JP2018059035A - Manufacturing method of transparent conductive coating and forming method of transparent conductive film using the coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a transparent conductive film having conductivity close to metal and film thickness around 1 μm on a surface of a substrate or a component on which a transparent conductive coating is applied or printed, further having high permeability and high transparency to a light from a near-ultraviolet region to near-infrared region.SOLUTION: A transparent conductive coating is manufactured by dispersing a metal compound which deposits metal by thermal decomposition in alcohol, and mixing an organic compound having refraction index of a value between 1.4 to 1.5, viscosity of 10 times or more of viscosity of alcohol, higher boiling point than thermal decomposition temperature of the metal compound and having these properties with the alcohol dispersion at 10 wt.% or less percentage. The transparent conductive coating is coated or printed on a surface of a substrate or a component, temperature of the substrate or the component is increased to volatilize the alcohol and further a temperature is increased till the metal compound is thermally decomposed, thereby a transparent conductive film is formed on a surface of the substrate or the component.SELECTED DRAWING: Figure 1

Description

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

In recent years, touch panels that have been used mainly for industrial devices such as station ticket machines, bank ATMs, and POS cash registers at convenience stores have come to be widely used in consumer devices such as smartphones, car navigation systems, and digital cameras. . There are four types of touch operation detection methods on the touch panel: a resistance film method, a surface capacitance method, a projection capacitance method, an optical method, and an ultrasonic 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 to cause a current to flow, thereby causing a change in voltage. This voltage change is detected to detect the touch position. Since it is pressure-sensitive, it can handle pen input, and its structure is simple, which makes it cheap to manufacture.
On the other hand, the capacitance method is a method in which a slight change in capacitance occurs when the panel is touched with a finger, and the touch position is detected from the change in capacitance. There are two types: surface type and projection type. . In the surface-type 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 corresponding to the distance to the touch position is generated at the electrodes at the four corners, and the touch position is detected from this weak current. The surface capacitance method is used for large panels and the like, but cannot support multi-touch that simultaneously detects a plurality of touch positions. The projection capacitive type that cleared this disadvantage and made multi-touch possible, and the panel had a structure in which two transparent conductive films with electrode patterns in the X-axis direction and Y-axis direction overlapped Have When a finger touches the panel, the capacitances of the conductive films arranged in a lattice pattern change simultaneously, and the touch position is detected by measuring this. The projection type has a more complicated structure than the surface type, but can detect the position with high accuracy, and can also handle multi-touch operations such as enlarging / reducing and rotating the photo on the screen with two fingers. It has been adopted for mobile devices such as smartphones and tablet PCs, and has become the mainstream of touch panels along with resistive film systems.
As described above, there are various types of touch panels, and a transparent conductive film is indispensable for any of the methods. Many of the transparent conductive films that have already been put into practical use are formed by applying a layer of ITO (abbreviation of Indium Tin Oxide, 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 technique for film formation.

Transparent conductive paint is applied to or printed on the surface of a substrate or component to form a transparent conductive film. Therefore, transparent conductive paint is formed at a significantly lower cost than transparent conductive films formed on a transparent substrate by sputtering. Can be formed. Moreover, it is used not only for a transparent conductive film in a touch panel, but also for an antistatic film or a surface antifouling film using conductivity. Furthermore, it can be used as a transparent electrode of a liquid crystal panel if conductivity close to metal is obtained, and as a transparent electrode of a solar cell if it has conductivity close to metal and the property of transmitting near-infrared to near-infrared light.
On the other hand, the higher the conductivity of the transparent conductive film and the thinner the film, the higher the sensitivity for detecting a touch operation on the touch panel. In particular, small touch panels used in smartphones, car navigation systems, digital cameras, and the like have a high detection sensitivity for touch operations, which is the product of such electronic devices. However, ITO has the highest conductivity among the transparent conductive materials, but its resistivity is 57 to 75 times higher than that of metal, for example, aluminum. Furthermore, the conductivity of the film formed of the paint in which ITO fine particles are dispersed is two orders of magnitude lower than the conductivity of the film that has been crystallized by heat-treating the ITO thin film formed by sputtering. 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 that makes it easy for ITO fine powders to come into contact with each other and to overlap. That is, while maintaining an aqueous solution of an indium salt and a tin salt in a turbulent state having a Reynolds number of 15000 or more, amino alcohol is added, and the deposited precipitate is baked at 300 ° C. to 800 ° C. to obtain an ITO having an aspect ratio of 5 A fine powder is produced. However, in order to increase the electrical conductivity of the film, the ITO fine powder must be in contact with each other, and the path through which the charges continuously move must be formed with the ITO fine powder, and the mixing ratio of the ITO fine powder must be increased. Don't be. However, the higher the mixing ratio of the ITO fine powder and the larger the aspect ratio of the ITO fine powder, the more the problem that the dispersibility of the ITO fine particles in the paint deteriorates.
Patent Document 2 describes a method for producing ITO fine particles having excellent dispersibility in a paint and a method for producing a paint in which the ITO fine particles are dispersed in a hydrophilic organic solvent. That is, 10 to 60 nm granular ITO fine particles produced by an arc plasma method, and an acrylate compound having two or more acryloyl groups or methacryloyl groups in the molecule and an ultraviolet curing property, alcohols, ethylene glycol mono A paint is produced by dispersing in alkyl ethers. However, in order to increase the conductivity of the film, the ITO fine particles must be in contact with each other, and a path through which electric charges continuously move must be formed by the ITO fine particles. However, due to the presence of the acrylate compound that is an insulator, the ITO fine particles come into contact with each other, and the path through which charges move by the ITO fine particles cannot be formed. In order to increase conductivity, it is necessary to increase the mixing ratio of ITO fine particles. However, the higher the mixing ratio, the higher the amount of expensive ITO fine particles produced by the arc plasma method increases. Since the ratio is low, there arises a problem that the smoothness of the film is inferior.

JP 2006-103984 A JP 2002-080754 A

A 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. For this reason, there is an essential problem related to the material composition of the paint, which consists of a problem caused by using the fine particles and a problem caused by dispersing the fine particles in the insulator vehicle.
That is, the first problem is that the binder as an insulator prevents the fine particles from contacting each other, and the resistance value of the coating film increases due to the presence of the binder.
The second problem is that the finer the fine particles, the worse the dispersibility of the fine particles in the vehicle, and the uneven distribution of the fine particles increases the resistance value of the coating film. On the other hand, if the mixing ratio of the fine particles in the vehicle is decreased, the dispersibility of the fine particles in the paint is increased, but the contact frequency between the fine particles in the paint film is lowered, and the resistance value of the paint film is increased.
Furthermore, the third problem is that the finer the particles, the more easily the fine particles are aggregated. As a result, the dispersibility of the fine particles in the vehicle deteriorates, and as a result, the resistance value of the coating film increases. On the other hand, if the mixing ratio of the fine particles into the vehicle is reduced, the aggregation of the fine particles is less likely to occur, but the frequency of contact between the fine particles in the coating film decreases, and the resistance value of the film increases.
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 completely different from the material structure of the conventional transparent conductive paint. Solvable. For this reason, realization of the transparent conductive paint which consists of a new material structure is calculated | required strongly. The problem to be solved by the present invention is that a transparent conductive film having a conductivity close to metal and having a film thickness of about 1 μm is formed on a substrate or a component coated or printed with a transparent conductive paint. It is to realize a conductive paint and a transparent conductive film. Another object of the present invention is to realize a transparent conductive film having high transparency and high transparency with respect to light from the near ultraviolet region to the near infrared region using this transparent conductive paint.

