Laminated structure of aerogel polysiloxane layers

Abstract

The article includes a laminate material having an aerogel layer and a polysiloxane layer that is separate from the aerogel layer and in contact with the aerogel layer either directly or through an adhesive that is in direct contact with both the aerogel layer and the polysiloxane layer, the polysiloxane layer comprising polysiloxane and greater than 5 weight percent and less than or equal to 95 weight percent of a flame retardant additive, based on the weight of the polysiloxane layer, dispersed throughout the polysiloxane layer, selected from the group consisting of metal hydroxides, mixed metal hydroxides, hydrated metal salts, and any combination thereof.

Description

Technical Field

[0001] The present invention relates to a laminated article including an aerogel layer and a polysiloxane layer.

[0002] Introduction Electric vehicle (EV) technology is becoming increasingly popular. EV technology uses a battery pack to store energy and supply power to the vehicle. The energy demand of the vehicle is increasing, especially as the desire and demand for EVs that can travel longer distances while charging the battery pack grow. Uncontrolled release of the energy of a charged battery pack for EVs can lead to a major disaster due to huge heat release. Therefore, it is desirable to design a battery pack having protection against uncontrolled release of energy from the battery pack.

[0003] A battery pack for an EV typically includes a plurality of battery cells that are electrically connected to each other and assembled to directly form a battery pack or form modules, and then a plurality of modules are stacked to form a battery pack. An EV can contain up to thousands of battery cells. The battery cells are typically grouped into modules, and the modules are grouped together to form a battery pack. Failure of a single cell can release enough energy to heat adjacent cells, resulting in failure of those adjacent cells and release of more energy, thereby causing failure of more adjacent cells, etc., leading to uncontrolled release of energy within the battery pack. Therefore, it is desirable to identify a barrier material that can exist between the cells and modules of a battery pack and that can insulate adjacent cells from heat energy release when a cell fails. An ideal material is fire-resistant when exposed to temperatures exceeding 650 degrees Celsius (°C), lightweight so as not to add excessive weight to the battery pack, and as thin as possible (thickness on the order of millimeters) to keep the overall volume of the battery pack to a minimum.

[0004] Aerogel is one of the best known thermal insulation materials, being flame-retardant, lightweight, and often thin. However, aerogel materials are also very brittle and can easily crack and even shatter. Therefore, aerogel alone is not ideal as a barrier material between cells and modules in EV battery packs. Laminated aerogel materials are also known. Laminated materials containing aerogel can improve the integrity of the aerogel. However, the demand for barrier materials for EV battery pack applications limits which additional laminate layers are suitable in such laminates. The additional laminate layers must still meet the fire resistance requirements of the barrier material and must be lightweight and thin. It is also beneficial that the additional laminate layers do not impair the thermal insulation properties of the aerogel as much as possible. When forming laminates with aerogel to create thermal insulation materials suitable for use in EV battery packs, it is desirable to identify materials that can achieve these objectives. [Overview of the Initiative]

[0005] The present invention provides laminated articles comprising an aerogel containing a specific flame-retardant additive and a polysiloxane. Surprisingly, laminates of these specific materials, by adding the thermal insulation properties of the individual layers, result in a laminated structure with greater thermal insulation properties than expected, exhibiting synergistic thermal insulation properties as a result of laminating the polysiloxane with the aerogel. As a result, the laminated articles exhibit unexpectedly high thermal insulation performance. In fact, the laminated articles can achieve "time to 120°C" results of more than 70 seconds and "time to 120°C per millimeter of thickness" results of more than 15 seconds, even more than 25 seconds, and even more than 40 seconds in the thermal insulation properties tests described herein. At the same time, both the polysiloxane and the aerogel are flame-retardant, as indicated by the absence of flame when directly compressed against a hot plate at a temperature of at least 650°C in the flame resistance test method described herein. Laminates can achieve these properties with a thickness of 10 millimeters or less. Thus, the laminates achieve the desired properties to function as barrier materials for use in EV battery packs.

[0006] In a first aspect, the present invention relates to an article comprising a laminated material, wherein the laminated material comprises an aerogel layer and a polysiloxane layer which is separate from the aerogel layer and in contact with the aerogel layer either directly or through an adhesive that is in direct contact with both the aerogel layer and the polysiloxane layer, wherein the polysiloxane layer comprises polysiloxane and a flame retardant additive dispersed throughout the polysiloxane layer, which is selected from the group consisting of metal hydroxides, mixed metal hydroxides, hydrated metal salts, and any combination thereof, and is more than 5% by weight and not more than 95% by weight based on the weight of the polysiloxane layer. [Modes for carrying out the invention]

[0007] Unless a date is indicated along with the test method number, the test method refers to the test method most recent to the priority date of this document. References to test methods include both references to the testing association and the test method number. The following abbreviations and identifiers for test methods apply in this specification: ASTM refers to ASTM International methods, END refers to European Norm, DIN refers to the German Institute for Standardization, ISO refers to the International Organization for Standardization, and UL refers to the Underwriters Laboratory.

[0008] Products identified by trade names refer to compositions available under those trade names as of the priority date of this document.

[0009] "Multiple" means two or more. "And / or" means "and, or alternatively." All ranges include the endpoint unless otherwise specified.

[0010] The article of the present invention is a laminated material comprising an aerogel layer and a polysiloxane layer separate from the aerogel layer, wherein the aerogel layer and the polysiloxane layer are in contact with each other.

[0011] "Laminate" means that the article includes an aerogel layer and a polysiloxane layer, one of which is superimposed on the other. The laminated material may include multiple aerogel layers and / or multiple polysiloxane layers, provided that at least one aerogel layer and one polysiloxane layer are distinct from each other and in contact with each other (directly or indirectly through an adhesive layer). For example, the article of the present invention may include, or consist of, one aerogel layer and one polysiloxane layer in contact with each other. The article of the present invention may include two polysiloxane layers, each in contact with a single aerogel layer but not in contact with each other, such that the aerogel layer lies between two polysiloxane layers and the polysiloxane layer is in contact with the opposite surface of the aerogel layer. The article may include any number of alternating layers of polysiloxane and aerogel layers.

