TWI597335B - A method of forming an ITO conductive film-forming coating and an ITO conductive film - Google Patents

Description

Coating method for forming ITO conductive film and method for forming ITO conductive film

The present invention relates to a coating material for forming an ITO conductive film capable of suppressing an increase in resistance value of an ITO conductive film under high temperature and high humidity. In the present specification, ITO means Indium Tin Oxide.

In a display device such as an LCD (Liquid Crystal Display), a PDP (Plasma Display Panel), or an organic EL (Electro Luminescence) touch panel, a transparent electrode is used. The transparent electrode is usually composed of a transparent conductive material containing ITO or the like. Such a transparent electrode is usually formed into a film shape by a sputtering method or the like (for example, refer to Patent Document 1). However, the sputtering apparatus is expensive, and has a problem that the film forming efficiency is poor and the film is liable to be cracked. As a method of forming an ITO conductive film having excellent flexibility in which cracking is unlikely to occur, a method of applying a coating material for forming an ITO conductive film to a substrate has been proposed instead of the sputtering method. However, if the transparent electrode obtained by the coating method is placed under high temperature and high humidity, the electric resistance value tends to increase due to oxygen and moisture in the environment, which has become a cause of deterioration in reliability.

In order to solve this problem, as an ITO guide according to the coating method In the coating material for forming an electric film, a transparent conductive material comprising a surface-treated conductive powder obtained by treating a surface of a conductive powder such as ITO powder having water resistance with a surface treatment agent and a transparent conductive material of a curable compound (for example, Reference is made to Patent Document 2) or a transparent conductive material containing a resin, a transparent conductive particle such as ITO powder, a ceria material, and a decane coupling agent (for example, refer to Patent Document 3).

Prior technical literature Patent literature

Patent Document 1: Japanese Laid-Open Patent Publication No. 2004-315951 (paragraph [0002])

Patent Document 2: Japanese Laid-Open Patent Publication No. 2006-59772 (abstract, claim 1)

Patent Document 3: Japanese Laid-Open Patent Publication No. 2009-135044 (Summary, Request Item 1)

The transparent electrode of the ITO conductive film formed of the transparent conductive material described in the above Patent Documents 2 and 3 can sufficiently suppress the increase in the resistance value due to the influence of moisture even under high temperature and high humidity. However, in recent years, the use of a transparent electrode is more diversified, and it is required to suppress a coating material for forming an ITO conductive film which can increase the resistance value of a transparent electrode under high temperature and high humidity even under more severe conditions than in the past.

An object of the present invention is to provide a coating material for forming an ITO conductive film capable of suppressing an increase in the electric resistance value of a transparent electrode including an ITO conductive film under high temperature and high humidity even under more severe conditions than in the prior art.

According to a first aspect of the invention, there is provided a coating material for forming an ITO conductive film, comprising: an ITO powder; a dispersion medium of the ITO powder; and a surface treatment agent for the ITO powder, wherein the dispersion medium is an alcohol solution, and the surface treatment agent The phthalic acid ester having an alkyl group having 2 or less carbon atoms, or the surface treatment agent is a decane coupling agent having an amine group or a fluorenyl group at the terminal group, and the phthalate ester contains 1% based on 100% by mass of the ITO powder. 30% by mass, or the decane coupling agent is contained in an amount of 0.1 to 30% by mass based on 100% by mass of the ITO powder.

A second aspect of the present invention is the coating material for forming an ITO conductive film according to the first aspect of the invention, wherein the phthalic acid ester is tetramethoxy decane having an alkyl group having 1 carbon atom or an alkane having 2 carbon atoms Base tetraethoxy decane.

A third aspect of the present invention is the coating material for forming an ITO conductive film according to the first aspect of the invention, wherein the decane coupling agent is N-2-(aminoethyl)-3-aminopropyltrimethoxydecane, 3- Aminopropyltrimethoxydecane, 3-mercaptopropylmethyldimethoxydecane or 3-mercaptopropyltrimethoxydecane.

According to a fourth aspect of the invention, there is provided a method of forming an ITO conductive film using the coating material according to any one of the first to third aspects.

