JP2004303628A - Metal-clad metallic particle, its manufacturing method, transparent conductive film forming paint, conductive binding material, and transparent conductive film and display using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive metal-clad metallic particle having substantially improved transparency, conductivity, antistatic property, electromagnetic wave shielding performance, salt water resistance, acid resistance, oxidation resistance, and environment resistance such as ultraviolet resistance, a method for manufacturing it, transparent conductive film forming paint containing it, a conductive binding material, and a transparent conductive film and a display using it. <P>SOLUTION: In this metal-clad metallic particle, a cover layer 2 comprising a metal (A) the standard electrode potential of which is nobler than that of the metallic particle 1 is formed on a part of the surface of the metallic particle 1, and a cover layer 3 comprising a metal (B) the standard electrode potential of which is nobler than that of the metallic particle 1 and is baser than that of the metal (A) is formed on the surface of the metallic particle 1 excluding the cover layer 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００９５】
表１の結果によれば、実施例１は、核となるＡｇ微粒子の表面に、このＡｇよりも標準電極電位の貴なＡｕの被膜を形成し、その後、標準電極電位がＡｇよりも貴でありかつＡｕよりも卑なＰｄの被膜を形成したので、良好な透明性と導電性を有し、さらにこの透明性と導電性が塩酸（ＨＣｌ）の環境下、過酸化水素水（Ｈ_２Ｏ_２）の環境下でもほとんど変化しないことから、透明性、導電性、帯電防止性等に優れているばかりでなく、耐ＨＣｌ性、耐Ｈ_２Ｏ_２性等の耐環境性に優れていることが確認された。
【００９６】
一方、比較例１、２、４では、Ａｇ微粒子の表面に１種類の金属のみを析出させて被膜を形成したものであるから、初期の透明性、導電性については実施例１と大差はないものの、塩酸（ＨＣｌ）の環境下、過酸化水素水（Ｈ_２Ｏ_２）の環境下におくと大幅に透明性、導電性が悪化した。
また、比較例３では、Ａｇ微粒子の表面に、核となる金属であるＡｇよりは標準電極電位が貴なＰｄの被膜を形成し、その後、標準電極電位がＡｇよりも貴でありかつＰｄよりも貴なＡｕを析出させて被膜を形成したので、良好な被覆層が得られず、透明性及び導電性が、塩酸（ＨＣｌ）の環境下、過酸化水素水（Ｈ_２Ｏ_２）の環境下で大幅に悪化した。
【００９７】
［実施例２］
実施例１で得られたＰｄ被覆Ａｕ被覆Ａｇコロイド分散液（Ｄ）を濾過・洗浄し、その後、１００℃にて乾燥し、Ｐｄ被覆Ａｕ被覆Ａｇ微粒子を得た。このＰｄ被覆Ａｕ被覆Ａｇ微粒子２００ｇに、セバシン酸４ｇ、トリエタノールアミン２ｇ、ブチルセルソルブ８０ｇ、レゾール樹脂２０ｇを加え、遊星ミルで予備混合した後、３本ロールにて混練し、導電性接着材料を作製した。
【００９８】
次いで、この導電性接着材料を用いて、ＢＴレジン基板上にスクリーン印刷機にて２００μｍ幅のライン、４０μｍのスペースのテストパターンを印刷し、その後、１６０℃で乾燥、硬化させ、導線パターンを形成した。
この導線パターンが形成された基板に対して通電試験を行った。
この通電試験は、温度９０℃−相対湿度９０％の高温高湿下にて、基板上の導線パターンに１０Ｖの直流電圧を１０００時間通電し、通電試験前、通電５００時間後、通電１０００時間後、それぞれの導線パターンの比抵抗（Ω・ｃｍ）を測定した。
この試験結果を表２に示す。
【００９９】
【表２】

【０１００】
表２によれば、導線パターンの比抵抗は、試験前では１×１０^−５Ω・ｃｍであり、５００時間通電後は３×１０^−５Ω・ｃｍ、１０００時間通電後も３×１０^−５Ω・ｃｍであり、通電試験の前後における比抵抗の変化は僅かなものであった。
【０１０１】
［比較例５］
金属被覆金属微粒子として、比較例１のＡｕ被覆Ａｇコロイド分散液（Ｅ）を濾過・洗浄し、その後、１００℃にて乾燥して得られたＡｕ被覆Ａｇ微粒子を用いた以外は、実施例２と同様の方法により導電性接着材料を作製し、実施例２と同様の評価を行った。
この試験結果を表３に示す。
【０１０２】
【表３】

【０１０３】
表３によれば、導線パターンの比抵抗は、試験前では１×１０^−５Ω・ｃｍであったが、５００時間通電後は５×１０^−１Ω・ｃｍと高くなっており、１０００時間通電後ではショートによる導通不良が発生した。
【０１０４】
【発明の効果】
以上説明したように、本発明の金属被覆金属微粒子によれば、金属微粒子の表面に、該金属微粒子より標準電極電位が貴な金属（Ａ）と、前記金属微粒子よりも標準電極電位が貴でありかつ前記金属（Ａ）よりも標準電極電位が卑な金属（Ｂ）とからなる被覆層を形成したので、透明性、導電性、帯電防止性、電磁波遮蔽性に優れている上に、耐塩水性、耐酸性、耐酸化性、耐紫外線性等の耐環境性を著しく向上させることができる。
【０１０５】
本発明の金属被覆金属微粒子の製造方法によれば、金属微粒子の表面に、該金属微粒子より標準電極電位が貴な金属（Ａ）を析出させ、次いで、前記金属微粒子よりも標準電極電位が貴でありかつ前記金属（Ａ）よりも標準電極電位が卑な金属（Ｂ）を析出させるので、透明性、導電性、帯電防止性、電磁波遮蔽性に優れている上に、耐塩水性、耐酸性、耐酸化性、耐紫外線性等の耐環境性が著しく向上した金属被覆金属微粒子を容易に作製することができる。
【０１０６】
本発明の透明導電膜形成用塗料によれば、本発明の金属被覆金属微粒子を含有したので、透明性、導電性、帯電防止性、電磁波遮蔽性に優れている上に、耐塩水性、耐酸性、耐酸化性、耐紫外線性等の耐環境性を著しく向上させることができる。
【０１０７】
本発明の導電性接着材料によれば、本発明の金属被覆金属微粒子を含有したので、導電性に優れている上に、耐塩水性、耐酸性、耐酸化性、耐紫外線性等の耐環境性を著しく向上させることができる。
【０１０８】
本発明の透明導電膜によれば、本発明の透明導電膜形成用塗料を塗布してなる透明導電層を備えたので、透明性、導電性、帯電防止性、電磁波遮蔽性に優れている上に、耐塩水性、耐酸性、耐酸化性、耐紫外線性等の耐環境性を著しく向上させることができる。
【０１０９】
本発明の表示装置によれば、本発明の透明導電膜を表示面に形成したので、表示面が透明性、導電性、帯電防止性、電磁波遮蔽性に優れている上に、その表示面の耐塩水性、耐酸性、耐酸化性、耐紫外線性等の耐環境性を著しく向上させることができる。
【図面の簡単な説明】
【図１】本発明の一実施形態の金属被覆金属微粒子を示す断面図である。
【符号の説明】
１ 金属微粒子
２ （第１の）被覆層
３ （第２の）被覆層[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a metal coated metal fine particle having excellent environmental resistance such as acid resistance and salt water resistance and excellent conductivity, a method for producing the same, a transparent conductive film forming paint and a conductive adhesive material containing the same, and More specifically, the transparent conductive film and the display device used are, for example, a display surface of various display devices such as a plasma display panel (PDP), a liquid crystal display (LCD), and a cathode ray tube (CRT); a window glass of a building; To form a transparent conductive film which is suitably used for various window materials such as windshields, has an excellent antistatic effect and an electromagnetic wave shielding effect, and has excellent environmental resistance such as acid resistance and salt water resistance. Metal-coated metal particles suitable for use as a coating for forming a transparent conductive film and a method for producing the same, which are excellent in environmental resistance such as acid resistance and salt water resistance by containing the metal-coated metal fine particles The present invention relates to a transparent conductive film forming paint having excellent conductivity, a conductive adhesive material containing the metal-coated metal fine particles, a transparent conductive film using the transparent conductive film forming paint, and a display device having the transparent conductive film. Things.
