WO2021085383A1 - 熱伝導性シート及びその製造方法 - Google Patents
熱伝導性シート及びその製造方法 Download PDFInfo
- Publication number
- WO2021085383A1 WO2021085383A1 PCT/JP2020/040121 JP2020040121W WO2021085383A1 WO 2021085383 A1 WO2021085383 A1 WO 2021085383A1 JP 2020040121 W JP2020040121 W JP 2020040121W WO 2021085383 A1 WO2021085383 A1 WO 2021085383A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- filler
- conductive sheet
- scaly
- heat conductive
- axis direction
- Prior art date
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 17
- 239000000945 filler Substances 0.000 claims abstract description 273
- 239000011159 matrix material Substances 0.000 claims abstract description 45
- 229920000642 polymer Polymers 0.000 claims abstract description 44
- 239000012765 fibrous filler Substances 0.000 claims description 84
- 239000000203 mixture Substances 0.000 claims description 79
- 238000000034 method Methods 0.000 claims description 22
- 239000002245 particle Substances 0.000 claims description 20
- 229920005989 resin Polymers 0.000 claims description 17
- 239000011347 resin Substances 0.000 claims description 17
- 238000010030 laminating Methods 0.000 claims description 16
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 14
- 238000005520 cutting process Methods 0.000 claims description 14
- 239000000843 powder Substances 0.000 claims description 9
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 8
- 239000004917 carbon fiber Substances 0.000 claims description 8
- 239000002243 precursor Substances 0.000 claims description 8
- 229910052582 BN Inorganic materials 0.000 claims description 6
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 claims description 6
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical group C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 6
- 239000007788 liquid Substances 0.000 description 54
- 238000011049 filling Methods 0.000 description 35
- 239000000835 fiber Substances 0.000 description 33
- 229920001296 polysiloxane Polymers 0.000 description 22
- 229920002050 silicone resin Polymers 0.000 description 22
- 239000011231 conductive filler Substances 0.000 description 19
- 238000010438 heat treatment Methods 0.000 description 19
- 238000001723 curing Methods 0.000 description 16
- 230000001965 increasing effect Effects 0.000 description 16
- 238000002360 preparation method Methods 0.000 description 15
- 239000003795 chemical substances by application Substances 0.000 description 13
- 230000006835 compression Effects 0.000 description 11
- 238000007906 compression Methods 0.000 description 11
- 238000012546 transfer Methods 0.000 description 11
- 239000011357 graphitized carbon fiber Substances 0.000 description 10
- 229910052751 metal Inorganic materials 0.000 description 10
- 239000002184 metal Substances 0.000 description 10
- 238000010008 shearing Methods 0.000 description 8
- 238000005087 graphitization Methods 0.000 description 7
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 7
- 239000011248 coating agent Substances 0.000 description 6
- 238000000576 coating method Methods 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 6
- 230000017525 heat dissipation Effects 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 239000011302 mesophase pitch Substances 0.000 description 6
- -1 polydimethylsiloxane Polymers 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 239000000654 additive Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 150000004767 nitrides Chemical class 0.000 description 5
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 5
- 230000000996 additive effect Effects 0.000 description 4
- 239000000853 adhesive Substances 0.000 description 4
- 230000001070 adhesive effect Effects 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 4
- 125000003342 alkenyl group Chemical group 0.000 description 3
- 239000003575 carbonaceous material Substances 0.000 description 3
- 239000003054 catalyst Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 229920001577 copolymer Polymers 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 150000001247 metal acetylides Chemical class 0.000 description 3
- 229910000000 metal hydroxide Inorganic materials 0.000 description 3
- 150000004692 metal hydroxides Chemical class 0.000 description 3
- 229910044991 metal oxide Inorganic materials 0.000 description 3
- 150000004706 metal oxides Chemical class 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 229920005992 thermoplastic resin Polymers 0.000 description 3
- UFWIBTONFRDIAS-UHFFFAOYSA-N Naphthalene Chemical compound C1=CC=CC2=CC=CC=C21 UFWIBTONFRDIAS-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 229910018557 Si O Inorganic materials 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- 238000007259 addition reaction Methods 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 2
- 239000003963 antioxidant agent Substances 0.000 description 2
- 230000003078 antioxidant effect Effects 0.000 description 2
- 230000033228 biological regulation Effects 0.000 description 2
- 238000003763 carbonization Methods 0.000 description 2
- 238000013329 compounding Methods 0.000 description 2
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 229920001971 elastomer Polymers 0.000 description 2
- 230000002708 enhancing effect Effects 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 230000001771 impaired effect Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 229920006136 organohydrogenpolysiloxane Polymers 0.000 description 2
- 239000011295 pitch Substances 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 229920002239 polyacrylonitrile Polymers 0.000 description 2
- 229920000139 polyethylene terephthalate Polymers 0.000 description 2
- 239000005020 polyethylene terephthalate Substances 0.000 description 2
- 238000010298 pulverizing process Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 2
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Inorganic materials [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 238000009987 spinning Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229920001187 thermosetting polymer Polymers 0.000 description 2
- 238000002834 transmittance Methods 0.000 description 2
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 239000004820 Pressure-sensitive adhesive Substances 0.000 description 1
- 229910008051 Si-OH Inorganic materials 0.000 description 1
- 229910006358 Si—OH Inorganic materials 0.000 description 1
- 229920006311 Urethane elastomer Polymers 0.000 description 1
- 208000012886 Vertigo Diseases 0.000 description 1
- 229920000800 acrylic rubber Polymers 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 125000002091 cationic group Chemical group 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 239000007822 coupling agent Substances 0.000 description 1
- 229910021419 crystalline silicon Inorganic materials 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000004205 dimethyl polysiloxane Substances 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000003063 flame retardant Substances 0.000 description 1
- 150000002391 heterocyclic compounds Chemical class 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000012948 isocyanate Substances 0.000 description 1
- 150000002513 isocyanates Chemical class 0.000 description 1
- 238000004898 kneading Methods 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- NJPPVKZQTLUDBO-UHFFFAOYSA-N novaluron Chemical compound C1=C(Cl)C(OC(F)(F)C(OC(F)(F)F)F)=CC=C1NC(=O)NC(=O)C1=C(F)C=CC=C1F NJPPVKZQTLUDBO-UHFFFAOYSA-N 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 229920000435 poly(dimethylsiloxane) Polymers 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 238000006068 polycondensation reaction Methods 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 229920005862 polyol Polymers 0.000 description 1
- 150000003077 polyols Chemical class 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 238000007348 radical reaction Methods 0.000 description 1
- 238000007363 ring formation reaction Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 238000003892 spreading Methods 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
Images
Classifications
-
- 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
- H01L23/373—Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon
- H01L23/3737—Organic materials with or without a thermoconductive filler
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/18—Manufacture of films or sheets
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B38/00—Ancillary operations in connection with laminating processes
- B32B38/0004—Cutting, tearing or severing, e.g. bursting; Cutter details
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
- B29C70/58—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising fillers only, e.g. particles, powder, beads, flakes, spheres
- B29C70/62—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising fillers only, e.g. particles, powder, beads, flakes, spheres the filler being oriented during moulding
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
- B29C70/88—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts characterised primarily by possessing specific properties, e.g. electrically conductive or locally reinforced
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
- B32B27/20—Layered products comprising a layer of synthetic resin characterised by the use of special additives using fillers, pigments, thixotroping agents
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
- H01L21/48—Manufacture or treatment of parts, e.g. containers, prior to assembly of the devices, using processes not provided for in a single one of the subgroups H01L21/06 - H01L21/326
- H01L21/4814—Conductive parts
- H01L21/4871—Bases, plates or heatsinks
- H01L21/4882—Assembly of heatsink parts
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B38/00—Ancillary operations in connection with laminating processes
- B32B2038/0052—Other operations not otherwise provided for
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2250/00—Layers arrangement
- B32B2250/24—All layers being polymeric
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2250/00—Layers arrangement
- B32B2250/44—Number of layers variable across the laminate
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
- B32B2262/10—Inorganic fibres
- B32B2262/106—Carbon fibres, e.g. graphite fibres
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2264/00—Composition or properties of particles which form a particulate layer or are present as additives
- B32B2264/10—Inorganic particles
- B32B2264/102—Oxide or hydroxide
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2264/00—Composition or properties of particles which form a particulate layer or are present as additives
- B32B2264/10—Inorganic particles
- B32B2264/107—Ceramic
- B32B2264/108—Carbon, e.g. graphite particles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2264/00—Composition or properties of particles which form a particulate layer or are present as additives
- B32B2264/30—Particles characterised by physical dimension
- B32B2264/303—Average diameter greater than 1µm
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2264/00—Composition or properties of particles which form a particulate layer or are present as additives
- B32B2264/30—Particles characterised by physical dimension
- B32B2264/308—Aspect ratio of particles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2305/00—Condition, form or state of the layers or laminate
- B32B2305/30—Fillers, e.g. particles, powders, beads, flakes, spheres, chips
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/30—Properties of the layers or laminate having particular thermal properties
- B32B2307/302—Conductive
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/70—Other properties
- B32B2307/732—Dimensional properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2313/00—Elements other than metals
- B32B2313/02—Boron
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2383/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen, or carbon only; Derivatives of such polymers
- C08J2383/04—Polysiloxanes
- C08J2383/07—Polysiloxanes containing silicon bound to unsaturated aliphatic groups
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2483/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen, or carbon only; Derivatives of such polymers
- C08J2483/04—Polysiloxanes
- C08J2483/05—Polysiloxanes containing silicon bound to hydrogen
-
- 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
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/20—Oxides; Hydroxides
- C08K3/22—Oxides; Hydroxides of metals
- C08K2003/2227—Oxides; Hydroxides of metals of aluminium
-
- 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
- C08K2003/382—Boron-containing compounds and nitrogen
- C08K2003/385—Binary compounds of nitrogen with boron
-
- 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
- C08K3/02—Elements
- C08K3/04—Carbon
-
- 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
-
- 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
- C08K7/06—Elements
-
- 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
- C08K7/16—Solid spheres
- C08K7/18—Solid spheres inorganic
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
- C08L83/04—Polysiloxanes
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
- C09K5/08—Materials not undergoing a change of physical state when used
- C09K5/14—Solid materials, e.g. powdery or granular
Definitions
- the present invention relates to a thermally conductive sheet and a method for producing the same.
- a heat sink such as a heat sink is generally used to dissipate heat generated from a heating element such as a semiconductor element or a mechanical part.
- a heat conductive sheet is arranged between a heating element and a heat radiating element for the purpose of increasing the heat transfer efficiency to the heat radiating element.
- the heat conductive sheet generally contains a polymer matrix and a heat conductive filler dispersed in the polymer matrix. Further, in the heat conductive sheet, in order to enhance the heat conductivity in a specific direction, an anisotropic filler having anisotropy in shape may be oriented in one direction.
- the thermally conductive sheet in which the anisotropic filler is oriented in one direction includes, for example, a plurality of primary sheets in which the anisotropic filler such as a fibrous filler is oriented along the sheet surface direction by stretching or the like. It is manufactured by vertically slicing a product obtained by laminating a plurality of primary sheets and integrating them. According to this manufacturing method (hereinafter, also referred to as “fluid orientation method”), a thermally conductive sheet formed by laminating a large number of unit layers having a small thickness can be obtained. Further, the anisotropic filler can be oriented in the thickness direction of the sheet, and the thermal conductivity in the thickness direction becomes good (see, for example, Patent Document 1). Since the heat conductive sheet has high heat conductivity in the thickness direction, it is possible to efficiently dissipate the heat generated by the heating element to the outside inside the electronic device.
- a heat spot where the temperature rises locally may occur inside an electronic device.
- a heat diffusion sheet having excellent thermal conductivity in the surface direction may be used.
- the heat resistance of an electronic element generally differs depending on the type of the electronic element, for example, when an element having a low heat resistance exists on a substrate, it is necessary to prevent heat transfer in that direction. In that case, it is required to increase the thermal conductivity in a specific direction in the plane, while decreasing the thermal conductivity in a direction other than that direction.
- the conventional heat diffusion sheet is inferior in thermal conductivity in the thickness direction, it is inferior in the efficiency of transferring the heat generated by the heating element to the radiator, and it diffuses the heat isotropically, so that the heat is diffused in a specific direction. It is difficult to suppress the heat conduction of.
- the heat conductive sheet obtained by the conventional flow orientation method or the like in which the anisotropic filler is oriented in the thickness direction of the sheet is excellent in the efficiency of transferring the heat generated by the heating element to the heating element, but the sheet. It is difficult to increase the thermal conductivity in the direction along the surface direction of.
- an object of the present invention is to provide a thermally conductive sheet having high thermal conductivity not only in the thickness direction of the sheet but also in one direction along the surface direction of the sheet.
- the present invention provides the following [1] to [12].
- [1] A thermally conductive sheet containing a scaly filler in a polymer matrix.
- the scaly filler is provided along one of a first direction in which the major axis direction of the scaly surface is the thickness direction of the heat conductive sheet and a second direction in which the scaly filler is perpendicular to the first direction.
- a heat conductive sheet in which the horizontal axis direction perpendicular to the long axis direction on the scale surface is oriented along the other of the first direction and the second direction.
- the scaly filler contains scaly boron nitride powder.
- the heat conductive sheet according to any one of the above [1] to [10] which further contains a non-anisotropic filler in the polymer matrix.
- thermoly conductive sheet having high thermal conductivity not only in the thickness direction of the sheet but also in one direction along the surface direction of the sheet.
- FIG. 1 is a schematic view of the heat conductive sheet 10 of the first embodiment
- FIG. 2 is a schematic view for explaining the details of the scaly filler 12.
- the thermally conductive sheet 10 according to the first embodiment includes a polymer matrix 11 and a scaly filler 12 dispersed in the polymer matrix 11.
- the length direction on the scaly surface is the major axis direction Y
- the direction perpendicular to the major axis direction on the scaly surface is the horizontal axis direction X
- these major axis directions Y is shown in the scaly filler 12
- the length direction on the scaly surface is the major axis direction Y
- the direction perpendicular to the major axis direction on the scaly surface is the horizontal axis direction X
- these major axis directions Y is shown in the scaly filler 12
- the length direction on the scaly surface is the major axis direction Y
- the scaly filler 12 is a thermally conductive filler that enhances the thermal conductivity of the thermally conductive sheet 10.
- the scaly filler 12 has a major axis direction Y along the first direction which is the thickness direction of the heat conductive sheet 10 and a horizontal axis direction X in the first direction. Oriented along a second direction that is vertical.
- the second direction is one direction in the surface direction of the sheet. Therefore, the heat conductive sheet 10 has good heat conductivity in one direction in the surface direction of the heat conductive sheet 10 in addition to the thickness direction.
- the direction perpendicular to both the first and second directions is defined as the third direction.
- the third direction is one direction along the surface direction of the heat conductive sheet 10.
- the heat conductive sheet 10 has good heat conductivity in one direction in the surface direction in addition to the thickness direction, so that heat dissipation effect is enhanced and heat is released in the surface direction to prevent heat spots from being generated. To do. Further, since the thermal conductivity is not so increased in the direction other than one direction in the plane direction, for example, when an element having low heat resistance is present on the substrate, it is possible to prevent heat transfer in that direction. It will be possible.
- the thermally conductive sheet 10 may contain an anisotropic filler other than the scaly filler 12 in addition to the scaly filler 12 as the thermally conductive filler dispersed in the polymer matrix 11. Specifically, as shown in FIG. 1, it is preferable to contain the fibrous filler 13.
