Thermally conductive EMI absorber

Abstract

A thermally conductive EMI absorber. Exemplary embodiments of thermally conductive EMI absorbers are disclosed. In an exemplary embodiment, the thermally conductive EMI absorber may have a thermal conductivity of at least 6 watts per meter per Kelvin (W / mK) and an attenuation of greater than 15 decibels per centimeter (dB / cm) at frequencies of 10 gigahertz (GHz) or greater.

Description

[0001] This application is a divisional application of the original invention patent application with application number 202111108695.1 (application date: September 22, 2021, invention name: Thermally Conductive EMI Absorber). Technical Field

[0002] The present disclosure relates to thermally conductive EMI absorbers. Background Art

[0003] This section provides background information related to the present disclosure which is not necessarily prior art.

[0004] Electrical components such as semiconductors, integrated circuit packages, transistors, etc. typically have pre-designed temperatures at which the electrical components operate optimally. Ideally, the pre-designed temperature is close to the temperature of the surrounding air. However, the operation of the electrical components generates heat. If the heat is not removed, the electrical components may operate at a temperature significantly higher than their normal or desirable operating temperature. Such excessively high temperatures may adversely affect the operating characteristics of the electrical components and the operation of the associated devices.

[0005] In order to avoid or at least reduce the adverse operating characteristics from heat generation, heat should be removed, for example, by conducting the heat from the operating electrical components to the 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 by direct surface contact between the electrical components and the heat sink and / or by 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 heat transfer efficiency compared to filling the gaps with air (a relatively poor thermal conductor).

[0006] In addition, a common problem in the operation of electronic devices is the generation of electromagnetic radiation within the electronic circuits of the device. This radiation can cause electromagnetic interference (EMI) or radio frequency interference (RFI), which 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.

[0007] A common solution to mitigate the effects of EMI / RFI is through the use of shields that can absorb and / or reflect and / or redirect EMI energy. These shields are typically employed to keep the EMI / RFI within its source and isolate other devices adjacent to the EMI / RFI source.

[0008] As used herein, the term "EMI" should be considered to include and refer generally to EMI emissions and RFI emissions, and the term "electromagnetic" should be considered to include and refer generally to electromagnetic frequencies and radio frequencies from external and internal sources. 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 EMI and / or RFI no longer interferes, for example, with government compliance and / or internal functions of electronic component systems. Summary of the invention

[0009] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0010] Exemplary embodiments disclose thermally conductive electromagnetic interference (EMI) absorbers. In exemplary embodiments, the thermally conductive EMI absorbers may have a thermal conductivity of at least 6 watts per meter per Kelvin (W / mK) and an attenuation greater than 15 decibels per centimeter (dB / cm) at frequencies of 10 gigahertz (GHz) or higher.

[0011] In an exemplary embodiment, the thermally conductive EMI absorber has a thermal conductivity of at least 11 W / mK.

[0012] In an exemplary embodiment, the thermally conductive EMI absorber has a thermal conductivity of at least 11.5 W / mK.

[0013] In an exemplary embodiment, the thermally conductive EMI absorber has a thermal conductivity of at least 12 W / mK.

[0014] In an exemplary embodiment, the thermally conductive EMI absorber has:

[0015] Attenuation greater than 34 dB / cm at frequencies of 20 GHz or higher;

[0016] Attenuation greater than 66 dB / cm at frequencies of 40 GHz or higher; and

[0017] Greater than 90dB / cm attenuation at frequencies of 60GHz or higher.

[0018] In an exemplary embodiment, the thermally conductive EMI absorber has:

[0019] Attenuation of at least 22dB / cm at a frequency of 10GHz;

[0020] Attenuation of at least 39dB / cm at a frequency of 20GHz;

[0021] At least 53dB / cm attenuation at 28GHz;

[0022] Attenuation of at least 76 dB / cm at 39 GHz; and

[0023] At least 135dB / cm attenuation at 77GHz.

[0024] In an exemplary embodiment, the thermally conductive EMI absorber has a thermal conductivity of at least 11.5 W / mK.

[0025] In an exemplary embodiment:

[0026] The thermally conductive EMI absorber has a hardness of about 58 Shore 00 or less at three seconds and about 37 Shore 00 or less at thirty seconds;

[0027] The thermally conductive EMI absorber has a UL flammability rating of UL V-0;

[0028] The thermally conductive EMI absorber is dielectric rather than conductive; and

[0029] The thermally conductive EMI absorber does not include silicone, is substantially completely free of silicone, and / or is capable of being used without silicone migration.

[0030] In an exemplary embodiment:

[0031] The thermally conductive EMI absorber comprises at least 90% by weight of the at least one functional filler; and the thermally conductive EMI absorber comprises less than 10% by weight of the matrix; and / or

[0032] The thermally conductive EMI absorber includes at least 80% by volume of the at least one functional filler, and the thermally conductive EMI absorber includes less than 20% by volume of the matrix.

[0033] In an exemplary embodiment:

[0034] The matrix comprises a thermoreversible oleogel; and / or

[0035] The matrix comprises a block copolymer and a process oil,

[0036] The matrix comprises a diblock copolymer and / or a triblock copolymer.

[0037] In an exemplary embodiment, the matrix includes a process oil and a block copolymer without chemical cross-linking such that the thermally conductive EMI absorber is a thermally reversible thermoplastic material.

[0038] In an exemplary embodiment, the at least one functional filler includes one or more of zinc oxide, silicon carbide, carbonyl iron, aluminum oxide, aluminum nitride, aluminum, boron nitride, silicon nitride, iron, graphite, ferrite, aluminum hydroxide, and / or silica.

[0039] In an exemplary embodiment:

[0040] The at least one functional filler consists essentially of carbonyl iron, silicon carbide, zinc oxide, aluminum nitride and aluminum oxide; or

[0041] The at least one functional filler consists essentially of zinc oxide, silicon carbide and aluminum nitride; or

[0042] The at least one functional filler consists essentially of silicon carbide and aluminum oxide.

[0043] In an exemplary embodiment, the matrix includes a process oil, a diblock polymer, a coupling agent, and silica.

[0044] In an exemplary embodiment, the matrix includes a paraffin process oil, a styrene-ethylene-propylene (SEP) linear polymer having a diblock structure, and a coupling agent.

[0045] In an exemplary embodiment, the matrix includes a non-silicone polymer matrix.

[0046] In an exemplary embodiment, the non-silicone polymer matrix comprises a non-silicone oil gel resin, and / or wherein the non-silicone polymer matrix comprises:

[0047] Styrene and ethylene / butylene copolymers; and / or

[0048] Styrene and ethylene / propylene copolymers.

[0049] In an exemplary embodiment:

[0050] The matrix includes a process oil, a diblock polymer, and a coupling agent; and

[0051] The at least one functional filler includes silicon carbide.

[0052] In an exemplary embodiment:

[0053] The at least one functional filler further comprises aluminum oxide; or

[0054] The at least one functional filler further comprises zinc oxide, carbonyl iron, aluminum nitride and aluminum oxide; or

[0055] The at least one functional filler further comprises zinc oxide and aluminum nitride.

[0056] In an exemplary embodiment:

[0057] The thermally conductive EMI absorber has a UL flammability rating of UL V-0;

[0058] The thermally conductive EMI absorber is dielectric rather than conductive; and

[0059] The thermally conductive EMI absorber does not include silicone, is substantially completely free of silicone, and / or is capable of being used without silicone migration.

[0060] In an exemplary embodiment:

[0061] The at least one functional filler comprises zinc oxide, silicon carbide and aluminum nitride;

[0062] The matrix includes paraffin process oil, styrene-ethylene-propylene (SEP) linear polymer with a diblock structure, and a coupling agent;

[0063] The thermally conductive EMI absorber comprises at least 93% by weight of the at least one functional filler and no more than 7% by weight of the matrix; and

[0064] The thermally conductive EMI absorber includes at least 81% by volume of the at least one functional filler and no more than 19% by volume of the matrix.

