WO2021059647A1 - Heat dissipation sheet - Google Patents

Heat dissipation sheet Download PDF

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Publication number
WO2021059647A1
WO2021059647A1 PCT/JP2020/025718 JP2020025718W WO2021059647A1 WO 2021059647 A1 WO2021059647 A1 WO 2021059647A1 JP 2020025718 W JP2020025718 W JP 2020025718W WO 2021059647 A1 WO2021059647 A1 WO 2021059647A1
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WO
WIPO (PCT)
Prior art keywords
boron nitride
nitride particles
particles
heat radiating
radiating sheet
Prior art date
Application number
PCT/JP2020/025718
Other languages
French (fr)
Japanese (ja)
Inventor
諭司 國安
貴之 佐野
Original Assignee
富士フイルム株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 富士フイルム株式会社 filed Critical 富士フイルム株式会社
Priority to CN202080065169.9A priority Critical patent/CN114402706B/en
Priority to JP2021548352A priority patent/JP7152616B2/en
Publication of WO2021059647A1 publication Critical patent/WO2021059647A1/en

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K7/00—Constructional details common to different types of electric apparatus
    • H05K7/20—Modifications to facilitate cooling, ventilating, or heating
    • H05K7/2039—Modifications to facilitate cooling, ventilating, or heating characterised by the heat transfer by conduction from the heat generating element to a dissipating body
    • 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
    • C08K3/38—Boron-containing compounds
    • 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
    • C08K7/00—Use of ingredients characterised by shape
    • C08K7/02—Fibres or whiskers
    • C08K7/04—Fibres or whiskers inorganic
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K7/00—Constructional details common to different types of electric apparatus
    • H05K7/20—Modifications to facilitate cooling, ventilating, or heating

Definitions

  • This disclosure relates to a heat dissipation sheet.
  • Japanese Patent Application Laid-Open No. 2017-36190 describes a boron nitride agglomerated particle composition having an average particle diameter (D 50 ) of 1 ⁇ m to 200 ⁇ m, which satisfies a specific condition. Is disclosed.
  • Japanese Patent Application Laid-Open No. 2016-98301 describes a resin composition containing 30 to 60% by volume of a heat-meltable fluororesin and 40 to 70% by volume of boron nitride particles.
  • the particles (A) are composed of particles (A) and particles (B), and the particles (A) are spherical aggregate particles having an average particle size of 55 ⁇ m to 100 ⁇ m and an aspect ratio of 1 to 2, and the particles (B) are A resin composition is disclosed in which the average particle size is less than 8 to 55 ⁇ m, and the volume ratio of the particles (A) to the total amount of boron nitride is 80 to 99% by volume.
  • Japanese Patent Application Laid-Open No. 2010-174173 describes a thermally conductive pressure-sensitive adhesive composition containing boron nitride particles and an acrylic polymer component, and contains boron nitride particles having a particle size of 3 ⁇ m or more and 300 ⁇ m or less. Moreover, as for the boron nitride particles, the boron nitride particles having a particle size of 3 ⁇ m or more and 20 ⁇ m or less are 5 to 45% by volume, and the boron nitride particles having a particle size of more than 20 ⁇ m and 60 ⁇ m or less are 30 to 70% by volume and more than 60 ⁇ m.
  • a thermally conductive pressure-sensitive adhesive composition is disclosed, which comprises boron nitride particles having a particle size of 300 ⁇ m or less in a proportion of 10 to 40% by volume.
  • International Publication No. 2016/092951 discloses a resin composition containing 10 to 90% by volume of a specific hexagonal boron nitride powder.
  • compositions described in JP-A-2017-36190, JP-A-2016-98301, JP-A-2010-174173, and JP-A-2016 / 092951 are, for example, heat-dissipated by being processed into a sheet. Used as a sheet.
  • a heat radiating sheet having high thermal conductivity and high insulating properties.
  • One aspect of the present disclosure is to provide a heat radiating sheet having excellent thermal conductivity and insulating properties.
  • the present disclosure includes the following aspects. ⁇ 1>
  • the content of the boron nitride particles containing the resin binder and the boron nitride particles and having a particle size of 1 ⁇ m to 10 ⁇ m among the boron nitride particles is 40 with respect to the total number of the boron nitride particles.
  • the content of the boron nitride particles having a particle size of 20 ⁇ m to 70 ⁇ m and an aspect ratio of 1.3 or more among the boron nitride particles of% to 60% is the total number of the boron nitride particles.
  • a heat dissipation sheet that is 20% to 30%.
  • the content of the boron nitride particles having a particle size of more than 10 ⁇ m and less than 20 ⁇ m is 5% to 10% with respect to the total number of the boron nitride particles in ⁇ 1>.
  • the heat dissipation sheet described. ⁇ 3> The heat radiating sheet according to ⁇ 1>, wherein the content of the boron nitride particles having a particle size of more than 70 ⁇ m among the boron nitride particles is 10% to 30% with respect to the total number of the boron nitride particles. ..
  • the content of the boron nitride particles having a particle size of more than 10 ⁇ m and less than 20 ⁇ m is 5% or more and less than 10% with respect to the total number of the boron nitride particles.
  • the heat-dissipating sheet according to ⁇ 1>, wherein the content of the boron nitride particles having a particle size of more than 70 ⁇ m is more than 0% and 30% or less with respect to the total number of the boron nitride particles.
  • the ratio of the number of boron nitride particles having a particle size of 1 ⁇ m to 10 ⁇ m to the number of boron nitride particles having a particle size of 20 ⁇ m to 70 ⁇ m and an aspect ratio of 1.3 or more is 1.
  • the numerical range represented by using "-" means a range including the numerical values before and after "-" as the lower limit value and the upper limit value.
  • the upper limit value or the lower limit value described in a certain numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described stepwise.
  • the upper limit value or the lower limit value described in a certain numerical range may be replaced with the value shown in the examples.
  • the amount of each component in the composition means the total amount of the plurality of substances present in the composition when a plurality of substances corresponding to each component are present in the composition, unless otherwise specified. ..
  • a combination of two or more preferred embodiments is a more preferred embodiment.
  • the term “process” is included in the term “process” as long as the intended purpose of the process is achieved, not only in an independent process but also in cases where it cannot be clearly distinguished from other processes. ..
  • “% by mass” and “% by weight” are synonymous, and “parts by mass” and “parts by weight” are synonymous.
  • the “total solid content mass” means the total mass of the components excluding the solvent.
  • the heat radiating sheet according to the present disclosure contains a resin binder and boron nitride particles, and among the above-mentioned boron nitride particles, the boron nitride particles having a particle size of 1 ⁇ m to 10 ⁇ m (hereinafter referred to as “BN particles (A)”).
  • the content of the boron nitride particles is 40% to 60% with respect to the total number of the boron nitride particles, the particle size of the boron nitride particles is 20 ⁇ m to 70 ⁇ m, and the aspect ratio is 1.
  • the content of the boron nitride particles having a value of .3 or more (hereinafter, may be referred to as “BN particles (B)”) is 20% to 30% with respect to the total number of the boron nitride particles.
  • the heat radiating sheet according to the present disclosure is excellent in thermal conductivity and insulation by having the above configuration.
  • the reason why the heat radiating sheet according to the present disclosure exerts the above effect is not clear, but it is presumed as follows.
  • JP-A-2017-36190, JP-A-2016-98301, JP-A-2010-174173, and JP-A-2016 / 092951 in the process of processing the composition into a sheet, each boron nitride particle is subjected to. It is presumed that a gap is formed between them.
  • the content of boron nitride particles (that is, BN particles (A)) having a particle size of 1 ⁇ m to 10 ⁇ m is 40% to 60%, and the particle size is 20 ⁇ m.
  • the content of the boron nitride particles (that is, BN particles (B)) having an aspect ratio of about 70 ⁇ m and an aspect ratio of 1.3 or more is 20% to 30%, so that the BN particles (A) and BN It is presumed that the particles (B) are arranged so as to fill the voids with each other.
  • the ratio of the boron nitride particles to the heat radiating sheet (that is, the filling rate) can be made larger than that of the conventional heat radiating sheet. Therefore, it is presumed that the heat radiating sheet according to the present disclosure is excellent in thermal conductivity and insulation.
  • the heat radiating sheet according to the present disclosure includes a resin binder.
  • the resin binder is not limited, and a known resin binder can be used.
  • the resin binder include epoxy resin, phenol resin, polyimide resin, cresol resin, melamine resin, unsaturated polyester resin, isocyanate resin, polyurethane resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polyphenylene sulfide resin, fluororesin, and Examples include polyphenylene oxide resin.
  • the resin binder is preferably an epoxy resin from the viewpoint of having a small coefficient of thermal expansion and being excellent in heat resistance and adhesiveness.
  • the epoxy resin is not limited, and a known epoxy resin can be used.
  • examples of the epoxy resin include a bifunctional epoxy resin and a novolak type epoxy resin.
  • bifunctional epoxy resin examples include bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin.
  • novolak type epoxy resin examples include phenol novolac type epoxy resin and cresol novolak type epoxy resin.
  • the resin binder is preferably a cured product of a polymerizable monomer from the viewpoint that it is easy to add functions such as heat resistance.
  • the polymerizable monomer is not limited as long as it is a polymerizable compound, and a known polymerizable monomer can be used.
  • the polymerizable monomer preferably has a polymerizable group.
  • the polymerizable group in the polymerizable monomer at least one polymerizable group selected from the group consisting of an acryloyl group, a methacryloyl group, an oxylanyl group, and a vinyl group is preferable.
  • the polymerizable monomer may have one type of polymerizable group alone, or may have two or more types of polymerizable groups. Further, the number of polymerizable groups in the polymerizable monomer may be one or two or more. The number of polymerizable groups in the polymerizable monomer is preferably two or more, and more preferably three or more, from the viewpoint of excellent heat resistance of the cured product. The upper limit of the number of polymerizable groups in the polymerizable monomer is not limited. The number of polymerizable groups in the polymerizable monomer is often 8 or less, for example.
  • polymerizable monomer examples include epoxy compounds, phenol compounds, imide compounds, melamine compounds, isocyanate compounds, urethane compounds, acrylate compounds, and methacrylate compounds.
  • Examples of the polymerizable monomer include the epoxy resin monomer and the acrylic resin monomer described in paragraph 0028 of Japanese Patent No. 4118691, the epoxy compounds described in paragraphs 0006 to 0011 of JP2008-13759, and the special invention. Epoxy resin monomers described in paragraphs 0032 to 0100 of Japanese Patent Application Laid-Open No. 2013-227451 are also mentioned.
  • the heat radiating sheet according to the present disclosure may contain one type of resin binder alone, or may contain two or more types of resin binders.
  • the content of the resin binder may be 10% by mass to 50% by mass with respect to the total mass of the heat dissipation sheet from the viewpoint of the thermal conductivity of the heat dissipation sheet, the dispersibility of the boron nitride particles, and the film quality of the heat dissipation sheet. It is preferably 20% by mass to 50% by mass, more preferably.
  • the heat radiating sheet according to the present disclosure contains boron nitride particles.
  • the thermal conductivity of the heat radiating sheet can be improved.
  • the boron nitride particles are not limited, and known boron nitride particles can be used. Boron nitride particles are available, for example, as "HP-40MF100” manufactured by Mizushima Ferroalloy Co., Ltd.
  • Boron nitride particles may be primary particles or secondary particles (that is, aggregates of primary particles).
  • the heat radiating sheet according to the present disclosure may contain one type of boron nitride particles alone, or may contain two or more types of boron nitride particles.
  • the content of the boron nitride particles is preferably 40% by mass to 80% by mass, more preferably 45% by mass to 80% by mass, and 50% by mass to 80% by mass with respect to the total mass of the heat radiating sheet. % Is particularly preferable.
  • the content of the boron nitride particles is 40% by mass or more, the thermal conductivity of the heat radiating sheet can be improved.
  • the content of the boron nitride particles is 80% by mass or less, the film quality of the heat radiating sheet can be improved.
  • the content of the boron nitride particles is preferably 90 parts by mass to 400 parts by mass, and 100 parts by mass to 350 parts by mass with respect to 100 parts by mass of the resin binder from the viewpoint of thermal conductivity of the heat dissipation sheet. Is more preferable.
  • the boron nitride particles in the heat dissipation sheet according to the present disclosure include boron nitride particles having a particle size of 1 ⁇ m to 10 ⁇ m (that is, BN particles (A)).
  • the content of the boron nitride particles (that is, BN particles (A)) having a particle size of 1 ⁇ m to 10 ⁇ m is based on the total number of boron nitride particles. It is 40% to 60%.
  • the content of the BN particles (A) is in the above range, the thermal conductivity and the insulating property of the heat radiating sheet can be improved.
  • the content of the BN particles (A) is preferably 45% or more, more preferably 50% or more, and 55%, based on the total number of boron nitride particles, from the viewpoint of the insulating property of the heat radiating sheet.
  • the above is particularly preferable.
  • the content of the BN particles (A) is preferably 55% or less, more preferably 50% or less, and more preferably 45% or less, based on the total number of boron nitride particles, from the viewpoint of thermal conductivity of the heat dissipation sheet. It is particularly preferable that it is% or less.
  • the particle size of the boron nitride particles is the major axis of the boron nitride particles measured by the following method.
  • the heat radiating sheet is cut by irradiating with a focused ion beam (FIB).
  • FIB focused ion beam
  • the cross section of the heat dissipation sheet is observed using a scanning electron microscope (SEM), and then an image of boron nitride particles is obtained.
  • SEM scanning electron microscope
  • the "major axis of the boron nitride particle” means the length of the longest line segment among the line segments connecting arbitrary two points on the contour line of the boron nitride particle.
  • the major axis of the boron nitride particles means the diameter of the boron nitride particles.
  • the particle size distribution that is, the relationship between the particle size and the abundance ratio
  • classification can be mentioned.
  • the particle size distribution of the boron nitride particles contained in the heat-dissipating sheet according to the present disclosure can be adjusted.
  • the shape of the BN particle (A) is not limited.
  • the shape of the BN particles (A) observed in the cross section of the heat radiating sheet may be, for example, circular, elliptical, polygonal, or amorphous.
  • the boron nitride particles in the heat dissipation sheet according to the present disclosure include boron nitride particles having a particle size of 20 ⁇ m to 70 ⁇ m and an aspect ratio of 1.3 or more (that is, BN particles (B)).
  • the content of boron nitride particles (that is, BN particles (B)) having a particle size of 20 ⁇ m to 70 ⁇ m and an aspect ratio of 1.3 or more. Is 20% to 30% with respect to the total number of boron nitride particles.
  • the thermal conductivity and the insulating property of the heat radiating sheet can be improved.
  • the content of the BN particles (B) is preferably 22% or more, more preferably 25% or more, based on the total number of boron nitride particles, from the viewpoint of thermal conductivity of the heat radiating sheet.
  • the content of the BN particles (B) is preferably 28% or less, more preferably 25% or less, based on the total number of boron nitride particles, from the viewpoint of the insulating property of the heat radiating sheet.
  • the particle size of the BN particles (B) is preferably in the range of 30 ⁇ m to 70 ⁇ m.
  • the aspect ratio of the BN particles (B) is 1.3 or more.
  • the ratio of the boron nitride particles to the heat radiating sheet can be made larger than that of the conventional heat radiating sheet.
  • the upper limit of the aspect ratio of the BN particles (B) is not limited.
  • the upper limit of the aspect ratio of the BN particles (B) may be determined, for example, in the range of 10 or less.
  • the aspect ratio of the boron nitride particles is the ratio of the major axis to the minor axis (major axis / minor axis) of the boron nitride particles measured by the following method.
  • the heat radiating sheet is cut by irradiating with a focused ion beam (FIB).
  • FIB focused ion beam
  • the cross section of the heat dissipation sheet is observed using a scanning electron microscope (SEM), and then an image of boron nitride particles is obtained.
  • SEM scanning electron microscope
  • the "minor diameter of the boron nitride particle" is the most of the line segments that are orthogonal to the line segment that defines the major axis of the boron nitride particle and that connect any two points on the contour line of the boron nitride particle.
  • the shape of the BN particles (B) is not limited as long as the aspect ratio is 1.3 or more.
  • the shape of the BN particles (B) observed in the cross section of the heat radiating sheet may be, for example, elliptical, polygonal, or amorphous. Further, the BN particles (B) may be primary particles or secondary particles (that is, aggregates of primary particles).
