Thermal interface material

Abstract

The thermally conductive composition includes a blocked isocyanate prepolymer composition containing an isocyanate prepolymer blocked with one or more of an alkyl phenol or an alkenyl phenol, an amine composition containing one or more polyether amines and one or more catalysts selected from the group consisting of carboxylate salts, tertiary amines, amidines, guanidines, and diazabicyclo compounds, and a thermally conductive filler present in a range of 60 wt% to 98 wt% in weight percent (wt%) of the thermally conductive composition, the thermally conductive composition curing at a temperature in the range of 18° C. to 35° C. when the blocked isocyanate prepolymer composition and the amine composition are mixed. The method includes preparing a thermally conductive gap filler prepared by combining the blocked isocyanate prepolymer composition and the amine composition, and curing the resulting thermally conductive composition, such as at room temperature.

Description

[Technical field]

[0001] The present disclosure relates to thermally conductive compositions for use as gap fillers, adhesives, sealants, or pastes in applications requiring thermal management, such as electronics and automotive applications, and methods for their use. [Background technology]

[0002] Introduction Thermal interface materials such as gap fillers, adhesives, and gels are widely used for thermal management in electronics and automotive applications. For example, electric vehicle (EV) batteries are cooled by a cooling plate with circulating fluid underneath its battery module. For efficient cooling, good thermal contact between the battery module and the cooling plate is required. Gap fillers fill this gap and provide thermal contact between the battery module and the cooling plate. Thermal gap pads and dispensable gap fillers are two of the main gap filler technologies. Of the two, dispensable gap fillers have the advantage of providing more efficient heat transfer and less waste of material compared to thermal pads. It is desirable to have a thermal interface material composition that has high thermal conductivity (>0.5 W / m·K), the ability to form a hardened solid part without the application of heat, low density, and is easily processed.

[0003] However, there are some significant issues with currently available thermal interface materials. For example, polyurethane (PU) thermal interface formulations based on isocyanate monomers, or isocyanate prepolymers with residual isocyanate monomers, and / or polymeric isocyanates with residual isocyanate monomers, present concerns regarding the handling of materials containing isocyanates. Some material users even impose requirements of less than 0.1 wt. % free isocyanate monomer (e.g., free toluene diisocyanate (TDI), methylene diphenyl diisocyanate (MDI), etc.). These regulations regarding the free isocyanate monomer content of PU formulations exist to comply with (among other things) European Union regulations.

[0004] Other issues with PU-based thermal management products include stabilization of isocyanate functional groups, which may have limited storage stability (i.e., shorter shelf life as indicated by increased viscosity) that may be exacerbated / shortened in the presence of fillers. Low cost, low density thermally conductive fillers such as aluminum trihydrate are not compatible with isocyanates due to the presence of surface hydroxyl groups that can react with available isocyanate groups, rendering such formulations unstable and unusable. Summary of the Invention

[0005] In one embodiment, a thermally conductive composition includes a blocked isocyanate prepolymer composition containing an isocyanate prepolymer blocked with one or more alkylphenols or alkenylphenols, an amine composition containing one or more polyetheramines and one or more catalysts selected from the group consisting of carboxylate salts, tertiary amines, amidines, guanidines, and diazabicyclo compounds, and a thermally conductive filler present in a weight percent (wt%) range of 60 wt% to 98 wt%, wherein the thermally conductive composition cures at a temperature in the range of 18° C. to 35° C. when the blocked isocyanate prepolymer composition and the amine composition are mixed.

[0006] In another aspect, the method includes preparing a thermally conductive gap filler prepared by combining a blocked isocyanate prepolymer composition with an amine composition, and curing the resulting thermally conductive composition, such as at room temperature.

[0007] In another aspect, a method includes preparing a thermally conductive composition by combining a blocked isocyanate prepolymer composition with an amine composition, and installing the thermally conductive composition between a heat source and a heat sink in an EV battery. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The embodiments disclosed herein relate to thermally conductive compositions for use in thermal management applications, including improving heat transfer in batteries, electronic devices, automotive applications, and the like. The thermally conductive compositions are formulated as two-component mixtures that are combined and cured in situ at room temperature to form a thermally conductive gap filler. In some cases, the thermally conductive composition may be pre-cured and applied as a gap filler pad. The two-component system may include a blocked isocyanate prepolymer composition and an amine composition that are stabilized and exhibit minimal viscosity or squeeze force increase until combined for use. The compositions disclosed herein may also include a dispersion additive in one or more of the system components.

[0009] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs, and all publications, patent applications, patents, and other references mentioned herein are incorporated by reference.

[0010] Numerical ranges disclosed herein include all values ​​between and including the lower and upper limits. Ranges including explicit values ​​(e.g., 1 or 2, or 3-5, or 6, or 7) include any subranges between any two explicit values ​​(e.g., 1-2, 2-6, 5-7, 3-7, 5-6, etc.). Unless stated to the contrary, implicit from the context, or customary in the art, all parts and percentages are by weight and all testing methods are current as of the filing date of this disclosure.

[0011] As disclosed herein, the terms "composition", "formulation", or "mixture" refer to a physical blend of different components obtained by mixing the components by physical means in parts by weight. The sum of the weight percentages of each component in a composition is 100% by weight, based on the total weight of the composition.

[0012] As used herein, the term "average particle size" refers to the median particle size or diameter of a distribution of particles, as determined, for example, by a Multisizer 3 Coulter Counter (Beckman Coulter, Inc., Fullerton, Calif.) according to the procedure recommended by the manufacturer. This is the volume average particle size. Median particle size D 50 is defined as the size at which 50% of the particles in a distribution are smaller than the median diameter and 50 cumulative % of the particles in a distribution are larger than the median diameter. D 90 is defined as the size at which 90 cumulative % of the particles in a distribution are smaller than a specified value. 10is defined as the size at which 10 cumulative percent of the particles in the distribution are smaller than a specified value. The average particle size may be estimated based on measuring the surface area according to 8-11 ASTM D4315, or by using sieves of various mesh sizes to calculate the average from the cumulative weight of each particle group. These alternative methods give estimates of the average particle size similar to those determined by laser diffraction methods. The span of a filler particle size distribution is defined as (D 90 -D 10 ) / D 50 It is defined as the width of the particle size distribution.

[0013] As disclosed herein, "and / or" means "and, or alternatively." All ranges are inclusive of the endpoints unless otherwise indicated.

[0014] As disclosed herein, "room temperature" means a temperature range of 18°C ​​to 35°C.

[0015] As disclosed herein, "cure" and "cured" refer to the increase in viscosity or squeezing force after mixing, with the eventual hardening of the material and the formation of solid parts resulting from crosslinking of polymer chains.

