WO2014188831A1 - Ultraviolet shielding film - Google Patents

Abstract

[Problem] The purpose of the present invention is to provide an ultraviolet shielding film which exhibits excellent ultraviolet shielding performance and maintains good light reflection characteristics even after being irradiated with sunlight or the like. [Solution] An ultraviolet shielding film which comprises a resin supporting body and an ultraviolet shielding multilayer part that contains at least one unit wherein a high refractive index layer and a low refractive index layer are laminated. The high refractive index layer and/or the low refractive index layer contains a water-soluble resin and metal oxide particles, and a resin layer that substantially contains no metal oxide particles and has a film thickness of 0.5 μm or more is provided between the resin supporting body and the ultraviolet shielding multilayer part.

Description

UV shielding film

The present invention relates to an ultraviolet shielding film.

Among the sun rays, ultraviolet rays contained in the region of a wavelength of about 10 to 400 nm have higher energy than visible rays and infrared rays having a long wavelength, and excite molecular bonds such as plastics and organic compounds or break them. It has energy of the same strength. For this reason, ultraviolet rays cause discoloration and discoloration of polymer materials and the like contained in various products, and cause a decrease in strength.

For this reason, in order to protect the member from ultraviolet rays, an ultraviolet shielding film in which a layer containing an organic ultraviolet absorber is disposed on the surface of the base material of the resin support has been conventionally used.

However, in a film containing an organic ultraviolet absorber, a phenomenon called “bleed out” occurs due to poor compatibility with the resin. Bleed-out refers to a phenomenon in which an ultraviolet absorber floats on the surface. When bleed-out occurs, the UV protection function is lost because the UV absorber flows out of the resin as well as poor appearance such as cloudiness and surface roughness of the film. For this reason, the organic ultraviolet absorber which can be used for the ultraviolet shielding film is often restricted by the compatibility with the resin.

Recently, it is well known that metal oxide particles are used as an alternative material for organic ultraviolet absorbers.

International Publication No. 00/27771 describes an ultraviolet shielding film having an alternately laminated layer of titania and silica in which titania and silica are laminated by sputtering. However, dry film forming methods such as sputtering have high manufacturing costs, are difficult to increase in area, and are limited to heat-resistant materials. Moreover, since the absorption wavelength of metal oxide particles is unique and cannot be controlled, it is difficult to produce a film that reflects a desired ultraviolet wavelength. For example, when the resin support is polyethylene terephthalate, it absorbs a short absorption wavelength of 360 nm or less, and the film turns yellow due to the absorption, but the absorption wavelength of titania is a short wavelength up to 340 nm. Since the ultraviolet absorbing ability is not sufficient, yellowing of the resin support proceeds.

Therefore, a method of producing an ultraviolet shielding part by a coating method using a resin has come to be used. For example, in International Publication No. 2011/062836, a layer that reflects ultraviolet rays is formed by alternately combining two types of polymer layers having different refractive indexes. According to this, the ultraviolet shielding region can be easily set by controlling the film thickness and the number of layers of the polymer layer, and the area can be increased by stretching the film. This production method is characterized by heating and stretching near the glass transition point of the polymer.

However, it was found that in the film described in International Publication No. 2011/062836, the oxidative deterioration of the resin support was promoted by light irradiation, the optical spectrum of the film was changed, and the maximum reflectance was lowered. In addition, in the film described in International Publication No. 2011/062836, the adhesiveness between the resin support and the polymer layer in the shielding film may be reduced due to light irradiation.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ultraviolet shielding film that has excellent ultraviolet shielding properties and maintains good light reflection characteristics even when irradiated with sunlight or the like. Is to provide. Another object of the present invention is to provide an ultraviolet shielding film having high adhesion between the resin support and the ultraviolet shielding portion.

In order to achieve at least one of the above-described objects of the present invention, an ultraviolet shielding film reflecting one aspect of the present invention includes: a resin support, and a laminate of a high refractive index layer and a low refractive index layer An ultraviolet shielding film having an ultraviolet shielding laminated portion including at least one unit, wherein at least one of the high refractive index layer and the low refractive index layer contains a water-soluble resin and metal oxide particles, and the resin support And an ultraviolet shielding film in which a resin layer substantially not containing metal oxide particles and having a film thickness of 0.5 μm or more is provided between the ultraviolet shielding laminate.

It is a section schematic diagram of one embodiment of an ultraviolet shielding film. In FIG. 1, 1 is an ultraviolet shielding film, 2 is a substrate (resin support), 3 is a resin layer, and 4 is an ultraviolet shielding laminate.

One embodiment of the present invention is an ultraviolet shielding film having an ultraviolet shielding laminated portion including at least one unit obtained by laminating a resin support and a high refractive index layer and a low refractive index layer, the high refractive index layer And at least one layer of the low refractive index layer contains a water-soluble resin and metal oxide particles, and does not substantially contain metal oxide particles and has a film thickness between the resin support and the ultraviolet shielding laminate. It is an ultraviolet shielding film provided with a resin layer of 0.5 μm or more.

As described above, the ultraviolet shielding film stretched by alternately combining two kinds of polymer layers having different refractive indexes as described in International Publication No. 2011/062836 has remarkably optical characteristics when irradiated for a long time. The inventor has found that this is reduced. The film described in WO 2011/062836 is heated and stretched near the glass transition point of the polymer to produce a film. Radicals are generated to heat the polymer to near the glass transition temperature. Such radicals are considered to be the cause of promoting the oxidative degradation of the polymer in the ultraviolet shielding laminate. And it is thought that deterioration of the polymer itself resulting from a radical is accelerated more by light irradiation, and a ultraviolet-ray shielding characteristic is reduced remarkably. And by such a fall of an ultraviolet-ray shielding characteristic, in the film as described in international publication 2011/062836, the lower layer resin support body may turn yellow by oxidation degradation etc., and the transmittance | permeability in visible light may fall. all right. Furthermore, the adhesiveness between the resin support and the polymer layer in the shielding film may be reduced by light irradiation.

For this reason, the present inventor has searched for a method that does not require heating of the ultraviolet shielding laminate in the production of the ultraviolet shielding film. Attention was paid to a method for producing an ultraviolet shielding film by coating. As a method for forming an optical shielding film by coating, for example, International Publication No. 2012/014607 discloses a near-infrared reflective film obtained by mixing metal oxide particles with a water-soluble resin and applying aqueous coating to a substrate. Yes. According to this production method, heating at a high temperature is not required, and thus it is considered that radicals generated by stretching heating have a very small effect on film deterioration. Furthermore, since a metal oxide particle having a low refractive index and a metal oxide particle having a high refractive index can be appropriately selected and dispersed in an aqueous solution, a film having a large refractive index difference can be formed in a large area.

Next, the present inventor examined the UV shielding film obtained by coating from the viewpoint of weather resistance, which is the above problem. Specifically, a water-soluble resin containing low-refractive-index metal oxide particles and high-refractive-index metal oxide particles is alternately applied to the surface of the polyester film, and then exposed to ultraviolet rays using a xenon lamp similar to sunlight. went. As a result, the polyester film turned yellow when irradiated with ultraviolet rays corresponding to 10 years of Phoenix, Arizona, USA. When the polymer layer containing metal oxide particles was analyzed in order to search for the cause of yellowing, the ultraviolet rays that could not be reflected hit the metal oxide particles in the film, and the oxygen atoms of the metal oxide particles were desorbed. It has been found by examination of the present inventors that the oxidative deterioration of the polyester film is promoted.

That is, it has been found that there is a problem that the metal oxide in the ultraviolet shielding part generates oxygen by receiving ultraviolet rays, and the generated oxygen attacks the resin support and deteriorates.

In order to prevent such a problem, in the present invention, a resin layer that is substantially free of metal oxide particles and has a certain thickness is provided between the ultraviolet shielding laminated portion and the resin support.

Therefore, according to the configuration of the present invention, the light reflectivity of a desired wavelength is excellent, and good light reflection characteristics are maintained because the oxidative deterioration of the resin support due to irradiation with sunlight or the like is suppressed. An ultraviolet shielding film can be provided. Moreover, according to the structure of this invention, the ultraviolet shielding film with high adhesiveness of a base material and an ultraviolet shielding part can be provided. In addition, since water-based coating is possible, it can be applied to simultaneous multi-layer coating with excellent environmental conservation during production and high productivity.

In this specification, the term “ultraviolet shielding film” means that the amount of ultraviolet light on the opposite side of the light incident on the film is reduced by the reflection or reflection and absorption of the ultraviolet shielding film with respect to the amount of ultraviolet light of the incident light. Means film. The “ultraviolet shielding laminate” refers to a laminate that reflects or reflects ultraviolet rays. In addition, this invention is not limited to the said guess.

Hereinafter, the best mode for carrying out the present invention will be described in detail.

FIG. 1 is a schematic cross-sectional view of an embodiment of an ultraviolet shielding film. The ultraviolet shielding film 1 in FIG. 1 includes a base material 2 that is a resin support, a resin layer 3, and an ultraviolet shielding laminated portion 4 in this order. The ultraviolet shielding laminated portion 4 is disposed on a surface on which light is incident.

In the form of FIG. 1, the resin layer 3, the ultraviolet shielding laminate 4, and the substrate 2 are disposed adjacent to each other in this order, but between the substrate 2 and the resin layer 3, the resin layer 3 and the ultraviolet shielding laminate. Another layer may be interposed between the portions 4.

[Resin layer]
The resin layer is substantially free of metal oxide particles. Here, “substantially free” includes the case where the metal oxide particles are contained by contamination. Specifically, in the present invention, the phrase “substantially free of metal oxide particles” means containing 0 to 1% by mass of metal oxide particles with respect to 100% by mass of the resin layer solid content, preferably 0 -0.5% by mass, more preferably 0-0.1% by mass. In addition, as a metal oxide particle here, the metal oxide particle described in the column of the following ultraviolet-ray shielding laminated part is mentioned.

The thickness of the resin layer is 0.5 μm or more. When the thickness of the resin layer is 0.5 μm or more, it is possible to physically block the influence of the metal oxide particles contained in the ultraviolet shielding laminated portion on the lower layer resin support, and the oxidation of the resin support Deterioration can be suppressed. For this reason, even after irradiation with light or the like, good light reflection characteristics are maintained, and adhesion between the substrate and the ultraviolet shielding part is also maintained high.

Further, when the resin layer is 0.5 μm or more, a certain strength can be imparted. The imparting of such strength is important for a film that requires a thin film of each refractive index layer in terms of optical characteristics such as an ultraviolet shielding film. That is, when the thickness of the resin layer is less than 0.5 μm, when the produced film is dried and the film is cured, the film may be curled with the curing. The occurrence of such curling becomes a serious problem in proportion to the reduction in the thickness of the refractive index layer. Then, curling makes it difficult to bond the film to the substrate, and the cured film is hard and brittle, so that cracks may occur, which may be a problem. Under high-temperature and high-humidity conditions, it is considered that the cracks generated further progress due to the expansion of the base material and the like, which may affect the optical characteristics.

The upper limit of the thickness of the resin layer is not particularly limited, but it is preferably 5 μm or less in consideration of the thickness and transparency of the entire film. The thickness of the resin layer is more preferably 0.5 to 1 μm. Further, the thickness of the resin layer is preferably 3 to 20 times the average thickness of each refractive index layer constituting the ultraviolet shielding laminated portion, since the effects of the present invention can be further obtained. It is more preferable that Here, the average thickness of each refractive index layer means the average thickness of all refractive index layers of the ultraviolet shielding laminated portion located on the side of the resin support on which the resin layer is provided. Therefore, when the refractive index layer is formed on the side opposite to the side where the resin layer is provided and the resin support (when the refractive index layer is formed on both sides of the resin support), the refractive index on the opposite side The layer is not included in the refractive index layer when considering the average thickness.

The resin layer contains a resin. Here, the resin used for the resin layer is preferably a polymer that does not have an aromatic ring in the main chain because it is resistant to photodegradation, and more preferably a resin composed of monomer components that do not have an aromatic ring. is there. In the present invention, this is a non-aromatic resin. Specific examples of the resin used as the resin layer include water-soluble resins, silicone resins, acrylic resins, olefin resins, vinyl chloride resins, acrylic / urethane resins, and fluorine-containing polymers.

In the present invention, the ultraviolet shielding laminated portion contains a water-soluble resin and can be applied in water, and when used as an adjacent layer, the adhesion with the ultraviolet shielding laminated portion is improved. It is preferable to include a water-soluble resin. In addition, since the solvent of the water-soluble polymer is water, there is an advantage that it does not cause corrosion, dissolution or penetration into the lower layer resin support. Therefore, when the water-soluble polymer is used, the deterioration of the resin support can be prevented for a longer period than when other resins are used. Furthermore, the water-soluble resin is preferable because it has high flexibility and thus improves the durability of the film when bent.

Examples of water-soluble resins include polyvinyl alcohols, polyvinyl pyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymers, potassium acrylate-acrylonitrile copolymers, vinyl acetate-acrylic ester copolymers, or Acrylic resins such as acrylic acid-acrylic acid ester copolymer, styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-acrylic acid ester copolymer, styrene-α-methylstyrene- Styrene acrylic resin such as acrylic acid copolymer or styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymer, styrene-sodium styrenesulfonate copolymer, styrene-2-hydroxyethyl acrylate copolymer , Styrene-2 -Hydroxyethyl acrylate-potassium styrene sulfonate copolymer, styrene-maleic acid copolymer, styrene-maleic anhydride copolymer, vinyl naphthalene-acrylic acid copolymer, vinyl naphthalene-maleic acid copolymer, vinyl acetate -Synthetic water-soluble resins such as maleic acid ester copolymers, vinyl acetate-crotonic acid copolymers, vinyl acetate-based copolymers such as vinyl acetate-acrylic acid copolymers and their salts; gelatin, thickening polysaccharides Natural water-soluble resins such as Among these, particularly preferred examples include polyvinyl alcohol, polyvinylpyrrolidones and copolymers containing them, gelatin, thickening polysaccharides (particularly celluloses) from the viewpoint of handling during production and film flexibility. Among these, polyvinyl alcohol is more preferable from the viewpoint of optical properties. These water-soluble resins may be used alone or in combination of two or more.

The polyvinyl alcohol preferably used in the present invention includes modified polyvinyl alcohol in addition to ordinary polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate. Examples of the modified polyvinyl alcohol include cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, nonion-modified polyvinyl alcohol, and vinyl alcohol polymers.

The polyvinyl alcohol obtained by hydrolyzing vinyl acetate preferably has an average degree of polymerization of 1,000 or more, and particularly preferably has an average degree of polymerization of 1,500 to 5,000. The degree of saponification is preferably 70 to 100 mol%, particularly preferably 80 to 99.5 mol%.

Here, the degree of polymerization refers to the viscosity average degree of polymerization, and is measured according to JIS-K6726 (1994). After the PVA is completely re-saponified and purified, the intrinsic viscosity [η] measured in water at 30 ° C. It can be obtained from (dl / g) by the following equation.

Examples of the cation-modified polyvinyl alcohol have primary to tertiary amino groups and quaternary ammonium groups in the main chain or side chain of the polyvinyl alcohol as described in JP-A-61-10383. Polyvinyl alcohol, which is obtained by saponifying a copolymer of an ethylenically unsaturated monomer having a cationic group and vinyl acetate.

