JP2000151181A - Corrosion resistant antibacterial conductive film and treating liquid therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a conductive film having high corrosion resistance using inexpensive metallic fine particles by providing an underlying conductive layer and an overlying silica layer containing a biganidyl group. SOLUTION: Ethylsilicate is dissolved into ethanol and added with water and nitric acid and then it is aged while stirring to hydrolyzes ethylsilicate partially. A solution containing the partially hydrolyzed ethylsilicate is added with alkoxy silane containing a biganidyl group to prepare a treating liquid. A glass substrate preheated in an oven is set in a spin coater and turned and the prepared metal colloid is dripped thereon. Subsequently, it is preheated again in the oven and turned while dripping a treating liquid added with alkoxy silane containing a biganidyl group, Thereafter, it is heated in the oven to form a transparent conductive film having two layer structure of underlying metal fine particle layer and overlying silica layer containing a biganidyl group on the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for imparting an antistatic property and an electromagnetic wave shielding property to an image display section of various image display devices such as a TV, a CRT of a computer, and a CRT. The present invention relates to a treatment liquid capable of imparting corrosion resistance and antibacterial property and, in some cases, even better anti-glare properties to a conductive film made of metal fine particles, and a conductive film formed using the treatment liquid. The treatment liquid of the present invention can further be used to improve the corrosion resistance of metals such as aluminum, and at the same time, impart antibacterial properties.

[0002]

2. Description of the Related Art A two-layer film in which an upper layer made of a transparent film having a low refractive index (for example, a siliceous film) is provided on a lower layer made of a transparent conductive film having a high refractive index is used for a CRT of a TV or a CRT of a computer. It is known that antistatic properties and anti-glare properties (prevention of reflection of external light) can be imparted to a film. The above-mentioned two-layer film in which a transparent conductive film is formed from a semiconductor fine powder such as ITO (tin-doped indium oxide) or ATO (antimony-doped tin oxide) is disclosed in, for example, JP-A-5-290634,
Nos. 12920 and 6-234552.

In recent years, electromagnetic waves emitted from a cathode ray tube or a CRT have an adverse effect on the human body, malfunctions of a computer due to external electromagnetic waves, and the like have become problems, and standards for low-frequency leakage electromagnetic waves have been established in various countries. for that reason,
It is required to provide an electromagnetic wave shielding property to a cathode ray tube or a CRT. In order to provide electromagnetic wave shielding, a conductive film with a low surface resistance of the order of 10 ² to 10 ³ Ω / □ is used.
It must be formed on the surface of a cathode ray tube or CRT that is a substrate. In the two-layer film described above, it is difficult to achieve such low resistance because the conductivity of the lower transparent conductive film is low.

Therefore, a transparent conductive film below the two-layer film is formed of metal fine particles having an average primary particle diameter of 0.2 μm (200 nm) or less, and in some cases 0.05 μm (50 nm) or less, particularly a metal colloid. Attempts have been made to satisfy all of the electromagnetic wave shielding property, antistatic property and antiglare property by reducing the resistance. For example, JP-A-8-77832
No., 9-115438, 9-331183, 10-74772, 10-
See the respective publications of 154473.

As the metal fine particles, noble metals, especially Ag, Au, Pt, and Pd, and mixtures or alloys thereof (eg, Ag-Pd) are mainly used in consideration of conductivity and corrosion resistance.

In the case of the above two-layer film, first, a metal fine particle dispersion (eg, a metal colloid) is applied to a substrate (eg, a partial hydrolyzate) to form a metal fine particle film containing no binder. Coating solution capable of forming a siliceous film on it
(Eg, a solution containing alkoxysilane or any partial hydrolyzate, or silica sol), and dried to form a siliceous film. Since the coating liquid for the upper layer also penetrates into the voids of the lower metal fine particle film, the metal fine particles are covered with the siliceous material and protected.

[0007]

However, as described above, metal fine particles have a very small particle size and a large specific surface area.
Therefore, among the noble metals, for example, Ag and Pd content of 70% by weight or less, such as Ag-Pd, metal particles of a noble metal having a relatively low corrosion resistance, it is not possible to sufficiently secure the corrosion resistance by coating with a siliceous film, For example, a chemical change occurs in an environment such as an acid, an alkali, or an oxidizing agent, and the appearance changes. As a result, for example, the conductivity is significantly reduced, and the intended function cannot be sufficiently achieved. On the other hand, Au, Pt, Pd and the like are chemically very stable per se and do not cause such a problem of corrosion resistance, but they are very expensive and cause problems in economy. Therefore, there is still a demand for forming a conductive film having high corrosion resistance using inexpensive fine metal particles of Ag or Ag-Pd.

[0008]

Means for Solving the Problems The present inventors include an alkoxysilane containing a biguanidyl group, which has been conventionally used as an antibacterial agent, in a siliceous film forming an upper layer of the above-mentioned two-layer conductive film. Surprisingly, the corrosion resistance of the underlying metal fine particle film is remarkably improved, and the metal fine particles become Ag or Ag.
It has been found that -Pd also does not cause a change in appearance in an acidic, alkaline or oxidizing environment. In addition to the improvement in corrosion resistance, the presence of the biguanidyl group naturally imparts antibacterial properties to the conductive film.

As a result of further study of this effect, the same effect of improving corrosion resistance can be obtained by providing a siliceous coating containing a biguanidyl group-containing alkoxysilane as the uppermost layer of a conventional two-layer film. It has also been found that when the uppermost layer is formed by spray coating, irregularities are formed on the surface of the conductive film, and the antiglare property is further improved.

