Rubber-compatible 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, one or more plasticizers selected from esters of glycol ethers, and an amine composition containing a thermally conductive filler present in a weight percent (wt%) of the thermally conductive composition in a range of 60 wt% to 98 wt%, wherein the thermally conductive composition cures at a temperature in a range of 18°C ​​to 35°C when the blocked isocyanate prepolymer composition and the amine composition are mixed.

Description

[Technical Field]

[0001] This disclosure relates to thermally conductive compositions formulated with plasticizers and other additives having high compatibility with nonpolar materials, and to their use in thermal management methods.

[0002] Introduction Thermal interface materials such as gap fillers, adhesives, and gels are widely used for thermal management in electronic and automotive applications. For example, electric vehicle (EV) batteries are cooled by a cooling plate with a circulating fluid beneath the battery module. Good thermal contact between the battery module and the cooling plate is required for efficient cooling. Gap fillers fill this gap and provide thermal contact between the battery module and the cooling plate. Thermal gap pads and distributable gap fillers are two of the main gap filler technologies. Of the two, distributable gap fillers have the advantage of providing more efficient heat transfer and less material waste 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 portion without the addition of heat, low density, and is easily processable.

[0003] However, there are several significant problems with currently available thermal interface materials. For example, in applications such as EV battery thermal management, silicone is typically used, but it is preferable that the thermal interface material does not contain volatile silicone contamination. This is because silicone contaminants are thought to adversely affect the surface and interface performance of coatings and adhesives in the manufacturing environment.

[0004] Polyurethane (PU) thermal interface formulations based on isocyanate monomers, or isocyanate prepolymers having residual isocyanate monomers, and / or polymer isocyanates having residual isocyanate monomers, present concerns regarding the handling of isocyanate-containing materials. Some material users even impose requirements for less than 0.1% by weight of free isocyanate monomers (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) European Union regulations. Other issues concerning thermally controlled products include the use of additives such as plasticizers to improve processability and reduce compressibility and viscosity. However, plasticizers can leach and penetrate into surrounding materials in contact with the thermal interface material, which can lead to physical changes and degradation. [Overview of the project]

[0005] In one embodiment, the thermally conductive composition comprises 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, one or more plasticizers selected from glycol ether esters, and a thermally conductive filler present in the range of 60% to 98% by weight (weight%) of the 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. [Modes for carrying out the invention]

[0006] Embodiments disclosed herein relate to thermally conductive compositions formulated with plasticizers and other additives having high compatibility with nonpolar materials, and their use in methods of thermal management, including improving heat transfer in batteries, electronic devices, and automotive applications. The thermally conductive compositions are formulated as a two-component mixture, which 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 until combined for use and exhibit a minimal increase in viscosity or squeeze force.

[0007] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this disclosure pertains. Furthermore, all publications, patent applications, patents, and other references referenced herein are incorporated by reference.

[0008] Numerical ranges disclosed herein include all values ​​from the lower limit to the upper limit, including the lower and upper limits. Ranges containing explicit values ​​(e.g., 1 or 2, or 3 to 5, or 6 or 7) include any sub-range between any two explicit values ​​(e.g., 1 to 2, 2 to 6, 5 to 7, 3 to 7, 5 to 6, etc.). Unless otherwise stated, implied in the context, or customary in the art, all parts and percentages are based on weight, and all test methods are current as of the filing date of this disclosure.

[0009] Where disclosed herein, the terms “composition,” “formulation,” or “mixture” refer to a physical blend of different components obtained by mixing components by parts by weight using physical means. The sum of the weight percentages of each component in a composition is 100% by weight based on the total weight of the composition.

[0010] As used herein, the term “average particle size” refers to the median particle size or diameter of the particle distribution, determined, for example, by a Multisizer 3 Coulter Counter (Beckman Coulter, Inc., Fullerton, CA) according to the manufacturer’s recommended procedure. This is the volume-average particle size. Median particle size D 50 This is defined as a size where 50% of the particles in the distribution are smaller than the median particle size, and 50% of the particles in the distribution are larger than the median particle size. 90 This is defined as the size of 90% of the particles in the distribution being smaller than a specified value. 10 The average particle size is defined as the size of 10% of the particles in the distribution being smaller than a specified value. The average particle size can be estimated based on measuring the surface area according to 8-11 ASTM D4315, or by calculating the average from the cumulative weight of each particle group using sieves of various mesh sizes. These alternative methods give estimates of the average particle size similar to those determined by laser diffraction. The span of the filler particle size distribution is (D 90 -D 10 ) / D 50 It is defined as an indicator of the width of the particle size distribution.

[0011] In this specification, “and / or” means “and, or alternatively.” All scopes include the endpoint unless otherwise indicated.

[0012] As disclosed herein, “non-polar materials” include natural and synthetic rubbers used in sealing applications, such as butyl rubber, EPDM-type rubber, halogenated butyl rubber, and copolymers of isobutylene and alkylstyrene.

[0013] Where disclosed herein, “room temperature” means a temperature range of 18°C ​​to 35°C.

[0014] Where disclosed herein, “curing” and “cured” mean an increase in viscosity or compressibility after mixing, accompanied by the final curing of the material and the formation of solid portions resulting from crosslinking of polymer chains.

[0015] Where disclosed herein, "molecular weight" means number-average molecular weight.

[0016] Where disclosed herein, “thermally conductive filler” means a thermal conductivity value greater than 1 W / m·K as measured by ISO 22007-2 using a hot disk.

[0017] Where disclosed herein, “thermally conductive composition” (including both cured and uncured compositions) means a composition having a thermal conductivity value greater than 0.5 W / m·K as measured by ISO 22007-2 using a hot disk, for example.

