KR101938341B1 - Lacquer Paint Composition for Shielding Electromagnetic Waves and the Fabrication Method Thereof - Google Patents

Abstract

TECHNICAL FIELD The present invention relates to a conductive lacquer coating composition having excellent electromagnetic wave shielding ability. Specifically, the lacquer coating composition according to the present invention contains lacquer, a conductive carbon material of one- or two-dimensional nanostructure, and metal particles.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lacquer coating composition for electromagnetic shielding,

TECHNICAL FIELD The present invention relates to a coating composition for electromagnetic shielding, and more particularly, to a conductive coating composition for shielding electromagnetic waves based on natural bio-materials having excellent electromagnetic wave shielding ability, flame retardancy, insect repellency, antibacterial, heat resistance and waterproofing properties.

The lacquer trees are present in East Asia, North America and Central America since the third Cenozoic era, and have existed since about 70 million years ago.

Rhus verniciflua stokes native to Korea, Japan and China, Rhus succedanea Linnaeus var. Damoutieri kudo et Matsumra from Vietnam and Thailand, northern mountainous region of Myanmar And Gluta usitata, which grows in the northern part of Thailand and India, and Gluta laccifera, Cambodia.

Natural lacquer varies depending on species and climate. The lacquer which is collected from the Japanese lacquer tree which is native to Korea, China and Japan is mainly composed of urushiol, and the lacquer collected from the Rhus succedanea Linnaeus var. Demoutieri kudo et Matsumra of Vietnam, Thailand, Laccol) is known as the main component. The lacquer collected from the Myanmarus lacquer (Melanorrhoea usitata), which grows in the northern mountainous region of Myanmar, the northern part of Thailand, and India, is known to be mainly composed of Thitsiol.

When natural lacquer is scratched by a lacquer tree, the tree secretes milky white liquid to heal the wound, and it is lighter to take it. The fresh chestnut collected from the common tree is composed of 50 to 80% by weight of catechol, 5 to 35% by weight of glycoprotein and carbohydrate, 1 to 2% by weight of laccase and 10 to 30% by weight of water .

Natural lacquer has the characteristics of antimicrobial, fungic, heat resistance, insolubility, water resistance, removal of volatile organic compounds (VOCs), humidity control, spontaneity, abrasion resistance, solvent resistance and acid / It has been recognized for its excellence as a natural coating material.

On the other hand, modern society, which is a turning point to a highly information-oriented society, has been increasing the use of electric, electronic, and information devices in a wide range of fields, along with the development of electronic technology, The electromagnetic waves generated in the environment disturb the ecosystem and have serious effects on the human body.

Electromagnetic waves are divided into high frequency waves emitted from mobile phones, radar, TV, microwave oven, etc., and low frequency waves emitted from electric appliances, transmission lines, substations, etc. Commonly known social problems of electromagnetic wave interference include health problems, electromagnetic wave malfunctions, .

Currently, there is a method of protecting the external equipment by shielding the vicinity of the electromagnetic wave generating source in order to prevent the electromagnetic wave disturbance, and a method of protecting the equipment inside the shielding material and protecting it from the external electromagnetic wave generating source. The most popular method for this purpose is the electromagnetic shielding material.

Examples of the electromagnetic wave absorbing material include a conductive electromagnetic wave absorbing material, a dielectric wave absorbing material, and a magnetic electromagnetic wave absorbing material. Conductive materials are materials that absorb radio waves by currents flowing through resistors, resistive wires, and resistive coatings. It is important to select materials with appropriate resistance values when they are used, and it is also possible to obtain excellent electromagnetic wave absorbers by using fabrics made of conductive fibers have. As an electromagnetic wave shielding material, it is widely known that a metal material shields electromagnetic waves. When an electromagnetic wave comes into contact with an electric conductor, some of the electromagnetic wave is absorbed and passed, but is mostly reflected from the surface. This is because if an electromagnetic wave touches the conductor, an eddy current is generated in the conductor by the electromagnetic induction, and this reflects the electromagnetic wave. On the other hand, the magnetic field leaks even when the magnet is wrapped with an aluminum plate, but the magnetic field is shielded when it is wrapped with a steel plate. Therefore, it is effective to shield the electromagnetic wave shield by wrapping it with a material having a high conductivity such as aluminum and a high dielectric constant such as an iron plate. The plastic used as the housing of the electronic device is an insulator and the electromagnetic waves escape. Thus, the electromagnetic wave shielding can be achieved by surface-treating the housing with a conductor such as a metal such as electroless plating.

In recent years, due to the trend toward miniaturization and light weight, low price due to mass production, and ease of design, computers, mobile phones and most electronic products use plastic as a housing material. However, plastic is not suitable as an electromagnetic shielding material because it is an electric insulator. Therefore, four methods of electroless plating, vacuum deposition, conductive coating (spray) and incorporating a conductive material into plastic are mainly used.

A conductive paint used for a conductive coating for shielding electromagnetic waves is prepared by adding metal powder to a water-dispersible acrylic resin or a urethane resin (Korean Patent Registration No. 10-0624316, 10-0455338, 10-0455338, 10- 0529775, 10-0671000, 10-0752748, 10-1049955) or by adding a carbon nanomaterial and a metal powder (Korean Patent Registration No. 10-0638393). However, in the case of a conductive coating composition based on a carbon nanomaterial, the dispersibility of carbon nanotubes is very low, and there are problems to be solved in terms of shielding performance, applicability, and cost of electromagnetic shielding materials, which is a hindrance to commercialization.