[0012] The polysiloxane layer may cover the entire outer surface of the aerogel layer, i.e., the polysiloxane layer may surround the aerogel layer. Preferably, the polysiloxane layer covers less than the entire outer surface of the adjacent aerogel layer. Layers of the laminate typically contact the main surface of the adjacent layer. For example, the polysiloxane preferably contacts, and even covers, the main surface of the aerogel layer, regardless of whether it covers the entire outer surface of the aerogel layer or not. The main surface is the surface having the maximum surface area projected onto a plane perpendicular to the surface (to avoid considering contours, spaces, or voids within the surface).

[0013] "Separate" with respect to the layers of a laminate means that the two layers are distinct and identifiable from each other, rather than being completely blended with each other. For example, being separate with respect to an aerogel layer and a polysiloxane layer means that the two layers are identifiable as separate layers, as opposed to being completely blended together or completely dispersed from each other. The laminate of the present invention has a polysiloxane layer in contact with an aerogel layer and is separate from the aerogel layer. This means that the polysiloxane layer is not completely blended with the aerogel layer, and the aerogel layer is not completely blended with the polysiloxane layer. The polysiloxane layer may penetrate to some extent into the surface of the aerogel layer and / or vice versa, but the two layers still remain identifiable from each other as separate layers.

[0014] With respect to the aerogel layer and the polysiloxane layer, "in contact with each other" means either direct contact with each other or indirect contact through an adhesive layer that is in direct contact with both the aerogel layer and the polysiloxane layer. Typically, the adhesive layer is thinner than both the aerogel layer and the polysiloxane layer with which it is in direct contact.

[0015] The polysiloxane layer preferably contains polysiloxane, which is a polysiloxane elastomer (rubber) or gum. Polysiloxane elastomers and gums are well known and can be produced by any known process. Preferably, the polysiloxane elastomer contains 50 mol% (mol%) or more, 60 mol% or more, 70 mol% or more, 80 mol% or more, or 90 mol% or more based on total siloxane units, and RSiO 3 / 2 and R2SiO 2 / 2 It may contain 95 mol% or more of polysiloxane units selected from the units. Polysiloxane units include R3SiO 1 / 2 (M type unit), R2SiO 2 / 2 (Type D unit), RSiO 3 / 2 (Type T unit), and SiO 4 / 2(The "Q" type unit) is a unit in which each R is independently selected from hydrocarbyl and substituted hydrocarbyl groups, the oxygen atoms listed in the unit refer to oxygen bonded to silicon atoms of two different siloxane units, the subscript in oxygen refers to the number of shared oxygen atoms in the molecule, and dividing the molecule by 2 indicates that an oxygen atom is shared with another siloxane unit. Examples of polysiloxane elastomers suitable for use in polysiloxane layers include, for example, crosslinked trimethyl-terminated dimethyl, dimethylvinyl-terminated dimethyl, methylvinylsiloxane gum, or hydroxy-terminated polydimethylsiloxane gum, where the gum has a Williams plasticity of 150-155 mm / 100 mm (according to ASTM D926).

[0016] Polysiloxanes can be elastomers cured from crosslinkable liquid siloxane compositions, for example, by hydrosilylation and / or condensation reactions. Hydrosilylated curable silicone compositions comprise one or more vinyl-containing siloxane polymers and one or more silicon hydride-functionalized siloxanes. At least one of the vinyl-containing siloxane polymers and silicon hydride-functionalized siloxanes contains two or more specific functional groups to act as crosslinking agents. Typically, a hydrosilylation catalyst, such as a platinum compound, is present to facilitate the hydrosilylation reaction. Condensation-curable silicone compositions comprise siloxanes having condensation-curable functional groups, such as any one or more hydroxyl and hydrolyzable functional groups selected from alkoxy, carboxy, amide, enoxy, amino, oxymo, and amioxy groups. Condensation-curable silicone compositions typically further include crosslinking agents such as silanes having hydrolyzable groups, water scavengers such as vinyltrimethoxysilane and methyltrimethoxysilane, and curing catalysts such as titanium and tin compounds, and may be formulated to adjust curing behavior, shelf life, and other post-curing properties. Condensation-curable silicone compositions can be cured at room temperature or high temperatures with or without artificially added moisture in addition to that available from the atmosphere during curing.

[0017] Preferably, the polysiloxane layer is a non-porous film layer; that is, the polysiloxane is a continuous film that is in contact with or further coats the surface of the aerogel layer.

[0018] The polysiloxane layer further comprises a flame retardant additive selected from the group consisting of metal hydroxides, mixed metal hydroxides, hydrated metal salts, and combinations thereof. Preferably, the flame retardant additive is any one additive, any combination of any additives, or two or more additives from the group consisting of aluminum trihydrate and magnesium hydroxide, calcium hydroxide, magnesium carbonate hydroxide, aluminum carbonate hydroxide, boehmite, hydrated magnesium sulfate, magnesium carbonate trihydrate, and magnesium carbonate tetrahydrate. Optionally, the polysiloxane layer may further contain metal carbonates and bicarbonates in combination with metal hydroxides, mixed metal hydroxides, and / or hydrated metal salts to further improve flame retardancy. Examples of metal carbonates and bicarbonates include magnesium carbonate, calcium magnesium carbonate (e.g., commercially available as Hantite), and sodium bicarbonate.

[0019] The flame retardant additive is present in the polysiloxane layer at concentrations of 5% by weight or more, 10% by weight or more, 15% by weight or more, 20% by weight or more, 25% by weight or more, 30% by weight or more, and can be present at concentrations of 35% by weight or more, 40% by weight or more, 45% by weight or more, 50% by weight or more, 55% by weight or more, 60% by weight or more, 65% by weight or more, 70% by weight or more, 75% by weight or more, and even 80% by weight or more. At the same time, it is typically present at concentrations of 95% by weight or less, and can be present at concentrations of 90% by weight or less, 85% by weight or less, 80% by weight or less, 75% by weight or less, 70% by weight or less, 65% by weight or less, 60% by weight or less, 55% by weight or less, and even 50% by weight or less, 45% by weight or less, 40% by weight or less, or 35% by weight or less, and the weight percentage of the flame retardant additive is relative to the weight of the polysiloxane layer.

