JP4411672B2 - Coating liquid for forming transparent conductive layer and method for producing the same - Google Patents

Description

【０１００】
『耐候性試験』
実施例１〜７、参考例１〜４に係る透明導電性基材と比較例１に係る透明導電性基材を、５％食塩水に浸漬し、透明基板（ガラス基板）上に設けた透明２層膜の表面抵抗値、膜の外観を調べた。この結果を以下の表２に示す。
【０１０１】
【表２】

【０１０２】
『評 価』
（１）表１に示された結果から明らかなように、実施例１〜７、参考例１〜４に係る透明２層膜の表面抵抗（Ω／□）と透過率の標準偏差の値が、各比較例に係る透明２層膜の値と較べて著しく改善されていることが確認される。また、図２と図１２に示された実施例１および参考例１に係る透明導電性基材の透過プロファイルと比較例１に係る透明導電性基材の透過プロファイルの比較から明らかなように、実施例１および参考例１の透明導電性基材では非常にフラットな透過プロファイルが得られていることも確認される。
また、図１と図１１の反射プロファイルから明らかなように、比較例１、２に較べて実施例１および参考例１に係る透明導電性基材では可視光線波長域における反射特性も改善されていることが確認される。
（２）また、表２に示された結果から明らかなように、比較例１に係る透明２層膜に較べて実施例１〜７、参考例１〜４に係る透明２層膜の耐候性も著しく改善されていることが確認される。
（３）次に、金単体がコーティングされた貴金属コート銀微粒子を適用している実施例１〜７に係る透明導電性基材の可視光線透過率を比較した場合、表１から確認されるようにＩＴＯを含ませた実施例５とＡＴＯを含ませた実施例６の可視光線透過率が他の実施例に較べて高い値を示している。
【０１０３】
他方、白金単体または金、白金複合体がコーティングされた貴金属コート銀微粒子を適用している参考例１〜４に係る透明導電性基材の表面抵抗を比較した場合、表１から確認されるようにＩＴＯを含ませた参考例４の表面抵抗が一番小さな値になっており、かつ、可視光線透過率についてはそれぞれ略同一の値になっている。すなわち、参考例４で、参考例１〜３の表面抵抗値と略同一となるように透明導電層の厚みをより薄く設定した場合、透明導電層の可視光線透過率を参考例１〜３より高くできることを示している。
【０１０４】
これ等からＩＴＯやＡＴＯ等の導電性酸化物微粒子を透明導電層内に含ませた場合、透明導電層における膜透過率の向上を図れることが確認される。
（４）尚、実施例１〜７、参考例１〜４においては、上記金酸塩と白金酸塩として金酸カリウムおよび白金酸カリウムを適用して貴金属コート銀微粒子を調製しているが、これ等金酸カリウムおよび白金酸カリウムに代えて金酸ナトリウムおよび白金酸ナトリウムを適用した実験も行っている。
【０１０５】
そして、金酸ナトリウムおよび白金酸ナトリウムを適用して得られた貴金属コート銀微粒子についても実施例１〜７、参考例１〜４と同様の評価試験を行い、かつ、同様の評価が得られることを確認している。
【０１０６】
【発明の効果】
請求項１〜５記載の発明に係る透明導電層形成用塗布液によれば、
溶媒、および、この溶媒に分散されかつ表面に金単体がコーティングされた平均粒径１〜１００ｎｍの貴金属コート銀微粒子を主成分としているため、従来の透明導電層形成用塗布液が適用された透明導電層と比較して、良好な反射防止機能と電界シールド機能を有しかつ可視光線域での透過光線プロファイルと耐候性も良好な透明導電層を形成できる効果を有する。
【０１０７】
また、請求項６〜８記載の発明に係る透明導電層形成用塗布液の製造方法によれば、
本発明に係る透明導電層形成用塗布液を低コストでかつ簡便に製造できる効果を有する。
【図面の簡単な説明】
【図１】実施例１および比較例１〜２に係る透明導電性基材の反射プロファイルを示すグラフ図。
【図２】実施例１および比較例１に係る透明導電性基材の透過プロファイルを示すグラフ図。
【図３】実施例１に係る透明導電性基材の反射プロファイルを示すグラフ図。
【図４】実施例１に係る透明導電性基材とこの基材の構成部材であるガラス基板の透過プロファイルを示すグラフ図。
【図５】実施例２に係る透明導電性基材の反射プロファイルを示すグラフ図。
【図６】実施例２に係る透明導電性基材とこの基材の構成部材であるガラス基板の透過プロファイルを示すグラフ図。
【図７】実施例５に係る透明導電性基材の反射プロファイルを示すグラフ図。
【図８】実施例５に係る透明導電性基材とこの基材の構成部材であるガラス基板の透過プロファイルを示すグラフ図。
【図９】実施例６に係る透明導電性基材の反射プロファイルを示すグラフ図。
【図１０】実施例６に係る透明導電性基材とこの基材の構成部材であるガラス基板の透過プロファイルを示すグラフ図。
【図１１】 参考例１および比較例１〜２に係る透明導電性基材の反射プロファイルを示すグラフ図。
【図１２】 参考例１および比較例１に係る透明導電性基材の透過プロファイルを示すグラフ図。
【図１３】 参考例１に係る透明導電性基材の反射プロファイルを示すグラフ図。
【図１４】 参考例１に係る透明導電性基材とこの基材の構成部材であるガラス基板の透過プロファイルを示すグラフ図。
【図１５】 参考例２に係る透明導電性基材の反射プロファイルを示すグラフ図。
【図１６】 参考例２に係る透明導電性基材とこの基材の構成部材であるガラス基板の透過プロファイルを示すグラフ図。
【図１７】 参考例４に係る透明導電性基材の反射プロファイルを示すグラフ図。
【図１８】 参考例４に係る透明導電性基材とこの基材の構成部材であるガラス基板の透過プロファイルを示すグラフ図。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a transparent conductive layer forming coating solution for forming a transparent conductive layer on a transparent substrate, and in particular, a cathode ray tube (CRT), a plasma display panel (PDP), a fluorescent display tube (VFD), a liquid crystal display ( When applied to the front plate of a display device such as an LCD), a transparent conductive layer that provides a good antireflection effect and electric field shielding effect, and can form a transparent conductive layer having a good transmitted light profile and good weather resistance in the visible light range. The present invention relates to an improvement of a coating liquid for layer formation and a method for producing the same.
[0002]
[Prior art]
In recent years, office automation (OA) has led to the introduction of many OA devices in the office, and it is not uncommon recently to have to work all day while facing the display of OA devices.
[0003]
By the way, when working in contact with a cathode ray tube of a computer (also referred to as the above-mentioned CRT) as an example of an OA device, the display screen is easy to see and the visual fatigue is not felt. It is required that there is no adhesion or electric shock. In addition to these, recently, there are concerns about the adverse effects of low frequency electromagnetic waves generated from CRTs on the human body, and it is desired for CRTs to prevent such electromagnetic waves from leaking to the outside.
[0004]
And the said electromagnetic waves generate | occur | produce from a deflection coil or a flyback transformer, and there exists a tendency for a lot of electromagnetic waves to leak to circumference | surroundings with the enlargement of a television.
[0005]
By the way, most of leakage of the magnetic field can be prevented by changing the shape of the deflection coil. On the other hand, electric field leakage can also be prevented by forming a transparent conductive layer on the front glass surface of the CRT.
[0006]
The method for preventing such electric field leakage is in principle the same as the countermeasures taken for the prevention of charging in recent years. However, the transparent conductive layer is required to have a much higher conductivity than the conductive layer formed for antistatic purposes. That is, the surface resistance is 10 for antistatic.⁸Ω / □ is sufficient, but at least 10 to prevent leakage electric field (electric field shielding).⁶Ω / □ or less, preferably 10^ThreeIt is necessary to form a transparent conductive layer having a low resistance of Ω / □ or less.
[0007]
Thus, several proposals have been made in the past to cope with the above requirements. Among them, as a method capable of realizing low surface resistance at a low cost, the conductive fine particles are placed in a solvent together with an inorganic binder such as an alkyl silicate. A method is known in which a dispersed transparent conductive layer forming coating solution is applied to a CRT front glass and dried, and then fired at a temperature of 200 ° C. or lower.
