High temperature insulating composite material and articles thereof

Abstract

Described herein are high temperature insulating composites and articles formed therefrom that are conformable, low dusting, and provide a thermal conductivity of 25 wM / mK at ambient conditions, as well as function as a heat propagation barrier when exposed to temperatures sufficient to partially or completely volatilize the fibrillated polymer matrix within the high temperature insulating composite.

Description

[Technical Field]

[0001] Field The present disclosure relates generally to high temperature insulating materials and articles thereof, and more particularly to high temperature insulating composites and articles thereof that can maintain insulating and thermal barrier properties when exposed to high temperatures. [Background technology]

[0002] background High-temperature insulating materials are often incorporated into electronic devices to protect sensitive components therein or to protect the user from heat sources that may cause discomfort to the user. Certain applications, such as battery cell packs, may benefit from the use of high-temperature insulating materials that can also function as high-temperature insulating composites capable of withstanding extremely high temperatures, such as a lithium-ion battery thermal runaway event. However, many conventional insulating materials can be difficult to handle, difficult to form into the desired shape or thickness for the intended application, and / or can suffer from excessive dusting.

[0003] Various protective articles require insulating materials that are thin, strong, conformable, compressible, and have insulating properties (e.g., thermal conductivity sufficient for the intended application). However, some insulating materials are used in applications or devices where a high temperature event may occur, such as when a component within the device malfunctions and releases a sufficient amount of energy to cause an adverse event (e.g., a thermal runaway event). The resulting temperature increase may damage other components inside or outside the device. In some embodiments, the high temperature event may be sufficient to damage a second component, and damage to the second component may cause a second high temperature event (e.g., an adjacent cell in a high-energy battery (e.g., a lithium-ion battery)).

[0004] U.S. Patent No. 7,118,801 to Ristic-Lehmann et al. teaches a conformable insulating material useful for insulating clothing, containers, pipes, electronic devices, and other applications. Ristic-Lehmann's conformable material contains at least 40 wt% aerogel particles and up to 60 wt% polytetrafluoroethylene (PTFE) particles in the form of a putty or powder with a thermal conductivity of 25 milliwatts per meter Kelvin (mW / mK) or less at atmospheric conditions (298.15 K and 1013 kPa). The conformable material can contain up to 10 wt% additional components (based on the total mass of the composite), such as opacifiers, dyes, fibers, and polymers. However, Ristic-Lehmann et al. does not teach an insulating composite that also functions as a heat-transfer barrier for use in high-temperature applications.

[0005] U.S. Patent Publication No. 2017 / 0203552 A1 to D'Arcy et al. describes an insulating material comprising at least 20 wt. % polymer matrix (based on the total weight of the composite), at least 30 wt. % aerogel particles, and 0.5-15 wt. % expanded microspheres. The thermal conductivity of the insulating material is less than 40 mW / mK at atmospheric conditions. D'Arcy et al. does not teach an insulating composite that can also function as a heat transfer barrier for use in high-temperature applications.

[0006] Therefore, a need remains for a high temperature insulating composite that is suitable for use in high temperature applications, is thin, conformable, insulating, and can perform as a high temperature insulating composite when exposed to high temperatures. Summary of the Invention

[0007] Abstract In one embodiment ("Embodiment 1"), a high temperature insulating composite includes up to 50 wt% of a fibrillated polymer matrix, more than 40 wt% of aerogel particles, and a total of more than 10 wt% of additional particulate components selected from one or more opacifying agents, one or more reinforcing fibers, one or more expandable microspheres, and any combination thereof. The weight percentages are based on the total weight of the final high temperature insulating composite. The aerogel particles and additional particulate components are durably entangled within the fibrillated polymer matrix.

[0008] In addition to embodiment 1, according to another embodiment ("embodiment 2"), the high temperature insulating composite is in the form of a tube, tape, or sheet having a thickness or tube wall thickness of 5 mm or less.

[0009] According to another embodiment (“Embodiment 3”) in addition to Embodiment 1 or Embodiment 2, the fibrillating polymer matrix comprises a polyolefin, an ultra-high molecular weight polyethylene, a fluoropolymer, polytetrafluoroethylene, expanded polytetrafluoroethylene, a polyurethane, a polyester, a polyamide, or any combination thereof.

[0010] According to another embodiment (“Aspect 4”) in addition to any one of Aspects 1-3, the polymer is expanded polytetrafluoroethylene (ePTFE), expanded (expanded, expanded, stretched, or foamed) ultra-high molecular weight polyethylene (ePE), or a combination thereof.

[0011] According to another embodiment ("Embodiment 5"), in addition to any one of Embodiments 1-4, the total of the additional particle components comprises less than 10% of one or more opacifying agents.

[0012] According to another embodiment ("embodiment 6"), in addition to any one of embodiments 1-5, the additional component comprises at least 2 wt% of one or more reinforcing fibers.

[0013] According to another embodiment (“Embodiment 7”) in addition to any one of Embodiments 1-6, the additional particulate component comprises up to 30 wt % expandable microspheres.

[0014] According to another embodiment (“Embodiment 8”), in addition to any one of Embodiments 1-7, the opacifying agent is selected from carbon black, titanium dioxide, aluminum oxide, zirconium dioxide, iron oxide, silicon carbide, molybdenum disilicide, manganese oxide, polydialkylsiloxane in which the alkyl group contains 1 to 7 carbon atoms, or any combination thereof.

[0015] According to another embodiment ("embodiment 9"), in addition to any one of embodiments 1-8, the one or more reinforcing fibers include carbon fibers, glass fibers, aluminoborosilicate fibers, or a combination thereof.

[0016] In another embodiment (“Aspect 10”), a high temperature insulating composite comprises less than 50 wt. % fibrillated polymer matrix, less than 80 wt. % aerogel particles, greater than 10 wt. % at least one opacifying agent, no more than 25 wt. % reinforcing fibers, and less than 20 wt. % expandable microspheres, where the weight percentages are based on the total weight of the final high temperature insulating composite article, and wherein the aerogel particles and additional particulate components are durably entangled within the fibrillated polymer matrix.

[0017] In addition to Example 10, according to another example ("Example 11"), the high temperature insulating composite is in the form of a tube, tape, or sheet having a thickness or tube wall thickness of 5 mm or less.

[0018] According to another embodiment (“Aspect 12”), further to Aspect 10 or Aspect 11, the fibrillated polymer matrix comprises a polyolefin, an ultra-high molecular weight polyethylene, a fluoropolymer, polytetrafluoroethylene, expanded polytetrafluoroethylene, a polyurethane, a polyester, a polyamide, or any combination thereof.

[0019] According to another embodiment (“Aspect 13”) in addition to any one of Aspects 10-12, the polymer is expanded polytetrafluoroethylene (ePTFE), expanded ultra-high molecular weight polyethylene (ePE), or a combination thereof.

[0020] According to another embodiment ("embodiment 14"), in addition to any one of embodiments 10-13, the additional component includes at least 2 wt% of one or more reinforcing fibers.

[0021] According to another embodiment (“embodiment 15”) in addition to any one of embodiments 10-14, the additional particulate component comprises up to 30 wt % expandable microspheres.

[0022] According to another embodiment (“Aspect 16”), in addition to any one of Aspects 10-15, the opacifying agent is selected from carbon black, titanium dioxide, aluminum oxide, zirconium dioxide, iron oxide, silicon carbide, molybdenum disilicide, manganese oxide, polydialkylsiloxane in which the alkyl group contains 1 to 4 carbon atoms, or any combination thereof.

[0023] According to another embodiment ("embodiment 17"), in addition to any one of embodiments 10-16, the one or more reinforcing fibers include carbon fibers, glass fibers, aluminoborosilicate fibers, or a combination thereof.

[0024] In another embodiment ("Embodiment 18"), an article comprises the high temperature insulating composite of claim 1.

[0025] In another embodiment ("embodiment 19"), an article comprises the high temperature insulating composite of claim 10.

[0026] In another embodiment ("embodiment 20"), the high temperature insulating composite of any of claims 1 to 9 is used to prevent heat propagation in a lithium ion battery.

[0027] In another embodiment ("embodiment 21"), the high-temperature insulating composite of any one of claims 10 to 16 is used to prevent heat propagation in a lithium-ion battery.

[0028] In one embodiment ("Embodiment 22"), an article includes a first component capable of generating a high temperature event having a first temperature, a second component protected from exposure to the first temperature, and a high temperature insulating composite disposed between the first and second components. The high temperature insulating composite has a first side facing the first component and an opposite side facing the second component. The high temperature insulating composite includes at least about 40 wt% aerogel particles, up to about 60 wt% fibrillated polymer matrix, and 1 wt% to 45 wt% of one or more additional particulate components selected from one or more opacifying agents, one or more reinforcing fibers, one or more expandable microspheres, and any combination thereof. The weight percents are based on the total weight percent of the high temperature insulating composite in its final state, and the aerogel particles and the additional particulate components are durably entangled within the fibrillated polymer matrix.