[0002]
[Prior art]
Conventionally, for example, in various flat displays such as a plasma display panel (PDP), a liquid crystal display (LCD), and an electroluminescence (EL) display, or a cathode ray tube (CRT), an antistatic function and an electromagnetic wave shielding function are provided on the display surface. In order to provide such properties, a transparent conductive film forming paint having excellent antistatic performance and electromagnetic wave shielding performance is applied to a display surface to form a transparent conductive film.
On the other hand, in the case of various window materials such as window glasses of buildings, windshields of automobiles, etc., in order to provide an infrared shielding function, an electromagnetic shielding function, etc., a transparent conductive film having excellent infrared shielding performance and electromagnetic shielding performance is formed. 2. Description of the Related Art A transparent conductive film is formed by applying a paint for display on a display surface.
Also, with the rapid progress of electronics, various conductive adhesive materials have been proposed and used for various electronic devices, electronic components, electronic circuits, optical circuits, and the like.
[0003]
As a commonly used coating material for forming a transparent conductive film, a coating material in which metal fine particles such as silver (Ag), gold (Au), ruthenium (Ru), and palladium (Pd) are dispersed in a base containing a solvent and a binder is used. Is used.
In this coating for forming a transparent conductive film, various properties such as antistatic performance, electromagnetic wave shielding performance, infrared shielding performance, etc. are controlled by controlling the composition, particle size, dispersibility, etc. of the contained metal fine particles to obtain desired characteristics. Is to be expressed.
Examples of the conductive particles used in the paint for forming a transparent conductive film include at least two kinds of noble metal fine particles such as Ag fine particles and Pd fine particles, or those containing noble metal alloy fine particles such as an Ag-Pd type (for example, see Patent Literature). 1) and a metal fine particle formed with a coating made of a metal sulfide (for example, see Patent Document 2).
[0004]
[Patent Document 1]
Patent application re-publication WO97 / 48107
[Patent Document 2]
JP-A-10-204336 (page 3-5, FIG. 1)
[0005]
[Problems to be solved by the invention]
However, the conductive particles used in the above-described conventional transparent conductive film forming paint, for example, when Ag fine particles are used as metal fine particles, although the manufacturing cost can be reduced, the Ag fine particles themselves are corroded by acid or salt water. There was a problem that it was easy. For this reason, paints made using Ag fine particles also have a problem in that they have poor environmental resistance such as acid resistance and salt water resistance, and therefore cannot be used for those requiring environmental resistance. .
Further, when fine particles of Au, Ru, Pd, etc. are used as metal fine particles, since these fine particles have excellent resistance to acid and salt water, paints made using these are also resistant to acid resistance. However, these metal fine particles are more expensive than Ag, Cu, Ni, etc., and thus have a problem that the production cost is higher. Was.
[0006]
Therefore, in order to improve the environmental resistance such as acid resistance and salt water resistance of Ag fine particles, paint for forming an Ag-Pd-based transparent conductive film using a mixed powder of Ag fine particles and Pd fine particles, or Ag-Pd alloy fine particles There have been proposed paints for forming an Ag-Pd alloy-based transparent conductive film using the same, but these paints were insufficient for improving environmental resistance such as acid resistance and salt water resistance.
[0007]
On the other hand, in the case of conductive adhesive materials, metal powders such as Ag, Cu, and Ni are usually used. However, since these metal powders are inferior in oxidation resistance and chemical resistance, a small amount of this conductive adhesive material is used. When used in an atmosphere containing a corrosive gas such as an acidic gas or an alkaline gas, the electric characteristics are lowered and the reliability is deteriorated. Therefore, it has been desired to develop a conductive powder which is excellent in chemical durability such as oxidation resistance and chemical resistance and is inexpensive.
In order to solve such a problem, Cu-Ag alloy powder has been proposed as a conductive powder having improved oxidation resistance. However, even with this Cu-Ag alloy powder, the improvement of environmental resistance is not sufficient. It was not something. Therefore, when the conductive adhesive material is required to have chemical durability, a noble metal powder such as Au, Pd, and Pt or an alloy powder thereof is used as the conductive particles.
[0008]
In order to improve the environmental resistance of the metal fine particles, it is conceivable to coat the surface of the metal fine particles with a metal having excellent environmental resistance, but in this case, the coating layer becomes non-uniform, and the metal fine particles serving as nuclei are removed. In order to completely cover, there were problems such as the coating layer becoming unnecessarily thick. For example, when using Ag colloid and Pd colloid to form Pd-coated Ag fine particles whose surface is completely coated with Pd, the amount of Pd forming the coating layer is 60 wt% based on the weight of Ag. This is necessary, and a large amount of expensive material Pd is required. Further, when it is attempted to form Au-coated Ag fine particles in which the surface of the Ag fine particles is completely coated with Au using the Ag colloid and the Au colloid, the amount of Au forming the coating layer is still 60 wt% with respect to the weight of Ag. % Or more, and a large amount of expensive material Pd was required.
[0009]
The present invention has been made to solve the above problems, and has excellent transparency, conductivity, antistatic property, electromagnetic wave shielding property, salt water resistance, acid resistance, oxidation resistance, ultraviolet light resistance, and the like. Metal-coated metal fine particles having a significantly improved environmental resistance and a method for producing the same, and containing these metal-coated metal fine particles, are excellent in transparency, conductivity, antistatic properties, electromagnetic wave shielding properties, and salt resistance. Environmental resistance such as water resistance, acid resistance, oxidation resistance, ultraviolet resistance, etc. is remarkably improved, and it is possible to form a transparent conductive film which is excellent in adhesion to the substrate and economical. A coating for forming a transparent conductive film, having excellent conductivity by containing this conductive metal-coated metal fine particle, and having significantly improved environmental resistance such as salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance. Conductive adhesive material, The transparent conductive film obtained by applying a transparent conductive film forming coating, and it is an object of this transparent conductive film to provide a display device, which is formed on the display surface.
[0010]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides the following metal-coated metal fine particles, a method for producing the same, a transparent conductive film forming paint and a conductive adhesive material containing the same, a transparent conductive film using the same, and a display. Equipment was adopted.
That is, the metal-coated metal fine particles of the present invention include, on the surface of the metal fine particles, a metal (A) having a higher standard electrode potential than the metal fine particles, and a metal (A) having a higher standard electrode potential than the metal fine particles and ), A coating layer comprising a metal (B) having a lower standard electrode potential than that of the metal (B) is formed.
[0011]
The coating layer is formed on a part of the surface of the metal fine particles and has a first coating layer made of a metal (A) having a standard electrode potential that is more noble than the metal fine particles, and the first coating on the surface of the metal fine particles. And a second coating layer formed of a metal (B) which is formed in a portion other than the layer and has a higher standard electrode potential than the metal fine particles and a lower standard electrode potential than the metal (A). Is preferred.
[0012]
The metal (A) and / or the metal (B) are preferably made of two or more metals.
The metal fine particles preferably have an average particle size of 2 to 200 nm.