Korean Patent No. 10-0624316, Korean Patent No. 10-0642468, Korean Patent No. 10-0455338, Korean Patent No. 10-0529775, Korean Patent No. 10-0671000, Korean Patent No. 10-0752748, Korean Patent No. 10-1049955, Korean Patent No. 10-0638393

It is an object of the present invention to provide a conductive coating composition based on a natural bio-material having excellent electromagnetic shielding ability, flame retardant, insect repellent, antibacterial, heat resistance and waterproof properties.

It is another object of the present invention to provide a non-aqueous conductive coating composition based on a conductive carbon material having a nanostructure such as carbon nanotubes or graphene.

Another object of the present invention is to provide a method for manufacturing a carbon nanotube which is based on a conductive carbon material having a nano structure such as a natural bio material and a carbon nanotube or a graphene and which does not need a separate pretreatment for improving the dispersibility of the carbon nanotube, The present invention is to provide a conductive paint composition which can have excellent electromagnetic wave shielding ability by the as-fabricated conductive carbon material.

It is another object of the present invention to provide a method of producing a carbon nanotube having excellent electromagnetic wave shielding ability based on a nanomaterial conductive carbon material such as natural biomaterial and carbon nanotube or graphene by an extremely simple and mass- , Flame retardant, insect repellent, antibacterial, heat-resistant and waterproof.

The conductive lacquer coating composition according to the present invention contains lacquer, a conductive carbon material of one- or two-dimensional nanostructure, and metal particles.

In the lacquer coating composition according to an embodiment of the present invention, lacquer may be refined lacquer.

The lacquer coating composition according to one embodiment of the present invention may contain 1 to 10 parts by weight of conductive carbonaceous material and 100 to 300 parts by weight of metal particles based on 100 parts by weight of lacquer.

The lacquer coating composition according to an embodiment of the present invention may further include a non-aqueous solvent and an additive including a dispersing agent.

The lacquer coating composition according to an embodiment of the present invention may contain 1 to 20 parts by weight of a dispersing agent based on 100 to 500 parts by weight of non-aqueous solvent and 100 parts by weight of non-aqueous solvent based on 100 parts by weight of lacquer.

In the lacquer coating composition according to an embodiment of the present invention, the metal particles may be spherical or flake-shaped.

In the lacquer coating composition according to one embodiment of the present invention, the metal particles may have a size distribution of Unimodal, Bimodal or Triimodal.

In the lacquer coating composition according to an embodiment of the present invention, the conductive carbon material may be a single wall carbon nanotube, a double wall carbon nanotube, a multi wall carbon nanotube, a thin multi wall carbon nanotube, a multiple carbon nanotube, One or more selected from reduced graphene oxide (RGO) may be selected.

In the lacquer coating composition according to one embodiment of the present invention, the metal particles include silver particles; Platinum particles; Core-shell particles having a shell of silver or platinum on the core of a dissimilar metal different from silver or platinum; Or mixed particles thereof.

The lacquer coating composition according to an embodiment of the present invention may be used for shielding electromagnetic waves.

A method for preparing a conductive lacquer coating composition according to the present invention comprises the steps of: a) mixing a lacquer with a conductive carbon material having a one- or two-dimensional nanostructure and metal particles to prepare a primary mixture; And b) mixing and stirring the primary mixture with an additive comprising a non-aqueous solvent and a dispersing agent.

The present invention includes a substrate including a coated film on which the above-described lacquer coating composition is applied and dried.

The conductive lacquer coating composition according to the present invention is advantageous as a coating composition based on a natural nano-bio material as a matrix material is lacquered, and has various properties known in conventional lacquer such as antibacterial, fungus, insect repellent, At the same time, has very good conductivity and can be effectively used for antistatic, electrostatic dissipation, conductive coating, and / or electromagnetic shielding applications.

Further, the conductive lacquer coating composition according to the present invention is based on lacquer, which is a natural nano-bio material, and has characteristics that carbon nanotubes, graphenes and metal powders are stably dispersed in lacquer, It is unnecessary to use an expensive and expensive reforming process such as critical treatment and it is advantageous to use carbon nanotubes or graphenes as they are.

In addition, the conductive lacquer coating film made of the conductive lacquer coating composition according to the present invention can be used as a clean room, an equipment / component for semiconductor manufacturing, a housing material, various military equipment, a shield room, a mobile phone case, It can be widely applied not only for industrial products such as anti-static inner coating but also for military use.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a measurement result of electromagnetic wave shielding efficiency of a coated film manufactured according to an embodiment of the present invention. FIG.

Hereinafter, the conductive lacquer coating composition of the present invention and its preparation method will be described in detail with reference to the accompanying drawings. The following drawings are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the following drawings, but may be embodied in other forms, and the following drawings may be exaggerated in order to clarify the spirit of the present invention. Hereinafter, the technical and scientific terms used herein will be understood by those skilled in the art without departing from the scope of the present invention. Descriptions of known functions and configurations that may be unnecessarily blurred are omitted.

Carbon Nano-Tubes, recently developed as a conductive material, is a state-of-the-art material, and has various advantages such as high strength and excellent heat / electric conductivity.

However, these carbon nanotubes are not only very agglomerated, but also have difficulty in commercial use due to the difficulty of dispersing carbon nanotubes that are excellent and stable due to strong π-π interaction.

Carbon nanotubes are small in diameter, but have a very large aspect ratio, which is a ratio of diameter to length. Therefore, the carbon nanotubes are bundled or intertwined in a bulk state. In order for these carbon nanotubes to exhibit their excellent properties, the network between the carbon nanotubes should be well dispersed in the substrate, and the low dispersibility of the carbon nanotubes must be solved.

