WO2022031031A1

WO2022031031A1 - Magnesium silicate and method for preparing same

Info

Publication number: WO2022031031A1
Application number: PCT/KR2021/010265
Authority: WO
Inventors: 권기영; 표은지
Original assignee: 경상국립대학교산학협력단
Priority date: 2020-08-07
Filing date: 2021-08-04
Publication date: 2022-02-10
Also published as: KR20220018725A; KR102483599B1

Abstract

The present invention relates to a method for preparing spherical magnesium silicate, the method comprising the steps of: preparing a mixed solution by mixing an aqueous sodium silicate solution, a non-polar solvent, and a nonionic surfactant; adding dropwise a magnesium solution to the mixed solution while stirring, to synthesize magnesium silicate; and obtaining the synthesized magnesium silicate through filtration. According to the present application, spherical magnesium silicate can be prepared using a water in oil emulsion (w/o emulsion).

Description

Magnesium silicate and method for preparing same

The present invention relates to magnesium silicate and a method for preparing the same. Specifically, it is a method for producing magnesium silicate having a spherical shape using a water in oil emulsion.

Magnesium silicate has a composition of 2MgO·3SiO ₂ ·nH ₂ O (Mg ₂ Si ₃ O ₈ nH ₂ O) and is used as an adsorbent and antacid in various fields such as food and medicine in powder form.

Methods for synthesizing magnesium silicate include a precipitation method, a hot water precipitation method, and a mechano-chemical dehydration method. Among them, the precipitation method is to react a magnesium salt soluble in water and a soluble sodium silicate in an aqueous solution to precipitate magnesium silicate as an insoluble salt, isolate it, and then dry it to synthesize it. When such a method for synthesizing magnesium silicate is used, needle-shaped magnesium silicate is synthesized.

Recently, spherical magnesium silicate is required to improve characteristics such as adsorption power and filtration rate. In order to synthesize such spherical magnesium silicate, a spray drying method has been mainly used in the prior art.

[Prior art literature]

[Patent Literature]

(Patent Document 0001) Korean Patent Publication No. 10-0785089

The present application relates to a method for producing magnesium silicate for solving the problems of the prior art, and it is possible to prepare magnesium silicate having a spherical shape using a water in oil emulsion (w/o emulsion). .

The method for producing a spherical magnesium silicate of the present invention for achieving the above technical problem comprises the steps of preparing a mixed solution by mixing an aqueous sodium silicate solution, a non-polar solvent and a nonionic surfactant; synthesizing magnesium silicate by dropping the magnesium solution into the mixed solution while stirring; and filtering the synthesized magnesium silicate to obtain it.

Based on 100 parts by weight of the sodium silicate aqueous solution, 1 part by weight to 10 parts by weight of the non-polar solvent and 0.5 parts by weight to 5 parts by weight of the nonionic surfactant may be mixed, but is not limited thereto.

The step of dropping the magnesium solution may be dropping at a rate of 5 ml/min to 10 ml/min, but is not limited thereto.

The non-polar solvent may include a material selected from the group consisting of xylene, hexane, benzene, toluene, styrene, mesitylene, pentane, dodecane, heptane, and combinations thereof, but is not limited thereto no.

The magnesium solution may include a material selected from the group consisting of magnesium sulfate, magnesium hydroxide, magnesium chloride, magnesium nitrate, and combinations thereof, but is not limited thereto.

The step of synthesizing the magnesium silicate may be performed at a temperature of 70° C. to 150° C., but is not limited thereto.

The present invention relates to a spherical magnesium silicate produced by the method for producing magnesium silicate.

The diameter of the spherical magnesium silicate may be 1 μm to 3 μm, but is not limited thereto.

The spherical magnesium silicate may have a CPR of 20 to 30, but is not limited thereto.

The filtration rate of the spherical magnesium silicate may be 1.8 g/s to 5 g/s, but is not limited thereto.

The above-described problem solving means are merely exemplary, and should not be construed as limiting the present application. In addition to the exemplary embodiments described above, additional embodiments may exist in the drawings and detailed description.

The disclosed technology may have the following effects. However, this does not mean that a specific embodiment should include all of the following effects or only the following effects, so the scope of the disclosed technology should not be understood as being limited thereby.