Examples of the ethylenically unsaturated monomer having a cationic group include trimethyl- (2-acrylamido-2,2-dimethylethyl) ammonium chloride and trimethyl- (3-acrylamido-3,3-dimethylpropyl) ammonium chloride. N-vinylimidazole, N-vinyl-2-methylimidazole, N- (3-dimethylaminopropyl) methacrylamide, hydroxylethyltrimethylammonium chloride, trimethyl- (2-methacrylamidopropyl) ammonium chloride, N- (1, And 1-dimethyl-3-dimethylaminopropyl) acrylamide. The ratio of the cation-modified group-containing monomer in the cation-modified polyvinyl alcohol is 0.1 to 10 mol%, preferably 0.2 to 5 mol%, relative to vinyl acetate.

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

Nonionic modified polyvinyl alcohols include, for example, polyvinyl alcohol derivatives obtained by adding a polyalkylene oxide group to a part of vinyl alcohol as described in JP-A-7-9758, and described in JP-A-8-25795. Block copolymer of vinyl compound having hydrophobic group and vinyl alcohol, silanol modified polyvinyl alcohol having silanol group, reactive group modified polyvinyl alcohol having reactive group such as acetoacetyl group, carbonyl group, carboxyl group Etc. Examples of the vinyl alcohol polymer include Exeval (trade name: manufactured by Kuraray Co., Ltd.) and Nichigo G polymer (trade name: manufactured by Nippon Synthetic Chemical Industry Co., Ltd.). Polyvinyl alcohol can be used in combination of two or more, such as the degree of polymerization and the type of modification.

As the gelatin, in addition to lime-processed gelatin, acid-processed gelatin may be used, and gelatin hydrolyzate and gelatin enzyme-decomposed product can also be used.

Examples of thickening polysaccharides include natural simple polysaccharides, natural complex polysaccharides, synthetic simple polysaccharides and synthetic complex polysaccharides that are generally known. Reference can be made to the encyclopedia (2nd edition), Tokyo Kagaku Doujin Publishing, “Food Industry”, Vol. 31 (1988), p. 21.

The thickening polysaccharide referred to in the present invention is a polymer of saccharides and has many hydrogen bonding groups in the molecule, and the viscosity at low temperature and the viscosity at high temperature due to the difference in hydrogen bonding force between molecules depending on the temperature. It is a polysaccharide with a large difference in characteristics, and when adding metal oxide fine particles, it causes a viscosity increase that seems to be due to hydrogen bonding with the metal oxide fine particles at a low temperature. It is a polysaccharide that causes a viscosity increase at 40 ° C. of 1.0 mPa · s or more by addition, preferably 5.0 mPa · s or more, more preferably 10.0 mPa · s or more. Polysaccharides.

Examples of the thickening polysaccharide include β1-4 glucan (eg, carboxymethylcellulose, carboxyethylcellulose, etc.), galactan (eg, agarose, agaropectin, etc.), galactomannoglycan (eg, locust bean gum, guaran, etc.), xylo Glucan (eg, tamarind gum, etc.), glucomannoglycan (eg, salmon mannan, wood-derived glucomannan, xanthan gum, etc.), galactoglucomannoglycan (eg, softwood-derived glycan), arabinogalactoglycan (eg, soybean) Glycans derived from microorganisms, glycans derived from microorganisms, etc.), glucoraminoglycans (eg, gellan gum, etc.), glycosaminoglycans (eg, hyaluronic acid, keratan sulfate, etc.), alginic acid and alginates, agar, κ-carrageenan, Examples thereof include natural polymer polysaccharides derived from red algae such as λ-carrageenan, ι-carrageenan, and far cerulean.

The weight average molecular weight of the water-soluble resin is preferably 1,000 or more and 200,000 or less. Furthermore, 3,000 or more and 40,000 or less are more preferable. In this specification, the value measured on the following measurement conditions using gel permeation chromatography (GPC) is employ | adopted for a weight average molecular weight.

Solvent: 0.2M
NaNOH ₃ , NaH ₂ P0 ₄ , pH 7
Column: Combination of Shodex Column Ohpak SB-802.5 HQ, 8 × 300 mm and Shodex Column Ohpak SB-805 HQ, 8 × 300 mm Column temperature: 45 ° C.
Sample concentration: 0.1% by mass
Detector: RID-10A (manufactured by Shimadzu Corporation)
Pump: LC-20AD (manufactured by Shimadzu Corporation)
Flow rate: 1 ml / min
Calibration curve: Standard P-82 standard curve for Shodex standard GFC (aqueous GPC) column Use of calibration curve with pullulan standard substance In the present invention, a curing agent may be used to cure the water-soluble resin as a binder.

The curing agent is not particularly limited as long as it causes a curing reaction with a water-soluble resin.

When the water-soluble resin is polyvinyl alcohol, the curing agent that can be used is not particularly limited as long as it causes a curing reaction with polyvinyl alcohol, but a group consisting of boric acid, borate, and borax. Is preferably selected from. Known compounds other than boric acid, borate, and borax can be used, and generally compounds having a group capable of reacting with polyvinyl alcohol or compounds that promote the reaction between different groups possessed by polyvinyl alcohol These are appropriately selected and used. Specific examples of the curing agent include, for example, epoxy curing agents (diglycidyl ethyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-diglycidyl cyclohexane, N, N-diglycidyl- 4-glycidyloxyaniline, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, etc.), aldehyde curing agents (formaldehyde, glioxal, etc.), active halogen curing agents (2,4-dichloro-4-hydroxy-1,3,5) , -S-triazine, etc.), active vinyl compounds (1,3,5-trisacryloyl-hexahydro-s-triazine, bisvinylsulfonylmethyl ether, etc.), aluminum alum and the like.

Boric acid or borate refers to oxyacids and salts thereof having a boron atom as a central atom, and specifically, orthoboric acid, diboric acid, metaboric acid, tetraboric acid, pentaboric acid, and octaborate. Boric acid and their salts.

Borax is a mineral represented by Na ₂ B ₄ O ₅ (OH) ₄ .8H ₂ O (decahydrate of sodium tetraborate Na ₂ B ₄ O ₇ ).

Boric acid having a boron atom, borate, and borax as a curing agent may be used alone or as a mixture of two or more. An aqueous solution of boric acid or a mixed aqueous solution of boric acid and borax is preferred. The aqueous solutions of boric acid and borax can be added only as relatively dilute aqueous solutions, respectively, but by mixing them both can be made into a concentrated aqueous solution and the coating solution can be concentrated. Further, the pH of the aqueous solution to be added can be controlled relatively freely.

In the present invention, it is preferable to use boric acid and a salt thereof and / or borax in order to obtain the effects of the present invention. When boric acid and its salts and / or borax are used, preferable ultraviolet shielding properties can be achieved more. In particular, when a multilayer coating of a high refractive index layer and a low refractive index layer is applied with a coater, the film surface temperature of the coating film is once cooled to about 15 ° C., and then the set surface coating process is used to dry the film surface. Can express an effect more preferably.

The total amount of the curing agent used is preferably 1 to 600 mg, more preferably 100 to 500 mg, per gram of polyvinyl alcohol resin.

When the water-soluble resin is gelatin, for example, organic hardeners such as vinyl sulfone compounds, urea-formalin condensates, melanin-formalin condensates, epoxy compounds, aziridine compounds, active olefins, isocyanate compounds, Examples thereof include inorganic polyvalent metal salts such as chromium, aluminum and zirconium.

The resin used for the resin layer is not limited to the above water-soluble resin, and may be other polymers. The resin used for the resin layer is, for example, a silicone resin, an acrylic resin, an olefin resin (particularly, a cycloolefin resin), a vinyl chloride resin, an acrylic / urethane resin from the viewpoint of preventing yellowing due to ultraviolet rays. And fluorine-containing polymers. Among these, a silicone resin having a siloxane bond or an acrylic copolymer obtained by copolymerizing at least two or more acrylic monomers can be suitably used as a material particularly excellent in weather resistance.

Silicone resin hydrolyzes a compound represented by R _X Si (OR ′) _4-X , where R and R ′ are organic groups such as methyl and ethyl groups, and X is an integer of 0 to 4. -It is preferable that it is obtained by polycondensation.

As the silicone resin, for example, commercially available products such as trimethoxysilane (Kanto Chemical), Solgard NP-730 (Nihon Dacro Shamrock), Tosgard 510 (Toshiba Silicone), KP-64 (Shin-Etsu Chemical Co., Ltd.) Good.

Specific examples of the acrylic resin include, for example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, cyclohexyl methacrylate. 1 or two or more monomers selected from monomers having no functional group in the side chain such as alkyl (meth) acrylate such as 2-ethylhexyl methacrylate (hereinafter referred to as non-functional monomer), In addition, side chains of one or more monomers selected from monomers such as 2-hydroxyethyl methacrylate, glycidyl methacrylate, acrylic acid, methacrylic acid, and itaconic acid. In addition, one or more monomers having a functional group such as OH or COOH (hereinafter referred to as functional monomers) may be combined in some cases, such as solution polymerization method, suspension polymerization method, emulsion polymerization method, bulk polymerization method, etc. Examples thereof include acrylic copolymers having a weight average molecular weight of 40,000 to 1,000,000, preferably 100,000 to 400,000, obtained by copolymerization by a polymerization method. Among them, non-functional monomers that give a relatively low Tg polymer such as ethyl acrylate, methyl acrylate, 2-ethylhexyl methacrylate, etc., and polymers having a relatively high Tg such as methyl methacrylate, isobutyl methacrylate, cyclohexyl methacrylate, etc. Most preferred is an acrylic polymer containing 10 to 50% by mass of the non-functional monomer to be provided and 0 to 10% by mass of a functional monomer such as 2-hydroxyethyl methacrylate, acrylic acid or itaconic acid.

The cycloolefin resin is a polymer resin containing an alicyclic structure. A preferred cycloolefin resin is a resin obtained by polymerizing or copolymerizing a cyclic olefin. Examples of the cyclic olefin include norbornene, dicyclopentadiene, tetracyclododecene, ethyltetracyclododecene, ethylidenetetracyclododecene, tetracyclo [7.4.0.110, 13.02,7] trideca-2,4, Unsaturated hydrocarbons of polycyclic structures such as 6,11-tetraene and derivatives thereof, cyclobutene, cyclopentene, cyclohexene, 3,4-dimethylcyclopentene, 3-methylcyclohexene, 2- (2-methylbutyl) -1-cyclohexene, cyclo Examples thereof include monocyclic unsaturated hydrocarbons such as octene, 3a, 5,6,7a-tetrahydro-4,7-methano-1H-indene, cycloheptene, cyclopentadiene, cyclohexadiene, and derivatives thereof. Preferred cycloolefin resins may be those obtained by addition copolymerization of monomers other than cyclic olefins. Examples of addition copolymerizable monomers include ethylene such as ethylene, propylene, 1-butene and 1-pentene or α-olefin, 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl- And dienes such as 1,4-hexadiene and 1,7-octadiene.

Examples of cycloolefin resins include the following norbornene resins. The norbornene-based resin preferably has a norbornene skeleton as a repeating unit. Specific examples thereof include, for example, JP-A Nos. 2003-139950, 2003-14901, and 2003-161832. JP-A-2003-195268, JP-A-2003-212588, JP-A-2003-211589, JP-A-2003-268187, JP-A-2004-133209, JP-A-2004-3091979, JP 2005-121813, JP 2005-164632, JP 2006-72309, JP 2006-178191, JP 2006-215333, JP 2006-268065, JP 2006. -299199 etc. Including without being limited thereto. Moreover, these may be used individually by 1 type and may use 2 or more types together. Specifically, ZEONEX, ZEONOR manufactured by Nippon Zeon Co., Ltd., Arton manufactured by JSR Corporation, APPEL manufactured by Mitsui Chemicals, Inc. (APL8008T, APL6509T, APL6013T, APL5014DP, APL6015T) and the like are preferably used.

Examples of vinyl chloride resins include vinyl chloride homopolymer (vinyl chloride homopolymer), a copolymer of a monomer having an unsaturated bond copolymerizable with vinyl chloride monomer and vinyl chloride monomer, and vinyl chloride monomer in the polymer. Examples thereof include graft copolymers obtained by graft copolymerization, and (co) polymers composed of chlorinated vinyl chloride monomer units. These may be used alone or in combination of two or more. Chlorination of the vinyl chloride monomer unit may be performed before polymerization or may be performed after polymerization. When the vinyl chloride copolymer is used, the content of the monomer units other than the vinyl chloride monomer unit is within a range that does not impair the original performance, and the unit derived from the vinyl chloride monomer is 50% by mass or more and 60% by mass. % Or more or 70% by mass or more, for example, about 50 to 99% by mass, preferably 60 to 99% by mass or 70 to 99% by mass (in the mass calculation here, the vinyl chloride resin contains a plasticizer. And other polymers blended with the copolymer resin). Examples of monomers having an unsaturated bond copolymerizable with vinyl chloride monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and n-butyl (meth) ) Acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, neopentyl (meth) acrylate, cyclopentyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate , N-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate , Tridecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, behenyl (meth) acrylate, phenyl (meth) acrylate, toluyl (meth) acrylate, xylyl (meth) acrylate, benzyl (meth) acrylate (Meth) acrylic acid such as 2-ethoxyethyl (meth) acrylate, 2-butoxy (meth) acrylate, 2-phenoxy (meth) acrylate, 3-methoxypropyl (meth) acrylate, 3-ethoxypropyl (meth) acrylate Derivatives; α-olefins such as ethylene, propylene and butylene; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as butyl vinyl ether and cetyl vinyl ether; styrene, α-methyls Aromatic vinyls such as len; vinyl vinyl halides such as vinylidene chloride and vinylidene fluoride; N-substituted maleimides such as N-phenylmaleimide and N-cyclohexylmaleimide, (meth) acrylic acid, maleic anhydride, acrylonitrile, etc. Is mentioned. These may be used alone or in combination of two or more.

Examples of the acrylic / urethane resin include acrylic / urethane copolymer resins described in the column of the ultraviolet absorber-containing layer described later.

Examples of the fluorine-containing polymer include the fluorine-containing polymers described in the column of the water-soluble resin described later.

In addition, the undercoat layer described in the column of the resin support described later, the adhesive layer described later, the ultraviolet absorber-containing layer, and the like are also resin layers containing a resin and have a thickness of 0.5 μm or more. In the case of being disposed between the reflective laminated portion, the resin layer of the present invention can be obtained.

Further, when there are two or more layers containing a resin, at least one layer does not substantially contain metal oxide particles between the resin support and the ultraviolet shielding laminate, and the film thickness is 0.00. What is necessary is just 5 micrometers or more. A plurality of resin layers may be present, and as a form in which two or more resin layers exist, a resin support, an ultraviolet absorber-containing adhesive layer (resin layer), a water-soluble resin-containing layer (resin layer), an ultraviolet shielding An ultraviolet shielding film in which the laminated portions are laminated in this order is exemplified. Moreover, in this specification, a resin layer does not indicate the whole formed from a plurality of layers, but means each single layer composed of a resin.

The content of the resin contained in the resin layer is preferably 50 to 100% by mass, and preferably 80 to 100% by mass with respect to the solid content of the resin layer. If it is 50 mass% or more, layer formation is possible.

The resin layer preferably contains a surfactant from the viewpoint of applicability.

