JP6752658B2 - Variant silica powder, its production method, resin composition containing it - Google Patents

Description

The present invention relates to a deformed silica powder, a method for producing the same, and a resin composition containing the same.

In recent years, the miniaturization, thinning, and high-density mounting of semiconductor devices have been rapidly progressing, and the gap of semiconductor mounting is becoming narrower. With the narrowing of the gap, generally, as a filler for a sealing agent for mounting a high-density semiconductor, spherical silica having a BET specific surface area of ^{2 to} 30 m ² / g and a particle size of about 0.1 to 1.5 μm in terms of primary particle size Powder is used.

When spherical silica is used as a filler, it is known that the stress in the resin after molding is low due to the smoothness of the surface thereof. It is natural that silica is blended at a high filling rate in order to improve the thermal conductivity and dimensional stability of the encapsulant, but the bending strength, adhesive strength, and solder reflow resistance are improved against the above stress reduction. From this point of view, increasing the filling of silica has been an issue.

However, silica powder having a BET specific surface area in the above range has a problem that it is difficult to suppress an increase in the viscosity of the resin composition when the resin is highly filled, and the fluidity of the resin composition is lowered. That is, when a resin composition having low fluidity is used for mounting a narrow-gap semiconductor, molding defects occur, so that there is a limit to high filling of silica.

By the way, it is known that when crushed silica is blended with spherical silica at a constant ratio as a filler, it is effective in improving fracture toughness, bending strength, solder reflow resistance and the like. However, when crushed silica is mixed, in addition to problems such as a decrease in filling rate and fluidity, the crushed surface of the crushed silica is angular, so that the surface of the semiconductor element and the wire are easily damaged. There was a problem of causing mold wear. Document 1 describes a resin composition in which the above problem is improved by filling with crushed silica powder having a specified roundness.

Japanese Unexamined Patent Publication No. 2001-146413

However, the inventors of the present application have stated that the encapsulant for high-density semiconductor mounting, in which high silica filling is an issue, has a crushed surface although the roundness is specified, and there is room for further improvement. Found.

The present invention has been made in view of the above problems, and an object of the present invention is to maintain a filling rate in a resin and to seal the resin composition with excellent bending strength, adhesive strength, and solder reflow resistance. It is to provide silica for material filling.

In order to solve the above problems, the present inventors not only maintain high filling rate and high fluidity, but also resin composition when a silica powder having specific physical properties is used as a filler for a sealing material. We have found that it is effective in bending strength, adhesive strength, and solder reflow resistance of an object, and have completed the present invention. That is, the present invention has the following configuration.

[1] The median diameter of the weight-based particle size distribution measured by the centrifugal sedimentation method is in the range of 50 to 1000 nm, and the area (S) obtained by the image analysis method and the entanglement area (S ₀ ) obtained by the image analysis method. The ratio (S / S ₀ ) to) is in the range of 0.60 to 0.95, the maximum (peak) of the weight-based particle size distribution obtained by the centrifugal sedimentation method is one, and the geometric standard deviation σg. Is 1.5 or less, and the saturated water content measured by the drying weight loss method at 120 ° C. is 1.5% by mass or less.

[2] The modified silica powder according to [1], wherein the average circularity of the particles obtained by the image analysis method is in the range of 0.40 to 0.85.

[3] The modified silica powder according to [1] or [2], wherein the content of particles having a circularity of 0.95 or more and 5% by number or less obtained by an image analysis method is used.

[4] The modified silica powder according to any one of [1] to [3], wherein the contents of sodium, potassium and iron are each less than 1 ppm.

[5] The modified silica powder according to any one of [1] to [4], which has hydrophobicity.

[6] A resin composition containing the modified silica powder according to any one of [1] to [5].

[7] An alkoxysilane or a hydrolyzate thereof and / or a partial condensate thereof is added to a fumed silica dispersion liquid and subjected to a polycondensation reaction to obtain a reaction liquid in which irregularly shaped silica particles are suspended, and the obtained reaction liquid is used. A method for producing a deformed silica powder, which comprises a step of recovering the deformed silica particles, a step of firing the recovered deformed silica particles, and a step of crushing the deformed silica particles obtained by the firing step.

[8] The method for producing a deformed silica powder according to [7], further comprising a step of hydrophobizing the surface of the obtained deformed silica particles.

[9] A core-shell type variant silica powder composed of a core portion and a shell portion covering the core portion, wherein the core portion is made of fumed silica and the shell portion is obtained by a sol-gel method. A modified silica powder which is a silica layer and has a saturated water content of 1.5% by mass or less as measured by a drying weight loss method at 120 ° C.

[10] The modified silica powder according to claim 9, wherein the surface of the shell portion is surface-treated.

According to the present invention, when it is used as a filler for a semiconductor encapsulant, it does not cause damage to the surface of the semiconductor element or the wire or wear of the mold, and the resin after molding has bending strength, adhesive strength, and solder resistance. Since it has excellent reflowability, it is suitably used for various electric and electronic parts.

It is a figure which shows the deformed silica powder which concerns on one Embodiment of this invention. It is a figure which shows an example of the graph which shows the weight-based particle size distribution. It is a schematic diagram which shows the acquisition method of the area (S) obtained by an image analysis method, and the envelope area (S ₀ ) obtained by an image analysis method. It is the schematic which compared the manufacturing method of the deformed silica powder which concerns on one Embodiment of this invention, and the manufacturing method of the conventional spherical silica powder. It is the schematic which compared the manufacturing method of the deformed silica powder which concerns on one Embodiment of this invention, and the manufacturing method of the conventional deformed silica powder. FIG. 1 is a diagram illustrating a method of measuring the adhesive strength after curing of a resin in a resin composition obtained by adding metal oxide particles to an acrylic resin, which was carried out in each example of the present application.

Embodiments of the present invention will be described in detail below. For convenience of explanation, the same reference numerals will be added to the members having the same function, and the description thereof will be omitted. Unless otherwise specified in the present specification, "A to B" representing a numerical range means "A or more (including A and larger than A) and B or less (including B and smaller than B)".

[1. Variant silica powder]
First, the outline of the modified silica powder will be described below. In addition, in this specification, "silica powder" is intended as an aggregate of silica particles having a particle size distribution, and includes "silica particles". In the present specification, the expression "silica powder" is used to describe the state after drying and the particle size distribution, and the expression "silica particles" is used to describe the state or the number of particles dispersed in the liquid. There is also.

FIG. 1 is a diagram showing a deformed silica powder according to an embodiment of the present invention. FIG. 1 shows an image acquired by a scanning electron microscope (SEM). As will be described later, this deformed silica powder is obtained by using beaded particles as nuclei and growing the particles. In other words, it can be said that the modified silica powder is obtained by growing the secondary particles obtained by fusing the spherical primary particles as nuclei. Therefore, as shown in FIG. 1, the deformed silica powder is a deformed silica powder, which does not substantially contain spherical silica particles and does not substantially have an angular shape such as a crushed surface. Is.

As used herein, the term "variant" means that it is not spherical (non-spherical). Since this modified silica powder has the configuration described in the embodiment described later, it can maintain a high filling rate when used as a filler for a semiconductor encapsulant, so that it has thermal conductivity, dimensional stability, and solder resistance. It has excellent reflowability, and has excellent bending strength and adhesive strength without causing damage to the surface of semiconductor elements or wires or wear of molds.

Hereinafter, each configuration of the modified silica powder will be described in detail.

[Embodiment 1]
In this modified silica powder, the median diameter of the weight-based particle size distribution measured by the centrifugal sedimentation method is in the range of 50 to 1000 nm, and the area (S) obtained by the image analysis method and the entanglement area obtained by the image analysis method. _{(S 0)} and the ratio of (S / _{S 0)} is in the range of 0.60 to 0.95, is one local maximum (peak) of the weight particle size distribution obtained by centrifugal sedimentation, and geometric The standard deviation σg is 1.5 or less, and the saturated water content measured by the drying weight loss method at 120 ° C. is 1.5% by weight or less. The S / S ₀ indicates the degree of unevenness on the surface of the modified silica powder. The physical properties of the modified silica powder will be described in detail below.

<1-1. Median diameter of weight-based particle size distribution>
The modified silica powder has a median diameter in the range of 50 to 1000 nm in the weight-based particle size distribution measured by the centrifugal sedimentation method. The median diameter is preferably 120 nm or more, more preferably 250 nm or more, and even more preferably 300 nm or more. The median diameter is preferably 500 nm or less.
Within the above numerical range, it can be suitably used as a filler for a semiconductor encapsulant.

In the present specification, the median diameter of the weight-based particle size distribution by the centrifugal sedimentation method is that of dispersed particles obtained by dispersing deformed silica powder in a dispersion medium at a concentration of 1.5 mass% at an output of 20 W and a dispersion time of 45 minutes. It means the median diameter of the weight-based particle size distribution. As the dispersion medium, water is used in the case of hydrophilic variant silica, and 2-propanol is used in the case of hydrophobic variant silica.

An example of a particle size distribution measuring machine used in the centrifugal sedimentation method is a CPS disk centrifugal sedimentation type particle size distribution measuring device DC-24000.

