WO2025065334A1 - Composition de silicone thermoconductrice - Google Patents

Composition de silicone thermoconductrice Download PDF

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Publication number
WO2025065334A1
WO2025065334A1 PCT/CN2023/122025 CN2023122025W WO2025065334A1 WO 2025065334 A1 WO2025065334 A1 WO 2025065334A1 CN 2023122025 W CN2023122025 W CN 2023122025W WO 2025065334 A1 WO2025065334 A1 WO 2025065334A1
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thermally conductive
less
weight
conductive composition
percent
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Inventor
Yan Zheng
Dorab E. Bhagwagar
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Dow Silicones Corp
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Dow Silicones Corp
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Priority to PCT/CN2023/122025 priority Critical patent/WO2025065334A1/fr
Priority to TW113133819A priority patent/TW202513716A/zh
Publication of WO2025065334A1 publication Critical patent/WO2025065334A1/fr
Anticipated expiration legal-status Critical
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    • 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
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/04—Polysiloxanes
    • C08G77/12—Polysiloxanes containing silicon bound to hydrogen
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
    • C08G77/04—Polysiloxanes
    • C08G77/20—Polysiloxanes containing silicon bound to unsaturated aliphatic groups
    • 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
    • C08K3/08—Metals
    • C08K2003/0812—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
    • C08K3/18—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
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/20—Oxides; Hydroxides
    • C08K3/22—Oxides; Hydroxides of metals
    • C08K2003/2296—Oxides; Hydroxides of metals of zinc
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/28—Nitrogen-containing compounds
    • C08K2003/282—Binary compounds of nitrogen with aluminium

Definitions

  • the present invention relates to a thermally conductive silicone composition that contains thermally conductive fillers including a novel combination of at least three different thermally conductive particles.
  • thermally conductive compositions useful for dissipating heat generated in such devices.
  • the heat generated by the high power in the smaller devices would damage the device if not efficiently dissipated.
  • advanced integrated circuit devices like CPU in consumer devices produce large amounts of heat due to the acceleration of operating speed.
  • Thermally conductive interface materials are often used in electronics to thermally couple heat generating components and heat dissipating components.
  • a challenge with silicone grease compositions is to provide a combination of good thermal conductivity properties to efficiently transfer heat between coupled components, at the same time, being easily extrudable or dispensable so as to allow precise application of the thermally conductive material on small components.
  • a thermally conductive interface material that has an extrusion rate of at least 40 grams per minute as measured using the Extrusion Rate Test defined herein below and that cures to a material that has a thermal conductivity (TC) of at least 6.0 Watts per meter*Kelvin (W/m*K) as measured using a hot disk according to ISO 22007-2 and a thermal resistance (TR) of no more than 0.12 degree Celsius square centimeter per Watt (°C*cm 2 /W) as determined by ASTM D-5470.
  • Aluminum (Al) filler particles have a high thermal conductivity of 200 W/m*K and can be used to afford the silicone composition with the above described high TC in applications where electrical insulation properties are not needed. However, due to the electrical conductivity of aluminum, addition of greater than 30%by weight of aluminum particles based on the silicone composition weight usually compromises the electrical insulating properties of the silicone composition and the cured product, which make them not suitable for heat transfer involving high-voltage applications.
  • a thermally conductive grease compositions is usually applied between an electronic component and a member such as heat sink for efficiently releasing the heat from the electronic component.
  • Incumbent silicone grease compositions usually comprise silicone fluids loaded with alumina (Al 2 O 3 ) filler.
  • Al 2 O 3 alumina
  • the average particle size of Al 2 O 3 filler needs to be in an appropriate range, enabling the composition to be compressed to fill thin gaps and meet the thermal resistance requirement ( ⁇ 0.12 °C*cm 2 /W) .
  • the present invention provides a thermally conductive composition that has an extrusion rate (ER) of 40 grams per minute (g/min) or more as measured using the Extrusion Rate Test defined herein below and that cures to a material that has a thermal resistance (TR) of no greater than 0.12 degree Celsius square centimeter per Watt (°C*cm 2 /W) according to ASTM D-5470 and a thermal conductivity (TC) of at least 6.0 Watts per meter*Kelvin (W/m*K) using a hot disk according to ISO 22007-2.
  • the composition of the present invention is particularly suitable for use as a thermally conductive silicone grease that can achieve a Bond Line Thickness (BLT) of 80 ⁇ m or less, while still meeting the TR and TC requirements.
  • BLT Bond Line Thickness
  • composition can be prepared from a polysiloxane composition (also as “thermally conductive composition” ) that comprises a novel combination of specific amounts of at least three thermally conductive fillers different in types and/or particle size.
  • the present invention is a thermally conductive composition comprising, based on the weight of the thermally conductive composition,
  • R a is independently in each occurrence an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 10 carbon atoms
  • R’ is independently in each occurrence an alkenyl group, subscript a ⁇ 0, subscript b > 0, subscript c is 0 or 1, subscript d is 0 or 1, and (a+c+d) ⁇ 2;
  • the combined concentration of the aluminum oxide particles (C1-a) and the aluminum nitride particles (C1-b) is in a range of from 45 to 65 weight-percent;
  • C3 from 10 to 25 weight-percent of a third thermally conductive filler having a D50 in a range of 0.1 to 0.6 micrometer, wherein the third thermally conductive filler is selected from the group consisting of zinc oxide particles, aluminum oxide particles, and mixtures thereof; and
  • the present invention is a process for using the thermally conductive composition of the first aspect.
  • the process comprises the steps of: a) applying the thermally conductive composition on an electronic component, and b) curing the thermally conductive composition by heat.
  • the present invention is an electronic article comprising the thermally conductive composition of the first aspect between and in contact with two components of the electronic article, wherein the thermally conductive composition is in either a cured or non-cured form.
  • Test methods refer to the most recent test method as of the priority date of this document when a date is not indicated with the test method number. References to test methods contain both a reference to the testing society and the test method number. The following test method abbreviations and identifiers apply herein: ASTM refers to ASTM International methods and ISO refers to International Organization for Standards.
  • Spherical shaped particles refer to particles that have an aspect ratio of 1.0 +/-0.2.
  • the aspect ratio of a particle is determined using scanning electron microscope (SEM) imaging and by taking the average ratio of the longest dimension (major axis) and shortest dimension (minor axis) of at least ten particles.
  • “Roundish” refers to a shape in which the corners of the particles are small, and the entire particles are single grain with less crystal edges.
  • the roundish particles have an aspect ratio other than 1.0 +/-0.2, may be elliptical, or the like, but does not include a sphere.
  • Polyhedron refers to a shape surrounded by a plurality of planes such as a hexahedron, an octahedron, and a dodecahedron. Each plane does not necessarily have the same shape.
  • “Irregular” shaped particles refer to a shape that does not have a fixed shape such as “spherical” , “roundish” , or “polyhedron” .
  • the irregular particles have an aspect ratio other than 1.0 +/-0.2 and have sharp, uneven, different shape corners evident by SEM imaging.
  • Particle size of thermally conductive fillers refers to the volume-weighted median value of particle diameter distribution (D50) .
  • D50 can be measured using a laser diffraction particle size analyzer such as a Mastersizer TM (trademark of Malvern Instruments Limited) 3000 laser diffraction particle size analyzer from Malvern Instruments.
  • Viscosity of a polysiloxane is determined according to ASTM D445-21 at 25 degrees Celsius (°C) unless otherwise stated.
  • a glass capillary Cannon-Fenske type viscometer can be used to determine the viscosity.
