JP2003267722A - Nonporous spherical silica and method of manufacturing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonporous spherical silica having a certain particle size distribution, where the maximum particle diameter can be optionally set to a value within a certain range and a nonporous spherical silica having a particle diameter over the said value is not substantially included, and a method of manufacturing the same. <P>SOLUTION: A spherical silica gel formed by a reaction of a hydrolyzable silicon compound with water is separated, dried, sieved by a sieve with ≥250 meshes, and finally fired to give a nonporous spherical silica. In the presence of an organic solvent incompatible with water, a surfactant, and a catalyst, a water-in-oil type emulsion is formed and a hydrolyzable silicon compound and water are reacted to form the silica gel. The resulting silica gel is separated, dried, sieved by a sieve with ≥250 meshes, and finally fired to give a nonporous spherical silica. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a non-porous spherical silica and a method for producing the same, and its object is to set the maximum particle diameter to any value within a certain range,
It is an object of the present invention to provide a non-porous spherical silica which does not contain non-porous spherical silica having a particle size substantially exceeding the value and has a certain degree of particle size distribution, and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Spherical silica is used for various purposes such as a filler for resin molding, a sealant for electronic materials, a spacer and a gap agent. Spherical silica is manufactured by the following method. For example, a silicon compound tetraalkoxysilane is hydrolyzed in water or a water / alcohol mixed solution to form a silica sol. The obtained silica sol is added to an oily dispersion medium composed of an aromatic hydrocarbon such as benzene, toluene, xylene, and ethylbenzene and an emulsifier such as a long-chain organic carboxylic acid or a surfactant, and emulsified. It is produced by a method in which a silica sol is gelled, the obtained silica gel is dehydrated, and baked at 900 to 1200 ° C. (see JP-A-1-145318).

In addition, a spherical silica dispersion obtained by hydrolyzing tetraalkoxysilane in methanol contains a trimethylsilylating agent (chlorotrimethylsilane, trimethylsilanol, Methoxytrimethylsilane, hexamethyldisilazane) to trimethylsilylate silanol groups on the surface of spherical silica, remove excess trimethylsilylating agent, and then dry the dispersion (see JP-A-3-187913). Being manufactured.

[0004]

In recent years, when spherical silica is used as a spacer or a filler, it has been required to make the maximum particle diameter of particles equal to or less than a certain value. If the particle size is large to some extent, the target spherical silica can be obtained by removing the spherical silica having a particle size exceeding the particle size by sieving. However, the required maximum particle size of spherical silica has decreased, and is currently 40μ.
m or less is required. In the case of such a small particle diameter, for example, when sieving the spherical silica produced by the above-described production method, clogging of the sieve occurs due to static electricity on the surface of the spherical silica, and sieving is difficult. . In addition, even with an airflow classifier, it was not possible to strictly match the maximum particle size with such a small particle size. Further, in the case of monodisperse spherical silica having a narrow particle size distribution width, it has a close packing structure and loses fluidity. High fluidity can be obtained by having a certain size distribution width. As for spherical silica having a certain particle size width, if the maximum particle diameter obtained as described above is large to some extent, the desired spherical silica can be obtained by sieving. However, in the case of spherical silica having a small particle size, it is difficult to even sieve the particles, and the intended spherical silica cannot be obtained.

[0005]

The present invention has been made to solve the above problems, and the invention according to claim 1 is produced by reacting a hydrolyzable silicon compound with water. The separated spherical silica gel is separated and dried, then 250
The present invention relates to a non-porous spherical silica characterized by being subjected to a sieving treatment using a sieve having a mesh size or more and finally calcined. The invention according to claim 2 has a number average particle diameter of 40 μm.
The non-porous spherical silica according to claim 1, characterized in that it is substantially free of non-porous spherical silica having a particle diameter of less than or equal to 45 μm or less and a value arbitrarily selected from the range of 45 μm or less. Regarding The invention according to claim 3 has a number average particle diameter of 40 µm or less, satisfies the following relational expressions (equation 3) and relational expression (equation 4), and has a value arbitrarily selected from the range of 5 to 45 µm. The non-porous spherical silica according to claim 1, which is substantially free of non-porous spherical silica having a particle size exceeding the above range.

