JP5029818B2 - Coating composition and optical member - Google Patents

Description

  The present invention relates to a coating composition containing a sodium magnesium fluoride sol having a low refractive index and a high light transmittance, and an optical member having a highly transparent and low refractive index coating formed from the coating composition.

  In general, on an image display surface such as a lens, a cathode ray tube, or a liquid crystal display, an antireflection treatment is performed in order to reduce reflection of external light such as sunlight or electric light and to increase the passage of light. Conventionally, a phenomenon has been known in which the reflectance is reduced by coating the surface of a transparent object with a transparent film having a low refractive index. It is possible to improve the visibility by providing an antireflection film using such a phenomenon on the display surface of the image display device. The antireflection film has a single layer structure in which a low refractive index layer having a low refractive index is provided on the display surface, or a plurality of middle to high refractive index layers on the display surface in order to further improve the antireflection effect. There is a multilayer structure in which a low refractive index layer for reducing the refractive index of the outermost surface is provided on the middle to high refractive index layer.

  As the above-described antireflection treatment, a vapor phase method and a coating method are generally known. As the vapor phase method, a physical method such as a vacuum deposition method and a sputtering method, and a chemical method such as a CVD method are known. . Examples of the coating method include a roll coating method, a gravure coating method, a slide coating method, a spray method, a dipping method, and a screen printing method.

  The transparent film obtained by the vapor phase method can form a high-quality transparent thin film, but the atmosphere must be controlled under a high vacuum, and a special heating device or ion generation acceleration device is required. Therefore, there is a problem that the manufacturing apparatus is complicated and large, and the manufacturing cost is inevitably high. In the vapor phase method, it is difficult to increase the area of the transparent thin film.

  On the other hand, in the case of the spray method among the application methods, there are problems such as poor utilization efficiency of the coating liquid and difficulty in controlling the film forming conditions, but the roll coating method, gravure coating method, slide coating method, In the case of the dipping method, the screen printing method, etc., the utilization efficiency of the coating liquid is good, which is advantageous in terms of mass production and equipment cost.

  As a transparent film obtained by a coating method, a coating composition containing silica or magnesium fluoride having a low refractive index as a filler is applied to the surface of an optical substrate and dried, or a coating containing silica or magnesium fluoride. It is known that the composition is applied to the surface of an optical substrate, dried, and then cured by UV irradiation or the like to form a low refractive index layer. Silica has a refractive index of 1.45 and magnesium fluoride is 1.378 to 1.390. To obtain an efficient coating as a low refractive index coating, it is necessary to select a filler having a lower refractive index as the material. There is.

  Sodium fluoride is known as a metal fluoride material having a lower refractive index than magnesium fluoride. According to Handbook of Chemistry and Physics (1970-1971, 51st edition) (Non-Patent Document 1), the refractive index of sodium fluoride is 1.327, and the refractive index of magnesium fluoride (1.378 to 1.390). Although lower, sodium fluoride is very difficult to make into fine particles or sols because it dissolves in water.

As a material for the water-insoluble metal fluoride, a sol composed of colloidal particles of sodium magnesium fluoride (NaF · MgF ₂ ) having an average particle diameter of 10 to 100 nm is proposed in Japanese Patent Application Laid-Open No. 7-69620 (Patent Document 1). Has been. According to Physics and Chemistry of Minerals 20, 419-424 (1993) (non-patent document 2), the refractive index of sodium magnesium fluoride is 1.364, which is useful as a material having a lower refractive index than silica and magnesium fluoride. It is.
JP 7-69620 A Handbook of Chemistry and Physics (1970-9711, 51st edition) Physics and Chemistry of Minerals 20, 419-424 (1993)

  The low refractive index coating used for the antireflection layer of the optical member is required to have high light transmittance simultaneously with prevention of external light reflection. Since the sodium magnesium fluoride sol described in Patent Document 1 has a low light transmittance, there is a problem that a sufficiently high light transmittance cannot be obtained when a low refractive index film is formed.

  An object of the present invention is to provide a coating composition capable of obtaining a low refractive index film having high light transmittance by using a sodium magnesium fluoride sol having high light transmittance, and an optical member having the low refractive index film. And

In order to solve the above problems, in the present invention, as a coating composition for obtaining a low refractive index film, a sol prepared with a sodium magnesium fluoride (NaF · MgF ₂ ) concentration of 5% by mass has a wavelength of 500 nm at an optical path length of 10 mm. A magnesium fluoride sol having a light transmittance of 80% or more is used as a filler component. The binder used in the coating composition is not particularly limited as long as it is compatible with sodium fluoride magnesium sol and has good film properties. For example, acrylic resin, polyester resin, urethane resin, epoxy resin, polyvinyl alcohol resin, Examples include melamine resins, gelatin and gelatin derivatives, cellulose and cellulose derivatives, polyimide resins, phenol resins, organosilicon compounds, urea resins, diallyl phthalate resins, and butyral resins.

Furthermore, in the present invention, a sodium fluoride magnesium sol having a light transmittance of 80% or more at a wavelength of 500 nm at an optical path length of 10 mm of a sol prepared with a sodium magnesium fluoride (NaF · MgF ₂ ) concentration of 5% by mass is combined with a binder. An optical member having an antireflection ability is provided by applying a coating formed from the coating composition containing the coating composition to the surface of the optical substrate.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a coating composition that can form a coating film with extremely good light transmittance and that can be applied with a coating method with a low production cost, and an optical member that has a low refractive index coating film formed from this coating composition.

  Hereinafter, embodiments of the present invention will be described in detail.

