Thermal interface materials comprising silane coupling agents to reduce stiffness of materials and / or to reduce
By adding silane coupling agents to thermal interface materials, the problems of thermal management and electromagnetic interference of electronic components are solved, achieving high thermal conductivity and low material migration and diffusion, thus ensuring the stability and signal integrity of electronic devices.
Patent Information
- Application Number
- CN202510941736.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-07-17
- Filing Date
- 2025-07-09
- Publication Date
- 2026-01-20
AI Technical Summary
In the prior art, the heat and electromagnetic interference generated by electronic components during operation have not been effectively managed, resulting in decreased equipment efficiency and signal interference. Furthermore, the hardness of the thermal interface material and the problems of material migration and diffusion have not been effectively solved.
By employing a composite containing a silane coupling agent, at least 0.5% by weight of the silane coupling agent is added to the matrix to reduce material hardness, improve recovery rate and reduce material diffusion, enhance adhesion and improve dispersibility, thus forming a material with efficient thermal management and reduced electromagnetic interference.
It achieves high recovery rate and low material migration and diffusion under low compressive force, improves thermal conductivity, reduces electromagnetic interference, and ensures stable operation of electronic equipment and signal integrity.
Smart Images
Figure CN121362456A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present disclosure relates to thermal interface materials (generally, composites) including silane coupling agents for reducing material hardness and / or for reducing diffusion of materials (if any) migrating therefrom (e.g., reducing oil bleed-out diffusion, etc.). The present disclosure also relates to methods of reducing material hardness and / or reducing diffusion of materials (if any) migrating from composites used for managing heat and / or electromagnetic interference (EMI). The composites can include thermal management and / or electromagnetic interference (EMI) mitigation materials such as thermal interface materials (TIMs) (e.g., low oil bleed-out and high recovery rate thermal pads, etc.), EMI absorbers, thermally conductive EMI absorbers, electrically conductive elastomers (ECEs), electrically conductive composites, combinations thereof, etc. BACKGROUND
[0002] This section provides background information relating to the present disclosure and is not necessarily prior art.
[0003] Electrical components such as semiconductors, integrated circuit packages, transistors, etc. generally have pre-designed temperatures at which the electrical components operate best. Ideally, the pre-designed temperatures are close to the temperature of the surrounding air. However, the operation of electrical components generates heat. If the heat is not removed, the electrical components can operate at temperatures significantly higher than their normal or desired operating temperatures. Such excessively high temperatures can adversely affect the operating characteristics of the electrical components and the operation of related devices.
[0004] To avoid or at least reduce adverse operating characteristics from heat generation, the heat should be removed, for example, by conducting the heat from the operating electrical components to a heat sink. The heat sink can then be cooled by conventional convection and / or radiation techniques. During conduction, heat can be transferred from the operating electrical components to the heat sink through direct surface contact between the electrical components and the heat sink and / or through contact of the electrical components and the heat sink surfaces via an intermediate medium or thermal interface material (TIM). Thermal interface materials can be used to fill the gaps between the heat transfer surfaces in order to increase the efficiency of heat transfer as compared to filling the gaps with air, which is a relatively poor thermal conductor.
[0005] Additionally, a common problem in the operation of electronic devices is the generation of electromagnetic radiation within the electronic circuitry of the device. This radiation can cause electromagnetic interference (EMI) or radio frequency interference (RFI) that can interfere with the operation of other electronic devices within a certain distance. Without adequate shielding, EMI / RFI interference can cause degradation or complete loss of important signals, rendering the electronic device inefficient or inoperable.
[0006] The term "EMI" as used herein shall be taken to include and refer to EMI emissions and RFI emissions generally, and the term "electromagnetic" shall be taken to include and refer to electromagnetic frequencies and radio frequencies from both external and internal sources generally. Thus, the term shielding (as used herein) broadly includes and refers to mitigating (or limiting) EMI and / or RFI, such as by absorbing, reflecting, blocking, and / or redirecting energy or some combination thereof, so that the EMI and / or RFI, for example, no longer interferes with government compliance and / or internal functionality of an electronic component system. SUMMARY
[0007] In one aspect, the present disclosure provides a composite for managing heat and / or electromagnetic interference (EMI), the composite comprising a matrix, one or more functional fillers within the matrix, and a silane coupling agent within the matrix, wherein:
[0008] the composite comprises at least about 0.5 wt% of the silane coupling agent, based on the total weight of the composite; and / or
[0009] the composite comprises the silane coupling agent in a sufficient amount to reduce the hardness of the composite such that the composite is configured to have a high recovery rate and a low compression force and / or to reduce the diffusion of material, if any, that migrates from the composite.
[0010] In another aspect, the present disclosure provides a method of reducing hardness and / or reducing the diffusion of material, if any, that migrates from a composite for managing heat and / or electromagnetic interference (EMI), the method comprising adding a silane coupling agent to the composite such that the composite comprises at least about 0.5 wt% of the silane coupling agent, based on the total weight of the composite. BRIEF DESCRIPTION OF DRAWINGS
[0011] The drawings described herein are for illustrative purposes only of selected embodiments and are not all possible implementations, and are not intended to limit the scope of the present disclosure.
[0012] Figure 1 and 2 are photographs of exemplary thermal interface materials (composites broadly) according to exemplary embodiments that include a silane coupling agent for reducing material hardness and reducing the diffusion of material, if any, that migrates therefrom. As shown in Figure 1 and Figure 2 there was no bleed out of oil from the thermal interface material at day 1 ( Figure 1 ) and day 7 ( Figure 2 ). DETAILED DESCRIPTION
[0013] Example embodiments now will be described more fully hereinafter with reference to the accompanying drawings.
