JP6792834B2 - Method of manufacturing transparent conductive paint and method of forming transparent conductive film using this paint - Google Patents

Description

In the transparent conductive coating material according to the present invention, a high boiling point organic compound having a viscosity 10 times or more that of alcohol is mixed with an alcohol dispersion of a metal compound that precipitates metal by thermal decomposition at a ratio of 10% by weight or less. Manufacture paint. When this paint is applied or printed on the surface of the base material or parts to vaporize excess alcohol and then the metal compound is thermally decomposed, a collection of metal fine particles is deposited all at once on the surface of the base material or parts and is adjacent to the base material or parts. A transparent conductive film in which the metal fine particles are metal-bonded to each other and the laminated body in which the metal fine particles are stacked is coated with a small amount of an organic compound is formed on the surface of the base material or the component. Since this transparent conductive film is composed of a conductivity close to that of metal and a film thickness of about 1 μm, it can be used as a touch panel capable of detecting a touch operation with high sensitivity, a liquid crystal panel, or a transparent electrode of a solar cell. The transparent conductive coating material is also referred to as a transparent conductive paste, a transparent conductive coating agent, or a transparent conductive coating liquid.

In recent years, touch panels that have been used mainly for industrial equipment such as ticket vending machines at stations, ATMs at banks, and POS cash registers at convenience stores have become widely used in consumer equipment such as smartphones, car navigation systems, and digital cameras. .. There are four types of touch operation detection methods on the touch panel: resistance film method, surface type capacitance method, projection type capacitance method, optical method, and ultrasonic method. Resistance film method and projection type capacitance method The method is the current mainstream.
The resistance film method has a structure in which a film on which a transparent conductive film is formed is bonded to glass with a slight gap. When the film surface is pressed with a finger, the film comes into contact with the electrode film on the lower glass surface and a current flows, which causes a change in voltage, and this voltage change is detected to detect the touch position. Since it is pressure-sensitive, it can handle pen input, and because it has a simple structure, it has the feature of low manufacturing costs.
On the other hand, the capacitance method is a method in which a slight change in capacitance occurs when a finger touches the panel, and the touch position is detected from this change in capacitance. There are two types, a surface type and a projection type. .. In the surface capacitance method, a uniform electric field is generated from the electrodes at the four corners of the panel over the entire panel. When the panel is touched with a finger, the capacitance changes, and a weak current is generated in the electrodes at the four corners according to the distance to the touch position, and the touch position is detected from this weak current. The surface-type capacitance method is used for large panels, but it cannot support multi-touch, which detects multiple touch positions at the same time. The projected capacitance method overcomes this shortcoming and enables multi-touch, and has a structure in which two transparent conductive films in which the panels form electrode patterns in the X-axis direction and the Y-axis direction are superposed. Has. When a finger is touched on the panel, the capacitance of the conductive films arranged in a grid pattern changes at the same time, and the touch position is detected by measuring this. The projection type has a more complicated structure than the surface type, but it can detect the position with high accuracy, and it can also support multi-touch operations such as enlarging / reducing or rotating the photo on the screen with two fingers. , Adopted in mobile devices such as smartphones and tablet PCs, and became the mainstream of touch panels along with the resistive film method.
As described above, there are various types of touch panels, and a transparent conductive film is indispensable for each method. Most of the transparent conductive films that have already been put into practical use have a layer of ITO (Indium Tin Oxide, which is a transparent semiconductor material in the visible light region in which indium oxide is doped with tin) on the surface of a transparent substrate by sputtering. This is a film-forming technology.

Since a transparent conductive paint is applied or printed on the surface of a base material or a part to form a transparent conductive film, it is significantly cheaper than a transparent conductive film formed on a transparent base material by sputtering. A sex membrane can be formed. Further, it is used not only as a transparent conductive film in a touch panel, but also as an antistatic film or a surface stain prevention film by utilizing conductivity. Further, it is used as a transparent electrode of a liquid crystal panel if a conductivity close to that of a metal can be obtained, and as a transparent electrode of a solar cell if it has a conductivity close to that of a metal and a property of transmitting light from near ultraviolet rays to near infrared rays. ..
On the other hand, the higher the conductivity of the transparent conductive film and the thinner the film, the higher the sensitivity of detecting a touch operation on the touch panel. In particular, for small touch panels used in smartphones, car navigation systems, digital cameras, etc., high touch operation detection sensitivity is a commercial strength of such electronic devices. However, although ITO has the highest conductivity among transparent conductive materials, its resistivity is 57-75 times higher than that of a metal such as aluminum. Further, the conductivity of the film formed by the coating material in which the ITO fine particles are dispersed is two orders of magnitude or more lower than the conductivity of the film formed by heat-treating the ITO thin film formed by sputtering and advancing the crystallization. For this reason, various studies have been made to increase the conductivity of the transparent conductive film.
For example, Patent Document 1 describes a method for producing ITO fine powder having a large aspect ratio in which ITO fine powders easily come into contact with each other and easily overlap each other. That is, while maintaining the aqueous solution of indium salt and tin salt in a turbulent state having a Reynolds number of 15,000 or more, amino alcohol was added, and the precipitated precipitate was calcined at 300-800 ° C. Produce powder. However, in order to increase the conductivity of the film, it is necessary to form a path in which the ITO fine powders come into contact with each other and the charges move continuously, and the mixing ratio of the ITO fine powders must be increased. It doesn't become. However, the higher the mixing ratio of the ITO fine powder and the larger the aspect ratio of the ITO fine powder, the worse the dispersibility of the ITO fine particles in the coating material.
Further, Patent Document 2 describes a method for producing ITO fine particles having excellent dispersibility in a coating material and a method for producing a coating material in which the ITO fine particles are dispersed in a hydrophilic organic solvent. That is, 10-60 nm granular ITO fine particles produced by the arc plasma method and an acrylate compound having an ultraviolet curable property having two or more acryloyl groups or methacryloyl groups in the molecule are combined with alcohols and ethylene glycol mono. A paint is produced by dispersing it in alkyl ethers. However, in order to increase the conductivity of the film, the ITO fine particles must form a path in which the ITO fine particles come into contact with each other and the charges move continuously. However, due to the presence of the acrylate compound which is an insulator, the ITO fine particles come into contact with each other, and the ITO fine particles cannot form a path for electric charge to move. Further, in order to increase the conductivity, it is necessary to increase the mixing ratio of the ITO fine particles, but as the mixing ratio is increased, the amount of expensive ITO fine particles produced by the arc plasma method increases, and the acrylate compound is mixed. Since the ratio is low, there arises a problem that the smoothness of the film is poor.

Japanese Unexamined Patent Publication No. 2006-103984 Japanese Unexamined Patent Publication No. 2002-087544

The conventional transparent conductive paint is a paint in which transparent conductive fine particles are used as a filler and the fine particles are dispersed in a vehicle composed of a resin binder and a solvent. Therefore, there is an essential problem related to the material composition of the coating material, which is a problem caused by using the fine particles and a problem caused by dispersing the fine particles in the vehicle of the insulator.
That is, the first problem is that the binder, which is an insulator, prevents the fine particles from coming into contact with each other, and the presence of the binder increases the resistance value of the coating film.
The second problem is that as the fine particles become finer, the dispersibility of the fine particles in the vehicle deteriorates, and the resistance value of the coating film increases due to the uneven distribution of the fine particles. On the other hand, if the mixing ratio of the fine particles in the vehicle is reduced, the dispersibility of the fine particles in the coating film is increased, but the frequency of contact between the fine particles in the coating film is reduced, and the resistance value of the coating film is increased.
Further, the third problem is that the finer the fine particles, the easier it is for the fine particles to aggregate, which deteriorates the dispersibility of the fine particles in the vehicle, and as a result, the resistance value of the coating film increases. On the other hand, if the mixing ratio of the fine particles in the vehicle is reduced, the agglutination of the fine particles is less likely to occur, but the frequency of contact between the fine particles in the coating film is reduced and the resistance value of the film is increased.
Since the above-mentioned problems are essential problems related to the material composition of the paint, these problems can be solved only by the transparent conductive paint having a new material structure, which is completely different from the material structure of the conventional transparent conductive paint. Solvable. Therefore, there is a strong demand for the realization of a transparent conductive paint having a new material composition. The problem to be solved by the present invention is that a transparent conductive film having a conductivity close to that of metal and having a thickness of about 1 μm is formed on a base material or a component coated or printed with a transparent conductive paint. The purpose is to realize a conductive coating material and a transparent conductive film. Further, it is an object of the present invention to realize a transparent conductive film having high transparency and high transparency with respect to light in the near-ultraviolet region to the near-infrared region by using this transparent conductive coating material.