The low refractive index filler used in the coating composition of the present invention has a light transmittance at a wavelength of 500 nm at an optical path length of 10 mm of a sol prepared with a sodium magnesium fluoride (NaF · MgF ₂ ) concentration of 5% by mass of 80% or more. This is a sodium magnesium fluoride sol. The sodium magnesium fluoride sol used in the present invention is prepared by mixing an aqueous sodium fluoride solution and an aqueous magnesium salt solution at a Na / Mg molar ratio of 3.0 to form an aggregate slurry of colloidal particles of sodium magnesium fluoride. The by-product salts in the obtained aggregate slurry of colloidal particles of sodium magnesium fluoride can be removed, and the aggregate slurry of colloidal particles of sodium magnesium fluoride can be further wet pulverized.

The magnesium salt used in producing the sodium magnesium fluoride sol used in the present invention is preferably a water-soluble salt, such as magnesium chloride, magnesium nitrate, magnesium sulfate, magnesium sulfamate, magnesium acetate, magnesium formate, etc. These may be used alone or in admixture of two or more. The aqueous sodium fluoride solution and the aqueous magnesium salt solution are preferably mixed so that the Na / Mg molar ratio is 3.0. The sodium fluoride aqueous solution and the magnesium salt aqueous solution can be mixed in a temperature range of 0 to 100 ° C. using an apparatus such as a Satake type stirrer, a Faudler type stirrer, a disper, or a homogenizer. In particular, in order to obtain an average particle size of 10 to 50 nm, it is preferable to mix in a temperature range of 0 to 35 ° C. Under stirring, the addition time can be 0.1 to 10 hours. The concentration of sodium magnesium fluoride produced by mixing a sodium fluoride aqueous solution and a magnesium salt aqueous solution is 0.1 to 5.0% by mass, preferably 0.2 to 2% by mass as NaF · MgF _2. It is preferable to adjust. The produced sodium magnesium fluoride is an aggregate of colloidal particles of sodium magnesium fluoride having an average particle size of 10 to 50 nm and becomes a slurry. When the slurry is statically set, aggregates of colloidal particles of sodium magnesium fluoride settle and separate. By-product salts are formed when colloidal particles of sodium magnesium fluoride are formed. This by-product salt is derived from an anion of magnesium salt and a sodium ion derived from sodium fluoride. For example, a salt such as sodium chloride is by-produced.

  The by-product salts are then removed. As a method for removing this by-product salt, a filtration washing method such as a filter press, a membrane filtration washing method using an ultrafiltration membrane, a reverse osmosis membrane, etc., an ion exchange method, a static separation washing method, etc. can be used. A membrane filtration washing method using an ultrafiltration membrane is most preferred. Moreover, it can use together with the said membrane filtration washing | cleaning method and said other method as needed. In particular, by-product salts can be effectively removed by using a tube-type ultrafiltration membrane. Although the temperature of the process of removing salts depends on the material of the ultrafiltration membrane, it can usually be performed at 0 to 80 ° C. The higher the temperature, the higher the filtration rate and the better the cleaning properties. However, it is preferable to set the temperature to 0 to 60 ° C. because the fine colloidal particles are bonded. In order to sufficiently remove salts, it is necessary to carry out while adding pure water continuously or intermittently. Although the filtration washing time is not particularly limited, it can usually be performed in 1 to 50 hours.

  Due to the removal of by-product salts, some of the aggregates of colloidal particles of magnesium magnesium fluoride that were agglomerated due to by-product salts become smaller and become an aqueous sol, but most of the aggregates are It cannot be made into a sol only by removing salts, and remains as an aggregate. A sodium magnesium fluoride aqueous sol is obtained by wet-grinding an agglomerate slurry of colloidal particles of sodium magnesium fluoride substantially free of by-product salts using a ball mill, sand grinder, attritor, homogenizer or the like. be able to. When wet pulverizing, it is preferable to use a pulverizing medium having a particle size as small as possible. The material of the pulverizing medium is preferably glass or ceramics such as alumina, zirconia, or silica alumina.

The concentration of the sodium magnesium fluoride aqueous sol obtained by performing the above-described wet pulverization is ₂ to 50% by mass, preferably 5 to 50% by mass as NaF · MgF ₂ , but a high concentration is desirable. The temperature at which the wet pulverization is performed can be 0 to 80 ° C., but when the temperature is high, bonding of the fine colloidal particles occurs, and 0 to 40 ° C. is preferable. Moreover, although grinding | pulverization time changes with grinding | pulverization methods, it is 0.1 to 100 hours.

  The colloidal particles of the sodium magnesium fluoride aqueous sol obtained by wet pulverization can have an average particle diameter of 10 to 70 nm as observed with an electron microscope. Unpulverized or insufficiently pulverized particles can be removed by a centrifugal separation method, a static separation method, a filtration method or the like, if necessary.

  An organosol can be obtained by substituting the water of sodium magnesium fluoride aqueous sol obtained by wet pulverization with an organic solvent under reduced pressure or normal pressure by a conventional method. Examples of the organic solvent used include methanol, ethanol, isopropanol, n-propanol, dimethylformamide, dimethylacetamide, ethylene glycol, propyl cellosolve and the like, and these can be used alone or as a mixture of two or more. The temperature of the solvent replacement varies depending on the boiling point of the solvent, but it is preferable to carry out the solvent replacement at the lowest possible temperature under reduced pressure. Moreover, solvent substitution can be performed in 0.5 to 100 hours.