Originally, In ₂ O ₃ , which is a main component of ITO, has a structure of a bixbyite, and can be expressed as a structure in which oxygen is regularly deoxidized from a fluorite structure. When the amount of Sn as a dopant in the structure is increased or the like, a structure in which oxygen is easily absorbed between the crystal lattices is obtained. Therefore, if the ITO powder is placed under high temperature and high humidity, water adsorbed on the surface of the powder will combine as an oxygen vacancie or crystal lattice on the surface of the powder, and will trap carrier electrons, thereby reducing the ITO powder. Electrical conductivity.

In the coating material for forming an ITO conductive film according to the first aspect of the present invention, a specific amount of phthalic acid ester having an alkyl group having a carbon number of 2 or less or a specific amount of decane having an amine group or a fluorenyl group at the terminal group is used. The coupler surface treatment agent treats the surface of the ITO powder. The above phthalate ester is an organic hydrazine compound (Si-O-R, but R is an alkyl group) having one or more ester bonds between hydrazine and a hydrocarbon chain. Further, the above decane coupling agent has an amine group or a fluorenyl group at the terminal group.

When treated with such a surface treating agent, it is considered that in the case of the above phthalate ester, a phthalate is bonded between an oxygen vacancy and a crystal lattice on the surface of the powder, or in the case of the above decane coupling agent. By combining an amine group or a sulfhydryl group between the oxygen vacancies and the crystal lattice on the surface of the above powder, the stability against water is greatly improved, respectively. Further, on the surface of the general ITO, -OH is already present on the surface of the particles. Therefore, by incorporating the above-described phthalate ester or the above-described decane coupling agent, the trapped electrons are released and an effect of improving conductivity is obtained. As a result, the coating material of the present invention can suppress an increase in the electric resistance value of the ITO conductive film formed of the coating material under high temperature and high humidity.

10‧‧‧Multicrystalline ITO particles

11‧‧‧ rod center nucleus

12‧‧‧ rods

1 is a schematic view of polycrystalline ITO particles of the ITO powder of the present invention. (a) is a schematic perspective view, and (b) is a schematic cross-sectional view.

Fig. 2 is a photographic view showing an aspect of the polycrystalline ITO particles and ITO powder of the present invention taken by TEM. (a) is a 10,000-fold photo map, and (b) is a 50,000-time photo map.

Next, an embodiment for carrying out the invention will be described based on the drawings.

<ITO powder>

As schematically shown in (a) and (b) of FIG. 1, the ITO powder of the present invention contains polycrystalline ITO particles 10. The polycrystalline ITO particles 10 include a rod-shaped central core 11 and a plurality of rod-shaped bodies 12, and are integrally formed such that a plurality of rod-like bodies 12 surround the rod-shaped central core in substantially the same direction as the longitudinal direction of the rod-shaped central core 11. 11. Further, as shown in the photographic diagram of Fig. 2, in the polycrystalline ITO particles, a plurality of short rod-like bodies such as twigs can be observed, and it can be observed that the short rod-like bodies surround the rod-shaped central core and mutually Adjacent, and arranged in the same direction and fixed to the rod-shaped central core. Further, as shown in FIG. 2, the respective diameters and lengths of the plurality of rod-shaped bodies are not necessarily the same, and the cross-sectional shape and the surface shape thereof are not necessarily the same.

The average length L of the polycrystalline ITO particles 10 of the present invention is In the range of 0.2 to 5.0 μm, it is preferably in the range of 1.0 to 5.0 μm. When the average diameter of the polycrystalline ITO particles 10 is D, L/D is in the range of 2 to 20, preferably in the range of 3 to 10. When L is less than 0.2 μm, it is easy to stand perpendicular to the surface of the substrate on which the ITO conductive film is formed, and it is impossible to obtain an effect that is easy to fall like a football. When L exceeds 5.0 μm, the packing property between the particles is deteriorated. In addition, when L/D is less than 2, the effect of improving conductivity by anisotropy cannot be obtained, and when it exceeds 20, when the coating film is produced, the rod-shaped particles are broken and shortened.

Since the polycrystalline ITO particles of the ITO powder of the present invention have the above-described shape, for example, when a coating ITO film is produced, when the coating material containing the ITO powder is applied while being applied to the resin film, it is easy to be aligned in the coating direction. Resin film surface. That is, the polycrystalline ITO particles are likely to roll on the surface of the resin film and lie on their sides. Further, since the ITO particles of the present invention are polycrystalline, as a result of a moderate deviation at the grain boundaries, voids between the particles are easily filled, and the polycrystalline ITO particles become dense. As a result, when the ITO particles of the present invention are used for a material such as a transparent electrode, good electrical conductivity can be obtained by further reducing the electric resistance. In addition, when the polycrystalline ITO particles are filled and applied to the transparent substrate and the film, the coating layer becomes a dense structure, whereby the light-receiving surface of the thin film solar cell and the transparent electrode of the optical device can be obtained. The light transmittance is good and the haze is lowered.