[0013]
In the method for producing metal-coated metal fine particles of the present invention, a metal (A) having a standard electrode potential higher than the metal fine particles is precipitated on the surface of the metal fine particles, and then the standard electrode potential is higher than the metal fine particles. In addition, a metal (B) having a lower standard electrode potential than the metal (A) is deposited.
[0014]
The metal (A) and / or the metal (B) are preferably made of two or more metals.
The metal fine particles preferably have an average particle size of 2 to 200 nm.
[0015]
The paint for forming a transparent conductive film of the present invention is characterized by containing the metal-coated metal fine particles of the present invention.
[0016]
The conductive adhesive material of the present invention is characterized by containing the metal-coated metal fine particles of the present invention.
[0017]
The transparent conductive film of the present invention includes a transparent conductive layer formed by applying the transparent conductive film forming paint of the present invention.
It is preferable that an anti-reflection layer is formed on one main surface or both main surfaces of the transparent conductive layer.
[0018]
The display device of the present invention is characterized in that the transparent conductive film of the present invention is formed on a display surface.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the metal-coated metal fine particles of the present invention, a method for producing the same, a paint for forming a transparent conductive film and a conductive adhesive material containing the same, a transparent conductive film using the same, and a display device will be described.
This embodiment is specifically described for better understanding of the gist of the invention, and does not limit the invention unless otherwise specified.
[0020]
`` Metal coated metal fine particles ''
The metal-coated metal fine particles of the present embodiment include, on the surface of the metal fine particles, a metal (A) having a standard electrode potential nobleer than the metal fine particles, and a metal (A) having a standard electrode potential nobleer than the metal fine particles. A coating layer made of a metal (B) having a lower standard electrode potential than that of the metal (B) is formed.
[0021]
The coating layer is formed on a part of the surface of the metal fine particles and has a first coating layer made of a metal (A) having a standard electrode potential that is more noble than the metal fine particles, and the first coating on the surface of the metal fine particles. And a second coating layer formed of a metal (B) which is formed in a portion other than the layer and has a higher standard electrode potential than the metal fine particles and a lower standard electrode potential than the metal (A). Is preferred.
[0022]
FIG. 1 is a cross-sectional view showing the metal-coated metal fine particles of the present embodiment. In the drawing, reference numeral 1 denotes metal fine particles serving as a central nucleus, and 2 denotes a metal fine particle 1 covering a part of the surface of the metal fine particles 1. The (first) coating layer 3 made of the metal (A) having a noble standard electrode potential is formed on the surface of the metal fine particles 1 except for the coating layer 2, and has a noble standard electrode potential than the metal fine particles 1 and The (second) coating layer is made of a metal (B) having a lower standard electrode potential than the metal (A).
[0023]
The material of the metal fine particles 1 is not particularly limited, but is excellent in conductivity, low in production cost, has a high metal ionic strength as compared with other metals, and is compared with the metal-coated metal fine particles of the present embodiment. (Ag), copper (Cu), and nickel (Ni) are the only metals that are easy to manufacture and are inexpensive materials because they are relatively abundant on the earth as resources. It is preferable that one or two or more kinds selected from Ag, Cu, and Ni are contained like the fine particles or alloy fine particles thereof.
[0024]
The particle size of the metal fine particles 1 is not particularly limited, but when used in a transparent conductive film forming paint from the viewpoint of transparency and conductivity, a particle size of 2 to 200 nm is preferable, A preferred particle size is 2 to 100 nm, and a more preferred particle size is 5 to 30 nm.
The reason for this is that if the particle size is smaller than 2 nm, the dispersibility becomes worse, the transparency of the formed film decreases, and the conductivity also worsens. This is because the transparency of the resulting film deteriorates.
Further, when used for a conductive adhesive material, a particle size of 5 nm to 10 μm is preferable, and when transparency is particularly required, a particle size of 5 to 20 nm is preferable.
[0025]
The metal fine particles 1 may be produced by any method. For example, a metal salt is reduced in a solution using a reducing agent such as sodium borohydride, formalin, hydrazine or alcohol. Colloidal metal fine particles obtained by a so-called liquid phase reduction method are preferably used when used in a paint for forming a transparent conductive film.
[0026]
The material of the metal (A) constituting the coating layer 2 is not particularly limited as long as it is a metal having a higher standard electrode potential than the metal fine particles 1, but Au and Ir having excellent chemical stability are used. , Pt, Rh, Ru, Pd, or one or more selected from the group.
These metals are excellent in chemical resistance such as salt water resistance, acid resistance, oxidation resistance, etc., corrosion resistance, and also excellent in heat resistance. Effects can be exhibited.
[0027]
The material of the metal (B) constituting the coating layer 3 is particularly limited as long as the metal has a noble standard electrode potential than the metal fine particles 1 and a low standard electrode potential than the metal (A). However, one or more selected from the group of Ir, Pt, Rh, Ru, Pd, and Ag, which are metals having excellent chemical stability and excellent conductivity, are preferable.
[0028]
As a preferable combination of these metals (A) and (B), for example, when the metal fine particles 1 are silver (Ag) fine particles, the metal (A) is gold (Au) and the metal (B) is platinum (Pt). ), Palladium (Pd), iridium (Ir), ruthenium (Ru), rhodium (Rh) and the like are preferably used, and Pd is particularly preferable.
When the metal fine particles 1 are copper (Cu) fine particles, Au is preferable as the metal (A) and Ag is preferable as the metal (B).
[0029]
The amount of the metal (A) constituting the coating layer 2 (when two or more kinds are used, the total amount thereof) is preferably 1 to 50% by weight with respect to the metal fine particles 1, and the amount of the metal (A) constituting the coating layer 3 ( The amount of B) (when two or more kinds are used, the total amount) is preferably 1 to 50% by weight based on the metal fine particles 1.
Further, the total amount of the metal (A) and the metal (B) is preferably 3 to 50% by weight based on 1 of the metal fine particles. The reason is that if it is less than 3% by weight, it is difficult to obtain oxidation resistance and chemical resistance, and if it exceeds 50% by weight, even if it is further added, furthermore, such as conductivity, oxidation resistance, chemical resistance, etc. This is because no improvement effect can be expected.
[0030]
The thickness of the coating layers 2 and 3 is not particularly limited, but is preferably 0.2 to 100 nm. The reason is that if the thickness is less than 0.2 nm, contact between the metal fine particles 1 serving as a central nucleus and a gas such as an oxidizing gas, a corrosive gas, water vapor, or salt water, which deteriorates the conductivity of the metal fine particles 1. If the thickness is more than 100 nm, the metal fine particles 1 serving as the central nucleus have resistance to salt water, acid, oxidation, and ultraviolet. This is because the environmental property does not further increase, and if the coating layer is increased more than necessary, the cost of raw materials increases when a noble metal such as Au, Pt, or Pd is used.
[0031]
The preferable thickness of these coating layers 2 and 3 is preferably 0.2 to 50 nm, particularly in the case where the coating layers 2 and 3 are used for a paint for forming a transparent conductive film, in view of the relationship with the particle diameter of the metal fine particles 1 serving as the central nucleus. Preferably it is 1 to 50 nm, more preferably 2 to 20 nm.
[0032]
In the metal-coated metal fine particles of the present embodiment, the coating layer formed on the surface of the metal fine particles 1 has a coating layer 2 made of a metal (A) having a nobleer standard electrode potential than the metal fine particles 1, Since the coating layer 3 is made of the metal (B) having a noble standard electrode potential and a lower standard electrode potential than the metal (A), the thickness of these coating layers 2 and 3 is small. In addition, environmental resistance such as salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance can be improved.
Although the coating layer 3 is formed on the surface of the metal fine particles 1 except for the coating layer 2, the coating layer 3 may be formed so as to cover part or all of the coating layer 2.
