JP6631656B2 - Inorganic oxide dispersion with high transparency - Google Patents

Description

  The present invention relates to an inorganic oxide dispersion having high transparency and inks, paints, coating liquids, coating films, and films containing the dispersion.

  A technique of mixing an inorganic oxide such as silica with a resin in order to achieve mechanical and optical properties that are difficult to achieve with a resin alone in applications such as paints and films has been attempted for a long time. When mixing an inorganic oxide and a resin, a method using a dispersion in which an inorganic oxide is dispersed to a nanometer level has been used for the purpose of improving mechanical properties and optical properties.

  The problem is that when the inorganic oxide is finely dispersed to the nano level, a large amount of a dispersing agent is required to stabilize the dispersion of the inorganic oxide, and the properties required for paints and films are reduced. Can be In order to solve this problem, it has been proposed to introduce a skeleton having a dispersing property into a binder so as to minimize the deterioration of properties, but the applicable applications are limited. (Patent Document 1) Further, a method has been proposed in which the influence on the final physical properties is minimized by removing excess coupling agent by heating during film processing by treating with a low boiling point coupling agent. However, although zirconia and titanium can be dispersed in a certain limited solvent system applicable to processing, it has been difficult to develop it depending on the type of inorganic oxide. (Patent Document 2) Further, it has been proposed to stabilize a titania sol in an organic solvent by using a hydroxycarboxylic acid and a cationic surfactant in combination. This method can be applied to a titania sol. Inorganic oxides produced by the phase method are insufficiently dispersed, making adaptation difficult. (Patent Document 3)

  In recent years, a technique for improving mechanical properties by mixing such an inorganic oxide and a resin has attracted attention, for example, control of mechanical properties and optical properties of a transparent polyimide. However, since the transparent polyimide undergoes a heating step of 250 to 350 ° C. during the manufacturing process, a general resin-type dispersant, an inorganic oxide dispersion using a cationic activator, yellowing due to decomposition of the dispersant Accordingly, there has been a problem that transparency and mechanical properties of polyimide are impaired.

WO2007 / 138946 JP 2009-143974 A JP-A-2003-95657

  The present invention provides an inorganic oxide dispersion having excellent dispersion stability and high transparency irrespective of the addition amount of a dispersant being low, and a paint, a coating film and a film containing the inorganic oxide dispersion. The purpose is to do. Further, by using the inorganic oxide dispersion of the present invention, even at a high temperature of 300 ° C. or more, coloring is small (high heat resistance), and mechanical properties (thermal expansion properties) of coating films and films can be improved. With the goal.

That is, the present invention provides an inorganic oxide comprising an inorganic oxide, an amine represented by the following general formula A, an aliphatic hydroxy acid having a molecular weight of 200 or less, and a solvent having a relative dielectric constant of 18 or more. A material dispersion.
General formula A
(R ¹ represents an alkyl group having ² to 13 carbon atoms. R ² and R ³ each independently represent a hydrogen atom or an alkyl group having 2 to 13 carbon atoms.)

  The present invention also relates to the inorganic oxide dispersion, wherein the solvent is at least one selected from the group consisting of water, alcohol, γ-butyrolactone, and a nitrogen-containing organic solvent.

  The present invention also relates to a paint containing the inorganic oxide dispersion.

  The present invention also relates to a coating film formed using the inorganic oxide dispersion.

  The present invention also relates to a film formed using the inorganic oxide dispersion.

  According to the present invention, there is provided an inorganic oxide dispersion having excellent dispersion stability and high transparency irrespective of a low addition amount of a dispersant, and a paint, a coating film and a film containing the inorganic oxide dispersion. can do. In addition, by using the inorganic oxide dispersion of the present invention, even at a high temperature of 300 ° C. or more, coloring is small (high heat resistance), and the mechanical properties (thermal expansion properties) of coating films and films can be improved. it can.

<Inorganic oxide dispersion>
The inorganic oxide dispersion of the present invention comprises an inorganic oxide, an amine represented by the following general formula A, an aliphatic hydroxy acid having a molecular weight of 200 or less, and a solvent having a relative dielectric constant of 18 or more. And Hereinafter, the materials used for the inorganic oxide dispersion of the present invention will be described.

