JPH0218469A - Copper powder for electrically conductive coating and electrically conductive coating composition - Google Patents

Abstract

PURPOSE:To obtain the title copper powder coated with an organic zirconate compound and hydroxyalkylamine, having rust proofing properties and capable of improving conductivity and environmental resistance by adding to a coating. CONSTITUTION:The aimed copper powder coated with a zirconate compound [preferably compound expressed by formula I (RO is readily hydrolyzable organic group; OR' is organic group exhibiting slightly hydrolyzable properties and oleophilic properties; X is 1-3)] and hydroxyalkylamine [preferably compound expressed by formula II (R<1> is hydroxyalkyl having at least one hydroxyl group; R<2> is alkyl or H; n is 1<=n<=3)]. Furthermore, a higher carboxylic acid ester consisting of higher fatty acid acrylate group and readily hydrolyzable alkoxy group is preferably used together with the organic zirconium compound. The copper powder is blended with a resin binder and solvent to provide the electrically conductive coating composition.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to electromagnetic shielding materials, and more specifically,
The present invention relates to copper powder coated with a metal organic compound as a dispersant and an organic amine as a rust preventive agent, and a conductive coating composition for shielding electromagnetic waves containing these metal organic compounds and the organic amine.

[Conventional technology]

As one of the electromagnetic wave shielding materials that protect electronic devices from electromagnetic interference, there are conductive paints that are made by kneading conductive fillers such as nickel powder, silver powder, copper powder, and carbon powder into various resin binders. Apply this to the surface of plastic molded products with a spray brush to shield electromagnetic waves. Among various conductive paints, copper-based conductive paints are
It is cheaper than paints using silver powder or nickel powder, and has excellent shielding properties.

However, copper-based conductive paints have problems in that the copper powder aggregates in the paint, making it difficult to obtain a good dispersion state, and moreover, it is easily oxidized in environments such as heat and humidity. Various proposals have been made in the past to solve this problem. For example, treating electrolytic copper powder with an organic carboxylic acid (Japanese Unexamined Patent Publication No. 60-258273), surface treatment of copper powder with a coupling agent (Japanese Unexamined Patent Publication No. 60-30200), copper powder Coating with silver (Japanese Patent Application Laid-Open No. 60-24327
7 specification), coating copper powder with organic titanate (
JP-A-59-174661 and JP-A-56-
36553 specification), coating copper powder with organic aluminum (Japanese Patent Application Laid-Open No. 59-179671), plating copper powder with solder (Japanese Patent Application Laid-Open No. 57-113505), Coating with copper oxide (JP-A-60-
35405 specification), etc. have been proposed.

[Problem to be solved by the invention]

A certain degree of effect can be obtained by subjecting copper powder to the above-described treatment.

However, the rust prevention properties of copper powder are not good, and the conductivity and environmental resistance of conductive paints are not sufficient.

In particular, the electromagnetic shielding performance deteriorated significantly.

This invention was made based on the above-mentioned background, and its purpose is to eliminate the drawbacks of the conventional copper powder for conductive paint and conductive paint without reducing the electromagnetic shielding effect. An object of the present invention is to provide a copper powder for use in a conductive paint and a conductive paint composition that have improved conductivity and environmental resistance of the copper powder itself and the paint.

[Means to solve the problem]

As a result of conducting various tests and research on copper powder and copper-based conductive paint, the present inventor selected an organic zirconate compound and an organic amine, and used the organic zirconate compound as a dispersant and the organic amine as a rust preventive agent. The present invention was completed based on the knowledge that this method shows excellent effects.

That is, the copper powder for conductive paint of the present invention is coated with an organic zirconate compound and a hydroxyalkylamine.

In a preferred embodiment of this invention, the hydroxyalkylamine is represented by the following structural formula.

(R') N (R2) n 3-n (wherein, R1 represents a hydroxyalkyl group having at least one hydroxyl group, R2 represents an alkyl group or hydrogen, and n represents an integer of 1≦n≦3. In a preferred first embodiment of the organic zirconate compound in this invention,
It is represented by the following general formula.

(RO)　　　Z　r　　(OR’)　4-.

(In the formula, RO is an easily hydrolyzable organic group, OR' is an organic group that is difficult to hydrolyze and exhibits lipophilicity, and X is 1 to 3
A second preferred embodiment of the organic zirconate compound in the present invention is a zirconium acylate polymer used together with a higher carboxylic acid ester.

