CN107615117B - Optical reflective film - Google Patents

Abstract

The invention provides an optical reflection film having a refractive index layer containing a water-soluble resin, which is less likely to cause coating film failure and less likely to cause cracks even when used for a long period of time. An optical reflection film comprising a substrate and a dielectric multilayer film, wherein the dielectric multilayer film is disposed on one surface of the substrate and is formed by alternately laminating a low refractive index layer and a high refractive index layer, at least 1 of the low refractive index layer and the high refractive index layer is a layer containing a water-dispersible hydrophobic resin, and the layer containing the water-dispersible hydrophobic resin contains a water-soluble resin and 5 to 55 mass% of a water-dispersible hydrophobic resin with respect to the total mass.

Description

Optical reflective film

Technical Field

The present invention relates to an optical reflective film.

Background

In general, a dielectric multilayer film formed by adjusting the optical film thicknesses of a high refractive index layer and a low refractive index layer, respectively, and laminating them on a substrate surface is known to selectively reflect light of a specific wavelength. Such a dielectric multilayer film is used as an optical reflective film provided in, for example, windows of buildings or vehicle members. Such an optical reflection film transmits visible light and selectively shields near infrared rays, and can control the reflection wavelength and reflect ultraviolet rays or visible light by adjusting the film thickness or refractive index of each layer.

As a method for forming a multilayer body such as a dielectric multilayer film, a method of laminating by a dry film forming method is generally used, but the formation of a dielectric multilayer film by a dry film forming method requires much production cost, and is not practical. As a practical method, for example, a method of coating a coating liquid containing a mixture of a water-soluble resin and metal oxide particles by a wet coating method to laminate the layers is mentioned. In particular, from the viewpoint of cost, a method of producing the optical film by simultaneously applying the coating liquid for a high refractive index layer and the coating liquid for a low refractive index layer in a double layer manner is preferable.

However, it is known that a laminate formed by forming a plurality of layers by applying a coating liquid containing a water-soluble resin and laminating them is likely to cause adsorption and desorption of water. Contraction and expansion of each layer due to adsorption and desorption of moisture occur repeatedly, and cracks are generated over a period of time.

In order to improve the water resistance of a laminate containing a water-soluble resin, for example, japanese patent laid-open No. 2012-973 discloses the following method: the cross-linking agent is contained in the coating liquid, and the water-soluble resin and the cross-linking agent are cross-linked at the interface between adjacent layers, whereby adhesion between the layers is achieved and mixing of moisture is suppressed.

Disclosure of Invention

Technical problem to be solved by the invention

As described in jp 2012-973 a, the water resistance of the laminate can be improved by using a crosslinking agent in combination with a water-soluble resin. However, in the method described in japanese patent laid-open No. 2012-973, an unreacted crosslinking agent remains after the coating liquid is applied and dried, and therefore, the crosslinking agent reacts with time to cause shrinkage due to post-curing of the coating film. As a result, it was found that the generation of cracks was further deteriorated when exposed to a high-humidity environment for a long time. In order to carry out the reaction without leaving an unreacted crosslinking agent, a high temperature of about 100 ℃ is required, and this temperature is not realistic because it exceeds the glass transition temperature of the resin base material.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical reflective film having a refractive index layer containing a water-soluble resin, which is less likely to cause coating film failure and less likely to cause cracking even when used for a long period of time.

Technical solution for solving technical problem

The present inventors have conducted intensive studies to solve the above problems, and as a result, have found that: the object of the present invention is achieved by adopting the following scheme.

That is, the above-described technical problem of the present invention is solved by the following means.

1. An optical reflection film having a substrate and a dielectric multilayer film,

the dielectric multilayer film is disposed on one surface of the substrate and is formed by alternately laminating a low refractive index layer and a high refractive index layer,

at least 1 of the low refractive index layer and the high refractive index layer is a layer containing a water-dispersible hydrophobic resin, and the layer containing the water-dispersible hydrophobic resin contains a water-soluble resin and 5 to 55 mass% of the water-dispersible hydrophobic resin relative to the total mass.

2. The optical reflection film according to the above 1, wherein the layer containing a water-dispersible hydrophobic resin further contains an anionic surfactant, and the water-dispersible hydrophobic resin is an anionic emulsion resin.

3. The optical reflection film according to the above 1 or 2, wherein an uppermost layer of the dielectric multilayer film on a side opposite to a side contacting the substrate is the layer containing the water-dispersible hydrophobic resin.

4. The optical reflection film as described in any one of the above 1 to 3, wherein a lowermost layer in contact with the substrate in the dielectric multilayer film is the layer containing the water-dispersible hydrophobic resin.

5. The optical reflection film as described in any one of the above 1 to 4, wherein the uppermost layer and the lowermost layer of the dielectric multilayer film are low refractive index layers, and all the low refractive index layers are the layers containing the water-dispersible hydrophobic resin.

6. The optical reflection film according to any one of claims 1 to 5, wherein an average polymerization degree of the water-soluble resin in the water-dispersible hydrophobic resin-containing layer is 4000 to 6000.

7. The method for manufacturing an optical reflection film according to the above 2, comprising: a step of dissolving or dispersing a water-soluble resin, an anionic surfactant, and an anionic emulsion resin in an aqueous solvent to prepare a coating liquid;

a step of forming the layer containing the water-dispersible hydrophobic resin by applying the coating liquid.

Detailed Description

Hereinafter, embodiments of the present invention will be described.

One embodiment of the present invention is an optical reflective film including a substrate and a dielectric multilayer film disposed on one surface of the substrate and formed by alternately laminating a low refractive index layer and a high refractive index layer, wherein at least 1 of the low refractive index layer and the high refractive index layer is a layer containing a water-dispersible hydrophobic resin, and the layer containing the water-dispersible hydrophobic resin contains a water-soluble resin and 5 to 55 mass% of the water-dispersible hydrophobic resin with respect to the total mass.

According to the present invention, an optical reflective film having a refractive index layer containing a water-soluble resin, which is less likely to cause coating film failure and less likely to cause cracking even when used for a long period of time, can be obtained.

The optical reflection film of the present invention contains a water-soluble resin in at least 1 of the high refractive index layer and the low refractive index layer. As described above, there is a problem that cracks are generated in the optical reflective film containing the water-soluble resin over time.

Therefore, the present inventors have studied the crack (cleavage) of the optical reflective film and found that: by using a water-dispersible hydrophobic resin in a predetermined amount together with a water-soluble resin, expansion and contraction of the refractive index layer can be reduced, and generation of cracks with time can be reduced. When a water-dispersible hydrophobic resin is added to a water-soluble resin, the resin is melt-bonded to form a film, and a film having a higher hydrophobicity can be obtained as compared with a case where a water-dispersible hydrophobic resin is not added. Therefore, it is considered that the expansion and contraction of the film due to the change in the amount of moisture in the atmosphere can be reduced, and therefore, the occurrence of cracks can be prevented. In addition, the emulsion resin can soften the coating film, thereby reducing coating film failure. In particular, it is considered that by combining an anionic surfactant and an anionic water-dispersible hydrophobic resin, stability in a coating solution of the water-dispersible hydrophobic resin is improved, local aggregation and the like during drying of a coating film is suppressed, and failure of the coating film can be further reduced.

Here, the content of the water-dispersible hydrophobic resin is 5 to 55 mass% with respect to the total mass (solid content mass) of the layer containing the water-dispersible hydrophobic resin, and an excellent crack prevention effect can be obtained. In addition, coating film failure can be reduced. When the content of the water-dispersible hydrophobic resin is less than 5% by mass, the melt-sticking of the water-dispersible hydrophobic resins to each other is reduced, and the effects of the present invention cannot be sufficiently obtained. On the other hand, when the content of the water-dispersible hydrophobic resin is more than 55% by mass, voids are easily formed with the water-soluble resin, and the haze of the coating film is easily increased. When the content of the water-dispersible hydrophobic resin is more than 55% by mass, the viscosity of the coating liquid decreases in aqueous coating, particularly simultaneous double coating. Therefore, a uniform coating film is not easily formed, and cracks are easily generated with time. In addition, coating failure is also likely to occur. Further, the viscosity of the coating liquid is reduced, and the refractive index layers are mixed with each other, so that haze is easily generated. The content of the water-dispersible hydrophobic resin is preferably 10 to 40% by mass, more preferably 10 to 30% by mass, based on the total mass of the layer containing the water-dispersible hydrophobic resin. When 2 or more kinds of water-dispersible hydrophobic resins are used, the total amount thereof is adjusted to the above range. When the laminate has 2 or more layers containing a water-dispersible hydrophobic resin, the content of the water-dispersible hydrophobic resin in at least 1 layer may be in the above range, but more preferably, the content of all layers is in the above range.

Hereinafter, the constituent elements of the optical reflection film of the present invention will be described in detail. In the following, when the low refractive index layer and the high refractive index layer are not distinguished from each other, the layers are referred to as "refractive index layers" as a concept including both layers.

In the present specification, "X to Y" indicating a range means "X to Y. Unless otherwise specified, the operation and the measurement of physical properties are carried out at room temperature (20 to 25 ℃) and at a relative humidity of 40 to 50%.

[ optical reflection film ]

The optical reflection film of the present invention has a substrate and a dielectric multilayer film in which a low refractive index layer and a high refractive index layer are alternately laminated, and the dielectric multilayer film is disposed on one surface of the substrate.

[ base Material ]

The optical reflection film of the present invention includes a substrate for supporting a dielectric multilayer film or the like. As the substrate, various resin films can be used, and polyolefin films (polyethylene, polypropylene, and the like), polyester films (polyethylene terephthalate (PET), polyethylene naphthalate, and the like), polyvinyl chloride, cellulose triacetate, and the like can be used, and a polyester film is preferable. The polyester film (hereinafter referred to as polyester) is not particularly limited, and is preferably a polyester having film formability which contains a dicarboxylic acid component and a diol component as main components.

Examples of the dicarboxylic acid component as a main constituent component include: terephthalic acid, isophthalic acid, phthalic acid, 2, 6-naphthalenedicarboxylic acid, 2, 7-naphthalenedicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenyletherdicarboxylic acid, diphenylethanedicarboxylic acid, cyclohexanedicarboxylic acid, diphenyldicarboxylic acid, diphenylthioether dicarboxylic acid, diphenylketodicarboxylic acid, phenylindanedicarboxylic acid, and the like. Further, examples of the diol component include: ethylene glycol, propylene glycol, butylene glycol, cyclohexanedimethanol, 2-bis (4-hydroxyphenyl) propane, 2-bis (4-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, bisphenol fluorene dihydroxyethyl ether, diethylene glycol, neopentyl glycol, hydroquinone, cyclohexanediol, and the like. Among the polyesters having these as main components, polyesters having ethylene glycol or 1, 4-cyclohexanedimethanol as a main component are preferable as the dicarboxylic acid component, terephthalic acid, 2, 6-naphthalenedicarboxylic acid, and a diol component, from the viewpoints of transparency, mechanical strength, dimensional stability, and the like. Among these, preferred are polyesters containing polyethylene terephthalate or polyethylene naphthalate as a main component, copolyesters composed of terephthalic acid, 2, 6-naphthalenedicarboxylic acid and ethylene glycol, and polyesters containing a mixture of 2 or more of these polyesters as a main component.

The thickness of the substrate used in the present invention is preferably 10 to 300. mu.m, and particularly preferably 20 to 150. mu.m. The base material may be a base material in which 2 sheets are stacked, and in this case, the types thereof may be the same or different.

The transmittance in the visible light region of the base material as defined in JIS R3106-1998 is preferably 85% or more, particularly preferably 90% or more. When the base material has the above transmittance or more, it is preferable to set the transmittance in the visible light region shown in JIS R3106-1998 to 50% or more (upper limit: 100%) when a laminated film is produced.

The substrate using the resin or the like may be an unstretched film or a stretched film. The stretched film is preferable in terms of improving strength and suppressing thermal expansion.

The substrate can be produced by a conventionally known general method. For example, an unstretched substrate that is substantially amorphous and not oriented can be produced by melting a resin as a material with an extruder, extruding the melted resin with an annular die or a T-die, and quenching the extruded resin. Further, a stretched substrate can be produced by stretching an unstretched substrate in the direction of the flow of the substrate (vertical axis) or in the direction perpendicular to the flow of the substrate (horizontal axis) by a known method such as uniaxial stretching, tenter sequential biaxial stretching, tenter simultaneous biaxial stretching, or tubular simultaneous biaxial stretching. The stretch ratio in this case may be appropriately selected in accordance with the resin as the base material, but is preferably 2 to 10 times in the vertical axis direction and the horizontal axis direction, respectively.