<1-2. Concavity and convexity>
In this modified silica powder, the ratio (S / S ₀ ) of the area (S) obtained by the image analysis method to the enveloping area (S ₀ ) obtained by the image analysis method is 0.60 to 0.95. It is in the range. In the present specification, the ratio (S / S ₀ ) of the area (S) obtained by the image analysis method and the envelope area (S ₀ ) obtained by the image analysis method is also referred to as a degree of unevenness. The closer the degree of unevenness is to 1, the smaller the degree of unevenness (that is, the closer to a state without unevenness).

When the degree of unevenness is 0.95 or less, the deformed silica powder has sufficient unevenness, so that the bending strength and the adhesive strength of the molded resin are improved when used as a semiconductor encapsulant. .. The smaller the value of the degree of unevenness, the greater the unevenness of the particles, which contributes to the mechanical strength and the adhesive strength, but if it is too small, the fluidity of the resin composition tends to decrease. Usually, it is 0.60 or more.

The degree of unevenness is preferably 0.93 or less, more preferably 0.90 or less, and further preferably less than 0.90. The degree of unevenness is preferably 0.60 or more, and more preferably 0.70 or more.

Further, in the present modified silica powder, the content of particles having an unevenness of 0.97 or more is preferably 10% by number or less, more preferably 7% by number or less, and 6% by number or less. Is even more preferable. When the content of the particles having an unevenness of 0.97 or more is 10% by number or less, the content of the particles having no unevenness is extremely small, which is preferable.

In the present specification, the degree of unevenness obtained by the image analysis method is determined by taking an image of 500 or more silica particles and analyzing the image to obtain the area (S) of each particle and the convexity of each particle. The envelopment area (S ₀ ) surrounded by the envelope connecting the portions was obtained, and the ratio (S / S ₀ ) between the area of each particle and the envelopment area was calculated and averaged.

Specifically, for the area (S) and the entanglement area (S ₀ ), a bright field-scanning transmission image (BF-STEM) of silica particles is photographed using FE-SEM, and the photographed photograph is image analysis software. It can be obtained by incorporating it into "A image-kun" (manufactured by Asahi Kasei Engineering Co., Ltd.) and performing particle analysis.

FIG. 3 is a schematic view showing a method of acquiring the area (S) obtained by the image analysis method and the envelope area (S ₀ ) obtained by the image analysis method. In FIG. 3, the area of the particle 16 obtained by the image analysis method is S, and the area inside the envelope 17 connecting the convex portions of the particle 16 is S ₀ .

In this specification, the content of particles having an unevenness of 0.97 or more obtained by an image analysis method means the number ratio of particles having an unevenness of 0.97 or more.

<1-3. Maximum (peak) and geometric standard deviation σg of weight-based particle size distribution>
The modified silica powder has one maximum (peak) of the weight-based particle size distribution obtained by the centrifugal sedimentation method, and the geometric standard deviation σg is 1.50 or less. The geometric standard deviation σg represents the width of the particle size distribution. The closer the value of the geometric standard deviation σg is to 1, the narrower the particle size distribution and the sharper the maximum.

FIG. 2 is a diagram showing an example of a graph showing a weight-based particle size distribution. As illustrated in FIG. 2, the modified silica powder has one maximum (peak) of the weight-based particle size distribution. On the other hand, the conventional irregularly shaped silica powder is generally obtained by aggregating spherical fine silica particles and then growing the particles. Therefore, the large-grained spherical silica particles derived from the non-aggregated silica particles are produced. It will be included in a certain amount. That is, since it contains spherical silica particles and non-spherical silica particles, the particle size distribution is broad. Therefore, the weight-based particle size distribution of the conventional silica powder becomes wider than that in FIG. 2 (that is, the geometric standard deviation σg becomes larger), and / or the maximum (peak) of the weight-based particle size distribution becomes a plurality. Therefore, by using this weight-based particle size distribution as an index, it can be seen that the present modified silica powder is different from the conventional modified silica powder.

Further, the geometric standard deviation σg is more preferably 1.45 or less, further preferably 1.42 or less, further preferably 1.40 or less, and particularly preferably 1.38 or less. preferable. Within such a range, since it does not contain coarse particles that cause molding defects in narrowing the gap and fine particles that cause an increase in viscosity, it is suitably used as a filler for a sealing agent for mounting high-density semiconductors. it can.

In the present specification, the maximum of the weight-based particle size distribution by the centrifugal sedimentation method is the condition that the deformed silica powder is output at a concentration of 1.5% by mass at an output of 20 W and the dispersion time is 45 minutes, similar to the median diameter of the weight-based particle size distribution described above. Means the maximum weight-based particle size distribution of the dispersed particles obtained by dispersing them in a dispersion medium. As the dispersion medium, water is used in the case of hydrophilic variant silica, and 2-propanol is used in the case of hydrophobic variant silica. Further, in the present specification, the geometric standard deviation σg of the particle size distribution is obtained by logarithmic mean distribution fitting (least squares method) of the weight-based particle size distribution obtained as described above in a cumulative frequency range of 10% by mass to 90% by mass. , Means the value calculated from the fitting.

<1-4. Saturated water content>
The modified silica powder has a saturated water content of 1.5% by mass or less as measured by a drying weight loss method at 120 ° C. The smaller the saturated water content, the better the long-term storage stability of the resin composition when used as a filler for a sealing material. When a resin composition filled with silica having a large saturated water content is stored for a long period of time, the resin or the substrate after molding may crack and the yield may decrease.

Therefore, the smaller the saturated water content, the more preferably 1.0% by mass or less, further preferably 0.5% by mass or less, but usually 0.1% by mass or more.

In the present specification, it means the value obtained by the saturated water content method. After drying 10 g of silica particles at 120 ° C. for 24 hours, the particles were cooled in a desiccator containing silica gel. Subsequently, the particles cooled in the desiccator were allowed to stand in an environment of 25 ° C. and 50% RH for 48 hours, and the mass (Dwet) of the particles was weighed. The weighed particles were dried again at 120 ° C. for 24 hours and the mass of the particles (Ddry) was weighed. From the mass change before and after humidity control, the value calculated by the following mathematical formula (2) was defined as the saturated water content.

Saturated water content = ((Dwet-Ddry) / Ddry (2))
<1-5. Circularity and average circularity>
The irregularly shaped silica powder preferably has an average circularity of particles obtained by an image analysis method in the range of 0.40 to 0.85. In the present specification, the "circularity" is calculated for each particle, and the "average circularity" is intended to be a value obtained by calculating the average circularity of the powder (aggregate of particles). The closer the circularity is to 1, the closer it is to a sphere. That is, from the circularity, the degree of deformation (that is, the degree of non-spherical shape) of the present deformed silica powder can be known.

Further, the closer the average circularity is to 1, the larger the proportion of nearly spherical particles contained in the powder.

The average circularity is more preferably 0.80 or less, and further preferably 0.75 or less. Further, the average circularity is more preferably 0.50 or more, and further preferably 0.55 or more.

In this modified silica powder, the content of particles having a circularity of 0.95 or more obtained by an image analysis method is preferably 5% by number or less, more preferably 3% by number or less, and 1% by number. The following is more preferable. When the content of the particles having a circularity of 0.95 or more is 5% by number or less, the content of particles having a nearly spherical shape is small, which is preferable.

In the present specification, the average circularity of the particles obtained by the image analysis method is such that the area (S) of the individual particles and the individual silica are obtained by taking an image of 500 or more silica particles and analyzing the image. The perimeter of the particles was determined, and the circularity of each particle was calculated from the following equation (1) and averaged.

Circularity = 4π x area / (peripheral length) ² (1)
Specifically, as for the circularity, the bright field-scanning transmission image (BF-STEM) is photographed for each silica particle using FE-SEM, and the photographed photograph is image analysis software. It can be obtained as circularity 2 by incorporating it into "A image-kun" (manufactured by Asahi Kasei Engineering Co., Ltd.) and performing particle analysis.

In the present specification, the content of the particles having a circularity of 0.95 or more obtained by the image analysis method means the number ratio of the particles having a circularity of 0.95 or more.

<1-6. Aspect ratio>
The aspect ratio of the modified silica powder obtained by the image analysis method is preferably 4.0 or less, more preferably 3.0 or less, and further preferably 2.0 or less. Moreover, the aspect ratio is preferably more than 1.2.

When the aspect ratio is 4.0 or less, the viscosity does not increase during synthesis and it is easy to handle, which is preferable. Further, even in the resin composition filled with the irregularly shaped particles, the viscosity does not increase and the fluidity is maintained. If it exceeds 1.2, it contributes to the bending strength and the adhesive strength of the resin after molding.

In the present specification, the aspect ratio obtained by the image analysis method is the maximum length between any two points of individual particles by taking an image of 500 or more silica particles and analyzing the image. The maximum length and the minimum width, which is the width in the direction perpendicular to the maximum length, are obtained, calculated as the ratio of the maximum length to the minimum width (maximum length / minimum width), and averaged.

Specifically, the ratio of the maximum length to the minimum width is determined by taking a bright field-scanning transmission image (BF-STEM) for each silica particle using FE-SEM, and using the image analysis software "BF-STEM" as the photograph. It can be determined as the maximum / minimum by incorporating it into "A image-kun" (manufactured by Asahi Kasei Engineering Co., Ltd.) and performing particle analysis.

<1-7. Content of metal impurities>
The modified silica powder preferably has a low content of metal impurities. If the content of metal impurities is small, it is possible to suppress the occurrence of problems such as short circuits of metal wiring when mounted on a semiconductor device as a sealing material.