[0029] In one embodiment ("Embodiment 23"), the heat spread assay comprises providing an approximately 1 mm thick sheet of high temperature insulating composite having a first side and a second side; placing the first side of the sheet of high temperature insulating composite between a heated stainless steel block having a mass of approximately 905 g and a heat spread assay between a heated stainless steel block having a mass of approximately 106.4 cm 2 (14 cm x 7.6 cm), a temperature of about 800°C, a pressure of about 42.3 kPa for 30 minutes, and measuring the temperature of the second side during the 30 minutes of the compressive contact step, wherein an adequate heat transfer barrier is defined by a maximum measured temperature of less than 215°C.

[0030] In one embodiment (“Embodiment 24”), a multilayer, high-temperature, thermal insulating composite includes a first layer and a second layer. The first layer and second layer each include at least about 40 wt. % aerogel particles, at most about 60 wt. % fibrillated polymer matrix, and between 1 wt. % and 45 wt. % of one or more additional particle components selected from one or more opacifying agents, one or more reinforcing fibers, one or more expandable microspheres, and any combination thereof. The one or more additional particle components vary across a first thickness of the first layer in one or more of chemical composition, particle size, and particle size distribution, and the one or more additional particle components vary across a second thickness of the second layer in one or more of chemical composition, particle size, and / or particle size distribution.

[0031] In addition to Aspect 24, according to another aspect (“Aspect 25”), the composition includes a third layer, the third layer including one or more additional particle components that differ in one or more of chemical composition, particle size, and / or particle size distribution across the thickness of the third layer.

[0032] In addition to Example 25, according to another example ("Example 26"), the one or more additional components are opacifying agents, the first layer comprising an opacifying agent having a first particle size distribution therein, the second layer comprising an opacifying agent having a second particle size distribution therein, and the third layer comprising an opacifying agent having a third particle size distribution. [Brief explanation of the drawings]

[0033] BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification, illustrate embodiments and, together with the description, serve to explain the principles of the disclosure.

[0034] [Figure 1A] FIG. 1A is a schematic cross-sectional view of a high temperature insulating composite having varying particle composition through its thickness, according to some embodiments.

[0035] [Figure 1B]FIG. 1B is a schematic cross-sectional view of a multi-layer high temperature insulating composite having different particle size distributions in different layers, according to some embodiments.

[0036] [Figure 2] FIG. 2 is a schematic diagram of a test system used to evaluate the performance of samples in a heat propagation protective barrier test, according to some embodiments.

[0037] [Figure 3] FIG. 3 is a side schematic view of a contact compression zone when testing a sample in a Heat Propagation Protective Barrier Test, according to some embodiments.

[0038] [Figure 4] FIG. 4 is a graph of a representative plot of the relationship between the heat storage temperature and the average temperature measured on the opposite side of a composite insulation sample after 45 minutes (after contact) with the heat storage, as described in the Heat Transfer Protection Barrier Test, according to some embodiments.

[0039] [Figure 5] FIG. 5 is a graph illustrating thickness-normalized compressive deflection versus compressive stress data for Samples 1-4 of Example 2, according to some embodiments.

[0040] [Figure 6] FIG. 6 is a graph showing insulation thickness vs. compressive stress data for Samples 1-3 of Example 2, according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0041] Detailed Description Those skilled in the art will readily appreciate that the various aspects of the present disclosure may be implemented by any number of methods and apparatus configured to perform the intended functions. It should also be noted that the accompanying drawings referred to herein are not necessarily drawn to scale and may be exaggerated to illustrate various aspects of the present disclosure, and in that regard, the drawings should not be construed as limiting.

[0042] As used herein, "ultra-high molecular weight" refers to a polymer having a number average molecular weight in the range of 3,000,000 to 10,000,000 g / mol.

[0043] As used herein, the term "mass percent" or "wt%" is intended to indicate the mass percent of that component based on the total mass percent of the final high temperature insulation composite (i.e., after the lubricant has been removed). "Wt%" can be defined as the mass of the component divided by the total mass of the high temperature insulation components (after the lubricant has been removed) multiplied by 100.

[0044] As used herein, the term "high temperature" refers to a temperature sufficient to partially or completely decompose (e.g., depolymerize, chain scission, and / or volatilize) the fibrillated polymer matrix within the high temperature insulating composites described herein. In one embodiment, "high temperature" is a temperature sufficient to partially or completely volatilize the fibrillated polymer within the high temperature insulating composite.

[0045] As used herein, the term "high temperature event" is intended to refer to a situation in which temperatures are reached that are sufficient to partially or completely volatilize the fibrillated polymer matrix within a high temperature insulating composite.

[0046] The high temperature insulating composite (1) provides a thermal conductivity of 25 milliwatts per meter Kelvin (mW / mK) or less at atmospheric conditions (298.15 K and 101.3 kPa) before exposure to a high temperature event, and (2) functions as a protective heat propagation barrier when exposed to a high temperature event at a temperature sufficient to partially or completely volatilize the fibrillated polymer binder within the high temperature insulating composite. It should be understood that the phrases "fibrillated polymer matrix" and "fibrillated polymer binder" may be used interchangeably herein.

[0047] The high temperature insulating composites are suitable for use in applications and / or articles having at least one heat-sensitive component and are capable of releasing sufficient energy (typically upon failure of that component) to bring the temperature to partially or completely volatilize (e.g., decompose) the fibrillated polymer matrix within the high temperature insulating composite, while still providing sufficient insulation to protect one or more adjacent heat-sensitive components from damage. This is particularly important in applications / articles where a first high temperature thermal event (typically associated with component failure) having temperatures potentially damaging to adjacent heat-sensitive components can occur, resulting in a second high temperature thermal event, etc. (e.g., the propagation of a runaway high temperature thermal event in a high energy battery). The high temperature insulating composite protectively slows or prevents the propagation of thermal energy from a first side of the high temperature insulating composite to a second, opposite side of the high temperature insulating composite, such that one or more heat-sensitive components on the second, opposite side of the high temperature insulating composite are sufficiently protected from a high temperature thermal event such that adjacent heat-sensitive components do not undergo a thermal runaway event or the rate of thermal runaway propagation is reduced.

[0048] In certain applications, such as certain high-energy batteries, high-temperature thermal events may occur. As discussed above, high-temperature thermal events may be sufficient to damage adjacent heat-sensitive components, including situations where exposure of adjacent heat-sensitive components to a high-temperature event may cause a secondary high-temperature event in the adjacent heat-sensitive components (e.g., a runaway event in a failed lithium-ion battery). Therefore, an insulating barrier is needed to protect adjacent heat-sensitive components from exposure to high (damaging) temperatures. As demonstrated in the assays described herein, one side (the "challenge side") of a thin sheet (approximately 1 mm thick) of high-temperature insulating composite was placed in compression contact with a block of stainless steel heated to approximately 800°C (i.e., a temperature sufficient to volatilize the fibrillated polymer). The opposite side (the "protected side") of the thin sheet experienced a significantly lower maximum temperature. In one embodiment, a high-temperature insulating composite capable of functioning as a heat propagation barrier is one that can limit the maximum temperature of the protected side to 215°C or less when the challenge side is exposed to a temperature of approximately 800°C according to the Heat Propagation Protective Barrier Test described below.

[0049] The temperature required to partially or completely volatilize the fibrillating polymer binder in a high temperature insulating composite varies with the choice of fibrillating polymer. Thus, a high temperature insulating composite is one that can provide at least about 70%, at least about 73%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, or at least 95% (100% being the maximum or sum equals 100%) reduction in the maximum observed temperature (i.e., on the protective / insulating side) when exposed to a temperature (i.e., on the challenge side) that at least partially volatilizes the fibrillating polymer matrix. In further embodiments, the challenge side temperature provides sufficient thermal energy to completely volatilize the fibrillating polymer matrix.

[0050] In another embodiment, the high temperature event is a temperature of at least about 250°C, at least about 300°C, at least about 350°C, at least about 400°C, at least about 450°C, at least about 500°C, at least about 550°C, at least about 600°C, at least about 650°C, at least about 700°C, at least about 750°C, at least about 800°C, or at least about 850°C that fibrillates polymer molecules in the high temperature insulating composite. and a temperature that partially or completely volatilizes the high temperature insulating composite, wherein the maximum temperature on the opposite side of the high temperature insulating composite is about 225° C. or less, about 220° C. or less, about 215° C. or less, about 210° C. or less, about 205° C. or less, about 200° C. or less, about 195° C. or less, about 190° C. or less, about 185° C. or less, about 180° C. or less, about 175° C., about 170° C. or less, about 165° C. or less, about 160° C. or less, about 155° C. or less, about 150° C. or less, or about 145° C. In at least one embodiment, the high temperature thermal event is at least 800° C. on the challenge side of the high temperature insulating composite, and the maximum temperature on the opposite side of the high temperature insulating composite (the protected / insulated side) is 215° C. or less.

[0051] High-Temperature Insulating Composites The high temperature insulating composites of the present disclosure include a fibrillated polymer matrix, high temperature insulating aerogel particles, one or more opacifying agents, and optionally, reinforcing fibers and / or expandable microspheres and / or additional particulate components. In one embodiment, the high temperature insulating composite includes greater than 10 wt% of the opacifying agent, and / or reinforcing fibers and / or expandable microspheres. As noted above, the term percent by weight (wt%) refers to a percent of the total mass of the high temperature insulating composite. In another embodiment, the high temperature insulating composite includes greater than 10 wt% of the opacifying agent.

