JP2016079061A - Inorganic filler and method for producing the same, resin composition and molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inorganic filler without almost containing coarse particles having a particle diameter of 5 μm or more.SOLUTION: It was found that aggregation during classification operations is suppressed by incorporating a fine particle material in a nanometer order having predetermined properties. That is, there is provided a mixture containing 100 pts.mass of inorganic particles having a volume average particle diameter of 0.1 to 3 μm and 0.01 to 10 pts.mass of a fine particle material having a particle diameter of 2 to 100 nm which has a hydrophobized surface, wherein after forming the inorganic particles, the mixture is produced without via a step for dispersing into the remaining liquid and the mass of the coarse particles having a particle diameter of 5 μm or more is less than 100 ppm based on the total mass.SELECTED DRAWING: None

Description

  The present invention relates to an inorganic filler with an extremely small amount of coarse particles, a method for producing the same, a resin composition containing the inorganic filler, and a molded product obtained by curing the resin composition.

  In order to improve physical properties, sealing materials for sealing electronic components such as semiconductor devices that make up electronic devices, substrates on which electronic components are arranged, and other precision components are made of inorganic materials. These members are made by adopting a resin composition in which an inorganic filler having excellent thermal and mechanical properties compared to resin materials is dispersed in the resin material, and molding and solidifying the resin composition into a molded product. May form.

  In recent years, electronic devices such as portable terminals have been increasing in density and accuracy year by year, and parts used for these devices are also required to have high density and accuracy. Therefore, depending on the size of the inorganic filler contained in the resin composition constituting the encapsulant or the substrate, the content of coarse particles that are particles having a particle size of a predetermined size or more because it greatly affects the performance of the molded product Restrictions have been made. A classifying operation is widely used as a method for limiting the content of coarse particles. For example, in Patent Document 1, coarse particles having a particle size of 50 μm or more are separated and removed by sieving performed by a dry method.

  By the way, in recent years, the content of coarse particles having a particle size of 5 μm or more is limited, but the classification operation in the vicinity of the particle size of 5 μm cannot be realized unless it is dispersed in a liquid. If they are not dispersed in the liquid, they will aggregate and the filter will not function. If a centrifugal classifier is used, classification operation is possible without being dispersed in a liquid, but aggregation still proceeds and precise classification cannot be realized. As a result, when the content of coarse particles was reduced to the utmost limit, the content of coarse particles contained in the inorganic filler could not be reduced to the target amount unless dispersed in a liquid.

JP 2004-269636 A

  However, when the classification operation is performed in the liquid to remove the coarse particles having a particle diameter of 5 μm or more, even if the coarse particles can be removed in the dispersed state, the liquid needs to be removed. As the drying proceeds, the particles aggregate to form secondary particles having a large particle size. Therefore, the content of coarse particles could not be reduced sufficiently.

  Furthermore, if classification operation is performed in a liquid, the liquid used for the inorganic filler will remain. If the liquid remains, there is a concern that a liquid which is not desirable to be dispersed when dispersed in the resin composition, or that the liquid mixed in the molded article causes an unexpected situation.

  The present invention has been completed in view of the above circumstances, and provides an inorganic filler in which no liquid remains, a method for producing the same, a resin composition containing the inorganic filler, and a molded product obtained by curing the resin composition. This is a problem to be solved.

(1) As a result of intensive studies aimed at solving the above problems, the present inventors have obtained the following knowledge. First, a method of adding a fine particle material having a particle size of 2 nm to 100 nm and having a hydrophobic surface as means for suppressing aggregation of particles made of an inorganic material constituting an inorganic filler having a particle size of 5 μm or less I found By mixing such fine particle materials at a predetermined ratio, aggregation of particles made of an inorganic material is effectively suppressed. Conventionally, even if coarse particles are removed by classification, agglomeration exceeding the size of the coarse particles has been generated by aggregation, but the addition of the fine particle material suppresses the formation of such aggregates. The present inventors have completed the present invention based on the above findings.

That is, the inorganic filler of the present invention that solves the above problems is 100 parts by mass of inorganic particles having a volume average particle size of 0.1 μm to 3 μm,
A mixture having 0.01 to 10 parts by mass of a fine particle material having a hydrophobic surface and a particle diameter of 2 to 100 nm,
After the inorganic particles are formed, the coarse particles having a particle diameter of 5 μm or more manufactured without the step of dispersing in the remaining liquid are less than 100 ppm based on the total mass.

  By including a fine particle material, it has become possible to sufficiently separate and remove coarse particles even if classification is performed by a dry method. In order to accurately separate and remove coarse particles as small as 5 μm, a large external force is required. For example, in centrifugal classification, a large centrifugal force is applied. In that case, the inorganic particles to be classified were subjected to a large external force, which caused adhesion and clogging of the inorganic particles to the classification equipment, resulting in turbulence and blockage of the air flow, and the coarse particles could not be removed effectively.

  In the present invention, by adding an appropriate amount of the appropriate fine particle material, even if a large force is applied, the fluidity of the inorganic particles is ensured so that the coarse particles can be accurately separated and removed without causing adhesion and clogging to the equipment. Therefore, it has become possible to provide an inorganic filler from which coarse particles have been removed in a dry state that could not be realized in the past.

  Here, “microparticle material” in this specification is named to distinguish it from inorganic particles. Specifically, a particle having a particle size of 2 to 100 nm is referred to as a “fine particle material”, and is defined as “a fine particle material” to distinguish it from inorganic particles.