In the present invention, the method for producing a transparent conductive coating material that forms a transparent conductive film on the base material or the part by applying or printing on the base material or the part is to use alcohol as a metal compound that precipitates a metal by thermal decomposition. To prepare an alcohol dispersion in which the metal compound is dispersed in alcohol in a molecular state, and has a refractive index for light in the range from the near-ultraviolet region to the near-infrared region corresponding to a wavelength of 0.2-3 μm. However, the first property having a value between 1.4 and 1.5, the second property having a melting point lower than 20 ° C., the third property which dissolves or mixes with the alcohol, and the viscosity of the alcohol. An organic compound having a fourth property having a viscosity of 10 times or more that of the above and a fifth property having a boiling point higher than the thermal decomposition temperature of the metal compound is mixed with the alcohol dispersion at a ratio of 10% by weight or less. Then, the organic compound is dissolved or mixed with an alcohol to prepare a mixed solution in which the organic compound is uniformly mixed with the alcohol dispersion, whereby the mixed solution is applied or printed on a base material or a component. This is a method for producing a transparent conductive paint, wherein a transparent conductive paint composed of the mixed liquid in which a transparent conductive film is formed on the base material or the component is manufactured.

That is, according to this production method, when a metal compound that precipitates a metal by thermal decomposition is first dispersed in alcohol, the metal compound becomes a molecular state and is dispersed in alcohol in an amount of about 10% by weight. As a result, the metal raw material is liquid-phased. Next, when the organic compound is mixed with the alcohol dispersion at a ratio of 10% by weight or less, the organic compound dissolves or mixes with the alcohol. Therefore, the organic compound is a low-viscosity transparent conductive coating material that is uniformly mixed with the alcohol dispersion. Is manufactured.
The transparent conductive paint produced by such a method is further finely adjusted in viscosity according to the material, shape, and size of the base material or part, and is also brush-coated, roller-coated, spray-coated, dip-coated, and rolled. If a coating method consisting of a coater or the like, or a printing method consisting of bar coating, reverse coating, gravure printing, screen printing, etc. is selected, all the base materials or parts are coated with a coating film or a film thickness according to the viscosity. A printing film is formed. On the other hand, the low-viscosity paint applied or printed on the base material or part penetrates into the unevenness of the surface of the base material or part, and forms a coating film or a printed film on the surface of the base material or part.

The method of forming a transparent conductive film on the surface of a base material or a part using the transparent conductive paint manufactured by the above-mentioned manufacturing method is a method of forming a transparent conductive film on the surface of a base material or a part by using the transparent conductive paint manufactured by the above-mentioned manufacturing method on the surface of the base material or a part. The alcohol that constitutes the transparent conductive coating material is first vaporized, and the aggregate of fine crystals of the metal compound that constitutes the transparent conductive coating material is formed by applying or printing on the base material or the component. It is uniformly precipitated in the organic compound constituting the transparent conductive coating material, the fine crystals of the metal compound sink on the surface of the base material or the component, and the organic compound moves onto the fine crystals of the metal compound. After that, the fine crystals of the metal compound are thermally decomposed, a collection of metal fine particles is accumulated and precipitated on the surface of the base material or the component, and the adjacent metal fine particles are metal-bonded to each other, and the metal-bonded metal fine particles are metal-bonded. The laminated body is formed on the surface of the base material or the component, and the organic compound having a boiling point higher than the thermal decomposition temperature of the metal compound covers the surface of the laminated body, and the metal fine particles are stacked. A transparent conductive coating material produced by the above-mentioned production method, in which a transparent conductive film composed of a laminated body and a coating film of the organic compound covering the surface of the laminated body is formed on the surface of the base material or the component. Is a method of forming a transparent conductive film on the surface of a base material or a component using the above.

In other words, when a transparent conductive paint is applied or printed on a base material or part, the paint is a low-viscosity liquid, so the thickness of the coating film or printing film is thin, and the paint is applied to the unevenness of the surface of the base material or part. Get in. After that, when the heat treatment is performed, alcohol occupying most of the coating film or the printing film is vaporized first, and the coating film or the printing film having an extremely thin thickness is formed. At this time, since the metal compound is dispersed in the alcohol but not in the organic compound, a collection of fine crystals of the metal compound is uniformly precipitated in the organic compound. On the other hand, since the density of the fine crystals of the metal compound is higher than the density of the organic compound, the fine crystals of the metal compound sink to the surface of the base material or the component, and the organic compound moves on the collection of the fine crystals of the metal compound. Further, since the size of the fine crystals of the metal compound is one digit or more smaller than the unevenness of the surface of the base material or the component, the fine crystals enter the unevenness of the surface and cover the surface. The fine crystals of the metal compound correspond to the size of the metal fine particles precipitated by thermal decomposition. When the temperature is further raised, thermal decomposition of fine crystals of the metal compound occurs on the surface of the base material or the component. At this time, the metal compound is decomposed into a metal and an inorganic substance or an organic substance, and the inorganic substance or the organic substance takes away the heat of vaporization and vaporizes, and at the moment when the vaporization of the inorganic substance or the organic substance is completed, the granular substance having a size of 40-60 nm A collection of metal fine particles accumulates on the surface of the base material or parts and precipitates. Since the metal fine particles are precipitated in an active state without impurities, adjacent metal fine particles are metal-bonded to each other, and a laminate in which the metal-bonded metal fine particles are stacked is formed on the surface of the base material or the component. This laminate penetrates into the unevenness of the surface of the base material or the component and covers the surface of the base material or the component. Therefore, the laminate does not peel off from the surface of the base material or the component due to the anchor effect. On the other hand, an organic compound having a boiling point higher than the thermal decomposition temperature of the metal compound remains on the laminate, a small amount of the organic compound covers the laminate, and a film having a thickness of about 1 μm is formed on the surface of the base material or the component. It is formed.
This film is composed of a laminate in which metal-bonded metal fine particles are stacked and a film of an organic compound on the surface layer, and this film penetrates into the unevenness of the surface of the laminate of metal fine particles. The thickness of this film is as thin as about 1 μm, and when a person touches the film, it is elastically deformed by the thickness of the film of the organic compound, and the film is not peeled off. Moreover, even if a person touches the membrane, the existence of the membrane is unknown. Furthermore, since the vapor pressure of the organic compound at room temperature is extremely small, it does not evaporate for a long period of time. On the other hand, the laminate in which metal-bonded metal fine particles are stacked forms a path for continuous movement of electric charges, and an insulating organic compound is formed on the surface layer as an ultra-thin film, so that the conductivity of the film is high. Is close to the conductivity of metal. Further, since the laminate is shielded from the outside world by a film of an organic compound, the laminate does not change with time, and the conductivity of the film does not change for a long period of time.
This film has a high transmittance for incident light. That is, when light enters the film, surface reflection occurs on the surface of the film due to the difference in the refractive index between the film and air. Since the surface of the film is composed of a film of an organic compound, the incident light causes surface reflection according to the difference in the refractive index between the organic compound and air. This surface reflectance is the square of the value obtained by dividing the difference in the refractive index between the organic compound and air by the sum of the two. Further, the transmittance of the light entering the surface of the film is the square of the value obtained by subtracting the surface reflectance from 1 when the entire incident light is 1. Since the organic compound has a transmittance of 1.4-1.5 for light in the range from the near-ultraviolet region to the near-infrared region having a wavelength of 0.2-3 μm, it is in the near-ultraviolet region to the near-infrared region. With respect to the incident light, the surface reflectance is 3-4%, the transmittance is 92-94%, and the light extending from the near ultraviolet to the near infrared region is transmitted to the film with a transmittance not inferior to that of glass. The surface reflection and the total light transmittance will be described again in the following paragraph 10. Further, the light transmitted through the surface of the film is scattered by the laminated body in which the metal fine particles are stacked. Light scattering in the fine particles is based on the Rayleigh scattering formula when the size of the fine particles is sufficiently small with respect to the wavelength of the incident light. The Rayleigh scattering coefficient largely depends on the fourth power of the ratio of the size of the fine particles to the wavelength of the incident light, and also depends on the square of the size of the fine particles. Since the size of the metal fine particles of 40-60 nm is sufficiently smaller than the wavelength of the incident light of 0.2-3 μm, the scattering coefficient of the metal fine particles is extremely small, and the coating film exhibits high transparency. Rayleigh scattering will be described again in paragraph 11 below.
As described above, the film formed of the transparent conductive coating material has high transmittance and high transparency with respect to light in the region from the near-ultraviolet region to the near-infrared region. In addition, the conductivity of the film is close to that of metal, and the thickness is as thin as about 1 μm. Therefore, this film becomes a transparent conductive film. This solved the problem described in paragraph 5.
In addition, a functional film accompanied by firing may be formed on the transparent conductive film formed on the surface of the base material or the component. For example, a transparent conductive film formed on the surface of a glass substrate may be used as a transparent electrode of a dye-sensitized solar cell. That is, a paste made of fine powder of a metal oxide semiconductor is applied to the surface of the transparent conductive film and fired at a temperature of 400 ° C. or higher to form a porous metal oxide semiconductor film. When the paste is fired, the organic compounds forming the surface layer of the transparent conductive film are vaporized. Further, since the temperature of the laminated body in which the metal fine particles are stacked is higher than the temperature at which the metal fine particles are precipitated, the metal fine particles obtain thermal energy and take in the adjacent metal fine particles, and the metal fine particles grow. When the temperature is raised by 100 ° C. from the temperature at which the metal fine particles are precipitated, the metal fine particles grow and the volume of the metal fine particles increases by nearly 5%. Although the number of fine particles decreases as the metal fine particles grow, the grown metal fine particles are metal-bonded to each other to form a laminated body in which the grown metal fine particles are stacked. Even if the metal fine particles grow, the size of the metal fine particles is sufficiently smaller than the wavelengths from the near ultraviolet rays to the near infrared rays, so that no light is scattered. In this way, the glass substrate on which the transparent conductive film is formed can be used as a transparent electrode of a dye-sensitized solar cell without impairing the function of the transparent conductive film even by firing.
On the other hand, the method for producing a transparent conductive coating material and the method for forming a transparent conductive film in the present invention bring about various excellent effects.
First, the production of a transparent conductive coating material consists of only two extremely simple steps of dispersing the organometallic compound in alcohol and mixing the organic compound in the alcohol dispersion. When the two steps are carried out in succession, the transparent conductive paint can be mass-produced at low cost.
Secondly, the treatment for forming the transparent conductive film is only heat treatment, vaporizing the alcohol, and then thermally decomposing the metal compound, so that the transparent conductive film can be produced at low cost.
Third, the raw materials for the transparent conductive paint are metal compounds, alcohols and organic compounds, all of which are general-purpose industrial chemicals. Moreover, since expensive transparent conductive fine particles are not used, a transparent conductive film that is significantly cheaper than the conventional one can be manufactured.
Fourth, even if the surface of the base material or parts is contaminated with particulate pollutants such as dust and dirt, or oil-based pollutants consisting of organic substances, they are vaporized when the metal compounds are thermally decomposed. Will be removed. Further, even if the pollutant cannot be removed by the thermal decomposition of the metal compound, the conductivity of the laminate does not change because the laminate composed of a collection of metal fine particles is formed by covering the remaining contaminant. Further, since the laminate is coated with a film of an organic compound, new pollutants and substances that promote chemical changes do not adhere to the laminate, and the conductivity of the laminate does not change with time. Therefore, it is not necessary to clean the surface of the base material and parts in advance.
Fifth, the viscosity of the transparent conductive paint produced is low. Therefore, the viscosity of the paint is finely adjusted according to the material, shape, and size of the base material or parts, and further, a coating method such as brush coating, roller coating, spray coating, dip coating, roll coater, etc. is used. By selecting a printing method such as bar coating, reverse coating, gravure printing, screen printing, etc., all substrates or parts have high transparency and high transparency for light from the near-ultraviolet region to the near-infrared region. In addition, a transparent conductive film having a conductivity close to that of metal and having a film thickness of about 1 μm can be formed. This makes it possible to manufacture a touch panel that detects touch with high sensitivity, a liquid crystal panel, a transparent electrode of a solar cell, and the like, regardless of the material, shape, and size of the base material or component.

