JP2016138906A - Optical reflective film and optical reflector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical reflective film having a low haze and a high infrared reflection effect, in which interfacial disorder or interfacial mixing in an interface is prevented when a high refractive index layer and a low refractive index layer are laminated, and adhesiveness (resistance to layer peeling) is improved, and to provide an optical reflector including the optical reflective film.SOLUTION: The optical reflective film of the present invention has an optical reflective layer laminate, in which five or more optical reflective layer units each composed of a high refractive index layer and a low refractive index layer having different refractive indices from each other are stacked, disposed on at least one surface side of a substrate. The low refractive index layer comprises two or more binder resins, in which at least one binder resin is a polyester resin and the polyester resin is included within the range from 5.0 to 30 mass% in the whole binder resin amount of the low refractive index layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical reflection film and an optical reflector, and more particularly, to an optical reflection film that prevents interfacial mixing between a plurality of refractive index layers and has improved adhesion and haze resistance, and an optical reflector including the same.

  In recent years, it was theoretically supported that a laminated film in which a light reflecting layer including a high refractive index layer and a low refractive index layer is disposed on a substrate selectively reflects light of a specific wavelength. Therefore, the above laminated film is used in various applications as an optical reflection film that shields light having a predetermined wavelength. For example, heat insulation glass with high heat insulation or heat insulation properties is distributed in the market in order to block the heat felt by human skin due to the influence of sunlight entering from the car window and to suppress the operation of the air conditioner in the car to save energy. ing. Recently, with the widespread use of electric vehicles and the like, a laminated film in which a plurality of high refractive index layers and low refractive index layers that transmit visible light and shield infrared rays that are heat rays are laminated from the viewpoint of increasing the cooling efficiency inside the vehicle. Infrared (heat ray) reflective films having the above are used for vehicle members and the like.

  However, when a large number of high refractive index layers and low refractive index layers having different configurations are laminated, there is a problem in that the layer interface is disturbed, resulting in an increase in haze.

  For example, a high refractive index layer containing a high refractive index pigment and a binding polymer compound, and a low refractive index layer containing a low refractive index pigment and a binding polymer compound are laminated on the substrate, and at least one of them. A method of preventing discoloration due to heat by containing a xerogel compound in the refractive index layer is disclosed (for example, see Patent Document 1). However, when a high refractive index layer and a low refractive index layer are laminated in a state where a gelling agent that forms a xerogel compound proposed in Patent Document 1 is added, the interface between the high refractive index layer and the low refractive index layer In this case, there is a problem in that the disturbance occurs and the interface region is mixed, so that the infrared reflectivity is low and the haze is deteriorated.

  Further, in a system in which a high refractive index layer and a low refractive index layer are laminated, since different materials (for example, a binder resin and metal fine particles) are used for the high refractive index layer and the low refractive index layer, adhesion is insufficient. When exposed to sunlight, etc. for a long time, for example, after sticking a seal such as an automobile inspection seal on the optical reflective film surface, when trying to peel off, between the high refractive index layer and the low refractive index layer In some cases, delamination may occur.

JP 2013-64915 A

  The present invention has been made in view of the above problems, and its solution is to prevent disturbance and interfacial mixing at the interface when the high refractive index layer and the low refractive index layer are laminated, and adhesion (film peeling). It is to provide an optical reflection film having improved, low haze and high infrared reflection effect, and an optical reflector provided with the same.

  As a result of diligent investigation in view of the above problems, the present inventor, on at least one surface side of the substrate, an optical reflection layer unit composed of a high refractive index layer and a low refractive index layer having at least different refractive indexes, It has an optical reflection layer laminate in which 5 units or more are laminated, wherein the low refractive index layer contains two or more binder resins, and at least one of the binder resins contains a polyester resin in a specific ratio. The optical reflection film makes it possible to prevent disturbance and interfacial mixing at the interface when laminating a high refractive index layer and a low refractive index layer, improve adhesion (film peeling), low haze, and high infrared reflection effect The present inventors have found that an optical reflective film having the above can be provided, and have reached the present invention.

  That is, the said subject of this invention is solved by the following means.

1. An optical reflective film having an optical reflective layer laminate in which five or more optical reflective layer units each composed of a high refractive index layer and a low refractive index layer having different refractive indexes are laminated on at least one surface side of a substrate. There,
The low refractive index layer contains two or more binder resins, at least one of the binder resins is a polyester resin, and the polyester resin is added to 5.0 to 30 of the total binder resin amount of the low refractive index layer. An optical reflection film, which is contained within a mass% range.

  2. 2. The optical reflective film as set forth in claim 1, wherein the polyester resin has a sulfonic acid group at least partially.

  3. The low refractive index layer contains metal oxide particles, and the ratio (F / B) of the mass of the metal oxide particles (F) to the total mass of the binder resin (B) is 0.5 to 3.0. The optical reflection film according to item 1 or 2, wherein the optical reflection film falls within the range of.

  4). 4. The optical reflective film as described in item 3, wherein the metal oxide particles contained in the low refractive index layer are silica particles having a secondary average particle diameter of 50 nm or less.

  5. The number of lamination of the optical reflection layer unit composed of the high refractive index layer and the low refractive index layer is in the range of 5 to 20 units, any one of items 1 to 4 The optical reflective film as described in 2.

  6). An optical reflector comprising the optical reflective film according to any one of items 1 to 5 on at least one surface side of a substrate.

  By the above-mentioned means of the present invention, the disturbance and interfacial mixing at the interface when the high refractive index layer and the low refractive index layer are laminated are prevented, adhesion (film peeling) is improved, low haze, and high infrared reflection effect And an optical reflector provided with the optical reflective film.

  Although the expression mechanism and action mechanism that could achieve the above-described effects by the optical reflection film having the configuration defined in the present invention are not all clear, they are presumed as follows.

  Conventionally, in an optical reflective film having an optical reflective layer laminate in which an optical reflective layer unit composed of a high refractive index layer and a low refractive index layer is laminated a plurality of times, as described above, the high refractive index layer and the low refractive index When the layers are laminated, there is a problem that infrared reflectivity is lowered and haze is also deteriorated due to disturbance or interfacial mixing at the interface between the high refractive index layer and the low refractive index layer. In addition, the high refractive index layer and the low refractive index layer are formed of different materials, resulting in insufficient adhesion. There is a problem that delamination occurs between the low refractive index layers.

  In the present invention, based on the above problems, as a result of intensive investigations on the improvement means, by using a polyester resin at a specific ratio for the low refractive index layer, the interface between the high refractive index layer and the low refractive index layer. Mixing was prevented, and adhesion between both layers could be dramatically improved.

  In addition, in the conventional configuration, if the ratio of the metal fine particles to the binder resin is simply lowered, the crack resistance improves when the weather resistance is evaluated, but the adhesion deteriorates and the adjacent layers are mixed at the same time. However, in the present invention, by applying a polyester resin at a specific ratio to the low refractive index layer, all of the above characteristics are improved. I was able to.

  As a technical reason for this, it is presumed that by applying a polyester resin as the binder resin, the main binder resin and the polyester resin interact to make it difficult for particles in the adjacent layer to enter. Furthermore, when particles enter the low refractive index layer, it is presumed that the interaction between the particles and the main binder resin and the polyester resin works and the interlayer mixing property is improved.

Schematic sectional view showing an example of the configuration of the optical reflective film of the present invention Schematic sectional view showing another example of the configuration of the optical reflective film of the present invention Schematic sectional drawing which shows an example of a structure of the optical reflector (laminated glass) which comprised the optical reflection film of this invention

  The optical reflective film of the present invention is an optical reflective layer in which five or more optical reflective layer units each composed of a high refractive index layer and a low refractive index layer having different refractive indexes are laminated on at least one surface side of a substrate. It has a laminate, the low refractive index layer contains two or more binder resins, at least one of the binder resins is a polyester resin, and the total amount of binder resin in the low refractive index layer is the polyester resin. In a range of 5.0 to 30% by mass. This feature is a technical feature common to the inventions according to claims 1 to 6.

  As an embodiment of the present invention, from the viewpoint of more manifesting the intended effect of the present invention, by adding a sulfonic acid group to at least a part of the polyester resin, the water solubility of the polyester resin is further improved, and wet coating is performed. It is preferable from the viewpoint of further improving the adhesion with the high refractive index layer when laminated by the method.

  The low refractive index layer contains metal oxide particles, and the ratio (F / B) of the mass of the metal oxide particles (F) and the total mass of the binder resin (B) is 0.5 to 3.0. The adhesion ratio between the high refractive index layer and the low refractive index layer is further improved by lowering the content ratio of the metal oxide particles (F) within the range and setting a larger amount of the binder resin. This is preferable.

