High thermal conductivity layered phase change composites

Abstract

In one embodiment, a layered phase change composite includes a phase change layer including a phase change material, a plurality of boron nitride particles, and a binder; and first and second capping layers positioned on opposite sides of the phase change layer. In another embodiment, a method of making a layered phase change composite includes forming a first capping layer from a first composition, vibrating the phase change composition on a three-way vibration stage to form a phase change layer from the phase change composition, and forming a second capping layer from a second composition.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 62 / 958,644, filed January 8, 2020. The related applications are incorporated by reference herein in their entireties. Disclosed herein are layered phase change composites with high thermal conductivity. [Background technology]

[0002] Circuit designs for electronic devices such as televisions, radios, computers, medical equipment, business machines, and communication equipment are becoming increasingly smaller and thinner. The increasing power of such electronic components is resulting in increased heat generation. Furthermore, smaller electronic components are being tightly packed into ever-smaller spaces, resulting in more intense heat generation. At the same time, temperature-sensitive elements in electronic devices often need to be maintained within specified operating temperatures to avoid significant performance degradation or even system failure. Thus, manufacturers continue to face challenges in dissipating the heat generated in electronic devices.

[0003] There continues to be a need for new approaches to thermal management in various devices, particularly electronic devices, and an increasing demand for electrical insulating materials with enhanced heat dissipation capabilities. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 5,898,009 [Patent Document 2] U.S. Patent No. 6,048,511 [Patent Document 3] U.S. Patent Application Publication No. 2005 / 0041373 [Patent Document 4] U.S. Patent No. 6,951,583 Summary of the Invention [Problem to be solved by the invention]

[0005] Disclosed herein are layered phase change composites with high thermal conductivity. [Means for solving the problem]

[0006] In one embodiment, the layered phase change composite includes a phase change layer including a phase change material, a plurality of boron nitride particles, and a binder; and a first capping layer and a second capping layer positioned on either side of the phase change layer.

[0007] In another aspect, a method for manufacturing a layered phase change composite includes forming a first capping layer from a first composition; forming a phase change layer from the phase change composition, the phase change layer including vibrating the phase change composition on a three-way vibration stage; and forming a second capping layer from a second composition.

[0008] In yet another aspect, the article can include a layered phase change composite.

[0009] These and other features are exemplified by the following figures, detailed description and claims.

[0010] The figures are of illustrative embodiments, and like elements have similar numbers. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is an illustration of an embodiment of a high thermal conductivity layered phase change composite. [Figure 2] 1 is a top-down microscope image of the phase-change layer of Example 1 after curing. [Figure 3] 1 is a scanning electron microscope image of a cross section of the layered phase change composite of Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0012] Phase change materials (PCMs) are substances with high heats of fusion that can absorb and release large amounts of latent heat during phase transitions, such as melting and solidification, respectively. During the phase change, the temperature of the phase change material (referred to herein as the transition temperature) remains nearly constant, essentially inhibiting or halting the flow of thermal energy through the material. In this manner, heat can be reversibly stored and removed from the phase change material. While a solid block of phase change material has a very large theoretical capacity to absorb heat, the process is generally not fast due to the difficulty of heat transfer throughout the material. Therefore, developing articles containing phase change materials for various applications requiring faster heat transfer into and out of the material is a challenge.

[0013] To increase heat transfer into and out of a phase change material, a layered phase change composite including a phase change layer has been developed. The phase change layer includes a phase change material, a plurality of boron nitride particles, and a binder. When the phase change layer includes boron nitride particles, a surprising increase in the rate of heat transfer into and out of the phase change layer was achieved. The combination of boron nitride particles and a phase change material can be particularly advantageous for use as a thermal management material, especially in electronics, because the high crystallinity of the phase change material can enable a combination of high latent heat capacity and energy absorption, while the boron nitride can provide higher thermal conductivity and electrical insulation. This combination of properties can lead to improved thermal management, lower heat buildup, fewer problems, and better management of temperature discontinuities. The layered phase change composite can provide an article with improved thermal stability, thereby reducing performance degradation and increasing the article's service life.

[0014] Furthermore, it was discovered that when a phase change layer is formed during vibration in three directions, the boron nitride particles, particularly the platelets, in the phase change material can be aligned perpendicular to the broad surface of the phase change layer. The perpendicular alignment of the boron nitride particles can further increase the thermal conductivity of the phase change layer.

[0015] An embodiment of a layered phase change composite including a phase change layer with first and second capping layers positioned on either side of the phase change layer is illustrated in FIG. 1. FIG. 1 illustrates a phase change layer 50 including a plurality of boron nitride particles 52 and a phase change material 54. Capping layers 10 and 20 are positioned on either side of the phase change layer 50. First capping layer 10 includes a first plurality of boron nitride particles 12 in a first polymer 14, and second capping layer 20 includes a second plurality of boron nitride particles 22 in a second polymer 24. First capping layer 10 and second capping layer 20 are in direct physical contact with phase change layer 50. The thickness of phase change layer 50 can be 0.05 to 10 millimeters (mm), or 0.5 to 2 mm, or 0.5 to 1.5 mm. The first capping layer 10 and the second capping layer 20 can each independently have a layer thickness of 0.001 to 1 mm, or 0.01 to 0.5 mm.

[0016] The layered phase change composite can have a heat of fusion of at least 50 joules per gram (J / g), or at least 75 J / g, or at least 100 J / g, or at least 240 J / g, or from 50 to 150 J / g, as measured according to ASTM D3418-15. The layered phase change composite can have a thermal conductivity of greater than 0.5 watts per meter Kelvin (W / mK), or from 0.5 to 1 W / mK, as measured according to ASTM D5470-17.

[0017] Phase change materials have characteristic transition temperatures. The term "transition temperature" refers to the approximate temperature at which a material transitions between two states. The transition temperature can refer to a single temperature or a range of temperatures over which the transition occurs, such as in the case of paraffin wax. The choice of phase change material can depend on the transition temperature desired for the particular application in which the phase change material is intended. For example, phase change materials have transition temperatures near normal body temperature, or approximately 37 degrees Celsius (°C). Phase change materials can have transition temperatures between -5 and 150°C; such temperatures can be desirable in electronic applications to prevent user injury and protect components from overheating. However, in general, phase change materials can have transition temperatures between -100 and 150°C, or between -5 and 150°C, or between 0 and 90°C, or between 30 and 70°C, or between 35 and 50°C. The phase change material can have a transition temperature of 25-105°C, or 28-60°C, or 45-85°C, or 60-80°C, or 80-100°C. The phase change material can have a phase transition temperature of 5-70°C, 20-65°C, 25-60°C, or 30-50°C, or 35-45°C. In particular, for use in LEDs and electronic components, the phase change material incorporated into the phase change composition can have a transition temperature of 0-115°C, 10-105°C, 20-100°C, or 30-95°C.

