JP2010254511A - Basic metallic silicon powder, method for producing the same and highly heat-conductive resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a basic metallic silicon powder which are excellent in the operability in powder handling such as transportation and classification. <P>SOLUTION: The basic metallic silicon powders have metallic silicon powders and a basic substance contacting with the surfaces of the metallic silicon powders so as to have a basic equivalent of 0.1 μmol or more and 10 μmol or less per 1 m<SP>2</SP>of surface area. It is considered that an effect by a mutual action between silica and the basic substance basing on the existence of a minimal oxide (silica) layer on the surfaces of the metallic silicon powders is obtained, that is supported by that an effect by enhancing powder handling is little even when the basic substance is contacted just after the metallic silicon powders are produced by pulverizing pure metallic silicon, that is, it is considered to be enough to react with the basic substance even if the oxide layer existing on the surfaces of the metallic silicon powders is in a trace amount. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a basic metal silicon powder, a method for producing the same, and a high thermal conductive resin composition.

  When sealing or fixing an electronic component or fixing a mechanical component, the resin composition may be used. In that case, in order to provide high thermal conductivity, a resin composition in which metal fine powder is mixed may be employed. In this case, the metal fine powder to be mixed can be exemplified by metal silicon and the particle size is on the order of μm.

JP 2004-161900 A

  When such a fine metal silicon powder is mixed in a resin, the handling becomes a problem. Not only metal silicon powder but also fine powder is agglomerated and the like, and it cannot be said that its handling is good unless any measures are taken.

  Similar problems existed in silica fine particles. Improvement of physical properties such as thermal stability can be expected by mixing silica fine particles in a resin to obtain a resin composition. Patent Document 1 discloses a silica powder whose surface is treated with a basic substance.

  The present invention has been completed in view of the above circumstances, and a basic metal silicon powder, which is a metal silicon powder excellent in operability of powder operations such as powder transportation and classification, a method for producing the same, and high thermal conductivity Providing a resin composition is a problem to be solved.

  In the method described in Patent Document 1, oxygen atoms (and silicon atoms) present on the surface of silica fine particles interact with the basic substance, so that the basic substance can be stably attached to the surface. It is considered to be. In other words, the stable presence of the basic substance causes the powders to repel each other due to electrostatic repulsion, and as a result, aggregation of the powder is effectively suppressed. Therefore, it seems that there is no effect even if the method of Patent Document 1 is applied to metal silicon powder that can be regarded as having substantially no oxygen atoms on the surface.

  However, as a result of intensive investigations aimed at solving the above-mentioned problems, the present inventors have unexpectedly achieved an unexpected effect that improvement in powder operation is recognized for metal silicon powder by the same method as in Patent Document 1. I found it. Inferring this reason, it is considered that the same effect as in Patent Document 1 can be obtained by the presence of a slight oxide (silica) layer on the surface of the metal silicon powder. This is supported by the fact that the effect of improving the operability of the powder is low even if a basic substance is brought into contact immediately after the metal silicon powder is produced by crushing pure metal silicon. That is, it is considered that even a trace oxide layer present on the surface of the metal silicon powder is sufficient to react with the basic substance. The present invention has been completed based on these findings.

That is, the characteristics of the basic metal silicon powder according to claim 1 for solving the above-described problems are:
And having a basic substance brought into contact with the surface of the metal silicon powder so as to have a base equivalent of 0.1 μmol or more and 10 μmol or less per 1 m ^{2 of} surface area.

  A feature of the basic metal silicon powder according to claim 2 that solves the above problem is that, in claim 1, the basic substance is a compound having an amino group or an imino group, or ammonia.

  A feature of the basic metal silicon powder according to claim 3 for solving the above-mentioned problem is that in claim 1 or 2, the basic substance is a silazane.

  A feature of the basic metal silicon powder according to claim 4 for solving the above-mentioned problem is that, in claim 3, the basic substance is hexamethyldisilazane.