For this purpose, studies have been made to modify the surface of carbon nanotubes or to improve the dispersibility of carbon nanotubes by using a surfactant or the like. As an example of the surface modification, a functional group (hydroxyl, carboxyl, carbon, and the like) is formed on the surface of the carbon nanotube by graft polymerization of a medium and a polymer affinity to the surface of the carbon nanotube, or acid treatment or supercritical , Amine, vinyl group, etc.), and the like. However, when a heterogeneous material (for example, a material-friendly polymer) is bonded to the surface of the carbon nanotube, the contact resistance is increased when the carbon nanotube network is formed, making it difficult to apply to a conductive coating composition. In addition, in the case of chemical modification of the surface of a carbon nanotube through an acid treatment or the like, it is difficult to construct and manage the process and it is required to be costly, and it is not suitable for mass production and a large amount of defects in the graphene molecular structure of the carbon nanotube Or deterioration of the quality of the carbon nanotubes can not be avoided. Surfactants and the like are used, it is possible to effectively minimize the strong interaction between the carbon nanotubes due to static electricity or steric hindrance caused by the surfactant adsorbed on the surface of the carbon nanotubes. However, such a surfactant has a risk of obstructing smooth film formation when the carbon nanotubes are mixed with a matrix of a different material, and deteriorates the physical properties of the carbon nanotube-based composite. Further, there is a limitation in that long-term dispersion stability (storage stability) can not be maintained due to adsorption of the surfactant, dynamic state of the desorption equilibrium, and strong attraction of the carbon nanotubes.

The applicant of the present invention conducted research on a natural material-based coating composition, and found that the lacquer has an off-white emulsion structure in the form of oil / water (o / w) For example, urushiol has been studied extensively for the complexation of lacquer with carbon nanotubes or graphene, noting that both hydrophilic groups and hydrophobic groups (hydrophilic groups) are present. As a result of this research, we found that conductive carbon materials such as carbon nanotubes and graphenes, which are in the state of manufacture, are remarkably excellent and stable dispersed in lacquer without any help of surface treatment or surfactant. And dispersed stably regardless of the shape thereof, and thus the present invention has been accomplished.

The conductive lacquer coating composition according to the present invention based on the above findings contains lacquer, conductive carbon material of one- or two-dimensional nanostructure, and metal particles.

The lacquer may include raw lacquer (fresh), refined lacquer or a mixture thereof. As is known, refined lacquer can be applied to all types of lacquer produced through raw lacquer separation, purification, processing and / It can mean.

The lacquer contained in the composition is not only a matrix material for forming a matrix of a coating film but also can act as a dispersing agent which can extremely effectively disperse conductive carbon materials such as carbon nanotubes and graphenes.

Well, lacquer can be refined lacquer. The refined lacquer may contain water (free of water) evaporated and removed as free water by refining process, and may contain (only) the number of bonds bound to micelles of oil / water (o / w) type. When lacquer is refined lacquer, carbon nanotubes are extremely fast and stable in a very short period of time by simple physical stirring even when lacquer is mixed with lacquer and severely tangled carbon nanotube bundles due to the micelle structure in which all the free water is removed. And it is advantageous that the extremely excellent dispersion state can be stably maintained for a long time and that the metal particles can be dispersed very uniformly and stably in the refined lacquer. Particularly, in the case of refined lacquer, non-spherical metal particles such as conductive carbon material including carbon nanotube or graphene and flake shape are kept in a very homogeneous and well dispersed state, so that a small amount of carbon material has very low sheet resistance A coating film can be formed and a coating film having uniform electrical characteristics can be formed, which is advantageous.

As described above, the lacquer contained in the composition may be a raw lacquer (fresh lacquer) collected from natural materials. However, in order to achieve better dispersibility and dispersion stability of conductive carbon materials and non-spherical metal particles, It is advantageous if the water content is reduced to 5% by weight or less of refined lacquer.

Thus, refined lacquer may be produced from raw lacquer as a raw material by conventional or recombinant method, and may mean lacquer containing not more than 5% by weight of water.

Specifically, the refined lacquer contains 60 to 90% by weight of catechol, a catechol derivative (e.g., urushiol) or a mixture thereof derived from fresh lacquer, and contains 5% by weight or less of water, And may be lacquer containing 5% by weight of water.

More specifically, for example, the refined lacquer may comprise 60 to 90% by weight of catechol, a catechol derivative (e.g., urushiol) or a mixture thereof resulting from fresh lacquer, 1 to 5% by weight of water, And lacquer containing 5 to 35% by weight of an organic solvent-insoluble compound. In this case, the organic solvent-insoluble compound may be glycoprotein, carbohydrate, gum, laccase, etc. However, it goes without saying that the specific material may vary depending on the kind of lacquer tree from which the green lacquer is obtained.

In terms of manufacturing method, refined lacquer may mean lacquer produced from natural lacquer in a conventional manner or in a recombinant manner. The fresh green can include all the lacquer collected from the lacquer tree on the earth. When a lacquer tree is wound, the tree releases milky white juice to heal the wound, and natural lacquer can mean juice taken. The traditional method of manufacturing is to use a traditional method to purify the freshness of the lacquer tree. The lacquer picked from the lacquer tree is sieved with a sieve (filter cloth), and the water is naturally evaporated while stirring at room temperature to give a water content of 3 to 5 wt% May mean a process for producing a transparent brown liquor (refined lacquer) in a contained state. Recombination method is a method of reclaiming a laccase which is a raw material including a lacquer which has been corroded or contaminated by contamination in the process of collection and distribution, It is a method to purify the raw fish. Concretely, the recombination method is a method of dissolving catechol dissolved in an organic solvent and the remaining insoluble components in an organic solvent by diluting the fresh (low-grade fresh green) with an organic solvent, and mixing the organic solvent insoluble components in a cool dark place And then, if necessary, it is dried within 24 hours. In addition, in the recombinant method, the fresh (low-grade fresh) is filtered with a filter cloth to filter out foreign substances, and then a 2 to 5-fold weight ratio of acetone, alcohol such as methanol, ethanol, isopropanol, n-propanol, , And the mixture is separated by filtration under reduced pressure or centrifugal separation. The catechol dissolved in the organic solvent layer is recovered by using a rotary evaporator to purify the catechol, and the insoluble compound in the organic solvent is naturally dried at room temperature And then stored in a refrigerator or dry cryocontainer. If necessary, an organic solvent-insoluble component and water may be added to the catechol in an arbitrary ratio and mixed again to prepare a refined lacquer of high quality.

