阅读说明：本技术 硅烷处理镁橄榄石微粒及其有机溶剂分散液、以及它们的制造方法 (Silane-treated forsterite fine particles, organic solvent dispersion thereof, and method for producing same ) 是由 伊左治忠之 飞田将大 于 2015-08-06 设计创作，主要内容包括：硅烷处理镁橄榄石微粒及其有机溶剂分散液、以及它们的制造方法。具有5～100m～(2)/g的比表面积,且每1nm～(2)的表面积结合1～5个甲硅烷基。(Silane-treated forsterite fine particles, an organic solvent dispersion thereof, and a method for producing the same. Has a thickness of 5 to 100m 2 Specific surface area per g, and per 1nm 2 The surface area of (2) is bonded with 1 to 5 silyl groups.)

1. Silane-treated forsterite fine particles characterized by being silane-treated by being formed to have a particle size of 5 to 100m²The forsterite fine particles having a specific surface area/g are wet-pulverized by a bead mill in a dispersion medium containing an organic solvent composed of isopropyl alcohol, and then the forsterite fine particles are mixed with an organic silicon compound andand/or a hydrolysate thereof, wherein the mass ratio of the organosilicon compound to the forsterite fine particles, i.e., the organosilicon compound/forsterite fine particles, is equivalent to 1nm of the forsterite fine particles²The surface area of 1 to 5 silyl groups is mixed at a mass ratio of 1nm to perform silane treatment²The surface area of (2) is bonded with 1 to 5 silyl groups.

2. The silane-treated forsterite fine particles according to claim 1, wherein the silyl group is represented by the following formula (1),

-Si(R¹)_n(X)_3-n (1)

in the formula (1), R¹The calculated dissolution parameter, namely SP value, according to the Fedors' deduction algorithm is 5.5-11.5, R¹Is at least 1 selected from substituted or unsubstituted alkyl, aryl, halogenated alkyl, halogenated aryl, alkenyl, epoxy, (meth) acryloyl, mercapto, amino and cyano, X is at least one of hydroxyl and alkoxy having 1 to 4 carbon atoms, and n is an integer of 0to 3.

3. An organic solvent dispersion of silane-treated forsterite particles, comprising:

the silane-treated forsterite fine particles as claimed in claim 1 or 2, and

a dispersion medium containing an organic solvent.

4. The organic solvent dispersion of silane-treated forsterite fine particles as claimed in claim 3, wherein the SP value, which is a dissolution parameter of the dispersion medium containing an organic solvent, is 8 to 15.

5. The organic solvent dispersion of silane-treated forsterite fine particles according to claim 3 or 4, wherein the organic solvent is at least 1 selected from the group consisting of methanol, ethanol, isopropanol, dimethylformamide, methyl cellosolve, ethyl cellosolve, butyl cellosolve, ethylene glycol, propylene glycol monomethyl ether acetate, 1-pentanol, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl acetate, butyl acetate, toluene, methyl methacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, bisphenol A-type epoxy resin, and bisphenol F-type resin.

6. The organic solvent dispersion of silane-treated forsterite fine particles according to any one of claims 3 to 5, wherein the organic solvent dispersion has a moisture content of 5% by mass or less.

7. Every 1nm²The method for producing an organic solvent dispersion of silane-treated forsterite fine particles having 1 to 5 silyl groups bonded to the surface area of the fine particles, characterized by comprising the following steps (a) and (b), and if necessary, further comprising the following step (c),

(a) the process comprises the following steps: the particle size is 5-100 m by bead milling²A step of obtaining an organic solvent dispersion by wet-pulverizing forsterite fine particles having a specific surface area of/g in a dispersion medium containing an organic solvent composed of isopropyl alcohol,

(b) the process comprises the following steps: the mass ratio of the organosilicon compound to the forsterite fine particles, that is, the mass ratio of the organosilicon compound to the forsterite fine particles is set to be equivalent to 1nm of the forsterite fine particles²A step of adding an organosilicon compound represented by the following formula (2) and/or a hydrolysate thereof to the organic solvent dispersion obtained in the step (a) so that a silyl group represented by the following formula (1) is bonded to the surface of the forsterite fine particles,

(c) the process comprises the following steps: a step of replacing at least a part of the dispersion medium in the organic solvent dispersion liquid obtained in the step (b) with another organic solvent,

Si(R¹)_n(X)_4-n (2)

in the formula (2), R¹The calculated dissolution parameter, namely SP value, according to the Fedors' deduction algorithm is 5.5-11.5, R¹Is selected from substituted or unsubstituted alkyl, aryl, halogenated alkyl, halogenated aryl, alkenyl, epoxyAt least 1 of (meth) acryloyl group, mercapto group, amino group, and cyano group, X is at least one of hydroxyl group and alkoxy group having 1 to 4 carbon atoms, n is an integer of 0to 3,

-Si(R¹)_n(X)_3-n (1)

in the formula (1), R¹X and n are each independently of the aforementioned R¹X and n are the same.

8. The method for producing the silane-treated forsterite fine particles in an organic solvent dispersion according to claim 7, wherein the SP value, which is a dissolution parameter of the other organic solvent, is 8 to 15.

9. The method for producing an organic solvent dispersion of silane-treated forsterite fine particles according to claim 7 or 8, wherein the other organic solvent is at least 1 selected from the group consisting of methanol, ethanol, dimethylformamide, methyl cellosolve, ethyl cellosolve, butyl cellosolve, ethylene glycol, propylene glycol monomethyl ether acetate, 1-pentanol, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl acetate, butyl acetate, toluene, methyl methacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, bisphenol A-type epoxy resin, and bisphenol F-type resin.

10. The method for producing the silane-treated forsterite fine particles as claimed in claim 7 or 8, wherein the water content of the organic solvent dispersion is 5% by mass or less.

11. A process for producing silane-treated forsterite fine particles, which comprises the following steps (A) and (B),

(A) the process comprises the following steps: a step of obtaining an organic solvent dispersion of silane-treated forsterite fine particles by the production method according to claim 7,

(B) the process comprises the following steps: and removing the dispersion medium contained in the organic solvent dispersion liquid.

12. An electric wire coating agent comprising the silane-treated forsterite fine particles according to claim 1 or 2.

13. An insulating coating material comprising the silane-treated forsterite fine particles as claimed in claim 1 or 2.

14. An insulator comprising the silane-treated forsterite fine particles as set forth in claim 1 or 2.

15. A valve member comprising the silane-treated forsterite fine particles as claimed in claim 1 or 2.

16. A circuit member substrate comprising the silane-treated forsterite fine particles as claimed in claim 1 or 2.

17. A package for a semiconductor, comprising the silane-treated forsterite fine particles as claimed in claim 1 or 2.

Technical Field

The present invention relates to silane-treated forsterite fine particles and a method for producing the same, and an organic solvent dispersion of silane-treated forsterite fine particles and a method for producing the same.

Background

Conventionally, as a sealing material for an integrated circuit or the like, a sealing material obtained by filling insulating ceramic (for example, silica) fine particles in a heat-resistant resin such as an epoxy resin has been put to practical use. On the other hand, with the recent high integration and high capacity of integrated circuits, there is a situation in which an insulating material having low dielectric loss particularly in a high frequency region is developed in order to reduce signal loss in the integrated circuits. Here, forsterite (magnesium silicate; Mg)₂SiO₄) Since dielectric loss is small in a high frequency region and high insulation is exhibited, attention is paid to the material as a dielectric ceramic used in a microwave region.

