Blocked isocyanate prepolymer for thermally conductive composition

Abstract

Thermally conductive compositions may include an isocyanate component, an isocyanate-reactive component and one or more thermally conductive fillers present in one or more of the isocyanate component and the isocyanate-reactive component. The isocyanate component includes a blocked isocyanate prepolymer formed from a reaction of a first prepolymer, prepared from the reaction of one or more polyols comprising an amine-initiated polyol and a polyisocyanate, and an alkyl phenol. The isocyanate-reactive component includes one or more polyetheramine.

Description

[0001] BLOCKED ISOCYANATE PREPOLYMER FOR THERMALLY CONDUCTIVE COMPOSITION Technical Field The present disclosure relates generally to thermally conductive compositions and more particularly to blocked isocyanate prepolymers for use in thermally conductive compositions. Background Thermal management of battery modules in an electric vehicle (EV) is important to the range, reliability and safety of the EV. Battery modules in an EV are typically cooled by using cooling plates with active cooling, where thermal contact between the modules and the cooling plate contributes to the efficiency of heat transfer. For efficient cooling of EV battery modules or cells, good thermal contact between the battery cells / modules and the cooling plate is needed. A thermal interface material (TIM) provides a thermally conductive pathway between the battery cell / module and the cooling plate for an efficient thermal contact. Thermally conductive gap fillers and adhesives are commonly used in TIMs. High thermal conductivity in the range of 0.5-3 W / m.K is typically needed for TIMs. Most TIM compositions typically have high loading (>80 wt. %) of thermally conductive fillers to be able to achieve such high thermal conductivity. Developing TIM compositions having fast curing times with sufficient hardness in reasonable amounts of time is a continuing challenge. In an effort to meet this challenge, TIM compositions have used catalysts to improve cure times. Amine catalysts or organometallic catalysts are commonly used to accelerate the curing kinetics of TIM compositions. However, the use of catalysts is not preferred due to a variety of reasons, including health and safety considerations. Therefore, there is a need in the art for a catalyst free route in TIM formulations. Summary The aforementioned needs are met by various aspects of the present disclosure. Embodiments of the present disclosure provide for thermally conductive compositions that provide for fast curing times with sufficient hardness in reasonable amounts of time to address the above discussed need in the art. In addition, the thermally conductive composition of the present disclosure may minimize or eliminate the requirements for catalysts during the cure of the thermally conductive composition. The present disclosure provides for a thermally conductive composition that includes an isocyanate component, an isocyanate-reactive component and one or more thermally conductive fillers present in one or more of the isocyanate component and the isocyanate- reactive component. The isocyanate component includes a blocked isocyanate prepolymer formed from a reaction of (a) a first prepolymer prepared from the reaction of one or more polyols comprising an amine-initiated polyol and a polyisocyanate, where the amine-initiated polyol has a hydroxyl number of 20 to 1,000 and (b) an alkyl phenol, where the first prepolymer and the alkyl phenol are reacted to form the blocked isocyanate prepolymer. For the various embodiments, the blocked isocyanate prepolymer can be formed from the reaction of (b) the alkyl phenol and the first prepolymer at an equivalent ratio of 1:0.9 to 1:1.1 (first prepolymer:alkyl phenol) to form the blocked isocyanate prepolymer. The isocyanate-reactive component includes one or more polyetheramine. For the various embodiments, the reaction of (a) the amine-initiated polyol and the polyisocyanate can further include a polypropylene oxide containing polyol, where the polypropylene oxide containing polyol and the amine-initiated polyol are present in the reaction mixture at a weight ratio in the range of 0.98:0.2 to 0.2:0.98 (polypropylene oxide containing polyol:amine-initiated polyol). For the various embodiments, the amine-initiated polyol is formed using a tri-amine initiator. For the various embodiments, the amine-initiated polyol is formed using a bis-3-aminopropylmethylamine initiator. For the various embodiments, the polyisocyanate is a toluene diisocyanate. For the various embodiments, the alkyl phenol is cardanol. For the various embodiments, the blocked isocyanate prepolymer has a % NCO of at least 2 % before blocking. In more specific embodiments, the blocked isocyanate prepolymer has a % NCO of 2 to 25 % before blocking. For the various embodiments, the blocked isocyanate prepolymer has a % NCO of less than 0.5. For the various embodiments, the thermally conductive composition can further include an alkylalkoxysilane comprising an alkyl chain of C12 or more present at a percent by weight (wt.%) of 1.5 wt.% or more based on the weight of the isocyanate component. For the various embodiments, the thermally conductive composition can further include one or more glycol ether ester plasticizers at a percent by weight (wt.%) of the isocyanate component and / or the isocyanate-reactive component ranging from 1 wt.% to 20 wt.%. For the various embodiments, the one or more polyetheramines can include at least one high molecular weight polyether amine having a functionality of 2.5 to 3.5 and a number average molecular weight of 3000 Da or more, and at least one low molecular weight polyether amine having a functionality of 2.5 to 3.5 and a number average molecular weight of 3000 Da or less. For the various embodiments, the thermally conductive filler is aluminum trihydrate (ATH). For the various embodiments, the thermally conductive composition can further include one or more internal mold release agents present in one or more of the isocyanate component and / or the isocyanate-reactive component, the internal mold release agent being prepared from the reaction of one or more equivalents of fatty acid with a branched C3 to C10 polyol. For the various embodiments, the thermally conductive composition can further include a monofunctional polyethylene glycol. For the various embodiments, the thermally conductive composition has a Shore 00 hardness of greater than 60 after 10 days cure at 25 ⁰C. The present disclosure also provides for a thermal interface material prepared by combining the isocyanate component and the isocyanate-reactive component and curing the resulting thermally conductive composition as provided herein. The present disclosure also provides for a method of using the composition as provided herein, where the method includes combining the isocyanate component and the isocyanate-reactive component; and emplacing the thermally conductive composition between a heat source and a heat sink in an EV battery. Detailed Description Embodiments disclosed herein relate to a thermally conductive composition for use in thermal management applications, including enhancing heat transmission in batteries, electronic devices, automotive applications, and the like. Described compositions can be used as a thermally conductive gap filler, thermally conductive adhesive or a pre-cured thermal pad for applications requiring thermal management, such as electric vehicle batteries. Thermally conductive compositions disclosed herein generally include the product obtained from combining a two-component curable composition: an isocyanate component (“A-side”) and an isocyanate-reactive component (“B-side”). During application, the A-side and B-side are mixed, initiating a curing reaction at room temperature, which forms the thermally conductive composition. Thermally conductive compositions also include one or more thermally conductive fillers present in one or more of the isocyanate component and the isocyanate-reactive component to enhance thermal transport properties. Specifically, the thermally conductive composition of the present disclosure includes an isocyanate component and an isocyanate-reactive component that are combined and applied in situ to cure, for example, at room temperature and when cured exhibit a durable Shore OO hardness. For the various embodiments, the