  In addition, “residual liquid” is a limitation added with the intention of excluding those that disappear when the reaction is actively advanced. A liquid that only adheres to the surface or inside of inorganic particles, such as a general organic solvent or water, is a “residual liquid”. When a surface treatment agent such as a silane coupling agent is a liquid, it is a compound that reacts with inorganic particles, and thus is not included in the “residual liquid” defined in this specification. On the other hand, even if the surface treatment agent is used as a solvent for dissolving, if the product itself does not react, it is included in the “remaining liquid”. For example, when surface treatment is performed, the solvent used when the surface treatment agent is dissolved in a solvent is “residual liquid”.

  One or more of the characteristics described in the following (2) to (5) can be adopted for the inorganic filler disclosed in the above (1).

(2) The powder fluidity is 1200 mJ or less. The value of the powder fluidity is a value measured with a powder rheometer (model number: FT4, manufactured by TA Instruments Japan Co., Ltd.). This is energy when the propeller rotated in the powder is lowered under a predetermined condition, and the smaller is the higher the fluidity.
(3) The fine particle material is silica particles, and the degree of hydrophobicity is 20% or more. Due to the high degree of hydrophobicity, aggregation between fine particles can be suppressed, and high dispersibility can be maintained in a powder state.
(4) The fine particle material has a primary particle volume average particle size of 100 nm or less, a bulk density of 450 g / L or less, and a functional group represented by the formula (A): -OSiX ¹ X ² X ³ ; It has a functional group represented by the formula (B): —OSiY ¹ Y ² Y ³ on the surface. (In the above formulas (A) and (B); X ¹ is a phenyl group, vinyl group, epoxy group, methacryl group, amino group, ureido group, mercapto group, isocyanate group, or acrylic group; X ² , X ³ Are independently selected from —OSiR ₃ and —OSiY ⁴ Y ⁵ Y ⁶ ; Y ¹ is R; Y ² and Y ³ are each independently selected from R and —OSiY ⁴ Y ⁵ Y ⁶ .Y ⁴ is an R; ^{Y 5} and ^{Y 6} is selected from R and -OSiR ₃ independently;. R is independently selected from alkyl groups of 1 to 3 carbon atoms Incidentally, ^{X 2} , X ³ , Y ² , Y ³ , Y ⁵ , and Y ⁶ are any of the adjacent functional groups X ² , X ³ , Y ² , Y ³ , Y ⁵ , and Y ⁶ , and —O—. May be combined with each other.)
(5) The inorganic particles are silica or alumina. Silica and alumina are inexpensive and have excellent thermal properties.

(6) The manufacturing method of the inorganic filler of the present invention that solves the above problem is a manufacturing method of manufacturing the inorganic filler according to any one of (1) to (5),
An inorganic particle production process for producing the inorganic particles by a VMC method or a flame melting method;
A classification step in which the inorganic particles and the fine particle material are mixed and classified in a state dispersed in a gas;
Have
In this case, the inorganic particles obtained in the inorganic particle manufacturing process are not in contact with the remaining liquid.
As a result, no liquid remains in the obtained inorganic filler, and the amount of coarse particles having a particle size of 5 μm or more can be limited.

(7) The resin composition of the present invention that solves the above-described problems is an inorganic filler according to any one of the above (1) to (5);
A curable resin material in which the inorganic filler is dispersed;
Have

(8) The molded product of the present invention that solves the above-described problems can be obtained by curing the resin composition described in (7) above.

It is a SEM photograph when 0.3% of microparticle material B is mixed with 0.5 μm silica particles. It is a SEM photograph when 1.0% of fine particle material B is mixed with 0.5 μm silica particles. It is a SEM photograph when 3.0% microparticle material B is mixed with 0.5 μm silica particles. It is a SEM photograph when 0.3% of fine particle material A is mixed with 0.5 μm silica particles. It is a SEM photograph when 1.0% of microparticle material A is mixed with 0.5 μm silica particles. It is a graph which shows the fine particle material addition amount dependence in the value of the powder fluidity | liquidity of an inorganic particle.

(Inorganic filler)
The inorganic filler of the present invention and the production method thereof will be described below based on the embodiments. The inorganic filler of the present embodiment includes 100 parts by mass of inorganic particles having a volume average particle diameter of 0.1 μm to 3 μm, and 0.01 part by mass to 10% by mass of a fine particle material having a hydrophobic surface and a particle diameter of 2 to 100 nm. It is a mixture which has a mass part. Examples of the content of the fine particle material include 0.1 parts by mass or more, more than 0.1 parts by mass, and 0.15 parts by mass or more, and examples include 5 parts by mass or less and 3 parts by mass or less.

  In the inorganic filler of the present embodiment, 99% or more of particles on a mass basis are present in a primary particle state. The inorganic filler of this embodiment is manufactured without forming the inorganic particles and then dispersing them in the remaining liquid. In the inorganic filler of the present embodiment, the mass of coarse particles having a particle diameter of 5 μm or more is less than 100 ppm based on the total mass. Preferably, they are 70 ppm, 50 ppm, 20 ppm, 10 ppm, 5 ppm, and less than 5 / 10,000. Coarse particles are removed by a classification operation performed in a dry process. Furthermore, examples of the particle size of the coarse particles to be removed include 4 μm, 3 μm, and 2 μm. Here, in addition to defining the content ratio of coarse particles, the content ratio including particles having a smaller particle diameter than the coarse particles can also be defined. For example, 500 ppm, 100 ppm, 50 ppm, etc. can be adopted as the lower limit of the abundance of particles having lower limits of 4 μm, 3 μm, 2 μm, 1 μm.