  In the conventional configuration, simply reducing the ratio of the metal fine particles to the binder resin improves the cracking resistance when the weather resistance evaluation is performed, but the adhesion deteriorates, and at the same time, adjacent layers are easily mixed. However, in the present invention, by applying a polyester resin at a specific ratio to the low refractive index layer, any of the above can be improved. Can do.

  Moreover, it is preferable from the viewpoint that lower haze characteristics can be obtained by using silica particles having a secondary average particle diameter of 50 nm or less as the metal oxide particles contained in the low refractive index layer.

  Moreover, when the number of laminated optical reflection layer units composed of a high refractive index layer and a low refractive index layer is in the range of 5 to 20 units, an infrared reflection effect and shielding effect can be obtained efficiently. From the viewpoint of being able to.

  Moreover, by providing the optical reflective film of the present invention on a substrate, an optical reflector having an excellent infrared shielding effect such as laminated glass can be obtained.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, "-" shown in the following description is used with the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

<< Basic structure of optical reflection film and optical reflector >>
First, the basic configuration of the optical reflective film and the optical reflector of the present invention will be described with reference to the drawings. In the description of each figure, the number described in parentheses at the end of the component represents the reference numeral in each figure.

  The optical reflective film of the present invention comprises 5 optical reflective layer units each comprising at least one high refractive index layer and a low refractive index layer containing a polyester resin in a specific range on at least one surface side of the substrate. It is the structure which has the optical reflection layer laminated body which laminated | stacked the unit or more.

  Furthermore, the typical structure of the optical reflective film of this invention is demonstrated using figures. However, the optical reflection film described here is an example, and is not limited thereto.

  FIG. 1 shows an optical reflecting film according to the present invention, in which a plurality of optical reflecting layer units each composed of a high refractive index layer and a low refractive index layer having different refractive indexes are laminated on one surface side of a substrate. It is a schematic sectional drawing which shows an example of a structure of the optical reflection film which has a reflection layer laminated body.

In FIG. 1, an optical reflective film (1) of the present invention comprises a low refractive index layer and a high refractive index layer (for example, refractive index layer T ₁ ) having different refractive indexes on a substrate (2), preferably a transparent substrate. And an optical reflection layer laminate (ML) in which a plurality of optical reflection layer units (U) constituted by the refractive index layer T ₂ ) are laminated.

The optical reflection layer laminate (ML) is composed of n layers of refractive index layers T _{1 to} T _n , for example, T ₁ , T ₃ , T ₅ , (omitted), T _n-2 , and T _n are refractive indexes. Is composed of a low refractive index layer containing a polyester resin having a specific range of 1.10 to 1.60, and T ₂ , T ₄ , T ₆ , (omitted), and T _n-1 are refractive indexes. An example is a configuration in which a high refractive index layer has a refractive index in the range of 1.70 to 2.50. In the optical reflective film (1) having the configuration shown in FIG. 1, the number of laminated optical reflective layer units is n / 2. The refractive index as used in the field of this invention is the value measured in the environment of 25 degreeC.

  FIG. 2 is a schematic cross-sectional view showing a configuration having optical reflection layer laminates (MLa, MLb) on both surfaces of the substrate (2) as another example of the configuration of the optical reflection film (1) of the present invention. .

  In contrast to the configuration illustrated in FIG. 1 above, an optical reflective layer laminate (MLa) in which a plurality of optical reflective layer units (U) are laminated on one surface side of the base material (2), An optical reflective film (1) is formed by providing an optical reflective layer laminate (MLb) in which a plurality of optical reflective layer units (U) are laminated.

In the structure shown in FIG. 2, the optical reflecting layer stack (MLa), is composed of n layers of refractive index layers _Ta 1 to Ta _n, for _{example, Ta 1, Ta 3, Ta} 5, ( omission), Ta _{n -2,} the refractive index of Ta _n is constituted by a low refractive index layer containing a specific range of a polyester resin which is in the range of _{1.10~1.60, Ta 2, Ta 4,} Ta 6, ( omission) , Tan _-1 is composed of a high refractive index layer having a refractive index in the range of 1.70 to 2.50. Similarly, the optical reflective layer stack (MLb) is composed of refractive index layers Tb _{1 to} Tb _n. A specific polyester resin having a refractive index in the range of 1.10 to 1.60, for example, Tb ₁ , Tb ₃ , Tb ₅ , (omitted), Tb _n-2 , Tb _n containing in a range constituted by the low refractive index _{layer, Tb 2, Tb 4, Tb} 6, ( omission), Tb Configuration in which the refractive index is the high refractive index layer is in the range of 1.70 to 2.50 _-1 it can be cited as an example.

  Moreover, in the optical reflective film (1) of this invention, it is a preferable aspect that the refractive index layer adjacent to a base material (1) and the refractive index layer of the outermost layer are all low refractive index layers.

  The total thickness of the optical reflective film of the present invention is not particularly limited, but is in the range of 40 to 600 μm, preferably in the range of 40 to 500 μm, and more preferably in the range of 50 to 400 μm.

  As an optical characteristic of the optical reflection film of the present invention, it is preferable to have light transmittance, and the visible light transmittance measured by JIS R3106 (1998) is preferably 60% or more, more preferably 70. % Or more, and more preferably 80% or more. Moreover, it is preferable to have the area | region exceeding a reflectance of 50% in the area | region of wavelength 900-1400 nm.

  FIG. 3 is a schematic cross-sectional view showing an example of the configuration of an optical reflector provided with the optical reflective film of the present invention on a substrate.

  The optical reflector (3) shown in FIG. 3 has an optical reflective film (1) having the structure shown in FIG. 1 and a base (5A and 5B) on each surface via an adhesive layer (4A and 4B). For example, it is the structure clamped by the glass substrate.

  As the optical reflector (3) having such a configuration, for example, it can be used as a laminated glass used for a window glass of a building, a windshield of a vehicle body, or the like, and can reflect or shield infrared rays from the outdoors.

<Structure of optical reflection film>
Next, details of each element constituting the optical reflection film of the present invention will be described.

  The optical reflective film of the present invention is characterized by having an optical reflective layer laminate in which a plurality of optical reflective layer units composed of a high refractive index layer and a low refractive index layer having different refractive indexes are laminated.

[Definition of high refractive index layer and low refractive index layer]
In this specification, the terms “high refractive index layer” and “low refractive index layer” refer to a refractive index layer having a higher refractive index when comparing the refractive index difference between two adjacent layers. It means that the lower refractive index layer is a low refractive index layer. Therefore, the terms “high refractive index layer” and “low refractive index layer” are the same when the refractive index layers constituting the optical reflective film are focused on two adjacent refractive index layers. All forms other than those having a refractive index are included.

  In the present invention, the low refractive index layer preferably contains at least the first binder resin and the first metal oxide particles, and in the first binder resin, at least the polyester resin has a total binder resin amount of 5. It contains within the range of 0-30 mass%. The high refractive index layer preferably contains at least a second binder resin and second metal oxide particles.

  As described above, the optical reflective film of the present invention constitutes an optical reflective layer laminate in which five or more optical reflective layer units in which a high refractive index layer and a low refractive index layer are laminated are laminated. The high refractive index layer and the low refractive index layer are defined as follows.

  For example, a component that constitutes a high refractive index layer (hereinafter referred to as a high refractive index layer component) and a component that constitutes a low refractive index layer (hereinafter referred to as a low refractive index layer component) are mixed at the respective adjacent layer interfaces, resulting in high refraction. A mixed layer composed of a mixture of the refractive index layer component and the low refractive index layer component may be formed. In this case, in the mixed layer, a region where the content ratio of the high refractive index layer component is 50% by mass or more is defined as a high refractive index layer, and a region where the content ratio of the low refractive index layer component exceeds 50% by mass is defined as the low refractive index layer. And

  Specifically, when the low refractive index layer contains, for example, a first metal oxide as a low refractive index component, and the high refractive index layer contains a second metal oxide as a high refractive index component The concentration profile of the metal oxide in the film thickness direction in these optical reflective layer laminates is measured, and can be regarded as a high refractive index layer region or a low refractive index layer region depending on the composition ratio.

  The concentration profile of the metal oxide in this optical reflective layer laminate is, for example, etching from the surface to the depth direction using a sputtering method, and applying XPS (X-ray Photoelectron Spectroscopy, X-ray photoelectron spectroscopy). Using an XPS surface analyzer, the outermost surface is set to 0 nm, sputtering is performed at a rate of 0.5 nm / min, and the atomic composition ratio can be measured. Further, the low refractive index component or the high refractive index component does not contain metal oxide particles, and either the high refractive index layer or the low refractive index layer is formed only from a water-soluble resin (organic binder). Similarly, in the optical reflection layer laminate, the concentration profile of the water-soluble resin (organic binder) is confirmed, for example, by measuring the carbon concentration in the film thickness direction, so that a mixed region exists, Furthermore, by measuring the composition by EDX (Energy Dispersive X-ray spectroscopy), the target layer etched by sputtering can be regarded as a high refractive index layer or a low refractive index layer. .