Further, the improvement of the corrosion resistance by the biguanidyl group-containing siliceous film is not limited to the metal fine particle film, but is also applied to wiring such as Ag and Cu, and also to general metal materials such as aluminum building materials. It turned out that it could be obtained.

The present invention has been completed based on the above findings, and has the following gist. (1) A conductive film having corrosion resistance and antibacterial property, which is a conductive film formed on a substrate, comprising a lower conductive layer and a siliceous layer containing a biguanidyl group as an upper layer. (2) a conductive film according to (1), comprising a lower conductive layer and an upper biguanidyl group-containing siliceous layer; (3) a lower conductive layer, an intermediate siliceous layer, and an uppermost layer; A conductive film according to (1), comprising three layers of a biguanidyl group-containing siliceous layer formed by a spray method and having anti-glare properties in addition to corrosion resistance and antibacterial properties; (4) a cathode ray tube or a display device (5) The conductive film in which the lower conductive layer is made of fine metal particles; (6) The fine metal particles are Ag, Pd 70% by weight or less of Ag-Pd, Au,
(5) a conductive film of (5), which is one or more selected from fine particles of Pt and Pd; (7) the biguanidyl group-containing siliceous layer contains 0.1 to 30 wt. %, Wherein at least one siliceous layer is selected from a fluorine-containing silane coupling agent and a surfactant.
(9) The conductive film according to (5), wherein the siliceous layer containing the additive appears on the surface of the conductive film.

(10) A treatment liquid for imparting corrosion resistance and antibacterial property to a conductor, comprising a hydrolyzable silane compound or a partially hydrolyzed product thereof, and a biguanidyl group-containing alkoxysilane or a partially hydrolyzed product thereof. (11) The above-mentioned processing solution containing 0.1 to 30% by weight of a biguanidyl group-containing alkoxysilane on a solid content basis; (12) Fluorine-containing silane coupling agent and interface (13) The treatment liquid further containing one or more additives selected from activators; (13) applying the treatment liquid to a conductor and drying to form a biguanidyl group-containing siliceous film; Characterized by
A method for imparting corrosion resistance and antibacterial property to a conductor; (14) the above-mentioned method in which the conductor is in the form of a metal fine particle film or a simple metal; (15) the conductor is Ag, Pd 70% by weight or less of Ag-Pd, Au, Pt, P
The above method comprising a metal selected from d, Al, Cu, and Ni.

(16) A method for imparting improved corrosion resistance and antibacterial properties to a metal material, comprising applying the treatment liquid to a metal material and drying to form a siliceous coating containing a biguanidyl group; (17) The method according to (16), wherein the metal material is aluminum.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the processing liquid according to the present invention will be described. This treatment liquid is characterized by containing a hydrolyzable silane compound or a partial hydrolyzate thereof and a biguanidyl group-containing alkoxysilane or a partial hydrolyzate thereof in a solvent, and has a corrosion resistance and an antibacterial property to a conductor or a metal material. It can be used to impart properties.

The hydrolyzable silane compound forms a siliceous film when subjected to hydrolysis and polycondensation, and thus acts as an inorganic film-forming component. The biguanidyl group-containing alkoxysilane also undergoes hydrolysis and polycondensation together and is incorporated into the siliceous coating by a chemical bond. as a result,
When this treatment liquid is applied and the coating film is dried, a siliceous coating film containing a biguanidyl group is formed.

The siliceous coating containing the biguanidyl group has an effect of protecting the substrate or the metal in the lower layer and improving its corrosion resistance, in addition to imparting the antibacterial property caused by the biguanidyl group. That is, compared with a normal siliceous coating, a siliceous coating containing a biguanidyl group shows higher corrosion resistance. Although the reason is not clear, it is considered that the biguanidyl group having as many as five> NH groups may efficiently capture an acid or a metal that becomes a corrosive substance.

Examples of the hydrolyzable silane compound usable in the present invention include tetraalkoxysilane (= alkyl silicate), trialkoxymonoalkyl or monoarylsilane, dialkoxydialkyl or diarylsilane. The alkoxy and alkyl groups of these silanes preferably have 4 or less carbon atoms. Preferred hydrolyzable silane compounds are methyl silicate,
Alkyl silicates such as ethyl silicate and butyl silicate.

The biguanidyl group-containing alkoxysilane is
In the alkoxysilane having an alkyl group or an aryl group, any compound in which at least one alkyl group or an aryl group is substituted with a biguanidyl group may be used. As the biguanidyl group-containing alkoxysilane that is preferably used in the present invention, a compound represented by the following formula and an acid addition salt thereof are exemplified.

X ¹ X ² X ³ SiY ¹ NHC (= NH) NHC (= NH) NHZ (1) In the above formula, X ^{1 to} X ³ are each a C _{1 to} C ₅ alkyl group or C ₁
Means -C ₅ alkoxy group, at least one of X ¹ to X ^3,
Preferably two or more of C ₁ -C ₅ alkoxy group (e.g., methoxy, ethoxy, etc.) and, Y ¹ means a C ₁ -C ₂₀ alkylene group, Z is hydrogen, C ₁ -C ₂₀ alkyl A phenyl group (a phenyl group may be substituted with a group selected from a halogen, an alkyl group, a fluoroalkyl group and an alkoxy group).

As a specific example of such a biguanidyl group-containing alkoxysilane, a compound represented by the following formula is exemplified. (C ₂ H ₅ O) ₃ Si (CH ₂ ) ₃ NHC (= NH) NHC (= NH) NHZHCl Z is phenyl, p-chlorophenyl, p-methylphenyl,
It means p-trifluoromethylphenyl, n-propyl or n-octyl, particularly preferably p-chlorophenyl.

