WO2015198762A1

WO2015198762A1 - Optical reflective film, method for producing optical reflective film, and optical reflector using same

Info

Publication number: WO2015198762A1
Application number: PCT/JP2015/064537
Authority: WO
Inventors: 當間　恭雄
Original assignee: コニカミノルタ株式会社
Priority date: 2014-06-27
Filing date: 2015-05-20
Publication date: 2015-12-30
Also published as: JPWO2015198762A1

Abstract

　An optical reflective film having excellent weather resistance and improved adhesion of the hard coat layer is provided by means of an optical reflective film comprising a reflective part formed by molten extrusion molding and containing at least one unit obtained by laminating a high refractive index layer and a low refractive index layer, and a hard coat layer formed by applying a hard coat coating solution, wherein the residual solvent in the film falls within the range of 1 to 8mg/g.

Description

Optical reflective film, optical reflective film manufacturing method, and optical reflector using the same

The present invention relates to an optical reflection film and a method for producing the same. The present invention also relates to an optical reflector using the optical reflective film or the optical reflective film produced by the production method.

In recent years, interest in energy-saving measures has increased, and heat insulation glass with infrared shielding properties for the purpose of shielding the solar radiation energy entering the interior or interior of a building glass or vehicle glass and reducing the temperature rise and cooling load. Is adopted. Infrared shielding film that can selectively reflect infrared light and transmit visible light is usually a low refractive index layer having a relatively low refractive index and a high refractive index having a relatively high refractive index. The rate layer has a laminated structure. At this time, for the high refractive index layer and the low refractive index layer, infrared light can be selectively reflected by controlling the optical film thickness, which is the product of the refractive index and the film thickness, to cause interference.

Such an optical reflection film transmits visible light and selectively shields near infrared rays, but the reflection wavelength can be controlled only by adjusting the film thickness and refractive index of each layer. Can be reflected.

As a method for forming the refractive index layer, a method of alternately laminating two kinds of resin layers having different refractive indexes (Patent Document 1), or by applying a water-soluble polymer mixed with a metal oxide, the refractive index differs. A method of forming a near infrared reflecting layer by laminating layers (Patent Document 2) has been proposed.

An optical reflection film such as an infrared shielding film is often attached to a window glass of a building or a vehicle as described above. Therefore, for the purpose of preventing scratches on the surface during cleaning, etc., by applying actinic radiation curable resin, etc., a hard coat layer is formed on the outermost layer to improve the scratch resistance. There are many.

Japanese translation of PCT publication No. 2008-528313 (corresponding to International Publication No. 2006/074168) International Publication No. 2012/014607 (corresponding to US Patent Application Publication No. 2013/0107355)

Conventional optical reflective films, for example, have a problem that the weather resistance may not be good, for example, when haze is increased or discolored by being attached to a window glass of a building or vehicle and exposed to a high temperature and high humidity state. Was. Moreover, the adhesiveness of the hard coat layer may not be sufficient, and there is a problem that the hard coat layer may be peeled off.

Therefore, the present invention has been made in view of the above circumstances, and is an optical reflective film having excellent weather resistance and improved adhesion of the hard coat layer, a method for producing the same, and the optical reflective film or the method for producing the same. An object of the present invention is to provide an optical reflector using the optical reflective film manufactured in the above manner.

As a result of earnest research to solve the above problems, the present inventor has at least one unit obtained by laminating a high refractive index layer and a low refractive index layer, and is formed by melt extrusion molding, And the optical reflective film comprising a hard coat layer formed by application of a hard coat coating solution, wherein the residual solvent in the film is 1 to 8 mg / g, the above problems are solved. As a result, the present invention has been completed.

It is sectional drawing which represented typically the optical reflection film which concerns on one Embodiment of this invention.

The first aspect of the present invention is formed by application of a hard coat coating liquid, and a reflective portion formed by melt extrusion including at least one unit in which a high refractive index layer and a low refractive index layer are laminated. An optical reflective film comprising a hard coat layer, wherein the residual solvent in the film is 1 to 8 mg / g.

According to a second aspect of the present invention, a laminate including at least one unit in which a high refractive index layer and a low refractive index layer are laminated is formed by melt extrusion molding; at least one of the laminates is used as a hard coat coating solution. A method of producing an optical reflective film, comprising: coating on the surface side of the film to form a coating film; and drying so that a residual solvent in the laminate in which the coating film is formed is 1 to 8 mg / g. .

The third aspect of the present invention is an optical reflector in which the optical reflective film or the optical reflective film produced by the production method is provided on at least one surface of a substrate.

According to the present invention, an optical reflective film having excellent weather resistance and improved adhesion of the hard coat layer, a method for producing the same, and optical using the optical reflective film or the optical reflective film produced by the production method A reflector is provided.

The present inventor has found that when the residual solvent in the film increases, the weather resistance decreases and the adhesion of the hard coat layer decreases. Although it does not limit the technical scope of the present invention, this is because the deterioration of the material is promoted by the influence of the excessive residual solvent, and the curling of the film is caused by the gradual volatilization of the solvent. Presumed to be. Furthermore, when the residual solvent in a film was too few, it found out that workability deteriorated and adhesiveness also fell. Although it does not limit the technical scope of the present invention, it is difficult to adjust the position of the film during construction because the optical reflective film is extremely dry and the residual solvent is small, the film becomes hard and brittle. This is considered to be because folds and wrinkles are likely to occur.

Hereinafter, embodiments of the present invention will be described. In addition, this invention is not limited only to the following embodiment. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may be different from the actual ratios.

In the present specification, “X to Y” indicating a range means “X or more and Y or less”, and unless otherwise specified, measurement of operation and physical properties is room temperature (20 to 25 ° C.) / Relative humidity 40 to 50. Measured under the condition of%.

<Optical reflection film>
Hereinafter, this embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view schematically showing the optical reflective film according to the first aspect of the present invention. In the optical reflective film 10 shown in FIG. 1, light enters the hard coat layer 12 and the reflective portion 11 from the opposite side of the adhesive layer 13 as indicated by arrows.

In the optical reflection film 10, the reflection portion 11 has a unit 113 in which a low refractive index layer 111 and a high refractive index layer 112 are laminated. By laminating layers having different refractive indexes in this way, light is reflected at the boundary surface, and an optical reflection function is exhibited. In FIG. 1, three units of a low refractive index layer and a high refractive index layer are laminated in order from the light incident direction as the reflective portion 11, but the reflective portion is laminated with a low refractive index layer and a high refractive index layer. The number of low refractive index layers and the high refractive index layers and the stacking order are not particularly limited as long as at least one unit is included.

The optical reflection film 10 includes a hard coat layer 12 on the surface side where the light of the reflection portion 11 enters. Thus, by providing a hard-coat layer, the reflection part 11 can be protected from an abrasion etc. and the durability of a film can be improved. Furthermore, the optical reflective film 10 includes an adhesive layer 13 in the lowermost layer for attachment to a support base (substrate) (not shown). In addition, although the optical reflection film 10 is provided with the adhesion layer 13, in this invention, an adhesion layer is not provided but a hard-coat layer may be provided in the surface of the both sides of an optical reflection film, for example.

The total thickness of the optical reflective film of this embodiment is preferably 20 μm to 500 μm, more preferably 20 μm to 300 μm, and further preferably 30 μm to 150 μm. By setting the thickness of the optical reflection film within the above range, the residual solvent amount in the optical reflection film (also simply referred to as “film” in the present specification) can be easily adjusted by the drying step.

[Reflection part]
The optical reflective film according to one aspect of the present invention includes a reflective portion formed by melt extrusion including at least one unit in which a high refractive index layer and a low refractive index layer are laminated.

In this embodiment, the reflecting portion is formed by alternately stacking high refractive index layers and low refractive index layers having different refractive indexes. Such a refractive index difference between the low refractive index layer and the high refractive index layer exhibits a reflection function such as infrared rays and ultraviolet rays. 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 (high refractive index layer) when comparing the refractive index difference between two adjacent layers. In this specification, the refractive index layer and / or the low refractive index layer are collectively referred to as a “refractive index layer”) as a high refractive index layer, and the lower refractive index layer as a low refractive index layer. means. Therefore, whether the refractive index layer is a high refractive index layer or a low refractive index layer is a relative one determined by the relationship with the refractive index of the adjacent layer. The terms “high refractive index layer” and “low refractive index layer” mean that, in each refractive index layer constituting the optical reflection film, when the two adjacent refractive index layers are focused, each refractive index layer has the same refractive index. All forms other than the forms having the above are included.

The number of low refractive index layers and high refractive index layers (total number of refractive index layers) is not particularly limited, but is preferably 6 to 2000 (that is, 3 to 1000 units), more preferably 10 to 1500 ( That is, 5 to 750 units), more preferably 10 to 1000 (that is, 5 to 500 units). If the number of layers exceeds 2000, haze is likely to occur, and if it is less than 6, the desired reflectance may not be achieved.

In the reflective portion, 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 that the reflectance can be increased with a small number of layers. 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 0.2 or more, more preferably 0.25 or more. When the reflection part has a plurality of units of the low refractive index layer and the high refractive index layer, it is preferable that the refractive index difference between the low refractive index layer and the high refractive index layer in all the units is within the preferable range. . However, the outermost layer and the lowermost layer of the reflective portion may have a configuration outside the above preferred range.

The lower refractive index layer preferably has a lower refractive index, but generally a resin having a refractive index in the range of 1.2 to 1.6 is preferably used. The high refractive index layer preferably has a higher refractive index, but generally a resin having a refractive index in the range of 1.6 to 2.5 is preferably used.

In the optical reflective film of this embodiment, the lowermost layer and the outermost layer may be either a high refractive index layer or a low refractive index layer. However, by adopting a layer structure in which the low refractive index layer is located in the lowermost layer and the outermost layer, the adhesion to the lowermost substrate, the blowing resistance of the uppermost layer, and the application of a hard coat layer etc. to the outermost layer From the viewpoint of excellent properties and adhesion, a layer structure in which the lowermost layer and the outermost layer are low refractive index layers is preferable.

