JP6344069B2 - Optical reflective film - Google Patents

Description

  The present invention relates to an optical reflection film.

  In general, a dielectric multilayer film in which a high refractive index layer and a low refractive index layer are laminated on the surface of a substrate by adjusting the optical film thickness can selectively reflect light of a specific wavelength. Are known. Such a dielectric multilayer film is used, for example, as an optical reflection film installed on a building window or a vehicle member. 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.

  The optical reflection film as described above is provided with a hard coat layer on the surface opposite to the surface on which the dielectric multilayer film is formed for the purpose of improving the scratch resistance of the film. Sometimes. However, in an optical film in which a hard coat layer is provided on one surface of a substrate, curling is likely to occur due to curing shrinkage of the hard coat layer.

  In addition, when an optical reflective film having a hard coat layer and a dielectric multilayer film is affixed inside a car or indoors, the dielectric multilayer film and the hard coat layer change in dimensions due to changes in temperature and humidity in the environment, respectively. There is a problem that cracks and peeling occur due to dimensional change. In addition, when the light-shielding particles are contained in the hard coat layer, the brittleness of the hard coat is lowered, and the occurrence of cracks and peeling becomes remarkable.

  As a means for suppressing the occurrence of curling in an optical film in which a hard coat layer is provided on one surface of a substrate, for example, Patent Document 1 discloses an optical film in which a hard coat layer is provided on one side of a film substrate. In the manufacturing process, a method is described in which, after the hard coat layer is cured, the curl is controlled by applying water vapor or solvent vapor to the surface opposite to the surface on which the hard coat layer is provided, and controlling the transport tension. Patent Document 2 discloses a method for curling a hard coat film in which a hard coat layer is laminated on a resin substrate by controlling the elastic modulus related to the flexural elasticity of the hard coat layer and the thickness of the hard coat layer. Is described.

  As a means for suppressing a decrease in adhesion of the hard coat layer due to changes in temperature and humidity in the environment, for example, Patent Document 3 discloses an infrared ray shielding in which a hard coat layer containing infrared ray shielding fine particles is formed on one side of a plastic film. In the film, it is described that a functional resin layer made of a specific resin is provided between a plastic layer and a hard coat layer.

JP2012-14115A International Publication No. 2003/026881 JP 2002-210855 A

  However, in the techniques of Patent Documents 1 to 3, it has been found that when the optical reflective film is exposed to an environment with a change in humidity for a long period of time, cracks and peeling occur in the hard coat layer. In particular, a film for window glass also has a humidity change due to condensation and the like, and since it is exposed to sunlight for a long time, high weather resistance is required.

  The present invention has been made in view of the above problems. In an optical reflective film having a structure in which a dielectric multilayer film is provided on one surface of a substrate and a hard coat layer is provided on the other surface, the weather resistance is improved. An object of the present invention is to provide a means capable of improving and suppressing the occurrence of cracks in a hard coat layer.

  In view of the above problems, the present inventors have intensively studied. As a result, the inventors have found that the above problem can be solved by controlling the fluctuation of the curl value of the optical reflecting film due to the change of humidity in the environment within a predetermined range, and have completed the present invention.

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

  1. A base material, a dielectric multilayer film formed by alternately laminating a low refractive index layer and a high refractive index layer, disposed on one surface of the base material, and disposed on the other surface of the base material An optical reflective film having a hard coat layer, wherein the optical reflective film is cut to a size of 50 mm in the width direction at the time of manufacture and 3 mm in the longitudinal direction, and in the width direction at the time of manufacture. Both the sample cut to a size of 3 mm and 50 mm in the longitudinal direction had a curl value measured by placing in an environment of a temperature of 23 ° C. and a relative humidity of 50% for 1 hour, a (1 / m), a temperature of 23 ° C., The curl value measured for 1 hour in an environment with a relative humidity of 20% is b (1 / m), and the curl value measured for 1 hour in an environment with a temperature of 23 ° C. and a relative humidity of 80% is c (1 / m). ), The following formulas (1) and (2) are satisfied. Manabu reflection film.

  2. A curl value obtained by measuring a sample obtained by cutting the optical reflective film into a size of 50 mm in the width direction and 3 mm in the longitudinal direction at the time of production in an environment of a temperature of 23 ° C. and a relative humidity of 50%, and production. Samples cut to a size of 3 mm in the width direction and 50 mm in the longitudinal direction at the time are opposite in polarity to the curl value measured for 1 hour in an environment of a temperature of 23 ° C. and a relative humidity of 50%. The optical reflective film as described in 2.

  3. 3. The optical reflection film as described in 1 or 2 above, wherein the hard coat layer has a thickness of 1 to 5 μm.

  4). Any of the above 1-3, wherein the ratio of the thickness of the hard coat layer to the thickness of the dielectric multilayer film (the thickness of the hard coat layer / the thickness of the dielectric multilayer film) is 0.2-2. The optical reflection film according to item 1.

  5. The optical according to any one of 1 to 4, wherein the hard coat layer is obtained by curing a composition containing a hydroxyl group-containing polyfunctional urethane acrylate, a photopolymerization initiator, and infrared absorbing metal oxide nanoparticles. Reflective film.

  6). 6. The optical reflective film as described in 5 above, wherein the content of the infrared absorbing metal oxide nanoparticles in the hard coat layer is 20 to 50% by mass.

  7). The optical reflective film according to any one of 1 to 6, wherein the dielectric multilayer film contains a water-soluble resin.

  According to the present invention, in an optical reflective film having a structure in which a dielectric multilayer film is provided on one surface of a substrate and a hard coat layer is provided on the other surface, the curl of the optical reflective film caused by a change in humidity in the environment. By controlling the fluctuation of the value within a predetermined range, occurrence of cracks and peeling in the hard coat layer is suppressed, and high weather resistance is obtained.

One embodiment of the present invention includes a base material, a dielectric multilayer film in which low refractive index layers and high refractive index layers are alternately stacked, and disposed on one surface of the base material. A hard coat layer disposed on the other surface;
A sample obtained by cutting the optical reflective film into a size of 50 mm in the width direction at the time of manufacture and 3 mm in the length direction, and 3 mm in the width direction at the time of manufacture, and 50 mm in the length direction. The curl value measured for 1 hour in an environment with a temperature of 23 ° C. and a relative humidity of 50% was a (1 / m), the temperature was 23 ° C., and the relative humidity was 20%. The curl value measured by placing it under 1 hour under the condition b (1 / m), the temperature measured at 23 ° C. and the relative humidity 80% for 1 hour as c (1 / m) It is an optical reflection film satisfying the formulas (1) and (2).

  According to the optical reflective film according to an embodiment of the present invention having such a configuration, generation of cracks in the hard coat layer can be suppressed, and the scratch resistance of the hard coat layer can be improved.

  In an optical reflective film having a configuration in which a dielectric multilayer film is provided on one surface of a substrate and a hard coat layer is provided on the other surface, a resin such as an active energy ray curable resin is used as the hard coat layer. In this case, volume shrinkage occurs at the time of curing, and curling of the optical reflective film tends to occur particularly when the film thickness is increased. Further, the resin constituting the hard coat layer and the resin constituting the dielectric multilayer film expand and contract in volume depending on the amount of moisture absorption, resulting in dimensional changes of the hard coat layer and the dielectric multilayer film. In particular, the resin constituting the hard coat layer has a large volume expansion and contraction, and a large amount of dimensional change due to moisture absorption. Furthermore, since the elastic modulus is higher than that of the resin constituting the dielectric multilayer film, the stress tends to increase with respect to the dimensional change. In this way, dimensional changes of the hard coat layer and dielectric multilayer film occur due to humidity fluctuations in the environment, and stress changes occur. When the cycle is repeated, the stress difference accumulates and the hard coat layer accumulates. Adhesion is lowered and becomes brittle, causing cracks and peeling.

  Therefore, the dimensional change of the hard coat layer or dielectric multilayer film due to the change of humidity in the environment occurs, or the change of stress is measured as the curl value of the optical reflective film, and the amount of change in humidity in the biaxial direction of the value is measured. By controlling to a predetermined range, there is also a change in humidity due to condensation, especially for film for window glass, etc., and there is a change in temperature and humidity over a long period of time, such as an environment exposed to sunlight for a long time. It became clear that even when exposed to the environment, the accumulation of stress differences can be reduced, and the occurrence of cracks and peeling in the hard coat layer can be dramatically suppressed.

  The fluctuation of the curl value of the optical reflective film due to changes in the humidity in the environment can be achieved, for example, by adjusting the thickness and material of the hard coat layer and the dielectric multilayer film to balance the stress applied to the hard coat layer and the dielectric multilayer film. It can be controlled by taking

  Specifically, when the thickness of the hard coat layer is increased, the stress in the direction of curling that causes the inner surface of the hard coat layer to increase is increased, and when the thickness of the dielectric multilayer film is increased, the dielectric multilayer is increased. The stress in the direction in which the film side surface becomes the inner winding increases. Further, when the hard coat layer includes infrared absorbing metal oxide nanoparticles, the more the content of the infrared absorbing metal oxide nanoparticles, the more likely the curl that the inner surface of the hard coat layer is to be curled. In addition, some infrared absorbing metal oxide nanoparticles have ultraviolet absorbing ability (for example, ATO, ITO), and the weather resistance can be further improved by adding an appropriate amount of these particles. it can. Therefore, by controlling the thickness of the hard coat layer and the dielectric multilayer film, the type of resin, and the content of the infrared-absorbing metal oxide nanoparticles, curling balance can suppress fluctuations in curling value due to humidity. Can do. Furthermore, when using a resin whose volume change is relatively large due to humidity fluctuation as the resin constituting the hard coat layer, curling balance is achieved by reducing the film thickness of the hard coat layer, and fluctuation of the curl value due to humidity is suppressed. be able to.

  In the present specification, the curl value is a value represented by 1 / R (R is the radius of curvature (m) of curl), and can be measured by the method described in the examples described later. In this specification, the curl value represents the curl value of the curl with the inner surface on the hard coat layer side of the optical reflection film as a positive value, and the curl value with the inner surface of the dielectric multilayer film side. The curl value of is represented as a negative value.

  The optical reflective film of the present invention has a curl value (curl value in the width direction) measured using a sample cut to a size of 50 mm in the width direction at the time of manufacture and 3 mm in the length direction, and a value at the time of manufacture. All of the curl values (curl values in the longitudinal direction) measured using a sample cut to a size of 3 mm in the width direction and 50 mm in the longitudinal direction satisfy the above formulas (1) and (2).

  Here, the optical reflective film of the present invention is manufactured by forming a dielectric multilayer film on one surface of a substrate, and then forming a hard coat layer on the other surface of the substrate. The film transport direction when producing the film is defined as the longitudinal direction, and the direction perpendicular thereto is defined as the width direction.

  Preferably, in the optical reflective film of the present invention, the absolute value of the curl value a (1 / m) measured for 1 hour in an environment of a temperature of 23 ° C. and a relative humidity of 50% is a curl value in the width direction and a longitudinal direction. Any of the direction curl values is 20 or less, more preferably 10 or less, and still more preferably 8 or less. By setting it as the said range, the optical reflection film excellent in the weather resistance can be obtained.

  Also, the value of | b (1 / m) −a (1 / m) | on the left side of the above equation (1) (hereinafter also referred to as A value) and | c (1 / The value of m) −a (1 / m) | (hereinafter also referred to as “B value”) is more preferably 2 (1 / m) or less in both the width direction and the longitudinal direction.

  In the optical reflective film of the present invention, a sample obtained by cutting the optical reflective film into a size of 50 mm in the width direction and 3 mm in the longitudinal direction at the time of manufacture is placed in an environment of a temperature of 23 ° C. and a relative humidity of 50% for 1 hour. And a curl value measured by placing a sample cut to a size of 3 mm in the width direction and 50 mm in the longitudinal direction at the time of manufacturing in an environment of a temperature of 23 ° C. and a relative humidity of 50% for 1 hour. It is preferable that the sign is reversed. By controlling the curl in the width direction of the film and the curl in the longitudinal direction at the time of production in opposite directions, the stress of each layer is relieved and the weather resistance is further improved. The direction of the curl in the width direction and the curl in the longitudinal direction at the time of manufacture is the thickness and material of the hard coat layer and the dielectric multilayer film, the stretching at the time of manufacturing the dielectric multilayer film, the stretching direction, the stretching ratio, etc. It can be controlled by adjusting. For example, in a direction in which the dielectric multilayer film is stretched, stress in a direction in which a curl in which the surface on the dielectric multilayer film side becomes inward is more likely to occur. That is, the strength of curl on the surface on the dielectric multilayer film side in the longitudinal direction and the width direction of the film can be adjusted by the stretch ratio.

  Hereinafter, the components of the optical reflection film according to the present invention, and the forms and modes for carrying out the present invention will be described in detail.

[Base material]
The substrate has a function capable of forming a film in the coating and drying process.

  The substrate is preferably transparent, and various resin films can be used. For example, polyolefin film (polyethylene, polypropylene, etc.), polyester film (polyethylene terephthalate, polyethylene naphthalate, etc.), polyvinyl chloride, cellulose triacetate, polyimide, polybutyral film, cycloolefin polymer film, transparent cellulose nanofiber film, etc. Can be used. Among these, it is preferable to use a polyester film.

