WO2016082138A1

WO2016082138A1 - Composition for electrically insulating polymer-inorganic hybrid material with high thermal conductivity

Info

Publication number: WO2016082138A1
Application number: PCT/CN2014/092338
Authority: WO
Inventors: Yan Huang; Yunfeng Yang; Hongyu Chen; Valeriy Ginzburg; Jian Yang
Original assignee: Dow Global Technologies Llc
Priority date: 2014-11-27
Filing date: 2014-11-27
Publication date: 2016-06-02
Also published as: TW201627410A

Abstract

A composition containing a continuous phase called sea phase and discrete, isolated dispersed domains in and surrounded by the continuous phase called island phase. The continuous phase contains thermally conductive, electrically insulative fillers and the isolated phase contains thermally conductive fillers that could be electrically conductive. A polymer composite material formed from the composition has high thermal conductivity with good electrical insulation suitable for a thermal management component.

Description

COMPOSITION FOR ELECTRICALLY INSULATING POLYMER-INORGANIC HYBRID MATERIAL WITH HIGH THERMAL CONDUCTIVITY

Field of the invention

The present invention relates to a composition for an insulating polymer-inorganic hybrid material with high thermal conductivity suitable for a thermal management element of electronic devices， to a polymer material and to an article containing the material.

Background of the invention

Thermal management is critical in every aspect of the microelectronics space， such as integrated circuits (IC) ， light-emitting diode (LED) ， power electronics， displays and photovoltaics. The performance of these devices can be directly affected by operating temperature. Lowering the operating temperature of these devices increases lifetime and improves performance， as compared to operation at higher temperatures.

In solid state lighting technologies， there is a strong need to improve heat management. Proper dissipation of heat in LED devices is critical to their reliable long-term operation. Failure to adequately manage the heat can have an undesirable impact on the performance of LEDs. Prolonged exposure to excessive operating temperatures can lead to irreversible damage to the semiconductor components within the LED die， resulting in lowered light outputs， changes to the color rendering index， and significantly reduced LED lifetimes. Therefore， a material with higher heat conductive property is desired for heat management of LED devices.

A heat sink in an electronic system is a passive component that cools a device by dissipating heat into the surrounding air. Heat sinks are used to cool electronic components or semiconductor components such as high-power semiconductor devices， and optoelectronic devices such as higher-power lasers and light emitting diodes (LEDs) . Traditional heat sink uses aluminum fins and several copper heat pipes for cooling of high-heat-dissipation processors. A heat sink is designed to increase the surface area in contact with the cooling medium surrounding it， such as the air. However， the metals are heavy and difficult to process a complex form. Therefore， it has been required to develop a material with higher thermal conductivity as well as lower specific gravity and processing cost as alternative to metal.

Although polymer materials are light and easy to processing， their low thermal conductive property is a barrier of application to a heat sink. To increase thermal conductivity of polymer materials， high amounts of thermally conductive fillers such as boron nitride are added in polymer materials， see e.g. EP2094772B， WO2013012685A， US20090069483A， WO2012114309A， WO2009043850A， WO2011106252A， WO2012114310A， US20080265202A and US2012022998 1A. However， since very high filler loading is needed for thermal conductive polymer materials， it causes a difficulty for processing because very high pressure is now required to mold such polymer.

Carbon based fillers such as graphite have much higher thermal conductivity than boron nitride. Some of the above references disclose the use of carbon based fillers in addition to the thermal conductive fillers. However， the electrical conductivity of carbon based fillers is high， so the electrical insulation of polymer materials comprising such filler is poor.

Accordingly， an electrically insulating polymer-based material with easy processability and high thermal conductivity suitable for a thermal management element of electronic devices is desired.

Summary of the invention

Inventors of this invention have now found a technical approach which maintains electrical insulating properties while incorporating electrically conductive filler in a polymer material. This approach uses an island-sea polymer structure in a composition having at least two resins. One resin forms a continuous phase called sea phase， and another resin forms discrete， isolated dispersed domains in and surrounded by the continuous phase. Such domains can be called the island phase. Thermally conductive， electrically conductive fillers are incorporated in an island phase resin and thermally conductive fillers with low electrical conductivity (or electrically insulative properties) are incorporated in a sea phase resin. The discrete phases may be formed by phase separation of the two resins during melt blending. Alternatively， very small particles (e.g. of a higher melting point thermoplastic or a cured or partially cured thermoset) of the island phase material may be dispersed in a melt of the sea phase. The resulting polymer composite material has high thermal conductivity with good electrical insulative properties.