[0016] As disclosed herein, "molecular weight" means number average molecular weight.

[0017] As disclosed herein, "thermally conductive filler" means a thermal conductivity value of greater than 1 W / m·K as measured by ISO 22007-2 using a hot disk.

[0018] As disclosed herein, "thermally conductive composition" (including both cured and uncured compositions) means a composition having a thermal conductivity value of greater than 0.5 W / m·K as measured by ISO 22007-2 using a hot disk.

[0019] As disclosed herein, "squeeze force" refers to the resistance of a thermally conductive composition or component to compression measured in Newtons. Squeeze force is measured using a TA.XTplus texture analyzer equipped with a 50 kg load cell. After each sample is dispensed onto a flat aluminum substrate, an acrylic probe with a diameter of 40 mm is lowered to pinch the test material against the flat substrate to achieve a standard gap thickness of 5.0 mm. Any excess overflow material is cut off with a flat edge spatula. After cutting, the test is started and the probe is moved at a rate of 1.0 mm / sec to a final thickness of 0.3 mm while recording the force. The specific force value recorded at a gap of 0.5 mm is reported as "squeeze force".

[0020] Viscosity can be measured using a TA instruments ARES-G2, AR2000 model rheometer or an Anton Paar MCR rheometer using a parallel plate fixture using methods commonly known in the art.

[0021] Embodiments relate to thermally conductive compositions for use in thermal management applications, including improving heat transfer in electronic devices, batteries, automotive applications, etc. The compositions described can be used as thermally conductive gap fillers or pre-cured thermal pads for applications requiring thermal management, such as electric vehicle batteries.

[0022] The thermally conductive compositions disclosed herein generally comprise the product obtained from combining a blocked isocyanate prepolymer composition ("A-side") and an amine composition ("B-side"), which are two-component curable compositions. During application, the A-side and B-side are mixed to initiate a curing reaction between the blocked isocyanate prepolymer and the amine functional groups at room temperature to form the thermally conductive composition. The thermally conductive composition may also include one or more thermally conductive fillers in the A-side and B-side to enhance heat transport properties.

[0023] The blocked isocyanate prepolymer composition includes an isocyanate prepolymer that is reacted with a blocking agent to limit the presence of free isocyanate (e.g., below a concentration of 0.1 wt%) and minimize premature gelation and crosslinking of the prepolymer. Reducing the free isocyanate concentration also improves storage, safety, and handling properties. In addition to the safety benefits, blocking the isocyanate functionality of the prepolymer also increases the compatibility of the blocked isocyanate prepolymer composition with fillers, including thermally conductive fillers. In some cases, fillers may be added in weight percent (wt%) up to 60 wt% or more on the A-side and / or B-side of the thermally conductive composition. The thermally conductive compositions disclosed herein are also compatible with low density and low cost fillers, such as aluminum trihydrate.

[0024] Thermally conductive compositions can be prepared by mixing the blocked isocyanate prepolymer composition with the amine composition at room temperature to produce a cured solid at room temperature. Room temperature curing represents an improvement over typical blocked isocyanate formulations, which are often cured at temperatures of 80°C or higher. The ability to produce thermally conductive compositions cured at room temperature increases the applicability of the material to heat-sensitive applications such as electric vehicle batteries and provides the added benefit of reduced energy consumption during fabrication.

[0025] The present disclosure is also directed to methods of making and using the thermally conductive composition. The thermally conductive composition can be prepared by combining a blocked isocyanate prepolymer composition with an amine composition, where at least one of the blocked isocyanate prepolymer composition or the amine composition includes a thermally conductive filler. The filler and the thermally conductive filler may also be treated to increase surface hydrophobicity and storage stability, while also reducing premature viscosity buildup. The thermally conductive composition may also include one or more additives, such as dispersing additives or plasticizers, that reduce the viscosity or squeezing force of the thermally conductive composition. Reducing the viscosity and squeezing force of the components of the thermally conductive composition may be beneficial, for example, by reducing the force required to assemble the gap filler between a heat source and a heat sink, such as in EV battery applications. The reduced force in the system reduces the possibility of damaging battery module components, increasing reproducibility and safety. In particular, the use of a blocked isocyanate prepolymer composition reduces concerns of free isocyanate monomer or volatile silicone while maintaining high thermal conductivity.

[0026] The blocked isocyanate prepolymer compositions described herein may be blocked with one or more blocking agents, including alkylphenol and / or alkenylphenol blocking agents. The blocked isocyanate prepolymer compositions and / or amine compositions may also contain one or more functional additives, including moisture scavengers, plasticizers, adhesion promoters, thixotropic agents, catalysts, colorants, antioxidants, wetting agents, filler treatments, surface treatment additives, or combinations thereof. A catalyst may be mixed into the B side of the two-part curable composition. The two-part curable compositions disclosed herein, in some embodiments, may be cured to form a thermally conductive gap filler or gap pad.

[0027] A.) Blocked Isocyanate Prepolymer Composition The blocked isocyanate prepolymer composition (or A-side) may contain one or more blocked isocyanate prepolymers, one or more thermally conductive fillers, and other optional additives. The blocked isocyanate prepolymer composition may comprise, in weight percent (wt%), 1% to 40%, 1% to 20%, or 1% to 15% blocked isocyanate prepolymer. The blocked isocyanate prepolymer composition may comprise, in weight percent (wt%), 40% to 99%, 50% to 98%, 60% to 97%, 75% to 95%, or 80% to 94% thermally conductive filler.

[0028] Blocked Isocyanate Prepolymer The blocked isocyanate prepolymer composition may include a blocked isocyanate prepolymer product produced by reacting an isocyanate-terminated prepolymer (including any residual monomeric diisocyanates) with one or more blocking agents. In some cases, reacting the isocyanate groups with a blocking agent reduces the free isocyanate content in the prepolymer to less than 0.1 weight percent, less than 0.01 weight percent, less than 0.001 weight percent, or 0 weight percent.

