WO2006057119A1

WO2006057119A1 - Inorganic coating composition, coating film with low refractive index and method for forming coating film with low refractive index

Info

Publication number: WO2006057119A1
Application number: PCT/JP2005/019065
Authority: WO
Inventors: Youhei Kawai; Takashige Yoneda
Original assignee: Asahi Glass Company, Limited
Priority date: 2004-11-26
Filing date: 2005-10-17
Publication date: 2006-06-01
Also published as: TW200626682A; JPWO2006057119A1

Abstract

Disclosed is an inorganic coating composition which enables to form a coating film with low refractive index which has high transparency and excellent adhesion to an organic base. Specifically disclosed is an inorganic coating composition which enables to form a coating film with low refractive index on an organic base. Such an inorganic coating composition contains 0.1-20% by mass of hollow silica particles having an average particle diameter of 5-3000 nm, 1-20% by mass of a water-miscible organic solvent which is capable of swelling or dissolving the organic base and has a boiling point of not less than 130˚C at an air pressure of 0.1 MPa, and 60-98.9% by mass of another water-miscible organic solvent which does not substantially swell or dissolve the organic base and has a boiling point of 50-120˚C at an air pressure of 0.1 MPa.

Description

Specification

Inorganic coating composition, low refractive index coating film and method for forming low refractive index coating film

The present invention relates to an inorganic coating composition that can form a highly transparent low refractive index coating film, a low refractive index coating film, and a method for forming a low refractive index coating film.

Background art

[0002] Conventionally, various low-refractive-index coating films have been formed on display panel cover materials and organic substrates such as optical lenses, optical filters, and polarizing films for the purpose of reducing reflectivity. Various methods are being studied. As a part of this study, sputtering, CVD and other vapor deposition methods can be mentioned. However, in the case of an organic substrate, it cannot be heated to a high temperature, and an organic substrate and a coating film with sufficient adhesion can be obtained. There is no problem. In addition, the above-described vapor deposition method generally requires a large amount of capital investment and increases the cost, and there is a problem that it is difficult in terms of production technology for a large-area substrate. For this reason, since it can be produced inexpensively with a simple apparatus, for example, there is a wet method in which a coating liquid containing porous silica fine particles and a binder is applied to form a low refractive index coating film (Patent Literature). 1). However, in this wet method, since a binder is essential, a coating film obtained by the influence of the binder that has a low reflectivity cannot be obtained. In addition, when forming inorganic particles such as silica on an organic substrate, a primer layer or a hard coat layer may be required as an intermediate layer in order to improve the adhesion between the organic substrate and the inorganic particles. There is a problem that becomes higher.

[0003] In addition, as a method for forming a strong silica film on an organic substrate such as polycarbonate, silica having a hydrophobic treatment, water, and an organic solvent such as cellosolve acetate that is soluble in the organic substrate are included. A paint is disclosed (Patent Document 2). However, this method has a problem that since the organic base material contains a large amount of an organic solvent that is soluble in the organic base material, erosion of the organic base material is considerably advanced, and the obtained coated product is easily clouded.

[0004] Patent Document 1: Japanese Patent Laid-Open No. 7-48527

Patent Document 2: US Patent No. 4413088 Disclosure of the invention

Problems to be solved by the invention

[0005] The present invention provides an inorganic coating composition, a low refractive index coating film and a low refractive index property which can form a low refractive index coating film having high transparency and excellent adhesion to an organic substrate. It aims at providing the method of forming a coating film.

Means for solving the problem

[0006] The present invention has the following features.

(1) (a) Hollow silica particles having an average particle diameter of 5 to 3000 nm are 0.:! To 20% by mass; (b) Organic base material can be swollen or dissolved, and atmospheric pressure is 0. IMPa state 1 to 20% by mass of water-miscible organic solvent A with a boiling point of 130 ° C or higher; (c) without substantially swelling or dissolving the organic base material and at a pressure of 0. IMPa with a boiling point of 50 ~ 120 ° C water-miscible organic solvent B and Z or (d) 60 ~ 98.9% by weight of water, can form low refractive index coating on organic substrate Inorganic coating composition.