One embodiment of the conductive coating composition of the present invention contains copper powder coated with a hydroxyalkylamine and an organic zirconate compound, a resin binder, and a solvent.

In another embodiment of the conductive coating composition according to the present invention, the hydroxyalkylamine and the organic zirconate compound are
Added to a mixed system of copper powder, resin binder, and solvent.

This invention will be explained in 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, and there are also flakes obtained by mechanically processing these.

Examples of copper powder used in this invention have an apparent density of 0.5 to 3.
．． 5g/ri, tap density 1.0-5.0g/cm,
1. with BET method. It has a specific surface area of less than 5 rrr/g, an average particle diameter of 3 to 20 μm as measured by a light transmission method, and a particle size distribution of 50 μm or less as measured by a light transmission method.

The shielding effect can be improved by processing granular or spherical copper powder into flake powder using a ball mill or the like. Also, V
A good shielding effect can be obtained by mixing dendritic copper powder and granular or spherical copper powder using a mold mixer or the like.

As the raw material copper powder that can be used in this invention, metals such as silver, nickel, zinc, platinum, palladium,
It may be coated in advance with an alloy such as solder, an organometallic compound such as an organosilicon compound, an organotitanium compound or an organoaluminium compound, a surfactant, an amino acid, a carboxylic acid, a derivative thereof, or the like. A preferable raw material coated copper powder is a copper powder in which all or part of the surface of the copper powder is coated with silver.

In addition to the above-mentioned materials, copper powder may be coated with components used in the production of conductive paint in advance.

In addition, as a pretreatment, the oxide film on the surface of the copper powder can be removed using reagents such as inorganic acids, organic acids, various reducing agents, or ammonia gas.
It can be removed by reducing gas such as hydrogen gas.

Hydroxyalkylamine The hydroxyalkylamine used in this invention is specifically represented by the following structural formula.

(In the formula, R1 represents a hydroxyalkyl group having at least one hydroxyl group having 1 to 5 carbon atoms, preferably 2 to 3 carbon atoms, and R2 represents an alkyl group having 1 to 5 carbon atoms, preferably 2 to 3 carbon atoms, or hydrogen (where n represents an integer of 1≦n≦3) Examples of such compounds include monoethanolamine, N
, N-dimethylethanolamine, N.

N-diethylethanolamine, jetanolamine,
Examples include N-butyljetanolamine, triethanolamine, triisopropanolamine, and monoisopropanolamine.

In this invention, the hydroxyalkylamine is reacted in advance in an aqueous solution on the surface of the copper powder from which the oxide film has been removed to form a film, and is also added directly to the mixed system of the copper powder and the resin binder.

The hydroxyalkylamine content in the conductive coating composition is 0.005 to 15% by weight, preferably 0.01 to 10% by weight, based on the weight of the copper powder.

This is because if it is less than 0.01% by weight, the oxidation resistance of the copper powder decreases, and if it is less than 0.005% by weight, this tendency is remarkable, and on the other hand, if it exceeds 10% by weight, the conductivity of the conductive coating composition decreases. This is because when the amount exceeds 15% by weight, this tendency becomes remarkable.

Organic Zirconate Compounds Certain zirconium compounds are used in this invention.

Examples of the organic zirconate compound include an organic zirconate compound represented by the following formula and a zirconium acylate polymer (described later).

(RO) Z r -(OR') 4-x (wherein, RO is an easily hydrolyzable organic group, OR' is an organic group that is hardly hydrolyzable and exhibits lipophilicity, and X is an organic group of 1 to 3 (integer) The organic zirconate compound represented by the above formula has both an organic group that is easily hydrolyzed and an organic group that is difficult to be hydrolyzed and exhibits lipophilicity.