  Among the polyester films, from the viewpoint of transparency, mechanical strength, dimensional stability and the like, dicarboxylic acid components such as terephthalic acid and 2,6-naphthalenedicarboxylic acid, and diols such as ethylene glycol and 1,4-cyclohexanedimethanol It is preferable that it is polyester which has the film formation property which makes a component a main structural component. Of these, polyesters mainly composed of polyethylene terephthalate and polyethylene naphthalate, copolymerized polyesters composed of terephthalic acid, 2,6-naphthalenedicarboxylic acid and ethylene glycol, and mixtures of two or more of these polyesters are mainly used. Polyester as a constituent component is preferable.

  The material and film thickness of the substrate are preferably set so that the value obtained by dividing the thermal shrinkage rate of the optical reflective film by the thermal shrinkage rate of the substrate is in the range of 1 to 3.

  Especially, it is preferable that the film thickness of a base material is 30-200 micrometers, It is more preferable that it is 30-150 micrometers, It is most preferable that it is 35-125 micrometers. It is preferable that the thickness of the substrate is 30 μm or more because wrinkles during handling are less likely to occur. On the other hand, when the thickness of the substrate is 200 μm or less, for example, when the substrate is bonded to the transparent substrate, the followability to the curved transparent substrate is improved and wrinkles are less likely to occur.

  The substrate is preferably a biaxially oriented polyester film, but an unstretched or at least one stretched polyester film can also be used. A stretched film is preferable from the viewpoint of improving strength and suppressing thermal expansion. In particular, when it is used as a laminated glass for an automobile windshield, a stretched film is more preferable.

(Dielectric multilayer film)
The dielectric multilayer film has a configuration in which low refractive index layers and high refractive index layers are alternately stacked, and has at least one unit composed of a low refractive index layer and a high refractive index layer. Since the dielectric multilayer film includes the refractive index layers having different refractive indexes in this way, when light having a predetermined wavelength (for example, infrared light) is incident, at least a part of this light is It can reflect and can exhibit the shielding effect (and heat shielding effect in the case of infrared light).

  In the present embodiment, whether the refractive index layer constituting the dielectric multilayer film is a low refractive index layer or a high refractive index layer is determined by comparing the refractive index with the adjacent refractive index layer. Specifically, when a refractive index layer is used as a reference layer, if the refractive index layer adjacent to the reference layer has a lower refractive index than the reference layer, the reference layer is a high refractive index layer (the adjacent layer is a low refractive index layer). It is judged to be a rate layer. On the other hand, if the refractive index of the adjacent layer is higher than that of the reference layer, it is determined that the reference layer is a low refractive index layer (the adjacent layer is a high refractive index layer). 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. Depending on the relationship, it can be a high refractive index layer or a low refractive index layer.

  Although there is no restriction | limiting in particular as a refractive index layer, It is preferable to use the well-known refractive index layer used in the said technical field preferably. As a known refractive index layer, for example, a refractive index layer formed using a dry film forming method, a refractive index layer formed by extrusion molding of a resin, and a refractive index layer formed using a wet film forming method Is mentioned.

  Further, from the viewpoint of reflection characteristics, at least one of the high refractive index layer and the low refractive index layer preferably includes metal oxide particles, and both the high refractive index layer and the low refractive index layer include metal oxide particles. It is more preferable.

  In the dielectric multilayer film of the optical reflective film of the present invention, it is preferable to use a water-soluble resin for at least one of the high refractive index layer and the low refractive index layer. Moreover, it is preferable that the refractive index layer of the optical reflection film formed by the wet film forming method is a coating film coated with a coating solution containing a water-soluble resin (usually containing an aqueous solvent such as water). The water-soluble resin is preferable because it does not use an organic solvent, has a low environmental load, and has high flexibility, so that the durability of the film during bending is improved. The water-soluble resin is suitably used particularly when metal oxide nanoparticles are included in at least one of the high refractive index layer and the low refractive index layer.

  In this specification, “water-soluble” means a G2 glass filter (maximum pores 40 to 50 μm) when dissolved in water at a temperature at which the substance is most dissolved and having a concentration of 0.5% by mass. This means that the mass of insoluble matter to be filtered out is within 50% by mass of the added polymer.

  As described above, whether the layer is a low refractive index layer or a high refractive index layer is a relative one that is determined by the relationship with the adjacent refractive index layer. The structure of a typical high refractive index layer and low refractive index layer among the refractive index layers that can be formed by the respective methods will be described below.

(Refractive index layer formed by resin extrusion)
In the present invention, the resin that can be used in the alternating high refractive index layer and low refractive index layer is not particularly limited, but at least one layer is preferably birefringent and oriented. For example, those described in JP-T-2008-528313 and those appropriately modified can be used.

  Specific examples include polyethylene terephthalate (PET), polyethylene terephthalate copolymer (coPET), poly (methyl methacrylate) (PMMA), poly (methyl methacrylate) copolymer (coPMMA), terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer Examples thereof include, but are not limited to, a polymer (PETG), polyethylene naphthalate (PEN), and a copolymer of polyethylene naphthalate (coPEN). For each high refractive index layer and low refractive index layer, one or a combination of two or more of these resins can be used. Examples of suitable resin combinations include those described in US Pat. No. 6,352,761. Using the resin, a dielectric multilayer film can be formed by a continuous flat film production line, for example, by a coextrusion method.

(Refractive index layer formed by wet film formation method)
In the wet film forming method, the refractive index layer can be formed by a method of sequentially applying and drying the coating solution, a method of applying and drying the coating solution in multiple layers, and the like. The refractive index layer of the optical reflective film according to this embodiment is preferably formed by this wet film-forming method, and more preferably formed by a method of applying and drying a coating solution in multiple layers.

High refractive index layer The high refractive index layer preferably contains a water-soluble resin. In addition, metal oxide particles, a curing agent, a surfactant, and other additives may be included as necessary. The water-soluble resin and metal oxide particles contained in the high refractive index layer are hereinafter referred to as “first water-soluble resin” and “first metal oxide particles” for convenience.

  At this time, the refractive index of the first metal oxide particles is preferably higher than the refractive index of the second metal oxide particles contained in the low refractive index layer described later. By containing metal oxide particles in the high refractive index layer and / or the low refractive index layer, the difference in refractive index between the refractive index layers can be increased, and the transparency of the film is increased by reducing the number of layers. This is preferable because it can be performed. In addition, there is an advantage that stress relaxation works and film properties (flexibility at the time of bending and high temperature and high humidity) are improved. The metal oxide particles may be contained in any one of the refractive index layers, but a preferable form is that at least the high refractive index layer includes metal oxide particles, and more preferable forms are the high refractive index layer and the low refractive index layer. All of the rate layers are in a form containing metal oxide particles.

(1) First water-soluble resin The first water-soluble resin is not particularly limited, and polyvinyl alcohol resins, gelatin, celluloses, thickening polysaccharides, and polymers having reactive functional groups can be used. . Of these, it is preferable to use a polyvinyl alcohol-based resin.

Polyvinyl alcohol resin As the polyvinyl alcohol resin, ordinary polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate (unmodified polyvinyl alcohol), cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, nonion-modified polyvinyl alcohol, vinyl alcohol Examples thereof include modified polyvinyl alcohol such as a polymer. The modified polyvinyl alcohol may improve the film adhesion, water resistance, and flexibility.

Gelatin As the gelatin, various gelatins that have been widely used in the field of silver halide photographic light-sensitive materials can be applied. For example, acid-treated gelatin, alkali-treated gelatin, enzyme-treated gelatin that undergoes enzyme treatment in the production process of gelatin, a group having an amino group, imino group, hydroxyl group, carboxyl group as a functional group in the molecule, and a group that can react with it And gelatin derivatives modified by treatment with a reagent having

  When gelatin is used, a gelatin hardener can be added as necessary.

Cellulose As the cellulose, a water-soluble cellulose derivative can be preferably used. For example, water-soluble cellulose derivatives such as carboxymethyl cellulose (cellulose carboxymethyl ether), methyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose; carboxylic acid group-containing celluloses such as carboxymethyl cellulose (cellulose carboxymethyl ether) and carboxyethyl cellulose; Examples thereof include cellulose derivatives such as cellulose, cellulose acetate propionate, cellulose acetate, and cellulose sulfate.

Thickening polysaccharides Thickening polysaccharides are saccharide polymers that have many hydrogen bonding groups in the molecule. The thickening polysaccharide has a characteristic that the viscosity difference at low temperature and the viscosity at high temperature are large due to the difference in hydrogen bonding force between molecules depending on temperature. Further, when metal oxide fine particles are added to the thickening polysaccharide, the viscosity is increased due to hydrogen bonding with the metal oxide fine particles at a low temperature. As for the viscosity increase range, the viscosity at 15 ° C. is usually 1.0 mPa · s or more, preferably 5.0 mPa · s or more, more preferably 10.0 mPa · s or more.

  The thickening polysaccharide that can be used is not particularly limited and includes generally known natural simple polysaccharides, natural complex polysaccharides, synthetic simple polysaccharides, and synthetic complex polysaccharides. For details of these polysaccharides, reference can be made to “Biochemical Encyclopedia (2nd edition), Tokyo Chemical Doujinshi”, “Food Industry”, Vol. 31 (1988), p.

Polymers having reactive functional groups Examples of polymers having reactive functional groups include polyvinylpyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymers, potassium acrylate-acrylonitrile copolymers, vinyl acetate-acrylic esters. Acrylic resins such as copolymers and acrylic acid-acrylic acid ester copolymers; styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid-acrylic acid ester copolymers, styrene-α -Styrene acrylic resin such as methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer; styrene-sodium styrenesulfonate copolymer, styrene-2-hydroxyethyl acrylate Copolymer, styrene 2-hydroxyethyl acrylate-potassium styrene sulfonate copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinyl naphthalene-acrylic acid copolymer, vinyl naphthalene-maleic acid copolymer, And vinyl acetate-based copolymers such as vinyl acetate-maleic acid ester copolymer, vinyl acetate-crotonic acid copolymer, vinyl acetate-acrylic acid copolymer; and salts thereof. Of these, polyvinylpyrrolidones and copolymers containing the same are preferably used.

  The water-soluble resins described above may be used alone or in combination of two or more.

  The weight average molecular weight of the first water-soluble resin is preferably 1000 to 200000, and more preferably 3000 to 40000. In the present specification, the value measured by gel permeation chromatography (GPC) is adopted as the value of “weight average molecular weight”.

  The content of the first water-soluble resin is preferably 5 to 50% by mass and more preferably 10 to 40% by mass with respect to 100% by mass of the solid content of the high refractive index layer.

(2) First metal oxide particles The first metal oxide particles are not particularly limited, but are preferably metal oxide particles having a refractive index of 2.0 to 3.0. Specifically, titanium oxide, zirconium oxide, zinc oxide, alumina, colloidal alumina, lead titanate, red lead, yellow lead, zinc yellow, chromium oxide, ferric oxide, iron black, copper oxide, magnesium oxide, water Examples thereof include magnesium oxide, strontium titanate, yttrium oxide, niobium oxide, europium oxide, lanthanum oxide, zircon, and tin oxide. Among these, the first metal oxide particles are preferably titanium oxide or zirconium oxide from the viewpoint of forming a transparent and high refractive index layer having a high refractive index. From the viewpoint of improving weather resistance, the first metal oxide particles are preferably a rutile type (tetragonal type). ) Titanium oxide is more preferable.

  The titanium oxide may be in the form of core / shell particles coated with a silicon-containing hydrated oxide. The core / shell particles have a structure in which the surface of the titanium oxide particles is coated with a shell made of a silicon-containing hydrated oxide on titanium oxide serving as a core. In this case, the volume average particle size of the titanium oxide particles serving as the core portion is preferably more than 1 nm and less than 30 nm, and more preferably 4 nm or more and less than 30 nm. By including such core / shell particles, the intermixing of the high refractive index layer and the low refractive index layer can be suppressed by the interaction between the silicon-containing hydrated oxide of the shell layer and the water-soluble resin. .

  The first metal oxide particles described above may be used alone or in combination of two or more.

  The content of the first metal oxide particles is 15 to 80% by mass with respect to 100% by mass of the solid content of the high refractive index layer from the viewpoint of increasing the refractive index difference from the low refractive index layer. Preferably, it is 20-77 mass%, More preferably, it is 30-75 mass%.

  The first metal oxide particles preferably have a volume average particle size of 30 nm or less, more preferably 1 to 30 nm, and even more preferably 5 to 15 nm. A volume average particle size of 30 nm or less is preferable because it has less haze and is excellent in visible light transmittance. In the present specification, the value measured by the following method is adopted as the value of “volume average particle diameter”. Specifically, arbitrary 1000 particles appearing on the cross section or surface of the refractive index layer are observed with an electron microscope to measure the particle size, and particles having particle sizes of d1, d2,. In the group of n1, n2... Ni... Nk metal oxide particles, where the volume per particle is vi, the volume average particle size (mv) is calculated by the following formula.

(3) Curing Agent The curing agent has a function of reacting with the first water-soluble resin (preferably polyvinyl alcohol resin) contained in the high refractive index layer to form a hydrogen bond network.