[0014] As recognized herein, a thermal pad (broadly, thermal interface material) having low oil bleed-out, high recovery rate, and low compression force would be advantageous. Accordingly, disclosed herein are thermal interface materials (broadly, composites) having low oil bleed-out, high recovery rate at low compression force, and high thermal conductivity (e.g., at least 1 Watt per meter per Kelvin (W / mK), 2 W / mK, 3 W / mK, 4 W / mK, 5 W / mK, greater than 5 W / mK, etc.). The thermal interface materials (e.g., thermal pads, etc.) disclosed herein can be advantageously used along an interface between a heat sink (broadly, heat dissipation / heat spreading structure) and an integrated circuit (IC) (broadly, heat source).
[0015] In recognition of the foregoing, disclosed and / or developed herein are exemplary embodiments of thermal interface materials (broadly, composites) that include a silane coupling agent for reducing a material hardness and / or for reducing diffusion of a material (if any) that migrates therefrom (e.g., reducing oil bleed-out diffusion, etc.). Also disclosed are exemplary methods of reducing a material hardness and / or reducing diffusion of a material (if any) that migrates from a composite that can be used to manage heat and / or electromagnetic interference (EMI). The composites can include thermal management and / or electromagnetic interference (EMI) mitigation materials such as thermal interface materials (TIMs) (e.g., low oil bleed-out and high recovery rate thermal pads, etc.), EMI absorbers, thermally conductive EMI absorbers, electrically conductive elastomers (ECEs), electrically conductive composites, combinations thereof, etc.
[0016] Disclosed are exemplary composites that can be used to manage heat and / or electromagnetic interference (EMI). In exemplary embodiments, the composites include a matrix, one or more functional fillers within the matrix, and a silane coupling agent within the matrix. The composites can include at least about 0.5 wt% of the silane coupling agent based on a total weight of the composite. Additionally or alternatively, the composites can include a sufficient amount (e.g., at least about 0.5 wt% or more, etc.) of the silane coupling agent to reduce a hardness of the composite, to configure the composite to have a high recovery rate and a low compression force, and / or to reduce diffusion of a material (if any) that migrates from the composite.
[0017] In exemplary embodiments, the silane coupling agent is operable to wet a surface of the particles to facilitate mixing with the silicone resin (broadly, matrix) and to form bonds between the resin and the different particles. The amount of the silicone coupling agent is preferably high or increased enough to reduce a material hardness of the composite such that the composite has a high recovery rate at a low compression force. The amount of the silicone coupling agent is also preferably high or increased enough to ensure that unreacted polymers are bound to the surface of the particles, thereby avoiding unreacted polymers from readily diffusing out of and migrating from the composite.
[0018] In exemplary embodiments, the silane coupling agent preferably facilitates adhesion between the different materials of the composite by forming a durable bond between the organic and inorganic materials. The silane coupling agent preferably reacts with the surface of the functional filler and the matrix resin of the composite and forms an interfacial layer between them, which can transfer stress, thereby enhancing the bond strength between them and improving the performance of the composite. The silane coupling agent can also preferably improve the dispersibility during mixing of the resin and the functional filler, and improve the mechanical strength, water and heat resistance, transparency, adhesion, and other properties of the composite.
[0019] In exemplary embodiments, the composite includes at least about 0.5 wt% but no more than about 1 wt% of the silane coupling agent. And the composite includes at least about 0.1 vol% of the silane coupling agent. The composite can include at least about 0.1 vol% but no more than about 0.6 vol% of the silane coupling agent. For example, the composite can include about 0.93 wt% and about 0.3 vol% of the silane coupling agent.
[0020] In exemplary embodiments, the silane coupling agent includes hexadecyltrimethoxysilane or trimethoxyhexadecylsilane, which has a linear formula of H3C(CH2)i5Si(OCH3)3. In such exemplary embodiments, the composite includes at least about 0.5 wt% but no more than about 1 wt% (e.g., about 0.93 wt%, etc.) of the hexadecyltrimethoxysilane. For example, the composite can include about 0.93 wt% and about 0.3 vol% of the hexadecyltrimethoxysilane. The molecular weight of the hexadecyltrimethoxysilane is 346.62, and the chemical formula is as follows.
[0021]
[0022] In other exemplary embodiments, the silane coupling agent includes doecyltrimethoxysilane. In such exemplary embodiments, the composite includes at least about 0.5 wt% but no more than about 1 wt% (e.g., about 0.93 wt%, etc.) of the doecyltrimethoxysilane. For example, the composite can include about 0.93 wt% and about 0.3 vol% of the doecyltrimethoxysilane.
[0023] In exemplary embodiments, the composite includes a sufficient amount (e.g., at least about 0.5 wt% or more, etc.) of the silane coupling agent to ensure that the unreacted polymer of the composite bonds with the particle surface of the one or more functional filler particles, thereby reducing or avoiding diffusion of the unreacted polymer (if any) that migrates from the composite.
[0024] In example embodiments, the matrix comprises a silicone resin matrix. And the composite comprises a sufficient amount (e.g., at least about 0.5 wt% or more, etc.) of silane coupling agent for improving dispersion during mixing of one or more functional fillers within the silicone resin matrix, for facilitating adhesion between the silicone resin and the one or more functional fillers, and for ensuring that unreacted polymer binds to the surface of the particles of the one or more functional fillers to avoid easy diffusion of the unreacted polymer, if any, out, thereby reducing silicone oil exudation from the composite, and making the composite substantially or fully usable without silicone oil migrating or being released beyond the confines of the composite.
[0025] In example embodiments, the composite comprises a sufficient amount (e.g., at least about 0.5 wt% or more, etc.) of silane coupling agent such that the composite is configured to have a reduced silicone oil exudation over time from the composite of less than 2%, thereby making the composite substantially or fully usable without silicone oil migrating or being released beyond the confines of the composite.