[0018] The transition temperature can be broadened or narrowed by modifying the purity of the phase change material, modifying the molecular structure, blending two or more phase change materials, or any combination thereof. For example, a phase change material containing at least two or more different phase change materials may exhibit two or more different transition temperatures, or a single modified transition temperature. Having multiple or broad transition temperatures can be advantageous because it can increase the amount of heat transferred as latent heat, thereby slowing the transfer of sensible heat. Phase change materials containing multiple or broad transition temperatures can therefore more efficiently assist in conducting heat by absorbing overlapping or overlapping heat from neighboring components. For example, if a phase change composition includes a first phase change material (PCM1) that absorbs at 35-40°C and a second phase change material (PCM2) that absorbs at 38-45°C, once the phase change composition reaches a temperature of 35°C, PCM1 can begin to absorb heat as latent heat until its phase change is complete, during which time PCM2 can begin to absorb heat as latent heat until its phase change is complete at a temperature of 45°C, increasing the temperature range over which heat is absorbed as latent heat.

[0019] It is noted that the ability of a phase change material to absorb heat as latent heat during a phase change is temporary, and further heat transfer after the phase change results in an increase or decrease in sensible heat, raising or lowering the temperature of the phase change material.

[0020] The selection of a phase change material can be based on its latent heat of fusion, or the amount of energy absorbed or released when the phase change material undergoes a phase change per unit of material. The phase change material can have a latent heat of fusion that is at least 20 joules per gram (J / g), or at least 40 J / g, or at least 50 J / g, or at least 70 J / g, or at least 80 J / g, or at least 90 J / g, or at least 100 J / g. The phase change material can have a latent heat of fusion between 50 and 400 J / g, or between 60 and 400 J / g, or between 80 and 400 J / g, or between 100 and 400 J / g. The phase change material can have a latent heat of fusion equal to or greater than 150 J / g, or equal to or greater than 180 J / g, or equal to or greater than 200 J / g. The heat of fusion of a phase change material can be determined by differential scanning calorimetry according to ASTM D3418-15.

[0021] Phase change materials that can be used include a variety of organic and inorganic substances. Phase change materials include organic compounds (e.g., straight chain alkanes or paraffinic hydrocarbons, branched alkanes, unsaturated hydrocarbons (e.g., alkenes or alkynes), alicyclic hydrocarbons, halogenated hydrocarbons (e.g., 1-halides), or aromatic compounds or arenes), fatty acids (e.g., caproic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, or cerotic acid), dibasic acids, fatty acid esters (e.g., methyl octanoate, methyl caprate, methyl laurate, methyl myristate, etc.), and the like. methyl palmitate, methyl stearate, methyl arachidate, methyl behenate, or methyl lignocerate), methyl esters, dibasic acid esters, alcohols [e.g., primary alcohols, secondary alcohols, tertiary alcohols, polyhydric alcohols (e.g., 2,2-dimethyl-1,3-propanediol, 2-hydroxymethyl-2-methyl-1,3-propanediol, ethylene glycol, polyethylene glycol, pentaerythritol, dipentaerythritol, pentaglycerin, tetramethylolethane, neopentyl ether, butyl glycol, tetramethylolpropane, 2-amino-2-methyl-1,3-propanediol, monoaminopentaerythritol, diaminopentaerythritol, or tris(hydroxymethyl)acetic acid, fatty alcohols (e.g., caprylic alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, lignoceryl alcohol, ceryl alcohol, montanyl alcohol, myricyl alcohol, or gedil alcohol), sugar alcohols (e.g., erythritol, D-mannitol, galactitol, xylitol, or D-sorbitol)], hydrated salts (e.g., calcium chloride hexahydrate, calcium bromide hexahydrate, magnesium nitrate hexahydrate, lithium nitrate trihydrate, potassium fluoride tetrahydrate, ammonium alum, magnesium chloride hexahydrate, sodium carbonate decahydrate, disodium phosphate dodecahydrate, sodium sulfate decahydrate, or sodium acetate trihydrate), polymers (e.g., polyethylene, poly(ethylene glycol), polypropylene, poly(propylene glycol)), Poly(ethylene glycol), poly(tetramethylene glycol), poly(propylene malonate), poly(neopentyl glycol sebacate), poly(pentane glutarate), poly(vinyl myristate), poly(vinyl stearate), poly(vinyl laurate), poly(hexadecyl methacrylate), poly(octadecyl methacrylate)], polyesters produced by polycondensation of glycols (or their derivatives) with diacids (or their derivatives), copolymers (e.g., polyacrylates or poly(meth)acrylates having alkyl hydrocarbon side chains or polyethylene glycol side chains, or copolymers comprising at least one of polyethylene, poly(ethylene glycol), polypropylene, poly(propylene glycol), or poly(tetramethylene glycol)), anhydrides (e.g., stearic anhydride), silicone waxes, clathrates, hemi-clathrates, gas clathrates, ethylene carbonate, oils (e.g., vegetable oils (e.g., soybean oil, palm oil, or castor oil)), ], water, or metal. The phase change materials may include an oil agent that can be purified or otherwise processed to make them suitable for use as a phase change material. The phase change materials used in the phase change composition may be organic.

[0022] The phase change material may include at least one of a paraffinic hydrocarbon, a fatty acid, or a fatty acid ester. The paraffinic hydrocarbon may be represented by the formula C n H n+2 where n may be 10-44 or 10-36. The transition temperature and heat of fusion of a homologous series of paraffinic hydrocarbons, a homologous series of fatty acids, or a homologous series of fatty acid esters may be directly related to the number of carbon atoms. The phase change material may include at least one of a paraffinic hydrocarbon, a fatty acid, or a fatty acid ester having 15-40 carbon atoms, 18-35 carbon atoms, or 18-28 carbon atoms. The phase change material may be a single paraffinic hydrocarbon, fatty acid, or fatty acid ester, or a mixture of hydrocarbons, fatty acids, or fatty acid esters. The phase change material may include vegetable oil.

[0023] The amount of phase change material in the phase change layer can depend on the type of phase change material used, the desired transition temperature, the type of boron nitride used, and similar considerations. The amount of phase change material in the phase change layer can be 1 to 99 volume percent (vol%), or 50 to 99 vol%, or 80 to 95 vol%, based on the total volume of the phase change layer. The amount of phase change material in the phase change layer can be at least 65 vol%, at least 70 vol%, at least 75 vol%, at least 80 vol%, at least 85 vol%, at least 90 vol%, or at least 95 vol%, and can be 99.9 vol% or less, 98 vol% or less, 97 vol% or less, or 95 vol% or less. The first and second capping layers can each independently comprise 0 to 5 vol%, or 0 to 1 vol% of phase change material based on the total volume of the phase change layer.