- the heat conductive sheet contains the fibrous filler 13 in addition to the scaly filler 12, so that the fibrous filler 13 exists between the scaly filler 12 and the scaly filler 12, for example. As a result, a heat conduction path is well formed and high heat conductivity can be obtained.
- the fibrous filler 13 is oriented so that its fiber axis direction is along the first direction, which is the thickness direction of the sheet.
- the thermal conductivity sheet 10 can further increase the thermal conductivity in the thickness direction (first direction) of the sheet, and can further increase the thermal conductivity in the first direction. It becomes easy to make the thermal conductivity along the second direction sufficiently higher than the thermal conductivity along the second direction.
- the thermally conductive sheet 10 contains a non-anisotropic filler (not shown) as the thermally conductive filler dispersed in the polymer matrix 11. Since the thermally conductive sheet 10 contains a non-anisotropic filler, a filler having thermal conductivity between the anisotropic filler such as the scaly filler 12 and the anisotropic filler can be appropriately used. Intervening, the thermal conductivity becomes even better.
- the anisotropic filler is a filler having anisotropy in shape and capable of orientation. Anisotropic fillers typically have any aspect ratio greater than 2.
- the non-anisotropic filler is a filler having substantially no anisotropy in shape, and even in an environment in which the anisotropic filler is oriented in a predetermined direction, such as under the action of shearing force described later. , A filler that does not orient in its predetermined direction. As will be described later, the non-anisotropic filler has, for example, an aspect ratio of 2 or less.
- the scaly filler 12 may be used alone or both the scaly filler 12 and the fibrous filler 13 may be used as the thermally conductive filler contained in the polymer matrix 11.
- the scaly filler 12 and the non-anisotropic filler may be used in combination.
- the scaly filler 12, the fibrous filler 13 and the non-anisotropic filler may be used in combination.
- the polymer matrix 11 is a member that holds a thermally conductive filler such as a scaly filler 12, and is preferably made of a flexible rubber-like elastic body.
- the polymer matrix is formed from a resin that is a precursor thereof.
- the precursor referred to in the present specification is a concept that includes not only a substance that becomes a polymer matrix 11 by reacting as described later, but also a substance that does not react and is the same as the polymer matrix 11.
- the resin is required to have fluidity during the alignment step.
- the resin that is the precursor of the polymer matrix 11 is a thermoplastic resin
- the anisotropic filler can be oriented in a state of being heated and plasticized.
- a reactive liquid resin if the anisotropic filler is oriented before curing and the resin is cured while maintaining the state, a cured product in which the anisotropic filler is oriented can be obtained.
- the thermoplastic resin has a relatively high viscosity, and if it is plasticized to a low viscosity, the resin may be thermally deteriorated. Therefore, it is preferable to use a reactive liquid resin.
- the reactive liquid resin it is preferable to use rubber or gel which is liquid before the reaction and is cured under predetermined conditions to form a crosslinked structure.
- the crosslinked structure means that at least a part of the polymer is three-dimensionally crosslinked to form a cured product which is not melted by heating.
- the viscosity is preferably low, and after orientation, the mixture is cured under predetermined conditions. Those having possible properties are preferable.
- thermosetting and photocurable ones examples include thermosetting and photocurable ones.
- a thermosetting rubber or the like can be used. It is preferable to use a gel. More specifically, silicone resin, urethane rubber utilizing the reaction of polyol and isocyanate, acrylic rubber utilizing the radical reaction or cationic reaction of acrylate, and the like can be exemplified, but it is preferable to use a silicone resin.
- the silicone resin is not particularly limited as long as it is an organopolysiloxane, but it is preferable to use a curable silicone resin.
- the silicone resin is obtained by curing the curable silicone composition.
- an addition reaction type silicone resin may be used, or other silicone resins may be used.
- the curable silicone composition preferably comprises a silicone compound as a main agent and a curing agent that cures the main agent.
- the silicone compound used as the main agent is preferably an alkenyl group-containing organopolysiloxane, and specifically, a vinyl group-containing polydimethylsiloxane, a vinyl group-containing polyphenylmethylsiloxane, a vinyl group-containing dimethylsiloxane-diphenylsiloxane copolymer, and a vinyl group.
- examples thereof include vinyl group-containing organopolysiloxanes such as a vinyl group-containing dimethylsiloxane-phenylmethylsiloxane copolymer and a vinyl group-containing dimethylsiloxane-diethylsiloxane copolymer.
- the curing agent is not particularly limited as long as it can cure the silicone compound as the main agent, but organohydrogenpolysiloxane, which is an organopolysiloxane having two or more hydrosilyl groups (SiH), is preferable.
- organohydrogenpolysiloxane which is an organopolysiloxane having two or more hydrosilyl groups (SiH)
- the hardness of the primary sheet which will be described later, can be adjusted by appropriately adjusting the number of hydrosilyl groups, the molecular weight, and the compounding amount ratio with respect to the main agent of the curing agent. Specifically, the hardness of the primary sheet can be lowered by using a curing agent having a small number of hydrosilyl groups in one molecule or having a large molecular weight, or by reducing the mixing amount ratio of the curing agent to the main agent.
- the content of the polymer matrix in the heat conductive sheet is preferably 15 to 50% by volume, more preferably 20 to 45% by volume, based on the total amount of the heat conductive sheet in terms of volume% (filling rate). ..
- the scaly filler 12 has a first aspect ratio represented by the ratio of the length in the major axis direction Y to the length in the horizontal axis direction X (length in the major axis direction Y / length in the horizontal axis direction X).
- the ratio is preferably 1.5 or more.
- the thermal conductivity in the first direction is significantly higher than the thermal conductivity in the second direction (one direction in the plane direction).
- heat conductivity in the thickness direction is enhanced while preventing heat transfer more than necessary in the surface direction, and it becomes easy to enhance the heat dissipation effect.
- the first aspect ratio is more preferably 1.7 or more.
- the first aspect ratio may be 1 or more, and if the first aspect ratio is, for example, less than 1.5, there is a significant difference in thermal conductivity between the first direction and the second direction.
- the first aspect ratio is, for example, 5 or less, preferably 3 or less, and more preferably 2.5 or less in order to impart a certain level of thermal conductivity or more in the second direction.
- the scaly filler 12 has a ratio (length) of the length in the major axis direction Y to the length in the thickness direction Z from the viewpoint of facilitating orientation in the first direction (thickness direction) and enhancing thermal conductivity.
- the second aspect ratio represented by (the length in the axial direction Y / the length in the thickness direction Z) is preferably 3 or more, and more preferably 6 to 300. Further, in order to reduce the viscosity of the mixture containing each material, the second aspect ratio is more preferably 8 to 15, while the scaly filler 12 is prevented from falling off from the cured product and has thermal conductivity. It is more preferable that the second aspect ratio is 15 to 300 from the viewpoint of increasing the above aspect ratio. The second aspect ratio is usually larger than the first aspect ratio.
- the average particle size of the scaly filler 12 is preferably 20 ⁇ m or more.
- the average particle size is the average of the lengths in the major axis direction Y.
- the average particle size is 20 ⁇ m or more, it becomes easy to align the scaly filler 12 along the first direction (thickness direction), and it becomes easy to bring the fillers into contact with each other, so that a heat transfer path is secured.
- the average particle size of the scaly filler 12 is more preferably 30 ⁇ m or more, further preferably 40 ⁇ m or more, still more preferably 60 ⁇ m or more.
- the average particle size of the scaly filler 12 is preferably 400 ⁇ m or less, more preferably 300 ⁇ m or less, and more preferably 200 ⁇ m or less. Is even more preferable, and 150 ⁇ m or less is even more preferable.
- the scaly filler 12 may be used alone or in combination of two or more. For example, as the scaly filler 12, at least two materials having different average particle diameters may be used.
- the aspect ratio (first and second aspect ratios) and the average particle size of the scaly filler 12 can be determined by observing with a microscope and measuring each length. For example, with respect to the scaly filler 12 separated by melting the matrix component of the heat conductive sheet 10, the length of any 50 scaly filler 12 in the major axis direction is measured using an electron microscope or an optical microscope. Then, the average value (arithmetic mean value) can be used as the average particle size. At this time, a large share is not applied so as not to crush the scaly filler 12.
- the length Y of the scaly filler 12 in the major axis direction is measured using an X-ray CT device, and the average thereof is measured.
- the value (arithmetic mean value) can also be used as the average particle size.
- the length in the major axis direction Y, the length in the horizontal axis direction X, and the length in the thickness direction Z (that is, the thickness) of any 50 scaly fillers 12 are measured and averaged.
- the first and second aspect ratios may be obtained from the ratio of the values (arithmetic mean value).
- an arbitrary thing means a thing randomly selected.
- the scaly filler 12 examples include scaly carbon powder, scaly silicon carbide powder, scaly aluminum nitride powder, scaly boron nitride powder, and scaly aluminum oxide powder. Among them, at least one selected from scaly graphite powder and scaly boron nitride powder is preferable from the viewpoint of thermal conductivity. Further, the scaly filler 12 is more preferably scaly graphite powder from the viewpoint of improving the thermal conductivity, particularly the thermal conductivity in the first direction.
- the scaly graphite powder has graphite crystal planes connected in the in-plane direction of the scaly plane, and has high thermal conductivity in the in-plane direction. Therefore, by aligning the scale surfaces in a predetermined direction, the thermal conductivity in a specific direction can be increased.
- the scaly graphite powder preferably has a high degree of graphitization.
- the content of the scaly filler 12 in the heat conductive sheet 10 is preferably 8 to 400 parts by mass with respect to 100 parts by mass of the polymer matrix.
- the content of the scaly filler 12 in the heat conductive sheet 10 is more preferably 40 to 300 parts by mass, and further preferably 70 to 200 parts by mass.
- the content of the scaly filler 12 is preferably 5 to 50% by volume, more preferably 8 to 40 volumes, based on the volume-based filling rate (volume filling rate) with respect to the total amount of the heat conductive sheet. %, More preferably 13 to 30% by volume.
- the heat conductive sheet 10 may be used in combination with another anisotropic filler such as the fibrous filler 13, but when the scaly filler 12 is used in combination with the fibrous filler 13.
- the preferable value of the total amount of the scaly filler 12 and the fibrous filler 13 is as described later.
- the scaly filler 12 has a major axis direction Y along the first direction of the heat conductive sheet 10 and a horizontal axis direction X along the second direction of the heat conductive sheet 10.
- the fact that the major axis direction Y is along the first direction means that the angle (orientation angle) formed by the major axis direction Y with respect to the first direction of the heat conductive sheet 10 is less than 30 °. It means that the ratio of the number of 12 is in a state of exceeding 50% with respect to the total amount of the scaly filler, and the ratio is preferably more than 80%.
- the ratio of the number of scaly fillers 12 formed by the horizontal axis direction X to the second direction of the heat conductive sheet 10 is less than 30 °. However, it means that it is in a state of exceeding 50% with respect to the total amount of the scaly filler, and the ratio preferably exceeds 80%.
- the angle (orientation angle) formed by the major axis direction Y with respect to the first direction of the scaly filler 12 is preferably 0 ° or more and less than 30 °.
- the angle is an average value of the orientation angles of a fixed number of scaly fillers 12 (for example, 50 arbitrary scaly fillers 12). Further, from the viewpoint of increasing the thermal conductivity in the second direction, the angle formed by the horizontal axis direction X with respect to the second direction of the scaly filler 12 is preferably 0 ° or more and less than 30 °, and the angle is preferably 0 ° or more and less than 30 °. , An average value of the angles formed by a certain number of scaly fillers 12 (for example, 50 arbitrary scaly fillers 12).
- the heat conductive sheet 10 preferably contains the fibrous filler 13 dispersed in the polymer matrix 11.
- the fibrous filler 13 preferably has an aspect ratio of 4 or more, and more preferably 7 to 100, from the viewpoint of facilitating the orientation of the fiber axial direction in the first direction and enhancing the thermal conductivity. It is preferably 15 to 50, and more preferably 15 to 50.
- the aspect ratio means the length (fiber length) of the fibrous filler 13 in the fiber axis direction / the diameter of the fiber.
- the first aspect ratio of the scaly filler 12 and the aspect ratio of the fibrous filler 13 are, in other words, the first direction with respect to the length of the anisotropic filler in the second direction. It can be said that it is the ratio of the lengths of the anisotropic fillers in. Therefore, the weighted average value (also referred to as "first direction / second direction aspect ratio") of the first aspect ratio of the scaly filler 12 and the aspect ratio of the fibrous filler 13 is anisotropic. It can also be said to be a ratio indicating how much the filler is oriented in the first direction with respect to the second direction.
- the weighted average value of the aspect ratio is the compounding amount (the first aspect ratio for the scaly filler 12 and the aspect ratio for the fibrous filler 13) of each anisotropic filler. It is a value averaged by weighting the volume ratio).
- the aspect ratio in the first direction / second direction may be 1 or more, preferably 1.5 or more, more preferably 1.7 or more, and even more preferably 3 or more. When this aspect ratio is 1.5 or more, the thermal conductivity in the thickness direction becomes high in the present embodiment, and the heat dissipation effect when used in an electronic device or the like becomes high.
- the aspect ratio in the first direction / second direction is, for example, preferably 8 or less, more preferably 7 or less, and even more preferably 5 or less. When this aspect ratio is 8 or less, the thermal conductivity in the plane direction becomes high in the present embodiment, and it becomes easy to prevent heat spots and the like.
- the average fiber length of the fibrous filler 13 is preferably 20 to 500 ⁇ m, more preferably 80 to 400 ⁇ m.
- the fillers are appropriately contacted with each other in the heat conductive sheet, a heat transfer path is secured, and the heat conductivity of the heat conductive sheet 10 is improved.
- the average fiber length is 500 ⁇ m or less, the bulk of the fibrous filler 13 becomes low and high filling becomes possible. Further, even if a conductive filler 13 is used, it is possible to prevent the heat conductive sheet 10 from becoming unnecessarily high in conductivity.
- the average fiber length can be calculated by observing the fibrous filler 13 with a microscope.
- the fibrous lengths of any 50 fibrous fillers 13 are measured using an electron microscope or an optical microscope, and the fiber lengths thereof are measured.
- the average value (arithmetic mean value) can be used as the average fiber length. At this time, do not take a large share so as not to crush the fiber.
- the fiber length of the fibrous filler 13 is measured using an X-ray CT device, and the average fiber length is calculated. May be good.
- the diameter of the fibrous filler 13 can also be measured by using an electron microscope, an optical microscope, and an X-ray CT apparatus in the same manner.
- the fibrous filler 13 examples include carbon fiber, metal fiber, ceramic fiber, polyparaphenylene benzoxazole fiber and the like. Of these, carbon fiber is preferable. As the carbon fiber, graphitized carbon fiber is preferable. The graphitized carbon fibers have graphite crystal planes connected in the fiber axis direction, and have high thermal conductivity in the fiber axis direction. Therefore, by aligning the fiber axis directions in a predetermined direction, the thermal conductivity in a specific direction can be increased. The graphitized carbon fiber preferably has a high degree of graphitization.
- a graphitized material of the following raw materials can be used.
- examples thereof include condensed polycyclic hydrocarbon compounds such as naphthalene, condensed heterocyclic compounds such as PAN (polyacrylonitrile) and pitch, and graphitized mesophase pitch, polyimide and polybenzazole having a particularly high degree of graphitization should be used. Is preferable.