  The optical reflective layer laminate according to the present invention is characterized in that it has a constitution in which 5 units or more are laminated, preferably 5 to 20 units.

  In the optical reflective film (optical reflective film) of the present invention, the preferred refractive index of the high refractive index layer is in the range of 1.70 to 2.50, more preferably in the range of 1.80 to 2.20. is there. The low refractive index layer according to the present invention preferably has a refractive index in the range of 1.10 to 1.60, more preferably in the range of 1.30 to 1.55. More preferably, it is in the range of 30 to 1.50.

  In the optical reflective film of the present invention, it is preferable to design a large difference in refractive index between the high refractive index layer and the low refractive index layer from the viewpoint of increasing the infrared reflectance with a small number of layers. In the invention, in at least one of the units composed of the high refractive index layer and the low refractive index layer, the difference in refractive index between the adjacent high refractive index layer and low refractive index layer is preferably 0.1 or more. More preferably, it is 0.3 or more. However, regarding the outermost layer and the lowermost layer, a configuration outside the requirements defined above may be used.

  The reflectance in a specific wavelength region is determined by the difference in refractive index between two adjacent layers (high refractive index layer and low refractive index layer) and the number of layers, and the larger the refractive index difference, the same reflectance can be obtained with a smaller number of layers. . The refractive index difference and the required number of layers can be calculated using commercially available optical design software. For example, in order to obtain an infrared shielding ratio of 90% or more, if the difference in refractive index is smaller than 0.1, it is necessary to laminate more than 100 layers, which not only decreases productivity but also scattering at the interface of the layers. Increases and transparency decreases. From the viewpoint of improving reflectivity and reducing the number of layers, there is no upper limit to the difference in refractive index, but the limit is substantially about 1.40.

[Main constituent materials of each refractive index layer]
(Polyester resin: low refractive index layer)
In the low refractive index layer according to the present invention, two or more binder resins are contained, and at least one of the binder resins, the polyester resin is 5.0 to 30% by mass of the total binder resin amount of the low refractive index layer. It is contained within the range.

  Furthermore, it is preferably a water-soluble polyester resin having a sulfonic acid group in at least a part (in the polymer skeleton) of the polyester resin used in the present invention, and more preferably a sulfonic acid metal base as the sulfonic acid group. Further, a water-dispersible emulsion (latex) type may be used.

  The water-soluble polyester resin is a dicarboxylic acid component composed of dicarboxylic acids or reactive derivatives thereof, a diol component composed of diols or ester derivatives thereof, and a water-solubilizing component such as a sulfonic acid group. It is a copolymer obtained by condensing these components as a main component and having a solubility in water. The solubility in water may be appropriately selected and determined, and can be adjusted by the content of a water-solubilizing component, for example, a sulfonic acid group. In addition, the water-soluble polyester resin as used in the field of this invention is a water-soluble polyester resin, and means the state which the said polyester resin melt | dissolves 0.001g or more with respect to 100g of water of 25 degreeC.

  The dicarboxylic acids that are raw materials for the water-soluble polyester resin according to the present invention may be either aromatic dicarboxylic acids or aliphatic dicarboxylic acids, but aromatic dicarboxylic acids are preferred from the viewpoint of the heat resistance of the resin composition.

  Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, and 4,4′-biphenyl ether. Dicarboxylic acid, 4,4'-biphenylmethane dicarboxylic acid, 4,4'-biphenylsulfone dicarboxylic acid, 4,4'-biphenylisopropylidenedicarboxylic acid, 1,2-bis (phenoxy) ethane-4,4'-dicarboxylic Acid, 2,5-anthracene dicarboxylic acid, 2,6-anthracene dicarboxylic acid, 4,4'-p-terphenylenedicarboxylic acid, 2,5-pyridinedicarboxylic acid, etc. -Alkyl group-substituted products such as methyl isophthalic acid) and reactive derivatives (eg Le dimethyl, alkyl ester derivatives such as diethyl terephthalate) and the like can also be used. Among these, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and alkyl ester derivatives thereof are more preferable.

  These aromatic dicarboxylic acids may be used alone or in combination of two or more, and together with the aromatic dicarboxylic acid, an aliphatic dicarboxylic acid such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, etc. One or more alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid may be used in combination.

  Diols that are raw materials for water-soluble polyester resins include, for example, ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentane. Aliphatic diols such as diol, 1,6-hexanediol, decamethylene glycol, 2,2-dimethyl-1,3-propanediol; 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, Cycloaliphatic diols such as cyclohexanediol, trans- or cis-2,2,4,4-tetramethyl-1,3-cyclobutanediol; p-xylenediol, bisphenol A, tetrabromobisphenol A, tetrabromo Fragrance such as bisphenol A-bis (2-hydroxyethyl ether) There may be mentioned diols and the like can be also used these substituents.

  Among these, from the viewpoint of heat resistance of the binder resin, ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,4-cyclohexanedimethanol are preferable, and ethylene glycol and 1,3-propanediol are more preferable. 1,4-butanediol is preferred, and ethylene glycol is particularly preferred.

  These diols may be used alone or in combination of two or more. Further, as the diol component, a long chain diol having a molecular weight of 400 to 6000, specifically, one or more of polyethylene glycol, poly-1,3-propylene glycol, polytetramethylene glycol and the like are used in combination with the diols. And may be copolymerized.

  Examples of the water-solubility-imparting component that is a raw material for the water-soluble polyester resin include dicarboxylic acids having a sulfonic acid metal salt, polyethylene glycol, and the like. Among these, from the viewpoint of water solubility and heat resistance, metal sulfonate is used as a sulfonic acid group. Dicarboxylic acids having a base are preferred.

  Examples of dicarboxylic acids having a sulfonic acid metal base include, for example, sodium such as 5-sulfoisophthalic acid, 2-sulfoisophthalic acid, 4-sulfoisophthalic acid, sulfoterephthalic acid, 4-sulfonaphthalene-2,6-dicarboxylic acid, Examples include alkali metal salts such as potassium or ester-forming derivatives thereof, and 5-sodium sulfoisophthalic acid or an ester derivative thereof is preferable from the viewpoint of water solubility.

  As the content of the dicarboxylic acid having a sulfonic acid metal base, if the amount is too small, the water solubility of the resulting polyester resin becomes insufficient, and conversely, if the amount is too large, the heat resistance of the water soluble polyester resin may be insufficient. Therefore, the content is preferably in the range of 1 to 40 mol%, more preferably in the range of 10 to 37 mol%, based on the total carboxylic acid component that is the raw material of the water-soluble polyester resin. Is preferred.

  Preferable specific examples of the water-soluble polyester resin applicable to the present invention include a copolymer composed of terephthalic acid, ethylene glycol, and 5-sodium sulfoisophthalic acid. “Plus Coat Z-221”, “Plus Coat Z-561”, “Plus Coat Z-446” (above, trade name) and the like are available.

(Binder resin)
In the present invention, the low refractive index layer contains the first binder resin, and the high refractive index layer contains the second binder resin. By using a binder resin as a material for forming each refractive index layer, preferably a water-soluble binder resin as a coating film forming material, a wet coating method such as a gravure printing method, a flexographic printing method, a screen printing is used as a method for forming each layer. Method, roll coating method, bar coating method, dip coating method, spin coating method, casting method, die coating method, blade coating method, bar coating method, gravure coating method, curtain coating method, spray coating method, doctor coating method, inkjet method Etc. can be used for lamination.

  These wet coating methods have a wide range of choices because the coating apparatus to be used is simple and the heat resistance of the substrate does not matter, and is an effective film forming method particularly when a resin substrate is used as the substrate. For example, by applying a wet coating method, a mass production method such as a roll-to-roll method can be adopted, which is advantageous in terms of cost and process time. In addition, each refractive index layer containing a binder resin is highly flexible, so even if it is rolled up during production or transportation, these defects do not easily occur, and it has the advantage of being easy to handle. is there.

<Binder resin of low refractive index layer>
In addition to the water-soluble polyester resin, a conventionally known binder resin can be used for the low refractive index layer according to the present invention.

  In the low refractive index layer according to the present invention, it is particularly preferable to use a polyvinyl alcohol resin as a binder resin together with the water-soluble polyester resin according to the present invention.

  The polyvinyl alcohol obtained by hydrolyzing vinyl acetate preferably has an average degree of polymerization of 1000 or more, and particularly preferably has an average degree of polymerization of 1500 to 5000. The saponification degree is preferably 70 to 100%, and particularly preferably 80 to 99.9%.

