Phosphonic acids for enhanced performance of thermal interface materials

Abstract

To provide a composite material used for managing thermal characteristics of a device or a system and having improved performance.SOLUTION: The present disclosure relates to the use of phosphonic acids to enhance the performance of thermal interface materials (broadly, composite materials), for example, by improving rheological properties, improving aging characteristics, improving shelf life, improving tack / adhesion, and / or reducing the diffusion of materials that migrate therefrom, if any, such as reducing oil bleed diffusion. The present disclosure also relates to methods of using phosphonic acids to improve the performance of composite materials useful for thermal and / or electromagnetic interference (EMI) management. The composite material can include a thermal management and / or electromagnetic interference (EMI) mitigation material, such as a thermal interface material (TIM), an EMI absorber material, a thermally conductive EMI absorber material, an electrically conductive material, combinations thereof, and the like.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to the use of phosphonic acids to improve the performance of thermal interface materials (broadly, composite materials), for example, by improving rheological properties, improving aging properties, improving shelf life, improving tack / adhesion, and / or reducing the diffusion of migrating materials, if any, therefrom (e.g., reducing oil-bleed diffusion, etc.). [Background technology]

[0002] This section provides background information related to the present disclosure that is not necessarily prior art. Electrical components, such as semiconductors, integrated circuit packages, transistors, and the like, typically have a pre-designed temperature at which they optimally operate. Ideally, the pre-designed temperature is close to the temperature of the surrounding air. However, operation of the 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 temperature. Such excessive temperatures can adversely affect the operating characteristics of the electrical components and the operation of associated devices.

[0003] To avoid or at least mitigate adverse operating characteristics due to heat generation, heat must be removed, for example, by conduction from an operating electrical component 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 an operating electrical component to a heat sink by direct surface contact between the electrical component and the heat sink and / or by contact between the electrical component and the heat sink surface through an intermediate medium or thermal interface material (TIM). A thermal interface material can be used to fill gaps between heat transfer surfaces to increase heat transfer efficiency compared to filling the gap with air, which has a relatively low thermal conductivity.

[0004] Additionally, a common problem in the operation of electronic devices is the generation of electromagnetic radiation within the equipment's electronic circuits. Such radiation can cause electromagnetic interference (EMI) or radio frequency interference (RFI), which can disrupt the operation of other electronic devices within a certain proximity. Without proper shielding, EMI / RFI interference can cause degradation or complete loss of important signals, thereby rendering electronic equipment inefficient or inoperable.

[0005] The term "EMI," as used herein, should generally be considered to include and refer to EMI and RFI emissions, and the term "electromagnetic" should generally be considered to include and refer to electromagnetic and radio frequencies from external and internal sources. Accordingly, the term shielding (as used herein) broadly includes and refers to reducing (or limiting) EMI and / or RFI so that it does not interfere, such as by attenuating, absorbing, reflecting, blocking, and / or redirecting energy, or some combination thereof, for example, for government compliance and / or the internal functioning of an electronic system. DETAILED DESCRIPTION OF THE INVENTION

[0006] Detailed Description Example embodiments will now be described more fully with reference to the accompanying drawings. As recognized herein, thermal interface materials (TIMs) are subject to significant performance requirements that continue to increase as devices use more power and become more integrated into field applications such as sensitive electronics or automobiles. Having recognized the above, exemplary embodiments have been developed and / or are disclosed herein that include the use of phosphonic acids to improve the performance of TIMs (broadly, composites) that contribute to properties such as rheology, aging, shelf life, bleed, and / or adhesion.

[0007] In exemplary embodiments disclosed herein, phosphonic acids are used to improve the performance of thermal interface materials (TIMs) or other composite materials useful for managing heat and / or electromagnetic interference (EMI). In some exemplary embodiments disclosed herein, the phosphonic acid is an additive added directly to the formulation for the TIM. In other exemplary embodiments, the TIM includes one or more fillers (e.g., thermally conductive particles, etc.) that are pretreated with, surface-modified with, and / or coated with phosphonic acid.

[0008] As an example, a TIM or other composite material useful for heat and / or electromagnetic interference (EMI) management may include one or more fillers (e.g., thermally conductive particles) having one or more thin films, coatings, or layers of phosphonic acid deposited thereon by liquid deposition. During the liquid deposition process, an organic solvent can be used to promote interaction between the phosphonic acid groups and the filler particle surface. One example of a liquid deposition process involves preparing a toluene, alcohol, ester, or hydrocarbon solution containing the phosphonic acid. The mixture is then stirred with the filler particles to be treated. The filler particles are washed with the solvent, which is then removed.

[0009] As a further example, a TIM or other composite material useful for heat and / or electromagnetic interference (EMI) management may include one or more fillers (e.g., thermally conductive particles, etc.) that have been treated by spraying or other methods suitable for bulk deposition onto a powder. During the spraying process, one or more thin films, coatings, or layers of phosphonic acid may be deposited on the filler particle surfaces. An exemplary method may include preparing a solution of phosphonic acid in a suitable solvent and placing the solution and filler particles (e.g., powder, etc.) in a high-intensity solids mixer (e.g., a double-cone mixer with an intensifier, etc.).