  • the thermally conductive composition of the present invention is a curable composition, that is, can undergo a crosslinking reaction ( “curing” ) .
  • the crosslinking reaction is a hydrosilylation reaction between alkenyl-functional polyorganosiloxane components and silyl-hydride (SiH) functional polysiloxane crosslinker.
  • the thermally conductive composition of the present invention comprises an alkenyl-functional polyorganosiloxane that has two or more alkenyl groups per molecule (component (A) ) .
  • Alkenyl means a branched or unbranched, monovalent hydrocarbon group having one or more carbon-carbon double bonds.
  • the alkenyl groups can be terminal, pendant, or a combination of both terminal and pendant.
  • Terminal” groups are on end siloxane groups of a molecule.
  • End siloxane groups are attached to only one other siloxane group.
  • “Pendant” groups are on interior siloxane group -siloxane groups bound to at least two other siloxane groups of the molecule.
  • Siloxane group is a group containing SiO that is bound to another Si through the oxygen of the SiO.
  • the alkenyl-functional polydiorganosiloxane has an average of one or more terminally alkenyl groups per molecule.
  • the alkenyl-functional polyorganosiloxane has a viscosity in a range of 25 to 500 millipascal*seconds (mPa*s) . If the viscosity is too low, then separation of polymer matrix and fillers tends to occur, therefore, hurting physical properties of the composition. If the viscosity is too high, it may be difficult to incorporate sufficient fillers so as to achieve the desired TC and ER properties.
  • the alkenyl-functional polyorganosiloxane (A) useful in the present invention has an average chemical structure (I) : R a (3-c) R’ c SiO- (R’R a SiO) a - (R a 2 SiO) b -SiR’ d R a (3-d) (I)
  • R a is independently in each occurrence an alkyl group of 1 to 6 carbon atoms or an aryl group of 6 to 10 carbon atoms
  • R’ is independently in each occurrence an alkenyl group
  • subscript a is zero or more ( ⁇ 0)
  • subscript b is greater than zero (>0)
  • subscript c is 0 or 1
  • subscript d is 0 or 1
  • (a+c+d) is 2 or more ( ⁇ 2) .
  • Suitable aryl groups for R a are exemplified by phenyl, tolyl, xylyl, naphthyl, benzyl, and dimethyl phenyl.
  • Each R a may be the same or different.
  • Each R a can be an alkyl group. Desirably, each R a is independently methyl, ethyl, or propyl, and more desirably, each R a is methyl.
  • the alkenyl group for R’ typically has from 2 to 8 carbon atoms, from 2 to 6 carbon atoms or from 2 to 4 carbon atoms.
  • Suitable alkenyl groups may include vinyl, allyl, butenyl, and hexenyl. Particularly suitable alkenyl groups for R’ vinyl, allyl, butenyl, and hexenyl.
  • R’ groups may be the same or different. Desirably, each R’ is selected from vinyl or hexenyl. More desirably, each R’ is vinyl.
  • subscript a is zero, subscript c is 1, subscript d is 1, and each R a is methyl.
  • Subscript a is the average number of (R’R a SiO) groups per molecule.
  • Subscript b is the average number of (R a 2 SiO) groups per molecule.
  • a quantity (a+b) is 20 to 600, and can be 25 or more, 30 or more, 40 or more, 50 or more, 60 or more, 70 or more, 80 or more, 90 or more, 100 or more, 120 or more, 140 or more, 160 or more, even 180 or more while at the same time is typically 600 or less, and can be 560 or less, 500 or less, 400 or less, 350 or less, 200 or less, 180 or less, 160 or less, 140 or less, 120 or less, 100 or less, 80 or less, 60 or less, even 40 or less, desirably, 25 to 60.
  • a quantity (a+c+d) is 2 or more, even 3 or more while at the same time is typically 30 or less, and can be 20 or less, 10 or less, or even 3 or less.
  • alkenyl-functional polyorganosiloxanes include i) vinyldimethylsiloxy-terminated polydimethylsiloxane, ii) dimethylvinylsiloxy-terminated poly (dimethylsiloxane/methylvinylsiloxane) , iii) dimethylvinylsiloxy-terminated polymethylvinylsiloxane, iv) trimethylsiloxy-terminated poly (dimethylsiloxane/methylvinylsiloxane) , v) trimethylsiloxy-terminated polymethylvinylsiloxane, vi) dimethylvinylsiloxy-terminated poly (dimethylsiloxane/methylvinylsiloxane) , or mixtures thereof.
  • the alkenyl-functional polyorganosiloxane comprises, or consists of, one or any combination of more than one vinyldimethylsiloxy-terminated polydimethylpolysiloxane (A1) of an average chemical structure (II) : Vi(CH 3 ) 2 SiO- ( (CH 3 ) 2 SiO) b -Si (CH 3 ) 2 Vi (II)
  • Vi represents vinyl
  • subscript b is the average number of ( (CH 3 ) 2 SiO) groups per molecule and has a value of 20 to 600, and can be 20 or more, 25 or more, 30 or more, 40 or more, 45 or more, 50 or more, 60 or more, 70 or more, 80 or more, 90 or more, 100 or more, 120 or more, 140 or more, 160 or more, even 180 or more while at the same time typically have a value of 600 or less, and can be 560 or less, 500 or less, 400 or less, 350 or less, 200 or less, 180 or less, 160 or less, 140 or less, 120 or less, 100 or less, 80 or less, 60 or less, 45 or more, even 40 or less, desirably from 20 to 200.
  • the alkenyl-functional polyorganosiloxane can be a vinyldimethylsiloxy terminated polydimethylsiloxane having a viscosity of 60 mPa*s and containing 1.55 weight-percent (wt%) vinyl groups relative to molecular weight such as that available from Gelest under the name HMS-501.
  • the concentration of component (A) the alkenyl-functional polyorganosiloxane may be from 1.0 to 4.0 wt%, and can be 1.0 wt%or more, 1.5 wt%or more, 1.8 wt%or more, 2.0 wt%or more, 2.4 wt%or more, 2.5 wt%or more, 2.6 wt%or more, 2.7 wt%or more, 2.8 wt%or more, 2.9 wt%or more, even 3.0 wt%or more while at the same time is generally 4.0 wt%or less, and can be 3.8 wt%or less, 3.5 wt%or less, 3.3 wt%or less, 3.0 wt%or less, 2.9 wt%or less, 2.8 wt%or less, 2.7 wt%or less, or even 2.6 wt%or less, desirably, from 1.8 to 2.8 wt%, based on the weight of the thermally conductive
  • the thermally conductive composition of the present invention comprises a silyl-hydride (SiH) functional polysiloxane crosslinker (component (B) , also referred to as “SiH crosslinker” ) .
  • the SiH functional polysiloxane crosslinker contains at least two silyl-hydride groups (i.e., containing at least two silicon-bonded hydrogen atoms) , or even 3 or more, per molecule.
  • the SiH groups can be pendant, terminal or a combination of both pendant and terminal.
  • the SiH functional polysiloxane crosslinker can have an average chemical structure (III) : R bb (3-h) H h SiO- (HR bb SiO) e - (R bb 2 SiO) f -SiH h′ R bb (3-h′) (III)
  • R bb is independently in each occurrence selected from an alkyl group having from 1 to 6 carbon atoms and phenyl; subscripts h and h′ each are independently in each occurrence selected from a value in a range of zero to 3 provided that the combination of e, h, and h′ is at least 2; subscript e is zero to 30;and subscript f is 5 to 200.
  • the R bb group can have one carbon or more, 2 carbons or more, 3 carbons or more, 4 carbons or more, even 5 carbons or more while at the same time 6 carbons or fewer, 5 carbons or fewer, 4 carbons or fewer, 3 carbons or fewer, even 2 carbons or fewer.