  The curing agent is not particularly limited as long as it causes a curing reaction with the first water-soluble resin, but in general, a compound having a group capable of reacting with the water-soluble resin or a different group possessed by the water-soluble resin. The compound which accelerates | stimulates mutual reaction is mentioned.

  As a specific example, when polyvinyl alcohol is used as the first water-soluble resin, it is preferable to use boric acid and its salt as a curing agent. Moreover, you may use well-known hardening | curing agents other than boric acid and its salt.

  In addition, boric acid and its salt mean the oxygen acid which has a boron atom as a central atom, and its salt. Specific examples include orthoboric acid, diboric acid, metaboric acid, tetraboric acid, pentaboric acid, octaboric acid, and salts thereof.

  The content of the curing agent is preferably 1 to 10% by mass and more preferably 2 to 6% by mass with respect to 100% by mass of the solid content of the high refractive index layer.

  In particular, the total amount of the curing agent when polyvinyl alcohol is used as the first water-soluble resin is preferably 1 to 600 mg per 1 g of polyvinyl alcohol, and more preferably 10 to 600 mg per 1 g of polyvinyl alcohol. .

Surfactant The surfactant is not particularly limited. However, the amphoteric surfactant, the cationic surfactant, the anionic surfactant, the nonionic surfactant, the fluorosurfactant, and the silicon surfactant. Is mentioned. Among these, acrylic surfactants, silicon surfactants, or fluorine surfactants are used. As the surfactant, a surfactant containing a long-chain alkyl group is preferable, and a surfactant having an alkyl group having 6 to 20 carbon atoms is more preferable.

  Zwitterionic surfactants include alkylbetaines, alkylamine oxides, cocamidopropyl betaines, lauramidopropyl betaines, palm kernel fatty acid amidopropyl betaines, cocoamphoacetic acid N, lauroamphoacetic acid Na, lauramidopropyl hydroxysultains, lauramide Examples include propylamine oxide, myristamidopropylamine oxide, and hydroxyalkyl (C12-14) hydroxyethyl sarcosine.

  Examples of the cationic surfactant include alkylamine salts and quaternary ammonium salts.

  Examples of the anionic surfactant include alkyl sulfate ester salts, polyoxyethylene alkyl ether sulfate ester salts, alkylbenzene sulfonate salts, fatty acid salts, polyoxyethylene alkyl ether phosphate salts, and dipotassium alkenyl succinate.

  Examples of the nonionic surfactant include polyoxyethylene alkyl ether (for example, Emulgen manufactured by Kao), polyoxyethylene sorbitan fatty acid ester (for example, Leodol TW series manufactured by Kao), glycerin fatty acid ester, polyoxyethylene fatty acid ester, poly Examples thereof include oxyethylene alkylamine and alkyl alkanolamide.

  Fluorosurfactants include Surflon S-211, S-221, S-231, S-241, S-242, S-243, S-420 (manufactured by AGC Seimi Chemical Co., Ltd.), Megafac F-114, F-410, F-477, F-553 (made by DIC Corporation), FC-430, FC-4430, FC-4432 (made by 3M company) are mentioned.

  Examples of the silicon surfactant include BYK-345, BYK-347, BYK-348, and BYK-349 (manufactured by BYK Japan).

  The high refractive index layer can also contain other additives. Examples of other additives include amino acids, emulsion resins, lithium compounds, and the like. Further, ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988, JP-A-62-261476; JP-A-57-74192, JP-A-57-87989 Japanese Patent Laid-Open No. 60-72785, Japanese Patent Laid-Open No. 61-14659, Japanese Patent Laid-Open No. 1-95091, Japanese Patent Laid-Open No. 3-13376, etc .; Japanese Patent Laid-Open No. 59-42993 , Whitening agents described in JP-A-59-52689, JP-A-62-280069, JP-A-61-228771, JP-A-4-219266, etc .; sulfuric acid, phosphoric acid, PH adjusters such as acetic acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate; antifoaming agents; lubricants such as diethylene glycol; antiseptics; antifungal agents; antistatic agents; matting agents; Antioxidant; flame retardants; crystal nucleating agent; inorganic particles; organic particles; viscosity reducers; lubricants; infrared absorber; dyes; known various additives such as a pigment or the like may be used as other additives.

Low Refractive Index Layer The low refractive index layer preferably also contains a water soluble resin. In addition, metal oxide particles, a curing agent, a surfactant, and other additives may be included as necessary. The water-soluble resin and metal oxide particles contained in the low refractive index layer are hereinafter referred to as “second water-soluble resin” and “second metal oxide particles” for convenience.

(1) Second water-soluble resin As the second water-soluble resin, the same one as the first water-soluble resin can be used.

  At this time, when the high refractive index layer and the low refractive index layer both use a polyvinyl alcohol-based resin as the first water-soluble resin and the second water-soluble resin, the polyvinyl alcohol-based resins having different degrees of saponification are used. It is preferable to use a resin. Thereby, mixing of the interface is suppressed, the infrared reflectance (infrared shielding rate) becomes better, and the haze can be lowered. In the present specification, the “degree of saponification” means the ratio of hydroxy groups to the total number of acetyloxy groups (derived from vinyl acetate as a raw material) and hydroxy groups in polyvinyl alcohol.

(2) Second metal oxide particles The second metal oxide particles are not particularly limited, but it is preferable to use silica (silicon dioxide) such as synthetic amorphous silica or colloidal silica, and acidic colloidal silica sol. It is more preferable to use Further, from the viewpoint of further reducing the refractive index, hollow fine particles having pores inside the particles can be used as the second metal oxide particles, and it is particularly preferable to use hollow fine particles of silica (silicon dioxide). .

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

  The second metal oxide particles may be surface-coated with a surface coating component.

  The second metal oxide particles (preferably silicon dioxide) contained in the low refractive index layer of the present invention preferably have an average particle size (number average; diameter) of 3 to 100 nm, preferably 3 to 50 nm. It is more preferable. In the present specification, the “average particle diameter (number average; diameter)” of the metal oxide fine particles is 1,000 particles observed by an electron microscope on the particles themselves or on the cross section or surface of the refractive index layer. The particle size of any of the particles is measured and determined as a simple average value (number average). Here, the particle diameter of each particle is represented by a diameter assuming a circle equal to the projected area.

  The content of the second metal oxide particles in the low refractive index layer is preferably 0.1 to 70% by mass and 30 to 70% by mass with respect to 100% by mass of the total solid content of the low refractive index layer. It is more preferable that it is 45-65 mass%.

  The above-mentioned second metal oxide may be used alone or in combination of two or more from the viewpoint of adjusting the refractive index.

Curing Agent, Surfactant, and Other Additives As the curing agent, surfactant, and other additives, the same materials as those for the high refractive index layer can be used, and the description thereof is omitted here.

  In the dielectric multilayer film in which the high refractive index layer and the low refractive index layer having the above-described configuration are alternately laminated, at least one of the high refractive index layer and the low refractive index layer uses a wet film forming method. The refractive index layer is preferably formed, and both the high refractive index layer and the low refractive index layer are more preferably refractive index layers formed using a wet film forming method. Furthermore, it is preferable that at least one of the high refractive index layer and the low refractive index layer includes metal oxide particles, and it is more preferable that both the high refractive index layer and the low refractive index layer include metal oxide particles.

(Manufacturing method of dielectric multilayer film)
The dielectric multilayer film in the present invention can be formed by applying and drying a coating solution for forming a high refractive index layer and a coating solution for forming a low refractive index layer. The components of the high refractive index layer forming coating solution and the low refractive index layer forming coating solution can be appropriately adjusted depending on the desired dielectric multilayer film. For example, the process of forming a dielectric multilayer film by forming a high refractive index layer and a low refractive index layer from a polymer in the case of not containing metal oxide particles is not particularly limited. For example, JP-T-2008-528313 Can be applied in the same manner or with appropriate modification.

  Below, the formation process of the dielectric multilayer when the first metal oxide particles are included in the high refractive index layer and the second metal oxide particles are included in the low refractive index layer will be exemplarily described. Each layer can also contain a resin.

[Coating liquid for forming a high refractive index layer]
The coating liquid for forming a high refractive index layer preferably contains a first water-soluble resin and first metal oxide particles. Moreover, you may further contain at least 1 sort (s) selected from the group which consists of a hardening | curing agent, surfactant, and various additives as needed. Since specific forms of the first water-soluble resin, the first metal oxide particles, the curing agent, the surfactant, and the various additives are as described above, description thereof is omitted here.

  In addition, it is preferable that the density | concentration of 1st water-soluble resin in the coating liquid for high refractive index layer formation is 1-10 mass%, and it is more preferable that it is 1-8 mass%. Moreover, it is preferable that the density | concentration of the 1st metal oxide particle in the coating liquid for high refractive index layer formation is 1-50 mass%, and it is more preferable that it is 1-20 mass%.

  The solvent for preparing the coating solution for forming a high refractive index layer is not particularly limited, but water, an organic solvent, or a mixed solvent thereof is preferable. In consideration of environmental aspects due to the scattering of the organic solvent, water or a mixed solvent of water and a small amount of an organic solvent is more preferable, and water is particularly preferable. Examples of the organic solvent include alcohols such as methanol, ethanol, 2-propanol and 1-butanol, esters such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate, diethyl ether, Examples thereof include ethers such as propylene glycol monomethyl ether and ethylene glycol monoethyl ether, amides such as dimethylformamide and N-methylpyrrolidone, and ketones such as acetone, methyl ethyl ketone, acetylacetone and cyclohexanone. These organic solvents may be used alone or in combination of two or more. From the viewpoint of environment and simplicity of operation, the solvent of the coating solution is preferably water or a mixed solvent of water and methanol, ethanol, or ethyl acetate, and more preferably water.

  When using a mixed solvent of water and a small amount of an organic solvent, the content of water in the mixed solvent is preferably 80 to 99.9% by mass, based on 100% by mass of the entire mixed solvent, and 90 to 99%. More preferably, it is 5 mass%. Here, by setting it to 80% by mass or more, volume fluctuation due to solvent volatilization can be reduced, handling is improved, and by setting it to 99.9% by mass or less, homogeneity at the time of liquid addition is increased and stable. This is because the obtained liquid properties can be obtained.

  The method for preparing the coating solution for forming the high refractive index layer is not particularly limited. For example, the first metal oxide particles, the first water-soluble resin, and additives such as a surfactant added as necessary And stirring and mixing. At this time, the order of addition of the respective components is not particularly limited, and the respective components may be sequentially added and mixed while stirring, or may be added and mixed all at once while stirring. If necessary, it may be adjusted to an appropriate viscosity using a solvent.

  Moreover, when preparing the coating liquid for high refractive index layer formation, you may prepare it, heating suitably.

[Coating liquid for forming low refractive index layer]
The coating solution for forming a low refractive index layer preferably contains a second water-soluble resin and second metal oxide particles, and, if necessary, a group consisting of a curing agent, a surfactant, and various additives. You may further contain at least 1 sort selected from more.

  Since specific forms of the second water-soluble resin, the second metal oxide particles, the curing agent, the surfactant, and the various additives are as described above, description thereof is omitted here.

  In addition, it is preferable that the density | concentration of 2nd water-soluble resin in the coating liquid for low refractive index layer formation is 1-10 mass%, and it is more preferable that it is 1-8 mass%. Moreover, it is preferable that the density | concentration of a 2nd metal oxide particle is 1-50 mass% in a coating liquid for low refractive index layer formation, and it is more preferable that it is 2-20 mass%.

  As the solvent for preparing the coating solution for forming the low refractive index layer, the same solvent as the solvent for preparing the coating solution for forming the high refractive index layer described above can be used. .

  The method for preparing the coating solution for forming the low refractive index layer is not particularly limited, and the addition of the second water-soluble resin, the second metal oxide particles, and a curing agent or a surfactant added as necessary. The method of adding an agent and stirring and mixing is mentioned. At this time, the order of addition of the respective components is not particularly limited, and the respective components may be sequentially added and mixed while stirring, or may be added and mixed all at once while stirring. If necessary, it may be adjusted to an appropriate viscosity using a solvent.

  Moreover, when preparing the coating liquid for low refractive index layer formation, you may prepare it, heating suitably.

  Next, using the coating liquid for forming a high refractive index layer and the coating liquid for forming a low refractive index layer prepared as described above, it is applied onto a substrate and dried to form a dielectric multilayer film.

  The coating method is not particularly limited and may be either a sequential coating method or simultaneous multilayer coating, but simultaneous multilayer coating is preferable from the viewpoint of productivity and the like.

  As the coating method, for example, a curtain coating method, a slide bead coating method using a hopper described in U.S. Pat. Nos. 2,761,419 and 2,761,791, an extrusion coating method and the like are preferably used. It is done.

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

  The viscosity of the high refractive index layer coating solution and the low refractive index layer coating solution when performing simultaneous multilayer coating is not particularly limited. However, when the slide bead coating method is used, it is preferably in the range of 5 to 100 mPa · s and more preferably in the range of 10 to 50 mPa · s in the preferable temperature range of the coating solution. Moreover, when using a curtain application | coating system, it is preferable that it is the range of 5-1200 mPa * s in the range of the preferable temperature of said coating liquid, and it is more preferable that it is the range of 25-500 mPa * s. If it is the range of such a viscosity, simultaneous multilayer coating can be performed efficiently.