Here, the surface reflectance and the total light transmittance will be described. When light enters the transparent conductive film, surface reflection occurs according to the difference in refractive index between the air and the film surface. Therefore, the glass also has a loss due to surface reflection, and the most common 2 mm float glass has a total light transmittance of about 90% in the wavelength region of visible light.
The surface reflectance R on the surface of light incident perpendicularly to the film is calculated by Equation 1 consisting of the refractive index n of the film surface and the refractive index m of air. Further, the total light transmittance T is calculated by the mathematical formula 2 including the surface reflectance R. Since the surface of the film is composed of an organic compound, surface reflection occurs according to the difference between the refractive index of the organic compound and the refractive index of air. Since the refractive index of the organic compound with respect to wavelengths ranging from the near-ultraviolet region to the near-infrared region is 1.4-1.5, the surface reflectance R is 3-4% and the total light transmittance T is 92-94. With a transmittance that is not inferior to that of float glass, light extending from the near-ultraviolet region to the near-infrared region is transmitted through the surface of the film.
Number 1
R = (n−m) ² / (n + m) ²
Number 2
T = (1-R) ²

Next, light scattering will be described. The light incident on the organic compound is scattered by a collection of metal fine particles. Since the metal fine particles having a size of 40-60 nm are sufficiently small for a wavelength of 0.2-3 μm extending from the near-ultraviolet region to the near-infrared region, the Rayleigh scattering formula shown in Equation 3 can be applied to light scattering. .. In Equation 3, S is the scattering coefficient, λ is the wavelength of the incident light, D is the particle size, and m is the ratio of the refractive index of the metal fine particles to the refractive index of the organic compound. Also, π is the pi. The scattering coefficient S in Equation 3 largely depends on the ratio D / λ of the particle diameter D to the wavelength λ of the incident light, and also depends on the square of the particle diameter D. Since the particle diameter D is close to 1/10 of the wavelength λ of the incident light, the scattering coefficient S is extremely small with respect to the metal fine particles. As a result, the transparent conductive film exhibits high transparency with respect to incident light extending from the near-ultraviolet region to the near-infrared region.
Number 3
^{S = 4/3 · π 5} / λ 4 · D 6 {(m 2 -1) / (m 2 +1)} 2

The above-mentioned method for producing a transparent conductive coating material uses, as the above-mentioned metal compound, an inorganic metal compound having a metal complex ion in which a ligand composed of an inorganic molecule or an inorganic ion is coordinated and bonded to the metal ion. Using methanol as the alcohol and any organic compound consisting of carboxylic acid esters, glycols or glycol ethers as the organic compound, a transparent conductive paint is produced according to the method for producing a transparent conductive paint described above. This is the method for producing the above-mentioned transparent conductive coating material.

That is, the inorganic metal compound having an intermetallic ion is thermally decomposed in a reducing atmosphere at 180-220 ° C. to precipitate a metal. Further, it is dispersed in methanol up to about 10% by weight. Therefore, the inorganic metal compound becomes a raw material for precipitating a metal by thermal decomposition. Therefore, a transparent conductive film can be formed on a base material or a component having a heat resistance of 220 ° C. or higher in a reducing atmosphere.
That is, since the ligand composed of an inorganic molecule or an inorganic ion has a low molecular weight, when an inorganic metal compound having a metal complex ion in which the ligand is coordinated to a metal ion is heat-treated in a reducing atmosphere, the ligand is coordinated. The bond is split at temperatures below 180-220 ° C and decomposed into inorganics and metals. When the temperature is further raised, the inorganic substances take away the heat of vaporization and vaporize, and after the vaporization of all the inorganic substances is completed, the metal precipitates at 180-220 ° C. That is, among the ions constituting the inorganic metal compound, the metal ion located in the center of the molecule is the largest. Therefore, the distance between the metal ion and the ligand is the longest. Therefore, when the inorganic metal compound is heat-treated in a reducing atmosphere, the coordination bond portion in which the metal ion binds to the ligand is first separated. As such inorganic metal compounds, an ammine complex in which ammonia NH ₃ serves as a ligand and coordinates to a metal ion, an aqua complex in which water H ₂ O serves as a ligand and coordinates to a metal ion, and chlorine. A chloro complex in which ion Cl ⁻ or chlorine ion Cl ⁻ and ammonia NH ₃ serve as a ligand to coordinate bond to a metal ion, and cyano group CN ⁻ serves as a ligand ion to coordinate bond to a metal ion. Examples thereof include a complex, a bromo complex in which a bromine ion Br ⁻ becomes a ligand ion and coordinates a bond with a metal ion, and an iodo complex in which an iodine ion I ⁻ becomes a ligand ion and coordinates a bond with a metal ion.
Next, among the carboxylic acid esters, glycols or glycol ethers, first, the refractive index for a wavelength of 0.2-3 μm extending from the near ultraviolet ray region to the near infrared region is 1.4-1.5. It has a value, secondly, it has a melting point lower than 20 ° C., thirdly it dissolves or mixes with methanol, fourthly it has a viscosity 10 times or more the viscosity of methanol, and fifthly it is the temperature at which the inorganic metal compound thermally decomposes. There are organic compounds having these five properties, which have a higher boiling point. All of these organic compounds are general-purpose industrial chemicals.
Therefore, when such an organic compound is mixed with a methanol dispersion of an inorganic metal compound, the organic compound dissolves or mixes with methanol, so that the organic compound is uniformly mixed with the methanol dispersion of the inorganic metal compound. When this mixed solution is applied or printed on the base material or parts, and the temperature is further raised to thermally decompose the inorganic metal compound, a collection of granular metal fine particles having a size of 40-60 nm is formed on the surface of the base material or parts. It piles up and precipitates. As a result, a laminated body in which metal fine particles are stacked is formed. At this time, the organic compound having a boiling point higher than the thermal decomposition temperature remains, and a transparent conductive film in which the laminate of metal fine particles is coated with a small amount of the organic compound is formed. Therefore, the organic compound becomes a raw material for the transparent conductive coating material.

