JPH07331126A - Coating composition - Google Patents

Abstract

PURPOSE:To provide a conductive coating material which suffers no reduction in conductivity under various environmental conditions over a long period of time. CONSTITUTION:A coating composition containing a metallic copper powder or a copper alloy powder, and a thermoplastic resin and/or a thermosetting resin, which contains at least one acylphosphonic acid represented by the general formula R-CO-PO(OM1)(OM2) (wherein R is 3-21C linear or branched alkyl or alkenl, or optionally substituted 6-31C aryl; and M1 and M2 may be the same or different and are each H or cation).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a conductive coating material containing metallic copper powder or copper alloy powder as a main conductive material, and in which the conductivity is not deteriorated for a long period of time under various environmental conditions.

[0002]

2. Description of the Related Art When an electromagnetic wave enters an electronic device such as a communication device or a computer from the outside, its function is hindered, and the electromagnetic wave generated from the device itself such as a microwave oven causes various obstacles to other electronic devices and human body. Bring For this reason, in recent years, with the spread of electronic devices, social demands for electromagnetic wave shields have been increasing in order to prevent the intrusion of electromagnetic waves and the leakage of electromagnetic waves generated from the devices themselves. As a method for imparting electromagnetic wave shielding properties, a method has been proposed in which a conductive coating material is applied to a plastic electronic device housing to prevent electromagnetic waves from entering from the outside and to confine electromagnetic waves generated from the device itself. The mainstream of this conductive paint is a conductive fine powder of nickel, carbon, silver or the like mixed and dispersed in an organic binder. However, silver is preferable in that it has excellent conductivity and is stable against oxidation and retains stable conductivity for a long period of time, but it is economically disadvantageous when used in a coating material for electromagnetic shielding because it is expensive. . Further, carbon is inexpensive but inferior in conductivity, and nickel is expensive and inferior in conductivity. Also,
Copper is cheaper and more conductive than nickel, but is oxidized in the coating composition and forms a non-conductive oxide film on the surface of the fine particles, so that the conductivity of the coating film is time-consuming. The electromagnetic wave shielding property tends to decrease as time goes by. Therefore, until now, even if the conductive fine powder of nickel, carbon, silver or the like was used, a conductive paint having a good balance between performance and price could not be obtained. In order to prevent the conductivity of the coating composition from decreasing, the present inventors have first improved the antioxidative stability of the metal powder, and have stable conductivity and shielding effect even after storage for a long period of time. A derivative-containing conductive paint was developed (JP-A-63-286478). Although a coating film having excellent conductivity performance can be obtained by applying this conductive paint after storage for a long time after preparation, the conductivity performance of the coating film was not sufficient under high temperature and high humidity conditions.

[0003]

SUMMARY OF THE INVENTION The present invention improves the antioxidative stability of metallic copper powder and / or copper alloy powder contained in a paint, thereby making it possible to achieve conductivity over a long period of time under various environmental conditions. It is an object of the present invention to provide a conductive paint that does not deteriorate.

[0004]

The present invention is a coating composition containing metallic copper powder and / or copper alloy powder, and a thermoplastic resin and / or a thermosetting resin, which has the following general formula (I):
The present invention provides a coating composition containing at least one kind of acylphosphonic acid represented by _{R-CO-PO (OM 1} ) (OM 2) (I) ( wherein, R represents a linear or branched alkyl or alkenyl group having 3 to 21 carbon atoms, or carbon atoms 6-31
Represents an aryl group which may have a substituent, M ₁ and M ₂ represent hydrogen or a cation, and may be the same or different).

In the above general formula (I), R has 3 carbon atoms.
To 21, preferably 7 to 19 linear or branched alkyl group or alkenyl group, or 6 to 31 carbon atoms
Is an aryl group which may have a substituent. Further, the aryl group is preferably a naphthyl group, a phenyl group, and an alkyl-substituted or alkenyl-substituted product thereof. For example, an alkylphenyl group having a C1-8 alkyl group or an alkenyl having a C2-8 alkenyl. A phenyl group can be mentioned.