  • the R bb group is independently in each occurrence selected from methyl and phenyl.
  • H is a hydrogen atom.
  • Subscripts h and h′ refer to the average number of terminal hydrogen atoms on either end and each are independently in each occurrence selected from a value in a range of zero to 3 provided that the combination of e, h, and h′ is at least 2. Desirably, h and h′ are independently in each occurrence 0 or more, 1 or more, even 2 or more while at the same time 3 or less, 2 or less, even 1 or less. More desirably, h and h′ have the same value. Most desirably, h and h′ are both zero.
  • Subscript e is the average number of (HR bb SiO) groups per molecule. If h and h′ are both zero then e is in a range of 2 to 30.
  • subscript e can be zero to 30 provided the combination of e, h and h′ is 2 or more.
  • subscript e is 1 or more, and can be 2 or more and can be 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, 8 or more, even 9 or more while at the same time typically is 30 or less, and can be 25 or less, 20 or less, 15 or less, 10 or less, 9 or less, 8 or less, 7 or less, 6 or less, 5 or less, 4 or less, 3 or less, even 2 or less.
  • Subscript f is the average number of (R bb 2 SiO) groups per molecule.
  • subscript f is 5 or more, 10 or more, 20 or more, 25 or more, 30 or more, 40 or more, 50 or more, and can be 75 or more, 100 or more, 125 or more, 150 or more, 175 or more, even 190 or more while at the same time is typically 200 or less, 175 or less, 150 or less, 125 or less, 100 or less, 75 or less, 50 or less, 40 or less, 30 or less, 25 or less, or even 20 or less.
  • the SiH functional polysiloxane crosslinker comprises one or more polysiloxane having chemical structures selected from (III-a) , (III-b) , or combinations thereof: H(CH 3 ) 2 SiO- [ (CH 3 ) 2 SiO) ] x -Si (CH 3 ) 2 H (III-a) (CH 3 ) 3 SiO- [ (CH 3 ) HSiO] y [ (CH 3 ) 2 SiO] z -Si (CH 3 ) 3 (III-b)
  • subscript x is 10 to 100, and can be 10 to 60, 10 to 40, or 10 to 20; subscript y is 2 to 30, and can be 2 to 20, 2 to 10, or 2 to 5; and subscript z is 3 to 100, and can be 3 to 30, 3 to 20, or 3 to 10.
  • component (B) is a combination of a SiH crosslinker of (III-a) and a SiH crosslinker of (III-b) .
  • the SiH functional polysiloxane crosslinker may have a silicon-bonded hydrogen atom ( “SiH” ) content (i.e., SiH content) of 0.01 wt%to 1.0 wt%, and can be 0.01 wt%or more, 0.05%wt%or more, 0.1 wt%or more, 0.11 wt%or more, 0.15 wt%or more, 0.20 wt%or more, 0.25 wt%or more, 0.30 wt%or more, even 0.35 wt%or more while at the same time is generally 1.0 wt%or less, and can be 0.9 wt%or less, 0.8 wt%or less, 0.7 wt%or less, 0.6 wt%or less, 0.5 wt%or less, 0.4 wt%or less, even 0.36 wt%or less, desirably, 0.1 wt%to 0.8 wt%.
  • SiH content refers to weight percentages
  • Suitable SiH functional polysiloxane crosslinkers may include, for example, trimethylsiloxy-terminated poly (dimethylsiloxane/methylhydrogensiloxane) , trimethylsiloxy-terminated polymethylhydrogensiloxane, hydrogen-terminated polydimethylsiloxane, hydrogen-terminated poly (dimethylsiloxane/methylhydrogensiloxane) , or mixtures thereof.
  • the crosslinker may be a combination of two or more crosslinkers that may differ in one or more properties selected from molecular weight, structure, siloxane units and sequence, such as a mixture of trimethyl terminated dimethyl-co-hydrogen methyl polysiloxane and a hydride terminated polydimethylsiloxane.
  • SiH crosslinkers include those having average chemical structure of Me 3 SiO (Me 2 SiO) 7 (MeHSiO) 3 SiMe 3 , Me 3 SiO (Me 2 SiO) 108 (MeHSiO) 10 SiMe 3 , Me 3 SiO (Me 2 SiO) 22 (MeHSiO) 2 SiMe 3 , HMe 2 SiO (Me 2 SiO) 25 (MeHSiO) 1 SiMe 2 H, or H (Me) 2 SiO- [Me 2 SiO) ] 14 -SiMe 2 H, where Me represents methyl, or mixtures thereof.
  • Suitable commercially available SiH crosslinkers include those available under the names HMS-071, HMS-501 and DMS-H11 all available from Gelest.
  • the SiH crosslinker can be one or a combination of both polymers selected from a group consisting of: (B-i) trimethyl terminated dimethyl-co-hydrogen methyl polysiloxane with a viscosity of 10 to 14 mPa*s at 25 °C and a SiH content of 0.36 wt%; and (B-ii) hydride terminated polydimethylsiloxane having a viscosity in a range of 7-10 mPa*s 25 °C and a SiH content of 0.16 wt%.
  • the concentration of the SiH functional polysiloxane crosslinker is sufficient to provide a molar ratio of silicon-bonded hydrogen atoms from the crosslinker to alkenyl groups (desirably, vinyl groups) in the thermally conductive composition (also as “SiH/Vi ratio” ) in a range of from 0.4: 1 to 1.5: 1, and can be 0.4: 1 or higher, 0.5: 1 or higher, 0.6: 1 or higher, 0.7: 1 or higher, 0.8: 1 or higher, even 0.9: 1 or higher while at the same time is 1.5: 1 or less, and can be 1.4: 1 or less, 1.2: 1 or less, 1: 1 or less, 0.9: 1 or less, 0.8: 1 or less, 0.7: 1 or less, or even 0.6: 1 or less.
  • the SiH/Vi ratio is 0.6: 1 to 1.2: 1.
  • the SiH/Vi ratio determines the extent of crosslinking that occurs when the thermally conductive composition cures. If the SiH/Vi ratio is too low, then the composition tends not to be sufficiently cured. If the SiH/Vi ratio is too high then the composition cures so much it may become brittle and suffer from surface cracking.
  • the thermally conductive composition of the present invention comprises thermally conductive fillers (component (C) ) .
  • Component (C) comprises, and can consist of, a combination of at least three, or even four, different thermally conductive fillers, i.e., (C1) , (C2) , and (C3) , and optionally (C4) , described below.
  • the thermally conductive fillers (C) comprise the first thermally conductive filler (C1) that comprises (C1-a) aluminum oxide particles having a D50 in a range of 10 to 40 ⁇ m, and optionally (C1-b) aluminum nitrite particles having a D50 in a range of 10 to 40 ⁇ m.
  • the aluminum oxide particles (C1-a) and the aluminum nitrite particles (C1-b) may each independently have a D50 particle size of 10 ⁇ m to 40 ⁇ m, and can have a D50 of 10 ⁇ m or more, 12 ⁇ m or more, 15 ⁇ m or more, 20 ⁇ m or more, 25 ⁇ m or more, 30 ⁇ m or more, even 35 ⁇ m or more while at the same time have a D50 particle size of 40 ⁇ m or less, and can have a D50 of 38 ⁇ m or less, 35 ⁇ m or less, 32 ⁇ m or less, 30 ⁇ m or less, 28 ⁇ m or less, 25 ⁇ m or less, 22 ⁇ m or less, 20 ⁇ m or less, 18 ⁇ m or less, or even 15 ⁇ m or less.
