JPH07102177A - Electrically conductive film-forming composition - Google Patents

Abstract

PURPOSE:To provide a composition capable of forming such electrically conductive films of low electrical resistance and high transparency as to be 10<2>-10<4>OMEGA in surface resistivity, >=80% in light transmittance and <=6% in haze. CONSTITUTION:A resin 0.5-15mgKOH/g in acid value and/or 0.5-40wt.% in polyalkylene glycol chain content and 8000-150000 in weight-average molecular weight is dissolved in a mixture of a polar solvent (e.g. alcohol) and a nonpolar solvent (e.g. xylene) to prepare a resin solution 5-50wt.% in solid content, and 15-60wt.% of indium oxide powder containing 1 15mol% of tin is then dispersed in 40-85wt.% of this resin solution, thus obtaining the objective composition for forming electrically conductive films.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive film-forming composition which can be used in the fields of electrophotographic recording, transparent electrodes, antistatic, heat ray reflection, surface heating elements and the like. For the sake of convenience, in the following description, the field of the transparent electrode having the most demanding performance will be taken as an example. A transparent electrode circuit can be easily formed by applying or printing the composition of the present invention on an insulator.

[0002]

2. Description of the Related Art Oxide semiconductor transparent films generally have a high transmittance for visible light, and have low resistance and strong film strength. Therefore, transparent electrodes for liquid crystal displays, window materials for solar cells, heat ray reflective films, etc. It is used in various fields such as antistatic film. A typical example of such an oxide semiconductor is indium oxide containing tin (hereinafter referred to as ITO).

As a conventional method for forming a transparent conductive film, a metal or an inorganic material (especially ITO) is vacuum-deposited on an insulator,
A method of attaching by sputtering, ion plating, etc., a method of coating a metal compound solution on a substrate and drying and baking it, a method of treating ITO with a dispersant, and then applying a dispersion liquid dispersed in a resin solution as a paint or ink. Or a method of printing is known.

Vapor deposition and sputtering have been the most widely used film forming methods in the past, but there is a limit to the increase in the area of electrodes, and the target deterioration due to abnormal discharge and the low adhesion efficiency during film formation. Therefore, the effective use efficiency of ITO is very low at 40-55%. Further, when a circuit is drawn by an etching method, there is a disadvantage that most of the ITO attached to the substrate is removed and the facility cost is high.

In the method of coating a metal compound solution on a substrate and baking it after drying, since the baking temperature is high, the material of the substrate is limited, and there is also a drawback that it is difficult to obtain appropriate film characteristics with one coat and one bake. is there.

A dispersion obtained by subjecting ITO powder to a resin solution after surface treatment with a wetting agent or a pigment dispersant, or by dispersing the ITO powder in a nonpolar solvent containing a dispersant and a resin. In the method of forming a conductive film by using as a paint or ink, a dispersant or resin is closely adsorbed on the ITO surface to improve the dispersibility of ITO and
The effect of preventing the agglomeration of O particles is brought about. Moreover, since the circuit can be drawn directly by a technique such as screen printing,
There is no waste of material.

[0007]

However, since a polymer substance such as a dispersant or a resin generally acts as an insulator, when the polymer is densely adsorbed on the ITO surface, an insulating layer is formed to reduce the resistance. Will be difficult. Further, even if the dispersibility of ITO is improved by adsorption of a polymer, the ITO itself has a high specific gravity, so that ITO precipitates during storage to form a hard cake. There is also a problem.

The object of the present invention is to solve the above-mentioned problems, to be applicable to a resin substrate having a low heat resistance, to form a conductive film having a low resistance and a high light transmittance, and being excellent in stability with time during storage. It is to provide a composition for forming a conductive film.

[0009]

The present inventors have used a mixed organic solvent of a polar solvent having a strong affinity with ITO and a nonpolar solvent having a weak affinity, and an acidic functional group is contained in the mixed organic solvent. Alternatively, it was determined that the above object can be achieved by dissolving a resin having at least one of polyalkylene glycol chains and dispersing ITO in the obtained solution.