In the method for producing a transparent conductive coating material, a metal octylate compound is used as the metal compound, methanol is used as the alcohol, and an organic compound belonging to carboxylic acid esters is used as the organic compound. This is the above-mentioned method for producing a transparent conductive paint, which comprises producing a transparent conductive paint according to a manufacturing method for producing a transparent conductive paint.

That is, the metal octylate compound is thermally decomposed at 290 ° C. to precipitate a metal. Further, it is dispersed in methanol up to about 10% by weight. Therefore, the metal octylate compound becomes a raw material for precipitating a metal by thermal decomposition. When the base material or part made of synthetic resin is covered with a transparent conductive film by thermal decomposition of the metal octylate compound, the base material or part is covered with a collection of fine crystals of the metal octylate compound and an organic compound. The temperature is raised to 290 ° C. in this state. At this time, since the temperature of the base material or the component is raised to 290 ° C. in a state of being shielded from the atmosphere, thermal decomposition of the synthetic resin does not occur. Therefore, the surface of the base material or the component made of the synthetic resin can be covered with the transparent conductive film without irreversibly changing the properties of the synthetic resin.
That is, among the ions constituting the metal octylate compound, the metal ion is the largest. Therefore, in the octylate metal compound in which the oxygen ion constituting the carboxyl group of octyl acid is covalently bonded to the metal ion, the distance between the oxygen ion constituting the carboxyl group and the metal ion is longer than the distance between other ions. When a metal compound having such a molecular structure is heat-treated, when the boiling point of the octyl acid is exceeded, the bond portion between the oxygen ion and the metal ion constituting the carboxyl group is first separated to separate the octyl acid and the metal. Further, the octyl acid takes away the heat of vaporization and vaporizes, and when the vaporization is completed, the metal is precipitated. As such an organometallic compound, in addition to the octylate metal compound, there are carboxylic acid metal compounds such as laurate metal compound and stearate metal compound. On the other hand, at atmospheric pressure, the boiling point of octyl acid is 228 ° C, the boiling point of lauric acid is 296 ° C, and the boiling point of stearic acid is 361 ° C. Therefore, since the thermal decomposition temperature of the metal octylate compound composed of octyl acid having the lowest boiling point is the lowest, the heat treatment cost of the transparent conductive coating material can be reduced by using the metal octylate compound.
In addition, metal octylate compounds are inexpensive industrial chemicals that can be easily synthesized. That is, when octyl acid is reacted with a strong alkali, an alkali metal octylate compound is produced. After that, when the alkali metal octylate compound is reacted with the inorganic metal compound, a metal octylate compound composed of various metals is synthesized. Therefore, it is the cheapest organometallic compound among the organometallic compounds.
Next, the organic compounds belonging to the carboxylic acid esters have a viscosity of 1.4-1.5 with respect to a wavelength of 0.2-3 μm, which first extends from the near-ultraviolet region to the near-infrared region. Secondly, the melting point is lower than 20 ° C., thirdly, it is dissolved or mixed with methanol, fourthly, it has a viscosity 10 times or more the viscosity of methanol, and fifthly, it has a boiling point higher than 290 ° C., these five properties. There is an organic compound that also combines. Such organic compounds are general-purpose industrial chemicals.
When such an organic compound is mixed with a methanol dispersion of a metal octylate, the organic compound dissolves or mixes with methanol, so that the organic compound is uniformly mixed with the methanol dispersion of the metal octylate. When this mixed solution is applied or printed on the base material or parts, and the temperature is further raised to thermally decompose the metal octylate compound, a collection of granular metal fine particles having a size of 40-60 nm is formed on the base material or parts. It accumulates on the surface and precipitates. As a result, a laminate composed of a collection of metal fine particles is formed. On the other hand, the organic compound having a boiling point higher than 290 ° C. remains, and a transparent conductive film in which the laminate of metal fine particles is coated with a small amount of the organic compound is formed. Therefore, the organic compound becomes a raw material for the transparent conductive coating material.

It is a figure which shows typically the cross section of the transparent conductive film which coated on the surface of the transparent film of acrylic resin with the film | coating | film which made | It is a figure which shows typically the cross section of the transparent conductive film which was coated on the surface of the transparent film of a polyester resin with the laminate |

Embodiment 1
As an embodiment of a metal compound that precipitates a metal by heat treatment, an inorganic metal compound having a metal complex ion in which a ligand composed of an inorganic molecule or an inorganic ion is coordinated to the metal ion is relatively thermally decomposed. Explain that is suitable as a low metal compound. Here, among the metal elements, a copper compound that precipitates copper, which has the second highest conductivity and thermal conductivity next to silver, by thermal decomposition will be described.
In order for a copper compound to be a raw material for a transparent conductive coating material, it is necessary to have both the property of dispersing in alcohol and the property of precipitating copper by thermal decomposition. Inorganic copper compounds such as low molecular weight copper chloride, copper sulfate, and copper nitrate are dissolved in alcohol and copper ions are eluted in the alcohol, so that fine crystals of the inorganic copper compound do not precipitate after the alcohol is vaporized. Further, low molecular weight inorganic copper compounds such as copper oxide, copper chloride and copper sulfide are not dispersed in alcohols. Therefore, these low molecular weight inorganic copper compounds are not dispersed in alcohol.
Of all the chemical reactions that produce copper from copper compounds, the pyrolysis reaction is the simplest chemical reaction. That is, copper is precipitated only by raising the temperature of the copper compound. Further, if the thermal decomposition temperature of the copper compound is low, a transparent conductive film can be formed on a base material or a component having low heat resistance. A copper complex having a copper complex ion coordinated to a copper ion located in the center of the molecular structure in which a molecule composed of an inorganic substance or an ion composed of the inorganic substance serves as a ligand has a small molecular weight of the ligand composed of the inorganic substance. Therefore, the temperature at which the organic copper compound having a larger molecular weight forms a ligand is lower than the temperature at which the organic copper compound thermally decomposes in the atmospheric atmosphere. Such a copper complex is a substance that is relatively more expensive than an organic copper compound, but a transparent conductive film can be formed on a base material or a component having low heat resistance.
That is, the copper ion is the largest among the molecules constituting the copper complex. Incidentally, the covalent radius of the copper atom is 132 ± 4 pm, while the covalent radius of the nitrogen atom is 71 ± 1 pm, and the covalent radius of the oxygen atom is 66 ± 2 pm. Therefore, in the molecular structure of the copper complex, the distance of the coordination bond portion where the ligand is coordinated to the copper ion is the longest. Therefore, in the heat treatment of the reducing atmosphere, the coordination bond portion is first divided and decomposed into copper and an inorganic substance, and copper is precipitated after the vaporization of the inorganic substance is completed.
Among such copper complexes, an ammine complex, chlorine ion Cl ⁻ , in which ammonia NH ₃ serves as a ligand and coordinates with copper ions, or chlorine ion Cl ⁻ and ammonia NH ₃ are ligands. Since the chloro complex that is coordinated to the copper ion is easier to synthesize than other copper complexes, it can be produced at a low production cost. Further, when such a copper complex is heat-treated in a reducing atmosphere such as ammonia gas or hydrogen gas, the coordination bond site is first divided, and the thermal decomposition is completed at a relatively low temperature of about 200 ° C. Further, it is dispersed in methanol to a dispersion concentration close to 10% by weight. Examples of such a copper complex ion include tetraammine copper complex ion [Cu (NH ₃ ) ₄ ] ²⁺ , or hexaammine copper complex ion [Cu (NH ₃ ) ₆ ] ²⁺ , and as a copper complex, for example, tetraammine copper. There are nitrates [Cu (NH ₃ ) ₄ ] (NO ₃ ) ₂ or hexaammine copper sulfate [Cu (NH ₃ ) ₆ ] SO ₄ .
As described above, as a material for precipitating copper by thermally decomposing a copper compound at a relatively low temperature, a copper complex in which a ligand composed of an inorganic molecule or an inorganic ion is coordinated to the copper ion. Copper complexes with ions are suitable. As a result, a transparent conductive film can be formed on the surface of the base material or component having low heat resistance.