Therefore， one aspect of the invention relates to a composition comprising (a) a continuous phase comprising a first resin and at least one thermally conductive， electrically insulative filler and (b) a discontinuous phase comprising a second resin and at least one thermally conductive， electrically conductive filler， in which the continuous phase surrounds discrete domains of the discontinuous phase.

Another aspect of the invention relates to a method to prepare the composition， comprising the steps of (a) preparing a first resin mixture comprising the first resin and at least one thermal conductive， electrical insulative filler and a second resin mixture comprising the second resin and at least one thermal conductive， electrical conductive filler separately， and (b) mixing the first resin mixture and the second resin mixture under the condition for the second resin mixture which phase separates with the first resin mixture and forms discrete domains of a discontinuous phase surrounded by the first resin mixture.

Further aspect of the invention relates to a polymer composite material formed from the above composition and to an article comprising the polymer composite material.

Detailed description of the invention

As used throughout this specification， the abbreviations given below have the following meanings， unless the context clearly indicates otherwise： g＝gram (s) ； mg＝milligram (s) ； m＝meter (s) ； mm＝millimeter (s) ； cm＝centimeter (s) ； min. ＝minute (s) ； s＝second (s) ； hr. ＝hour (s) ； ℃＝degree (s) C＝degree (s) Celsius； K＝kelvin； W＝watt； Ω＝ohm； wt％＝weight percent (s) ； vol％＝volume percent (s) . Throughout this specification， the word ‘resin’ and ‘polymer’ is used interchangeably.

The composition of the invention comprises a continuous phase and a discrete domain of a discontinuous phase surrounded by the continuous phase. The continuous phase comprises a first resin (resin A) and at least one thermally conductive， electrically insulative filler (Filler-1) and the discontinuous phase comprises a second resin (resin B) and at least one thermal conductive， electrical conductive filler (Filler-2) . The structure of those resins is called as island-sea structure. The second resin preferably phase separates from the first resin during blending. Alternatively， small particulates of resin B may be dispersed in melt of resin A.

(a) Resin A and resin B

Resin A and resin B used in the invention may be selected from a wide variety of resins provided those resins forms island-sea structure. Resin A and resin B may be selected from thermoplastic resins， thermosetting resins， or mixture thereof. A cured or partially cured thermosetting resin can be used as Resin A and/or Resin B. The resins can also be selected from an oligomer， a homopolymer， a copolymer， a block copolymer， an alternating block copolymer， a random polymer， a random copolymer， a random block copolymer， a graft copolymer， a star block copolymer， a dendrimer， or the like， or a combination comprising at least one of the foregoing polymers.

Examples of the resins include， polyamide， nylons， polyphenylene sulfide (PPS) ， polyolefin， polyacetal， polycarbonate (PC) ， polystyrene (PS) ， polyester， liquid crystal polyester (LCP) ， polyethylene telephthalate (PET) ， acrylonitrile-butadiene-stylene (ABS) ， Polytetrafluoroethylene (PTFE) polyvinyl fluoride PVF， polyoxymethylene (POM) ， polybutadiene terephthalate (PBT) ， Polyphenylene Oxide (PPO) ， polyetheretherketone (PEEK) ， polyetherimide (PEI) and polymethyl methacrylate (PMMA) .

The ratio of resin A/resin B by volume is preferably 99/1 or less， more preferably 70/30 or less. The ratio of resin A /resin B by volume is preferably 60/40 or more， more preferably 65/35 or more.

Preferably， the melting point of resin A is lower than the melting point of resin B. More preferably， the melting point of resin A is 5℃ lower than the melting point of resin B， further preferably the melting point of resin A is 10℃lower than the melting point of resin B. The most preferably， the melting point of resin A is 20℃ lower than the melting point of resin B.