[0026] In example embodiments, the composite comprises a sufficient amount (e.g., at least about 0.5 wt% or more, etc.) of silane coupling agent such that the composite is configured to have a reduced silicone oil exudation over time of 1% or less, as determined by the HT method. As background, the HT method for determining silicone oil exudation over time generally includes a weight loss test method. The test procedure is as follows:
[0027] • Select appropriate sample and sample size based on product specification, cut product into 1 square inch sample with round die, weigh the cut sample and record initial weight W0;
[0028] • Cover both sides of the sample with 1 layer of glass fiber;
[0029] • Cover both sides of the sample with 3 layers of filter paper;
[0030] • Place sample into oil exudation fixture, select appropriate spacers to control sample compression, assemble fixture with power screwdriver;
[0031] • Place fixture into 125°C oven for set time;
[0032] • Remove sample at end of bake, weigh and record final weight W1; and
[0033] • Oil exudation weight loss test formula is:
[0034] Oil exudation weight loss = (Initial weight W0 - Final weight W1) / Initial weight W0 * 100%.
[0035] In exemplary embodiments, the composite comprises silane coupling agent in an amount sufficient (e.g., at least about 0.5 wt.% or more, etc.) such that the composite is configured to have a reduced silicone oil bleed over time of about 10% at day 12, as determined by the rough blotting paper method. As background, the rough blotting method for determining silicone oil bleed over time is primarily a diameter test as follows:
[0036] • Select the appropriate sample and sample size based on product specification, cut the product into square inch samples by die cutting, place the samples on blotting paper on the rough side;
[0037] • Place the sample and blotting paper into the fixture and place shims to control sample compression;
[0038] • Place a plastic plate on top of the fixture and assemble with a power screwdriver;
[0039] • Place the fixture into the oven and bake at 125°C for the specified time;
[0040] • Remove the fixture after the bake is complete;
[0041] • Measure the diameter of the sample and the maximum oil diameter using a ruler or gauge; and
[0042] • Oil bleed area ratio calculation method:
[0043] Oil bleed % = (Oil bleed marker diameter - Sample diameter after bake) / Sample diameter after bake * 100%.
[0044] In exemplary embodiments, the composite has a high thermal conductivity of at least 1 Watt per meter per Kelvin (W / mK) as determined by a hot disk thermal constant analyzer. For example, the composite can have a thermal conductivity of 1 W / mK, 2 W / mK, 3 W / mK, 4 W / mK, 5 W / mK, greater than 5 W / mK, etc. To determine the thermal conductivity, a hot disk instrument can be used which measures thermal conductivity, thermal diffusivity, and specific heat capacity using a transient plane source method. As background, this technique is covered under ISO 22007-2:2008; Part 2 standard. The technique utilizes a planar sensor and a special mathematical model describing the thermal conductivity combined with electronics enabling the method for measuring heat transport properties. It covers a thermal conductivity range of typically 0.01 to 500 W / m / K. The transient plane source technique typically employs two sample halves that hold the sensor. The method can also be used in a single-sided configuration. The technique is versatile and fast, covering measurements of solids, pastes, thin films, and liquids. It can evaluate isotropic and anisotropic materials. The planar sensor consists of a continuous double helix of electrically conducting nickel metal, etched from a thin foil. The nickel helix is located between two thin layers of polyimide film, Kapton. During the measurement, a constant electrical effect is passed through the conducting helix, increasing the sensor temperature. The generated heat dissipates into the sample on both sides of the sensor at a rate that depends on the heat transport properties of the material. By recording the temperature response in the sensor versus time, the thermal conductivity, thermal diffusivity, and specific heat capacity of the material can be calculated.
[0045] In exemplary embodiments, the composite comprises one or more functional fillers comprising one or more of: a thermally conductive filler; an electrically conductive filler; an electromagnetic wave absorbing filler; a dielectric absorbing filler; and a filler having two or more of the properties of thermally conductive, electrically conductive, dielectric absorbing, and electromagnetic wave absorbing.
[0046] In an example embodiment, the composite comprises one or more functional fillers comprising one or more alumina fillers within a matrix, such that the composite comprises at least 90 weight percent of the one or more alumina fillers. And the composite has a thermal conductivity of at least 1 watt per meter per Kelvin. The at least one or more alumina fillers within the matrix can comprise at least three different alumina fillers within the matrix. For example, the at least three different alumina fillers can comprise a first alumina filler having a D50 average particle size of about 2 microns, a second alumina filler having a D50 average particle size of about 10 microns, and a third alumina filler having a D50 average particle size of about 70 microns. Continuing with this example, the first alumina filler can comprise alumina spherical particles having a D50 average particle size of about 2 microns. The second alumina filler can comprise alumina spherical particles having a D50 average particle size of about 10 microns. The third alumina filler comprises alumina spherical particles having a D50 average particle size of about 70 microns. As background, the D50 of a particle size distribution is also referred to as the median diameter or median of the particle size distribution, and is the particle size value at 50% in the cumulative distribution.
[0047] The composite can comprise about 93.3 weight percent of the first, second, and third alumina fillers, based on the total weight of the composite. For example, the composite can comprise about 23.30 weight percent of the first alumina filler, about 30 weight percent of the second alumina filler; and about 40 weight percent of the third alumina filler. The composite can comprise about 16 volume percent to about 22 volume percent of the first alumina filler, about 20 volume percent to about 28 volume percent of the second alumina filler, and about 28 volume percent to about 36 volume percent of the third alumina filler. In one example embodiment, the composite comprises about 19 volume percent of the first alumina filler, about 24 volume percent of the second alumina filler, and about 32 volume percent of the third alumina filler.