[0033]
Next, a method for producing the metal-coated metal fine particles of the present embodiment will be described.
In this manufacturing method, first, a coating layer 2 is formed by depositing a metal (A) having a noble standard electrode potential from the metal fine particles 1 on the surface of the metal fine particles 1 serving as a nucleus.
[0034]
The coating layer 2 can be formed by depositing the metal (A) by ion exchange utilizing the difference in standard electrode potential, adsorption of particles, precipitation on the metal surface, or a method combining these.
Here, the particle size of the metal fine particles 1 is not particularly limited, but is preferably 2 to 200 nm, and 2 to 100 nm when used for a transparent conductive film forming paint from the viewpoint of transparency and conductivity. Is more preferable, 2 to 30 nm is further preferable, and 5 to 30 nm is most preferable.
[0035]
The reason for this is that if the particle size is less than 2 nm, the dispersibility becomes worse, the transparency of the formed film decreases, and the conductivity also decreases. This is because the transparency of the formed film is reduced.
Further, when used for a conductive adhesive material, a particle size of 5 nm to 10 μm is preferable, and when transparency is particularly required, a particle size of 5 to 20 nm is preferable.
[0036]
Next, a metal (B) having a higher standard electrode potential than the metal fine particles 1 and a lower standard electrode potential than the metal (A) is deposited on the metal fine particles 1 on which the coating layer 2 is formed. The coating layer 3 is formed.
The metal (B) precipitates on the surface of the metal fine particles 1 where the coating layer 2 is not formed or on the portion where the coating layer 2 is not perfect, so that only the metal (A) completely removes the metal fine particles 1. Even when the amount of metal forming the coating layer is smaller than when the surface is coated, the metal fine particles 1 can be completely coated.
Further, since the surface of the metal fine particles 1 is covered with the two types of coating layers 2 and 3, the thickness of the coating layer can be reduced.
[0037]
When two or more types of metal (B) are used, these metals are referred to as metal (B1), metal (B2), metal (B3),..., And the standard electrode potentials of these metals are ranked in ascending order. In this case, it is preferable that each standard electrode potential satisfies the following relational expression.
Metal (A)> Metal (B1)> Metal (B2)> Metal (B3)>...> Microparticles 1 These metals are preferably deposited in the order of noble standard electrode potential. In the above case, it is preferable to deposit metal (B1), metal (B2), metal (B3),... In this order.
[0038]
Like the coating layer 2, the coating layer 3 is formed by depositing the metal (B) by ion exchange utilizing the difference in standard electrode potential, adsorption of particles, deposition on the metal surface, or a combination thereof. can do.
[0039]
In this manufacturing method, the amount of the metal (A) constituting the coating layer 2 (when two or more kinds are used, the total amount thereof) can be 1 to 50% by weight based on the metal fine particles 1. The amount of the metal (B) constituting 3 (when two or more kinds are used, the total amount thereof) can be 1 to 50% by weight based on the metal fine particles 1.
Further, the total amount of the metal (A) and the metal (B) can be 3 to 50% by weight based on the metal fine particles 1. Therefore, the amount of metal used for the coating layers 2 and 3 can be reduced.
Further, since the coating layers 2 and 3 can be made thin, the particle diameter of the original metal fine particles 1 serving as a nucleus does not change much, and the metal-coated metal which does not hinder the characteristics of the metal fine particles 1 serving as a nucleus Fine particles can be produced.
[0040]
For example, if only one type of metal is deposited on the surface of the metal fine particles 1 having the above-mentioned particle size by a conventional method and segregation is performed, segregation will inevitably occur. Requires much more metal than originally required. More specifically, if an attempt is made to form a Pd coating layer using an Ag colloid and a Pd salt so as to completely cover the surface of the Ag fine particles, the amount of Pd required for the Pd coating layer is based on the weight of Ag. 60% by weight or more, and a large amount of expensive Pd is required. Further, when an Au coating layer is formed so as to completely cover the surface of Ag fine particles using an Ag colloid and an Au colloid, the amount of Au required for the Au coating layer is still 60 wt% or more based on the weight of Ag. It is necessary, and much Au, which is an expensive material, is required.
Thus, in the manufacturing method of the present embodiment, the amount of metal used for the coating layers 2 and 3 can be reduced without hindering the characteristics of the metal fine particles 1.
[0041]
"Colloidal dispersion"
By subjecting the above-mentioned metal-coated metal fine particles to a usual washing method such as electrodialysis, a colloidal dispersion can be obtained. In particular, the colloidal dispersion using the metal-coated metal fine particles of the present embodiment includes a coating layer 2 made of a metal (A) having a noble standard electrode potential on the surface of the metal fine particles 1 serving as a central nucleus. And a coating layer 3 made of a metal (B) having a higher standard electrode potential than the metal fine particles 1 and a lower standard electrode potential than the metal (A). Thus, a dispersion having extremely high stability and a high concentration of metal-coated metal fine particles can be obtained.
[0042]
`` Paint for forming transparent conductive film ''
By adding the above-mentioned colloidal dispersion to a solvent, the paint for forming a transparent conductive film of the present embodiment can be obtained.
Examples of the solvent include water and an organic solvent. Examples of the organic solvent include alcohols such as methanol, ethanol, propanol, and butanol, β-oxyethyl methyl ether (ethylene glycol monomethyl ether (methyl cellosolve)), β- Ethers such as oxyethyl ether (ethylene glycol monoethyl ether (ethyl cellosolve)) and butyl-β-oxyethyl ether (ethylene glycol monobutyl ether (butyl cellosolve)), phenols, esters, ketones, glycols, and aromatics And the like.
[0043]
This transparent conductive film forming paint is, in addition to the metal-coated metal fine particles described above, a dye, an organic pigment, or a chemically stable noble metal as a coloring agent for adjusting the color tone of light transmitted through the transparent conductive film. A minute amount of fine particles may be contained.
The coloring material may be added to any of the layers constituting the transparent conductive film. For example, when the coloring material is added to the transparent conductive layer, the addition amount is 20% by weight or less based on the content of the metal particles, particularly It is preferable that the content be 10% by weight or less.
The reason for this is that if the addition amount exceeds 20% by weight, the conductivity and the strength of the film deteriorate, and the electromagnetic wave shielding effect is hindered.
[0044]
Examples of the coloring material include, for example, monoazo pigment, quinacridone, iron oxide yellow, disazo pigment, phthalocyanine green, phthalocyanine blue, cyanine blue, flavanthrone yellow, dianthraquinolyl red, indanthrone blue, thioindigo bordeaux, Organic pigments such as perylene orange, perylene scarlet, perylene red 178, perylylene maroon, dioxazine violet, isoindoline yellow, nickel nitroso yellow, madder lake, copper azomethine yellow, aniline black, and alkali blue are preferably used.
[0045]
In addition, zinc white, titanium oxide, red iron oxide, chrome oxide, iron black, titanium erotic, cobalt blue, cerulean blue, cobalt green, alumina white, viridian, cadmium yellow, cadmium red, vermilion, lithopone, graphite, molybdate orange Also, inorganic pigments such as zinc chromate, calcium sulfate, barium sulfate, calcium carbonate, lead white, ultramarine, manganese violet, emerald green, navy blue, and carbon black are preferably used.
[0046]
Further, various dyes such as azo dyes, anthraquinone dyes, indigoid dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes, naphthoquinone dyes, naphthalimide dyes, and perinone dyes are also suitable. Used for
These coloring materials can be used alone or in combination of two or more.