With respect to such forsterite, the following methods are disclosed: mixing Mg (OH)₂Powder or MgO powder and SiO having an average primary particle diameter of 10 μm or less₂Mixing and pulverizing the powder in water, spray-drying the powder with a spray dryer, firing the powder at 1100 ℃, and further wet-pulverizing and spray-drying the powder to obtain MgO-SiO having an average primary particle diameter of 0.05 to 0.15 [ mu ] m₂Oxide-based powder (see, for example, patent document 1). Further, the following method is disclosed: the molar ratio of the magnesium amount to the silicon amount of the magnesium nitrate aqueous solution to the ethyl silicate solution is 2: 1, and the mixed solution thus obtained is thermally decomposed at 900 ℃ by a spray thermal decomposition method to obtain forsterite powder (see, for example, patent document 2). Further, the following method is disclosed: a crystalline hollow body is obtained by forming fine droplets of a solution obtained by dissolving an inorganic material for a hollow body or a precursor material thereof in a liquid medium or a dispersion obtained by dispersing the inorganic material in a liquid medium, and then subjecting the formed fine droplets to a high-temperature atmosphere in which the inorganic material is sintered or melted (see, for example, patent document 3).

Further, a method of hydrophobizing the surface of forsterite by a silicone oil, a silane coupling agent, or the like is also described (for example, see patent document 4).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2003-327470

Patent document 2: japanese patent laid-open publication No. 2003-2640

Patent document 3: japanese laid-open patent publication No. 7-96165

Patent document 4: japanese laid-open patent publication No. 2007-240825

Disclosure of Invention

Problems to be solved by the invention

However, none of patent documents 1 to 3 relate to the dispersion of forsterite fine particles in an organic solvent. That is, for example, in the case of using forsterite fine particles as a filler for an insulating material, from the viewpoint of compatibility between the forsterite fine particles and a heat-resistant resin and a packing density of the forsterite fine particles in the heat-resistant resin, it is strongly required that colloidal particles of forsterite are dispersed in an organic solvent, and for this reason, none of patent documents 1 to 3 can respond to the above-mentioned requirements.

In the examples of patent document 4, a large excess (20 parts by mass) of silicone oil is added to 100 parts by mass of forsterite to perform the hydrophobization treatment. By such a method, the chemical hydrophobization of the forsterite surface cannot be efficiently performed, and the possibility that components derived from the hydrophobization agent undesirably remain in the system is increased. Therefore, it is sometimes difficult to provide a filler that can be suitably used as an insulating material because it hinders the exertion of various properties such as insulating properties.

Such problems are not limited to the filler for the insulating material, but also occur in other applications such as a micro filler (micro filler) for a composite material other than the insulating material, various ceramics, and a translucent decorative material.

The present invention has been made in view of the above circumstances, and an object thereof is to provide silane-treated forsterite fine particles and a method for producing the same, and an organic solvent dispersion of silane-treated forsterite fine particles and a method for producing the same, which are useful for various applications such as various ceramics, translucent decorative materials, and electronic components, and which, when used for electronic components as an example, can be used as an insulating material having low dielectric loss in a high frequency region, and can improve compatibility with a heat-resistant resin such as an epoxy resin and the like and a filling density.

Means for solving the problems

The silane-treated forsterite fine particles according to the present invention for achieving the above object are characterized by having a particle size of 5 to 100m²Specific surface area per g, and per 1nm²1 to 5 silyl groups are bonded to the surface area.

Here, the silyl group is preferably a group represented by the following formula (1).

[ formula 1]

-Si(R¹)_n(X)_3-n (1)

(in the formula, with respect to R¹The calculated dissolution parameter (SP value) according to the Fedors' extrapolation method is 5.5-11.5, R¹Is at least 1 selected from the group consisting of substituted or unsubstituted alkyl, aryl, halogenated alkyl, halogenated aryl, alkenyl, epoxy, (meth) acryloyl, mercapto, amino, and cyano. X is at least one of a hydroxyl group and an alkoxy group having 1 to 4 carbon atoms. n is an integer of 0to 3. )

An organic solvent dispersion of silane-treated forsterite fine particles according to another aspect of the present invention to achieve the above object, comprising the silane-treated forsterite fine particles described in any one of the above aspects and a dispersion medium containing an organic solvent.

The dissolution parameter (SP value) of the organic solvent-containing dispersion medium is preferably 8 to 15.

The organic solvent is preferably selected from the group consisting of methanol (SP value ═ 14.5), ethanol (SP value ═ 12.7), isopropanol (SP value ═ 11.5), dimethylformamide (SP value ═ 12.0), methylcellosolve (SP value ═ 11.4), ethylcellosolve (SP value ═ 9.9), butylcellosolve (SP value ═ 8.9), ethylene glycol (SP value ═ 14.6), propylene glycol monomethyl ether (SP value ═ 10.5), propylene glycol monomethyl ether acetate (SP value ═ 8.7), 1-pentanol (SP value ═ 11.0), methylethylketone (SP value ═ 9.3), methylisobutylketone (SP value ═ 8.3), cyclohexanone (SP value ═ 9.8), ethyl acetate (SP value ═ 9.1), butyl acetate (SP value ═ 8.5), toluene (SP value ═ 8.9), pentaerythritol (SP value ═ 9.9), pentaerythritol (SP) acrylate (SP value ═ 9.9.9), pentaerythritol (SP value) At least 1 of bisphenol a type epoxy resin (SP value of 10.4) and bisphenol F type resin (SP value of 10.8).

The water content of the organic solvent dispersion is preferably 5% by mass or less.

The method for producing an organic solvent dispersion of silane-treated forsterite fine particles according to still another aspect of the present invention to achieve the above object is characterized by comprising the following steps (a) and (b).

(a) The process comprises the following steps: the particle size is 5-100 m by bead milling²And a step wherein forsterite fine particles having a specific surface area/g are wet-pulverized in a dispersion medium containing an organic solvent to obtain an organic solvent dispersion.

(b) The process comprises the following steps: and (b) adding an organosilicon compound represented by the following formula (2) and/or a hydrolysate thereof to the organic solvent dispersion obtained in the step (a) so that the mass ratio of the organosilicon compound to the forsterite fine particles (organosilicon compound/forsterite fine particles) is 0.01 to 0.50, and bonding a silyl group represented by the following formula (1) to the surfaces of the forsterite fine particles.

Si(R¹)_n(X)_4-n (2)

(in the formula (2), with respect to R¹The calculated dissolution parameter (SP value) according to the Fedors' extrapolation method is 5.5-11.5, R¹Is at least 1 selected from the group consisting of substituted or unsubstituted alkyl, aryl, halogenated alkyl, halogenated aryl, alkenyl, epoxy, (meth) acryloyl, mercapto, amino, and cyano. X is at least one of a hydroxyl group and an alkoxy group having 1 to 4 carbon atoms. n is an integer of 0to 3. )

-Si(R¹)_n(X)_3-n (1)

(in the formula (1), R¹X and n are each independently of the aforementioned R¹X and n are the same. )

The dissolution parameter (SP value) of the organic solvent-containing dispersion medium is preferably 8 to 15.