<Method for Producing ITO Powder>

Hereinafter, a method for producing the ITO powder of the present invention will be described.

First, as a first step, weigh and mix the tin salt in a specific ratio. And an indium salt, the mixture is dissolved in pure water to be a mixed solution of a tin salt and an indium salt, and the mixed solution is reacted with a base to form a suspension of tin-containing indium hydroxide. As a mixing method, a method of adding a base such as ammonia to a mixed aqueous solution of a tin salt and an indium salt is preferred. When a base is added to a mixed aqueous solution of a tin salt and an indium salt, anisotropic particles are easily formed, and by controlling the temperature, the addition rate, and/or the particle concentration at the time of adding a base, the size of the produced hydroxide particles can be controlled or Axis ratio.

Further, in the present invention, ultrasonic waves of a specific frequency are irradiated to the above-mentioned reaction liquid in the mixing. By imparting the ultrasonic wave, it is possible to manufacture an ITO powder including polycrystalline ITO particles, that is, a plurality of ITO rod-like bodies shorter than the ITO rod-like central core are integrally formed around the ITO rod-shaped central core. The ITO rod-shaped central core has the same direction in the longitudinal direction and surrounds the ITO rod-shaped central core. The frequency of the ultrasonic wave is set to 20 to 10000 kHz. When the frequency is less than 20 kHz, the agitation effect of the ultrasonic wave is weak. On the other hand, if it exceeds 10,000 kHz, the output power of the ultrasonic wave is lowered, and a sufficient effect cannot be obtained. The frequency is better set to 20~1000kHz.

The specific time at which the ultrasonic wave is applied to the above suspension needs to be appropriately adjusted by the frequency, the capacity of the neutralizing liquid, and the like. For example, when the frequency of the ultrasonic wave is 100 kHz, when the capacity of the reaction liquid is 1 L, the time for dropping the alkali while irradiating the ultrasonic wave is preferably 20 to 600 minutes. If the application time of the ultrasonic wave is too short, there is a problem that the effect of the ultrasonic irradiation cannot be sufficiently obtained, and if it is too long, the particle may become too long. The liquid level of the reaction liquid is set to be the same as the liquid level of the ultrasonic irradiation device (the medium that transmits the ultrasonic wave from the irradiation device to the reactor) so that the ultrasonic waves are both It is uniformly applied to the reaction liquid. By imparting the ultrasonic wave, it is possible to obtain polycrystalline ITO particles which are a plurality of ITOs which are shorter than the central core by preventing the aggregation of the anisotropic ITO particles from each other while being aggregated. The rod is fixed in the same direction as the longitudinal direction of the ITO rod-like central core and surrounds the ITO rod-like central core.

Among them, as the salt of tin and indium, a hydrochloride, a sulfate, or a nitrate is used, but a hydrochloride is usually preferable. Further, ammonia, caustic soda, caustic potash or the like carbonate is used as the base, but from the viewpoint of reducing impurities after the slurry of the tin-containing indium hydroxide is formed, ammonia is preferably used.

The resulting slurry of tin-containing indium hydroxide is collected by solid-liquid separation, and impurities are washed by pure water to obtain a bulk of tin-containing indium hydroxide having high purity. The obtained cake is dried at room temperature or higher, preferably at a temperature of 80 ° C or higher, to obtain a dry powder of tin-containing indium hydroxide.

In the case of tin-containing indium hydroxide, there is also a case where tin is substituted for indium hydroxide, but there are cases where tin oxide and/or tin hydroxide are coprecipitated with indium hydroxide, and it is also present as tin oxide and/or Or a case where tin hydroxide and indium hydroxide become an amorphous mixture.

As described above, the particle size of the tin-containing indium hydroxide is determined in the step of obtaining the hydroxide. Specifically, by controlling the reaction temperature in the range of 40 to 90 ° C, respectively, the reaction time (the time required for total neutralization) is controlled within a range of 20 to 600 minutes, and the final particle concentration is controlled to 0.01 to 3 mol. Within the range of /L, it is possible to obtain the desired particles The tin-containing indium hydroxide of the diameter.

