Reducing migration of materials from thermal management and / or electromagnetic interference (EMI) mitigation materials

Abstract

The present disclosure relates to reducing migration of materials from thermal management and / or electromagnetic interference (EMI) mitigation materials (e.g., thermal interface materials (TIMs), EMI absorbers, thermally conductive EMI absorbers, conductive elastomers (ECEs), conductive composites, combinations thereof, etc.) and other polymer-inorganic composites for other purposes. In an exemplary embodiment, a method includes adding halloysite and / or hollow nano-tubular inorganic structures and / or tubular inorganic nanomaterials to the composite in an amount sufficient to reduce migration of the material from the composite. Also disclosed are exemplary embodiments of the composite comprising halloysite and / or hollow nanotube inorganic structures and / or tubular inorganic nanomaterials in an amount sufficient to reduce migration of the material from the composite.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the priority and benefit of U.S. Provisional Patent Application No. 63 / 415,915, filed on October 13, 2022, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to reducing the migration of materials from thermal management and / or electromagnetic interference (EMI) mitigation materials (e.g., thermal interface materials (TIMs), EMI absorbers, thermally conductive EMI absorbers, electrically conductive elastomers (ECEs), electrically conductive composites, combinations thereof, etc.) and other polymer - inorganic composites for other purposes. Background Art

[0004] This section provides background information related to the present disclosure, which is not necessarily prior art.

[0005] Electrical components such as semiconductors, integrated circuit packages, transistors, etc. typically have a pre - designed temperature at which they operate optimally. Ideally, the pre - designed temperature is 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 may operate at temperatures significantly higher than their normal or desired operating temperatures. Such high temperatures can adversely affect the operating characteristics of the electrical components and the operation of related devices.

[0006] To avoid or at least reduce the adverse operating characteristics resulting from heat generation, heat should be removed, for example, by conducting 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 between the electrical component and heat sink surfaces via an intermediate medium or thermal interface material (TIM). Compared to filling the gap with air (a relatively poor heat conductor), a thermal interface material can be used to fill the gap between the heat transfer surfaces to increase the heat transfer efficiency.

[0007] In addition, a common problem in the operation of electronic devices is the generation of electromagnetic radiation within the electronic circuits of the device. Such 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.

[0008] Common solutions for reducing EMI / RFI effects are by using shields that can absorb and / or reflect and / or redirect EMI energy. These shields are typically used to contain EMI / RFI within its source and isolate other devices in proximity to the EMI / RFI source. These shields can be made of metal, polymer-inorganic composites, foams filled with or wrapped or coated with absorbent and / or reflective materials, etc.

[0009] As used herein, the term "EMI" shall be considered to generally include and refer to both EMI emissions and RFI emissions, and the term "electromagnetic" shall be considered to generally include and refer to electromagnetic frequencies and radio frequencies from both external and internal sources. Thus, the term shield (as used herein) broadly includes and refers to reducing (or limiting) EMI and / or RFI, such as by absorbing, reflecting, blocking, and / or redirecting energy or some combination thereof, such that the EMI and / or RFI no longer interfere, for example, with the government compliance and / or internal functions of an electronic component system.

[0010] If the above-mentioned reducing materials are not made of metal, they are typically made of inorganic-polymer composites or metal-polymer composites. The concentration of the inorganic material, which is usually in particulate form, in the polymer matrix is typically high to achieve the desired control of thermal and / or EMI problems. In some cases, the composites are used in applications where they are compressed between two parts of a device that requires management of thermal and / or EMI problems. This compression can occur during the assembly of the device or during compression and expansion cycles during the use of the device. Thus, the composites must be "soft" so that they can easily deflect and absorb the compressive forces without transferring these forces to the protected device, thereby posing a related risk of physical damage. As is known to those skilled in the art, in some cases, the methods used to prepare such soft composites result in materials that migrate out various organic substances over time, especially after repeated cycles of compression and expansion. These organic substances can consist of polymers, monomers, additives used to form the composites or enhance their performance during use, complexes of organic and inorganic materials, etc. The term "oil bleeding" is typically used in the industry to describe this phenomenon and will be used in this document, understanding that "oil" refers to a range of mainly organic substances and "bleeding" refers to the movement of materials from inside the composite to one or more locations outside the composite. Brief Description of the Drawings

[0011] The drawings described herein are for illustrative purposes only for the selected embodiments and not for all possible implementations and are not intended to limit the scope of the present disclosure.

[0012] Figure 1An exemplary embodiment is shown where a first thermal management and / or electromagnetic interference (EMI) mitigation material (e.g., a thermally conductive EMI absorber, etc.) is positioned between a board-level shield and an integrated circuit or chip. Figure 1 A second thermal management and / or electromagnetic interference (EMI) mitigation material (e.g., a thermally conductive pad, other thermal interface materials, etc.) between a heat sink and the board-level shield is also shown.

[0013] Figure 2 An exemplary thermal gap filler comprising a ceramic-filled silicone sheet according to an exemplary embodiment of the present disclosure is shown. Halloysite or other tubular nanomaterials / hollow nanotubular additives (e.g., imogolite, Saudi halloysite-like nanotubes, etc.) can be added to the ceramic-filled silicone sheet in an amount sufficient (e.g., less than about 10 wt%, about 5 wt% to 10 wt%, about 0.1 wt% to 2 wt%, about 1 wt%, etc.) to reduce material migration from the thermal gap filler (e.g., silicone oil exudate, etc.). In such an exemplary embodiment, the thermal gap filler including the halloysite additive can be configured to have a high thermal conductivity (e.g., above about 4 W / mK, etc.), low pressure relative to deflection, and excellent surface wetting for low contact resistance. The thermal gap filler can also conform to minimize or at least reduce board and component stresses during assembly. The thermal gap filler can be suitable for large tolerance applications. And the thermal gap filler can comply with REACH and ROHS and / or have a UL flammability rating of UL V-0.

[0014] Figure 3 Exemplary properties that a thermal gap filler comprising a ceramic-filled silicone sheet according to an exemplary embodiment of the present disclosure can have, the ceramic-filled silicone sheet including halloysite or other tubular nanomaterials / hollow nanotubular additives. In other exemplary embodiments, the thermal gap filler can be configured differently, e.g., having one or more properties different from those Figure 3 provided (e.g., a thermal conductivity greater than or less than 4 W / mK, etc.).

