Two-part interface material, system including the interface material and method thereof

Abstract

The teachings herein relate to new compositions for thermal interface materials that provide improved thermal conductivity without the need for expensive or abrasive filler materials. Improved thermal conductivity is achieved using a combination of increased filler loading, selection of fillers with a wide particle size distribution, and selection of non-abrasive fillers. The thermal interface material preferably has a specific gravity of about 4.0 or less, about 3.0 or less, about 2.5 or less, or about 2.4 or less. The thermal interface material can be a two-part composition. In order to achieve maximum thermal conductivity, each part preferably contains a liquid matrix material and a dispersed filler. After mixing, the first and second parts can react to increase viscosity (e.g., by polymerization and / or crosslinking). The first part preferably contains a carbamate-containing compound that reacts with a carbamate-reactive compound (which is preferably in the second component). The first part is preferably substantially or completely free of isocyanate-containing compounds because these compounds may reduce the shelf life stability of the composition. The carbamate-reactive compound is preferably a polyamine that contains two or more spaced amine groups. The first part, the second part, or both preferably contain a catalyst for accelerating the reaction between the carbamate-containing compound and the carbamate-reactive compound.

Description

Technical Field

[0001] The teachings herein relate to thermal interface materials that generally have high thermal conductivity, parts and articles including the thermal interface materials, and related methods. The thermal interface materials are preferably formed from a two-part composition, wherein each part includes a matrix phase that is liquid at room temperature and one or more thermally conductive fillers dispersed in the matrix phase. The matrix phase of the first part preferably includes a carbamate-containing compound, and the matrix phase of the second part preferably includes a carbamate-reactive compound. Background Art

[0002] The automotive industry has seen a trend to reduce the weight of vehicles over the past decade. This lightweight trend is mainly driven by regulations to reduce CO2 emissions from vehicle fleets. In recent years, the increasing number of electrically driven vehicles has further stimulated lightweight construction strategies. The combination of a growing automotive market and a growing market share for electric vehicles has led to a strong growth in the number of electrically driven vehicles. In order to provide a long driving range, batteries with a high energy density are required. Currently, several battery strategies follow different detailed concepts, but what all long-range and durable battery concepts have in common is the need for thermal management. In particular, in order to thermally connect a battery cell or module to a cooling unit, a thermal interface material based on a two-part reactive composition is required.

[0003] Various compositions including conductive fillers and two-part reactive compositions are described in PCT patent application numbers WO2001 / 041213 A1; WO 2014 / 047932 A1; WO 2015 / 148318 A1; WO 2016 / 145651 A1; WO 2017 / 091974 A1; WO 2018 / 34721: and WO 2006 / 016936 A1; European patent application EP 1438829 A1; Japanese patent application JP 2010 / 0138357 A; and U.S. patent application US 2009 / 0250655 A1; each of which is incorporated herein by reference in its entirety. In these previous attempts, the compositions suffered from one or more of the requirements for an affordable thermal interface material, such as the thermal conductivity of the composition was insufficient, the composition was difficult to produce, the composition did not properly fill gaps such that contact was insufficient; the components of the composition did not react at room temperature, one or both of the components had poor shelf life stability, the composition required expensive materials; or the composition required abrasive fillers that could damage processing equipment.

[0004] There continues to be a need for thermal interface materials (and particularly two-part compositions) having both high thermal conductivity and low viscosity. There continues to be a need for thermal interface materials having filler materials that are non-abrasive. There continues to be a need for thermal interface materials that are more economical in terms of raw material costs and / or manufacturing / processing costs. There also continues to be a need for two-part compositions with high filler content that can flow at room temperature to fill gaps. There also continues to be a need for materials that meet one or more of the above needs, which also have one or more of the following characteristics: storage stability (e.g., maintaining the ability to flow at room temperature after aging); the ability to react at room temperature to polymerize, crosslink, or both; good thermal conductivity; substantially or completely avoid the use of abrasive fillers; or are lightweight (e.g., having a specific gravity of about 3 or less, about 2.8 or less, about 2.6 or less, about 2.5 or less, or about 2.4 or less). Summary of the invention

[0005] One or more of the above needs may be achieved using thermal interface materials according to the teachings herein.

[0006] A first aspect of the teachings herein relates to a two-part composition for a thermal interface material, the two-part composition comprising: a first part comprising at least one prepolymer comprising two or more urethane groups; and a second part comprising at least one or more polyamine compounds capable of reacting with the prepolymer. The composition preferably comprises (in the first part, the second part, or both) one or more catalysts for catalyzing the reaction between the prepolymer and the polyamine compound; and 50 weight percent or greater of one or more conductive fillers based on the total weight of the two-part composition.