In the case where, for example, rod-shaped particles of tin-containing indium hydroxide having an average length L of polycrystalline ITO particles of 1 μm and an average diameter D of 0.2 μm are synthesized, the reaction temperature is set to 60 ° C, and the reaction time (all neutralization) The time required is set to 75 minutes, and the final particle concentration is set to 0.5 mol/L. On the other hand, when particles of rod-shaped particles having an average length smaller than that of tin-containing indium hydroxide are produced, the reaction temperature is set to be low, or the reaction time is set to be short or the particle concentration is set to be high. Further, the size of the finally formed polycrystalline ITO particles is roughly determined by the size of the tin-containing hydroxide. That is, when the tin-containing hydroxide is converted into ITO particles, the average length L and the average diameter D both shrink by about 70 to 80%.

Next, the procedure of the tin-containing indium hydroxide obtained by the firing in the second step will be described. The purpose of this firing step is to form ITO as an oxide from tin-containing indium hydroxide and to impart oxygen defects to the obtained ITO crystal. Thus, this baking step is performed in a weakly reducing environment in which an inert gas and a reducing gas are mixed in order to impart oxygen defects to the crystal of ITO. Usually, as a weakly reducing environment, a mixed gas obtained by mixing hydrogen or carbon monoxide, ammonia, and an alcohol into an inert gas such as nitrogen or helium or argon is used. The mixing ratio of each gas in the mixed gas is appropriately determined by the amount of oxygen deficiency of the crystal to be imparted to the ITO. However, if the reducing power of the mixed gas is too strong, the tin-containing indium hydroxide becomes InO, metal In, or the like. Further, the mixing ratio of hydrogen and carbon monoxide or the like is preferably a concentration at which the mixed gas does not exceed the explosion limit in the atmosphere.

In the firing step, the firing is first performed, followed by Restore processing. In the firing, the tin-containing indium hydroxide is dehydrated to become indium oxide. The firing temperature is 300 to 1000 °C. When it is 300 ° C or more, a complete oxide can be obtained. When it is 1000 ° C or less, severe sintering between ITO particles can be avoided. Preferably, the firing temperature is 350 to 800 ° C or less. The firing time is preferably 0.1 hours or longer, but once the dehydration reaction is completed, it is not necessary to perform further firing. The environment is set to atmosphere.

The reduction treatment after the firing is preferably carried out at a temperature of 200 ° C or more and less than 500 ° C in the above-mentioned reducing atmosphere. When it is 200 ° C or more, oxygen deficiency can be provided, and if it is less than 500 ° C, since an appropriate reducing power can be obtained, insulating InO is not formed. The reduction treatment time is 0.5 to 5 hours. If it is less than 0.5 hours, the formation of oxygen defects is insufficient, and even if it exceeds 5 hours, no favorable change will occur. Through the above steps, an ITO powder containing the ITO particles of the present invention can be obtained. In the ITO powder fired in the mixed gas in which the alcohol is mixed with the inert gas, since the OH group on the surface of the powder is large, the phthalate or decane coupling agent which is a surface treatment agent described later is easily bonded to the OH group. Therefore, the surface treatment by the phthalate or decane coupling agent has a higher effect, and the increase in the electric resistance of the ITO conductive film under high temperature and high humidity can be further suppressed.

<Method for Producing Coating Material for Forming ITO Conductive Film>

The ITO powder was mixed at a ratio of 1 to 70% by mass based on 100% by mass of the alcohol-based solution to which the surface treatment agent was added, and the coating material for forming an ITO conductive film was prepared by stirring with a stirrer. Wherein, the surface treatment agent is a phthalic acid ester having an alkyl group having a carbon number of 2 or less, or the surface treatment agent has an amine group at the terminal group (-R-NH ₂ , -R-NHR, -R-NR ¹ R ² Or a decane coupling agent based on fluorenyl (-R-SH). Wherein R, R ¹ and R ² are each an alkyl group. The phthalic acid ester having 2 or less carbon atoms in the alkyl group is exemplified by tetramethoxy decane or tetraethoxy decane. Further, as a decane coupling agent having an amine group or a mercapto group at the terminal group, N-2-(aminoethyl)-3-aminopropyltrimethoxydecane, 3-aminopropyltrimethoxydecane, and 3- are exemplified. Methyl propyl dimethoxy decane or 3-mercaptopropyl trimethoxy decane. Further, the phthalate ester of the present invention preferably has a network composed of SiO ₂ and has a plurality of ester bonds after being bonded to the surface of the particles.