The organic solvent is preferably selected from the group consisting of methanol (SP value ═ 14.5), ethanol (SP value ═ 12.7), isopropanol (SP value ═ 11.5), dimethylformamide (SP value ═ 12.0), methylcellosolve (SP value ═ 11.4), ethylcellosolve (SP value ═ 9.9), butylcellosolve (SP value ═ 8.9), ethylene glycol (SP value ═ 14.6), propylene glycol monomethyl ether (SP value ═ 10.5), propylene glycol monomethyl ether acetate (SP value ═ 8.7), 1-pentanol (SP value ═ 11.0), methylethylketone (SP value ═ 9.3), methylisobutylketone (SP value ═ 8.3), cyclohexanone (SP value ═ 9.8), ethyl acetate (SP value ═ 9.1), butyl acetate (SP value ═ 8.5), toluene (SP value ═ 8.9), pentaerythritol (SP value ═ 9.9), pentaerythritol (SP) acrylate (SP value ═ 9.9.9), pentaerythritol (SP value) At least 1 of bisphenol a type epoxy resin (SP value of 10.4) and bisphenol F type resin (SP value of 10.8).

Preferably, the method further comprises the following step (c).

(c) The process comprises the following steps: replacing at least a part of the dispersion medium in the organic solvent dispersion liquid obtained in the step (b) with another organic solvent.

The water content of the organic solvent dispersion is preferably 5% by mass or less.

A method for producing silane-treated forsterite fine particles, which is still another aspect of the present invention to achieve the above object, includes the following steps (A) and (B).

(A) The process comprises the following steps: a step of obtaining an organic solvent dispersion of silane-treated forsterite fine particles by the production method described in any one of the above.

(B) The process comprises the following steps: and removing the dispersion medium contained in the organic solvent dispersion liquid.

An electric wire coating agent according to still another aspect of the present invention to achieve the above object is characterized by containing the silane-treated forsterite fine particles described above.

An insulating coating material according to still another aspect of the present invention for achieving the above object is characterized by containing the silane-treated forsterite fine particles described above.

An insulator according to still another aspect of the present invention to achieve the above object includes the silane-treated forsterite fine particles described above.

In another aspect of the present invention to achieve the above object, an electron tube member includes the silane-treated forsterite fine particles described above.

In another aspect of the present invention to achieve the above object, a circuit member substrate includes the silane-treated forsterite fine particles.

In another aspect of the present invention for achieving the above object, the package for a semiconductor includes the silane-treated forsterite fine particles described above.

Effects of the invention

According to the present invention, when silane-treated forsterite fine particles or an organic solvent dispersion thereof are used as, for example, a filler for an insulating material, it is possible to improve the compatibility with a heat-resistant resin such as an epoxy resin and the filling density with respect to the heat-resistant resin. Furthermore, the silane-treated forsterite fine particles and the organic solvent dispersion thereof can be preferably used as a high refractive index coating agent, an antireflection agent, and a microfiller for composite materials such as metals, plastics, and ceramics. In addition, when silane-treated forsterite fine particles or an organic solvent dispersion thereof is used for a dielectric ceramic sintered body used in a microwave region, the sintering temperature can be lowered. In particular, by using the glass component in combination, sintering in a low temperature range of 900 ℃ or less, which is capable of being sintered simultaneously with an Ag-based conductor having low electric resistance, is possible, and a low-temperature-sintered substrate having a low dielectric loss tangent (tan δ) can be produced.

Further, according to the present invention, the silane-treated forsterite fine particles and the organic solvent dispersion thereof can be suitably produced, and the silane-treated forsterite fine particles and the organic solvent dispersion thereof are useful for various applications such as various ceramics, translucent decorative materials, and electronic components (more specifically, electric wire coating agents, insulating paints, insulators, electronic pipe components, circuit component substrates, and semiconductor packages), and when used for electronic components as an example, can be used as an insulating material having low dielectric loss in a high frequency region, and can be improved in compatibility with a heat-resistant resin such as an epoxy resin and in packing density. In particular, a composite of the silane-treated forsterite fine particles obtained by the present invention and a heat-resistant resin such as an epoxy resin prepared from the organic solvent dispersion thereof can be suitably used as a material for a printed circuit board of a high-frequency device or an information processing device, such as a satellite broadcasting device. Further, the composite with a heat-resistant resin of the present invention can be applied to a wide range of fields from, for example, a semiconductor package such as a chip carrier and a pin grid array, and a base member such as a resistor, a switch, a capacitor, and a photosensor to a structural member such as an IC socket and a connector. Further, the present invention can be applied to containers such as microwave ovens.

Detailed Description

The silane-treated forsterite fine particles and the method for producing the same, and the organic solvent dispersion of the silane-treated forsterite fine particles and the method for producing the same according to the embodiment of the present invention will be described in detail below. The embodiment described above represents one aspect of the present invention, and may be arbitrarily changed within the scope of the present invention.

The silane-treated forsterite fine particles according to the present embodiment (hereinafter, may be abbreviated as "fine particles according to the present embodiment") have a particle size of 5 to 100m²Specific surface area per g, and per 1nm²The surface area of (2) is bonded with 1 to 5 silyl groups. Such microparticles according to the present embodiment can be produced as follows: predetermined forsterite fine particles are obtained by wet grinding with a bead mill, and the OH groups exposed on the surface of the forsterite fine particles are subjected to silane treatment (hydrophobization treatment).

Forsterite has low dielectric loss in a high-frequency region, is excellent in insulation properties, and is also excellent in dielectric breakdown voltage resistance. Forsterite herein means containing Mg₂SiO₄(magnesium silicate)) In the above-mentioned composition, Mg is added within a range that exhibits the above-mentioned properties as forsterite₂SiO₄The main components are contained in the forsterite described in the present specification. That is, the "forsterite" may contain Mg depending on the use of the fine particles according to the present embodiment, as long as the gist of the present invention is not changed₂SiO₄And other components.

The specific surface area of the fine particles according to the present embodiment is 5 to 100m²(ii) in terms of/g. If the specific surface area is smaller than the above range (the particle diameter is larger), there may be a problem that the properties as fine particles are not exhibited and the dispersion state in the dispersion medium containing the organic solvent cannot be realized. On the other hand, if the specific surface area is larger than the above range (the particle size is small), the amount of silane coupling agent used for silane treatment of the surface thereof increases, which is not practical, and the wet grinding of the forsterite compound requires an excessive amount of labor.

The specific surface area referred to in the present specification is the surface area per unit mass of the silane-treated forsterite particles. Such a specific surface area can be measured by, for example, a nitrogen adsorption method.

The particles according to the present embodiment have a particle size of 1nm²The number of silyl groups bonded to the surface area of (3) is 1 to 5. If the number of bound silyl groups is less than the above range, the surface of the forsterite particles cannot be completely hydrophobized by wet pulverization by bead milling, and the hydrophobization function obtained by silane treatment cannot be exhibited. On the other hand, it is difficult to bond a silyl group having a bonding number larger than the above range to the surface of the forsterite fine particles due to the relationship with the above specific surface area.

Therefore, in the fine particles according to the present embodiment, the particle diameter is 1nm per unit²The number of silyl groups bonded to the surface area of (2) is preferably 1 to 3, more preferably 2 to 3. When the number of bound silyl groups is in the above range, the hydrophobic function obtained by silane treatment can be suitably exhibited. In the subsequent step to be carried out as required, when the organic solvent dispersion of the fine particles according to the present embodiment is obtained, the organic solvent may be usedAnd (4) a treatment of replacing the organic solvent with another organic solvent to further improve the hydrophobicity. In addition, in the comparative example described later, it was confirmed that: if the forsterite fine particles subjected to the hydrophobic treatment, such as the fine particles according to the present embodiment, are not used, the fine particles settle with the lapse of a predetermined time when the organic solvent is replaced, and the dispersed state cannot be maintained.