[0015] Figure 4 is a graph of the percentage of deflection in pounds per square inch (PSI) versus pressure for a thermal gap filler comprising a ceramic-filled silicone sheet according to an exemplary embodiment of the present disclosure, the ceramic-filled silicone sheet including halloysite or other tubular nanomaterials / hollow nanotubular additives. Five thermal gap filler samples have different sheet thicknesses of 40 mils, 60 mils, 140 mils, 180 mils, and 200 mils. The ceramic-filled silicone sheet includes an amount of halloysite additive sufficient to reduce material migration from the thermal gap filler (e.g., silicone oil exudate, etc.).

[0016] Figure 5 The thermal resistance in degrees Celsius-inch squared per watt (°C-in² / W) that a thermal gap filler comprising a ceramic-filled silicone sheet according to an exemplary embodiment of the present disclosure can have, relative to pressure in pounds per square inch (PSI), 2 The ceramic-filled silicone sheets include halloysite or other tubular nanomaterials / hollow nanotubular additives. Four thermal gap filler samples have different sheet thicknesses of 40 mils, 60 mils, 80 mils, and 100 mils. The ceramic-filled silicone sheets include halloysite additives in an amount sufficient to reduce migration of material (e.g., silicone oil exudate, etc.) from the thermal gap filler. DETAILED DESCRIPTION

[0017] Exemplary embodiments will now be described more fully with reference to the accompanying drawings.

[0018] Disclosed herein are innovative methods for reducing migration of materials (e.g., silicone oil exudate, etc.) from thermal management and / or electromagnetic interference (EMI) mitigation materials (e.g., thermal interface materials (TIM), EMI absorbers, thermally conductive EMI absorbers, conductive elastomers (ECE), conductive composites, combinations thereof, etc.) and other polymer-inorganic composites for other purposes.

[0019] Oil exudation is a problem due to aesthetic reasons and due to potential contamination of optical devices in electronic applications (e.g., optical transceivers, camera lenses, etc.). High-speed signal lines can also be affected by oil exudation. Thus, it is desirable to reduce and / or prevent migration of materials (e.g., silicone oil exudate) from polymer-inorganic composites used to mitigate thermal and / or EMI problems in devices. It is also desirable to reduce migration of materials while minimizing or insignificantly altering other desired properties of the composite.

[0020] However, the preparation of high-loading polymer composites that serve as thermal management and / or electromagnetic interference (EMI) mitigation materials, which have the ability to meet desired mitigation requirements and other requirements while also being prone to deflection under low levels of applied force, is challenging. In these materials, oil leakage can occur due to a variety of reasons. For example, conventional thermal management and / or electromagnetic interference (EMI) mitigation materials are typically based on the use of silicone polymers. Silicone polymers generally contain polymers with a wide molecular weight (MW) distribution. It is generally assumed that some of the polymers with low molecular weight can migrate in the matrix to such an extent that the migrated polymer material becomes visible outside the scope of the composite, resulting in undesired aesthetics. In addition to silicone polymers, other additives in the composite, such as dispersants, stabilizers (e.g., UV stabilizers, heat stabilizers, etc.), can also migrate. Composites using polymers that are not silicone-based materials also contain substances that can migrate and face similar challenges as described above for representative silicone-based systems.

[0021] After recognizing the above, innovative methods have been developed and / or disclosed herein that address the problem of how to prepare high-loading polymer composites that have the ability to be prone to deflection under low levels of applied force and do not have undesired migration or seepage of materials from the composite into the surrounding area. It is envisioned that tubular nanomaterials / hollow nanotubular additives, such as halloysite, imogolite, Saudi halloysite-like nanotubes, etc., can provide a method for reducing the migration of more mobile materials in the composite by preferentially adsorbing or reacting with those materials inside the nanotubes without unwanted interactions with the bulk matrix of the composite, such as hardening. Those skilled in the art will understand that these nanomaterials can be treated to modify their surfaces to provide compatibility with various matrices, and these variations are included in the definition of these materials.

[0022] As disclosed herein, exemplary embodiments include reducing the migration of materials by using halloysite clay as a thermal management and / or electromagnetic interference (EMI) mitigation material (e.g., thermal interface material, EMI absorber, thermally conductive EMI absorber, conductive elastomer (ECE), conductive composite, combinations thereof, etc.) and an additive for other polymer-inorganic composites for other purposes. In an exemplary embodiment, halloysite is added in an amount sufficient such that the resulting thermal management and / or electromagnetic interference (EMI) mitigation material has the following advantageous characteristics: reduced or undetectable exudation compared to a thermal management and / or electromagnetic interference (EMI) mitigation material with the same formulation but without halloysite. In some cases, the addition of the clay can also result in a lower force required for deflection and can provide improved thixotropy.

[0023] For comparison purposes, an oil absorbent material was added to the TIM pad formulation. Then, the TIM pad with the oil absorbent material was compared to a TIM pad with the same formulation but without the oil absorbent material. The different oil absorbents added to the TIM pad formulation included talc, corn starch, alumina fiber, kaolin, and halloysite. It was observed that the performance of the talc, corn starch, alumina fiber, and kaolin absorbents was not as good as that of halloysite. In particular, halloysite resulted in significantly less oil exudate leaking from the TIM pad, while also improving or at least maintaining substantially the same deflection properties of the TIM pad. This observation is particularly notable because kaolin and halloysite clays have similar chemical compositions: they differ in the physical structure of the clay particles. It is recognized that the unique nanotube structure of halloysite may allow for the absorption of free-moving polymers that would otherwise separate and migrate from the bulk material.

[0024] Compared to a TIM with a halloysite additive, a TIM with the same formulation but without the halloysite additive has a significantly greater tendency to exude, which can lead to aesthetic and performance issues in electronic applications. Although there are conventional methods for reducing TIM exudation, it has generally been found that such conventional methods significantly increase hardness, such that the harder TIMs are not able to deflect easily under low levels of applied force. Accordingly, exemplary embodiments are disclosed herein in which halloysite and / or other tubular nanomaterials / hollow nanotubular additives are added to formulations for thermal management and / or electromagnetic interference (EMI) mitigation materials to reduce exudation and increase flexibility without detrimentally altering other desirable properties of the thermal management and / or EMI mitigation materials.

[0025] Experimental results have shown the positive effects of adding 0.2 weight percent (wt%) and 0.5 wt% halloysite to a formulation for a silicone-based thermal gap filler pad. Adding 0.5 wt% halloysite to the formulation resulted in a silicone-based thermal gap filler pad having improved lower deflection force and reduced exudation to an undetectable amount. Microscopic analysis showed the presence of halloysite particles in the matrix. In contrast, when 0.5 wt% of kaolin was added to the same formulation for a silicone-based thermal gap filler pad, the same improvements were not observed.