[0024] The phase-change layer, the first capping layer, and the second capping layer may each independently contain a binder. The phase-change layer may contain 0.5 to 15 vol%, or 1 to 6 vol%, of the binder, based on the total volume of the phase-change layer. The first capping layer and the second capping layer may each independently contain 10 to 100 vol%, or 30 to 70 vol%, or 30 to 50 vol%, of the binder, based on the total volume of each capping layer. The binder may include at least one of a thermoplastic polymer or a thermosetting polymer. The binder may include at least one of polystyrene, epoxy, polybutadiene, or polyisoprene.

[0025] Thermoplastic polymers include polyolefins (e.g., cyclic olefin polymers), fluoropolymers, polyacetals, poly(C 1~6 alkyl)acrylate, polyacrylamide, polyacrylonitrile, polyamide, polyamideimide, polyanhydride, polyarylene ether, polyarylene ether ketone, polyarylene ketone, polyarylene sulfide, polyarylene sulfone, polybenzothiazole, polybenzoxazole, polybenzimidazole, polycarbonate, polyester, polyetherimide, polyimide, poly(C1~6 The polymer may include at least one of a poly(alkyl)methacrylate), polymethacrylamide, polyoxadiazole, polyoxymethylene, polyphthalide, polysilazane, polysiloxane, polystyrene, polysulfide, polysulfonamide, polysulfonate, polythioester, polytriazine, polyurea, polyurethane, or vinyl polymer.

[0026] Thermoset polymers are derived from thermosetting monomers or prepolymers (resins) that can be irreversibly cured and become insoluble upon polymerization or curing, where curing can be induced by exposure to heat or radiation (e.g., ultraviolet, visible, infrared, or electron beam (e-beam) radiation). Thermosetting polymers include alkyds, bismaleimide polymers, bismaleimide triazine polymers, cyanate ester polymers, benzocyclobutene polymers, benzoxazine polymers, diallyl phthalate polymers, epoxies, hydroxymethylfuran polymers, melamine-formaldehyde polymers, phenolic resins (including phenol-formaldehyde polymers such as novolacs and resols), benzoxazines, polydienes such as polybutadiene (including homopolymers and copolymers thereof, e.g., poly(butadiene-isoprene)), polyisocyanates, polyureas, polyurethanes, triallyl cyanurate polymers, triallyl isocyanurate polymers, certain silicones, and polymerizable prepolymers (e.g., prepolymers having ethylenic unsaturation, such as unsaturated polyesters, polyimides). Prepolymers can be prepared, for example, from reactive monomers such as styrene, alpha-methylstyrene, vinyl toluene, chlorostyrene, acrylic acid, (meth)acrylic acid, (C 1~6 alkyl)acrylate, (C 1~6 The prepolymer may be polymerized, copolymerized, or crosslinked using alkyl (alkyl) methacrylate, acrylonitrile, vinyl acetate, allyl acetate, triallyl cyanurate, triallyl isocyanurate, or acrylamide. The weight average molecular weight of the prepolymer may be 400 to 10,000 daltons based on polystyrene standards.

[0027] The phase-change layer and, optionally, one or both of the first and second capping layers comprise a plurality of boron nitride particles. The plurality of boron nitride particles may comprise one or both of a single particle (primary particle) or an aggregate comprising a plurality of particles (secondary particle). The plurality of boron nitride particles (primary particle or aggregate of particles) may have an average particle size of 0.1 to 1,000 micrometers, or 5 to 500 micrometers, or 10 to 250 micrometers, or 25 to 150 micrometers, or 500 nanometers to 100 micrometers, or 3 to 40 micrometers. The plurality of boron nitride particles may comprise irregularly shaped hexagonal boron nitride platelets having an average particle size equal to or greater than 10 micrometers. "Particle size," as used herein, refers to the average diameter or equivalent diameter, best determined by standard laser particle measurement. Particle size is measured using a D, also known as the median diameter or the median value of a particle size distribution. 50 It can refer to particle size; it is the value of the particle size at 50% by mass in the cumulative distribution.

[0028] The plurality of boron nitride particles may be in the form of at least one of powder (including flakes, platelets, and other shapes), fibers, rods, whiskers, sheets, nanosheets, aggregates, or boron nitride nanotubes (BNNTs), and may vary in terms of crystal type, shape, and size, including distributions of the foregoing. The plurality of boron nitride particles may have an average aspect ratio (ratio of particle width or diameter to length) of 1:2 to 1:100,000, or 1:5 to 1:1,000, or 1:10 to 1:300. Exemplary particle shapes having particularly high aspect ratios include platelets, rod-like particles, fibers, whiskers, and the like. The plurality of boron nitride particles may include boron nitride platelets, e.g., hexagonal boron nitride in the form of platelets. The exact shape of the platelets is not critical. In this regard, the boron nitride platelets may have an irregular shape. It is noted that the term "platelet" as used herein generally describes any thin, flat particle, including flakes. The platelets can have an average aspect ratio (ratio of particle width to length) of 4:5 to 1:300, or 1:2 to 1:300, or 1:2 to 1:200, or 3:5 to 1:100, or 1:25 to 1:100.

[0029] In terms of crystal type, the boron nitride particles can include at least one structure that is hexagonal, cubic, wurtzite, rhombohedral, or other composite structure. Among various structures, boron nitride particles with a hexagonal structure (hBN) can achieve excellent thermal conductivity, for example, from 10 to over 300 W / mK, while particles with a cubic structure can achieve extremely high thermal conductivity of up to 1,300 W / mK. The thermal conductivity of boron nitride particles can be determined in accordance with ASTM E1225-13. Hexagonal boron nitride has a layered structure similar to graphite, with the layers stacked in a coordinated manner so that the hexagonal rings in the layers overlap. The positions of N and B atoms alternate from layer to layer. The boron nitride particles can have a hexagonal structure with a crystallization index of at least 0.12, or 0.20-0.55, or 0.30-0.55. Hexagonal boron nitride particles can be obtained from a variety of commercial sources.

[0030] Crystalline or partially crystalline boron nitride particles can be produced by methods known in the art. These include, for example, boron nitride powders produced from the pressing process disclosed in U.S. Patent Nos. 5,898,009 and 6,048,511, the boron nitride aggregate powder disclosed in U.S. Patent Application Publication No. 2005 / 0041373, and the highly exfoliated boron nitride powder disclosed in U.S. Patent No. 6,951,583. Various boron nitride powders are commercially available, for example, from Momentive under the trade name POLARTHERMA™ Boron Nitride.