The content of coarse particles is determined by dispersing the inorganic filler in an appropriate dispersion medium (water, alcohol, ketone-based organic solvent, etc.), passing through a filter with an opening of 5 μm, and measuring the amount of filler captured by the filter. To convert.
It can be evaluated by image analysis that 99% or more are primary particles.

Inorganic particles The inorganic particles have a volume average particle diameter of 0.1 μm to 3 μm. Examples of the preferable upper limit of the volume average particle include 1 μm, 1.5 μm, and 2 μm, and examples of the preferable lower limit include 0.5 μm, 0.3 μm, and 0.1 μm. These upper and lower limits can be arbitrarily combined.

  The material constituting the inorganic particles is not particularly limited. Examples thereof include metals (metal silicon, aluminum, titanium, zirconium, iron, etc.), oxides and nitrides of those metals. Particularly preferable examples are silica and alumina.

Examples of the form of the inorganic particles include a spherical shape, a true spherical shape, a crushed material, a crystal as it is, and the like. The inorganic particles are preferably spherical. For example, the sphericity is preferably 0.9 or more, 0.95 or more, and 0.99 or more. The sphericity is measured by taking a photograph with an SEM, and calculating the value as (sphericity) = {4π × (area) ÷ (perimeter) ² } from the area and circumference of the observed particle. To do. The closer to 1, the closer to a true sphere. Specifically, an average value measured for 100 particles using an image processing apparatus (Sysmex Corporation: FPIA-3000) is employed.

  In order to improve the sphericity, there is a means for forming inorganic particles by a melting method or a VMC method. In the melting method, the material constituting the inorganic particles is powdered by pulverization or the like and then put into a flame having a temperature equal to or higher than the melting point. When the powder is melted and liquefied, it is spheroidized by surface tension. Then, by separating from the flame, the melt is cooled and spherical inorganic particles are obtained. The VMC method is a method that can be adopted when the material constituting the inorganic particles is a specific compound. For example, when the material constituting the inorganic particles is an oxide, the substance used as a raw material before oxidation of the oxide (the metal when the oxide is a metal oxide. When the metal oxide is silica, This is a method of obtaining the desired oxide by pulverizing metal silicon or metal aluminum when the metal oxide is alumina) by pulverizing it, etc., and injecting it into an atmosphere to ignite and react. . The inorganic substance obtained by the reaction proceeding explosively evaporates and spheroidizes in the subsequent cooling process. There is a possibility that spherical inorganic particles can be obtained by heating in an atmosphere containing nitrogen if it is a nitride, or by proceeding the reaction in an atmosphere containing the corresponding element if it is another compound.

  The VMC method will be specifically described. A chemical flame is formed by burning a combustor (hydrocarbon gas, etc.) with a burner in an oxygen-containing atmosphere, and metal particles are introduced into the chemical flame in such an amount that a dust cloud is formed. This is a method for obtaining metal oxide particles.

The operation of the VMC method will be described as follows. First, the container is filled with a gas containing oxygen as a reaction gas, and a chemical flame is formed in the reaction gas. Next, metal particles are introduced into the chemical flame to form a dust cloud with a high concentration (for example, 500 g / m ³ or more). Then, thermal energy is given to the metal particle surface by the chemical flame, the surface temperature of the metal particle rises, and the vapor of the metal material spreads from the metal particle surface to the surroundings. This vapor reacts with oxygen gas to ignite and produce a flame. The heat generated by the flame further promotes vaporization of the metal particles, and the generated steam and oxygen gas are mixed and propagated in a chain. Therefore, as the particle size of the metal particles is smaller, the specific surface area is larger and the reactivity is improved, so that the input energy can be reduced.

  As the chain firing proceeds in this way, the metal particles themselves are also destroyed and scattered to promote flame propagation. The product gas is naturally cooled after combustion, thereby forming a cloud of metal oxide particles. The obtained metal oxide particles are collected by a bag filter, an electric dust collector or the like.

  The VMC method uses the principle of dust explosion. According to the VMC method, a large amount of metal oxide particles can be obtained instantaneously. The obtained metal oxide particles have a substantially spherical shape. It is possible to adjust the particle size distribution of the metal oxide particles obtained by adjusting the particle size of the metal particles to be input, the input amount, the flame temperature, and the like. In addition to the metal particles alone, the metal oxide particles can also be added as the raw material. The metal oxide particles added simultaneously can maintain the purity of the metal oxide particles obtained by employing the metal oxide particles obtained by this method. The metal particles can be surface treated. For the surface treatment, a reaction introduced into the surface using a surface treatment agent having a hydrophobic group (such as an alkyl group) can be employed.

  The inorganic particles are not brought into contact with “residual liquid” after they are produced. Not contacting can be determined by analyzing gas generated by heating a predetermined amount of inorganic particles (or the inorganic filler of the present embodiment) (heating determination method). If the total mass of the inorganic particles is 100 ppm or less, it is assumed that no contact is made with the remaining liquid. In addition, since the organic functional group has couple | bonded with the surface when surface treatment is performed, the temperature of heating is set to the temperature which does not decompose | disassemble these organic functional groups.

  It is not important at what point the “residual liquid” is liquid. Specifically, it is assumed that the liquid is in contact with the liquid, but it is difficult to determine later whether or not the liquid is in contact with the liquid. Judgment is made based on whether or not it is determined that there is not.

  As described above, the “residual liquid” is a limitation added with the intention of excluding those that disappear when the reaction is actively advanced. A liquid that only adheres to the surface or inside of inorganic particles, such as a general organic solvent or water, is a “residual liquid”. When a surface treatment agent such as a silane coupling agent is a liquid, it is a compound that reacts with inorganic particles, and thus is not included in the “residual liquid” defined in this specification. On the other hand, even if the surface treatment agent is used as a solvent for dissolving, if the product itself does not react, it is included in the “remaining liquid”. For example, when surface treatment is performed, the solvent used when the surface treatment agent is dissolved in a solvent is “residual liquid”.

