Method for producing synthetic hydrotalcite and polyurethane fiber using the same

Abstract

An object of the present invention is to produce a large amount of synthetic huntite fine particles with a higher whiteness, higher purity, and a maximum particle diameter of 1 micrometer or less at a low cost compared to the prior art. 【Means for Solving the Problem】 The present invention relates to a huntite mineral having a structural formula of Mg3Ca(CO3)4, and prepares a cation precursor raw material containing magnesium ions and calcium ions in a molar ratio of 3:1, and CO3 2- A step of preparing an anion precursor raw material containing ions; a step of mixing the precursor raw materials to obtain a hydrated huntite crystal precipitate; a step of washing the hydrated huntite crystal precipitate; a step of drying the washed hydrated huntite crystal precipitate; a step of heat-treating to remove the crystallization water in the dried hydrated huntite crystal precipitate; a step of crushing the heat-treated huntite crystals; and a step of surface-treating the crushed huntite crystal particles; A manufacturing method of synthetic huntite fine particles having a whiteness of 80% or more, a purity of 95% or more, and a maximum particle diameter of 1 μm or less, and a polyurethane fiber containing the huntite fine particles containing the same are provided.

Description

Technical Field

[0001] The present invention relates to the production of synthetic hydrotalcite fine particles and polyurethane fibers using the same.

Background Art

[0002] As a method for obtaining hydrotalcite having a maximum particle diameter (D 100 ) of 2 micrometers or less from natural hydrotalcite mineral raw stones, mainly various pulverization devices that use a large amount of energy such as a mineral quarrying process - a coarse pulverization process - a fine pulverization process, a coarse pulverizer, a pin mill, a sand mill, an attrition mill, etc. must be used. At present, it is difficult to obtain pure hydrotalcite fine particles due to the mixing of impurities such as the mixing of the pulverization medium generated during pulverization each time through each pulverization process. In addition, in the case of natural hydrotalcite particles obtained through a mechanical pulverization process, the color of the particles varies greatly between lots due to the color of the hydrotalcite ore raw material depending on the production area. Further, in Patent Document 1, not only a large amount of energy is consumed, such as requiring a high heat treatment at 400 to 450°C, but it is not easy to obtain high-quality hydrotalcite due to reasons such as the mixing of foreign substances during the pulverization process. For these reasons, there is a very high industrial demand for synthetic hydrotalcite having a high whiteness, a high purity, and a size with a maximum particle diameter (D 100 ) of 2 micrometers or less.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The object of the present invention is to produce a large amount of synthetic hydrotalcite fine particles having a higher whiteness, higher purity, and a maximum particle diameter of 1 micrometer or less at a low cost as compared with the prior art.

[0005] Further, the object of the present invention is to provide a polyurethane (spandex) fiber containing the synthetic hydrotalcite fine particles.

Means for Solving the Problems

[0006] As a result of continuous research for several years in order to produce hydrotalcite that meets such industrial needs, the inventors of the present application have found that "synthetic hydrotalcite having a high whiteness and purity and a size with a maximum particle diameter (D 100 ) of 1 micrometer or less" can be synthesized, and the problems of whiteness, purity, and particle diameter derived from conventional natural hydrotalcite minerals can be solved.

[0007] The present invention provides a step of preparing a cation precursor raw material containing magnesium ions and calcium ions in a molar ratio of 3:1, and preparing an anion precursor raw material containing CO3 2- ions; a step of mixing the precursor raw materials to obtain a hydrated hydrotalcite crystal precipitate; a step of washing the hydrated hydrotalcite crystal precipitate; a step of drying the washed hydrated hydrotalcite crystal precipitate; a step of heat-treating to remove the crystallization water in the dried hydrated hydrotalcite crystal precipitate; a step of crushing the heat-treated hydrotalcite crystals; and a step of surface-treating the crushed hydrotalcite crystal particles; to provide a method for producing synthetic hydrotalcite fine particles having a whiteness of 80% or more, a purity of 95% or more, and a maximum particle diameter of 1 μm or less.

[0008] In addition, the raw material of magnesium ions is characterized by being dolomite, magnesite, magnesium oxide, magnesium chloride, magnesium nitrate, magnesium silicate, magnesium hydroxide, or hydro-magnesite, and the raw material of calcium ions is characterized by being dolomite, calcium carbonate, calcium hydroxide, calcium oxide, calcium chloride, or calcium nitrate, and CO3 2- The raw material of the anion is characterized by being sodium carbonate, sodium hydrogen carbonate, ammonium carbonate, ammonium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, or carbonate ions water obtained by hydrating carbon dioxide gas.