  • the aluminum oxide particles (C1-a) have a D50 in a range of 15 to 35 ⁇ m, and more desirably, 20 to 35 ⁇ m.
  • the aluminum nitride particles (C1-b) have a D50 in a range of 10 to 30 ⁇ m, more desirably, 10 to 20 ⁇ m.
  • the concentration of the aluminum oxide particles (C1-a) is from 15 to 65 wt%, and can be 15 wt%or more, 20 wt%or more, 25 wt%or more, 30 wt%or more, 35 wt%or more, 40 wt%or more, 45 wt%or more, 50 wt%or more, 55 wt%or more, even 58 wt%or more while at the same time is 65 wt%or less, and can be 62 wt%or less, 60 wt%or less, 58 wt%or less, 55 wt%or less, 52 wt%or less, 50 wt%or less, 45 wt%or less, 40 wt%or less, 35 wt%or less, 30 wt%or less, or even 28 wt%or less, desirably, 25 wt%to 60 wt%, more desirably, 40 wt%to 60 wt%, based on
  • the concentration of aluminum nitride particles (C1-b) is in a range of from zero to 40 wt%, and can be 5 wt%or more, 15 wt%or more, even 24 wt%or more while at the same time is 40 wt%or less, and can be 30 wt%or less, 27 wt%or less, 20 wt%or less, 18 wt%or less, or even 10 wt%or less, desirably, zero to 30 wt%or 20 wt%to 30 wt%, based on the weight of the thermally conductive composition.
  • the combined concentration of the aluminum oxide particles (C1-a) and the aluminum nitride particles (C1-b) is from 45 to 65 wt%, and can be 46 wt%or more, 48 wt%or more, 50 wt%or more, 51 wt%or more, 52 wt%or more, 53 wt%or more, 54 wt%or more, 55 wt%or more, 56 wt%or more, 57 wt%or more, even 58%or more while at the same time is 65 w%or less, and can be 64 wt%or less, 63 wt%or less, 62 wt%or less, 61 wt%or less, 60 wt%or less, 59 wt%or less, or even 58 wt%, based on the total weight of the thermally conductive composition.
  • the first thermally conductive filler (C1) can consist of the aluminum oxide particles (C1-a) .
  • the thermally conductive filler (C1) can be a blend of from 25 to 45 wt%of the aluminum oxide particles (C1-a) and from 15 to 30 wt%of the aluminum nitride particles (C1-b) .
  • the first thermally conductive filler (C1) may comprise irregular, spherical, roundish, or polyhedron particles, or combinations of two or more thermally conductive fillers different in type, shape or particle size as long as each having a D50 within 10 to 40 ⁇ m.
  • the first thermally conductive filler (C1) can be roundish, spherical, irregular, and combinations thereof.
  • the first thermally conductive filler (C1) comprises roundish or spherical aluminum oxide particles.
  • the second thermally conductive filler (C2) is spherical aluminum particles having a D50 particle size of from 1 to 5 ⁇ m, and can have a D50 of 1 ⁇ m or more, 1.1 ⁇ m or more, even 1.5 ⁇ m or more while at the same time has a D50 particle size of 5 ⁇ m or less, and can have a D50 of 4.5 ⁇ m or less, 4 ⁇ m or less, 3.5 ⁇ m or less, 3 ⁇ m or less, 2.5 ⁇ m or less, even 2 ⁇ m or less, or even 1.5 ⁇ m or less, desirably, from 1 to 3 ⁇ m.
  • the concentration of the spherical aluminum particles (C2) is from 10 to 30 wt%, and can be 10 wt%or more, 12 wt%or more, 14 wt%or more, 15 wt%or more, 16 wt%or more, 18 wt%or more, 20 wt%or more, 21 wt%or more, 22 wt%or more, even 23 wt%or more while at the same time is 30 wt%or less, and can be 29 wt%or less, 27 wt%or less, 25 wt%or less, 23 wt%or less, or even 21 wt%or less, desirably from 15 to 30 wt%, more desirably from 20 to 25 wt%, based on the weight of the thermally conductive composition.
  • the third thermally conductive filler (C3) is a thermally conductive filler having a D50 in a range of from 0.1 to 0.6 ⁇ m, and can have a D50 of 0.1 ⁇ m or more, 0.12 ⁇ m or more, 0.15 ⁇ m or more, 0.2 ⁇ m or more, 0.3 ⁇ m or more, even 0.4 ⁇ m or more while at the same time has a D50 particle size of 0.6 ⁇ m or less, and can be 0.5 ⁇ m or less, 0.4 ⁇ m or less, 0.3 ⁇ m or less, 0.2 ⁇ m or less, or even 0.15 ⁇ m or less, desirably, from 0.1 to 0.5 ⁇ m.
  • the third thermally conductive filler particles can have any shape such as spherical, irregular, roundish or polyhedron.
  • the third thermally conductive filler may be selected from one or any combination of more than one of zinc oxide and aluminum oxide. Desirably, the third thermally conductive filler is zinc oxide particles, such as irregular zinc oxide.
  • the concentration of the third thermally conductive filler (C3) may be from 10 to 25 wt%, and can be 10 wt%or more, 11 wt%or more, 12 wt%or more, 13 wt%or more, 14 wt%or more, even 14.5 wt%or more while at the same time is 25 wt%or less, and can be 23 wt%or less, 22 wt%or less, 20 wt%or less, 21 wt%or less, 19 wt%or less, 18 wt%or less, 17 wt%or less, 15 wt%or less, or even 14.7 wt%or less, desirably, from 14 to 22 wt%, more desirably, from 14 to 20 wt%, based on the weight of the thermally conductive composition.
  • the third thermally conductive filler (C3) is irregular zinc oxide.
  • the thermally conductive filler may comprise or be free of (C4) a fourth thermally conductive filler that is other than (C1) , (C2) , and (C3) described above.
  • the concentration of the fourth thermally conductive filler (C4) is zero to 10 wt%, and can be 1 wt%or more, 2 wt%or more, 4 wt%or more, 6 wt%or more, even 8 wt%or more while at the same time is 10 wt%or less, and can be 9 wt%or less, 7 wt%or less, 5 wt%or less, 3 wt%or less, or even 1 wt%or less, based on the weight of the thermally conductive composition.
  • the thermally conductive filler (C4) may have a D50 particle size in a range of from 10 to 40 ⁇ m, and can have a D50 of 10 ⁇ m or more, 20 ⁇ m or more, 30 ⁇ m or more, even 35 ⁇ m or more while at the same time has a D50 particle size of 40 ⁇ m or less, and can have a D50 of less than 40 ⁇ m, 25 ⁇ m or less, or even 15 ⁇ m or less.
  • the fourth thermally conductive filler (C4) may be selected from one or any combination of more than one of boron nitride, diamond, magnesium oxide, and additional aluminum particles that is other than (C2) , e.g., aluminum particles having different shapes and/or D50 from (C2) .
  • the fourth thermally conductive filler (C4) is boron nitride particles.
  • the fourth thermally conductive filler (C4) particles can have any shape such as spherical, irregular, roundish or polyhedron.
  • the total concentration of aluminum particles (including (C2) and additional aluminum particles for (C4) if used) in the composition is less than 40 wt%, less than 35 wt%, or even less than 30 wt%, based on the weight of the thermally conductive composition.
  • the thermally conductive filler (C) comprises or consists of: from 45 to 60 wt%of spherical or roundish aluminum oxide particles having a D50 of 15 to 35 ⁇ m, from 20 to 25 wt%of spherical aluminum particles having a D50 in a range of 1 to 5 ⁇ m, and from 14 to 20 wt%of irregular zinc oxide particles having a D50 in a range of 0.1 to 0.5 ⁇ m, based on the weight of the thermally conductive composition.
