JP2011173740A - Tin oxide fine particle, and dispersion liquid, coating liquid and resin composition containing the same - Google Patents

Abstract

A tin oxide fine particle having good conductivity is provided.
A tin oxide fine particle in which a second metal atom and a third metal atom are dissolved in tin oxide, wherein the second metal atom and the third metal atom are tungsten or zinc and are different from each other. Tin oxide fine particles satisfying the following atomic ratio.
0.88 ≦ Sn / (Sn + W + Zn) ≦ 0.999
0.001 ≦ second metal atom / (Sn + W + Zn) ≦ 0.07
0 ≦ third metal atom / (Sn + W + Zn) ≦ 0.05
0.90 ≦ (Sn + W + Zn) / all metal atoms ≦ 1.00
[Selection figure] None

Description

  The present invention relates to tin oxide fine particles, and a dispersion liquid, a coating liquid and a resin composition containing the same. More specifically, the present invention relates to a tin oxide fine particle having good conductivity, a dispersion containing tin oxide fine particles having good conductivity without containing indium-tin oxide (ITO), a coating liquid, and a resin composition. .

  BACKGROUND ART Conductive oxide powders mainly composed of indium-tin oxide (ITO) are actively used for transparent conductive films. As a method for producing a transparent conductive film from a conductive oxide powder, for example, a conductive oxide powder having a primary particle diameter of about 100 nm or less is dispersed in a solution containing a binder resin to produce a conductive paint. There is a method in which a conductive paint is applied to a substrate such as glass or plastic by a means such as application, printing, dipping, spin coating or spraying, and then drying.

The transparent conductive film has an anti-static function and an anti-dusting function for glass, plastic and the like, and is used for displays, window glass for measuring instruments, IC package circuits, clean room interior materials, various glasses, films and the like. The transparent conductive film is also used as a coating-type transparent electrode, an infrared shielding material, and the like.
As described above, the demand for transparent conductive films is expected to increase in the future, and the demand for conductive paints and conductive films that are excellent in conductivity and excellent in transparency is increasing with the expansion of the field of use.

  However, indium used for the transparent conductive film has a limited amount of resources, and ITO has come to be used as a transparent electrode of a liquid crystal display. As described above, ITO has an anxiety such as supply limitation, and development of an oxide conductive material that does not use indium oxide is urgently required.

Patent Document 1 discloses a white conductive powder having a coating layer of tin dioxide containing tungsten element on the surface of white inorganic pigment particles. Tin dioxide containing tungsten, which is a conductive component, is white, and the conductivity of the powder is as low as 7 × 10 ⁻² S / cm even when molded at a high pressure of 23 MPa.

  Patent Document 2 is an invention relating to a mixed sol of tin oxide and tungsten oxide, and tin oxide and tungsten oxide are separate components. Although there is disclosure that a coating film can be formed and that the coating film can be used for antistatic, it is not considered that tungsten is dissolved in tin oxide simply by making a coating film. Since there is no effect, it is considered that the conductivity is low.

JP 2002-179948 A JP-A-3-151038

An object of the present invention is to provide tin oxide fine particles having good conductivity.
An object of the present invention is to provide a dispersion, a coating liquid, and a resin composition containing tin oxide fine particles having good conductivity without containing ITO.

According to the present invention, the following tin oxide fine particles and the like are provided.
1. Tin oxide fine particles in which a second metal atom and a third metal atom are dissolved in tin oxide,
The second metal atom and the third metal atom are tungsten or zinc and are different from each other;
Tin oxide fine particles satisfying the following atomic ratio.
0.88 ≦ Sn / (Sn + W + Zn) ≦ 0.999
0.001 ≦ second metal atom / (Sn + W + Zn) ≦ 0.07
0 ≦ third metal atom / (Sn + W + Zn) ≦ 0.05
0.90 ≦ (Sn + W + Zn) / all metal atoms ≦ 1.00
2. 2. The tin oxide fine particles according to 1, wherein all the metal atoms contained in the tin oxide fine particles are substantially tin atoms, second metal atoms, and third metal atoms.
3. The tin oxide fine particles according to 1 or 2, having an average particle diameter of 1 to 500 nm.
4). The tin oxide fine particles according to any one of 1 to 3, wherein colorimetric values in the L ^* a ^* b ^* color system are 20 <L ^* <60, 0 <a ^* <10, and 0 <b ^* <20.
A tin oxide fine particle dispersion in which the tin oxide fine particles according to any one of 5.1 to 4 are dispersed in water, alcohol or an organic solvent.
A coating solution containing tin oxide fine particles obtained by adding an inorganic binder or an organic binder to the tin oxide fine particle dispersion described in 6.5.
A resin composition obtained by kneading the tin oxide fine particles according to any one of 7.1 to 4 with an organic resin.
A resin composition in which the tin oxide fine particle dispersion described in 8.5 is kneaded with an organic resin.
The electrically conductive film obtained by apply | coating the tin oxide fine particle containing coating liquid as described in 9.6.
A laminate comprising the conductive film according to 10.9.

According to the present invention, fine tin oxide particles having good conductivity can be provided.
ADVANTAGE OF THE INVENTION According to this invention, the dispersion liquid, coating liquid, and resin composition containing the tin oxide microparticles | fine-particles which have favorable electroconductivity even if ITO is not included can be provided.

It is a figure which shows the relationship between the applied pressure and resistance at the time of measuring the electrical conductivity of the microparticles | fine-particles obtained in Example 1. FIG. 4 is a powder X-ray diffraction measurement chart of fine particles obtained in Example 3. FIG.

