KR100486669B1 - Method of synthesizing hydrotalcites - Google Patents

Abstract

In the present invention, the first metal hydroxide, the second metal hydroxide, and the interlayer anion supplying material are mixed with a water-soluble metal salt and a basic compound in an aqueous solution adjusted to a neutral or weakly alkaline state and then aged at a high temperature and a high pressure to form a hydrotalcite form To a method for producing a layered composite metal hydrate.

The layered composite metal hydrate prepared according to the present invention has greatly improved physical and chemical properties such as pyrolysis characteristics and thermal stability as compared with the layered composite metal hydrates which have been synthesized in the prior art and can greatly reduce the reaction time by improving the reaction activity In addition, by suppressing the generation of by-products, the washing water quantity can be greatly reduced.

Description

TECHNICAL FIELD The present invention relates to a method for producing a layered metal hydrate,

The present invention relates to a method for producing a layered composite metal hydrate, and more particularly to a method for producing a layered composite hydrate which can significantly improve the heat resistance of a halogenated resin.

Among polyolefin resins, halogenated resins and polyamide resins in particular, there are unstable heat, light and the like. Particularly when they are melted by heating in a molding process or when they are used at a high temperature, heat degradation or quality deterioration occurs. This results in disadvantages such as coloring, property change, or mechanical properties of the final molded product.

Particularly, halogenated resin molded articles are more unstable against heat, light and the like compared to other resin molded products. Therefore, in order to improve the stability, heavy metal fatty acid series (Pb, Cd, etc.), Sn series and Ba series Have been used in combination. However, recently, the toxicity of such stabilizers is a social and environmental problem, and development of Sn-based and Ca-Zn-based stabilizers has been concentrated.

Sn-based stabilizers not only have a limited amount of addition in view of toxicity but also have a high product cost. On the other hand, the Ca-Zn type stabilizer has the drawback that the toxicity thereof is extremely small and the cost is low, but the effect of improving the thermal stability is poor. In order to solve such a problem, a technique of using a composite metal hydroxide such as Mg-Al hydrotalcite or Li-Al hydrotalcite as a heat stabilizer has been proposed in some cases.

The hydrotalcite type composite metal hydrate refers to a layered complex hydroxide which is also referred to as an anionic clay, a layered double hydrate, or a layered mixed metal hydroxide. That is, the layered mixed metal hydroxide is a hydrotalcite type compound, which means a material having a structure in which an anion is fixed between a layer made of a mixed metal component and a hydroxyl group (OH ^- ) and a layer. Such hydrotalcite exists as a natural mineral in some areas, and a layered composite metal hydrate having a similar structure can be expressed by the following general formula.

[M (II) _1-x M (III) _x ] (OH) _n A ^{n -1} mH ² O

M (II) is a metal component capable of having an oxidation number of +2, and M (III) is a metal component constituting the center of the layer, and M (II) Which is a metal component. On the other hand, the (OH) component constitutes the upper and lower surfaces of the mixed metal component, and A is an interlayer anion which can be exchanged with another anion. x is the fraction of the M (II) component and the M (III) component. The overall charge amount of the hydrotalcite having the above structure is determined according to the fraction of the M (III) component, and is usually 0.20 <x <0.33.

Such layered composite metal hydrates are commercially synthesized at a high purity and are widely used as additives for removing environmental pollutants, catalyst deactivators, antacids, acid adsorbents, flame retardants, flame retardant auxiliaries and heat stabilizers for polymers, acidifiers, sunscreens, And so on.

Layered metal hydrates are broadly classified into coprecipitation using a water-soluble metal salt and hydrothermal synthesis using a poorly soluble metal hydrate at a high temperature.

U.S. Patent No. 3,879,523 discloses a method for producing a layered composite metal hydrate of a hydrotalcite structure using various mixed metal components and an anion supply material. In the above-mentioned U.S. Patent, the synthesis is carried out by coprecipitation using a water- There is a problem that excessive washing water is required in the reaction process and a large amount of by-products are generated.

On the other hand, U.S. Patent No. 4,458,026 discloses a solution in which a divalent metal inorganic salt such as magnesium nitrate and a trivalent metal inorganic salt such as aluminum nitrate are mixed with a solution in which sodium hydroxide and sodium carbonate as an anion supply material are stoichiometrically mixed To prepare a hydrotalcite slurry, which is then filtered, washed, and heated and dried at a temperature of about 300 to 600 ° C to produce a hydrotalcite-type catalyst. According to the method disclosed in the above US patent, a large amount of heat is consumed during the process.