  • the thermally conductive filler (C) may comprise or consist of: (C1) from 25 to 45 wt%of (C1-a) the aluminum oxide particles having a D50 in a range of 15 to 35 ⁇ m, and from 15 to 30 wt%of (C1-b) the aluminum nitride particles having a D50 in a range of 10 to 20 ⁇ m; (C2) from 15 to 30 wt%of spherical aluminum particles having a D50 in a range of 1 to 5 ⁇ m; and (C3) from 14 to 22 wt%of irregular zinc oxide particles having a D50 in a range of 0.1 to 0.5 ⁇ m, based on the weight of the thermally conductive composition.
  • the total concentration of thermally conductive fillers in the thermally conductive composition may be from 93 to 96 wt%, and can be 93 wt%or more, 93.5 wt%or more, 94 wt%or more, 94.4 wt%or more, 94.5 wt%or more, 95 wt%or more, 95.4 wt%or more, even 95.5 wt%or more while at the same time is 96 wt%or less, and can be 95.5 wt%or less, 95 wt%or less, even 94.5 wt%or less, based on the weight of the thermally conductive composition.
  • the thermally conductive fillers (C) in the composition are selected from the group consisting of aluminum oxide, aluminum nitride, aluminum, and zinc oxide; more desirably, the thermally conductive fillers are selected from the group consisting of aluminum oxide, aluminum, and zinc oxide.
  • the thermally conductive composition of the present invention comprises a filler treating agent (component (D) ) .
  • Component (D) may be selected from a trialkoxysilyl diorganopolysiloxane, an alkyl trialkoxysilane, or mixtures thereof.
  • Component (D) is one or a combination of more than one filler treating agent.
  • the filler treating agent may comprise, or consists of, one or any combination of more than one trialkoxysilyl diorganopolysiloxane, which is a diorganopolysiloxane that contains a -Si (OR e ) 3 group, where R e is independently in each occurrence as described for R e herein below in (IV) .
  • the trialkoxysilyl diorganopolysiloxane is a mono-trialkoxysiloxy terminated diorganopolysiloxane.
  • Suitable monotrialkoxysiloxy-terminated diorganopolysiloxanes include those having the average chemical structure (IV) : R c 3 Si [OR d 2 Si] g -Y-Si (OR e ) 3 (IV)
  • R c , R d , and R e are each independently in each occurrence hydrocarbon groups (hydrocarbyls) having 1 to 10 carbon atoms such as alkyl and aryl groups, for example, having 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, 6 or more, 7 or more, even 8 or more carbon atoms while at the same time typically having 10 or fewer, 8 or fewer, 6 or fewer, 4 or fewer, even 2 or fewer carbon atoms; and subscript g typically has a value of 20 to 150, can be 20 or more, 25 or more, 30 or more, 40 or more, 50 or more, 60 or more, 70 or more, 80 or more, 90 or more, 100 or more, or even 110 or more, while at the same time typically has a value of 150 or less, and can be 130 or less, 125 or less, 120 or less, 110 or less, 100 or less, 90 or less, 80 or less, 70 or less, 60 or less, 50 or less, 40 or less,
  • subscript g has a value in a range of 25 to 110.
  • R c , R d , and R e can be the same or different.
  • Suitable alkyl groups for R c , R d , and R e are exemplified by methyl, ethyl, propyl (e.g., iso-propyl and/or n-propyl) , butyl (e.g., isobutyl, n-butyl, tert-butyl, and/or sec-butyl) , pentyl (e.g., isopentyl, neopentyl, and/or tert-pentyl) , hexyl, as well as branched saturated hydrocarbon groups of 6 carbon atoms.
  • R c , R d , and R e each can be independently an alkyl group such as methyl, ethyl, and propyl. Desirably, each R c , R d , and R e is methyl. Suitable aryl groups for R c , R d , and R e may include phenyl and dimethyl phenyl.
  • a particularly desirable monotrialkoxysiloxy-terminated diorganopolysiloxane is a monotrimethoxysiloxy and trimethylsiloxy terminated polydimethylsiloxane such as those having the average chemical formula (CH 3 ) 3 SiO [ (CH 3 ) 2 SiO] 30 Si (OCH 3 ) 3. Suitable mono-trialkoxysiloxy terminated dimethylpolysiloxanes can be synthesized according to the teachings in US2006/0100336.
  • the filler treating agent may comprise or be free of one or a combination of more than one alkyl trialkoxysilane.
  • Suitable alkyl trialkoxysilanes include those having the chemical formula (V) : R f Si (OR g ) 3 (V)
  • R f is independently in each occurrence an alkyl group having 1 to 20 carbon atoms, and can be 6 or more, 7 or more, 8 or more, 9 or more, or even 10 or more carbon atoms, while at the same time having 20 or less, and can be 18 or less, 16 or less, 14 or less, 12 or less, or even 10 or less carbon atoms; and R g is independently in each occurrence an alkyl having 1 to 6 carbon atoms, and can be 1 or more, 2 or more, 3 or more, 4 or more, even 5 or more carbon atoms while at the same time generally having 6 or less, 5 or less, 4 or less, 3 or less, or even 2 or less carbon atoms.
  • R f is independently in each occurrence an alkyl group having 6 to 12 carbon atoms.
  • R g is desirably methyl so as to form methoxyl groups attached to the silicon atom.
  • a particularly desirable alkyl trialkoxysilane is n-decyltrimethoxysilane, n-octyltrimethoxysilane, or a mixture thereof.
  • Suitable alkyl trialkoxysilanes include n-decyltrimethoxysilane available from The Dow Chemical Company as DOWSIL TM Z-6210 Silane or under the name SID2670.0 from Gelest (DOWSIL is a trademark of The Dow Chemical Company) .
  • Component (D) the filler treating agent useful in the present invention may be present at a total concentration of from 0.5 to 2.5 wt%, and can be 0.5 wt%or more, 0.6 wt%or more, 0.7 wt%or more, 0.8 wt%or more, 0.9 wt%or more, 1.0 wt%or more, 1.2 or more, 1.3 wt%or more, 1.4 wt%or more, 1.5 wt% or more, 1.6%or more, even 1.7%or more while at the same time is typically 2.5 wt%or less, and can be 2.4%or less, 2.3 wt%or less, 2.2 wt%or less, 2.1 wt%or less, 2.0 wt%or less, or even 1.9 wt%or less, based on the weight of the thermally conductive composition.
  • the monotrialkoxysiloxy-terminated diorganopolysiloxane is present at a concentration of from 0.5 to 2.5 wt%, and can be 0.5 wt%or more, 0.6 wt%or more, 0.7 wt%or more, 0.8 wt%or more, 0.9 wt%or more, 1.0 wt%or more, 1.1 wt%or more, 1.2 wt%or more, 1.5 wt%or more even 1.6 wt%or more while at the same time is typically present at a concentration of 2.5 wt%or less, and can be 2.4 wt%or less, 2.2 wt%or less, 2.0 wt%or less, 1.8 wt%or less, even 1.7 wt%or less, based on the weight of the thermally conductive composition.
  • the alkyltrialkoxysilane may be present at a concentration of from zero to 0.4 wt%, and can be zero or more, 0.01 wt%or more, 0.05 wt%or more, 0.1 wt%or more, 0.14 wt%or more, even 0.15 wt%or more while at the same time is typically present at a concentration of 0.5 wt%or less, and can be 0.4 wt%or less, 0.3 wt%or less, or even 0.2 wt%or less, based on the weight of the thermally conductive composition.
