KR102553133B1 - Apparatus and method for manufacturing iron oxide - Google Patents

Abstract

The present invention relates to an iron oxide coating apparatus and method capable of easily adjusting the type and thickness of a coating layer while forming different metal oxide layers on a coating portion coated on a substrate.
An iron oxide coating apparatus according to an embodiment of the present invention is an iron oxide coating apparatus for adjusting the thickness of at least one layer of a coating part formed of a plurality of layers on the surface of a substrate through a titration method, A plurality of tanks in which raw materials for each storage are stored, a reactor in which coating is performed by inputting substrates and raw materials, a supply control valve formed between the reactor and each tank to selectively control the supply of substrates and raw materials, and each supply It includes a control unit for controlling the control valve, and the layer coated by the titration method is made of iron nitride. In addition, an iron oxide coating method according to an embodiment of the present invention is a method of coating iron oxide in which a coating portion formed of a plurality of layers is formed on the surface of a substrate, comprising: a first step of preparing a substrate; A second step of preparing a precursor for forming a coating portion; A third step of forming a coating portion on the surface of the substrate, wherein at least one of the plurality of layers forming the coating portion forms a layer made of a metal oxide while adjusting the thickness using a titration method .

Description

Iron oxide coating apparatus and method {Apparatus and method for manufacturing iron oxide}

The present invention relates to an iron oxide coating apparatus and method, and more particularly, to an iron oxide coating apparatus and method capable of easily adjusting the type and thickness of a coating layer with respect to a substrate.

Pigments have been used as colorants in various fields, and generally do not dissolve in water and other organic solvents, and are physically and chemically stable. These pigments can be largely divided into inorganic pigments and organic pigments. Among them, various metals or metal oxides have been used as inorganic pigments, and various metals or metal oxides such as titanium dioxide, iron oxide, and silicon dioxide have been used alone or in combination to express various colors.

Iron oxide has various types of oxides such as FeO, Fe ₂ O ₃ , and Fe ₃ O ₄ in the chemical formula. Among them, Fe ₃ O ₄ is iron oxide used as a black pigment, and can be prepared by heating red iron oxide (Fe ₂ O ₃ ) at a high temperature in a reducing atmosphere to reduce some of Fe 3+ ions to Fe 2+ ions.

By the way, Korean Patent Publication No. 2001-0015911, Korean Patent Publication No. 2015-0048980 and the like are known as conventional methods for producing black iron oxide (Fe ₃ O ₄ ).

Korean Patent Publication No. 2001-0015911 discloses that hematite is contacted with a soluble source of Fe(II) ions in an aqueous alkaline medium in the presence of a soluble source of Fe(III) ions to convert hematite to Fe ₃ O ₄ . A method for preparing black iron oxide pigments from iron oxide having a hematite crystal structure is disclosed.

Korean Patent Publication No. 2015-0048980 discloses preparing a diluted iron sulfate solution containing iron sulfate (FeSO ₄ 7H ₂ O), mixing the flake matrix in ultrapure water (DIWater), and then stirring and dispersing to form a substrate suspension. and a flake substrate coating step of titrating a water-soluble inorganic salt solution to the substrate suspension, hydrolyzing the water-soluble inorganic salt solution, and mixing the prepared iron sulfate coating solution to coat the surface of the flake substrate with an oxide layer. Methods for preparing black luster pigments are disclosed.

However, these methods have a disadvantage in that several steps of chemical treatment are required using a suspension of iron oxide or a diluted iron sulfate solution containing iron sulfate, rather than iron oxide powder, which can be obtained inexpensively as a raw material.

On the other hand, iron oxide can be obtained by aqueous precipitation and hydrolysis of iron salts (Ullmann's Encyclopedia of Industrial Chemicals, VCH Weinheim 2006, Chapter 3.1.1. Iron Oxide Pigments, pp. 61-67). The iron oxide pigment obtained by the precipitation process is prepared from an iron salt solution and an alkaline compound in the presence of air.

As a method for producing iron oxide pigments, there is a Penniman method (US 1,327,061; US 1,368,748; US 2,937,927; EP 1106577A; US 6,503,315). Here, iron oxide pigments are prepared by dissolving and oxidizing metallic iron by adding iron salts and iron oxide nuclei. Thus, SHEN, Qing; SUN, Fengzhi; Wujiyan Gongye 1997, (6), 5-6 (CH), Wujiyan Gongye Bianjib, (CA 128:218378n) disclose how dilute nitric acid behaves on iron.

EP 1106577A discloses a variant of the Penniman process involving the action of dilute nitric acid on the iron to produce iron oxide with a nucleus, i.e. particle size of less than 100 nm. The reaction of iron with nitric acid is a complex reaction and, depending on the experimental conditions, can lead to passivation of the iron and thus cessation of the reaction or dissolution of the iron to form dissolved iron nitrate. Both reaction pathways are unfavorable and the preparation of microhematite is only successful under limited experimental conditions. EP 1106577A describes these conditions for producing microhematite. Here, iron is reacted with dilute nitric acid at a temperature in the range of 90 to 99°C. WO 2013/045608 describes a process for producing iron oxide pigments with an improved reaction process for producing fine hematite having a nucleus, ie, a particle size of 100 nm or less.