In addition, in U.S. Patent No. 4,904,457, a magnesium compound such as magnesium carbonate or magnesium hydroxide is activated by heating at a high temperature and then activated magnesium is reacted with a solution containing an aluminum salt, a carbonate and a hydroxyl ion over a pH of 13 To a process for preparing hydrotalcites of high yield (> 75%). However, the process disclosed in the above-mentioned U.S. Patents not only consumes excessive energy but also reacts in a basic compound condition, whereby the thermal stability efficiency of hydrotalcite finally produced is greatly reduced.

In Korean Patent Laid-Open Publication No. 2001-0108920, a mixture of a crystalline metal hydroxide is dispersed in water, a mixture of a water-soluble metal hydroxide, an interlayer anion feed material and an alkali metal hydroxide solution are mixed, Discloses a method for producing a layered composite metal hydroxide of a decation type. The Korean patent discloses that the physical and chemical properties of the layered composite metal hydroxide can be controlled by using the advantages and disadvantages of the coprecipitation method and the hydrothermal synthesis method. However, since a water-soluble metal hydroxide is excessively used, many by-products are produced In addition, by reacting at a high pH, water pollution is induced and excessive washing is required.

Korean Patent Laid-Open Publication No. 2000-0049194 discloses a method for producing a composite metal hydroxide containing a lithium metal as a stabilizer for a halogen-containing resin. However, since it uses three metals and expensive lithium, .

Therefore, there is a need in the art for a method of manufacturing a layered composite metal hydrate capable of minimizing the generation of a water pollutant source by restricting the thermal stability efficiency of a finally produced layered metal hydrate through an inexpensive manufacturing process and suppressing the formation of by- .

It is an object of the present invention to provide a method for producing a layered composite metal hydrate in which an interlayer anion component having a greatly improved reaction yield and reaction activity is mixed.

It is another object of the present invention to provide a method for producing a layered composite metal hydrate capable of minimizing the generation of water pollutants by inhibiting the formation of by-products generated during the manufacturing process.

It is another object of the present invention to provide a layered composite metal hydrate capable of improving the thermal stability efficiency of a polymer material, particularly a halogen-containing resin.

Other objects, characteristics, etc. of the present invention will be described in more detail below.

The present invention relates to a method for producing a layered composite hydrate, the present invention comprises (a) a first metal hydroxide _{^{(M Ⅱ (OH) 2)}} , a second metal hydroxide (M ^Ⅲ (OH) ₃₎ and the interlayer anions feed material Mixing and dispersing the water-soluble metal salt and the basic compound in an aqueous solution adjusted to a pH ranging from 7 to 9; (b) reacting the aqueous solution in which the first metal hydroxide, the second metal hydroxide and the intercalating anion supplying material are mixed at a high temperature in the range of 170 to 220 ° C.

 Preferably, the step (b) may further include a step of surface-treating the layered composite metal hydrate at a temperature of 60 to 110 ° C.

In particular, in the step (a), the water-soluble metal salt and the basic compound may be added in an amount of 5 to 20 wt% based on the total amount of the first metal hydroxide and the second metal hydroxide, And more preferably at least one selected from aluminum chloride, aluminum nitrate, and aluminum sulfate.

On the other hand, the basic compound added to the reaction system together with the water-soluble metal salt is preferably a hydrate of an alkali metal such as sodium hydroxide or potassium hydroxide.

In addition, the interlayer anion supplying material that can be used in the present invention may include carbonate, sulphate, nitrate, and the like, and may be selected from at least one of carbonic acid, sodium carbonate, and sodium bicarbonate.

Hereinafter, the present invention will be described in more detail.

The present inventors have made efforts to improve the conventional problems of producing a layered composite metal hydrate in the hydrotalcite form. As a result, the present inventors have found that the pH of an aqueous solution in which a divalent and trivalent metal hydroxide and an intercalation anion supply material are mixed and dispersed is neutral Or weakly alkaline controlled layered metal hydrates have been found to improve thermal stability in polymeric materials, especially halogen-containing polymeric resins such as chlorine or bromine.