[0052] The aerogel particles, one or more opacifying agents, reinforcing fibers and / or expandable microspheres and / or additional particulate components are durably entangled within the fibrillated polymer matrix, and the thermal conductivity of the high-temperature insulating composite is 25 milliwatts per meter Kelvin (mW / mK), 23 mW / mK, 21 mW / mK, 19 mW / mK, or 17 mW / mK or less at atmospheric conditions (298.15 K and 101.3 kPa). As used herein, the phrase "durably entangled" is intended to describe the particulate components of the high-temperature insulating composite (e.g., aerogel, expandable microspheres, reinforcing fibers, opacifying agents, and additional particulate components) as being non-covalently immobilized within the fibrillated microstructure of the polymer film. No separate binder is present to fix or otherwise bind the particulate components within the fibrillated film. Furthermore, it should be appreciated that in some embodiments, the particulate component is located throughout the thickness of the fibrillated polymer membrane of the high temperature insulating composite.

[0053] High temperature insulating composites can be molded into thin, flexible, compressible, and conformable shapes due at least in part to the strength of the fibrillated polymer matrix, thereby facilitating the ability to produce molded materials suitable for intended applications.

[0054] aerogel particles The terms "aerogel," "aerogels," and "aerogel particles" are used interchangeably herein. Aerogels are thermal insulators that significantly reduce convective and conductive heat transfer. Silica aerogel particles are particularly good conductive insulators. Aerogel particles are solid, hard, dry materials that are commercially available in powder form. A non-limiting example of a commercially available aerogel material is silica aerogel formed by a relatively low-cost process such as that described in U.S. Pat. No. 6,172,120 to Smith et al. Furthermore, the size of aerogel particles can be reduced to a desired dimension or grade by jet milling or other known size reduction techniques. Aerogel particles suitable for use in high temperature thermal insulation composites can have a size of about 1 μm to about 1 mm, about 1 μm to about 500 μm, about 1 μm to about 250 μm, about 1 μm to about 200 μm, about 1 μm to about 150 μm, about 1 μm to about 100 μm, about 1 μm to about 75 μm, about 1 μm to about 50 μm, about 1 μm to about 25 μm, about 1 μm to about 10 μm, or about 1 μm to about 5 μm. Further suitable aerogel particles have a size of about 0.1 μm to about 1 μm, about 0.2 μm to about 1 μm, about 0.3 μm to about 1 μm, about 0.4 μm to about 1 μm, about 0.5 μm to about 1 μm, about 0.6 μm to about 1 μm, about 0.7 μm to about 1 μm, about 0.8 μm to about 1 μm, or about 0.9 μm to about 1 μm. Aerogels having smaller particle sizes, such as 200 nm or less, 150 nm or less, 100 nm or less, or 50 nm or less, can also or alternatively be utilized in the high-temperature thermal insulation composites.

[0055] The amount of aerogel particles present in the high temperature insulating composite can be greater than 35 wt%, greater than 40 wt%, greater than 50 wt%, greater than 60 wt%, greater than 70 wt%, or greater than 80 wt%. In some embodiments, the amount of aerogel particles present in the high temperature insulating composite ranges from about 10 wt% to about 80 wt%, from about 15 wt% to about 80 wt%, from about 20 wt% to about 80 wt%, from about 25 wt% to about 80 wt%, from about 30 wt% to about 80 wt%, from about 35 wt% to about 70 wt%, from about 40 wt% to about 80%, from about 40 wt% to about 70 wt%, from about 40 wt% to about 65 wt%, from about 40 wt% to about 60 wt%, from about 45 wt% to about 60 wt%, or from about 45 wt% to about 55 wt%. In other embodiments, the aerogel particles may be present in the high temperature insulating composite in an amount of about 45 wt% to about 75 wt%, about 50 wt% to 70 wt%, or about 45 wt% to about 60 wt%.

[0056] The bulk density of aerogel particles is approximately 100 kg / m 3 Less than 75 kg / m 3 Less than 50 kg / m 3 Less than 25 kg / m 3 Less than or about 10 kg / m 3 In at least one embodiment, the aerogel particles can have a density of less than about 30 kg / m 3 ~about 50kg / m 3 It has a bulk density of

[0057] Aerogels suitable for use in high-temperature insulating composites include inorganic aerogels, organic aerogels, and mixtures thereof. Non-limiting examples of suitable inorganic aerogels include those formed from inorganic oxides of silicon (silicon dioxide), inorganic oxides of aluminum, inorganic oxides of titanium, inorganic oxides of zirconium, inorganic oxides of hafnium, inorganic oxides of yttrium, inorganic oxides of vanadium, and combinations thereof. In at least one embodiment, the high-temperature insulating composite comprises an inorganic aerogel, such as silica aerogel. Another example of a high-temperature insulating particle suitable for the high-temperature insulating composite is fumed silica.

[0058] Aerogels used in high-temperature thermal insulation composites can be hydrophilic or hydrophobic. In some embodiments, the aerogels are hydrophobic to partially hydrophobic and have a thermal conductivity of less than about 15 mW / mK. It should be understood that particle size reduction techniques, such as milling, can affect some of the exterior surface groups of hydrophobic aerogels, resulting in hydrophobic aerogel particles that may exhibit partial surface hydrophilicity (e.g., hydrophobic properties are retained within the aerogel particles). Partially hydrophobic aerogels may exhibit enhanced bonding with other compounds and may be useful in applications where such bonding is desirable.

[0059] opacifying agent In one embodiment, the high-temperature insulating composite includes at least one opacifying agent. The opacifying agent reduces radiative heat transfer and improves thermal performance. Non-limiting examples of opacifying agents suitable for use in the high-temperature insulating composite include, but are not limited to, carbon black, titanium dioxide, iron oxide, silicon carbide, molybdenum disilicide, manganese oxide, polydialkylsiloxanes having alkyl groups containing 1 to 4 carbon atoms, or any combination thereof. In one embodiment, the opacifying agent may be used in the form of a finely dispersed powder. In at least one embodiment, the amount of opacifying agent present in the high-temperature insulating composite is about 60 wt% or less. In some embodiments, the opacifying agent is present in an amount greater than about 10 wt%. In further embodiments, the amount of opacifying agent present in the high temperature insulating composite is from about 0.1 wt% to about 60 wt%, from about 0.5 wt% to about 60 wt%, from about 1 wt% to about 60 wt%, from about 5 wt% to about 60 wt%, from about 5 wt% to about 55 wt%, from about 10 wt% to about 60 wt%, from about 10 wt% to about 55 wt%, from about 10 wt% to about 50 wt%, from about 10 wt% to about 40 wt%, from about 10 wt% to about 30 wt%, from about 15 wt% to about 30 wt%, or from about 20 wt% to about 30 wt%. , about 15 wt% to about 50 wt%, about 15 wt% to about 45 wt%, about 15 wt% to about 40 wt%, about 15 wt% to about 35 wt%, about 20 wt% to about 40 wt%, about 25 wt% to about 35 wt%, or about 15 wt% to about 25 wt%. In some embodiments, the opacifying agent may not be included as a separate component in the high temperature insulating composite. In some examples, the opacifying agent may be present in an amount less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, or less than 1% as a component of the total amount of additional particles.

[0060] reinforced fiber In some embodiments, the high-temperature insulating composite also includes at least one reinforcing fiber. In one embodiment, the reinforcing fiber can be chopped fiber having a size of about 0.1 mm to about 25 mm, about 0.1 mm to about 19 mm, about 0.1 mm to about 15 mm, about 0.1 mm to about 13 mm, about 0.1 mm to about 10 mm, about 0.1 mm to about 7 mm, or about 0.1 mm to about 5 mm. Various reinforcing fibers can be used, including, but not limited to, carbon fiber, glass fiber, aluminoborosilicate fiber, or combinations thereof. In at least one embodiment, the reinforcing fiber is chopped glass fiber. The amount of reinforcing fiber present in the high-temperature insulating composite is about 25 wt% or less. In some embodiments, the reinforcing fibers are present in an amount of about 1 wt% to about 25 wt%, about 2 wt% to about 20 wt%, about 3 wt% to about 20 wt%, about 5 wt% to about 15 wt%, about 8 wt% to about 15 wt%, about 9 wt% to about 15 wt%, or about 10 wt% to about 15 wt%. In some embodiments, the reinforcing fibers are present in an amount of about 1 wt% to about 10 wt%, about 2 wt% to about 10 wt%, about 3 wt% to about 10 wt%, about 4 wt% to about 10 wt%, about 5 wt% to about 10 wt%, about 6 wt% to about 10 wt%, about 7 wt% to about 10 wt%, or about 8 wt% to about 10 wt%.

