阅读说明：本技术 分散性优异的二氧化硅粉末及使用其的树脂组合物、以及其制造方法 (Silica powder having excellent dispersibility, resin composition using same, and method for producing same ) 是由 小林清太郎 江崎寿 桥本久之 于 2018-08-07 设计创作，主要内容包括：本发明提供能够在水、溶剂、树脂中容易地分散成为一次粒子的二氧化硅粉末。二氧化硅粉末的特征在于,二氧化硅粒子表面的H-2O密度为5μg/m～2以上且80μg/m～2以下,所述H-2O密度由从25℃加热至200℃时产生的水分量算出。(The invention provides a silica powder which can be easily dispersed as primary particles in water, a solvent or a resin. The silica powder is characterized by H on the surface of the silica particles 2 O density of 5. mu.g/m 2 Above 80 μ g/m 2 Hereinafter, said H 2 The O density was calculated from the amount of water generated when heating from 25 ℃ to 200 ℃.)

1. Silicon dioxide powder, characterized in that H on the surface of the silicon dioxide particles₂O density of 5. mu.g/m²Above 80 μ g/m²Hereinafter, said H₂The O density was calculated from the amount of water generated when heating from 25 ℃ to 200 ℃.

2. Silica powder according to claim 1, wherein one or more of the following is satisfied:

the silica particles had a specific surface area of 3m²More than 50 m/g²The ratio of the total carbon content to the total carbon content is below g;

a volume average particle diameter calculated by a laser diffraction particle size distribution analyzer is 0.05 to 2.0 [ mu ] m; and

the value of (average particle diameter before dispersion in water or methyl ethyl ketone/average particle diameter after dispersion) is 1.50 or less.

3. Silicon dioxide powder according to claim 1 or 2, characterised in that it consists of from 200 ℃ CThe hydrogen bond OH group density calculated from the water content at 550 deg.C was 0.5 pieces/nm²Above and 3/nm²The following.

4. A resin composition comprising the silica powder according to any one of claims 1 to 3.

5. A method for producing a silica powder, comprising the steps of:

heating and reacting metallic silicon to obtain spherical silica powder in a high-temperature state higher than the dew point and boiling point of water;

recovering the spherical silica powder at a high temperature higher than the dew point and boiling point of water, and cooling the spherical silica powder in an atmosphere substantially free of water to a low temperature lower than the dew point and boiling point of water; and

subjecting the cooled H on the surface of the silica particles contained in the spherical silica powder₂O density of 5. mu.g/m²Above 80 μ g/m²The following steps are carried out to preserve the composition in a moisture-proof environment.

6. A method for producing a silica powder, comprising the steps of:

heating and reacting metallic silicon to obtain spherical silica powder in a high-temperature state higher than the dew point and boiling point of water;

recovering the spherical silica powder at a high temperature higher than the dew point and boiling point of water, at a temperature of 40 ℃ or lower and an absolute humidity of 40g/m³A step of cooling the glass in an atmosphere of less than 170 hours; and

subjecting the cooled H on the surface of the silica particles contained in the spherical silica powder₂O density of 5. mu.g/m²Above 80 μ g/m²The following steps are carried out to preserve the composition in a moisture-proof environment.

Technical Field

The present invention relates to a silica (silica) powder having excellent dispersibility in water and a solvent, and a resin composition using the same.

Background

In recent years, with the increase in speed, size, weight, and performance of electronic devices, printed wiring boards have been developed in accordance with the miniaturization of high-density mounting and wiring. In the insulating layer constituting the wiring board, silica powder or the like is used as a filler for the purpose of preventing cracks from occurring due to a difference in thermal expansion coefficient between the insulating layer and the copper wiring or the IC chip, and improving reliability such as moisture resistance.

As a method for producing such an insulating material, the following methods are generally known: a resin composition is produced by dispersing an inorganic filler such as silica powder in a solvent to prepare a slurry or directly dispersing the inorganic filler in a resin material, followed by molding, curing and final molding.

As the demand for fillers tends to be reduced, the size of fillers used in resin compositions has become smaller as insulating layers have become thinner, and therefore, there is a very high demand for reducing the size and content of aggregated particles to improve dispersibility. Aggregation affects the dispersion time in a solvent, a resin, or the like, the occurrence of appearance defects, and the like, and causes a decrease in productivity and a decrease in quality.