The tin oxide fine particles of the present invention are tin oxide fine particles in which a second metal atom and a third metal atom are dissolved in tin oxide, and satisfy the following atomic ratio.
The second metal atom and the third metal atom are tungsten or zinc, and are different metal atoms, preferably the second metal atom is tungsten and the third metal atom is zinc.
0.88 ≦ Sn / (Sn + W + Zn) ≦ 0.999
0.001 ≦ second metal atom / (Sn + W + Zn) ≦ 0.07
0 ≦ third metal atom / (Sn + W + Zn) ≦ 0.05
0.90 ≦ (Sn + W + Zn) / all metal atoms ≦ 1.00
(In the above atomic ratio, Sn represents a tin atom, W represents a tungsten atom, and Zn represents a zinc atom.)

The oxide particles of the present invention preferably satisfy the following atomic ratio.
0.88 ≦ Sn / (Sn + W + Zn) ≦ 0.995
0.005 ≦ second metal atom / (Sn + W + Zn) ≦ 0.06
0 ≦ third metal atom / (Sn + W + Zn) ≦ 0.05
0.90 ≦ (Sn + W + Zn) / all metal atoms ≦ 1.00

When the atomic ratio of the second metal atom (second metal atom / (Sn + W + Zn)) is less than 0.001, the conductivity of the fine particles may be very low. On the other hand, when the atomic ratio of the second metal atom (second metal atom / (Sn + W + Zn)) exceeds 0.07, the conductivity of the fine particles may be very low.
When the atomic ratio of the third metal atom (third metal atom / (Sn + W + Zn)) exceeds 0.05, the conductivity of the fine particles may be lowered.
When the atomic ratio of tin atom, second metal atom, and third metal atom to all metal atoms ((Sn + W + Zn) / all metal atoms) is less than 0.90, the conductivity of the fine particles may be lowered.

The tin oxide fine particles of the present invention include the case where the third metal atom / (Sn + W + Zn) = 0. That is, the tin oxide fine particles of the present invention may not contain the third metal atom.
In this case, the tin oxide fine particles of the present invention satisfy the following atomic ratio.
0.88 ≦ Sn / (Sn + second metal atom) ≦ 0.999
0.001 ≦ second metal atom / (Sn + second metal atom) ≦ 0.07
0.90 ≦ (Sn + second metal atom) / all metal atoms ≦ 1.00
(The second metal atom is tungsten or zinc.)

The total metal atoms contained in the tin oxide fine particles of the present invention are preferably substantially only tin atoms, second metal atoms, and third metal atoms.
Note that “substantially” means that no elements other than impurities, which are inevitably included due to raw materials, manufacturing processes, and the like are included. Inevitable impurities are usually less than 100 ppm, preferably less than 50 ppm, particularly preferably less than 10 ppm.

The tin oxide fine particles of the present invention may contain other metal atoms as long as the second metal atom and the third metal atom are dissolved in the tin oxide and exhibit the effect as the fine particles.
The same applies to a resin composition, a conductive film, a laminate, and the like, which will be described later, obtained by the tin oxide fine particles of the present invention.
The tin oxide fine particles of the present invention include, in addition to tin, tungsten and zinc, magnesium, aluminum, silicon, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, gallium, germanium, yttrium, zirconium, niobium and molybdenum. , Palladium, silver, lanthanum, cerium, praseodymium, neodymium, hafnium and tantalum.

  The atomic ratio of each element contained in the tin oxide fine particles of the present invention is determined by X-ray fluorescence analysis (XRF) in which X-rays are used for excitation of inner-shell electrons and characteristic X-rays (fluorescence X-rays) from a sample are measured. Can be obtained by quantitative analysis of the contained elements.

When an absorption spectrum of X-rays by a substance is measured, a spectrum in which a discontinuous portion is generated is obtained, and the energy at which the discontinuity is generated is called an absorption edge. The absorption edge energy can be said to be the minimum energy required to emit fluorescent X-rays of the series (K, L...).
X-rays having energy higher than the absorption edge cause vacancies in the inner shell of atoms, and electrons transition from the outer shell. The energy difference is emitted as fluorescent X-rays. Since the energy of the inner shell is element specific, the wavelength of the fluorescent X-ray is also element specific. From this, the element constituting the measurement sample can be analyzed by experimentally obtaining the wavelength of the fluorescent X-ray of the measurement sample.

  For quantification in X-ray fluorescence analysis, prepare a standard sample with a known chemical composition and surface concentration similar to the measured (unknown) sample, obtain the relationship between the concentration of the element for analysis and the fluorescent X-ray intensity, and perform calibration. Create a line. Next, the fluorescence X-ray intensity from the unknown sample is measured, and the concentration is determined from the calibration curve.

The average particle size of the tin oxide fine particles of the present invention is not particularly limited as long as it is a size that can be dispersed in a solvent, but the average particle size is preferably 500 nm or less, more preferably 200 nm or less. By setting the average particle diameter of the tin oxide fine particles to 200 nm or less, the tin oxide fine particles can also be used in products (for example, touch panels) that require transparent conductivity.
The lower limit of the average particle diameter of the tin oxide fine particles is not particularly limited as long as it is a size that can be dispersed in a solvent, and examples thereof include 1 nm.
In addition, the average particle diameter of the above-mentioned tin oxide fine particles can be calculated from the BET surface area.

The tin oxide fine particles of the present invention preferably have color measurement values in the L ^* a ^* b ^* color system of 20 <L ^* <60, 0 <a ^* <10, 0 <b ^* <20, and more preferably. Are 35 <L ^* <55, 0 <a ^* <5, 5 <b ^* <15. If the values of L ^* , a ^* and b ^* are not within the range, the conductivity of the tin oxide fine particles may be very low.
Pure tin oxide often exhibits white color, but the tin oxide fine particles of the present invention are colored and can be electrically conductive because tungsten and / or zinc are in solid solution.