[0047]
Further, in addition to the various components described above, the transparent conductive film forming paint may further include other components such as silicon (Si), aluminum (Al), and zirconium (if necessary) for the purpose of improving film strength and conductivity. Oxidation of Zr), cerium (Ce), titanium (Ti), yttrium (Y), zinc (Zn), magnesium (Mg), indium (In), tin (Sn), antimony (Sb), gallium (Ga), etc. Or a composite oxide, a nitride, or the like. In particular, an oxide of indium (In) or tin (Sn), a composite oxide, or inorganic fine particles mainly containing a nitride, etc. May be contained.
[0048]
Further, organic synthetic resins such as polyester resin, acrylic resin, epoxy resin, melamine resin, urethane resin and butyral resin, hydrolysates of metal alkoxides such as silicon, titanium and zirconium, or organic compounds such as silicone monomers and silicone oligomers. An inorganic binder component or the like may be contained.
As the organic synthetic resin, visible light curable resin, ultraviolet curable resin, electron beam curable resin, thermosetting resin, thermoplastic resin, etc. are used. Considering this, a visible light curable resin or an ultraviolet curable resin is preferable.
[0049]
"Transparent conductive film"
The transparent conductive film provided with the transparent conductive layer of the present embodiment is obtained by applying the above-mentioned transparent conductive film forming paint to a surface of a substrate such as a glass substrate, a heat-resistant transparent resin, and a glass plate. Can be.
Known application techniques such as spin coating, spray coating, dip coating, roll coating, bar coating, and gravure printing can be used as the coating method.
Among these, spin coating, spray coating, and dip coating are each a particularly preferable coating method because a film having a uniform thickness can be formed in a short time.
[0050]
After the application, the applied film is dried and baked if necessary, whereby a transparent conductive layer can be formed on the surface of the substrate.
At the time of coating, it is preferable to set the coating amount so that the thickness of the formed transparent conductive layer is 5 nm to 100 nm. Further, it is preferable that the thickness of the formed transparent conductive layer be 10 nm to 50 nm.
[0051]
The reason for this is that if the film thickness is less than 5 nm, not only is it difficult to obtain a sufficient electromagnetic wave shielding effect, but also it becomes difficult to form a uniform film due to unevenness in appearance and the like, while the film thickness exceeds 100 nm. This is because, although there is no problem in conductivity, the light transmittance of the transparent conductive layer is remarkably reduced, so that practical transparency cannot be obtained. Here, the practical transparency means that the total light transmittance is about 40% or more.
[0052]
The transparent conductive film of the present embodiment can be used on a display surface of a display panel of various display devices such as a plasma display panel (PDP), a liquid crystal display (LCD), an electroluminescence (EL) display, a touch panel, and a cathode ray tube (CRT). Can be applied.
In addition, the present invention can be applied to various window materials such as window glasses of buildings and the like, windshields of automobiles, instrument panels of automobiles, and viewing windows of microwave ovens.
[0053]
According to the above-mentioned display device and various window materials, halogen salts such as salt water produced by seawater during transportation by sea or sweat of operators, hydrogen sulfide gas in hot springs, etc., and SO in the atmosphere _x High resistance to gas, acid liquid such as acid rain, oxidizing gas such as ozone generated by acid gas, ultraviolet ray, etc., and electromagnetic wave shielding for a long period of time even if placed in an environment containing these deterioration factors Properties, anti-reflection properties, hue, film strength, etc. can be maintained.
[0054]
In the transparent conductive film of the present embodiment, environmental resistance such as salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance is remarkably improved.
Further, in the above display device, since the transparent conductive film of the present embodiment is formed on the display surface, environmental resistance such as salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance on the display surface is significantly improved. .
In addition, since the adhesion between the display surface and the transparent conductive film is improved, there is no possibility that defects such as peeling and scratches may occur even during use, and visibility and reliability on the display surface are improved.
[0055]
"Transparent conductive film with anti-reflection layer"
The transparent conductive film having the antireflection layer of the present embodiment will be described.
The transparent conductive film having the anti-reflection layer has a refractive index of the transparent conductive layer on the upper or lower layer (either main surface), or on the upper and lower layers (both main surfaces). Is formed with one or more transparent antireflection layers having different refractive indices. This antireflection layer is used for removing or reducing external light reflection at the interface of the film by an interference effect.
[0056]
This anti-reflection layer is not only practically sufficient to prevent the reflection of external light and to improve the visibility of the display device but also to protect the low-reflection transparent conductive film from external force. It is necessary to have mechanical strength.
[0057]
Examples of the coating agent for forming the anti-reflection layer include thermoplastic resins such as polyester resin, acrylic resin, epoxy resin, and butyral resin, thermosetting resins, and photo / electron beam curable resins, silicon, aluminum, and zirconium. And a coating solution containing one or more components selected from a hydrolyzate of a metal alkoxide such as titanium, a silicone monomer or a silicone oligomer. The above components can be used alone or as a mixture.
[0058]
The formation of the anti-reflection layer is performed in the same manner as the formation of the transparent conductive layer by a method of uniformly applying a coating solution containing one or more of the above-described components, that is, an anti-reflection coating to a predetermined surface to form a film. It can be carried out. As a coating method, a spin coating method, a roll coating method, a spray coating method, a dip coating method, a bar coating method, a gravure printing method, or the like is suitably used.
After the application, the applied film is dried, and preferably a strong film is formed by baking or irradiating light and electron beams.
[0059]
The transparent conductive film having the antireflection layer according to the present embodiment is, for example, a plasma display panel (PDP), a liquid crystal display (LCD), an electroluminescence (EL) display, a touch panel, a cathode ray tube (CRT), like the transparent conductive film described above. ) Can be applied to the display surface of the display panel of various display devices.
In addition, the present invention can be applied to various window materials such as window glasses of buildings and the like, windshields of automobiles, instrument panels of automobiles, and viewing windows of microwave ovens.
[0060]
`` Conductive adhesive material ''
Hereinafter, the conductive adhesive material of the present embodiment will be described.
The conductive adhesive material of the present embodiment contains the metal-coated metal fine particles of the present embodiment, and the conductive adhesive material has the following four types.
(1) The conductive adhesive material A comprising the metal-coated metal fine particles of the present embodiment and a solvent
(2) Conductive adhesive material B comprising metal-coated metal fine particles of the present embodiment and a binder
(3) The conductive adhesive material C comprising the metal-coated metal fine particles of the present embodiment, a solvent, and a binder
(4) A conductive adhesive material D in which any of the above (1) to (3) is fixed on a substrate
[0061]
Next, each of the conductive adhesive materials A to D will be described.
"Conductive adhesive material A"
This conductive adhesive material can be prepared by using the metal-coated metal fine particles of the present embodiment with an anionic, cationic, or polymer type surfactant to form water, alcohols, phenols, esters, ketones, or ethers. And a known solvent such as aromatic compounds.
[0062]
Examples of known solvents include alcohols such as methanol, ethanol, propanol, and butanol. Examples of phenols include terpineol. Examples of the esters include ethyl acetate and butyl acetate. Ketones include methyl ethyl ketone and methyl isobutyl ketone.
[0063]
As ethers, β-oxyethyl methyl ether (ethylene glycol monomethyl ether (methyl cellosolve)), β-oxyethyl ether (ethylene glycol monoethyl ether (ethyl cellosolve)), butyl-β-oxyethyl ether (ethylene glycol monosolve) Butyl ether (butyl cellosolve)), ethylene glycol dimethyl ether, ethylene glycol-n-exyl ether and their acetates, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monohexyl ether and their acetates, triethylene glycol monoalkyl And their acetates.
Other solvents include dioxane, dimethylacetamide, dimethylformamide, N-methylpyrrolidone, lactone and the like.
The solvent preferably contains at least one kind or two or more kinds.
