KR102270647B1 - Method of forming electrode coating layer and method of electrode coating layer formed by the method - Google Patents

Abstract

The present invention relates to a method for forming a conductive paint coating film using a conductive mixture solution and to a conductive coating film formed thereby, comprising the steps of: (A) applying a top coating composition to a substrate; and (B) applying a conductive mixture solution when the top coating composition is cured by 40 to 70%; by including, desired conductivity and paint adhesion can be exhibited even with a small amount of conductive material compared to the prior art.

Description

Method of forming a conductive paint coating film using a conductive mixture solution and a conductive paint coating film formed thereby

The present invention relates to a method of forming a conductive paint film capable of exhibiting desired electrical conductivity and paint adhesion even when a small amount of a conductive material is used, and a conductive paint film formed thereby.

The conductive paint materials currently used in the industry are precious metals such as silver (Ag), gold (Au), and platinum (Pt), which are recognized as materials that can be directly applied to the printing process due to their high electrical conductivity and low oxidation properties. However, there are problems of high price and ion migration.

Alternative materials to overcome this problem are non-precious metals such as copper (Cu), nickel (Ni), aluminum (Al), etc., which have similar electrical conductivity to noble metals, can design ultra-fine wires, and have excellent economic feasibility. There are advantages. Nevertheless, non-precious metal-based metals are a major obstacle to commercialization due to the high oxidation degree of process cost increase. In order to solve this problem, a method such as covering the surface of a non-noble metal-based metal with a noble metal or an organic material has been introduced.

Recently, many paints incorporating a conductive filler without using the noble metal or non-noble metal material have been commercialized, but there is a problem in introducing carbon nanotubes with a high aspect ratio while studying the optimal spraying conditions for paint incorporating the conductive filler. confirmed that there is.

The carbon nanotubes are mixed with the paint in an amount of about 20 parts by weight or more (based on 100 parts by weight of the paint) and sprayed, and in this case, the viscosity of the paint increases and spraying is not performed properly.

In addition, as the viscosity of the paint increases, it is difficult to form a uniform coating thickness, and carbon nanotubes agglomerate on the surface, thereby greatly reducing the coating efficiency and marketability.

On the other hand, the conventionally widely used paint to which a spherical conductive filler is introduced is widely used in the industrial field, because aggregation of the filler and nozzle clogging do not occur during painting. However, in the paint to which the spherical conductive filler is introduced, about 50 parts by weight or more of the spherical conductive filler must be introduced with respect to 100 parts by weight of the paint for conductivity. .

Therefore, there is a need for a method of forming a conductive paint film that has excellent electrical conductivity and excellent paint adhesion, and does not cause aggregation of fillers.

Republic of Korea Patent No. 1933035 Republic of Korea Patent No. 1060946

An object of the present invention is to provide a method for forming a conductive paint film capable of exhibiting desired electrical conductivity and paint adhesion even when a small amount of a conductive material is used.

Another object of the present invention is to provide a conductive paint film formed according to the above forming method.

A method of forming a conductive paint film of the present invention for achieving the above object comprises the steps of (A) applying a top coating composition to a substrate; and (B) applying a conductive mixture solution when the top coating composition is cured by 40 to 70%.

The method may further include forming a primer layer by applying a primer composition to the substrate before applying the top coating composition in step (A).

The primer composition may be cured at 60 to 80° C. for 4 to 8 hours.

While curing the top coating composition at 60 to 80° C. in step (B), the conductive mixture may be applied at 40 to 70% curing.

The conductive mixture solution in step (B) may be a mixture of a conductive material having an aspect ratio of 10 to 100 and an organic solvent.

The conductive material and the organic solvent may be mixed in a weight ratio of 1: 5-15.

The conductive material may be used in an amount of 5 to 15 parts by weight based on 100 parts by weight of the top coating composition.

The conductive material and the organic solvent may be mixed for 60 to 120 minutes using an ultrasonic disperser.