An anionic surfactant, a nonionic surfactant, an amphoteric surfactant, and the like can be used as the surfactant used for adjusting the surface tension during coating, but an anionic surfactant is more preferable. Preferable compounds include those containing a hydrophobic group having 8 to 30 carbon atoms and a sulfonic acid group or a salt thereof in one molecule.

Anionic surfactants include alkyl benzene sulfonate, alkyl naphthalene sulfonate, alkane or olefin sulfonate, alkyl sulfate ester salt, polyoxyethylene alkyl or alkyl aryl ether sulfate ester, alkyl phosphate, alkyl diphenyl ether A surfactant selected from the group consisting of disulfonates, ether carboxylates, alkylsulfosuccinates, α-sulfo fatty acid esters and fatty acid salts, condensates of higher fatty acids with amino acids, naphthenates, etc. may be used. it can. Anionic surfactants preferably used are alkylbenzene sulfonates (especially those of linear alkyls), alkanes or olefin sulfonates (especially secondary alkane sulfonates, α-olefin sulfonates), alkyl sulfates Salts, polyoxyethylene alkyl or alkylaryl ether sulfates (especially polyoxyethylene alkyl ether sulfates), alkyl phosphates (especially monoalkyl type), ether carboxylates, alkyl sulfosuccinates, α-sulfo fatty acid esters and A surfactant selected from the group consisting of fatty acid salts, and alkylsulfosuccinate is particularly preferable.

The content of the surfactant in each resin layer is preferably 0.001 to 0.5% by mass, preferably 0.005 to 0.3% by mass, as the solid content of the refractive index layer is 100% by mass. Is more preferable.

In addition, various additives described in the column of the ultraviolet shielding laminate below may be added to the resin layer. Furthermore, the resin layer may contain an ultraviolet absorber in order to more effectively protect the member in the lower layer of the film from ultraviolet rays and from the deterioration of the resin support. As an ultraviolet absorber, the ultraviolet absorber as described in the column of the following ultraviolet absorber content layer is mentioned. The content of the resin layer of the ultraviolet absorber is preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass.

(A form in which the resin layer is formed adjacent to the ultraviolet shielding laminate)
The arrangement of the resin layer in the film is not particularly limited as long as it is between the resin support and the ultraviolet shielding laminate, but the resin layer may be formed adjacent to the ultraviolet shielding laminate. preferable. By setting it as such a form, the influence on the resin support of the oxygen generation by the ultraviolet-ray from the metal oxide which exists in an ultraviolet-ray shielding laminated part can be suppressed effectively. Further, it is preferable to form the resin layer adjacent to the ultraviolet shielding laminated portion because the resin layer can be formed together with the ultraviolet shielding laminated portion by simultaneous multilayer coating, and the production efficiency is improved.

When the resin layer is adjacent to the ultraviolet shielding laminate, the resin layer preferably has a refractive index different from that of the refractive index layer in contact with the resin layer constituting the ultraviolet shielding laminate. The refractive index layer in contact with the resin layer is preferably a high refractive index layer, and the refractive index of the resin layer is preferably lower than the refractive index of the high refractive index layer. Such a configuration is preferable because the adhesion between the resin layer and the resin support is improved. From the viewpoint of suppressing aggregation of metal oxide particles contained in the refractive index layer in contact with the resin layer, it is more preferable to control the configuration of the water-soluble resin applied to the refractive index layer in contact with the resin layer. In particular, when a silica-attached titanium dioxide sol that easily aggregates metal oxide particles is used, the structure of the water-soluble resin applied to the refractive index layer in contact with the resin layer may be controlled in order to suppress aggregation. preferable. Specifically, in one embodiment, the refractive index layer in contact with the resin layer preferably includes at least two types of water-soluble resins. By using at least two water-soluble resins in combination, the metal oxide particles can be stabilized and aggregation and the like can be suppressed, and properties such as cracks and haze can be improved.

Preferably, the refractive index layer in contact with the resin layer preferably contains water-soluble resins having different average polymerization degrees (water-soluble resins having a low average polymerization degree and water-soluble resins having a high average polymerization degree).

The mixing mass ratio of the water-soluble resin having a low average degree of polymerization and the water-soluble resin having a high average degree of polymerization is not particularly limited, but the water-soluble resin having a low average degree of polymerization: a water-soluble resin having a high average degree of polymerization = 1: 5 to 20 is preferable.

The average degree of polymerization of one of the at least two water-soluble resins is preferably 100 to 700, more preferably 200 to 500. The water-soluble resin is preferably polyvinyl alcohol from the viewpoint of adsorptivity. Furthermore, polyvinyl alcohol having an average degree of polymerization of 100 to 700 preferably has a saponification degree of 95 mol% or more.

The other water-soluble resin of at least two types of water-soluble resins preferably has an average degree of polymerization of 1500 to 5000, and more preferably 1500 to 4000. The water-soluble resin is preferably polyvinyl alcohol, and is preferably unmodified polyvinyl alcohol from the viewpoint of applicability. Further, the polyvinyl alcohol preferably has a saponification degree of 85 to 99.5 mol%.

[Ultraviolet shielding laminate]
The ultraviolet shielding laminated portion has at least one unit in which a low refractive index layer and a high refractive index layer are laminated. A preferred form of the ultraviolet shielding laminated portion is an alternate laminated body in which low refractive index layers and high refractive index layers are alternately laminated. That is, the preferable ultraviolet shielding part of the present invention can be said to be an ultraviolet reflecting part using the refractive index difference of each refractive index layer. Needless to say, even the ultraviolet reflecting part using the difference in refractive index may have ultraviolet absorbing ability depending on the selection of the metal oxide.

In this specification, the terms “high refractive index layer” and “low refractive index layer” refer to a refractive index layer having a higher refractive index when comparing the refractive index difference between two adjacent layers. It means that the lower refractive index layer is a low refractive index layer. Therefore, the terms “high refractive index layer” and “low refractive index layer” mean that, in each refractive index layer constituting the ultraviolet shielding laminated part, when each refractive index layer is focused on two adjacent refractive index layers, All forms other than those having the same refractive index are included.

The thickness of the ultraviolet shielding laminated portion is preferably 10 μm or less, more preferably 9 μm or less from the viewpoint of flexibility. Such thinning of the film can increase the difference in refractive index between the refractive index layers when each refractive index layer contains water-soluble resin and metal oxide particles. It is easy to realize in a form containing resin and metal oxide particles. Further, the lower limit of the thickness of the ultraviolet shielding laminated portion is not particularly limited, but is usually 1 μm or more from the viewpoint of ensuring reflection characteristics. The thickness of the ultraviolet shielding laminate is preferably 1 to 3 μm.

(Water-soluble resin)
In the present invention, it is sufficient that at least one of the high refractive index layer and the low refractive index layer contains a water-soluble resin, but since production by simultaneous multilayer coating is possible, the high refractive index layer and the low refractive index layer It is preferable that both contain water-soluble resin. Moreover, the hardening | curing agent described in the column of the said resin layer can be used similarly, and a suitable hardening | curing agent is also the same.

Examples of the water-soluble resin include the water-soluble resins described in the column of the resin layer. Of these, polyvinyl alcohol is preferably used because of its good optical reflection characteristics.

Further, when both the high refractive index layer and the low refractive index layer contain polyvinyl alcohol, the average saponification degree of polyvinyl alcohol contained in the high refractive index layer and the average saponification degree of polyvinyl alcohol contained in the low refractive index layer. And are preferably different.

Water-soluble coating such as polyvinyl alcohol is possible. In the case of aqueous coating, each coating liquid that can form a high-refractive index layer and a low-refractive index layer is usually used. Manufactured by stacking. However, the coating film obtained by multilayer coating tends to cause mixing between adjacent layers and interface disturbance (unevenness). In the case of sequential multilayer coating, when the upper layer coating solution is applied, the lower layer formed is redissolved, the upper layer and lower layer liquids are mixed together, and mixing between adjacent layers and interface disturbance (unevenness) occur. May occur. Moreover, since the coating film obtained by simultaneous multilayer coating is stacked in an undried liquid state, mixing between adjacent layers and interface disturbance (unevenness) are more likely to occur.

Since each refractive index layer of the ultraviolet shielding laminated portion reflects the ultraviolet region, the thickness of the refractive index layer is thinner than when reflecting a long wavelength region such as the near infrared region. Therefore, the mixing between the adjacent layers can affect the optical characteristics more.

The reflection characteristics are improved by making the average saponification degree of polyvinyl alcohol contained in the high refractive index layer different from the average saponification degree of polyvinyl alcohol contained in the low refractive index layer. Such an effect is considered to be a result of suppression of interlayer mixing. By using polyvinyl alcohol resins with different degrees of saponification, even when the high refractive index layer and the low refractive index layer are stacked in an undried liquid state, even if the layers are mixed somewhat, the solvent water is volatilized during the drying process. When concentrated, polyvinyl alcohol resins with different degrees of saponification undergo phase separation, and the force to minimize the area of the interface of each layer is activated, so inter-layer mixing is suppressed and interface disturbance is reduced. Estimated. Thus, interlayer mixing is suppressed, and the disturbance of the interface is reduced, so that the ultraviolet shielding film of the present invention is excellent in light reflectivity at a desired wavelength. Moreover, since interlayer mixing is suppressed, it is thought that the haze of a film also falls.

However, the above mechanism is an estimation and does not limit the scope of the present invention.

The average degree of saponification of polyvinyl alcohol in each refractive index layer is determined in consideration of the content ratio in the refractive index layer. That is, the average degree of saponification = Σ (degree of saponification of each polyvinyl alcohol (mol%) × content of each polyvinyl alcohol in each refractive index layer (%) / 100 mass (%)). For example, the refractive index layer is polyvinyl alcohol A (the mass ratio in the refractive index layer (the mass content (%) of each polyvinyl alcohol in each refractive index layer / 100 mass (%)): Wa, the saponification degree: Sa (mol %)), Polyvinyl alcohol B (mass ratio in the refractive index layer: Wb, saponification degree: Sb (mol%)), polyvinyl alcohol C (mass ratio in the refractive index layer: Wc, saponification degree: Sc (mol) %)), The average degree of saponification = (Wa × Sa + Wb × Sb + Wc × Sc / (Wa + Wb + Wc)).

The difference (absolute value) between the average saponification degree of polyvinyl alcohol contained in the high refractive index layer and the average saponification degree of polyvinyl alcohol contained in the low refractive index layer is preferably 1 mol% or more, and is 3 mol% or more. Preferably, it is 5 mol% or more, more preferably 8 mol% or more. If it is such a range, the effect of this invention will increase further and film characteristics (a reflection characteristic, visible light transmittance, etc.) will improve more. The difference between the average saponification degree of polyvinyl alcohol contained in the high refractive index layer and the average saponification degree of polyvinyl alcohol contained in the low refractive index layer is preferably as far as possible, but the dissolution of polyvinyl alcohol in water is preferable. From the viewpoint of properties, it is preferably 20 mol% or less.

The content of the water-soluble resin in the refractive index layer is not particularly limited, but is preferably 1 to 50% by mass, more preferably, based on the total mass (solid content) of each refractive index layer. 5 to 30% by mass.

In the low refractive index layer, a fluorine-containing polymer may be used in order to adjust the refractive index difference. Examples of the fluorine-containing polymer include a polymer mainly containing a fluorine-containing unsaturated ethylenic monomer component.

Examples of the fluorine-containing unsaturated ethylenic monomer include a fluorine-containing alkene, a fluorine-containing acrylic acid ester, a fluorine-containing methacrylate ester, a fluorine-containing vinyl ester, a fluorine-containing vinyl ether, and the like. And fluorine-containing unsaturated ethylenic monomers described in paragraph “0181” of the No.

Examples of monomers that can be copolymerized with fluorine-containing monomers include, for example, ethylene, propylene, butene, vinyl acetate, vinyl ethyl ether, vinyl ethyl ketone, methyl acrylate, methyl methacrylate, ethyl acrylate, propyl acrylate, butyl acrylate, Ethyl methacrylate, propyl methacrylate, butyl methacrylate, methyl-α-fluoroacrylate, ethyl-α-fluoroacrylate, propyl-α-fluoroacrylate, butyl-α-fluoroacrylate, cyclohexyl-α-fluoroacrylate, hexyl-α-fluoroacrylate , Benzyl-α-fluoroacrylate, acrylic acid, methacrylic acid, α-fluoroacrylic acid, styrene, styrene sulfonic acid, methoxypolyethyleneglycol And rumethacrylate.

The refractive index of a single resin of a fluorine-containing ethylenically unsaturated monomer is in the range of approximately 1.33 to 1.42, and the refractive index of a single resin polymer of a fluorine-free monomer that can be copolymerized. Can be used as a fluorine-containing polymer having a desired refractive index by copolymerizing these at an arbitrary ratio of 1.44 or more, and having a desired refractive index by mixing with the polyvinyl alcohol at an arbitrary ratio. Can be used. The content ratio (in terms of solid content) in the refractive index layer of such a fluoropolymer and polyvinyl alcohol is preferably polyvinyl alcohol: fluoropolymer = 1: 0.1-5.

(Metal oxide)
At least one of the high refractive index layer and the low refractive index layer preferably contains a metal oxide (particle) together with the water-soluble resin. By containing metal oxide particles, the refractive index difference between the refractive index layers can be increased, and the reflection characteristics are improved. In particular, metal oxides such as titanium oxide and zirconium oxide absorb ultraviolet rays and improve ultraviolet shielding properties. Therefore, at least the high refractive index layer preferably contains metal oxide particles, and the refractive index difference is further increased. Therefore, it is more preferable that both the high refractive index layer and the low refractive index layer contain metal oxide particles.

The metal oxide particles preferably have an average particle size of 100 nm or less. When the average particle diameter of the metal oxide particles to be used is 100 nm or less, light scattering can be suppressed and the accuracy in controlling the film thickness of each refractive index layer in the ultraviolet shielding film can be improved. Here, in this specification, an average particle diameter refers to a primary average particle diameter. The primary average particle size referred to in this specification is the measurement of the particle size of 1,000 arbitrary particles by a method of observing a particle image appearing on the cross section or surface of the particle itself or the refractive index layer with an electron microscope. , The average value. Here, the particle diameter of each particle is a diameter (projected area circle equivalent diameter) when a circle equal to the projected area is assumed. When the metal oxide particles are coated (for example, silica-attached titanium dioxide described later), the average particle diameter of the metal oxide particles is the base (the silica-attached titanium dioxide). In this case, it means the average particle diameter of titanium dioxide before treatment).

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

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

Further, the particle diameter of the metal oxide particles of the low refractive index layer can be determined by the volume average particle diameter in addition to the primary average particle diameter.

The colloidal silica used in the present invention is obtained by heating and aging a silica sol obtained by metathesis with an acid of sodium silicate or the like and passing through an ion exchange resin layer. For example, JP-A-57-14091, JP-A-60-219083, JP-A-60-218904, JP-A-61-20792, JP-A-61-188183, JP-A-63-17807, JP-A-4-93284 JP-A-5-278324, JP-A-6-92011, JP-A-6-183134, JP-A-6-297830, JP-A-7-81214, JP-A-7-101142 , JP-A-7-179029, JP-A-7-137431, and International Publication No. 94/26530. It is intended.

Such colloidal silica may be a synthetic product or a commercially available product. Examples of commercially available products include the Snowtex series (Snowtex OS, OXS, S, OS, 20, 30, 40, O, N, C, etc.) sold by Nissan Chemical Industries.