Such silyl groups can be incorporated by adding a proportion corresponding to that of forsterite particles (i.e., equivalent to every 1 nm)²The surface area of 1 to 5 silyl groups) is efficiently realized by adding a silane coupling agent. Conversely, the addition of a much larger excess of the treatment agent for hydrophobization to the forsterite fine particles is not preferable because the efficiency of the hydrophobization treatment may be reduced by unexpected polymerization of the treatment agents, and components derived from the excess treatment agent may easily remain in the system unnecessarily.

The number of silyl groups bonded in the present specification means the number of silyl groups chemically bonded to the surface of forsterite fine particles. Therefore, for example, the case where the treating agent for hydrophobization is merely physically adsorbed on the surface of the forsterite fine particles is not included in the number of silyl groups bonded as described in the present embodiment. Since such adsorption is likely to occur when a much larger excess of the treatment agent for hydrophobization is added to the forsterite fine particles, it is preferable to use the amount of the treatment agent for hydrophobization per 1nm (equivalent to that for each 1 nm) in the present embodiment²1 to 5 silyl groups on the surface area of the forsterite fine particles) with a silane coupling agent. In addition, each 1nm²The number of bound silyl groups on the surface area of the silane-treated forsterite particles can be measured by, for example, ICP emission spectroscopy or CHN elemental analysis.

Here, in the fine particles according to the present embodiment, the silyl group is represented by the following formula (1).

[ formula 1]

-Si(R¹)_n(X)_3-n (1)

(wherein R is calculated by the extrapolation of Fedors¹The dissolution parameter of (A) is 5.5-11.5, R¹Is selected from substituted or unsubstitutedAt least 1 of alkyl, aryl, halogenated alkyl, halogenated aryl, alkenyl, epoxy, (meth) acryloyl, mercapto, amino, and cyano of (a). X is at least one of a hydroxyl group and an alkoxy group having 1 to 4 carbon atoms. n is an integer of 0to 3. )

In the above formula (1), R¹The dissolution parameter of (A) is 5.5-11.5. The smaller the difference in the dissolution parameters, the greater the solubility tends to be, and by setting the dissolution parameter within the above range, the forsterite fine particles are easily dispersed in a dispersion medium containing an organic solvent.

The solubility parameter (SP value) calculated by the Fedors' extrapolation method is sometimes referred to as a solubility parameter or solubility parameter, and is calculated by the following equation, for example.

Dissolution parameter (δ) ═ Ev/v^1/2＝(ΣΔei/Δvi)^1/2

(Ev: evaporation energy, v: molar volume, Δ ei: evaporation energy of atom or atomic group of component i, Δ vi: molar volume of atom or atomic group of component i.)

The evaporation energy, molar volume of the atoms or groups of atoms used for the calculation of the dissolution parameters can be obtained with reference to r.f. fedors, polym.eng.sci.,14,147 (1974). Of course, values obtained by other methods may be used within a range not changing the gist of the present invention.

In the formula (1), the alkyl group preferably has 1 to 30 carbon atoms, more preferably 1 to 18 carbon atoms, from the viewpoint of solubility in a dispersion medium containing an organic solvent. Specific examples thereof include methyl, ethyl, propyl, isopropyl, hexyl, tert-butyl, sec-butyl, decyl, dodecyl and octadecyl.

In the formula (1), the aryl group is a phenyl group, a naphthyl group or the like. From the viewpoint of solubility in a dispersion medium containing an organic solvent, a phenyl group is preferable.

Such R¹Is a substituted or unsubstituted group. R¹The substituent which may be present is not particularly limited, and examples thereof include a halogen atom (e.g., fluorine atom, chlorine atom, and bromine atom), a hydroxyl group, a mercapto group, a carboxyl group, an epoxy group, and an alkyl group (e.g., methyl group, ethyl group, isopropyl group, and propyl group)These substituents may be further substituted with one or more groups selected from the group consisting of an aryl group (e.g., phenyl group, naphthyl group, etc.), an aromatic heterocyclic group (e.g., furyl group, pyrazolyl group, pyridyl group, etc.), an alkoxy group (e.g., methoxy group, ethoxy group, isopropoxy group, etc.), an aryloxy group (e.g., phenoxy group, etc.), an alkenyl group (e.g., vinyl group, 1-propenyl group, etc.), an acyloxy group (e.g., acetoxy group, acryloyloxy group, methacryloyloxy group, etc.), an alkoxycarbonyl group (e.g., methoxycarbonyl group, ethoxycarbonyl group, etc.), an aryloxycarbonyl group (e.g., phenoxycarbonyl group), a carbamoyl group (e.g., carbamoyl group, N-methylcarbamoyl group, etc.), an acylamino group (e.g., acetylamino group, benzoylamino group, acrylamido group, methacrylamido group, etc.).

In the formula (1), X is a group capable of being hydrolyzed, and is at least one of a hydroxyl group and an alkoxy group having 1 to 4 carbon atoms, for example. Among them, as the alkoxy group, methoxy, ethoxy, propoxy and butoxy groups are exemplified. In the formula (1), n is preferably 1 to 2, and particularly preferably 1.

In such silyl groups, it is not necessary that all silyl groups have the same structure, and a plurality of R groups¹X and n may be different from each other. In the presence of a compound containing a different R¹In the case of (3), R may be determined in consideration of the existence ratio thereof¹The substantial dissolution parameter of (2) is preferably 5.5 to 11.5. Therefore, R is within a range not changing the gist of the present invention¹The substantial dissolution parameter of (a) is 5.5 to 11.5, and R having a dissolution parameter other than 5.5 to 11.5 is allowed to be included¹。

The silane-treated forsterite fine particles described above and the dispersion medium containing an organic solvent are included to form the organic solvent dispersion liquid of silane-treated forsterite according to the present embodiment (hereinafter, may be abbreviated as "organic solvent dispersion liquid according to the present embodiment").

The silane-treated forsterite fine particles used herein may be the fine particles according to the present embodiment. Within the scope of the gist of the present invention, other fine particles may be included according to the use of the organic solvent dispersion liquid according to the present embodiment.

In addition, the dispersion medium containing the organic solvent preferably has a dissolution parameter of 8 to 15. When the dispersion medium is mixed with a heat-resistant resin such as an epoxy resin, it is preferable that the dissolution parameter is close to that of the heat-resistant resin, and by using a dispersion medium having a dissolution parameter in the above range, colloidal particles of forsterite can be easily dispersed in the dispersion medium, and the heat-resistant resin can be suitably filled with the colloidal particles. Therefore, the resin composition can be easily used for various applications such as a microfiller for composite materials, various ceramics, and a translucent decorative material, and is particularly advantageous for applications as a filler for insulating materials.

Examples of the organic solvent having a dissolution parameter of 8 to 15 include methanol (SP value ═ 14.5), ethanol (SP value ═ 12.7), isopropanol (SP value ═ 11.5), dimethylformamide (SP value ═ 12.0), methylcellosolve (SP value ═ 11.4), ethylcellosolve (SP value ═ 9.9), butylcellosolve (SP value ═ 8.9), ethylene glycol (SP value ═ 14.6), propylene glycol monomethyl ether (SP value ═ 10.5), propylene glycol monomethyl ether acetate (SP value ═ 8.7), 1-pentanol (SP value ═ 11.0), methylethylketone (SP value ═ 9.3), methylisobutylketone (SP value ═ 8.3), cyclohexanone (SP value ═ 9.8), ethyl acetate (SP value ═ 9.1), butyl acetate (SP value ═ 8.5), pentaerythritol (SP value ═ 9.9), pentaerythritol (SP) methacrylate (SP value ═ 9.9), pentaerythritol (SP value ═ 9.9 ═ 9), pentaerythritol (SP value ═ 9.9.9 ═ 9) Bisphenol a type epoxy resins (SP value of 10.4), and bisphenol F type resins (SP value of 10.8). However, the organic solvent is not limited to the above examples, and 1 kind may be used alone, or 2 or more kinds may be used in combination.

