JP5991067B2 - Coating liquid for solvent-resistant transparent conductive film and solvent-resistant transparent conductive film comprising the same - Google Patents

Description

  The present invention relates to a coating liquid suitable as a dispersion for a transparent conductive film and a transparent conductive film comprising the same, and more specifically, crystalline tin-containing indium oxide fine particles having excellent dispersibility in a dispersion solvent. A coating solution for a specific solvent-resistant transparent conductive film capable of forming a solvent-resistant transparent conductive film having resistance to the dispersion solvent from the aggregation of the fine particles after coating, and The present invention relates to a solvent-resistant transparent conductive film excellent in electrical characteristics and optical characteristics.

  In an electronic device such as a personal digital assistant (PDA), a notebook PC, an OA device, a medical device, or a car navigation system, a touch panel having an input means on these displays is widely used.

  As a transparent conductive film used for such a touch panel, indium oxide containing tin, which is used for transparent electrodes such as liquid crystal displays, has been widely used so far because it has excellent transparency and electrical conductivity. ing.

  However, since indium oxide containing tin is generally deposited by sputtering, the process is complicated, the use efficiency of the material is low, and an expensive vacuum film forming apparatus is required. , Etc. are pointed out.

  On the other hand, a coating-type material that does not require a vacuum process and can form a film with a large area or a complicated shape has attracted attention. So far, a fine particle dispersion of noble metal or metal oxide has been applied. A transparent conductive film obtained in this manner has been reported.

  For those using noble metal fine particles, specifically, a conductive liquid in which noble metal fine particles such as gold, silver and copper are uniformly dispersed in the liquid is applied on the display surface of the display device and dried. The transparent noble metal thin film is formed, and a transparent layer having a refractive index different from that of the transparent noble metal thin film is laminated on the upper layer and / or the lower layer of the transparent noble metal thin film for electromagnetic wave shielding, antistatic, antireflection, and the like. For example, a transparent conductive film excellent in electromagnetic wave shielding effect and antireflection effect comprising a conductive layer made of noble metal fine particles containing at least silver within an average particle diameter of 2 to 200 nm and a transparent layer having a different refractive index (for example, a patent) Reference 1)) has been proposed.

  However, in the method proposed in Patent Document 1, although an electromagnetic wave shielding effect can be expected, depending on the light transmission spectrum of silver, absorption occurs in transmitted light of 400 to 500 nm, the conductive film is colored yellow, and the transmission image The hue of the film changes unnaturally, and because the light transmittance of the film is low, unevenness in the transmitted color due to the film thickness distribution is easily noticeable and the productivity is deteriorated. In a salt fog environment, the surface resistivity of the conductive film increases and electromagnetic waves Since the shielding effect is lowered, there is a problem that durability is lowered in a place that is easily affected by salt fog such as a coast.

  In addition, in the case of using metal oxide fine particles, a method of producing a transparent conductive film by applying a coating solution in which fine particles of tin-containing indium oxide are dissolved or dispersed in water or an organic solvent on a substrate, and drying and baking. Has been proposed. For example, a sol composition containing particles of indium / tin composite oxide is used as a coating solution, and this coating solution is applied onto a substrate, dried and fired to form a film made of conductive indium oxide particles. A method (for example, refer to Patent Document 2) is proposed.

  However, the indium compound contained in the coating solution is usually a so-called indium oxide precursor such as an inorganic or organic indium salt, and high conductivity can be obtained simply by applying such a dispersion on a substrate and then drying it. A crystalline indium oxide coating film exhibiting properties and solvent resistance can not be obtained, and the coating film after coating on the substrate is baked at a high temperature of 400 ° C. or higher to thermally decompose the indium salt. Only when indium oxide is crystallized, a highly conductive indium oxide film is formed. Also in the method proposed in Patent Document 2, the composite oxide fine particles in the indium-tin composite oxide sol are amorphous oxides, and the amorphous oxides are fired at a high temperature. In this embodiment, the conductive film is formed through a process of baking at 500 ° C. However, when the coating is heated at a high temperature of about 500 ° C., the base material is damaged when the base material is a plastic base material, and when the base material is a glass base material, the base material is damaged. There was a case where a problem such as distortion or cracking occurred.

  Therefore, it is expected that crystalline metal oxide fine particles are used as a coating film in order to develop high conductivity only by coating without requiring a baking process at a high temperature.

  Then, a method of obtaining crystalline metal oxide fine particles without the need for sintering at a high temperature of 400 ° C. or higher (see, for example, Patent Document 3 and Patent Document 4), heating at 350 ° C. or lower, and crystal at normal pressure Proposed are methods for obtaining conductive ITO fine particles (see, for example, Patent Documents 5, 6, and 7), synthesis of tin-containing indium oxide fine particles coordinated with oleylamine (for example, see Non-Patent Document 1), and the like.

Japanese Patent Application Laid-Open No. 08-077782 (for example, refer to the claims) Japanese Patent Laid-Open No. 59-223229 (for example, refer to the claims) Japanese Unexamined Patent Application Publication No. 2004-123418 (see, for example, the claims) Japanese Patent Laying-Open No. 2006-096636 (for example, refer to the claims) Japanese Patent Laying-Open No. 2007-269617 (see, for example, the claims) Japanese Patent Laying-Open No. 2009-084122 (for example, refer to the claims) Japanese Patent Laying-Open No. 2011-126746 (for example, refer to the claims)

J. et al. Am. Chem. Soc. 2009, 131, 17736-17737

  However, in the methods proposed in Patent Documents 3 and 4, a treatment step under a pressurized condition is essential, and it is difficult to say that the method is suitable for a mass production process. It had a problem in terms of sex. In addition, the ITO fine particles obtained by the methods proposed in Patent Documents 5 to 7 have high dispersibility, and since the contact area between the particles of the particle powder obtained after drying is small, sufficient conductivity as a transparent conductive film is obtained. In addition to having high solvent dispersibility, the particulate powder after drying is easily redispersed in the dispersion medium and has a problem in solvent resistance as a transparent conductive film. It was. Furthermore, the tin-containing indium oxide fine particles coordinated with oleylamine proposed in Non-Patent Document 1 have not been mentioned at all about conductivity and solvent resistance.

  The present invention has been made in view of the above facts, and is a dispersion containing crystalline tin-containing indium oxide fine particles having excellent dispersibility in a dispersion solvent. After coating, the dispersion is redispersed in the dispersion solvent by particle aggregation. An object of the present invention is to provide a solvent-resistant transparent conductive film coating liquid capable of forming a difficult and stable transparent conductive film, and a solvent-resistant transparent conductive film using the coating liquid.

  As a result of diligent investigations to solve the above problems, the inventors of the present invention used a transparent conductive film for dispersing a crystalline tin-containing indium oxide fine particle dispersion containing specific crystalline tin-containing indium oxide fine particles with respect to a dispersion solvent. As a coating liquid for coating, it has been found that a stable transparent conductive film that is difficult to re-disperse in a dispersion solvent can be formed by coating, and the present invention has been completed.

That is, the present invention is a dispersion containing 0.1 to 100 parts by weight of crystalline tin-containing indium oxide fine particles having at least the following characteristics (a) to (d) with respect to 100 parts by weight of the dispersion solvent. The present invention relates to a solvent-resistant transparent conductive film coating liquid and a solvent-resistant transparent conductive film comprising the same.
(A) a cubic bixbite structure;
(B) Tin / indium (molar ratio) measured by an inductively coupled plasma optical emission spectrometer (ICP) is in the range of 5/95 to 40/60.
(C) The average particle diameter measured by a transmission electron microscope is in the range of 5 to 20 nm.
(D) Coordinates 1 to 10% by weight of an amine ligand having 6 to 24 carbon atoms.

  Hereinafter, the present invention will be described in detail.

  The solvent-resistant transparent conductive film coating liquid of the present invention comprises a dispersion obtained by dispersing crystalline tin-containing indium oxide fine particles satisfying the above-described characteristics (a) to (d) in a dispersion solvent. Here, by using the crystalline tin-containing indium oxide fine particles satisfying the characteristics of (a) to (d) at the same time, the coating solution for a solvent-resistant transparent conductive film of the present invention has the crystalline tin-containing indium oxide. It becomes excellent in dispersion stability of fine particles, and the obtained transparent conductive film has excellent conductivity and solvent resistance.

  The crystalline tin-containing indium oxide fine particles constituting the solvent-resistant transparent conductive film coating liquid of the present invention have (a) a cubic bixbite structure, and by having a cubic bixbite structure, The solvent-resistant transparent conductive film obtained from the coating solution for solvent-resistant transparent conductive film of the present invention is excellent in conductivity and solvent resistance.

  The cubic bixbite structure can be confirmed by measuring an X-ray diffraction pattern. For example, a tin-containing indium oxide fine particle powder is prepared from a tin-containing indium oxide fine particle dispersion, It can be confirmed by encapsulating and measuring in the range of 5 to 70 ° with an X-ray diffraction measurement device (for example, (trade name) Spectris X'pert PRO MPD manufactured by PANalytical). When the crystalline tin-containing indium fine particles are crystals having a cubic bixbite structure, the X-ray diffraction pattern is 2θ = 20-21 °, (211) plane diffraction, 2θ = 30-31 °. Diffraction of (222) plane, diffraction of (400) plane at 2θ = 35 to 36 °, diffraction of (440) plane at 2θ = 50 to 51 °, diffraction of (622) plane at 2θ = 60 to 61 °, Observed respectively.