As a method for improving dispersibility, many methods have been proposed for improving silanol group density, particle size distribution, and a method for uniformly surface-treating a silica powder with a silane coupling agent (for example, patent document 1). However, the handling of the adsorbed water which affects the aggregating power is insufficient, and the dispersibility of silica itself is problematic. Of course, silica obtained by surface-treating these materials also has the same problem.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2011-213514

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a silica powder which can be easily dispersed as primary particles in water, a solvent, and a resin.

Means for solving the problems

In order to solve the above problems, embodiments of the present invention may provide the following.

(1) Silicon dioxide powder, characterized in that H on the surface of the silicon dioxide particles₂O density of 5. mu.g/m²Above 80 μ g/m²Hereinafter, said H₂The O density was calculated from the amount of water generated when heating from 25 ℃ to 200 ℃.

(2) The silica powder according to (1), wherein one or more of the following are satisfied:

the silica particles had a specific surface area of 3m²More than 50 m/g²The ratio of the total carbon content to the total carbon content is below g;

a volume average particle diameter calculated by a laser diffraction particle size distribution analyzer is 0.05 to 2.0 [ mu ] m; and

the value of (average particle diameter before dispersion in water or methyl ethyl ketone/average particle diameter after dispersion) is 1.50 or less.

(3) The silica powder according to (1) or (2), wherein the density of hydrogen bond OH groups calculated from the amount of water when heated from 200 ℃ to 550 ℃ is 0.5 pieces/nm²Above and 3/nm²The following.

(4) A resin composition comprising the silica powder according to any one of (1) to (3).

(5) A method for producing a silica powder, comprising the steps of:

heating and reacting metallic silicon to obtain spherical silica powder in a high-temperature state higher than the dew point and boiling point of water;

recovering the spherical silica powder at a high temperature higher than the dew point and boiling point of water, and cooling the spherical silica powder in an atmosphere substantially free of water to a low temperature lower than the dew point and boiling point of water; and

the cooled H on the surface of the silica particles contained in the spherical silica powder₂O density of 5. mu.g/m²Above 80 μ g/m²The following steps are carried out to preserve the composition in a moisture-proof environment.

(6) A method for producing a silica powder, comprising the steps of:

heating and reacting metallic silicon to obtain spherical silica powder in a high-temperature state higher than the dew point and boiling point of water;

recovering the spherical silica powder at a high temperature higher than the dew point and boiling point of water, at a temperature of 40 deg.C or lower and an absolute humidity of 40g/m³A step of cooling the glass in an atmosphere of less than 170 hours; and

the cooled H on the surface of the silica particles contained in the spherical silica powder₂O density of 5. mu.g/m²Above 80 μ g/m²The following steps are carried out to preserve the composition in a moisture-proof environment.

ADVANTAGEOUS EFFECTS OF INVENTION

The silica powder according to the embodiment of the present invention has the above-described configuration, and therefore can be easily dispersed as primary particles in water, a solvent, and a resin.

Detailed Description

In the present specification, unless otherwise specified, a numerical range includes its upper limit and its lower limit.

The silica powder according to the embodiment of the present invention is preferably a powder having a shape close to a spherical shape and not having a structure (not aggregated) in which primary particles are connected to each other. More specifically, the degree of aggregation can be quantitatively confirmed based on the ratio of the average particle diameters before and after dispersing the silica powder in a solvent (water, methyl ethyl ketone, etc.). In a preferred embodiment, the value of (average particle diameter before dispersion in water or methyl ethyl ketone/average particle diameter after dispersion) may be 1.50 or less, more preferably 1.30 or less, and still more preferably 1.20 or less. The degree of "sphericity" is preferably 0.85 or more in average sphericity, and the average sphericity may be measured by inputting a particle image captured by a stereo microscope, for example, a "Model SMZ-10 type" (manufactured by NIKON CORPORATION), a scanning electron microscope, a transmission electron microscope, or the like, into an image analysis device, for example, (manufactured by Nippon avinics co., ltd., or the like) as follows. That is, the projected area (a) and the Perimeter (PM) of the particles were measured from the photographs. Assuming that the area of the perfect circle with respect to the circumferential length (P M) is (B), the degree of roundness of the particle can be expressed as a/B. Therefore, it is assumed that the sample particle has the same circumferential length as the circumferential length (PM) of the sample particleWhen the circle is perfect, PM is 2 pi r and B is pi r²Thus, B ═ π × (PM/2 π)²The sphericity of each particle may be defined as a sphericity a/B a × 4 pi/(PM)²The method (2) is calculated. The sphericity of any 200 particles thus obtained can be determined and the average value thereof can be regarded as the average sphericity. The method for producing such spherical silica can be produced, for example, by the following method: a method of introducing metal silicon particles into a high-temperature field formed by a chemical flame, an electric furnace, or the like to cause an oxidation reaction and spheroidizing the particles (for example, japanese patent No. 3229353); a method in which a slurry of metal silicon particles is sprayed into a flame to perform an oxidation reaction and spheroidized (for example, japanese patent No. 3853137); and so on. The silica powder produced by the gas-phase pyrolysis method of a silicon halide is not preferable because the particles form a structure. The average particle diameter, specific surface area, and hydrogen bonding OH group density can be controlled by adjusting parameters such as metal silicon concentration and water vapor amount in the reaction vessel during production. However, H for the surface of the silica particles₂The O density cannot be stabilized at a low level within a target range only by controlling the reaction field. Silica powder trapped at high temperature by BF or the like needs to be produced by a production method taking into consideration the risk of moisture adsorption, and has not been carried out so far.