When the surface treatment agent is phthalic acid ester, the concentration of the phthalic acid ester in the coating material is 1 to 30% by mass based on 100% by mass of the ITO powder. Further, when the surface treatment agent is a decane coupling agent, the concentration of the decane coupling agent in the coating material is 0.1 to 30% by mass based on 100% by mass of the ITO powder. When the amount of each of the blending amounts is less than the lower limit value, the effect of suppressing an increase in the electric resistance value of the ITO conductive film under high temperature and high humidity cannot be obtained. In addition, when the ITO conductive film is formed, the surface treatment agent hinders contact between the ITO particles and causes an initial surface resistance to increase.

As the dispersion medium of the ITO powder, an alcohol-based solution such as ethanol, 2-butanol or 1-propanol is exemplified. The ITO powder is added and mixed in an amount of from 1 to 70% by mass based on 100% by mass of the alcohol-based solution. When it is less than 1% by mass, it is difficult to form a film having a sufficient thickness in the conductive film, and if it exceeds 70% by mass, the viscosity of the dispersion is high and coating is difficult. And, if necessary, the above-mentioned ITO conductive film forming paint is placed in a homogenizer and a bead mill In the pulverizer or the like, the ITO powder in the coating material is pulverized. Further, a binder such as cerium oxide sol-gel or acrylic resin may be added to the coating material for forming an ITO conductive film as long as the electric resistance is not deteriorated.

<Method for Producing ITO Conductive Film>

The ITO conductive film is produced, for example, according to the following method. A substrate for forming an ITO conductive film is prepared in advance. The substrate is a film of polyethylene terephthalate (PET) coated with a polyurethane on one side, and the film is not coated with a polyaminocarboxylic acid by a double-sided tape or the like. The surface of the ester is adhered to a glass substrate to be fabricated. First, a coating material for forming an ITO conductive film is applied onto a substrate fixed to a glass substrate by a bar coating method, a die coating method, a doctor blade method, or the like, followed by drying. Then, the substrate coated with the coating material for forming an ITO conductive film is peeled off from the glass substrate, and another film such as PET is laminated on the coated surface of the coating material for forming an ITO conductive film in the substrate, and in this state, by rolling. After the pressure is applied under the conditions of a roller pressure of 100 to 2000 kg/cm and a delivery speed of 10 to 50 cm/min, the other film is peeled off. Thereby, an ITO conductive film is formed on the film.

<Evaluation method of ITO conductive film>

Regarding the transparent conductive film obtained as described above, the surface resistance was evaluated as follows. In other words, the measurement points of the transparent conductive film obtained as described above are measured by the Loresta APMCP-T400 manufactured by Mitsubishi Petrochemical Co., Ltd., and the measured value is set as the initial electricity. Resistance value. Thereafter, after storing in a constant temperature and humidity chamber controlled to 85 ° C and a relative humidity of 85% RH for 2,000 hours, the resistance value was measured again at the measurement point set at the initial resistance measurement, and the resistance was measured as a humidification resistance. value. Further, the rate of change was calculated according to the following formula.

Rate of change = [resistance value after humidification / initial resistance value]

[Examples]

Next, an embodiment of the present invention will be described in detail together with a comparative example.

<Example 1>

A solution of 0.1 g of tetramethoxynonane (manufactured by Tama Chemicals Co., Ltd., trade name: methyl n-decanoate) as a surface treatment agent was slowly added dropwise to 39.9 g of ethanol as a dispersion medium. The solution was stirred for 30 minutes. 10 g of the ITO powder obtained by the above method was added to the solution, and dispersed by an ultrasonic homogenizer for 30 minutes to prepare a coating material for forming an ITO conductive film. The concentration of the surface treatment agent was 1% by mass based on 100% by mass of the ITO powder. According to the method for producing a transparent conductive film, the ITO conductive film-forming coating material was formed on a PET film by a bar coating method, and pressure was applied to the film at a roll pressure of 700 kg/cm and a feed rate of 30 cm/min to obtain ITO. Conductive film.

<Example 2>

A solution of 1 g of the same surface treatment agent as in Example 1 was slowly added dropwise to 39 g of methanol as a dispersion medium to prepare a solution. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 10% by mass based on 100% by mass of the ITO powder.

