KR20080095773A - Coating composition and optical member - Google Patents

Abstract

A coating composition and an optical member having the low refractive film formed with the coating composition are provided to form the film having excellent light transmittance and to apply a coating method with production costs. A coating composition a binder and a sodium fluoride magnesium sol in which light transmittance of wavelength 500nm at the optic path length 10mm is 80% or more, wherein the sol is prepared to become 5 mass % of the sodium fluoride magnesium(NaF.MgF2) concentration. The optical member formed with a low refractive film is obtained by coating an optical member with the coating composition.

Description

Coating composition and optical member {COATING COMPOSITION AND OPTICAL MEMBER}

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

Generally, on the image display surface of a lens, a cathode ray tube, a liquid crystal display, etc., antireflective processing is performed in order to reduce reflection of external light, such as sunlight and electric light, and to increase the passage of light. Background Art Conventionally, a phenomenon in which reflectance is lowered by covering the surface of a transparent object with a transparent film having a low refractive index is known. It is possible to improve the visibility by providing an antireflection film utilizing 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 small refractive index is provided on the display surface, or a plurality of medium-high refractive index layers are provided on the display surface in order to further improve the antireflection effect. There is a multilayer structure provided with a low refractive index layer for reducing the refractive index of the outermost surface.

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

The transparent film obtained by the vapor phase method can form a high quality transparent thin film, but since the suppression of the atmosphere under high vacuum is required, and a special heating device or an ion generating accelerator is required, the manufacturing apparatus is complicated and large, and consequently large. There is a problem that the manufacturing cost is high. In addition, the gas phase method is difficult to make the transparent thin film large in area.

On the other hand, in the case of spraying in the coating method, there are problems such as poor utilization efficiency of the coating liquid and difficulty in controlling the film forming conditions. However, the roll coating method, the gravure coating method, the slide coating method, the deposition method, the screen printing method, etc. The use efficiency of coating liquid is favorable in the case of etc., and is advantageous in terms of mass production and equipment cost.

As a transparent film obtained by the coating method, a coating composition containing silica or magnesium fluoride having a low refractive index as a filler is applied to the surface of the optical base material and dried, or a coating composition containing silica or magnesium fluoride is applied to the surface of the optical base material. It is known to harden | cure by UV irradiation etc. after apply | coating and drying to form a low refractive index layer. The low refractive index of silica is 1.45, the magnesium fluoride is 1.378-1.390, and in order to obtain a high-efficiency coating as a low refractive index coating, it is necessary to select a filler with a lower refractive index as the material.

Sodium fluoride is known as a material of a metal fluoride having a refractive index lower than that of 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, which is lower than that of magnesium fluoride (1.378-1.390), but magnesium fluoride is soluble in water. It is quite difficult to form fine particles or sol.

As a material of water-insoluble metal fluoride, Japanese Patent Application Laid-Open No. 7-69620 (Patent Document 1) proposes a sol made of colloidal particles of sodium magnesium fluoride (NaF · MgF ₂ ) having an average particle diameter of 10-100 nm. 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 more useful as a material having a lower refractive index than silica or magnesium fluoride.

[Patent Document 1] Japanese Patent Laid-Open No. 7-69620

[Non-Patent Document 1] Handbook of Chemistry and Physics (1970-1971, 51st edition)

[Non-Patent Document 2] Physics and Chemistry of Minerals 20, 419-424 (1993)

The low refractive index film used for the antireflection layer of the optical member requires high light transmittance while preventing external light reflection. Since sodium magnesium fluoride of patent document 1 has a low light transmittance, when the low refractive index film was used, there existed a subject that a sufficiently high light transmittance was not obtained.

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

In order to solve the above problems, in the present invention, as a coating composition for obtaining a low refractive index film, a light transmittance of 500 nm 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 80. Magnesium sodium fluoride of not less than% is used as the filler component.

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

Further, from the the invention, the coating composition comprising a sodium magnesium fluoride (NaF · MgF ₂₎ sodium fluoride or higher the sheet path of the sol was adjusted to 5 wt% light transmittance at wavelength of 500nm in a 10mm 80% strength magnesium sol and a binder The formed film is provided on the surface of the optical base to provide an optical member having an antireflection capability.

According to the present invention, it is possible to provide a coating having extremely good light transmittance, and to provide an optical member having a coating composition capable of applying a coating method having a low production cost and a low refractive index coating formed from the coating composition.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail.