That is, according to the present invention, the first metal hydroxide (M ^II (OH) ₂ ) and the second metal hydroxide (M ^III (OH) ₃ ) are used as a raw material of mixed metal components constituting the center of the layered metal hydrate , Mixing the first metal hydroxide, the second metal hydroxide and the interlayer anion supplying material in an aqueous solution adjusted to a pH ranging from 7 to 9 by appropriately adjusting the amount of the water soluble metal salt and the basic compound so as to improve the reaction activity and the yield, It was aged at high temperature and high pressure to synthesize a layered composite metal hydrate with greatly improved thermal stability.

According to a preferred embodiment of the present invention, after the aging reaction at a high temperature and a high pressure, the surface is treated with a fatty acid in a lower temperature range than the aging reaction and subjected to a washing / filtration / drying process, Hydrates can be prepared.

Conventionally, when a layered complex hydrate is synthesized by a hydrothermal synthesis method, a first metal hydroxide, a second metal hydroxide and an intercalation anion supply material are mixed and reacted. In this case, the first metal hydroxide and the second metal hydroxide Is a poorly soluble metal hydrate which not only has a lower reactivity than the water-soluble metal salt used in coprecipitation but also has an adverse effect on the color and particle size of the final product, as well as an improvement in thermal stability It was hard to do. Therefore, in the present invention, such a problem can be solved by mixing the water-soluble metal salt and the basic compound in an appropriate ratio with respect to the total weight of the first metal hydroxide and the second metal hydroxide, and then gelling and reacting.

As a result, as described briefly above, in the present invention, a first metal hydroxide (M ^II (OH) ₂ ) which is a hydroxide of a metal having an oxidation number of +2, a second metal hydroxide which is a hydroxide of a metal having an oxidation number of +3 M ^ⅲ (OH) ₃₎ a was used as a raw material, and gelling a mixture of a water-soluble metal salt and a basic compound to the first metal hydroxide and the ranges of about 5-20% by weight relative to the total weight of the second metal hydroxides, pH 7 To a mixture of the metal hydroxide and an interlayer anion feed material in an aqueous solution adjusted to a neutral or weakly alkaline range in the range of from 1 to 9, and reacting at a high temperature / high pressure to produce a layered composite metal hydrate having improved thermal stability.

A first metal hydroxide (M ^Ⅱ (OH) ₂₎ is a hydroxide of a second, which may have an oxidation number of +2 metal, magnesium hydroxide (Mg (OH _2)), calcium hydroxide (Ca (OH ₂₎ according to the invention, (Zn (OH) ₂ , nickel hydroxide (Ni (OH) ₂ ), copper hydroxide (Cu (OH) ₂ ) or a mixture thereof and preferably magnesium hydroxide.

A second metal hydroxide according to the invention ^(Ⅲ M (OH) ₃₎ is a hydroxide of a third metal which may have an oxidation number of +3, aluminum hydroxide (Al (OH) _3), chromium hydroxide (Cr (OH) ₃ ), Iron hydroxide (Fe (OH) ₃ ), or a mixture thereof, preferably aluminum hydroxide. The first metal hydroxide and the second metal hydroxide are provided as a mixed metal component that forms the center of the layer of the layered composite metal hydrate finally produced.

Thus, in the present invention, since the hydroxyl group (OH ^- ) component constituting the intermetallic compound metal hydrate is contained in the first metal hydroxide and the second metal hydroxide as raw materials, the process of producing the hydrotalcite type layered composite metal hydrate It is not necessary to pass through a separate treatment process for supplying hydroxyl group to the reaction product.

The interlayer anion supply material according to the present invention is a material capable of supplying anions constituting both upper and lower surfaces between mixed metal components in hydrotalcite finally produced, and examples thereof include carbonate ions (CO ₃ ^2- ), nitrate ions NO ₃ ^- ), sulfate ion (SO ₄ ^2- ), phosphate ion (PO ₄ ^3- ), CrO ₄ ^2- , Cr ₂ O ₇ ^2- and the like. In the context of the present invention, the interlayer intervening anion supply material is preferably a material capable of supplying carbonate ions, more preferably sodium carbonate (Na ₂ CO ₃ ), carbonic acid (H ₂ CO ₃ ) and sodium bicarbonate (NaHCO ₃ ) At least one of them is selected, and most preferable is sodium bicarbonate.

