in which a high refractive index layer and a low refractive index layer are alternately laminated by adjusting the respective optical film thicknesses selectively reflects light of a specific wavelength. It is used as a laminated film that transmits visible light and selectively reflects near-infrared rays as a heat-ray shielding reflective film used for windows of buildings, vehicle members, and the like.

  As a method for producing a laminated film, a method has been reported in which each layer is sequentially formed on a transparent support by a dry film-forming method such as vapor deposition or sputtering (for example, see Patent Document 1). ), Any of the dry film forming methods has a problem in that the production cost is high, it is difficult to increase the area, and usable materials and substrates are limited to those having heat resistance.

  On the other hand, the wet (wet) film-forming method by solution coating has advantages that the manufacturing cost is low and the area is relatively easily increased. Apply intermediate layer by dip coating method, which is a kind of wet coating, or apply weekly drying by transfer printing method, then dry with hot air, apply high refractive index layer on it, dry and then baked two layers simultaneously However (see, for example, Patent Document 2), there is no mention of coating more than two layers.

  A heat ray blocking member is obtained by alternately laminating 6 or more layers of a solution for a low refractive index layer having a refractive index of 1.5 or 1.27 or less and a solution for a high refractive index layer on a transparent PET film (for example, As a coating means, although a wet film forming method such as a bar coater is mentioned as a coating means, the manufacturing cost cannot be sufficiently reduced for coating one layer at a time, and the smoothness of the coating film as the number of layers increases. As a result, it is difficult not only to obtain a uniform laminated film but also to deteriorate the adhesion between the layers.

  Using a wet coating method to form a laminate of 7 layers or less composed of a heat ray shielding film having excellent interlayer adhesion by making the low refractive index layer and the high refractive index layer a resin layer containing a binder. (For example, refer to Patent Document 4). In this case, the method cited as a wet coating method is a spin coating method or the like. In addition, there is a problem that the manufacturing cost cannot be sufficiently reduced, and it becomes difficult to obtain a uniform and transparent laminated film as the number of layers increases.

  On the other hand, when a laminated glass is produced by sandwiching a plastic film with an infrared reflecting film between intermediate films, a low refractive index dielectric film and a high refractive index dielectric film are alternately laminated in four to eleven layers. When the heat condensing rate of the infrared reflective film is in the range of 0.5 to 3% in the temperature range of 90 ° C. to 150 ° C., in the case of a curved glass plate, the plastic film is wrinkled, resulting in appearance defects. (For example, refer to Patent Document 5), however, the infrared reflective film disclosed in this document cannot sufficiently prevent the occurrence of actual cracks.

JP-A-7-246366 JP-A-6-345488 Japanese Patent Laid-Open No. 2003-266577 JP 2009-86659 A JP 2009-35438 A

  An object of the present invention is to provide a near-infrared reflective film including a near-infrared reflective laminated film formed by laminating units composed of two adjacent layers having different refractive indexes on a transparent support, at a low cost. However, the near-infrared reflective laminated film and near-red, which have the desired near-infrared reflection performance, are uniform and have good transparency in the visible light region, and do not cause wrinkles or cracks when laminated glass is used. An object of the present invention is to provide a near-infrared reflective film including an outer reflective laminated film and a near-infrared reflector provided with the same.

  The above object of the present invention can be achieved by the following configuration.

  1. Near red formed by laminating two units of adjacent layers having different refractive indexes in the wavelength range of 750 to 1400 nm on the transparent support and having a difference in refractive index of both layers of 0.3 or more. A near-infrared reflective film having an outer reflective laminated film, wherein the near-infrared reflective film is subjected to a bending resistance test (cylindrical mandrel method) described in JIS K5600-5-1. However, the diameter of the mandrel that begins to crack or peel off from the transparent support is 30 mm or less.

  2. 2. The near-infrared reflective film as described in 1 above, wherein the near-infrared reflective laminated film is formed by a unit laminated by simultaneous multilayer coating.

  3. 3. The near-infrared reflective film as described in 1 or 2 above, wherein the near-infrared reflective laminated film is formed of two or more units laminated by simultaneous multilayer coating.

  4). 4. The infrared reflective film as described in any one of 1 to 3 above, wherein the near-infrared reflective laminated film is formed of three or more units laminated by simultaneous multilayer coating.

  5. The near-infrared reflective laminated film contains at least one selected from metal oxides or inorganic fine particles and polyvinyl alcohol in at least one layer of a unit forming the near-infrared reflective laminated film, and includes at least two or more 5. The near-infrared reflective film according to any one of 1 to 4 above, which is formed by laminating units.

  6). The near-infrared reflective laminate film has an average particle size as a metal oxide in a layer having a higher refractive index in the wavelength range of 750 to 1400 nm than the other layers of the unit forming the near-infrared reflective laminate film. 6. The near-infrared reflective film as described in any one of 1 to 5 above, comprising titanium oxide particles having a diameter of 100 nm or less and polyvinyl alcohol.

  7). The near-infrared reflective laminated film has an average particle size as inorganic fine particles in a layer having a lower refractive index in the wavelength range of 750 to 1400 nm than the other layers of the unit forming the near-infrared reflective laminated film. The near-infrared reflective film as described in any one of 1 to 6 above, comprising silica particles of 100 nm or less and polyvinyl alcohol.

  8). 8. A near-infrared reflector, wherein the near-infrared reflective film according to any one of 1 to 7 is provided on at least one surface of a substrate.

  According to the present invention, in a near-infrared reflective film including a near-infrared reflective laminated film formed by laminating units composed of two adjacent layers having different refractive indexes on a transparent support, at a low cost. However, the near-infrared reflective laminated film and near-red, which have the desired near-infrared reflection performance, are uniform and have good transparency in the visible light region, and do not cause wrinkles or cracks when laminated glass is used. A near-infrared reflective film including an outer reflective laminated film and a near-infrared reflector provided with the same can be provided.

  The best mode for carrying out the present invention will be described in detail below, but the present invention is not limited thereto.