<Inorganic oxide>
As the inorganic oxide used for the inorganic oxide dispersion, an oxide of at least one of a metal element and Si can be used. It is possible to select an inorganic oxide according to physical properties required for a coating film, a film, and the like. For example, zirconia (ZrO ₂ ), titania (TiO ₂ ), silica (SiO ₂ ), alumina (Al ₂ O) ₃ ), iron oxide (Fe ₂ O ₃ ), copper oxide (CuO), zinc oxide (ZnO), yttria (Y ₂ O ₃ ), niobium oxide (Nb ₂ O 5), molybdenum oxide (MoO ₃ ), indium oxide ( In ₂ O ₃ ), tin oxide (SnO ₂ ), tantalum oxide (Ta ₂ O ₅ ), tungsten oxide (WO ₃ ), lead oxide (PbO), bismuth oxide (Bi ₂ O 3), ceria (CeO ₂ ), oxidation antimony _{(Sb 2 O 5, Sb 2} O 3) , and the like. The above-mentioned inorganic oxides can be used alone or as a mixture of two or more.

As for the particle diameter of the inorganic oxide, the average particle diameter is preferably in the range of 15 to 50 nm from the viewpoint of transparency.
Here, the average particle diameter is an arithmetic average of the particle diameters observed with a scanning electron microscope (SEM). In detail, it is a value obtained by observing the powder of the coating particles at a magnification of 20,000, selecting 100 arbitrary particles, and averaging the particle diameters of the particles. When the particle shape has a major axis and a minor axis, the average value of the major axis and minor axis lengths is defined as the particle diameter of the particle.

  Synthetic methods of inorganic oxides are roughly classified into three types: solid-phase method, liquid-phase method, and gas-phase method. Since a fine inorganic oxide can be obtained, it is preferable to use an inorganic oxide synthesized by a liquid phase method or a gas phase method. Particularly in the liquid phase method, a coprecipitation method in which precipitation is caused by a change in pH, addition of a solvent, etc. from a solution in which constituent ions of a substance to be synthesized are dissolved, a hydrolysis method in which particles are synthesized by hydrolyzing a metal alkoxide A solvothermal method for synthesizing substances and growing crystals by heating in a solvent under pressure, hydrolyzing a metal alkoxide to form a sol in which particles are dispersed in a colloidal form into a gel with no fluidity, There is a sol-gel method in which particles are obtained by heating.

  It is preferable to use particles obtained by baking the inorganic oxide at a high temperature of 250 ° C. or higher and stabilizing the crystal skeleton of the inorganic oxide from the viewpoint of improving mechanical properties. In particular, when the inorganic oxide dispersion is used as a binder when coating as a paint or a film, or when using a polyamic acid varnish as a binder, a curing temperature of 300 to 400 ° C. is required. The applied inorganic oxide is chemically stable, can suppress film shrinkage, and can achieve good mechanical property values without causing defects in the film due to dehydration or the like.

<Amine>
The amine used in the inorganic oxide dispersion contains an amine represented by the following general formula A.

  General formula A:

R ¹ represents an alkyl group having 2 to 13 carbon atoms. R ² and R ³ each independently represent a hydrogen atom or an alkyl group having 2 to 13 carbon atoms. By using the present amine, the inorganic oxide dispersion can be specifically dispersed, and high transparency can be achieved. Further, since the amine is hardly volatilized at room temperature, the composition as a dispersion is stable, and as a result, the stability over time is excellent.

<Hydroxy acid>
The hydroxy acid used for the inorganic oxide dispersion is an aliphatic hydroxy acid having a molecular weight of 200 or less. In particular, the ratio of the number of hydroxyl groups to the number of carboxyl groups in the molecular skeleton of hydroxy acid is more preferably 1 to 3 as carboxyl groups / hydroxy groups in order to maintain the transparency of the inorganic oxide for a long time. When polyimide or polyamic acid varnish is used as a binder when the inorganic oxide dispersion is used as a paint or a film, a curing temperature of 300 to 400 ° C. is required. By simultaneously using the amine and the hydroxy acid used in the present invention, not only can the transparency after curing be maintained, but also there is no adverse effect on coloring due to decomposition and physical properties.