[0020] The flame retardant additive is dispersed (i.e., distributed) within the polysiloxane layer. Preferably, the flame retardant additive is distributed throughout the polysiloxane layer, and more preferably, it is homogeneously distributed throughout the polysiloxane layer. For example, the polysiloxane may form a continuous polysiloxane matrix within the polysiloxane layer, and the flame retardant additive is dispersed within the continuous polysiloxane matrix.

[0021] The polysiloxane layer may or may not contain any one additional additive or any combination of two or more additional additives. “Additional additives” are additives included in addition to the flame retardant additives already mentioned above. For example, the polysiloxane layer may contain or may not contain silica, calcium silicate, fumed silica, precipitated silica, pulverized quartz, precipitated and pulverized calcium carbonate, calcium silicate, calcium sulfate, magnesium sulfate, barium sulfate, zeolite, TiO2, ZnO, magnesium oxide, iron oxide, boron oxide, wollastonite, perlite, vermiculite, mica, kaolin, glass, glass bubbles, aerogel particles, diatomaceous earth, halloysite, magnetite, hematite; benzotriazole, ammonium polyphosphate, ammonium or aluminum alkyl phosphinate, melamine polyphosphate, antimony oxide. The additive may include any one additional additive or any combination of two or more additional additives selected from the group consisting of halogen-containing flame retardants, dihydrooxaphosphaphenanthrene, zinc stannate, zinc hydroxosutastanate, platinum metals and platinum metal compositions, colorants such as carbon black and pigments (e.g., ultramarine pigment and / or yellow 109), stabilizers such as cerium hydroxide and other flame retardant additives; curing catalysts such as peroxides, organostanates or titanates, and platinum; curing reaction accelerators or moderators such as amines, acetylene alcohols, and organophosphines; and rheological modifiers such as diluents and thickeners.

[0022] The total amount of flame retardant additives and additional additives in the polysiloxane layer is 95% by weight or less based on the weight of the polysiloxane layer, and may be 90% by weight or less, 85% by weight or less, 80% by weight or less, 75% by weight or less, 70% by weight or less, 65% by weight or less, 60% by weight or less, 55% by weight or less, and further 50% by weight or less, 45% by weight or less, 40% by weight or less, or 35% by weight or less, provided that the amount of flame retardant additives is within the range specified for the above flame retardant additives.

[0023] The amount of additional additives is limited only by the requirement that the total amount of additives (flame retardant additive + additional additives) is 95% by weight or less based on the weight of the polysiloxane layer, and may be 90% by weight or less, 85% by weight or less, 80% by weight or less, 75% by weight or less, 70% by weight or less, 65% by weight or less, and even 60% by weight or less. One particular desirable additional additive is calcium silicate, which is included in the polysiloxane layer at concentrations of preferably 6% by weight or more, 7% by weight or more, and even 8% by weight or more, while typically present at concentrations of 70% by weight or less, 60% by weight or less, 50% by weight or less, 40% by weight or less, 30% by weight or less, 20% by weight or less, 15% by weight or less, 10% by weight or less, 9% by weight or less, or even 8% by weight or less.

[0024] The polysiloxane layer is preferably 0.1 mm or thicker, typically 0.2 mm or thicker, 0.3 mm or thicker, 0.4 mm or thicker, 0.5 mm or thicker, 0.6 mm or thicker, 0.7 mm or thicker, 0.8 mm or thicker, 0.9 mm or thicker, 1.0 mm or thicker, 1.2 mm or thicker, 1.2 mm or thicker, 1.4 mm or thicker, 1.6 mm or thicker, 1.8 mm or thicker, and even 2.0 mm or thicker. There are no technical upper limits on the thickness of the polysiloxane layer. However, typically, in combination with any of the lower limits, the polysiloxane can be 10 mm or less, 8 mm or less, 6 mm or less, 4 mm or less, 2 mm or less, 1.0 mm or less, 0.8 mm or less, 0.7 mm or less, 0.6 mm or less, and even 0.5 mm or less in thickness.

[0025] In the broadest scope of the present invention, the aerogel layer can include any aerogel-based material. For example, the aerogel layer can include or consist of an aerogel selected from the group consisting of silica aerogel, metal oxide aerogel, mixed metal oxide aerogel, organic or carbon aerogel, semiconductor metal aerogel, chalcogenide aerogel, metal aerogel, silane and siloxane modified aerogel, and enhanced forms of any of these aerogels. "Aerogel" includes what is known as "xerogel", which is a porous structure typically formed by drying a wet gel and results in a volume shrinkage greater than 10% of more conventionally known supercritically dried aerogels. Enhanced aerogels include aerogels having fiber reinforcement materials such as glass fibers and / or carbon fibers. The fiber reinforced aerogel can have a fiber mat, mesh, or batting within the aerogel material. Such materials are commercially available and can be prepared by placing an aerogel precursor sol within or around a fiber mat, mesh, or batting and then converting the sol to an aerogel having a fiber mat, mesh, or batting with the aerogel. Fiber reinforced silica aerogel is particularly desirable for use as the aerogel layer. If the laminate of the present invention includes two or more aerogel layers, each aerogel layer can be the same or different.

[0026] The aerogel layer typically has a thickness of 0.1 millimeter (mm) or more, 0.5 mm or more, preferably 1 mm or more, 2 mm or more, and can be 3 mm or more, while typically being 50 mm or less, 40 mm or less, 30 mm or less, 20 mm or less, 10 mm or less, 5 mm or less, 4 mm or less, and can be 3 mm or less, or even 2 mm or less.