The gist of the present invention is to provide tin-containing indium oxide (ITO) in a resin solution consisting of a resin having at least one of an acidic functional group and a polyalkylene glycol chain and a mixed organic solvent of a polar solvent and a non-polar solvent. ) A conductive film-forming composition in which a powder is dispersed. This resin has a weight average molecular weight of 8,000 to 150,000, an acid value of 0.5 to 15 mg KOH / g when it has an acidic functional group, and a content of 0 when it contains a polyalkylene glycol chain.
It is 5 to 40% by weight.

In a preferred embodiment, the ITO powder has an Sn content with respect to In of 1 to 15 mol% and an average primary particle size of 0.2.
Ultrafine particles in the range of μm or less, the nonvolatile content of the resin solution is 5 to 50% by weight, and the weight ratio of the polar solvent to the nonpolar solvent of the mixed organic solvent is in the range of 0.5 / 9.5 to 7/3. is there.

The ITO particles used in the present invention are based on In
Sn content is 1 to 15 mol% and average primary particle size is 0.2μ
It is preferably composed of ultrafine particles of m or less, and can be used in an amount of 15 to 60% by weight in the composition (paint or ink) of the present invention. The remaining 40 to 85% by weight is the resin solution.

As the polar solvent having a strong affinity with ITO, a solvent having a hydroxyl group and / or a ketone group such as methanol, ethanol, butanol, diacetone alcohol, diethylene glycol, butyl carbitol, isophorone and cyclohexanone (that is, monovalent) Alternatively, polyhydric alcohols and / or ketone solvents) can be used.

Non-polar solvents having a weak affinity for ITO include aromatic hydrocarbons such as xylene and toluene, alicyclic hydrocarbons such as cyclohexane, and hydrocarbons such as aliphatic hydrocarbons such as hexane and octane. Is mentioned.

In the present invention, a mixed organic solvent containing at least one polar solvent and a nonpolar solvent is used. It is desirable that the polar solvent and the nonpolar solvent have a good compatibility. The mixing ratio of these two kinds of solvents is preferably in the range of 0.5 / 9.5 to 7/3 by weight ratio of polar solvent / nonpolar solvent.

If the proportion of polar solvent is too high, the solvent and IT
The affinity with O is too strong, the adsorption of ITO and polymer (resin) becomes insufficient, and a strong aggregate structure is formed between ITO particles, and the light transmittance of the conductive film and storage stability of ink and paint are stable. Sex decreases. On the other hand, if the proportion of the non-polar solvent is too high, the affinity between the solvent and ITO is weakened and the adsorption of the polymer on ITO increases, and the dispersibility of ITO improves, while an insulating layer is formed on the particle surface. Therefore, it becomes difficult to reduce the resistance.

The resin used in the present invention has a weight average molecular weight of
Acrylic, alkyd, polyamide, polyester, and polycarbonate resins of 8,000 to 150,000 are preferable, and acrylic and polyester resins are particularly preferable.

When the resin contains an acidic functional group, the acidic functional group has an acid value of 0.5 to 15 mgKOH / g, preferably 1.0 to 10 mgKO.
It is present at a rate of H / g. Preferable acidic functional groups are carboxyl group, phosphoric acid group, sulfonic acid group and the like.

When the resin has a polyalkylene glycol chain, the content of the polyalkylene glycol chain is in the range of 0.5 to 40% by weight, preferably 2.0 to 30% by weight. Examples of preferred polyalkylene glycol chains include polyethylene glycol, polypropylene glycol,
Polyethylene glycol alkyl ether, polyethylene glycol phenyl ether, polyethylene glycol alkyl phenyl ether, polypropylene glycol alkyl ether, polypropylene glycol phenyl ether, polypropylene glycol alkyl phenyl ether, polyethylene glycol alkyl amine,
Polyethylene glycol alkylamide, polyethylene glycol glycidyl ether, and the like.

