JPS5832668A - Electrically conductive coating material - Google Patents

Abstract

PURPOSE:An electrically conductive coating material, prepared by incorporating an electrically conductive material powder and an antistatic agent in a specific proportion in an organic binder, capable of improving the dispersion stability of the electrically conductive material powder and preventing the flocculation and improving the deterioration in the electric conductivity during the storage thereof. CONSTITUTION:1-10pts.wt. electrically conductive material powder, e.g. a metallic powder such as silver or aluminum powder, metallic powder prepared by coating the surface of a pigment, glass beads, etc. with a metal, e.g. silver or copper, or a carbonaceous material powder, e.g. graphite, is mixed and dispersed in 100pts.wt. (solid content) organic binder, e.g. an alkyd resin or acrylic resin. A pigment may be simultaneously mixed and dispersed therein if necessary. 0.1-10pts.wt. antistatic agent is then mixed and dispersed in the resultant dispersion to give the aimed coating material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a conductive paint with improved conductivity deterioration during storage.

Conductive paints prepared by mixing and dispersing conductive material powders such as silver powder, copper powder, carbon black, and graphite in an organic binder are well known and are used as electrical materials. No. 91945 discloses a method of applying conductive paint to insulating parts such as slag adhesion parts of arc welding of automobile bodies, and then uniformly applying electrodeposition coating. -9
No. 6031 states that steel materials used for automobile bodies etc. are coated with conductive paint in advance to prevent rust.
A method of applying electrodeposition coating after molding is disclosed.

The conductive paint used in these cases must be able to be electrodeposited uniformly and smoothly on the coating film, but if the conductive paint is stored for a long time, Among them, the electrical conductivity of the resulting coating film is significantly reduced, making it impossible to perform uniform and smooth electrodeposition coating.

In these conductive paints, during the drying and solidification process due to evaporation of the solvent from the paint film, the conductive substance powders connect to form "bridges", and electricity flows through these "bridges". However, the conductive material powder aggregates during storage.

Then, the polymer used as the organic binder is adsorbed around the aggregates, and the aggregates are separated from each other by a thick insulating layer, resulting in a significant decrease in the electrical conductivity of the coating film.

Therefore, when using conductive paint, it is necessary to mix a relatively large amount of conductive substance powder in order to compensate for the decrease in the conductivity of the coating film. However, it has had the disadvantage of causing deterioration in physical properties and painting workability.

In view of the above-mentioned current situation, the present inventors conducted unique research to develop a conductive paint with good storage stability and coating workability.
By blending an antistatic agent with the conductive powder, even if the amount of the conductive powder is relatively small,
The antistatic agent is adsorbed on the surface of the conductive substance powder, increasing the stability of the seven-dispersion process, preventing agglomeration of the conductive substance powder, and at the same time reducing the volume resistance of the organic bicedar, resulting in good conductivity over a long period of time. The present invention has been made based on this discovery.

That is, the present invention has 1 organic binder (solid content) 10
0 parts by weight, 1 to 10 parts by weight of a conductive material powder, and 0.1 to 10 parts by weight of an antistatic agent.

Examples of the organic binder used in the present invention include resins commonly used in the paint field, such as alkyd resins, acrylic resins, amino resins, epoxy resins, epoxy ester resins, polyurethane resins, petroleum resins, cellulose resins, vinyl resins, Examples include polyamide resin, polyester resin, polyether resin, polybutadiene resin, phenol resin, etc., and one or more of these can be used.

゛The conductive material powder used in the present invention is
For example, metal powders such as silver powder, copper powder, tin powder, and aluminum powder, pigments, and so-called "metal coated powders" in which the surface of glass beads is coated with metals such as silver, copper, tin, and aluminum; graphite, carbon black, etc. Examples include carbonaceous powder, and one or more of these can be used.

These conductive material powders contain an organic binder (solid content)
It is used in an amount of 1 to 10 parts by weight per 100 parts by weight. If the amount of conductive material powder is less than 1 part by weight per 100 parts by weight of organic binder (solid content), "bridges" will not be formed uniformly, and even if an antistatic agent is added, the coating will not be uniform. Since conductivity cannot be obtained, electrodeposition cannot be applied uniformly and smoothly on the coating film, and if the amount exceeds 10 parts by weight,
When stored for a long time, the decrease in conductivity is small, but the physical properties
Paint workability will be greatly reduced.

Examples of the antistatic agent used in the present invention include anionic, anionic, amphoteric, and nonionic surfactants, and one or more of these may be used. . - These antistatic agents contain organic bi/goo (solid content) 1G (1 part by weight, 0
．． 1 to 10 parts by weight are used. If the amount of antistatic agent is less than 0.1 part by weight relative to 10 parts by weight of the organic binder (solid content), it will not contribute sufficiently to stabilizing the conductivity of the coating film, and if it exceeds 10 parts by weight, , defects such as bleeding onto the surface of the coating film and a decrease in water resistance occur.