  Near-infrared reflective laminated film excellent in visible light transmittance, infrared (heat ray) reflectivity, and electromagnetic wave transmittance, and near infrared including this near-infrared reflective laminated film, used for vehicle window glass, architectural window glass, etc. When trying to obtain a reflective film, conventionally, a near-infrared reflective laminated film was produced using a sputtering method without using a binder resin or a resin cured with heat or UV. When produced, defects such as cracks were generated in the near-infrared reflective laminated film. In addition, it is difficult to increase the area by sputtering, and conventional knowledge suggests that if a multilayer coating can be applied simultaneously using a hydrophilic binder, it would be large and reduce manufacturing costs. In order to obtain the above, it is necessary to increase the difference in refractive index as much as possible or to increase the number of layers to be stacked, and to form a unit composed of two different adjacent layers to form a near-infrared reflective layer. The actual situation is that the composition of the possible high-refractive index layer and low-refractive index layer and the composition of the entire layer were not obtained. As a result of intensive investigations on this point, the present invention forms a unit composed of two adjacent layers having different refractive indexes on a transparent support to form a near-infrared reflective layer, and a wavelength range of 750 to 1400 nm of both layers. While applying a multilayer coating in a water system using a hydrophilic binder while making the difference in refractive index at least 0.3 or more, a good multilayer coating can be performed, but the so-called web is conveyed at high speed after coating. It is difficult to dry the coating film without causing slippage or flow. At this time, when polyvinyl alcohol is used as the hydrophilic binder, it is possible to perform good and stable simultaneous multilayer coating including the drying step, and JIS K5600- According to the bending resistance test (cylindrical mandrel method) described in 5-1, the near-infrared reflective laminated film is cracked or peeled off from the transparent support. This is based on the fact that it has been found that a near-infrared reflective film including a near-infrared reflective laminated film having uniform optical properties can be finally produced by making the composition of the mandrel to be started to have a diameter of 30 mm or less. .

  The near-infrared reflective film of the present invention includes a near-infrared reflective laminated film formed by laminating units composed of two adjacent layers having different refractive indexes on a transparent support, and includes JIS R-3106- The transmittance in the visible light region indicated by 1998 is 50% or more, and the region having a wavelength of 750 nm to 1400 nm exceeds the reflectance of 50%.

[Support]
As a transparent support that can be used for the near-infrared reflective film of the present invention, the visible light region with a wavelength of 400 nm to 750 nm, and the light transmittance in the near-infrared region up to 1400 nm on the longer wave side thereof are good, Any flexible film that is stable to light and heat may be used. For example, various resins can be used, such as polycarbonate resin, polysulfone resin, acrylic resin, polyolefin resin, polyether resin, polyester resin, polyamide resin, polysulfide resin, unsaturated polyester resin, Epoxy resin, melamine resin, phenol resin, diallyl phthalate resin, polyimide resin, urethane resin, polyvinyl acetate resin, polyvinyl alcohol resin, styrene resin, vinyl chloride resin, fiber resin, etc. These may be used as a mixture of two or more thereof.

  As a preferable transparent support that can be used in the present invention, polyolefin films (polyethylene, polypropylene, etc.), polyester films (polyethylene terephthalate, polyethylene naphthalate, etc.), polyvinyl chloride, cellulose acetate, etc. can be used. Is a polyester film. 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.

  Various additives may be added to the transparent support of the present invention for the purpose of maintaining the effect of the heat ray shielding film, such as a heat stabilizer, an ultraviolet absorber, an antioxidant, an antiseptic and an antifungal agent. Furthermore, various additives may be added for the purpose of imparting further functions such as a coloring agent such as a dye or pigment that absorbs or reflects a specific wavelength of visible light, near-infrared light, or infrared light, or a coloring agent such as a dye, or inorganic oxide fine particles.

  The glass transition temperature (Tg) of the transparent support of the present invention is not particularly limited as long as the effects of the present invention are not impaired, but is usually 60 to 500 ° C, preferably 80 to 300 ° C, more preferably 100 to 300 ° C. It is. Here, when Tg is lower than 60 ° C., the laminate is deformed during long-term use, and the selective reflection wavelength changes, which is not preferable. When Tg is higher than 500 ° C., it is not preferable because it easily breaks against the generation of internal stress and strain.

The linear thermal expansion coefficient of the transparent support of the present invention is not particularly limited as long as the effects of the present invention are not impaired, but is usually preferably 20 × 10 ⁻⁵ / K or less, and more preferably 10 × 10 ⁻⁵ / K or less. If the linear thermal expansion coefficient is larger than this, the amount of deformation at a high temperature is large and distorted. Although there is no restriction | limiting in particular about the minimum of a linear thermal expansion coefficient, Usually, it is 1 * 10 < ^-7 > / K or more. If it is smaller than this, the heat ray shielding film may be peeled off from the substrate, which is not preferable.

  The thickness of the transparent support of the present invention is preferably 40 to 300 μm, particularly 50 to 200 μm. The film support of the present invention may be a laminate of two sheets, and in this case, the type may be the same or different. If it is thinner than 40 μm, it is difficult to handle the film and it is easy to curl due to the stress of the hard coat layer or the infrared reflecting film. The visible light transmittance of the transparent support of the present invention is preferably 90% or more, more preferably 95% or more.

《Near-infrared reflective film》
Next, the near-infrared reflective film formed by laminating | stacking the unit of the 2 layer structure of this invention formed on a transparent support body is demonstrated.

  In the unit of the present invention, the difference in refractive index between two adjacent layers having different refractive indexes is preferably larger if a desired near-infrared reflection performance is to be obtained with a unit having a small number of stacked layers, which results in a low manufacturing cost. In the wavelength range of 750 to 1400 nm, which is the wavelength region of the heat ray to be shielded in the present invention, it is necessary that the value is 0.3 or more. However, from the restriction | limiting on the application | coating mentioned later and the performance at the time of setting it as a laminated glass finally, 0.3 or more and 0.6 or less are preferable, and 0.4 or more and 0.55 or less are more preferable. At this time, the refractive index of the high refractive index layer, which is the higher layer of the two adjacent layers than the other layers, is preferably 1.80 or more and 1.95 or less, and 1.85 or more and 1 More preferably, it is 90 or less. Of the two adjacent layers, the refractive index of the low refractive index layer, which is the lower layer than the other layers, is preferably 1.4 or more and 1.55 or less, and is 1.45 or more and 1.50 or less. It is more preferable that The refractive index can be measured with a multiwavelength Abbe refractometer, a prism coupler, a Mickelson interferometer, a spectroscopic ellipsometer, or the like.

  The near-infrared transmittance of the near-infrared reflective film of the present invention is usually 80% or less, preferably 70% or less, more preferably 65% or less, and still more preferably 60% or less. Is higher than this, it is not preferable because the selective reflectivity of near infrared rays is low. The lower limit is not particularly limited, but is usually 0.1% or more.

  The selective transmittance determined by the ratio of the visible light transmittance to the near infrared transmittance of the near infrared reflective film of the present invention is usually 1.05 or more, preferably 1.10 or more. If the selective transmittance is lower than 1.05, the visible light transmittance is increased, so that the infrared transmittance is also increased, and the light shielding property and the heat shielding property are insufficient. In addition, although there is no restriction | limiting in particular about the upper limit of this selective permeability, Usually, it is 10 or less.