Specific such compounds include, for example, isopropyltriisostearoylzirconate, isopropyltridodecylbenzenesulfonylzirconate, isopropyltris(dioctylpyrophosphate)zirconate, tetraisobutyropyrubis(dioctylphosphate)zirconate, tetraoctylbis(ditridecyl). phosphite) zirconate, tetra(2,2-diallyloxymethyl-1-butyl)bis(di-tridecyl)phosphite zirconate, bis(dioctylpyrophosphate)oxyacetate zirconate, bis(dioctylpyrophosphate)ethylene zirconate , isopropyltrioctanoylzirconate, isopropyldimethacrylisostearoylzirconate, isopropylisostearoyldiacrylzirconate, isopropyltri(dioctylphosphate)zirconate, isopropyltricumylphenylzirconate, isopropyltri(N-aminoethyl-aminoethyl) Zirconate, dicumylphenyloxyacetate zirconate, diisostearoyl ethylene zirconate, n-
Examples include butyltriisostearoylzirconate, isobutyltriisostearoylzirconate, tert-butyltriisostearoylzirconate, isopropyltrioleylzirconate, isobutyltrioleylzirconate, isobutyl(diisostearoyl)oleylzirconate, and the like.

In this invention, the amount of the organic zirconate compound used is 0.01 to 15% by weight, preferably 0.01 to 15% by weight based on the copper powder.
．． 05 to 10% by weight. If the amount used is less than the lower limit, oxidation resistance is poor, and patina and discoloration are likely to occur, as well as agglomeration of copper powder. This is because if the upper limit is exceeded, an excessive hydrophobic film is formed on the surface of the copper powder, which impairs conductivity.

Zirconium Acylate Polymer One embodiment of the organic zirconate compound used in this invention is a zirconium acylate polymer.

This zirconium acylate polymer is specified as follows. That is, a zirconium acylate polymer has an easily hydrolyzable alkoxy group bonded to a zirconium atom in the main chain (-Zr-0) and a hardly hydrolyzable and lipophilic acylate group also bonded to a zirconium atom. It is.

This zirconium acylate polymer has tetraalkoxyzirconium Z r (OR) 4 with carboxylic acid,
It can be obtained by reacting with acid anhydride, inorganic acid, etc., or by reacting tetrachlorozirconium Z r (CI) 4 with ammonia/carboxylic acid, carboxylic acid sodium salt, etc.

A preferred method for synthesizing a zirconium acylate polymer is a method in which tetraalkoxyzirconium Zr (OR)a is reacted with several times the molar amount of a carboxylic acid, particularly a higher fatty acid.

The method for preparing tetraalkoxyzirconium Z r (OR) 4 from several times the molar amount of carboxylic acid or isomers thereof includes, for example, tetraisopropylzirconium,
1 mol or more, preferably 3 to 6 mol, of stearic acid, palmitic acid, mystyric acid, lauric acid, capric acid, etc. per 1 mol of tetra-t-butylzirconium, tetra-n-butylzirconium, tetraisobutylzirconium, etc. , higher saturated fatty acids and their isomers, and higher unsaturated fatty acids such as oleic acid, linoleic acid, and liluic acid and their isomers.

Separation and purification of the synthesized zirconium acylate polymer can be performed using techniques such as dropletless extraction, extraction, recrystallization, and column chromatography.

Higher carboxylic acid ester In this invention, the higher carboxylic acid ester used together with the zirconium acylate polymer has a long chain of many carbons, and preferable esters include higher fatty acid acylate groups and easily hydrolyzable alkoxy There is something that consists of the base.

The portion of this ester that corresponds to a higher carboxylic acid is a higher fatty acid acylate group having 8 to 24 carbon atoms, and the portion of this ester that corresponds to an alcohol has 1 to 15 carbon atoms,
Preferably it is an alkoxy group having 1 to 10 carbon atoms.

Specific examples of such higher carboxylic acid esters include higher saturated fatty acids such as stearate, valmitate, mystilate, laurate, and caprate, and their isomers, oleate, and linoleate. , higher unsaturated fatty acids such as linoleic acid esters, and their isomers. This is because if the carboxylic acid ester used is of a lower grade, the hydrophobicity of the carboxylic acid ester film formed on the surface of the copper powder will be impaired, and the good dispersion state of the copper powder will not be achieved when forming paints and coatings with the resin binder. Because you can't get it.

Higher carboxylic acid esters that can be used in the present invention can be obtained by reacting alcohol with higher carboxylic acids during boat fishing, or esters that are by-produced when synthesizing zirconium acylate polymers can be used. .