The following methods can be exemplified as a manufacturing method for coping with the above-described risk: the spherical silica powder produced by the above known method is recovered in a state of high temperature (e.g., more than 100 ℃, for example, 200 ℃) higher than the dew point and boiling point of water, cooled to a temperature lower than the dew point and boiling point of water (e.g., cooled to 100 ℃ or less, for example, cooled to room temperature) in an atmosphere in which water is as little as possible (i.e., an atmosphere in which water adsorbed to the silica powder is substantially absent), such as an atmosphere replaced with an inert gas or dry Air (Air), under reduced pressure, vacuum, and recovered in a moisture-proof environment (e.g., a moisture-proof bag made of aluminum or the like). The method is based on the following insights: in a state where the temperature of the silica powder is higher than the dew point and boiling point of water, even if a small amount of water molecules are adsorbed on the surface of the silica particles, the water molecules are immediately vaporized, and aggregation of the silica particles can be suppressed.

Alternatively, as another manufacturing method, the following method may be exemplified: at a temperature of 40 deg.C or below and an absolute humidity of 40g/m³In the following atmosphere (for example, in an atmospheric atmosphere (assuming an atmospheric temperature of 25 ℃ and a relative humidity of 60%)), the hot spherical silica powder produced by the above-described known method is cooled to a temperature of 100 ℃ or lower, and then recovered in a moisture-proof environment (a moisture-proof bag made of aluminum or the like) for a period of less than 170 hours, preferably for a period of less than one week. The manufacturing method is based on the following findings: at a temperature of 40 deg.C or below and an absolute humidity of 40g/m³In the following atmosphere, when the temperature of the silica powder is 100 ℃ or lower, the amount of adsorbed moisture to the surface of the silica particles increases with time, but it takes one week in the atmosphere before the amount of adsorbed moisture reaches the amount of adsorbed moisture in which the silica particles are aggregated.

Needless to say, the production method is not limited to the above method as long as the production method suppresses the risk of adsorption of moisture.

In the silica powder produced by the above-exemplified production method, H on the surface of the silica particles is calculated from the amount of moisture generated when heated from 25 ℃ to 200 ℃₂O density of 5. mu.g/m²Above 80 μ g/m²The following. More preferably, the silica particles may have a specific surface area of 3m²More than 50 m/g²(ii)/g or less, and the volume average particle diameter calculated by a laser diffraction particle size distribution analyzer is 0.1 to 2.0 [ mu ] m.

H on the surface of the silica particles₂O density of 5. mu.g/m²Above 80 μ g/m²Below, if it exceeds 80. mu.g/m²Then, silica aggregates are generated or the probability of generation is increased due to liquid crosslinking, and the dispersibility in water, a solvent, or a resin is lowered. H on the surface of the silica particles₂The preferable range of the O density is 5. mu.g/m²Above, 50 mu g/m²Hereinafter, it is more preferably 5. mu.g/m²Above, 30 mu g/m²The following.

Here, H on the surface of the silica particles₂The O density is an amount of adsorbed water per unit surface area of the silica particles, and the amount of adsorbed water is defined as a value obtained by measuring an amount of volatile water when heated from 25 ℃ to 200 ℃ by the karl fischer method. Namely, the following values: the value obtained by putting a sample into an empty-fired alumina boat using a measuring apparatus (for example, "micro water content measuring apparatus CA-06" manufactured by mitsubishi chemical corporation), putting the boat into a furnace maintained at a constant temperature of 25 ℃, and then quantifying the water volatilized when the boat is heated to 200 ℃ by an coulometry method. For example, "AQUAMICRON AX" manufactured by Mitsubishi chemical corporation can be used as the catholyte, and "AQUAMICRON CXU" can be used as the anolyte.