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

The magnesium salt used in the preparation of the sodium magnesium fluoride sol used in the present invention is preferably a salt that is soluble in water. For example, magnesium chloride, magnesium nitrate, magnesium sulfate, magnesium sulfamate, magnesium acetate, magnesium formate These can be mentioned, These can be used individually or in mixture of 2 or more types. It is preferable to mix sodium fluoride aqueous solution and magnesium salt aqueous solution so that Na / Mg molar ratio may be 3.0. The aqueous sodium fluoride solution and the aqueous magnesium salt solution can be mixed in a temperature range of 0-100 ° C using apparatuses such as a Satake stirrer, a Pfaudler stirrer, a dispa, and a homogenizer. In particular, in order to make an average particle diameter of 10-50 nm, it is preferable to mix in the temperature range of 0-35 degreeC. Under stirring, the addition time can be performed at 0.1-10 hours. The concentration of sodium magnesium fluoride produced by mixing the aqueous sodium fluoride solution and the aqueous magnesium salt solution is preferably adjusted to 0.1-5.0 mass%, preferably 0.2-2 mass% as NaF.MgF ₂ . The produced sodium magnesium fluoride is an aggregate of colloidal particles of sodium magnesium fluoride having an average particle diameter of 10-50 nm, and becomes a slurry. In this slurry, aggregates of colloidal particles of sodium magnesium fluoride precipitate and separate. By-product salts are produced when colloidal particles of sodium magnesium fluoride are produced. The by-product salts are caused by the anion of magnesium salts and sodium ions resulting from sodium fluoride, and for example, by-products such as sodium chloride are byproducts.

Next, the by-product salts are removed. As a method for removing the by-product salts, a filtration cleaning method such as a filter press, a membrane filtration cleaning method using an ultrafiltration membrane, a salt permeation membrane, etc., an ion exchange method, a corrective separation cleaning method, and the like can be used, but a membrane filtration cleaning method using an ultrafiltration membrane is most preferred. . Moreover, the membrane filtration cleaning method and the said other method can be used together as needed. In particular, by-product ultrafiltration membranes can be used to effectively remove by-product salts. Although the temperature of the process of removing a salt is based also on the material of an ultrafiltration membrane, it can carry out normally at 0-80 degreeC. The higher the temperature, the higher the filtration rate and the better the washability. However, the temperature is preferably 0-60 ° C. in order for the microcolloid particles to be bound. In order to remove salt sufficiently, it is necessary to carry out adding pure water continuously or intermittently. The filtration washing time is not particularly limited, but can usually be performed at 1-50 hours.

By removing the by-product salts, in the aggregates of the colloidal particles of sodium magnesium fluoride, some of the aggregates aggregated by the by-product salts become small and form an aqueous sol. However, most of the aggregates cannot be sol by salt removal alone and remain as aggregates. An aqueous sodium magnesium fluoride sol can be obtained by wet milling an aggregate slurry of colloidal particles of sodium magnesium fluoride substantially free of by-product salts using a device such as a ball mill, sand grinder, atrider, homogenizer, or the like. have. In the case of wet grinding, it is preferable to use a grinding media having a particle size as small as possible, and the material of the grinding media is glass or ceramics such as alumina, zirconia and silica alumina.

The concentration of the aqueous sodium magnesium fluoride sol obtained by performing the wet grinding is 2-50% by mass, preferably 5-50% by mass, as NaF.MgF ₂ , but is preferably high. Although the temperature at the time of wet grinding can be performed at 0-80 degreeC, 0-40 degreeC is preferable, since the coupling | bonding of micro colloidal particle arises when temperature becomes high. The grinding time is 0.1-100 hours, depending on the grinding method.

The colloidal particles of the sodium magnesium fluoride aqueous sol obtained by wet grinding can be observed by an electron microscope, and the average particle diameter can be 10-70 nm. Fine grinding or grinding insufficient particles can be removed by centrifugation, correction separation, filtration or the like as necessary.

The organosol can be obtained by substituting the water of the sodium magnesium fluoride aqueous sol obtained by wet grinding with an organic solvent under reduced pressure or normal pressure according to 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 may be used alone or as a mixture of two or more thereof. Although the temperature of the solvent substitution differs depending on the boiling point of the solvent, it is preferable to carry out at a lower temperature as possible under reduced pressure. In addition, solvent substitution can be performed in 0.5-100 hours.

The concentration of the sodium magnesium fluoride organosol obtained by the solvent substitution is 2-40 mass% as NaF.MgF ₂ . In addition, this particle diameter is observed by the electron microscope and an average particle diameter is 10-70 nm.

The organosol obtained by solvent-substituting the sodium magnesium fluoride aqueous sol and its sodium magnesium fluoride aqueous sol used in the present invention may be any of sol prepared at a concentration of 5% by mass as NaF.MgF ₂ using a dispersion medium of the sol. The light transmittance is 80% or more. In order to provide high light transmittance by using a low refractive index film, the light transmittance is preferably 90% or more, more preferably 95% or more. This light transmittance makes the transmittance | permeability of the light of wavelength 500nm in water of 10mm thickness 100%, and shows the relative value of the transmittance | permeability of the same wavelength in sodium magnesium fluoride sol of thickness 10mm.