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

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

The content of the metal oxide particles in the low refractive index layer is preferably 20 to 90% by mass, and more preferably 30 to 85% by mass with respect to 100% by mass of the solid content of the low refractive index layer. More preferably, it is 40 to 70% by mass. When it is 20% by mass or more, a desired refractive index is obtained, and when it is 90% by mass or less, the coatability is good, which is preferable.

(Metal oxide in the high refractive index layer)
As the metal oxide particles of the high refractive index layer according to the present invention, for example, titanium dioxide, zirconium oxide, zinc oxide, alumina, colloidal alumina, lead titanate, red lead, yellow lead, zinc yellow, chromium oxide, oxidized oxide Examples thereof include ferric iron, iron black, copper oxide, magnesium oxide, magnesium hydroxide, strontium titanate, yttrium oxide, niobium oxide, europium oxide, lanthanum oxide, zircon, and tin oxide. Among these, metal oxide particles such as titanium dioxide and zirconium oxide are preferable because they can absorb light in the ultraviolet region.

In the present invention, in order to form a transparent and higher refractive index layer having a higher refractive index, the high refractive index layer is made of high refractive index metal oxide fine particles such as titanium dioxide and zirconium oxide, that is, fine particles of titanium oxide and fine particles of zirconium oxide. It is preferable to contain. In that case, it is preferable to contain rutile (tetragonal) titanium oxide particles.

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

As the titanium oxide particles of the present invention, it is preferable to use particles in which the surface of an aqueous titanium oxide sol is modified to stabilize the dispersion state.

As the method for preparing the aqueous titanium oxide sol, any conventionally known method can be used. For example, JP-A-63-17221, JP-A-7-819, JP-A-9-165218, See the matters described in Kaihei 11-43327, JP-A-63-17221, JP-A-7-819, JP-A-9-165218, JP-A-11-43327, etc. Can do.

As for other methods for producing titanium oxide particles, for example, “Titanium oxide—physical properties and applied technology”, Kiyono Manabu, p. 255 to 258 (2000), Gihodo Publishing Co., Ltd., or paragraph number 0011 to WO2007 / 039953. The method of the step (2) described in 0023 can be referred to.

In the production method according to the above step (2), titanium dioxide hydrate is treated with at least one basic compound selected from the group consisting of alkali metal hydroxides or alkaline earth metal hydroxides. After the step (1), the titanium dioxide dispersion obtained comprises a step (2) of treating with a carboxylic acid group-containing compound and an inorganic acid.

Furthermore, another method for producing metal oxide particles including titanium oxide particles is disclosed in JP-A-2000-053421 (comprising alkyl silicate as a dispersion stabilizer, and silicon in the alkyl silicate is changed to SiO _2. A titanium oxide sol having a weight ratio (SiO ₂ / TiO ₂ ) of 0.7 to 10 of the amount converted to TiO ₂ and the amount converted to TiO ₂ in titanium oxide), JP 2000-063119 A (TiO ₂ -ZrO ₂ -SnO ₂ composite colloidal particles as the core, and the surface thereof coated with the composite oxide colloidal particles of WO ₃ -SnO ₂ -SiO ₂ ) can be referred to .

Further, the titanium oxide particles may be coated with a silicon-containing hydrated oxide. Here, the “coating” means a state in which a silicon-containing hydrated oxide is attached to at least a part of the surface of the titanium oxide particles. That is, the surface of the titanium oxide particles used as the metal oxide particles may be completely covered with a silicon-containing hydrated oxide, and a part of the surface of the titanium oxide particles is a silicon-containing hydrated oxide. It may be coated. From the viewpoint that the refractive index of the coated titanium oxide particles is controlled by the coating amount of the silicon-containing hydrated oxide, it is preferable that a part of the surface of the titanium oxide particles is coated with the silicon-containing hydrated oxide. .

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

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

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

As a method of coating titanium oxide particles with a silicon-containing hydrated oxide, it can be produced by a conventionally known method. For example, JP-A-10-158015 (Si / Al hydration to rutile titanium oxide) Oxide treatment; a method of producing a titanium oxide sol in which a hydrous oxide of silicon and / or aluminum is deposited on the surface of titanium oxide after peptization in the alkali region of the titanate cake), JP 2000-204301 A (A sol in which a rutile-type titanium oxide is coated with a complex oxide of Si and Zr and / or Al. Hydrothermal treatment), JP 2007-246351 (Oxidation obtained by peptizing hydrous titanium oxide) titanium to hydrosol, wherein ^R _{1 n SiX 4-n} (wherein ^{R 1} as stabilizer _C 1 -C ₈ alkyl group, glycidyloxy substituted _C 1 -C Alkyl or C ₂ -C ₈ alkenyl group, X is an alkoxy group, n is 1 or 2. Sodium silicate added in the alkaline range the compound having a complexing effect on organoalkoxysilanes or titanium oxide) Alternatively, it is possible to refer to matters described in, for example, a method for producing a titanium oxide hydrosol coated with a hydrous oxide of silicon by adding, adjusting pH, and aging a silica sol solution.

In addition, as the metal oxide particles contained in the high refractive index layer, core-shell particles produced by a known method can be used. For example, the following (i) to (v): (i) An aqueous solution containing titanium oxide particles is hydrolyzed by heating, or an aqueous solution containing titanium oxide particles is neutralized by adding an alkali, so that the average particle size is After obtaining 1 to 30 nm of titanium oxide, the titanium oxide particles and the mineral acid were mixed so that the molar ratio of titanium oxide particles / mineral acid was in the range of 1 / 0.5 to 1/2. The slurry is heat-treated at a temperature not lower than the boiling point of the slurry and not higher than the boiling point of the slurry, and then a silicon compound (for example, an aqueous sodium silicate solution) is added to the obtained slurry containing the titanium oxide particles. A method of removing impurities from the slurry of the obtained surface-treated titanium oxide particles (Japanese Patent Laid-Open No. 10-158015); (ii) hydrous titanium oxide A method of neutralizing a titanium oxide sol stabilized at a pH in an acidic range obtained by peptizing a titanium oxide of a monobasic acid or a salt thereof and an alkyl silicate as a dispersion stabilizer by a conventional method ( (Iii) Hydrogen peroxide and tin metal are maintained at a H ₂ O ₂ / Sn molar ratio of 2 to 3 at the same time or alternately, such as a titanium salt (eg, titanium tetrachloride). The mixture is added to the aqueous solution to form a basic salt aqueous solution containing titanium, and the basic salt aqueous solution is kept at a temperature of 50 to 100 ° C. for 0.1 to 100 hours to coagulate the composite colloid containing titanium oxide. An aggregate is formed, and then the electrolyte in the aggregate slurry is removed to produce a stable aqueous sol of composite colloidal particles comprising titanium oxide; silicates (eg, sodium silicate aqueous solution) A stable aqueous sol of composite colloidal particles containing silicon dioxide is produced by preparing an aqueous solution containing selenium and removing cations present in the aqueous solution; the resulting composite aqueous sol containing titanium oxide 100 parts by weight in terms of metal oxide TiO ₂ and ₂ to 100 parts by weight of the resulting composite aqueous sol containing silicon dioxide in terms of metal oxide SiO ₂ are mixed to remove anions (Iv) Hydrogen peroxide is added to a hydrous titanic acid gel or sol to dissolve the hydrous titanic acid, and the resulting aqueous peroxotitanic acid solution is heated and aged at 80 ° C. for 1 hour (Japanese Patent Laid-Open No. 2000-063119). After adding a silicon compound or the like and heating to obtain a dispersion of a core particle composed of a composite solid solution oxide having a rutile structure, and then adding the silicon compound or the like to the dispersion of the core particle Heating, forming a coating layer on the surface of the core particles, obtaining a sol in which the composite oxide particles are dispersed, and further heating (JP 2000-204301); (v) peptizing hydrous titanium oxide To the obtained titanium oxide hydrosol, an organoalkoxysilane (R ¹ nSiX _4-n ) as a stabilizer or a compound selected from hydrogen peroxide and an aliphatic or aromatic hydroxycarboxylic acid is added, and the pH of the solution is increased. The core-shell particles produced by the method of performing desalting treatment after adjusting to 3 to less than 9 and performing aging (Japanese Patent No. 4550753).

The core-shell particles may be those in which the entire surface of the titanium oxide particles as a core is coated with a silicon-containing hydrated oxide, and a part of the surface of the titanium oxide particles as a core is covered with a silicon-containing hydrated oxide. It may be coated with.

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

The content of the metal oxide particles in the high refractive index layer is preferably 15 to 90% by mass and more preferably 20 to 85% by mass with respect to 100% by mass of the solid content of the high refractive index layer. The content is preferably 30 to 85% by mass from the viewpoint of improving the reflectance.

[Surfactant]
Each refractive index layer preferably contains a surfactant from the viewpoint of coatability.

An anionic surfactant, a nonionic surfactant, an amphoteric surfactant, and the like can be used as the surfactant used for adjusting the surface tension during coating, but an anionic surfactant is more preferable. Preferable compounds include those containing a hydrophobic group having 8 to 30 carbon atoms and a sulfonic acid group or a salt thereof in one molecule.

Anionic surfactants include alkyl benzene sulfonate, alkyl naphthalene sulfonate, alkane or olefin sulfonate, alkyl sulfate ester salt, polyoxyethylene alkyl or alkyl aryl ether sulfate ester, alkyl phosphate, alkyl diphenyl ether A surfactant selected from the group consisting of disulfonates, ether carboxylates, alkylsulfosuccinates, α-sulfo fatty acid esters and fatty acid salts, condensates of higher fatty acids with amino acids, naphthenates, etc. may be used. it can. Anionic surfactants preferably used are alkylbenzene sulfonates (especially those of linear alkyls), alkanes or olefin sulfonates (especially secondary alkane sulfonates, α-olefin sulfonates), alkyl sulfates Salts, polyoxyethylene alkyl or alkylaryl ether sulfates (especially polyoxyethylene alkyl ether sulfates), alkyl phosphates (especially monoalkyl type), ether carboxylates, alkyl sulfosuccinates, α-sulfo fatty acid esters and A surfactant selected from the group consisting of fatty acid salts, and alkylsulfosuccinate is particularly preferable.

The content of the surfactant in each refractive index layer is preferably 0.001 to 0.5% by mass, and preferably 0.005 to 0.3% by mass, based on 100% by mass of the solid content of the refractive index layer. It is more preferable.

(Polymer dispersant)
Each refractive index layer preferably contains a polymer dispersant from the viewpoint of dispersion stability of the coating solution. The polymer dispersant refers to a polymer dispersant having a weight average molecular weight of 10,000 or more. Preferably, the polymer has a hydroxyl group substituted at the side chain or terminal. For example, a polymer obtained by copolymerizing 2-ethylhexyl acrylate with an acrylic polymer such as sodium polyacrylate or polyacrylamide, polyethylene glycol or the like. Examples include polyethers such as polypropylene glycol, polyvinyl alcohol, and the like. Commercially available polymer dispersants may be used, and examples of such polymer dispersants include Marialim AKM-0531 (manufactured by NOF Corporation). The content of the polymer dispersant is preferably 0.1 to 10% by mass in terms of solid content with respect to the refractive index layer.

[Emulsion resin]
The high refractive index layer or the low refractive index layer may further contain an emulsion resin. By including the emulsion resin, the flexibility of the film is increased and the workability such as sticking to glass is improved.

An emulsion resin is a resin in which fine resin particles having an average particle diameter of about 0.01 to 2.0 μm, for example, are dispersed in an emulsion state in an aqueous medium. Obtained by emulsion polymerization using a molecular dispersant. There is no fundamental difference in the polymer component of the resulting emulsion resin depending on the type of dispersant used. Examples of the dispersant used in the polymerization of the emulsion include polyoxyethylene nonylphenyl ether in addition to low molecular weight dispersants such as alkylsulfonate, alkylbenzenesulfonate, diethylamine, ethylenediamine, and quaternary ammonium salt. , Polymer dispersing agents such as polyoxyethylene lauryl ether, hydroxyethyl cellulose, and polyvinylpyrrolidone. When emulsion polymerization is performed using a polymer dispersant having a hydroxyl group, the presence of hydroxyl groups is estimated on at least the surface of fine particles, and the emulsion resin polymerized using other dispersants has chemical and physical properties of the emulsion. Different.

The polymer dispersant containing a hydroxyl group is a polymer dispersant having a weight average molecular weight of 10,000 or more, and has a hydroxyl group substituted at the side chain or terminal. For example, an acrylic polymer such as sodium polyacrylate or polyacrylamide is used. Examples of such polymers include 2-ethylhexyl acrylate copolymer, polyethers such as polyethylene glycol and polypropylene glycol, and polyvinyl alcohol. Polyvinyl alcohol is particularly preferable.

Polyvinyl alcohol used as a polymer dispersant is an anion-modified polyvinyl alcohol having an anionic group such as a cation-modified polyvinyl alcohol or a carboxyl group in addition to ordinary polyvinyl alcohol obtained by hydrolysis of polyvinyl acetate. Further, modified polyvinyl alcohol such as silyl-modified polyvinyl alcohol having a silyl group is also included. Polyvinyl alcohol has a higher effect of suppressing the occurrence of cracks when forming the ink absorbing layer when the average degree of polymerization is higher, but when the average degree of polymerization is within 5000, the viscosity of the emulsion resin is not high, and at the time of production Easy to handle. Accordingly, the average degree of polymerization is preferably 300 to 5000, more preferably 1500 to 5000, and particularly preferably 3000 to 4500. The saponification degree of polyvinyl alcohol is preferably 70 to 100 mol%, more preferably 80 to 99.5 mol%.

Examples of the resin that is emulsion-polymerized with the above polymer dispersant include homopolymers or copolymers of ethylene monomers such as acrylic acid esters, methacrylic acid esters, vinyl compounds, and styrene compounds, and diene compounds such as butadiene and isoprene. Examples of the polymer include acrylic resins, styrene-butadiene resins, and ethylene-vinyl acetate resins.

[Other additives for refractive index layer]
The high refractive index layer and the low refractive index layer according to the present invention can contain various additives as required.

For example, ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988, and JP-A-62-261476, JP-A-57-74192, JP-A-57-87989, JP-A-60- No. 72785, 61-146591, JP-A-1-95091 and 3-13376, etc., and JP-A-59-42993 and 59-52689. Fluorescent brighteners, sulfuric acid, phosphoric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide described in JP-A-62-280069, JP-A-61-228771 and JP-A-4-219266 Various known additives such as pH adjusters such as potassium carbonate, antifoaming agents, lubricants such as diethylene glycol, preservatives, antistatic agents and matting agents It may contain.

(Resin support)
The resin support is used as a base material for the ultraviolet shielding laminate.

The resin support is preferably transparent in at least one of the infrared and visible wavelength regions. If it is transparent in the visible light region, it is useful for applications that require light in the visible light region, such as solar cell units, without impairing the design of the lower layer. Moreover, if it is transparent in the infrared region, light in the wavelength region of the infrared region is not blocked, so that it is useful in applications that require light in the infrared region. Therefore, for which wavelength range the resin support is transparent is appropriately selected depending on the use of the substrate on which the ultraviolet shielding film is used.

Transparent in the visible light region means that the average transmittance in the visible light region (400 to 800 nm) measured by a spectrophotometer is 75% or more, more preferably 80% or more, particularly 85%. The above is preferable. Further, being transparent in the infrared light region means that the average transmittance in the infrared light region (800 to 1400 nm) measured by a spectrophotometer is 75% or more, more preferably 80% or more. In particular, it is preferably 85% or more.

