JP6642235B2 - Optical reflection film and method for manufacturing optical reflection film - Google Patents

Description

  The present invention relates to an optical reflection film and a method for manufacturing an optical reflection film.

  In general, it is known that a multilayer film in which a low-refractive-index layer and a high-refractive-index layer are respectively laminated on the surface of a substrate by adjusting the optical film thickness selectively reflects light of a specific wavelength. ing. Such a multilayer film is used, for example, as an optical reflection film installed on a window of a building or a member for a vehicle. Such an optical reflection film can control the reflection wavelength only by adjusting the thickness and refractive index of each layer, and can reflect various lights such as infrared rays, ultraviolet rays, and visible lights.

  In recent years, interest in energy conservation measures has increased, and insulated glass with infrared shielding properties for the purpose of shielding solar radiation energy entering the room or inside the vehicle, reducing the temperature rise and cooling load in architectural glass and vehicle glass Has been adopted. On the other hand, conventionally, an infrared shielding film formed by laminating layers having different refractive indexes is known, and a method of blocking transmission of heat rays in sunlight by attaching the infrared shielding film to glass. However, attention is being paid as a simpler method.

  As the infrared shielding film, there is a method in which a laminated film in which low-refractive-index layers and high-refractive-index layers are alternately laminated is produced by a vapor deposition method such as an evaporation method or a sputtering method. However, the vapor deposition method has problems such as high production cost, difficulty in increasing the area, and limitation to heat-resistant materials.

  In view of such a problem, the manufacturing cost is low, the area can be increased, and the selection range of the base material is wide. ) Has been proposed. As a technique using such a liquid phase film forming method, Patent Document 1 discloses a high refractive index layer containing metal oxide particles such as titania and a water-soluble polymer, and an oxide particle such as silica and a water-soluble A technique for laminating a low refractive index layer containing molecules by simultaneous multi-layer coating is disclosed.

  As a technique using the liquid phase film forming method as described above, Patent Literature 2 discloses a technique in which an inorganic polymer (cationic polymer) is added to the high refractive index layer or the low refractive index layer as described above. ing.

JP 2012-252148 A JP 2012-27288 A

  However, in recent years, an optical reflection film having a higher level of optical characteristics has been demanded, and further improvement in optical characteristics has been demanded. As one of the techniques for satisfying such demands, there is a demand for a technique capable of not only reducing haze but also suppressing coating unevenness.

  Therefore, an object of the present invention has been made in view of the above circumstances, and it is an object of the present invention to provide means for effectively reducing haze and suppressing coating unevenness in an optical reflection film.

  The present inventor has conducted intensive studies in view of the above problems. As a result, in an optical reflection film including at least one unit in which a low-refractive-index layer and a high-refractive-index layer are laminated, the above-described problem is solved by forming a low-refractive-index layer having the following configuration. And completed the present invention.

  That is, the above object is an optical reflection film including at least one unit in which a low refractive index layer and a high refractive index layer are laminated on a substrate, wherein the low refractive index layer is a water-soluble polymer, This is achieved by an optical reflection film containing silicon oxide particles, a cationic polymer, and an amino alcohol containing no carboxyl group.

  According to the present invention, in the optical reflection film, the low-refractive-index layer contains a specific amino alcohol together with a water-soluble polymer, silicon oxide particles and a cationic polymer, thereby effectively reducing haze and coating. A technique capable of suppressing unevenness is provided.

  According to one embodiment of the present invention, there is provided an optical reflection film including at least one unit in which a low-refractive-index layer and a high-refractive-index layer are laminated on a substrate, wherein the low-refractive-index layer has a water-soluble high refractive index layer. An optical reflection film is provided that contains a molecule, silicon oxide particles, a cationic polymer, and an amino alcohol without a carboxyl group. The optical reflection film having such a configuration exhibits good optical characteristics because not only haze but also coating unevenness is effectively reduced.

  The low-refractive-index layer is formed by a liquid-phase film-forming method by preparing a coating solution containing a material such as a water-soluble polymer or silicon oxide particles (hereinafter, also referred to as a “low-refractive-index layer coating solution”), Is applied so as to be alternately laminated with the coating solution for the high refractive index layer, and dried. This drying is generally performed while blowing dry air (warm air or the like). Here, in the course of the study, the present inventor applied a low-refractive-index layer coating solution further containing a cationic polymer in addition to the water-soluble polymer and silicon oxide particles on a substrate, and then dried the substrate. It has been found that the coating liquid applied on the material may be swept away by the drying air to cause coating unevenness (drying unevenness).

  The present inventors have conducted intensive studies in order to suppress such coating unevenness, and surprisingly, by adding an amino alcohol that does not contain a carboxyl group, a haze reducing effect and a coating unevenness suppressing effect are obtained. Was found to be. The mechanism by which such an effect is obtained is not clear, but is presumed as follows.

  In a low refractive index layer coating solution containing a water-soluble polymer and silicon oxide particles, when a cationic polymer is not contained, a hydroxyl group present on the surface of the silicon oxide particles and a water-soluble polymer (more specifically, a hydroxyl group) (A hydrophilic group such as a group) physically and / or chemically interact to form a network structure. Thus, it is presumed that the low-refractive-index layer coating liquid easily maintains an appropriate viscosity, and coating unevenness hardly occurs. On the other hand, when the coating solution for the low refractive index layer further contains a cationic polymer, the polymer is adsorbed on the surface of the silicon oxide particles, thereby inhibiting the interaction between the water-soluble polymer and the surface of the silicon oxide particles. It is considered that such a network structure is unlikely to be formed, and as a result, the viscosity of the coating solution for the low refractive index layer tends to decrease. Therefore, it is swept away by the drying air as described above, and coating unevenness easily occurs.

  On the other hand, when an amino alcohol is added as in the present invention, it becomes possible for the amino group of the amino alcohol to interact with the surface of the silicon oxide particles so as to enter the gap of the cationic polymer, and Interact with the water-soluble polymer. Thus, the amino alcohol is considered to play a role as a crosslinking agent between the water-soluble polymer and the silicon oxide particles. As a result, it is easy to form a network structure using the water-soluble polymer and the silicon oxide particles, and it is possible to suppress a decrease in viscosity even with a low refractive index layer coating solution containing a cationic polymer. Therefore, it is considered that coating unevenness is effectively suppressed.

  Furthermore, in the present invention, an amino alcohol that does not contain a carboxyl group is used. By adopting such a compound, aggregation and crystallization in the coating solution for the low refractive index layer or partial reaction with the water-soluble polymer can be suppressed, and the haze is reduced to meet stricter standards. Can be achieved.

  Further, since the silicon oxide particles contained in the low refractive index layer are anionic, the coexisting cationic polymer is easily adsorbed to the silicon oxide particles. As a result, it is considered that the zeta potential of the silicon oxide particles becomes positive and the surface of the silicon oxide particles becomes cationic.

  Here, it is desirable that the high-refractive-index layer constituting the optical reflection film together with the low-refractive-index layer contains a material for expressing a high refractive index, but these materials are generally cationic materials. (For example, titania and zirconia as disclosed in Patent Document 1 and Patent Document 2). Therefore, interfacial mixing between the low-refractive index layer and the high-refractive index layer is suppressed by the electrical repulsion between the low-refractive index layer to which the cationic polymer is added and the high-refractive index layer as described above. Therefore, it is assumed that the reaction and suspension at the interface are suppressed, and the haze of the optical reflection film is further reduced.

  Note that the mechanism of exhibiting the function and effect of the configuration of the present invention described above is speculation, and the present invention is not limited to the above speculation.

  Hereinafter, components of the optical reflection film of the present invention will be described in detail. In this specification, “X to Y” indicating a range includes X and Y, and means “X or more and Y or less”. Unless otherwise specified, the operation, physical properties, and the like are measured under conditions of room temperature (20 to 25 ° C.) / Relative humidity of 40 to 50% RH.

(Optical reflection film)
The optical reflection film according to the present invention includes at least one unit in which a low refractive index layer and a high refractive index layer are laminated on a substrate. In this specification, the terms “low-refractive-index layer” and “high-refractive-index layer” refer to a lower refractive index layer having a lower refractive index when comparing the refractive index difference between two adjacent layers. Means that the higher refractive index layer is a high refractive index layer. In the present invention, since the “low refractive index layer” contains silicon oxide particles (silica particles), the refractive index layer adjacent thereto is designed to have a higher refractive index than the “low refractive index layer”. This results in a “high refractive index layer”.

  Further, in the present specification, when the low refractive index layer and the high refractive index layer are not distinguished from each other, a concept including both of them may be referred to as a “refractive index layer”. Further, in this specification, a portion in which a plurality of units in which a low refractive index layer and a high refractive index layer are stacked may be simply referred to as an “optical reflection layer” or a “reflection layer”.

  The optical reflection film preferably has a substrate and an optical reflection layer in this order, and the optical reflection layer is preferably arranged on a surface on which light is incident. Further, the optical reflection layer may be arranged adjacent to the base material, or another layer may be interposed between the base material and the optical reflection layer.

≪Low refractive index layer≫
The optical reflection film of the present invention comprises, in the low refractive index layer constituting the optical reflection layer, an amino alcohol having no carboxyl group, a cationic polymer, silicon oxide particles, and a water-soluble polymer. Hereinafter, first, each component included in the low refractive index layer will be described in detail. The carboxyl-free amino alcohol, cationic polymer, silicon oxide particles, and water-soluble polymer may be contained in at least one of a plurality of low refractive index layers.

<Amino alcohol containing no carboxyl group>
In the optical reflection film according to the present invention, the low refractive index layer contains an amino alcohol that does not contain a carboxyl group (in this specification, it may be simply referred to as “amino alcohol”). The amino alcohol used in the present invention has both one or more amino groups and one or more hydroxyl groups (-OH) in the molecule and does not contain a carboxyl group (-COOH). In addition, the amino group in the present invention shall include structures such as a secondary amine and a tertiary amine in addition to a general amino group (—NH ₂ ) belonging to a primary amine. In addition, the amino group of the amino alcohol may be present in the low refractive index layer in the form of -NH ₃ ⁺ to which a proton is coordinated. In one low refractive index layer, one kind of amino alcohol may be used alone, or two or more kinds may be used in combination.

  As described above, the amino alcohol according to the present invention interacts (adsorbs) with the surface of the silicon oxide particles contained in the low-refractive-index layer by an amino group, and has a water-soluble property contained in the low-refractive-index layer. Interacts with macromolecules via hydroxyl groups. Therefore, the water-soluble polymer and the silicon oxide particles can interact with each other via the amino alcohol, and these easily form a network structure. In other words, the amino alcohol according to the present invention plays a role in promoting the interaction between the water-soluble polymer and the silicon oxide particles. As a result, a decrease in the viscosity of the coating solution for the low refractive index layer is suppressed, and uneven coating can be effectively suppressed.