<Example 3>

A solution was prepared by slowly dropping 3 g of the same surface treatment agent as in Example 1 to 37 g of 2-propanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 30% by mass based on 100% by mass of the ITO powder.

<Example 4>

A 3 to 5 polymer of tetramethoxy decane which is an oligomer of phthalic acid ester as a surface treatment agent (manufactured by Tama Chemicals Co., Ltd., commercially available as a product of 39.9 g of 1-butanol as a dispersion medium) Name: M citrate 51) 0.1 g to prepare a solution. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 1% by mass based on 100% by mass of the ITO powder.

<Example 5>

A solution of 1 g of the same surface treatment agent as in Example 4 was slowly added dropwise to 39 g of methanol as a dispersion medium to prepare a solution. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 10% by mass based on 100% by mass of the ITO powder.

<Example 6>

A solution was prepared by slowly dropping 3 g of the same surface treatment agent as in Example 4 to 37 g of ethanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 30% by mass based on 100% by mass of the ITO powder.

<Example 7>

It was prepared by slowly dropping 39.9 g of 1-propanol as a dispersion medium into 0.1 g of tetraethoxysilane (manufactured by Tama Chemicals Co., Ltd., trade name: high purity n-decanoic acid ethyl ester) as a surface treatment agent. Solution. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 1% by mass based on 100% by mass of the ITO powder.

<Example 8>

A solution was prepared by slowly dropping 1 g of the same surface treatment agent as in Example 7 into 39 g of ethanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 10% by mass based on 100% by mass of the ITO powder.

<Example 9>

A solution was prepared by slowly dropping 3 g of the same surface treatment agent as in Example 7 into 37 g of ethanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The table is 100% by mass relative to the ITO powder. The concentration of the surface treatment agent was 30% by mass.

<Example 10>

3 to 5 mer of tetraethoxy decane which is an oligomer of phthalic acid ester as a surface treatment agent (manufactured by Tama Chemicals Co., Ltd., a product of 39.9 g of 1-propanol as a dispersion medium) Name: decanoate 40) 0.1 g to prepare a solution. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 1% by mass based on 100% by mass of the ITO powder.

<Example 11>

A solution was prepared by slowly dropping 1 g of the same surface treatment agent as in Example 10 to 39 g of 2-propanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 10% by mass based on 100% by mass of the ITO powder.

<Example 12>

A solution was prepared by slowly dropping 3 g of the same surface treatment agent as in Example 10 to 37 g of ethanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 30% by mass based on 100% by mass of the ITO powder.

<Example 13>

Slowly drip 39.99g of ethanol as a dispersion medium as a surface A solution of 0.01 g of N-2-(aminoethyl)-3-aminopropyltrimethoxydecane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM603) was prepared to prepare a solution. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 0.1% by mass based on 100% by mass of the ITO powder.

<Example 14>

A solution was prepared by slowly dropping 0.5 g of the same surface treatment agent as in Example 13 to 39.5 g of 2-butanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 5% by mass based on 100% by mass of the ITO powder.

<Example 15>

A solution was prepared by slowly dropping 3 g of the same surface treatment agent as in Example 13 to 37 g of 2-propanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 30% by mass based on 100% by mass of the ITO powder.

<Example 16>

A solution of 3-aminopropyltrimethoxydecane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM903) as a surface treatment agent was slowly added dropwise to 39.99 g of methanol as a dispersion medium to prepare a solution. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 0.1% by mass based on 100% by mass of the ITO powder.

<Example 17>

A solution was prepared by slowly dropping 0.5 g of the same surface treatment agent as in Example 16 to 39.5 g of ethanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 5% by mass based on 100% by mass of the ITO powder.

<Example 18>

A solution was prepared by slowly dropping 3 g of the same surface treatment agent as in Example 16 into 37 g of ethanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 30% by mass based on 100% by mass of the ITO powder.

<Example 19>

To a solution of 39.99 g of ethanol as a dispersion medium, 0.01 g of 3-mercaptopropylmethyldimethoxydecane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM802) as a surface treatment agent was added dropwise. Solution. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 0.1% by mass based on 100% by mass of the ITO powder.

<Example 20>

A solution was prepared by slowly dropping 0.5 g of the same surface treatment agent as in Example 19 to 39.5 g of 1-butanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. 100 mass relative to ITO powder %, the concentration of the surface treatment agent was 5% by mass.