[ dielectric multilayer film ]

The dielectric multilayer film has a structure in which low refractive index layers and high refractive index layers are alternately stacked, and has at least 1 unit formed of the low refractive index layer and the high refractive index layer. Since the dielectric multilayer film has such a structure including such refractive index layers having different refractive indices, when light having a predetermined wavelength (for example, infrared light) is incident, at least a part of the light is reflected to exhibit a shielding effect (and a heat insulating effect in the case of infrared light).

In this embodiment, the refractive index layer constituting the dielectric multilayer film is a low refractive index layer or a high refractive index layer, and is judged by comparing the refractive index with that of the adjacent refractive index layer. Specifically, when a certain refractive index layer is used as the reference layer, if the refractive index layer adjacent to the reference layer has a lower refractive index than the reference layer, it is determined that the reference layer is a high refractive index layer (the adjacent layer is a low refractive index layer). On the other hand, if the refractive index of the adjacent layer is higher than that of the reference layer, the reference layer is determined to be a low refractive index layer (the adjacent layer is a high refractive index layer). Therefore, the refractive index layer is a high refractive index layer or a low refractive index layer, and is relatively high or low depending on the relationship with the refractive index of the adjacent layer, and a certain refractive index layer may be a high refractive index layer or a low refractive index layer depending on the relationship with the adjacent layer.

The refractive index layer is not particularly limited as long as at least 1 of the high refractive index layer and the low refractive index layer constituting the dielectric multilayer film contains a water-dispersible hydrophobic resin, and the water-dispersible hydrophobic resin-containing layer contains a water-soluble resin and a water-dispersible hydrophobic resin in an amount of 5 to 55 mass% based on the total mass of the refractive index layers, and known refractive index layers used in the art can be used. As the known refractive index layer, for example, a refractive index layer formed by a wet film forming method is preferably used from the viewpoint of production efficiency.

In addition, from the viewpoint of reflection characteristics, at least one of the high refractive index layer and the low refractive index layer preferably contains metal oxide particles, and more preferably, both of the high refractive index layer and the low refractive index layer contain metal oxide particles.

In addition, as described above, in the dielectric multilayer film of the optical reflection film of the present invention, a water-soluble resin is used for at least 1 of the high refractive index layer and the low refractive index layer. The refractive index layer of the optical reflective film formed by the wet film forming method is preferably a coating film formed by applying a coating liquid (usually containing an aqueous solvent such as water) containing a water-soluble resin. The water-soluble resin is preferably used because it does not use an organic solvent, and therefore, it is less environmentally responsible, and because it has high flexibility, it improves the durability of the film when bent. The water-soluble resin is preferably used particularly when metal oxide particles are contained in at least 1 of the high refractive index layer and the low refractive index layer.

In this specification, "water-soluble" means: when the insoluble matter is dissolved in water at a temperature at which the matter is most soluble and the concentration of the insoluble matter is 0.5 mass%, the mass of the insoluble matter separated by filtration is 50 mass% or less of the added polymer when the insoluble matter is filtered through a G2 glass filter (maximum pore size 40 to 50 μm).

As described above, the low refractive index layer or the high refractive index layer is a layer having a relatively high or low refractive index determined by the relationship with the adjacent refractive index layer, and the refractive index layer may be a low refractive index layer or a high refractive index layer.

(high refractive index layer)

The high refractive index layer preferably contains a water-soluble resin. Further, the metal oxide particles, a curing agent, a surfactant, and other additives may be contained as necessary. The water-soluble resin and the metal oxide particles contained in the high refractive index layer are hereinafter referred to as "1 st water-soluble resin" and "1 st metal oxide particles", respectively, for convenience.

In this case, the refractive index of the 1 st metal oxide particles is preferably higher than the refractive index of the 2 nd metal oxide particles contained in the low refractive index layer described later. It is preferable that the high refractive index layer and/or the low refractive index layer contain metal oxide particles because the difference in refractive index between the refractive index layers can be increased, and the transparency of the film can be improved by reducing the number of stacked layers. In addition, there are the following advantages: the film has stress relaxation effect, and the film properties (bending properties at bending and high temperature and high humidity) are improved. The metal oxide particles may be contained in any refractive index layer, but it is preferable that at least the high refractive index layer contains the metal oxide particles, and it is more preferable that both the high refractive index layer and the low refractive index layer contain the metal oxide particles.

(1) 1 st Water-soluble resin

The 1 st water-soluble resin is not particularly limited, and a polyvinyl alcohol resin, gelatin, cellulose, a mucopolysaccharide, and a polymer having a reactive functional group can be used. Among them, polyvinyl alcohol resins are preferably used.

Polyvinyl alcohol resin

Examples of the polyvinyl alcohol resin include modified polyvinyl alcohols such as ordinary polyvinyl alcohol (unmodified polyvinyl alcohol) obtained by hydrolyzing polyvinyl acetate, cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, and vinyl alcohol polymers. The adhesion to a film, water resistance, and flexibility of the modified polyvinyl alcohol may be improved.

Gelatin

As the gelatin, various kinds of gelatin which have been widely used in the field of silver halide photographic photosensitive materials can be applied. Examples thereof include: acid-treating gelatin; alkali-treating gelatin; enzyme-treated gelatin in which an enzyme treatment is performed in the production process of gelatin; gelatin derivatives having an amino group, an imino group, a hydroxyl group, and a carboxyl group as functional groups in the molecule, and modified by treatment with a reagent having a group reactive therewith.

When gelatin is used, a hard coat agent of gelatin may be added as needed.

Cellulose type

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

Viscosity increasing polysaccharide

The mucopolysaccharide is a polymer of saccharides and has a plurality of hydrogen bonding groups in the molecule. The mucopolysaccharide has a characteristic that the difference between the intermolecular hydrogen bonding force due to temperature is large between the viscosity at low temperature and the viscosity at high temperature. In addition, when metal oxide particles are added to the thickening polysaccharide, an increase in viscosity is caused, which is considered to be caused by hydrogen bonding with the metal oxide particles at low temperatures. The viscosity at 15 ℃ is usually 1.0 mPas or more, preferably 5.0 mPas or more, more preferably 10.0 mPas or more in terms of the extent of increase in viscosity.

The thickening polysaccharide to be used is not particularly limited, and may be a natural pure polysaccharide, a natural complex polysaccharide, a synthetic pure polysaccharide, or a synthetic complex polysaccharide, which are generally known. For details of these polysaccharides, reference is made to "Biochemical dictionary (2 nd edition), published by Tokyo Chemicals, volume 31 (1988), page 21 of the" food industry ", and the like.

Polymers having reactive functional groups

examples of the polymer having a reactive functional group include acrylic resins such as polyvinyl pyrrolidone, polyacrylic acid, acrylic acid-acrylonitrile copolymer, potassium acrylate-acrylonitrile copolymer, vinyl acetate-acrylic ester copolymer, and acrylic acid-acrylic ester copolymer, styrene acrylic resins such as styrene-acrylic acid copolymer, styrene-methacrylic acid-acrylic ester copolymer, styrene- α -methylstyrene-acrylic acid copolymer, and styrene- α -methylstyrene-acrylic acid-acrylic ester copolymer, styrene-sodium styrene sulfonate 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, vinyl acetate-crotonic acid copolymer, and vinyl acetate-acrylic acid copolymer, and salts thereof.

The water-soluble resins may be used alone or in combination of 2 or more.

The weight average molecular weight of the 1 st water-soluble resin is preferably 1000 to 200000, and more preferably 3000 to 40000. In the present specification, the value of the "weight average molecular weight" is a value measured by Gel Permeation Chromatography (GPC).

The content of the 1 st water-soluble resin is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, based on 100% by mass of the solid content of the high refractive index layer.

(2) 1 st Metal oxide particle

The 1 st metal oxide particle is not particularly limited, and a metal oxide particle having a refractive index of 2.0 to 3.0 is preferable. Specifically, there may be mentioned: titanium oxide, zirconium oxide, zinc oxide, aluminum oxide, colloidal aluminum oxide, lead titanate, red lead, chrome yellow, zinc chromate, chromium oxide, iron black, copper oxide, magnesium hydroxide, strontium titanate, yttrium oxide, niobium oxide, europium oxide, lanthanum oxide, zircon, tin oxide, and the like. Among them, the 1 st metal oxide particles are preferably titanium oxide or zirconium oxide from the viewpoint of forming a transparent high refractive index layer having a high refractive index, and more preferably rutile-type (tetragonal form) titanium oxide from the viewpoint of improving weather resistance.

The titanium oxide may be in the form of core-shell particles coated with a hydrated oxide containing silicon. The core-shell particle has the following structure: the surface of the titanium oxide particle as the core is coated with a shell comprising hydrated oxide containing silicon. In this case, the volume average particle diameter of the titanium oxide particles as the core portion is preferably more than 1nm and less than 30nm, and more preferably less than 4nm and not less than 30 nm. By containing such core-shell particles, interlayer mixing of the high refractive index layer and the low refractive index layer can be suppressed by the interaction of the silicon-containing hydrated oxide of the shell layer and the water-soluble resin.

The 1 st metal oxide particles may be used alone or in combination of 2 or more.

The content of the 1 st metal oxide particles is preferably 15 to 80% by mass, more preferably 20 to 77% by mass, and still more preferably 30 to 75% by mass, based on 100% by mass of the solid content of the high refractive index layer, from the viewpoint of increasing the difference in refractive index from the low refractive index layer.

The volume average particle diameter of the 1 st metal oxide particles is preferably 30nm or less, more preferably 1 to 30nm, and still more preferably 5 to 15 nm. When the volume average particle diameter is 30nm or less, haze is small and visible light transmittance is excellent, and therefore, the volume average particle diameter is preferable. In the present specification, the value of the "volume average particle diameter" is a value measured by the following method. Specifically, the particle size was measured by observing 1000 arbitrary particles appearing on the cross section or the surface of the refractive index layer with an electron microscope, and in the case where n1 and n2 … … ni … … nk metal oxide particles were present in each of the particles having the particle sizes of d1 and d2 … … di … … dk, the volume average particle size (mv) was calculated by the following formula assuming that the volume of each 1 particle was vi.

[ mathematical formula 1]

mv＝{∑(vi·di)/(∑(vi))}

(3) Curing agent

The curing agent has a function of reacting with the 1 st water-soluble resin (preferably, polyvinyl alcohol-based resin) contained in the high refractive index layer and forming a network of hydrogen bonds.

The curing agent is not particularly limited as long as it causes a curing reaction with the 1 st water-soluble resin, and generally, a compound having a group capable of reacting with the water-soluble resin or a compound promoting a reaction between different groups of the water-soluble resin may be mentioned.

Specifically, when a polyvinyl alcohol resin is used as the 1 st water-soluble resin, boric acid and a salt thereof are preferably used as the curing agent. Further, a known curing agent other than boric acid and its salt may be used.

Boric acid and salts thereof mean an oxyacid having a boron atom as a central atom and salts thereof. Specifically, orthoboric acid, diboric acid, metaboric acid, tetraboric acid, pentaboric acid, octaboric acid, and salts thereof may be mentioned.

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

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

Surface active agent

The surfactant is not particularly limited, and examples thereof include: a zwitterionic surfactant, a cationic surfactant, an anionic surfactant, a fluorine-based surfactant, and a silicon-based surfactant. Among them, acrylic surfactants, silicon surfactants, or fluorine surfactants can be used. The surfactant is preferably a surfactant containing a long-chain alkyl group, and more preferably a surfactant having an alkyl group having 6 to 20 carbon atoms.

Examples of the zwitterionic surfactant include: alkyl betaines, alkylamine oxides, cocamidopropyl betaine, lauramidopropyl betaine, palm kernel oil fatty acid amidopropyl betaine, cocoamphoacetic acid Na, lauroamphoacetic acid Na, lauramidopropyl hydroxybetaine, lauramidopropyl amine oxide, myristamidopropyl amine oxide, hydroxyalkyl (C12-14) hydroxyethyl sarcosine.

