KR20190089414A - Inorganic PARTICLE AND METHOD FOR MANUFACTURING THE SAME - Google Patents

Abstract

The present invention relates to an inorganic particle containing titanium dioxide, calcium carbonate and magnesium carbonate and a method for manufacturing the inorganic particle. The inorganic particle of the present invention contains titanium dioxide, calcium carbonate and magnesium carbonate at an optimal ratio, thereby being capable of forming a paint film having excellent outer appearance and concealing functions when forming a paint film with a paint comprising the inorganic particle.

Description

FIELD OF THE INVENTION The present invention relates to inorganic particles,

The present invention relates to inorganic particles containing titanium dioxide and a process for producing the inorganic particles.

Titanium dioxide (TiO ₂ ) is used for various purposes in fields such as paints, paper, cosmetics, and batteries. This is because titanium dioxide is excellent in its ability to scatter visible light, is biologically and chemically harmless, and stable in an acidic or basic organic solvent.

However, since titanium dioxide is an expensive material, many studies have been made to replace it. For example, there is a technique in which the surface of titanium dioxide is coated with calcium carbonate to prepare a titanium dioxide composite, thereby reducing the amount of titanium dioxide used (see Patent Literature).

 However, the titanium dioxide composite disclosed in the related art has a problem in that the whiteness is not sufficient and the hiding power is inferior. In addition, a special manufacturing facility must be used to produce the titanium dioxide composite, and manufacturing efficiency is low due to the complicated manufacturing process.

Korean Patent Publication No. 1999-0087473

The present invention provides an inorganic particle capable of enhancing hiding power in addition to the appearance of a coating film.

The present invention also provides a process for producing the inorganic particles.

The present invention provides an inorganic particle comprising titanium dioxide, calcium carbonate, and magnesium carbonate, wherein the mixing ratio of the titanium dioxide, the calcium carbonate, and the magnesium carbonate is 1: 1 to 5: 0.5 to 3.

The magnesium carbonate is a carbonate containing magnesium, for example, magnesium bicarbonate, hydromagnesite and the like.

The present invention also relates to a process for preparing a mixture containing calcium hydroxide and magnesium hydroxide by reacting a calcium and magnesium containing raw material with a solvent, adding a titanium dioxide to the mixture to prepare a suspension, introducing a carbon dioxide-containing gas into the suspension And then stabilizing the pH of the reaction product obtained by the reaction.

The calcium and magnesium containing material is gyeongso dolomite (CaO · MgO), magnesium (MgO) and calcium oxide (CaO), magnesium hydroxide (Mg (OH) _2), calcium hydroxide (Ca (OH) ₂₎ from the group consisting of selected It may be more than one kind.

And removing the foreign substances contained in the mixture before the titanium dioxide is added.

The content of carbon dioxide contained in the gas may be 10 to 50% by concentration.

Since the inorganic particles of the present invention contain titanium dioxide, calcium carbonate, and magnesium carbonate in an optimum ratio, a coating containing the same can be formed with excellent appearance and hiding power at the time of forming a coating.

In addition, the present invention can increase the production efficiency of inorganic particles and ensure economical efficiency by manufacturing inorganic particles by simple manufacturing facilities and manufacturing processes.

1 is an image obtained by analyzing an inorganic particle according to Example 1 of the present invention by a scanning electron microscope.
2 is an image obtained by analyzing an inorganic particle according to Example 1 of the present invention by a transmission electron microscope.
Fig. 3 shows the results of X-ray diffraction analysis of the inorganic particles according to Example 1 of the present invention.

Hereinafter, the present invention will be described.

1. Inorganic particles

The inorganic particles of the present invention include titanium dioxide, calcium carbonate, and magnesium carbonate.

The titanium dioxide (TiO ₂ ) contained in the inorganic particles of the present invention has a high light scattering (refraction) property and serves to impart a white color to the inorganic particles.

The titanium dioxide may have a rutile crystal phase in an inorganic particle, but is not limited thereto.

The average particle size (D50) of the titanium dioxide may be 150 to 350 nm, for example, 200 to 300 nm, considering the production efficiency of the inorganic particles and the hiding power of the coating film.

