JPH01215874A - Coating material composition - Google Patents

Abstract

PURPOSE:To obtain a conductive coating material having improved storage stability and environmental resistance without reduction in its conductivity and electromagnetic wave shielding effect, by mixing a copper powder, a resin binder, a specified mixture of surface active agents, and a solvent together. CONSTITUTION:100pts.wt. phosphate surface active agent (a) comprising compounds of formula I and/or formula II (wherein R<1> is 8-22C alkyl or alkenyl; R<2> is OH or R<1>O; R<3> is a residue obtained by the addition reaction of 1mol. of a higher alcohol having R<1> or an alkylphenol having 1-12C alkyl with 1-100mol. of ethylene oxide and/or propylene oxide; and R<4> is OH or R<3>O) is mixed with 10-500pts.wt. surface active agent (b) based on an aminoether ester having at least one functional group of formula III (wherein R<5> is 7-21C alkyl or alkenyl; R<6> is ethylene or propylene; and n is 1-50) in the molecule to give a mixture. The title composition is obtained by mixing 30-95wt.% copper powder, 70-5wt.% resin binder, 0.05-10wt.% above- mentioned mixture, and a solvent.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an electromagnetic shielding abrasive, and more specifically,
The present invention relates to a copper-based conductive coating composition that improves the conductivity of a coating film.

[Prior art] Conductive paints, which are made by kneading conductive fillers such as nickel powder, silver powder, copper powder, and carbon powder into various resin binders, have been used as electromagnetic shielding materials to protect electronic devices from electromagnetic interference. This paint is sprayed onto the surface of a plastic molded product to shield it from electromagnetic waves. Among various conductive paints, copper-based conductive paints are cheaper than paints using silver powder or nickel powder, and have excellent shielding effects.

However, copper-based conductive paints have poor storage stability because the copper powder aggregates in the paint, making it difficult to obtain a good dispersion state. Furthermore, they are easily oxidized in environments such as heat and humidity, and therefore have poor environmental resistance. There is a problem in that it is likely to cause deterioration of properties and conductivity (attenuation of shielding effect). Various proposals have been made to solve this problem. For example, JP-A-5
Publication No. 6-16'3166, JP 56-167167
No. 1, JP-A-59-36170, JP-A-57-
34606, JP 6C16B239, JP 58-145769, JP 61-1639
It is described in JP-A No. 75, JP-A-60-202166, and JP-A-56-103260.

These conductive paints can improve storage stability and environmental resistance to some extent without reducing the conductivity and electromagnetic shielding effect of copper powder.

[Problems to be Solved by the Invention] However, conventional conductive coating compositions do not necessarily exhibit excellent storage stability and environmental resistance. Also,
The conductivity of the coating film is also not good.

This invention was made based on the above-mentioned background, and its purpose is to eliminate the above-mentioned drawbacks of the conventional conductive paint without reducing the conductivity and electromagnetic shielding effect of the conductive paint. Another object of the present invention is to provide a conductive paint that improves the storage stability and environmental resistance of the paint and imparts conductivity to the paint film.

[Means for Solving the Problems] As a result of conducting various tests and research on components to be added to conductive paints, the present inventor found that by adding a mixture of a phosphate ester surfactant and an aminoether ester, The present invention was found to be effective in achieving the object of the present invention, and the present invention was completed.

That is, the conductive coating composition of the present invention is characterized by comprising copper powder, a resin binder, a mixture of a phosphate ester surfactant and an aminoether ester surfactant, and a solvent.

In a preferred embodiment of the present invention, the phosphate ester surfactant is of the following general formula
Compounds represented by I can also be used.