  The inorganic particles may be subjected to a surface treatment. The surface treatment is performed by directly contacting the surface of the inorganic particles without dissolving the surface treatment agent in the solvent. As the surface treatment agent, the same surface treatment agent as described for the fine particle material described later can be employed.

Fine particle material (explained by taking silica particles as an example. Hereinafter, “fine particle material” may be referred to as “silica particles” as appropriate)
The fine particle material is a particle having a predetermined particle size range. The fine particle material has a particle size of 2 nm to 100 nm. In the inorganic filler of the present embodiment, particles having this particle size range are included at a predetermined ratio based on the total mass. The microparticle material can improve the fluidity of the inorganic material by having a particle size in this range. The fine particle material preferably has an upper limit of the primary particle size of 100 nm. The lower limit is preferably 10 nm. As a preferable upper limit of a particle size, 100 nm, 70 nm, 50 nm, 30 nm, and 20 nm are mentioned. Moreover, 10 nm is mentioned as a preferable minimum.

  The microparticulate material has a hydrophobized surface. Here, as long as it has a hydrophobized surface, it is sufficient if it is hydrophobized as compared with the material itself constituting the fine particle material. As a preferable degree of hydrophobicity, the degree of hydrophobicity is 20% or more, and more preferably 40% or more. By making the degree of hydrophobicity within this range, aggregation by itself can be suppressed, and adhesion to the surface of the inorganic material is improved. As a result, the fluidity of particles made of an inorganic material can be improved.

The measurement of the degree of hydrophobicity is as follows. A stir bar is placed in the flask, 50 ml of ion-exchanged water is weighed, and 0.2 g of the sample is gently floated on the water surface. Rotate the stir bar and gently drop the methanol so that it does not get directly on the sample. The degree of hydrophobicity is calculated from the amount of methanol when all the samples settle from the water surface.
(Hydrophobicity:%) = 100 × (Methanol drop amount (mL)) ÷ (50 mL + Methanol drop amount (mL))

  It is desirable that the fine particle material is a material whose powder fluidity can be reduced to 1200 mJ or less by mixing with the inorganic particle material.

The means for hydrophobizing the surface and lowering the powder flowability value is not particularly limited, but examples thereof include a method of introducing the following functional groups to the surface. That is, it is desirable to have a functional group represented by the formula (A): —OSiX ¹ X ² X ³ and a functional group represented by the formula (B): —OSiY ¹ Y ² Y ³ on the surface. (In the above formulas (A) and (B); X ¹ is a phenyl group, vinyl group, epoxy group, methacryl group, amino group, ureido group, mercapto group, isocyanate group, or acrylic group; X ² , X ³ Are independently selected from —OSiR ₃ and —OSiY ⁴ Y ⁵ Y ⁶ ; Y ¹ is R; Y ² and Y ³ are each independently selected from R and —OSiY ⁴ Y ⁵ Y ⁶ .Y ⁴ is an R; ^{Y 5} and ^{Y 6} is selected from R and -OSiR ₃ independently;. R is independently selected from alkyl groups of 1 to 3 carbon atoms Incidentally, ^{X 2} , X ³ , Y ² , Y ³ , Y ⁵ , and Y ⁶ are any of the adjacent functional groups X ² , X ³ , Y ² , Y ³ , Y ⁵ , and Y ⁶ , and —O—. May be combined with each other.)

  The bulk density is desirably 450 g / L or less. The measurement of the bulk density in this specification is performed using the Tsutsui-Rikagakuki Co., Ltd. product: electromagnetic vibration type | mold beak density measuring device (MVD-86 type | mold). Specifically, after the sample to be measured is put into the upper 500 μm sieve as the sample tank, the sample is dispersed through the two upper and lower 500 μm sieves under electromagnetic acceleration conditions, and dropped into a 100 mL sample container. The mass was measured, and the bulk density was calculated from the mass and volume. In order to prevent a decrease in bulk density due to its own weight, measurement should be performed within 1 hour after dropping.

  Preferred upper limits for the bulk density include 400 g / L, 370 g / L, 350 g / L, 300 g / L, 280 g / L, and 250 g / L. A preferred lower limit is 100 g / L. By setting the bulk density to a value below these upper limits, primary particles can be separated more reliably. Moreover, when the bulk density is set to a value higher than these lower limits, the bulk is small and the handling becomes easy.

  When the fine particle material is formed from silica, it is produced by crushing raw material silica particles having a predetermined particle size distribution. Surface treatment or the like can be performed as necessary. The pulverization step is performed until the raw material silica particles are substantially in a state close to primary particles (determining whether or not they are primary particles by a determination method described later).

  The method for the crushing step is not particularly limited. Preferably, a method of adding an effect of separating the aggregates of the aggregates is preferable, and a method that does not destroy the primary particles constituting the aggregates is preferable. For example, it can be performed by a method similar to pulverization performed in a dry state, and examples thereof include a jet mill, a pin mill, and a hammer mill. It is particularly desirable to use a jet mill. The final stage of the process is judged from the value of the bulk density of the raw silica particles. After the proper bulk density, it can be selected from the range described above. The jet mill is a device that performs pulverization by placing raw material silica particles in an air stream. Any type of jet mill is acceptable. Crushing by a jet mill is desirably performed by a dry method.