[0048] In an example embodiment, the composite is configured to have a recovery of greater than 30% for a 2.5 millimeter thickness, a peak force of less than 100 pounds per square inch (PSI) for 50% compression, and a residual force of less than 20 PSI for 50% compression.
[0049] In an example embodiment, the composite is configured to have a reduced silicone oil exudation rate over time (determined by the HT method) of less than 2%, a deflection of greater than 50% at 30 pounds per square inch (PSI) for a 2 millimeter thickness, a thermal resistance of less than 0.45 at 10 PSI for a 1 millimeter thickness, a hardness of less than 45 Shore 00, and a recovery of greater than 30% for a 2.5 millimeter thickness, a peak force of less than 100 PSI for 50% compression, and a residual force of less than 20 PSI for 50% compression.
[0050] In example embodiments, the composite is configured to have a thermal conductivity of at least 3.4 Watts per meter per Kelvin as determined by a hot disk thermal constant analyzer; a reduced silicone oil bleed over time of 1% or less (as determined by the HT method) and / or about 10% at day 12 (as determined by the coarse blotter method); a flex modulus of at least 61% for a 2 mm thickness at 30 PSI; a thermal resistance of 0.318 or less for a 1 millimeter thickness at 10 PSI; a hardness of 31 Shore 00 or less; and a recovery of at least 46% for a 2.5 millimeter thickness, where the peak force is 25 PSI or less for 50% compression and the residual force is 5.6 PSI or less for 50% compression.
[0051] In example embodiments, the composite includes a crosslinked thermally conductive gap pad having a thermal conductivity of at least 3.4 Watts per meter per Kelvin as determined by a hot disk thermal constant analyzer and an oil bleed of about 10% at day 12 as determined by the coarse blotter method.
[0052] In example embodiments, the matrix includes: a first silicone vinyl oil having a first viscosity and a first molarity; and a second silicone vinyl oil having a second viscosity higher than the first viscosity and a second molarity lower than the first molarity. For example, the composite can include: about 2.47 wt% of a silicone vinyl oil having a viscosity of 1000 centistokes (cSt) and a molarity of 0.11 millimoles per gram (mmol / g); and about 1.67 wt% of a silicone vinyl oil having a viscosity of 5000 centistokes (cSt) and a molarity of 0.06 millimoles per gram (mmol / g).
[0053] In example embodiments, the composite includes a crosslinking agent, a chain extender, a catalyst, and an inhibitor. For example, the composite can include about 0.47 wt% of a crosslinking agent, about 1.13 wt% of a chain extender, about 0.01 wt% of a catalyst, and about 0.10 wt% of an inhibitor. The crosslinking agent can include polysiloxanes di-Me Me hydrogen. The chain extender can include a dimethyl hydrogen terminated PDMS. The catalyst can include a platinum catalyst. And the inhibitor can include a silicone inhibitor.
[0054] In one example embodiment, the composite comprises: about 23.3 wt% of a first alumina filler comprising spherical alumina particles having an average particle size D50 of 2 microns; about 30 wt% of a second alumina filler comprising spherical alumina particles having an average particle size D50 of 10 microns; and about 40 wt% of a third alumina filler comprising spherical alumina particles having a D50 average particle size of 70 microns. The composite includes about 23.30 wt% of the first alumina filler, about 30 wt% of the second alumina filler, and about 40 wt% of the third alumina filler. The composite is configured to have: a thermal conductivity of at least 3.4 Watts per meter per Kelvin as determined by a hot disk thermal constant analyzer; a reduced silicone oil bleed over time of 1% or less (as determined by the HT method) and / or about 10% at day 12 (as determined by the coarse blotter method); a deflection of at least 61% for a 2 mm thickness at 30 PSI; a thermal resistance of 0.318 or less for a 1 millimeter thickness at 10 PSI; a hardness of 31 Shore 00 or less; and a recovery of at least 46% for a 2.5 millimeter thickness, where the peak force is 25 PSI or less for 50% compression, and the residual force is 5.6 PSI or less for 50% compression. Continuing the example, the composite includes: about 2.47 wt% of a silicone vinyl oil having a viscosity of 1000 centistokes (cSt) and a molar concentration of 0.11 millimoles per gram (mmol / g); about 1.67 wt% of a silicone vinyl oil having a viscosity of 5000 centistokes (cSt) and a molar concentration of 0.06 millimoles per gram (mmol / g); about 0.47 wt% of a crosslinker; about 1.13 wt% of a chain extender; about 0.93 wt% of a silane coupling agent; about 0.01 wt% of a catalyst; and about 0.10 wt% of an inhibitor.
[0055] By way of example only, the following table includes comparative properties of two conventional thermal pad composites, A and B, and a composite, C, of an example embodiment. Composite C includes at least about 0.5 wt% of a silane coupling agent as disclosed herein. Conventional thermal pad composite A includes 15 to 25 wt% of a silicone resin, 0.02 to 0.1 wt% of an additive, and 70 to 85 wt% of alumina. Conventional thermal pad composite B includes 5 to 10 wt% of a silicone resin, 0.02 to 0.2 wt% of an additive, and 85 to 95 wt% of alumina.
[0056] As shown in Table 1 below, of the three composites A, B, and C, exemplary composite C has the highest thermal conductivity of 3.6 W / mK, the lowest oil bleed, and the highest recovery of 45%. Conventional thermal pad composite A has the lowest thermal conductivity of 1 W / mK. Generally, higher thermal conductivity will be more beneficial for conducting heat. But other properties are also important, including flex, compression force, oil bleed, recovery, volatility, etc. As recognized herein, it is desirable to provide a material that has high flex, low compression force, low or no oil bleed, high recovery. And as further recognized herein, adding more filler loading to increase thermal conductivity can increase the material hardness such that the material is too stiff to flex and has high compression force. Composites A and C have similar flex to compression force curves, but composite C has a thermal conductivity of 3.6 W / mK, which is significantly higher than the 1 W / mK thermal conductivity of conventional composite A. At the same compression force, the flex of composites A and C are about equal and higher than the flex of composite B.
