TWI540191B - Electromagnetic wave shielding coating - Google Patents

Description

Electromagnetic wave shielding coating

The invention relates to a coating, in particular to an electromagnetic wave shielding coating.

In modern people's daily life, they will be exposed to many electronic products, such as TVs, mobile phones, and microwave ovens. These electronic products emit electromagnetic waves when they are used. These electromagnetic waves may cause harm to the human body. Therefore, many anti-electromagnetic products are used. It was born in response.

A material for shielding electromagnetic waves, such as a composite material having electromagnetic wave shielding effect and a preparation method thereof, which comprises a multi-walled carbon nanotube and a polyacrylonitrile. And one toluene, the multi-walled carbon nanotube has a mass ratio of 0.5 to 9 parts, the polyacrylonitrile has a mass ratio of 96 to 99.5 parts, and the toluene has a mass ratio of 15 to 30 parts, and the foregoing three components are mixed. And after coating 21 layers, it can shield high frequency electromagnetic waves.

However, such a composite material for electromagnetic wave shielding simply uses a multi-walled carbon nanotube as a conductive material, which has limited conductivity and poor electromagnetic shielding effect. Therefore, how to improve the ability of materials to shield electromagnetic waves is a common goal of the industry.

The main object of the present invention is to solve the problem that the conventional electromagnetic wave shielding material is not effective.

To achieve the above object, the present invention provides an electromagnetic wave shielding coating comprising a first dispersion liquid, a first wet conductive material, and a first organic slurry. The first dispersion liquid comprises a nano carbon material, an intervening active agent and an N-methylpyrrolidone solvent, and the nano carbon material accounts for 0.1% to 10% by weight of the first dispersion liquid. The weight percentage of the surfactant in the first dispersion is between 0.01% and 10%, and the weight percentage of the N-methylpyrrolidone solvent in the first dispersion is between 80%. Between % and 99%, the first wet conductive material comprises a silver-coated copper powder having a sheet-like structure and a wetting agent, the silver-coated copper powder having a particle diameter of between 10 μm and 90 μm, and The first wetted conductive material accounts for between 65% and 99% by weight, and the wetting agent accounts for between 1% and 35% by weight of the first wet conductive material. The first organic slurry comprises a polyester resin, a hardener and monoethyl cellulose, and the polyester resin accounts for between 80% and 90% by weight of the first organic slurry, the hardener The weight percentage of the first organic slurry is between 5% and 10%, and the ethyl cellulose accounts for the first organic slurry. Weight percentage between 1-10%.

Wherein, the first dispersion liquid accounts for between 60% and 90% by weight, and the first wetted conductive material accounts for between 5% and 25% by weight, the first organic slurry The weight percentage is between 5% and 20%.

To achieve the above object, the present invention further provides an electromagnetic wave shielding coating comprising a second dispersion and a second organic slurry. The second dispersion comprises an acidified nanocarbon material and an N-methylpyrrolidone solvent, and the acidified nanocarbon material accounts for between 0.1% and 10% by weight of the second dispersion. The N-methylpyrrolidone solvent accounts for between 80% and 99% by weight of the second dispersion, and the second wet conductive material comprises a silver-coated copper powder having a sheet structure and a moist The wet agent, the silver-coated copper powder has a particle diameter of between 10 μm and 90 μm, and the second wet conductive material accounts for between 65% and 99% by weight, and the wetting agent is in the first The weight percentage of the two wet conductive materials is between 1% and 35%, and the second has The machine slurry comprises a polyester resin, a hardener and monoethyl cellulose, and the weight percentage of the polyester resin in the second organic slurry is between 80% and 90%, and the hardener is used in the The second organic slurry accounts for between 5% and 10% by weight, and the ethylcellulose accounts for between 1% and 10% by weight of the second organic slurry.

Wherein, the second dispersion accounts for between 60% and 90% by weight, and the second wet conductive material accounts for between 5% and 25% by weight, the second organic slurry The weight percentage is between 5% and 20%.

As apparent from the above, in the present invention, by mixing the nanocarbon material and the silver-coated copper powder, the contact resistance between the nanocarbon materials can be lowered, and the absorption efficiency and shielding efficiency against electromagnetic waves can be improved.

S1~S4‧‧‧ steps

P1~P5‧‧‧ steps

FIG. 1 is a schematic flow chart showing the steps of a first embodiment of the present invention.

Figure 2 is a test data of the first embodiment of the present invention.

FIG. 3 is a schematic flow chart showing the steps of the second embodiment of the present invention.

The detailed description and the technical content of the present invention are described below with reference to the following drawings: The present invention provides an electromagnetic wave shielding coating. In the first embodiment, the electromagnetic wave shielding coating comprises a first dispersion liquid and a first wet conductive layer. And a first organic slurry. The first dispersion liquid comprises a nano carbon material, a surfactant and an N-methylpyrrolidone solvent, and the nano carbon material is selected from the group consisting of a carbon nanotube, a graphite thinner and a nanobelt, and The weight percentage in the first dispersion is between 0.1% and 10%; the surfactant is selected from the group consisting of carboxymethylcellulose ammonium and sodium carboxymethylcellulose, Occupy in a dispersion The weight percentage is between 0.01% and 10%; the weight percentage of the N-methylpyrrolidone solvent in the first dispersion is between 80% and 99%.