[0010] The TIM resin may comprise a siloxane and / or hydrocarbon polymer, such as a crosslinked siloxane resin system, a non-crosslinked siloxane resin system, a non-crosslinked hydrocarbon resin system, or a crosslinked hydrocarbon resin system. The TIM may also comprise one or more oils, stabilizers, dispersants, coupling agents, pigments, thixotropic agents, rheology modifiers, tackifiers, and / or solvents. The TIM may further comprise one or more fillers (e.g., ranging in size from 0.1 μm to 500 μm (D50)), such as alumina, zinc oxide, aluminum, carbonyl iron, silicon carbide, boron nitride, silver, aluminum nitride, barium titanate, carbon, graphite, other thermally conductive and / or EMI-absorbing fillers, or combinations thereof. In various resin and filler systems, phosphonic acids contribute to improved rheological properties, aging properties (cure upon exposure to high temperatures in air or high temperature / high humidity conditions), shelf life, bleed, and / or tack / adhesion.

[0011] Siloxane generally refers to compounds (e.g., silicones) with a molecular structure based on chains or functional groups of alternating silicon and oxygen atoms, often with organic groups bonded to the silicon atoms. Common siloxanes include silicone, PDMS (polydimethylsiloxane), silicone rubber, silicone oil, liquid silicone, and dimethicone.

[0012] Exemplary composite materials useful for thermal and / or electromagnetic interference (EMI) management are disclosed. In exemplary embodiments, the composite material includes a matrix, one or more fillers within the matrix, and a phosphonic acid. For example, the composite material may include about 0.01 weight percent to about 3 weight percent phosphonic acid based on the total weight of the composite material, where the amount of phosphonic acid is sufficient to improve the performance of the composite material. The phosphonic acid may be an additive added directly to the composite material formulation, and / or the composite material may include one or more fillers that have been pretreated, surface-modified, and / or coated with the phosphonic acid.

[0013] As an example, ToF-SIMS (time-of-flight secondary ion mass spectrometry) can be performed on intact materials to identify phosphonic acid species. In non-crosslinked systems, particles can be isolated and analyzed by ToF-SIMS, DRIFTS IR spectroscopy (diffuse reflectance Fourier transform infrared spectroscopy), or XPS (X-ray photoelectron spectroscopy). In crosslinked or non-crosslinked systems, free phosphonic acid in the matrix can be isolated by dissolution or extraction in a solvent, and the extract can be analyzed by UPLC / HPLC-MS, GC-MS, FTIR, or NMR.

[0014] In exemplary embodiments, the phosphonic acid may include octadecylphosphonic acid, tetradecylphosphonic acid, and / or dodecylphosphonic acid. The phosphonic acid may include an organic moiety directly bonded to the phosphorus atom through a carbon atom. Preferred phosphonic acids have organic ligands consisting of an aliphatic hydrocarbon moiety of about 2 to 20 carbon atoms. Suitable aliphatic organic ligands may be linear, branched, star-shaped, or cyclic, saturated or unsaturated, and optionally substituted with one or more functional groups, including silyl, siloxane, fluoroalkyl, aromatic, thiol, alcohol, carboxylic acid, amine, or amide substituents. Other suitable phosphonic acids may have organic ligands with linear, branched, star-shaped, or cyclic oligomeric or polymeric structures containing repeating units of polyacrylate, polymethacrylate, polystyrene, polysiloxane, polyester, polyamide, polybutadiene, hydrogenated polybutadiene, polypropylene, polyethylene, or other chemicals. The phosphonic acid may include one or more phosphonic acid groups.

[0015] In exemplary embodiments, the composite material includes at least about 0.05 weight percent but not more than about 0.25 weight percent phosphonic acid. Alternatively, the composite material includes at least about 0.1 weight percent but not more than about 0.3 weight percent phosphonic acid. By way of example only, the composite material may include about 0.05, 0.1, 0.25, or 0.3 weight percent phosphonic acid.

[0016] As disclosed herein, the phosphonic acid improves the performance of a composite material (compared to another composite material having substantially the same formulation but not containing the phosphonic acid) by one or more of improving the rheological properties of the composite material, improving the aging characteristics of the composite material, improving the shelf life of the composite material, improving tack / adhesion, and / or reducing the diffusion of any migrating material from the composite material.

[0017] In exemplary embodiments, the phosphonic acid improves the performance of the composite (compared to another composite having substantially the same formulation but without the phosphonic acid) by one or more of: an increased flow rate (grams / minute); an increased time to embrittlement (e.g., at 150°C or 200°C, at 85 percent relative humidity and temperatures of 40, 85, and / or 130°C, etc.) as measured by various tests (e.g., measuring thermal resistance, Shore hardness, bend radius, etc.); allowing the composite to achieve higher deflections; improved tack as measured by various methods (e.g., peak peel pressure or adhesion, etc.); a reduced minimum bondline thickness (BLT) at equivalent pressure; a reduced thermal resistance; a reduced modulus; and / or any combination of two or more of these performance improvements.

[0018] In an exemplary embodiment, the phosphonic acid improves the performance of the composite (compared to another composite having substantially the same formulation but without the phosphonic acid), such that the composite can achieve one or more of higher deflection, improved tack as measured by adhesive force, and / or reduced minimum bondline thickness (BLT) after aging at 150°C for 2 or 3 weeks.