[Formula 3] (However, in the formula, S is a specific surface area (m ²
/ G) and d are number average particle diameters (μm). )

[Formula 4] (However, D ₉₀ in the formula is a cumulative 90% by volume particle diameter, D ₁₀
Is a cumulative particle size of 10% by volume. The invention according to claim 4 is to react a hydrolyzable silicon compound with water while forming a water-in-oil emulsion in the presence of an organic solvent incompatible with water, a surfactant and a catalyst. The present invention relates to a method for producing non-porous spherical silica, which comprises producing silica gel, separating and drying the produced silica gel, performing a sieving treatment using a sieve having a mesh of 250 or more, and finally calcining.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The non-porous spherical silica and the method for producing the same according to the present invention will be described below. The non-porous spherical silica according to the present invention is a spherical silica gel produced by reacting a hydrolyzable silicon compound with water, separated, dried, and then sieved using a sieve of 250 mesh or more, and finally. It can be obtained by firing. And the number average particle diameter is 40 μm or less, and the maximum particle diameter is within the range of 45 μm or less, and the non-porous spherical particles having the particle diameter exceeding the value (maximum particle diameter) arbitrarily set from the above range. Silica is substantially free. Further, the non-porous spherical silica according to the present invention is a non-porous spherical silica in which the spherical silica particles are substantially monodispersed without agglomerating, satisfying the following relational expressions (equation 5) and relational expression (equation 6) It is preferably silica.

[Formula 5] (However, in the formula, S is a specific surface area (m ²
/ G) and d are number average particle diameters (μm). )

[Formula 6] (However, D ₉₀ in the formula is a cumulative 90% by volume particle diameter, D ₁₀
Is a cumulative particle size of 10% by volume. )

The non-porous spherical silica according to the present invention has a particle size of 45 μm.
Within the range of m or less, the maximum particle diameter can be set arbitrarily. Spherical silica having a particle size exceeding this value is not substantially contained, and since the particle size distribution width is wide, it has excellent fluidity and can be suitably used as a filler or a spacer.

Next, the method for producing non-porous spherical silica according to the present invention will be described. In order to obtain the non-porous spherical silica according to the present invention, first, a W / O type emulsion is formed in the presence of a surfactant, water and a catalyst in an organic solvent incompatible with water, A hydrolyzable silicon compound is hydrolyzed and polycondensed to prepare a slurry containing spherical silica.

The hydrolyzable silicon compound used (hereinafter, simply referred to as a silicon compound) is not particularly limited, but an alkoxysilane compound or a derivative thereof can be exemplified. Specific examples include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, and the like. Further, examples of derivatives of these compounds include low condensation products obtained by partially hydrolyzing the above silicon compounds. Furthermore, two or more kinds of the silicon compounds described above can be mixed and used.

As the organic solvent which is incompatible with water, aliphatic hydrocarbons such as hexane, heptane, octane, nonane, decane, undecane and dodecane, alicyclic hydrocarbons such as cyclohexane, methylcyclohexane and decalin, Aromatic hydrocarbons such as benzene, toluene, xylene, dodecylbenzene, methylnaphthalene, ethers such as dibutyl ether, dipentyl ether, dihexyl ether, diheptyl ether, dioctyl ether, petroleum distillate classification such as naphtha, white kerosene, etc. It can be illustrated. Particularly in the present invention, it is preferable to use n-heptane, toluene and xylene. The amount of the organic solvent that is incompatible with water used is not particularly limited,
It is 0.5 to 10 volumes, preferably 1 to 5 volumes, per volume of the silicon compound used.

As the surfactant, it is preferable to use a nonionic surfactant, such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, sorbitan fatty acid esters, polyoxyethylene sorbitan aliphatic esters, and fatty acids. Examples thereof include monoglycerides, polyethylene glycol fatty acid esters, polyoxyethylene alkylamines, and polyglycerin fatty acid esters. Particularly in the present invention, it is preferable to use a nonionic surfactant having an HLB of 12 or less, and examples of such a nonionic surfactant include sorbitan monooleate, polyoxyethylene nonylphenyl ether, and tetraglycerin monostearate. You can The amount of the surfactant used is not particularly limited, but the silicon compound 1 used
Per volume, 0.001 to 0.4 volume, preferably 0.1.
The capacity is 002 to 0.2.

As the catalyst, an acid catalyst such as hydrochloric acid, nitric acid, sulfuric acid, boric acid, phosphoric acid, formic acid, acetic acid or oxalic acid, or an alkali catalyst such as ammonia, urea, ethanolamine or tetramethylammonium hydroxide should be added. You can Particularly in the present invention, it is preferable to use an acid catalyst such as formic acid or acetic acid.