The dispersion medium may contain water. Examples of the water include pure water such as ion-exchanged water, ultrafiltration water, reverse osmosis water, and distilled water, and ultrapure water. Such water can be appropriately selected depending on the use of the organic solvent dispersion liquid according to the present embodiment, and for example, pure water or ultrapure water with few impurities can be particularly preferably used in the case of producing a high-purity organic solvent dispersion liquid for electronic materials. However, the water is not limited to the above examples, and 1 kind of water may be used alone, or 2 or more kinds of water may be used in combination.

The water content of the organic solvent dispersion liquid according to the present embodiment is preferably 5% by mass or less. When the water content is within the above range, the solubility in the heat-resistant resin is not impaired, and therefore, the water-soluble resin can be suitably mixed with a heat-resistant resin such as an epoxy resin.

The organic solvent dispersion according to the present embodiment is 0.1 to 50% by mass, preferably 1 to 30% by mass, based on the total metal oxide content of the silane-treated forsterite fine particles. If the ratio of the organic solvent dispersion to the total of all the metal oxides is larger than the above range, the dispersion medium is dispersed in forsterite (Mg)₂SiO₄) On the other hand, if the ratio of the organic solvent dispersion to the total of all the metal oxides is smaller than the above range, the dispersion medium is excessive with respect to forsterite (Mg)₂SiO₄) The state is insufficient. If the organic solvent dispersion liquid is in such an excess state or in such a deficiency state, the function of the present invention is difficult to be effectively exhibited depending on the application of the organic solvent dispersion liquid according to the present embodiment. However, the metal oxide composition is not limited to the above examples, and may be, for example, more than 50% by mass based on the total of all metal oxides, if necessary.

Next, a method for producing fine particles according to the present embodiment and a method for producing an organic solvent dispersion according to the present embodiment will be described.

The method for producing an organic solvent dispersion according to the present embodiment includes the following steps (a) and (b).

(a) The process comprises the following steps: the specific surface area is 5-100 m by bead milling²And a step wherein the forsterite fine particles are wet-pulverized in a dispersion medium containing an organic solvent to obtain an organic solvent dispersion.

(b) The process comprises the following steps: and (b) adding an organosilicon compound represented by the following formula (2) and/or a hydrolysate thereof to the organic solvent dispersion obtained in the step (a) so that the mass ratio of the organosilicon compound to the forsterite fine particles (organosilicon compound/forsterite fine particles) is 0.01 to 0.50, and bonding a silyl group represented by the following formula (1) to the surfaces of the forsterite fine particles.

Si(R¹)_n(X)_4-n (2)

(in the formula (2), R calculated by the Fedors' extrapolation method¹The dissolution parameter (SP value) of (A) is 5.5 to 11.5, R¹Is at least 1 selected from substituted or unsubstituted alkyl, aryl, halogenated alkyl, halogenated aryl, alkenyl, epoxy, (meth) acryloyl, mercapto, amino and cyano, and X is at least one of hydroxyl and alkoxy having 1 to 4 carbon atoms. n is an integer of 0to 3. )

-Si(R¹)_n(X)_3-n (1)

(in the formula (1), R¹X and n are each independently of the aforementioned R¹X and n are the same. )

In the step (a), the thickness of the film is 5 to 100m²The forsterite fine particles themselves having a specific surface area/g can be obtained by a known method such as a solid phase method or a spray pyrolysis method. Of course, the forsterite fine particles may be obtained by other methods.

The dispersion medium containing an organic solvent may use those already described above. The apparatus used for wet grinding by bead milling (hereinafter, sometimes referred to as "bead milling treatment") is not particularly limited, and a known method, such as a ball mill, a sand mill, or a continuous bead mill, may be used.

The concentration of the forsterite fine particles in the bead-milling treatment is preferably 1 to 80% by mass, more preferably 10 to 50% by mass. Thus, the surface of the forsterite fine particles can be efficiently subjected to silane treatment (hydrophobization treatment) in the subsequent step. However, the concentration of the forsterite fine particles in the bead milling treatment is not limited to the above-described examples.