Meanwhile, in the process of preparing a layered composite hydrate using the first metal hydroxide and the second metal hydroxide as a raw material, the pH of the aqueous solution may be adjusted to a pH of 7 to 9, which is a neutral or acidic alkaline level, The metal salt and the basic compound are mixed and gelled. That is, in the present invention, the raw material used for synthesizing the layered composite metal hydrate is characterized in that it is reacted in an aqueous solution maintained neutral or slightly alkaline. If the pH of the reaction system is less than 7, the layered composite metal hydrate is not industrially meaningful because it does not accumulate or occurs slowly. If the pH exceeds 9, the physical and chemical properties of the prepared layered complex hydrate, The thermal stability improvement effect of the polymer material was decreased.

The water-soluble metal salt which can be used in the present invention is a substance which can be dissociated in an aqueous solution and dissociated into metal cations and anions. Thus, the metal cation dissociated in the aqueous solution reacts with an anion formed by dissociation of a basic compound added to the reaction system together with a water-soluble metal salt, for example, a hydroxide ion to prevent the pH of the reaction system from being excessively changed to an alkaline level. On the other hand, the anion dissociated from the water-soluble metal salt binds to the cations generated by dissociation of the cation or intercalation anion supply material generated by dissociation of the basic compound, so that the pH of the reaction system is maintained at a neutral or weakly alkaline level.

The water-soluble metal salt which can be used according to a preferred embodiment of the present invention is a substance containing a metal component of group 2 or 3 of the periodic table, more preferably a metal contained in the first metal hydroxide or the second metal hydroxide , And most preferably a metal compound containing a metal component contained in the second metal hydroxide. The water-soluble metal salt which can be used in connection with the present invention may be selected from an aluminum salt, a magnesium salt or a mixture thereof, and is preferably selected from aluminum chloride, aluminum nitrate, aluminum sulfate or a mixture thereof.

Meanwhile, in the present invention, the basic compound used together with the water-soluble metal salt to control the pH of the aqueous solution may be any basic compound capable of dissociating in an aqueous solution to release hydroxide ions (OH ^- ). For example, a hydroxide of an alkali metal, and preferred examples thereof include sodium hydroxide, potassium hydroxide and the like.

As described above, in the course of mixing and dispersing the first metal hydroxide, the second metal hydroxide and the interlayer anion supplying material, which are raw materials of the layered composite hydrate of the present invention, in an aqueous solution, the pH of the reaction system is neutral or weakly alkaline And 5 to 20% by weight based on the total weight of the first metal hydroxide and the second metal hydroxide so as to maintain the pH in the range of 7 to 9. If the water-soluble metal salt and the basic compound are mixed in an amount of less than 5% by weight based on the metal hydroxide mixture, the pH of the reaction system is greatly increased to the alkali level and the effect of improving the physical and chemical properties such as the thermal stability of the resulting layer- And if it exceeds 20% by weight, the pH of the reaction system decreases to a weakly acidic level, making it difficult to synthesize the layered composite metal hydrate.

Particularly, in the state where the water-soluble metal salt and the basic compound are appropriately controlled and reacted and gelled, the first metal hydroxide, the second metal hydroxide and the intercalation anion supply material are mixed and dispersed at the same time to initiate a high- Alternatively, first, the first metal hydroxide and the second metal hydroxide may be added in the state where the acidic metal compound and the basic compound are mixed, and then the intercalation anion supply material may be added, but the last addition of the intercalation anion supply material desirable.

As described above, an aqueous solution containing a water-soluble metal salt-basic compound in a gelled state in an appropriate ratio to control the pH of the first metal hydroxide, the second metal hydroxide, the raw material component of the intercalation anion supply material, The reaction is initiated under conditions of high temperature and high pressure to obtain a layered composite metal compound in hydrotalcite form. The hydrotalcite-type layered composite metal hydrate synthesized according to the present invention can be represented by the following general formula.

[M ^II _1-x M ^III _x ] (OH) _n A ^{n -1} mH ₂ O (I)

In the general formula (I), M &lt; ^{II &gt;} and M &lt; ^{III &gt;} each represent a mixed metal component constituting the center of the layer in the hydrotalcite form, M ^II is a metal component, ^ⅲ M is a metal which may have an oxidation number of +3 component, that is a trivalent metal. (OH) is a component constituting both upper and lower surfaces between the mixed metal components, and A is an interlayer anion exchangeable with another anion.