Preferably， the viscosity of resin A at the processing temperature of a polymer composite material is lower than the one of the resin B. The viscosity of resins can be measured according to ASTM D2196-99.

(b) Continuous phase (sea phase)

The continuous phase (sea phase) of the composition comprises resin A and at least one thermally conductive， electrically insulative filler (Filler-1) .

The resin A is disclosed above. Filler-1 has intrinsic thermal conductivity (at room temperature) of 20 W/mK or more. More preferably， the intrinsic thermal conductivity of the filler is 30 W/mK or more. The intrinsic thermal conductivity of a filler can be measured according to ASTM E1461-01 method. The resistivity of Filler-1 is 10¹² Ω·cm or more， preferably 10¹⁵ Ω·cm or more. The resistivity of a filler can be measured according toASTM D257-01.

Examples of Filler-1 include boron nitride (BN) ， aluminum nitride (AlN) ， alumina (Al₂O₃) ， magnesia (MgO) ， silicon oxide (SiO₂) ， silicon carbide (SiC) ， zinc oxide (ZnO) ， berillia (BeO) and graphene oxide. Preferably， the filler is selected from boron nitride， aluminum nitride and graphene oxide. The filler may be used as a mixture.

The particle size of the filler is 0.1 micro meter or more， preferably 10 micro meter or more. The larger the filler， the better thermal conductivity would be. However， the particle size of the filler is 300 micro meter or less， preferably 100 micro meter or less， because of the influence of mechanical properties and processability of the composite. Particle size of the filler can be analyzed by laser diffraction method. ‘Particle size’ in this application means median size (D50， the size at which 50％ of a sample is comprised of smaller particles) .

The content of Filler-1 in a continuous phase (sea phase) is preferably 20 volume ％ or more， more preferably 50 volume ％ or more， the most preferably 60 volume ％ or more based on the entire volume of the sea phase. At the same time， the content of the filler is preferably80 volume ％ or less， more preferably 70 volume ％ or less， the most preferably 65 volume ％ or less based on the entire volume of sea phase. Although the content of Filler-1 in sea phase is disclosed as volume ％， if its content is disclosed as weight ％， the preferable content of Filler-1 is 20 to 85 weight ％ based on the weight of the sea phase.

(c) Discontinuous phase (island phase)

The discontinuous phase (island phase) of the composition comprises resin B and at least one thermally conductive， electrically conductive filler (Filler-2) .

The resin B is disclosed above. Filler-2 has intrinsic thermal conductivity at room temperature of 20 W/m·K or more. More preferably， the intrinsic thermal conductivity of the filler is 30 W/mK or more. At the same time， the electric resistivity of the filler is 10^-6 Ω·cm or less， preferably 10^-3 Ω·cm or less. The thermal conductivity and resistivity of a filler can be measured same as the above.

Examples of the filler include graphite， carbon nanotube， carbon fiber， carbon black， metal particle， and graphene. The mixture of two or more fillers may also be used. Preferably， the filler is graphite. The graphite can be synthetically produced or naturally produced， or can be expanded graphite. Naturally produced graphite includes three types of graphite， i.e. crystalline flake graphite， amorphous graphite and crystal vein graphite. Expanded graphite can be made by immersing natural flake graphite in a bath of chromic acid， then concentrated sulfuric acid， which forces the crystal lattice planes apart， thus expanding the graphite. After expanding， functional acids and hydroxyl groups are introduced and thus promote affinity of expanded graphite to organic compounds and polymers. Besides， expanded graphite is thermally more conductive when compared to conventional carbon materials such as standard graphite. Expanded graphite is the most preferable as Filler-2 of the invention.

The particle size of the filler is preferably 0.05 micro meter or more， more preferably 0.1 micro meter or more， the most preferably 10 micro meter or more. The particle size of the filler is preferably 100 micro meter or less， more preferably 20 micro meter or less. Particle size of the filler can be analyzed by by laser diffraction method. Particle size means median size (D50) .