  Further, the crystalline tin-containing indium oxide fine particles constituting the solvent-resistant transparent conductive film coating liquid of the present invention are measured by (b) an inductively coupled plasma emission spectrometer (hereinafter sometimes referred to as ICP). Is a crystalline tin-containing indium oxide in which tin / indium, which is the ratio (molar ratio) of tin to indium, is in the range of 5/95 to 40/60, and is a solvent-resistant transparent conductive material that exhibits better conductivity In order to obtain a film, tin / indium is preferably 10/90 to 30/70, and more preferably 10/90 to 20/80. Here, when the ratio of tin is lower than tin / indium = 5/95, the carrier amount supplied by tin is insufficient, so that a sufficient band gap cannot be formed, and the coating film becomes a transparent conductive film. Does not exhibit sufficient conductivity. On the other hand, when the ratio of tin exceeds tin / indium = 40/60, excessive tin forms an oxide that does not contribute to carrier generation, and this becomes a neutral scattering center. The film does not exhibit sufficient conductivity as a film. In addition, the content of tin in the crystalline tin-containing indium oxide fine particles can be arbitrarily selected, for example, by adjusting the charging ratio of indium and tin when preparing the crystalline tin-containing indium oxide fine particles described later. Is possible.

  For measurement by ICP, for example, a tin-containing indium oxide fine particle powder is prepared from a tin-containing indium oxide fine particle dispersion, and the powder is decomposed by heating and acid treatment. It can be measured using an analyzer such as an inductively coupled argon plasma emission spectrometer (Vista-PRO axial specification) manufactured by Seiko Instruments Inc.

  Further, the crystalline tin-containing indium oxide fine particles constituting the solvent-resistant transparent conductive film coating liquid of the present invention are (c) average particles measured by a transmission electron microscope (hereinafter sometimes referred to as TEM). The diameter is in the range of 5 to 20 nm. Here, when the average particle diameter of the crystalline tin-containing indium oxide fine particles is less than 5 nm, since the particle diameter of the crystalline tin-containing indium oxide fine particles is too small, sufficient conductivity is obtained when the transparent conductive film is formed. The transparent conductive film which has is not obtained. On the other hand, when the average particle diameter exceeds 20 nm, since the particle diameter of the crystalline tin-containing indium oxide fine particles is too large, light is scattered when a dispersion solution or a coating film is formed, and light is transmitted in the visible light region. The rate will be worse. Further, the crystalline tin-containing indium oxide fine particles are preferably spherical fine particles because they can form a solvent-resistant transparent conductive film that is more excellent in transparency and conductivity, and are particularly observed by TEM. The average value of the aspect ratio is preferably in the range of 0.7 to 1.3.

  For the measurement of the average particle diameter of the crystalline tin-containing indium oxide fine particles, for example, a low-concentration fine particle dispersion having a concentration of 0.01% or less prepared by dispersing the crystalline tin-containing indium oxide fine particles in an organic solvent is prepared. Then, it can be measured by a method in which this is dropped on a carbon-coated copper mesh with a collodion film stretched to volatilize the solvent and observed with a transmission microscope. The average particle diameter of the crystalline tin-containing indium oxide fine particles is measured by taking a photograph of an image observed at a magnification of 200,000 times, measuring the particle diameters of 300 or more particles, and averaging them. The average particle diameter can be determined.

  Further, the crystalline tin-containing indium oxide fine particles constituting the solvent-resistant transparent conductive film coating liquid of the present invention are coordinated with (d) 1 to 10% by weight of an amine ligand having 6 to 24 carbon atoms. It will be. Since the crystalline tin-containing indium oxide fine particles have crystallinity, they do not require a sintering step at a high temperature of 400 ° C. or higher when forming a transparent conductive film, and by coating or coating and heating at 200 ° C. or lower. A solvent-resistant transparent conductive film can be produced. In addition, by coordinating an amine ligand having 6 to 24 carbon atoms, the amine ligand solvates with the dispersion solvent, so that no special dispersant or special operation is required. Only by adding the crystalline tin-containing indium oxide fine particles to the dispersion solvent, a dispersion having excellent dispersion stability and a coating solution for a solvent-resistant transparent conductive film can be obtained. On the other hand, by coordinating the amine ligand having 6 to 24 carbon atoms that contributes to dispersibility in the dispersion solvent in a specific range of 1 to 10% by weight, the crystalline tin-containing indium oxide fine particles are obtained. In the dispersion liquid or coating liquid stage, it has an appropriate dispersion stability of fine particles, and once dried by coating, the fine particles are not dispersed again by the dispersion solvent. However, a stable agglomerated film of crystalline tin-containing indium oxide fine particles is formed, and a solvent-resistant transparent conductive film can be provided.

  Here, in the case of an amine ligand having less than 6 carbon atoms, the crystalline tin-containing indium oxide fine particles have reduced dispersion stability in the dispersion solvent, and the resulting coating solution has poor dispersion stability. When stored, the crystalline tin-containing indium oxide fine particles are likely to aggregate. On the other hand, when it is an amine ligand having more than 24 carbon atoms, the distance between the particles of crystalline tin-containing indium oxide fine particles becomes long when the coating film is formed, and the conductive performance is lowered. become unable. In addition, when the coordination amount of the amine ligand having 6 to 24 carbon atoms is less than 1% by weight, the crystalline tin-containing indium oxide fine particles can be obtained by reducing the dispersion stability in the dispersion solvent. The liquid is inferior in dispersion stability and tends to cause aggregation of the crystalline tin-containing indium oxide fine particles during storage. On the other hand, when the coordination amount of the amine ligand having 6 to 24 carbon atoms exceeds 10% by weight, the aggregation stability of the crystalline tin-containing indium oxide fine particles when the coating film is formed is inferior, and the amount of It will be inferior in stability.

The amine ligand having 6 to 24 carbon atoms may be either a monodentate ligand or a polydentate ligand as long as it is an amine ligand having 6 to 24 carbon atoms capable of coordination with indium and tin. Can be used, and examples thereof include those having a structure represented by the following general formula (1).
R (NH ₂ ) _n (1)
(Here, R represents an alkyl group having 6 to 24 carbon atoms or an aryl group, and n represents a natural number.)
Specific examples of the compound constituting the amine ligand having 6 to 24 carbon atoms include hexylamine, octylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, and hexadecyl. Amine, heptadecylamine, stearylamine, hebenylamine, nonadecylamine, oleylamine, hexamethylenediamine, 4-methylaniline and the like can be mentioned. Among them, an amine ligand having a chain structure is preferable in order to improve the dispersion stability of the crystalline tin-containing indium oxide fine particles and to exhibit high conductivity, and particularly has 10 to 22 carbon atoms. An amine ligand having a chain structure is preferable, and specific examples of the compound constituting the ligand include stearylamine, hebenylamine, decylamine, dodecylamine, tetradecylamine, and oleylamine.

  As a method for measuring the coordination amount of the amine ligand in the crystalline tin-containing indium oxide fine particles, any method can be used as long as the content of the amine ligand in the fine particles can be measured. For example, a crystalline tin-containing indium oxide fine particle dispersion is filtered through a 0.5 μm filter, and then the dispersion is dried to solidify a crystalline tin-containing indium oxide fine particle powder. Crystalline tin-containing indium oxide fine particles up to 500 ° C. in a nitrogen atmosphere by a method for calculating the coordination amount of an amine ligand and a differential thermothermal gravimetric simultaneous measurement apparatus (hereinafter sometimes referred to as TG / DTA). Examples include a method of heating and measuring the weight change as the amine ligand content.

  Hereinafter, as a specific method for measuring the amine ligand content, a method for measuring the amine ligand content using a differential thermothermal gravimetric simultaneous measurement apparatus (TG / DTA) is shown.

  A crystalline tin-containing indium oxide fine particle dispersion is filtered through a 0.5 μm filter, and then dried to prepare a crystalline tin-containing indium oxide fine particle powder. TG / DTA (manufactured by SII Nanotechnology, Inc. Name) EXSTAR TG / DTA6200), held in nitrogen atmosphere at 100 ° C. for 60 minutes, then raised to 500 ° C. at 10 ° C./minute, then held at 500 ° C. for 180 minutes, in the range of 100 ° C. to 500 ° C. The decrease in weight is defined as the amount of amine ligand.

  There is no restriction | limiting in particular in the dispersion solvent which comprises the coating liquid for solvent resistant transparent conductive films of this invention, Dispersing the crystalline tin containing indium oxide fine particle which satisfies the characteristic shown to said (a)-(d) may be disperse | distributed. Any dispersion solvent can be used if possible, and a general organic solvent can also be used.

