KR102377769B1 - A coating method using a ceramic composition - Google Patents

Abstract

One embodiment of the present invention provides a coating method which comprises: a step (a) of degreasing and washing a surface of a metal substrate by a surface treatment composition having a pH-dependent variable charge and containing a first substrate of which the bottom end or a surface is modified with a hydrophilic or hydrophobic functional group; and a step (b) of enabling at least two among a metal particle, a non-oxide ceramic particle, and an oxide ceramic particle to be surface-treated to have positive or negative charges to be electrostatically coupled to each other or continuously wet-coating a ceramic composition containing a co-dispersed second substance twice or more on a surface of the metal substrate and drying the coated surface.

Description

A coating method using a ceramic composition {A COATING METHOD USING A CERAMIC COMPOSITION}

The present invention relates to a coating method using a ceramic composition.

In modern quantum mechanics, it has been found that when the particle size of a material is reduced to the micrometer or nanometer level, qualitatively unique properties can be realized even in the same material, and accordingly, the control of the particle size of a material affecting the qualitative properties It has been shown that this can be a variable.

Recently, nanometer-scale ceramic particle materials have been widely used in various fields, and the possibility of their application is also increasing. In particular, as interest in BT fields such as biotechnology and medicine is growing, studies related to the synthesis, functionalization, and application of ceramic particles are being actively conducted.

In addition, in order to broaden the application range of ceramic particles, the degree of dispersion in the medium is very important. This is because, if the degree of dispersion of the ceramic particles is not maintained above a certain level, aggregation or agglomeration between particles may be accelerated and specific physical properties may be lost due to the particle size.

In contrast, a number of studies related to the surface treatment of ceramic particles using hydrophobic silicates such as Tetraethylorthosilicate (TEOS) and Tetramethoxysilane (TMOS) have been conducted. However, in the case of such a silica coating, although there is an advantage in that the electrical properties can be maintained by suppressing the agglomeration between particles, the mass productivity is poor and the magnetization ability is inevitably reduced. is being demanded

On the other hand, methods such as electrodeposition coating and electrostatic powder coating are known as coating methods for metal. In addition, it is subjected to a pretreatment step of forming a film to impart corrosion resistance, corrosion resistance, and coating film adhesion to the surface of the metal before coating. However, for coating accompanied by pretreatment, “hot water washing → preliminary degreasing → main degreasing → 1st water washing → 2nd water washing → surface adjustment → chemical conversion film → 3rd washing → 4th washing → drying → coating → 5th washing → drying” Productivity and efficiency are low, including complex and complex processes. In addition, since a heavy metal or a salt thereof is used as a material for forming the film, its use needs to be limited in terms of eco-friendliness.

Electrophoresis is a phenomenon in which cation particles in the solution move to the cathode and anion particles move to the anode when an electric current is passed through the solution, and this principle is applied to metal coating. Electrophoresis, electrolysis, electrocoagulation, electroosmosis, etc. occur when a metal object is placed in a container containing an electrodeposition coating material dispersed or dissolved in a solvent and a voltage is applied between the object and the electrode to form a coating film on the surface of the object. there is.

Since the electrodeposition coating corresponds to an electrical method, a certain level of conductivity must be imparted to the paint as well as the conductivity of the metal as a base material. It is important not to substantially decrease the intrinsic conductivity of the metal to substantially act as an insulating layer.

In addition, techniques for controlling the surface resistance of the substrate by controlling the composition of the paint, the number of times of coating, the coating method, etc. have been proposed, but independently developing the composition of the paint according to the required surface resistance is disadvantageous in terms of economic feasibility and mass productivity When the number of coatings is increased using an existing paint, the surface resistance not only changes rapidly, but it is difficult to control and predict the change pattern and range, and there is a problem in that the adhesion between the coating layers is lowered.

The present invention is to solve the problems of the prior art described above, and an object of the present invention is to have excellent adhesion and adhesion to a metal substrate even at a low voltage, to precisely control the surface resistance through a simple and economical process, and to be environmentally friendly. It is to provide a unique painting method.

One aspect of the present invention provides a method comprising the steps of: (a) degreasing and washing the surface of a metal substrate with a surface treatment composition comprising a first material having a pH-dependent variable charge and modified at a terminal or surface with a hydrophilic or hydrophobic functional group; and (b) a second material that is electrostatically coupled to or co-dispersed with each other by surface treatment such that at least two of the metal particles, the non-oxide ceramic particles, and the oxide ceramic particles have a positive or negative charge. It provides a coating method comprising a; after continuously wet coating the ceramic composition on the surface of the metal substrate two or more times, and then drying.

In an embodiment, the first material may be one selected from the group consisting of a zero valent metal, a metal salt, a ceramic compound, an ionic polymer, and a combination of two or more thereof.

In one embodiment, the content of the first material in the surface treatment composition may be 5 to 50% by weight.

In one embodiment, the surface treatment composition may further include an inorganic salt.

In one embodiment, the content of the inorganic salt in the surface treatment composition may be 5 to 50% by weight.

In one embodiment, the metal particles are Li, Be, Na, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Cs, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po, At, Fr, Ra, Ac, Th, Pa, U, Np, It may be one selected from the group consisting of Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lr, Rf, Db, Sg, Bh, Hs, and a combination of two or more thereof.

In one embodiment, the non-oxide ceramic particles may include one selected from the group consisting of Si, B, C, S, P, N, and a combination of two or more thereof.

In one embodiment, the oxide ceramic particles may include a metal component and O.

In one embodiment, the ceramic composition further comprises one binder resin selected from the group consisting of organic binders, inorganic binders, cationic polymers, anionic polymers, nonionic polymers, amphiphilic polymers, and combinations of two or more thereof. can

In an embodiment, the wet coating may be performed by applying a predetermined voltage between the metal substrate and the ceramic composition.

The coating method according to one aspect of the present invention is environmentally friendly and metal by degreasing and washing the surface of a metal substrate with a surface treatment composition comprising a material having a pH-dependent variable charge and modified with a hydrophilic or hydrophobic functional group at the terminal or surface. By simplifying the pretreatment process for the substrate, economical efficiency and productivity can be significantly improved.

In addition, in the coating method, by using a ceramic composition having excellent dispersibility and electrical conductivity when necessary, the surface of the metal substrate is continuously wet-coated two or more times and then dried, so that the adhesion between the metal substrate-coating film and the coating film-coating film, It has excellent adhesion and paintability, and can precisely control the surface resistance through a simple and economical process.

It should be understood that the effects of the present invention are not limited to the above-described effects, and include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention.

1 is a schematic diagram of a painting method according to an embodiment of the present invention.
2 is a TEM image of silica particles having a terminal or surface modified with gamma-aminobutyric acid (GABA) according to an embodiment of the present invention.
3 is a photograph evaluating the degreasing performance of the aluminum substrate of the surface treatment composition according to an embodiment of the present invention.
4 is a photograph evaluating the degreasing performance of the iron substrate of the surface treatment composition according to an embodiment of the present invention.
5 is an SEM image of a ceramic composition according to an embodiment of the present invention.
6 is an EDX mapping image of a ceramic composition according to an embodiment of the present invention.
7 is a TEM image of a ceramic composition according to an embodiment of the present invention.
8 is an SEM and EDX mapping image of a ceramic composition according to an embodiment of the present invention.
9 shows the results of measuring the particle size of the ceramic composition according to an embodiment of the present invention.

Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention may be embodied in several different forms, and thus is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part is "connected" with another part, this includes not only the case where it is "directly connected" but also the case where it is "indirectly connected" with another member interposed therebetween. . In addition, when a part "includes" a certain component, this means that other components may be further provided without excluding other components unless otherwise stated.

1 is a schematic diagram of a painting method according to an embodiment of the present invention. Referring to FIG. 1 , the coating method according to an embodiment of the present invention includes (a) a surface treatment composition comprising a first material having a pH-dependent variable charge and modified with a hydrophilic or hydrophobic functional group at the terminal or surface of the metal. degreasing and washing the surface of the substrate; and (b) a second material that is electrostatically coupled to or co-dispersed with each other by surface treatment such that at least two of the metal particles, the non-oxide ceramic particles, and the oxide ceramic particles have a positive or negative charge. It may include; after continuously wet-coating the ceramic composition on the surface of the metal substrate two or more times, drying the composition.

(a) degreasing and washing steps

In step (a), the surface of the metal substrate may be degreased and washed with a surface treatment composition including a first material having a pH-dependent variable charge and modified with a hydrophilic or hydrophobic functional group at a terminal or surface.