  In the production method for producing a transparent conductive paint according to the present invention, a metal compound that deposits a metal by pyrolysis is dispersed in alcohol to produce an alcohol dispersion, and the wavelength ranging from the near ultraviolet region to the near infrared region is 0. A first property having a refractive index between 1.4 and 1.5 for light of 2 μm to 3 μm, a second property having a melting point lower than 20 ° C., and a third property that dissolves or mixes in the alcohol. An organic compound having both the above properties, the fourth property having a viscosity of 10 times or more of the viscosity of the alcohol, and the fifth property having a boiling point higher than the thermal decomposition temperature of the metal compound in the alcohol dispersion. This is a method for producing a transparent conductive paint in which a mixed liquid is prepared by mixing at a ratio of 10% by weight or less, whereby a transparent conductive paint comprising the mixed liquid is produced.

That is, according to this production method, when a metal compound that deposits a metal by pyrolysis is first dispersed in alcohol, the metal compound is in a molecular state and is dispersed in the alcohol by about 10% by weight. As a result, the metal raw material is converted into a liquid phase. Next, when the organic compound is mixed in the alcohol dispersion at a ratio of 10% by weight or less, the organic compound is dissolved or mixed in the alcohol. Therefore, the organic compound is uniformly mixed with the alcohol dispersion and has a low viscosity. 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 applied with brush, roller, spray coating, dip coating, roll 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 substrates or parts will have a coating film or a film thickness depending on the viscosity. A printed film is formed. On the other hand, the low-viscosity paint applied to or printed on the base material or part enters the surface irregularities of the base material or part, and forms a coating film or printed film on the surface of the base material or part.

  A method for forming a transparent conductive film on the surface of a substrate or a part using the transparent conductive paint produced by the above-described production method is to apply or print the transparent conductive paint on the surface of a substrate or a component, The substrate or the component is heated to vaporize the alcohol, and further heated to a temperature at which the metal compound is thermally decomposed. As a result, a collection of metal fine particles is accumulated and deposited on the surface of the substrate or the component. A transparent conductive film in which the adjacent metal fine particles are metal-bonded and the laminate in which the metal-bonded metal fine particles are stacked is coated with a high-boiling organic compound is formed on the surface of the base material or the component. This is a method for forming a transparent conductive film.

In other words, when a transparent conductive paint is applied to or printed on a substrate or part, the paint is a low-viscosity liquid, so the coating film or printed film is thin, and the paint is applied to the unevenness of the surface of the substrate or part. Get in. Thereafter, when heat treatment is performed, the alcohol that occupies most of the coating film or the printed film is vaporized first to form a very thin coating film or printed film. 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 deposited in the organic compound. On the other hand, since the density of the fine crystal of the metal compound is higher than the density of the organic compound, the fine crystal of the metal compound sinks on the surface of the substrate or component, and the organic compound moves onto the collection of fine crystals of the metal compound. Moreover, since the size of the fine crystal of the metal compound is one digit or more smaller than the unevenness of the surface of the base material or component, the fine crystal enters the unevenness of the surface and covers the surface. The fine crystal of the metal compound corresponds to the size of the metal fine particles precipitated by thermal decomposition. When the temperature is further increased, thermal decomposition of fine crystals of the metal compound occurs on the surface of the substrate or component. At this time, the metal compound is decomposed into a metal and an inorganic or organic substance, and the inorganic or organic substance is vaporized by taking the heat of vaporization, and at the moment when the vaporization of the inorganic or organic substance is completed, the granular compound having a size of 40 nm to 60 nm is obtained. A collection of metal fine particles accumulates on the surface of the base material or component and precipitates. Since the metal fine particles are precipitated in an active state having no impurities, adjacent metal fine particles are metal-bonded to each other, and a laminate in which metal-bonded metal fine particles are stacked is formed on the surface of the base material or component. This laminated body enters the unevenness of the surface of the base material or component and covers the surface of the base material or component. For this reason, a laminated body does not peel from the surface of a base material or components by an anchor effect. On the other hand, the organic compound whose boiling point is 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 with a thickness of about 1 μm is formed on the surface of the substrate or component. It is formed.
This film is composed of a laminate in which metal fine particles bonded with metal are stacked and a film of an organic compound on the surface layer, and this film enters the irregularities on 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 organic compound film, and the film is not peeled off. Also, even if a person touches the film, the existence of the film is not known. Furthermore, since the vapor pressure of the organic compound at room temperature is extremely small, it does not evaporate over a long period of time. On the other hand, a laminate in which metal-bonded metal particles are stacked forms a path through which electric charges move continuously, and an insulating organic compound is formed on the surface layer as an extremely thin film. Is close to the conductivity of the metal. Furthermore, since the laminate is shielded from the outside by an organic compound film, the laminate does not change with time, and the conductivity of the film does not change over a long period of time.
This film has a high transmittance for incident light. That is, when light is incident on the film, surface reflection occurs on the surface of the film due to the difference in refractive index between the film and air. Since the surface of the film is composed of an organic compound film, incident light causes surface reflection according to the difference in refractive index between the organic compound and air. This surface reflectance is the square of the value obtained by dividing the difference in 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 total incident light is 1. Since the refractive index of the organic compound has a refractive index of 1.4 to 1.5 for light having a wavelength ranging from the near ultraviolet region to the near infrared region of 0.2 μm to 3 μm, the incident light from the near ultraviolet region to the near infrared region The surface reflectance is 3 to 4%, the transmittance is 92 to 94%, and light ranging from near ultraviolet to near infrared is transmitted through 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 10 paragraphs.
Furthermore, the light transmitted through the surface of the film is scattered by the laminate in which metal fine particles are stacked. The scattering of light in the fine particles is scattered 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 greatly 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 nm to 60 nm is sufficiently smaller than the wavelength of incident light of 0.2 μm to 3 μm, the scattering coefficient of the metal fine particles is extremely small, and the coating shows high transparency. Rayleigh scattering will be described again in the following 11th paragraph.
Thus, the film formed of the transparent conductive paint has high transmittance and high transparency with respect to light in a region extending from the near ultraviolet region to the near infrared region. Further, the conductivity of the film has a conductivity close to that of a metal and is as thin as about 1 μm. Therefore, this film becomes a transparent conductive film. This solved the problem described in the fifth paragraph.
In some cases, a functional film accompanying firing is formed on a transparent conductive film formed on the surface of a substrate or 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 a fine powder of a metal oxide semiconductor is applied to the surface of the transparent conductive film and baked at a temperature of 400 ° C. or higher to form a porous metal oxide semiconductor film. When baking the paste, the organic compound forming the surface layer of the transparent conductive film is vaporized. In addition, since the laminated body in which the metal fine particles are stacked is heated to a temperature higher than the temperature at which the metal fine particles are deposited, the metal fine particles obtain thermal energy and take in the adjacent metal fine particles, so that the metal fine particles grow. When the temperature is raised by 100 ° C. from the temperature at which the metal fine particles are deposited, the metal fine particles grow and the volume of the metal fine particles increases by nearly 5%. Although the number of fine particles is reduced by the growth of the metal fine particles, the grown metal fine particles are metal-bonded to each other to form a laminate in which the grown metal fine particles are stacked. Even when the metal fine particles grow, there is no light scattering because the size of the metal fine particles is sufficiently small compared to the wavelength of near ultraviolet to near infrared rays. Thus, the glass substrate having a transparent conductive film formed on the surface can be used as a transparent electrode of a dye-sensitized solar cell without losing the function of the transparent conductive film even if it is baked.
On the other hand, the method for producing a transparent conductive paint and the method for forming a transparent conductive film in the present invention provide various excellent effects.
First, the production of a transparent conductive coating consists of only two very simple steps in which an organometallic compound is dispersed in alcohol and the organic compound is mixed with the alcohol dispersion. If the two steps are carried out in succession, a transparent conductive paint can be produced in large quantities at a low cost.
Secondly, the process of forming the transparent conductive film is a process of vaporizing alcohol and then thermally decomposing the metal compound only by heat treatment, and the transparent conductive film can be manufactured at low cost.
Third, the raw materials for the transparent conductive paint are a metal compound, an alcohol and an organic compound, all of which are general industrial chemicals. Further, since expensive transparent conductive fine particles are not used, a transparent conductive film that is significantly less expensive than the conventional one can be manufactured.
Fourth, even if the surface of the base material or parts is contaminated with dust, particulate contaminants called dust, or oily contaminants consisting of organic substances, it vaporizes when pyrolyzing metal compounds. Removed. Further, even if the contaminant cannot be removed by thermal decomposition of the metal compound, the laminate composed of a collection of metal fine particles is formed over the remaining contaminant, so that the conductivity of the laminate does not change. In addition, since the laminate is covered with a film of an organic compound, new contaminants and substances that cause chemical changes do not adhere to the laminate, and the conductivity of the laminate does not change with time. Accordingly, it is not necessary to clean the surface of the base material or parts in advance.
Fifth, the viscosity of the transparent conductive paint produced is low. For this reason, the viscosity of the paint is finely adjusted according to the material, shape, and size of the base material or component, and further, a coating method such as brush coating, roller coating, spray coating, dip coating, roll coater, or By selecting a printing method such as bar coating, reverse coating, gravure printing, screen printing, etc., all substrates and parts have high transmittance and high transparency for light ranging from the near ultraviolet region to the near infrared region. In addition, a transparent conductive film having a conductivity close to that of a metal and having a thickness of about 1 μm can be formed. As a result, a touch panel that detects touch with high sensitivity, a liquid crystal panel, a transparent electrode of a solar cell, and the like can be manufactured 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 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 at the surface of the 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 Equation 2 consisting of 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 the wavelength ranging from the near ultraviolet region to the near infrared region is 1.4 to 1.5, the surface reflectance R is 3 to 4%, and the total light transmittance T is 92 to 94%. Thus, light ranging from the near-ultraviolet region to the near-infrared region is transmitted through the surface of the film with a transmittance comparable to that of float glass.