[0026] As background, kaolin and halloysite have the same composition but different structures. More specifically, halloysite contains hollow nanotubular structures or tubular nanomaterials, while kaolin is plate-like. In theory, tubular halloysite interacts more effectively with exudate components than plate-like kaolin, resulting in surprisingly effective results when using only very small amounts of halloysite additives. Halloysite clays are nanotubular, with most of the reactive hydroxyl groups located inside the nanotubes. It is hypothesized that the interior of the halloysite nanotube material can trap lower molecular weight (MW) components in the formulated product. The exterior of the halloysite tubular nanoparticles has a lower concentration of reactive groups, such that the amount of undesired crosslinking of the matrix polymer should be lower.

[0027] Without limiting the scope of the invention or the claims, it is believed that the ability of halloysite to reduce the migration of organic substances stems from the interaction of those substances with the aluminol groups inside the nanotubes. Accordingly, the present invention should be broadly applicable to various formulated products for controlling the thermal and electromagnetic properties of materials, where the migration of organic substances within the composite to locations outside the composite is not desired.

[0028] Accordingly, the present disclosure relates to reducing the migration of materials (e.g., oil exudates, etc.) from thermal management and / or electromagnetic interference (EMI) mitigation materials (e.g., thermal interface materials (TIMs), EMI absorbers, thermally conductive EMI absorbers, electrically conductive elastomers (ECEs), electrically conductive composites, combinations thereof, etc.) and other polymer-inorganic composites for other purposes. In an exemplary embodiment, the composite includes a sufficient amount of halloysite and / or other hollow nanotubular inorganic structures or tubular inorganic nanomaterials, such as imogolite, Saudi halloysite-like nanotubes, etc., in an amount sufficient to reduce the migration of materials from the composite. The composite can include thermal management and / or electromagnetic interference (EMI) mitigation materials, such as thermal interface materials (TIMs), EMI absorbers, thermally conductive EMI absorbers, electrically conductive elastomers (ECEs), electrically conductive composites, or combinations thereof.

[0029] Referring to the drawings, Figure 1 first and second thermal management and / or electromagnetic interference (EMI) mitigation materials 100, 112 are shown, which include halloysite and / or hollow nanotubular inorganic structures or tubular inorganic nanomaterials (broadly speaking, oil-absorbing additives) in an amount sufficient to reduce the migration of materials (e.g., silicone exudates, etc.) from the first and second thermal management and / or electromagnetic interference (EMI) mitigation materials 100, 112. As shown, the first thermal management and / or electromagnetic interference (EMI) mitigation material 100 is located between the board-level shield 104 and the integrated circuit or chip 108. The second thermal management and / or electromagnetic interference (EMI) mitigation material 112 is positioned between the heat sink 116 and the board-level shield 104.

[0030] The first thermal management and / or electromagnetic interference (EMI) mitigation material 100 may include a thermally conductive EMI absorber that is operable as a thermal interface material for establishing a thermally conductive heat path between the integrated circuit 108 and the board-level shield 104 and as an EMI absorber for suppressing the radiative electromagnetic fields coupled between the integrated circuit 108 and the heat sink 116. Thus, the first thermal management and / or electromagnetic interference (EMI) mitigation material 100 can thus provide the combined performance of a thermal interface material and an EMI absorber in a space-saving dual-purpose single-product solution.

[0031] As described above, the first thermal management and / or electromagnetic interference (EMI) mitigation material 100 includes halloysite and / or other hollow nanotubular inorganic structures or tubular inorganic nanomaterials, such as imogolite, Saudi halloysite-like nanotubes, etc., in an amount sufficient to reduce the migration of materials from the first thermal management and / or electromagnetic interference (EMI) mitigation material 100 (e.g., silicone exudates, etc.). The first thermal management and / or electromagnetic interference (EMI) mitigation material 100 also includes functional fillers (e.g., at least about 25 wt%, at least about 80 wt%, at least about 90 wt%, etc.) in a matrix or base material (e.g., silicone-based polymer resin, non-silicone-based polymer resin, etc.) for increasing thermal conductivity and / or for EMI absorption. Exemplary functional fillers include carbon black, boron nitride, nickel cobalt, carbonyl iron, iron silicide, 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, etc.), thermally conductive materials including metal complexes with a melting point close to or below room temperature (e.g., gallium and gallium alloys, etc.), combinations thereof, etc.

[0032] In an exemplary embodiment, the first thermal management and / or electromagnetic interference (EMI) mitigation material 100 comprises less than about 10 wt% of a matrix or base material, halloysite nanotubes of about 1 wt% or less, and at least about 90 wt% of a functional filler. In other exemplary embodiments, the first thermal management and / or electromagnetic interference (EMI) mitigation material 100 may comprise different weight percentages of halloysite nanotubes or other hollow nanotubular inorganic structures or tubular inorganic nanomaterials, such as less than about 10 wt%, about 5 to 10 wt%, about 0.1 to 2 wt%, etc. The first thermal management and / or electromagnetic interference (EMI) mitigation material 100 may also comprise different weight percentages of the matrix or base material (e.g., about 7 wt%, about 8 wt%, greater than 10 wt%, etc.) and / or different weight percentages of the functional filler (e.g., greater than about 25 wt%, at least about 80 wt% but less than 90 wt%, greater than 90 wt%, etc.).

[0033] In Figure 1 the example shown, the first thermal management and / or electromagnetic interference (EMI) mitigation material 100 comprises a thermally conductive EMI absorbing pad having a rectangular shape. Alternatively, the first thermal management and / or electromagnetic interference (EMI) mitigation material 100 may comprise a thermally conductive EMI absorbing pad having a different shape (such as different polygonal shapes (e.g., pentagon, triangle, etc.)).