Embodiment 2
Explain that a metal octylate compound is suitable as another embodiment of a metal compound that precipitates a metal by heat treatment. The metal compound used as a raw material for the transparent conductive coating material has two properties of first dispersing in methanol and precipitating the metal by the second thermal decomposition. Here, it will be described that the metal is aluminum and aluminum octylate is suitable as a substance having two properties. Aluminum has a small density of 2.70 g / cm ^3, and has the second highest conductivity and thermal conductivity after silver, copper, and gold. Therefore, by using aluminum octylate as a raw material, a transparent conductive film that is lightweight and has excellent conductivity and thermal conductivity can be formed.
First, an aluminum compound dispersed in alcohol will be described. Aluminum chloride dissolves in water and hydrolyzes to aluminum hydroxide and hydrochloric acid. Also, aluminum hydroxide does not disperse in alcohol. Furthermore, aluminum sulfate dissolves in alcohol and aluminum ions elute. Also, aluminum oxide does not disperse in alcohol. Therefore, these low molecular weight inorganic aluminum compounds are not dispersed in alcohol.
An aluminum complex having an aluminum complex ion coordinate-bonded to an aluminum ion located in the center of the molecular structure, in which a molecule or ion made of an inorganic substance serves as a ligand, precipitates aluminum oxide by thermal decomposition. It does not become a raw material that precipitates aluminum by decomposition. Such aluminum complexes, and aqua complex having water molecules between H _{2 O} ligand, hydroxide ions OH ^- and the like hydroxo complex having as a ligand.
Next, the organoaluminum compound precipitates aluminum by thermal decomposition. Among the chemical reactions in which aluminum is produced from organoaluminum compounds, the chemical reaction by the simplest treatment is the thermal decomposition reaction. That is, aluminum is precipitated only by raising the temperature of the organoaluminum compound. Further, if the organoaluminum compound can be easily synthesized, it can be produced at low cost. An organoaluminum compound having these properties is an aluminum carboxylate compound.
Among the ions constituting the aluminum carboxylate compound, the aluminum ion Al ³⁺ located in the center of the molecule is the largest. Therefore, when the aluminum ion Al ³⁺ and the oxygen ion O ⁻ constituting the carboxyl group are covalently bonded, the distance between the aluminum ion Al ³⁺ and the oxygen ion O ⁻ is maximized. The reason for this is that the covalent radius of the aluminum ion atom is 121 ± 4 pm, the covalent radius of the oxygen ion atom is 66 ± 2 pm, and the covalent radius of the carbon atom is 73 pm. Therefore, in the aluminum carboxylate compound in which the aluminum ion and the oxygen ion constituting the carboxyl group are covalently bonded, the bonding portion between the aluminum ion having the longest bonding distance and the oxygen ion constituting the carboxyl group at the boiling point of the carboxylic acid is formed. It is first split and separated into aluminum and carboxylic acid. When the temperature is further raised, if the carboxylic acid is a saturated fatty acid, the carboxylic acid takes away the heat of vaporization and vaporizes, and aluminum precipitates after the vaporization of the carboxylic acid is completed. Examples of such an aluminum carboxylate compound include aluminum octylate, aluminum laurate, and aluminum stearate. Most of such aluminum carboxylate compounds are inexpensive industrial chemicals commercially available as metal soaps.
Moreover, the aluminum carboxylate compound is easy to synthesize. That is, when a carboxylic acid is reacted in a strong alkaline solution such as sodium hydroxide, an alkali metal carboxylate compound is produced. When this alkali metal carboxylate compound is reacted with an inorganic aluminum compound such as aluminum sulfate, an aluminum carboxylate compound is produced.
Further, in the aluminum carboxylate compound composed of saturated fatty acid, if the boiling point of the saturated fatty acid is low, the aluminum carboxylate compound is thermally decomposed at a low temperature, and the heat treatment cost for precipitating aluminum can be reduced. When the hydrocarbons constituting the saturated fatty acid have a long chain structure, the longer the long chain, that is, the larger the molecular weight of the saturated fatty acid, the higher the boiling point of the saturated fatty acid. By the way, the boiling point of lauric acid having a molecular weight of 200.3 at atmospheric pressure is 296 ° C., and the boiling point of stearic acid having a molecular weight of 284.5 at atmospheric pressure is 361 ° C. Therefore, an aluminum carboxylate compound composed of a saturated fatty acid having a relatively small molecular weight is desirable as a raw material for precipitating aluminum because the thermal decomposition temperature is relatively low.
Further, when the saturated fatty acid is a saturated fatty acid having a branched chain structure, the chain length is shorter than that of the saturated fatty acid having a linear structure, and the boiling point is further lowered. As a result, the aluminum carboxylate compound composed of saturated fatty acids having a branched chain structure is thermally decomposed at a low temperature. Furthermore, since saturated fatty acids having a branched chain structure have polarity, aluminum carboxylate compounds composed of saturated fatty acids having a branched chain structure also have polarity and are dispersed in a relatively high proportion in polar organic solvents such as alcohol. .. Octylic acid is a saturated fatty acid having such a branched structure. That is, the structural formula of octyl acid is represented by CH ₃ (CH ₂ ) ₃ CH (C ₂ H ₅ ) COOH, and CH is branched into an alkane of CH ₃ (CH ₂ ) ₃ and C ₂ H ₅ to CH. The carboxyl group COOH is bonded. The boiling point of octyl acid at atmospheric pressure is 228 ° C, which is 68 ° C lower than the boiling point of lauric acid described above. Therefore, aluminum octylate having a low thermal decomposition temperature is desirable as a raw material for precipitating aluminum. Aluminum octylate is thermally decomposed at 290 ° C. in the air atmosphere to precipitate aluminum, which is dispersed in methanol up to 10% by weight.
If the carboxylic acid is an unsaturated fatty acid, the carbon atom becomes excessive with respect to the hydrogen atom. Therefore, when the aluminum carboxylate compound composed of the unsaturated fatty acid is thermally decomposed, an oxide of aluminum is precipitated. Further, in the aluminum carboxylate compound in which the oxygen ion constituting the carboxyl group serves as a ligand and approaches the aluminum ion to coordinate bond, the distance between the aluminum ion and the oxygen ion is shortened, and conversely, the oxygen ion is aluminum. The distance between the ion and the ion bound on the opposite side is the longest. In such a thermal decomposition reaction of the aluminum carboxylate compound, the bond portion of the oxygen ion with the ion bonded to the aluminum ion on the opposite side is first separated, and as a result, aluminum oxide is precipitated.
Here, copper octylate is used as the metal compound octylate, and the thermal decomposition reaction in both the air atmosphere and the nitrogen atmosphere will be described from the TG-DTA characteristics in which the temperature is raised at a temperature rising rate of 5 ° C./min. The TG characteristic is the result of continuously measuring the weight change of copper octylate with the temperature rise, and the DTA characteristic is the temperature difference from the reference substance due to the thermal change generated in the copper octylate with the temperature rise. It is the result of the differential thermal analysis detected as. In both the air atmosphere and the nitrogen atmosphere, after the gradual weight loss due to the withdrawal of water is completed, when the boiling point of octyl acid exceeds 228 ° C., a clear weight loss appears, and the weight drops sharply as the temperature rises. Then the thermal decomposition proceeds. That is, in the air atmosphere, the calorific value rapidly increased at 278.8 ° C., the calorific value peak appeared at 280.7 ° C., the exothermic phenomenon ended at 285.4 ° C., and the weight decreased by 78.5%. On the other hand, in a nitrogen atmosphere, the calorific value increased sharply at 285.3 ° C., the calorific value peaked at 289.0 ° C., the exothermic phenomenon ended at 291.3 ° C., and the weight decreased by 77.4%. Therefore, in the thermal decomposition of copper octylate, it can be considered that the thermal decomposition starts at the boiling point of the octyl acid and ends at 290 ° C. in both the air atmosphere and the nitrogen atmosphere to precipitate copper. Further, since the theoretical weight loss of copper octylate in which copper is precipitated by thermal decomposition of copper octylate is 81.8% by weight, it can be considered that copper is precipitated by thermal decomposition.

Embodiment 3
In this embodiment, firstly, the refractive index for light having a wavelength of 0.2-3 μm in the range from the near-infrared region to the near-infrared region has a value of 1.4-1.5, and secondly, the melting point is It is lower than 20 ° C., thirdly it dissolves or mixes with methanol, fourthly it has a viscosity 10 times or more that of methanol, and fifthly it is the temperature at which a metal complex composed of an inorganic metal compound thermally decomposes, or octylic acid. This is an embodiment relating to an organic compound having these five properties, which has a boiling point higher than the temperature at which the metal compound is thermally decomposed. Organic compounds having these five properties include organic compounds belonging to carboxylic acid esters, glycols, or glycol ethers. The viscosity of methanol is 0.59 mPa sec at 20 ° C. The refractive index described below is a representative value of the refractive index of sodium at 20 ° C. with respect to the D line (wavelength is 589.3 nm), and all the organic compounds are 0.2 in the near-ultraviolet region to the near-infrared region. The index of refraction for a wavelength of -3 μm is between 1.4 and 1.5, with only a slight change in the fourth digit of the effective number.