The first material may have a pH-dependent variable charge. As used herein, the term "pH-dependent variable charge" refers to a material in which the charge on the surface and/or inside of a material is converted to (+) and/or (-) or the amount of charge is changed depending on the surrounding pH .

The first material may be one selected from the group consisting of a zero valent metal, a metal salt, a ceramic compound, an ionic polymer, and a combination of two or more thereof.

The zero-valent metal is Li, Be, Na, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Cs, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po, At, Fr, Ra, Ac, Th, Pa, U, Np, Pu, Am, Cm, It may be one selected from the group consisting of Bk, Cf, Es, Fm, Md, No, Lr, Rf, Db, Sg, Bh, Hs, and a combination of two or more thereof, preferably, having an average particle size of a certain size In this case, it may be Cu, Pt, Au, Fe, Ag, which is relatively stable in a zero valent state, but is not limited thereto.

The metal salt is an ionic material composed of a metal cation and a non-metal anion, and the type thereof is not particularly limited.

The ceramic compound may be a non-oxide ceramic, an oxide ceramic, or a combination thereof.

The non-oxide ceramic may be one selected from the group consisting of Si, B, C, S, P, N, and a combination of two or more thereof, but is not limited thereto.

The non-oxide ceramic may be one selected from the group consisting of boride ceramics, carbide ceramics, nitride ceramics, silicide ceramics, and combinations of two or more thereof, but is not limited thereto.

The boride ceramics are BaB ₆ , CeB ₆ , Co ₂ B, CoB, FeB, GdB ₄ , GdB ₆ , LaB ₄ , LaB ₆ , Mo ₂ B, MoB, MoB ₂ , Mo ₂ B ₅ , Nb ₃ B ₂ , NbB, Nb ₃ B ₄ , NbB ₂ , NdB ₄ , NdB ₆ , PrB ₄ , PrB ₆ , SrB ₆ , TaB, TaB ₂ , TiB, TiB ₂ , VB, VB ₂ , W ₂ B ₅ , YB ₄ , YB ₆ , YB ₁₂ , ZrB ₂ and may be one selected from the group consisting of a combination of two or more thereof, and the carbide ceramic is MoC, Mo ₂ C, Nb ₂ C, NbC, SiC, Ta ₂ C, TaC, TiC, V ₂ It may be one selected from the group consisting of C, VC, WC, W ₂ C and ZrC and a combination of two or more thereof, and the nitride ceramic is Mo ₂ N, Nb ₂ N, NbN, ScN, Ta ₂ N, TiN and ZrN And it may be one selected from the group consisting of a combination of two or more of these, the silicide ceramic is CoSi ₂ , Mo ₃ Si, Mo ₅ Si ₃ , MoSi ₂ , NbSi ₂ , Ni ₂ Si, Ta ₂ Si, TaSi ₂ , TiSi , TiSi ₂ , V ₅ Si ₃ , VSi ₂ , W ₃ Si, WSi ₂ , ZrSi and ZrSi ₂ It may be one selected from the group consisting of a combination of two or more thereof, but is not limited thereto.

The oxide ceramic may include a metal component and O, preferably from the group consisting of SiO ₂ , TiO ₂ , MgO, Al ₂ O ₃ , Fe ₂ O ₃ , Fe ₃ O ₄ and combinations of two or more thereof. It may be one selected, but is not limited thereto.

At least one of the non-oxide and the oxide ceramic may be surface-treated to be electrostatically coupled to each other or to be co-dispersed.

The surface treatment is acid, base, halogen element, silane-based compound, metal ionic material, carbamic acid, polar solvent, protic solvent, aprotic solvent, non-polar solvent, electrolyte, metal salt, non-metal salt, amine-based compound, carboxylic acid It may be a chemical surface treatment by one selected from the group consisting of a carboxyl-based compound, a charge control agent, UVO (ultraviolet ozone), and a combination of two or more thereof.

The acid treatment may be performed with one selected from the group consisting of nitric acid, sulfuric acid, acetic acid, hydrochloric acid, and a combination of two or more thereof, but is not limited thereto. In addition, the base treatment may be performed with one selected from the group consisting of ammonia, potassium hydroxide, calcium hydroxide, magnesium hydroxide, sodium hydroxide, and a combination of two or more thereof, but is not limited thereto.

When the non-oxide and/or the oxide ceramic is treated with an acid or a base, a positive charge or a negative charge is applied to the non-oxide and/or the oxide ceramic through an IEP (Isoelectric point) change can do. At this time, a positive charge may be imparted in the range of pH 2-5, preferably pH 2-3, and a negative charge may be imparted in the range of pH 5-10, preferably pH 7-10. This is because H ⁺ surrounds the non-oxide and/or the oxide ceramic under an acid atmosphere, making the particles more likely to have a positive charge overall, and under a basic atmosphere OH ⁻ surrounds the non-oxide and/or the oxide ceramic As a result, the particle as a whole has a negative charge.

The non-oxide and/or the oxide ceramic may be surface-treated using one selected from the group consisting of the halogen element, silane-based compound, metal ionic material, carbamic acid, and a combination of two or more thereof.

The halogen element may be selected from the group consisting of F, Cl, B, I, and a combination of two or more thereof, and the silane-based compound may be, for example, aminopropyl trimethoxysilane, but in this It is not limited.

The acid, base, halogen element, silane compound, metal ionic substance, carbamic acid, polar solvent, protic solvent, aprotic solvent, non-polar solvent, electrolyte, metal salt, non-metal salt, amine compound, carboxyl compound When the non-oxide and/or the oxide ceramic is surface treated using one selected from the group consisting of , a charge control agent, ultraviolet ozone (UVO) and a combination of two or more thereof, the non-oxide and/or the oxide ceramic Alternatively, an energy barrier through which the surface of the oxide ceramic may be electrically activated exists in a low state.

In addition to the surface treatment, UV-ozone generator (UVO; Ultraviolet Ozone), plasma, heat, ultrasonic treatment and two or more of these methods may be additionally performed, and preferably heat or ultrasonic treatment, but limited thereto not.

The UV-ozone generator treatment may modify the surface by removing the non-oxide and/or contaminants present on the surface of the oxide ceramic. UV irradiation time may be about 1 to 4 hours, preferably, may be 2 to 3 hours, but is not limited thereto. If the irradiation time is less than 1 hour, the non-oxide and/or the oxide ceramic surface is not efficient in removing contaminants, especially organic contaminants, and the degree of imparting hydrophilicity is weak. If the irradiation time is more than 4 hours, the process efficiency may be reduced.

The UV-ozone generation wavelength may be 185 or 254 nm, preferably, 254 nm, but is not limited thereto. If the UV-ozone generating wavelength is 185 nm, organic contaminants present on the surface of the non-oxide and/or the oxide ceramic can be decomposed into hydrogen and carbon, and when the UV-ozone generating wavelength is 254 nm, ozone is generated from oxygen molecules to produce organic substances Hydrogen provided from the hydrogen and carbon may be combined to remove organic matter, and hydrophilicity may be imparted to the surface of the non-oxide and/or oxide ceramic.

The surface treatment may be a physical or physicochemical surface treatment by one selected from the group consisting of heat, plasma, ultrasonic waves, milling, and a combination of two or more thereof.

In the plasma treatment, plasma gas contains ions, electrons, atoms, molecules, etc., unlike general gases, and has high energy to modify the surface of a material. By forming a hydrophilic property to the surface of the non-oxide and/or the oxide ceramic can be imparted.

The heat treatment may be performed at 30 ~ 300 ℃, preferably, may be 60 ~ 90 ℃, but is not limited thereto. If the heat treatment temperature is less than 30 ℃, the surface treatment of the non-oxide and/or the oxide ceramic is not performed properly, and if it is more than 300 ℃, there may be a problem that the surface of the non-oxide and/or the oxide ceramic is oxidized due to the high temperature. can

The ultrasonic treatment causes three representative physical phenomena: fluid cavitation, local heating, and free radical formation. Fluid cavitation may induce the dispersion and functional groups of the non-oxide and/or the oxide ceramic by the generation of bubbles and the force by the explosion. In addition, local heating occurs due to high energy supply, and it is effective to remove impurities strongly adsorbed on the surface of the non-oxide and/or the oxide ceramic due to the formation of free radicals.

The ultrasonic treatment may be performed for 30 to 150 minutes, preferably, 50 to 70 minutes, but is not limited thereto. If the ultrasonic treatment time is less than 30 minutes, it is difficult to sufficiently remove impurities present on the surface of the non-oxide and/or the oxide ceramic, and if it exceeds 150 minutes, the surface of the non-oxide and/or the oxide ceramic due to high energy injection This can be damaged.