[0057]
[0058] In exemplary embodiments, the thermal interface material comprises a composite as disclosed herein. The thermal interface material includes a thermal pad, a thermal gap filler, a phase change thermal interface material, a dispensable material, a bulk putty, a thermal grease, a thermal interface material sheet, etc. For example, the thermal interface material can include a thermal pad having a shape of a rectangle, a triangle, a circle, an oval, a polygon, etc. The thermal interface material can include a sheet having a shape of a rectangle, a triangle, a circle, an oval, a polygon, etc. The thermal interface material can include a die cut portion having a shape of a rectangle, a triangle, a circle, an oval, a polygon, etc.
[0059] In example embodiments, the composite includes a thermally conductive filler and an EMI absorbing filler in a matrix, such that the composite includes a multifunctional EMI absorber having a first functionality of EMI mitigation and a second functionality of thermal management, or vice versa. By way of example, the filler can include one or more of a functional nanoparticle, an electrically conductive filler, a thermally conductive filler, an EMI or microwave absorbing filler, a magnetic filler, a coated filler, combinations thereof, and the like. The filler can be added and mixed into a bulk material including a matrix material, thereby providing a mixture of the filler and the base or matrix material. Example fillers include carbon black, boron nitride, nickel cobalt, carbonyl iron, siliconized iron, iron particles, iron chromium compounds, silver, an alloy containing 85% iron, 9.5% silicon, and 5.5% aluminum, an alloy containing about 20% iron and 80% nickel, ferrites, magnetic alloys, magnetic powders, magnetic flakes, magnetic particles, nickel-based alloys and powders, chromium alloys, oxides, copper, zinc oxide, aluminum oxide, graphite, ceramics, silicon carbide, manganese zinc, glass fibers, carbon nanotubes (e.g., single-walled carbon nanotubes, multi-walled carbon nanotubes, and / or carbon nanostructures, etc.), combinations thereof, and the like. The filler can include one or more of a particle, a spheroid, a microsphere, an ellipsoid, an irregular spheroid, a strand, a flake, a powder, a nanotube, and / or combinations of any or all of these shapes. Further, example embodiments can also include different grades (e.g., different sizes, different purities, different shapes, etc.) of the same (or different) fillers.
[0060] In example embodiments, the composite includes a mat having a rectangular, triangular, oval, circular, or polygonal shape. Alternatively, the composite includes a sheet having a rectangular, triangular, oval, circular, or polygonal shape. Alternatively, the composite includes a die-cut part having a rectangular, triangular, oval, circular, or polygonal shape.
[0061] In example embodiments, the composite is a thermal interface material, an EMI absorber, a thermally conductive absorber, an electrically conductive elastomer, an electrically conductive composite, or a combination of two or more thereof. For example, the composite can be a thermal phase change material, a thermal putty, a thermal paste, a dispensable thermal interface material, and / or a thermal gap filler pad.
[0062] In example embodiments, the composite includes one or more functional fillers including one or more of zinc oxide, aluminum oxide, boron nitride, aluminum, silicon carbide, and / or aluminum nitride.
[0063] In example embodiments, an apparatus or system includes a composite as disclosed herein for managing thermal properties of the apparatus or system.
[0064] Also disclosed are exemplary methods of reducing hardness and / or reducing diffusion of material, if any, migrating from a composite for managing heat and / or electromagnetic interference (EMI). In exemplary embodiments, the method includes adding a silane coupling agent to the composite such that the composite includes at least about 0.5 wt% of the silane coupling agent based on the total weight of the composite.
[0065] In exemplary embodiments, the method includes adding a silane coupling agent (e.g., hexadecyltrimethoxysilane, dodecyltrimethoxysilane, etc.) to the composite such that the composite includes at least about 0.5 wt% but no more than about 1 wt% of the silane coupling agent and / or adding a silane coupling agent to the composite such that the composite includes at least about 0.1 vol% of the silane coupling agent.
[0066] In exemplary embodiments, the method includes adding a silane coupling agent to the composite such that the composite includes at least about 0.1 vol% but no more than about 0.6 vol% of the silane coupling agent.
[0067] In exemplary embodiments, the method includes adding a silane coupling agent to the composite such that the composite includes about 0.93 wt% of the silane coupling agent and about 0.3 vol wt% of the silane coupling agent.
[0068] In exemplary embodiments, the method configures the composite to have a high recovery rate and a low compression force.
[0069] In exemplary embodiments, the method includes adding a sufficient amount of the silane coupling agent to ensure that unreacted polymer of the composite binds to the particle surface of the one or more functional filler particles of the composite, thereby reducing or avoiding diffusion of unreacted polymer, if any, migrating from the composite.
[0070] In exemplary embodiments, the composite includes a silicone resin matrix and one or more functional filler particles within the silicone resin matrix. And the method includes adding a sufficient amount of the silane coupling agent to improve dispersion during mixing more functional filler particles within the silicone resin matrix. To facilitate adhesion between the silicone resin and the one or more functional filler particles, and to ensure that unreacted polymer binds to the particle surface of the one or more functional filler particles to avoid unreacted polymer to diffuse out easily, thereby reducing the exudation rate of silicone oil exuding from the composite, making the composite substantially or completely usable without silicone oil migrating or releasing beyond the scope of the composite.