  Examples of the dispersion solvent include aromatic hydrocarbons such as toluene, xylene, mesitylene, benzene, dichlorobenzene, and nitrobenzene; aliphatic hydrocarbons such as n-heptane, n-hexane, n-octane, cyclohexane, and decahydronaphthalene. Ketones such as acetone, methyl ethyl ketone, diethyl ketone, acetyl acetone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, N-methylpyrrolidone; amides such as formamide, N, N-dimethylformamide, N, N-dimethylacetamide; Ethers such as diethyl ether, tetrahydrofuran, dioxane, methoxyethanol, ethoxyethanol; chlorinated aliphatic hydrocarbons such as dichloromethane, chloroform, 1,2-dichloroethane; methano Alcohol, ethanol, isopropyl alcohol, and the like; ethyl acetate, butyl acetate, acetate esters such as amyl acetate, and the like. Since it becomes a coating liquid for conductive films, n-hexane, cyclohexane, chloroform, diethyl ether, toluene, benzene, o-dichlorobenzene, p-dichlorobenzene, tetrahydrofuran, and decahydronaphthalene are preferable, and n-hexane, Cyclohexane, chloroform, toluene and decane are preferred. Further, the dispersion solvent may be a combination of several of these.

  The coating solution for a solvent-resistant transparent conductive film of the present invention is a dispersion liquid containing at least 0.1 to 100 parts by weight of the crystalline tin-containing indium oxide fine particles with respect to 100 parts by weight of the dispersion solvent. Since the dispersion stability of the crystalline tin-containing indium oxide fine particles is excellent and the film resistance of the solvent-resistant transparent conductive film is excellent, 0.1 to 50 parts by weight of the crystalline tin-containing indium oxide fine particles, particularly It is preferable that it contains 0.1 to 30 parts by weight, and further 0.1 to 10 parts by weight. Here, when the crystalline tin-containing indium oxide fine particles in the coating liquid is less than 0.1 parts by weight, the cohesiveness between the crystalline tin-containing indium oxide fine particles is reduced when forming a coating film, and the coating film Since the distance between the fine particles in the inside increases, it becomes difficult to obtain a conductive film having sufficient conductivity. On the other hand, when the crystalline tin-containing indium oxide fine particles exceed 100 parts by weight, the fine particles in the coating liquid become unstable and the dispersion stability is poor.

  Since the coating solution for solvent-resistant transparent conductive film of the present invention can provide a solvent-resistant transparent conductive film particularly excellent in transparency, the light transmittance is 90% or more, particularly 92% or more. Are preferred. The haze is preferably 2% or less, particularly 1% or less. The light transmittance at this time can be measured according to JIS K 7361-1 using a liquid cell having a thickness of 10 mm, for example, with a haze meter (trade name NDH-5000) manufactured by Nippon Denshoku Industries Co., Ltd. is there. Further, haze can be measured in accordance with JIS K 7136 using a liquid cell having a thickness of 10 mm with a haze meter (trade name NDH-5000) manufactured by Nippon Denshoku Industries Co., Ltd.

  Although the specific example of the preferable manufacturing method of the coating liquid for solvent-resistant transparent conductive films of this invention is shown below, these illustrations do not limit this invention.

  The crystalline tin-containing indium oxide fine particles may be obtained by any method as long as they are crystalline tin-containing indium oxide fine particles satisfying the above (a) to (d), for example, indium carboxylate, It can be obtained by heating a mixture of tin carboxylate and an amine ligand having 6 to 24 carbon atoms to 220 ° C or higher. Further, indium acid indium typified by indium sulfate, indium nitrate or the like can be used instead of indium carboxylate.

  The indium carboxylate contains oxygen for forming crystalline tin-containing indium oxide fine particles. The carboxylate added to indium in indium carboxylate is preferably a carboxylate having 1 to 20 carbon atoms, and particularly preferably a saturated aliphatic carboxylate, an unsaturated carboxylate, or an aromatic carboxylate.

  Specific examples of the indium carboxylate include indium formate, indium acetate, indium propionate, indium butyrate, indium valerate, indium caproate, indium enanthate, indium caprylate, indium pelargonate, indium caprate, lauric acid. Saturated aliphatic indium carboxylates such as indium oxide, indium myristate, indium palmitate, indium margarate, indium stearate, indium oleate and indium 2-ethylhexanoate; unsaturated indium such as indium oleate and indium linoleate Carboxylate; Indium aromatic carboxylates such as indium tribenzoate and indium phthalate;

  The tin carboxylate also contains oxygen for forming tin-containing indium oxide fine particles, like the above-mentioned indium carboxylate. The carboxylate added to tin in the tin carboxylate is preferably a carboxylate having 1 to 20 carbon atoms, and particularly preferably a saturated aliphatic carboxylate, an unsaturated carboxylate, or an aromatic carboxylate.

  Specific examples of the tin carboxylate include tin formate, tin acetate, tin propionate, tin butyrate, tin valerate, tin caproate, tin enanthate, tin caprylate, tin pelargonate, tin caprate, lauric acid Saturated aliphatic tin carboxylates such as tin, tin myristate, tin palmitate, tin margarate, tin stearate, tin oleate, tin 2-ethylhexanoate; unsaturated indium carboxyl such as tin oleate and tin linoleate Rate; tin aromatic carboxylic acid such as tin benzoate and tin phthalate; and the like.

  As the amine ligand having 6 to 24 carbon atoms, the same ligands as described above can be used.

  The ratio of indium carboxylate and tin carboxylate in producing the crystalline tin-containing indium oxide fine particles is arbitrary, and in particular, since the crystalline tin-containing indium oxide fine particles having excellent conductivity are obtained, indium carboxylate / It is preferable to carry out the reaction with tin carboxylate (molar ratio) = 95/5 to 60/40. Further, the amount of the amine ligand having 6 to 24 carbon atoms is sufficient if the amount capable of substituting the carboxylate in indium carboxylate and tin carboxylate is used, but in order to advance the reaction efficiently, indium It is desirable to use an excess amount of amine ligand rather than the sum of the number of moles of carboxylate and tin carboxylate, for example, the sum of the number of moles of indium carboxylate and tin carboxylate used in the reaction and 6 to 24 carbon atoms. The ratio of the number of moles of the amine ligand is in the range of (sum of moles of indium carboxylate and tin carboxylate) / (amine ligand having 6 to 24 carbon atoms) = 1/1 to 1/1000. It is preferable that the range is 1/1 to 1/100.

  Then, by heating and reacting indium carboxylate, tin carboxylate, and an amine ligand having 6 to 24 carbon atoms to a temperature of 220 ° C. or higher, the crystalline tin-containing indium oxide fine particles can be produced. Furthermore, it is preferable that it is 220 to 280 degreeC. In that case, it is also possible to use a solvent, and the solvent preferably has a boiling point of 220 ° C. or higher. For example, 1-octadecene, butyl benzoate, 1-dodecanol, 1-tridecanol, 1-tetradecanol, 1-pentadecanol, diethylene glycol, triethylene glycol, tetraethylene glycol, di-n-octyl ether, diphenyl ether, ethylene glycol monophenyl ether, triethylene glycol monomethyl ether, diethylene glycol dibutyl ether, triethylene glycol Examples thereof include butyl methyl ether and tetraethylene glycol dimethyl ether.

  Further, when producing the crystalline tin-containing indium oxide fine particles, an organic acid may be added for the purpose of controlling the reaction rate. Examples of the organic acid include formic acid, acetic acid, propionic acid, butyric acid, and pentanoic acid. , Isovaleric acid, pivalic acid, 3-methylbutanoic acid, heptanoic acid, 2-methylpentanoic acid, 3-methylpentanoic acid, 4-methylpentanoic acid, 2,2-dimethylbutanoic acid, 2,3-dimethylbutanoic acid, 2-ethylbutanoic acid, hexanoic acid, 2,2-dimethylpentanoic acid, n-octanoic acid, 2-ethylhexanoic acid, nonanoic acid, decanoic acid, lauric acid, tetradecanoic acid, pentadecylic acid, hexadecanoic acid, heptadecanoic acid, stearic acid Oleic acid, icosanoic acid, etc. can be used, and the amount used can be arbitrarily set according to the purpose. .

  The atmosphere during the reaction is preferably under anoxic conditions, and is preferably under reduced pressure in a nitrogen stream.

  Then, by refining the obtained crystalline tin-containing indium oxide fine particles, for example, by centrifugation, a coating for a solvent-resistant transparent conductive film that can give a transparent conductive film particularly excellent in the balance between conductivity and solvent resistance Can be liquid. In this case, centrifugation is performed by separating the obtained reaction liquid or dispersion into fine particles and supernatant using a centrifuge, adding the dispersion solvent after removing the supernatant, and repeating the centrifugation, A method for cleaning fine particles will be described. And if it is the conditions which can isolate | separate microparticles | fine-particles and a supernatant liquid at the time of centrifugation, there will be no restriction | limiting in particular in the conditions of a centrifuge. Further, the dispersion solvent to be used is not particularly limited as long as it is a dispersion medium in which fine particles are sufficiently dispersed and settled.

