Classifications

• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
  • C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
  • C04B35/581—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on aluminium nitride
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/64—Burning or sintering processes
  • C04B35/645—Pressure sintering
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
  • C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
  • C04B41/81—Coating or impregnation
  • C04B41/82—Coating or impregnation with organic materials
  • C04B41/83—Macromolecular compounds
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
  • C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
  • C04B41/81—Coating or impregnation
  • C04B41/85—Coating or impregnation with inorganic materials
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/28—Nitrogen-containing compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L101/00—Compositions of unspecified macromolecular compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
  • C08L83/04—Polysiloxanes

Definitions

• An insulating substrate is provided at the bottom of a semiconductor device such as a power module represented by an inverter or the like.
• a semiconductor device such as a power module represented by an inverter or the like.
• heat resistance and thermal conductivity are required for such substrates.
• a ceramic material that meets these requirements at a high level is used for such a substrate.
• nitride ceramics that satisfy these required characteristics and have a relatively low specific density are often used.
• Patent Document 1 discloses an insulating material prepared by warm-pressing a mixture of boron nitride, a silsesquioxane derivative and a curing catalyst at 180 ° C. under a load of 120 MPa for 1 hour.
• Patent Document 2 discloses a nitride ceramic-resin composite material. That is, a mixed powder of amorphous boron nitride and any of hexagonal boron nitride, silicon nitride, and aluminum nitride is mixed in the presence of a sintering aid at 1850 to 2000 ° C., under pressure of 20 to 120 MPa, and in a nitrogen atmosphere. It is disclosed that a sintered body is obtained by sintering for 6 to 20 hours, and that the sintered body is impregnated with a heat-curable resin such as an epoxy resin and cured to prepare a ceramic resin composite. ..
• the composite material of boron nitride and the silsesquioxane derivative disclosed in Patent Document 1 did not have sufficient thermal conductivity. Further, in the composite material of the nitride ceramic sintered body containing boron nitride and the epoxy resin disclosed in Patent Document 2, a continuous body of the nitride ceramics containing boron nitride is formed in the composite material to improve the thermal conductivity. Since a long-time high-temperature pressurization process is required in a nitrogen atmosphere to secure the substrate, the merit in the manufacturing process is small as compared with the case where the substrate is composed of nitride ceramics such as silicon nitride alone. Moreover, the obtained composite material did not sufficiently satisfy the required characteristics.
• the epoxy resin has insufficient heat resistance and requires an aspect ratio of particles such as silicon nitride and boron nitride in the sintered body to be 5 or more. Therefore, due to its shape anisotropy, it has thermal conductivity. It was not possible to avoid the anisotropy of strength.
• the present specification provides ceramics / resin composite materials suitable for exhibiting properties such as thermal conductivity, heat resistance and insulation.
• the present inventors have studied various phase configurations and composite processes of composite materials suitable for exhibiting thermal conductivity, heat resistance and insulating properties in composite materials of ceramics and resins.
• a porous ceramic sintered body was obtained using ceramic powder of primary particles having an aspect ratio of less than 5, and then a resin was introduced into the pores of the porous sintered body to form a composite.
• the present specification provides the following means based on such findings.
• a porous ceramic sintered body phase in which ceramic particles having an aspect ratio of less than 5 are three-dimensionally bonded, and a resin phase composed of a resin in the pores of the porous ceramic sintered body are provided.
• Ceramics / resin composite material are provided.
• the porous ceramic sintered body phase is a metal element other than the metal element constituting the ceramic particles, and is Ca, Ba, Sr, Y, La, Ce, Pr, Nd, Sm, Gd, Dy.
• thermosetting resin contains a silsesquioxane derivative represented by the following formula (1).
• R 1 is an organic group having a carbon-carbon unsaturated bond and having 2 to 30 carbon atoms capable of hydrosilylation reaction, and R 2 , R 3 , R 4 and R 5 are independent of each other.
• a thermally conductive insulating element comprising the composite material according to any one of [1] to [6], wherein the resin is cured.
• a method for manufacturing a ceramic / resin composite material A step of firing a ceramic raw material composition containing ceramic particles having an aspect ratio of less than 5 to obtain a porous ceramic sintered body in which the ceramic particles are three-dimensionally bonded.
• the resin is a thermosetting resin and comprises a step of curing the thermosetting resin in the composite material.
• the ceramic raw material composition contains aluminum nitride.
• the porous ceramic sintered body is a metal element other than the metal element constituting the ceramic particles, and is Ca, Ba, Sr, Y, La, Ce, Pr, Nd, Sm, Gd, Dy, and so on.
• This specification relates to a ceramic / resin composite material having excellent thermal conductivity, heat resistance and insulating properties, a method for producing the same, and its use.
• the ceramic / resin composite material disclosed in the present specification (hereinafter, also simply referred to as the present composite material) can be obtained as follows. First, continuous fine particles formed by connecting ceramic particles that are superior in thermal conductivity and heat resistance to the resin in this composite material, and mainly contribute to thermal conductivity and heat resistance, and also contribute to insulation. A porous body having a pore structure is obtained in advance as a sintered body. Then, the composite material can be obtained by filling the pores of the porous sintered body with a resin that mainly contributes to insulating properties.
• the ceramic phase has a uniform pore structure (in other words, a continuous structure), isotropic thermal conductivity and excellent heat resistance can be ensured, and the pores can be secured.
• the insulating property which is presumed to be deteriorated due to the presence of, can be supplemented with the resin that fills the pores.
• the porous sintered body having a uniform pore structure has excellent resin permeability when the resin is introduced, and bubbles are easily removed, so that the pores are surely filled with the resin. Therefore, the present composite material can have good insulating properties.
• the conventional ceramics / resin composite material is composed of primary particles of nitrided ceramics having an aspect ratio of 5 or more by CIP forming the raw material powder under nitrogen pressurization at a high temperature for a long time in order to obtain a nitride ceramics continuum. It was something that required.
• a porous sintered body having a uniform pore structure can be used as a raw material, for example, a nitride ceramic powder, which is inexpensive and has good sinterability with an aspect ratio of less than 5. It can be easily obtained by firing in a short time.
• This composite material is useful for thermally conductive insulating elements and structures that require thermal conductivity (heat dissipation effect), heat resistance, and insulating properties.
• Examples of the structure to which the composite material is applied include semiconductor devices; various inverters; computer CPUs; LEDs and the like.
• the semiconductor device is not particularly limited, and examples thereof include a power semiconductor device constituting a so-called power module used for power conversion and power control.
• the elements and control circuits used in power semiconductor devices and the like are not particularly limited, and include various known elements and control circuits. Further, the semiconductor device in the present specification includes not only elements and control circuits but also semiconductor modules including units for heat dissipation and cooling.
• the heat conductive insulating element is a component that is supplied to a place where heat is to be dissipated and should be insulated and exhibits a heat dissipation function and an insulating function (current cutoff function).
• the heat conductive insulating element is not particularly limited, and examples thereof include an insulating layer and an insulating film in various electronic components and semiconductor devices, as well as an insulating film, an insulating sheet, and an insulating substrate.
• This composite material is a resin phase composed of a porous ceramic sintered phase in which ceramic particles having an aspect ratio of less than 5 are three-dimensionally bonded and a resin in the pores of the porous ceramic sintered phase. And can be provided.
• the porous ceramic sintered body phase (hereinafter, also simply referred to as a ceramic phase) in this composite material has a porous structure in which ceramic particles are three-dimensionally bonded.
• a porous structure is generally called an aggregate type, which is a structure in which ceramic particles as a raw material are sintered and solidified at mutual contacts.
• the pores in such a porous structure are composed of gaps between particles.
• the pores exist mainly as gaps between the primary particles, and when such a porous structure is mainly composed of secondary particles, the pores are present. There may be predominantly mutual gaps between secondary particles.