Specifically, the variant silica powder preferably has a sodium, potassium, and iron content of less than 1 ppm each.

Further, in the conventional deformed silica, a metal salt or the like may be used as a coagulant in order to agglomerate spherical primary particles to obtain deformed secondary particles. In this case, the amount of metal impurities becomes relatively large. On the other hand, as described later, this deformed silica powder is obtained by grain growth centered on the deformed silica, and therefore does not require a flocculant. Therefore, the modified silica powder has an extremely low content of metal impurities as described above.

As used herein, the content of sodium and potassium means values measured using an ion chromatography system. Further, the iron content means a value measured using an ICP emission spectrometer.

<1-8. Degree of hydrophobization (M value)>
The modified silica powder can also be made hydrophobic by the hydrophobic treatment described later. The degree of "hydrophobicity" can also be expressed using the degree of hydrophobicity. In addition, in this specification, the degree of hydrophobization may be referred to as an M value.

The degree of hydrophobization is preferably 30% by volume or more, and more preferably 35 to 76% by volume. If the degree of hydrophobization is within this range, it means that the surface of the present hydrophobic variant silica powder is sufficiently hydrophobized. When the hydrophobic variant silica powder is added to the hydrophobic resin, it is guaranteed that the surface of the hydrophobic variant silica powder is completely wet and dispersed in the resin without showing non-uniformity such as phase separation.

If the degree of hydrophobization is within this range, it means that the surface of the present hydrophobic variant silica powder is sufficiently hydrophobized. When the hydrophobically shaped silica powder of the present invention is added to a hydrophobic resin, the surface of the hydrophobically shaped silica powder of the present invention is completely wet and dispersed in the resin without showing non-uniformity such as phase separation. Guarantee.

In the present specification, the degree of hydrophobization means a value obtained by the following method. After weighing 50 mL of water in a beaker having a capacity of 200 mL, 0.2 g of a silica powder sample was put into the beaker. While stirring this with a magnetic stirrer, methanol was added dropwise with a burette, and titration was carried out starting from the point where the entire amount of the added silica powder was wetted with the solvent in the beaker and suspended. At this time, the silica powder sample was introduced into the solvent using a tube so that the methanol would not come into direct contact with the sample. Then, the value of the volume% of methanol in the methanol-water mixed solvent at the end point of the titration was defined as the degree of hydrophobicity (M value).

<1-9. True specific gravity>
The true specific gravity of the modified silica powder is preferably in the range of 1.80 to 2.17. The same applies to the above-mentioned amorphous silica powder having hydrophobicity. The fact that the true specific gravity is in this range indicates that the specific gravity is smaller than that of general dry silica. Generally, silica obtained by the sol-gel method has a smaller true specific gravity than dry silica. The true specific gravity is a value measured by a dry automatic density meter.

[Embodiment 2]
Further, in another aspect, the present modified silica powder is a core-shell type modified silica powder composed of a core portion and a shell portion covering the core portion, and the core portion is made of fumed silica. The shell portion may be a silica layer obtained by the sol-gel method, and the saturated water content measured by the drying weight loss method at 120 ° C. may be 1.5% by mass or less. This modified silica powder has a structure obtained by forming a deformed fumed silica as a core portion and growing grains thereof. Therefore, the present variant silica powder is variant and does not contain substantially spherical silica particles.

Fumed silica is a type of dry silica, and generally has a complicated shape formed by fusing primary particles in a beaded shape. In the present invention, the fumed silica serving as the core portion is not particularly limited, and known ones can be used.

For example, the BET specific surface area of the fumed silica is preferably 70 to 330 m ² / g. The average primary particle size of the fumed silica is preferably 7 to 22 nm. It may be appropriately selected according to the target particle size.

The shell portion is a silica layer obtained by the sol-gel method as described above. In the present specification, the “sol-gel method” is referred to as, for example, [2. Method for Producing Deformed Silica Powder] <2-1. It means the method described in the process of producing silica powder>.

The saturated water content is <1-4. Saturated water content> is as described.

In the present invention, the surface of the shell portion may be further surface-treated. The surface treatment is described in, for example, [2. Method for Producing Deformed Silica Powder] <2-7. A state in which the surface is treated by the method described in Surface Treatment> can be mentioned.

Further, as shown in the first embodiment, the modified silica powder has a median diameter in the range of 50 to 1000 nm of the weight-based particle size distribution measured by the centrifugal sedimentation method, and the area (S) obtained by the image analysis method. ) And the entanglement area (S ₀ ) obtained by the image analysis method (S / S ₀ ) is in the range of 0.60 to 0.95, and the maximum weight-based particle size distribution obtained by the centrifugal sedimentation method is maximized. Deformed silica powder having one (peak) and a geometric standard deviation σg of 1.5 or less may also be included. That is, the modified silica powder may also include the modified silica powder having each physical property shown in the first embodiment.

[2. Method for manufacturing irregularly shaped silica powder]
In the method for producing the modified silica powder (hereinafter, also simply referred to as “the present production method”), alkoxysilane or a hydrolyzate thereof and / or a partial condensate thereof are added to a fumed silica dispersion and subjected to a polycondensation reaction. Includes the step of producing silica particles. That is, the present production method may include a step of growing grains using fumed silica, which is a variant, as a core. The silica powder obtained by this production method has a variant shape. Furthermore, the content of spherical silica particles in the obtained deformed silica powder is extremely low.

That is, according to the present manufacturing method, the above-mentioned [1. Deformed silica powder] can be obtained. In addition, [1. Regarding the matters already explained in [Variant silica powder], the description thereof will be omitted below, and the above description will be incorporated as appropriate.

FIG. 4 is a schematic view comparing a method for producing a deformed silica powder according to an embodiment of the present invention with a conventional method for producing spherical silica powder. FIG. 4A shows a conventional method for producing spherical silica powder. FIG. 4B shows a method for producing a deformed silica powder according to an embodiment of the present invention.

The silica powder is obtained, for example, by a reaction in which SiOH ₄ is obtained by hydrolysis from Si (OCH ₃ ) ₄ and SiO ₂ is obtained by polycondensation. In the conventional method for producing spherical silica powder, first, as shown in (i) of FIG. 4A, a reaction solution 18 containing a basic catalyst, a solvent and the like is charged. Then, as shown in (ii) of FIG. 4A, a basic catalyst, alkoxysilane and the like are added, and nucleation particles 19 are generated by a nucleation reaction. Then, as shown in (iii) of FIG. 4A, spherical silica particles 15 having an increased particle size are obtained by a nuclear growth reaction. On the other hand, in the case of this production method, as shown in (i) of FIG. 4 (b), irregularly shaped fumed silica is used as the nuclear particles (starting material). In this production method, as shown in (ii) of FIG. 4 (b), first, the irregularly shaped nuclear particles 20 are charged together with the reaction solution 18. Then, as shown in (iii) of FIG. 4 (b), the deformed silica powder (deformed silica particles) 1 having an increased particle size is obtained by the nuclear growth reaction.

FIG. 5 is a schematic view comparing a method for producing a deformed silica powder according to an embodiment of the present invention with a conventional method for producing a deformed silica powder. FIG. 5A shows a conventional method for producing a deformed silica powder. FIG. 5B shows a method for producing a deformed silica powder according to an embodiment of the present invention.

In the conventional method for producing irregularly shaped silica powder, first, spherical nuclear particles are generated as shown in (i) of FIG. 5 (a). Then, as shown in (ii) of FIG. 5A, the spherical nuclear particles are aggregated. Then, as shown in (iii) of (a) of FIG. 5, irregularly shaped silica particles having a large particle size are obtained by grain growth. However, in this case, a certain amount of spherical silica particles having a large particle size, which are derived from the spherical nuclear particles that did not aggregate, remain. Therefore, in the conventional method for producing irregularly shaped silica powder, the particle size distribution becomes wide as described above. The techniques described in Patent Documents 2 and 3 described above correspond to the manufacturing method shown in FIG. 5 (a). On the other hand, in the case of this production method, as shown in (i) of FIG. 5 (b), irregularly shaped fumed silica is used as the nuclear particles. Then, as shown in (ii) of FIG. 5 (b), by growing the nuclei particles, irregularly shaped silica particles having an increased particle diameter are obtained. Therefore, in the case of this production method, the content of spherical silica particles is extremely low.

<2-1. Process for manufacturing silica particles>
In this step, alkoxysilane or a hydrolyzate thereof and / or a partial condensation product thereof is added to a fumed silica dispersion and subjected to a polycondensation reaction to produce silica particles. That is, in this step, fumed silica is grown into grains by the sol-gel method to obtain a reaction solution in which irregularly shaped silica particles are suspended. In this step, since fumed silica is used as nuclear particles, irregularly shaped silica particles can be obtained. Further, since the spherical silica particles are not used as nuclei particles, the content of the spherical silica particles in the obtained deformed silica powder is extremely small.

The dispersibility index of the fumed silica dispersion is preferably 2.5 or more, more preferably 2.6 or more, further preferably 2.7 or more, and 2.8 or more. Is particularly preferred. When the dispersibility index is 2.5 or more, fumed silica is sufficiently dispersed in the dispersion liquid without agglutination, which is preferable. In this specification, the dispersibility index means a value measured by the method described in Examples described later.