The content of the Filler-2 in the discontinuous phase (island phase) is preferably 20 volume ％ or more， more preferably 60 volume ％ or more， the most preferably 65 volume ％ or more based on the entire volume of the island phase. At the same time， the content of the filler is preferably 80 volume ％ or less， more preferably 75 volume ％ or less， the most preferably 70 volume ％ or less based on the entire volume of island phase. Although the content of Filler-2 in island phase is disclosed as volume ％， if its content is disclosed as weight ％， the preferable content of Filler-2 is 40 to 90 weight ％ based on the weight of the island phase.

The dispersion size of the island phase in the composition is preferably 10 micrometer or more， more preferably 50 micro meter or more. The dispersion size of the island phase in the composition is preferably 500 micro meter or less， more preferably 200 micro meter or less.

The composition used in the invention can comprise other additives such as flame retardant， antioxidant， UV stabilizer， plasticizer， coupling agent， mold release agent， pigment and dye. Those additives can be added to at least one of sea phase or island phase.

Examples of flame retardant used for the composition include antimony oxides， halocarbon， halogenated ester， halogenated ether， brominated flame retardant agent， and halogen free compounds such as organophosphorus compounds， organonitrogen compounds， intumescent flame retardants.

Examples of antioxidant used for the composition include sodium sulfite， sodium pyrosulfite， sodium hydrogen sulfite， sodium thiosulfate and dibutyl phenol.

Examples of UV stabilizer used for the composition include benzophenones， benzotriazoles， substituted acrylates， aryl esters and compounds containing nickel or cobalt salts.

Examples of plasticizer used for the composition include phthalates benzoates， dibenzoates， thermoplastic polyurethane plasticizers， phthalate esters， naphthalene sulfonate， trimellitates， adipates， sebacates， maleates， sulfonamides， organophosphates， polybutene.

Examples of coupling agent used for the composition include chrome complex， silane coupling agent， titanate coupling agent， zirconium coupling agent， magnesium coupling agent and tin coupling agent.

Examples of mold release agent used for the composition include inorganic mold release agent such as talcum powder， mica powder， argil and clay； organic mold release agent such as aliphatic acid soap， fatty acid， paraffin， glycerol and vaseline； polymer mold release agent such as silicone oil， polyethylene glycol and polyethylene.

Examples of pigment or dye used for the composition of the invention include chromate， sulfate， silicate， borate， molybdate， phosphate， vanadate， cyanate， sulfide， azo pigment， phthalocyanine pigment， anthraquinone， indigo， quinacridone and dioxazinedyes.

The method to prepare the composition of the invention comprises the steps of (a) preparing a first resin mixture comprising a first resin (resin A) and at least one thermal conductive， electrical insulative filler (Filler-1) and a second resin mixture comprising a second resin (resin B) and at least one thermal conductive， electrical conductive filler (Filler-2) separately， and (b) mixing the first resin mixture and the second resin mixture under the condition for the second resin mixture forms discrete domains of a discontinuous phase surrounded by the first resin mixture.

The blending of resin A and Filler-1 or the blending of resin B and Filler-2 can be conducted by any known methods， such as melt blending or solution blending. The melt blending can be conducted using a melt-mixer such as HAAKE Rheomix mixer， single or twin-screw extruder， kneader， Banbury mixer to until homogeneously. For example， the Fillers-1 (BN) and resin A (PA) can be melt blending by using Haake mixter (Polylab brand) at 270 to 300 ℃ for 5 to 25 minutes at mixing speed of 20 to 60 rpn/minutes.

The mixing of the first resin mixture and the second resin mixture is conducted at the higher temperature than the melting point of resin A. Preferably the mixing is conducted at the temperature higher than melting point of resin A and lower than the melting point of resin B. The condition of mixing the two resin mixtures is a key in the method of this invention. The inventors of this invention found that the larger island phase size increases the thermal conductivity of the cured polymer material formed fiom the composition. Therefore， the condition of mixing the two resin mixtures is controlled so that the island phase size is 10 micro meter or more. More preferably， the condition of mixing the two resin mixtures is controlled so that the island phase size is 20 micrometer or more， further preferably 30 micro meter or more.