[0008]
The method using the coating liquid for forming the transparent conductive layer is much simpler than other methods for forming the transparent conductive layer such as vacuum deposition and sputtering, and the manufacturing cost is low, so that it can be processed into a CRT. This is a very advantageous method for electric field shielding.
[0009]
As the coating liquid for forming the transparent conductive layer used in this method, one in which indium tin oxide (ITO) is applied to conductive fine particles is known. However, the resulting film has a surface resistance of 10^Four-10⁶Since it is as high as Ω / □, a correction circuit for canceling the electric field is necessary to sufficiently shield the leakage electric field, and there is a problem that the manufacturing cost is increased accordingly. On the other hand, the coating liquid for forming a transparent conductive layer using metal powder as the conductive fine particles has a slightly lower film transmittance than the coating liquid using ITO, but 10²-10^ThreeA low resistance film of Ω / □ can be obtained. Accordingly, the above-described correction circuit is not necessary, which is advantageous in terms of cost and is expected to become mainstream in the future.
[0010]
As the metal fine particles applied to the coating liquid for forming the transparent conductive layer, silver, gold, and the like, which are hardly oxidized in the air as disclosed in JP-A-8-77832 and JP-A-9-55175, are disclosed. , Platinum, rhodium, palladium and other precious metals. This is because, when metal fine particles other than noble metals, such as iron, nickel, cobalt, etc., are applied, an oxide film is always formed on the surface of these metal fine particles in the air atmosphere, and a good conductive property as a transparent conductive layer. This is because sex cannot be obtained.
[0011]
On the other hand, in order to make the display screen easier to see, anti-glare treatment is performed on the face panel surface to suppress screen reflection. This anti-glare treatment is also performed by a method of increasing the diffuse reflection of the surface by providing fine irregularities. However, when this method is used, it is not a preferable method because the resolution is lowered and the image quality is lowered. Therefore, it is preferable to perform the antiglare treatment by an interference method that controls the refractive index and the film thickness of the transparent film so that the reflected light causes destructive interference with the incident light. In order to obtain a low reflection effect by such an interference method, the optical film thicknesses of the high refractive index film and the low refractive index film are generally set to 1 / 4λ and 1 / 4λ, or 1 / 2λ and 1 / 4λ, respectively. A set two-layer structure film is employed, and a film made of the aforementioned indium tin oxide (ITO) fine particles is also used as this type of high refractive index film.
[0012]
For metals, optical constants (n-ik, n: refractive index, i²= -1, k: extinction coefficient), the value of n is small, but the value of k is extremely large compared to ITO or the like. Therefore, even when a transparent conductive layer made of metal fine particles is used, ITO (high refractive index) Similarly to the film), the antireflection effect due to the interference of light can be obtained with the two-layer structure film.
[0013]
[Problems to be solved by the invention]
By the way, as described above, the metal fine particles applied to the conventional coating liquid for forming a transparent conductive layer are limited to noble metals such as silver, gold, platinum, rhodium, and palladium. The specific resistance of platinum, rhodium, and palladium is 10.6, 5.1, and 10.8 μΩ · cm, respectively, which is higher than 1.62 and 2.2 μΩ · cm of silver and gold. In order to form a transparent conductive layer having a low thickness, it was advantageous to apply silver fine particles or gold fine particles.
[0014]
However, when silver fine particles are applied, deterioration due to sulfidation or saline is severe and there is a problem in weather resistance. On the other hand, when gold fine particles are applied, the above-mentioned weather resistance problems are eliminated, but platinum fine particles, rhodium fine particles, palladium fine particles, etc. Had the same cost problem as when applied. Furthermore, when gold fine particles are applied, the transparent conductive layer itself formed by the optical characteristics peculiar to gold absorbs a part of visible light, so that a CRT that requires a flat transmitted light profile over the entire visible light is required. There is a problem that cannot be applied to the display surface of the display device.
[0015]
The present invention has been made paying attention to such problems, and the object of the present invention is to provide a good antireflection effect and electric field shielding effect when applied to the front plate of the display device such as the CRT. And providing a coating solution for forming a transparent conductive layer capable of forming a transparent conductive layer having a transmitted light profile in the visible light region and good weather resistance, and a method for producing the coating solution for forming the transparent conductive layer. It is in.
[0016]
[Means for Solving the Problems]
  That is, the invention according to claim 1
  The above transparent conductive substrate comprising a transparent substrate and a transparent two-layer film comprising a transparent conductive layer and a transparent coating layer sequentially formed on the transparent substrateAssuming a coating liquid for forming a transparent conductive layer for forming a transparent conductive layer,
  Solvent, and the surface of the silver fine particles dispersed in the solventGold aloneCharacterized in that the main component is precious metal-coated silver fine particles having an average particle diameter of 1 to 100 nm coated with
  The invention according to claim 2
  Based on the coating liquid for forming a transparent conductive layer according to the invention of claim 1,
  In the noble metal coated silver fine particlesGold aloneThe coating amount is set in the range of 5 to 100 parts by weight with respect to 100 parts by weight of silver.
[0017]
Next, the invention according to claim 3 is
Based on the coating liquid for forming a transparent conductive layer according to the invention of claim 1 or 2,
It contains conductive oxide fine particles,
The invention according to claim 4
Based on the coating liquid for forming a transparent conductive layer according to the invention of claim 3,
The conductive oxide fine particles are one or more fine particles selected from tin oxide, tin antimony oxide or indium tin oxide,
The invention according to claim 5
Based on the coating liquid for forming a transparent conductive layer according to any one of claims 1 to 4,
An inorganic binder is included.
[0018]
Next, the invention which concerns on Claims 6-8 is related with the invention which specified the manufacturing method of the said coating liquid for transparent conductive layer formation.
[0019]
  That is, the invention according to claim 6
  Based on the manufacturing method of the coating liquid for forming a transparent conductive layer according to claim 1, 3 or 5,
  In a colloidal dispersion of silver particles, a reducing agent and an alkali metalGold salt solutionOn the surface of the silver fine particlesGold aloneA precious metal-coated silver fine particle preparation step to obtain a colloidal dispersion of precious metal-coated silver fine particles,
  A desalting / concentration step for obtaining a dispersion concentrate of the noble metal-coated silver fine particles by performing a desalting treatment for reducing the electrolyte concentration in the colloidal dispersion of the noble metal-coated silver fine particles and a concentration treatment for concentrating the colloidal dispersion;
  Solvent blending step of obtaining a coating solution for forming a transparent conductive layer by adding a solvent alone or a solvent containing conductive oxide fine particles or / and an inorganic binder to the dispersion concentrate of the noble metal-coated silver fine particles,
  It is characterized by comprising each step of
  The invention according to claim 7 provides:
  Based on the manufacturing method of the coating liquid for forming a transparent conductive layer according to claim 1, 3 or 5,
  The colloidal dispersion of silver fine particlesGold salt solutionPlus silver,MoneyOn the surface of the silver fine particles by the substitution reaction due to the difference in ionization tendency ofGold aloneA precious metal-coated silver fine particle preparation step to obtain a colloidal dispersion of precious metal-coated silver fine particles,
  A desalting / concentration step for obtaining a dispersion concentrate of the noble metal-coated silver fine particles by performing a desalting treatment for reducing the electrolyte concentration in the colloidal dispersion of the noble metal-coated silver fine particles and a concentration treatment for concentrating the colloidal dispersion;
  Solvent blending step of obtaining a coating solution for forming a transparent conductive layer by adding a solvent alone or a solvent containing conductive oxide fine particles or / and an inorganic binder to the dispersion concentrate of the noble metal-coated silver fine particles,
  It comprises each of these processes.
[0020]
  The invention according to claim 8 is
  Based on the manufacturing method of the coating liquid for forming a transparent conductive layer according to claim 6 or 7,
  In the precious metal-coated silver fine particle preparation step,Gold aloneThe colloidal dispersion of fine silver particles and the alkali metal so that the coating amount is set in the range of 5 to 100 parts by weight with respect to 100 parts by weight of silver.Gold salt solutionEach mixing ratio is adjusted.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail.