The amount of water is not particularly limited, but is 1 to 20 mol, preferably 2 per mol of the silicon compound used.
It is set to 10 mol. The amount of water used affects the particle size of the spherical silica formed. If the amount of water is relatively increased, the particle size of the spherical silica can be reduced, and if the amount of water is relatively decreased, the particle size of the spherical silica can be increased. Therefore, the particle size of the spherical silica can be arbitrarily adjusted by the ratio of water and the organic solvent.

In order to form a W / O type emulsion in the presence of a surfactant, water and a catalyst in an organic solvent which is incompatible with water, an organic solvent which is incompatible with water, a surfactant and water are used. The catalyst may be mixed and heated with stirring. here,
By adding a silicon compound, hydrolysis and polycondensation can be performed in the emulsion to prepare a slurry containing spherical silica. Thus, by stirring the silicon compound in an organic solvent containing water to cause hydrolysis and condensation, spherical silica having a uniform particle size can be obtained. The reaction temperature is generally 0 to 100 ° C., preferably 30 to 80 ° C., and the reaction time is 30 minutes to 30 hours, preferably 1 to 10 hours.

Next, silica gel is separated by decanting or filtering the slurry containing the spherical silica prepared by the above method. The separated silica gel is dried. The drying treatment is usually carried out by treating under a temperature condition of 30 to 300 ° C. for 1 to 30 hours. A preferable drying treatment is 1 to 1 under a temperature condition of 50 to 200 ° C.
It takes about 30 hours.

Next, the dried silica gel is subjected to a sieving treatment. The sieve used has a size of 250 mesh or more (opening of 60 μm or less). This makes it possible to remove silica gel having a particle size exceeding the required maximum particle size. In the present invention, silica gel having an arbitrary maximum particle diameter can be obtained, but in the usual case, the maximum particle diameter is 45 μm or less. By performing the sieving treatment before firing the silica gel, the sieving can be performed with a good recovery rate without causing clogging of the sieve.

Finally, the non-porous spherical silica according to the present invention can be produced by calcining the silica gel whose maximum particle size is adjusted to be not more than an arbitrary value. The firing temperature is 500 to 1300 ° C. The reason for this is 5
When the temperature is lower than 00 ° C, non-porous spherical silica cannot be obtained because numerous pores are formed on the surface of the spherical silica, and when higher than 1300 ° C, the spherical silicas are condensed with each other to form an aggregate. This is because the non-porous spherical silica monodispersed cannot be obtained, which is not preferable in any case. The firing time is not particularly limited, but it is 1 to 3.
It is set to 0 hours. The reason for this is that if the calcination treatment is performed for less than 1 hour, organic substances remain and pores are formed on the surface of the spherical silica, and if calcination is performed for more than 30 hours, aggregates that are difficult to disintegrate are formed. This is because in any case, it is not preferable because of the presence of

[0018]

EXAMPLES The present invention will be described below based on examples.
The invention is in no way limited to these examples. The blending amount is% by weight. <Preparation of Sample of Example 1> In a 1 L reactor equipped with a stirrer, 500.1 g of alkylbenzene and 126.2 of pure water were added.
g, decaglyceryl trioleate (HLB 7.0)
1.3 g and 1.1 g of acetic acid were added and vigorously stirred for 10 minutes to emulsify. In this emulsion, tetramethoxysilane 2
00.0 g was added and hydrolyzed by stirring at 45 ° C. for 2 hours. Then, the internal temperature was raised to 140 ° C. and low-boiling components were distilled off to obtain a silica gel slurry. This was filtered to separate silica gel, and the silica gel was washed with methanol. The silica gel thus obtained is dried at 60 ° C. for 4 hours, and the open pores are 24 μm.
The sieving process is carried out using a sieve of m.
By firing at 0 ° C. for 2 hours, the spherical silica of Example 1 was obtained.

<Preparation of Sample of Example 2> In a 1 L reaction vessel equipped with a stirrer, 631.0 g of alkylbenzene and 1 part of pure water were added.
55.0 g, decaglyceryl trioleate (HLB
7.0) 3.2 g and acetic acid 1.4 g were added, and the mixture was vigorously stirred for 10 minutes to emulsify. To this emulsion, 160.0 g of tetramethoxysilane was added and stirred at 45 ° C. for 2 hours for hydrolysis. Then, the internal temperature was raised to 140 ° C. and low-boiling components were distilled off to obtain a silica gel slurry. This was filtered to separate silica gel, and the silica gel was washed with methanol. The obtained silica gel was dried at 60 ° C. for 4 hours, subjected to sieving treatment using a sieve having openings of 11 μm, and calcined at 1000 ° C. for 2 hours to give Example 2.
Spherical silica was obtained.