[0018] Where disclosed herein, “compression force” refers to the resistance of a thermally conductive composition or component to compression measured in Newtons. Compression force is measured using a TA.XTplus texture analyzer equipped with a 50 kg load cell. After distributing each sample onto a flat aluminum substrate, an acrylic probe with a diameter of 40 mm is lowered to sandwich the test material against the flat substrate, achieving a standard gap thickness of 5.0 mm. Any excess overflow material is trimmed off with a flat-edge spatula. After trimming, the test is initiated, and the probe is moved at a speed of 1.0 mm / second to a final thickness of 0.3 mm while recording the force. The specific force value recorded at a 0.5 mm gap is reported as “compression force”.

[0019] Viscosity can be measured using a TA instruments ARES-G2, AR2000 rheometer, or Anton Paar MCR rheometer, with a parallel plate fixture, using methods commonly known in the art.

[0020] The thermally conductive composition disclosed in the present specification may be used for heat management applications including improvement of heat transfer in electronic devices, batteries, automotive applications and the like. For example, the described composition can be used as a thermally conductive gap filler for applications requiring heat management such as electric vehicle batteries. After being applied to an EV battery assembly, the gap filler contacts other parts of the battery assembly, including sealant materials that prevent moisture and dust from entering the battery. Among many sealant materials used, butyl rubber is one of the commonly used sealant materials. Over time, with prolonged contact with the thermal interface material, non-polar plasticizers added to reduce squeezing force during battery pack assembly can migrate to the surrounding sealing material. Plasticizer penetration can reduce the integrity and flexibility of the sealant material, which can lead to loss of seal and exposure of components.

[0021] The thermally conductive composition disclosed in the present specification may be formulated with a plasticizer that increases processability while also being compatible with non-polar materials such as butyl rubber. For example, plasticizers may be selected that have properties such as polarity, water solubility, and viscosity, which, along with low squeezing force during installation, minimize leaching of the plasticizer into the surrounding non-polar materials used in combination with the gap filler.

[0022] The thermally conductive composition disclosed in the present specification generally comprises a product obtained from combining a blocked isocyanate prepolymer composition ("Side A"), which is a two-component curable composition, and an amine composition ("Side B"). During application, Side A and Side B are mixed to initiate a curing reaction between the blocked isocyanate and amine functional groups at room temperature, forming the thermally conductive composition. The thermally conductive composition may also contain one or more thermally conductive fillers on Side A and Side B to improve heat transport properties.

[0023] The blocked isocyanate prepolymer composition comprises an isocyanate prepolymer that reacts with a blocking agent to limit the presence of free isocyanates (e.g., to a concentration of less than about 0.1% by weight), and minimize premature gelation and crosslinking of the prepolymer. Reducing the free isocyanate concentration also improves storage, safety, and handling properties. In addition to safety benefits, blocking the isocyanate functional groups 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 to the A-side and / or B-side of the thermally conductive composition in a weight percentage (wt%) of up to 60 wt% or more. The thermally conductive compositions disclosed herein are also compatible with low-density, low-cost fillers such as aluminum trihydrate.

[0024] The thermally conductive composition can be prepared by mixing the blocked isocyanate prepolymer composition and an 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 at room temperature increases the applicability of the material to heat-sensitive applications such as electric vehicle batteries, and brings the additional benefit of reduced energy consumption during manufacturing.

[0025] This disclosure also relates to methods for preparing and using thermally conductive compositions. A thermally conductive composition can be prepared by combining a blocked isocyanate prepolymer composition with an amine composition, wherein at least one of the blocked isocyanate prepolymer composition or the amine composition comprises a thermally conductive filler. The filler and thermally conductive filler may also be treated to increase surface hydrophobicity and storage stability, while also reducing premature viscosity increases. The thermally conductive composition may also contain one or more additives, such as dispersants or plasticizers, that reduce the viscosity or compressive force of the thermally conductive composition. Reducing the viscosity and compressive 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 the heat source and the heat sink. Reducing the force in the system reduces the likelihood of damaging battery module components and increases reproducibility and safety. In particular, the use of blocked isocyanate prepolymer compositions reduces concerns about free isocyanate monomers or volatile silicones 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, thixotropes, catalysts, colorants, antioxidants, wetting agents, filler treatment agents, surface treatment additives, or combinations thereof. A catalyst may be mixed into the B side of the two-component curable composition. In some embodiments, the two-component curable compositions disclosed herein can be cured to form thermally conductive gap fillers or gap pads.

[0027] A.) Blocked isocyanate prepolymer composition The blocked isocyanate prepolymer composition (or side A) may contain one or more blocked isocyanate prepolymers, one or more thermally conductive fillers, and other optional additives. The blocked isocyanate prepolymer composition may contain 1% to 40% by weight, 1% to 20% by weight, or 1% to 15% by weight of blocked isocyanate prepolymers. The blocked isocyanate prepolymer composition may also contain thermally conductive fillers present in 40% to 99% by weight, 50% to 98% by weight, 60% to 97% by weight, 75% to 95% by weight, or 80% to 94% by weight.