- the mesophase pitch in the spinning process described later, the pitch is oriented in the fiber axis direction due to its anisotropy, and graphitized carbon fibers having excellent thermal conductivity in the fiber axis direction can be obtained.
- the mode of use of the mesophase pitch in the graphitized carbon fiber is not particularly limited as long as it can be spun, and the mesophase pitch may be used alone or in combination with other raw materials.
- the use of the mesophase pitch alone that is, the graphitized carbon fiber having a mesophase pitch content of 100% is most preferable from the viewpoint of high thermal conductivity, spinnability and quality stability.
- the graphitized carbon fiber one obtained by sequentially performing each treatment of spinning, insolubilization and carbonization and then pulverized or cut to a predetermined particle size and then graphitized, or one which is pulverized or cut after carbonization and then graphitized may be used. it can.
- the polycondensation reaction and cyclization reaction easily proceed during the graphitization treatment on the surface newly exposed by pulverization, so that the degree of graphitization is increased and heat conduction is further increased.
- Graphitized carbon fibers with improved properties can be obtained.
- the carbon fibers after graphitization are rigid and easily pulverized, and carbon fiber powder having a relatively narrow fiber length distribution can be obtained by pulverization in a short time.
- the fibrous filler 13 may be used alone or in combination of two or more.
- at least two fillers having different average fiber lengths may be used as the fibrous filler 13.
- the fibrous filler 13 is oriented so that its fiber axial direction is along the first direction.
- the ratio of the number of fibrous fillers 13 having an angle formed by the major axis of the fibrous filler 13 less than 30 ° with respect to the first direction is defined as It means that it is in a state of exceeding 50% with respect to the total amount of the fibrous filler, and the ratio preferably exceeds 80%.
- the orientation direction of the fibrous filler 13 is such that the angle (orientation angle) formed by the fiber axis direction of the fibrous filler 13 with respect to the first direction is 0 ° or more and less than 5 ° from the viewpoint of increasing the thermal conductivity. It is preferable that the angle is an average value of the orientation angles of a fixed number (for example, 50 arbitrary fibrous fillers 13) of the fibrous fillers 13.
- the mass ratio of the scaly filler 12 and the fibrous filler 13 is preferably from 20/80 to 20/80. It is 95/5, more preferably 30/70 to 90/10, and even more preferably 55/45 to 80/20.
- the mass ratio is preferably from 20/80 or more.
- the amount of the scaly filler 12 can be made constant or more, so that it becomes easy to improve the thermal conductivity not only in the first direction but also in the second direction. ..
- the content is 95/5 or less, the effect of containing the fibrous filler 13 can be easily exerted, and for example, the thermal conductivity in the first direction can be easily improved.
- the total content of the scaly filler 12 and the fibrous filler 13 in the heat conductive sheet 10 is preferably 10 to 500 parts by mass with respect to 100 parts by mass of the polymer matrix. When the total content is 10 parts by mass or more, the thermal conductivity is easily increased, and when the total content is 500 parts by mass or less, the viscosity of the liquid composition described later is likely to be appropriate, and the orientation of each filler is improved. It will be good. From these viewpoints, the total content of the scaly filler 12 and the fibrous filler 13 in the heat conductive sheet 10 is more preferably 50 to 350 parts by mass, and more preferably 80 to 250 parts by mass. More preferred. The total content is preferably 2 to 50% by volume, more preferably 8 to 40% by volume, based on the volume-based filling rate (volume filling rate), based on the total amount of the heat conductive sheet. , More preferably 15 to 30% by volume.
- the scaly filler 12 and the fibrous filler 13 are not particularly limited, but generally have a thermal conductivity of 30 W / (m ⁇ ) along the direction having anisotropy (that is, the major axis direction and the fiber axis direction). K) or more, preferably 100 W / (m ⁇ K) or more.
- the upper limit of the thermal conductivity is not particularly limited, but is, for example, 2000 W / (m ⁇ K) or less.
- the method for measuring thermal conductivity is a laser flash method. Further, the scaly filler 12 and the fibrous filler 13 may have conductivity or insulation.
- having conductivity means, for example, a case where the volume resistivity is 1 ⁇ 10 9 ⁇ ⁇ cm or less. Further, as having insulating property shall refer to for example, when the volume resistivity is more than 1 ⁇ 10 9 ⁇ ⁇ cm.
- the thermally conductive sheet 10 preferably contains a non-anisotropic filler (not shown) in the polymer matrix 11.
- the non-anisotropic filler is a material that imparts thermal conductivity to the thermally conductive sheet 10 together with an anisotropic filler such as the scaly filler 12.
- the filler is interposed between the anisotropic fillers such as the oriented scaly filler 12, and a thermally conductive sheet having a higher thermal conductivity can be obtained. ..
- the non-anisotropic filler is a filler having substantially no anisotropy in shape, and the anisotropic filler such as the scaly filler 12 is oriented in a predetermined direction under the action of shearing force described later. It is a filler that does not orient in a predetermined direction even in an environment where it is used.
- the non-anisotropic filler has an aspect ratio of less than 2, more preferably 1.5 or less. By setting the aspect ratio to less than 2, it is possible to prevent the viscosity of the liquid composition described later from increasing and to achieve high filling.
- the non-anisotropic filler may have conductivity, but is preferably insulating, and in the heat conductive sheet 10, the filler (that is, the scaly filler 12 or the scales) to be blended is used. It is preferable that the shape filler 12, the fibrous filler 13, and the non-anisotropic filler) have insulating properties. When these are insulating, it becomes easy to improve the insulating property in the thickness direction of the heat conductive sheet 10 in the present embodiment.
- non-anisometric filler examples include metals, metal oxides, metal nitrides, metal hydroxides, carbon materials, oxides other than metals, nitrides, carbides and the like.
- the shape of the non-anisotropic filler includes spherical and amorphous powders.
- examples of the metal include aluminum, copper and nickel
- examples of the metal oxide include aluminum oxide typified by alumina, magnesium oxide and zinc oxide
- examples of the metal nitride examples include aluminum nitride. can do.
- the metal hydroxide examples include aluminum hydroxide.
- examples of the carbon material include spheroidal graphite.
- oxides, nitrides and carbides other than metals include quartz, boron nitride and silicon carbide.
- examples of the non-anisometric filler having insulating properties include metal oxides, metal nitrides, metal hydroxides, and metal carbides.
- aluminum oxide and aluminum are preferable because they have high thermal conductivity and spherical ones are easily available, and aluminum hydroxide is easily available and the heat conductive sheet is difficult. It is preferable because it can increase the flammability. Of these, aluminum oxide is more preferred.
- the average particle size of the non-anisotropic filler is preferably 0.1 to 50 ⁇ m, more preferably 0.5 to 35 ⁇ m. Further, it is particularly preferably 1 to 20 ⁇ m. By setting the average particle size to 50 ⁇ m or less, problems such as disturbing the orientation of the anisotropic filler such as the scaly filler are less likely to occur. Further, by setting the average particle size to 0.1 ⁇ m or more, the specific surface area of the non-anisotropic filler does not become larger than necessary, and the viscosity of the liquid composition does not easily increase even if a large amount is blended. It becomes easier to highly fill the anisotropic filler.
- the average particle size of the non-anisotropic filler can be measured by observing with an electron microscope or the like. More specifically, as in the measurement with the scaly filler 12 and the fibrous filler 13, the particle size of 50 arbitrary non-anisometric fillers can be determined by using an electron microscope, an optical microscope, and an X-ray CT device. It can be measured and the average value (arithmetic mean value) can be used as the average particle size.
- the non-anisotropic filler may be used alone or in combination of two or more.
- the average particle size of each filler is a value calculated without distinguishing between two or more types of each filler.
- the content of the non-anisotropic filler in the thermally conductive sheet 10 is preferably in the range of 50 to 1500 parts by mass, and preferably in the range of 200 to 800 parts by mass with respect to 100 parts by mass of the polymer matrix. Is more preferable, and more preferably in the range of 250 to 550 parts by mass.
- the amount is 50 parts by mass or more, the amount of the non-anisotropic filler interposed in the gap of the anisotropic filler such as the scaly filler 12 becomes a certain amount or more, and the thermal conductivity is improved.
- the content when the content is 1500 parts by mass or less, the effect of increasing the thermal conductivity according to the content can be obtained, and the anisotropic filler such as the scaly filler 12 is used as the non-anisotropic filler. It does not interfere with heat conduction. Further, when the content is in the range of 200 to 800 parts by mass, the thermal conductivity of the thermally conductive sheet 10 is excellent, and the viscosity of the liquid composition is also suitable.
- the content of the non-anisotropic filler is preferably 10 to 75% by volume, more preferably 30 to 60% by volume, and 35 to 50% by volume with respect to the total amount of the heat conductive sheet in terms of volume%. Is even more preferable.
- additives may be further added to the polymer matrix 11 as long as the function as the heat conductive sheet 10 is not impaired.
- the additive include at least one selected from a dispersant, a coupling agent, a pressure-sensitive adhesive, a flame retardant, an antioxidant, a colorant, an antioxidant and the like.
- a curing catalyst or the like that accelerates the curing may be blended as an additive.
- the curing catalyst include platinum-based catalysts.
- the heat conductive sheet 10 is not particularly limited, but is made of a plurality of unit layers 14 by being manufactured by the manufacturing method described later.
- Each unit layer 14 in the heat conductive sheet 10 contains a scaly filler 12. As shown in FIG. 1, the plurality of unit layers 14 are laminated along a third direction, and adjacent unit layers 14 are adhered to each other.
- Each unit layer 14 may contain the scaly filler 12 alone, the scaly filler 12 and the fibrous filler 13 as the heat conductive filler, or the scales.
- the shape filler 12 and the non-anisotropic filler 12 (not shown in FIG. 1) may be contained.
- the scaly filler 12, the fibrous filler 13, and the non-anisotropic filler may be contained.
- each unit layer 14 has substantially the same composition. Therefore, the contents of the scaly filler 12, the fibrous filler 13, the non-anisotropic filler, and the polymer matrix in each unit layer 14 are the same as the contents in the heat conductive sheet, and each unit layer.
- the contents and filling rate of the scaly filler 12, the fibrous filler 13, the non-anisotropic filler, and the polymer matrix 11 in No. 14 are also as described above.
- the scaly filler 12 is oriented so that the major axis direction Y is along the first direction and the horizontal axis direction X is along the second direction as described above.
- the fibrous filler 13 is oriented in each unit layer 14 so that the fiber axial direction is along the first direction.
- the polymer matrix 11 becomes a component that retains the above-mentioned heat conductive filler, and in each unit layer 14, each of the above-mentioned heat conductive fillers is dispersed in the polymer matrix 11. Formulated as follows.
- the thermal conductivity of the heat conductive sheet 10 in the first direction is, for example, 5 W / (m ⁇ K) or more, preferably 8 W / (m ⁇ K) or more, and 11 W / (m ⁇ K) or more. Is more preferable. By setting these lower limits or more, the thermal conductivity of the heat conductive sheet 10 in the thickness direction can be made excellent. Although there is no particular upper limit, the thermal conductivity of the heat conductive sheet 10 in the thickness direction is, for example, 50 W / (m ⁇ K) or less. The thermal conductivity shall be measured by a method based on ASTM D5470-06.
- the scaly filler 12 is oriented so that its horizontal axis direction X is along the second direction. Therefore, high thermal conductivity is also shown in the second direction.
- the thermal conductivity of the heat conductive sheet 10 in the second direction is preferably 2.5 W / (m ⁇ K) or more, more preferably 3 W / (m ⁇ K) or more, and 4.5 W. It is more preferable that it is / (m ⁇ K) or more. Further, there is no upper limit to the thermal conductivity of the heat conductive sheet 10 in the second direction, but it is, for example, 50 W / (m ⁇ K) or less.
- the scaly filler 12 is oriented as described above, so that the heat conductivity in the third direction (the direction perpendicular to the second direction along the plane direction) is the first. It is lower than the thermal conductivity in the direction and the second direction.
- the thermal conductivity of the heat conductive sheet 10 in the third direction is preferably less than 4.5 W / (m ⁇ K), more preferably less than 3 W / (m ⁇ K), and more preferably 2.5 W. It is more preferably less than / (m ⁇ K).
- the lower limit of the thermal conductivity of the heat conductive sheet 10 in the third direction is not particularly limited, but is, for example, 0.2 W / (m ⁇ K) or more.
- the thermal characteristic level in the second direction obtained by the following formula is preferably 10% or more.
- the heat conductive sheet 10 has anisotropy of heat conductivity in the surface direction, transfers heat in one direction in the surface direction, and prevents heat transfer in the other direction. it can.
- the thermal characteristic level in the second direction is more preferably 20% or more, further preferably 50% or more.
- the thermal characteristic level in the second direction may be 100% or less, but from the viewpoint of increasing the thermal conductivity in the thickness direction to be higher than the thermal conductivity in the plane direction to improve heat dissipation. , 90% or less is preferable, and 80% or less is more preferable.
- Thermal characteristic level (%) in the second direction ( ⁇ 2- ⁇ 3) / ( ⁇ 1- ⁇ 3) ⁇ 100 ⁇ 1: Thermal conductivity in the first direction ⁇ 2: Thermal conductivity in the second direction ⁇ 3: Thermal conductivity in the third direction
- the type E hardness of the thermally conductive sheet 10 is, for example, 70 or less.
- the heat conductive sheet 10 has a type E hardness of 70 or less, so that flexibility is ensured. For example, the followability to a heating element and a heat radiator is good, and the heat dissipation is likely to be good. Further, when it is used for an adherend having large irregularities, it is preferable that it is extremely flexible, and the type OO hardness of the heat conductive sheet 10 is preferably 62 or less. Since the type OO hardness of the heat conductive sheet 10 is 62 or less, the heat conductive sheet becomes extremely flexible, and the followability to the heating element and the heat radiating body becomes extremely good.
- the type OO hardness of the heat conductive sheet 10 is preferably 50 or less, more preferably 45 or less.
- the type OO hardness of the heat conductive sheet 10 is not particularly limited, but is, for example, 15 or more, preferably 18 or more, and more preferably 25 or more.
- the type E hardness of the heat conductive sheet 10 is preferably 15 or more, and particularly preferably 35 or more. The softer the hardness of the thermal conductive sheet 10 is, the smaller the stress on the heating element, the heat radiating element, the substrate on which they are placed, etc. when compressed, which is preferable.
- the heat conductive sheet 10 can be made easier to be attached to the adherend by improving the predetermined handleability.
- the type E hardness is 35 or more, the balance between handleability and softness can be excellent.
- the type E hardness and the type OO hardness are values measured using a predetermined durometer according to the method specified in ASTM D2240-05.
- the type OO hardness of the heat conductive sheet 10 and the primary sheet described later was measured according to the regulations of ASTM D2240-05.
- the type OO hardness is adjusted so that the test piece has a hardness of 10 mm, and the hardness of both sides of the test piece is measured to calculate the average value.
- the thickness is less than 10 mm, a plurality of sheets are stacked and adjusted so that the thickness of the test piece is 10 mm, or is larger than 10 mm and closest to 10 mm.
- the scaly filler 12 or the anisotropic filler such as the scaly filler 12 and the fibrous filler 13 is exposed on either of the surfaces 10A and 10B of the heat conductive sheet 10. Further, the exposed scaly filler 12, or the scaly filler 12 and the fibrous filler 13 may protrude from both surfaces 10A and 10B, respectively. In the heat conductive sheet 10, the anisotropic filler is exposed on the surfaces 10A and 10B, so that the surfaces 10A and 10B become non-adhesive surfaces.