As the resin support, various resin supports can be used, and polyolefin (polyethylene, polypropylene, etc.), polyester (polyethylene terephthalate, polyethylene naphthalate, etc.), polyvinyl chloride, cellulose acetate, etc. can be used. Since the effect of the present invention that suppresses the deterioration of the resin support is remarkably obtained, the resin used for the resin support is preferably polyester. Although it does not specifically limit as polyester, It is preferable that it is polyester which has the film formation property which has a dicarboxylic acid component and a diol component as main structural components.

The main constituent dicarboxylic acid components include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenylethanedicarboxylic acid, Examples thereof include cyclohexane dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl thioether dicarboxylic acid, diphenyl ketone dicarboxylic acid, and phenylindane dicarboxylic acid. Examples of the diol component include ethylene glycol, propylene glycol, tetramethylene glycol, cyclohexanedimethanol, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyethoxyphenyl) propane, bis ( 4-Hydroxyphenyl) sulfone, bisphenol fluorene hydroxyethyl ether, diethylene glycol, neopentyl glycol, hydroquinone, cyclohexanediol and the like. Among the polyesters having these as main components, from the viewpoints of transparency, mechanical strength, dimensional stability, etc., dicarboxylic acid components such as terephthalic acid, 2,6-naphthalenedicarboxylic acid, diol components such as ethylene glycol and 1 Polyester having 1,4-cyclohexanedimethanol as the main constituent is preferred. Among these, polyesters mainly composed of polyethylene terephthalate and polyethylene naphthalate, copolymerized polyesters composed of terephthalic acid, 2,6-naphthalenedicarboxylic acid and ethylene glycol, and mixtures of two or more of these polyesters are mainly used. Polyester as a constituent component is preferable.

The thickness of the resin support used in the present invention is preferably 10 to 300 μm, particularly 20 to 150 μm. In addition, two resin supports may be stacked, and in this case, the type may be the same or different.

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

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

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

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

[Method for producing ultraviolet shielding film]
The method for producing the ultraviolet shielding film of the present invention is not particularly limited, and at least one unit composed of a resin layer, a high refractive index layer, and a low refractive index layer can be formed on the resin support. Any method can be used.

The method of laminating the ultraviolet shielding laminate and the resin layer is preferably a film formation method by coating because it can increase the area and preferably contains a water-soluble resin. Application or simultaneous multi-layer application may be used, but simultaneous multi-layer application is preferable because productivity is improved.

Examples of the coating method include a roll coating method, a rod bar coating method, an air knife coating method, a spray coating method, a curtain coating method, or US Pat. Nos. 2,761,419 and 2,761,791. A slide bead coating method using an hopper, an extrusion coating method, or the like is preferably used.

The solvent for preparing the high refractive index layer coating solution, the low refractive index layer coating solution and the resin layer coating solution is not particularly limited, but water, an organic solvent, or a mixed solvent thereof is preferable. In the present invention, since a water-soluble resin can be used as a suitable resin, an aqueous solvent can be used. Compared to the case where an organic solvent is used, the aqueous solvent does not require a large-scale production facility, so that it is preferable in terms of productivity and also in terms of environmental conservation.

Examples of the organic solvent include alcohols such as methanol, ethanol, 2-propanol and 1-butanol, esters such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate, diethyl ether, Examples thereof include ethers such as propylene glycol monomethyl ether and ethylene glycol monoethyl ether, amides such as dimethylformamide and N-methylpyrrolidone, and ketones such as acetone, methyl ethyl ketone, acetylacetone and cyclohexanone. These organic solvents may be used alone or in combination of two or more. From the viewpoint of environment and simplicity of operation, the solvent of the coating solution is preferably water or a mixed solvent of water and methanol, ethanol, or ethyl acetate, and more preferably water.

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

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

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

Further, the concentration of the resin in the resin layer coating solution is preferably 0.5 to 10% by mass.

The method for preparing the high refractive index layer coating solution, the low refractive index layer coating solution, and the resin layer coating solution is not particularly limited. For example, metal oxide particles, a resin, and other additives that are added as necessary. The method of adding and stirring and mixing is mentioned. At this time, the order of addition of the respective components is not particularly limited, and the respective components may be sequentially added and mixed while stirring, or may be added and mixed at one time while stirring. If necessary, it is further adjusted to an appropriate viscosity using a solvent.

In the present invention, it is preferable to form the high refractive index layer using an aqueous high refractive index coating solution prepared by adding and dispersing rutile type titanium oxide having a volume average particle size of 100 nm or less.

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

The viscosity of the high refractive index layer coating solution and the low refractive index layer coating solution during simultaneous multilayer coating is not particularly limited. However, when the slide bead coating method is used, the preferable temperature range of the coating solution is preferably 5 to 100 mPa · s, more preferably 10 to 50 mPa · s. When the curtain coating method is used, the preferable temperature range of the coating solution is preferably 5 to 1200 mPa · s, more preferably 25 to 500 mPa · s. If it is the range of such a viscosity, simultaneous multilayer coating can be performed efficiently.

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

The conditions for the coating and drying method are not particularly limited. For example, in the case of the sequential coating method, first, a resin layer coating solution heated to 30 to 60 ° C. is coated on the substrate and dried to form a layer. Thereafter, either one of the coating liquid for the high refractive index layer and the coating liquid for the low refractive index layer is coated on this layer and dried, and further, the coating liquid for the high refractive index layer and the coating liquid for the low refractive index layer The other coating liquid is applied onto this layer and dried to form a laminated film precursor (unit). Next, the number of units necessary for expressing the desired shielding performance is successively applied and dried by the above method to obtain a laminated film precursor. When drying, it is preferable to dry the formed coating film at 30 ° C. or higher. For example, drying is preferably performed in the range of a wet bulb temperature of 5 to 50 ° C. and a film surface temperature of 5 to 100 ° C. (preferably 10 to 50 ° C.). For example, hot air of 40 to 60 ° C. is blown for 1 to 5 seconds. dry. As a drying method, warm air drying, infrared drying, and microwave drying are used. Further, drying in a multi-stage process is preferable to drying in a single process, and it is more preferable to set the temperature of the constant rate drying section <the temperature of the rate-decreasing drying section. In this case, the temperature range of the constant rate drying section is preferably 30 to 60 ° C., and the temperature range of the decreasing rate drying section is preferably 50 to 100 ° C.

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

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

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

The set time is adjusted by adjusting the concentration of the water-soluble resin and the metal oxide particles, and adding other components such as various known gelling agents such as gelatin, pectin, agar, carrageenan and gellan gum. Can be adjusted.

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

The coating thickness of the resin layer coating solution, the coating solution for the high refractive index layer, and the coating solution for the low refractive index layer may be applied so as to have a preferable dry thickness as described above.

[Membrane design]
The ultraviolet shielding film of the present invention has an ultraviolet shielding laminated portion including at least one unit obtained by laminating a high refractive index layer and a low refractive index layer. Preferably, it has a multilayer optical interference film in which a high refractive index layer and a low refractive index layer are alternately laminated on one side or both sides of a resin support.

From the viewpoint of productivity, the total number of layers of the high refractive index layer and the low refractive index layer per side of the resin support is preferably 100 layers or less, more preferably 45 layers or less. The lower limit of the total number of layers of the high refractive index layer and the low refractive index layer per side of the resin support is not particularly limited, but is preferably 5 layers or more. In consideration of light scattering and reflection intensity, the range of the total number of high refractive index layers and low refractive index layers per side is preferably 7 to 23 layers.

Note that the preferable range of the total number of the high refractive index layer and the low refractive index layer is applicable even when laminated on only one side of the resin support, and is simultaneously laminated on both sides of the resin support. Even in cases, it can be adapted. When laminated on both surfaces of the resin support, the total number of high refractive index layers and low refractive index layers on one surface of the resin support and the other surface may be the same or different. Good. In the ultraviolet shielding film of the present invention, the lowermost layer and the outermost layer of the ultraviolet shielding laminated part may be either a high refractive index layer or a low refractive index layer. However, by adopting a layer structure in which the low refractive index layer is located in the lowermost layer and the outermost layer, adhesion to the lowermost resin support, blowing resistance of the uppermost layer, hard coat layer to the uppermost layer, etc. From the viewpoint of excellent coating properties and adhesiveness, the ultraviolet shielding film of the present invention preferably has a layer structure in which the lowermost layer and the outermost layer are low refractive index layers. The lowermost layer here refers to the lowermost layer when the ultraviolet shielding laminated portion is formed by coating, and the outermost layer refers to the outermost layer when the ultraviolet shielding laminated portion is formed by coating.

In general, in an ultraviolet shielding film, it is preferable to design a large difference in refractive index between a high refractive index layer and a low refractive index layer from the viewpoint that the reflectance for a desired light beam can be increased with a small number of layers. . In the present invention, the difference in refractive index between at least two adjacent layers (high refractive index layer and low refractive index layer) is preferably 0.1 or more, more preferably 0.25 or more, and further preferably 0. .3 or more, more preferably 0.35 or more, and most preferably 0.4 or more. The upper limit is not particularly limited, but is usually 1.4 or less.

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

When the high refractive index layer and the low refractive index layer are alternately laminated in the ultraviolet shielding film, the refractive index difference between the high refractive index layer and the low refractive index layer is within the range of the preferred refractive index difference. Is preferred. However, for example, when the outermost layer is formed as a layer for protecting the film or when the lowermost layer is formed as an adhesion improving layer with the substrate, the above-mentioned preferable refraction is performed with respect to the outermost layer and the lowermost layer. A configuration outside the range of the rate difference may be used.

Since reflection at the interface between adjacent layers depends on the refractive index ratio between layers, the larger this refractive index ratio, the higher the reflectance. In addition, when the optical path difference between the reflected light on the surface of the layer and the reflected light on the bottom of the layer is a relationship expressed by n · d = wavelength / 4 when viewed as a single layer film, the reflected light is controlled to be strengthened by the phase difference. And reflectivity can be increased. Here, n is the refractive index, d is the physical film thickness of the layer, and n · d is the optical film thickness. By using this optical path difference, reflection can be controlled. Using this relationship, the refractive index and film thickness of each layer are controlled to control the transmission of visible light and the reflection of ultraviolet light.

Further, it is preferable that the relationship between the average thickness dH of the high refractive index layer and the average thickness dL of the low refractive index layer satisfies the following formulas (1) and (2).

| DH−dL | <40 nm Formula (1)
| DH + dL | <150 nm Formula (2)
By satisfying the above formulas (1) and (2), the reflectance in the ultraviolet region can be increased. | DH−dL | is more preferably 25 nm or less. The lower limit of | dH−dL | is not particularly limited, but is preferably 5 nm or more in order to ensure an optical path difference. Further, | dH + dL | is more preferably 130 nm or less. The lower limit of | dH + dL | is usually 100 nm or more.

The wavelength having the maximum reflectance in the spectrum of the ultraviolet shielding film of the present invention is not particularly limited as long as it is in the ultraviolet shielding wavelength region, but is preferably designed to be 350 to 380 nm. This is because light with a wavelength shorter than 340 nm out of 280 nm to 380 nm, which is ultraviolet light harmful to the resin support, is absorbed by high refractive index metal oxides such as titanium oxide and zirconium oxide contained in the high refractive index layer. Alternatively, it is preferable to design the film so that a region of 350 to 380 nm which is difficult to cut with a metal oxide or an ultraviolet absorber can be reflected.

The ultraviolet shielding film of the present invention preferably has a high visible light transmittance. A formed body in which an ultraviolet shielding laminated portion is formed on a resin support is prepared, and the average transmittance of the formed body at 400 to 2500 nm is preferably 60% or more, more preferably 70% or more, and 80 % Or more is more preferable. The average reflectance in the ultraviolet region (280 to 400 nm) is preferably 10% or more, and more preferably 20% or more.

The refractive index of the low refractive index layer is preferably 1.10 to 1.60, more preferably 1.30 to 1.55. The high refractive index layer preferably has a refractive index of 1.80 to 2.50, more preferably 1.80 to 2.20.

The thickness of each low refractive index layer (thickness after drying) is preferably 20 to 80 nm, more preferably 30 to 70 nm, and even more preferably 40 to 60 nm.

The thickness (thickness after drying) of the high refractive index layer is preferably 40 to 100 nm, more preferably 50 to 90 nm, and more preferably 60 to 80 nm.

The total thickness of the ultraviolet shielding film of the present invention is preferably 12 μm to 315 μm, more preferably 15 μm to 200 μm, and still more preferably 20 μm to 100 μm.

[Layer structure of UV shielding film]
The ultraviolet shielding film includes at least one unit in which a high refractive index layer and a low refractive index layer are laminated on a resin support. The ultraviolet shielding laminated portion may be formed only on one side of the resin support, or may be formed on both sides. In order to improve the reflectivity of the ultraviolet wavelength, it is preferable that the ultraviolet shielding laminated portion is formed on both surfaces of the resin support. In addition, when the ultraviolet shielding laminated portion is formed on both surfaces of the resin support, a resin layer may be provided on at least one of the ultraviolet shielding laminated portion and the resin support. Is preferably provided.

For the purpose of adding further functions on the resin support, on the resin support, under the resin support or on the outermost surface layer opposite to the resin support, the ultraviolet shielding film is an easy adhesion layer (adhesive layer), a hard coat layer, UV absorber-containing layer, conductive layer, antistatic layer, gas barrier layer, antifouling layer, deodorant layer, drip layer, slippery layer, wear resistant layer, antireflection layer, electromagnetic wave shielding layer, infrared absorbing layer, Printing layer, fluorescent light emitting layer, hologram layer, release layer, adhesive layer, adhesive layer, infrared cut layer (metal layer, liquid crystal layer), colored layer (visible light absorbing layer), interlayer film layer used for laminated glass, etc. One or more functional layers may be included.

In the case where the ultraviolet shielding laminated portion is exposed on the surface of a film that is susceptible to physical force, it is preferable to laminate a hard coat layer on the ultraviolet shielding laminated portion for the purpose of protecting the ultraviolet shielding laminated portion from scratches and the like. That is, a preferred embodiment of the present invention is an ultraviolet shielding film having a hard coat layer disposed on the ultraviolet light incident side with respect to the ultraviolet shielding laminated portion.

Further, in order to more effectively protect the member in the lower layer of the film from ultraviolet rays and from the deterioration of the resin support, the ultraviolet shielding film preferably contains an ultraviolet absorber. As a form which contains a ultraviolet absorber in a film, you may make it contain in a resin layer as mentioned above, and you may provide a ultraviolet absorber content layer separately. The arrangement position of the ultraviolet absorber-containing layer is not particularly limited, but the resin layer and the resin support are capable of absorbing the ultraviolet rays that do not hinder the incidence of ultraviolet rays to the ultraviolet shielding laminated portion and are not completely shielded by the ultraviolet shielding laminated portion. It is preferable to arrange | position between. It is desirable that it be disposed below the ultraviolet shielding laminate as viewed from the ultraviolet incident surface.