When a mixture of a zirconium acylate polymer and a higher carboxylic acid ester is obtained from a reaction mixture of tetraalkoxyzirconium and a higher carboxylic acid, 1 mole of tetraalkoxyzirconium and 2 to 8 moles of higher carboxylic acid, preferably 1 mole of tetraalkoxyzirconium. and higher carboxylic acid in a ratio of 3 to 6 moles. If the amount is less than this range, mere acylates, such as monoacylates and zirconium alkoxy polymers will be produced, and no zirconium acylate polymer will be produced; if the amount is more than this range, zirconium acylate polymers will be quantitatively obtained, but only as by-products. This is because certain carboxylic acid esters and alcohols increase excessively. The alkoxy group of the tetraalkoxyzirconium used here has 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms. This is because when the number of carbon atoms exceeds 10, the hydrolysis reaction with water adsorbed on the surface of the copper powder does not proceed rapidly, and when the number of carbon atoms exceeds 15, the reactivity of acylate formation with carboxylic acid decreases. This is because the reaction will be significantly reduced and the reaction will hardly proceed.

Method for producing copper powder for conductive paints The method for producing coated copper powder according to the present invention involves adding an organic zirconate compound or hydroxyalkylamine dissolved in a solvent to copper powder (copper powder dispersion bath), and then removing the solvent. There are methods such as adding necessary amounts of organic zirconate compound and hydroxyalkylamine to copper powder (copper powder dispersion bath) and mixing and stirring. When using a dispersion bath of copper powder, the method includes removing the dispersion medium as necessary to obtain copper powder for conductive paint.

The copper powder dispersion bath used in this manufacturing method is one in which the copper powder to be coated is well dispersed in a dispersion medium, and examples of the dispersion medium used here include organic solvents such as water and alcohol. There is. As a preferred dispersion medium,
water, methyl alcohol, ethyl alcohol, toluene,
Examples include hexane and xylene. The amount of the dispersion medium is the amount necessary to form a good dispersion state of the copper powder, and is preferably set to the minimum amount possible.

The mixture of zirconium acylate polymer and higher carboxylic acid ester to be added can be obtained by mixing predetermined amounts of each of the zirconium acylate polymer and higher carboxylic acid ester, and the mixture of tetraalkoxyzirconium and higher carboxylic acid ester as described above. It can be obtained from a reaction mixture with an acid.

The mixing ratio of the zirconium acylate polymer and the higher carboxylic acid ester in this mixture is 95 to 5% by weight of the higher carboxylic acid ester to 5 to 95% by weight of the zirconium acylate polymer, preferably 10 to 90% by weight of the zirconium acylate polymer. % of the higher carboxylic acid ester, more preferably 80 to 20 weight % of the higher carboxylic acid ester to 20 to 80 weight % of the zirconium acylate polymer. This is because if the zirconium acylate polymer is below the lower limit of this range, the hydrophobicity will be markedly poor, and if the zirconium acylate polymer is above the upper limit of this range, the electrical conductivity will gradually decrease. Furthermore, if the higher carboxylic acid ester is below the lower limit of this range, the dispersibility of copper powder in forming paints and coatings will be significantly poor.

The hydroxyalkylamine and organic zirconate compounds can each be diluted with a suitable solvent.

For example, when diluting the organic zirconate compound with an organic solvent, the organic solvents that can be used include preferably non-polar solvents such as toluene and hexane, as well as polar solvents such as alcohol and acetone.

The amount of hydroxyalkylamine treated with copper powder is 0.
．． 0.005 to 15% by weight, preferably 0.01 to 10% by weight.

The amount of organic zirconate compound coated on the copper powder is 0.
0.05-15% by weight, preferably 0.01-10% by weight
It is. If it is less than 0.01% by weight, the dispersibility of the copper powder decreases, and the electrical conductivity and environmental resistance of the paint, as well as the chemical and physical strength of the coating film, begin to decrease, and if it is less than 0.005% by weight, the The trend becomes noticeable. On the other hand, when it exceeds 10% by weight, an excessive coating film is formed on the surface of the copper powder, and the electrical conductivity, environmental resistance, and chemical and physical strength of the coating film begin to decrease, and when it exceeds 15% by weight, this tendency tends to decrease. It becomes noticeable.

The organic zirconate compound and/or hydroxyalkylamine may be added to the copper powder dispersion bath, for example, by directly adding them in small amounts to the dispersion bath, or by diluting them with an organic solvent or the like. It is desirable that operational parameters such as addition rate and post-addition stirring time be appropriately selected depending on the surface condition of the copper powder, that is, the amount of adsorbed water, specific surface area, shape, etc.