  Further, since the amino alcohol according to the present invention does not contain a carboxyl group, aggregation and crystallization of the amino alcohol itself can also be suppressed, thereby effectively reducing haze.

  The content of the amino alcohol (when two or more amino alcohols are included, the total amount thereof) in the low refractive index layer is not particularly limited, but it is easy to form a network structure between the silicon oxide particles and the water-soluble polymer. However, for the purpose of imparting an appropriate viscosity to the coating solution for the low refractive index layer, the content is preferably within the following range. That is, the content of the amino alcohol in the low refractive index layer is 0.01 to 5% by mass based on the total amount of the silicon oxide particles (when a plurality of types of silicon oxide particles are included, the total mass thereof). And more preferably 0.05 to 2% by mass, and particularly preferably more than 0.05% by mass and less than 2.0% by mass. When a plurality of types of amino alcohols are contained, the total amount is preferably within the above range. When the content is 0.01% by mass or more, the effect of forming the network structure can be sufficiently obtained. As described above, the amino alcohol according to the present invention can provide a sufficient coating unevenness suppressing effect even in a very small amount. When the content is 5% by mass or less, the increase in haze due to the addition of amino alcohol does not pose a problem, and from such a viewpoint, it contributes to the suppression of haze.

Here, the content (M _A : mass) of the amino alcohol and the content (M _SiO2 : mass) of the _silicon oxide particles in the low refractive index layer are measured by performing the following analysis on the low refractive index layer. Is done.

First, the content (mole number) of amino alcohol in the low refractive index layer can be measured by analyzing the optical reflection film using FT-IR (Fourier transform infrared spectroscopy). Then, the mass (M _A ) of the amino alcohol contained in the low refractive index layer is calculated from the obtained number of moles of the amino alcohol based on the molecular weight of the amino alcohol obtained in advance. The measurement at this time is preferably performed after drying at a temperature lower than the melting temperature of the base material for 1 to 60 minutes in order to reduce the influence of the absorption of water molecules. In addition, the molecular weight of the amino alcohol can be measured by mass spectrometry using an electron ionization method.

Next, the content of silicon oxide particles in the low-refractive-index layer was determined by a method (STEM-EDX) combining scanning transmission electron microscope and energy dispersive X-ray spectroscopy. From the obtained and obtained results, the mass (M _SiO2 ) of the _silicon oxide particles can be obtained.

  The amino alcohol used in the present invention is not particularly limited, and any amino alcohol that can promote the interaction between the water-soluble polymer and the silicon oxide particles as described above may be used. For example, primary amines such as monoethanolamine, neopentanolamine, 2-aminopropanol, 2-amino-2-methyl-1-propanol, 3-aminopropanol and tris (hydroxymethyl) aminomethane; diethanolamine, diethanolamine Secondary amines such as n-propanolamine, diisopropanolamine, N-methylethanolamine, N-ethylethanolamine and 3,4-pyrrolidinediol; triethanolamine, dimethylethanolamine, dibutylethanolamine, methyldiethanolamine, Ethyl diethanolamine, triisopropanolamine, 1-piperidine-1-propanol, N-ethyl-3,4-piperidinediol, N-ethyl-3,5-piperidinediol, N- (2-hydroxypropanol) Tertiary amines Le) -3,5-piperidine-diol and the like; and the like can be used. These amino alcohols may be used alone or in a combination of two or more.

  Amino alcohols are divalent from the viewpoint that they can more easily interact with water-soluble polymers, easily form a network structure with water-soluble polymers, and can easily suppress a decrease in viscosity of the coating solution for the low refractive index layer. It is preferably an alcohol or a trihydric alcohol. That is, the amino alcohol preferably contains two or three hydroxyl groups. These amino alcohols have more hydroxyl groups serving as cross-linking points than monohydric alcohols, so that the above-mentioned effects are easily obtained. In order to obtain such an effect, alcohols having a valency of 4 or more may be used. The production cost of the reflective film can be reduced.

  The amino alcohol contained in the low refractive index layer may be any of primary to tertiary amines as described above, and among them, primary amines are preferred. That is, the amino alcohol preferably has a primary amino group. The primary amino group has less steric hindrance around the nitrogen atom than the secondary and tertiary amino groups, and thus easily enters the gap of the cationic polymer adsorbed on the surface of the silicon oxide particles. Therefore, the interaction between the amino alcohol and the silicon oxide particles is facilitated, and the interaction between the silicon oxide particles and the water-soluble polymer is facilitated via the amino alcohol. As a result, these can easily form a network structure, and a decrease in the viscosity of the low refractive index layer coating solution can be suppressed.

  From the above, the amino alcohol is more preferably a dihydric alcohol or a trihydric alcohol and having a primary amino group, more preferably a trihydric alcohol and having a primary amino group. It is particularly preferred that there is. Such an amino alcohol can more easily form a network structure between the silicon oxide particles and the water-soluble polymer, so that the viscosity of the coating solution for the low refractive index layer can be more easily suppressed from decreasing.

  Furthermore, the number of carbon atoms of the amino alcohol is not particularly limited, but is preferably 12 or less, more preferably 1 to 10, from the viewpoint that steric hindrance is small and interaction with the surface of the silicon oxide particles is easy. It is more preferably from 2 to 8, and particularly preferably from 2 to 6. Further, if the content is within the above range, it is also preferable that deterioration of haze caused by addition of amino alcohol does not pose a problem.

  Further, as shown by the compounds exemplified above, the amino alcohol may be linear, branched, or cyclic. Among them, from the viewpoint of reducing the steric hindrance on the surface of the silicon oxide particles and promoting the interaction between the amino alcohol and the surface of the silicon oxide particles, the amino alcohol is preferably linear or branched. .

  Therefore, from the above, as the amino alcohol contained in the low refractive index layer, considering the effects obtained and the availability, the monoethanolamine, diethanolamine, N-ethylethanolamine, triethanolamine and tris (hydroxymethyl A) preferably selected from the group consisting of aminomethane, more preferably selected from the group consisting of monoethanolamine, diethanolamine, triethanolamine and tris (hydroxymethyl) aminomethane, more preferably tris (hydroxymethyl) aminomethane Is particularly preferred.

<Cationic polymer>
In the optical reflection film according to the present invention, the low refractive index layer contains a cationic polymer together with a water-soluble polymer, silicon oxide particles and the above-mentioned amino alcohol. The cationic polymer is adsorbed on the surface of the silicon oxide particles that are anionic, acts to make the zeta potential of the silicon oxide particles positive, and imparts cationicity. As a result, interfacial mixing with the high refractive index layer described in detail below is suppressed, and haze can be reduced. Note that, like the low refractive index layer, the high refractive index layer preferably contains a cationic polymer. In this case, the cationic polymer contained in the high and low refractive index layers may be the same as or different from the resin contained in the low refractive index layer.

  In the present specification, the cationic polymer means a polymer having a cationic or cationic group. Further, “cationic group” refers to a group that is converted to a cation in the presence of an acid.

  The cationic polymer may be an inorganic polymer or an organic polymer.

  Examples of the inorganic polymer include an inorganic polymer composed of a metal oxide formed by subjecting a metal salt compound capable of hydrolysis and polycondensation to hydrolysis and polycondensation by a so-called sol-gel method. Among them, an inorganic polymer formed by using a compound containing a zirconium atom, a compound containing an aluminum atom, or the like and subjecting it to hydrolysis and polycondensation is preferable.

  In these inorganic polymers, OH groups generated in the course of hydrolysis remain even after the polycondensation reaction, and thus it is considered that the OH groups form a hydrogen bonding network of the OH groups, thereby improving flexibility.

  Specific examples of the inorganic polymer containing a zirconium atom include zirconyl chloride and zirconyl nitrate. Specific product names of the above compounds include Zircosol (registered trademark) ZC-2 (zirconyl chloride) manufactured by Daiichi Kagaku Kagaku Kogyo, and Zircosol (registered trademark) ZN (zirconyl nitrate) manufactured by Daiichi Kagaku Kagaku Kogyo. Is mentioned.

  Specific examples of the inorganic polymer containing an aluminum atom include basic aluminum chloride, basic aluminum sulfate, and basic aluminum sulfate silicate. Among these, basic aluminum chloride and basic aluminum sulfate are preferable. Examples of the trade name of the above compound include Takibain (registered trademark) # 1500 manufactured by Taki Kagaku Co., Ltd.

  The structural formula of Takibaine (registered trademark) # 1500 is shown below.

  Here, s, t, and u represent an integer of 1 or more.

  The above-mentioned inorganic polymers may be used alone or in a combination of two or more.

  The cationic polymer in the present invention is preferably an organic polymer. This is because organic polymers have better stretchability than inorganic polymers, so even if silicon oxide particles are highly filled to maintain the refractive index, they can easily follow the expansion and contraction of the layer due to temperature change, and crack This is because it is unlikely to occur.

  Examples of the cationic polymer which is an organic polymer include, but are not particularly limited to, vinylpyrrolidone / N, N-dimethylaminoethyl methacrylic acid copolymer diethyl sulfate, starch sugar hydroxypropyltrimethylammonium chloride ether, polyethyleneimine, polyallylamine, and polyvinylamine , Polyvinylpyridine, polyethyleneimine-epichlorohydrin reactant, polyamide-polyamine resin, polyamide-epichlorohydrin resin, chitosans, cationized starch, polyaminesulfone, polyvinylimidazole, polyamidine, dicyanamide polyalkylenepolyamine condensate, polyalkylenepolyamine dicyandiamide ammonium Salt condensate, dicyandiamide formalin condensate, diallyldimethyl ammonium chloride Ride polymer and copolymer, vinylpyrrolidone / vinylimidazole copolymer, vinylbenzyltrimethylammonium chloride polymer and copolymer, dimethylaminoethyl (meth) acrylate polymer and copolymer, (meth) acryloyloxyalkyl tri Examples thereof include alkyl ammonium chloride polymers and copolymers, and (meth) acryloyloxyalkyldialkylbenzyl ammonium chloride polymers.

  Further, for example, a cation-modified polyvinyl having a primary to tertiary amino group or quaternary ammonium group in the main chain or side chain of polyvinyl alcohol as described in JP-A-61-10483. Alcohol can also be used. The cation-modified polyvinyl alcohol 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 in the cation-modified polyvinyl alcohol is, for example, 0.1 to 10 mol%, preferably 0.2 to 5 mol%, based on vinyl acetate.