  The addition amount of the amine and the hydroxy acid is preferably 1 part by mass to 50 parts by mass, more preferably 5 parts by mass to 30 parts by mass with respect to 100 parts by mass of the inorganic oxide. When the addition amount of the amine and the hydroxy acid is in the above range, the transparency of the inorganic oxide particles can be maintained for a long time, and the physical property value when a coating film or a film is formed is not adversely affected.

<Solvent>
The solvent used for the inorganic oxide dispersion is a solvent having a relative dielectric constant of 18 or more. Here, the relative permittivity is a ratio of the permittivity of a medium to the permittivity of a vacuum.

  The above-mentioned solvent is preferably water, alcohol, γ-butyrolactone, and a nitrogen-containing organic solvent because the dispersion stability of the inorganic oxide dispersion over time is maintained, and the fine dispersion of the dispersed particle diameter is better. , Γ-butyrolactone and a nitrogen-containing organic solvent are more preferred. Here, the nitrogen-containing organic solvent is a general term for solvents having nitrogen in the molecule, and examples thereof include N-methyl-2-pyrrolidone, dimethylacetamide, dimethylsulfoxide, dimethylformamide, and acetonitrile.

  γ-butyrolactone, and nitrogen-containing organic solvents are widely used as solvents for dissolving various polymers because they are easy to dissolve various polymers, but in particular, polyimide, or polyamic acid varnish, generally widely Since it is used, it is preferable when the inorganic oxide dispersion is mixed with polyimide or polyamic acid varnish and used.

<Dispersion method>
In preparing the inorganic oxide dispersion, a disperser generally used for the purpose of achieving high transparency can be used. For example, a disperser, a homomixer, a planetary mixer, `` CLEARMIX '' manufactured by M Technic Co., Ltd. PRIMIX “Filmix”, paint conditioner (Red Devil), ball mill, sand mill (Shinmaru Enterprises “Dino Mill”, etc.), attritor, pearl mill (Eirich “DCP Mill”, etc.), coball mill , Wet jet mills ("Genus PY" manufactured by Genus, "Starburst" manufactured by Sugino Machine Co., Ltd., "Nanomizer" manufactured by Nanomizer, etc.), "Clear SS-5" manufactured by M-Technic, and "Nara Machinery" And a dispersing machine such as a roll mill. One type of disperser may be used alone, or two or more types may be used in combination.

<Dispersion particle size>
Dispersion particle diameter of the inorganic oxide dispersion, paint, from the viewpoint of transparency at the time of film, the smaller the dispersion particle diameter, is preferable because light scattering in the visible light region is reduced, but suppresses thermal expansion of polyimide and the like When the inorganic oxide is added for the purpose, it is preferably in the range of 15 to 150 nm, more preferably 30 to 100 nm, in consideration of compatibility with transparency. The dispersed particle diameter is a particle diameter that becomes 50% when the volume ratio of particles having a small particle diameter is integrated in a volume particle size distribution using a particle size distribution meter of a dynamic light scattering method. is there.

<Inorganic oxide paint>
The inorganic oxide dispersion of the present invention, if necessary, can be coated on various substrates by adding a binder, a curing agent, a drying inhibitor, a chelating agent, a rheology control agent, and a silane coupling agent. It can be used as an inorganic oxide paint.

<Binder>
Binders can be selected according to the physical properties required for coatings, films, etc., for example, resins such as polyacryl, polycarbonate, polyester, polyamide, polyolefin, polyurethane, polyether, polyvinylidene fluoride, etc. In a solvent, or a dispersed emulsion. In particular, the inorganic oxide dispersion of the present invention, it is preferable to use polyamide varnish as a binder, particularly polyimide, or, by using a polyamic acid varnish as a binder, polyimide, or, at the general curing temperature of polyamic acid varnish At a certain temperature of 300 to 400 ° C., aliphatic hydroxy acids and amines are further volatilized, which not only maintains transparency but also improves mechanical properties.

<Inorganic oxide coating>
An inorganic oxide paint is applied on various substrates, and the solvent is dried by heating, and cured as necessary, so that the inorganic oxide paint can be used as an inorganic oxide coating film. The substrate can be selected according to the required physical properties, for example, polyacryl, polycarbonate, polyester, polyamide, polyolefin, polyurethane, polyether, polyvinylidene fluoride, resin such as polyethylene terephthalate, or Films, plates, molded products, and the like made of metals such as iron, stainless steel, copper, and aluminum, or inorganic oxides such as glass.