[0009] Furthermore, the mixed solution is characterized by having a pH of 9 to 11.

[0010] In addition, the synthetic hydrotalcite precipitate is washed, and the concentration of adsorbed water in the synthetic hydrotalcite obtained through a drying process at 100 to 120°C is characterized by being 0.5% or less.

[0011] In addition, the concentration of crystal water in the synthetic hydrotalcite obtained by heat-treating the synthetic hydrotalcite dried product at 250 to 300°C is characterized by being 1% or less.

[0012] Furthermore, after the heat treatment of the synthetic hydrotalcite, the content of MgO during XRF analysis is characterized by being 32 to 36% by weight, and the content of CaO is 14 to 18% by weight.

[0013] In addition, it is characterized by manufacturing polyurethane fibers containing hydrotalcite fine particles manufactured by the above manufacturing method.

Advantages of the Invention

[0014] According to the present invention, synthetic hydrotalcite fine particles having a higher whiteness, higher purity, and a maximum particle diameter of 1 micrometer or less than before can be manufactured in large quantities at low cost.

[0015] Furthermore, an object of the present invention is to provide a polyurethane (spandex) fiber containing the above synthetic hydrotalcite fine particles.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0017] Dolomite particles with an average particle size of 1 to 3 mm were obtained from a domestic dolomite (CaMg(CO3)2) mine. After dissolving this in 10 wt% nitric acid to form a solution, 2 mol of magnesium nitrate was added to this solution so that the ionic concentration of the total solution was 3 mol Mg 2+ , 1 mol Ca 2+ A mixed solution was prepared, and 4 mol CO3 2- ions corresponding to the above mixed cation solution were introduced to obtain a precipitate. The precipitate thus obtained was washed with ion-exchanged water and dried, and adsorbed water and crystallization water were removed at a temperature between 200 and 250 °C. After being micronized using a jet mill or the like, it was surface-treated with a fatty acid or a titanium coupling agent or the like, and finally, it can be applied as a raw material for manufacturing polyurethane fibers.

[0018] In the production of synthetic hydrotalcite, which can replace hydrotalcite - hydro magnesite, a natural mineral used for the adsorption of chloride ions in polyurethane fibers, the most important thing is the ratio of magnesium ions, calcium ions, and carbonate ions. According to the hydrotalcite structural formula (Mg3Ca(CO3)4), [Mg]:[Ca]:[CO3] = 3:1:4. In order to achieve such a ratio, it is necessary to use the purest raw materials for each component and meet the accurate synthesis conditions so that the coprecipitation reaction occurs well.

[0019] The inventors of the present application have been earnestly focusing on such points and conducting experiments. As a result, synthetic hydrotalcite fine particles with good whiteness, high purity, excellent chloride ion adsorption ability, and a maximum particle diameter of 1 micrometer or less have been synthesized, and a method for utilizing them in the production of polyurethane fibers will be described in more detail. However, the present invention is not limited to what is described in this detailed description.

[0020] The magnesium raw material used as a raw material in the present invention may be dolomite, magnesite, magnesium oxide, magnesium chloride, magnesium nitrate, magnesium silicate, magnesium hydroxide, or hydro magnesite. The calcium ion raw material may be dolomite, calcium carbonate, calcium hydroxide, calcium oxide, calcium chloride, or calcium nitrate, etc., as long as it can be used, and in particular, it may be a compound raw material that can be made into a transparent aqueous solution using inorganic acids such as hydrochloric acid and nitric acid, and is not limited to a specific raw material. Also, the carbonate ion raw material that can supply carbonate ions may be sodium carbonate, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, potassium carbonate, potassium bicarbonate, or a substance that can supply carbonate ions obtained by hydrating carbon dioxide gas, and is not limited to a specific raw material. 1. Synthesis of hydrotalcite crystals

[0021] A mixed aqueous solution containing 3 mol of magnesium raw material and 1 mol of calcium raw material, and 4 mol of carbonate anions (CO3 2-)After manufacturing the aqueous solutions of ions respectively, a certain amount of pure water was added in advance to a reactor equipped with a stirrer and stirred. Then, the two types of aqueous solutions were introduced into the reactor at a rate of 100 mL / min through a metering pump, so that huntite hydrate (Mg3Ca(CO3)4·nH2O) can be synthesized. The mixed solution is characterized by a pH of 9 to 11.