(Humeed silica)
The fumed silica contained in the fumed silica dispersion is described in [1. The fumed silica described in [Atypical silica powder] is not particularly limited.

(solvent)
Examples of the solvent in the fumed silica dispersion include a polar solvent. As used herein, the polar solvent means water or an organic solvent that dissolves 10 g or more of water per 100 g at room temperature and normal pressure. A plurality of organic solvents other than water may be mixed and used as the solvent, and in this case, the mixture of the organic solvents may satisfy the above requirements.

Examples of the organic solvent include alcohols such as methanol, ethanol, isopropyl alcohol and butanol; ethers such as diethyl ether, tetrahydrofuran and dioxane; and amide compounds such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone.

Alcohols are by-produced during the reaction of the sol-gel method. Therefore, using alcohols such as methanol, ethanol, isopropyl alcohol or butanol among the above causes unnecessary impurities to be mixed into the dispersion after the reaction. It is particularly preferable because it can be suppressed and easily removed by heating.

The solvent can be used alone or as a mixture of two or more kinds of solvents.

The ratio of the solvent used may be appropriately determined according to the desired values of the particle size and concentration of the target silica particles. For example, when alcohol is used as the organic solvent, the proportion of alcohol in the mass (100% by mass) of the dispersion of silica particles obtained by the reaction of the sol-gel method is preferably 10 to 90% by mass, more preferably 15 to 80% by mass. Used to be in the% range.

Water may be used as a part or all of the solvent, or may be added to the reaction solution after all the reaction raw materials other than water have been prepared. However, in order to allow the reaction of the sol-gel method to proceed quickly and stably, it is preferable to use water as a part of the solvent, that is, to use a mixture of water and an organic solvent as the solvent. Here, water as a solvent is a concept including a case where it is added with the addition of a basic catalyst or the like.

The proportion of water used is appropriately adjusted and selected according to the particle size of the silica particles to be produced. If the water usage ratio is too small, the reaction rate will be slow, and if it is too large, it will take a long time to dry (solvent removal). Therefore, the water usage ratio is selected in consideration of both of these requirements. The proportion of water used is preferably in the range of 2 to 50% by mass and preferably in the range of 5 to 40% by mass with respect to the total mass of the dispersion of silica particles obtained by the reaction of the sol-gel method. More preferred.

(Basic catalyst)
A basic catalyst may be added to the fumed silica dispersion. By using a basic catalyst, the hydrolysis reaction and / or condensation reaction of alkoxysilane can be promoted. As the basic catalyst, any known basic catalyst used for producing inorganic oxide particles by the reaction of the sol-gel method can be preferably used. Examples of such a basic catalyst include amine compounds and alkali metal hydroxides. In particular, it is preferable to use an amine compound from the viewpoint that the amount of impurities is small and high-purity silica particles can be obtained. Examples of such amine compounds include ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, dimethylamine, trimethylamine and the like. Of these, ammonia is particularly preferable because it is highly volatile and easy to remove, and the reaction rate of the sol-gel method is high. The basic catalyst may be used alone or in combination of two or more.

As the basic catalyst, an industrially available one can be used as it is (in a commercially available form), or diluted with water or an organic solvent such as aqueous ammonia. It is also possible to use it. In particular, it is preferable to dilute the basic catalyst with water and use it as an aqueous solution whose concentration is adjusted as necessary because it is easy to control the progress rate of the reaction. When an aqueous solution of a basic catalyst is used, it is preferable to use an aqueous solution having a concentration in the range of 1 to 30% by mass because it is industrially easily available and the concentration can be easily adjusted.

The amount of the basic catalyst added may be appropriately determined in consideration of the reaction rate of the hydrolysis of alkoxysilane and the polycondensation reaction. As for the amount of the basic catalyst added, the amount of the basic catalyst present in the reaction solution is preferably 0.1 to 60% by mass with respect to the mass of the alkoxysilane used, and is 0.5 to 40% by mass. It is more preferable to use it in the range of%.

(Alkoxysilane)
Examples of the alkoxysilane include methyltrimethoxysilane, methyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane and tetrabutoxysilane. From the viewpoint of being easily available industrially and being easy to handle, the alkoxysilane is preferably methyltrimethoxysilane, tetramethoxysilane or tetraethoxysilane, and tetramethoxysilane or tetra. More preferably, it is ethoxysilane. As the alkoxysilane, only one type may be used, or two or more types may be used in combination. Further, in this step, a hydrolyzate of alkoxysilane may be added, or an alkoxysilane or a partial condensate of the hydrolyzate thereof may be added.

(Reaction conditions)
This step can be performed, for example, as follows. Examples thereof include a method in which fumed silica, a solvent and a basic catalyst are charged in a reaction vessel, and an alkoxysilane (or an organic solvent solution of the alkoxysilane) and an aqueous solution of the basic catalyst are simultaneously added thereto. According to this method, silica particles having good reaction efficiency and a narrow particle size distribution can be produced efficiently and with good reproducibility, which is preferable. When two or more kinds of alkoxysilanes are used in combination, they may be mixed and added at the same time, or each may be added sequentially.

The addition of the alkoxysilane and the basic catalyst is preferably added dropwise to the reaction solution. Here, in-liquid dropping means that when the alkoxysilane and the basic catalyst are dropped into the reaction solution, the tip of the dropping port is immersed in the reaction solution. The position of the tip of the dropping port is not particularly limited as long as it is in the liquid, but it may be a position where the dropping material can be rapidly diffused into the reaction liquid after sufficient stirring such as in the vicinity of the stirring blade. desirable.

The addition time of the alkoxysilane and the basic catalyst (time from the start of addition to the end of addition) is preferably 48 hours or less, for example. For example, if the addition time is 0.2 hours or more, the width of the particle size distribution can be reduced. Further, if the addition time is 48 hours or less, stable grain growth can be performed.

The reaction temperature is not particularly limited as long as the reaction of the sol-gel method proceeds rapidly, and may be appropriately selected according to the particle size of the target silica particles. Generally, the lower the reaction temperature, the larger the particle size of the obtained silica particles tends to be. For example, the reaction temperature may be appropriately selected in the range of −10 to 60 ° C.

In order to ensure that the reaction of the sol-gel method proceeds, aging (waiting for a while until the next addition of the hydrophobizing agent) may be carried out after the dropping of the alkoxysilane and the basic catalyst is completed. In this case, the aging temperature is preferably a temperature similar to the reaction temperature, that is, −10 to 60 ° C. The aging time is preferably 0.25 to 5 hours.

<2-2. Coagulation of silica particles>
This manufacturing method is described in <2-1. The step of adding a coagulant to the reaction solution in which the deformed silica particles obtained by the step of producing silica particles> described above is suspended may be included. By adding the coagulant to the reaction solution, agglomerates (cakes) in which silica particles are aggregated with a weak force are formed in the reaction solution. Due to the presence of the coagulant or a derivative thereof, such aggregates can be stably present in the reaction solution, and the formation of strongly aggregated aggregates can be prevented. In this step, the silica particles can be easily recovered by filtration by forming them into aggregates.

Examples of the coagulant include carbon dioxide, ammonium carbonate, ammonium hydrogencarbonate and ammonium carbamate. These coagulants are preferable because there is no possibility of mixing metal impurities as compared with the case where a metal salt is used as the coagulant. Further, since the coagulant is easily decomposed and removed by a slight heating, a high-purity deformed silica powder can be easily produced.

As the coagulant, at least one selected from the group consisting of ammonium hydrogen carbonate and ammonium carbamate is preferably used, ammonium hydrogen carbonate is more preferably used, and ammonium hydrogen carbonate is added as an aqueous solution. Is even more preferable. As the above-mentioned coagulant, only one kind may be used, or two or more kinds may be used in combination.

The amount of coagulant added and the method of addition can be set as follows according to the type of coagulant used. The amount of the coagulant added is set in consideration of the balance between the degree of formation of weak aggregates of silica particles in the reaction solution and the waste of using an unreasonably large amount of raw materials. The mass of the silica particles as a reference for the amount of the coagulant added below is a conversion value assuming that all the alkoxysilanes used are hydrolyzed and polycondensed.

When carbon dioxide is used as the coagulant, the amount of carbon dioxide added is preferably 15 parts by mass or more, preferably 15 to 300 parts by mass, based on 100 parts by mass of the silica particles contained in the reaction solution. More preferably, it is more preferably 17 to 200 parts by mass.

Examples of the method for adding carbon dioxide include a method of blowing carbon dioxide into the reaction solution in a gaseous state and a method of adding carbon dioxide in a solid state (dry ice). From the viewpoint of simplicity of operation, it is preferable to add carbon dioxide in a solid state.

When ammonium carbonate, ammonium hydrogencarbonate or ammonium carbamate is used as the coagulant, the amount added is preferably 15 parts by mass or more with respect to 100 parts by mass of the silica particles contained in the reaction solution. It is more preferably 15 to 80 parts by mass, further preferably 17 to 60 parts by mass, and particularly preferably 20 to 50 parts by mass.

Ammonium carbonate, ammonium hydrogencarbonate or ammonium carbamate may be added in a solid state or may be added in a solution state dissolved in a suitable solvent. The solvent used when these are added in a solution state is not particularly limited as long as they dissolve them, but water is used from the viewpoint of high dissolving ability and easy removal after filtration. It is preferable to use it. The concentration of the ammonium carbonate, ammonium hydrogen carbonate or ammonium carbamate solution is not particularly limited as long as they are dissolved, but is preferably 2 to 15% by mass, more preferably 5 to 12% by mass. At the above concentration, the amount of the solution used is not too large and it is economical.