<Inorganic oxide film>
The inorganic oxide coating obtained by applying an inorganic oxide paint on a substrate having various peeling properties, drying the solvent by heating, and curing if necessary, is peeled from the substrate. Thereby, an inorganic oxide film can be obtained. The obtained inorganic oxide film may be, if necessary, a resin such as polyacryl, polycarbonate, polyester, polyamide, polyolefin, polyurethane, polyether, polyvinylidene fluoride, polyethylene terephthalate, or iron, stainless steel, copper, aluminum, etc. And a film such as an inorganic oxide such as glass or the like, and can be used as a laminated film.

<Transparency>
Transparency, the more transparent, the better, the total light transmittance of a coated plate coated with an inorganic oxide paint on the substrate, a coated plate coated on a varnish so that when coated with a varnish the same thickness when dried When calculated as a reference, it is preferably 95 to 100%, and more preferably 97 to 100%.

<Heat resistance>
In particular, with respect to a coating film using polyimide as a binder, and a film, it is preferable that a decrease in transparency due to coloring or the like is small at a curing temperature of about 300 to 400 ° C., and an inorganic oxide paint is applied to a substrate. The absolute value of the value obtained by subtracting the value of the total light transmittance after heating from the value of the total light transmittance before heating of the coated plate is preferably less than 1%, and more preferably less than 0.5%.

<Thermal expansion>
In particular, regarding a film using polyimide as a binder, by uniformly dispersing the inorganic oxide in the film, it is possible to lower the linear expansion coefficient indicating a dimensional change upon heating as compared to the binder alone. In particular, when alumina is used as the inorganic oxide, the coefficient of linear expansion becomes lower, which is preferable. The coefficient of linear expansion can be determined by applying a non-oscillatory load and measuring the deformation of the material as a function of temperature while varying the temperature of the material according to an adjusted program. If the thickness of the film is about 50 μm, it is preferable to determine from the deformation when a tensile stress is applied.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples as long as the gist is not exceeded. In Examples and Comparative Examples, "parts" and "%" mean parts by mass and% by mass, respectively, unless otherwise specified.
In this specification, Example 17 and Example 45 are reference examples.

<Inorganic oxide>
The inorganic oxides used in the examples and comparative examples are listed below.
AEROXIDE Alu C (alumina, manufactured by Evonik Degussa)
AEROSIL 200 (silica, Evonik Degussa)
PCS-60 (zirconia, manufactured by Shin Nippon Denko KK)
TTO-V-3 (titanium oxide, manufactured by Ishihara Sangyo Co., Ltd.)
NANOFINE 50A (Zinc oxide, manufactured by Sakai Chemical Industry Co., Ltd.)
Bayral Al-L40P (alumina sol, manufactured by Taki Chemical Co., Ltd.)

<Amine>
Triethylamine (tertiary amine, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
Tripropylamine (tertiary amine, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
Dibutylamine (secondary amine, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
Dihexylamine (secondary amine, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
Dioctylamine (secondary amine, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
Didodecylamine (secondary amine, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
Octylamine (primary amine, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
Dodecylamine (primary amine, manufactured by Tokyo Chemical Industry Co., Ltd.)
Stearylamine (primary amine)
Nissan cation 2-DB-800E (quaternary amine, nonvolatile content 80%, manufactured by NOF CORPORATION)
Nissan Cation MA (Primary amine acetate, 100% non-volatile content, manufactured by NOF Corporation)

<Aliphatic hydroxy acid>
Lactic acid (Fujifilm Wako Pure Chemical Industries, Ltd., molecular weight 90.08)
DL-malic acid (Molecular weight 134.09 manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
Citric acid (Mf. 192.12, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
Tartaric acid (Fujifilm Wako Pure Chemical Industries, Ltd., molecular weight 150.09)
Quinic acid (Mf. 192.17, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
12-hydroxystearic acid (manufactured by Ito Oil Co., Ltd., molecular weight 300.48)

<Aliphatic hydroxy acid ammonium salt>
Ammonium lactate (nonvolatile content 40%, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
Triammonium citrate (Fujifilm Wako Pure Chemical Industries, Ltd.)