(2) The inorganic coating composition according to (1), wherein the organic base material is made of polycarbonate or acrylic resin.

(3) The organic solvent A is a group consisting of diglyme, N, N dimethylformamide, N, N dimethylacetamide, acetoacetate, N methyl 2-pyrrolidinone, 2 pyrrolidinone, 1,3 dimethylenoyl 2-imidazolidinone and dimethyl sulfoxide. The inorganic coating composition according to the above (1) or (2), which is at least one selected from the above.

(4) Organic solvent power that is miscible with water and does not substantially swell or dissolve the organic base material, and has a boiling point of 50 to 120 ° C in the state of atmospheric pressure 0. IMPa, methanol, ethanol, n-propanol The inorganic coating composition according to any one of the above (1) to (3), which is at least one selected from the group consisting of: isopropanol, n-butanol, isobutanol, sec-butanol, and t-butanol.

(5) A low refractive index coating film obtained by applying the inorganic coating composition described in (1) to (4) above to an organic substrate.

(6) The low refractive index coating film according to (5), wherein the low refractive index coating film has a haze of 1% or less in accordance with the standard of JIS K-7150. (7) The low refractive index coating film according to the above (5) or (6), wherein the low refractive index coating film has a refractive index of 1.:! To 1.4.

(8) (a) 0 to 20% by mass of hollow silica particles having an average particle diameter of 5 to 3000 nm; (b) An organic base material can be swollen or dissolved, and the atmospheric pressure is 0. IMPa state 1 to 20% by mass of water-miscible organic solvent A with a boiling point of 130 ° C or higher; (c) without substantially swelling or dissolving the organic base material and at a pressure of 0. IMPa with a boiling point of 50 A step of preparing an inorganic coating composition containing water-miscible organic solvent B and Z or (d) 60 to 98.9% by mass of water; A method for forming a low refractive index coating film, comprising: a step of forming a low refractive index coating film by coating and drying on an organic substrate.

The invention's effect

[0007] According to the present invention, it is possible to obtain an inorganic coating composition and a low refractive index coating film that can form a low refractive index coating film having high transparency and excellent adhesion to an organic substrate. The present invention can also provide a simple and inexpensive method for forming a low refractive index coating film. BEST MODE FOR CARRYING OUT THE INVENTION

[0008] The inorganic coating composition of the present invention contains (a) hollow silica particles, (b) an organic solvent A, and (c) an organic solvent B and Z or (d) water.

In the present invention, (a) the hollow silica particles are required to have an average particle diameter of 5 to 3000 nm. If the average particle size is less than 5 nm, the hollow silica particles become unstable in the inorganic coating composition, and the particles may be aggregated and become too large. When a coating film is formed, it is difficult to embed it in an organic base material, and the adhesion may be lowered. The hollow silica particles preferably have an average particle size of 5 to 200 nm, particularly preferably an average particle size of 5 to 200 nm, because the resulting coating film is excellent in transparency. In the present specification, the average particle diameter of the hollow silica particles is based on mass.

[0010] The hollow silica particles preferably have a refractive index of 1.2 to 1.5. This is preferable because a low refractive index coating film can be obtained. The refractive index of the hollow silica particles is preferably measured, for example, by the method described in JP-A-2001-233611. Specifically, various standard solutions with known refractive indexes were dropped on a glass plate with a few drops, and a hollow sheet was added to the solution. An example is a method in which liquid particles are mixed so that the refractive index of the standard solution when the mixed solution becomes transparent is the refractive index of the hollow silica particles. When the hollow silica particles are contained in the dispersion, it is preferable to use the powder after drying the dispersion medium after evaporating the dispersion medium in the dispersion. It is particularly preferable that the hollow silica particles have a refractive index of 1.3 to 1.4.

In the present specification, the hollow silica particles are silica particles having pores inside the particles, and the outer shell portion other than the pores may be porous or non-porous. Can be used as needed. As a method for producing hollow silica particles, for example, porous inorganic particles are used as the core particles, and the core particles are coated with silica using caustic acid around the core particles, and then the core particles are coated with an acid. There is a method for obtaining hollow particles by dissolution. Hollow silica particles with a pore size of 1/3 to 2/3 of the particle size are preferred.