  As the polyvinyl alcohol used in the present invention, a synthetic product or a commercially available product may be used. As an example of the commercial item used as polyvinyl alcohol (A) and (B), for example, PVA-102, PVA-103, PVA-105, PVA-110, PVA-117, PVA-120, PVA-124, PVA -203, PVA-205, PVA-210, PVA-217, PVA-220, PVA-224, PVA-235 (manufactured by Kuraray Co., Ltd.), JC-25, JC-33, JF-03, JF-04 , JF-05, JP-03, JP-04JP-05, JP-45 (above, manufactured by Nihon Vinegar & Poval Co., Ltd.) and the like.

  As long as the effects of the present invention are not impaired, the binder resin according to the present invention may contain modified polyvinyl alcohol partially modified in addition to normal polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate. When such a modified polyvinyl alcohol is included, the adhesion, water resistance, and flexibility of the film may be improved.

  Examples of the modified polyvinyl alcohol include cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, nonion-modified polyvinyl alcohol, and vinyl alcohol polymers. Also, vinyl acetate resins (for example, “Exeval” manufactured by Kuraray Co., Ltd.), polyvinyl acetal resins obtained by reacting polyvinyl alcohol with aldehydes (for example, “ESREC” manufactured by Sekisui Chemical Co., Ltd.), silanols having silanol groups Modified polyvinyl alcohol (for example, “R-1130” manufactured by Kuraray Co., Ltd.), modified polyvinyl alcohol resin having an acetoacetyl group in the molecule (for example, “Gosefimer (registered trademark) Z / manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) WR series ") and the like are also included in the polyvinyl alcohol resin.

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

  Nonionic modified polyvinyl alcohol includes, for example, a polyvinyl alcohol derivative in which a polyalkylene oxide group as described in JP-A-7-9758 is added to a part of vinyl alcohol, and JP-A-8-25795. Block copolymer of vinyl compound having hydrophobic group and vinyl alcohol as described, silanol-modified polyvinyl alcohol having silanol group, reactivity having reactive group such as acetoacetyl group, carbonyl group, carboxy group Examples thereof include group-modified polyvinyl alcohol.

  Examples of the cation-modified polyvinyl alcohol include primary to tertiary amino groups and quaternary ammonium groups as described in JP-A No. 61-10383. Polyvinyl alcohol contained therein and obtained by saponifying a copolymer of an ethylenically unsaturated monomer having a cationic group and vinyl acetate.

  Examples of the vinyl alcohol-based polymer include EXEVAL (trade name: manufactured by Kuraray Co., Ltd.) and Nichigo G polymer (trade name: manufactured by Nippon Synthetic Chemical Industry Co., Ltd.).

  The above water-soluble polymer can be used in combination with the water-soluble polyester resin according to the present invention. The water-soluble polymer may be a synthetic product or a commercial product.

  In the low refractive index layer, in addition to the above-described water-soluble polyester resin and polyvinyl alcohol-based resin, other binder resins can be applied within a range that does not impair the object effects of the present invention. For example, polyethylene naphthalate (PEN) ) And its isomers (eg 2,6-, 1,4-, 1,5-, 2,7- and 2,3-PEN), polyalkylene terephthalates (eg polyethylene terephthalate, polypropylene terephthalate, polybutylene) Terephthalate and poly-1,4-cyclohexanedimethylene terephthalate), polyimide (eg, polyacrylimide), polyetherimide, atactic polystyrene, polycarbonate, polymethacrylate (eg, polyisobutyl methacrylate, polypropylmeta) Relate, polyethyl methacrylate, and polymethyl methacrylate), poly (meth) acrylates (eg, polybutyl acrylate and polymethyl acrylate), cellulose derivatives (eg, ethyl cellulose, cellulose acetate, cellulose propionate, cellulose acetate butyrate, and nitric acid) Cellulose), polyalkylene polymers (eg, polyethylene, polypropylene, polybutylene, polyisobutylene, and poly (4-methyl) pentene), fluorinated polymers (eg, perfluoroalkoxy resins, polytetrafluoroethylene, fluorinated ethylene-propylene copolymers) , Polyvinylidene fluoride, and polychlorotrifluoroethylene), chlorinated polymers (eg, polyvinylidene chloride and polyvinyl chloride), poly Sulfone, polyether sulfone, polyacrylonitrile, polyamide, silicone resins, epoxy resins, polyvinylacetate, polyether amides, ionomeric resins, elastomers (e.g., polybutadiene, polyisoprene, and neoprene), and polyurethanes. A copolymer, for example a copolymer of PEN (for example 2,6-, 1,4-, 1,5-, 2,7- and / or 2,3-naphthalenedicarboxylic acid or an ester thereof; Acid or ester thereof, (b) isophthalic acid or ester thereof, (c) phthalic acid or ester thereof, (d) alkane glycol, (e) cycloalkane glycol (for example, cyclohexanedimethanol diol), (f) alkanedicarboxylic acid Or (g) a copolymer with a cycloalkanedicarboxylic acid (eg, cyclohexanedicarboxylic acid), a copolymer of a polyalkylene terephthalate (eg, terephthalic acid or an ester thereof, (a) naphthalene dicarboxylic acid or an ester thereof, and (b) isophthalic acid Acid or its ester (C) phthalic acid or its ester, (d) alkane glycol, (e) cycloalkane glycol (eg, cyclohexanedimethanol diol), (f) alkane dicarboxylic acid, and / or (g) cycloalkane dicarboxylic acid (eg, Copolymers), styrene copolymers (e.g. styrene-butadiene copolymers and styrene-acrylonitrile copolymers), and copolymers of 4,4'-dibenzoic acid and ethylene glycol.

<Binder resin of high refractive index layer>
As the binder resin applicable to the high refractive index layer, it is particularly preferable to apply the same polyvinyl alcohol-based resin as described in the low refractive index layer from the viewpoint of good film formability. Polycarbonate, poly (meth) acrylate and the like can be used.

  1 type may be sufficient as binder resin which comprises a high refractive index layer, and 2 or more types may be sufficient as it.

  The poly (meth) acrylate is a polymer of acrylic acid ester or methacrylic acid ester, and examples thereof include polymethyl methacrylate and polyethyl methacrylate.

  The weight average molecular weight of the polycarbonate and poly (meth) acrylate contained in the high refractive index layer is about 10,000 to 1,000,000, and preferably 50,000 to 800,000. In addition, the value measured by gel permeation chromatography (GPC) is employ | adopted for a weight average molecular weight.

<Other water-soluble inder resins>
Furthermore, examples of other water-soluble binder resins applicable to the low refractive index layer and the high refractive index layer according to the present invention include gelatin, celluloses, thickening polysaccharides, and polymers having reactive functional groups. For example, JP 2012-27288 A, JP 2012-139938 A, JP 2012-185342 A, JP 2012-215733 A, JP 2012-220708 A, for example. JP, 2012-242644, JP 2012-252137, JP 2013-4916, JP 2013-97248, JP 2013-148849, JP 2014-89347, JP Please refer to the descriptions in Japanese Unexamined Patent Application Publication No. 2014-201550 and Japanese Unexamined Patent Application Publication No. 2014-215513. Kill.

(Metal oxide particles)
In the present invention, the low refractive index layer and the high refractive index layer preferably contain metal oxide particles.

<Metal oxide particles in the low refractive index layer: first metal oxide particles>
Examples of the first metal oxide particles used in the low refractive index layer of the present invention include silicon dioxide such as zinc oxide, synthetic amorphous silica, and colloidal silica, alumina, and colloidal alumina. In the present invention, in order to adjust the refractive index, the first metal oxide may be used alone or in combination of two or more.

  In the low refractive index layer according to the present invention, it is preferable to use silica particles having a secondary average particle diameter of 50 nm or less as the first metal oxide particles.

  The silica particles that are the first metal oxide particles contained in the low refractive index layer according to the present invention preferably have a secondary average particle diameter (number average) of 50 nm or less, but within a range of 3 to 50 nm. It is more preferable that it is 10-50 nm. In the present invention, the secondary average particle diameter (number average) of the silica particles as the metal oxide particles is determined by measuring the cross section of the low refractive index layer constituting the optical reflection film or the surface of the low refractive index layer with an electron microscope. The secondary particle diameter of 200 arbitrary silica particles is measured, and is obtained as a simple average value (number average). Here, the particle diameter of each silica particle is represented by a diameter assuming a circle equal to the projected area.