isocyanate component includes a blocked isocyanate prepolymer formed from a reaction of (a) a first prepolymer prepared from the reaction of one or more polyols comprising an amine-initiated polyol and a polyisocyanate, where the amine-initiated polyol has a hydroxyl number of 20 to 1,000, and (b) an alkyl phenol, where the first prepolymer and the alkyl phenol are reacted to form the blocked isocyanate prepolymer. For the various embodiments, the blocked isocyanate prepolymer can be formed from the reaction of (b) the alkyl phenol and the first prepolymer at an equivalent ratio of 1:0.9 to 1:1.1 (first prepolymer:alkyl phenol) to form the blocked isocyanate prepolymer. For the various embodiments, the isocyanate-reactive component includes one or more polyetheramine. For the various embodiments, the use of the amine-initiated polyol helps to improve the curing kinetics of the thermally conductive composition. The thermally conductive composition of the present disclosure may further include combinations of one or more alkylalkoxysilanes, glycol ether ester plasticizers and / or internal mold release agents, each as described herein, that help to reduce viscosity and increase the workability of the thermally conductive composition of the present disclosure. For example, the thermally conductive composition of the present disclosure can display reductions in the squeeze force required during preparation and application, while also producing materials that remain stable during curing at, for example, room temperature. Reducing the viscosity and squeeze force of the components of the thermally conductive composition may be beneficial, for example, by reducing the force required to assemble a gap filler between a heat source and a heat sink, such as in an EV battery application. The numerical ranges disclosed herein include all values from, and including, the lower and upper value and all values in between. Unless stated to the contrary, implicit from 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. 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, CA) according to the procedure recommended by the manufacturer. The median particle size, D50 is defined as the size wherein 50 volume % (vol.%) of the particles in the distribution are smaller than the median particle size and 50 vol.% of the particles in the distribution are larger than the median particle size. D90is defined as the size wherein 90 vol.% of the particles in the distribution are smaller than the stated value. D10 is defined as the size wherein 10 vol.% of the particles in the distribution are smaller than the stated 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 and calculating the average from the cumulative weight of each size fractions. These alternative methods give estimations of the average particle sizes similar to those determined by the laser diffraction method. The span of the filler particle size distribution is defined as (D90-D10) / D50 and is an indication of the width of the particle size distribution. As disclosed herein, “room temperature” (“RT”) means a temperature range from 18 °C to 35 °C. As disclosed herein, “molecular weight” means number average molecular weight. As disclosed herein, “thermally conductive filler” means a thermal conductivity value greater than 1 W / m•K as measured by ISO 22007-2 using hot disc or by ASTM D-5470. As disclosed herein, “thermally conductive composition” (which includes 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 hot disc or by ASTM D-5470. As disclosed herein, “squeeze force” refers to resistance of a thermally conductive composition or component to compression, as measured in Newtons. Squeeze force is measured using a TA.XTplus texture analyzer equipped with a 50 kg load cell. After dispensing the respective 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 to achieve a standard 5.0 mm gap thickness. Any excess overflow material was trimmed away with a flat-edge spatula. After trimming, the test started and the probe moved to a final thickness of 0.3 mm, at a rate of 1.0 mm / sec while the force was recorded. The specific force value recorded at the gap of 0.5 mm is reported as the “squeeze force”. Viscosity can be measured using methods commonly known in the art using TA instruments ARES-G2, AR2000 type rheometers or Anton Paar MCR rheometers using parallel plate or cone and plate fixtures. As discussed, the thermally conductive composition of the present disclosure includes an isocyanate component and an isocyanate-reactive component that are combined and applied in situ to cure. For the various embodiments, the isocyanate component includes a blocked isocyanate prepolymer formed from a reaction of (a) a first prepolymer prepared from the reaction of one or more polyols comprising an amine-initiated polyol and a polyisocyanate to form a first prepolymer and (b) an alkyl phenol, where the first prepolymer and the alkyl phenol are reacted to form the blocked isocyanate prepolymer. For the various embodiments, the blocked isocyanate prepolymer can be formed from the reaction of (b) the alkyl phenol and the first prepolymer at an equivalent ratio of 1:0.9 to 1:1.1 (first prepolymer:alkyl phenol) to form the blocked isocyanate prepolymer. For the various embodiments, the isocyanate-reactive component includes one or more polyetheramine. For the various embodiments, the thermally conductive composition further includes one or more thermally conductive fillers present in one or more of the isocyanate component and the isocyanate-reactive component. Each of these components is discussed as follows. For the various embodiments, the isocyanate component (or A-side) contains the blocked isocyanate prepolymer, as provided herein, and may include other additives such as internal mold release (IMR) agents, one or more alkylalkoxysilanes, and other additives such as glycol ether ester plasticizers and thermally conductive fillers. For the isocyanate component, the blocked isocyanate prepolymer is formed from a reaction of (a) one or more polyols comprising an amine-initiated polyol and a polyisocyanate to form a first prepolymer and (b) the first prepolymer and an alkyl phenol to form the blocked isocyanate prepolymer. Reaction with the alkyl phenol may limit the presence of free isocyanate (e.g., below a concentration of 0.5 or even 0.1 wt.%) and minimize premature gelation and crosslinking of the prepolymer. In some cases, reacting the isocyanate groups of the first prepolymer with the alkyl phenol reduces the free isocyanate content in the prepolymer to less than 0.5 wt.%, less than 0.3 wt.%, less than 0.1 wt.%, or zero wt.%. For the various embodiments, the blocked isocyanate prepolymer as provided herein can have a free isocyanate content of less than 0.5 wt.%. The first prepolymer may be prepared by the reaction of one or more polyols comprising an amine-initiated polyol and a polyisocyanate, where there is a stoichiometric excess of the polyisocyanates. For the present disclosure, a polyisocyanate as used herein contains two or more isocyanate groups. The polyisocyanates may be aromatic, aliphatic, araliphatic or cycloaliphatic polyisocyanates, or mixtures thereof. Suitable polyisocyanates include toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tetramethylene-l,4-diisocyanate, cyclohexane-l,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; isomers thereof, or mixtures thereof. Suitable polyisocyanates may have an average isocyanate functionality of 1.9 or more, 2.0 or more, 2.1 or more, or 2.2 or more, and at the same time, 3.5 or less, 3.2 or less, 3.0 or less, or 2.8 or less. The first prepolymer may have an isocyanate (NCO) content by weight (% NCO) according to ASTM D5155-19 of 1% or more, 2.7% or more, or 5% or more, and at the same time, 30% or less, 25% or less, or 20% or less before blocking. So, for the various embodiments, the blocked isocyanate prepolymer has a % NCO of at least 2 % before blocking. In additional embodiments, the blocked isocyanate prepolymer can have a % NCO of 2 to 25 % before blocking. The polyisocyanates used to prepare the first prepolymer can include the above stated monomeric isocyanates, isomers thereof, polymeric derivatives thereof, or mixtures thereof. In some cases, isocyanates may include toluene diisocyanate, polymeric derivatives thereof, or mixtures thereof. For the various embodiments, the polyisocyanate can be toluene diisocyanate (TDI). TDI used to prepare the polyisocyanate may be 2,4-isomer and the 2,6- isomer of toluene diisocyanate among others. Toluene diisocyanate based polyisocyanates may result in lower deblocking temperatures along with high conversion and reaction rates. Mixtures of two or more polyisocyanates may also be used. The one or more polyols used to prepare the first prepolymer include one or more of an amine-initiated polyol, where the amine-initiated polyol can be from 0.5 to 100 wt.