According to the above-described means for solving the problems of the present application, the method for producing magnesium silicate according to the present application may use a water in oil emulsion (w/o emulsion) to prepare magnesium silicate having a spherical shape. In particular, it is easier to control the size of magnesium silicate compared to the conventional spray drying method used to prepare spherical magnesium silicate.

The adsorption capacity of the magnesium silicate of the present application was 1.2 times superior to that of the conventional non-spherical (needle-shaped, etc.) magnesium silicate. In addition, in terms of filtration speed, it shows a 35% improvement compared to the conventional magnesium silicate.

1 is a flowchart of a method for producing magnesium silicate according to an embodiment of the present application.

2 is a scanning electron microscope (SEM) photograph of magnesium silicate prepared according to an embodiment of the present application.

3 is a scanning electron microscope (SEM) photograph of magnesium silicate prepared according to an embodiment of the present application.

4 is a scanning electron microscope (SEM) photograph of magnesium silicate prepared according to Comparative Example of the present application.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and will be described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

In describing each figure, like reference numerals are used for like elements. Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. The term “and/or” includes a combination of a plurality of related listed items or any of a plurality of related listed items.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in commonly used dictionaries should be interpreted as having meanings consistent with the meanings in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. shouldn't

Throughout this specification, when a member is positioned “on”, “on”, “on”, “on”, “under”, “under”, or “under” another member, this means that a member is positioned on the other member. It includes not only the case where they are in contact, but also the case where another member exists between two members.

Throughout this specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

As used herein, the terms "about," "substantially," and the like are used in a sense at or close to the numerical value when the manufacturing and material tolerances inherent in the stated meaning are presented, and to aid in the understanding of the present application. It is used to prevent an unconscionable infringer from using the mentioned disclosure in an unreasonable way. Also, throughout this specification, "step to" or "step to" does not mean "step for".

Throughout this specification, the term "combination of these" included in the expression of the Markush form means one or more mixtures or combinations selected from the group consisting of the components described in the expression of the Markush form, and the components It is meant to include one or more selected from the group consisting of.

Throughout this specification, reference to “A and/or B” means “A or B”, or “A and B”.

Hereinafter, the spherical magnesium silicate of the present application and a method for manufacturing the same will be described in detail with reference to embodiments, examples, and drawings. However, the present application is not limited to these embodiments and examples and drawings.

The present application includes the steps of preparing a mixed solution by mixing an aqueous sodium silicate solution, a non-polar solvent and a nonionic surfactant; synthesizing magnesium silicate by dropping the magnesium solution into the mixed solution while stirring; and filtering the synthesized magnesium silicate to obtain a spherical magnesium silicate.

First, a mixed solution is prepared by mixing an aqueous sodium silicate solution, a non-polar solvent, and a nonionic surfactant (S100).

When using less than 1 part by weight or more than 10 parts by weight of the non-polar solvent and less than 0.5 parts by weight or more than 5 parts by weight of the non-ionic surfactant based on 100 parts by weight of the sodium silicate aqueous solution, sodium silicate may not be properly synthesized .

More preferably, 2 to 5 parts by weight of the non-polar solvent may be mixed based on 100 parts by weight of the sodium silicate aqueous solution. At this time, by using 1/20 or less of the non-polar solvent compared to the sodium silicate, a water in oil emulsion (w/o emulsion) can be prepared under conditions of minimizing the amount of oil.

The non-polar solvent is not limited to the above-mentioned solvents, and in addition, various cyclic hydrocarbons, chain hydrocarbons, etc. may be used as the non-polar solvent.

The nonionic surfactant may include a material selected from the group consisting of polyoxyethylene alkyl ether, fatty acid sorbitan ester, fatty acid diethanolamine, alkyl monoglyceryl ether, and combinations thereof, but is limited thereto no.

When the nonionic surfactant is not used, the aqueous solution of sodium silicate and the non-polar solvent are separated from each other to prepare a water-in-oil emulsion.

Then, the magnesium solution is added dropwise to the mixed solution while stirring to synthesize magnesium silicate (S200).

The magnesium solution may be dropped into the mixed solution, but on the contrary, the mixed solution may be added dropwise to the magnesium solution.

The stirring may be stirring at 100 rpm to 500 rpm, but is not limited thereto.

The size of the magnesium silicate may be controlled by adjusting the dropping rate, amount, concentration and the stirring rate of the magnesium solution.