[0061] Expandable Microspheres The high temperature insulating composite can further include one or more expandable microspheres (e.g., Expancel®, commercially available from Nouryon Chemicals BV, The Netherlands). In one embodiment, the high temperature insulating composite includes up to about 20 wt% expandable polymer microspheres, such as EXPANCEL®. Expandable microspheres can generally be described as expandable thermoplastic microspheres that encapsulate an expanding gas. In some embodiments, the high temperature insulating composite includes the expandable microspheres in an amount of about 1 wt% to about 20 wt%, about 1 wt% to about 15 wt%, or about 1 wt% to about 10 wt%. In some embodiments, the expandable microspheres are present in the high temperature insulating composite in an amount of about 1 wt% to about 15 wt%, about 1 wt% to about 14 wt%, about 1 wt% to about 13 wt%, about 1 wt% to about 12 wt%, about 1 wt% to about 11 wt%, about 1 wt% to about 10 wt%, about 1 wt% to about 9 wt%, about 1 wt% to about 8 wt%, about 1 wt% to about 7 wt%, about 1 wt% to about 6 wt%, about 1 wt% to about 5 wt%, or about 1 wt% to about 3 wt%. In some embodiments, the expandable microspheres are present in the high temperature insulating composite in an amount of about 0.1 wt% to about 10 wt%, about 0.1 wt% to about 9 wt%, about 0.1 wt% to about 8 wt%, about 0.1 wt% to about 7 wt%, about 0.1 wt% to about 6 wt%, about 0.1 wt% to about 5 wt%, about 0.1 wt% to about 5 wt%, about 0.1 wt% to about 4 wt%, about 0.1 wt% to about 3 wt%, about 0.1 wt% to about 2 wt%, about 0.1 wt% to about 1 wt%, about 0.5 wt% to about 5 wt%, about 0.5 wt% to about 4 wt%, about 0.5 wt% to about 3 wt%, about 0.5 wt% to about 2 wt%, or about 0.5 wt% to about 1 wt%.

[0062] The use of expandable microspheres can reduce the density of the resulting high temperature insulating composite and articles containing the high temperature insulating composite. In one embodiment, the high temperature insulating composite has a density of about 0.01 g / cm 3 ~Approx. 0.40g / cm 3 , about 0.01g / cm 3 ~about 0.30g / cm 3 , about 0.01g / cm 3~Approx. 0.25g / cm 3 or about 0.05 g / cm 3 ~Approx. 0.25g / cm 3 The high-temperature insulating composite can have a density ranging from 0.01 to 0.01 mm. Additionally, the high-temperature insulating composite is compressible, meaning that its overall thickness can be reduced by applying pressure to it. High-temperature insulating composite embodiments including expandable microspheres exhibit greater compressibility at low to moderate compressive stress values ​​while maintaining compressive stiffness as the compressive stress increases to higher values. The compressibility of the high-temperature insulating composite can be adjusted by varying the amount of expandable microspheres. Furthermore, when placed within a container or volume of specific, fixed dimensions (e.g., a battery cell), the compressible high-temperature insulating composite can help accommodate gaps or spaces caused by individual dimensional variations. The high-temperature insulating composite can also maintain a desired compressive stress or torque for an individual cell, even as the cell's dimensions change due to temperature fluctuations and charge / discharge cycling.

[0063] Additional ingredients The high temperature insulating composite may further include one or more additional components such as, but not limited to, flame retardant materials, additional polymers, opacifying agents (as described above), intumescent materials, oxygen scavengers, dyes, plasticizers, and thickeners.

[0064] 1A, the aerogel particles, opacifying agent, reinforcing fibers, expandable microspheres, and / or additional components (hereinafter grouped as "particle components") are durably entangled within the microstructure of the fibrillated polymer matrix of the high temperature insulating composite, and the thermal conductivity of the high temperature insulating composite is 25 milliwatts per meter Kelvin (mW / mK) or less, 23 mW / mK or less, 21 mW / mK or less, 19 mW / mK or less, or 17 mW / mK or less at atmospheric conditions (298.15 K and 101.3 kPa). As used herein, the phrase "durably entangled" is intended to describe the particle components of the high temperature insulating composite (e.g., aerogel, expandable microspheres, reinforcing fibers, expandable microspheres, and / or opacifying agent and / or additional particle components) as being non-covalently immobilized within the microstructure of the fibrillated polymer film. No separate binder is present to secure the particulate component within the fibrillated membrane. Furthermore, it should be understood that the particulate component is distributed throughout the thickness of the fibrillated polymer membrane. The particulate component

[0230] is fairly evenly distributed throughout the microstructure of the fibrillated polymer membrane of the high temperature insulating composite

[0200] . The high temperature insulating composite

[0200] has a challenge side

[0210] , a protected side

[0220] , a height (H), and a length (L).

[0065] The high temperature insulating composite can be formed from a composite (e.g., one layer) as generally shown in Figure 1A, or optionally from a multi-layer stack high temperature insulating composite (e.g., multiple individual layers) as generally shown in Figure 1B. In a multi-layer stack high temperature insulating composite, each layer can have particles therein with different chemical compositions, different particle sizes, different particle size distributions, or different particle distributions. In one embodiment, opacifiers with different properties, such as composition, size, and / or shape, can be distributed in various layers throughout the thickness of the high temperature insulating composite, as described by Hu et al. (Radiative Characteristics of Opacifier Loaded Silica Aerogel Composites, 2013).

[0066] In the multilayer stack high temperature insulating composite shown in Figure 1B, for ease of illustration, only the opacifier is shown among the particle components present in the multilayer stack high temperature insulating composite. Figure 1B is a schematic cross-sectional view of one embodiment of a multilayer stack high temperature insulating composite having multiple layers. As shown, the multilayer stack high temperature insulating composite

[0240] has a height (H) and a length (L). The multilayer stack high temperature insulating composite

[0240] includes a challenge side

[0250] and a protected side

[0260] .

[0067] In the embodiment shown in FIG. 1B, the height (H) is divided into three layers: Layer A

[0270] , Layer B

[0280] , and Layer C

[0290] . In some embodiments, Layer A

[0270] , Layer B

[0280] , and Layer C

[0290] can contain the same type of opacifying agent, but with different size distributions. In other embodiments, Layer A

[0270] , Layer B

[0280] , and Layer C

[0290] can include different types of opacifying agents with different size distributions. As shown in FIG. 1B, Layer A

[0270] has a first opacifying agent

[0300] with a first size distribution, Layer B

[0280] has a first opacifying agent

[0300] with a second size distribution, and Layer C

[0290] has a second opacifying agent

[0310] with a first size distribution. The first opacifying agent

[0300] can be silicon carbide and the second opacifying agent

[0310] can be carbon black, although this is exemplary in nature and is not intended to limit the scope of the present disclosure. In some embodiments, the particle components themselves may be different in each layer, or may be different only in certain layers. In other embodiments, the particle components are the same in each layer, but each layer has a different size distribution. Thus, each layer of a multilayer stack high-temperature thermal insulation composite can include one or more particle components having different chemical compositions, different particle sizes, and / or different particle size distributions within each layer (or only within certain layers).

[0068] In forming the multi-layer stack high temperature insulating composite, each layer is formed separately as described below and then laminated or stacked together to obtain the desired orientation of the layers in the multi-layer stack high temperature insulating composite. The layers can be bonded together by any conventional method, such as laminating, adhesively bonding, or otherwise bonding, to form the multi-layer high temperature insulating composite.

[0069] Fibrillated Polymer Matrix When a high-temperature insulating composite is made using a fibrillizable polymer, the aerogel particles and other particulate filler components can be durably bonded (e.g., non-covalently and with little or no dust) to form thin, flexible form elements (e.g., films, sheets, and tubes) distributed within the fibrillated polymer matrix. It should be understood that no absorption process exists to introduce the aerogel particles and other particulate filler components into the fibrillated polymer matrix. Thus, the aerogel particles and particulate components within the high-temperature insulating composite are durably entangled within the fibrillated polymer matrix. Thin, flexible form elements are important for many applications where high-temperature events may occur, such as capacitors, heating elements, and high-energy batteries. Even when the fibrillated polymer matrix within the high-temperature insulating composite is completely volatilized, the remaining components provide a separate matrix that provides protection. This is because at least the particulate filler components are thermally more stable than the fibrillated polymer matrix. In at least one embodiment, the high temperature insulating composite has a thickness of about 5 mm or less, about 4 mm or less, about 3 mm or less, about 2 mm or less, or about 1 mm or less. In some embodiments, the high temperature insulating composite has a thickness of about 1 mm to about 5 mm, about 1 mm to about 4 mm, about 1 mm to about 3 mm, about 1 mm to about 2 mm, about 0.01 mm to about 5 mm, about 0.01 mm to about 4 mm, about 0.1 mm to about 3 mm, about 0.1 mm to about 2.5 mm, about 0.1 mm to about 2 mm, about 0.1 mm to about 1.5 mm, or about 0.1 mm to about 1 mm. In still other embodiments, the high temperature insulating composite has a thickness of 1 mm or less.

[0070] As used herein, the terms "fibrillating" and "fibrillizable" refer to the ability of a polymer to form a microstructure of nodes and fibrils or a microstructure comprising substantially only fibrils when subjected to sufficient shear. In some embodiments, the fibrillating polymer may be mixed by, for example, wet mixing, dispersion, or agglomeration. The time and temperature at which the shearing and / or mixing occurs will vary depending on the particle size, materials used, and amount of particles mixed, and are readily determined by one of ordinary skill in the art.