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

  Specific coating and drying methods are not particularly limited, but when a reflective film is formed by a sequential coating method, the coating solution for forming a low refractive index layer and the formation of a high refractive index layer heated to 30 to 60 ° C. One of the coating liquids for coating is applied on a substrate and dried to form a layer, and then the other coating liquid is coated on this layer and dried to form a layer. This is sequentially applied so that the number of layers required to exhibit the desired infrared shielding performance is obtained, thereby obtaining a precursor. When drying, it is preferable to dry the formed coating film at 30 ° C. or higher. For example, the wet bulb temperature is preferably 5 to 50 ° C. and the film surface temperature is preferably 5 to 100 ° C. (preferably 10 to 50 ° C.). For example, hot air of 40 to 85 ° C. is blown for 1 to 5 seconds. dry. As a drying method, warm air drying, infrared drying, and microwave drying are used. In addition, it is preferable to perform a multi-stage process rather than a single process, and it is more preferable that the temperature of the constant rate drying unit is less than the temperature of the rate-decreasing drying unit. In this case, the temperature range of the constant rate drying part is preferably 30 to 60 ° C, and the temperature range of the decreasing rate drying part is preferably 50 to 100 ° C.

  In addition, when forming a dielectric multilayer film by simultaneous multilayer coating, the coating liquid for forming a low refractive index layer and the coating liquid for forming a high refractive index layer are heated to 30 to 60 ° C. After the simultaneous multilayer coating of the coating solution for forming the refractive index layer and the coating solution for forming the high refractive index layer, the temperature of the formed coating film is preferably cooled (set) to preferably 1 to 15 ° C., and then 10 ° C. or higher. It is preferable to dry with. More preferable drying conditions are a wet bulb temperature of 5 to 50 ° C. and a film surface temperature of 10 to 50 ° C. For example, it is dried by blowing warm air of 80 ° C. for 1 to 5 seconds. Moreover, as a cooling method immediately after application | coating, it is preferable to carry out by a horizontal set system from a viewpoint of the uniformity improvement of the formed coating film.

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

  The time (setting time) from the time of application to the completion of setting by applying cold air is preferably within 5 minutes, and more preferably within 2 minutes. Further, the lower limit time is not particularly limited, but it is preferable to take 45 seconds or more. By setting the set time to a certain value or more, the components in the layer can be sufficiently mixed. On the other hand, by setting the setting time to a short time, it is possible to prevent interlayer diffusion of the metal oxide particles and to make a desired refractive index difference between the high refractive index layer and the low refractive index layer. In the case where high elasticity occurs quickly at the interface between the high refractive index layer and the low refractive index layer, a suitable interface can be formed without providing a setting step.

  In addition to changing the concentration of water-soluble resin and the concentration of metal oxide particles, the set time is added with other components such as various known gelling agents such as gelatin, pectin, agar, carrageenan and gellan gum. It can be adjusted by doing.

  The temperature of the cold air used in the setting step is preferably 0 to 25 ° C, and more preferably 5 to 10 ° C. The time for which the coating film is exposed to cold air is preferably 10 to 360 seconds, more preferably 10 to 300 seconds, and still more preferably 10 to 120 seconds, although it depends on the transport speed of the coating film.

  What is necessary is just to apply | coat so that the coating thickness of the coating liquid for high refractive index layer formation and the coating liquid for low refractive index layer formation may become the preferable thickness at the time of drying as shown above.

  When the optical reflective film according to the present invention is an infrared shielding film that reflects infrared light, it is possible to design a large difference in refractive index between the low refractive index layer and the high refractive index layer with a small number of layers. It is preferable from the viewpoint that the infrared reflectance can be increased. In this embodiment, in at least one of the laminated units composed of the low refractive index layer and the high refractive index layer, the difference in refractive index between the adjacent low refractive index layer and high refractive index layer may be 0.1 or more. Preferably, it is 0.3 or more, more preferably 0.35 or more, and particularly preferably 0.4 or more. In the case of having a plurality of laminated bodies of high refractive index layers and low refractive index layers, it is preferable that the refractive index difference between the high refractive index layer and the low refractive index layer in all the laminated bodies is within the above-mentioned preferable range. However, even in this case, the refractive index layers constituting the uppermost layer and the lowermost layer of the dielectric multilayer film may have a configuration outside the above preferred range.

  As an optical characteristic of the optical reflective film of the present embodiment, the transmittance in the visible light region shown in JIS R3106-1998 is preferably 50% or more, more preferably 75% or more, and further preferably 85% or more. is there. Moreover, it is preferable to have the area | region exceeding a reflectance of 50% in the area | region of wavelength 900nm-1400nm.

  From the above viewpoint, the number of refractive index layers of the dielectric multilayer film (total number of high refractive index layers and low refractive index layers) is, for example, 6 to 500 layers, and 6 to 300 layers. Is preferred. Moreover, when producing especially by a wet film forming method, it is preferable that it is 6-50 layers, It is more preferable that it is 8-40 layers, It is more preferable that it is 9-30 layers, It is 11-31 layers It is particularly preferred. It is preferable that the number of refractive index layers of the dielectric multilayer film is in the above range because excellent heat shielding performance and transparency, suppression of film peeling and cracking, and the like can be realized. In the case where the dielectric multilayer film has a plurality of high refractive index layers and / or low refractive index layers, each high refractive index layer and / or each low refractive index layer may be the same, It may be different.

  The thickness per layer of the high refractive index layer is preferably 20 to 800 nm, and more preferably 50 to 500 nm. Further, the thickness per layer of the low refractive index layer is preferably 20 to 800 nm, and more preferably 50 to 500 nm.

  Here, when measuring the thickness per layer, the composition may change continuously without having a clear interface at the boundary between the high refractive index layer and the low refractive index layer. In such an interface region where the composition changes continuously, when the maximum refractive index−minimum refractive index = Δn, the point where the minimum refractive index between two layers + Δn / 2 is regarded as the layer interface.

  In addition, when the high refractive index layer and the low refractive index layer contain metal oxide particles, the above composition can be observed from the concentration profile of the metal oxide particles. The metal oxide concentration profile is formed by etching from the surface to the depth direction using a sputtering method, and using an XPS surface analyzer, sputtering is performed at a rate of 0.5 nm / min, with the outermost surface being 0 nm. It can be seen by measuring the ratio. Further, the laminated film may be cut and the cut surface may be confirmed by measuring the atomic composition ratio with an XPS surface analyzer.

  The XPS surface analyzer is not particularly limited, and any model can be used. As the XPS surface analyzer, for example, ESCALAB-200R manufactured by VG Scientific, Inc. can be used. Mg is used for the X-ray anode, and measurement is performed at an output of 600 W (acceleration voltage: 15 kV, emission current: 40 mA).

[Hard coat layer]
In the present invention, the “hard coat layer” is a layer having a pencil hardness according to JIS K 5600-5-4 of HB or higher, preferably a layer of H or higher, more preferably a layer of 2H or higher. . The hardness of the hard coat layer is preferably in terms of scratch resistance as long as the layer is not damaged or peeled off when an external stress such as bending is applied.

  In the optical reflective film of the present invention, the thickness of the hard coat layer is preferably 1 to 5 μm, and more preferably 1.5 to 3 μm. By setting the film thickness of the hard coat layer within the above range, it becomes easy to achieve curl balance with the dielectric multilayer film. Moreover, if the film thickness of a hard-coat layer is 1 micrometer or more, sufficient hardness can be maintained, and if it is 5 micrometers or less, it can prevent that a hard-coat layer is cracked or deteriorated by stress. Furthermore, if the film thickness of the hard coat layer is 5 μm or less, higher visible light transmittance can be obtained. When the hard coat layer contains a resin composed of a polyfunctional urethane acrylate, particularly a hydroxyl group-containing polyfunctional urethane acrylate, as the ultraviolet curable resin, such a polyfunctional urethane acrylate has a relatively large dimensional change due to humidity change. It is preferable to set the film thickness of the hard coat layer to 2 μm or less because it becomes easy to control the fluctuation of the curl value due to the humidity change in the environment within a predetermined range.

  In the optical reflection film of the present invention, the ratio of the thickness of the hard coat layer to the thickness of the dielectric multilayer film (thickness of the hard coat layer / thickness of the dielectric multilayer film) is 0.2-2. It is preferable that it is 0.5 to 1.5. By setting the ratio of the thickness of the hard coat layer to the thickness of the dielectric multilayer film within the above range, it becomes easy to achieve curl balance with the dielectric multilayer film. As a result, an optical reflection film having better weather resistance can be obtained.

  There is no restriction | limiting in particular about the constituent material of a hard-coat layer, A conventionally well-known knowledge can be referred. For the hard coat layer, for example, an active energy ray curable resin can be used in addition to an inorganic material typified by a polysiloxane hard coat.

(Polysiloxane hard coat)
As the polysiloxane hard coat, a material represented by the general formula R _m Si (OR ′) _n is a starting material. R and R ′ represent an alkyl group having 1 to 10 carbon atoms, and m and n are integers satisfying the relationship of m + n = 4. Specifically, tetramethoxysilane, tetraethoxysilane, tetra-iso-propoxysilane, tetra-n-polopoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, terapentaethoxy Silane, tetrapenta-iso-propoxysilane, tetrapenta-n-propoxysilane, tetrapenta-n-butoxysilane, tetrapenta-sec-butoxysilane, tetrapenta-tert-butoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxy Silane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethylethoxysilane, dimethylmethoxysilane, dimethylpropoxysilane, dimethylbutoxysilane, dimethyl Dimethoxysilane, dimethyl diethoxy silane, hexyl trimethoxy silane and the like. In addition, 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 Propyltrilimethoxysilane, hexamethyldisilazane, vinyltris (β-methoxyethoxy) silane, and octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium chloride can also be used. A state in which a hydrolyzable group such as methoxy group or ethoxy group is substituted with a hydroxyl group is generally called a polyorganosiloxane hard coat. When this is applied on a substrate and cured by heating, the dehydration condensation reaction is promoted, and the hard coat layer is formed by curing and crosslinking. Among these polyorganosiloxane hard coats, those having an organic group that is not eliminated by hydrolysis are methyl groups have the highest weather resistance. Moreover, if it is a methyl group, since the methyl group is uniformly and densely distributed on the surface after the hard coat layer is formed, the falling angle is also low. Therefore, in this application, it is preferable to use methylpolysiloxane.

Specific examples of the polyorganosiloxane hard coat include Surcoat Series (manufactured by Doken), SR2441 (Toray Dow Corning), Perma-New ^TM 6000 (California Hardcoating Company), and the like.

(Active energy ray curable resin)
It is also preferable to use a resin component such as an active energy ray curable resin as a material for forming the hard coat layer. The active energy ray resin refers to a resin that is cured through a crosslinking reaction or the like by irradiation with active rays such as ultraviolet rays or electron beams. As the active energy ray curable resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and the active energy ray curable resin layer is cured by irradiation with an active ray such as an ultraviolet ray or an electron beam. It is formed. Typical examples of the active energy ray curable resin include an ultraviolet curable resin and an electron beam curable resin, and a resin curable by ultraviolet irradiation is preferable.

  As the ultraviolet curable resin, for example, 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 epoxy resin is preferable. Used. Among them, acrylates as shown below are preferable, and ultraviolet curable urethane acrylate resins are particularly preferable. In addition, these resin may be used independently and may be used in combination of 2 or more type.

  As used herein, the term “(meth) acrylate” means acrylate or methacrylate. In the present invention, the (meth) acrylate may be any of a monomer, an oligomer, and a prepolymer, and is not particularly limited. The (meth) acrylate may be a monofunctional (meth) acrylate or a bifunctional or higher polyfunctional (meth) acrylate, and may have a molecular structure having a polar group or a low-polar molecular structure. In the present invention, it is preferable to use a polyfunctional (meth) acrylate having 2 or more functional groups, particularly 3 or more functional groups, whereby the wear resistance of the hard coat layer can be improved. In addition, it is considered that the use of polyfunctional (meth) acrylate can make the polymer network structure more complex, and ensure the hardness and adhesion of the hard coat layer. These (meth) acrylates may be used alone or in combination of two or more.

  Examples of the polar group of the (meth) acrylate having a molecular structure having a polar group include a hydroxyl group, a carboxyl group, an amide group, and an amino group. Examples of the hydroxyl group-containing (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, Such as 2- (meth) acryloyloxyethyl-2-hydroxypropyl phthalate, glycerol mono (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, etc. Examples include (meth) acrylic acid hydroxyalkyl esters. Examples of the carboxyl group-containing (meth) acrylate include, for example, ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid, 2- (meth) acryloyloxyethyl succinic acid, Examples include 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, and the like. Examples of amide group-containing (meth) acrylates include acrylamides such as (meth) acrylamide, N-methyl (meth) acrylamide, and N-methylol (meth) acrylamide. Examples of amino group-containing or other (meth) acrylates include, for example, monomethylaminoethyl (meth) acrylate, monoethylaminoethyl (meth) acrylate, monomethylaminopropyl (meth) acrylate, monoethylamino (meth) acrylate In addition to (meth) acrylic acid monoalkylamino esters such as propyl, diethylaminoethyl (meth) acrylate, dimethylaminomethyl (meth) acrylate and the like can be mentioned.