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

[0029] An isocyanate-terminated prepolymer can be any prepolymer prepared by the reaction of one or more polyols with one or more polyisocyanates in stoichiometric excess. “Polyisocyanate” refers to any compound containing two or more isocyanate groups. Polyisocyanates may include monomeric polyisocyanates, polymeric isocyanates, isocyanate prepolymers, or mixtures thereof. Polyisocyanates can be aromatic, aliphatic, araliphatic, or alicyclic polyisocyanates, or mixtures thereof. Preferred polyisocyanates include aromatic polyisocyanates. An aromatic polyisocyanate refers to a compound having at least two isocyanate groups bonded to an aromatic carbon atom. Suitable polyisocyanates may have an average isocyanate functional value of 1.9 or higher, 2.0 or higher, 2.1 or higher, 2.2 or higher, 2.3 or higher, and simultaneously, 4.0 or lower, 3.8 or lower, 3.5 or lower, 3.2 or lower, 3.0 or lower, 2.8 or lower, or 2.7 or lower. Examples of suitable monomer polyisocyanates include toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), and hexamethylene diisocyanate (hexamethylene diisocyanate). Examples include diisocyanates (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 contain a polyether backbone and an isocyanate moiety. Based on the weight of the isocyanate-terminated prepolymer, the isocyanate-terminated prepolymer may have an isocyanate content of 1% or more by weight, 2.7% or more by weight, 5% or more by weight, 6% or more by weight, 8% or more by weight, or 10% or more by weight, and simultaneously, 30% or less by weight, 25% or less by weight, 20% or less by weight, or 15% or less by weight. The isocyanate content as used herein is measured according to ASTM D5155-19. Examples of isocyanates used to prepare the isocyanate-terminated prepolymer include the monomeric polyisocyanates described above, their isomers, their polymer derivatives, or mixtures thereof. Preferred isocyanates are toluene diisocyanate (TDI), its polymer derivatives, or mixtures thereof.

[0031] The TDIs used to prepare isocyanate-terminated prepolymers may, among other things, be 2,4-isomers and 2,6-isomers of toluene diisocyanate. Toluene diisocyanate-based prepolymers are generally preferred because they result in lower deblocking temperatures, along with ease of deblocking and reaction. Mixtures of two or more organic polyisocyanates may also be used.

[0032] The polyols used to prepare isocyanate-terminated prepolymers may 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(hydroxymethyl)cyclohexane, for example, 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 include polyether polyols prepared by adding alkylene oxides such as ethylene oxide (EO), propylene oxide (PO), butylene oxide (BO), or combinations thereof, to an initiator having 2 to 8 active hydrogen atoms (e.g., the initiator contains a hydroxyl group and excludes amines). For example, polyether polyols for polymer formulations may have a number average molecular weight (Dalton (Da) or g / mol) of 100 to 10000 Da (e.g., 1000 Da to 8000 Da, 2000 Da to 6000 Da, 3000 Da to 5000 Da, 3500 Da to 4500 Da, etc.). Polyether polyols may have a functional value 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 for prepolymer formation may have a hydroxyl value of 10 to 200 mg KOH / g (e.g., 30 to 60 mg KOH / g). One or more polyether polyols may include polyoxypropylene-containing polyols such as ethylene oxide-capped polyoxypropylene-diol or triol and / or polyoxypropylene-diol or triol. Exemplary polyether polyols are available from Dow Chemical Company under the trade name VORANOL®. In some embodiments, the functional value of the polyol is 1.9 to 3.1, and the number-average molecular weight is 500 to 10000 Da.

[0034] The production of polyols by alkoxylation of initiators can be carried out by procedures known in the art. For example, polyols can be produced by adding alkylene oxides (EO, PO, or BO), or combinations of alkylene oxides, to an initiator by anionic or cationic reaction, or by the use of a double metal cyanide (DMC) catalyst. 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, or EO followed by PO) may be used.

[0035] In the case of copolymers, polyether polyols may be block and / or random copolymers and 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 optionally being autocatalytically active) are available from Dow Chemical Company under the trade names VORANOL® and VORACTIVE® polyols.

[0036] Isocyanate-terminated prepolymers can be prepared by standard procedures known to those skilled in the art, as disclosed, for example, in U.S. Patents 4,294,951, 4,555,562, and 4,182,825, and International Publication No. 2004 / 074343. The reactants may be mixed and heated to promote the reaction between the polyol and the polyisocyanate. The reaction temperature will 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. The reaction mixture may be covered with an inert gas such as nitrogen and / or argon. If desired, an inert solvent may be used during the preparation of the isocyanate-terminated prepolymer, but the inert solvent may be omitted. A catalyst that promotes the formation of urethane bonds may be used. To produce blocked isocyanate prepolymers, blocking agents may be added to the polyisocyanate during the formation of the isocyanate prepolymer, after the formation of the isocyanate prepolymer, or before the introduction of the polyisocyanate into the polyol. Catalysts may be used in small amounts; for example, each catalyst is used in an amount of 0.0015% to 5% by weight of the total weight of the blocked prepolymer for forming the blocked isocyanate prepolymer. This amount depends on the catalyst or catalyst mixture, the reactivity of the polyol and isocyanate, and other factors well known to those skilled in the art.

[0037] Isocyanate prepolymers and / or blocked isocyanate prepolymers may, in some embodiments, be formed using catalysts that may include amine-based catalysts and / or tin-based catalysts. Exemplary catalysts include tertiary amine catalysts and organotin catalysts. Examples of commercially available catalysts 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 containing alkyl groups with 4 to 18 carbon atoms. Mixtures of various catalysts may also be used.