  Silica particles having a secondary average particle size of 50 nm or less applied to the present invention are also referred to as colloidal silica, and are obtained by heating and aging a silica sol obtained by metathesis with an acid of sodium silicate or 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, 63-17807, JP 4-93284, JP 5-278324, JP 6-92011, JP 6-183134, JP 6-297830. JP-A-7-81214, JP-A-7-101142, JP-A-7-179029, JP-A-7-137431, International It may be mentioned those described in, Hirakidai 1994/26530 pamphlet.

  As the colloidal silica, a synthetic product or a commercially available product may be used. Examples of commercially available products include the following Snowtex series sold by Nissan Chemical Industries, Ltd.

Snowtex ST-XS (primary particle size: 4-6 nm, alkaline, dispersion stabilizer: NaOH)
Snowtex ST-S (primary particle size: 8-11 nm, alkaline, dispersion stabilizer: NaOH)
Snowtex ST-30 (Primary particle size: 10-15 nm, alkaline, dispersion stabilizer: NaOH)
Snowtex ST-50 (primary particle size: 20-25 nm, alkaline, dispersion stabilizer: NaOH)
Snowtex ST-30L (primary particle size: 40-50 nm, alkaline, dispersion stabilizer: NaOH)
Snowtex ST-NSX (primary particle size: 4-6 nm, alkaline, dispersion stabilizer: NH ₄ OH)
Snowtex ST-N (Primary particle size: 10-15 nm, alkaline, dispersion stabilizer: NH ₄ OH)
Snowtex ST-N-40 (primary particle size: 20 to 25 nm, alkaline, dispersion stabilizer: NH ₄ OH)
Snowtex ST-OXS (Primary particle size: 4-6nm, acidic, no dispersion stabilizer added)
Snowtex ST-OS (Primary particle size: 8-11 nm, acidic, no dispersion stabilizer added)
Snowtex ST-O (primary particle size: 10-15 nm, acidic, no dispersion stabilizer added)
Snowtex ST-O-40 (Primary particle size: 20 to 25 nm, acidic, no dispersion stabilizer added)
Snowtex ST-OL (primary particle size: 40-50 nm, acidic, no dispersion stabilizer added)
The surface of the colloidal silica may be cation-modified, or may be treated with Al, Ca, Mg, Ba or the like.

  The content of the first metal oxide particles in the low refractive index layer is preferably in the range of 20 to 75% by mass, and 30 to 70% by mass with respect to 100% by mass of the total solid content of the low refractive index layer. % Is more preferable, a range of 35 to 69% by mass is further preferable, and a range of 40 to 68% by mass is particularly preferable. When the content is 20% by mass or more, a desired refractive index is obtained, and when it is 75% by mass or less, the coating property is good, which is preferable.

  In the present invention, the ratio (F / B) of the mass of the first metal oxide particles (F) and the total mass of the first binder resin (B) in the low refractive index layer is 0.5-3. Is preferably within the range of 0.0 in view of achieving excellent interlayer adhesion.

<Metal oxide particles in high refractive index layer: second metal oxide particles>
The high refractive index layer according to the present invention preferably contains second metal oxide particles. The second metal oxide particles applied to the high refractive index layer are preferably different from the first metal oxide particles applied to the low refractive index layer described above.

  Examples of the metal oxide particles used in the high refractive index layer according to the present invention include titanium oxide, zirconium oxide, zinc oxide, alumina, colloidal alumina, niobium oxide, europium oxide, and zircon. In the present invention, in order to adjust the refractive index, the second metal oxide may be used alone or in combination of two or more.

  In the present invention, in order to form a transparent and higher refractive index layer having a higher refractive index, the high refractive index layer includes metal oxide particles having a high refractive index such as titanium and zirconia, that is, titanium oxide particles, oxidized It is preferable to contain zirconia particles. Moreover, it is more preferable to contain rutile (tetragonal) titanium oxide particles having a volume average particle size of 100 nm or less. A plurality of types of titanium oxide particles may be mixed.

  In addition, the first metal oxide particles contained in the low refractive index layer and the second metal oxide particles contained in the high refractive index layer are in a state of having ionicity (that is, the electric charges have the same sign). It is preferable. For example, in the case of simultaneous multi-layer coating, if the ionicity is different, it may react at the interface to produce aggregates, and haze may increase. As means for aligning ionicity, for example, when silica particles (anions) are used for the low refractive index layer and titanium oxide (cations) are used for the high refractive index layer, silicon dioxide is treated with aluminum or the like to be cationized, Alternatively, as described later, titanium oxide can be anionized by treatment with a silicon-containing hydrated oxide.

  The second metal oxide particles contained in the high refractive index layer according to the present invention preferably have a secondary average particle diameter of 3 to 100 nm, and more preferably 3 to 50 nm.

  In addition, the second metal oxide particles contained in the high refractive index layer are preferable from the viewpoint of low haze and excellent visible light transmittance if the secondary average particle diameter is 100 nm or less.

  The secondary average particle diameter here is the volume average particle diameter of the secondary particles, and can be measured by a laser diffraction / scattering method, a dynamic light scattering method, or the like.

  Specifically, the particles themselves or the particles appearing on the cross section or surface of the high refractive index layer are observed with an electron microscope, and the particle size of 200 arbitrary particles is measured and obtained as a simple average value (number average). It is done. Here, the particle diameter of each second metal oxide particle is expressed by a diameter assuming a circle equal to the projected area.

  As content of the metal oxide particle in a high refractive index layer, it is preferable to exist in the range of 15-85 mass% with respect to 100 mass% of total solids of a high refractive index layer, and 20-80 mass%. More preferably, it is in the range, and further preferably in the range of 30 to 75% by mass. By setting it as the said range, it can be set as the favorable infrared shielding property.

  The titanium oxide particles preferably used as the second metal oxide particles according to the present invention are preferably those obtained by modifying the surface of the titanium oxide sol so that it can be dispersed in water or an organic solvent.

  Examples of the preparation method of the aqueous titanium oxide sol include, for example, JP-A-63-17221, JP-A-7-819, JP-A-9-165218, JP-A-11-43327, JP-A-63-3. Reference can be made to the matters described in Japanese Patent No. 17221.

  When titanium oxide particles are used as the second metal oxide particles, for example, “Titanium oxide—physical properties and applied technology” Manabu Seino p255-258 (2000) Gihodo Publishing Co., Ltd. Alternatively, the method of step (2) described in paragraph numbers 0011 to 0023 of International Publication No. 2007/039953 can be referred to.

The second metal oxide particles according to the present invention are preferably in the form of core-shell particles in which titanium oxide particles are coated with a silicon-containing hydrated oxide. As the core-shell particles, the volume average particle diameter of the titanium oxide particles as the core part is preferably more than 1 nm and less than 30 nm, more preferably 4 nm or more and less than 30 nm, and the surface of the titanium oxide particles is used as the core titanium oxide. This is a structure in which a shell made of silicon-containing hydrated oxide is coated such that the coating amount of silicon-containing hydrated oxide is 3 to 30% by mass as SiO _{2 with} respect to 100% by mass. In the present invention, by including the core-shell particles as the second metal oxide particles, the interaction between the silicon-containing hydrated oxide of the shell layer and the binder resin causes the high-refractive index layer and the low-refractive index layer to There is an effect that mixing between layers is suppressed.

  In the present invention, the silicon-containing hydrated oxide may be any of a hydrate of an inorganic silicon compound, a hydrolyzate and / or a condensate of an organosilicon compound, and has a silanol group in order to obtain the effects of the present invention. It is more preferable. Therefore, in the present invention, the second metal oxide particles are preferably silica-modified (silanol-modified) titanium oxide particles in which the titanium oxide particles are silica-modified.

  The coating amount of the silicon-containing hydrated compound of titanium oxide is within the range of 3 to 30% by mass, preferably within the range of 3 to 10% by mass, more preferably 3 to 8% by mass with respect to 100% by mass of titanium oxide. %. This is because when the coating amount is 30% by mass or less, the desired refractive index of the high refractive index layer can be obtained, and when the coating amount is 3% or more, particles can be stably formed.

  Regarding the details of other titanium oxide particles, for example, JP2012-27288A, JP2012-13938A, JP2012-185342A, JP2012-215733A, JP2012-220708A. JP, 2012-242644, JP 2012-252137, JP 2013-4916, JP 2013-97248, JP 2013-148849, JP 2014-89347, Reference can be made to the descriptions in JP 2014-201450 A, JP 2014-215513 A, and the like.

(Other additives applicable to each refractive index layer)
Various additives applicable to the high refractive index layer and the low refractive index layer according to the present invention are listed below. For example, ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988, and JP-A-62-261476, JP-A-57-74192, and JP-A-57-87989. , JP-A-60-27285, JP-A-61-14659, JP-A-1-95091, JP-A-3-13376, etc. Or various nonionic surfactants, JP-A-59-42993, JP-A-59-52689, JP-A-62-280069, JP-A-61-228771, and JP-A-4-219266. Optical brighteners, sulfuric acid, phosphoric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate, etc. Lubricants such as tylene glycol, antiseptics, antifungal agents, antistatic agents, matting agents, heat stabilizers, antioxidants, flame retardants, crystal nucleating agents, inorganic particles, organic particles, thickeners, lubricants, infrared absorption Examples include various known additives such as agents, dyes, and pigments.