The resin used in the present invention can be produced by a conventional method by using a monomer having an acidic functional group and / or a monomer having a polyalkylene glycol chain as a copolymerization component. For example, in the case of acrylic resin, examples of the acidic functional group-containing monomer include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, 2-methacryloyloxyethylsuccinic acid and 2-methacryloyloxyethylphthalic acid, mono (2-
(Meth) acryloyloxyethyl) acid phosphate, diphenyl-2- (meth) acryloyloxyethyl phosphate and other phosphoric acid (meth) acrylic acid esters and 2-sulfoester (meth) acrylates, and polyalkylene glycol-containing monomers As the above, the above-mentioned monoacrylic acid ester or monomethacrylic acid ester of polyalkylene glycol can be used.

If the weight average molecular weight of the resin is greater than 150,000 or the acid value is greater than 15 mgKOH / g, the amount of resin adsorbed on the ITO surface increases and the surface resistance value increases. When the weight average molecular weight is less than 8000, the resin acts as a pigment dispersant and is closely adsorbed on the ITO surface. As a result, the dispersibility of ITO improves and the light transmittance increases, but
The surface resistance value is still high. Acid value is 0.5mg KO
If it is less than H / g, the resin adsorption to the ITO surface becomes insufficient and the dispersibility of ITO decreases, resulting in a decrease in light transmittance.

The content of polyalkylene glycol chain is 40
If it is more than 10% by weight, the polarity of the resin is strengthened, resulting in poor dispersion of ITO, resulting in a decrease in light transmittance. On the other hand, if it is less than 0.5% by weight, the dispersibility of ITO is remarkably lowered, and the light transmittance is lowered.

The conductive film-forming composition of the present invention can be produced by dissolving the resin in the mixed solvent to prepare a resin solution, and dispersing ITO powder in the resin solution. The ITO powder can be dispersed by a conventional method using a paint shaker, a ball mill, a centri mill, a sand grind mill, or the like. A transparent conductive film is formed by applying or screen-printing this resin composition as a paint or ink on an appropriate substrate, and heating (and curing) if necessary.

The conductive film forming composition of the present invention comprises a resin, I
In addition to TO and a mixed organic solvent, additives such as a curing catalyst, a wetting agent, a dispersant, an antioxidant, and a leveling agent can be further contained if necessary.

[0025]

The composition for forming a conductive film of the present invention comprises an ITO powder in a resin solution containing a resin having at least one of an acidic functional group and a polyalkylene glycol chain and a mixed organic solvent of a polar solvent and a nonpolar solvent. Is dispersed. A conductive film circuit can be formed on an insulating substrate by applying this composition as a paint or printing as an ink.

In the case of a resin containing an acidic functional group, by introducing an acidic functional group such as a carboxyl group, a phosphoric acid group or a sulfonic acid group as a pendant into the resin,
Interaction occurs between the water of crystallization and free water on the surface of the ITO powder, the resin itself becomes a proton conductor, the volume resistance value decreases, and the acidic functional groups of the resin are adsorbed on the adsorption sites on the ITO surface. Prevents the ITO particles from aggregating,
ITO is reduced to primary particles.

On the other hand, in the case of a resin containing a polyalkylene glycol chain, unlike an acidic functional group, a resin containing a polyalkylene glycol chain is used regardless of the presence of water in the air or water of crystallization of ITO powder and free water. Since the ion conductivity is generated as a whole, the volume resistance value of the resin itself is also lowered. In addition, although the dispersibility is weaker than that of the acidic functional group, the hydrophilic group of the polyalkylene glycol chain causes strong hydrophilicity I.
The TO powder is atomized to near the primary particles. Adsorption of resin occurs on the surface of the atomized particles.

When the resin contains both an acidic functional group and a polyalkylene glycol chain, the effects of both are combined and the effect becomes more remarkable.

Further, by using a mixed solvent having different polarities, the amount of resin adsorbed on the ITO surface and the spread of the adsorbed resin can be controlled, and the resin can be partially adsorbed on the ITO surface. The surface of the ITO particles is not completely covered with the resin, and weak crosslinks are formed in the uncoated portions between the ITO particles. Then, this weak bridge is easily cut by stirring or the like, and redispersion of ITO into a fine particle state occurs.