[0019] In an exemplary embodiment, the phosphonic acid improves the performance of the composite (compared to another composite having substantially the same formulation but without the phosphonic acid) such that the composite achieves one or more of reduced thermal resistance and / or reduced minimum bondline thickness (BLT) after aging at elevated temperatures and high relative humidity. For example, the phosphonic acid improves the performance of the composite (compared to another composite having substantially the same formulation but without the phosphonic acid) such that the composite achieves one or more of reduced thermal resistance and / or reduced minimum bondline thickness (BLT) after aging for 48 hours at a temperature of 85°C and 85% relative humidity. As another example, the phosphonic acid improves the performance of the composite (compared to another composite having substantially the same formulation but without the phosphonic acid) such that the composite achieves a lower modulus after aging for one week at a temperature of 130°C and 85% relative humidity.

[0020] In an exemplary embodiment, the composite material includes a matrix comprising a siloxane and / or hydrocarbon polymer. For example, the matrix may include a crosslinked siloxane resin system, a non-crosslinked siloxane resin system, a non-crosslinked hydrocarbon resin system, or a crosslinked hydrocarbon resin system. The composite material may include one or more oils, stabilizers, dispersants, coupling agents, pigments, thixotropic agents, rheology modifiers, tackifiers, and / or solvents.

[0021] In an exemplary embodiment, the composite material includes thermally conductive particles pretreated with phosphonic acid, thermally conductive filler particles surface-modified with phosphonic acid, and / or thermally conductive filler particles coated with phosphonic acid. The thermally conductive particles may include alumina, zinc oxide, aluminum, and / or other thermally conductive filler particles. By way of example, the composite material may include zinc oxide particles pretreated, surface-modified, and / or coated with phosphonic acid such that the composite contains about 0.01 weight percent phosphonic acid.

[0022] In an exemplary embodiment, the composite material includes a matrix comprising a crosslinked siloxane resin system. The composite material also includes zinc oxide and / or alumina fillers within the matrix, such that the composite material includes at least 90% by weight of zinc oxide and / or alumina fillers.

[0023] In an exemplary embodiment, the composite material includes a matrix including a crosslinked siloxane resin system. The composite material also includes zinc oxide filler and one or more different alumina fillers within the matrix, such that the composite material includes at least 90 weight percent of the zinc oxide filler and / or one or more different alumina fillers. The composite material also includes at least 0.067 weight percent but not more than about 0.2 weight percent of a phosphonic acid.

[0024] In an exemplary embodiment, the composite material includes a matrix including a crosslinked siloxane resin system. The composite material also includes one or more different alumina fillers within the matrix, such that the composite material includes at least 90% by weight of the one or more different alumina fillers. The composite material also includes at least 0.05% by weight but not more than about 0.2% by weight of a phosphonic acid.

[0025] In an exemplary embodiment, the composite material includes a matrix comprising a non-crosslinked siloxane resin system. The composite material also includes a zinc oxide filler and one or more different alumina fillers within the matrix, such that the composite material includes at least 90 weight percent of the zinc oxide filler and one or more different alumina fillers. The composite material also includes at least 0.09 weight percent but not more than about 0.25 weight percent of a phosphonic acid.

[0026] In an exemplary embodiment, the composite material includes a matrix including a non-crosslinked hydrocarbon resin system. The composite material also includes a zinc oxide filler and one or more different aluminum powders within the matrix, such that the composite material includes at least 90% by weight of the zinc oxide filler and one or more different alumina fillers. The composite material also includes at least 0.12% by weight but not more than about 0.25% by weight of a phosphonic acid.

[0027] Example The following examples are provided to illustrate the performance improvements achievable through the use of phosphonic acids as disclosed herein. Accordingly, the following examples are provided by way of illustration only and not by way of limitation.

[0028] Example of a cross-linked silicone resin system Exemplary formulations in weight percent (wt%) are shown below in Table 1 for five test samples, including control sample #1, which contains no phosphonic acid.

[0029] [Table 1]

[0030] Table 2 below contains the test results for five samples. Peak peel pressure, minimum bond line, and adhesive strength (Glc) were measured using an Instron MTS Criterion, Model 42, equipped with a circular platen approximately 2.5 cm (1 inch) in diameter. Samples approximately 2.5 cm (1 inch) in diameter were compressed at a rate of 0.012 mm / min to a maximum force of 450 N. The minimum bond line was the thickness of the sample at 450 N. The maximum deflection was calculated as the minimum bond line versus the initial thickness. After the maximum force was achieved, the platen was retracted at 0.012 mm / min. The peak peel pressure was recorded as the maximum force per unit area experienced during this tensile displacement. Adhesion strength was calculated from the area under the tensile stress-strain curve.

[0031] [Table 2]

[0032] Example of a cross-linked silicone resin system Exemplary formulations in weight percent (wt%) are shown in Table 3 for the control Sample 6 and Sample 7, which do not contain phosphonic acid.