The concentration of the sodium magnesium fluoride organosol obtained by the solvent substitution is ₂ to 40% by mass as NaF · MgF ₂ . Moreover, the particle diameter is 10-70 nm in average particle diameter by observation with an electron microscope.

Both the sodium magnesium fluoride aqueous sol used in the present invention and the organosol obtained by solvent substitution of this sodium magnesium fluoride aqueous sol have a concentration of 5% by mass as NaF · MgF ₂ using the dispersion medium of the sol. The light transmittance in the prepared sol is 80% or more. In order to impart higher light transmittance when a low refractive index film is formed, the light transmittance is preferably 90% or more, and more preferably 95% or more. This light transmittance indicates the relative value of the transmittance of the same wavelength in a 10 mm thick sodium magnesium fluoride sol, with the transmittance of light having a wavelength of 500 nm in water having a thickness of 10 mm as 100%.

  The concentration of the sodium magnesium fluoride aqueous sol or organosol used in the present invention may be less than 2% by mass. However, when mixed with other binders, the solid content concentration is further lowered, which is not preferable. A sodium magnesium fluoride aqueous sol having a concentration exceeding 50% by mass or a sodium magnesium fluoride organosol having a concentration exceeding 40% by mass can be used, but this is not preferable because the viscosity of the sol increases.

  The binder used in the present invention is not particularly limited as long as it is compatible with sodium fluoride magnesium sol and has good coating properties. For example, acrylic resin, polyester resin, urethane resin, epoxy resin, polyvinyl alcohol resin, melamine Examples thereof include resins, gelatin and gelatin derivatives, cellulose and cellulose derivatives, polyimide resins, phenol resins, organosilicon compounds, urea resins, diallyl phthalate resins, and butyral resins.

  Acrylic resins include those shown below, and these can be used alone or in combination of two or more. Moreover, it can be used in any state of a monomer, an oligomer and a polymer. Specifically, trifluoroethyl acrylate, trifluoromethyl acrylate, phenylglycidyl acrylate, hydroxyethyl (meth) acrylate, tetrahydrofuryl acrylate, acryloylmorpholine, N-vinylpyrrolidone, N-vinyl-ε-caprolactam, neopentyl glycol ( (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, penta Erythritol (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, Reethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, nonaethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) Acrylate, nonapropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, bisphenol A di (meth) acrylate, 2-ethyl, 2-butyl-propanediol di (Meth) acrylate, 1,9-nonanediol di (meth) acrylate, hexyl 2,2-bis [4- (acryloxydiethoxy) phenyl] propane, 2,2-bis [4- (methacryloxydiethoxy) phenyl] propane, 3-phenoxy-2-propanoyl acrylate, 1,6-bis (3-acryloxy-2-hydroxypropyl) -hexyl ether, trimethylol Propane tri (meth) acrylate, glycerin tri (meth) acrylate, tris- (2-hydroxyethyl) -isocyanuric acid ester (meth) acrylate, pentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 2- Hydroxypropyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl acrylate, 2-ethylhexyl carbitol acrylate, -Carboxypolycaprolactone monoacrylate, acryloyloxyethyl acid, acrylic acid dimer, lauryl (meth) acrylate, 2-methoxyethyl acrylate, butoxyethyl acrylate, ethoxyethoxyethyl acrylate, methoxytriethylene glycol acrylate, methoxy polyethylene glycol acrylate, stearyl ( (Meth) acrylate, cyclohexyl (meth) acrylate, tetosehydrofurfuryl (meth) acrylate, N-vinyl-2-pyrrolidone, isobornyl (meth) acrylate, dicyclopentenyl acrylate, benzyl acrylate, phenylglycidyl ether epoxy acrylate, phenoxyethyl ( (Meth) acrylate, phenoxy (poly) ethylene glycol acrylate Nonylphenol ethoxylated acrylate, acryloyloxyethylphthalic acid, tribromophenyl acrylate, tribromophenol ethoxylated (meth) acrylate, methyl methacrylate, tribromophenyl methacrylate, methacryloyloxyethyl acid, methacryloyloxyethyl maleic acid, methacryloyloxy Ethyl hexahydrophthalic acid, methacryloyloxyethyl phthalic acid, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, β-carboxyethyl acrylate, N-methylol acrylate amide, N-methoxymethyl acrylate amide, N-ethoxymethyl acrylate Amide, Nn-Butoxymethylacrylamide, t-Butylacrylamides Phosphonic acid, vinyl stearylate, N-methylacrylamide, N-dimethylacrylamide, N-dimethylaminoethyl (meth) acrylate, N-dimethylaminopropylacrylamide, glycidyl methacrylate, n-butyl methacrylate, ethyl methacrylate, methacrylic acid Allyl, cetyl methacrylate, pentadecyl methacrylate, methoxypolyethylene glycol (meth) acrylate, diethylaminoethyl (meth) acrylate, methacryloyloxyethyl succinic acid, hexanediol diacrylate, neopentyl glycol diacrylate, triethylene glycol diacrylate, polyethylene Glycol diacrylate, polypropylene glycol meldiacrylate, hydroxypivalate ester Opentyl, pentaerythritol diacrylate monostearate, glycol diacrylate, 2-hydroxyethyl methacryloyl phosphate, bisphenol A ethylene glycol adduct acrylate, bisphenol F ethylene glycol adduct acrylate, tricyclodecane methanol diacrylate, trishydroxyethyl isocyanate Nurate diacrylate, 2-hydroxy-1acryloxy-3-methacryloxypropane, trimethylolpropane triacrylate, trimethylolpropane ethylene glycol adduct triacrylate, trimethylolpropane propylene glycol adduct triacrylate, pentaerythritol triacrylate, trisacryloyl Oxyethyl phosphate, Tris Droxyethyl isocyanurate triacrylate, modified ε-caprolactone triacrylate, trimethylolpropane ethoxytriacrylate, glycerin propylene glycol adduct triacrylate, pentaerythritol tetraacrylate, pentaerythritol ethylene glycol adduct tetraacrylate, ditrimethylolpropane tetraacrylate, Examples include dipentaerythritol hexa (penta) acrylate, dipentaerythritol monohydroxypentaacrylate, and epoxide acrylate.