As the solvent, a water-miscible organic solvent such as alcohol and ketone is preferable. Preferred solvents are alcohols including methanol, ethanol, isopropanol, methoxyethanol, ethoxyethanol and the like. One or more solvents can be used.

When the above-mentioned two types of silane compounds, ie, the hydrolyzable silane compound and the biguanidyl group-containing alkoxysilane, are dissolved in this solvent, the treatment liquid used in the present invention is obtained. In addition, any silane compound can also use the mixture of 2 or more types, respectively.

The ratio of the two is preferably within a range in which the amount of the alkoxysilane having a biguanidyl group is 0.1 to 30% by weight based on the total amount thereof. If the proportion is 0.1% by weight or less, the intended effects of improving corrosion resistance and imparting antibacterial properties cannot be sufficiently obtained. On the other hand, if the amount of the biguanidyl group-containing alkoxysilane exceeds 30% by weight, the amount of silanol required for the siloxane bond is reduced, so that the film strength is reduced and defects in the film are likely to occur. This ratio is more preferably 0.1-20
% By weight.

In this treatment solution, in addition to the above two types of silane compounds, an acid serving as a hydrolysis catalyst (eg, nitric acid, hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, etc.) to promote film formation. Or a small amount of water required for hydrolysis. However, if these are added in large amounts, the stability of the solution will be significantly reduced, and it will be easy to gel immediately during storage.
The amount should be chosen carefully.

In order to further promote film formation, it is advantageous to partially hydrolyze the silane compound in the processing solution in advance. That is, one or both of the hydrolyzable silane compound and the biguanidyl group-containing alkoxysilane can be present in the treatment liquid in a state of a partial hydrolyzate thereof. In that case, it is preferable to partially hydrolyze a large amount of the hydrolyzable silane compound, and the biguanidyl group-containing alkoxysilane may or may not be partially hydrolyzed.

Such a treatment liquid of the present invention can be produced as follows. For example, first a suitable solvent
Dissolve a hydrolyzable silane compound (e.g., methyl silicate or ethyl silicate) in (e.g., methanol or ethanol), add a small amount of water and an acid (e.g., nitric acid), maintain at an appropriate temperature, and add Is partially hydrolyzed. The heating conditions are preferably selected so that the hydrolysis proceeds slowly. For example, the temperature can be in the range of 5 to 70 ° C., and the hydrolysis can be advanced by heating for about 1 to 10 hours. Thereafter, when a biguanidyl group-containing alkoxysilane is added and dissolved, a treatment liquid of the present invention containing a partially hydrolyzate of a hydrolyzable silane compound and a biguanidyl group-containing alkoxysilane is obtained.

In the above-mentioned method, if the biguanidyl group-containing alkoxysilane is added to and dissolved in the solution from the beginning, it can be partially hydrolyzed together during the next heating. Thus, the treatment liquid of the present invention containing both the hydrolyzable silane compound and the biguanidyl group-containing alkoxysilane in a partially hydrolyzed state is obtained.

The concentration of the solid content in the processing solution of the present invention may be selected so as to obtain a solution having an appropriate viscosity according to the purpose of use and the desired film thickness. The viscosity of the liquid varies depending on the degree of hydrolysis of the silane compound. For example, when used for a metal fine particle film as described later, a liquid having a relatively low viscosity (for example, about 0.5 to 1.5 cps) is preferable so as to easily penetrate. On the other hand, when directly applying to a metal material, a liquid having a higher viscosity can be used satisfactorily, which may increase the film forming efficiency.

This treatment liquid may further contain one or more additives selected from a silane coupling agent containing fluorine and a surfactant, as the case may be. This imparts water repellency to the siliceous coating formed from the treatment liquid, making it more difficult for stains to adhere and for the fingerprints to be less likely to adhere. Therefore, the image display unit of the display device can be held more clearly. Further, the corrosion resistance is further improved.

The silane coupling agent containing fluorine may be, for example, a silane coupling agent containing a trifluoromethyl group. A specific example of such a silane coupling agent is 2-trifluoromethylethyl trialkoxysilane (eg, 2-trifluoromethylethyl trimethoxysilane). The fluorine-containing surfactant preferably has a perfluoroalkyl group, preferably a perfluoroheptyl or perfluorooctyl group. Specific examples include perfluorooctanoic acid,
Perfluorooctanoic acid amide. When these are added, their amounts are each 0.1 to 30% by weight, in particular 0.1 to 20% by weight, based on the total amount of solids. 2
When adding more than one kind, it is preferable that the total amount be in this range.

The treatment liquid of the present invention can form a siliceous coating containing a biguanidyl group, and this coating is excellent in transparency, high in hardness, resistant to scratches, and low in reflectivity. In addition to its properties, it has antibacterial properties due to the biguanidyl group. The present inventors have found that this coating is further excellent in corrosion resistance, that is, has an action of improving the corrosion resistance of the substrate. Therefore, the treatment liquid of the present invention can be applied to various conductors and metal materials in order to enhance corrosion resistance and impart antibacterial properties.
Examples of such a material include a conductive film made of metal fine particles,
In particular, the above-mentioned transparent conductive film having a two-layer structure, various wiring layers (eg,
On printed wiring boards) and metal materials for various applications
(Eg, aluminum materials for building materials and other uses).