[0033] [Table 3]

[0034] Table 4 below contains a summary of the physical properties of five test samples 6 through 10. As shown, formulations containing phosphonic acid at loadings up to 0.1 wt % demonstrated superior performance, including higher deflection, improved tack (measured by adhesion), reduced bondline thickness (BLT), and lower modulus, compared to those without phosphonic acid.

[0035] [Table 4]

[0036] Example of a non-crosslinked silicone resin system Exemplary formulations in weight percent (wt%) are shown below in Table 5. The preparation procedure for Samples 12-16 included adding phosphonic acid, ceramic fillers A and B, and additives (e.g., coupling agents, pigments, thixotropic agents, etc.) to silicone matrix C.

[0037] [Table 5]

[0038] The samples were prepared and transferred to an aluminum plate in an oven at 150°C under air. The samples were subsequently checked on days 3, 7, and 10, and weekly thereafter. A sample was considered embrittled if the material crumbled or cracked under gentle pressure from a metal spatula.

[0039] To measure the flow rate of the dispensable TIM material, a Nordson EFP 75cc cartridge was filled with the material, ensuring no voids remained. A piston was then placed and pressed down onto the material to remove any voids. A tapered nozzle (0.125" tip) was threaded onto the end of the cartridge. The filled cartridge was inserted into a Nordson EFD fluid dispenser assembly. The regulator on the EFD dispenser unit was set to the specified pressure (90 psi) and dispense time (20 seconds). Prior to starting the flow rate test, some material was dispensed for approximately 10 seconds to fill the nozzle with material and remove any air pockets. A new aluminum weighing pan (tared) was placed under the sample cartridge. After the material was dispensed, the weighing pan with the material was removed and the final weight was recorded. This test was repeated two more times with the remaining material in the cartridge / syringe, and the final results were averaged across all three tests.

[0040] [Table 6]

[0041] Example of a non-crosslinked silicone resin system Exemplary formulations in weight percent (wt%) are shown in Table 7 below. The preparation procedures for Examples 17-20 included pretreated phosphonic acid on ceramic filler A. Pretreated ceramic filler A, ceramic filler B, and various additives were added to silicone matrix D. Example 17 included the use of octadecylphosphonic acid. Examples 18 and 19 included the use of dodecylphosphonic acid. Example 19 included the use of tetradecylphosphonic acid. Comparative Example 1 used commercially available ceramic filler A surface-modified with propionic acid, while Comparative Example 2 used ceramic filler A surface-modified with lauric acid.

[0042] [Table 7]

[0043] The samples were aged in the same manner as if the phosphonic acid had been added directly to the formulation as described above. Table 8 below contains the test results for a control that did not contain ceramic filler A pretreated with phosphonic acid, and Examples 17, 18, 19, and 20, which contained ceramic filler A pretreated with phosphonic acid.

[0044] [Table 8]

[0045] Example of a non-crosslinked hydrocarbon resin system Table 9 includes exemplary formulations with non-crosslinked hydrocarbon resin systems. Samples with a target thickness of 200 μm were prepared for testing.

[0046] [Table 9]

[0047] Samples were prepared between liners and placed in a humidity chamber at 85°C and 85% relative humidity for 48 hours. The aged properties (thermal resistance, minimum bondline) were measured at 70°C with a TIMA5 instrument and the results are shown in Table 10 below.

[0048] [Table 10]

[0049] As shown by Table 10 above, formulations containing phosphonic acid showed superior performance compared to those without phosphonic acid, with reduced thermal resistance and minimal bondline thickness after aging at elevated temperature and humidity.

[0050] In exemplary embodiments, the thermal interface material comprises a composite material disclosed herein. Thermal interface materials include thermally conductive pads, thermally conductive gap fillers, phase change thermal interface materials, dispensable materials, bulk putties, thermal greases, sheets of thermal interface material, thermally conductive layers within optical modules, etc. For example, the thermal interface material can include thermally conductive pads having shapes such as rectangles, triangles, circles, ellipses, polygons, etc. The thermal interface material can include sheets having shapes such as rectangles, triangles, circles, ellipses, polygons, etc.

[0051] In an exemplary embodiment, the composite material includes one or more fillers including one or more of thermally conductive fillers, electrically conductive fillers, electromagnetic wave absorbing fillers, dielectric fillers, and fillers having two or more of the following properties: thermally conductive, electrically conductive, dielectric, and electromagnetic wave absorbing. In an exemplary embodiment, the composite material includes one or more fillers including one or more of alumina, zinc oxide, aluminum, carbonyl iron, silicon carbide, boron nitride, silver, aluminum nitride, barium titanate, carbon, graphite, other typical thermally conductive and / or EMI absorbing fillers, combinations thereof, and the like, wherein the one or more fillers have a D in the range of about 0.1 micrometers to about 500 micrometers. 50 It may have a median particle size.