  As the polyester resin, linear polyester having a dicarboxylic acid component and a glycol component as constituent components can be used. Examples of the dicarboxylic acid component and the glycol component are shown below. These may be used alone or in combination of two or more. Dicarboxylic acid component: terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4-diphenyldicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, phenylindanedicarboxylic acid and dimer acid . Glycol component: ethylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylylene glycol, dimethylolpropionic acid, glycerin, tri Methylolpropane, poly (ethyleneoxy) glycol, poly (tetramethyleneoxy) glycol, alkylene oxide adduct of bisphenol A and alkylene oxide adduct of hydrogenated bisphenol A.

  As the urethane resin, those obtained by polyaddition reaction of polyisocyanate and active hydrogen-containing compound can be used. Examples of polyisocyanates and active hydrogen-containing compounds are shown below. These can be used individually or in mixture of 2 or more types. Polyisocyanate: ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate (2,6-diisocyanate) Isocyanatomethyl caproate), bis (2-isocyanatoethyl) fumarate, bis (2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6-diisocyanatohexanoate, isophorone diisocyanate (IPDI), Dicyclohexylmethane-4,4′-diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, bis (2-isocyana Ethyl) -4-cyclohexene-1,2-dicarboxylate, 2,5- and / or 2,6-norbornane diisocyanate, m- and / or p-xylylene diisocyanate, α, α, α ′, α′- Tetramethylxylylene diisocyanate and polyisocyanate modified products include modified MDI (urethane modified MDI, carbodiimide modified MDI, trihydrocarbyl phosphate modified MDI), urethane modified TDI, burette modified HDI, isocyanurate modified HDI, isocyanurate modified IPDI. Modified products of polyisocyanate, etc. and mixtures of two or more thereof. Active hydrogen-containing compound: dihydric alcohol (ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol), diol having a branched chain (propylene Glycol, neopentyl glycol, 3-methyl 1,5-pentanediol, 2,2-diethyl-1,3-propanediol, 1,2-, 1,3- or 2,3-butanediol), a cyclic group Diol (1,4-bis (hydroxymethyl) cyclohexane, m- or p-xylylene glycol), dihydric phenol (bisphenol A), polyhydric alcohol (glycerin, trimethylolpropane, pentaerythritol, sorbitol), saccharides and Its derivatives (sucrose, methyl glucoside), Aliphatic diamine (ethylenediamine, hexamethylenediamine, etc.), alicyclic diamine (4,4′-diamino-3,3′-dimethyldicyclohexylmethane, 4,4′-diamino-3,3′-dimethyldicyclohexyl, diaminocyclohexane , Isophoronediamine), aromatic diamine (diethyltoluenediamine), araliphatic diamine (xylylenediamine, α, α, α ', α'-tetramethylxylylenediamine), heterocyclic diamine (piperidine), polyfunctional amine (Diethylenetriamine, triethylenetetramine), polymer polyol (polyester polyol, polyether polyol), aliphatic polycarboxylic (succinic acid, glutaric acid, maleic acid, fumaric acid, adipic acid, azelaic acid, sebacic acid, hexahydrophthalic acid ), Fragrance Polycarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid, tetrabromophthalic acid, tetrachlorophthalic acid, trimellitic acid, pyromellitic acid), maleic anhydride, phthalic anhydride, dimethyl terephthalate, lactone monomers (γ- A structure in which butyrolactone, ε-caprolactone, γ-valerolactone and a compound alkylene oxide having two or more active hydrogen atoms are added.

  Examples of the epoxy resin include various liquid epoxy resins such as bisphenol A type, bisphenol F type, hydrogenated bisphenol A type, bisphenol AF type, phenol novolac type, and derivatives thereof, and liquid epoxy resins derived from polyhydric alcohol and epichlorohydrin, and Various glycidyl-type liquid epoxy resins such as derivatives thereof, glycidylamine-type, hydantoin-type, aminophenol-type, aniline-type, and toluidine-type and derivatives thereof can be used.

  As the polyvinyl alcohol-based resin, those obtained by saponifying a polyvinyl ester-based polymer obtained by radical polymerization of a vinyl ester-based monomer such as vinyl acetate can be used. Examples of the polyvinyl ester polymer are shown below. These can be used individually or in mixture of 2 or more types. Polyvinyl ester polymers: vinyl esters such as vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate and vinyl versatate. The polyvinyl ester polymer may be a copolymer obtained by copolymerizing a comonomer that can be copolymerized with the above vinyl ester monomers. Examples of the comonomer include olefins such as ethylene, propylene, 1-butene, and isobutene, acrylic acid, and Its salts, methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate , Acrylic esters such as octadecyl acrylate, methacrylic acid and salts thereof, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, methacrylic acid T-butyl acid, methacrylic acid -Methacrylic acid esters such as ethylhexyl, dodecyl methacrylate, octadecyl methacrylate, acrylamide, hydroxyalkyl, N-methylacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, diacetone acrylamide, acrylamide propanesulfonic acid and salts thereof Acrylamide derivatives such as acrylamidopropyldimethylamine and salts thereof, or quaternary salts thereof, N-methylolacrylamide and derivatives thereof, methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidepropanesulfonic acid and salts thereof Methacrylamide such as methacrylamidopropyldimethylamine and salts thereof, or quaternary salts thereof, N-methylol methacrylamide and derivatives thereof Conductors, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, vinyl ethers such as stearyl vinyl ether, acrylonitrile, methacrylonitrile, etc. Nitriles, vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, allyl compounds such as allyl acetate and allyl chloride, maleic acid and its salts, or esters thereof, vinylsilyl compounds such as vinyltrimethoxysilane And isopropenyl acetate.