When applied to a transparent conductive film composed of metal fine particles, first, a metal fine particle layer to be a conductive layer is formed on an appropriate substrate. Examples of suitable substrates include, as mentioned above, TVs and computer cathode ray tubes and CRTs, as well as liquid crystals, E
It is an image display unit of various image display devices such as L and plasma. However, the substrate is not limited to this.
The metal fine particle layer can be formed by applying a dispersion of metal fine particles (that is, a metal colloid) to a substrate and drying.

The average primary particle diameter of the metal fine particles in the metal colloid used for coating is preferably 20 nm or less, more preferably 15 nm or less, particularly preferably 10 nm or less.
When the average primary particle diameter of the metal fine particles is larger than 20 nm, the transparency of the film tends to decrease. The metal species of the metal fine particles is not particularly limited, but a noble metal is generally used in view of conductivity and corrosion resistance in the state of ultrafine particles. Preferred metal species are Ag, up to 70% by weight of Ag-Pd, Au, Pt, and
One or more of Pd. Of these, especially
Ag and Ag-Pd (Ag 70 wt% or less) are preferred. Although Ag and Ag-Pd are relatively inexpensive, they have the disadvantage that they have poor corrosion resistance and are liable to discolor in a normal environment (which also reduces their conductivity), but the present invention overcomes this disadvantage. This is because it can be done.

Since the metal colloid is generally prepared by reducing a metal salt in an aqueous solution to a metal with a suitable reducing agent in the presence of a protective colloid, a large amount of the protective colloid is used.
(Hydrophilic colloids such as water-soluble polymers).
This is because the protective colloid is usually required to stably disperse the hydrophobic metal fine particles in water. However, when a conductive film is formed from such a metal colloid, the protective colloid of an organic substance having no conductivity interferes with the conductivity, so that the baking is performed at a high temperature (for example, 350 ° C. or higher) at which decomposition and disappearance of the organic substance occur. In many cases, sufficient conductivity cannot be obtained unless the above is performed. On the other hand, such a high baking temperature causes, for example, when a transparent conductive film is formed on a cathode ray tube or a CRT tube of a TV or a computer, the phosphor in the cathode ray tube falls off, the dimensional accuracy is reduced, and the vacuum balance due to gas generation is reduced. It cannot be used because of changes and corrosion of the electron gun.

As a method for producing a metal colloid without using a protective colloid, a method announced by Carey Lea in 1889
(M. Carey Lea, American J
own of Science, 37:49
1, 1989). In this method, an aqueous solution of a reducing agent containing citrate ions and ferrous ions (that is, an aqueous solution of ferrous sulfate) is prepared by mixing an aqueous solution of sodium citrate and an aqueous solution of ferrous sulfate. In this method, a silver colloid is obtained by mixing an aqueous solution of a reducing agent with an aqueous solution of silver nitrate to reduce silver nitrate. Since the citrate ion stabilizes the colloid adsorbed on the silver fine particles, the silver colloid is stably maintained without adding a protective polymer colloid. This method uses an aqueous solution of another metal salt, particularly a noble metal salt, instead of an aqueous solution of silver nitrate,
It can also be used to produce other metal colloids.

A relatively low temperature such as a cathode ray tube (eg, 250
When it is necessary to perform baking at a temperature of 200 ° C. or lower, preferably 200 ° C. or lower, it is preferable to use a metal colloid containing no protective colloid obtained by the above-mentioned Carey Lea method. On the other hand, if the substrate withstands high-temperature baking at, for example, 350 ° C. or higher, the required conductivity can be obtained even if a metal colloid containing a large amount of protective colloid is used.

In the method of Carey Lea described above, the step of mixing the aqueous solution of the reducing agent and the aqueous solution of the metal salt to precipitate the metal is performed in an atmosphere substantially free of oxygen (eg, nitrogen,
(In the atmosphere of inert gas such as rare gas)
This is preferable because the stability of the metal colloid is further increased. More preferably, the step of mixing the aqueous solution of sodium citrate and the aqueous solution of ferrous sulfate is also performed in the same atmosphere.

The metal colloid obtained by the above method is recovered by an appropriate method such as sedimentation, filtration, centrifugation and the like, and subjected to an appropriate desalting treatment (eg, ion exchange, dialysis, washing with an aqueous solution of sodium nitrate). After that, redisperse in a suitable medium (eg, water and / or a water-miscible organic solvent such as alcohol).
(Repulp) and used for coating.
At this time, if an organic solvent having a relatively low boiling point is used, the drying time after coating is reduced. The content of the metal fine particles in the metal colloid varies depending on the desired film thickness and the average primary particle diameter of the metal fine particles, but is generally about 0.15 to 0.6% by weight. The metal colloid may contain a small amount of an additive for improving stability. Examples of such additives include surfactants, especially fluorinated surfactants, and polyhydric alcohols and their monoalkyl ethers.

The application of the metal colloid is carried out by a suitable method such as spin coating, and then, if necessary, the coating is dried by heating. The substrate may be preheated in advance to facilitate drying. The thickness of the conductive layer composed of the formed metal fine particles is 10 to 50 nm in order to obtain sufficient transparency and conductivity.
Is preferably within the range.

The treatment liquid according to the present invention is applied on the metal fine particle layer. This coating may be performed by an appropriate method such as spin coating. In the case of spin coating, metal colloid is first dropped using one spin coater,
By drying to form a metal fine particle layer and then dropping the treatment liquid of the present invention, the coating operation can be performed efficiently even with a two-layer film. After the application, the coating is generally cured by heating (baking) to form a siliceous coating containing a biguanidyl group. The baking temperature may be 140 ° C. or higher, and the upper limit is selected according to the type of the substrate.