<Aromatic hydroxy acid>
Salicylic acid (Fujifilm Wako Pure Chemical Industries, Ltd., molecular weight 138.12)
3,4,5-trihydroxybenzoic acid (Fujifilm Wako Pure Chemical Industries, Ltd., molecular weight 170.12)

<Solvent>
Purified water (dielectric constant 80.1)
N, N-dimethylsulfoxide (dielectric constant 48.9, manufactured by Mitsubishi Gas Chemical Co., Ltd.)
N, N-dimethylacetamide (dielectric constant: 38.9, manufactured by Mitsubishi Gas Chemical Co., Ltd.)
N-methyl-2-pyrrolidone (dielectric constant 32.0, manufactured by Mitsubishi Chemical Corporation)
γ-butyrolactone (dielectric constant: 18.3, manufactured by Mitsubishi Chemical Corporation)
Methanol (dielectric constant 33.1, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
Ethanol (dielectric constant 23.8, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
2-propanol (dielectric constant: 18.3, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
Methyl isobutyl ketone (Relative dielectric constant: 13.1, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
Ethyl lactate (Relative dielectric constant: 13.1, Fujifilm Wako Pure Chemical Industries, Ltd.)
Propylene glycol monomethyl ether acetate (relative permittivity 8.0, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)
Ethyl acetate (relative permittivity 6.0, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

<Resin type dispersant>
DisperBYK-102 (acidic dispersant, manufactured by BYK Japan KK)

<Binder>
SPIXAREA TP001 (Somar Co., Ltd., nonvolatile content 25% by weight)

<Preparation of inorganic oxide dispersion>
According to the composition shown in Table 1, the mixture was stirred and mixed so as to be uniform, and further dispersed in a sand mill for 5 hours using zirconia beads having a diameter of 0.1 mm, and then filtered through a filter having a pore diameter of 1 μm to obtain an inorganic oxide dispersion. Was obtained respectively. In Table 1, a number without a unit notation indicates a part, and a blank indicates that no compounding is performed.

<Preparation of inorganic oxide paint>
According to the composition shown in Table 2, the mixture was stirred and mixed so as to be uniform to obtain inorganic oxide paints. In Table 2, a number without a unit notation indicates a part, and a blank indicates that it is not blended.

[Evaluation]
The viscosity, dispersibility, and stability over time of the obtained inorganic oxide dispersion were evaluated by the following methods. Table 3 shows the results. The inorganic oxide paints and films prepared using the inorganic oxide dispersions were evaluated for transparency, heat resistance and thermal expansion by the following methods. Table 4 shows the results.

(viscosity)
The viscosity of the inorganic oxide dispersion was measured at 25 ° C. and 60 rpm using a BII type viscometer (manufactured by Toki Sangyo Co., Ltd.). Regarding the viscosity, the lower one is preferable from the viewpoint of handling, and the evaluation was made according to the following criteria.
：: 15 mPa · s or less (very good)
：: Exceeding 15 mPa · s, 50 mPa · s or less (good)
×: Exceeding 50 mPa · s (defective)

(Dispersion particle size)
The dispersion particle size of the inorganic oxide dispersion is determined by using a dynamic light scattering type particle size distribution meter (Microtrack UPA, manufactured by Nikkiso Co., Ltd.) When integrated, the particle diameter of 50% was measured. The samples used for the measurements were prepared in Examples 1 and 3 to 28 and Comparative Examples 1 to 15 by adding an arbitrary measurable amount to the solvent used for preparing the dispersion and using a bath-type ultrasonic device. And dispersed and adjusted. Regarding Example 2, an arbitrary measurable amount of the dispersion was added to ethanol, dispersed by a bath-type ultrasonic device, and adjusted. The dispersed particle diameter is preferably as small as possible from the viewpoint of transparency, and evaluated according to the following criteria.
：: 100 nm or less (very good)
：: 100 nm or more, 150 nm or less (good)
×: Over 150 nm (defective)