  And it becomes possible to separate crystalline tin-containing indium oxide fine particles from unreacted raw materials, reaction byproducts, etc. by refining and centrifuge refining, and especially transparent with excellent balance between conductivity and solvent resistance. It becomes a solvent-resistant coating liquid for transparent conductive film that can provide a conductive film. Among them, since it becomes a coating solution for a solvent-resistant transparent conductive film that can give a transparent conductive film particularly excellent in solvent resistance, an unreacted amine ligand having 6 to 24 carbon atoms, that is, 6 to 24 carbon atoms. It is preferable to separate and purify the free amine ligand of 10000 ppm or less based on the weight of the crystalline tin-containing indium oxide fine particles. As the centrifugation purification conditions at that time, for example, centrifugation is preferably repeated 3 times or more, preferably 4 times or more, and since particularly high free amine ligand separation can be realized, crystalline tin-containing oxidation It is preferable to use a combination of a solvent for precipitating indium fine particles (hereinafter referred to as a precipitation solvent) and the dispersion solvent described above.

  As the precipitation solvent, any solvent that agglomerates and precipitates crystalline tin-containing indium oxide fine particles can be used, and an alcohol solvent is particularly preferable. For example, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-methyl-1-propanol, 2-butanol, 2-methyl-2-butanol, 1-pentanol, 2-pentanol, 3- Pentanol, cyclopentanol, 1-hexanol, 2-hexanol, 3-hexanol, cyclohexanol, 2-ethyl-1-butanol, 3,3′-dimethyl-1-butanol, 3,3′-dimethyl-2- Butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl -1-pentanol, 2-methyl-2-pentanol, 1,4-butanediol, 1,3-butanediol, Examples thereof include methanol, ethanol, crotyl alcohol, etc. Methanol, ethanol, 1-propanol, 2-propanol, cyclohexanol, and benzyl alcohol are preferably used from the viewpoint of precipitation characteristics and practicality of fine particles. -Propanol is particularly preferred.

  As the dispersion solvent, the same solvents as described above can be used. By repeating purification and centrifugation, the reaction solvent and the precipitation solvent can be replaced with the dispersion solvent. It becomes possible to set it as the coating liquid for solvent-based transparent conductive films.

  In addition, the amount of free amine ligand that may be contained in the solvent-resistant conductive film coating solution of the present invention can be measured by a chromatography method typified by gas chromatography or liquid chromatography. Is possible.

  The coating solution for solvent-resistant transparent conductive film of the present invention is, for example, coated on a substrate and dried, preferably dried at 200 ° C. or less, so that the transparency, conductivity and solvent resistance are excellent. A conductive film can be formed. As the coating method at that time, for example, spin coating method, drop coating method, roll coating method, spray method, bar coating method, dipping method, meniscus coating method, doctor blade method, screen printing method, T-die method, lip coater Any known method such as a method or a roll coating method can be used. The drying conditions after coating are arbitrary and may be selected depending on the dispersion solvent constituting the solvent-resistant transparent conductive film coating solution. Among them, crystalline tin-containing indium oxide fine particles are packed more densely in the coating film. Drying, in the range of 10 to 200 ° C., more preferably in the range of 20 to 180 ° C., because the stability of the coated film after drying is improved and the variation in sheet resistance due to temperature and humidity is reduced. It is preferable to do. The drying atmosphere is not particularly limited, such as in air, nitrogen atmosphere, or reduced pressure.

  Moreover, there is no restriction | limiting in particular also about a base material, For example, polymer base materials, such as inorganic base materials, such as glass type; polyethylene terephthalate, a polyimide, a polycarbonate, a polyethylene naphthalate, etc. can be used. These base materials may be subjected to a surface treatment in order to improve the adhesion to the solvent-resistant transparent conductive film. Examples of the surface treatment agent include a silane coupling agent and an organic metal. . Examples of the silane coupling agent include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, tris (2-methoxyethoxy) vinylsilane, γ-glycidoxypropyltrimethoxysilane, γ- (methacryloxypropyl) tri Examples include methoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and the like. Examples thereof include organic titanium, organic aluminum, and organic zirconium.

  The thickness of the solvent-resistant transparent conductive film of the present invention is arbitrary as long as the object of the present invention is not impaired, and among them, the thickness becomes 0.001 to 5 μm because the conductive film is particularly excellent in balance between transparency and conductivity. In particular, 0.01 to 2 μm is preferable, and 0.02 to 1 μm is more preferable. Moreover, since it has sufficient transparency as a transparent conductive material, the light transmittance measured according to JIS K 7361-1 is preferably 80% or more, and particularly preferably 85% or more. Further, the haze measured in accordance with JIS K 7136 is preferably 5% or less, and particularly preferably 3% or less.

The solvent-resistant transparent conductive film coating liquid of the present invention contains crystalline tin-containing indium oxide fine particles, and the crystalline tin-containing indium oxide fine particles have crystallinity. It is possible to form a conductive film that exhibits high conductivity simply by doing so. On the other hand, many of the metal oxide fine particles reported so far are amorphous oxides, and have to be crystallized by firing at a high temperature of 300 ° C. or higher. Since the solvent-resistant transparent conductive film comprising the coating solution for solvent-resistant transparent conductive film of the present invention is composed of fine particles having crystallinity, it is highly conductive only by drying after coating (for example, at a low temperature of 200 ° C. or lower). It has the characteristics to express sex. The sheet resistance of the obtained solvent-resistant transparent conductive film is preferably 10 ⁵ Ω / □ or less, particularly preferably 5 × 10 ⁴ Ω / □ or less, and more preferably 10 ⁴ Ω / □ or less. Preferably there is.

  Further, the coating solution for solvent-resistant transparent conductive film of the present invention has the property that once the dispersion solvent in the dispersion is volatilized, the crystalline tin-containing indium oxide fine particles are aggregated, and the coating / drying By doing so, it is possible to form a coating film that is not redispersed in the dispersion medium, that is, a transparent conductive film having high solvent resistance. In addition, since the aggregate which consists of microparticles | fine-particles produced in this case is what aggregated about 1-30 particles, it does not impair the external appearance of a coating film.

  And even if the solvent-resistant transparent conductive film of the present invention is immersed again in the same dispersion solvent, whitening of the coating film and redispersion of the fine particles hardly occur, and the dispersion degree of the coating film with respect to the dispersion solvent is 10% by weight. It is preferably 5% by weight or less, more preferably 1% by weight or less. And the dispersion degree with respect to the dispersion solvent of the coating film in this case is, for example, a temperature at which the coating film can be removed after immersing the coating film in an organic solvent used as a dispersion solvent before film formation for 3 hours. By drying the coating film and measuring the weight change before and after immersion, the weight re-dispersed in the dispersion solvent can be calculated, and the degree of dispersion of the coating film can be calculated.

  The solvent-resistant transparent conductive film coating liquid of the present invention has higher conductivity, higher transparency, and solvent resistance than the sputtering method, which is a transparent conductive film forming method by a conventional vacuum process, at a simpler and lower cost. A transparent conductive film can be provided. In addition, since a metal oxide is used, it is possible to provide a transparent conductive film having a light transmittance higher than that of a coating film using a conventional noble metal and having less uneven transmission color.

  According to the present invention, it is possible to form a transparent conductive film excellent in transparency, conductivity and solvent resistance more easily by a simple method of coating, and its industrial value is extremely high.

  EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

<Purification of crystalline tin-containing indium oxide fine particles>
The obtained crude crystalline tin-containing indium oxide fine particle dispersion was purified by repeating centrifugal separation using a centrifuge ((trade name) H-201F, manufactured by Kokusan Co., Ltd.).

<Appearance observation of crystalline tin-containing indium oxide fine particles>
The appearance of the crystalline tin-containing indium oxide fine particles was observed with a transmission electron microscope (TEM). Prepare a fine particle dispersion with a concentration of 0.01% or less in which the fine particles are dispersed in an organic solvent. The fine particle dispersion is dropped on a carbon-coated copper mesh with a collodion film, and the solvent is volatilized. This sample is observed with a transmission microscope. did. Further, the particle diameter of the particles was read from the obtained image.

<Fabrication of crystalline tin-containing indium oxide fine particles>
The crystalline tin-containing indium oxide fine particle dispersion was filtered through a 0.5 μm filter and then dried under reduced pressure at a temperature at which the dispersion solvent could be removed to obtain crystalline tin-containing indium oxide fine particle powder.

<X-ray diffraction measurement of crystalline tin-containing indium oxide fine particles>
X-ray diffraction was measured using crystalline tin-containing indium oxide fine particle powder. For measurement, Spectris X'per PRO MPD (manufactured by PANalytical) was used, and measurement was performed in the range of 5 to 70 °.

<Measurement of tin content in crystalline tin-containing indium oxide fine particles>
The crystalline tin-containing indium oxide fine particle powder was used, and the metal composition in the fine particle was analyzed by inductively coupled plasma. For the measurement, an inductively coupled argon plasma emission spectroscopic analyzer (Vista-PRO axial specification) manufactured by Seiko Instruments Inc. was used.

<Amine ligand content analysis in crystalline tin-containing indium oxide fine particles>
Crystalline tin-containing indium oxide fine particles were used and analyzed by thermogravimetry. For the measurement, (trade name) EXSTAR TG / DTA6200 manufactured by SII Nanotechnology Inc. was used. The fine particle powder is held at 100 ° C. for 60 minutes in a nitrogen atmosphere, then heated to 500 ° C. at 10 ° C. per minute, then held at 500 ° C. for 180 minutes, and the weight reduction value in the range of 100 ° C. to 500 ° C. The amount of amine ligand decomposed by heating was calculated.