The first wet conductive material comprises a silver-coated copper powder and a wetting agent. In the present invention, the first wet conductive material refers to the silver-coated copper powder coated with the wetting agent, and the silver The copper-clad powder is coated with a layer of metallic silver on the surface of the copper powder, which can improve the conductivity and oxidation resistance of the copper powder, and the electromagnetic wave absorption can be increased by the presence of the silver-copper interface. In this embodiment, the silver-coated copper powder has a one-piece structure and a particle diameter of between 10 μm and 90 μm. When the silver-coated copper powder having a larger size is used, the silver-coated copper package is smaller in size. The copper powder will have the advantages of low cost, low usage amount and less contact surface, and the sheet structure can improve the film strength and contribute to the occurrence of multiple reflections to increase the absorption rate of electromagnetic waves, and the silver-coated copper powder The weight percentage of the first wet conductive material is between 65% and 99%, and the silver-coated copper powder can be more effectively dissolved in the first organic slurry by adding the wetting agent. The wetting agent is selected from the group consisting of n-octadecyl alcohol, n-hexadecanol and terpineol, and the weight percentage of the first wet conductive material is between 1% and 35%. .

The first organic slurry comprises a polyester resin, a hardener, and monoethyl cellulose. The hardener is selected from the group consisting of isocyanate and melamine, and the weight percentage in the first organic slurry is between 5% and 10%; the polyester resin is in the first organic slurry The percentage by weight is between 80% and 90%; the weight percentage of the ethyl cellulose in the first organic slurry is between 1% and 10%, and the ethyl cellulose can be The first organic slurry is adjusted to an appropriate viscosity to form a thicker coating for better efficacy, and the addition of the ethyl cellulose allows the invention to be attached to a plurality of inorganic substrates and organic substrates. .

In addition, referring to FIG. 1 , the manufacturing method of the first embodiment of the present invention includes the following steps:

S1: mixing a nano carbon material, a surfactant, and a N-methylpyrrolidone solvent, the intercalating agent makes the nano carbon material more easily dispersed in the N-methylpyrrolidone solvent In the middle, a first dispersion is formed, and by sufficiently dispersing the nanocarbon material, the efficiency of electromagnetic wave absorption and shielding can be improved.

S2: mixing a silver-coated copper powder with a wetting agent to form a first wet conductive material.

S3: mixing a polyester resin, a hardener, and monoethyl cellulose to form a first organic slurry.

S4: mixing the first dispersion liquid, the first wet conductive material, and the first organic slurry to form an electromagnetic wave shielding coating.

Referring to FIG. 2, the electromagnetic wave shielding coating of the first embodiment of the present invention is applied to a polyethylene terephthalate (PET) substrate according to the test data of the first embodiment of the present invention. The test was carried out and the coating thickness was 220 μm. Among them, the shielding efficiency is implemented according to ASTM D4935-99 test specification. It can be seen from Fig. 2 that when the shielding frequency of the invention is 30MHz to 1500MHz, the absorption rate can reach over 90%, and the shielding efficiency can reach 99.999%. Therefore, the electromagnetic wave shielding coating obtained in accordance with the first embodiment of the present invention has excellent shielding and absorption efficiency. Further, when electromagnetic waves are incident on the electromagnetic wave shielding coating, absorption, diffraction, reflection and absorption are generated at the interface between the nanocarbon material and the silver-coated copper powder, and the electromagnetic wave shielding coating is emitted again. Wherein, the silver-clad copper and the nano-carbon material help to increase the absorption rate instead of simply reflecting electromagnetic waves.

In a second embodiment of the present invention, the electromagnetic wave shielding coating comprises a second dispersion liquid, a second wet conductive material and a second organic slurry, and the efficacy of the same material and the first implementation are specifically described. For the same example, please refer to the previous paragraph, which will not be repeated here. The second dispersion comprises an acidified nanocarbon material and an N-methylpyrrolidone solvent, wherein the acidified nanocarbon material is selected from the group consisting of a carbon nanotube, a graphite thinner and a nanobelt, and The weight percentage in the second dispersion is between 0.1% and 10%; the weight percentage of the N-methylpyrrolidone solvent in the second dispersion is between 80% and 99%.

The second wetted conductive material comprises a silver-coated copper powder and a wetting agent. In the embodiment, the silver-coated copper powder is also a piece-like structure, and the particle diameter is between 10 μm and 90 μm. The silver-coated copper powder accounts for between 65% and 99% by weight of the second wet conductive material, and the wetting agent is selected from the group consisting of n-octadecanol, n-hexadecanol and terpineol. The group, and the weight percentage of the second wet conductive material is between 1% and 35%.

The second organic slurry comprises a polyester resin, a hardener, and monoethyl cellulose. The hardener is selected from the group consisting of isocyanate and melamine, and the weight percentage in the second organic slurry is between 5% and 10%; the polyester resin is in the second organic slurry The percentage by weight is between 80% and 90%; the weight percentage of the ethyl cellulose in the second organic slurry is between 1% and 10%.