  The cationic polymer in the present invention is an organic amine polymer containing at least one selected from the group consisting of primary to tertiary amino groups and their cations (salts), and quaternary ammonium groups as cationic groups. It is preferred that there is. These polymers are relatively strongly bonded to the surface of the silicon oxide particles by the cationic group, and can make the surface of the silicon oxide particles cationic. Therefore, when the high refractive index layer contains cationic metal oxide particles, the effect of suppressing interfacial mixing between the high refractive index layer and the low refractive index layer is increased, and the effect of reducing haze can be further improved. . Especially, it is preferable that the cationic polymer contains at least one kind of cationic group selected from the group consisting of a tertiary amino group, a cation of a tertiary amino group, and a quaternary ammonium group. These cationic groups are stabilized by cations and are easily adsorbed specifically on the surface of the silicon oxide particles. Therefore, the cationicity of the low-refractive-index layer is further increased, and interface mixing is easily suppressed, so that haze can be further reduced.

  For example, as organic amine polymers, polyallylamine and its quaternized products, polyallylamine hydrochloride (PAH), polydiallyldimethylammonium chloride (PDDA), polyvinylpyridine (PVP), polylysine, polyacrylamide, polypyrrole, polyaniline, polyaniline Paraphenylene (+), polyparaphenylene vinylene, polyethyleneimine, and copolymers containing at least two or more of them and those having different kinds of salts can be used.

  More specifically, polyallylamine amide sulfate, a copolymer of allylamine hydrochloride and diallylamine hydrochloride, a copolymer of allylamine hydrochloride and dimethylallylamine hydrochloride, an allylamine hydrochloride and other copolymer, partially Methoxycarbonylated allylamine polymer, partially methylcarbonylated allylamine acetate polymer, diallylamine hydrochloride polymer, methyldiallylamine hydrochloride polymer, methyldiallylamine amide sulfate polymer, methyldiallylamine acetate polymer, diallylamine hydrochloride and carbon dioxide Sulfur copolymer, copolymer of diallylamine acetate and sulfur dioxide, copolymer of diallylmethylethylammonium ethyl sulfate and sulfur dioxide, copolymer of methyldiallylamine hydrochloride and sulfur dioxide, diallyldimethyl Copolymer of ammonium chloride and sulfur dioxide, copolymer of diallyldimethylammonium chloride and acrylamide, copolymer of diallyldimethylammonium chloride and diallylamine hydrochloride derivative, copolymer of dimethylamine and epichlorohydrin And a copolymer of dimethylamine, ethylenediamine and epichlorohydrin, and a copolymer of polyamidepolyamine and epichlorohydrin.

  The organic polymer may be used alone or in a combination of two or more.

  In the present invention, it is preferable to use two or more cationic polymers for the low refractive index layer. Compared to the case where only one kind of cationic polymer is used, it is possible to disperse the silicon oxide particles in the low-refractive-index layer without causing sedimentation while finely aggregating, and as a result, the optical reflection film with less haze Is obtained. Therefore, when two types of cationic polymers, that is, a cationic polymer having a high effect of maintaining the dispersion stability of silicon oxide particles and a cationic polymer having a high cohesiveness, are used in combination, the effect of the present invention can be more remarkably obtained. For example, as the cationic group, a cationic polymer having a primary amino group, a secondary amino group, a tertiary amino group or a cation (salt) thereof, particularly a tertiary amino group, or a cation (salt) thereof is used. The cationic polymer contained therein effectively cationizes the surface of the silicon oxide particles and contributes to maintaining the dispersion stability of the silicon oxide particles in the coating solution for the low refractive index layer. Therefore, the cationic polymer in the low refractive index layer preferably contains a cationic polymer having a tertiary amino group or a cation (salt) thereof as a cationic group. On the other hand, cationic polymers having a quaternary ammonium group, a primary amino group, a secondary amino group and a cation (salt) thereof, particularly a cationic polymer having a quaternary ammonium group as a cationic group include silicon oxide. It has the effect of causing fine aggregation of the particles and protecting the silicon oxide particles. Therefore, by further using a cationic polymer having a quaternary ammonium group, it becomes easy to cause micro-aggregation without sedimentation of the silicon oxide particles, and the effect of the present invention can be more remarkably obtained. That is, in the present invention, it is preferable to use a cationic polymer having a tertiary amino group or a cation (salt) thereof in combination with a cationic polymer having a quaternary ammonium group as the cationic polymer.

  In particular, a methyldiallylamine hydrochloride polymer, a methyldiallylamine amide sulfate polymer, a methyldiallylamine acetate polymer and the like are preferably used as a cationic polymer containing a tertiary amino group or a cation (salt) thereof, and diallyldimethylammonium chloride is used. Polymers and the like can be suitably used as the cationic polymer containing a quaternary ammonium group.

  The content of the cationic polymer is not particularly limited as long as the effects of the present invention are exerted. However, the content of the cationic polymer is preferably set to a value of the silicon oxide particles contained in the low refractive index layer (including a plurality of types of silicon oxide particles). Is preferably 0.5 to 20% by mass, more preferably 1 to 10% by mass, and particularly preferably 2 to 8% by mass. When a plurality of types of cationic polymers are included, the total is preferably within the above range. When the content of the cationic polymer is 0.5% by mass or more based on the total amount of the silicon oxide particles contained in the low refractive index layer, the effect of the present invention can be more remarkably obtained. On the other hand, when the content is 20% by mass or less, there is no deterioration in weather resistance due to the cationic polymer to the physical properties of the coating film, which is preferable.

  The weight average molecular weight of the cationic polymer is not particularly limited, but is preferably, for example, 10,000 to 100,000, more preferably 20,000 to 50,000, and 20,000 to 30,000. Is more preferable. When two or more cationic polymers are used, the weight average molecular weight of any of the two or more cationic polymers is preferably from 10,000 to 100,000, more preferably from 20,000 to 50,000. , 20,000 to 30,000. When the content is within the above range, the effects of the present invention can be obtained particularly remarkably. In the present specification, the value of the “weight average molecular weight” is a value measured by gel permeation chromatography (GPC).

<Silicon oxide particles>
In the optical reflection film of the present invention, the low refractive index layer contains silicon oxide (silicon dioxide) particles. Specific examples include synthetic amorphous silica and colloidal silica. Among these, it is more preferable to use a colloidal silica sol, particularly an acidic colloidal silica sol, and it is particularly preferable to use a colloidal silica dispersed in an organic solvent. In order to further reduce the refractive index, hollow fine particles having voids inside the particles may be used as silicon oxide particles of the low refractive index layer, and hollow fine particles of silicon oxide (silicon dioxide) are particularly preferable. As the silicon oxide particles contained in the low refractive index layer, one type may be used alone, or two or more types may be used in combination.

  The silicon oxide particles contained in the low refractive index layer preferably have an average particle size (number average; diameter) of 1 to 100 nm. The average particle size of the primary particles of silicon dioxide (primary average particle size, particle size in a dispersion before coating) is more preferably 1 to 50 nm, still more preferably 1 to 40 nm, and 3 to 3 nm. It is particularly preferably 20 nm, and most preferably 4 to 10 nm. The average particle size of the secondary particles is preferably 30 nm or less from the viewpoint of less haze and excellent visible light transmittance.

  The primary average particle diameter can be measured from an electron micrograph by a transmission electron microscope (TEM) or the like. It may be measured by a particle size distribution analyzer using a dynamic light scattering method, a static light scattering method, or the like. When determined by a transmission electron microscope, the primary average particle size of the particles is observed by an electron microscope on the particles themselves or particles that appear on the cross section or surface of the refractive index layer, and the particle size of 1,000 arbitrary particles is measured. It is obtained as its simple average value (number average). Here, the particle diameter of each particle is represented by a diameter assuming a circle equal to its projected area.

  Colloidal silica used in the present invention is obtained by heating and aging a silica sol obtained by double decomposition of sodium silicate with an acid or the like and passing through an ion exchange resin layer, for example, JP-A-57-14091, JP-A-60-219083, JP-A-60-219084, JP-A-61-20792, JP-A-61-188183, JP-A-63-17807, JP-A-4-93284. JP-A-5-278324, JP-A-6-92011, JP-A-6-183134, JP-A-6-297830, JP-A-7-81214, JP-A-7-101142 And Japanese Patent Application Laid-Open Nos. 7-179029, 7-137431, and WO 94/26530. It is.

  As such colloidal silica, a synthetic product or a commercially available product may be used. Commercially available products include Snowtex (registered trademark, the same applies hereinafter) series (Snowtex OS, OXS, S, OS, 20, 30, 40, O, N, C, etc.) sold by Nissan Chemical Industries, Ltd. No.

  Colloidal silica may have its surface cationically modified, or may have been treated with Al, Ca, Mg, Ba or the like.

  As described above, hollow fine particles can be used as the silicon oxide particles of the low refractive index layer. When hollow fine particles are used, the average particle pore diameter is preferably from 3 to 70 nm, more preferably from 5 to 50 nm, and even more preferably from 5 to 45 nm. In addition, the average particle pore diameter of the hollow fine particles is an average value of the inner diameter of the hollow fine particles. When the average particle pore diameter of the hollow fine particles is in the above range, the refractive index of the low refractive index layer is sufficiently reduced. The average particle pore diameter is obtained by observing at least 50 pore diameters that can be observed as a circle, an ellipse, or a substantially circular ellipse by electron microscopy, calculating the pore diameter of each particle, and calculating the number average value. Is obtained. In addition, the average particle pore diameter means a minimum distance among distances in which an outer edge of a pore diameter observable as a circle, an ellipse, or a substantially circle or an ellipse is sandwiched between two parallel lines.

  The content of the silicon oxide particles in the low refractive index layer is preferably 20 to 90% by mass, more preferably 30 to 85% by mass, and more preferably 40 to 90% by mass based on the total solid content of the low refractive index layer. More preferably, it is 80% by mass. When the content is 20% by mass or more, a desired refractive index is obtained, and when the content is 90% by mass or less, the coatability is improved, which is preferable. When a plurality of types of silicon oxide particles are included, the total is preferably within the above range.

<Water-soluble polymer>
In the optical reflection film of the present invention, the low refractive index layer contains a water-soluble polymer as a binder together with an amino alcohol, a cationic polymer and silicon oxide particles. Since water can be used as a solvent, the water-soluble polymer is preferable in that it does not corrode, dissolve, or penetrate into a substrate described later. Further, the water-soluble polymer is preferable because the flexibility is high and the durability of the optical reflection layer at the time of bending is improved. Further, like the low refractive index layer, the high refractive index layer preferably contains a water-soluble polymer. The water-soluble polymer contained in the low refractive index layer may be the same as or different from the water-soluble polymer contained in the high refractive index layer.