The conductive carbon material of a one- or two-dimensional nanostructure may be a conductive carbon material having a one-dimensional nanostructure, a conductive carbon material having a two-dimensional nanostructure, or a mixture thereof. The conductive carbon material having a one-dimensional nanostructure may be a single-walled carbon nanotube, a double-walled carbon nanotube, a multi-walled carbon nanotube, a thin multi-walled carbon nanotube, a multi-walled carbon nanotube, a carbon fiber, or a mixture thereof. The conductive carbon material having a two-dimensional nanostructure may be graphene, reduced graphene oxide, or a mixture thereof.

The conductive carbon material having a one- or two-dimensional nanostructure can form a conductive network in a coating film obtained by applying and drying the coating composition. That is, a continuous current path can be formed at least in the plane direction of the coating film by a network of conductive carbon materials of one-dimensional nanostructure and / or two-dimensional nanostructure.

The one-dimensional nano-structure and / or the second conductive sheet a ratio of the reduced diameter compared to the major axis length of the conductive carbon material having a 1-dimensional nanostructures from the conductive network formed side by carbonaceous material reduced in dimension nanostructures ratio (aspect ratio) of 10 ² to 10 ⁶ , and the average diameter of the conductive carbon material having a two-dimensional nanostructure may be on the order of several tens nanometers to several hundreds of micrometers, specifically, 50 nm to 100 μm. However, the present invention is not limited thereto no.

As described above, since the conductive carbon material is mixed and dispersed in the refined lacquer, which is a fluid, the conductive carbon material of one-dimensional nanostructure and the conductive carbon material of two-dimensional nanostructure are separately surface modified May be as-fabricated without being performed.

Furthermore, in order to obtain an electromagnetic shielding effect excellent in coating film produced using the lacquer coating composition according to the present invention, it is advantageous to contain metal particles that reflect electromagnetic waves together with a conductive carbon material forming a conductive network.

As described above, in the composition according to the present invention, lacquer, advantageously, refined lacquer is a dispersion medium (main dispersion medium) of a conductive carbon material and a matrix-forming material of a coating film and a dispersant of metal particles and conductive carbon material. Accordingly, an irregularly dispersed conductive carbon material such as carbon nanotube or graphene can be stably dispersed in lacquer without the need for a separate surface modification or a dispersing agent such as a surfactant. In addition, when lacquer, advantageously, refined lacquer is a matrix-forming material of a coating material such as a dispersion medium (main dispersion medium), metal particles can be stably dispersed in lacquer without any special treatment or with the aid of a dispersant.

According to the key idea of the present invention, it should be noted that the present invention includes a stock liquid (raw material liquid) used as a raw material for producing a conductive lacquer coating composition. In detail, the raw material liquid according to the present invention includes lacquer, advantageously refined lacquer, conductive carbon material of one-dimensional nanostructure and / or two-dimensional nanostructure, and metal particles, but not containing a dispersant containing a surfactant have. More specifically, the lacquer is a coating film forming material, and as a dispersion medium and a dispersing agent, the raw material liquid can be composed of lacquer (advantageously refined lacquer), a conductive carbon material in a state immediately after preparation, and metal particles.

In one embodiment of the present invention, the metal of the metal particles may comprise an alkali metal, an alkaline earth metal, a transition metal, a post-transition metal, or an alloy thereof or a mixture thereof. However, from the viewpoint of ensuring more excellent electromagnetic wave shielding ability, the metal particles are silver particles; Platinum particles; Core-shell particles having a shell of silver or platinum on the core of a dissimilar metal different from silver or platinum; Or mixed particles thereof. In the case of particles of the core-shell structure, the core of dissimilar metals different from silver or platinum may be a metal selected from an alkali metal, an alkaline earth metal, a transition metal, and a pre-metal, and as a practical example of such a core material, Nickel, aluminum and the like which are easy to supply and supply raw materials and have excellent conductivity, but it is needless to say that the present invention can not be limited to the specific materials constituting the core.

The metal particles may be spherical particles, flake particles, or spherical and flake mixed particles, and advantageously flake-shaped particles. When the metal particles are in the form of flakes, it is advantageous that a larger amount of contact between the metal particles and the conductive network formed by the conductive carbon material can be obtained. In addition, when the metal particles are flake-shaped, since the metal particles can form a conductive network together with the conductive carbon material, a stable network can be formed, and a conductive network having a lower resistance can be formed. Further, when the metal particles are flake-shaped, a stable conductive network can be formed even if the content of the conductive carbonaceous material in the composition is reduced, so that the quality of the coating film (for example, a coating film having a smooth surface) It is advantageous to satisfy. Furthermore, when the metal particles are flake-shaped, it is advantageous that the area capable of absorbing and reflecting the electromagnetic wave incident on the coating film (the area ratio occupied by the metal in the plane direction of the coating film) increases.