[0022]
  First, the present inventionMoneyIs chemically stable and has excellent weather resistance, chemical resistance, oxidation resistance, etc.MoneyIt is based on the idea that its chemical stability can be improved by coating the coating. Also,MoneySince it is applied as a coating layer on the surface of the silver fine particles, it does not impair the good conductivity of silver. The aboveMoneyInstead of coating the silver particles with silverMoneyA method of improving the properties such as the above-mentioned weather resistance can be considered by alloying with an alloy fine particle.MoneyBecause it is necessary to increase the concentration ofMoneyIs necessary and costly. In view of the above, in the present invention, as the metal fine particles in the transparent conductive layer forming coating solution,Gold aloneThe above-mentioned problems are solved by applying noble metal-coated silver fine particles coated with.
[0023]
  That is, on the surface of the silver fine particlesGold aloneCoating, the silver inside the precious metal coated silver fine particlesMoneyTherefore, weather resistance, chemical resistance, etc. are remarkably improved. For example, when a transparent conductive layer composed of silver fine particles and a binder matrix containing silicon oxide as a main component is immersed in 5% saline, chlorine ions in the saline and silver fine particles in the transparent conductive layer react with each other for less than 1 hour. Although it deteriorates significantly with time and even peeling of the film in the transparent conductive layer occurs,Gold aloneIn the case of a transparent conductive layer to which noble metal coated silver fine particles coated withMoneyDepending on the coating amount, the transparent conductive layer does not change at all even when immersed for 24 hours or more, and exhibits excellent weather resistance. Also,MoneySince no oxidation occurs in the air, the electrical resistance does not deteriorate due to oxidation, and the transparent conductive layer to which the noble metal-coated silver fine particles are applied is superior to the surface resistance of the transparent conductive layer to which the silver fine particles are applied.
[0024]
Here, the noble metal-coated silver fine particles in the present invention are required to have an average particle diameter of 1 to 100 nm (claim 1). When the thickness is less than 1 nm, it is difficult to produce the fine particles, and further, the particles are likely to aggregate in the coating liquid and are not practical. On the other hand, if the thickness exceeds 100 nm, the visible light transmittance of the formed transparent conductive layer becomes too low. Even if the film thickness is set thin and the visible light transmittance is increased, the surface resistance becomes too high. This is because it is not practical. In addition, the average particle diameter here has shown the average particle diameter of the microparticles | fine-particles observed with a transmission electron microscope (TEM).
[0025]
  Next, in the noble metal coated silver fine particles,Gold aloneThe coating amount is desirably set in the range of 5 to 100 parts by weight with respect to 100 parts by weight of silver (Claim 2), and preferably in the range of 10 to 50 parts by weight.Gold aloneIf the coating amount is less than 5 parts by weight, the protective effect of the coating may be weakened and the weather resistance may be slightly deteriorated. On the other hand, if it exceeds 100 parts by weight, the cost is difficult.
[0026]
For the purpose of improving the film transmittance in the transparent conductive layer to be formed, one or more kinds of conductive oxides selected from tin oxide, tin antimony oxide or indium tin oxide in the coating liquid for forming the transparent conductive layer are used. Fine particles may be added (claims 3 and 4). In this case, the compounding ratio of the noble metal coated silver fine particles and the conductive oxide fine particles in the transparent conductive layer to be formed is 1 to 200 parts by weight, preferably 10 to 10 parts by weight of the conductive oxide fine particles with respect to 100 parts by weight of the noble metal coated silver fine particles. It is good to set to the range of 100 weight part. When the blending amount of the conductive oxide fine particles is less than 1 part by weight, the effect of adding the conductive oxide fine particles is not seen, and conversely, when it exceeds 200 parts by weight, the resistance of the transparent conductive layer becomes too high and practical. Because it is not the target. Further, like the noble metal-coated silver fine particles, the average particle diameter of the conductive oxide fine particles is preferably about 1 to 100 nm.
[0027]
  Next, the coating liquid for forming a transparent conductive layer according to the present invention to which the noble metal-coated silver fine particles are applied can be produced by the following method. First, a colloidal dispersion of silver fine particles is prepared by a known method [for example, Carey-Lea method, Am. J. Sci., 37, 47 (1889), Am. J. Sci., 38 (1889)]. That is, a silver nitrate aqueous solution is mixed with an iron (II) sulfate aqueous solution and a sodium citrate aqueous solution and reacted. After the precipitate is filtered and washed, pure water is added to the colloidal dispersion of silver particles ( Ag: 0.1 to 10% by weight) is prepared. The method for preparing the colloidal dispersion of silver fine particles is arbitrary and not limited to this as long as silver fine particles having an average particle diameter of 1 to 100 nm are dispersed. A reducing agent is added to the resulting colloidal dispersion of silver fine particles, and an alkali metal is further added thereto.Gold salt solutionTo the surface of the silver fine particlesGold aloneTo obtain a colloidal dispersion of noble metal-coated silver fine particles (Claim 6). In this precious metal-coated silver fine particle preparation step, if necessary, a colloidal dispersion of silver fine particles, an alkali metalGold salt solutionA small amount of a dispersant may be added to each of at least one of the above. In addition, in the precious metal coated silver fine particle preparation step,Gold aloneThe coating reaction ofGold saltBy reductionMoneyWhen there is a large amount of fine silver particles already in the liquid,MoneyThis is because it progresses under conditions that are advantageous in terms of energy when it is grown on the surface of silver fine particles as nuclei rather than nucleating alone (uniform nucleation). Therefore,Gold saltBy reductionMoneyIs premised on the presence of a large amount of fine silver fine particles in the liquid,Gold salt solutionAnd the addition timing of the reducing agent, at leastGold salt solutionIt is preferable to adjust so that the said reducing agent is added earlier. That is, with a reducing agentGold salt solutionWhen added to a colloidal dispersion of silver fine particles in a mixed state,Gold salt solutionAt the stage of mixing with the reducing agentGold saltBy reductionMoneyHas occurred, andMoneyNucleates alone (uniform nucleation),Gold salt solutionEven if it is added to the colloidal dispersion of silver particles after mixingMoneyThis is because the coating reaction may not occur.
[0028]
  The reducing agent includes hydrazine (N₂H_Four), Sodium borohydride (NaBH)_FourBoron hydride compounds such as), formaldehyde, etc. can be used, but when added to a colloidal dispersion of silver fine particles, the silver ultrafine particles do not aggregate,Gold saltTheMoneyIt is arbitrary as long as it can be reduced, and is not limited thereto.
[0029]
  For example,Potassium goldate [KAu (OH) _Four ]The reduction reaction when reducing hydrazine with hydrazine or sodium borohydride is shown as follows, respectively.
[0030]
  KAu (OH)_Four+ 3 / 4N₂H_Four→ Au + KOH + 3H₂O + 3 / 4N₂↑
  KAu (OH)_Four+ 3 / 4NaBH_Four→ Au + KOH + 3 / 4NaOH
                                      + 3 / 4H_ThreeBO_Three+ 3 / 2H₂↑
  Here, when the sodium borohydride is used as the reducing agent, the concentration of the electrolyte generated by the reduction reaction increases as can be confirmed from the above reaction formula. The addition amount is limited, and there is an inconvenience that the silver concentration in the colloidal dispersion of silver fine particles to be used cannot be increased.
[0031]
On the other hand, when the hydrazine is used as a reducing agent, the electrolyte generated by the reduction reaction is small as can be confirmed from the above reaction formula, and is more suitable as a reducing agent.
[0032]
  still,MoneyAs a coating raw material,Salts other than alkali metal aurateFor example,Chloroauric acid (HAuCl _Four ) Or chloroaurate (NaAuCl) _Four , KAuCl _Four etc)Is used, the reduction reaction with hydrazine is shown as follows.
[0033]
  XAuCl_Four+ 3 / 4N₂H_Four→ Au + XCl + 3HCl + 3 / 4N₂↑
                                            (X = H, Na, K, etc.)
  When chloroauric acid is applied in this way,The above metal saltCompared with the case of using, not only the electrolyte concentration due to the reduction reaction is increased, but also chlorine ions are generated, which reacts with the silver fine particles to produce hardly soluble silver chloride. It is difficult to use as a raw material for forming a transparent conductive layer.
[0034]
  In the above method, without using a reducing agent such as hydrazine, silver andMoneyBy substitution reaction due to difference in ionization tendency ofMoneyIt is also possible to perform coating.