[0071] Furthermore, the example embodiments disclosed herein can be used in a wide range of industries (e.g., automotive, consumer, industrial, datacom / telecom, aerospace / defense, etc.) and a wide range of applications (e.g., automotive electronics, automotive advanced driver assistance systems (ADAS), automotive powertrain / electronic control units (ECUs), automotive infotainment, routers, hard drives, solid state drives, wireless infrastructure, drones / satellites, gaming systems, smart home devices, laptops / tablets / portable devices, etc.).
[0072] In example embodiments, an electronic device includes a heat source and a composite disclosed herein that can be used as a thermal interface material (e.g., a thermal pad, a thermal gap filler, a phase change thermal interface material, a dispensable material, a bulk grease, a thermal paste, and / or a thermal interface material sheet, etc.). The composite is positioned relative to the heat source for establishing at least a portion of a thermally conductive heat path from the heat source through the composite. The composite can also be configured to be EMI absorbing and / or electrically conductive such that the composite is further operable to mitigate and / or manage EMI within the electronic device.
[0073] In example embodiments, an electronic device includes a heat source, a heat removal / dissipation structure, and a composite as disclosed herein that can be used as a thermal interface material (e.g., a thermal pad, a thermal gap filler, a phase change thermal interface material, a dispensable material, a bulk grease, a thermal paste, and / or a thermal interface material sheet, etc.). The composite is positioned relative to the heat source and the heat removal / dissipation structure for establishing at least a portion of a thermally conductive heat path between the heat source and the heat removal / dissipation structure. The composite can also be configured to be EMI absorbing and / or electrically conductive such that the composite is further operable to mitigate and / or manage EMI within the electronic device.
[0074] In example embodiments, an electronic device includes a heat source, a board level shield, and a composite disclosed herein that can be used as a thermal interface material (e.g., a thermal pad, a thermal gap filler, a phase change thermal interface material, a dispensable material, a bulk grease, a thermal paste, and / or a thermal interface material sheet, etc.). The composite is positioned relative to the heat source and the board level shield for establishing at least a portion of a thermally conductive heat path between the heat source and the board level shield. The composite can also be configured to be EMI absorbing and / or electrically conductive such that the composite is further operable to mitigate and / or manage EMI within the electronic device.
[0075] In example implementations, an electronic device includes a heat source, a board-level shield, a heat removal / dissipation structure, and first and second compounds that can be used as thermal interface materials (e.g., thermal pads, thermal gap fillers, phase change thermal interface materials, dispensable materials, bulk greases, thermal pastes, and / or thermal interface material sheets, etc.). The first compound is positioned relative to the heat source and the board-level shield for establishing at least a portion of a first thermal conduction path between the heat source and the board-level shield. The second compound is positioned relative to the board-level shield and the heat removal / dissipation structure for establishing at least a portion of a second thermal conduction path between the board-level shield and the heat removal / dissipation structure. The first and / or second compounds can also be configured to be EMI-absorbing and / or electrically conductive, such that the first and / or second compounds are also operable to mitigate and / or manage EMI within the electronic device.
[0076] In example implementations, an electronic device includes an integrated circuit, a board-level shield, a heat sink, and first and second compounds that can be used as thermal interface materials (e.g., thermal pads, thermal gap fillers, phase change thermal interface materials, dispensable materials, bulk greases, thermal pastes, and / or thermal interface material sheets, etc.). The first compound is positioned relative to the integrated circuit and the board-level shield for establishing at least a portion of a first thermal conduction path between the integrated circuit and the board-level shield. The second compound is positioned relative to the board-level shield and the heat sink for establishing at least a portion of a second thermal conduction path between the board-level shield and the heat sink. The first and / or second compounds can also be configured to be EMI-absorbing and / or electrically conductive, such that the first and / or second compounds are also operable to mitigate and / or manage EMI within the electronic device.
[0077] The example implementations disclosed herein can be used with a wide range of heat sources, electronic devices, and / or heat removal / dissipation structures or components (e.g., heat spreaders, heat sinks, heat pipes, vapor chambers, device housings, enclosures, or chassis, etc.) together. For example, the heat source can include one or more heat-generating components or devices, such as high-power integrated circuits (ICs), optical transceivers, 5G infrastructure equipment (e.g., base stations, small cells, smart poles, etc.), solid state drives (SSDs), memory in video cards, set-top boxes, televisions, gaming systems, automotive electronics for autonomous driving (ADAS) (e.g., radars, multi-domain controllers, cameras, etc.), CPUs, dies within underfill, semiconductor devices, flip-chip devices, graphics processing units (GPUs), digital signal processors (DSPs), multi-processor systems, integrated circuits (ICs), multi-core processors, etc. Generally, the heat source can include any component or device that has a higher temperature than the heat management and / or EMI mitigation material or otherwise provides or transfers heat to the heat management and / or EMI mitigation material, whether the heat is generated by the heat source or merely transferred through or via the heat source. Accordingly, aspects of the present disclosure should not be limited to use with any single type of heat source, electronic device, heat removal / dissipation structure, etc.
[0078] The example implementations are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of implementations of the present disclosure. Those skilled in the art will recognize that the example implementations can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In some example implementations, well-known processes, well-known device structures, and well-known technologies are not described in detail unless their
[0079] The particular dimensions, materials, and / or shapes disclosed herein are by way of example only and without limitation. The disclosure of particular values and particular ranges of values for a given parameter in this disclosure is not to be taken as an exclusion of other values and ranges of values for that parameter unless expressly excluded or otherwise specifically stated. Also, it is intended that any two particular values for a parameter that are recited can define endpoints for a range of values for that parameter (i.e., the disclosure of a first value and a second value for a given parameter can be interpreted as disclosing that the first and second values are the endpoints of a range of values for the parameter). For example, if a parameter X is exemplified herein as having a value A and also as having a value Z, it is contemplated that parameter X can have a range of values from about A to about Z. Similarly, it is contemplated that the disclosure of two or more value ranges for a parameter, whether such ranges are nested, overlapping, or distinct, includes all possible combinations of the ranges that can be derived from the disclosed ranges. For example, if a parameter X is exemplified herein as having a range 1-10 or 2-9 or 3-8, it is also contemplated that parameter X can have other value ranges including 1-9, 1-8, 1-3, 1-2, 2-10, 2-8, 2-3, 3-10, and 3-9.