<Measurement of free amine ligand in dispersion>
After adding a large excess of precipitation solvent to the crystalline tin-containing indium oxide fine particle dispersion, only the same fine particles are precipitated by centrifugation, and the resulting supernatant is analyzed to coordinate the fine particles in the dispersion. Quantification of free amine ligands that were not performed was performed. Gas chromatography ((trade name) GC-14A, manufactured by Shimadzu Corporation) was used for the measurement.

<Measurement of conductivity of transparent conductive film>
Using a resistivity meter ((trade name) Loresta-AP, manufactured by Mitsubishi Yuka Co., Ltd.), sheet resistance was measured by a four-probe method.

<Measurement of light transmittance and haze of dispersion of crystalline tin-containing indium oxide fine particles>
Using a Nippon Denshoku Industries Co., Ltd. haze meter ((trade name) NDH-5000, manufactured by Nippon Denshoku Industries Co., Ltd.), the dispersion is put into a liquid cell having a thickness of 10 mm, and conforms to JIS K 7361-1. The haze of the light transmittance of the crystalline tin-containing indium fine particle dispersion was measured according to JIS K7136.

<Measurement of light transmittance and haze of transparent conductive film>
Using a haze meter ((trade name) NDH-5000, manufactured by Nippon Denshoku Industries Co., Ltd.), the light transmittance of the transparent conductive film according to JIS K 7361-1, and the haze value according to JIS K 7136. Measurements were made.

<Evaluation of solvent resistance of transparent conductive film>
After immersing the transparent conductive film in an organic solvent used as a dispersion solvent before film formation for 3 hours, drying the transparent conductive film at a temperature at which the solvent can be removed, and measuring the weight change before and after immersion, The weight redispersed in the dispersion solvent was calculated, and the solvent resistance of the transparent conductive film was evaluated.

Example 1
Into a 100 ml flask was charged 315 mg of indium (III) acetate, 48.6 mg of tin (II) 2-ethylhexanoate, 600 μl of n-octanoic acid, 3.0 g of stearylamine, and 9 ml of n-dioctyl ether. Heated for a period of time, then returned to normal pressure, heated at 150 ° C. in a nitrogen atmosphere for 1 hour, then heated to reflux at 270 ° C. in a nitrogen atmosphere for 2 hours to coarsely disperse crystalline tin-containing indium oxide fine particles coordinated with stearylamine A liquid was obtained.

  The crude dispersion was repeatedly purified by centrifugal separation 5 times using methanol as the precipitation solvent and chloroform as the dispersion solvent, and then added with 10 ml of chloroform, and crystallinity in which stearylamine was coordinated with respect to 100 parts by weight of chloroform. A coating solution for a solvent-resistant transparent conductive film, which is a dispersion containing 1.5 parts by weight of tin-containing indium oxide, was obtained.

  When a part of the obtained solvent-resistant transparent conductive film coating solution was diluted and observed by TEM, the average particle diameter of the crystalline tin-containing indium oxide fine particles was 12.2 nm. Subsequently, when a part of the coating solution for solvent resistant transparent conductive film was dried to form a fine particle powder and X-ray diffraction was measured, (211) plane, (222) plane, (400) plane, (440) ) Plane and (622) plane were confirmed, and it was confirmed that it had a cubic bixbite structure. The tin / indium (molar ratio) of the fine particle powder was 10/90, and it was confirmed that stearylamine was coordinated by 4.5% by weight.

  The free stearylamine in the solvent-resistant transparent conductive film coating solution was 2100 ppm based on the weight of the crystalline tin-containing indium oxide fine particles coordinated with stearylamine, the light transmittance was 95%, and the haze was 0.00. It was 5%. Table 1 shows the evaluation results of the obtained solvent-resistant transparent conductive film coating solution.

The obtained coating solution for solvent-resistant transparent conductive film was applied to a glass plate as a substrate and dried at 25 ° C. for 10 hours to obtain a transparent conductive film having a coating thickness of 0.1 μm. This transparent conductive film has high adhesion to the base material of the coating film, has a light transmittance of 91%, a haze of 0.8%, a sheet resistance of 4 × 10 ³ Ω / □, and has high optical characteristics and conductive characteristics. It was.

  Subsequently, this transparent conductive film was immersed in chloroform for 3 hours, and then the coated film was dried at 60 ° C. for 1 hour under reduced pressure. As a result, the weight loss of the crystalline tin-containing indium oxide fine particles due to redispersion in chloroform was 0. It was confirmed that the coating film had sufficient solvent resistance as a transparent conductive film, and the coating film was not whitened or deteriorated in optical properties and conductive properties. Table 2 shows the evaluation results of the obtained transparent conductive film.

Example 2
A 100 ml flask was charged with 325 mg of indium (III) nitrate, 28.4 mg of tin (II) acetate, 500 μl of 2-ethylhexanoic acid, 3.5 g of tetradecylamine, and 15 ml of n-dioctyl ether, and heated in vacuum at 80 ° C. for 1 hour. Then, the pressure was returned to normal pressure, and the mixture was heated to reflux at 250 ° C. for 4 hours to obtain a coarse dispersion of crystalline tin-containing indium oxide fine particles coordinated with tetradecylamine.

  The crude dispersion was centrifuged and purified four times using ethanol as the precipitation solvent and chloroform as the dispersion solvent, and then 10 ml of chloroform was added, and tin with tetradecylamine coordinated to 100 parts by weight of chloroform was added. A coating solution for a solvent-resistant transparent conductive film, which is a dispersion containing 1.4 parts by weight of contained indium oxide fine particles, was obtained.

  When a part of the obtained solvent-resistant transparent conductive film coating solution was diluted and observed by TEM, the average particle diameter of the crystalline tin-containing indium oxide fine particles was 7.8 nm. Subsequently, when a part of the coating solution for solvent resistant transparent conductive film was dried to form a fine particle powder and X-ray diffraction was measured, (211) plane, (222) plane, (400) plane, (440) ) Plane and (622) plane were confirmed, and it was confirmed that it had a cubic bixbite structure. The tin / indium (molar ratio) of the fine particle powder was 10/90, and it was confirmed that tetradecylamine was coordinated with 4.9% by weight.

  The free tetradecylamine in the solvent-resistant transparent conductive film coating solution was 8300 ppm based on the weight of the crystalline tin-containing indium oxide fine particles coordinated with tetradecylamine, and had a light transmittance of 93% and haze. 1.0%. Table 1 shows the evaluation results of the obtained solvent-resistant transparent conductive film coating solution.

The obtained coating solution for solvent-resistant transparent conductive film was applied to a glass plate as a substrate and dried at 100 ° C. for 1 hour to obtain a transparent conductive film having a coating thickness of 0.08 μm. This transparent conductive film has high adhesion to the base material of the coating film, has a light transmittance of 88%, a haze of 1.0%, a sheet resistance of 4 × 10 ⁴ Ω / □, and has high optical and conductive properties. It was.

  Next, this transparent conductive film was immersed in chloroform for 3 hours, and then the coating film was dried in a nitrogen stream at 50 ° C. for 3 hours. The weight reduction of the crystalline tin-containing indium oxide fine particles due to redispersion in chloroform was as follows. It was 0.5% by weight, and it was confirmed that the coating film had sufficient solvent resistance as a transparent conductive film without whitening of the coating film, deterioration of optical characteristics and conductive characteristics. Table 2 shows the evaluation results of the obtained transparent conductive film.

Example 3
Into a 100 ml flask was charged 280 mg of indium (III) acetate, 56.8 mg of tin (II) acetate, 600 μl of 2-ethylhexanoic acid, 2.7 g of behenylamine, and 10 ml of 1-octadecene, and heated at 70 ° C. for 30 minutes in a vacuum. Thereafter, the pressure is returned to normal pressure, and the mixture is heated at 150 ° C. for 1 hour in a nitrogen atmosphere and then heated to reflux at 270 ° C. for 2 hours in a nitrogen atmosphere to obtain a coarse dispersion of crystalline tin-containing indium oxide fine particles coordinated with behenylamine It was.

  The crude dispersion was repeatedly purified by centrifugal separation 5 times using isopropanol as a precipitation solvent and hexane as a dispersion solvent, and then added with 5 ml of hexane, and crystallinity in which behenylamine was coordinated with respect to 100 parts by weight of hexane. A coating solution for a solvent-resistant transparent conductive film, which is a dispersion containing 3.0 parts by weight of tin-containing indium oxide fine particles, was obtained.

  When a part of the obtained solvent-resistant transparent conductive film coating solution was diluted and observed by TEM, the average particle diameter of the crystalline tin-containing indium oxide fine particles was 13.5 nm. Subsequently, when a part of the coating solution for solvent resistant transparent conductive film was dried to form a fine particle powder and X-ray diffraction was measured, (211) plane, (222) plane, (400) plane, (440) ) Plane and (622) plane were confirmed, and it was confirmed that it had a cubic bixbite structure. The tin / indium (molar ratio) of the fine particle powder was 20/80, and it was confirmed that behenylamine was coordinated with 2.8% by weight.