In particular, a mixture of ammonium hydrogen carbonate and ammonium carbamate, which is commercially available as so-called "ammonium carbonate", can be used as it is or as a solution dissolved in a suitable solvent. In this case, the total amount of ammonium hydrogen carbonate and ammonium carbamate added, the type of solvent used when this is added as a solution, and the concentration of the solution are those of ammonium carbonate, ammonium hydrogen carbonate, or ammonium carbamate. In some cases, it is the same as described above.

In this step, the temperature at which the coagulant is added to the reaction solution of the silica particles is not particularly limited as long as the generated silica particles can stably agglomerate with a weak force. Just set it. Considering the decomposition temperature of the coagulant and the like, the temperature is usually the same as the reaction temperature of −10 to 60 ° C., preferably 10 to 40 ° C.

After the addition of the coagulant, it is preferable to carry out aging (that is, to allow some time before filtration in the next step). Aging after the addition of the coagulant promotes the formation of weak aggregates of the silica particles described above, which is preferable. The aging time is preferably 0.5 to 72 hours, more preferably 1 to 48 hours. When the aging time is 0.5 hours or more, the formation of aggregates can be sufficiently promoted. Further, if the aging time is 72 hours or less, it is economical. The temperature of the reaction solution during aging is not particularly limited, and the temperature range can be the same as the temperature at which the coagulant is added.

<2-3. Recovery of silica particles>
This manufacturing method is described in <2-1. Steps for producing silica particles> ~ <2-2. Includes a step of recovering the silica particles from the reaction solution containing the silica particles obtained by the step described in> Coagulation of Silica Particles>. The recovery method is not particularly limited, and examples thereof include a method of filtering and volatilizing the dispersion medium, and a method of decanting after the silica particles are precipitated by a centrifuge. Of these, filtration is preferable because silica particles can be easily recovered.

The filtration method is not particularly limited, and known methods such as vacuum filtration, pressure filtration and centrifugal filtration can be applied.

The filter paper, filter, filter cloth, etc. (hereinafter, collectively referred to as "filter paper, etc.") used for filtration can be used without particular limitation as long as they are industrially available, and are separation devices. It may be appropriately selected according to the scale of the (filter). Since the silica particles to be recovered in this production method are secondary particles, the pore size of the filter paper or the like may be much larger than the primary particle size. Therefore, it is possible to filter quickly.

Silica particles are recovered as cake by filtration. By rinsing the obtained cake with an appropriate solvent (for example, water or alcohol), the solvent used in the reaction by the sol-gel method and the basic catalyst can be decomposed and removed.
If there is a risk that the coagulant or its derivative may disappear due to the rinsing, the coagulant may be appropriately added so that the coagulant or its derivative in the cake does not disappear.

As a method for recovering silica, even when there is a risk that the coagulant or a derivative thereof may disappear at the time of recovery, such as a method of volatilizing a dispersion medium, the above-mentioned agglomerates (cake) of the silica particle reaction liquid at the time of recovery A coagulant may be added as appropriate so that the coagulant or a derivative thereof does not disappear in the agglomerate (cake).
<2-4. Drying of silica particles>
This manufacturing method is described in <2-3. Recovery of Silica Particles> may include a step of drying the silica particles obtained from the steps described above. As the drying method, a known method is not particularly limited and is adopted. For example, a drying method such as vacuum drying in a heated state and blast drying can be mentioned.

The temperature at the time of drying may be a temperature at which the dispersion medium can be removed and the salt derived from the coagulant can be decomposed, and may be appropriately determined in consideration of the pressure at the time of drying and the like. Specifically, the drying temperature is 35 to 250 ° C., more preferably 50 to 250 ° C.

In the present invention, when recovering and drying the silica particles from the reaction solution containing the silica particles, it is also possible to continuously remove the dispersion medium by concentration and drying. For example, the reaction solution containing silica particles is concentrated by heating, or the dispersion medium is volatilized by concentration under reduced pressure, so that the silica particles from which the dispersion medium is removed can be directly obtained from the reaction solution containing silica particles. Can be done. In this case, when the dispersion medium is removed by heating, the coagulant or its derivative may disappear. In such a case, an agglomerate (cake) of a reaction solution containing silica particles during concentration and drying. The coagulant may be appropriately added to the mixture so that the coagulant or a derivative thereof does not disappear in the agglomerate (cake).
<2-5. Firing of silica particles>
In general, silica obtained by the sol-gel method has a large amount of silanol groups on the surface of the silica, so that the saturated water content is about 8% by mass. The production method of the present invention includes a step of calcining the silica particles recovered from the reaction solution for the purpose of reducing the saturated water content.

The firing temperature is preferably 300 to 1300 ° C, more preferably 600 to 1200 ° C. If it is too low, the dehydration condensation reaction of silanol groups does not proceed, so that the saturated water content cannot be sufficiently reduced, and if it is too high, the silica particles are fused to each other.

The firing time is not particularly limited as long as it reaches the target saturated water content, but if it is too long, it is uneconomical. Therefore, after raising the temperature to the target firing temperature, 0.5 to 48 hours, more preferably. It is sufficient to hold and bake in the range of 2 to 24 hours.

The atmosphere at the time of firing is not particularly limited, and the firing can be performed under an inert gas such as argon or nitrogen, or under an atmospheric atmosphere. The deformed silica powder obtained after the firing treatment has high purity and a reduced saturated water content, and is therefore suitable as a filler for a sealing material.
<2-6. Crushing of silica particles>
The production method of the present invention includes a step of crushing silica particles obtained by a firing step. Since the silica particles obtained after the firing treatment contain agglomerated particles, they are crushed by a known crushing means such as a jet mill before use.

Conditions for crushing using a jet mill is not particularly limited, air as a compressed gas, or an inert gas such as N _2, the powder concentration in the gas is 10 g / m ³ or more 220 g / m It is preferably carried out so as to be ³ or less, preferably 15 g / m ³ or more and 190 g / m ³ or less, and more preferably 15 g / m ³ or more and 30 g / m ³ or less. The higher the powder concentration, the better the crushing ability. However, even if the powder concentration is too high, the crushing force applied to each particle is dispersed and the crushing efficiency is lowered, so that the powder concentration is within the above range. Is preferable. When it is difficult to obtain the above powder concentration, it may be crushed once and then repeatedly crushed until the desired powder physical properties are obtained. Of course, the above-mentioned jet mill crushing is an example, and other known crushing, crushing, classifying and the like devices may be appropriately selected.

The silica powder obtained by crushing can further remove coarse particles and the like using a sieve or the like. The silica powder from which the coarse particles have been removed is suitably used as a filler for a sealing material for semiconductor devices, which has a narrower gap and higher integration.

<2-7. Surface treatment>
This manufacturing method is described in <2-6. Crushing of silica particles> For the silica particles obtained from the process described above, use a known surface treatment agent such as silicone oil, a silane coupling agent, silane coupling agent, titanate-based coupling agent, and aluminum-based coupling agent. It is also possible to perform surface treatment and use it for the desired purpose. Among these, it is particularly preferable to use silicone oil, a silane coupling agent, and silazane.

As the silicone oil used in the present invention, a known silicone oil usually used for surface treatment can be used without particular limitation, and it is appropriately selected according to the required performance of the surface-treated silica particles and the like. You can use it. Specifically, dimethyl silicone oil, methylphenyl silicone oil, methylhydrogen silicone oil, alkyl-modified silicone oil, amino-modified silicone oil, epoxy-modified silicone oil, carboxyl-modified silicone oil, carbinol-modified silicone oil, and methacryl-modified Examples thereof include silicone oil, polyether-modified silicone oil, and fluorine-modified silicone oil. Among these, it is preferable to use dimethyl silicone oil if the purpose is simply to hydrophobize.

The amount of silicone oil used is not particularly limited, but if it is too small, the surface treatment will be insufficient, and if it is too large, the post-treatment will be complicated. Therefore, 0.05 based on 100 parts by mass of the silica particles used. It is preferably ~ 30 parts by mass, more preferably 0.1 to 20 parts by mass.

As the silane coupling agent used in the present invention, a known silane coupling agent usually used for surface treatment can be used without particular limitation, and it is appropriate depending on the required performance of the surface-treated silica particles and the like. You can select it and use it. Specifically, methyltrimethoxysilane, methyltriethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane. , 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxymethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-gly Sidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-acryloxypropyltrimethoxy Silane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane , N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N, N-dimethyl-3-aminopropyltrimethoxysilane, N, N-diethyl- Examples thereof include 3-aminopropyltrimethoxysilane, 4-styryltrimethoxysilane, phenyltrimethoxysilane, and phenyltriethoxysilane.
Among these, from the viewpoint of dispersibility with the resin to be filled, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-acryloxipropyl It is preferable to use trimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-methacryloxypropylmethyldimethoxysilane.
Further, if the purpose is simply to carry out hydrophobicization, it is preferable to use methyltrimethoxysilane, methyltriethoxysilane, hexyltrimethoxysilane, and decyltrimethoxysilane.