[0064]
"Conductive adhesive material B"
The conductive adhesive material is made of the metal-coated metal fine particles of the present embodiment, and an organic binder composed of an organic resin such as a thermoplastic resin, a thermosetting resin, a photocurable resin, an electron beam curable resin, or a pressure-sensitive resin as a binder. And an organic metal binder such as polycondensate of polysilane and metal alkoxide, and an inorganic binder such as glass frit.
[0065]
As organic binders, ethyl cellulose, hydroxyethyl cellulose, methyl cellulose, nitrocellulose, ethyl cellulose derivatives, polyvinyl alcohol, polyethylene oxide, polyalkylene oxide, acrylic resin, butyral resin, phenolic resin, polyurethane resin, polyester resin, alkyd resin, acetic acid It can be selected from vinyl resins, ethylene-vinyl acetate copolymers, styrene resins, epoxy resins, amino resins, polyimide resins, melamine alkyd resins, resole resins, and modified resins thereof.
[0066]
"Conductive adhesive material C"
This conductive adhesive material is a conductive adhesive material obtained by mixing the metal-coated metal fine particles of the present embodiment, the solvent used for the conductive adhesive material A, and the binder used for the conductive adhesive material B.
[0067]
"Conductive adhesive material D"
This conductive adhesive material is a conductive adhesive material obtained by applying the conductive adhesive materials of the above-described conductive adhesive materials A to C onto a base material such as a plastic film, a plastic plate, a metal plate, and a glass plate.
[0068]
Various known additives may be added to these conductive adhesive materials A to D as necessary. For example, a known viscosity adjuster, diluent, sedimentation inhibitor, leveling agent, defoaming agent and the like may be added.
[0069]
The substrate to which the conductive adhesive materials A to D can be applied is not particularly limited, but examples thereof include a glass substrate, a metal substrate such as aluminum and stainless steel, a ceramic substrate such as alumina and aluminum nitride, a silicon wafer, and gallium arsenide. Semiconductor substrate such as wafer, glass epoxy resin substrate, paper phenol resin substrate, polyimide substrate, polyester resin substrate, BT resin substrate, polysulfone resin substrate, polyethersulfone resin substrate, polyetherimide resin substrate, polybutadiene resin substrate, glass polyimide Various substrates such as a flexible substrate such as a resin substrate and a resin substrate can be used.
[0070]
Since the conductive adhesive material of the present embodiment contains the metal-coated metal fine particles of the present embodiment, it is possible to provide a conductive adhesive material that does not cause conductive failure due to oxidation or corrosion of the conductive particles. it can.
In addition, this conductive adhesive material can be used for electrodes, circuit wiring, conductive joints, conductive films, and the like of various electronic devices and the like. Electronic devices and the like manufactured using this conductive adhesive material include halogen salts such as salt, hydrogen sulfide gas in hot springs and the like, and SO 2 in the atmosphere. <sub>x</sub> Troubles such as disconnection and poor conductivity are extremely severe even when used in a severe environment containing deterioration factors such as gas, acid liquid such as acid rain, acid gas, and oxidizing gas such as ozone generated by ultraviolet rays. Will be less.
[0071]
"Display device"
The display device of the present embodiment has a transparent conductive film of the present embodiment or a transparent conductive film having an antireflection layer formed on the display surface thereof. The display device of the present embodiment can be obtained by applying it to a display surface of a transparent substrate such as a display panel (PDP), a liquid crystal display (LCD), an electroluminescence (EL) display, a touch panel, and a cathode ray tube (CRT). .
[0072]
According to the display device of the present embodiment, the electromagnetic wave radiated from the display device can be shielded by the transparent conductive film or the transparent conductive film having the anti-reflection layer, and various types of electromagnetic wave interference can be prevented.
Further, since this transparent conductive film is excellent in light transmittance, an image becomes bright. Further, since the reflection of external light is reduced, the visibility on the display surface is improved.
[0073]
Further, similarly to the case where the transparent conductive film is formed, a halogen salt such as a salt brought from seawater during transportation by sea or an operator's sweat, a hydrogen sulfide gas in a hot spring area or the like, and a SO 3 gas in the atmosphere are also used. <sub>x</sub> High resistance to oxidizing gas such as ozone generated by gas, acid liquid such as acid rain, acid gas, ultraviolet ray, etc., and electromagnetic wave shielding for a long period of time even if placed in an environment containing these deterioration factors Properties, anti-reflection properties, hue, film strength, etc. can be maintained.
[0074]
【Example】
Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
[0075]
Ag colloidal dispersions used in the following Examples and Comparative Examples and coatings for forming transparent films were prepared by the following methods.
"Ag colloid dispersion"
A 0.15 mmol / l aqueous solution of silver nitrate and a 0.024 mmol / l aqueous solution of sodium borohydride are mixed, and the obtained colloidal dispersion is concentrated to form an Ag colloidal dispersion containing 0.65 mol / l Ag fine particles. (A) was obtained. The average primary particle size of the silver fine particles in this dispersion (A) was 10 nm.
[0076]
`` Paint for forming transparent film ''
0.8 g of tetraethoxysilane, 0.8 g of 0.1 N hydrochloric acid, and 98.4 g of ethanol were mixed to obtain a transparent solution-forming coating material (B) of a uniform solution.
[0077]
[Example 1]
After 93 g of the Ag colloidal dispersion liquid (A) was dispersed in 4 liters of pure water, the pH was adjusted to 10 using a 0.1N aqueous NaOH solution to obtain a solution a.
Next, sodium gold sulfite was weighed so that the Au solid content was 5 wt% with respect to the Ag solid content in the above solution a, and pure water was further added to obtain a solution b having a total volume of 1 liter.
Next, while stirring the solution a, the solution b was dropped into the solution a over 1 hour, and 0.05N acetic acid was dropped over 1 hour to adjust the pH to 5.0.
After the resulting solution was stirred for 24 hours, it was filtered and washed to remove excess ions to obtain an Au-coated Ag colloidal dispersion (C).
[0078]
Pure water was added to the Au-coated Ag colloidal dispersion (C) to make the total volume 4 liters, and 0.1 N acetic acid was dropped into this dispersion to adjust the pH to 4, thereby obtaining a solution c.
Next, palladium acetate was weighed so that the Pd solid content was 5 wt% with respect to the Ag solid content in the solution c, and pure water was further added to obtain a solution d having a total volume of 1 liter.
[0079]
Then, while stirring the solution c, the above solution d was added dropwise to the solution c over 1 hour, and further, a 0.05N aqueous sodium hydroxide solution was added dropwise over 1 hour to adjust the pH to 10. .
After stirring the obtained solution for 24 hours, filtration and washing were performed to remove excess ions, and the solution was further concentrated to 200 ml, and a Pd-coated Au-coated Ag colloid dispersion having a total solid content of 3 wt% (D) Got.
[0080]
Then
2 g of Pd-coated Au-coated Ag colloid dispersion (D)
43 g of ethanol
3g of water
Ethyl Solosolve 2g
Was mixed uniformly with an ultrasonic dispersing machine (Sonifire 450: manufactured by BRANSON ULTRASONICS) to obtain a paint for forming a transparent conductive film.
Next, this coating material was applied on a glass substrate by a spin coater, dried at 40 ° C., and then the above-mentioned coating material (B) for forming a transparent film was applied thereon in the same manner.
After heating this glass substrate at 160 ° C. for 30 minutes, it was allowed to cool to room temperature (25 ° C.) to obtain a substrate with a transparent conductive film of Example 1.
[0081]
[Comparative Example 1]
After 93 g of the Ag colloidal dispersion liquid (A) was dispersed in 4 liters of pure water, the pH was adjusted to 10 using a 0.1N aqueous NaOH solution to obtain a solution a.
Next, sodium gold sulfite was weighed so that the Au solid content was 10 wt% with respect to the Ag solid content in the above solution a, and pure water was further added to obtain a solution e having a total volume of 1 liter.