The ultrasonic dispersion is carried out by ultrasonic dispersion for 60 to 120 minutes under the condition of 23 to 27 ° C. and a frequency of 15 to 25 kHz for 5 to 10 seconds, and resting for 1 to 5 seconds, with an amplitude of 20 to 40%. can be

The conductive material may be at least one selected from the group consisting of carbon nanotubes, graphene, and milled carbon fibers.

The organic solvent may be at least one selected from the group consisting of acetone, ether, ethanol and methanol.

After applying the conductive mixture in step (B), it may be cured at 60 to 80° C. for 4 to 8 hours.

In addition, the conductive paint film of the present invention for achieving the above other object may be prepared according to the method for forming the conductive paint film.

The conductive paint film of the present invention is prepared by applying a conductive mixture solution before the top coating composition is completely cured, so that it can exhibit desired electrical conductivity and paint adhesion even with a small amount of conductive material compared to the prior art, and there is no nozzle clogging.

The conductive paint film of the present invention can be used for lightning prevention by being provided in transportation means such as aircraft, automobiles, and trains.

1 is a flowchart illustrating a method of forming a conductive paint film according to an embodiment of the present invention.
2 is a view showing a cross-sectional view of a conductive paint film prepared according to an embodiment of the present invention.
3 is a view showing a method for measuring the surface electrical resistance in the present invention.

The present invention relates to a method of forming a conductive paint film capable of exhibiting desired electrical conductivity and paint adhesion even when a small amount of a conductive material is used, and a conductive paint film formed thereby.

In conductive paints currently on the market, fillers with an aspect ratio close to 1, such as carbon black or metal powder, are introduced. In the case of using a filler with an aspect ratio close to 1 mixed with the paint, 100 weight of the paint is used to increase conductivity. 50 parts by weight or more of the filler must be mixed with respect to parts, and in this case, the adhesion of the paint is reduced.

In addition, when the filler of the metal powder is used, there is a problem of promoting corrosion and increasing the weight of the overall structure.

In particular, when a filler having a high aspect ratio is introduced into the paint, the viscosity of the paint increases as well as entanglement of the fillers on the surface after application occurs.

In the present invention, a conductive material having a high aspect ratio is used, but in order to solve the above-mentioned problems, a conductive mixture solution containing a conductive material having a high aspect ratio is applied and cured before the top coating composition (paint) is cured. to form a coating film. As described above, the conductive paint film in which the conductive coating film is formed on the paint has higher paint adhesion compared to the conventional conductive paint film (a conductive material is mixed with paint), the conductive material does not agglomerate on the surface, and the electrical conductivity on the surface is increased.

Hereinafter, the present invention will be described in detail.

As shown in FIG. 1, the method of forming a conductive paint film of the present invention includes (A) applying a top coating composition to a substrate; and (B) applying a conductive mixture solution when the top coating composition is cured by 50 to 60%. The step (A) may further include a step (A`) of forming a primer layer by applying a primer composition to the substrate before applying the top coating composition.

First, in step (A), a top coating composition (paint) is applied to a substrate.

A conventional paint composition may be used as the top coating composition, and in the present invention, it is adhered to the substrate and does not fall off and has desired conductivity by the conductive coating film.

In addition, the substrate is not particularly limited as long as it can be provided with a conductive paint film. The conductive paint coating film of the present invention means that a conductive coating film is formed on the top coating.

Before applying the top coating composition, the primer composition is applied to the substrate and cured at 60 to 80° C. for 4 to 8 hours to form a primer layer, thereby further improving adhesion between the substrate and the top coating layer.

Next, in step (B), a conductive mixture is applied when the top coating composition is cured by 40 to 70%.