[Other constituent layers of optical reflection film]
In the optical reflective film of the present invention, a conductive layer, an antistatic layer, a gas barrier layer, an easy adhesion layer (adhesive layer), an antifouling layer, a deodorizing layer, Flowing layer, slippery layer, hard coat layer, wear-resistant layer, electromagnetic wave shielding layer, ultraviolet absorbing layer, infrared absorbing layer, printed layer, fluorescent light emitting layer, hologram layer, colored layer (visible light absorbing layer), etc. You may have a functional layer.

  For example, regarding the hard coat layer, the contents described in paragraphs (0112) to (0125) of JP-A-2014-201450 can be referred to.

〔Base material〕
The substrate used for the optical reflective film of the present invention is not particularly limited as long as it is formed of a transparent organic material.

  Examples of the base material applicable to the present invention include methacrylate ester, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polyarylate, polystyrene (PS), aromatic polyamide, and polyether ether. Examples thereof include a film made of a resin such as ketone, polysulfone, polyethersulfone, polyimide, and polyetherimide, and a resin film obtained by laminating two or more layers of the resin. From the viewpoint of cost and availability, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC) and the like are preferably used.

  As for the thickness of a base material, about 5-200 micrometers is preferable, More preferably, it is 15-150 micrometers. Two or more substrates may be stacked, and in this case, the types of the substrates may be the same or different.

  The substrate preferably has a visible light transmittance of 85% or more as shown in JIS R3106-1998, particularly preferably 90% or more. It is advantageous and preferable in that the transmittance of the visible light region shown in JIS R3106-1998 when the substrate is an optical reflection film is 50% or more when the substrate has the above transmittance.

  In addition, the base material using the resin or the like may be an unstretched film or a stretched film. A stretched film is preferable from the viewpoint of strength improvement and thermal expansion suppression.

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

  In addition, the base material may be subjected to relaxation treatment or off-line heat treatment in terms of dimensional stability. It is preferable that the relaxation treatment is performed in a process from the heat setting in the stretching process of the polyester film to the winding in the transversely stretched tenter or after exiting the tenter. The relaxation treatment is preferably performed at a treatment temperature of 80 to 200 ° C, more preferably a treatment temperature of 100 to 180 ° C. Moreover, it is preferable that the relaxation rate is in the range of 0.1 to 10% in both the longitudinal direction and the width direction, and more preferably, the relaxation rate is 2 to 6%. The relaxed base material is subjected to the following off-line heat treatment to improve heat resistance and to improve dimensional stability.

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

<< Method for Producing Optical Reflective Film >>
There is no restriction | limiting in particular about the manufacturing method of the optical reflection film of this invention, The optical reflection layer unit comprised from the high-refractive-index layer and the low-refractive-index layer containing at least polyester resin as binder resin on a base material is 5 Any method can be used as long as it can form units or more.

  The optical reflective film of the present invention is formed by laminating an optical reflective layer unit composed of a high refractive index layer and a low refractive index layer on a substrate, for example, a coating liquid for a high refractive index layer and a low refractive index. The layer coating liquid is alternately laminated and applied, and then dried to form an optical reflective layer laminate.

  For example, a coating solution for a low refractive index layer containing a first metal oxide particle, a first binder resin containing at least a polyester resin in a range of 5.0 to 30% by mass, an aqueous solvent, and the like, A step of applying a plurality of units (5 units or more) to a base material by a wet coating method using a metal oxide particle, a second binder resin, and a coating solution for a high refractive index layer containing an aqueous solvent, And a step of drying the substrate on which the liquid has been applied.

  Specifically, it is preferable to form an optical reflection layer laminate by alternately applying and drying a high refractive index layer and a low refractive index layer. Specifically, the following forms are mentioned.

(1) A high refractive index layer coating solution is applied and dried on a substrate to form a high refractive index layer, and then a low refractive index layer coating solution is applied and dried on the low refractive index layer. (2) A low refractive index layer coating solution is applied and dried on a substrate to form a low refractive index layer, and then a high refractive index layer coating thereon. A method of forming a high refractive index layer by applying and drying a liquid to form an optical reflective film. (3) On a substrate, a coating liquid for a high refractive index layer and a coating liquid for a low refractive index layer are alternately formed. A method of forming an optical reflective film including a high refractive index layer and a low refractive index layer by sequentially applying multiple layers and then drying (4) A coating solution for a high refractive index layer and a coating for a low refractive index layer on a substrate Examples thereof include a method of forming an optical reflective film including a high refractive index layer and a low refractive index layer by alternately applying and drying a liquid and a multilayer simultaneously. Especially, the manufacturing method as described in said (4) term used as a simpler manufacturing process is preferable. Further, in the case of simultaneous multi-layer coating, interfacial mixing is more likely to occur. Therefore, when simultaneous multi-layer coating is performed according to the present invention, the effect is more easily exhibited.

  The details described in paragraphs (0138) to (0156) of JP2013-148849A are described in detail for the preparation method, coating conditions, drying method, and the like of the coating liquid when manufacturing other optical reflective films. Can be applied.

<Optical reflector>
The optical reflective film of the present invention can be applied to a wide range of fields. For example, as a film for window pasting, such as an optical reflective film that gives an infrared shielding effect, a film for agricultural greenhouses, etc. It is mainly used for the purpose of improving weather resistance.

  The present invention provides an optical reflector in which the optical reflective film of the present invention is provided on at least one surface side of a substrate. That is, as illustrated in FIG. 3, the optical reflective film of the present invention is preferably laminated to a substrate such as glass or a glass substitute resin directly or via an adhesive to constitute a laminated glass or the like.

  Examples of the substrate applicable to the production of the optical reflector include glass, polycarbonate resin, polysulfone resin, acrylic resin, polyolefin resin, polyether resin, polyester resin, polyamide resin, polysulfide resin, unsaturated polyester resin, epoxy resin, Examples include 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 type of resin may be any of a thermoplastic resin, a thermosetting resin, and an ionizing radiation curable resin, and two or more of these may be used in combination. The substrate that can be used in the present invention can be produced by a known method such as extrusion molding, calendar molding, injection molding, hollow molding, compression molding and the like. The thickness of the substrate is not particularly limited, but is usually 0.1 mm to 5 cm.

  It is preferable that the adhesive layer or the adhesive layer that bonds the optical reflection film and the substrate is disposed on the sunlight (heat ray) incident surface side. In addition, it is preferable to sandwich the optical reflection film according to the present invention between a window glass and a substrate because it can be sealed from surrounding gas such as moisture and has excellent durability. Even if the optical reflective film according to the present invention is installed outdoors or outside a car (for external application), it is preferable because of environmental durability.

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

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

  Polyvinyl butyral resin or ethylene-vinyl acetate copolymer resin may be used. Specifically, plastic polyvinyl butyral (manufactured by Sekisui Chemical Co., Ltd., Mitsubishi Monsanto Kasei Co., Ltd.), ethylene-vinyl acetate copolymer (manufactured by DuPont, manufactured by Takeda Pharmaceutical Co., Ltd., dumiran), modified ethylene-vinyl acetate copolymer For example, Merzo G manufactured by Tosoh Corporation. In addition, you may add and mix | blend an ultraviolet absorber, an antioxidant, an antistatic agent, a heat stabilizer, a lubricant, a filler, coloring, an adhesion adjusting agent etc. suitably in a contact bonding layer.

  The heat insulation performance and solar heat shielding performance of the optical reflection film or optical reflector are generally measured according to JIS R 3209 (multilayer glass), JIS R 3106 (plate glass transmittance, reflectance, emissivity, solar heat acquisition rate). Test method), JIS R 3107 (calculation method of thermal resistance of plate glass and thermal transmissivity in architecture).

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

Example 1
<< Production of optical reflective film >>
[Preparation of optical reflection film 1]
(Preparation of coating solution 1 for forming a low refractive index layer)
The following additives were mixed at 42 ° C. to prepare a coating solution 1 for forming a low refractive index layer.