[0029] The isocyanate-terminated prepolymer may be any prepolymer prepared by the reaction of one or more polyols with a stoichiometric excess of one or more polyisocyanates. "Polyisocyanate" refers to any compound containing two or more isocyanate groups. Polyisocyanates may include monomeric polyisocyanates, polymeric isocyanates, isocyanate prepolymers, or mixtures thereof. Polyisocyanates may be aromatic, aliphatic, araliphatic, or cycloaliphatic polyisocyanates, or mixtures thereof. Preferred polyisocyanates include aromatic polyisocyanates. Aromatic polyisocyanates refer to compounds having at least two or more isocyanate groups attached to aromatic carbon atoms. Suitable polyisocyanates may have an average isocyanate functionality of 1.9 or more, 2.0 or more, 2.1 or more, 2.2 or more, 2.3 or more, and at the same time 4.0 or less, 3.8 or less, 3.5 or less, 3.2 or less, 3.0 or less, 2.8 or less, or 2.7 or less. Examples of suitable monomeric polyisocyanates include toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), methyl ethyl ketone (MDI), methyl ... diisocyanate (HDI), tetramethylene-1,4-diisocyanate, cyclohexane-1,4-diisocyanate, hexahydrotolylene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, 4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-diphenyl diisocyanate, and 3,3'-dimethyldiphenylpropane-4,4'-diisocyanate, their isomers, or mixtures thereof. The preferred monomeric diisocyanate is TDI.

[0030] The isocyanate-terminated prepolymer may include a polyether backbone and an isocyanate moiety. The isocyanate-terminated prepolymer may have an isocyanate content of 1% or more, 2.7% or more, 5% or more, 6% or more, 8% or more, or 10% or more, and at the same time 30% or less, 25% or less, 20% or less, or 15% or less, based on the weight of the isocyanate-terminated prepolymer. The isocyanate content herein is measured according to ASTM D5155-19. The isocyanate used to prepare the isocyanate-terminated prepolymer may include the monomeric polyisocyanates described above, their isomers, their polymeric derivatives, or mixtures thereof. The preferred isocyanate is toluene diisocyanate (TDI), its polymeric derivatives, or mixtures thereof.

[0031] The TDI used to prepare the isocyanate-terminated prepolymers can be, inter alia, the 2,4- and 2,6-isomers of toluene diisocyanate. Toluene diisocyanate-based prepolymers are generally desirable because they provide lower deblocking temperatures along with ease of deblocking and reaction. Mixtures of two or more organic polyisocyanates can also be used.

[0032] The polyol used to prepare the isocyanate-terminated prepolymer can be any polyol known in the art, including, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butenediol, 1,4-butynediol, 1,5-pentanediol, neopentyl-glycol, bis(hydroxy-methyl)cyclohexane, such as 1,4-bis(hydroxymethyl)cyclohexane, 2-methylpropane-1,3-diol, methylpentanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, dibutylene glycol, polybutylene glycol, polyoxyethylene glycol, polyoxypropylene glycol, polyoxypropylene-polyoxyethylene glycol, or mixtures thereof.

[0033] Suitable polyols may include polyether polyols prepared by adding an alkylene oxide, such as ethylene oxide (EO), propylene oxide (PO), butylene oxide (BO), or a combination thereof, to an initiator having 2 to 8 active hydrogen atoms (e.g., such that the initiator includes hydroxyl groups and excludes amines). For example, polyether polyols for polymer formulations may include those having number average molecular weights (Daltons (Da) or g / mol) of 100 to 10,000 Da (e.g., 1,000 Da to 8,000 Da, 2,000 Da to 6,000 Da, 3,000 Da to 5,000 Da, 3,500 Da to 4,500 Da, etc.). Polyether polyols may have a functionality of 2 to 8, at least 2, at least 3, up to 8, or up to 6 active hydrogen atoms per molecule. The polyether polyols used in the prepolymer formation may have a hydroxyl number of 10 to 200 mg KOH / g (e.g., 30 to 60 mg KOH / g, etc.). The one or more polyether polyols may include polyoxypropylene-containing polyols, such as ethylene oxide-capped polyoxypropylene diols or triols and / or polyoxypropylene diols or triols. Exemplary polyether polyols are available from Dow Chemical Company under the trade name VORANOL™. In some embodiments, the functionality of the polyol is 1.9 to 3.1 and the number average molecular weight is 500 to 10,000 Da.

[0034] The preparation of polyols by alkoxylation of initiators can be carried out by procedures known in the art. For example, polyols can be made by adding alkylene oxides (EO, PO, or BO), or combinations of alkylene oxides, to initiators by anionic or cationic reactions, or by using double metal cyanide (DMC) catalysts. In some applications, only one alkylene oxide monomer may be used, in some other applications, a blend of monomers may be used, and in some cases, sequential addition of monomers (such as PO followed by EO feed, or EO followed by PO) may be used.

[0035] In the case of copolymers, the polyether polyols may be block and / or random copolymers as well as capped copolymers. Other useful polyols include polyester polyols, hydroxyl-terminated poly(butadiene) polyols, polyacrylate polyols, and amine-initiated polyols. Exemplary polyols having amine initiators (and which may optionally be autocatalytically active) are available from Dow Chemical Company under the trade names VORANOL™ and VORACTIVE™ polyols.

[0036] The isocyanate-terminated prepolymer may be prepared by standard procedures known to those skilled in the art, for example, as disclosed in U.S. Pat. Nos. 4,294,951, 4,555,562 and 4,182,825, and WO 2004 / 074343. The reactants may be mixed and heated to promote the reaction of the polyol with the polyisocyanate. The reaction temperature may be in the range of 30° C. to 150° C. (e.g., 60° C. to 100° C.). The reaction may be carried out in a moisture-free atmosphere. An inert gas, such as nitrogen and / or argon, may be used to blanket the reaction mixture. If desired, an inert solvent may be used during the preparation of the isocyanate-terminated prepolymer, although the inert solvent may be omitted. A catalyst may be used to promote the formation of urethane bonds. To produce a blocked isocyanate prepolymer, the blocking agent may be added to the polyisocyanate during the formation of the isocyanate prepolymer, after the formation of the isocyanate prepolymer, or prior to the introduction of the polyisocyanate to the polyol. The catalyst may be used in small amounts, for example, each catalyst is used at 0.0015% to 5% by weight of the total weight of the blocked prepolymer to form the blocked isocyanate prepolymer. This amount depends on the catalyst or catalyst mixture and the reactivity of the polyol with the isocyanate, as well as other factors well known to those skilled in the art.

[0037] The isocyanate prepolymers and / or blocked isocyanate prepolymers may be formed using catalysts, which in some embodiments may include amine-based catalysts and / or tin-based catalysts. Exemplary catalysts include tertiary amine catalysts and organotin catalysts. Commercially available examples include trimethylamine, triethylamine, N-methylmorpholine, N-ethylmorpholine, N,N-dimethylbenzylamine, N,N-dimethylethanolamine, N,N-dimethylaminoethyl, N,N,N',N'-tetramethyl-1,4-butanediamine, N,N-dimethylpiperazine, 1,4-diazobicyclo-2,2,2-octane, bis(dimethylaminoethyl)ether, triethylenediamine, dibutyltin dilaurate, triethylenediamine, and dimethylalkylamines in which the alkyl group contains 4 to 18 carbon atoms. Mixtures of various catalysts may also be used.