The milling treatment may be performed by a wet method, a dry method, or a combination of wet and dry methods. Through the milling process, the non-oxide and/or the oxide ceramic may be pulverized to have a uniform particle size, and the reactivity of the non-oxide and/or the oxide ceramic may be increased by surface friction between particles.

The material may be particles having an average particle size of 1 to 50,000 nm, preferably, 1 to 10,000 nm. If the average particle size of the particles is less than 1 nm, it may not be easy to manufacture nanometer-sized particles. This weakens the degreasing and rust prevention performance may be reduced.

The shape of the particle may be one selected from the group consisting of rod, spherical, square, flake, and a combination of two or more thereof, and preferably, may be a sphere, but It is not limited. In addition, the particles may further include irregular shapes, such as a star shape, a trapezoid, or an octahedron. The shape of the particles is not limited to those exemplified above, and in addition, two or more of rods, spheres, squares, and flakes are mutually combined or one of them is partially modified, for example, hemispheres, ellipsoids , a hollow body, a rectangle, a trapezoid, a rhombus, a parallelogram, and the like.

The ionic polymer refers to a polymer having one or more ionic functional groups in a main chain or a side chain. For example, polyacrylamide is a cationic polymer having an amino group as a cationic functional group, and polyacrylic acid is an anionic polymer having a carboxyl group as an anionic functional group. In addition, polymers having both cationic and anionic functional groups as well as cationic polymers are referred to as amphoteric polymers.

The ionic polymer is mainly used as a seat for adsorption bonding of solutes such as water, dyes, light absorbers, ceramics, and various processing agents by using the reactivity of these ions. It can be widely used in products requiring these properties. The solution properties of the ionic polymer have an unfolded form due to the repulsive force of side chain ions having the same polarity in a pure solution, but when amphoteric or salt is present in a solvent, intramolecular bonding is induced through salt. It may have a coiled form. In this case, not only intramolecular bonding, but also secondary bonding between neighboring molecules may easily occur. The secondary bond by polar van der Waals is capable of reversible dissociation-bonding depending on the temperature, that is, the strength of molecular motion.

As described above, the terminal or surface of the first material having a pH-dependent variable charge may be modified with a hydrophilic or hydrophobic functional group, preferably, a hydrophilic functional group.

The hydrophilic functional group may include a functional group including one halogen selected from the group consisting of a fluoro group, a chloro group, a bromo group, an iodo group, and a combination of two or more thereof; Hydroxyl group, carbonyl group, haloformyl group, carbonate ester group, carboalkoxy group, methoxy group, ethoxy group, hydroperoxy group, peroxy group, ether group, hemiacetal group, hemiketal group, acetal group, ketal group, a functional group containing one oxygen selected from the group consisting of an orthoester group, a methylenedioxy group, an orthocarbonate ester group, a carboxylic acid anhydride group, and combinations of two or more thereof; Amide group, amine group, imine group, imide group, azide group, azo group, cyan group, nitric acid group, nitrile group, isonitrile group, nitrosooxy group, nitro group, nitroso group, oxime group, pyridyl group, carboxyl group a functional group containing one nitrogen selected from the group consisting of a bamoyloxy group and a combination of two or more thereof; Thiol group, sulfide group, sulfinyl group, sulfonyl group, sulfino group, sulfo group, thiocyanate group, isothiocyanate group, carbonothioyl group, thiocarboxylic acid group, dithiocarboxylic acid group, dithiocarsolic acid a functional group containing one sulfur selected from the group consisting of an ester group and a combination of two or more thereof; a functional group containing one phosphorus selected from the group consisting of a phosphino group, a phosphoric acid group, and a combination of two or more thereof; a functional group containing one boron selected from the group consisting of a borono group, a boronate group, a borino group, and a combination of two or more thereof; And it may be one selected from the group consisting of a combination of two or more of them, but is not limited thereto.

Preferably, the hydrophilic functional group is one selected from the group consisting of a carboxyl group (-COOH), an amine group (-NH ₂ ), a sulfonic acid group (-SO ₃ H), a hydroxyl group (-OH), and a combination of two or more thereof. may be, and preferably, a carboxyl group (-COOH) or an amine group (-NH ₂ ), but is not limited thereto.

The hydrophobic functional group may be one hydrocarbon group selected from the group consisting of an alkyl group, an alkenyl group, an alkynyl group, a phenyl group, a benzyl group, and a combination of two or more thereof, but is not limited thereto.

In order to modify the first material, a method of chemically substituting a terminal or surface of the first material with a hydrophilic or hydrophobic functional group, electrostatic interaction of the first material with a compound having a hydrophilic or hydrophobic functional group by inducing these The method of mutual coupling, etc. are mentioned. Among these, a method of chemically substituting a terminal or surface of the first material with a hydrophilic or hydrophobic functional group is known, for example, a silica (SiO ₂ ) particle whose terminal or surface is substituted with a functional group having a carboxyl group or an amine group. has been prepared by Sigma Aldrich et al.

When the first material and the compound having a hydrophilic or hydrophobic functional group cause electrostatic interaction to bond them together, for example, a functional group of the compound having the hydrophilic or hydrophobic functional group and the surface of the particle made of the first material may be electrostatically coupled to each other.

The compound having a hydrophilic or hydrophobic functional group may be a low molecular weight compound or a high molecular compound including one or more pendant functional groups. As used herein, the term "pendant functional group" refers to a functional group located at a location other than the chain end of a chain compound, in particular, a functional group grafted directly or indirectly to a side chain of a chain compound, a cyclic compound It may be understood to include a functional group bonded directly or indirectly to a ring atom of In addition, as used herein, the term "indirectly grafted (or bonded) functional group" refers to an end of a branched chain extending from a position (or a ring atom of a cyclic compound) other than both ends of the chain compound. It means a bound functional group.

The compound having the hydrophilic or hydrophobic functional group may be dissolved in a solvent to be ionized into hydrogen ions and anionic compounds, and the ionized hydrogen ions may impart a (+) charge to the surface of the particles made of the first material. At the same time, the anionic compound may remain irregularly dispersed in the solution, but after going through a predetermined step, a pendant functional group having a negative charge in the anionic compound and the particle having a (+) charge As the surfaces of the particles face each other and are electrostatically bound, the surface of the particle may be charged with a (-) charge.

That is, the compound having the hydrophilic or hydrophobic functional group performs both the roles of an acid and a base in an ionized or dissolved state, thereby buffering a sudden change in concentration of the acid or base, thereby controlling reactivity. In addition, uniform dispersion of the particles can be induced by simply controlling the concentration of the compound having the hydrophilic or hydrophobic functional group, the reaction temperature, and the pH of the reaction system.

For example, when the compound having a hydrophilic or hydrophobic functional group is gamma-aminobutyric acid (GABA), a hydrogen atom of a carboxyl group located at one end of GABA is ionized with a hydrogen ion, and at this time, the ionized Hydrogen ions may impart a (+) charge to the surface of the particle.

The anionic compound produced as the hydrogen atom is ionized is a loss of a hydrogen atom from one end of GABA, has a local (-) charge at the site where the atom is lost, and may remain irregularly in solution, but in a certain process, e.g. For example, a (-) charge may be imparted to the surface of the particle by arranging and bonding along the surface of the particle charged with a (+) charge through a heating process.

That is, by sequentially applying (+) and (-) charges to the surface of the particles by GABA, an electrostatic force may be generated between the particles, and thus dispersion between particles may be improved. , the electrical properties of the particles themselves can also be further stabilized.

2 is a TEM image of silica particles having a terminal or surface modified with gamma-aminobutyric acid (GABA) according to an embodiment of the present invention. Referring to FIG. 2 , GABA is electrostatically coupled along the surface of silica particles having an average particle size of about 400 nm to form a layer having a thickness of about 12.02 nm.

The content of the first material in the surface treatment composition may be 5 to 50% by weight, preferably, 10 to 40% by weight, more preferably, 10 to 20% by weight. If the content of the first material is less than 5% by weight, solubility in the composition is good, but economic efficiency may be reduced by increasing the amount of other components, for example, degreasing agent, etc., and if it exceeds 50% by weight, economical efficiency is good, whereas the composition Solubility and dispersibility in medium may be lowered, and storage stability may be lowered.

The surface treatment composition may further include a surfactant. The surfactant may be one selected from the group consisting of cationic surfactants, anionic surfactants, amphoteric surfactants, nonionic surfactants, natural surfactants, and combinations of two or more thereof.

