KR102379372B1 - A composition for fumed silica - Google Patents

Abstract

The present invention relates to a composition for fumed silica, comprising a first silicon precursor containing an alkyl group, a second silicon precursor containing a halogen group, and a third silicon precursor containing a hydrocarbon compound and a silane compound.

Description

Composition for fumed silica

The present invention relates to a composition for fumed silica that can economically produce fumed silica.

Silica can be divided into anhydrous silica and hydrated silica according to the synthesis method. Silica produced by the pyrolysis process is anhydrous silica because it is produced in the absence of water at high temperature, and the wet process in aqueous solution Silica produced by the is hydrated silica. In addition, among the commercially widely used types, fumed silica and electric arc silica correspond to anhydrous silica, and precipitated silica corresponds to hydrated silica. In particular, the fumed silica is used as a functional material in various fields such as buildings, automobiles, and semiconductors.

Specifically, Japanese Patent Registration No. 4723252 (Patent Document 1) discloses a method for producing fumed metal oxide particles using a liquid feedstock containing a volatile non-halogenated metal oxide precursor, which is a silicon-containing compound. However, the manufacturing method of Patent Document 1 stoichiometrically has a problem in that the silica production rate from silane is low, and expensive raw materials must be used.

Meanwhile, in various fields, industrial by-products or industrial wastes such as slag from steel mills and ash from thermal power plants are generated. Conventional industrial by-products have been mainly treated by landfill, but there is a problem in that harmful substances are leaked along with leachate from the landfill, causing problems such as soil pollution, water pollution, and marine pollution.

Therefore, there is a need for research and development on a composition for fumed silica capable of economically and efficiently manufacturing fumed silica due to reduction in the cost of disposal and reduction in raw material cost of industrial by-products, including industrial by-products.

Japanese Patent Registration No. 4723252 (published on March 3, 2006)

The present invention provides a composition for fumed silica capable of economically and efficiently manufacturing fumed silica due to reduction in the cost of disposal and reduction in raw material cost of industrial by-products, including industrial by-products.

In order to achieve the above object, the present invention provides a composition for fumed silica, comprising a first silicon precursor containing an alkyl group, a second silicon precursor containing a halogen group, and a third silicon precursor containing a hydrocarbon compound and a silane compound.

In addition, the present invention provides a fumed silica prepared from the composition for fumed silica.

The composition for fumed silica according to the present invention can reduce the cost of disposal and raw material cost of industrial by-products, including industrial by-products, so that the fumed silica can be produced economically and efficiently.

Hereinafter, the present invention will be described in detail.

Composition for Fumed Silica

The composition for fumed silica according to the present invention includes an alkyl group-containing first silicon precursor, a halogen group-containing second silicon precursor, and a third silicon precursor. The precursors serve to flame hydrolyze to form fumed silica.

first silicon precursor

The first silicon precursor may include an alkyl group and, for example, may be represented by Chemical Formula 1 below.

[Formula 1]

R ¹ _a SiR ² _4-a

In Formula 1,

R ¹ is an alkyl group having 1 to 5 carbon atoms,

R ² is a halogen group,

a is an integer from 1 to 4.

Specifically, R ¹ may be an alkyl group having 1 to 3 carbon atoms, or a methyl group, ethyl group, n-butyl group or isobutyl group, R ² may be a fluorine group, a chlorine group, a bromine group or a zinc group, and a is 1 to It may be an integer of 3, or 1 or 2.

Specifically, the first silicon precursor may be at least one selected from the group consisting of methyltrichlorosilane, dimethyldichlorosilane, ethyltrichlorosilane, diethyldichlorosilane, methyldichlorosilane and ethyldichlorosilane.

In addition, the first silicon precursor may have a metal content of 10 ppm or less, or 1 ppm or less. When the metal content of the first silicon precursor is within the above range, there is an effect that the appearance characteristics of the generated fumed silica are improved.