[0027] The laminated article of the present invention typically has a thickness of 0.5 mm or more, 0.6 mm or more, 0.7 mm or more, 0.8 mm or more, 0.9 mm or more, 1.0 mm or more, 1.25 mm or more, 1.5 mm or more, 1.75 mm or more, 2.0 mm or more, 2.5 mm or more, 3.0 mm or more, 3.5 mm or more, 4.0 mm or more, 4.5 mm or more, 5.0 mm or more, 5.5 mm or more, 6.0 mm or more, 7.0 mm or more, 8.0 mm or more, and even 9.0 mm or more, and at the same time, typically has a thickness of 50.0 mm or less, 40.0 mm or less, 30.0 mm or less, 20.0 mm or less, 10.0 mm or less, 9.0 mm or less, 8.0 mm or less, 7.0 mm or less, 6.0 mm or less, 5.5 mm or less, 5.0 mm or less, 4.5 mm or less, 4.0 mm or less, 3.5 mm or less, 3.0 mm or less, 2.5 mm or less, 2.0 mm or less, 1.5 mm or less, and even 1.0 mm or less. The thickness of the laminated article is determined as the dimension perpendicular to the aerogel and polysiloxane layers.

[0028] The aerogel layer and the polysiloxane layer can be in contact with each other directly or through an adhesive layer. For the broadest scope of the present invention, there is no limitation on the type of adhesive, but preferably, the adhesive is selected from two-component polysiloxane adhesives such as silicone foam adhesives available under the name DOWSIL (trademark) 3-8235 Foam Part A and B (two-component, white, room temperature or heat-cured silicone foam system). DOWSIL is a trademark of The Dow Chemical Company. When an adhesive is used between the aerogel layer and the polysiloxane layer, the adhesive can completely or partially cover the surfaces of the aerogel layer and the polysiloxane layer that are in contact with each other.

[0029] In the broadest sense, there is no limitation on how the laminated article of the present invention can be produced, provided that the above-described properties of the resulting laminated article are achieved. The following Examples section includes specific exemplary methods for making the laminated articles of the present invention both with and without an adhesive between the aerogel layer and the polysiloxane layer.

[0030] A general procedure for preparing a laminate using an adhesive between an aerogel layer and a polysiloxane layer may include the following steps: providing an aerogel layer and a polysiloxane layer containing cured polysiloxane; placing an adhesive on one or both of the aerogel layer surface and the polysiloxane layer surface that are intended to come into contact with each other; and then pressing the aerogel layer and the polysiloxane layer together with the adhesive between the aerogel layer and the polysiloxane layer, with the surfaces that are intended to come into contact with each other coming into contact with each other.

[0031] A general procedure for preparing a laminate without using an adhesive between an aerogel layer and a polysiloxane layer may include the following steps: providing an aerogel layer and a polysiloxane layer containing uncured polysiloxane; positioning the polysiloxane layer on one surface relative to the surface of the aerogel layer; applying pressure to press the aerogel layer and the polysiloxane layer against each other; and heating to cure the polysiloxane in the polysiloxane layer while in contact with the aerogel layer. Preferably, the aerogel layer and the polysiloxane layer are heated and pressurized together in a chase (frame) that defines a desired target thickness of the laminated layer, such that the resulting laminate has a final thickness equal to the chase frame depth. The heating may be at temperatures of, for example, 150°C (°C) or higher, 160°C or higher, 170°C or higher, or even 180°C or higher. The pressure is typically 1 ton or more, and can be 2 tons or more, 3 tons or more, 4 tons or more, 5 tons or more, 10 tons or more, 15 tons or more, 20 tons or more, 25 tons or more, 30 tons or more, 35 tons or more, and even 40 tons or more, while at the same time typically 50 tons or less, even 40 tons or less, 30 tons or less, 20 tons or less, and even 10 tons or less. Pressure and heat are typically applied for 10 minutes or more, 15 minutes or more, 20 minutes or more, 30 minutes or more, 40 minutes or more, and even 50 minutes or more, while at the same time typically pressure and heat are applied for 60 minutes or less, even 50 minutes or less, 40 minutes or less, 30 minutes or less, 20 minutes or less, and even 10 minutes or less.

[0032] A polysiloxane layer can be prepared by combining a flame retardant additive and any additional additives with an uncured polysiloxane elastomer precursor (components of the polysiloxane elastomer before curing, i.e., crosslinking) to form a compounded material. The compounded material can be calendered into a sheet of the desired thickness. If no adhesive is used, the calendered sheet of the compounded material can be used as the polysiloxane layer provided in the general procedure described above. If an adhesive is used, the calendered sheet can be cured by heating to provide a cured sheet of the compounded polysiloxane elastomer that functions as a polysiloxane layer. For curing, heating can be at temperatures of 150°C (°C) or higher, 160°C or higher, 170°C or higher, and even 180°C or higher. Typically, heat is applied for 10 minutes or more, 15 minutes or more, 20 minutes or more, 30 minutes or more, 40 minutes or more, and even 50 minutes or more, while also typically applying heat for 60 minutes or less, even less than 50 minutes, 40 minutes or less, 30 minutes or less, 20 minutes or less, and even less than 10 minutes. Preferably, the polysiloxane layer is heated under pressure in a chase (frame) that defines the desired target thickness of the polysiloxane layer, so that the resulting polysiloxane layer has a final thickness equal to the chase frame depth. The pressure is typically 1 ton or more, and can be 2 tons or more, 3 tons or more, 4 tons or more, 5 tons or more, 10 tons or more, 15 tons or more, 20 tons or more, 25 tons or more, 30 tons or more, 35 tons or more, and even more than 40 tons, while also typically 50 tons or less, even less than 40 tons, 30 tons or less, 20 tons or less, and even less than 10 tons.

[0033] If the uncured polysiloxane is a curable liquid, the polysiloxane may also be applied as a coating layer on the main surface of the aerogel layer and then cured according to the curing conditions described above for the curing reaction.