The tin oxide fine particles of the present invention preferably have an electric conductivity of 10 ⁻² or more and 10 ² or less S / cm when a pressure of 9.6 MPa is applied.
The electrical conductivity can be measured while applying pressure using, for example, a powder resistance measurement system MCP-PD51 type (manufactured by Mitsubishi Chemical Analytech Co., Ltd.).

The tin oxide fine particles of the present invention can be produced by any of the following methods (1) to (3), preferably the method (1). By using the precipitation method, tin oxide fine particles having a uniform material can be obtained.
(1) A tin, tungsten, and zinc content is prepared from a solution in which each metal salt of tin, tungsten, and zinc is dissolved by a precipitation method, and the prepared content is an inert gas having an oxygen concentration of 0.1% by volume or less. Alternatively, heat treatment is performed under a reducing gas.
(2) A suspension containing each compound of tin, tungsten and zinc is prepared, and the prepared suspension is supplied into a thermal plasma to form a vaporized mixture, and the vaporized mixture is cooled. The tin oxide fine particles obtained by cooling may be further heat-treated in an inert gas or a reducing gas having an oxygen concentration of 0.1% by volume or less.
(3) A tungsten compound and a zinc compound are added to and mixed with the tin oxide fine particles, and the resulting mixture is heat-treated in an inert gas or a reducing gas having an oxygen concentration of 0.1% by volume or less.

Hereinafter, the case where the tin oxide fine particles of the present invention are produced using the above (1) precipitation method will be described.
Examples of tin, tungsten and zinc metal salts include nitrates, chlorides, acetates, alkoxides, tungstates, and the like. Examples of the alkoxide include methoxide and ethoxide.

The metal salt can be dissolved in an organic solvent such as water, alcohol or oxygen-containing compound.
Examples of the alcohol include methanol, ethanol, 2-propanol, 2-methoxyethanol, and 2-ethoxyethanol.
Examples of the oxygen-containing compound include esters such as ethyl acetate, and carboxylic acids such as acetic acid and propionic acid.

  The concentration of the metal salt in the metal salt solution is preferably in the range of 0.001 mol / l to 10 mol / l. When the concentration is less than 0.001 mol / l, productivity may be deteriorated. On the other hand, at a high concentration exceeding 10 mol / l, the stirring of the precipitation solution may be difficult.

Precipitating agents used in the precipitation method are, for example, alkaline solutions such as ammonium hydroxide, sodium hydroxide, ammonium carbonate, sodium carbonate, ammonium hydrogen carbonate, sodium hydrogen carbonate; organic acids such as oxalic acid, formic acid, ammonium oxalate, and organic acids Salt; and urea which decomposes when heated to generate ammonia.
The precipitant is preferably ammonium carbonate, ammonium hydrogen carbonate, sodium carbonate, sodium hydrogen carbonate, oxalic acid, ammonium oxalate, or urea in that a uniform precipitate is easily formed.

The amount of the precipitating agent is usually 50% or more of the chemical equivalent required for each of the above metal salts to become a compound such as hydroxide or oxalate, and preferably the washing time due to residual alkali ions or the like. From the viewpoint of shortening, the chemical equivalent is 80% to 2000%.
When the addition amount of the precipitant is less than 50% of the chemical equivalent, the composition of the precipitate may be different from the solution composition.

The formation temperature of the precipitate is usually from the freezing point of the solvent used to the boiling point of the solvent, and preferably from the freezing point of the solvent used + 5 ° C. to the boiling point of the solvent.
After the formation of the precipitate, the aging may be performed for several minutes to about 100 hours by raising the temperature from the same temperature as the formation of the precipitate to the boiling point of the solvent at normal pressure or 300 ° C. under pressure. By aging, the precipitate can be easily filtered, and a precipitate that is a more complete compound such as hydroxide or oxalate can be obtained.

The obtained compound (precipitate) is preferably separated from the solution by means of filtration, centrifugation, decantation, etc., and then washed with water or solvent to remove unnecessary ions and the like. The removal of unnecessary ions or the like can be taken as a guide, for example, that the electric conductivity of the solvent used for cleaning is 0.5 mS or less.
Examples of the solvent used in the solvent washing include alcohols such as ethanol and 2-propanol, and ethers such as tetrahydrofuran (THF).

After washing, water and solvent are removed by drying at 50 to 400 ° C. for 30 minutes to 100 hours. After the drying, the obtained compound may be converted into an oxide by further heat treatment, for example.
This heat treatment may be the same step as the heat treatment described later, but may be a preliminary heat treatment for removing water and solvent more completely. In the case of preliminary heat treatment, it is usually performed at about 200 to 800 ° C. In the case of preliminary heat treatment, it is not necessary to perform heat treatment under an inert gas.

The compound obtained by the precipitation method is heat-treated to form an oxide. By performing the heat treatment, the crystallinity of the compound can be improved and the conductivity can be improved.
When the heat treatment is performed at a high temperature, since the grain growth is severe, it is preferably performed in a short time. On the other hand, when the heat treatment is performed at a low temperature, the grain growth is suppressed, but the reaction proceeds slowly. For this reason, when the heat treatment is performed at a low temperature, the conductivity can be improved by performing the heat treatment for a longer time.

The heat treatment conditions such as the heat treatment temperature and the heat treatment time may be determined in consideration of the particle size required for the tin oxide fine particles and the required degree of conductivity.
For example, the heat treatment temperature is preferably 1300 ° C. or lower. When the heat treatment temperature exceeds 1300 ° C., the grain growth is particularly intense, and it may be difficult to produce fine particles. The heat treatment temperature is usually 200 ° C. or higher, preferably 300 ° C. or higher, as in the case of the preliminary heat treatment described above.