  As the melamine resin, methylated melamine resin, butylated melamine resin, methylbutyl mixed melamine resin and the like can be used.

  As gelatin and gelatin derivatives, phthalated gelatin, succinated gelatin, trimellit gelatin, pyromellitic gelatin, esterified gelatin, amidated gelatin, formylated gelatin and the like can be used.

  Examples of cellulose and cellulose derivatives include diacetyl cellulose, triacetyl cellulose, hydroxypropyl cellulose, triacetyl cellulose, diacetyl cellulose, acetyl cellulose, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate phthalate, cellulose acetate trimethytate, nitric acid Cellulose or the like can be used.

As an organosilicon compound, the silicon compound containing the following A component and / or B component is mentioned, for example.
A component: General formula (I)
(R ¹ ) _a (R ³ ) _b Si (OR ² ) _{4− (a + b)} (I)
(Wherein R ¹ and R ³ are each selected from the group consisting of alkyl, alkenyl, aryl, acyl, halogen, glycidoxy, epoxy, amino, phenyl, mercapto, methacryloxy and cyano groups. R ² represents an organic group selected from the group consisting of an alkyl group having 1 to 8 carbon atoms, an alkoxy group, an acyl group, and a phenyl group, and a and b are integers of 0 or 1. .) Or an hydrolyzate thereof.
Component B: General formula (II)
{(OX) _3−a Si (R ⁴ )} ₂ Y (II)
(Here, R ⁴ represents an organic group having 1 to 5 carbon atoms, X represents an alkyl group having 1 to 4 carbon atoms or an acyl group having 1 to 4 carbon atoms, and Y represents an organic group having 2 to 20 carbon atoms. And a is an integer of 0 or 1.) or an hydrolyzate thereof.
A component is shown by the general formula (I) mentioned above. Examples of specific organosilicon compounds or hydrolysates thereof: methyl silicate, ethyl silicate, n-propyl silicate, iso-propyl silicate, n-butyl silicate, tetraacetoxysilane, methyltrimethoxysilane, methyltripropoxysilane, Methyltriacetyloxysilane, methyltributoxysilane, methyltripropoxysilane, methyltriamyloxysilane, methyltriphenoxysilane, methyltribenzyloxysilane, methyltriphenethyloxysilane, glucidoxymethyltrimethoxysilane, glycidoxy Methyltrimethoxysilane, α-glycidoxyethyltrimethoxysilane, α-glycidoxytriethyoxysilane, β-glycidoxytrimethoxysilane, β-glycidoxyethyltriethoxy Run, α-glycidoxypropyltrimethoxysilane, α-glycidoxypropyltriethoxysilane, β-glycidoxypropyltrimethoxysilane, β-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxy Silane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltripropoxysilane, γ-glycidoxypropyltributoxysilane, γ-glycidoxypropyltriphenoxysilane, α-glycidoxybutyltrimethoxy Silane, α-glycidoxybutyltriethoxysilane, β-glycidoxybutyltriethoxysilane, γ-glycidoxybutyltrimethoxysilane, γ-glycidoxybutyltriethoxysilane, δ-glycidoxybutyltrimethoxy Silane, δ-glycidoxib Rutriethoxysilane, (3,4-epoxycyclohexyl) methyltrimethoxysilane, (3,4-epoxycyclohexyl) methyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3 4-epoxycyclohexyl) ethyltriethoxysilane, β- (3,4-epoxycyclohexyl) ethyltripropoxysilane, β- (3,4-epoxycyclohexyl) ethyltributoxysilane, β- (3,4-epoxycyclohexyl) Ethyltriphenoxysilane, γ- (3,4-epoxycyclohexyl) propyltrimethoxysilane, γ- (3,4-epoxycyclohexyl) propyltriethoxysilane, δ- (3,4-epoxycyclohexyl) butyltrimethoxysilane, δ- (3 4-epoxycyclohexyl) butyltriethoxysilane, glycidoxymethylmethyldimethoxysilane, glycidoxymethylmethyldiethoxysilane, α-glycidoxyethylmethyldimethoxysilane, α-glycidoxyethylmethyldiethoxysilane, β- Glycidoxyethylmethyldimethoxysilane, β-glycidoxyethylethyldimethoxysilane, α-glycidoxypropylmethyldimethoxysilane, α-glycidoxypropylmethyldiethoxysilane, β-glycidoxypropylmethyldimethoxysilane, β -Glycidoxypropylethyldimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldipropoxysilane, γ-glycidoxy Cypropylmethyldibutoxysilane, γ-glycidoxypropylmethyldiphenoxysilane, γ-glycidoxypropylethyldiethoxysilane, γ-glycidoxypropylethyldiethoxysilane, γ-glycidoxypropylvinylmethoxysilane, γ-glycidoxypropyl vinylethoxysilane, γ-glycidoxypropyl vinylphenylmethoxysilane, γ-glycidoxypropylvinylphenylethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxy Silane, vinyltrimethoxyethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxy Silane, γ-chloropropyltriacetoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, β- Cyanoethyltriethoxysilane, chloromethyltrimethoxysilane, chloromethyltriethoxysilane, N- (β-aminoethyl) γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) γ-aminopropylmethyldimethoxysilane, γ -Aminopropylmethyltrimethoxysilane, N- (β-aminoethyl) γ-aminopropyltriethoxysilane, N- (β-aminoethyl) γ-aminopropylmethyldiethoxysilane, dimethyldimethoxysilane, phenylmethyldimethyl Xysilane, dimethyldiethoxysilane, phenylmethyldiethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropylmethyldiethoxysilane, dimethyldiacetoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyl Diethoxysilane, γ-mercaptopropylmethyldimethoxysilane, γ-mercaptomethyldiethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane and hydrolysates thereof.