[0007] A second aspect of the present invention is a method comprising the steps of arranging a layer of thermal interface material according to the present invention between a first component and a second component, and applying pressure so that the thermal interface material contacts both the first component and the second component and fills the gap between the two components. DETAILED DESCRIPTION

[0008] The first aspect may be further characterized by one or any combination of the following features: the prepolymer is formed by capping one or more isocyanate groups (preferably substantially each or all of each isocyanate group) of an aromatic polyisocyanate prepolymer with a phenolic group of a capping compound; the capping compound comprises a terminal phenolic group (preferably a single terminal phenolic group) attached to a linear hydrocarbon (preferably a linear hydrocarbon comprising 6 or more, 8 or more, 10 or more, or 12 or more carbon atoms) (preferably a linear hydrocarbon comprising 60 or less, 30 or less, or 20 or less carbon atoms); the one or more polyamines, the prepolymer, or both have an average functionality greater than 2; the one or more thermally conductive fillers are preferably The first part comprises 75 weight percent or more of a thermally conductive filler, which is preferably selected from aluminum hydroxide, aluminum oxide, aluminum powder, zinc oxide, boron nitride, and a mixture of these; the second part comprises 75 weight percent or more of a thermally conductive filler, which is preferably selected from aluminum hydroxide, aluminum oxide, aluminum powder, zinc oxide, boron nitride, and a mixture of these; preferably, the surface of the thermally conductive filler (such as aluminum hydroxide) is partially or completely coated with a surface modifier for reducing the hydrophilicity of the surface; the composition comprises a thermally conductive filler, which is preferably selected from aluminum hydroxide, aluminum oxide, aluminum powder, zinc oxide, boron nitride, and a mixture of these having a D of about 3 or greater 90 / D 50The composition preferably comprises one or more plasticizers; the composition preferably comprises a fatty acid or an ester of a fatty acid; the composition comprises an epoxy resin in the first part; the weight ratio of the prepolymer to the epoxy resin is about 0.5 or greater, more preferably about 0.8 or greater, even more preferably about 1.0 or greater; the weight ratio of the prepolymer to the epoxy resin is about 10 or less, about 5 or less, or about 4 or less; the composition is substantially free of isocyanate-containing compounds; the amount of NCO in the first part is about 0.10 weight percent or less, about 0.05 weight percent or less, or about 0.01 weight percent or less, based on the total weight of the first part; the urethane groups in the first part are The molar ratio of the amine groups in the second part is about 0.1 or greater, about 0.2 or greater, about 0.3 or greater, about 0.4 or greater, about 0.5 or greater, or about 0.6 or greater; the molar ratio of the carbamate groups in the first part to the amine groups in the second part is about and / or about 10 or less, about 5.0 or less, about 3.5 or less, about 2.5 or less, about 2.0 or less, or about 1.7 or less; the first part includes calcium carbonate; the amount of calcium carbonate in the first part and / or in the composition is about 0.1 weight percent or greater, preferably about 0.5 weight percent or greater, or about 1.0 weight percent or greater; the first part includes some or all of the catalyst; the composition is characterized in that according to ASTM 5470-12 has a thermal conductivity of about 2.0 W / mK or more, preferably about 2.5 or more, more preferably about 2.8 or more, even more preferably about 2.9 or more, and most preferably about 3.0 or more on a thermal interface material tester from ZFW Stuttgart, wherein the test is performed in Spaltplus mode at a thickness of 1.8-1.2 mm. The described thermal interface material is considered to be Type I (viscous liquid) as described in ASTM 5470-12. The upper contact is heated to about 40°C and the lower contact is heated to about 10°C, resulting in a sample temperature of about 25°C. When applied from a manual cartridge system, the A and B components are mixed with a static mixer; the two-part composition cures at room temperature (preferably, characterized by an increase in the push-in force of about 60% or more, or about 100% or more, after aging for 24 hours after mixing); the first part is storage stable (e.g., characterized by a push-in force of less than 700 N for the first part after aging for 3 days at 55°C); or the two-part composition is characterized by a specific gravity of about 2.5 or less.

[0009] Another aspect according to the teachings herein relates to an article comprising: a first component that generates heat, a second component for removing heat, and a layer of thermal interface material interposed between the first component and the second component, wherein the thermal interface material provides a path for transferring heat from the first component to the second component. The thermal interface material is preferably formed from a two-part composition according to the teachings herein.