Therefore, during storage, the ITO is stabilized due to the weak crosslinks formed between the ITO particles, sedimentation does not occur, and the temporal stability during storage of the paint or ink is improved.
Then, during coating and printing, the bridges between the ITO particles are cut, and a smooth film is obtained because it behaves as a Newtonian despite being quite viscous.

In the drying / curing process, ITO is used.
A conductive portion is generated due to the proximity of the portions of the particles that are not covered with the resin and the conductivity of the resin, and a reduction in resistance is realized. Further, by improving the dispersibility of the ITO particles, a conductive film having low haze, high light transmittance, and excellent transparency can be obtained. The conductive film forming composition according to the present invention can form a transparent conductive film on a substrate by coating, screen printing, etc., and thus is also used for a resin having relatively low heat resistance, which enables continuous mass production and large area production. Realization is possible. By using the composition of the present invention, the characteristics of the film are
It can be adjusted in the order of 10 ² to 10 ⁴ Ω / □ and within the range of 80 to 90% in light transmittance.

When the resin does not have a polyalkylene glycol chain and has an acidic functional group, the surface resistance value is generally on the order of 10 ³ Ω / □ and the light transmittance is 85% or more. If the resin does not have an acidic functional group and has a polyalkylene glycol chain, the surface resistance value will be on the order of 10 ² Ω / □, the light transmittance will be 80% or more, and the surface resistance value will decrease, but the light transmission The rate will decrease. When the acid value is 0.5 to 15 mgKOH / g and it also has a polyalkylene glycol chain, the surface resistance value is on the order of 10 ² Ω / □ and the light transmittance is
A good result is obtained for both, at 85% or more. Therefore,
The acid value and the amount of polyalkylene glycol chain may be selected according to the required resistance value and light transmittance level.

[0033]

EXAMPLES The present invention will be specifically described below with reference to examples. In the examples, parts are parts by weight unless otherwise specified, and the unit of acid value (mgKOH / g) is omitted. The ITO used in the examples is a powder having a Sn content of 5 mol% with respect to In and an average primary particle diameter of 0.05 μm, and the solvent of the polyester resin solution is a mixed solvent of butanol and xylene. The weight ratio was 2/8.

Example 1 A flask equipped with a reflux tube, a thermometer, a dropping funnel and a stirrer was charged with 60 parts of xylene.
After heating to 90 ℃, 20 parts of styrene, methyl acrylate 1
After adding a mixture consisting of 9.5 parts, 0.5 part of acrylic acid and 2 parts of azobisisobutyronitrile over 4 hours,
The reaction was carried out for a time to obtain a resin solution having a nonvolatile content of 41% by weight, a resin weight average molecular weight of 10,000 and an acid value of 9.7. 50.0 parts of this resin solution, 80.0 parts of ITO, 120.0 parts of a mixed solvent having a butanol / xylene weight ratio of 4/6 and 250.0 parts of glass beads were placed in a 500cc container, and the dispersion state was confirmed by a particle shaker with a paint shaker. While kneading for 5 hours. After kneading, the glass beads were removed to obtain a viscous liquid material in which ITO particles were uniformly dispersed in the resin solution.

Then, a viscous liquid material was applied onto a PET film using an applicator and dried at 100 ° C. for 1 hour to form a transparent coating film having a thickness of 2 μm on the PET film.

Example 2 In the same manner as in Example 1, 60 parts of xylene, 20 parts of styrene, 19.95 parts of methyl acrylate, 0.05 part of acrylic acid and 0.6 part of azobisisobutyronitrile.
Part, nonvolatile content 40% by weight, resin weight average molecular weight 1000
A resin solution having an acid value of 00 and an acid value of 1.0 was obtained. Using this resin solution, kneading and coating were carried out in the same manner as in Example 1 to prepare a 2 μm thick transparent coating film on the PET film.