The heat treatment time is usually a short time of about several hours at a high temperature, and about several tens of hours or less is sufficient even at a low temperature. For example, when the heat treatment temperature is 1000 ° C. or more, the heat treatment time is preferably 10 minutes or less. When the heat treatment temperature is 500 to 1000 ° C., the heat treatment time is preferably 5 hours or less. When the heat treatment temperature is 500 ° C. or less, the heat treatment time is preferably about several tens of hours or less.
Grain growth is high at high temperatures, so heat treatment in a short time is preferable. Grain growth is suppressed at low temperatures, but the solid-phase reaction is slow, so a longer heat treatment was performed to improve conductivity. Is preferred.

The heat treatment is usually performed under an inert gas or a reducing gas.
As the inert gas, nitrogen, helium, argon or the like can be used, and nitrogen or argon is preferable from the viewpoint of availability. The reducing gas is an organic substance such as hydrogen, carbon monoxide, or alcohol, and may be diluted with the above-described inert gas.
The oxygen concentration of the inert gas or reducing gas is usually 0.1% by volume or less, preferably 0.05% by volume or less. If the oxygen concentration exceeds 0.1% by volume, the conductivity may decrease. The ratio of the reducing gas to the inert gas (reducing gas / inert gas) is preferably 0.001 or more in volume ratio, and more preferably 10 or less because the reduction proceeds too much and the metal precipitates.

  The implementation of the heat treatment under an inert gas or a reducing gas is not particularly limited as long as the conditions capable of filling or circulating the gas and maintaining the inside of the furnace in a gas atmosphere are secured. For example, using an electric furnace, a rotary kiln, or the like. Can be implemented.

The tin oxide fine particles of the present invention can be obtained by crushing the heat-treated compound.
Crushing can be performed by dry pulverization using a mechanical pulverization method such as a planetary ball mill or a jet mill, whereby oxide fine particles having a smaller particle diameter can be obtained.

The tin oxide fine particles of the present invention thus obtained have a pattern close to the peak of the rutile type tin oxide when the powder X-ray diffraction measurement is performed because the second metal and the third metal are in solid solution in the tin oxide. Is obtained.
When powder X-ray diffraction measurement is performed using a copper tube (λ = 0.154 nm), the peak top 2θ / deg of the “main peak” of the tin oxide fine particles of the present invention is preferably 26.00 ° ±. 1.00 °, 33.88 ° ± 1.00 °, 51.78 ° ± 0.80 °, more preferably 26.00 ° ± 0.80 °, 33.88 ° ± 0.80 ° 51.78 ° ± 0.70 °, and more preferably 26.00 ° ± 0.50 °, 33.88 ° ± 0.50 °, and 51.78 ° ± 0.40 °.
The “main peak” refers to three peaks, the peak having the highest 2θ / deg peak obtained by the X-ray diffraction measurement, the highest peak, the second highest peak, and the third highest peak.

The tin oxide fine particles of the present invention can be made into a tin oxide fine particle dispersion by dispersing them in water, alcohol or an organic solvent.
The tin oxide fine particles used in the dispersion may be subjected to various surface treatments, for example, a hydrophilic treatment or a non-hydrophilic treatment, and the solvent of the dispersion is appropriately selected depending on the state of the surface treatment.

As the solvent for the dispersion, water, methanol, ethanol, 2-propanol, 1-propanol, 1-methoxy-2-propanol, 2-methoxy-1-propanol, 1-ethoxy-2-propanol, 2-ethoxy-1 -Propanol, 2-methoxyethyl acetate, 2-methoxy-1-propyl acetate, 1-methoxy-2-propyl acetate, 2-ethoxyethyl acetate, 2-butoxyethyl acetate, tetrahydrofurfuryl alcohol, propylene carbonate, N, N -Dimethylformamide, N-methylformamide, N-methylpyrrolidone, 2-ethoxyethanol, 2-butoxyethanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone, methyl acetate, ethyl acetate, propyl acetate, acetic acid Chill, can be exemplified toluene, xylene, ethylbenzene, isophorone, cyclohexanone, 2-ethoxyethanol, 2-butoxyethanol and the like.
In addition, when using a dispersion liquid for an electroconductive coating material, it is preferable to use the solvent which can melt | dissolve the binder used for an electroconductive coating material easily.

  In the dispersion containing tin oxide fine particles of the present invention, the content of the tin oxide fine particles is preferably 1% by weight or more and 80% by weight or less.

In addition, if necessary, the tin oxide fine particle dispersion of the present invention includes an antifoaming agent, a thixotropic agent, a surfactant, a pigment wetting agent, a dispersing agent, an ultraviolet absorber, a light stabilizer, an antioxidant, and the like. (Heat) stabilizers, preservatives, fungicides, algae inhibitors, anticorrosion / rust inhibitors, dyes, pigments and other additives may be included.
The method of dispersing these additives is not particularly limited as long as it is a method of uniformly dispersing in the medium. For example, a bead mill, a ball mill, a sand mill, a paint shaker, an ultrasonic homogenizer or the like is used. Can be dispersed.

By adding an inorganic binder or an organic binder to the tin oxide fine particle dispersion of the present invention, a tin oxide fine particle-containing coating solution can be obtained.
The tin oxide fine particle-containing coating solution can be suitably used as a material for forming an antistatic film, a transparent electrode, a heat ray shielding film, and the like.