  In the present invention, examples of the water-soluble polymer include, but are not particularly limited to, synthetic water-soluble polymers such as polyvinyl alcohols and polyvinylpyrrolidones; and natural water-soluble polymers such as gelatin and thickening polysaccharides. Among these, from the viewpoint of interaction with silicon oxide particles, it is preferable that the water-soluble polymer has a hydroxyl group. Among them, polyvinyl alcohols are preferably used from the viewpoint of low oxygen permeability. In addition, when the refractive index layer further includes metal oxide particles having a photocatalytic action, the polyvinyl alcohol has an effect of suppressing the photocatalytic action. From these viewpoints, the polyvinyl alcohol is preferably contained in both the high refractive index layer and the low refractive index layer.

  The polyvinyl alcohols contained as a water-soluble polymer in the present invention include, in addition to ordinary polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate, anion-modified polyvinyl alcohol having an anionic group such as a carboxyl group, and nonionic. Modified polyvinyl alcohols such as nonionic modified polyvinyl alcohol having a functional group and silyl modified polyvinyl alcohol having a silyl group are also included.

  Polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate preferably has an average degree of polymerization of 200 or more, more preferably 1,000 or more, and has an average degree of polymerization of 1,500 to 5,000. Are more preferable, and 2,000 to 5,000 are particularly preferably used. When the polymerization degree of polyvinyl alcohol is 200 or more, there is no crack in the coating film, and when the polymerization degree is 5,000 or less, the coating liquid is stabilized. In addition, that the coating liquid is stable means that the coating liquid is stabilized with time. Hereinafter, the same applies.

  The saponification degree is preferably from 70 to 100%, and more preferably from 80 to 99.5% from the viewpoint of solubility in water.

  The anion-modified polyvinyl alcohol is described in, for example, polyvinyl alcohol having an anionic group as described in JP-A-1-2060888, JP-A-61-237681 and JP-A-63-307979. Examples of such a copolymer 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.

  Examples of the nonion-modified polyvinyl alcohol include, for example, a polyvinyl alcohol derivative in which a polyalkylene oxide group is added to a part of vinyl alcohol as described in JP-A-7-9758, and JP-A-8-25795. Block copolymer of vinyl compound and vinyl alcohol having a hydrophobic group described, silanol-modified polyvinyl alcohol having a silanol group, reactive group modification having a reactive group such as an acetoacetyl group, a carbonyl group, and a carboxyl group Polyvinyl alcohol and the like.

  These polyvinyl alcohols may be used alone or in combination of two or more kinds having different degrees of polymerization and types of modification. As the polyvinyl alcohol, a commercially available product or a synthetic product 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, and PVA-235 (registered trademark, manufactured by Kuraray Co., Ltd.), JC-25, JC-33, JC-40, JF-03, JF -04, JF-05, JP-03, JP-04JP-05, JP-45 (all manufactured by Japan Vineyard Poval Co., Ltd.), RS-4104, RS-2117, RS-1117, RS-2817, RS Exeval (registered trademark, Kuraray Co., Ltd.) such as -1717, RS-1113, RS-1713, and HR-3010, and Nichigo G-Poly Over (registered trademark, manufactured by The Nippon Synthetic Chemical Industry Co., Ltd.), and the like.

  The content of polyvinyl alcohol in the refractive index layer is preferably 3 to 70% by mass, more preferably 5 to 60% by mass, still more preferably 10 to 50% by mass, and particularly preferably, based on the total solid content of the refractive index layer. Is from 13 to 45% by mass. When a plurality of types of polyvinyl alcohols are included, the total is preferably within the above range.

<Curing agent>
In the present invention, a hardener may be used for forming the low refractive index layer and the high refractive index layer. When polyvinyl alcohol is used as the binder resin, the effect can be particularly exhibited.

  The curing agent that can be used together with polyvinyl alcohol is not particularly limited as long as it causes a curing reaction with polyvinyl alcohol, but boric acid and a salt thereof are preferable. Boric acid or a salt thereof refers to an oxygen acid or a salt thereof having a boron atom as a central atom, and specifically, orthoboric acid, diboric acid, metaboric acid, tetraboric acid, pentaboric acid, and octaboric acid. Acids and their salts. Boric acid and borate as a curing agent may be used alone or in a mixture of two or more.

  As the curing agent, besides the above-mentioned boric acid and salts thereof, known ones can be used. Generally, a compound having a group capable of reacting with polyvinyl alcohol or a reaction between different groups of polyvinyl alcohol is used. It is a compound that promotes and is appropriately selected and used. Specific examples of the curing agent include, for example, epoxy curing agents (diglycidyl ethyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-diglycidyl cyclohexane, N, N-diglycidyl- 4-glycidyloxyaniline, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, etc., aldehyde curing agents (formaldehyde, glyoxal, etc.), active halogen 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.

  When each refractive index layer contains a curing agent, the total amount of the curing agent used is preferably 10 to 600 mg, more preferably 20 to 500 mg per 1 g of polyvinyl alcohol (when a plurality of polyvinyl alcohols are used, the total amount). preferable.

<Surfactant>
The low refractive index layer and the high refractive index layer according to the present invention preferably contain a surfactant from the viewpoint of applicability.

  Anionic surfactants, nonionic surfactants, amphoteric surfactants, and the like can be used as the surfactant used for adjusting the surface tension at the time of coating, but an amphoteric surfactant is more preferable.

  As the amphoteric surfactant preferably used in the present invention, there are amide sulfobetaine type, carboxybetaine type, sulfobetaine type, imidazolium type and the like. Specific examples of the amphoteric surfactant preferably used in the present invention are shown below. In the present invention, sulfobetaine type and carboxybetaine type are preferable from the viewpoint of coating unevenness. Examples of products include sofazoline (registered trademark, the same applies hereinafter) LSB-R, LSB, LMEB-R (all manufactured by Kawaken Fine Chemical Co., Ltd.), Amphitol (Registered trademark) 20HD (manufactured by Kao Corporation). The surfactants may be used alone or as a mixture of two or more.

  When each refractive index layer contains a surfactant, the content of the surfactant in the refractive index layer is preferably 0.001 to 1% by mass relative to the total solid content of the refractive index layer. More preferably, it is 005 to 0.80% by mass.

<Other resins>
The low refractive index layer may contain another resin in addition to the water-soluble polymer. Examples of such a resin include a water-dispersible hydrophobic resin. The water-dispersible hydrophobic resin is a resin formed by fusing a hydrophobic polymer dispersed in an aqueous solvent at the time of forming a refractive index layer in a process of manufacturing an optical reflection film. By including such a resin, a film having high hydrophobicity can be obtained when the film is formed by fusion. Therefore, expansion and contraction of the film due to a change in the amount of water in the atmosphere can be reduced, so that cracks can be prevented. Further, the coating film becomes flexible, and the force applied to the coating film when the film expands or contracts due to a change in the amount of moisture in the atmosphere can be reduced.

  The water-dispersible hydrophobic resin may be an emulsion resin. Emulsion resin is a resin in which fine resin particles having an average primary particle size of 2.0 μm or less are dispersed in an emulsion state in an aqueous medium, and an oil-soluble monomer is used as a polymer dispersant. And obtained by emulsion polymerization using a dispersant. The primary average particle size of the emulsion resin can be measured by a dynamic light scattering method.

  Oil-soluble monomers that can be used are not particularly limited, but ethylene, propylene, butadiene, vinyl acetate and its partial hydrolyzate, vinyl ether, acrylic acid and its esters, methacrylic acid and its esters, acrylamide and its derivatives, Methacrylamide and its derivatives, styrene, divinylbenzene, vinyl chloride, vinylidene chloride, maleic acid, vinylpyrrolidone, diisocyanates such as 1,6-hexamethylene diisocyanate, polyisocyanates, diols, polyols, dicarboxylic acids and the like. Can be

  The dispersant that can be used is not particularly limited. For example, in addition to low-molecular dispersants such as alkyl sulfonates, alkylbenzene sulfonates, diethylamine, ethylenediamine, and quaternary ammonium salts, polyoxyethylene nonyl can be used. Polymer dispersants such as phenyl ether, polyethylene ethylene laurate ether, hydroxyethyl cellulose, and polyvinylpyrrolidone are exemplified.

  Examples of the resin to be emulsion-polymerized (emulsion resin) include acrylic resin, styrene-butadiene resin, ethylene-vinyl acetate resin, urethane resin, phenol resin, and acrylate resin.

  Commercially available emulsion resins may be used. For example, Movinyl (registered trademark) 718A, 710A, 731A, LDM7582, 5450, 6960 (all manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), Superflex (registered trademark) Trademarks) 150, 170, 300, 500M, 620, 650 (all manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), Adecabon Titer (registered trademark) HUX-232, HUX-380, HUX-386, HUX-830, HUX- 895 (all manufactured by ADEKA Corporation), AE-116, AE-120A, AE-200A, AE-336B, AE-981A, AE-986B (all manufactured by E-Tech Co., Ltd.), ETERNACOLL (registered trademark) UW-1005E , UW-5002, UW-5034E, UE-550 (Manufactured by Ube Industries, Ltd.), and ACRIT (TM) UW-309, UW-319SX, UW-520 (manufactured by Taisei Fine Chemical Co., Ltd.).

  As the emulsion resin, any of an anionic emulsion resin, a cationic emulsion resin, and a nonionic emulsion resin can be used.

  Although the refractive index of the emulsion resin is not particularly limited, it is preferably from 1.3 to 1.7, and more preferably from 1.4 to 1.6. Within the above range, the refractive index of the water-soluble resin is close to that of the water-soluble resin, so that the haze of the obtained optical reflection film can be reduced.

  The water-dispersible hydrophobic resin may be used singly or as a mixture of two or more.

  When the water-dispersible hydrophobic resin is contained in the refractive index layer, the content of the water-dispersible hydrophobic resin is preferably 1 to 30% by mass, more preferably 3 to 30% by mass based on the total solid content of the refractive index layer. It is 20% by mass, particularly preferably 5 to 10% by mass. When a plurality of types of water-dispersible hydrophobic resins are included, the total is preferably within the above range.

<Other additives>
The low refractive index layer and the high refractive index layer according to the present invention include, 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, JP-A-60-72785, JP-A-61-146591, JP-A-1-95091 and JP-A-3-13376, etc. Fluorescent brighteners described in JP-A-59-42993, JP-A-59-52689, JP-A-62-280069, JP-A-61-242871 and JP-A-4-219266. PH adjusters such as phosphoric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate, defoamers, lubricants such as diethylene glycol, preservatives, Antistatic agents, may contain various known additives such as a matting agent.

≪High refractive index layer≫
The high refractive index layer is not particularly limited as long as it has a higher refractive index than the low refractive index layer. In the present invention, the high refractive index layer is preferably formed by applying a high refractive index layer coating solution. The coating solution for the high refractive index layer may be composed of only the above water-soluble polymer, but preferably contains metal oxide particles from the viewpoint of the refractive index. In addition, by including metal oxide particles, the high refractive index layer can be made cationic, and interfacial mixing is suppressed by utilizing electric repulsion with the cationic polymer contained in the low refractive index layer. be able to. As a result, there is an effect that haze can be effectively suppressed.