  The haze of the near-infrared reflective film of the present invention is usually 0.05 to 20%, preferably 0.1 to 10%, more preferably 0.5 to 5%. If the haze is lower than 0.05%, it is not preferable because it is difficult to stably produce a near-infrared reflective film with a large area. If the haze is higher than 20%, the use is limited, which is not preferable.

  In the present invention, the film thicknesses of two adjacent layers having different refractive indexes are usually 5 to 1000 nm, more preferably 20 to 600 nm, respectively, for the high refractive index layer and the low refractive index layer of the unit. More preferably, it is 40-300 nm. If the film thickness is thinner than 5 nm, the surface roughness becomes large and the selective reflectivity tends to be lowered, which is not preferable. Further, it is not preferable because it becomes difficult to control the film thickness during manufacturing. When the film thickness is thicker than 1000 nm, a layer containing inorganic particles is not preferable because multiple scattering in the film increases and transparency decreases.

  In the present invention, the surface layer of the two adjacent layers having different refractive indexes is preferably a high refractive index layer. The interface between the high refractive index layer and the low refractive index layer may be completely separated, or the high refractive index layer material and the low refractive index layer material may be mixed at the interface. However, the thickness of the mixed layer at this time is preferably 10% or less with respect to the thickness of the high refractive index layer. If the mixed layer is thicker than this, the reflectance is lowered, which is not preferable.

  In the present invention, the number of stacked layers of two adjacent layers having different refractive indexes is derived from the number of layers required to obtain a desired reflectance in the wavelength range of 750 to 1400 nm by the above-described formula. Or less, preferably 3 or more and 8 or less.

  The infrared reflective film of the present invention is a unit composed of two adjacent layers having different refractive indexes, or a plurality of these units stacked, and if necessary, various layers may be further formed as a single layer or a plurality of layers. Alternatively, it is superposed on the upper layer and all of them are coated on the transparent support at one time or divided into a plurality of times, and are coated and dried by the simultaneous multi-layer method, but the coating method at this time is curtain coating or A slide bead coating method using a hopper is preferably used. In the case of winding after coating and drying while continuously transporting using a long support, it is preferable to wind the coating surface outward. In the case of producing by coating and drying divided into a plurality of times, the plurality of times of coating can be performed on both sides of the transparent support.

  In the near-infrared reflective film of the present invention, the difference in refractive index between the adjacent high refractive index layer and low refractive index layer is 0.3 or more. When there are a plurality of units each composed of a refractive index layer as described above, it is preferable that all refractive index layers satisfy the requirements defined in the present invention. However, the outermost layer may be configured outside the requirements defined in the present invention.

  In order to perform simultaneous multilayer coating, the viscosity of each layer coating solution is preferably in the range of 5 to 100 mPa · s, more preferably 10 to 50 mPa · s when the slide bead coating method is used. In the case of the curtain coating method, the range of 5 to 1200 mPa · s is preferable, and more preferably 25 to 500 mPa · s.

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

  In order to adjust the viscosity of the coating solution for each layer, it is preferable to use a thickener. The thickener is not particularly limited as long as it has a thickening effect that increases the viscosity of the liquid after the addition as compared to before the addition, for example, an organic amide compound, a modified castor oil derivative, Examples thereof include modified polyolefin wax-based materials and organic clay derivatives, thickening polysaccharides, cellulose and cellulose derivatives. In particular, thickening polysaccharides are preferable because they can effectively function to make the surface layer coating film uniform.

  As a coating and drying method, the high refractive index layer coating solution and the low refractive index layer coating solution are heated to 30 ° C. or more, and after coating, the temperature of the formed coating film is once cooled to 1 to 15 ° C. The drying is preferably performed at 10 ° C. or more, and more preferably, the drying conditions are wet bulb temperature 5 to 50 ° C. and film surface temperature 10 to 50 ° C. Moreover, as a cooling method immediately after application | coating, it is preferable to carry out by a horizontal set system from a viewpoint of the formed coating-film uniformity.

  In order to promote gelation at low temperature, a water-soluble anionic polymer such as carboxymethyl cellulose and acrylic acid grafted starch is pre-coated on the surface of the transparent support, sodium lauryl sulfate, or dioctyl sodium sulfosuccinate. A mixture of sodium benzoate and the like may be added to the coating solution. It is also effective to use these in combination with a surfactant such as calcium dodecylbenzene sulfonate and polyalkylene glycol ether.

  In order to prevent defects such as cracks when producing laminated glass by directly sandwiching the infrared reflective film of the present invention or an intermediate film such as a polyvinyl butyral sheet or an ethylene vinyl acetate copolymer resin sheet, JIS K5600-5 It is necessary that the near-infrared reflective laminated film is cracked by the bending resistance test (cylindrical mandrel method) described in -1, or the mandrel starting to peel from the transparent support has a diameter of 30 mm or less. . In order to set the above range, the mass ratio of the binder resin to the metal oxide particles in the high refractive index layer of the present invention is 3 to 18%, and the mass ratio of the binder resin to the inorganic particles in the low refractive index layer of the present invention is It is realizable by setting it as 5 to 20%.

  Also, within this range, good coating and drying properties can be achieved while satisfying the above-described conditions that the refractive index of the high refractive index layer and the low refractive index layer and the difference in refractive index of both layers are 0.3 or more. It was found that a near-infrared reflective film having a near-infrared reflective laminated film having uniform optical characteristics can be obtained.

  In the present invention, the minimum transmittance in the wavelength region of 750 to 1300 nm of the near-infrared reflective laminated film is preferably 90% or less. If the minimum transmittance exceeds 90%, the heat shielding property becomes insufficient, which is not preferable. This minimum transmittance is preferably 80% or less, more preferably 70% or less, and still more preferably 65% or less. The lower limit of the minimum transmittance is usually 5% or more, preferably 10% or more.

  The visible light transmittance of the near-infrared reflective film of the present invention is usually 50 to 99%, preferably 60 to 99%, more preferably 70 to 99%, and further preferably 80 to 98%.

The metal oxide that can be used in the high refractive index layer of the present invention is preferably fine particles having a smaller particle diameter because of the necessity of providing higher and uniform reflection characteristics. Examples of such metal oxide fine particles include TiO ₂ (titanium oxide), SiO ₂ , ZrO ₂ , Al ₂ O ₃ , ZnO, Sb ₂ O ₃ , ZrSiO ₄ , and zeolite. In addition, these fine particles are subjected to surface treatment or are subjected to surface treatment from the viewpoint of improving dispersibility and stability in the case of using a fine particle dispersion described later for inclusion in the high refractive index layer. It can be judged whether to use a non-existing one. Specific materials for the surface treatment in the case of performing the surface treatment include heterogeneous metal oxides such as zirconium oxide and silicon oxide, metal hydroxides such as aluminum hydroxide, organic acids such as organosiloxane and stearic acid. Can be mentioned. These may be used individually by 1 type and may be used in combination of multiple types. From the viewpoint of the stability of the fine particle dispersion described later for forming the high refractive index layer, the surface treatment material is preferably a dissimilar metal oxide and / or metal hydroxide, and among these, a metal hydroxide is particularly preferable.