[0065] In an exemplary embodiment, the thermally conductive EMI absorber includes about 1.5% to about 2% by weight zinc oxide, about 16% to about 19% by weight aluminum nitride, about 70% to about 80% by weight silicon carbide, about 4% to about 6% by weight paraffin process oil, about 0.4% to about 0.8% by weight styrene-ethylene-propylene (SEP) linear polymer having a diblock structure, and about 0.5% to about 1% by weight coupling agent.

[0066] In an exemplary embodiment:

[0067] The at least one functional filler comprises carbonyl iron, silicon carbide, zinc oxide, aluminum nitride and aluminum oxide;

[0068] The matrix includes paraffin process oil, styrene-ethylene-propylene (SEP) linear polymer with a diblock structure, and a coupling agent;

[0069] The thermally conductive EMI absorber comprises at least 95% by weight of the at least one functional filler and no more than 10% by weight of the matrix; and

[0070] The thermally conductive EMI absorber includes at least 83% by volume of the at least one functional filler and no more than 17% by volume of the matrix.

[0071] In an exemplary embodiment, the thermally conductive EMI absorber includes about 23% to about 29% by weight carbonyl iron, about 0.8% to about 1.2% by weight zinc oxide, about 5% to about 5.7% by weight aluminum nitride, about 58% to about 67% by weight silicon carbide, about 16% to about 21% by weight alumina, about 3% to about 5% by weight paraffin process oil, about 0.3% to about 0.7% by weight styrene-ethylene-propylene (SEP) linear polymer having a diblock structure, and about 0.4% to about 0.6% by weight coupling agent.

[0072] In an exemplary embodiment:

[0073] The at least one functional filler comprises zinc oxide, silicon carbide and aluminum nitride;

[0074] The matrix includes paraffin process oil, styrene-ethylene-butylene-styrene SEBS linear polymer with a triblock structure, styrene-ethylene-propylene SEP linear polymer with a diblock structure and a coupling agent;

[0075] The thermally conductive EMI absorber comprises at least 93% by weight of the at least one functional filler and no more than 7% by weight of the matrix; and

[0076] The thermally conductive EMI absorber includes at least 81% by volume of the at least one functional filler and no more than 19% by volume of the matrix.

[0077] In an exemplary embodiment, the thermally conductive EMI absorber includes about 1.5% to about 2% by weight zinc oxide, about 16% to about 19% by weight aluminum nitride, about 70% to about 80% by weight silicon carbide, about 4% to about 6% by weight paraffin process oil, about 0.2% to 0.4% by weight styrene-ethylene-butylene-styrene SEBS linear polymer having a triblock structure, about 0.2% to about 0.4% by weight styrene-ethylene-propylene SEP linear polymer having a diblock structure, and about 0.5% to about 1% by weight coupling agent.

[0078] In an exemplary embodiment:

[0079] The at least one functional filler comprises carbonyl iron, silicon carbide, zinc oxide, aluminum nitride and aluminum oxide;

[0080] The matrix includes paraffin process oil, styrene-ethylene-butylene-styrene SEBS linear polymer with a triblock structure, styrene-ethylene-propylene SEP linear polymer with a diblock structure and a coupling agent;

[0081] The thermally conductive EMI absorber comprises at least 95% by weight of the at least one functional filler and no more than 5% by weight of the matrix; and

[0082] The thermally conductive EMI absorber includes at least 83% by volume of the at least one functional filler and no more than 17% by volume of the matrix.

[0083] In an exemplary embodiment, the thermally conductive EMI absorber includes about 23% to about 29% by weight carbonyl iron, about 0.8% to about 1.2% by weight zinc oxide, about 5% to about 5.7% by weight aluminum nitride, about 58% to about 67% by weight silicon carbide, about 16% to about 21% by weight aluminum oxide, about 3% to about 5% by weight paraffin process oil, about 0.2% to about 0.4% by weight styrene-ethylene-butylene-styrene SEBS linear polymer having a triblock structure, about 0.1% to about 0.3% by weight styrene-ethylene-propylene SEP linear polymer having a diblock structure, and about 0.4% to about 0.6% by weight coupling agent.

[0084] In an exemplary embodiment:

[0085] The at least one functional filler comprises silicon carbide and aluminum oxide;

[0086] The matrix includes a process oil, a diblock polymer, a coupling agent, an antioxidant and silica;

[0087] The thermally conductive EMI absorber comprises at least 94.5% by weight of the at least one functional filler and no more than 5.5% by weight of the matrix; and

[0088] The thermally conductive EMI absorber includes at least 80% by volume of the at least one functional filler and no more than 20% by volume of the matrix.

[0089] In an exemplary embodiment, the thermally conductive EMI absorber includes about 69% to about 74% by weight silicon carbide, about 20% to about 25% by weight alumina, about 2.5% to about 5% by weight process oil, about 0.3% to about 0.7% by weight diblock polymer, about 0.2% to about 0.6% by weight coupling agent, about 0.5% to about 0.9% by weight silica, and less than about 0.1% by weight antioxidant.

[0090] Further areas of applicability will become apparent from the description provided herein.The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0091] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0092] Figure 1An exemplary embodiment of a thermally conductive EMI absorber positioned between a plate shield and an integrated circuit or chip is shown. Figure 1 Also shown is a conventional thermal pad located between the heat sink and the plate shield.

[0093] Figure 2 is a graph of attenuation (decibels per centimeter (dB / cm)) versus frequency (gigahertz (GHz)) for a thermally conductive EMI absorber according to an exemplary embodiment.

[0094] Figure 3 is a graph of percent deflection (%) versus pressure (kilopascals (kPa)) for a thermally conductive EMI absorber having a starting thickness of 1 millimeter (mm) according to an exemplary embodiment.

[0095] Figure 4 is the thermal resistance (in degrees Celsius per square cm / watt (C*cm) of the thermally conductive EMI absorber according to an exemplary embodiment. 2 / W)) versus Pressure (kPa), where the thermally conductive EMI absorber has a starting thickness of 1 mm.

[0096] Figure 5 is a plot of attenuation (decibels (dB / cm)) versus frequency (GHz) for an exemplary embodiment of a thermally conductive EMI absorber.

[0097] Figure 6 is the thermal resistance (C*cm) of an exemplary embodiment of a thermally conductive EMI absorber at 50°C according to ASTM D5470 2 / W) versus pressure in pounds per square inch (psi).

[0098] Figure 7 is a line graph of percent deflection (%) versus pressure (psi) for a thermally conductive EMI absorber according to an exemplary embodiment. DETAILED DESCRIPTION

[0099] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0100] As recognized herein, there is a need for materials that are both highly thermally conductive and efficient microwave absorbers, so that a single material can be used in applications where both thermal radiation and stray radiation are issues, rather than two separate materials. For example, it is not uncommon to use two different interface materials for different functions within an application, such as one material optimized for thermal conductivity properties and another optimized for absorption properties. It is also recognized herein that higher thermal conductivities (e.g., greater than 6 W / mK, etc.) are needed to meet the ever-increasing heat dissipation needs without sacrificing absorption properties.

[0101] Thus, disclosed herein are exemplary embodiments of thermally conductive electromagnetic interference (EMI) absorbers having a thermal conductivity greater than 6 W / mK (e.g., at least about 11 W / mK, at least about 11.5 W / mK, at least about 12 W / mK, etc.) and attenuation greater than 15 decibels per centimeter (dB / cm) at frequencies of 10 gigahertz (GHz) or higher, etc. Thus, disclosed herein are exemplary embodiments of thermally conductive EMI absorbers that can be used as a single interface material having both high thermal conductivity and effective absorption. The thermally conductive EMI absorber is configured to have the combined properties of a thermal interface material and an EMI absorber.