The refractive index is obtained as a difference between the high refractive index layer and the low refractive index layer according to the following method. That is, each refractive index layer is formed as a single layer (using a base material if necessary), and after cutting this sample into 10 cm × 10 cm, the refractive index is obtained according to the following method. Using a U-4000 type (manufactured by Hitachi, Ltd.) as a spectrophotometer, the surface opposite to the measurement surface (back surface) of each sample is roughened, and then light absorption is performed with a black spray. Then, the reflection of light on the back surface is prevented, and the average value is obtained by measuring 25 points of reflectance in the visible light region (400 nm to 700 nm) under the condition of regular reflection at 5 degrees, and the average refractive index is determined from the measurement result. Ask.

The reflectance in a specific wavelength region is determined by the difference in refractive index between two adjacent layers and the number of layers, and the larger the difference in refractive index, 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 reflectance of 90% or more, it can be seen that if the refractive index difference is smaller than 0.1, 200 or more layers are required. From the standpoint of improving reflectivity and reducing the number of layers, there is no upper limit to the difference in refractive index, but it is substantially about 1.4.

Since reflection at the interface between adjacent layers depends on the refractive index ratio between layers, the larger this refractive index ratio, the higher the reflectance. In addition, when the optical path difference between the reflected light on the surface of the layer and the reflected light on the bottom of the layer is a relationship expressed by n · d = wavelength / 4 when viewed as a single layer film, the reflected light is controlled to be strengthened by the phase difference. And reflectivity can be increased. Here, n is the refractive index, d is the physical film thickness of the layer, and n · d is the optical film thickness. By using this optical path difference, reflection can be controlled. Using this relationship, the refractive index and 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 film thickness of each layer, and the way 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 for increasing the reflectance. That is, if the specific wavelength region for increasing the reflectance is set to the visible light region, the visible light reflecting film is obtained, and if the specific wavelength region is set to the near infrared region, the near infrared reflecting film is obtained. Moreover, if the specific wavelength area | region which raises a reflectance is set to an ultraviolet light area | region, it will become an ultraviolet reflective film. When the optical reflective film of the present invention is used for a heat shield film, it may be a (near) infrared reflective (shield) film. In the case of an infrared reflective film, the transmittance at 550 nm in the visible light region shown in JIS R3106: 1998 is preferably 50% or more, more preferably 70% or more, and 75% or more. Further preferred. 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 unit so as to be in such a suitable range. In addition, it is preferable that the region having a wavelength of 900 nm to 1400 nm has a region with a reflectance exceeding 50%.

The infrared region of the incident spectrum of direct sunlight is related to the increase in indoor temperature, and by blocking this, the increase in indoor temperature can be suppressed. Looking at the cumulative energy ratio from the shortest infrared wavelength (760 nm) to the longest wavelength 3200 nm based on the weight coefficient described in Japanese Industrial Standard JIS R3106: 1998, the infrared from the wavelength 760 nm to the longest wavelength 3200 nm Looking at the cumulative energy from 760 nm to each wavelength when the total energy of the entire 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 efficient in energy saving effect by heat ray shielding.

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

The film thickness of each refractive index layer is preferably 80 to 400 nm, more preferably 100 to 300 nm, and still more preferably 100 to 200 nm. The thickness per layer of the refractive index layer can be adjusted by changing the width in the film thickness direction at the die extrusion port and / or by stretching conditions. The thickness of the reflecting portion is preferably 10 μm to 480 μm, more preferably 10 μm to 290 μm, and still more preferably 20 μm to 140 μm. In addition, when extending | stretching a laminated body, the said film thickness and the thickness of a reflection part show the thickness after extending | stretching.

In the present invention, the reflection portion is formed by melt extrusion molding. More specifically, for example, as described in JP-T-2002-509279 (corresponding to US Pat. No. 6,049,419), a molten resin obtained by melting a resin is ( Multi-layer) Extrude onto a casting drum from an extrusion die and then cool rapidly. At this time, the resin sheet may be stretched after extrusion cooling of the molten resin.

Unlike a method using a solvent such as a coating method or a solution pouring method, the reflective portion can be formed without using a solvent by melt extrusion molding. Thereby, the residual solvent amount in the optical reflection film can be set to 1 to 8 mg / g without analyzing and adjusting the residual solvent amount after forming the reflective portion and before forming the hard coat layer. Therefore, forming the reflective portion by melt extrusion molding is advantageous from the viewpoint of manufacturing efficiency. In the optical reflective film according to one aspect of the present invention, a reflective portion is formed by multilayer extrusion in which a high refractive index layer containing a first resin and a low refractive index layer containing a second resin are simultaneously laminated. It is preferable that

The resin contained in the refractive index layer is not particularly limited as long as it is a thermoplastic resin. As described above, the “high refractive index layer” and the “low refractive index layer” indicate that the refractive index layer having the higher refractive index is the high refractive index layer when comparing the refractive index difference between two adjacent layers. The lower refractive index layer is the low refractive index layer.

For example, as the thermoplastic resin, those described in JP-T-2002-509279 (corresponding to US Pat. No. 6,049,419) can be used. Specific examples include, for example, polyethylene naphthalate (PEN) and its isomers (eg, 2,6-, 1,4-, 1,5-, 2,7- and 2,3-PEN), polyalkylene terephthalate (Eg, polyethylene terephthalate (PET), polybutylene terephthalate, and poly-1,4-cyclohexanedimethylene terephthalate), polyimide (eg, polyacrylimide), polyetherimide, atactic polystyrene, polycarbonate, polymethacrylate (eg, Polyisobutyl methacrylate, polypropyl methacrylate, polyethyl methacrylate, and polymethyl methacrylate (PMMA)), polyacrylates (eg, polybutyl acrylate, and polymethyl acrylate), cellulose Derivatives (eg, ethyl cellulose, acetyl cellulose, cellulose propionate, acetyl cellulose butyrate, and cellulose nitrate), polyalkylene polymers (eg, polyethylene (PE), polypropylene (PP), 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 poly) Vinyl chloride), polysulfone, polyethersulfone, polyacrylonitrile, polyamide, silicone resin, epoxy resin, polyvinyl acetate, polyetheramide, Ionomeric resins, elastomers (e.g., polybutadiene, polyisoprene and neoprene), and polyurethanes. Copolymers such as copolymers of PEN (e.g. (a) terephthalic acid or esters thereof, (b) isophthalic acid or esters thereof, (c) phthalic acid or esters thereof, (d) alkane glycol, (e) cycloalkane glycol ( For example, cyclohexanedimethanoldiol), (f) alkanedicarboxylic acid, and / or (g) cycloalkanedicarboxylic acid (eg, cyclohexanedicarboxylic acid) and 2,6-, 1,4-, 1,5-, 2 , 7- and / or 2,3-naphthalenedicarboxylic acid or copolymers thereof), copolymers of polyalkylene terephthalates (eg (a) naphthalenedicarboxylic acid or esters thereof, (b) isophthalic acid or esters thereof, ( c) Phthalic acid moshi The ester thereof, (d) alkane glycol, (e) cycloalkane glycol (eg, cyclohexanedimethanol diol), (f) alkane dicarboxylic acid, and / or (g) cycloalkane dicarboxylic acid (eg, cyclohexanedicarboxylic acid) , Copolymers with terephthalic acid or esters thereof), and styrene copolymers (eg, styrene-butadiene copolymers and styrene-acrylonitrile copolymers), 4,4-bisbenzoic acid and ethylene glycol are also suitable. In addition, each layer may each include a blend of two or more of the above polymers or copolymers (eg, a blend of syndiotactic polystyrene (SPS) and atactic polystyrene). In this embodiment, as a preferable combination of the thermoplastic resins forming the high refractive index layer and the low refractive index layer, PEN / PMMA, PET / PMMA, PE / PMMA, PE / polyvinylidene fluoride, PEN / polyvinylidene fluoride, PEN / PET, PEN / polybutylene terephthalate, and the like.

The weight average molecular weight of the thermoplastic resin contained in the refractive index layer is about 10,000 to 1,000,000, 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.

The content of the thermoplastic resin in the refractive index layer is, for example, 30 to 100% by mass, preferably 50 to 100% by mass, and more preferably 70%, based on the total solid content of each refractive index layer. To 100% by mass.

(Metal oxide)
At least one of the low refractive index layer or the high refractive index layer in the optical reflective film of this embodiment may contain a metal oxide (particle). By containing metal oxide particles, the refractive index difference between the refractive index layers can be increased, and the reflection characteristics are improved. When both the low refractive index layer and the high refractive index layer contain metal oxide particles, the refractive index difference can be further increased. By including metal oxide particles, the number of stacked layers can be reduced and a thin film can be obtained. By reducing the number of layers, productivity can be improved and a decrease in transparency due to scattering at the lamination interface can be suppressed.

The average particle diameter of the metal oxide particles is, for example, 100 nm or less. When the average particle diameter of the metal oxide particles to be used is 100 nm or less, light scattering can be suppressed and the accuracy in controlling the film thickness of each refractive index layer in the optical reflection film can be improved. Here, in this specification, an average particle diameter refers to a primary average particle diameter. As used herein, the primary average particle size refers to a method of observing the particle itself using a laser diffraction scattering method, a dynamic light scattering method, or an electron microscope, and a particle image appearing on the cross section or surface of the refractive index layer. The average particle size is a value obtained by measuring the particle size of 1000 arbitrary particles by a method of observing with an electron microscope. When the metal oxide particles are coated (for example, silica-attached titanium dioxide described later), the average particle diameter of the metal oxide particles is the base (the silica-attached titanium dioxide). In this case, it means the average particle diameter of titanium dioxide before treatment).

(Metal oxide in the low refractive index layer)
Examples of the metal oxide used for the low refractive index layer include silica (silicon dioxide), and specific examples include synthetic amorphous silica and colloidal silica. Among these, acidic colloidal silica sol is preferably used, and colloidal silica dispersed in an organic solvent is more preferably used. In order to further reduce the refractive index, hollow fine particles having pores inside the particles may be used as the metal oxide particles of the low refractive index layer, and hollow fine particles of silica (silicon dioxide) are particularly preferable. Moreover, well-known metal oxide particles other than a silica can also be used. The metal oxide particles used for the low refractive index layer may be used alone or in combination of two or more.