  The basic metal silicon powder according to claim 5 that solves the above problem is characterized in that, in claim 3 or 4, an amount of 10% by mass based on the total mass is suspended in pure water for 10 minutes. After stirring, 90% or more is floating based on the mass of the solid matter. Here, stirring is performed with a shaker (manufactured by Yamato, model number: Shaker SA300).

  A feature of the basic metal silicon powder according to claim 6 for solving the above-mentioned problem is that, in any one of claims 1 to 5, the metal silicon powder is manufactured by crushing.

  The feature of the basic metal silicon powder according to claim 7 for solving the above problem is that, in any one of claims 1 to 6, the volume average particle size of the metal silicon powder is 1 μm to 30 μm. is there.

  The feature of the basic metal silicon powder according to claim 8 that solves the above-mentioned problem is that, in any one of claims 1 to 7, substantially no coarse particles having a particle size of 45 μm or more are contained. .

The basic metal silicon powder production method according to claim 9 for solving the above-mentioned problems is characterized in that the metal silicon powder has a base equivalent of 0.1 μmol or more and 10 μmol or less per 1 m ^{2 of} surface area. The object is to have a surface treatment step of bringing a basic substance into contact with the powder surface.

The characteristic of the high thermal conductive resin composition according to claim 10 that solves the above problem is that the basic metal silicon powder according to any one of claims 1 to 8,
And an organic resin in which the basic metal silicon powder is dispersed.

  According to the basic metal silicon powder according to claims 1 to 8, the fluidity is excellent, the powder operability such as classification and transportation is excellent, and the bulk property is metal silicon itself, so that high heat The effect that the original performance of metal silicon powder such as conductivity and high electrical conductivity is not impaired is produced. In particular, the effect is further improved by employing the basic substance used in the basic metal silicon powder according to claims 2 to 4. Further, by having properties such as the basic metal silicon powder according to claim 5, higher performance can be exhibited. Further, by not containing coarse particles substantially like the basic metal silicon powder according to claim 8, it is possible to maintain high performance such as permeability.

  According to the manufacturing method of the basic metal silicon powder according to the ninth aspect, the basic metal silicon powder according to the first to eighth aspects can be effectively manufactured.

  Since the resin composition according to claim 10 is filled with the basic metal silicon powder of the present invention described above, the resin is filled with the basic metal silicon powder at a high density and has excellent thermal conductivity. A composition can be provided.

It is the graph shown about the HMDS contact amount dependence of the transmittance | permeability of the sieve of 45 micrometers of openings in an Example.

  The basic metal silicon powder of the present invention and the production method thereof will be described in detail below based on the embodiments. The basic metal silicon powder of the present embodiment is one in which a basic substance reacts or adheres to the surface of a powder made of metal silicon. Since most of it is metallic silicon, its application is almost the same as that of pure metallic silicon powder. For example, it can be used as a raw material for producing silica fine particles by combustion by dispersing in a resin or by combustion. The particle diameter of the basic metal silicon powder of the present embodiment is not particularly limited, but the basic metal silicon powder of the present embodiment is excellent in operability of classification operation, so that the desired particle size distribution can be easily achieved. is there. For example, the volume average particle diameter is desirably 1 μm to 30 μm. Moreover, it is desirable that the coarse particle | grains of 45 micrometers or more are not included substantially.

  The metal silicon powder is not particularly limited. For example, it can manufacture by grind | pulverizing the metallic silicon regardless of a form, or can manufacture it by the atomizing method from the molten metallic silicon. Since the particle size of the metal silicon powder has a high correlation with the particle size of the basic metal silicon powder to be produced, the particle size distribution is obtained so that the necessary particle size is obtained for the basic metal silicon powder of this embodiment. Is adjusted. The particle size distribution can be adjusted by changing the powder production conditions and classifying the obtained powder. Further, at the stage of the metal silicon powder, the particle size distribution is not adjusted by classification or the like, and the classification operation can be performed after the basic metal silicon powder is formed. The purity of the metal silicon powder can be determined according to the purpose for which the basic metal silicon powder is used. If the metal silicon in the basic metal silicon powder is required to have high purity, the metal silicon powder should be of high purity, and if not so pure, the metal silicon powder The purity of is also adopted according to the degree.