  The B component is represented by the general formula (II) described above. Examples of specific organosilicon compounds or hydrolysates thereof: methylene bismethyldimethoxysilane, ethylene bisethyldimethoxysilane, propylene bisethyldiethoxysilane, butylene bismethyldiethoxysilane, and hydrolysates thereof.

  The A component and / or the B component organosilicon compound can be used alone or as a mixture of the A component and the B component alone. It is also possible to use two or more types of A component and two or more types of B component. Hydrolysis of the organosilicon compound of component A and / or component B is carried out by adding an acidic aqueous solution such as aqueous hydrochloric acid, sulfuric acid, or aqueous acetic acid to the organosilicon compound of component A and / or B. Is done.

  As the organosilicon compound, modified silicone varnishes such as silicone varnish, silicone alkyd varnish, silicone epoxy varnish, silicone acrylic varnish, and silicone polyester varnish can be used in addition to the above silicon compound. These can be used alone or in admixture of two or more.

  As the diallyl phthalate resin, diallyl phthalate, diallyl isophthalate and diallyl terephthalate can be used.

  Examples of the butyral resin include polyvinyl butyral.

  The coating composition of the present invention contains the binder and sodium magnesium fluoride sol, and if necessary, a solvent for preparing a coating liquid, a polymerization initiator, a curing agent, a crosslinking agent, an ultraviolet blocking agent, You may mix | blend a ultraviolet absorber, a surface adjuster (leveling agent), or another component.

  For example, when the binder has an ionizing radiation curable group, a radical photopolymerization initiator is used. Examples of radical photopolymerization initiators include acetophenones, benzophenones, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds, thiuram compounds, fluoro An amine compound or the like is used. More specifically, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, benzyldimethylketone, 1- (4-dodecyl) Phenyl) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane Examples thereof include -1-one and benzophenone. Among these, 1-hydroxy-cyclohexyl-phenyl-ketone and 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one can undergo polymerization reaction by irradiation with ionizing radiation even in a small amount. Preferred for starting and promoting. These can be used either alone or in combination. These are also present in commercial products, and 1-hydroxy-cyclohexyl-phenyl-ketone is available from Ciba Specialty Chemicals under the trade name Irgacure 184.

  When using a radical photopolymerization initiator, it is desirable to blend the radical photopolymerization initiator in a proportion of usually 1 to 30 parts by mass with respect to the binder component.

  A hardening | curing agent is mix | blended in order to accelerate | stimulate the thermosetting reaction of the thermosetting polar group of a binder. When the thermosetting polar group is a hydroxyl group, a compound having a basic group such as methylolmelamine or a compound having a hydrolyzable group that generates a hydroxyl group by hydrolysis of a metal alkoxide or the like is usually used as a curing agent. .

  When the thermosetting polar group of the binder component is an epoxy group, a polyvalent carboxylic acid anhydride or a polyvalent carboxylic acid is usually used as a curing agent in the coating composition. Specific examples of the polyvalent carboxylic acid anhydride include phthalic anhydride, itaconic anhydride, succinic anhydride, citraconic anhydride, dodecenyl succinic anhydride, tricarballylic anhydride, maleic anhydride, hexahydrophthalic anhydride, dimethyltetrahydro anhydride Aliphatic or alicyclic dicarboxylic anhydrides such as phthalic acid, hymic anhydride, and nadic anhydride; Fats such as 1,2,3,4-butanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride Polyhydric carboxylic acid dianhydrides; aromatic polycarboxylic anhydrides such as pyromellitic anhydride, trimellitic anhydride, and benzophenone tetracarboxylic anhydride; ester groups such as ethylene glycol bistrimellitate and glycerin tristrimitate Containing acid anhydrides, particularly preferably aromatic polycarboxylic acids Anhydride can be mentioned. Moreover, the epoxy resin hardening | curing agent which consists of a commercially available carboxylic acid anhydride can also be used suitably. Specific examples of the polycarboxylic acid include aliphatic polycarboxylic acids such as succinic acid, glutaric acid, adipic acid, butanetetracarboxylic acid, maleic acid and itaconic acid; hexahydrophthalic acid, 1,2-cyclohexane Aliphatic polycarboxylic acids such as dicarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid and cyclopentanetetracarboxylic acid, and phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, trimellitic acid, 1,4,5 , 8-Naphthalenetetracarboxylic acid, benzophenonetetracarboxylic acid, and other aromatic polyvalent carboxylic acids, preferably aromatic polyvalent carboxylic acids.