Further, the surface roughness (center line average roughness: Ra) of the layer adjacent to the resin layer is preferably less than 0.1 μm. The film thickness of the refractive index layer of the ultraviolet shielding film is thinner than the film thickness of the refractive index layer of the film that shields a wavelength region having a longer wavelength than the ultraviolet region. For this reason, when the surface roughness of the resin layer side surface of the lower layer of the resin layer is 0.1 μm or more, it is difficult to smoothly laminate the refractive index layers, which may affect the optical characteristics. In the form in which the ultraviolet shielding laminated portion and the resin layer are laminated on the resin support, an adhesive layer is usually interposed between the resin support and the ultraviolet shielding laminated portion. The surface roughness of the resin layer is less than 0.1 μm. In addition, as an adhesive layer, the adhesive layer described in the column of the following ultraviolet absorber content layer can be used. The surface roughness of the resin layer side surface of the lower layer of the resin layer is usually 0.01 μm or more.

(Hard coat layer)
For the purpose of protecting the ultraviolet shielding laminate from scratches, the ultraviolet shielding film preferably has at least a hard coat layer.

Examples of the curable resin used in the hard coat layer include a thermosetting resin and an active energy ray curable resin, but an active energy ray curable resin is preferable because of easy molding. Such curable resins can be used singly or in combination of two or more. As the curable resin, a commercially available product may be used, or a synthetic product may be used.

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

As the ultraviolet curable resin, for example, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, or an ultraviolet curable epoxy resin is preferable. Used. Of these, ultraviolet curable acrylate resins are preferred.

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

The UV curable polyester acrylate resin can be easily obtained by reacting a monomer such as 2-hydroxyethyl acrylate, glycidyl acrylate, or acrylic acid with a hydroxyl group or carboxyl group at the end of the polyester (see, for example, JP-A No. 1987-101). 59-151112).

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

UV curable polyol acrylate resins are ethylene glycol (meth) acrylate, polyethylene glycol di (meth) acrylate, glycerin tri (meth) acrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol. It is obtained by reacting monomers such as pentaacrylate, dipentaerythritol hexaacrylate, alkyl-modified dipentaerythritol pentaacrylate and the like.

Examples of thermosetting resins include inorganic materials typified by polysiloxane.

The starting material of the polysiloxane hard coat is represented by the general formula RmSi (OR ′) n. R and R ′ represent an alkyl group having 1 to 10 carbon atoms, and m and n are integers satisfying the relationship of m + n = 4. Specifically, tetramethoxysilane, tetraethoxysilane, tetra-iso-propoxysilane, tetra-n-polopoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, terapentaethoxy Silane, tetrapenta-iso-propoxysilane, tetrapenta-n-propoxysilane, tetrapenta-n-butoxysilane, tetrapenta-sec-butoxysilane, tetrapenta-tert-butoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxy Silane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethylethoxysilane, dimethylmethoxysilane, dimethylpropoxysilane, dimethylbutoxysilane, dimethyl Dimethoxysilane, dimethyl diethoxy silane, hexyl trimethoxy silane and the like. Γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N-β- ( N-aminobenzylaminoethyl) -γ-aminopropylmethoxysilane / hydrochloride, γ-glycidoxypropyltrimethoxysilane, aminosilane, methylmethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloro Propyltrilimethoxysilane, hexamethyldisilazane, vinyltris (β-methoxyethoxy) silane, and octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium chloride can also be used. A state in which a hydrolyzable group such as methoxy group or ethoxy group is substituted with a hydroxyl group is generally referred to as a polyorganosiloxane hard coat. When this is applied onto a substrate and cured by heating, a dehydration condensation reaction is promoted, and a hard coat is formed by curing and crosslinking. Among these polyorganosiloxane hard coats, those having an organic group that is not eliminated by hydrolysis are methyl groups have the highest weather resistance. Moreover, if it is a methyl group, since the methyl group is uniformly and densely distributed on the surface after the hard coat film formation, the falling angle is also low. Therefore, in this application, it is preferable to use methylpolysiloxane.

If the polysiloxane hard coat is too thick, there is a risk that the hard coat layer will break due to stress, and if it is too thin, the hardness cannot be maintained. Therefore, the thickness is preferably 1 to 5 μm, and more preferably 1.5 to 3 μm.

Specific examples of the polyorganosiloxane hard coat include Surcoat Series (manufactured by Doken), SR2441 (Toray Dow Corning), KF-86 (Shin-Etsu Silicone), Perma-New (registered trademark) 6000 (California Hardcoating Company). Etc. can be used.

The blending amount of the cured resin in the hard coat layer is preferably 20 to 100% by mass and more preferably 30 to 99% by mass with respect to 100% by mass (in terms of solid content) of the hard coat layer. preferable.

Furthermore, as photosensitizers (radical polymerization initiators) for these resins, benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzyl methyl ketal and the like Alkyl ethers; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone (trade name Irgacure 184; BASF), 2-methyl-1 [4- (methylthio) phenyl] -2-mori Acetophenones such as folinopropan-1-one (trade name Irgacure 907; BASF); anthraquinones such as methylanthraquinone, 2-ethylanthraquinone and 2-amylanthraquinone; thioxanthone, 2,4-diethylthioxanthone, 2 Thioxanthones such as 4-diisopropyl thioxanthone; can be used benzophenone, 4,4-bis benzophenones such as methylamino benzophenone and azo compounds; acetophenone dimethyl ketal, benzil ketals such as dimethyl ketal. These may be used alone or in combination of two or more. In addition, tertiary amines such as triethanolamine and methyldiethanolamine; photoinitiators such as 2-dimethylaminoethylbenzoic acid and benzoic acid derivatives such as ethyl 4-dimethylaminobenzoate can be used in combination. it can. The use amount of these radical polymerization initiators is preferably 0.5 to 20 parts by mass, more preferably 1 to 15 parts by mass with respect to 100 parts by mass of the polymerizable component of the resin.

The thickness of the hard coat layer is preferably 0.1 to 20 μm, more preferably 1 to 15 μm, and more preferably 3 to 10 μm. If it is 0.1 μm or more, the hard coat property tends to be improved, and if it is 20 μm or less, the curl of the hard coat layer is large and the bending resistance tends to be lowered.

The hard coat layer can be produced by applying a cured resin layer forming composition (coating solution) by wire bar coating, spin coating or dip coating, and can also be produced by a dry film forming method such as vapor deposition. it can. The composition (coating liquid) can be applied and formed into a film by a continuous coating apparatus such as a die coater, a gravure coater, or a comma coater. In the case of a polysiloxane hard coat, after application, after drying the solvent, a heat treatment is required for 30 minutes to several days at a temperature of 50 ° C. or more and 150 ° C. or less in order to promote curing and crosslinking of the hard coat. To do. In consideration of the heat resistance of the coated substrate and the stability of the substrate when it is made into a roll, it is preferable to perform the treatment at 40 ° C. or more and 80 ° C. or less for 2 days or more. In the case of an active energy ray curable resin, the reactivity varies depending on the irradiation wavelength, the illuminance, and the light amount of the active energy ray, and therefore it is necessary to select an optimum condition depending on the resin to be used.

The composition for forming the cured resin layer (coating liquid) may contain a solvent, or may be appropriately contained and diluted as necessary. Examples of the organic solvent contained in the coating solution include hydrocarbons (toluene, xylene), alcohols (methanol, ethanol, isopropanol, butanol, cyclohexanol), ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone), It can be appropriately selected from esters (methyl acetate, ethyl acetate, methyl lactate), glycol ethers, and other organic solvents, or a mixture thereof can be used.

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

(UV absorber layer)
The ultraviolet absorber-containing layer may be in any form as long as it contains an ultraviolet absorber. In a preferred embodiment of the present invention, the adhesive layer contains an ultraviolet absorber.

The pressure-sensitive adhesive constituting the adhesive layer is not particularly limited. For example, acrylic pressure-sensitive adhesive, urethane acrylate pressure-sensitive adhesive, silicone pressure-sensitive adhesive, urethane pressure-sensitive adhesive, polyvinyl butyral pressure-sensitive adhesive, ethylene-vinyl acetate pressure-sensitive adhesive An agent etc. can be illustrated. Especially, since it has durability, a softness | flexibility, and toughness, the adhesive layer containing an acryl-urethane copolymer resin and a crosslinking agent (preferably 2 or more types) is used preferably.

The acrylic / urethane copolymer resin can be obtained by reacting a polyvalent isocyanate compound or polyurethane having an isocyanate group with an acrylic monomer. Examples of acrylic monomers used for acrylic / urethane copolymer resins include alkyl acrylates (alkyl groups such as methyl, ethyl, n-propyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, cyclohexyl, etc.), alkyl Methacrylate (Methyl, ethyl, n-propyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, cyclohexyl, etc. as alkyl groups), 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, Hydroxy group-containing monomers such as 2-hydroxypropyl methacrylate, acrylamide, methacrylamide, N-methyl methacrylamide, N-methyl acrylamide, N-methylol acrylamide, N Amide group-containing monomers such as methylol methacrylamide, N, N-dimethylol acrylamide, N-methoxymethyl acrylamide, N-methoxymethyl methacrylamide, N-butoxymethyl acrylamide, N-phenyl acrylamide, N, N-diethylaminoethyl acrylate, Carboxyl groups such as amino group-containing monomers such as N, N-diethylaminoethyl methacrylate, glycidyl group-containing monomers such as glycidyl acrylate and glycidyl methacrylate, acrylic acid, methacrylic acid and salts thereof (sodium salt, potassium salt, ammonium salt, etc.) Alternatively, a monomer containing a salt thereof can be used. It is preferable to copolymerize a crosslinkable functional group, and it is particularly preferable to copolymerize N-methylolacrylamide in terms of improving self-crosslinking property and crosslinking density. The copolymerization ratio of N-methylolacrylamide is preferably 0.5 to 5% by mass in terms of copolymerizability and the degree of crosslinking, and more preferably 1 to 3% by mass in view of the coating appearance. Examples of the crosslinking agent include melamine crosslinking agent, isocyanate crosslinking agent, aziridine crosslinking agent, epoxy crosslinking agent, methylolized or alkylolized urea, acrylamide, polyamide resin, oxazoline crosslinking agent, and carbodiimide. Cross-linking agents, various silane coupling agents, various titanate coupling agents and the like can be used. It is preferable that at least one of the crosslinking agents contains an oxazoline-based crosslinking agent and a carbodiimide-based crosslinking agent.

The ultraviolet absorber is not particularly limited, and examples of the organic type include benzophenone type, benzotriazole type, phenyl salicylate type, triazine type, hindered amine type, benzoate type, etc., and inorganic types include titanium oxide, zinc oxide, and oxide. Examples include cerium and iron oxide. In order to reduce the problem of bleeding out when a large amount of the ultraviolet absorber is contained, it is preferable to use a high molecular weight ultraviolet absorber having a weight average molecular weight of 1000 or more. The weight average molecular weight is preferably 1000 or more and 3000 or less.

Examples of the benzophenone ultraviolet absorber include 2,4-dihydroxy-benzophenone, 2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4-n-octoxy-benzophenone, 2-hydroxy-4-dodecyloxy-benzophenone, 2- Hydroxy-4-octadecyloxy-benzophenone, 2,2'-dihydroxy-4-methoxy-benzophenone, 2,2'-dihydroxy-4,4'-dimethoxy-benzophenone, 2,2 ', 4,4'-tetra And hydroxy-benzophenone. Commercially available products include “Seasorb 100”, “Seasorb 101”, “Seasorb 101S”, “Seasorb 102”, “Seasorb 103” manufactured by Sipro Kasei Co., Ltd., “Biosorb 100”, “Biosorb 110”, “Biosorb” manufactured by Kyodo Pharmaceutical. "130", Chemipro Kasei Corporation "Chemsorb 10", "Chemsorb 11", "Chemsorb 11S", "Chemsorb 12", "Chemsorb 13", "Chemsorb 111", BASF "Ubinur 400", BASF "Ubinur" "M-40", BASF "Ubinur MS-40", Cytec Industries "Thiasorb UV9", "Thiasorb UV284", "Thiasorb UV531", "Thiasorb UV24", Adeka "Adeka Stub 1413", "Adeka Stub LA" -51 " And the like.

Examples of benzotriazole ultraviolet absorbers include 2- (2′-hydroxy-5-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) benzotriazole 2- (2′-hydroxy-3′-t-butyl-5′-methylphenyl) benzotriazole, 2,2′-methylenebis [6- (2H-benzotriazol-2-yl) -4- (1, 1,3,3-tetramethylbutyl) phenol], 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol, and the like. Commercially available products include “LA31” from ADEKA Corporation, “Tinubin 234” from BASF, and the like.

Examples of the phenyl salicylate ultraviolet absorber include phenylsalicylate, 2-4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, and the like. Examples of the hindered amine ultraviolet absorber include bis (2,2,6,6-tetramethylpiperidin-4-yl) sebacate. Examples of commercially available products include “SEASORB 201” and “SEASORB 202” manufactured by Sipro Kasei Co., Ltd., “CHEMISORB 21” and “CHEMISORB 22” manufactured by Chemipro Kasei.

Examples of triazine ultraviolet absorbers include 2,4-diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-). Ethoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-propoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-) Butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2- Hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-octyloxyphenyl) -1,3,5-tria 2,4-diphenyl-6- (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-benzyloxyphenyl)- 1,3,5-triazine, [2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyl) oxyphenol] (Tinuvine 1577FF, trade name, Ciba Specialty) Chemicals), [2- [4,6-bis (2,4dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) phenol] and the like. Examples of commercially available products include “LA-46” manufactured by Adeka, “Tinubin 1577ED”, “Tinubin 400”, “Tinubin 405”, “Tinubin 460”, “Tinubin 477”, and “Tinubin 479” manufactured by BASF. .

Examples of the benzoate-based ultraviolet absorber include 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate (molecular weight 438.7; examples of commercially available products) Sumisorb 400) from Sumitomo Chemical Co., Ltd.

In addition to the above, as the ultraviolet absorber, a compound having a function of converting the energy held by ultraviolet rays into vibrational energy in the molecule and releasing the vibrational energy as heat energy or the like can be used. Furthermore, those that exhibit an effect when used in combination with an antioxidant or a colorant, or light stabilizers acting as a light energy conversion agent, called quenchers, can be used in combination. However, when using the above-mentioned ultraviolet absorber, it is necessary to select one in which the light absorption wavelength of the ultraviolet absorber does not overlap with the effective wavelength of the photopolymerization initiator. When a normal ultraviolet absorber is used, it is effective to use a photopolymerization initiator that generates radicals with visible light.

In addition, each of the above ultraviolet absorbers may be used in combination of two or more thereof as necessary. Further, if necessary, an ultraviolet absorber other than the above-described ultraviolet absorber, for example, a salicylic acid derivative, a substituted acrylonitrile, a nickel complex, or the like can be contained.

The content of the ultraviolet absorber in the ultraviolet absorber-containing layer is preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass.

The thickness of the ultraviolet absorber-containing layer is preferably 0.1 μm to 100 μm, more preferably 0.5 to 10 μm.

[Usage of UV shielding film]
The ultraviolet shielding film of the present invention can be applied to a wide range of fields, and its use is not particularly limited.

(1) Protective film for solar cell As one application of the ultraviolet shielding film, a protective film for solar cell may be mentioned.

Solar cells installed outdoors are required to have durability against solar radiation such as ultraviolet rays and infrared rays. For this reason, UV shielding films are useful, but UV shielding films do not block the necessary visible light (the visible light transmittance is difficult to decrease), and are environmentally resistant for long-term use and long-term storage. There is a demand for a surface protective film excellent in the above.

The ultraviolet shielding film of the present invention is useful as a protective film for solar cells because of its excellent weather resistance and low visible light transmittance.