[0034] The second thermal management and / or electromagnetic interference (EMI) mitigation material 112 may comprise a thermal interface material (TIM) operable to establish a thermally conductive path between the heat sink 116 and the board-level shield 104. As described above, the second thermal management and / or electromagnetic interference (EMI) mitigation material 112 comprises halloysite and / or other hollow nanotubular inorganic structures or tubular inorganic nanomaterials, such as imogolite, Saudi halloysite-like nanotubes, etc., in an amount sufficient to reduce the migration of materials (e.g., silicone exudates, etc.) from the second thermal management and / or electromagnetic interference (EMI) mitigation material 112. The second thermal management and / or electromagnetic interference (EMI) mitigation material 112 also comprises a thermally conductive filler (e.g., greater than about 25 wt%, at least about 80 wt%, at least about 90 wt%, etc.) in a matrix or base material (e.g., silicone-based polymer resin, non-silicone-based polymer resin, etc.). The thermally conductive filler may comprise one or more of alumina, aluminum, zinc oxide, boron nitride, silicon nitride, aluminum nitride, iron, metal oxides, graphite, silver, copper, ceramics, thermally conductive materials including metal complexes having a melting point close to or below room temperature (e.g., gallium and gallium alloys, etc.), combinations thereof.

[0035] By way of example only, the second thermal management and / or electromagnetic interference (EMI) mitigation material 112 can include less than about 10 wt% of a matrix or base material, less than about 1 wt% of halloysite additive, and at least about 90 wt% of a thermally conductive filler. In other exemplary embodiments, the second thermal management and / or electromagnetic interference (EMI) mitigation material 112 can include different weight percentages of halloysite nanotubes or other hollow nanotubular inorganic structures or tubular inorganic nanomaterials, such as less than about 10 wt%, from about 5 wt% to 10 wt%, from about 0.1 wt% to 2 wt%, etc. The second thermal management and / or electromagnetic interference (EMI) mitigation material 112 can also include different weight percentages of a matrix or base material (e.g., about 7 wt%, about 8 wt%, greater than 10 wt%, etc.) and / or different weight percentages of functional fillers (e.g., greater than about 25 wt%, at least about 80 wt% but less than 90 wt%, greater than 90 wt%, etc.).

[0036] In Figure 1 the example shown, the second thermal management and / or electromagnetic interference (EMI) mitigation material 112 includes a thermally conductive pad having a rectangular shape. Alternatively, the second thermal management and / or electromagnetic interference (EMI) mitigation material 112 can include thermally conductive pads having different shapes, such as different polygonal shapes (e.g., pentagon, triangle, etc.). In alternative embodiments, the second thermal management and / or electromagnetic interference (EMI) mitigation material 112 can include dispensable materials, thermal grease, bulk putty, phase change TIMs, etc.

[0037] Methods for reducing the migration of materials from composites (e.g., silicone exudates, etc.) are disclosed herein, the composites such as thermal management and / or electromagnetic interference (EMI) mitigation materials (e.g., thermal interface materials (TIMs), EMI absorbers, thermally conductive EMI absorbers, conductive elastomers (ECEs), conductive composites, combinations thereof, etc.) and other polymer-inorganic composites for other purposes.

[0038] In an exemplary embodiment, a method includes adding halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials to a composite in an amount sufficient to reduce the migration of materials from the composite. In such an exemplary embodiment, the hollow inorganic nanotubular structures and / or tubular inorganic nanomaterials added to the composite can include halloysite and / or other hollow inorganic nanotubular structures / tubular inorganic nanomaterials, such as imogolite, Saudi halloysite-like nanotubes, etc.

[0039] In an exemplary embodiment, the composite is a polymer-inorganic composite based on polydimethylsiloxane (PDMS). And the method includes adding halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials to the polymer-inorganic composite based on polydimethylsiloxane (PDMS).

[0040] In an exemplary embodiment, the composite is a polymer-inorganic composite substantially free of siloxane polymers. And the method includes adding halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials to the polymer-inorganic composite substantially free of siloxane polymers.

[0041] In an exemplary embodiment, the method further includes adding one or more of the following to the composite: a thermal conductive filler, an electrically conductive filler, an electromagnetic wave absorbing filler, a dielectric absorbing filler, and a filler having two or more properties of thermal conductivity, electrical conductivity, dielectric absorption, and electromagnetic wave absorption. For example, the method may include adding one or more of the following to the composite: carbon black, boron nitride, nickel cobalt, carbonyl iron, iron silicide, iron particles, iron chromium compounds, silver, an alloy containing 85% iron, 9.5% silicon, and 5.5% aluminum, an alloy containing approximately 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, etc.), a thermal conductive material including a metal composite having a melting point close to or below room temperature (e.g., gallium and gallium alloys, etc.), combinations thereof, etc.

[0042] In an exemplary embodiment, the method includes adding halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in an amount sufficient for the following purposes: absorbing and / or binding the uncrosslinked polymer of the composite, which otherwise may migrate from the composite; and / or absorbing mildly crosslinked and / or low molecular weight crosslinked polymers and other fluid materials and additives, which otherwise may migrate from the composite.

[0043] In an exemplary embodiment, the method includes adding halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials to the composite in an amount sufficient to reduce the exudation of silicone oil from the composite, so that the composite can be used substantially or completely without silicone migrating beyond the scope of the composite, and is easily deflected under a low level of applied force.

[0044] In an exemplary embodiment, the method includes adding halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials to a composite such that the composite includes up to about 10 wt% of halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials. For example, the composite may include less than about 10 wt% of halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials. Alternatively, for example, the composite may include about 5 to 10 wt% of halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials. As another example, the composite may include about 0.1 to 2 wt% of halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials. As yet another example, the composite may include about 1 wt% of halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials.

[0045] In an exemplary embodiment, the composite is a thermal management and / or electromagnetic interference (EMI) mitigation material that can be used to manage the thermal and / or electromagnetic properties of a device or system.

[0046] In an exemplary embodiment, the composite is a thermal interface material, EMI absorber, thermal conductive absorber, conductive elastomer, conductive composite, or a combination of two or more thereof. For example, the composite may include a thermal interface material that is a thermal pad, thermal gap filler, dispensable material, thermal paste, bulk putty, or phase change TIM.

[0047] In an exemplary embodiment, the method includes using the composite to manage the thermal and / or electromagnetic properties of a device or system.

[0048] In an exemplary embodiment, the method includes dispensing the composite onto the surface of a device for managing the thermal and / or electromagnetic properties of the device or a system including the device.

[0049] In an exemplary embodiment, the method includes removing a release liner from the composite and positioning the composite onto the surface of a device for managing the thermal and / or electromagnetic properties of the device or a system including the device.

[0050] In an exemplary embodiment, the composite contains an amount of halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials sufficient to reduce the migration of materials from the composite. In such an exemplary embodiment, the hollow nanotubular inorganic structures and / or tubular inorganic nanomaterials, the hollow inorganic substances, may include halloysite and / or other hollow inorganic nanotubular structures / tubular inorganic nanomaterials, such as imogolite, Saudi halloysite-like nanotubes, etc.