However, the Penniman process, which can directly produce iron oxides with a wide variety of color values and is efficient in itself, has the following disadvantages.

First, it is the release of nitrogen oxides. Nitrogen oxides can be toxic (for example the nitrous gases NO, NO ₂ and N ₂ O ₄ , commonly also referred to as “NO _X ”), produce smog, and when irradiated with UV light, degrade the atmosphere. It is a greenhouse gas that destroys the ozone layer. In particular, dinitrogen monoxide is a greenhouse gas that is about 300 times more potent than carbon dioxide. Also, dinitrogen monoxide is currently the strongest ozone-depleting substance. In the Penniman process with nitric acid, significant amounts of the nitrous gases NO and NO ₂ and also dinitrogen monoxide are formed.

In addition, the Penniman process using nitric acid produces nitrogen-containing wastewater containing significant amounts of nitrates, nitrites and ammonium compounds.

In addition, the Penniman method using nitric acid requires a lot of energy because a large volume of aqueous solution must be heated to a temperature of 60 to 120 ° C by introduction of external energy. Furthermore, by introducing an oxygen-containing gas as an oxidizing agent into the reaction mixture, energy is removed from the reaction mixture (steam stripping), which requires heat.

On the other hand, as a method of coating a metal oxide on a substrate such as mica, a fluidized bed chemical vapor deposition method and a uniform precipitation method are mainly used.

First, the fluidized bed chemical vapor deposition method is a method of coating a gaseous raw material on a substrate (mica) to be coated.

However, the fluidized bed chemical vapor deposition method has limitations in commercial use because it needs to heat to a high temperature as well as add raw materials added during coating (eg, adding SnO ₂ when TiO ₂ is coated).

On the other hand, the homogeneous precipitation method is a method in which OH- ions are released through a solution reaction such as hydrolysis without adding a precipitating agent to the solution from the outside when the precipitate is formed to make the precipitation.

However, since the homogeneous precipitation method exhibits strong acidity during the reaction process, it is necessary to neutralize the pH for safety. In addition, in the case of using the uniform precipitation method, since the metal oxide to be precipitated has an elliptical irregular shape, scattering of light occurs due to the shape, so there is a problem in that the quality of the pigment is deteriorated.

The description of the above background art is only for understanding the background of the present invention, and should not be taken as an admission that it corresponds to the prior art already known to those skilled in the art.

Korean Patent Registration No. 10-1858414 (Announcement date 2013.05.09)

The present invention provides an apparatus and method for coating iron oxide, which can be easily formed even at a low temperature when iron nitrate is coated on a substrate.

In addition, the present invention provides an iron oxide coating apparatus and method capable of easily adjusting the type and thickness of a coating layer by coating iron nitrate using a titration method without using a fluidized bed chemical vapor deposition method or a uniform precipitation method.

An iron oxide coating apparatus according to an embodiment of the present invention is an iron oxide coating apparatus for adjusting the thickness of at least one layer of a coating part formed of a plurality of layers on the surface of a substrate through a titration method, and coating the substrate. A plurality of tanks each containing raw materials for processing, a reactor in which coating is progressed by inputting the substrate and raw materials, and a supply control valve formed between the reactor and each tank to selectively control the supply of the substrate and raw materials. And, it includes a control unit for controlling each supply control valve, and the layer coated by the titration method is made of iron nitride.

The reactor is characterized in that it includes a stirrer for stirring the substrate and raw materials put into the reactor, and a motor for rotating the stirrer.

The tank includes a substrate tank for accommodating a substrate, a first tank for accommodating an iron nitrate precursor, a second tank for accommodating a tin oxide (SnO) precursor, a third tank for accommodating sodium hydroxide (NaOH), It is characterized in that it includes a fourth tank for accommodating sodium silicate (Na ₂ SiO ₃ ).

The supply control valve includes a substrate supply control valve for controlling the supply of the substrate, a first supply control valve for controlling the supply of the iron nitrate precursor, a second supply control valve for controlling the supply of the tin oxide (SnO) precursor, and , A third supply control valve for controlling the supply of sodium hydroxide (NaOH) and a fourth supply control valve for controlling the supply of sodium silicate (Na ₂ SiO ₃ ).

In order to check and process the coating process in real time, the reactor further comprises a thermometer for measuring the temperature inside the reactor, a pH meter for measuring the pH inside the reactor, and a heater for heating the inside of the reactor. with features

The control unit includes a motor controller for controlling the number of rotations of the motor during the process according to selective control of the first supply control valve to the fourth supply control valve, and a motor controller according to the selective control of the first supply control valve to the fourth supply control valve. A process time control unit for controlling a process time, a temperature control unit for adjusting the temperature inside the reactor in response to the selective control of the first supply control valve to the fourth supply control valve, the first supply control valve, and the second supply control valve A pH control unit controlling the pH inside the reactor in real time by controlling the third supply control valve in response to the selective control of the valve and the fourth supply control valve, and the first supply in response to the control of the temperature control unit and the pH control unit It is characterized in that it includes a raw material supply rate control unit for controlling the feed rate of the raw material by controlling the control valve to the fourth supply control valve.