[0031] The plurality of boron nitride particles can include a coating. The coating can include at least one of carbon, aluminum, silicon, germanium, copper, nickel, palladium, platinum, iridium, cobalt, iron, ruthenium, molybdenum, tungsten, tantalum, zirconium, or titanium, for example, in the form of at least one of a carbide, an oxide, a nitride, a sulfide, or a phosphide. The coating can include an inorganic carbide (such as aluminum carbide or titanium carbide), an inorganic oxide (such as aluminum oxide (Al2O3), magnesium oxide, silicon dioxide (SiO2), titanium dioxide, yttria oxide, zirconium oxide, or zinc oxide), an inorganic nitride (such as aluminum nitride (AlN) or silicon nitride), an inorganic sulfide (such as gallium sulfide, molybdenum sulfide, or tungsten sulfide), an inorganic hydroxide (aluminum hydroxide (Al x O y H z ), zinc hydroxide (Zn x O y H z ) or silicon hydroxide (Si x O y H z) or inorganic phosphides. The coating can include at least one of silicon dioxide or aluminum oxide. The coating can include one or more separate coating layers, which can optionally be alternating layers. The coating can be applied to the plurality of boron nitride particles by atomic layer deposition (ALD). ALD is a type of chemical vapor deposition in which a thin film is deposited on a substrate using gas-phase chemical precursors that react at the substrate surface.

[0032] The boron nitride particles can be surface treated with a coupling agent. The coupling agent promotes or participates in the formation of covalent bonds that improve adhesion between the filler and the thermosetting polymer matrix. Exemplary coupling agents include silanes, zirconates, titanates, and the like, such as vinyltrichlorosilane, vinyltrimethoxysilane, trivinylmethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β(aminoethyl)γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrieth ...

[0033] Examples of suitable silanes include bis(trimethoxysilylethyl)-γ-aminopropylmethyldimethoxysilane, bis(trimethoxysilylethyl)benzene, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, bis(triethoxysilyl)ethylene, triethoxysilyl-modified butadiene, styrylethyltrimethyloxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, trimethoxyphenylsilane, perfluorooctyltriethoxysilane, and γ-mercaptopropyltrimethoxysilane.

[0033] The phase-change layer may contain 5 to 95 vol%, or 50 to 90 vol%, of a plurality of boron nitride particles, based on the total volume of the phase-change layer. The first capping layer and the second capping layer may each independently contain 0 to 90 vol%, or 10 to 80 vol%, or 30 to 70 vol%, or 50 to 70 vol%, of a plurality of boron nitride particles, based on the volume of the respective capping layer. At least one of the capping layers may contain more than 0 to 90 vol%, or 30 to 70 vol%, or 50 to 70 vol%, of a plurality of boron nitride particles, based on the total volume of the respective capping layer.

[0034] The boron nitride particles in the phase change layer may be aligned, for example, the average angle of the boron nitride particles may be 0 to 45°, or 10 to 35°, where the angle, θ, is measured relative to the vertical (see FIG. 1).

[0035] The phase change layer, first capping layer, and second capping layer may each independently contain additional fillers other than boron nitride, for example, to adjust the dielectric properties of the layered phase change composite. Low coefficient of expansion fillers such as glass beads, silica, or crushed microglass fibers can be used. Thermally stable fibers such as aromatic polyamides or polyacrylonitrile can be used. Exemplary fillers include titanium dioxide (rutile and anatase), barium titanate, strontium titanate, fused amorphous silica, corundum, wollastonite, aramid fibers (e.g., KEVLAR® from DuPont), fiberglass, Ba2Ti9O 20 , quartz, aluminum nitride, silicon carbide, beryllia, alumina, magnesia, mica, talc, nanoclays, aluminosilicates (natural and synthetic), or fused silicon dioxide (e.g., CAB-O-SIL™ from Cabot Corporation), each of which may be used alone or in combination.

[0036] The additional filler may be in the form of solid, porous, or hollow particles. The particle size of the additional filler affects several important properties, including coefficient of thermal expansion, modulus of elasticity, elongation, and flame retardancy. The additional filler may have an average particle size of 0.1 to 15 micrometers, or 0.2 to 10 micrometers. Combinations of fillers with bimodal, trimodal, or higher average particle size distributions may be used. The filler may be present in an amount of 0.1 to 80 vol%, or 1 to 65 vol%, or 5 to 50 vol%, based on the total volume of each layer.

[0037] The phase-change layer, first capping layer, and second capping layer can each independently include at least one additive, such as a flame retardant, a cure initiator, a crosslinker, a viscosity modifier, a wetting agent, or an antioxidant. The particular choice of additive can depend on the polymer used, the particular application of the layered phase-change composite, or the desired properties for that application, and can be selected to enhance or not adversely affect electrical properties, such as thermal conductivity, dielectric constant, dissipation factor, dielectric loss, or other desired properties, when used in a circuit subassembly.

[0038] The flame retardant may be inorganic and may be present in particulate form. The inorganic flame retardant may include, for example, a metal hydrate having a volume average particle size of 1 to 500 nanometers (nm), or 1 to 200 nm, or 5 to 200 nm, or 10 to 200 nm; alternatively, the volume average particle size may be 500 nm to 15 micrometers, or 1 to 5 micrometers. The metal hydrate may include a hydrate of a metal, for example, at least one of Mg, Ca, Al, Fe, Zn, Ba, Cu, or Ni. Hydrates of Mg, Al, or Ca, such as aluminum hydroxide, magnesium hydroxide, calcium hydroxide, iron hydroxide, zinc hydroxide, copper hydroxide, nickel hydroxide, or calcium aluminate hydrate, gypsum dihydrate, zinc borate, or barium metaborate, may be used. Composites of these hydrates may also be used, for example, hydrates containing Mg and at least one of Ca, Al, Fe, Zn, Ba, Cu, or Ni. Complex metal hydrates have the formula MgM x (OH)y wherein M is Ca, Al, Fe, Zn, Ba, Cu, or Ni, x is 0.1 to 10, and y is 2 to 32. The flame retardant particles can be coated or otherwise treated to improve dispersion or other properties.

[0039] Organic flame retardants can be used as an alternative to or in addition to inorganic flame retardants. Examples of organic flame retardants include melamine cyanurate, fine particle size melamine polyphosphate, various other phosphorus-containing compounds such as aromatic phosphinates, diphosphinates, phosphonates, phosphates, polysilsesquioxanes, siloxanes, or halogen compounds such as hexachloroendomethylenetetrahydrophthalic acid (HET acid), tetrabromophthalic acid, or dibromoneopentyl glycol. Examples of brominated flame retardants include SAYTEX™ BT93W (ethylene bistetrabromophthalimide), SAYTEX™ 120 (tetradecabromodiphenoxybenzene), or SAYTEX™ 102 (decabromodiphenyl oxide), available from Albermarle Corporation. Flame retardants can be used in combination with synergists; for example, halogenated flame retardants can be used in combination with a synergist such as antimony trioxide, and phosphorus-containing flame retardants can be used in combination with a nitrogen-containing compound such as melamine.