In the present invention, an organic solvent A is contained in the inorganic coating composition. Thereby, the adhesiveness of the obtained coating film can be improved. Although the mechanism by which the adhesion to the organic substrate is improved by containing the organic solvent A has not been elucidated, the organic solvent A swells or dissolves the organic substrate so that the surface of the organic substrate becomes microscopic. After creating a defect site and hollow silica particles infiltrating into the micro-defect site, the organic solvent A volatilizes, causing resin shrinkage at the surface of the organic substrate, and the hollow silica particles are supported in the organic substrate. It is thought that it is fixed in the locked state.

[0012] The organic solvent A can swell or dissolve the organic base material and has a boiling point of 130 ° C or higher at a pressure of 0. IMPa. When preparing the inorganic coating composition, the organic solvent A must be mixed with water in the inorganic coating composition so that the inorganic coating composition does not cause phase separation. For this reason, organic solvent A preferably has a water solubility of 2 or higher. In the present invention, the solubility in water means the amount (g) of the organic solvent A dissolved in water lOOg at a temperature of 20 ° C.

[0013] In addition, when the organic solvent A has a boiling point of 130 ° C or higher in a state where the atmospheric pressure is 0.1 IMPa, it can remain in the inorganic coating composition to the end as compared with the organic solvent B and water. The following effects can be shown. The organic solvent A particularly preferably has a boiling point of 160 to 300 ° C. under a pressure of 0.1 IMPa. In the present invention, “atmospheric pressure” means absolute pressure. To do.

Organic solvent A consists of diglyme, N, N-dimethylformamide, N, N-dimethylacetamide, acetoacetate, N-methyl-2-pyrrolidinone, 2-pyrrolidinone, 1,3-dimethyl_2 _imidazolidinone and dimethyl Any one selected from the group consisting of sulfoxide power and the like is preferable.

[0014] The inorganic coating composition of the present invention contains an organic solvent B and Z or water. Similarly to the organic solvent A, the organic solvent B must be mixed with water in the inorganic coating composition so that the inorganic coating composition does not cause phase separation. is there. For this reason, the organic solvent B preferably has a water solubility of 2 or more. The organic solvent B and water can be used in any proportion, and each may be used alone as described below.

Organic solvent B and water serve to stably disperse the hollow silica particles in the inorganic coating composition. Further, the organic solvent B is particularly preferable because it also serves to improve the coating property of the inorganic coating composition. By containing the organic solvent B and water, when the inorganic coating composition is applied and dried, the organic substrate A evaporates faster than the organic solvent A. The organic base material can be uniformly swelled or dissolved, which is preferable. The organic solvent B needs to have a boiling point of 50 to 120 ° C. without substantially swelling or dissolving the organic base material and at a pressure of 0. IMPa. If the boiling point of the organic solvent B is less than 50 ° C, it will volatilize at room temperature and it will be difficult to handle the inorganic coating composition.Therefore, if the boiling point is over 120 ° C, it will not volatilize. This is not preferable because the adhesion between the organic base material and the hollow silica particles may be hindered. It is preferable to use an organic solvent B having an atmospheric pressure of 0. IMPa and a boiling point of about 50 to 80 ° C. lower than the boiling point of the organic solvent A.

As the organic solvent B, for example, methanol selected from the group consisting of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol and t-butanol is preferable. .

[0015] The inorganic coating composition of the present invention can contain a surfactant as necessary. Surfactants include anionic surfactants, cationic surfactants, and nonionic surfactants. Any of the surfactants can be used. It is preferable to contain a surfactant because it has excellent wettability with respect to an organic substrate. As surfactant, -CH

2

CH 2 O—, —SO—, —NR— (R is a hydrogen atom or an organic group), —NH, —SO Y, or

2 2 2 3

Nonionic surfactants having a structural unit of _COOY (Y is a hydrogen atom, a sodium atom, a potassium atom or an ammonium ion) are preferred. Among them, there is no risk of impairing the storage stability of the inorganic coating composition.

twenty two

Of these, surfactants are particularly preferred.