On the other hand, an iron oxide coaching method according to an embodiment of the present invention is a method of coating iron oxide using the iron oxide coating apparatus described above, comprising: a first step of preparing a substrate; A second step of preparing a precursor for forming a coating portion; A third step of forming a coating portion on the surface of the substrate, wherein at least one of the plurality of layers forming the coating portion forms a layer made of a metal oxide while adjusting the thickness using a titration method .

In the first step, the substrate is prepared as a flake having a thickness of 0.1 to 10 μm using natural mica or synthetic mica, and in the second step, the precursor is tin oxide (tin oxide forming the first metal oxide layer) SnO) precursor and an iron nitrate precursor forming the second metal oxide layer.

In the third step, a first step of injecting ultrapure water (D.I.Water) and a base material into a reactor through which current flows between the stirring bar and the inner wall; A second process of adding HCl and the tin oxide (SnO) precursor to the reactor and stirring them to form a first metal oxide layer formed of tin oxide (SnO) having a rutile crystal structure on the surface of the substrate; a third step of injecting HCl and the iron nitrate precursor into the reactor and stirring them to form a second metal oxide layer formed of iron nitrate on the surface of the first metal oxide layer; a fourth process of dehydrating in the reactor and then washing the substrate on which the first metal oxide layer and the second metal oxide layer are formed using ultrapure water; and a fifth process of recovering pigment particles by drying the substrate on which the first metal oxide layer and the second metal oxide layer are formed.

The third step may further include a sixth step of further forming a protective layer by coating sodium silicate (Na ₂ SiO ₃ ) on the surface of the pigment particle after the fifth step.

a seventh process of injecting ultrapure water (D.I. Water) and the pigment particles having the protective layer into the reactor through which current flows between the stirring bar and the inner wall after the sixth process; It is characterized in that it further comprises an eighth process of forming a third metal oxide layer formed of iron nitrate on the surface of the protective layer by introducing HCl and the iron nitrate precursor into the reactor and stirring them.

The third process and the eighth process are characterized in that the formation thickness of the second metal oxide layer and the third metal oxide layer is adjusted by adjusting the stirring time after adding the iron nitrate precursor.

The third process and the eighth process are characterized by stirring for 3 to 12 hours at pH 3.5 and a temperature of 70 to 80 ° C.

The third process and the eighth process are characterized in that the coating speed is maintained at 20 ~ 30 nm / hr.

According to an embodiment of the present invention, when iron nitrate is coated on a substrate, an effect that can be easily formed even at a low temperature can be expected.

In addition, by coating using a titration method, an effect of easily adjusting the thickness of the coating layer can be expected.

In addition, it is superior in terms of production time and production volume to the conventional fluidized bed chemical vapor deposition method or uniform precipitation method, and it is possible to produce high quality iron oxide pigment with low manufacturing cost.

In addition, according to an embodiment of the present invention, the coating part can be formed with three or more composite layers to form an excellent refractive index, and accordingly, color anisotropy, dichroism, and birefringence in which direct color and indirect color change depending on the angle are improved. can indicate

In addition, by coating two or more metal oxides, the light absorption rate is reduced and the reflectance is increased, so that the gloss can be expressed more effectively.

In addition, since all processes are performed inside the reactor, rapid processing is possible.

1 is a cross-sectional view showing iron oxide pigment particles according to an embodiment of the present invention,
2 is a cross-sectional view showing iron oxide pigment particles according to another embodiment of the present invention,
3 is a block diagram of an iron oxide coating apparatus according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, only these embodiments will complete the disclosure of the present invention, and will fully cover the scope of the invention to those skilled in the art. It is provided to inform you. Like reference numerals designate like elements in the drawings.

First, the refractive index is first described for easy explanation of the present invention.

The index of refraction refers to the rate at which the speed of light decreases as it travels through different media. Optically, light has a wave-particle duality, being both a particle and a wave. Waves of light have different velocities in different media. That is, the speed is different when light travels in air or vacuum and when light collides with iron nitrate and is divided into reflected light and refracted light. The degree to which light bends when passing through a boundary between different media is called the index of refraction.

On the other hand, it is known that the refractive index is higher than that of other metal oxides when the reference medium is air and the opposite medium is iron nitrate. This relative refractive index can be explained by Snell's law.

1 is a cross-sectional view showing iron oxide pigment particles according to an embodiment of the present invention.

As shown in FIG. 1, an iron oxide pigment particle according to an embodiment of the present invention includes a substrate 100; Doedoe coated on the surface of the base material 100, and includes a coating portion 200 formed by coating at least two different metal oxides step by step.

As the substrate 100, thin mica (Mica) is used. At this time, natural mica or synthetic mica may be used as the mica.

For example, as the substrate 100, flaky mica having a refractive index of about 1.5 and a thickness of 0.1 to 10 μm may be used. At this time, it is preferable to use a white color and an even surface.

The coating unit 200 may be implemented as a plurality of layers by coating different metal oxides in stages to have various refractive indices.

For example, the coating unit 200 may include a first metal oxide layer 210 coated on a surface of a substrate; a second metal oxide layer 220 coated on the surface of the first metal oxide layer 210; A protective layer 230 coated on the surface of the second metal oxide layer 220 is included.