The cationic surfactant is a quaternary ammonium compound, benzalkonium chloride, cetyltrimethylammonium bromide, chitosan, lauryldimethylbenzylammonium chloride, acylcarnitine hydrochloride, alkylpyridinium halide, cetylpyridinium chloride, cationic lipid , polymethyl methacrylate trimethylammonium bromide, sulfonium compound, polyvinylpyrrolidone-2-dimethylaminoethyl methacrylate dimethyl sulfate, hexadecyltrimethylammonium bromide, phosphonium compound, benzyl-di (2-chloroethyl ) ethylammonium bromide, decyltriethylammonium chloride, decyldimethylhydroxyethylammonium chloride bromide, (C12-C15)dimethylhydroxyethylammonium chloride, (C12-C15)dimethylhydroxyethylammonium chloride bromide, myristyltrimethylammonium methyl Sulfate, lauryldimethylbenzylammonium chloride, lauryldimethylbenzylammonium bromide, lauryldimethyl (ethenoxy) quaternary ammonium chloride, lauryl dimethyl (ethenoxy) quaternary ammonium bromide, N-alkyl (C12-C18) dimethyl It may be one selected from the group consisting of benzylammonium chloride, N-alkyl (C14-C18) dimethyl-benzylammonium chloride, N-tetradecyldimethylbenzylammonium chloride, derivatives thereof, and combinations of two or more thereof, but is limited thereto not.

The anionic surfactant is ammonium lauryl sulfate, sodium 1-heptanesulfonate, sodium hexanesulfonate, sodium dodecyl sulfate, triethanolammonium dodecylbenzene sulfate, potassium laurate, triethanolamine stearate, lithium dodecyl sulfate, sodium la Uryl sulfate, sodium laureth sulfate, sodium heptanoate, sodium gluconate, sodium cetyl sulfate, sodium thiosulfate, sodium chondroitin sulfate, sodium polyoxyethylene lauryl ether sulfate, alkyl polyoxyethylene sulfate, sodium alginate, dioctyl Sodium sulfosuccinate, disodium laureth sulfosuccinate, phosphatidylglycerol, phosphatidylinositol, phosphatidylserine, phosphatidic acid and salts thereof, glyceryl ester, sodium carboxymethylcellulose, bile acids and salts thereof, cholic acid, deoxycholic acid , glycocholic acid, taurocholic acid, glycodeoxycholic acid, alkylsulfonate, arylsulfonate, alkylphosphate, alkylphosphonate, stearic acid and salts thereof, calcium stearate, phosphate, sodium carboxymethylcellulose, dioctylsulfosucci It may be one selected from the group consisting of nates, dialkyl esters of sodium sulfosuccinic acid, phospholipids, calcium carboxymethylcellulose sodium sulfate, derivatives thereof, and combinations of two or more thereof, but is not limited thereto.

The nonionic surfactant is methanol, ethanol, isopropanol, butanol, benzyl alcohol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,6-hexanediol, 1,2-propanediol, 1 ,3-propanediol, trimethylolpropane, sorbitol, xylitol, glycerin, diglycerin, ethylene glycol, diethylene glycol, polyethylene glycol, ethylene glycol monomethyl ether, ethylene glycol phenyl ether, propylene glycol, dipropylene glycol, tripropylene glycol , polypropylene glycol, propylene glycol monomethyl ether, propylene glycol phenyl ether, dibutyl diglycol, 3-methyl-3-methoxybutanol, 2-(2-butoxyethoxy) ethanol, polyoxyethylene alkyl ether, poly oxyethylene hydrogenated castor oil, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene fatty alcohol, polyoxyethylene alkylphenyl ether, polysorbate, sorbitan oleate, lactic acid, glucose, lauryl glucoside, Brij ^TM , Solsperse ^TM , Triton ^TM X-100, derivatives thereof, and may be one selected from the group consisting of a combination of two or more thereof, but is not limited thereto.

The amphoteric surfactant is, acetate (system), imidazole (system), betaine (system), phosphatide (system) compound, EDTA (ethylene diamine tetra acetic acid), derivatives thereof, and combinations of two or more thereof It may be one selected from the group consisting of, but is not limited thereto.

In particular, EDTA (ethylene diamine tetra acetic acid) is a chelating agent that forms a complex with metal ions, and as a compound containing two or more lone pairs of electrons, forms a coordination bond with the metal ion to form a stabilized chelate ring to form a metal ion. It can act as a stabilizing, so-called sequestering agent. The EDTA compound may be one selected from the group consisting of EDTA-4H, EDTA-2Na, EDTA-4Na, and a combination of two or more thereof, but is not limited thereto.

The natural surfactant may be, but is not limited to, an enzyme, a vegetable oil such as soap nut, corn starch, potato starch, rice water, coconut oil, and a combination of two or more thereof.

These surfactants can improve the dispersibility, stability, and lifespan characteristics of the surface treatment composition, and can improve the wettability of the surface treatment composition by wetting and penetrating the contaminants attached to the surface of the metal substrate, and saponification Reaction and emulsification can be promoted to improve degreasing and cleaning performance.

The content of the surfactant in the surface treatment composition may be 1 to 15% by weight, preferably, 1 to 10% by weight. If the content of the surfactant is less than 1% by weight, the surface tension of the surface treatment composition may be increased to decrease the degreasing performance, and if it is more than 15% by weight, a large amount of bubbles may be generated, thereby reducing workability.

The surface treatment composition may further include an inorganic salt, preferably, an aqueous inorganic salt. The inorganic salt is the main coating component in the surface treatment composition, and by forming a strong continuous phase film on the surface of the metal substrate, direct contact between the metal substrate and the tool is prevented, or other components including the lubricating component are used. It is possible to express a function and the like to be retained in the film. In addition, since the melting point of the film made of the inorganic salt is generally higher than the temperature reached by the material during cold plastic working, the lubricating film layer based on it is not easily affected by the processing heat, so that this function can be stably implemented.

The inorganic salt includes sulfate, borate, silicate, carbonate, phosphate, magnesium salt, silver salt, molybdate, tungstate, vanadate, zirconate, titanate, hafnate, fluoride ion-containing inorganic salt, and combinations of two or more thereof. It may be one selected from the group consisting of. The inorganic salt may be a metal salt with improved corrosion resistance, heat resistance, and eco-friendliness, and it has a pH-dependent variable charge, and is dissolved and alkalized with a material whose terminal or surface is modified with a hydrophilic or hydrophobic functional group, a surfactant, etc. When the metal substrate is immersed or sprayed for a certain period of time by adjusting the , pH, concentration, etc. under certain conditions, the process of cleaning and degreasing the surface of the metal substrate and the process of precipitating the coating material on the surface of the metal substrate can be performed simultaneously.

Specifically, since various contaminants (processing oil, metal powder, etc.) are attached to the surface of the metal substrate during the process of pressing and cutting processing, it is lithified with an alkali solution, emulsified, and dispersed Contaminants need to be removed. At the same time, on the surface of the metal substrate, one or more of the metal ions included in the metal salt are deposited on the surface of the metal substrate by forming a coating material of an insoluble compound in the form of fluoride, hydroxide, and oxide while the pH is locally increased. Adhesion and corrosion resistance may be improved. The film derived from the inorganic salt may be deposited and adhered to the surface of the metal substrate in the form of a fine thin film.

The fluoride ion-containing inorganic salt may serve to dissolve and remove the Si component present on the etched substrate, and its types include acidic ammonium fluoride (NH ₄ HF ₂ ), ammonium fluoride (NH ₄ F), Or a combination thereof may be mentioned, but is not limited thereto.

The content of the inorganic salt in the surface treatment composition may be 5 to 50% by weight, preferably, 20 to 40% by weight. If the content of the inorganic salt is less than 5% by weight, the precipitation time of the inorganic salt on the surface of the metal substrate to be coated may take a long time, thereby reducing productivity. speed, and the loss of the composition for the movement of the coated object in the production line may increase, thereby reducing economic efficiency.

Meanwhile, the surface treatment composition may be aqueous or water-based. As used herein, the term "aqueous" or "aqueous" refers to a composition in which at least one of the components included in the surface treatment composition is dissolved in an aqueous solvent, for example, water, or the surface treatment composition is When one or more water-insoluble components are included, such water-insoluble components are uniformly dispersed in water in the form of particles, and may refer to a composition having a dispersion, suspension, emulsion or similar state.