First, carboxylic acid esters will be described. Carboxylate esters are divided into first esters composed of saturated carboxylic acids, second esters composed of unsaturated carboxylic acids, and third esters composed of aromatic carboxylic acids.
Among the esters consisting of the first saturated carboxylic acid, the carboxylic acid ester dissolved in methanol, having a melting point lower than 20 ° C. and a boiling point of 200-290 ° C. is higher than butyl caproate having a boiling point of 207 ° C. or higher. It is a carboxylic acid ester having the molecular weight of. However, the viscosity of these carboxylic acid esters is less than 10 times that of methanol.
Among the esters composed of saturated carboxylic acids, the carboxylic acid ester which is dissolved in methanol and has a property of having a melting point lower than 20 ° C. and a boiling point higher than 290 ° C. is higher than that of ethyl myristate having a boiling point of 295 ° C. Carboxylates with molecular weight. By the way, ethyl myristate has a viscosity at 20 ° C. of 6 mPa seconds and a refractive index of 1.436. Therefore, esters composed of a metal octylate compound, methanol, and a saturated carboxylic acid having a molecular weight equal to or higher than that of ethyl myristate are raw materials for transparent conductive coating materials.
Next, among the esters consisting of the second unsaturated carboxylic acid, the carboxylic acid ester dissolved in methanol and having a melting point lower than 20 ° C. and a boiling point higher than 290 ° C. has a molecular weight equal to or higher than that of methyl oleate. It is a carboxylic acid ester with. By the way, the boiling point of phenyl methacrylate is 249 ° C, and the boiling point of methyl oleate is 351 ° C. The viscosity of methyl oleate is 51 mPa seconds at 20 ° C., and the refractive index is 1.452. Therefore, esters composed of metal octylate compounds, methanol, and unsaturated carboxylic acids having a molecular weight equal to or higher than methyl oleate are raw materials for transparent conductive coating materials.
Furthermore, among the esters consisting of the third aromatic carboxylic acid, the carboxylic acid ester dissolved in methanol, having a melting point lower than 20 ° C. and a boiling point between 200-290 ° C. has a higher molecular weight than ethyl benzoate. It is a large carboxylic acid ester. Incidentally, the boiling point of ethyl benzoate is 212 ° C, and the boiling point of propyl benzoate is 230 ° C. However, the viscosity of these benzoic acid esters is less than 10 times that of methanol.
Among the esters composed of aromatic carboxylic acids, the carboxylic acid ester which is dissolved or mixed with methanol and has a property of having a melting point lower than 20 ° C. and a boiling point higher than 290 ° C. has a molecular weight of diethyl phthalate or higher. It is a carboxylic acid ester. By the way, the boiling point of diethyl phthalate is 295 ° C, and the boiling point of dibutyl phthalate is 340 ° C. The viscosity of diethyl phthalate is 13 mPa seconds at 20 ° C., and the refractive index is 1.50. The viscosity of dibutyl phthalate is 9.72 mPa seconds at 37.8 ° C., and the refractive index is 1.490-1.495. Further, the viscosity of dioctyl phthalate having a boiling point of 385 ° C. is 81.4 mPa seconds at 20 ° C. and 1.485 at a refractive index of 25 ° C. Therefore, esters composed of a metal octylate compound, methanol, and an aromatic carboxylic acid having a molecular weight equal to or higher than diethyl phthalate can be used as raw materials for transparent conductive coating materials.

Next, glycols will be described. There are six types of glycols: ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, and tripropylene glycol. All of these glycols are liquid monomers that are dissolved or miscible in methanol and have a melting point lower than 20 ° C.
Diethylene glycol has a boiling point of 244 ° C., a viscosity of 20 ° C. of 36 mPa seconds, and a refractive index of 1.447. Propylene glycol has a boiling point of 188 ° C., a viscosity of 25 ° C. of 48.6 mPa seconds, and a refractive index of 1.429-1.434. Further, dipropylene glycol has a boiling point of 232 ° C., a viscosity of 25 ° C. of 75 mPa seconds, and a refractive index of 1.440-1.442. Further, tripropylene glycol has a boiling point of 265 ° C., a viscosity of 25 ° C. of 57.2 mPa seconds, and a refractive index of 1.442. Therefore, the inorganic metal compound having an intermetallic ion, methanol, and the above-mentioned glycols are raw materials for a transparent conductive coating material.

Finally, glycol ether will be described. There are three types of glycol ethers: ethylene glycol ethers, propylene glycol ethers, and dialkyl glycol ethers in which hydrogen at the end of each of ethylene glycol, diethylene glycol, and triethylene glycol is substituted with an alkyl group. These glycol ethers are liquids that dissolve in methanol and have a melting point below 20 ° C.
First, ethylene glycol-based ethers having a boiling point between 200-290 ° C. have a boiling point of 229 ° C., a viscosity at 20 ° C. of 7.6 mPa seconds, and a refractive index of 1.4316, which is 2 ethylhexyl glycol. At 231 ° C, the viscosity at 20 ° C is 6.5 mPa seconds and the refractive index is 1.436, and the boiling point is 245 ° C and the viscosity at 20 ° C is 30.5 mPa seconds and the refractive index is 1.539. Phenylglycol, a methyltriglycol having a boiling point of 249 ° C. and a viscosity of 20 ° C. of 7.5 mPa seconds and a refractive index of 1.427, and a methyltriglycol having a boiling point of 256 ° C. and a viscosity of 20 ° C. of 12 mPa seconds. Benzyl glycol with a rate of 1.523, hexyldiglycol with a boiling index of 259 ° C and a viscosity of 20 ° C for 8.6 mPa seconds and a refractive index of 1.437, and a boiling point of 271 ° C and a viscosity of 20 ° C. There are butyltriglycol having a refractive index of 1.438 at 8.1 mPa sec and diethylhexyl glycol having a boiling point of 272 ° C and a viscosity of 20 ° C. of 10.4 mPa sec and a refractive index of 1.442. Therefore, the inorganic metal compound having an intermetallic ion, methanol, and the above-mentioned glycol ethers are raw materials for a transparent conductive coating material.
Further, ethylene glycol-based ether having a boiling point higher than 290 ° C. includes benzyl diglycol having a boiling point of 302 ° C., a viscosity of 20 ° C. of 19.3 mPa seconds, and a refractive index of 1.5118. Therefore, the metal octylate compound, methanol, and benzyl diglycol are raw materials for the transparent conductive coating material.
Next, the propylene glycol-based ether having a boiling point between 200 and 290 ° C. has a boiling point of 231 ° C., a viscosity of 20 ° C. of 7.4 mPa sec, and a boiling point of 1.426 butylpropylene diglycol. At 243 ° C, the viscosity at 20 ° C is 23.2 mPa seconds and the refractive index is 1.524, and the boiling point is 274 ° C and the viscosity at 20 ° C is 8.2 mPa seconds and the refractive index is 1. There is .428 butylpropylene triglycol. Therefore, the inorganic metal compound having an intermetallic ion, methanol, and the above-mentioned glycol ethers are raw materials for a transparent conductive coating material.