The binder added to the tin oxide fine particle dispersion is not particularly limited as long as it is a binder capable of forming a film having excellent durability.
Examples of the organic binder include acrylic resins such as methacrylic resins, amino resins such as polyacetylene resins and melamine resins, polyamide resins, polyimide resins, polyamideimide resins, polyethylene resins, polycarbonate resins, and polyurethane resins. Polyester resins such as alkyd resins, epoxy resins, polystyrene resins, ABS resins, polyamine sulfone resins, polyether sulfone resins, vinyl chloride resins, vinylidene chloride resins, vinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins, Silicone resin, fluorine resin, polyphenylene oxide resin, polypyrrole resin, polythiophene resin, polyaniline resin, polyacetylene resin, UV curable resin, diacetyl cellulose It can be exemplified fine cellulose derivatives triacetyl cellulose and the like.
These binders can be used alone or in combination of two or more.
As the inorganic binder, metal alkoxides of silicon, zirconium, titanium, or aluminum, partial hydrolysis-condensation products thereof, and organosilazanes can be used.

The mixing ratio of each component in the coating liquid is not particularly limited, and examples thereof include a mixing ratio in which tin oxide fine particles are 1 to 80% by weight, binder is 1 to 25% by weight, and the solvent is the balance.
By setting the coating liquid to this blending ratio, a transparent conductive film having a surface resistance value of 1 × 10 ¹⁰ Ω / □ or less, a total light transmittance of 80% or more, and a haze value of 15% or less can be easily obtained.

  The coating liquid of the present invention may optionally contain a curing agent such as a crosslinking agent, a curing catalyst such as a curing aid, a plasticizer, an antifoaming agent / leveling agent, a thixotropic agent, a matting agent, a surfactant, Flame retardants, pigment wetting / dispersing agents, lubricants, UV absorbers, light stabilizers, antioxidants, other (thermal) stabilizers, antiseptics, fungicides, algae inhibitors, anticorrosion / rust inhibitors, dyes, An additive such as a pigment may be included.

The production method of the coating liquid of the present invention is not particularly limited as long as the tin oxide fine particles are uniformly dispersed in the coating liquid. For example, bead mill, ball mill, sand mill, paint shaker, super Examples thereof include a method using a sonic homogenizer, a triple roll or the like.
In addition, a coating liquid can be produced at a time by adding a binder and other additives simultaneously with the preparation of the above dispersion.

The resin composition of the present invention can be obtained by kneading the tin oxide fine particles of the present invention with an organic resin. By making the resin composition of the present invention into a molten or softened state and molding it into a film or molded body (eg, sheet, panel, fiber, rod, tube, three-dimensional molded article, etc.) by a conventional method, the molded body is It can be suitably used as antistatic, transparent electrode, heat ray shielding and the like.
As the molding method, inflation method film molding, extrusion molding, press molding or the like can be adopted.

In the case of the resin composition of the present invention in which tin oxide fine particles are dispersed in a softened or molten organic resin, an organic resin used for producing a transparent film and a transparent molded body can be used.
Examples of the organic resin include acrylic resins such as methacrylic resins, amino resins such as polyacetylene resins and melamine resins, polyamide resins, polyimide resins, polyamideimide resins, polyethylene resins, polycarbonate resins, and polyurethane resins. Polyester resins such as alkyd resins, epoxy resins, polystyrene resins, ABS resins, polyamine sulfone resins, polyether sulfone resins, vinyl chloride resins, vinylidene chloride resins, vinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins, Silicone resin, fluorine resin, polyphenylene oxide resin, polypyrrole resin, polythiophene resin, polyaniline resin, polyacetylene resin, UV curable resin, diacetyl cellulose and triacetyl Cellulose derivatives such as cetyl cellulose.
The resin to be used is not limited to such a general-purpose resin, and various functional resins such as a heat resistant resin and a weather resistant resin can also be used.

  The content of the organic resin (amount as a solid content) in the resin composition of the present invention is, for example, 25 to 100,000 parts by weight, preferably 25 to 50,000 parts by weight with respect to 100 parts by weight of tin oxide fine particles. Is within the range.

What is necessary is just to perform the manufacturing method of a resin composition by the arbitrary methods which can disperse | distribute powder in molten or softening resin. For example, tin oxide fine particles, or tin oxide fine particle dispersion in a softened organic resin using a kneading roll, tin oxide fine particles or tin oxide fine particles in a molten resin in a suitable melt mixer such as an extruder A method of mixing the dispersion can be employed.
Also in this resin composition, one or more conventional additives such as a dispersant, a coupling agent, and a wetting agent can be blended.

A conductive film is obtained by applying the tin oxide fine particle-containing coating solution of the present invention. Specifically, the conductive film can be obtained by applying the tin oxide fine particle-containing coating solution of the present invention to the surface of a substrate such as glass or plastic, drying and curing, and forming a film on the surface of the substrate. it can.
Moreover, the laminated body of this invention is a laminated body containing the board | substrate and the electrically conductive film of this invention. The conductive film may be directly laminated on the substrate, or may be laminated on another layer on the substrate.

In order to apply the tin oxide fine particle-containing coating solution onto the surface of the substrate, a known method can be used, and examples thereof include spin coating, dip coating, spray coating, flow coating, bar coating, and gravure coating. The drying temperature is not particularly limited as long as the solvent of the coating solution is volatilized.
The conductive film (or laminate) may be formed by forming another film (intermediate film) on the substrate and applying a coating solution containing tin oxide fine particles to the film surface. The other film may be a single layer or a multilayer.

  Examples of the plastic film on which the tin oxide fine particle-containing coating solution is applied include a polyethylene terephthalate film, a polyethylene naphthalate film, a polymethyl methacrylate film, a polycarbonate film, a triacetyl cellulose film, a polyarylate film, and a polyethersulfone film. In particular, a polyethylene terephthalate (hereinafter abbreviated as PET) film is preferably used.

The plastic film is preferably transparent.
The thickness of the plastic film is preferably 25 μm or more and 250 μm or less, more preferably 50 μm or more and 200 μm or less.
If the thickness is less than 25 μm, the film rigidity is lowered and handling may be difficult. On the other hand, if it exceeds 250 μm, the film rigidity is increased, and handling becomes difficult and at the same time, there is a possibility that it becomes economically disadvantageous.