[0035]
  That is, the colloidal dispersion of silver fine particlesGold salt solutionBy adding directly, a colloidal dispersion of noble metal-coated silver fine particles can be obtained (Claim 7).
[0036]
  still,MoneyThe coating reaction of is shown as follows.
[0037]
      3Ag + Au³⁺→ 3Ag⁺+ Au
  The colloidal dispersion of the noble metal-coated silver fine particles obtained as described above can be used to lower the electrolyte concentration in the dispersion by a desalting method such as dialysis, electrodialysis, ion exchange, and ultrafiltration. preferable. This is because colloids generally aggregate in the electrolyte unless the electrolyte concentration is lowered, and this phenomenon is also known as the Schulze-Hardy law.
[0038]
For the same reason, conductive oxide fine particles selected from tin oxide, tin antimony oxide or indium tin oxide are added into the colloidal dispersion of the noble metal-coated silver fine particles or the coating liquid for forming a transparent conductive layer. When blended, it is desirable that these conductive oxide fine particles or dispersions thereof are sufficiently desalted.
[0039]
Next, the colloidal dispersion of the noble metal-coated silver fine particles subjected to the desalting treatment is concentrated to obtain a dispersion concentrated liquid of the noble metal-coated silver fine particles. The organic solvent containing the conductive oxide fine particles and / or the inorganic binder is added to adjust the components (fine particle concentration, water concentration, etc.) to obtain the coating liquid for forming a transparent conductive layer according to the present invention. In addition, when ultrafiltration is applied as a desalination treatment method, this ultrafiltration also acts as a concentration treatment as described below, and therefore, desalination treatment and concentration treatment can be performed simultaneously. is there. Therefore, for the desalting treatment and concentration treatment of the colloidal dispersion in which the precious metal-coated silver fine particles are dispersed, the order is arbitrarily set depending on the treatment method to be applied, and when ultrafiltration or the like is applied, simultaneous treatment is performed. Is also possible.
[0040]
  Here, in the coating liquid for forming a transparent conductive layer according to the present invention, on the surface of the silver fine particlesGold aloneThe basis for the coating is particle observation with a transmission electron microscope (TEM) and component analysis (EDX: energy dispersive X-ray analyzer).MoneyThat the particle size has hardly changed before and after coating, andMoneyDistribution of particles is uniform for each particle, and further by EXAFS (Extended X-ray Absorption Fine Structure) analysisMoneyIt is technically confirmed from the number of coordination.
[0042]
The concentration treatment of the colloidal dispersion of the noble metal-coated silver fine particles can be performed by a conventional method such as a vacuum evaporator or ultrafiltration. Moreover, the water concentration in the coating liquid for forming a transparent conductive layer is preferably 1 to 20% by weight. This is because if the amount exceeds 20% by weight, the transparent conductive layer forming coating solution may be easily repelled during drying after being coated on the transparent substrate due to the high surface tension of water.
[0043]
Note that the above problem of repelling can be solved by adding a surfactant to the coating liquid for forming the transparent conductive layer. However, there may be another problem that a coating defect is likely to occur due to the blending of the surfactant. Therefore, the water concentration in the coating liquid for forming a transparent conductive layer is preferably 1 to 20% by weight.
[0044]
Moreover, there is no restriction | limiting in particular as said organic solvent, According to the coating method and film forming conditions, it selects suitably. For example, alcohol solvents such as methanol, ethanol, isopropanol, butanol, benzyl alcohol, diacetone alcohol, ketone solvents such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), cyclohexanone, isophorone, propylene glycol methyl ether, Examples include glycol derivatives such as propylene glycol ethyl ether, dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), and the like, but are not limited thereto.
[0045]
Next, using the thus obtained coating liquid for forming a transparent conductive layer according to the present invention, a transparent substrate, noble metal-coated silver fine particles having an average particle diameter of 1 to 100 nm and a binder formed on the transparent substrate A transparent conductive base material, the main part of which is composed of a transparent conductive layer mainly composed of a matrix and a transparent two-layer film comprising a transparent coating layer formed thereon, can be obtained.
[0046]
  And in order to form the said transparent double layer film | membrane on a transparent substrate, this can be performed with the following method. That is, a coating liquid for forming a transparent conductive layer according to the present invention mainly comprising a solvent and noble metal-coated silver fine particles having an average particle diameter of 1 to 100 nm is spray-coated, spin-coated on a transparent substrate such as a glass substrate or a plastic substrate After applying by a method such as wire bar coating or doctor blade coating and drying as necessary, for example, a coating solution for forming a transparent coat layer mainly composed of silica sol or the like is overcoated by the above-described method. Next, after overcoating, for example, a heat treatment is performed at a temperature of about 50 to 250 ° C. to cure the overcoated coating liquid for forming a transparent coat layer to form the transparent two-layer film. In the heat treatment at about 50 to 250 ° C., the noble metal coated silver fine particles areMoneyHowever, in the case of silver fine particles, when the temperature exceeds 200 ° C., the surface resistance value increases due to oxidative diffusion and the film deteriorates.
[0047]
  Here, when the coating liquid for forming a transparent coating layer mainly composed of silica sol or the like is overcoated by the above-described method, the coating liquid for forming a transparent conductive layer mainly composed of a pre-coated solvent and noble metal coated silver fine particles is used. The gap between the formed noble metal-coated silver fine particle layers is impregnated with an overcoated silica sol solution (this silica sol solution becomes a binder matrix mainly composed of silicon oxide by the above heat treatment), thereby improving conductivity and increasing strength. Improvement and further improvement of weather resistance are achieved at the same time. Further, in the optical constant (n-ik) of the transparent conductive layer in which the noble metal-coated silver fine particles are dispersed in the binder matrix containing silicon oxide as a main component, the refractive index n is not so large but the extinction coefficient k is large. The reflectance of the transparent two-layer film can be greatly reduced by the transparent two-layer film structure of the transparent conductive layer and the transparent coat layer. As shown in FIG. 1, noble metal-coated silver fine particles coated with simple gold (Example 1) even when compared with the case where ITO fine particles (Comparative Example 2) and silver fine particles (Comparative Example 1) are applied. When is used, the reflectance is improved in the short wavelength region (380 to 500 nm) of visible light. In addition, the transmitted light profile of the transparent two-layer film is improved by coating the silver fine particles with a single gold substance in the short wavelength range of visible light as shown in FIG. For example, when the standard deviation of the transmittance of only a transparent two-layer film not including a transparent substrate at each wavelength of 5 nm in the visible light wavelength range (380 to 780 nm) is compared, silver fine particles (Comparative Example 1) are used. However, the silver fine particles are coated with a noble metal (Example 1).-7, Reference Examples 1-4) And a small value of about 2-3%, and a very flat transmission profile is obtained. The reason why the reflection and transmission characteristics of these transparent two-layer films are improved is not yet clear.MoneyIt is considered that the surface plasmon of the metal fine particles changes due to the coating.
[0048]
Here, as the silica sol, a polymer obtained by adding water or an acid catalyst to an orthoalkyl silicate and hydrolyzing it to cause dehydration condensation polymerization, or a commercial product that has already undergone hydrolysis condensation polymerization to a tetramer to a pentamer. A polymer obtained by further hydrolyzing and dehydrating polycondensation can be used for the alkyl silicate solution. As dehydration condensation polymerization proceeds, the solution viscosity increases and eventually solidifies. Therefore, the degree of dehydration condensation polymerization is less than the upper limit viscosity that can be applied on a transparent substrate such as a glass substrate or a plastic substrate. Adjust to. However, the degree of dehydration condensation polymerization is not particularly specified as long as it is a level equal to or lower than the above upper limit viscosity, but in view of film strength, weather resistance and the like, a weight average molecular weight of about 500 to 3000 is preferable. The alkyl silicate partially hydrolyzed polymer almost completes the dehydration condensation polymerization reaction when the transparent two-layer film is heated and fired, and becomes a hard silicate film (a film containing silicon oxide as a main component). It is also possible to change the reflectance of the transparent two-layer film by adding magnesium fluoride fine particles, alumina sol, titania sol, zirconia sol or the like to the silica sol to adjust the refractive index of the transparent coating layer.