[0040] The layered phase change composite can be formed by forming a first capping layer from a first composition, forming a phase change layer from the phase change composition including vibrating the phase change composition on a three-way vibration stage, and forming a second capping layer from a second composition. The steps of forming the first capping layer and the second capping layer each independently include vibrating the respective compositions on a three-way vibration stage. The step of forming the phase change layer can include heating the phase change composition to a temperature equal to or greater than the phase change temperature.

[0041] The phase-change composition may be solvent-free, for example, the phase-change composition may contain 0-0.5 wt % or 0 wt % solvent based on the total weight of the phase-change composition.

[0042] In an embodiment, the layered phase change composite can include a phase change layer including a phase change material, a plurality of boron nitride particles, and a binder; and a first capping layer, or both the first capping layer and the second capping layer, positioned on both sides of the phase change layer. The phase change layer can each include 1 to 99 vol% of the phase change material, 5 to 95 vol% of the plurality of boron nitride particles, and 0.5 to 15 vol% of the binder, based on the total volume of the phase change layer. The phase change material can have a transition temperature of -5 to 150°C. The phase change material can have a temperature of at least C 10~36 Alkane, C 10~35 fatty acids, C 10~35 The binder may include one of a fatty acid ester and a vegetable oil. The boron nitride particles may include a plurality of hexagonal boron nitride platelets. The binder may include at least one of polystyrene, epoxy, polybutadiene, or polyisoprene. The phase-change layer may have a thickness of 0.05 to 10 mm, or 0.5 to 2 mm, or 0.5 to 1.5 mm, and each of the capping layers may independently have a thickness of 0.001 to 1 mm, or 0.01 to 0.5 mm. The first capping layer and the second capping layer each independently include 10 to 100 vol% of a binder, e.g., epoxy, and optionally a plurality of hexagonal boron nitride platelets, based on the total volume of the respective capping layer.

[0043] The layered phase change composite can be formed by forming a first capping layer from a first composition comprising a polymer and optionally a plurality of boron nitride particles; casting a curable composition comprising a phase change material and a first plurality of boron nitride particles onto a three-way vibration stage, vibrating the stage in three directions, and curing the curable composition curing agent to form a phase change layer; and forming a second capping layer on the phase change layer from a second composition comprising a second polymer and optionally a second plurality of boron nitride particles.

[0044] The layered phase change composite can be formed by: casting a first curable composition containing a first solvent and optionally a plurality of boron nitride particles onto a three-way vibration stage, evaporating the first solvent while vibrating the stage in three directions, and curing the first curable composition to form a first capping layer; casting a curable composition containing a phase change material and a first plurality of boron nitride particles onto a three-way vibration stage, vibrating the stage in three directions, and curing the curable composition to form a phase change layer; and casting a second curable composition containing a second solvent and optionally a second plurality of boron nitride particles onto the three-way vibration stage, evaporating the second solvent while vibrating the stage in three directions, and curing the second curable composition to form a second capping layer. The first curable composition can include a first epoxy and a first curing agent. The second curable composition can include a second epoxy and a second curing agent. The phase change composition can include a binder. It is noted that the steps of forming the first and second capping layers can be performed independently, particularly without vibration, in cases where they do not include a plurality of boron nitride particles.

[0045] The first and second curable compositions can each independently contain 3 to 50% by weight of a first solvent and a second solvent, respectively, based on the total weight of the respective compositions. The first and second solvents can independently include at least one of methanol, ethanol, isopropanol, butanol, xylene, toluene, methyl ethyl ketone, methyl isobutyl ketone, hexane, heptane, octane, nonane, cyclohexane, isophorone, or a terpene-based solvent. The first and second capping compositions can each independently contain 3 to 50% by weight of a solvent, based on the total weight of the respective capping compositions.

[0046] The composite layers can be formed in a layer-by-layer manner, where a first capping layer is formed, a phase-change layer is formed on the first capping layer, and a second capping layer is formed on the phase-change layer. For example, forming the phase-change layer can include casting a curable composition on the first capping layer, and forming the second capping layer can include casting the second curable composition on the phase-change layer. Conversely, forming the composite layers can include forming a layered stack of a first capping layer, a phase-change layer, and a second capping layer, and then laminating the layered stack.

[0047] If vibration is used, the vibration can include vibrating the respective compositions until a gel point is reached. The vibration can include vibration in the z-direction at a frequency of 60 Hertz (Hz), with vibration noise predominantly in the z-axis and in the x- and y-directions.

[0048] Each layer can be formed by spraying, air atomized spraying, airless atomized spraying, electrostatic coating, slot die coating, contact slot coating, curtain coating, knife coating, roll coating, kiss coating, transfer coating, brushing, screen printing, padding, dipping, saturating, printing, pressure or gravity fed nozzles / guns, hot melt applicators, molding, overmolding, injection molding, reaction injection molding, pultrusion, extrusion, plasma coating, or using resin infusion techniques (e.g., resin transfer molding (RTM)), vacuum infusion (VIP), or vacuum assisted RTM (VARTM).

[0049] The first capping layer and the second capping layer can each be independently formed by casting onto a carrier that is subsequently released, or alternatively onto a conductive metal layer that can subsequently be formed into a layer of the circuit structure.

[0050] After each layer is independently formed, the solvent, if present, can be evaporated. After each layer is independently formed, it can be at least partially cured (B-staged), as appropriate, or the layer can be fully cured. Each layer can be independently first partially cured and then fully cured in a layered stack to promote adhesion between each layer. Each layer can be independently heated, for example, at 20-200°C, or 30-150°C, or 40-100°C.

[0051] The layered phase-change composite can optionally include one or more additional layers. For example, one or more additional phase-change layers can optionally be present with an additional capping layer. The composition can include, for example, an adhesive layer positioned between the phase-change layer and the capping layer. Conversely, the phase-change layer can be in direct physical contact with one or both of the first and second capping layers.

[0052] Layered phase change composites can provide devices with improved thermal stability, resulting in the ability to avoid degradation of the performance and service life of electronic devices. The combination of boron nitride particles and phase change material can be advantageous for use as a thermal management material, particularly in electronics, where the presence of the phase change material can enable a combination of high latent heat capacity and energy absorption, and the presence of boron nitride can increase the rate of heat transfer in and out of the phase change layer, thereby improving thermal management and reducing heat buildup, reducing problems, and allowing for faster processor speeds.