The specific surface area of the silica powder is a value based on the BET method. The specific surface area can be measured using, for example, "Macsorb HM model-1208" (manufactured by MACSORB Co., Ltd.).

The BET specific surface area value of the silicon dioxide powder is preferably 3-50 m²(ii) in terms of/g. If the BET specific surface area value is 3m²When the amount is more than g, the sedimentation rate does not become too high when the dispersion is dispersed in a solvent, and the storage stability can be ensured. In addition, if the BET specific surface area value is 50m²Less than g, the production of silica aggregates can be suppressed.

The volume average particle diameter of the silica powder is preferably 0.05 to 2.0 μm. When the volume average particle diameter is 2.0 μm or less, the sedimentation rate does not become too high when the dispersion is dispersed in a solvent, and the storage stability can be ensured. When the volume average particle diameter is 0.05 μm or more, generation of silica aggregates can be suppressed. The volume average particle diameter may preferably be in the range of 0.1 to 1.2 μm.

The volume average particle diameter of the silica powder is a value based on particle size measurement by a laser diffraction light scattering method, and can be measured with a particle size distribution measuring instrument, for example, using "Model LS-230" (manufactured by Beckman Coulter inc.).

The density of hydrogen-bonding OH groups of the silicon dioxide powder is preferably 0.5 atoms/nm²Above, 3/nm²The following. The hydrogen bondThe density of the OH groups is 3/nm²When the amount of the surfactant is less than the above range, the compatibility (wettability) with a solvent or a resin becomes good, and the amount of the surfactant is 0.5 molecules/nm²In the above case, the compatibility (wettability) with water is improved. The preferred range of the density of the hydrogen bonding OH groups can be 1-2.5/nm²。

Here, the density of hydrogen-bonding OH groups of the silica powder refers to the hydrogen-bonding OH groups per unit surface area of the silica particles, and is defined as a value obtained by measuring the amount of volatile moisture when heated from 200 ℃ to 550 ℃ by the karl fischer method. Namely, the following values: the value obtained by putting a sample into an empty-fired alumina boat using a measuring apparatus (for example, "micro water content measuring apparatus CA-06" manufactured by mitsubishi chemical corporation), putting the boat into a furnace, heating the boat, and quantifying water volatilized at a temperature ranging from 200 ℃ to 550 ℃ by an coulometry method. For example, "AQUA MICRON AX" manufactured by mitsubishi chemical corporation can be used as the catholyte, and "AQUA MICRON CXU" can be used as the anolyte.

Examples

Hereinafter, examples of the present invention and comparative examples will be described in more detail.

(1) Production of spherical silica powder

Spherical silica powder was produced using the following apparatus: the apparatus is provided with a burner of a triple coil structure assembled in the order of a combustible gas supply pipe, a combustion-supporting gas supply pipe, and a metal silicon powder slurry supply pipe from the outermost portion, and a classification and collection system (a blower for sucking the generated powder and a bag filter for collecting the powder) such as a cyclone, connected to the lower portion of the manufacturing furnace. In addition, 3 outer burners for forming outer flames are provided on the outer periphery of the burner. From a combustible gas supply pipe at 7Nm³LPG is supplied at a rate of 12 Nm/hr from a combustion supporting gas supply pipe³Oxygen was supplied/hr, thereby forming a high-temperature flame in the manufacturing furnace. A metallic silicon slurry prepared by dispersing metallic silicon powder in methanol is supplied from a metallic silicon powder slurry supply pipe to a flame by a slurry pump, and is swirled by a cycloneA separator or a bag filter for collecting the spherical silica powder produced in the state that the powder temperature is 110 to 200 ℃. The collected spherical silica powder was cooled to 40 ℃ in an atmospheric atmosphere (air temperature 25 ℃ C., relative humidity 60%) over 160 hours, and then collected in a moisture-proof aluminum bag. The realization of the average particle diameter and the specific surface area of the spherical silica powder is performed by controlling the metal silicon concentration in the furnace by adjusting the slurry concentration.

(2) H on the surface of the silica particles₂Adjustment of O Density and Hydrogen bonding OH group Density

H for silicon dioxide powder₂The adjustment of the O density and the hydrogen bonding OH group density was carried out by exposing the spherical silica powder to an atmosphere having a temperature of 25 ℃ and a humidity of 60% by using "EC-45 MHHP" manufactured by Hitachi applications, Inc., and adjusting the exposure time.

The methods for evaluating the physical properties of the silica powder are shown in the following (1) to (3), and summarized in tables 1 and 2.