  • the ratio of the number of BN particles (A) to the number of BN particles (B) shall be 1.5 to 3.0. Is more preferable, 1.5 to 2.5 is more preferable, 1.5 to 2.0 is further preferable, and 1.5 to 1.8 is particularly preferable.
  • the ratio of the number of BN particles (A) to the number of BN particles (B) is in the above range, the thermal conductivity of the heat radiating sheet can be improved.
  • the ratio of the number of BN particles (A) to the number of BN particles (B) is preferably 1.8 or more. More preferably, it is 2.2 or more.
  • the ratio of the number of BN particles (A) to the number of BN particles (B) is in the above range, the insulating property of the heat radiating sheet can be improved.
  • the boron nitride particles in the heat radiating sheet according to the present disclosure may include boron nitride particles having a particle size of more than 10 ⁇ m and less than 20 ⁇ m (hereinafter, may be referred to as “BN particles (C)”).
  • BN particles (C) boron nitride particles having a particle size of more than 10 ⁇ m and less than 20 ⁇ m
  • the content of the boron nitride particles (that is, BN particles (C)) having a particle size of more than 10 ⁇ m and less than 20 ⁇ m is based on the total number of boron nitride particles. It is preferably 5% to 10%, more preferably 6% to 10%, further preferably 7% to 10%, and particularly preferably 8% to 10%.
  • the content of the BN particles (C) When the content of the BN particles (C) is in the above range, the proportion of voids contained in the heat radiating sheet can be reduced.
  • the content of the BN particles (C) may be less than 10% with respect to the total number of boron nitride particles.
  • the shape of the BN particles (C) is not limited.
  • the shape of the BN particles (C) observed in the cross section of the heat radiating sheet may be, for example, circular, elliptical, polygonal, or amorphous.
  • the BN particles (C) may be primary particles or secondary particles (that is, aggregates of primary particles).
  • the content of the boron nitride particles having a particle size of more than 70 ⁇ m (hereinafter, may be referred to as “BN particles (D)”) is the total content of the boron nitride particles. With respect to the number, it is preferably more than 0% and 30% or less, more preferably 5% to 30%, further preferably 10% to 30%, and 15% to 30%. Is particularly preferable.
  • the content of the BN particles (D) is in the above range, the proportion of voids contained in the heat radiating sheet can be reduced.
  • the shape of the BN particle (D) is not limited.
  • the shape of the BN particles (D) observed in the cross section of the heat radiating sheet may be, for example, circular, elliptical, polygonal, or amorphous.
  • the BN particles (D) may be primary particles or secondary particles (that is, aggregates of primary particles).
  • the content of the boron nitride particles (that is, BN particles (C)) having a particle size of more than 10 ⁇ m and less than 20 ⁇ m is based on the total number of boron nitride particles.
  • the content of the boron nitride particles (that is, BN particles (D)) having a particle size of 5% or more and less than 10% and having a particle size of more than 70 ⁇ m exceeds 0% with respect to the total number of boron nitride particles.
  • the content of the BN particles (C) and the content of the BN particles (D) are in the above ranges, the proportion of voids contained in the heat radiating sheet can be reduced.
  • the content of the BN particles (C) and the content of the BN particles (D) are the objects, respectively. It may be determined within the range described above according to the characteristics.
  • the shape of the boron nitride particles is not limited.
  • the shape of the boron nitride particles observed in the cross section of the heat radiating sheet may be, for example, circular, elliptical, polygonal, or amorphous.
  • the average aspect ratio of the boron nitride particles is preferably 3 or more, more preferably 5 or more, and particularly preferably 8 or more. When the average aspect ratio of the boron nitride particles is 5 or more, the thermal conductivity of the heat radiating sheet can be improved.
  • the upper limit of the average aspect ratio of the boron nitride particles is not limited.
  • the average aspect ratio of the boron nitride particles is preferably 20 or less, and more preferably 15 or less, from the viewpoint of particle dispersibility in the composition described later.
  • the average aspect ratio of the boron nitride particles is obtained by arithmetically averaging the aspect ratios of 100 arbitrarily selected boron nitride particles.
  • the porosity of the heat radiating sheet according to the present disclosure is preferably 0% to 3%, more preferably 0% to 2%, and particularly preferably 0% to 1%.
  • the porosity of the heat radiating sheet according to the present disclosure is within the above range, the thermal conductivity of the heat radiating sheet can be improved. Further, as the porosity of the heat radiating sheet according to the present disclosure becomes smaller, the insulating property of the heat radiating sheet tends to be improved.
  • the porosity of the heat radiating sheet according to the present disclosure is measured by the following method. (1) Using a three-dimensional X-ray microscope (for example, "nano3DX” manufactured by Rigaku Co., Ltd.), an observation image (visual field range: 200 ⁇ m ⁇ 200 ⁇ m) of the heat dissipation sheet is obtained. (2) Arbitrary five observation images (visual field range: 200 ⁇ m ⁇ 200 ⁇ m) are binarized, and the porosity ([area of void] / [area of visual field range]) is calculated from each observation image. (3) The porosity (%) of the heat radiating sheet is calculated by arithmetically averaging the five measured values.
  • the size of the void is preferably 10 ⁇ m or less, more preferably 5 ⁇ m or less, and particularly preferably 1 ⁇ m or less. When the size of the void is 10 ⁇ m or less, the thermal conductivity of the heat radiating sheet can be significantly improved.
  • the lower limit of the size of the void is not limited, and the closer it is to 0 ⁇ m, the better.
  • the size of the void may be 0 ⁇ m or more, or may exceed 0 ⁇ m.
  • the size of the void is the diameter equivalent to an average circle obtained from the area of the void. The area of the void is measured by a method according to the above-mentioned method for measuring the porosity.
  • the thickness of the heat radiating sheet according to the present disclosure is not limited.
  • the thickness of the heat radiating sheet according to the present disclosure is preferably in the range of 50 ⁇ m to 200 ⁇ m from the viewpoint of thermal conductivity.
  • a base material may be arranged on at least one surface of the heat radiating sheet according to the present disclosure.
  • the base material include the base materials described in the section of "Manufacturing method" below.
  • the heat radiating sheet according to the present disclosure may be removed before using the heat radiating sheet, or may be used together with the heat radiating sheet.
  • the copper substrate is arranged on one side of the heat radiating sheet according to the present disclosure
  • the heat radiating sheet may be used together with the copper substrate without removing the copper substrate.
  • the base material is not included in the components of the heat radiating sheet according to the present disclosure described in each of the above sections.
  • the thickness of the heat radiating sheet according to the present disclosure described above does not include the thickness of the base material.
  • Examples of the method for producing a heat radiating sheet according to the present disclosure include a method using a composition containing a resin binder or a polymerizable monomer and boron nitride particles.
  • a heat radiating sheet can be produced by applying the above composition onto a substrate and then drying or curing it, if necessary.
  • the method for producing a heat radiating sheet according to the present disclosure includes a step of applying a composition containing a polymerizable monomer and boron nitride particles on a base material, and curing the composition applied on the base material. It is preferable to include a step.
  • a preferred method for manufacturing the heat radiating sheet according to the present disclosure will be described.
  • composition examples of the method for preparing the composition containing the polymerizable monomer and the boron nitride particles include a method of mixing the polymerizable monomer and the boron nitride particles.
  • the mixing method is not limited, and a known method can be used.
  • polymerizable monomer examples include the polymerizable monomer described in the above section "Resin binder".
  • resin binder an epoxy compound which is a kind of resin binder can be produced.
  • the composition may contain one kind of polymerizable monomer alone, or may contain two or more kinds of polymerizable monomers.
  • the content of the polymerizable monomer in the composition is preferably 10% by mass to 50% by mass, more preferably 20% by mass to 50% by mass, based on the total solid content in the composition. ..
  • the particle size distribution of the boron nitride particles so as to be within the range described in the above section "Boron nitride particles".
  • the content of each of the BN particles (A), BN particles (B), BN particles (C), and BN particles (D) can be determined by the above-mentioned "boron nitride particles" section. It can be adjusted to the range described in.
  • Examples of the method for adjusting the particle size distribution of the boron nitride particles include classification.
  • the classification method is not limited, and a known method can be used. As a method of classification, for example, sieving can be mentioned.
  • the particle size distribution of the boron nitride particles contained in the heat dissipation sheet can be adjusted by adjusting the addition amount of one or more kinds of boron nitride particles having a predetermined particle size distribution. it can.
  • the content of the boron nitride particles in the composition is preferably 40% by mass to 80% by mass, more preferably 45% by mass to 80% by mass, based on the total solid content mass in the composition. , 50% by mass to 80% by mass is particularly preferable.
  • the composition may contain other components in addition to the resin binder and the boron nitride particles.
  • Other components include, for example, curing agents, curing accelerators, polymerization initiators, and solvents.
  • the curing agent is not limited, and a known curing agent can be used.
  • the curing agent is preferably a compound having at least one functional group selected from the group consisting of a hydroxy group, an amino group, a thiol group, an isocyanate group, a carboxy group, an acryloyl group, a methacryloyl group, and a carboxylic acid anhydride group.
  • a compound having at least one functional group selected from the group consisting of a hydroxy group, an acryloyl group, a methacryloyl group, an amino group, and a thiol group is more preferable.
  • the curing agent is preferably a compound having two or more of the above functional groups, and more preferably a compound having two or three of the above functional groups.
  • the curing agent examples include amine-based curing agents, phenol-based curing agents, guanidine-based curing agents, imidazole-based curing agents, naphthol-based curing agents, acrylic-based curing agents, acid anhydride-based curing agents, and active ester-based curing agents.
  • examples thereof include a curing agent, a benzoxazine-based curing agent, and a cyanate ester-based curing agent.
  • the curing agent is preferably an imidazole-based curing agent, an acrylic-based curing agent, a phenol-based curing agent, or an amine-based curing agent.
  • the composition may contain one kind of curing agent alone, or may contain two or more kinds of curing agents.
  • the content of the curing agent is preferably 1 to 50% by mass, preferably 1% by mass to 30% by mass, based on the total solid content mass in the composition. More preferable.
  • the curing accelerator is not limited, and a known curing accelerator can be used.
  • the curing accelerator include triphenylphosphine, 2-ethyl-4-methylimidazole, boron trifluoride amine complex, and 1-benzyl-2-methylimidazole.
  • the composition may contain one kind of curing accelerator alone, or may contain two or more kinds of curing accelerators.
  • the content of the curing accelerator is preferably 0.1% by mass to 20% by mass with respect to the total solid content mass in the composition.
  • the polymerization initiator is not limited, and a known polymerization initiator can be used.
  • the polymerization initiator is the polymerization initiator described in paragraph 0062 of JP-A-2010-125782, or JP-A-2015-052710. It is preferably the polymerization initiator described in paragraph 0054.
  • the composition may contain one kind of polymerization initiator alone, or may contain two or more kinds of polymerization initiators.
  • the content of the polymerization initiator is preferably 0.1% by mass to 50% by mass with respect to the total solid content mass in the composition.
  • the solvent is not limited, and a known solvent can be used.
  • the solvent is preferably an organic solvent.
  • examples of the organic solvent include ethyl acetate, methyl ethyl ketone, dichloromethane, and tetrahydrofuran.
  • the composition may contain one kind of solvent alone, or may contain two or more kinds of solvents.
  • the content of the solvent is not limited and may be determined according to, for example, the composition of the composition and the coating method.
  • the content of the solvent is preferably 30% by mass to 80% by mass, more preferably 30% by mass to 70% by mass, based on the total mass of the composition.
  • Base material examples include a metal substrate and a release liner.
  • the metal substrate examples include an iron substrate, a copper substrate, a stainless steel substrate, an aluminum substrate, a magnesium-containing alloy substrate, and an aluminum-containing alloy substrate.
  • the metal substrate is preferably a copper substrate.
  • release liner examples include paper (for example, kraft paper, glassin paper, and high-quality paper), resin film (for example, polyolefin and polyester), and laminated paper in which paper and resin film are laminated.
  • paper for example, kraft paper, glassin paper, and high-quality paper
  • resin film for example, polyolefin and polyester
  • laminated paper in which paper and resin film are laminated.
  • polyolefins examples include polyethylene and polypropylene.
  • polyester examples include polyethylene terephthalate (PET).
  • the paper used as the peeling liner may be paper that has been peeled.
  • the peeling-treated paper can be formed, for example, by further performing a peeling treatment on one side or both sides of the sealing-treated paper.
  • the sealing treatment can be performed using, for example, clay or polyvinyl alcohol.
  • the peeling treatment can be performed using, for example, a silicone-based resin.
  • the thickness of the base material is not limited and may be determined in the range of, for example, 10 ⁇ m to 300 ⁇ m.
  • the coating method is not limited, and a known method can be used.
  • Examples of the coating method include roll coating method, gravure printing method, spin coating method, wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method, spray method, comma coating method, and blade.
  • the method and the inkjet method can be mentioned.
  • the composition applied on the base material may be dried if necessary.
  • drying method include a method in which warm air at 40 ° C. to 140 ° C. is applied to the composition coated on the substrate for 1 minute to 30 minutes.
  • the curing method is not limited, and a known method can be used.
  • the curing method is preferably a thermosetting reaction or a photocuring reaction, and preferably a thermosetting reaction.
  • the heating temperature in the thermosetting reaction is not limited and may be determined in the range of, for example, 50 ° C. to 200 ° C.
  • the heating time in the thermosetting reaction is not limited and may be determined according to the heating temperature.
  • the heating time in the thermosetting reaction may be determined, for example, in the range of 1 minute to 60 minutes.
  • the curing reaction may be a semi-curing reaction. That is, the obtained cured product may be in a so-called B stage state (semi-cured state).
  • the curing reaction may be carried out a plurality of times, if necessary.
  • the conditions of each curing reaction may be the same as or different from each other.
  • the method for manufacturing a heat radiating sheet according to the present disclosure may include steps other than the above steps (hereinafter, may be referred to as “other steps”).
  • steps other than the above steps hereinafter, may be referred to as “other steps”
  • a step of pressurizing a cured composition hereinafter, referred to as “cured product”.
  • the cured product When the base material is arranged on the surface of the cured product, the cured product may be pressurized after the base material is peeled off from the cured product. Further, the cured product may be pressed together with the base material without peeling the base material from the cured product. From the viewpoint of ease of processing, it is preferable to pressurize the cured product after peeling the base material from the cured product.
  • the pressurization method is not limited, and a known method can be used.
  • Examples of the pressurizing method include press working and calendering.
  • the pressurizing method is preferably calendar processing from the viewpoint of productivity and porosity reduction.
  • the pressure at the time of pressurization is not limited and may be determined according to, for example, the pressurization method and the composition of the cured product.
  • the pressure linear pressure
  • the pressure is preferably 50 N / m to 200 N / m, and more preferably 100 N / m to 150 N / m.
  • the temperature at the time of pressurization is not limited and may be determined according to, for example, the pressurization method and the composition of the cured product.
  • the temperature is preferably 20 ° C. to 150 ° C., more preferably 25 ° C. to 120 ° C.
  • the transport speed of the cured product is not limited.
  • the transport speed of the cured product may be determined, for example, in the range of 1 m / min to 100 m / min.
  • the heat radiating sheet according to the present disclosure is excellent in thermal conductivity and insulating property, the heat generated in the heating element can be efficiently radiated by bringing the heat radiating sheet according to the present disclosure into contact with various heating elements.
  • the heat radiating sheet according to the present disclosure by bringing the heat radiating sheet according to the present disclosure into contact with various parts constituting an electronic device, the heat generated in the above parts can be efficiently radiated.
  • the component include a power device and a CPU.
  • the heat radiating sheet according to the present disclosure may be used by arranging it between a heating element such as a power device and a heat radiating element such as a heat sink.
  • composition (A) was prepared by kneading the following components.
  • ⁇ Monomer (A) epoxy resin raw material, QE-2405, manufactured by Combiblocks
  • B epoxy resin raw material, YX4000, manufactured by Mitsubishi Chemical Co., Ltd.
  • 34 parts by mass ⁇ Methyl ethyl ketone: 65 parts by mass ⁇ TPP (triphenylphosphine, curing accelerator): 0.5 parts by mass ⁇ Boron nitride particles (A1): 51 parts by mass
  • the above-mentioned monomer (A) is a compound having the following structure.
  • the above-mentioned monomer (B) is a compound having the following structure.