Next, while stirring the solution a, the solution e was dropped into the solution a over 2 hours, and further, 0.05 N acetic acid was dropped to adjust the pH to 5.0.
The resulting solution was stirred for 24 hours, filtered and washed to remove excess ions, and further concentrated to a total volume of 200 ml, and a Au-coated Ag colloid dispersion (E) having a total solid content of 3 wt% Got.
[0082]
Then
Au-coated Ag colloid dispersion (E) 2g
43 g of ethanol
3g of water
Ethyl Solosolve 1.2g
Was mixed uniformly with an ultrasonic dispersing machine (Sonifire 450: manufactured by BRANSON ULTRASONICS) to obtain a paint for forming a transparent conductive film.
Next, this coating material was applied on a glass substrate by a spin coater, dried at 40 ° C., and then the above-mentioned coating material (B) for forming a transparent film was applied thereon in the same manner.
After heating this glass substrate at 160 ° C. for 30 minutes, it was allowed to cool to room temperature (25 ° C.) to obtain a substrate with a transparent conductive film of Comparative Example 1.
[0083]
[Comparative Example 2]
After 93 g of the Ag colloid dispersion liquid (A) was dispersed in 4 liters of pure water, the pH was adjusted to 4 with 0.1 N acetic acid to obtain a solution f.
Next, palladium acetate was weighed so that the Pd solid content was 10 wt% with respect to the Ag solid content in the above solution f, and pure water was further added to obtain a solution g having a total volume of 1 liter.
Next, while stirring the solution f, the above solution g was dropped into the solution f over 2 hours, and further, a 0.05N aqueous NaOH solution was dropped to adjust the pH to 9.0.
After the resulting solution was stirred for 24 hours, it was washed by ultrafiltration to remove excess ions, further concentrated to a total volume of 200 ml, and a Pd-coated Ag colloidal dispersion having a total solid content of 3 wt% ( F) was obtained.
[0084]
Then
2 g of Pd-coated Ag colloid dispersion (F)
43 g of ethanol
3g of water
Ethyl Solosolve 1.2g
Was mixed uniformly with an ultrasonic dispersing machine (Sonifire 450: manufactured by BRANSON ULTRASONICS) to obtain a paint for forming a transparent conductive film.
Next, this coating material was applied on a glass substrate by a spin coater, dried at 40 ° C., and then the above-mentioned coating material (B) for forming a transparent film was applied thereon in the same manner.
After heating this glass substrate at 160 ° C. for 30 minutes, it was allowed to cool to room temperature (25 ° C.) to obtain a substrate with a transparent conductive film of Comparative Example 2.
[0085]
[Comparative Example 3]
After 93 g of the Ag colloid dispersion liquid (A) was dispersed in 4 liters of pure water, the pH was adjusted to 4 with 0.1 N acetic acid to obtain a solution f.
Next, palladium acetate was weighed so that the Pd solid content was 5 wt% with respect to the Ag solid content in the above solution f, and pure water was further added to obtain a solution h having a total volume of 1 liter.
Then, while stirring the solution f, the above solution h was added dropwise to the solution f over 1 hour, and further, a 0.05N aqueous solution of NaOH was added dropwise over 1 hour to adjust the pH to 10.0. .
After the resulting solution was stirred for 24 hours, it was filtered and washed to remove excess ions to obtain a Pd-coated Ag colloidal dispersion (G).
[0086]
Pure water was added to the Pd-coated Ag colloidal dispersion (G) to make the total volume 4 liters, and a 0.1N NaOH aqueous solution was dropped into this dispersion to adjust the pH to 10 to obtain a solution j. .
Next, sodium gold sulfite was weighed so that the Au solid content was 5 wt% with respect to the Ag solid content in the above solution j, and pure water was further added to obtain a solution k having a total volume of 1 liter.
[0087]
Next, while stirring the solution j, the solution k was dropped into the solution j over 1 hour, and 0.05N acetic acid was dropped over 1 hour to adjust the pH to 5.
After stirring the obtained solution for 24 hours, filtration and washing were performed to remove excess ions, and the solution was further concentrated to 200 ml to obtain a Au-coated Pd-coated Au-coated Ag colloidal dispersion having a total solid content of 3 wt%. (H) was obtained.
[0088]
Then
2 g of Pd-coated Au-coated Ag colloid dispersion (H)
43 g of ethanol
3g of water
Ethyl Solosolve 2g
Was mixed uniformly with an ultrasonic dispersing machine (Sonifire 450: manufactured by BRANSON ULTRASONICS) to obtain a paint for forming a transparent conductive film.
Next, this coating material was applied on a glass substrate by a spin coater, dried at 40 ° C., and then the above-mentioned coating material (B) for forming a transparent film was applied thereon in the same manner.
After heat-treating this glass substrate at 160 ° C. for 30 minutes, it was allowed to cool to room temperature (25 ° C.) to obtain a substrate with a transparent conductive film of Comparative Example 3.
[0089]
[Comparative Example 4]
While stirring the solution a of Example 1, the solution b of Example 1 was added dropwise to the solution a over 2 hours, and further, 0.05 N acetic acid was added dropwise to adjust the pH to 5.0.
After stirring the obtained solution for 24 hours, filtration and washing were performed to remove excess ions, and the solution was further concentrated to 200 ml to obtain an Au-coated Ag colloidal dispersion (J) having a total solid content of 3 wt%. Obtained.
[0090]
Then
Au-coated Ag colloid dispersion (J) 2g
43 g of ethanol
3g of water
Ethyl Solosolve 2g
Was mixed uniformly with an ultrasonic dispersing machine (Sonifire 450: manufactured by BRANSON ULTRASONICS) to obtain a paint for forming a transparent conductive film.
Next, this coating material was applied on a glass substrate by a spin coater, dried at 40 ° C., and then the above-mentioned coating material (B) for forming a transparent film was applied thereon in the same manner.
After heating this glass substrate at 160 ° C. for 30 minutes, it was allowed to cool to room temperature (25 ° C.) to obtain a substrate with a transparent conductive film of Comparative Example 4.
[0091]
[Evaluation]
The surface resistance, transmittance, HCl (hydrochloric acid) resistance, and H resistance of the transparent conductive films of Example 1 and Comparative Examples 1 to 4 obtained as described above. ₂ O ₂ Each item of (hydrogen peroxide) property was evaluated using the following method and apparatus.
[0092]
Surface resistance value: Using a resistance measuring device (Loresta AP: manufactured by Mitsubishi Yuka Co., Ltd.)
The surface resistance was measured by a four-terminal method.
Transmittance: Measured using an Automatic Haze Meter HIDP manufactured by Tokyo Denshoku Co., Ltd.
HCl resistance: After immersion in 10% HCl for 7 days, the appearance of the transparent conductive film was visually evaluated. Further, the surface resistance of the transparent conductive film before and after immersion in hydrochloric acid was measured, and the rate of change (surface resistance change) was determined.
[0093]
H resistance ₂ O ₂ Properties: 10% aqueous hydrogen peroxide (H ₂ O ₂ ) For 7 days, and the appearance of the transparent conductive film was visually evaluated. The surface resistance of the transparent conductive film before and after immersion in the hydrogen peroxide solution was measured, and the rate of change (surface resistance change) was determined.
Table 1 shows the evaluation results of Example 1 and Comparative Examples 1 to 4.
[0094]
[Table 1]

[0095]
According to the results shown in Table 1, in Example 1, a coating of Au having a higher standard electrode potential than that of Ag was formed on the surface of Ag fine particles serving as nuclei, and thereafter, the standard electrode potential was higher than that of Ag. A Pd film, which is more base than Au, is formed, and has good transparency and conductivity. Further, the transparency and conductivity are determined in an environment of hydrochloric acid (HCl) in a hydrogen peroxide solution (H ₂ O ₂ ), It hardly changes even in the environment of not only excellent transparency, conductivity, antistatic property, etc. but also HCl resistance and H resistance. ₂ O ₂ It was confirmed that it was excellent in environmental resistance such as properties.