[0080] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a," "an," and "the" can be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "has," "having," "including," and their variants are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and / or components but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order
[0081] When an element or layer is referred to as being "on," "engaged," "connected," or "coupled" to another element or layer, it can be directly on, engaged, connected, or coupled to the other element or layer, or intervening elements or layers can be present. In contrast, when an element is referred to as being "directly on," "directly engaged," "directly connected," or "directly coupled" to another element or layer, there are no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in the same fashion (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.
[0082] The term "about" when applied to a value indicates that the calculation or measurement is permitted to vary slightly (close to the accurate; approximate or reasonably close to the value; nearly) from the value. If the inaccuracy provided by "about" is not otherwise understood in the art for some reason, "about" as used herein indicates at least variation that can be caused by ordinary measurement methods or use of such parameters. For example, the terms "substantially," "approximately," and "about" can be used herein to mean within manufacturing tolerances. Whether or not modified by the term "about," the claims include equivalents of the recited numbers.
[0083] Although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms as used herein do not permit order, unless the context clearly indicates. As such, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the exemplary embodiments.
[0084] Spatially relative terms such as "in," "on," "under," "below," "lower," "above," "upper," and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms can be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "under" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
[0085] The foregoing description of implementations has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Independent elements of a particular implementation described herein can generally be interchanged with each other and with other independent elements of other implementations described herein, and implementation-specific descriptions are not intended to be exclusive or exhaustive. Same can be altered in many ways. Such alterations are not to be viewed as a departure from the scope of the disclosure, and all such modifications are intended to be included within the scope of the disclosure. Changes are intended to be construed as being within the scope of the disclosure.
[0086] Industrial Applicability
[0087] Composites according to the present disclosure can reduce material hardness and / or reduce diffusion of material, if any, migrating therefrom (e.g., reduce oil bleed-out diffusion, etc.). Methods according to the present disclosure can reduce material hardness and / or reduce diffusion of material, if any, migrating from composites that can be used to manage heat and / or electromagnetic interference (EMI).
Claims
1. A composite for managing heat and / or electromagnetic interference (EMI), the composite comprising a matrix, one or more functional fillers within the matrix, and a silane coupling agent within the matrix, wherein: the composite includes at least about 0.5 wt. % of the silane coupling agent, based on the total weight of the composite; and / or the composite includes a sufficient amount of the silane coupling agent to reduce the hardness of the composite such that the composite is configured to have a high recovery rate and a low compression force, and / or to reduce the diffusion of material migrating from the composite in the event of material migrating from the composite.
2. The complex of claim 1, wherein, the composite includes at least about 0.5 wt. % but no more than about 1 wt. % of the silane coupling agent.
3. The composite of any of the preceding claims, wherein, the composite includes at least about 0.1 vol. % of the silane coupling agent.
4. The composite of any of the preceding claims, wherein, the composite includes at least about 0.1 vol. % but no more than about 0.6 vol. % of the silane coupling agent.
5. The composite of any of the preceding claims, wherein, the composite includes about 0.93 wt. % of the silane coupling agent.
6. The composite of any of the preceding claims, wherein, the composite includes about 0.3 vol. wt. % of the silane coupling agent.
7. The composite of any of the preceding claims, wherein, the silane coupling agent includes hexadecyltrimethoxysilane.
8. The composite of any of the preceding claims, wherein, the composite includes a sufficient amount of the silane coupling agent to ensure that unreacted polymer of the composite is bound to the particle surface of the one or more functional fillers, thereby reducing or avoiding the diffusion of unreacted polymer migrating from the composite in the event of unreacted polymer migrating from the composite.
9. The composite of any one of the preceding claims, wherein: the matrix comprises a silicone resin matrix; and the composite includes a sufficient amount of the silane coupling agent for improving dispersion during mixing of the one or more functional fillers within the silicone resin matrix, promoting adhesion between the silicone resin and the one or more functional fillers, and ensuring that unreacted polymer is bound to the particle surface of the one or more functional fillers, thereby avoiding easy diffusion of unreacted polymer out in the event of unreacted polymer, thereby reducing the exudation rate of silicone oil from the composite, making the composite substantially usable or fully usable without silicone oil migrating or being released beyond the confines of the composite.
10. The composite of any of the preceding claims, wherein, the composite includes a sufficient amount of the silane coupling agent such that the composite is configured to have a reduced silicone oil exudation rate from the composite over time of less than 2%, thereby making the composite substantially usable or fully usable without silicone oil migrating or being released beyond the confines of the composite.
11. The composite of any of the preceding claims, wherein, the composite includes a sufficient amount of the silane coupling agent such that the composite is configured to have a reduced silicone oil exudation rate over time of 1% or less.
12. The composite of any of the preceding claims, wherein, the composite includes a sufficient amount of the silane coupling agent such that the composite is configured to have a reduced silicone oil exudation rate over time of about 10% at day 12.
13. The composite of any of the preceding claims, wherein, the one or more functional fillers include one or more of: thermally conductive fillers; electrically conductive fillers; electromagnetic wave absorbing fillers; dielectric absorbing fillers; and fillers having two or more properties of thermally conductive, electrically conductive, dielectric absorbing, and electromagnetic wave absorbing.
14. The composite of any of the preceding claims, wherein: the one or more functional fillers include one or more alumina fillers within the matrix, such that the composite includes at least 90 weight percent of the one or more alumina fillers; and the composite has a thermal conductivity of at least 1 Watt per meter per Kelvin.