After forming the organic zirconate compound or/and hydroxyalkylamine film, the dispersion medium is removed, if necessary. This is because, in some cases, if drying is insufficient, oxidation of the copper powder may occur, making it impossible to obtain good conductivity or shielding effects, and there is a risk that discoloration or patina may occur.

Conductive Coating Composition The conductive coating composition of the first aspect of the present invention contains copper powder coated with a hydroxyalkylamine and organic zirconate compound according to the present invention, a resin binder, and a solvent.

In another aspect, the conductive coating composition of the present invention is
An organic zirconate compound and a hydroxyalkylamine are added to a mixed system of copper powder, a resin binder, a solvent, and the like.

The resin binder that can be used in the present invention is one that has good adhesion to plastics that are commonly used in electronic devices. For example, ABS,
Acrylic resins, polyurethane resins, polyester resins, styrene resins, phenolic resins, epoxy resins, and the like can be used for electronic device housing plastics such as polystyrene, PPO, and polycarbonate.

In addition, solvents that can be used in this invention include toluene, thinner, hexane, methyl ethyl ketone, xylene, methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, methyl isobutyl ketone, and acetic acid to dissolve additives such as resin binders. One or a mixture of 211 or more organic solvents such as ethyl, butyl acetate, methyl calpitol, ethyl calpitol, methyl cellosolve, and ethyl cellosolve are preferred.

It is desirable that these selections be made in consideration of workability and the like.

The copper powder blended into this composition is 35 to 95% by weight, preferably 40% by weight, based on the solid content of the conductive composition.
~90% by weight.

Moreover, the resin binder blended into this composition is 5 to 70% by weight, preferably 10 to 60% by weight, based on the solid content of the conductive composition.

In addition to the above components, various additives can be included depending on the purpose. Such agents include reducing agents, surfactants, antisettling agents, antifoaming agents, thickening agents, thixotropic agents, rust preventives, and flame retardants.

The amount of hydroxyalkylamine added to copper powder is 0.
．． 0.005 to 15% by weight, preferably 0.01 to 10% by weight. If this is less than 0.01% by weight, the surface modification of the copper powder will be insufficient, and the conductivity and environmental resistance of the paint will begin to deteriorate. This is because if it is less than 0.005% by weight, this tendency becomes remarkable.On the other hand, if it exceeds 10% by weight, it will be excessive on the surface of the copper powder, hindering modification, and the conductivity and environmental resistance of the paint will begin to deteriorate. This is because when the amount exceeds %, the tendency becomes remarkable.

[For production]

In this invention having the above-described configuration, the nitrogen atom portion of the hydroxyalkylamine of the organic amine reacts with the surface of the copper powder to form a dense chelate film, thereby imparting rust prevention properties to the copper powder.

On the other hand, organic zirconate compounds have a hydrophilic organic group centered on the zirconium atom that is easily hydrolyzed and a lipophilic organic group that is difficult to hydrolyze. A substitution reaction occurs with the hydroxyl groups of the chelate film and adsorbed water on the surface of the copper powder. Therefore, the lipophilic organic groups are arranged on the outside of the copper powder surface, forming a hydrophobic film of the organic zirconate compound.

In an embodiment in which a mixture of a zirconium acylate polymer and a higher carboxylic acid ester is used, the zirconium acylate polymer has an easily hydrolyzable alkoxy group and a hardly hydrolyzable and lipophilic acylate group. reacts with the adsorbed water on the amine chelate film or coating, while the lipophilic acylate group portions are oriented to the outside of the copper powder. This lipophilic acylate group film acts as a hydrophobic film with the copper powder, and furthermore, this lipophilic acylate group part acts as a hydrophobic film with the resin binder molecules due to van der Waals forces, hydrogen bonds, etc. in the conductive composition. Copper powder is skillfully intertwined with ionic bonds, covalent bonds, etc., and forms a good dispersion state of copper powder in paints and coatings by stirring, shear stress during the cross-wire process, etc.

A hydrophobic film of zirconium acylate polymer covers the surface of the copper powder, but it cannot completely cover the surface of the copper powder.
Gaps and cracks occur in the membrane. Higher carboxylic acid esters have easily hydrolyzable alkoxy groups, so they undergo a transesterification reaction with adsorbed water on the surface of copper powder, bind to the surface of copper powder through electrostatic approach, and are transesterified by the lipophilic acylate group. , a hydrophobic film of carboxylic acid ester is formed in the gap to form a dense film on the surface of the copper powder.