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

The anionic surfactant is a surfactant in which a hydrophilic group is ionized into an anion in an aqueous solution, and examples of the anionic surfactant include: sulfuric acid ester salts, sulfonic acid salts, carboxylic acid salts, phosphoric acid ester salts, and the like. For example, alkyl sulfate ester salts, polyoxyethylene alkyl ether sulfate ester salts, polyoxyethylene aryl ether sulfate ester salts, alkylbenzenesulfonate salts, fatty acid salts, polyoxyethylene alkyl ether phosphate salts, and dipotassium alkenylsuccinate salts can be used. Examples of commercially available anionic surfactants include sulfate ester salts: EMAL (registered trademark) manufactured by Kao corporation, HITENOL (registered trademark) NF-08, HITENOL NF-0825, HITENOL NF-13, HITENOL NF-17 (both polyoxyethylene styrenated phenyl ether ammonium sulfate) manufactured by first Industrial Co., Ltd, and the like, and examples of the sulfonate include NEOPELEX (registered trademark) and PELEX (registered trademark) manufactured by Kao corporation. Examples of the carboxylate include NEO-HITENOL (registered trademark) manufactured by first Industrial pharmaceutical Co., Ltd, and examples of the phosphate ester salt include PLYSURF (registered trademark) manufactured by first Industrial pharmaceutical Co., Ltd. In the present invention, from the viewpoint of miscibility with a liquid, a sulfate ester salt or a sulfonate salt is preferable.

Examples of the nonionic surfactant include: polyoxyethylene alkyl ethers (e.g., Emulgen (registered trademark) manufactured by kao corporation), polyoxyethylene sorbitan fatty acid esters (e.g., rheedol (registered trademark) TW series manufactured by kao corporation), glycerin fatty acid esters, polyoxyethylene alkylamines, and alkylalkanolamides. Alternatively, as the polyoxyethylene alkyl ether, polyoxyethylene mono 2-ethylhexyl ether or polyoxyethylene decyl ether (for example, Noigen (registered trademark) XL-40, NoigenXL-50, NoigenXL-60, etc., manufactured by first Industrial pharmaceutical Co., Ltd.) can be used.

Examples of the fluorine-based surfactant include: SURLON S-211, SURLON S-221, SURLON S-231, SURLON S-241, SURLON S-242, SURLON S-243, S-420(AGC SEIMI CHEMICAL Co., Ltd.), MEGAFACE F-114, MEGAFACE F-410, MEGAFACE F-477, MEGAFACE F-553(DIC Co., Ltd.), MEGAFACE FC-430, MEGAFACE FC-4430, MEGAFACE FC-4432(3M Co., Ltd.).

Examples of the silicon-based surfactant include: BYK-345, BYK-347, BYK-348 and BYK-349(BYK-Chemie Japan K.K.).

The high refractive index layer may contain other additives. Examples of the other additives include amino acids and lithium compounds. Further, the ultraviolet absorbers described in Japanese patent application laid-open Nos. 57-74193, 57-87988, and 62-261476; fading preventing agents described in, for example, Japanese patent laid-open Nos. 57-74192, 57-87989, 60-72785, 61-146591, 1-95091, and 3-13376; fluorescent whitening agents described in Japanese patent laid-open Nos. 59-42993, 59-52689, 62-280069, 61-242871, and 4-219266; pH regulators such as sulfuric acid, phosphoric acid, acetic acid, citric acid, sodium hydroxide, potassium carbonate, etc.; defoaming agents; lubricants such as diethylene glycol; a preservative; a mold inhibitor; an antistatic agent; a matting agent; a heat stabilizer; an antioxidant; a flame retardant; a crystal nucleating agent; inorganic particles; organic particles; viscosity reducing agent; a lubricant; an infrared absorber; a pigment; various known additives such as pigments are used as the other additives.

(Low refractive index layer)

In addition, the low refractive index layer preferably contains a water-soluble resin. Further, the metal oxide particles, a curing agent, a surfactant, and other additives may be contained as required. The water-soluble resin and the metal oxide particles contained in the low refractive index layer are hereinafter referred to as "2 nd water-soluble resin" and "2 nd metal oxide particles", respectively, for convenience.

(1) 2 nd Water-soluble resin

The same substance as that of the 1 st water-soluble resin can be used as the 2 nd water-soluble resin.

In this case, when the polyvinyl alcohol-based resin is used as both the 1 st water-soluble resin and the 2 nd water-soluble resin, the polyvinyl alcohol-based resins having different degrees of saponification are preferably used for the high refractive index layer and the low refractive index layer. This suppresses mixing at the interface, and the reflectance (for example, infrared reflectance (infrared shielding rate)) becomes better, and the haze can be reduced. In the present specification, "saponification degree" means a ratio of total hydroxyl groups with respect to propionyloxy groups (substances derived from vinyl acetate as a raw material) and hydroxyl groups in the polyvinyl alcohol-based resin.

The content of the 2 nd water-soluble resin is preferably 3 to 60 mass%, more preferably 10 to 45 mass% with respect to 100 mass% of the solid content in the low refractive index layer.

(2) 2 nd metal oxide particles

The metal oxide particles of the 2 nd metal oxide are not particularly limited, but silica (silica) such as synthetic amorphous silica or colloidal silica is preferably used, and an acidic colloidal silica sol is more preferably used. From the viewpoint of further lowering the refractive index, hollow fine particles having pores in the particles can be used as the 2 nd metal oxide particles, and hollow fine particles of silica (silica) are particularly preferably used.

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

The 2 nd metal oxide particles may be surface-coated with a surface coating component.

The average particle diameter (number average; diameter) of the 2 nd metal oxide particles (preferably silica) contained in the low refractive index layer of the present invention is preferably 3 to 100nm, more preferably 3 to 50 nm. In the present specification, the "average particle diameter (number average; diameter)" of the metal oxide particles is determined as a simple average value (number average) of the particle diameters of 1,000 arbitrary particles measured by observing the particles themselves or the particles appearing on the cross section or the surface of the refractive index layer with an electron microscope. Here, the particle diameters of the respective particles are expressed by diameters assuming circles equal to the projected areas thereof.

The content of the 2 nd metal oxide particles in the low refractive index layer is preferably 0.1 to 70 mass%, more preferably 30 to 70 mass%, and still more preferably 45 to 65 mass% with respect to 100 mass% of the total solid content of the low refractive index layer.

The above-mentioned 2 nd metal oxide may be used alone or in combination of 2 or more from the viewpoint of adjusting the refractive index.

Curing agents, surfactants, other additives

Since the same curing agent, surfactant, and other additives as those used for the high refractive index layer can be used, the description thereof will be omitted.

(layer containing Water-dispersible hydrophobic resin)

As described above, the optical reflection film of the present invention is characterized in that at least 1 of the high refractive index layer and the low refractive index layer constituting the dielectric multilayer film is a layer containing a water-dispersible hydrophobic resin containing a water-soluble resin and a water-dispersible hydrophobic resin, and the water-dispersible hydrophobic resin is contained in an amount of 5 to 55 mass% (mass of solid content) based on the total mass (mass of solid content) of the layer containing the water-dispersible hydrophobic resin.

The layer containing a water-dispersible hydrophobic resin may be a high refractive index layer or a low refractive index layer as long as it contains a water-soluble resin and a prescribed amount of a water-dispersible hydrophobic resin. The layer containing a water-dispersible hydrophobic resin may be the same as the high refractive index layer and the low refractive index layer described above, except that the layer contains a water-dispersible hydrophobic resin described below in a predetermined amount. In general, the water-dispersible hydrophobic resin is a low refractive index (about 1.5), and therefore, when the water-dispersible hydrophobic resin remains unsoldered, the haze may be increased by the refractive index of the high refractive index layer, and therefore, the layer containing the water-dispersible hydrophobic resin is preferably a low refractive index layer.

In addition, the optical reflection film of the present invention may be such that at least 1 of the high refractive index layer and the low refractive index layer constituting the dielectric multilayer film is a layer containing a water-dispersible hydrophobic resin, and preferably, the lowermost layer in contact with the substrate or the uppermost layer on the opposite side of the substrate is a layer containing a water-dispersible hydrophobic resin. More preferably, the low refractive index layer containing all of the lowermost layer and the uppermost layer is a layer containing a water-dispersible hydrophobic resin.

Water-dispersible hydrophobic resin

The water-dispersible hydrophobic resin suitable for use in the present invention is a resin formed by welding a hydrophobic polymer dispersed in an aqueous solvent at the time of film formation of a refractive index layer in the production process of an optical reflective film.

The water-dispersible hydrophobic resin may be an emulsion resin. The emulsion resin is obtained by emulsion-polymerizing an oil-soluble monomer using a dispersant such as a polymer dispersant, in which fine resin particles having an average particle diameter of, for example, 2.0 μm or less are dispersed in an aqueous medium in the form of a resin emulsion.

The oil-soluble monomer to be used is not particularly limited, and there may be mentioned: diisocyanates such as ethylene, propylene, butadiene, vinyl acetate and partial hydrolyzates thereof, vinyl ethers, acrylic acid and esters thereof, methacrylic acid and esters thereof, acrylamide and derivatives thereof, methacrylamide and derivatives thereof, styrene, divinylbenzene, vinyl chloride, vinylidene chloride, maleic acid, vinylpyrrolidone, 1, 6-hexamethylene diisocyanate, polyisocyanates, glycols, polyols, dicarboxylic acids, and the like.

The usable dispersant is not particularly limited, and examples thereof include low molecular weight dispersants such as alkylsulfonates, alkylbenzenesulfonates, diethylamines, ethylenediamine, and quaternary ammonium salts, and in addition to these, include: and polymer dispersants such as polyoxyethylene nonylphenyl ether, polyethoxyethylenelauric ether, hydroxyethylcellulose, and polyvinylpyrrolidone.

Examples of the resin to be emulsion polymerized include: acrylic resins, styrene-butadiene resins, ethylene-vinyl acetate resins, polyurethane resins, phenol resins, acrylate resins, and the like.

As the emulsion resin, commercially available emulsion resins can be used, and examples thereof include: mowinyl 718A, Mowinyl A, Mowinyl A, Mowinyl LDM7582, Mowinyl 5450, Mowinyl 6960 (manufactured by Nippon Synthesis chemical Co., Ltd.), SUPERFLEX (registered trademark) 150, 170, 300, 500M (manufactured by first Industrial pharmaceutical Co., Ltd.), ADEKA BONTIGHTER HUX-232, HUX-380, HUX-386, HUX-830, HUX-895 (manufactured by ADEKA Co., Ltd.), AE-116, AE-120A, AE-200-A, AE-981-A, AE-986B (manufactured by E-TEC Co., Ltd.), ETNACOLLUW-1005E, UW-5002, UW-5034E, UE-5502 (manufactured by Yushixing Co., Ltd.), and UVable Silicone-Acrylic Polymer (UW-309, AcIc-319-493) 23-31W-493 (manufactured by Fine Ucurr chemical Co., Ltd.), and UVable Silicone-Acrylic Polymer (UW-31-Polymer UW-493) 734 (manufactured by Ucurr chemical Co., Ltd.) Manufactured), and the like.

Any of anionic emulsion resin, cationic emulsion resin, and anionic emulsion resin can be used as the emulsion resin, but in the layer containing a water-dispersible hydrophobic resin in the optical reflection film of the present invention, it is preferable to use an anionic emulsion resin in combination with an anionic surfactant.

It is considered that when an anionic emulsion resin is added to a coating liquid in which inorganic particles such as metal oxide particles, a water-soluble resin, and a surfactant are dispersed in an aqueous solvent, and an anionic surfactant is further used as the surfactant, the structural viscosity of the coating liquid is stabilized, the dispersion state is improved, and the increase in viscosity is suppressed. As a result, the coating failure, particularly the coating failure in the form of a thin stripe, is remarkably improved, and the yield of the product can be greatly improved.

Here, as the anionic emulsion resin, an anionic urethane emulsion resin, an anionic acrylic emulsion resin, an anionic styrene-acrylic copolymer emulsion resin, or the like can be preferably used. As the anionic surfactant, the same ones as described above can be used.

The particle size of the emulsion resin is not particularly limited, and the average particle size is preferably 1 to 100nm, more preferably 5 to 60 nm. When the emulsion resin has the above average particle diameter, the haze of the optical reflective film obtained is reduced, and the transparency can be improved. The average particle diameter of the emulsion resin can be measured by a dynamic light scattering method.

The refractive index of the emulsion resin is not particularly limited, but is preferably 1.3 to 1.7, and more preferably 1.4 to 1.6. When the refractive index is within the above range, the refractive index is close to that of the water-soluble resin, and therefore, the haze of the optical reflective film to be obtained can be reduced.