Nonionic surfactants include, for example, alkyl polyoxyethylene ethers, alkyl polyoxyethylene monopolypropylene ethers, fatty acid polyoxyethylene esters, fatty acid polyoxyethylene sorbitan esters, fatty acid polyoxyethylene sonolebitole esterol, Examples thereof include alkyl polyoxyethylene amine, alkyl polyoxyethylene amide, and polyether-modified silicone surfactants.

[0016] In addition, the inorganic coating composition of the present invention can contain additives such as coloring dyes, pigments, ultraviolet absorbers and antioxidants as necessary.

[0017] The content of the organic solvent A is required to be 1 to 20% by mass of the inorganic coating composition. As described above, the organic solvent A is considered to function to swell or dissolve the organic base material so that the hollow silica particles are carried in the base material. Accordingly, the organic solvent A depends on the total concentration, not the solid content, in the inorganic coating composition which only needs to be present in an amount covering the surface of the organic substrate. If the content of the organic solvent A is less than 1% by mass, the adhesion of the resulting coating film to the organic substrate may be reduced, such being undesirable. Further, if the content of the organic solvent A exceeds 20% by mass, the influence of erosion on the organic base material is increased, the smoothness of the surface is impaired, and the transparency of the coating film may be reduced. Furthermore, this is preferable because the appearance of the coating film may be deteriorated. The content of the organic solvent A is particularly preferably 3 to 10% by mass.

[0018] The contents of the organic solvent B and water are required to be 60 to 98.9% by mass of the inorganic coating composition. If the content of the organic solvent B and water is less than 60% by mass, the hollow silica particles or the organic solvent A exceeds the predetermined range, which is not preferable. If it exceeds 99.9% by mass, the amount of the organic solvent A is small. As a result, the adhesion of the low refractive index coating film to the organic substrate is reduced. This is not preferable. It should be noted that the total amount of the organic solvent B and water may be 60 to 98.9% by mass regardless of whether they are blended in an arbitrary ratio or used alone. That is, the inorganic coating composition of the present invention may not contain any of the organic solvent B or water. The content of the organic solvent B and water is particularly preferably 80 to 97% by mass.

[0019] The solid content of the inorganic coating composition of the present invention is required to be 0.:! To 20% by mass. When the solid content is less than 0.1% by mass, unevenness is likely to occur when the inorganic coating composition is applied. Therefore, when the solid content is preferably over 20% by mass, This is preferable because there is a possibility that the workability of the product may deteriorate. The solid content of the inorganic coating composition is particularly preferably 0.1 to 10% by mass.

[0020] In the inorganic coating composition of the present invention, the surfactant is preferably 1 to 500 ppm. Surfactant power If it is less than Slppm, the wettability of the inorganic coating composition will decrease, and the workability during application may be impaired. This is not preferable because the quality of the appearance of the film may be deteriorated. The surfactant is particularly preferably 10 to 400 ppm.

[0021] The inorganic coating composition of the present invention preferably contains 1 to 50 parts by mass of a kaic acid oligomer in terms of solid content with respect to 100 parts by mass of the hollow silica particles as necessary. This is preferable because the strength of the obtained coating film can be improved. If the content of the carboxylic acid oligomer is less than 1 part by mass, there is almost no effect of improving the strength of the coating film. This is preferable because there is a risk of increasing. The content of the carboxylic acid oligomer is particularly preferably 1 to 30 parts by mass.

[0022] Examples of the carboxylic acid oligomer include a method in which an alkoxide of carboxylic acid such as ketyl ketate is decomposed in water, a method in which an alkali metal silicate is decomposed with an acid and then dialyzed, and an alkali metal silicate is peptized. A method obtained by a method, a method of contacting an alkali metal silicate with an acid-type cation exchange resin, or the like is preferable. In particular, the caylic acid oligomer obtained by contacting the alkali metal silicate with an acid type cation exchange resin has a high purity, and when the coating film is formed, the binder is strong. preferable. As the alkali metal silicate, sodium silicate, potassium silicate, lithium silicate and the like are preferable. As the ion exchange resin, conventionally known ones can be used. For example, it is preferable to use a cation exchange resin having an SOH group, a COOH group or the like. use

Three

The amount of alkali metal ions to be removed can be adjusted by controlling the amount of cation exchange resin to be used, contact time, contact method, and the like. In the present specification, the carboxylic acid oligomer means a polymer in which about 2 to 20 SiO molecules are polymerized in a dispersion medium. In the carboxylic acid oligomer,

2

It is preferable that 95% or more of the alkali metal is removed. This is preferable because a low-refractive-index coating film having excellent weather resistance can be obtained.