The metal oxide particles (preferably silicon dioxide) contained in the low refractive index layer preferably have an average particle size of 3 to 100 nm. The average particle diameter of primary particles of silicon dioxide dispersed in a primary particle state (particle diameter in a dispersion state before coating) is more preferably 3 to 50 nm, and further preferably 3 to 40 nm. It is particularly preferably 3 to 20 nm, and most preferably 4 to 10 nm. Moreover, as an average particle diameter of secondary particle | grains, it is preferable from a viewpoint with few hazes and excellent visible light transmittance | permeability that it is 30 nm or less.

The colloidal silica used in the present embodiment is obtained by heating and aging a silica sol obtained by metathesis with an acid of sodium silicate or the like and passing through an ion exchange resin layer. For example, JP-A-57-14091, JP-A-60-219083 and the like.

Such colloidal silica may be a synthetic product or a commercially available product. As a commercially available product, Snowtex (registered trademark) series sold by Nissan Chemical Industries, Ltd. (Snowtex (registered trademark) OS, OXS, S, OS, 20, 30, 40, O, N, C, etc.) Is mentioned.

The surface of the colloidal silica may be cation-modified, or may be treated with Al, Ca, Mg, Ba or the like.

Moreover, hollow particles can also be used as the metal oxide particles of the low refractive index layer. When hollow fine particles are used, the average particle pore size is preferably 3 to 70 nm, more preferably 5 to 50 nm, and even more preferably 5 to 45 nm. The average particle pore size of the hollow fine particles is an average value of the inner diameters of the hollow fine particles. If the average particle pore diameter of the hollow fine particles is within the above range, the refractive index of the low refractive index layer is sufficiently lowered. The average particle diameter is 50 or more at random, which can be observed as an ellipse in a circular, elliptical or substantially circular shape by electron microscope observation, and obtains the pore diameter of each particle. Is obtained. The average particle hole diameter means the minimum distance among the distances between the two parallel lines that surround the outer edge of the hole diameter that can be observed as a circle, an ellipse, or a substantially circle or ellipse.

The content of the metal oxide particles in the low refractive index layer is, for example, 20 to 70% by mass and preferably 30 to 50% by mass with respect to the solid content of the low refractive index layer.

(Metal oxide in the high refractive index layer)
Examples of the metal oxide particles used in the high refractive index layer include titanium dioxide, zirconium oxide, zinc oxide, alumina, colloidal alumina, lead titanate, red lead, yellow lead, zinc yellow, chromium oxide, ferric oxide, Examples thereof include iron black, copper oxide, magnesium oxide, magnesium hydroxide, strontium titanate, yttrium oxide, niobium oxide, europium oxide, lanthanum oxide, zircon, and tin oxide. Among these, titanium dioxide, zirconium oxide, and the like that can form a transparent and higher refractive index layer are preferable, and rutile (tetragonal) titanium oxide particles are particularly preferable as titanium dioxide. The metal oxide particles used for the high refractive index layer may be used singly or in combination of two or more.

The primary average particle diameter of the metal oxide particles used for the metal oxide particles used in the high refractive index layer is preferably 30 nm or less, more preferably 1 to 30 nm, and more preferably 5 to 15 nm. Further preferred. A primary average particle diameter of 1 nm or more and 30 nm or less is preferable from the viewpoint of low haze and excellent visible light transmittance.

In general, titanium oxide particles are often used in a surface-treated state for the purpose of suppressing the photocatalytic activity of the particle surface and improving dispersibility in a solvent, etc. Silica, alumina, aluminum hydroxide, zirconia, and the like are preferably treated with one or more of them. More specifically, the surface of the titanium oxide particle is covered with a coating layer made of silica, and the surface of the particle is negatively charged, or the surface is positively charged at a pH of 8 to 10 where a coating layer made of aluminum oxide is formed. The one that bears is known.

Particles having a core-shell structure in which titanium oxide particles are coated with a silicon-containing hydrated oxide may be used. Here, the “coating” means a state in which a silicon-containing hydrated oxide is attached to at least a part of the surface of the titanium oxide particles. That is, the surface of the titanium oxide particles used as the metal oxide particles may be completely covered with a silicon-containing hydrated oxide, and a part of the surface of the titanium oxide particles is a silicon-containing hydrated oxide. It may be coated. From the viewpoint that the refractive index of the coated titanium oxide particles is controlled by the coating amount of the silicon-containing hydrated oxide, it is preferable that a part of the surface of the titanium oxide particles is coated with the silicon-containing hydrated oxide. . Hereinafter, such coated titanium oxide particles are also referred to as “silica-attached titanium dioxide sol”.

The titanium oxide of the titanium oxide particles coated with the silicon-containing hydrated oxide may be a rutile type or an anatase type, but a rutile type is more preferable. This is because rutile-type titanium oxide particles have lower photocatalytic activity than anatase-type titanium oxide particles, which increases the weather resistance of the high refractive index layer and the adjacent low refractive index layer, and further increases the refractive index. is there.

The term “silicon-containing hydrated oxide” in the present specification may be any of a hydrate of an inorganic silicon compound, a hydrolyzate and / or a condensate of an organosilicon compound. More preferably has a silanol group.

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

As a method of coating the titanium oxide particles with a silicon-containing hydrated oxide, it can be produced by a conventionally known method. For example, JP-A-10-158015, JP-A-2000-204301, JP-A-2007 Reference can be made to the matters described in Japanese Patent No. 246351.

Furthermore, the titanium oxide particles are preferably monodispersed. The monodispersion here means that the monodispersity obtained by the following formula is 40% or less. The particles are more preferably 30% or less, and particularly preferably 0.1 to 20%.

The content of the metal oxide particles in the high refractive index layer is, for example, 20 to 70% by mass and preferably 30 to 50% by mass with respect to the solid content of the high refractive index layer.

(Other additives)
In addition to the above, each refractive index layer includes, for example, ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988, and JP-A-62-261476, and JP-A-57-74192. JP-A-57-87989, JP-A-60-72785, JP-A-61465991, JP-A-1-95091 and JP-A-3-13376, etc. No. 42993, 59-52689, 62-280069, 61-242871, and JP-A 4-219266, etc., optical brighteners, sulfuric acid, phosphoric acid, acetic acid PH adjusters such as citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate, antifoaming agents, lubricants such as diethylene glycol, preservatives, antistatic agents, Various known additives such as DOO agent may contain. The content of these additives is 0.1 to 10% by mass with respect to the solid content of the refractive index layer.

Of these additives, when a commercially available preparation is used, the preparation may contain a solvent. However, the amount of these additives added is small compared to the amount of thermoplastic resin in the refractive index layer, and most (or completely) evaporates due to exposure to high temperatures in the melt extrusion process. Accordingly, the amount of the solvent derived from the additive preparation remaining in the optical reflection film is very small (or not detected) compared to the amount of the solvent derived from the hard coat coating solution. Therefore, with the above content, after forming the reflective portion by melt extrusion, the film can be easily contained in the film only by the drying process after the hard coat layer is formed without adjusting the residual solvent amount before the formation of the hard coat layer. The amount of residual solvent can be adjusted.

[Hard coat layer]
Some optical reflection films generally include a hard coat layer formed by a dry film formation method such as a vacuum deposition method. However, the optical reflective film of this embodiment has a hard coat layer formed by applying a hard coat coating solution. In the present specification, the “hard coat layer” is a layer having a pencil hardness of H or more according to JIS K 5600-5-4: 1999. The hard coat layer functions as a surface protective layer for enhancing the scratch resistance of the optical reflective film.

The hard coat layer according to the optical reflection film of the present embodiment may be formed only on one surface of the optical reflection film, or may be formed on both surfaces. Further, the hard coat layer may be a single layer or two or more layers. When the optical reflective film has two or more hard coat layers, the configuration of each hard coat layer may be the same or different.

Examples of the hard coat material constituting the hard coat layer include an active energy ray-curable resin such as an acrylate resin, and an inorganic material typified by a polysiloxane type. A curable resin is preferred. Such curable resins can be used singly or in combination of two or more.

The amount of the hard coat material in the hard coat layer is, for example, 20 to 99.9% by mass, preferably 20 to 80% by mass, and preferably 30 to 60% by mass with respect to the solid content of the hard coat layer. More preferably. The hard coat layer contains about 1 to 8 mg / g of solvent.

In this embodiment, the hard coat layer is formed by applying a hard coat coating solution containing a hard coat material and an optional surfactant, infrared absorber, ultraviolet absorber and / or antioxidant to the wire bar or the like. A method of forming a film by coating on the reflective portion is employed. The hard coat layer may be provided directly on the reflective part, but the conductive layer, antistatic layer, gas barrier layer, easy adhesion layer (adhesive layer), antifouling layer, Odor layer, droplet layer, slippery layer, hard coat layer, wear-resistant layer, antireflection layer, electromagnetic wave shielding layer, ultraviolet absorption layer, infrared absorption layer, printing layer, fluorescent light emitting layer, hologram layer, release layer, adhesive When including functional layers such as layers, adhesive layers, infrared cut layers (metal layers, liquid crystal layers), and colored layers (visible light absorbing layers) other than the high refractive index layer and low refractive index layer of the present invention, these layers It may be placed on top.

The solvent used for forming the hard coat layer by a coating method is not particularly limited, and examples thereof include hydrocarbons (for example, toluene, xylene, cyclohexane, etc.), alcohols (for example, methanol, ethanol, isopropanol, butanol, cyclohexane). Hexanol, etc.), ketones (eg, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, 4-hydroxy-4-methyl-2-pentanone, etc.), ethers (eg, tetrahydrofuran, etc.), glycol ethers (For example, ethylene glycol monomethyl ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve), ethylene glycol mono-n-butyl ether (butyl cellosolve), ethyl Glycol mono-tert-butyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, 3-methoxybutanol, 3-methoxy-3-methylbutanol, 3-methoxy-3-methylbutyl acetate, 1-methoxy-2- Propyl acetate, 1-ethoxy-2-propanol, 1-propoxy-2-propanol, 3-methoxybutyl acetate, ethyl 3-ethoxypropionate, propylene glycol monomethyl ether propionate, etc.), esters (for example, methyl acetate, Ethyl acetate, methyl lactate, etc.) and other organic solvents, or a mixture thereof can be used. Among these, by using a coating solution containing 5 to 20% by mass of a solvent having a relative evaporation rate of 0.1 to 0.5 based on the total amount of the solvent, the volatilization rate of the solvent in the drying process can be easily controlled. Moreover, it is preferable because the residual solvent in the film can be adjusted without excessively taking time in the drying step. That is, in one embodiment of the present invention, the hard coat layer is coated with a coating solution containing 5 to 20% by mass of the solvent having a relative evaporation rate of 0.1 to 0.5% with respect to the total amount of solvent, An optical reflection film formed by drying is provided. In this specification, the relative evaporation rate is an evaporation rate measured in accordance with ASTM-D3539-11, and is a ratio of the evaporation time of n-butyl acetate and the evaporation time of each solvent at 25 ° C. under dry air. Defined as the value of.