The first silicon precursor may be included in the composition in an amount of 50 to 80 parts by weight, or 60 to 70 parts by weight based on 20 to 40 parts by weight of the second silicon precursor. When the content of the first silicon precursor is within the above range, it is advantageous for economical production of fumed silica.

second silicon precursor

The second silicon precursor may include a halogen group and, for example, may be represented by Chemical Formula 2 below.

[Formula 2]

R ³ _b SiH _4-b

In Formula 2,

R ³ is a halogen group,

b is an integer of 1 to 4.

Specifically, R ³ may be a fluorine group, a chlorine group, a bromine group, or a zinc group, and b may be an integer of 1 to 4.

Specifically, the second silicon precursor may be at least one selected from the group consisting of tetrachlorosilane, trichlorosilane, dichlorosilane and monochlorosilane.

In addition, the second silicon precursor may have a metal content of 10 ppm or less, or 1 ppm or less. When the metal content of the second silicon precursor is within the above range, there is an effect that the appearance characteristics of the generated fumed silica are improved.

The second silicon precursor may be included in the composition in an amount of 20 to 40 parts by weight, or 25 to 35 parts by weight based on 50 to 80 parts by weight of the first silicon precursor. When the content of the second silicon precursor is within the above range, it is advantageous for economical production of fumed silica.

tertiary silicon precursor

The third silicon precursor includes a hydrocarbon compound and a silane compound. For example, the third silicon precursor may include 1 to 25 parts by weight or 1 to 20 parts by weight of the hydrocarbon compound, and 75 to 99 parts by weight or 80 to 99 parts by weight of the silane compound. Specifically, the third silicon precursor may be a by-product of an organic halide synthesis process, for example, a by-product of a methylchlorosilane synthesis process by a direct synthesis method.

When the content of the hydrocarbon compound and the silane compound included in the third silicon precursor is within the above range, fumed silica having a target BET specific surface area, pH, and chlorine content can be prepared, and excellent plasticity when applied to silicone rubber , storage properties and tensile strength can be imparted.

At this time, the hydrocarbon compound is 2-methylbutane (2-methylbutane), 2,2,3-trimethylbutane (2,2,3-trimethylbutane), butane (Butane), 2-methylpentane (2-methylpentane), 2 ,3-dimethylpentane (2,3-demethylpentane), 2,2,3-trimethylpentane (2,2,3-trimethylpentane), 2,3,4-trimethylpentane (2,3,4-trimethylpentane), 2 , 2,4-trimethylpentane (2,2,4-trimethylpentane), including one or more selected from the group consisting of pentane (pentane) and hexane (hexane), for example, includes 2-methylbutane or pentane can do.

The silane compound is dimethylsilane, trimethylsilane, tetramethylsilane, dichlorosilane, trichlorosilane, silicon tetrachloride, dimethylchlorosilane. , Methyldichlorosilane (methyldichlorosilane), trimethylchlorosilane (trimethylchlorosilane), dimethyldichlorosilane (dimethyldichlorosilane), methyltrichlorosilane (methyltrichlorosilane) and trimethyltrichlorodisilane (trimethyltrichlorodisilane) containing one or more selected from the group consisting of, For example, it may include at least one selected from the group consisting of tetramethylsilane, trichlorosilane, dimethylchlorosilane, and methyldichlorosilane.

In addition, the third silicon precursor may be included in the composition in an amount of 1 to 10 parts by weight, or 2 to 7 parts by weight based on 50 to 80 parts by weight of the first silicon precursor. When the content of the third silicon precursor is within the above range, it is advantageous for economical production of fumed silica.

The composition for fumed silica as described above can reduce the disposal cost and raw material cost of industrial by-products, including the third silicon precursor, which is an industrial by-product as a precursor, so that fumed silica can be manufactured economically and efficiently.

Fumed Silica

In the present invention, the fumed silica is prepared from the composition for fumed silica as described above.