[0038] Blocked isocyanate prepolymers may be formed in some embodiments by mixing and reacting one or more of the isocyanate functional groups on the isocyanate prepolymer with one or more blocking agents. Blocking agents for reaction with the isocyanate-terminated prepolymer may include monophenols (e.g., a single hydroxyl group [HO-] attached directly to an aromatic ring or aromatic ring), substituted monophenols having at least one substitution atom or group other than hydrogen or hydroxyl on the aromatic ring, substituted monophenols having at least one hydrocarbyl substitution on the aromatic ring, alkylphenols such as nonylphenol, or alkenylphenols such as cardanol. Blocking agents may include cardanol-based blocking agents such as cashew nutshell liquid (CNSL), a by-product of cashew nut processing (e.g., may be extracted from the layer between the nut and the shell of the cashew nut). In some cases, the CNSL may have a cardanol content of at least 85% by weight based on the total weight of the CNSL, such that the CNSL includes cardanol as a major component and may further include cardol, methyl cardol, and / or anacardic acid as minor components. The CNSL may be subjected to a heating process (e.g., upon extraction from the cashew nuts), a decarboxylation process, and / or a distillation process. The CNSL includes at least 85% by weight (e.g., 85% to 100% by weight, 90% to 99% by weight, 91% to 98% by weight, 92% to 98% by weight, 93% to 98% by weight, etc.) of cardanol in weight percent (wt%) based on the total weight of the CNSL. The CNSL may contain less than 8.5 wt.% (e.g., 0.5 wt.% to 8 wt.%, 0.5 wt.% to 5 wt.%, 0.5 wt.% to 3 wt.%, etc.) cardanol, with the remainder based on a total of 100 wt.% being methyl cardanol and / or anacardic acid. The decarboxylated CNSL may optionally be prepared by at least one distillation process. The blocking agent may be used in an amount such that the equivalent amount of blocking agent groups exceeds the amount of isocyanate groups being blocked.The blocking agent may be used in an amount such that the equivalent weight of the blocking agent group corresponds to the amount of isocyanate groups to be blocked. For example, the blocking agent may be added at least 100 mol%, at least 110 mol%, at least 120 mol%, at least 150 mol%, or at least 200 mol% in terms of the mole percent (mol%) of the isocyanate groups to be blocked. In some cases, application of an excess of blocking agent may obtain essentially complete reaction of all isocyanate groups. In some embodiments, the excess of blocking agent may be added at 20 mol% or less, 15 mol% or less, 10 mol% or less, or 5 mol% or less in terms of the mole percent (mol%) of the isocyanate groups to be blocked. For example, the amount of blocking agent group used for isocyanate blocking may be 100 mol% to 110 mol% based on the amount of isocyanate groups of the blocked prepolymer.

[0039] The blocking agent may be present in at least 1 wt%, 3 wt%, 5 wt%, 7 wt%, 9 wt%, 10 wt%, 12 wt%, and / or 13 wt% of the blocked prepolymer. In some embodiments, the blocking agent may be present in up to 14 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, or 70 wt% of the blocked prepolymer. In some embodiments, the blocking agent may be present in 1 wt%-70 wt%, 5 wt%-60 wt%, 7 wt%-50 wt%, or 10 wt%-50 wt% of the blocked prepolymer.

[0040] In some embodiments, the blocked isocyanate prepolymers are made from TDI using an all PO polyol of 500-2500 Da number average equivalent weight and 1.9-3.1 functionality with 2-15% NCO prior to blocking with a blocking agent such as cardanol. The blocked isocyanate prepolymers disclosed herein may also include commercially available blocked isocyanate prepolymers.

[0041] B.) Amine Composition The amine composition (or B-side) may contain one or more amines, one or more thermally conductive fillers, and other additives. The amine composition may include a combination of monoamines, diamines, and higher order amines (e.g., triamines, tetraamines, etc.). Selection of the type and number of amine functional groups may be used in some embodiments to tailor the cure profile and hardness of the final product. For example, selection of an amine or polyamine containing one or more primary amines with higher reactivity may be used to increase the cure speed and overall hardness of the thermally conductive composition.

[0042] In some embodiments, the amine composition may include at least one amine present in weight percent (wt%) of the amine composition from 0.2 wt% to 40 wt%, 0.5 wt% to 30 wt%, or 1 wt% to 15 wt%. The amine composition may include a thermally conductive filler present in weight percent (wt%) of the amine composition from 40 wt% to 98 wt%, 50 wt% to 98 wt%, 60 wt% to 98 wt%, 75 wt% to 98 wt%, or 80 wt% to 98 wt%.

[0043] The amine composition may include one or more secondary or primary amines, including mixtures thereof. Suitable amines may include dicyclohexylamine (DCHA), cyclohexylamine (CHA), ethylene diamine (EDA), isophorone diamine (IPDA), trisaminopropylamine, LAROMINE™, and JEFFAMINE™ polyetheramines. In one embodiment, the amine is an aliphatic amine. In one embodiment, the amine composition may include a polyamine having at least two amine groups that may be independently primary or secondary amines. In another embodiment, the polyamine may contain at least three amine groups that may be independently primary or secondary amines. In yet another embodiment, the polyamine may contain six or fewer amine groups that may be independently primary or secondary amines. The amines in the amine compositions disclosed herein may have an average primary amine functionality and / or an average secondary amine functionality of at least 1.5, at least 2.0, or at least 3.0. The amine composition may also contain an amine having an average primary amine functionality and / or an average secondary amine functionality of 6.0 or less. The amine composition may, in some embodiments, contain one or more amines that are present as a liquid.

[0044] Other moieties coupled with amine functionality may also be utilized. For example, polyetheramines (amine-terminated polyether polyols) may be utilized, including primary and secondary amine-terminated polyether polyols with number average molecular weights greater than 500 Da, having 2-6 amine functionalities, preferably 2-3 amine functionalities, and amine equivalent weights of 100 Da to 7000 Da, 100 Da to 3000 Da, and 100 Da to 2500 Da. Mixtures may also be used. In some embodiments, the amine composition may include one or more polyetheramines with number average molecular weights of 300 Da to 7000 Da and average functionalities greater than 2 and less than 3.5. These materials may be made by a variety of methods known in the art.