The concentration of the sodium magnesium fluoride aqueous sol or organo sol used in the present invention may be less than 2% by mass, but when used in combination with other binders, the concentration of solids is further lowered. In addition, an aqueous sodium magnesium fluoride sol having a concentration exceeding 50% by mass or a sodium magnesium fluoride organo sol having a concentration exceeding 40% by mass may be used. However, the viscosity of the sol increases, which is not preferable. The binder used in the present invention is not particularly limited as long as it is compatible with sodium magnesium fluoride sol and has good coating properties. Examples of the binder include acrylic resins, polyester resins, urethane resins, epoxy resins, polyvinyl alcohol resins, melamine resins, Gelatin resins and gelatin derivatives, cellulose and cellulose derivatives, polyimide resins, phenol resins, organosilicon compounds, urea resins, diallyl phthalate resins, butyral resins and the like.

As an acrylic resin, there exist some shown below and these can be used individually or in mixture of 2 or more types. Moreover, it can use in any state of a monomer, an oligomer, and a polymer. Specifically, trifluoroethyl acrylate, trifluoromethyl acrylate, phenylglycidyl acrylate, hydroxyethyl (meth) acrylate, tetrahydrofuryl acrylate, acryloyl morpholine, N-vinyl pyrrole Lolidon, N-vinyl-ε-caprolactam, neopentyl glycol (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimetholpropane (meth) acrylate, ditrimetholpropane tetra (Meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate , Triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, nonaethylene glycol di (meth) acrylate, polyethylene glycol di (meth) arc Relate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, nonapropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, hydroxy pivalate neopentyl Glycoldi (meth) acrylate, bisphenol Adi (meth) acrylate, 2-ethyl, 2-butyl-propanedioldi (meth) acrylate, 1,9-nonanedioldi (meth) acrylate, hexyl 2, 2-bis [4- (methacryloxydiethoxy) phenyl] propane, 2,2-bis [4- (methacryloxydiethoxy) phenyl] propane, 3-phenoxy-2-propanoylacrylate, 1 , 6-bis (3-acryloxy-2-hydroxypropyl) -hexyl ether, trimethylolpropane tri (meth) acrylate, glycerin tri (meth) acrylate, tris- (2-hydroxyethyl) -isosia Nulic acid ester (meth) acrylate, pentaerythritol penta (meth) acrylate, dipenta Lisitol hexa (meth) acrylate, 2-hydroxypropyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth ) Acrylate, 2-ethylhexyl (meth) acrylate, stearyl acrylate, 2-ethylhexyl carbitol acrylate, ω-carboxypolycaprolactone monoacrylate, acryloyloxyethyl acid, acrylic acid dimer, lauryl (Methacrylate), 2-methoxyethyl acrylate, butoxyethyl acrylate, ethoxy ethoxy ethyl acrylate, methoxy triethylene glycol acrylate, methoxy polyethylene glycol acrylate, stearyl (meth) acrylate , Cyclohexyl (meth) acrylate, tetrahydrofurfuryl (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, nonyl phenol ethoxylated acrylate, acryloyloxy ethyl phthalic 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-metholacrylamide, N-methoxymethylacrylic Amide, N-ethoxymethylacrylamide, Nn-butoxymethylacrylamide, t-butylacrylamidesulfonic acid, vinyl stearyl acid, N-methylacrylamide, N -Dimethylacrylamide, N-dimethylaminoethyl (meth) acrylate, N-dimethylaminopropylacrylamide, glycidyl methacrylate, n-butyl methacrylate, ethyl methacrylate, allyl methacrylate, cetyl meta Acrylate, pentadecyl methacrylate, methoxypolyethylene glycol (meth) acrylate, diethylaminoethyl (meth) acrylate, methacryloxyethyl amber acid, hexanediol diacrylate, neopentyl glycol diacrylate, tri Ethylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, hydroxy pivalate ester neopentyl, pentaerythritol diacrylate monostearate, glycol diacrylate, 2-hydroxyethyl methacrylate Monophosphate, bisphenol A ethylene glycol adduct acrylate, bisphenol F ethylene glycol Adduct acrylate, tricyclodecanemethanol diacrylate, trishydroxyethyl isocyanurate diacrylate, 2-hydroxy-1 acryloxy-3-methacryloxy propane, trimetholpropane triacrylate, tri Methirol propane ethylene glycol adduct triacrylate, trimethol propane propylene glycol adduct triacrylate, pentaerythritol triacrylate, trisacryloyloxyethyl phosphate, trishydroxyethyl isocyanurate triacrylate, modified ε-caprolactone triacrylate, trimetholpropane ethoxytriacrylate, glyceryl propylene glycol adduct triacrylate, pentaerythritol tetraacrylate, pentaerythritol ethylene glycol adduct tetrahydrate, ditrimetholpropane tetra Acrylate, dipentaerythritol hexa (Penta) acrylate, dipentaerythritol monohydroxypentaacrylate, and an eptoacrylate are mentioned.

