KR101107235B1 - Light-color magnetic particle using organic material and method for preparing the same - Google Patents

Abstract

The present invention relates to light colored magnetic particles using organic materials and a method of manufacturing the same, and more particularly, to form magnetic particles by mixing and stirring melamine-formaldehyde resin, a surfactant, and magnetic particles; And separating the coated magnetic particles using a magnet from the coated magnetic particles. The present invention relates to a method of preparing light colored magnetic particles using an organic material, and to magnetic particles prepared by the method.

In the method of manufacturing light-colored magnetic particles using the organic material of the present invention, by coating a white melamine-formaldehyde resin on the surface of each of the magnetic particles, the color of the particles can be efficiently made light with a small amount of coating material. Rather, it prevents agglomeration of the magnetic particles so that the particles can be easily dispersed in the solution. In addition, the manufacturing method of the present invention controls the coating thickness by controlling the number of coating of the magnetic particles, thereby allowing to control the magnetic properties and color of the particles.

Magnetic Particles, Melamine, Formaldehyde, Surfactant, Coating

Description

Light-color magnetic particle using organic material and method for preparing the same}

The present invention relates to light colored magnetic particles using organic materials and a method of manufacturing the same, and more particularly, to form magnetic particles by mixing and stirring melamine-formaldehyde resin, a surfactant, and magnetic particles; And separating the coated magnetic particles using a magnet from the coated magnetic particles. The present invention relates to a method of preparing light colored magnetic particles using an organic material, and to magnetic particles prepared by the method.

Banknotes currently on the market contain various anti-counterfeiting devices such as holograms, color conversion inks, latent images, and hidden wires. Recently, however, more and more cases of forgery of money have been relatively precisely difficult to distinguish with the naked eye. In order to prevent this, forgery is impossible, and forgery prevention device using magnetic material has been in the spotlight as a technology that can easily detect forgery.

In general, metals used as magnetic materials have advantages of semi-permanent magnetic properties and strong magnetic properties even in small amounts. In addition, since the particle size can be manufactured at the nano level, a small amount of particles can be mixed with the ink to be used as an anti-counterfeiting ink. However, most of the existing magnetic particles such as Ni, Fe, Fe ₃ O ₄ have a very dark specific color, and it is difficult to make various colors, and even after dispersing in the ink solution for some time, agglomeration between the particles occurs and uniformity occurs. There is a limit to producing ink of quality. Therefore, the development of new magnetic particles that overcome the above disadvantages is urgent.

Melamine is a heterocyclic amine, an organic base and a trimer of cyanamide, consisting of 66% of its mass by nitrogen and resistant to fire when mixed with resin. Chemical number CAS 108-78-1, also known as 2,4,6-triamino-1,3,5-triazine or cyanurotriamide. The formula C ₃ H ₆ N _6, molecular weight of the rod-shaped 126.12 colorless crystals, melting point 347 (decomposition), specific gravity 1.573 (14), a sublimable. It is soluble in hot water to some extent, but insoluble in cold or ethanol, and insoluble in ether. Melamine is produced by reacting dicyandiamide with liquid ammonia under pressure. When heated together with formalin, it becomes a melamine resin by a condensation reaction.

Formaldehyde is a gas obtained by oxidizing methanol. It has a pungent odor, a strong reducibility, and when oxidized, it becomes formic acid. It is particularly well soluble in water to form a 40% aqueous solution, which is commercially available formalin and is used to fix tissue sections of living bodies. It is also called methylaldehyde, methanal, and has the formula HCHO, molecular weight 30.0, melting point -92, boiling point -21, specific gravity 0.815. It is highly reducible and can be easily detected by reducing the pelling solution or the silver ammonium solution. Oxidation results in formic acid (HCOOH). Formaldehyde readily polymerizes to give trioxymethylene (metaformaldehyde), but when heated it is regenerated into formaldehyde. Reacts with phenol, uric acid, etc. to make resins, and also exhibits common properties as aldehydes. It dissolves well in water and is generally made into a 40% aqueous solution, which is commercially available as formline.

Surfactants are substances that adsorb to the interface in dilute solutions to reduce their surface tension. Usually, both lipophilic and lipophilic groups that contain both lipophilic and hydrophilic groups in one molecule can be surfactants. It is also called a surfactant, and soap is a representative one, and the surface tension of soapy water is much smaller than that of water. This is known to be due to the fact that soap collects on the surface of water and tries to make the surface as wide as possible. Soap is well collected on the surface of water because it contains lipophilic groups such as long chain alkyl groups and hydrophilic groups such as carboxy groups in the molecules of soap (e.g. sodium stearate). The lipophilic group is formed by the reaction of water to the surface.

Anionic surfactants are ionized in an aqueous solution of the surfactant and become anions. Soaps, alkylbenzenesulfonates, and the like are included in this. In addition, cationic surfactants are ionized to be cations, and higher amine halides, quaternary ammonium salts, alkylpyridinium salts, and the like fall into this category. In addition, both are called amphoteric surfactants, and amino acids etc. belong to this. On the other hand, what is not ionized can also be distinguished as a nonionic surfactant, but polyethyleneglycol etc. belong to this. Surfactants generally have washing power, emulsifying power, dispersing power, osmotic power, foaming power, etc., and according to their characteristics, detergents, fiber treatment agents, emulsifiers, flotation agents, It is widely used as a foaming agent, a lubricant additive, a disinfectant, and a paint dispersant for cement.