The aqueous solvent is toluene, tetrahydrofuran, chloroform, cyclohexane, dioxane, dimethyl sulfoxide, dimethylformamide, acetone, acetonitrile, n-butanol, n-pentanol, chlorobenzene, ethylbenzene, dichloromethane, di Ethyl ether, tert-butanol, 1,2,-dichloroethylene, diisopropyl ether, ethanol, ethyl acetate, ethyl methyl ketone, heptane, hexane, isopropyl alcohol, isoamyl alcohol, methanol, pentane, n-propyl alcohol, Pentachloroethane, 1,1,2,2,-tetrachloroethane, 1,1,1,-trichloroethane, tetrachloroethylene, tetrachloromethane, trichloroethylene, water, xylene, benzene, nitromethane, It may be one selected from the group consisting of monoethanolamine, triethanolamine, amine solvent, propylene carbonate, dimethyl carbonate, ethylene carbonate, carbonate solvent, protic solvent, aprotic solvent, and combinations of two or more thereof, preferably may be ethylbenzene, isopropyl alcohol, or water, but is not limited thereto.

(b) an in-situ wet coating step

In step (b), a second material electrostatically coupled or co-dispersed to each other by surface treatment such that at least two of the metal particles, the non-oxide ceramic particles, and the oxide ceramic particles have a positive or negative charge. A ceramic composition comprising a, preferably, wet coating the conductive ceramic composition on the surface of the metal substrate two or more times successively, and then drying it to form a coating film having a surface resistance in a predetermined range.

The metal particles are Li, Be, Na, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Cs, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po, At, Fr, Ra, Ac, Th, Pa, U, Np, Pu, Am, Cm, It may be one selected from the group consisting of Bk, Cf, Es, Fm, Md, No, Lr, Rf, Db, Sg, Bh, Hs, and combinations of two or more thereof, and preferably, Sn particles, but It is not limited.

The non-oxide ceramic particles may include one selected from the group consisting of Si, B, C, S, P, N, and combinations of two or more thereof.

Carbon-based materials such as graphene, graphite, and CNT (carbon nanotube) have exceptionally high electrical conductivity, but ordinary ceramic particles have semiconductor properties, It does not show excellent properties. Accordingly, non-oxide ceramic particles including at least one of Si, B, C, S, P, and N were synthesized in a metal having excellent electrical conductivity.

The non-oxide ceramic particles may be one selected from the group consisting of boride ceramics, carbide ceramics, nitride ceramics, silicide ceramics, and combinations of two or more thereof, but is not limited thereto.

The boride ceramics are BaB ₆ , CeB ₆ , Co ₂ B, CoB, FeB, GdB ₄ , GdB ₆ , LaB ₄ , LaB ₆ , Mo ₂ B, MoB, MoB ₂ , Mo ₂ B ₅ , Nb ₃ B ₂ , NbB, Nb ₃ B ₄ , NbB ₂ , NdB ₄ , NdB ₆ , PrB ₄ , PrB ₆ , SrB ₆ , TaB, TaB ₂ , TiB, TiB ₂ , VB, VB ₂ , W ₂ B ₅ , YB ₄ , YB ₆ , YB ₁₂ , ZrB ₂ and combinations of two or more thereof, wherein the carbide ceramic is MoC, Mo ₂ C, Nb ₂ C, NbC, SiC, Ta ₂ C, TaC, TiC, V ₂ C, VC, B ₄ C, WC, W ₂ C, ZrC, and combinations of two or more thereof, wherein the nitride ceramic is Mo ₂ N, Nb ₂ N, NbN, ScN, Ta ₂ N, TiN, ZrN, SiAlON, and combinations of two or more thereof may be, the silicide ceramics are CoSi ₂ , Mo ₃ Si, Mo ₅ Si ₃ , MoSi ₂ , NbSi ₂ , Ni ₂ Si, Ta ₂ Si, TaSi ₂ , TiSi, TiSi ₂ , V ₅ Si ₃ , VSi ₂ , W ₃ Si, WSi ₂ , ZrSi, ZrSi ₂ and may be a combination of two or more thereof, but is not limited thereto.

In addition to the two-component ceramics, the non-oxide ceramic particle may be a three-component or more multi-component ceramics represented by AxByXn, AxByCzXn, or the like. A, B, and C are each Ag, Al, As, Au, Ba, Bi, Ca, Cd, Ce, Co, Cr, Cu, Fe, Ga, Gd, Ge, Hf, In, K, La, Li, Can be Mg, Mn, Mo, Na, Nb, Ni, P, Pb, Pr, Pt, Rb, S, Sc, Si, Sn, Sr, Ta, Ti, Tl, V, W, Y, Zn, or Zr and X may be Si, B, C, O, S, P, or N, and x, y, z, and n may each be an integer of 1 to 5.

The oxide ceramic particles may include a metal component and O, preferably, SiO ₂ , TiO ₂ , MgO, Al ₂ O ₃ , Fe ₂ O ₃ , Fe ₃ O ₄ and a group consisting of a combination of two or more thereof. It may be one selected from, but is not limited thereto.

At least two of the metal particles, the non-oxide ceramic particles, and the oxide ceramic particles may be surface-treated to have a positive or negative charge.

The surface treatment is acid, base, halogen element, silane compound, polymer, low molecular weight, resin, metal ionic material, carbamic acid, polar solvent, protic solvent, aprotic solvent, non-polar solvent, electrolyte, metal salt, non-metal salt , an amine compound, a carboxyl compound, a charge control agent, a dispersant, UVO (ultraviolet ozone), and a chemical surface treatment by one selected from the group consisting of a combination of two or more thereof.

The acid treatment may be performed with one selected from the group consisting of nitric acid, sulfuric acid, acetic acid, hydrochloric acid, phosphoric acid, and a combination of two or more thereof, but is not limited thereto. The base treatment may be performed with one selected from the group consisting of ammonia, potassium hydroxide, calcium hydroxide, magnesium hydroxide, sodium hydroxide, and a combination of two or more thereof, but is not limited thereto.

For example, when two or more (hereinafter, particles) of the metal particles, the non-oxide ceramic particles, and the oxide ceramic particles are treated with an acid or a base, a positive charge is applied to the particles through an IEP (Isoelectric point) change. Alternatively, a negative charge may be imparted. At this time, a positive charge may be imparted in the range of pH 1-7, preferably pH 2-5, and negative charge may be imparted in the range of pH 7-12, preferably pH 7-10. Under an acid atmosphere, H ⁺ surrounds the particle, so that the particle has a (+) charge, and under a basic atmosphere, OH ^- surrounds the particle, so that the particle has a negative charge.

The particle may be surface-treated using one selected from the group consisting of the halogen element, silane-based compound, polymer, low molecular weight, resin, metal ionic material, carbamic acid, and a combination of two or more thereof.

The halogen element may be selected from the group consisting of F, Cl, B, I and a combination of two or more thereof, and the silane-based compound may be Tetraethyl orthosilicate (TEOS), aminopropyltrimetoxysilane, but in this It is not limited.

The acid, base, halogen element, silane compound, polymer, low molecular weight, resin, metal ionic substance, carbamic acid, polar solvent, aprotic solvent, electrolyte, metal salt, non-metal salt, amine compound, carboxyl compound, When the surface is treated with one selected from the group consisting of a charge control agent, a dispersant, UVO (ultraviolet ozone), and a combination of two or more thereof, the energy at which the surface of the particle can be electrically activated The energy barrier remains low.

For example, a P-type or N-type semiconductor is used when manufacturing a semiconductor. A case in which there are many free electrons is called an N-type semiconductor, and a case in which the hole density is greater than the free electron density is called a P-type semiconductor. In this way, each functional group is given to the surface of the particle to surface-treat, thereby enriching electrons or enriching holes to change the mobility of electrons and facilitate charge transfer with other adjacent materials to facilitate the transfer of charges to the substrate. Electromagnetic capability can be improved by lowering the surface resistance of the substrate or increasing electrical conductivity.

In addition to the surface treatment, UV-ozone generator (UVO; Ultraviolet Ozone), plasma, heat, ultrasonic treatment, and two or more of these methods may be additionally performed, and preferably, heat and ultrasonic treatment may be used, but are limited thereto it is not

The UV-ozone generator treatment can modify the surface while removing contaminants from the surface of the particles. The UV may be irradiated for about 1 to 4 hours, preferably, 2 to 3 hours. If the irradiation time is less than 1 hour, it is difficult to remove contaminants from the surface of the particles, and the effect of imparting hydrophilicity is weak. If the irradiation time is more than 4 hours, the process efficiency may be reduced.

The irradiation distance of the UV-ozone generator may be 5 to 30 mm, preferably, 15 to 25 mm, but is not limited thereto. If the irradiation distance is less than 5 mm, the surface of the particles may be arbitrarily decomposed because the distance between UV-ozone and the particles is close. Do.

The UV-ozone generation wavelength may be 185 or 254 nm, preferably, 254 nm, but is not limited thereto. When the UV-ozone generation wavelength is 185 nm, organic contaminants present on the surface of the particles can be decomposed into hydrogen and carbon. It can bind with and remove organic matter and at the same time impart hydrophilicity to the surface of the particle.