Example 3 In the same manner as in Example 1, 60 parts of xylene, 20 parts of styrene, 19.2 parts of methyl acrylate, 0.8 part of mono (2-methacryloyloxyethyl) acid phosphate and azobisisobutyronitrile. From 1.0 parts, non-volatile content 41% by weight, weight average molecular weight of the resin 50000,
A resin solution having an acid value of 5.6 was obtained. Using this resin solution, kneading and coating were carried out in the same manner as in Example 1 to prepare a 2 μm thick transparent coating film on the PET film.

Example 4 Non-volatile content 60% by weight, weight average molecular weight 65,000, acid value 7 polyester resin solution 30.0 parts, I
Kneading and coating were carried out in the same manner as in Example 1 using 80.0 parts of TO and 140.0 parts of a mixed solvent having a butanol / xylene weight ratio of 4/6 to prepare a transparent film having a thickness of 2 μm on a PET film. .

Comparative Example 1 In the same manner as in Example 1, from 60 parts of xylene, 20 parts of styrene, 19.5 parts of methyl acrylate, 0.5 part of acrylic acid and 3 parts of azobisisobutyronitrile, a nonvolatile content of 42 parts was obtained. A resin solution having a weight percentage of 5,000, a resin weight average molecular weight of 5,000 and an acid value of 9.7 was obtained. Using this resin solution, kneading and coating were carried out in the same manner as in Example 1 to prepare a 2 μm thick transparent coating film on the PET film.

Comparative Example 2 In the same manner as in Example 1, 60 parts of xylene, 20 parts of styrene, 19.95 parts of methyl acrylate, 0.01 part of acrylic acid and 0.6 of azobisisobutyronitrile.
Part, nonvolatile content 40% by weight, resin weight average molecular weight 1000
A resin solution having an acid value of 00 and an acid value of 0.2 was obtained. Using this resin solution, kneading and coating were carried out in the same manner as in Example 1 to prepare a 2 μm thick transparent coating film on the PET film.

Comparative Example 3 In the same manner as in Example 1, 60 parts of xylene, 20 parts of styrene, 19.2 parts of methyl acrylate, 0.8 part of mono (2-methacryloyloxyethylene) acid phosphate and azobisisobutyrate were used. From 0.3 parts of ronitrile, non-volatile content 40% by weight, weight average molecular weight of the resin 200,000,
A resin solution having an acid value of 5.6 was obtained. Using this resin solution, kneading and coating were carried out in the same manner as in Example 1 to prepare a 2 μm thick transparent coating film on the PET film.

(Comparative Example 4) A viscous liquid material was obtained in the same manner as in Example 4 except that a polyester resin solution having a nonvolatile content of 40% by weight, an average molecular weight of the resin of 49000 and an acid value of 0.3 was used. A transparent coating having a thickness of 2 μm was formed on the PET film.

Example 5 By the same method as in Example 1, 60 parts of xylene, 20 parts of styrene, 19.0 parts of methyl acrylate, methoxy polyethylene glycol methacrylate (molecular weight 4
96) 1.0 part and 2.0 parts of azobisisobutyronitrile, non-volatile content 41% by weight, resin weight average molecular weight 10000,
A resin solution having a polyalkylene glycol chain content of 2.0% by weight was obtained. Using this resin solution, kneading and coating were carried out in the same manner as in Example 1 to prepare a 2 μm thick transparent coating film on the PET film.

Example 6 In the same manner as in Example 1, from 60 parts of xylene, 20 parts of styrene, 19.0 parts of methyl acrylate, 1.0 part of methoxypolyethylene glycol methacrylate and 0.6 parts of azobisisobutyronitrile. , Nonvolatile content 40
A resin solution having a weight% of the resin, a weight average molecular weight of the resin of 100,000 and a polyalkylene glycol chain content of 2.0% by weight was obtained. Using this resin solution, kneading and coating were carried out in the same manner as in Example 1 to prepare a 2 μm thick transparent coating film on the PET film.