In the present invention, when 40 to 70%, preferably 50 to 60% of the top coating composition is cured, then the conductive mixture is applied and completely cured. When the curing degree of the top coating composition is less than the lower limit, the conductive material is not evenly applied and agglomeration may occur in some parts, and if it exceeds the upper limit, the adhesion and conductivity of the conductive coating film may be reduced. In particular, when the conductive mixture is applied after the top coating composition is completely dried, the conductive material is not attached to the top coating layer and thus has little conductivity, and the surface is caused by the conductive material remaining on a part of the top surface of the top coating layer. The high roughness deteriorates the quality of the product.

The conductive mixture solution of the present invention is a mixture of a conductive material having an aspect ratio of 10 to 100 and an organic solvent in a weight ratio of 1: 5-15, preferably 1: 10-13, and a conductive material having an aspect ratio of less than 10 is used. In this case, a large amount must be used for conductivity, and the adhesion is reduced accordingly, and the conductive material is not dispersed, which can cause the conductive materials to tangle with each other and agglomeration. this may be lowered.

In addition, when the content of the organic solvent based on the conductive material is less than the lower limit, the dispersion of the conductive material is lowered, so that the conductive materials are entangled with each other during application and agglomeration may occur. can be

Since the conductive material of the present invention uses an aspect ratio of 10 to 100, desired conductivity and paint adhesion can be achieved even when used in a small amount of 5 to 15 parts by weight, preferably 8 to 12 parts by weight, based on 100 parts by weight of the top coating composition. have. Even if a conductive material having an aspect ratio of 10 to 100 is used, unlike the present invention, when a conductive material is added to the top coating composition, it must be used in a high content of 20 parts by weight or more for desired conductivity, thereby improving the viscosity. It is not sprayed and the coating thickness is not even, and agglomeration may occur.

The conductive mixture is prepared by mixing a conductive material and an organic solvent and then dispersing it with an ultrasonic disperser, and pulses the mixture solution of the conductive material and organic solvent at a frequency of 15 to 25 kHz at 23 to 27 ° C for 5 to 10 seconds. , but rested for 1 to 5 seconds, and ultrasonically dispersed for 60 to 120 minutes under the condition of an amplitude of 20 to 40%. When the frequency and amplitude conditions during ultrasonic dispersion are out of the above ranges, the conductive material is not dispersed and agglomeration may occur in some parts when applied to the top coating composition. may be lowered.

While curing the top coating composition at 60 to 80 ° C., the conductive mixture is applied at 40 to 70% curing, and then cured at 60 to 80 ° C. for 4 to 8 hours to the upper side of the top coating composition (the side on which the conductive mixture is applied) The top coating composition and the conductive mixture are mixed to form a coating film in which the conductive material is dispersed on the top of the top coating composition.

The conductive material is not particularly limited as long as it has an aspect ratio of 10 to 100, but preferably includes at least one selected from the group consisting of carbon nanotubes, graphene, and milled carbon fibers.

In addition, the organic solvent is not particularly limited as long as it is a material that can be easily volatilized during curing, but preferably at least one selected from the group consisting of acetone, ether, ethanol and methanol.

That is, in the present invention, a conductive mixture is applied before the top coating composition is cured, and a conductive mixture in which a conductive material and an organic solvent are mixed, not a conductive material, is used, so that a conductive material having a high aspect ratio is used for high electrical conductivity. It has high adhesion and no agglomeration of conductive materials and no nozzle clogging.

In addition, the present invention can form a conductive coating film prepared according to the method for forming a conductive coating film according to the above method.

For example, the present invention may provide a conductive paint coating film comprising a top coating layer on the upper surface of a substrate and a conductive coating film provided on the top surface of the top coating layer. At this time, the conductive coating film is a layer in which the top coating composition (one side to which the conductive mixture is applied) and the conductive mixture are mixed.

As another example, the present invention can provide a conductive paint coating film comprising a primer layer on the upper surface of the substrate, a top coating layer provided on the top surface of the primer layer, and a conductive coating film provided on the top surface of the top coating layer, as shown in FIG. 2 . Again, the conductive coating film is a layer in which the top coating composition (one side to which the conductive mixture is applied) and the conductive mixture are mixed.