[0071] A variety of fibrillizable polymers can be used to obtain the high-temperature insulating composites of the present invention. Using a fibrillizable polymer as a binder in a high-temperature insulating composite provides both strength (and the ability to form thin materials), conformability, and compressibility while durably entangling the particulate components into a cohesive shape. It should be noted that aerogel, expandable microspheres, opacifiers, and reinforcing fibers, as well as additional components, are considered "particulate components" herein. Blending fibrillizable polymer particles with other particulate components in a high-temperature insulating composite (e.g., aerogel, opacifiers, reinforcing fibers, expandable microspheres, etc.) with sufficient shear during a blending / molding process results in a fibrillated polymer matrix (a microstructure of nodes interconnected by fibrils, or essentially only fibrils) in which the particulate material is durably entangled.

[0072] The decomposition temperature of the fibrillating polymer matrix varies depending on the nature of the polymer. In one embodiment, the fibrillating polymer matrix is ​​prepared from fibrillizable polymer particles of polyolefin, fluoropolymer, polyurethane, polyester, polyamide, polylactic acid, or any combination thereof. Non-limiting examples of fibrillizable polymers include, but are not limited to, polytetrafluoroethylene (PTFE) (Gore, U.S. Pat. No. 3,315,020; Gore, U.S. Pat. No. 3,953,566; Baille, U.S. Pat. No. 7,083,225), expanded polytetrafluoroethylene (ePTFE), ultra-high molecular weight polyethylene (UHMWPE) (Sbriglia, U.S. Pat. No. 10,577,468), polylactic acid (PLLA; Sbriglia, U.S. Pat. No. 9,732,184), copolymers of vinylidene fluoride and tetrafluoroethylene or trifluoroethylene (e.g., VDF-co-(TFE or TrFE) polymers, Sbriglia, U.S. Pat. No. 6,083,225). No. 10,266,670 to Sbriglia), poly(ethylene tetrafluoroethylene) (ETFE, U.S. Pat. No. 9,932,429 to Sbriglia), polyparaxylylene (PPX, U.S. Pat. Pub. No. 2016 / 0032069 to Sbriglia), and polytetrafluoroethylene (PTFE, U.S. Pat. No. 3,315,020 to Gore, U.S. Pat. No. 3,953,566 to Gore, and U.S. Pat. No. 7,083,225 to Baille). In one embodiment, the fibrillating polymer is a fibrillating PTFE made from non-melt-processible PTFE fine powder particles (i.e., the melt flow viscosity is too high for melt extrusion and high shear blending and / or pasting is required to form the fibrillating polymer matrix) (see, e.g., Expanded PTFE Applications Handbook - Technology, Manufacturing and Applications, Ebnesajjad, Sina, (1997), Elsevier, Cambridge, MA).

[0073] As used herein, the term "PTFE" refers to homopolymer PTFE and modified PTFE resins (e.g., having up to 5 wt%, up to 4 wt%, up to 3 wt%, up to 2 wt%, or up to 1 wt% of one or more ethylenic comonomers, including, but not limited to, perfluoroalkyl ethylenes (e.g., perfluorobutyl ethylene, U.S. Pat. No. 7,083,225 to Baille), hexafluoropropylene, perfluoroalkyl vinyl ethers (C1-C8 alkyl, e.g., perfluoromethyl vinyl ether, perfluoroethyl vinyl ether, perfluoropropyl vinyl ether, perfluorooctyl vinyl ether, etc.). PTFE is described, for example, in U.S. Pat. No. 5,708,044 to Branca, U.S. Pat. No. 6,541,589 to Baille, U.S. Pat. No. 7,531,611 to Sabol et al., U.S. Pat. No. 8,637,144 to Ford, and U.S. Pat. No. 8,637,144 to Xu). Also intended to be included are expanded modified PTFE and expanded copolymers of PTFE, such as those described in US Pat. No. 9,139,669 to Gill, et al.

[0074] Suitable fibrillating fluoropolymers may also include fibrillizable copolymers and terpolymers of tetrafluoroethylene (TFE) with comonomers such as vinylidene fluoride (VDF), vinylidene difluoride, hexafluoroisobutylene (HFIB), trifluoroethylene (TrFE), chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), fluorodioxoles or fluorodioxalanes (e.g., U.S. Pat. No. 9,040,646 to Ford) and ethylene (e.g., ethylene tetrafluoroethylene (ETFE, U.S. Pat. No. 9,932,429, supra). All of the above-identified polymers will at least partially or completely volatilize (decompose) when exposed to a high temperature event of at least 800°C.

[0075] In some embodiments, the fibrillated polymer matrix is ​​a polytetrafluoroethylene (PTFE) matrix or an expanded polytetrafluoroethylene (ePTFE) matrix having a node and fibril microstructure, or a microstructure containing substantially only fibrils. The fibrils of the PTFE particles interconnect with other PTFE fibrils and / or nodes to form a net within and around the particle component, effectively immobilizing the particle component within the polymer matrix.

[0076] The amount of fibrillating polymer present in the high temperature insulating composite is about 60 wt% or less, about 50 wt% or less, about 40 wt% or less, about 30 wt% or less, about 20 wt% or less, or about 10 wt% or less. The fibrillating polymer can be present in the high temperature insulating composite in an amount of about 1 wt% to about 60 wt%, about 1 wt% to about 50 wt%, about 1 wt% to about 40 wt%, about 1 wt% to about 30 wt%, about 1 wt% to about 25 wt%, about 1 wt% to about 20%, about 1 wt% to about 15 wt%, about 1 wt% to about 15 wt%, or about 1 wt% to about 10 wt%. In other embodiments, the amount of fibrillating polymer ranges from about 5 wt% to about 30 wt%, from about 10 wt% to about 25 wt%, from about 1 wt% to about 20 wt%, from about 1 wt% to about 15 wt%, from about 1 wt% to about 10 wt%, or from about 1 wt% to about 5 wt%.

[0077] In some embodiments, the porous fibrillating polymer matrix may be formed by dry blending fibrillizable polymer particles with other particle components in a manner generally taught in U.S. Publication No. 2010 / 0119699 to Zhong et al., U.S. Patent No. 7,118,801 to Ristic-Lehmann et al., U.S. Patent No. 5,849,235 to Sassa et al., U.S. Patent No. 6,218,000 to Rudolf et al., or U.S. Patent No. 4,985,296 to Mortimer, Jr.

[0078] In one embodiment, the agglomerates can be prepared using the general methodology described in U.S. Patent No. 7,118,801 to Ristic-Lehmann et al. A typical method for preparing the agglomerates involves mixing an aqueous dispersion of particulate component particles (aerogel particles, opacifying agent, reinforcing fibers, and / or additional particulate components) with a dispersion of fibrillizable polymer particles, followed by agglomeration of the mixture by stirring or adding a flocculating agent. The co-agglomeration of the polymer particles in the presence of the other particulate components results in an intimate blend of the fibrillizable polymer particles and the other particulate component particles (i.e., the insulating material). This insulating material is drained and dried in a convection oven at approximately 433 K. Depending on the type of wetting agent used, the dried insulating material can be in the form of a loosely bound powder or a soft cake, which can then be cooled and crushed to obtain the insulating material in powder form. The powdered insulation material can then be blended with a suitable hydrocarbon lubricant (e.g., an isoparaffinic lubricant (e.g., ISOPAR K® available from ExxonMobil Corporation, Houston, Texas)) for a subsequent mechanical processing step to induce fibrillation and the formation of a cohesive matrix into a desired form factor, such as a tape, sheet, or putty. The mechanical processing step can include one or more of high shear mixing, pressing, calendering, and combinations thereof, to form a high temperature insulation composite having a fibrillated polymer matrix. At least one drying step is included to remove the hydrocarbon lubricant.

[0079] The high temperature insulating composite can be formed into a relatively thin form factor (e.g., a sheet). The thin form factor of the high temperature insulating composite makes it attractive for use in electronic devices and / or batteries where undesirable high temperature thermal events may occur. In one embodiment, the high temperature insulating composite is formed into a molded putty, tube, tape, or sheet having an average thickness (or tube wall thickness, in the case of a tube) of less than about 5 mm, about 4 mm or less, about 3 mm or less, about 2 mm or less, or about 1 mm or less.

[0080] Articles containing high-temperature insulating composites In one embodiment, a thermal insulating article includes a first component capable of generating a high temperature event (i.e., a first temperature), a second component protected from exposure to the first temperature caused by the high temperature event, and a high temperature insulating composite. The high temperature insulating component is disposed between the first component and the second component. The high temperature insulating component can be in the form of a tube, sheet, or film. The first side of the high temperature insulating component can be oriented toward the first component, and the second side of the high temperature insulating component can be oriented toward the second component. In some embodiments, the high temperature insulating composite has a thermal conductivity of 25 milliwatts per meter Kelvin (Mw / mK) or less at atmospheric conditions (298.15 K and 101.3 kPa).

[0081] The thermal insulation article can also include one or more support materials in the form of a support layer on one or more sides of the high-temperature insulating composite. In one embodiment, the support layer is a polymer layer, a woven layer, a knitted layer, a nonwoven layer, or any combination thereof. The polymer layer can be a non-porous layer, a porous layer, a microporous layer, or any combination thereof. Non-limiting additional support layers include fluoropolymer membranes (e.g., polytetrafluoroethylene membranes), expanded fluoropolymer membranes (e.g., expanded polytetrafluoroethylene membranes), polyolefin membranes (e.g., polyethylene membranes), metal membranes, electrical insulators, adhesive layers, or any combination thereof. Support layers can be included in the thermal insulation article by laminating, adhering, or otherwise bonding one or more support layers to the high-temperature insulating composite. For example, the high-temperature insulating composite can be in the form of a sheet or film having a first side and a second side, and the thickness is less than the width and / or length. The one or more support layers can be adhered to the first side, the second side, or both the first and second sides of the high temperature insulating composite.