  • the composition (A) was applied onto the release surface of a polyester film (NP-100A, thickness: 100 ⁇ m, manufactured by Panac Co., Ltd.) so that the thickness after drying was 250 ⁇ m. Then, a coating film was formed by drying with warm air at 130 ° C. for 5 minutes. A heat-dissipating sheet precursor with a polyester film was prepared by curing the coating film under the conditions of 180 ° C. and 1 hour. The polyester film was peeled off from the precursor of the heat-dissipating sheet with the polyester film.
  • the heat radiating sheet precursor was subjected to calendar processing under the following conditions to prepare a heat radiating sheet (thickness: 200 ⁇ m).
  • a heat radiating sheet thickness: 200 ⁇ m.
  • a pair of rolls having a rubber roll and a SUS (stainless steel) roll was used.
  • the content of the boron nitride particles in the heat radiating sheet is 50% by mass.
  • Example 2 [Classification of boron nitride particles] Boron nitride by the same method as in Example 1 except that the mixing ratio (mass ratio) of the boron nitride particles (1) and the boron nitride particles (2) used in Example 1 was changed to 1.3: 1. Particles (A2) were obtained.
  • a heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (A2).
  • Example 3 [Classification of boron nitride particles] Boron nitride by the same method as in Example 1 except that the mixing ratio (mass ratio) of the boron nitride particles (1) and the boron nitride particles (2) used in Example 1 was changed to 1.5: 1. Particles (A3) were obtained.
  • a heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (A3).
  • Example 4 [Classification of boron nitride particles] Boron nitride particles (A4) were obtained by the same method as in Example 1 except that the classification condition (D50) for obtaining the boron nitride particles (2) used in Example 1 was changed to 88 ⁇ m.
  • a heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (A4).
  • Example 5 [Classification of boron nitride particles] Boron nitride particles (A5) were obtained by the same method as in Example 1 except that the classification condition (D50) for obtaining the boron nitride particles (2) used in Example 1 was changed to 42 ⁇ m.
  • a heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (A5).
  • a heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (B1).
  • a heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (B2).
  • ⁇ Comparative example 3> [Classification of boron nitride particles]
  • the classification condition (D50) for obtaining the boron nitride particles (2) used in Example 1 was changed to 88 ⁇ m, and the boron nitride particles (1) and boron nitride particles (2) used in Example 1 were used.
  • Boron nitride particles (B3) were obtained by the same method as in Example 1 except that the mixing ratio (mass ratio) was changed to 1: 0.9.
  • a heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (B3).
  • ⁇ Comparative example 4> [Classification of boron nitride particles]
  • the classification condition (D50) for obtaining the boron nitride particles (2) used in Example 1 was changed to 42 ⁇ m, and the boron nitride particles (1) and boron nitride particles (2) used in Example 1 were used.
  • Boron nitride particles (B4) were obtained by the same method as in Example 1 except that the mixing ratio (mass ratio) was changed to 1: 1.1.
  • a heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (B4).
  • a heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (B5).
  • a heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (B6).
  • boron nitride particles Boron nitride particles (Boron Nitride (BN) powder PTX25, manufactured by MOMENTIVE) were prepared as boron nitride particles (B7).
  • the boron nitride particles (B7) were spherical primary particles.
  • a heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (B7).
  • the withstand voltage of the heat radiating sheet (sheet alone) produced in Examples and Comparative Examples was measured by the following method. In the dielectric breakdown test carried out by a method according to "JIS C 2110-1: 2016", the highest voltage at which the test piece does not cause dielectric breakdown was defined as the withstand voltage. The measurement results are shown in Table 1. The higher the withstand voltage value, the higher the insulation.
  • the thermal conductivity of the heat radiating sheet (sheet alone) produced in Examples and Comparative Examples was measured by the following method. The measurement results are shown in Table 1. The higher the thermal conductivity, the higher the thermal conductivity.
  • (2) The specific gravity of the heat radiating sheet was measured using the balance "XS204" (using the "solid specific gravity measurement kit") manufactured by METTLER TOLEDO Co., Ltd.
  • the specific heat of each heat dissipation sheet at 25 ° C. was determined using the software of DSC7 under the heating condition of 10 ° C./min.
  • (4) The thermal conductivity of the heat radiating sheet was calculated by multiplying the obtained thermal diffusivity by the specific gravity and the specific heat.
  • the content of each of the BN particles (A), BN particles (B), BN particles (C), and BN particles (D) shown in Table 1 is a ratio to the total number of boron nitride particles contained in the heat dissipation sheet. ..

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Abstract

The present disclosure provides a heat dissipation sheet comprising a resin binder and boron nitride particles. Among the boron nitride particles, those having a particle diameter of 1 μm to 10 μm account for 40% to 60% of the total number of the boron nitride particles, and among the boron nitride particles, those having a particle diameter of 20 μm to 70 μm and an aspect ratio of 1.3 or more account for 20% to 30% of the total number of the boron nitride particles.

Description

放熱シートHeat dissipation sheet
　本開示は、放熱シートに関する。 This disclosure relates to a heat dissipation sheet.
　電子機器の高性能化に伴い、電子機器を構成する種々の部品において発生した熱を効率的に放熱する必要がある。例えば、パワーデバイス、ＣＰＵ（Ｃｅｎｔｒａｌ　Ｐｒｏｃｅｓｓｉｎｇ　Ｕｎｉｔ）、又は発光ダイオード（ＬＥＤ：Ｌｉｇｈｔ　Ｅｍｉｔｔｉｎｇ　Ｄｉｏｄｅ）バックライトにおいては、１５０℃以上の熱を発するものがある。上記のような発熱体から発生した熱が電子機器の内部に蓄積すると、電子機器の誤作動等の不具合を引き起こす場合がある。このため、発熱体から発せられる熱を放熱するために種々の技術が検討されている。 With the improvement of the performance of electronic devices, it is necessary to efficiently dissipate the heat generated in various parts that make up the electronic devices. For example, some power devices, CPUs (Central Processing Units), and light emitting diode (LED: Light Emitting Diode) backlights generate heat of 150 ° C. or higher. If the heat generated from the heating element as described above accumulates inside the electronic device, it may cause a malfunction such as malfunction of the electronic device. Therefore, various techniques have been studied in order to dissipate the heat generated from the heating element.
　例えば、特開２０１７－３６１９０号公報には、平均粒子径（Ｄ５０）が１μｍ～２００μｍの窒化ホウ素凝集粒子組成物であって、特定の条件を満たすことを特徴とする窒化ホウ素凝集粒子組成物が開示されている。 For example, Japanese Patent Application Laid-Open No. 2017-36190 describes a boron nitride agglomerated particle composition having an average particle diameter (D 50 ) of 1 μm to 200 μm, which satisfies a specific condition. Is disclosed.
　例えば、特開２０１６－９８３０１号公報には、３０～６０体積％の熱溶融性フッ素樹脂と、４０～７０体積％の窒化ホウ素粒子とを含む樹脂組成物であって、上記窒化ホウ素粒子は、粒子（Ａ）及び粒子（Ｂ）から構成され、粒子（Ａ）は、平均粒径が５５μｍ～１００μｍであり、アスペクト比が１～２である球状凝集体粒子であり、粒子（Ｂ）は、平均粒径が８～５５μｍ未満の粒子であり、上記窒化ホウ素全量に対する上記粒子（Ａ）の体積比率が、８０～９９体積％であることを特徴とする樹脂組成物が開示されている。 For example, Japanese Patent Application Laid-Open No. 2016-98301 describes a resin composition containing 30 to 60% by volume of a heat-meltable fluororesin and 40 to 70% by volume of boron nitride particles. The particles (A) are composed of particles (A) and particles (B), and the particles (A) are spherical aggregate particles having an average particle size of 55 μm to 100 μm and an aspect ratio of 1 to 2, and the particles (B) are A resin composition is disclosed in which the average particle size is less than 8 to 55 μm, and the volume ratio of the particles (A) to the total amount of boron nitride is 80 to 99% by volume.
　例えば、特開２０１０－１７４１７３号公報には、窒化ホウ素粒子とアクリルポリマー成分とが含有されている熱伝導性粘着剤組成物であって、粒径３μｍ以上３００μｍ以下の窒化ホウ素粒子が含有されており、しかも、上記窒化ホウ素粒子は、３μｍ以上２０μｍ以下の粒径の窒化ホウ素粒子が５～４５体積％、２０μｍを超え６０μｍ以下の粒径の窒化ホウ素粒子が３０～７０体積％、６０μｍを超え３００μｍ以下の粒径の窒化ホウ素粒子が１０～４０体積％となる割合で含有されていることを特徴とする熱伝導性粘着剤組成物が開示されている。 For example, Japanese Patent Application Laid-Open No. 2010-174173 describes a thermally conductive pressure-sensitive adhesive composition containing boron nitride particles and an acrylic polymer component, and contains boron nitride particles having a particle size of 3 μm or more and 300 μm or less. Moreover, as for the boron nitride particles, the boron nitride particles having a particle size of 3 μm or more and 20 μm or less are 5 to 45% by volume, and the boron nitride particles having a particle size of more than 20 μm and 60 μm or less are 30 to 70% by volume and more than 60 μm. A thermally conductive pressure-sensitive adhesive composition is disclosed, which comprises boron nitride particles having a particle size of 300 μm or less in a proportion of 10 to 40% by volume.
　例えば、国際公開第２０１６／０９２９５１号には、特定の六方晶窒化ホウ素粉末を１０～９０体積％含有する、樹脂組成物が開示されている。 For example, International Publication No. 2016/092951 discloses a resin composition containing 10 to 90% by volume of a specific hexagonal boron nitride powder.
　特開２０１７－３６１９０号公報、特開２０１６－９８３０１号公報、特開２０１０－１７４１７３号公報、及び国際公開第２０１６／０９２９５１号に記載された組成物は、例えばシート状に加工されることで放熱シートとして使用される。しかしながら、上記のような従来の放熱シートによっても、十分な熱伝導性、及び絶縁性は得られない。このため、高い熱伝導性、及び高い絶縁性を有する放熱シートが求められている。 The compositions described in JP-A-2017-36190, JP-A-2016-98301, JP-A-2010-174173, and JP-A-2016 / 092951 are, for example, heat-dissipated by being processed into a sheet. Used as a sheet. However, even with the conventional heat radiating sheet as described above, sufficient thermal conductivity and insulating properties cannot be obtained. Therefore, there is a demand for a heat radiating sheet having high thermal conductivity and high insulating properties.
　本開示は、上記の事情に鑑みてなされたものである。
　本開示の一態様は、熱伝導性、及び絶縁性に優れる放熱シートを提供することを目的とする。 This disclosure has been made in view of the above circumstances.
One aspect of the present disclosure is to provide a heat radiating sheet having excellent thermal conductivity and insulating properties.
　本開示には、以下の態様が含まれる。
＜１＞　樹脂バインダーと、窒化ホウ素粒子と、を含み、上記窒化ホウ素粒子のうち、粒径が１μｍ～１０μｍである窒化ホウ素粒子の含有率が、上記窒化ホウ素粒子の全個数に対して、４０％～６０％であり、上記窒化ホウ素粒子のうち、粒径が２０μｍ～７０μｍであり、かつ、アスペクト比が１．３以上である窒化ホウ素粒子の含有率が、上記窒化ホウ素粒子の全個数に対して、２０％～３０％である放熱シート。
＜２＞　上記窒化ホウ素粒子のうち、粒径が１０μｍを超え２０μｍ未満である窒化ホウ素粒子の含有率が、上記窒化ホウ素粒子の全個数に対して、５％～１０％である＜１＞に記載の放熱シート。
＜３＞　上記窒化ホウ素粒子のうち、粒径が７０μｍを超える窒化ホウ素粒子の含有率が、上記窒化ホウ素粒子の全個数に対して、１０％～３０％である＜１＞に記載の放熱シート。
＜４＞　上記窒化ホウ素粒子のうち、粒径が１０μｍを超え２０μｍ未満である窒化ホウ素粒子の含有率が、上記窒化ホウ素粒子の全個数に対して、５％以上１０％未満であり、かつ、粒径が７０μｍを超える窒化ホウ素粒子の含有率が、上記窒化ホウ素粒子の全個数に対して、０％を超え３０％以下である＜１＞に記載の放熱シート。
＜５＞　空隙率が、０％～３％である＜１＞～＜４＞のいずれか１つに記載の放熱シート。
＜６＞　上記粒径が２０μｍ～７０μｍであり、かつ、アスペクト比が１．３以上である窒化ホウ素粒子の個数に対する、上記粒径が１μｍ～１０μｍである窒化ホウ素粒子の個数の比が、１．５～２．０である＜１＞～＜５＞のいずれか１つに記載の放熱シート。
＜７＞　上記窒化ホウ素粒子の含有率が、上記放熱シートの全質量に対して、４５質量％～８０質量％である＜１＞～＜６＞のいずれか１つに記載の放熱シート。 The present disclosure includes the following aspects.
<1> The content of the boron nitride particles containing the resin binder and the boron nitride particles and having a particle size of 1 μm to 10 μm among the boron nitride particles is 40 with respect to the total number of the boron nitride particles. The content of the boron nitride particles having a particle size of 20 μm to 70 μm and an aspect ratio of 1.3 or more among the boron nitride particles of% to 60% is the total number of the boron nitride particles. On the other hand, a heat dissipation sheet that is 20% to 30%.
<2> Among the boron nitride particles, the content of the boron nitride particles having a particle size of more than 10 μm and less than 20 μm is 5% to 10% with respect to the total number of the boron nitride particles in <1>. The heat dissipation sheet described.
<3> The heat radiating sheet according to <1>, wherein the content of the boron nitride particles having a particle size of more than 70 μm among the boron nitride particles is 10% to 30% with respect to the total number of the boron nitride particles. ..
<4> Among the boron nitride particles, the content of the boron nitride particles having a particle size of more than 10 μm and less than 20 μm is 5% or more and less than 10% with respect to the total number of the boron nitride particles. The heat-dissipating sheet according to <1>, wherein the content of the boron nitride particles having a particle size of more than 70 μm is more than 0% and 30% or less with respect to the total number of the boron nitride particles.
<5> The heat radiating sheet according to any one of <1> to <4>, which has a porosity of 0% to 3%.
<6> The ratio of the number of boron nitride particles having a particle size of 1 μm to 10 μm to the number of boron nitride particles having a particle size of 20 μm to 70 μm and an aspect ratio of 1.3 or more is 1. The heat radiating sheet according to any one of <1> to <5>, which is .5 to 2.0.
<7> The heat radiating sheet according to any one of <1> to <6>, wherein the content of the boron nitride particles is 45% by mass to 80% by mass with respect to the total mass of the heat radiating sheet.
　本開示の一態様によれば、熱伝導性、及び絶縁性に優れる放熱シートを提供することができる。 According to one aspect of the present disclosure, it is possible to provide a heat radiating sheet having excellent thermal conductivity and insulating properties.
　以下、本開示の実施形態について詳細に説明する。なお、本開示は、以下の実施形態に何ら制限されず、本開示の目的の範囲内において、適宜変更を加えて実施することができる。 Hereinafter, embodiments of the present disclosure will be described in detail. The present disclosure is not limited to the following embodiments, and can be carried out with appropriate modifications within the scope of the purpose of the present disclosure.
　本開示において、「～」を用いて表される数値範囲は、「～」の前後に記載される数値を下限値及び上限値として含む範囲を意味する。本開示に段階的に記載されている数値範囲において、ある数値範囲で記載された上限値又は下限値は、他の段階的な記載の数値範囲の上限値又は下限値に置き換えてもよい。また、本開示に記載されている数値範囲において、ある数値範囲で記載された上限値又は下限値は、実施例に示されている値に置き換えてもよい。
　本開示において、組成物中の各成分の量は、組成物中に各成分に該当する物質が複数存在する場合、特に断らない限り、組成物中に存在する複数の物質の合計量を意味する。
　本開示において、２以上の好ましい態様の組み合わせは、より好ましい態様である。
　本開示において、「工程」との用語には、独立した工程だけでなく、他の工程と明確に区別できない場合であっても工程の所期の目的が達成されれば、本用語に含まれる。
　本開示において、「質量％」と「重量％」とは同義であり、「質量部」と「重量部」とは同義である。
　本開示において、「全固形分質量」とは、溶媒を除いた成分の全質量を意味する。 In the present disclosure, the numerical range represented by using "-" means a range including the numerical values before and after "-" as the lower limit value and the upper limit value. In the numerical range described stepwise in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the upper limit value or the lower limit value of another numerical range described stepwise. Further, in the numerical range described in the present disclosure, the upper limit value or the lower limit value described in a certain numerical range may be replaced with the value shown in the examples.
