JP6209032B2 - Classified particle material, method for producing the same, and resin composition - Google Patents

Description

  The present invention relates to a classified particle material, a method for producing the same, and a resin composition.

  I do not know where miniaturization of electronic devices (including electronic components) in recent years will stop. A material used for such an electronic device is required to have very high performance corresponding to its size. For example, a semiconductor device that is one of electric parts is generally manufactured by sealing a semiconductor element with a sealing material. The sealing material is required to have various performances such as isolating the semiconductor element from the outside and ensuring heat dissipation. However, with the miniaturization of semiconductor devices, very high performance is required.

  As a sealing material, a material in which silica is dispersed as a filler is widely used in order to have high physical and chemical stability and to reduce volume fluctuation due to thermal fluctuation. Since the sealing material needs to be filled in a minute gap such as between the semiconductor element and the substrate, a fine filler is required for the dispersed filler. In addition, in order to improve the filling property in the gap, it is necessary to precisely control the particle size distribution of the filler.

JP 2008-247726 A JP 2011-213514 A

  By the way, a particle material having a small particle size (particularly a particle material of the order of micrometers or nanometers) often has high cohesiveness and is difficult to be classified accurately.

  Conventionally, as a method of classifying the particulate material, there are a method of passing through a sieve by a dry method, a method of passing through a sieve by a wet method, a method of using a fluid flow (wind, water), and the like. Of these, the dry method of passing through a sieve not only did not give a precise classification, but the classification yield was not sufficient. In the wet classification method, although the classification accuracy is good, the yield is not sufficient, and depending on the type of the material constituting the particulate material, aggregation may occur when dried after classification.

  It is also possible to obtain a particle material having a particle size distribution close to the target particle size distribution by mixing particle materials having various particle size distributions, but the particle material itself before mixing has a special particle size distribution ( It is desirable that the particles be classified precisely with a certain particle size as a boundary: classified particle material).

  The present invention has been completed in view of the above circumstances, and a method for producing a classified particle material capable of realizing precise classification, a precisely classified particle material, and a resin composition using the classified particle material Providing is a problem to be solved.

(1) The method for producing a classified particle material of the present invention that solves the above problems is crushed so that the bulk density is 450 g / L or less with respect to the raw material silica particles having a volume average particle diameter of primary particles of 200 nm or less. Crushing process to
A silica-coated particle material obtained by mixing the silica particles obtained in the crushing step and a particle material having a volume average particle size larger than the primary particles of the silica particles to adhere the silica particles to the surface of the particle material. And a mixing step
A classification step of classifying the silica-coated particle material with a dry sieve;
Have
The raw silica particles are
A surface treatment step of surface treatment with a silane coupling agent and an organosilazane in a liquid medium containing water;
Removing the liquid medium;
It is processed in the pretreatment process with
The silane coupling agent has three alkoxy groups, 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,
The molar ratio of the silane coupling agent to the organosilazane is the silane coupling agent: the organosilazane = 1: 2 to 1:10.

  By attaching the silica particles obtained by the above-mentioned crushing step to the surface of the particle material, the fluidity of the particle material can be improved, and as a result, the classification efficiency is also improved.

The invention (1) described above can be combined with the following (2). By combining these, silica particles are easily separated into primary particles by the crushing step. The classification efficiency can be improved as the proportion of primary particles increases.
(2) The surface treatment step includes
A first treatment step of treating with the silane coupling agent;
A second treatment step of treating with the organosilazane,
The second processing step is performed after the first processing step.
(3) The classified particle material of the present invention that solves the above-mentioned problem is a silica particle having a primary particle volume average particle size of 200 nm or less and a bulk density of 450 g / L or less,
A particle material having a volume average particle size larger than the primary particles of the silica particles and the silica particles adhering to the surface;
The silica particles have a functional group represented by the formula (1): -OSiX ¹ X ² X ³ and a functional group represented by the formula (2): -OSiY ¹ Y ² Y ³ on the surface. (In the above formulas (1) and (2); X ¹ is 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; 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 classified particle material of (3) described above can employ the configuration described in any one of the following (4) to (5).
(4) There are 5 or more silica particles per (300 nm) ^{2 on} the surface of the particle material.
(5) The mode diameter / cut point is 0.56 or more.
(6) The resin composition of the present invention that solves the above problems is the classified particle material according to any one of (3) to (5) above,
And a resin material in which the classified particle material is dispersed.