  When metal oxide fine particles are surface-coated with these materials, the coating amount (generally, the coating amount is indicated by the mass ratio of the surface treatment material used on the surface of the fine particles to the mass of the fine particles). .) Is preferably 0.01 to 99% by mass. If the coating amount is too small, the effect of improving the dispersibility and stability due to the surface treatment cannot be obtained sufficiently, which is not preferable. If the coating amount is too large, the refractive index of the high refractive index layer is lowered, and as a result, the two adjacent layers are not. The difference in refractive index is reduced, and the number of stacked units of the present invention is increased, resulting in a high production cost.

  The refractive index of the metal oxide fine particles contained in the high refractive index layer is preferably 1.65 or more in a bulk state, more preferably 1.75 or more, and further preferably 2.0 or more. More preferably, it is 2.5 or more. Moreover, it is preferable that it is 3.0 or less. If the refractive index of the metal oxide fine particles is lower than 1.65, the near-infrared transmittance in the near-infrared reflective laminated film is increased, which is not preferable. If the refractive index of the metal oxide fine particles is higher than 3.0, multiple scattering in the film increases and transparency is lowered, which is not preferable.

  The particle size of the metal oxide fine particles contained in the high refractive index layer is usually preferably 5 nm or more, more preferably 20 nm or more, and further preferably 30 nm or more. Moreover, it is preferable that it is 70 nm or less, it is more preferable that it is 60 nm or less, and it is still more preferable that it is 50 nm or less. When the particle size of the inorganic particles is smaller than 5 nm, the inorganic particles are likely to aggregate and the transparency is rather lowered, which is not preferable. Further, if the particle size is small, the surface area is increased, the catalytic activity is increased, and deterioration of the high refractive index layer or an adjacent layer may be promoted, which is not preferable. If the particle size of the inorganic particles is larger than 70 nm, it is not preferable because the transparency of the high refractive index layer is lowered. As long as the effects of the present invention are not impaired, the particle size distribution is not limited and may be wide or narrow and may have a plurality of distributions.

  The metal oxide content in the high refractive index layer is preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably 85% by mass or more. Moreover, it is preferable that it is 97 mass% or less, and it is more preferable that it is 95 mass% or less. When the metal oxide content of the high refractive index layer is less than 70% by mass, it is substantially difficult to set the refractive index of the high refractive index layer to 1.80 or more. When the content of the inorganic particles in the high refractive index layer is more than 95% by mass, it is not preferable because aqueous coating of the high refractive index layer becomes difficult, the brittleness of the film after drying increases, and the bending resistance decreases.

TiO ₂ (titanium dioxide sol) is more preferable from the viewpoint of the stability of the metal oxide particle-containing composition described later for forming the high refractive index layer of the present invention. 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.

  Examples of the method for preparing the titanium dioxide sol that can be used in the present invention include JP-A 63-17221, JP-A 7-819, JP-A 9-165218, and JP-A 11-43327. Can be a reference.

  As other methods for preparing titanium dioxide sol, refer to, for example, JP-A-63-17221, JP-A-7-819, JP-A-9-165218, JP-A-11-43327, and the like. be able to.

  The preferable primary particle diameter of the titanium dioxide fine particles is 5 nm to 15 nm, more preferably 6 nm to 10 nm.

  Examples of the binder (resin) for the high refractive index layer in the present invention include hydrophilic resins. Examples of the hydrophilic resin include water-soluble resins, water-dispersible resins, colloid-dispersed resins, and mixtures thereof. Specific examples of the hydrophilic resin include acrylic resins, polyester resins, polyamide resins, polyurethane resins, fluorine resins and the like. For example, polyvinyl alcohol, gelatin, polyethylene oxide, polyvinyl pyrrolidone, casein, starch, agar, carrageenan And polymers such as polyacrylic acid, polymethacrylic acid, polyacrylamide, polymethacrylamide, polystyrene sulfonic acid, cellulose, hydroxylethylcellulose, carboxylmethylcellulose, hydroxylethylcellulose, dextran, dextrin, pullulan, and water-soluble polyvinylbutyral. Of these, polyvinyl alcohol is preferred. As the polymer used as the binder resin, one kind may be used alone, or two or more kinds may be mixed and used as necessary.

  The molecular weight of the polymer used as the binder resin for the high refractive index layer is not particularly limited, but polybilyl alcohol obtained by hydrolyzing vinyl acetate preferably has an average degree of polymerization of 1000 or more, particularly 1500. Those having ˜5000 are preferably used. Further, the saponification degree is preferably 70 to 100%, particularly preferably 80 to 99.5%.

  When a water-soluble resin is used, a mixture containing water as a main component and optionally a hydrophilic organic solvent may be used as a solvent. Examples of the hydrophilic solvent include alcohols such as methanol, ethanol, 2-propanol, and 1-butanol, esters such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and diethyl ether. , Ethers such as propylene glycol monomethyl ether and ethylene glycol monoethyl ether, amides such as dimethylformamide and N-methylpyrrolidone, ketones such as acetone, methyl ethyl ketone, acetylacetone and cyclohexanone, and aromatic carbonization such as benzene, toluene and xylene Examples include aliphatic hydrocarbons such as hydrogen, heptane, hexane, pentane, decane, and cyclohexane, and one or more of these are used. Rukoto can. From the environmental viewpoint, it is particularly preferable to use water or alcohols as the solvent for the coating solution.

  In order to improve the dispersion and reflection characteristics of the inorganic fine particles, a surfactant and a dispersant may be used. Examples of the surfactant include anionic, nonionic, cationic and amphoteric surfactants. Any surfactant may be used, but an anionic or nonionic surfactant is used. Is preferred. Examples of anionic surfactants include fatty acid salts, alkyl sulfate esters, alkylbenzene sulfonates, alkyl naphthalene sulfonates, dialkyl sulfosuccinates, alkyl diaryl ether disulfonates, alkyl phosphates, and polyoxyethylene alkyls. Examples thereof include ether sulfate, polyoxyethylene alkylaryl ether sulfate, naphthalene sulfonic acid formalin condensate, polyoxyethylene alkyl phosphate ester salt, glycerol borate fatty acid ester, polyoxyethylene glycerol fatty acid ester and the like.