[0053] The article can include a layered phase change composite. The layered phase change composite can be used in a variety of applications, including electronic devices, LED devices, or batteries. The layered phase change composite can be used in a wide variety of electronic and other devices that generate heat and damage the performance of processors and other operating circuits (memory, video chips, or telecom chips). Examples of such electronic devices include mobile phones, personal digital assistants (PDAs), smartphones, tablets, laptop computers, portable scanners, or other common portable devices. The layered phase change composite can be incorporated into virtually any electronic device that requires cooling during operation, such as electronics used in consumer products, medical devices, automotive parts, aircraft parts, radar systems, guidance systems, or global positioning systems. The layered phase change composite can be used in batteries, engine control units (ECUs), airbag modules, temperature controllers, door modules, cruise control modules, instrument panels, climate control modules, anti-lock brake modules (ABS), power transmission controllers, or power distribution modules. Layered phase change composites and articles thereof can also be incorporated into the packaging of electronics or other structural components. Generally, devices that rely on the performance characteristics of electronic processors or other electronic circuits can benefit from increased or more stable performance characteristics resulting from the use of aspects of the layered phase change composites. In some embodiments, the article is a thermal management material, a thermal pad, an energy storage electrode, a supercapacitor, a fuel cell, a battery, a capacitive desalination device, an acoustic insulator, a thermal insulation composite, a chemical sensor, a mechanical sensor, a biomedical device, an actuator, an adsorbent, a catalyst support, a field emission device, a mechanical wetting device, a filter, a three-dimensional flexible electronic component, a circuit material, an integrated circuit package, a printed circuit board, an electronic device, a cosmetic composition, wearable electronics, a high-efficiency flexible electronic device, a power electronic device, a high-frequency device, or an energy storage device.

[0054] Layered phase change composites can be incorporated into virtually any electronic device that requires cooling during operation. For example, electronics used in automobile parts, aircraft parts, radar systems, guidance systems, and GPS devices incorporated into civilian and military equipment and other vehicles can benefit from layered phase change composites in engine control units (ECUs), airbag modules, body controls, door modules, cruise control modules, instrument panels, climate control modules, anti-lock braking modules (ABS), power transmission controls, or power distribution modules. Layered phase change composites and articles containing the composites can also be incorporated into the exterior of electronics or other structural components. In general, any device that relies on the performance characteristics of an electronic processor or other electronic circuitry can benefit from increased or more stable performance characteristics resulting from the use of embodiments of the composites disclosed herein.

[0055] The following examples are provided to illustrate the present disclosure. The examples are merely illustrative and are not intended to limit devices made in accordance with the disclosure to the materials, conditions, or process parameters set forth herein. [Example]

[0056] Example 1 The first capping layer was prepared by casting a composition containing 20% ​​by weight isopropanol, 48% by weight boron nitride particles, and 32% by weight curable epoxy into a 3.3 centimeter diameter dish. The dish was then vibrated in the x, y, and z directions while the solvent evaporated. After the solvent evaporated, the epoxy was cured to form the first capping layer. Vibration was stopped when the composition reached its gel point.

[0057] A phase change composition was then cast onto the first capping layer. The phase change composition contained 90% by weight paraffin and 10% by weight of a mixture of boron nitride and epoxy. The phase change composition was vibrated in the x, y, and z directions to cure the epoxy and form a phase change layer. Figure 2 shows a top-down microscope image of the cured phase change layer. Figure 2 shows regions 12 of boron nitride particles formed in the phase change layer.

[0058] A second composition was then cast onto the phase-change layer. The second composition contained 20% by weight isopropanol, 48% by weight boron nitride particles, and 32% by weight curable epoxy. The dish was vibrated in the x, y, and z directions while the solvent evaporated. After the solvent evaporated, the epoxy was cured to form the second capping layer. The vibration was stopped when the composition reached its gel point. The layered phase-change composite was then dried at room temperature (approximately 20-25°C) for 2 hours.

[0059] Figure 3 is a scanning electron microscope image of a cross section of a layered phase change composite, illustrating the excellent alignment of the boron nitride particles in the phase change layer in the direction perpendicular to the broad surface of the composite.

[0060] Non-limiting aspects of the present disclosure are set forth below.

[0061] Aspect 1: A layered phase change composite comprising: a phase change layer comprising a phase change material, a plurality of boron nitride particles, and a binder; and a first capping layer and a second capping layer positioned on either side of the phase change layer.

[0062] Aspect 2: The phase change material is C 10~36 Alkane, C 10~35 fatty acids, C 10~35 10. The composite of embodiment 1, comprising at least one of a fatty acid ester or a vegetable oil.

[0063] Embodiment 3: The composite of embodiment 1 or 2, wherein the phase-change layer comprises 1 to 99 vol%, or 50 to 99 vol%, or 80 to 95 vol% of the phase-change material, based on the total volume of the phase-change layer.

[0064] Embodiment 4: The composite of any one of embodiments 1 to 3, wherein the phase change material has a transition temperature in the range of -5 to 150°C.

[0065] Embodiment 5: The composite of any one of embodiments 1 to 4, wherein the plurality of boron nitride particles comprises a plurality of hexagonal boron nitride platelets.

[0066] Embodiment 6: The layered phase change composite of any one of embodiments 1 to 5, wherein the phase change layer comprises 5 to 95 vol. %, or 50 to 90 vol. %, of a plurality of boron nitride particles, based on the total volume of the phase change layer.

[0067] Aspect 7: The layered phase change composite of any one of Aspects 1 to 6, wherein the binder comprises at least one of polystyrene, epoxy, polybutadiene, or polyisoprene.

[0068] Embodiment 8: The layered phase change composite of any one of embodiments 1 to 7, wherein the phase change layer comprises 0.5 to 15 vol. %, or 1 to 6 vol. %, of a binder based on the total volume of the phase change layer.

[0069] Embodiment 9: The layered phase change composite of any one of Embodiments 1 to 8, wherein the phase change layer has a thickness of 0.05 to 10, or 0.5 to 2, or 0.5 to 1.5 mm.

[0070] Embodiment 10: The layered phase change composite of any one of embodiments 1 to 9, wherein the first capping layer and the second capping layer comprise epoxy.

[0071] Embodiment 11: The layered phase change composite of any one of embodiments 1 to 10, wherein the first capping layer and the second capping layer each independently comprise 10 to 100 vol%, or 30 to 70 vol%, or 30 to 50 vol% of a binder relative to the total volume of the respective capping layer.

[0072] Example 12: The layered phase change composite of any one of Examples 1 to 11, wherein at least one of the first capping layer and the second capping layer comprises a plurality of boron nitride particles.

[0073] Aspect 13: The layered phase change composite of any one of Aspects 1 to 12, wherein at least one of the capping layers comprises 0 to 90 vol%, or 30 to 70 vol%, or 50 to 70 vol% of a plurality of boron nitride particles relative to the total volume of the respective capping layer.