Hereinafter, preferred examples are presented to aid the understanding of the present invention, but the following examples are merely illustrative of the present invention and it will be apparent to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present invention, It goes without saying that such variations and modifications fall within the scope of the appended claims.

Example 1.

conductive mixture

Carbon nanotubes (aspect ratio 80) and acetone are mixed in a weight ratio of 1:10, pulsed for 10 seconds at a frequency of 20 kHz at room temperature with an ultrasonic disperser, paused for 5 seconds, and ultrasonicated for 90 minutes under the condition of 25% amplitude. A conductive mixture was prepared by dispersing.

conductive paint film

After applying a conventional primer composition to a substrate and curing it in a drying oven at 70° C. for 6 hours, a conventional top coating composition is applied to the upper surface of the primer layer and cured in a drying oven at 70° C. for 3 hours to obtain the top coating composition about Upon curing 50%, the conductive mixture was applied and cured in a drying oven at 70° C. for 6 hours to obtain a conductive paint film. At this time, the carbon nanotube was used in an amount of 8 parts by weight based on 100 parts by weight of the top coating composition.

Example 2. Use of milled carbon fiber

A conductive paint film was obtained in the same manner as in Example 1, except that milled carbon fibers were used instead of carbon nanotubes. At this time, the milled carbon fiber was used in an amount of 15 parts by weight based on 100 parts by weight of the top coating composition for conductivity.

Comparative Example 1. Addition of a conductive material in the top coating composition

20 parts by weight of carbon nanotubes were added (for conductivity) to 100 parts by weight of the conventional top coating composition and mixed to prepare a top coating composition containing the carbon nanotubes.

After applying a conventional primer composition to a substrate and curing it in a drying oven at 70° C. for 6 hours, the top coating composition containing the carbon nanotubes is applied to the upper surface of the primer layer and cured in a drying oven at 70° C. for 6 hours. A conductive paint film was obtained.

Comparative Example 2. Using a spherical conductive filler

A conductive paint film was obtained in the same manner as in Example 1, except that spherical carbon black, which is a spherical conductive filler, was used instead of carbon nanotubes. At this time, the spherical conductive filler was used in an amount of 50 parts by weight based on 100 parts by weight of the top coating composition for conductivity.

Comparative Example 3. Omission of the top coating composition

It was carried out in the same manner as in Example 1, except that the conductive mixture was directly applied without applying the top coating composition to the primer layer to obtain a conductive paint film.

Comparative Example 4. Application of conductive mixture after curing of the top coating composition

The same procedure as in Example 1, except that a conventional top coating composition was applied to the upper surface of the primer layer and cured for 6 hours in a drying oven at 70 ° C. and cured for 6 hours to obtain a conductive paint film.

<Test Example>

As a control, a top coating layer obtained by curing a general top coating composition was used.

Test Example 1. Measurement of coating adhesion

The conductive paint films prepared according to Examples and Comparative Examples were tested according to ASTM D4541 to measure pull-off strength.

division control Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 adhesion
(MPa) 1.04 0.96 0.84 0.23 0.31 0.48 0.03

As shown in Table 1 above, the conductive paint films prepared according to Examples 1 and 2 of the present invention showed similar or slightly lower paint adhesion to the control group, and had superior paint adhesion compared to the conductive paint films of Comparative Examples 1 to 4 confirmed that.

It was confirmed that the conductive paint film of Example 1 showed similar paint adhesion to the control.

On the other hand, in Comparative Example 4, it was confirmed that the conductive material was almost eliminated.

Test Example 2. Electrical Conductivity Measurement

As shown in FIG. 3, the electrical conductivity of the conductive paint films prepared according to the Examples and Comparative Examples was divided into 16 sections of 4 X 4 cm and the surface electrical resistance for each section was measured using the 4 probe method. analyzed.

Electrical Conductivity (M) Example 1 Example 2 Comparative Example 1

Comparative Example 2 Comparative Example 3 Comparative Example 4

-

In Comparative Example 4, the surface resistance was not measured because the conductive material was removed and hardly remained.