  The raw material silica particles have a primary particle size volume average particle size of 100 nm or less. In addition, examples of the upper limit include 70 nm and 50 nm. The method for producing the raw material silica particles is not particularly limited. For example, a water glass method, an alkoxide method, and a VMC method can be exemplified, and it is desirable to employ the water glass method. The water glass method is a method of precipitating raw material silica particles by performing ion exchange, introduction / desorption of substituents by chemical reaction, control of pH, temperature, and the like on water glass. For example, an aqueous slurry in which nanometer order silica particles are dispersed can be prepared by ion exchange of water glass with an ion exchange resin. The particle diameter of the secondary particles constituting the raw silica particles is not particularly limited, but the volume average particle diameter may be 10 μm or more, 100 μm or more. Furthermore, the raw material silica particles can be produced by dissolving metal silicon in an alkali solution or the like and then depositing it (a method similar to the water glass method).

  A pretreatment process is applied to the preparation of the raw silica particles. The pretreatment process includes a surface treatment process and a process for removing the liquid medium (solidification process). The surface treatment step is a step of performing a surface treatment with a silane coupling agent and an organosilazane in a liquid medium containing water (water, one containing alcohol in addition to water). The silane coupling agent has three alkoxy groups and a phenyl group, vinyl group, epoxy group, methacryl group, amino group, ureido group, mercapto group, isocyanate group, or acrylic group. The molar ratio of the silane coupling agent to the organosilazane is (silane coupling agent) :( organosilazane) = 1: 2 to 1:10.

  The surface treatment step includes a first treatment step for treating with the above-described silane coupling agent and a second treatment step for treating with organosilazane thereafter.

In the surface treatment step, the functional group represented by the formula (A): -OSiX ¹ X ² X ³ and the formula (B): -OSiY ¹ Y ² Y are applied to the silica particles obtained by the above-described method. ³ is a step of obtaining raw material silica particles in which the functional group represented by ³ is bonded to the surface. Hereinafter, the functional group represented by the formula (A) is referred to as a first functional group, and the functional group represented by the formula (B) is referred to as a second functional group.

X ¹ in the first functional group is a phenyl group, vinyl group, epoxy group, methacryl group, amino group, ureido group, mercapto group, isocyanate group, or acrylic group. X ² and X ³ are —OSiR ₃ or —OSiY ⁴ Y ⁵ Y ⁶ , respectively. Y ⁴ is R. Y ⁵ and Y ⁶ are each R or —OSiR ₃ .

Y ¹ in the second functional group is R. Y ² and Y ³ are each —OSiR ₃ or —OSiY ⁴ Y ⁵ Y ⁶ .

The more —OSiR ₃ contained in the first functional group and the second functional group, the more R on the surface of the raw silica particles. As the R (the alkyl group having 1 to 3 carbon atoms) contained in the first functional group and the second functional group increases, the raw silica particles are less likely to aggregate.

Regarding the first functional group, when X ² and X ³ are each —OSiR ₃ , the number of R is minimized. Further, ^{X 2} and ^{X 3} is -OSiY ⁴ Y ⁵ Y ^6, respectively, ^and, if Y 5, ^{Y 6} is -OSiR ₃ respectively, the number of R is maximized.

Regarding the second functional group, when Y ² and Y ³ are each —OSiR ₃ , the number of R is minimized. Further, ^{Y 2} and ^{Y 3} are -OSiY ⁴ Y ⁵ Y ^6, respectively, ^and, if Y 5, ^{Y 6} is -OSiR ₃ respectively, the number of R is maximized.

The number of X ¹ contained in the first functional group, the number of R contained in the first functional group, and the number of R contained in the second functional group are the abundance ratio of R and X ¹ What is necessary is just to set suitably according to the particle size and use of a silica particle.

^{Incidentally, X 2, X 3, Y} 2, Y 3, Y 5, and any of ^{Y 6, X} 2 of the adjacent ^{functionality, X 3, Y 2, Y} 3, Y 5, and any ^{Y 6} You may combine with heel -O-. For example, any one of the first functional group X ² , X ³ , Y ⁵ , and Y ⁶ is the first functional group adjacent to the first functional group X ² , X ³ , Y ⁵ , and It may be bonded to any of Y ⁶ by —O—. Similarly, any of Y ² , Y ³ , Y ⁵ , and Y ⁶ of the second functional group is replaced with Y ² , Y ³ , Y ⁵ , Y ² of the second functional group adjacent to the second functional group. And Y ⁶ may be bonded to each other by —O—. Furthermore, any one of the first functional groups X ² , X ³ , Y ⁵ , and Y ⁶ is the second functional group adjacent to the first functional group, Y ² , Y ³ , Y ⁵ , And Y ⁶ may be bonded to each other by —O—.

In the raw material silica particles, the presence ratio of the first functional groups and second functional groups is 1: 12-1: if 60, the surface of the raw material silica particles and X ¹ and R are present good balance. For this reason, the raw material silica particle whose abundance ratio of the first functional group and the second functional group is 1:12 to 1:60 is particularly excellent in the affinity for the resin and the aggregation suppressing effect. Further, if X ¹ is 0.5 to 2.5 per unit surface area (nm ² ) of the raw silica particles, a sufficient number of first functional groups are bonded to the surface of the raw silica particles, and the first There are also a sufficient number of Rs derived from the functional group and the second functional group. Therefore, also in this case, the affinity for the resin and the aggregation suppressing effect of the raw silica particles are sufficiently exhibited.