<Metal oxide particles contained in high refractive index layer>
Examples of the metal oxide particles used in the high refractive index layer include high refractive index metals such as titanium oxide particles, zirconium oxide particles, zinc oxide particles, alumina particles, colloidal alumina, niobium oxide particles, europium oxide particles, and zircon particles. Oxide particles can be mentioned. In order to adjust the refractive index, the metal oxide particles may be used alone or in combination of two or more.

  The size of the metal oxide particles contained in the high refractive index layer is not particularly limited, but can be defined by a volume average particle diameter or a primary average particle diameter. The volume average particle diameter of the metal oxide particles contained in the high refractive index layer is preferably 100 nm or less, more preferably 1 to 100 nm, and even more preferably 2 to 50 nm. Further, the primary average particle diameter of the metal oxide particles contained in the high refractive index layer is preferably 100 nm or less, more preferably 1 to 100 nm, and further preferably 2 to 50 nm. When the volume average particle diameter or the primary average particle diameter is in the above range, it is preferable from the viewpoint of low haze and excellent visible light transmittance.

  The volume average particle size referred to in the present specification is a method of observing the particles themselves using a laser diffraction scattering method, a dynamic light scattering method, or an electron microscope, or particles appearing on the cross section or surface of the refractive index layer. The size of 1,000 arbitrary particles is measured by a method of observing an image with an electron microscope, and particles having a particle size of d1, d2... Di ... dk are respectively n1, n2. · Ni ... In the group of nk particles, assuming that the volume per particle is vi, the volume average particle diameter is expressed as mv = {(vi · di)} / {(vi)}. The average particle size weighted by the volume to be calculated is calculated.

  The primary average particle diameter can be determined by the primary average particle measurement method described in the section of <Silicon oxide particles> above.

  The content of the metal oxide particles in the high refractive index layer is preferably 15 to 95% by mass, more preferably 20 to 90% by mass, and more preferably 30 to 90% by mass based on the total solid content of the high refractive index layer. Particularly preferred is 90% by mass. When a plurality of types of metal oxide particles are included, the total is preferably within the above range.

In order to form a transparent and higher refractive index layer having a higher refractive index, the high refractive index layer preferably contains titanium oxide particles or zirconium oxide particles having a high refractive index, and particularly preferably contains zirconium oxide particles. . The high refractive index layer containing zirconium oxide particles is transparent and can exhibit a higher refractive index. Further, since the photocatalytic activity is low, the light resistance and weather resistance of the high refractive index layer and the adjacent low refractive index layer are increased. In the present invention, zirconium oxide means zirconium dioxide (ZrO ₂ ).

  The zirconium oxide particles may be cubic or tetragonal, or may be a mixture thereof.

  As the zirconium oxide particles, those obtained by modifying the surface of an aqueous zirconium oxide sol so as to be dispersible in an organic solvent or the like may be used.

  As a method for preparing the zirconium oxide particles or a dispersion thereof, any conventionally known method can be used. For example, as described in JP-A-2014-80361, a method of reacting a zirconium salt with an alkali in water to prepare a slurry of zirconium oxide particles, adding an organic acid, and performing a hydrothermal treatment can be used. .

  Commercially available zirconium oxide particles may be used. For example, SZR-W, SZR-CW, SZR-M, SZR-K, and the like (all manufactured by Sakai Chemical Industry Co., Ltd.) are preferably used. Can be.

  Further, the zirconium oxide particles used in the present invention are preferably monodispersed. Here, the monodispersion means that the degree of monodispersion determined by the following formula is 40% or less. This monodispersity is more preferably 30% or less, particularly preferably 0.1 to 20%.

  The content of the zirconium oxide particles in the high refractive index layer is not particularly limited, but is preferably 15 to 95% by mass, and more preferably 20 to 90% by mass based on the total solid content of the high refractive index layer. It is particularly preferably 30 to 90% by mass. By setting the content in the above range, the optical reflection characteristics can be improved.

  In the optical reflection film according to the present invention, in order to further form a high refractive index layer having a high refractive index, the high refractive index layer includes, in addition to zirconium oxide particles, high refractive index metal oxide fine particles such as titanium oxide particles. May be contained. The content of the zirconium oxide particles is 80 to 100 mass with respect to the total amount of the metal oxide particles used in the high refractive index layer (the total amount of the zirconium oxide particles and the high refractive index metal oxide fine particles other than the zirconium oxide). %, Preferably 90 to 100% by mass, and more preferably 100% by mass.

≪Substrate≫
The optical reflection film according to the present invention includes a substrate for supporting the high refractive index layer and the low refractive index layer. Various resin films can be used as the base material of the optical reflection film, and polyolefin films (polyethylene, polypropylene, etc.), polyester films (polyethylene terephthalate (PET), polyethylene naphthalate, etc.), polyvinyl chloride, cellulose triacetate And the like, and a polyester film is preferable. The polyester film (hereinafter, referred to as polyester) is not particularly limited, but is preferably a film-forming polyester having a dicarboxylic acid component and a diol component as main components.

  The thickness of the substrate used in the present invention is preferably from 10 to 300 μm, particularly preferably from 20 to 150 μm. In addition, two substrates may be stacked, and in this case, the types may be the same or different.

  The base material preferably has a transmittance in the visible light region of 85% or more, and particularly preferably 90% or more, according to JIS R3106 (1998). When the base material has the above transmittance, the transmittance in the visible light region indicated by JIS R3106 (1998) when the infrared shielding film is formed is 50% or more (upper limit: 100%). Is preferred.

  Further, the substrate using the above resin or the like may be an unstretched film or a stretched film. Stretched films are preferred from the viewpoint of improving strength and suppressing thermal expansion.

  The substrate can be manufactured by a conventionally known general method. For example, a resin as a material is melted by an extruder, extruded by an annular die or a T die, and quenched, whereby a substantially amorphous, unoriented, unstretched substrate can be produced. In addition, the unstretched base material is subjected to a known method such as uniaxial stretching, tenter-type sequential biaxial stretching, tenter-type simultaneous biaxial stretching, tubular simultaneous biaxial stretching, or the like, in the flow direction (vertical axis) of the base material, or A stretched base material can be manufactured by stretching in a direction (horizontal axis) perpendicular to the flow direction of the base material.

  Further, the substrate may be subjected to a relaxation treatment or an off-line heat treatment in view of dimensional stability. It is preferable that the relaxation treatment is performed in a process from heat fixing in the stretching film forming process of the polyester film, in a transverse stretching tenter, or winding up after leaving the tenter. The substrate subjected to the relaxation treatment is subjected to off-line heat treatment so that the heat resistance is improved and the dimensional stability is further improved.

  The base material is preferably coated with the undercoat layer coating solution in-line on one or both sides during the film formation process. In addition, the undercoating application during the film forming process is called in-line undercoating. As the resin used for the undercoat layer coating solution, polyester resin, acrylic-modified polyester resin, polyurethane resin, acrylic resin, vinyl resin, vinylidene chloride resin, polyethyleneimine vinylidene resin, polyethyleneimine resin, polyvinyl alcohol resin (polyvinyl alcohol), Modified polyvinyl alcohol resin (modified polyvinyl alcohol), gelatin and the like can be mentioned, and any of them can be preferably used. Conventionally known additives can 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, spray coating and the like.

  In the above-mentioned base material, additives such as stabilizers, surfactants, infrared absorbers, ultraviolet absorbers, flame retardants, antistatic agents, antioxidants, heat stabilizers, lubricants, fillers, coloring Agents, pigments, adhesion regulators, and the like.

(Production method of optical reflection film)
The method for producing an optical reflection film of the present invention uses any method as long as at least one unit composed of the low refractive index layer and the high refractive index layer can be formed on a substrate. Can be

  In the method for producing an optical reflection film of the present invention, the optical reflection film is formed by laminating a unit composed of a low refractive index layer and a high refractive index layer on a substrate.

  Specifically, it is preferable that a low refractive index layer and a high refractive index layer are alternately applied and dried to form a laminate. Specific examples include the following forms: (1) A coating liquid for a high refractive index layer is applied on a substrate and dried to form a high refractive index layer, and then a coating liquid for a low refractive index layer is applied and dried. Forming a low refractive index layer and forming an optical reflection film; (2) coating a low refractive index layer coating solution on a substrate and drying to form a low refractive index layer; A method of forming a high refractive index layer by applying and drying a layer coating liquid to form an optical reflection film; (3) alternately applying a high refractive index layer coating liquid and a low refractive index layer coating liquid on a substrate. A method of forming an optical reflection film including a high refractive index layer and a low refractive index layer by successively applying a multi-layer and drying the coating; and (4) a coating liquid for a high refractive index layer and a low refractive index layer on a substrate. A method of simultaneously coating with a coating solution and drying to form an optical reflection film including a high refractive index layer and a low refractive index layer; and the like.Among them, the method (4), which is a simpler manufacturing process, is preferable. That is, the method for producing an optical reflection film of the present invention preferably includes laminating the high refractive index layer and the low refractive index layer by a simultaneous multilayer coating method.

  In the present invention, in order to form a low-refractive-index layer, the low-refractive-index layer coating solution contains the water-soluble polymer, silicon oxide particles, a cationic polymer, and an amino alcohol containing no carboxyl group. Therefore, the method for producing an optical reflection film is a method for producing an optical reflection film including at least one unit in which a low-refractive-index layer and a high-refractive-index layer are laminated on a substrate, wherein the water-soluble polymer and the oxidized The method includes applying a coating liquid prepared by adding silicon particles, a cationic polymer, and an amino alcohol containing no carboxyl group.

  In preparing the coating solution, the amino alcohol may be added in a solid form or in a solution form. In addition, since the amino alcohol has been described above, the detailed description is omitted here.

  Examples of the coating method include a roll coating method, a rod bar coating method, an air knife coating method, a spray coating method, a curtain coating method, and the methods described in U.S. Pat. Nos. 2,761,419 and 2,761,791. A slide bead coating method using a hopper, an extrusion coating method, and the like are preferably used.

  The solvent for preparing the coating liquid for the high refractive index layer and the coating liquid for the low refractive index layer is not particularly limited, but water, an organic solvent, or a mixed solvent thereof is preferable. In the present invention, it is preferable to use a water-soluble polymer in both the low-refractive-index layer and the high-refractive-index layer. However, by using the water-soluble polymer, coating with an aqueous solvent becomes possible. Further, in the present invention, a cationic polymer is added to the coating solution for the low refractive index layer in order to reduce the haze, but it is preferable to use a cationic polymer having high water solubility. However, in the present invention, the cationic polymer has a cation or a cationic group as described above, whereas the water-soluble polymer in the present invention does not have a cation or a cationic group. Macromolecules) are distinguished from each other. The aqueous solvent does not require large-scale production equipment as compared with the case where an organic solvent is used, and is therefore preferable in terms of productivity and environmental protection.