As shown in Table 2 above, it was confirmed that the conductive paint coating films prepared according to Examples 1 and 2 of the present invention had a low resistance and uniformly distributed surface resistance compared to the conductive paint coating films of Comparative Examples 1 to 4.

On the other hand, it was confirmed that the conductive paint coating films of Comparative Examples 1 to 4 had many sections in which electrical resistance was not properly measured, and showed very high electrical resistance even when the electrical resistance was measured.

Test Example 3. Surface Roughness Measurement

It is a photograph taken by SEM of the surface of the conductive paint coating film prepared according to Example 1 and Comparative Example 1.

Example 1 Comparative Example 1

As shown in Table 3 above, it was confirmed that the conductive paint coating film prepared according to Example 1 of the present invention had a lower surface roughness than the conductive paint coating film of Comparative Example 1.

In addition, as in Comparative Example 1, when carbon nanotubes are added to the top coating composition and used, the viscosity increases and spraying is not performed properly, so that the thickness of the painted surface is different for each section. It was confirmed that the dispersion degree of the nanotubes was lowered and the nozzle clogging phenomenon occurred.

However, as in Example 1 of the present invention, when the conductive mixture was applied and cured before the top coating composition was cured, it was confirmed that the carbon nanotubes were evenly dispersed on the surface and there was no nozzle clogging.

Test Example 4. Measurement of Adhesion

The adhesion of the conductive paint film was measured based on the ASTM D3359 cross-cut test. A cross cutter was used to cut the paint film in the 0° and 90° directions at intervals of 2 mm. After cleaning the cut side, a cross-cut test tape was attached to the cut side, and the tape was removed within 90 seconds in a 180° angle direction and the surface was observed.

Example 1 Comparative Example 1

As shown in Table 4 above, the conductive paint film prepared according to Example 1 of the present invention was measured as 5B and the conductive paint film of Comparative Example 1 was measured as 4B. Therefore, the conductive paint film prepared according to Example 1 was measured as Comparative Example It was confirmed that the adhesion was superior to that of 1.

Claims (13)

(A) applying a top coating composition to the substrate; and
(B) applying a conductive mixture solution when the top coating composition is cured by 40 to 70%; including,
The conductive mixture is a mixture of a conductive material having an aspect ratio of 10 to 100 and an organic solvent in a weight ratio of 1: 5-15,
The method of forming a conductive paint film, characterized in that the conductive material is used in an amount of 5 to 15 parts by weight based on 100 parts by weight of the top coating composition. The method of claim 1, further comprising the step of forming a primer layer by applying a primer composition to the substrate before applying the top coating composition in step (A). The method of claim 2, wherein the primer composition is cured at 60 to 80° C. for 4 to 8 hours. The method according to claim 1, wherein in step (B), the conductive mixture is applied at 40 to 70% curing while curing the top coating composition at 60 to 80°C. delete delete delete The method of claim 1, wherein the conductive material and the organic solvent are mixed for 60 to 120 minutes using an ultrasonic disperser. The method of claim 8, wherein the ultrasonic dispersion is given a pulse for 5 to 10 seconds at a frequency of 15 to 25 kHz at 23 to 27 °C, resting for 1 to 5 seconds, 60 to 120 under the condition of an amplitude of 20 to 40% A method of forming a conductive paint film, characterized in that ultrasonic dispersion is performed for minutes. The method of claim 1 , wherein the conductive material is at least one selected from the group consisting of carbon nanotubes, graphene, and milled carbon fibers. The method of claim 1, wherein the organic solvent is at least one selected from the group consisting of acetone, ether, ethanol and methanol. The method of claim 1, wherein after applying the conductive mixture in step (B), curing is performed at 60 to 80° C. for 4 to 8 hours. A conductive paint film prepared according to the method for forming the conductive paint film according to any one of claims 1 to 4 and 8 to 12.

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