The solvent having a relative evaporation rate of 0.1 to 0.5 is not particularly limited. For example, 1-butanol (relative evaporation rate 0.5), diisobutyl ketone (relative evaporation rate 0.2) Cyclohexanone (relative evaporation rate 0.3), 4-hydroxy-4-methyl-2-pentanone (relative evaporation rate 0.2), ethylene glycol monoethyl ether (relative evaporation rate 0.4), ethylene glycol mono-n -Butyl ether (relative evaporation rate 0.1), ethylene glycol mono-tert-butyl ether (relative evaporation rate 0.2), ethylene glycol monomethyl ether acetate (relative evaporation rate 0.3), ethylene glycol monoethyl ether acetate (relative evaporation) 0.2), 3-methoxybutanol (relative evaporation rate 0.1), 3-methoate Cis-3-methylbutanol (relative evaporation rate 0.1), 3-methoxy-3-methylbutyl acetate (relative evaporation rate 0.1), 1-methoxy-2-propyl acetate (relative evaporation rate 0.3), 1-ethoxy-2-propanol (relative evaporation rate 0.3), 1-propoxy-2-propanol (relative evaporation rate 0.2), 3-methoxybutyl acetate (relative evaporation rate 0.1), 3-ethoxypropion Examples include ethyl acid (relative evaporation rate 0.3), propylene glycol monomethyl ether propionate (relative evaporation rate 0.2), and the like.

The coating solution used when forming the hard coat layer by a coating method contains, for example, 3 to 35% by mass of the solvent having a relative evaporation rate of 0.1 to 0.5 as described above with respect to the total amount of the solvent. The content is preferably 5 to 20% by mass. More preferably, the coating solution contains 8 to 18% by mass of a solvent having a relative evaporation rate of 0.1 to 0.5 based on the total amount of the solvent. It is also a preferred form to contain 5 to 20% by mass of a solvent having a relative evaporation rate of more than 0.1 and 0.5 or less, and a relative evaporation rate of more than 0.1 and 0.5 or less. More preferably, the solvent is contained in an amount of 8 to 18% by mass.

In the present invention, a hard coat coating solution having a relative evaporation rate of 1 to 3.5 is also preferably used. In one embodiment of the present invention, an optical reflective film formed by applying a hard coat coating solution having a relative evaporation rate of 1 to 3.5 is provided. By using such a coating liquid, it becomes easy to control the volatilization rate of the solvent in the drying step, and the residual solvent in the film can be adjusted without excessive time in the drying step. In order to set the relative evaporation rate of the coating solution within the above range, a solvent having a relative evaporation rate within the above range may be used for preparing the coating solution. The relative evaporation rate of the solvent used is adopted as a numerical value of the relative evaporation rate of the hard coat coating solution. Examples of the solvent having a relative evaporation rate of 1 to 3.5 include methyl isobutyl ketone (MIBK, relative evaporation rate 1.6), isopropanol (relative evaporation rate 1.5), and propyl acetate (relative evaporation rate 2.1). Can be illustrated. The relative evaporation rate of the coating solution is more preferably from 1.5 to 3.4, and even more preferably from 2.7 to 3.4. As a solvent having a relative evaporation rate of 1 to 3.5, a mixed solvent obtained by mixing two or more kinds of solvents may be used for the coating solution. When a mixed solvent is used as the solvent of the coating solution, the relative evaporation rate R _n of the mixed solvent can be obtained by the following equation.

In the above formula (1), i represents the name of each single solvent constituting the mixed solvent, R represents the relative evaporation rate, γ represents the activity coefficient, and φ represents the volume fraction.

When a mixed solvent in which two or more solvents are mixed as the solvent having a relative evaporation rate of 1 to 3.5 is used as the coating liquid, for example, toluene (relative evaporation rate 4.5), cyclohexane (relative evaporation rate 4) .5), methanol (relative evaporation rate 1.9), ethanol (relative evaporation rate 1.5), acetone (relative evaporation rate 5.6), methyl ethyl ketone (MEK) (relative evaporation rate 3.7), methyl isobutyl ketone (Relative evaporation rate 1.6), tetrahydrofuran (relative evaporation rate 4.9), methyl acetate (relative evaporation rate 5.1), ethyl acetate (relative evaporation rate 4.2), etc. Using a solvent having a relative evaporation rate of .5 as each single solvent constituting the mixed solvent, the volume fraction of each single solvent in which the relative evaporation rate of the mixed solvent is within the target numerical range is obtained from the above formula (1), The mixed solvent may be prepared.

The thickness of the hard coat layer is, for example, 0.5 to 20 μm, preferably 1.2 to 10 μm, and more preferably 2 to 8 μm. If the thickness of the hard coat layer is 0.5 μm or more, the scratch resistance tends to be improved, and if it is 20 μm or less, the risk of the hard coat layer being cracked by stress is reduced. Further, by setting the thickness of the hard coat layer to 1.2 to 10 μm, the balance between durability and weather resistance is good, and it can be preferably used.

(Active energy ray curable resin)
The active energy ray-curable resin refers to a resin that is cured through a crosslinking reaction or the like by irradiation with active energy rays such as ultraviolet rays and electron beams. As the active energy ray curable resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and can be cured by irradiation with an active energy ray such as an ultraviolet ray or an electron beam. Typical examples of the active energy ray curable resin include an ultraviolet curable resin and an electron beam curable resin, and an ultraviolet curable resin that is cured by irradiation with ultraviolet rays is preferable.

Examples of the ultraviolet curable resin include an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, an ultraviolet curable acrylic acrylate resin, and an ultraviolet curable epoxy resin. Etc. are preferably used. Among these, the hard coat layer is an acrylate resin selected from an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, or an ultraviolet curable acrylic acrylate resin. It is more preferable to contain.

The UV curable urethane acrylate resin generally includes 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate (hereinafter referred to as methacrylate) in addition to a product obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer. It is easily obtained by reacting an acrylate monomer having a hydroxyl group such as 2-hydroxypropyl acrylate. For example, 100 parts by mass of Unidic (registered trademark) 17-806 (manufactured by DIC Corporation) described in JP-A-59-151110 and 1 part by mass of Coronate (registered trademark) L (manufactured by Nippon Polyurethane Industry Co., Ltd.) A mixture of these is preferably used.

An ultraviolet curable polyester acrylate resin can be easily obtained by reacting a monomer such as 2-hydroxyethyl acrylate, glycidyl acrylate or acrylic acid with a hydroxyl group or carboxyl group at the end of the polyester (see, for example, Japanese Patent Laid-Open No. 59). -151112).

The ultraviolet curable epoxy acrylate resin can be obtained by reacting a terminal hydroxyl group of an epoxy resin with a monomer such as acrylic acid, acrylic acid chloride, or glycidyl acrylate.

Examples of the ultraviolet curable polyol acrylate resin include ethylene glycol (meth) acrylate, polyethylene glycol di (meth) acrylate, glycerin tri (meth) acrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate. The resin obtained by hardening 1 type (s) or 2 or more types of monomers can be mentioned.

Furthermore, as photosensitizers (radical polymerization initiators) for these resins, benzoin and its alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether; acetophenone, Acetophenones such as 2,2-dimethoxy-2-phenylacetophenone and 1-hydroxycyclohexyl phenyl ketone (trade name: Irgacure (registered trademark) 184, manufactured by BASF); methylanthraquinone, 2-ethylanthraquinone, 2-amylanthraquinone, etc. Anthraquinones; thioxanthones such as thioxanthone, 2,4-diethylthioxanthone, and 2,4-diisopropylthioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; Emissions, 4,4-bis benzophenones such as methylamino benzophenone and can be used azo compounds. These may be used alone or in combination of two or more. In addition, tertiary amines such as triethanolamine and methyldiethanolamine; photoinitiators such as benzoic acid derivatives such as 2-dimethylaminoethylbenzoic acid and ethyl 4-dimethylaminobenzoate can be used in combination. it can. The use amount of these radical polymerization initiators is preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass with respect to 100 parts by mass of the polymerizable component of the resin.

As an example of a commercial product of the active energy ray curable resin used for forming the hard coat layer, in addition to the above, for example, Unidic (registered trademark) series (DIC Corporation) (for example, Unidic (registered trademark) V) -4018, Unidic (registered trademark) V-4025, Unidic (registered trademark) 17-806, Unidic (registered trademark) 17-824-9), Hitaroid (registered trademark) series (manufactured by Hitachi Chemical Co., Ltd.), Purple light (registered trademark) series (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), Beam set series (Arakawa Chemical Industry Co., Ltd.) (for example, Beam set (registered trademark) 575, Beam set (registered trademark) 577), ETERMER 2382 (ETERNAL CHEMICAL) For example).

(Polysiloxane hard coat material)
When using a polysiloxane hard coat material, the hard coat material is cured in the drying step. As a polysiloxane hard coat material applicable to the formation of the hard coat layer, a compound represented by the following general formula (1) is preferable.

In the general formula (1), R and R ₁ each independently represent a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, and m and n are m + n = 4 An integer that satisfies the relationship.