In any case, R per unit surface area (nm ² ) of the raw silica particles is preferably 1 to 10. In this case, the balance between the number of X ¹ present on the surface of the raw silica particles and the number of R is improved, and both the affinity for the resin and the aggregation suppressing effect of the raw silica particles are exhibited in a well-balanced manner.

In the raw material silica particles, it is preferable that all of the hydroxyl groups present on the surface of the silica particles are substituted with the first functional group or the second functional group. If the sum of the first functional group and the second functional group is 2.0 or more per unit surface area (nm ² ) of the raw silica particles, the raw silica particles were present on the surface of the silica particles. It can be said that almost all of the hydroxyl groups are substituted with the first functional group or the second functional group.

The raw silica particles have R on the surface. This can be confirmed by an infrared absorption spectrum. Specifically, when the infrared absorption spectrum of the raw silica particles is measured by the solid diffuse reflection method, there is a maximum absorption of C—H stretching vibration at 2962 ± 2 cm ⁻¹ .

  Further, as described above, the raw material silica particles hardly aggregate.

  Note that the raw silica particles can be dispersed again by ultrasonic treatment even if they are slightly agglomerated. Specifically, the raw silica particles can be substantially dispersed to primary particles by irradiating the raw silica particles dispersed in methyl ethyl ketone with ultrasonic waves having an oscillation frequency of 39 kHz and an output of 500 W. The ultrasonic irradiation time at this time may be 10 minutes or less. Whether or not the raw material silica particles are dispersed to the primary particles can be confirmed by measuring the particle size distribution. Specifically, when the methyl ethyl ketone dispersion material of the raw material silica particles is measured with a particle size distribution measuring device such as a microtrack device, and there is a particle size distribution of the raw material silica particles, it can be said that the raw material silica particles are dispersed to primary particles.

The raw material silica particles are treated in a step of treating the silica particles with a silane coupling agent and an organosilazane (surface treatment step) in a liquid medium containing water. The silane coupling agent has three alkoxy groups and a phenyl group, a vinyl group, an epoxy group, a methacryl group, an amino group, a ureido group, a mercapto group, an isocyanate group, or an acrylic group (that is, X ¹ described above). It does not prevent the adoption of the aforementioned N-phenyl-3-aminopropyltrimethoxysilane.

By performing the surface treatment with the silane coupling agent, the hydroxyl group present on the surface of the silica particles is substituted with a functional group derived from the silane coupling agent. The functional group derived from the silane coupling agent is represented by the formula (3); —OSiX ¹ X ⁴ X ⁵ . The functional group represented by the formula (3) is referred to as a third functional group. X ¹ in the third functional group is the same as X ¹ in the functional group represented by the formula (A). X ⁴ and X ⁵ are each an alkoxy group. Surface treatment with organosilazane allows X ⁴ and X ⁵ of the third functional group to be derived from organosilazane —OSiY ¹ Y ² Y ³ (functional group represented by formula (B), second functional group ). When all of the hydroxyl groups present on the surface of the silica particles are not substituted with the third functional group, the hydroxyl groups remaining on the surface of the silica particles are substituted with the second functional group. For this reason, on the surface of the surface-treated raw material silica particles, a functional group represented by the formula (A): —OSiX ¹ X ² X ³ (that is, a first functional group) and a formula (B): —OSiY ^The functional group represented by ¹ Y ² Y ³ is bonded to the functional group (that is, the second functional group). In addition, since the molar ratio of the silane coupling agent and the organosilazane is silane coupling agent: organosilazane = 1: 2 to 1:10, the first functional group and the second functional group in the obtained raw material silica particles are used. The abundance ratio with the functional group is theoretically from 1:12 to 1:60.

In the surface treatment step, the silica particles may be simultaneously surface treated with a silane coupling agent and an organosilazane. Alternatively, the silica particles may first be surface treated with a silane coupling agent and then surface treated with organosilazane. Alternatively, the silica particles may be first surface treated with organosilazane, then surface treated with a silane coupling agent, and then surface treated with organosilazane. In any case, the amount of organosilazane may be adjusted so that all the hydroxyl groups present on the surface of the silica particles are not substituted with the second functional group. The hydroxyl groups present on the surface of the silica particles may all be substituted with the third functional group, or only a part may be substituted with the third functional group, and the other part may be substituted with the second functional group. It may be replaced. All of X ⁴ and X ⁵ contained in the third functional group may be substituted with the second functional group.

A part of organosilazane may be replaced with the second silane coupling agent. As the second silane coupling agent, one having three alkoxy groups and one alkyl group can be used. In this case, X ⁴ and X ⁵ contained in the third functional group are substituted with the fourth functional group derived from the second silane coupling agent. The fourth functional group has the formula (4); - represented by OSiY ¹ X ⁶ X ^7. Y ¹ is the same R as ^{Y 1} in the second functional ^{group, X 6,} X ⁷ is an alkoxy group or a hydroxyl group, respectively. X ⁶ and X ⁷ contained in the fourth functional group are substituted with the second functional group derived from organosilazane, or are substituted with another fourth functional group. In this case, the amount of R present on the surface of the raw silica particles can be further increased. When a part of the organosilazane is replaced with the second silane coupling agent, it is necessary to surface-treat with the organosilazane again after the surface treatment with the second silane coupling agent. This is because X ⁶ and X ⁷ contained in the fourth functional group are finally substituted with the second functional group derived from organosilazane.