% based on the total weight of the one or more polyols used to prepare the first prepolymer. In some embodiments, the one or more polyols used to prepare the first prepolymer can also include another type of polyol, which can be a non-amine-initiated polyol. Each polyol type may include one kind of polyol. Alternatively, each polyol type may include mixtures of different kinds of polyols. In some embodiments, one polyol type may be one kind of polyol whereas the other polyol type may be a mixture of different kinds of polyols. The at least one amine-initiated polyol improves the reactivity of the thermally conductive composition system. As shown in the Examples below, without the amine- initiated polyol of the present disclosure being used (Comparative Examples), the curing kinetics of the Comparative Examples are slow as compared to the Examples that include the amine-initiated polyol of the present disclosure, which demonstrate comparatively rapid curing kinetics. The at least one amine-initiated polyol comprises a functionality of from 2 to 8, or from 2 to 7, or from 2 to 6. As used herein, “functionality” refers to the number of isocyanate reactive sites per molecule. Further, the at least one amine-initiated polyol comprises a hydroxyl number of from 20 to 1,000, or from 20 to 500, or from 20 to 100. As used herein, “hydroxyl number” is a measure of the concentration of reactive hydroxyl groups available for reaction. This number is determined in a wet analytical method and is reported as the number of milligrams of potassium hydroxide equivalent to the hydroxyl groups found in one gram of the sample. The most commonly used methods to determine hydroxyl number are described in ASTM D 4274 D. Still further, the at least one amine-initiated polyol comprises a molecular weight not to exceed 12,000 g / mol, or not to exceed 8,000 g / mol. Amine-initiated polyols suitable for use according to this disclosure are made by alkoxylating one or more amine initiators with one or more alkylene oxides. Suitable amine initiators include, but are not limited to, toluene diamine, methylamine, ethylenediamine, diethylenetriamine, aniline, aminoethylethanolamine, bis-3-aminopropylmethylamine, propylenediamine, tetra- or hexamethyleneamine, triethanolamine, phenylenediamine, and combinations of two or more thereof. Preferably, the amine-initiated polyol of the present disclosure is formed using a tri-amine initiator. Preferably, the amine-initiated polyol is formed using a bis-3-aminopropylmethylamine initiator. The initiator compound is caused to react with at least one alkylene oxide to produce the amine-initiated polyol. The alkylene oxide may be ethylene oxide, 1,2-propylene oxide, 1,2- or 2,3-butylene oxide, tetramethylene oxide or a combination of two or more thereof. If two or more alkylene oxides are used, they may be added to the initiator compound simultaneously (to form a random copolymer) or sequentially (to form a block copolymer). Butylene oxide and tetramethylene oxide are generally less preferred. Ethylene oxide, propylene oxide and mixtures thereof are more preferred. Mixtures of ethylene oxide and propylene oxide may contain the oxides in any proportion. For example, a mixture of ethylene oxide and propylene oxide may contain from 0 to 90 weight percent of ethylene oxide, preferably from 5 to 70 weight percent ethylene oxide or from 10 to 60 weight percent ethylene oxide. In additional embodiments, the reaction of (a) the amine-initiated polyol and the polyisocyanate can further include a polypropylene oxide containing polyol, where the polypropylene oxide containing polyol and the amine-initiated polyol are present in the reaction mixture at a weight ratio in the range of 0.98:0.2 to 0.2:0.98 (polypropylene oxide containing polyol:amine-initiated polyol). The alkoxylation reaction is conveniently performed by forming a mixture of the alkylene oxide(s) and the initiator compound, and subjecting the mixture to conditions of elevated temperature and superatmospheric pressure. Polymerization temperatures may be, for example from 110 to 170 °C, and pressures may be, for example, from 200 to 1000 kPa (2 to 10 bar). A catalyst may be used, particularly if more than one mole of alkylene oxide(s) is to be added per equivalent of amine hydrogen on the initiator compound. Suitable alkoxylation catalysts include strong bases such as alkali metal hydroxides (sodium hydroxide, potassium hydroxide, cesium hydroxide, for example), as well as the so-called double metal cyanide catalysts (of which zinc hexacyanocobaltate complexes are most notable). The reaction can be performed in two or more stages, in which no catalyst is used in the first stage, and from 0.5 to 1.0 mole of alkylene oxide is added to the initiator per equivalent of amine hydrogens, followed by one or more subsequent stages in which additional alkylene oxide is added in the presence of a catalyst as described. After the reaction is completed, the catalyst may be deactivated and / or removed. Alkali metal hydroxide catalysts may be removed, left in the product, or neutralized with an acid and the residues left in the product. Residues of double metal cyanide catalysts may be left in the product, but can be removed instead if desired. The polyols and polyol mixtures used to prepare the blocked isocyanate prepolymer may include ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentylglycol, bis(hydroxy-methyl) cyclohexanes such as 1,4-bis(hydroxymethyl)cyclohexane, 2- methylpropane-1,3-diol, methylpentanediols, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, polyether polyols, and the like. For example, the thermally conductive composition can include a monofunctional polyethylene glycol. The blocked isocyanate prepolymer may be prepared by procedures such as those described in U.S. Patent Nos.4,294,951; 4,555,562; and 4,182,825; and International Publication No. WO 2004 / 074343. Isocyanate prepolymers and / or blocked isocyanate prepolymers may be formed using a catalyst in some embodiments, which may include amine-based catalysts and / or tin-based catalysts. In contrast, the thermally conductive composition of the present disclosure may minimize or eliminate the requirements for catalysts during the cure of the thermally conductive composition. In other words, the catalysts provided herein are used for the synthesis of blocked prepolymer and not the thermally conductive composition of the present disclosure. The blocked isocyanate prepolymer, in some embodiments, may be formed by mixing and reacting one or more of the isocyanate functionalities on an isocyanate prepolymer with one or more blocking agents. Blocking agents for forming the blocked isocyanate prepolymer may include monophenolics; alkyl phenols such as nonylphenol; or alkyl phenols such as cardanol or mixtures, such as cashew nutshell liquid, and the like, and derivatives and mixtures of any thereof. For the various embodiments, the alkyl phenol is cardanol. The blocking agent may be used in an amount such that the equivalents of the functional groups of the blocking agent correspond to the amount of isocyanate groups to be blocked, in molar or excess equivalents. In some embodiments, the blocked isocyanate prepolymer is made from TDI using a combination of polyols with one polyol of equivalent weight of 250 to 2500 Da and functionality 1.9 to 3.1, and another amine initiated polyol with an equivalent weight of 250 to 2500 Da, functionality 1.9 to 4.1 with the wt.% of amine initiated polyol in the total polyol ranging from 0.5 wt. % to 100 wt. %, 2 wt.% to 75 wt.% ; 5 wt.% to 25 wt. %; the prepolymer can have 2% to 25% NCO before blocking with a blocking agent such as cardanol. The isocyanate component may include a blocked isocyanate prepolymer at a percent by weight (wt.%) of 0.5 wt.% to 20 wt.%, 1 wt.% to 15 wt.%, or 1 wt.% to 5 wt.%. Isocyanate components may include a thermally conductive filler present at a percent by weight (wt.%) of 50 wt.% to 95 wt.%, 75 wt.