• the porous structure is composed of primary particles and secondary particles, the gaps between the particles are pores.
• the secondary particles are generally obtained, for example, by aggregating or granulating the primary particles.
• Such a porous structure is a sintered phase that is not completely densified. For this reason, the particle size and aspect ratio of the ceramic particles used as raw materials tend to be maintained even in the ceramic phase, and the ceramic particle morphology (average particle size, aspect ratio, etc.) is also evaluated in the ceramic phase and composite materials. can do.
• the ceramics are not particularly limited, and examples thereof include aluminum nitride, alumina, boron nitride, silicon carbide, silicon nitride, silica, aluminum hydroxide, barium sulfate, magnesium oxide, and zinc oxide.
• the ceramics one kind or two or more kinds can be used depending on the use of this composite material and the like.
• nitride ceramics such as aluminum nitride, boron nitride and silicon nitride can be preferably used. These have a thermal conductivity of 20 W / (m ⁇ k) or more even if the porous body has pores remaining. In addition, it is excellent in adhesion to a silsesquioxane derivative as a thermosetting resin described later.
• Aluminum nitride and boron nitride can be preferably used from the viewpoints of wettability with a resin and ease of manufacture, in addition to thermal conductivity. More preferably, aluminum nitride can be used in consideration of the low aspect ratio and the low-temperature sinterability. Due to the low temperature sinterability of aluminum nitride, the porosity can be easily adjusted by discharge plasma sintering.
• the average particle size of the ceramics primary particles is, for example, 0.2 ⁇ m or more and 100 ⁇ m or less. Further, for example, it is 0.5 ⁇ m or more and 50 ⁇ m or less, and for example, 0.5 ⁇ m or more and 40 ⁇ m or less, and for example, 0.5 ⁇ m or more and 30 ⁇ m or less, and for example, 0.5 ⁇ m or more and 20 ⁇ m or less, and for example. , 0.5 ⁇ m or more and 10 ⁇ m or less, and for example, 0.5 ⁇ m or more and 5 ⁇ m or less.
• the upper limit is 50 ⁇ m, more preferably 40 ⁇ m or less, still more preferably 30 ⁇ m or less.
• the ceramics phase is mainly composed of secondary particles in which primary particles are aggregated or aggregated, and these secondary particles are interconnected to form a porous structure, the ceramics secondary is formed.
• the average particle size of the particles the aspect of the average particle size of the primary particles can be applied as it is.
• the average particle size of the ceramic primary particles in this case is not particularly limited, but is, for example, 50 nm or more and 300 nm or less, and for example, 100 nm or more and 200 nm or less.
• the method for measuring the average particle size of the ceramic primary particles and secondary particles in the ceramic phase can be measured by the following method. After embedding the ceramic phase with resin, it is processed by the CP (cross section polisher) method, fixed to the sample table, and then platinum coated. After that, an SEM image is taken with a scanning electron microscope, for example, "S-4800" (manufactured by Hitachi High-Technology Co., Ltd.), and the obtained particle image of the cross section is image analysis software, for example, "ImageJ” (https: //). It can be imported into imagej.nih.gov/ij/) and measured. In the example, the number of pixels for image analysis was 1.23 million pixels.
• the "diameter" of the ceramic particles means the diameter of the smallest circle that can surround the particles to be observed.
• the aspect ratio of the ceramic primary particles is, for example, less than 5. This is because when the aspect ratio of the ceramic primary particles in the ceramic phase is 5 or more, a non-uniform pore structure is formed and anisotropy is likely to occur in the ceramic phase. This is because, in general, a uniform pore structure can be easily obtained, and the anisotropy of the obtained ceramic phase is suppressed. Further, according to the uniform pore structure, when the resin is introduced into the pores, air bubbles are easily released, the resin is introduced uniformly, and the insulating property can be easily maintained.
• the aspect ratio is also, for example, 4 or less, and is, for example, 3 or less, and is, for example, 2 or less, and is, for example, 1.5 or less, and is, for example, 1.3 or less, and is, for example. , 1.2 or less, and for example, 1.1 or less.
• the aspect ratio of the ceramic secondary particles can be applied as it is to the above-mentioned aspect ratio of the primary particles. Further, the aspect ratio of the ceramic primary particles in this case is not particularly limited.
• the aspect ratio of ceramic primary particles and secondary particles can be measured by the following method. After embedding the ceramic phase with resin, it is processed by the CP (cross section polisher) method, fixed to the sample table, and then platinum coated. After that, an SEM image is taken with a scanning electron microscope, for example, "S-4800" (manufactured by Hitachi High-Technology Co., Ltd.), and the obtained particle image of the cross section is analyzed by image analysis software, for example, "ImageJ” (https: // imagej). It can be imported into .nih.gov/ij/) and measured. In the example, the number of pixels for image analysis was 1.23 million pixels.
• the "major diameter” of the ceramic particles is the diameter of the smallest circle that can surround the particles to be observed, and the “minor diameter” of the ceramic particles is surrounded by the particles to be observed. It means the diameter of the maximum circle that can be made.
• the morphology of the ceramic primary particles and the secondary particles in the ceramic phase is not particularly limited as long as the aspect ratio is less than 5, but for example, spherical, rod-shaped, needle-shaped, columnar, fibrous, plate-shaped, scaly, etc. Examples thereof include nanosheets and nanofibers, which may be crystalline or amorphous. It is preferably spherical.
• the porosity of the ceramic phase is not particularly limited, but is, for example, 5% or more, for example, 10% or more, and for example, 15% or more. Further, for example, the porosity is 40% or less, for example, 35% or less, and for example, 30% or less.
• the closed porosity of the ceramic phase is, for example, 5% or less, for example, 3% or less, and for example, 1% or less. This is because the smaller the closed porosity, the better the insulating property.
• the closed porosity can be measured by the difference between the measured density by the Archimedes method and the theoretical density. The method for measuring the porosity of the ceramic phase will be described later.
• the average pore diameter of the ceramic phase is, for example, 0.1 to 30.0 ⁇ m from the viewpoint of resin introduction.
• the average pore diameter is based on JIS R 1655: 2003, and the integrated value of the pore diameter volume when a cumulative pore diameter distribution curve (see Figure 6 of JIS R 1655: 2003) is created using a mercury porosimeter is the entire value (see Figure 6).
• the pore diameter is 50% of the cumulative pore volume value).
• the ceramic phase can be, for example, 25% by volume or more and 95% by volume or less of the present composite material. If it is smaller than 25% by volume, the thermal conductivity becomes too low, and if it exceeds 95% by volume, the adhesiveness due to the resin becomes too low and the probability of occurrence of closed pores increases. be.
• the ratio is also, for example, 30% by volume or more and 90% by volume or less, for example, 35% by volume or more and 85% by volume or less, and for example, 35% by volume or more and 80% by volume, and for example, 40% by volume. It is 75% by volume or less.
• the lower limit value and the upper limit value in these ranges can be combined with other upper limit values and lower limit values, respectively.
• the ratio of the ceramic phase in the composite material can be determined by measuring the bulk density and the true density of the sintered ceramic porous body.
• Bulk density (D) of ceramic phase mass / volume ...
• Porosity of ceramic phase (%) (1- (D / true density of ceramic phase))
• x 100 ratio of resin phase (%) ...
• Ratio of ceramic phase (%) 100-Ratio of resin phase ...
• the bulk density of the ceramic phase is measured by the volume calculated from the diameter of the disk-shaped ceramic phase (measured by calipers) and the electronic balance in accordance with the measurement method of density and specific gravity by geometric measurement of JIS Z 8807: 2012. It is determined from the mass (see Section 9 of JIS Z 8807: 2012).
• the true density of the ceramic phase is determined from the volume and mass of the ceramic phase measured using a dry automatic densitometer in accordance with the method of measuring density and specific gravity by the gas substitution method of JIS Z 8807: 2012 (JIS Z). 8807: 2012, paragraph 11 equations (14) to (17)).