In particular, when an aromatic polyester film is used as the plastic film, an aromatic polyester film provided with an easy-adhesion layer by anchor coating is preferably used in order to improve the adhesion to the coating layer.
The easy adhesion layer may be formed after the transparent plastic film substrate is manufactured, or may be formed in-line when the transparent plastic film substrate is manufactured.

Examples of the anchor coating agent include aliphatic polyester, alicyclic polyester, acrylic ester, polyurethane, polyethyleneimine, silane coupling agent, and mixtures and copolymers thereof.
The thickness of the anchor coat layer is preferably 0.05 to 1.0 μm. If the thickness is less than 0.05 μm, sufficient adhesiveness may not be obtained, and if it is greater than 1.0 μm, the adhesive effect may be saturated.

The surface resistance value of the coated layer surface of the laminated plastic film is preferably 10 ¹⁰ Ω / □ or less in order to exhibit antistatic properties.

The thickness of the conductive film (after drying) is preferably 0.03 μm or more and 50 μm or less, more preferably 0.05 μm or more and 50 μm or less, and further preferably 0.07 μm or more and 8 μm or less.
If the thickness is less than 0.03 μm, the conductivity may not be sufficient. On the other hand, if the thickness exceeds 50 μm, the film may be easily curled.

  When no further layer is formed on the surface opposite to the substrate of the conductive layer (conductive film), a flat surface can be obtained by making the thickness of the conductive layer larger than the particle size of the oxide fine particles. it can. Moreover, a flat surface can be obtained by making the sum of the thickness of each layer laminated | stacked on an opposite surface with respect to the board | substrate of a conductive layer larger than the particle size of oxide microparticles | fine-particles.

By forming a film made of a metal alkoxide of silicon, zirconium, titanium, or aluminum, or a partially hydrolyzed polycondensation product thereof on the conductive layer, the binding force to the base material of the conductive layer and the hardness of the conductive layer The weather resistance can be further improved.
The conductive layer obtained from the dispersion containing no binder has a film structure in which only tin oxide fine particles are deposited on the substrate. The film is still conductive, but a coating liquid containing a metal alkoxide of silicon, zirconium, titanium, or aluminum or a partially hydrolyzed polycondensation product thereof and an inorganic binder or a resin binder is further coated on the film. To form a multilayer film. By doing so, the coating liquid component fills the gap in which the conductive fine particles of the conductive layer in the lower layer are deposited, so that the haze of the conductive layer is reduced and the visible light transmittance is improved. The binding property of the fine particles to the base material is improved.

When the coating solution contains an inorganic binder, the heating temperature of the substrate after application of the coating solution containing the metal alkoxide or its hydrolysis polymer is less than 100 ° C., and the alkoxide or its hydrolysis polymer contained in the coating film is less than 100 ° C. The polymerization reaction often remains incomplete, and water and organic solvents remain in the film and cause a decrease in the visible light transmittance of the film after heating. Heating above the boiling point of the solvent in the liquid.
When the coating solution contains a resin binder, it may be cured according to the respective curing method. For example, an ultraviolet curable resin may be appropriately irradiated with ultraviolet rays. If it is a room temperature curable resin, it may be left as it is after application. For this reason, it can be applied to existing window glass and the like on site.

The conductive film or laminate produced by applying the tin oxide fine particle-containing coating solution of the present invention on glass or polymer can be suitably used as an antistatic film, a heating element, a transparent electrode, or the like.
The conductive film or laminate of the present invention has an effect of shielding infrared rays having a wavelength of 1000 nm or more because the carrier concentration of the tin oxide fine particles is as high as 10 ¹⁹ to 10 ²¹ cm ⁻³ . Therefore, the electrically conductive film and laminated body of this invention can be used conveniently as a heat ray shielding film, a heat ray shielding member, etc.

Evaluation in Examples and Comparative Examples was performed by the following method.
[Average particle diameter of fine particles (dBET)]
From the specific surface area (Sm ² / g) of tin oxide fine particles and the density of tin oxide (6.99 g / cm ³ ) measured at a pretreatment temperature of 200 ° C. for 1 hour with BELSORP-mini II (manufactured by Nippon Bell Co., Ltd.), The average particle size of the fine particles was determined based on dBET = 6000 / S / 6.99 (nm).
[Electric conductivity of fine particles (σ)]
Powder resistance measurement system MCP-PD51 (Mitsubishi Chemical Analytech Co., Ltd.) was used to measure the electrical conductivity by the 4-probe method while applying pressure to fine particles, and a pressure of 9.6 MPa was applied. Was defined as the electrical conductivity of the fine particles.
[Chromaticity of fine particles]
Using an SE-6000 spectral color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd.), the chromaticity of the L ^* a ^* b ^* color system of fine particles was measured.
[Composition analysis of fine particles]
The fine particles were molded into a pellet shape having a diameter of 10 mm, and quantitatively analyzed using a wavelength dispersive X-ray fluorescence analyzer ZSX101e (manufactured by Rigaku Corporation) to measure the composition.
[Powder X-ray diffraction measurement of fine particles]
Powder X-ray diffraction measurement of the fine particles was performed using Minitube II (manufactured by Rigaku Corporation) using a copper tube at a scanning speed of 2 ° / min.
[Average particle size (dBET)]
Using Zetasizer Nano ZS (Malvern), the average particle size of the fine particles in the dispersion was measured by a dynamic light scattering method.
[Total light transmittance and haze value]
Based on ASTM D 1003, the total light transmittance and haze value of the conductive film were measured using a haze meter NDH5000 (manufactured by Nippon Denshoku Co., Ltd.).
[Surface resistance value]
The surface resistance value of the electrically conductive film was measured based on JIS-K7194 using Hiresta-UP MCP-T610 (Mitsubishi Chemical Analytech Co., Ltd.).
[Spectral spectrum]
Using a spectrophotometer MP-3100 (manufactured by Shimadzu Corporation), the spectrum of the conductive film was measured in the range of 400 to 2200 nm.