The above emulsion resin preferably has a glass transition temperature (Tg) of 20 ℃ or less, more preferably-30 to 10 ℃ from the viewpoint of improving flexibility.

Metal oxide particles

The layer containing a water-dispersible hydrophobic resin may contain metal oxide particles. The metal oxide particles can be the same as those used for the high refractive index layer and the low refractive index layer.

Water-soluble resin

The layer containing a water-dispersible hydrophobic resin in the optical reflection film of the present invention contains a water-soluble resin. As the water-soluble resin, the same materials as those of the high refractive index layer and the low refractive index layer described above can be used.

The average polymerization degree of the water-soluble resin in the water-dispersible hydrophobic resin-containing layer is preferably 1500 to 6000, and more preferably 4000 to 6000. The average degree of polymerization of the water-soluble resin in the water-dispersible hydrophobic resin-containing layer is more preferably 4000 to 5000, and still more preferably 4500 to 5000. When the average polymerization degree of the water-soluble resin is 1500 or more, the water-soluble resin can be suppressed from diffusing and generating haze even when coated by the simultaneous multilayer coating method. Further, if the average polymerization degree of the water-soluble resin is 6000 or less, the viscosity of the coating liquid is not excessively increased, and therefore, it is suitable for the production of a dielectric multilayer film by coating. In the case of having a plurality of layers containing a water-dispersible hydrophobic resin, the average degree of polymerization of the water-soluble resin in at least 1 layer containing a water-dispersible hydrophobic resin is preferably within the above range, and more preferably the average degree of polymerization of the water-soluble resin in all the layers containing a water-dispersible hydrophobic resin is within the above range.

The water-soluble resin in the layer containing a water-dispersible hydrophobic resin is preferably a polyvinyl alcohol resin. This stabilizes the dispersibility of the water-dispersible hydrophobic resin, and suppresses an increase in haze. The saponification degree of the polyvinyl alcohol resin is, for example, 70 to 99.5 mol%, preferably 80 to 95 mol%, more preferably 85 to 90 mol%, from the viewpoint of further suppressing the haze. The average degree of polymerization of the water-soluble resin is a viscosity average degree of polymerization, and the average degree of polymerization of the polyvinyl alcohol-based resin may be set to japanese industrial specification jis k 6726: 1994 as benchmark.

In a preferred embodiment of the present invention, the uppermost layer of the refractive index layers constituting the dielectric multilayer film on the side opposite to the side contacting the substrate is a layer containing a water-dispersible hydrophobic resin. More preferably, in this case, the average degree of polymerization of the water-soluble resin in the water-dispersible hydrophobic resin-containing layer is 4000 to 6000. The average degree of polymerization of the water-soluble resin in the water-dispersible hydrophobic resin-containing layer is more preferably 4000 to 5000, and still more preferably 4500 to 5000. In this case, the effect of the present invention can be more remarkably obtained as long as the layer containing the water-dispersible hydrophobic resin contains the anionic emulsion resin and the anionic surfactant.

As described above, in the optical reflective film of the present invention, at least 1 of the high refractive index layer and the low refractive index layer constituting the dielectric multilayer film may be a layer containing a water-dispersible hydrophobic resin, but when the uppermost layer of the dielectric multilayer film is bonded to a substrate such as glass via an adhesive layer and used as an optical reflector, for example, absorption and desorption of moisture in the environment occur, and when the layer expands and contracts, stress generated in association therewith tends to concentrate. Therefore, in order to improve the weather resistance of the optical reflective film, it is effective to dispose a layer containing a water-dispersible hydrophobic resin capable of suppressing adsorption and desorption of moisture in the environment on the uppermost layer.

When a dielectric multilayer film is produced by applying a coating liquid containing a water-soluble resin, if the average polymerization degree of the water-soluble resin is, for example, 1500 or more, preferably 4000 or more, even when the coating is performed by the simultaneous multilayer coating method, the diffusion of the water-soluble resin can be suppressed and the haze can be generated. Further, if the average polymerization degree of the water-soluble resin is 6000 or less, the viscosity of the coating liquid is not excessively increased, and therefore, it is suitable for the production of a dielectric multilayer film by coating. The average degree of polymerization of the water-soluble resin is more preferably 4000 to 5000, and still more preferably 4500 to 5000.

In a further preferred embodiment of the present invention, in the refractive index layers constituting the dielectric multilayer film, the lowermost layer in contact with the substrate is a layer containing a water-dispersible hydrophobic resin. When expansion and contraction of the layers occur due to adsorption and desorption of moisture in the environment, the lowermost layer of the dielectric multilayer film is a layer in which stress generated in association with the layer is more likely to concentrate than the inner layer, and therefore, it is preferable that the lowermost layer is a layer containing a water-dispersible hydrophobic resin. More preferably, the uppermost layer and the lowermost layer are both layers containing a water-dispersible hydrophobic resin. In this case, the effect of the present invention can be more remarkably obtained as long as the layer containing the water-dispersible hydrophobic resin contains the anionic emulsion resin and the anionic surfactant.

In a preferred embodiment of the present invention, the uppermost layer and the lowermost layer of the dielectric multilayer film are low refractive index layers, and all the low refractive index layers are layers containing a water-dispersible hydrophobic resin. Thus, in the dielectric multilayer film using the water-soluble resin, the adsorption and desorption of moisture caused by the fluctuation of the moisture content in the environment can be further reduced, and therefore, the occurrence of cracks when exposed to high humidity for a long period of time can be further reduced. In this case, when the average degree of polymerization of the water-soluble resin in the layer containing the water-dispersible hydrophobic resin is 4000 to 6000, even when the water-dispersible hydrophobic resin is contained in all the low refractive index layers, the haze is not easily increased.

The thickness of the layer containing the water-dispersible hydrophobic resin is not particularly limited, and when the layer containing the water-dispersible hydrophobic resin is a high refractive index layer, the thickness of each 1 layer is preferably 20 to 800nm, more preferably 50 to 500 nm. When the layer containing the water-dispersible hydrophobic resin is a low refractive index layer, the thickness of each 1 layer is preferably 20 to 800nm, more preferably 50 to 500 nm.

[ optical characteristics ]

In the case where the optical reflection film of the present invention is an infrared shielding film that reflects infrared light, it is preferable to design the difference in refractive index between the low refractive index layer and the high refractive index layer to be large in order to increase the infrared reflectance with a small number of layers. In this embodiment, in at least 1 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 is preferably 0.1 or more, more preferably 0.3 or more, further preferably 0.35 or more, and particularly preferably 0.4 or more. In the case of a laminate having a plurality of high refractive index layers and low refractive index layers, the difference in refractive index between the high refractive index layers and the low refractive index layers in all the laminates is preferably within the above-described preferred range. However, in this case, the refractive index layer constituting the uppermost layer or the lowermost layer of the induced multilayer film may be constituted outside the above-described preferable range.

The optical reflection film of the present embodiment has optical properties such that the visible light transmittance shown in JIS R3106-1998 is preferably 50% or more, more preferably 75% or more, and even more preferably 85% or more. In addition, it is preferable that the region having a wavelength of 900nm to 1400nm has a reflectance of more than 50%.

The number of refractive index layers (total number of high refractive index layers and low refractive index layers) of the dielectric multilayer film is, for example, 6 to 500, preferably 6 to 300 from the above viewpoint. In particular, when the film is produced by a wet film-forming method, the number of the layers is preferably 6 to 50, more preferably 8 to 40, still more preferably 9 to 30, and particularly preferably 11 to 31. When the number of refractive index layers in the dielectric multilayer film is within the above range, excellent heat insulating performance and transparency, suppression of film peeling or chapping, and the like can be realized, and therefore, such is preferable. When the dielectric multilayer film has a plurality of high refractive index layers and/or low refractive index layers, the high refractive index layers and/or the low refractive index layers may be the same or different.

The thickness of each 1 layer of the high refractive index layer is preferably 20 to 800nm, and more preferably 50 to 500 nm. In addition, the thickness of each 1 layer of the low refractive index layer is preferably 20 to 800nm, and more preferably 50 to 500 nm.

Here, when the thickness of each 1 layer is measured, there is a case where a clear interface is not present at the boundary between the high refractive index layer and the low refractive index layer, and the composition changes continuously. In the interface region where the composition continuously changes, when the maximum refractive index-minimum refractive index is Δ n, the position of the minimum refractive index + Δ n/2 between 2 layers is regarded as the layer interface.

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 distribution of the metal oxide particles. The metal oxide concentration distribution can be observed by etching from the surface in the depth direction by a sputtering method, sputtering at a speed of 0.5nm/min with the outermost surface set to 0nm by an XPS surface analyzer, and measuring the atomic composition ratio. Alternatively, the atomic composition ratio may be measured by an XPS surface analyzer for a cut surface by cutting the laminated film.

The XPS surface analyzer is not particularly limited, and any machine type can be used. As the XPS surface analyzer, for example, ESCALB-200R manufactured by VGScientifications may be used. The X-ray anode was measured with an output of 600W (acceleration voltage 15kV, emission current 40mA) using Mg.

[ adhesive layer ]

The optical reflection film of the present invention may have an adhesive layer. The adhesive layer is usually provided on the surface opposite to the substrate of the dielectric multilayer film, and a known release paper or a separator may be further provided. The technical scheme of the adhesive layer is not particularly limited, and for example, a dry laminating agent, a wet laminating agent, an adhesive, a heat sealing agent, a hot melt agent, and the like can be used.

Examples of the adhesive include polyester adhesives, polyurethane adhesives, polyvinyl acetate adhesives, acrylic adhesives, and nitrile rubbers.

In the case where the optical reflection film of the present invention is bonded to a window glass, a bonding method in which water is sprayed to the window and the adhesive layer of the optical reflection film is bonded to the glass surface in a wet state, that is, a so-called water bonding method, is preferably used from the viewpoints of rearrangement, position correction, and the like. Therefore, an acrylic adhesive having a weak adhesive force is preferably used under a wet condition in the presence of water.

The acrylic pressure-sensitive adhesive to be used may be any of solvent-based pressure-sensitive adhesives and emulsion-based pressure-sensitive adhesives, but from the viewpoint of easy improvement of the adhesive strength, a solvent-based pressure-sensitive adhesive is preferable, and among them, a solvent-based pressure-sensitive adhesive obtained by solution polymerization is preferable. As raw materials for producing such solvent-based acrylic adhesives by solution polymerization, for example, acrylic esters such as ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and octyl acrylate can be given as main monomers of the skeleton, vinyl acetate, acrylonitrile, styrene, and methyl methacrylate can be given as comonomers for improving cohesive force, and methacrylic acid, acrylic acid, itaconic acid, hydroxyethyl methacrylate, and glycidyl methacrylate can be given as functional group-containing monomers for further promoting crosslinking and imparting stable adhesive force, and for maintaining adhesive force to some extent even in the presence of water. In the pressure-sensitive adhesive layer, a high tackiness is particularly required as the main polymer, and therefore, a substance having a low glass transition temperature (Tg) such as butyl acrylate is particularly useful.

Examples of commercially available products of the acrylic pressure-sensitive adhesive include: COPONYL (registered trademark) series (manufactured by Nippon synthetic chemical industries, Ltd.), and the like.

The adhesive layer may contain additives such as a stabilizer, a surfactant, an ultraviolet absorber, a flame retardant, an antistatic agent, an antioxidant, a heat stabilizer, a lubricant, a filler, a colorant, and an adhesion adjuster. In particular, when used for window attachment, the addition of an ultraviolet absorber can be effectively used to suppress deterioration of the optical reflective film due to ultraviolet rays.

The method of applying the adhesive is not particularly limited, and any known method may be used, and examples thereof include a bar coating method, a dispensing coating method, a comma coating method, a gravure roll coating method, a blade coating method, a spray coating method, an air knife coating method, a dip coating method, a transfer coating method, and the like, and the method may be used alone or in combination. In these methods, a solution of a solvent capable of dissolving the binder or a coating solution obtained by dispersing the binder may be applied as appropriate, and a known solvent may be used.

In addition, the thickness of the adhesive layer is preferably in the range of about 1 to 100 μm in general from the viewpoint of the adhesive effect, the drying rate, and the like.

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

The adhesive layer may be formed by applying the above coating method directly to the dielectric multilayer film, or by applying the coating method to a release film at a time and drying the release film, and then laminating the dielectric multilayer film to transfer the adhesive. In this case, the drying temperature is preferably as low as possible in terms of residual solvent, and therefore, the drying temperature or time is not particularly limited, and a drying time of 10 seconds to 5 minutes at a temperature of 50 to 150 ℃ may be preferred.