• the content of metal elements other than the constituent metal elements of the ceramic used is, for example, 1% by mass or less with respect to the total mass of the ceramic phase.
• Low melting point compounds and impurities constituting the sintering aid and the like are generally considered to reduce the thermal conductivity and / or the insulating property.
• the content (total amount) of such other metal elements can be reduced as described above by obtaining a porous body by utilizing plasma sintering as described later.
• the content of these other metal elements is, for example, 0.8% by mass or less, for example, 0.6% by mass or less, or, for example, the total mass of the ceramic phase. It can be 0.4% by mass or less, for example, 0.2% by mass or less, and for example, 0.1% by mass or less.
• the content of the metal element derived from the sintering aid is, for example, 3% by mass or less, for example, 2.5% by mass or less, or, for example, the mass of the ceramic phase. It can be 2% by mass or less, for example, 1.5% by mass or less, and for example, 1% by mass or less.
• metal elements are typically metal elements of compounds used as sintering aids.
• the compound used as a sintering aid varies depending on the type of ceramics, but is a metal element other than the constituent metal elements of ceramics, and is, for example, Ca, Ba, Sr, Y, La, Ce, Pr, Nd, Sm. , Gd, Dy, B, Si, Mn, Mg and Al, which may be one or more selected from the group.
• aluminum nitride includes calcium carbonate, barium carbonate, strontium carbonate, yttrium oxide, lanthanum oxide, cerium oxide, placeodium oxide, neodymium oxide, samarium oxide, gadolinium oxide, dysprosium oxide, and the like.
• Examples thereof include Ca, Ba, Sr, Y, La, Ce, Pr, Nd, Sm, Gd and Dy.
• the boron nitride includes calcium carbonate, boric acid, aluminum oxide, tricalcium phosphate, and yttrium oxide, and the target metal elements include Ca, Al, Y, and the like.
• the silicon nitride is a rare earth element oxide such as yttrium oxide, and examples of the target metal element include rare earth elements such as yttrium, aluminum, magnesium and the like.
• the elemental composition of the ceramic phase can be quantified by fluorescent X-ray analysis (XRF).
• XRF fluorescent X-ray analysis
• the resin phase is composed of the resin in the pores of the ceramic phase. Since the resin phase fills the pores of the continuous pore structure, the resin phase itself can form a continuous phase, which contributes to good insulating properties.
• the resin phase may be either a thermoplastic resin or a thermosetting resin.
• the thermoplastic resin and the thermosetting resin can be used alone or in combination of two or more, respectively, as required.
• thermoplastic resin is not particularly limited, and a known thermoplastic resin can be used.
• a known thermoplastic resin can be used.
• Modified polyphenylene ether polyester, polyester such as polyethylene terephthalate and the like.
• polyethylene, polyvinyl chloride, acrylic resin and the like can be mentioned.
• thermosetting resin is not particularly limited, and a known thermosetting resin can be used.
• phenol resin, epoxy resin, unsaturated polyester, urethane resin, melamine resin, silicon resin, diallyl phthalate resin, alkyd resin and the like can be mentioned.
• phenol resin, epoxy resin and silicon resin can be mentioned from the viewpoint of heat resistance and the like.
• the silicon resin is not particularly limited, but may include, for example, a reactive functional group such as an addition-reactive functional group, a condensation-reactive functional group and a polymerizable functional group, and a silsesquioxane derivative and a poly such as silicone.
• a siloxane resin can be used.
• the addition reaction include a hydrosilylation reaction and a thiol-ene reaction
• examples of the condensation reaction include a dehydration condensation reaction and a dealcohol condensation reaction.
• the polymerizable functional group include an epoxy group, an oxetanyl group and the like, an acryloyl group, a methacryloyl group, a vinyl group and the like.
• the hydrolysis / polycondensation of the alkoxysilyl group in the silsesquioxane derivative, the hydrosilyl group in the silsesquioxane derivative and the carbon-carbon unsaturated group capable of hydrosilylation reaction A cured product of a silsesquioxane derivative having a crosslinked structure can be obtained by a functional group such as a hydrosilylation reaction.
• the silsesquioxane derivative itself is polycondensed by heating to construct a three-dimensional crosslinked structure, and by having a polymerizable functional group, a three-dimensional crosslinked structure having a higher degree of freedom and / or a degree of crosslinking can be obtained. Obtainable.
• the silsesquioxane derivative has excellent heat resistance and insulating properties, and is itself a liquid at room temperature (5 ° C to 35 ° C), so that no special solvent or heating is required for introduction into the pore structure. Therefore, it is suitable.
• the silsesquioxane derivative is not particularly limited, and a known silsesquioxane derivative can be used.
• the silsesquioxane derivative represented by the following formula (hereinafter, also referred to as the present silsesquioxane derivative) is preferably used as the silsesquioxane derivative. be able to. This silsesquioxane derivative is also excellent in thermal conductivity.
• R 1 is an organic group having a carbon-carbon unsaturated bond and having 2 to 30 carbon atoms capable of hydrosilylation reaction
• R 2 , R 3 , R 4 and R 5 are independent of each other.
• t, u, w and x is a positive number and s
• v and y are 0 or a positive number.
• structural unit (a) to (g) Each structural unit from left to right in the above formula (1) that can be possessed by the present silsesquioxane derivative shall be referred to as structural unit (a) to (g), and will be described below.
• S, t, u, v, w, x and y in the formula (1) represent the molar ratio of each constituent unit.
• s, t, u, v, w, x and y are the relative molar ratios of the constituent units contained in the present silsesquioxane derivative represented by the formula (1). show. That is, the molar ratio is a relative ratio of the number of iterations of each structural unit represented by the equation (1). The molar ratio can be determined from the NMR analysis value of the present silsesquioxane derivative. Further, when the reaction rate of each raw material of the present silsesquioxane derivative is clear or the yield is 100%, it can be obtained from the charged amount of the raw material.
• the sequence order in the formula (1) indicates the composition of the structural unit, and does not mean the sequence order. Therefore, the condensed form of the structural unit in the present silsesquioxane derivative does not necessarily have to be in the sequence order of the formula (1).
• the structural unit (a) is a Q unit having four O 1/2 (two as oxygen atoms) for one silicon atom.
• the ratio of the constituent unit (a) in the present silsesquioxane derivative is not particularly limited, but considering the viscosity of the present silsesquioxane derivative, for example, the molar ratio in all the constituent units (s / (s + t + u + v + w + x + y)). ) Is 0.1 or less, and is, for example, 0.
• the structural unit (b) is a T unit having three O 1/2 (1.5 as oxygen atoms) for one silicon atom.
• R 1 can represent an organic group having a carbon-carbon unsaturated bond and having 2 to 30 carbon atoms capable of hydrosilylation reaction. That is, the organic group R 1 can be a functional group having a carbon-carbon double bond or a carbon-carbon triple bond capable of hydrosilylation reaction.
• organic group R 1 are not particularly limited, but for example, a vinyl group, an orthostyryl group, a metastyryl group, a parastyryl group, an acryloyloxymethyl group, a methacryloyloxymethyl group, and a 2-acryloyloxyethyl group.
• Silsesquioxane derivative represented by Formula (1) is an organic group R 1 as a whole may comprise two or more, in which case all of the organic radical R 1, may be identical to each other, It may be different.
• the organic group R 1 for example, a vinyl group having a small number of carbon atoms and a 2-propenyl group (allyl group) can be easily obtained as a raw material monomer forming a structural unit (1-2).
• the inorganic portion means a SiO portion.
• R 1 is an alkylene group (divalent aliphatic group) having 1 to 20 carbon atoms, a divalent aromatic group having 6 to 20 carbon atoms, or a divalent aromatic group having 6 to 20 carbon atoms, as exemplified above. It can contain at least one selected from divalent aliphatic ring groups having 3 to 20 carbon atoms.