  Further, the free behenylamine in the solvent-resistant transparent conductive film coating solution was 8900 ppm with respect to the weight of the crystalline tin-containing indium oxide fine particles coordinated with behenylamine, the light transmittance was 93%, and the haze was 1. It was 5%. Table 1 shows the evaluation results of the obtained solvent-resistant transparent conductive film coating solution.

The obtained coating solution for solvent-resistant transparent conductive film is coated on a glass plate as a base material, dried at 70 ° C. for 30 minutes, and then dried at 180 ° C. for 1 hour to obtain a transparent coating having a thickness of 0.3 μm. A conductive film was obtained. This transparent conductive film has high adhesion to the base material of the coating film, has a light transmittance of 89%, a haze of 1.6%, a sheet resistance of 8 × 10 ² Ω / □, and has high optical properties and conductive properties. It was.

  Next, this transparent conductive film was immersed in hexane for 3 hours, and then the coating film was dried in a nitrogen stream at 60 ° C. for 3 hours. As a result, the weight loss of the crystalline tin-containing indium oxide fine particles due to redispersion in hexane was It was 1.0% by weight, and it was confirmed that the coating film had sufficient solvent resistance as a transparent conductive film without whitening of the coating film, deterioration of optical characteristics and conductive characteristics. Table 2 shows the evaluation results of the obtained transparent conductive film.

Example 4
Into a 100 ml flask was charged 457 mg of indium (III) 2-ethylhexanoate, 145.8 mg of tin (II) 2-ethylhexanoate, 300 μl of pivalic acid, 3.0 g of oleylamine, 10 ml of 1-octadecene, and 30 at 30 ° C. in vacuum. The mixture was heated for 4 minutes, and then returned to normal pressure and heated to reflux in a nitrogen atmosphere at 250 ° C. for 4 hours to obtain a coarse dispersion of crystalline tin-containing indium oxide fine particles coordinated with oleylamine.

  The crude dispersion was centrifuged and purified five times using ethanol as the precipitation solvent and hexane as the dispersion solvent, then 10 ml of hexane was added, and crystalline tin coordinated with oleylamine was added to 100 parts by weight of hexane. A coating solution for a solvent-resistant transparent conductive film, which is a dispersion containing 1.2 parts by weight of contained indium oxide fine particles, was obtained.

  When a part of the obtained solvent-resistant transparent conductive film coating solution was diluted and observed by TEM, the average particle diameter of the tin-containing indium oxide fine particles was 9.5 nm. Subsequently, when a part of the coating solution for solvent resistant transparent conductive film was dried to form a fine particle powder and X-ray diffraction was measured, (211) plane, (222) plane, (400) plane, (440) ) Plane and (622) plane were confirmed, and it was confirmed that it had a cubic bixbite structure. The tin / indium (molar ratio) of the fine particle powder was 30/70, and it was confirmed that oleylamine was coordinated by 3.7% by weight.

  Further, the free oleylamine of the solvent-resistant transparent conductive film coating solution was 6800 ppm based on the weight of the crystalline tin-containing indium oxide fine particles coordinated with oleylamine, light transmittance of 93%, and haze of 1.0%. Met. Table 1 shows the evaluation results of the obtained solvent-resistant transparent conductive film coating solution.

The obtained coating solution for solvent-resistant transparent conductive film was applied to a glass plate as a substrate and dried at 150 ° C. for 1 hour to obtain a transparent conductive film having a coating thickness of 0.2 μm. This transparent conductive film has high adhesion to the base material of the coating film, has a light transmittance of 92%, a haze of 0.8%, a sheet resistance of 2 × 10 ³ Ω / □, and has high optical and conductive properties. It was.

  Next, this transparent conductive film was immersed in hexane for 3 hours, and then the coating film was dried in a nitrogen stream at 50 ° C. for 5 hours. As a result, the weight reduction of the tin-containing indium oxide fine particles due to redispersion in hexane was 0. It was 2% by weight, and it was confirmed that the coating film had sufficient solvent resistance as a transparent conductive film without whitening of the coating film, deterioration of optical characteristics and conductive characteristics. Table 2 shows the evaluation results of the obtained transparent conductive film.

Example 5
In the same manner as in Example 1, a solvent-resistant transparent conductive film coating solution was obtained.

The obtained coating solution for solvent-resistant transparent conductive film was applied to a PET film as a substrate and dried at 50 ° C. for 1 hour to obtain a transparent conductive film having a coating thickness of 0.05 μm. This transparent conductive film has high adhesion to the base material of the coating film, has a light transmittance of 91%, a haze of 1.8%, a sheet resistance of 5 × 10 ³ Ω / □, and has high optical and conductive properties. It was.

  Subsequently, this transparent conductive film was immersed in chloroform for 3 hours, and then the coated film was dried at 60 ° C. for 1 hour under reduced pressure. As a result, the weight loss of the crystalline tin-containing indium oxide fine particles due to redispersion in chloroform was 0. It was confirmed that the coating film had sufficient solvent resistance as a transparent conductive film, and the coating film was not whitened or deteriorated in optical properties and conductive properties. Table 2 shows the evaluation results of the obtained transparent conductive film.

Example 6
In the same manner as in Example 2, a solvent-resistant transparent conductive film coating solution was obtained.

The obtained coating solution for solvent-resistant transparent conductive film was applied to a PET film as a substrate and dried at 40 ° C. for 5 hours to obtain a transparent conductive film having a coating thickness of 0.1 μm. This transparent conductive film has high adhesion to the base material of the coating film, has a light transmittance of 86%, a haze of 1.3%, a sheet resistance of 2 × 10 ⁴ Ω / □, and has high optical properties and conductive properties. It was.

  Next, this transparent conductive film was immersed in chloroform for 3 hours, and then the coating film was dried in a nitrogen stream at 50 ° C. for 3 hours. The weight reduction of the crystalline tin-containing indium oxide fine particles due to redispersion in chloroform was as follows. It was 1.0% by weight, and it was confirmed that the coating film had sufficient solvent resistance as a transparent conductive film without whitening of the coating film, deterioration of optical characteristics and conductive characteristics. Table 2 shows the evaluation results of the obtained transparent conductive film.

Example 7
In the same manner as in Example 3, a solvent-resistant transparent conductive film coating solution was obtained.

The obtained coating solution for solvent-resistant transparent conductive film is applied to a PET film as a base material and dried at 70 ° C. for 30 minutes and then at 140 ° C. for 30 minutes to form a transparent conductive film having a coating thickness of 0.3 μm. A membrane was obtained. This transparent conductive film has high adhesion to the base material of the coating film, has a light transmittance of 85%, a haze of 2.0%, a sheet resistance of 9 × 10 ² Ω / □, and has high optical properties and conductive properties. It was.

  Next, this transparent conductive film was immersed in hexane for 3 hours, and then the coating film was dried in a nitrogen stream at 60 ° C. for 3 hours. As a result, the weight loss of the crystalline tin-containing indium oxide fine particles due to redispersion in hexane was It was 1.0% by weight, and it was confirmed that the coating film had sufficient solvent resistance as a transparent conductive film without whitening of the coating film, deterioration of optical characteristics and conductive characteristics. Table 2 shows the evaluation results of the obtained transparent conductive film.

Example 8
In the same manner as in Example 4, a solvent-resistant transparent conductive film coating solution was obtained.

The obtained coating solution for solvent-resistant transparent conductive film was applied to a PET film as a substrate and dried at 80 ° C. for 1 hour to obtain a transparent conductive film having a coating thickness of 0.1 μm. This transparent conductive film has high adhesion to the base material of the coating film, has a light transmittance of 92%, a haze of 1.0%, a sheet resistance of 8 × 10 ³ Ω / □, and has high optical and conductive properties. It was.

  Next, this transparent conductive film was immersed in hexane for 3 hours, and then the coating film was dried in a nitrogen stream at 60 ° C. for 3 hours. As a result, the weight loss of the crystalline tin-containing indium oxide fine particles due to redispersion in hexane was It was 0.2% by weight, and whitening of the coating film, optical characteristics, and deterioration of conductive characteristics were not observed, and it was confirmed that the film had sufficient solvent resistance as a transparent conductive film. Table 2 shows the evaluation results of the obtained transparent conductive film.

Example 9
Except that the amount of tin (II) 2-ethylhexanoate was changed to 77.0 mg and the amount of stearylamine was changed to 4 g, in the same manner as in Example 1, stearylamine was added to 100 parts by weight of chloroform. A coating solution for a solvent-resistant transparent conductive film, which is a dispersion containing 1.8 parts by weight of coordinated crystalline tin-containing indium oxide, was obtained.

  When a part of the obtained solvent-resistant transparent conductive film coating solution was diluted and observed by TEM, the average particle diameter of the crystalline tin-containing indium oxide fine particles was 15.1 nm. Subsequently, when a part of the coating liquid was dried to form a fine particle powder and X-ray diffraction was measured, the (211) plane, (222) plane, (400) plane, (440) plane, (622) plane Was confirmed, and it was confirmed to have a cubic bixbite structure. The tin / indium (molar ratio) of the fine particle powder was 15/85, and it was confirmed that stearylamine was coordinated by 5.1% by weight.