A part of the treatment liquid of the present invention applied on the metal fine particle layer penetrates into the gaps between the particles of the metal fine particle layer and serves as a binder for binding the metal fine particles. The film strength of the layer is significantly improved. The remaining treatment liquid that has not penetrated accumulates on the metal fine particle layer to form an upper siliceous film. Since the lower metal fine particle layer has a high refractive index and the silica upper layer has a low refractive index, this two-layer film has low reflectivity, imparts anti-glare properties to the substrate, and improves the visibility of images. . For this purpose, the thickness of the silica upper layer is preferably about 10 to 150 nm.

In the present invention, since the upper siliceous material contains a biguanidyl group, the conductive film is further provided with antibacterial properties and corrosion resistance. That is, propagation of bacteria and mold on the surface of the substrate can be prevented, and the substrate can be kept clean. At the same time, for example, even when the conductive layer is made of metal fine particles that easily discolor in an ordinary environment, such as Ag or Ag-Pd of Pd 70% by weight or less, it is necessary to prevent discoloration of the conductivity and a decrease in the conductivity accompanying the discoloration. Can be.

When a silica-based uppermost layer having a fine uneven surface is formed on the two-layer film by a spray method to form a three-layer structure, light reflected on the surface is scattered, so that the antiglare property is further improved. . Further, in the case of using only the two-layer film, the color tone of the image may slightly change, but such a color change can be eliminated because the reflection spectrum is flattened. The thickness of this top layer may be much smaller than the underlying siliceous layer,
It may also be thicker. There is no particular limitation on the thickness as long as the total thickness of the lower siliceous layer does not exceed 200 nm.

When the uppermost layer of silica having the fine uneven surface is formed, the uppermost layer is preferably formed by using the treatment liquid of the present invention. The presence of biguanidyl groups in the uppermost layer appearing on the surface results in higher antibacterial and corrosion-resistant effects than when they are present below. In that case, the underlying siliceous coating (the siliceous layer formed as the upper layer of the conductive layer) does not need to be formed from the treatment liquid of the present invention, and is a normal hydrolyzable silane compound containing no biguanidyl group-containing alkoxysilane. (Eg, alkoxysilane) or a solution of a partial hydrolyzate thereof or a film formed using a silica sol (ie, a siliceous film containing no biguanidyl group).

That is, in a preferred embodiment of the conductive film having a three-layer structure having the uppermost layer, the uppermost siliceous film having fine irregularities formed by the spray method is formed from the treatment liquid of the present invention. This uppermost layer becomes a siliceous layer containing a biguanidyl group. In that case, an ordinary siliceous layer containing no biguanidyl group is sufficient for the intermediate siliceous layer sandwiched between the lower conductive layer and the uppermost layer. The uppermost layer of the siliceous coating containing a biguanidyl group can sufficiently impart antibacterial properties and corrosion resistance to the three-layered conductive film. Even if the uppermost layer contains a biguanidyl group, there is no adverse effect on the antiglare property. Of course, it is also possible to include a biguanidyl group in the siliceous coating of the intermediate layer.

The treatment liquid according to the present invention is applied directly to a conductor or a metal material to form a siliceous film containing a biguanidyl group thereon, whereby the conductor or the metal material is added with corrosion resistance. Antibacterial properties can be imparted. The conductor is, for example, a wiring or an electrode. As the metal species, non-noble metals such as Al, Cu, and Ni can be used in addition to the noble metals exemplified for the metal fine particles. An example of a metal material is aluminum. Aluminum is generally used unpainted, but, as is well known, is an amphoteric metal, so that corrosion proceeds in an acidic or alkaline environment.
However, when a siliceous film containing a biguanidyl group is formed on the surface of aluminum using the treatment liquid of the present invention,
Corrosion of aluminum in acidic, alkaline or oxidizing environments can be significantly suppressed. Therefore, for example, corrosion resistance can be imparted together with antibacterial properties to aluminum used for many applications including building materials.

For this purpose, it is preferable to form a siliceous coating containing a biguanidyl group with a thickness in the range of 30 to 100 nm. This thickness is very thin compared to painting. The coating method and baking temperature (preferably 140 ° C or higher)
What is necessary is just to select suitably according to the shape and material of a base material.

[0048]

EXAMPLES (Example 1) In this example, the preparation of a processing solution according to the present invention will be exemplified. 1.0 g of ethyl silicate (= tetraethoxysilane) was dissolved in 100 g of ethanol, and 4.0 g of water and 0.15 g of 60% nitric acid as a hydrolysis catalyst were added to this solution.
And aged at 40 ° C. for 4 hours with stirring to partially hydrolyze the ethyl silicate. 0.1 g of a biguanidyl group-containing alkoxysilane [formula: (C ₂ H ₅ O) ₃ Si (CH ₂ )] is added to the solution containing the ethyl silicate partial hydrolyzate.
₃ NHC (= NH) NHC (= NH) NHZ · HCl, wherein Z is p-chlorophenyl], and the concentration is adjusted by adding a suitable solvent to obtain 10% by weight of biguanidyl based on ethyl silicate. A treatment liquid according to the present invention containing a group-containing alkoxysilane was prepared and used for coating.

In the same manner, a treatment solution in which the ratio of a biguanidyl group-containing alkoxysilane to ethyl silicate was changed, and a methyl silicate oligomer (trimer to pentamer, 51 manufactured by Mitsubishi Chemical) instead of ethyl silicate (solvent was methanol ) Or butyl silicate (= tetrabutoxysilane) (solvent is butanol) was also prepared.