[0023] The carboxylic acid oligomer is preferably used as a dispersion by appropriately dispersing it in water or an organic solvent such as methanol, ethanol, isopropanol and the like as necessary. The content of Kei acid oligomer in the dispersion 1: is preferably 10 mass ^_0/0.

[0024] The inorganic coating composition of the present invention can form a low refractive index coating film by applying it to an organic substrate. The obtained coating film preferably has a refractive index of 1.:! To 1.4. As the organic base material, it is preferable to use a substrate made of force polycarbonate or acrylic resin, which can be used in various ways as needed. In addition, the shape of the substrate is not limited to a flat plate, and the entire surface or a part thereof has a curvature.

[0025] The coating film obtained by the present invention preferably has a minimum value of reflectance of 1% or less in the wavelength region of 380 to 780 nm. Reflectance is preferably measured with a spectrophotometer. If the minimum value of the reflectance is more than 1%, the function as a low refractive index coating film may be insufficient, which is preferable. The thickness of the coating film obtained by the present invention is preferably adjusted so that the reflectance at a wavelength of 550 nm takes a minimum value. The film thickness can be adjusted by the formula λ138Ζη (where λ is the wavelength of light and η is the refractive index of the film).

[0026] Further, since the low refractive index coating film obtained by applying the inorganic coating composition of the present invention is excellent in transparency, it is used particularly when the organic substrate is transparent. Is suitable. The transparency is preferably evaluated by haze value according to the standard of JIS K7150. The obtained low refractive index coating film preferably has a haze value of 1% or less. When the haze value is more than 1%, the transparency of the coating film is deteriorated and the transmittance is lowered, which is preferable. The haze value of the obtained coating film is particularly preferably 0.5% or less. [0027] In the present invention, an inorganic coating composition containing 0.:! To 20% by mass of hollow silica particles, 1 to 20% by mass of organic solvent A, 60 to 98.9% by mass of organic solvent B and water. Forming a low-refractive-index coating film through a process for adjusting the coating film, and a process for forming a low-refractive-index coating film by applying and drying an inorganic coating composition on an organic substrate. Is preferable.

[0028] The inorganic coating composition of the present invention can be applied by a known method. For example, brush coating, roller coating, hand coating, spin coating, dip coating, coating by various printing methods, curtain flow, coating, gravel coating, gravure coating, linole coating, ronor coating, flow coating, spray coating, dip coating, etc. Is mentioned. Further, for the purpose of increasing the mechanical strength of the coating film, irradiation with heating, ultraviolet rays, electron beams or the like may be performed as necessary. The heating may be determined taking into consideration the heat resistance of the organic base material, but is preferably 60 to 100 ° C. When applying the inorganic coating composition of the present invention, pretreatment is not particularly required for the organic substrate, but plasma treatment, corona treatment, UV treatment, Discharge treatment such as water treatment, chemical treatment such as water, acid or alkali, or physical treatment using an abrasive can be performed.

In the present invention, the thickness of the obtained coating film is preferably 30 to 3000 nm. If the thickness of the coating film is less than 30 nm, the function as a low refractive index coating film may be insufficient. Therefore, if the coating film thickness is more than 3000 nm, cracks tend to occur. Interference fringes or scratches are likely to be noticeable. It is particularly preferable that the coating film has a film thickness of 50-:! OOOnm.

Example

[0030] Examples 1, 2, 5, and 6 are shown below as examples. Examples 3 and 4 are shown as comparative examples.