[0038] Blocked isocyanate prepolymers can be formed in some embodiments by mixing and reacting one or more isocyanate functional groups on an isocyanate prepolymer with one or more blocking agents. Blocking agents for reaction with isocyanate-terminated prepolymers may include monophenols (e.g., aromatic rings or single hydroxyl groups [HO-] directly bonded to aromatic rings), substituted monophenols having at least one substituted atom or group other than hydrogen or hydroxyl on the aromatic ring, substituted monophenols having at least one hydrocarbyl substituent on the aromatic ring, alkylphenols such as nonylphenol, or alkenylphenols such as cardanol. Blocking agents may also include cardanol-based blocking agents such as cashew nutshell liquid (CNSL), a byproduct of cashew nut processing (e.g., extracted from the layer between the nut and shell of a cashew nut). In some cases, CNSL may have a cardanol content of at least 85% by weight based on the total weight of CNSL, and as a result, CNSL may contain cardanol as the main component and further contain cardol, methylcardol, and / or anacardic acid as minor components. CNSL can be subjected to heating processes (e.g., when extracted from cashew nuts), decarboxylation processes, and / or distillation processes. CNSL contains 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 CNSL. CNSL may contain less than 8.5% by weight of cardanol (e.g., 0.5% to 8% by weight, 0.5% to 5% by weight, 0.5% to 3% by weight, etc.), with the remainder based on a total of 100% by weight being methylcardanol and / or anacardic acid. Decarboxylated CNSL may, in some cases, be prepared by at least one distillation process. Blocking agents may be used in amounts such that the equivalent amount of the blocking agent group exceeds the amount of isocyanate group being blocked.The blocking agent may be used in an amount such that the equivalent amount of the blocking agent group corresponds to the amount of isocyanate groups to be blocked. For example, the blocking agent may be added in a molar percentage (mol%) of at least 100 mol%, at least 110 mol%, at least 120 mol%, at least 150 mol%, or at least 200 mol% of the isocyanate groups to be blocked. In some cases, the application of an excess of the blocking agent may result in an essentially complete reaction of all isocyanate groups. In some embodiments, the excess blocking agent may be added in a molar percentage (mol%) of at least 20 mol%, at least 15 mol%, at least 10 mol%, or at least 5 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 in the prepolymer to be blocked.

[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 weight percentage (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 weight percentage (wt%) of the blocked prepolymer. In some embodiments, the blocking agent may be present in 1 wt% to 70 wt%, 5 wt% to 60 wt%, 7 wt% to 50 wt%, or 10 wt% to 50 wt% of the weight percentage (wt%) of the blocked prepolymer.

[0040] In some embodiments, blocked isocyanate prepolymers are prepared from TDI using all PO polyols having a number average equivalent of 500-2500 Da and a functional value of 1.9-3.1, with 2-20% NCO, before being blocked with a blocking agent such as cardanol. The blocked isocyanate prepolymers disclosed herein may also include commercially available blocked isocyanate prepolymers.

[0041] B.) Amine compositions The amine composition (or side B) may contain one or more amines, one or more thermally conductive fillers, and other additives. The amine composition may also contain combinations of monoamines, diamines, and higher-order amines (e.g., triamines, tetraamines, etc.). The selection of the type and number of amine functional groups may be used in some embodiments to adjust the curing profile and hardness of the final product. For example, the selection of amines or polyamines containing one or more primary amines with higher reactivity may be used to increase the curing rate and overall hardness of the thermally conductive composition.

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

[0043] The amine composition may contain one or more secondary or primary amines (including mixtures thereof). Suitable amines 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 contain a polyamine having at least two amine groups that can independently be primary or secondary amines. In another embodiment, the polyamine may contain at least three amine groups that can independently be primary or secondary amines. In yet another embodiment, the polyamine may contain six or fewer amine groups that can independently be primary or secondary amines. The amines in the amine compositions disclosed herein may have an average primary and / or secondary amine functional value of at least 1.5, at least 2.0, at least 2.5, at least 3.0, or at least 3.5. The amine compositions may also contain amines having an average primary and / or secondary amine functional value of 6.0 or less. In some embodiments, the amine compositions may contain one or more amines present as liquids.

[0044] Other parts bonded to amine functional groups may also be utilized. For example, polyetheramines (amine-terminated polyether polyols) may be utilized that contain primary and secondary amine-terminated polyether polyols with a number average molecular weight greater than 500 Da, with 2 to 6 amine functional groups, preferably 2 to 3 amine functional groups, and amine equivalents 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 contain one or more polyetheramines having a number average molecular weight of 300 Da to 7000 Da and an average functional value greater than 2. These materials may be prepared by various methods known in the art.

[0045] Examples of polyetheramines useful in this disclosure include resins prepared from suitable initiators to which lower alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, or mixtures thereof are added, and the resulting hydroxyl-terminated polyols are then aminated. When two or more oxides are used, they may exist 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 this disclosure may have more than 50 percent of their active hydrogen in the form of amine hydrogens. When ethylene oxide is used, the hydroxyl-terminated polyol may be capped with a small amount of higher alkylene oxide to increase the number of terminal hydroxyl groups that are secondary hydroxyl groups. The polyols thus prepared are then reductively aminated by known techniques, such as those described in U.S. Patent No. 3,654,370, which is incorporated herein by reference.

[0046] In practice, the amine composition may include one or more high molecular weight polyetheramines, including difunctional and trifunctional materials and / or mixtures of materials with different molecular weights or different chemical compositions. In some embodiments, the amine composition is a primary amine. The term “high molecular weight” is intended to include polyetheramines having molecular weights in the range of 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 include BAXXODUR® EC 3003 and BAXXODUR® EC 311 available from BASF.

[0047] Thermally conductive filler The thermally conductive composition may also optionally contain 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 to reduce weight in automotive, EV, and other application areas. In one 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 that reduces 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 1 or higher.

[0048] The thermally conductive fillers disclosed herein may comprise one or more of the following: metal oxides, metal nitrides, metal carbides, metal hydroxides, metal carbonates, metal sulfates, natural and synthetic minerals, mainly silicates, and aluminum silicate. 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 hydroxide oxide, 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 / cloth, and other organic or inorganic particulate fillers. Other examples of fillers include barium titanate, carbon fiber, diamond, graphite, onyx, and combinations thereof. The thermally conductive composition may include, for example, one or more fillers, and mixtures thereof, which are either added to the formulation in their final state or formed in situ. In some cases, the fillers may be both thermally conductive and electrically insulating, as defined by a dielectric strength greater than 10 kV / mm. Thermally conductive fillers are known and commercially available in the art; see, for example, U.S. Patent No. 6,169,142.

[0049] The fillers disclosed herein may have forms including plate-like, fibrous, spherical, granular, and needle-like shapes, and these may be crystalline, semi-crystalline, amorphous, or any combination thereof. The particles may be spherical, nearly spherical, hemispherical, or irregular in shape, as determined by electron micrographs, provided that their aspect ratio is 3 or less.