According to a preferred embodiment of the present invention, the synthesis of the layered complex hydrate of the general formula (I) can be carried out at a temperature of 150 to 220 ° C, but in order to shorten the reaction time, And the pressure of the reaction system in the synthesis step may be selected in the range of 7 to 15 kgf / cm &lt; 2 &gt; depending on the reaction temperature. In this case, the temperature rise time to the reaction temperature is suitably within about 5 hours, and the reaction time takes about 20 to 180 minutes depending on the temperature of the reaction system.

When the aging step, that is, the synthesis step of the hydrotalcite-type layered composite metal hydrate, is terminated at such a high temperature and a high pressure, the cooling system is operated and a fatty acid-based material such as zinc stearate, calcium stearate (First metal hydroxide and second metal hydroxide), which can be selected from stearic acid, oleic acid, palmitic acid and the like, such as sodium stearate, in an amount of about 0.5 to 3.0% by weight, To carry out the surface treatment of the layered composite metal hydrate.

Once the surface treatment is completed, the product may be dehydrated, washed once, dried at a temperature of 150 ° C or lower, and pulverized to an appropriate size to produce a final product in the form of a fine powder.

Hereinafter, the present invention will be described in more detail with reference to exemplary embodiments.

Example 1

To mix the raw materials, 1.0 kg of water was added to the reactor, and 14.3 g of aluminum chloride (AlCl ₃ ) as a water-soluble metal salt and 4.3 g of sodium hydroxide (NaOH) as a basic compound were added to the reactor and stirred for about 20 minutes. Subsequently, 26.7 g of aluminum hydroxide (Al (OH) ₃ ) and 50.0 g of magnesium hydroxide (Mg (OH) ₂ ) were added and stirred more strongly for 20 minutes. After the raw material was sufficiently dispersed, 25.2 g of NaHCO ₃ as a CO ₃ feed material was added to the reactor, where the pH of the aqueous solution was maintained at 8.5-9.

Subsequently, the above reaction mixture was transferred to a hydrothermal reactor and aged for 20 to 180 minutes while maintaining a temperature of 170 to 200 DEG C and a pressure of 7 to 15 kgf / cm &lt; 2 &gt;. After the aging step was completed, the outer surface of the formed material was coated with fatty acid at a temperature in the range of 60 to 110 ° C. After completion of the coating step, the mixture was filtered once more, washed once with a small amount of water, filtered again, and dried at a temperature of 150 ° C or lower to prepare a final layered composite metal hydrate.

Example 2

In this Example, the procedure described in Example 1 was repeated except that 18.3 g of aluminum nitrate (Al (NO ₃ ) ₃ ) and 2.6 g of NaOH (basic compound) were fed into the reactor instead of AlCl ₃ as a water-soluble metal salt Layer composite metal hydrate was prepared.

Example 3

In this Example, the procedure described in Example 1 was repeated except that 17.1 g of AlCl ₃ as a water-soluble metal salt and 4.3 g of NaOH as a basic compound metal compound were added to maintain the pH of the aqueous solution inside the reactor at 7.5 to 8.0 Layer composite metal hydrate was prepared.

Comparative Example 1

In this Comparative Example, a layered composite metal hydrate according to the conventional hydrothermal synthesis method was prepared by mixing only the interlayer anion supplying material with the poorly soluble metal hydrate without using the water soluble metal salt and the basic compound.

First, 1.0 kg of water was put into the reactor, and then 33.4 g of Al (OH) ₃ which is a poorly soluble metal hydroxide and 50 g of Mg (OH) 2 were added and stirred vigorously for 20 minutes. Then 25.2 g of NaHCO ₃ as a CO ₃ feed material was dissolved in water as an interlayer anion and added to the above reactor to induce the reaction. Thereafter, the layered composite metal hydrate was prepared by aging, coating, filtering, washing and drying according to the same procedure as described in Example 1.

Comparative Example 2

In this Comparative Example, the procedure described in Example 1 was repeated except that 14.3 g of AlCl ₃ was added as a water-soluble metal salt and no basic compound was added to prepare a layered composite metal hydrate.

Experimental Example 1

In this Experimental Example, X-ray diffraction (XRD) analysis was performed to confirm the structure of the layered composite metal hydrate sample prepared in Example 1 above. The irradiation light used in this experiment was a Cu Ka1 ray, and the irradiation speed was 2? = 5? / Min. The measurement range was 2? = 5 to 80. The results of the X-ray diffraction analysis are shown in FIG.