In addition, when the average size of the metal particles is excessively large, even though the metal particles are in contact with each other, the space between the particles and the particles is too large and disadvantageous to electromagnetic wave shielding. Thus, it is advantageous that the metal particles are fine particles having an average size of 20 탆 or less, and in particular, it is advantageous to have an average size of 1 to 20 탆.

The metal particles may have a uniform Moon distribution, a bimodal distribution, or a tri-modal distribution in terms of particle size distribution, and may advantageously have a bimodal distribution (bimodal or tri-modal). In the case where the metal particles have a bimodal distribution having a relatively large size peak (first peak) and a relatively small size peak (second peak) in terms of their size distribution, Relatively fine metal particles belonging to the second peak may be located in the intergranular space of the metal particles. Accordingly, when a certain amount of light is incident on the coating film, a large amount of incident light is reflected by being in contact with the metal in the coating film, so that the electromagnetic wave shielding efficiency can be further improved. The center size of the first peak and the center size of the second peak may be 1 to 20 mu m and the size difference between the center size of the first peak and the center size of the second peak may be 3 mu m to 15 mu m. In this case, when the metal particles are flake-shaped, the average size (or the center size of the peak) may be an average size calculated in terms of a circle having the same area as the flake. The metal particles may be commercially available commercial metal powders having a desired size and shape. For example, commercially available powders include powders such as Degussa, Metalor, Mitsui, Ferro, , And ChangSung Co., Ltd., and the like, but the present invention is not limited thereto.

In one embodiment of the present invention, the composition may contain 1 to 10 parts by weight of a conductive carbonaceous material, based on 100 parts by weight of lacquer, and advantageously 100 parts by weight of refined lacquer. When the composition contains less than 1 part by weight of the conductive carbonaceous material relative to 100 parts by weight of the lacquer, the shielding effect is remarkably deteriorated due to the high surface resistance of the prepared coating film. When the composition contains more than 10 parts by weight of the conductive carbonaceous material, It is possible to exhibit a high shielding ratio, but the adhesion and the surface property of the coating film may deteriorate, resulting in difficulty in coating. Further, in terms of production of a coating having a smooth surface with a low surface resistance, the composition contains 1 to 7 parts by weight of conductive carbon material, advantageously 3.5 to 6 parts by weight of conductive carbon material, based on 100 parts by weight of lacquer .

In one embodiment of the present invention, the composition comprises 100 to 300 parts by weight of metal particles based on 100 parts by weight of lacquer, advantageously 100 parts by weight of refined lacquer, advantageously 150 to 200 parts by weight, 300 parts by weight of metal particles. When the composition contains less than 100 parts by weight of metal particles relative to 100 parts by weight of lacquer, there is a danger that the shielding efficiency is lowered due to too high surface resistance. When the composition contains more than 300 parts by weight of metal particles, The binding force and surface properties of the coating film may be poor due to the content.

As described above, lacquer, advantageously refined lacquer can disperse conductive carbon material and metal nanoparticles extremely effectively and stably without the aid of a dispersant or surface modification of the conductive carbon material. Thus, as described above, the stock liquid (raw material liquid) may not contain a separate dispersant including a surfactant to improve the dispersibility. However, in the case of a coating composition, it is necessary that the viscosity should be appropriately adjusted for the method according to the coating method, and the viscosity should be appropriately adjusted even for the spreadability of the coating composition, the uniformity of the coating film, and the aesthetic aspect such as a smooth coating film surface .

Since the composition according to the present invention is a lacquer-based composition, it is advantageous that the solvent added for viscosity control is a non-aqueous solvent in terms of compatibility with lacquer. However, when a non-aqueous solvent is added to the lacquer for viscosity control or the like, there is a risk that the dispersibility of the conductive carbon material stably dispersed in the stock solution (raw material liquid) may be impaired by the non-aqueous solvent. In view of maintaining the dispersibility of the conductive carbon material already well dispersed in lacquer, it is advantageous to add an additive including a dispersant together with a non-aqueous solvent when adding a non-aqueous solvent to the lacquer.

Thus, in one embodiment of the present invention, the lacquer coating composition may further include a non-aqueous solvent and an additive including a dispersing agent. The non-aqueous solvent may be an organic solvent (non-aqueous organic solvent) used as a viscosity control agent or a dispersion medium in a conventional non-aqueous coating composition, but minimizes the deterioration of dispersibility and, at the same time, , An organic solvent having unbonded electron pairs (lone pair electron) in molecules such as sulfur and / or phosphorus. As a specific example, the organic solvent which is a non-aqueous solvent is at least one selected from the group consisting of methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, ethylene glycol, butyl cellosolve, Carbitol and terfenafine, and the like, but the present invention is not limited thereto. The dispersant contained as an additive may be a compound usually used for improving the dispersibility of a solid phase component in a conventional coating composition. As a specific example, the dispersant may be at least one selected from surfactants and wet dispersants. As a more specific example, the surfactant may include one or more selected from a nonionic surfactant, a cationic surfactant, and an anionic surfactant, and the wetting and dispersing agent may be a chlorine compound, a fluorine compound, a silicon compound, Compounds, glycol-based derivatives, and the like. Dispersing agents may also be used as commercially available dispersing agents, such as DISPER BYK-180, 182, 184, 190 to 194 and 9076 of BYK Co., but the present invention is not limited thereto.

As described above, since the dispersant contained as the additive is required by the non-aqueous solvent, the content of the dispersant varies depending on the content of the non-aqueous solvent in the composition, not the content of the conductive carbon material or the metal particles. It should be noted.