Example 1
Weight of stannic chloride pentahydrate (manufactured by Wako Pure Chemical Industries, Ltd., SnCl ₄ · 5H ₂ O) and ammonium paratungstate (manufactured by Wako Pure Chemical Industries, Ltd., (NH ₄ ) ₁₀ shown in Table 1 W ₁₂ and O ₄₁ · _5H 2 O) was dissolved in ion-exchanged water 1.7L to prepare a solution a. While stirring at room temperature, this solution A was dropped into an aqueous solution (solution B) in which ammonium carbonate (Wako Pure Chemical Industries, Ltd., (NH ₄ ) ₂ CO ₃ ) having the weight shown in Table 1 was dissolved, over 10 minutes. did. Thereafter, stirring was continued for 30 minutes, and the solution and the precipitate formed were separated by centrifugation. The operation of washing the precipitate with water by adding ion-exchanged water to the precipitate and stirring, and then performing centrifugation was repeated three times. The precipitate was dried at 80 ° C. for 12 hours, then calcined in air at 200 ° C. for 30 minutes, and further heat-treated at 650 ° C. for 30 minutes in a nitrogen atmosphere to obtain tin oxide fine particles.
Table 1 shows the results of evaluating the physical properties of the obtained fine particles.
Further, FIG. 1 shows the relationship between applied pressure and resistance when the electrical conductivity of the obtained fine particles was measured. As can be seen from FIG. 1, it can be seen that the tin oxide fine particles of the present invention have high conductivity without applying high pressure.

Example 2
Stannic pentahydrate chloride weight shown in Table 1 in the preparation of solution A, ammonium paratungstate and zinc nitrate hexahydrate (manufactured by Wako Pure Chemical Industries, _{Ltd., Zn (NO 3) 2 ·} 6H Fine particles were prepared and evaluated in the same manner as in Example 1 except that ₂ O) was used and ammonium carbonate having the weight shown in Table 1 was used for preparing Solution B. The results are shown in Table 1.

Example 3
The weight of stannic chloride pentahydrate, ammonium paratungstate and zinc nitrate hexahydrate shown in Table 1 was used for the preparation of Solution A, and the weight of ammonium carbonate shown in Table 1 was used for the preparation of Solution B. Fine particles were prepared and evaluated in the same manner as in Example 1 except that they were used. The results are shown in Table 1.
Further, powder X-ray diffraction measurement was performed on the obtained fine particles. The results are shown in FIG. In FIG. 2, pattern 1 is a powder X-ray diffraction pattern of the fine particles of Example 3, pattern 2 is a diffraction pattern of rutile tin oxide (SnO ₂ ) calculated from the crystal structure, and pattern 3 is a monoclinic crystal calculated from the crystal structure. The diffraction pattern of the system tungsten oxide (WO ₃ ) and the pattern 4 are the diffraction pattern of wurtzite zinc oxide (ZnO) calculated from the crystal structure. As can be seen from FIG. 2, only the tin oxide peaks are observed from the powder X-ray diffraction measurement of the fine particles (the main peaks are 26.16 °, 33.88 °, 51.84 °), and tungsten and zinc are added to the tin oxide. It can be seen that is dissolved.

Example 4
The weight of stannic chloride pentahydrate, ammonium paratungstate and zinc nitrate hexahydrate shown in Table 1 was used for the preparation of Solution A, and the weight of ammonium carbonate shown in Table 1 was used for the preparation of Solution B. Fine particles were prepared and evaluated in the same manner as in Example 1 except that they were used. The results are shown in Table 1.

Example 5
Example 1 except that the weight of stannic chloride pentahydrate and ammonium paratungstate shown in Table 1 was used for the preparation of Solution A, and the weight of ammonium carbonate shown in Table 1 was used for the preparation of Solution B. Similarly, fine particles were prepared and evaluated. The results are shown in Table 1.

Example 6
Example 1 except that the weight of stannic chloride pentahydrate and ammonium paratungstate shown in Table 1 was used for the preparation of Solution A, and the weight of ammonium carbonate shown in Table 1 was used for the preparation of Solution B. Similarly, fine particles were prepared and evaluated. The results are shown in Table 1.

Comparative Example 1
Fine particles were prepared in the same manner as in Example 1 except that stannic chloride pentahydrate having the weight shown in Table 1 was used for preparing Solution A and ammonium carbonate having the weight shown in Table 1 was used for preparing Solution B. Prepared and evaluated. The results are shown in Table 1.

Comparative Example 2
The weight of stannic chloride pentahydrate, ammonium paratungstate and zinc nitrate hexahydrate shown in Table 1 was used for the preparation of Solution A, and the weight of ammonium carbonate shown in Table 1 was used for the preparation of Solution B. Fine particles were prepared and evaluated in the same manner as in Example 1 except that they were used. The results are shown in Table 1.