[0045] Polyetheramines useful in the present disclosure include resins made from a suitable initiator to which a lower alkylene oxide, such as ethylene oxide, propylene oxide, butylene oxide, or mixtures thereof, is added, and the resulting hydroxyl-terminated polyol is then aminated. When two or more oxides are used, they may be present as a random mixture or as blocks of one or the other polyether. In the amination step, the terminal hydroxyl groups in the polyol may be essentially all secondary hydroxyl groups to facilitate amination. In some cases, amine-terminated polyether resins useful in the present disclosure may have more than 50 percent of their active hydrogens in the form of amine hydrogens. When ethylene oxide is used, the hydroxyl-terminated polyol may be capped with a small amount of a higher alkylene oxide to increase the number of terminal hydroxyl groups that are secondary hydroxyl groups. The polyol so prepared is then reductively aminated by known techniques, such as those described in U.S. Pat. No. 3,654,370, the disclosure of which is incorporated herein by reference.

[0046] In practice, the amine composition may include one or more high molecular weight polyetheramines, including mixtures of difunctional and trifunctional materials and / or different molecular weight or different chemical composition materials. In some embodiments, the amine composition is a primary amine. The term "high molecular weight" is intended to include polyetheramines having a molecular weight ranging from 300 Da to 7000 Da. The amine composition may include one or more polyetheramines, such as the primary aliphatic JEFFAMINE™ series of polyetheramines available from Huntsman Corporation, including JEFFAMINE™ T-403, JEFFAMINE™ T-3000, and JEFFAMINE™ T-5000, or available from BASF, including BAXXODUR™ EC 3003 and BAXXODUR™ EC 311.

[0047] Thermally conductive filler The thermally conductive composition may also optionally include one or more thermally conductive fillers in the A-side and / or B-side composition. The fillers disclosed herein may have a thermal conductivity of at least 1 W / m·K, at least 5 W / m·K, or at least 20 W / m·K. In some embodiments, the fillers disclosed herein may have a thermal conductivity of less than 1000 W / m·K, or less than 100 W / m·K. The fillers disclosed herein may have a low density to reduce the overall weight of the composition and reduce weight in automotive, EV, and other application areas. In an embodiment, the filler density is <6 gm / cc, <4 gm / cc, or <2.5 gm / cc. The fillers disclosed herein may also have a filler density of >0.5 gm / cc. Filler hardness is also a factor in reducing wear and tear of equipment during processing of the material. In some embodiments, the fillers have a Mohs hardness of <9.5, <5.5, <4, or greater than 1.

[0048] The thermally conductive fillers disclosed herein may include one or more of metal oxides, metal nitrides, metal carbides, metal hydroxides, metal carbonates, metal sulfates, natural and synthetic minerals, primarily silicates, and aluminum silicates. Examples of fillers include quartz, fused silica, natural silica, synthetic silica, natural aluminum oxide, synthetic aluminum oxide, aluminum trihydrate (ATH), hollow fillers, beryllium oxide, magnesium oxide, magnesium hydroxide, aluminum oxide hydroxide, boron nitride, aluminum nitride, silicon nitride, silicon carbide, mica, zinc oxide, aluminum nitride, tungsten carbide, mullite, wollastonite, talc, glimmer, kaolin, bentonite, xolite, andalusite, zeolite, dolomite, glass powder / fiber / fabric, other organic or inorganic particulate fillers. Examples of fillers also include barium titanate, carbon fiber, diamond, graphite, onyx, and combinations thereof. Thermally conductive compositions may include, for example, one or more fillers, and mixtures thereof, either added in their final state in the formulation or formed in situ. In some cases, the filler may be both thermally conductive and electrically insulating, as defined by a dielectric strength of greater than 10 kV / mm. Thermally conductive fillers are known in the art and commercially available, see, for example, U.S. Patent No. 6,169,142.

[0049] The fillers disclosed herein may have morphologies including platelet, fibrous, spherical, granular, acicular, etc. shapes, which may be crystalline, semi-crystalline, or amorphous, or any combination thereof. The particles may be spherical, nearly spherical, hemispherical, or irregularly shaped, as long as the aspect ratio is 3 or less, as determined by electron micrographs.

[0050] The thermally conductive fillers of the present disclosure can be modified with a treating agent prior to incorporation into the A-side and / or B-side of the thermally conductive composition. In some cases, modifying the thermally conductive fillers prior to addition to the A-side or B-side components can reduce the increase in viscosity or squeeze force of the components in addition to improving storage stability and handling. For example, the addition of a treating agent to the B-side can result in an undesirable change in the rheology of the composition, which can result in an undesirable increase in the viscosity / squeezing force of the composition.

[0051] The treating agents disclosed herein may be used to alter the hydrophobicity / hydrophilicity of the surface of the thermally conductive filler, improve the interaction of the filler with the polymer, and modify the viscosity and squeeze force of the resulting thermally conductive composition. For example, the filler may be reacted with a treating agent such as a silane (a process also called silanization), which can increase the compatibility of the filler with blocked isocyanate and / or amine compositions. The treating agent may include a fatty acid, a silanating agent, a titanate, a zirconate, an aluminate, or a silazane compound. In some embodiments, the silanating agent may contain at least one alkoxy group to facilitate surface treatment and / or chemical bonding to the filler. The silanating agent may also contain other groups, including, for example, alkyl, hydroxyl, vinyl, allyl, hydrosilyl (i.e., SiH), or other functional groups that may react with or be compatible or miscible with the formulation. The silanating agent may be a silanating agent such as ... n (R') 4-n where n is an integer from 1 to 3, R is independently a C1 to C3 alkyl group, R' is independently a C1 to C20 alkyl group, and at least one R' is selected from C5 to C20. In some embodiments, the silane treating agent may include a C5 to C20 alkyl silane, such as hexadecyltrimethoxysilane.

[0052] The treating agent may be applied to the filler as a pre-treatment prior to introduction to the A-side and / or B-side, or may be provided to the A-side along with the untreated thermally conductive filler. The concentration may vary depending on the nature of the treating agent and the thermally conductive filler type. The treating agents disclosed herein may be added to the filler at weight percent (wt%) of 0.5 wt% to 10 wt%, 0.5 wt% to 7.5 wt%, or 0.5 wt% to 5 wt%. In some embodiments, the treating agent is added only to the A-side of the composition. In some embodiments, the filler is pre-treated prior to addition to the A-side or B-side.

[0053] Filler loadings useful in the thermally conductive compositions of the present disclosure may vary. The thermally conductive fillers disclosed herein may be present in weight percent (wt%) of the total weight of the thermally conductive composition at 40 wt%-98 wt%, 50 wt%-98 wt%, 60 wt%-98 wt%, 75 wt%-98 wt%, or 80 wt%-98 wt%. The fillers may be loaded in the A-side and / or B-side in equal or different amounts that, when combined, result in a thermally conductive composition having a filler concentration within any of the above ranges. It is noted that different filler sizes / types can be blended to obtain the desired filler loading and formulation viscosity.