In detail, the composition may contain a non-aqueous solvent to have a proper viscosity in consideration of the specific application method (coating method or coating method) and the coating film, but considering the practically applicable application method, And advantageously from 100 to 500 parts by weight of non-aqueous solvent based on 100 parts by weight of refined lacquer. At this time, in the case of an organic solvent having unpaired electron pair (lone pair electron) in the molecule such as nitrogen, oxygen, sulfur and / or phosphorus, the amount of organic solvent used can be minimized by excellent miscibility. Specifically, when the non-aqueous solvent is an organic solvent having an unbonded electron pair, the composition may contain 100 to 350 parts by weight of the non-aqueous solvent based on 100 parts by weight of the purified lacquer. The dispersant contained in the composition together with the nonaqueous solvent is preferably contained in an amount of 1 to 20 parts by weight, more preferably 1 to 6 parts by weight, based on 100 parts by weight of the nonaqueous solvent, in order to effectively prevent the deterioration of the dispersibility by the non- It is advantageous to be contained in the composition by weight. That is, when the composition according to an embodiment of the present invention further contains a non-aqueous solvent, the composition may further include an additive including a dispersant in combination with a non-aqueous solvent, 500 parts by weight of a non-aqueous solvent, and the composition may contain from 1 to 20 parts by weight of a dispersant based on 100 parts by weight of the non-aqueous solvent. Furthermore, it is advantageous that the total solid components (lacquer, conductive carbon material and metal particles which are converted into solid in the coating film) included in the composition fall within the range of 40 to 60 wt%, in view of ensuring the printing or application suitability stably.

In addition, the composition may further contain other additives conventionally used for improving specific properties in the field of coating compositions, so long as the object of the present invention is not impaired. Specifically, in order to improve the coating film surface properties, binding power, coating properties, etc. of the coating composition together with the dispersant, it may include one or two or more of all of defoaming agents, interfacial bonding agents, leveling agents, thickeners and the like. The content of each of the other additives other than the dispersing agent may be 1 to 10 parts by weight based on 100 parts by weight of lacquer, but it is needless to say that the kind and content of the other additives can be suitably changed in consideration of the application method and the use of the coating film.

 The composition according to an embodiment of the present invention may be a composition for electrification prevention, electrostatic dissipation (ESD), conductive coating film, and / or electromagnetic wave shielding, and is more effective for shielding electromagnetic waves.

The present invention includes a substrate including a coated film on which the above-described lacquer coating composition is applied and dried. Specifically, the base material including the coating film on which the above-described lacquer coating composition is applied and dried can be used as an antistatic agent, an electrostatic dispersion, a conductive film, an electromagnetic wave shielding material, an electromagnetic wave absorbing material, a solar battery electrode, (P-EDLC) or a capacitor, an electrochemical device, a semiconductor device, a photoelectric device, and a photoelectric device using the same. (PDP) parts, PSP parts, parts for game machines, housings, transparent electrodes, opaque electrodes, field emission displays (FEDs), back light units (BLUs), liquid crystal displays A liquid crystal display (LCD), a plasma display panel (PDP), a light emitting diode (LED), a heating element, a radiator, an automobile part, a ship part, It can be a clean room, transportation equipment parts, flame-retardant materials, antibacterial materials, medical equipment, construction materials, flooring, wallpaper, light parts, touch panels, billboard, billboards, displays, lamps, optics, military and electronic components.

The present invention includes a method for producing a conductive lacquer coating composition. In describing the method of manufacturing the conductive lacquer coating composition according to the present invention, the materials and the mixed contents of lacquer, conductive carbon material, metal particle, non-aqueous solvent and dispersant are similar to or the same as those described above in the conductive lacquer coating composition, , The method for preparing a conductive lacquer coating composition according to the present invention includes all the contents mentioned above in the conductive lacquer coating composition.

A method for preparing a conductive lacquer coating composition according to the present invention comprises the steps of: a) mixing a lacquer with a conductive carbon material having a one- or two-dimensional nanostructure and metal particles to prepare a primary mixture; And b) mixing and stirring the non-aqueous solvent and the dispersant in the primary mixture. The stirring of step a) and step b) may be carried out independently of each other using one or more selected from conventional stirrer, ball mill and 3-roll mill. However, for faster homogenous mixing, it is advantageous that stirring in step a) is carried out with a three-roll mill with a predominant shearing force.

The present invention includes a method for producing a coating film using the above-described conductive lacquer coating composition. In detail, the method for producing a coating film according to the present invention comprises the steps of forming a coating film by applying the conductive lacquer coating composition described above; And drying the coating film to form a conductive coating film. In this case, it is needless to say that the coating film may be formed on one surface of the substrate on which the conductive coating film is to be formed, or on the entire surface of the substrate, in consideration of its use.

The application of the conductive coating composition can be carried out by various methods such as bar coating, gravure coating, microgravure coating, flexo coating, knife coating, spray coating, slot die coating, roll coating, screen coating, inkjet printing, casting, But it is needless to say that the present invention can not be limited by a specific application method, but it is needless to say that the present invention can be applied to any one or more methods selected from flow coating, curtain coating, comma coating, kiss coating, pad printing and spin coating .

Drying of the coating film may be carried out under ordinary conditions known to dry the lacquer. However, since it is advantageous to dry the lacquer after the non-aqueous solvent contained in the coating composition is removed from the non-aqueous solvent, the lacquer is dried (cured) after the primary drying, It can be multi-stage drying, including tea drying. The primary drying may be reduced pressure drying or natural volatilization (room temperature drying). Secondary drying can be carried out under conditions of a temperature of 20 to 30 DEG C and a humidity (relative humidity) of 70 to 80%, as is known for drying (curing) conditions of lacquer.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, it should be understood that the present invention is not limited to the following examples.