  When using an organic solvent at the time of preparing the coating liquid, the organic solvent is not particularly limited, for example, alcohols such as methanol, ethanol, ethyl acetate, butyl acetate, esters such as propylene glycol monomethyl ether acetate, diethyl ether, Ethers such as propylene glycol monomethyl ether; amides such as dimethylformamide; ketones such as acetone and methyl ethyl ketone. These organic solvents may be used alone or in combination of two or more.

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

  When using a mixed solvent of water and a small amount of an organic solvent, the content of water in the mixed solvent is preferably 80 to 99.9% by mass, based on 100% by mass of the whole mixed solvent, and 85 to 99% by mass. More preferably, it is 0.5% by mass. Here, when the content is 80% by mass or more, the volume fluctuation due to the volatilization of the solvent can be reduced, and the handling is improved. When the content is 99.9% by mass or less, the homogeneity at the time of adding the liquid is increased, and the stability is improved. This is because the obtained liquid properties can be obtained.

  The concentration of the water-soluble polymer in the coating liquid for the low refractive index layer (when a plurality of types of water-soluble polymers are used, the total concentration thereof) is preferably 0.5 to 10% by mass. Further, the concentration of silicon oxide particles in the coating solution for the low refractive index layer (when a plurality of types of silicon oxide particles are used, the total concentration thereof) is preferably 1 to 50% by mass. In addition, the content of the cationic polymer in the coating solution for the low refractive index layer is preferably adjusted so that the cationic polymer is in the above-described preferable range with respect to the total mass of the silicon oxide particles. Furthermore, it is preferable that the content of the amino alcohol in the coating solution for the low refractive index layer is adjusted so that the amino alcohol is within the above-described preferable range with respect to the total mass of the silicon oxide particles.

  The concentration of the water-soluble polymer in the coating solution for the high refractive index layer (when a plurality of types of water-soluble polymers are used, the total concentration thereof) is preferably 0.5 to 10% by mass. Further, the concentration of the metal oxide particles in the coating liquid for the high refractive index layer (when a plurality of types of metal oxide particles are used, the total concentration thereof) is preferably 1 to 50% by mass.

  The method for preparing the low refractive index layer coating solution is not particularly limited. For example, a water-soluble polymer, silicon oxide particles, a cationic polymer, an amino alcohol, and other additives that are added as necessary are added, and the mixture is stirred. A method of mixing is used. At this time, the order of addition of each component is not particularly limited, and each component may be sequentially added and mixed with stirring, or may be added and mixed at once with stirring.

  The method for preparing the coating solution for the high refractive index layer is not particularly limited. For example, a water-soluble polymer, metal oxide particles such as zirconium oxide particles, and other additives that are added as needed, are added, and stirred. A method of mixing is used. At this time, the order of addition of each component is not particularly limited, and each component may be sequentially added and mixed with stirring, or may be added and mixed at once with stirring.

  Further, as described above, a preferred embodiment of the present invention includes an embodiment in which the high refractive index layer and the low refractive index layer contain polyvinyl alcohol as a water-soluble polymer. In this case, when performing simultaneous multi-layer coating, it is preferable that the polyvinyl alcohol used for the high refractive index layer coating liquid and the low refractive index layer coating liquid have different degrees of saponification. Due to the difference in the degree of saponification, mixing of layers in each of the coating and drying steps can be suppressed. Although this mechanism is not yet clear, it is considered that the mixing is suppressed by the difference in surface tension resulting from the difference in the degree of saponification. In the present invention, the difference in the degree of saponification of polyvinyl alcohol used for the coating liquid for the high refractive index layer and the coating liquid for the low refractive index layer is preferably 3 mol% or more, more preferably 8 mol% or more. That is, the difference between the degree of saponification of the high refractive index layer and the degree of saponification of the low refractive index layer is preferably at least 3 mol%, more preferably at least 8 mol%. The upper limit of the difference between the degree of saponification of the high-refractive index layer and the degree of saponification of the low-refractive index layer is preferably higher in consideration of the effect of suppressing / preventing interlayer mixing between the high-refractive index layer and the low-refractive index layer. Although not limited, it is preferably at most 20 mol%, more preferably at most 15 mol%.

  When comparing the difference in the degree of saponification in each refractive index layer, when each refractive index layer contains a plurality of polyvinyl alcohols (having different degrees of saponification and polymerization), the polyvinyl alcohol having the highest content in the refractive index layer is used. Compare alcohol. Here, in the case of “polyvinyl alcohol having the highest content in the refractive index layer”, the degree of polymerization is calculated on the assumption that polyvinyl alcohols having a difference in saponification degree of 3 mol% or less are the same polyvinyl alcohol. Specifically, when polyvinyl alcohol having a saponification degree of 90 mol%, a saponification degree of 91 mol%, and a saponification degree of 93 mol% is contained in the same layer at 10% by mass, 40% by mass, and 50% by mass, respectively. These three polyvinyl alcohols are the same polyvinyl alcohol, and the degree of saponification of these three mixtures is (90 × 0.1 + 91 × 0.4 + 93 × 0.5) /1=91.9 mol%. The term “polyvinyl alcohol having a difference in the degree of saponification of 3 mol% or less” is sufficient if it is within 3 mol% when focusing on any polyvinyl alcohol, for example, 90, 91, 92, 94 mol%. When the vinyl alcohol of the formula (1) contains 91 mol% of vinyl alcohol, all polyvinyl alcohols are within 3 mol%, so that the same polyvinyl alcohol is obtained.

  When the same layer contains polyvinyl alcohols having different degrees of saponification of 3 mol% or more, it is regarded as a mixture of different polyvinyl alcohols, and the degree of polymerization and the degree of saponification are calculated for each.

  The temperature of the high-refractive-index layer coating solution and the low-refractive-index layer coating solution during simultaneous multilayer coating is preferably in the range of 25 to 60 ° C, and in the range of 30 to 45 ° C when the slide bead coating method is used. Is more preferred. When the curtain coating method is used, a temperature range of 25 to 60C is preferable, and a temperature range of 30 to 45C is more preferable.

  The viscosity of the high-refractive-index layer coating liquid and the low-refractive-index layer coating liquid during simultaneous multilayer coating is not particularly limited. However, when the slide bead coating method is used, the temperature is preferably in the range of 5 to 160 mPa · s, more preferably in the range of 60 to 140 mPa · s, in the above-mentioned preferable temperature range of the coating solution. When the curtain coating method is used, the temperature is preferably in the range of 5 to 1200 mPa · s, and more preferably in the range of 25 to 500 mPa · s, in the preferable temperature range of the coating liquid. Within such a viscosity range, simultaneous multilayer coating can be performed efficiently. According to the present invention, even when a cationic polymer is contained in the coating solution for the low refractive index layer, a good viscosity within the above range can be secured.

  The viscosity of the coating solution at 15 ° C. is preferably 100 mPa · s or more, more preferably 100 to 30,000 mPa · s, and still more preferably 2,500 to 30,000 mPa · s.

  The conditions of the coating and drying methods are not particularly limited. For example, in the case of the sequential coating method, first, one of the high-refractive-index layer coating solution and the low-refractive-index layer coating solution heated to 30 to 60 ° C. After coating and drying on a base material to form a layer, another coating liquid is applied on this layer and dried to form a laminated film precursor (unit). Next, the number of units required to exhibit desired shielding performance is sequentially applied by the above-described method, dried, and laminated to obtain a laminated film precursor. When drying, it is preferable to dry the formed coating film at 30 ° C. or higher. For example, it is preferable to dry at a wet bulb temperature of 5 to 50 ° C. and a film surface temperature of 5 to 100 ° C. (preferably 10 to 50 ° C.), for example, by blowing hot air at 40 to 60 ° C. for 1 to 5 seconds. dry. As a drying method, warm air drying, infrared drying, and microwave drying are used. Further, drying in a multi-stage process is preferable to drying in a single process, and it is more preferable that the temperature in the constant rate drying section <the temperature in the decreasing rate drying section. In this case, the temperature range of the constant rate drying section is preferably 30 to 60 ° C, and the temperature range of the reduced rate drying section is preferably 50 to 100 ° C.

  The conditions for the coating and drying methods in the case of performing simultaneous multi-layer coating are as follows: the high-refractive-index layer coating solution and the low-refractive-index layer coating solution are heated to 30 to 60 ° C. After the simultaneous multi-layer coating of the liquid and the low-refractive-index layer coating liquid, the temperature of the formed coating film is preferably once cooled to 1 to 15 ° C (set), and then dried at 10 ° C or higher. More preferable drying conditions are a wet bulb temperature of 5 to 50 ° C and a film surface temperature of 10 to 50 ° C. For example, it is dried by blowing warm air of 40 to 80 ° C. for 1 to 5 seconds. Further, as a cooling method immediately after the application, it is preferable to perform a horizontal setting method from the viewpoint of improving the uniformity of the formed coating film.

  Here, the above-mentioned set means that the viscosity of the coating film composition is increased by means of lowering the temperature by applying cold air or the like to the coating film, and the fluidity of the substance in each interlayer and in each layer is reduced, and Means the process of forming A state in which cold air is applied to the coating film from the surface and the finger is pressed against the surface of the coating film and the finger no longer sticks is defined as a setting completed state.

  The time (set time) from the time of application to the completion of setting by applying cool air is preferably within 5 minutes, more preferably within 2 minutes. Although the lower limit time is not particularly limited, it is preferable to take a time of 45 seconds or more. If the setting time is too short, mixing of the components in the layer may be insufficient. On the other hand, if the setting time is too long, interlayer diffusion of the metal oxide particles proceeds, and the difference in the refractive index between the high refractive index layer and the low refractive index layer may be insufficient.

  The setting time is adjusted by adjusting the concentration of the water-soluble polymer (polyvinyl alcohol), the concentration of the metal oxide particles, and various known gelling agents such as gelatin, pectin, agar, carrageenan, and gellan gum. Can be adjusted by adding the component (1).

  The temperature of the cold air is preferably from 0 to 25 ° C, more preferably from 5 to 10 ° C. The time during which the coating film is exposed to cold air depends on the transport speed of the coating film, but is preferably 10 to 360 seconds, more preferably 10 to 300 seconds, and still more preferably 10 to 120 seconds.

  The high-refractive-index layer coating solution and the low-refractive-index layer coating solution may be applied in such a manner as to have a preferable thickness when dried as described below.