  The basic substance is not particularly limited as long as it shows basicity. Here, to show basicity, when the metal silicon powder is treated with silazanes, the pH value of the extracted water of the treated metal silicon powder is pure water or pure water and ethanol, isopropyl alcohol, etc. Compared to the pH of the mixed solvent with alcohols of at least 0. It is preferably 1 or higher. Thereby, it can confirm that metal silicon powder was basified to appropriate quantity. Here, the pH measurement method of the powdered extracted water is as follows. Weigh 3.5 g of powder and place in a plastic container. Add 35 ml of deionized water and extract with an infiltration machine for 30 minutes. Solid-liquid separation is performed with a centrifuge, and the pH of the supernatant water is measured. A specific basic substance is a compound having an amino group or an imino group, or ammonia. For example, silazanes (hexamethyldisilazane (HMDS), hexaphenyldisilazane, etc.) can be mentioned.

A basic substance to make the surface area 1 m ² per 0.1μmol more 10μmol following base equivalent of the metal silicon powder as the amount of contacting the surface of the metal silicon powder. Preferably, it is 0.5 μmol or more, more than 0.5 μmol, or 1 μmol or more per 1 m ² of the surface area of the metal silicon powder. Although it does not specifically limit as an upper limit, 15 micromol or less, less than 15 micromol, 10 micromol or less, less than 10 micromol, 5 micromol or less, and less than 5 micromol are mentioned.

Here, the base equivalent is defined as treatment amount (mass%: based on the mass of metal silicon powder) / {molecular weight of treatment agent (g / mol) × specific surface area (m ² / g)}. Value. The surface area of the metal silicon powder is a value measured by the BET method using nitrogen.

As a method of treating the treating agent, as a method of contacting the surface of the metal silicon powder, a dry treatment method in which a basic substance is brought into contact as it is, or a solution obtained by dissolving a basic substance in some solvent to obtain a solution, A wet processing method in which the powder to be processed is brought into contact, or a powder to be processed made of metal silicon powder is contained in a processing container, and the powder to be processed is reacted with a processing agent vaporized while stirring. In the case where HMDS is adopted as the basic substance, a gas phase reaction method can be adopted. After the basic substance is brought into contact with the surface of the metal silicon powder, the excess basic substance can be removed. For example, it can be removed by immersing and stirring in a solvent (such as water) in which the basic substance can be dissolved. In this case, the basic substance may be removed when the binding state is weak.
Next, the resin composition of the present invention will be described in detail below. The resin composition of the present embodiment has the above basic metal silicon powder and an organic resin in which the basic metal silicon powder is dispersed. The ratio of containing the basic metal silicon powder is not particularly limited, but it is desirable to add an amount that makes contact (point contact) between the basic metal silicon powders in a state where the resin composition is cured. That is, the thermal conductivity can be improved by contacting between the basic metal silicon powders.

  The organic resin is not particularly limited, but epoxy resin, silicone resin, phenol resin, melamine resin, urea resin, unsaturated polyester, fluororesin, polyimide, polyamideimide, polyetherimide and other polyamides, polybutylene terephthalate, polyethylene terephthalate, etc. Polyester, polyphenylene sulfide, wholly aromatic polyester, polysulfone, liquid crystal polymer, polyethersulfone, polycarbonate, maleimide modified resin, ABS resin, AAS (acrylonitrile, acrylic rubber, styrene) resin, AES (acrylonitrile, ethylene, propylene, diene rubber, Examples thereof include thermosetting resins such as (styrene) resin, thermoplastic resins, and various engineering plastics. The organic resin is particularly preferably a curable resin that is cured by a chemical reaction or the like.