(In the formula, R1 is an alkyl group or an alkenyl group having 8 to 22 carbon atoms, R is an OH group or an R10 group, and R3 is a higher alcohol having an alkyl group or an alkenyl group having 8 to 22 carbon atoms or a C 1 1 to 100 moles of ethylene oxide or/and propylene oxide are added to 1 mole of alkylphenol having ~12 alkyl groups, and R is an OH group or R''0.
In a preferred embodiment of the present invention, as the aminoether ester surfactant, one having at least one of the following functional groups in one molecule can be used.

RCo (OR6) N group (J, R5 has 7 to 2 carbon atoms) alkyl group, alkenyl group, R6 is ethylene group or propylene group, n is 1 to
50) In a preferred embodiment of the present invention, the mixing ratio of the phosphate ester surfactant and the aminoether ester surfactant is set to 100 parts by weight of the phosphate ester surfactant. Activator 10-500
It can be parts by weight.

In a preferred embodiment of the present invention, the amount of the mixture of the phosphate ester surfactant and the aminoether ester surfactant added is 0.0 with respect to the coating composition excluding the solvent.
The content may be 5 to 10% by weight.

This invention will be explained in more detail below.

Copper powder The shape of the copper powder used in this invention can be obtained by electrolytic method, reduction method,
There are dendritic, granular, and spherical shapes obtained by the atomization method.
Historically, there are flakes made by mechanically processing these using a whole mill.

Also, VJ4! ! Dendritic copper powder, flaky copper powder, granular copper powder, and spherical copper powder can be mixed and used using a mixer. By this mixing, the degree of contact with the copper powder can be increased, and the conductivity can be improved. Preferably, granular, spherical, or other shaped copper powder is mixed with the dendritic copper powder.

Among the copper powders used in this invention, the dendritic copper powder obtained by electrolytic method is 0. , 50-2. 00 g/crj apparent density, ], Orr? /g or less specific surface area, 10011
It is preferable to have a particle size distribution of m or more 1.'' and an average particle diameter of 5 to 30 μm.
[If it is less than i or exceeds 2.00 g/cRi, it will have a significant negative effect on coating workability, and the specific surface area], []0I
If T1'/g is exceeded, the oxidation resistance of the copper powder will be significantly inferior, and if the particle size distribution exceeds 100 μm, coating workability will deteriorate due to coarse particles, making it impossible to obtain a uniform coating film.The average particle size If the thickness is outside the range of 5 to 30 μm, a coating film exhibiting uniform conductivity will not be obtained, and the tip of the nostle will become clogged when the paint is sprayed.

In granular or spherical shapes obtained by reduction method or atomization method, 0
．． 50-2. OOg/c〃(tap density, 1,0rr
It is preferable to have the following specific surface area, particle size distribution of f/g, 011-50 μm, and average particle size of 3-15 μm.

Furthermore, as the raw material copper powder that can be used in this invention, metals such as silver, nickel, zinc, platinum, and palladium, alloys such as solder, metal organics such as organosilicon compounds, organotitanium compounds, and organoaluminum compounds are also available. The copper powder may be partially or entirely coated with compounds, surfactants, amino acids, amines, carbonic acids, and derivatives thereof.

Furthermore, an inorganic or organic treatment agent or lubricant used in the copper powder manufacturing process may be attached to the surface of the copper powder.

The raw copper powder is pretreated to remove oxidation from the surface of the copper powder using reagents such as inorganic acids, organic acids, and various reducing agents, as well as reducing gases such as ammonia gas and hydrogen gas. It is preferable to remove the coating. Additionally, the copper powder to be treated can be dried as a pretreatment.

Phosphate ester surfactant One of the components coated on the copper powder is a phosphate ester surfactant.

As the phosphate ester surfactant used in this invention, it is possible to use a compound represented by general formula I and/or II.

In the above formulas I and 2, R1 is an alkyl group or alkenyl group having 8 to 22 carbon atoms, R2 is an OH group or RO
The group R3 is a higher alcohol having an alkyl group or an alkenyl group having 8 to 22 carbon atoms or a carbon number 1 to 12
1 to 1 mole of ethylene oxide or/and propylene oxide to 1 mole of alkylphenol having an alkyl group of
is an OH group or an R''O group.