  • the filler treating agent (D) comprises from 1.5 to 2.0 wt%of the monotrialkoxysiloxy-terminated diorganopolysiloxane and from 0.1 to 0.3 wt%of the alkyltrialkoxysilane, based on the weight of the thermally conductive composition.
  • the thermally conductive composition of the present invention may comprise or be free of one or more platinum (Pt) -based hydrosilylation reaction catalyst (component (E) ) .
  • Such hydrosilylation reaction catalyst may include compounds and complexes such as platinum (0) -1, 3-divinyl-1, 1, 3, 3-tetramethyldisiloxane (Karstedt’s catalyst) , H 2 PtCl 6 , di- ⁇ . -carbonyl di-. ⁇ .
  • platinum-cyclopentadienyldinickel platinum-carbonyl complexes, platinum-divinyltetramethyldisiloxane complexes, platinum cyclovinylmethylsiloxane complexes, platinum acetylacetonate (acac) , platinum black, platinum compounds such as chloroplatinic acid, chloroplatinic acid hexahydrate, a reaction product of chloroplatinic acid and a monohydric alcohol, platinum bis (ethylacetoacetate) , platinum bis(acetylacetonate) , platinum dichloride, and complexes of the platinum compounds with olefins or low molecular weight organopolysiloxanes or platinum compounds microencapsulated in a matrix or core-shell type structure.
  • the hydrosilylation reaction catalyst can be part of a solution that includes complexes of platinum with low molecular weight organopolysiloxanes that include 1, 3-diethenyl-1, 1, 3, 3-tetramethyldisiloxane complexes with platinum. These complexes may be microencapsulated in a resin matrix (typically, in a phenyl resin) or non-encapsulated.
  • the resin matrix for microencapsulating the complexes can be a phenyl resin, an acrylate polymer, a polycarbonate, or other resin matrix which has a melting point less than 150 °C to release Pt during heat curing. Exemplary hydrosilylation reaction catalysts are described in U.S.
  • the catalyst can be 1, 3-diethenyl-1, 1, 3, 3-tetramethyldisiloxane complex with platinum.
  • Platinum-based hydrosilylation reaction catalysts are commercially available, for example, SYL-OFF TM 4000 Catalyst, SYL-OFF 4500 Catalyst, and SYL-OFF 2700 Catalyst are available from The Dow Chemical Company (SYL-OFF is a trademark of The Dow Chemical Company) .
  • Two different catalysts e.g., E1 and E2 that activate at different temperatures can be added.
  • the two different catalysts may be (E1) 1, 3-diethenyl-1, 1, 3, 3-tetramethyldisiloxane complex with platinum, and (E2) an encapsulated platinum catalyst, such as 1, 3-diethenyl-1, 1, 3, 3-tetramethyldisiloxane complex with platinum which is encapsulated in dimethyl siloxane with phenyl silsesquioxane.
  • the amount of component (E) the platinum-based hydrosilylation reaction catalyst is sufficient to provide 0.5 part per million (ppm) to 30 ppm, and can be 0.5 ppm or more, 5 ppm or more, 10 ppm or more, 20 ppm or more, even 30 ppm or more while at the same time is generally even 30 ppm or less, of the platinum, by weight based on the weight of the thermally conductive composition.
  • the amount of the platinum-based hydrosilylation reaction catalyst may be 0.01 wt%to 0.6 wt%, and can be 0.01 wt%or more, 0.03 wt%or more, 0.04 wt%or more, 0.05 wt%or more, even 0.06 wt%or more while at the same time is typically 0.6 wt%or less, and can be 0.5 wt%or less, 0.4 wt%or less, 0.3 wt%or less, 0.2 wt%or less, 0.1 wt%or less, 0.09 wt%or less, 0.08 wt%or less, 0.07 wt%or less, or even 0.06 wt%or less, based on the weight of the thermally conductive composition.
  • the thermally conductive composition of the present invention may comprise or be free of one or a combination of more than one hydrosilylation reaction inhibitor (Component (F) , also as “inhibitor” ) .
  • Inhibitors can serve to stabilize the thermally conductive composition from premature curing and provide storage stability to the composition.
  • Suitable inhibitors include any one or any combination of more than one of acetylene-type compounds such as 2-methyl-3-butyn-2-ol; 3-methyl-l-butyn-3-ol; 3, 5-dimethyl-l-hexyn-3-ol; 2-phenyl-3-butyn-2-ol; 3-phenyl-l-butyn-3-ol; 1-ethynyl-1-cyclohexanol; 1, 1-dimethyl-2-propynyl) oxy) trimethylsilane; and methyl (tris (l, l-dimethyl-2-propynyloxy) ) silane; ene-yne compounds such as 3-methyl-3-penten-l-yne and 3, 5-dimethyl-3-hexen-l-yne; triazols such as benzotriazole; hydrazine-based compounds; phosphines-based compounds; mercaptan-based compounds; cycloalkenylsilox
  • the concentration of component (F) the inhibitor may be zero to 0.1 wt%, and can be 0.001 wt%or more, 0.002 wt%or more, even 0.003 wt%or more while at the same time is typically 0.1 wt%or less, and can be 0.05 wt%or less, 0.01 wt%or less, 0.005 wt%or less, 0.004 wt%or less, even 0.003 wt%or less, based on the weight of the thermally conductive composition.
  • the thermally conductive composition of the present invention may comprise or be free of other optional components including any one or any combination of more than one of the following components: heat stabilizers and/or pigments (such as copper phthalocyanine powder) , thixotropic agents, fumed silica (desirably, surface treated) , and spacer additives (such as glass beads) .
  • heat stabilizers and/or pigments such as copper phthalocyanine powder
  • thixotropic agents such as fumed silica (desirably, surface treated)
  • fumed silica desirably, surface treated
  • spacer additives such as glass beads
  • the total concentration for these additional components can be in a range of from zero to 0.6 wt%, and can be zero or more, 0.1 wt%or more, 0.2 wt%or more, 0.3 wt%or more, 0.4 wt%or more, even 0.5 wt%or more while at the same time is typically 0.6 wt%or less, and can be 0.5 wt%or less, 0.4 wt%or less, 0.3 wt%or less, 0.2 wt%or less, 0.1 wt%or less, or even 0.05 wt%or less, based on the weight of the thermally conductive composition.
  • the thermally conductive composition of the present invention may comprise or be free of one or a combination of more than one solvent.
  • concentration of solvent can be less than 0.01 wt%, less than 0.005 wt%, or even zero, based on the weight of the thermally conductive composition.
  • the thermally conductive composition is substantially free of a solvent, i.e., contains no solvent or may contain trace amounts of residual solvents from delivery of starting materials in the composition.
  • the concentration of the solvent can be measured by gas chromatography (GC) . If the amount of solvents is too high, voids tend to be generated during curing the thermally conductive composition, which gives poor surface appearance or even results in a decreased thermal conductivity.
  • the solvent can be an organic solvent such as an aliphatic or aromatic hydrocarbon, which is saturated or unsaturated, such as benzene, toluene, xylene, hexane, heptane, octane, iso-paraffin, hydrocarbon compounds of 8 to 18 carbon atoms and at least one aliphatic unsaturation per molecule such as tetradecene; a ketone such as acetone, methyl ethyl ketone, or methyl isobutyl ketone; an ester acetate such as ethyl acetate or isobutyl acetate; an ether such as a glycol ether such as propylene glycol methyl ether, dipropylene glycol methyl ether, and propylene glycol n-butyl ether, diisopropyl ether or 1, 4-dioxane; a cyclic or linear siloxane having an average degree of polymerization from 3 to
  • the thermally conductive composition of the present invention achieves an extrusion rate (ER) of 40 g/min or more.