% to 94 wt.%, or 80 wt.% to 92 wt.%. In some cases, the thermally conductive composition can also include an alkylalkoxysilane. For example, the thermally conductive composition can include an alkylalkoxysilane comprising an alkyl chain of C12 or more present at a percent by weight (wt.%) of 1.5 wt.% or more based on the weight of the isocyanate component. Examples of such alkylalkoxysilane compounds include those having a chemical structure of Si(OR)n(R’)4-n, where n is an integer from 1 to 3, R is independently a C1 to C3 alkyl group, and R’ is independently an alkyl chain of C12 or more, such as C12 to C25, or C12 to C20. Suitable alkylalkoxysilanes include dodecyltrimethoxysilane, tridecyltrimethoxysilane, tetradecyltrimethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane, and the like. In one embodiment, alkylalkoxysilane is hexadecyltrimethoxysilane. Alkylalkoxysilanes may have a boiling point greater than 200°C, 250 °C or 300 °C, and less than 1000 °C. Alkylalkoxysilanes disclosed herein may be added at a percent by weight (wt.%) of the isocyanate component ranging from 1.5 wt.% or more, 1.5 wt.% to 10 wt.%, 1.5 wt.% to 8 wt.%, or 1.5 wt.% to 5 wt.%. The isocyanate-reactive component (or B-side) includes one or more polyetheramines. In some cases, the isocyanate-reactive components may include a mixture of high molecular weight and low molecular weight polyetheramines. High molecular weight (high MW) polyether amines may have a number average molecular weight of 3000 Da or more, such as 3100 Da or more, 3500 Da or more, or in a range of 3000 Da to 10,000 Da, or 3100 Da to 10,000 Da. Low molecular weight (low MW) polyether amines may have a number average molecular weight of 3000 Da or less, such as 2900 Da or less, 2500 Da or less, or in a range of 250 Da to 3000 Da, or 500 Da to 2900 Da. For example, the one or more polyetheramines of the isocyanate-reactive component can include at least one high molecular weight polyether amine having a functionality of 2.5 to 3.5 and a number average molecular weight of 3000 Da or more; and at least one low molecular weight polyether amine having a functionality of 2.5 to 3.5 and a number average molecular weight of 3000 Da or less. High MW polyetheramines and low MW polyetheramines may independently be selected from polyetheramines having an amine functionality in the range of 1.5 to 4, 2 to 4, or 2.5 to 3.5. The molar ratio of high MW:low MW polyetheramines may be in the range of 10:1 to 1:10, 5:1 to 1:5, or 3:1 to 1:3. Suitable polyetheramines include resins made from an appropriate initiator to which lower alkylene oxides, such as ethylene oxide, propylene oxide, butylene oxide or mixtures thereof are added, with the resulting hydroxyl-terminated polyol then being aminated. When two or more oxides are used, they may be present as random mixtures or as blocks of one or the other polyether. In the amination step, the terminal hydroxyl groups in the polyol may be primary or secondary hydroxyl groups. Reductive amination processes are known and described in U.S. Patent 3,654,370. Polyetheramines may include commercially available amines such as primary aliphatic JEFFAMINE™ series of polyether amines 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. In some embodiments, the isocyanate-reactive component may include at least one polyetheramine present at a percent by weight of the isocyanate-reactive component (wt.%) from 0.1 wt.% to 40 wt.%, 0.2 wt.% to 30 wt.%, or 0.25 wt.% to 15 wt.%. In formulations containing mixtures of high MW and low MW polyetheramines, wt.% ranges may be applied to each type of polyetheramine independently or as a combined total. Isocyanate-reactive components may include a thermally conductive filler present at a percent by weight (wt.%) of 50 wt.% to 95 wt.%, 75 wt.% to 94 wt.%, or 80 wt.% to 92 wt.%. Thermally conductive compositions disclosed herein may further include one or more internal mold release (IMR) agents present in one or more of the isocyanate component and the isocyanate reactive component. IMR agents may include branched fatty acids and branched fatty acid esters. IMR agents may include esters prepared from the reaction of a polyol having two or more hydroxyl groups with one or more equivalents of a fatty acid (e.g., monoester, diester, triester, etc.). IMR agents may have the general formula of R1(OH)n-x(OC=OR2)x, where R1is a branched (i.e., containing one or more secondary and / or tertiary carbons) C3 to C10 carbon chain polyol having n hydroxy functional groups, such as 2 or more, 3 or more, or in a range of 2 to 8; R2is a linear or branched, saturated or unsaturated C8 to C20 carbon chain; and x is an integer from 1 to 4, or 1 to 3. IMR agents disclosed herein may be prepared from the reaction of one or more equivalents of fatty acid(s) with a branched C3 to C10 polyol. Examples of suitable IMRs include, but are not limited to, neopentyl glycol, trimethylol ethane, trimethylol propane, trimethylol butane, di- (trimethylol propane), tri- (trimethylol propane), pentaerythritol, di- (pentaerythritol), tri- (pentaerythritol), and the like. Suitable fatty acids include one or more of C8 to C20 saturated fatty acids such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, sebacic acid, and the like; C8 to C20 unsaturated fatty acids such as palmitoleic acid, oleic acid, or caproleic acid, synthetic or naturally derived fatty acids such as soya oil acid, lauric acid, cocinic acid, eleostearic acid, tung oil fatty acid, linseed oil fatty acid, castor oil fatty acid, dimers or oligomers thereof, and the like. In some cases, IMR agents may include trimethylolpropane oleate or pentaerythritol oleate. IMR agents may be mixed into at least one of the isocyanate component or the isocyanate-reactive component at a percent by weight of the respective component (wt.%) in an amount ranging from 0.1 wt.% to 20 wt.%, 0.5 wt.% to 16 wt.%, or 1 wt.% to 15 wt.%. For the various embodiments, the thermally conductive composition may also include additives such as one or more plasticizers and thermally conductive fillers. For example, thermally conductive compositions disclosed herein may include one or more plasticizers to reduce the squeeze force required to assemble the components with the thermally conductive composition. Plasticizers may include, organic plasticizers, such as those containing carboxylic acid ester(s), phthalate(s), carboxylates, adipates, or a combination thereof. Specific examples include bis(2-ethylhexyl)terephthalate, bis(2-ethylhexyl)-1,4- benzenedicarboxylate, 2-ethylhexyl methyl-1,4-benzenedicarboxylate, 1,2 cyclohexanedicarboxylic acid, dinonyl ester (branched and linear), bis(2- propylheptyl)phthalate, diisononyl adipate, dioctyl adipate and combinations thereof. For the various embodiments, the thermally conductive composition may include the one or more glycol ether ester plasticizers at a percent by weight (wt.%) of the isocyanate component and / or the isocyanate-reactive component ranging from 1 wt.% to 20 wt.%. Glycol ether ester plasticizers may be mixed into at least one of the isocyanate component or the isocyanate-reactive component at a percent by weight of the respective composition (wt.%) in an amount ranging from 1 wt.% to 20 wt.%, 2 wt.% to 16 wt.%, or 4 wt.% to 15 wt.%. Plasticizers disclosed herein include various types of glycol ether esters including mixtures of one or more types. Suitable glycol ether esters include monoesters such as those described by Formula (I): wherein R1is a saturated, chain including 2 to 12 carbon atoms, R2 is either hydrogen or methyl, R3 is a saturated, unsaturated, and / or substituted carbon chain including 2 to 12 carbon atoms, and n is an integer ranging from 1 to 4. Glycol ether esters disclosed herein may also include those described by Formula (II): wherein R1 carbon chain including 2 to 12 carbon atoms, R2is either hydrogen or methyl, R3is a saturated, unsaturated, and / or substituted carbon chain including 2 to 12 carbon atoms, and n is an integer ranging from 1 to 4. Suitable glycol ether ester plasticizers include bis(2-(2- butoxyethoxy)ethyl) adipate, bis-dipropylene glycol n-butyl ether adipate, bis- diethylene glycol n-butyl ether malonate, bis-diethylene glycol n-butyl ether glutarate, bis- dipropylene glycol methyl ether maleate, tetraetyleneglycol di-2-ethylhexanoate, and the like. Glycol ether esters disclosed herein may also include those described by Formula (III):