At this time, the first metal oxide layer 210 is formed of tin oxide (SnO) having a rutile crystal structure, the second metal oxide layer 220 is formed of iron nitrate, and the protective layer 230 is sodium silicate (Na ₂ SiO ₃ ). At this time, iron nitrate preferably has a rutile crystal structure.

Therefore, since the first metal oxide layer 210 and the second metal oxide layer 220 form different high refractive indexes, the color expression is clear, and the direct color and the indirect color are clear, so that the iron oxide pigment having high luminance can be implemented. .

Meanwhile, the first metal oxide layer 210 is formed of tin oxide (SnO) having a rutile crystal structure. When forming the second metal oxide layer 220 formed in the process is possible even at a low temperature.

Tin oxide (SnO) forming the first metal oxide layer 210 has a characteristic of reducing light absorption, and since light absorption and reflection have a complementary color effect, the first metal oxide layer 210 is tin oxide. By forming with (SnO), an iron oxide pigment with excellent refractive index can be implemented.

The second metal oxide layer 220 is formed of iron nitrate, and since the first metal oxide layer 210 is formed of tin oxide (SnO) having a rutile crystal structure, iron nitrate can be easily implemented at a low temperature. At this time, the second metal oxide layer 220 may be formed while controlling its thickness using a titration method. At this time, it is preferable that the second metal oxide layer 220 has a thickness of 10 to 150 nm.

Iron nitrate forming the second metal oxide layer 220 has a very high refractive index, anisotropy and non-toxicity, and has a high hiding power, so it is insoluble in all solvents. In addition, strong bases such as NaOH and iron nitrate are synthesized by titration, and the synthesized product has an excellent color reaction (or color reaction), so it is advantageous to synthesize iron oxide pigments from matte to glossy, and has high color development and coloring power. It is possible to implement an iron oxide pigment with a higher quality than conventional iron oxide pigments.

The protective layer 230 is preferably formed of sodium silicate (Na ₂ SiO ₃ ), which is an inorganic adhesive.

Sodium silicate (Na ₂ SiO ₃ ) forming the protective layer 230 is an inorganic adhesive having solvent resistance, and can further enhance the solvent resistance of the second metal oxide layer 220 .

Meanwhile, in the present invention, a metal oxide layer may be further formed on the coating portion in order to implement a more diverse refractive index.

2 is a cross-sectional view showing iron oxide pigment particles according to another embodiment of the present invention.

As shown in FIG. 2 , iron oxide pigment particles according to another embodiment of the present invention include a substrate 100 as in the above-described embodiment; Doedoe coated on the surface of the base material 100, and includes a coating portion 200 formed by coating at least two different metal oxides step by step. In addition, the coating unit 200 includes a first metal oxide layer 210 coated on the surface of the substrate 100; a second metal oxide layer 220 coated on the surface of the first metal oxide layer 210; A protective layer 230 coated on the surface of the second metal oxide layer 220 is included. However, in this embodiment, a third metal oxide layer 240 formed of iron nitrate and having a thickness different from that of the second metal oxide layer 220 is further formed on the surface of the protective layer 230 .

At this time, the third metal oxide layer 240 is preferably formed of iron nitrate having the same crystal structure as the second metal oxide layer 220 .

At this time, the third metal oxide layer 240 can also be formed while controlling its thickness using a titration method similarly to the second metal oxide layer 220 . Therefore, the thickness of the third metal oxide layer 240 is also preferably formed to be 10 to 150 nm.

However, it is preferable that the thickness of the third metal oxide layer is different from that of the second metal oxide layer 220 .

Therefore, it is possible to realize various colors of iron oxide pigments by differentiating a direct color from an indirect color by the second metal oxide layer 220 and the third metal oxide layer 240 exposed to the outermost part.

3 is a block diagram of an iron oxide coating apparatus according to an embodiment of the present invention.

As shown in FIG. 3, the iron oxide coating apparatus according to an embodiment of the present invention includes a plurality of tanks 300 in which raw materials for coating a substrate are respectively accommodated, and a reactor in which coating is performed by inputting the substrate and raw materials 400, a supply control valve 500 formed between the reactor 400 and each tank 300 to selectively control the supply of substrates and raw materials, and a control unit for controlling each supply control valve 500 ( 600).

The reactor 400 includes a stirrer 410 for stirring the substrate and raw materials put into the reactor 400 and a motor 420 for rotating the stirrer 410 . Here, the stirrer 410 may be a stir bar.

The tank 300 includes a substrate tank 310 for accommodating a substrate, a first tank 320 for accommodating an iron nitrate precursor, a second tank 330 for accommodating a tin oxide (SnO) precursor, and sodium hydroxide It includes a third tank 340 accommodating (NaOH) and a fourth tank 350 accommodating sodium silicate (Na ₂ SiO ₃ ).

Here, 15 to 25 L of HCl, 15 to 25 kg of D.I.Water, and 0.5 to 2.5 kg of tin oxide are added to the second tank 330 to form a tin oxide (SnO) precursor. Meanwhile, the second tank 330 may be formed of three subdivided tanks, and each subdivided tank may be directly supplied to the reactor 400 through each valve. That is, HCl, D.I.Water, and tin oxide (Tin Oxide) may be directly supplied to the reactor 400 to form a tin oxide (SnO) precursor in the reactor 400, or HCl and D.I.Water required for other processes may be During the process, it may be directly supplied to the reactor 400.