• alkylene group having 1 to 20 carbon atoms include a methylene group, an ethylene group, an n-propylene group, an i-propylene group, an n-butylene group and an i-butylene group.
• Examples of the divalent aromatic group having 6 to 20 carbon atoms include a phenylene group and a naphthylene group.
• Examples of the divalent alicyclic group having 3 to 20 carbon atoms include a divalent hydrocarbon group having a norbornene skeleton, a tricyclodecane skeleton, or an adamantane skeleton.
• R 1 is an organic group having 2 to 30 carbon atoms, and the fact that the number of carbon atoms is small increases the proportion of the inorganic portion of the cured product of this silsesquioxane derivative and makes it excellent in heat resistance.
• the number of carbon atoms is preferably 2 to 20, more preferably 2 to 10, and even more preferably 2 to 5.
• a vinyl group and a 2-propenyl group (allyl group) having a small number of carbon atoms are particularly suitable.
• the structural unit (c) is a T unit having three O 1/2 for one silicon atom.
• R 2 can be at least one selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms and an aralkyl group having 7 to 10 carbon atoms.
• the structural unit (c) is different from the structural unit (d) described later in that it does not contain a hydrogen atom.
• the structural unit (c) contributes to the improvement of the thermal conductivity of the present silsesquioxane derivative.
• the amount of hydrogen atom remaining in the cured product of the present silsesquioxane derivative can be reduced. In addition, it can contribute to an increase in the molar ratio of C / Si of the present silsesquioxane derivative. Further, the hydrosilylation reaction in the present silsesquioxane derivative can be regulated between the structural unit (a) and the structural unit (f), and the structural regularity can be improved and the thermal conductivity can be improved. In some cases.
• the alkyl group having 1 to 10 carbon atoms may be either an aliphatic group or an alicyclic group, and may be linear or branched. Although not particularly limited, examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group and the like. From the viewpoint of thermal conductivity, for example, a methyl group, an ethyl group and the like can be mentioned. Also, for example, it is a methyl group.
• the aryl group having 6 to 10 carbon atoms is not particularly limited, and examples thereof include a phenyl group and a phenyl group substituted with an alkyl group having 1 to 4 carbon atoms. From the viewpoint of thermal conductivity, for example, a phenyl group can be mentioned.
• the aralkyl group having 7 to 10 carbon atoms is not limited to, and examples thereof include an alkyl group in which one of the hydrogen atoms of an alkyl group having 1 to 4 carbon atoms is substituted with an aryl group such as a phenyl group.
• an aryl group such as a phenyl group.
• a benzyl group and a phenethyl group can be mentioned.
• R 2 is included in the structural unit (c), such as a methyl group, when an alkyl group having 1 to 4 carbon atoms, can also more R 3 in the structural unit (e) to be described later is the same. By doing so, the thermal conductivity and the dispersibility of the filler can be improved. Further, when R 2 is an aryl group such as a phenyl group or an aralkyl group such as a phenyl group, a plurality of R 3 in the structural units (e) and (D units) described later can also be the same. By doing so, the thermal conductivity and the dispersibility of the filler can be improved.
• R 2 is an alkyl group having 1 to 4 carbon atoms such as a methyl group, it can be the same as R 4 in the structural unit (f). Similarly, it can be the same as R 5 in the constituent unit (g).
• R 2 is more preferably a methyl group or a phenyl group because it has a good balance between heat resistance, dispersibility and viscosity.
• the structural unit (d) is also a T unit having three O 1/2 for one silicon atom, but the structural unit (d) is a structural unit (c). Unlike, it has a hydrogen atom that binds to a silicon atom.
• the ratio of the constituent unit (d) in the present silsesquioxane derivative is not particularly limited, but considering the thermal conductivity and heat resistance of the present silsesquioxane derivative, for example, the molar ratio in all the constituent units is It is 0.1 or less, and is, for example, 0.
• the structural unit (e) is a D unit having two O 1/2 (one as an oxygen atom) for one silicon atom.
• R 3 can represent at least one selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms and an aralkyl group having 7 to 10 carbon atoms.
• the plurality of R 3 contained in the structural unit (e) may be homologous, or may be going.
• Each of these substituents includes various embodiments defined for R 3 of the structural unit (c).
• the structural unit (f) is a unit having one O 1/2 (0.5 oxygen atom) for one silicon atom.
• R 4 can represent at least one selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms and an aralkyl group having 7 to 10 carbon atoms.
• the plurality of R 4 contained in the structural unit (f) may be homologous, or may be going.
• Each of these substituents includes various embodiments defined for R 2 of the structural unit (c).
• the structural unit (g) is an M unit having one O 1/2 (0.5 oxygen atom) for one silicon atom.
• the structural unit (g) is different from the structural unit (f) in that it does not have a hydrogen atom bonded to a silicon atom and all of them are alkyl groups or the like. With this structural unit, the organicity of the present silsesquioxane derivative can be improved, and the viscosity can also be lowered.
• R 5 can represent at least one selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms and an aralkyl group having 7 to 10 carbon atoms.
• the plurality of R 5 contained in the structural unit (g) may be homologous, or may be going.
• Each of these substituents includes various embodiments defined for R 2 of the structural unit (c).
• the present silsesquioxane derivative can further include [R 6 O 1/2 ] as a constituent unit containing no Si.
• R 6 is a hydrogen atom and / or an alkyl group having 1 to 6 carbon atoms, which may be an aliphatic group or an alicyclic group, and may be linear or branched.
• Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group and the like.
• This structural unit is an alkoxy group which is a hydrolyzable group contained in a raw material monomer described later, or an alkoxy group generated by substituting an alcohol contained in a reaction solvent with a hydrolyzable group of the raw material monomer. , Those remaining in the molecule without hydrolysis / polycondensation, and / or hydroxyl groups remaining in the molecule without hydrolysis / polycondensation.
• each structural unit of the present silsesquioxane derivative can independently take various embodiments, and for example, R 1 is preferably a vinyl group, an allyl group or the like. Further, for example, R 2 , R 3 , R 4 and R 5 in the constituent units (c), the same (e), the same (f) and the same (g) are independently each of the number of carbon atoms such as a methyl group. It is preferable that it is an alkyl group of 1 to 10, more preferably R 2 and R 3 are the same alkyl group such as a methyl group, and more preferably R 2 , R 3 and R 4 are.
• the same alkyl group such as a methyl group, and even more preferably the same alkyl group such as R 2 , R 3 , R 4 and R 5 (where 0 ⁇ y), methyl group and the like.
• R 2 and R 3 in the structural units (c) and (e) are aryl groups such as phenyl groups, and the same (f) and (g) are alkyl groups such as methyl groups. Is.
• t, u, w and x are positive numbers, and s, v and y are 0 or positive numbers.
• the molar ratio of 0 means that the constituent unit is not included.
• the ratio of the constituent unit (a) in the present silsesquioxane derivative is not particularly limited, but considering the viscosity of the present silsesquioxane derivative, the molar ratio (s /) in all the constituent units of the formula (1). (S + t + u + v + w + x + y)), for example, 0.1 or less, and for example, 0.
• the ratio of the constituent unit (b) in the present silsesquioxane derivative is not particularly limited, but considering the curability of the present silsesquioxane derivative and the like, the molar ratio among all the constituent units of the formula (1) ( As t / (s + t + u + v + w + x + y)), for example, it is more than 0 and 0.3 or less.
• the structural unit (b) which is a T unit having crosslink reactivity, at such a molar ratio, a silsesquioxane derivative having a good crosslink structure can be obtained.
• the molar ratio is 0.1 or more, for example, 0.15 or more, and for example, 0.17 or more, and for example, 0.18 or more, and for example, 0. 20 or more, and for example, 0.25 or more. Further, for example, it is 0.28 or less, for example, 0.27 or less, and for example, 0.26 or less. These lower and upper limits can be combined, but are, for example, 0.1 or more and 0.27 or less, and for example, 0.15 or more and 0.26 or less.