[0049]
Further, in addition to the solvent and the noble metal-coated silver fine particles having an average particle diameter of 1 to 100 nm dispersed in the solvent, a silica sol solution as an inorganic binder component constituting the binder matrix of the transparent conductive layer is blended to thereby add the transparent conductive material according to the present invention. You may comprise the coating liquid for layer formation (Claim 5-Claim 7). In this case as well, by applying a coating solution for forming a transparent conductive layer containing a silica sol solution and drying it as necessary, the coating solution for forming a transparent coating layer is overcoated by the above-described method. A transparent two-layer film is obtained. For the same reason as when conductive oxide fine particles are blended in the transparent conductive layer forming coating solution, the silica sol solution blended in the transparent conductive layer forming coating solution is also sufficiently desalted. It is desirable to keep it.
[0050]
As described above, the transparent conductive substrate having a transparent conductive layer formed by applying the coating liquid for forming a transparent conductive layer according to the present invention has a better antireflection effect and transmitted light profile than conventional ones. For example, the cathode ray tube (CRT), plasma display panel (PDP), fluorescent display tube (VFD), field emission display (FED), electroluminescence It can be used for a front plate or the like in a display device such as a display (ELD) or a liquid crystal display (LCD).
[0051]
【Example】
Examples of the present invention will be specifically described below, but the present invention is not limited to these examples. Further, “%” in the text indicates “% by weight” excluding (%) of transmittance, reflectance, and haze value, and “part” indicates “weight part”.
[0052]
[Example 1]
A colloidal dispersion of silver fine particles was prepared by the aforementioned Carey-Lea method. Specifically, after adding a mixed solution of 39 g of 23% iron (II) sulfate solution and 48 g of 37.5% sodium citrate aqueous solution to 33 g of 9% silver nitrate aqueous solution, the precipitate was filtered and washed, and then purified water Was added to prepare a colloidal dispersion of silver fine particles (Ag: 0.45%). While adding 0.5 g of a 1% hydrazine aqueous solution to 15 g of the colloidal dispersion of silver fine particles and stirring, potassium metalate [KAu (OH)_FourA mixed solution of 15 g of an aqueous solution (Au: 0.1%) and 0.3 g of a 2% polymer dispersant aqueous solution was added to obtain a colloidal dispersion of noble metal-coated silver fine particles coated with simple gold.
[0053]
This noble metal-coated colloidal dispersion of silver fine particles is desalted with an ion exchange resin (trade name Diaion SK1B, SA20AP manufactured by Mitsubishi Chemical Corporation), and then concentrated by ultrafiltration to ethanol (EA), diacetone alcohol ( DAA) and a transparent conductive layer forming coating solution according to Example 1 containing noble metal-coated silver fine particles (Ag: 0.217%, Au: 0.057%, water: 11.8%, EA: 82) 9%, DAA: 5.0%). As a result of observing this coating liquid for forming a transparent conductive layer with a transmission electron microscope, the average particle diameter of the noble metal-coated silver fine particles was 7.2 nm.
[0054]
Next, the transparent conductive layer forming coating solution according to Example 1 containing noble metal-coated silver fine particles was spin-coated (130 rpm, 3 mm thick soda lime glass) on a glass substrate heated to 40 ° C. 60 seconds), then, the silica sol solution is spin-coated (130 rpm, 60 seconds), and further cured at 180 ° C. for 20 minutes to contain a transparent conductive layer containing noble metal-coated silver fine particles, and silicon oxide as a main component. A glass substrate with a transparent two-layer film composed of a transparent coating layer made of a silicate film, that is, a transparent conductive substrate according to Example 1 was obtained.
[0055]
Here, the silica sol solution is composed of 19.6 parts of methyl silicate 51 (trade name, manufactured by Colcoat Co.), 57.8 parts of ethanol, 7.9 parts of 1% nitric acid aqueous solution, and 14.7 parts of pure water.₂(Silicon oxide) A solid content of 10% is prepared, and finally, SiO₂It is obtained by diluting with a mixture of isopropyl alcohol (IPA) and n-butanol (NBA) (IPA / NBA = 3/1) so that the solid content concentration becomes 0.7%.
[0056]
The film properties (surface resistance, visible light transmittance, transmittance standard deviation, haze value, bottom reflectance / bottom wavelength) of the transparent two-layer film formed on the glass substrate are shown in Table 1 below. The bottom reflectance means a minimum reflectance in the reflection profile of the transparent conductive substrate, and the bottom wavelength means a wavelength at which the reflectance is a minimum. Further, the reflection profile of the transparent conductive substrate according to Example 1 is shown in FIGS. 1 and 3, and the transmission profile is shown in FIGS.
[0057]
In Table 1, the transmittance of only the transparent two-layer film not including the transparent substrate (glass substrate) at each wavelength of 5 nm in the visible light wavelength range (380 to 780 nm) is obtained as follows. That is,
Transmittance (%) of transparent two-layer film only without transparent substrate
= [(Transmittance measured for each transparent substrate) / (Transparency of transparent substrate)] × 100
Here, in this specification, unless otherwise specified, the transmittance is a value measured for each transparent substrate (that is, the transparent conductive substrate including the transparent substrate means the transparent conductive substrate). ing.
[0058]
The surface resistance of the transparent two-layer film was measured using a surface resistance meter Loresta AP (MCP-T400) manufactured by Mitsubishi Chemical Corporation. The haze value and visible light transmittance were measured for each transparent substrate using a haze meter (HR-200) manufactured by Murakami Color Research Laboratory. The reflectance and the reflection / transmission profile were measured using a spectrophotometer (U-4000) manufactured by Hitachi, Ltd. The particle diameter of the noble metal-coated silver fine particles is evaluated with a transmission electron microscope made by JEOL.
[0059]
[Example 2]
Using a colloidal dispersion of silver fine particles prepared by the same method as in Example 1, and using a 1.5% hydrazine aqueous solution and a potassium oxalate aqueous solution (Au: 0.15%), the same as in Example 1 The transparent conductive layer forming coating solution according to Example 2 in which noble metal-coated silver fine particles having an average particle size of 6.3 nm were dispersed by the treatment (Ag: 0.221%, Au: 0.079%, water: 5.0) %, EA: 89.7%, DAA: 5.0%).
[0060]
And this coating liquid for forming a transparent conductive layer was used, and the silica sol liquid SiO₂(Silicon oxide) A transparent conductive layer containing noble metal-coated silver fine particles and a silicate film containing silicon oxide as a main component, except that the solid content concentration was diluted to 0.65%. A transparent conductive layer according to Example 2 was obtained, that is, a glass substrate with a transparent two-layer film composed of a transparent coating layer comprising:
[0061]
The film properties of the transparent two-layer film formed on the glass substrate are shown in Table 1 below. Moreover, the reflection profile of the transparent conductive base material which concerns on Example 2 is shown in FIG. 5, and a transmission profile is shown in FIG.
[0062]
[Example 3]
Using a colloidal dispersion of silver fine particles prepared by the same method as in Example 1, and using a 0.5% hydrazine aqueous solution and a potassium oxalate aqueous solution (Au: 0.05%), the same as in Example 1 The transparent conductive layer forming coating liquid according to Example 3 (Ag: 0.24%, Au: 0.028%, water: 3.7) in which precious metal-coated silver fine particles having an average particle diameter of 6.8 nm were dispersed by the treatment. %, EA: 91.0%, DAA: 5.0%).
[0063]
And this coating liquid for forming a transparent conductive layer was used, and the silica sol liquid SiO₂(Silicon oxide) A transparent conductive layer containing noble metal-coated silver fine particles and a silicate film containing silicon oxide as a main component, except that the solid content concentration was diluted to 0.65%. A transparent conductive layer according to Example 3 was obtained, that is, a glass substrate with a transparent two-layer film composed of a transparent coating layer comprising:
[0064]
The film properties of the transparent two-layer film formed on the glass substrate are shown in Table 1 below.
[0065]
[Example 4]
Using a colloidal dispersion of silver fine particles prepared in the same manner as in Example 1, 15 g of an aqueous potassium metalate solution (Au: 0.05%) was added while stirring without adding a hydrazine aqueous solution as a reducing agent. A colloidal dispersion of noble metal-coated silver fine particles is obtained by a substitution reaction of gold and silver, and the same treatment as in Example 1 is performed to disperse noble metal-coated silver fine particles having an average particle diameter of 6.5 nm. A coating liquid for forming a conductive layer (Ag: 0.245%, Au: 0.025%, water: 7.6%, EA: 87.1%, DAA: 5.0%) was obtained.