  Nonionic surfactants include, for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, polyoxyethylene oxypropylene block copolymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin Examples include fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene alkylamines, fluorine-based resins, and silicon-based materials.

  The low refractive index layer in the present invention is preferably formed from inorganic fine particles and a small amount of a hydrophilic binder. Examples of the inorganic fine particles that can be used in the low refractive index layer of the present invention include the inorganic particles mentioned in the high refractive index layer. From the viewpoint of improving dispersibility and stability in the case of using the inorganic particle dispersion described later for inclusion in the low refractive index layer, these inorganic particles are either surface-treated or are subjected to surface treatment. You can decide whether to use something that is not there. As a specific material for the surface treatment when the surface treatment is performed, a so-called inorganic polymer such as PAC is preferable.

  When the inorganic fine particles are surface-coated with these materials, the coating amount (generally, the coating amount is indicated by the mass ratio of the surface treatment material used on the surface of the fine particles to the mass of the fine particles). Is preferably 0.01 to 99% by mass. If the coating amount is too small or too large, the effect of improving the dispersibility and stability by the surface treatment cannot be obtained sufficiently, which is not preferable.

  In the low refractive index layer according to the present invention, silica particles (silicon dioxide) are preferably used as the inorganic fine particles, and acidic colloidal silica sol is particularly preferably used.

  The metal oxide according to the present invention preferably has an average particle size of 100 nm or less. The average particle diameter (particle diameter in the dispersion state before coating) of the metal oxide dispersed in the primary particle state is preferably 20 nm or less, more preferably 10 nm or less. In addition, the average particle size of the secondary particles is preferably 30 nm or less from the viewpoint of low haze and excellent visible light transmittance.

  The average particle size of the various fine particles according to the present invention is determined simply by observing the particle itself or particles appearing on the cross section or surface of the refractive index layer with an electron microscope, measuring the particle size of 1,000 arbitrary particles, It is obtained as an average value (number average). Here, the particle diameter of each particle is represented by a diameter assuming a circle equal to the projected area.

[Inorganic polymer]
In each refractive index layer according to the present invention, an inorganic polymer such as a zirconium atom-containing compound or an aluminum atom-containing compound can be used.

  The compound containing a zirconium atom applicable to the present invention excludes zirconium oxide, and specific examples thereof include zirconium difluoride, zirconium trifluoride, zirconium tetrafluoride, hexafluorozirconium salt (for example, Potassium salt), heptafluorozirconate (for example, sodium salt, potassium salt or ammonium salt), octafluorozirconate (for example, lithium salt), fluorinated zirconium oxide, zirconium dichloride, zirconium trichloride, tetrachloride Zirconium, hexachlorozirconium salt (for example, sodium salt and potassium salt), zirconium oxychloride (zirconyl chloride), zirconium dibromide, zirconium tribromide, zirconium tetrabromide, zirconium bromide oxide, zirconium triiodide, four Diiodide Konium, zirconium peroxide, zirconium hydroxide, zirconium sulfide, zirconium sulfate, zirconium p-toluenesulfonate, zirconyl sulfate, sodium zirconyl sulfate, acidic zirconyl sulfate trihydrate, potassium zirconium sulfate, zirconium selenate, zirconium nitrate, nitric acid Zirconyl, zirconium phosphate, zirconyl carbonate, zirconyl ammonium carbonate, zirconium acetate, zirconyl acetate, zirconyl ammonium acetate, zirconyl lactate, zirconyl citrate, zirconyl stearate, zirconyl phosphate, zirconium oxalate, zirconium isopropylate, zirconium butyrate, Zirconium acetylacetonate, acetylacetone zirconium butyrate, zirconium stearate butyrate, Benzalkonium acetate, bis (acetylacetonato) dichloro zirconium and tris (acetylacetonato) chloro zirconium, and the like.

  Among these compounds, zirconyl carbonate, zirconyl ammonium carbonate, zirconyl acetate, zirconyl nitrate, zirconyl acid chloride, zirconyl lactate and zirconyl citrate are preferable, and zirconyl ammonium carbonate, zirconyl acid chloride and zirconyl acetate are particularly preferable. Specific trade names of the above compounds include zirconyl acetate ZA (trade name) manufactured by Daiichi Rare Earth Chemical Co., Ltd., zirconyl oxychloride (trade name) manufactured by Daiichi Rare Earth Chemical Co., Ltd., and the like.

  A compound containing a zirconium atom may be used alone, or two or more different compounds may be used in combination.

  Further, the compound containing an aluminum atom in the molecule that can be used in the present invention does not contain aluminum oxide. Specific examples thereof include aluminum fluoride, hexafluoroaluminic acid (for example, potassium salt), aluminum chloride, Basic aluminum chloride (eg, polyaluminum chloride), tetrachloroaluminate (eg, sodium salt), aluminum bromide, tetrabromoaluminate (eg, potassium salt), aluminum iodide, aluminate (eg, Sodium salt, potassium salt, calcium salt), aluminum chlorate, aluminum perchlorate, aluminum thiocyanate, aluminum sulfate, basic aluminum sulfate, potassium aluminum sulfate (alum), ammonium aluminum sulfate (ammonium alum) Sodium aluminum sulfate, aluminum phosphate, aluminum nitrate, aluminum hydrogen phosphate, aluminum carbonate, polysulfuric acid aluminum silicate, aluminum formate, aluminum acetate, aluminum lactate, aluminum oxalate, aluminum isopropylate, aluminum butyrate, ethyl acetate aluminum diisopropylate, aluminum Examples thereof include tris (acetylacetonate), aluminum tris (ethylacetoacetate), aluminum monoacetylacetonate bis (ethylacetoacetonate), and the like.

  Among these, aluminum chloride, basic aluminum chloride, aluminum sulfate, basic aluminum sulfate, and basic aluminum sulfate silicate are preferable, and basic aluminum chloride and basic aluminum sulfate are most preferable.

[Other additives for refractive index layer]
The high refractive index layer and the low refractive index layer according to the present invention can contain various additives as required.

  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.

[Application of near-infrared reflective film]
The near-infrared reflective film of the present invention can be applied to a wide range of fields. For example, pasting to facilities exposed to sunlight for a long time such as outdoor windows of buildings and automobile windows, film for window pasting such as heat ray reflecting film to give heat ray reflecting effect, film for agricultural greenhouse, etc. Used mainly for the purpose of improving weather resistance.

  In particular, the near-infrared reflective film according to the present invention is suitable for a member that is bonded to glass or a glass substitute resin base material 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 Co., Ltd.), ethylene-vinyl acetate copolymer (manufactured by DuPont, 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 adjusting agent etc. suitably in a contact bonding layer.