Specific compounds include tetramethoxysilane, tetraethoxysilane, tetra-iso-propoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, Tetrapentaethoxysilane, tetrapenta-iso-propoxysilane, tetrapenta-n-propoxysilane, tetrapenta-n-butoxysilane, tetrapenta-sec-butoxysilane, tetrapenta-tert-butoxysilane, methyltriethoxysilane, methyltripropoxysilane, Methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethylethoxysilane, dimethylmethoxysilane, dimethylpropoxysilane, dimethylbutoxy Orchids, dimethyldimethoxysilane, dimethyldiethoxysilane, hexyl trimethoxysilane. Γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N-β- ( N-aminobenzylaminoethyl) -γ-aminopropylmethoxysilane / hydrochloride, γ-glycidoxypropyltrimethoxysilane, aminosilane, methylmethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloro Mention may be made of propyltrilimethoxysilane, hexamethyldisilazane, vinyltris (β-methoxyethoxy) silane, octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium chloride. Those having a hydrolyzable group such as methoxy group or ethoxy group substituted with a hydroxy group are generally referred to as polyorganosiloxane hard coat materials.

Specific examples of the polyorganosiloxane-based hard coat material include Surcoat Series, BP-16N (manufactured by Doken Co., Ltd.), SR2441 (manufactured by Toray Dow Corning Co., Ltd.), Perma-New 6000 (California Hard Coating Company, Inc.) Can be used.

The hard coat layer preferably contains the following surfactant, infrared absorber, ultraviolet absorber and / or antioxidant.

(Surfactant)
In the optical reflective film of this embodiment, the hard coat layer preferably contains a surfactant. When a coating film is formed with a hard coat coating solution containing a surfactant, it becomes a highly leveled coating film. It can be expected that the adhesion of the coat layer is improved.

The type of the surfactant is not particularly limited, and a fluorosurfactant, an acrylic surfactant, a silicone surfactant, and the like can be used. In particular, a fluorosurfactant is preferably used from the viewpoint of leveling properties, water repellency, and slipperiness of the coating solution.

Examples of the fluorosurfactant include, for example, Megafac (registered trademark) F series (F-430, F-477, F-552 to F-559, F-561, F-562, etc., manufactured by DIC Corporation. ), Megafuck (registered trademark) RS series (RS-76-E, etc.) manufactured by DIC Corporation, Surflon (registered trademark) series manufactured by AGC Seimi Chemical Co., Ltd., POLYFOX series manufactured by OMNOVA SOLUTIONS Corporation, T & K TOKA Corporation Commercially available products such as ZX series, OPTOOL (registered trademark) series manufactured by Daikin Industries, Ltd., and Footent (registered trademark) series (602A, 650A, etc.) manufactured by Neos Co., Ltd. can be used. Examples of the acrylic surfactant include Polyflow series (manufactured by Kyoeisha Chemical Co., Ltd.), New Coal series (manufactured by Nippon Emulsifier Co., Ltd.), and BYK (registered trademark) -354 (manufactured by Big Chemie Japan Co., Ltd.). Examples of the silicone-based surfactant include BYK (registered trademark) -345, BYK (registered trademark) -347, BYK (registered trademark) -348, and BYK (registered trademark) -349 (manufactured by Big Chemie Japan). Surfactants may be used alone or in admixture of two or more.

The amount of the surfactant in the hard coat layer can be adjusted by changing the blending amount of the surfactant in the hard coat coating solution, and the mass of the surfactant per dry mass of the hard coat layer is 0.01-5. It is preferable that it is mass%.

(Infrared absorber)
In the optical reflective film of this embodiment, the hard coat layer preferably contains an infrared absorber. When the hard coat layer contains an infrared absorber, an increase in haze and discoloration when exposed to a high temperature and high humidity state can be suppressed.

As the infrared absorber applicable to the hard coat layer, both inorganic infrared absorbers and organic infrared absorbers can be used, but inorganic infrared absorbers are preferable, visible light transmittance, infrared absorptivity. From the viewpoint of suitability for dispersion in the resin, the hard coat layer more preferably contains a tin oxide infrared absorber.

For example, inorganic infrared absorbers include zinc oxide, antimony-doped zinc oxide (AZO), indium-doped zinc oxide (IZO), gallium-doped zinc oxide (GZO), aluminum-doped zinc oxide, tin oxide, antimony-doped tin oxide ( ATO), indium-doped tin oxide (ITO), zinc antimonate, lanthanum boride, nickel complex compounds can be used, among which antimony-doped zinc oxide, antimony-doped tin oxide (ATO), indium-doped tin oxide Or zinc antimonate is preferable. As the organic infrared absorber, for example, an imonium compound, a phthalocyanine compound, or an aminium compound can be used. These infrared absorbers can be used alone or in combination of two or more.

As the infrared absorber, a synthetic product or a commercially available product may be used. Examples of commercially available products include, for example, Cellux (registered trademark) series (manufactured by Nissan Chemical Industries, Ltd.) and passette series (manufactured by Hakusuitec Co., Ltd.) as zinc oxide, SR35M, TRB Paste (and above) as tin oxide Advanced Nano Products), ATO dispersion, ITO dispersion (Mitsubishi Materials Co., Ltd.), KH series (Sumitomo Metal Mining Co., Ltd.) and the like. Examples of the organic commercial products include NIR-IM1, NIR-AM1 (manufactured by Nagase Chemitex Co., Ltd.), Lumogen (registered trademark) series (manufactured by BASF Corp.), and the like. Infrared absorbers may be used alone or in admixture of two or more.

The content of the infrared absorber in the hard coat layer is preferably 5% by mass to 80% by mass, and more preferably 30% by mass to 70% by mass, based on the dry mass of the hard coat layer.

Further, the hard coat layer may contain inorganic fine particles other than the infrared absorber. Preferable inorganic fine particles include fine particles of an inorganic compound containing a metal such as titanium, silica, zirconium, aluminum, magnesium, antimony, zinc or tin. The average particle size of the inorganic fine particles is preferably 1000 nm or less, and more preferably in the range of 10 to 500 nm, from the viewpoint of ensuring visible light transmittance. In addition, since inorganic fine particles have a higher bonding strength with the curable resin forming the hard coat layer, they can be prevented from falling out of the hard coat layer, so that a photopolymerization reactivity such as monofunctional or polyfunctional acrylate is present. Those having a functional group introduced on the surface are preferred.

(UV absorber)
In the optical reflective film of this embodiment, the hard coat layer may contain an ultraviolet absorber.

Examples of the ultraviolet absorber include benzophenone ultraviolet absorbers such as 2,4-dihydroxy-benzophenone and 2-hydroxy-4-methoxy-benzophenone; 2- (2′-hydroxy-5-methylphenyl) benzotriazole, 2 -Benzotriazole-based ultraviolet absorbers such as (2'-hydroxy-3 ', 5'-di-t-butylphenyl) benzotriazole; phenyl salicylate, 2-4-di-t-butylphenyl-3,5 -Phenyl salicylate UV absorbers such as di-t-butyl-4-hydroxybenzoate; hindered amine UV absorbers such as bis (2,2,6,6-tetramethylpiperidin-4-yl) sebacate; 2,4 -Diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine, 2,4 Triazine-based UV absorbers such as diphenyl-6- (2-hydroxy-4-ethoxyphenyl) -1,3,5-triazine; and the like.

In addition to the above, the ultraviolet absorber includes a compound having a function of converting the energy held by ultraviolet rays into vibrational energy in the molecule and releasing the vibrational energy as thermal energy.

In addition, you may use an ultraviolet absorber individually or in mixture of 2 or more types. Moreover, as the ultraviolet absorber, a synthetic product or a commercially available product may be used. Examples of commercially available products include, for example, Tinuvin (registered trademark) 320, Tinuvin (registered trademark) 328, Tinuvin (registered trademark) 234, Tinuvin (registered trademark) 1577, Tinuvin (registered trademark) 622 (above, BASF Japan Ltd.) Adekastab (registered trademark) LA-31 (manufactured by Adeka Co., Ltd.), SEESORB (registered trademark) 102, SEESORB (registered trademark) 103, SEESORB (registered trademark) 501 (manufactured by Sipro Kasei Corporation) Is mentioned.

The content of the ultraviolet absorber is preferably 0.1% by mass or more and 10% by mass or less, and preferably 0.1% by mass or more and 5% by mass or less with respect to the total mass of the hard coat layer.

(Antioxidant)
In the optical reflective film of this embodiment, the hard coat layer may contain an antioxidant. Antioxidants include 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane and 2,2′-methylenebis (4-ethyl-6-tert-butylphenol) , Tetrakis- [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] phenolic antioxidants such as methane; distearyl-3,3′-thiodipropionate Thiol antioxidants such as pentaerythritol-tetrakis- (β-lauryl-thiopropionate); tris (2,4-di-t-butylphenyl) phosphite, distearyl pentaerythritol diphosphite, di ( Phosphite antioxidants such as 2,6-di-t-butylphenyl) pentaerythritol diphosphite; bis (2,2,6,6-teto Hindered amine antioxidants such as lamethyl-4-piperidyl) sebacate and bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate;

In addition, you may use antioxidant alone or in mixture of 2 or more types. As the antioxidant, a synthetic product or a commercially available product may be used. Examples of commercially available products include, for example, NOCRACK (registered trademark) series (manufactured by Ouchi Shinsei Chemical Co., Ltd.), ADK STAB (registered trademark) series (manufactured by ADEKA Corporation), IRGANOX (registered trademark) series, IRGAFOS ( (Registered trademark) series (all of which are manufactured by Ciba Specialty Chemicals) and Sumilizer (registered trademark) series (which are manufactured by Sumitomo Chemical Co., Ltd.).

The content of the antioxidant is preferably 0.1% by mass or more and 10% by mass or less, and preferably 0.1% by mass or more and 5% by mass or less with respect to the total mass of the hard coat layer.

Also, the hue can be adjusted by adding dyes or pigments to the hard coat layer. For example, cadmium red, molybdenum red, chromium permillion, chromium oxide, viridian, titanium cobalt green, cobalt green, cobalt chrome green, Victoria green, ultramarine blue, ultramarine blue, bitumen, Berlin blue, miloli blue, cobalt blue, cerulean blue, Colored inorganic pigments such as cobalt silica blue, cobalt zinc blue, manganese violet, mineral violet, and cobalt violet, organic pigments such as phthalocyanine pigments, and anthraquinone dyes are preferably used.

[Other layers]
The optical reflection film of this embodiment is provided with a conductive layer, an antistatic layer, a gas barrier layer, an easy adhesion layer (adhesive layer), an antifouling layer, a deodorizing layer, a droplet layer, and an easy slip layer for the purpose of adding further functions. 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, high refractive index layer of the present invention and low You may have 1 or more of functional layers, such as reflection layers (metal layer, liquid crystal layer) other than a refractive index layer, and a colored layer (visible light absorption layer).