The calcium carbonate (CaCO ₃ ) contained in the inorganic particles of the present invention binds with titanium dioxide and serves as a spacing agent to keep the interval between titanium dioxide particles constant. By such calcium carbonate, the titanium dioxide particles are spaced apart at regular intervals, thereby increasing the light scattering property of the titanium dioxide.

The calcium carbonate may be one having a calcite and an aragonite crystal phase in an inorganic particle.

The magnesium carbonate contained in the inorganic particles of the present invention has fine grooves formed on the surface thereof and serves to form an air layer on the coating film when the coating film is formed with a paint containing inorganic particles. As the air layer is formed on the coating film by the magnesium carbonate, the scattering effect of the inorganic particles is increased, and the hiding power of the coating film can be increased.

The magnesium carbonate is a carbonate containing magnesium, for example, magnesium bicarbonate, hydromagnesite and the like.

The inorganic particles of the present invention may have a weight ratio of the titanium dioxide, the calcium carbonate, and the magnesium carbonate in a weight ratio of 1: 1 to 5: 0.5 to 3, for example, 1: 1.5 to 3: 2 to 3 Weight ratio. If the mixing ratio of titanium dioxide, calcium carbonate and magnesium carbonate contained in the inorganic particles is out of the above range, the production efficiency of the inorganic particles may be lowered, and the appearance (glossiness) and hiding power of the coating film may be lowered.

2. Manufacturing method of inorganic particles

The present invention provides a method for producing the above-described inorganic particles, which will be described in detail as follows.

First, a mixture containing calcium hydroxide and magnesium hydroxide is prepared by reacting a calcium and magnesium containing raw material with a solvent.

The calcium and magnesium-containing material may be a known, e.g. gyeongso dolomite (CaO · MgO), magnesium (MgO) and calcium oxide (CaO), magnesium hydroxide (Mg (OH) _2), calcium hydroxide ( Ca (OH) ₂ ). The dolomite is composed of 40 to 60 wt% of CaO and 60 to 40 wt% of MgO, the particle size may be 0.01 to 10 mm, and 200 to 300 parts by weight may be included based on 100 parts by weight of titanium dioxide described later. The particle sizes of the magnesium oxide and calcium oxide may be 0.01 to 10 mm, respectively, and may be 100 to 150 parts by weight based on 100 parts by weight of titanium dioxide described later. The magnesium hydroxide may have a particle size of 0.01 to 10 mm and may be contained in an amount of 100 to 250 parts by weight based on 100 parts by weight of titanium dioxide described later. The particle size of the calcium hydroxide may be 0.01 to 10 mm, and may be 100 to 200 parts by weight based on 100 parts by weight of titanium dioxide described later. If the particle size of the raw materials is out of the above range, the production time of the inorganic particles may be prolonged, and if the content is out of the above range, the hiding power may be lowered.

The solvent may be any conventionally known aqueous solvent, for example, water, distilled water or deionized water.

The reaction of the calcium and magnesium containing raw material with the solvent may be performed at 50 to 90 ° C for 60 to 300 minutes, for example, at 60 to 80 ° C for 180 to 240 minutes.

On the other hand, it is possible to further remove the foreign substances (e.g., silica, iron, etc.) contained in the mixture before putting the titanium dioxide described below into the mixture. The removal of the foreign materials can be performed by a conventionally known method, and the purity of the inorganic particles can be increased by removing the foreign matter.

Next, titanium dioxide is added to the mixture to prepare a suspension. The suspension may be prepared by a conventional method.

The solids content of the suspension may be from 4 to 15% by weight. When the solid content of the suspension is out of the above range, it is difficult to secure economical efficiency because the solid content is low at 4 wt% or less, and when the solid content is higher than 15 wt%, the viscosity is increased, .

Then, a carbon dioxide-containing gas is added to the suspension to react. The carbon dioxide-containing gas may be, for example, a mixed gas of carbon dioxide (CO ₂ ) and nitrogen (N ₂ ).