To get larger size of island phase， the mixing should not be conducted fully and completely， because the fully mixing will lead to a much smaller island phase domains. The mixing speed should be slow and mixing time should be short compared with the condition which a composition is fully and completely mixed. Preferably， mixing speed is 80 ％ or less， more preferably mixing speed is 70 ％ or less compare with the condition which the composition is fully and completely mixed. The mixing time is preferably 50 ％ or less， more preferably 30 ％ or less compare with the condition which the composition is fully and completely mixed. For example， when Haake mixer is used to mixing resin mixtures， mixing speed is preferably 30 rpm or less and mixing time is 10 minutes or less， compare with the fully and completely mixed condition (20 minutes， at 50 rpm) .

The polymer composite material of the invention can be formed from the composition disclosed above. The polymer material is obtained by pouring or injecting the composition in a mold then cool down the composition. If at least one of resin A and resin B is thermosetting resin， a curing step is further added to the above process. For example， a thermoplastic resin is used as a resin A and a pre-half-cured thermosetting resin is used as a resin B， the composition is poured in a mold at higher temperature of melting point of resin A， then heated to the temperature of which resin B is fully cured. The polymer composite material formed from such process has an advantage of being more electrically insulative， since filler-2 incorporated in the discontinuous phase will be less likely to diffuse out from the discontinuous phase.

The cured polymer material has high thermal conductivity as well as good insulative properties. The in-plane thermal conductivity of the cured thermoset is 8 W/m·K or more， preferably 10 W/m·K or more. More preferably， the thermal conductivity of the cured thermoset is 12 W/m·K or more. The electrical resistivity (volume resistance) of the material is preferably 1X10¹² Ω·cm or more， more preferably 1X10¹³ Ω·cm or more.

The article of this invention comprises a heat source and a thermal management component located in proximity to the heat source. The thermal management component comprises a polymer composite material formed from the composition described above. Since the polymer composite material used in the invention has high thermal conductivity， the heat generated by the heat source is adequately transferred and removed from the heat source.

Examples of such heat source comprise integrated circuit (IC) chip， light-emitting diode (LED) ， power electronics， displays and photovoltaics.

The thermal management component of the invention could be a heat sink or connecting material with heat source and heat sink. As disclosed above， heat sink is used to cool electronics components or semiconductor components such as high-power semiconductor devices， and optoelectronic devices such as higher-power lasers and light emitting diodes (LEDs) . Since the polymer composite material of our invention has high thermal conductivity， the heat generated by the heat source is effectively transferred and removed from the heat source.

Other examples of the thermal management components are， electronic packaging agent， sealing agent， adhesive agent， electric switch， printed circuit board and wire coating.

The article of the invention could be a substrate with electronics element or semiconductor element such as IC chips or power electronics (heat source) and plastic substrate or plastic film contacted to such heat source (athermal management component) . IC chips or other electronics elements are normally mounted on a laminated plastic substrate such as epoxy or polyimide resin. Ceramic substrate such as aluminum or aluminum nitrate is also used as a substrate for power electronics because of the need for heat management generated by the power electronics. Since ceramic substrate is difficult to laminate or process， plastic substrate with high thermal conductivity is desired. The polymer composite material of our invention can be used for the purpose.

The article of the invention could be a system comprising electronics device (heat source) and a covering thermoset resin of the device (athermal management component) . To protect electronics devices from mechanical damages， electronics devices are covered by a material such as thermoset resin. Since electronics devices generate heat， thermal management of the material is required. The polymer composite material of our invention with high thermal conductivity can be used for the purpose. Example of such article is LED lightning system with LED light encapsulated by the cured thermoset.

The article of the invention could be a solid state lightening system comprising LED light (heat source) and a base which is mounted the LED light (a thermal management component) . In solid state lightning system， LED light is mounted on a base and surrounded by a side-wall. Since the LED light generates heat， thermal management of the solid state lightning system is required. The polymer composite material of our invention with high thermal conductivity can be used for the purpose.

Examples

Inventive Example 1

Twenty nine point sixty grams (29.60g) of Nylon 66 (， product name is Zytel 101F， supplied from Dupont) were loaded in a mixer (Haake mixer) and mixed at 290 ℃ for 2 minutes and melted completely. Fifty seven point twenty grams (57.20 g) of Boron nitride (BN： product name is PT110， particle size is 40 μm， supplied from Momentive) were added to the melted resin and mixed at 290℃ for 20 minutes. The rotor speed for mixing was 50 rpm. The mixture (composite A-1) was collected and used as thermal conductive but electric insulating “sea” phase.