• the ratio of the constituent unit (c) in the present silsesquioxane derivative is not particularly limited, but considering the thermal conductivity and the like of the present silsesquioxane derivative, the molar ratio in all the constituent units of the formula (1).
• (u / (s + t + u + v + w + x + y)) for example, it is more than 0 and 0.6 or less.
• 0.2 or more for example, 0.3 or more, and for example, 0.35 or more, and for example, 0.4 or more, and for example, 0.45 or more.
• it is 0.5 or more, and for example, 0.55 or more.
• it is 0.55 or less, for example, 0.5 or less, and for example, 0.4 or less.
• 0.55 or less for example, 0.5 or less, and for example, 0.4 or less.
• the ratio of the constituent unit (d) in the present silsesquioxane derivative is not particularly limited, but in consideration of the thermal conductivity and heat resistance of the present silsesquioxane derivative, it occupies all the constituent units of the formula (1).
• the molar ratio (v / (s + t + u + v + w + x + y)) is, for example, 0.1 or less, for example, 0.05 or less, and for example, 0.
• u> v it means that the number of the constituent units (c) is larger than that of the constituent units (d) with respect to the constituent units (c) and the same (d), which are both T units.
• u / (u + v) is, for example, 0.6 or more, for example 0.7 or more, and for example 0.8 or more, and for example 0.9 or more.
• the ratio of the constituent unit (e) in the present silsesquioxane derivative is not particularly limited, but considering the viscosity of the present silsesquioxane derivative and the like, the molar ratio (w) in all the constituent units of the formula (1). / (S + t + u + v + w + x + y)), for example, more than 0 and 0.2 or less. Further, for example, it is 0.05 or more, and for example, 0.07 or more, for example, 0.08 or more, and for example, 0.09 or more, and for example, 0.1 or more. Further, for example, it is 0.18 or less, for example, 0.16 or less, and for example, 0.15 or less. These lower and upper limits can be combined, but are, for example, 0.04 or more and 0.15 or less, and for example, 0.05 or more and 0.1 or less.
• the ratio of the constituent unit (f) in the present silsesquioxane derivative is not particularly limited, but considering the heat resistance, viscosity, curability and the like of the present silsesquioxane derivative, all the constituent units of the formula (1) are considered.
• the molar ratio (x / (s + t + u + v + w + x + y)) to the above 0 is, for example, more than 0 and 0.3 or less. Further, for example, the molar ratio is 0.1 or more, for example, 0.15 or more, and for example, 0.17 or more, and for example, 0.18 or more, and for example, 0. 20 or more, and for example, 0.25 or more.
• it is 0.28 or less, for example, 0.27 or less, and for example, 0.26 or less.
• 0.28 or less for example, 0.27 or less, and for example, 0.26 or less.
• the ratio of the constituent unit (g) in the present silsesquioxane derivative is not particularly limited, but the molar ratio to all the constituent units (y / (s + t + u + v + w + x + y)) in consideration of the viscosity of the present silsesquioxane derivative and the like.
• it is 0 or more and 0.1 or less, and for example, 0 or more and 0.08 or less, and for example, 0 or more and 0.05 or less, and for example, 0.
• x> y in consideration of curability and heat resistance.
• the constituent unit (f) which is an M unit it is possible to contribute to the decrease in the viscosity of this silsesquioxane, but when the constituent unit (g) which is another M unit is large, the curability and heat resistance are improved. This is because there is a risk of deterioration.
• x / (x + y) is, for example, 0.5 or more, for example, 0.7 or more, for example, 0.8 or more, and for example, 0.9 or more, and for example, 1. be.
• A is a vinyl group
• R 2 , R 3 and R 4 are methyl groups (however, when 0 ⁇ y, R 5 Is a methyl group.).
• the molar ratio of C / Si is, for example, more than 0.9. This is because the thermal conductivity is improved in this range. Further, for example, the molar ratio is 1 or more, and for example, 1.2 or more.
• the molar ratio of C / Si can be obtained, for example, by evaluating the present silsesquioxane derivative by 1 H-NMR measurement.
• Signals with a chemical shift ⁇ (ppm) of -0.2 to 0.6 are based on the structure of Si-CH 3
• signals with a ⁇ (ppm) of 0.8 to 1.5 are OCH (CH 3 ) CH 2 CH 3
• Signals with ⁇ (ppm) of 3.5 to 3.9 are based on the structure of OCH (CH 3 ) 2 and OCH 2 CH 3
• signals with ⁇ (ppm) of 3.9 to 4 are based on the structure of OCH 2 CH 3.
• the signal of .1 is based on the structure of OCH (CH 3 ) CH 2 CH 3
• the signal of ⁇ (ppm) 4.2 to 5.2 is based on the structure of Si—H
• ⁇ (ppm) is 5.7.
• the structural unit T since it is known that the charged monomers (triethoxysilane, trimethoxyvinylsilane, etc.) are directly incorporated into the silsesquioxane derivative, the charged values of all the monomers and the NMR measurement values are used. , The molar ratio of each constituent unit contained in the silsesquioxane derivative can be determined, and further, the C / Si molar ratio can be determined.
• the number average molecular weight of the present silsesquioxane derivative is preferably in the range of 300 to 30,000.
• Such silsesquioxane is itself a liquid, has a low viscosity suitable for handling, is easily dissolved in an organic solvent, is easy to handle the viscosity of the solution, and is excellent in storage stability.
• the number average molecular weight is more preferably 500 to 15,000, still more preferably 700 to 10,000, and particularly preferably 1,000 to 5,000.
• the number average molecular weight can be determined by GPC (gel permeation chromatograph), for example, using polystyrene as a standard substance under the measurement conditions in [Example] described later.
• the present silsesquioxane derivative is liquid and preferably has a viscosity at 25 ° C. of 100,000 mPa ⁇ s or less, more preferably 80,000 mPa ⁇ s or less, and 50,000 mPa ⁇ s or less. It is particularly preferable to have. However, the lower limit of the viscosity is usually 1 mPa ⁇ s.
• the viscosity can be measured at 25 ° C. using an E-type viscometer (TVE22H type viscometer manufactured by Toki Sangyo Co., Ltd.).
• the present silsesquioxane derivative can be produced by a known method.
• the method for producing the silsesquioxane derivative is described in International Publication No. 2005/01007, Pamphlet 2009/066608, Pamphlet 2013/099909, Japanese Patent Application Laid-Open No. 2011-052170, Japanese Patent Application Laid-Open No. 2013-147695. Etc. are disclosed in detail as a method for producing polysiloxane.
• the present silsesquioxane derivative can be produced, for example, by the following method. That is, the method for producing the present silsesquioxane derivative includes a condensation step of hydrolyzing and polycondensing the raw material monomer giving the structural unit in the above formula (1) by condensation in an appropriate reaction solvent. Can be done.
• a silicon compound having four siloxane bond-forming groups (hereinafter referred to as “Q monomer”) forming the structural unit (a) (Q unit) and the structural units (b) to ( d)
• a silicon compound having three siloxane bond-forming groups (hereinafter referred to as “T monomer”) that forms (T unit) and a siloxane bond-forming group that forms structural units (e) (D unit).
• T monomer A silicon compound (hereinafter referred to as “M monomer”) forming a structural unit (f) and (g) (M unit) having two silicon compounds (hereinafter referred to as "D monomer”) and one siloxane bond-forming group. ”) And can be used.
• a T monomer forming the structural unit (b), a T monomer forming the structural units (c) and (d), a D monomer forming the structural unit (e), and a structural unit ( At least one of each of the M monomers forming f) and (g) is used. It is preferable to include a distillation step in which the reaction solvent, by-products, residual monomers, water and the like in the reaction solution are distilled off after the raw material monomer is hydrolyzed and polycondensed in the presence of the reaction solvent.