In the step (b), examples of the compound (organosilicon compound) represented by the above formula (2) include tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetraisopropoxysilane, tetra-n-butoxysilane, tetraacetoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriacetoxysilane, methyltributoxysilane, methyltripropoxysilane, methyltripentoxysilane, methyltriphenoxysilane, methyltribenzyloxysilane, methyltriphenoxysilane, cyclotrienyloxysilane, and cyclotriethoxysilaneOxypropoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane, alpha-glycidoxyethyltrimethoxysilane, alpha-glycidoxyethyltriethoxysilane, alpha 0-glycidoxyethyltrimethoxysilane, alpha 3-glycidoxyethyltriethoxysilane, beta 0-glycidoxypropyltrimethoxysilane, beta 1-glycidoxypropyltriethoxysilane, alpha 4-glycidoxypropyltrimethoxysilane, alpha 5-glycidoxypropyltriethoxysilane, gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltriethoxysilane, gamma-glycidoxypropyltripropoxysilane, gamma-glycidoxypropyltributoxysilane, gamma-glycidoxypropyltriphenoxysilane, glycidoxypropyltrimethoxysilane, glycidoxypropyltriethoxysilane, glycidoxypropyltrimethoxysilane, styrene, beta 4-glycidoxybutyltrimethoxysilane, beta 5-glycidoxybutyltrimethoxysilane, alpha 6-glycidoxybutyltriethoxysilane, gamma-glycidoxybutyltrimethoxysilane, alpha 1-glycidoxybutyltrimethoxysilane, alpha 2-glycidoxybutyltriethoxysilane, (3, 4-epoxycyclohexyl) methyltrimethoxysilane, (3, 4-epoxycyclohexyl) methyltriethoxysilane, alpha 7- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, beta- (3, 4-epoxycyclohexyl) ethyltriethoxysilane, beta 2- (3, 4-epoxycyclohexyl) ethyltripropoxysilane, beta 3- (3, 4-epoxycyclohexyl) ethyltributoxysilane,. beta.6- (3, 4-epoxycyclohexyl) ethyltriphenoxysilane,. gamma. - (3, 4-epoxycyclohexyl) propyltrimethoxysilane,. gamma. - (3, 4-epoxycyclohexyl) propyltriethoxysilane,. alpha.8- (3, 4-epoxycyclohexyl) butyltrimethoxysilane,. alpha.9- (3, 4-epoxycyclohexyl) butyltriethoxysilane, glycidoxymethylmethyldimethoxysilane, glycidoxymethylmethyldiethoxysilane,. alpha. -glycidoxyethylmethyldimethoxysilane,. alpha. -glycidoxyethylmethyldiethoxysilane,. beta.7-glycidoxyethylmethyldimethoxysilane,. beta. -glycidoxyethyldimethoxysilane, Alpha-glycidoxypropylmethyldimethoxysilane, alpha-glycidoxypropylmethyldiethoxysilane, beta-glycidoxypropylmethyldimethoxysilane, beta-glycidoxypropylethyldimethoxysilane, and gamma-epoxypropyldimethoxysilanePropoxypropylmethyldimethoxysilane, gamma-glycidoxypropylmethyldiethoxysilane, gamma-glycidoxypropylmethyldipropoxysilane, gamma-glycidoxypropylmethyldibutoxysilane, gamma-glycidoxypropylmethyldiphenoxysilane, gamma-glycidoxypropylethyldimethoxysilane, gamma-glycidoxypropylethyldiethoxysilane, gamma-glycidoxypropylvinyldimethoxysilane, gamma-glycidoxypropylvinyldiethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, gamma-chloropropyltrimethoxysilane, gamma-glycidoxypropylmethyldiethoxysilane, gamma-glycidoxypropylmethyldibutoxysilane, gamma-glycidoxypropylmethyldiphenyltrimethoxysilane, gamma-glycidoxypropylethyltriethoxysilane, glycidoxypropylethyltrimethoxysilane, glycidoxypropylethyltriethoxysilane, glycidoxypropylethyltrimethoxysilane, glycidoxypropylethyltriethoxysilane, glycidoxypropyltriethoxysilane, glycidoxypropylethyltrimethoxysilane, glycidoxypropyltriethoxysilane, glycidoxypropylmethyldimethoxysilane, glycidoxypropyltrimethoxysilane, glycidoxypropyltriethoxysilane, glycidoxypropylmethyldimethoxysilane, glycidoxypropyl-methyldimethoxysilane, and/, Gamma-chloropropyltriethoxysilane, 3,3, 3-trifluoropropyltrimethoxysilane, gamma-methacryloxypropyltrimethoxysilane, gamma-mercaptopropyltrimethoxysilane, gamma-mercaptopropyltriethoxysilane, beta-cyanoethyltriethoxysilane, chloromethyltrimethoxysilane, chloromethyltriethoxysilane, N- (beta-aminoethyl) gamma-aminopropyltrimethoxysilane, N- (beta-aminoethyl) gamma-aminopropylmethyldimethoxysilane, N- (beta-aminoethyl) gamma-aminopropyltriethoxysilane, N- (beta-aminoethyl) gamma-aminopropylmethyldiethoxysilane, gamma-methacryloxypropyltrimethoxysilane, gamma-beta-methacryloxypropyltrimethoxysilane, gamma-methacryloxypropyltrimethoxysilane, gamma-beta-aminoethyltrimethoxysilane, gamma-beta-aminoethyltrimethoxysilane, gamma-aminoethyltriethoxysilane, gamma-beta-aminoethyltrimethoxysilane, gamma-beta-aminoethyltriethoxysilane, gamma-beta-aminoethyltriethoxysilane, gamma-beta-aminoethylgamma-beta-aminoethyltriethoxysilane, gamma-aminoethylgamma-beta-aminoethyltriethoxysilane, gamma-beta-aminoethylgamma-beta-aminoethyltriethoxysilane, gamma-aminoethylgamma-aminoethyltriethoxysilane, gamma-aminoethylgamma-beta-aminoethylgamma-, Dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxysilane, phenylmethyldiethoxysilane, γ -chloropropylmethyldimethoxysilane, γ -chloropropylmethyldiethoxysilane, dimethyldiacetoxysilane, γ -methacryloxypropylmethyldimethoxysilane, γ -methacryloxypropylmethyldiethoxysilane, γ -mercaptopropylmethyldimethoxysilane, γ -mercaptomethyldiethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, etc. Particularly preferred is methyltrimethoxysilane (in the above formula (1), R¹SP value of (5.8), phenyltrimethoxysilane (in the above formula (1), R¹SP value of (2) (10.3), methyltriethoxysilane (in the above formula (1), R¹SP value of(5.8)), methacryloxypropyltrimethoxysilane (in the above formula (1), R¹SP value of (9.5), aminopropyltrimethoxysilane (in the above formula (1), R¹SP value of 9.9).

Further, as the compound represented by the above formula (2) (hydrolysate of organic silicon compound), the above exemplified hydrolysate of organic silicon compound can be also exemplified. Particularly preferred are a hydrolysate of methyltrimethoxysilane, a hydrolysate of phenyltrimethoxysilane, a hydrolysate of methyltriethoxysilane, and a hydrolysate of methacryloxypropyltrimethoxysilane. The hydrolyzate of the organosilicon compound is R in the above formula (2)¹And a compound in which a part or all of X is replaced by a hydrogen atom. Such hydrolysis of the organosilicon compound can be achieved by adding water to the organosilicon compound or, if desired, an acidic aqueous solution of an aqueous hydrochloric acid solution, an aqueous sulfuric acid solution, or an aqueous acetic acid solution.

The organic silicon compounds represented by the above formula (2) and the hydrolysate thereof may be used alone in 1 kind, or may be used in combination in 2 or more kinds. It is also possible to use the organosilicon compounds and their hydrolyzates in combination.

The compound of the formula (2) used in the step (b) is exemplified by adding the compound of the formula (2) to the hydrophilic organic solvent dispersion of forsterite fine particles obtained in the step (a) and aging the mixture to bond the silyl group of the formula (1) to the surface of the forsterite fine particles (hydrophobization treatment), as described above. By performing such a hydrophobic treatment, the subsequent step (c) performed as necessary can be further treated to improve the hydrophobicity by replacement with an organic solvent. In the comparative examples described below, it was confirmed that: if the forsterite fine particles subjected to the hydrophobic treatment, such as the fine particles according to the present embodiment, are not used, the fine particles settle with the lapse of a predetermined time when the organic solvent is replaced, and the dispersed state cannot be maintained.

In order to produce the silyl group represented by the formula (1) from the compound represented by the formula (2), water is required in an amount of preferably 1 to 4 moles per 1 mole of the organosilicon compound and/or the hydrolysate thereof. Such water may be contained in the organic solvent dispersion in advance, or may be added after the addition of the organosilicon compound.

Adding an organosilicon compound and/or a hydrolysate thereof and then curing. The curing temperature may be in the range of from room temperature to the boiling point of the hydrophilic organic solvent used, and if it is in the vicinity of the boiling point of the organic solvent, the silyl group reaction efficiency is high, which is preferable. The above-mentioned aging may be carried out under atmospheric pressure, preferably under reflux. Furthermore, the organosilicon compound of the formula (2) may be added with a hydrolysate which has been hydrolyzed in advance.

By performing the step (b), the particles having a particle size of 1nm can be obtained²An organic solvent dispersion of silane-treated forsterite in which 1 to 5 silyl groups are bonded to the surface area of forsterite fine particles. The solid content concentration of the hydrophilic organic solvent dispersion is preferably 10 to 70% by mass based on the total metal oxide concentration of the silane-treated forsterite fine particles.

Here, the method for producing an organic solvent dispersion according to the present embodiment preferably further includes the following step (c).

(c) The process comprises the following steps: replacing at least a part of the dispersion medium in the organic solvent dispersion obtained in the step (b) with another organic solvent.

When the dispersion medium is replaced with another organic solvent, the temperature of the dispersion medium may be in the range of room temperature to the boiling point of the other organic solvent. The dispersion medium obtained in the step (c) has a total metal oxide concentration of 10 to 70 mass% based on the total metal oxide concentration of the silane-treated forsterite fine particles.