Further, a treating solution to which no alkoxysilane containing a biguanidyl group was added (that is, a solution of a partial hydrolyzate of methyl silicate, ethyl silicate or butyl silicate) was similarly prepared.

(Example 2) This example illustrates the formation of a conductive film having a two-layer structure in which a siliceous film is formed from the treatment liquid of the present invention on a lower conductive layer made of metal fine particles.

An aqueous solution was prepared by separately dissolving silver nitrate, palladium nitrate, chloroauric acid and platinum (II) chloride in water. Separately, granular ferrous sulfate was dissolved in an aqueous sodium citrate solution in a stream of nitrogen gas to prepare a reducing agent aqueous solution containing citrate ions and ferrous ions.
While maintaining the nitrogen gas flow, one of the aqueous metal solutions was added to the aqueous reducing agent solution at a temperature of 35 to 95 ° C. with stirring, and the metal was reduced by continuing the stirring to obtain a metal colloid. Ag-Pd
In the case of, the aqueous solution of the Ag salt and the aqueous solution of the Pd salt were mixed at a predetermined ratio, and then added to the aqueous solution of the reducing agent. The obtained metal colloid was allowed to stand at room temperature, the precipitated metal fine particles were separated by decantation, and the separated product was added to deionized water to form a dispersion, which was then desalted by dialysis, and then deionized water was added. It was repulped to form a metal colloid having a metal content of 0.1 to 10% by weight and used for coating.

A glass substrate of 100 mm × 100 mm × 2.7 mm thickness was preheated to 40 ° C. in an oven, set on a spin coater and rotated at 150 rpm, and 2 cc of the metal colloid prepared above was added dropwise. After rotating for 90 seconds, it was preheated again to 40 ° C. in an oven, and 2 cc of the treatment liquid to which the biguanidyl group-containing alkoxysilane prepared in Example 1 was added was added dropwise.
Again rotated for 90 seconds. Then in an oven at 160 ° C
For 20 minutes to form a transparent conductive film having a two-layer structure comprising a metal fine particle layer in the lower layer and a siliceous layer containing the biguanidyl group in the upper layer. For comparison, a transparent conductive film in which the siliceous layer did not contain a biguanidyl group was also formed.

When the cross section of the obtained transparent conductive film was observed with a scanning electron microscope (SEM), it was confirmed that the lower layer was a two-layer film composed of a fine metal particle film and the upper layer a silica film. Table 1 also shows the results of measuring the film thickness of the upper layer and the lower layer from the SEM photograph and the results of measuring the film characteristics of the two-layer film as follows.

Surface resistance: Measured by a four-point probe method (Loresta AP: manufactured by Mitsubishi Yuka). Visible light transmittance: The light transmittance was measured at a wavelength of 550 nm using a self-recording spectrophotometer (U-4000: manufactured by Hitachi, Ltd.). In addition, the visible light transmittance showed the measured value at 550 nm. In the case of the metal fine particles of the present invention, it has been experimentally confirmed that the visible light transmittance at 550 nm substantially coincides with the total visible light transmittance.

Corrosion resistance: A substrate having a transparent conductive film was immersed in 1N hydrochloric acid or 2% hydrogen peroxide solution at room temperature for 24 hours.
After the time, it was taken out and the appearance was visually observed, and judged by the presence or absence of discoloration. 〇 indicates no discoloration, △ indicates slight change, and X indicates obvious discoloration.

Antibacterial properties: After immersion in 1N hydrochloric acid for 24 hours (after corrosion resistance test) and without immersion (before corrosion resistance test)
2. Escherichia coli 3.0 × 10 ⁵ on transparent conductive film of two types of substrates
0.1 mL of a bacterial solution containing the cells / mL was added dropwise, and the solution was allowed to stand at 30 ° C. for 16 hours. Then, the bacterial solution was collected, and the number of bacteria in the solution (converted to the number per mL) was determined.

[0058]

[Table 1]

As can be seen from Table 1, if the upper siliceous layer does not contain a biguanidyl group, there is no antibacterial activity.
(Bacterial count before and after the corrosion resistance test was 3.0
× is increasing from 10 ^5, later corrosion test bacteria count slightly more) of the course of that, the fine metal particles is poor corrosion resistance in Ag and Ag-Pd, dilute hydrochloric acid and either dilute aqueous hydrogen peroxide Discoloration occurred even in the environment.

On the other hand, when the siliceous layer contains a biguanidyl group according to the present invention, not only can the antibacterial property be obtained, but also, unexpectedly, the corrosion resistance can be remarkably improved, and the metal fine particles can be made of Ag and Ag-Pd. In both cases, no discoloration was observed after immersion in both dilute hydrochloric acid and dilute hydrogen peroxide solution for 24 hours. Therefore, it is presumed that discoloration is prevented for a long time in the atmosphere. When the antibacterial properties were examined after the corrosion resistance test, the same excellent antibacterial properties as before the corrosion resistance test were shown. Therefore, it is presumed that the long-term durability of the antibacterial property is improved with the improvement of the corrosion resistance. From the above, according to the present invention, Ag or Ag
−Pd can provide long-lasting corrosion resistance (anti-discoloration) and antibacterial properties to a transparent conductive film using relatively inexpensive metal fine particles called Pd. Electromagnetic wave shielding effect) can be prevented from deteriorating. It can also be seen that the presence of the biguanidyl group has virtually no effect on conductivity or visible light transmittance (transparency).

Example 3 In this example, an intermediate siliceous layer and a biguanidyl group-containing siliceous layer having fine surface irregularities formed by spraying were formed on the uppermost layer on the fine metal particle layer. An example of forming a transparent conductive film having a three-layer structure will be described.