  In the method for producing a classified particle material of the present invention, the flow characteristics of the particle material can be improved by attaching silica particles to the surface of the particle material, and as a result, the classification efficiency can be improved. Therefore, the obtained classified particle material is a precisely classified particle material.

It is a particle size distribution after letting a sieve (10 micrometers) pass in an Example. It is a particle size distribution after letting a sieve (15 micrometers) pass in an Example. It is a particle size distribution after letting a sieve (20 micrometers) pass in an Example. It is a particle size distribution after letting a sieve (25 micrometers) pass in an Example. It is a SEM photograph in the test done in order to examine the density of adhesion of the test sample 1 to the particle | grain surface. It is a SEM photograph in the test done in order to examine the density of adhesion of the test sample 1 to the particle | grain surface.

  The production method of classified particle material, classified particle material, and resin composition of the present invention will be described below in detail based on the embodiments.

(Method for producing classified particulate material)
The method for producing a classified particle material according to the present embodiment is a method in which silica particles produced by performing a pulverization process on raw silica particles are attached to the surface of the particle material to form a silica-coated particle material, and then classified. . The raw material silica particles have a large proportion of primary particles bonded together, but the bonds can be separated in the crushing step. The silica particles separated to a state close to primary particles adhere to the surface, whereby the flow characteristics of the particle material are improved and the classification efficiency is improved.

  The classification process is not particularly limited. Examples include a method of passing a sieve through a dry method, a method of passing a sieve through a wet method, and air classification. Sieving performed by a dry method is preferable because the operation is simple.

  The method for adhering the silica particles to the surface of the particle material is not particularly limited, and can be carried out by simply mixing or applying vibration after mixing. The silica particles can be attached to the surface of the particulate material in a dry state. The mixing ratio of the particulate material and the silica particles is not particularly limited. Even if the amount is small, if the silica particles are present on the surface of the particle material, it is considered that the effect of improving the flow characteristics by the silica particles can be exhibited. For example, the content of silica particles can adopt the upper limit of about 10%, 5%, and 2% as a preferable range based on the mass of the particle material, and the lower limit of about 0.001%, 0.005%, and 0.01% can be used as a preferable range. .

  The particulate material is composed of an inorganic oxide, and is not particularly limited except that the inorganic oxide alone or the inorganic oxide is a main component (50% or more by mass). The effect of applying the manufacturing method of the present invention is increased because the particle material has a higher cohesion as the particle size is smaller. Therefore, the volume average particle size of the particulate material is desirably 100 μm or less, more desirably 50 μm or less, and even more desirably 10 μm or less.

  The inorganic oxide constituting the particulate material is not particularly limited. Examples thereof include silica, alumina, titania, zirconia, composite oxides and mixtures thereof.

  The particulate material may be surface treated. The surface treatment can be performed with a silane coupling agent, organosilazane or the like. Examples of the silane coupling agent and organosilazane include those described later. The amount of the surface treatment is not particularly limited.

  The raw silica particles have a primary particle volume average particle size of 200 nm or less and a bulk density of 450 g / L or less. And it is desirable that it is 100 g / L or more. As a volume average particle diameter, 100 nm, 70 nm, and 50 nm are mentioned as a preferable upper limit. Moreover, 1 nm is mentioned as a preferable minimum. The raw material silica particles preferably have a particle size of 300 nm 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.

  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 preferably have a functional group containing carbon introduced on the surface. Details will be described later.

  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. 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 (1): -OSiX ¹ X ² X ³ and the formula (2): -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 (1) is referred to as a first functional group, and the functional group represented by the formula (2) 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 included in the first functional group, the number of R included in the first functional group, the number of R included in the second functional group, and the presence ratio between the R and X ^1, raw material 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.

  Since the raw silica particles hardly aggregate, they can be provided as raw silica particles that are not dispersed in a liquid medium such as water or alcohol. In this case, since no liquid medium is brought in, it is preferably used as a filler for a resin material.

  Further, since the raw silica particles are difficult to aggregate, they can be easily washed with water.

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).

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 (1). X ⁴ and X ⁵ are each an alkoxy group. By surface-treating with organosilazane, the third functional group X ⁴ and X ⁵ are derived from organosilazane —OSiY ¹ Y ² Y ³ (the functional group represented by the formula (2), the 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 (1): -OSiX ¹ X ² X ³ (that is, the first functional group) and a formula (2): -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.