Hereinafter, the mass% is simply indicated by%. The refractive index of the hollow silica particles is determined by the following method. That is, the dispersion medium is evaporated from the hollow silica fine particle-dispersed sol by an evaporator and then dried at 120 ° C. to obtain a powder. A few drops of standard refractive liquid with a known refractive index are dropped on a glass plate, and the above powder is mixed therewith. This operation is performed with various standard refractive liquids, and the refractive index of the standard refractive liquid when the mixed liquid becomes transparent is used as the refractive index of the fine particles.

[0031] [Example 1] Dispersion sol of hollow silica fine particles (average particle size 60 nm, pore size 30 nm, refractive index 1.3, solid content 20% isopropanol as a solvent, isopropanol as a solvent in a 200 ml glass reaction vessel. Has a boiling point of 8 · 3 ° C at 0 ° IMPa.) 5 g, 85 g of isopropanol, N, N-dimethylacetamide (pressure 0 66 ° C at IMPa 1 66 ° C, against water (Solubility: dissolves at an arbitrary ratio) 10 g is added and mixed, and then stirred at 20 ° C. for 1 hour to obtain an inorganic coating composition having a solid content of 1%. The content of N, N-dimethylacetamide is 10%, and the content of isopropanol is 89%.

[0032] [Evaluation test]

Using the resulting inorganic coating composition, it was applied onto a polycarbonate plate wiped with ethanol (length 10 Omm x width 100 mm, thickness 3.5 mm, refractive index: 1.584), and rotated at 150 rpm for 70 rpm. After spin coating for 2 seconds, dry at 100 ° C for 20 seconds to form a coating with a thickness of lOOnm.

[0033] Hereinafter, evaluation is performed by the following method on a sampnore having a coating film formed thereon. The evaluation results are shown in Table 1. In Examples 2 to 6, the same operations as in Example 1 were performed using the resulting inorganic coating composition, and evaluation was performed. The evaluation results are also shown in Table 1.

[0034] As an appearance evaluation, coating unevenness of the obtained coating film is visually determined. Evaluate as ◯ when there is no uneven coating and good appearance, and X when there is uneven coating and impractical.

[0035] As the transparency evaluation, evaluation is performed based on a haze value. The haze measurement is evaluated according to JIS K7150. The haze value of the coating film on the substrate is measured with a haze computer (model name: HGM-3DP, manufactured by Suga Test Instruments Co., Ltd.). A haze value of 1% or less is accepted, and a haze value exceeding 1% is rejected.

[0036] As a reflectance evaluation, the reflectance of the obtained coating film is measured using a spectrophotometer (manufactured by Hitachi, Ltd., model: U-4100). The rating is less than 1% reflectivity at 550nm.

[0037] As the refractive index evaluation, the refractive index of the obtained coating film is measured using an ellipsometer (manufactured by ULVAC, model: ESM-1AT). A refractive index in the range of 1.1 to 1.4 is acceptable.

[0038] As an evaluation of adhesion, cellophane tape was adhered to the coating film in the sample, Observe the peeling state of the coating film with the naked eye when the tape is peeled off. ◯ indicates that the coating film is not peeled off at all, △ indicates that a part of the coating film is peeled off but more than half of the area remains, and X indicates that more than half is peeled off.

[0039] As an evaluation of abrasion resistance, the surface of the coating film of the sample was worn back and forth 100 times with a cotton cloth, and the peeling state of the coating film was observed with the naked eye. ◯ is when the coating film is not peeled off at all, △ is when the area of more than half of the part is peeled off, and X when more than half is peeled off.

[0040] [Example 2]

In Example 1, 85 g of isopropanol, 85 g of water and 0.1% nonionic surfactant (product name: L-77, manufactured by Nippon Tunica Co., Ltd.) ethanol solution (note that ethanol is at a pressure of 0. IMPa) The boiling point is 78.2 ° C.) Except for changing to 0.lg, the same operation is carried out to obtain an inorganic coating composition having a solid content of 1%. The N, N_dimethylacetamide content is 10%, and the total content of isopropanol, water and ethanol is 89%.

[0041] [Example 3]

In Example 1, except that isopropanol is 65 g and N, N-dimethylacetamide is 30 g, the same operation as in Example 1 is performed to obtain an inorganic coating composition having a solid content of 1%. The N, N-dimethylacetamide content is 30% and the isopropanol content is 69%.