A glass substrate of 100 mm × 100 mm × 2.7 mm thickness was preheated to 40 ° C. in an oven, set on a spin coater and rotated at 150 rpm, and 2 cc of the metal colloid prepared in Example 2 was dropped. After rotating for 90 seconds, the mixture was preheated again to 40 ° C. in an oven, and 2 cc of the treatment liquid prepared in Example 1 to which the biguanidyl group-containing alkoxysilane was not added was added dropwise and again rotated for 90 seconds. Thereafter, the substrate was further preheated to 70 ° C. in an oven, and 5 cc of the treatment liquid prepared in Example 1 to which the alkoxysilane having a biguanidyl group was added was sprayed for 10 seconds. Finally, the substrate was heated to 160 ° C. in the oven at 160 ° C. By heating for a minute, a desired transparent conductive film having a three-layer structure was formed on the substrate.

The surface resistance, visible light transmittance, corrosion resistance, and antibacterial property of this transparent conductive film were examined in the same manner as in Example 2.
Further, the antiglare property of this transparent conductive film was visually inspected based on the clarity of the reflection of the face. 〇 is blurred, and × is clearly reflected. Table 2 shows the results. Although the film thickness is not shown in Table 2, the thickness of the metal fine particle layer and the intermediate layer was substantially the same as the thickness of the metal fine particle layer and the upper layer of Example 2, and the thickness of the uppermost layer was approximately 5 to 80 nm.

[0064]

[Table 2]

As can be seen from Table 2, even if the uppermost layer of the three-layered transparent conductive film to be spray-coated contains a biguanidyl group, the transparent conductive film has antibacterial properties and corrosion resistance without changing the conductivity and transparency. It can be seen that can be given. It can also be seen that the formation of the spray-coated uppermost layer improves the antiglare properties. Although not shown in this table, in the case of the transparent conductive film having a two-layer structure having no uppermost layer by the spray method in Example 2, the anti-glare property is × based on the criteria of this example.
However, even with this two-layered transparent conductive film, the antiglare property is improved as compared with the glass substrate.

(Example 4) In this example, a silica-based coating containing a biguanidyl group (in the case of a two-layer structure, an upper layer in the case of the two-layered transparent conductive film of Example 2 or the three-layered structure of Example 3). In the case of a three-layer structure, the uppermost layer contains a silane coupling agent containing fluorine or a surfactant. The silane coupling agents and surfactants used were as follows.

A: 2-trifluoromethylethyltrimethoxysilane [CF ₃ CH ₂ CH ₂ Si (OCH ₃ ) ₃ ] (silane coupling agent), B: perfluorooctanoic acid amide [C ₇ F ₁₅ CONH ₂ ] (Surfactant), C: perfluorooctanoic acid [C ₇ F ₁₅ COOH] (surfactant)
.

One kind of additive selected from the above is added to a partial hydrolyzate solution of ethyl silicate together with a biguanidyl group-containing alkoxysilane, and 10 wt% of the biguanidyl group-containing alkoxysilane and 5 wt. A treatment liquid containing the additive in a percentage by weight was prepared. Formation of a two-layer or three-layer transparent conductive film and film properties in exactly the same manner as in Example 2 or Example 3 except that the treatment solution containing the biguanidyl group alkoxysilane further contains the above additive. Was investigated. Furthermore, the water repellency and fingerprint resistance of the transparent conductive film were examined as follows. Table 3 shows the test results.

Water repellency: Drops of ion-exchanged water were dropped on the transparent conductive film of the substrate, and it was determined whether or not the droplets slipped when the substrate was inclined at 45 °. 〇 slides down, × does not slide down. Fingerprint resistance: A finger was pressed with a force of 1 kgf for 30 seconds, and it was visually determined whether or not a fingerprint mark remained. 〇 means no mark remains, × means no mark remains.

[0070]

[Table 3]

As can be seen from Table 3, when the siliceous film coming on the surface contains a silane coupling agent containing fluorine or a surfactant in addition to the biguanidyl group,
While maintaining good surface resistance and transmittance, the transparent conductive film can be imparted with water repellency and fingerprint resistance in addition to the corrosion resistance and antibacterial properties of the biguanidyl group.

(Example 5) This example shows an example in which the treatment liquid of the present invention is applied to an aluminum substrate to impart corrosion resistance. A treating solution of the present invention containing a partially hydrolyzed product of methyl silicate and a biguanidyl group-containing alkoxysilane in the same manner as in Example 1 using 5% by weight of a biguanidyl group-containing alkoxysilane with respect to methyl silicate. Was prepared.

An aluminum plate having a size of 100 mm × 100 mm × 2 mm in thickness was immersed in the above-mentioned treatment liquid to apply the treatment liquid, and the coated substrate was placed in an oven and baked at 160 ° C. for 20 minutes. The surface resistance, antibacterial property, and corrosion resistance of this aluminum plate were investigated in the same manner as in Example 2. Regarding the corrosion resistance, in this example, in addition to the 24-hour immersion test in 1N hydrochloric acid, a test under more severe conditions of immersion in a sulfuric acid solution of pH 1 at 70 ° C. for 1000 hours was also performed, and the coated surface was visually observed. Was evaluated. Table 4 shows the test results.

[0074]

[Table 4]

As can be seen from Table 4, aluminum of the substrate corrodes not only in hot sulfuric acid but also in dilute hydrochloric acid. On the other hand, when coated with a siliceous film containing a biguanidyl group according to the present invention, not only dilute hydrochloric acid but also hot Corrosion could be prevented even under the harsh condition of immersion in sulfuric acid for 1000 hours, and it became clear that this siliceous coating had excellent corrosion resistance.