  Hereinafter, the present invention will be described specifically by way of examples. In addition, although the display of "part" or "%" is used in an Example, unless there is particular notice, it shall represent "mass part" or "mass%".

Example 1
(Sample 1—Comparative Example)
Repeatedly forming a ZrO ₂ film (thickness 135 nm) as a high refractive index layer and a SiO ₂ film (175 nm) as a low refractive index layer on a transparent polyethylene terephthalate film (PET) having a thickness of 50 μm by a known sputtering method. A near-infrared reflective film sample 1 consisting of 6 layers (12 layers in total) was prepared.

(Sample 2-Comparative Example)
Repeatedly forming a TiO ₂ film (thickness 135 nm) as a high refractive index layer and a SiO ₂ film (175 nm) as a low refractive index layer on a transparent polyethylene terephthalate film (PET) having a thickness of 50 μm by a known sputtering method. A near-infrared reflective film sample 2 consisting of 6 layers (12 layers in total) was prepared.

(Sample 3-Comparative Example)
As a high refractive index layer on a transparent polyethylene terephthalate film (PET) having a thickness of 50 μm, 100 parts of zirconia sol (Nanouse ZR30-AR, manufactured by Nissan Chemical Industries) and 20 parts of acrylic latex (TOCRYL X-4454, manufactured by Toyo Ink) are dried. It was applied with a wire bar so as to be 135 nm and dried. On top of that, colloidal silica (Snowtex OS made by Nissan Chemical Co., Ltd.) 100 parts, acrylic latex 15 parts (TOCRYL X-4454 made by Toyo Ink), an anionic fluorosurfactant (Megafuck) as a coating aid F-120) 0.4% of 4% aqueous solution was applied with a wire bar so as to be 175 nm and then dried to prepare a near-infrared reflective film sample 3 consisting of 6 layers (12 layers in total). .

(Sample 4-Comparative Example)
As a high refractive index layer on a transparent polyethylene terephthalate film (PET) PET having a thickness of 50 μm, 100 parts of rutile type titanium oxide fine particle dispersion RT-1 (as net titanium oxide), 15 parts of acrylic latex (TOCRYL manufactured by Toyo Ink) X-4454) was applied with a wire bar to a dry film thickness of 135 nm and dried. On top of that, colloidal silica (Snowtex OS manufactured by Nissan Chemical Co., Ltd.) 100 parts, acrylic latex 10 parts (TOCRYL X-4454 manufactured by Toyo Ink) as a low refractive index layer, an anionic fluorosurfactant (Megafuck) as a coating aid F-120) 0.4 part of 4% aqueous solution was applied with a wire bar so as to have a dry film thickness of 175 nm, and then repeatedly dried, and the near-infrared reflective film sample 4 consisting of 6 layers (12 layers in total). Was made.

(Sample 5-present invention)
As a high refractive index layer on a transparent polyethylene terephthalate film (PET) having a thickness of 50 μm, 100 parts of rutile-type titanium oxide fine particle dispersion RT-1) (as net titanium oxide), 12 parts of polyvinyl alcohol (PVA203 manufactured by Kuraray) Was applied with a wire bar to a dry film thickness of 135 nm. On top of that, as a low refractive index layer, 100 parts of colloidal silica (Snowtex OS manufactured by Nissan Chemical Co., Ltd.), 12 parts of polyvinyl alcohol (PVA203 manufactured by Kuraray), 4% aqueous solution of an anionic fluorosurfactant (Megafac F-120) 0.4 parts of the film was applied with a wire bar so as to have a dry film thickness of 175 nm and then repeatedly dried to prepare a near-infrared reflective film sample 5 consisting of 6 layers (12 layers in total).

(Sample 6-present invention)
Each dispersion liquid prepared above and each additive described below were sequentially mixed to prepare each coating liquid for the near-infrared reflective laminated film of the present application.

[Coating liquid for first layer low refractive index layer]
Colloidal silica (Snowtex OS, manufactured by Nissan Chemical Industries) 100 parts Polyvinyl alcohol (PVA203, manufactured by Kuraray Co., Ltd.) 12 parts The whole amount was made up to 1000 ml with pure water.

[Coating solution for second layer high refractive index layer]
Rutile-type titanium oxide fine particle dispersion (as titanium oxide) 100 parts Polyvinyl alcohol (Kuraray PVA203) 10 parts The whole amount was finished to 1000 ml with pure water.

[Coating liquid for third layer low refractive index layer]
Colloidal silica (Snowtex OS manufactured by Nissan Chemical Co., Ltd.) 100 parts Polyvinyl alcohol (PVA203 manufactured by Kuraray) 12 parts 4% aqueous solution of anionic fluorosurfactant (DIC MegaFuck F-120 manufactured by DIC)
The total amount was finished to 0.2 ml with 0.2 parts pure water.

[Fourth Layer High Refractive Index Layer Coating Liquid]
Rutile-type titanium oxide fine particle dispersion (as titanium oxide) 100 parts Polyvinyl alcohol (Kuraray PVA203) 10 parts Anionic fluorosurfactant (DIC MegaFuck F-120) 4% aqueous solution
The total amount was finished to 0.3 ml with 0.3 parts pure water.

[Formation of near-infrared reflective film]
Each of the prepared coating solutions is a slide hopper type at 40 ° C. on a transparent polyethylene terephthalate film (PET) having a thickness of 50 μm under the condition that the high refractive index layer has a dry film thickness of 135 nm and the low refractive index layer has a dry film thickness of 175 nm. Using a coater, four layers were simultaneously applied and dried, and this was repeated three times to produce a near-infrared film sample 6 consisting of 6 layers (12 layers in total).

(Sample 7-present invention)
The dispersions prepared above and the additives described below were sequentially mixed to prepare coating solutions for the near-infrared reflective multilayer film of the present application.

[Coating liquid for first layer low refractive index layer]
Colloidal silica (Snowtex OS, manufactured by Nissan Chemical Industries) 100 parts Polyvinyl alcohol (PVA203, manufactured by Kuraray Co., Ltd.) 12 parts The whole amount was made up to 1000 ml with pure water.

[Coating solution for second layer high refractive index layer]
Rutile-type titanium oxide fine particle dispersion (as titanium oxide) 100 parts Polyvinyl alcohol (Kuraray PVA203) 10 parts The whole amount was finished to 1000 ml with pure water.

[Coating liquid for third layer low refractive index layer]
Colloidal silica (Snowtex OS manufactured by Nissan Chemical Co., Ltd.) 100 parts Polyvinyl alcohol (PVA203 manufactured by Kuraray) 12 parts 4% aqueous solution of anionic fluorosurfactant (DIC MegaFuck F-120 manufactured by DIC)
The total amount was finished to 0.2 ml with 0.2 parts pure water.