As polyester resin, linear polyester etc. which have a dicarboxylic acid component and a glycol component as a component can be used. Examples of the dicarboxylic acid component and the glycol component are shown below. These can also be used individually or in mixture of 2 or more types. 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, phenylindandi Carboxylic acid and dimer acid. Glycol Component: Ethylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylene glycol, dimethylolpropionic acid, glycerin, tri Methiolpropane, poly (ethyleneoxy) glycol, poly (tetramethyleneoxy) glycol, alkylene oxide adduct of bisphenol A and alkylene oxide adduct of hydrogenated bisphenol A.

As a urethane resin, what is normally obtained by polyaddition reaction of a polyisocyanate and an 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-diisocyanathmethylcaproate), bis (2-isocyanaethylethyl) fumalate, bis (2-isocyanaethylethyl) carbonate, 2-isocyanatoethyl-2,6-di Socyanatohexanoate, isophorone diisocyanate (IPDI), dicyclohexyl methane-4,4'- diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, bis (2-isosia Natethyl) -4-cyclohexene-1,2-dicarboxylate, 2,5- and / or 2,6-norbornane diisocyanate, m- and / or p-xylylenediisocyanate, α, α, α ', α'-tetramethylxylyl As the modified diisocyanate and polyisocyanate, modified MDI (urethane modified MDI, carbodiimide modified MDI, trihydrocarbyl phosphate modified MDI), urethane modified TDI, biuret modified HDI, isocyanurate modified HDI, isosi Modified products of polyisocyanates such as anurate-modified IPDI 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), branched diol ( Propylene glycol, neopentyl glycol, 3-methyl 1,5-pentanediol, 2,2-diethyl-1,3-propanediol, 1,2-, 1,3- or 2,3-butanediol), cyclic groups Diols having 1,4-bis (hydroxymethyl) cyclohexane, m- or p-xylylene glycol), dihydric phenol (bisphenol A), polyhydric alcohols (glycerine, trimetholpropane, pentaerythritol, sorbitol) , Sugars and derivatives thereof (sucrose, methylglucoside), aliphatic amines (ethylenediamine, hexamethylenediamine, etc.), alicyclic diamines (4,4'-diamino-3,3'-dimethyldicyclohexylmethane, 4, 4'diamino-3,3'-dimethyldicyclohexyl, diaminocyclohexane, isophoronediamine), aromatic diamine (diethyltoluenediamine), aromatic aliphatic diamine (xylylenediamine, α, α, α ', α'-tetrame Tyl xylylenediamine), heterocyclic diamine (piperidine), polyfunctional amine (diethylenetriamine, triethylenetetramine), high molecular polyol (polyester polyol, polyether polyol), aliphatic polycarbon (pump acid, glue) Deoxidation, maleic acid, fumaric acid, adipic acid, azaline acid, sebacic acid, hexahydrophthalic acid), aromatic polycarboxylic acid (phthalic acid, isophthalic acid, terephthalic acid, tetrabromphthalic acid, tetracrophthalic acid, trimellitic acid, pyromellitic acid, Of maleic anhydride, phthalic anhydride, dimethyl terephthalate, lactone monomers (γ-butyrolactone, ε-caprolactone, γ-valerolactone and compounds alkylene oxide having two or more active hydrogen atoms).