  Examples of the (meth) acrylate having a low polar molecular structure include alicyclic and non-alicyclic ones. Examples of the alicyclic (meth) acrylate include cyclohexyl acrylate, isobornyl acrylate, dicyclopentenyloxyethyl acrylate, dicyclopentadienyl acrylate, tricyclodecanyl acrylate, norbornyl acrylate, and the like. Examples of other (meth) acrylates include lauryl acrylate, 2-ethylhexyl acrylate, isodecyl acrylate, benzyl acrylate, stearyl acrylate, 1,6-hexanediol acrylate, butyl acrylate, and styrene monomer.

  As the (meth) acrylate monomer constituting the (meth) acrylate, only one kind may be used alone, or two or more kinds may be used in combination. Among these, the skeleton structure has a cyclic structure. It is preferable to contain a thing. The cyclic structure may be a carbocyclic structure or a heterocyclic structure, and may be a monocyclic structure or a polycyclic structure.

  Examples of polyfunctional (meth) acrylate monomers include pentaerythritol di (meth) acrylate, pentaerythritol tri and tetraacrylate, dipentaerythritol penta and hexaacrylate, diethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate. Polyfunctional (meth) acrylates such as tetramethyloltetra (meth) acrylate can be preferably used. Further, for example, those having an isocyanurate structure such as di (acryloxyethyl) isocyanurate, tris (acryloxyethyl) isocyanurate, dimethylol dicyclopentane diacrylate, ethylene oxide-modified hexahydrophthalic acid diacrylate, tricyclode Candimethanol acrylate, neopentyl glycol-modified trimethylolpropane diacrylate, adamantane diacrylate, and the like are suitable.

  The (meth) acrylate monomer constituting the ultraviolet curable resin may be a (meth) acrylate oligomer. Examples of such (meth) acrylate oligomers include polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate (also referred to as “urethane acrylate”), and polyether (meth) acrylate. , Polybutadiene (meth) acrylates, silicone (meth) acrylates, and the like.

  In the present invention, the hard coat layer preferably contains an ultraviolet curable urethane acrylate resin. The urethane acrylate constituting the ultraviolet curable urethane acrylate resin is generally obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer and further adding 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate (hereinafter referred to as acrylate). Can be easily obtained by reacting an acrylate monomer having a hydroxyl group such as 2-hydroxypropyl acrylate. For example, a mixture of 100 parts Unidic 17-806 (manufactured by Dainippon Ink Co., Ltd.) and 1 part of Coronate L (manufactured by Nippon Polyurethane Co., Ltd.) described in JP-A-59-151110 is preferably used. It is done. Commercially available products may be used as the UV curable urethane acrylate resin, and as commercial products, Beamset (registered trademark) 575, 577 (manufactured by Arakawa Chemical Industry Co., Ltd.), Shikou (registered trademark) UV series, etc. Can be mentioned. In the present specification, the urethane acrylate may be any of a monomer, an oligomer, and a prepolymer, and is not particularly limited.

  The glass transition point of urethane acrylate is preferably 40 to 100 ° C, more preferably 40 to 90 ° C, and particularly preferably 40 to 80 ° C. By setting the glass transition point of urethane acrylate within the above range, the coating film hardness and wear resistance at room temperature are improved. When the glass transition point of urethane acrylate is 40 ° C. or higher, the wear resistance and coating film hardness of the hard coat layer can be improved. If the glass transition point is 100 ° C. or lower, the coating film hardness becomes too high and the problem of cracking during molding hardly occurs. Here, the glass transition point of urethane acrylate refers to a value measured by a differential scanning calorimetry (DSC) method.

  The pencil hardness of the ultraviolet curable urethane acrylate resin is preferably 3B or more, more preferably 2B or more, and particularly preferably B or more. By setting the pencil hardness of the ultraviolet curable urethane acrylate resin within the above range, there is an advantage that the hardness of the hard coat layer is improved and the wear resistance is improved.

The pencil hardness of the UV curable urethane acrylate resin is such that a composition comprising urethane acrylate and a photopolymerization initiator is applied on a glass substrate, and the irradiation distance is 20 cm from the composition side with a high-pressure mercury lamp (80 mW / cm ² ). It refers to the value measured by JIS K5400 (load 500 g) on a 10 μm thick film cured under the condition of irradiating with ultraviolet rays at 800 mJ / cm ² .

  The functional group of the urethane acrylate may be monofunctional or polyfunctional with 2 or more functions, but is preferably 2 to 8 functions, more preferably 2 to 6 functions, and more preferably 2 to 3 functions. It is particularly preferred that By using 2-8 functional urethane acrylate, there is a merit that the balance of hardness and elongation rate of the hard coat layer is stabilized. By balancing the hardness and elongation rate of the hard coat layer, the wear resistance of the hard coat layer is improved and cracking during molding is less likely to occur. In addition, it is considered that the use of a bifunctional or higher polyfunctional urethane acrylate can make the polymer network structure more complex and ensure the hardness and adhesion of the hard coat layer. Urethane acrylates may be used alone or in combination of two or more.

  The urethane acrylate constituting the ultraviolet curable urethane acrylate resin particularly preferably contains a hydroxyl group-containing polyfunctional urethane acrylate synthesized from acrylic acid or methacrylic acid having a diisocyanate and a polyhydric alcohol. Examples of the ultraviolet curable urethane acrylate resin containing a hydroxyl group-containing polyfunctional urethane acrylate include Beamset (registered trademark) 575 and 577 (manufactured by Arakawa Chemical Co., Ltd.), EBECRYL 8210 (manufactured by Daicel Ornex Corporation), and the like. be able to. By containing a hydroxyl group, the adhesion to the substrate is enhanced by hydrogen bonding, so that the hard coat adhesion is maintained even when placed in an environment where the temperature and humidity change for a long time. The effect can be improved.

  The ratio of the hydroxyl group-containing polyfunctional urethane acrylate in 100% by mass of the resin component of the hard coat layer is not particularly limited, but is preferably in the range of 10 to 90% by mass, and in the range of 15 to 60% by mass. Is more preferable. When the amount of the hydroxyl group-containing polyfunctional urethane acrylate in the resin component of the hard coat layer is 10% by mass or more, the wear resistance of the layer can be improved while maintaining the flexibility of the hard coat layer. Further, if the amount of the hydroxyl group-containing polyfunctional urethane acrylate contained in the hard coat layer is 90% by mass or less, the flexibility of the layer can be improved while maintaining the wear resistance and the coating film hardness of the hard coat layer. it can.

  Moreover, as a particularly preferable embodiment when the hard coat layer contains a resin component, the ratio of the hydroxyl group-containing polyfunctional urethane acrylate in 100% by mass of the resin component is preferably 50% by mass or more. This ratio is more preferably 50 to 90% by mass, and further preferably 60 to 85% by mass. By setting it as such a structure, the advantage that the adhesiveness of a base material and a hard-coat layer improves is acquired.

(Photopolymerization initiator)
When a resin component such as an active energy ray curable resin is used as a material for forming the hard coat layer, the hard coat layer can contain a photopolymerization initiator. By containing a photopolymerization initiator, the polymerization and curing reaction of the hard coat layer by irradiation with active energy rays (ultraviolet rays) can be performed in a short time.

  Examples of the photopolymerization initiator include benzophenone, benzyl, Michler's ketone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-diethoxyacetophenone, benzyldimethyl ketal, 2 , 2-Dimethoxy-1,2-diphenylethane-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- ( Methylthio) phenyl] -2-morpholinopropanone-1, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, bis (cyclopentadienyl) ) -Bis (2,6-difluo) -3- (pyr-1-yl) titanium, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis ( 2,4,6-trimethylbenzoyl) phenylphosphine oxide, etc. These compounds may be used alone or in combination.

  The photopolymerization initiator contained in the solid content of the hard coat layer is preferably 0.01 to 10% by mass and more preferably 0.1 to 7% by mass in the total solid content of the hard coat layer. It is particularly preferable that 0.1 to 5% by mass is blended. If the content of the photopolymerization initiator is 0.01% by mass or more, sufficient photocurability can be obtained. Moreover, if content of a photoinitiator is 10 mass% or less, generation | occurrence | production of coloring of a hard-coat layer can be suppressed.

  Moreover, when using a photoinitiator, in order to improve photocurability, it is also possible to add well-known various dyes and a sensitizer. Further, a thermal polymerization initiator capable of curing the hard coat layer by heating can be used in combination with the photopolymerization initiator. In this case, it can be expected to further accelerate polymerization and curing of the hard coat layer by heating after photocuring.

  The thermal polymerization initiator is not particularly limited, and includes those that decompose by heat and generate active radicals that initiate polymerization and curing. For example, dicumyl peroxide, di-t-butyl peroxide, t-butyl peroxybenzoyl, t-butyl hydroperoxide, benzoyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramentane hydroperoxide Di-t-butyl peroxide and the like can be used. Moreover, as what is marketed among thermal polymerization initiators, for example, perbutyl D, perbutyl H, perbutyl P, permenta H (all manufactured by NOF Corporation) and the like are preferably used. These thermal polymerization initiators may be used independently and 2 or more types may be used together.

((Meth) acrylic modified silicone compound)
In the optical reflective film of the present invention, the hard coat layer may contain a (meth) acryl-modified silicone compound. Here, the “(meth) acryl-modified silicone compound” means a (meth) acryl group at an arbitrary position (preferably terminal (one terminal or both terminals), more preferably both terminals) such as a side chain or terminal of the silicone skeleton. As a compound itself, a conventionally known compound can be appropriately used. Specific examples of the (meth) acryl-modified silicone compound include TEGORad2010 / Rad2011 (manufactured by EVONIC), SQ100 / SQ200 (manufactured by Tokushiki), CN990 / CN9800 (manufactured by Sartomer), EBECRYL350 (manufactured by Daicel Ornex), X -22-2445 / X-22-1602 (Both-terminal acrylate silicon), X-22-164 / X-22-164AS / X-22-164A / X-22-164B / X-22-164C / X-22 -164E (both ends methacrylate silicon), X-22-174ASX / X-22-174BX / KF-2012 / X-22-2426 / X-22-2475 (single end methacrylate silicon) (above, manufactured by Shin-Etsu Chemical Co., Ltd.) ), BYK UV-3500 / BYK UV 3570 (manufactured by BYK Japan KK), and the like. Further, (meth) acryloxypropyl-terminated polydimethylsiloxane, [(meth) acryloxypropyl] methylsiloxane, a copolymer of [(meth) acryloxypropyl] methylsiloxane and dimethylsiloxane, and the like can also be used. In addition, those in which a methyl group is introduced at the terminal of the (meth) acryl group of these compounds can also be used. The number of functional groups in one molecule is preferably 2 or more, but one having 1 functional group may be used. The functional group equivalent is preferably in the range of 100 to 1000. Within this range, the tackiness of the obtained hard coat layer and the heat resistance of the cured product are improved.

  The content of the (meth) acryl-modified silicone compound contained in the hard coat layer is, for example, 0.001 to 3% by mass. When the content of the (meth) acryl-modified silicone compound is 0.001% by mass or more, the occurrence of cracks and a decrease in scratch resistance due to coating defects such as repellency and dents can be sufficiently suppressed. On the other hand, if the content of the (meth) acryl-modified silicone compound is 3% by mass or less, the hard coat layer is hardly broken and cracks are hardly generated. The content of the (meth) acryl-modified silicone compound contained in the hard coat layer is more preferably 0.01 to 1% by mass, and still more preferably 0.03 to 0.5% by mass.

(Infrared absorbing metal oxide nanoparticles)
The hard coat layer preferably contains infrared absorbing metal oxide nanoparticles that absorb infrared rays. By setting it as such a structure, the infrared shielding effect of an optical reflection film can be improved. Moreover, when the hard coat layer contains infrared-absorbing metal oxide nanoparticles, the adhesion of the hard coat layer to the substrate can be improved, and the scratch resistance of the optical reflective film can be improved. In addition, it has the property of absorbing ultraviolet rays and converting it into heat, which is considered to increase the adhesion of the hard coat layer and give the effect of suppressing the occurrence of cracks. In the present invention, the “nanoparticle” means a particle having an average (primary) particle size of 1000 nm or less, more preferably having an average particle size in the range of 1 to 500 nm, and in the range of 1 to 100 nm. More preferred. By being a nanoparticle as described above, the visible light transmittance of the hard coat layer is ensured. The particle diameter means the maximum distance among the distances between any two points on the outline of the particle (observation surface) observed using an observation means such as a transmission electron microscope. As the value of the average particle diameter, a value calculated as the number average value of the particle diameters of particles observed in several to several tens of fields using an observation means such as a transmission electron microscope is used.

Since the infrared-absorbing metal oxide nanoparticles are nanoparticles, the visible light transmittance of the hard coat layer is ensured. Such infrared absorbing metal oxide nanoparticles include tin, antimony, indium, titanium, silicon, aluminum, zirconium, boron, cerium, tungsten, nickel, vanadium, and zinc oxides and doped oxides, and These mixtures are mentioned. More specifically, tin oxide, antimony oxide, indium oxide, indium doped tin oxide (ITO), antimony doped indium tin oxide, antimony tin oxide, antimony doped tin oxide (ATO), titanium oxide, zinc oxide, Antimony-doped zinc oxide (AZO), indium-doped zinc oxide (IZO), gallium-doped zinc oxide (GZO), aluminum-doped zinc oxide, silicon oxide, alumina, zirconia, lanthanum boride, cerium oxide, vanadium oxide, Examples include nickel oxide, tungsten oxide, cesium doped tungsten oxide (CWO), or a mixture thereof. In addition, oxide nanoparticles containing Cd / Se, GaN, Y ₂ O ₃ , Au, Ag, and Cu can also be used.