The supply control valve 500 controls the supply of the substrate supply control valve 510 for controlling the supply of the substrate, the first supply control valve 520 for controlling the supply of the iron nitrate precursor, and the supply of the tin oxide (SnO) precursor. A second supply control valve 530 for controlling, a third supply control valve 540 for controlling the supply of sodium hydroxide (NaOH), and a fourth supply control valve for controlling the supply of sodium silicate (Na ₂ SiO ₃ ) Includes (550). In this way, the supply control valve 500 may be formed in each supply pipe connected to each tank.

On the other hand, in order to check and process the coating process in real time, the reactor 400 includes a thermometer 430 for measuring the temperature inside the reactor 400, a pH meter 440 for measuring the pH inside the reactor 400, and , A heater 450 for heating the inside of the reactor 400 is further configured.

The control unit 600 includes a motor controller 610 for adjusting the number of rotations of the motor 420 during the process according to the selective control of the first supply control valve 520 to the fourth supply control valve 550, and The process time controller 620 for controlling the process time according to the selective control of the supply control valve 520 to the fourth supply control valve 550, and the first supply control valve 520 to the fourth supply control valve 550 ) Corresponding to the selective control of the temperature controller 630 for controlling the temperature inside the reactor 400, the first supply control valve 520, the second supply control valve 530 and the fourth supply control valve 550 In response to the selective control of ), the third supply control valve 540 is controlled to adjust the pH inside the reactor 400 in real time, the pH control unit 640, the temperature control unit 630, and the pH control unit 640 In response to the control of ), the first supply control valve 520 to the fourth supply control valve 550 are controlled to control the input speed of the raw material.

Here, the motor controller 610 is connected to the motor 420 to control the speed of the motor 420 for each process, and the process time control unit 620 includes the motor controller 610, the temperature control unit 630, the pH It is connected to the control unit 640 and the raw material supply speed control unit 650 respectively to control the process time in real time, and the temperature control unit 630 is connected to the thermometer 430 and the heater 450 to correspond to the temperature sensed value. to control the temperature of the heater for each process, the pH control unit 640 is connected to the pH meter 440 to control the pH for each process, and the raw material supply rate control unit 650 is connected to the supply control valve 500 Controls the real-time supply amount of each supply control valve (510, 520, 530, 540, 550).

On the other hand, after each process is completed, an outlet (not shown) is formed in the reactor 400 to discharge the raw material input into the reactor 400, and the outlet is formed with a discharge pipe (not shown) formed with a discharge valve (not shown) and It is connected.

In the iron oxide coating apparatus configured as described above, the substrate supply control valve 510 is controlled to input the substrate into the reactor 400, and the first supply control valve 520 to the fourth supply control valve 550 are selectively controlled to A coating unit 200 is formed on the substrate.

Here, as an example, a process of forming the coating unit 200 on a substrate using an iron oxide coating device will be described.

First, the control unit 600 controls the substrate supply control valve 510 to input the substrate into the reactor 400, and then controls the second supply control valve 530 to supply the tin oxide (SnO) precursor to the reactor 400. Put in and stir. Accordingly, a first metal oxide layer formed of tin oxide (SnO) having a rutile crystal structure is formed on the surface of the substrate. At this time, 15 ~ 25ℓ of HCl, 15 ~ 25kg of D.I.Water, and 0.5 ~ 2.5kg of tin oxide (Tin Oxide), a precursor of tin oxide (SnO), were added to the second tank 330, and tin oxide was stirred in advance. It is preferable to feed the (SnO) precursor to the reactor 400. Of course, when the second tank 330 is divided into three, it may be directly supplied to the reactor 400 from each tank.

Subsequently, the control unit 600 controls the first supply control valve 520 to inject and stir the iron nitrate precursor to form a second metal oxide layer formed of iron nitrate on the surface of the first metal oxide layer.

Here, when the first metal oxide layer and the second metal oxide layer are formed, the control unit 600 controls the third supply control valve 540 to inject sodium hydroxide (NaOH) into the reactor 400 so that the reactor 400 ) The internal pH can be adjusted in real time within the range of 1.6 ~ 7.5. In the present invention, the pH is adjusted within the range of 3.5 ± 0.5 to coat iron nitrate. In addition, the temperature inside the reactor 400 can be adjusted in real time. In this way, various iron oxides as well as desired iron oxide can be obtained by controlling the pH and temperature inside the reactor 400 in real time by interlocking with the feed rate of the raw material. In addition, since each supply control valve is controlled by the controller 600, it is easy to apply a titration method and easily adjust the thickness of the second metal oxide layer.

Meanwhile, when the process of forming the second metal oxide layer is completed, the control unit 600 controls the fourth supply control valve 550 to inject sodium silicate (Na ₂ SiO ₃ ) into the reactor 400 so that the second metal oxide layer is formed. A protective layer may be formed on the surface of the oxide layer.