[0102] Therefore, the thermally conductive EMI absorber disclosed in this article can be used to establish a thermally conductive heat path with high thermal conductivity (e.g., at least about 11 W / mK, etc.) between a heat source (e.g., an integrated circuit, etc.) and a heat dissipation / heat removal structure (e.g., a plate shield, a heat sink, etc.), while also suppressing, for example, radiated electromagnetic field coupling between the integrated circuit and the heat sink.

[0103] For example, Figure 1 An exemplary embodiment of a thermally conductive EMI absorber 100 is shown positioned between a plate shield 104 and an integrated circuit or chip 108 . Figure 1 Also shown is a conventional thermal interface material 112 located between the heat sink 116 and the plate shield 104. Figure 1 In the illustrated embodiment, the thermally conductive EMI absorber 100 may operate as a thermal interface material for establishing a thermally conductive heat path from the integrated circuit 108 to the plate shield 104. The thermally conductive EMI absorber 100 may also operate as an EMI absorber for suppressing radiated electromagnetic field coupling between the integrated circuit 108 and the heat sink 116. Thus, the thermally conductive EMI absorber 100 may provide the combined performance of a thermal interface material and an EMI absorber in a dual-purpose, single product solution that saves space.

[0104] In an exemplary embodiment, the thermally conductive EMI absorber has a thermal conductivity of at least 6 W / mK (e.g., at least about 11 W / mK, at least about 11.5 W / mK, at least about 12 W / mK, etc.), an attenuation of greater than 15 dB / cm at frequencies of 10 GHz or higher, an attenuation of greater than 34 dB / cm at frequencies of 20 GHz or higher, an attenuation of greater than 66 dB / cm at frequencies of 40 GHz or higher, and an attenuation of greater than 90 dB / cm at frequencies of 60 GHz or higher. Continuing with this example, the thermally conductive EMI absorber may include a silicone-free gap filling pad that is initially provided in sheet form (e.g., 18 inch by 18 inch sheets, etc.) with a sheet thickness ranging from 0.5 mm to 5 mm. The thermally conductive EMI absorber may be disposed between the isolation liners as a sheet or die cut portion. Alternatively, the thermally conductive EMI absorber may be configured differently (e.g., with a different matrix system, etc.) such that the thermally conductive EMI absorber includes a phase change, grease, putty, or other non-pad form. The thermally conductive EMI absorber may have one or more properties shown in Table 1 and / or Table 2 below.

[0105] In an exemplary embodiment, the thermally conductive EMI absorber includes a matrix and at least one functional filler in the matrix. The thermally conductive EMI absorber has a thermal conductivity greater than 6 W / mK and an attenuation greater than 15 decibels per centimeter (dB / cm) at frequencies of 10 gigahertz (GHz) or higher.

[0106] In some exemplary embodiments, the thermally conductive EMI absorber has a thermal conductivity of at least 11 W / mK (e.g., 11 W / mK, 11.5 W / mK, 12 W / mK, greater than 12 W / mK, etc.) Additionally, the thermally conductive EMI absorber has an attenuation greater than 15 dB / cm at frequencies of 10 GHz or higher, greater than 34 dB / cm at frequencies of 20 GHz or higher, greater than 66 dB / cm at frequencies of 40 GHz or higher, and / or greater than 90 dB / cm at frequencies of 60 GHz or higher.

[0107] In some exemplary embodiments, the matrix includes a thermoreversible oil gel, which includes a process oil (e.g., paraffin oil, etc.) and a block copolymer. The block copolymer may include a diblock copolymer (e.g., a diblock styrene copolymer, etc.) and / or a triblock copolymer (e.g., a triblock styrene copolymer, etc.).

[0108] In some exemplary embodiments, the process oil and the block copolymer are not chemically cross-linked, such that the thermally conductive EMI absorber is a thermally reversible thermoplastic material. For example, the matrix may include a thermoplastic silicone-free polymer oil gel resin.

[0109] In some exemplary embodiments, the matrix includes a non-silicone polymer matrix such as a non-silicone oil gel resin. The non-silicone polymer matrix may include styrene and ethylene / butylene copolymers and / or styrene and ethylene / propylene copolymers. The thermally conductive EMI absorber may be configured to include a non-silicone gap filler pad, putty, grease, or phase change material that does not contain silicone. In alternative embodiments, the thermally conductive EMI absorber may include a silicone-based matrix system.

[0110] In some exemplary embodiments, the matrix includes a paraffin process oil, a styrene-ethylene-propylene (SEP) linear polymer having a diblock structure, and a coupling agent. In alternative exemplary embodiments, in addition to or as an alternative to the styrene-ethylene-propylene (SEP) linear polymer having a diblock structure, the matrix may include a styrene-ethylene-butylene-styrene (SEBS) linear polymer having a triblock structure.

[0111] In some exemplary embodiments, at least one functional filler within the matrix includes one or more of zinc oxide, silicon carbide, carbonyl iron, aluminum oxide, aluminum nitride, aluminum, boron nitride, silicon nitride, iron, graphite, ferrite, aluminum hydroxide, and / or silica. The thermally conductive EMI absorber may include at least 90% by weight of the at least one functional filler and no more than 10% by weight of the matrix. The thermally conductive EMI absorber may include at least 80% by volume of the at least one functional filler and no more than 20% by volume of the matrix. The at least one functional filler may include different grades (e.g., different sizes, different purities, different shapes, etc.) of the same (or different) functional filler. For example, the thermally conductive EMI absorber may include two or more (e.g., four, five, etc.) different grades (e.g., sizes, etc.) of silicon carbide. Other suitable fillers and / or additives may also be added to the thermally conductive EMI absorber, such as pigments, plasticizers, processing aids, flame retardants, extenders, adhesion promoters, antioxidants, ultraviolet (UV) stabilizers, etc.

[0112] In some exemplary embodiments, at least one functional filler includes carbonyl iron, silicon carbide, zinc oxide, aluminum nitride, and aluminum oxide (e.g., consisting only of them, etc.). And, the matrix includes paraffin process oil, a styrene-ethylene-propylene (SEP) linear polymer having a diblock structure, and a coupling agent (e.g., consisting only of them, etc.). The matrix may also include or alternatively include a styrene-ethylene-butylene-styrene (SEBS) linear polymer having a triblock structure. In these exemplary embodiments, the thermally conductive EMI absorber includes at least 90% by weight of at least one functional filler (carbonyl iron, silicon carbide, zinc oxide, aluminum nitride, and aluminum oxide) and no more than 10% by weight of the matrix. The thermally conductive EMI absorber includes at least 80% by volume of at least one functional filler (carbonyl iron, silicon carbide, zinc oxide, aluminum nitride, and aluminum oxide) and no more than 20% by volume of the matrix.

[0113] In other exemplary embodiments, at least one functional filler includes zinc oxide, silicon carbide, and aluminum nitride (e.g., consisting only of them, etc.). And, the matrix includes paraffin process oil, a styrene-ethylene-propylene (SEP) linear polymer having a diblock structure, and a coupling agent (e.g., consisting only of them, etc.). The matrix may also or alternatively include a styrene-ethylene-butylene-styrene (SEBS) linear polymer having a triblock structure. In these other exemplary embodiments, the thermally conductive EMI absorber includes at least 90% by weight of at least one functional filler (zinc oxide, silicon carbide, and aluminum nitride) and no more than 10% by weight of the matrix. The thermally conductive EMI absorber includes at least 80% by volume of at least one functional filler (zinc oxide, silicon carbide, and aluminum nitride) and no more than 20% by volume of the matrix.

[0114] In additional exemplary embodiments, at least one functional filler includes (e.g., consists only of) alumina and silicon carbide. And, the matrix includes (e.g., consists only of) a process oil, a diblock polymer, a coupling agent, an antioxidant, and silica (e.g., consists only of, etc.). The matrix may also or alternatively include a triblock polymer. In these additional exemplary embodiments, the thermally conductive EMI absorber includes at least 90% by weight of at least one functional filler (alumina and silicon carbide) and no more than 10% by weight of the matrix. The thermally conductive EMI absorber includes at least 80% by volume of at least one functional filler (alumina and silicon carbide) and no more than 20% by volume of the matrix.