[0082] One or more support layers can be adhered to the high-temperature insulating composite using adhesives, welding, calendaring, coating, or any combination thereof. In some embodiments, the insulating article can include multiple layers. For example, the high-temperature insulating composite can have a layer of expanded PTFE adhered to one or both sides, resulting in a high-temperature insulating composite having a two-layer or three-layer structure. One or more textile layers, such as woven fabrics, knitted fabrics, nonwoven fabrics, or any combination thereof, can be adhered to the high-temperature insulating composite. As is well known in the art, adhesives can be applied to the high-temperature insulating composite, the textile, or both, in a continuous or discontinuous manner.

[0083] The textile layer can be a woven fabric, a knitted fabric, a nonwoven fabric, or any combination thereof. In some embodiments, the woven, knitted, or nonwoven textile can be a flame-resistant woven fabric, a flame-resistant knitted fabric, or a flame-resistant nonwoven textile. Suitable textile layers are well known in the art and can include, for example, elastic and non-elastic textiles such as LYCRA®, polyurethane, polyester, polyamide, acrylic, cotton, wool, silk, linen, rayon, flax, jute, flame-resistant textiles such as NOMEX® aramid (available from DuPont, Wilmington, Delaware), aramid, flame-resistant cotton, polybenzimidazole, poly-p-phenylene-2,6-benzobisoxazole, flame-resistant rayon, modacrylic, modacrylic blends, polyamine, carbon, glass fiber, or combinations thereof.

[0084] Lithium-ion battery In some embodiments, the high-temperature insulating composite is used as an insulating and protective barrier layer in high-energy batteries, such as multi-cell lithium-ion batteries. In one aspect, the insulating and protective barrier is used to at least partially or completely encapsulate or isolate one or more cells within the battery or the battery itself. In another embodiment, the battery cells are completely encapsulated by the high-temperature insulating composite. The high-temperature insulating composite can also be used in module or pack insulation to prevent the propagation of thermal energy or the harmful effects of propagation that can occur when thermal energy propagates to the other side of a high-temperature insulating component.

[0085] Other embodiments in which the high temperature insulating composites can be utilized include, but are not limited to, lithium cells used in the electrification of aircraft and drones, lithium cells used in residential energy storage (e.g., solar or wind energy storage), lithium cells used in energy backup systems for buildings and critical infrastructure, cells used in computer power backup systems or uninterruptible power systems (UPS), cells used in electric marine vehicles, drones and unmanned aerial vehicles (UAVs), cells used in personal vehicles (e.g., scooters), and cells used in emergency medical backup systems.

[0086] The disclosure of this application has been described above both generically and with respect to specific embodiments. It will be apparent to those skilled in the art that various modifications and variations of the disclosure can be made without departing from the spirit or scope of the disclosure, as defined in the appended claims.

[0087] Test Method Although particular methods and apparatus are described below, it should be understood that any method or apparatus deemed suitable by one of ordinary skill in the art may alternatively be utilized.

[0088] Density measurement The density of the composite insulation was calculated using the formula density = mass / volume. The mass of a 1.5-inch diameter punch was determined using a Sartorius Entris 224-1S analytical balance. Sample thickness was measured by placing the sample between two glass slides of known thickness and using a Mitutoyo Lightmatic VI-50 contact gauge with a probe force of 0.2 N. Three samples were tested, recorded, and then averaged to determine the average density.

[0089] Tensile strength The tensile strength of the films was measured using an INSTRON® 5565 tensile tester equipped with flat grips and a 0.445 kN load cell. The gauge length was 6.35 cm, and the crosshead speed was 50.8 cm / min (strain rate = 13.3% / sec). To ensure comparable results, the laboratory temperature was maintained between 68°F (20°C) and 72°F (22.2°C). If the sample failed at the grip interface, the data was discarded.

[0090] For longitudinal (lengthwise) tensile strength measurements, the larger dimension of the sample was oriented in the machine direction, or "down-web" direction. For transverse tensile strength measurements, the larger dimension of the sample was oriented perpendicular to the machine direction, also known as the "cross-web" direction. The sample thickness was then measured using a Mitutoyo 547-400 absolute snap gauge. The samples were then individually tested on a tensile tester. Three different sections of each sample were measured. The average of the three maximum load (i.e., peak force) measurements was used.

[0091] The longitudinal and transverse tensile strengths were calculated using the following formulas:

number

[0092] The average of three cross-web measurements was recorded as the longitudinal and transverse tensile strength.

[0093] Thickness The thickness of the samples was measured using the integrated thickness measurement of a thermal conductivity measuring instrument (Laser Comp Model Fox 314 Laser Comp, Saugus, MA). The results of one measurement were recorded.

[0094] Room temperature thermal conductivity Thermal conductivity was also measured without compressing the samples. Samples were measured using a Laser Comp Model Fox 314 Thermal Conductivity Analyzer (Laser Comp, Saugus, MA). A single measurement was recorded. Two 8" x 8" (20.3 cm x 20.3 cm) samples were stacked and measured at a delta-T of 20°C with the hot and cold plates at 35°C and 15°C, respectively.

[0095] Compression set test Compressive stress-strain properties and compression set behavior were determined using ASTM D395-18, except the samples were 1 mm thick and 3.08 cm in diameter (i.e., an Instron 5565 test frame using a 1 kN load cell, a 5.08 cm diameter upper compression platen, a 12.7 cm diameter lower self-aligning spherically seated compression plate, an LVDT deflection sensor fixed to the upper compression platen and in contact with the lower compression plate, and a 3.08 cm diameter high-temperature insulating composite). Compression set behavior was determined at 50% compression displacement and held for 30 minutes and calculated using the following equation:

number

[0096] For compressive stress-strain behavior, compression was then initiated at a displacement rate of 0.5 mm / min until a displacement of 50% of the measured thickness was achieved. Once 50% of the original thickness was reached, the plate displacement was fixed for 30 minutes to 24 hours, after which the displacement plate was released. Figure 4 shows a graphical representation of compressive engineering stress versus thickness-normalized compressive deflection.

number

[0097] Heat-transmitted protective barrier assay The following assay was used to measure the thermal barrier performance of a high temperature insulating composite when exposed to a heated mass having a temperature sufficient to partially or completely volatilize (e.g., decompose) the fibrillated polymer within the high temperature insulating composite. A thin sheet (approximately 1 mm) of the high temperature insulating composite was compressed into contact with a stainless steel block ("thermal reservoir") at approximately 800°C, measuring 5.5 inches (approximately 14.0 cm) high, 3.5 inches (approximately 7.6 cm) wide, and 0.375 inches (approximately 0.95 cm) thick. The composite had a density of 7999.4 kg / m 3 , volumetric heat capacity of 617.6 J / kgK, and calculated sensible energy of 435 kJ. The side of the test material placed in contact with the heated mass is referred to herein as the "challenge side." The maximum temperature observed after contact on the opposite side of the test material (also referred to herein as the "protected side") was recorded for times ranging from 10 to 60 minutes. Thin sheets (approximately 1 mm thick) of high temperature insulating composite capable of limiting the maximum observed temperature to 215°C or less were considered suitable for use as high temperature insulating composites.

[0098] One side (the "challenge side") of a thin rectangular sheet (approximately 1 mm thick) of test material was placed in compression against a rectangular stainless steel block (referred to herein as the "heat store") heated to a target temperature of approximately 800 °C. To ensure symmetrical heat dissipation, two identical samples were placed on either side of the rectangular heat store. Type K thermocouples were used to measure the temperature of the heat store and the opposite side of each test sample. The average temperature of the opposite side of each test sample was continuously recorded over a period of time (10 to 60 minutes) after contact with the heat store, and the maximum average temperature observed during the contact period was recorded.

[0099] Referring to Figures 2 and 3 (Figure 3 is a side view of elements within the contact compression zone

[0113] during a test assay), a test system including a high temperature furnace

[0101] configured with an opening

[0102] for receiving a rectangular 304 stainless steel block ("heat reservoir")

[0103] measuring 5.5 inches x 3.5 inches x 0.375 inches (approximately 14.0 cm x 7.6 cm x 0.95 cm, respectively).

[0100] The total mass of the heat storage was 905 grams.

[0101] The heat store was heated to a temperature of approximately 800°C in the furnace. The volume, material properties, volumetric heat capacity, and thermal conductivity of the heat store were selected to achieve a specific sensible energy output representative of the energy released by the failure of a lithium-ion battery cell. The temperature of the heat store was measured using a Type K thermocouple

[0104] (bonded to the heat store

[0103] using a thermally stable, conductive ceramic epoxy). Using a pneumatically controlled transfer system

[0105] , the heat store

[0103] at approximately 800°C was rapidly removed from the furnace

[0101] and placed in the contact compression zone

[0113] .