(Membrane design)
The optical reflection film of the present invention includes at least one unit in which a high refractive index layer and a low refractive index layer are laminated. Preferably, on one or both sides of the substrate, there is a multilayer optical interference film formed by alternately laminating high refractive index layers and low refractive index layers. From the viewpoint of productivity, the preferable range of the total number of the high refractive index layers and the low refractive index layers on one side of the substrate is 100 or less, more preferably 45 or less. The lower limit of the range of the total number of preferred high refractive index layers and low refractive index layers per one side of the substrate is not particularly limited, but is preferably 5 or more.

  Incidentally, the range of the total number of the preferred high refractive index layer and the low refractive index layer is applicable even when laminated on only one side of the substrate, in the case of being simultaneously laminated on both sides of the substrate Is also applicable. When laminated on both surfaces of the substrate, the total number of high refractive index layers and low refractive index layers on one surface of the substrate and the other surface may be the same or different. Further, in the optical reflection film of the present invention, the lowermost layer (the layer in contact with the substrate) and the outermost layer may be either a high refractive index layer or a low refractive index layer.

  In general, in the optical reflection film, it is preferable to design a large difference in the refractive index between the high refractive index layer and the low refractive index layer from the viewpoint that the reflectance for a desired light beam can be increased with a small number of layers. . In the present invention, the difference in refractive index between at least two adjacent layers (the high refractive index layer and the low refractive index layer) is preferably 0.15 or more, more preferably 0.2 or more, and particularly preferably 0 or more. .21 or more. The upper limit is not particularly limited, but is usually 0.5 or less.

  The difference in the refractive index and the required number of layers can be calculated using commercially available optical design software.

  When alternately laminating a high refractive index layer and a low refractive index layer in the optical reflection film, the refractive index difference between the high refractive index layer and the low refractive index layer is within the range of the preferred refractive index difference. Is preferred. However, for example, when the outermost layer is formed as a layer for protecting the film, or when the lowermost layer is formed as an adhesion improving layer with the substrate, the uppermost layer and the lowermost layer are preferably The configuration may be outside the range of the refractive index difference.

  Reflection at the interface between adjacent layers (the interface between the high refractive index layer and the low refractive index layer) depends on the refractive index ratio between the layers. Therefore, the greater the refractive index ratio, the higher the reflectance. When the light path difference between the reflected light on the surface of the layer and the reflected light on the bottom of the layer is expressed as n · d = wavelength / 4 when viewed as a single-layer film, control is performed so that the reflected light is enhanced by the phase difference. And reflectivity can be increased. Here, n is the refractive index, d is the physical thickness of the layer, and n · d is the optical thickness. By utilizing this optical path difference, reflection can be controlled. Utilizing this relationship, the refractive index and the film thickness of each layer are controlled to control the reflection of visible light and near-infrared light. That is, the reflectance in a specific wavelength region can be increased by the refractive index of each layer, the thickness of each layer, and the manner of stacking each layer.

  The optical reflection film of the present invention can be made into a visible light reflection film or a near infrared reflection film by changing a specific wavelength region having a high reflectance. That is, if the specific wavelength region having a high reflectance is set in the visible light region, the film becomes a visible light reflecting film, and if it is set in the near infrared region, the film becomes a near infrared reflecting film. If a specific wavelength region having a high reflectance is set in an ultraviolet light region, an ultraviolet reflective film is obtained. When the optical reflection film of the present invention is used as a heat shielding film, it may be a (near) infrared reflection (shielding) film. In the case of an infrared reflective film, a multilayer film in which films having different refractive indices are laminated on a polymer film is formed, and the transmittance at 550 nm in the visible light region indicated by JIS R3106 (1998) is 50% or more. Is preferably 70% or more, more preferably 75% or more. Further, the transmittance at 1200 nm is preferably 35% or less, more preferably 25% or less, and further preferably 20% or less. It is preferable to design the optical film thickness and the unit so as to have such a preferable range. Further, it is preferable to have a region having a reflectance exceeding 50% in a region of a wavelength of 900 nm to 1400 nm.

  The infrared region of the incident spectrum of the solar direct light is related to the rise in the room temperature, and by blocking this, the rise in the room temperature can be suppressed. Looking at the cumulative energy ratio from the shortest wavelength (760 nm) to the longest wavelength of 3200 nm based on the weighting factor described in Japanese Industrial Standards JIS R3106 (1998), the red energy from the wavelength of 760 nm to the longest wavelength of 3200 nm When the accumulated energy from 760 nm to each wavelength is calculated when the total energy of the entire outer region is 100, the total energy from 760 to 1300 nm occupies about 75% of the entire infrared region. Therefore, shielding the wavelength region up to 1300 nm is effective in the energy saving effect by the heat ray shielding.

  The low refractive index layer preferably has a refractive index of 1.10 to 1.60, and more preferably 1.30 to 1.50. The high refractive index layer preferably has a refractive index of 1.65 to 1.8, and more preferably 1.7 to 1.75.

  The thickness (thickness after drying) per one layer (excluding the lowermost layer and the outermost layer) of the refractive index layer is preferably 20 to 1000 nm, more preferably 50 to 500 nm, and more preferably 50 to 350 nm. Is more preferable.

  The total thickness (including the substrate) of the optical reflection film of the present invention is preferably 12 to 315 μm, more preferably 15 to 200 μm, and further preferably 20 to 100 μm.

  Further, in order to improve the optical characteristics, the haze of the optical reflection film is preferably small, more preferably 0 to 1.5%, and particularly preferably 0 to 1.2%. In addition, haze shall indicate the value measured by the method of the Example.

(Layer configuration of optical reflection film)
The optical reflection film includes at least one unit in which a low refractive index layer and a high refractive index layer are laminated on a substrate. The unit may be formed on only one side of the substrate, or may be formed on both sides. The unit is preferably formed on both surfaces of the substrate because the reflectance at a specific wavelength is improved.

  The optical reflection film is provided under the base material or on the outermost surface layer on the side opposite to the base material, for the purpose of adding further functions, a conductive layer, an antistatic layer, a gas barrier layer, an easy adhesion layer (adhesion layer), Antifouling layer, deodorant layer, drip layer, slippery layer, hard coat layer, abrasion resistant layer, antireflection layer, electromagnetic wave shielding layer, ultraviolet absorbing layer, infrared absorbing 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 above high refractive index layer and low refractive index layer, coloring layer (visible light absorbing layer), interlayer film used for laminated glass It may have one or more functional layers such as layers.

  The order of laminating the above-described various functional layers in the optical reflection film is not particularly limited.

  For example, in a specification in which an optical reflection film is stuck (inside stuck) on the indoor side of a window glass, an optical reflection layer and an adhesive layer each including at least one unit in which the high refractive index layer and the low refractive index layer are laminated on the base material surface. Are preferred, and a hard coat layer is applied on the surface of the substrate on the side opposite to the side on which these layers are laminated, as a preferred example. In addition, the order of the adhesive layer, the base material, the optical reflection layer, and the hard coat layer may be in this order, and further, another functional layer, a base material, or an infrared absorber may be included. In addition, a preferred example of the specification in which the optical reflection film of the present invention is stuck (outside stuck) to the outdoor side of a window glass is as follows. An optical reflection layer and an adhesive layer are stacked on the substrate surface in this order, and these layers are further stacked. This is a configuration in which a hard coat layer is provided on the surface of the base material on the side opposite to the side on which it is provided. As in the case of the inner coating, the adhesive layer, the base material, the optical reflection layer, the hard coat layer may be in this order, and may further have another functional layer base material, or an infrared absorber. .

[Application of Optical Reflective Film: Optical Reflector]
The optical reflection film of the present invention can be applied to a wide range of fields. For example, an optical reflector is provided in which the optical reflection film is provided on at least one surface of a base. The optical reflection film of the present invention can be used for the purpose of enhancing weather resistance. For example, a film for window application such as a heat ray reflection film which gives a heat ray reflection effect, and a film for a greenhouse for agriculture, which is attached to equipment (substrate) exposed to sunlight for a long time, such as an outdoor window of a building or an automobile window. And the like. In particular, it is suitable for a member in which the optical reflection film according to the present invention is bonded to a substrate such as glass or a glass substitute resin directly or via an adhesive.

  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, 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 resin may be any of a thermoplastic resin, a thermosetting resin, and an ionizing radiation-curable resin, and may be used in combination of two or more. The substrate can be manufactured by a known method such as extrusion molding, calender molding, injection molding, hollow molding, and compression molding. The thickness of the substrate is not particularly limited, but is usually 0.1 mm to 5 cm.

  It is preferable that the adhesive layer or the pressure-sensitive adhesive layer for bonding the optical reflection film and the substrate is provided such that the optical reflection film is on the sunlight (heat ray) incident surface side when bonded to a window glass or the like. Also, when the optical reflection film is sandwiched between the window glass and the base material, it can be sealed from ambient gas such as moisture, which is preferable in durability. Even if the optical reflection film of the present invention is installed outdoors or outside a car (for external application), it is preferable because of its environmental durability.

  As an adhesive applicable to the present invention, an adhesive mainly containing a photo-curable or thermosetting resin can be used. The adhesive preferably has durability to ultraviolet rays, and is preferably an acrylic adhesive or a silicone adhesive.

  Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto. In the examples, “parts” or “%” is used, but “parts by weight” or “% by weight” is used unless otherwise specified. Unless otherwise specified, each operation was performed at room temperature (25 ° C.).

[Production Example 1: Production of coating liquid 1 for high refractive index layer]
An aqueous citric acid solution (1.9% by mass) was added to 384.8 g of a 30% by mass dispersion of zirconium oxide particles (SZR-W, zirconia sol, particle size distribution: D50 3 nm to 5 nm, manufactured by Sakai Chemical Industry Co., Ltd.). 175.4 g were added. 1.94 g of a 5% by mass aqueous solution of a surfactant (Softazoline (registered trademark) LMEB-R, manufactured by Kawaken Fine Chemical Co., Ltd.) was added thereto, and the mixture was heated to 40 ° C. Next, 120.4 g of an 8% by mass aqueous solution of ethylene-modified polyvinyl alcohol (Exeval (registered trademark) RS-2117, manufactured by Kuraray Co., Ltd., saponification degree: 97.5 to 99 mol%) was further added, and 9.9 g of pure water was further added. Was added. After stirring this for 10 minutes, 240.8 g of a 6% by mass aqueous solution of polyvinyl alcohol (JC-40, saponification degree: 99 mol%-manufactured by Nippon Vinevar Co., Ltd.) and 66.7 g of pure water were added. Thereafter, the mixture was stirred at 40 ° C. for 180 minutes to obtain a coating liquid 1 for a high refractive index layer.

  The refractive index of the single layer produced using the high refractive index layer coating solution 1 was 1.73. The method for measuring the refractive index is as follows (the same applies hereinafter).