Examples of the other organic solvent include dimethylformamide (SP value: 12.0), methyl cellosolve (SP value: 11.4), ethyl cellosolve (SP value: 9.9), butyl cellosolve (SP value: 8.9), propylene glycol monomethyl ether (SP value: 10.5), propylene glycol monomethyl ether acetate (SP value: 8.7), methyl ethyl ketone (SP value: 9.3), methyl isobutyl ketone (SP value: 8.3), cyclohexanone (SP value: 9.8), ethyl acetate (SP value: 9.1), butyl acetate (SP value: 8.5), toluene (SP value: 8.9), methyl methacrylate (SP value: 9.9), pentaerythritol triacrylate (SP value: 10.0), dipentaerythritol hexaacrylate (SP value: 9.1), bisphenol a epoxy resin (SP value: 4.4), bisphenol F (SP value: 10.8), and the like, but the resin is not limited thereto. The other organic solvents for replacing the dispersion medium may be used alone in 1 kind, or 2 or more kinds may be used in combination.

When the organic solvent dispersion liquid according to the present embodiment has a large water content, the solubility of a heat-resistant resin such as an epoxy resin may be impaired when the organic solvent dispersion liquid is mixed with the heat-resistant resin. Therefore, the water content of the organic solvent dispersion liquid according to the present embodiment is preferably 5% by mass or less.

The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples.

Examples

[ measuring method of physical Properties ]

The physical properties were measured as follows.

Moisture content: determined by Karl Fischer titration (Karl Fischer titration).

Particle size by dynamic light scattering method: the dispersion was diluted with a dispersion solvent, and measured by a dynamic light scattering measuring apparatus (セ゛ータサイザーナノ S (trade name): マルバーン K) using the parameters of the solvent.

Specific gravity: the temperature was determined by hydrometer method (20 ℃).

Viscosity: the measurement was carried out with a BL type viscometer (25 ℃).

Specific surface area: determined by nitrogen adsorption method.

In addition, each 1nm²The number of bound silyl groups on the surface area of the silane-treated forsterite fine particles of (2) was calculated by CHN elemental analysis.

Production example 1 (production of forsterite Fine particles)

252.2g of citric acid monohydrate (16M, 100 mass% manufactured by Showa Denko K.K.) was dissolved in 2058.2g of pure water to obtain a 10.0 mass% citric acid aqueous solution. While stirring the obtained citric acid aqueous solution, 108.3g of magnesium hydroxide (UD-653, manufactured by UK マテリアルズ, having an MgO content of 65.7% by mass) was added thereto, and the mixture was stirred at room temperature for 1 hour to obtain a magnesium citrate aqueous solution. The solid content concentration (in terms of MgO) of the obtained magnesium citrate aqueous solution was 3.0 mass%.

190.9g of pure water was mixed with 425.2g of colloidal silica (スノーテックス (registered trademark) OXS, manufactured by nippon chemical industry, having a silica concentration of 10.6 mass% and a primary particle diameter of 5nm as observed by an electron microscope), and then 2022.4g of the above magnesium citrate aqueous solution was added thereto and stirred at room temperature for 30 minutes. Spray-drying with spray-dryer (パルビスミニスフ - レー GA-22, ヤマト science, Inc.) at inlet temperature of 180 deg.C and atomizing air pressure of 1.35kgf/cm²Absorber flow 0.30m³2639g of the obtained mixed solution was dried under the conditions of a liquid feeding rate of 5 g/min. The outlet temperature of the spray dryer at this time was 80. + -. 2 ℃. By repeating the above operation 2 times, 407.5g of a white dry powder was obtained in terms of a weight.

185g of the obtained dry powder was put in a crucible, and fired at 500 ℃ for 2 hours in the air using an electric furnace, and then fired at 800 ℃ for 2 hours in the air. The above firing operation was repeated 2 times to obtain 108.9g of white powder. The resulting white powder was identified by X-ray diffraction analysis, resulting in a phase which was substantially a single phase of forsterite and had a specific surface area of 15.5m as measured by nitrogen adsorption²/g。

[ example 1]

To 99g of the forsterite fine particles obtained in production example 1, 1240g of zirconia beads (bead diameter 1mm) and 231g of isopropyl alcohol were added, ball mill treatment was performed for 45 hours, and then the beads were removed, thereby obtaining 337g of forsterite fine particle slurry. The resulting forsterite fine particle slurry was fired at 300 ℃ to obtain a solid content concentration of 28.4 mass%. Then, 139g of isopropyl alcohol was added to 332g of the forsterite fine particle slurry, and wet grinding was performed by a bead mill using a continuous wet grinder (trade name: ウルトラアペックスミル UAM015, manufactured by shou industries, Ltd.). Zirconia beads (bead diameter: 0.05mm) were used as the beads, peripheral speed was 10m/s, and circulation flow rate was setThe treatment time was set to 1 hour at 100 mL/min. After wet grinding, the mixture was left to stand for 30 hours to remove the non-ground matter, thereby obtaining 367g of an isopropyl alcohol dispersion of forsterite fine particles. The obtained isopropyl alcohol-dispersed solution of forsterite fine particles had a solid content of 12.2 mass% and a water content of 0.7 mass%, and the specific surface area of the dried powder dried at 300 ℃ for 1 hour was 21.0m²/g。

246.3g of the obtained isopropyl alcohol dispersion of forsterite fine particles was placed in a 500mL egg-plant-shaped flask, and 0.85g of 3-methacryloxypropyltrimethoxysilane (trade name: KBM-503, manufactured by shin-Etsu chemical Co., Ltd.) as a silane coupling agent and 0.78g (equivalent to 1 nm) of 3-methacryloxypropyltrimethoxysilane were added thereto²3 pieces of 3-methacryloxypropyltrimethoxysilane) on the surface area of the forsterite fine particles in the oil bath, and reflux heating was performed for 5 hours to obtain 143g of an isopropyl alcohol dispersion of silane-treated forsterite fine particles. The obtained isopropyl alcohol dispersion had a water content of 0.5% by mass, a particle diameter by dynamic light scattering method of 313nm, a specific gravity of 0.938, and a viscosity of 4.6 mPas. The solid content concentration obtained by firing at 800 ℃ was 21.3% by mass.

[ example 2]

Regarding 118g of the isopropyl alcohol dispersion liquid of the silane-treated forsterite fine particles obtained in example 1, isopropyl alcohol was distilled off while adding 3.3L of methyl ethyl ketone at 150Torr using an evaporator, thereby replacing isopropyl alcohol with methyl ethyl ketone, and 131g of a methyl ethyl ketone dispersion liquid of the silane-treated forsterite fine particles was obtained. The obtained methyl ethyl ketone dispersion had a water content of 0.1% by mass, a particle diameter of 180nm by dynamic light scattering, a specific gravity of 0.912, and a viscosity of 0.8 mPas. The solid content concentration obtained by firing at 800 ℃ was 15.4% by mass.

The silane-treated forsterite methyl ethyl ketone dispersion obtained above was dried on a hot plate set at 130 ℃, and further vacuum-dried at 100 ℃. The resultant dried powder was pulverized by using an alumina mortar to make the particle size fine, and then dried at 150 ℃ for about 10 hours. The dielectric constant (dielectric constant) and dielectric loss tangent of the obtained silane-treated forsterite fine particles dried powder were measured by a perturbation mode oscillation method (perturbation mode ionization) using a special apparatus (Vector network analyzer, product of キーコム) under the conditions of a test frequency of 1GHz or 10GHz, a test temperature of about 24 ℃, a humidity of about 45%, and a number of measurements of 3 times. The silane-treated forsterite had a dielectric constant of 10.3(@1GHz) or 7.7(@10GHz), and a dielectric loss tangent (tan. delta.) of 0.005(@1GHz) or 0.007(@10 GHz). Generally, it is known that the dielectric loss tangent deteriorates with the fine particles, but in the present invention, the dielectric loss is small even in the high frequency ranges of 1GHz and 10GHz while maintaining a low value of less than 0.01, and the application to an insulating material or an insulating filler is expected.