[0100] The test sample

[0109] was glued to the surface of a 1 mm thick, 4 inch x 6 inch (approximately 10.16 cm x 15.25 cm each) aluminum support sheet

[0108] . The aluminum sheet

[0108] included a small 90° flange to help hold the test sample supported on the compression plate

[0107] . A Type K thermocouple

[0110] was placed in a 0.5 mm deep groove on the face of the thin aluminum support sheet

[0108] opposite the test sample

[0109] and embedded with thermally stable, conductive ceramic epoxy, allowing the temperature of the opposite side of the test sample (i.e., the side not in direct contact with the thermal mass) to be measured while maintaining compression planarity.

[0101] A contact compression zone

[0113] with two flat compression plates

[0107] was used to compress the thermal mass

[0103] against one side of each test sample

[0109] . The plates

[0107] consisted of a machined stainless steel backer plate attached to a MACOR® machinable glass ceramic front plate (Corning Inc., Corning, NY). A thin aluminum sheet

[0108] containing the supported test sample

[0109] was placed on the compression plate

[0107] . The compression plate

[0107] was attached to a pneumatically controlled compression system

[0112] , which was used to bring the supported test sample into contact with the thermal mass

[0103] .

[0102] To begin the test, the approximately 800°C thermal mass was rapidly removed from the furnace

[0101] and placed between the two supported test samples. Using a compression system

[0112] , the compression plates (along with the supported test samples) were rapidly moved together

[0111] , bringing the test samples into compressive contact (at a pressure of approximately 42,300 Pa) against the thermal mass. Figure 3 is a side view showing the orientation of the elements within the contact compression zone

[0113] at the start of the test (time 0). Type K thermocouples

[0110] recorded the temperature on the opposite side of each test sample over time. The temperatures from the thermal mass and the thin aluminum support sheet

[0109] were recorded over a specified time period (10 to 60 minutes). The maximum average temperature observed during the specified contact period was recorded. Figure 4 is a graph showing a representative plot of the thermal mass temperature versus the temperature measured on the opposite side of the composite insulation sample 45 minutes after contact. [Example]

[0103] example Example 1 High-Temperature Insulating Composites The composite consisted of fibrillizable homopolymer polytetrafluoroethylene (PTFE) fine powder particles (44 wt%), 40 wt% aerogel particles (Cabot ENOVA™ silica aerogel, Cabot Corporation, Boston, MA), 8 wt% silicon carbide particles (opacifying agent) (F1200 Silicon Carbide, Washington Mills North Grafton, Inc., North Grafton, MA), and 8 wt% chopped glass fibers (#30 E-Glass, cut length 1 / 4 inch (6.4 mm), fiber diameter 13 microns (Fibre Glast Developments, Brookville, OH). Corp.) was blended with a mineral spirits lubricant. The blend was then extruded and dried to form a high-temperature insulating composite in the form of a sheet, as generally taught in U.S. Patent No. 7,868,083 to Ristic-Lehmann et al. The high-temperature sheet was approximately 1 mm thick and contained fibrillizable PTFE particles, aerogel particles, and silicon carbide particles durably entangled and immobilized within a fibrillated PTFE matrix (Sample 14, Table 1).

[0104] Additional high-temperature insulating composite samples were prepared using the same process, except for varying the amount of one or more of the aerogel particles, PTFE micropowder particles, chopped glass fiber, and opacifying agent in the sample (Table 1). All high-temperature insulating composite samples were tested using the heat-transfer protective barrier assay described above. The maximum temperature observed for each sample was measured and recorded as an average of four to six measurements. Table 1 provides a compositional breakdown of the various test samples, including thickness, density, and their respective performance as high-temperature insulating composites (i.e., average maximum temperature observed). It should be understood that all mass percentages are reported relative to the total mass of the final high-temperature insulating composite. [Table 1]

[0105] Example 2 High-temperature insulation composites were prepared using the process described in Example 1, except that expandable polymer microspheres (EXPANCEL® 951 DU 120, Nouryon Chemicals BV, The Netherlands) were added in the range of 1 wt% to 10 wt%, based on the total mass of the dried high-temperature insulation composite. After drying to remove the lubricant, the resulting high-temperature insulation composite was subjected to a temperature of 190°C for at least 30 minutes to increase the volume of the expandable polymer microspheres, resulting in an increase in the high-temperature insulation composite in the x, y, and z dimensions. High-temperature insulation composite samples containing expandable polymer microspheres were performance tested using the heat-transfer protective barrier assay described above.

[0106] The compressive properties of high-temperature insulating composite samples containing expandable microspheres were determined. The stress-strain behavior was evaluated using ASTM D395-18, except that the samples were 1 mm thick and 3.08 cm in diameter (i.e., Instron 5565 testing using the following: a 1 kN load cell frame, a 5.08 cm diameter upper compression platen, a 12.7 cm diameter bottom self-adjusting spherically seated compression plate, an LVDT deflection sensor fixed to the upper compression platen and in contact with the bottom compression plate, and a 3.08 cm diameter high-temperature insulating composite). The compressive strain of each high-temperature insulating composite sample was then calculated as a function of the force applied to each high-temperature insulating composite sample. Additionally, the compression set of the high-temperature insulating composites was measured according to the modified ASTM D395-18 method described in detail above. Figure 5 is a graph showing the thickness-normalized compressive deflection vs. compressive stress data for Samples 1-4 of Example 2. These samples demonstrate the ability to tailor the compressive behavior of high-temperature insulating composites, achieving a wide range of compressive deflection behavior at a constant compressive stress. Figure 6 shows the insulation thickness vs. compressive stress data for Samples 1-3 in Example 2. These samples demonstrate the ability to tailor the thickness of low-compressive stress insulating materials containing various amounts of expandable microspheres while maintaining a mechanically stiffened thickness as the compressive stress increases. This demonstrates the ability to assist in accommodating gaps and spaces resulting from variations in the individual dimensions of battery cells under low compressive stresses, while providing known insulation thickness under high compressive stresses relevant to lithium-ion battery charging cycle and life scenarios.

[0107] The composition breakdown, compression data and thermal performance of the various test samples are provided in Table 2. [Table 2]

[0108] The invention of this application has been described above both generically and with reference to specific embodiments. It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments without departing from the scope of the present disclosure. Therefore, it is intended that the embodiments cover the modifications and variations of the present invention provided they come within the scope of the appended claims and their equivalents. (Aspect) (Aspect 1) 50 wt% or less of a fibrillated polymer matrix; More than 40 wt% aerogel particles, and a total of more than 10 wt% of additional particulate components selected from one or more opacifying agents, one or more reinforcing fibers, one or more expandable microspheres, and any combination thereof; 1. A high temperature insulating composite comprising: The mass percentages are based on the total mass of the final high temperature insulating composite; A high temperature insulating composite, wherein the aerogel particles and the additional particulate component are durably entangled within a fibrillated polymer matrix. (Aspect 2) 10. The thermal insulation composite of embodiment 1 in the form of a tube, tape, or sheet having a thickness or tube wall thickness of 5 mm or less. (Aspect 3) 3. The thermal insulating composite of claim 1 or claim 2, wherein the fibrillated polymer matrix comprises a polyolefin, ultra-high molecular weight polyethylene, a fluoropolymer, polytetrafluoroethylene, expanded polytetrafluoroethylene, a polyurethane, a polyester, a polyamide, or any combination thereof. (Aspect 4) 4. The thermal insulating composite of any one of aspects 1 to 3, wherein the polymer is expanded polytetrafluoroethylene (ePTFE), expanded ultra-high molecular weight polyethylene (ePE), or a combination thereof. (Aspect 5) 5. The thermal insulating composite of any one of embodiments 1-4, wherein the total of the additional particulate components comprises less than 10% of one or more opacifying agents. (Aspect 6) 6. The thermal insulating composite of any one of embodiments 1-5, wherein the additional component comprises at least 2 wt. % of one or more reinforcing fibers. (Aspect 7) 7. The thermal insulating composite of any one of the preceding embodiments, wherein the additional particulate component comprises up to 30 wt. % expandable microspheres. (Aspect 8) 8. The thermal insulation composite of any one of claims 1 to 7, wherein the opacifying agent is selected from carbon black, titanium dioxide, aluminum oxide, zirconium dioxide, iron oxide, silicon carbide, molybdenum disilicide, manganese oxide, polydialkylsiloxane wherein the alkyl group contains 1 to 7 carbon atoms, or any combination thereof. (Aspect 9) 9. The thermal insulating composite of any one of aspects 1 to 8, wherein the one or more reinforcing fibers comprise carbon fibers, glass fibers, aluminoborosilicate fibers, or a combination thereof. (Aspect 10) less than 50 wt% of a fibrillated polymer matrix; less than 80 wt% aerogel particles; greater than 10 wt % of at least one opacifying agent; Up to 25 wt% reinforcing fibers, and less than 20 wt% expandable microspheres; 1. A high temperature insulating composite comprising: The mass percent is based on the total mass of the finished high temperature insulating composite article; A high temperature insulating composite, wherein the aerogel particles and the additional particulate component are durably entangled within a fibrillated polymer matrix. (Aspect 11) 11. The thermal insulation composite of embodiment 10, in the form of a tube, tape, or sheet having a thickness or tube wall thickness of 5 mm or less. (Aspect 12)