  When using a hardening | curing agent, a hardening | curing agent is normally mix | blended in the ratio of 0.05-30.0 mass part with respect to a binder component.

  The solvent used in the coating composition of the present invention is not particularly limited, and various organic solvents, for example, alcohols such as isopropyl alcohol, methanol, ethanol, butanol, ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl acetate, Esters such as butyl acetate, aromatic hydrocarbons such as toluene and xylene, and mixtures thereof can be used.

  The coating composition of the present invention can be applied on an optical substrate by various known methods. Examples of the method include spin coating, dipping, spraying, slide coating, bar coating, roll coater, meniscus coater, flexographic printing, screen printing, and bead coater.

  The optical member of the present invention can be obtained by applying the coating composition of the present invention to the surface of an optical substrate to form a film. Since this coating contains colloidal particles of sodium magnesium fluoride having a low refractive index, the refractive index is very low, the transparency is excellent, and the mass productivity is also excellent. This coating can be particularly suitably used as an optical thin film that requires a low refractive index, particularly as a low refractive index layer of an antireflection film.

  For the antireflection film, a single layer configuration in which a low refractive index layer having a low refractive index is provided on the display surface, or a plurality of medium to high refractive index layers on the display surface in order to further improve the antireflection effect. There is a multilayer structure in which a low refractive index layer for reducing the refractive index of the outermost surface is provided on the middle to high refractive index layer. The optical member of the present invention may be used as an antireflection film by forming a film obtained by applying the coating composition of the present invention directly on the surface of the optical substrate, or the optical substrate and the coating composition of the present invention. You may form the antireflection film which provided multiple layers of medium-high refractive index layers between the films obtained by apply | coating.

  The optical substrate on which the coating composition of the present invention is coated is not particularly limited. For example, glass or triacetate cellulose (TAC), polyethylene terephthalate (PET), diacetyl cellulose, acetate butyrate cellulose, polyethersulfone, acrylic resin, polyurethane resin, polyester, polycarbonate, polysulfone, polyether, trimethylpentene, poly Examples thereof include films formed of various resins such as ether ketone and (meth) acrylonitrile.

  The optical member of the present invention is a liquid crystal display (LCD), a cathode ray tube (CRT), a plasma display panel (PDP), an electroluminescence display (as an optical member having a low refractive index coating layer and having antireflection ability, ELD) is suitably used as a material for a display surface of an image display device.

Reference Example (a) Step: 2268 g of sodium fluoride (NaF, reagent grade, manufactured by Kanto Chemical Co., Inc.) was dissolved in 100 liters of pure water to prepare 102.3 kg of sodium fluoride aqueous solution. The concentration of sodium fluoride in this aqueous solution was 2.22% by mass. On the other hand, 3654 g of magnesium chloride (MgCl ₂ · 6H ₂ O, reagent grade, manufactured by Kosou Chemical Co., Ltd.) was dissolved in 100 liters of pure water to prepare 103.7 kg of magnesium chloride aqueous solution. The concentration of magnesium chloride (MgCl ₂ ) in this aqueous solution was 1.65% by mass. 102.3 kg of the aqueous sodium fluoride solution was charged into a 300 liter container, and 103.7 kg of the aqueous magnesium chloride solution was added over 30 minutes at room temperature while stirring vigorously using a disper. A slurry of 206 kg of sodium magnesium fluoride colloidal particles was obtained. The reaction formula is as follows.
3NaF + MgCl ₂ → NaF · MgF ₂ + 2NaCl
The sodium fluoride and magnesium chloride had a Na / Mg molar ratio of 3.0. The obtained slurry of colloidal particles of sodium magnesium fluoride is partly sol, but settles by settling to form aggregates of colloidal particles of sodium magnesium fluoride. The concentration of sodium magnesium fluoride in this slurry was 0.91% by mass.

(B) Process: Using a tube-type ultrafiltration device [UF (PS-150), manufactured by Mitsubishi Rayon Engineering Co., Ltd.], 206 kg of the aggregate slurry of colloidal particles of sodium magnesium fluoride obtained in the (a) process. Then, filtration and washing were performed while adding 420 kg of pure water at the same rate as the ultrafiltration rate. The liquid temperature of the slurry during filtration washing was 25 ° C., and the filtration time was 15.5 hours. The solid content concentration during filtration washing was about 3.0% by mass as NaF · MgF ₂ . After filtration and washing, the solution was concentrated by the same ultrafiltration device to obtain 6170 g of an aggregate slurry of colloidal particles of sodium magnesium fluoride substantially free of salts. The agglomerate slurry of colloidal particles of sodium magnesium fluoride obtained in step (b) has a sodium magnesium fluoride concentration (NaF · MgF ₂ ) concentration of 28.0% by mass and an electrical conductivity of 870 μs / cm. A part of the aggregates settled. The yield of sodium magnesium fluoride was approximately 92%.

Step (c): 500 g of ceramic grinding beads were added to 670 g of colloidal particles of sodium magnesium fluoride colloidal particles substantially free of salts obtained in step (b), and a batch type sand grinder (rotation speed 2000 r) was added. Pm, kept at room temperature by cooling) to obtain a sodium magnesium fluoride aqueous sol. When the sol was recovered after pulverization, the pulverization beads were washed with pure water, so that the mass of the obtained sodium magnesium fluoride aqueous sol was 1440 g. This sodium magnesium fluoride aqueous sol had a specific gravity of 1.100, a pH of 7.13, a viscosity of 3.2 mPa · s, a sodium magnesium fluoride (NaF · MgF ₂ ) concentration of 13.0% by mass, and an electric conductivity of 410 μs / cm. .