Therefore, in an embodiment in which a mixture of a zirconium acylate polymer and a higher carboxylic acid ester is coated, since the mixture of the zirconium acylate polymer and a higher carboxylic acid ester is coated, it does not react with the adsorbed water on the surface of the copper powder or the coating. A strong film that does not impair conductivity can be formed by electrostatic approach or the like.

〔Effect of the invention〕

This invention provides the following effects.

The copper powder for conductive paint according to claim 1 improves the conductivity and environmental resistance of the copper powder itself and the paint without reducing the electromagnetic shielding effect.

That is, the organic amine can improve the heat resistance and moisture resistance of the copper powder, and suppress discoloration and generation of patina. Also,
Since an organic zirconium compound is used, the coating composition is endowed with excellent electrical conductivity, and also has improved environmental resistance and adhesion to the substrate.

In the copper powder for conductive paint according to claims 5.13 and 16, in addition to the organic amine, a zirconium acylate polymer and a higher carboxylic acid ester are used. further improves the conductivity and environmental resistance of

〔Example〕

This invention will be specifically explained by the following examples.

Experimental Material A: Copper Powder A dendritic electrolytic copper powder (manufactured by Mitsui Mining & Smelting Co., Ltd., MF-D2) shown in Table 1 was used.

Table 1 Apparent Density 0.72g/(To) 3 Tap Density 1. 30g/an3 specific surface area
0.40M/g average particle size 1168μ
m b, Resin binder Table 2 shows the resin binder used in the experiment.

Table 2 Type Product Name Acrylic Resin Acrybond BC-415B Phenol Resin PL-2210C Hydroxyalkylamine (Rust Inhibitor) Table 3 shows the hydroxyalkylamine according to the present invention used in the experiment.

Table 3 No. Hydroxyalkylamine 3-1
Monoethanolamine 3-2 N,N-dimethylethanolamine 3-
3 N,N-diethylethanolamine 3-4
Jetanolamine 3-5 N-butyl jetanolamine 3-6
Triethanolamine 3-7 Triisobrobanolamine 3-8
Isopropanolamine d, Dispersant A reaction mixture of the metal alkoxide shown in Table 4 and a higher fatty acid was prepared, and dispersant samples No. 4-1 to 13 were prepared.

No.

Table 4 Reaction raw materials and number of moles Metal alkoxide Higher fatty acid pyruzirconium pyruzirconium pyruzirconium pyruzirconiumoate tetra-n-bu 1 tyruzirconium isostearate tetraisobutylzirconium isostearate tetra-t-bu 1 tyruzirconium isostearate 4 -10 Tetra-n-bu 1 oleityl zirconium acid 4-11 Tetra-n-bu 1 oleityl zirconium acid No. 5 shown in Table 5. Higher carboxylic acid esters of 5-1 to 9 were used.

Table 5 Ester No. Higher carboxylic acid ester 5-1
Isopropyl stearate 5-2 n-butyl isostearate 5-3 Isopropyl valmitate 5-4 〇-butyl mystilate 5-
5 Isopropyl laurate 5-6 -butyl caprate 5-7 Isopropyl oleate 5-8 n-butyl linoleate 5-9
Isopropyl Riruinate f, Comparative Dispersants For comparison purposes, the dispersants of the comparative samples in Table 6 below were used.

No.

Table 6 Comparative Dispersant Isopropyl Tridodecyl Benzene Sulfonyl Titanate Anthrazine 6-6 Oleic Acid g6 Comparative Amine For comparison purposes, the amine rust inhibitors of the comparative samples in Table 7 below were used.

Table 7 No. Amine 7-1 Cetylamine 7-2 Myristylamine 7-3 Amylamine 7-4 Allylamine 7-5 Ethylamine 7-6 Cyamylamine 7-7 Cyclohexylamine Experimental Example 1 Table 1 from which the conductive oxide film of the conductive paint was removed Copper powder, the resin binder in Table 2, the amine in Table 3, the organic zirconate compound in Table 4, the higher fatty acid ester in Table 5, and the solvent (
Acrylic resin (Acrybond B) is used as a resin binder.
A conductive paint was prepared in the usual manner using toluene for C-415B (manufactured by Mitsubishi Rayon) and methylcarpitol for phenolic resin (solid content 60% by weight, manufactured by Gunei Chemical Co., Ltd.). . The obtained conductive paint was printed on an acrylic board or a phenol board in a length of 20 cm using a screen printing machine.