[ hard coating layer ]

The optical reflection film of the present invention can be used as a surface protective layer for improving abrasion resistance by laminating a hard coat layer containing a resin cured by heat, ultraviolet rays, or the like. For example, a preferable example is a method in which a dielectric multilayer film and an adhesive layer are laminated in this order on a substrate surface, and a hard coat layer is further coated on the substrate surface on the side opposite to the side where these layers are laminated.

The curable resin used for the hard coat layer includes a thermosetting resin and an ultraviolet curable resin, and from the viewpoint of ease of molding, an ultraviolet curable resin is preferable, and among them, an ultraviolet curable resin having a pencil hardness of at least 2H is more preferable. Such curable resins may be used alone or in combination of 2 or more.

Examples of the ultraviolet curable resin include: (meth) acrylate, urethane acrylate, polyester acrylate, epoxy resin, oxetane resin, and these may also be used as a solvent-free resin composition.

When the ultraviolet curable resin is used, a photopolymerization initiator is preferably added to accelerate curing.

As the photopolymerization initiator, acetophenones, benzophenones, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2, 3-dialkyldione compounds, disulfide compounds, thiuram compounds, fluoroamine compounds, and the like can be used. Specific examples of the photopolymerization initiator include: acetophenones such as 2,2 '-diethoxyacetophenone, p-dimethylacetophenone, 1-hydroxycyclohexylphenyl ketone, 1-hydroxydimethylphenyl ketone, 2-methyl-4' -methylthio-2-morpholinoacetone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, benzoins such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzyl dimethyl ketal, benzophenones such as benzophenone, 2,4 '-dichlorobenzophenone, 4' -dichlorobenzophenone and p-chlorobenzophenone, 2,4, 6-trimethylbenzoyldiphenylphosphine oxide, anthraquinones and thioxanthones. These photopolymerization initiators may be used alone, or 2 or more kinds may be used in combination, or a melt mixture. In particular, acetophenones are preferably used from the viewpoint of stability of the curable composition, polymerization reactivity, and the like.

Examples of such photopolymerization initiators include IRGACURE (registered trademark) 819, IRGACURE 184, IRGACURE 907, and IRGACURE651, which are commercially available from basf japan, for example.

From the viewpoint of improving the hard coat property and improving the transparency of the optical reflection film, the thickness of the hard coat layer is preferably 0.1 to 50 μm, and more preferably 1 to 20 μm.

The method for forming the hard coat layer is not particularly limited, and examples thereof include a method in which a hard coat layer coating liquid containing the above-mentioned components is prepared, then the coating liquid is applied by a wire bar or the like, and the coating liquid is cured by heat and/or UV to form the hard coat layer.

[ other layers ]

The optical reflection film of the present invention may have a layer (other layer) other than the above-described layers. For example, as the other layer, an intermediate layer may be provided. Here, the "intermediate layer" means a layer between the substrate and the dielectric multilayer film or a layer between the substrate 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, polyurethane resin, and the like, and those having low compatibility with additives and low Tg are preferable, and any resin can be used as long as the conditions are satisfied. The glass transition temperature (Tg) of the intermediate layer is preferably in the range of 30 to 90 ℃ because sufficient weather resistance can be obtained if it is 30 to 120 ℃.

[ method for producing optical reflective film ]

The method for producing the optical reflection film of the present invention is not particularly limited, and any method may be used as long as at least 1 unit composed of a high refractive index layer and a low refractive index layer can be formed on a substrate, and at least 1 of the high refractive index layer and the low refractive index layer is the above-described layer containing the water-dispersible hydrophobic resin.

Specifically, it is preferable to form a laminate (dielectric multilayer film) by alternately applying and drying a high refractive index layer and a low refractive index layer. Specifically, the following modes can be mentioned: (1) a method of forming an optical reflective film by applying a high refractive index layer coating solution on a substrate and drying the coating solution to form a high refractive index layer, and then applying a low refractive index layer coating solution and drying the coating solution to form a low refractive index layer; (2) a method of forming an optical reflective film by applying a low refractive index layer coating liquid on a substrate and drying the low refractive index layer coating liquid to form a low refractive index layer, and then applying a high refractive index layer coating liquid and drying the high refractive index layer coating liquid to form a high refractive index layer; (3) a method of forming an optical reflective film including a high refractive index layer and a low refractive index layer by alternately and successively applying a high refractive index layer coating liquid and a low refractive index layer coating liquid on a substrate and then drying the layers; (4) and a method of simultaneously coating a high refractive index layer coating liquid and a low refractive index layer coating liquid on a substrate in a multiple layer manner and drying the same to form an optical reflection film including a high refractive index layer and a low refractive index layer. Among these, the method of (4) above is preferable as a simpler production process. That is, the method for producing an optical reflection film of the present invention preferably includes laminating the high refractive index layer and the low refractive index layer by a simultaneous double layer coating method.

In the case of simultaneous double layer coating, since the layers are stacked in an undried liquid state, interlayer mixing and the like are more likely to occur. However, when the water-soluble resin is a polyvinyl alcohol resin, the polyvinyl alcohol resin contained in the high refractive index layer and the polyvinyl alcohol resin contained in the low refractive index layer have different degrees of saponification, and it is known that the polyvinyl alcohol resins having different degrees of saponification have low compatibility. Therefore, even if the layers are slightly mixed when the high refractive index layer and the low refractive index layer are stacked in an undried liquid state, when water as a solvent is evaporated and concentrated in the drying process, polyvinyl alcohol resins having different degrees of saponification are phase-separated from each other, and a force for minimizing the area of the interface of each layer acts, so that the interphase mixing is suppressed, and the disturbance of the interface is reduced. Therefore, an optical reflective film having excellent light reflection characteristics in a desired wavelength region and less haze can be obtained.

As the coating method, for example, a roll coating method, a rod coating method, an air knife coating method, a spray coating method, a curtain coating method, a slide bead coating method using a hopper described in U.S. Pat. No. 2,761,419 and the same japanese patent No. 2,761,791, an extrusion coating method, or the like is preferably used.

The solvent used for preparing the high refractive index layer coating liquid and the low refractive index layer coating liquid is not particularly limited, and water, an organic solvent, or a mixed solvent thereof is preferable. In the present invention, an aqueous solvent may be used in order to use the water-soluble resin. The aqueous solvent is preferable in terms of productivity and environmental conservation because it does not require a large-scale production facility as compared with the case of using an organic solvent.

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, ethers such as diethyl ether, 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 2 or more. From the viewpoint of the environment, the simplicity of operation, and the like, the solvent of the coating liquid is preferably an aqueous solvent, more preferably water, or a mixed solvent of water and methanol, ethanol, or ethyl acetate, and particularly preferably water.

When a mixed solvent of water and a small amount of an organic solvent is used, the content of water in the mixed solvent is preferably 80 to 99.9% by mass, and more preferably 90 to 99.5% by mass, with the total amount of the mixed solvent being 100% by mass. This is because, by setting the amount to 80% by mass or more, the volume change due to the volatilization of the solvent can be reduced, the operation can be improved, and by setting the amount to 99.9% by mass or less, the homogeneity at the time of liquid addition can be increased, and stable liquid properties can be obtained.

The concentration of the water-soluble resin in the high refractive index layer coating liquid is preferably 0.5 to 10 mass%. The concentration of the metal oxide particles in the high refractive index layer coating liquid is preferably 1 to 50 mass%.

The concentration of the water-soluble resin in the low refractive index layer coating liquid is preferably 0.5 to 10 mass%. The concentration of the metal oxide particles in the low refractive index layer coating liquid is preferably 1 to 50 mass%.

The method for preparing the high refractive index layer coating liquid and the low refractive index layer coating liquid is not particularly limited, and examples thereof include a method in which metal oxide particles, a water-soluble resin, a curing agent, and the like are added to an aqueous solvent and stirred and mixed. In this case, the order of addition of the components is not particularly limited, and the components may be added and mixed sequentially while stirring, or may be added and mixed at once while stirring.

When at least 1 of the high refractive index layers is a layer containing a water-dispersible hydrophobic resin, the water-dispersible hydrophobic resin may be added to the high refractive index layer coating solution so that the final solid content concentration falls within a predetermined range, thereby preparing a layer coating solution containing a water-dispersible hydrophobic resin (a high refractive index layer coating solution containing a water-dispersible hydrophobic resin). By applying the layer coating liquid containing the water-dispersible hydrophobic resin and drying it, a layer containing the water-dispersible hydrophobic resin which functions as a high refractive index layer can be obtained.

Similarly, when at least 1 layer of the low refractive index layer is a layer containing a water-dispersible hydrophobic resin, the water-dispersible hydrophobic resin may be added to the low refractive index layer coating solution described above so that the final solid content concentration is within a predetermined range, thereby preparing a coating solution for the layer containing the water-dispersible hydrophobic resin (a low refractive index layer coating solution containing a water-dispersible hydrophobic resin). By applying and drying the layer coating liquid containing the water-dispersible hydrophobic resin, a layer containing the water-dispersible hydrophobic resin which functions as a low refractive index layer can be obtained.

In the coating liquid of the layer containing a water-dispersible hydrophobic resin, the concentration of the water-dispersible hydrophobic resin is not particularly limited, and is adjusted so that the content (solid content) of the water-dispersible hydrophobic resin in the layer containing a water-dispersible hydrophobic resin is within the above range.

As described above, a preferred embodiment of the optical reflective film of the present invention includes an anionic emulsion resin and an anionic surfactant in the layer containing a water-dispersible hydrophobic resin. Therefore, the optical reflection film of the present invention preferably comprises: a step of dissolving or dispersing a water-soluble resin, an anionic surfactant, and an anionic emulsion resin in an aqueous solvent to prepare a coating liquid; a step of forming the layer containing the water-dispersible hydrophobic resin by applying the coating liquid.

In the case of using the sliding bead coating method, the temperature of the high refractive index layer coating liquid and the low refractive index layer coating liquid at the time of simultaneous double layer coating is preferably in the temperature range of 25 to 60 ℃, and more preferably in the temperature range of 30 to 45 ℃. When the curtain coating method is used, the temperature is preferably in the range of 25 to 60 ℃ and more preferably in the range of 30 to 45 ℃.

The viscosity of the high refractive index layer coating liquid and the low refractive index layer coating liquid when simultaneous double layer coating is performed is not particularly limited. However, in the case of using the sliding bead coating method, the preferable temperature range of the coating liquid is preferably 5 to 160mPa · s, and more preferably 60 to 140mPa · s. In the case of using the curtain coating method, the temperature of the coating liquid is preferably in the range of 5 to 1200mPa · s, and more preferably in the range of 25 to 500mPa · s. If the viscosity is in such a range, simultaneous multilayer coating can be efficiently performed.

The viscosity at 15 ℃ of the coating liquid is preferably 100 mPas or more, more preferably 100 to 30,000 mPas, and still more preferably 2,500 to 30,000 mPas.

The conditions of the coating and drying methods are not particularly limited, and for example, in the case of a sequential coating method, first, any coating liquid of a high refractive index layer coating liquid and a low refractive index layer coating liquid heated to 30 to 60 ℃ is coated on a substrate and dried to form a layer, and then, the other coating liquid is coated on the layer and dried to form a laminated film precursor (unit). Next, the coating and drying are successively performed by the above-described method, and the number of units required for exhibiting desired optical reflection performance is stacked to obtain a stacked film precursor. In the drying, the formed coating film is preferably dried at 30 ℃ or higher. For example, the drying is preferably performed at a wet bulb temperature of 5 to 50 ℃ and a film surface temperature of 5 to 100 ℃ (preferably 10 to 50 ℃), and for example, the drying is performed by blowing warm air at 40 to 60 ℃ for 1 to 5 seconds. As a drying method, warm air drying, infrared drying, or microwave drying may be used. Further, the drying in the multistage process is preferable to the drying in the single process, and the temperature in the constant-speed drying section < the temperature in the deceleration drying section is more preferable. The temperature range of the constant-speed drying section is preferably 30 to 60 ℃ and the temperature range of the deceleration drying section is preferably 50 to 100 ℃.