Referring to FIG. 3, the manufacturing method of the second embodiment of the present invention includes the following steps:

P1: A nano-carbon material is subjected to an acidification process to form an acidified nanocarbon material.

P2: mixing the acidified nanocarbon material and a N-methylpyrrolidone solvent to sufficiently disperse the nanocarbon material to form a second dispersion.

P3: mixing a silver-coated copper powder with a wetting agent to form a second wet conductive material.

P4: A polyester resin, a hardener, and monoethyl cellulose are mixed to form a second organic slurry.

P5: mixing the second dispersion, the second wet conductive material, and the second organic slurry to form an electromagnetic wave shielding coating.

In summary, the present invention has the following features:

First, the efficiency of electromagnetic wave absorption and shielding can be improved by first dispersing the nano carbon material.

Second, the absorption of electromagnetic waves can be increased by the silver-copper interface of the silver-coated copper powder.

Third, the sheet structure can increase the strength of the film and contribute to the occurrence of multiple reflections to increase the absorption rate of electromagnetic waves.

4. The silver-coated copper powder having a larger particle size has advantages such as cost advantage, small amount of use, and less contact surface than the silver-coated copper powder having a smaller particle size.

5. The organic slurry can be adjusted to an appropriate viscosity by adding the ethyl cellulose to form a thick coating layer, and the present invention can be attached to a plurality of inorganic substrates and organic substrates.

6. By mixing the nanocarbon material and the silver-coated copper powder, electromagnetic wave absorption efficiency and shielding efficiency can be improved.

7. The silver-clad copper and the nano-carbon material help to increase the absorption rate, instead of simply reflecting electromagnetic waves, and therefore can also be applied to the case where the electronic component must be completely covered without causing the component to be disturbed by reflected electromagnetic waves.

The present invention has been described in detail above, but the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the scope of the invention. That is, the equivalent changes and modifications made by the scope of the present application should remain within the scope of the patent of the present invention.

S1~S4‧‧‧ steps

Claims (6)

An electromagnetic wave shielding coating comprising: a first dispersion comprising a nano carbon material, a surfactant, and an N-methylpyrrolidone solvent, wherein the nano carbon material is occupied by the first dispersion The weight percentage is between 0.1% and 10%, the weight percentage of the surfactant in the first dispersion is between 0.01% and 10%, and the N-methylpyrrolidone solvent is in the first The weight percentage of the dispersion is between 80% and 99%; a first wet conductive material comprising a silver-coated copper powder having a sheet-like structure and a wetting agent, the silver-coated copper powder The particle size is between 10 μm and 90 μm, and the weight percentage of the first wet conductive material is between 65% and 99%, and the weight of the wetting agent on the first wet conductive material a percentage between 1% and 35%; and a first organic slurry comprising a polyester resin, a hardener, and monoethyl cellulose, the weight of the polyester resin in the first organic slurry The percentage is between 80% and 90%, and the weight percentage of the hardener in the first organic slurry is Between 5% and 10%, the weight percentage of the ethyl cellulose in the first organic slurry is between 1% and 10%; wherein the weight percentage of the first dispersion is between Between 60% and 90%, the first wet conductive material accounts for between 5% and 25% by weight, and the first organic slurry accounts for between 5% and 20% by weight. . The electromagnetic wave shielding coating according to claim 1, wherein the wetting agent is selected from the group consisting of n-octadecanol, n-hexadecanol and terpineol. The electromagnetic wave shielding coating according to claim 1, wherein the nano carbon material is selected from the group consisting of a carbon nanotube, a graphite thinner and a nanobelt. An electromagnetic wave shielding coating comprising the following components: a second dispersion comprising an acidified nanocarbon material and an N-methylpyrrolidone solvent, wherein the acidified nanocarbon material accounts for between 0.1% and 10% by weight of the second dispersion. The N-methylpyrrolidone solvent accounts for between 80% and 99% by weight of the second dispersion; a second wet conductive material comprising a silver-coated copper powder having a sheet-like structure and a wetting agent, the silver-coated copper powder has a particle diameter of between 10 μm and 90 μm, and the weight percentage of the second wet conductive material is between 65% and 99%, and the wetting agent is The second wet conductive material accounts for between 1% and 35% by weight; a second organic slurry comprises a polyester resin, a hardener and monoethyl cellulose, and the polyester resin The second organic slurry accounts for between 80% and 90% by weight, and the hardener accounts for between 5% and 10% by weight of the second organic slurry. The percentage by weight of the second organic slurry is between 1% and 10%; wherein the weight percentage of the second dispersion Between 60% and 90%, the second wet conductive material accounts for between 5% and 25% by weight, and the second organic slurry accounts for 5% to 20% by weight. between. The electromagnetic wave shielding coating according to claim 4, wherein the wetting agent is selected from the group consisting of n-octadecanol, n-hexadecanol and terpineol. The electromagnetic wave shielding coating according to claim 4, wherein the acidified nano carbon material is selected from the group consisting of a carbon nanotube, a graphite thinner and a nanobelt.