(1) H on the surface of the silica particles₂Evaluation of O Density and Hydrogen bond OH group Density

H for the surface of silica particles₂The O density and the hydrogen bond OH group density were as follows: the amount of water generated in a predetermined temperature range was measured by the above-described method using "CA-100" manufactured by Mitsubishi chemical corporation. The hydrogen bond OH group density is calculated by the following formula.

Amount of water per unit specific surface area (. mu.g/m)²) The amount of water (μ g)/(amount of silica sample (g) × specific surface area (m) generated in a temperature region of 200 to 550 ℃²/g))

Hydrogen bond OH group density (one/nm)²) Amount of water per unit specific surface area (μ g/m)²)×6.02×10²³(one/mol). times.2X 10^-6×10^-18/18(g/mol)

[ Explanation of numerical values ]

6.02×10²³(per mol): avogalois constant

2: by 2 molecules of ODehydration of the H group to give 1 molecule of H₂O

10^-6: conversion of unit of μ g → g

10^-18：m²→nm²Unit conversion of

18 (g/mol): molecular weight of Water

(2) Evaluation of particle size of silica powder

The volume average particle diameter of the silica powder was measured by a laser diffraction light scattering method, and as a particle size measuring instrument, "Model LS-230" manufactured by Beckman Coulter Inc. was used. For the measurement, water was used as the solvent, and dispersion treatment was performed for 60 seconds by applying an output of 200W to an ultrasonic homogenizer as a pretreatment. The preparation is performed so that the concentration of PIDS (Polarization Intensity difference of Scattering) is 45 to 55 mass%. The refractive index is determined by the refractive index of the solvent used, and the refractive index of the powder is considered by the refractive index of the material of the powder. For example, the refractive index of amorphous silica is measured to be 1.50. The particle size distribution to be measured was converted so that the particle size channel had a width of log (μm) of 0.04.

(3) Specific surface area of silica powder

1.0g of silica powder was measured and put into a cell (cell) for measurement, and after pretreatment, the BET specific surface area value was measured. The measuring apparatus used was a MACSORB HM model-1208. Pretreatment conditions are shown below.

Degassing temperature: 300 deg.C

Degassing time: 18 minutes

Cooling time: 4 minutes

The methods for evaluating the dispersibility of the silica powder are shown in the following (1) and (2), and the evaluation results are summarized in tables 3 and 4.

(1) Evaluation of dispersibility in Water or MEK

The silica powder was added to water or a Methyl Ethyl Ketone (MEK) solvent, and the measurement was based on the particle size measurement described in the above section "(2) evaluation of particle size of silica powderVolume average particle diameter (D) before and after dispersion treatment in ultrasonic homogenizer₅₀) The following is performed as a reference.

◎：D₅₀(before dispersion) is less than or equal to 1.2 XD₅₀(after dispersion)

○：D₅₀(before dispersion) is less than or equal to 1.5 XD₅₀(after dispersion) and>1.2×D₅₀(after dispersion)

×：D₅₀(before dispersion)>1.5×D₅₀(after dispersion)

(2) Evaluation of dispersibility in resin

67 parts by mass of silica powder was added to 100 parts by mass of bisphenol F type liquid epoxy resin type "807" manufactured by Mitsubishi chemical CORPORATION as an epoxy resin, and the mixture was treated with a rotating and revolving mixer "ARE-310" manufactured by THINKY CORPORATION under the following conditions to prepare a resin composition.

Rotating speed: 2000rpm

Autorotation: 3 minutes

Revolution: 1 minute

With respect to the resin composition, dispersibility in a resin was evaluated by a distribution chart method using a fineness meter having a width of 90mm, a length of 240mm and a maximum depth of 100 μm in accordance with JIS-5600-2-5. The silica powders used in examples 2, 7 and 12 and comparative examples 2 and 7 were typically subjected to this evaluation.

Very good: the scale of the position where the particles start to be dense is less than 10 μm

O: the scale of the position where the particles start to be dense is 10 μm or more and less than 20 μm

X: the scale of the position where the particles start to be dense is 20 μm or more

[ Table 1]

[ Table 2]

[ Table 3]

[ Table 4]

As is clear from comparison of examples and comparative examples, the silica powder of the present invention has very high dispersibility in water, solvents, and resins.

Industrial applicability

According to the characteristics, the silica powder of the present invention, and the slurry and the resin composition using the same can be suitably used for, for example, a filler for an insulating layer used in a printed wiring board or the like in the field of electronic devices.