[0052] In an exemplary embodiment, the composite material includes a thermally conductive filler and an EMI absorbing filler in a matrix, such that the composite material comprises a multi-functional EMI absorber having a first function of EMI mitigation and a second function of thermal management, or vice versa. By way of example, the filler may include one or more of functional nanoparticles, electrically conductive fillers, thermally conductive fillers, EMI or electromagnetic wave absorbing fillers, magnetic fillers, coated fillers, combinations thereof, and the like. The filler can be added to and mixed with a bulk material, including a matrix material, thereby providing a mixture of the filler and base or matrix material. Examples of 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, ferrite, magnetic alloys, magnetic powders, magnetic flakes, magnetic particles, nickel-based alloys and powders, chromium alloys, oxides, copper, zinc oxide, alumina, graphite, ceramics, silicon carbide, manganese zinc, glass fibers, carbon nanotubes (e.g., single-walled carbon nanotubes, multi-walled carbon nanotubes, and / or carbon nanostructures), combinations thereof, etc. The filler may comprise one or more of granules, spheroids, microspheres, ellipsoids, irregular spheroids, strands, flakes, powders, nanotubes, and / or combinations of any or all of these shapes. Additionally, exemplary embodiments may also include different grades (eg, different sizes, different purities, different shapes, etc.) of the same (or different) fillers.

[0053] In an exemplary embodiment, the composite material has a high thermal conductivity of at least 1 Watt per meter per Kelvin (W / mK) as measured by a hot-disk thermal constant analyzer. For example, the composite material may have a thermal conductivity of 1 W / mK, 2 W / mK, 3 W / mK, 4 W / mK, 5 W / mK, or greater than 5 W / mK. To determine thermal conductivity, a hot-disk instrument can be used that measures thermal conductivity, thermal diffusivity, and specific heat capacity using the Transient Plane Source Method (TPS). For background, this technique is addressed in ISO 22007-2:2008, Part 2. This technique utilizes a planar sensor and a specialized mathematical model that describes thermal conductivity, combined with electronics that enable this method to be used to measure thermal transfer properties. This technique typically covers a thermal conductivity range of 0.01 to 500 W / m / K. The TPS technique typically employs two sample halves that sandwich a sensor. This method can also be used in a single-sided configuration. This technique is versatile, fast, and covers measurements on solids, pastes, thin films, and liquids. It can test both isotropic and anisotropic materials. The flat sensor contains a continuous double helix of conductive nickel metal etched from a thin foil. The nickel helix is ​​placed between two layers of thin Kapton® polyimide film. During measurement, a constant electrical effect passes through the conductive helix, increasing the sensor temperature. The generated heat dissipates into the sample on both sides of the sensor at a rate dependent on the material's thermal conductivity properties. By recording the temperature versus time response at the sensor, the thermal conductivity, thermal diffusivity, and specific heat capacity of the material can be calculated.

[0054] In an exemplary embodiment, a device or system includes a composite material disclosed herein that is used to manage the thermal properties of the device or system. Also disclosed is an exemplary method of using phosphonic acid to improve the performance of a composite material useful for heat and / or electromagnetic interference (EMI) management. In an exemplary embodiment, the method includes including about 0.01 weight percent to about 3 weight percent of phosphonic acid in a composite material, based on the total weight of the composite material, in an amount sufficient to improve the performance of the composite material (compared to another composite material having substantially the same formulation but without the phosphonic acid). The method may include pretreating, surface modifying, and / or coating one or more fillers with the phosphonic acid. Additionally or alternatively, the method may include adding the phosphonic acid as an additive to the composite material formulation. The composite material may include a thermal management and / or electromagnetic interference (EMI) mitigation material, such as a thermal interface material (TIM), an EMI absorber material, a thermally conductive EMI absorber material, an electrically conductive material, or a combination thereof.

[0055] In an exemplary embodiment, the phosphonic acid may include an organic moiety bonded directly to the phosphorus atom through a carbon atom. Preferred phosphonic acids have organic ligands consisting of an aliphatic hydrocarbon moiety of about 2 to 20 carbon atoms. Suitable aliphatic organic ligands may be linear, branched, star-shaped, or cyclic, saturated or unsaturated, and optionally substituted with one or more functional groups, including silyl, siloxane, fluoroalkyl, aromatic, thiol, alcohol, carboxylic acid, amine, or amide substituents. Other suitable phosphonic acids may have organic ligands with oligomeric or polymeric structures in linear, branched, star-shaped, or cyclic configurations containing repeating units of polyacrylate, polymethacrylate, polystyrene, polysiloxane, polyester, polyamide, polybutadiene, hydrogenated polybutadiene, polypropylene, polyethylene, or other chemicals. The phosphonic acid may contain one or more phosphonic acid groups. The phosphonic acid may include one or more of octadecylphosphonic acid, tetradecylphosphonic acid, and / or dodecylphosphonic acid.

[0056] In an exemplary method, the use of a phosphonic acid improves the performance of a composite (compared to another composite having substantially the same formulation but without the phosphonic acid) by one or more of improving the rheological properties of the composite, improving the aging properties of the composite, improving the shelf life of the composite, improving tack / adhesion, and / or reducing the diffusion of migrating materials, if any, from the composite.

[0057] In an exemplary embodiment, an electronic device includes a composite material as disclosed herein usable as a thermal interface material (e.g., a thermally conductive pad, a thermally conductive gap filler, a phase change thermal interface material, a dispensable material, a bulk putty, a thermal grease, a sheet of thermal interface material, a thermally conductive layer in an optical module, etc.) and a heat source. The composite material is positioned relative to a heat source to establish at least a portion of a thermally conductive heat path from the heat source through the composite material. The composite material may also be configured to be EMI absorptive and / or conductive, such that the composite material is also operable to mitigate and / or manage EMI within the electronic device.