In addition, when the process of forming the protective layer is completed, the control unit 600 controls the first supply control valve 520 to input and stir the iron nitrate precursor to form a third metal oxide layer of iron nitrate on the surface of the protective layer. can form

Meanwhile, after each process is completed, a dehydration and washing process may be performed, and ultrapure water may be used for the dehydration and washing process, and may be performed inside the reactor 400 in real time. That is, when each process is completed, the agitator 410 and the heater 450 formed in the reactor 400 are operated to perform dehydration and washing processes inside the reactor 400 . As such, in the present invention, since all processes are processed in the reactor 400, rapid process processing is possible. That is, in the conventional method, manual work of taking out the substrate for the dehydration and washing process performed after each process was required, but by preventing such manual work, process automation and rapid processing are possible.

A method of coating iron oxide using the iron oxide coating device configured as described above will be described.

An iron oxide coating method according to an embodiment of the present invention includes a first step of preparing a substrate; A second step of preparing a precursor for forming a coating portion; A third step of forming a coating portion on the surface of the substrate, wherein at least one of the plurality of layers forming the coating portion forms a layer made of a metal oxide while adjusting the thickness using a titration method .

At this time, in the first step, the substrate is prepared as a thin piece having a thickness of 0.1 to 10 μm using natural mica or synthetic mica.

And, in the second step, the precursor is separately prepared from a tin oxide (SnO) precursor forming the first metal oxide layer and an iron nitrate precursor forming the second metal oxide layer.

Here, the tin oxide (SnO) precursor uses a tin oxide (Tin Oxide)-based material and uses an iron nitrate precursor.

When the substrate, the tin oxide (SnO) precursor, and the iron nitrate precursor are prepared in this way, a plurality of coating parts are sequentially coated on the substrate.

So, the third step is the first step of introducing ultrapure water (D.I.Water) and the substrate into the reactor 400 through which current flows between the agitating bar and the inner wall; A second process of adding HCl and the tin oxide (SnO) precursor to the 400 and stirring to form a first metal oxide layer formed of tin oxide (SnO) having a rutile crystal structure on the surface of the substrate class; a third process of adding HCl and the iron nitrate precursor to the reactor 400 and stirring them to form a second metal oxide layer formed of iron nitrate on the surface of the first metal oxide layer; a fourth process of dehydrating in the reactor 400 and then washing the substrate on which the first metal oxide layer and the second metal oxide layer are formed using ultrapure water; and a fifth process of recovering pigment particles by drying the substrate on which the first metal oxide layer and the second metal oxide layer are formed.

Meanwhile, in the third process of forming the second metal oxide layer, the thickness of the second metal oxide layer may be adjusted using a titration method.

The titration method is one of the important operations in quantitative analysis. It is a method of finding out and coating it by dropping it drop by drop. This can be achieved through real-time control of the supply control valve 500 by the control unit 600 . Therefore, it is easy to productively control the thickness of the coating layer by precipitating iron nitrate produced by neutralizing nitrate with ammonia or sodium hydroxide (2NaOH) and coating it on mica.

And, after the fifth process, a sixth process of further forming a protective layer on the surface of the second metal oxide layer by coating sodium silicate (Na ₂ SiO ₃ ) on the surface of the pigment particle is further performed.

On the other hand, as in the other embodiments described above, after the sixth process to further form a third metal oxide layer on the surface of the protective layer, in the reactor 400 where current flows between the stirring bar and the inner wall, ultrapure water (D.I.Water) and the above a seventh step of injecting pigment particles having a protective layer formed thereon; An eighth process of forming a third metal oxide layer formed of iron nitrate on the surface of the protective layer by adding HCl and the iron nitrate precursor to the reactor 400 and stirring may be further performed.

The iron oxide coating method as described above will be described through specific examples.

In the present invention, it is preferable to control the time for adding and stirring the iron nitrate precursor in the above-described third process in order to adjust the formation thickness of the second metal oxide layer using a titration method.

15 ~ 30ℓ of D.I.Water and 1.5 ~ 3.5kg of 0.1 ~ 10㎛ mica (Calcium Aluminum Borosilicate) are added to the 50ℓ reactor (400) and stirred while maintaining the temperature at 70 ~ 80 ℃. At this time, the stirring bar uses stainless steel made of SU316L, in which Mo is synthesized, and the stirring is started by the motor stirrer.

In addition to the substrate tank 310, four tanks capable of introducing raw materials into the reactor 400 are prepared.

So, the iron nitrate precursor is prepared in the first tank 320, and in the second tank 330, 15 to 25 liters of HCl, 15 to 25 kg of D.I.Water, and tin oxide (SnO) precursor, tin oxide Prepare by stirring 0.5 ~ 2.5 kg.

Then, NaOH is prepared for pH adjustment in the third tank 340, and sodium silicate (Na ₂ SiO ₃ ) aqueous solution for forming a protective layer is prepared in the fourth tank 350.

When the raw materials are prepared in this way, the raw materials prepared in the first tank 320 to the fourth tank 350 are introduced into the reactor 400 according to a predetermined order to perform coating.

At this time, the supply rate of the raw materials introduced into the reactor 400 from the first tank 320 to the fourth tank 350 is maintained at a rate of 5±3 ml/min.