These functional layers are, for example, coating methods other than dry deposition methods such as sputtering (DC sputtering, RF sputtering, ion beam sputtering, magnetron sputtering, etc.), vacuum deposition, and ion plating. However, it is preferably formed by a dry film forming method that does not use a solvent. Even when these functional layers are formed by a coating method, if the drying step is performed after measuring the residual solvent amount, the residual solvent amount in the film is adjusted by means such as measuring the weight change during the drying step. can do. In addition, when these functional layers are formed by a coating method, from the viewpoint of easy adjustment of the residual solvent amount, the solvents described above as being preferably used in the formation of the hard coat layer, particularly 0.1 to It is preferable to use a coating solution in which the solvent having a relative evaporation rate of 0.5 is 5 to 20% by mass with respect to the total amount of the solvent in consideration of compatibility with the material used for the functional layer. A solvent having a relative evaporation rate of 1 to 3.5 can also be preferably used.

The stacking order of the above-mentioned various functional layers in the reflective film is not particularly limited.

[Residual solvent]
The optical reflective film of this embodiment is characterized in that the residual solvent in the optical reflective film is 1 to 8 mg / g. The residual solvent in the optical reflection film may be 1 to 8 mg / g, preferably 1 to 5 mg / g, more preferably 1 to 3.6 mg / g, and still more preferably 1 to 3 mg / g. g. When the residual solvent in the optical reflection film is less than 1 mg / g, the influence of the shrinkage of the hard coat layer is increased, and a decrease in adhesion due to curling and cracking and a deterioration in haze are observed. Moreover, when the residual solvent in an optical reflection film exceeds 8 mg / g, it will become easy to raise | generate a haze and discoloration when exposed to a high-temperature, high-humidity state, and the adhesiveness of a hard-coat layer will fall.

In the optical reflection film of this embodiment, the reflection portion is formed by melt extrusion molding. Therefore, it is not necessary to use a solvent in the formation process of the reflection part. Alternatively, even if a small amount of solvent derived from the additive is used, the solvent evaporates in the melt extrusion process. On the other hand, since the hard coat layer included in the optical reflective film of this embodiment is formed by applying a hard coat coating solution, a solvent is used in the coating formation process of the hard coat layer. The amount of residual solvent in the film is determined by controlling the drying conditions (drying temperature, drying time, etc.) in the drying process performed after the coating film forming process, and the solvent used for the film thickness of the hard coat film and the coating film forming process. It can be arbitrarily adjusted by selecting. For example, by increasing the drying temperature or extending the drying time, the amount of residual solvent in the film decreases. On the other hand, the residual solvent amount in the film increases by lowering the drying temperature or shortening the drying time. In addition, when compared at a constant drying temperature and drying time, if the thickness of the hard coat coating film is reduced or a solvent with a high relative evaporation rate is used in the preparation of the hard coat coating solution, the amount of residual solvent decreases. . On the other hand, when the thickness of the hard coat coating film is increased or a solvent having a low relative evaporation rate is used, the amount of residual solvent increases. The amount of residual solvent in the film can be arbitrarily set by a method such as measuring the amount of residual solvent in the film before drying by the following method and then performing drying while observing a change in the weight of the film.

The amount of residual solvent in the film can be measured by gas chromatography. Specifically, a piece of film cut out perpendicular to the film thickness direction is weighed, sealed in a vial, and heated by an oven at 120 ° C. for 30 minutes, and the generated gas is measured by gas chromatography under the following measurement conditions. To do.

(Gas chromatography measurement conditions)
GC: Column G & W Scientific DB-624 (0.25 mm ID × 30M)
OVEN 40 ℃ (2min) -10 ℃ / min-230 ℃ (14min)
INJ 230 ℃
AUX 230 ℃
MASS scan MassRange 20-300.

<Method for producing optical reflection film>
In the second aspect of the present invention, a laminate including at least one unit in which a high refractive index layer and a low refractive index layer are laminated is formed by melt extrusion molding (reflecting portion forming step); hard coat coating solution Is applied to at least one surface of the laminate to form a coating film (coating film forming step); and dried so that the residual solvent in the laminate having the coating film is 1 to 8 mg / g The manufacturing method of the optical reflection film including doing (drying process) is provided.

In the second aspect of the present invention, a laminate including at least one unit in which a high refractive index layer and a low refractive index layer are laminated is formed by melt extrusion molding. In addition, the laminated body formed by melt extrusion molding is corresponded in the reflection part in an optical reflection film. Unlike the method of forming a reflective part using a solvent such as the coating method or the solution pouring method, optical reflection without using a solvent is achieved by using a laminate of a thermoplastic resin obtained by melt extrusion molding as a reflective part. A reflective portion of the film can be formed. Also, by adopting melt extrusion molding, even if a solvent is contained in the additive used in the reflective part forming step, most (or all) of the additive is evaporated in the melt extrusion process exposed to high temperature, and the lamination is performed. The amount of solvent remaining in the body is very small (or substantially free). Therefore, it is easy to adjust the amount of residual solvent in the film that is the final product without adjusting the amount of residual solvent before the formation of the hard coat coating film, which is advantageous from the viewpoint of production efficiency.

In the method for producing an optical reflective film according to this aspect, a high refractive index layer containing a first thermoplastic resin and a low refractive index layer containing a second thermoplastic resin are laminated simultaneously, and laminated by multilayer extrusion. It is preferable to form a body (reflection part).

In the second aspect of the present invention, each refractive index layer material is melted at 100 to 400 ° C. so as to have an appropriate viscosity for extrusion, and an additive such as a metal oxide is added as necessary to increase the refractive index. The thermoplastic resin of both the first resin contained in the refractive index layer and the second resin contained in the low refractive index layer can be extruded by an extruder so as to form two layers alternately.

Before the melting, it is preferable to mix the thermoplastic resin and other additives that are added as necessary with a mixer or the like. Alternatively, the mixture may be directly melted to form a film using an extruder, but once the mixture is pelletized, the pellet may be melted with an extruder to form a film.

As the extruder, various extruders available on the market can be used, but a melt-kneading extruder is preferable, and a single-screw extruder or a twin-screw extruder may be used.

In addition, when forming a film directly without producing pellets from the mixture, it is preferable to use a twin screw extruder because an appropriate degree of kneading is necessary, but even with a single screw extruder, the screw shape is a Maddock type. By changing to a kneading type screw such as unimelt or dull mage, moderate kneading can be obtained, so that it can be used. Moreover, when using a pellet, a single screw extruder or a twin screw extruder can be used.

Further, at the time of kneading, it is preferable to lower the oxygen concentration by replacing with an inert gas such as nitrogen gas or reducing the pressure.

Next, the extruded laminated film is cooled and solidified by a cooling drum or the like to obtain a laminated body (reflecting portion in the optical reflecting film).

Thereafter, the laminate may optionally be heated and then stretched in two directions. As a stretching method, the unstretched laminate obtained by peeling from the cooling drum described above is subjected to a glass transition temperature (Tg) of −50 ° C. to Tg + 100 ° C. through a plurality of roll groups and / or a heating device such as an infrared heater. It is preferable to heat within the range and perform one-stage or multistage longitudinal stretching in the laminate transport direction (also referred to as the longitudinal direction). Next, it is also preferable to stretch the stretched laminate obtained as described above in a direction (also referred to as a width direction) orthogonal to the laminate transport direction. In order to stretch the laminate in the width direction, it is preferable to use a tenter device.

When stretching in the laminate transport direction or the direction perpendicular to the laminate transport direction, it is preferably stretched at a magnification of 1.5 to 5.0 times, more preferably in the range of 2.0 to 4.0 times. is there. In addition, the frequency | count of extending | stretching may be 1 time and may be 2 times or more.

Also, it can be heat-fixed following stretching. The heat setting is preferably carried out in the range of Tg-100 ° C. to Tg + 50 ° C., usually for 0.5 to 300 seconds. The heat fixing means is not particularly limited and can be generally performed with hot air, infrared rays, a heating roll, microwaves, or the like, but is preferably performed with hot air in terms of simplicity. It is preferable to increase the heating of the laminated body stepwise.

The heat-fixed laminate is usually cooled to Tg or less, and the clip gripping portions at both ends of the laminate are cut and wound. In addition, it is preferable that the cooling is gradually performed from the final heat setting temperature to Tg at a cooling rate of 100 ° C. or less per second. The means for cooling is not particularly limited, and can be performed by a conventionally known means. In particular, it is preferable to perform these treatments while sequentially cooling in a plurality of temperature ranges in terms of improving the dimensional stability of the film. The cooling rate is a value obtained by (T1−Tg) / t, where T1 is the final heat setting temperature and t is the time required for the laminate to reach Tg from the final heat setting temperature.

In the manufacturing method in this aspect, after forming another functional layer as necessary on at least one surface side of the laminate (reflecting part in the film) obtained by the above method, a hard coat coating solution is applied. Form a coating film. Examples of the coating method include coating with a wire bar, spin coating, dip coating, and the like. Further, it can be applied by a continuous coating apparatus such as a die coater, a gravure coater, or a comma coater.

The hard coat coating solution is applied so that the thickness of the hard coat layer after drying is, for example, 0.5 to 20 μm, preferably 1.2 to 10 μm, more preferably 2 to 8 μm. By repeating the application and drying steps a plurality of times, the thickness of the hard coat layer can be increased to a desired thickness. When compared at a constant drying temperature and drying time, the amount of residual solvent can be reduced by reducing the film thickness of the hard coat film, and the amount of residual solvent can be reduced by increasing the film thickness of the hard coat film. Can be increased.

The solvent of the hard coat coating solution is not particularly limited, and can be appropriately selected from the solvents exemplified in the first embodiment of the present invention such as alcohols, or can be used by mixing them. Among these, by using a coating solution containing 5 to 20% by mass of a solvent having a relative evaporation rate of 0.1 to 0.5 based on the total amount of the solvent, the volatilization rate of the solvent in the drying process can be easily controlled. In addition, the residual solvent in the film can be adjusted without excessive time in the drying step. In this specification, the relative evaporation rate is an evaporation rate measured according to ASTM-D3539-11, and is the same as that of the first embodiment. Examples of the solvent having a relative evaporation rate of 0.1 to 0.5 include 1-butanol (relative evaporation rate of 0.5) exemplified in the first embodiment.