The surface treatment may be a physical or physicochemical surface treatment by one selected from the group consisting of heat, plasma, ultrasonic waves, milling, and a combination of two or more thereof.

In the plasma treatment, the plasma gas contains ions, electrons, atoms, molecules, etc., unlike general gases, and has a very high energy, so it is possible to modify the surface of a material. By generating radicals, hydrophilicity can be imparted to the surface of the particles.

The heat treatment may be performed at 30 ~ 300 ℃, preferably, 50 ~ 150 ℃. If the heat treatment temperature is less than 30° C., it is difficult to modify the surface of the particles, and if it is more than 300° C., there is a problem in that the surface of the particles is arbitrarily oxidized due to high temperature.

The ultrasonic treatment causes typical physical phenomena such as fluid cavitation, local heating, and free radical formation. Fluid cavitation can induce the dispersion and functional groups of non-oxide ceramic particles by the generation of bubbles and the force caused by the explosion. In addition, local heating occurs due to high energy supply, and impurities strongly adsorbed on the surface of particles can be effectively removed by forming free radicals.

The ultrasonic treatment may be performed for 10 to 150 minutes, preferably, 20 to 70 minutes. If the ultrasonic treatment time is less than 10 minutes, it is difficult to remove impurities from the surface of the particles or modify the surface of the particles, and if it exceeds 150 minutes, the surface of the particles may be damaged.

The milling treatment may be performed by a wet method, a dry method, or a combination of wet and dry methods. Through the milling process, the average particle size of the particles can be made uniform, and the reactivity of the particle surface can be increased by surface friction between the particles.

The bonding relationship of two or more of the metal particles, the non-oxide ceramic particles, and the oxide ceramic particles may be exemplified as follows, but is not limited thereto.

First, the non-oxide ceramic particles surface-treated to have a charge opposite to that of the metal particles may be coupled to each other by electrostatic attraction. When metal particles with excellent electrical conductivity and non-oxide ceramic particles are combined, electrical conductivity can be maximized.

In addition, oxide ceramic particles surface-treated to have an opposite charge to composite particles made of metal particles and non-oxide ceramic particles may be coupled to each other by electrostatic attraction. When composite particles with excellent electrical conductivity and oxide ceramic particles with insulating properties are used simultaneously, an electric conductive path can be induced. That is, when the composite particles and the oxide ceramic particles are uniformly dispersed without agglomeration on the surface of the substrate, or the oxide ceramic particles are electrostatically attached to the composite particles and uniformly distributed on the substrate to closely adhere and apply the current is guided to the composite particles without passing through the oxide ceramic particles.

In addition, oxide ceramic particles having insulating properties also generate some electrical conduction paths that can receive and move electrons from the metal particles and/or the non-oxide ceramic particles bonded by electrostatic attraction due to the change in the energy barrier through surface treatment. can do.

Conversely, the oxide ceramic particles surface-treated to have the same electric charge as the composite particles may be co-dispersed from each other by electrostatic repulsion.

The non-oxide ceramic particles may further include one selected from the group consisting of carbon black, graphene, carbon nanotubes, fullerenes, Mxenes, and combinations of two or more thereof, but is not limited thereto. The maxon is a two-dimensional transition metal carbide in which a carbide, two carbon atoms, and other metal atoms are combined. In general, metal particles are used as conductive materials such as electromagnetic shielding, but there are disadvantages in that the density of metal particles is large and heavy, and corrosion by acid, air, moisture, salt water, etc. easily occurs. The non-oxide ceramic particles have a lower thermal conductivity or electrical conductivity than metals, but have an advantage in that they are more durable in an external environment. Therefore, the non-oxide ceramic particles may be used at the same time to realize a synergistic effect of durability, electrical and thermal conductivity of the metal particles, and excellent electrical conductivity of the carbon-based conductive material.

The average particle size of the metal particles, the non-oxide ceramic particles, and the oxide ceramic particles may be 1 to 200,000 nm, preferably, 50 to 20,000 nm, but is not limited thereto. If the average particle size of the metal particles, the non-oxide ceramic particles, and the oxide ceramic particles is less than 1 nm, it is difficult to produce nanometer-sized particles, and if it exceeds 200,000 nm, the surface area of the particles becomes small, so that electrical conductivity, thermal conductivity and inter-particle The bonding strength may be reduced.

Each of the particles is a rod, spherical, square, flake, layered structure, hollow, mesoporous, and a group consisting of a combination of two or more thereof. It may be one selected from, preferably, it may be a sphere, but is not limited thereto.

The particles may further include shapes such as irregular stars, trapezoids, and octahedrons. In addition, the shape of the particles is not limited to those exemplified above, and other rods, spheres, squares, and flakes are combined with each other or one of them is partially modified, for example, a hemisphere, It may be understood to include an ellipsoid, a hollow body, a rectangle, a trapezoid, a rhombus, a parallelogram, and the like.

The ceramic composition may further include one binder resin selected from the group consisting of organic binders, inorganic binders, cationic polymers, anionic polymers, nonionic polymers, amphiphilic polymers, and combinations of two or more thereof.

Polymers have low electrical conductivity and high electrical resistance, so it is difficult to expect the role of conductive polymers used for electromagnetic shielding, and only serves as a liquid solvent or vehicle. However, when the surface charges of the particles are the same, the positive or negatively charged resin can help the dispersion stability of the particles and the electrical adsorption to the substrate to be attached, and due to the combination of the particles and the resin, A conductive path may be formed.

In the ceramic composition, two or more of the metal particles, the non-oxide ceramic particles, and the oxide ceramic particles are heterogeneous particles applied at the same time, so it is important to increase their dispersibility. If the dispersibility of the heterogeneous particles is poor, that is, if they exist arbitrarily agglomerated, the flow of electricity is disturbed, and an electric field is locally concentrated, resulting in an overcurrent phenomenon, resulting in increased resistance. In contrast, by surface-treating at least two of the metal particles, the non-oxide ceramic particles, and the oxide ceramic particles, respectively, affinity with the binder resin can be improved to increase dispersibility. In addition, it is possible to prevent a problem of a decrease in dispersibility due to the combination of particles and resin, and it is possible to improve conductivity by increasing the conductive path by removing the impediment to the current.

Meanwhile, the ceramic composition may further include one selected from the group consisting of pigments, dyes, curing agents, charge control agents, electrolytes, dispersants, clays, and combinations of two or more thereof. In particular, by further including a pigment in the ceramic composition, the ceramic composition can be used as a paint, ink, paint, paste, etc. having various colors.

The ceramic composition includes dip coating, spray coating, roll coating, bar coating, and a brush on the surface of a metal substrate made of ferrous metal, non-ferrous metal, etc. Coating (brush coating), vapor deposition, sputtering, electrospinning, and a method selected from the group consisting of a combination of two or more thereof may be continuously wet-coated two or more times.

Manufactured by adjusting the weight or volume ratio of the solvent and the ceramic composition in any one of a slurry, a paste, a gel, or a film to apply the ceramic composition to the surface of a metal substrate can do.

The substrate may be one selected from the group consisting of aluminum, iron, magnesium, titanium, special stainless steel, and combinations of two or more thereof, but is not limited thereto.

The wet coating may be performed by applying a predetermined voltage between the metal substrate and the ceramic composition. For example, the wet coating may be made by electrodeposition coating. During electrodeposition coating, a voltage of 0 to 100V may be applied between the metal substrate and the ceramic composition, preferably, a voltage of 10 to 50V, more preferably, a voltage of 12 to 50V may be applied, but limited thereto it's not going to be When the applied voltage is less than 10V, coating of the ceramic composition does not occur smoothly on the substrate, and when it exceeds 100V, the thickness of the coated coating film may become thick due to the high voltage.

The wet coating of the ceramic composition may be continuously performed two or more times. As used herein, the term "wet coating" refers to coating a liquid ceramic composition twice or more to form a multi-layered coating film, continuously coating the ceramic composition for forming an upper coating film before the lower coating film is dried. means the way

As described above, through the wet coating performed two or more times in succession, the adhesion, adhesion, and paintability between the coating film and the coating film can be improved, and the surface resistance can be precisely controlled through a simple and economical process.

Specifically, the surface resistance is uniformly implemented in the entire area of the coating film having a multilayer structure, for example, the entire area, and the variable characteristics of the surface resistance according to the number of coatings and/or the thickness of the coating film are within a predictable range. In order to precisely control it, adhesion, miscibility, and homogeneity at the interlayer interface constituting the coating layer must be sufficiently implemented.