15. The complex of claim 14, wherein, the at least one or more alumina fillers within the matrix includes at least three different alumina fillers within the matrix.
16. The complex of claim 15, wherein, the at least three different alumina fillers include: a first alumina filler having a D50 average particle size of about 2 microns; a second alumina filler having a D50 average particle size of about 10 microns; and a third alumina filler having a D50 average particle size of about 70 microns.
17. The composite of claim 16, wherein: the first alumina filler includes alumina spherical particles having a D50 average particle size of about 2 microns; the second alumina filler includes alumina spherical particles having a D50 average particle size of about 10 microns; and the third alumina filler includes alumina spherical particles having a D50 average particle size of about 70 microns.
18. The complex of claim 16 or 17, wherein, the composite includes about 93.3 weight percent of the first, second, and third alumina fillers, based on the total weight of the composite.
19. The complex of claim 16, 17, or 18, wherein, the composite includes: about 23.30 weight percent of the first alumina filler; about 30 weight percent of the second alumina filler; and about 40 weight percent of the third alumina filler.
20. The complex of claim 16, 17, 18, or 19, wherein, the composite includes: about 16 volume percent to about 22 volume percent of the first alumina filler; about 20 volume percent to about 28 volume percent of the second alumina filler; and about 28 volume percent to about 36 volume percent of the third alumina filler.
21. The complex of claim 20, wherein, the composite includes: about 19 volume percent of the first alumina filler; about 24 volume percent of the second alumina filler; and about 32 volume percent of the third alumina filler.
22. The composite of any of the preceding claims, wherein, the composite is configured to have a greater than 30 percent recovery rate for a 2.5 millimeter thickness, a peak force of less than 100 PSI for 50 percent compression, and a residual force of less than 20 PSI for 50 percent compression.
23. The composite of any of the preceding claims, wherein, the composite has a thermal conductivity of at least 2 Watts per meter per Kelvin.
24. The composite of any of the preceding claims, wherein, the composite is configured to have: a reduced silicone oil exudation rate over time of less than 2 percent; a deflection rate of greater than 50 percent at 30 pounds per square inch (PSI) for a 2 millimeter thickness; a thermal resistance of less than 0.45 at 10 PSI for a 1 millimeter thickness; a hardness of less than 45 Shore 00; and a greater than 30 percent recovery rate for a 2.5 millimeter thickness, a peak force of less than 100 PSI for 50 percent compression, and a residual force of less than 20 PSI for 50 percent compression.
25. The complex according to any one of the preceding claims, wherein, the composite is configured to have: a thermal conductivity of at least 3.4 Watts per meter per Kelvin; a reduced silicone oil exudation rate over time of 1 percent or less and / or about 10 percent at day 12; a deflection rate of at least 61 percent at 30 PSI for a 2mm thickness; a thermal resistance of 0.318 or less at 10 PSI for a 1 millimeter thickness; 31 a hardness of 0 Shore 00 or less; and a recovery of at least 46% for a 2.5 millimeter thickness, a peak force of 25 PSI or less for a 50% compression, and a force at 50% compression of 5.6 PSI or less.
26. The complex according to any one of the preceding claims, wherein, The composite includes a crosslinked thermally conductive gap pad having a thermal conductivity of at least 3.4 Watts per meter and an oil bleed of about 10% at 12 days.
27. The complex according to any one of the preceding claims, wherein, The composite includes a thermally conductive gap pad.
28. A method of reducing hardness and / or reducing diffusion of material migrating from a composite for managing heat and / or electromagnetic interference (EMI), the method comprising adding a silane coupling agent to the composite such that the composite includes at least about 0.5 weight percent of the silane coupling agent based on a total weight of the composite.
29. The method of claim 28, wherein, The method includes adding the silane coupling agent to the composite such that the composite includes at least about 0.5 weight percent but no more than about 1 weight percent of the silane coupling agent.
30. The method of claim 28 or 29, wherein, The method includes adding the silane coupling agent to the composite such that the composite includes at least about 0.1 volume percent of the silane coupling agent.
31. The method of any one of claims 28-30, wherein, The method includes adding the silane coupling agent to the composite such that the composite includes at least about 0.1 volume percent but no more than about 0.6 volume percent of the silane coupling agent.
32. The method of any one of claims 28-31, wherein, The method includes adding the silane coupling agent to the composite such that the composite includes about 0.93 weight percent and about 0.3 volume weight percent of the silane coupling agent.
33. The method of any one of claims 28-32, wherein, The silane coupling agent includes hexadecyltrimethoxysilane.
34. The method of any one of claims 28-33, wherein, The method includes adding a sufficient amount of the silane coupling agent to reduce hardness of the composite such that the composite is configured to have a high recovery and a low compression force.
35. The method of any one of claims 28-34, wherein, The method includes adding a sufficient amount of the silane coupling agent to ensure that unreacted polymer of the composite is bound to particle surfaces of one or more functional filler particles of the composite, thereby reducing or avoiding diffusion of unreacted polymer migrating from the composite with unreacted polymer migrating from the composite.
36. The method of any one of claims 28 to 35, wherein: The composite includes a silicone resin matrix and one or more functional filler particles within the silicone resin matrix; and The method includes adding a sufficient amount of silane coupling agent for improving dispersion during mixing of the one or more functional filler particles within the silicone resin matrix, promoting adhesion between the silicone resin and the one or more functional fillers, and ensuring that unreacted polymer is bound to particle surfaces of the one or more functional fillers, thereby avoiding unreacted polymer from readily diffusing out, thereby reducing an oil bleed of silicone oil exuding from the composite, making the composite substantially usable or fully usable without silicone oil migrating or being released beyond the composite.