As shown in FIG. 1, the diffraction of the (003), (006), and (009) planes is a typical feature of the layered structure material, and the material produced in this embodiment is a layered composite metal hydrate As shown in Fig.

Experimental Example 2

In this Experimental Example, differential scanning calorimetry (DSC) was performed to observe the pyrolysis characteristics of the layered composite metal hydrate sample prepared in Example 1 above. The differential thermal calorimeter was SHIMADZU DSC-60 and pyrolysis characteristics were observed up to 500 ℃ at a heating rate of 10 ℃ / min. The results of DSC analysis according to this experimental example are shown in FIG.

As shown in FIG. 2, the specimens prepared according to the embodiment of the present invention had absorption peaks at 256 ° C and 425 ° C. The temperature at which the water molecules were decomposed at 256 DEG C and the temperature at which the water molecules and carbon dioxide gas were decomposed at 425 DEG C were confirmed to be identical with the absorption peaks of hydrotalcite, which is a typical layered metal hydrate.

Experimental Example 3

In this Experimental Example, the particle type and surface characteristics of the layered composite metal hydrate sample prepared in the above example were photographed with a scanning electron microscope (SEM). The scanning microscope used SHIMADZU SS-550. 3 is a SEM photograph of a layered composite metal hydrate specimen manufactured according to the above embodiment.

As shown in FIG. 3, the layered composite metal hydrate prepared according to an embodiment of the present invention has a uniform particle distribution and has a fine particle shape.

Experimental Example 4

In this Experimental Example, the thermal stability effects of the layered composite metal hydrates prepared in Examples 1 to 3 and Comparative Examples 1 to 2 on the chlorine-containing resin (PVC resin) were compared and confirmed. The compositions of the formulations used for the thermal stability of the resins of Examples 1 to 3, Comparative Examples 1 to 2 and commercially available products are as follows. The unit in the composition is parts per hundred resin (PHR).

PVC resin (LG Chemical, LS-100) 100 parts by weight

DOP (di-octyl phthalate, LG Chemical) 25

TiO ₂ (DuPont, R-902) 3

Co-additive (? -Keto compound) 0.1

Stabilizer Zn-Stearate (Shinwon Chemical) ^* 0.75

Co-stabilizer Ca-Stearate (Shinwon Chemical) ^* 0.75

Layered composite metal hydrate sample 1.5

^* : Added 1.5 PHR for each control sample without added layered metal hydrate sample.

Of the formulations added above, DOP was a plasticizer and TiO2 was added to induce a white color on a clear PVC sheet. The auxiliary additives and auxiliary stabilizers were added to prevent the color from changing when working under the roll.

The compounding composition as described above was kneaded at 25 rpm for 3 minutes under a roll at 185 DEG C to prepare a specimen having a thickness of about 0.5 mm.

The prepared specimens were cut into a uniform size, and then placed in a silicon sheet. The specimens were taken out at an interval of 10 minutes until the initial 50 minutes, and then the specimens were taken out at intervals of 15 minutes. Respectively. The results of the presence or absence of discoloration are shown in FIG. 1, and the values of L (lightness, chromaticity) in the CIE L * a * b colorimetric system (CIELAB) obtained by measuring the observed specimen with a spectral colorimeter are shown in Table 1 below. In FIG. 1, the discoloration degree of the test piece according to the present invention and the comparative example, the product on the market and the control specimen are clearly distinguished (10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 65 minutes and 105 Min).

Table 1. Spectroscopic colorimetry Measured chromaticity (L)

    Example Time (minutes) Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Products 1 ^* Product 2 ^** Control specimen ^*** 0 95.35 94.91 94.92 94.80 94.63 94.52 95.44 96.06 10 94.82 94.63 94.69 94.72 94.48 93.92 95.23 95.79 20 94.62 94.65 94.63 94.68 94.27 93.32 94.90 89.82 30 94.36 94.20 94.13 93.51 93.76 92.54 95.01 38.87 40 93.78 93.76 93.01 88.02 92.67 91.48 94.08 50 92.42 82.60 92.20 52.43 90.15 90.96 93.18 65 91.24 91.16 90.69 52.86 89.35 91.99 105 81.21 78.22 55.23 72.98 58.98

^* : Using CLC-120 from Hubon Co., Ltd.