[0034] The laminated articles of the present invention are useful as fire-resistant and thermal barriers. In particular, the laminated articles of the present invention are useful as barrier materials between battery cells in battery packs, such as those useful in electric vehicles. In such applications, the laminated articles are located between the battery cells of the battery pack. For this application, the laminated articles preferably have at least three layers, with two polysiloxane layers, one on each side of an aerogel layer, where the polysiloxane layers are close to the battery cells and the aerogel interior is between the polysiloxane layers. The laminated articles can also be used as thermal insulation somewhere else inside and around a battery pack. One such additional application is insulation between the top of a battery pack and the bottom of a vehicle's passenger compartment, where the battery pack is assembled on the bottom of the passenger compartment. The laminated articles can also be placed under the cover of a battery pack to slow down the temperature rise of the cover in the event of a battery failure. More generally, the laminated articles are useful in any situation where it is necessary to slow down the heat flow from a high-temperature location to an adjacent location. [Examples]

[0035] Table 1 lists the components required to prepare the following samples.

[0036] [Table 1-1]

[0037] [Table 1-2] * The viscosity of the silicone fluid is determined using a Brookfield LV viscometer equipped with a cone + plate spindle #CP-52. **Number-average molecular weight is determined by gel permeation chromatography using a Waters 515 pump, Waters 717 autosampler, and Waters 2410 differential refractometer. Separation is performed using two 300 mm × 7.5 mm Polymer Laboratories PLgel 5 micrometer Mixed-C columns (molecular weight separation range 200 to 2,000,000, preceded by a PLgel 5 micrometer guard column (50 mm × 7.5 mm)). HPLC-grade toluene flowing at 1.0 ml / min is used as the eluent, and analysis is performed at 45°C using the column and detector. Samples are prepared in toluene with a solid content of approximately 0.4 wt / vol%, solvated for approximately 16 hours with occasional shaking, and then filtered through a 0.45 micrometer polytetrafluoroethylene syringe filter before analysis. Data is collected for 25 minutes using a 75 microliter injection volume. ThermoLabsystems Atlas chromatography software and Polymer Laboratories Cirrus GPC software are used for data acquisition and analysis. The average molecular weight is determined for a tertiary calibration curve prepared using polystyrene standards covering the molecular weight range of 580 to 1,300,000. In this specification, molecular weight is reported in g / mol units. The refractive index is measured at 45°C using the sodium D line (589 nm).

[0038] XIAMETER is a trademark of Dow Corning Corporation. DOWSIL is a trademark of The Dow Chemical Company. VAROX is a trademark of Vanderbilt Chemicals, LLC. HALTEX is a trademark of TOR Minerals International, Inc. ZEROGEN is a trademark of JMHuber Corporation. ADIN is a trademark of Tolsa. Wollastocoat and Wollstonite are trademarks of NYCO Minerals, Inc. MIN-U-SIL is a trademark of USSilica Company. CAB-O-SIL is a trademark of Cabot Corporation. HARBORLITE is a trademark of Imerys Perlite USA. MAGOX is a trademark of Premier Magnesium, LLC.

[0039] Preparation of polysiloxane-based formulations Base 1. Combine 31-38% by weight of G1, 31-38% by weight of G2, and 23-29% by weight of silica 2. Prepare according to the standard mixing procedure described in ASTM D3182.

[0040] Base 2. Combine 52-64% by weight of G1, 0.9-2.0% by weight of F2, and 34-42% by weight of Silica 2. Prepare according to the standard mixing procedure described in ASTM D3182.

[0041] Base 3. Combine 33-41% by weight of G1, 32-42% by weight of G2, and 0.3-0.8% by weight of F2, 20-29% by weight of silica 2, and 0.2-0.8% by weight of magnesium oxide. Prepare according to the standard mixing procedure described in ASTM D3182.

[0042] Base 4. Combine 61-71% by weight of G1 and 26-36% by weight of silica 2. Prepare according to the standard mixing procedure described in ASTM D3182.

[0043] Preparation of additives A1. A masterbatch of 50% by weight of cerium hydroxide in gum 3. Prepare according to the standard mixing procedure described in ASTM D3182.

[0044] A2. A proprietary pigment-based flame retardant additive containing benzotriazole dispersed in silicone. Available from The Dow Chemical Company as XIAMETER® RBM-9006.

[0045] A3. A masterbatch of 38–56 wt% CIPigment Black 26 and 13–19 wt% silicon dioxide in Base 4. Prepare according to the standard mixing procedure as described in ASTM D3182.

[0046] A4. A masterbatch of 2-10 wt% magnesium ferrite, 10-40 wt% ultramarine pigment, and 10-40 wt% titanium dioxide in gum 1. Prepare according to the standard mixing procedure as described in ASTM D3182.

[0047] A5. A masterbatch of magnesium oxide at 45–55% by weight in gum 1. Prepare according to the standard mixing procedure as described in ASTM D3182.

[0048] A6. Platinum-divinyltetramethyldisiloxane complex (0.5 wt% platinum available from Sigma Aldrich as a Karstedt catalyst).

[0049] A7. A masterbatch of 62–69% by weight of iron oxide in gum 1. Prepare according to the standard mixing procedure as described in ASTM D3182.

[0050] A8. Masterbatch of yellow pigment in a concentration of 23–28% by weight in gum 1. Prepare according to the standard mixing procedure as described in ASTM D3182.

[0051] Preparation of compounds Compound 1. Combine 100 parts by weight ("parts") of B1, 78.6 parts of G1, 195.9 parts of alumina trihydrate, 117.5 parts of magnesium hydroxide, 4.7 parts of magnesium silicate, 47 parts of calcium metasilicate, 15.6 parts of A2, 1.4 parts of F4, 16.4 parts of A4, 0.4 parts of A8, and 6.2 parts of P2. Prepare according to the standard mixing procedure described in ASTM D3182.

[0052] Compound 2. 100 parts of B3, 90 parts of calcium metasilicate, 0.2 parts of A6, and 0.9 parts of P2. Prepare according to the standard mixing procedure described in ASTM D3182.

[0053] Compound 3. 100 parts B3, 90 parts calcium metasilicate, 1.7 parts A6, 0.9 parts P2. Prepare according to the standard mixing procedure described in ASTM D3182.