In order to solve the above problems, the present invention is to provide a method for producing a light-colored magnetic particles by coating the nano-sized metal particles with a white organic material, and to provide a magnetic particles produced by the method.

In order to solve the above problems, the present invention comprises the steps of mixing and stirring the melamine-formaldehyde resin and the surfactant, and the magnetic particles to coat the magnetic particles; And separating the coated magnetic particles using a magnet from the coated magnetic particles. The method provides a light-colored magnetic particle using an organic material, and a magnetic particle manufactured by the method.

In the method of manufacturing light-colored magnetic particles using the organic material of the present invention, by coating a white melamine-formaldehyde resin on the surface of each of the magnetic particles, the color of the particles can be efficiently made light with a small amount of coating material. Rather, it prevents agglomeration of the magnetic particles so that the particles can be easily dispersed in the solution. In addition, the manufacturing method of the present invention controls the coating thickness by controlling the number of coating of the magnetic particles, thereby allowing to control the magnetic properties and color of the particles.

The present invention comprises the steps of mixing and stirring the melamine-formaldehyde resin, the surfactant, and the magnetic particles to coat the magnetic particles; And separating the coated magnetic particles by using a magnet.

In the present invention, the melamine-formaldehyde resin may be prepared by mixing the melamine and formaldehyde aqueous solution, and then heating.

In the present invention, the surfactant may be any one selected from the group consisting of pluronic F68, Pluronic F127, Pluronic P105 and Pluronic L44.

In the present invention, the magnetic particles may be a mixture of one or two or more nanoparticles selected from the group consisting of iron, iron oxide, nickel, nickel oxide, cobalt, nickel-cobalt, iron-cobalt and chromium oxide.

In addition, the manufacturing method of the present invention may further include the step of repeatedly coating the coated magnetic particles after the step of obtaining the coated magnetic particles.

In addition, in the manufacturing method of the present invention, the coating may be repeatedly coated three to four times.

Hereinafter, a method of manufacturing light-colored magnetic particles using the organic material of the present invention will be described in more detail.

The present invention relates to a method for producing light-colored magnetic particles using an organic material, and after mixing melamine and formaldehyde aqueous solution, heating to prepare a melamine-formaldehyde resin, the melamine-formaldehyde resin and surfactant And mixing and stirring the magnetic particles to coat the magnetic particles, and separating the coated magnetic particles using a magnet.

In the present invention, a melamine formaldehyde resin was used as a material surrounding the magnetic particles. Melamine-formaldehyde resin is a white thermosetting resin and is known to be excellent in mechanical strength, heat resistance and solvent resistance. In recent years, melamine-formaldehyde resins and surfactants can be used to synthesize porous microspheres of several micrometers in size, so that magnetic particles can be wrapped with melamine-formaldehyde resins to produce relatively thin coating thicknesses. Not only can the original color of the magnetic particles be concealed, but also excellent in heat resistance and solvent resistance, it can be applied to inks of various solvents and is expected to have advantages such as no deformation of properties even in a high temperature printing process.

In addition, in order to achieve the above object, the thickness of the organic material surrounding the magnetic particles should be at least 300 nm, and in order to make the coating thickness 300 nm or more, the coating is repeated several times.

In the method of manufacturing light-colored magnetic particles using the organic material of the present invention, white melamine-formaldehyde resin is coated on the surface of each magnetic particle to efficiently lighten the color of the particles with a small amount of coating material. Rather, it prevents agglomeration of the magnetic particles so that the particles can be easily dispersed in the solution. In addition, the coating thickness is controlled by adjusting the number of coatings of the magnetic particles, and through this, the magnetic properties and the color of the particles may be controlled.

In the present invention, after mixing the melamine and formaldehyde aqueous solution, and heated to prepare a melamine-formaldehyde resin, the melamine-formaldehyde resin and the surfactant, and the magnetic particles are mixed and heated while stirring to coat the coated magnetic particles Manufacture. The above-described coated magnetic particles are repeated a number of times and the coating thickness of the surface of the magnetic particles is adjusted to adjust magnetic properties and colors of the particles. In addition to the melamine-formaldehyde resin, a resin such as polyamide, polyimide, polyester, polystyrene, or the like may also be used.

The surfactant can be selected from the group consisting of Pluronic F68, Pluronic F127, Pluronic P105 and Pluronic L44.

The magnetic particles are characterized by consisting of iron, iron oxide, nickel, nickel oxide, cobalt, nickel-cobalt, iron-cobalt, chromium oxide and mixtures of two or more thereof.

In addition, the manufacturing method of the light-colored magnetic particles using the organic material of the present invention is characterized by controlling the magnetic properties and color of the particles by controlling the thickness of the organic material on the surface of the magnetic particles by repeating the above coating process several times. do.