Compared to the conventional spray drying method used to prepare spherical magnesium silicate, it is easier to control the size of the magnesium silicate.

The faster the stirring speed, the smaller the size of the magnesium silicate.

When the temperature is less than 70 °C in the step of synthesizing the magnesium silicate, the magnesium silicate may not be sufficiently synthesized, and when the temperature is higher than 150 °C, the physical properties of the magnesium silicate may be reduced.

The present application relates to a spherical magnesium silicate produced by the method for producing magnesium silicate.

The adsorption capacity of the spherical magnesium silicate was 1.2 times superior to that of the conventional non-spherical (acicular type, etc.) magnesium silicate. In addition, in terms of filtration speed, it shows a 35% improvement compared to the conventional magnesium silicate.

The CPR (Controlled Polymerization Rate) is an index indicating the amount of basic substances in the composition, and is a result of quantifying the amount of neutralized and titrated hydrochloric acid after mixing the composition (polyol) with methanol. In the present application, a polyol obtained through a polyol purification experiment using the magnesium silicate was used as the composition. As the CPR of the polyol is lower, the physical properties of a polyurethane that can be prepared using the polyol may be improved, and the CPR value may be lowered as impurities in the polyol composition are effectively removed.

The filtration rate is determined by measuring the time from the time the first drop falls after pouring all the polyol purified using the magnesium silicate into the Buchner funnel until all the polyol passes through the filter paper to determine 'mass of polyol/filtration time ' can be expressed as

With respect to the spherical magnesium silicate of the present application, a detailed description of parts overlapping with the manufacturing method of magnesium silicate of the present application is omitted. The same can be applied to magnesium.

The present invention will be described in more detail through the following examples, but the following examples are for illustrative purposes only and are not intended to limit the scope of the present application.

[Example 1]

First, sodium silicate was diluted with water to prepare 47.7% sodium silicate aqueous solution. 20 ml of hexane and 6 g of a nonionic surfactant were added to 283 g of the 47.7% sodium silicate aqueous solution and stirred at a speed of 4000 rpm to prepare a mixed solution (w/o emulsion).

Then, 82.2 g of magnesium sulfate was dissolved in 160 g of water to prepare a magnesium solution.

Then, magnesium silicate was synthesized by adding the magnesium solution to the mixed solution at a rate of 10 ml/min while stirring at a temperature of 100° C. at 150 rpm.

After the magnesium silicate was filtered, spherical magnesium silicate was obtained through washing and drying.

[Example 2]

A spherical magnesium silicate was obtained in the same manner as in Example 1, except that xylene, not hexane, was used.

[Comparative Example 1]

A needle-shaped magnesium silicate was obtained in the same manner as in Example 1, except that hexane and a nonionic surfactant were not added.

1. 구형의 규산 마그네슘의 특성 평가 1. Characterization of spherical magnesium silicate

The properties of the magnesium silicate prepared in Examples 1 and 2 and Comparative Example 1 were analyzed, and are shown as FIGS. 2 to 4 .

Specifically, FIG. 2 is a scanning electron microscope (SEM) photograph of the magnesium silicate prepared in Example 1. Referring to FIG.

Specifically, FIG. 3 is a scanning electron microscope (SEM) photograph of the magnesium silicate prepared in Example 2 above.

Specifically, FIG. 4 is a scanning electron microscope (SEM) photograph of the magnesium silicate prepared in Comparative Example 1. Referring to FIG.

According to the results shown in FIGS. 2 and 3 , it can be seen that the magnesium silicate prepared according to an embodiment of the present application is synthesized in a spherical shape, and the particles are uniformly distributed throughout.

In addition, it was found that the size (diameter) of the magnesium silicate in FIG. 2 was about 1.5 μm, and the size (diameter) of the magnesium silicate in FIG. 3 was 2 μm.

According to the results shown in FIG. 4 , it can be confirmed that the needle-shaped magnesium silicate prepared according to the comparative example was synthesized in a non-spherical form without uneven particle size. In addition, the size of the magnesium silicate of Comparative Example 1 was 30 μm to 200 μm, which was larger than that of Examples 1 and 2.

2. 규산 마그네슘의 폴리올 정제능력 평가2. Evaluation of Polyol Refining Ability of Magnesium Silicate

[Experimental Example 1]

5 g of the magnesium silicate prepared in Example 1 was put into a heat-drying moisture meter in order to minimize the weight error in the evaluation of refining ability, and dried until the moisture content was less than 2%.