[0066]
A transparent coating layer comprising a transparent conductive layer containing noble metal-coated silver fine particles and a silicate film containing silicon oxide as a main component, except that this coating solution for forming a transparent conductive layer was used. A glass substrate with a transparent two-layer film constituted by the above, that is, a transparent conductive substrate according to Example 4 was obtained.
[0067]
The film properties of the transparent two-layer film formed on the glass substrate are shown in Table 1 below.
[0068]
[Example 5]
Using a colloidal dispersion of silver fine particles prepared by the same method as in Example 1, and using 0.4 g of 1% hydrazine aqueous solution and potassium oxalate aqueous solution (Au: 0.075%), an average particle size of 7. A solution in which 1 nm of noble metal-coated silver fine particles was dispersed was obtained.
[0069]
Next, this solution is obtained by sufficiently desalting by using indium tin oxide (ITO) fine particles (manufactured by Sumitomo Metal Mining Co., Ltd., trade name SUFP-HX) having an average particle size of 0.03 μm and ion exchange. The ITO dispersion liquid was added, and finally the noble metal-coated silver fine particles and ITO fine particles were dispersed, and the transparent conductive layer forming coating liquid according to Example 5 (Ag: 0.294%, Au: 0.049%, ITO: 0.1%, water: 9.7%, EA: 84.95%, DAA: 4.9%).
[0070]
Then, using this transparent conductive layer forming coating solution, and using a silica sol solution having a weight average molecular weight of 1920, SiO 2₂(Silicon oxide) Using a glass substrate diluted to a solid content concentration of 0.8% and heated to 35 ° C., the transparent conductive layer forming coating solution and the silica sol solution were used at 150 rpm for 60 seconds. A transparent conductive layer containing noble metal coated silver fine particles and ITO fine particles, and a silicate film containing silicon oxide as a main component except that spin coating and curing at 210 ° C. for 20 minutes were conducted in the same manner as in Example 1. A glass substrate with a transparent two-layer film composed of a transparent coating layer, that is, a transparent conductive substrate according to Example 5 was obtained.
[0071]
The film properties of the transparent two-layer film formed on the glass substrate are shown in Table 1 below. Moreover, the reflection profile of the manufactured transparent conductive substrate according to Example 5 is shown in FIG. 7, and the transmission profile is shown in FIG.
[0072]
[Example 6]
Using a colloidal dispersion of silver fine particles prepared by the same method as in Example 1, and using 0.4 g of 1% hydrazine aqueous solution and potassium oxalate aqueous solution (Au: 0.075%), an average particle size of 7. A solution in which 1 nm of noble metal-coated silver fine particles was dispersed was obtained.
[0073]
Next, this solution was obtained by sufficiently desalting by ion exchange using antimony tin oxide (ATO) fine particles (Ishihara Sangyo Co., Ltd., trade name SN-100P) having an average particle diameter of 0.01 μm. The transparent conductive layer forming coating solution (Ag: 0.29%, Au: 0.048%, ATO: 0) according to Example 6 in which the ATO dispersion was added and finally the noble metal-coated silver fine particles and the ATO fine particles were dispersed. 174%, water: 11.0%, EA: 83.58, DAA: 4.9%).
[0074]
Then, using this transparent conductive layer forming coating solution, and using a silica sol solution having a weight average molecular weight of 1920, SiO 2₂(Silicon oxide) Using a glass substrate diluted to a solid content concentration of 0.8% and heated to 35 ° C., the transparent conductive layer forming coating solution and the silica sol solution were used at 150 rpm for 60 seconds. Except for spin coating and curing at 210 ° C. for 20 minutes, the same procedure as in Example 1 was performed. From a transparent conductive layer containing noble metal-coated silver fine particles and ATO fine particles, and a silicate film mainly composed of silicon oxide A glass substrate with a transparent two-layer film composed of the transparent coating layer thus formed, that is, a transparent conductive substrate according to Example 6 was obtained.
[0075]
The film properties of the transparent two-layer film formed on the glass substrate are shown in Table 1 below. Moreover, the reflection profile of the manufactured transparent conductive substrate according to Example 6 is shown in FIG. 9, and the transmission profile is shown in FIG.
[0076]
[Example 7]
Using a colloidal dispersion of silver fine particles prepared in the same manner as in Example 1, and using 0.4 g of a 1% hydrazine aqueous solution and a potassium gold acid aqueous solution (Au: 0.075%), noble metal-coated silver fine particles A dispersion concentrated liquid was obtained, and a solution containing tetramethyl silicate tetramer (trade name: methyl silicate 51, manufactured by Colcoat Co.) as an inorganic binder was added thereto to disperse noble metal coated silver fine particles having an average particle diameter of 7.0 nm. The transparent conductive layer forming coating solution according to Example 7 (Ag: 0.29%, Au: 0.052%, SiO 2₂: 0.02%, water: 8.78%, EA: 85.85%, DAA: 5.0%).
[0077]
Then, using this transparent conductive layer forming coating solution, and using a silica sol solution having a weight average molecular weight of 2460, SiO 2₂(Silicon oxide) Using a glass substrate diluted to a solid content concentration of 0.7% and heated to 35 ° C., the transparent conductive layer forming coating solution and the silica sol solution are used at 150 rpm for 60 seconds. A transparent coat comprising a transparent conductive layer containing noble metal-coated silver fine particles and a silicate film containing silicon oxide as a main component, except that spin coating and curing at 210 ° C. for 20 minutes are performed. A glass substrate with a transparent two-layer film composed of layers, that is, a transparent conductive substrate according to Example 7 was obtained.
[0078]
The film properties of the transparent two-layer film formed on the glass substrate are shown in Table 1 below.
[0079]
  [Reference example 1]
  After adding a mixed solution of 39 g of 23% iron (II) sulfate solution and 48 g of 37.5% sodium citrate aqueous solution to 33 g of 9% silver nitrate aqueous solution, the precipitate was filtered and washed, and then pure water was added to add silver. A colloidal dispersion of fine particles (Ag: 0.49%) was prepared. To 240 g of the colloidal dispersion of silver fine particles, hydrazine monohydrate (N₂H_Four・ H₂While adding 5 g of 1% aqueous solution of O) and stirring, potassium platinum (IV) ate [K₂Pt (OH)₆] 200 g of an aqueous solution (Pt: 0.06%) was added to obtain a colloidal dispersion of noble metal-coated silver fine particles coated with platinum alone.
[0080]
  After concentrating the colloidal dispersion of the noble metal-coated silver fine particles by ultrafiltration, adding pure water to the concentrate and concentrating it again by ultrafiltration, the desalted concentrate obtained by repeating the step of adding ethanol ( EA), diacetone alcohol (DAA),Reference example 1The transparent conductive layer forming coating solution (Ag: 0.245%, Pt: 0.025%, water: 7.48%, EA: 87.25%, DAA: 5.0%) was obtained. As a result of observing this coating liquid for forming a transparent conductive layer with a transmission electron microscope, the average particle diameter of the noble metal-coated silver fine particles was 9.2 nm.
[0081]
  Next, this coating solution for forming a transparent conductive layer was spin-coated (130 rpm, 60 seconds) on a glass substrate (3 mm thick soda lime glass) heated to 40 ° C., and then a silica sol solution was added. Spin coating (130 rpm, 60 seconds), further curing at 180 ° C. for 20 minutes, and composed of a transparent conductive layer containing noble metal coated silver fine particles and a transparent coating layer composed of a silicate film mainly composed of silicon oxide A glass substrate with a transparent two-layer film, that is,Reference example 1A transparent conductive substrate was obtained.
[0082]
Here, the silica sol solution is composed of 19.6 parts of methyl silicate 51 (trade name, manufactured by Colcoat Co.), 57.8 parts of ethanol, 7.9 parts of 1% nitric acid aqueous solution, and 14.7 parts of pure water.₂(Silicon oxide) A solid content of 10% is prepared, and finally, SiO₂It is obtained by diluting with a mixture of isopropyl alcohol (IPA) and n-butanol (NBA) (IPA / NBA = 3/1) so that the solid content concentration becomes 0.65%.