Comparative example 1

100g of the isopropanol dispersion of the forsterite fine particles before silane treatment obtained in example 1 was replaced with methyl ethyl ketone by distilling off isopropanol with the addition of 1.0L of methyl ethyl ketone at 150Torr by using an evaporator, but the forsterite fine particles were precipitated by standing for 1 hour, and a methyl ethyl ketone dispersion of the forsterite fine particles could not be obtained.

[ example 3]

The production of various products containing the silane-treated forsterite fine particles was attempted using the organic solvent dispersion of silane-treated forsterite fine particles obtained in example 1. Here, attempts have been made to produce an electric wire coating agent, an insulating coating material, an insulator, an electronic pipe member, a circuit member substrate, and a semiconductor package. As a result, any of the above can be suitably produced. As described above, when the silane-treated forsterite fine particles, the organic solvent dispersion thereof, and the like of the present embodiment exemplified in example 1 are used for electronic components as an example, they can be used as an insulating material having low dielectric loss in a high frequency region, and can be improved in compatibility with a heat-resistant resin such as an epoxy resin and in packing density, and therefore it is expected that these various products are also excellent in various properties in the same manner.

Specific steps in the case of using the epoxy resin composite for electronic components as an example are as follows.

To 114.9g of the methyl ethyl ketone dispersion of silane-treated forsterite fine particles obtained in example 2, 41.3g of bisphenol F epoxy resin (YDF-8170C, manufactured by Nissan iron-based gold chemical Co., Ltd.) was added, and the mixture was stirred with a stirrer for 1 hour. Then, the solvent was removed by an evaporator at 60 ℃ and 80Torr for 1 hour, and at 60 ℃ and 30Torr for 1 hour. Further, the solvent was removed under a nitrogen flow at 60 ℃ and 30Torr for 30 minutes to completely remove the methyl ethyl ketone, thereby obtaining 59.0g of a bisphenol F type resin dispersion of silane-treated forsterite fine particles. The concentration of the silane-treated forsterite fine particles contained in the obtained bisphenol F-type epoxy resin dispersion was 30.0 mass%, and no aggregation, thickening, or the like was observed, and the dispersion was high in dispersibility and fluidity.

[ example 4]

26.5g of bisphenol F-type epoxy resin (YDF-8170C, manufactured by Nissian iron-based chemical Co., Ltd.) was added to 113.5g of the methyl ethyl ketone dispersion of silane-treated forsterite fine particles (solid content concentration of 15.6 mass% obtained by firing at 800 ℃) obtained by the method described in example 2, and 44.3g of the bisphenol F-type resin dispersion of silane-treated forsterite fine particles was obtained by the same method as described in example 3. The concentration of the silane-treated forsterite fine particles contained in the obtained bisphenol F-type epoxy resin dispersion was 40.0 mass%, and no aggregation, thickening, or the like was observed, and the dispersion had high dispersibility and fluidity.

[ example 5]

To 114.2g of the methyl ethyl ketone dispersion of silane-treated forsterite fine particles (solid content concentration 15.5 mass% obtained by firing at 800 ℃) obtained by the method described in example 2, 26.5g of hexahydrophthalic anhydride (リカシッド MH-700, new japanese national chemical & chemical company, inc.) was added, and by the same method as described in example 3, 44.3g of the hexahydrophthalic anhydride dispersion of silane-treated forsterite fine particles was obtained. The concentration of the silane-treated forsterite fine particles contained in the obtained hexahydrophthalic acid anhydride dispersion was 40.0 mass%, and a dispersion having high dispersibility was observed with a certain increase in viscosity, but no aggregation or the like was observed.

[ example 6]

To 59.0g of the bisphenol F epoxy resin dispersion obtained in example 3, 39.2g of hexahydrophthalic acid anhydride (リカシッド MH-700, manufactured by shinshi corporation) as a curing agent was added, and the mixture was stirred with a stirrer, and then 0.4g of dimethylbenzylamine (1 mass% based on the bisphenol F epoxy resin) as a curing accelerator was further added and stirred to obtain a varnish (varnish). The varnish thus obtained was degassed in vacuum, and then poured into a mold having a length of about 180mm, a width of about 145mm and a thickness of about 1mm, followed by heat treatment at 90 ℃ for 2 hours and heat treatment at 150 ℃ for 10 hours in an oven to carry out curing treatment. After gradually cooling, the mixture was taken out of the mold to obtain a silane-treated forsterite fine particle/epoxy resin composite. The concentration of the silane-treated forsterite fine particles contained in the obtained epoxy resin composite was 19.0 mass%, and the silane-treated forsterite fine particles were not aggregated as in the bisphenol F type epoxy resin dispersion liquid, and uniform dispersibility was maintained.

The withstand voltage test of the obtained silane-treated forsterite fine particle/epoxy resin composite was carried out using a dielectric breakdown tester (YST-243WS model, ヤマヨ tester) under the conditions of a test voltage of 20kV, a test frequency of 200Hz, a test temperature of about 20 ℃, a breakdown detection current value of 10mA, and a test number of 2 in accordance with JIS-C2110-1 or the like. The silane-treated forsterite fine particles/epoxy resin composite exhibited an average dielectric breakdown time of 43.5 hours, exhibited a dielectric breakdown time equal to or longer than that of an epoxy resin cured product containing no filler, and was applicable as an epoxy resin composite for electronic components having excellent insulation properties.

Comparative example 2

To 102.0g of methyl ethyl ketone was added commercially available high purity synthetic forsterite powder (HFF-SO, specific surface area 8.7 m)²ス pills made of enamelware) 18.0g, bisphenol F type epoxy resin (YDF-8170C, made by Nissian iron and Steel chemical Co., Ltd.) 42.0g, and60.0g of a bisphenol F type resin dispersion slurry of forsterite powder was obtained in the same manner as in example 3. To this mixture, 39.9g of hexahydrophthalic anhydride (リカシッド MH-700, manufactured by Nissian chemical Co., Ltd.) as a curing agent was added, and preparation of a forsterite powder/epoxy resin composite was attempted in the same manner as in example 6, but when the mixture was heated in an oven, the forsterite powder was precipitated in the mold, and an epoxy resin composite with uniform dispersibility could not be obtained.

Comparative example 3

To 102.0g of methyl ethyl ketone was added commercially available fused silica powder (SFP-20M, specific surface area 11.3M)²18.0 g/g (manufactured by electro chemical industry Co., Ltd.) and 42.0g of bisphenol F type epoxy resin (YDF-8170C, manufactured by Nissian iron Japan chemical Co., Ltd.) were prepared in the same manner as in example 3 to obtain 60.0g of bisphenol F type resin dispersion slurry of fused silica powder. To this mixture, 39.9g of hexahydrophthalic anhydride (リカシッド MH-700, manufactured by Nissi Kogyo Co., Ltd.) was added as a curing agent, and a fused silica powder/epoxy resin composite was obtained in the same manner as in example 6. The concentration of the fused silica powder contained in the obtained epoxy resin composite was 19.0 mass%, and no aggregation of the fused silica powder was observed, and uniform dispersibility was maintained. However, the dielectric breakdown time of the fused silica powder/epoxy resin composite measured by the same method as described in example 6 was 34.9 hours on average, and the epoxy resin composite was shorter than the epoxy resin cured product containing no filler, and the unevenness of the measurement was large, and it was not possible to obtain an epoxy resin composite having excellent insulation properties.