- Both surfaces 10A and 10B of the heat conductive sheet 10 become cut surfaces by, for example, cutting with a cutting tool described later, and thereby, the scale-like filler 12 or the scale-like filling on both surfaces 10A and 10B, respectively.
- the material 12 and the fibrous filler 13 are exposed.
- either one or both of the surfaces 10A and 10B may be adhesive surfaces without exposing the anisotropic filler.
- the thickness of the heat conductive sheet 10 is appropriately changed according to the shape and application of the electronic device on which the heat conductive sheet 10 is mounted.
- the thickness of the heat conductive sheet 10 is not particularly limited, but may be used in the range of, for example, 0.1 to 5 mm.
- each unit layer 14 is not particularly limited, but is preferably 0.1 to 10.0 mm.
- the major axis direction Y and the horizontal axis direction X of the scaly filler 12 can be set along the first and second directions, respectively, due to the flow orientation described later. It becomes possible to align them. Further, when the fibrous filler 13 is used, it becomes easy to align the long axis direction of the fibrous filler 13 along the first direction. From these viewpoints, the thickness of each unit layer 14 is more preferably 0.3 to 5.0 mm, further preferably 0.5 to 3 mm.
- the thickness of the unit layer 14 is 14 L in length along the third direction.
- the compression ratio is at least these lower limit values, the flexibility becomes high, and it becomes easy to compress and use it inside an electronic device or the like.
- each unit layer 14 does not spread due to the pressure when the unit layers 14 are laminated at the time of manufacturing the heat conductive sheet 10, and it becomes easy to appropriately manufacture the heat conductive sheet 10.
- the compression ratio is more preferably 25% or more.
- the compression ratio is preferably 60% or less, more preferably 55% or less.
- the heat conductive sheet 10 can be adjusted within the predetermined range described above by adhering the primary sheets to each other by VUV irradiation to prevent the compression rate from increasing.
- the compressibility in the present invention is measured when a plurality of unit layers 14 are compressed from a direction perpendicular to the adhesive surface to which they adhere to each other.
- the first thermal conductive sheet 10 is measured. It is preferable to compress in the direction of (thickness direction).
- the compression ratio indicates the ratio of the amount of compression to the initial thickness indicated by "(T1-T2) / T1", where T1 is the initial thickness before compression and T2 is the thickness when compressed at a predetermined pressure. It is a parameter.
- the compressibility may be measured, for example, by cutting a thermally conductive sheet into a size of 10 mm ⁇ 10 mm and sandwiching a test piece between a pedestal having a flat surface and a presser that presses in parallel.
- the heat conductive sheet 10 is used inside an electronic device or the like. Specifically, the heat conductive sheet 10 is interposed between the heating element and the heat radiating element, conducts heat generated by the heating element, transfers the heat to the radiating element, and dissipates heat from the radiating element.
- the heating element include various electronic components such as a CPU, a power amplifier, and a power supply used inside an electronic device.
- the radiator include a heat sink, a heat pump, and a metal housing of an electronic device.
- the heat conductive sheet 10 is used, for example, with both surfaces 10A and 10B in close contact with each of the heating element and the heat radiating element and compressed.
- the heat conductive sheet 10 in the present embodiment has high heat conductivity in the first direction (thickness direction), so that it has excellent heat dissipation, and has a constant heat conductivity in the surface direction. It becomes easier to prevent heat spots and the like from occurring. Furthermore, since thermal conductivity cannot be enhanced in any direction other than one direction in the plane direction, for example, if an element having low heat resistance is present inside an electronic device, it is possible to prevent heat transfer in that direction. It will be possible.
- a mixture preparation step of preparing a mixture containing a resin which is a precursor of a polymer matrix and at least a scaly filler 12 as a thermally conductive filler, and a flow orientation treatment of the above-mentioned mixture are performed.
- each step will be described in detail.
- a resin for example, in the case of a silicone resin, a curable silicone composition
- a mixture liquid composition containing the scaly filler 12
- the fibrous filler 13 and the non-anisotropic filler may be further added to the mixture as appropriate, and additional components may be further added to the mixture.
- the liquid composition is usually a slurry.
- a known kneader, kneading roll, mixer or the like may be used.
- the viscosity of the liquid composition is preferably 100 to 10000 Pa ⁇ s.
- a shearing force is applied in the alignment treatment step to form a sheet while flowing the filler, so that the major axis direction Y of the scaly filler 12 is in the flow direction (in the sheet surface direction).
- the value is 10,000 Pa ⁇ s or less, the coatability is improved.
- the viscosity of the liquid composition is more preferably 300 to 3000 Pa ⁇ s, and even more preferably 400 to 2000 Pa ⁇ s.
- the viscosity is the viscosity measured at a rotation speed of 1 rpm using a rotational viscometer (Brookfield viscometer DV-E, spindle SC4-14), and the measured temperature is the temperature at the time of coating the liquid composition. Is.
- the viscosity of the liquid composition can be adjusted by the type and amount of the above-mentioned heat conductive filler. Further, it can be appropriately adjusted depending on each component constituting the resin. For example, when the liquid composition is a curable silicone composition, the molecular weight of each component (alkenyl group-containing organopolysiloxane, organohydrogenpolysiloxane, etc.) constituting the curable silicone composition should be appropriately adjusted. Then, the above viscosity may be used. Further, the liquid composition may contain an organic solvent as needed to adjust the viscosity, but it is preferable that the liquid composition does not contain an organic solvent.
- the liquid composition is formed into a sheet while applying a shearing force to obtain a primary sheet.
- the liquid composition may be applied onto the base film by, for example, an applicator for coating such as a bar coater or a doctor blade, extrusion molding, ejection from a nozzle, or the like. By such a method, the liquid composition may be applied.
- a shearing force can be applied along the coating direction (flow direction).
- the scaly filler 12 By forming the scaly filler 12 into a sheet while applying a shearing force in this way, the scaly filler 12 has a major axis direction Y along the flow direction (one direction in the sheet surface direction) and a horizontal axis direction X in the flow direction. Oriented along a direction perpendicular to (the other direction in the sheet plane direction).
- the fibrous filler 13 is oriented so that the fiber axis direction thereof follows the flow direction.
- the liquid composition formed into a sheet is cured, dried, etc., if necessary, to obtain a primary sheet.
- the major axis direction Y of the scaly filler 12 is oriented in one direction in the plane direction
- the horizontal axis direction X is oriented in the other direction in the plane direction.
- the liquid composition contains, for example, a curable silicone composition
- the liquid composition is cured by curing the curable silicone composition.
- the liquid composition may be cured by heating, but for example, it may be performed at a temperature of about 50 to 150 ° C.
- the heating time is, for example, about 10 minutes to 3 hours.
- the solvent may be volatilized by heating during curing.
- the thickness of the primary sheet obtained by curing is preferably in the range of 0.1 to 10 mm.
- the anisotropic filler particularly the scaly filler 12
- the thickness of the primary sheet is more preferably 0.3 to 5.0 mm, still more preferably 0.5 to 3.0 mm.
- the type OO hardness of the primary sheet is preferably 6 or more. When the number is 6 or more, the primary sheet does not spread so much even if pressure is applied when laminating the primary sheets, and a laminated block having a sufficient thickness can be produced. From such a viewpoint, the type OO hardness of the primary sheet is more preferably 10 or more, and further preferably 15 or more. Further, from the viewpoint of ensuring the flexibility of the obtained heat conductive sheet 10, the type OO hardness of the primary sheet is preferably 55 or less, more preferably 50 or less, still more preferably 40 or less. Further, from the viewpoint of improving the handleability of the obtained heat conductive sheet 10, the type E hardness of the primary sheet is preferably 70 or less, more preferably 40 or less. The type E hardness of the primary sheet is preferably 10 or more, more preferably 30 or more.
- the plurality of primary sheets 17 obtained in the primary sheet preparation step are laminated so that the orientation directions of the anisotropic fillers are the same (see FIGS. 3A and 3B). That is, one direction along the major axis direction Y and each other direction along the horizontal axis direction X of the scaly filler 12 are laminated so as to coincide with each other among the plurality of primary sheets 17. Then, the plurality of laminated primary sheets 17 are adhered to each other and integrated to obtain a laminated block 18.
- the resin of the laminated primary sheets 17 is a thermoplastic resin
- the polymer matrix 11 in the primary sheets 17 may be melt-fixed to form a laminated block 18 by press molding.
- a known adhesive or the like may be arranged between the primary sheets 17 and 17 to bond the primary sheets 17 and 17.
- a known adhesive or the like may be arranged between the primary sheets 17 and 17 to bond the primary sheets 17 and 17.
- a known adhesive or the like may be arranged between the primary sheets 17 and 17 to bond the primary sheets 17 and 17.
- the polymer matrix is a silicone resin or the like
- at least one surface of the obtained primary sheet 17 is irradiated with VUV to activate at least one surface, and by that surface, 1
- the next sheets 17 and 17 may be adhered to each other.
- the VUV is a vacuum ultraviolet ray, and means an ultraviolet ray having a wavelength of 10 to 200 nm.
- Examples of the VUV light source include an excimer Xe lamp and an excimer ArF lamp.
- the primary sheet 17 contains, for example, a silicone resin (organopolysiloxane) as described above
- a silicone resin organopolysiloxane
- the primary sheet 17 is overlapped with the other primary sheet 17 so that one of the activated surfaces becomes a superposed surface, so that the space between the primary sheets 17 and 17 is firmly formed. It will be glued.
- the silicone resin when VUV is irradiated, the C—Si bond of the organopolysiloxane changes to the Si—O bond such as Si—OH, and the Si—O bond causes the silicone resin. It is presumed that the primary sheets 17 and 17 are firmly adhered to each other.
- the primary sheet 17 and the primary sheet (unit layers 14, 14) are adhered by forming a bond between the molecules of the organopolysiloxane. Further, by adhering the primary sheets 17 and 17 to each other by VUV irradiation, the flexibility in the direction perpendicular to the laminating direction is not significantly impaired. Therefore, it becomes easy to adjust the above-mentioned compression ratio within a predetermined range.
- the VUV irradiation conditions are not particularly limited as long as the surface of the primary sheet 17 can be activated, but for example, the integrated light amount is 5 to 100 mJ / cm 2 , preferably the integrated light amount is 10 to 50 mJ / cm 2. Irradiation with VUV is recommended.
- each of the primary sheets 17 may be subjected to VUV irradiation in advance on any one of the overlapping surfaces that are in contact with each other. Since one surface is irradiated with VUV, the adjacent primary sheets 17 and 17 are adhered to each other by the activated one surface. Further, from the viewpoint of further improving the adhesiveness, it is preferable that both the overlapping surfaces are irradiated with VUV. That is, as shown in FIG. 3A, it is preferable that one surface 17A of the primary sheet 17 irradiated with VUV is overlapped so as to be in contact with the other primary sheet 17, but at this time, one of them may be overlapped. It is preferable that the other surface 17B of the other primary sheet 17 in contact with the surface 17A is also VUV-irradiated.
- the primary sheets 17 can be bonded by simply stacking them as described above, but in order to bond them more firmly, the primary sheets 17 may be pressurized in the stacking direction.
- the pressurization is preferably performed at a pressure such that the primary sheet 17 is not significantly deformed, and can be pressurized by using, for example, a roller or a press.
- the pressure is preferably 0.3 to 3 kgf / 50 mm.
- the laminated primary sheet 17 may be appropriately heated, for example, when pressurizing, but the primary sheet 17 activated by VUV irradiation can be adhered without heating, so that the laminated primary sheet 17 can be adhered without heating.
- the sheet 17 is preferably not heated. Therefore, the temperature at the time of pressing is, for example, 0 to 50 ° C., preferably about 10 to 40 ° C.
- the laminated block 18 is cut along the laminating direction (third direction) of the primary sheet 17 by the cutting tool 19 to obtain the heat conductive sheet 10.
- the laminated block 18 may be cut in a direction orthogonal to one direction (first direction) along the major axis direction of the scaly filler 12.
- a double-edged blade such as a razor blade or a cutter knife, a single-edged blade, a round blade, a wire blade, a saw blade, or the like can be used.
- the laminated block 18 is cut by using a cutting tool 19, for example, by a method such as pushing, shearing, rotating, or sliding.
- the direction along the major axis direction Y of the scaly filler 12 was the sheet thickness direction (first direction), but as shown in FIG. 4, the heat conduction in the present embodiment.
- the direction along the major axis direction Y (see FIG. 2) of the scaly filler 12 is one direction (second direction) perpendicular to the thickness direction of the sheet, and is along the horizontal axis direction X. The difference is that the direction is the thickness direction of the sheet (first direction).
- the thermal conductivity is improved not only in the thickness direction but also in one direction along the plane direction perpendicular to the thickness direction.
- the thermal conductivity in one direction (second direction) along the surface direction is the thickness direction (first direction).
- the heat conductive sheet 20 of the present embodiment can be suitably used in applications where high heat conductivity is required along the plane direction.
- the thermal conductivity in the first direction is preferably 2.5 W / (m ⁇ K) or more, more preferably 3 W / (m ⁇ K) or more, still more preferably 4.5 W / (m). ⁇ K) or more, and for example, 50 W / (m ⁇ K) or less.
- the thermal conductivity in the second direction is higher than the thermal conductivity in the first direction, for example, 5 W / (m ⁇ K) or more, preferably 8 W / (m ⁇ K) or more, more preferably 11 W / (m). ⁇ K) or more, and for example, 50 W / (m ⁇ K) or less.
- the thermal conductivity in the third direction is lower than the thermal conductivity in the first and second directions, preferably less than 4.5 W / (m ⁇ K), more preferably 3 W / (m ⁇ K). It is less than K), more preferably less than 2.5 W / (m ⁇ K), and more than, for example, 0.2 W / (m ⁇ K). Further, as described above, the thermal characteristic level in the second direction is preferably 10% or more, but usually exceeds 100%. Further, the weighted average value of the first aspect ratio of the scaly filler 12 and the aspect ratio of the fibrous filler 13 can be said to be the aspect ratio in the second direction / first direction in the present embodiment.
- the aspect ratio in the second direction / first direction in the present embodiment may be 1 or more, preferably 1.5 or more, more preferably 1.7 or more, and further 3 or more. It is preferably 8 or less, more preferably 7 or less, and even more preferably 5 or less.
- the heat conductive sheet 20 in the present embodiment may contain other fillers such as the fibrous filler 13 and the non-anisotropic filler as in the first embodiment.
- the fibrous filler 13 When the fibrous filler 13 is blended, the fibrous filler 13 may be oriented along the second direction in the fiber axial direction.
- the physical characteristics, dimensions, etc. of the sheet thickness, unit layer thickness 14L, heat conductive sheet type E hardness, and compressibility when compressed in the thickness direction at 0.276 MPa are the above-mentioned first items.
- the configurations of the other second embodiments are the same as those of the first embodiment, and detailed description thereof will be omitted.
- the method for manufacturing the heat conductive sheet 20 in the present embodiment is the same as that in the first embodiment, except that in the cutting step, the scaly filler 12 is cut in a direction orthogonal to one direction along the horizontal axis direction. Just do it.
- each unit layer 14 in the heat conductive sheet 20 has substantially the same composition as described above, but the composition of each unit layer 14 is different. They may be different from each other.