  • the thermally conductive composition of the present invention upon curing, provides a thermal resistance (TR) of no more than 0.12 °C*cm 2 /W and a thermal conductivity (TC) of at least 6.0 W/m*K.
  • TR thermal resistance
  • TC thermal conductivity
  • the thermally conductive composition can have an extrusion rate of 40 g/min or more, can be 45 g/min or more, 55 g/min or more, 60 g/min or more, 80 g/min, 90 g/min or more, or even 100 g/min or more.
  • ER is a useful characteristic as a measure of extrudability, viscosity, dispensability, which, for example, makes the thermally conductive composition easily dispensable for applying onto another material such as electronic components or heat sinks and ensures application efficiency during a production process.
  • TR can be measured according to ASTM D-5470 at a pressure of 40 psi (275.8 kilopascals) , for example, at 80 °C for 15 minutes using a thermal resistance and conductivity measurement apparatus such as LonGwin Model LW 9389 TIM thermal conductivity and resistance tester.
  • the thermally conductive composition can provide a TR of 0.11°C*cm 2 /W or less, 0.10°C*cm 2 /W or less, 0.09°C*cm 2 /W or less, or even 0.08°C*cm 2 /W or less.
  • TC properties can be measured using a hot disk according to ISO 22007-2 with cured samples.
  • the thermally conductive composition can provide a TC of 6.0 W/m*K or more, 6.5 W/m*K or more, 7 W/m*K or more, or even 8.0 W/m*K or more.
  • the thermally conductive composition can achieve a Bond Line Thickness (BLT) of 80 micrometers ( ⁇ m) or less, and can have a BLT of 70 ⁇ m or less, 60 ⁇ m or less, or even 50 ⁇ m or less. Further details for evaluating the above properties may be found in the Examples section below.
  • both a low TR and a high TC (affording an efficient thermal dissipation) makes the thermally conductive composition particularly useful as a thermally conductive interface material to efficiently transfer heat between two components with a thin gap up to 80 ⁇ m or less.
  • Thermally conductive interface materials are typically used to thermally couple heat generating components and heat dissipating components, especially in electronics.
  • the present invention also relates to a method of preparing the thermally conductive composition, the method comprising: admixing the alkenyl-functional polyorganosiloxane, the SiH crosslinker, the thermally conductive fillers, the filler treating agent, and optionally, the hydrosilylation reaction catalyst and the inhibitor and other optional components described above.
  • the present invention also includes a process for using the thermally conductive composition described above.
  • the process comprises the steps of: a) applying the thermally conductive composition on an electronic component, and b) curing the thermally conductive composition by heat.
  • the applying of the thermally conductive composition may involve dispensing or extruding the thermally conductive composition. Due to the above described properties of the thermally conductive composition such as excellent dispensability and conformability as indicated by the high ER above, the process allows for automated dispensing and assembly (i.e., increased productivity) with minimal stress applied to fill in intricate geometries and diverse gaps, therefore avoiding potential damages to the electronic components.
  • the low BTL described above also enables the composition to be applied to thin gaps.
  • the two components where the thermally conductive composition is the components of an electronic article.
  • the thermally conductive composition can be between and in contact with one electronic component and a heat dissipating component such as a heat sink, or between and in contract with two electronic components of the electronic device, where at least one electronic component generates heat when the electronic device is in operation.
  • Examples of the electronic components which generate heat during the electronic device is operated include central processing units (CPU) , graphics processing units (GPU) , memory chips, driver chips and optical modules.
  • the thermally conductive composition can be applied on one or two electronic components which generate heat. Examples of the heat dissipating components include a heat sink, cooling plate/pad, cooling tube, and metal cover.
  • the curing of the thermally conductive composition can be conducted at room temperature or by heat, for example, at temperatures greater than 25 °C, and can be greater than 40 °C, or greater than 80 °C.
  • the duration time for curing may vary depending on the temperatures, typically 0.5 to 24 hours.
  • the thermally conductive composition can be cured at room temperature, or by heat generated by the electronic component. Desirably, when the electronic device is in operation, the heat generated from at least one electronic component cures the thermally conductive composition typically within several hours, thereby forming the cured material.
  • the process does not involve (that is, is free of) an extra procedure for removal of the solvent, e.g., stripping off or evaporating the solvent.
  • the thermally conductive composition enables the process for using the composition without the aid of a solvent and also makes it applicable to dispense (e.g., by extrusion) the composition directly onto components of articles without requiring addition of solvents to the composition before use.
  • the present invention further includes an electronic article comprising the thermally conductive composition and at least the two components where the thermally conductive composition is between and in contact with the two components of the article.
  • the thermally conductive composition can be in either a cured or non-cured form.
  • the article of is useful as a device benefiting from efficient thermal conduction and good electrical insulation between components, such as a heat generating device and at least one of a heat sink, cooling plate, metal cover or other heat dissipating component.
  • the two components can be the same or different.
  • the electronic article is useful as an electronic device.
  • Examples of the electronic devices include optical modules, smartphones, digital cameras, computers, pad devices, servers and base stations for communication, power inverters, DC (direct current) -to-DC converters, advanced driver assistance systems (ADAS) , and battery packs in electric vehicles (EV) .
  • power inverters DC (direct current) -to-DC converters
  • ADAS advanced driver assistance systems
  • EV battery packs in electric vehicles
  • Viscosities were measured by ASTM D445-21 at 25 °C using a glass capillary Cannon-Fenske type viscometer. D50 was measured using a Mastersizer TM 3000 laser diffraction particle size analyzer from Malvern Instruments.
  • Formulations for the samples are in Tables 2 and 3, with the amount of each component reported in grams (g) .
  • Samples were prepared by using a SpeedMixer TM DAC 400 FVZ mixer from FlackTek Inc. (South Carolina, USA) to mix the components together.
  • SpeedMixer To a cup of the SpeedMixer add the Vi Polymer A-1, SiH Crosslinkers B-1 and B-2, Treating Agents D-1 and D-2, TC filler C3, and TC filler C4 if present. Mix at 1000 revolutions per minute (RPM) for 20 seconds, then 1500 RPM for 20 seconds.
  • thermally conductive composition samples were evaluated for extrusion rate and thermal conductivity, and appearance according to the following test methods:
  • Thermal resistance ( “TR” ) was measured according to ASTM D-5470 using LonGwin Model LW 9389 TIM thermal resistance and conductivity measurement apparatus from Longwin Science and Technology Corporation, Taiwan. Liquid samples were applied between a guarded central hot and cold plates where the hot plate was set at 80 °C and maintained for 15 minutes (min) . A pressure of 40 psi was used to maintain contact to the plates. Thermal resistance was recorded. Acceptable thermal resistance is 0.12 °C*cm 2 /W or less.
  • Bond line thickness ( “BLT” ) was measured using ARES G2 Rheometer by dispensing a sample material on a substrate, pressing a plate (with a diameter of 8 mm) onto the sample with a pressure of 40 psi, compressing the sample to the minimum bondline thickness, and recording the bondline thickness of the sample after 180 seconds.
  • Extrusion rate ( “ER” ) for a sample was determined using Nordson EFD dispensing equipment.
  • the sample material was packaged into a 30 cubic centimeter syringe with a 2.54 millimeter (mm) opening (EFD syringe form Nordson Company) .
  • the sample was dispensed at 25 °C through the opening by applying a pressure of 0.62 MPa to the syringe.