  The raw silica particles may be provided with a solidification step after the surface treatment step. The solidification step is a step in which the raw material silica particles after the surface treatment are precipitated with a mineral acid, and the precipitate is washed with water and dried to obtain a solid material of the raw material silica particles. As described above, since general silica particles are very likely to aggregate, it is very difficult to disperse once solidified silica particles. However, since the raw silica particles are difficult to agglomerate, they are difficult to agglomerate even if solidified, and are easily redispersed even if agglomerated. In the washing step, washing is preferably repeated until the electrical conductivity of the extraction water of the raw silica particles (specifically, the water in which the silica particles are immersed at 121 ° C. for 24 hours) is 50 μS / cm or less.

  Examples of the mineral acid used in the solidification step include hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid, and hydrochloric acid is particularly desirable. The mineral acid may be used as it is, but is preferably used as a mineral acid aqueous solution. The concentration of the mineral acid in the aqueous mineral acid solution is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more. The amount of the mineral acid aqueous solution can be about 6 to 12 times based on the mass of the raw silica particles to be cleaned.

  The cleaning with the mineral acid aqueous solution can be performed a plurality of times. The washing with the mineral acid aqueous solution is preferably performed after the raw silica particles are immersed in the mineral acid aqueous solution and then stirred. Further, it can be left in the immersed state for 1 to 24 hours, and further for about 72 hours. When it is allowed to stand, stirring can be continued or not stirred. When washing in the mineral acid-containing liquid, it can be heated to room temperature or higher.

  Thereafter, the raw silica particles washed and suspended are collected by filtration and then washed with water. It is desirable that the water used does not contain ions such as alkali metals (for example, 1 ppm or less on a mass basis). For example, ion exchange water, distilled water, pure water and the like. Washing with water is the same as washing with an aqueous mineral acid solution, after the raw silica particles are dispersed and suspended, they can be filtered, or by continuously passing water through the filtered raw silica particles. Is possible. The end of washing with water may be determined by the electrical conductivity of the extracted water described above, or may be the time when the alkali metal concentration in the waste water after washing the raw silica particles becomes 1 ppm or less, It is good also as the time of the alkali metal concentration of extraction water becoming 5 ppm or less. When washing with water, it can be heated to a room temperature or higher.

  Drying of the raw silica particles can be performed by a conventional method. For example, heating or leaving under reduced pressure (vacuum).

(Classified particle material)
The classified particle material of the present embodiment includes silica particles and a particle material having the silica particles attached to the surface. The silica particles have a primary particle volume average particle size of 200 nm or less and a bulk density of 450 g / L or less. The silica particles have a functional group represented by the formula (1): -OSiX ¹ X ² X ³ and a functional group represented by the formula (2): -OSiY ¹ Y ² Y ³ on the surface. Since these details are the same as the contents explained in the above-mentioned manufacturing method, they are omitted.

The particulate material has a volume average particle size larger than the primary particles of the silica particles, and the silica particles adhere to the surface. It is desirable that 5 or more silica particles are present per ² (300 nm) ^{2 on} the surface of the particle material. Specifically, using a photograph taken with an FE-SEM, 10 regions of 300 nm × 300 nm are randomly selected from the surface of the particle material, and the average value is obtained by counting the number of silica particles present there. Do. Whether or not it is a silica particle of the present embodiment is determined by whether or not the particle exists as a primary particle on the surface of the particle material. Here, the presence of primary particles means particles in a state where the particles are in contact with each other in a SEM photograph.

  The classified particle material preferably has a mode diameter / cut point of 0.56 or more. The mode diameter is the particle diameter showing the largest value when the particle size distribution (volume frequency) is measured, and the cut point means the particle diameter that becomes 99.9% when the volume frequency is integrated from the smaller particle diameter side. To do. A simple method for obtaining the cut point is to prepare an appropriately sized sieve (for example, an opening of 10 μm), find the percentage of particles that could not pass through the sieve, and if the percentage is 0.1% or less You may judge that the opening of the sieve is a cut point. This simple method produces an error in the direction in which the measured value of the cut point becomes higher than the exact value in principle, but the error works in the direction in which the value of the mode diameter / cut point decreases, so the mode diameter / cut point There is no problem in using it for specifying the classified particle material of the present embodiment, which defines that it is desirable that the ratio is large. Here, the value of the mode diameter / cut point is a value related to the precision of classification. The larger this value, the more accurate the classification.