[0076]

The treatment liquid according to the present invention can form a siliceous coating containing a biguanidyl group, and this coating is excellent in transparency, high in hardness, resistant to scratching and low in reflectivity. In addition to having properties inherent to the coating and antibacterial properties due to the biguanidyl group, it also has very good corrosion resistance, and can protect the underlying material from attack by acids, alkalis, oxidizing agents, and the like.

For example, this treatment solution is formed on a low-reflection transparent conductive film having a siliceous layer on the metal fine particle layer (an image display portion of a display device such as a cathode ray tube or a CRT to form an antistatic property, When used for forming a siliceous layer (providing a shielding property and an antiglare property), or when the uppermost siliceous layer having fine surface irregularities is formed thereon by a spray method, the uppermost layer is formed. By using this, even if the metal fine particles in the lower layer are made of a material such as Ag or Ag-Pd that is liable to change color, it is possible to prevent the metal fine particles from being changed in color and, consequently, from lowering the conductivity. In addition, because of its excellent corrosion resistance, the antibacterial effect of the biguanidyl group is maintained. Further, when this treatment liquid contains a surfactant containing fluorinated or a silane coupling agent, the transparent conductive film is provided with water repellency and anti-fingerprint adhesion, and in addition to preventing dust adhesion due to an antistatic effect. Thus, the dirt prevention effect is further improved by water repellency and prevention of fingerprint adhesion. This effect is not limited to the case of a transparent conductive film, but can be applied to the case where corrosion resistance and antibacterial properties are imparted to a conductor such as a wiring layer or a metal material (eg, aluminum material) used for building materials and other uses. Is also obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) G09F 9/30 335 H01J 5/08 5E321 H01J 5/08 9/20 A 9/20 29/88 29/88 G02B 1/10 A (72) Inventor Daisuke Shibuta 1-297 Kitabukuro-cho, Omiya-shi, Saitama F-term in Mitsubishi Materials Corporation Research Laboratory (reference) 2K009 CC14 CC42 CC47 DD02 EE03 EE05 4J038 DL051 DL081 GA09 JA37 JB13 JC13 JC35 JC35 KA03 KA09 MA07 NA03 NA05 PB09 PC02 5C028 AA01 AA02 AA03 AA04 AA05 AA07 AA10 5C032 AA02 DD02 DE01 DE03 DG01 DG02 5C094 AA01 AA31 AA38 BA34 DA13 EA00 FB12 HA08 5E321 AA04 BB23 BB53 GG01

Claims (17)

[Claims] 1. A conductive film formed on a substrate, comprising a lower conductive layer and a siliceous layer containing a biguanidyl group as an upper layer, wherein the conductive film has corrosion resistance and antibacterial properties. Conductive film. 2. The metal oxide conductive film according to claim 1, comprising a lower conductive layer and a biguanidyl group-containing siliceous layer immediately above the lower conductive layer. 3. A lower conductive layer, an intermediate siliceous layer,
The conductive film according to claim 1, comprising three layers of a biguanidyl group-containing siliceous layer formed by a spray method on the uppermost layer, and having anti-glare properties in addition to corrosion resistance and antibacterial properties. 4. The image forming apparatus according to claim 1, wherein the substrate is a cathode ray tube or an image display unit of a display device.
The conductive film according to the above item. 5. The conductive film according to claim 1, wherein the lower conductive layer is made of metal fine particles. 6. An Ag-containing metal fine particle containing 70% by weight or less of Ag and Pd.
The conductive film according to claim 5, wherein the conductive film is at least one selected from fine particles of Pd, Au, Pt, and Pd. 7. The biguanidyl group-containing siliceous layer may contain a biguanidyl group-containing alkoxysilane on the basis of solid content of 0.1 to 0.1%.
The conductive film according to any one of claims 1 to 6, wherein the conductive film is formed from a coating liquid for forming a siliceous film containing 30% by weight. 8. The method according to claim 1, wherein at least one siliceous layer contains one or more additives selected from a silane coupling agent containing fluorine and a surfactant. 2. The conductive film according to claim 1. 9. The conductive film according to claim 8, wherein the siliceous layer containing the additive is a layer that appears on the surface of the conductive film. 10. A treatment liquid for imparting corrosion resistance and antibacterial property to a conductor, comprising a hydrolyzable silane compound or a partial hydrolyzate thereof, and a biguanidyl group-containing alkoxysilane or a partial hydrolyzate thereof. A processing solution, characterized in that it is contained therein. 11. The treatment liquid according to claim 10, comprising 0.1 to 30% by weight of a biguanidyl group-containing alkoxysilane on a solid content basis. 12. The treatment liquid according to claim 10, further comprising one or more additives selected from a fluorine-containing silane coupling agent and a surfactant. 13. The conductor according to claim 10, wherein the treatment liquid is applied to a conductor, and dried to form a biguanidyl group-containing siliceous film. And how to impart antibacterial properties. 14. The method according to claim 13, wherein the conductor is in the form of a fine metal particle film or a simple metal. 15. An Ag-P conductor containing Ag and Pd of 70% by weight or less.
The method according to claim 13 or 14, comprising a metal selected from d, Au, Pt, Pd, Al, Cu, and Ni. 16. An improvement to a metal material, characterized in that the treatment liquid according to claim 10 is applied to a metal material and dried to form a silica coating having a biguanidyl group. To impart improved corrosion resistance and antibacterial properties. 17. The method of claim 16, wherein the metal material is aluminum.