[0096]
On the other hand, in Comparative Examples 1, 2, and 4, since only one type of metal was deposited on the surface of the Ag fine particles to form a film, the initial transparency and conductivity were not much different from Example 1. However, in an environment of hydrochloric acid (HCl), aqueous hydrogen peroxide (H ₂ O ₂ Transparency and conductivity significantly deteriorated in the environment of (3).
In Comparative Example 3, a coating of Pd having a standard electrode potential higher than Ag, which is a nucleus metal, was formed on the surface of the Ag fine particles, and thereafter, the standard electrode potential was higher than Ag and higher than Pd. Noble Au was also deposited to form a film, so that a good coating layer could not be obtained, and the transparency and conductivity were lowered in an environment of hydrochloric acid (HCl) in a hydrogen peroxide solution (H ₂ O ₂ A) significantly worse under the environment.
[0097]
[Example 2]
The Pd-coated Au-coated Ag colloidal dispersion (D) obtained in Example 1 was filtered and washed, and then dried at 100 ° C. to obtain Pd-coated Au-coated Ag fine particles. To 200 g of the Pd-coated Au-coated Ag fine particles, 4 g of sebacic acid, 2 g of triethanolamine, 80 g of butyl cellosolve, and 20 g of resole resin were added and preliminarily mixed with a planetary mill, and then kneaded with three rolls to obtain a conductive adhesive material. Was prepared.
[0098]
Then, using this conductive adhesive material, a 200 μm-wide line and a 40 μm-space test pattern are printed on a BT resin substrate with a screen printer, and then dried and cured at 160 ° C. to form a conductor pattern. did.
An energization test was performed on the substrate on which the conductive wire pattern was formed.
In this energization test, a 10 V DC voltage was applied to the conductor pattern on the substrate for 1000 hours at a temperature of 90 ° C. and a relative humidity of 90% at a high temperature and high humidity. The specific resistance (Ω · cm) of each conductive wire pattern was measured.
Table 2 shows the test results.
[0099]
[Table 2]

[0100]
According to Table 2, the specific resistance of the conductor pattern was 1 × 10 before the test. ^-5 Ω · cm, and 3 × 10 ^-5 Ω · cm, 3 × 10 after 1000 hours ^-5 Ω · cm, and the change in specific resistance before and after the energization test was slight.
[0101]
[Comparative Example 5]
Example 2 Example 2 was repeated except that the Au-coated Ag colloidal dispersion (E) of Comparative Example 1 was filtered and washed, and then dried at 100 ° C. as the metal-coated metal fine particles. A conductive adhesive material was produced in the same manner as in Example 1, and the same evaluation as in Example 2 was performed.
Table 3 shows the test results.
[0102]
[Table 3]

[0103]
According to Table 3, the specific resistance of the conductor pattern was 1 × 10 before the test. ^-5 Ω · cm, but 5 × 10 ^-1 Ω · cm, and conduction failure due to short circuit occurred after 1000 hours of energization.
[0104]
【The invention's effect】
As described above, according to the metal-coated metal fine particles of the present invention, on the surface of the metal fine particles, the metal (A) whose standard electrode potential is higher than that of the metal fine particles, and the standard electrode potential higher than that of the metal fine particles. Since a coating layer made of a metal (B) having a lower standard electrode potential than the metal (A) is formed, it has excellent transparency, conductivity, antistatic properties, electromagnetic wave shielding properties, and salt resistance. Environmental resistance such as water resistance, acid resistance, oxidation resistance, and ultraviolet resistance can be significantly improved.
[0105]
According to the method for producing metal-coated metal fine particles of the present invention, the metal (A) having a higher standard electrode potential than the metal fine particles is deposited on the surfaces of the metal fine particles, and then the standard electrode potential is higher than the metal fine particles. And the metal (B) having a lower standard electrode potential than the metal (A) is deposited, so that it is excellent in transparency, conductivity, antistatic property, electromagnetic wave shielding property, salt water resistance and acid resistance. In addition, metal coated metal fine particles having significantly improved environmental resistance such as oxidation resistance and ultraviolet resistance can be easily produced.
[0106]
According to the paint for forming a transparent conductive film of the present invention, since it contains the metal-coated metal fine particles of the present invention, it has excellent transparency, conductivity, antistatic property, electromagnetic wave shielding property, salt water resistance, and acid resistance. , Environmental resistance such as oxidation resistance and ultraviolet resistance can be remarkably improved.
[0107]
According to the conductive adhesive material of the present invention, since the metal-coated metal fine particles of the present invention are contained, the conductive adhesive material is excellent in conductivity and environmental resistance such as salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance. Can be significantly improved.
[0108]
According to the transparent conductive film of the present invention, since the transparent conductive layer formed by applying the transparent conductive film forming paint of the present invention is provided, it has excellent transparency, conductivity, antistatic property, and electromagnetic wave shielding property. In addition, environmental resistance such as salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance can be significantly improved.
[0109]
According to the display device of the present invention, since the transparent conductive film of the present invention is formed on the display surface, the display surface is excellent in transparency, conductivity, antistatic property, electromagnetic wave shielding property, and the display surface Environmental resistance such as salt water resistance, acid resistance, oxidation resistance, and ultraviolet resistance can be significantly improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a metal-coated metal fine particle of one embodiment of the present invention.
[Explanation of symbols]
1 Fine metal particles
2 (first) coating layer
3 (second) coating layer

Claims (12)

On the surface of metal fine particles,
A coating comprising a metal (A) having a noble standard electrode potential from the metal fine particles and a metal (B) having a noble standard electrode potential than the metal fine particles and having a lower standard electrode potential than the metal (A). Metal-coated metal fine particles having a layer formed thereon. The coating layer is formed on a part of the surface of the metal fine particles, and has a first coating layer made of a metal (A) having a higher standard electrode potential than the metal fine particles, and the first coating on the surface of the metal fine particles. And a second coating layer formed of a metal (B) which is formed in a portion excluding the layer and has a nobleer standard electrode potential than the metal fine particles and a lower standard electrode potential than the metal (A). The metal-coated metal fine particles according to claim 1, wherein: The metal-coated metal fine particles according to claim 2, wherein the metal (A) and / or the metal (B) is composed of two or more metals. 4. The metal-coated metal fine particles according to claim 1, wherein the metal fine particles have an average particle size of 2 to 200 nm. Depositing a metal (A) having a noble standard electrode potential from the metal fine particles on the surface of the metal fine particles;
Next, a method for producing metal-coated metal fine particles, comprising depositing a metal (B) having a standard electrode potential nobler than the metal fine particles and a standard electrode potential lower than the metal (A). The method for producing metal-coated metal fine particles according to claim 5, wherein the metal (A) and / or the metal (B) comprises two or more metals. 7. The method for producing metal-coated metal fine particles according to claim 5, wherein the average particle diameter of the metal fine particles is 2 to 200 nm. A paint for forming a transparent conductive film, comprising the metal-coated metal fine particles according to any one of claims 1 to 4. A conductive adhesive material comprising the metal-coated metal fine particles according to any one of claims 1 to 4. A transparent conductive film comprising a transparent conductive layer formed by applying the transparent conductive film forming paint according to claim 8. The transparent conductive film according to claim 10, wherein an anti-reflection layer is formed on one or both main surfaces of the transparent conductive layer. A display device, wherein the transparent conductive film according to claim 10 is formed on a display surface.

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