[0050] The thermally conductive fillers of this disclosure can be modified with a treatment agent before being incorporated into the A and / or B side of a thermally conductive composition. In some cases, modifying the thermally conductive filler before adding it to the A or B side component can improve storage stability and handling, as well as reduce increases in viscosity or compressibility of the composition. For example, adding a treatment agent to the B side can result in undesirable changes in the rheology of the composition, which in turn can lead to an undesirable increase in viscosity / compressibility of the composition.

[0051] The treatment agents disclosed herein may be used to alter the hydrophobicity / hydrophilicity of the surface of a thermally conductive filler, improve the interaction between the filler and the polymer, and modify the viscosity and compressibility of the resulting thermally conductive composition. For example, the filler may be reacted with a treatment agent such as a silane (a process also known as silanization), thereby increasing the compatibility of the filler with blocked isocyanate and / or amine compositions. Examples of treatment agents include fatty acids, silane treatment agents, titanates, zirconates, aluminates, or silazane compounds. In some embodiments, the silane treatment agent may contain at least one alkoxy group to facilitate surface treatment and / or chemical bonding to the filler. The silane treatment agent may also contain another group, for example, alkyl, hydroxyl, vinyl, allyl, hydrosilyl (i.e., SiH), or other functional groups that can react with or be compatible or miscible with the formulation. The silane treatment agent may contain Si(OR) n (R') 4-n The chemical structure may be as follows, 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.

[0052] The treating agent may be applied to the filler as a pretreatment before introduction into the A side and / or B side, or may be provided on the A side together with an untreated thermally conductive filler. The concentration may vary depending on the nature of the treating agent and the type of thermally conductive filler. The treating agent disclosed herein may be added to the filler in an amount of 0.5 wt% to 10 wt%, 0.5 wt% to 7.5 wt%, or 0.5 wt% to 5 wt% by weight percent (wt%). In some embodiments, the treating agent is added only to the A side of the composition. In some embodiments, the filler is pretreated before being added to the A side or B side.

[0053] The addition amount of the filler useful in the thermally conductive composition of the present disclosure may vary. The thermally conductive filler disclosed herein may be present in an amount of 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% based on the total weight percent (wt%) of the thermally conductive composition. The filler may be filled into the A side and / or B side in equal amounts or different amounts that, when combined, result in a thermally conductive composition having any filler concentration within the above ranges. It should be noted that different filler sizes / types can be blended to obtain the desired filler loading and formulation viscosity.

[0054] The thermally conductive filler disclosed herein may have a broad particle size distribution and / or may have a bimodal particle size distribution. The thermally conductive filler has a sufficient average particle diameter (D 50 ) and width to promote an acceptable balance of processing viscosity before curing and an acceptable balance of thermomechanical properties after curing. The average D of the filler disclosed herein 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. The average D of the filler disclosed herein 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. The average D of the filler disclosed herein 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 compressive force of the resulting thermally conductive composition.

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

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

[0057] catalyst The thermally conductive composition may contain one or more catalysts mixed with at least one of a blocked isocyanate prepolymer composition or an amine composition to facilitate the reaction between the blocked isocyanate functional group and the amine group. The catalyst may be any combination / mixture of one 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 octanoate, bismuth neodecanoate, potassium acetate, potassium 2-ethylhexanoate, or mixtures thereof. In some embodiments, the tertiary amine is a sterically hindered tertiary amine, in further embodiments, the tertiary amine is a long-chain tertiary amine (i.e., at least six hydrocarbon amine substituents), and in further embodiments, the tertiary amine is 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. Suitable examples of 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 amounts of 0.001% to 5.0% by weight, 0.01% to 2.0% by weight, or 0.02% to 0.5% by weight, based on the total weight of the two-component curable composition.

[0058] plasticizer The thermally conductive composition may contain a plasticizer mixed with at least one of a blocked isocyanate prepolymer composition or an amine composition in an amount of about 1% to about 20% by weight, about 2% to about 15% by weight, or about 5% to about 15% by weight, in each composition.

[0059] Plasticizers disclosed herein include various types of glycol ether esters, including mixtures of one or more types. Preferred glycol ether esters include formula (I) [ka] In the formula, R1 is a saturated, unsaturated, and / or substituted carbon chain containing 2 to 12 carbon atoms, R2 is either hydrogen or methyl, R3 is a C2 to C12 carbon chain, and n is an integer in the range of 1 to 4. Examples include monoesters as described by [source].

[0060] The glycol ether esters disclosed herein are also of formula (II) [ka] In the formula, R1 and R4 are independently saturated, unsaturated, and / or substituted carbon chains containing 2 to 12 carbon atoms, R2 is either hydrogen or methyl, R3 is a saturated, unsaturated, and / or substituted carbon chain containing 2 to 12 carbon atoms, and n is an integer in the range of 1 to 4. It may also contain diesters such as those described by [the relevant authority].

[0061] The glycol ether esters disclosed herein are also of formula (III) [ka] In the formula, R1 and R3 are independently saturated, unsaturated, and / or substituted carbon chains containing 2 to 12 carbon atoms, R2 is either hydrogen or methyl, and n is an integer from 1 to 4. It may also contain diesters such as those described by [the relevant authority].

[0062] Suitable plasticizers include glycol ether esters prepared by esterifying a glycol ether with one or more equivalents of a carboxylic acid. The glycol ether may contain one to four repeating glycol units, including ethylene glycol and propylene glycol. Examples of carboxylic acids include C2-C12 carboxylic acids such as acetic acid, propanoic acid, isobutanoic acid, adipic acid, 2-ethylhexanoic acid, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, and maleic acid. The carboxylic acid may also include monocarboxylic acids and dicarboxylic acids.