[0051] In an exemplary embodiment, the composite is a polydimethylsiloxane (PDMS)-based polymer-inorganic composite.

[0052] In an exemplary embodiment, the composite is a polymer-inorganic composite that is substantially free of silicone polymers.

[0053] In an exemplary embodiment, the composite further comprises one or more of the following: a thermal conductive filler, a conductive filler, an electromagnetic wave absorbing filler, a dielectric absorbing filler, and a filler having two or more properties of thermal conductivity, conductivity, dielectric absorption, and electromagnetic wave absorption. For example, the composite may include one or more of some of the following: carbon black, boron nitride, nickel cobalt, iron carbonyl, iron silicide, 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, ferrite, magnetic alloy, magnetic powder, magnetic sheet, magnetic particles, nickel-based alloy and powder, chromium alloy, oxide, copper, zinc oxide, aluminum oxide, graphite, ceramic, silicon carbide, manganese zinc, glass fiber, carbon nanotubes (e.g., single-walled carbon nanotubes, multi-walled carbon nanotubes, etc.), a thermal conductive material including a metal composite having a melting point close to or below room temperature (e.g., gallium and gallium alloys, etc.), combinations thereof, and the like.

[0054] In an exemplary embodiment, the amount of halloysite, hollow nanotubular inorganic structure, and / or tubular inorganic nanomaterial is sufficient to: absorb and / or bind the uncrosslinked polymer of the composite, which otherwise may migrate from the composite; and / or absorb the lightly crosslinked and / or low molecular weight crosslinked polymer and other fluid materials and additives, which otherwise may migrate from the composite.

[0055] In an exemplary embodiment, the amount of halloysite, hollow nanotubular inorganic structure, and / or tubular inorganic nanomaterial is sufficient to reduce the exudation of silicone oil from the composite, so that the composite can be used substantially or completely without silicone migrating beyond the scope of the composite, and is easily deflected under a low level of applied force.

[0056] In an exemplary embodiment, the composite comprises up to about 10 wt% of halloysite, hollow nanotubular inorganic structure, and / or tubular inorganic nanomaterial. For example, the composite may include less than about 10 wt% of halloysite, hollow nanotubular inorganic structure, and / or tubular inorganic nanomaterial. Alternatively, for example, the composite may include about 5 to 10 wt% of halloysite, hollow nanotubular inorganic structure, and / or tubular inorganic nanomaterial. As another example, the composite may include about 0.1 to 2 wt% of halloysite, hollow nanotubular inorganic structure, and / or tubular inorganic nanomaterial. As yet another example, the composite may include about 1 wt% of halloysite, hollow nanotubular inorganic structure, and / or tubular inorganic nanomaterial.

[0057] As another example, the composite may include a matrix or base material in different weight percentages, such as about 7 wt%, about 8 wt%, about 10 wt%, greater than 10 wt%, etc. By way of further example, the composite may contain fillers in different weight percentages, such as greater than about 25 wt%, at least about 80 wt% but less than 90 wt%, greater than 90 wt%, etc.

[0058] In an exemplary embodiment, the composite is electrically conductive or electrically insulating, thermally conductive or thermally insulating, EMI-absorbing, or a combination of any or all of the foregoing properties.

[0059] In an exemplary embodiment, the composite is configured to be useful for managing the thermal and / or electromagnetic properties of a device or system.

[0060] In an exemplary embodiment, the composite is a thermal management and / or electromagnetic interference (EMI) mitigation material.

[0061] In an exemplary embodiment, the composite is a thermal interface material, an EMI absorber, a thermally conductive absorber, a conductive elastomer, a conductive composite, or a combination of two or more thereof.

[0062] In an exemplary embodiment, a device or system includes a composite as disclosed herein for managing the thermal and / or electromagnetic properties of the device or system.

[0063] In an exemplary embodiment, the composite is EMI-absorbing and / or electrically conductive such that the composite can be used to mitigate and / or manage EMI within an electronic device.

[0064] In an exemplary embodiment, an electronic device includes a heat source and a composite as disclosed herein. The composite is positioned relative to the heat source to establish at least a portion of a thermally conductive heat path through the composite from the heat source. Halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in the composite reduce the migration of materials (such as silicone oil exudates, etc.) from the composite onto the heat source. The composite can also be configured to be EMI-absorbing and / or electrically conductive such that the composite is also operable to mitigate and / or manage EMI within the electronic device.

[0065] In an exemplary embodiment, an electronic device includes a heat source, a heat removal / dissipation structure, and a composite as disclosed herein. The composite is positioned relative to the heat source and the heat removal / dissipation structure to establish at least a portion of a thermally conductive heat path between the heat source and the heat removal / dissipation structure. Halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in the composite reduce the migration of materials (such as silicone oil exudates, etc.) from the composite onto 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 also operable to mitigate and / or manage EMI within the electronic device.

[0066] In an exemplary embodiment, an electronic device includes a heat source, a board-level shield, and a composite as disclosed herein. The composite is positioned relative to the heat source and the board-level shield to establish at least a portion of a thermally conductive path between the heat source and the board-level shield. Halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in the composite reduce the migration of materials (e.g., silicone exudates, etc.) from the composite onto the heat source and the board-level shield. The composite can also be configured to be EMI-absorbing and / or conductive, such that the composite is also operable to mitigate and / or manage EMI within the electronic device.

[0067] In an exemplary embodiment, an electronic device includes a heat source, a board-level shield, a heat removal / dissipation structure, and first and second composites as disclosed herein. The first composite is positioned relative to the heat source and the board-level shield to establish at least a portion of a first thermally conductive path between the heat source and the board-level shield. Halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in the first composite reduce the migration of materials (e.g., silicone oil exudates, etc.) from the first composite onto the heat source and the board-level shield. The second composite is positioned relative to the board-level shield and the heat removal / dissipation structure to establish at least a portion of a second thermally conductive path between the board-level shield and the heat removal / dissipation structure. Halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in the second composite reduce the migration of materials (e.g., silicone oil exudates, etc.) from the second composite onto the board-level shield and the heat removal / dissipation structure. The first composite and / or the second composite can also be configured to be EMI-absorbing and / or conductive, such that the first composite and / or the second composite are also operable to mitigate and / or manage EMI within the electronic device.