[0002] wherein R1and R3are, independently, a saturated, unsaturated, and / or substituted carbon chain including 2 to 12 carbon atoms, R2is either hydrogen or methyl, and n is an integer ranging from 1 to 4. Suitable plasticizers also include glycol ether esters prepared from the esterification of a glycol ether with one or more equivalents of a carboxylic acid. Glycol ethers may include 1 to 4 repeats of one or more glycol units, including ethylene glycol, propylene glycol, and the like. Carboxylic acids may include C2 to C12 carboxylic acids such as acetic acid, propanoic acid, isobutanoic acid, adipic acid, 2-ethylhexanoic acid, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and the like. Carboxylic acids may include mono carboxylic acids and dicarboxylic acids. Examples of suitable plasticizers include 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 tetraethyleneglycol di-2-ethylhexanoate, propylene glycol methyl ether acetate, and the like. In one embodiment, one or more plasticizers are selected from a group consisting of bis-dipropylene glycol n-butyl ether adipate, triethylene glycol-di-2 ethylhexanoate, bis(2-(2- butoxyethoxy)ethyl) adipate, and tetraethyleneglycol di-2-ethylhexanoate or a combination thereof. Thermally conductive compositions may also include one or more thermally conductive fillers in the A-side and / or the B-side. 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, and may have a thermal conductivity of less than 1000 W / m•K, or less than 100 W / m•K. Fillers disclosed herein may have low density and hardness to reduce overall weight of the composition and reduce weight in automotive, EV, and reduce abrasiveness of the composition. In one embodiment, the filler density is < 6 gm / cc, < 4 gm / cc, or < 2.5 gm / cc. 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 mainly silicates, and aluminum silicates. Suitable fillers include aluminum trihydrate (ATH), natural or synthetic aluminum oxide, quartz, silica, and the like. For example, the thermally conductive filler is aluminum trihydrate. Thermally conductive compositions may include one or more fillers, which are either added into the formulation in their end state or formed in-situ. The thermally conductive fillers of the present disclosure can be modified with a treating agent before incorporation in the A-side and / or B-side of the thermally conductive composition that alter the hydrophobicity / hydrophilicity of the surface of a thermally conductive filler, modifying filler and polymer interaction, viscosity, and / or squeeze force of the resulting thermally conductive composition. Treatment agents may include fatty acids, silane treating agents, titanates, zirconates, aluminates, or silazane compounds. Thermally conductive filler disclosed herein may have a broad particle size distribution and / or have a bimodal particle size distribution. The average D50particle size for fillers disclosed herein may be in the range of from 0.05 μm to 500 μm, from 0.1 μm to 300 μm, from 0.5 μm to 100 μm, or from 0.5 μm to 50 μm. The average D90particle size for fillers disclosed herein may be in the range of from 0.05 μm to 500 μm, 1 μm to 300 μm, 5 μm to 200 μm, or 10 μm to 150 μm. The average D10 particle size for fillers disclosed herein may be in the range of from 0.05 μm to 30 μm, 0.08 μm to 10 μm, 0.1 μm to 10 μm. The span may be controlled in some cases to reduce the squeeze force of the resulting thermally conductive composition. Thermally conductive filler disclosed herein may have a broad particle size characterized by span of greater than 2, greater than 3, or greater than 4, or less than 50. In some cases, thermally conductive fillers may have a bimodal particle size distribution produced by blending two fillers with one filler having D50 in the range of 0.1 to 20 μm and another filler having D50in the range of 10 to 200 μm. Thermally conductive filler disclosed herein may be present at a percent by weight of the total weight of the thermally conductive composition (wt.%) of 50 wt.% to 95 wt.%, 75 wt.% to 94 wt.%, or 80 wt.% to 92 wt.%. The filler may be loaded in the A-side and / or B- side in equal or differing amounts that, when combined, result in a thermally conductive composition having a filler concentration within any of the above ranges. It should be noted that different filler sizes / types could be blended to obtain the desired filler loading and viscosity of a formulation. In some cases, thermally conductive filler may be an aluminum trihydrate. Thermally conductive filler may have a span >4, D10in the range of 0.1 to 10 microns, D50in the range of 5 to 50 microns, and D90 in the range of 50 to 200 microns. Thermally conductive compositions may include one or more antioxidants, including phenol-based antioxidants such as sterically hindered phenols, sterically hindered phenyl phosphites, and the like; sulfur-based antioxidants, phosphorus-based antioxidants, amine- based antioxidants, and the like. Suitable antioxidants include phenolic antioxidants, such as octadecyl 3-(3,5-ditert-butyl-4-hydroxyphenyl)propanoate, di-octadecyl-3,5-di-tert-butyl-4- hydroxyhydrocinnamate, benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy-, 2,2- bis(((3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoyl)oxy)methyl)propane-1,3-diyl bis(3- (3,5-di-tert-butyl-4-hydroxyphenyl)propanoate, tertiary butyl phenyl phosphate, and the like. Antioxidants may include commercially available antioxidants such as the IRGANOX®and IRGAFOS®series antioxidants from BASF. Antioxidants may be added to the isocyanate component and / or the isocyanate- reactive component at a percent by weight (wt.%) ranging from 0.05 wt.% to 5 wt.%, or 0.1 wt.% to 4 wt.%. Thermally conductive compositions may include one or more additives that can include moisture scavengers (e.g., zeolites, molecular sieves, p-toluene sulfonylisocyanate), adhesion promoters, thixotropic agents, color agents such as dyes or pigments, wetting agents such as surfactants, filler dispersion agents, thickening agents, compatibilizers, anti-settling agents, anti-syneresis agents, flame retardants, and / or filler treatment agents. Prior to combining to form a thermally conductive composition, the isocyanate component and / or the isocyanate-reactive component may have a squeeze force of 250 N or less, 150 N or less, or 100 N or less. The isocyanate component and / or the isocyanate- reactive component may have a squeeze force in the range of 35 N to 250 N, 35 N to 150 N, or 35 N to 100 N. The thermally conductive composition of the present disclosure can also include additional optional components as are known in the art. Such additional optional components can include, but are not limited to moisture scavengers (e.g., zeolites