[0063] Examples of suitable plasticizers include ethylene glycol monoethyl ether acetate, ethylene glycol monomethyl ether acetate, bis-dipropylene glycol n-butyl ether adipate, bis-dipropylene glycol n-butyl ether maleate, triethylene glycol di-2-ethylhexanoate, bis(2-(2-butoxyethoxy)ethyl) adipate, bis-diethylene glycol n-butyl ether malonate, bis-diethylene glycol n-butyl ether glutarate, bis-dipropylene glycol methyl ether maleate, tetraethylene glycol di-2-ethylhexanoate, and propylene glycol methyl ether acetate.

[0064] In some embodiments, the plasticizer may include bis-dipropylene glycol n-butyl ether adipate, triethylene glycol-di-2-ethylhexanoate, bis(2-(2-butoxyethoxy)ethyl) adipate, tetraethylene glycol di-2-ethylhexanoate, or a combination thereof.

[0065] While not limited by theory, the polarity of the plasticizer may be selected to control the compressive force of the formulation under application (higher polarity results in increased thickness and compressive force), as well as the penetration rate into surrounding non-polar materials such as sealants. For example, the polarity of the plasticizer may be controlled to be unfavorable to penetration and softening into non-polar materials (e.g., butyl rubber), minimizing the increase in compressive force of components A and B. Other relevant factors that affect the penetration rate may include water solubility, viscosity, and boiling point. In some embodiments, the thermally conductive compositions disclosed herein may be compatible with butyl rubber, as indicated by the butyl rubber Shore 00 hardness, which does not change by more than 10%, more than 20%, or more than 30% after contact with the thermally conductive composition at 60°C for 28 days.

[0066] The plasticizers disclosed herein may have water solubility in the ranges of 5 mg / L to 10,000 mg / L, 10 mg / L to 5,000 mg / L, or 20 mg / L to 3,000 mg / L, and may be relatively polar. The water solubility of the plasticizer can be measured by methods commonly known in the art, such as ASTM E1148-02. 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 amine composition. In some embodiments, the plasticizer may have a viscosity of less than 25 cps, less than 30 cps, or less than 35 cps. The plasticizer may have a viscosity in the range of 1 cps to 35 cps, 1 cps to 30 cps, or 5 cps to 30 cps. The plasticizer may also have a boiling point greater than 300°C at 1 atm (760 mmHg) to minimize or eliminate plasticizer loss due to evaporation during testing and use. The plasticizer may have a boiling point at 1 atmosphere (760 mmHg) in the range of 300°C to 1000°C, 290°C to 1000°C, or 290°C to 950°C. The listed ranges may be combined in any order to define a class of plasticizer. For example, the plasticizers disclosed herein may have a water solubility in the range of 5 mg / L to 10,000 mg / L, a viscosity in the range of 1 cps to 30 cps, and a boiling point at 1 atmosphere (760 mmHg) in the range of 290°C to 1000°C. Mixtures of different plasticizers can be used. The plasticizers can be prepared by methods commonly known in the art. The plasticizers are commercially available.

[0067] additives The thermally conductive composition may contain one or more additives, including moisture scavengers (e.g., zeolites, molecular sieves, p-toluenesulfonyl isocyanates), adhesion promoters, thixotropes, colorants such as dyes or pigments, antioxidants, wetting agents such as surfactants, filler dispersants, thickeners, compatibilizers, 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, such as fumed silica AEROSIL R202 or AEROSIL R805 (EVONIK), stabilizers against aging and weathering, plasticizers, antimicrobial agents, fungistatic and bacteriostatic substances. For example, the additive may include molecular sieve powder such as zeolite (e.g., SYLOSIV from WRGrace), which may be a crystalline aluminosilicate. The molecular sieve may be added in an amount of about 0.1% to about 2% by weight of the total composition.

[0068] The thermally conductive composition may include a dispersion additive that stabilizes the filler and other components in at least one of the blocked isocyanate prepolymer composition or amine composition. The dispersant functions to stabilize the particles by any means of steric, electrosteric, or electrostatic means and can be nonionic, anionic, cationic, or zwitterionic. The structures may be linear polymers and copolymers, head-tail modified polymers and copolymers, AB-block copolymers, ABA block copolymers, branched block copolymers, gradient copolymers, branched gradient copolymers, superbranched polymers and copolymers including superbranched polyesters and copolymers, star polymers and copolymers. BASF, Lubrizol, RT Vanderbilt, and BYK are all common manufacturers of dispersants. Trade names include the Lubrizol Solsperse series, Vanderbilt Darvan series, BASF Dispex series, BYK DisperByk series, and BYK LP-C 2XXXX series. The grades may 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.

[0069] C. Preparation method Before being combined to form a thermally conductive composition, the blocked isocyanate prepolymer composition and / or amine composition may have a compressive force of 150 N or less, 100 N or less, or 85 N or less. The blocked isocyanate prepolymer composition and / or amine composition may have a compressive 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 amine composition may exhibit a viscosity change of <50% over 3 days, or a viscosity change of <20% after heating at 60°C over 7 days.

[0070] The preparation of the thermally conductive compositions of this disclosure can be achieved by mixing the respective components of the blocked isocyanate prepolymer composition and the amine composition, and then combining the components to prepare a final mixture. Preferred 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 uniformly distribute different components. Each formulation component and composition can generally be added conveniently and as desired, in any order, in various combinations, and in various numbers of additions. Any of the above-mentioned optional classified additives may be added during or before mixing to form the thermally conductive composition (e.g., added to the blocked isocyanate and / or amine composition). One or more of the formulation components may also be pre-mixed.

[0071] The various components of the composition can also be mixed using a continuous process such as twin-screw extrusion. Different flows can be fed separately to the extruder, or pre-mixed in various combinations to form blocked isocyanate and amine compositions. Such a process may be suitable for mass production.