Embodiment 4
Here, whether or not a transparent conductive film can be formed on a synthetic resin base material or component having relatively low heat resistance will be described from the thermal decomposition reaction of the synthetic resin. That is, when the thermal decomposition of the synthetic resin starts, the molecular structure of the polymer changes irreversibly, and the properties of the synthetic resin cannot be restored. Therefore, if the thermal decomposition of the synthetic resin does not start by the thermal decomposition of the metal octylate compound, a transparent conductive film can be formed on the base material or the component of the synthetic resin.
By the way, the thermal decomposition reaction of the polymer constituting the synthetic resin is significantly different between the atmosphere in which oxygen gas is present and the atmosphere in which nitrogen gas is present. That is, the thermal decomposition of the polymer in the atmosphere where oxygen gas is present is accompanied by heat generation because it is the thermal decomposition due to the oxidation reaction. This exothermic phenomenon promotes the thermal decomposition of macromolecules composed of organic substances that are easily oxidized. On the other hand, in the thermal decomposition in a nitrogen atmosphere, the oxidation reaction does not occur, the thermal decomposition due to the endothermic reaction occurs, and the exothermic phenomenon does not occur. Therefore, the temperature at which the polymer starts thermal decomposition shifts to the high temperature side with a significant delay compared to the atmosphere in which the oxygen gas is present. For example, the thermal decomposition of the high-density polyethylene resin starts at around 250 ° C. in an air atmosphere, whereas it starts at around 400 ° C. in a nitrogen atmosphere, and shifts to a high temperature side by 150 ° C.
Pyrolysis of other polymers in a nitrogen atmosphere begins at 280 ° C. for the polyacetal resin POM and ends at 420 ° C. Polystyrene resin PS begins thermal decomposition at 350 ° C. and ends at around 460 ° C. Pyrolysis of polyethylene terephthalate resin PET starts at 425 ° C and ends at around 480 ° C. The polypropylene resin PP begins thermal decomposition at 370 ° C and ends at around 500 ° C. The high-density polyethylene resin HDPE begins thermal decomposition at 400 ° C and ends at around 520 ° C. The polytetrafluorethylene resin PTFE starts thermal decomposition at 490 ° C and ends at around 640 ° C.
Further, in a helium gas atmosphere, in the polyvinyl chloride resin PVC, separation of nonflammable and harmful hydrogen chloride gas and flammable gas benzene and naphthalene starts from around 220 ° C with an endothermic reaction and rapidly occurs around 260 ° C. Proceeds to 360 ° C. After that, the thermal decomposition of the polymer accompanied by endothermic starts from around 420 ° C., the flammable gases toluene and xylene are separated and finished at around 550 ° C., leaving 10% of the solid residue (ash content). Furthermore, in the novolak-type phenolic resin in a high-temperature fluid in which the atmosphere is blocked, desorption of the flammable plasticizer starts from around 260 ° C and continues until around 360 ° C, and then from 390 ° C, the polymer accompanied by heat absorption. Pyrolysis begins, producing flammable gases such as phenol and cresol, and ending at around 700 ° C., leaving 65% of the solid residue (ash content).
On the other hand, when a transparent conductive film is formed on a synthetic resin base material or part, the base material or part is covered with a mixture of fine crystals of a metal octylate compound and an organic compound. The temperature is raised to 290 ° C. At this time, the base material or the component is heated to 290 ° C. in a closed region where the atmosphere is blocked. Therefore, the thermal decomposition of the polymer is completely different from the thermal decomposition of the above-mentioned nitrogen gas, inert gas, or high-temperature fluid. That is, in nitrogen gas, an inert gas, and a high-temperature fluid, the gas generated by the thermal decomposition is sequentially released into the atmosphere or the high-temperature fluid, so that the thermal decomposition in which the gas is generated proceeds as the temperature rises. On the other hand, since the base material or component of the synthetic resin is shielded from the atmosphere and the temperature is raised in a closed region, the first gas produced by pyrolysis is confined in an extremely narrow region, and the gas in the narrow region The partial pressure increases, and the saturation pressure at that temperature is reached, and thermal decomposition stops. Therefore, in order to proceed with thermal decomposition, it is necessary to give the polymer greater thermal energy than thermal decomposition in an open atmosphere. Therefore, when a very small amount of gas is generated, the partial pressure of the gas in the narrow region becomes the saturation pressure at that temperature, and the amount of gas generated is extremely small as compared with the open atmosphere. Further, since the first gas is confined in the second and subsequent gases generated by the thermal decomposition, the thermal decomposition does not proceed unless a larger thermal energy is supplied. As a result, the synthetic resin in the region where the atmosphere is blocked and sealed is significantly higher in pyrolysis than the thermal decomposition temperature in the open atmosphere such as nitrogen gas, inert gas, and high temperature fluid, and octyl. Pyrolysis is performed at a temperature higher than the thermal decomposition temperature of the acid metal compound. Therefore, even if the fine crystals of the metal octylate compound are thermally decomposed, the polymer is not thermally decomposed and the properties of the synthetic resin do not change.

Example 1
In this embodiment, a transparent conductive coating material is produced using an inorganic metal compound that precipitates copper by thermal decomposition as a raw material. Inorganic metal compound as a copper raw material, tetraamine copper ions ^{_{[Cu (NH 3) 4]}} 2+ is a nitrate tetraamine copper nitrate _{[Cu (NH 3) 4]} (NO 3) 2 ( e.g., Mitsuwa Chemicals stock As the organic compound, diethylene glycol having a boiling point of 245 ° C. and a viscosity of 20 ° C. of 36 mPa sec (for example, a product of Mitsubishi Chemical Corporation) was used.
First, 51 g, which corresponds to 0.2 mol of tetraammine copper nitrate, is dispersed in methanol at a ratio of 10% by weight. Diethylene glycol was mixed with this dispersion at a ratio of 5% by weight to produce a transparent conductive coating material.

Example 2
Using the paint produced in Example 1, a laminate of copper fine particles was formed on the surface of a transparent film made of acrylic resin (for example, product number HBS006 of a product of Mitsubishi Rayon Co., Ltd.), and further, this laminate was formed. This is an example of forming a transparent conductive film covering the surface with a diethylene glycol film. The thickness of the acrylic resin transparent film is 50 μm.
The paint produced in Example 1 was screen-printed on the surface of 10 acrylic resin films cut to a size of 10 cm × 10 cm to a thickness of 20 microns (the printing machine uses, for example, a product MTVC_320 of Microtech Co., Ltd.). ). Further, the acrylic resin film was heat-treated in a hydrogen gas atmosphere. First, the temperature was raised to 75 ° C. to vaporize methanol. Next, it was left at 200 ° C. for 5 minutes to thermally decompose the tetraammine copper nitrate. This transparent film is used as sample 1.
For Sample 1, both a plurality of surfaces and a plurality of cut cross sections were observed with an electron microscope. As the electron microscope, an extremely low accelerating voltage SEM owned by JFE Techno Research Co., Ltd. was used. This device can observe the surface with an extremely low accelerating voltage from 100 volts , and can directly observe the surface of the sample without forming a conductive film.
First, secondary electron beams between 900-1000 volts of backscattered electron beams were extracted from various parts of a plurality of surfaces and a plurality of cross sections and subjected to image processing. Observation of the sample surface revealed that inside the diethylene glycol, a collection of granular fine particles having a size of 40-60 nm was present. In the observation of the cross section of the sample, granular fine particles were piled up on the surface of the transparent film with a thickness of about 10 layers, and a film covered with a diethylene glycol film was formed, and the film thickness was 1 μm.
Next, the energy between 900 and 1000 volts of the reflected electron beam from various parts of the plurality of surfaces and the plurality of cross sections was extracted and image processing was performed, and the material of the fine particles was examined by the shade of the image. No shading was observed in the granular fine particles, and they were composed of the same atoms.
Furthermore, the energy of characteristic X-rays from various parts on a plurality of surfaces and a plurality of cross sections and their intensities were image-processed, and the types of elements constituting the fine particles were analyzed. Since the granular fine particles were composed only of copper atoms, they are copper granular fine particles.
From the above observation results, about 10 aggregates of copper fine particles are stacked on the surface of the transparent film to form a laminated body of copper fine particles, and the surface of the laminated body is covered with a diethylene glycol film to form a film having a thickness of 1 μm. It turned out to be formed.
Further, the total light transmittance of the sample was measured by a haze meter (for example, spectroscopic haze meter model NDH7000 of Nippon Denshoku Industries Co., Ltd.). The acrylic resin transparent film used has a total light transmittance of 93% in the visible light wavelength region of 380 nm or more, but the prepared sample is 91% with respect to the incident light having a wavelength of 0.2-3 μm. The total light transmittance of is shown.
In addition, the surface resistance value of the sample surface was measured with a surface resistance meter (for example, surface resistance meter ST-4 of Simco Japan Co., Ltd.). The surface resistance value was 1 × 10 ⁵ Ω / □, and when a load of 30 g was applied to the sample surface, the surface resistance value decreased to less than 1 × 10 ³ Ω / □. Therefore, it was found that when a slight force was applied to the sample surface, the sample had a surface resistance closer to that of the metal thin film. Therefore, the inside of the diethylene glycol coating has a conductivity closer to that of metal.
From the observation and measurement results described above, the transparent conductive film formed on the surface of the transparent film can be used as a touch panel for detecting a touch operation with high sensitivity.
The above results are schematically shown in FIG. 1 as the cross-sectional structure of Sample 1. 1 is a transparent film of acrylic resin, 2 is copper fine particles, and 3 is diethylene glycol.

Example 3
In this example, aluminum octylate (C ₇ H ₁₅ COO) ₃ Al (for example, a product of Hope Pharmaceutical Co., Ltd.) is used as a raw material for precipitating aluminum by thermal decomposition, and dibutyl phthalate having a boiling point of 340 ° C. is used as an organic compound. C ₆ H ₄ (COO (CH ₂ ) ₃ CH ₃ ) ₂ (for example, a product of Showa Ether Co., Ltd.) is used to produce a transparent conductive paint.
First, 138 g, which corresponds to 0.3 mol of aluminum octylate, is dispersed in methanol at a rate of 10% by weight. Dibutyl phthalate was mixed with this dispersion at a ratio of 10% by weight to produce a transparent conductive coating material.