  In addition, in this specification, the compound doped with another metal means both a state where another metal is mixed in the compound or a state where the compound and another metal (oxide) are bonded. Point to.

  The compounding amount of the infrared absorbing metal oxide nanoparticles is preferably 20 to 50% by mass, and preferably 30 to 40% by mass with respect to the total amount of the constituent components of the hard coat layer (solid content conversion). More preferred. When the content of the infrared-absorbing metal oxide nanoparticles is in such a range, it becomes easy to achieve both hard coat properties and infrared light shielding properties. Moreover, if the compounding quantity of an infrared absorptive metal oxide nanoparticle is 20 mass% or more, the adhesiveness of a hard-coat layer will be improved and the effect which prevents generation | occurrence | production of a crack will be high. On the other hand, if the blending amount of the infrared-absorbing metal oxide nanoparticles is 50% by mass or less, the brittleness of the hard coat layer is difficult to be lowered, so that the occurrence of cracks due to dimensional changes can be suppressed. Moreover, a higher visible light transmittance can be obtained in the optical reflection film.

  The hard coat layer preferably contains the infrared-absorbing metal oxide nanoparticles as described above, but from the viewpoint of weather resistance and absorption spectrum, other infrared absorptions other than the nanoparticles unless the effects of the present invention are impaired. You may mix and use an agent. For example, lanthanum boride, nickel complex compounds, imonium compounds, phthalocyanine compounds, and aminium compounds can be used. The blending amount of the other infrared absorber in the hard coat layer is preferably 5% by mass or less, more preferably 3% by mass or less, and most preferably 0% by mass.

  The hard coat layer is preferably a layer formed by curing a composition containing a hydroxyl group-containing polyfunctional urethane acrylate, a photopolymerization initiator, and infrared absorbing metal oxide nanoparticles. By setting it as such a hard-coat layer, the effect which improves a weather resistance and adhesiveness can improve.

  There is no restriction | limiting in particular about the formation method of a hard-coat layer, It can form by methods, such as coating by a wire bar, spin coating, and application | coating by dip coating. It can also be formed by a dry film forming method such as vapor deposition. Further, it is possible to apply and form a film using a continuous coating apparatus such as a die coater, a gravure coater, or a comma coater. In the case of a polysiloxane hard coat, after coating, the solvent is dried, and then heat treatment is performed at a temperature of 50 ° C. or higher and 150 ° C. or lower for 30 minutes to several days in order to promote curing and crosslinking of the hard coat. I need. On the other hand, in the case of an active energy ray curable resin, the reactivity changes depending on the irradiation wavelength, the illuminance, and the light amount of the active energy ray, so it is necessary to select the optimum conditions depending on the resin to be used.

  Especially, it is preferable that a hard-coat layer is formed by apply | coating the coating liquid containing an organic solvent, and making it dry. By using a coating solution containing an organic solvent, it is possible to further reduce coating defects such as repellency and dents when coated on a substrate. As a result, it becomes easy to prevent the deterioration of scratch resistance and the occurrence of cracks due to these coating defects.

[Other layers]
(Middle layer)
The optical reflective film according to the present invention may have a layer (other layers) other than the layers described above. For example, an intermediate layer can be provided as the other layer. Here, the “intermediate layer” means a layer between the base material and the dielectric multilayer film, or a layer between the base material and the hard coat layer. Examples of the constituent material of the intermediate layer include polyester resin, polyvinyl alcohol resin, polyvinyl acetate resin, polyvinyl acetal resin, acrylic resin, urethane resin, and the like. Any of them may be used as long as they are satisfied. The glass transition temperature (Tg) of the intermediate layer is preferably 30 to 120 ° C because sufficient weather resistance can be obtained, and more preferably in the range of 30 to 90 ° C.

(Adhesive layer)
Moreover, the optical reflection film according to the present invention may have an adhesive layer. This pressure-sensitive adhesive layer is usually provided on the surface of the dielectric multilayer film opposite to the substrate, and a known release paper or separator may be further provided. The configuration of the adhesive layer is not particularly limited, and for example, any of a dry laminating agent, a wet laminating agent, an adhesive, a heat seal agent, a hot melt agent, and the like is used.

  Examples of the pressure-sensitive adhesive include polyester-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, polyvinyl acetate-based pressure-sensitive adhesives, acrylic pressure-sensitive adhesives, and nitrile rubber.

  When the optical reflective film of the present invention is bonded to a window glass, water is sprayed on the window, and a method of applying the adhesive layer of the optical reflective film to the wet glass surface, the so-called water pasting method is repositioned, repositioned, etc. From the viewpoint of, it is preferably used. For this reason, an acrylic pressure-sensitive adhesive that has a weak adhesive force in the presence of water is preferably used.

  The acrylic pressure-sensitive adhesive used may be either solvent-based or emulsion-based, but is preferably a solvent-based pressure-sensitive adhesive because it is easy to increase the adhesive strength and the like, and among them, those obtained by solution polymerization are preferable. As a raw material when producing such a solvent-based acrylic pressure-sensitive adhesive by solution polymerization, for example, as a main monomer serving as a skeleton, an acrylic ester such as ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, acryl acrylate, As a comonomer to improve cohesive strength, vinyl acetate, acrylonitrile, styrene, methyl methacrylate, etc., to further promote crosslinking, to give stable adhesive strength, and to maintain a certain level of adhesive strength even in the presence of water Examples of the functional group-containing monomer include methacrylic acid, acrylic acid, itaconic acid, hydroxyethyl methacrylate, and glycidyl methacrylate. Since the adhesive layer requires a particularly high tack property as the main polymer, those having a low glass transition temperature (Tg) such as butyl acrylate are particularly useful.

  As a commercial item of the said acrylic adhesive, Coponyl series (made by Nippon Synthetic Chemical Co., Ltd.) etc. are mentioned, for example.

  This adhesive layer contains additives such as stabilizers, surfactants, UV absorbers, flame retardants, antistatic agents, antioxidants, thermal stabilizers, lubricants, fillers, coloring, adhesion modifiers, etc. It can also be made. In particular, when used for window sticking, the addition of an ultraviolet absorber is effective in order to suppress deterioration of the optical reflection film due to ultraviolet rays.

  The adhesive coating method is not particularly limited, and any known method can be used. For example, a bar coating method, a die coater method, a gravure roll coater method, a blade coater method, a spray coater method, an air knife coating method. A dip coating method, a transfer method, and the like are preferably mentioned, and they can be used alone or in combination. These can be appropriately formed into a solution in a solvent capable of dissolving the pressure-sensitive adhesive, or can be applied using a dispersed coating solution, and known solvents can be used.

  Moreover, it is preferable that the thickness of an adhesion layer is the range of about 1-100 micrometers normally from viewpoints, such as an adhesion effect and a drying rate.

  The adhesive strength is preferably 2 to 30 N / 25 mm, more preferably 4 to 20 N / 25 mm, as measured by a 180 ° peel test described in JIS K6854.

  The adhesive layer may be formed directly on the dielectric multilayer film by the previous coating method. Alternatively, the adhesive layer may be applied to a release film and dried, and then the dielectric multilayer film is bonded. The adhesive may be transferred. The drying temperature at this time is preferably such that the residual solvent is reduced as much as possible. For this purpose, the drying temperature and time are not specified, but preferably a drying time of 10 seconds to 5 minutes is provided at a temperature of 50 to 150 ° C. Is good. In addition, since the adhesive has fluidity, the reaction is not yet completed immediately after drying by heating, and curing is necessary to complete the reaction and obtain a stable adhesive force. In general, when heated at room temperature for about one week or longer, for example, about 50 ° C. is preferably 3 days or longer. In the case of heating, if the temperature is raised too much, the flatness of the plastic film may be deteriorated.

[Method for producing optical reflection film]
There is no restriction | limiting in particular about the manufacturing method of an optical reflection film, A conventionally well-known knowledge can be referred suitably. Here, since the formation method of the dielectric multilayer film itself and the formation method of the hard coat layer itself have already been described above, detailed description thereof is omitted here.

  The optical reflective film according to the present invention is preferably one in which a dielectric multilayer film is formed on one surface of a substrate, and then a hard coat layer is formed on the other surface of the substrate.

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

≪Preparation of optical reflective film≫
<Example 1>
(Preparation of dielectric multilayer film)
A dielectric multilayer film containing 107 layers was produced on a continuous flat film production line by coextrusion.

  The dielectric multilayer film is a PMMA copolymer (coPMMA) (Perspex CP63 manufactured by Ineos Acrylics, Inc.) formed from 75% by mass of methyl methacrylate (MMA) monomer and 25% by mass of ethyl acrylate (EA) monomer. ) And PMMA (manufactured by Eastman Chemicals). Using the feedblock method, a 106-layer dielectric multilayer film having a nearly linear layer thickness gradient from layer to layer was made through the extrudate. PMMA was supplied to the feed block by an extruder at a flow rate of about 20 kg / hour and coPMMA was about 26 kg / hour.

  A portion of coPMMA was used as a protective boundary layer on each side of the extrudate at a total flow rate of 5 kg / hour. The material flow was then passed through an asymmetric doubler multiplier with a multiplication design ratio of 1.25. The multiplication ratio is defined by dividing the average film thickness of the layer generated in the main flow pipe by the average film thickness of the layer in the sub flow pipe. This multiplication ratio was chosen to slightly overlap the two reflection bands produced by the two sets of 53 optical layers. Each set of 53 optical layers has a similar layer thickness profile produced by the feedblock, and its overall thickness scale factor depends on its multiplier and film extrusion rate. After multiplication, 20 kg / hour of PET supplied from the third extruder as a base material was added as a skin layer. This stream of material was then transferred through a film die to a water-cooled casting wheel.

  The coPMMA melting process equipment was maintained at about 260 ° C., the PMMA melting process equipment was maintained at about 274 ° C., and the feedback, multiplier, skin layer melt stream, and die were maintained at about 274 ° C. The feedblock used for film preparation was designed to have a linear layer thickness distribution with the ratio of 1.3: 1 between the thickest and thinnest layers under isothermal conditions. The speed of the casting wheel was adjusted for precise control of the final film thickness and hence the final band edge position.

  The water temperature at the inlet of the casting wheel was about 7 ° C. The extrudate was pinned to the casting wheel using a high voltage pinning system. The pinned wire had a diameter of about 0.17 mm and a voltage of about 6.5 kV was applied. The pinning wire was positioned about 3-5 mm from the web at the point of contact with the casting wheel to give the cast web a smooth appearance. The cast web was continuously oriented by conventional sequential length orienter and tenter equipment. The web was longitudinally oriented at about 132 ° C. to a stretch ratio of about 3.8. This film was preheated to about 124 ° C. in a tenter for about 15 seconds and stretched in the width direction at about 132 ° C. to a stretch ratio of about 2.0. The film was heat set in a tenter furnace at a temperature of about 238 ° C. for about 30 seconds.

  A polyethylene terephthalate (PET) film is prepared as a base material. A coating solution for forming an adhesive layer, which will be described later, is applied on the PET film with a die coater and dried at 80 ° C. as an adhesive layer. And PET which is the skin layer of the laminate produced above were adhered. The produced film had a final thickness of about 25 μm, and the thickness of the dielectric multilayer film was 2.4 μm.

(Preparation of hard coat layer forming coating solution 1)
A coating liquid 1 for forming a hard coat layer having the following composition was prepared:
BLEMMER LA (manufactured by NOF Corporation) 1440 parts by mass BLEMMER CHA (manufactured by NOF Corporation) 1439.1 parts by mass Irgacure 184 (manufactured by BASF Japan Ltd.) 60 parts by mass Irgacure 819 (manufactured by BASF Japan Ltd.) 60 parts by mass MegaFuck F-552 (manufactured by DIC Corporation) 0.9 parts by mass.

(Preparation of adhesive layer forming coating solution)
3% by mass of coronate L-55E (manufactured by Nippon Polyurethane Industry Co., Ltd.) as a curing agent is added to coponil N-6694M (manufactured by Nippon Gosei Kagaku Co., Ltd.) as an adhesive, and tinuvin as a UV absorber. 5 mass% of 477 (made by BASF Japan Ltd.) was added, it diluted so that solid content might be 10 mass% with the ethyl acetate as a solvent, and the coating liquid for adhesion layer formation was prepared.

(Preparation of optical reflection film 1)
On the exposed surface side of the PET film laminated with the dielectric multilayer film produced above, the hard coat layer forming coating solution 1 prepared above is applied by a gravure coating method to form a coating film. Then, ultraviolet rays were irradiated for 1 second from a distance of 5 cm with an ultraviolet lamp with an output of 160 W / cm to cure the coating film to form a hard coat layer having a dry film thickness of 6 μm.