M₁And M₂Is hydrogen or cation
And may be the same or different. this
The cation may be either an inorganic cation or an organic cation.
Well, examples are sodium, potassium, and lithium.
Alkali metal cations such as aluminum, magnesium, calcium
Alkaline earth metal cations such as aluminum, and general formula N
(R ₁)_FourAmmonium cation represented by (R₁Haso
Independently hydrogen, alkyl group, alkenyl group
Is an aryl group or a substitution product thereof, and the substitution product
Is a halogen, hydroxyl group, amino group, amide group,
Alkyl groups substituted by substituents such as sil groups, alkene
Group and aryl group. . ). The general formula
Specific examples of the acylphosphonic acid derivative represented by (I) will be given.
Butyrylphosphonic acid, hexanoylphosphonic acid
Acid, octanoylphosphonic acid, decanoylphosphonic acid,
Lauroylphosphonic acid, stearoylphosphonic acid, ole
Oroylphosphonic acid, benzoylphosphonic acid, methyl ester
Nazoylphosphonic acid, lauroylphosphonic acid monosoda
Salt, calcium lauroylphosphonate, lauroylpho
Examples include sulfonic acid triethanolamine salt.

In the conductive coating composition of the present invention, the amount of the acylphosphonic acid derivative used is 100 as the metallic copper powder, the copper alloy powder or a mixture thereof (hereinafter referred to as copper powder).
The amount is preferably 0.1 to 10 parts by weight, and more preferably 0.3 to 8 parts by weight. When the amount used is less than 0.1 part by weight, the antioxidant property of the copper powder in the coating film is insufficient.
Even if added in an amount of more than 10 parts by weight, the effect is not improved and, on the contrary, it is difficult to obtain a uniform coating material, and the physical properties of the coating film are deteriorated. Next, the copper powder and the resin component used in the present invention will be described. The metallic copper powder used in the present invention is not particularly limited, and metallic copper powder obtained by any of the electrolysis method, the spray method and the reduction method can be used. Further, the copper alloy powder can be used without particular limitation as long as the copper content is 50% or more, and examples thereof include alloys of copper and zinc, tin, nickel or silver.
Moreover, you may mix and use the powder of metallic copper and a copper alloy as needed. The particle size of the copper powder is usually Tyler mesh of 150 mesh or less, preferably 200 mesh or less. The content of the copper powder is an amount necessary for the composition to exhibit conductivity, and is 35 to 94% by weight, preferably 50 to 90% by weight, based on the total weight of the resin component and the copper powder. It is particularly preferably in the range of 60 to 90% by weight.

The range is limited to 35% by weight.
If it is less than 94% by weight, the conductivity is low, and if it exceeds 94% by weight, the physical properties of the coating film are deteriorated. The resin component used in the present invention is a thermoplastic resin and / or a thermosetting resin,
It includes everything used for general paints. Examples of this thermoplastic resin include thermoplastic resins such as acrylic resin, vinyl chloride resin, and ethylene-vinyl acetate resin, and examples of thermosetting resins include thermosetting acrylic resin and polyurethane resin. , Epoxy resin, phenol resin, unsaturated polyester resin, melamine resin, alkyd resin and the like. In the coating composition of the present invention,
In addition to the above components, a diluent solvent can be used. Examples thereof include alcohols such as butyl alcohol and isopropyl alcohol, ketones such as methyl isobutyl ketone, esters such as butyl acetate, aromatic hydrocarbons such as toluene and xylene, and ethers such as butyl cellosolve. There is a general paint solvent. If necessary, a thickener, an anti-skinning agent, an anti-sagging agent, a coupling agent, a curing accelerator, an ultraviolet absorber, an anti-settling agent, etc. are added to the conductive coating composition of the present invention.

In the method for adding an acylphosphonic acid derivative in the case of producing the conductive coating material of the present invention, the acylphosphonic acid derivative is added and mixed in advance with the resin and the organic solvent used, and then copper powder is added and mixed. And a method of mixing a copper powder treated in a mixture of an acylphosphonic acid derivative and an organic solvent with a resin and an organic solvent, a method of adding an acylphosphonic acid derivative to the copper powder, a resin and an organic solvent mixture, etc. is there. Next, the present invention will be described with reference to examples. The present invention is not limited to such embodiments.