- each unit layer 14 does not have to have the same content of the scaly filler 12, or the scaly filler 12 and the fibrous filler 13, and the scaly filler 12 in some of the unit layers 14 does not have to have the same content.
- the content of the fibrous filler 13 may be different from the content of the scaly filler 12 or the fibrous filler 13 in the other unit layer 14.
- the content of the non-anisotropic filler in some unit layers 14 may be different from the content of the non-anisotropic filler in the other unit layers 14. Further, at least one of the scaly filler 12, the fibrous filler 13, and the non-anisotropic filler in some unit layers 14 may be different from these types in other unit layers 14. Good. Further, in the plurality of unit layers 14, not all unit layers 14 need to contain the scaly filler 12, and some unit layers 14 may contain the scaly filler 12, for example, a plurality of unit layers 14. At least one unit layer 14 of the unit layers 14 may contain a scaly filler 12.
- the scaly filler 12 along one direction in the first and second directions is contained in all the regions of the heat conductive sheet 20, and the heat conductive sheet 20 does not need to be contained. It is preferable that a scaly filler 12 along either the first or second direction is contained in a part.
- a part of the plurality of unit layers 14 may contain the fibrous filler 13, and the other may not contain the fibrous filler 13. Further, it is not necessary that a part of the plurality of unit layers 14 contains a non-anisotropic filler and the other does not contain a non-anisotropic filler.
- the thermal conductivity of some of the unit layers 14 can be changed to other unit layers. It may be made higher than the thermal conductivity of 14. In such a case, the unit layer 14 having a high thermal conductivity and the unit layer 14 having a low thermal conductivity may be arranged alternately, but it is not necessary to arrange them alternately.
- the conductivity of some unit layers 14 may be lower than the conductivity of other unit layers 14.
- the unit layer having high conductivity and the unit layer 14 having low conductivity may be arranged alternately, but it is not necessary to arrange them alternately.
- some unit layers 14 having a low conductivity prevent the conductivity along the third direction (see FIG. 1). Therefore, even in the entire thermal conductive sheet 20, the conductivity in the third direction becomes low, and it becomes easy to secure the insulating property.
- the unit layer 14 having a low conductivity may not contain the conductive heat conductive filler but may contain the insulating heat conductive filler. preferable.
- a part of the plurality of unit layers 14 may be a unit layer 14 having a relatively high thermal conductivity, and the other part may be a unit layer 14 having a light transmittance.
- the unit layer 14 having thermal conductivity is a layer containing a thermally conductive filler such as a thermally conductive filler and a scaly filler 12 as described above.
- the light-transmitting unit layer 14 may be, for example, a layer that does not contain a heat conductive filler. According to such a configuration, the entire heat conductive sheet 20 also has constant heat conductivity and light transmission along the thickness direction.
- the unit layer 14 having thermal conductivity and the unit layer 14 having light transmittance may be arranged alternately, but it is not necessary to arrange them alternately.
- orientation directions of the scaly filler 12 of each unit layer 14 in the major axis direction Y need not all be aligned in the same direction (that is, one direction in the first and second directions). That is, in the present invention, in at least a part of the unit layers 14, the orientation direction in the major axis direction Y is either the first direction or the second direction, and the orientation direction in the horizontal axis direction X is the first direction. Or it may be the other in the second direction.
- the first directions in each unit layer 14 may be sequentially laminated so as to be 90 ° to each other or changed at an arbitrary angle.
- the composition other than the heat conductive filler may be changed for each unit layer 14.
- the type of the polymer matrix 11 of some unit layers 14 may be changed from the type of the polymer matrix 11 of another unit layer 14.
- the presence / absence of the additive component in some of the unit layers 14, the type and amount of the additive components, and the like may be different from those of the other unit layers 14.
- the hardness of some unit layers 14 is hardened. The hardness (type E hardness or type OO hardness) may be different from the hardness of the other unit layer 14.
- the evaluation method in this example is as follows. [Measurement of viscosity of liquid composition (mixture)] The viscosities of the liquid compositions of each example were measured with a viscometer (rotational viscometer DV-E manufactured by BROOKFIELD) using a rotor of the spindle SC4-14 at a rotation speed of 1 rpm and a measurement temperature of 25 ° C. The results are shown in Table 1.
- the thermal conductivity in the thickness direction (first direction) of the produced thermally conductive sheet was measured by a method according to ASTM D5470-06.
- the thermal conductivity in the second direction and the third direction was also measured by a method according to ASTM D5470-06.
- the results are shown in Table 1.
- the thermal conductivity in the second direction is a thermal conductivity measured by cutting a test piece (thickness 2 mm) obtained by cutting a laminated block of each example described later so that the second direction is the thickness direction.
- the thermal conductivity in the third direction is the thermal conductivity measured by measuring the primary sheet (thickness 2 mm) of each example.
- the level of thermal properties in the second direction is shown as a percentage.
- Type E hardness The Type E hardness was measured according to the regulations of ASTM D2240-05 as a 10 mm test piece by stacking five heat conductive sheets and primary sheets obtained in each Example and Comparative Example. The results are shown in Table 1.
- Example 1 As a curable silicone composition, an alkenyl group-containing organopolysiloxane (main agent) and a hydrogen organopolysiloxane (curing agent) (total 100 parts by mass, volume filling rate 38% by volume), and boron nitride powder as a scaly filler.
- the liquid composition was unidirectionally coated on a base film made of polyethylene terephthalate (PET) at 25 ° C. using a bar coater as a coating applicator.
- the scaly filler was oriented so that the major axis direction X was along the coating direction, the horizontal axis direction X was one direction in the sheet surface direction, and the direction was perpendicular to the coating direction.
- the applied liquid composition was heated at 120 ° C. for 0.5 hours to cure the liquid composition, thereby obtaining a primary sheet having a thickness of 2 mm.
- VUV irradiator (trade name: Excimer MINI, manufactured by Hamamatsu Photonics Co., Ltd.) was used on both sides of each of the obtained primary sheets, and the integrated light amount was 20 mJ / on the surface of the primary sheet in the air at room temperature (25 ° C.). VUV was irradiated under the condition of cm 2. Next, 100 VUV-irradiated primary sheets were laminated and pressed by a roller at a pressure of 1.6 kgf / 50 mm in an environment of 25 ° C. to obtain a laminated block.
- the obtained laminated block is sliced by a cutter blade parallel to the laminating direction and perpendicular to the direction along the long axis direction of the scaly filler, and each unit layer has a thickness of 2 mm and a sheet thickness of 2 mm.
- the heat conductive sheet of was obtained.
- the scaly filler has a major axis direction along the thickness direction (first direction) and a horizontal axis direction perpendicular to the first direction in the sheet surface direction (second direction). It was oriented along. The same was true for each of the following examples.
- the volume filling rate of the silicone resin is 38% by volume
- the volume filling rate of the scaly filler is 23% by volume
- the volume filling rate of the non-isometric filler is 39% by volume
- the viscosity of the liquid composition at 25 ° C. is 600 Pa. ⁇ It was s.
- the volume filling rate of the silicone resin and each filler was the same as in Example 2, and the viscosity of the liquid composition at 25 ° C. was 750 Pa ⁇ s.
- Example 5 In the preparation of the liquid composition, graphitized carbon fibers (average fiber length 100 ⁇ m, aspect ratio 10, thermal conductivity 500 W / (m ⁇ K)) are further blended as the fibrous filler, and the number of parts of each filler is blended. It was carried out in the same manner as in Example 4 except that the changes were made as described in Table 1. The fibrous filler was oriented so that the fiber axis direction was along the thickness direction (first direction), and the same was true in the following Examples and Comparative Examples.
- the volume filling rate of the silicone resin is 38% by volume