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

As polyvinyl alcohol-type resin, what is obtained by quenching the polyvinyl ether polymer obtained by radically polymerizing vinyl ester monomers, such as vinyl acetate, can be used. Examples of the polyvinyl ester polymers are shown below. These can be used individually or in mixture of 2 or more types. Polyvinyl ester type polymer: Polymers of vinyl esters, such as vinyl formate, vinyl acetate, a vinyl propionate, a vinyl valerate, a vinyl laurate, a vinyl stearate, a vinyl benzoate, a vinyl pivalate, and a vinyl vasatate. The polyvinyl ester polymer may be a copolymer obtained by copolymerizing copolymerizable comonomers of the above-mentioned vinyl ester monomers. Examples of the comonomer include olefins such as ethylene, propylene, 1-butene and isobutene, acrylic acid and salts thereof, and acrylic acid. Acrylic esters, such as methyl, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, and octadecyl acrylate, meta Methacrylic acid and its salts, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate Methacrylic acid esters such as 2-ethylhexyl methacrylate, dodecyl methacrylate and octadecyl methacrylate, acrylamide, hydroxyalkyl, N-methylacrylamide, N-ethylacrylamide, N, N- Dimethylacrylamide Acrylamide derivatives such as mead, diacetone acrylamide, acrylamide propanesulfonic acid and salts thereof, acrylamidepropyldimethylamine and salts thereof, or quaternary salts thereof, N-methyrolacrylamide and derivatives thereof, methacrylamide, N Methyl methacrylamide, N-ethyl methacrylamide, methacrylamide propanesulfonic acid and salts thereof, methacrylamidepropyldimethylamine and salts thereof, or quaternary salts thereof, N-methol methacrylamide and derivatives thereof, and the like. Methacrylamide derivatives, 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, stearyl Vinyl ethers such as vinyl ether, nitriles such as acrylonitrile and methacrylonitrile, vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride and vinylidene fluoride, There may be mentioned acid allyl, allyl compounds such as allyl chloride, dry phosphoric acid and a salt thereof, or vinyl silyl compounds, such as esters thereof, vinyl trimethoxysilane, isopropenyl acetate and so on.

As melamine resin, methylated melamine resin, butylated melamine resin, methyl butyl mixed resin, etc. can be used.

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

Examples of the 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 trimethate, Cellulose nitrate and 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 an alkyl group, an alkenyl group, an aryl group, an acyl group, a halogen group, a glycidoxy group, an epoxy group, an amino group, a phenyl group, a mercapto group, a methacryloxy group and a cyano group represents an organic group, R ² represents an organic group selected from the group consisting of an alkyl group, an alkoxy group, an acyl group and a phenyl group having a carbon number of 1-8, a and b is an integer of 0 or 1.) the organosilicon compound represented by the Or hydrolysates thereof.

B component: General formula (II)

{(OX) _3-a Si (R ⁴ )} ₂ Y (II)

(Wherein 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, Y represents an organic group having 2 to 20 carbon atoms, and a represents an integer of 0 or 1) Organosilicon compounds or hydrolyzates thereof.

A component is represented by general formula (I) mentioned above. Examples of the specific organosilicon compounds or hydrolyzates thereof: methyl silicate, ethyl silicate, n-propyl silicate, iso-propyl silicate, n-butyl silicate, tetraacetoxysilane, methyltrimethoxysilane, methyltripropoxysilane, Methyl triacetic silane, Methyl tributoxy silane, Methyl tripropoxy silane, Methyl tri hydroxy silane, Methyl tri phenoxy silane, Methyl tri benzyl oxy silane, Methyl tri phenethyl oxysilane, Glucidoxy methyl trimethoxy Silane, glycidoxymethyltrimethoxysilane, α-glycidoxyethyltrimethoxysilane, α-glycidoxycitrietic silane, β-glycidoxycitrimethoxysilane, β-glycidoxyethyltri Ethoxysilane, α-glycidoxypropyltrimethoxysilane, α-glycidoxypropyltriethoxysilane, β-glycidoxypropyltrimethoxysilane, β-glycidoxypropyltriethoxysilane, γ- Glycidoxif Philtrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltripropoxysilane, γ-glycidoxypropyltributoxysilane, γ-glycidoxypropyltriphenoxysilane, (alpha)-glycidoxy butyl trimethoxysilane, (alpha)-glycidoxy butyl triethoxysilane, (beta)-glycidoxy butyl triethoxysilane, (gamma)-glycidoxy butyl trimethoxysilane, (gamma)-glycidoxy butyl Triethoxysilane, δ-glycidoxybutyltrimethoxysilane, δ-glycidoxybutyltriethoxysilane, (3,4-epoxycyclohexyl) methyltrimethoxysilane), (3,4-epoxycyclo Hexyl) methyltriethoxysilane), β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, β-3,4-epoxy Cyclohexyl) ethyltripropoxysilane, β- (3,4-epoxycyclohexyl) ethyltributoxysilane, β- (3,4-epoxycyclohexyl) ethyltriphenoxysilane, γ- (3,4- Epoxycyclohexyl) propyltrimethoxysilane, γ- (3,4-epoxycyclohexyl) propyl triethoxysilane, 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-glycidoxypropyl Methyldimethoxysilane, β-glycidoxypropylethyldimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropylmethyldipropoxysilane, γ-glycidoxypropylmethyldibutoxysilane, γ-glycidoxypropylmethyl Diphenoxysilane, γ-glycidoxypropylethyldiethoxysilane, γ-glycidoxypropylethyldiethoxysilane, γ-glycidoxypropylvinylmethoxysilane, γ-glycidoxypropylvinylethoxysilane, γ -Glycidoxy propyl vinyl phenyl methoxysilane, gamma-glycidoxy propyl vinyl phenyl ethoxy silane, ethyl trimethoxy silane, ethyl triethoxy silane, vinyl trimethoxy silane, vinyl triacetoxy silane, vinyl trimeth Methoxyethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, γ-chloropropyltriacetoxysilane, 3,3,3-trichloropropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, β-cyanoethyl Triethoxysilane, chloromethyltrimethoxysilane, Loromethyltriethoxysilane, N- (β-aminoethyl) γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyltrimethoxysilane , N- (β-aminoethyl) γ-aminopropyltriethoxysilane, N- (β-aminoethyl) γ-aminopropylmethyldiethoxysilane, dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxy Silane, phenylmethyldiethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropylmethyldiethoxysilane, dimethyldiacetoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyl Diethoxysilane, gamma -mercaptopropylmethyldimethoxysilane, gamma -mercaptomethyldiethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, and hydrolyzates thereof.