The coating liquid used for forming the hard coat coating film contains, for example, 3 to 35% by mass of the solvent having a relative evaporation rate of 0.1 to 0.5 as described above with respect to the total amount of the solvent, Preferably, the coating solution contains 5 to 20% by mass of a solvent having a relative evaporation rate of 0.1 to 0.5 based on the total amount of the solvent. More preferably, the coating solution contains 8 to 18% by mass of a solvent having a relative evaporation rate of 0.1 to 0.5 based on the total amount of the solvent. It is also a preferred form to contain 5 to 20% by mass of a solvent having a relative evaporation rate of more than 0.1 and 0.5 or less, and a relative evaporation rate of more than 0.1 and 0.5 or less. More preferably, the solvent is contained in an amount of 8 to 18% by mass.

In the present invention, a coating solution having a relative evaporation rate of 1 to 3.5 is also preferably used. In order to set the relative evaporation rate of the coating solution within the above range, a solvent having a relative evaporation rate within the above range may be used for preparing the coating solution. The relative evaporation rate of the solvent used is adopted as a numerical value of the relative evaporation rate of the hard coat coating solution. That is, in one embodiment of the present invention, the manufacturing process of the optical reflection film includes a process of applying a hard coat coating liquid having a relative evaporation rate of 1 to 3.5. As the solvent having a relative evaporation rate of 1 to 3.5, those exemplified in the first aspect can be used. The relative evaporation rate of the coating solution is more preferably from 1.5 to 3.4, and even more preferably from 2.7 to 3.4. In this case, a mixed solvent obtained by mixing two or more solvents as described in the first aspect can also be used for the coating solution. When the relative evaporation rate of the solvent used in the production of the film is 1 to 3.5, the residual solvent amount can be easily adjusted by controlling the drying conditions. When compared at a constant drying temperature and drying time, the residual solvent amount decreases as the relative evaporation rate of the solvent used in the preparation of the hard coat coating solution increases, and the residual solvent amount increases as the relative evaporation rate decreases.

The blending amount of the above-mentioned hard coat material such as an active energy ray-curable resin or an inorganic material in the hard coat coating solution is preferably 3 to 80% by mass with respect to the entire hard coat coating solution. It is more preferably 70% by mass, and further preferably 10 to 50% by mass. The amount of solvent in the hard coat coating solution is preferably 20 to 97% by mass, more preferably 30 to 90% by mass, and 40 to 70% by mass with respect to the entire hard coat coating solution. More preferably it is.

A surfactant can be added to the hard coat coating solution to impart leveling properties, water repellency, slipperiness, and the like. There is no restriction | limiting in particular as a kind of surfactant, Said fluorine-type surfactant, acrylic surfactant, silicone type surfactant, etc. can be used. In particular, a fluorosurfactant is preferably used from the viewpoint of leveling properties, water repellency, and slipperiness. The amount of the surfactant in the hard coat coating solution is, for example, 0.004 to 2% by mass with respect to the entire hard coat coating solution. As the commercially available surfactant, those exemplified in the first aspect are adopted.

From the viewpoint of improving infrared shielding properties, the above-described infrared absorbers such as antimony-doped tin oxide (ATO) may be added. The amount of the infrared absorber in the hard coat coating solution is, for example, 2 to 40% by mass with respect to the entire hard coat coating solution. As a commercially available infrared absorber, what was illustrated by 1st embodiment is employ | adopted.

In one embodiment of the present invention, the hard coat coating solution comprises 3 to 35% by weight hard coat material, 35 to 90% by weight solvent, 0.01 to 0.5% by weight surfactant, and 5 to 34. 0.5% by mass of an infrared absorber (100% by mass in total) is contained.

The hard coat coating solution may also contain the above-described ultraviolet absorber and antioxidant. What was illustrated by the 1st side surface as a commercially available ultraviolet absorber and antioxidant is employ | adopted.

The method for producing the hard coat coating solution is not particularly limited, and it can be obtained by adding each component to a solvent and mixing appropriately. The order of addition and the addition method are not particularly limited, and each component may be added and mixed sequentially while stirring, or may be added and mixed all at once while stirring.

The prepared hard coat coating solution may be directly applied to at least one surface side of the above-mentioned laminate (reflective portion in the film), but the conductive layer and antistatic layer are provided between the hard coat layer and the reflective portion. Layer, gas barrier layer, easy adhesion layer (adhesion layer), antifouling layer, deodorant layer, droplet layer, slippery layer, hard coat layer, wear-resistant layer, antireflection layer, electromagnetic wave shielding layer, ultraviolet absorption layer, Infrared absorbing layer, printed layer, fluorescent light emitting layer, hologram layer, release layer, adhesive layer, adhesive layer, infrared cut layer (metal layer, liquid crystal layer) other than high refractive index layer and low refractive index layer of the present invention, colored layer When a functional layer such as (visible light absorbing layer) is included, it may be applied to these layers.

In order to further improve the adhesion to the lower layer of the hard coat layer, an anchor layer (primer layer) can be formed before laminating the cured resin layer. The thickness of the anchor layer is not particularly limited, but is about 0.1 to 10 μm. Preferable examples of the resin constituting the anchor layer include polyvinyl acetal resin and acrylic resin.

Thereafter, the object to be dried is dried so that the residual solvent in the laminate (the object to be dried) after forming the coating film is 1 to 8 mg / g. The drying means is not particularly limited, and warm air drying, infrared drying, and microwave drying are used. The drying temperature is appropriately set according to conditions such as the solvent used and the drying temperature, but is usually 50 to 200 ° C., preferably 70 to 150 ° C., and more preferably 80 to 120 ° C. The drying time is, for example, 30 seconds to 300 seconds, preferably more than 90 seconds and 180 seconds or less. If the drying temperature is increased and / or the drying time is increased, the amount of residual solvent in the film to be dried and the final product can be reduced. On the contrary, if the drying temperature is lowered and / or the drying time is shortened, the amount of solvent remaining in the film to be dried and the final product can be increased.

The residual solvent in the dried object may be 1 to 8 mg / g, preferably 1 to 5 mg / g, more preferably 1 to 3.6 mg / g, and still more preferably 1 to 3 mg / g. g. When the residual solvent in the object to be dried is less than 1 mg / g, the thermal contraction of the hard coat increases, cracks are likely to occur, and the adhesiveness is reduced. Moreover, when the residual solvent in a dry object exceeds 8 mg / g, it will become easy to raise | generate a haze and discoloration when exposed to a high temperature, high humidity state, and the adhesiveness of a hard-coat layer will fall.

In order to adjust the residual solvent in the object to be dried, the amount of residual solvent in the laminate after the application of the hard coat coating solution and before the drying step may be measured by the above-described method using gas chromatography. Further, in the drying process, it is easy to adjust the amount of residual solvent in the object to be dried by observing the change in weight accompanying the evaporation of the solvent over time.

After drying, the object to be dried may be cooled in order to stabilize the amount of residual solvent in the film. The cooling method is not particularly limited, and for example, a method similar to the cooling method after heat setting described above may be employed.

When an active energy ray-curable resin is used, the hard coat material may be cured by irradiating the hard coat coating film with an active energy ray (curing treatment) after the drying step. Irradiation wavelength of the active energy ray, intensity, can not be said sweepingly because changes reactivity by the light amount, for example, the illuminance is preferably 50 ~ 1500mW / cm ^2, more preferably 100 ~ 1000mW / cm ^2. At this time, the amount of irradiation energy is preferably 50 ~ 1500mJ / cm ^2, more preferably 100 ~ 1000mJ / cm ^2. The irradiation time is preferably 1 to 300 seconds. In the case of an active energy ray-curable resin, unlike the thermosetting resin, the curing conditions are gentle, and thus there is an advantage that it is not necessary to consider the influence on the residual solvent amount in the curing process. As the active energy ray, an electron beam or the like can be used in addition to ultraviolet rays depending on the active energy ray curable resin to be used.

<Optical reflector>
The optical reflective film of the present invention can be applied to a wide range of fields. That is, a preferred embodiment of the present invention is an optical reflector in which the optical reflective film or the optical reflective film produced by the production method is provided on at least one surface of a substrate. For example, film for window pasting such as heat ray reflecting film that gives heat ray reflection effect, film for agricultural greenhouses, etc. Etc., mainly for the purpose of improving the weather resistance. In particular, the optical reflective film according to the present invention is suitable for a member that 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, and phenol. Examples thereof include resins, diallyl phthalate resins, polyimide resins, urethane resins, polyvinyl acetate resins, polyvinyl alcohol resins, styrene resins, vinyl chloride resins, metal plates, and ceramics. 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 can be produced by a known method such as extrusion molding, calendar molding, injection molding, hollow molding, compression molding or 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 reflecting film and the substrate is disposed on the sunlight (heat ray) incident surface side. Further, it is preferable to sandwich the optical reflection film between the window glass and the substrate because it can be sealed from surrounding gas such as moisture and has excellent durability. Even if the infrared shielding film according to the present invention is installed outdoors or outside a car (for external application), it is preferable because of environmental durability.

The adhesive layer or adhesive layer that bonds the optical reflective film and the substrate is preferably installed so that the optical reflective film is on the sunlight (heat ray) incident surface side when bonded to a window glass or the like. Further, 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 for durability. Even if the optical reflective film of the present invention is installed outdoors or on the outside of a vehicle (for external application), it is preferable because of environmental durability.

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

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

Further, a polyvinyl butyral resin or an ethylene-vinyl acetate copolymer resin used as an intermediate layer of laminated glass may be used. Specifically, plastic polyvinyl butyral (manufactured by Sekisui Chemical Co., Ltd., Mitsubishi Monsanto, etc.), ethylene-vinyl acetate copolymer (manufactured by DuPont, Takeda Pharmaceutical Co., Ltd., duramin), modified ethylene-vinyl acetate copolymer (Mersen (registered trademark) G manufactured by Tosoh Corporation). In addition, you may mix | blend suitably an ultraviolet absorber, an antioxidant, an antistatic agent, a heat stabilizer, a lubricant, a filler, coloring, an adhesion regulator, etc. in an adhesion layer or an adhesion layer.