[0072] This disclosure also provides a process for preparing a thermally conductive composition, the process comprising 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 adjusted so 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 within the range of 0.90:1.1 to 0.95:1.05, 0.97:1.03, or 1:1. Such volume ratios (i.e., consistent mixing ratios) indicate that two-component curable compositions can be prepared using existing processing equipment for conventional two-component polyurethane compositions.

[0073] 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, upon contact or mixing during application, undergo a curing reaction, with the reaction product of the two components being a cured thermally conductive composition that can provide a thermally conductive interface between the 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., room temperature). Curing may be indicated by an increase in viscosity after mixing of side A and side B, resulting in the final formation of a cured thermally conductive solid with measurable hardness. The cured thermally conductive composition may have a hardness range determined by ASTM D-2240-15, ranging from 40 to 95 Shore OO, 40 to 90 Shore OO, 50 to 90 Shore OO, or 60 to 85 Shore OO. In some embodiments, the thermally conductive composition has a hardening hardness of ≥40 Shore 00 as determined by ASTM D-2240-15.

[0074] The thermally conductive compositions disclosed herein can be cured in less than 14 days, less than 10 days, or less than 7 days, generally on a timescale of more than 30 minutes. The cured thermally conductive compositions may have a thermal conductivity of >0.5 W / m·K, >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. Furthermore, the viscosities of sides A and B allow for easy processing of the material.

[0075] The thermally conductive compositions disclosed herein may be useful as gap fillers for energy storage devices and in the thermal management of electronic vehicle batteries. In some cases, the compositions may be applied between a heat sink, such as a cooling plate, and a heat source, such as a battery module, to provide a thermally conductive interface.

[0076] Manual or semi-automatic dispensing tools can be used to apply the composition directly to the target surface and minimize waste. In one embodiment, a thermally conductive composition may be prepared by combining a blocked isocyanate prepolymer composition with an amine composition, applying an automated mixing, metering, and dispensing system to a cooling plate or heat sink, and subsequently installing a battery cell, module, or pack, or other heat source.

[0077] Furthermore, thermally conductive compositions may be used to form pre-cured articles such as thermal interface gap pads. In one example, a pre-cured article may be formed by curing a thermally conductive composition to a desired thickness, cutting the article into a desired shape, and then compressing it as necessary to fix it in place. Gap pads prepared with the compositions disclosed herein may provide and / or improve the thermal interface between a heat sink and an electronic device and may adapt to uneven surfaces, voids, and rough surface textures. In some cases, the cured article may also help reduce vibration stress for shock damping. [Examples]

[0078] To test the compositions and methods of this disclosure, various examples were prepared and tested according to the formulations and test methods listed below. The examples herein are intended to illustrate the disclosure and are not intended to limit its scope.

[0079] Table 1 shows the chemical substances used to prepare the comparative and sample formulations for the examples. [Table 1]

[0080] preparation The formulations were prepared by combining the individual components and mixing them using a high-speed mixer. The A and B parts of the formulation were prepared separately. For curing, the two-part compositions (A and B) were mixed in a 1:1 weight ratio (unless otherwise specified) using a high-speed mixer and cured at room temperature.

[0081] Test method Hardness was measured using a Shore 00 durometer. Compression force was measured using a TA.XTplus texture analyzer equipped with a 50 kg load cell. After distributing each sample onto a flat aluminum substrate, a 40 mm diameter acrylic probe was lowered to clamp the test material against the flat substrate, achieving a standard gap thickness of 5.0 mm. Any excess overflow material was trimmed off with a flat-edge spatula. After trimming, the test was started, and the probe was moved at a speed of 1.0 mm / second to a final thickness of 0.3 mm while recording the force. The specific force value recorded at a 0.5 mm gap was reported as the "compression force".

[0082] The thermal conductivity of the sample was measured according to ISO 22007-2 using a Hot Disk Thermal Constants Analyzer (TPS 2500S, Thermtest Instruments, Canada). All measurements were performed using a Kapton case-enclosed thermal probe with double-sided measurement using two 6 mm cups, with a heating output of 150 mW and a measurement time of 5 seconds. Three measurements were performed with a 5-minute rest period between readings.

[0083] Example: Room temperature curable composition having rubber compatibility Thermally conductive compositions and comparative formulations were prepared, and their curing properties and resulting hardness were analyzed. Tables 2A-B and 23 list the compositions of the tested samples and their respective properties, where sample E represents the composition prepared according to this disclosure, and samples CE represent the comparative formulation. Reported values ​​for sample components are given in grams unless otherwise indicated. All samples were cured and monitored at room temperature for 7 days.

[0084] To test compatibility with butyl rubber, 175g each of side A and side B of each composition were mixed and spread onto a 6-inch x 12-inch aluminum plate using a spatula. 6mm aluminum shims were placed on both sides of the aluminum plate to control the sample thickness. A polytetrafluoroethylene (PTFE) sheet was placed on top of the gap filler, the 6-inch x 12-inch top aluminum plate was applied, and the assembly was compressed by applying paper clips to the four corners of the aluminum plate. The sample was cured at room temperature for 3-4 days, after which the top plate and PTFE were removed, and excess sample was removed from the sides. Butyl rubber beads (4mm square) approximately 4-6 inches long were applied to the center of the test specimen and lightly tapped to provide good contact. The sample was then placed in a 60°C oven. To monitor the degradation of the butyl rubber, the sample was periodically removed, cooled, and the hardness of the butyl rubber was measured using a Shore 00 durometer. The hardness of the butyl rubber was qualitatively analyzed by using a wooden tongue depressor to touch and pull the sample, determining whether the rubber softened or lost its integrity due to plasticizer migration. The initial hardness of the butyl rubber was approximately 55 Shore 00. [Table 2] [Table 3] [Table 4]

[0085] Comparative example CE1 shows that when the non-polar plasticizer soy methyl ester was used, the butyl rubber lost its integrity and hardness. Comparative example CE2 shows that curling of the test specimen was observed, indicating evaporation loss of the low-boiling-point plasticizer (the boiling point of TXIB is 280°C). CE3 shows that the compressive force was very high when a high-viscosity (>25 cps) plasticizer was used. CE4 showed high compressive force with the use of a high-polarity (water solubility >10,000 mg / L) plasticizer. CE5 incorporated a low-polarity (water solubility <3.2 mg / L) plasticizer, and the hardness of the butyl rubber was lost after 28 days of exposure.