This sodium magnesium fluoride aqueous sol was replaced with methanol under reduced pressure using a rotary evaporator to obtain a sodium fluoride magnesium methanol sol, and then replaced with isopropanol in the same manner to obtain a sodium fluoride magnesium isopropanol sol. . The obtained sodium fluoride magnesium isopropanol sol had a specific gravity of 0.84, a pH of 8.4 when diluted to 1 + 1 with pure water, a viscosity of 7.8 mPa · s, and a sodium magnesium fluoride (NaF · MgF ₂ ) concentration of 10. It was 5 mass%. In addition, this sodium magnesium fluoride isopropanol sol was prepared by using a spectroscopic color difference meter TC-1800MK-II (manufactured by Tokyo Denshoku Co., Ltd.) to prepare a sodium magnesium fluoride (NaF · MgF ₂ ) concentration of 5% by mass. As a result of measuring the light transmittance, the light transmittance at a wavelength of 500 nm at an optical path length of 10 mm was 99.0%, the average particle diameter was 40 nm, and the particle diameter by dynamic light scattering was 80 nm as observed with an electron microscope. It was.

Example 1
0.45 g of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.) and Irgacure 184 (manufactured by Ciba Specialty Chemicals Co., Ltd.) are added to 10.5 g of sodium fluoride magnesium isopropanol sol obtained in the reference example. 0.02 g and 19.0 g of isopropanol were added to prepare a coating composition containing sodium magnesium fluoride. The obtained coating composition was applied on a silicon wafer cut to 5 cm × 5 cm using a spin coater, and then irradiated with ultraviolet rays to produce a low refractive index film. As a result of measuring the obtained low refractive index film with an ellipsometer (Fibravo MARY-102), the refractive index was 1.4799 and the film thickness was 892 mm.

Example 2
To 7.5 g of sodium fluoride magnesium isopropanol sol obtained in the reference example, 0.71 g of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.) and Irgacure 184 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 0.04 g and 15.0 g of isopropanol were added to prepare a coating composition containing sodium magnesium fluoride. The obtained coating composition was applied on a silicon wafer cut to 5 cm × 5 cm using a spin coater, and then irradiated with ultraviolet rays to produce a low refractive index film. As a result of measuring the obtained low refractive index film with an ellipsometer (Fibravo MARY-102), the refractive index was 1.4361 and the film thickness was 993 mm.

Example 3
To 4.5 g of sodium fluoride magnesium isopropanol sol obtained in the reference example, 1.0 g of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.) and Irgacure 184 (manufactured by Ciba Specialty Chemicals Co., Ltd.) 0.05 g and 24.45 g of isopropanol were added to prepare a coating composition containing sodium magnesium fluoride. The obtained coating composition was applied on a silicon wafer cut to 5 cm × 5 cm using a spin coater, and then irradiated with ultraviolet rays to produce a low refractive index film. As a result of measuring the obtained low refractive index film with an ellipsometer (Fibravo MARY-102), the refractive index was 1.3838 and the film thickness was 991 mm.

Comparative Example 1
Silica isopropanol sol (trade name IPA-ST; manufactured by Nissan Chemical Industries, Ltd.), 0.95 g of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.) and Irgacure 184 (Ciba Specialty Chemicals) 0.05 g and 35.7 g of isopropanol were added to prepare a coating composition containing silica. The obtained coating composition was applied on a silicon wafer cut to 5 cm × 5 cm using a spin coater, and then irradiated with ultraviolet rays to produce a low refractive index film. The obtained low refractive index film was measured with an ellipsometer (Fibravo MARY-102). As a result, the refractive index was 1.4917 and the film thickness was 926 mm.

Comparative Example 2
To 7.5 g of magnesium fluoride isopropanol sol (MFS-10P: manufactured by Nissan Chemical Industries, Ltd.), 0.71 g of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.) and Irgacure 184 (Ciba Specialty Chemicals) 0.04 g and 15.0 g of isopropanol were added to prepare a coating composition containing magnesium fluoride. The obtained coating composition was applied on a silicon wafer cut to 5 cm × 5 cm using a spin coater, and then irradiated with ultraviolet rays to produce a low refractive index film. As a result of measuring the obtained low refractive index film with an ellipsometer (Fibravo MARY-102), the refractive index was 1.4536 and the film thickness was 967 mm.

  The coating composition of the present invention can form a coating film with extremely good light transmittance on an optical substrate, and can be applied by a coating method with low production cost. The optical member of the present invention is a liquid crystal display (LCD), a cathode ray tube (CRT), a plasma display panel (PDP), an electroluminescence display, in particular, as an optical member having a low refractive index coating layer and having antireflection performance. It is suitably used as a material for the display surface of an image display device such as (ELD).

Claims (3)

A coating composition comprising a sodium magnesium fluoride sol having a light transmittance of 80% or more at a wavelength of 500 nm at an optical path length of 10 mm of a sol prepared with a sodium magnesium fluoride (NaF · MgF ₂ ) concentration of 5% by mass, and a binder. The binder is acrylic resin, polyester resin, urethane resin, epoxy resin, polyvinyl alcohol resin, melamine resin, gelatin and gelatin derivative, cellulose and cellulose derivative, polyimide resin, phenol resin, organosilicon compound, urea resin, diallyl phthalate resin and The coating composition according to claim 1, which is at least one selected from the group consisting of butyral resins. The optical member which has a film formed from the coating composition of Claim 1 or Claim 2 on the optical base material surface.