[0022] Unnecessary ion species were removed from the thus synthesized huntite hydrate (Mg3Ca(CO3)4·nH2O) through a washing process, and the washed huntite hydrate (Mg3Ca(CO3)4·nH2O) can be obtained. Also, by drying this at 100 to 120 °C to remove the moisture adsorbed on the surface of the particles, dried huntite hydrate (Mg3Ca(CO3)4·nH2O) can be obtained. At this time, the concentration of adsorbed water was 0.5%. Then, in order to remove the water of crystallization in the huntite hydrate (Mg3Ca(CO3)4·nH2O), through a heat treatment process at 250 to 300 °C, finally huntite crystals (Mg3Ca(CO3)4) with the water of crystallization removed were obtained. At this time, the concentration of the water of crystallization was 1% or less.

[0023] After that, the obtained huntite crystals (Mg3Ca(CO3)4) were identified by X-ray diffraction analysis (XRD), and it was found that they have the same crystal structure as natural huntite (Mg3Ca(CO3)4). As a result of XRF analysis, it was found that the content of MgO was 32 to 36 wt% and the content of CaO was 14 to 18 wt%. 2. Crushing process

[0024] From the huntite crystals synthesized in this way, agglomerate-free huntite crystals can be obtained through a crushing process using a jet mill or the like as an agglomerate. The maximum particle diameter (D 100 ) of the particles of the huntite crystals obtained by this crushing process was 1 micrometer or less. At this time, a laser diffraction particle size analyzer was used as the analytical instrument.

[0025] 3. Surface treatment

[0026] In order to hydrophobize the surface of the crushed huntite crystal particles, fatty acids and titanate coupling agents can be mainly used. Among the surface treatment agents used at this time, those containing C8 to C 26 Saturated fatty acids such as caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, or cerotic acid, and myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, or unsaturated fatty acids such as linoleic acid can be used, and these can be used in combination. In addition, as compounds that can be used as surface treatment agents, monoalkoxy titanates, oxyacetate chelate titanates, A,B ethylene chelate titanates, or titanate coupling agents such as quat titanates, which are excellent in reaction with carbonates, can be used.

[0027] Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the present invention is not limited thereto. Example 1

[0028] 184.3 g of dolomite particles (manufactured by Sanbo Mining Co., Ltd.) having the formula [[CaMg(CO3)2]] and a particle size of 1 to 2 mm were slowly dissolved using a 2N nitric acid solution without undergoing an additional grinding process. Trace amounts of insoluble impurities such as Si were removed through a filtration process. After that, 500 g of the primary reaction solution was prepared in a 2-liter Erlenmeyer flask. Then, 296.62 g of magnesium nitrate salt (Mg(NO3)2) was added to the primary reaction solution, and while dissolving, the volume of the total aqueous solution was adjusted to 1,000 mL to obtain a secondary reaction raw material.

[0029] Also, 423.93 g of sodium carbonate was weighed into another 2-liter Erlenmeyer flask container. While adding pure water to this container and shaking well, the total aqueous solution dosage was adjusted to 1,000 mL to obtain a secondary reaction raw material.

[0030] Next, 1,000 mL of pure water was previously placed in another 5-liter four-necked round-bottom flask equipped with a stirrer. While gradually stirring, a metering pump was installed in the solution containing Mg and Ca ions so that it could be quantitatively introduced into the 5-liter round-bottom flask. Also, the solution containing CO3 ions was prepared in the same way. <Reaction Scheme 1> 3 mol Mg(NO3)2 + 1 mol Ca(NO3)2 + 4 mol Na2CO3 → Mg3Ca(CO3)4·nH2O + 8NaNO3 (1)

[0031] As can be seen from reaction scheme (1), this reaction is an irreversible reaction, and it was possible to easily synthesize huntite crystals containing crystal water. The thus-synthesized huntite crystals were further subjected to drying, heat treatment, and crushing processes to obtain synthesized huntite crystals with an average particle size of 0.33 micrometers and a maximum particle size of 0.95 micrometers.

[0032] The electron micrograph and particle size distribution data of the synthesized huntite after the washing, drying, and heat treatment processes were the same as those in Figure 2.