- the volume filling rate of the scaly filler is 9% by volume
- the volume filling rate of the fibrous filler is 14% by volume
- the volume filling rate of the non-anisometric filler is 39 volumes. %
- the viscosity of the liquid composition at 25 ° C. was 750 Pa ⁇ s.
- Example 6 In the preparation of the liquid composition, the same procedure as in Example 5 was carried out except that the number of copies of each filler was changed as shown in Table 1.
- the volume filling rate of the silicone resin is 38% by volume
- the volume filling rate of the scaly filler is 14% by volume
- the volume filling rate of the fibrous filler is 9% by volume
- the volume filling rate of the non-anisometric filler is 39 volumes. %
- the viscosity of the liquid composition at 25 ° C. was 540 Pa ⁇ s.
- Example 7 In the preparation of the liquid composition, the same procedure as in Example 4 was carried out except that the number of copies of each filler was changed as shown in Table 1.
- the volume filling rate of the silicone resin is 38% by volume
- the volume filling rate of the scaly filler is 22% by volume
- the volume filling rate of the non-isometric filler is 40% by volume
- the viscosity of the liquid composition at 25 ° C. is 960 Pa. ⁇ It was s.
- Example 1 In the preparation of the liquid composition, the same procedure as in Example 1 was carried out except that the scaly filler was not used and the number of copies of each filler was changed as shown in Table 1.
- the volume filling rate of the silicone resin is 37% by volume
- the volume filling rate of the fibrous filler is 20% by volume
- the volume filling rate of the non-anisometric filler is 43% by volume
- the viscosity of the liquid composition at 25 ° C. is 360 Pa. It was s.
- Example 2 In the preparation of the liquid composition, the same procedure as in Example 1 was carried out except that the scaly filler was not used and the number of copies of each filler was changed as shown in Table 1.
- the volume filling rate of the silicone resin is 38% by volume
- the volume filling rate of the fibrous filler is 22% by volume
- the volume filling rate of the non-anisometric filler is 40% by volume
- the viscosity of the liquid composition at 25 ° C. is 450 Pa. It was s.
- the scaly filler is contained, and the scaly filler is arranged along the major axis direction Y in the first direction and the horizontal axis direction X along the second direction.
- the thermal conductivity was improved not only in the thickness direction (first direction) but also in one direction (second direction) along the surface direction. Therefore, the thermal conductivity in one direction along the thickness direction and the surface direction is improved, and the thermal resistance in these directions is lowered.
- the thermal conductive sheet of each comparative example did not contain a scaly filler in which the major axis direction Y was oriented in the first direction and the horizontal axis direction X was oriented in the second direction. , The thermal conductivity in both the thickness direction and the one direction along the plane direction was not improved, so that the thermal resistance values in both the thickness direction and the one direction along the plane direction could not be lowered.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Composite Materials (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Combustion & Propulsion (AREA)
- Thermal Sciences (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Manufacture Of Macromolecular Shaped Articles (AREA)
- Ceramic Engineering (AREA)
- Moulding By Coating Moulds (AREA)
- Cooling Or The Like Of Electrical Apparatus (AREA)
Abstract
Description
熱伝導性シートは、一般的には、高分子マトリクスと、高分子マトリクス中に分散された熱伝導性充填材とを含有する。また、熱伝導性シートは、特定の方向の熱伝導性を高めるために、形状に異方性を有する異方性充填材を一方向に配向することがある。
そうした一方で、従来の流動配向法などにより得られる、異方性充填材をシートの厚さ方向に配向した熱伝導シートは、発熱体で生じた熱を放熱体に伝える効率に優れるものの、シートの面方向に沿う方向に熱伝導性が高めることが難しい。
[1]高分子マトリクス中に鱗片状充填材を含む熱伝導性シートであって、
前記鱗片状充填材が、鱗片面の長軸方向が、前記熱伝導性シートの厚さ方向である第1の方向及び前記第1の方向に垂直である第2の方向のいずれか一方に沿い、かつ前記鱗片面において長軸方向に垂直となる横軸方向が、前記第1の方向及び前記第2の方向の他方に沿うように配向する、熱伝導性シート。
[2]前記鱗片状充填材は、前記長軸方向が前記第1の方向に沿い、かつ前記横軸方向が前記第2の方向に沿うように配向する上記[1]に記載の熱伝導性シート。
[3]前記鱗片状充填材は、前記横軸方向が前記第1の方向に沿い、かつ前記長軸方向が前記第2の方向に沿うように配向する、上記[1]に記載の熱伝導性シート。
[4]前記鱗片状充填材の前記横軸方向の長さに対する、前記長軸方向の長さの比(長軸方向の長さ/横軸方向の長さ)で表される第1のアスペクト比が1.5以上である上記[1]~[3]のいずれかに記載の熱伝導性シート。
[5]前記鱗片状充填材の平均粒径が20μm以上である上記[1]~[4]のいずれかに記載の熱伝導性シート。
[6]前記鱗片状充填材が、鱗片状黒鉛粉末を含む上記[1]~[5]のいずれかに記載の熱伝導性シート。
[7]前記鱗片状充填材が、鱗片状窒化ホウ素粉末を含む上記[1]~[6]のいずれかに記載の熱伝導性シート。
[8]前記高分子マトリクス中にさらに繊維状充填材を含む上記[1]~[7]のいずれかに記載の熱伝導性シート。
[9]前記繊維状充填材が、炭素繊維である上記[8]に記載の熱伝導性シート。
[10]複数の単位層を有し、かつ前記複数の単位層のうち、少なくとも1つが前記鱗片状充填材を含み、
複数の単位層が、前記第1及び第2の方向に垂直な第3の方向に沿って積層される上記[1]~[9]のいずれかに記載の熱伝導性シート。
[11]前記高分子マトリクス中にさらに非異方性充填材を含有する上記[1]~[10]のいずれかに記載の熱伝導性シート。
[12]上記[1]~[11]のいずれか1項に記載の熱伝導性シートの製造方法であって、
前記高分子マトリクスの前駆体である樹脂と、前記鱗片状充填材とを含む混合物を調製する工程と、
前記混合物を流動配向処理して、前記鱗片状充填材を配向させつつ、1次シートを得る工程と、
前記1次シートを積層して積層ブロックを得る工程と、
前記積層ブロックを積層方向に沿って切断する工程と
を備える熱伝導性シートの製造方法。
[第1の実施形態]
図1は、第1の実施形態の熱伝導性シート10の模式図、図2は、鱗片状充填材12の詳細を説明するための模式図である。第1の実施形態に係る熱伝導性シート10は、高分子マトリクス11と、高分子マトリクス11中に分散される鱗片状充填材12とを含む。図2に示すように、鱗片状充填材12は、鱗片面において長さ方向を長軸方向Yとし、鱗片面において長軸方向に垂直となる方向を横軸方向X、これら長軸方向Yと横軸方向Xに垂直で、鱗片状充填材12の厚さ方向を厚さ方向Zとする。鱗片状充填材12は、熱伝導性シート10の熱伝導性を高める熱伝導性充填材である。
熱伝導性シート10は、厚さ方向に加えて、面方向における一方向にも熱伝導性が良好となることで、放熱効果を高めつつ、面方向にも熱を逃がしてヒートスポットを生じにくくする。さらに、面方向における一方向以外の方向には、熱伝導性がそれほど高められないので、例えば基板上に耐熱性の低い素子が存在する場合には、その方向に伝熱しないようにすることも可能になる。
なお、本明細書において、異方性充填材とは、形状に異方性を有する充填材であり、配向が可能な充填材である。異方性充填材は、通常は、いずれかのアスペクト比が2より大きくなる。また、非異方性充填材は、形状に異方性を実質的に有しない充填材であり、後述する剪断力作用下など、異方性充填材が所定の方向に配向する環境下においても、その所定の方向に配向しない充填材である。非異方性充填材は、後述する通り、例えば、そのアスペクト比が2以下となるものである。
(高分子マトリクス)
高分子マトリクス11は、鱗片状充填材12等の熱伝導性充填材を保持する部材であり、柔軟なゴム状弾性体でなることが好ましい。高分子マトリクスは、その前駆体である樹脂から形成される。なお、本明細書でいう前駆体とは、後述するように反応することで高分子マトリクス11となる物質のみならず、反応せず高分子マトリクス11と同一の物質も含む概念である。
鱗片状充填材12等の異方性充填材を配向した状態で高分子マトリクス11中に含有させるためには、配向させる工程の際に樹脂が流動性を有していることが要求される。例えば、高分子マトリクス11の前駆体である樹脂が熱可塑性樹脂であれば、加熱して可塑化した状態で異方性充填材を配向させることができる。また、反応性液状樹脂であれば、硬化前に異方性充填材を配向させて、その状態を維持したまま硬化すれば、異方性充填材が配向した硬化物を得ることができる。熱可塑性樹脂は比較的粘度が高く、また低粘度になるまで可塑化すると樹脂が熱劣化するおそれがあるため、反応性液状樹脂を採用することが好ましい。
硬化剤は、ヒドロシリル基の数や分子量、主剤に対する配合量比を適宜調整することで、後述する1次シートの硬さを調整できる。具体的には、1分子中のヒドロシリル基が少ないか、分子量の大きい硬化剤を用いたり、主剤に対する硬化剤の配合量比を少なくしたりすることで、1次シートの硬さを低くできる。
鱗片状充填材12は、横軸方向Xの長さに対する、長軸方向Yの長さの比(長軸方向Yの長さ/横軸方向Xの長さ)で表される第1のアスペクト比が、1.5以上であることが好ましい。
上記第1のアスペクト比を1.5以上とすることで、第1の方向(厚さ方向)の熱伝導性を、第2の方向(面方向の一方向)の熱伝導性よりも有意に高くできる。これにより、面方向に必要以上に伝熱することを防止しつつ、厚さ方向の熱伝導性が高められ、放熱効果を高めやすくなる。また、第1の方向(厚さ方向)の熱伝導性を、面方向に沿う熱伝導性よりも十分に高くする観点からは、第1のアスペクト比は、1.7以上がより好ましい。
ただし、第1のアスペクト比は、1以上であればよく、第1のアスペクト比が例えば、1.5未満であると、第1の方向と第2の方向の熱伝導性に有意に差をつけることが難しくなるが、厚さ方向及び面方向の両方に高い熱伝熱性が要求される用途には好適である。
第1のアスペクト比は、第2の方向にも一定以上の熱伝導性を付与するために、例えば5以下、好ましくは3以下、より好ましくは2.5以下である。
また、鱗片状充填材12の嵩が低くなり、高分子マトリクス11に高充填としやすくする観点から、鱗片状充填材12の平均粒径は、400μm以下が好ましく、300μm以下がより好ましく、200μm以下がさらに好ましく、150μm以下がよりさらに好ましい。
鱗片状充填材12は、1種単独で使用してもよいし、2種以上を併用してもよい。例えば、鱗片状充填材12として、少なくとも2つの互いに異なる平均粒径を有するものを使用してもよい。
同様に、任意の50個の鱗片状充填材12の長軸方向Yの長さ、横軸方向Xの長さ、及び厚さ方向Zの長さ(すなわち、厚さ)を測定して、平均値(相加平均値)の比により、第1及び第2のアスペクト比を求めるとよい。
なお、本明細書において、任意のものとは無作為に選んだものをいう。
鱗片状黒鉛粉末は、グラファイトの結晶面が鱗片面の面内方向に連なっており、その面内方向に高い熱伝導率を備える。そのため、その鱗片面を所定の方向に揃えることで、特定方向の熱伝導率を高めることができる。鱗片黒鉛粉末は、高い黒鉛化度をもつものが好ましい。
なお、熱伝導性シート10は、上記のとおり、繊維状充填材13などの他の異方性充填材と併用してもよいが、鱗片状充填材12を繊維状充填材13と併用する場合の鱗片状充填材12と繊維状充填材13の合計量の好適値は後述する通りである。
ここで、長軸方向Yが第1の方向に沿うとは、熱伝導性シート10の第1の方向に対して長軸方向Yのなす角度(配向角度)が30°未満の鱗片状充填材12の数の割合が、鱗片状充填材全量に対して、50%を超える状態にあることをいい、該割合は、好ましくは80%を超える。
また、横軸方向Xが第2の方向に沿うとは、熱伝導性シート10の第2の方向に対して横軸方向Xのなす角度が30°未満の鱗片状充填材12の数の割合が、鱗片状充填材全量に対して、50%を超える状態にあることをいい、該割合は、好ましくは80%を超える。
なお、第1の方向の熱伝導率を高める観点から、鱗片状充填材12の第1の方向に対する長軸方向Yのなす角度(配向角度)は、0°以上30°未満とすることが好ましく、該角度は、一定数(例えば、任意の鱗片状充填材12を50個)の鱗片状充填材12の配向角度の平均値である。
また、第2の方向における熱伝導率を高める観点から、鱗片状充填材12の第2の方向に対する横軸方向Xのなす角度は、0°以上30°未満とすることが好ましく、該角度は、一定数(例えば、任意の鱗片状充填材12を50個)の鱗片状充填材12がなす角度の平均値である。
熱伝導性シート10は、上記のとおり、高分子マトリクス11に分散される繊維状充填材13を含有することが好ましい。繊維状充填材13は、その繊維軸方向を第1の方向に配向させやすくして熱伝導性を高める観点から、アスペクト比が、4以上であることが好ましく、7~100であることがより好ましく、15~50であることがさらに好ましい。なお、アスペクト比は、繊維状充填材13の繊維軸方向の長さ(繊維長)/繊維の直径を意味する。
したがって、鱗片状充填材12の第1のアスペクト比と、繊維状充填材13のアスペクト比の加重平均値(「第1の方向/第2の方向のアスペクト比」ともいう)は、異方性充填材が第2の方向に対して、第1の方向にどの程度配向しているかを示す比率ともいえる。
なお、アスペクト比の加重平均値とは、各異方性充填材のアスペクト比(鱗片状充填材12であれば第1のアスペクト比、繊維状充填材13であればアスペクト比)に配合量(体積比率)を加重させて平均した値である。
第1の方向/第2の方向のアスペクト比は、具体的には、1以上であればよいが、1.5以上が好ましく、1.7以上がより好ましく、3以上がさらに好ましい。このアスペクト比を1.5以上にすると、本実施形態では厚さ方向の熱伝導率が高くなり、電子機器などに使用した場合の放熱効果が高くなる。また、第1の方向/第2の方向のアスペクト比は、例えば8以下であることが好ましく、7以下がより好ましく、5以下がさらに好ましい。このアスペクト比を8以下とすると、本実施形態では面方向の熱伝導率が高くなり、ヒートスポットなどを防止しやすくなる。
なお、上記の平均繊維長は、繊維状充填材13を顕微鏡で観察して算出することができる。例えば、熱伝導性シート10のマトリクス成分を溶かして分離した繊維状充填材13について、電子顕微鏡や光学顕微鏡を用いて、任意の50個の繊維状充填材13の繊維長を測定して、その平均値(相加平均値)を平均繊維長とすることができる。この際、繊維を粉砕しないように大きなシェアがかからないようにする。また、熱伝導性シート10から繊維状充填材13を分離することが難しい場合は、X線CT装置を用いて、繊維状充填材13の繊維長を測定して、平均繊維長を算出してもよい。
また、繊維状充填材13の直径についても同様に電子顕微鏡や光学顕微鏡、X線CT装置を用いて測定することができる。
炭素繊維としては、黒鉛化炭素繊維が好ましい。黒鉛化炭素繊維は、グラファイトの結晶面が繊維軸方向に連なっており、その繊維軸方向に高い熱伝導率を備える。そのため、その繊維軸方向を所定の方向に揃えることで、特定方向の熱伝導率を高めることができる。黒鉛化炭素繊維は、高い黒鉛化度をもつものが好ましい。
黒鉛化炭素繊維におけるメソフェーズピッチの使用態様は、紡糸可能ならば特に限定されず、メソフェーズピッチを単独で用いてもよいし、他の原料と組み合わせて用いてもよい。ただし、メソフェーズピッチを単独で用いること、すなわち、メソフェーズピッチ含有量100%の黒鉛化炭素繊維が、高熱伝導化、紡糸性及び品質の安定性の面から最も好ましい。
繊維状充填材13は、1種単独で使用してもよいし、2種以上を併用してもよい。例えば、繊維状充填材13として、少なくとも2つの互いに異なる平均繊維長を有する充填材を使用してもよい。