B component is represented by general formula (II) mentioned above. Examples of the specific organosilicon compounds or hydrolyzates thereof: methylenebismethyldimethoxysilane, ethylenebisethyldimethoxysilane, propylenebisethyldiethoxysilane, butylenebismethyldiethoxysilane and hydrolysates thereof.

The organosilicon compound of A component and / or B component can be used individually by A component or B component, or can mix A component and B component. Moreover, it is also possible to use two or more types of A components, and to use two or more types of B components. Hydrolysis of the organosilicon compounds of component A and component B is performed by adding and stirring an acidic aqueous solution such as aqueous hydrochloric acid solution, aqueous sulfuric acid solution, or acetic acid aqueous solution to the organic silicon compound of component A and / or component B.

As the organosilicon compound, in addition to the silicon compound described above, modified silicone varnishes such as silicone varnish, silicone alky varnish, silicone epoxy varnish, silicone acrylic varnish and silicone polyester varnish can be used. These can be used individually or in mixture of 2 or more types.

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

Polyvinyl butyral is mentioned as a butyral resin.

Although the coating composition of this invention contains the said binder and sodium magnesium fluoride, if necessary, it is a solvent, a polymerization initiator, a hardening | curing agent, a crosslinking agent, a sunscreen, a ultraviolet absorber, a surface adjuster (leveling agent), or to prepare with a coating liquid, or You may mix | blend another component.

For example, when a binder has an ionizing radiation curable group, an optical radical polymerization initiator is used. Examples of the radical photopolymerization initiator include acetophenones, benzophenones, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds, Thiuram compounds, fluoroamine compounds, etc. are used. More specifically, 1-hydroxy cyclohexyl-phenyl- ketone, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholino propane- 1-one, benzyl dimethyl ketone, 1- ( 4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) -2 -Hydroxy-2-methylpropan-1-one, benzophenone, etc. can be illustrated. Among them, 1-hydroxycyclohexyl-phenyl-ketone and 2-methyl-1 [4- (methylthio) phenyl] -2morpholinopropane-1-one are polymerized by irradiation of ionizing radiation even in a small amount. It is preferable because the reaction is initiated and promoted. These may be used alone or in combination of both. These exist also as a commercial item, and 1-hydroxy cyclohexyl phenyl- ketone can be obtained from Chiba Specialty Chemicals Co., Ltd. under the brand name of Irgacure-184.

When using a radical photopolymerization initiator, it is preferable to mix | blend an optical radical polymerization initiator in the ratio of 1-30 mass parts normally with respect to a 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 a thermosetting polar group is a hydroxyl group, the compound which has a hydrolyzable group which produces | generates a hydroxyl group by hydrolysis, such as a compound using basic groups, such as a metyrolmelamine, and a metal alkoxide, is used normally as a hardening | curing agent.

When the thermosetting polar group of a binder component is an epoxy group, polyhydric carboxylic anhydride or polyhydric carboxylic acid is normally used as a hardening | curing agent in a coating composition. Specific examples of the polycarboxylic acid anhydride include phthalic anhydride, inthaconic anhydride, amber anhydride, citraconic anhydride, dodechenyl anhydride, tricarbaric anhydride, maleic anhydride, hexahydrophthalic anhydride, dimethyl tetrahydrophthalic anhydride, and anhydride. Aliphatic or cycloaliphatic dicarboxylic acid anhydrides such as himic acid and naproic anhydride; Aliphatic polyhydric carboxylic dianhydrides such as 1,2,3,4-butane tetracarboxylic dianhydride and cyclopenta tetracarboxylic dianhydride; Aromatic polyhydric carboxylic anhydrides such as pyromellitic anhydride, trimellitic anhydride, and benzophenone tetracarboxylic anhydride; Ester group containing acid anhydrides, such as ethylene glycol bistrimellitate and glycerol tristrimellitate, are mentioned, Especially preferably, aromatic polyhydric carboxylic anhydride is mentioned. Moreover, the epoxy resin hardening agent used as a commercial carboxylic anhydride can also be used suitably. Moreover, as a specific example of polyhydric carboxylic acid, Aliphatic polyhydric carboxylic acids, such as a succinic acid, glutaric acid, adipic acid, butanetetracarboxylic acid, maleic acid, itaconic acid; Aliphatic polyhydric carboxylic acids such as hexahydrophthalic acid, 1,2-cyclohexanedicarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, cyclopentanetetracarboxylic acid, and phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, Aromatic polyhydric carboxylic acids, such as trimellitic acid, 1,4,5,8-naphthalene tetracarboxylic acid, and benzophenone tetracarboxylic acid, are mentioned, Preferably aromatic polyhydric carboxylic acid is mentioned.