[0033] Fatty acids were used to make the surface of the hantite particles hydrophobic. That is, 300 g of a solution in which 50 g of stearic acid had been previously dissolved was prepared. 1 kg of synthetic hantite crystal particles was placed in a Henschel mixer equipped with a heating device with an internal volume of 3 liters, and while slowly stirring at a stirring speed of 200 rpm, the previously prepared fatty acid solution was sprayed into the Henschel mixer using a spray gun. Thereafter, the heating device in the Henschel mixer was operated to maintain a temperature of 90°C, and the hantite crystals were dried by holding for 1 hour. At this time, the contact angle of the obtained hantite crystal particles with respect to water was 133.28°. The change in the contact angle before and after the surface treatment is shown in Figure 3. Example 2

[0034] In Example 1, a 2N hydrochloric acid solution was used instead of the 2N nitric acid solution, and all other details were carried out in the same manner. Through such a series of steps, synthetic hantite crystals with an average particle diameter of 0.25 micrometers and a maximum particle diameter of 0.92 micrometers could be obtained. Also, for the surface treatment of the hantite crystal particles, the treatment was carried out in the same manner as in Example 1. At this time, the contact angle of the obtained hantite crystal particles with respect to water was 120°. Example 3

[0035] For the surface treatment of the synthetic hydrotalcite crystal particles obtained in Example 1, monoalkoxy titanates were used. That is, 50 g of monoalkoxy titanates was diluted with ethyl alcohol to make the total volume 300 g. 1 kg of synthetic hydrotalcite crystal particles were placed in a Henschel mixer equipped with a heating device with an internal volume of 3 liters, and while slowly stirring at a stirring speed of 200 rpm, the pre-prepared monoalkoxy titanates-ethyl alcohol solution was sprayed into the Henschel mixer using a spray gun. After that, the heating device in the Henschel mixer was operated to maintain a temperature of 90 °C, and the mixture was held for 1 hour to produce dried hydrotalcite crystals. At this time, the contact angle of the obtained hydrotalcite crystal particles with respect to water was 130°.

Claims

1. Prepare a cation precursor raw material containing magnesium ions and calcium ions in a molar ratio of 3:1, and CO ３ ２－ A step of preparing an anion precursor raw material containing ions; A step of mixing the precursor raw materials to obtain a hydrated huntite crystal precipitate; A step of washing the hydrated huntite crystal precipitate; A step of drying the washed hydrated huntite crystal precipitate; A step of heat-treating to remove the water of crystallization in the dried hydrated huntite crystal precipitate; A step of crushing the heat-treated huntite crystals; and A step of surface-treating the crushed huntite crystal particles; A method for producing synthetic huntite fine particles having a whiteness of 80% or more, a purity of 95% or more, and a maximum particle size of 1 μm or less, comprising the above steps.

2. The method for producing huntite fine particles according to claim 1, wherein the raw material of magnesium ions is at least one of dolomite, magnesite, magnesium oxide, magnesium chloride, magnesium nitrate, magnesium silicate, magnesium hydroxide, and hydrotalcite.

3. The method for producing huntite fine particles according to claim 1, wherein the raw material of calcium ions is at least one of dolomite, calcium carbonate, calcium hydroxide, calcium oxide, calcium chloride, and calcium nitrate.

4. CO ３ ２－ The method for producing huntite fine particles according to claim 1, wherein the raw material of the anion is carbonate ion water obtained by hydrating at least one of sodium carbonate, sodium hydrogen carbonate, ammonium carbonate, ammonium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, and carbon dioxide gas.

5. The method for producing huntite fine particles according to claim 1, wherein the mixed solution has a pH of 9 to 11.

6. The method for producing huntite fine particles according to claim 1, wherein the adsorbed water concentration of the synthetic huntite obtained through a drying process at 100 to 120 °C after washing the synthetic huntite precipitate is 0.5% or less.

7. The method for producing huntite fine particles according to claim 1, wherein the water of crystallization concentration of the synthetic huntite obtained by heat-treating the synthetic huntite dried product at 250 to 300 °C is 1% or less.

8. The method for producing huntite fine particles according to claim 1, wherein after heat-treating the synthetic huntite, the MgO content during XRF analysis is 32 to 36% by weight, and the CaO content is 14 to 18% by weight.

9. A polyurethane fiber containing huntite fine particles produced by the method according to any one of claims 1 to 8.

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