The heat insulation performance and solar heat shielding performance of an optical reflective film or optical reflector (infrared shield) are generally JIS R 3209 (1998) (multi-layer glass), JIS R 3106 (1998) (transmittance of sheet glass) -Test method of reflectance, emissivity, and solar heat acquisition rate), JIS R 3107 (1998) (calculation method of thermal resistance of plate glass and heat transmissivity in architecture).

Measure solar transmittance, solar reflectance, emissivity, and visible light transmittance. (1) Using a spectrophotometer with a wavelength (300 to 2500 nm), measure the spectral transmittance and spectral reflectance of various single glass plates. The emissivity is measured using a spectrophotometer having a wavelength of 5.5 to 50 μm. In addition, a predetermined value is used for the emissivity of float plate glass, polished plate glass, mold plate glass, and heat ray absorbing plate glass. (2) The solar transmittance, solar reflectance, solar absorption rate, and corrected emissivity are calculated according to JIS R 3106 (1998) by calculating the solar transmittance, solar reflectance, solar absorption rate, and vertical emissivity. The corrected emissivity is obtained by multiplying the vertical emissivity by the coefficient shown in JIS R 3107 (1998). The heat insulation and solar heat shielding properties are calculated by (1) calculating the thermal resistance of the multilayer glass according to JIS R 3209 (1998) using the measured thickness value and the corrected emissivity. However, when the hollow layer exceeds 2 mm, the gas thermal conductance of the hollow layer is determined according to JIS R 3107 (1998). (2) The heat insulation is obtained by adding a heat transfer resistance to the heat resistance of the double-glazed glass and calculating the heat flow resistance. (3) The solar heat shielding property is calculated by calculating the solar heat acquisition rate according to JIS R 3106 (1998) and subtracting it from 1.

<Embodiment>
Hereinafter, embodiments of the present invention will be exemplarily shown.
(1) Including at least one unit in which a high refractive index layer and a low refractive index layer are laminated, a reflective portion formed by melt extrusion, and a hard coat layer formed by applying a hard coat coating solution An optical reflective film, wherein the residual solvent in the film is 1 to 8 mg / g.
(2) The optical reflective film according to (1), wherein the hard coat layer has a thickness of 1.2 to 10 μm.
(3) The optical reflective film according to (1) or (2), wherein the hard coat layer contains a surfactant.
(4) The optical reflective film according to any one of (1) to (3), wherein the hard coat layer contains an infrared absorber.
(5) The optical reflective film according to any one of (1) to (4), wherein the hard coat layer contains an acrylate resin.
(6) The hard coat layer was formed by applying a coating solution containing 5 to 20% by mass of a solvent having a relative evaporation rate of 0.1 to 0.5 with respect to the total amount of the solvent, and drying the coating solution. , (1) to (5) The optical reflective film according to any one of (1) to (5).
(7) The optical reflective film as described in any one of (1) to (6), wherein the relative evaporation rate of the hard coat coating solution is 1 to 3.5.
(8) A laminate including at least one unit in which a high refractive index layer and a low refractive index layer are laminated is formed by melt extrusion molding; a hard coat coating solution is applied to at least one surface side of the laminate. Forming a coating film; and drying so that the residual solvent in the laminate on which the coating film has been formed is 1 to 8 mg / g.
(9) The optical reflective film according to any one of (1) to (7) or the optical reflective film manufactured by the manufacturing method according to (8) is provided on at least one surface of the substrate. An optical reflector.

The effect of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples.

<Manufacturing example: Formation of reflection part by melt extrusion molding>
At least one unit in which a high refractive index layer and a low refractive index layer are laminated according to the melt extrusion molding method described in JP-T-2002-509279 (corresponding to US Pat. No. 6,049,419). The reflective part including was formed. Specifically, polyethylene naphthalate (PEN) (TN8065S, manufactured by Teijin Chemicals Ltd.) and polymethyl methacrylate (PMMA) (Acrypet (registered trademark) VH, manufactured by Mitsubishi Rayon Co., Ltd.) are melted at 300 ° C. and multilayer extrusion is performed. After extrusion onto a casting drum using a die, the film was stretched 3 times in the machine direction and 3 times in the transverse direction by a roll and a tenter, and (PMMA (152 nm) / PEN (137 nm)) 64 / (PMMA (164 nm) / PEN (148 nm)) 64 / (PMMA (177 nm) / PEN (160 nm)) 64 / (PMMA (191 m) / PEN (173 nm)) 64 A total of 256 laminated layers were obtained. Here, in the above layer configuration, “(PMMA (152 nm) / PEN (137 nm)) 64” means that there are 64 units in which PMMA having a film thickness of 152 nm and PEN having a film thickness of 137 nm are stacked in this order. Yes, other units are intended as well. From the relative relationship of the refractive index values, the layer made of PMMA is a low refractive index layer (refractive index: 1.49), and the layer made of PEN is a high refractive index layer (refractive index: 1.. 77).

<Example 1>
A hard coat coating solution (1) having a final concentration of the following composition was prepared. In the table, the relative evaporation rate of the hard coat coating solution was determined by the above mathematical formula (1).

The hard coat coating solution (1) was applied to one surface of the laminate obtained by the above-described method by gravure application so that the thickness of the hard coat layer after drying was 4 μm. Next, the laminate on which the hard coat coating film was formed was dried in an oven at 110 ° C. for 120 seconds. The obtained dried product was irradiated with active energy rays, and optical reflection film No. 1 was irradiated. (1) was obtained. The active energy ray was irradiated using a high-pressure mercury lamp under the conditions of an illuminance of 400 mW / cm ² and an irradiation amount of 800 mJ / cm ² .

A film piece was cut out from the obtained film perpendicularly to the film thickness direction and weighed (1 g). Next, the film piece was sealed in a vial, and the gas generated by heating at 120 ° C. for 30 minutes in an oven was measured by gas chromatography to determine the amount of residual solvent in the film. The measurement conditions for gas chromatography are as described above. The amount of residual solvent in the film was 7.8 mg / g (film). The residual solvent amount was measured within 12 hours after the production of the film.

<Examples 2 to 12, Comparative Examples 1 to 4>
In accordance with the method of Example 1, a hard coat layer was formed under the conditions shown in Table 2 below. (2) -No. (12) (Examples 2 to 12) and optical reflection film No. (13) to (16) (Comparative Examples 1 to 4) were obtained. Table 2 shows the amount of residual solvent in each optical reflection film.

<Evaluation>
(Haze)
Each optical reflection film was held for 48 hours in an environment of 50 ° C. and 80% relative humidity, and the haze difference before and after the measurement was measured with a haze meter (NDH2000, Nippon Denshoku Industries Co., Ltd.). 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 results are shown in Table 2.

(SWOM color change)
Each optical reflection film was affixed to white plate glass and stored for 1000 hours in a sunshine weather meter (SWOM) (manufactured by Suga Test Instruments Co., Ltd.) operated under the conditions specified in JIS K5400: 1990. The L ^* value, a ^* value, and b ^* value of the optical reflection film before and after storage were measured with a spectrophotometer (model name: U-4100 type, manufactured by Hitachi, Ltd.). ΔE was calculated by the following equation, where ΔL ^* was the difference in L ^* values before and after storage, Δa ^* was the difference in a ^* values, and Δb ^* was the difference in b ^* values. It shows that discoloration is so small that (DELTA) E is small. The results are shown in Table 2.

(Adhesion)
In accordance with the cross-cut method of JIS K5600-5-6: 1999, for each optical reflecting film, a single-blade razor blade was cross-cut at an angle of 90 ° with respect to the surface on the outermost surface of the film at intervals of 2 mm. A grid was made. Cellophane tape No. manufactured by Nitto Denko Corporation 29 was affixed to the hard coat layer, the tape was peeled off, and the peeled state of the hard coat layer was examined.

F = (n1 / n) × 100 (%) is calculated, where n is the number of cross-cut squares and n1 is the number of squares where the hard coat layer remains in the laminate after peeling off the tape. Evaluation based on the criteria. The results are shown in Table 2. A: F is 100%,
○: F is 80% or more and less than 100%,
Δ: F is 50% or more and less than 80%,
X: F is less than 50%.

As is clear from Table 2, it can be seen that the optical reflective film according to the present invention has excellent weather resistance and high adhesion of the hard coat layer.

This application is based on Japanese Patent Application No. 2014-133112 filed on June 27, 2014, the disclosure of which is incorporated herein by reference in its entirety.

10 Optical reflective film,
11 Reflector,
12 Hard coat layer,
13 Adhesive layer,
111 low refractive index layer,
112 high refractive index layer,
113 units.

Claims

A reflective portion formed by melt extrusion, comprising at least one unit in which a high refractive index layer and a low refractive index layer are laminated; and
An optical reflective film comprising a hard coat layer formed by application of a hard coat coating solution,
An optical reflective film, wherein the residual solvent in the film is 1 to 8 mg / g.
2. The optical reflective film according to claim 1, wherein the thickness of the hard coat layer is 1.2 to 10 μm.
The optical reflection film according to claim 1, wherein the hard coat layer contains a surfactant.
The optical reflective film according to any one of claims 1 to 3, wherein the hard coat layer contains an infrared absorber.
The optical reflection film according to any one of claims 1 to 4, wherein the hard coat layer contains an acrylate resin.
The hard coat layer is formed by applying a coating solution containing 5 to 20% by mass of a solvent having a relative evaporation rate of 0.1 to 0.5 with respect to the total amount of the solvent and drying. 6. The optical reflection film according to any one of 1 to 5.
The optical reflective film according to any one of claims 1 to 6, wherein the relative evaporation rate of the hard coat coating solution is 1 to 3.5.
Forming a laminate including at least one unit in which a high refractive index layer and a low refractive index layer are laminated by melt extrusion;
Applying a hard coat coating solution to at least one side of the laminate to form a coating film; and drying so that the residual solvent in the laminate on which the coating film is formed is 1 to 8 mg / g. The manufacturing method of the optical reflection film containing these.
An optical reflector comprising the optical reflective film according to any one of claims 1 to 7 or the optical reflective film produced by the production method according to claim 8 provided on at least one surface of a substrate.