The amount used when using the silane coupling agent is not particularly limited, but if it is too small, the surface treatment becomes insufficient, and if it is too large, the post-treatment becomes complicated. Therefore, with respect to 100 parts by mass of the silica particles used. It is preferably 0.05 to 40 parts by mass, more preferably 0.1 to 30 parts by mass.

As the silazane used in the present invention, known silazane usually used for surface treatment can be used without particular limitation. Among the silazanes, hexamethylsilazane is preferably used because of its good reactivity and handling.

The amount of silazane to be used is not particularly limited, but if it is too small, the surface treatment becomes insufficient, and if it is too large, the post-treatment becomes complicated. Therefore, 0.05 is applied to 100 parts by mass of the silica particles to be used. It is preferably ~ 60 parts by mass, more preferably 0.1 to 50 parts by mass.

Only one type of these surface treatment agents may be used alone, or two or more types may be used in combination. It is also possible to perform processing in multiple stages.

[3. Resin composition]
The present invention also provides a resin composition containing the above-mentioned modified silica powder. The type of resin is not particularly limited, and examples thereof include epoxy resin, acrylic resin, silicone resin, polyester resin, urethane resin, and olefin resin. Among them, epoxy resin is preferably used as an adhesive / sealing resin.

In the resin composition of the present invention, when the semiconductor encapsulant is used, the deformed silica particles used as the filler do not have a crushed surface, which may cause damage to the surface of the semiconductor element or the wire or wear of the mold. In addition, since the viscosity at the time of dispersion is low and the fluidity is excellent as compared with the case where crushed silica is used, the filling rate can be maintained high and the solder reflow resistance is excellent.

On the other hand, since the silica particles used as the filler have irregularities, the contact points between the particles or the adhesive member increase as compared with the conventional spherical silica, so that the resin after molding has stable bending strength and adhesive strength. Can be obtained.

In addition, the above-mentioned irregularly shaped silica powder is used as an anti-blocking agent and dispersed in an olefin resin or the like to be suitably used as a resin composition for a film. In the resin composition, the deformed silica powder does not have a crushed surface, so that it has excellent dispersibility, and because it has irregularities, it has excellent adhesiveness to the resin and does not easily fall off.

The method for producing the resin composition is not particularly limited as long as it uses the deformed silica powder of the present invention as the filler, and a known method for producing the resin composition is preferably used. As an additive to the above resin, not only the modified silica powder of the present invention but also an existing silica powder may be used in combination.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to the following Examples. In addition, various physical property measurements and the like in the following examples are carried out by the following methods.

[Measurement method of physical properties]
(1) Median diameter and maximum (peak) of weight-based particle size distribution, and geometric standard deviation σg
(Preparation of measurement sample)
A 2-propanol suspension having a concentration of silica as a measurement sample of 1.5% by mass was prepared as follows. 0.3 g of silica powder and 20 g of 2-propanol were placed in a glass sample tube bottle (manufactured by AS ONE Corporation, content 30 mL, outer diameter about 28 mm). The sample tube bottle containing the sample was placed so that the probe tip surface of the ultrasonic cell crusher (manufactured by BRANSON, model number Sonifier II Model 250D, probe: 1/4 inch) was 15 mm below the water surface. Using the ultrasonic cell crusher, silica powder was dispersed in 2-propanol under the conditions of an output of 20 W and a dispersion time of 45 minutes, and 2-propanol suspension in which the concentration of silica as a measurement sample was 1.5% by mass. The liquid was prepared.

(Measuring method)
The median diameter and particle size distribution were measured using a disk centrifugal sedimentation type particle size distribution measuring device (manufactured by CPS, model number DC-24000). The measurement conditions were a rotation speed of 18,000 rpm, a silica true density of 2.1 g / cm ³ , and calibrated for each measurement with 0.476 μm PVC particles. The geometric standard deviation σg of the particle size distribution was calculated from the obtained weight-based particle size distribution obtained by logarithmic mean distribution fitting (least squares method) in the range of cumulative frequency of 10% by mass to 90% by mass.

(2) The ratio (S / S ₀ ) of the area (S) obtained by the image analysis method to the entanglement area (S ₀ ) obtained by the image analysis method, the average circularity of the particles, and the circularity are 0.95. Particle content (measurement method)
A bright-field-scanning transmission image (BF-STEM) was taken of 500 or more silica particles using FE-SEM (manufactured by Hitachi High-Technologies Corporation, model number S-5500) at an accelerating voltage of 30 kV and a magnification of 20000 times. .. The photograph taken was taken into the image analysis software "A image-kun" (manufactured by Asahi Kasei Engineering Co., Ltd.), and the particle analysis parameters were set as follows, and the particles were analyzed.
Particle brightness: Dark binarization method: Manual shrinkage Separation count: 20 times Small figure: 0
Noise reduction filter: Yes Shading: Yes Result display unit: nm
By particle analysis, the area (S), the envelopment area (S ₀ ) (the area surrounded by the envelope connecting the convex parts of the particles) and the aspect ratio of each particle were determined. Furthermore, the ratio (S / S ₀ ) of the area of each particle to the enveloping area was determined. Further, the circularity of each particle was calculated by the following formula (1) using the area and the peripheral length of each particle.

Circularity = 4π x area / (peripheral length) ² (1)
The ratio of area to entanglement area (S / S ₀ ), average circularity and aspect ratio are the ratio of the area of each particle to the entanglement area (S / S ₀ ), circularity and aspect ratio obtained by the above image analysis. The ratio was averaged and calculated. In addition, the number ratio of particles having a ratio (S / S ₀ ) of area to envelopment area (S / S ₀ ) of 0.97 or more and the number ratio of particles having a circularity of 0.95 or more were determined.

(3) Saturated water content The saturated water content was measured by the following method. 10 g of silica powder was dried at 120 ° C. for 24 hours, and then cooled in a desiccator containing silica gel. Subsequently, the particles cooled in the desiccator were allowed to stand in an environment of 25 ° C. and 50% RH for 48 hours, and the mass (Dwet) of the particles was weighed. The weighed particles were dried again at 120 ° C. for 24 hours and the mass of the particles (Ddry) was weighed. From the mass change before and after humidity control, the value calculated by the following mathematical formula (2) was defined as the saturated water content.

Saturated water content (mass%) = ((Dwet-Ddry) / Ddry) × 100 Formula (2)
(4) Degree of hydrophobization (M value)
After weighing 50 mL of water in a beaker having a capacity of 200 mL, 0.2 g of a silica powder sample was put into the beaker. While stirring this with a magnetic stirrer, methanol was added dropwise with a burette, and titration was carried out starting from the point where the entire amount of the added silica powder was wetted with the solvent in the beaker and suspended. At this time, the silica powder sample was introduced into the solvent with a tube so that the methanol would not come into direct contact with the sample. Then, the value of the volume% of methanol in the methanol-water mixed solvent at the end point of the titration was defined as the degree of hydrophobicity (M value).

(5) True specific gravity Measured using a dry automatic densitometer (manufactured by Shimadzu Corporation, model number Accupic II 1340 series) using a 10 cc cell.

(6) Sodium, potassium and iron content <Sodium and potassium content>
(Preparation of measurement sample)
5 g of silica powder was added to 50 g of ultrapure water, and the mixture was heated at 120 ° C. for 24 hours using a Teflon (registered trademark) decomposition vessel. Ultrapure water and silica powder were weighed to 0.1 mg units. Then, the silica solid content was separated using a centrifuge to obtain an ion chromatograph measurement sample. The above operation was performed using only ultrapure water to obtain a blank sample.

(Measurement)
The concentrations of sodium and potassium in the measurement sample were measured using an ion chromatography system (manufactured by Nippon Dionex Corporation, model number ICS-2100). The sodium and potassium contents of the silica powder were calculated using the following formula (3).

C _Silicona = (C _Sample- C _Blank ) x _MPW / M _Silicona (3)
C _Silica : Ion concentration in silica (ppm)
C _Sample : Ion concentration (ppm) in the measurement sample
C _Blank : Ion concentration in blank sample (ppm)
_MPW : Ultrapure water amount (g)
M _Silica : Silica weight (g)
The C _Blank of each ion was 0 ppm.

<Iron content>
2 g of the dried silica powder was precisely weighed and transferred to a platinum dish, and 10 mL of concentrated nitric acid and 10 mL of hydrofluoric acid were added in this order. This was placed on a hot plate set at 200 ° C. and heated to dry the contents. After cooling to room temperature, 2 mL of concentrated nitric acid was further added, and the mixture was placed on a hot plate set at 200 ° C. and heated to dissolve. After cooling to room temperature, the solution contained in the platinum dish was transferred to a volumetric flask having a capacity of 50 mL, diluted with ultrapure water, and aligned with the marked line. Using this as a sample, the iron content was measured by an ICP emission spectrometer (manufactured by Shimadzu Corporation, model number ICPS-1000IV).

(7) Dispersibility index of fumed silica dispersion Put the dispersion consisting of fumed silica and methanol into a measurement sample cell (synthetic cell manufactured by Tokyo Glass Instruments Co., Ltd., 5-sided transparent, 10 × 10 × 45H). , The absorbances τ ₇₀₀ and τ ₄₆₀ of the dispersion were determined using a spectrophotometer (manufactured by JASCO Corporation, model number V-630). The dispersibility index n of the dispersion was calculated using the following formula (4).

n = 2.382 × ln (τ ₄₆₀ / τ ₇₀₀ ) (4)
Note that τ ₇₀₀ represents the absorbance of the dispersion with respect to light having a wavelength of 700 nm, and τ ₄₆₀ represents the absorbance of the dispersion with light having a wavelength of 460 nm.