[0083]
  Table 1 below shows the film characteristics of the transparent two-layer film formed on the glass substrate. Also manufacturedReference example 1The reflection profile of the transparent conductive substrate according to FIG. 11 is shown in FIGS. 11 and 13, and the transmission profile is shown in FIGS.
[0084]
  [Reference example 2]
  Reference example 1A colloidal dispersion of silver fine particles prepared by the same method as above, and hydrazine monohydrate (N₂H_Four・ H₂6.3 g of a 1% aqueous solution of O) and a gold salt [KAu (OH)_Four] 121 g of aqueous solution (Au: 0.098%) and potassium platinumate [K₂Pt (OH)₆] Using a mixed solution of 121 g of an aqueous solution (Pt: 0.065%),Reference example 1The noble metal-coated silver fine particles having an average particle diameter of 11.7 nm coated with a composite of gold and platinum were dispersed in the same manner as described above.Reference example 2Transparent conductive layer forming coating solution (Ag: 0.26%, Au: 0.03%, Pt: 0.02%, water: 7.48%, EA: 87.2%, DAA: 5.0 %).
[0085]
  And, except using this transparent conductive layer forming coating solution,Reference example 1A glass substrate with a transparent two-layer film composed of a transparent conductive layer containing noble metal-coated silver fine particles and a transparent coat layer composed of a silicate film mainly composed of silicon oxide,Reference example 2A transparent conductive substrate was obtained.
[0086]
  The film properties of the transparent two-layer film formed on the glass substrate are shown in Table 1 below. Also manufacturedReference example 2FIG. 15 shows the reflection profile of the transparent conductive substrate according to the above, and FIG. 16 shows the transmission profile.
[0087]
  [Reference example 3]
  Reference example 1Using a colloidal dispersion of silver fine particles prepared in the same manner as described above, without adding the hydrazine aqueous solution as a reducing agent, the potassium platinate [K₂Pt (OH)₆] 203 g of aqueous solution (Pt: 0.064%) was added, and a colloidal dispersion of precious metal-coated silver fine particles coated with platinum was obtained by a platinum-silver substitution reaction.Reference example 1In the same manner as above, noble metal-coated silver fine particles having an average particle diameter of 9.2 nm were dispersed.Reference example 3The transparent conductive layer forming coating solution (Ag: 0.24%, Pt: 0.025%, water: 9.2%, EA: 85.53%, DAA: 5.0%) was obtained.
[0088]
  And, except using this transparent conductive layer forming coating solution,Reference example 1A glass substrate with a transparent two-layer film composed of a transparent conductive layer containing noble metal-coated silver fine particles and a transparent coat layer composed of a silicate film mainly composed of silicon oxide,Reference example 3A transparent conductive substrate was obtained.
[0089]
The film properties of the transparent two-layer film formed on the glass substrate are shown in Table 1 below.
[0090]
  [Reference example 4]
  Reference example 1Using a colloidal dispersion of silver fine particles (Ag: 0.49%) prepared in the same manner as in Example 1, potassium platinate [K₂Pt (OH)₆] 203 g of an aqueous solution (Pt: 0.064%) was added, and a solution in which noble metal-coated silver fine particles having an average particle diameter of 9.2 nm coated with platinum alone was dispersed was obtained by a platinum-silver substitution reaction.
[0091]
  Next, this solution is obtained by sufficiently desalting by using indium tin oxide (ITO) fine particles (manufactured by Sumitomo Metal Mining Co., Ltd., trade name SUFP-HX) having an average particle size of 0.03 μm and ion exchange. ITO dispersion liquid was added and finally the above precious metal coated silver fine particles and ITO fine particles were dispersed.Reference example 4The transparent conductive layer forming coating solution (Ag: 0.312%, Pt: 0.0325%, ITO: 0.12%, water: 12.3%, EA: 87.23%) was obtained.
[0092]
  Then, using this transparent conductive layer forming coating solution, and using a silica sol solution having a weight average molecular weight of 1920, SiO 2₂(Silicon oxide) Using a glass substrate diluted to a solid content concentration of 0.8% and heated to 35 ° C., the transparent conductive layer forming coating solution and the silica sol solution were used at 150 rpm for 60 seconds. Except for spin coating and curing at 210 ° C. for 20 minutes,Reference example 1A glass substrate with a transparent two-layer film composed of a transparent conductive layer containing noble metal-coated silver fine particles and ITO fine particles and a transparent coat layer composed of a silicate film mainly composed of silicon oxide,Reference example 4A transparent conductive substrate was obtained.
[0093]
  The film properties of the transparent two-layer film formed on the glass substrate are shown in Table 1 below. Also manufacturedReference example 4FIG. 17 shows a reflection profile and FIG. 18 shows a transmission profile of the transparent conductive substrate according to the present invention.
[0094]
[Comparative Example 1]
A coating liquid for forming a transparent conductive layer according to Comparative Example 1 in which silver fine particles having an average particle diameter of 6.9 nm were dispersed without using a colloidal dispersion of silver fine particles prepared by the same method as in Example 1 and gold coating ( Ag: 0.3%, water: 4.0%, EA: 90.7%, DAA: 5.0%).
[0095]
Then, except that this coating solution for forming a transparent conductive layer was used, the same procedure as in Example 1 was performed, and a transparent conductive layer containing silver fine particles and a transparent coat layer made of a silicate film containing silicon oxide as a main component were used. A configured glass substrate with a transparent two-layer film, that is, a transparent conductive substrate according to Comparative Example 1 was obtained.
[0096]
The film properties of the transparent two-layer film formed on the glass substrate are shown in Table 1 below. Moreover, the reflection profile of the manufactured transparent conductive substrate according to Comparative Example 1 is shown in FIGS. 1 and 11, and the transmission profile is shown in FIGS.
[0097]
[Comparative Example 2]
A coating solution for forming a transparent conductive layer according to Comparative Example 2 in which ITO fine particles having an average particle diameter of 30 nm were dispersed in a solvent (Sumitomo Metal Mining Co., Ltd., trade name: SDA-104, ITO: 2%) was heated to 40 ° C. After spin coating (150 rpm, 60 seconds) on a glass substrate (3 mm thick soda lime glass), SiO,₂(Silicon oxide) A transparent conductive layer containing ITO fine particles by spin-coating (150 rpm, 60 seconds) a silica sol solution diluted to a solid content concentration of 1.0% and further curing at 180 ° C. for 30 minutes. Thus, a glass substrate with a transparent two-layer film composed of a silicate film composed mainly of silicon oxide and a transparent conductive substrate according to Comparative Example 2 was obtained.
[0098]
Table 1 below shows the film characteristics of the transparent two-layer film formed on the glass substrate. Moreover, the reflection profile of the transparent conductive base material which concerns on the manufactured comparative example 2 is shown in FIG.
[0099]
[Table 1]

[0100]
  "Weather resistance test"
  Example 1-7, Reference Examples 1-4The transparent conductive base material according to the present invention and the transparent conductive base material according to Comparative Example 1 are immersed in 5% saline, and the surface resistance value of the transparent two-layer film provided on the transparent substrate (glass substrate), the appearance of the film I investigated. The results are shown in Table 2 below.
[0101]
[Table 2]

[0102]
  "Evaluation"
(1) As is clear from the results shown in Table 1,Examples 1-7, Reference Examples 1-4It is confirmed that the surface resistance (Ω / □) and the standard deviation value of the transmittance of the transparent two-layer film according to the present invention are remarkably improved as compared with the values of the transparent two-layer film according to each comparative example. In addition, the first embodiment shown in FIGS. 2 and 12 andReference example 1As is clear from the comparison of the transmission profile of the transparent conductive substrate according to Example 1 and the transmission profile of the transparent conductive substrate according to Comparative Example 1, Example 1 andReference example 1It is also confirmed that a very flat transmission profile is obtained with the transparent conductive substrate.
  Further, as is apparent from the reflection profiles of FIGS. 1 and 11, Example 1 andReference example 1It is confirmed that the transparent conductive base material according to the present invention has improved reflection characteristics in the visible light wavelength region.