Furthermore, using the die coater, the adhesive layer forming coating solution prepared above was applied to a separator (NS-23MA: manufactured by Nakamoto Pax Co., Ltd.), dried at 80 ° C., and then the dielectric multilayer film prepared above was used. The surface and the surface of the pressure-sensitive adhesive layer were bonded together to produce an optical reflection film 1 having an internal bonding configuration (that is, a configuration bonded to the indoor side of a window glass or the like). The film thickness of the adhesive layer of the optical reflection film 1 was 10 μm. At this time, the amount of tinuvin 477 which is an ultraviolet absorber in the adhesive layer was 600 mg / m ² .

<Example 2>
In the production of the dielectric multilayer film, the number of layers to be co-extruded by the feed block method was set to 149 layers, so that a dielectric multilayer film having a final thickness of 3.3 μm was produced, and for forming a hard coat layer An optical reflective film 2 was produced in the same manner as in Example 1 except that the coating thickness of the coating liquid 1 was changed so that the dry thickness of the hard coat layer was 0.5 μm.

<Example 3>
(Preparation of hard coat layer forming coating solution 2)
A coating liquid 2 for forming a hard coat layer having the following composition was prepared:
BLEMMER LA (manufactured by NOF Corporation) 240 parts by mass Aronix M-350 (manufactured by Toagosei Co., Ltd.) 1200 parts by mass Aronix M-309 (manufactured by Toagosei Co., Ltd.) 1439.1 parts by mass Irgacure 184 (manufactured by BASF Japan Ltd.) ) 60 parts by mass Irgacure 819 (manufactured by BASF Japan Ltd.) 60 parts by mass Megafac F-552 (manufactured by DIC Corporation) 0.9 parts by mass.

  In Example 2, in place of the hard coat layer forming coating liquid coating liquid 1, the above-described implementation was performed except that the hard coat layer forming coating liquid coating liquid 2 was used to form the hard coat layer. The optical reflection film 3 was produced in the same procedure as in Example 2.

<Example 4>
In the production of the dielectric multilayer film, the number of layers to be co-extruded by the feed block method is 297 layers, so that the dielectric multilayer film having a final thickness of 6.7 μm is produced, and the hard coat layer is formed. An optical reflective film 4 was produced in the same manner as in Example 1 except that the coating thickness of the coating solution 1 was changed so that the dry thickness of the hard coat layer was 1 μm.

<Example 5>
In the production of the dielectric multilayer film, an optical reflection film 5 was produced in the same manner as in Example 4 except that the stretch ratio was changed as follows.

  The web was longitudinally oriented at about 132 ° C. to a draw ratio of about 2.0. The film was preheated to about 124 ° C. in a tenter for about 15 seconds and stretched in the width direction at about 132 ° C. to a stretch ratio of about 3.8.

<Example 6>
In the production of the dielectric multilayer film, the number of layers to be co-extruded by the feed block method was 89, so that a dielectric multilayer film having a final thickness of 2.0 μm was produced, and for hard coat layer formation An optical reflection film 6 was produced in the same manner as in Example 1 except that the coating thickness of the coating liquid 1 was changed so that the dry thickness of the hard coat layer was 5 μm.

<Example 7>
In the production of the dielectric multilayer film, the number of layers to be co-extruded by the feed block method was 37, so that a dielectric multilayer film having a final thickness of 0.8 μm was produced, and for forming a hard coat layer An optical reflective film 7 was produced in the same manner as in Example 1 except that the coating thickness of the coating solution 1 was changed so that the dry thickness of the hard coat layer was 2 μm.

<Example 8>
In the production of the dielectric multilayer film, the number of layers to be co-extruded by the feed block method was set to 45, so that a dielectric multilayer film having a final thickness of 1.0 μm was produced, and for hard coat layer formation An optical reflective film 8 was produced in the same manner as in Example 1 except that the coating thickness of the coating liquid 1 was changed so that the dry thickness of the hard coat layer was 2 μm.

<Example 9>
In the production of the dielectric multilayer film, the number of layers to be co-extruded by the feed block method was 89, so that a dielectric multilayer film having a final thickness of 2.0 μm was produced, and for hard coat layer formation An optical reflective film 9 was produced in the same manner as in Example 1 except that the coating thickness of the coating liquid 1 was changed so that the dry thickness of the hard coat layer was 2 μm.

<Example 10>
In the production of the dielectric multilayer film, the number of layers to be co-extruded by the feed block method is 447 layers, so that a dielectric multilayer film having a final thickness of 10.0 μm is produced, and for forming a hard coat layer An optical reflective film 10 was produced in the same manner as in Example 1 except that the coating thickness of the coating solution 1 was changed so that the dry thickness of the hard coat layer was 2 μm.

<Example 11>
(Preparation of coating liquid 3 for forming a hard coat layer)
A coating liquid 3 for forming a hard coat layer having the following composition was prepared:
Aronix M-305 (manufactured by Toagosei Co., Ltd.) 1200 parts by mass Beam set 577 (manufactured by Arakawa Chemical Industries, Ltd.) 1439.1 parts by mass Irgacure 184 (manufactured by BASF Japan Ltd.) 60 parts by mass Irgacure 819 (manufactured by BASF Japan Ltd.) ) 60 parts by mass Megafac F-552 (manufactured by DIC Corporation) 0.9 parts by mass.

  In Example 6, instead of the hard coat layer forming coating solution 1, the hard coat layer forming coating solution 3 prepared above was used, and the coating thickness was set so that the dry thickness of the hard coat layer was 2 μm. An optical reflective film 11 was produced in the same procedure as in Example 6 except that a hard coat layer was produced by applying to the above.

<Example 12>
(Preparation of hard coat layer forming coating solution 4)
A coating solution 4 for forming a hard coat layer having the following composition was prepared:
Aronix M-305 (manufactured by Toagosei Co., Ltd.) 1140 parts by mass Beam set 577 (manufactured by Arakawa Chemical Industries, Ltd.) 1439.1 parts by mass Irgacure 184 (manufactured by BASF Japan Ltd.) 60 parts by mass Irgacure 819 (manufactured by BASF Japan Ltd.) ) 60 parts by mass Megafac F-552 (manufactured by DIC Corporation) 0.9 parts by mass ATO methyl isobutyl ketone (MIBK) dispersion (solid content 35%; manufactured by Advanced Nano Products) 857.14 parts by mass.

  In Example 11, optical reflection was performed in the same procedure as in Example 11 except that the hard coat layer forming coating solution 4 prepared above was used instead of the hard coat layer forming coating solution 3. Film 12 was produced.

<Example 13>
(Preparation of hard coat layer forming coating solution 5)
A coating liquid 5 for forming a hard coat layer having the following composition was prepared:
Aronix M-305 (manufactured by Toagosei Co., Ltd.) 543.27 parts by mass Beam set 577 (manufactured by Arakawa Chemical Industries, Ltd.) 685.83 parts by mass Irgacure 184 (manufactured by BASF Japan Ltd.) 60 parts by mass Irgacure 819 (BASF Japan shares) 60 parts by mass Megafac F-552 (manufactured by DIC Corporation) 0.9 parts by mass MIBK dispersion of ATO (solid content 35%; manufactured by Advanced Nano Products) 4714.29 parts by mass.

  In Example 11, optical reflection was performed in the same procedure as in Example 11 except that the hard coat layer forming coating solution 5 prepared above was used instead of the hard coat layer forming coating solution 3. Film 13 was produced.

<Example 14>
(Preparation of hard coat layer forming coating solution 6)
A coating liquid 6 for forming a hard coat layer having the following composition was prepared:
Aronix M-305 (manufactured by Toagosei Co., Ltd.) 100.37 parts by mass Beam set 577 (manufactured by Arakawa Chemical Industries, Ltd.) 1271.70 parts by mass Irgacure 184 (manufactured by BASF Japan Ltd.) 60 parts by mass Irgacure 819 (BASF Japan stock) 60 parts by mass Megafac F-552 (manufactured by DIC Corporation) 0.9 parts by mass 1714.29 parts by mass of ATO MIBK dispersion (solid content 35%; manufactured by Advanced Nano Products).

  In Example 11, optical reflection was performed in the same procedure as in Example 11 except that the hard coat layer forming coating solution 6 prepared above was used instead of the hard coat layer forming coating solution 3. Film 14 was produced.

<Example 15>
(Preparation of hard coat layer forming coating solution 7)
A coating liquid 7 for forming a hard coat layer having the following composition was prepared:
Aronix M-305 (manufactured by Toagosei Co., Ltd.) 609.58 parts by mass Beam set 577 (manufactured by Arakawa Chemical Industries, Ltd.) 769.53 parts by mass Irgacure 184 (manufactured by BASF Japan Ltd.) 60 parts by mass Irgacure 819 (BASF Japan shares) 60 parts by mass Megafac F-552 (manufactured by DIC Corporation) 0.9 parts by mass MIBK dispersion of ATO (solid content 35%; manufactured by Advanced Nano Products) 4285.71 parts by mass.

  In Example 11, optical reflection was performed in the same procedure as in Example 11 except that the hard coat layer forming coating solution 7 prepared above was used instead of the hard coat layer forming coating solution 3. Film 15 was produced.

<Example 16>
(Preparation of hard coat layer forming coating solution 8)
A coating liquid 8 for forming a hard coat layer having the following composition was prepared:
Aronix M-305 (manufactured by Toagosei Co., Ltd.) 874.77 parts by mass Beam set 577 (manufactured by Arakawa Chemical Industries, Ltd.) 1104.30 parts by mass Irgacure 184 (manufactured by BASF Japan Ltd.) 60 parts by mass Irgacure 819 (BASF Japan shares) 60 parts by mass Megafac F-552 (manufactured by DIC Corporation) 0.9 parts by mass MIBK dispersion of ATO (solid content 35%; manufactured by Advanced Nano Products) 2571.43 parts by mass.

  In Example 11, optical reflection was performed in the same procedure as in Example 11 except that the hard coat layer forming coating solution 8 prepared above was used instead of the hard coat layer forming coating solution 3. Film 16 was produced.

<Example 17>
(Preparation of dielectric multilayer film)
A dielectric multilayer film having 89 layers was produced by a coextrusion method on a continuous flat film production line. The dielectric multilayer film was prepared from coPEN and PETG (available from Eastman Chemicals). The coPEN was polymerized using 90 wt% PEN and 10 wt% PET starting monomer. Using the feedblock method, an 88-layer dielectric multilayer with a nearly linear layer thickness gradient from layer to layer was made through the extrudate.

  CoPEN was supplied to the feed block by an extruder at a flow rate of about 17 kg / hour and PETG at a flow rate of about 22 kg / hour. A portion of PETG was used as a protective boundary layer on each side of the extrudate, for a total flow rate of 39 kg / hour. The material flow was then passed through an asymmetric doubler multiplier with a multiplication design ratio of 1.25. After multiplication, a skin layer (PET; manufactured by Eastman Chemicals) as a substrate was added at about 20 kg / hour supplied from the third extruder.

  The other conditions were the same as in the production of the dielectric multilayer film in Example 16. The produced film had a final thickness of about 25 μm, and the thickness of the dielectric multilayer film was 2.0 μm.

(Preparation of optical reflection film 17)
An optical reflective film 17 was produced in the same procedure as in Example 16 except that the dielectric multilayer film prepared above was used instead of the dielectric multilayer film in Example 16.

<Example 18>
(Preparation of dielectric multilayer film)
Preparation of coating liquid L1 for low refractive index layer 30 parts by mass of 3% by mass boric acid aqueous solution was stirred into 100 parts by mass of 10% by mass colloidal silica aqueous solution (Snowtex OXS, manufactured by Nissan Chemical Industries, Ltd.) heated to 40 ° C. While adding. Subsequently, 450 mass parts of 5 mass% polyvinyl alcohol (PVA235, saponification degree: 87.0 mol%, Kuraray Co., Ltd.) aqueous solution and 375 mass parts of pure water were added, stirring. Then, 1 mass part of surfactant 5 mass% aqueous solution (Softazolin LSB-R, Kawaken Fine Chemical Co., Ltd.) 1 mass part was added, stirring, and the coating liquid L1 for low refractive index layers was prepared.

Preparation of coating liquid H1 for high refractive index layer 15.0 mass% titanium oxide sol (SRD-W, volume average particle diameter: 5 nm, rutile titanium dioxide particles, manufactured by Sakai Chemical Industry Co., Ltd.) 10 mass parts pure water 40 mass After adding parts, it was heated to 90 ° C. Subsequently, 26 parts by mass of an aqueous silicic acid solution (sodium silicate 4 (manufactured by Nippon Kagaku Kogyo Co., Ltd.) diluted with pure water so that the SiO ₂ concentration becomes 4% by mass) was gradually added, and then in the autoclave. The titanium dioxide sol (hereinafter referred to as “silica”) was subjected to a heat treatment at 175 ° C. for 18 hours, and after cooling, was concentrated with an ultrafiltration membrane to deposit SiO ₂ with a solid content concentration of 20% by mass on the surface. Also referred to as “modified titanium oxide sol”.

  50 parts by mass of the 20% by mass silica-modified titanium oxide sol dispersion obtained above was heated to 40 ° C., and 10 parts by mass of a 2% by mass citric acid aqueous solution was added with stirring. Thereafter, 90 parts by mass of a 4% by mass polyvinyl alcohol (PVA124, degree of saponification: 98.5 mol%, manufactured by Kuraray Co., Ltd.) aqueous solution and 40 parts by mass of pure water were added with stirring. Finally, 1 part by mass of a 5% by mass surfactant aqueous solution (SOFTAZOLINE LSB-R, manufactured by Kawaken Fine Chemical Co., Ltd.) was added with stirring to prepare a coating solution H1 for a high refractive index layer.