Next, light scattering will be described. 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 nm to 60 nm are sufficiently small with respect to the wavelength of 0.2 μm to 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 the light scattering. . In Equation 3, S is the scattering coefficient, λ is the wavelength of incident light, D is the particle diameter, and m is the ratio of the refractive index of the metal fine particles to the refractive index of the organic compound. Further, π is a circumference ratio. The scattering coefficient S in Equation 3 greatly depends on the fourth power of the ratio D / λ of the particle diameter D to the wavelength λ of 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 ranging from the near ultraviolet region to the near infrared region.

  The first raw material used when manufacturing the transparent conductive paint described above is an inorganic metal having a metal complex ion in which the metal compound is a ligand composed of an inorganic molecule or ion coordinated to a metal ion. A compound, wherein the alcohol is methanol, and the organic compound is any organic compound composed of carboxylic acid esters, glycols or glycol ethers.

That is, the inorganic metal compound having a metal complex ion is thermally decomposed in a reducing atmosphere at 180 ° C. to 220 ° C. to deposit a metal. Moreover, it disperse | distributes to methanol near 10weight%. For this reason, an inorganic metal compound becomes a raw material which deposits a metal by thermal decomposition. Therefore, a transparent conductive film can be formed on a base material or component having a heat resistance in a reducing atmosphere of 220 ° C. or higher.
That is, since a ligand composed of an inorganic molecule or ion has a low molecular weight, when an inorganic metal compound having a metal complex ion in which a ligand is coordinated to a metal ion is heat-treated in a reducing atmosphere, a coordination bond portion is obtained. Is divided at a temperature lower than 180 ° C. to 220 ° C. and decomposed into an inorganic substance and a metal. When the temperature is further increased, the inorganic substance vaporizes by evaporating heat, and after the vaporization of all the inorganic substances is completed, the metal is deposited at 180 ° C. to 220 ° C. That is, the metal ion located at the center of the molecule is the largest among the ions constituting the inorganic metal compound. For this reason, the distance between the metal ion and the ligand is the longest. Accordingly, when the inorganic metal compound is heat-treated in a reducing atmosphere, the coordination bond portion where the metal ion is bonded to the ligand is first divided. As such an inorganic metal compound, ammonia NH ₃ becomes a ligand and an ammine complex coordinated to a metal ion, water H ₂ O becomes a ligand and an aqua complex coordinated to a metal ion, chlorine Chloro complex in which ion Cl ⁻ or chlorine ion Cl ⁻ and ammonia NH ₃ serve as ligands and coordinate bond to metal ions, and cyano complex in which cyano group CN ⁻ serves as ligand ions and coordinate bonds to metal ions Examples thereof include a complex, a bromo complex in which bromine ion Br ⁻ serves as a ligand ion and coordinates to a metal ion, and an iodine complex in which iodine ion I ⁻ serves as a ligand ion and coordinates to a metal ion.
Next, in the carboxylic acid esters, glycols or glycol ethers, first, the refractive index with respect to the wavelength of 0.2 μm to 3 μm extending from the near ultraviolet ray region to the near infrared region is 1.4 to 1.5. Second, the melting point is lower than 20 ° C., third, dissolved or mixed in methanol, fourth, a viscosity more than 10 times the viscosity of methanol, and fifth, the temperature at which the inorganic metal compound is thermally decomposed There are organic compounds that combine these five properties with higher boiling points. Such organic compounds are all general industrial chemicals.
Therefore, when such an organic compound is mixed in a methanol dispersion of an inorganic metal compound, the organic compound is dissolved or mixed in methanol, so that the organic compound is uniformly mixed with the methanol dispersion of the inorganic metal compound. When this mixed solution is applied to or printed on a substrate or part, and the inorganic metal compound is thermally decomposed by raising the temperature, a collection of particulate metal fine particles having a size of 40 to 60 nm is formed on the surface of the substrate or part. It accumulates and precipitates. Thereby, a laminate in which metal fine particles are stacked is formed. At this time, an organic compound having a boiling point higher than the thermal decomposition temperature remains, and a transparent conductive film in which a laminate of metal fine particles is covered with a small amount of an organic compound is formed. For this reason, an organic compound becomes a raw material of a transparent conductive paint.