[0068] In an exemplary embodiment, an electronic device includes an integrated circuit, a board-level shield, a heat sink, and first and second composites as disclosed herein. The first composite is positioned relative to the integrated circuit and the board-level shield to establish at least a portion of a first thermally conductive path between the integrated circuit and the board-level shield. Halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in the first composite reduce the migration of materials (e.g., silicone oil exudates, etc.) from the first composite onto the integrated circuit and the board-level shield. The second composite is positioned relative to the board-level shield and the heat sink to establish at least a portion of a second thermally conductive path between the board-level shield and the heat sink. Halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in the second composite reduce the migration of materials (e.g., silicone oil exudates, etc.) from the second composite onto the board-level shield and the heat sink. The first composite and / or the second composite can also be configured to be EMI-absorbing and / or conductive, such that the first composite and / or the second composite are also operable to mitigate and / or manage EMI within the electronic device.

[0069] In addition to halloysite and / or other tubular nanomaterials / hollow nanotubular additives (such as imogolite, Saudi halloysite-like nanotubes, etc.) used to reduce material migration (e.g., silicone oil exudates, etc.), one or more other suitable fillers and / or additives can be added to the bulk material of other polymer-inorganic composites for thermal management and / or EMI mitigation materials or for other purposes. For example, one or more of the following can also be added: functional nanoparticles, conductive fillers, thermally conductive fillers, EMI or microwave absorbing fillers, magnetic fillers, coated fillers, catalysts for controlling curing, coupling agents for increasing filler loading, pigments or dyes for adding color, plasticizers, processing aids, flame retardants, extenders, tackifiers, antioxidants, ultraviolet (UV) stabilizers, heat stabilizers, combinations thereof, etc. The fillers can be added and mixed into the bulk material including the matrix or base material, thereby providing a mixture of the fillers, halloysite additives, and the matrix or base material. Exemplary fillers include carbon black, boron nitride, nickel cobalt, carbonyl iron, iron silicide, iron particles, iron-chromium compounds, silver, an alloy containing 85% iron, 9.5% silicon, and 5.5% aluminum, an alloy containing approximately 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.), thermally conductive materials including metal composites with a melting point close to or below room temperature (e.g., gallium and gallium alloys, etc.), combinations thereof, etc. In addition, exemplary embodiments can also include different grades (e.g., different sizes, different purities, different shapes, etc.) of the same (or different) fillers.

[0070] In an exemplary embodiment where the composite includes halloysite nanotubes, the halloysite nanotubes can include an aluminosilicate clay hollow nanotube structure having a chemical composition of Al2Si2O5(OH)4·nH2O. The aluminosilicate clay hollow nanotubular structure can have a wall thickness of aluminosilicate sheets of about 10 to 15 atoms, an outer diameter of about 50 to 70 nanometers (nm), an inner diameter of about 10 to 15 nm, and a length of 0.5 to 10 micrometers (μm).

[0071] In an exemplary embodiment, the composite complies with ROHS Directive 2011 / 65 / EU and (EU) 2015 / 863 and / or complies with REACH because it contains less than 0.1% by weight of substances on the REACH / SVHC candidate list (June 25, 2020). In an exemplary embodiment, the composite contains no more than 0.01% by weight of cadmium at the regulatory threshold, no more than 0.1% by weight of lead at the regulatory threshold, no more than 0.1% by weight of mercury at the regulatory threshold, no more than 0.1% by weight of hexavalent chromium at the regulatory threshold, no more than 0.1% by weight of the flame retardants PBB and PBDE, including pentabromodiphenyl ether (CAS-No. 32534-81-9), octabromodiphenyl ether (CAS-No. 32536-52-0), and decabromodiphenyl ether (CAS-No. 1163-19-5), no more than 0.1% by weight of bis(2-ethylhexyl) phthalate (DEHP) (CAS-No. 117-81-7) at the regulatory threshold, no more than 0.1% by weight of butyl benzyl phthalate (BBP) (CAS-No. 85-68-7) at the regulatory threshold, no more than 0.1% by weight of dibutyl phthalate (DBP) (CAS-No. 84-74-2) at the regulatory threshold, and no more than 0.1% by weight of diisobutyl phthalate (DIBP) (CAS-No. 84-69-5) at the regulatory threshold.

[0072] Exemplary embodiments of the thermal management and / or EMI mitigation materials disclosed herein can be used in a wide range of industries (e.g., automotive, consumer, industrial, telecommunications / data communication, aerospace / defense, etc.) and a wide range of applications (e.g., automotive electronics, automotive advanced driver assistance systems (ADAS), automotive powertrain / electronic control units (ECU), automotive infotainment, routers, wireless infrastructure, drones / satellites, gaming systems, smart home devices, laptop / tablet / portable devices, etc.).

[0073] In an exemplary embodiment, a composite including halloysite and / or other hollow nanotubular inorganic structures or tubular inorganic nanomaterials (e.g., imogolite, Saudi halloysite-like nanotubes, etc.) is provided as a thermal gap filler sheet having a thickness in the range of about 0.1 mm to about 10 mm. The thermal gap filler sheet may have a thermal conductivity of at least about 4 watts per meter per Kelvin (W / mK). The thermal gap filler sheet may be dielectric rather than conductive. The thermal gap filler sheet may have a hardness of less than about 44 Shore 00 at 3 seconds. The values provided in this paragraph are merely examples, as other embodiments may be configured differently, such as having different thicknesses, a hardness greater than about 44 Shore 00 at 3 seconds, and / or a thermal conductivity higher or lower than 4 W / mK, etc. In other exemplary embodiments, the composite may have a hardness within a defined range (e.g., + / - 10, etc.) of about 80 Shore 00 (e.g., about 80 Shore 00 at 3 seconds, about 70 Shore 00 at 3 seconds, about 60 Shore 00 at 3 seconds, etc.). In other exemplary embodiments, the composite (e.g., EMI absorber, etc.) may have a hardness within the Shore A range.