And, after adjusting the pH of the inside of the reactor 400 to 3.5, the coating is started. Of course, the pH can be adjusted to obtain the desired iron oxide.

First, raw materials are supplied from the second tank 330 and the third tank 340 to the reactor 400, and maintained for 30 minutes while stirring at 35±5 RPM. Then, inside the reactor 400, tin oxide (Tin Oxide), a precursor of tin oxide (SnO), reacts to form a first metal oxide layer on the surface of the substrate.

Then, raw materials are supplied from the first tank 320 and the third tank 340 to the reactor 400, and maintained for a set time (eg, 3 to 4 hours) while stirring at 45 ± 5 RPM. Then, inside the reactor 400, a second metal oxide layer is formed while being coated on the surface of the first metal oxide layer at a rate of 20 to 30 nm/hr.

Subsequently, the substrate on which the first metal oxide layer and the second metal oxide layer are formed is dehydrated in the reactor 400 and washed four times using D.I.Water. At this time, the agitator 410 and the heater 450 formed in the reactor 400 are operated to perform dehydration and washing processes inside the reactor 400 .

Then, the substrate on which the first metal oxide layer and the second metal oxide layer are formed is put into the reactor 400 again, and maintained for 1 hour while stirring at 45±5 RPM. Then, a protective layer is formed on the surface of the second metal oxide layer.

Subsequently, the substrate on which the protective layer is formed is dehydrated in the reactor 400 and washed 4 times using D.I.Water. At this time, the agitator 410 and the heater 450 formed in the reactor 400 are operated to perform dehydration and washing processes inside the reactor 400 .

After washing, dry at 350 ℃ for 24 hours.

Thus, an iron oxide pigment in which iron nitrate having a thickness of 40 to 60 nm forms the second metal layer was recovered. The recovered iron oxide pigment had a very high refractive index.

Meanwhile, by controlling the time for forming the second metal oxide layer, iron oxide pigments having various thicknesses and colors may be prepared. That is, as the process time increases, a thicker second metal oxide layer may be formed.

As can be seen from the above embodiments, the thickness of the second metal oxide layer can be adjusted to a desired level by adjusting the coating time of the second metal oxide layer using a titration method, and the thickness of the second metal oxide layer can be adjusted to a desired level. You can adjust the color implemented according to the thickness.

In addition, as can be seen from the comparison between the Examples and Comparative Examples, when the first metal oxide layer is formed first before forming the second metal oxide layer and SnO is used together in the formation of the second metal oxide layer, 70 to 70 It was confirmed that iron nitrate can be formed even at a relatively low temperature of 80°C.

Meanwhile, while the first metal oxide layer and the second metal oxide layer are formed, the pH inside the reactor 400 is adjusted while NaOH is supplied to the third tank 340 for pH control. The hydrolysis reaction condition for forming the first metal oxide layer or the second metal oxide layer is preferably maintained at a pH of 1.6 to 7.5 at a temperature of 70 to 80 °C.

If the temperature inside the reactor 400 is lower than 70° C., the reaction proceeds slowly, so that the first metal oxide layer and the second metal oxide layer having a desired thickness are not formed. Also, if the temperature inside the reactor 400 is higher than 80° C., a problem in which hydrolysis occurs in a tank containing raw materials rather than in the reactor 400 may occur.

In addition, the pH inside the reactor 400 is preferably maintained at 1.6 to 7.5 during the reaction, starting at 3.5. If the pH inside the reactor 400 is higher than 7.5, a problem may occur in which desired gloss is not realized.

In addition, it is preferable to implement various colors of white, yellow, red, blue and green by forming the coating thickness of the first metal oxide layer or the second metal oxide layer coated on the substrate to be 10 to 150 nm.

Also, the coating speed of the first metal oxide layer or the second metal oxide layer coated on the substrate is preferably maintained at 20 to 30 nm/hr. If the coating speed is slower than the suggested speed, a problem of slow reaction speed may occur, and if the coating speed is faster than the suggested speed, a problem of not properly coating may occur.

Although the present invention has been described with reference to the accompanying drawings and preferred embodiments described above, the present invention is not limited thereto, but is limited by the claims described below. Therefore, those skilled in the art can variously modify and modify the present invention within the scope not departing from the technical spirit of the claims described below.

The technical idea of the present invention was examined through several examples.

It is obvious that a person skilled in the art to which the present invention pertains can variously modify or change the above-described embodiments from the description of the present invention. In addition, even if not explicitly shown or described, a person skilled in the art may make various modifications from the description of the present invention to the technical idea according to the present invention. is obvious, which still belongs to the scope of the present invention. The above embodiments described with reference to the accompanying drawings are described for the purpose of explaining the present invention, and the scope of the present invention is not limited to these embodiments.