Example 7 In the same manner as in Example 1, from 60 parts of xylene, 20 parts of styrene, 5.0 parts of methyl acrylate, 15 parts of methoxypolyethylene glycol methacrylate and 0.6 part of azobisisobutyronitrile, a nonvolatile A resin solution having a content of 40% by weight, a weight average molecular weight of the resin of 100,000 and a polyalkylene glycol chain content of 30% by weight was obtained. Using this resin solution, kneading and coating are carried out in the same manner as in Example 1,
A 2 μm thick transparent coating was prepared on the PET film.

Comparative Example 5 In the same manner as in Example 1, from 60 parts of xylene, 20 parts of styrene, 19.0 parts of methyl acrylate, 1.0 part of methoxypolyethylene glycol methacrylate and 3 parts of azobisisobutyronitrile, non-volatile A resin solution having a content of 42% by weight, a resin weight average molecular weight of 5000, and a polyalkylene glycol chain content of 2.0% by weight was obtained. Using this resin solution, kneading and coating are carried out in the same manner as in Example 1,
A 2 μm thick transparent coating was prepared on the PET film.

Comparative Example 6 In the same manner as in Example 1, from 60 parts of xylene, 20 parts of styrene, 19.0 parts of methyl acrylate, 1.0 part of methoxypolyethylene glycol methacrylate and 0.3 part of azobisisobutyronitrile, a nonvolatile content was obtained. Min 40
A resin solution having a weight percentage of 200, a weight average molecular weight of the resin of 200,000 and a polyalkylene glycol chain content of 2.0 wt% was obtained. Using this resin solution, kneading and coating were carried out in the same manner as in Example 1 to prepare a 2 μm thick transparent coating film on the PET film.

Comparative Example 7 In the same manner as in Example 1, from 60 parts of xylene, 20 parts of styrene, 20 parts of methyl acrylate and 0.6 part of azobisisobutyronitrile, a nonvolatile content of 42% by weight was calculated. A resin solution having a weight average molecular weight of 100,000 was obtained. Using this resin solution, kneading and coating were carried out in the same manner as in Example 1 to prepare a 2 μm thick transparent coating film on the PET film.

(Comparative Example 8) In the same manner as in Example 1, from 60 parts of xylene, 10 parts of styrene, 10 parts of methyl acrylate, 20 parts of polyethylene glycol monomethacrylate and 0.6 part of azobisisobutyronitrile, a nonvolatile content was obtained. 40% by weight,
A resin solution having a resin weight average molecular weight of 100,000 and a polyalkylene glycol chain content of 50% by weight was obtained. Using this resin solution, kneading and coating were performed in the same manner as in Example 1, and PET was used.
A 2 μm thick transparent coating was prepared on the film.

Comparative Example 9 Kneading and coating were carried out in the same manner as in Example 5 except that the solvent was changed to xylene alone.
A 2 μm thick transparent coating was prepared on the T film.

(Comparative Example 10) Kneading and coating were conducted in the same manner as in Example 5 except that the solvent was changed to butanol alone.
A 2 μm thick transparent coating was prepared on the ET film.

Example 8 By the same method as in Example 1, 60 parts of xylene, 14.5 parts of styrene, 10.0 parts of methyl acrylate, 0.5 part of acrylic acid, 15 parts of methoxypolyethylene glycol methacrylate and azobisisobutyronitrile. 2.0
Part, nonvolatile content 44% by weight, resin weight average molecular weight 1000
A resin solution having an acid value of 0, an acid value of 9.7 and a polyalkylene glycol chain content of 30% by weight was obtained. Example 1 using this resin solution
Kneading and coating are performed in the same manner as above, and 2 on the PET film.
A transparent coating having a thickness of μm was prepared.

Example 9 By the same method as in Example 1, 60 parts of xylene, 14.95 parts of styrene, 10.0 parts of methyl acrylate,
Acrylic acid 0.05 parts, methoxy polyethylene glycol methacrylate 15 parts and azobisisobutyronitrile 0.
From 6 parts, nonvolatile content 40% by weight, resin weight average molecular weight 10
0000, acid value 1.0, polyalkylene glycol chain content 30
A wt% resin solution was obtained. Using this resin solution, kneading and coating were carried out in the same manner as in Example 1 to prepare a 2 μm thick transparent coating film on the PET film.