and / or molecular sieves), adhesion promoters, thixotropic agents, color agents such as dyes, wetting agents such as surfactants, filler treatment agents such as silanes and BYK surface treatment additives. Preparation of the thermally conductive compositions of the present disclosure may be achieved by combining (e.g., mixing) the isocyanate component and the isocyanate- reactive component and curing the resulting thermally conductive composition as provided herein. Combining the isocyanate component and the isocyanate-reactive component can be done in any sequence to combine the components to prepare the final mixture. Suitable mixing techniques include the use of a Ross PD Mixer (Charles Ross), Myers mixer, FlackTek Speedmixer, butterfly mixer and the like. Various components of the composition could also be mixed using a continuous process such as twin-screw extrusion. Various streams could be fed separately to an extruder or premixed in various combinations to form the blocked isocyanate composition and the isocyanate-reactive component. Such a process could be suitable for large volume manufacturing. The isocyanate-reactive component and the isocyanate component can be combined such that the molar ratio of blocked isocyanate groups to amine reactive groups is in the ranges of 0.90:1.1 to 1.1:0.9, such as 0.90:1.1, 0.95:1.05, 0.97:1.03, or 1:1. At the same time, the volume ratio of the isocyanate-reactive component to the isocyanate component in the curable composition may be controlled within the range between 0.90:1.1 from 0.95:1.05, from 0.97:1.03, or at the ratio of 1:1. The mixture of isocyanate component and isocyanate-reactive component may be cured at a temperature from 0oC to 60oC, 10oC to 50oC, 15oC to 45oC, or 18oC to 35oC (e.g., RT). Curing may be indicated by increase in the viscosity after mixing A-side and B- side, with the eventual formation of a cured thermally conductive solid with a measurable hardness. For the various embodiments, the thermally conductive composition has a Shore 00 hardness of greater than 60 after 10 days cure at 25 ⁰C. For example, the thermally conductive composition may have a range of hardness as determined by ASTM D-2240-15 in a range of 60 to 90 Shore OO, 60 to 85 Shore OO, or 60 to 80 Shore OO. In some embodiments, the thermally conductive compositions have a cured hardness as determined by ASTM D-2240-15 of 60-85 Shore OO. Cured thermally conductive compositions may have a thermal conductivity > 0.5 W / m•K, or > 1 W / m•K, or most preferably > 1.5, W / m•K, or < 50 W / m•K. Cured thermally conductive compositions disclosed herein 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 A-side and B-side allows for easy processing of the material. Thermally conductive compositions disclosed herein may be useful as a thermal interface material for energy storage devices and in electronic vehicle battery thermal management. In some cases, the compositions may include gap fillers and adhesives that are applied between a heat source and a heat sink to provide a thermally conductive interface, such as between a battery cell / module and a cooling plate. Manual or automatic dispensing tools can be used to apply the thermally conductive compositions directly to the target surface to minimize waste. In an embodiment, a thermally conductive composition may be prepared by combining the isocyanate component and the isocyanate-reactive component, as discussed herein, and applying to a cooling plate or heat sink using an automated mix-meter-dispense system, followed by installation of a battery cell, module or pack, or other heat source. For example, in an embodiment the thermally conductive composition may be prepared by combining the isocyanate component and the isocyanate-reactive component, as discussed herein, and emplacing the thermally conductive composition between a heat source and a heat sink in an EV battery. Additionally, thermally conductive compositions may be used to form pre-cured articles such as thermal interface gap pads. In one example, pre-cured articles may be formed by curing thermally conductive compositions at a desired thickness, cutting the article to a desired shape, and then compressed to fix in place as needed. In some cases, cured articles may also help reduce vibration stress for shock dampening. Examples The following Examples (EX) and Comparative Examples (CE) are provided to illustrate the embodiments of the present disclosure but are not intended to limit the scope thereof. All parts and percentages are by weight unless otherwise indicated. Table 1 lists the materials used in the following EX and CE. All materials were purchased from commercial vendors and used as received unless otherwise noted. Table 1 - Materials Material Description Toluene diisocyanate (TDI). A 80:20 mixture of 24 and h a y Blocked Isocyanate Cardanol blocked TDI-based prepolymer made with 9:1 Prepolymer-5 weight ratio of Polyol-1 and Polyol-2 with about 3.5% NCO b f bl ki s Prepolymer viscosity was measured using a cone and plate setup at 25 C and 10 sec-1with an AR2000 Rotational Rheometer (TA Instruments, New Castle, DE) in which the indicated material was placed between an 80 mm diameter Peltier Plate (with hardened chrome surface, TA instruments) and a 40 mm, 2 degree cone rotating at a constant angular velocity while the Peltier plate remained at rest, and running a temperature sweep from 25 to 50 °C at a ramp rate of 3 °C / min at a shear rate of 10 sec-1. Blocked Isocyanate Prepolymer 2-5 Synthesis Blocked Isocyanate Prepolymer 2 An equal weight ratio (1:1) of Polyol-1 and Polyol-2 was dried at 70 ⁰C with N2sparge to obtain a dry polyol mixture having about 200 ppm water. 433 grams of the dry polyol mixture was charged into a reactor having overhead stirring, N2purge, thermocouple, and heating mantle. About 0.04 grams of benzoyl chloride was added to the dry polyol mixture to neutralize the polyol. The polyol mixture was stirred at 300-500 RPM and 67 grams of VORONATE™ T-80 was added. The mixture was slowly heated to 75-80oC after which it was allowed to digest for about 2.0 hours to form an NCO TDI Prepolymer. 445.8 grams of the TDI Prepolymer was charged in 1000 ml dry reactor having overhead stirring, N2purge, thermocouple, and heating mantle. TDI Prepolymer was heated to 75-80oC with stirring and about 2000 ppm of Catalyst-1 and 82 grams of Cardanol were charged in 2 to 3 doses into the reactor (Eq. ratio of TDI prepolymer to Cardanol = 1.0:0.95). The contents of the reactor were allowed to react for 2 hours after which the isocyanate concentration was analyzed using FT-IR. 1.0 wt. % MPEG was added to the resulting blocked isocyanate prepolymer, and the mixture was stirred and allowed to digest at 75-80oC for 1 hour. An additional 500 ppm of Catalyst-1 was charged, and blocking was allowed to occur for an additional 1 hour after which the blocking to produce the blocked isocyanate prepolymer 2 was deemed to be complete. Blocked Isocyanate Prepolymer 3 A 3:1 weight ratio of Polyol-1 and Polyol-2 was dried at 70 ⁰C with N2sparge to obtain a dry polyol mixture having about 200 ppm water. 