In addition, the conditions of the coating and drying method in the case of simultaneous double layer coating are preferably such that the high refractive index layer coating liquid and the low refractive index layer coating liquid are heated to 30 to 60 ℃, the simultaneous double layer coating of the high refractive index layer coating liquid and the low refractive index layer coating liquid is performed on the substrate, and then the temperature of the formed coating film is once cooled to preferably 1 to 15 ℃ (fixed), and thereafter, the coating film is dried at 10 ℃ or higher. More preferably, the drying conditions are that the wet bulb temperature is 5-50 ℃ and the membrane surface temperature is 10-50 ℃. For example, the drying is carried out by blowing warm air at 40 to 80 ℃ for 1 to 5 seconds. In addition, as a cooling method immediately after coating, a horizontal fixing method is preferably used from the viewpoint of improving the uniformity of the formed coating film.

Here, the fixation means a step of increasing the viscosity of the coating composition by a means such as reducing the temperature by blowing cold air or the like to the coating film, thereby reducing the fluidity of the substance between the layers and in the layers, or gelling the substance separately. The state in which no substance was adhered to the finger when the coating film was blown with cold air from the surface and pressed against the surface of the coating film with the finger was defined as the state in which the fixation was completed.

The time (fixation time) from the time of application to the end of fixation by blowing cold air is preferably within 5 minutes, more preferably within 2 minutes. The lower limit time is not particularly limited, and a time of 45 seconds or more is preferably used. The step of fixing may not be provided as long as the intermediate layer between the high refractive index layer and the low refractive index layer rapidly increases in elasticity.

The fixing time can be adjusted by adjusting the concentration of the polyvinyl alcohol resin or the concentration of the metal oxide particles, or by adding other components such as various known gelling agents such as gelatin, pectin, agar, carrageenan, and gellan gum.

The temperature of the cold air is preferably 0-25 ℃, and more preferably 5-10 ℃. The time for which the coating film is exposed to the cold air depends on the conveying speed of the coating film, but is preferably 10 to 360 seconds, more preferably 10 to 300 seconds, and still more preferably 10 to 120 seconds.

The high refractive index layer coating liquid and the low refractive index layer coating liquid may be applied so that the coating thicknesses thereof become the preferred dry thicknesses described above.

< optical Reflector >

The optical reflection film of the present invention can be applied to a wide range of fields. Accordingly, one embodiment of the present invention is an optical reflector in which the optical reflective film is provided on at least one surface of the substrate. For example, a film for window attachment such as a heat ray reflection film which is attached to a device (substrate) exposed to sunlight for a long period of time such as a window for outdoor use of a building, a window for an automobile, or the like and which imparts a heat ray reflection effect, a film for a plastic greenhouse for agricultural use, or the like is used mainly for the purpose of improving weather resistance. The optical reflection film of the present invention is particularly suitable for a member bonded to a substrate such as glass or a resin instead of glass via the above-mentioned adhesive layer.

Specific examples of the substrate include: glass, polycarbonate resin, polysulfone resin, acrylic resin, polyolefin resin, polyether resin, polyester resin, polyamide resin, polythioether resin, unsaturated polyester resin, epoxy resin, melamine resin, phenol resin, diallyl phthalate resin, polyimide resin, polyurethane resin, polyvinyl acetate resin, polyvinyl alcohol resin, styrene resin, vinyl chloride resin, metal plate, ceramic, and the like. The type of the resin may be any of a thermoplastic resin, a thermosetting resin, and an ionizing radiation curable resin, and 2 or more of these may be used in combination. The substrate can be produced by a known method such as extrusion molding, calender molding, injection molding, blow molding, compression molding, or the like. The thickness of the substrate is not particularly limited, and is usually 0.1mm to 5 cm.

When the adhesive layer for bonding the optical reflective film and the substrate is bonded to a window glass or the like, the optical reflective film is preferably provided so as to be positioned on the sunlight (heat ray) incident surface side. When the optical reflective film is sandwiched between the window glass and the substrate, the optical reflective film can be sealed with a surrounding gas such as moisture, and is preferable in terms of durability. The optical reflection film of the present invention is preferably used for outdoor or vehicle exterior (for exterior application) because it has environmental durability.

Examples

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the examples. In the examples, "part(s)" or "%" are used, but unless otherwise specified, "part(s) by mass" or "% by mass" is used. Unless otherwise specified, each operation was carried out at room temperature (25 ℃ C.).

Production of optical reflective film

(example 1)

Preparation of high refractive index layer coating liquid 1

The high refractive index layer coating liquid 1 was prepared according to the following procedure.

(preparation of silica-attached Titania Sol)

First, a silica-attached titania sol containing rutile type titania was prepared as follows.

At 150.5 parts by mass of a titanium oxide sol (SRD-W, volume average particle diameter: 5nm, rutile titanium dioxide particle, made by Sakai chemical industries Co., Ltd.) was added with 2 parts by mass of pure water, and then heated to 90 ℃. Then, an aqueous silicic acid solution (soda 4 (manufactured by Nippon chemical industries Co., Ltd.) was slowly added and diluted to form SiO₂0.5 mass% solution), followed by heating at 175 ℃ for 18 hours in an autoclave, cooling, and concentrating with an ultrafiltration membrane to obtain SiO having a solid content of 6 mass% relative to titania₂A titania sol (hereinafter referred to as a silica-attached titania sol) attached to the surface (volume average particle diameter: 9 nm).

(preparation of high refractive index layer coating liquid 1)

A high refractive index layer coating solution 1 was prepared by adding 48 parts by mass of an aqueous citric acid solution (1.92% by mass) to 113 parts by mass of the silica-attached titanium dioxide sol (20% by mass) obtained in the above-described procedure, adding 113 parts by mass of polyvinyl alcohol (PVA-117, average polymerization degree 1700, saponification degree: 97.5 to 99 mol%, 8% by mass), stirring, and finally adding 0.4 part by mass of a 5% by mass aqueous solution of a surfactant (SOFTZOLINE LSB-R, manufactured by Kawa Kawakaki Kaisha).

The refractive index of the film formed by applying the high refractive index layer coating liquid 1 was 1.80. The refractive index was measured as follows (the same applies hereinafter).

Measurement of refractive index of single layer of each layer

In order to measure the refractive index, a sample obtained by coating the high refractive index layer coating liquid 1 on a substrate in a single layer was prepared, and the sample was cut into 10cm × 10cm, and then the refractive index was determined by the following method. The surface (back surface) of each sample on the side opposite to the measurement surface was roughened using a spectrophotometer U-4100 (solid sample measurement system) manufactured by hitachi, and then light absorption treatment was performed with black spray to prevent reflection of light from the back surface, and the reflectance in the visible light region (400nm to 700nm) was measured under a condition of regular reflection at 5 °, and the refractive index was determined from the results.

Preparation of coating liquid for Low refractive index layer 1

A low refractive index layer coating liquid 1 was prepared by heating 31 parts by mass of a 10 mass% aqueous solution of acidic colloidal silica (SNOWTEX (registered trademark) OXS, primary particle diameter: 5.4nm, manufactured by Nissan chemical industries Co., Ltd.) to 40 ℃ and adding 3 parts by mass of a 3 mass% aqueous solution of boric acid, and further adding 39 parts by mass of a 6 mass% aqueous solution of polyvinyl alcohol (PVA-224, average degree of polymerization: 2400, degree of saponification: 87 to 89 mol%, manufactured by Kokushii Co., Ltd.) and 1 part by mass of a 5 mass% aqueous solution of a surfactant (SOFTZOLINE LSB-R, manufactured by Kawa Kaishi) as a water-soluble resin at 40 ℃.

The film obtained by applying the low refractive index layer coating liquid 1 had a refractive index of 1.50.

Preparation of coating liquid 1 for Low refractive index layer containing Water-dispersible hydrophobic resin

13 parts by mass of a 10 mass% aqueous solution of acidic colloidal silica (SNOWTEX (registered trademark) OXS, primary particle diameter: 5.4nm, manufactured by Nissan chemical industries Co., Ltd.) was heated to 40 ℃ and 3 parts by mass of a 3 mass% aqueous solution of boric acid was added, and further 35 parts by mass of a 6 mass% aqueous solution of polyvinyl alcohol (PVA-224, average degree of polymerization: 2400, degree of saponification: 87 to 89 mol%, manufactured by Kokushii Co., Ltd.) as a water-soluble resin was sequentially added at 40 ℃, a low refractive index layer coating solution 1 containing a water-dispersible hydrophobic resin was prepared from 3 parts by mass of a 6% by mass aqueous solution of a water-dispersible polyurethane resin (ADEKA bongihter HUX-830, 100nm average particle diameter, manufactured by ADEKA corporation) and 1 part by mass of a 5% by mass aqueous solution of an anionic surfactant (NoigenXL-40, manufactured by first industrial pharmaceutical co.

The water-dispersed polyurethane resin was confirmed to be an anionic resin by measuring the Z potential. Specific measurement methods are as follows.

The device comprises the following steps: zetasizer-nano ZSP manufactured by Malvern corporation

The measurement method comprises the following steps: electrophoretic light scattering method

Sample adjustment: the water-dispersible hydrophobic resin was diluted to a 1% by mass solution.

The refractive index of the film obtained by applying the low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin was 1.50.

Production of optical reflective film 1

The high refractive index layer coating liquid 1, the low refractive index layer coating liquid 1, and the low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin prepared in the above were each adjusted to 40 ℃ using a slide hopper coating apparatus capable of performing 19-layer heavy layer coating. On a polyethylene terephthalate film (A4300: double-sided easy-to-adhere layer manufactured by Toyobo Co., Ltd.) having a thickness of 50 μm and a width of 160mm as a base material heated to 40 ℃, the lowermost layer and the uppermost layer were low refractive index layers, the 11 th layer from the base material side was a low refractive index layer containing a water-dispersible hydrophobic resin, and a total of 19 layers were alternately applied in a double layer manner so that the film thickness of the low refractive index layer and the low refractive index layer containing a water-dispersible hydrophobic resin at the time of drying was 150nm for each layer and the film thickness of the high refractive index layer was 130nm for each layer. Immediately after the application, the coating was fixed (thickened) by blowing cold air at 10 ℃.

After the fixation (thickening) was completed, the optical reflection film 1 of example 1 was prepared by blowing hot air at 60 ℃ and drying the film, and the total of the layers was 19.

In the measurement (confirmation) of the film thickness, the optical reflection film sample was cut, and the high refractive index material (TiO) was measured with the XPS surface analyzer for the cut surface₂) And a low refractive index material (SiO)₂) The film thickness of each layer can be confirmed to be secured by the presence amount of (b).

(example 2)

Preparation of coating liquid 2 for Low refractive index layer containing Water-dispersible hydrophobic resin

A low refractive index layer coating solution 2 containing a water-dispersible hydrophobic resin was prepared in the same manner as in the low refractive index layer coating solution 1 containing a water-dispersible hydrophobic resin except that 18 parts by mass of a 10 mass% aqueous solution of acidic colloidal silica, 6 parts by mass of a 6 mass% aqueous solution of polyvinyl alcohol, and 47 parts by mass of a 6 mass% aqueous solution of a water-dispersible urethane resin.

The film coated with the low refractive index layer coating liquid 2 containing the water-dispersible hydrophobic resin had a refractive index of 1.50.

Production of optical reflective film 2

An optical reflection film 2 was produced in the same manner as in example 1, except that in example 1 (production of optical reflection film 1), the low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin was changed to the low refractive index layer coating liquid 2 containing the water-dispersible hydrophobic resin prepared as described above.

(example 3)

Preparation of coating liquid 3 for Low refractive index layer containing Water-dispersible hydrophobic resin

In example 1 (preparation of low refractive index layer coating liquid 1 containing a dispersible hydrophobic resin), a low refractive index layer coating liquid 3 containing a water-dispersible hydrophobic resin was prepared in the same manner as in example 1 except that 19 parts by mass of a 10 mass% aqueous solution of acidic colloidal silica, 38 parts by mass of a 6 mass% aqueous solution of polyvinyl alcohol, and 18 parts by mass of a 6 mass% aqueous solution of a water-dispersible urethane resin.

The refractive index of the film obtained by applying the low refractive index layer coating liquid 3 containing the water-dispersible hydrophobic resin was 1.50.

Production of optical reflective film 3

An optical reflection film 3 was produced in the same manner as in example 1, except that in example 1 (production of optical reflection film 1), the low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin was changed to the low refractive index layer coating liquid 3 containing the water-dispersible hydrophobic resin prepared as described above.