The content (concentration) of carbon dioxide contained in the gas may be 10 to 50% by concentration. 10, the carbon dioxide content of up to a concentration% because the reactivity for a long time is required to off the end of the reaction mothamyeo advantageous in economical efficiency, 50 concentration% or more of CO ₂ is added to the cost the so CO ₂ material secured via a separate collection process than the typical exhaust gas is This can also be economically disadvantageous.

The reaction of the suspension with the carbon dioxide-containing gas may be carried out at 60 to 90 ° C, for example at 70 to 80 ° C.

Next, the pH of the reaction product obtained by the reaction is stabilized. Specifically, the carbon dioxide-containing gas is added to the suspension to cause the reaction to proceed until the pH of the suspension is lowered to 9 or less and the pH of the reactant is not lowered to a stabilized state. At this time, the pH of the reactant reaching the stabilized state may be about 7.5.

Thereafter, when the reactant reaches a stabilized state in which the pH does not fall, the introduction of the carbon dioxide-containing gas is stopped, and the reaction is terminated, whereby inorganic particles including titanium dioxide, calcium carbonate and magnesium carbonate can be produced.

Such a method for producing an inorganic particle of the present invention can easily produce inorganic particles without special manufacturing facilities. Therefore, the present invention can increase the production efficiency of the inorganic particles. Further, even if the amount of titanium dioxide used is reduced, it is possible to manufacture inorganic particles capable of enhancing the appearance and hiding power of the coating film, thereby ensuring economical efficiency.

Hereinafter, the present invention will be described in detail with reference to examples.

However, the following examples are illustrative of the present invention, and the present invention is not limited by the following examples.

[ Example  One]

Mixtures of 9.6 g (CaO 59 wt%, MgO 41 wt%) and 200 g of water were mixed and reacted at 80 for 200 min to prepare a mixture containing calcium hydroxide and magnesium hydroxide.

Next, foreign substances such as silica and iron components present in the mixture were removed and separated using a 100 mesh net.

Next, 4 g of titanium dioxide (Chemorous R-706) of rutile crystal with an average particle size of 300 nm was added to the mixture containing calcium hydroxide and magnesium hydroxide to prepare a suspension having a solid content of 7% by weight Respectively.

Next, a 33% CO ₂ -containing gas mixed with 50 cc / min of CO _{2 and} 100 cc / min of N ₂ was added to the suspension (an aqueous solution containing a mixture of titanium dioxide, calcium hydroxide and magnesium hydroxide) heated to 80 ° C And the reaction was carried out.

Thereafter, the pH of the reactant (reaction solution) was lowered to 9 or lower and the pH was kept at a pH of 7.5, which was no longer lowered. The introduction of the 33% CO ₂ -containing gas was terminated and the reaction was terminated to form calcium and magnesium mixed carbonate To prepare inorganic particles.

[ Example  2]

Inorganic particles were prepared in the same manner as in Example 1, except that 8.0 g of reagent-grade CaO was added to 2.4 g of the lightweight dolomite fine powder having the composition of Example 1.

[ Example  3]

Inorganic particles were prepared in the same manner as in Example 1, except that 5.3 g of reagent-grade CaO was added to 4.9 g of the lightweight dolomite fine powder having the composition of Example 1.

[ Example  4]

An inorganic particle was prepared in the same manner as in Example 1, except that 2.0 g of reagent grade MgO was added to 7.3 g of the calcined dolomite fine powder having the composition of Example 1

[ Comparative Example  One]

Inorganic particles were prepared in the same manner as in Example 1, except that 10.78 g of reagent-grade CaO was added instead of the calcite dolomite fine particles in Example 1.

[ Comparative Example  2]

Inorganic particles were prepared in the same manner as in Example 1, except that 5.8 g of reagent grade MgO was added to 2.8 g of a lightweight dolomite fine powder having the composition of Example 1.

[ Comparative Example  3]

Inorganic particles were prepared in the same manner as in Example 1, except that 10.3 g of reagent grade CaO was added to 0.05 g of the calcite dolomite fine powder having the composition of Example 1.

[ Experimental Example  One]

The inorganic particles prepared in Example 1 were confirmed with a scanning electron microscope (SEM, Rkgaku SmartLab) and a transmission electron microscope (TEM, JEOL JEM-2100F) in order to confirm whether or not inorganic particles were formed. Respectively.