421 grams of the dry polyol mixture was charged into a reactor having overhead stirring, N2purge, thermocouple, and heating mantle. About 0.04 grams of benzoyl chloride was added to the dry polyol mixture to neutralize the polyol. The polyol mixture was stirred at 300-500 RPM and 67 grams of VORONATE™ T-80 was added. The mixture was slowly heated to 75-80oC after which it was allowed to digest for about 2.0 hours to form an NCO TDI Prepolymer. 449.9 grams of the TDI Prepolymer was charged in 1000 ml dry reactor having overhead stirring, N2purge, thermocouple, and heating mantle. The TDI Prepolymer was heated to 75-80oC with stirring and about 1500 ppm of Catalyst-1 and 101.5 grams of Cardanol were charged in 2 to 3 doses into the reactor (Eq. ratio of TDI prepolymer to Cardanol = 1.0:0.95). The contents of the reactor were allowed to react for 2 hours. 1.0 wt. % MPEG was added to the resulting blocked isocyanate prepolymer, and the mixture was stirred and allowed to digest at 75-80oC for 1 hour. An additional 900 ppm of Catalyst-1 was charged, and blocking was allowed to occur for an additional 1 hour after which the blocking to produce the blocked isocyanate prepolymer 3 was deemed to be complete. Viscosity = 31.58 Pa. S at 25 ⁰C ambient temperature. Blocked Isocyanate Prepolymer 4 Polyol-2 was dried at 70 ⁰C with N2sparge to obtain a dry polyol mixture having about 200 ppm water. 439.8 grams of the dry polyol mixture was charged into a reactor having overhead stirring, N2purge, thermocouple, and heating mantle. About 0.04 grams of benzoyl chloride was added to the dry polyol mixture to neutralize the polyol. The polyol mixture was stirred at 300-500 RPM and 62.5 grams of VORONATE™ T-80 was added. The mixture was slowly heated to 75-80oC after which it was allowed to digest for about 2.0 hours to form an NCO TDI Prepolymer. 421 grams of the NCO TDI Prepolymer was charged in 1000 ml dry reactor having overhead stirring, N2purge, thermocouple, and heating mantle. The NCO TDI Prepolymer was heated to 75-80oC with stirring and about 800 ppm of Catalyst-1 and 89 grams of Cardanol were charged in 2 to 3 doses into the reactor (Eq. ratio of TDI prepolymer to Cardanol = 1:0.95). The contents of the reactor were allowed to react for 2 hours after which the blocking to produce the Blocked Isocyanate Prepolymer 4 was deemed to be complete. Viscosity = 71.59 Pa. S at 25 ⁰C. Blocked Isocyanate Prepolymer 5 Polyol-1 and Polyol-2 were dried at 70 ⁰C with N2sparge to obtain a dry polyol mixture having about 200 ppm water. 72.38 grams of VORONATE™ T-80 was charged in the dry reactor having overhead stirring, N2purge, thermocouple, and heating mantle. About 0.04 grams of benzoyl chloride was added. Then 43 grams of polyol 2 was charged into a reactor and held at ambient temperature for 30 minutes. Then 385 grams of Polyol-1 was charged. The mixture was slowly heated to 75-80 ⁰C after which it was allowed to digest for about 2.0 hours to form an NCO TDI Prepolymer. 463 grams of the NCO TDI Prepolymer was charged in 1000 ml dry reactor having overhead stirring, N2purge, thermocouple, and heating mantle. The NCO TDI Prepolymer was heated to 75-80 ⁰C with stirring and about 1000 ppm of Catalyst-1 and 106 grams of Cardanol were charged in 2 to 3 doses into the reactor (Eq. ratio of TDI prepolymer to Cardanol = 1.0:0.95). The contents of the reactor were allowed to react for 2-4 hours. 1.0 wt. % MPEG was added to the resulting blocked isocyanate prepolymer, and the mixture was stirred and allowed to digest at 75-80 ⁰C for an additional 1-2 hours after which the blocking to produce the blocked isocyanate prepolymer 5 was deemed to be complete. Viscosity = 27.5 Pa. S at 25 ⁰C. % NCO after blocking for Blocked Isocyanate Prepolymer 2-5 % NCO after blocking was found to be less than 0.5% for all the blocked prepolymers. Thermal Interface Material (TIM) EX and CE of the TIM were prepared from a two-part system that included Part A and Part B. For the preparation Part A and Part B of the TIM formulations, individual components were added in a cup and mixed using a high-speed mixer. Liquid components of the formulation were added first and mixed at 2000 rpm / 30 seconds, followed by addition of solid fillers which were mixed at 2000 rpm / 30 seconds, then hand mixed and mixed again at 2000 rpm / 30 seconds. For curing the two-part system, Part A and Part B were mixed in 1:1 weight ratio in a cup and mixed using a high-speed mixer and allowed to cure at ambient conditions (23oC). Hardness was measured using a Shore OO durometer per ASTM D2240. Table 2- Composition of Part A and Part B and Properties of Cured TIM for EX-1, EX- 2 and CE-A EX-1, EX-2 & CE-A EX-1 EX-2 CE-A Antioxidant 1.00 Filler 212.00 212.00 212.00 211.00 Table 3- Composition of Part A and Part B and Properties of Cured TIM for EX-3 EX-3 EX-4 EX-3, EX-4 Total 250.00 250.00 250.00 Squeeze force [N] 202 113 59 , er 10 days curing at ambient conditions (23oC). The thermal conductivity of the EX and CE of the TIM was measured using the Hot Disk Thermal Constants Analyzer (TPS 2500S, Thermotest Instruments, Canada) per ISO 22007-2. All measurements are completed with a thermal probe using a double-sided measurement with two-6 mm cups, at 150 mW heating power and 5 second measurement time. Squeeze force was measured using a texture analyzer equipped with a 50 kg load cell. After dispensing the TIM onto a flat heavy-duty aluminum substrate, an acrylic probe with a diameter of 40 mm was lowered to sandwich the TIM material against the flat substrate to achieve a standard 5.0 mm gap thickness. Any excess overflow TIM material was trimmed away with a flat-edge spatula. After trimming, the test started and the probe moved to a final thickness of 0.3 mm, at a rate of 1.0 mm / sec while the force was recorded. The specific force value recorded at the gap of 0.5 mm is reported as the “squeeze force.” Results CE-A shows that when no amine-initiated polyol is used, curing kinetics is very slow with Shore OO hardness less than 60 after 10 days. EX-1, EX-2, EX-3 and EX-4 show that when an amine-initiated polyol is used in the prepolymer, fast curing kinetics can be achieved with Shore OO hardness of greater than 60 in less than 10 days. While the foregoing is directed to exemplary embodiments, other and further embodiments may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