[0054] The thermally conductive fillers disclosed herein may have a broad particle size distribution and / or may have a bimodal particle size distribution. The thermally conductive fillers have an average particle size (D) sufficient to promote a balance of acceptable processing viscosity before cure and a balance of acceptable thermo-mechanical properties after cure. 50 ) and range. The average D 50 The particle size may be in the range of 0.05 μm to 500 μm, 0.1 μm to 300 μm, 0.5 μm to 100 μm, or 0.5 μm to 50 μm. 90 The particle size may be in the range of 0.05 μm to 500 μm, 1 μm to 300 μm, 5 μm to 100 μm, or 10 μm to 90 μm. 10The particle size may be in the range of 0.05 μm to 30 μm, 0.1 μm to 10 μm, or 0.1 μm to 10 μm. In some cases, the span may be controlled to reduce the squeezing force of the resulting thermally conductive composition.

[0055] The fillers disclosed herein may have a broad particle size characterized by a span of greater than 2, greater than 3, or greater than 4, or less than 50. In some cases, the thermally conductive fillers may have a D range of 0.1 to 20 μm. 50 and the other filler has a D in the range of 10 to 200 μm. 50 The filler may have a bimodal particle size distribution produced by blending two fillers having the following structure:

[0056] A preferred filler is aluminum trihydrate due to its low density and low hardness. A preferred filler has a span >4. D in the range of 0.1 to 10 microns 10 , D in the range of 5 to 50 microns 50 , and D in the range of 50 to 200 microns 90 In one embodiment, the filler is pretreated with a C5-C20 silane treating agent.

[0057] catalyst The thermally conductive composition may include one or more catalysts mixed into at least one of the blocked isocyanate prepolymer composition or the amine composition to promote the reaction of the blocked isocyanate functional groups with the amine groups. The catalyst may be any one or any combination / mixture of two or more selected from carboxylate salts, tertiary amines, amidines, guanidines, and diazabicyclo compounds. In some embodiments, the carboxylate salt is a metal carboxylate, and in further embodiments, a carboxylate salt with a metal alkanoate, in further embodiments, the carboxylate salt is an alkali metal carboxylate, and in further embodiments, the carboxylate salt is an alkali metal alkanoate. Examples of suitable metal alkanoates include bismuth octoate, bismuth neodecanoate, potassium acetate, potassium 2-ethylhexanoate, or mixtures thereof. In some embodiments, the tertiary amine is a sterically hindered tertiary amine, a long chain tertiary amine (i.e., at least six hydrocarbon amine substituents), or a cyclic tertiary amine. Examples of suitable tertiary amines include dimorpholinodialkyl ethers, di((dialkylmorpholino)alkyl)ethers such as (di-(2-(3,5-dimethyl-morpholino)ethyl)ether), triethylenediamine, N,N-dimethylcyclohexylamine, N,N-dimethylpiperazine, 4-methoxyethylmorpholine, N-methylmorpholine, N-ethylmorpholine, or mixtures thereof. In some embodiments, the amidine or guanidine is an N-hydrocarbyl substituted amidine or guanidine. In further embodiments, the amidine or guanidine is a cyclic amidine or cyclic guanidine. Examples of suitable amidines or guanidines include 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5,7-triazabicyclo[4.4.0]dec-5-ene, diazabicyclo[5.4.0]undec-7-ene, and N-methyl-1,5,7-triazabicyclododecene.The catalyst may be present in an amount of 0.001 wt % to 5.0 wt %, 0.01 wt % to 2.0 wt %, or 0.02 wt % to 0.5 wt %, based on the total weight of the two-component curable composition.

[0058] Additives The thermally conductive composition may include one or more additives which may include moisture scavengers (e.g., zeolites, molecular sieves, p-toluenesulfonyl isocyanate), adhesion promoters, thixotropic agents, colorants such as dyes or pigments, antioxidants, wetting agents such as surfactants, filler dispersants, thickeners, compatibilizers, anti-settling agents, anti-syneresis agents, flame retardants, and / or filler treatment agents. Additional optional additives include, but are not limited to, heat stabilizers, paraffins, fatty alcohols, dimethylpolysiloxanes, chain extenders, rheology modifiers and thickeners, e.g., fumed silica AEROSIL R202 or AEROSIL R805 (EVONIK), stabilizers against aging and weathering, plasticizers, antibacterial agents, fungistatic and bacteriostatic substances. In one example, the additive may include a molecular sieve powder such as a zeolite (e.g., SYLOSIV from W.R. Grace), which may be a crystalline aluminosilicate. The molecular sieve may be added at 0.1 wt% to 2 wt% in weight percent (wt%) of the total composition.

[0059] The thermally conductive composition may include a plasticizer mixed with at least one of the blocked isocyanate prepolymer composition or the amine composition in an amount ranging from 1% to 20%, 2% to 16%, or 4% to 15% by weight of the respective compositions. The plasticizer may be a common plasticizer useful in polyurethanes and known to those skilled in the art. The plasticizer may be present in an amount sufficient to disperse or reduce the viscosity of at least one of the blocked isocyanate prepolymer composition or the amine composition. Suitable plasticizers may include soybean oil, phthalates, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB), terephthalates, and the like. Other plasticizers may include alkyl phthalates such as diisononyl phthalate, dioctyl phthalate, and dibutyl phthalate, partially hydrogenated terpenes such as those commercially available as "HB-40", epoxy plasticizers, chloroparaffins, and alkyl naphthalenes.

[0060] The thermally conductive composition may include a dispersing additive in the B-side that stabilizes the filler and other ingredients. The dispersing additive functions to stabilize the particles either through steric, electrosteric, or electrostatic means and may be nonionic, anionic, cationic, or zwitterionic. The structures may be linear polymers and copolymers, head-to-tail modified polymers and copolymers, AB-block copolymers, ABA block copolymers, branched block copolymers, gradient copolymers, branched gradient copolymers, hyperbranched polymers and copolymers including hyperbranched polyesters and copolymers, star polymers and copolymers. BASF, Lubrizol, RT Vanderbilt, and BYK are all common manufacturers of dispersing agents. Trade names include Lubrizol Solsperse series, Vanderbilt Darvan series, BASF Dispex series, BYK DisperByk series, BYK LP-C 2XXXX series. Grades can include BYK DisperByk 162, 181, 182, 190, 193, 2200, and 2152; LP-C 22091, 22092, 22116, 22118, 22120, 22121, 22124, 22125, 22126, 22131, 22134, 22136, 22141, 22146, 22147, 22435; LP-N 22269; Solsperse 3000, and Darvan CN.