<Example 21>

A solution was prepared by slowly dropping 3 g of the same surface treatment agent as in Example 19 to 37 g of ethanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 30% by mass based on 100% by mass of the ITO powder.

<Example 22>

A solution was prepared by slowly dropping 0.01 g of 3-mercaptopropyltrimethoxydecane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM803) as a surface treatment agent to 39.99 g of ethanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 0.1% by mass based on 100% by mass of the ITO powder.

<Example 23>

A solution was prepared by slowly dropping 0.5 g of the same surface treatment agent as in Example 22 to 39.5 g of ethanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 5% by mass based on 100% by mass of the ITO powder.

<Example 24>

A solution was prepared by slowly dropping 3 g of the same surface treatment agent as in Example 22 to 37 g of ethanol as a dispersion medium. In addition to this, with the embodiment 1 The ITO conductive film was obtained in the same manner. The concentration of the surface treatment agent was 30% by mass based on 100% by mass of the ITO powder.

<Comparative Example 1>

The surface treatment agent was added to 40.0 g of ethanol as a dispersion medium, and 10.0 g of the ITO powder obtained in the above method was added, and the mixture was dispersed by an ultrasonic homogenizer for 30 minutes to obtain a coating material for forming an ITO conductive film. An ITO conductive film was obtained in the same manner as in Example 1 except the above.

<Comparative Example 2>

The product was produced by Shin-Etsu Chemical Co., Ltd., which is a decazane compound described in Patent Document 2, which is a surface treatment agent, which is gradually added dropwise to 39.5 g of ethanol as a dispersion medium. :SZ-31) 0.5 g to prepare a solution. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 5% by mass based on 100% by mass of the ITO powder.

<Comparative Example 3>

A solution of 0.05 g of the same surface treatment agent as in Example 1 was slowly added dropwise to 39.95 g of ethanol as a dispersion medium to prepare a solution. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 0.5% by mass based on 100% by mass of the ITO powder.

<Comparative Example 4>

A solution was prepared by slowly dropping 5 g of the same surface treatment agent as in Example 1 into 35 g of 2-propanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 50% by mass based on 100% by mass of the ITO powder.

<Comparative Example 5>

A solution of 0.05 g of the same surface treatment agent as in Example 4 was slowly added dropwise to 39.95 g of methanol as a dispersion medium to prepare a solution. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 0.5% by mass based on 100% by mass of the ITO powder.

<Comparative Example 6>

A solution was prepared by slowly dropping 5 g of the same surface treatment agent as in Example 4 into 35 g of ethanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 50% by mass based on 100% by mass of the ITO powder.

<Comparative Example 7>

A solution was prepared by slowly dropping 0.05 g of the same surface treatment agent as in Example 7 to 39.95 g of 1-butanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 0.5% by mass based on 100% by mass of the ITO powder.

<Comparative Example 8>

A solution was prepared by slowly dropping 5 g of the same surface treatment agent as in Example 7 into 35 g of ethanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 50% by mass based on 100% by mass of the ITO powder.

<Comparative Example 9>

A solution was prepared by slowly dropping 0.05 g of the same surface treatment agent as in Example 10 to 39.95 g of ethanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 0.5% by mass based on 100% by mass of the ITO powder.

<Comparative Example 10>

A solution was prepared by slowly dropping 5 g of the same surface treatment agent as in Example 10 into 35 g of ethanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 50% by mass based on 100% by mass of the ITO powder.

<Comparative Example 11>

A solution of 0.001 g of the same surface treatment agent as in Example 13 was slowly added dropwise to 39.999 g of 1-butanol as a dispersion medium to prepare a solution. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 0.01% by mass based on 100% by mass of the ITO powder.

<Comparative Example 12>

A solution was prepared by slowly dropping 5 g of the same surface treatment agent as in Example 13 into 35 g of ethanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 50% by mass based on 100% by mass of the ITO powder.

<Comparative Example 13>

A solution of 0.001 g of the same surface treatment agent as in Example 16 was slowly added dropwise to 39.999 g of ethanol as a dispersion medium to prepare a solution. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 0.01% by mass based on 100% by mass of the ITO powder.

<Comparative Example 14>

A solution was prepared by slowly dropping 5 g of the same surface treatment agent as in Example 16 into 35 g of ethanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 50% by mass based on 100% by mass of the ITO powder.