[0074] In an exemplary embodiment, a composite including halloysite and / or other hollow nanotubular inorganic structures or tubular inorganic nanomaterials (e.g., imogolite, Saudi halloysite-like nanotubes, etc.) is a thermal interface material (TIM), such as a thermal pad, a thermal gap filler, a dispensable material, a thermal paste, a bulk putty, a phase change TIM, etc. In an exemplary embodiment, a composite including halloysite nanotubes or other hollow nanotubular inorganic structures or tubular inorganic nanomaterials is a thermal management and / or EMI mitigation material having a relatively high thermal conductivity (e.g., 1 W / mK (watts per meter per Kelvin), 1.1 W / mK, 1.2 W / mK, 2.8 W / mK, 3 W / mK, 3.1 W / mK, 3.8 W / mK, 4 W / mK, 4.7 W / mK, 5 W / mK, 5.4 W / mK, 6 W / mK, 8 W / mK, etc.), depending on the loading percentages used to prepare the thermal management and / or EMI mitigation material and the thermal filler (if any). These thermal conductivities are merely examples, as other embodiments may include thermal management and / or EMI mitigation materials having a thermal conductivity higher than 8 W / mK, less than 1 W / mK (e.g., at least about 0.3 W / mK, etc.), or values within the range of 1 W / mK to 8 W / mK.

[0075] In an exemplary embodiment, a thermal management and / or EMI mitigation material (e.g., a thermal interface material, a thermally conductive EMI absorber, etc.) including halloysite and / or other hollow nanotubular inorganic structures or tubular inorganic nanomaterials can be used to define or provide a part of a thermally conductive heat path from a heat source to a heat removal / dissipation structure or component. For example, the thermal management and / or EMI mitigation material can be used to help conduct thermal energy (e.g., heat, etc.) away from a heat source of an electronic device. The thermal management and / or EMI mitigation material can generally be positioned between the heat source and the heat removal / dissipation structure or component (e.g., in direct physical contact, thermal contact, etc. therewith) to establish a thermal joint, interface, path, or thermally conductive heat path along which heat can be transferred (e.g., conducted) from the heat source to the heat removal / dissipation structure or component. During operation, the thermal management and / or EMI mitigation material can be used to allow heat to be transferred (e.g., conduct heat, etc.) from the heat source along the thermally conductive path to the heat removal / dissipation structure or component. In an exemplary embodiment, the thermal management and / or EMI mitigation material can also be operable to mitigate EMI incident on the thermal management and / or EMI mitigation material (e.g., absorb EMI, etc.).

[0076] The exemplary embodiments disclosed herein can be used with a variety of heat sources, electronic devices, and / or heat removal / dissipation structures or components (e.g., heat sinks, heat exchangers, heat pipes, vapor chambers, device enclosures, housings, or chassis, etc.). 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.), memories 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 having a higher temperature than the thermal management and / or EMI mitigation material or otherwise providing or transferring heat to the thermal management and / or EMI mitigation material, regardless of whether the heat is generated by the heat source or merely passed through or via the heat source. Thus, 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.

[0077] Exemplary embodiments are provided so that this disclosure will be thorough and will fully convey the scope to those 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 the embodiments of this disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that the exemplary embodiments may be embodied in many different forms, and that no element of the content should be construed as limiting the scope of this disclosure. In some exemplary embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. Additionally, the advantages and improvements that can be achieved with one or more of the exemplary embodiments of the present invention are provided for illustrative purposes only and do not limit the scope of this disclosure (since the exemplary embodiments disclosed herein may provide all of the above advantages and improvements or none of them and still fall within the scope of this disclosure).

[0078] The specific dimensions, specific materials, and / or specific shapes disclosed herein are exemplary in nature and do not limit the scope of this disclosure. The disclosure of specific values and specific value ranges for a given parameter herein is not an exhaustive disclosure of other values and value ranges that may be used in one or more of the examples disclosed herein. Moreover, it is contemplated that any two specific values for a given parameter described herein may define the endpoints of a value range that may be suitable for the given parameter (i.e., the disclosure of a first value and a second value for a given parameter may be interpreted as disclosing that any value between the first and second values may also be used for the given parameter). For example, if parameter X is exemplified herein as having value A and is also exemplified as having value Z, it is contemplated that parameter X may have a value range from approximately A to approximately Z. Similarly, the disclosure of two or more value ranges for a parameter (regardless of whether such ranges are nested, overlapping, or distinct) is contemplated to include all possible combinations of value ranges that can be clamped by the endpoints of the disclosed ranges. For example, if parameter X is exemplified 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.

[0079] The terms used herein are for the purpose of describing particular exemplary embodiments only and are not intended to be limiting. As used herein, the singular forms "a" and "an" may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprising" and "having" are inclusive, so specifying the presence of the recited features, integers, steps, operations, elements, and / or components, but not precluding 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 discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

[0080] When an element or layer is referred to as being "on", "engaged to", "connected to" or "coupled to" another element or layer, it can be directly on, engaged, connected or coupled directly to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on", "directly engaged to", "directly connected to" or "directly coupled to" another element or layer, intervening elements or layers may not be present. Other words used to describe the relationship between elements should be interpreted in a like 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.

[0081] The term "about", when applied to a value, indicates that the calculation or measurement allows for some slight imprecision in the value (being close to the exact value; approximate or reasonably close to the value; nearly). If for some reason the imprecision provided by "about" is not otherwise understood in the art in this ordinary sense, then "about" as used herein indicates at least a variation that may be caused by ordinary measurement methods or the use of such parameters. For example, the terms "substantially", "about" and "approximately" may be used herein to mean within manufacturing tolerances. Whether or not modified by the term "about", the claims include equivalents of the quantities.

[0082] Although the terms first, second, third, etc. may 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 may only be used to distinguish one element, component, region, layer or section from another. Terms such as "first", "second" and other numerical terms when used herein do not imply an order, unless the context clearly indicates otherwise. Thus, a first element, component, region, layer or section discussed below may be referred to as a second element, component, region, layer or section without departing from the teachings of the exemplary embodiments.

[0083] Spatially relative terms, such as "inner", "outer", "beneath", "below", "lower", "above", "upper", etc., may be used herein for convenience of description to describe the relationship of one element or feature to another element or feature as illustrated in the figures. Spatially relative terms are 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, an element described as "below" or "beneath" another element or feature will be oriented "above" the other element or feature. Thus, the exemplary term "below" can encompass both an above and below orientation. The device may be otherwise oriented (rotated 90 degrees or at other orientations), so the spatially relative descriptors used herein are to be interpreted accordingly.

[0084] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. The individual elements, contemplated uses, or features of a particular embodiment are generally not limited to that particular embodiment, but rather are interchangeable, and can be used in the selected embodiment (even if not specifically shown or described for that embodiment), where appropriate. The same also can be changed in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

1. A method comprising adding halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials to a composite in an amount sufficient to reduce migration of materials from the composite.