(Aging stability)
The stability over time of the inorganic oxide was determined by measuring the viscosity of a sample in which the inorganic oxide dispersion was allowed to stand at 50 ° C. for 7 days, and subtracting the value of the viscosity after standing from the value of the viscosity before standing. The value was evaluated as the rate of change in viscosity. The smaller the change rate of the viscosity, the better, and the evaluation was made according to the following criteria.
：: 5 mPa · s or less (very good)
○: Exceeding 5 mPa · s, 10 mPa · s (good)
×: Exceeding 10 mPa · s (defective)

(transparency)
The inorganic oxide paint was applied to a glass substrate of 10 cm × 10 cm using a doctor blade so that the film thickness after drying was 2 μm, and dried in an oven at 140 ° C. for 30 minutes to form a coating film. The binder was applied and dried in the same manner to form a coating film. Using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., NDH-2000), the total light transmittance of the obtained coating film was calculated based on the value of the inorganic oxide coating film based on the value of the glass plate coated with the binder. It was measured. The value of the total light transmittance is preferably as close to 100 as possible, and evaluated according to the following criteria.
：: 97% or more and 100% or less (very good)
：: 95% or more and less than 97% (good)
×: less than 95% (defective)

(Heat-resistant)
After the coating film used for the transparency evaluation was heated in an oven under a nitrogen atmosphere at 300 ° C. for 1 hour, the transparency was evaluated, and the value of the total light transmittance after heating was calculated from the value of the total light transmittance before heating. It was evaluated from the absolute value of the subtracted value. The smaller the change in the total light transmittance before and after heating, the higher the heat resistance. Therefore, the evaluation was made according to the following criteria.
A: Less than 0.5% (very good)
：: 0.5% or more and less than 1% (good)
×: 1% or more (defective)

(Thermal expansion)
The inorganic oxide coating was applied to a 250 μm-thick PET film using a doctor blade so that the film thickness after drying became 50 μm, and dried in an oven at 105 ° C. for 1 hour to form a coating film. This coating film was peeled from the substrate to obtain an inorganic oxide film. The inorganic oxide film was heated in an oven at 250 ° C. for 1 hour, processed into a test piece of 4.5 mm × 3.0 cm, and subjected to a tensile load using Q400EM (manufactured by TA Instruments). The coefficient of linear expansion was measured from the relationship between and the strain of the test piece. The binder was coated and dried in the same manner to form a film, and the coefficient of linear expansion was measured. The value obtained by subtracting the coefficient of linear expansion of the inorganic oxide film from the value of the coefficient of linear expansion of the film containing only the binder was evaluated according to the following criteria.
：: 10 ppm / ° C. or more (very good)
：: less than 10 ppm / ° C., 5 ppm or more (good)
×: less than 5 ppm / ° C (defective)

  As shown in Table 3, the dispersions of Examples 1 to 28 were all good in viscosity, dispersed particle diameter, and stability over time. In particular, with respect to Examples 1 to 8, 10 to 20, and 25 to 28, the results with time stability were even better. Further, as shown in Table 4, as paints and films, Examples 29 to 52 had good transparency and heat resistance, and Examples 29 to 36 and 38 to 52 were even better.

  The highly transparent inorganic oxide dispersion of the present invention can be widely applied to inorganic oxides added for the purpose of adjusting mechanical strength, optical properties, electric properties, etc., so that surface hardness adjustment, refractive index adjustment, infrared cut, antistatic It can be used for a wide range of applications such as coatings and films that require adjustment of the properties and thermal expansion properties.

Claims (4)

It comprises an inorganic oxide fired at 250 ° C or higher, an amine represented by the following general formula A, an aliphatic hydroxy acid having a molecular weight of 200 or less, and a solvent having a relative dielectric constant of 18 or more. A paint comprising an inorganic oxide dispersion and at least one binder selected from the group consisting of polyimide and polyamic acid.
General formula A


(R ¹ represents an alkyl group having ² to 13 carbon atoms. R ² and R ³ each independently represent a hydrogen atom or an alkyl group having 2 to 13 carbon atoms.)
The paint according to claim 1, wherein the solvent is at least one selected from the group consisting of water, alcohol, γ-butyrolactone, and a nitrogen-containing organic solvent. A coating film formed using the paint according to claim 1. A film formed using the paint according to claim 1.