[0023] 12. The thermal insulating composite of claim 10 or 11, wherein the fibrillated polymer matrix comprises a polyolefin, ultra-high molecular weight polyethylene, a fluoropolymer, polytetrafluoroethylene, expanded polytetrafluoroethylene, a polyurethane, a polyester, a polyamide, or any combination thereof. (Aspect 13) 13. The thermal insulating composite of any one of aspects 10 to 12, wherein the polymer is expanded polytetrafluoroethylene (ePTFE), expanded ultra-high molecular weight polyethylene (ePE), or a combination thereof. (Aspect 14) 14. The thermal insulating composite of any one of embodiments 10-13, wherein the additional component comprises at least 2 wt % of one or more reinforcing fibers. (Aspect 15) 15. The thermal insulating composite of any one of embodiments 10-14, wherein the additional particulate component comprises up to 30 wt % expandable microspheres. (Aspect 16) 16. The thermal insulation composite of any one of claims 10 to 15, wherein the opacifying agent is selected from carbon black, titanium dioxide, aluminum oxide, zirconium dioxide, iron oxide, silicon carbide, molybdenum disilicide, manganese oxide, polydialkylsiloxane wherein the alkyl group contains 1 to 4 carbon atoms, or any combination thereof. (Aspect 17) 17. The thermal insulating composite of any one of aspects 10 to 16, wherein the one or more reinforcing fibers comprise carbon fibers, glass fibers, aluminoborosilicate fibers, or a combination thereof. (Aspect 18) 2. An article comprising the high temperature insulating composite of embodiment 1. (Aspect 19) 11. An article comprising the high temperature insulating composite of embodiment 10. (Aspect 20) 10. Use of the high temperature insulating composite of any one of embodiments 1 to 9 to prevent heat propagation in a lithium ion battery. (Aspect 21) 18. Use of the high temperature insulating composite of any one of embodiments 10 to 17 to prevent heat propagation in a lithium ion battery. (Aspect 22) a first component capable of generating a high temperature event having a first temperature; a second component protected from exposure to the first temperature; and a high temperature insulating composite positioned between a first element and a second element, the high temperature insulating composite having a first side facing the first component and an opposite side facing the second component; An article comprising: The high temperature insulating composite comprises: Approximately 40 wt% or more aerogel particles, about 60 wt% or less of a fibrillated polymer matrix; and 1 wt % to 45 wt % of one or more additional particulate components selected from one or more opacifying agents, one or more reinforcing fibers, one or more expandable microspheres, and any combination thereof; wherein the mass percent is based on the total mass percent of the final high temperature insulating composite; The article, wherein the aerogel particles and the additional particulate component are durably entangled within the fibrillated polymer matrix. (Aspect 23) providing an approximately 1 mm thick sheet of high temperature insulating composite material having a first side and a second side; The first side of the sheet of high temperature insulating composite is placed on a sheet of a material having a mass of about 905 g and a contact surface area of ​​about 106.4 cm 2 (14cm x 7.6cm), compressively contacting a heated stainless steel block having a temperature of about 800°C under a pressure of about 42.3kPa for 30 minutes; and measuring the temperature on the second side during the compression contact step for 30 minutes; 1. A heat spread test assay comprising: An adequate heat spread barrier is defined by a maximum measured temperature of less than 215°C, Heat Spread Test Assay. (Aspect 24) 1. A multi-layer high temperature insulating composite comprising a first layer and a second layer, The first layer and the second layer each comprise: The total wt% should equal 100 wt%. Approximately 40 wt% or more aerogel particles, about 60 wt% or less of a fibrillated polymer matrix; and 1 wt % to 45 wt % of one or more additional particulate components selected from one or more opacifying agents, one or more reinforcing fibers, one or more expandable microspheres, and any combination thereof; Including, the one or more additional particulate components vary in one or more of chemical composition, particle size, and particle size distribution across the first thickness of the first layer; and The one or more additional particulate components vary in one or more of chemical composition, particle size, and particle size distribution across the second thickness of the second layer. (Aspect 25) 25. The composite of embodiment 24, comprising a third layer, the third layer comprising one or more additional particulate components varying in one or more of chemical composition, particle size, and particle size distribution across the thickness of the third layer. (Aspect 26) 26. The composite of embodiment 25, wherein the one or more additional components are opacifying agents, the first layer comprising an opacifying agent having a first particle size distribution therein, the second layer comprising an opacifying agent having a second particle size distribution therein, and the third layer comprising an opacifying agent having a third particle size distribution therein.

Claims

1. A fibrillated polymer matrix comprising at least 1 wt% and at most 50 wt% of a fibrillated polymer matrix; More than 40 wt % and less than or equal to 80 wt % aerogel particles; and a total of more than 10 wt % and up to 60 wt % of additional particulate components selected from one or more opacifying agents, one or more reinforcing fibers, one or more expandable microspheres, and any combination thereof; Including, 1. A high temperature insulating composite, wherein the total amount of the fibrillated polymer matrix, the aerogel particles, and the additional particle component is 100 wt %, The mass percentages are based on the total mass of the final high temperature insulating composite; the aerogel particles and the additional particle component are durably entangled within a fibrillated polymer matrix; 10. A high temperature thermal insulation composite, wherein the one or more opacifying agents are selected from carbon black, titanium dioxide, aluminum oxide, zirconium dioxide, iron oxide, silicon carbide, molybdenum disilicide, manganese oxide, polydialkylsiloxane wherein the alkyl group contains 1 to 7 carbon atoms, or any combination thereof.

2. 10. The insulating composite of claim 1 in the form of a tube, tape or sheet having a thickness or tube wall thickness of 5 mm or less.

3. 3. The thermal insulating composite of claim 1 or claim 2, wherein the fibrillated polymer matrix comprises a polyolefin, ultra-high molecular weight polyethylene, a fluoropolymer, polytetrafluoroethylene, expanded polytetrafluoroethylene, a polyurethane, a polyester, a polyamide, or any combination thereof.

4. The thermal insulating composite of any one of claims 1 to 2, wherein the fibrillated polymer matrix is ​​expanded polytetrafluoroethylene (ePTFE), expanded ultra-high molecular weight polyethylene (ePE), or a combination thereof.

5. The thermal insulating composite of any one of claims 1 to 2, wherein the total of said additional particulate components comprises less than 10% of one or more opacifying agents.

6. The thermal insulating composite of any one of claims 1 to 2, wherein the additional component comprises at least 2 wt% of one or more reinforcing fibers.

7. The thermal insulating composite of any one of claims 1 to 2, wherein the additional particulate component comprises up to 30 wt% expandable microspheres.

8. The thermal insulating composite of any one of claims 1 to 2, wherein the one or more reinforcing fibers comprise carbon fibers, glass fibers, aluminoborosilicate fibers, or combinations thereof.

9. A fibrillated polymer matrix comprising greater than or equal to 1 wt% and less than 50 wt%. 10 wt% or more and less than 80 wt% aerogel particles; greater than 10 wt % and less than or equal to 60 wt % of at least one opacifying agent; 1 wt% or more and 25 wt% or less of reinforcing fibers, and 1 wt% or more and less than 20 wt% expandable microspheres; Including, 1. A high temperature thermal insulation composite, wherein the total amount of the fibrillated polymer matrix, the aerogel particles, the opacifying agent, the reinforcing fibers, and the expandable microspheres is 100 wt %, The mass percent is based on the total mass of the finished high temperature insulating composite article; the aerogel particles, the at least one opacifying agent, the reinforcing fibers, and the expandable microspheres are durably entangled within a fibrillated polymer matrix; 1. A high temperature thermal insulation composite, wherein the at least one opacifying agent is selected from carbon black, titanium dioxide, aluminum oxide, zirconium dioxide, iron oxide, silicon carbide, molybdenum disilicide, manganese oxide, polydialkylsiloxane wherein the alkyl group contains 1 to 4 carbon atoms, or any combination thereof.

10. 10. The insulating composite of claim 9 in the form of a tube, tape or sheet having a thickness or tube wall thickness of 5 mm or less.

11. 11. The thermal insulating composite of claim 9 or claim 10, wherein the fibrillated polymer matrix comprises a polyolefin, ultra-high molecular weight polyethylene, a fluoropolymer, polytetrafluoroethylene, expanded polytetrafluoroethylene, a polyurethane, a polyester, a polyamide, or any combination thereof.

12. The thermal insulating composite of any one of claims 9 to 10, wherein the fibrillated polymer matrix is ​​expanded polytetrafluoroethylene (ePTFE), expanded ultra-high molecular weight polyethylene (ePE), or a combination thereof.

13. The thermal insulation composite of any one of claims 9-10, wherein the high temperature insulating composite article comprises at least 2 wt% and up to 25 wt% of one or more reinforcing fibers. 。

14. The thermal insulating composite of any one of claims 9 to 10, wherein the reinforcing fibers comprise carbon fibers, glass fibers, aluminoborosilicate fibers, or combinations thereof.

15. An article comprising the high temperature insulating composite of claim 1.

16. 10. An article comprising the high temperature insulating composite of claim 9.

17. Use of the high temperature insulating composite material according to any one of claims 1 to 2 for preventing heat propagation in a lithium ion battery.

18. Use of the high temperature insulating composite material according to any one of claims 9 to 10 for preventing heat propagation in a lithium ion battery.

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