100: base material 200: coating part
210: first metal oxide layer 220: second metal oxide layer
230: protective layer 240: third metal oxide layer
300: tank 400: reactor
500: supply control valve 600: control unit

Claims (12)

At least one of the coating parts formed of a plurality of layers on the surface of the substrate is an iron oxide coating device for adjusting the thickness through a titration method,
a plurality of tanks in which raw materials for coating the substrate are respectively accommodated;
A reactor in which coating is performed by inputting the substrate and raw materials;
Supply control valves formed between the reactor and each tank to selectively control the supply of the substrate and the raw material;
Includes a control unit for controlling each supply control valve,
The layer coated by the titration method is made of iron nitrate,

The tank includes a substrate tank for accommodating a substrate, a first tank for accommodating an iron nitrate precursor, a second tank for accommodating a tin oxide (SnO) precursor, a third tank for accommodating sodium hydroxide (NaOH), A fourth tank for accommodating sodium silicate (Na ₂ SiO ₃ ),

The reactor includes a stirrer for stirring the substrate and raw materials put into the reactor, and a motor for rotating the stirrer,

The supply control valve includes a substrate supply control valve for controlling the supply of the substrate, a first supply control valve for controlling the supply of the iron nitrate precursor, a second supply control valve for controlling the supply of the tin oxide (SnO) precursor, and , a third supply control valve for controlling the supply of sodium hydroxide (NaOH) and a fourth supply control valve for controlling the supply of sodium silicate (Na ₂ SiO ₃ ),

The control unit,
A motor controller for controlling the number of rotations of a motor during a process by selectively adjusting the first supply control valve to the fourth supply control valve, and controlling the process time by selectively adjusting the first supply control valve to the fourth supply control valve A process time controller that controls the temperature inside the reactor in response to the selective control of the first supply control valve to the fourth supply control valve, the first supply control valve, the second supply control valve, and the fourth supply control valve. A pH control unit controlling the pH inside the reactor in real time by controlling the third supply control valve in response to the selective control of the supply control valve, and the first supply control valves to the first supply control valves in response to the control of the temperature control unit and the pH control unit 4 includes a raw material supply speed control unit that controls the supply control valve to control the input speed of the raw material,

In order to check and process the coating process in real time, a thermometer for measuring the temperature inside the reactor, a pH meter for measuring the pH inside the reactor, and a heater for heating the inside of the reactor are installed in the reactor,

The motor controller is connected to the motor and controls the speed of the motor for each process,
The process time control unit is connected to the motor controller, temperature control unit, pH control unit and raw material supply speed control unit to control the process time in real time,
The temperature control unit is connected to the thermometer and the heater to control the temperature of the heater for each process in response to the temperature sensing value,
The pH control unit is connected to the pH meter to control the pH for each process,
The raw material supply speed control unit is connected to the supply control valve to control the real-time supply amount of each supply control valve,

The reactor is formed with a discharge port for discharging the input raw material,
The outlet is connected to a discharge pipe formed with a discharge valve,

When each process is completed, the discharge valve is opened to discharge the raw material input for the process, and then the dehydration and washing process is performed for the product after each process is completed. Iron oxide coating apparatus proceeding with. delete delete delete delete delete A method of coating iron oxide using the iron oxide coating apparatus of claim 1,
A first step of preparing a substrate;
A second step of preparing a precursor for forming a coating portion;
A third step of forming a coating portion on the surface of the substrate, wherein at least one layer of a plurality of layers forming the coating portion forms a layer made of a metal oxide while adjusting the thickness using a titration method, ,
In the first step, the substrate is prepared as a thin piece having a thickness of 0.1 to 10 μm using natural mica or synthetic mica,
In the second step, the precursor includes a tin oxide (SnO) precursor forming a first metal oxide layer and an iron nitrate precursor forming a second metal oxide layer,
The third step,
A first step of injecting ultrapure water (DIWater) and a substrate into a reactor in which current flows between the agitation bar and the inner wall;
A second process of adding HCl and the tin oxide (SnO) precursor to the reactor and stirring them to form a first metal oxide layer formed of tin oxide (SnO) having a rutile crystal structure on the surface of the substrate;
a third step of injecting HCl and the iron nitrate precursor into the reactor and stirring them to form a second metal oxide layer formed of iron nitrate on the surface of the first metal oxide layer;
a fourth process of dehydrating in the reactor and then washing the substrate on which the first metal oxide layer and the second metal oxide layer are formed using ultrapure water;
and a fifth step of recovering pigment particles by drying the substrate on which the first metal oxide layer and the second metal oxide layer are formed. The method of claim 7,
The third step,
The iron oxide coating method further comprising a sixth step of further forming a protective layer by coating sodium silicate (Na ₂ SiO ₃ ) on the surface of the pigment particle after the fifth step. The method of claim 8,
After the 6th process above
a seventh step of injecting ultrapure water (DIWater) and the pigment particles on which the protective layer is formed into a reactor through which current flows between the stirring bar and the inner wall;
An eighth process of adding HCl and the iron nitrate precursor to the reactor and stirring them to form a third metal oxide layer formed of iron nitrate on the surface of the protective layer. The method of claim 9,
The third process and the eighth process are characterized in that the iron oxide coating method, characterized in that the formation thickness of the second metal oxide layer and the third metal oxide layer is adjusted by adjusting the stirring time of the iron nitrate precursor. The method of claim 10,
The third process and the eighth process are iron oxide coating method, characterized in that stirring for 3 to 12 hours at pH 3.5 and temperature 70 ~ 80 ℃ conditions. The method of claim 11,
The iron oxide coating method, characterized in that the third process and the eighth process maintains the coating speed at 20 ~ 30nm / hr.

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