なお、繊維状充填材13の配向方向は、熱伝導率を高める観点から、第1の方向に対する繊維状充填材13の繊維軸方向のなす角度(配向角度)を0°以上5°未満とすることが好ましく、該角度は、一定数(例えば、任意の繊維状充填材13を50個)の繊維状充填材13の配向角度の平均値である。
これら観点から、熱伝導性シート10における鱗片状充填材12と繊維状充填材13との上記合計含有量は、50~350質量部であることがより好ましく、80~250質量部であることがより好ましい。また、上記の合計含有量は、体積基準の充填率(体積充填率)で表すと、熱伝導性シート全量に対して、好ましくは2~50体積%、より好ましくは8~40体積%であり、さらに好ましくは15~30体積%である。
また、鱗片状充填材12及び繊維状充填材13は、導電性を有していてもよいし、絶縁性を有していてもよい。鱗片状充填材12及び繊維状充填材13が絶縁性を有すると、本実施形態では熱伝導性シート10の厚さ方向の絶縁性を高めることができるため、電気機器において好適に使用することが可能になる。なお、本発明において導電性を有するとは例えば体積抵抗率が1×109Ω・cm以下の場合をいうものとする。また、絶縁性を有するとは例えば体積抵抗率が1×109Ω・cmを超える場合をいうものとする。
熱伝導性シート10は、上記のとおり、高分子マトリクス11中に、非異方性充填材(図示しない)を含有することが好ましい。非異方性充填材は、鱗片状充填材12などの異方性充填材とともに熱伝導性シート10に熱伝導性を付与する材料である。非異方性充填材が含有されることで、配向した鱗片状充填材12などの異方性充填材の間に当該充填材が介在し、熱伝導率のより高い熱伝導性シートが得られる。
非異方性充填材は、形状に異方性を実質的に有しない充填材であり、後述する剪断力作用下など、鱗片状充填材12などの異方性充填材が所定の方向に配向する環境下においても、その所定の方向に配向しない充填材である。
非異方性充填材において、金属としては、アルミニウム、銅、ニッケルなど、金属酸化物としては、アルミナに代表される酸化アルミニウム、酸化マグネシウム、酸化亜鉛など、金属窒化物としては窒化アルミニウムなどを例示することができる。金属水酸化物としては、水酸化アルミニウムが挙げられる。さらに、炭素材料としては球状黒鉛などが挙げられる。金属以外の酸化物、窒化物、炭化物としては、石英、窒化ホウ素、炭化ケイ素などが挙げられる。上記した中では、絶縁性を有する非異方性充填材として、金属酸化物、金属窒化物、金属水酸化物、金属炭化物が挙げられる。
また、非異方性充填材は、上記した中でも、酸化アルミニウム及びアルミニウムは、熱伝導率が高く、球状のものが入手しやすい点で好ましく、水酸化アルミニウムは入手し易く熱伝導性シートの難燃性を高めることができる点で好ましい。これらのなかでは、酸化アルミニウムがより好ましい。
なお、非異方性充填材の平均粒径は、電子顕微鏡等で観察して測定できる。より具体的には、鱗片状充填材12及び繊維状充填材13における測定と同様に電子顕微鏡や光学顕微鏡、X線CT装置を用いて、任意の非異方性充填材50個の粒径を測定して、その平均値(相加平均値)を平均粒径とすることができる。
非異方性充填材は、1種単独で使用してもよいし、2種以上を併用してもよい。なお、各充填材の平均粒径とは、各充填材を2種以上含むときはそれらを区別せずに算出した値とする。
なお、非異方性充填材の含有量は、体積%で表すと、熱伝導性シート全量に対して、10~75体積%が好ましく、30~60体積%がより好ましく、35~50体積%がさらに好ましい。
熱伝導性シート10において、高分子マトリクス11には、さらに熱伝導性シート10としての機能を損なわない範囲で種々の添加剤を配合させてもよい。添加剤としては、例えば、分散剤、カップリング剤、粘着剤、難燃剤、酸化防止剤、着色剤、沈降防止剤などから選択される少なくとも1種以上が挙げられる。また、上記したように硬化性シリコーン組成物を硬化させる場合には、添加剤として硬化を促進させる硬化触媒などが配合されてもよい。硬化触媒としては、白金系触媒が挙げられる。
熱伝導シート10は、特に限定されないが、後述の製造方法で製造されることで、複数の単位層14からなる。熱伝導シート10における各単位層14は鱗片状充填材12を含有する。複数の単位層14は、図1に示すように、第3の方向に沿って積層されており、隣接する単位層14同士が互いに接着されている。
また、各単位層14は、実質的に同一の組成を有する。したがって、各単位層14における鱗片状充填材12、繊維状充填材13、非異方性充填材、及び高分子マトリクスの含有量は、熱伝導性シートにおける含有量と同様であり、各単位層14における鱗片状充填材12、繊維状充填材13、非異方性充填材、及び高分子マトリクス11の含有量及び充填率も、上記で述べたとおりとなる。
熱伝導性シート10の第1の方向の熱伝導率は、例えば5W/(m・K)以上であり、8W/(m・K)以上とすることが好ましく、11W/(m・K)以上がより好ましい。これら下限値以上とすることで、熱伝導性シート10の厚さ方向における熱伝導性を優れたものにできる。上限は特にないが、熱伝導性シート10の厚さ方向の熱伝導率は、例えば50W/(m・K)以下である。なお、熱伝導率はASTM D5470-06に準拠した方法で測定するものとする。
また、第2の方向の熱特性レベルは、100%以下であってもよいが、厚さ方向の熱伝導性を面方向の熱伝導性よりも高めて放熱性を優れたものとする観点から、90%以下が好ましく、80%以下がより好ましい。
第2の方向の熱特性レベル(%)=(λ2-λ3)/(λ1-λ3)×100
λ1:第1の方向の熱伝導率
λ2:第2の方向の熱伝導率
λ3:第3の方向の熱伝導率
また、凹凸の大きな被着体に用いる場合などは極めて柔軟なことが好ましく、熱伝導性シート10のタイプOO硬さは、62以下であることが好ましい。熱伝導性シート10は、タイプOO硬さが62以下となることで、極めて柔軟な熱伝導性シートとなり、発熱体と放熱体などに対する追従性が極めて良好となる。また、柔軟性を向上させて、追従性などを優れたものとする観点から、熱伝導性シート10のタイプOO硬さは、好ましくは50以下、より好ましくは45以下である。一方、熱伝導性シート10のタイプOO硬さは、特に限定されないが、例えば15以上、好ましくは18以上、より好ましくは25以上である。
また、熱伝導性シート10の取扱性を優先する場合は、熱伝導性シート10のタイプE硬さで15以上であることが好ましく、35以上であることが特に好ましい。熱伝導性シート10の硬さが柔らかいほど、圧縮したときに発熱体や放熱体またはそれらが配置される基板等への応力を小さくできるため好ましいが、硬さをタイプOO硬さで15以上とすることで、熱伝導性シート10が所定の取扱性を良くして、被着体へ貼着しやすいものとすることができる。特にタイプE硬さで35以上とすれば、取扱性と柔らかさのバランスに優れるものとすることができる。
なお、上記タイプE硬さおよびタイプOO硬さはASTM D2240-05に規定された方法に従って、所定のデュロメータを用いて測定される値である。
ただし、両表面10A,10Bのいずれか一方又は両方は、異方性充填材が露出せずに粘着面となってもよい。
なお、圧縮率は、例えば熱伝導性シートを、10mm×10mmのサイズでカットして、表面が平坦な台座と、平行に押圧する押圧子の間に試験片を挟んで測定するとよい。
本実施形態における熱伝導性シート10は、上記の通り、第1の方向(厚さ方向)に高い熱伝導性を有するので放熱性に優れ、かつ面方向に一定の熱伝導性を有するので、ヒートスポットなどが生じるのを防止しやすくなる。さらに、面方向における一方向以外の方向には、熱伝導性は高められないので、例えば電子機器内部に耐熱性の低い素子が存在する場合には、その方向に伝熱しないようにすることも可能になる。
次に、上記した熱伝導性シート10の製造方法の一例について説明する。
本製造方法は、高分子マトリクスの前駆体である樹脂と、熱伝導性充填材として少なくとも鱗片状充填材12とを含む混合物を調製する混合物調製工程と、上記した混合物を流動配向処理して、鱗片状充填材12などの異方性充填材を配向させつつ、1次シートを得る1次シート準備工程と、1次シートを積層して積層ブロックを得る積層工程と、積層ブロックを積層方向に沿って切断する切断工程とを備える。以下、各工程について詳細に説明する。
混合物調製工程では、高分子マトリクスの前駆体である樹脂(例えばシリコーン樹脂であれば、硬化性シリコーン組成物)と、鱗片状充填材12を含む混合物(液状組成物)を調製する。混合物には、さらに繊維状充填材13、非異方性充填材が適宜配合されてもよく、さらに添加成分が配合されてもよい。液状組成物は、通常スラリーとなる。液状組成物を構成する各成分の混合は、例えば公知のニーダー、混練ロール、ミキサーなどを使用するとよい。
なお、粘度とは、回転粘度計(ブルックフィールド粘度計DV-E、スピンドルSC4-14)を用いて、回転速度1rpmで測定された粘度であり、測定温度は液状組成物の塗工時の温度である。
1次シート準備工程では、液状組成物を、剪断力を付与しながらシート状に成形し、1次シートを得る。液状組成物は、例えば、バーコータ又はドクターブレード等の塗布用アプリケータ、もしくは、押出成形やノズルからの吐出等により、基材フィルム上に塗工するとよく、このような方法により、液状組成物の塗工方向(流動方向)に沿った剪断力を与えることができる。このように剪断力を付与しながらシート状に成形することで、鱗片状充填材12が、長軸方向Yが流動方向(シート面方向における一方向)に沿い、かつ横軸方向Xが流動方向に垂直である方向(シート面方向における他の方向)に沿うように配向する。また、液状組成物に繊維状充填材が配合される場合には、繊維状充填材13は、その繊維軸方向が流動方向に沿うように配向される。
また、液状組成物の硬化は、液状組成物に例えば硬化性シリコーン組成物が含まれる場合には、硬化性シリコーン組成物を硬化することで行う。液状組成物の硬化は、加熱により行うとよいが、例えば、50~150℃程度の温度で行うとよい。また、加熱時間は、例えば10分~3時間程度である。なお、硬化性の液状組成物に溶剤が配合される場合には、溶剤は硬化時の加熱により揮発させるとよい。
また、得られる熱伝導性シート10の柔軟性を確保する観点から、1次シートのタイプOO硬さは、55以下が好ましく、50以下がより好ましく、40以下がさらに好ましい。
また、得られる熱伝導性シート10の取扱性を高める観点からは、1次シートのタイプE硬さは、70以下が好ましく、40以下がより好ましい。また、1次シートのタイプE硬さは、10以上が好ましく、30以上がより好ましい。
次に、1次シート準備工程で得られた複数の1次シート17を、異方性充填材の配向方向が同じになるように積層する(図3(a)及び(b)参照)。すなわち、上記した鱗片状充填材12の長軸方向Yが沿う一方向、横軸方向Xが沿う他の方向それぞれが、複数の1次シート17の間で互いに一致するように積層される。そして、積層された複数の1次シート17を互いに接着させ一体化させて積層ブロック18を得る。例えば、積層された複数の1次シート17は、樹脂が熱可塑性樹脂である場合、プレス成形により、1次シート17中の高分子マトリクス11を溶融固着させて積層ブロック18を形成するとよい。また、1次シート17、17間に公知の接着剤などを配置させて1次シート17、17間を接着させてもよい。
さらに、高分子マトリクスの前駆体が、硬化性である場合には、半硬化された複数の1次シート17を積層して、積層後に各1次シート17を全硬化して、その全硬化により1次シート17を互いに接着させ一体化させて積層ブロック18としてもよい。
VUV照射条件は、1次シート17の表面を活性化できる条件であれば特に限定されないが、例えば積算光量が5~100mJ/cm2、好ましくは積算光量が10~50mJ/cm2となるようにVUVを照射するとよい。
すなわち、図3(a)に示すように、1次シート17は、VUV照射された一方の面17Aを、他の1次シート17に接触するように重ね合わせるとよいが、この際、一方の面17Aに接触する、他の1次シート17の他方の面17BもVUV照射されることが好ましい。
積層された1次シート17は、例えば加圧するときなどに適宜加熱されてもよいが、VUV照射により活性化された1次シート17は、加熱しなくても接着できるので、積層された1次シート17は、加熱しないことが好ましい。したがって、プレス時の温度は、例えば0~50℃、好ましくは10~40℃程度である。
次に、図3(c)に示すように、刃物19によって、積層ブロック18を1次シート17の積層方向(第3の方向)に沿って切断し、熱伝導性シート10を得る。この際、積層ブロック18は、鱗片状充填材12の長軸方向が沿う一方向(第1の方向)に直交する方向に切断するとよい。刃物19としては、例えば、カミソリ刃やカッターナイフ等の両刃や片刃、丸刃、ワイヤー刃、鋸刃等を用いることができる。積層ブロック18は、刃物19を用いて、例えば、押切、剪断、回転、摺動等の方法により切断される。
次に、本発明の第1の実施形態について図4を用いて説明する。
第1の実施形態では、鱗片状充填材12の長軸方向Yに沿う方向がシートの厚さ方向(第1の方向)であったが、図4に示すように、本実施形態における熱伝導性シート20では、鱗片状充填材12の長軸方向Y(図2参照)に沿う方向が、シートの厚さ方向に垂直である一方向(第2の方向)となり、横軸方向Xに沿う方向が、シートの厚さ方向(第1の方向)となる点において相違する。
このような構成により、本実施形態でも、第1の実施形態と同様に、厚さ方向のみならず、厚さ方向に垂直な面方向に沿う一方向にも熱伝導性が良好となる。ただし、鱗片状充填材12の長軸方向Yに沿う方向が第2の方向であるので、面方向に沿う一方向(第2の方向)の熱伝導性が厚さ方向(第1の方向)の熱伝導性よりも高くなる。そのため、本実施形態の熱伝導性シート20は、面方向に沿って高い熱伝導性が必要とされる用途において好適に使用できる。
第2の方向における熱伝導率は、第1の方向における熱伝導率よりも高く、例えば5W/(m・K)以上、好ましくは8W/(m・K)以上、より好ましくは11W/(m・K)以上であり、また、例えば50W/(m・K)以下である。
第3の方向の熱伝導率は、第1の方向および第2の方向の熱伝度率よりも低くなり、好ましくは4.5W/(m・K)未満、より好ましくは3W/(m・K)未満であり、さらに好ましくは2.5W/(m・K)未満であり、また、例えば0.2W/(m・K)以上である。また、第2の方向における熱特性レベルは、上記のとおり、10%以上が好ましいが、通常は100%を超える。
さらに、鱗片状充填材12の第1のアスペクト比と、繊維状充填材13のアスペクト比の加重平均値は、本実施形態では、第2の方向/第1の方向のアスペクト比といえる。本実施形態における第2の方向/第1の方向のアスペクト比は、具体的には、1以上であればよいが、1.5以上が好ましく、1.7以上がより好ましく、3以上がさらに好ましく、8以下であることが好ましく、また、7以下がより好ましく、5以下がさらに好ましい。
また、シートの厚さ、単位層の厚さ14L、熱伝導性シートのタイプE硬さ及び0.276MPaで厚さ方向に圧縮したときの圧縮率などの各物性、寸法などは上記の第1の実施形態で説明したとおりであり、その他の第2の実施形態における各構成も、上記第1の実施形態と同様であり、その詳細な説明は省略する。
なお、本実施形態における熱伝導シート20の製造方法は、切断工程において、鱗片状充填材12の横軸方向が沿う一方向に直交する方向に切断する点以外は、第1の実施と同様に行えばよい。
例えば、各単位層14は、鱗片状充填材12、又は鱗片状充填材12及び繊維状充填材13の含有量が互いに同一である必要はなく、一部の単位層14における鱗片状充填材12又は繊維状充填材13の含有量を、他の単位層14における鱗片状充填材12又は繊維状充填材13の含有量と異ならせてもよい。同様に、一部の単位層14における非異方充填材の含有量も、他の単位層14における非異方性充填材の含有量と異ならせてもよい。また、一部の単位層14における鱗片状充填材12、繊維状充填材13、及び非異方性充填材の少なくともいずれかの種類を、他の単位層14におけるこれらの種類と異ならせてもよい。
さらに、複数の単位層14は、すべての単位層14が鱗片状充填材12を含有する必要はなく、一部の単位層14が鱗片状充填材12を含有してもよく、例えば、複数の単位層14のうち少なくとも1つの単位層14が鱗片状充填材12を含有する態様であってもよい。すなわち、上記各実施形態では、熱伝導性シート20の全ての領域において、第1及び第2の方向の一方向に沿う鱗片状充填材12が含有される必要はなく、熱伝導性シート20の一部において第1及び第2の方向のいずれかに沿う鱗片状充填材12が含有されるとよい。
同様に、複数の単位層14のうち一部が、繊維状充填材13を含有し、その他が繊維状充填材13を含有しなくてもよい。また、複数の単位層14のうち一部が、非異方性充填材を含有し、その他が非異方性充填材を含有しなくてもよい。
例えば、一部の単位層14のシリコーン樹脂の種類又は量、熱伝導性充填材の種類又は量の少なくとも一部を、他の単位層14と異ならせることで、一部の単位層14の硬さ(タイプE硬さまたはタイプOO硬さ)を他の単位層14の硬さと異ならせてもよい。
[液状組成物(混合物)の粘度の測定]
各例の液状組成物の粘度を、粘度計(BROOKFIELD製の回転粘度計DV-E)で、スピンドルSC4-14の回転子を用い、回転速度1rpm、測定温度25℃で測定した。結果を表1に示す。
作製した熱伝導性シートの厚み方向(第1の方向)の熱伝導率をASTM D5470-06に準拠した方法で測定した。また第2の方向及び第3の方向の熱伝導率もASTM D5470-06に準拠した方法で測定した。結果を表1に示す。
なお、第2の方向の熱伝導率は、後述の各例の積層ブロックを、第2の方向が厚さ方向となるように切断した試験片(厚さ2mm)を測定した熱伝導率であり、第3の方向の熱伝導率は、各例の1次シート(厚さ2mm)を測定した熱伝導率である。
なお、第2の方向の熱特性のレベルを百分率で示した。具体的には、第1の方向と同等を“100%”、第3の方向と同等を“0%”となるように下記式で計算した。
第2の方向の熱特性レベル(%)=(λ2-λ3)/(λ1-λ3)×100
λ1:第1の方向の熱伝導率
λ2:第2の方向の熱伝導率
λ3:第3の方向の熱伝導率
タイプE硬さは、各実施例、比較例で得られた熱伝導性シート及び1次シートを5枚重ねて10mmの試験片として、ASTM D2240-05の規定に従って測定した。結果を表1に示す。
[圧縮率]
圧縮率は、各実施例、比較例で得られた熱伝導性シートを、外形が10mm×10mmのサンプルに調製して、明細書記載のとおりに0.276MPa(=40psi)で圧縮したときの圧縮率を測定した。結果を表1に示す。
硬化性シリコーン組成物として、アルケニル基含有オルガノポリシロキサン(主剤)とハイドロジェンオルガノポリシロキサン(硬化剤)(合計で100質量部、体積充填率38体積%)と、鱗片状充填材として窒化ホウ素粉末(平均長軸長40μm、第1のアスペクト比=1、第2のアスペクト比=4~8、熱伝導率100W/(m・K))180質量部(体積充填率30体積%)と、非異方性充填材としての酸化アルミニウム(球状、平均粒径3μm、アスペクト比1.0)340質量部(体積充填率32体積%)とを混合して、スラリー状の液状組成物(混合物)を得た。液状組成物の25℃における粘度は480Pa・sであった。
熱伝導シートにおいて、鱗片状充填材は、長軸方向が厚さ方向(第1の方向)に沿って、横軸方向がシート面方向における第1の方向に垂直な方向(第2の方向)に沿って配向していた。なお、以下の各実施例でも同様であった。
液状組成物の調製において、鱗片状充填材として鱗片状黒鉛粉末(平均長軸長130μm、第1のアスペクト比=2、第2のアスペクト比=6~13、熱伝導率400W/(m・K))を使用し、各充填材の配合部数を表1に記載のとおりに変更した点を除いて実施例1と同様に実施した。
なお、シリコーン樹脂の体積充填率が38体積%、鱗片状充填材の体積充填率が23体積%、非異方性充填材の体積充填率39体積%、液状組成物の25℃における粘度は600Pa・sであった。
液状組成物の調製において、鱗片状充填材として鱗片状黒鉛粉末(平均長軸長80μm、第1のアスペクト比=1.85、第2のアスペクト比=4~8、熱伝導率400W/(m・K))を使用し、各充填材の配合部数を表1に記載のとおりに変更した点を除いて実施例1と同様に実施した。シリコーン樹脂、及び各充填材の体積充填率は実施例2と同じであり、液状組成物の25℃における粘度は750Pa・sであった。
液状組成物の調製において、鱗片状充填材として鱗片状黒鉛粉末(平均長軸長40μm、第1のアスペクト比=1.7、第2のアスペクト比=3~6、熱伝導率400W/(m・K))を使用し、各充填材の配合部数を表1に記載のとおりに変更した点を除いて実施例1と同様に実施した。シリコーン樹脂、及び各充填材の体積充填率は実施例2と同じであり、液状組成物の25℃における粘度は940Pa・sであった。