When a part of the organosilazane is replaced with the second silane coupling agent, X ⁴ and X ⁵ contained in the first functional group described above are substituted with the second functional group derived from the organosilazane, Substitution with a fourth functional group derived from the second silane coupling agent. When X ⁴ and X ⁵ are substituted with the fourth functional group, X ⁶ and X ⁷ contained in the fourth functional group are substituted with the second functional group or another fourth functional group. Is replaced by If X ^6, X ⁷ contained in the fourth functional group has been replaced by another fourth functional group, X ^6, X ⁷ contained in the fourth functional groups is substituted with the second functional group The For this reason, the second silane coupling agent is an organosilazane set when the surface treatment is performed only with the first coupling agent and the organosilazane (when the organosilazane is not replaced with the second silane coupling agent). A maximum of 5a / 3 mol can be substituted for the amount (a) mol. The amount of organosilazane required in this case is 8a / 3 mol.

  The alkoxy groups of the silane coupling agent and the second silane coupling agent are not particularly limited, but those having a relatively small carbon number are preferred, and those having 1 to 12 carbon atoms are preferred. Considering the hydrolyzability of the alkoxy group, the alkoxy group is more preferably any one of a methoxy group, an ethoxy group, a propoxy group, and a butoxy group.

  Specific examples of silane coupling agents include phenyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane. 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-phenyl-3 -Aminopropyltrimethoxysilane.

  Any organosilazane may be used as long as it can replace the hydroxyl group present on the surface of the silica particles and the alkoxy group derived from the silane coupling agent with the second functional group described above. preferable. Specific examples include tetramethyldisilazane, hexamethyldisilazane, pentamethyldisilazane, and the like.

  Examples of the second silane coupling agent include methyltrimethoxysilane, methyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, and hexyltriethoxysilane.

  In the surface treatment step, a polymerization inhibitor may be added in order to suppress polymerization of the silane coupling agent or polymerization of the second silane coupling agent. As the polymerization inhibitor, common ones such as 3,5-dibutyl-4-hydroxytoluene (BHT) and p-methoxyphenol (methoquinone) can be used.

-Classification operation performed by dry method Before performing the classification operation, the inorganic particles and the fine particle material are mixed in the above-described ratio to perform the classification operation. From this mixing to the classification operation is carried out dry. Classification operation can be performed by centrifugal classification, sieving or the like. Centrifugal classification is performed by introducing a mixture into a gas that moves toward the center of rotation while swirling. In principle, it will be divided into whether it moves to the center of the swirl flow at a certain particle diameter or moves to the outside. This certain particle size can be controlled by adjusting the magnitude of the gas moving speed and the turning speed. Here, if both the gas moving speed and the swirl speed can be increased, the classification accuracy can be improved. However, if the fine particle material is not added as in the present invention, the classification equipment is increased by the increased centrifugal force. As a result of the adhesion and clogging of inorganic particles to the surface, air currents were disturbed and clogged, and coarse particles could not be removed effectively.

  When classification is performed with a sieve, coarse particles can be removed with a sieve having a predetermined opening. Examples of the predetermined opening include 5 μm, 4.5 μm, 4 μm, and 3.5 μm.

(Resin composition)
The resin composition of the present invention will be described in detail below. The resin composition of this embodiment has the above-mentioned inorganic filler and resin material. This resin composition can be cured later, and can be suitably used as a sealing material for semiconductor elements and a substrate.

  A resin material that can exhibit fluidity in the final resin composition state can be employed. The resin material contains one or more compounds and is either one that melts by heating and exhibits fluidity (such as a thermoplastic resin) or one that is initially liquid and solidifies by reaction (such as a thermosetting resin). May be. As a preferable resin material, a combination of an epoxy resin and a curing agent can be exemplified.

  The mixing ratio of the inorganic filler and the resin material is not particularly limited, but as a result of improving the fluidity by mixing the fine particle material, a large amount of inorganic filler can be contained. For example, the filler can be contained in an amount of 60% or more, further 75% or more, 80% or more based on the total mass. Although it does not specifically limit as an upper limit, About 95%, 90%, and 85% are mentioned. These upper and lower limits can be arbitrarily combined.

(Molded body)
The molded product of the present invention is obtained by curing the above-described resin composition. As described above, a semiconductor element sealing body, a substrate, and the like can be exemplified.

  The inorganic filler, resin composition, and molded body of the present invention will be described in detail based on examples.

  Silica and alumina were used as the inorganic particles. Silica having a volume average particle diameter of 0.5 to 6 μm was used, and alumina having a volume average particle diameter of 0.6 μm was used. Table 1 shows the values of the powder flowability of the inorganic particles.

  Table 1 also shows the mixing ratio of these inorganic particles and the above-mentioned fine particles. As the fine particle material, 10 nm particle size phenylsilane treated product (manufactured by Admatechs), 10 nm particle size vinylsilane treated product (manufactured by Admatechs), 10 nm particle size methacrylsilane treated product (manufactured by Admatex), 50 nm phenylsilane treated Product (manufactured by Admatechs) was used.

  The inorganic particles and the fine particles were mixed and the silica particles were adhered to the surface of the particles to obtain the particles of each test example. The powder flowability of the mixture is also shown in Table 1.

  Classification operation was performed about the granular material of each test example. Centrifugal classification was performed as a classification method. Centrifugation conditions (mainly adjusting the swirl speed: controllable by the amount of gas introduced) were such that coarse particles having a particle size of 5 μm or more were less than 100 ppm for those added with a fine particle material.

  As a result of classification, it was possible to continue the classification without any problem in all the test examples in which the fine particle material was mixed, but in the test in which the fine particle material was not mixed, adhesion and clogging of the powder particles occurred rapidly. Furthermore, when silica particles differing only in that the particle size distribution was the same and not surface-treated were included, classification could be continued for a longer time than in the control test. Adhesion and clogging occurred in a shorter time than when added.