When the value of the obtained dispersibility index was 2.5 or more, it was judged that the fumed silica was sufficiently dispersed in the dispersion liquid without agglutination.

(8) Viscosity The viscosity evaluation when the silica powder was filled in the polar resin was evaluated by filling the epoxy resin. 20 g of silica powder was added to 25 g of a bisphenol A + F type mixed epoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., ZX-1059) and kneaded by hand. For untreated silica powder that has not undergone any surface treatment including only hydrophobization treatment, 0.25 g of 3-glycidoxypropyltrimethoxysilane (manufactured by Shinetsu Silicone, KBM-403) is further added by hand. I kneaded it. Each hand-kneaded resin composition was pre-kneaded with a rotating and revolving mixer (manufactured by THINKY, Awatori Rentaro AR-500) (kneading: 1000 rpm, 8 minutes, defoaming: 2000 rpm, 2 minutes). The pre-kneaded resin composition was kneaded using three rolls (BR-150HCV roll diameter φ63.5, manufactured by IMEX). The kneading conditions were such that the kneading temperature was room temperature, the distance between rolls was 20 μm, and the number of kneading was 5 times.

The viscosity of the kneaded resin composition was measured at a shear rate of 1s-1 with a rheometer (ReoStress, manufactured by HAAKE).

(9) Adhesive strength 1 g of O-Cresol novolak epoxy resin (EOCN-1020-75 manufactured by Nippon Kayaku) and 1 g of pentaerythritol triacrylate (Viscoat # 300 manufactured by Osaka Organic Chemical Industry Co., Ltd.) are placed in an alumina dairy pot and heated to 120 ° C. The mixture was heated and reacted to obtain a uniform epoxy acrylate solution. 0.5 g of silica powder was added to the above solution, and the mixture was well rubbed in a mortar and dispersed uniformly. For untreated silica powder that has not been surface-treated, including only hydrophobization, 0.005 g of 3-glycidoxypropyltrimethoxysilane is further added, and the mixture is well rubbed in a mortar and dispersed uniformly. It was. After uniform dispersion, 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin (Ajinomoto Fine-Techno, Amicure VDH), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl), respectively. -Butanone-1 (manufactured by Ciba Japan, Irgacure 369) and N, N'-tetraethyldiaminobenzophenone were added at once and mixed well. Finally, 2-phenyl-4-methylimidazole (Shikoku Chemicals, Curesol 2P4MZ) was added and further mixed.

The resin composition obtained by mixing was placed in a UV syringe and kneaded and defoamed with a rotating and revolving mixer (manufactured by THINKY, Awatori Kentarou ARE-250) (kneading: 2000 rpm, 2 minutes, defoaming). : 2200 rpm, 5 minutes).

Next, a certain amount of the resin composition is applied onto the glass using a dispenser (ML-5000XII manufactured by Musashi Engineering Co., Ltd.), and a pair of similar glasses are laminated in a cross shape from above to apply a load. While applying an ultraviolet irradiation device (365 nm, 5 minutes), photocuring was performed.
After curing, a wire was attached to the cross glass sample, pulled from above and below, and the adhesive strength was measured using a tensile / compression tester (EZ-test manufactured by Shimadzu Corporation) (see FIG. 6).

[Example 1]
Fumed silica (manufactured by Tokuyama Co., Ltd., trade name QS-30, BET specific surface area 302 m ² / g, average primary particle diameter 7 nm) 5.25 g and methanol 520 g in a ² L capacity disposable cup (manufactured by AS ONE Corporation) I put it in. The disposable cup containing the sample was placed so that the probe tip surface of the ultrasonic cell crusher (Soniffier II Model 250D manufactured by BRANSON, probe: 1/4 inch) was 10 mm from the bottom of the disposable cup. Using the ultrasonic cell crusher, fumed silica was dispersed in methanol under the conditions of an output of 60 W and a dispersion time of 30 minutes to prepare a dispersion. This operation was carried out twice to mix the prepared dispersions to obtain a dispersion consisting of 10.5 g of fumed silica and 1040 g of methanol. The dispersibility index of the dispersion was 2.82, confirming that fumed silica was sufficiently dispersed.

Subsequently, 1050.5 g of the prepared dispersion and 152 g of 15 mass% ammonia water as the charged ammonia water were put into a 5 L four-necked flask, and the mixture was stirred at 35 ° C. 705.5 g of tetramethoxysilane as an alkoxysilane and 232.2 g of 5 mass% ammonia water as added ammonia water were independently added dropwise in the liquid. The dropping was carried out by adjusting the speed so that the dropping was completed in 120 minutes. The reaction solution became cloudy 10 minutes after the start of dropping, and it was confirmed that the reaction was proceeding.

After completion of the dropping, the mixture was aged for 30 minutes, 1000 g of a 10% aqueous ammonium hydrogen carbonate solution was added, and the mixture was stirred for 120 minutes. After 120 minutes, a quantitative filter paper (holding particle size 7 μm) was used and vacuum filtration was performed to obtain a cake. The filtrate was transparent and no filtration leakage was confirmed. Further, it was dried under reduced pressure at 100 ° C. for 16 hours to obtain 272 g of silica powder.

Subsequently, the obtained silica powder was fired at 900 ° C. for 10 hours in a firing furnace. The firing atmosphere was not particularly adjusted, and was carried out in an air atmosphere. The obtained silica powder after firing was used on a jet mill (PJM-100SP manufactured by Nippon Pneumatic Industries Co., Ltd.), and both the feed pressure and the mill pressure were 0.60 MPa and 1.9 Nm ³ / min compressed air. , the supply amount of the drug substance is pulverized in a 36.7kg / min, the unit airflow per 20 g / ^{m 3,} to obtain a variant silica powder 210g. The obtained irregularly shaped silica powder had a median diameter of 293 nm and an unevenness of 0.81. The viscosity of the resin composition was 80 Pa · s, and the adhesive strength after curing was 24 N.

[Example 2]
A modified silica powder was obtained in the same manner as in Example 1 except that the amount of tetramethoxysilane added was changed to 680 g. The obtained irregularly shaped silica powder had a median diameter of 262 nm and an unevenness of 0.82. The viscosity of the resin composition was 101 Pa · s, and the adhesive strength after curing was 24 N.

[Example 3]
The amount of tetramethoxysilane added was changed to 352.8 g, the amount of 5% by mass ammonia water added as added ammonia water was changed to 116.1 g, and the dropping time (supply time) of these was changed to 60 minutes. A modified silica powder was obtained in the same manner as in Example 1 except for the above. The obtained irregularly shaped silica powder had a median diameter of 179 nm and an unevenness of 0.77. The viscosity of the resin composition was 212 Pa · s, and the adhesive strength after curing was 27 N.

[Example 4]
A modified silica powder was obtained in the same manner as in Example 3 except that the temperature at which the prepared dispersion liquid and the charged aqueous ammonia were stirred in a four-necked flask was changed to 40 ° C. The obtained irregularly shaped silica powder had a median diameter of 196 nm and an unevenness of 0.75. The viscosity of the resin composition was 176 Pa · s, and the adhesive strength after curing was 29 N.

[Example 5]
The amount of tetramethoxysilane added was changed to 493.9 g, the amount of 5% by mass ammonia water added as added ammonia water was changed to 162.5 g, and the dropping time (supply time) of these was changed to 84 minutes. A modified silica powder was obtained in the same manner as in Example 1 except for the above. The obtained deformed silica powder had a median diameter of 210 nm and an unevenness of 0.79. The viscosity of the resin composition was 139 Pa · s, and the adhesive strength after curing was 24 N.

[Example 6]
A modified silica powder was obtained in the same manner as in Example 1 except that the dropping time (supply time) of the alkoxysilane and the added ammonia water was changed to 240 minutes. The obtained deformed silica powder had a median diameter of 295 nm and an unevenness of 0.81. The viscosity of the resin composition was 82 Pa · s, and the adhesive strength after curing was 24 N.

[Example 7]
The amount of tetramethoxysilane added was changed to 220.5 g, the amount of 5% by mass ammonia water added as added ammonia water was changed to 72.6 g, and the dropping time (supply time) of these was changed to 60 minutes. A silica powder was obtained in the same manner as in Example 1 except for the above. The obtained irregularly shaped silica powder had a median diameter of 130 nm and an unevenness of 0.69. The viscosity of the resin composition was 330 Pa · s, and the adhesive strength after curing was 28 N.

[Example 8]
Deformed silica in the same manner as in Example 1 except that tetraethoxysilane was added as the alkoxysilane instead of tetramethoxysilane, and the dropping time (supply time) of the alkoxysilane and the added ammonia water was changed to 180 minutes. Obtained powder. The obtained irregularly shaped silica powder had a median diameter of 301 nm and an unevenness of 0.83. The viscosity of the resin composition was 73 Pa · s, and the adhesive strength after curing was 24 N.