Referring to FIG. 1, it can be confirmed that the formation of the inorganic particles to which titanium dioxide, calcium carbonate and magnesium carbonate (hydro-magneite) are bonded is well formed. Specifically, referring to FIG. 2, it can be confirmed that inorganic particles in the form of a complex agglomerate in which magnesium carbonate (hydro-magneite) is enclosed in a solid in which titanium dioxide and calcium carbonate are combined are formed.

[ Experimental Example  2]

In order to confirm the crystal phase of the inorganic particles, the inorganic particles prepared in Example 1 were subjected to X-ray diffraction analysis (XRD, Quanta 3D FEG) and the results are shown in FIG.

Referring to FIG. 3, it can be seen that inorganic particles in which titanium dioxide on Rutile crystal, calcium carbonate on calcite and aragonite crystal, and magnesium carbonate on hydromagnesite crystal are formed are formed.

[ Experimental Example  3]

The compositions of the inorganic particles prepared in Examples and Comparative Examples were analyzed by X-ray diffraction analysis (XRD, Quanta 3D FEG), and a coating film was formed thereon to evaluate the concealment rate and appearance (gloss) The results are shown in Table 1 below. 8.4 g of water, 30 g of acrylic resin, and 3.6 g of inorganic particles were placed in a container, and the mixture was stirred for 30 minutes to a concealed hull and dried at room temperature for 12 hours.

division Compound composition weight (wt%) Concealment rate (%) Glossiness Calcium carbonate
(CaCO ₃₎ Magnesium carbonate
(Mg ₅ (CO ₃ ) ₄ (OH) ₂ .4H ₂ O) Titanium dioxide
(TiO ₂ ) Example 1 43.5 39.3 17.2 49.8 ○ Example 2 72.8 10.0 17.2 43.9 ○ Example 3 62.8 20.0 17.2 45.6 ○ Example 4 32.9 49.9 17.2 51.1 ○ Comparative Example 1 82.8 0 17.2 36.2 ○ Comparative Example 2 12.9 69.9 17.2 45.5
(Reduced film gloss) X Comparative Example 3 79.8 5.6 14.5 35 ○ - Concealment rate (degree of ability to cover the substrate during coating formation) = Concealed refuse Reflection / Concealment of black surface Reflection of white surface
- Gloss level = measurement of gloss occurrence with naked eyes

Referring to Table 1, it can be seen that in Examples 1 to 4 in which the mixing ratio (mixing ratio) of titanium dioxide, calcium carbonate, and magnesium carbonate is within the range of the present invention, the degree of concealment is high along with the glossiness.

On the other hand, Comparative Example 1, in which magnesium carbonate was not bonded, markedly lowered the concealment rate, and Comparative Examples 2 and 3 in which the mixing ratio of titanium dioxide, calcium carbonate and magnesium carbonate was outside the range of the present invention, Can be confirmed.

Claims (6)

Titanium dioxide, calcium carbonate, and magnesium carbonate,
Wherein the mixing ratio of the titanium dioxide, the calcium carbonate, and the magnesium carbonate is 1: 1 to 5: 0.5 to 3.
The method according to claim 1,
Wherein the magnesium carbonate is hydro-magne- site.
Reacting a calcium and magnesium containing raw material with a solvent to prepare a mixture containing calcium hydroxide and magnesium hydroxide,
Adding titanium dioxide to the mixture to prepare a suspension,
Adding a carbon dioxide-containing gas to the suspension to cause reaction; and
And stabilizing the pH of the reactant obtained by the reaction.
The method of claim 3,
The calcium and magnesium containing material is gyeongso dolomite (CaO · MgO), magnesium (MgO) and calcium oxide (CaO), magnesium hydroxide (Mg (OH) _2), calcium hydroxide (Ca (OH) ₂₎ from the group consisting of selected Wherein the inorganic particles are at least one kind of inorganic particles.
The method of claim 3,
Further comprising removing foreign matter contained in the mixture before the titanium dioxide is introduced.
The method of claim 3,
Wherein the content of carbon dioxide contained in the gas is 10 to 50% by weight.

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