Example 10 In the same manner as in Example 1, 60 parts of xylene, 20 parts of styrene, 18.95 parts of methyl acrylate, 0.05 part of acrylic acid, 1.0 part of polyethylene glycol monomethacrylate and azobisisobutyronitrile. From 0.6 parts, nonvolatile content 40% by weight, resin weight average molecular weight 10000
0, acid value 1.0, polyalkylene glycol chain content 2.0
A wt% resin solution was obtained. Using this resin solution, kneading and coating were carried out in the same manner as in Example 1 to prepare a 2 μm thick transparent coating film on the PET film.

Example 11 30 parts of a polyester resin having a polyethylene glycol chain content of 5% by weight, a nonvolatile content of 60% by weight, a weight average molecular weight of 30,000 and an acid value of 5 in the resin,
80.0 parts ITO, butanol / xylene weight ratio 4 /
Kneading and coating were carried out in the same manner as in Example 1 using 140.0 parts of the mixed solvent of No. 6 to prepare a transparent coating film having a thickness of 2 μm on the PET film.

Comparative Example 11 By the same method as in Example 1, 60 parts of xylene, 14.5 parts of styrene, 10.0 parts of methyl acrylate, 0.5 part of acrylic acid, 15 parts of methoxypolyethylene glycol methacrylate and azobisisobutyronitrile. 3.0
Part, nonvolatile content 42% by weight, resin weight average molecular weight 500
A resin solution having 0, an acid value of 9.7 and a polyalkylene glycol chain content of 30% by weight was obtained. Example 1 using this resin solution
Kneading and coating are performed in the same manner as above, and 2 on the PET film.
A transparent coating having a thickness of μm was prepared.

Comparative Example 12 In the same manner as in Example 1, 60 parts of xylene, 14.99 parts of styrene, 10.0 parts of methyl acrylate,
0.01 parts acrylic acid, 15 parts methoxy polyethylene glycol methacrylate and azobisisobutyronitrile 0.
From 6 parts, non-volatile content 41% by weight, resin weight average molecular weight 10
0000, acid value 0.2, polyalkylene glycol chain content 30
A wt% resin solution was obtained. Using this resin solution, kneading and coating were carried out in the same manner as in Example 1 to prepare a 2 μm thick transparent coating film on the PET film.

Comparative Example 13 In the same manner as in Example 1, 60 parts of xylene, 10 parts of styrene, 9.5 parts of methyl acrylate, 0.5 part of acrylic acid, 20 parts of methoxypolyethylene glycol methacrylate and azobisisobutyronitrile. From 0.6 parts, nonvolatile content 41% by weight, resin weight average molecular weight 10000
A resin solution having 0, an acid value of 9.7 and a polyalkylene glycol chain content of 50% by weight was obtained. Example 1 using this resin solution
Kneading and coating are performed in the same manner as above, and 2 on the PET film.
A transparent coating having a thickness of μm was prepared.

Comparative Example 14 By the same method as in Example 1, 60 parts of xylene, 14.5 parts of styrene, 10 parts of methyl acrylate, 0.5 part of acrylic acid, 15 parts of methoxypolyethylene glycol methacrylate and azobisisobutyronitrile. From 0.3 parts, non-volatile content 41% by weight, resin weight average molecular weight 20000
A resin solution having 0, an acid value of 9.7 and a polyalkylene glycol chain content of 30% by weight was obtained. Example 1 using this resin solution
Kneading and coating are performed in the same manner as above, and 2 on the PET film.
A transparent coating having a thickness of μm was prepared.

(Comparative Example 15) A polyester resin having a polyethylene glycol chain content of 5% by weight, a nonvolatile content of 60% by weight, a weight average molecular weight of 40,000 and an acid value of 0.2.
Parts, 80.0 parts of ITO, and 140.0 parts of a mixed solvent having a butanol / xylene weight ratio of 4/6 are kneaded and applied in the same manner as in Example 1 to form a transparent film having a thickness of 2 μm on a PET film. did.