[0010]

[Examples] In the examples, the conductivity is measured according to JIS K-6911.
The surface resistance value (Ω) was evaluated by the measurement method of. The acylphosphonic acid in the examples was produced by reacting carboxylic acid chloride with an equivalent amount of phosphorous acid at a temperature of 110 to 130 ° C. for 4 hours. The salt-type acylphosphonic acid was produced by reacting the synthesized acylphosphonic acid with various cations. [Examples 1 to 10] Electrolytic copper powder (Fukuda Metal: FCC-110) 1
Conductive by stirring and mixing 00 parts by weight, 133 parts by weight of a toluene solution containing 25% by weight of acrylic resin (BR-80 manufactured by Mitsubishi Rayon), 3 parts by weight of the acylphosphonic acid derivative shown in Table 1 and 75 parts by weight of toluene. I got a paint. The above paint was applied on a polyester film so that the dry coating film would be 100 μm, and dried at 60 ° C. for 30 minutes.

[Comparative Examples 1 to 3] Instead of the acylphosphonic acid derivative, 3 parts by weight of acetylphosphonic acid in Comparative Example 1 and 3 parts by weight of 1-hydroxydodecylidene-1,1-diphosphonic acid in Comparative Example 2 were used. Parts were used, and in Comparative Example 3, a coating composition and a coated polyester film were produced in the same manner as in Example 1 except that a substitute chemical was not used. Then, the surface resistance values of the coated polyester films produced in Examples 1 to 10 and Comparative Examples 1 to 3 were measured. Furthermore, in order to investigate the heat resistance and moisture resistance of the coating film, the surface resistance value after leaving it in the air at 100 ° C for 20 days and the surface resistance value after leaving it for 20 days under the conditions of 60 ° C and 90% RH Was measured. The measurement results are shown in Table 2. In the coated polyester films obtained in Examples 1 to 10 according to the present invention, the surface resistance value immediately after drying was about 0.5 Ω, respectively, and compared with the composition containing no acylphosphonic acid derivative of Comparative Example 3, It showed an excellent value of 1/10. Further, in the heat resistance and humidity resistance tests, in Comparative Example 3, the copper powder was oxidized and the conductivity was remarkably lowered, whereas in Examples 1 to 10, no change due to the environment resistance test was observed. Further, the composition of Comparative Example 1 is insoluble in toluene and thus has no effect of addition, and the composition of Comparative Example 2 has a problem in moisture resistance.

[0012]

[Table 1] Table 1 ─────────────────────── Example Acylphosphonic acid 1 Hexanoylphosphonic acid 2 Octanoylphosphonic acid 3 Lauroylphosphonic acid 4 Stearoyl Phosphonic acid 5 Oleoylphosphonic acid 6 Benzoylphosphonic acid 7 Laurolyuphosphonic acid Na 8 Laurolylphosphonic acid 2Na 9 Lauroylphosphonic acid Triethanolamine salt 10 2-Ethylhexanoylphosphonic acid Comparative example 1 Acetylphosphonic acid 21-Hydroxide Decylidene-1,1-diphosphonic acid 3 None

[0013]

[Table 2] Table 2 (1) ────────────────────────────────── Surface resistance (Ω) Actual Example 1 2 3 4 5 6 7 Immediately after drying 0.42 0.43 0.38 0.40 0.45 0.48 0.50 100 ° C, 20 days 0.43 0.42 0.39 0.40 0.43 0.50 0.52 60 ° C, 90% RH 20 days 0.42 0.44 0.40 0.41 0.44 0.51 0.50 Table 2 (2) ─ ───────────────────────────────── Surface resistance (Ω) Actual Example Comparison Example 8 9 10 1 2 3 Immediately after drying 0.55 0.55 0.45 3.5 0.42 3.8 100 ° C, 20 days 0.55 0.54 0.44 4 × 10 ³ 0.42 5 × 10 ³ 60 ° C, 90% RH 20 days 0.54 0.56 0.43 18.4 3.8 11.2

[Examples 11 to 20] 100 parts by weight of electrolytic copper powder (FCC-110 manufactured by Fukuda Metals Co., Ltd.), 33 parts by weight of various resin components (as solid content) shown in Table 3, 175 parts by weight of solvent and the same table. The indicated amount of lauroylphosphonic acid was added and mixed by stirring to obtain a conductive paint. Painting and drying (curing) as in Example 1.
Then, the surface resistance value after standing in the air at 100 ° C. for 20 days and the surface resistance value after standing for 20 days at 60 ° C. and 90% RH were measured. The results obtained are shown in Table 4. [Comparative Examples 4 to 5] In Comparative Examples 4 and 5, a conductive coating material was obtained in the same manner as in Example 11 except that lauroylphosphonic acid was not used, and the surface resistance value was measured.