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

The solvent used in the coating composition of the present invention is not particularly limited, but various organic solvents, for example, alcohols such as isopropyl alcohol, methanol, ethanol and butanol, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone Ketones, such as 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. For example, methods, such as a chiffin coat method, the dipping method, the spray method, the slide coat method, the bar coat method, the roll coater method, the meniscus coater method, the flexographic printing method, the screen printing method, the bit coater method, are mentioned.

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

As the anti-reflection film, 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 medium-high refractive index layers are provided on the display surface in order to further improve the anti-reflection effect, and a medium-high refractive index On the layer, there is a layer structure in which a low refractive index layer is provided in order to lower the refractive index of the outermost surface. The optical member of the present invention may be used as an antireflection film by forming a film obtained by coating the coating composition of the present invention directly on the surface of an optical substrate, and may be used as an anti-reflection film. An antireflection film having a plurality of high refractive index layers may be formed.

The optical base material for coating the coating composition of the present invention is not particularly limited. For example, glass or triacetate cellulose (TAC), polyethylene terephthalate (PET), diacetyl cellulose, acetate butyrate cellulose, polyethyl salphone, acrylic resin, polyurethane resin, polyester, polycarbonate, polysulfone And films formed of various resins such as polyether, polymethylpentene, polyethyl ketone, and (methacrylonitrile).

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

EXAMPLE

Reference Example

(a) Process: 2268 g of sodium fluoride (NaF, Reagent Express, Kanto Chemical Co., Ltd.) was dissolved in 100 liters of pure water to prepare a 102.3 kg sodium fluoride aqueous solution. The sodium fluoride concentration in this aqueous solution was 2.22 mass%. On the other hand, 3654 g of magnesium chloride (MgCl ₂ · 6H ₂ O, reagent grade, manufactured by Kosofuka Chemical Co., Ltd.) was dissolved in 100 liters of pure water to prepare a 103.7 kg aqueous magnesium chloride solution. The concentration of magnesium chloride (MgCl- ₂ ) in the aqueous solution was 1.65 mass%. 102.3 kg of the aqueous sodium fluoride solution was poured into a 300 liter container, and 103.7 kg of the magnesium chloride aqueous solution was added at room temperature for 30 minutes while stirring vigorously using a disper, followed by further stirring for 1 hour. 206 kg of a slurry of colloidal particles of magnesium was obtained. The scheme is as follows.

3NaF + MgCl _2- > NaFMgF ₂ + 2NaCl

The sodium fluoride and magnesium chloride were 3.0 in a Na / Mg molar ratio.

The obtained slurry of colloidal particles of sodium magnesium fluoride is partially sol, but is precipitated by correction to form an aggregate of colloidal particles of sodium magnesium fluoride. The sodium magnesium fluoride concentration in this slurry was 0.91 mass%.

(b) Process: Ultrafiltration 420 kg of a slurry slurry of colloidal particles of sodium magnesium fluoride obtained in the step (a) was subjected to ultrafiltration using a tube type ultrafiltration apparatus (UF (PS-150), manufactured by Mitsubishi Rayon Engineering Co., Ltd.). Filtration washing was performed while adding at the same speed as the speed. The liquid crystal of the slurry in filtration cleaning was 25 ° C, and the filtration time was 15.5 hours. The solid content concentration of the filtrate when washing was about 3.0 mass% as NaF · MgF _2. After filtration and washing, the mixture was concentrated by the same ultrafiltration apparatus to obtain 6170 g of an aggregate slurry of colloidal particles of sodium magnesium fluoride substantially free of salts. The aggregate slurry of the colloidal particles of sodium magnesium fluoride obtained in the step (b) was 28.0 mass% of sodium magnesium fluoride concentration (NaF · MgF ₂ ) and conductivity of 870 Pa / cm, and a portion of the aggregate was precipitated by standing. The yield of sodium magnesium fluoride was approximately 92%.