In the present disclosure, the amount of each component in the composition means the total amount of the plurality of substances present in the composition when a plurality of substances corresponding to each component are present in the composition, unless otherwise specified. ..
In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment.
In the present disclosure, the term "process" is included in the term "process" as long as the intended purpose of the process is achieved, not only in an independent process but also in cases where it cannot be clearly distinguished from other processes. ..
In the present disclosure, "% by mass" and "% by weight" are synonymous, and "parts by mass" and "parts by weight" are synonymous.
In the present disclosure, the "total solid content mass" means the total mass of the components excluding the solvent.
＜放熱シート＞
　本開示に係る放熱シートは、樹脂バインダーと、窒化ホウ素粒子と、を含み、上記窒化ホウ素粒子のうち、粒径が１μｍ～１０μｍである窒化ホウ素粒子（以下、「ＢＮ粒子（Ａ）」という場合がある。）の含有率が、上記窒化ホウ素粒子の全個数に対して、４０％～６０％であり、上記窒化ホウ素粒子のうち、粒径が２０μｍ～７０μｍであり、かつ、アスペクト比が１．３以上である窒化ホウ素粒子（以下、「ＢＮ粒子（Ｂ）」という場合がある。）の含有率が、上記窒化ホウ素粒子の全個数に対して、２０％～３０％である。 <Heat dissipation sheet>
The heat radiating sheet according to the present disclosure contains a resin binder and boron nitride particles, and among the above-mentioned boron nitride particles, the boron nitride particles having a particle size of 1 μm to 10 μm (hereinafter referred to as “BN particles (A)”). The content of the boron nitride particles is 40% to 60% with respect to the total number of the boron nitride particles, the particle size of the boron nitride particles is 20 μm to 70 μm, and the aspect ratio is 1. The content of the boron nitride particles having a value of .3 or more (hereinafter, may be referred to as “BN particles (B)”) is 20% to 30% with respect to the total number of the boron nitride particles.
　本開示に係る放熱シートは、上記構成を有することで、熱伝導性、及び絶縁性に優れる。本開示に係る放熱シートが上記効果を奏する理由は明らかではないが、以下のように推察される。特開２０１７－３６１９０号公報、特開２０１６－９８３０１号公報、特開２０１０－１７４１７３号公報、及び国際公開第２０１６／０９２９５１号においては、組成物をシート状に加工する過程で各窒化ホウ素粒子の間に空隙が形成されていると推測される。一方、本開示に係る放熱シートにおいては、粒径が１μｍ～１０μｍである窒化ホウ素粒子（すなわち、ＢＮ粒子（Ａ））の含有率が、４０％～６０％であり、さらに、粒径が２０μｍ～７０μｍであり、かつ、アスペクト比が１．３以上である窒化ホウ素粒子（すなわち、ＢＮ粒子（Ｂ））の含有率が、２０％～３０％であることで、ＢＮ粒子（Ａ）とＢＮ粒子（Ｂ）とが互いに空隙を埋めるように配置されていると推察される。この結果、放熱シートに占める窒化ホウ素粒子の割合（すなわち、充填率）を従来の放熱シートよりも大きくすることができる。よって、本開示に係る放熱シートは、熱伝導性、及び絶縁性に優れると推察される。 The heat radiating sheet according to the present disclosure is excellent in thermal conductivity and insulation by having the above configuration. The reason why the heat radiating sheet according to the present disclosure exerts the above effect is not clear, but it is presumed as follows. In JP-A-2017-36190, JP-A-2016-98301, JP-A-2010-174173, and JP-A-2016 / 092951, in the process of processing the composition into a sheet, each boron nitride particle is subjected to. It is presumed that a gap is formed between them. On the other hand, in the heat radiating sheet according to the present disclosure, the content of boron nitride particles (that is, BN particles (A)) having a particle size of 1 μm to 10 μm is 40% to 60%, and the particle size is 20 μm. The content of the boron nitride particles (that is, BN particles (B)) having an aspect ratio of about 70 μm and an aspect ratio of 1.3 or more is 20% to 30%, so that the BN particles (A) and BN It is presumed that the particles (B) are arranged so as to fill the voids with each other. As a result, the ratio of the boron nitride particles to the heat radiating sheet (that is, the filling rate) can be made larger than that of the conventional heat radiating sheet. Therefore, it is presumed that the heat radiating sheet according to the present disclosure is excellent in thermal conductivity and insulation.
＜＜樹脂バインダー＞＞
　本開示に係る放熱シートは、樹脂バインダーを含む。 << Resin binder >>
The heat radiating sheet according to the present disclosure includes a resin binder.
　樹脂バインダーとしては、制限されず、公知の樹脂バインダーを利用することができる。樹脂バインダーとしては、例えば、エポキシ樹脂、フェノール樹脂、ポリイミド樹脂、クレゾール樹脂、メラミン樹脂、不飽和ポリエステル樹脂、イソシアネート樹脂、ポリウレタン樹脂、ポリブチレンテレフタレート樹脂、ポリエチレンテレフタレート樹脂、ポリフェニレンサルファイド樹脂、フッ素樹脂、及びポリフェニレンオキサイド樹脂が挙げられる。 The resin binder is not limited, and a known resin binder can be used. Examples of the resin binder include epoxy resin, phenol resin, polyimide resin, cresol resin, melamine resin, unsaturated polyester resin, isocyanate resin, polyurethane resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polyphenylene sulfide resin, fluororesin, and Examples include polyphenylene oxide resin.
　上記の中でも、樹脂バインダーは、熱膨張率が小さく、また、耐熱性、及び接着性に優れるという観点から、エポキシ樹脂であることが好ましい。 Among the above, the resin binder is preferably an epoxy resin from the viewpoint of having a small coefficient of thermal expansion and being excellent in heat resistance and adhesiveness.
　エポキシ樹脂としては、制限されず、公知のエポキシ樹脂を利用できる。エポキシ樹脂としては、例えば、二官能エポキシ樹脂、及びノボラック型エポキシ樹脂が挙げられる。 The epoxy resin is not limited, and a known epoxy resin can be used. Examples of the epoxy resin include a bifunctional epoxy resin and a novolak type epoxy resin.
　二官能エポキシ樹脂としては、例えば、ビスフェノールＡ型エポキシ樹脂、ビスフェノールＦ型エポキシ樹脂、及びビスフェノールＳ型エポキシ樹脂が挙げられる。 Examples of the bifunctional epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin.
　ノボラック型エポキシ樹脂としては、例えば、フェノールノボラック型エポキシ樹脂、及びクレゾールノボラック型エポキシ樹脂が挙げられる。 Examples of the novolak type epoxy resin include phenol novolac type epoxy resin and cresol novolak type epoxy resin.
　また、樹脂バインダーは、耐熱性等の機能を付加しやすいという観点から、重合性モノマーの硬化物であることも好ましい。 Further, the resin binder is preferably a cured product of a polymerizable monomer from the viewpoint that it is easy to add functions such as heat resistance.
　重合性モノマーとしては、重合可能な化合物であれば制限されず、公知の重合性モノマーを利用することができる。 The polymerizable monomer is not limited as long as it is a polymerizable compound, and a known polymerizable monomer can be used.
　重合性モノマーは、重合性基を有することが好ましい。重合性モノマーにおける重合性基としては、アクリロイル基、メタクリロイル基、オキシラニル基、及びビニル基からなる群より選択される少なくとも１種の重合性基が好ましい。 The polymerizable monomer preferably has a polymerizable group. As the polymerizable group in the polymerizable monomer, at least one polymerizable group selected from the group consisting of an acryloyl group, a methacryloyl group, an oxylanyl group, and a vinyl group is preferable.
　重合性モノマーは、１種単独の重合性基を有していてもよく、又は２種以上の重合性基を有していてもよい。また、重合性モノマーにおける重合性基の数は、１つであってもよく、又は２つ以上であってもよい。重合性モノマーにおける重合性基の数は、硬化物の耐熱性が優れる観点から、２つ以上であることが好ましく、３つ以上であることがより好ましい。重合性モノマーにおける重合性基の数の上限は、制限されない。重合性モノマーにおける重合性基の数は、例えば、８つ以下である場合が多い。 The polymerizable monomer may have one type of polymerizable group alone, or may have two or more types of polymerizable groups. Further, the number of polymerizable groups in the polymerizable monomer may be one or two or more. The number of polymerizable groups in the polymerizable monomer is preferably two or more, and more preferably three or more, from the viewpoint of excellent heat resistance of the cured product. The upper limit of the number of polymerizable groups in the polymerizable monomer is not limited. The number of polymerizable groups in the polymerizable monomer is often 8 or less, for example.
　具体的な重合性モノマーとしては、例えば、エポキシ化合物、フェノール化合物、イミド化合物、メラミン化合物、イソシアネート化合物、ウレタン化合物、アクリレート化合物、及びメタクリレート化合物が挙げられる。 Specific examples of the polymerizable monomer include epoxy compounds, phenol compounds, imide compounds, melamine compounds, isocyanate compounds, urethane compounds, acrylate compounds, and methacrylate compounds.
　重合性モノマーとしては、例えば、特許第４１１８６９１号公報の段落００２８に記載されたエポキシ樹脂モノマー及びアクリル樹脂モノマー、特開２００８－１３７５９号公報の段落０００６～段落００１１に記載されたエポキシ化合物、並びに特開２０１３－２２７４５１号公報の段落００３２～段落０１００に記載されたエポキシ樹脂モノマーも挙げられる。 Examples of the polymerizable monomer include the epoxy resin monomer and the acrylic resin monomer described in paragraph 0028 of Japanese Patent No. 4118691, the epoxy compounds described in paragraphs 0006 to 0011 of JP2008-13759, and the special invention. Epoxy resin monomers described in paragraphs 0032 to 0100 of Japanese Patent Application Laid-Open No. 2013-227451 are also mentioned.
　本開示に係る放熱シートは、１種単独の樹脂バインダーを含んでいてもよく、又は２種以上の樹脂バインダーを含んでいてもよい。 The heat radiating sheet according to the present disclosure may contain one type of resin binder alone, or may contain two or more types of resin binders.
　樹脂バインダーの含有率は、放熱シートの熱伝導性、窒化ホウ素粒子の分散性、及び放熱シートの膜質の観点から、放熱シートの全質量に対して、１０質量％～５０質量％であることが好ましく、２０質量％～５０質量％であることがより好ましい。 The content of the resin binder may be 10% by mass to 50% by mass with respect to the total mass of the heat dissipation sheet from the viewpoint of the thermal conductivity of the heat dissipation sheet, the dispersibility of the boron nitride particles, and the film quality of the heat dissipation sheet. It is preferably 20% by mass to 50% by mass, more preferably.
＜＜窒化ホウ素粒子＞＞
　本開示に係る放熱シートは、窒化ホウ素粒子を含む。本開示に係る放熱シートが窒化ホウ素粒子を含むことで、放熱シートの熱伝導性を向上させることができる。 << Boron Nitride Particles >>
The heat radiating sheet according to the present disclosure contains boron nitride particles. When the heat radiating sheet according to the present disclosure contains boron nitride particles, the thermal conductivity of the heat radiating sheet can be improved.
　窒化ホウ素粒子としては、制限されず、公知の窒化ホウ素粒子を利用することができる。窒化ホウ素粒子は、例えば、水島合金鉄株式会社製の「ＨＰ－４０ ＭＦ１００」として入手可能である。 The boron nitride particles are not limited, and known boron nitride particles can be used. Boron nitride particles are available, for example, as "HP-40MF100" manufactured by Mizushima Ferroalloy Co., Ltd.
　窒化ホウ素粒子は、１次粒子、又は２次粒子（すなわち、１次粒子の凝集体）であってもよい。 Boron nitride particles may be primary particles or secondary particles (that is, aggregates of primary particles).
　本開示に係る放熱シートは、１種単独の窒化ホウ素粒子を含んでいてもよく、又は２種以上の窒化ホウ素粒子を含んでいてもよい。 The heat radiating sheet according to the present disclosure may contain one type of boron nitride particles alone, or may contain two or more types of boron nitride particles.
　窒化ホウ素粒子の含有率は、放熱シートの全質量に対して、４０質量％～８０質量％であることが好ましく、４５質量％～８０質量％であることがより好ましく、５０質量％～８０質量％であることが特に好ましい。窒化ホウ素粒子の含有率が４０質量％以上であることで、放熱シートの熱伝導性を向上させることができる。窒化ホウ素粒子の含有率が８０質量％以下であることで、放熱シートの膜質を向上させることができる。 The content of the boron nitride particles is preferably 40% by mass to 80% by mass, more preferably 45% by mass to 80% by mass, and 50% by mass to 80% by mass with respect to the total mass of the heat radiating sheet. % Is particularly preferable. When the content of the boron nitride particles is 40% by mass or more, the thermal conductivity of the heat radiating sheet can be improved. When the content of the boron nitride particles is 80% by mass or less, the film quality of the heat radiating sheet can be improved.
　窒化ホウ素粒子の含有率は、放熱シートの熱伝導性の観点から、樹脂バインダー１００質量部に対して、９０質量部～４００質量部であることが好ましく、１００質量部～３５０質量部であることがより好ましい。 The content of the boron nitride particles is preferably 90 parts by mass to 400 parts by mass, and 100 parts by mass to 350 parts by mass with respect to 100 parts by mass of the resin binder from the viewpoint of thermal conductivity of the heat dissipation sheet. Is more preferable.
　本開示に係る放熱シートにおける窒化ホウ素粒子は、粒径が１μｍ～１０μｍである窒化ホウ素粒子（すなわち、ＢＮ粒子（Ａ））を含む。本開示に係る放熱シートに含まれる窒化ホウ素粒子のうち、粒径が１μｍ～１０μｍである窒化ホウ素粒子（すなわち、ＢＮ粒子（Ａ））の含有率は、窒化ホウ素粒子の全個数に対して、４０％～６０％である。ＢＮ粒子（Ａ）の含有率が上記範囲であることで、放熱シートの熱伝導性、及び絶縁性を向上させることができる。 The boron nitride particles in the heat dissipation sheet according to the present disclosure include boron nitride particles having a particle size of 1 μm to 10 μm (that is, BN particles (A)). Among the boron nitride particles contained in the heat dissipation sheet according to the present disclosure, the content of the boron nitride particles (that is, BN particles (A)) having a particle size of 1 μm to 10 μm is based on the total number of boron nitride particles. It is 40% to 60%. When the content of the BN particles (A) is in the above range, the thermal conductivity and the insulating property of the heat radiating sheet can be improved.
　ＢＮ粒子（Ａ）の含有率は、放熱シートの絶縁性の観点から、窒化ホウ素粒子の全個数に対して、４５％以上であることが好ましく、５０％以上であることがより好ましく、５５％以上であることが特に好ましい。 The content of the BN particles (A) is preferably 45% or more, more preferably 50% or more, and 55%, based on the total number of boron nitride particles, from the viewpoint of the insulating property of the heat radiating sheet. The above is particularly preferable.
　ＢＮ粒子（Ａ）の含有率は、放熱シートの熱伝導性の観点から、窒化ホウ素粒子の全個数に対して、５５％以下であることが好ましく、５０％以下であることがより好ましく、４５％以下であることが特に好ましい。 The content of the BN particles (A) is preferably 55% or less, more preferably 50% or less, and more preferably 45% or less, based on the total number of boron nitride particles, from the viewpoint of thermal conductivity of the heat dissipation sheet. It is particularly preferable that it is% or less.
　本開示において、窒化ホウ素粒子の粒径は、以下の方法によって測定される窒化ホウ素粒子の長径である。
　（１）収束イオンビーム（ＦＩＢ）を照射することにより、放熱シートを切断する。
　（２）走査型電子顕微鏡（ＳＥＭ）を用いて放熱シートの断面を観察し、次いで、窒化ホウ素粒子の画像を得る。
　（３）窒化ホウ素粒子の長径を測定する。ここで、「窒化ホウ素粒子の長径」とは、窒化ホウ素粒子の輪郭線上の任意の２点間を結ぶ線分のうち、最も長い線分の長さをいう。例えば、上記画像において観察される窒化ホウ素粒子が真円である場合、窒化ホウ素粒子の長径とは、窒化ホウ素粒子の直径をいう。 In the present disclosure, the particle size of the boron nitride particles is the major axis of the boron nitride particles measured by the following method.
(1) The heat radiating sheet is cut by irradiating with a focused ion beam (FIB).
(2) The cross section of the heat dissipation sheet is observed using a scanning electron microscope (SEM), and then an image of boron nitride particles is obtained.