Moreover, there is a flexible solar cell as one form of the solar cell. Since the flexible solar cell can form a curved surface, the flexible solar cell is configured so that it can be installed in a place where it cannot be applied to a crystalline silicon type battery manufactured using a glass plate. Moreover, since it is flexible, application to the portable use which can be rounded and folded is considered. However, as a film used to make a flexible solar cell, an expensive fluorine-based film must be used, and when a fluorine-based film is used as a cover film, the film is used to prevent water vapor transmission. It was necessary to increase the thickness of the film or to use a plurality of films. On the other hand, when considering the use of a non-fluorine-based material having high light transmittance, such as polyethylene terephthalate (PET), there is a deterioration due to ultraviolet rays in addition to a deterioration due to the influence of moisture.

Thus, when using a resin support that is susceptible to UV degradation such as PET in a flexible solar cell, the UV shielding film of the present invention is useful as a protective film.

(2) Protective film for image display media Image display media used for marking films used on the surfaces of exterior signage surface protection films, railway vehicles, automobiles, vending machines, etc. are dyes and inks made of ultraviolet rays. It is easy to fade. In addition, these image display media are often used outdoors for a long time, and exposure to ultraviolet rays is large. The ultraviolet shielding film of the present invention is useful as a protective film for such an image display medium.

(3) Ultraviolet sterilization The ultraviolet shielding film of the present invention can be used for the purpose of ultraviolet sterilization. That is, a preferred embodiment of the present invention is an ultraviolet shielding film for ultraviolet sterilization.

◎ Ultraviolet rays have a higher energy than other types of sunlight, and thus affect various things and the human body. The sterilizing action of ultraviolet rays has been well known. High-power, high-performance UV sterilization lamps have been developed, and sterilization by ultraviolet rays is used in various fields such as food and medicine. Many devices for sterilization using an ultraviolet lamp have been developed. However, the irradiation area is limited, and a power source is required to operate the lamp, and the places where it can be used are limited. There is an industrial product in which an ultraviolet reflection layer is formed on a glass or metal surface by sputtering in order to reflect ultraviolet rays at a target location instead of diffuse reflection. Since such an ultraviolet reflective layer is inferior in flexibility, it is difficult to change the shape. Since the ultraviolet shielding film of the present invention is flexible and is a polymer film, the shape can be changed with light weight. Moreover, if the ultraviolet rays contained in sunlight can be used, ultraviolet sterilization is possible without the need for a power supply or lamp replacement. In addition, the ultraviolet shielding film of the present invention preferably includes metal oxide particles that absorb ultraviolet rays having a short wavelength from around 340 nm, such as titanium oxide particles and zirconium oxide particles, in the ultraviolet shielding laminated portion. As described above, ultraviolet light having a wavelength longer than 340 nm is reflected by the interface between the high refractive index layer and the low refractive index layer of the ultraviolet shielding laminated portion. Preferably, ultraviolet light having a wavelength longer than 340 nm is used for ultraviolet sterilization. The effect of the UV shielding film is that the UV light harmful to the polymer reflects light of the wavelength used for UV sterilization, and the more harmful UV light from near 340 nm is absorbed by the metal oxide particles. Compared to the case where it is not contained, the ultraviolet durability is high.

(4) Sunlight reflecting film (film mirror)
The ultraviolet shielding film of the present invention is also suitably used in a light collecting device (solar thermal power generation) that reflects sunlight by a reflector (mirror) and condenses it in one place.

In the technology related to the light collecting device used in solar power generation, an attempt has been made to attach a resin light reflecting film with improved durability instead of a glass light reflecting member to a support and use it as a light reflecting member. Yes. Such a resinous light reflecting film preferably has a reflective metal layer (metal vapor deposition film) in order to reflect light in a wide wavelength range. That is, when used as a solar reflective film, the ultraviolet shielding film of the present invention preferably has a reflective metal layer (metal vapor deposition film) in addition to the resin support, the resin layer, and the ultraviolet shielding laminate. Furthermore, as a metal vapor deposition film, the thing which has silver with favorable sunlight reflectivity as a main component is preferable.

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

[Preparation of coating solution]
(Preparation of coating liquid L1 for low refractive index layer)
While heating and stirring 10 parts by weight of 3% by weight boric acid aqueous solution at 45 ° C., a 5% by weight aqueous solution of polyvinyl alcohol (PVA-117H, polymerization degree 1700, saponification degree 99.5 mol%, manufactured by Kuraray Co., Ltd.) 80 After adding parts by mass, 1 part by mass of a 1% by weight aqueous solution of a surfactant (Lapisol A30, manufactured by NOF Corporation) was added, and 9 parts by mass of pure water was added to prepare a coating solution L1 for a low refractive index layer. .

The single-film refractive index of the coating liquid L1 for the low refractive index layer was 1.50. In addition, the measurement of refractive index was described below.

(Preparation of coating liquid L2 for low refractive index layer)
22.5 parts by mass of colloidal silica (Snowtex OS, manufactured by Nissan Chemical Industries, solid content 20% by mass, average particle size 9.5 nm), 22.5 parts by mass of pure water, polyoxyalkylene dispersant (Marialim AKM- After adding 10 parts by weight of a 5% by weight aqueous solution of 0531, manufactured by NOF Corporation, and 10 parts by weight of a 3% by weight aqueous boric acid solution, the mixture was heated to 45 ° C. and stirred while polyvinyl alcohol (JC-25 (degree of polymerization) 2500, a saponification degree of 99.5 mol%, manufactured by Nippon Bijutsu Poval Co., Ltd.), JM-17 (polymerization degree of 1700, a saponification degree of 96.4 mol%, manufactured by Nihon Acetate Bipoval Co., Ltd.), and JP-15 (polymerization degree). 1500: 1500, degree of saponification 89.8 mol%, manufactured by Nihon Azuma Bi-Poval) and JL-25E (degree of polymerization 2500, degree of saponification 79.5 mol%, manufactured by Nihon Acetate-Poval) 43: 5: 40 parts by mass of a 5% by weight aqueous solution of 43 (solid content mass ratio), 1 part by mass of a 1% by weight aqueous solution of a surfactant (Rapidol A30, manufactured by NOF Corporation), and 2 parts by mass of pure water were added. Thus, a coating solution L2 for a low refractive index layer was prepared.

The single film refractive index of the coating liquid L2 for the low refractive index layer was 1.45.

(Preparation of coating liquid L3 for low refractive index layer)
After adding 10 parts by weight of a 3% by weight boric acid aqueous solution to 45 parts by weight of the following 10% by weight fluorine-containing polymer 1 aqueous solution, the mixture is heated to 45 ° C. and stirred with polyvinyl alcohol (JC-25 (degree of polymerization 2500, saponification). Degree 99.5 mol%, manufactured by Nihon Acetate Bi-Poval), JM-17 (degree of polymerization 1700, degree of saponification 96.4 mol%, Nihon Acetate-Poval), JP-15 (degree of polymerization 1500, saponification) Degree: 89.8 mol%, manufactured by Nihon Vitamin Bi-Poval) and JL-25E (polymerization degree: 2500, saponification degree: 79.5 mol%, Nihon Acetate: Poval) 43: 5: 9: 43 ( (Solid content mass ratio) mixture) 5 mass% aqueous solution 40 mass parts, surfactant (Lapisol A30, manufactured by NOF Corporation) 1 mass% aqueous solution 1 mass part is added, pure water 2 mass parts is added and low refraction Prepare coating liquid L3 for rate layer .

The single-film refractive index of the coating liquid L3 for the low refractive index layer was 1.40.

(Preparation of fluoropolymer 1 aqueous solution)
In a 1 L flask equipped with a reflux condenser under a nitrogen atmosphere, 6.4 g of 1H, 1H, 2H, 2H-heptadecafluorodecyl acrylate, 26.4 g of methoxypolyethylene glycol # 1000 methacrylate, and 34.9 g of methyl The methacrylate was added to a mixed solvent of 150 ml of isopropanol and 100 ml of pure water. After stirring at room temperature for 1 hour, 1.2 g of ammonium persulfate dissolved in 10 ml of pure water was added, and the mixture was heated and stirred at 65 ° C. for 16 hours. After cooling the obtained reaction mixture, isopropanol was distilled off with a rotary evaporator, and pure water was further added to prepare a 10% by mass aqueous solution containing a fluoropolymer 1. It was 16,000 when molecular weight was measured using GPC.

(Preparation of silica-attached titanium dioxide sol)
After adding 2 parts by mass of pure water to 0.5 parts by mass of 15.0% by mass titanium oxide sol (SRD-W, volume average particle size 5 nm, rutile type titanium dioxide particles, manufactured by Sakai Chemical Co., Ltd.), the mixture was heated to 90 ° C. . Subsequently, 1.3 parts by mass of an aqueous silicic acid solution (sodium silicate 4 (manufactured by Nippon Chemical Co., Ltd.) diluted with pure water so that the SiO ₂ concentration becomes 2.0% by mass) was gradually added. In an autoclave, heat treatment was performed at 175 ° C. for 18 hours, and after cooling, SiO ₂ was adhered to the surface by concentrating with an ultrafiltration membrane (the coating amount of silicon-containing hydrate was 4% by mass). Titanium sol (hereinafter, silica-attached titanium dioxide sol) was obtained in a solid content concentration of 20% by mass.

(Preparation of coating liquid H1 for high refractive index layer)
45 parts by mass of the silica-attached titanium dioxide sol (solid content 20.0% by mass), 2 parts by mass of a 5% by mass aqueous solution of polyvinyl alcohol (PVA-103, polymerization degree 300, saponification degree 98.5 mol%, manufactured by Kuraray Co., Ltd.) After adding 10 parts by weight of a 3% by weight aqueous boric acid solution and 10 parts by weight of a 2% by weight aqueous citric acid solution, the mixture was heated to 45 ° C. with stirring, and polyvinyl alcohol (PVA-117, polymerization degree 1700, saponification degree 98.98). 5 mol%, manufactured by Kuraray Co., Ltd.), 20 parts by mass of 5% by mass aqueous solution, 1 part by mass of 1% by mass aqueous solution of surfactant (Rapidol A30, manufactured by NOF Corporation), added with 12 parts by mass of pure water, and highly refractive. A rate layer coating solution H1 was prepared.

The single film refractive index of the coating liquid H1 for the high refractive index layer was 1.95.

(Preparation of coating liquid H2 for high refractive index layer)
30% by mass of zirconia sol (SZR-W, solid content 30% by mass, manufactured by Sakai Chemical Industry Co., Ltd., primary average particle size 3 nm), 5% by mass of polyoxyalkylene dispersant (Marialim AKM-053, manufactured by NOF Corporation) 10 parts by weight of an aqueous solution, 10 parts by weight of a 3% by weight aqueous solution of boric acid and 10 parts by weight of an aqueous solution of 2% by weight citric acid were added in this order, and the mixture was then heated to 45 ° C. and stirred with polyvinyl alcohol (PVA-217, polymerization degree 1700). 20 parts by weight of a 5% by weight aqueous solution of a saponification degree of 88.0 mol%, manufactured by Kuraray), and 1 part by weight of a 1% by weight aqueous solution of a surfactant (Rapidol A30, manufactured by NOF Corporation) were added, and 19 parts by weight of pure water was added. In addition, a coating liquid H2 for a high refractive index layer was prepared.

The single-film refractive index of the coating liquid H2 for the high refractive index layer was 1.85.

[Production of UV shielding film]
Example 1
(Preparation of sample 1)
Using a slide hopper coating apparatus capable of coating 21 layers, the low refractive index layer coating liquids L1 and L2 and the high refractive index layer coating liquid H1 are heated to 45 ° C. and heated to 45 ° C. On the polyethylene terephthalate film (Toyobo A4300: double-sided easy-adhesion layer), so that L1 is in contact with the polyethylene terephthalate film, then H1 is on L1, and H1 and L2 are alternated, Simultaneous multi-layer coating was performed. Immediately after coating, 5 ° C. cold air was blown for 5 minutes, and then 80 ° C. hot air was blown to dry to prepare Sample 1 having 21 layers. Therefore, the layer to which the coating liquid L1 for low refractive index layer is applied becomes a resin layer (a form in which the resin layer is formed adjacent to the ultraviolet shielding laminated portion).

The polyethylene terephthalate film had an average transmittance in the visible light region (400 to 800 nm) of 89% and an average transmittance in the infrared light region (800 to 1400 nm) of 88%.

The film thickness after drying is 0.5 μm for the layer coated with the coating liquid L1 for the low refractive index layer, the layer coated with the coating liquid L2 for the low refractive index layer is 64 nm for each layer, and the layer coated with the coating liquid H1 for the high refractive index. Each layer was 47 nm.

The average saponification degree of the polyvinyl alcohol of the low refractive index layer liquid L2 is 89.9 mol% (= 99.5 mol% × 0.43 + 96.4 mol% × 0.05 + 89.8 mol% × 0.09 + 79.5 mol% × 0). .43), and the average saponification degree of the polyvinyl alcohol of H1 in the coating solution for high refractive index is 98.5 mol%, so the difference in the average saponification degree of each refractive index layer is 8.6 mol%.

Example 2
(Preparation of sample 2)
Sample 2 was prepared in the same manner as Sample 1 except that the coating liquid extrusion pump flow rate was changed. The film thickness after drying is 0.5 μm for the layer coated with the coating liquid L1 for the low refractive index layer, the layer coated with the coating liquid L2 for the low refractive index layer is 64 nm for each layer, and the layer coated with the coating liquid H1 for the high refractive index. Each layer was 42 nm.

Example 3
(Preparation of sample 3)
Sample 3 was prepared in the same manner as Sample 1, except that the coating liquid extrusion pump flow rate of the low refractive index layer coating liquid L1 was changed. The film thickness after drying was 0.8 μm for the layer coated with the coating solution L1 for the low refractive index layer.

Example 4
(Preparation of sample 4)
Sample 4 was produced in the same manner as Sample 1 except that the coating liquid extrusion pump flow rate of the coating liquid L1 for the low refractive index layer was changed. The film thickness after drying was 1.0 μm for the layer coated with the coating solution L1 for the low refractive index layer.

Example 5
(Preparation of sample 5)
An acrylic / urethane copolymer resin easy-adhesive layer containing 1% by mass of an ultraviolet absorber tinuvin 477 (manufactured by BASF) as an ultraviolet absorber-containing layer on the surface of a 50 μm thick polyethylene terephthalate film instead of a polyethylene terephthalate film having a thickness of 50 μm Sample 5 was prepared in the same manner as Sample 1 except that a resin support formed by coating so as to have a dry film thickness of 1 μm was used.

(Creation of acrylic / urethane copolymer)
A reaction vessel equipped with a stirrer, a thermometer, a cooler, and a nitrogen gas inlet tube is 320.3 parts of polycarbonate diol having a molecular weight of 1000 (product name: Nippon Polan 981 manufactured by Nippon Polyurethane Industry Co., Ltd.), isophorone diisocyanate (Sumitomo Bayer Urethane Co., Ltd.) Product name: Dismodule I) 75.1 parts and 500 parts of toluene were added and reacted in a nitrogen atmosphere at 80 ° C. for 6 hours or more. When the isocyanate (NCO) concentration reaches the theoretical amount, 4.6 parts of 2-hydroxyethyl methacrylate and 100 parts of toluene are added, and further reacted at 80 ° C. for 6 hours until NCO at both ends of the urethane prepolymer disappears. A polymer linear urethane prepolymer solution having a resin solid content concentration of 40%, a viscosity of 4000 mPa · s (25 ° C.), and a weight average molecular weight of 34,000 was obtained.