Example 4
Using the paint produced in Example 1, a laminate of aluminum fine particles was formed on the surface of a transparent film made of polyester resin (for example, brand PETG2 in the product of Teijin DuPont Film Co., Ltd.), and further, this laminate was formed. This is an example of forming a transparent conductive film in which the body is covered with a film of dibutyl phthalate. The thickness of the transparent film made of polyester resin is 50 μm. Further, the thermal decomposition of the polyester resin in the air atmosphere starts from around 400 ° C. Since the transparent film in this example is heated in a state of being coated with fine crystals of aluminum octylate and a film of dibutyl phthalate, the temperature at which the thermal decomposition of the transparent film starts is significantly higher than 400 ° C.
The paint produced in Example 3 was screen-printed on the surface of 10 polyester resin films cut into a size of 10 cm × 10 cm to a thickness of 10 μm. After that, heat treatment was performed in an air atmosphere. First, the temperature was raised to 75 ° C. to vaporize methanol, and then the temperature was allowed to stand at 290 ° C. for 1 minute to thermally decompose aluminum octylate. This transparent film is used as sample 2.
For Sample 2, both a plurality of surfaces and a plurality of cut cross sections were observed with an electron microscope in the same manner as in Example 2. From this observation result, about 15 collections of aluminum fine particles are stacked on the surface of the transparent film to form a laminated body of aluminum fine particles, and the surface of the laminated body is covered with a film of dibutyl phthalate to form a film having a thickness of 1 μm. Was found to be formed.
Further, the total light transmittance of the sample was measured by a haze meter in the same manner as in Example 2. The polyester resin transparent film used has a total light transmittance of 95.5% in the visible light wavelength region of 380 nm or more, but the prepared sample is 93 with respect to incident light having a wavelength of 0.2-3 μm. The total light transmittance of% was shown.
Moreover, the surface resistance value of the sample surface was measured by a surface resistance meter in the same manner as in Example 2. The surface resistance value was 1 × 10 ⁴ Ω / □, and when a load of 10 g was applied to the sample surface, the surface resistance value decreased to less than 1 × 10 ³ Ω / □. Therefore, it was found that when a slight force was applied to the sample surface, the sample had a surface resistance closer to that of the metal thin film. Therefore, the inside of the dibutyl phthalate coating has a conductivity closer to that of a metal. The reason why the surface resistance is lower than that of Example 2 is that the thickness of the dibutyl phthalate coating in this example is thinner than the thickness of the diethylene glycol coating in Example 2.
From the observation and measurement results described above, the transparent conductive film formed on the surface of the transparent film can be used not only as a touch panel for detecting touch operations with high sensitivity, but also as a transparent electrode for liquid crystal panels and solar cells. it can.
The above results are schematically shown in FIG. 2 as the cross-sectional structure of the sample 2. 4 is a transparent film made of polyester resin, 5 is fine aluminum particles, and 6 is dibutyl phthalate.

Although two examples related to the production of the transparent conductive paint and two examples related to the formation of the transparent conductive film have been described, the production of the transparent conductive paint and the formation of the transparent conductive film according to the present invention have been described. , Not limited to these examples for the following four reasons.
First, a transparent conductive coating material is produced by using a metal complex in which a molecule or an ion composed of an inorganic substance having a small molecular weight serves as a ligand and is coordinated to a metal ion different from copper. By using this transparent conductive coating material, a laminated body in which a collection of metal fine particles different from copper fine particles is stacked constitutes a transparent conductive film. Further, a transparent conductive coating material is produced by using a metal octylate compound instead of aluminum octylate. By using this transparent conductive paint, a laminated body in which a collection of metal fine particles different from aluminum fine particles is stacked constitutes a transparent conductive film. As described above, there are no restrictions on the material of the metal constituting the laminate in which the metal fine particles are stacked.
Secondly, the thickness of the laminate in which the metal fine particles are stacked can be freely changed according to the dispersion concentration of methanol of the metal complex or the metal octylate compound. Further, the thickness of the coating film of the organic compound can be freely changed depending on the viscosity and mixing ratio of the organic compound mixed with the methanol dispersion. As a result, the surface resistance of the transparent conductive film is brought closer to the surface resistance of the metal thin film. Further, since the laminated body in which the metal fine particles are stacked forms a path for continuous movement of electric charges, the inside of the coating of the organic compound exhibits conductivity closer to that of metal.
Third, metal fine particles of 40-60 nm, which are sufficiently smaller in size than the wavelength of 0.2-3 μm from near-ultraviolet to near-infrared, are stacked on the surface of the base material or parts to form a laminate. In addition, an organic compound having a refractive index between 1.4 and 1.5 for a wavelength of 0.2-3 µ m ranging from near-ultraviolet rays to near-infrared rays covers the laminate. To form a transparent conductive film, regardless of the material, shape, and size of the base material or parts, the surface of the base material or parts has high transparency to light from near-ultraviolet to near-infrared rays. A transparent conductive film having high transparency can be formed.
Fourth, the viscosity of low-viscosity conductive paint is finely adjusted according to the material, shape, and size of the base material or parts, and further, brush coating, roller coating, spray coating, dip coating, roll coater, etc. By selecting a coating method or a printing method such as bar coating, reverse coating, gravure printing, screen printing, etc., it is high for all substrates or parts against light ranging from the near-ultraviolet region to the near-infrared region. A transparent conductive film having a transmittance and high transparency, a conductivity close to that of metal, and a film thickness of about 1 μm can be formed.

1 Acrylic resin transparent film 2 Copper fine particles 3 Diethylene glycol 4 Polyester resin transparent film 5 Aluminum fine particles 6 Dibutyl phthalate

Claims (4)

A manufacturing method for producing a transparent conductive paint that forms a transparent conductive film on a base material or a part by applying or printing on the base material or the part is to disperse a metal compound that precipitates a metal by thermal decomposition in alcohol. , The metal compound is in a molecular state to prepare an alcohol dispersion liquid dispersed in alcohol, and the refractive index for light in the range from the near-ultraviolet region to the near-infrared region corresponding to a wavelength of 0.2-3 μm is 1. A first property having a value between .4-1.5, a second property having a melting point lower than 20 ° C., a third property that dissolves or mixes with the alcohol, and 10 times the viscosity of the alcohol. An organic compound having the fourth property having the above viscosity and the fifth property having a boiling point higher than the thermal decomposition temperature of the metal compound is mixed with the alcohol dispersion at a ratio of 10% by weight or less. The organic compound is dissolved or mixed with an alcohol to prepare a mixed solution in which the organic compound is uniformly mixed with the alcohol dispersion, whereby the mixed solution is applied to a base material or a component or printed to form the base. A method for producing a transparent conductive paint, wherein a transparent conductive paint composed of the mixed solution in which a transparent conductive film is formed on a material or a component is manufactured. The method of forming a transparent conductive film on the surface of a base material or a component using the transparent conductive coating material produced by the method according to claim 1 is to use the transparent conductive coating material produced by the method according to claim 1. , The surface of the base material or part is coated or printed, and the temperature of the base material or part is raised. First, the alcohol constituting the transparent conductive paint is vaporized, and the metal compound constituting the transparent conductive paint is used. A collection of fine crystals uniformly precipitates in the organic compound constituting the transparent conductive coating material, the fine crystals of the metal compound sink on the surface of the base material or the component, and the organic compound is the fine particles of the metal compound. It moves onto the crystal, after which the fine crystals of the metal compound are thermally decomposed, a collection of metal fine particles is piled up and deposited on the surface of the base material or the component, and the adjacent metal fine particles are metal-bonded to each other. A laminate in which the metal-bonded metal fine particles are stacked is formed on the surface of the base material or the component, and the organic compound having a boiling point higher than the thermal decomposition temperature of the metal compound forms the surface of the laminate. The first aspect of the present invention, wherein a transparent conductive film composed of a laminated body in which the metal fine particles are stacked and a coating film of the organic compound covering the surface of the laminated body is formed on the surface of the base material or the component. A method of forming a transparent conductive film on the surface of a base material or a component using a transparent conductive coating material produced by the method described. In the method for producing a transparent conductive coating material according to claim 1, the metal compound according to claim 1 comprises a metal complex ion in which an inorganic molecule or a ligand composed of an inorganic ion is coordinated and bonded to the metal ion. The inorganic metal compound to be contained, the alcohol according to claim 1 is methanol, and the organic compound according to claim 1 is any organic compound belonging to carboxylic acid esters, glycols or glycol ethers. The method for producing a transparent conductive paint according to claim 1, wherein the transparent conductive paint is produced according to the manufacturing method for producing a transparent conductive paint according to claim 1, using these three types of substances. In the method for producing a transparent conductive coating material according to claim 1, the metal compound according to claim 1 is a metal octylate compound, the alcohol according to claim 1 is methanol, and the organic according to claim 1. The compound is an organic compound belonging to carboxylic acid esters, and a transparent conductive coating material is produced according to the production method for producing a transparent conductive coating material according to claim 1, using these three types of substances. The method for producing a transparent conductive paint described.

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