(3) Measure the major axis of the boron nitride particles. Here, the "major axis of the boron nitride particle" means the length of the longest line segment among the line segments connecting arbitrary two points on the contour line of the boron nitride particle. For example, when the boron nitride particles observed in the above image are perfect circles, the major axis of the boron nitride particles means the diameter of the boron nitride particles.
　本開示に係る放熱シートに含まれる窒化ホウ素粒子の粒度分布（すなわち、粒径と存在比率との関係）を調節する方法としては、例えば、分級が挙げられる。例えば、分級によって粒度分布を調節した窒化ホウ素粒子を用いて放熱シートを製造することで、本開示に係る放熱シートに含まれる窒化ホウ素粒子の粒度分布を調節することができる。 As a method for adjusting the particle size distribution (that is, the relationship between the particle size and the abundance ratio) of the boron nitride particles contained in the heat radiating sheet according to the present disclosure, for example, classification can be mentioned. For example, by manufacturing a heat-dissipating sheet using boron nitride particles whose particle size distribution has been adjusted by classification, the particle size distribution of the boron nitride particles contained in the heat-dissipating sheet according to the present disclosure can be adjusted.
　ＢＮ粒子（Ａ）の形状は、制限されない。放熱シートの断面で観察されるＢＮ粒子（Ａ）の形状は、例えば、円形、楕円形、多角形、又は不定形であってもよい。 The shape of the BN particle (A) is not limited. The shape of the BN particles (A) observed in the cross section of the heat radiating sheet may be, for example, circular, elliptical, polygonal, or amorphous.
　本開示に係る放熱シートにおける窒化ホウ素粒子は、粒径が２０μｍ～７０μｍであり、かつ、アスペクト比が１．３以上である窒化ホウ素粒子（すなわち、ＢＮ粒子（Ｂ））を含む。本開示に係る放熱シートに含まれる窒化ホウ素粒子のうち、粒径が２０μｍ～７０μｍであり、かつ、アスペクト比が１．３以上である窒化ホウ素粒子（すなわち、ＢＮ粒子（Ｂ））の含有率は、窒化ホウ素粒子の全個数に対して、２０％～３０％である。ＢＮ粒子（Ｂ）の含有率が上記範囲であることで、放熱シートの熱伝導性、及び絶縁性を向上させることができる。 The boron nitride particles in the heat dissipation sheet according to the present disclosure include boron nitride particles having a particle size of 20 μm to 70 μm and an aspect ratio of 1.3 or more (that is, BN particles (B)). Among the boron nitride particles contained in the heat dissipation sheet according to the present disclosure, the content of boron nitride particles (that is, BN particles (B)) having a particle size of 20 μm to 70 μm and an aspect ratio of 1.3 or more. Is 20% to 30% with respect to the total number of boron nitride particles. When the content of the BN particles (B) is in the above range, the thermal conductivity and the insulating property of the heat radiating sheet can be improved.
　ＢＮ粒子（Ｂ）の含有率は、放熱シートの熱伝導性の観点から、窒化ホウ素粒子の全個数に対して、２２％以上であることが好ましく、２５％以上であることがより好ましい。 The content of the BN particles (B) is preferably 22% or more, more preferably 25% or more, based on the total number of boron nitride particles, from the viewpoint of thermal conductivity of the heat radiating sheet.
　ＢＮ粒子（Ｂ）の含有率は、放熱シートの絶縁性の観点から、窒化ホウ素粒子の全個数に対して、２８％以下であることが好ましく、２５％以下であることがより好ましい。 The content of the BN particles (B) is preferably 28% or less, more preferably 25% or less, based on the total number of boron nitride particles, from the viewpoint of the insulating property of the heat radiating sheet.
　ＢＮ粒子（Ｂ）の粒径は、３０μｍ～７０μｍの範囲であることが好ましい。 The particle size of the BN particles (B) is preferably in the range of 30 μm to 70 μm.
　ＢＮ粒子（Ｂ）のアスペクト比は、１．３以上である。ＢＮ粒子（Ｂ）のアスペクト比が１．３以上であることで、放熱シートに占める窒化ホウ素粒子の割合を従来の放熱シートよりも大きくすることができる。ＢＮ粒子（Ｂ）のアスペクト比の上限は、制限されない。ＢＮ粒子（Ｂ）のアスペクト比の上限は、例えば、１０以下の範囲で決定すればよい。 The aspect ratio of the BN particles (B) is 1.3 or more. When the aspect ratio of the BN particles (B) is 1.3 or more, the ratio of the boron nitride particles to the heat radiating sheet can be made larger than that of the conventional heat radiating sheet. The upper limit of the aspect ratio of the BN particles (B) is not limited. The upper limit of the aspect ratio of the BN particles (B) may be determined, for example, in the range of 10 or less.
　本開示において、窒化ホウ素粒子のアスペクト比は、以下の方法によって測定される窒化ホウ素粒子の短径に対する長径の比（長径／短径）である。
　（１）収束イオンビーム（ＦＩＢ）を照射することにより、放熱シートを切断する。
　（２）走査型電子顕微鏡（ＳＥＭ）を用いて放熱シートの断面を観察し、次いで、窒化ホウ素粒子の画像を得る。
　（３）窒化ホウ素粒子の長径及び短径をそれぞれ測定する。ここで、「窒化ホウ素粒子の短径」とは、窒化ホウ素粒子の長径を規定する線分に直交し、かつ、窒化ホウ素粒子の輪郭線上の任意の２点間を結ぶ線分のうち、最も長い線分の長さをいう。
　（４）窒化ホウ素粒子の短径に対する長径の比（長径／短径）を求める。 In the present disclosure, the aspect ratio of the boron nitride particles is the ratio of the major axis to the minor axis (major axis / minor axis) of the boron nitride particles measured by the following method.
(1) The heat radiating sheet is cut by irradiating with a focused ion beam (FIB).
(2) The cross section of the heat dissipation sheet is observed using a scanning electron microscope (SEM), and then an image of boron nitride particles is obtained.
(3) Measure the major axis and the minor axis of the boron nitride particles, respectively. Here, the "minor diameter of the boron nitride particle" is the most of the line segments that are orthogonal to the line segment that defines the major axis of the boron nitride particle and that connect any two points on the contour line of the boron nitride particle. The length of a long line segment.
(4) Obtain the ratio (major axis / minor axis) of the major axis to the minor axis of the boron nitride particles.
　ＢＮ粒子（Ｂ）の形状は、アスペクト比が１．３以上となる形状であれば、制限されない。放熱シートの断面で観察されるＢＮ粒子（Ｂ）の形状は、例えば、楕円形、多角形、又は不定形であってもよい。また、ＢＮ粒子（Ｂ）は、１次粒子、又は２次粒子（すなわち、１次粒子の凝集体）であってもよい。 The shape of the BN particles (B) is not limited as long as the aspect ratio is 1.3 or more. The shape of the BN particles (B) observed in the cross section of the heat radiating sheet may be, for example, elliptical, polygonal, or amorphous. Further, the BN particles (B) may be primary particles or secondary particles (that is, aggregates of primary particles).
　ＢＮ粒子（Ｂ）の個数に対するＢＮ粒子（Ａ）の個数の比（［ＢＮ粒子（Ａ）の個数］／［ＢＮ粒子（Ｂ）の個数］）は、１．５～３．０であることが好ましく、１．５～２．５であることがより好ましく、１．５～２．０であることがさらに好ましく、１．５～１．８であることが特に好ましい。ＢＮ粒子（Ｂ）の個数に対するＢＮ粒子（Ａ）の個数の比が上記範囲であることで、放熱シートの熱伝導性を向上させることができる。 The ratio of the number of BN particles (A) to the number of BN particles (B) ([number of BN particles (A)] / [number of BN particles (B)]) shall be 1.5 to 3.0. Is more preferable, 1.5 to 2.5 is more preferable, 1.5 to 2.0 is further preferable, and 1.5 to 1.8 is particularly preferable. When the ratio of the number of BN particles (A) to the number of BN particles (B) is in the above range, the thermal conductivity of the heat radiating sheet can be improved.
　ＢＮ粒子（Ｂ）の個数に対するＢＮ粒子（Ａ）の個数の比（［ＢＮ粒子（Ａ）の個数］／［ＢＮ粒子（Ｂ）の個数］）は、１．８以上であることが好ましく、２．２以上であることがより好ましい。ＢＮ粒子（Ｂ）の個数に対するＢＮ粒子（Ａ）の個数の比が上記範囲であることで、放熱シートの絶縁性を向上させることができる。 The ratio of the number of BN particles (A) to the number of BN particles (B) ([number of BN particles (A)] / [number of BN particles (B)]) is preferably 1.8 or more. More preferably, it is 2.2 or more. When the ratio of the number of BN particles (A) to the number of BN particles (B) is in the above range, the insulating property of the heat radiating sheet can be improved.
　本開示に係る放熱シートにおける窒化ホウ素粒子は、粒径が１０μｍを超え２０μｍ未満である窒化ホウ素粒子（以下、「ＢＮ粒子（Ｃ）」という場合がある。）を含んでもよい。本開示に係る放熱シートに含まれる窒化ホウ素粒子のうち、粒径が１０μｍを超え２０μｍ未満である窒化ホウ素粒子（すなわち、ＢＮ粒子（Ｃ））の含有率は、窒化ホウ素粒子の全個数に対して、５％～１０％であることが好ましく、６％～１０％であることがより好ましく、７％～１０％であることがさらに好ましく、８％～１０％であることが特に好ましい。ＢＮ粒子（Ｃ）の含有率が上記範囲であることで、放熱シートに含まれる空隙の割合を減らすことができる。ＢＮ粒子（Ｃ）の含有率は、窒化ホウ素粒子の全個数に対して、１０％未満であってもよい。 The boron nitride particles in the heat radiating sheet according to the present disclosure may include boron nitride particles having a particle size of more than 10 μm and less than 20 μm (hereinafter, may be referred to as “BN particles (C)”). Among the boron nitride particles contained in the heat dissipation sheet according to the present disclosure, the content of the boron nitride particles (that is, BN particles (C)) having a particle size of more than 10 μm and less than 20 μm is based on the total number of boron nitride particles. It is preferably 5% to 10%, more preferably 6% to 10%, further preferably 7% to 10%, and particularly preferably 8% to 10%. When the content of the BN particles (C) is in the above range, the proportion of voids contained in the heat radiating sheet can be reduced. The content of the BN particles (C) may be less than 10% with respect to the total number of boron nitride particles.
　ＢＮ粒子（Ｃ）の形状は、制限されない。放熱シートの断面で観察されるＢＮ粒子（Ｃ）の形状は、例えば、円形、楕円形、多角形、又は不定形であってもよい。また、ＢＮ粒子（Ｃ）は、１次粒子、又は２次粒子（すなわち、１次粒子の凝集体）であってもよい。 The shape of the BN particles (C) is not limited. The shape of the BN particles (C) observed in the cross section of the heat radiating sheet may be, for example, circular, elliptical, polygonal, or amorphous. Further, the BN particles (C) may be primary particles or secondary particles (that is, aggregates of primary particles).
　本開示に係る放熱シートに含まれる窒化ホウ素粒子のうち、粒径が７０μｍを超える窒化ホウ素粒子（以下、「ＢＮ粒子（Ｄ）」という場合がある。）の含有率は、窒化ホウ素粒子の全個数に対して、０％を超え３０％以下であることが好ましく、５％～３０％であることがより好ましく、１０％～３０％であることがさらに好ましく、１５％～３０％であることが特に好ましい。ＢＮ粒子（Ｄ）の含有率が上記範囲であることで、放熱シートに含まれる空隙の割合を減らすことができる。 Among the boron nitride particles contained in the heat radiating sheet according to the present disclosure, the content of the boron nitride particles having a particle size of more than 70 μm (hereinafter, may be referred to as “BN particles (D)”) is the total content of the boron nitride particles. With respect to the number, it is preferably more than 0% and 30% or less, more preferably 5% to 30%, further preferably 10% to 30%, and 15% to 30%. Is particularly preferable. When the content of the BN particles (D) is in the above range, the proportion of voids contained in the heat radiating sheet can be reduced.
　ＢＮ粒子（Ｄ）の形状は、制限されない。放熱シートの断面で観察されるＢＮ粒子（Ｄ）の形状は、例えば、円形、楕円形、多角形、又は不定形であってもよい。また、ＢＮ粒子（Ｄ）は、１次粒子、又は２次粒子（すなわち、１次粒子の凝集体）であってもよい。 The shape of the BN particle (D) is not limited. The shape of the BN particles (D) observed in the cross section of the heat radiating sheet may be, for example, circular, elliptical, polygonal, or amorphous. Further, the BN particles (D) may be primary particles or secondary particles (that is, aggregates of primary particles).
　次に、ＢＮ粒子（Ｃ）の含有率とＢＮ粒子（Ｄ）の含有率との好ましい関係について説明する。本開示に係る放熱シートに含まれる窒化ホウ素粒子のうち、粒径が１０μｍを超え２０μｍ未満である窒化ホウ素粒子（すなわち、ＢＮ粒子（Ｃ））の含有率は、窒化ホウ素粒子の全個数に対して、５％以上１０％未満であり、かつ、粒径が７０μｍを超える窒化ホウ素粒子（すなわち、ＢＮ粒子（Ｄ））の含有率は、窒化ホウ素粒子の全個数に対して、０％を超え３０％以下であることが好ましい。ＢＮ粒子（Ｃ）の含有率、及びＢＮ粒子（Ｄ）の含有率がそれぞれ上記範囲であることで、放熱シートに含まれる空隙の割合を減らすことができる。上記したＢＮ粒子（Ｃ）の含有率とＢＮ粒子（Ｄ）の含有率との好ましい関係において、ＢＮ粒子（Ｃ）の含有率、及びＢＮ粒子（Ｄ）の含有率は、それぞれ、目的とする特性に応じて既述の範囲で決定すればよい。 Next, the preferable relationship between the content of the BN particles (C) and the content of the BN particles (D) will be described. Among the boron nitride particles contained in the heat radiation sheet according to the present disclosure, the content of the boron nitride particles (that is, BN particles (C)) having a particle size of more than 10 μm and less than 20 μm is based on the total number of boron nitride particles. The content of the boron nitride particles (that is, BN particles (D)) having a particle size of 5% or more and less than 10% and having a particle size of more than 70 μm exceeds 0% with respect to the total number of boron nitride particles. It is preferably 30% or less. When the content of the BN particles (C) and the content of the BN particles (D) are in the above ranges, the proportion of voids contained in the heat radiating sheet can be reduced. In the preferable relationship between the content of the BN particles (C) and the content of the BN particles (D) described above, the content of the BN particles (C) and the content of the BN particles (D) are the objects, respectively. It may be determined within the range described above according to the characteristics.
　窒化ホウ素粒子の形状は、制限されない。放熱シートの断面で観察される窒化ホウ素粒子の形状は、例えば、円形、楕円形、多角形、又は不定形であってもよい。 The shape of the boron nitride particles is not limited. The shape of the boron nitride particles observed in the cross section of the heat radiating sheet may be, for example, circular, elliptical, polygonal, or amorphous.
　窒化ホウ素粒子の平均アスペクト比は、３以上であることが好ましく、５以上であることがより好ましく、８以上であることが特に好ましい。窒化ホウ素粒子の平均アスペクト比が５以上であることで、放熱シートの熱伝導性を向上させることができる。窒化ホウ素粒子の平均アスペクト比の上限は、制限されない。窒化ホウ素粒子の平均アスペクト比は、後述する組成物における粒子分散性の観点から、２０以下であることが好ましく、１５以下であることがより好ましい。窒化ホウ素粒子の平均アスペクト比は、任意に選択される１００個の窒化ホウ素粒子のアスペクト比を算術平均することによって求める。 The average aspect ratio of the boron nitride particles is preferably 3 or more, more preferably 5 or more, and particularly preferably 8 or more. When the average aspect ratio of the boron nitride particles is 5 or more, the thermal conductivity of the heat radiating sheet can be improved. The upper limit of the average aspect ratio of the boron nitride particles is not limited. The average aspect ratio of the boron nitride particles is preferably 20 or less, and more preferably 15 or less, from the viewpoint of particle dispersibility in the composition described later. The average aspect ratio of the boron nitride particles is obtained by arithmetically averaging the aspect ratios of 100 arbitrarily selected boron nitride particles.