(example 4)

Preparation of coating liquid 4 for Low refractive index layer containing Water-dispersible hydrophobic resin

In the same manner as in example 1 except that 19 parts by mass of a 10 mass% aqueous solution of acidic colloidal silica, 38 parts by mass of a 6 mass% aqueous solution of polyvinyl alcohol, 18 parts by mass of a 6 mass% aqueous solution of a water-dispersible urethane resin, and 1 part by mass of a 5 mass% aqueous solution of an anionic surfactant (NoigenXL-40, manufactured by first industrial pharmaceutical company) were used in example 1 (preparation of low refractive index layer coating liquid 1 containing a dispersible hydrophobic resin), 1 part by mass of a 5 mass% aqueous solution of an anionic surfactant (litenol NF-08, manufactured by first industrial pharmaceutical company) was used, low refractive index layer coating liquid 4 containing a water-dispersible hydrophobic resin was prepared.

The refractive index of the film coated with the low refractive index layer coating liquid 4 containing the water-dispersible hydrophobic resin was 1.50.

Production of optical reflection film 4

An optical reflection film 4 was produced in the same manner as in example 1, except that in example 1 (production of optical reflection film 1), the low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin was changed to the low refractive index layer coating liquid 4 containing the water-dispersible hydrophobic resin prepared as described above.

(example 5)

Preparation of coating liquid 5 for Low refractive index layer containing Water-dispersible hydrophobic resin

In example 1 (preparation of coating liquid 1 for low refractive index layer containing dispersible hydrophobic resin), 3 parts by mass of a 6% by mass aqueous solution of water-dispersible polyurethane resin (ADEKA bonghher HUX-830, average particle size 100nm, manufactured by ADEKA corporation) was changed to 3 parts by mass of a 6% by mass aqueous solution of water-dispersible acrylic resin (AE-116, average particle size 80nm, manufactured by E-TEC corporation), 1 part by mass of a 5% by mass aqueous solution of anionic surfactant (NoigenXL-40, manufactured by first industrial pharmaceutical co., ltd) was changed to 1 part by mass of a 5% by mass aqueous solution of anionic surfactant (HITENOL NF-08, manufactured by first industrial pharmaceutical co., ltd.), in the same manner as in example 1, a low refractive index layer coating solution 5 containing a water-dispersible hydrophobic resin was prepared.

The refractive index of the film coated with the low refractive index layer coating liquid 5 containing the water-dispersible hydrophobic resin was 1.50.

The water-dispersible acrylic resin was confirmed to be an anionic resin by measuring the zeta potential. The specific measurement method is the same as that in the above-mentioned water-dispersed polyurethane resin.

Production of optical reflection film 5

An optical reflection film 5 was produced in the same manner as in example 1, except that in example 1 (production of optical reflection film 1), the low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin was changed to the low refractive index layer coating liquid 5 containing the water-dispersible hydrophobic resin prepared as described above.

(example 6)

Preparation of coating liquid 6 for Low refractive index layer containing Water-dispersible hydrophobic resin

In the same manner as in example 1 except that 3 parts by mass of a 6% by mass aqueous dispersion urethane resin solution was changed to 3 parts by mass of a 6% by mass aqueous dispersion acrylic resin solution (AE-120A, average particle diameter 55nm, manufactured by E-TEC), and 1 part by mass of an aqueous solution of an anionic surfactant was changed to 1 part by mass of a 5% by mass aqueous solution of an anionic surfactant (HITENOL NF-08, manufactured by seiko corporation), in example 1 (preparation of low refractive index layer coating liquid 1 containing a dispersible hydrophobic resin), a low refractive index layer coating liquid 6 containing a water dispersible hydrophobic resin was prepared.

The refractive index of the film coated with the low refractive index layer coating liquid 6 containing the water-dispersible hydrophobic resin was 1.50.

Production of optical reflection film 6

An optical reflection film 6 was produced in the same manner as in example 1, except that in example 1 (production of optical reflection film 1), the low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin was changed to the low refractive index layer coating liquid 6 containing the water-dispersible hydrophobic resin prepared as described above.

(example 7)

Preparation of coating liquid 7 for Low refractive index layer containing Water-dispersible hydrophobic resin

In example 1 (preparation of low refractive index layer coating solution 1 containing a dispersible hydrophobic resin), 18 parts by mass of a 6 mass% aqueous solution of acidic colloidal silica, 6 parts by mass of a 6 mass% aqueous solution of polyvinyl alcohol, 3 parts by mass of a 6 mass% aqueous solution of a water-dispersible polyurethane resin (ADEKA bongighher HUX-830, average particle diameter 100nm, manufactured by ADEKA corporation) was changed to 47 parts by mass of a 6 mass% aqueous solution of a water-dispersible acrylic resin (AE-120A, average particle diameter 55nm, manufactured by E-TEC), 1 part by mass of a 5 mass% aqueous solution of an anionic surfactant (noigenl-40, manufactured by first industrial pharmaceutical company) was changed to 1 part by mass of a 5 mass% aqueous solution of an anionic surfactant (HITENOL NF-08, manufactured by first industrial pharmaceutical company), in the same manner as in example 1 except for this, a low refractive index layer coating solution 7 containing a water-dispersible hydrophobic resin was prepared.

The refractive index of the film coated with the low refractive index layer coating liquid 7 containing the water-dispersible hydrophobic resin was 1.50.

Production of optical reflection film 7

An optical reflection film 7 was produced in the same manner as in example 1, except that in example 1 (production of optical reflection film 1), the low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin was changed to the low refractive index layer coating liquid 7 containing the water-dispersible hydrophobic resin prepared as described above.

(example 8)

Preparation of coating liquid 8 for Low refractive index layer containing Water-dispersible hydrophobic resin

In example 1 (preparation of coating solution 1 for low refractive index layer containing dispersible hydrophobic resin), 19 parts by mass of a 10 mass% aqueous solution of acidic colloidal silica, 38 parts by mass of a 6 mass% aqueous solution of polyvinyl alcohol, 3 parts by mass of a 6 mass% aqueous solution of water-dispersed urethane resin (ADEKA bongighher HUX-830, average particle diameter 100nm, manufactured by ADEKA corporation) was changed to 18 parts by mass of a 6 mass% aqueous solution of water-dispersed acrylic resin (AE-120A, average particle diameter 55nm, manufactured by E-TEC), 1 part by mass of a 5 mass% aqueous solution of anionic surfactant (noignexl-40, manufactured by first industrial pharmaceutical company) was changed to 1 part by mass of a 5 mass% aqueous solution of anionic surfactant (HITENOL NF-08, manufactured by first industrial pharmaceutical company), except for this, a low refractive index layer coating solution 8 containing a water-dispersible hydrophobic resin was prepared in the same manner as in example 1.

The refractive index of the film coated with the low refractive index layer coating liquid 8 containing the water-dispersible hydrophobic resin was 1.50.

Production of optical reflection film 8

An optical reflection film 8 was produced in the same manner as in example 1, except that in example 1 (production of optical reflection film 1), the low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin was changed to the low refractive index layer coating liquid 8 containing the water-dispersible hydrophobic resin prepared as described above.

(example 9)

Preparation of coating liquid 9 for Low refractive index layer containing Water-dispersible hydrophobic resin

In example 1 (preparation of low refractive index layer coating liquid 1 containing a dispersible hydrophobic resin), a low refractive index layer coating liquid 9 containing a water-dispersible hydrophobic resin was prepared in the same manner as in example 1 except that 19 parts by mass of a 10 mass% aqueous solution of acidic colloidal silica, 38 parts by mass of a 6 mass% aqueous solution of polyvinyl alcohol, and 3 parts by mass of a 6 mass% aqueous solution of a water-dispersible urethane resin (ADEKA bongighher HUX-830, average particle diameter 100nm, manufactured by ADEKA corporation) were changed to 18 parts by mass of a 6 mass% aqueous solution of a water-dispersible acrylic resin (AE-120A, average particle diameter 55nm, manufactured by E-TEC).

The film coated with the low refractive index layer coating liquid 9 containing the water-dispersible hydrophobic resin had a refractive index of 1.50.

Production of optical reflective film 9

An optical reflection film 9 was produced in the same manner as in example 1, except that in example 1 (production of optical reflection film 1), the low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin was changed to the low refractive index layer coating liquid 9 containing the water-dispersible hydrophobic resin prepared as described above.

(example 10)

Production of optical reflective film 10

In the above example 1 (preparation of optical reflection film 1), an optical reflection film 10 was prepared in the same manner as in example 1 except that the coating liquid for forming the low refractive index layer containing the water-dispersible hydrophobic resin was changed from the low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin to the low refractive index layer coating liquid 8 containing the water-dispersible hydrophobic resin, and the 19 th layer from the substrate side was used as the low refractive index layer containing the water-dispersible hydrophobic resin instead of the 11 th layer from the substrate side.

(example 11)

Preparation of coating liquid 10 for Low refractive index layer containing Water-dispersible hydrophobic resin

In example 1 (preparation of coating solution 1 for low refractive index layer containing dispersible hydrophobic resin), 19 parts by mass of a 10 mass% aqueous solution of acidic colloidal silica was changed to 38 parts by mass of a 6 mass% aqueous solution of polyvinyl alcohol (JC-40, average degree of polymerization: 4000, degree of saponification: 99 mol%, manufactured by JAPAN VAM & POVAL), 3 parts by mass of a 6 mass% aqueous solution of water-dispersible polyurethane resin (ADEKA bonghher x-830, average particle size: 100nm, manufactured by ADEKA corporation) was changed to 18 parts by mass of a 6 mass% aqueous solution of water-dispersible acrylic resin (AE-120A, average particle size: 55nm, manufactured by E-TEC), and 1 part by mass of a 5 mass% aqueous solution of anionic surfactant (NoigenXL-40, manufactured by first industrial pharmaceutical co., ltd) was changed to 1 part by mass of a 5 mass% aqueous solution of anionic surfactant (hiteonxl) NF-08, manufactured by first industrial pharmaceutical co., ltd), a low refractive index layer coating solution 10 containing a water-dispersible hydrophobic resin was prepared in the same manner as in example 1.

The refractive index of the film coated with the low refractive index layer coating liquid 10 containing the water-dispersible hydrophobic resin was 1.50.

Production of optical reflective film 11

In example 1 (preparation of optical reflection film 1), an optical reflection film 11 was prepared in the same manner as in example 1 except that the coating liquid for forming the low refractive index layer containing the water-dispersible hydrophobic resin was changed from the low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin to the low refractive index layer coating liquid 10 containing the water-dispersible hydrophobic resin prepared above, and the 19 th layer from the substrate side was used as the low refractive index layer containing the water-dispersible hydrophobic resin instead of the 11 th layer from the substrate side.

(example 12)

Preparation of coating liquid 11 for Low refractive index layer containing Water-dispersible hydrophobic resin

In example 1 (preparation of coating solution 1 for low refractive index layer containing dispersible hydrophobic resin), 19 parts by mass of a 10 mass% aqueous solution of acidic colloidal silica, 38 parts by mass of a 6 mass% aqueous solution of polyvinyl alcohol (JP-45, average degree of polymerization: 4500, degree of saponification: 99 mol%, manufactured by JAPAN VAM & POVAL), 3 parts by mass of a 6 mass% aqueous solution of water-dispersed urethane resin (ADEKA bonghher HUX-830, average particle size 100nm, manufactured by ADEKA corporation) to 18 parts by mass of a 6 mass% aqueous solution of water-dispersed acrylic resin (AE-120A, average particle size 55nm, manufactured by E-TEC), and 1 part by mass of a 5 mass% aqueous solution of anionic surfactant (NoigenXL-40, manufactured by first industrial pharmaceutical co., ltd.) to 1 part by mass of a 5 mass% aqueous solution of anionic surfactant (hitoen-tel) NF-08, manufactured by first industrial pharmaceutical co., ltd), a low refractive index layer coating liquid 11 containing a water-dispersible hydrophobic resin was prepared in the same manner as in example 1.

The refractive index of the film coated with the low refractive index layer coating liquid 11 containing the water-dispersible hydrophobic resin was 1.50.

Production of optical reflection film 12

In example 1 (preparation of optical reflection film 1), an optical reflection film 12 was prepared in the same manner as in example 1 except that the coating liquid for forming the low refractive index layer containing the water-dispersible hydrophobic resin was changed from the low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin to the low refractive index layer coating liquid 11 containing the water-dispersible hydrophobic resin prepared above, and the layer 19 from the substrate side was used as the low refractive index layer containing the water-dispersible hydrophobic resin.