<Preparation of Sample of Comparative Example 1> In the preparation of the sample of Example 1, drying was carried out at 60 ° C. for 4 hours and then calcination was carried out at 1050 ° C. for 2 hours without sieving treatment. The spherical silica of Example 1 was obtained.

<Preparation of Sample of Comparative Example 2> In the preparation of the sample of Example 1, after drying at 60 ° C. for 4 hours, sieving treatment was not first performed and then calcination was performed at 1050 ° C. for 2 hours, followed by opening. A sample of Comparative Example 2 was obtained by performing a sieving process using a 20 μm sieve.

<Preparation of Sample of Comparative Example 3> In the preparation of the sample of Example 2, after drying at 60 ° C. for 4 hours, sieving treatment was not first performed and then firing was performed at 1000 ° C. for 2 hours, followed by opening. A sample of Comparative Example 3 was obtained by performing a sieving process using a 11 μm sieve.

<Test Example 1; Measurement of Physical Properties> The particle size distribution and number average particle size (μm) (d) of the obtained spherical silicas of Examples 1 and 2 and Comparative Examples 1 to 3 were measured with a laser manufactured by Cirrus. It measured using the particle size distribution analyzer (CILAS 1180 Liquid). “Standard deviation σ = (D ₉₀ / D ₁₀ ) ^0.5 ” was calculated from the data of the particle size distribution. Further, the specific surface area (m ² / g) (S) was measured by the BET method, and S × d was calculated from the data of the number average particle diameter (d) by the above laser particle size distribution meter. Further, the maximum particle size was measured by electron microscopy. That is, electron microscope magnification 500-
500 or more spherical silica particles were randomly observed at 1000 times, and the maximum particle size in the observed image was measured by the scale attached to the apparatus to be the maximum particle size. In addition, regarding the sample subjected to the sieving treatment at the time of production, the presence or absence of clogging of the sieve was observed, and the recovery rate of the sample after the sieving treatment was calculated.

[0024]

[Table 1]

[0025]

As described above in detail, the non-porous spherical silica according to the present invention can have a maximum particle size arbitrarily set within the range of 45 μm or less, and the non-porous spherical silica exceeding the maximum particle size. Since it is not contained, it can be suitably used as a filler or a spacer. Further, the method for producing non-porous spherical silica according to the present invention can produce non-porous spherical silica having a maximum particle size arbitrarily set within the range of 45 μm or less. Moreover, since no clogging occurs during sieving, spherical silica can be produced with good recovery.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Haruo Masa             Fuso, 9-19 Tomizawa-cho, Nihonbashi, Chuo-ku, Tokyo             Chemical Industry Co., Ltd. Tokyo Branch F term (reference) 4G072 AA25 BB07 GG01 GG03 HH19                       HH30 MM01 MM28 MM36 RR12                       RR13 TT01 TT06 UU09

Claims (4)

[Claims] 1. A spherical silica gel produced by reacting a hydrolyzable silicon compound with water is separated and dried, and then 2
A non-porous spherical silica characterized by being sieved using a sieve of 50 mesh or more and finally calcined. 2. A non-porous spherical silica having a number average particle size of 40 μm or less and a particle size exceeding a value arbitrarily selected from the range of 45 μm or less is substantially not included. The non-porous spherical silica according to claim 1. 3. A number average particle diameter of 40 μm or less, satisfying the following relational expressions (Equation 1) and relational expression (Equation 2), and having a particle diameter exceeding a value arbitrarily selected from the range of 45 μm or less. The non-porous spherical silica according to claim 1, which is substantially free of non-porous spherical silica. [Formula 1] (However, in the formula, S is a specific surface area (m ²
/ G) and d are number average particle diameters (μm). ) [Formula 2] (However, D ₉₀ in the formula is a cumulative 90% by volume particle diameter, D ₁₀
Is a cumulative particle size of 10% by volume. ) 4. A silica gel is produced by reacting a hydrolyzable silicon compound with water while forming a water-in-oil emulsion in the presence of an organic solvent incompatible with water, a surfactant and a catalyst. A method for producing non-porous spherical silica, characterized in that the produced silica gel is separated and dried, and then sieving treatment is carried out using a sieve having a mesh size of 250 or more, followed by calcination.