(Production Example 1)

Manufacture of refined lacquer by traditional method

In order to prepare refined lacquer from natural lacquer, 1kg of Chinese fresh green was filtered with a filter paper to filter out foreign matters, and the mixture was put into a mixing device and mixed for 5 hours to evaporate water to make 644g of transparent lacquer.

Also, in order to measure the dryness of the prepared traditional lacquer, it was coated on a glass plate and placed in a drying chamber adjusted to a humidity of 80% and a temperature of 25 ° C, followed by drying for 12 hours.

(Production Example 2)

Preparation of refined lacquer by recombinant method

In order to prepare purified lacquer from natural lacquer by recombinant method, 1kg of Chinese fresh green and 2.5kg of acetone were added, mixed and filtered under reduced pressure. After washing with 0.5 kg of acetone, the filtrate was evaporated in a vacuum evaporator to obtain 558 g of urushiol. The acetone-insoluble compound was allowed to stand at room temperature for 2 days and dried to obtain 65 g.

In order to prepare purified lacquer by recombinant method, 12 g of acetone-insoluble compound was added with 36 g of distilled water, and 100 g of urushiol was added thereto. The mixture was stirred and mixed with a spatula until it became a transparent light brown color on the glass plate. As a result, urushiol and acetone-insoluble compounds and distilled water became milky white and water was evaporated while forming micelles. Thus, transparent lacquer of clear brown color was prepared. 116 g of purified lacquer having a moisture content of 3.44 wt% and a catechol content of 86 wt% .

Also, in order to measure the dryness of the conventional lacquer, it was cured in 8 hours as a result of drying on a glass plate and drying in a drying chamber adjusted to a humidity of 80% and a temperature of 25 ° C.

(Example 1)

As a previous experiment, 19.25 g of refined lacquer manufactured in the preparation example 2, 30 g of silver powder (FAG 30A, 4.36 탆) in flake form and 0.75 g of multi-walled carbon nanotubes (MWCNT, CM-250, Hanhwa) The mixture was mixed with 3-roll mill to prepare a mixture of lacquer-carbon nanotube-metal particles. The mixture was placed in a transparent closed container and allowed to stand at room temperature for 30 days. As a result, Was maintained in a stable and uniformly dispersed state.

(MWCNT, CM-250, Hanhwa), 30 g of silver powder (FAG 30A, 4.36 [mu] m) in flake form and 30 g of purified lacquer prepared in the recombinant method in Production Example 2, 12 g of N-methylpyrrolidone (NMP), 35.6 g of terphenyl oil and 1.2 g of BYK-192 and BYK-9076 as a dispersing agent were added to a nonaqueous solvent, and the mixture was stirred with a mechanical stirrer And 100 g of a lacquer paint was prepared by mixing and stirring.

The lacquer paint was transferred onto a 15x15cm glass plate and then pressed with a bar code to make a film. The plate was allowed to stand at room temperature for 1 hour to naturally evaporate the solvent, and then dried in a lacquer drying apparatus at a temperature of 25 ° C and a humidity of 80% for 24 hours To prepare a coating film having a thickness of about 13 탆.

(Example 2)

14.25g Lacquer paint and coating film were prepared in the same manner as in Example 1, except that refined lacquer, 35g of silver powder and 0.75g of multi-walled carbon nanotubes were mixed.

(Example 3)

Lacquer paint and coating film were prepared in the same manner as in Example 1, except that 24g of refined lacquer, 25g of silver powder and 1.0g of multi-walled carbon nanotubes were mixed.

(Example 4)

19g A lacquer paint and a coating film were prepared in the same manner as in Example 1, except that the tablet lacquer, 30g of silver powder and 1.0g of multi-walled carbon nanotubes were mixed.

(Example 5)

Lacquer paint and coating film were prepared in the same manner as in Example 1, except that 14g of refined lacquer, 35g of silver powder and 1.0g of multi-walled carbon nanotubes were mixed.

(Comparative Example 1)

1.5 g of multi-walled carbon nanotubes (MWCNT, CM-250, Hanhwa) were mixed in a three-roll mill into 50 g of the lacquered tablet prepared in Production Example 2 by recombinant method, and then N-methylpyrrolidone (NMP ), 34.1 g of terphenyl oil, 1.2 g of BYK-192 and BYK-9076 as dispersing agents, respectively, and the mixture was mixed and stirred with a mechanical stirrer to prepare a coating composition. Thereafter, a coating film was produced under the same conditions as in Example 1.

(Comparative Example 2)

35 g of flake form silver powder (FAG-30A) was mixed in 15 g of purified lacquer prepared in Production Example 2 by a 3-roll mill, and then 12 g of N-methylpyrrolidone (NMP) And 1.2 g of BYK-192 and BYK-9076 as dispersing agents, respectively, and the mixture was mixed and stirred with a mechanical stirrer to prepare a coating composition. Thereafter, a coating film was produced under the same conditions as in Example 1.

(Comparative Example 3)

In Comparative Example 2, a coating composition and a coating film were prepared in the same manner as in Comparative Example 2, except that 40 g of silver powder was mixed with 10 g of stained lacquer.

Surface resistance measurement: The surface resistance of the coated film was measured by a surface resistance meter to measure the surface resistance of at least 5 points. The surface resistivity was measured using a static solution RT-1000 with surface resistances ranging from 10 ³ to 10 ¹⁰ Ω / □ and less than 10 ³ Ω / □ using a Loresta-GP (MCP-T610) surface resistivity meter from Mitsubishi Chemical Respectively.