The fumed silica has a BET specific surface area of 130 to 230 m ² /g, a pH of 3.9 to 4.5, and a chlorine content of 50 ppm or less. Specifically, the fumed silica may have a BET specific surface area of 140 to 220 m ² /g, a pH of 3.9 to 4.3, and a chlorine content of 20 ppm or less.

When the BET specific surface area of the fumed silica is less than 130 m ² /g, it may cause discoloration of the manufactured product ^. can lower it

In addition, when the pH of the fumed silica is less than 3.9 or exceeds 4.5, the surface treatment efficiency in manufacturing the silicone rubber may be reduced, thereby reducing the storage properties of the silicone rubber.

When the chlorine content of the fumed silica exceeds 50 ppm, the surface treatment efficiency may be reduced during manufacturing of the silicone rubber, thereby reducing the storage properties of the silicone rubber.

In addition, the fumed silica as described above may have hydrophilicity.

Hereinafter, the present invention will be described in more detail through examples. However, these examples are only for helping the understanding of the present invention, and the scope of the present invention is not limited to these examples in any sense.

[Example]

Examples 1 to 6 and Comparative Examples 1 to 4. Preparation of fumed silica

Fumed silica was prepared by mixing the components with the same content as in Table 1.

Specifically, in the reactor, methyltrichlorosilane (precursor A, first silicon precursor), tetrachlorosilane (precursor B, second silicon precursor) and precursor C (third silicon precursor) of methylchlorosilane (MCS) production process Fumed silica was prepared by supplying a by-product as a liquid feedstock, and injecting a mixed gas in which air and hydrogen were mixed in a volume ratio of 25:1 as combustion gas.

At this time, Examples 1, 3 and 4 are precursor C of 7.3 wt% 2-methylbutane, 7.7 wt% pentane, 1.3 wt% tetramethylsilane, 1.0 wt% trichlorosilane, 0.2 wt% dimethylchloro A precursor composed of silane and 82.5% by weight of methyldichlorosilane was used.

In addition, Example 2 is precursor C of 1.8% by weight 2-methylbutane, 1.2% by weight pentane, 3.2% by weight tetramethylsilane, 1.1% by weight trichlorosilane, 0.3% by weight dimethylchlorosilane and 92.4% by weight. A precursor composed of % of methyldichlorosilane was used.

Example 5 is Precursor C of 9.8 wt% 2-methylbutane, 9.2 wt% pentane, 3.1 wt% tetramethylsilane, 1.2 wt% trichlorosilane, 0.3 wt% dimethylchlorosilane and 76.4 wt% A precursor composed of methyldichlorosilane was used, and in Example 6, 11.2 wt% of 2-methylbutane, 10.8 wt% of pentane, 2.4 wt% of tetramethylsilane, 1.3 wt% of trichlorosilane, and 0.3 wt% of Precursor C were used. % of dimethylchlorosilane and 74% by weight of methyldichlorosilane was used as a precursor.

In Comparative Example 2, a precursor composed of 5.3 wt% of tetramethylsilane, 2.1 wt% of trichlorosilane, 0.3 wt% of dimethylchlorosilane and 92.3 wt% of methyldichlorosilane was used as the precursor C.

Comparative Example 3 is precursor C of 0.5 wt% 2-methylbutane, 0.3 wt% pentane, 4.2 wt% tetramethylsilane, 2 wt% trichlorosilane, 0.3 wt% dimethylchlorosilane and 92.7 wt% A precursor composed of methyldichlorosilane was used, and in Comparative Example 4, 14.1 wt% of 2-methylbutane, 12.9 wt% of pentane, 3 wt% of tetramethylsilane, 1.2 wt% of trichlorosilane, and 0.2 wt% of Precursor C were used. % of dimethylchlorosilane and 68.6% by weight of methyldichlorosilane was used.

division Supply (kg/hr) Content of hydrocarbons in precursor C (wt%) precursor hydrogen A B C Example 1 660 300 30 8 15 Example 2 660 300 30 8 3 Example 3 750 210 30 7.8 15 Example 4 570 390 30 8.2 15 Example 5 660 300 30 8 19 Example 6 660 300 30 8 22 Comparative Example 1 700 300 - 8.5 - Comparative Example 2 660 300 30 8 - Comparative Example 3 660 300 30 8 0.8 Comparative Example 4 660 300 30 8 27

experimental example. Characterization of Fumed Silica

The properties of the fumed silica prepared in Examples and Comparative Examples were measured in the following manner, and the results are shown in Table 2 below.