This phosphate ester surfactant is, for example, decyl alcohol, lauryl alcohol, tridecyl alcohol, myristyl alcohol, stearyl alcohol, cetyl alcohol, oleyl alcohol, a mixed alcohol having 11 to 15 carbon atoms from the oxo method, or a carbon number 12 ~13 secondary alcohols and their higher alcohols 1
mol of a nonionic surfactant to which 1 to 100 mol of ethylene oxide or/and propylene oxide is added by a known method, to 1 mol of an alkylphenol such as butylphenol, octylphenol, nonylphenol, dodecylphenol, dinonylphenol, Using a nonionic surfactant as a raw material to which 1 to 100 moles of ethylene oxide and/or propylene oxide have been added by a known method, phosphorus such as phosphorus oxychloride or phosphorus pentoxide is added to 1 mole of these raw materials. The compound, preferably phosphorus pentoxide, is prepared by a known method at 0.0%. 3-1
It is obtained by a 0 mol reaction, and is usually obtained as a reaction mixture of a monoester and a diester.

Among the above phosphate ester surfactants, preferred are lauryl alcohol, tridecyl 7' alcohol, oleyl alcohol, and oxo-based surfactants having 11 to 1 carbon atoms.
The raw material is a nonionic surfactant prepared by adding 5 to 15 moles of ethylene oxide or/and propylene oxide to 1 mole of the mixed alcohol, octylphenol, or nonylphenol of No. 5 by a known method.

The separation and purification of the synthesized phosphate ester surfactant is
This can be done using methods such as distillation, extraction, recrystallization, and column chromatography.

Aminoetherester surfactant Specifically, the aminoetherester surfactant used in the present invention has at least the following functional groups in one molecule.

In the above formula, R5 is an alkyl group or an alkyl group having 7 to 21 carbon atoms, R6 is an ethylene group or a propylene group, and [1 is 1 to 50].

Examples of such include triethanolamine, triisopropanolamine, and polyalkylene polyamines such as ethylenediamine, propylenediamine, triethylenetetramine, diethylenetriamine, tetraethylenepentamine, aminoethyleneaminopropylamine, decylamine, etc.)・Alkylamines such as decylamine, myristylamine, valmitylamine, oleylamine, cetylamine, stearylamine, alkyl polyalkylene polyamines such as dodecyl aminoethylamine, tallow aminopropylamine, dodecyl aminopropylamine, dodecyl diethylene triamine, tetradecyl diethylene triamine, lauryl Amino group 1 in fatty acid amide amines such as amide ethylamine, stearyl amide ethyl ethylenecyamine, alkylimidacillin derivatives such as N-laurylhydroxyethyl imidazoline, and N-oleylaminoethyl imidacillin.
After adding 1 to 50 moles of ethylene oxide or/and propylene oxide per unit by a known method, lauric acid, stearic acid, oleic acid, isostearic acid, palmitic acid, myristic acid, linoleic acid, etc. having 8 to 22 carbon atoms are added. can be obtained by reacting fatty acids such that each molecule has at least one RCo(OR6) N group by a known method.

Preferred in this invention are triethanolamine, ethylenediamine, triethylenete!・Oleic acid, isostearic acid, lauric acid monoester of 5-20 mole adduct of ethylene oxide with lamin: decylamine, dodecylamine, myristylamine, palmitylamine, oleylamine, cetylamine, stearylamine, tallow aminopropylamine, dodecyl It is preferable to use 5 to 20 moles of ethylene oxide (-J additives of oleic acid, isostearic acid, and lauric acid mono- or diesters) such as aminopropylamine.

The synthesized aminoether ester surfactant can be separated and purified by methods such as distillation, extraction, recrystallization, and column chromatography.