[0115] In some exemplary embodiments, the thermally conductive EMI absorber may have a hardness of about 68 Shore 00 or less at three seconds and a hardness of about 55 Shore 00 or less at thirty seconds. As an example, the thermally conductive EMI absorber may have a hardness of about 58 Shore 00 at three seconds and a hardness of about 37 Shore 00 or less at thirty seconds. Or for example, the thermally conductive EMI absorber may have a hardness of about 58 Shore 00 at three seconds and a hardness of about 31 Shore 00 or less at thirty seconds. The thermally conductive EMI absorber is dielectric rather than conductive. The thermally conductive EMI absorber does not contain silicone, is free of silicone (e.g., completely free of silicone, substantially free of silicone, contains no detectable silicone, etc.), and / or can be used without silicone migration, whereby the thermally conductive EMI absorber is suitable for silicone sensitive applications. In an alternative embodiment, the thermally conductive EMI absorber includes a silicone-based matrix system.

[0116] The thermally conductive EMI absorber may be configured as a gap filling pad, phase change material, putty, grease, or sheet. For example, the thermally conductive EMI absorber may include a thermoplastic pad configured to undergo physical crosslinking (not chemical crosslinking) as the temperature decreases from an elevated temperature to room temperature (e.g., about 20 degrees Celsius (° C.), etc.).

[0117] In another exemplary embodiment, a thermally conductive EMI absorber includes a matrix and at least one functional filler in the matrix. In this example, the at least one functional filler includes or consists essentially of zinc oxide, silicon carbide, and aluminum nitride. And, the matrix includes or consists essentially of a paraffin process oil, a styrene-ethylene-propylene (SEP) linear polymer having a diblock structure, and a coupling agent. Continuing with this example, the thermally conductive EMI absorber includes at least 90% by weight (e.g., at least 93% by weight, etc.) of at least one functional filler (zinc oxide, silicon carbide, aluminum nitride) and no more than 10% by weight (e.g., no more than 7% by weight, etc.) of the matrix. In addition, the thermally conductive EMI absorber includes at least 80% by volume (e.g., at least 81% by volume, etc.) of at least one functional filler (zinc oxide, silicon carbide, aluminum nitride) and no more than 20% by volume (e.g., no more than 19% by volume, etc.) of the matrix. For example, the thermally conductive EMI absorber may include about 1.5% to about 2% by weight zinc oxide, about 16% to about 19% by weight aluminum nitride, about 70% to about 80% by weight silicon carbide, about 4% to about 6% by weight paraffin process oil, about 0.4% to about 0.8% by weight styrene-ethylene-propylene (SEP) linear polymer having a diblock structure, and about 0.5% to about 1% by weight coupling agent. The thermally conductive EMI absorber has a thermal conductivity of at least 11 W / mK (e.g., 11 W / mK, 12 W / mK, greater than 12 W / mK, etc.). The thermally conductive EMI absorber has an attenuation of greater than 15 decibels per centimeter (dB / cm) at a frequency of 10 gigahertz (GHz) or higher, an attenuation of greater than 34 dB / cm at a frequency of 20 GHz or higher, an attenuation of greater than 66 dB / cm at a frequency of 40 GHz or higher, and an attenuation of greater than 90 dB / cm at a frequency of 60 GHz or higher. The thermally conductive EMI absorber has a hardness of about 68 Shore 00 or less at three seconds and a hardness of about 55 Shore 00 or less at thirty seconds. The thermally conductive EMI absorber is dielectric and not conductive. The thermally conductive EMI absorber does not include silicone and is silicone-free, so that the thermally conductive EMI absorber can be used without silicone migration. The thermally conductive EMI absorber is configured as a gap filling pad, a phase change material, a putty, a grease, or a sheet.

[0118] In another exemplary embodiment, a thermally conductive EMI absorber includes a matrix and at least one functional filler in the matrix. In this example, the at least one functional filler includes or consists essentially of carbonyl iron, silicon carbide, zinc oxide, aluminum nitride, and aluminum oxide. And, the matrix includes or consists essentially of paraffin process oil, a styrene-ethylene-propylene (SEP) linear polymer having a diblock structure, and a coupling agent. Continuing with this example, the thermally conductive EMI absorber includes at least 90% by weight (e.g., at least 95% by weight, etc.) of at least one functional filler (carbonyl iron, silicon carbide, zinc oxide, aluminum nitride, and aluminum oxide) and no more than 10% by weight (e.g., no more than 5% by weight, etc.) of the matrix. In addition, the thermally conductive EMI absorber includes at least 80% by volume (e.g., at least 83% by volume, etc.) of at least one functional filler (carbonyl iron, silicon carbide, zinc oxide, aluminum nitride, and aluminum oxide) and no more than 20% by volume (e.g., no more than 17% by volume, etc.) of the matrix. For example, the thermally conductive EMI absorber may include carbonyl iron of about 23% to about 29% by weight, zinc oxide of about 0.8% to about 1.2% by weight, aluminum nitride of about 5% to about 5.7% by weight, silicon carbide of about 58% to about 67% by weight, aluminum oxide of about 16% to about 21% by weight, paraffin process oil of about 3% to about 5% by weight, styrene-ethylene-propylene (SEP) linear polymer having a diblock structure of about 0.3% to about 0.7% by weight, and coupling agent of about 0.4% to about 0.6% by weight. The thermally conductive EMI absorber has a thermal conductivity of at least 11 W / mK (e.g., 11 W / mK, 12 W / mK, higher than 12 W / mK, etc.). The thermally conductive EMI absorber has an attenuation of greater than 15 decibels per centimeter (dB / cm) at a frequency of 10 gigahertz (GHz) or higher, an attenuation of greater than 34 dB / cm at a frequency of 20 GHz or higher, an attenuation of greater than 66 dB / cm at a frequency of 40 GHz or higher, and an attenuation of greater than 90 dB / cm at a frequency of 60 GHz or higher. The thermally conductive EMI absorber has a hardness of about 68 Shore 00 or less at three seconds and a hardness of about 55 Shore 00 or less at thirty seconds. The thermally conductive EMI absorber is dielectric rather than conductive. The thermally conductive EMI absorber does not include silicone and is silicone-free, so that the thermally conductive EMI absorber can be used without silicone migration. The thermally conductive EMI absorber is configured as a gap filling pad, a phase change material, a putty, a grease, or a sheet.

[0119] In another exemplary embodiment, a thermally conductive EMI absorber includes a matrix and at least one functional filler in the matrix. In this example, the at least one functional filler includes or consists essentially of zinc oxide, silicon carbide, and aluminum nitride. And, the matrix includes or consists essentially of paraffin process oil, a styrene-ethylene-butylene-styrene (SEBS) linear polymer having a triblock structure, a styrene-ethylene-propylene (SEP) linear polymer having a diblock structure, and a coupling agent. Continuing with this example, the thermally conductive EMI absorber includes at least 90% by weight (e.g., at least 93% by weight, etc.) of at least one functional filler (zinc oxide, silicon carbide, aluminum nitride) and no more than 10% by weight (e.g., no more than 7% by weight, etc.) of the matrix. In addition, the thermally conductive EMI absorber includes at least 80% by volume (e.g., at least 81% by volume, etc.) of at least one functional filler (zinc oxide, silicon carbide, aluminum nitride) and no more than 20% by volume (e.g., no more than 19% by volume, etc.) of the matrix. For example, the thermally conductive EMI absorber may include about 1.5% to about 2% by weight zinc oxide, about 16% to about 19% by weight aluminum nitride, about 70% to about 80% by weight silicon carbide, about 4% to about 6% by weight paraffin process oil, about 0.2% to 0.4% by weight styrene-ethylene-butylene-styrene (SEBS) linear polymer having a triblock structure, about 0.2% to about 0.4% by weight styrene-ethylene-propylene (SEP) linear polymer having a diblock structure, and about 0.5% to about 1% by weight coupling agent. The thermally conductive EMI absorber has a thermal conductivity of at least 11 W / mK (e.g., 11 W / mK, 12 W / mK, higher than 12 W / mK, etc.). The thermally conductive EMI absorber has an attenuation of greater than 15 decibels per centimeter (dB / cm) at a frequency of 10 gigahertz (GHz) or higher, an attenuation of greater than 34 dB / cm at a frequency of 20 GHz or higher, an attenuation of greater than 66 dB / cm at a frequency of 40 GHz or higher, and an attenuation of greater than 90 dB / cm at a frequency of 60 GHz or higher. The thermally conductive EMI absorber has a hardness of about 68 Shore 00 or less at three seconds and a hardness of about 55 Shore 00 or less at thirty seconds. The thermally conductive EMI absorber is dielectric and not conductive. The thermally conductive EMI absorber does not include silicone and is silicone-free, so that the thermally conductive EMI absorber can be used without silicone migration. The thermally conductive EMI absorber is configured as a gap filling pad, a phase change material, a putty, a grease, or a sheet.