• the siloxane bond-forming group contained in the Q monomer, T monomer, D monomer or M monomer which is the raw material monomer is a hydroxyl group or a hydrolyzable group.
• examples of the hydrolyzable group include a halogeno group and an alkoxy group.
• At least one of the Q monomer, T monomer, D monomer and M monomer preferably has a hydrolyzable group.
• the hydrolyzable group is preferably an alkoxy group, and more preferably an alkoxy group having 1 to 3 carbon atoms, because the hydrolyzable group is good and no acid is produced as a by-product.
• the siloxane bond-forming group of the Q monomer, T monomer or D monomer corresponding to each structural unit is preferably an alkoxy group
• the siloxane bond-forming group contained in the M monomer is preferably an alkoxy group or a syroxy group. ..
• the monomer corresponding to each structural unit may be used alone or in combination of two or more.
• Examples of the Q monomer giving the structural unit (a) include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane.
• Examples of the T monomer giving the structural unit (b) include trimethoxyvinylsilane, triethoxyvinylsilane, (p-styryl) trimethoxysilane, (p-styryl) triethoxysilane, (3-methacryloyloxypropyl) trimethoxysilane, and ( Examples thereof include 3-methacryloyloxypropyl) triethoxysilane, (3-acryloyloxypropyl) trimethoxysilane, and (3-acryloyloxypropyl) triethoxysilane.
• T monomer giving the structural unit (c) examples include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltriethoxysilane, and butyltri. Examples thereof include methoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane and the like.
• T monomer giving the structural unit (d) examples include trimethoxysilane, triethoxysilane, tripropoxysilane, and trichlorosilane.
• Examples of the D monomer giving the structural unit (e) include dimethoxydimethylsilane, dimethoxydiethylsilane, diethoxydimethylsilane, diethoxydiethylsilane, dipropoxydimethylsilane, dipropoxydiethylsilane, dimethoxybenzylmethylsilane, and diethoxybenzylmethylsilane. , Dichlorodimethylsilane, dimethoxymethylsilane, dimethoxymethylvinylsilane, diethoxymethylsilane, diethoxymethylvinylsilane and the like.
• Examples of the M monomer giving the structural units (f) and (g) include hexamethyldisiloxane, hexaethyldisiloxane, and hexapropyldisiloxane, 1,1,3,3, which give two structural units (f) by hydrolysis.
• 1,3-divinyl-1,1,3,3-tetramethyldisiloxane methoxydimethylsilane, ethoxydimethylsilane, methoxydimethylvinylsilane, ethoxydimethylvinylsilane, methoxytrimethylsilane, ethoxytrimethylsilane , Methoxydimethylphenylsilane, ethoxydimethylphenylsilane, chlorodimethylsilane, chlorodimethylvinylsilane, chlorotrimethylsilane, dimethylsilanol, dimethylvinylsilanol, trimethylsilanol, triethylsilanol, tripropylsilanol, tributylsilanol and the like.
• the organic compound giving the structural unit (h) include alcohols such as 2-propanol, 2-butanol
• Alcohol can be used as the reaction solvent in the condensation step.
• the alcohol is an alcohol in a narrow sense represented by the general formula R-OH, and is a compound having no functional group other than an alcoholic hydroxyl group. Specific examples thereof include, but are not limited to, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, 2-butanol, 2-pentanol, 3-pentanol, 2-methyl-2-butanol, 3-.
• Methyl-2-butanol, cyclopentanol, 2-hexanol, 3-hexanol, 2-methyl-2-pentanol, 3-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-3 -Pentanol, 2-ethyl-2-butanol, 2,3-dimethyl-2-butanol, cyclohexanol and the like can be exemplified.
• these alcohols can be used alone or in combination of two or more.
• a more preferred alcohol is a compound capable of dissolving water at the concentration required in the condensation step.
• An alcohol having such properties is a compound having a water solubility of 10 g or more per 100 g of alcohol at 20 ° C.
• the alcohol used in the condensation step is 0.5% by mass or more based on the total amount of all reaction solvents, including the additional charge during the hydrolysis / polycondensation reaction. It is possible to suppress the gelation of the derivative.
• the amount used is preferably 1% by mass or more and 60% by mass or less, and more preferably 3% by mass or more and 40% by mass or less.
• the reaction solvent used in the condensation step may be only alcohol, or may be a mixed solvent with at least one kind of auxiliary solvent.
• the auxiliary solvent may be either a polar solvent or a non-polar solvent, or a combination of both may be used.
• Preferred polar solvents are secondary or tertiary alcohols having 3 or 7 to 10 carbon atoms, diols having 2 to 20 carbon atoms, and the like.
• the non-polar solvent is not particularly limited, and examples thereof include aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, chlorinated hydrocarbons, ethers, amides, ketones, esters, and cellosolves. Among these, aliphatic hydrocarbons, alicyclic hydrocarbons and aromatic hydrocarbons are preferable.
• the non-polar solvent is not particularly limited, but for example, n-hexane, isohexane, cyclohexane, heptane, toluene, xylene, methylene chloride and the like are preferable because they azeotrope with water, and these compounds are used in combination.
• xylene which is an aromatic hydrocarbon, is particularly preferable because it has a relatively high boiling point.
• the hydrolysis / polycondensation reaction in the condensation step proceeds in the presence of water.
• the amount of water used to hydrolyze the hydrolyzable group contained in the raw material monomer is preferably 0.5 to 5 times mol, more preferably 1 to 2 times mol, with respect to the hydrolyzable group.
• the hydrolysis / polycondensation reaction of the raw material monomer may be carried out without a catalyst or may be carried out using a catalyst.
• an acid catalyst exemplified by an inorganic acid such as sulfuric acid, nitric acid, hydrochloric acid, or phosphoric acid; or an organic acid such as formic acid, acetic acid, oxalic acid, or paratoluenesulfonic acid is preferably used.
• the amount of the acid catalyst used is preferably 0.01 to 20 mol% with respect to the total amount of silicon atoms contained in the raw material monomer, and is preferably 0.1 to 10 mol%. It is more preferable to have.
• an auxiliary agent can be added to the reaction system.
• examples thereof include a defoaming agent that suppresses foaming of the reaction solution, a scale control agent that prevents scale from adhering to the reaction tank and the stirring shaft, a polymerization inhibitor, a hydrosilylation reaction inhibitor, and the like.
• the amount of these auxiliaries used is arbitrary, but is preferably about 1 to 100% by mass with respect to the concentration of the present silsesquioxane derivative in the reaction mixture.
• the book produced by providing a distillation step of distilling off the reaction solvent and by-products, residual monomers, water and the like contained in the reaction solution obtained by the condensation step.
• the stability of the silsesquioxane derivative can be improved.
• the resin phase includes a silane coupling agent for improving the adhesion with the porous sintered ceramic phase, depending on the type of resin, and if necessary, wettability and leveling.
• a defoaming agent, a surface conditioner, a wet dispersant, a curing accelerator, a catalyst, etc. can be added to promote improvement of properties and decrease in viscosity to reduce the occurrence of defects during impregnation / curing.
• a catalyst described later can be appropriately used, if necessary. Those skilled in the art can appropriately select and use these various additives from known materials.
• the resin phase can be, for example, 15% by volume or more and 75% by volume or less of the present composite material. This is because if it is smaller than 15% by volume, the adhesiveness and the followability to the surface to be applied become too low, and if it exceeds 75% by volume, the thermal conductivity becomes too low.
• the ratio is also, for example, 20% by volume or more and 70% by volume or less, for example, 25% by volume or more and 65% by volume or less, and for example, 30% by volume or more and 65% by volume, and for example, 35% by volume. It is 65% by volume or less.