(Resin composition)
The resin composition of this embodiment is a mixture of the classified particle material described above and a resin material (including a resin material precursor). The mixing ratio between the classified particle material and the resin material is not particularly limited. However, the larger the amount of the classified particle material, the better the thermal stability. Furthermore, as the classified particle material has a higher sphericity, the filling property into the resin material or the like can be improved.

  The resin material or the like is a composition that can be cured under some conditions. For example, a mixture of a prepolymer and a curing agent. The curing agent may be mixed immediately before curing. The type of resin material is not particularly limited. For example, it is desirable to have an epoxy group, oxetane group, hydroxyl group, blocked isocyanate group, amino group, half ester group, amic group, carboxy group and carbon-carbon double bond group in the chemical structure. These functional groups are functional groups (polymerizable functional groups) that can be bonded to each other by setting suitable reaction conditions, and resin materials and the like can be cured by selecting appropriate reaction conditions. Suitable reaction conditions for curing include simple heating and light irradiation, generation of reactive species such as radicals and ions (anions and cations) by heat and light irradiation, and bonding between these functional groups. For example, adding a reaction initiator (polymerization initiator) to perform heating or light irradiation. A compound necessary for the polymerization reaction can be added as a curing agent, or a catalyst for the reaction can be added.

  Preferred examples of the resin material include a monomer that forms a polymer material by polymerization and a polymer material modified with a polymerizable functional group as described above. For example, a prepolymer such as an epoxy resin, an acrylic resin, or a urethane resin before curing is suitable. In particular, when the thermal stability is high, it is desirable that the composition is composed mainly of an epoxy resin.

  The manufacturing method of the classified particle material of this invention is demonstrated based on an Example. In this example, when mentioning the particle size, the particle size of the secondary particles is described unless there is a description that the particle size of the primary particles.

[Test Example 1]
(Manufacture of silica particles)
-Production of raw silica particles Colloidal silica snowtex OS (silica content 20%: manufactured by Nissan Chemical Industries, Ltd .: primary particle size is 10 nm) as 100 parts by weight as an aqueous slurry in which silica particles are dispersed in water as an aqueous medium The pretreatment process (surface treatment process and drying process) was performed.

(Surface treatment process)
(1) Preparatory process 40 mass parts of isopropanol was added to 100 mass parts of aqueous slurry, and the dispersion liquid by which a silica particle was disperse | distributed to the liquid medium was obtained by mixing at room temperature (about 25 degreeC).
(2) First Step 1.82 parts by mass of phenyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM103) was added to this dispersion and mixed at 40 ° C. for 72 hours. By this step, the hydroxyl group present on the surface of the silica particles was surface treated with a silane coupling agent. At this time, phenyltrimethoxysilane was calculated and added so that a necessary amount of hydroxyl groups (partially) remained without being surface-treated.
(3) Second Step Next, 3.71 parts by mass of hexamethyldisilazane was added to this mixture and left at 40 ° C. for 72 hours. Through this step, the silica particles were surface-treated to obtain a silica particle material. As the surface treatment progressed, the silica particles that became hydrophobic could no longer exist stably in water and isopropanol, and agglomerated and precipitated. The molar ratio of phenyltrimethoxysilane to mexamethyldisilazane was 2: 5.

(Solidification process)
4.8 parts by mass of 35% aqueous hydrochloric acid solution was added to the mixture obtained in the surface treatment step to precipitate the silica particle material. The precipitate was filtered with a filter paper (5A manufactured by Advantech). The filtration residue (solid content) was washed with pure water and then vacuum-dried at 100 ° C. to obtain a silica particle material solid material (raw material silica particles).

  The obtained silica particles had D10 of 8.8 μm, D50 of 124.5 μm, and D90 of 451.9 μm.

(Crushing process)
A crushing step was performed on the obtained raw material silica particles to obtain silica particles of this test example. The crushing step was carried out under the conditions of a crushing pressure of 0.3 MPa and a supply rate of 10 kg / h using a jet mill (manufactured by Seishin Enterprise Co., Ltd., model number STJ-200). The obtained silica particles had a bulk density of 251.7 g / L, D10 of 0.8 μm, D50 of 1.8 μm, D90 of 4.0 μm, and primary particles having a volume average particle size of 10 nm.