(2) Also, as is clear from the results shown in Table 2, compared to the transparent two-layer film according to Comparative Example 1.Examples 1-7, Reference Examples 1-4It is confirmed that the weather resistance of the transparent two-layer film according to the present invention is remarkably improved.
(3) Next, when the visible light transmittances of the transparent conductive substrates according to Examples 1 to 7 in which the noble metal-coated silver fine particles coated with simple gold are applied are confirmed from Table 1. The visible light transmittance of Example 5 containing ITO and Example 6 containing ATO is higher than that of the other examples.
[0103]
  On the other hand, precious metal coated silver fine particles coated with platinum alone or gold and platinum composites are applied.Reference Examples 1-4When the surface resistance of the transparent conductive substrate according to the present invention was compared, ITO was included as confirmed from Table 1.Reference example 4The surface resistance of each has the smallest value, and the visible light transmittance is substantially the same value. That is,Reference example 4so,Reference Examples 1-3When the thickness of the transparent conductive layer is set to be substantially the same as the surface resistance value of the transparent conductive layer, the visible light transmittance of the transparent conductive layer isReference Examples 1-3It shows that it can be higher.
[0104]
  From these, it is confirmed that when conductive oxide fine particles such as ITO and ATO are included in the transparent conductive layer, the film transmittance in the transparent conductive layer can be improved.
(4) In addition, Example 1-7, Reference Examples 1-4In the present invention, noble metal-coated silver fine particles are prepared by applying potassium goldate and potassium platinumate as the goldate and platinumate, but instead of these potassium metallate and potassium platinumate, sodium metalate and Experiments using sodium platinate have also been conducted.
[0105]
  Example 1 of the noble metal-coated silver fine particles obtained by applying sodium metallate and sodium platinumate-7, Reference Examples 1-4The same evaluation test is performed, and it is confirmed that the same evaluation can be obtained.
[0106]
【The invention's effect】
  According to the coating liquid for forming a transparent conductive layer according to the inventions of claims 1 to 5,
  Solvent, and dispersed in the solvent and on the surfaceGold aloneAs a main component, noble metal-coated silver fine particles with an average particle diameter of 1 to 100 nm coated with a coating material have a better antireflection function and electric field compared to a transparent conductive layer to which a conventional coating liquid for forming a transparent conductive layer is applied. It has an effect of forming a transparent conductive layer having a shielding function and having a transmitted light profile in the visible light region and good weather resistance.
[0107]
Moreover, according to the manufacturing method of the coating liquid for transparent conductive layer formation concerning the invention of Claims 6-8,
The transparent conductive layer forming coating liquid according to the present invention has an effect that can be easily produced at low cost.
[Brief description of the drawings]
FIG. 1 is a graph showing reflection profiles of transparent conductive substrates according to Example 1 and Comparative Examples 1 and 2. FIG.
2 is a graph showing transmission profiles of transparent conductive substrates according to Example 1 and Comparative Example 1. FIG.
3 is a graph showing a reflection profile of a transparent conductive substrate according to Example 1. FIG.
4 is a graph showing a transmission profile of a transparent conductive base material according to Example 1 and a glass substrate which is a constituent member of the base material. FIG.
5 is a graph showing a reflection profile of a transparent conductive substrate according to Example 2. FIG.
6 is a graph showing a transmission profile of a transparent conductive base material according to Example 2 and a glass substrate which is a constituent member of the base material. FIG.
7 is a graph showing a reflection profile of a transparent conductive substrate according to Example 5. FIG.
FIG. 8 is a graph showing a transmission profile of a transparent conductive base material according to Example 5 and a glass substrate which is a constituent member of the base material.
9 is a graph showing a reflection profile of a transparent conductive substrate according to Example 6. FIG.
FIG. 10 is a graph showing a transmission profile of a transparent conductive base material according to Example 6 and a glass substrate which is a constituent member of the base material.
FIG. 11Reference example 1The graph which shows the reflection profile of the transparent conductive base material which concerns on Comparative Examples 1-2.
FIG.Reference example 1FIG. 5 is a graph showing a transmission profile of a transparent conductive substrate according to Comparative Example 1.
FIG. 13Reference example 1The graph which shows the reflection profile of the transparent conductive base material which concerns on.
FIG. 14Reference example 1The graph which shows the permeation | transmission profile of the transparent conductive base material which concerns on, and the glass substrate which is a structural member of this base material.
FIG. 15Reference example 2The graph which shows the reflection profile of the transparent conductive base material which concerns on.
FIG. 16Reference example 2The graph which shows the permeation | transmission profile of the transparent conductive base material which concerns on, and the glass substrate which is a structural member of this base material.
FIG. 17Reference example 4The graph which shows the reflection profile of the transparent conductive base material which concerns on.
FIG. 18Reference example 4The graph which shows the permeation | transmission profile of the transparent conductive base material which concerns on, and the glass substrate which is a structural member of this base material.

Claims (8)

In a transparent conductive layer forming coating solution for forming the transparent conductive layer of the transparent conductive substrate comprising a transparent substrate and a transparent two-layer film comprising a transparent conductive layer and a transparent coat layer sequentially formed on the transparent substrate . ,
A coating liquid for forming a transparent conductive layer, comprising a solvent and noble metal-coated silver fine particles having an average particle diameter of 1 to 100 nm dispersed in the solvent and coated with simple gold on the surface of the silver fine particles. The coating solution for forming a transparent conductive layer according to claim 1, wherein the coating amount of gold alone in the noble metal-coated silver fine particles is set in a range of 5 to 100 parts by weight with respect to 100 parts by weight of silver.   The coating liquid for forming a transparent conductive layer according to claim 1 or 2, wherein conductive oxide fine particles are contained.   4. The coating liquid for forming a transparent conductive layer according to claim 3, wherein the conductive oxide fine particles are one or more fine particles selected from tin oxide, tin antimony oxide or indium tin oxide.   The coating liquid for forming a transparent conductive layer according to any one of claims 1 to 4, wherein an inorganic binder is contained. In the manufacturing method of the coating liquid for transparent conductive layer formation of Claim 1, 3 or 5,
Step of preparing noble metal coated silver fine particles to obtain a colloidal dispersion of noble metal coated silver fine particles by adding a reducing agent and an alkali metal metallate solution to a colloidal dispersion of silver fine particles and coating the surface of the silver fine particles with a simple substance of gold ,
A desalting / concentration step for obtaining a dispersion concentrate of the noble metal-coated silver fine particles by performing a desalting treatment for reducing the electrolyte concentration in the colloidal dispersion of the noble metal-coated silver fine particles and a concentration treatment for concentrating the colloidal dispersion;
Solvent blending step of obtaining a coating solution for forming a transparent conductive layer by adding a solvent alone or a solvent containing conductive oxide fine particles or / and an inorganic binder to the dispersion concentrate of the noble metal-coated silver fine particles,
The manufacturing method of the coating liquid for transparent conductive layer formation characterized by comprising each process of these. In the manufacturing method of the coating liquid for transparent conductive layer formation of Claim 1, 3 or 5,
Adding gold salt solution of an alkali metal in the colloidal dispersion of fine silver particles, silver, by substitution reaction with difference in ionization tendency of the metal coated with gold alone on the surface of the silver particles, colloidal noble metal-coated silver microparticles A precious metal-coated silver fine particle preparation step for obtaining a dispersion;
A desalting / concentration step for obtaining a dispersion concentrate of the noble metal-coated silver fine particles by performing a desalting treatment for reducing the electrolyte concentration in the colloidal dispersion of the noble metal-coated silver fine particles and a concentration treatment for concentrating the colloidal dispersion;
Solvent blending step of obtaining a coating solution for forming a transparent conductive layer by adding a solvent alone or a solvent containing conductive oxide fine particles or / and an inorganic binder to the dispersion concentrate of the noble metal-coated silver fine particles,
The manufacturing method of the coating liquid for transparent conductive layer formation characterized by comprising each process of these. In the precious metal-coated silver fine particle preparation step, the colloidal dispersion of silver fine particles and the alkali metal so that the coating amount of the gold simple substance in the precious metal-coated silver fine particles is set in the range of 5 to 100 parts by weight with respect to 100 parts by weight of silver. The method for producing a coating liquid for forming a transparent conductive layer according to claim 6, wherein the blending ratio of each of the gold salt solutions is adjusted.

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