[0061] In some embodiments, the dispersion additive is a hyperbranched polyester containing amine groups sterically protected by polyester side chains. The dispersion additives disclosed herein may be present in the B side of the composition in an amount of 0.01% to 2%, 0.1% to 1%, or 0.1% to 0.5% by weight.

[0062] C. Preparation method Prior to combining to form the thermally conductive composition, the blocked isocyanate prepolymer composition and / or the amine composition may have a squeeze force of 250 N or less, 150 N or less, or 85 N or less. The blocked isocyanate prepolymer composition and / or the amine composition may have a squeeze force in the range of 35 N to 250 N, 35 N to 150 N, or 35 N to 85 N. In some embodiments, the blocked isocyanate prepolymer composition and the amine composition may exhibit a viscosity change of <50% over 3 days, or a viscosity change of <20% after heating at 60° C. for 7 days.

[0063] The preparation of the thermally conductive composition of the present disclosure may be accomplished by mixing the respective components of the blocked isocyanate prepolymer composition and the amine composition and combining the components to prepare the final mixture. Suitable mixing techniques include the use of a Ross PD mixer (Charles Ross), a Myers mixer, a FlackTek Speedmixer, or other mixers known in the art that distribute the different components uniformly. The respective formulation components and compositions may generally be added in any order, in various combinations, and at various times of addition, as convenient and desired. Any of the optional additives listed above may be added during or prior to mixing (e.g., added to the blocked isocyanate and / or amine composition) to form the thermally conductive composition. One or more of the formulation components may also be premixed.

[0064] The various components of the composition can also be mixed using a continuous process such as twin screw extrusion. The various streams can be fed separately to the extruder or premixed in various combinations to form the blocked isocyanate and amine compositions. Such a process can be suitable for large scale production.

[0065] The present disclosure also provides a process for preparing a thermally conductive composition, which includes mixing an amine composition with a blocked isocyanate prepolymer composition and the above-mentioned optional components. The amine composition and the blocked isocyanate prepolymer composition can be combined such that the molar ratio of blocked isocyanate groups to amine reactive groups is in the range of 0.90:1.1 to 1.1:0.9, for example, 0.90:1.1, 0.95:1.05, 0.97:1.03, or 1:1. At the same time, the volume ratio of the amine composition to the blocked isocyanate prepolymer composition in the curable composition may be controlled in the range of 0.90:1.1 to 0.95:1.05, 0.97:1.03, or at a ratio of 1:1. Such a volume ratio (i.e., a consistent mixing ratio) indicates that the two-component curable composition can be prepared using existing processing equipment for conventional two-component polyurethane-based compositions.

[0066] The two main components of the thermally conductive composition (i.e., the amine composition and the blocked isocyanate prepolymer composition) are reactive with each other and when contacted or mixed during application undergo a curing reaction, and the reaction product of the two components is a cured thermally conductive composition capable of providing a thermally conductive interface between two surfaces. The mixture of the blocked isocyanate prepolymer composition and the amine composition may be cured at temperatures of 0°C to 60°C, 10°C to 50°C, 15°C to 45°C, or 18°C ​​to 35°C (e.g., RT). Curing may be indicated by an increase in viscosity after mixing of the A-side and the B-side with the eventual formation of a cured thermally conductive solid having a measurable hardness. The cured thermally conductive composition may have a range of hardness as determined by ASTM D-2240-15 ranging from 40 to 95 Shore OO, 50 to 90 Shore OO, or 60 to 85 Shore OO.

[0067] The thermally conductive compositions disclosed herein may cure in less than 14 days, less than 10 days, or less than 7 days, typically on a time scale of more than 30 minutes. The cured thermally conductive compositions may have a thermal conductivity of >0.5 W / m·K, or >1 W / m·K, or most preferably >1.5 W / m·K, or <50 W / m·K. In some embodiments, the cured thermally conductive compositions may have a density of 1 gm / cc to 4 gm / cc, 1.5 to 3.5 gm / cc, or 1.8 to 3.1 gm / cc. Additionally, the viscosity of the A-side and B-side allows for easy processing of the material.

[0068] The thermally conductive compositions disclosed herein can be useful as gap fillers or adhesives for energy storage devices and in electronic vehicle battery thermal management. In some cases, the compositions can be applied between a heat sink, such as a cold plate, and a heat source, such as a battery module, to provide a thermally conductive interface.

[0069] Manual or semi-automated dispensing tools can be used to apply the composition directly to the target surface to minimize waste. In one embodiment, the thermally conductive composition can be prepared by combining the blocked isocyanate prepolymer composition with the amine composition and applying an automated mix dispensing system to a cooling plate or heat sink, followed by installation of a battery cell, module or pack, or other heat source.

[0070] Additionally, the thermally conductive composition may be used to form pre-cured articles such as thermal interface gap pads. In one example, the pre-cured article may be formed by curing the thermally conductive composition to a desired thickness, cutting the article to a desired shape, and then compressing and fixing it in place as needed. The gap pads prepared with the compositions disclosed herein provide and / or improve the thermal interface between the heat sink and the electronic device and may accommodate uneven surfaces, voids, and rough surface textures. In some cases, the cured article may also help reduce vibration stresses for shock damping. EXAMPLES

[0071] In order to test the compositions and methods of the present disclosure, various examples were prepared and tested according to the formulations and test methods listed below. The examples herein are intended to illustrate the present disclosure, but not to limit its scope.

[0072] The chemicals used to prepare the comparative and sample formulations for the examples are shown in Table 1.

[0073] [Table 1]

[0074] preparation The formulations were prepared by combining the individual components and mixing using a high speed mixer. Sides A and B of the formulations were prepared separately. For curing, the two-part compositions (sides A and B) were mixed in a 1:1 weight ratio (unless otherwise specified) using a high speed mixer and allowed to cure at room temperature.

[0075] Test Method Hardness was measured using a Shore OO durometer. Squeeze force was measured using a TA.XTplus texture analyzer equipped with a 50 kg load cell. After each sample was dispensed onto a flat aluminum substrate, an acrylic probe with a 40 mm diameter was lowered to pinch the test material against the flat substrate to achieve a standard gap thickness of 5.0 mm. Any excess overflow material was cut off with a flat edge spatula. After cutting, the test was started and the probe was moved at a rate of 1.0 mm / sec to a final thickness of 0.3 mm while the force was recorded. The specific force value recorded at a gap of 0.5 mm is reported as the "squeeze force". Squeeze force values ​​were measured within 7 days of sample preparation.