  The free stearylamine in the solvent-resistant transparent conductive film coating solution was 2300 ppm with respect to the weight of the crystalline tin-containing indium oxide fine particles coordinated with stearylamine, the light transmittance was 94%, and the haze was 0.00. It was 6%. Table 1 shows the evaluation results of the obtained solvent-resistant transparent conductive film coating solution.

The obtained coating solution for solvent-resistant transparent conductive film was applied to a glass plate as a substrate and dried at 25 ° C. for 1 hour and in a nitrogen atmosphere at 200 ° C. for 1 hour, and the coating thickness was 0.1 μm. A transparent conductive film was obtained. This transparent conductive film has high adhesion to the base material of the coating film, has a light transmittance of 90%, a haze of 1.6%, a sheet resistance of 9 × 10 ² Ω / □, and has high optical and conductive properties. It was.

  Subsequently, this transparent conductive film was immersed in chloroform for 3 hours, and then the coated film was dried at 60 ° C. for 1 hour under reduced pressure. As a result, the weight loss of the crystalline tin-containing indium oxide fine particles due to redispersion in chloroform was 0. It was confirmed that the coating film had sufficient solvent resistance as a transparent conductive film, and the coating film was not whitened or deteriorated in optical properties and conductive properties. Table 2 shows the evaluation results of the obtained transparent conductive film.

Example 10
Crystalline tin-containing indium oxide with tetradecylamine coordinated to 100 parts by weight of chloroform by the same method as in Example 2 except that the amount of tin (II) acetate was changed to 23.7 mg. A coating solution for a solvent-resistant transparent conductive film, which is a dispersion containing 9 parts by weight, was obtained.

  When a part of the obtained solvent-resistant transparent conductive film coating solution was diluted and observed by TEM, the average particle diameter of the crystalline tin-containing indium oxide fine particles was 8.3 nm. Subsequently, when a part of the coating liquid was dried to form a fine particle powder and X-ray diffraction was measured, the (211) plane, (222) plane, (400) plane, (440) plane, (622) plane Was confirmed, and it was confirmed to have a cubic bixbite structure. The tin / indium (molar ratio) of the fine particle powder was 8/92, and it was confirmed that tetradecylamine was coordinated with 6.9% by weight.

  The free tetradecylamine in the solvent-resistant transparent conductive film coating solution was 7900 ppm based on the weight of the crystalline tin-containing indium oxide fine particles coordinated with tetradecylamine, and had a light transmittance of 95% and haze. It was 0.9%. Table 1 shows the evaluation results of the obtained solvent-resistant transparent conductive film coating solution.

The obtained coating solution for solvent-resistant transparent conductive film is applied to a glass plate as a substrate, dried at 100 ° C. for 1 hour, then at 200 ° C. for 1 hour, and a transparent conductive film having a coating thickness of 0.08 μm. A membrane was obtained. This transparent conductive film has high adhesion to the base material of the coating film, has a light transmittance of 88%, a haze of 1.3%, a sheet resistance of 6 × 10 ³ Ω / □, and has high optical characteristics and conductive characteristics. It was.

  Next, this transparent conductive film was immersed in chloroform for 3 hours, and then the coating film was dried in a nitrogen stream at 50 ° C. for 3 hours. The weight reduction of the crystalline tin-containing indium oxide fine particles due to redispersion in chloroform was as follows. It was 0.4% by weight, and whitening of the coating film, optical characteristics, and deterioration of conductive characteristics were not observed, and it was confirmed that the film had sufficient solvent resistance as a transparent conductive film. Table 2 shows the evaluation results of the obtained transparent conductive film.

Example 11
Crystalline tin coordinated with hebenylamine with respect to 100 parts by weight of hexane by the same method as in Example 3 except that the charged amount of tin (II) acetate was changed to 49.7 mg and the charged amount of hebenylamine was changed to 3 g. A coating solution for a solvent-resistant transparent conductive film, which is a dispersion containing 4 parts by weight of contained indium oxide, was obtained.

  When a part of the obtained solvent-resistant transparent conductive film coating solution was diluted and observed by TEM, the average particle diameter of the crystalline tin-containing indium oxide fine particles was 15.3 nm. Subsequently, when a part of the coating liquid was dried to form a fine particle powder and X-ray diffraction was measured, the (211) plane, (222) plane, (400) plane, (440) plane, (622) plane Was confirmed, and it was confirmed to have a cubic bixbite structure. The tin / indium (molar ratio) of the fine particle powder was 18/82, and it was confirmed that hebenylamine was coordinated by 3.1% by weight.

  Further, the free hebenylamine in the coating solution for solvent-resistant transparent conductive film is 8800 ppm with respect to the weight of crystalline tin-containing indium oxide fine particles coordinated with hebenylamine, light transmittance of 93%, and haze of 1.2%. Met. Table 1 shows the evaluation results of the obtained solvent-resistant transparent conductive film coating solution.

The obtained coating solution for solvent-resistant transparent conductive film is applied to a glass plate as a substrate, dried at 60 ° C. for 30 minutes, and then dried at 180 ° C. in a nitrogen atmosphere for 200 minutes to obtain a coating thickness of 0.25 μm. A transparent conductive film was obtained. This transparent conductive film has high adhesion to the base material of the coating film, has a light transmittance of 85%, a haze of 2.0%, a sheet resistance of 5 × 10 ² Ω / □, and has high optical and conductive properties. It was.

  Next, this transparent conductive film was immersed in hexane for 3 hours, and then the coating film was dried in a nitrogen stream at 60 ° C. for 3 hours. As a result, the weight loss of the crystalline tin-containing indium oxide fine particles due to redispersion in hexane was It was 0.8% by weight, and it was confirmed that the coating film had sufficient solvent resistance as a transparent conductive film without whitening of the coating film, deterioration of optical characteristics and conductive characteristics. Table 2 shows the evaluation results of the obtained transparent conductive film.

Example 12
The amount of tin (II) acetate was changed to 113.4 mg, the amount of oleylamine was changed to 2.5 g, and the dispersion solvent was changed to toluene. Thus, a coating solution for a solvent-resistant transparent conductive film, which is a dispersion containing 1.1 parts by weight of crystalline tin-containing indium oxide coordinated with oleylamine, was obtained.

  When a part of the obtained solvent-resistant transparent conductive film coating solution was diluted and observed by TEM, the average particle diameter of the crystalline tin-containing indium oxide fine particles was 9.1 nm. Subsequently, when a part of the coating liquid was dried to form a fine particle powder and X-ray diffraction was measured, the (211) plane, (222) plane, (400) plane, (440) plane, (622) plane Was confirmed, and it was confirmed to have a cubic bixbite structure. It was confirmed that tin / indium (molar ratio) of the fine particle powder was 25/75 and oleylamine was coordinated by 3.8% by weight.

  Further, the free oleylamine in the solvent-resistant transparent conductive film coating solution is 7000 ppm with respect to the weight of the crystalline tin-containing indium oxide fine particles coordinated with oleylamine, and has a light transmittance of 93% and a haze of 1.0%. Met. Table 1 shows the evaluation results of the obtained solvent-resistant transparent conductive film coating solution.

The obtained coating solution for solvent-resistant transparent conductive film is applied to a glass plate as a base material and dried at 60 ° C. for 1 hour and then at 220 ° C. for 1 hour to form a transparent conductive film having a coating thickness of 0.08 μm. A membrane was obtained. This transparent conductive film has high adhesion to the base material of the coating film, has a light transmittance of 90%, a haze of 1.0%, a sheet resistance of 1 × 10 ³ Ω / □, and has high optical properties and conductive properties. It was.

  Next, this transparent conductive film was immersed in toluene for 3 hours, and then the coating film was dried in a nitrogen stream at 60 ° C. for 3 hours. As a result, the weight loss of the crystalline tin-containing indium oxide fine particles due to redispersion in toluene was reduced. It was 0.2% by weight, and whitening of the coating film, optical characteristics, and deterioration of conductive characteristics were not observed, and it was confirmed that the film had sufficient solvent resistance as a transparent conductive film. Table 2 shows the evaluation results of the obtained transparent conductive film.

比較例１
平均粒径２０ｎｍの非晶質スズ含有酸化インジウム（ＩＴＯ）微粒子（シーアイ化成社製、（商品名）ＮａｎｏＴｅｃｋ ＩＴＯ）０．３ｇ、分散剤として脂肪族リン酸エステル型界面活性剤（旭電化工業（株）製、（商品名）ＰＳ−４４０Ｅ）５０ｍｇ、分散溶剤としてトルエン５ｇを混合した後、ジルコニアビーズを用いたペイントシェーカーにより湿式粉砕して、ＩＴＯ微粒子分散液を調製した。

Comparative Example 1
Amorphous tin-containing indium oxide (ITO) fine particles having an average particle size of 20 nm (manufactured by CI Kasei Co., Ltd., (trade name) NanoCheck ITO) 0.3 g, aliphatic phosphate ester type surfactant (Asahi Denka Kogyo Co., Ltd.) (Trade name) PS-440E) 50 mg and 5 g of toluene as a dispersion solvent were mixed, and then wet pulverized with a paint shaker using zirconia beads to prepare an ITO fine particle dispersion.