Hereinafter, embodiments of the present invention will be described. The following examples are intended to illustrate the present invention in more detail, and the scope of the present invention is not intended to be limited thereto.

<Example 1> Preparation of magnetic particles having a pale color using an organic material

Production of pale color magnetic particles using the organic material of the present invention was carried out as follows (see Fig. 1).

10.09g melamine, 17.84ml formaldehyde, 0.4ml 1M NaOH aqueous solution, 8g pluronic F-127, 200ml water, 5g iron nanoparticles (Fe nanoparticle, 0.5 ~ 0.5) was added to the flask and heated with stirring with a mechanical stirrer at 100 ° C. for 12 hours. After the reaction was completed for 12 hours, the reacted solution was cooled to room temperature. Magnets were used to filter coated particles out of solution, wash with water, and then dry.

In order to control the coating thickness of the coated particles, the above process was repeated by putting the coated particles back into the solution under the above conditions. In this way, the magnetic particles coated several times have a color close to white as the number of coatings increases, and the magnetic properties are lowered. The number of coatings is preferably performed in the range of 1 to 6 times, preferably 3 to 4 times.

[Table 1] Average thickness and deviation of the coating according to the number of coating

Number of coatings 1 time Episode 2 3rd time 4 times Thickness of coating 0.376 ± 0.33 1.435 ± 0.39 2.811 ± 0.36 3.341 ± 0.40

As described above, when the number of times is one, the deviation value (0.33) is larger than the average thickness (0.376), so that the coating is very uneven. On the third and fourth times (2.811) and four times (3.341), the average thickness is 6-8. Although the thickness is much thicker than twice, each deviation value is not significantly different (3 times 0.36, 4 times 0.40), so that the particles coated three times and four times are coated more uniformly than the one time. .

A TEM photograph of the magnetic particles having the number of coating times described above is shown in FIG. 2A, and a TEM photograph of the magnetic particles having three times of coating times is shown in FIG. 2B. As can be seen in the photograph of FIG. 2, as the number of coatings increases, the coating thickness becomes thick and the coating is uniform.

3 is an EDS analysis result of the magnetic particle surface (upper part of FIG. 3) and the inside (lower part of FIG. 3) of FIG. As shown in FIG. 3, the surface of the particles is mostly composed of C, and the interior of the particles is composed of Fe. As a result, it was found that the surface of the magnetic particles was coated with melamine-formaldehyde resin.

<Example 2-5> Preparation of light colored magnetic particles using an organic material

Magnetic particles were prepared in the same manner as in Example 1, but were prepared by varying the type of magnetic particles (see Table 1 below).

[Table 1]

division Magnetic particles used Example 2 nickel Example 3 Nickel-cobalt Example 4 Iron-cobalt Example 5 Chromium oxide

<Example 6-8> Preparation of light colored magnetic particles using organic materials

Magnetic particles were prepared in the same manner as in Example 1, but were prepared by different kinds of surfactants (see Table 2 below).

TABLE 2

division Used surfactant Example 6 Pluronic F68 Example 7 Pluronic P105 Example 8 Pluronic L44

Example 9-12 Preparation of Pale-colored Magnetic Particles Using Organic Materials

Magnetic particles were prepared in the same manner as in Example 1, except that the resin of Table 3 was used instead of the melamine-formaldehyde resin (see Table 3 below).

[Table 3]

division Used resin Example 9 Polyamide Example 10 Polyimide Example 11 Polyester Example 12 Polystyrene

The present invention has been described above in connection with specific embodiments of the present invention, but this is only an example and the present invention is not limited thereto. Those skilled in the art can change or modify the described embodiments without departing from the scope of the present invention, and such changes or modifications also fall within the scope of the present invention.

In addition, the materials of each component described herein can be readily selected and substituted for various materials known to those skilled in the art. Those skilled in the art will also appreciate that some of the components described herein can be omitted without degrading performance or adding components to improve performance. In addition, those skilled in the art may change the order of the method steps described herein depending on the process environment or equipment. Therefore, the scope of the present invention should be determined by the appended claims and equivalents thereof, not by the embodiments described.

Magnetic particles produced by the manufacturing method of the present invention is applicable to the hologram of the banknote, etc., and can be produced by a more economical and efficient manufacturing method is expected to contribute to the industrial development of the related field and the industrial development of the country.

Figure 1 schematically shows a process for producing a pale color magnetic particles using the organic material of the present invention.

Figure 2 (a) and (b) is a TEM photograph of the magnetic particles coated by the method of Example 1, (a) is a magnetic particle having one coating number, (b) is a magnetic number of three coatings The particles are shown.

Figure 3 shows the results of EDS analysis on the surface (top 3) and inside (bottom 3) of the magnetic particles shown in Figure 2 (a).

Claims (6)

delete delete Coating the magnetic particles by mixing and stirring the melamine-formaldehyde resin, the surfactant, and the magnetic particles; And separating the coated magnetic particles by using a magnet. In the method of manufacturing light-colored magnetic particles using an organic material, the surfactants include pluronic F68, pluronic F127, A method for producing light colored magnetic particles using an organic material, characterized in that any one selected from the group consisting of Pluronic P105 and Pluronic L44. delete delete delete

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