(Dielectric multilayer film formation method)
Using a slide hopper coating apparatus capable of 16-layer coating, the low-refractive-index layer coating liquid L1 and the high-refractive-index layer coating liquid H1 prepared above are heated to 40 ° C., and the thickness of the substrate is 50 μm. 16 layers of simultaneous multilayer coating was performed on a polyethylene terephthalate film (A4300, with double-sided easy-adhesion layer, manufactured by Toyobo Co., Ltd.).

At this time, the lowermost layer and the outermost layer were low refractive index layers, and the others were set to be alternately laminated. The coating amount was adjusted so that the film thickness during drying was 150 nm for each low refractive index layer and 130 nm for each high refractive index layer. In addition, the confirmation of the mixed region between layers (mixed layer) and the measurement (confirmation) of the film thickness were performed by cutting the laminated film (optical reflection film sample) and cutting the cut surface with a high refractive index material (TiO ₂ ) using an XPS surface analyzer. It was confirmed that the film thickness of each layer described above was ensured by measuring the abundance of the low refractive index material (SiO ₂ ).

  Immediately after application, 5 ° C. cold air was blown and set. After completion of the setting, warm air of 80 ° C. was blown and dried to produce a dielectric multilayer film.

(Preparation of optical reflection film 18)
An optical reflective film 18 was produced in the same procedure as in Example 16 except that the dielectric multilayer film prepared above was used instead of the dielectric multilayer film in Example 16.

<Example 19>
(Preparation of coating liquid 9 for forming a hard coat layer)
A coating liquid 9 for forming a hard coat layer having the following composition was prepared:
Aronix M-305 (manufactured by Toagosei Co., Ltd.) 874.77 parts by mass Beam set 577 (manufactured by Arakawa Chemical Industries, Ltd.) 1104.30 parts by mass Irgacure 184 (manufactured by BASF Japan Ltd.) 60 parts by mass Irgacure 819 (BASF Japan shares) 60 parts by mass Megafac F-552 (manufactured by DIC Corporation) 0.9 parts by mass ITO MIBK dispersion (solid content 25%; manufactured by Advanced Nano Products) 3600.00 parts by mass.

  In Example 18, optical reflection was performed in the same procedure as in Example 18 except that the hard coat layer forming coating solution 9 prepared above was used instead of the hard coat layer forming coating solution 8. Film 19 was produced.

<Comparative Example 1>
An optical reflective film 20 was produced in the same manner as in Example 6 except that the coating thickness of the hard coat layer forming coating solution 1 was changed so that the dry thickness of the hard coat layer was 8 μm. did.

<Comparative example 2>
The optical reflective film 21 is the same as Example 10 except that the coating thickness of the hard coat layer forming coating solution 1 is changed so that the dry thickness of the hard coat layer is 0.5 μm. Was made.

<Comparative Example 3>
In the production of the dielectric multilayer film of Example 3, a dielectric multilayer film having a final thickness of 1.0 μm was produced by setting the number of layers to be coextruded by the feed block method to 45 layers, and hard An optical reflective film 22 was produced in the same manner as in Example 3 except that the coating thickness of the coating layer forming coating solution 2 was changed so that the dry thickness of the hard coat layer was 4 μm. .

<Comparative Example 4>
(Preparation of hard coat layer forming coating solution 10)
A coating liquid 10 for forming a hard coat layer having the following composition was prepared:
Aronix M-350 (manufactured by Toagosei Co., Ltd.) 1200 parts by mass UA-306T (Kyoeisha Chemical Co., Ltd.) 1439.1 parts by mass Irgacure 184 (manufactured by BASF Japan Ltd.) 60 parts by mass Irgacure 819 (manufactured by BASF Japan Ltd.) 60 Part by mass Megafac F-552 (manufactured by DIC Corporation) 0.9 part by mass.

  In Comparative Example 3, optical reflection was performed in the same procedure as Comparative Example 3 except that the hard coat layer forming coating solution 10 prepared above was used instead of the hard coat layer forming coating solution 2. Film 23 was produced.

<Comparative Example 5>
(Preparation of hard coat layer forming coating solution 11)
A coating liquid 11 for forming a hard coat layer having the following composition was prepared:
Aronix M-350 (manufactured by Toagosei Co., Ltd.) 490.23 parts by mass UA-306T (Kyoeisha Chemical Co., Ltd.) 1104.30 parts by mass Irgacure 184 (manufactured by BASF Japan Ltd.) 60 parts by mass Irgacure 819 (manufactured by BASF Japan Ltd.) ) 60 parts by mass Megafac F-552 (manufactured by DIC Corporation) 0.9 parts by mass ATO MIBK dispersion (solid content 35%; manufactured by Advanced Nano Products) 5057.14 parts by mass.

  In Comparative Example 3, optical reflection was performed in the same procedure as in Comparative Example 3 except that the hard coat layer forming coating solution 11 prepared above was used instead of the hard coat layer forming coating solution 2. Film 24 was produced.

<Comparative Example 6>
In the production of the dielectric multilayer film of Comparative Example 5, except that the number of layers to be co-extruded by the feed block method was 59 layers, so that the dielectric multilayer film having a final thickness of 1.3 μm was produced. In the same manner as in Comparative Example 5, an optical reflection film 22 was produced.

≪Evaluation of optical reflective film≫
The following evaluation was performed about the produced optical reflection film. The results are shown in Tables 1 to 3 below.

(Measurement of curl)
A sample cut to a size of 50 mm in the width direction and 3 mm in the longitudinal direction when the film was manufactured and a sample cut to a size of 3 mm in the width direction and 50 mm in the longitudinal direction were prepared. In order to reduce the contact surface of the sample as much as possible, the sample was sandwiched between jigs that can sandwich only the vicinity of the center of the sample.

  The sample was allowed to stand for one hour in the temperature and humidity environment to be measured, and the curl curvature was measured using a curl curvature measurement scale. The curl value measured at 23 ° C. and 50% RH is a (1 / m), the curl value measured at 23 ° C. and 20% RH is b (1 / m), and the curl value measured at 23 ° C. and 80% RH is c (1). / M).

  Table 2 below shows the curl measurement results of the optical reflective films prepared in each Example and Comparative Example. Here, the curl measurement result of the sample cut to a size of 50 mm in the width direction and 3 mm in the longitudinal direction at the time of manufacturing the film is expressed as a curl in the width direction. The curl measurement result of the sample cut to a size of 3 mm in the width direction and 50 mm in the longitudinal direction is expressed as a curl in the longitudinal direction. In Table 2, the curl value of the curl with the inner surface on the hard coat layer side is a positive value, and the curl value of the curl with the inner surface on the dielectric multilayer film side is expressed as a negative value.

(Weather resistance test)
Four tanks and a xenon weather meter (Xenon weather meter NX75 manufactured by Suga Test Instruments Co., Ltd.) were prepared and a cycle test was conducted by moving samples between them.

Specific cycle conditions are as follows: Condition A: Temperature −10 ° C./No humidity control, Condition B: Temperature 50 ° C./Humidity 90% RH, Condition C: Temperature 23 ° C./Humidity 10% RH, Condition D: Temperature 23 ° C. / Humidity 80% RH, condition E: 100 W xenon weather meter test (exposure to 100 W / m ² intensity xenon light using a xenon weather meter at 50 ° C. and 50% RH) A: 15 minutes → Condition B: 15 minutes → Condition C: 15 minutes → Condition D: 15 minutes) × 10 → Condition E: 11 hours → Evaluation: 1 hour.

  The above cycle test was performed, and the number of cycles until a crack was generated and the number of cycles until the adhesiveness was lowered were measured by the following methods. The number of cycles of condition A → condition B → condition C → condition D was defined as the number of cycles in this specification.

Cracks The sample was visually observed after the weather resistance test, and the number of crack generation cycles was defined as the number of cracks per 10 cm ² was 10 or more.

Adhesion According to the cross-cut method of JIS-K5600-5-6: 1999, a single-blade razor blade is placed on the outermost surface (hard coat layer side) of the obtained optical reflective film sample with respect to the surface. Cross cuts were made at intervals of 2 mm at an angle of 90 ° to produce 10 mm square grids. Cellophane tape No. manufactured by Nitto Denko Corporation 29 was affixed, the tape was peeled off, and the peeled state of the film was examined.

  When the number of cross-cut cells is n and the number of cells remaining on the support after peeling the tape is n1, F = n1 / n × 100 (%) is calculated, and the optical reflective film sample 10 The average value of the sheets was evaluated according to the following criteria.

  The point where F <70% was determined as the number of cycles for lowering adhesion.

  In actual use, when F is 70% or more, it can be said that interlayer adhesion is secured.

(Measurement of pencil hardness)
The pencil hardness is measured according to the standard of JIS K 5600-5-4: 1999. A scratch test of the outermost surface (hard coat layer side) of each sample was performed with a pencil angle of 45 ° and a load of 500 g. Ranking was performed with the hardness symbol of the pencil that was not damaged more than 4 times out of 5 times. The measurement was made using a pencil hardness meter (model number: 553-M1) manufactured by Yasuda Seiki Seisakusho.

  From the results shown in Table 3, according to the present invention, in the optical reflective film having the structure in which the dielectric multilayer film is provided on one surface of the base material and the hard coat layer is provided on the other surface, the temperature and humidity change. It can be seen that even after being exposed to a certain environment, cracks hardly occur and adhesion is maintained.

  On the other hand, as in Comparative Examples 1 to 6, when the A value or B value, which is the absolute value of the difference in curl value of the optical reflection film due to humidity change, exceeds 3, the hard coat layer is caused by changes in the temperature and humidity in the environment It has been found that cracks and peeling occur.

  Further, in comparison with Examples 1 and 2 and Examples 3 to 19, in Examples 3 to 19 where the curl direction in the width direction of the film and the curl direction in the longitudinal direction are opposite directions, The stress between the hard coat layer and the dielectric multilayer film is relieved, and the weather resistance and crack resistance are further improved.

  Further, in the optical reflective films of Examples 8 to 19 in which the film thickness of the hard coat layer is 1 to 5 μm, and in particular, the film thickness ratio of the hard coat layer / dielectric multilayer film is 0.2 to 2, further weather resistance And crack resistance improved.

  Adhesion improves when a hydroxyl group-containing polyfunctional urethane acrylate is used as the resin component constituting the hard coat layer. In particular, as in Examples 12 to 19, when the hard coat layer is formed by curing a composition containing a hydroxyl group-containing polyfunctional urethane acrylate, a photopolymerization initiator, and infrared absorbing metal oxide nanoparticles, Both the number of generation cycles and the number of adhesion degradation cycles were greatly improved, and scratch resistance was also improved.

  Further, when the dielectric multilayer film contains a water-soluble resin as in Examples 18 and 19, it is possible to produce using a water-based coating liquid, and further, coating defects such as repellency and dent are reduced, and crack resistance is improved. It is thought that it contributes to improvement.

Claims (6)

A substrate;
A dielectric multilayer film in which low-refractive index layers and high-refractive index layers are alternately stacked, disposed on one surface of the substrate;
A hard coat layer disposed on the other surface of the substrate;
An optical reflective film having
A sample obtained by cutting the optical reflecting film into a size of 50 mm in the width direction at the time of manufacture and 3 mm in the length direction, and a sample cut to a size of 3 mm in the width direction at the time of manufacture and 50 mm in the length direction. The curl value measured by placing both in an environment at a temperature of 23 ° C. and a relative humidity of 50% for 1 hour, and measuring the curl value a (1 / m) in an environment of a temperature of 23 ° C. and a relative humidity of 20% for 1 hour. When the curl value measured by placing the value in an environment of b (1 / m), temperature 23 ° C. and relative humidity 80% for 1 hour is c (1 / m), the following formulas (1) and (2) It meets,
A curl value obtained by measuring a sample obtained by cutting the optical reflective film into a size of 50 mm in the width direction and 3 mm in the longitudinal direction at the time of production in an environment of a temperature of 23 ° C. and a relative humidity of 50%, and production. Optical reflection in which the positive and negative of the curl value measured by placing a sample cut to 3 mm in the width direction and 50 mm in the longitudinal direction in an environment at a temperature of 23 ° C. and a relative humidity of 50% for 1 hour is opposite the film.
The optical reflective film according to claim 1, wherein the hard coat layer has a thickness of 1 to 5 μm. The ratio of the film thickness of the hard coat layer to the film thickness of the dielectric multilayer film (film thickness of the hard coat layer / film thickness of the dielectric multilayer film) is 0.2 to 2. 4 . Optical reflective film. The hard coat layer, a hydroxyl group-containing polyfunctional urethane acrylate, a photopolymerization initiator, and obtained by curing a composition containing an infrared absorbing metal oxide nanoparticles according to any one of claims 1 to 3 Optical reflective film. The optical reflective film according to claim 4 , wherein the content of the infrared-absorbing metal oxide nanoparticles in the hard coat layer is 20 to 50% by mass. The dielectric multilayer film, a water-soluble resin, an optical reflection film according to any one of claims 1-5.