Next, in a reaction vessel equipped with a stirrer, a thermometer, a cooler, a nitrogen gas introduction pipe, and a dropping device, 393.8 parts of a polymer linear urethane prepolymer solution, 184.4 parts of methyl methacrylate, 2- 8.1 parts of hydroxyethyl methacrylate, 1.75 parts of 1-thioglycerol and 82.7 parts of toluene were charged, and the temperature was raised to 105 ° C. with stirring. A mixed solution consisting of 3.5 parts of a radical initiator (trade name: ABN-E, manufactured by Nippon Hydrazine Industry Co., Ltd.) and 331 parts of toluene was added dropwise over 4 hours. After completion of the dropwise addition, the mixture was reacted at the same temperature for 6 hours to obtain an acrylic / urethane copolymer resin solution having a resin solid content concentration of 35%, a viscosity of 4000 mPa · s (25 ° C.), and a weight average molecular weight of 84000.

Example 6
(Preparation of sample 6)
Instead of a polyethylene terephthalate film having a thickness of 50 μm, a UV absorber Tinuvin 477 (manufactured by BASF) is used as a UV absorber-containing layer on the surface of a polyethylene naphthalate (PEN film) having a thickness of 100 μm (Teonex Q51 made by Teijin DuPont Films). Sample 6 was prepared in the same manner as Sample 1, except that a resin support formed by coating an acrylic / urethane copolymer resin easy-adhesion layer containing 1% by dry weight to a thickness of 1 μm was used.

The PEN film had an average transmittance in the visible light region (400 to 800 nm) of 86% and an average transmittance in the infrared light region (800 to 1400 nm) of 85%.

Example 7
(Preparation of sample 7)
The curable resin liquid described below is applied to the surface of the ultraviolet reflection laminated portion of sample 1 with a die coater, dried for 1 minute in a drying furnace having an average temperature of 85 ° C., and then the illuminance of the irradiated portion is 100 mW / Sample 7 was prepared in the same manner as Sample 1 except that the curable resin liquid coating layer was cured at cm ² with an irradiation dose of 0.5 J / cm ² to form a hard coat layer with a dry film thickness of 3 μm.

(Curable resin liquid)
165 parts by mass of MEK (methyl ethyl ketone) was mixed with 100 parts by mass of dipentaerythritol hexaacrylate (A-DPH solid content 100%, manufactured by Shin-Nakamura Chemical Co., Ltd.) and stirred. As a curing initiator, 5 parts by mass of Irgacure 907 (manufactured by BASF) was added to obtain a curable resin liquid having a viscosity of 5 mPa · s.

Example 8
(Preparation of sample 8)
Using a slide hopper coating apparatus capable of coating 21 layers, the low refractive index layer coating liquids L1 and L3 and the high refractive index layer coating liquid H2 are heated to 45 ° C. and heated to 45 ° C. On the polyethylene terephthalate film (Toyobo A4300: double-sided easy-adhesion layer), L1 is in contact with the polyethylene terephthalate film, then H2 is on L1, and H2 and L3 are alternately arranged. Simultaneous multi-layer coating was performed. Immediately after coating, 5 ° C. cold air was blown for 5 minutes, and then 80 ° C. hot air was blown to dry to prepare Sample 8 consisting of 21 layers.

The film thickness after drying is 0.5 μm for the layer coated with the coating liquid L1 for the low refractive index layer, the layer coated with the coating liquid L3 for the low refractive index layer is 66 nm, and the layer coated with the coating liquid H2 for the high refractive index. Each layer was 50 nm.

The average saponification degree of polyvinyl alcohol in the low refractive index layer liquid L3 is 89.9 mol%, and the average saponification degree of polyvinyl alcohol in H2 of the coating liquid for high refractive index is 88.0 mol%. The difference in the average saponification degree of each refractive index layer is 1.9 mol%.

Example 9
(Preparation of sample 9)
Sample 9 was prepared in the same manner as Sample 8, except that the coating liquid extrusion pump flow rate was changed. The film thickness after drying is 0.5 μm for the layer coated with the coating solution L1 for the low refractive index layer, the layer coated with the coating solution L3 for the low refractive index layer is 59 nm, and the layer coated with the coating solution H2 for the high refractive index. Each layer was 45 nm.

Comparative Example 1
(Preparation of sample 10)
Polyethylene terephthalate with a thickness of 50 μm heated to 45 ° C. while keeping the low refractive index layer coating solution L2 and the high refractive index layer coating solution H1 at 45 ° C. using a slide hopper coating device capable of coating 21 layers. On the film (Toyobo's A4300: double-sided easy-adhesion layer), a total of 21 layers were coated alternately so that the dry film thickness was 71 nm for each low refractive index layer and 53 nm for each high refractive index layer. Went.

Immediately after application, 5 ° C. cold air was blown for 5 minutes, and then 80 ° C. hot air was blown to dry to produce a multi-layer coated product consisting of 21 layers. Sample 10 is an example that does not have a resin layer of 0.5 μm or more.

Comparative Example 2
(Preparation of sample 11)
In Sample 1, Sample 11 was prepared in the same manner as Sample 1 except that the coating liquid extrusion pump flow rate was changed and the thickness of the layer coated with coating liquid L1 for low refractive index layer was changed to 0.3 μm. did.

Comparative Example 3
(Preparation of sample 12)
Using the same material as that of Example 1 of JP 2011-521289, an ultraviolet reflective film was manufactured by the same manufacturing method as that of Example 6 of JP 2011-521289.

Polyethylene naphthalate (PEN) (manufactured by 3M Company, St. Paul, MN) and polymethyl methacrylate (PMMA) commercially available as trade name VO44 acrylic resin (manufactured by Arkema Inc. Philadelphia, PA) The optical film was formed with a birefringent layer formed from PEN and a second polymer layer formed from PMMA. PEN and PMMA were coextruded through a multilayer polymer melt manifold to form a multilayer melt stream having 275 alternating layers of birefringent layers and second polymer layers. In addition, a pair of non-optical layers, also consisting of PEN, were coextruded as a protective surface layer on either side of the optical layer stack. This multilayer coextrusion melt stream was cast onto a chill roll at 22 meters per minute to form a multilayer molded web about 300 μm thick. The multilayer molded web was then heated at 135 ° C. for 10 seconds in a tenter oven before being biaxially oriented for a stretch ratio of 3.8 × 3.8. The oriented multilayer film was further heated to 225 ° C. for 10 seconds to increase the crystallinity of the PEN layer. All are obtained from CIBA Specialty Chemicals Corp, Tarryton, NY (PMMA-UVA / HALS), 5 wt% UV absorber obtained under the trade name TINUVIN 1577, and 0.15 wt% hindered amine obtained under the trade name CHIMASSORB 944 Arkema Inc., which is extrusion compounded with a light stabilizer. PMMA (VO44) from Philadelphia, PA; l. duPont de Nemours & Co. , Inc. , Wilmington, DE, under the trade name BYNEL E418, is co-extrusion coated on a multilayer film formed as described above, and at the same time for a forming tool with a finished surface of 893 kg / m (line Oriented into the nip at a molding line speed of 0.38 meters / second (75 feet per minute) at a temperature of 32 ° C. under a pressure of 50 pounds per inch. As for the reflectance of this multilayer film, an average reflectance of 95% was obtained at a wavelength of 360 nm.

Comparative Example 4
(Preparation of Sample 13)
Sample 13 was prepared in the same manner as Sample 1 except that Sample 1 was coated with the low refractive index layer coating liquid L2 instead of the low refractive index layer coating liquid L1.

[Evaluation of UV shielding film]
The following performance evaluation was performed on each of the ultraviolet shielding films (samples 1 to 13) produced above.

(Measurement of single film refractive index of each layer)
In order to measure the refractive index on the substrate, a sample in which each layer was applied as a single layer was prepared. After cutting this sample into 10 cm × 10 cm, the refractive index was determined according to the following method. Using Hitachi spectrophotometer U-4100 (solid sample measurement system), the surface opposite to the measurement surface (back surface) of each sample is roughened and then light absorption is performed with a black spray. Then, the reflection of light on the back surface was prevented, the reflectance at 550 nm was measured under the condition of regular reflection at 5 degrees, the average value was obtained, the average reflectance was obtained from the result, and the refractive index was further obtained.

(Measurement of initial transmittance, 5 degree regular reflectance)
The transmittance, the 5-degree regular reflectance and the transmittance on the light incident surface side of the produced laminated film were measured. The spectrophotometer U-4100 (solid sample measurement system) manufactured by Hitachi was used for the measurement. Both the transmittance and reflectance were measured in the wavelength range of 300 to 2000 nm.

(Evaluation of weather resistance)
The produced laminated film is allowed to stand for 30 days in an environment at a temperature of 85 ° C. and a relative humidity of 85%, and then irradiated with a xenon lamp (using a Suga Tester SX75, a black panel temperature of 63 ° C.). , Radiation intensity 180 W / m ² , 5000 hours) in an environment with a relative humidity of 50%. Next, after irradiation with a xenon lamp, the specular reflectance and transmittance are measured at 5 degrees in the same manner as described above, and the initial spectrum is compared in terms of spectrum shift, maximum transmittance and maximum reflectance, and according to the following evaluation. The film was evaluated.

・ Spectral shift (change in the maximum reflectance wavelength after the weather resistance test from the initial maximum reflectance wavelength)
5: Spectral shift from initial spectrum is less than 30 nm 4: Spectral shift from initial spectrum is less than 50 nm 3: Spectral shift from initial spectrum is from 50 nm to less than 100 nm 2: Spectral shift from initial spectrum is from 100 nm to less than 150 nm 1: Spectral shift from initial spectrum is 150 nm or more ・ Decrease in maximum reflectivity after weather resistance test relative to initial maximum reflectivity (= initial maximum reflectivity−maximum reflectivity after weather resistance test (%))
5: Maximum reflectivity decrease is less than 10% 4: Maximum reflectivity decrease is less than 30% 3: Maximum reflectivity decrease is 30% or more and less than 50% 2: Maximum reflectivity decrease is 50% or more and less than 70% 1: Maximum reflectivity 70% or more reduction in the rate ・ Reduction in maximum transmittance after the weather resistance test with respect to the initial maximum transmittance (= initial maximum transmittance−maximum transmittance after the weather resistance test (%))
5: Maximum transmittance decrease is less than 10% 4: Maximum transmittance decrease is less than 30% 3: Maximum transmittance decrease is 30% to less than 50% 2: Maximum transmittance decrease is 50% to less than 70% 1: Maximum transmission Rate reduction is 70% or more (Evaluation of adhesion)
After the above weather resistance evaluation, a cross-cut test based on JIS K 5600-5-6: 1999 was performed. Specifically, 11 cuts were made vertically and horizontally at intervals of 1 mm on the surface side on which the ultraviolet shielding laminate was formed, and 100 1 mm square grids were produced. A cellophane tape was affixed thereon, quickly peeled off at an angle of 90 degrees, the number of grids remaining without peeling was measured, and the evaluation of adhesion between the substrate and the ultraviolet shielding laminate was evaluated according to the following criteria. .

5: No separation is observed 4: The number of peeled grids is 1 or more and 5 or less 3: The number of peeled grids is 6 or more and 10 or less 2: Stripped grids The number is 11 or more and 20 or less 1: The number of peeled grids is 21 or more (Evaluation of scratch resistance)
Using a friction and wear tester (Tribo Station TYPE: 32, moving speed 4000 mm / min.) Using Shinto Kagaku Co., Ltd. A load of ² was applied and 20 reciprocations were made over a length of 10 cm. The scratch resistance evaluation of the ultraviolet shielding film was evaluated according to the following criteria.

5: Scratches are not recognized at all 4: 1 cm or more scratches are 1 or more and 5 or less 3: 1 cm or more scratches are 6 or more and 10 or less 2: 1 cm or more The number of scratches is 11 or more and 20 or less. The number of scratches of 1: 1 centimeter or more is 21 or more. Table 1 shows the evaluation results. In addition, it can be said that it is favorable if the evaluation rank is 3 or more in each evaluation.

As is clear from the results in Table 1, all the weather resistance evaluations of Examples 1 to 9 are within the range of 3 to 5. This is considered to be the following reason.

In the ultraviolet shielding films of Examples 1 to 9 according to the present invention, even when stored under high temperature and high humidity conditions, the spectral shift, the maximum transmittance decrease, and the maximum reflectance decrease were suppressed.

On the other hand, Comparative Example 1 contains a metal oxide in the coating layer in contact with the polymer film located below the reflective layer, and the ultraviolet rays that could not be reflected reacted with the metal oxide to oxidize the polymer film. It is considered that the deterioration of the polymer film caused yellowing, resulting in a spectral shift, a decrease in transmittance, and a decrease in reflectance.

Comparative Example 2 had a resin layer but did not satisfy the thickness specified in the present invention, and discoloration of the polyethylene terephthalate film occurred, resulting in a spectral shift, a decrease in transmittance, and a decrease in reflectance. This is presumably because the oxygen atoms bonded to the metal oxide particles contained in the ultraviolet shielding laminate were desorbed and promoted the oxidative deterioration of the adjacent polyethylene terephthalate film.

Comparative Example 3 is an ultraviolet reflective film in a film laminate, in which the ultraviolet shielding laminate does not contain a water-soluble resin. Comparative Example 3 did not show the desired performance in any of the evaluation items.

Comparative Example 4 had a resin-containing layer but contained metal particles, so that discoloration of the polyethylene terephthalate film occurred, causing a spectral shift, a decrease in transmittance, and a decrease in reflectance. This is considered to be because the metal oxide particles in the resin-containing layer promoted the oxidative deterioration of the adjacent polyethylene terephthalate film.

This application is based on Japanese Patent Application No. 2013-107958 filed on May 22, 2013, the disclosure content of which is incorporated by reference as a whole.

Claims (8)

1. An ultraviolet shielding film having an ultraviolet shielding laminated portion including a resin support and at least one unit obtained by laminating a high refractive index layer and a low refractive index layer,
   At least one of the high refractive index layer and the low refractive index layer contains a water-soluble resin and metal oxide particles,
   An ultraviolet shielding film in which a resin layer substantially free of metal oxide particles and having a film thickness of 0.5 μm or more is provided between the resin support and the ultraviolet shielding laminated portion.
2. The ultraviolet shielding film according to claim 1, wherein the resin layer contains a water-soluble resin.
3. The ultraviolet shielding film according to claim 1 or 2, wherein the resin layer is formed adjacent to the ultraviolet shielding laminated portion.
4. 4. The ultraviolet shielding film according to claim 1, wherein the metal oxide particles have an average particle size of 100 nm or less.
5. The ultraviolet shielding film according to any one of claims 1 to 4, wherein the resin support is transparent in at least one of an infrared wavelength region and a visible wavelength region.
6. The ultraviolet shielding film according to any one of claims 1 to 5, wherein the resin used for the resin support is polyester.
7. The ultraviolet shielding film according to any one of claims 1 to 6, further comprising a hard coat layer disposed on the ultraviolet light incident side of the ultraviolet shielding laminated portion.
8. The ultraviolet shielding film according to any one of claims 1 to 7, comprising an ultraviolet absorber.

Images