[0076] The thermal conductivity of the samples was measured according to ISO 22007-2 using a Hot Disk Thermal Constants Analyzer (TPS 2500S, Thermtest Instruments, Canada). All measurements were performed with a Kapton-encased thermal probe using double-sided measurements with a 2–6 mm cup, with a heating power of 150 mW and a measurement time of 5 s.

[0077] Example 1: Room temperature curable thermally conductive composition Thermally conductive compositions and comparative formulations were prepared and analyzed for cure characteristics and resulting hardness. Table 2 lists the compositions of the tested samples and their respective properties, with E samples representing compositions prepared according to the present disclosure and CE samples representing comparative formulations. Values ​​reported for sample components are provided in grams unless otherwise indicated.

[0078] [Table 2]

[0079] Samples E1 and E2 exhibited high thermal conductivity (>1.5 W / m K), a squeeze force of <150 N, and a Shore OO hardness in the range of 60-90. Samples E1 and E2 also utilize a low density ATH filler, giving a low density end product estimated at approximately 2.0 gm / cc. In contrast, CE1 contains an unblocked isocyanate prepolymer, and when compounded with the filler, the A-side rapidly thickened to a solid within a day, highlighting the incompatibility of the unblocked prepolymer with the reactive groups on the filler and making it unusable as an acceptable gap filler.

[0080] Example 2: Effect of Catalyst on Cure Time Several catalysts were evaluated to determine their effect on the curing properties of the thermally conductive compositions. The A-side compositions shown in Table 3 were cured along with the B-side compositions for E3-E6. Catalyst-1, Catalyst-2, and Catalyst-3 were found to significantly accelerate the curing reaction, with Catalyst-3 being able to induce complete cure in one day at low catalyst loading. CE2 using Catalyst-4 had a much lower cure hardness in one day, demonstrating the benefits of the specific catalysts disclosed herein.

[0081] [Table 3] * E5 hardened immediately after mixing.

[0082] Example 3: Use of plasticizers to control squeeze force The following examples show that very low squeeze forces (<60 N) are achievable with the described compositions. Furthermore, heat aging of the formulations at 60° C. for 2 weeks results in less than a 25% increase in squeeze force, indicating that the compositions are stable.

[0083] [Table 4]

[0084] Example 4: Effect of Dispersion Additives In this example, samples containing a dispersing additive to reduce the squeeze force of the B-side composition were analyzed along with a comparative sample in which the dispersing additive was omitted. Samples were prepared in a Ross double planetary mixer. The results show that CE3 exhibited high squeeze forces (>200N), while the B-side composition was also a poorly workable dry solid. In contrast, the B-side of E8 remained a workable paste at lower squeeze forces (<150N).

[0085] [Table 5]

[0086] Example 5: Filler surface modification In this example, thermally conductive compositions were prepared to investigate the effect of filler surface modification on the resulting viscosity and squeeze force of the A-side and B-side components and their respective storage stability. For the evaluation of storage stability, samples were filled into glass vials, backfilled with nitrogen, taped, and kept in an oven at 60° C. After aging at 60° C. for one week, the samples were cooled to room temperature and then the squeeze force was measured.

[0087] CE4 and CE5 have broad particle size fillers with silanizing agents added without surface treatment. The squeeze force of the B-side for both samples increased significantly after aging at 60° C. for one week. The B-side for samples CE4 and CE5 also had a hard appearance after 7 days of storage at room temperature and required heating to 60° C. to make it a paste.

[0088] E9 and E10 have a wide particle size and pretreated fillers with hydrophobic surface treatment. After aging at 60°C for one week, there was no significant increase in the squeeze force of the B-side. The B-side also remained a paste without the need for any heating. As demonstrated, E9 and E10 produced cured thermally conductive compositions with hardnesses of 73 and 71 Shore OO, respectively.

[0089] [Table 6]

[0090] [Table 7]

[0091] While the forgoing is directed to exemplary embodiments, other and further embodiments may be devised without departing from the basic scope thereof, which is determined by the claims that follow.

Claims

1. A thermally conductive composition comprising: a blocked isocyanate prepolymer composition comprising an isocyanate prepolymer blocked with one or more of an alkylphenol or an alkenylphenol; 1. An amine composition comprising: One or more polyetheramines and an amine composition comprising one or more catalysts selected from the group consisting of carboxylate salts, tertiary amines, amidines, guanidines, and diazabicyclo compounds; a thermally conductive filler present in a weight percent (wt%) range of 60 wt% to 98 wt% of the thermally conductive composition; A thermally conductive composition, wherein the thermally conductive composition cures at a temperature in the range of 18° C. to 35° C. when the blocked isocyanate prepolymer composition and the amine composition are mixed.

2. 2. The composition of claim 1, wherein the amine composition comprises one or more polyetheramines having a molecular weight of 300 to 7000 Da and an average amine functionality of greater than 2.

3. 3. The composition of claim 1 or 2, wherein the thermally conductive filler is modified with a treating agent prior to combining with the thermally conductive composition, the treating agent comprising one or more selected from the group consisting of fatty acids, silane treating agents, titanates, zirconates, aluminates, and silazane compounds.

4. The composition of claim 1 or 2, wherein the thermally conductive filler is pretreated with a C5 to C20 alkyl silane.

5. The composition of claim 1 or 2, wherein the blocked isocyanate prepolymer is present in a weight percent (wt%) range of 1 wt% to 15 wt% of the thermally conductive composition.

6. 3. The composition of claim 1 or 2, further comprising a hyperbranched polyester dispersant additive in the amine composition.

7. The thermally conductive filler has a D in the range of 0.1 to 20 μm. ５０ and one filler having a D in the range of 10 to 200 μm. ５０ 3. The composition of claim 1 or 2, comprising a mixture of aluminum trihydrate (ATH) fillers having a bimodal particle size distribution produced by blending with a second filler having a bimodal particle size distribution.

8. 3. The composition of claim 1 or 2, wherein the blocked isocyanate prepolymer composition and the amine composition each have a squeeze force of 250 N or less as determined by compressing using a probe having a diameter of 40 mm lowered to a gap of 0.5 mm at a rate of 1.0 mm / sec.

9. 3. A thermally conductive gap filler prepared by combining the blocked isocyanate prepolymer composition with the amine composition and curing the resulting thermally conductive composition of claim 1 or 2.

10. 3. A method of using the thermally conductive composition of claim 1 or 2, comprising combining the blocked isocyanate prepolymer composition with the amine composition and installing the thermally conductive composition between a heat source and a heat sink in an EV battery.