[0015]

[Table 3] Table 3 ─────────────────────────────── Example Resin component Lauroylphos solvent Solvent phonic acid content 11 Acrylic Resin 0.1 Toluene 12 Ibid 0.3 Ibid 13 Ibid 2 Ibid 14 Ibid 5 Ibid 15 Ibid 8 Ibid 16 Ibid 10 Ibid 17 Phenol butyral resin 3 Butylcellosolve 18 Ibid 5 Ibid 19 Phenol epoxy resin 2 Ibid 20 Ibid 5 Ibid 5 Comparative example 4 Phenolbuty Lahr resin 0 ibid 5 phenolic epoxy resin 0 Same as above

[0016]

[Table 4] Table 4 (1) ──────────────────────────────── Example 11 12 13 14 15 16 17 Drying temperature ℃ 60 60 60 60 60 60 60 Drying time (Hr) 0.5 0.5 0.5 0.5 0.5 0.5 150 Surface resistance (Ω) Immediately after drying 2.4 0.43 0.39 0.41 0.44 0.50 0.38 100 ℃, 20 days 2x10 ² 5.2 0.41 0.40 0.43 0.55 0.40 60 ℃, 90% RH 20 days 1.5 0.9 0.40 0.41 0.44 0.57 0.39 Table 4 (2) ───────────────────────────── Example Comparative Example 18 19 20 45 Drying temperature ℃ 60 60 60 60 60 Drying time (Hr) 0.5 0.5 0.5 0.5 0.5 Surface resistance (Ω) Immediately after drying 0.41 0.50 0.45 ＞ 10 ⁸ ＞ 10 ⁸ 100 ℃, 20 days 0.45 0.54 0.48 ＞ 10 ⁸ ＞ 10 ⁸ 60 ℃, 90% RH 20 days 0.44 0.54 0.46 ＞ 10 ⁸ ＞ 10 ⁸

Acrylic resin: Mitsubishi Rayon BR-80 Phenol butyral resin: Dainippon Ink's Priofen 5030-40-K Phenol epoxy resin: Dainippon Ink's Priofen TD-447 [Examples 21 to 29] 100 parts by weight of brass powder having different copper contents, 33 parts by weight of acrylic resin (solid content), lauroylphosphonic acid in the amounts shown in Table 5, and 175 parts by weight of toluene as a solvent were added, and the mixture was stirred and mixed to make it conductive. Got the paint. Painting and drying (curing) as in Example 1.
Then, the surface resistance value after standing in air at 100 ° C. for 20 days and the surface resistance value after standing for 20 days at 60 ° C. and 90% RH were measured. The obtained results are shown in Table 6.

[0018]

[Table 5] Table 5 ────────────────────────────────── Example 21 22 23 24 25 26 27 28 29 30 Brass powder Cu: Zn = 90: 10 100 100 100 100 100 0 0 0 0 0 Cu: Zn = 70: 30 0 0 0 0 0 100 100 100 100 100 Lauroylphosphonic acid 0.3 1 3 5 8 0.3 1 3 5 8

[0019]

[Table 6] Table 6 (1) Surface resistance (Ω) Example 21 22 23 24 25 26 Immediately after drying 0.57 0.53 0.47 0.45 0.44 0.58 100 ° C, 20 days 0.55 0.53 0.48 0.47 0.43 0.55 60 ° C, 90% RH 20 days 0.70 0.63 0.50 0.48 0.47 0.68

Claims (1)

[Claims] 1. A coating composition containing metallic copper powder and / or copper alloy powder and a thermoplastic resin and / or thermosetting resin, wherein at least an acylphosphonic acid represented by the following general formula (I) is used. A coating composition comprising one kind. _{R-CO-PO (OM 1} ) (OM 2) (I) ( wherein, R represents a linear or branched alkyl or alkenyl group having 3 to 21 carbon atoms, or carbon atoms 6-31
Represents an aryl group which may have a substituent, M ₁ and M ₂ represent hydrogen or a cation, and may be the same or different).