[0120] In another exemplary embodiment, a thermally conductive EMI absorber includes a matrix and at least one functional filler in the matrix. In this example, the at least one functional filler includes or consists essentially of carbonyl iron, silicon carbide, zinc oxide, aluminum nitride, and aluminum oxide. And, the matrix includes or consists essentially of paraffin process oil, styrene-ethylene-butylene-styrene (SEBS) linear polymer having a triblock structure, styrene-ethylene-propylene (SEP) linear polymer having a diblock structure, and a coupling agent. Continuing with this example, the thermally conductive EMI absorber includes at least 90% by weight (e.g., at least 95% by weight, etc.) of at least one functional filler (carbonyl iron, silicon carbide, zinc oxide, aluminum nitride, and aluminum oxide) and no more than 10% by weight (e.g., no more than 5% by weight, etc.) of the matrix. In addition, the thermally conductive EMI absorber includes at least 80% by volume (e.g., at least 83% by volume, etc.) of at least one functional filler (carbonyl iron, silicon carbide, zinc oxide, aluminum nitride, and aluminum oxide) and no more than 20% by volume (e.g., no more than 17% by volume, etc.) of the matrix. For example, the thermally conductive EMI absorber may include carbonyl iron of about 23% to about 29% by weight, zinc oxide of about 0.8% to about 1.2% by weight, aluminum nitride of about 5% to about 5.7% by weight, silicon carbide of about 58% to about 67% by weight, aluminum oxide of about 16% to about 21% by weight, paraffin process oil of about 3% to about 5% by weight, styrene-ethylene-butylene-styrene (SEBS) linear polymer having a triblock structure of about 0.2% to about 0.4% by weight, styrene-ethylene-propylene (SEP) linear polymer having a diblock structure of about 0.1% to about 0.3% by weight, and coupling agent of about 0.4% to about 0.6% by weight. The thermally conductive EMI absorber has a thermal conductivity of at least 11 W / mK (e.g., 11 W / mK, 12 W / mK, higher than 12 W / mK, etc.). The thermally conductive EMI absorber has an attenuation of greater than 15 decibels per centimeter (dB / cm) at a frequency of 10 gigahertz (GHz) or higher, an attenuation of greater than 34 dB / cm at a frequency of 20 GHz or higher, an attenuation of greater than 66 dB / cm at a frequency of 40 GHz or higher, and an attenuation of greater than 90 dB / cm at a frequency of 60 GHz or higher. The thermally conductive EMI absorber has a hardness of about 68 Shore 00 or less at three seconds and a hardness of about 55 Shore 00 or less at thirty seconds. The thermally conductive EMI absorber is dielectric and not conductive. The thermally conductive EMI absorber does not include silicone and is silicone-free, so that the thermally conductive EMI absorber can be used without silicone migration. The thermally conductive EMI absorber is configured as a gap filling pad, a phase change material, a putty, a grease, or a sheet.

[0121] In another exemplary embodiment, a thermally conductive EMI absorber includes a matrix and at least one functional filler in the matrix. In this example, the at least one functional filler includes or consists essentially of silicon carbide and alumina. And, the matrix includes or consists essentially of a process oil, a diblock polymer, a coupling agent, an antioxidant, and silica. Continuing with this example, the thermally conductive EMI absorber includes at least 90% by weight (e.g., at least 94.5% by weight, etc.) of at least one functional filler (silicon carbide and alumina) and no more than 6% by weight (e.g., no more than 5.5% by weight, etc.) of the matrix. Additionally, the thermally conductive EMI absorber includes at least 80% by volume of the at least one functional filler (silicon carbide and alumina) and less than 20% by volume of the matrix. For example, the thermally conductive EMI absorber may include about 69% to about 74% by weight silicon carbide, about 20% to about 25% by weight alumina, about 2.5% to about 5% by weight process oil, about 0.3% to about 0.7% by weight diblock polymer, about 0.2% to about 0.6% by weight coupling agent, about 0.5% to about 0.9% by weight silica, and less than about 0.1% by weight antioxidant. The thermally conductive EMI absorber has a thermal conductivity of at least 11 W / mK (e.g., 11 W / mK, 12 W / mK, greater than 12 W / mK, etc.). The thermally conductive EMI absorber has an attenuation of greater than 15 decibels per centimeter (dB / cm) at frequencies of 10 gigahertz (GHz) or higher, greater than 34 dB / cm at frequencies of 20 GHz or higher, greater than 66 dB / cm at frequencies of 40 GHz or higher, and greater than 90 dB / cm at frequencies of 60 GHz or higher. The thermally conductive EMI absorber has a hardness of about 58 Shore 00 or less at three seconds and a hardness of about 37 Shore 00 or less at thirty seconds. The thermally conductive EMI absorber is dielectric and not conductive. The thermally conductive EMI absorber does not include silicone and is silicone-free, so that the thermally conductive EMI absorber can be used without silicone migration. The thermally conductive EMI absorber is configured as a gap filling pad, a phase change material, a putty, a grease, or a sheet.

[0122] As an example, Tables 1 and 2 below include example properties that a thermally conductive EMI absorber may have in an example embodiment. As shown in Table 1 below, an example embodiment of a thermally conductive EMI absorber may have a thermal conductivity of at least about 12 Watts per meter-Kelvin (W / mK), a density of about 3 grams per cubic centimeter (g / cc), a hardness of about 58 Shore 00 or less at three seconds, a hardness of about 37 Shore 00 or less at thirty seconds, a deflection of about 9.6% at 38 kPa on a 1 mm thick sample, a deflection of about 34.4% at 345 kPa on a 1 mm thick sample, an operating temperature range of about -40°C to about 125°C, etc.

[0123] As shown in Table 2 below, another exemplary embodiment of the thermally conductive EMI absorber may have a thermal conductivity of at least about 11.5 W / mK, a density of about 2.96 g / cc, a hardness of about 58 Shore 00 or less at three seconds, a hardness of about 31 Shore 00 or less at thirty seconds, a deflection of about 76% at 10 pounds per square inch (psi) on a 1 mm thick sample, a deflection of about 39% at 50 psi on a 1 mm thick sample, an operating temperature range of about -40°C to about 125°C, etc. In addition, the thermally conductive EMI absorber may also be lead-free, REACH and ROHS compliant, and have a UL flammability rating of UL V-0. As also shown in Table 2, the thermally conductive EMI absorber may have the following electromagnetic properties: 22 dB / cm attenuation at 10 GHz, 39 dB / cm attenuation at 20 GHz, 53 dB / cm attenuation at 28 GHz, 76 dB / cm attenuation at 39 GHz, and 135 dB / cm attenuation at 77 GHz.