[Fourth Layer High Refractive Index Layer Coating Liquid]
Rutile-type titanium oxide fine particle dispersion (as titanium oxide) 100 parts Polyvinyl alcohol (Kuraray PVA203) 10 parts Anionic fluorosurfactant (DIC MegaFuck F-120) 4% aqueous solution
The total amount was finished to 0.3 ml with 0.3 parts pure water.

[Fifth layer low refractive index layer coating solution]
Colloidal silica (Snowtex OS manufactured by Nissan Chemical Co., Ltd.) 100 parts Polyvinyl alcohol (PVA203 manufactured by Kuraray) 12 parts 4% aqueous solution of anionic fluorosurfactant (DIC MegaFuck F-120 manufactured by DIC)
The total amount was finished to 0.4 ml with 0.4 parts pure water.

[Sixth Layer High Refractive Index Layer Coating Liquid]
Rutile type titanium oxide fine particle dispersion (as titanium oxide) 100 parts Polyvinyl alcohol (Kuraray PVA203) 8 parts Anionic fluorosurfactant (DIC MegaFuck F-120) 4% aqueous solution
The total amount was finished to 0.5 ml with 0.5 parts pure water.

[Formation of near-infrared reflective film]
Each of the prepared coating solutions is a slide hopper type at 40 ° C. on a transparent polyethylene terephthalate film (PET) having a thickness of 50 μm under the condition that the high refractive index layer has a dry film thickness of 135 nm and the low refractive index layer has a dry film thickness of 175 nm. By applying a 6 layer simultaneous multilayer coating using a coater and drying, this was repeated twice to prepare a near-infrared film sample 7 consisting of 6 layers (12 layers in total).

(Sample 8-the present invention)
Each dispersion liquid prepared above and each additive described below were sequentially mixed to prepare each coating liquid for the near-infrared reflective laminated film of the present application.

[Coating liquid for first layer low refractive index layer]
Colloidal silica (Snowtex OS manufactured by Nissan Chemical Co., Ltd.) 100 parts Polyvinyl alcohol (PVA203 manufactured by Kuraray Co., Ltd.) 12 parts Boric acid 0.3 part The total amount was finished to 1000 ml with pure water.

[Coating solution for second layer high refractive index layer]
Rutile-type titanium oxide fine particle dispersion (as titanium oxide) 100 parts Polyvinyl alcohol (Kuraray PVA203) 8 parts Boric acid 0.2 parts The whole amount was finished to 1000 ml with pure water.

[Coating liquid for third layer low refractive index layer]
Colloidal silica (Snowtex OS manufactured by Nissan Chemical Co., Ltd.) 100 parts Polyvinyl alcohol (PVA203 manufactured by Kuraray) 12 parts 4% aqueous solution of anionic fluorosurfactant (DIC MegaFuck F-120 manufactured by DIC)
0.2 part Boric acid 0.3 part The whole amount was finished to 1000 ml with pure water.

[Fourth Layer High Refractive Index Layer Coating Liquid]
Rutile type titanium oxide fine particle dispersion (as titanium oxide) 100 parts Polyvinyl alcohol (Kuraray PVA203) 8 parts Anionic fluorosurfactant (DIC MegaFuck F-120) 4% aqueous solution
0.3 part Boric acid 0.2 part The whole amount was finished to 1000 ml with pure water.

[Fifth layer low refractive index layer coating solution]
Colloidal silica (Snowtex OS manufactured by Nissan Chemical Co., Ltd.) 100 parts Polyvinyl alcohol (PVA203 manufactured by Kuraray) 12 parts 4% aqueous solution of anionic fluorosurfactant (DIC MegaFuck F-120 manufactured by DIC)
0.4 part Boric acid 0.3 part The whole amount was finished to 1000 ml with pure water.

[Sixth Layer High Refractive Index Layer Coating Liquid]
Rutile type titanium oxide fine particle dispersion (as titanium oxide) 100 parts Polyvinyl alcohol (Kuraray PVA203) 8 parts Anionic fluorosurfactant (DIC MegaFuck F-120) 4% aqueous solution
0.5 part Boric acid 0.4 part The whole amount was finished to 1000 ml with pure water.

[Formation of near-infrared reflective film]
Each of the prepared coating solutions is a slide hopper type at 40 ° C. on a transparent polyethylene terephthalate film (PET) having a thickness of 50 μm under the condition that the high refractive index layer has a dry film thickness of 135 nm and the low refractive index layer has a dry film thickness of 175 nm. Six layers were simultaneously applied using a coater, and this was repeated twice to produce a near infrared film sample 8 consisting of 6 layers (12 layers in total).

(Sample 9-present invention)
In the preparation of the sample 8, in the same manner as the sample 8, except that 100 parts of the rutile-type titanium oxide fine particle dispersion of each high refractive index layer coating liquid was replaced with 100 parts of zirconia sol (Nanouse ZR30-AR manufactured by Nissan Chemical Industries). A near-infrared film sample 9 consisting of a total of 12 layers was produced.

(Sample 10-present invention)
In the preparation of Sample 8, the second simultaneous multilayer coating was added to the first to sixth layer coating solutions, and the following low refractive index layer coating solution was used for the 13th layer.

[13th layer low refractive index layer coating solution]
Colloidal silica (Snowtex OS manufactured by Nissan Chemical Co., Ltd.) 100 parts Polyvinyl alcohol (PVA203 manufactured by Kuraray) 12 parts 4% aqueous solution of anionic fluorosurfactant (DIC MegaFuck F-120 manufactured by DIC)
0.4 part Boric acid 0.5 part The whole amount was finished to 1000 ml with pure water.

  First, the near-infrared layer consisting of 7 low refractive index layers and 6 high refractive index layers (13 layers in total) in the same manner as Sample 8, except that 6 layers were simultaneously applied and then 7 layers were simultaneously applied. A reflective film sample 10 was produced.

(Sample 11-present invention)
In the preparation of Sample 8, 12 parts of polyvinyl alcohol (Kuraray PVA203) in each coating solution for low refractive index layer is 5 parts, and 10 parts of polyvinyl alcohol (Kuraray PVA203) in each coating solution for low refractive index layer is 3 parts. A near-infrared reflective film sample 11 consisting of 6 low refractive index layers and 6 high refractive index layers (12 layers in total) was prepared in the same manner as in Sample 8, except that the part was changed to the part.