(Evaluation 1: Screening of silica particles)
The obtained silica particles of Test Example 1 were shaken in a mixture of 0.5 parts by mass and 100 parts by mass of spherical silica particles having a volume average particle diameter of 6 μm (hereinafter simply referred to as “spherical silica particles” manufactured by Admatex). Using a machine (Yamato Scientific Co., Ltd .: SA300), the sample was shaken at 250 rpm for 1 minute to obtain a test sample of this test example. As a control, spherical silica particles alone were prepared without adding the silica particles of the test example. When the tactile sensation was examined for these, the test sample of Test Example 1 was much smoother than the control test sample, and the test sample of Test Example 1 was self-supporting when the powder was put in a bag. Then I couldn't stand alone.

  The test sample was passed through a sieve and the particle size distribution was measured. The results are shown in FIGS. 1 to 4 (FIG. 1: 10 μm, FIG. 2: 15 μm, FIG. 3: 20 μm, FIG. 4: 25 μm. The black circle is the test sample of Test Example 1 and the white circle is the control test sample). D50, D75, and D100 shown in FIGS. 1 to 4 integrate the volume of the particles from the smaller particle size, and are 50% (D50), 75% (D75), and 100% (D100) based on the whole. This is the particle size. The mode diameter is the most frequently used particle diameter. In each figure, the values written on the left side of D50, mode diameter, D75, and D100 are those obtained by sorting the test sample of Test Example 1 on the left side of the drawing, and those obtained by sieving the spherical silica particles alone on the right side. is there.

  As is clear from the figure, the test sample of Test Example 1 has a larger particle size as a whole, and the frequency changes abruptly with the particle size in the vicinity of the opening diameter of the sieve (that is, the accuracy of separation is higher). I found that it was expensive. In addition, Table 1 shows the results of measuring the yield and the passing speed of the sieve when passing through a sieve of 15 μm and 25 μm.

  As is clear from the table, it was found that the efficiency of sieving was improved by adding the silica particles of Test Example 1.

(Evaluation 2: About cut points)
Using the fused silica (manufactured by Admatechs, volume average particle size described in the table, surface treatment with HMDS) and the test sample 1 as the particulate material, and the combinations shown in Table 2, they were mixed. The mixing ratio was 0.5% when the test sample 1 was mixed. The mixture was shaken at 250 rpm for 1 minute using a shaker (Yamato Scientific Co., Ltd .: SA300). Then, classification was performed by the method in the table with a predetermined diameter (described as a cut point in Table 2). The classification and the mixture after classification (classified particle material) were evaluated, and the results are shown in Table 2.

The particle size distribution was measured with a laser diffraction / scattering particle size distribution measuring device (LA500, manufactured by Horiba, Ltd.). The average particle diameter (volume average particle diameter), mode diameter, and D90 (90% cumulative particle diameter) were calculated from the measured particle size distribution. The absence of particles having a particle size equal to or greater than the cut point was confirmed as follows. First, 10 g of a sample is weighed and mixed with 90 g of solvent (water). The mixture was lightly shaken and then subjected to ultrasonic irradiation for 20 minutes. The dispersion was poured into a sieve having an opening corresponding to the cut point. The sieve was directly irradiated with ultrasonic waves to remove aggregates. By collecting the particulate material remaining on the sieve and measuring the mass, the existence ratio of the particulate material having a particle diameter equal to or larger than the cut point can be calculated. It was confirmed that the value was 0.1% or less. Various values shown in Table 2 were calculated from the obtained values. Here, “circularity” in this specification means S E M
Then, from the observed particle area and perimeter, the value is calculated as (circularity) = {4π × (area) ÷ (perimeter) ² }. The closer to 1, the closer to a perfect circle. Specifically, an average value measured for 100 particles using an image processing apparatus (Sysmex Corporation: FPIA-3000) is employed. It is considered that the higher the circularity, the higher the fluidity.

  As is clear from the table, it was found that when dry sieves were used (samples 1 to 5 in Table 2), the addition of silica particles improved the yield and increased the value of mode diameter / cut point. . Here, even when silica particles were added, neither yield nor mode diameter / cut point values were sufficient when using air classification (Sample 6 in Table 2). In addition, when wet sieving was performed, the mode diameter / cut point value was sufficient, but the yield was not sufficient (Sample 7 in Table 2). In summary, it was found that both the mode diameter / cut point value and the yield were sufficient by adding silica particles and classifying with a dry sieve.