In addition to the above-mentioned organic binder, conductive substance powder, and antistatic agent, the conductive paint of the present invention may also contain pigments such as coloring pigments, extender pigments, and rust-preventing pigments, and surface conditioners. Additives can be added, and there are no restrictions on their types and amounts.

In order to produce the conductive paint of the present invention, a conductive substance powder is first mixed with an organic Mix and disperse in binder. At that time, pigments may be mixed and dispersed at the same time, if necessary. Next, the antistatic agent is mixed and dispersed, and the antistatic agent may be mixed and dispersed before, after, or in the middle of the above mixing and dispersion.

Then, if necessary, the viscosity 4 is adjusted by mixing and dispersing additives or diluting with a solvent or the like.

The conductive paint of the present invention can be applied by conventional methods such as air spray coating, airless spray coating, electrostatic coating, dip coating, flow coating, and brush coating, and can be cured at room temperature, heated, or exposed to moisture. Curing methods such as curing, catalytic curing, ultraviolet curing, and electron beam curing can be selected depending on the characteristics of the organic inder resin used and the coating conditions, but the coating film may not be completely cured. It may be in a half-f or uncured state. - Since the conductive paint of the present invention exhibits very little conductivity deterioration during storage, it can be stored for a long period of time, then applied to an object to be coated such as a steel plate, and electrodeposited on the resulting coating film. This method has the remarkable advantage that a uniform and smooth electrodeposition coating film can be obtained.

Next, the present invention will be explained in more detail by giving Examples and Comparative Examples. The parts in the columns indicate parts by weight, and the percentages in the columns indicate weight %.

Example 1 An organic binder was produced based on the formulation shown in Table 1.

Next, the conductive paint was placed in a sealed container, then placed in a constant temperature bath at 50° C. and stored for 30 days.

During that time, the conductive paint immediately after production (before storage), 1 day, 3 days, 7 days, 15 days, and 30 days was coated with cellosolve acetate; Ford Caddam 4 viscosity (20℃) 2
Diluted to 0 seconds, test plate (cold rolled steel plate with thickness 0.8cm)
Then, apply with air spray (dry film thickness 15μ), 140℃
After heating and drying for 5 minutes, immerse it in an electrodeposition paint (Nippon Oil & Fats ■, cationic electrodeposition paint, Aqua A 4120) bath, and apply the electrodeposition at a bath temperature of 29°C, a voltage of 240V, and an electrodeposition time of 3 minutes. A test piece was obtained by applying a coating, washing with water, and heating and drying at 175°C for 26 minutes.

The obtained test pieces were tested for dry film thickness (b) and smoothness of the electrodeposition coating, and the test results are shown in Table 2.

Example 2 An organic binder was produced based on the formulation shown in Table 1.

Then, in the same manner as in Example 1, conductive paint was applied by air spray, heated and dried (dipped in an electrodeposition paint bath, applied with electrodeposition, washed with water, heated). After drying, a test piece was obtained. "The obtained test piece was subjected to the same test as in Example 1, and the test results are shown in Table 2.

Example 3 Based on the formulation shown in Table 1, 8.2 parts of conductive substance powder and 1.2 parts of antistatic agent were added to 100 parts of organic inder (solid content). jhf, a combined conductive paint was produced.

Next, in the same manner as in Example 1, a conductive paint was applied by air spray, dried by heating, immersed in electrodeposition paint, applied with electrodeposition, washed with water, and dried by heating to obtain a test piece. I got it.

Regarding the obtained test piece, Example 1. ! : Similar tests were conducted and the test results are shown in Table 2.

Comparative Examples 1 to 3 The formulations shown in Table 1 (Comparative Example 1 is the formulation of Example 1, Comparative Example 3 is the formulation of Example 2, Comparative Example 3 is the formulation of Example 2,
conductive paints were produced based on the formulation of Example 3, in which the antistatic agent was replaced with an organic binder.

Next, in the same manner as in Example 1, a conductive paint was applied by air spray, dried by heating, immersed in an electrodeposition paint bath, applied with electrodeposition, washed with water, and dried by heating to obtain a test piece. I got it.

The obtained test pieces were subjected to the same tests as in Example 1, and the test results are shown in Table 2.

Table 2 Note: ○ indicates good, Δ is very good, × indicates poor, and XX indicates that the dry film thickness of the electrodeposition coating was 0 (no electrodeposition coating was formed), so the smoothness This indicates that it was impossible to measure.

Patent applicant: NOF Corporation -482-

Claims (1)

[Claims] A conductive coating material comprising 100 parts by weight of an organic binder (solid content), 1-10 parts by weight of a conductive substance powder, and 0.1-10 parts by weight of an antistatic agent.