(Sample 12-present invention)
In the preparation of Sample 8, 20 parts of polyvinyl alcohol (Kuraray PVA203) 12 parts of each low refractive index layer coating solution and 18 parts of polyvinyl alcohol (Kuraray PVA203) 10 parts of each low refractive index layer coating liquid. A near-infrared reflective film sample 12 consisting of 6 low refractive index layers and 6 high refractive index layers (12 layers in total) was prepared in the same manner as Sample 8 except that the part was changed to the part.

(Sample 13-Comparative Example)
In the preparation of Sample 8, 12 parts of polyvinyl alcohol (Kuraray PVA203) in each low refractive index coating solution is 22 parts, and 10 parts of polyvinyl alcohol (Kuraray PVA203) in each low refractive index coating liquid is 20 parts. A near-infrared reflective film sample 13 consisting of 6 low refractive index layers and 6 high refractive index layers (12 layers in total) was prepared in the same manner as in Sample 8 except that the part was changed to the part.

(Sample 14-present invention)
In the preparation of the sample 8, except that the second simultaneous multilayer coating was changed to the opposite side of the first simultaneous multilayer coating of the transparent polyethylene terephthalate film (PET), the same as the sample 8, A near-infrared reflective film sample 14 comprising 6 low refractive index layers and 6 high refractive index layers (12 layers in total) was produced.

(Sample evaluation)
The first high refractive index layer and the second low refractive index layer of Samples 1 to 5 obtained, and the first low refractive index layer and the second high refractive index layer of Samples 6 to 14 were separately thick. A single layer sample having the same composition was prepared on a transparent polyethylene terephthalate film (PET) having a thickness of 50 μm, and the refractive index was measured. About samples 1-14, the spectral reflection spectrum was measured and it confirmed that it had reflection in the near infrared region of 1200 nm vicinity. The laminated sample was subjected to a JIS K5600-5-1 bending resistance test.

[Measurement of refractive index of single film]
A value for a wavelength of 589 nm (Na D line) was measured with an optical thin film analyzer such as a spectroscopic ellipsometer (for example, JOVIN YVON).

(Spectral transmission spectrum measurement)
The region of 300 nm to 1400 nm was measured with a commercially available spectrophotometer (for example, U-3000 manufactured by Hitachi).

[Spectral reflection spectrum measurement]
The region of 300 nm to 2000 nm was measured with a commercially available spectrophotometer (using an integrating sphere, for example, U-4000 manufactured by Hitachi). At this time, measurement was performed 20 times while changing the position of the sample in the optical path, and the average value was taken as the measured value of the near infrared reflectance. The coefficient of variation (standard deviation / average value) was calculated. A larger coefficient of variation indicates that the film surface is more uneven, and if it exceeds 3.0%, it can be said that there is a problem in product quality.

[JIS K5600-5-1 Bend resistance test (mandrel method)]
Based on JIS K5600-5-1 bending resistance test, using a bending test at 25 ° C. using a bending tester type 1 (manufactured by Imoto Seisakusho: high-rigidity specification capable of measuring from 15 mm to 50 mm in mandrel diameter). Flexibility evaluation was performed. The sample has a size of 100 mm × 50 mm, and a bending test is performed by using a mandrel having a diameter of 15 mm, 20 mm, 25 mm, 30 mm, 40 mm, and 50 mm and folding the near infrared reflective laminated film with the near infrared laminated film side outward. Thereafter, the diameter of the mandrel which was observed by visual observation and started to cause the near-infrared reflective laminate film to crack or peel from the transparent support was recorded.

[Defect evaluation of laminated glass]
The obtained near-infrared film samples 1 to 14 were each sandwiched between two PVB films having a thickness of 0.38 mm, and further curved (radius of curvature) having a size of 250 mm × 350 mm and a thickness of 2 mm. A minimum value of 0.9 m and a maximum value of 1 m) Two glass plates having the same shape were used to produce a laminated glass as follows.

  The curved glass plate is produced by bending float glass. The minimum value of the radius of curvature of 0.9 m is a value near the periphery of the glass plate, and the maximum value of the radius of curvature of 1 m is glass. This is the value at the center of the plate.

  Glass plate, PVB film, near-infrared film samples 1 to 14, PVB film, and glass plate were sequentially stacked, and PVB film protruding from the edge of the glass plate and excess portions of the near-infrared film sample were cut and removed. Then, it combined and processed by pressure deaeration for 30 minutes in the autoclave heated at 150 degreeC.

  The number of cracks or wrinkles in the produced near-infrared reflective laminated glass was visually counted, and the results were recorded.

  The results of the above measurements and evaluations for samples 1 to 14 are summarized in Table 1.

  As is apparent from the results in Table 1, the near-infrared film sample of the present invention has good transparency in the visible light region, and also has a reflection performance in the near-infrared region and flexibility that does not cause wrinkles and cracks. You can see that

Claims (8)

  Near red formed by laminating two units of adjacent layers having different refractive indexes in the wavelength range of 750 to 1400 nm on the transparent support and having a difference in refractive index of both layers of 0.3 or more. A near-infrared reflective film having an outer reflective laminated film, wherein the near-infrared reflective film is subjected to a bending resistance test (cylindrical mandrel method) described in JIS K5600-5-1. However, the diameter of the mandrel that begins to crack or peel off from the transparent support is 30 mm or less.   The near-infrared reflective film according to claim 1, wherein the near-infrared reflective laminated film is formed by a unit laminated by simultaneous multilayer coating.   The near-infrared reflective film according to claim 1 or 2, wherein the near-infrared reflective laminated film is formed of two or more units laminated by simultaneous multilayer coating.   The infrared reflection film according to any one of claims 1 to 3, wherein the near-infrared reflection laminated film is formed of three or more units laminated by simultaneous multilayer coating.   The near-infrared reflective laminated film contains at least one selected from metal oxides or inorganic fine particles and polyvinyl alcohol in at least one layer of a unit forming the near-infrared reflective laminated film, and includes at least two or more The near-infrared reflective film according to claim 1, wherein the near-infrared reflective film is formed by laminating units.   The near-infrared reflective laminated film has an average particle size as a metal oxide in a layer having a higher refractive index in the wavelength range of 750 to 1400 nm of the unit forming the near-infrared reflective laminated film than other layers. The near-infrared reflective film according to claim 1, comprising titanium oxide particles having a diameter of 100 nm or less and polyvinyl alcohol.   The near-infrared reflective laminated film has an average particle size as inorganic fine particles in a layer having a lower refractive index in the wavelength range of 750 to 1400 nm than the other layers of the unit forming the near-infrared reflective laminated film The near-infrared reflective film according to claim 1, comprising silica particles of 100 nm or less and polyvinyl alcohol.   A near-infrared reflector, wherein the near-infrared reflective film according to any one of claims 1 to 7 is provided on at least one surface of a substrate.