In forming a multi-layered coating film by coating the liquid ceramic composition two or more times, the ceramic composition for forming the upper coating film is continuously coated before the lower coating film is dried, and then the lower and upper coating films are dried simultaneously to form a coating film. Adhesion, miscibility, and homogeneity at the interlayer interface can be sufficiently implemented. In addition, it is possible to precisely control the variable characteristics of the surface resistance within a predictable range by solving problems such as discontinuous change or rapid increase of the surface resistance at the interface, resulting in substantial insulation.

In addition, the composition of the ceramic composition for forming the lower and upper coating films may be the same or different, and preferably, the lower and upper coating films are formed using a ceramic composition having the same composition in consideration of adhesion and miscibility between the coating films. can do.

As described above, the ceramic composition wet coated two or more times can be washed and dried to form a coating film having a predetermined surface resistance.

The washing step may be performed to remove the plating solution adhered to the surface of the substrate after the electrodeposition coating. As the washing water, one selected from the group consisting of distilled water, ethanol, methanol, soft water, and a combination of two or more thereof may be used, and preferably distilled water or ethanol may be used, but is not limited thereto.

The drying step may be dried for 0.1 to 24 hours at a temperature of 60 ~ 200 ℃ using a drying furnace. If the temperature of the drying furnace is less than 60° C., the solvent used for washing water may not be smoothly removed, and if it exceeds 200° C., the applied ceramic composition may be oxidized and damaged. In addition, if the drying time is less than 0.1 hours, sufficient time is not given to remove the solvent used as washing water, and if it exceeds 24 hours, energy efficiency may be reduced.

In addition, the drying step may be subdivided into a washing water removal step for removing the solvent used as the washing water, and a heat replacement or heat treatment step for increasing the strength of the coating film by raising the temperature of the drying furnace to 150° C. or higher. The reinforced coating film may have a higher bonding strength with the substrate, and thus durability may be enhanced.

Hereinafter, embodiments of the present invention will be described in detail.

1. Preparation of surface treatment composition

Production Examples 1 to 8

Silica nanoparticles having a surface modified with 3-aminopropyl groups (Sigma-Aldrich, SiO ₂ -NH ₂ ), silica nanoparticles having a surface modified with 3-carboxypropyl groups (Sigma-Aldrich, SiO ₂ -COOH), sodium silicate ( Na ₂ SiO ₃ ), sodium lauric sulfate (SLS), and ethylene diamine tetra acetic acid (EDTA) were mixed with water at the ratios or concentrations shown in Table 1 below to prepare a surface treatment composition.

ingredient Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 SiO ₂ -NH ₂ 10 15 20 5 5 SiO ₂ -COOH 10 15 20 5 10 Na ₂ SiO ₃ 25 25 25 25 25 25 25 25 SLS 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 EDTA One One One One One One One One water 63.5 58.5 53.5 63.5 58.5 53.5 63.5 58.5

(Unit: % by weight)

Comparative Preparation Examples 1 to 8

Sodium hydroxide (NaOH), sodium silicate (Na ₂ SiO ₃ ), and sodium lauric sulfate (SLS) were mixed with water at the ratios or concentrations shown in Table 2 below to prepare a surface treatment composition.

ingredient comparison
Preparation Example 1 comparison
Preparation 2 comparison
Preparation 3 comparison
Preparation 4 comparison
Preparation 5 comparison
Preparation 6 comparison
Preparation 7 comparison
Preparation 8 NaOH 30 30 30 30 30 30 30 30 Na ₂ SiO 3 0.1 One 2 3 SLS 2 4 6 8 6 6 6 6

(Unit: g/L)

Experimental Example 1

Aluminum specimens (6cm × 3cm) and iron specimens (6cm × 3cm) were washed with ultrasonic waves for 10 minutes and dried, and machine oil and vegetable oil used in the pressing process were uniformly applied to the aluminum and iron specimens and dried, then aluminum Specimens and iron specimens were placed in 500 mL of the prepared surface treatment composition and immersed at a temperature of 40 to 50° C. for 30 to 40 minutes.

The degreasing temperature was set at 50° C., and after degreasing for 40 minutes, the degreasing performance was evaluated through the degreasing ratio calculated by the following formula, and the results are shown in Table 3, FIGS. 2 and 3 below.

<expression>

Degreasing rate (%) = {(Amount of oil removed, g)/(Amount of oil applied, g)} * 100

division Degreasing rate (aluminum specimen) Degreasing rate (iron specimen) Preparation Example 1 93.0 99.3 Preparation 2 93.1 99.4 Preparation 3 93.2 99.5 Preparation 4 92.8 99.1 Preparation 5 93.1 99.4 Preparation 6 93.3 99.6 Preparation 7 93.3 99.6 Preparation 8 93.5 99.8 Comparative Preparation Example 1 72.8 78 Comparative Preparation Example 2 73.8 79 Comparative Preparation Example 3 74.7 80 Comparative Preparation Example 4 74.7 80 Comparative Preparation Example 5 83.3 89 Comparative Preparation Example 6 84.2 90 Comparative Preparation Example 7 85.2 91 Comparative Preparation Example 8 85.6 91.5

2. Preparation of conductive ceramic composition

Preparation 9

(1) Surface treatment of metal particles

Add 3 g of Sn particles and 100 ml of distilled water to a 1L round-bottom flask and stir at a speed of 300 rpm using a stirrer. While maintaining stirring, titrate the pH of the solution to 4.2 or less using 1N HCl and a pH meter. After raising the heating mantle to 90° C., heat treatment is performed while maintaining stirring for 1 hour. Then, surface-treated Sn particles are recovered using a centrifuge at 30,000 rpm for 10 minutes to remove the reaction filtrate, and then redispersed in 50 ml of propylene carbonate solution.

(2) Surface treatment of non-oxide ceramic particles

10 g of SiC particles and 100 ml of distilled water are placed in a 1L round-bottom flask, and the solution is prepared by ultrasonication. While stirring the solution at a speed of 300 rpm, the pH of the solution is titrated to 8 using 1N NH 4 OH and a pH meter. After that, stirring is maintained at room temperature for 1 hour. To remove the reaction filtrate, the surface-treated SiC particles are recovered using a centrifuge at 30,000 rpm for 10 minutes, and then redispersed in 50 ml of propylene carbonate solution.

(3) conductive ceramic composition

The solution obtained in step (2) is added to the solution obtained in step (1). Thereafter, 100 ml of a solution in which 1 g of SiO ₂ is dissolved in propylene carbonate is added and then dispersed through sonication at 90° C. for 2 hours.

Preparation 10

A conductive ceramic composition was prepared in the same manner as in Example 1, except that ZrB ₂ was used instead of SiC in step (2) of Preparation Example 9.

Preparation 11

(1) Surface treatment of non-oxide ceramic particles

Put 10 g of SiC powder and 100 ml of distilled water in a 1L round-bottom flask, and stir at a speed of 300 rpm using a stirrer. While maintaining stirring, titrate the pH of the solution to 3 using 1N HCl and a pH meter. After raising the heating mantle to 80° C., heat treatment is performed while maintaining stirring for 1 hour. Thereafter, the surface-treated non-oxide ceramic particles are recovered using a centrifuge at 30,000 rpm for 10 minutes to remove the reaction filtrate. Then, the particles are redispersed in 50ml epoxy solution.

(2) Surface treatment of oxide ceramic particles

In a 1L round-bottom flask, 3 g of SiO ₂ powder and 100 ml of distilled water were placed and sonicated to prepare a solution. While stirring the solution at a speed of 300 rpm, the pH of the solution is titrated to 8.5 using 1N NH ₄ OH and a pH meter. Thereafter, stirring is maintained at room temperature for 1 hour. To remove the reaction filtrate, the surface-treated oxide ceramic particles are recovered using a centrifuge at 30,000 rpm for 10 minutes. The particles are then redispersed in 50ml epoxy solution.

(3) conductive ceramic composition

The solution obtained in step (2) is added to the solution obtained in step (1). After adding 100 ml of an epoxy binder solution and a curing agent, it is dispersed through ultrasonication at room temperature for 2 hours.

Preparation 12

A conductive ceramic composition was obtained in the same manner as in Preparation Example 11, except that an acrylic binder solution was used instead of the epoxy binder solution in step (3) of Preparation Example 11.

Preparation 13

A conductive ceramic composition was obtained in the same manner as in Preparation Example 11, except that the pH of the solution was adjusted to 10 using NH ₄ OH in step (1) of Preparation Example 11.