Resin Binder Resin binders that can be used in the present invention include thermoplastic resins and thermosetting resins that have better tightness than plastics commonly used in electronic devices. For example, in contrast to plastics such as ABS, polystyrene, PPO, polycarbonate I, etc.
Polyurethane resins, polyester resins, styrene resins, phenol resins, epoxy resins, etc. can be used.

The selection of the resin binder can be, for example, thermoplastic or Q
The distinction in rmability differs depending on the application; thermoplastic resins are generally used for electronic device casings or plastics, and thermosetting resins are generally used for electronic circuits or the back side. .

Direct type The solvent that can be used in this invention is preferably an organic solvent that dissolves the resin binder, dispersant, etc. and has low reactivity. For example, hydrocarbons such as toluene, hexane, and xylene; alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, and butyl alcohol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; and ethyl acetate and butyl acetate. or a mixture of two or more organic solvents such as esters of, methyl calpitol, ethyl calpitol, methyl cellosolve, and ethyl cellosolve are preferred.

In addition to the above components, various additives may be included depending on the purpose. Examples of such agents include reducing agents, surfactants, antisettling agents, antifoaming agents, thickeners, thixotropic agents, rust preventives, and flame retardants.

Conductive Coating Composition The coating composition of the present invention contains copper powder, a resin binder, a mixture of a phosphate ester surfactant and an aminoether ester surfactant, and a solvent.

The coating composition of this invention is produced by blending the above components simultaneously or sequentially in various orders. In this invention, the manufacturing method is arbitrary.

The mixture of the phosphate ester surfactant and the aminoether ester surfactant to be added can be obtained by mixing predetermined amounts of each of the phosphate ester surfactant and the aminoether ester surfactant. .

A mixture of a phosphate ester surfactant and an aminoether ester surfactant can be diluted with, for example, an organic solvent. Organic solvents that can be used here include preferably nonpolar solvents such as toluene and hexane, as well as polar solvents such as alcohol and acetone.

Hereinafter, the blending ratio or mixing ratio of this composition will be explained in detail.

The copper powder content in the coating composition excluding the solvent component is 30 to 9.
5% by weight binding, preferably 50-80! I! The amount is assumed to be 9δ. This means that if the content is less than 50% by weight, the conductivity of the coating film will begin to decline, if it is less than 30% by weight, this tendency will become significant, and if it exceeds 80% by weight, it will become difficult to form a coating. This is because when the content exceeds 95% by weight, this tendency becomes more pronounced.

In this invention, the mixing ratio of the phosphate ester surfactant and the aminoether ester surfactant detailed above is, for example, based on 100 parts by weight of the phosphate ester surfactant. Surfactant 10
~500 parts by weight, preferably in terms of properties, so that the acid value of the phosphate ester surfactant and the amine value activity of the aminoether ester surfactant are neutralized. . in particular,
The aminoether ester surfactant is used in an amount of 30 to 200 parts by weight per 100 parts by weight of the phosphate ester surfactant.

The amount of the mixture of phosphate ester surfactant and aminoether ester surfactant added in the coating composition excluding the solvent component is 0.01 to 15% by weight, preferably 0.0% by weight.
It is 5 to 10% by weight. If it is less than 0.05% by weight, the dispersibility of the copper powder will be lowered, and the conductivity of the coating film will also be lowered, and if it is less than 0.01% by weight, this tendency will be significant.
On the other hand, if it exceeds 110% by weight, an excessive mixture is formed on the surface of the copper powder, making it impossible to obtain good conductivity.
This is because the tendency becomes more pronounced when the value is exceeded.

The amount of the resin binder added in the coating composition excluding the solvent component is 70 to 5% by weight, preferably 50 to 20% by weight. If it is less than 50% by weight, the conductivity of the coating film will be low, and if it is less than 5% by weight, this tendency will be noticeable.On the other hand, if it is more than 50% by weight, excessive binder will be formed on the surface of the copper powder. 70% by weight, making it impossible to obtain good conductivity due to
This is because the tendency becomes more pronounced when the value is exceeded.