[0054] Compound 4. 100 parts B3, 90 parts calcium metasilicate, 1.7 parts A6, 0.9 parts P2, 1.5 parts A1. Prepare according to the standard mixing procedure described in ASTM D3182.

[0055] Compound 5. 28.6 parts B1, 71.4 parts B2, 0.8 parts F5, 1.3 parts A7, 4.2 parts A3, 28.6 parts amorphous alumina silicate, 0.6 parts magnesium hydroxide, 1.3 parts P1. Prepared according to the standard mixing procedure described in ASTM D3182.

[0056] Sample preparation and characterization Three different types of samples—a reference sample, a comparative sample, and an exemplary sample—are prepared as described below. Each sample is characterized for its flame resistance and thermal insulation properties using the following method.

[0057] Characterization of the sample - thermal insulation properties and flame resistance Thermal insulation properties. The hot plate is placed in a hydraulic environment surrounded by a vented space on one side, with the vent port directly adjacent to the sample. A porous ceramic refractory insulator is placed on the upper surface of the hot plate, and the hot plate is heated to 710°C. Four thermocouple probes are attached to an aluminum heat sink using Kapton tape. The sample is placed on the aluminum heat sink and secured to the aluminum heat sink using Kapton tape. Another thermocouple is secured to the sample surface using Kapton tape. The insulator is removed from the heated surface of the hot plate, and the sample is quickly placed on the heated surface of the hot plate with the aluminum heat sink on the opposite side of the hot plate from the sample. A pressure of 255 kilopascals is rapidly applied to compress the sample against the hot plate. The temperature of the hot plate surface and the sample is monitored using a data logger. When the temperature on the sample side opposite the hot plate reaches 180°C, the pressure is released and the test is terminated. The time required for the sample side opposite the hot plate to reach 120°C is recorded as the adiabatic time in seconds. The adiabatic time is divided by the thickness of the sample to provide the adiabatic value in seconds / millimeter (seconds / mm). Higher adiabatic times and values ​​correspond to greater adiabatic properties of the sample.

[0058] For flame resistance, the sample is observed during the thermal insulation test to see if it ignites. If flames are observed, note whether they self-extinguish within the test time (the time required to reach 180°C). If the sample ignites and does not self-extinguish within the test time, the flames can be observed beyond the test time. General observations indicate that a sample that will ignite will generally ignite within the first 5 seconds after contact with the hot plate. If the sample ignites during the test time, it fails the flame resistance test.

[0059] Reference sample The reference sample consists of individual aerogel layers and individual polysiloxane layers. The reference sample is characterized to determine how each of the individual layers of the example sample functions independently of the other layers in the example sample.

[0060] Reference sample 1 (R1) is aerogel 1 (4 mm thick). R1 ​​has an adiabatic time of 28 seconds and an adiabatic value of 7.0 seconds / mm, and passes the flame resistance test without flame.

[0061] Reference sample 2 (R2) is aerogel 1 (2 mm thick). R2 has an adiabatic time of 134 seconds and an adiabatic value of 67.0 seconds / mm, and passes the flame resistance test without flame.

[0062] Reference samples 3-13 (R3-R13) are polysiloxane layers. The polysiloxane layers were prepared by mixing the sample components together according to the standard mixing procedure of ASTM D3182 and calendering them using a two-roll mill according to ASTM D3182 to form sheets with a thickness of 3 mm. Sheets R1 and R7-R13 were cured at 120°C for 15 minutes in a hot press at 30 tons of pressure on a 3 mm thick metal chase. Sheets R4-R7 were cured at 170°C for 20 minutes, and then characterized in a hot press at 30 tons of pressure on a 3 mm thick metal chase.

[0063] Table 2 provides the compositions and test results for R3 to R13. The compositions are listed by the weight in grams of each component in the formulation. Table 2 also provides the test results for R3 to R13.

[0064] [Table 2]

[0065] Comparative sample The comparative sample is a three-layer laminate with polysiloxane layers on both sides of an aerogel layer. The two polysiloxane layers are identical to each other and each has a thickness of 0.6 mm.

[0066] Comparative sample 1 (CS1) - Additive-free polysiloxane layer. S1 is prepared by forming two additive-free polysiloxane layers. For each polysiloxane layer, 98.9 g of B3 and 1.07 g of P1 are mixed together, and the mixed material is then calendered to a sheet with a thickness of 0.6 mm. The polysiloxane layer sheet is cured at 170°C for 20 minutes in a hot press under a pressure of 30 tons on a 3 mm thick metal chase. Using a static mixer, a portion of the two-part silicone adhesive is mixed together and a thin layer is applied to the main surfaces on both opposite sides of the Aerogel 2 sheet, and then the cured polysiloxane layer sheet is placed against the adhesive layer to form a polysiloxane layer-adhesive layer-aerogel layer-adhesive layer-polysiloxane layer sandwich structure. The sandwich structure is placed on a metal frame with a depth of 4 mm. A force of 10 tons is applied to the laminated structure and the layers are pressed together at 25°C for 30 minutes. The resulting laminated structure is CS1, with a thickness of 3.5 mm. CS1 has an adiabatic time of 114 seconds and an adiabatic value of 32.6 seconds / mm, and fails the flame resistance test.

[0067] Comparative sample 2 (CS2) - Polysiloxane layer without flame retardant additives. S2 is prepared by laminating a 0.6 mm thick polysiloxane sheet having composition R8 on the opposite main surface of aerogel 2 without using adhesive. Two polysiloxane layers are prepared by mixing the R8 formulation together and calendering each to a thickness of 0.6 mm. Before curing, the polysiloxane layers are placed on either side of a 2 mm thick sheet of aerogel 2 to form a sandwich structure. The sandwich structure is placed on a metal frame having a depth of 4 mm. A force of 10 tons is applied to the laminated structure in a 3 mm thick chase, and the layers are pressed together at 120°C for 20 minutes. The pressed laminated structure is cured at 170°C for 20 minutes to obtain CS2 having a thickness of 3.5 mm. CS2 has an adiabatic time of 156 seconds and an adiabatic value of 44.6 seconds / mm, and fails the flame resistance test.