Preparation 14

(1) Surface treatment of non-oxide ceramic particles

Put 10 g of SiC powder and 100 ml of distilled water in a 1L round-bottom flask, and stir at a speed of 300 rpm using a stirrer. While maintaining stirring, titrate the pH of the solution to 3 using 1N HCl and a pH meter. After raising the heating mantle to 80° C., heat treatment is performed while maintaining stirring for 1 hour. Thereafter, the surface-treated non-oxide ceramic particles are recovered using a centrifuge at 30,000 rpm for 10 minutes to remove the reaction filtrate. Then, the particles are redispersed in 50ml epoxy solution.

(2) Surface treatment of oxide ceramic particles

In a 1L round-bottom flask, 3 g of SiO ₂ powder and 100 ml of distilled water were placed and sonicated to prepare a solution. After stirring at 300 rpm for 30 minutes at room temperature, 5 ml of aminopropyltrimethoxysilane is slowly added. Keep stirring at room temperature for 3 hours. To remove the reaction filtrate, the surface-treated oxide ceramic particles are recovered using a centrifuge at 30,000 rpm for 10 minutes. The particles are then redispersed in 50ml epoxy solution.

(3) conductive ceramic composition

The solution obtained in step (2) is added to the solution obtained in step (1). Thereafter, 100 ml of an acrylic binder solution and a curing agent are added, and then dispersed through ultrasonication at room temperature for 2 hours.

Comparative Preparation Example 9

(1) Preparation of non-oxide ceramic particles

Add 50ml epoxy solution to 10g of SiC particles and disperse ultrasonically.

(2) Preparation of oxide ceramic particles

Add 50ml epoxy solution to 3g of SiO ₂ particles and disperse ultrasonically.

(3) ceramic composition

The solution obtained in step (2) is added to the solution obtained in step (1). After adding 100 ml of epoxy solution, it is dispersed through sonication at room temperature for 2 hours.

The charges of the metal particles, non-oxide ceramic particles, oxide ceramic particles, and binder resins used in Preparation Examples 9 to 14 and Comparative Preparation Example 9 are summarized in Table 4 below.

division metal particles Non-Oxide Ceramic Particles oxide ceramic particles binder resin Preparation 9 + - X X Preparation 10 + - X X Preparation 11 X + - + Preparation 12 X + - - Preparation 13 X - - + Preparation 14 X - + - Comparative Preparation Example 9 X X X +

+ : (+) charge, - : (-) charge, X : no charge/not applicable

5 is a SEM image of the conductive ceramic composition prepared in Preparation Example 9. Referring to FIG. 5 , it can be confirmed that the SiC particles are electrostatically bonded to the surface of the Sn particles.

6 is an EDX mapping image of the conductive ceramic composition prepared in Preparation Example 9, and FIG. 7 is a TEM image of the conductive ceramic composition prepared in Preparation Example 9. 6 and 7 , both Sn particles and SiC particles were observed in the conductive ceramic composition, and in particular, it can be seen that SiC particles are present on the surface of the Sn particles as a whole.

Also, FIG. 8 is an SEM and EDX mapping image of the conductive ceramic composition prepared in Preparation Example 11. Referring to FIG. Referring to FIG. 8, it can be seen that oxide ceramic particles (B) are electrostatically bonded to non-oxide ceramic particles (A) (FIG. 8(a)), and oxide ceramic particles are generally distributed on non-oxide ceramic particles. It can be confirmed (FIGS. 8(b) and 8(c)).

9 is an average particle size measurement result of the conductive ceramic composition prepared in Preparation Example 9 and Comparative Preparation Example 9. Referring to FIG. 9 , in Comparative Preparation Example 9, three peaks are separated, which is determined because non-oxide ceramic particles and oxide ceramic particles are electrostatically bonded or co-dispersed and do not exist. That is, the non-oxide ceramic particle peak, the oxide ceramic particle peak, and other peaks having a large particle size are formed due to aggregation of the particles and are present. On the other hand, in the case of Preparation Example 9, it can be confirmed that the non-oxide ceramic particles and the oxide particles having different charges do not agglomerate between the particles even in an electrostatically bonded state, so that a single peak appears.

3. Electrodeposition coating

Examples and Comparative Examples

(1) cleaning of the substrate

The base material of the aluminum composition was placed in a container on which the surface treatment composition prepared according to Preparation Example 1 was supported, and ultrasonic waves were applied to degrease and wash for 1 minute.

(2) Primary coating of conductive ceramic composition

The aluminum substrate was dip-coated with the conductive ceramic composition prepared according to Preparation Examples 9 to 14 and Comparative Preparation Example 9, respectively. During the process, the conductive ceramic composition was mechanically stirred at a speed of 300 rpm, and a (+) charge was applied to the aluminum substrate and a (-) charge was applied to the conductive ceramic composition. At this time, the applied voltage was 12.5V, and was performed for 15 seconds.

(3) Secondary coating of conductive ceramic composition

The aluminum substrate coated with the primary as described above was dip-coated with the conductive ceramic composition prepared according to Preparation Examples 9 to 14 and Comparative Preparation Example 9, respectively. During the process, the conductive ceramic composition was mechanically stirred at a speed of 300 rpm, and a (+) charge was applied to the aluminum substrate and a (-) charge was applied to the conductive ceramic composition. At this time, the applied voltage was 12.5V, and was performed for 15 seconds.

(4) washing step

After the electrodeposition coating was completed, it was washed twice with distilled water to remove the residual conductive ceramic composition and other foreign substances on the surface of the substrate. Up to now, all processes have been performed at room temperature.

(5) drying step

The washed aluminum substrate was dried at 120° C. for 30 minutes to remove all washing water on the surface, and then the temperature was raised to 180° C. and dried for 1 hour.

Table 5 below shows the surface resistance of the conductive ceramic composition (coating solution) used for the primary and secondary coatings and the finally obtained coating film.

division primary coating secondary coating coating solution Surface resistance (mΩ) coating solution Surface resistance (mΩ) Example 1 Preparation 9 0.017 Preparation 9 0.021 Example 2 Preparation 10 0.042 Preparation 10 0.062 Example 3 Preparation 11 0.007 Preparation 11 0.025 Example 4 Preparation 12 0.064 Preparation 12 0.081 Example 5 Preparation 13 0.039 Preparation 13 0.057 Example 6 Preparation 14 0.059 Preparation 14 0.076 Example 7 Preparation 9 0.017 Preparation 10 0.037 Example 8 Preparation 9 0.017 Preparation 11 0.038 Example 9 Preparation 9 0.017 Preparation 12 0.041 Example 10 Preparation 9 0.017 Preparation 13 0.043 Example 11 Preparation 9 0.017 Preparation 14 0.035 Comparative Example 1 Comparative Preparation Example 9 0.22 Comparative Preparation Example 9 0.31 Comparative Example 2 Preparation 9 0.017 Preparation 9
(Coating after complete drying of the first coating) 0.28

The description of the present invention described above is for illustration, and those of ordinary skill in the art to which the present invention pertains can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a dispersed form, and likewise components described as distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention.

Claims (10)

(a) degreasing and washing the surface of the metal substrate with a surface treatment composition having a pH-dependent variable charge, the first material having a terminal or surface modified with a hydrophilic or hydrophobic functional group, an inorganic salt, and a surfactant; and
(b) a ceramic comprising a second material electrostatically bonded or co-dispersed to each other by surface treatment such that at least two of the metal particles, the non-oxide ceramic particles, and the oxide ceramic particles have a positive or negative charge Containing, coating method comprising a; after continuously wet coating the composition on the surface of the metal substrate two or more times, and then drying. According to claim 1,
The first material is one selected from the group consisting of a zero valent metal, a metal salt, a ceramic compound, an ionic polymer, and a combination of two or more thereof. According to claim 1,
The content of the first material in the surface treatment composition is 5 to 50% by weight, the coating method. delete According to claim 1,
The content of the inorganic salt in the surface treatment composition is 5 to 50% by weight, the coating method. According to claim 1,
The metal particles are Li, Be, Na, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Cs, Ba, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, Po, At, Fr, Ra, Ac, Th, Pa, U, Np, Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No, Lr, Rf, Db, Sg, Bh, Hs, and one selected from the group consisting of combinations of two or more thereof, the coating method. According to claim 1,
The non-oxide ceramic particles include one selected from the group consisting of Si, B, C, S, P, N, and combinations of two or more thereof. According to claim 1,
The oxide ceramic particles include a metal component and O, the coating method. According to claim 1,
The ceramic composition further comprises one binder resin selected from the group consisting of organic binders, inorganic binders, cationic polymers, anionic polymers, nonionic polymers, amphiphilic polymers, and combinations of two or more thereof. According to claim 1,
The wet coating is made by applying a predetermined voltage between the metal substrate and the ceramic composition, the coating method.

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