The total light transmittances of the transparent coatings obtained in each of the above Examples and Comparative Examples were measured by UBE of JASCO Corporation.
The ST 55 type spectrophotometer was used to measure haze from Suga Test Instruments Co., Ltd.
The surface resistance was measured with an SM color computer and with a Loresta AP MCP-T400 surface resistance measuring instrument manufactured by Mitsubishi Petrochemical Co., Ltd., respectively. Table 1 shows the test results. The viscous liquids in which the ITO powders obtained in Examples were dispersed were allowed to stand for 1 month at room temperature and then easily returned to the original dispersion state by stirring with a disper.

[0062]

[Table 1]

[0063]

According to the present invention, the resin used has a weight average molecular weight of 8000 to 150,000, an acid value of 0.5 to 15 mg KOH / g due to the acidic functional group of the resin, and / or the content of a polyalkylene glycol chain in the resin. When a transparent conductive film is prepared from a conductive film-forming composition using a resin having an amount in the range of 0.5 to 40% by weight, an ITO powder, and an organic mixed solvent of a polar solvent / nonpolar solvent, the surface resistance value is Of the order of 10 ² to 10 ⁴ Ω / □, a light transmittance of 80% or more and a haze of 6% or less, and a conductive film having low resistance and excellent transparency can be obtained. Particularly, when the acid value of the resin is 0.5 to 15 mgKOH / g and the content of the polyalkylene glycol chain is 0.5 to 40% by weight, the surface resistance value is on the order of 10 ² Ω / □, the light transmittance is Of 85% or more and haze of 3% or less further improve the characteristics. In addition, this composition had good stability over time during storage.

Therefore, the transparent conductive film formed by the composition of the present invention exhibits excellent effects in a wide range of fields such as transparent electrodes such as liquid crystals, window materials for solar cells, infrared reflective films and antistatic films. You can

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location // G02F 1/1343 (72) Inventor Akira Nishihara 1-297 Kitabukuro-cho, Omiya-shi, Saitama Mitsubishi Materials Corporation Central In the laboratory (72) Inventor Maoki Ishihara 134-163 Yamamotocho, Utsunomiya City, Tochigi Prefecture

Claims (4)

[Claims] 1. A resin solution comprising a resin having an acidic functional group and a mixed organic solvent of a polar solvent and a nonpolar solvent,
A composition for forming a conductive film in which an indium oxide powder containing tin is dispersed, wherein the acid value of the resin is 0.5 to 15 mgKOH /
g, a composition for forming a conductive film having a weight average molecular weight of 8,000 to 150,000. 2. A composition for forming a conductive film, wherein indium oxide powder containing tin is dispersed in a resin solution comprising a resin having a polyalkylene glycol chain and a mixed organic solvent of a polar solvent and a nonpolar solvent. A composition for forming a conductive film, wherein the resin has a polyalkylene glycol chain content of 0.5 to 40 wt% and a weight average molecular weight of 8000 to 150,000. 3. A conductive film in which tin-containing indium oxide powder is dispersed in a resin solution composed of a resin having both an acidic functional group and a polyalkylene glycol chain and a mixed organic solvent of a polar solvent and a non-polar solvent. A composition for forming, wherein the resin has an acid value of 0.5 to 15 mgKOH / g, a polyalkylene glycol chain content of 0.5 to 40% by weight, and a weight average molecular weight of 8000 to 150,000. Composition. 4. The indium oxide powder containing tin is ultrafine particles having an Sn content of 1 to 15 mol% with respect to In and an average primary particle diameter of 0.2 μm or less, and the nonvolatile content of the resin solution is 5 to 50% by weight, and the weight ratio of the polar solvent to the nonpolar solvent of the mixed organic solvent is in the range of 0.5 / 9.5 to 7/3, for forming a conductive film according to claim 1. Composition.