10 mass% colloidal silica dispersion (Colloidal silica: Snowtex OXS, manufactured by Nissan Chemical Industries, primary average particle size: 4-6 nm, acidic type) 350 parts 30 mass% boric acid aqueous solution 24 parts 8 mass% polyvinyl Alcohol solution (JP-45; degree of polymerization: 4500, degree of saponification: 88 mol%; manufactured by Nihon Acetate & Poval Co., Ltd.) 420 parts 20% by mass of water-soluble polyester resin (Plus Coat Z-221, manufactured by Toyo Chemical Co., Ltd.) Hydrophilic group: sodium sulfonate base, molecular weight: about 14000, complete aqueous grade) 9 parts 5% by mass of surfactant (Newcol 1305-SN; manufactured by Nippon Emulsifier Co., Ltd.) 5 parts Pure water 192 parts Low refraction prepared above The content ratio of the water-soluble polyester resin in the rate layer forming coating solution 1 is 5.0% by mass with respect to the total binder resin. The ratio F / B of the metal oxide particles (F) to the total binder resin (B) is 1.0.

(Preparation of coating solution 1 for forming a high refractive index layer)
The following additives were mixed at 42 ° C. to prepare a coating solution 1 for forming a high refractive index layer.

20 mass% silica-attached titanium dioxide sol (see below) 370 parts 1.92 mass% phosphoric acid aqueous solution 150 parts 8 mass% ethylene-modified polyvinyl alcohol (manufactured by Kuraray Co., Ltd. Exval RS-2117, degree of saponification: 97.5- 99 parts by mole) 350 parts 5% by weight surfactant aqueous solution (SOFTAZOLINE LSB-R, manufactured by Kawaken Fine Chemical Co., Ltd.)
3 parts Pure water 127 parts <Preparation of silica-attached titanium dioxide sol>
After adding 2 parts by mass of pure water to 0.5 parts by mass of 15.0% by mass of titanium oxide sol (SRD-W, volume average particle size: 5 nm, rutile titanium dioxide particles, manufactured by Sakai Chemical Industry Co., Ltd.), 90 Heated to ° C. Subsequently, 0.5 parts by mass of an aqueous silicic acid solution (sodium silicate 4 (manufactured by Nippon Chemical Industry Co., Ltd.) diluted with pure water so that the SiO ₂ concentration becomes 0.5% by mass) was gradually added. did.

Subsequently, after heat-treating at 175 ° C. for 18 hours in an autoclave and cooling, it was concentrated using an ultrafiltration membrane, and the solid content concentration was 20% by mass, and 6% by mass of SiO ₂ was adhered to the surface. A titanium dioxide sol (referred to as silica-attached titanium dioxide sol, volume average particle size: 9 nm) was prepared.

(Formation of each refractive index layer)
Using a slide hopper type coating apparatus, while maintaining the low refractive index layer coating solution 1 and the high refractive index layer coating solution 2 prepared above at 45 ° C., the substrate was heated to 45 ° C. (with a thickness of 50 μm). Polyethylene terephthalate film: Toyobo Co., Ltd., Cosmo Shine A4300) 20 layers of simultaneous multilayer coating (each refractive index layer thickness: 2.7 μm, 10 units composed of low refractive index layer and high refractive index layer) Lamination). At this time, the lowermost layer (T ₁ ) and the uppermost layer (T _n ) as shown in FIG. 1 are low refractive index layers, and other than that, the low refractive index layers and the high refractive index layers are alternately laminated. Configured. The coating amount was adjusted such that the film thickness during drying was 150 nm for each low refractive index layer and 120 nm for each high refractive index layer.

(Formation of adhesive layer)
<Preparation of adhesive layer coating solution>
An adhesive layer coating solution was prepared according to the following formulation.

Adhesive: N-2147 manufactured by Nippon Synthetic Chemical Industry (solid content 35%) 100 parts UV absorber: Tinuvin 477 (solid content 80%) manufactured by BASF Japan
2.1 parts Isocyanate-based curing agent: Coronate L55E (solid content 55%) manufactured by Tosoh Corporation 5 parts <Application of adhesive layer coating solution>
The adhesive layer coating solution was applied to a silicone surface of a separator SP-PET (brand: PET-O2-BU, manufactured by Mitsui Chemicals, Inc.) with a comma coater so that the dry film thickness was 10 μm. After drying at 0 ° C. for 1 minute, the film on which the optical reflective layer laminate is formed is supplied, and after the optical reflective layer laminate surface and the adhesive layer surface are adhered and laminated, the separator is peeled off and adhered to the optical reflective layer laminate surface. The layer was formed by transferring.

(Formation of hard coat layer)
In accordance with the following method, a hard coat layer was formed on the surface of the substrate opposite to the surface on which the optical reflective layer laminate was formed, and an optical reflective film 1 was produced.

<Preparation of hard coat layer forming coating solution HC1>
390 of Aronix (registered trademark) M-405 (mixture of dipentaerythritol pentaacrylate: dipentaerythritol hexaacrylate = 10-20: 90-80 (mass ratio), manufactured by Toagosei Co., Ltd.) as a (meth) acrylate compound. Mass parts and 0.4 parts by mass of EBECRYL (registered trademark) 350 (silicon diacrylate, manufactured by Daicel Ornex Co., Ltd.) are mixed, and a cesium-doped tungsten oxide dispersion (YMF-02A, 650 parts by mass of total solid content concentration 28% by mass, cesium doped tungsten oxide concentration 18.5% by mass, composition: Cs _0.33 WO ₃ , average particle diameter 50 nm, manufactured by Sumitomo Metal Mining Co., Ltd. 3 parts by mass of nickel chlorate hexahydrate (manufactured by Kanto Chemical Co., Ltd.) Then, 300 parts by mass of methyl ethyl ketone was added as a solvent. Furthermore, 20 parts by mass of Irgacure (registered trademark) 819 (manufactured by BASF Japan Ltd.) and 0.5 part by mass of a fluorosurfactant (phthalent (registered trademark) 650A, manufactured by Neos Co., Ltd.) are added as polymerization initiators. Thus, a coating liquid HC1 for forming a hard coat layer was prepared.

<Application of hard coat layer forming coating liquid HC1>
On the surface opposite to the surface on which the optical reflective layer laminate is formed of the film having the optical reflective layer laminate, the hard coat layer forming coating solution HC1 prepared above is dried using a gravure coater. The coating was applied under the condition that the thickness was 5 μm and dried at 90 ° C. for 1 minute. Next, the coating film is hardened by irradiating the coating film by irradiating ultraviolet rays from the surface far from the substrate of the coating film under the conditions of an illuminance of 100 mW / cm ² and an irradiation amount of 0.5 J / cm ² using an ultraviolet lamp. The layer was formed and the optical reflection film 1 was produced.

[Preparation of optical reflection films 2 to 5]
In the preparation of the coating solution 1 for forming a low refractive index layer used for the formation of the optical reflection film 1, the total binder amount is the same, and the content ratio of the plus coat Z-221, which is a water-soluble polyester resin, to the total binder amount, Except for changing to 3.0% by mass, 20.0% by mass, 29.0% by mass, and 33.0% by mass, respectively, each coating solution for forming a low refractive index layer was prepared in the same manner. Optical reflective films 2-5 were produced.

[Production of Optical Reflective Film 6]
In the preparation of the coating solution for forming a low refractive index layer used for the formation of the optical reflection film 3, in place of the plus coat Z-221 which is a water-soluble polyester resin, the same amount of plus coat Z which is the following water-soluble polyester resin. A coating solution for forming a low refractive index layer was prepared in the same manner except that -730 was used, and an optical reflective film 6 was produced using this.

Water-soluble polyester resin: Pluscoat Z-730, manufactured by Kyoyo Chemical Co., Ltd., hydrophilic group: carboxylic acid group, molecular weight: about 3000, high oxidation grade, solid content: 25% by mass
[Preparation of optical reflection film 7]
In the preparation of the coating solution for forming a low refractive index layer used for forming the optical reflective film 3, the amount of colloidal silica (silica particles) (F) added to the total amount of binder resin (B) is expressed as a ratio (F / B). A coating solution for forming a low refractive index layer was prepared in the same manner except that the value was changed to 0.3, and an optical reflective film 7 was produced using this.

[Production of Optical Reflective Films 8 to 10]
Optical reflection films 8 to 10 were produced in the same manner as in the production of the optical reflection film 7 except that F / B was changed to 0.6, 2.8, and 3.2, respectively.

[Production of Optical Reflective Film 11]
In the preparation of the coating solution for forming the low refractive index layer used for forming the optical reflection film 3, colloidal silica was changed from Snowtex OXS to Snowtex OS (manufactured by Nissan Chemical Industries, Ltd., primary average particle size: 8 to 11 nm, acidic A coating solution for forming a low refractive index layer was prepared in the same manner except that the type was changed to (type), and an optical reflective film 11 was produced using this.

[Production of Optical Reflective Film 12]
In the preparation of the coating solution for forming a low refractive index layer used for forming the optical reflective film 3, colloidal silica was changed from Snowtex OXS to Snowtex O-40 (Nissan Chemical Industries, primary average particle size: 20 to 30 nm). The coating solution for forming a low refractive index layer was prepared in the same manner except that it was changed to the acidic type), and an optical reflection film 12 was produced using this.