(Evaluation of silica particle adhesion)
Using a shaker (Yamato Scientific Co., Ltd .: SA300), a mixture obtained by mixing 0.33 parts by mass of test sample 1 with 100 parts by mass of particles (silica) having a volume average particle size of 0.5 μm, at 250 rpm for 1 minute. Shake (mixture A).

  Using a shaker (Yamato Scientific Co., Ltd .: SA300), which is a mixture of 0.25 parts by mass of test sample 1 with 100 parts by mass of particles (silica) having a volume average particle size of 1.5 μm, at 250 rpm for 1 minute. Shake (mixture B).

The FE-SEM photograph of each obtained mixture is shown in FIG. 5 (mixture A) and FIG. 6 (mixture B). From the figure, the average value of the amount of silica particles (test sample 1) adhering per unit area (300 nm square) was calculated. Result, mixture A in 5 / (300 ^{nm) 2,} was a mixture in B 6 pieces / ^{(300nm) 2.}

It is clear that the fluidity is improved in both the mixture A and B before the test sample 1 is added, and the effect is ensured by attaching silica particles to the surface at a density of 5 particles / (300 nm) ² or more. It was found that can be expressed.

[Test Examples 2 to 4]
In the crushing step in Test Example 1, the bulk density was adjusted by adjusting the crushing pressure and the supply amount. The bulk density of the test sample of Test Example 2 was 271.3 g / L, the test sample of Test Example 3 was 364.6 g / L, and the test sample of Test Example 4 was 249.8 g / L. There was a tendency for the bulk density to increase by increasing the crushing pressure. Although the detailed results are not shown in the following table, it has been clarified that the same effect as the test sample of Test Example 1 is exhibited by performing the same test as the following evaluation test.

Claims (9)

For raw material silica particles having a volume average particle size of primary particles of 200 nm or less,
Has a crushing step of performing crushing until the bulk density is determined that Tsu name below 450 g / L (except the conditions for grinding the primary particles),
The silica particles obtained in the crushing step and the particle material made of an inorganic oxide having a volume average particle size larger than the primary particles of the silica particles are mixed to adhere the silica particles to the surface of the particle material. Mixing step to make silica-coated particle material;
A classification step of classifying the silica-coated particle material with a dry sieve;
Have
The raw silica particles are
A surface treatment step of surface treatment with a silane coupling agent and an organosilazane in a liquid medium containing water;
Removing the liquid medium;
It is processed in the pretreatment process with
The silane coupling agent has three alkoxy groups, 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,
The molar ratio of the silane coupling agent to the organosilazane is the silane coupling agent: the organosilazane = 1: 2 to 1:10.
A method for producing a classified particulate material. The surface treatment step includes
A first treatment step of treating with the silane coupling agent;
A second treatment step of treating with the organosilazane,
The method for producing a classified particulate material according to claim 1, wherein the second treatment step is performed after the first treatment step.   The method for producing a classified particle material according to claim 1 or 2, wherein the particle material is surface-treated with a silane coupling agent and / or an organosilazane. The method for producing a classified particle material according to any one of claims 1 to 3, wherein there are five or more silica particles per (300 nm) ^{2 on} the surface of the particle material. Silica particles having a primary particle volume average particle size of 200 nm or less and a bulk density of 450 g / L or less;
A particle material made of an inorganic oxide having a volume average particle size larger than the primary particles of the silica particles and the silica particles adhering to the surface;
The silica particles include a functional group represented by the formula (1): -OSiX ¹ X ² X ³ and a formula (2):-
OSiY Chi to ¹ Y ² Y ³ in the surface and a functional group represented by a hydroxyl group is substantially absent on the surface,
Classified particle material. (In the above formulas (1) and (2); X ¹ is 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; 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 classified particle material according to claim 5, wherein the particle material is surface-treated with a silane coupling agent and / or an organosilazane. The classified particle material according to claim 5 or 6, wherein there are 5 or more silica particles per ² (300 nm) ^{2 on} the surface of the particle material.   The classified particle material according to any one of claims 5 to 7, wherein the mode diameter / cut point is 0.56 or more. The classified particulate material according to any one of claims 5 to 8,
A resin composition having a resin material in which the classified particle material is dispersed.