[0068] Comparative sample 3 (CS3) - Polysiloxane layer without flame retardant additives. S3 was prepared in the same manner as CS2, except that the polysiloxane layer used the R9 formulation. CS3 failed the flame resistance test and ignited before the adiabatic time or value could be determined.

[0069] The comparative sample demonstrates that the laminated structure having a polysiloxane layer without the flame-retardant additive of the present invention fails the flame resistance test and subsequent results.

[0070] Exemplary sample The example samples represent laminated articles that passed the flame resistance test and exhibited unexpectedly high thermal insulation properties (i.e., thermal insulation values ​​greater than the sum of the layers). The composition and evaluation results of the example samples are shown in Table 3 (component values ​​are in grams), and the example samples are listed below in Table 3.

[0071] Exemplary sample 1 (IS1): Aerogel 1 + polysiloxane layer of R3 with adhesive. IS1 is prepared in the same manner as CS1, except that aerogel 1 is used instead of aerogel 2 and the R3 formulation is used for the polysiloxane layer. The resulting laminate has a thickness of 5.5 mm, with a 4 mm aerogel layer and two polysiloxane layers, each 0.6 mm thick.

[0072] Exemplary sample 2 (IS2): Adhesive-free aerogel 1 + polysiloxane layer of R3. IS2 is prepared in the same manner as CS2, except that aerogel 1 is used instead of aerogel 2 and the R3 formulation is used for the polysiloxane layer. The resulting laminate has a thickness of 4.5 mm, with a 4 mm aerogel layer and two polysiloxane layers, each 0.6 mm thick.

[0073] Exemplary sample 3 (IS3): Aerogel 2 + polysiloxane layer of R3 with adhesive. IS3 is prepared in the same manner as IS1, except that aerogel 2 is used instead of aerogel 1. The resulting laminate has a thickness of 4 mm, with a 2 mm aerogel layer and two polysiloxane layers, each 0.6 mm thick.

[0074] Exemplary sample 4 (IS4): A modified R3 aerogel 2 + polysiloxane layer without adhesive. IS4 is prepared in the same manner as IS2, except that aerogel 2 is used instead of aerogel 1 and a modified R3 formulation is used for the polysiloxane layer. The resulting laminate has a thickness of 3.5 mm, with a 2 mm aerogel layer and two polysiloxane layers, each with a thickness of 0.6 mm.

[0075] Exemplary sample 5 (IS5): A modified R3 aerogel 2 + polysiloxane layer without adhesive. IS5 is prepared in the same manner as IS2, except that aerogel 2 is used instead of aerogel 1 and a modified R3 formulation is used for the polysiloxane layer. The resulting laminate has a thickness of 3.5 mm, with a 2 mm aerogel layer and two polysiloxane layers, each with a thickness of 0.6 mm.

[0076] Exemplary sample 6 (IS6): A modified R3 aerogel 2 + polysiloxane layer without adhesive. IS6 is prepared in the same manner as IS2, except that aerogel 2 is used instead of aerogel 1 and a modified R3 formulation is used for the polysiloxane layer. The resulting laminate has a thickness of 3.5 mm, with a 2 mm aerogel layer and two polysiloxane layers, each 0.6 mm thick.

[0077] Exemplary sample 7 (IS7): A modified R3 aerogel 2 + polysiloxane layer without adhesive. IS7 is prepared in the same manner as IS2, except that aerogel 2 is used instead of aerogel 1 and a modified R3 formulation is used for the polysiloxane layer. The resulting laminate has a thickness of 3.5 mm, with a 2 mm aerogel layer and two polysiloxane layers, each with a thickness of 0.6 mm.

[0078] Exemplary sample 8 (IS8): A modified R3 aerogel 2 + polysiloxane layer without adhesive. IS8 is prepared in the same manner as IS2, except that aerogel 2 is used instead of aerogel 1 and a modified R3 formulation is used for the polysiloxane layer. The resulting laminate has a thickness of 3.5 mm, with a 2 mm aerogel layer and two polysiloxane layers, each 0.6 mm thick.

[0079] Table 3 shows a comparison between the adiabatic time of the example sample and the expected adiabatic time of the laminate based on the sum of the individual layers. The expected adiabatic time is the sum of the adiabatic times for each layer of the sample. For example, the expected adiabatic time of IS1 is calculated as follows: ● Layer 1 is a polysiloxane layer R3 with a thickness of 0.6 mm, and therefore the expected adiabatic time is (0.6 mm)(6.7 sec / mm) = 4.02 sec. ● Since layer 2 is aerogel 2 (R1), the expected adiabatic time is 28 seconds. ● Since layer 3 = layer 1, the expected adiabatic time is 4.02 seconds.

[0080] The overall expected adiabatic time for IS1 is (4.0 seconds) + (28 seconds) + (4.0 seconds) = 36 seconds.

[0081] Surprisingly, all of the example samples exhibited thermal insulation values ​​exceeding the expected values, suggesting some synergistic performance obtained from laminating the layers together to form a laminated article, within the scope of the present invention.

[0082] [Table 3]

[0083] Investigation of the lower limit of flame retardant additives Additional laminates were prepared using aerogel 2 and polysiloxane layers R10-R13 to explore the lower limit of flame retardant required to pass flame resistance tests. The resulting laminates were CS4 (using R11 as the polysiloxane layer) and IS9-IS11 (using R10, R12, and R13 as the polysiloxane layers).

[0084] The sample is prepared in the same manner as IS4, except that the polysiloxane layers specified in Table 4 are used for the two polysiloxane layers.

[0085] Table 4 includes the characterization evaluations for CS4 and IS9-IS11.

[0086] [Table 4]

[0087] The CS4 results in Table 4 show that when the polysiloxane layer contains 5% by weight of a flame retardant additive (aluminum trihydrate), even if the polysiloxane layer itself (R11) passes the flame resistance test, the laminate fails the flame resistance test. As long as the concentration of the flame retardant additive exceeds 5% by weight, the laminate will pass the flame resistance test.