  The second raw material used in manufacturing the transparent conductive paint described above is that the metal compound described above is an octylic acid metal compound, the alcohol described above is methanol, and the organic compound described above is a carboxylic acid ester. It is an organic compound to which it belongs.

That is, the metal octylate is thermally decomposed at 290 ° C. to deposit a metal. Moreover, it disperse | distributes to methanol near 10weight%. Therefore, the metal octylate compound becomes a raw material for depositing metal by thermal decomposition. When a base material or part made of synthetic resin is covered with a transparent conductive film by thermal decomposition of an octylate metal compound, the base material or part is covered with a collection of fine crystals of the octylate metal compound and an organic compound. In this state, the temperature is raised to 290 ° C. At this time, the base material or component is heated to 290 ° C. while being blocked by the atmosphere, so that the synthetic resin does not thermally decompose. Therefore, the surface of the base material or 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, the metal ion is the largest among the ions constituting the metal octylate compound. Therefore, in the octylic acid 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 heat-treating the octylate metal compound having such a molecular structure, when the boiling point of octylate is exceeded, the bond between the oxygen ion and the metal ion constituting the carboxyl group is first divided and separated into octylate and metal. Furthermore, octylic acid takes the heat of vaporization and vaporizes, and when vaporization is completed, metal is deposited. As such organometallic compounds, there are carboxylic acid metal compounds such as lauric acid metal compounds and stearic acid metal compounds in addition to octylic acid metal compounds. On the other hand, at atmospheric pressure, octyl acid has a boiling point of 228 ° C., lauric acid has a boiling point of 296 ° C., and stearic acid has a boiling point of 361 ° C. Therefore, since the thermal decomposition temperature of the octylic acid metal compound composed of octylic acid having the lowest boiling point is the lowest, the heat treatment cost of the transparent conductive paint can be reduced by using the octylic acid metal compound.
Furthermore, octylic acid metal compounds are inexpensive industrial chemicals that can be easily synthesized. That is, when octylic acid is reacted with a strong alkali, an alkali metal octylate is produced. Thereafter, when the alkali metal octylate compound is reacted with an inorganic metal compound, metal octylate compounds composed of various metals are synthesized. Therefore, it is the cheapest organometallic compound among the organometallic compounds.
Next, the organic compound belonging to the carboxylic acid ester has a refractive index of 1.4 to 1.5 with respect to a wavelength of 0.2 μm to 3 μm extending from the near ultraviolet region to the near infrared region, The melting point is lower than 20 ° C, the third is dissolved or mixed in methanol, the fourth has a viscosity of 10 times or more of the viscosity of methanol, and the fifth has a boiling point higher than 290 ° C. There are organic compounds. Such organic compounds are general-purpose industrial chemicals.
When such an organic compound is mixed with a methanol dispersion of an octylate metal compound, the organic compound is dissolved or mixed in methanol, and thus the organic compound is uniformly mixed with the methanol dispersion of the octylate metal compound. When this mixed solution is applied to or printed on a substrate or a component, and the metal octylate is thermally decomposed by heating, a collection of particulate metal fine particles having a size of 40 nm to 60 nm is formed on the substrate or the component. It accumulates on the surface and precipitates. Thereby, a laminate composed of a collection of metal fine particles is formed. On the other hand, an organic compound having a boiling point higher than 290 ° C. remains, and a transparent conductive film in which a laminate of metal fine particles is covered with a small amount of an organic compound is formed. For this reason, an organic compound becomes a raw material of a transparent conductive paint.

It is a figure which illustrates typically the cross section of the transparent conductive film by which the laminated body which consists of a collection of copper fine particles was coat | covered with the film which consists of diethylene glycol on the surface of the transparent film of an acrylic resin. It is a figure which illustrates typically the cross section of the transparent conductive film by which the laminated body which consists of a collection of aluminum microparticles | fine-particles was coat | covered with the film which consists of dibutyl phthalate on the surface of the transparent film of a polyester resin.

Embodiment 1

As an embodiment of a metal compound that deposits a metal by heat treatment, an inorganic metal compound having a metal complex ion in which a ligand consisting of an inorganic molecule or ion is coordinated to a metal ion has a relatively low thermal decomposition temperature. Explain that it is suitable as a metal compound. Here, the copper compound which deposits copper which is excellent in electrical conductivity and thermal conductivity next to silver by pyrolysis will be described.
In order for a copper compound to be a raw material for a transparent conductive paint, it is necessary to have both a property of dispersing in alcohol and a property of depositing 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 into the alcohol. Therefore, after the alcohol is vaporized, fine crystals of the inorganic copper compound do not precipitate. In addition, low molecular weight inorganic copper compounds such as copper oxide, copper chloride, and copper sulfide are not dispersed in alcohols. For this reason, these low molecular weight inorganic copper compounds are not dispersed in alcohol.
Among chemical reactions in which copper is produced from a copper compound, the thermal decomposition reaction is the simplest chemical reaction. That is, copper precipitates only by raising the temperature of the copper compound. Furthermore, if the thermal decomposition temperature of the copper compound is low, a transparent conductive film can be formed on a substrate or 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 is reduced because the molecule or ion consisting of an inorganic substance is a ligand, and the molecular weight of the inorganic ligand is small. The temperature at which pyrolysis is performed in the atmosphere is lower than the temperature at which the organocopper compound in which an organic substance having a higher molecular weight forms a ligand thermally decomposes in an air atmosphere. Such a copper complex is a material that is relatively more expensive than an organic copper compound, but a transparent conductive film can be formed on a substrate or component having low heat resistance.
That is, the copper ion is the largest among the molecules constituting the copper complex. Incidentally, the covalent bond radius of copper atoms is 132 ± 4 pm, while the covalent bond radius of nitrogen atoms is 71 ± 1 pm, and the covalent bond radius of oxygen atoms is 66 ± 2 pm. For this reason, in the molecular structure of a copper complex, the distance of the coordinate bond part in which a ligand coordinates-bonds to a copper ion is the longest. Therefore, in the heat treatment in a reducing atmosphere, the coordination bond is first divided and decomposed into copper and an inorganic substance, and copper is deposited after the vaporization of the inorganic substance is completed.
Among such copper complexes, ammonia NH ₃ serves as a ligand to form an ammine complex that coordinates to a copper ion, chlorine ion Cl ⁻ , or chlorine ion Cl ⁻ and ammonia NH ₃ serve as a ligand. Thus, the chloro complex coordinated to the copper ion is easier to synthesize than other copper complexes, and 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 thermal decomposition is completed at a relatively low temperature of about 200 ° C. Further, it is dispersed in methanol to a dispersion concentration of nearly 10% by weight. Examples of such copper complex ^ions include tetraammine copper complex ions [Cu (NH ₃ ) ₄ ] ²⁺ or hexaammine copper complex ions [Cu (NH ₃ ) ₆ ] ²⁺ , and examples of copper complexes include tetraammine copper. (II) Nitrate [Cu (NH ₃ ) ₄ ] (NO ₃ ) ₂ or hexaammine copper (II) sulfate [Cu (NH ₃ ) ₆ ] SO ₄
As described above, as a material for the copper compound to thermally decompose at a relatively low temperature to precipitate copper, a copper complex ion in which a ligand consisting of an inorganic molecule or ion is coordinated to a copper ion is used. A copper complex is suitable. As a result, a transparent conductive film can be formed on the surface of a substrate or component having low heat resistance.