Although limited to copper powder in the above specification, the mixture of phosphate ester surfactant and aminoether ester surfactant in this invention can be used as a surface treatment agent for metal powder in boat fishing. It can also be used as an additive to improve the dispersibility of metal powder in inorganic or organic solvents.

[Function] In this invention and preferred embodiments having the above configuration,
It works as follows.

In this invention, a mixture of a phosphate ester surfactant and an aminoether ester surfactant is added to the dispersion of this conductive coating composition, and the surface of the copper powder is coated with the mixture, and the surface of the copper powder is coated with the mixture. Modify. Specifically, phosphate ester surfactants and aminoether ester surfactants have a hydrophilic part and a lipophilic part, so the hydrophilic part reacts with adsorbed water on the copper powder surface or coating. on the other hand, the lipophilic parts are oriented on the outside of the copper powder. The film of this lipophilic part acts as a hydrophobic film on the surface of the copper powder, and furthermore, this lipophilic part acts as a hydrophobic film on the surface of the copper powder.Furthermore, in the conductive composition, this lipophilic part interacts with resin binder molecules through van der Waals forces, hydrogen bonds, ionic bonds, and covalent bonds. By skillfully intertwining with each other, the copper powder forms a good dispersion state in paints and coatings by stirring, shear stress during the kneading process, etc.

[Effects of the Invention] The conductive coating composition according to claim 1, which has the following effects according to the present invention, contains a mixture of a phosphate ester surfactant and an aminoether ester surfactant. It is possible to form a strong film that does not impair conductivity by reacting with adsorbed water on the copper powder surface or coating. Therefore, in the copper powder itself,
Good rust prevention, dispersibility, electrical conductivity, environmental resistance and storage stability of the coating material are improved, and the chemical and physical strength of the coating film is improved.

In the coating composition according to claim 4, the mixing ratio of the phosphoric acid ester surfactant and the aminoether ester surfactant is specified, and within this range, it is particularly preferable in terms of characteristics:
This is because the acid value of the phosphate ester surfactant and the amine value equivalent of the aminoether ester surfactant are blended so that they are neutralized, so it does not oxidize the copper powder and is favorable in terms of characteristics. be.

In addition, in the coating composition described in Item 1, Shimizu Item 5, the amount of the mixture of the phosphate ester surfactant and aminoether ester surfactant in the coating composition excluding the solvent component is 0.05 to 10. % by weight, it is possible to maintain the conductivity of the coating film.

[Example] The invention will be illustrated by the following example.

The phosphate ester surfactant used in this example was prepared by reacting the following number of moles of phosphorus pentoxide with 1 mole of the starting materials shown in Table 1. It was prepared by

Table 1 1-1 Nok 7 Enol 8 E OO,41-
2 lauryl alcohol 0.51-3 lauryl alcohol: I-ru 3E0 0.41-4 oleyl alcohol 5E0 0.41-5
To IJ Desiral: l-Lua Eo 0J1-6
Octylphenol 2POυ, 51-7 Nonylphenol 0 0.41-8 Doha/-
Lua Afj-
/1z6PO2E0 0.4 Note) EO ethylene oxide, Po/propylene oxide b, aminoether ester surfactant The starting materials shown in Table 2 and fatty acids were mixed and reacted to produce the aminoether ester used in this example. Surfactants 2-1 to 2-9 were prepared.

Table 2 No. Starting material EO/PO ((I added mol fatty acid mol number 2-1 ethylenediamine
20EO oleic acid 1.52-2 Propylenecyamine 6EO Lauric acid 2.02
-3 1-liethanolamine - Oleic acid 1゜02-4 Cetylamine
15EO Isostearic acid 1.02-5 Laurylamine 10EO Stearic acid 1,22
-7 1-Lyethylenethe I/lamin 8PO coconut fatty acid 2.52-8 Oleinamine 4
PO/l0EO myristic acid 1. OC, a mixture of a phosphate ester surfactant and an aminoether ester surfactant (the present invention) The phosphate ester surfactant in Table 1 and the aminoether ester surfactant in Table 2 are combined in Table 1. Mixtures 3-1 to 18 according to the present invention were prepared using the combinations and compositions shown in Table 3.