[0124] The thermal conductivities disclosed in Tables 1 and 2 below, as well as other thermal conductivities disclosed herein, were determined by a Hot Disk thermal constant analyzer. In other exemplary embodiments, the thermally conductive EMI absorber may be configured differently, such as having one or more properties different from those provided in Tables 1 and 2 (e.g., a thermal conductivity of at least 6 W / mK, a thermal conductivity of about 11 W / mK, etc.), etc.

[0125] Table 1

[0126] nature data Test Method color Dark Gray Vision Thermal conductivity 12W / mK Hot Disk Thermal Constant Analyzer Density g / cc 3 ASTM D792 Hardness 3 seconds 58 Xiao 00 ASTM D2240 Hardness 30 seconds 37 Xiao 00 ASTM D2240 Deflection at 138 kPa on 1 mm 9.6％ ASTM D575 Deflection at 345kPa on 1mm 34.4％ ASTM D575 Temperature range -40℃ to 125℃ N / A Volume resistivity <![CDATA[6x10 13 Ohm*cm]]> ASTM D257 DC breakdown voltage at 2.5mm 1.3kV ASTM D149 AC breakdown voltage at 2.5mm 1.6kV ASTM D149 Standard thickness range 0.5mm to 5mm Condensation and fogging at 120°C No in 96 hours

[0127] Table 2

[0128] nature data Test Method color Dark Gray Vision Thermal conductivity 11.5W / mK Hot Disk Thermal Constant Analyzer Density g / cc 2.96 ASTM D792 Hardness 3 seconds 58 Xiao 00 ASTM D2240 Hardness 30 seconds 31 Xiao 00 ASTM D2240 Deflection at 10 psi on 1 mm 7％ ASTM D575 Deflection at 50 psi on 1 mm 39％ ASTM D575 Temperature range -40℃ to 125℃ N / A UL Flammability UL94 V-0 Volume resistivity <![CDATA[6x10 16 Ohm*cm]]> ASTM D257 Exhaust (TML) 0.29％ ASTM E595-07 Exhaust (CVCM) 0.14％ ASTM E595-07 DC breakdown voltage at 2.5mm 1.85kV ASTM D149 AC breakdown voltage at 2.5mm 1.34kV ASTM D149 Standard thickness range 0.5mm to 4mm Condensation and fogging at 120°C No in 96 hours Attenuation at 10 GHz 22dB / cm Attenuation at 20 GHz 39dB / cm Attenuation at 28 GHz 53dB / cm Attenuation at 39 GHz 76dB / cm Attenuation at 77 GHz 135dB / cm

[0129] In an exemplary embodiment, the thermally conductive EMI absorber may include a silicone-free hybrid absorber / thermal management material having an ultra-high thermal conductivity of at least 11 W / mK (e.g., 11.5 W / mK, 12 W / mK, etc.). The thermally conductive EMI absorber may be used similarly to conventional thermal interface materials between a heat source (e.g., a high-power integrated circuit (IC), an optical transceiver, a 5G infrastructure device, etc.) and a heat dissipation / heat transfer device (e.g., a heat sink, a metal chassis, other heat removal structures, etc.). The thermally conductive EMI absorber is also used to suppress unwanted energy coupling, resonance, or surface currents (which may otherwise cause board-level EMI issues).

[0130] Exemplary embodiments of thermally conductive EMI absorbers disclosed herein may include or provide one or more (but not necessarily any or all) of the following advantages or features, such as:

[0131] ● Very high thermal conductivity to meet the industry trend of increasing IC power;

[0132] ●Good EMI suppression in a wide frequency range, such as over 25GHz, over 60GHz, etc.;

[0133] ●Silicone-free formulations suitable for silicone-sensitive applications;

[0134] ●Inherent surface stickiness;

[0135] ● comply with minimal or at least reduced component stresses during assembly;

[0136] ● Space-saving solution and performance advantages from the dual-functional properties of thermal conductivity and EMI reduction;

[0137] Improved reliability performance of electronic products, such as better signal integrity due to EMI reduction, consistent performance of electronic products due to the temperature stability and low outgassing properties of the products;

[0138] Improved electromagnetic compatibility (EMC) performance to meet compliance requirements;

[0139] ● Passed UL94 V-0 requirements; and

[0140] ●Environmentally friendly solutions that meet regulatory requirements including RoHS and REACH.

[0141] In an exemplary embodiment, the thermally conductive EMI absorber provides a dual-use, single product solution that can be used in a wide range of industries and applications, such as applications involving ADAS (advanced driver assistance systems) radar, high-speed data transmission, microwave transmission, satellite, space, cancer detection and treatment, wireless high-speed connectivity, 5G millimeter wave technology, SSR (split ring resonator) technology, optical transceivers, etc.

[0142] In an exemplary embodiment, the thermally conductive EMI absorber can be provided as a sheet that is 18 inches by 18 inches and has a thickness ranging from about 0.02 inches to about 0.16 inches or about 0.5 mm to about 4 mm. For example, the thermally conductive EMI absorber can be provided at a thickness of about 0.02 inches, 0.03 inches, 0.04 inches, 0.06 inches, 0.08 inches, etc.

[0143] In an exemplary embodiment, a thermally conductive EMI absorber may be used to define or provide a portion of a thermally conductive heat path from a heat source to a heat removal / heat dissipation structure or component. For example, a thermally conductive EMI absorber may be used to help conduct thermal energy (e.g., heat, etc.) away from a heat source of an electronic device. The thermally conductive EMI absorber may be positioned generally between a heat source and a heat removal / heat dissipation structure or component (e.g., in direct physical contact therewith, in thermal contact therewith, etc.) to establish a thermal joint, interface, passage, or thermally conductive heat path that may transfer (e.g., conduct) heat from the heat source to the heat removal / heat dissipation structure or component. During operation, the thermally conductive EMI absorber may be used to allow heat to be transferred (e.g., conduct heat, etc.) from the heat source to the heat removal / heat dissipation structure or component along a thermally conductive path. The thermally conductive EMI absorber may also be operable to mitigate EMI incident on the thermally conductive EMI absorber (e.g., absorb EMI, etc.).

[0144] In an exemplary embodiment, an electronic device includes a heat source and a thermally conductive EMI absorber as disclosed herein. The thermally conductive EMI absorber is positioned relative to the heat source for establishing a thermally conductive heat path from the heat source.

[0145] In an exemplary embodiment, an electronic device includes a heat source, a heat removal / heat dissipation structure, and a thermally conductive EMI absorber as disclosed herein. The thermally conductive EMI absorber is between the heat source and the heat removal / heat dissipation structure.

[0146] In an exemplary embodiment, an electronic device includes a heat source, an EMI shield, and a thermally conductive EMI absorber as disclosed herein. The thermally conductive EMI absorber is between the heat source and the EMI shield. The electronic device may also include a heat removal / heat dissipation device and a thermal interface material between the EMI shield and the heat removal / heat dissipation device. The heat source may be an integrated circuit. The EMI shield may be a plate shield. The heat removal / heat dissipation structure may be a heat sink. The thermal interface material may be between the plate shield and the heat sink to establish a thermally conductive heat path from the plate shield to the heat sink. The thermally conductive EMI absorber may be between the integrated circuit and the plate shield to establish a thermally conductive heat path from the integrated circuit to the plate shield and to suppress the radiated electromagnetic field coupling between the integrated circuit and the heat sink.

[0147] The example embodiments disclosed herein may be used with a wide range of heat sources, electronic devices, and / or heat removal / dissipation structures or components (e.g., radiators, heat sinks, heat pipes, steam chambers, device housings, housings, or chassis, etc.). For example, a heat source may include one or more heat generating components or devices, such as high-power integrated circuits (ICs), optical transceivers, 5G infrastructure devices (e.g., base stations, small cells, smart poles, etc.), 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, tube cores in bottom fill, semiconductor devices, flip-chip devices, graphics processing units (GPUs), digital signal processors (DSPs), multi-processor systems, integrated circuits (ICs), multi-core processors, etc.). In general, a heat source may include any component or device that has a temperature higher than a thermally conductive EMI absorber or that provides or transfers heat to a thermally conductive EMI absorber, regardless of whether the heat is generated by the heat source or is transferred only by or via the heat source. Therefore, 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.