Embodiment 2

As another embodiment of the metal compound for depositing a metal by heat treatment, it will be described that an octylic acid metal compound is appropriate. The metal compound used as the raw material for the transparent conductive coating material has two properties of first dispersing in methanol and precipitating the metal by the second pyrolysis. Here, it will be explained that aluminum octylate is appropriate as a material having aluminum as a metal and having two properties. Aluminum has a density as small as 2.70 g / cm ³ and has excellent properties of conductivity and thermal conductivity next to silver, copper, and gold. Therefore, by using aluminum octylate as a raw material, a transparent conductive film that is lightweight and excellent in conductivity and thermal conductivity can be formed.
First, an aluminum compound dispersed in alcohol will be described. Aluminum chloride dissolves in water and hydrolyzes into aluminum hydroxide and hydrochloric acid. Aluminum hydroxide is not dispersed in alcohol. Furthermore, aluminum sulfate is dissolved in alcohol, and aluminum ions are eluted. Aluminum oxide is not dispersed in alcohol. For this reason, these low molecular weight inorganic aluminum compounds are not dispersed in alcohol.
Note that an aluminum complex having an aluminum complex ion coordinated and bonded to an aluminum ion located in the center of the molecular structure is a thermal decomposition because aluminum oxide precipitates aluminum oxide. It does not become a raw material for depositing aluminum by decomposition. Examples of such an aluminum complex include an aqua complex having a water molecule H ₂ O as a ligand and a hydroxo complex having a hydroxide ion OH ⁻ as a ligand.
Next, the organoaluminum compound precipitates aluminum by thermal decomposition. Among the chemical reactions in which aluminum is produced from an organoaluminum compound, the chemical reaction by the simplest treatment is a thermal decomposition reaction. That is, aluminum is deposited only by raising the temperature of the organoaluminum compound. Furthermore, if the synthesis of the organoaluminum compound is easy, it can be manufactured 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 at 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. This is because the covalent bond radius of aluminum ion atoms is 121 ± 4 pm, the covalent bond radius of oxygen ion atoms is 66 ± 2 pm, and the covalent bond radius of carbon atoms is 73 pm. Therefore, an aluminum carboxylate compound in which an aluminum ion and an oxygen ion constituting a carboxyl group are covalently bonded has a bonding portion between the aluminum ion having the longest bond distance and the oxygen ion constituting the carboxyl group at the boiling point of the carboxylic acid. It is divided first and separated into aluminum and carboxylic acid. When the temperature is further increased, if the carboxylic acid is a saturated fatty acid, the carboxylic acid takes the heat of vaporization and vaporizes, and aluminum is deposited after the vaporization of the carboxylic acid is completed. Examples of such an aluminum carboxylate compound include aluminum octylate, aluminum laurate, and aluminum stearate. Many of such aluminum carboxylate compounds are inexpensive industrial chemicals marketed as metal soaps.
Moreover, the aluminum carboxylate compound is easy to synthesize. That is, when a carboxylic acid is reacted in a strong alkali solution such as sodium hydroxide, a carboxylic acid alkali metal 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.
Furthermore, if the boiling point of the saturated fatty acid is low, the aluminum carboxylate compound composed of saturated fatty acid is thermally decomposed at a low temperature, and the heat treatment cost for precipitating aluminum can be low. When the hydrocarbon constituting the saturated fatty acid has a long chain structure, the longer the long chain, that is, the higher the molecular weight of the saturated fatty acid, the higher the boiling point of the saturated fatty acid. Incidentally, the boiling point at atmospheric pressure of lauric acid having a molecular weight of 200.3 is 296 ° C., and the boiling point of stearic acid having a molecular weight of 284.5 at 361 ° C. is 361 ° C. Therefore, an aluminum carboxylate compound composed of a saturated fatty acid having a relatively low molecular weight is desirable as a raw material for depositing aluminum because the thermal decomposition temperature is relatively low.
Furthermore, 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 comprising a saturated fatty acid having a branched chain structure is thermally decomposed at a low temperature. In addition, since saturated fatty acids having a branched chain structure are polar, aluminum carboxylates composed of saturated fatty acids having a branched chain structure are also polar and disperse in a relatively high proportion in organic solvents having a polarity such as alcohol. . Octyl acid is a saturated fatty acid having such a branched structure. That is, octylic acid has a structural formula represented by CH ₃ (CH ₂ ) ₃ CH (C ₂ H ₅ ) COOH, and is branched into an alkane of CH ₃ (CH ₂ ) ₃ and C ₂ H ₅ with CH. Carboxyl group COOH binds. The boiling point of octylic acid at atmospheric pressure is 228 ° C., which is 68 ° C. lower than the boiling point of lauric acid. For this reason, aluminum octylate having a low thermal decomposition temperature is desirable as a raw material for depositing aluminum. Aluminum octylate is thermally decomposed at 290 ° C. in an 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, so that when the carboxylic acid aluminum compound composed of the unsaturated fatty acid is thermally decomposed, an oxide of aluminum is deposited. In addition, an aluminum carboxylate compound in which the oxygen ion constituting the carboxyl group becomes a ligand and approaches the aluminum ion to form a coordinate bond, the distance between the aluminum ion and the oxygen ion is shortened. The distance between the ion and the ion bonded on the opposite side is the longest. In such a thermal decomposition reaction of an aluminum carboxylate compound, a bonded portion between an oxygen ion and an ion bonded on the opposite side of the aluminum ion is first divided, and as a result, aluminum oxide is precipitated.
Here, copper octylate is used as the metal octylate compound, and the thermal decomposition reaction in both the air atmosphere and the nitrogen atmosphere is performed at 5 ° C./min. This will be described from the TG-DTA characteristics in which the temperature is increased at a rate of temperature increase. The TG characteristic is a result of continuously measuring the weight change of copper octylate accompanying a temperature rise, and the DTA characteristic is a temperature difference between the reference substance and a thermal change generated in copper octylate with a temperature rise. Is the result of differential thermal analysis detected as In both the air and nitrogen atmospheres, after the gradual weight loss due to the removal of moisture is finished, when the boiling point of octyl acid exceeds 228 ° C, a clear weight loss appears, and the weight rapidly decreases with increasing temperature. Thermal decomposition proceeds. That is, in the air atmosphere, the calorific value increased rapidly at 278.8 ° C., the peak of the calorific value 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 the nitrogen atmosphere, the calorific value increased rapidly at 285.3 ° C., the peak of the calorific value appeared at 289.0 ° C., the exothermic phenomenon ended at 291.3 ° C., and the weight decreased by 77.4%. Therefore, the thermal decomposition of copper octylate has no problem in considering that the thermal decomposition starts at the boiling point of octylic acid and ends at 290 ° C. and precipitates copper in both the air atmosphere and the nitrogen atmosphere. Moreover, since the theoretical weight reduction | decrease of the copper octylate which copper precipitates by thermal decomposition of copper octylate is 81.8 weight%, it is safe to think that copper precipitated by thermal decomposition.