[0074] Embodiment 14: The layered phase change composite of any one of embodiments 1 to 13, wherein each of the capping layers independently has a layer thickness of 0.001 to 1 mm, or 0.01 to 0.5 mm.

[0075] Embodiment 15: The layered phase change composite of any one of embodiments 1 to 14, having a heat of fusion of at least 50 J / g, or at least 75 J / g, or at least 100 J / g, or at least 50-150 J / g, as measured using thermogravimetric analysis.

[0076] Aspect 16: The layered phase change composite of any one of Aspects 1 to 15, having a thermal conductivity greater than 0.5 W / mK, or between 0.5 and 1 W / mK, as measured in accordance with ASTM D5470-17.

[0077] Embodiment 17: The layered phase change composite of any one of embodiments 1 to 16, further comprising a flame retardant.

[0078] Embodiment 18: An article comprising the layered phase change composite of any one of embodiments 1 to 17.

[0079] Aspect 19: The article of aspect 18, which is a thermal management material, a thermal pad, an electrode for energy storage, a supercapacitor, a fuel cell, a battery, a capacitive desalination device, an acoustic insulator, a thermal insulation composite, a chemical sensor, a mechanical sensor, a biomedical device, an actuator, an adsorbent, a catalyst support, a field emission device, a mechanical wetting device, a filter, a three-dimensional flexible electronic component, a circuit material, an integrated circuit package, a printed circuit board, an electronic device, a cosmetic composition, wearable electronics, a highly efficient flexible electronic device, a power electronics device, a high frequency device, or an energy storage device.

[0080] Embodiment 20: A method for producing a layered phase change composite described in any one of embodiments 1 to 17, comprising: forming a first capping layer from a first composition, optionally including a step of vibrating the first composition on a three-way vibration stage; forming a phase change layer from the phase change composition, optionally including a step of vibrating the phase change composition on a three-way vibration stage; and forming a second capping layer from the second composition, optionally including a step of vibrating the second composition on a three-way vibration stage; wherein each layer is formed independently and then laminated together to form the composite, and / or at least one of the layers is formed directly on one of the other layers.

[0081] Embodiment 21: The method of embodiment 20, wherein the phase-change composition does not include a solvent.

[0082] Aspect 22: The step of forming a first capping layer includes the steps of: casting a first composition comprising a first curable composition (e.g., comprising a first epoxy and a first curing agent), a first solvent, and a first plurality of boron nitride particles onto a three-way vibration stage; evaporating the first solvent while vibrating the stage in three directions; and curing the first curable composition to form the first capping layer; and the step of forming a phase-change layer includes the steps of casting a first composition comprising a phase-change material, a curable composition (e.g., comprising an epoxy and a curing agent), and a first plurality of boron nitride particles onto a three-way vibration stage; evaporating the first solvent while vibrating the stage in three directions; and curing the first curable composition to form the first capping layer. 21. The method of embodiment 20, comprising: casting a second composition onto a vibrating stage, vibrating the stage in three directions, and curing the curable composition to form a phase-change layer; wherein forming the second capping layer comprises casting a second composition onto the three-way vibrating stage, the second composition comprising a second curable composition (e.g., comprising a second epoxy and a second curing agent), a second solvent, and a second plurality of boron nitride particles, evaporating the second solvent while vibrating the stage in three directions, and curing the second curable composition to form the second capping layer.

[0083] Embodiment 23: The method of embodiment 22, wherein the step of casting the phase-change composition comprises casting the phase-change composition onto a first capping layer.

[0084] Embodiment 24: The method of embodiment 22 or 23, wherein casting the second composition comprises casting the second composition onto the phase-change layer.

[0085] Embodiment 25: The method of any one of embodiments 22 to 24, wherein each of the casting steps independently comprises vibrating the respective composition until a gel point is reached.

[0086] Example 26: The method of example 20 or 21, further comprising stacking the first capping layer, the phase-change layer, and the second capping layer to form a layered stack, and laminating the layered stack.

[0087] Aspect 27: The method of any one of aspects 20 to 26, wherein each of the first composition and the second composition independently comprises 3 to 50% by weight of the first solvent and the second solvent, respectively, relative to the total weight of the respective composition.

[0088] Aspect 28:C 10~36 Alkane, C 10~35 fatty acids, C 10~3517. The layered phase change composite of any one of aspects 1 to 16, comprising: a phase change layer comprising: a phase change material comprising at least one of a fatty acid ester or a vegetable oil; 5 to 95 vol. % of a plurality of boron nitride particles comprising a plurality of hexagonal boron nitride platelets; and 0.5 to 15 vol. % of a binder comprising at least one of polystyrene, epoxy, polybutadiene, or polyisoprene; and first and second capping layers positioned on opposite sides of the phase change layer. The phase change layer may have a thickness of 0.05 to 10 mm, or 0.5 to 2 mm, or 0.5 to 1.5 mm, and each of the capping layers may independently have a thickness of 0.001 to 1 mm, or 0.01 to 0.5 mm. The first and second capping layers may each independently comprise 10 to 100 vol. % of the binder, based on the total volume of the respective capping layers.

[0089] The compositions, methods, and articles can alternatively comprise, consist of, or consist essentially of any suitable material, step, or component disclosed herein. The compositions, methods, and articles can also, or alternatively, be formulated to be devoid of, or substantially free of, any material (or species), step, or component that is not otherwise necessary to achieve the function or purpose of the compositions, methods, and articles.

[0090] As used herein, the terms "a," "an," "the," and "at least one" do not denote limitations of quantity and are intended to cover both the singular and the plural, unless the context clearly dictates otherwise. For example, "an element" has the same meaning as "at least one element," unless the context clearly dictates otherwise. The term "combination" is inclusive of blends, mixtures, alloys, reaction products, and the like. Also, "at least one of" means that a list includes each element individually, as well as combinations of two or more elements of the list, and combinations of at least one element of the list with similar elements not specified.

[0091] The term "or" means "and / or" unless the context clearly dictates otherwise. References throughout this specification to "an embodiment," "another embodiment," "some embodiments," etc. mean that a particular element (e.g., a feature, structure, step, or characteristic) described in connection with an embodiment is included in at least one embodiment described herein and may or may not be present in other embodiments. Further, it should be understood that the described elements may be combined in any suitable manner in the various embodiments.