• the lower limit value and the upper limit value in these ranges can be combined with other upper limit values and lower limit values, respectively.
• the ceramic phase of this composite material can be manufactured by the discharge plasma sintering method described later.
• the discharge plasma sintering method easily realizes sintering of aggregate type porous body by electromagnetic energy by pulse energization, self-heating of material and discharge plasma energy generated between particles by pressurization and pulse energization. It is something to do. In general, there are various merits such as rapid sintering, suppression of grain growth, and possible sintering without a sintering aid.
• the method for producing this composite material includes a step of firing a raw material composition containing ceramic particles having an aspect ratio of less than 5 to obtain a porous ceramic sintered body in which the particles are three-dimensionally bonded, and a step of firing the porous ceramics.
• a step of filling the pores of the body with a resin to obtain the composite material can be provided. According to this manufacturing method, a composite material having isotropic and excellent thermal conductivity and excellent heat resistance and insulation can be easily manufactured.
• the aspects of the ceramics and particles constituting the ceramic phase described in this composite material can be applied as they are. Therefore, it is possible to appropriately select a ceramic raw material powder having such an embodiment.
• the raw material composition can contain a sintering aid for promoting sintering.
• the sintering aid is as described above, and the content thereof is other than the metal elements of the ceramics constituting the ceramic phase of the present composite material, for example, Ca, Ba, Sr, Y, La, and the like.
• One or more metal elements selected from the group consisting of Ce, Pr, Nd, Sm, Gd, Dy, B, Si, Mn, Mg and Al are selected so as to be 1% by mass or less of the ceramic phase. can do. It is preferable not to add a sintering aid to the raw material composition. This is because there are also harmful effects due to the sintering aid.
• a known solid phase sintering method for ceramics can be used.
• any production method may be used as long as the porous sintered body is three-dimensionally connected with particles, and among them, discharge plasma firing is used.
• a method can be used.
• the discharge plasma sintering method an aggregate type porous sintered body consisting of primary particles or secondary particles can be easily obtained by heating for a short time.
• sintering is performed at a temperature lower than the melting temperature, it varies depending on the type of ceramic powder in the raw material composition, but is, for example, about 1500 ° C to 2000 ° C or less. For example, in the case of aluminum nitride, the temperature is about 1600 ° C to 1700 ° C. Further, by maintaining the heating time at a constant temperature for about several minutes to about 10 minutes, an aggregate type porous sintered body can be obtained. The pressurized state in the discharge plasma sintering method can be appropriately adjusted in order to obtain an aggregate type porous sintered body. The discharge plasma sintering method is performed under a vacuum or a nitrogen atmosphere.
• the porosity is 40% or less and the closed porosity is 3% or less. Further, according to the discharge plasma sintering method, since it is easy to manufacture an aggregate type porous sintered body, the average pore diameter of the porous sintered body varies depending on the particle size of the raw material used and the like. Can be manufactured in size.
• the resin is introduced into the pores of this porous sintered body.
• the resin itself is a liquid or is dissolved in a suitable solvent and introduced as a solution, but a solvent-free and liquid resin is preferably introduced. This is because the formation of bubbles in the resin phase due to the volatilization of the solvent can be suppressed.
• the silsesquioxane derivative is suitable because it is a liquid substance having a viscosity at 25 ° C. of 100,000 mPa ⁇ s or less.
• the resin can be introduced into the porous sintered body by spraying, coating, impregnating, etc. the resin on the porous sintered body.
• impregnation under vacuum or pressure can be used.
• vacuum impregnation it can be, for example, 1000 Pa or less, and for example, 500 Pa or less.
• the pressure impregnation for example, the pressure impregnation can be performed at 1 MPa or more and 300 MPa or less.
• the resin is a thermoplastic resin or a thermosetting resin
• the resin can be heated as necessary to improve the fluidity.
• the silsesquioxane derivative it is a liquid at room temperature, does not require heating, and can be introduced at room temperature.
• a silane coupling agent can be introduced (impregnated) on the pore surface of the porous sintered body.
• the resin is cured in a state where the resin before curing is present in the pores, for example, when the resin is introduced by impregnation, the state of being impregnated in the resin is maintained and cooling or heating is performed. Can be done. After curing in the impregnated state, the composite material can be formed into any form by cutting or the like after curing.
• thermoplastic resin it is cured by fluidizing the resin by heating or the like and then cooling it.
• the pores can be filled with the resin by heating at the time of introduction and cooling as it is.
• thermosetting resin it can be filled by introducing it into the pores and then heating it to cure it.
• the temperature required for filling the resin depends on the type of resin and the presence or absence of a cross-linking reaction catalyst. In the case of no catalyst, 100 ° C. or higher is generally preferable, and in the case of using a catalyst, the reaction temperature can be appropriately selected according to the characteristics of the catalyst. For example, when a silsesquioxane derivative having a hydrosilylation-reactive functional group is used and there is no catalyst, it is preferable to heat the derivative at a temperature of, for example, 100 ° C. or higher. This is because if the temperature is lower than 100 ° C., unreacted alkoxysilyl groups and hydrosilyl groups tend to remain.
• a cured product that has been easily heated can be obtained by heating at about 200 ° C. or higher and 300 ° C. or lower.
• the cured product can be obtained at a lower temperature (for example, room temperature to 200 ° C., preferably 50 ° C. to 150 ° C., more preferably 100 ° C. to 150 ° C.).
• the curing time in this case is usually 0.05 to 24 hours, preferably 0.1 to 5 hours.
• the temperature is 100 ° C. or higher, a cured product obtained by hydrolysis / polycondensation and hydrosilylation reaction can be sufficiently obtained.
• Examples of the catalyst for the hydrosilylation reaction include simple groups of Group 8 to Group 10 metals such as iron, cobalt, nickel, ruthenium, rhodium, palladium, iridium, and platinum, organic metal complexes, metal salts, and metal oxides. Can be mentioned. Usually, a platinum-based catalyst is used. Examples of the platinum-based catalyst include cis-PtCl 2 (PhCN) 2 , platinum carbon, a platinum complex (Pt (dbs)) coordinated with 1,3-divinyltetramethyldisiloxane, a platinum vinylmethyl cyclic siloxane complex, and platinumcarbonyl.
• a platinum complex (Pt (dbs)) coordinated with 1,3-divinyltetramethyldisiloxane, a platinum vinylmethyl cyclic siloxane complex, and a platinumcarbonyl / vinylmethylcyclicsiloxane complex are particularly preferable.
• Ph represents a phenyl group.
• the amount of the catalyst used is preferably 0.1% by mass to 1000% by mass, more preferably 0.5 to 100% by mass, and 1 to 50% by mass with respect to the amount of the silsesquioxane derivative. It is more preferably ppm.
• the resin of the present composite material is a thermosetting resin
• Such a partially cured state can be set by those skilled in the art by controlling the heating temperature, time, and the like in the thermosetting resin.
• the thermal conductivity of this composite material at 25 ° C. varies depending on the ratio of the ceramic phase and the thermal conductivity of the resin, but is, for example, 20 W / mk or more. Further, for example, it is 30 W / mk or more, and for example, 35 W / mk or more, for example, 40 W / mk or more, and for example, 45 W / mk or more.
• the density is calculated using the following formula b from the values measured by an electronic balance in air and in pure water according to Archimedes' principle.
• M represents mass.
• the specific heat was measured by using DSC (Q100 manufactured by TA Instruments) and alumina powder (AKP-30 manufactured by Sumitomo Chemical Co., Ltd.) as a standard substance at a specific heat of 0.78 (J / g ⁇ K). The measurement was performed at a temperature rise rate of 10 ° C./min for each of the empty container, standard substance, and test sample, and the difference H between the heat flow (mW) of each standard substance and test sample at 25 ° C and the heat flow of the empty container, and at the time of measurement. It can be calculated from the formula c using the mass M of.