[0086] For samples E1 to E4, butyl rubber showed minimal changes in integrity and measurable hardness. All E1 to E4 samples had low compressive forces of approximately 100 N or less, hardness of approximately 60 to 90 Shore 00, and relatively high thermal conductivity (>1.9 W / mK).

[0087] The above describes exemplary embodiments, but other further embodiments may be devised without departing from their basic scope, the scope of which is determined by the following claims. The present specification includes the following embodiments. Section 1. A thermally conductive composition, A blocked isocyanate prepolymer composition comprising an isocyanate prepolymer blocked with one or more alkylphenols or alkenylphenols, An amine composition containing one or more polyetheramines, One or more plasticizers selected from glycol ether esters, The thermal conductive composition comprises a thermal conductive filler present in a weight percentage (weight%) range of 60% to 98% by weight, The thermally conductive composition is a thermally conductive composition that 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. Section 2. The composition according to claim 1, wherein the one or more plasticizers are selected from the group consisting of bis-dipropylene glycol n-butyl ether adipate, triethylene glycol-di-2-ethylhexanoate, bis(2-(2-butoxyethoxy)ethyl) adipate, and tetraethylene glycol di-2-ethylhexanoate. Section 3. The composition according to claim 1 or 2, wherein the thermally conductive composition is compatible with butyl rubber, as indicated by the butyl rubber hardness not changing by more than 20% after contact with the thermally conductive composition at 60°C for 28 days. Section 4. The composition according to any one of claims 1 to 3, wherein the amine composition comprises one or more catalysts selected from the group consisting of carboxylate salts, tertiary amines, amidines, guanidines, and diazabicyclo compounds. Section 5. The composition according to any one of claims 1 to 4, wherein the one or more plasticizers have a water solubility in the range of 5 mg / L to 10,000 mg / L, a viscosity of 1 to 30 cps, and a boiling point in the range of 290°C to 1000°C at 1 atm (760 mmHg). Section 6. The composition according to any one of claims 1 to 5, wherein the thermally conductive composition has a hardened hardness of 40 to 90 Shore 00 as determined by ASTM D-2240-15. Section 7. The thermally conductive filler is a D in the range of 0.1 to 20 μm. 50 A filler having and D in the range of 10-200 μm 50 The composition according to any one of claims 1 to 6, comprising a mixture of aluminum trihydrate (ATH) fillers having a bimodal particle size distribution, prepared by blending with a second filler having the same properties. Section 8. The composition according to any one of claims 1 to 7, wherein the blocked isocyanate prepolymer composition and the amine composition each have a compressive force of 150 N or less, determined by compression using a probe having a diameter of 40 mm lowered to a gap of 0.5 mm at a speed of 1.0 mm / second. Section 9. A thermally conductive gap filler prepared by combining the blocked isocyanate prepolymer composition with the amine composition, and curing the resulting thermally conductive composition according to any one of items 1 to 8. Section 10. A method for using a thermally conductive composition as described in any one of paragraphs 1 to 8, 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.

Claims

1. A thermally conductive composition, A blocked isocyanate prepolymer composition comprising an isocyanate prepolymer blocked with one or more alkylphenols or alkenylphenols, An amine composition containing one or more polyetheramines, One or more plasticizers selected from glycol ether esters, The thermal conductive composition comprises a thermal conductive filler present in a weight percentage (weight%) range of 60% to 98% by weight, 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. A thermally conductive composition in which one or more plasticizers are selected from the group consisting of bis-dipropylene glycol n-butyl ether adipate, triethylene glycol-di-2-ethylhexanoate, bis(2-(2-butoxyethoxy)ethyl) adipate, and tetraethylene glycol di-2-ethylhexanoate.

2. The composition according to claim 1, wherein, after contacting butyl rubber at 60°C for 28 days, the hardness of the butyl rubber does not change by more than 20%.

3. The composition according to claim 1, wherein the amine composition comprises one or more catalysts selected from the group consisting of carboxylates, tertiary amines, amidines, guanidines, and diazabicyclo compounds.

4. The composition according to claim 1, wherein one or more plasticizers have a water solubility in the range of 5 mg / L to 10,000 mg / L, a viscosity of 1 to 30 cps, and a boiling point in the range of 290°C to 1000°C at 1 atm (760 mmHg).

5. The composition according to claim 1, wherein the thermally conductive composition has a hardened hardness of 40 to 90 Shore OO as determined by ASTM D-2240-15.

6. The thermally conductive filler is a D in the range of 0.1 to 20 μm. ５０ A filler having and D in the range of 10 to 200 μm ５０ The composition according to claim 1, comprising a mixture of aluminum trihydrate (ATH) fillers having a bimodal particle size distribution, produced by blending with a second filler having the same properties.

7. The composition according to claim 1, wherein when the blocked isocyanate prepolymer composition and the amine composition are each sandwiched between flat substrates and compressed from a gap thickness of 5.0 mm to a gap thickness of 0.5 mm at a speed of 1.0 mm / second, they have a compressive force of 150 N or less (the composition's resistance to compression).

8. A thermally conductive gap filler prepared by combining the blocked isocyanate prepolymer composition with the amine composition, and curing the resulting thermally conductive composition according to any one of claims 1 to 7.

9. A method for using the thermally conductive composition according to any one of claims 1 to 7, 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.

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