Then, 300 g of polyol, 3 ml of water, and 3 g of the dried magnesium silicate were placed in a 500 ml 3-neck round bottom flask, and the mixture was heated to 100° C. while stirring at 300 rpm. The mixture was stirred while maintaining at a temperature of 100° C. for 1 hour to purify the polyol.

In order to measure the filtration rate, 300 g of the purified polyol was poured into a Buchner funnel heated to a temperature of 80° C., and then the filtration time from the first drop to when all the polyol passed through the filter paper was 2 measured in minutes. That is, the filtration rate was measured to be 2.5 g/s.

In order to evaluate the purification ability, 5 g of the filtered polyol was diluted in 100 ml of methanol and then titrated with 0.005 N hydrochloric acid (HCl) to measure the appropriate amount with an automatic titrator. The CPR of the polyol purified using magnesium silicate prepared according to this Example was measured to be a value of 20 to 30.

[Experimental Example 2]

5 g of the magnesium silicate prepared in Comparative Example 1 was put into a heat-drying moisture meter in order to minimize the weight error in the evaluation of refining ability, and dried until the moisture content was less than 2%.

To measure the filtration rate, 300 g of the purified polyol was poured into a Buchner funnel heated to a temperature of 80° C., and then the filtration time from the first drop to when all the polyol passed through the filter paper was 3 measured in minutes. That is, the filtration rate was measured to be 1.67 g/s.

In order to evaluate the purification ability, 5 g of the filtered polyol was diluted in 100 ml of methanol and then titrated with 0.005 N hydrochloric acid (HCl) to measure the appropriate amount with an automatic titrator. The CPR of the polyol purified using magnesium silicate prepared according to this example was measured to be a value of 30 to 40.

According to the results shown in Experimental Examples 1 and 2, when compared to Comparative Example 1, the filtration rate of the spherical magnesium silicate prepared in Example 1 was improved by about 33%, and the CPR of the purified polyol was improved by about 33% can check that That is, it can be confirmed that properties such as filtration rate and CPR of the purified polyol of the spherical magnesium silicate prepared using the method for producing magnesium silicate of the present application are improved compared to the conventional non-spherical magnesium silicate.

The above description of the present application is for illustration, and those of ordinary skill in the art to which the present application pertains will understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present application. 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 application is indicated by the following claims rather than the above detailed description, 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 application.

Claims

preparing a mixed solution by mixing an aqueous sodium silicate solution, a non-polar solvent, and a nonionic surfactant;

synthesizing magnesium silicate by dropping the magnesium solution into the mixed solution while stirring; and

A method for producing a spherical magnesium silicate, including; obtaining by filtration of the synthesized magnesium silicate.
The method of claim 1,

Based on 100 parts by weight of the sodium silicate aqueous solution solution, 1 part by weight to 10 parts by weight of the non-polar solvent and 0.5 parts by weight to 5 parts by weight of the nonionic surfactant are mixed, a method for producing a spherical magnesium silicate.
The method of claim 1,

The dropping of the magnesium solution is a method for producing a spherical magnesium silicate that is dropped at a rate of 5 ml/min to 10 ml/min.
The method of claim 1,

The non-polar solvent includes a material selected from the group consisting of xylene, hexane, benzene, toluene, styrene, mesitylene, pentane, dodecane, heptane, and combinations thereof. Way.
The method of claim 1,

The method for producing a spherical magnesium silicate, wherein the magnesium solution contains a material selected from the group consisting of magnesium sulfate, magnesium hydroxide, magnesium chloride, magnesium nitrate, and combinations thereof.
The method of claim 1,

The step of synthesizing the magnesium silicate will be made under a temperature of 70 ℃ to 150 ℃, the method for producing a spherical magnesium silicate.
A spherical magnesium silicate produced by the method according to any one of claims 1 to 6.
8. The method of claim 7,

The diameter of the spherical magnesium silicate is 1 μm to 3 μm, the spherical magnesium silicate.
8. The method of claim 7,

The spherical magnesium silicate has a CPR of 20 to 30, a spherical magnesium silicate.
8. The method of claim 7,

The filtration rate of the spherical magnesium silicate is 1.8 g / s to 5 g / s, the spherical magnesium silicate.