• the thermal diffusivity was measured by a laser flash method (LFA-467 manufactured by Netzsch) at 25 ° C.
• a product (cured product) obtained by molding the present silsesquioxane derivative into 1.2 cm ⁇ 1.2 cm and a thickness of 0.5 to 1 mm is used.
• the surface of the sample is painted with carbon spray. The measurement is carried out three times per sample, and the average value can be used as the thermal diffusivity for the calculation of thermal conductivity.
• the heat resistance of this composite material can be measured as the dielectric strength by conducting a dielectric breakdown test at 200 ° C.
• the dielectric breakdown test the voltage value when a current of 10 mA or more flowed by boosting the voltage at an applied voltage of 60 Hz AC and 500 V / sec in accordance with JIS C2110-1 was defined as the dielectric breakdown voltage. Further, this dielectric breakdown voltage value was divided by the thickness of the location where the breakdown occurred in the sample to obtain the dielectric strength.
• the test was carried out in silicone oil at 200 ° C., and the electrodes were rod electrodes of 6 mm ⁇ for both electrodes.
• the composite material and the porous sintered body can be used for various purposes.
• the porous sintered body (ceramic phase) itself can be used as a carrier for resin composites that ensure thermal conductivity and heat resistance for composite materials for various purposes. Further, as described above, this composite material can constitute various heat conductive insulating elements.
• the insulating elements disclosed herein consist of or comprise the composite material.
• the three-dimensional shape of the insulating element is not particularly limited, but may be in the form of a film, a sheet, or the like. This composite material can take various three-dimensional shapes by cutting or the like, if necessary.
• the insulating element is supplied as an insulating layer or a bonding layer to the insulating portion of various electronic components to be insulated, and another layer is laminated as needed to obtain a structure.
• examples of the structure include an insulating material such as an insulating substrate, a laminated substrate, and a semiconductor device. More specifically, circuit boards, multilayer circuit boards, various power module devices, LED devices and the like can be mentioned.
• silsesquioxane derivative (Synthesis of silsesquioxane derivative)
• a silsesquioxane derivative was synthesized by the following procedure.
• the general formula and substituents of the synthesized silsesquioxane derivative are shown below.
• Aluminum nitride powder containing primary particles with an average particle size of 0.5 ⁇ m is molded into a disk shape with a diameter of 10 mm at 3 kN, and discharged plasma firing using a discharge plasma sintering device (Sumitomo Coal Mining Co., Ltd., SPS-515S).
• a discharge plasma sintering device Suditomo Coal Mining Co., Ltd., SPS-515S.
• the mixture was heated at 1600 ° C. for 5 minutes to obtain a porous sintered body (diameter 10 mm).
• this porous sintered body was immersed in an impregnation tank containing the silsesquioxane derivative synthesized in Example 1 to introduce the silsesquioxane derivative under normal temperature and reduced pressure. Then, the silsesquioxane derivative in the impregnation tank was heated at 230 ° C. for 120 minutes to cure the silsesquioxane derivative. Then, a portion corresponding to the porous sintered body was cut out from the cured silsesquioxane derivative solid to obtain the present composite material. For this composite material, the ceramic phase ratio, thermal conductivity and dielectric strength at 200 ° C. were measured.
• the same aluminum nitride powder and silsesquioxane derivative are sufficiently mixed so as to have a volume ratio of 7: 3, and while being pressurized at 60 MPa, heat-cured at 230 ° C. for 120 minutes to form a composite of Comparative Examples. Obtained the material.
• the thermal conductivity of the composite material of the comparative example was also measured.
• the sintered state the average particle diameter of the primary particles of aluminum nitride, the aspect ratio, the porosity, the ceramic phase ratio, the thermal conductivity and the insulation resistance at 200 ° C. were evaluated.
• Sintered state A cross section of the porous sintered body was observed using a scanning electron microscope. As a pretreatment for observation, a non-oxide ceramic sintered body was embedded in a resin, processed by a CP (cross section polisher) method, fixed to a sample table, and then platinum coated, and observed at 1500 times.
• CP cross section polisher
• Porosity and ratio of ceramic phase The porosity was determined by measuring the bulk density and true density of the sintered body.
• Bulk density (D) of ceramic phase mass / volume ...
• Porosity of ceramic phase (%) (1- (D / true density of ceramic phase))
• x 100 ratio of resin phase (%) ...
• Ratio of ceramic phase (%) 100-Ratio of resin phase ...
• the bulk density of the ceramic phase is measured by the volume calculated from the diameter of the disk-shaped ceramic phase (measured by calipers) and the electronic balance in accordance with the measurement method of density and specific gravity by geometric measurement of JIS Z 8807: 2012. (Refer to item 9 of JIS Z 8807: 2012).
• the true density of the ceramic phase was determined from the volume and mass of the ceramic phase measured using a dry automatic densitometer according to the method of measuring density and specific gravity by the gas substitution method of JIS Z 8807: 2012 (JIS Z 8807: See equations (14) to (17) in paragraph 11 of 2012).
• Thermal conductivity ⁇ (W / m ⁇ K) is the value of density ⁇ (g / cm 3 ), specific heat c (J / g ⁇ K), and thermal diffusion rate ⁇ (mm 2 / s).
• ⁇ ⁇ ⁇ ⁇ ⁇ c (a)
• the density was calculated using the following formula b from the values measured by an electronic balance in air and in pure water according to Archimedes' principle. The measurement was carried out at 25 ° C, and the density of pure water at 25 ° C can be found on the website of Fluid Industry Co., Ltd. (https://www.ryutai.co.jp/shiryou/liquid/water-mitsudo-1.htm). ) Is used (997.062). As the specific heat, DSC (Q100 manufactured by TA Instruments) was used, and alumina powder (AKP-30 manufactured by Sumitomo Chemical Co., Ltd.) was used as a standard substance at a specific heat of 0.78 (J / g ⁇ K).
• the measurement was performed at a temperature rise rate of 10 ° C./min for each of the empty container, standard substance, and test sample, and the difference H between the heat flow (mW) of each standard substance and test sample at 25 ° C and the heat flow of the empty container, and at the time of measurement. It was calculated from the following formula c using the mass M of.
• the thermal diffusivity was carried out by a laser flash method (LFA-467 manufactured by Netzsch) at 25 ° C. As a sample, this composite material was molded to a thickness of 1.2 cm ⁇ 1.2 cm and a thickness of 0.5 to 1 mm. In addition, the surface of the sample was painted with carbon spray in order to suppress the reflection of the laser at the time of measurement. The measurement was carried out three times per sample, and the average value was taken as the thermal diffusivity.
• Dielectric strength An insulation breakdown test was conducted at 200 ° C., and the dielectric strength was measured.
• YHTA / D-30K-2KDR manufactured by YAMABISHI was used as a control device, and the applied voltage was 60 Hz AC, 500 V / sec.
• the voltage value when the voltage was increased by 10 and a current of 10 mA or more flowed was defined as the dielectric breakdown voltage. Further, this dielectric breakdown voltage value was divided by the thickness of the location where the breakdown occurred in the sample to obtain the dielectric strength.
• the test was carried out in silicone oil at 200 ° C., and the electrodes were rod electrodes of 6 mm ⁇ for both electrodes.
• the primary particles were sintered and connected three-dimensionally, and the gap formed a pore structure.
• the average particle size was 0.5 ⁇ m as in the raw material, the shape was almost spherical, and the aspect ratio was 1.
• the primary particles to be formed had an average particle diameter of 0.5 ⁇ m, the porosity was 28% by volume, and the ratio of the ceramic phase was 72% by volume.
• the thermal conductivity at 25 ° C. was 41 W / mK, and its dielectric strength (200 ° C.) was 50 kV / mm.
• the composite material of the comparative example had a thermal conductivity of 4.5 W / mK at 25 ° C.
• the composite material of the example had high thermal conductivity, heat resistance and insulating property.

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