What is Claimed is:

1. A thermally conductive composition, comprising: an isocyanate component comprising: a blocked isocyanate prepolymer formed from a reaction of: (a) a first prepolymer prepared from the reaction of one or more polyols comprising an amine-initiated polyol and a polyisocyanate, wherein the amine-initiated polyol has a hydroxyl number of 20 to 1,000; and (b) an alkyl phenol, wherein the first prepolymer and the alkyl phenol are reacted in an equivalent ratio of 1:0.9 to 1:1.1 (first prepolymer:alkyl phenol) to form the blocked isocyanate prepolymer; and an isocyanate-reactive component comprising one or more polyetheramines; and one or more thermally conductive fillers present in one or more of the isocyanate component and the isocyanate-reactive component.

2. The composition of claim 1, wherein the reaction of (a) the amine-initiated polyol and the polyisocyanate further includes a polypropylene oxide containing polyol, wherein the polypropylene oxide containing polyol and the amine-initiated polyol are present in the reaction mixture at a weight ratio in the range of 0.98:0.2 to 0.2:0.98 (polypropylene oxide containing polyol:amine-initiated polyol).

3. The composition of any one of claims 1-2, wherein the amine-initiated polyol is formed using a tri-amine initiator.

4. The composition of any one of claims 1-3, wherein the amine-initiated polyol is formed using a bis-3-aminopropylmethylamine initiator.

5. The composition of any one of claims 1-4, wherein the polyisocyanate is a toluene diisocyanate.

6. The composition of any one of claims 1-5, wherein the alkyl phenol is cardanol.

7. The composition of any one of claims 1-6, wherein the blocked isocyanate prepolymer has a % NCO of at least 2 % before blocking.

8. The composition of any one of claims 1-7, further including an alkylalkoxysilane comprising an alkyl chain of C12 or more present at a percent by weight (wt.%) of 1.5 wt.% or more based on the weight of the isocyanate component.

9. The composition of any one of claims 1-8, further including one or more glycol ether ester plasticizers at a percent by weight (wt.%) of the isocyanate component and / or the isocyanate-reactive component ranging from 1 wt.% to 20 wt.%.

10. The composition of any one of claims 1-9, wherein the one or more polyetheramines comprise: at least one high molecular weight polyether amine having a functionality of 2.5 to 3.5 and a number average molecular weight of 3000 Da or more; and at least one low molecular weight polyether amine having a functionality of 2.5 to 3.5 and a number average molecular weight of 3000 Da or less.

11. The composition of any one of claims 1-10, wherein the thermally conductive filler is aluminum trihydrate (ATH).

12. The composition of any one of claims 1-11, further including a monofunctional polyethylene glycol.

13. The composition of any one of claims 1-12, wherein the thermally conductive composition has a Shore 00 hardness of greater than 60 after 10 days cure at 25 ⁰C.

14. A thermal interface material prepared by combining the isocyanate component and the isocyanate-reactive component and curing the resulting thermally conductive composition of any one of claims 1 to 13.

15. A method of using the composition of any one of claims 1 to 13, the method comprising combining the isocyanate component and the isocyanate-reactive component; and emplacing the thermally conductive composition between a heat source and a heat sink in an EV battery.

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