[0058] In an exemplary embodiment, an electronic device includes a heat source, a heat removal / dissipation structure, and a composite material disclosed herein usable as a thermal interface material (e.g., a thermally conductive pad, a thermally conductive gap filler, a phase change thermal interface material, a dispensable material, a bulk putty, a thermal grease, a sheet of thermal interface material, a thermally conductive layer in an optical module, etc.). The composite material 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. The composite material may also be configured to be EMI absorptive and / or conductive, such that the composite material is also operable to mitigate and / or manage EMI within the electronic device.

[0059] In an exemplary embodiment, an electronic device includes a heat source, a board-level shield, and a composite material disclosed herein usable as a thermal interface material (e.g., a thermally conductive pad, a thermally conductive gap filler, a phase change thermal interface material, a dispensable material, a bulk putty, a thermal grease, a sheet of thermal interface material, a thermally conductive layer in an optical module, etc.). The composite material is positioned relative to the heat source and the board-level shield to establish at least a portion of a thermally conductive heat path between the heat source and the board-level shield. The composite material may also be configured to be EMI absorptive and / or conductive, such that the composite material is also operable to mitigate and / or manage EMI within the electronic device.

[0060] In an exemplary embodiment, an electronic device includes a heat source, a board-level shield, a heat removal / dissipation structure, and first and second composite materials usable as thermal interface materials (e.g., thermally conductive pads, thermally conductive gap fillers, phase change thermal interface materials, dispensable materials, bulk putty, thermal grease, sheets of thermal interface material, thermally conductive layers in optical modules, etc.). The first composite material is disposed relative to the heat source and the board-level shield to establish at least a portion of a first thermally conductive heat path between the heat source and the board-level shield. The second composite material is disposed relative to the board-level shield and the heat removal / dissipation structure to establish at least a portion of a second thermally conductive heat path between the board-level shield and the heat removal / dissipation structure. The first and / or second composite materials may also be configured to be EMI absorptive and / or conductive, such that the first and / or second composite materials are also operable to mitigate and / or manage EMI within the electronic device.

[0061] In an exemplary embodiment, an electronic device includes an integrated circuit, a board-level shield, a heat sink, and first and second composite materials usable as thermal interface materials (e.g., thermally conductive pads, thermally conductive gap fillers, phase change thermal interface materials, dispensable materials, bulk putty, thermal grease, sheets of thermal interface material, thermally conductive layers in optical modules, etc.). The first composite material is disposed relative to the integrated circuit and the board-level shield to establish at least a portion of a first thermally conductive heat path between the integrated circuit and the board-level shield. The second composite material is disposed relative to the board-level shield and the heat sink to establish at least a portion of a second thermally conductive heat path between the board-level shield and the heat sink. The first and / or second composite materials may also be configured to be EMI absorptive and / or conductive, such that the first and / or second composite materials are also operable to mitigate and / or manage EMI within the electronic device.

[0062] The exemplary embodiments disclosed herein may be used in a wide range of industries (e.g., automotive, consumer goods, industrial, datacom / telecommunications, aerospace / defense, etc.) and applications (e.g., automotive electronics, automotive advanced driver assistance systems (ADAS), automotive powertrain / electronic control units (ECUs), automotive infotainment, routers, hard disk drives, solid state drives, wireless infrastructure, drones / satellites, gaming systems, smart home devices, notebooks / tablets / portable devices, etc.). Furthermore, the exemplary embodiments disclosed herein may be used in a wide range of heat sources, electronic devices, and / or heat removal / dissipation structures or components (e.g., heat spreaders, heat sinks, heat pipes, vapor chambers, external device cases, 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.), solid-state drives (SSDs), memory in video cards, set-top boxes, televisions, gaming systems, automotive electronics used in autonomous driving (ADAS) (e.g., radar, multi-domain controllers, cameras, etc.), CPUs, die-in-underfill, semiconductor devices, flip-chip devices, graphics processing units (GPUs), digital signal processors (DSPs), multiprocessor systems, integrated circuits (ICs), multi-core processors, etc. Generally, a heat source may include any component or device that has a higher temperature than the thermal management and / or EMI mitigation material or that provides or transfers heat to the thermal management and / or EMI mitigation material, whether the heat is generated by the heat source or simply transfers through or via the heat source. Thus, aspects of the present disclosure should not be limited to use with a single type of heat source, electronic device, heat removal / dissipation structure, etc.

[0063] The 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 the present disclosure. It will be apparent to those skilled in the art that the use of specific details is not necessary, that the exemplary embodiments can be embodied in many different forms, and that neither should be construed as limiting the scope of the present disclosure. In some exemplary embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. Furthermore, advantages and improvements that may be achieved in one or more exemplary embodiments of the present disclosure are provided for illustrative purposes only and do not limit the scope of the present disclosure, as an exemplary embodiment of the present disclosure may provide all or none of the above advantages and improvements and still be within the scope of the present disclosure.