  • the mass of the sample in grams (g) extruded after one minute corresponds to the extrusion rate in grams per minute (g/min) .
  • the objective of the present invention is to achieve an extrusion rate of at least 40 g/min.
  • some samples were powdery pastes that could not be extruded so they are reported as having an ER of 0 (and other properties were not measured, thus reporting as “NA” ) .
  • Thermal conductivity ( “TC” ) was determined using a hot disk according to ISO 22007-2.
  • the thermal conductivity of cured samples was measured by Hot Disk TPS 2500 S instrument with a 3.189 mm Kapton sensor (model 5465) .
  • the cured samples were prepared by curing the curable thermally conductive composition samples prepared above at 100 °C for 60 min with dimension of 25mm*25mm*8mm.
  • the objective of the present invention is to achieve a thermal conductivity of at least 6.0 Watts per meter*Kelvin (W/m*K) .
  • V The grease composition surface is uniform and smooth.
  • the grease composition surface is coarse and granular.
  • the grease composition is powdery and cannot form a paste.
  • Table 2 contains characterization results for IEs 1-6 samples. As shown in Table 2, all IEs samples comprise the novel combination of specific amounts of at least three TC fillers including (C1) Al 2 O 3 particles with a D50 in a range of 10-40 ⁇ m, (C2) spherical Al particles with a D50 in a range of 1-5 ⁇ m, and (C3) ZnO particles with a D50 in a range of 0.1-0.6 ⁇ m where IEs 1, 3 and 7 further comprise AlN filler with a D50 of 10 ⁇ m or 20 ⁇ m.
  • TC fillers including (C1) Al 2 O 3 particles with a D50 in a range of 10-40 ⁇ m, (C2) spherical Al particles with a D50 in a range of 1-5 ⁇ m, and (C3) ZnO particles with a D50 in a range of 0.1-0.6 ⁇ m where IEs 1, 3 and 7 further comprise AlN filler with a D50 of 10 ⁇ m or 20
  • All IEs samples with uniform and smooth surface achieved TC of at least 6 W/m*K, TR of no higher than 0.12 °C*cm 2 /W, and ER of at least 40 g/min or even greater than 53 g/min (IEs 2 and 4-6) . Moreover, all IE samples achieved a BLT of 80 ⁇ m or less.
  • “Wt%filler” refers to weight percentage of total thermally conductive fillers relative to the total weight of all components in the sample.
  • volume%filler refers to volume percentage of total thermally conductive fillers relative to the total volume of all components in the sample.
  • SiH/Vi ratio refers to molar ratio of SiH functionality from the crosslinker to vinyl functionality in the sample.
  • Wt%Al filler (1-5 ⁇ m) refers to wt%of aluminum particles with a D50 in a range of 1 to 5 ⁇ m relative to the total weight of all components in the sample.
  • CE 1 sample comprising spherical Al filler (D50: 1.5 ⁇ m) at a lower concentration of 7.6%failed to achieve both the ER and TR requirements.
  • CE 2 sample that contains TC filler C1 with a D50 of 10-40 ⁇ m in an amount less than the claimed concentration gave an undesirably low ER and high TR.
  • CE 3 sample comprising spherical Al filler with a D50 of 1.5 ⁇ m at a concentration higher than the claimed concentration failed to meet the requirement for ER.
  • CE 4 sample using spherical Al filler with a D50 of 9 ⁇ m to replace spherical Al filler with a D50 of 1-5 ⁇ m gave poor processability, thermal performance cannot be measured due to the powdery state.
  • CE 5 sample comprising Al 2 O 3 particles with a D50 of 5 ⁇ m that is smaller than 10 ⁇ m gave lower TC and ER than the requirements.
  • CE 7 sample that does not comprise spherical Al filler with a D50 of 1-5 ⁇ m but irregular AlN gave a powdery paste (that is poor processability) and TC cannot be measured.
  • CE 8 sample comprising 40 wt%of spherical Al filler with a D50 of 16 ⁇ m and 40 wt%of spherical Al filler with a D50 of 1.5 ⁇ m at a total concentration of Al fillers of 80 wt%gave undesirably low ER.

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Abstract

Une composition thermoconductrice contient, sur la base du poids de la composition thermoconductrice, (A) de 1,0 à 4,0 pour cent en poids d'un polyorganosiloxane à fonction alcényle ; (B) un agent de réticulation polysiloxane à fonction silyle-hydrure qui contient au moins deux groupes silyle-hydrure par molécule ; (C) de 93 à 96 pour cent en poids de charges thermoconductrices contenant des quantités spécifiques de (C1-a) particules d'oxyde d'aluminium ayant un D50 dans une plage de 10 à 40 micromètres, et éventuellement de (C1-b) particules de nitrure d'aluminium ayant un D50 dans une plage de 10 à 40 micromètres, de (C2) particules d'aluminium sphériques ayant un D50 dans une plage de 1 à 5 micromètres, et de (C3) une troisième charge thermoconductrice ayant un D50 dans une plage de 0,1 à 0,6 micromètre et choisie dans le groupe constitué par des particules d'oxyde de zinc, des particules d'oxyde d'aluminium et des mélanges de celles-ci ; et (D) un agent de traitement de charge.
PCT/CN2023/122025 2023-09-27 2023-09-27 Composition de silicone thermoconductrice Pending WO2025065334A1 (fr)

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TW113133819A TW202513716A (zh) 2023-09-27 2024-09-06 導熱聚矽氧組成物

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN121574711A (zh) * 2026-01-26 2026-02-27 浙江三元电子科技有限公司 一种导热相变材料及其制备方法、应用

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Publication number Priority date Publication date Assignee Title
US3159601A (en) 1962-07-02 1964-12-01 Gen Electric Platinum-olefin complex catalyzed addition of hydrogen- and alkenyl-substituted siloxanes
US3220972A (en) 1962-07-02 1965-11-30 Gen Electric Organosilicon process using a chloroplatinic acid reaction product as the catalyst
US20060100336A1 (en) 2002-11-08 2006-05-11 Hiroshi Fukui Heat conductive silicone composition
WO2014017671A1 (fr) 2012-07-27 2014-01-30 Dow Corning Toray Co., Ltd. Microparticules et composition d'organopolysiloxane durcissable les contenant
US20230032719A1 (en) * 2020-03-05 2023-02-02 Dow Global Technologies Llc Shear thinning thermally conductive silicone compositions
US20230212447A1 (en) * 2020-10-28 2023-07-06 Dow Silicones Corporation Non-curable thermally conductive pituitous silicone material

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3159601A (en) 1962-07-02 1964-12-01 Gen Electric Platinum-olefin complex catalyzed addition of hydrogen- and alkenyl-substituted siloxanes
US3220972A (en) 1962-07-02 1965-11-30 Gen Electric Organosilicon process using a chloroplatinic acid reaction product as the catalyst
US20060100336A1 (en) 2002-11-08 2006-05-11 Hiroshi Fukui Heat conductive silicone composition
WO2014017671A1 (fr) 2012-07-27 2014-01-30 Dow Corning Toray Co., Ltd. Microparticules et composition d'organopolysiloxane durcissable les contenant
US20230032719A1 (en) * 2020-03-05 2023-02-02 Dow Global Technologies Llc Shear thinning thermally conductive silicone compositions
US20230212447A1 (en) * 2020-10-28 2023-07-06 Dow Silicones Corporation Non-curable thermally conductive pituitous silicone material

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN121574711A (zh) * 2026-01-26 2026-02-27 浙江三元电子科技有限公司 一种导热相变材料及其制备方法、应用

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