  The epoxy resin is not particularly limited, and monomers, oligomers, and polymers generally having two or more epoxy groups in one molecule are used. For example, biphenyl type epoxy resin, stilbene type epoxy resin, bisphenol type epoxy resin, triphenol methane type epoxy resin, alkyl modified triphenol methane type epoxy resin, dicyclopentadiene modified phenol type epoxy resin, naphthol type epoxy resin, triazine core containing An epoxy resin etc. are illustrated. These may be used alone or in combination. Since the inorganic filler is preferably highly filled in the epoxy resin composition, a low-viscosity resin is preferable in order to maintain good fluidity of the epoxy resin composition.

  It does not specifically limit as a phenol resin, The monomer, oligomer, and polymer generally which have two or more phenolic hydroxyl groups in 1 molecule are said. For example, dicyclopentadiene modified phenol resin, phenol aralkyl resin, naphthol aralkyl resin, terpene modified phenol resin, triphenolmethane type resin and the like are exemplified. These may be used alone or in combination. Since the inorganic filler is preferably highly filled in the epoxy resin composition, a low-viscosity resin is preferred in order to maintain good fluidity of the epoxy resin composition.

(Test 1)
A metal silicon powder having a volume average particle diameter of 21.5 μm and a specific surface area of 0.91 m ² / g (BET: N ₂ ) was prepared. This powder was prepared by grinding metal silicon. After pulverization, it was used for 1 day.

  After drying this metal silicon powder, HMDS as a basic substance was brought into contact with the amount shown in Table 1 to obtain a basic metal silicon powder of a test example. Thereafter, 50 g of each sample was weighed, passed through a sieve having an opening of 45 μm, and the mass ratio of the powder that passed through the sieve was measured. The passage of the sieve was performed by supplying the test sample to the sieve while applying vibration and holding it for 5 minutes. The results are shown in FIG.

  As is clear from FIG. 1 and Table 1, untreated metal silicon powder was able to pass only 25% of the total mass through the sieve, whereas in the sample with HMDS in contact with the surface, A larger amount could pass through the sieve. This is considered that the fluidity is improved by suppressing the aggregation of the powder due to the interaction between the metal silicon powders.

The addition of HMDS exhibits a sufficient effect even at 0.5 μmol / m ² , but further effects were observed when 1.0 μmol / m ² or more was added. In addition, when HMDS is added exceeding 3 μmol / m ² , the effect gradually decreases. It is considered that the electrostatic repulsion between particles is increased according to the amount of HMDS. However, it was clear that the permeability of the sieve was improved more than the case where nothing was treated even at 15 μmol / m ² in this experiment.

Claims (10)

Metal silicon powder,
A basic metal silicon powder comprising a basic substance brought into contact with the surface of the metal silicon powder so as to have a base equivalent of 0.1 μmol or more and 10 μmol or less per 1 m ^{2 of} surface area.   The basic metal silicon powder according to claim 1, wherein the basic substance is a compound having an amino group or an imino group, or ammonia.   The basic metal silicon powder according to claim 1 or 2, wherein the basic substance is a silazane.   The basic metal silicon powder according to claim 3, wherein the basic substance is hexamethyldisilazane.   The base according to claim 3 or 4, wherein 10% by mass based on the total mass is suspended in pure water and stirred for 10 minutes, and then 90% or more is suspended based on the mass of solid matter. Metallic silicon powder.   The basic metal silicon powder according to claim 1, wherein the metal silicon powder is produced by crushing.   The basic metal silicon powder according to any one of claims 1 to 6, wherein the volume average particle size of the metal silicon powder is 1 µm to 30 µm.   The basic metal silicon powder according to any one of claims 1 to 7, which does not substantially contain coarse particles having a particle diameter of 45 µm or more. A basic treatment characterized by having a surface treatment step of bringing a basic substance into contact with the surface of the metal silicon powder so as to have a base equivalent of 0.1 μmol or more and 10 μmol or less per 1 m ^{2 of} surface area of the metal silicon powder. Manufacturing method of metal silicon powder. The basic metal silicon powder according to any one of claims 1 to 8,
And an organic resin in which the basic metal silicon powder is dispersed.

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