Expanded graphite (40.04 g， product name is C-THERM 011， particle size is from 20 to 30 micrometer， supplied from Timcal) was incorporated into 45.63 g of polyphenilene sulfide (PPS： supplied from SiChuan Deyang Chemical) by mixing with Haake (Polylab brand) same as above. The rotor speed was 50 rpm. The mixture (composite B-1) was collected and used as electric insulating “island” phase.

Seventeen point sixteen grams (17.16 g) of Composite B-1 were incorporated into 69.47 g of Composite A-1 bY mixing with Haake mixer at 290℃ for 5 minutes. The rotor speed for mixing composite B-1 and composite A-1 was 30 rpm. The mixture was collected and placed in a mold and compressed at 290℃ into a plate with a thickness of 2 mm. Then， the molded sample was cooled at room temperature. Thermal conductivity and volume resistivity was analyzed. Thermal conductivity for in-plane and through-plane direction was 11.6 and 3.1 W/mK respectively. Volume resistance was 2.15*10¹⁵ Ω·cm.

Analysis

1.Thermal conductivity

The thermal diffusivity α (mm²/s) of the samples was determined in through-plane direction of plates with Netzsch Nanoflash LFA 447 instrument， conforming to ASTM D1461-01. The experimental parameters used to collect the data were： Temperature 25 ℃， sample diameter 12.67 mm. A laser light absorbing spray was applied to surfaces of disk-shaped samples， so that the disk-shaped samples ware dried. Four flash shots were conducted and then the α average and Std. Dev. was obtained. The density ρ (g/cm³) of the samples at room temperature was measured by hydrostatic weighing， which uses the displacement of water due to a submerged object to determine the density of the object. The heat capacity Cp (J/g C) at 25 ℃ of the samples was determined by DSC (DSC-Q2000) according to ASTM E1269-11 Standard Test Method for Determining Specific Heat Capacity by Differential Scanning Calorimetry. The thermal conductivity (W/m·K) was calculated according to the following equation： TC＝α*ρ*Cp

2.Electrical properties

Volume/Surface resistivity of the cured sample was measured using 6517B Electrometer/High Resistance Meter， Keithley Instruments， Inc. The sample was clamped by electrode fixture (8009 Resistivity Test Fixture) ， then the volume /surface resistivity can be automatically measured according to ASTM D257-07.

Inventive Example 2

BN (66.00g) was incorporated into 22.80g of Nylon 66 (Zytel 101 F) the same process as disclosed in Inventive Example 1. The mixture (composite A-2) was collected and used as thermal conductive but electric insulating “sea” phase.

Thirty four point fifty eight grams (34.58 g) of expanded graphite were incorporated into 45.63g of PPS the same process as disclosed in Inventive Example 1. The mixture (composite B-2) was collected and used as electric insulating “island” phase.

Composite B-2 (26.95 g) was incorporated into Composite A-2 (57.72 g) the same process as disclosed in Inventive Example 1. The mixing speed was 30 rpm. A molded sample was formed same as Example 1. Thermal conductivity for in-plane and through-plane direction is 14.9 and 3.6 W/mK. Volume resistance of composite C is measured to be 3.3*10¹³ Ω·cm. The element mapping is conducted by using a field emission scanning electron microscopy (FESEM) ， equipped with energy-dispersive spectroscopy (EDS) analyze to acquire an element mapping image with accelerate voltage of 20KV. From element mapping of the sample， BN was located in Nylon 66 phase and graphite was located in PPS phase.

Inventive Example 3

BN (80.08 g) was incorporated into 21.06 g of PPS the same process as disclosed in Inventive Example 1. The mixture (composite A-3) was used as thermal conductive but electric insulating “sea” phase.

Expanded graphite (49.40 g) was incorporated into 29.64 g of Nylon 66 the same process as disclosed in Inventive Example 1. The mixture (composite B-3) was used as electric insulating “island” phase.