Comparative Example 3
100 g of rutile titanium dioxide (CR-EL, manufactured by Ishihara Sangyo Co., Ltd.) was dispersed in pure water to make a 1 L aqueous suspension and heated to 70 ° C. This aqueous suspension, stannate solution A and sodium tungstate to the stannic pentahydrate 34.9g was dissolved in 3N hydrochloric acid 250mL chloride (manufactured by Wako Pure Chemical Industries, _Ltd., Na _{2 WO} 4 · 2H 2 O) Alkaline solution B in which 1.65 g was dissolved in 250 mL of 5N sodium hydroxide solution was simultaneously added dropwise to adjust the pH of the suspension to 2 to 3.
After completion of the dropping, the suspension was filtered and washed, and dried at 110 ° C. for 8 hours. The obtained dried product was heat-treated at 650 ° C. for 1 hour in a nitrogen gas stream to obtain fine particles.
The obtained fine particles were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 7
4.0 g of fine particles prepared in Example 1, 0.4 g of Dispersbyk-180 (manufactured by Big Chemie) as a dispersant, and 35.6 g of propylene glycol monomethyl ether acetate were added to a bead mill (bead diameter: 0.1 mm) made of zirconia. And crushed at 1500 rpm for 3 hours.
After crushing, the beads were removed to obtain a tin oxide fine particle dispersion of propylene glycol monomethyl ether acetate. The average particle diameter of the tin oxide fine particles in this dispersion was 90 nm.
0.25 g of NK polymer MK-100IC (manufactured by Shin-Nakamura Chemical Co., Ltd., special acrylic resin) was added as a binder resin to 10 g of the prepared dispersion and stirred for 30 minutes to obtain a coating solution.
The prepared coating solution was applied onto a glass substrate with a bar coater (No. 3) at room temperature, and heat-treated at a temperature of 200 ° C. for 35 minutes to obtain a thin film.
As a result of evaluating the obtained thin film, the total light transmittance was 89.7%, the haze value was 1.2%, the surface resistance value was 8.2 × 10 ⁴ Ω / □, and both transparency and conductivity were obtained. I found it expensive.

Example 8
A tin oxide fine particle dispersion was prepared in the same manner as in Example 7, except that 4.0 g of the fine particles prepared in Example 2, 0.6 g of Disperbyk-2090 (manufactured by Big Chemie), and 35.4 g of propylene glycol monomethyl ether acetate were used. Prepared. The average particle diameter of the tin oxide fine particles in this dispersion was 75 nm.
A thin film was formed and evaluated in the same manner as in Example 7 using 10 g of the prepared dispersion.
The obtained thin film has a total light transmittance of 90.2%, a haze value of 1.0%, a surface resistance value of 9.7 × 10 ⁴ Ω / □, and high transparency and conductivity. I understood.

Example 9
2.0 g of the fine particles prepared in Example 2, 0.4 g of Disperbyk-2000 (manufactured by Big Chemie Co., Ltd.), and 37.6 g of ethanol were charged into a zirconia bead mill (bead diameter: 0.1 mm) and 2.5 rpm at 1500 rpm. Crushed for hours. After crushing, the beads were removed to obtain a dispersion of tin oxide fine particles of ethanol. The average particle diameter of the tin oxide fine particles in this dispersion was 85 nm.
To 1 g of the prepared dispersion, 0.1 g of PVB1000 (manufactured by Wako Pure Chemical Industries, Ltd., polyvinyl butyral resin) was added as a binder resin and stirred for 30 minutes to obtain a coating solution.
The prepared coating solution was coated on a glass substrate with a bar coater (# 12) at room temperature, and heat-treated at a temperature of 50 ° C. for 30 minutes to obtain a heat ray shielding film.
As a result of measuring the spectral spectrum of the obtained heat ray shielding film, it was highly transparent in the visible light region and was able to shield heat rays having a wavelength of 1500 nm or more.

The tin oxide fine particles of the present invention, and the conductive film, laminate and resin composition comprising the same are effective for preventing charging of glass, plastic, etc. and preventing adhesion of dust. In addition, these are the antistatic effect, such as the display surface of the display device, its surface cover material, window glass, show window glass, instrument cover material, clean room floor and wall materials, and semiconductor packaging materials. And can be used for members that require an electromagnetic shielding effect. In addition, it can be applied to transparent electrodes such as touch panels, liquid crystals, and ELs. Furthermore, it can be applied to heat ray shielding coatings and heat ray shielding films for window glass and automobile glass.

Claims (10)

Tin oxide fine particles in which a second metal atom and a third metal atom are dissolved in tin oxide,
The second metal atom and the third metal atom are tungsten or zinc and are different from each other;
Tin oxide fine particles satisfying the following atomic ratio.
0.88 ≦ Sn / (Sn + W + Zn) ≦ 0.999
0.001 ≦ second metal atom / (Sn + W + Zn) ≦ 0.07
0 ≦ third metal atom / (Sn + W + Zn) ≦ 0.05
0.90 ≦ (Sn + W + Zn) / all metal atoms ≦ 1.00   2. The tin oxide fine particle according to claim 1, wherein all metal atoms contained in the tin oxide fine particle are substantially a tin atom, a second metal atom, and a third metal atom.   The tin oxide fine particles according to claim 1 or 2, having an average particle diameter of 1 to 500 nm. The tin oxide according to any one of claims 1 to 3, wherein colorimetric values in the L ^* a ^* b ^* color system are 20 <L ^* <60, 0 <a ^* <10, 0 <b ^* <20. Fine particles.   A tin oxide fine particle dispersion in which the tin oxide fine particles according to any one of claims 1 to 4 are dispersed in water, alcohol or an organic solvent.   A tin oxide fine particle-containing coating solution obtained by adding an inorganic binder or an organic binder to the tin oxide fine particle dispersion according to claim 5.   The resin composition which knead | mixed the tin oxide fine particle in any one of Claims 1-4 in the organic resin.   A resin composition obtained by kneading the tin oxide fine particle dispersion according to claim 5 in an organic resin.   The electrically conductive film obtained by apply | coating the tin oxide fine particle containing coating liquid of Claim 6.   A laminate comprising the conductive film according to claim 9.

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