[0042] [Example 4]

In Example 1, an inorganic coating composition having a solid content of 1% is obtained in the same manner as in Example 1 except that 95 g of isopropanol is used without using N, N-dimethylacetamide. The isopropanol content is 99%.

[0043] [Example 5]

In Example 1, 93 g of isopropanol is used, and 2 g of pyrrolidinone (pressure 0. boiling point 245 ° C at IMPa, solubility in water: dissolve in any ratio) instead of N, N-dimethylacetamide is 2 g. Except for the above, the same operation as in Example 1 is carried out to obtain an inorganic coating composition having a solid content of 1%. The content of 2-pyrrolidinone is 2%, and the content of isopropanol is 97%. [0044] [Example 6]

In Example 1, except that the base material is changed to polymethylmethacrylate (refractive index: 1.521), the same operation as in Example 1 is performed to form a coating film.

[0045] [Table 1]

Industrial applicability

By using the inorganic coating composition of the present invention, a low refractive index coating film can be imparted to various articles having an organic substrate such as a display panel cover material, an optical lens, an optical filter, and a polarizing film. it can. It should be noted that the entire contents of Japanese Patent Application No. 2004-342184 filed on November 26, 2004, Akito Ida, the scope of claims, and the abstract are cited herein as the disclosure of the specification of the present invention. It is something that is incorporated.

Claims

The scope of the claims

[1] (a) The hollow silica particles having an average particle diameter of 5 to 3000 nm are 0.:! To 20% by mass; (b) the organic substrate can be swollen or dissolved, and the atmospheric pressure is 0. IMPa state 1 to 20% by mass of water-miscible organic solvent A having a boiling point of 130 ° C or higher; (c) boiling point at a pressure of 0. IMPa without substantially swelling or dissolving the organic base material 50 to 120 ° C of an organic solvent B and Z or (d) containing 60 to 98.9% by weight of water-miscible organic solvent B and forming a low refractive index coating film on an organic substrate. Inorganic coating composition.

[2] The inorganic coating composition according to claim 1, wherein the organic substrate is made of polycarbonate or acrylic resin.

[3] The organic solvent A is composed of diglyme, N, N dimethylformamide, N, N dimethylacetamide, acetoacetate ethyl, N-methyl 2 pyrrolidinone, 2 pyrrolidinone, 1,3-dimethinole 2-imidazolidinone and dimethyl sulfoxide. The inorganic coating composition according to claim 1 or 2, which is at least one selected from the group consisting of:

[4] Organic solvent power that is miscible with water and has a boiling point of 50 to 120 ° C in the state of atmospheric pressure 0. IMPa without substantially swelling or dissolving the organic base material Methanol, ethanol, n-propanol, isopropanol The inorganic coating composition according to any one of claims 1 to 3, which is at least one selected from the group consisting of n-butanol, isobutanol, sec-butanol and t-butanol.

[5] A low refractive index coating film obtained by applying the inorganic coating composition according to any one of claims 1 to 4 to an organic substrate.

[6] The low refractive index coating film according to claim 5, wherein the low refractive index coating film has a haze of 1% or less in accordance with JIS K-7150 standards.

7. The low refractive index coating film according to claim 5 or 6, wherein the low refractive index coating film has a refractive index of 1.1 to 1.4.

[8] (a) Hollow silica particles having an average particle diameter of 5 to 3000 nm are 0.:! To 20% by mass; (b) The organic substrate can be swollen or dissolved, and the atmospheric pressure is 0. IMPa state 1 to 20% by mass of water-miscible organic solvent A having a boiling point of 130 ° C or higher; (c) boiling point at a pressure of 0. IMPa without substantially swelling or dissolving the organic base material 50 ~: 120 ° C organic, miscible with water A step of preparing an inorganic coating composition containing Solvent B and / or (d) 60 to 98.9% by weight of water; and applying and drying the inorganic coating composition on an organic substrate; A method for forming a low-refractive-index coating film, comprising a step of forming a refractive-index coating film.