＜＜空隙率＞＞
　本開示に係る放熱シートの空隙率は、０％～３％であることが好ましく、０％～２％であることがより好ましく、０％～１％であることが特に好ましい。本開示に係る放熱シートの空隙率が上記範囲であることで、放熱シートの熱伝導性を向上させることができる。また、本開示に係る放熱シートの空隙率が小さくなるにしたがって、放熱シートの絶縁性も向上する傾向にある。 << Porosity >>
The porosity of the heat radiating sheet according to the present disclosure is preferably 0% to 3%, more preferably 0% to 2%, and particularly preferably 0% to 1%. When the porosity of the heat radiating sheet according to the present disclosure is within the above range, the thermal conductivity of the heat radiating sheet can be improved. Further, as the porosity of the heat radiating sheet according to the present disclosure becomes smaller, the insulating property of the heat radiating sheet tends to be improved.
　本開示に係る放熱シートの空隙率は、以下の方法によって測定する。
　（１）３次元Ｘ線顕微鏡（例えば、株式会社リガク製の「ｎａｎｏ３ＤＸ」）を用いて、放熱シートの観察像（視野範囲：２００μｍ×２００μｍ）を得る。
　（２）任意の５つの観察像（視野範囲：２００μｍ×２００μｍ）を二値化処理し、各観察像から空隙率（［空隙の面積］／［視野範囲の面積］）を算出する。
　（３）５つの測定値を算術平均することによって、放熱シートの空隙率（％）を算出する。 The porosity of the heat radiating sheet according to the present disclosure is measured by the following method.
(1) Using a three-dimensional X-ray microscope (for example, "nano3DX" manufactured by Rigaku Co., Ltd.), an observation image (visual field range: 200 μm × 200 μm) of the heat dissipation sheet is obtained.
(2) Arbitrary five observation images (visual field range: 200 μm × 200 μm) are binarized, and the porosity ([area of void] / [area of visual field range]) is calculated from each observation image.
(3) The porosity (%) of the heat radiating sheet is calculated by arithmetically averaging the five measured values.
＜＜空隙の大きさ＞＞
　空隙の大きさは、１０μｍ以下であることが好ましく、５μｍ以下であることがより好ましく、１μｍ以下であることが特に好ましい。空隙の大きさが１０μｍ以下であることで、放熱シートの熱伝導性を大幅に向上させることができる。空隙の大きさの下限は、制限されず、０μｍに近いほどよい。空隙の大きさは、０μｍ以上、又は０μｍを超えていてもよい。空隙の大きさは、空隙の面積から求めた平均円相当径である。空隙の面積は、上記空隙率の測定方法に準ずる方法によって測定する。 << Size of void >>
The size of the void is preferably 10 μm or less, more preferably 5 μm or less, and particularly preferably 1 μm or less. When the size of the void is 10 μm or less, the thermal conductivity of the heat radiating sheet can be significantly improved. The lower limit of the size of the void is not limited, and the closer it is to 0 μm, the better. The size of the void may be 0 μm or more, or may exceed 0 μm. The size of the void is the diameter equivalent to an average circle obtained from the area of the void. The area of the void is measured by a method according to the above-mentioned method for measuring the porosity.
＜＜厚さ＞＞
　本開示に係る放熱シートの厚さは、制限されない。本開示に係る放熱シートの厚さは、熱伝導性の観点から、５０μｍ～２００μｍの範囲内であることが好ましい。 << Thickness >>
The thickness of the heat radiating sheet according to the present disclosure is not limited. The thickness of the heat radiating sheet according to the present disclosure is preferably in the range of 50 μm to 200 μm from the viewpoint of thermal conductivity.
＜＜他の部材＞＞
　本開示に係る放熱シートの少なくとも一方の面に、基材が配置されていてもよい。基材としては、下記「製造方法」の項において説明する基材が挙げられる。本開示に係る放熱シートを使用する場合、基材は、放熱シートを使用する前に除去してもよく、又は放熱シートと共に使用してもよい。例えば、本開示に係る放熱シートの片面に銅基板が配置されている場合、銅基板を除去することなく、銅基板と共に放熱シートを使用してもよい。ただし、基材は、上記各項において説明した本開示に係る放熱シートの構成要素には含まれない。例えば、上記した本開示に係る放熱シートの厚さには、基材の厚さは含まれない。 << Other members >>
A base material may be arranged on at least one surface of the heat radiating sheet according to the present disclosure. Examples of the base material include the base materials described in the section of "Manufacturing method" below. When the heat radiating sheet according to the present disclosure is used, the base material may be removed before using the heat radiating sheet, or may be used together with the heat radiating sheet. For example, when the copper substrate is arranged on one side of the heat radiating sheet according to the present disclosure, the heat radiating sheet may be used together with the copper substrate without removing the copper substrate. However, the base material is not included in the components of the heat radiating sheet according to the present disclosure described in each of the above sections. For example, the thickness of the heat radiating sheet according to the present disclosure described above does not include the thickness of the base material.
＜＜製造方法＞＞
　本開示に係る放熱シートの製造方法としては、例えば、樹脂バインダー又は重合性モノマーと、窒化ホウ素粒子と、を含む組成物を用いる方法が挙げられる。例えば、上記組成物を基材上に塗布し、次いで、必要に応じて乾燥又は硬化させることによって放熱シートを製造することができる。本開示に係る放熱シートの製造方法は、基材上に、重合性モノマーと、窒化ホウ素粒子と、を含む組成物を塗布する工程と、上記基材上に塗布された上記組成物を硬化させる工程と、を含むことが好ましい。以下、本開示に係る放熱シートの好ましい製造方法について説明する。 << Manufacturing method >>
Examples of the method for producing a heat radiating sheet according to the present disclosure include a method using a composition containing a resin binder or a polymerizable monomer and boron nitride particles. For example, a heat radiating sheet can be produced by applying the above composition onto a substrate and then drying or curing it, if necessary. The method for producing a heat radiating sheet according to the present disclosure includes a step of applying a composition containing a polymerizable monomer and boron nitride particles on a base material, and curing the composition applied on the base material. It is preferable to include a step. Hereinafter, a preferred method for manufacturing the heat radiating sheet according to the present disclosure will be described.
［組成物］
　重合性モノマーと、窒化ホウ素粒子と、を含む組成物の調製方法としては、例えば、重合性モノマーと窒化ホウ素粒子とを混合する方法が挙げられる。混合方法としては、制限されず、公知の方法を利用することができる。 [Composition]
Examples of the method for preparing the composition containing the polymerizable monomer and the boron nitride particles include a method of mixing the polymerizable monomer and the boron nitride particles. The mixing method is not limited, and a known method can be used.
　重合性モノマーとしては、例えば、上記「樹脂バインダー」の項において説明した重合性モノマーが挙げられる。例えば、重合性モノマーとして、エポキシ化合物、及びフェノール化合物を用いることで、樹脂バインダーの一種であるエポキシ樹脂を製造することができる。 Examples of the polymerizable monomer include the polymerizable monomer described in the above section "Resin binder". For example, by using an epoxy compound and a phenol compound as the polymerizable monomer, an epoxy resin which is a kind of resin binder can be produced.
　組成物は、１種単独の重合性モノマーを含んでいてもよく、又は２種以上の重合性モノマーを含んでいてもよい。 The composition may contain one kind of polymerizable monomer alone, or may contain two or more kinds of polymerizable monomers.
　組成物中の重合性モノマーの含有率は、組成物中の全固形分質量に対して、１０質量％～５０質量％であることが好ましく、２０質量％～５０質量％であることがより好ましい。 The content of the polymerizable monomer in the composition is preferably 10% by mass to 50% by mass, more preferably 20% by mass to 50% by mass, based on the total solid content in the composition. ..
　窒化ホウ素粒子の粒度分布は、上記「窒化ホウ素粒子」の項において説明した範囲となるように調節することが好ましい。窒化ホウ素粒子の粒度分布を調節することで、ＢＮ粒子（Ａ）、ＢＮ粒子（Ｂ）、ＢＮ粒子（Ｃ）、及びＢＮ粒子（Ｄ）の各含有率を、上記「窒化ホウ素粒子」の項において説明した範囲に調節することができる。窒化ホウ素粒子の粒度分布を調節する方法としては、例えば、分級が挙げられる。分級の方法としては、制限されず、公知の方法を利用することができる。分級の方法としては、例えば、ふるい分けが挙げられる。組成物の調製においては、例えば、所定の粒度分布を有する１種又は２種以上の窒化ホウ素粒子の添加量を調節することで、放熱シートに含まれる窒化ホウ素粒子の粒度分布を調節することができる。 It is preferable to adjust the particle size distribution of the boron nitride particles so as to be within the range described in the above section "Boron nitride particles". By adjusting the particle size distribution of the boron nitride particles, the content of each of the BN particles (A), BN particles (B), BN particles (C), and BN particles (D) can be determined by the above-mentioned "boron nitride particles" section. It can be adjusted to the range described in. Examples of the method for adjusting the particle size distribution of the boron nitride particles include classification. The classification method is not limited, and a known method can be used. As a method of classification, for example, sieving can be mentioned. In the preparation of the composition, for example, the particle size distribution of the boron nitride particles contained in the heat dissipation sheet can be adjusted by adjusting the addition amount of one or more kinds of boron nitride particles having a predetermined particle size distribution. it can.
　組成物中の窒化ホウ素粒子の含有率は、組成物中の全固形分質量に対して、４０質量％～８０質量％であることが好ましく、４５質量％～８０質量％であることがより好ましく、５０質量％～８０質量％であることが特に好ましい。 The content of the boron nitride particles in the composition is preferably 40% by mass to 80% by mass, more preferably 45% by mass to 80% by mass, based on the total solid content mass in the composition. , 50% by mass to 80% by mass is particularly preferable.
　組成物は、樹脂バインダー、及び窒化ホウ素粒子に加えて、他の成分を含有していてもよい。他の成分としては、例えば、硬化剤、硬化促進剤、重合開始剤、及び溶媒が挙げられる。 The composition may contain other components in addition to the resin binder and the boron nitride particles. Other components include, for example, curing agents, curing accelerators, polymerization initiators, and solvents.
　硬化剤としては、制限されず、公知の硬化剤を利用することができる。硬化剤は、ヒドロキシ基、アミノ基、チオール基、イソシアネート基、カルボキシ基、アクリロイル基、メタクリロイル基、及び無水カルボン酸基からなる群より選ばれる少なくとも１種の官能基を有する化合物であることが好ましく、ヒドロキシ基、アクリロイル基、メタクリロイル基、アミノ基、及びチオール基からなる群より選ばれる少なくとも１種の官能基を有する化合物であることがより好ましい。 The curing agent is not limited, and a known curing agent can be used. The curing agent is preferably a compound having at least one functional group selected from the group consisting of a hydroxy group, an amino group, a thiol group, an isocyanate group, a carboxy group, an acryloyl group, a methacryloyl group, and a carboxylic acid anhydride group. A compound having at least one functional group selected from the group consisting of a hydroxy group, an acryloyl group, a methacryloyl group, an amino group, and a thiol group is more preferable.
　硬化剤は、上記官能基を２つ以上有する化合物であることが好ましく、上記官能基を２つ又は３つ有する化合物であることがより好ましい。 The curing agent is preferably a compound having two or more of the above functional groups, and more preferably a compound having two or three of the above functional groups.
　具体的な硬化剤としては、例えば、アミン系硬化剤、フェノール系硬化剤、グアニジン系硬化剤、イミダゾール系硬化剤、ナフトール系硬化剤、アクリル系硬化剤、酸無水物系硬化剤、活性エステル系硬化剤、ベンゾオキサジン系硬化剤、及びシアネートエステル系硬化剤が挙げられる。上記の中でも、硬化剤は、イミダゾール系硬化剤、アクリル系硬化剤、フェノール系硬化剤、又はアミン系硬化剤であることが好ましい。 Specific examples of the curing agent include amine-based curing agents, phenol-based curing agents, guanidine-based curing agents, imidazole-based curing agents, naphthol-based curing agents, acrylic-based curing agents, acid anhydride-based curing agents, and active ester-based curing agents. Examples thereof include a curing agent, a benzoxazine-based curing agent, and a cyanate ester-based curing agent. Among the above, the curing agent is preferably an imidazole-based curing agent, an acrylic-based curing agent, a phenol-based curing agent, or an amine-based curing agent.
　組成物は、１種単独の硬化剤を含んでいてもよく、又は２種以上の硬化剤を含んでいてもよい。 The composition may contain one kind of curing agent alone, or may contain two or more kinds of curing agents.
　組成物が硬化剤を含む場合、硬化剤の含有率は、組成物中の全固形分質量に対して、１～５０質量％であることが好ましく、１質量％～３０質量％であることがより好ましい。 When the composition contains a curing agent, the content of the curing agent is preferably 1 to 50% by mass, preferably 1% by mass to 30% by mass, based on the total solid content mass in the composition. More preferable.
　硬化促進剤としては、制限されず、公知の硬化促進剤を利用することができる。硬化促進剤としては、例えば、トリフェニルホスフィン、２－エチル－４－メチルイミダゾール、三フッ化ホウ素アミン錯体、及び１－ベンジル－２－メチルイミダゾールが挙げられる。 The curing accelerator is not limited, and a known curing accelerator can be used. Examples of the curing accelerator include triphenylphosphine, 2-ethyl-4-methylimidazole, boron trifluoride amine complex, and 1-benzyl-2-methylimidazole.
　組成物は、１種単独の硬化促進剤を含んでいてもよく、又は２種以上の硬化促進剤を含んでいてもよい。 The composition may contain one kind of curing accelerator alone, or may contain two or more kinds of curing accelerators.
　組成物が硬化促進剤を含む場合、硬化促進剤の含有率は、組成物中の全固形分質量に対して、０．１質量％～２０質量％であることが好ましい。 When the composition contains a curing accelerator, the content of the curing accelerator is preferably 0.1% by mass to 20% by mass with respect to the total solid content mass in the composition.
　重合開始剤としては、制限されず、公知の重合開始剤を利用できる。例えば、重合性モノマーが、アクリロイル基、又はメタクリロイル基を有する場合、重合開始剤としては、特開２０１０－１２５７８２号公報の段落００６２に記載された重合開始剤、又は特開２０１５－０５２７１０号公報の段落００５４に記載された重合開始剤であることが好ましい。 The polymerization initiator is not limited, and a known polymerization initiator can be used. For example, when the polymerizable monomer has an acryloyl group or a methacryloyl group, the polymerization initiator is the polymerization initiator described in paragraph 0062 of JP-A-2010-125782, or JP-A-2015-052710. It is preferably the polymerization initiator described in paragraph 0054.
　組成物は、１種単独の重合開始剤を含んでいてもよく、又は２種以上の重合開始剤を含んでいてもよい。 The composition may contain one kind of polymerization initiator alone, or may contain two or more kinds of polymerization initiators.
　組成物が重合開始剤を含む場合、重合開始剤の含有率は、組成物中の全固形分質量に対して、０．１質量％～５０質量％であることが好ましい。 When the composition contains a polymerization initiator, the content of the polymerization initiator is preferably 0.1% by mass to 50% by mass with respect to the total solid content mass in the composition.
　溶媒としては、制限されず、公知の溶媒を利用することができる。溶媒は、有機溶媒であることが好ましい。有機溶媒としては、例えば、酢酸エチル、メチルエチルケトン、ジクロロメタン、及びテトラヒドロフランが挙げられる。 The solvent is not limited, and a known solvent can be used. The solvent is preferably an organic solvent. Examples of the organic solvent include ethyl acetate, methyl ethyl ketone, dichloromethane, and tetrahydrofuran.
　組成物は、１種単独の溶媒を含んでいてもよく、又は２種以上の溶媒を含んでいてもよい。 The composition may contain one kind of solvent alone, or may contain two or more kinds of solvents.
　溶媒の含有率は、制限されず、例えば、組成物の組成、及び塗布方法に応じて決定すればよい。溶媒の含有率は、組成物の全質量に対して、３０質量％～８０質量％であることが好ましく、３０質量％～７０質量％であることがより好ましい。 The content of the solvent is not limited and may be determined according to, for example, the composition of the composition and the coating method. The content of the solvent is preferably 30% by mass to 80% by mass, more preferably 30% by mass to 70% by mass, based on the total mass of the composition.
［基材］
　基材としては、例えば、金属基板、及び剥離ライナーが挙げられる。 [Base material]
Examples of the base material include a metal substrate and a release liner.