[Example 9]
The amount of fumed silica added was changed to 26.7 g, the amount of tetramethoxysilane added was changed to 1763.6 g, and the amount of 5% by mass ammonia water added as added ammonia water was changed to 580.5 g. A modified silica powder was obtained in the same manner as in Example 1 except that the dropping time (supply time) was changed to 300 minutes. The obtained irregularly shaped silica powder had a median diameter of 283 nm and an unevenness of 0.80. The viscosity of the resin composition was 90 Pa · s, and the adhesive strength after curing was 24 N.

[Example 10]
As the fumed silica, the trade name QS-102 (BET specific surface area 205 m ² / g, average primary particle diameter 12 nm) manufactured by Tokuyama Co., Ltd. was used instead of the trade name QS-30 manufactured by Tokuyama Co., Ltd. A modified silica powder was obtained in the same manner as in Example 1 except that the dropping time (supply time) of the alkoxysilane and the added ammonia water was changed to 180 minutes. The obtained irregularly shaped silica powder had a median diameter of 315 nm and an unevenness of 0.81. The viscosity of the resin composition was 84 Pa · s, and the adhesive strength after curing was 24 N.

[Example 11]
As the fumed silica, the trade name QS-09 (BET specific surface area 85 m ² / g, average primary particle diameter 22 nm) manufactured by Tokuyama Co., Ltd. was used instead of the trade name QS-30 manufactured by Tokuyama Co., Ltd. A modified silica powder was obtained in the same manner as in Example 1 except that the dropping time (supply time) of the alkoxysilane and the added ammonia water was changed to 240 minutes. The obtained irregularly shaped silica powder had a median diameter of 362 nm and an unevenness of 0.81. The viscosity of the resin composition was 69 Pa · s, and the adhesive strength after curing was 24 N.

[Example 12]
The amount of tetramethoxysilane added was changed to 1763.6 g, the amount of 5% by mass ammonia water added as added ammonia water was changed to 580.5 g, and the dropping time (supply time) of these was changed to 300 minutes. A silica powder was obtained in the same manner as in Example 1 except for the above. The obtained irregularly shaped silica powder had a median diameter of 410 nm and an unevenness of 0.87. The viscosity of the resin composition was 66 Pa · s, and the adhesive strength after curing was 29 N.

[Example 13]
Using the trade name QS-09 (BET specific surface area 85 m ² / g, average primary particle diameter 22 nm) manufactured by Tokuyama Co., Ltd. instead of the trade name QS-30 manufactured by Tokuyama Co., Ltd. as fumed silica, Tetra The amount of methoxysilane added was changed to 211.6 g, the amount of 5% by mass ammonia water added as added ammonia water was changed to 696.6 g, and the dropping time (supply time) of these was changed to 300 minutes. A silica powder was obtained in the same manner as in Example 1 except for the above. The obtained irregularly shaped silica powder had a median diameter of 462 nm and an unevenness of 0.89. The viscosity of the resin composition was 60 Pa · s, and the adhesive strength after curing was 32 N.

[Example 14]
A modified silica powder was obtained in the same manner as in Example 1 except that the concentration of the added ammonia water was changed to 2.6% by mass and the amount of the added ammonia water added was changed to 226.4 g. The obtained irregularly shaped silica powder had a median diameter of 262 nm and an unevenness of 0.81. The viscosity of the resin composition was 100 Pa · s, and the adhesive strength after curing was 24 N.

[Example 15]
A modified silica powder was obtained in the same manner as in Example 1 except that the concentration of the added ammonia water was changed to 9.5% by mass and the amount of the added ammonia water added was changed to 121.9 g. The obtained irregularly shaped silica powder had a median diameter of 292 nm and an unevenness of 0.81. The viscosity of the resin composition was 81 Pa · s, and the adhesive strength after curing was 24 N.

[Example 16]
400 g of the deformed silica powder obtained by the method of Example 1 was placed in a 20 L pressure vessel, and the temperature was raised to 230 ° C. After replacing the inside of the container with a nitrogen atmosphere, the container was sealed under atmospheric pressure, and 20 g of water was sprayed while stirring the particles. Then, after continuing stirring for 15 minutes, the pressure was depressurized and 120 g of hexamethyldisilazane was sprayed. Further stirring was continued for 1 hour, and then decompression was performed to obtain 350 g of hydrophobic irregularly shaped silica powder. The obtained irregularly shaped silica powder had a median diameter of 293 nm and an unevenness of 0.81. The viscosity of the resin composition was 39 Pa · s, and the adhesive strength after curing was 39 N.

[Example 17]
Hydrophobic variant silica powder in the same manner as in Example 15 except that water was not sprayed and the surface treatment agent to be added was changed from hexamethyldisilazane to 40 g of 3-glycidoxypropyltrimethoxysilane. Got The obtained irregularly shaped silica powder had a median diameter of 293 nm and an unevenness of 0.81. The viscosity of the resin composition was 34 Pa · s, and the adhesive strength after curing was 44 N.

[Example 18]
A hydrophobic variant silica powder whose surface was surface-treated in two steps was obtained in the same manner as in Example 16 except that the hydrophobic variant silica powder obtained by the method of Example 17 was used. The obtained irregularly shaped silica powder had a median diameter of 293 nm and an unevenness of 0.81. The viscosity of the resin composition was 28 Pa · s, and the adhesive strength after curing was 52 N.

[Comparative Example 1]
Silica powder was obtained in the same manner as in Example 1 except that fumed silica was not used. That is, as shown in FIG. 4A, after nucleation particles were generated by the nucleation reaction, the nuclei were grown into grains to obtain silica powder. The obtained silica powder was spherical silica having a median diameter of 79 nm and an unevenness of 1.00. The viscosity of the resin composition was 498 Pa · s, and the adhesive strength after curing was 13 N.

[Comparative Example 2]
The reaction temperature was changed to 25 ° C., the amount of tetramethoxysilane added was changed to 211.6 g, the amount of 5% by mass ammonia water added as the added ammonia water was changed to 696.5 g, and these were dropped. A silica powder was obtained in the same manner as in Comparative Example 1 except that the time (supply time) was changed to 380 minutes. The obtained silica powder was spherical silica having a median diameter of 285 nm and an unevenness of 1.00. The viscosity of the resin composition was 81 Pa · s, and the adhesive strength after curing was 18 N.

[Comparative Example 3]
Hydrophobic silica particles were obtained in the same manner as in Example 16 except that the silica particles obtained by the method of Comparative Example 2 were used. The obtained silica powder was spherical silica having a median diameter of 285 nm and an unevenness of 1.00. The viscosity of the resin composition was 35 Pa · s, and the adhesive strength after curing was 34 N.

〔result〕
From the results of the above Examples and Comparative Examples, the resin composition to which the modified silica powder of the present invention was added had the same viscosity and was cured as compared with the resin composition to which the spherical silica powder having the same particle size was added. A resin having a high adhesive strength was obtained later. Further, the amorphous silica powder having hydrophobicity also has the same particle size, and the viscosity of the resin composition is about the same as that of the one to which the similarly surface-treated spherical silica powder is added, and after curing. A resin having high adhesive strength was obtained.

The reaction conditions of Examples 1 to 18 and Comparative Examples 1 to 3 are shown in Table 1. Table 2 shows the measurement results of various physical properties in Examples 1 to 18 and Comparative Examples 1 to 3.

The present invention can be suitably used in the field of, for example, a filler for a semiconductor encapsulant.

1 Variant silica particles

Claims (9)

The median diameter of the weight-based particle size distribution measured by the centrifugal sedimentation method is in the range of 50 to 1000 nm.
The ratio (S / S ₀ ) of the area (S) obtained by the image analysis method to the envelope area (S ₀ ) obtained by the image analysis method is in the range of 0.60 to 0.95.
The maximum (peak) of the weight-based particle size distribution obtained by the centrifugal sedimentation method is one, and the geometric standard deviation σg is 1.5 or less.
Irregular silica powder saturated water content as determined by loss on drying method at 120 ° C. is Ri der than 1.5 wt%, and wherein the Rukoto which have a hydrophobic. The modified silica powder according to claim 1, wherein the average circularity of the particles obtained by the image analysis method is in the range of 0.40 to 0.85. The modified silica powder according to claim 1 or 2, wherein the content of particles having a circularity of 0.95 or more and 5% by number or less obtained by an image analysis method is used. The modified silica powder according to any one of claims 1 to 3, wherein the contents of sodium, potassium and iron are each less than 1 ppm. A resin composition containing the modified silica powder according to any one of claims 1 to 4. The median diameter of the weight-based particle size distribution measured by the centrifugal sedimentation method is in the range of 50 to 1000 nm.
Area (S) obtained by image analysis method and envelope area (S) obtained by image analysis method ₀ ) To ratio (S / S ₀ ) Is in the range of 0.60 to 0.95,
The maximum (peak) of the weight-based particle size distribution obtained by the centrifugal sedimentation method is one, and the geometric standard deviation σg is 1.5 or less.
A resin composition containing a deformed silica powder having a saturated water content of 1.5% by mass or less as measured by a drying weight loss method at 120 ° C. The resin composition according to claim 6, wherein the irregularly shaped silica powder has an average circularity of particles obtained by an image analysis method in the range of 0.40 to 0.85. The resin composition according to claim 6 or 7, wherein the deformed silica powder has a content of particles having a circularity of 0.95 or more and 5% by number or less obtained by an image analysis method. The resin composition according to any one of claims 6 to 8, wherein the variant silica powder has a sodium, potassium and iron content of less than 1 ppm each.

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