(Measurement of single-layer refractive index of each layer)
In order to measure the refractive index, a sample was prepared by applying the high refractive index layer coating solution 1 in a single layer on a substrate, and the sample was cut into 10 cm × 10 cm, and the refractive index was determined according to the following method. . Using a spectrophotometer U-4100 (solid sample measurement system) manufactured by Hitachi, Ltd., roughen the surface (back surface) opposite to the measurement surface of each sample, and then absorb light with a black spray. The treatment was performed to prevent reflection of light on the back surface, and the reflectance of 400 nm to 2500 nm was measured under the condition of 5 ° regular reflection, and the refractive index was determined from the result. The following refractive index was set to 1000 nm in consideration of the wavelength dependence of the refractive index.

[Production Example 2: Production of low refractive index layer coating liquid 1]
6.77 g of diallylamine hydrochloride polymer (including a secondary amine salt) (PAS-21CL, weight average molecular weight 50,000, 25% by mass aqueous solution, manufactured by Nitto Bo Medical Co., Ltd.) as a cationic polymer in a stirring vessel, and 26.1 g of water And boric acid (3% by mass aqueous solution) (16.05 g) were mixed. To this was added 245.16 g of a 10% by mass aqueous solution of acidic colloidal silica (ST-OXS, primary average particle size: 4 to 6 nm, manufactured by Nissan Chemical Industries, Ltd.). Further, N-ethylethanolamine (an amount of 0.06% by mass based on the total solid content of colloidal silica) as an amino alcohol was added, and the mixture was heated to 40 ° C. while stirring. Here, 183.9 g of an 8% by mass aqueous solution of polyvinyl alcohol (JP-45, degree of polymerization: 4500, degree of saponification: 88 mol%, manufactured by Nippon Vineyard Co., Ltd.), 26% by mass of an aqueous urethane resin (emulsion resin, superflex ( (Registered trademark) 650, Daiichi Kogyo Seiyaku Co., Ltd.) and 6.3 g of a 5% by mass surfactant solution (Softazoline (registered trademark) LMEB-R, Kawaken Fine Chemical Co., Ltd.) are added and stirred at 40 ° C. To obtain a coating liquid 1 for a low refractive index layer. The refractive index of the single layer produced using the low refractive index layer coating solution 1 was 1.48.

[Production Examples 3 to 6: Preparation of low refractive index layer coating liquids 2 to 5]
Low refractive index was obtained in the same manner as in Production Example 1 except that the type of amino alcohol was changed in Production Example 2 (preparation of coating liquid for low refractive index layer 1) and the amino alcohol was changed to those shown in Table 1 below. Rate layer coating solutions 2 to 5 were respectively prepared. The refractive indices of the single layers prepared using the low refractive index layer coating solutions 2 to 5 were all 1.48.

[Production Examples 7 to 9 and 11: Preparation of Coating Solutions 6 to 8 and 10 for Low Refractive Index Layer]
In the above Production Example 6 (preparation of coating liquid for low refractive index layer 5), low refractive index was obtained in the same manner as in Production Example 1 except that the kind of the cationic polymer was changed to those shown in Table 1 below. Rate layer coating solutions 6 to 8 and 10 were prepared, respectively. The refractive index of each of the single layers produced using the above low refractive index layer coating solutions 6 to 8 and 10 was 1.48.

  As the cationic polymer, 5.37 g of polyaluminum chloride (Takibaine (registered trademark) # 1500, 23% by mass aqueous solution, manufactured by Taki Kagaku Co., Ltd.) was used in the low refractive index layer coating liquid 6, and the low refractive index layer coating liquid 7 was used as the cationic polymer. 3.33 g of a methyldiallylamine hydrochloride polymer (including a tertiary amine salt) (PAS M-1, weight average molecular weight 20,000, 50% by mass aqueous solution, manufactured by Nittobo Medical Co., Ltd.), low refractive index layer coating For Liquid 8, 5.95 g of diallyldimethylammonium chloride polymer (containing a quaternary ammonium group) (PASH-5, weight average molecular weight 30,000, 28% by mass aqueous solution, manufactured by Nittobo Medical Co., Ltd.) was used. . In the low-refractive-index layer coating liquid 10, 2.02 g of the above methyldiallylamine hydrochloride polymer (PAS M-1) and 2.45 g of the diallyldimethylammonium chloride polymer (PASH-5) were used as the cationic polymers. Used as a mixture.

[Production Examples 10 and 12 to 14: Production of Low Refractive Index Layer Coating Liquids 9 and 11 to 13]
Same as Production Example 11 except that in Production Example 11 (preparation of coating liquid for low refractive index layer 10), the added amount of amino alcohol was changed to be the amounts shown in Table 1 below, respectively. Thus, coating liquids for low refractive index layers 9 and 11 to 13 were prepared, respectively. The refractive index of each of the single layers prepared using the low refractive index layer coating solutions 9 and 11 to 13 was 1.48.

[Production Example 15: Preparation of coating liquid 14 for low refractive index layer]
A low-refractive-index layer coating liquid 14 was prepared in the same manner as in Production Example 2 except that amino alcohol and a cationic polymer were not added in Production Example 2 (preparation of low-refractive-index layer coating liquid 1). The refractive index of the single layer produced using the low refractive index layer coating solution 14 was 1.48.

[Production Example 16: Preparation of coating liquid 15 for low refractive index layer]
A low-refractive-index layer coating liquid 15 was prepared in the same manner as in Production Example 2 except that amino alcohol was not added in Production Example 2 (preparation of low-refractive-index layer coating liquid 1). The refractive index of the single layer produced using the low refractive index layer coating solution 15 was 1.48.

[Production Example 17: Production of low refractive index layer coating liquid 16]
A low-refractive-index layer coating liquid 16 was prepared in the same manner as in Production Example 2 except that serine was added instead of amino alcohol in the above-mentioned Production Example 2 (preparation of low-refractive-index layer coating liquid 1). The amount of serine added was 0.48% by mass based on the total solid content of colloidal silica. The refractive index of the single layer produced using the low refractive index layer coating solution 16 was 1.48.

<Example 1>
Using a slide bead (slide hopper) coating apparatus capable of applying a 21-layer multi-layer coating, the high-refractive-index layer coating liquid 1 and the low-refractive-index layer coating liquid 1 prepared as described above were kept at 40 ° C. and 50 μm in thickness. (A4300, manufactured by Toyobo Co., Ltd., double-sided adhesive layer, length 200 m × width 210 mm). At this time, a total of 21 layers were simultaneously coated so that the lowermost layer and the uppermost layer (outermost layer) were low refractive index layers, and the other layers were alternately high refractive index layers and low refractive index layers. . At this time, the thickness at the time of drying is adjusted so that the lowermost layer is 1510 nm, the outermost layer is 100 nm, the lower refractive index layers other than the lowermost layer and the low refractive index layers are 150 nm, and the high refractive index layers are 150 nm. did.

  Immediately after the application, cold air at 5 ° C. was sprayed to increase the viscosity. After thickening, hot air of 80 ° C. was blown and dried to produce an optical reflection film 1 having a total of 21 optical reflection layers.

<Examples 2 to 13 and Comparative Examples 1 to 3>
In Example 1, the optical reflection film was formed in the same manner as in Example 1 except that the coating liquids used for forming the low refractive index layer were changed to the low refractive index layer coating liquids 2 to 16 shown in Table 1, respectively. 2 to 13 and Comparative Optical Reflective Films 1 to 3 were produced, respectively. In Table 1, the content of amino alcohol (or a compound corresponding thereto) indicates a ratio (% by mass) to the mass of the silicon oxide particles.

[Evaluation]
(Evaluation of coating unevenness)
The optical reflection films obtained in the above Examples and Comparative Examples were visually observed under sunlight and fluorescent light, respectively, and evaluated according to the following criteria. In the following evaluation criteria, 3 to 5 are judged to be acceptable.

-Evaluation criteria-
5: No problem when viewed with sunlight 4: No problem with fluorescent light, but slight slight unevenness when viewed with sunlight 3: No problem with fluorescent light, but unevenness when viewed with sunlight 2: Only slight unevenness is observed with a fluorescent lamp, and the unevenness is clearly seen when viewed with sunlight. 1: The unevenness is clearly seen with a fluorescent lamp even when viewed with sunlight.

(Haze measurement)
The haze of each of the optical reflection films obtained in the above Examples and Comparative Examples was measured by a haze meter (NDH2000, manufactured by Nippon Denshoku Industries Co., Ltd.). In addition, the light source of the haze meter was a halogen bulb of 5V9W, and the light receiving unit used a silicon photocell (with a relative luminous efficiency filter). The haze was measured at 23 ° C. and 55% RH. The haze value of the optical reflection film is preferably 1.2% or less.

  The results of the various evaluations are shown in Table 1 below. In Comparative Example 3, serine was added in place of the amino alcohol in the present invention, and the item related to “amino alcohol” described the compound. In Example 6, since an inorganic polymer was used as the cationic polymer, the item relating to the “cationic group” described the type of the cationic polymer. In addition, about a cationic polymer, "PAS-M1" is abbreviated as "M1" and "PAS-H5" is abbreviated as "H5".

  From Table 1 above, it was shown that the optical reflection film having the configuration according to the present invention also suppressed application unevenness in addition to haze. In particular, comparison of Examples 1 to 5 showed that it is preferable to use tris (hydroxymethyl) aminomethane as the amino alcohol. Further, the comparison of Examples 5 to 8 and 10 showed that the haze was further reduced by selecting the cationic polymer so as to contain both the tertiary amino group and the quaternary ammonium group.

Claims (7)

An optical reflection film including at least one unit in which a low refractive index layer and a high refractive index layer are laminated on a base material,
An optical reflection film, wherein the low refractive index layer contains a water-soluble polymer, silicon oxide particles, a cationic polymer, and an amino alcohol containing no carboxyl group.   The optical reflection film according to claim 1, wherein the amino alcohol is a dihydric alcohol or a trihydric alcohol.   The optical reflection film according to claim 1, wherein the amino alcohol has a primary amino group.   The optical reflection film according to any one of claims 1 to 3, wherein the amino alcohol is tris (hydroxymethyl) aminomethane.   The cationic polymer according to any one of claims 1 to 4, wherein the cationic polymer includes at least one cationic group selected from the group consisting of a tertiary amino group, a cation of a tertiary amino group, and a quaternary ammonium group. Item 6. The optical reflection film according to item 1.   The optical reflection film according to any one of claims 1 to 5, wherein the content of the amino alcohol in the low refractive index layer is 0.05 to 2% by mass based on the total amount of the silicon oxide particles. .   The method for producing an optical reflection film according to any one of claims 1 to 6, comprising laminating the high refractive index layer and the low refractive index layer by a simultaneous multilayer coating method.