The ITO fine particle dispersion was applied to a glass plate as a base material and heated at 300 ° C. for 3 hours to remove the organic solvent and the dispersing agent to obtain a coating film having a coating thickness of 0.3 μm. The obtained coating film is inferior in transparency with a light transmittance of 60% and a haze of 20%, and has a sheet resistance of 9.9 × 10 ⁷ or more and cannot be measured accurately, and consists of amorphous tin-containing indium oxide. Since it is a coating film, the conductivity as a conductive film was insufficient. Table 4 shows the evaluation results of the obtained coating film.

Comparative Example 2
Except for changing the charge amount of indium (III) acetate to 339 mg and the charge amount of tin (II) 2-ethylhexanoate to 14.6 mg, in the same manner as in Example 1, with respect to 100 parts by weight of chloroform, A coating liquid which was a dispersion containing 1.5 parts by weight of crystalline tin-containing indium oxide coordinated with stearylamine was obtained.

  When a part of the obtained coating solution was diluted and observed by TEM, the average particle diameter of the crystalline tin-containing indium oxide fine particles was 7.5 nm. Subsequently, when a part of the coating liquid was dried to form a fine particle powder and X-ray diffraction was measured, the (211) plane, (222) plane, (400) plane, (440) plane, (622) plane Was confirmed, and it was confirmed to have a cubic bixbite structure. It was confirmed that tin / indium (molar ratio) of the fine particle powder was 3/97, and stearylamine was coordinated by 4.5% by weight.

  The free stearylamine in the coating solution was 5000 ppm with respect to the weight of the crystalline tin-containing indium oxide fine particles coordinated with stearylamine, the light transmittance was 89%, and the haze was 0.9%. Table 3 shows the evaluation results of the obtained coating solution.

The obtained coating solution was applied to a glass plate as a substrate and dried at 25 ° C. for 10 hours to obtain a coating film having a coating thickness of 0.1 μm. This coating film has high adhesion to the base material of the coating film, and has a light transmittance of 91% and a haze of 0.8%, but is made of crystalline tin-containing indium oxide fine particles with a small Sn content. The resistance was as high as 4 × 10 ⁶ Ω / □, and the conductivity as a conductive film was insufficient. Table 4 shows the evaluation results of the obtained coating film.

Comparative Example 3
Crystalline tin-containing indium oxide coordinated with tetradecylamine to 1.1 parts by weight with respect to 100 parts by weight of chloroform in the same manner as in Example 2 except that the charged amount of tetradecylamine was changed to 1.7 g. The coating liquid which is the dispersion liquid containing a part was obtained.

  When a part of the obtained coating liquid was diluted and observed by TEM, the average particle diameter of the crystalline tin-containing indium oxide fine particles was 4.0 nm. Subsequently, when a part of the coating liquid was dried to form a fine particle powder and X-ray diffraction was measured, the (211) plane, (222) plane, (400) plane, (440) plane, (622) plane Was confirmed, and it was confirmed to have a cubic bixbite structure. The tin / indium (molar ratio) of the fine particle powder was 10/90, and it was confirmed that tetradecylamine was 8.0% by weight coordinated.

  The free tetradecylamine of the coating solution was 9000 ppm with respect to the weight of the crystalline tin-containing indium oxide fine particles coordinated with tetradecylamine, the light transmittance was 92%, and the haze was 1.1%. . Table 3 shows the evaluation results of the obtained coating solution.

The obtained coating liquid was applied to a glass plate as a substrate and dried at 100 ° C. for 1 hour to obtain a coating film having a coating thickness of 0.1 μm. This coating film had high adhesion to the base material of the coating film and had a light transmittance of 90% and a haze of 1.0%, but the particle diameter of the crystalline tin-containing indium oxide fine particles was small. The sheet resistance was as high as 5 × 10 ⁷ Ω / □, and the conductivity as a conductive film was insufficient. Table 4 shows the evaluation results of the obtained coating film.

Comparative Example 4
Except for changing the amine ligand to 2.6 g of n-butylamine, in the same manner as in Example 1, with respect to 100 parts by weight of chloroform, crystalline tin-containing indium oxide 1.5% coordinated with n-butylamine A coating liquid which is a dispersion containing parts by weight was obtained.

  The crystalline tin-containing indium oxide fine particles in the coating liquid have a low chain stability of the amine ligand, so the dispersion stability is low, the light transmittance of the dispersion is 69%, and the haze is 10.9%. Yes, it was a coating liquid with insufficient transparency as a coating liquid for a transparent conductive film. Table 3 shows the evaluation results of the obtained coating solution.

Comparative Example 5
A dispersion containing 1.5 parts by weight of crystalline tin-containing indium oxide coordinated with stearylamine with respect to 100 parts by weight of chloroform in the same manner as in Example 1 except that the amount of stearylamine charged was changed to 10 g. The coating liquid which is a liquid was obtained.

  When a part of the obtained coating liquid was diluted and observed by TEM, the average particle diameter of the crystalline tin-containing indium oxide fine particles was 12.5 nm. Subsequently, when a part of the coating solution for solvent resistant transparent conductive film was dried to form a fine particle powder and X-ray diffraction was measured, (211) plane, (222) plane, (400) plane, (440) ) Plane and (622) plane were confirmed, and it was confirmed that it had a cubic bixbite structure. The tin / indium (molar ratio) of the fine particle powder was 10/90, and it was confirmed that stearylamine was coordinated by 11.0% by weight.

  Further, the free stearylamine in the coating solution was 28000 ppm with respect to the weight of the crystalline tin-containing indium oxide fine particles coordinated with stearylamine, the light transmittance was 85%, and the haze was 1.9%. Table 3 shows the evaluation results of the obtained coating solution.

  The obtained coating solution was applied to a glass plate as a substrate and dried at 25 ° C. for 10 hours to obtain a coating film having a coating thickness of 0.1 μm.

  Subsequently, this coated film was immersed in chloroform for 3 hours, and then the coated film was dried at 60 ° C. for 1 hour under reduced pressure. As a result, the weight reduction of the tin-containing indium oxide fine particles due to redispersion in chloroform was 12.4. The solvent was insufficient as a conductive film. Table 4 shows the evaluation results of the obtained coating film.

  The present invention provides a coating solution for a solvent-resistant transparent conductive film comprising a dispersion having excellent dispersion stability containing crystalline tin-containing indium oxide fine particles, and the coating for the solvent-resistant transparent conductive film By applying the liquid, it is possible to easily provide a transparent conductive film having excellent electrical characteristics, optical characteristics, and solvent resistance.

Claims (9)

Solvent resistance characterized by being a dispersion containing 0.1 to 100 parts by weight of crystalline tin-containing indium oxide fine particles having at least the following properties (a) to (d) with respect to 100 parts by weight of the dispersion solvent Coating liquid for transparent conductive film.
(A) a cubic bixbite structure;
(B) Tin / indium (molar ratio) measured by an inductively coupled plasma optical emission spectrometer (ICP) is in the range of 5/95 to 40/60.
(C) The average particle diameter measured by a transmission electron microscope is in the range of 5 to 20 nm.
(D) Coordinates 1 to 10% by weight of an amine ligand having 6 to 24 carbon atoms. The crystalline tin-containing indium oxide fine particles are crystalline tin-containing indium oxide fine particles obtained by heating indium carboxylate, tin carboxylate, and an amine ligand having 6 to 24 carbon atoms to 220 ° C. or higher. The manufacturing method which manufactures the coating liquid for solvent-resistant transparent conductive films of Claim 1 to do. The solvent-resistant transparent conductive film according to claim 1, wherein the light transmittance measured in accordance with JIS K 7361-1 is 90% or more and the haze measured in accordance with JIS K 7136 is 2% or less. Manufacturing method for manufacturing coating liquid. Content of free amine ligand having 6 to 24 carbon atoms in the dispersion, solvent resistance transparent according to claim 1, characterized in that not more than 10000ppm by weight of the crystalline tin-containing indium oxide fine particles The manufacturing method which manufactures the coating liquid for electrically conductive films. The manufacturing method according to claim coated 1 solvent resistance transparent conductive film coating solution according to on the substrate, to produce a solvent resistant transparent conductive film, wherein the drying child. The sheet resistance value of the solvent resistant transparent conductive film is 10 ⁵ Ω / □ or less, The production method for producing the solvent resistant transparent conductive film according to claim 5. The light transmittance of the solvent-resistant transparent conductive film measured according to JIS K 7361-1 is 80% or more, and the haze measured according to JIS K 7136 is 5% or less. The manufacturing method which manufactures the solvent-resistant transparent conductive film of description. The method for producing a solvent-resistant transparent conductive film according to any one of claims 5 to 7, wherein the temperature during coating and drying is 200 ° C or lower. The weight reduction | decrease when immersed in the dispersion solvent which comprises the coating liquid for solvent-resistant transparent conductive films of Claim 1 is 10 weight% or less, The any one of Claims 5-8 characterized by the above-mentioned. A method for producing a solvent-resistant transparent conductive film.