^** : Using Alcamizer 1 from Kyowa Chemical

^*** : Compound not containing layered composite metal hydrate

As shown in Table 1 and FIG. 1, the layered composite metal hydrate synthesized according to the preferred embodiment of the present invention maintained thermal stability even after 105 minutes, and discoloration hardly occurred, In the case of the layered composite metal hydrate, the thermal stability of the PVC resin was greatly reduced after 50 to 65 minutes, and discoloration to black occurred. That is, in the case of the sample in which the water-soluble metal salt and the basic compound were not added in the course of synthesizing the layered composite metal hydrate, discoloration was observed in black after 50 minutes (Comparative Example 1) At 65 minutes, a discoloration was observed in black (Comparative Example 2).

On the other hand, in the case of a commercial product, the thermal stability of the PVC resin was lowered and the degree of discoloration of the PVC resin was deteriorated with time as compared with the product synthesized in the examples of the present invention. Particularly, in the case of the control specimen in which the layered composite metal hydrate was not added at all, it was found that the thermal stability of the PVC resin decreased from the point of time when 30 minutes passed.

The above-described embodiments are illustrative examples of the present invention in order to explain the present invention in detail, but the present invention is not limited thereto. Rather, many modifications and variations will readily occur to those skilled in the art to which the invention pertains. It will be apparent, however, that such modifications and variations are within the scope of the present invention as far as they do not depart from the spirit of the invention.

As described above, the layered composite metal hydrate prepared according to the present invention has a more complete crystal structure, pyrolysis characteristics, and a plate-like structure than those obtained by mixing only a mixture of metal hydroxides as a starting material and an interlayer anion supply material .

Particularly, it has been confirmed that the layered composite metal hydrate prepared according to the present invention can greatly improve the thermal stability effect for a halogen-containing resin such as PVC. That is, by giving a greatly improved thermal stability effect to the halogenated resin, the halogenated resin can be prevented from being discolored by heat.

In addition, unreacted materials remaining in the layered composite metal hydrate prepared only from the metal hydroxide and the interlayer anion supply material are removed using a water-soluble metal salt-basic compound mixture, and the pH range in the synthesis step is maintained neutral or weakly alkaline The quantity can be greatly reduced.

On the other hand, the water-soluble metal salt-basic compound mixture used in the reaction step was advantageous both industrially and economically since the reaction time was greatly reduced by improving the reaction activity.

1 is a graph showing the results of X-ray diffraction analysis of a layered composite metal hydrate prepared according to a preferred embodiment of the present invention;

FIG. 2 is a graph showing the results of differential scanning calorimetry of a layered composite metal hydrate prepared according to a preferred embodiment of the present invention; FIG.

FIG. 3 is a photograph of the layered composite metal hydrate prepared according to the preferred embodiment of the present invention, taken by an electron microscope;

FIG. 4 is a graph showing the relationship between the chromaticity and the chromaticity of the PVC resin after mixing and applying the examples of the present invention, the comparative example and the conventionally prepared layered composite metal hydrate and the compound without addition of the layered composite metal hydrate, Of FIG.

Claims (6)

(a) a first metal hydroxide _{^{(M Ⅱ (OH) 2)}} , a second metal hydroxide (M ^Ⅲ (OH) ₃₎ and the aqueous solution control the interlayer negative ion supplying substance to pH 7 ~ 9 range by the water-soluble metal salt and a basic compound Mixing and dispersing the mixture; (b) reacting the aqueous solution containing the first metal hydroxide, the second metal hydroxide and the interlayer anion feed material at a high pressure in a temperature range of 170 to 220 ° C. The method according to claim 1, Further comprising the step of surface-treating the layered composite metal hydrate at a temperature of 60 to 110 ° C after the step (b). The method according to claim 1, Wherein the water-soluble metal salt and the basic compound are added in an amount of 5 to 20% by weight based on the total amount of the first metal hydroxide and the second metal hydroxide in the step (a). The method according to claim 1, Wherein the water-soluble metal salt is an aluminum salt, and the basic compound is a hydroxide of an alkaline-earth metal. The method according to any one of claims 1 to 4, Wherein the water-soluble metal salt is selected from at least one of aluminum chloride, aluminum nitrate and aluminum sulfate. The method according to claim 1, Wherein the interlayer anion supplying material is at least one selected from the group consisting of carbonic acid, sodium carbonate and sodium bicarbonate.