Measurement of Electromagnetic Wave Shielding Efficiency: In order to measure the electromagnetic wave shielding efficiency, a coating film was prepared in the same manner on Bakelite plate of 1 mm thickness instead of a glass plate in each of Examples 1 to 5, and a coating film was prepared using a network analyzer (E5071C model) The electromagnetic shielding effect in the range of 30MHz ~ 1.5GHz was measured and the average value was calculated by applying the measurement standard and method.

Table 1 below shows the silver powder (Ag flake in Table 1), carbon nanotubes (MWCNT in Table 1), refined lacquer, non-aqueous solvent (terphenyl oil and NMP) and dispersant (BYK -192 and BYK-9076), the surface resistance of the prepared coating film, and the electromagnetic wave shielding efficiency.

(Table 1)

Examples 1 to 5 and Comparative Examples 1 to 3 were prepared in the same manner as in Example 1, except that the total solid content (purified lacquer, carbon nanotube and silver powder) in the composition, which is a condition for ensuring stable application suitability, It is the result of the experiment which examines the relative content, the surface resistance and the shielding efficiency depending on whether or not the silver powder is contained or the carbon nanotubes are contained.

As summarized in Table 1, when using carbon nanotubes alone as Comparative Example 1, it is difficult to have a surface resistance of ⁴ x 10 ² ? /? Or less. When silver powder alone was used as in Comparative Example 2 and Comparative Example 3 It is difficult to show a surface resistance of ¹ x ¹⁰ < ³ > OMEGA / & squ & or less even when silver powder ranging from 70 to 80 wt% of the total solid content (lacquer and silver) is used.

In Examples 1 and 2, the content of silver powder was varied at a content of carbon nanotubes of 0.75% by weight, and in Examples 3 to 5, the content of silver powder was varied at a content of carbon nanotubes of 1.0% by weight. As can be seen from Table 1, it can be seen that Example 2 and Example 5 have the lowest surface resistance value. In Example 5, however, the surface resistance was not significantly different from that in Example 2, but the content of carbon nanotubes was increased and the surface state of the prepared coating film was found to be rough.

Comparative Example 1 in which carbon nanotubes alone were added to lacquer and Comparative Example 2 and Comparative Example 3 in which silver powder in the form of flake was added alone to lacquer were compared with the surface resistance values of flake form and carbon nanotubes In the case of Examples 1 to 5, it can be confirmed that the surface resistance is remarkably reduced. It can be interpreted that carbon nanotubes and flake-shaped silver powder uniformly dispersed in the purified lacquer matrix form a stable conductive network when the flake-shaped silver powder and the carbon nanotube are used together, thereby exhibiting remarkably low surface resistance have.

FIG. 1 is a diagram showing a measurement result of electromagnetic wave shielding effect by wavelength for a coated film of Example 2 having excellent electrical characteristics. The unit representing the electromagnetic wave shielding effect is decibel (dB). The electromagnetic wave shielding efficiency after shielding is expressed as the electromagnetic wave intensity ratio before shielding as a normal log and then multiplied by 10. The shielding effect of 20dB is 1/100 in the electromagnetic shielding effect and 30dB The shielding effect of 40 dB means that the amount of electromagnetic waves is reduced to 1/10000. 30 ~ 60dB is good, 60 ~ 90dB is excellent, 90 ~ 120dB is the highest level. 1 and Table 1, it can be seen that the lacquer coating composition of the present invention has a very excellent electromagnetic shielding effect.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Those skilled in the art will recognize that many modifications and variations are possible in light of the above teachings.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

Claims (12)

Tablet lacquer having a moisture content of 5% by weight or less; A conductive carbon material including a single-wall carbon nanotube, a double wall carbon nanotube, a multi-wall carbon nanotube, a thin multi-wall carbon nanotube, a multiple carbon nanotube, or a mixture thereof; And metal particles.
delete The method according to claim 1,
Wherein the composition contains 1 to 10 parts by weight of a conductive carbonaceous material and 100 to 300 parts by weight of metal particles based on 100 parts by weight of purified lacquer. The method according to claim 1,
Wherein the composition further comprises a non-aqueous solvent and an additive comprising a dispersing agent. 5. The method of claim 4,
Wherein the composition contains 1 to 20 parts by weight of a dispersing agent based on 100 to 500 parts by weight of non-aqueous solvent and 100 parts by weight of non-aqueous solvent based on 100 parts by weight of purified lacquer. The method according to claim 1,
Wherein the metal particles are spherical or flake-shaped. The method according to claim 6,
Wherein the metal particles have a size distribution of Unimodal, Bimodal or Triimodal. The method according to claim 1,
Wherein the conductive carbon material further comprises graphene, reduced graphene oxide (RGO), or graphene and reduced graphene graphene. The method according to claim 1,
The metal particles may be silver particles; Platinum particles; Core-shell particles having a shell of silver or platinum on the core of a dissimilar metal different from silver or platinum; Or mixed particles thereof. The method according to claim 1,
Wherein the composition is for electromagnetic shielding. a) a single-walled carbon nanotube, a double-walled carbon nanotube, a multi-walled carbon nanotube, a thin multi-walled carbon nanotube, a multi-walled carbon nanotube or a mixture thereof in a tablet lacquer having a water content of 5 wt% Mixing and agitating the conductive carbon material and the metal particles in an unmodified state to prepare a first mixture; And
b) mixing the primary mixture with an additive including a non-aqueous solvent and a dispersing agent to prepare a conductive lacquer coating composition; and 11. A substrate comprising a coated and dried conductive lacquer coating composition according to any one of claims 1 to 10.

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