[Preparation of optical reflection film 13]
In the preparation of the coating solution for forming the low refractive index layer used for forming the optical reflective film 3, colloidal silica was changed from Snowtex OXS to Snowtex OL (Nissan Chemical Industries, primary average particle size: 40 to 50 nm, acidic A coating solution for forming a low refractive index layer was prepared in the same manner except that the type was changed to (type), and an optical reflection film 13 was produced using this.

[Production of Optical Reflective Films 14 to 17]
In the production of the optical reflective film 3, the same applies except that the number of stacked units composed of the low refractive index layer and the high refractive index layer is changed from 10 units to 4 units, 6 units, 19 units, and 22 units, respectively. Thus, optical reflection films 14 to 17 were produced.

[Production of Optical Reflective Film 18]
In the preparation of the coating solution for forming a low refractive index layer used for forming the optical reflection film 3, polyvinyl alcohol alone (total amount of binder resin is the same), except for plus coat Z-221 which is a water-soluble polyester resin as a binder resin. A coating solution for forming a low refractive index layer was prepared in the same manner except that the correction was made so that the optical reflection film 18 was produced.

[Preparation of optical reflection film 19]
In the production of the optical reflective film 3, the following low-refractive-index layer-forming coating solution and high-refractive-index-layer-forming coating solution described in Example 1 of JP2013-64915A are used to cause high refractive index from above the substrate. An optical reflective film 19 was produced in the same manner except that seven layers of refractive index layer / low refractive index layer / high refractive index layer / low refractive index layer / high refractive index layer / low refractive index layer / high refractive index layer were laminated. did.

(Preparation of coating solution for forming a high refractive index layer)
Titanium oxide aqueous dispersion: AERODISP (registered trademark) -W740 (manufactured by Nippon Aerosil Co., Ltd., solid content 40%) 60 parts by mass Silicone acrylic aqueous dispersion: Charine (registered trademark) FE-230N (manufactured by Nissin Chemical Industry Co., Ltd.) 120 parts by weight Gelatin: Gelatin type B derived from alkali-treated cattle (Nitta Gelatin Co., Ltd., 100% solids) 12 parts by weight Organic titanium compound: ORGATICS (registered trademark) ТC-310 (Matsumoto Fine Chemical Co., Ltd.) 3 parts by mass Pure water 485 parts by mass (Preparation of coating solution for forming a low refractive index layer)
Silicon oxide aqueous dispersion: Ludox (registered trademark) HS-40 (manufactured by DuPont, solid content 40%) 60 parts by mass Silicone acrylic water dispersion: Charine (registered trademark) FE-230N (manufactured by Nissin Chemical Industry Co., Ltd., 120 mass parts Gelatin: Gelatin type B derived from alkali-treated cattle (Nitta Gelatin Co., Ltd., solid content 100%) 12 mass parts Polyvinyl alcohol: Gohsenol (registered trademark) KL-03 (Nippon Synthetic Chemical Industry Co., Ltd.) Manufactured, 100% solid content) 12 parts by mass Pure water 596 parts by mass << Measurement and Evaluation of Characteristic Values of Optical Reflective Film >>
(Measurement of secondary average particle diameter of silica particles in the low refractive index layer)
After embedding each of the produced optical reflection films with an epoxy resin, the cross section was trimmed and exposed using a microtome, and then the cross section was scanned using a scanning electron microscope JSM-6700F manufactured by JEOL Ltd. The silica particles, which are the metal oxide particles contained in the low refractive index layer, were observed at a magnification of 10,000 times, the particle diameters of 200 secondary particles were measured, and a simple average value (number average) was obtained. The next average particle size was determined. In the measurement of the particle diameter, the secondary particle diameter of each silica particle was expressed as a diameter assuming a circle equal to the projected area.

(Measurement of visible light transmittance)
Each optical reflection film produced above was affixed to a glass substrate, and using a spectrophotometer (using an integrating sphere, manufactured by Hitachi High-Technologies Corporation, U-4100), the transmittance in a wavelength range of 380 to 750 nm was measured, The average value was determined as the visible light transmittance.

(Measurement of infrared reflectance)
Each optical reflection film produced above is affixed to a glass substrate, and using a spectrophotometer (using an integrating sphere, manufactured by Hitachi High-Technologies Corporation, U-4100), the reflectance in a wavelength range of 800 to 1300 nm is measured. The average value was obtained as the infrared reflectance.

[Evaluation of weather resistance: resistance to film peeling]
Each of the optical reflection films prepared above was attached to a glass substrate, and this sample was mounted on a sunshine weather meter (Suga Tester S80) so that the glass substrate side was the light irradiation side, 18 minutes under rain conditions, and then sunshine carbon The process of performing light irradiation with an arc for 120 minutes was defined as one cycle, and the process was continuously performed for 1000 hours (435 cycles) under these conditions.

  For each sample subjected to this forced degradation treatment, a cross cut test according to JIS K5600 (1999) was used to scratch 100 degrees with a cutter knife at an angle of 45 degrees, On top of that, cellotape (registered trademark) was strongly pressed. Subsequently, the end of the tape was peeled off at an angle of 45 degrees, the state of the grid was visually observed, and film peeling resistance after forced deterioration was evaluated according to the following criteria.

○: No peeling is observed on 100 grids. Δ: Only part around the scratched part of each grid is peeled off, but the quality is acceptable for practical use. Starting from the part, the unscratched part is also peeled off in a staircase [Water resistance evaluation: wet adhesion]
Each of the produced optical reflection films was immersed in warm water at 40 ° C. for 1 hour, and then the film state of the optical reflection layer laminate was visually observed, and water resistance was evaluated according to the following criteria.

○: No white turbidity or delamination occurs in the layer after immersion Δ: No delamination occurs after the immersion, but the edge of the component layer is slightly cloudy, but the quality acceptable for practical use X: After immersing, formation of white turbidity and delamination of the constituent layers is observed [measurement of haze]
About each produced said optical reflection film, haze was measured using the haze meter (The Nippon Denshoku Industries Co., Ltd. make, NDH2000). The light source of the haze meter was a 5V9W halogen sphere, and a silicon photocell (with a relative visibility filter) was used as the light receiving part. The haze was measured under the conditions of 23 ° C. and 55% RH.

  The results obtained as described above are shown in Table 1.

  As is clear from the results shown in Table 1, the optical reflective film that satisfies the conditions specified in the present invention has higher infrared reflectivity than the comparative example, and adhesion and water resistance after forced deterioration treatment (water immersion) It can be seen that it is excellent in the later adhesion) and has low haze characteristics.

Example 2
Each optical reflective film produced in Example 1 was used and adhered to an acrylic resin plate having a thickness of 5 mm and 20 cm × 20 cm with an acrylic adhesive to produce an optical reflector.

  As a result of measuring the visible light transmittance and infrared reflectance of the optical reflector of the present invention produced as described above, the visible light transmittance is high, the infrared reflectance and infrared shielding properties are excellent, and the film peels off even when used for a long time. It was confirmed that the optical reflector had no durability and excellent durability.

1 optical reflection film 2 substrate 3 optical reflector 4A, 4B adhesive layer 5A, 5B glass substrate ML, MLa, MLb optical reflecting layer stack U optical reflection unit _{T 1 ~T n, Ta 1 ~Ta} n, Tb 1 ~ Tb _n refractive index layer

Claims (6)

An optical reflective film having an optical reflective layer laminate in which five or more optical reflective layer units each composed of a high refractive index layer and a low refractive index layer having different refractive indexes are laminated on at least one surface side of a substrate. There,
The low refractive index layer contains two or more binder resins, at least one of the binder resins is a polyester resin, and the polyester resin is added to 5.0 to 30 of the total binder resin amount of the low refractive index layer. An optical reflection film, which is contained within a mass% range.   The optical reflection film according to claim 1, wherein the polyester resin has a sulfonic acid group at least in part.   The low refractive index layer contains metal oxide particles, and the ratio (F / B) of the mass of the metal oxide particles (F) to the total mass of the binder resin (B) is 0.5 to 3.0. The optical reflective film according to claim 1, wherein the optical reflective film is within the range of the above.   The optical reflective film according to claim 3, wherein the metal oxide particles contained in the low refractive index layer are silica particles having a secondary average particle diameter of 50 nm or less.   5. The number of stacked optical reflection layer units composed of the high refractive index layer and the low refractive index layer is in the range of 5 to 20 units. 5. The optical reflective film as described in 2.   An optical reflector comprising the optical reflective film according to any one of claims 1 to 5 on at least one surface side of a substrate.

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