[0064] The specific dimensions, specific materials, and / or specific shapes disclosed herein are exemplary in nature and do not limit the scope of the present disclosure. The disclosure herein of a specific value and a specific range of values ​​for a given parameter does not exclude other values ​​and ranges of values ​​that may be useful in one or more examples disclosed herein. Furthermore, it is contemplated that any two specific values ​​for a particular parameter described herein may define the endpoints of a range of values ​​that may be suitable for the given parameter (i.e., the disclosure of a first and a second value for a given parameter can be interpreted as disclosing that any value between the first and second values ​​can be used for the particular parameter). For example, if parameter X is exemplified herein as having a value A and also as having a value Z, it is contemplated that parameter X may have a range of values ​​from about A to about Z. Similarly, the disclosure of two or more ranges of values ​​for a parameter (whether such ranges are nested, overlapping, or separate) is contemplated to encompass all possible combinations of ranges of values ​​that may be claimed using the endpoints of the disclosed ranges. For example, if a parameter X is exemplified herein as having a value in the range of 1 to 10, or 2 to 9, or 3 to 8, it is also contemplated that the parameter X may have other ranges of values, including 1 to 9, 1 to 8, 1 to 3, 1 to 2, 2 to 10, 2 to 8, 2 to 3, 3 to 10, and 3 to 9.

[0065] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. For example, when permissive phrases such as "may include" or "may include" are used herein, at least one embodiment includes the feature. As used herein, the singular forms "a," "an," and "the" may be intended to include the plural forms as well, unless the context clearly dictates otherwise. The terms "comprise," "include," and "have" are inclusive and thus specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Method steps, processes, and operations described herein should not be construed as necessarily requiring their performance in the particular order described or illustrated, unless specifically identified as an order of performance. It should also be understood that additional or alternative steps may be employed.

[0066] When an element or layer is described as "on," "engaged with," "connected to," or "bonded to" another element or layer, it may be directly on, engaged with, connected to, or bonded to that other element or layer, or to intervening elements or layers that may be present. In contrast, when an element is described as "directly on," "directly engaged with," "directly connected to," or "directly bonded to" another element or layer, there may be no intervening elements or layers. Other words used to describe relationships between elements should be interpreted in a similar manner (e.g., "between" and "directly between," "adjacent" and "directly adjacent," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0067] The term "about," when applied to a value, indicates that the calculation or measurement allows for slight imprecision in the value (approximately or reasonably close to the value, depending on the approach to the accuracy of the value; approximately). If, for some reason, the imprecision provided by "about" is not understood in this ordinary sense in the art, "about," as used herein, refers to at least the variation that can result from ordinary methods of measuring or using such parameters. For example, the terms "generally," "about," and "substantially" can be used herein to mean within manufacturing tolerances. Alternatively, for example, the term "about," as used herein, when used to vary the amounts of components or reactants of the present invention, refers to variations in numerical values ​​that can occur, for example, in typical measuring and handling procedures used in producing concentrates or solutions in the real world, through inadvertent errors in these procedures, or through differences in the manufacture, source, or purity of components used to make the composition or carry out the method. The term "about" also encompasses amounts that differ due to different equilibrium conditions of a composition resulting from a particular initial mixture. Numerical quantities and equivalents are included regardless of whether they are modified by the term "about."

[0068] Terms such as "first," "second," and "third" may be used herein to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or section from another region, layer, or section. When used herein, terms such as "first," "second," and other numerical terms do not imply an order or sequence unless clearly indicated by context. Thus, a first element, component, region, layer, or section discussed below could be referred to as a second element, component, region, layer, or section without departing from the teachings of the exemplary embodiments.

[0069] Spatially relative terms such as "inside," "outside," "below," "down," "lower," "upper," "above," and the like may be used herein to facilitate the description of the relationship of one element or feature to another, as shown in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation shown in the figures. For example, if the device in the figures is turned over, elements described as "below" or "below" other elements or features would then become "above" the other elements or features. Thus, the example term "below" can encompass both an orientation of above and below. The device may be oriented differently (rotated 90 degrees or in another orientation), and the spatially relative descriptors used herein may be interpreted accordingly.

[0070] 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. Individual elements, intended or described uses, or features of a particular embodiment are in most cases not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in selected embodiments even if not specifically shown or described. The same can also be modified in many ways. Such modifications should not be considered a departure from the disclosure, and all such variations are intended to be included within the scope of the disclosure.

Claims

1. 1. A composite material useful for thermal and / or electromagnetic interference (EMI) management, comprising: The Matrix and one or more fillers in a matrix; Phosphonic acid and Composite materials, including:

2. 2. The composite material of claim 1, wherein the one or more fillers are pretreated with the phosphonic acid, surface modified with the phosphonic acid, coated with the phosphonic acid, or two or more thereof.

3. 10. The composite material of claim 1, wherein the phosphonic acid is an additive added directly to the composite material formulation.

4. 10. The composite material of claim 1, wherein the one or more fillers are pretreated, surface modified, or coated with the phosphonic acid, such that the composite material comprises from about 0.01 weight percent to about 3 weight percent of the phosphonic acid, based on the total weight of the composite material.

5. 10. The composite material of claim 1, wherein the composite material comprises from about 0.01 weight percent to about 3 weight percent of a phosphonic acid, based on the total weight of the composite material.