<Comparative Example 15>

A solution of 0.001 g of the same surface treatment agent as in Example 19 was slowly added dropwise to 39.999 g of ethanol as a dispersion medium to prepare a solution. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 0.01% by mass based on 100% by mass of the ITO powder.

<Comparative Example 16>

A solution was prepared by slowly dropping 5 g of the same surface treatment agent as in Example 19 to 35 g of ethanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 50% by mass based on 100% by mass of the ITO powder.

<Comparative Example 17>

A solution of 0.001 g of the same surface treatment agent as in Example 22 was slowly added dropwise to 39.999 g of 1-propanol as a dispersion medium to prepare a solution. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 0.01% by mass based on 100% by mass of the ITO powder.

<Comparative Example 18>

A solution was prepared by slowly dropping 5 g of the same surface treatment agent as in Example 22 into 35 g of ethanol as a dispersion medium. An ITO conductive film was obtained in the same manner as in Example 1 except the above. The concentration of the surface treatment agent was 50% by mass based on 100% by mass of the ITO powder.

<Comparative Testing and Evaluation>

With respect to the ITO conductive films obtained in Examples 1 to 24 and Comparative Examples 1 to 18, the initial resistance value of each film and the resistance value after humidification were measured according to the above evaluation method. Further, the rate of change was obtained by dividing the resistance value after humidification by the initial resistance value. The results are shown in Tables 1 and 2. In addition, in Tables 1 and 2, the "concentration" indicates the mass % of the surface treatment agent with respect to 100 mass % of ITO powder.

As can be seen from Tables 1 and 2, in Comparative Example 1 in which no surface treatment agent was added, the surface treatment agent of Patent Document 2 was used. Comparative Example 2, and the ITO conductive film obtained in Comparative Examples 3, 5, 7, 9, 11, 13, 15, and 17 in which the blending ratio of the surface treating agent was less than the lower limit of the specific range, from the initial resistance value to the addition The rate of change of the resistance value after wet is as large as 28 times or more. In addition, in the ITO conductive films obtained in Comparative Examples 4, 6, 8, 10, 12, 14, 16, and 18 in which the blending ratio of the surface treatment agent exceeded the upper limit of the specific range, the initial resistance values were as high as 2800 Ω. /□ Above. On the other hand, in the ITO conductive films obtained in Examples 1 to 24, the rate of change from the initial resistance value to the resistance value after humidification was as small as 20 times or less, and the initial resistance values were all as low as 930 Ω/□ or less. According to the coating materials for forming an ITO conductive film of Examples 1 to 24, it is understood that the initial resistance value is low, and the increase in the resistance value can be sufficiently suppressed even under high temperature and high humidity.

10‧‧‧Multicrystalline ITO particles

11‧‧‧ rod center nucleus

12‧‧‧ rods

Claims (4)

A coating material for forming an ITO conductive film, comprising: an ITO powder; a dispersion medium of the ITO powder; and a coating material for forming an ITO conductive film with a surface treatment agent of the ITO powder, wherein the ITO particles are in a rod-shaped central core a plurality of rod-shaped bodies shorter than the central core are integrally formed as an aggregate of polycrystalline ITO particles which are formed in the same direction as the longitudinal direction of the rod-shaped central core and surround the rod-shaped central core, the dispersion medium In the alcohol-based solution, the surface treatment agent is a phthalic acid ester having an alkyl group having 2 or less carbon atoms, or the surface treatment agent is a decane coupling agent having an amine group or a fluorenyl group at a terminal group, and is 100 mass with respect to the ITO powder described above. %, the phthalic acid ester is contained in an amount of 1 to 30% by mass, or the decane coupling agent is contained in an amount of 0.1 to 30% by mass based on 100% by mass of the ITO powder. The coating material for forming an ITO conductive film according to claim 1, wherein the phthalic acid ester is tetramethoxy decane having an alkyl group having 1 carbon atom or tetraethoxy decane having an alkyl group having 2 carbon atoms. The coating material for forming an ITO conductive film according to claim 1, wherein the decane coupling agent is N-2-(aminoethyl)-3-aminopropyltrimethoxydecane, 3-aminopropyltrimethoxydecane, 3- Methyl propyl dimethoxy decane or 3-mercaptopropyl trimethoxy decane. A method of forming an ITO conductive film by using the coating material according to any one of claims 1 to 3 to form an ITO conductive film.