Width 0. A conductor circuit having a film thickness of 1c+n and a film thickness of 40±10 μm was formed and dried at 50° C. for 30 minutes or at 150° C. for 30 minutes. The volume resistivity of the cured circuit (coating film) was determined by il'PI.

In addition, the processing amount of amine, organic zirconate compound, and higher fatty acid ester is 0,01.0.
1.0.5.1.0.3.0.5.0.10.0% by weight
The copper powder content is 7% relative to the solid content of the resin binder.
It was 3% by weight.

As a result, the coating film of the conductive paint according to the present invention is 1x10
It had a volume resistivity of ˜4×10′Ω·mm.

On the other hand, for comparison, the same as above except that the comparative dispersant of Table 6 was used instead of the organic zirconate compound of Table 4, and the comparative amine of Table 7 was used instead of the amine of Table 3. A conductive paint was prepared and the volume resistivity of the paint film was measured.

The coating film of the comparative conductive paint is at least 8×10-4 to 9
It shows a volume resistivity of X10-4Ω, and most of them are 1×1
It showed a volume-specific paper resistance of 0 to 2×10′Ω・(up to).

From these results, it was found that the conductive coating composition prepared according to the present invention has excellent conductivity.

Experimental Example 2 Heat-resistant, moisture-resistant, and aging properties of the coating film A conductive paint coating (conductor circuit) substrate prepared in the same manner as in Experimental Example 1 was
2 under a high temperature of 85℃ and a humidity environment of 60℃/95%RH.
The coating film was left to stand for 000 hours, and the rate of change in resistance (%) of the coating film was measured.

As a result, most of the conductive paint films prepared and formed according to the present invention showed a change rate of around 5%, and at most only 7%, in a high temperature environment of 85°C. Also, 6
In a humidity environment of 0℃/95%RH, most of the
Before and after, the rate of change was only 4% at most.

In contrast, the conductive paint coatings from comparative samples showed a change rate of at least 20% and at most 150-200% in a high temperature environment of 85°C. In addition, under a humidity environment of 60°C and 795%RH,
exhibiting a rate of change of at least 15% and at most 80-130
% change rate is shown.

From these results, it can be seen that the coating film of the conductive paint prepared according to the present invention is extremely excellent in heat resistance and moisture aging resistance.

Experimental Example 3 Salt Water Resistance A conductive paint film (conductor circuit) substrate prepared in the same manner as in Experimental Example 1 was coated with a 5% by weight NaCl aqueous solution (liquid temperature 35±2
A salt water spray test was conducted for 72 hours using a 72-hour temperature (°C), and the development of patina and the rate of change in resistance (%) of the coating film were measured.

As a result, the coating film of the conductive paint prepared according to the present invention showed no discoloration and no patina. Also,
The coating film of the conductive paint is lXl0-4~9X10'Ω・(2
).

On the other hand, the conductive paint film of the comparison sample changed color to brownish-brown and developed a severe patina. Moreover, the coating film of the conductive paint had a volume resistivity of 2×10 −3 to 1×10 −”Ω·.

From the above results, it was found that the coating film of the conductive paint prepared according to the present invention has excellent salt water resistance.

Experimental Example 4 Adhesion of Coating Film A conductive paint prepared in the same manner as in Experimental Example 1 was formed into a 2X2+1111 pad coating film on paper phenol, glass epoxy, ABS, and acrylic substrates using a screen printing machine. After drying, a room-temperature curing epoxy resin is applied to the coating film. 9 by gluing 5φam tin-plated copper wire
0@Pool test was conducted.

The thickness of the coating film was 50±10 μm, and the number of test pads was 20.

As a result, the peel strength of the pad coating of the conductive paint prepared according to the present invention was 0.7 to 1.4 kg/mnf.
Met.

On the other hand, the peel strength of the pad coating of the comparative conductive paint was only 0.3 to 0.6 kg/m rrr.

From this result, it was found that the coating film of the conductive paint prepared according to the present invention had excellent adhesion to the substrate.