　金属基板としては、例えば、鉄基板、銅基板、ステンレス基板、アルミニウム基板、マグネシウム含有合金基板、及びアルミニウム含有合金基板が挙げられる。上記の中でも、金属基板は、銅基板であることが好ましい。 Examples of the metal substrate include an iron substrate, a copper substrate, a stainless steel substrate, an aluminum substrate, a magnesium-containing alloy substrate, and an aluminum-containing alloy substrate. Among the above, the metal substrate is preferably a copper substrate.
　剥離ライナーとしては、例えば、紙（例えば、クラフト紙、グラシン紙、及び上質紙）、樹脂フィルム（例えば、ポリオレフィン、及びポリエステル）、及び紙と樹脂フィルムとを積層したラミネート紙が挙げられる。 Examples of the release liner include paper (for example, kraft paper, glassin paper, and high-quality paper), resin film (for example, polyolefin and polyester), and laminated paper in which paper and resin film are laminated.
　ポリオレフィンとしては、例えば、ポリエチレン、及びポリプロピレンが挙げられる。 Examples of polyolefins include polyethylene and polypropylene.
　ポリエステルとしては、例えば、ポリエチレンテレフタレート（ＰＥＴ）が挙げられる。 Examples of polyester include polyethylene terephthalate (PET).
　剥離ライナーとして使用される紙は、剥離処理が施された紙であってもよい。剥離処理が施された紙は、例えば、目止め処理が施された紙の片面又は両面に剥離処理をさらに施すことによって形成することができる。目止め処理は、例えば、クレイ、又はポリビニルアルコールを用いて行うことができる。剥離処理は、例えば、シリコーン系樹脂を用いて行うことができる。 The paper used as the peeling liner may be paper that has been peeled. The peeling-treated paper can be formed, for example, by further performing a peeling treatment on one side or both sides of the sealing-treated paper. The sealing treatment can be performed using, for example, clay or polyvinyl alcohol. The peeling treatment can be performed using, for example, a silicone-based resin.
　基材の厚さは、制限されず、例えば、１０μｍ～３００μｍの範囲で決定すればよい。 The thickness of the base material is not limited and may be determined in the range of, for example, 10 μm to 300 μm.
［塗布方法］
　塗布方法としては、制限されず、公知の方法を利用できる。塗布方法としては、例えば、ロールコーティング法、グラビア印刷法、スピンコート法、ワイヤーバーコーティング法、押し出しコーティング法、ダイレクトグラビアコーティング法、リバースグラビアコーティング法、ダイコーティング法、スプレー法、コンマコーティング法、ブレード法、及びインクジェット法が挙げられる。 [Applying method]
The coating method is not limited, and a known method can be used. Examples of the coating method include roll coating method, gravure printing method, spin coating method, wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method, spray method, comma coating method, and blade. The method and the inkjet method can be mentioned.
　基材上に塗布された組成物は、必要に応じて乾燥してもよい。乾燥方法としては、例えば、基材上に塗布された組成物に対して、４０℃～１４０℃の温風を１分間～３０分間付与する方法が挙げられる。 The composition applied on the base material may be dried if necessary. Examples of the drying method include a method in which warm air at 40 ° C. to 140 ° C. is applied to the composition coated on the substrate for 1 minute to 30 minutes.
［硬化方法］
　硬化方法としては、制限されず、公知の方法を利用することができる。硬化方法は、熱硬化反応、又は光硬化反応であることが好ましく、熱硬化反応であることが好ましい。 [Curing method]
The curing method is not limited, and a known method can be used. The curing method is preferably a thermosetting reaction or a photocuring reaction, and preferably a thermosetting reaction.
　熱硬化反応における加熱温度は、制限されず、例えば、５０℃～２００℃の範囲で決定すればよい。 The heating temperature in the thermosetting reaction is not limited and may be determined in the range of, for example, 50 ° C. to 200 ° C.
　熱硬化反応における加熱時間は、制限されず、加熱温度に応じて決定すればよい。熱硬化反応における加熱時間は、例えば、１分間～６０分間の範囲で決定すればよい。 The heating time in the thermosetting reaction is not limited and may be determined according to the heating temperature. The heating time in the thermosetting reaction may be determined, for example, in the range of 1 minute to 60 minutes.
　硬化反応は、半硬化反応であってもよい。つまり、得られる硬化物が、いわゆるＢステージ状態（半硬化状態）であってもよい。 The curing reaction may be a semi-curing reaction. That is, the obtained cured product may be in a so-called B stage state (semi-cured state).
　本開示に係る放熱シートの製造方法においては、必要に応じて、硬化反応を複数回にわたって実施してもよい。硬化反応を複数回にわたって実施する場合、各硬化反応の条件は、互いに同一であってもよく、又は異なっていてもよい。 In the method for manufacturing a heat radiating sheet according to the present disclosure, the curing reaction may be carried out a plurality of times, if necessary. When the curing reaction is carried out multiple times, the conditions of each curing reaction may be the same as or different from each other.
［他の工程］
　本開示に係る放熱シートの製造方法は、上記した工程以外の工程（以下、「他の工程」という場合がある。）を含んでいてもよい。他の工程としては、例えば、硬化された組成物（以下、「硬化物」という。）を加圧する工程が挙げられる。 [Other processes]
The method for manufacturing a heat radiating sheet according to the present disclosure may include steps other than the above steps (hereinafter, may be referred to as "other steps"). As another step, for example, a step of pressurizing a cured composition (hereinafter, referred to as “cured product”) can be mentioned.
　硬化物の表面に基材が配置されている場合、硬化物から基材を剥離した後、硬化物を加圧してもよい。また、硬化物から基材を剥離せずに、硬化物を基材と共に加圧してもよい。加工の容易性の観点から、硬化物から基材を剥離した後、硬化物を加圧することが好ましい。 When the base material is arranged on the surface of the cured product, the cured product may be pressurized after the base material is peeled off from the cured product. Further, the cured product may be pressed together with the base material without peeling the base material from the cured product. From the viewpoint of ease of processing, it is preferable to pressurize the cured product after peeling the base material from the cured product.
　加圧方法としては、制限されず、公知の方法を利用することができる。加圧方法としては、例えば、プレス加工、及びカレンダー加工が挙げられる。上記の中でも、加圧方法は、生産性、及び空隙率の減少性の観点から、カレンダー加工であることが好ましい。 The pressurization method is not limited, and a known method can be used. Examples of the pressurizing method include press working and calendering. Among the above, the pressurizing method is preferably calendar processing from the viewpoint of productivity and porosity reduction.
　加圧する際の圧力は、制限されず、例えば、加圧方法、及び硬化物の組成に応じて決定すればよい。例えば、加圧方法がカレンダー加工である場合、圧力（線圧）は、５０Ｎ／ｍ～２００Ｎ／ｍであることが好ましく、１００Ｎ／ｍ～１５０Ｎ／ｍであることがより好ましい。 The pressure at the time of pressurization is not limited and may be determined according to, for example, the pressurization method and the composition of the cured product. For example, when the pressurizing method is calendar processing, the pressure (linear pressure) is preferably 50 N / m to 200 N / m, and more preferably 100 N / m to 150 N / m.
　加圧する際の温度は、制限されず、例えば、加圧方法、硬化物の組成に応じて決定すればよい。温度は、２０℃～１５０℃であることが好ましく、２５℃～１２０℃であることがより好ましい。 The temperature at the time of pressurization is not limited and may be determined according to, for example, the pressurization method and the composition of the cured product. The temperature is preferably 20 ° C. to 150 ° C., more preferably 25 ° C. to 120 ° C.
　加圧方法がカレンダー加工である場合、硬化物の搬送速度は、制限されない。硬化物の搬送速度は、例えば、１ｍ／分～１００ｍ／分の範囲で決定すればよい。 When the pressurizing method is calendar processing, the transport speed of the cured product is not limited. The transport speed of the cured product may be determined, for example, in the range of 1 m / min to 100 m / min.
＜＜用途＞＞
　本開示に係る放熱シートは熱伝導性及び絶縁性に優れるため、本開示に係る放熱シートを種々の発熱体に接触させることで、発熱体において発生した熱を効率的に放熱できる。例えば、電子機器を構成する種々の部品に本開示に係る放熱シートを接触させることで、上記部品において発生した熱を効率的に放熱できる。上記部品としては、例えば、パワーデバイス、及びＣＰＵが挙げられる。また、本開示に係る放熱シートは、パワーデバイス等の発熱体とヒートシンク等の放熱体との間に配置して使用されてもよい。 << Applications >>
Since the heat radiating sheet according to the present disclosure is excellent in thermal conductivity and insulating property, the heat generated in the heating element can be efficiently radiated by bringing the heat radiating sheet according to the present disclosure into contact with various heating elements. For example, by bringing the heat radiating sheet according to the present disclosure into contact with various parts constituting an electronic device, the heat generated in the above parts can be efficiently radiated. Examples of the component include a power device and a CPU. Further, the heat radiating sheet according to the present disclosure may be used by arranging it between a heating element such as a power device and a heat radiating element such as a heat sink.
　以下、実施例により本開示を詳細に説明するが、本開示はこれらに制限されるものではない。なお、特に断りのない限り、「部」、及び「％」は質量基準である。 Hereinafter, the present disclosure will be described in detail by way of examples, but the present disclosure is not limited thereto. Unless otherwise specified, "parts" and "%" are based on mass.
＜実施例１＞
［窒化ホウ素粒子の分級］
　窒化ホウ素粒子（ＨＰ－４０ ＭＦ１００、水島合金鉄株式会社製）を分級（分級機：
日清エンジニアリング株式会社製のエアロファインクラシファイア、分級条件：Ｄ５０＝６μｍ）することによって得られた窒化ホウ素粒子（１）（平板状の１次粒子）、及び窒化ホウ素粒子（ＨＰ－４０ ＭＦ１００、水島合金鉄株式会社製）を分級（分級機：日清エンジニアリング株式会社製のエアロファインクラシファイア、分級条件：Ｄ５０＝７１μｍ）することによって得られた窒化ホウ素粒子（２）（不定形状の２次粒子）を１：１（質量比）で混練することによって、窒化ホウ素粒子（Ａ１）を得た。 <Example 1>
[Classification of boron nitride particles]
Classifying boron nitride particles (HP-40 MF100, manufactured by Mizushima Ferroalloy Co., Ltd.) (classifying machine:
Aerofine classifier manufactured by Nisshin Engineering Co., Ltd., Boron nitride particles (1) (flat plate-shaped primary particles) obtained by classification conditions: D50 = 6 μm), and boron nitride particles (HP-40 MF100, Mizushima) Boron nitride particles (2) (secondary particles of indefinite shape) obtained by classifying (classified by Nisshin Engineering Co., Ltd., aerofine classifier manufactured by Nisshin Engineering Co., Ltd., classification conditions: D50 = 71 μm). Was kneaded at a ratio of 1: 1 (mass ratio) to obtain boron nitride particles (A1).
［組成物（Ａ）の調製］
　下記成分を混練することによって、組成物（Ａ）を調製した。
・モノマー（Ａ）（エポキシ樹脂の原材料、ＱＥ－２４０５、コンビブロックス社製）：１７質量部
・モノマー（Ｂ）（エポキシ樹脂の原材料、ＹＸ４０００、三菱ケミカル株式会社製）：３４質量部
・メチルエチルケトン：６５質量部
・ＴＰＰ（トリフェニルホスフィン、硬化促進剤）：０．５質量部
・窒化ホウ素粒子（Ａ１）：５１質量部 [Preparation of composition (A)]
The composition (A) was prepared by kneading the following components.
・ Monomer (A) (Epoxy resin raw material, QE-2405, manufactured by Combiblocks): 17 parts by mass ・ Monomer (B) (Epoxy resin raw material, YX4000, manufactured by Mitsubishi Chemical Co., Ltd.): 34 parts by mass ・ Methyl ethyl ketone: 65 parts by mass ・ TPP (triphenylphosphine, curing accelerator): 0.5 parts by mass ・ Boron nitride particles (A1): 51 parts by mass
　上記モノマー（Ａ）は、下記構造を有する化合物である。 The above-mentioned monomer (A) is a compound having the following structure.
Figure JPOXMLDOC01-appb-C000001
Figure JPOXMLDOC01-appb-C000001
　上記モノマー（Ｂ）は、下記構造を有する化合物である。 The above-mentioned monomer (B) is a compound having the following structure.
Figure JPOXMLDOC01-appb-C000002
Figure JPOXMLDOC01-appb-C000002
［放熱シートの作製］
　アプリケーターを用いて、ポリエステルフィルム（ＮＰ－１００Ａ、厚さ：１００μｍ、パナック株式会社製）の離型面上に、上記組成物（Ａ）を乾燥後の厚さが２５０μｍになるように塗布し、次いで、１３０℃の温風で５分間乾燥させることによって塗膜を形成した。１８０℃、１時間の条件で上記塗膜を硬化させることにより、ポリエステルフィルム付き放熱シート前駆体を作製した。上記ポリエステルフィルム付き放熱シート前駆体からポリエステルフィルムを剥離した。次に、放熱シート前駆体に対して以下の条件でカレンダー加工を施すことにより、放熱シート（厚さ：２００μｍ）を作製した。カレンダー加工においては、ゴム製のロールと、ＳＵＳ（ステンレス鋼）製のロールと、を有する一対のロールを用いた。放熱シートにおける窒化ホウ素粒子の含有率は、５０質量％である。 [Making a heat dissipation sheet]
Using an applicator, the composition (A) was applied onto the release surface of a polyester film (NP-100A, thickness: 100 μm, manufactured by Panac Co., Ltd.) so that the thickness after drying was 250 μm. Then, a coating film was formed by drying with warm air at 130 ° C. for 5 minutes. A heat-dissipating sheet precursor with a polyester film was prepared by curing the coating film under the conditions of 180 ° C. and 1 hour. The polyester film was peeled off from the precursor of the heat-dissipating sheet with the polyester film. Next, the heat radiating sheet precursor was subjected to calendar processing under the following conditions to prepare a heat radiating sheet (thickness: 200 μm). In the calendering process, a pair of rolls having a rubber roll and a SUS (stainless steel) roll was used. The content of the boron nitride particles in the heat radiating sheet is 50% by mass.
（カレンダー加工の条件）
・線圧：１００Ｎ／ｍ
・温度：２５℃
・搬送速度：５ｍ／分 (Calendar processing conditions)
・ Linear pressure: 100 N / m
・ Temperature: 25 ℃
・ Transport speed: 5m / min
＜実施例２＞
［窒化ホウ素粒子の分級］
　実施例１で用いた窒化ホウ素粒子（１）と窒化ホウ素粒子（２）との混合比（質量比）を１．３：１に変更したこと以外は、実施例１と同様の方法により窒化ホウ素粒子（Ａ２）を得た。 <Example 2>
[Classification of boron nitride particles]
Boron nitride by the same method as in Example 1 except that the mixing ratio (mass ratio) of the boron nitride particles (1) and the boron nitride particles (2) used in Example 1 was changed to 1.3: 1. Particles (A2) were obtained.
［放熱シートの作製］
　組成物（Ａ）における窒化ホウ素粒子（Ａ１）を窒化ホウ素粒子（Ａ２）に変更したこと以外は、実施例１と同様の方法により放熱シートを作製した。 [Making a heat dissipation sheet]
A heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (A2).
＜実施例３＞
［窒化ホウ素粒子の分級］
　実施例１で用いた窒化ホウ素粒子（１）と窒化ホウ素粒子（２）との混合比（質量比）を１．５：１に変更したこと以外は、実施例１と同様の方法により窒化ホウ素粒子（Ａ３）を得た。 <Example 3>
[Classification of boron nitride particles]
Boron nitride by the same method as in Example 1 except that the mixing ratio (mass ratio) of the boron nitride particles (1) and the boron nitride particles (2) used in Example 1 was changed to 1.5: 1. Particles (A3) were obtained.
［放熱シートの作製］
　組成物（Ａ）における窒化ホウ素粒子（Ａ１）を窒化ホウ素粒子（Ａ３）に変更したこと以外は、実施例１と同様の方法により放熱シートを作製した。 [Making a heat dissipation sheet]
A heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (A3).
＜実施例４＞
［窒化ホウ素粒子の分級］
　実施例１で用いた窒化ホウ素粒子（２）を得るための分級条件（Ｄ５０）を８８μｍに変更したこと以外は、実施例１と同様の方法により窒化ホウ素粒子（Ａ４）を得た。 <Example 4>
[Classification of boron nitride particles]
Boron nitride particles (A4) were obtained by the same method as in Example 1 except that the classification condition (D50) for obtaining the boron nitride particles (2) used in Example 1 was changed to 88 μm.