[0148] Example embodiments are provided so that the present disclosure will be thorough, and the scope will be fully conveyed to those skilled in the art. A large number of specific details, such as examples of specific parts, devices, and methods, are set forth to provide a thorough understanding of the embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be adopted, the example embodiments can be implemented in many different forms, and no content should be interpreted as limiting the scope of the present disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. In addition, the advantages and improvements that can be achieved with one or more exemplary embodiments of the present invention are provided only for illustrative purposes, and do not limit the scope of the present disclosure (because the exemplary embodiments disclosed herein can provide all or none of the above-mentioned advantages and improvements, and still fall within the scope of the present disclosure).

[0149] The specific dimensions, specific materials and / or specific shapes disclosed herein are examples in nature, and do not limit the scope of the present disclosure. The disclosure of the specific value and specific value range for a given parameter here is not the exhaustion of other values ​​and value ranges that can be used for one or more of the examples disclosed here. Moreover, it is envisioned that any two specific values ​​for the specific parameters narrated here can limit the endpoints of the value range that can be suitable for the given parameter (that is, the disclosure of the first value and the second value for a given parameter can be interpreted as disclosure that can also adopt any value between the first and second values ​​for a given parameter). For example, if parameter X is exemplified as having value A and also exemplified as having value Z here, it is envisioned that parameter X can have a value range from about A to about Z. Similarly, it is envisioned that the disclosure of two or more value ranges (regardless of whether such ranges are nested, overlapped or different) for a parameter includes all possible combinations of the value ranges that can be clamped using the endpoints of the disclosed range. For example, if parameter X is illustrated herein as having values ​​within the range 1-10 or 2-9 or 3-8, it is also contemplated that parameter X may have other value ranges including 1-9, 1-8, 1-3, 1-2, 2-10, 2-8, 2-3, 3-10, and 3-9.

[0150] The terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. As used herein, the singular forms "one" and "an" may be intended to also include plural forms, unless the context clearly indicates otherwise. The terms "including" and "having" are inclusive, and therefore specify the presence of the described features, integers, steps, operations, elements and / or parts, but do not exclude the presence or increase of one or more other features, integers, steps, operations, elements, parts and / or their groups. The method steps, processes and operations described herein are not to be interpreted as necessarily requiring their execution in the particular order discussed or illustrated, unless specifically identified as an execution order. It is also to be understood that additional or alternative steps may be adopted.

[0151] When an element or layer is referred to as being "on," "engaged," "connected," or "coupled" to another element or layer, the element or layer may be directly on, directly engaged, connected, or coupled to another element or layer, or intervening elements or layers may be present. Conversely, when an element is referred to as being "directly on," "directly engaged," "directly connected," or "directly coupled" to another element or layer, no intervening elements or layers may be present. Other words used to describe relationships between elements should be interpreted in the same manner (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.

[0152] The term "approximately" when applied to a value indicates that the calculation or measurement allows for slight imprecision in the value (close to exact in value; approximately or reasonably close to a value; nearly). If for some reason the imprecision provided by "approximately" is not otherwise understood in the art in this ordinary sense, then "approximately" as used herein indicates at least the variation that may result from ordinary measurement methods or use of such parameters. For example, the terms "substantially," "about," and "roughly" may be used herein to mean within manufacturing tolerances. Whether or not modified by the term "approximately," the claims include equivalents to the quantities.

[0153] Although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts here, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or part from another region, layer or part. Terms such as "first", "second" and other numerical terms do not imply order when used here, unless the context clearly indicates. Thus, the first element, component, region, layer or part discussed below can be referred to as the second element, component, region, layer or part without departing from the teaching of the example embodiments.

[0154] Spatially relative terms (such as "inside", "outside", "below", "below", "down", "above", "upper", etc.) can be used here for ease of description to describe the relationship of one element or feature to another element or feature as illustrated in the drawings. Spatially relative terms may be intended to include different orientations of the device in use or operation in addition to the orientations depicted in the drawings. For example, if the device in the drawings is flipped, the elements described as "below" or "below" other elements or features will be oriented to be "above" other elements or features. Thus, the example term "below" can include both the above and below orientations. The device can be oriented in other ways (rotated 90 degrees or in other orientations), so the spatially relative descriptors used here are interpreted.

[0155] The foregoing description of the embodiments has been provided for the purpose of illustration and description. It is not intended to be exhaustive or to limit the present disclosure. The independent elements, intended or described uses or features of a particular embodiment are generally not limited to that particular embodiment, but are interchangeable where appropriate and can be used in a selected embodiment (even if the embodiment is not specifically shown or described). The same content can also be changed in many ways. Such changes are not considered to be deviations from the present disclosure, and all such modifications are intended to be included within the scope of the present disclosure.

Claims

1. A thermally conductive EMI absorber comprising a matrix and at least one functional filler in the matrix, wherein: The thermally conductive EMI absorber has a thermal conductivity greater than 6 Watts per meter per Kelvin (W / mK); and The thermally conductive EMI absorber has an attenuation of at least 22 decibels per centimeter (dB / cm) at a frequency of 10 gigahertz (GHz).

2. The thermally conductive EMI absorber of claim 1, wherein: The thermally conductive EMI absorber has a thermal conductivity of at least 11 W / mK.

3. The thermally conductive EMI absorber of claim 1, wherein: The thermally conductive EMI absorber has a thermal conductivity of at least 11.5 W / mK.

4. The thermally conductive EMI absorber of claim 1, wherein: The thermally conductive EMI absorber has a thermal conductivity of at least 12 W / mK.

5. The thermally conductive EMI absorber according to any one of claims 1 to 4, wherein: The thermally conductive EMI absorber has: Attenuation greater than 34 dB / cm at frequencies of at least 20 GHz; Attenuation greater than 66 dB / cm at frequencies of at least 40 GHz; and Attenuation greater than 90 dB / cm at frequencies of at least 60 GHz.

6. The thermally conductive EMI absorber according to any one of claims 1 to 4, wherein: The thermally conductive EMI absorber has: Attenuation of at least 39dB / cm at a frequency of 20GHz; At least 53dB / cm attenuation at 28GHz; Attenuation of at least 76 dB / cm at 39 GHz; and At least 135dB / cm attenuation at 77GHz.

7. The thermally conductive EMI absorber of claim 6, wherein: The thermally conductive EMI absorber has a thermal conductivity of at least 11.5 W / mK.

8. The thermally conductive EMI absorber of claim 7, wherein: The thermally conductive EMI absorber has a hardness of no greater than 58 Shore 00 at three seconds and a hardness of no greater than 37 Shore 00 at thirty seconds; The thermally conductive EMI absorber has a UL flammability rating of UL V-0; The thermally conductive EMI absorber is dielectric rather than conductive; and The thermally conductive EMI absorber does not include silicone, is completely silicone-free, and / or is capable of being used without silicone migration.

9. The thermally conductive EMI absorber of any one of claims 1 to 4, wherein: The thermally conductive EMI absorber comprises at least 90% by weight of the at least one functional filler; and the thermally conductive EMI absorber comprises less than 10% by weight of the matrix; and / or The thermally conductive EMI absorber includes at least 80% by volume of the at least one functional filler, and the thermally conductive EMI absorber includes less than 20% by volume of the matrix.

10. The thermally conductive EMI absorber of any one of claims 1 to 4, wherein: The matrix comprises a thermoreversible oleogel; and / or The matrix comprises a block copolymer and a process oil, The matrix comprises a diblock copolymer and / or a triblock copolymer.

11. The thermally conductive EMI absorber of any one of claims 1 to 4, wherein: The matrix includes a process oil and a block copolymer without chemical cross-linking such that the thermally conductive EMI absorber is a thermally reversible thermoplastic material.