Embodiment 3

  In the present embodiment, first, the refractive index for a wavelength of 0.2 μm to 3 μm extending from the near ultraviolet region to the near infrared region has a value of 1.4 to 1.5, and secondly, the melting point is lower than 20 ° C., Thirdly, it is dissolved or mixed in methanol. Fourth, it has a viscosity of 10 times or more than that of methanol. Fifth, the temperature at which the metal complex composed of inorganic metal compounds is thermally decomposed. It is an embodiment relating to an organic compound having these five properties, which has a boiling point higher than the temperature at which it is heated. 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 seconds at 20 ° C. The refractive index described below is a representative value of the refractive index for sodium D-line (wavelength: 589.3 nm) at 20 ° C., and any organic compound is 0.2 μm from the near ultraviolet region to the near infrared region. The refractive index for a wavelength of ˜3 μm is between 1.4 and 1.5 with only a slight change in the fourth digit of the significant figure.

First, carboxylic acid esters will be described. Carboxylic acid esters are classified 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 composed of the first saturated carboxylic acid, a carboxylic acid ester dissolved in methanol and having a melting point lower than 20 ° C. and a boiling point between 200 ° C. and 290 ° C. is butyl caproate having a boiling point of 207 ° C. It is a carboxylic acid ester having the above molecular weight. However, the viscosity of such carboxylic acid esters is less than 10 times that of methanol.
Among esters composed of saturated carboxylic acids, carboxylic acid esters that are dissolved in methanol and have a melting point lower than 20 ° C. and a boiling point higher than 290 ° C. are higher than ethyl myristate having a boiling point of 295 ° C. Carboxylic acid esters having a molecular weight. Incidentally, ethyl myristate has a viscosity at 20 ° C. of 6 mPa seconds and a refractive index of 1.436. Accordingly, esters composed of a metal octylate compound, methanol, and a saturated carboxylic acid having a molecular weight equal to or higher than ethyl myristate are used as raw materials for the transparent conductive paint.
Next, among the esters composed of the second unsaturated carboxylic acid, a carboxylic acid ester that has a property of being dissolved in methanol and having a melting point lower than 20 ° C. and a boiling point higher than 290 ° C. has a molecular weight higher than that of methyl oleate. Carboxylic acid ester having Incidentally, 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 an octylic acid metal compound, methanol, and an unsaturated carboxylic acid having a molecular weight equal to or higher than that of methyl oleate are used as raw materials for the transparent conductive paint.
Furthermore, among esters composed of a third aromatic carboxylic acid, a carboxylic acid ester that is dissolved in methanol and has a melting point lower than 20 ° C. and a boiling point between 200 ° C. and 290 ° C. has a molecular weight higher than that of ethyl benzoate. 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 benzoates is less than 10 times that of methanol.
Among esters of aromatic carboxylic acids, carboxylic acid esters that are dissolved or mixed in methanol and have a melting point lower than 20 ° C. and a boiling point higher than 290 ° C. have a molecular weight higher than that of diethyl phthalate. Carboxylic acid ester. Incidentally, 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 to 1.495. Furthermore, the viscosity of dioctyl phthalate having a boiling point of 385 ° C. is 81.4 mPa seconds at 20 ° C., and the refractive index is 1.485 at 25 ° C. Therefore, esters composed of a metal compound of octylate, methanol, and an aromatic carboxylic acid having a molecular weight equal to or higher than diethyl phthalate are used as raw materials for the transparent conductive paint.

Next, glycols will be described. There are six types of glycols, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, and tripropylene glycol. These glycols are all liquid monomers that are dissolved or mixed in methanol and have a melting point lower than 20 ° C.
Diethylene glycol has a boiling point of 244 ° C., a viscosity at 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 to 1.434. Furthermore, dipropylene glycol has a boiling point of 232 ° C., a viscosity at 25 ° C. of 75 mPa seconds, and a refractive index of 1.440 to 1.442. Tripropylene glycol has a boiling point of 265 ° C., a viscosity at 25 ° C. of 57.2 mPa seconds, and a refractive index of 1.442. Therefore, the inorganic metal compound having a metal complex ion, methanol, and the above-described glycols become raw materials for the transparent conductive paint.

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 each terminal 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 lower than 20 ° C.
First, an ethylene glycol ether having a boiling point between 200 ° C. and 290 ° C. has a boiling point of 229 ° C., a viscosity of 20 ° C. of 7.6 mPas, a refractive index of 1.4316 and 2-ethylhexyl glycol, Is 231 ° C., 20 ° C. viscosity is 6.5 mPa seconds, refractive index is 1.436 buzyl diglycol, boiling point is 245 ° C., 20 ° C. viscosity is 30.5 mPa seconds, and refractive index is 1. 539 phenyl glycol, boiling point 249 ° C., 20 ° C. viscosity 7.5 mPa seconds, refractive index 1.427 methyltriglycol, boiling point 256 ° C., 20 ° C. viscosity 12 mPa seconds, A benzyl glycol having a refractive index of 1.523, a boiling point of 259 ° C., a viscosity of 20 ° C. of 8.6 mPa seconds, a refractive index of 1.437, a boiling point of 271 ° C., and a boiling point of 20 ° C. There are butyl triglycol having a degree of 8.1 mPa seconds and a refractive index of 1.438, and 2-ethylhexyl glycol having a boiling point of 272 ° C., a viscosity at 20 ° C. of 10.4 mPa seconds and a refractive index of 1.442. . Therefore, the inorganic metal compound having a metal complex ion, methanol, and the above glycol ethers become raw materials for the transparent conductive paint.
Further, ethylene glycol 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 become raw materials for the transparent conductive paint.
Next, a propylene glycol ether having a boiling point between 200 ° C. and 290 ° C. has a boiling point of 231 ° C., a viscosity at 20 ° C. of 7.4 mPa seconds, and a refractive index of 1.426, A phenylpropylene glycol having a boiling point of 243 ° C., a viscosity of 20 ° C. of 23.2 mPa seconds and a refractive index of 1.524, a boiling point of 274 ° C., a viscosity of 20 ° C. of 8.2 mPa seconds and a refractive index of 1.428 butyl propylene triglycol. Therefore, the inorganic metal compound having a metal complex ion, methanol, and the above glycol ethers become raw materials for the transparent conductive paint.