Composite B-3 (27.66 g) was incorporated into 65.74 g of Composite A-3 the same process as disclosed in Inventive Example 1. The mixing speed was 30 rpm. A molded sample was formed same as Example 1. Thermal conductivity for in-plane and through-plane direction is 15.2 and 2.7 W/mK respectively. Volume resistance of composite C is measured as 1.76*10¹² Ω·cm. From SEM observation of cross section of the sample， clearly phase separation between PPS phase and Nylon 66 phase was observed. From the element mapping of the sample， BN was located in PPS phase and graphite was located in Nylon phase.

Comparative Example 1

BN (45.76 g) and graphite (8.02 g) were incorporated into the blends of 23.71 g of Nylon 66 and 9.14 g of PPS by mixing with Haake (Polylab brand) at 50 rpm speed at 290℃. A cured sample was formed the same process as of Inventive Example 1. Thermal conductivity for through-plane direction is 2.9 W/mK. Volume resistance of composite is measured less than 1000 Ω·cm.

Comparative Example 2

BN (42.90 g) and graphite (11.62 g) were incorporated into the blends of 14.28 g of Nylon 66 and 15.33 g of PPS by mixing with Haake (Polylab brand) at 50 rpm speed at 290℃. A cured sample was formed the same process as of Inventive Example 1. Thermal conductivity for through-plane direction is 3.5 W/mK. Volume resistance of composite is measured less than 1000 Ω·cm.

Formulation was summarized in Table 1 and 2， the results was shown in Table 3.

Table 1 Formulation of Inventive Examples (volume ％)

Table 2 Formulation of Comparative Examples (volume ％)

Table 3 Thermal conductivity and electrical conductivity

Claims

A composition comprising

(a) a continuous phase comprising a first resin and at least one thermally conductive， electrically insulative filler and

(b) a discontinuous phase comprising a second resin and at least one thermally conductive， electrically conductive filler，

wherein the continuous phase surrounds discrete domains of the discontinuous phase.
The composition of claim 1， wherein the thermal conductive， electrical insulative filler is selected from zinc oxide， magnesia， silicon oxide， silicon carbide， aluminium nitride， boron nitride and almina.
The composition of claims 1 or 2， wherein the thermal conductive， electrical conductive filler is selected from graphite， graphene and metal particle.
The composition any of claims 1 to 3， wherein the ratio by volume of the first resin/the second resin is from 99/1 to 60/40.
The composition any of claims 1 to 4， wherein the melting point of the first resin is lower than the one of the second resin.
The composition any of claims 1 to 5， wherein the viscosity of the first resin is lower than the one of the second resin measured at the processed temperature of the composition.
The composition any of claims 1 to 6， wherein the content of the thermal conductive， electrical insulative filler in the continuous phase is from 20 to 70％ by volume based on the total volume of the continuous phase.
The composition any of claims 1 to 7， wherein the content of the thermal conductive， electrical conductive filler in the discontinuous phase is from 20 to 80％ by volume based on the total volume of the discontinuous phase.
The composition any of claims 1 to 8， wherein the dispersion size of the discontinuous phase in the composition is from 10 to 500 micro meter.
A method to prepare the composition of any of claims 1 to 9， comprising the steps of (a) preparing a first resin mixture comprising the first resin and at least one thermal conductive， electrical insulative filler and a second resin mixture comprising the second resin and at least one thermal conductive， electrical conductive filler separately， and (b) mixing the first resin mixture and the second resin mixture under the condition for the second resin mixture which phase separates with the first resin mixture and forms discrete domains of a discontinuous phase surrounded by the first resin mixture.
The method of claim 10， wherein the mixing the first resin mixture and the second resin mixture is conducted at the temperature higher than melting point of resin A and lower than the melting point of resin B.
A polymer composite material formed from the composition any of claims 1 to 9.
The polymer composite material of claim 12， wherein the electrical resistivity of the material is 1Xl0¹²Ω·cm or more.
The polymer composite material of claim 12， wherein the thermal conductivity of the material is 10W/mK or more.
An article comprising a heat source and an electrically insulating thermal management component located in proximity to the heart source， wherein the thermal management component comprises the polymer composite material any of claims 12 to 14.