(1) specific surface area

The specific surface area of the fumed silica was measured by pre-treating 0.05 g of fumed silica at 300° C. for 30 minutes, and then using a Macsorb-1208 manufactured by Mountech as a BET specific surface area measuring device.

(2) chlorine content

The chlorine content of fumed silica was measured using ion chromatography (IC) DIONEX ICS-1000. At this time, as a sample, 1 g of fumed silica was added to 100 g of ultrapure purified water (DI water) and a dispersion solution dispersed using an ultrasonic disperser (dispersion conditions: 60 Hz, 2 min) was used. In addition, as an eluent, a mixed solution consisting of 0.371 g of sodium carbonate, 0.084 g of sodium bicarbonate, and 1 L of ultrapure purified water was used.

division Specific surface area (m ² /g) pH Chlorine content (ppm) Example 1 202.7 4.18 10.5 Example 2 153.1 4.17 11.2 Example 3 217.6 4.18 18.7 Example 4 167.3 4.19 8.9 Example 5 208.4 4.18 10.7 Example 6 226.4 4.19 10.9 Comparative Example 1 240.4 4.19 11.8 Comparative Example 2 124.1 4.18 11.7 Comparative Example 3 125.5 4.19 9.3 Comparative Example 4 244.7 4.19 11.5

As shown in Table 2, the fumed silica of Examples in which the content of the hydrocarbon compound in the precursor C satisfies the range of the present invention has a BET specific surface area of 150 to 230 m ² /g, a pH of 4.0 to 4.2, and a chlorine content 20 ppm or less was satisfied, but in the case of the comparative example, it was found that the desired specific surface area could not be formed.

Claims (6)

A first silicon precursor containing an alkyl group;
a second silicon precursor containing a halogen group; and
A third silicon precursor containing 1 to 25 parts by weight of a hydrocarbon compound and 75 to 99 parts by weight of a silane compound
including,
The hydrocarbon compound is 2-methylbutane (2-methylbutane), 2,2,3-trimethylbutane (2,2,3-trimethylbutane), 2-methylpentane (2-methylpentane), 2,3-dimethylpentane (2 ,3-demethylpentane), 2,2,3-trimethylpentane (2,2,3-trimethylpentane), 2,3,4-trimethylpentane (2,3,4-trimethylpentane), 2,2,4-trimethylpentane (2,2,4-trimethylpentane), pentane (pentane) and hexane (hexane) comprising at least one selected from the group consisting of, a composition for fumed silica. delete The method according to claim 1,
The composition comprises 50 to 80 parts by weight of the first silicon precursor, 20 to 40 parts by weight of the second silicon precursor, and 1 to 10 parts by weight of the third silicon precursor, the composition for fumed silica. The method according to claim 1,
The silane compound is dimethylsilane, trimethylsilane, tetramethylsilane, dichlorosilane, trichlorosilane, silicon tetrachloride, dimethylchlorosilane. , methyldichlorosilane (methyldichlorosilane), trimethylchlorosilane (trimethylchlorosilane), dimethyldichlorosilane (dimethyldichlorosilane), methyltrichlorosilane (methyltrichlorosilane) and trimethyltrichlorodisilane (trimethyltrichlorodisilane) containing at least one selected from the group consisting of fumed, A composition for silica. Fumed silica prepared from the composition for fumed silica of any one of claims 1, 3, and 4. 6. The method of claim 5,
The fumed silica has a BET specific surface area of 130 to 230 m ² /g, a pH of 3.9 to 4.5, and a chlorine content of 50 ppm or less.