[0092] Unless otherwise specified herein, all test standards are the most recent valid standards as of the filing date of this application, or, if priority is claimed, the filing date of the first priority application in which the test standard is published. Endpoints of all ranges covering the same component or property are inclusive, independently combinable, and include all intermediate points and ranges. For example, a range of "up to 25 volume percent or 5 to 20 volume percent" includes the endpoints and all intermediate values ​​of the range, such as "5 to 25 volume percent," e.g., 10 to 23 volume percent, etc. The terms "first," "second," etc., as used herein, do not denote order, quantity, or importance, but rather are used to distinguish elements from one another. When an element, such as a layer, film, region, or substrate, is referred to as being "on" another element, it may be directly on the other element, or intervening elements may be present. In contrast, when an element is referred to as being "directly on" or "in direct physical contact with" another element, no intervening elements are present.

[0093] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs.

[0094] All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, if a term in this application conflicts or contradicts a term in the incorporated reference, the term from this application takes precedence over the conflicting term from the incorporated reference.

[0095] While particular embodiments have been described, presently unforeseen or unforeseeable alternatives, modifications, variations, improvements, and substantial equivalents may occur to applicant or those skilled in the art. Accordingly, the appended claims, as filed and as they may be amended, are intended to embrace all such alternatives, modifications, variations, improvements, and substantial equivalents. [Explanation of symbols]

[0096] 10 First Capping Layer 12 first plurality of boron nitride particles 14 First Polymer 20 Second Capping Layer 22 second plurality of boron nitride particles 24 Second Polymer 50 Phase change layer 52 Multiple boron nitride particles 54 Phase change materials

Claims

1. a phase change layer comprising a phase change material, a plurality of boron nitride particles, and a binder; and a first capping layer and a second capping layer positioned on either side of the phase change layer; A layered phase change composite comprising: A layered phase change composite, wherein the boron nitride particles in the phase change layer are aligned at an average angle of 0 to 45 degrees measured relative to a normal to the broad surface of the phase change layer.

2. the plurality of boron nitride particles comprises boron nitride platelets having an average aspect ratio of 4:5 to 1:300; 10. The layered phase change composite of claim 1, wherein the boron nitride platelets in the phase change layer are aligned at an average angle of 0 to 45 degrees measured relative to a normal to the broad surface of the phase change layer.

3. The phase change material is C 10～36 Alkane, C 10～35 fatty acids, C 10～35 3. The layered phase change composite of claim 1 or 2, comprising at least one of a fatty acid ester or a vegetable oil.

4. The phase change layer comprises 1 to 99 volume percent of the phase change material based on the total volume of the phase change layer.

4. The layered phase change composite of claim 1 .

5. 5. The layered phase change composite of claim 1, wherein the phase change material has a transition temperature of from -5 to 150 degrees Celsius.

6. 6. The layered phase change composite of claim 1, wherein at least one of the plurality of boron nitride particles comprises a plurality of hexagonal boron nitride platelets; or the binder comprises at least one of polystyrene, epoxy, polybutadiene, or polyisoprene.

7. the phase-change layer comprising 5 to 95 volume percent of a plurality of boron nitride particles based on the total volume of the phase-change layer; 7. The layered phase change composite of claim 1, wherein the boron nitride particles in the phase change layer are aligned at an average angle of 0 to 35 degrees measured relative to a normal to the broad surface of the phase change layer.

8. 8. The layered phase change composite of claim 1, wherein the phase change layer comprises 0.5 to 15 volume percent of binder, based on the total volume of the phase change layer.

9. 9. The layered phase change composite of claim 1, wherein the phase change layer has a thickness of 0.05 to 10 mm; and each of the capping layers independently has a thickness of 0.001 to 1 mm.

10. 10. The layered phase change composite of claim 1, wherein the first capping layer and the second capping layer comprise an epoxy.

11. 11. The layered phase change composite of claim 1, wherein the first capping layer and the second capping layer each independently comprise 10 to 100 volume percent of a binder, based on the total volume of the respective capping layer; and 0 to 90 volume percent of a plurality of boron nitride particles, based on the total volume of the respective capping layer.

12. 12. The layered phase change composite of claim 1, having at least one heat of fusion of at least 50 J / g as measured using thermogravimetric analysis or a thermal conductivity of greater than 0.5 watts per meter Kelvin as measured in accordance with ASTM D5470-17.

13. 13. An article comprising the layered phase change composite article of any one of claims 1 to 12, the article being a thermal management material, a thermal pad, an energy storage electrode, a supercapacitor, a fuel cell, a battery, a capacitive desalination device, an acoustic insulator, a thermal insulation composite, a chemical sensor, a mechanical sensor, a biomedical device, an actuator, an adsorbent, a catalyst support, a field emission device, a mechanical wetting device, a filter, a three-dimensional flexible electronic component, a circuit material, an integrated circuit package, a printed circuit board, an electronic device, a cosmetic composition, wearable electronics, a highly efficient flexible electronic device, a power electronic device, a high frequency device, or an energy storage device.

14. 13. A method for producing a layered phase change composite according to any one of claims 1 to 12, comprising the steps of: forming a first capping layer from the first composition, optionally including vibrating the first composition on a three-way vibration stage; forming a phase-change layer from the phase-change composition, the phase-change composition comprising vibrating the phase-change composition on a three-way vibration stage; and forming a second capping layer from the second composition, optionally including vibrating the second composition on a three-way vibration stage; Including, A method wherein each layer is formed independently and then laminated together to form a composite, and / or at least one of the layers is formed directly onto one of the other layers.

15. The method of claim 14 , wherein the phase-change composition is solvent-free.

16. The step of forming the first capping layer includes the steps of: casting a first composition comprising a first curable composition (e.g., a composition comprising a first epoxy and a first curing agent), a first solvent, and a first plurality of boron nitride particles onto a three-way vibration stage; evaporating the first solvent while vibrating the stage in three directions; and curing the first curable composition to form the first capping layer; forming the phase change layer includes casting a phase change composition including a phase change material, a curable composition (e.g., a composition including an epoxy and a curing agent), and a plurality of boron nitride particles onto a three-way vibration stage, vibrating the stage in three directions, and curing the curable composition to form the phase change layer; 15. The method of claim 14, wherein the step of forming the second capping layer comprises: casting a second composition comprising a second curable composition (e.g., a composition comprising a second epoxy and a second curing agent), a second solvent, and a second plurality of boron nitride particles onto a three-way vibration stage; evaporating the second solvent while vibrating the stage in three directions; and curing the second curable composition to form the second capping layer.

17. 17. The method of claim 16, wherein casting the phase change composition comprises casting the phase change composition onto the first capping layer.

18. 18. The method of claim 16 or 17, wherein casting the second composition comprises casting the second composition onto the phase-change layer.

19. 19. The method of any one of claims 16 to 18, wherein each of the casting steps independently comprises vibrating the respective composition until a gel point is reached.

20. 17. The method of claim 14, further comprising stacking the first capping layer, the phase-change layer, and the second capping layer to form a layered stack and laminating the layered stack.

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