6. the phosphonic acid comprises an organic moiety directly bonded to the phosphorus atom via a carbon atom; and / or the phosphonic acid has an aliphatic organic ligand having an aliphatic hydrocarbon moiety of about 2 to 20 carbon atoms, whereby the aliphatic organic ligand can be of a linear, branched, star-shaped, or cyclic structure and / or saturated or unsaturated; The composite material of claim 1.

7. the phosphonic acid has organic ligands with oligomeric or polymeric structures, linear, branched, star-shaped, or cyclic, containing repeating units of polyacrylate, polymethacrylate, polystyrene, polysiloxane, polyester, polyamide, polybutadiene, hydrogenated polybutadiene, polypropylene, polyethylene, or other chemicals; and / or The phosphonic acid comprises one or more phosphonic acid groups. The composite material of claim 1.

8. The phosphonic acid is octadecylphosphonic acid, tetradecylphosphonic acid, and / or Dodecylphosphonic acid 10. The composite material of claim 1, comprising one or more of:

9. at least about 0.05% by weight but not more than about 0.25% by weight of said phosphonic acid; or at least about 0.1 wt. % but not more than about 0.3 wt. % of said phosphonic acid 2. The composite material of claim 1, comprising:

10. The phosphonic acid is improving the rheological properties of the composite material; improving the aging properties of the composite material; improving the shelf life of the composite material; improving tack / adhesion, and / or reducing the diffusion of any material that migrates from said composite material; 10. The composite material of claim 1, wherein the composite material has a composition that is at least phosphonic acid-free and at least one of:

11. 10. The composite material of any one of claims 1 to 9, wherein the phosphonic acid increases the flow rate (grams / minute) of the composite material compared to another composite material having substantially the same formulation but without the phosphonic acid.

12. The phosphonic acid is 150°C or 200°C Relative humidity 85% and temperature 40°C, 85 percent relative humidity and 85°C temperature, and / or Relative humidity 85% and temperature 130°C 10. The composite material of claim 1, wherein the composite material has an increased time to embrittlement compared to another composite material having substantially the same formulation but not comprising phosphonic acid, wherein the time to embrittlement is determined by measuring one or more of heat resistance, Shore hardness, and / or bend radius.

13. 10. The composite material of any one of claims 1 to 9, wherein the phosphonic acid enables the composite material to achieve a higher deflection compared to another composite material having substantially the same formulation but without the phosphonic acid.

14. 10. The composite material of any one of claims 1 to 9, wherein the phosphonic acid provides improved adhesion compared to another composite material having substantially the same formulation but without the phosphonic acid, the adhesion being determined by measuring the peak peel pressure and / or adhesive force of the composite material.

15. 10. The composite material of any one of claims 1 to 9, wherein the phosphonic acid reduces the minimum bond line thickness (BLT) of the composite material at comparable pressures compared to another composite material having substantially the same formulation but without the phosphonic acid.

16. 10. The composite material of any one of claims 1 to 9, wherein the phosphonic acid reduces the thermal resistance of the composite material having substantially the same formulation but without the phosphonic acid.

17. 10. The composite material of any one of claims 1 to 9, wherein the phosphonic acid reduces the modulus of the composite material compared to another composite material having substantially the same formulation but without the phosphonic acid.

18. The one or more fillers are thermally conductive filler, Conductive filler, Electromagnetic wave absorbing filler, a dielectric filler, and A filler having two or more of the following properties: thermal conductivity, electrical conductivity, dielectric property, and electromagnetic wave absorption property.

10. The composite material according to claim 1, comprising one or more of:

19. the one or more fillers comprise one or more of alumina, zinc oxide, aluminum, carbonyl iron, silicon carbide, boron nitride, silver, aluminum nitride, barium titanate, carbon, and graphite; and / or The one or more fillers have a D in the range of about 0.1 micrometers to about 500 micrometers. ５０ The composite material of any one of claims 1 to 9, having a median particle size.

20. 10. The composite material of any one of claims 1 to 9, wherein the matrix comprises a polymer-based resin system such as a cross-linked siloxane resin system, a non-cross-linked siloxane resin system, a non-cross-linked hydrocarbon resin system, or a cross-linked hydrocarbon resin system.

21. 10. The composite material of claim 1, wherein the one or more fillers comprise thermally conductive particles comprising one or more of alumina, zinc oxide, and / or aluminum, the thermally conductive particles being pretreated with, surface modified with, and / or coated with the phosphonic acid.

22. the matrix comprises a crosslinked siloxane resin system; and 10. The composite material of any one of claims 1 to 9, wherein the one or more fillers comprise zinc oxide filler and / or alumina filler in the matrix such that the composite material comprises at least 90 weight percent zinc oxide filler and / or alumina filler.

23. the composite material is a thermal interface material, an EMI absorber material, a thermally conductive absorber material, an electrically conductive material, or a combination of two or more thereof; and / or The composite material of any one of claims 1 to 9, wherein the composite material is a thermal phase change material, a thermal putty, a thermal grease, a dispensable thermal interface material, and / or a thermal gap filler pad.

24. A device or system comprising a composite material according to any one of claims 1 to 9, used to manage the thermal properties of the device or system.

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