(example 13)

Production of optical reflective film 13

In the above example 1 (preparation of optical reflection film 1), an optical reflection film 13 was prepared in the same manner as in example 1 except that the coating liquid for forming the low refractive index layer containing the water-dispersible hydrophobic resin was changed from the low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin to the low refractive index layer coating liquid 10 containing the water-dispersible hydrophobic resin, and the first layer 1 and the second layer 19 from the substrate side were low refractive index layers containing the water-dispersible hydrophobic resin.

(example 14)

Production of optical reflection film 14

In the above example 1 (preparation of optical reflection film 1), optical reflection film 14 was prepared in the same manner as in example 1 except that the coating liquid for forming the low refractive index layer containing the water-dispersible hydrophobic resin was changed from low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin to low refractive index layer coating liquid 11 containing the water-dispersible hydrophobic resin, and the 1 st and 19 th layers from the substrate side were low refractive index layers containing the water-dispersible hydrophobic resin.

(example 15)

Production of optical reflective film 15

In example 1 (preparation of optical reflection film 1), an optical reflection film 15 was prepared in the same manner as in example 1 except that the coating liquid for forming the low refractive index layer containing the water-dispersible hydrophobic resin was changed from the low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin to the low refractive index layer coating liquid 11 containing the water-dispersible hydrophobic resin, and all the low refractive index layers were changed to the low refractive index layers containing the water-dispersible hydrophobic resin.

Comparative example 1

Preparation of coating liquid 12 for Low refractive index layer containing Water-dispersible hydrophobic resin

In example 1 (preparation of low refractive index layer coating liquid 1 containing a dispersible hydrophobic resin), a low refractive index layer coating liquid 12 containing a water-dispersible hydrophobic resin was prepared in the same manner as in low refractive index layer coating liquid 1 containing a water-dispersible hydrophobic resin, except that 31 parts by mass of a 10 mass% aqueous solution of acidic colloidal silica, 38 parts by mass of a 6 mass% aqueous solution of polyvinyl alcohol, and 1 part by mass of a 6 mass% aqueous solution of a water-dispersible urethane resin were used.

The refractive index of the film coated with the low refractive index layer coating liquid 12 containing the water-dispersible hydrophobic resin was 1.50.

Production of optical reflection film 16

An optical reflection film 16 was produced in the same manner as in example 1, except that in example 1 (production of optical reflection film 1), the coating liquid for forming the low refractive index layer containing the water-dispersible hydrophobic resin was changed from low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin to low refractive index layer coating liquid 12 containing the water-dispersible hydrophobic resin.

Comparative example 2

Preparation of coating liquid 13 for Low refractive index layer containing Water-dispersible hydrophobic resin

In the above example 1 (preparation of low refractive index layer coating liquid 1 containing a dispersible hydrophobic resin), a low refractive index layer coating liquid 13 containing a water-dispersible hydrophobic resin was prepared in the same manner as in the low refractive index layer coating liquid 1 containing a water-dispersible hydrophobic resin, except that 38 parts by mass of a 6 mass% aqueous solution of polyvinyl alcohol (trade name: PVA-210, average degree of polymerization: 1000, degree of saponification: 88 mol%, manufactured by kohlrabi) was changed to 38 parts by mass of a water-soluble resin, and 31 parts by mass of a 10 mass% aqueous solution of acidic colloidal silica and 1 part by mass of a 6 mass% aqueous solution of a water-dispersible polyurethane resin were changed.

The refractive index of the film coated with the low refractive index layer coating liquid 13 containing the water-dispersible hydrophobic resin was 1.50.

Production of optical reflective film 17

In the above example 1 (preparation of optical reflection film 1), an optical reflection film 17 was prepared in the same manner as in example 1 except that the coating liquid for forming the low refractive index layer containing the water-dispersible hydrophobic resin was changed from the low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin to the low refractive index layer coating liquid 13 containing the water-dispersible hydrophobic resin, and the low refractive index layer containing the water-dispersible hydrophobic resin was formed from the 19 th layer on the substrate side instead of the 11 th layer on the substrate side.

Comparative example 3

Preparation of coating liquid for Low refractive index layer 14 containing Water-dispersible hydrophobic resin

In example 1 (preparation of low refractive index layer coating liquid 1 containing a dispersible hydrophobic resin), low refractive index layer coating liquid 14 containing a water-dispersible hydrophobic resin was prepared in the same manner as in low refractive index layer coating liquid 1 containing a water-dispersible hydrophobic resin, except that 10 parts by mass of an aqueous solution of acidic colloidal silica, 4 parts by mass of an aqueous solution of polyvinyl alcohol at 6% by mass, and 65 parts by mass of an aqueous solution of a water-dispersible urethane resin at 6% by mass.

The refractive index of the film coated with the low refractive index layer coating liquid 14 containing the water-dispersible hydrophobic resin was 1.50.

Production of optical reflection film 18

An optical reflection film 18 was produced in the same manner as in example 1, except that in example 1 (production of optical reflection film 1), the coating liquid for forming the low refractive index layer containing the water-dispersible hydrophobic resin was changed from low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin to low refractive index layer coating liquid 14 containing the water-dispersible hydrophobic resin.

Comparative example 4

Preparation of coating liquid 15 for Low refractive index layer containing Water-dispersible hydrophobic resin

In example 1 (preparation of low refractive index layer coating solution 1 containing a dispersible hydrophobic resin), a water-dispersible polyurethane resin 6 mass% aqueous solution was changed to a water-dispersible acrylic resin 6 mass% aqueous solution (AE-120A, average particle diameter 55nm, manufactured by JAPAN VAM & POVAL) 65 mass parts, using 9 mass parts of a 10 mass% aqueous solution of acidic colloidal silica, and 4 mass parts of a 6 mass% aqueous solution of polyvinyl alcohol (trade name: JM-23, average polymerization degree: 2300, saponification degree: 97 mol%, manufactured by JAPAN VAM & POVAL co.) and an anionic surfactant was not used, and a water-dispersible hydrophobic resin-containing low refractive index layer coating solution 15 was prepared in the same manner as in example 1.

The refractive index of the film coated with the low refractive index layer coating liquid 15 containing the water-dispersible hydrophobic resin was 1.50.

Production of optical reflective film 19

An optical reflection film 19 was produced in the same manner as in example 1, except that in example 1 (production of optical reflection film 1), the coating liquid for forming the low refractive index layer containing the water-dispersible hydrophobic resin was changed from low refractive index layer coating liquid 1 containing the water-dispersible hydrophobic resin to low refractive index layer coating liquid 15 containing the water-dispersible hydrophobic resin.

Evaluation

(measurement of haze)

The haze (%) of the optical reflective film samples produced in the examples and comparative examples was measured using a haze meter (NDH 2000 type manufactured by nippon electrochrome corporation), and the average value of 10 sheets of the optical reflective film samples was calculated. The haze value of the optical reflective film may be 2.5% or less, and preferably 1.5% or less.

(Observation of the Presence of coating film failure)

By visually observing the optical reflection film samples produced in the above examples and comparative examples, the total number (number/1000 m) of coating failures (splashes, aggregates) having a diameter of 2mm or more was measured²) The number of the samples was counted, and the average value of 10 samples of the optical reflective film was calculated and evaluated according to the following evaluation criteria.

O10/1000 m²In the following, the following description is given,

Δ > 10/1000 m²And 100 pieces/1000 m²In the following, the following description is given,

△ more than 100/1000 m²And 500 pieces/1000 m²In the following, the following description is given,

x: more than 500 pieces/1000 m²。

in practice, o, △, and △ can be used without any problem.

(weather resistance test)

The optical reflection films produced in the above examples and comparative examples were attached to blue glass having a thickness of 3mm via adhesive layers, respectively.

Specifically, the following adhesive layer-forming coating liquid was applied to the silicone release surface of the diaphragm NS23MA manufactured by packages co., ltd.using a notch wheel coater so that the dry film thickness became 10 μm, and dried at 90 ℃ for 1 minute to form an adhesive layer. The film having the dielectric multilayer film formed therein is laminated on the adhesive layer, and the adhesive layer is formed on the dielectric multilayer film.

Preparation of adhesive layer-forming coating liquid

A pressure-sensitive adhesive layer-forming coating liquid was prepared by adding 3 mass% of Coronatea L-55E (manufactured by Polyurethane, Japan) as a curing agent to COPONYL (registered trademark) N-6941M (manufactured by Nippon synthetic chemical Co., Ltd.) as a pressure-sensitive adhesive, further adding 5 mass% of Tinuvin477 (manufactured by BASF Japan) as an ultraviolet absorber, and diluting with ethyl acetate as a solvent so that the solid content became 10 mass%.

The sample was subjected to a xenon lamp weather meter (manufactured by SUGA testing machine Co., Ltd.; emission was very similar to that of the sample) at 50 ℃ and 70% RHLight of sunlight) to 180W/m²The exposure was repeated with a xenon light of intensity of 18 minutes of water jet and 22 minutes of drying. Thereafter, whether or not film cracking occurred in the film after exposure was visually confirmed every 10 hours, and the evaluation was performed according to the following evaluation criteria.

A: the film cracking is not generated, and the film cracking is avoided,

b: the film was slightly cracked to cause,

c: sufficient film cracking was produced by visual observation,

d: film cracking was clearly generated on the film as a whole.

The point at which C or more is obtained by the above evaluation is set as the crack occurrence time. The evaluation results are shown in table 1 below.

From the results of table 1 above, it is known that: optical reflective films of examples 1 to 15: the optical reflection film comprises a layer containing a water-dispersible hydrophobic resin, which contains a water-soluble resin and a water-dispersible hydrophobic resin, and contains 5-55% by mass of the water-dispersible hydrophobic resin relative to the mass of solid components in the layer containing the water-dispersible hydrophobic resin, and has excellent weather resistance as compared with the optical reflection films of comparative examples 1-4. In addition, it is known that: film failure is also reduced.

Further, in examples 5 to 8 using an anionic emulsion resin as a water-dispersible hydrophobic resin and containing an anionic surfactant, coating failures were further improved as compared with examples 1 to 4 and 9.

In addition, in the embodiments 11 to 15 using the anionic emulsion resin and the water-soluble resin with the average polymerization degree of 4000 to 6000 as the uppermost layer, the weather resistance is further improved, and the haze is also improved. In particular, it is known that: the effect of improving weather resistance is high in examples 13 and 14 in which the lowermost layer is also a layer containing a water-dispersible hydrophobic resin containing an anionic emulsion resin, or example 15 in which all of the low refractive index layers including the uppermost layer and the lowermost layer are water-dispersible hydrophobic resin containing an anionic emulsion resin.

It should be noted that the present application is based on Japanese patent application No. 2015-111712 filed on 1/6/2015, the disclosure of which is incorporated by reference in its entirety.

Claims (6)

1. An optical reflection film having a substrate and a dielectric multilayer film,

the dielectric multilayer film is disposed on one surface of the substrate and is formed by alternately laminating a low refractive index layer and a high refractive index layer,

at least 1 of the low refractive index layer and the high refractive index layer is a layer containing a water-dispersible hydrophobic resin, the layer containing the water-dispersible hydrophobic resin contains a water-soluble resin and 5 to 55 mass% of the water-dispersible hydrophobic resin relative to the total mass,

the layer containing a water-dispersible hydrophobic resin further contains an anionic surfactant, and the water-dispersible hydrophobic resin is an anionic emulsion resin.

2. The optical reflection film as claimed in claim 1,

in the dielectric multilayer film, the uppermost layer on the side opposite to the side contacting the substrate is the layer containing the water-dispersible hydrophobic resin.

3. The optical reflection film according to claim 1 or 2,

in the dielectric multilayer film, the lowermost layer in contact with the substrate is the layer containing the water-dispersible hydrophobic resin.

4. The optical reflection film according to claim 1 or 2,

the dielectric multilayer film has a low refractive index layer as the uppermost layer and a low refractive index layer as the lowermost layer, and the low refractive index layers are all the layers containing the water-dispersible hydrophobic resin.

5. The optical reflection film according to claim 1 or 2,

the average degree of polymerization of the water-soluble resin in the layer containing the water-dispersible hydrophobic resin is 4000 to 6000.

6. The method of manufacturing an optical reflection film according to claim 1, comprising:

a step of dissolving or dispersing a water-soluble resin, an anionic surfactant, and an anionic emulsion resin in an aqueous solvent to prepare a coating liquid;

a step of forming the layer containing the water-dispersible hydrophobic resin by applying the coating liquid.