Table 3 3-1 1-1 100g 2-1 7.0g3-
2 1. -2 100g 2-2 30g3-3
1. -3 100g 2-3 60g3-4 1-
4 100g 2-4 30g3-5 1-5 1
00g 2-5 40g3-6 1-6 100g
2-6 80gB-71-7100g 2-
7 120 g3-8 1-8100g 2-8
40g3-9 1-9 100g 2-9 50g
B-101-5100g 2-2 90g3-II
1-5 100g 2-7 180 g3-1
2 1-6 100g 2-3 60g3-13
1-6 100g 2-5 40g3-14 1-
7 100g 2-2 80g3-15 1-7
100g 2-8 3ag3-1fi 1-8
100g 2-2 120 g3-17 1-8
100g 2-4 35g3-18 1-8 10
0g 2-5 50gd, Comparative Surfactants For comparison, the surfactants in Table 4 below were used.

Table 4 Comparison sample no.

4-1... Phosphate ester surfactant (No. 1
-1) Triethanolamine salt 4-2... Phosphate ester surfactant (No. 1)
-1) Na salt 4-3... Aminoether ester surfactant (
No, 2-1) 'It Germany 4-4... Phosphate ester surfactant (NO, 1
-5) Monoethanolamine salt 4-5 Phosphate ester surfactant (No, 1-7
) Potassium salt 4-6... Aminoether ester surfactant (N
o, 2-8) Single e, copper powder A dendritic electrolytic copper powder (MF-D2, manufactured by Ii Metal Mining Co., Ltd.) shown in Table 5 was used.

Table 5 Apparent Density 0.8-1. 1g/am3 Specific surface area 0.40i/g Purity 99.2% or more HNO3 insoluble matter Less than 0.03% Reduction loss Less than 0.80% Average particle size 8.0μ[n Experimental example 1 Volume resistivity of coating film (Conductivity) Copper powder in Table 5, acrylic resin solution for copper powder (solid content 50% by weight)
), the mixture shown in Table 3, and a solvent (toluene) were stirred for 10 minutes in a homomixer to prepare a conductive paint. A circuit was formed on an acrylic plate using the obtained conductive paint using a screen printing machine, and after drying in the atmosphere at 40° C. for 30 minutes, the volume resistivity of this circuit was measured.

As a result, the copper powder content excluding the solvent component was 50 to 80% by weight.
, mixture content of phosphate ester surfactant and aminoether ester surfactant 0.05 to 10% by weight
The circuits obtained from the conductive paint according to the invention in 1999 had a volume resistivity of about 8X], 0' to XIO'' Ω·cm.

Comparative Experiment Example 2 Volume resistivity (conductivity) of coating film Copper powder in Table 5, acrylic resin solution (solid content 50% by weight) for copper powder, comparative sample in Table 4, and solvent (toluene) A conductive paint was prepared by stirring with a homomixer for 10 minutes. The obtained conductive paint was used to form a circuit on an acrylic board using a screen printing machine, and then printed at 40°C at 30°C.
After drying for minutes, the volume resistivity was measured on the circuit.

As a result, the copper powder content excluding the solvent component was 50 to 80% by weight.
6. The circuit obtained from this comparative conductive paint at a comparative sample content of 0.05-10% by weight is about 5 x 10
It had a volume resistivity of ~lXl0-2 Ω·cm.

From the results of Experimental Example] and 2, it can be concluded that the conductive paint of the present invention has excellent dispersibility and good conductivity.