(c) step: 500 g of ceramic grinding beads are added to 670 g of an aggregate slurry of colloidal particles of sodium magnesium fluoride substantially free of salts obtained in the step (b), and a batch sand grinder (rotation speed 2000r. pm, and maintained at room temperature by cooling) for 8 hours to obtain an aqueous magnesium fluoride sol. In the case where the sol was recovered after the completion of the pulverization, the pulverized 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 mass%, and a conductivity of 410 Pa / cm.

This sodium magnesium fluoride aqueous sol was subjected to methanol substitution under a reduced pressure using a rotary evaporator to obtain sodium magnesium fluoride sol. Sodium magnesium fluoride sol-propanol was obtained in specific gravity of 0.84, with purified water pH 8.4, viscosity of 7.8mPa · S, sodium magnesium fluoride in the case of dilution with _{1 + 1 (NaF · MgF 2} ) concentration was 10.5% by mass. Further, the fluorinated When Romance sodium magnesium isopropanol sol minute color difference meter TC-1800MK-II ((oil) Tokyo Denshoku claim) of sodium magnesium fluoride by using (NaF · MgF ₂₎ concentration in the light transmittance of the sol was adjusted to 5% by weight The light transmittance at a wavelength of 500 nm at an optical path length of 10 mm was 99.0%, and the average particle diameter was 40 nm and 80 nm in the dynamic light scattering method as observed by an electron microscope.

Example 1

0.02 g of 0.43 g of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.) and Irgacure 184 (manufactured by Chiba Specialty Chemicals Co., Ltd.) to 10.5 g of sodium fluoride isopropanol sol obtained in the reference example, 19.0 g of isopropanol were added to prepare a coating composition containing sodium magnesium fluoride. After applying the obtained coating composition on the silicon wafer cut to 5 cm X 5 cm using a spin coater, the low refractive index film was produced by irradiating an ultraviolet-ray. As a result of measuring the obtained low refractive index film with the lipsomr (five lab MARY-102), the refractive index was 1.4799 and the film thickness was 892 GPa.

Example 2

To 7.5 g of sodium magnesium fluoride isopropanol sol obtained in the reference example, 0.04 g of dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.) and Irgacure 184 (manufactured by Chiba Specialty Chemicals Co., Ltd.), 15.0 g of isopropanol were added to prepare a coating composition containing sodium magnesium fluoride. The obtained coating composition was applied onto a silicon wafer cut to 5 cm X 5 cm using a spin coater, and then irradiated with ultraviolet rays to prepare a low refractive index film. As a result of measuring the obtained low refractive index film with the lipsomr (five lab MARY-102), the refractive index was 1.4361 and the film thickness was 993 GPa.

Example 3

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

Comparative Example 1

To 3.3 g of silica isopropanol sol (brand name IPA-ST: Nissan Kagaku Kogyo Co., Ltd.), 0.95 g of dipentaerythritol hexaacrylate (manufactured by Nissan Kayaku Co., Ltd.) and Irkacure 184 (Chiba Specialty Chemicals) 0.05 g and 35.7 g of isopropanol were added to Co., Ltd., and the coating composition containing a silica was prepared. After applying the obtained coating composition on the silicon wafer cut to 5 cm X 5 cm using a spin coater, the low refractive index film was produced by irradiating an ultraviolet-ray. The obtained low refractive index film was measured with an ellipsometer (five lab MARY-102), and the refractive index was 1.4917 and the film thickness was 926 GPa.

Comparative Example 2

To 7.5 g of magnesium fluoride isopropanol sol (MFS-10P: Nissan Kagaku Kogyo Co., Ltd.), 0.71 g of dipentaerythritol hexaacrylate (manufactured by Nissan Kayaku Co., Ltd.) and Irkacure 184 (Ciba specialty chemicals) 0.04g and 15.0g of isopropanol were added to (Co., Ltd.), and the coating composition containing magnesium fluoride was prepared. The obtained coating composition was applied onto a silicon wafer cut to 5 cm X 5 cm using a spin coater, and then irradiated with ultraviolet rays to prepare a low refractive index film. The obtained low refractive index film was measured with an ellipsometer (five lab MARY-102), and the refractive index was 1.4536 and the film thickness was 967 GPa.

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

Claims (3)

A coating composition comprising a sodium magnesium fluoride sol and a binder having a light transmittance of 80% or more at a wavelength of 500 nm at an optical length of 10 mm of a sol prepared with a sodium magnesium fluoride (NaF.MgF ₂ ) concentration of 5% by mass. The method of claim 1, wherein 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 Coating composition which is at least 1 sort (s) chosen from the group which consists of a compound, a urea resin, a diallyl phthalate resin, and a butyral resin. An optical member having a film formed from the coating composition according to claim 1 on the surface of an optical substrate.