[0088] The thermal insulation performance for IS9-IS11 is expected to follow the remarkable results trend shown for IS1-IS8, which indicates synergistic thermal insulation performance from the combined lamination of layers to form the laminated article. The invention described in the original claims of this application is listed below. [1] Article comprising a laminated material, the laminated material comprising an aerogel layer and a polysiloxane layer which is separate from the aerogel layer and is in contact with the aerogel layer either directly or through an adhesive that is in direct contact with both the aerogel layer and the polysiloxane layer, wherein the polysiloxane layer comprises a polysiloxane and a flame retardant additive dispersed throughout the polysiloxane layer, which is selected from the group consisting of metal hydroxides, mixed metal hydroxides, hydrated metal salts, and any combination thereof, and is more than 5% by weight and not more than 95% by weight based on the weight of the polysiloxane layer. [2] The article according to [1], wherein the polysiloxane layer is a polysiloxane rubber matrix in which the flame retardant additive is dispersed. [3] The article according to [1] or [2], wherein the polysiloxane layer has a thickness of 0.2 millimeters or more. [4] The article according to any one of [1] to [3], wherein the polysiloxane layer has a thickness of 0.5 to 1.0 millimeters. [5] The article according to any one of [1] to [4], wherein the flame retardant additive is any one additive or any combination of two or more additives from the group consisting of aluminum trihydrate and magnesium hydroxide, calcium hydroxide, magnesium carbonate hydroxide, aluminum carbonate hydroxide, boehmite, magnesium sulfate hydrate, magnesium carbonate trihydrate, and magnesium carbonate tetrahydrate. [6] The article according to any one of [1] to [5], wherein the polysiloxane layer contains additional additives dispersed therein, in addition to the metal hydroxide, mixed metal hydroxide, and hydrated metal salt flame retardant additives, provided that the total amount of the additional additives and the metal hydroxide, mixed metal hydroxide, and hydrated metal salt flame retardant additives is 95 percent by weight or less of the weight of the polysiloxane layer. [7] The article according to any one of [1] to [6], wherein the aerogel of the aerogel layer is selected from the group consisting of silica aerogel, metal oxide aerogel, mixed metal oxide aerogel, organic or carbon aerogel, semiconductor metal aerogel, chalcogenide aerogel, metal aerogel, silane and siloxane modified aerogel, and any reinforced form of any of these aerogels. [8] The article according to any one of [1] to [7], wherein the laminated material has a thickness of less than 10 millimeters. [9] The article according to any one of [1] to [8], wherein the laminated material further comprises a second polysiloxane layer positioned such that two polysiloxane layers are on opposite sides of the aerogel, the second polysiloxane layer being in contact with the aerogel layer either directly or through an adhesive that is in direct contact with both the aerogel layer and the second polysiloxane layer, and the polysiloxane comprises a flame retardant additive of more than 5% by weight and not more than 95% by weight based on the weight of the polysiloxane, selected from metals and mixed metal hydroxides dispersed in the polysiloxane matrix.

[10] The article according to any one of [1] to [9], wherein the article comprises the laminated material located between the battery cells of a battery pack.

Claims

1. An article comprising a laminated material, wherein the laminated material comprises an aerogel layer and a polysiloxane layer, which is separate from the aerogel layer and in contact with the aerogel layer either directly or through an adhesive that is in direct contact with both the aerogel layer and the polysiloxane layer, wherein the polysiloxane layer comprises polysiloxane and a flame retardant additive dispersed throughout the polysiloxane layer, which is selected from the group consisting of metal hydroxides, mixed metal hydroxides, hydrated metal salts, and any combination thereof, and is between 5% and 95% by weight based on the weight of the polysiloxane layer. The polysiloxane layer does not contain any other flame retardant additives besides the aforementioned flame retardant additive. Goods.

2. The article according to claim 1, wherein the polysiloxane layer is a polysiloxane rubber matrix in which the flame retardant additive is dispersed.

3. The article according to claim 1 or 2, wherein the polysiloxane layer has a thickness of 0.2 millimeters or more.

4. The article according to any one of claims 1 to 3, wherein the polysiloxane layer has a thickness of 0.5 to 1.0 millimeters.

5. The article according to any one of claims 1 to 4, wherein the flame retardant additive is any one additive or any combination of two or more additives from the group consisting of aluminum trihydrate and magnesium hydroxide, calcium hydroxide, magnesium carbonate hydroxide, aluminum carbonate hydroxide, boehmite, magnesium sulfate hydrate, magnesium carbonate trihydrate, and magnesium carbonate tetrahydrate.

6. The article according to any one of claims 1 to 5, wherein the polysiloxane layer contains additional additives dispersed therein, in addition to the metal hydroxide, mixed metal hydroxide, and hydrated metal salt flame retardant additives, provided that the total amount of the additional additives and the metal hydroxide, mixed metal hydroxide, and hydrated metal salt flame retardant additives is 95 percent by weight or less of the weight of the polysiloxane layer.

7. The article according to any one of claims 1 to 6, wherein the aerogel of the aerogel layer is selected from the group consisting of silica aerogel, metal oxide aerogel, mixed metal oxide aerogel, organic or carbon aerogel, semiconductor metal aerogel, chalcogenide aerogel, metal aerogel, silane and siloxane modified aerogel, and any reinforced form of these aerogels.

8. The article according to any one of claims 1 to 7, wherein the laminated material has a thickness of less than 10 millimeters.

9. The article according to any one of claims 1 to 8, wherein the laminated material further comprises a second polysiloxane layer positioned such that two polysiloxane layers are on opposite sides of the aerogel layer, the second polysiloxane layer being in contact with the aerogel layer either directly or through an adhesive that is in direct contact with both the aerogel layer and the second polysiloxane layer, and the polysiloxane comprises a flame retardant additive of more than 5% and 95% by weight, based on the weight of the polysiloxane, selected from metals and mixed metal hydroxides dispersed in the polysiloxane matrix.

10. The article according to any one of claims 1 to 9, wherein the article includes the laminated material located between the battery cells of the battery pack.

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