液状組成物の調製において、さらに繊維状充填材として黒鉛化炭素繊維(平均繊維長100μm、アスペクト比10、熱伝導率500W/(m・K))を配合し、かつ各充填材の配合部数を表1に記載のとおりに変更した点を除いて実施例4と同様に実施した。なお、繊維状充填材は繊維軸方向が厚さ方向(第1の方向)に沿うように配向しており、以下の実施例、比較例においても同様であった。
なお、シリコーン樹脂の体積充填率が38体積%、鱗片状充填材の体積充填率が9体積%、繊維状充填材の体積充填率14体積%、非異方性充填材の体積充填率39体積%、液状組成物の25℃における粘度は750Pa・sであった。
液状組成物の調製において、各充填材の配合部数を表1に記載のとおりに変更した点を除いて実施例5と同様に実施した。なお、シリコーン樹脂の体積充填率が38体積%、鱗片状充填材の体積充填率が14体積%、繊維状充填材の体積充填率9体積%、非異方性充填材の体積充填率39体積%、液状組成物の25℃における粘度は540Pa・sであった。
液状組成物の調製において、各充填材の配合部数を表1に記載のとおりに変更した点を除いて実施例4と同様に実施した。なお、シリコーン樹脂の体積充填率が38体積%、鱗片状充填材の体積充填率が22体積%、非異方性充填材の体積充填率40体積%、液状組成物の25℃における粘度は960Pa・sであった。
液状組成物の調製において、鱗片状充填材を使用せず、各充填材の配合部数を表1に記載のとおりに変更した点を除いて実施例1と同様に実施した。なお、シリコーン樹脂の体積充填率が37体積%、繊維状充填材の体積充填率20体積%、非異方性充填材の体積充填率43体積%、液状組成物の25℃における粘度は360Pa・sであった。
液状組成物の調製において、鱗片状充填材を使用せず、各充填材の配合部数を表1に記載のとおりに変更した点を除いて実施例1と同様に実施した。なお、シリコーン樹脂の体積充填率が38体積%、繊維状充填材の体積充填率22体積%、非異方性充填材の体積充填率40体積%、液状組成物の25℃における粘度は450Pa・sであった。
それに対して、各比較例の熱伝導性シートでは、長軸方向Yを第1の方向に、横軸方向Xを第2の方向に沿って配向させた鱗片状充填材を含有させなかったので、厚さ方向及び面方向に沿う一方向の両方の熱伝導率が向上せず、そのため、厚さ方向及び面方向に沿う一方向の両方の熱抵抗値を低くできなった。
10A 一方の面
10B 他方の面
11 高分子マトリクス
12 鱗片状充填材
13 繊維状充填材
14 単位層
17 1次シート
18 積層ブロック
19 刃物
Claims (12)
- 高分子マトリクス中に鱗片状充填材を含む熱伝導性シートであって、
前記鱗片状充填材が、鱗片面の長軸方向が、前記熱伝導性シートの厚さ方向である第1の方向及び前記第1の方向に垂直である第2の方向のいずれか一方に沿い、かつ前記鱗片面において長軸方向に垂直となる横軸方向が、前記第1の方向及び前記第2の方向の他方に沿うように配向する、熱伝導性シート。 - 前記鱗片状充填材は、前記長軸方向が前記第1の方向に沿い、かつ前記横軸方向が前記第2の方向に沿うように配向する請求項1に記載の熱伝導性シート。
- 前記鱗片状充填材は、前記横軸方向が前記第1の方向に沿い、かつ前記長軸方向が前記第2の方向に沿うように配向する、請求項1に記載の熱伝導性シート。
- 前記鱗片状充填材の前記横軸方向の長さに対する、前記長軸方向の長さの比(長軸方向の長さ/横軸方向の長さ)で表される第1のアスペクト比が1.5以上である請求項1~3のいずれか1項に記載の熱伝導性シート。
- 前記鱗片状充填材の平均粒径が20μm以上である請求項1~4のいずれか1項に記載の熱伝導性シート。
- 前記鱗片状充填材が、鱗片状黒鉛粉末を含む請求項1~5のいずれか1項に記載の熱伝導性シート。
- 前記鱗片状充填材が、鱗片状窒化ホウ素粉末を含む請求項1~6のいずれか1項に記載の熱伝導性シート。
- 前記高分子マトリクス中にさらに繊維状充填材を含む請求項1~7のいずれか1項に記載の熱伝導性シート。
- 前記繊維状充填材が、炭素繊維である請求項8に記載の熱伝導性シート。
- 複数の単位層を有し、かつ前記複数の単位層のうち、少なくとも1つが前記鱗片状充填材を含み、
複数の単位層が、前記第1及び第2の方向に垂直な第3の方向に沿って積層される請求項1~9のいずれか1項に記載の熱伝導性シート。 - 前記高分子マトリクス中にさらに非異方性充填材を含有する請求項1~10のいずれか1項に記載の熱伝導性シート。
- 請求項1~11のいずれか1項に記載の熱伝導性シートの製造方法であって、
前記高分子マトリクスの前駆体である樹脂と、前記鱗片状充填材とを含む混合物を調製する工程と、
前記混合物を流動配向処理して、前記鱗片状充填材を配向させつつ、1次シートを得る工程と、
前記1次シートを積層して積層ブロックを得る工程と、
前記積層ブロックを積層方向に沿って切断する工程と
を備える熱伝導性シートの製造方法。
Priority Applications (7)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE112020005404.7T DE112020005404T5 (de) | 2019-11-01 | 2020-10-26 | Wärmeleitende folie und herstellungsverfahren für dieselbe |
JP2021507107A JP6892725B1 (ja) | 2019-11-01 | 2020-10-26 | 熱伝導性シート及びその製造方法 |
KR1020227013284A KR102452165B1 (ko) | 2019-11-01 | 2020-10-26 | 열전도성 시트 및 그 제조 방법 |
US17/770,539 US11618247B2 (en) | 2019-11-01 | 2020-10-26 | Thermally conductive sheet and production method for same |
CN202080072965.5A CN114555714B (zh) | 2019-11-01 | 2020-10-26 | 导热片及其制造方法 |
CN202310426568.9A CN116355425A (zh) | 2019-11-01 | 2020-10-26 | 导热片及其制造方法 |
KR1020227030763A KR20220129092A (ko) | 2019-11-01 | 2020-10-26 | 열전도성 시트 및 그 제조 방법 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2019200095 | 2019-11-01 | ||
JP2019-200095 | 2019-11-01 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2021085383A1 true WO2021085383A1 (ja) | 2021-05-06 |
Family
ID=75715943
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2020/040121 WO2021085383A1 (ja) | 2019-11-01 | 2020-10-26 | 熱伝導性シート及びその製造方法 |
Country Status (7)
Country | Link |
---|---|
US (1) | US11618247B2 (ja) |
JP (2) | JP6892725B1 (ja) |
KR (2) | KR102452165B1 (ja) |
CN (2) | CN114555714B (ja) |
DE (1) | DE112020005404T5 (ja) |
TW (1) | TW202124585A (ja) |
WO (1) | WO2021085383A1 (ja) |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR102646809B1 (ko) | 2018-06-22 | 2024-03-13 | 세키수이 폴리머텍 가부시키가이샤 | 열전도성 시트 |
CN112715059A (zh) * | 2018-09-26 | 2021-04-27 | 积水保力马科技株式会社 | 导热片 |
US11742258B2 (en) * | 2020-05-15 | 2023-08-29 | Dexerials Corporation | Thermally conductive sheet and method for manufacturing thermally conductive sheet |
JP6980868B1 (ja) * | 2020-08-25 | 2021-12-15 | デクセリアルズ株式会社 | 熱伝導性シート及び熱伝導性シートの製造方法 |
JP6999003B1 (ja) | 2020-09-09 | 2022-01-18 | デクセリアルズ株式会社 | 熱伝導性シート及び熱伝導性シートの製造方法 |
US11615999B1 (en) * | 2022-07-22 | 2023-03-28 | GuangDong Suqun New Material Co., Ltd | Oriented heat conducting sheet and preparation method thereof, and semiconductor heat dissipating device |
WO2024018635A1 (ja) * | 2022-07-22 | 2024-01-25 | 株式会社レゾナック | 熱伝導シート、放熱装置及び熱伝導シートの製造方法 |
WO2024090364A1 (ja) * | 2022-10-28 | 2024-05-02 | 帝人株式会社 | 積層体及びその製造方法 |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009094110A (ja) * | 2007-10-03 | 2009-04-30 | Denki Kagaku Kogyo Kk | 放熱部材、及びそのシート、およびその製造方法 |
JP2014148094A (ja) * | 2013-02-01 | 2014-08-21 | Sumitomo Bakelite Co Ltd | 熱伝導シートおよび熱伝導シートの製造方法 |
WO2017179318A1 (ja) * | 2016-04-11 | 2017-10-19 | ポリマテック・ジャパン株式会社 | 熱伝導性シート |
JP2019026884A (ja) * | 2017-07-28 | 2019-02-21 | 昭和電工株式会社 | 金属−炭素粒子複合材 |
WO2019160004A1 (ja) * | 2018-02-14 | 2019-08-22 | 積水ポリマテック株式会社 | 熱伝導性シート |
Family Cites Families (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH09283955A (ja) | 1996-04-10 | 1997-10-31 | Matsushita Electric Works Ltd | 放熱シート |
JP2001110961A (ja) | 1999-10-08 | 2001-04-20 | Fujikura Rubber Ltd | 放熱シート |
JP2002026202A (ja) | 2000-06-29 | 2002-01-25 | Three M Innovative Properties Co | 熱伝導性シート及びその製造方法 |
JP2002121393A (ja) | 2000-10-12 | 2002-04-23 | Sekisui Chem Co Ltd | 熱伝導性樹脂組成物及び熱伝導性シート |
JP2004051852A (ja) * | 2002-07-22 | 2004-02-19 | Polymatech Co Ltd | 熱伝導性高分子成形体及びその製造方法 |
JP4629475B2 (ja) | 2005-03-30 | 2011-02-09 | 株式会社カネカ | 放熱シート用組成物およびそれを硬化させてなる放熱シート |
JP2007012913A (ja) | 2005-06-30 | 2007-01-18 | Polymatech Co Ltd | 放熱シート及び放熱構造 |
JP5381102B2 (ja) | 2006-11-01 | 2014-01-08 | 日立化成株式会社 | 熱伝導シート、その製造方法及び熱伝導シートを用いた放熱装置 |
KR20110085991A (ko) | 2008-10-21 | 2011-07-27 | 히다치 가세고교 가부시끼가이샤 | 열전도 시트, 그 제조방법 및 이것을 이용한 방열 장치 |
JP2011184663A (ja) | 2010-03-11 | 2011-09-22 | Hitachi Chem Co Ltd | 熱伝導シート、その製造方法及びこれを用いた放熱装置 |
JP5454300B2 (ja) | 2010-03-30 | 2014-03-26 | 日立化成株式会社 | 熱伝導シート、その製造方法及びこれを用いた放熱装置 |
JP5443657B2 (ja) | 2011-12-27 | 2014-03-19 | パナソニック株式会社 | シートの異方性熱伝導組成物の成形品 |
JP2014014809A (ja) | 2012-07-11 | 2014-01-30 | Fujifilm Corp | 二酸化炭素分離用複合体の製造方法、二酸化炭素分離用複合体、二酸化炭素分離モジュール、二酸化炭素分離装置、及び二酸化炭素分離システム |
JP5953160B2 (ja) | 2012-07-27 | 2016-07-20 | ポリマテック・ジャパン株式会社 | 熱伝導性成形体の製造方法 |
JP6094119B2 (ja) * | 2012-09-26 | 2017-03-15 | 住友ベークライト株式会社 | 熱伝導シートの製造方法 |
JP5798210B2 (ja) | 2013-07-10 | 2015-10-21 | デクセリアルズ株式会社 | 熱伝導性シート |
JP6071935B2 (ja) | 2013-09-06 | 2017-02-01 | バンドー化学株式会社 | 樹脂成形品の製造方法 |
CN109729739B (zh) | 2016-08-08 | 2023-04-18 | 积水化学工业株式会社 | 热传导片和其制造方法 |
JP7087372B2 (ja) | 2017-12-19 | 2022-06-21 | 日本ゼオン株式会社 | 熱伝導シート及びその製造方法 |
JPWO2021065522A1 (ja) * | 2019-09-30 | 2021-04-08 |
-
2020
- 2020-10-26 CN CN202080072965.5A patent/CN114555714B/zh active Active
- 2020-10-26 DE DE112020005404.7T patent/DE112020005404T5/de active Pending
- 2020-10-26 WO PCT/JP2020/040121 patent/WO2021085383A1/ja active Application Filing
- 2020-10-26 CN CN202310426568.9A patent/CN116355425A/zh active Pending
- 2020-10-26 KR KR1020227013284A patent/KR102452165B1/ko active IP Right Grant
- 2020-10-26 JP JP2021507107A patent/JP6892725B1/ja active Active
- 2020-10-26 KR KR1020227030763A patent/KR20220129092A/ko unknown
- 2020-10-26 US US17/770,539 patent/US11618247B2/en active Active
- 2020-10-28 TW TW109137460A patent/TW202124585A/zh unknown
-
2021
- 2021-05-21 JP JP2021086144A patent/JP2021145134A/ja active Pending
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009094110A (ja) * | 2007-10-03 | 2009-04-30 | Denki Kagaku Kogyo Kk | 放熱部材、及びそのシート、およびその製造方法 |
JP2014148094A (ja) * | 2013-02-01 | 2014-08-21 | Sumitomo Bakelite Co Ltd | 熱伝導シートおよび熱伝導シートの製造方法 |
WO2017179318A1 (ja) * | 2016-04-11 | 2017-10-19 | ポリマテック・ジャパン株式会社 | 熱伝導性シート |
JP2019026884A (ja) * | 2017-07-28 | 2019-02-21 | 昭和電工株式会社 | 金属−炭素粒子複合材 |
WO2019160004A1 (ja) * | 2018-02-14 | 2019-08-22 | 積水ポリマテック株式会社 | 熱伝導性シート |
Also Published As
Publication number | Publication date |
---|---|
CN114555714A (zh) | 2022-05-27 |
JP6892725B1 (ja) | 2021-06-23 |
CN114555714B (zh) | 2023-05-09 |
US20220347996A1 (en) | 2022-11-03 |
JPWO2021085383A1 (ja) | 2021-11-25 |
JP2021145134A (ja) | 2021-09-24 |
KR20220129092A (ko) | 2022-09-22 |
KR20220054713A (ko) | 2022-05-03 |
US11618247B2 (en) | 2023-04-04 |
DE112020005404T5 (de) | 2022-08-18 |
KR102452165B1 (ko) | 2022-10-11 |
TW202124585A (zh) | 2021-07-01 |
CN116355425A (zh) | 2023-06-30 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP6844806B2 (ja) | 熱伝導性シート及びその製造方法 | |
JP6892725B1 (ja) | 熱伝導性シート及びその製造方法 | |
WO2021065522A1 (ja) | 熱伝導性シート及びその製造方法 | |
JP7221487B2 (ja) | 熱伝導性シート | |
WO2020050334A1 (ja) | 熱伝導性シート | |
WO2019244890A1 (ja) | 熱伝導性シート | |
JP6978148B1 (ja) | 熱伝導性シート及びその製造方法 | |
WO2022137762A1 (ja) | 熱伝導性シート、その装着方法及び製造方法 | |
JP7473103B2 (ja) | 熱伝導性シート及びその製造方法 | |
WO2022210420A1 (ja) | 熱伝導性部材の製造方法、及びディスペンサ装置 | |
WO2022070568A1 (ja) | 熱伝導性シート、その装着方法及び製造方法 | |
WO2022210419A1 (ja) | 熱伝導性シートの製造方法 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
ENP | Entry into the national phase |
Ref document number: 2021507107 Country of ref document: JP Kind code of ref document: A |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 20881202 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 20227013284 Country of ref document: KR Kind code of ref document: A |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 20881202 Country of ref document: EP Kind code of ref document: A1 |