［放熱シートの作製］
　組成物（Ａ）における窒化ホウ素粒子（Ａ１）を窒化ホウ素粒子（Ａ４）に変更したこと以外は、実施例１と同様の方法により放熱シートを作製した。 [Making a heat dissipation sheet]
A heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (A4).
＜実施例５＞
［窒化ホウ素粒子の分級］
　実施例１で用いた窒化ホウ素粒子（２）を得るための分級条件（Ｄ５０）を４２μｍに変更したこと以外は、実施例１と同様の方法により窒化ホウ素粒子（Ａ５）を得た。 <Example 5>
[Classification of boron nitride particles]
Boron nitride particles (A5) were obtained by the same method as in Example 1 except that the classification condition (D50) for obtaining the boron nitride particles (2) used in Example 1 was changed to 42 μm.
［放熱シートの作製］
　組成物（Ａ）における窒化ホウ素粒子（Ａ１）を窒化ホウ素粒子（Ａ５）に変更したこと以外は、実施例１と同様の方法により放熱シートを作製した。 [Making a heat dissipation sheet]
A heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (A5).
＜比較例１＞
［窒化ホウ素粒子の分級］
　実施例１で用いた窒化ホウ素粒子（１）と窒化ホウ素粒子（２）との混合比（質量比）を０．９：１に変更したこと以外は、実施例１と同様の方法により窒化ホウ素粒子（Ｂ１）を得た。 <Comparative example 1>
[Classification of boron nitride particles]
Boron nitride by the same method as in Example 1 except that the mixing ratio (mass ratio) of the boron nitride particles (1) and the boron nitride particles (2) used in Example 1 was changed to 0.9: 1. Particles (B1) were obtained.
［放熱シートの作製］
　組成物（Ａ）における窒化ホウ素粒子（Ａ１）を窒化ホウ素粒子（Ｂ１）に変更したこと以外は、実施例１と同様の方法により放熱シートを作製した。 [Making a heat dissipation sheet]
A heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (B1).
＜比較例２＞
［窒化ホウ素粒子の分級］
　実施例１で用いた窒化ホウ素粒子（１）と窒化ホウ素粒子（２）との混合比（質量比）を１．６：１に変更したこと以外は、実施例１と同様の方法により窒化ホウ素粒子（Ｂ２）を得た。 <Comparative example 2>
[Classification of boron nitride particles]
Boron nitride by the same method as in Example 1 except that the mixing ratio (mass ratio) of the boron nitride particles (1) and the boron nitride particles (2) used in Example 1 was changed to 1.6: 1. Particles (B2) were obtained.
［放熱シートの作製］
　組成物（Ａ）における窒化ホウ素粒子（Ａ１）を窒化ホウ素粒子（Ｂ２）に変更したこと以外は、実施例１と同様の方法により放熱シートを作製した。 [Making a heat dissipation sheet]
A heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (B2).
＜比較例３＞
［窒化ホウ素粒子の分級］
　実施例１で用いた窒化ホウ素粒子（２）を得るための分級条件（Ｄ５０）を８８μｍに変更したこと、及び実施例１で用いた窒化ホウ素粒子（１）と窒化ホウ素粒子（２）との混合比（質量比）を１：０．９に変更したこと以外は、実施例１と同様の方法により窒化ホウ素粒子（Ｂ３）を得た。 <Comparative example 3>
[Classification of boron nitride particles]
The classification condition (D50) for obtaining the boron nitride particles (2) used in Example 1 was changed to 88 μm, and the boron nitride particles (1) and boron nitride particles (2) used in Example 1 were used. Boron nitride particles (B3) were obtained by the same method as in Example 1 except that the mixing ratio (mass ratio) was changed to 1: 0.9.
［放熱シートの作製］
　組成物（Ａ）における窒化ホウ素粒子（Ａ１）を窒化ホウ素粒子（Ｂ３）に変更したこと以外は、実施例１と同様の方法により放熱シートを作製した。 [Making a heat dissipation sheet]
A heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (B3).
＜比較例４＞
［窒化ホウ素粒子の分級］
　実施例１で用いた窒化ホウ素粒子（２）を得るための分級条件（Ｄ５０）を４２μｍに変更したこと、及び実施例１で用いた窒化ホウ素粒子（１）と窒化ホウ素粒子（２）との混合比（質量比）を１：１．１に変更したこと以外は、実施例１と同様の方法により窒化ホウ素粒子（Ｂ４）を得た。 <Comparative example 4>
[Classification of boron nitride particles]
The classification condition (D50) for obtaining the boron nitride particles (2) used in Example 1 was changed to 42 μm, and the boron nitride particles (1) and boron nitride particles (2) used in Example 1 were used. Boron nitride particles (B4) were obtained by the same method as in Example 1 except that the mixing ratio (mass ratio) was changed to 1: 1.1.
［放熱シートの作製］
　組成物（Ａ）における窒化ホウ素粒子（Ａ１）を窒化ホウ素粒子（Ｂ４）に変更したこと以外は、実施例１と同様の方法により放熱シートを作製した。 [Making a heat dissipation sheet]
A heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (B4).
＜比較例５＞
［窒化ホウ素粒子の分級］
　実施例１で用いた窒化ホウ素粒子（１）を、窒化ホウ素粒子（Ｂ５）として用いた。 <Comparative example 5>
[Classification of boron nitride particles]
The boron nitride particles (1) used in Example 1 were used as the boron nitride particles (B5).
［放熱シートの作製］
　組成物（Ａ）における窒化ホウ素粒子（Ａ１）を窒化ホウ素粒子（Ｂ５）に変更したこと以外は、実施例１と同様の方法により放熱シートを作製した。 [Making a heat dissipation sheet]
A heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (B5).
＜比較例６＞
［窒化ホウ素粒子の分級］
　実施例１で用いた窒化ホウ素粒子（２）を、窒化ホウ素粒子（Ｂ６）として用いた。 <Comparative Example 6>
[Classification of boron nitride particles]
The boron nitride particles (2) used in Example 1 were used as the boron nitride particles (B6).
［放熱シートの作製］
　組成物（Ａ）における窒化ホウ素粒子（Ａ１）を窒化ホウ素粒子（Ｂ６）に変更したこと以外は、実施例１と同様の方法により放熱シートを作製した。 [Making a heat dissipation sheet]
A heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (B6).
＜比較例７＞
［窒化ホウ素粒子の準備］
　窒化ホウ素粒子（Ｂ７）として、窒化ホウ素粒子（ＭＯＭＥＮＴＩＶＥ社製、窒化ホウ素（ＢＮ）パウダー　ＰＴＸ２５）を準備した。窒化ホウ素粒子（Ｂ７）は、球状の１次粒子であった。 <Comparative Example 7>
[Preparation of boron nitride particles]
Boron nitride particles (Boron Nitride (BN) powder PTX25, manufactured by MOMENTIVE) were prepared as boron nitride particles (B7). The boron nitride particles (B7) were spherical primary particles.
［放熱シートの作製］
　組成物（Ａ）における窒化ホウ素粒子（Ａ１）を窒化ホウ素粒子（Ｂ７）に変更したこと以外は、実施例１と同様の方法により放熱シートを作製した。 [Making a heat dissipation sheet]
A heat radiating sheet was produced by the same method as in Example 1 except that the boron nitride particles (A1) in the composition (A) were changed to the boron nitride particles (B7).
＜空隙率＞
　実施例及び比較例で作製した放熱シートの空隙率を以下の方法によって測定した。測定結果を表１に示す。
　（１）３次元Ｘ線顕微鏡（株式会社リガク製の「ｎａｎｏ３ＤＸ」）を用いて、放熱シートの観察像（視野範囲：２００μｍ×２００μｍ）を得た。
　（２）任意の５つの観察像（視野範囲：２００μｍ×２００μｍ）を二値化処理し、各観察像から空隙率（［空隙の面積］／［視野範囲の面積］）を算出した。
　（３）５つの測定値を算術平均することによって、放熱シートの空隙率（％）を算出した。 <Porosity>
The porosity of the heat radiating sheets produced in Examples and Comparative Examples was measured by the following method. The measurement results are shown in Table 1.
(1) An observation image (visual field range: 200 μm × 200 μm) of the heat radiating sheet was obtained using a three-dimensional X-ray microscope (“nano3DX” manufactured by Rigaku Co., Ltd.).
(2) Arbitrary five observation images (visual field range: 200 μm × 200 μm) were binarized, and the porosity ([area of void] / [area of visual field range]) was calculated from each observation image.
(3) The porosity (%) of the heat radiating sheet was calculated by arithmetically averaging the five measured values.
＜耐電圧＞
　実施例及び比較例で作製した放熱シート（シート単体）の耐電圧を以下の方法によって測定した。「ＪＩＳ　Ｃ　２１１０－１：２０１６」に準ずる方法によって実施した絶縁破壊試験において、試験片が絶縁破壊を起こさない最も高い電圧を耐電圧とした。測定結果を表１に示す。耐電圧の数値が高いほど、絶縁性が高いことを意味する。 <Withstand voltage>
The withstand voltage of the heat radiating sheet (sheet alone) produced in Examples and Comparative Examples was measured by the following method. In the dielectric breakdown test carried out by a method according to "JIS C 2110-1: 2016", the highest voltage at which the test piece does not cause dielectric breakdown was defined as the withstand voltage. The measurement results are shown in Table 1. The higher the withstand voltage value, the higher the insulation.
＜熱伝導率＞
　実施例及び比較例で作製した放熱シート（シート単体）の熱伝導率を以下の方法によって測定した。測定結果を表１に示す。熱伝導率が高いほど、熱伝導性が高いことを意味する。
　（１）ＮＥＴＺＳＣＨ社製の「ＬＦＡ４６７」を用いて、レーザーフラッシュ法で放熱シートの厚み方向の熱拡散率を測定した。
　（２）メトラー・トレド株式会社製の天秤「ＸＳ２０４」（「固体比重測定キット」使用）を用いて、放熱シートの比重を測定した。
　（３）セイコーインスツル株式会社製の「ＤＳＣ３２０／６２００」を用い、１０℃／分の昇温条件の下、２５℃における各放熱シートの比熱をＤＳＣ７のソフトウエアを用いて比熱を求めた。
　（４）得られた熱拡散率に比重及び比熱を乗じることで、放熱シートの熱伝導率を算出した。 <Thermal conductivity>
The thermal conductivity of the heat radiating sheet (sheet alone) produced in Examples and Comparative Examples was measured by the following method. The measurement results are shown in Table 1. The higher the thermal conductivity, the higher the thermal conductivity.
(1) Using "LFA467" manufactured by NETZSCH, the thermal diffusivity in the thickness direction of the heat dissipation sheet was measured by a laser flash method.
(2) The specific gravity of the heat radiating sheet was measured using the balance "XS204" (using the "solid specific gravity measurement kit") manufactured by METTLER TOLEDO Co., Ltd.
(3) Using "DSC320 / 6200" manufactured by Seiko Instruments Inc., the specific heat of each heat dissipation sheet at 25 ° C. was determined using the software of DSC7 under the heating condition of 10 ° C./min.
(4) The thermal conductivity of the heat radiating sheet was calculated by multiplying the obtained thermal diffusivity by the specific gravity and the specific heat.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　表１に記載したＢＮ粒子（Ａ）、ＢＮ粒子（Ｂ）、ＢＮ粒子（Ｃ）、及びＢＮ粒子（Ｄ）の各含有率は、放熱シートに含まれる窒化ホウ素粒子の全個数に対する割合である。 The content of each of the BN particles (A), BN particles (B), BN particles (C), and BN particles (D) shown in Table 1 is a ratio to the total number of boron nitride particles contained in the heat dissipation sheet. ..
　表１より、実施例１～５は、比較例１～７に比べて、熱伝導性、及び絶縁性に優れることがわかった。 From Table 1, it was found that Examples 1 to 5 were superior in thermal conductivity and insulating property as compared with Comparative Examples 1 to 7.
　２０１９年９月２５日に出願された日本国特許出願２０１９－１７３８３３号の開示は、その全体が参照により本明細書に取り込まれる。本明細書に記載された全ての文献、特許出願、及び技術規格は、個々の文献、特許出願、及び技術規格が参照により取り込まれることが具体的かつ個々に記載された場合と同程度に、本明細書に参照により取り込まれる。 The disclosure of Japanese Patent Application No. 2019-173833, filed on September 25, 2019, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are to the same extent as if the individual documents, patent applications, and technical standards were specifically and individually stated to be incorporated by reference. Incorporated herein by reference.

Claims (7)

  1. 　樹脂バインダーと、窒化ホウ素粒子と、を含み、
    　前記窒化ホウ素粒子のうち、粒径が１μｍ～１０μｍである窒化ホウ素粒子の含有率が、前記窒化ホウ素粒子の全個数に対して、４０％～６０％であり、
    　前記窒化ホウ素粒子のうち、粒径が２０μｍ～７０μｍであり、かつ、アスペクト比が１．３以上である窒化ホウ素粒子の含有率が、前記窒化ホウ素粒子の全個数に対して、２０％～３０％である
    　放熱シート。     Containing a resin binder and boron nitride particles,
    Among the boron nitride particles, the content of the boron nitride particles having a particle size of 1 μm to 10 μm is 40% to 60% with respect to the total number of the boron nitride particles.
    Among the boron nitride particles, the content of the boron nitride particles having a particle size of 20 μm to 70 μm and an aspect ratio of 1.3 or more is 20% to 30% of the total number of the boron nitride particles. Heat dissipation sheet that is%.
  2. 　前記窒化ホウ素粒子のうち、粒径が１０μｍを超え２０μｍ未満である窒化ホウ素粒子の含有率が、前記窒化ホウ素粒子の全個数に対して、５％～１０％である請求項１に記載の放熱シート。 The heat dissipation according to claim 1, wherein the content of the boron nitride particles having a particle size of more than 10 μm and less than 20 μm among the boron nitride particles is 5% to 10% with respect to the total number of the boron nitride particles. Sheet.
  3. 　前記窒化ホウ素粒子のうち、粒径が７０μｍを超える窒化ホウ素粒子の含有率が、前記窒化ホウ素粒子の全個数に対して、１０％～３０％である請求項１に記載の放熱シート。 The heat radiating sheet according to claim 1, wherein the content of the boron nitride particles having a particle size of more than 70 μm among the boron nitride particles is 10% to 30% with respect to the total number of the boron nitride particles.
  4. 　前記窒化ホウ素粒子のうち、粒径が１０μｍを超え２０μｍ未満である窒化ホウ素粒子の含有率が、前記窒化ホウ素粒子の全個数に対して、５％以上１０％未満であり、かつ、粒径が７０μｍを超える窒化ホウ素粒子の含有率が、前記窒化ホウ素粒子の全個数に対して、０％を超え３０％以下である請求項１に記載の放熱シート。 Among the boron nitride particles, the content of the boron nitride particles having a particle size of more than 10 μm and less than 20 μm is 5% or more and less than 10% with respect to the total number of the boron nitride particles, and the particle size is The heat-dissipating sheet according to claim 1, wherein the content of the boron nitride particles exceeding 70 μm is more than 0% and 30% or less with respect to the total number of the boron nitride particles.
  5. 　空隙率が、０％～３％である請求項１～請求項４のいずれか１項に記載の放熱シート。 The heat radiating sheet according to any one of claims 1 to 4, wherein the porosity is 0% to 3%.
  6. 　前記粒径が２０μｍ～７０μｍであり、かつ、アスペクト比が１．３以上である窒化ホウ素粒子の個数に対する、前記粒径が１μｍ～１０μｍである窒化ホウ素粒子の個数の比が、１．５～２．０である請求項１～請求項５のいずれか１項に記載の放熱シート。 The ratio of the number of boron nitride particles having a particle size of 1 μm to 10 μm to the number of boron nitride particles having a particle size of 20 μm to 70 μm and an aspect ratio of 1.3 or more is 1.5 to 1. The heat radiating sheet according to any one of claims 1 to 5, which is 2.0.
  7. 　前記窒化ホウ素粒子の含有率が、前記放熱シートの全質量に対して、４５質量％～８０質量％である請求項１～請求項６のいずれか１項に記載の放熱シート。 The heat radiating sheet according to any one of claims 1 to 6, wherein the content of the boron nitride particles is 45% by mass to 80% by mass with respect to the total mass of the heat radiating sheet.
PCT/JP2020/025718 2019-09-25 2020-06-30 Heat dissipation sheet WO2021059647A1 (en)

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