Embodiment 4

Here, whether or not a transparent conductive film can be formed on a base or part of a synthetic resin 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 with the thermal decomposition of the metal octylate compound, a transparent conductive film can be formed on the base material or part of the synthetic resin.
By the way, the thermal decomposition reaction of the polymer constituting the synthetic resin is greatly different between an atmosphere in which oxygen gas exists and a nitrogen atmosphere. That is, the thermal decomposition of the polymer in the atmosphere in which oxygen gas is present is accompanied by heat generation because it is thermal decomposition due to an oxidation reaction. This exothermic phenomenon promotes thermal decomposition of a polymer made of an organic substance that is easily oxidized. On the other hand, in the thermal decomposition in a nitrogen atmosphere, no oxidation reaction occurs, thermal decomposition due to endothermic reaction occurs, and no exothermic phenomenon occurs. For this reason, 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 oxygen gas exists. For example, thermal decomposition of a high-density polyethylene resin starts near 250 ° C. in an air atmosphere, but starts near 400 ° C. in a nitrogen atmosphere, and shifts to 150 ° C. on the high temperature side.
The thermal decomposition of other polymers in a nitrogen atmosphere starts at 280 ° C. and ends at 420 ° C. for the polyacetal resin POM. The polystyrene resin PS starts thermal decomposition at 350 ° C. and ends at around 460 ° C. Polyethylene terephthalate resin PET starts thermal decomposition at 425 ° C. and ends at around 480 ° C. The polypropylene resin PP begins to decompose at 370 ° C. and ends at around 500 ° C. The high-density polyethylene resin HDPE starts thermal decomposition at 400 ° C. and ends at around 520 ° C. The polytetrafluoroethylene resin PTFE starts thermal decomposition at 490 ° C. and ends at around 640 ° C.
Polyvinyl chloride resin PVC in a helium gas atmosphere starts from around 220 ° C. with an endothermic reaction, and the flammable and harmful hydrogen chloride gas and the flammable gases benzene and naphthalene start off at around 260 ° C. And continue to 360 ° C. Thereafter, thermal decomposition of the polymer with endotherm starts from around 420 ° C., and the combustible gases toluene and xylene are removed and the reaction is terminated at around 550 ° C., leaving a solid residue (ash content) of 10%. Furthermore, the novolak type phenolic resin in the high temperature fluid in which the atmosphere is shut off begins to desorb the flammable plasticizer from around 260 ° C. and continues to around 360 ° C., and thereafter, from 390 ° C. Pyrolysis begins, combustible gases such as phenol and cresol are generated, and the process ends at around 700 ° C., leaving a solid residue (ash content) of 65%.
In contrast, when a transparent conductive film is formed on a synthetic resin substrate or component, the substrate or component is covered with a mixture of fine crystals of metal octylate and an organic compound. The temperature is raised to 290 ° C. At this time, the base material or component is heated to 290 ° C. in a sealed region where the atmosphere is shut off. For this reason, the thermal decomposition of the polymer is completely different from the above-described thermal decomposition with nitrogen gas, inert gas, or high-temperature fluid. That is, in the case of nitrogen gas, inert gas, or 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 parts of the synthetic resin are shielded from the atmosphere and heated in a sealed area, the first gas generated by pyrolysis is confined in a very narrow area, and the gas in the narrow area is trapped. The partial pressure increases, resulting in a saturation pressure at that temperature, and thermal decomposition stops. Therefore, in order to proceed with the thermal decomposition, it is necessary to give the polymer a higher thermal energy than the thermal decomposition in an open atmosphere. For this reason, 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 compared to the open atmosphere. Moreover, since the first gas is confined in the second and subsequent gases generated by the thermal decomposition, the thermal decomposition does not proceed unless larger thermal energy is supplied. As a result, the synthetic resin in the sealed area where the atmosphere is shut off and the thermal decomposition proceeds remarkably on the higher temperature side than the thermal decomposition temperature in the released atmosphere such as nitrogen gas, inert gas or high-temperature fluid described above, and octyl Pyrolysis occurs at a temperature higher than the thermal decomposition temperature of the acid metal compound. Therefore, even if the fine crystals of the metal octylate are thermally decomposed, the polymer is not thermally decomposed and the properties of the synthetic resin are not changed.

In this example, a transparent conductive paint is produced using an inorganic metal compound that precipitates copper by pyrolysis as a raw material. The inorganic metal compound used as a raw material of copper is tetraammine copper ion [Cu (NH ₃ ) ₄ ] ²⁺ nitrate, tetraammine copper (II) nitrate [Cu (NH ₃ ) ₄ ] (NO ₃ ) ₂ (for example, Mitsuwa The organic compound used was diethylene glycol having a boiling point of 245 ° C. and a viscosity of 20 m ° C. for 36 mPa seconds (for example, a product of Mitsubishi Chemical Corporation).
First, 51 g corresponding 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 paint.

Using the coating material manufactured in Example 1, a laminate in which copper fine particles are stacked is formed on the surface of a transparent film made of an acrylic resin (for example, product number HBS006 manufactured by Mitsubishi Rayon Co., Ltd.). This is an example in which a transparent conductive film is formed by covering the film with a film of diethylene glycol. The film thickness of the acrylic resin transparent film is 50 μm.
The coating material produced in Example 1 was screen-printed with a thickness of 20 μm on the surface of 10 acrylic resin films cut to a size of 10 cm × 10 cm (the printing machine uses, for example, a product MTVC — 320 manufactured by Microtec Corporation). Furthermore, 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 tetraammine copper nitrate. This transparent film is designated as Sample 1.
For sample 1, both the plurality of surfaces and the plurality of cut sections were observed with an electron microscope. As the electron microscope, an extremely low acceleration voltage SEM owned by JFE Techno-Research Corporation was used. This apparatus can observe the surface with an extremely low acceleration voltage from 100 V, and can directly observe the surface of the sample without forming a conductive film.
First, a secondary electron beam between 900 V to 1 kV of the reflected electron beam was taken out from various portions of a plurality of surfaces and a plurality of cross sections, and image processing was performed. In observation of the sample surface, a collection of granular fine particles having a size of 40 nm to 60 nm was present inside diethylene glycol. In observation of the cross section of the sample, granular fine particles were stacked on the surface of the transparent film with a thickness of about 10 layers, and a film with a diethylene glycol film covering the surface was formed, and the film thickness was 1 μm.
Next, image processing was performed by extracting energy between 900 V to 1 kV of reflected electron beams from various parts of a plurality of surfaces and a plurality of cross sections, and the material of the fine particles was examined based on the density of the image. The granular fine particles were not composed of light and shade, and were composed of the same atoms.
Furthermore, the energy and intensity of characteristic X-rays from various parts of a plurality of surfaces and a plurality of cross sections were subjected to image processing, and the types of elements constituting the fine particles were analyzed. Since the particulate fine particles are composed only of copper atoms, they are copper particulate fine particles.
From the above observation results, about 10 pieces of copper fine particles are stacked on the surface of the transparent film to form a laminated body of copper fine particles, and a film having a thickness of 1 μm is formed by covering the surface of the laminated body with a film of diethylene glycol. It was found that it was formed.
Furthermore, the total light transmittance of the sample was measured with a haze meter (for example, a spectroscopic haze meter model NDH7000 manufactured by Nippon Denshoku Industries Co., Ltd.). The used acrylic resin transparent film 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 incident light having a wavelength of 0.2 μm to 3 μm. The total light transmittance was shown.
Moreover, the surface resistance value of the sample surface was measured with the 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 further had a surface resistance close to that of a metal thin film. For this reason, the inside of the coating of diethylene glycol has a conductivity closer to that of a 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 that detects touch operations with high sensitivity.
The above results are schematically shown in FIG. 1 is a transparent film of acrylic resin, 2 is copper fine particles, and 3 is diethylene glycol.