Experimental Example 5 The copper powder shown in Table 1 from which the rust-preventive oxide film has been removed was mixed with the amine shown in Table 3, the organic zirconate compound shown in Table 4, and the higher fatty acid ester shown in Table 5 using a ■ type blender. were mixed in this order and subjected to surface coating treatment.

After drying the copper powder, the temperature of 85℃, 60℃/95%
The copper powder was left in a humid environment of RH for 56 days, and the copper powder was observed for discoloration and patina.

The processing amounts of the amine and the organic zirconate compound are 0,01.0.1.0, 5.1.0.3.0.5, respectively.
It was 0.10.0% by weight.

As a result, the copper powder prepared according to the present invention showed no discoloration and no patina.

On the other hand, in the comparative coated copper powder using a comparative sample, discoloration to brownish brown was observed, and patina was also observed.

From the above results, it was found that the copper powder treated according to the present invention has excellent rust resistance.

Experimental Example 6 Conductivity of Conductive Paint Surface-coated copper powder coated in the same manner as in Experimental Example 5 and the second
The resin binder in the table and the solvent (toluene in the case of acrylic resin (Acrybond BC-415B, manufactured by Mitsubishi Rayon) as the resin binder, methyl carpi in the case of phenolic resin (solid content 60% by weight, manufactured by Gunei Chemical Co., Ltd.)) A conductive paint was prepared using a conventional method.

The obtained conductive paint was printed on an acrylic board and a phenol board using a screen printing machine, with a length of 20co+s and a width of 0.1cm, and a film thickness of 40mm.
A conductor circuit of ±10 μm was formed and dried at 50° C. for 30 minutes or at 150° C. for 730 minutes. The volume resistivity of the cured circuit (coating film) was measured.

The coating amount of the amine, organic zirconate compound, and higher fatty acid ester is 0.01.0.
1.0.5.1.0.3.0.5.0.10.0% by weight
The copper powder content is 7% relative to the solid content of the resin binder.
It was 3% by weight.

As a result, the coating film of the conductive paint according to the present invention is lXl0
It had a volume resistivity of ~4X10-'Ω·(up to), and exhibited a volume resistivity of not less than 9×10-5–4×10−’Ω·.

On the other hand, for comparison, the same as above except that the comparative dispersant of Table 6 was used instead of the organic zirconate compound of Table 4, and the comparative amine of Table 7 was used instead of the amine of Table 3. A conductive paint was prepared and the volume resistivity of the paint film was measured.

The coating film of the comparative conductive paint is not a little 8X10 to 9X1
It shows a volume resistivity of 0-4Ω・■, and most of them are 1×10~
The volume resistivity of the mouth was 2×10′Ω.

From these results, it was found that the conductive coating composition prepared according to the present invention has excellent conductivity.

Claims (8)

[Claims] 1. Copper powder for conductive paints coated with organic zirconate compounds and hydroxyalkylamines. 2. The copper powder for conductive paint according to claim 1, wherein the hydroxyalkylamine is represented by the following structural formula. (R^1)_nN(R^2)_3_-_n (wherein, R^1 represents a hydroxyalkyl group having at least one hydroxyl group, R^2 represents an alkyl group or hydrogen, and n is 1≦ (represents an integer of n≦3) 3. The copper powder for conductive paint according to claim 1 or 2, wherein the organic zirconate compound is represented by the following general formula. (RO)_x-Zr-(OR')_4_-_x (in the formula,
RO is an easily hydrolyzable organic group, OR' is an organic group that is hardly hydrolyzable and lipophilic, and x is an integer from 1 to 3) 4. The copper powder for conductive paint according to claim 1, wherein the organic zirconate compound is a zirconium acylate polymer. 5. 5. The copper powder for conductive paint according to claim 4, wherein a higher carboxylic acid ester comprising a higher fatty acid acylate group and an easily hydrolyzable alkoxy group is used in combination with the organic zirconate compound. 6. A conductive coating composition containing a mixture of a zirconium acylate polymer and a higher carboxylic acid ester as an organic zirconate compound, a copper powder coated with a hydroxyalkylamine, a resin binder, and a solvent. 7. A conductive coating composition in which an organic zirconate compound and a hydroxyalkylamine are added to a mixed system of copper powder, a resin binder, and a solvent. 8. 8. The conductive coating composition according to claim 7, wherein a mixture of a zirconium acylate polymer and a higher carboxylic acid ester is added.