2. The method according to claim 1, wherein The method comprises adding the halloysite to the composite in an amount sufficient to reduce migration of materials from the composite.

3. The method according to claim 1, wherein The method comprises adding the hollow nanotubular inorganic structures to the composite in an amount sufficient to reduce migration of materials from the composite.

4. The method according to claim 1, wherein, The method comprises adding the tubular inorganic nanomaterials to the composite in an amount sufficient to reduce migration of materials from the composite.

5. The method according to claim 1, wherein: the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials comprise hollow nanotubular halloysite structures; and the method comprises adding the hollow nanotubular halloysite structures to the composite in an amount sufficient to reduce migration of materials from the composite.

6. The method according to claim 1, wherein: the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials comprise tubular halloysite nanomaterials; and the method comprises adding the tubular halloysite nanomaterials to the composite in an amount sufficient to reduce migration of materials from the composite.

7. The method according to any one of claims 1 to 6, wherein, The amount of the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials is sufficient to reduce the exudation of silicone oil from the composite such that the composite can be used with substantially or completely no silicone migration beyond the composite and can be easily deflected under a low level of applied force.

8. The method according to any one of claims 1 to 6, wherein The composite is a polymer-inorganic composite based on polydimethylsiloxane (PDMS).

9. The method according to any one of claims 1 to 6, wherein The composite is a polymer-inorganic composite substantially free of silicone polymers.

10. The method according to any one of claims 1 to 6, wherein The method further comprises adding one or more of the following to the composite: thermal conductive fillers; conductive fillers; electromagnetic wave absorbing fillers; dielectric absorbing fillers; and fillers having two or more properties of thermal conductivity, conductivity, dielectric absorption, and electromagnetic wave absorption.

11. The method according to any one of claims 1 to 6, wherein, The amount of the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials is sufficient to absorb and / or bind uncrosslinked polymers in the composite that might otherwise migrate from the composite.

12. The method according to any one of claims 1 to 6, wherein, The amount of the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials is sufficient to absorb mildly crosslinked and / or low molecular weight crosslinked polymers as well as other fluid materials and additives that might otherwise migrate from the composite.

13. The method according to any one of claims 1 to 6, wherein, The composite comprises up to about 10 wt% of the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials.

14. The method according to any one of claims 1 to 6, wherein, The composite is a thermal interface material, EMI absorber, thermal absorber, conductive elastomer, conductive composite, or a combination of two or more thereof.

15. The method according to any one of claims 1 to 6, wherein The composite is a thermal management and / or electromagnetic interference (EMI) mitigation material capable of being used to manage the thermal and / or electromagnetic properties of a device or system.

16. The method according to any one of claims 1 to 6, wherein, The method comprises using the composite to manage the thermal and / or electromagnetic properties of a device or system.

17. The method according to any one of claims 1 to 6, wherein The method includes dispensing the composite onto the surface of a device for managing the thermal and / or electromagnetic properties of the device and / or for managing the thermal and / or electromagnetic properties of a system including the device.

18. The method according to any one of claims 1 to 6, wherein The method includes: removing a release liner from the composite; and positioning the composite onto the surface of a device for managing the thermal and / or electromagnetic properties of the device and / or for managing the thermal and / or electromagnetic properties of a system including the device.

19. A composite comprising halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials in an amount sufficient to reduce the migration of materials from the composite.

20. The composite according to claim 19, wherein: the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials comprise halloysite; and the composite comprises halloysite in an amount sufficient to reduce the migration of materials from the composite.

21. The composite as claimed in claim 19, wherein: the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials include hollow nanotubular inorganic structures; and the composite comprises hollow nanotubular inorganic structures in an amount sufficient to reduce the migration of materials from the composite.

22. The composite according to claim 19, wherein: the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials include tubular inorganic nanomaterials; and the composite comprises tubular inorganic nanomaterials in an amount sufficient to reduce the migration of materials from the composite.

23. The composite according to claim 19, wherein: the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials include hollow nanotubular halloysite structures; and the composite comprises hollow nanotubular halloysite structures in an amount sufficient to reduce the migration of materials from the composite.

24. The composite according to claim 19, wherein: the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials include tubular halloysite nanomaterials; and the composite comprises tubular halloysite nanomaterials in an amount sufficient to reduce the migration of materials from the composite.

25. The composite according to any one of claims 19 to 24, wherein, The amount of the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials is sufficient to reduce the exudation of silicone oil from the composite, such that the composite can be used with substantially or completely no silicone migration beyond the composite and is easily deflectable under a low level of applied force.

26. The composite according to any one of claims 19 to 24, wherein, The composite is a polymer-inorganic composite based on polydimethylsiloxane (PDMS).

27. The composite according to any one of claims 19 to 24, wherein The composite is a polymer-inorganic composite substantially free of silicone polymers.

28. The composite according to any one of claims 19 to 24, wherein, The composite further comprises one or more of the following: thermal conductive fillers; conductive fillers; electromagnetic wave absorbing fillers; dielectric absorbing fillers; and fillers having two or more properties of thermal conductivity, conductivity, dielectric absorption, and electromagnetic wave absorption.

29. The composite according to any one of claims 19 to 24, wherein, The amount of the halloysite, hollow nanotubular inorganic structures, and / or tubular inorganic nanomaterials is sufficient to absorb and / or bind uncrosslinked polymers in the composite, which otherwise may migrate from the composite.

30. The composite according to any one of claims 19 to 24, wherein, The amount of the halloysite, hollow nanotubular inorganic structure, and / or tubular inorganic nanomaterial is sufficient to absorb mildly crosslinked and / or low molecular weight crosslinked polymers and other fluid materials and additives that might otherwise migrate from the composite.

31. The composite according to any one of claims 19 to 24, wherein, The composite comprises up to about 10 wt% of the halloysite, hollow nanotubular inorganic structure, and / or tubular inorganic nanomaterial.

32. The composite according to any one of claims 19 to 24, wherein, The composite is configured to be useful for managing the thermal and / or electromagnetic properties of a device or system.

33. The composite according to any one of claims 19 to 24, wherein The composite is a thermal management and / or electromagnetic interference (EMI) mitigation material.

34. The composite according to any one of claims 19 to 24, wherein, The composite is a thermal interface material, EMI absorber, thermal conductivity absorber, conductive elastomer, conductive composite, or a combination of two or more thereof.

35. A device or system comprising the composite according to any one of claims 19 to 24, the composite being for managing the thermal and / or electromagnetic properties of the device or system.

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