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

Using the coating material produced in Example 1, a laminated body in which aluminum fine particles are stacked is formed on the surface of a transparent film made of polyester resin (for example, brand PETG2 from Teijin DuPont Films Co., Ltd.). It is an Example which forms the transparent conductive film which covers a body with the film of a dibutyl phthalate. The film thickness of the polyester resin transparent film is 50 μm. Further, 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 where it is covered with the fine crystals of aluminum octylate and the dibutyl phthalate film, the temperature at which the thermal decomposition of the transparent film starts is significantly higher than 400 ° C.
The coating material produced in Example 3 was screen-printed with a thickness of 10 μm on the surface of 10 polyester resin films cut to a size of 10 cm × 10 cm. Thereafter, heat treatment was performed in an atmospheric atmosphere. First, the temperature was raised to 75 ° C. to vaporize methanol, and then left at 290 ° C. for 1 minute to thermally decompose aluminum octylate. This transparent film is designated as Sample 2.
For Sample 2, both the plurality of surfaces and the plurality of cut sections were observed with an electron microscope in the same manner as in Example 2. From this observation result, a collection of about 15 aluminum fine particles are stacked on the surface of the transparent film to form a laminate of aluminum fine particles, and the surface of the laminate is covered with a film of dibutyl phthalate to form a film having a thickness of 1 μm. It was found that was formed.
Further, the total light transmittance of the sample was measured with a haze meter in the same manner as in Example 2. The transparent film of the polyester resin 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 for incident light with a wavelength of 0.2 μm to 3 μm. % Of the total light transmittance.
Further, the surface resistance value of the sample surface was measured with a surface resistance meter in the same manner as in Example 2. The surface resistance value was 1 × 10 ⁴ Ω / □, and when a 10 g load 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 further had a surface resistance close to that of a metal thin film. For this reason, the inside of the coating of dibutyl phthalate has a conductivity closer to that of a metal. The reason why the surface resistance was lower than that in Example 2 was that the thickness of the diphthyl phthalate film in this example was thinner than the thickness of the diethylene glycol film 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. 4 is a transparent film of polyester resin, 5 is aluminum fine particles, and 6 is dibutyl phthalate.

Two examples relating to the production of transparent conductive paints and two examples relating to the formation of transparent conductive films have been described, but the production of transparent conductive paints and the formation of transparent conductive films according to the present invention are as follows. However, the present invention is 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 ion made of an inorganic substance having a low molecular weight serves as a ligand and is coordinated to a metal ion different from copper. By using this transparent conductive paint, a laminate in which a collection of metal fine particles different from copper fine particles is stacked constitutes a transparent conductive film. Moreover, a transparent conductive coating material is manufactured by using an octylic acid metal compound instead of aluminum octylate. By using this transparent conductive paint, a laminate in which a collection of metal fine particles different from aluminum fine particles is stacked constitutes a transparent conductive film. Thus, there is no restriction | limiting of the material of the metal which comprises the laminated body on which the metal microparticles were piled up.
Secondly, the thickness of the laminate in which metal fine particles are stacked can be freely changed according to the methanol concentration of the metal complex or octylate metal compound. Furthermore, the thickness of the organic compound coating can be freely changed according to the viscosity and mixing ratio of the organic compound mixed in the methanol dispersion. As a result, the surface resistance of the transparent conductive film can be made closer to the surface resistance of the metal thin film. Moreover, since the laminated body in which metal fine particles are stacked forms a path through which electric charges move continuously, the inside of the organic compound film shows conductivity closer to that of a metal.
Thirdly, the metal fine particles composed of 40 nm to 60 nm whose particle size is sufficiently smaller than the wavelength of 0.2 μm to 3 μm extending from near ultraviolet rays to near infrared rays are stacked on the surface of the base material or component to be a laminate. In addition, an organic compound having a refractive index of 1.4 to 1.5 covers the top of the laminate with respect to a wavelength of 0.2 μm to 3 μm ranging from near ultraviolet to near infrared. Because it forms a transparent conductive film, it is highly transparent and highly transparent to light ranging from near-ultraviolet rays to near-infrared rays, regardless of the material, shape, or size of the substrate or component. A transparent conductive film having properties can be formed.
Fourth, finely adjust the viscosity of the low-viscosity conductive paint according to the material, shape, and size of the base material or parts, and further apply brush coating, roller coating, spray coating, dip coating, roll coater, etc. By selecting the coating method or printing method such as bar coating, reverse coating, gravure printing, screen printing, etc., it is high for all base materials or parts with respect to light ranging from the near ultraviolet region to the near infrared region. A transparent conductive film having a transmittance and high transparency and having a conductivity close to that of a metal and having a film thickness of about 1 μm can be formed.

1 Transparent film of acrylic resin 2 Copper fine particles 3 Diethylene glycol 4 Transparent film of polyester resin 5 Aluminum fine particles 6 Dibutyl phthalate

Claims (4)

  The production method for producing a transparent conductive paint is a method in which a metal compound in which metal is deposited by thermal decomposition is dispersed in alcohol to create an alcohol dispersion, and the wavelength ranging from the near ultraviolet region to the near infrared region is 0.2 μm to A first property having a refractive index between 1.4 and 1.5 for light of 3 μm, a second property having a melting point lower than 20 ° C., and a third property that dissolves or mixes in the alcohol 10% by weight of an organic compound having a fourth property having a viscosity 10 times or more the viscosity of the alcohol and a fifth property having a boiling point higher than the thermal decomposition temperature of the metal compound in the alcohol dispersion. A method for producing a transparent conductive paint, wherein a mixed liquid is prepared by mixing at the following ratio, whereby a transparent conductive paint comprising the mixed liquid is produced.   A method for forming a transparent conductive film on the surface of a substrate or a component is as follows. The transparent conductive paint produced by the method according to claim 1 is applied or printed on the surface of a substrate or a component. The temperature of the component is increased to evaporate the alcohol, and the temperature is increased to a temperature at which the metal compound is thermally decomposed. The transparent conductive film in which the metal fine particles are metal-bonded and the laminate in which the metal-bonded metal fine particles are stacked is coated with a high-boiling organic compound is formed on the surface of the substrate or the component. A method for forming a transparent conductive film.   The first raw material used in producing the transparent conductive paint according to claim 1 is a metal compound according to claim 1 wherein a ligand composed of an inorganic molecule or ion is coordinated to a metal ion. An inorganic metal compound having a metal complex ion, wherein the alcohol according to claim 1 is methanol, and the organic compound according to claim 1 is any one of carboxylic acid esters, glycols or glycol ethers It is an organic compound, The 1st raw material used when manufacturing the transparent conductive coating material of Claim 1 characterized by the above-mentioned.   The second raw material used when producing the transparent conductive paint according to claim 1 is such that the metal compound according to claim 1 is an octylate metal compound, and the alcohol according to claim 1 is methanol, The organic compound according to claim 1 is an organic compound belonging to carboxylic acid esters, and is a second raw material used when producing the transparent conductive paint according to claim 1.

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