Experimental Example 3 Aging resistance of paint The coating composition prepared in Experimental Example 1 was heated at 25°C for 3 months.
After being left in an environment of 70% RH, a circuit was formed in the same manner, and the volume resistivity of the circuit was measured.

As a result, the copper powder content excluding the solvent component was 50 to 80% by weight.
, mixture content of phosphate ester surfactant and aminoether ester surfactant 0.05 to 10% by weight
The circuits obtained from the conductive paint according to the invention in had a volume resistivity of 5×10′ to 8×]O′Ω·em.

Further, the dispersion state of the copper powder in the paint after standing was good.

Comparative Experimental Example 4 Paint Aging Resistance The coating composition prepared in Comparative Experimental Example 2 was heated for 3 months, 2
After being left in an environment of 5° C. and 170% RH, a circuit was formed using the same procedure, and the volume resistivity of the circuit was measured.

As a result, the copper powder content excluding the solvent component was 50 to 80% by weight.
The circuits obtained from this comparative conductive paint at a comparative sample content of 0.05 to 10% by weight had a volume resistivity of about 2 x 10 to 7 x 10'' cm.

From the results of Experimental Examples 3 and 4, it was found that the conductive paint of the present invention has excellent aging resistance and good dispersibility over a long period of time.

Experimental Example 5 Dispersibility of copper powder in coating composition Experimental Example 1 described above
The state of dispersion of copper powder was observed in the coating film applied to the acrylic plate.

An electron micrograph of a cross section of the coating film according to the present invention is shown in FIG. This photo shows the good dispersion of the copper powder in the resin binder and the strong adhesion between the acrylic base material and the resin binder.

An electron micrograph of a cross section of a comparative coating film is shown in FIG. This photo shows the poor dispersion state of copper powder in the resin binder.
Poor adhesion between the base material and the resin binder due to unevenness of the copper powder was observed.

[Brief explanation of the drawing]

Figure 1 is a 700x scan showing the structure of copper powder particles in a cross-section of a coating film of a paint according to the present invention, taken with an Ichiko microscope, and Figure 2 is a cross-section of a coating film of a comparative paint. There is a 7L scanning electron micrograph-C at 700x magnification showing the +j11 structure of copper powder particles.

Claims (1)

[Scope of Claims] 1. A coating composition comprising copper powder, a resin binder, a mixture of a phosphate ester surfactant and an aminoether ester surfactant, and a solvent. 2. The coating composition according to claim 1, wherein the phosphate ester surfactant comprises a compound represented by the following general formula I and/or II. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...I ▲There are mathematical formulas, chemical formulas, tables, etc.▼...II (In the formula, R^1 is an alkyl group or alkenyl group with 8 to 22 carbon atoms, R ^2 is an OH group or R^1O group, R
^3 is 1 to 1 mol of ethylene oxide or/and propylene oxide to 1 mole of a higher alcohol having an alkyl group or alkenyl group having 8 to 22 carbon atoms or an alkylphenol having an alkyl group having 1 to 12 carbon atoms.
The residue obtained by adding 100 moles, R^4, is an OH group or R^3O group) 3. The aminoether ester surfactant has at least one of the following functional groups in one molecule, The coating composition according to claim 1 or 2. R^5CO(OR^6)_nN group (wherein R^5 is an alkyl group having 7 to 21 carbon atoms or an alkelni group, R^6 is an ethylene group or a propylene group, and n is 1 to 50) 4. A claim in which the mixing ratio of the phosphate ester surfactant and the aminoether ester surfactant is 10 to 500 parts by weight of the aminoether ester surfactant per 100 parts by weight of the phosphate ester surfactant. The coating composition according to 1, 2 or 3. 5. The amount of the mixture of the phosphate ester surfactant and the aminoether ester surfactant added is 0.05 to 10% by weight based on the coating composition excluding the solvent. The coating composition according to any one of the items.