(Evaluation of coarse particle amount)
The content of coarse particles is determined by dispersing the inorganic filler in an appropriate dispersion medium (selected from organic solvents such as water, alcohol, and ketones) and passing through a sieve with an opening of 5 μm. Measured and converted.
In Test Examples 2-1 to 2-6, the number of coarse particles was large and could not pass through the sieve.

  For Test Example 2-7, classification with a sieve was carried out in a state of being dispersed in a dispersion medium (selected from organic solvents such as water, alcohol, and ketone), and the state of dispersion in the classified dispersion medium was maintained When the coarse particle amount evaluation was carried out, all the particles passed through the sieve, but as a result of removing and drying the dispersion medium, the silica particles were agglomerated.

  The amount of coarse particles could be reduced for any of phenyltrimethoxysilane, vinyltrimethoxysilane, and 3-methacryloxypropyltrimethoxysilane. In Table 1, the amount of coarse particles being 0 ppm means less than 0.5 ppm. That is, it is less than 5 / 10,000.

・ Investigation of the dependence of the powder flowability of inorganic particles on the amount of fine particle material added How the powder flowability changes depending on the amount of fine particle material added to silica particles with different particle sizes as inorganic particles Examined. The results are shown in Table 2. Silica particles have particle sizes of 0.3 μm (manufactured by Admatechs: SO-C1), 0.5 μm (manufactured by Admatechs: SO-C2), 1 μm (manufactured by Admatechs: SO-C4), 2 μm (Admatechs). A product manufactured by: SO-C6) was used. As the fine particle material, the volume average particle diameter was 10 nm, and the surface treating agent was phenyltrimethoxysilane (fine particle material A). For comparison, the result of using a microparticle material whose surface is not hydrophobized (microparticle material B: Aerosil MT-10 manufactured by Tokuyama Corporation) is also shown.

  It was found that the value of the powder fluidity tends to decrease as the addition amount of the fine particle material is increased with respect to each inorganic particle. In particular, in the region where the addition amount was less than 1%, a sharp decrease in the powder fluidity value was observed. For the fine particle material whose surface is not hydrophobized, the degree of decrease in the value of the powder fluidity is moderate compared to the fine particle material having a hydrophobized surface.

  An SEM photograph was taken when the fine particle material A was mixed with 0.5 μm silica particles. 0.3% is FIG. 1 and 1.0% is FIG. Similarly, an SEM photograph was taken when the fine particle material B was mixed with 0.5 μm silica particles. 0.3% is FIG. 3, 1.0% is FIG. 4, and 3.0% is FIG.

  As is clear from FIGS. 1 to 5, the microparticle material B aggregates with the microparticle material B itself, whereas the microparticle material A disperses neatly and adheres uniformly to the surface of the silica particles. I understood that.

  It has been found that, when dispersed in the resin material, increasing the amount of the fine particle material mixed increases the viscosity, so that a smaller amount is preferable. For example, the addition amount is preferably 10% or less, and more preferably 3% or less.

Claims (8)

100 parts by mass of inorganic particles having a volume average particle size of 0.1 μm to 3 μm,
A mixture having 0.01 to 10 parts by mass of a fine particle material having a hydrophobic surface and a particle diameter of 2 to 100 nm,
An inorganic filler which is manufactured without a step of dispersing in the remaining liquid after forming the inorganic particles, and the mass of coarse particles having a particle diameter of 5 μm or more is less than 100 ppm based on the total mass.   The inorganic filler according to claim 1, wherein the powder fluidity is 1200 mJ or less.   The inorganic filler according to claim 1 or 2, wherein the fine particle material is silica particles and has a hydrophobicity of 20% or more. The fine particle material has a primary particle volume average particle size of 100 nm or less, a bulk density of 450 g / L or less, a functional group represented by the formula (A): —OSiX ¹ X ² X ³ , and a formula (B ): The inorganic filler according to claim 1, which has a functional group represented by —OSiY ¹ Y ² Y ³ on its surface.
(In the above formulas (A) and (B); X ¹ is a phenyl group, vinyl group, epoxy group, methacryl group, amino group, ureido group, mercapto group, isocyanate group, or acrylic group; X ² , X ³ Are independently selected from —OSiR ₃ and —OSiY ⁴ Y ⁵ Y ⁶ ; Y ¹ is R; Y ² and Y ³ are each independently selected from R and —OSiY ⁴ Y ⁵ Y ⁶ .Y ⁴ is an R; ^{Y 5} and ^{Y 6} is selected from R and -OSiR ₃ independently;. R is independently selected from alkyl groups of 1 to 3 carbon atoms Incidentally, ^{X 2} , X ³ , Y ² , Y ³ , Y ⁵ , and Y ⁶ are any of the adjacent functional groups X ² , X ³ , Y ² , Y ³ , Y ⁵ , and Y ⁶ , and —O—. May be combined with each other.)   The inorganic filler according to any one of claims 1 to 4, wherein the inorganic particles are silica or alumina. It is a manufacturing method which manufactures the inorganic filler in any one of Claims 1-5,
An inorganic particle production process for producing the inorganic particles by a VMC method or a flame melting method;
A classification step in which the inorganic particles and the fine particle material are mixed and subjected to centrifugal classification in a state dispersed in a gas;
Have
The manufacturing method of the inorganic filler in which the said inorganic particle obtained at the said inorganic particle manufacturing process is not contacting the said remaining liquid. An inorganic filler according to any one of claims 1 to 5;
A curable resin material in which the inorganic filler is dispersed;
A resin composition having   A molded article obtained by curing the resin composition according to claim 7.