12. The thermally conductive EMI absorber of any one of claims 1 to 4, wherein: The at least one functional filler includes one or more of zinc oxide, silicon carbide, carbonyl iron, aluminum oxide, aluminum nitride, aluminum, boron nitride, silicon nitride, iron, graphite, ferrite, aluminum hydroxide and / or silica.

13. The thermally conductive EMI absorber of any one of claims 1 to 4, wherein: The at least one functional filler consists of carbonyl iron, silicon carbide, zinc oxide, aluminum nitride and aluminum oxide; or The at least one functional filler consists of zinc oxide, silicon carbide and aluminum nitride; or The at least one functional filler consists of silicon carbide and aluminum oxide.

14. The thermally conductive EMI absorber of any one of claims 1 to 4, wherein: The matrix includes process oil, diblock polymer, coupling agent and silica.

15. The thermally conductive EMI absorber of any one of claims 1 to 4, wherein: The matrix includes paraffin process oil, styrene-ethylene-propylene (SEP) linear polymer with a diblock structure and a coupling agent.

16. The thermally conductive EMI absorber of any one of claims 1 to 4, wherein: The matrix includes a non-silicone polymer matrix.

17. The thermally conductive EMI absorber of claim 16, wherein: The non-silicone polymer matrix comprises a non-silicone oil gel resin, and / or wherein the non-silicone polymer matrix comprises: Styrene and ethylene / butylene copolymers; and / or Styrene and ethylene / propylene copolymers.

18. The thermally conductive EMI absorber of any one of claims 1 to 4, wherein: The matrix includes a process oil, a diblock polymer, and a coupling agent; and The at least one functional filler includes silicon carbide.

19. The thermally conductive EMI absorber of claim 18, wherein: The at least one functional filler further comprises aluminum oxide; or The at least one functional filler further comprises zinc oxide, carbonyl iron, aluminum nitride and aluminum oxide; or The at least one functional filler further comprises zinc oxide and aluminum nitride.

20. The thermally conductive EMI absorber of any one of claims 1 to 4, wherein: The thermally conductive EMI absorber has a UL flammability rating of UL V-0; The thermally conductive EMI absorber is dielectric rather than conductive; and The thermally conductive EMI absorber does not include silicone, is completely silicone-free, and / or is capable of being used without silicone migration.

21. The thermally conductive EMI absorber of any one of claims 1 to 4, wherein: The at least one functional filler comprises zinc oxide, silicon carbide and aluminum nitride; The matrix includes paraffin process oil, styrene-ethylene-propylene (SEP) linear polymer with a diblock structure, and a coupling agent; The thermally conductive EMI absorber comprises at least 93% by weight of the at least one functional filler and no more than 7% by weight of the matrix; and The thermally conductive EMI absorber includes at least 81% by volume of the at least one functional filler and no more than 19% by volume of the matrix.

22. The thermally conductive EMI absorber of claim 21, wherein: The thermally conductive EMI absorber includes 1.5% to 2% by weight of zinc oxide, 16% to 19% by weight of aluminum nitride, 70% to 80% by weight of silicon carbide, 4% to 6% by weight of paraffin process oil, 0.4% to 0.8% by weight of styrene-ethylene-propylene (SEP) linear polymer having a diblock structure, and 0.5% to 1% by weight of a coupling agent.

23. The thermally conductive EMI absorber of any one of claims 1 to 4, wherein: The at least one functional filler comprises carbonyl iron, silicon carbide, zinc oxide, aluminum nitride and aluminum oxide; The matrix includes paraffin process oil, styrene-ethylene-propylene (SEP) linear polymer with a diblock structure, and a coupling agent; The thermally conductive EMI absorber comprises at least 95% by weight of the at least one functional filler and no more than 10% by weight of the matrix; and The thermally conductive EMI absorber includes at least 83% by volume of the at least one functional filler and no more than 17% by volume of the matrix.

24. The thermally conductive EMI absorber of claim 23, wherein: The thermally conductive EMI absorber includes 23% to 29% by weight of carbonyl iron, 0.8% to 1.2% by weight of zinc oxide, 5% to 5.7% by weight of aluminum nitride, 58% to 67% by weight of silicon carbide, 16% to 21% by weight of alumina, 3% to 5% by weight of paraffin process oil, 0.3% to 0.7% by weight of styrene-ethylene-propylene (SEP) linear polymer having a diblock structure, and 0.4% to 0.6% by weight of a coupling agent.

25. The thermally conductive EMI absorber of any one of claims 1 to 4, wherein: The at least one functional filler comprises zinc oxide, silicon carbide and aluminum nitride; The matrix includes paraffin process oil, styrene-ethylene-butylene-styrene SEBS linear polymer with a triblock structure, styrene-ethylene-propylene SEP linear polymer with a diblock structure and a coupling agent; The thermally conductive EMI absorber comprises at least 93% by weight of the at least one functional filler and no more than 7% by weight of the matrix; and The thermally conductive EMI absorber includes at least 81% by volume of the at least one functional filler and no more than 19% by volume of the matrix.

26. The thermally conductive EMI absorber of claim 25, wherein: The thermally conductive EMI absorber includes 1.5% to 2% by weight of zinc oxide, 16% to 19% by weight of aluminum nitride, 70% to 80% by weight of silicon carbide, 4% to 6% by weight of paraffin process oil, 0.2% to 0.4% by weight of styrene-ethylene-butylene-styrene SEBS linear polymer with a triblock structure, 0.2% to 0.4% by weight of styrene-ethylene-propylene SEP linear polymer with a diblock structure, and 0.5% to 1% by weight of a coupling agent.

27. The thermally conductive EMI absorber of any one of claims 1 to 4, wherein: The at least one functional filler comprises carbonyl iron, silicon carbide, zinc oxide, aluminum nitride and aluminum oxide; The matrix includes paraffin process oil, styrene-ethylene-butylene-styrene SEBS linear polymer with a triblock structure, styrene-ethylene-propylene SEP linear polymer with a diblock structure and a coupling agent; The thermally conductive EMI absorber comprises at least 95% by weight of the at least one functional filler and no more than 5% by weight of the matrix; and The thermally conductive EMI absorber includes at least 83% by volume of the at least one functional filler and no more than 17% by volume of the matrix.

28. The thermally conductive EMI absorber of claim 27, wherein: The thermally conductive EMI absorber includes 23% to 29% by weight of carbonyl iron, 0.8% to 1.2% by weight of zinc oxide, 5% to 5.7% by weight of aluminum nitride, 58% to 67% by weight of silicon carbide, 16% to 21% by weight of alumina, 3% to 5% by weight of paraffin process oil, 0.2% to 0.4% by weight of styrene-ethylene-butylene-styrene SEBS linear polymer with a triblock structure, 0.1% to 0.3% by weight of styrene-ethylene-propylene SEP linear polymer with a diblock structure, and 0.4% to 0.6% by weight of a coupling agent.

29. The thermally conductive EMI absorber of any one of claims 1 to 4, wherein: The at least one functional filler comprises silicon carbide and aluminum oxide; The matrix includes a process oil, a diblock polymer, a coupling agent, an antioxidant and silica; The thermally conductive EMI absorber comprises at least 94.5% by weight of the at least one functional filler and no more than 5.5% by weight of the matrix; and The thermally conductive EMI absorber includes at least 80% by volume of the at least one functional filler and no more than 20% by volume of the matrix.

30. The thermally conductive EMI absorber of claim 29, wherein: The thermally conductive EMI absorber includes 69% to 74% by weight of silicon carbide, 20% to 25% by weight of alumina, 2.5% to 5% by weight of process oil, 0.3% to 0.7% by weight of a diblock polymer, 0.2% to 0.6% by weight of a coupling agent, 0.5% to 0.9% by weight of silica, and less than 0.1% by weight of an antioxidant.

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