[0010] Another aspect according to the teachings herein relates to a method comprising the steps of: placing a layer of thermal interface material between a first component and a second component and applying pressure so that the thermal interface material contacts both the first component and the second component and fills a gap between the two components. The thermal interface material is preferably formed from a two-part composition according to the teachings herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a graph illustrating characteristics of a composition of a filler (A) having a generally narrow particle size distribution, a composition of a filler (B) having a generally broad particle size distribution, and a composition of a filler (C) having a generally broad particle size distribution that has been surface-modified.

[0012] Figure 2 is a graph illustrating the characteristics of the reaction between the surface modifier and the conductive filler. For example, the surface modifier can change the hydrophobicity of the surface.

[0013] Figure 3 is a graph showing illustrative compositions having different amounts of filler, wherein the filler (A) has a narrow particle size distribution; (B) has a wide particle size distribution, and (C) has a wide particle size distribution and a surface modifier to reduce or minimize bonding between the matrix phase material and the filler.

[0014] Figure 4 is an optical micrograph of an illustrative conductive filler having a broad particle size distribution.

[0015] Figure 5 is a diagram showing illustrative features of a device including a thermal interface material.

[0016] Figure 6 is an illustrative diagram of a battery including a thermal interface material.

[0017] Figure 7 is a diagram illustrating various chemical reactions that may be employed or avoided in accordance with the teachings herein. DETAILED DESCRIPTION

[0019] Unless otherwise indicated, the term "consisting essentially of includes amounts of about 90 weight percent or greater, about 95 weight percent or greater, about 98 weight percent or greater, or about 99 weight percent or greater.

[0020] Unless otherwise stated, the terms "conductive" and "conductivity" refer to "thermal conductivity" and "thermal conductivity."

[0021] The thermal interface material comprises two or more phases, and preferably comprises two phases. The first phase of the thermal interface material is a matrix phase. The matrix phase is preferably a continuous phase. However, the matrix phase can be a co-continuous phase and / or include one or more sub-phases. Preferably, the matrix phase comprises, consists essentially of, or consists entirely of: one or more polymers, oligomers, or polymerizable compounds. Preferably, the matrix phase comprises, consists essentially of, or consists entirely of: one or more materials that are liquid at room temperature or require minimal heating to become liquid. The second phase is a discrete phase dispersed in the matrix phase. It should be understood that the discrete phase can be coated with one or more additional phases that provide an interface between the discrete phase and the matrix phase. Typically, the matrix phase includes a material that generally has a low thermal conductivity (e.g., about 1 W / mK or less, or about 0.2 W / mK or less), so that the thermal conductivity of the composition depends primarily on the discrete phase. The discrete phase includes one or more filler materials that are solid at room temperature. Because the filler phase is required to provide a large amount of heat transfer, it is necessary to include a high concentration of filler to overcome the fact that the filler particles are generally dispersed in the matrix phase.

[0022] Thermal interface materials can be formed from a single composition, or can be formed by combining two or more parts each having a different composition. For example, a thermal interface material can be formed by mixing a first part (A-component) and a second part (i.e., B-component) of a two-part composition. Typically, after mixing, the matrix phase of the composition is formed by combining the matrix phases of each part. The combined matrix phase is preferably reactive so that the molecular weight of one or more compounds in the matrix phase increases. As an example, the compound in the first part can react with the compound in the second part. As another example, the reaction of the compound in the first part can be accelerated by a catalyst in the second part. The reaction can be any reaction that increases the viscosity of the matrix phase. Preferably, the reaction includes a polymerization reaction, a cross-linking reaction, or both. In some applications, the thermal interface material is contacted with a temperature-sensitive component, and it is desirable to avoid heating the component to a temperature at which it may deteriorate or lose performance. Preferably, the reaction can be carried out at a reaction temperature of about 50°C or less, about 40°C or less, about 30°C or less, or about 23°C or less. Preferably, the reaction can be carried out at a reaction temperature of about -10 ° C or higher, about 0 ° C or higher, or about 10 ° C or higher. For example, the reaction can occur at about room temperature (for example, about 23 ° C). If the reaction is exothermic, the temperature rise caused by the released energy is typically about 30 ° C or lower, about 20 ° C or lower, or about 10 ° C or lower. In some applications, it is desirable that the reaction occurs quickly (for example, in about 1 hour or less). However, it is preferred that the reaction is carried out for a long time period so as to avoid a sharp increase in temperature. Preferably, the reaction time can be about 30 minutes or longer, more preferably about 1 hour or longer, even more preferably about 4 hours or longer, even more preferably about 8 hours or longer, and most preferably about 24 hours or longer. The reaction time is typically about 30 days or shorter, about 15 days or shorter, or about 7 days or shorter.

[0023] When the thermal interface material is provided as a two-part composition, the two parts can be combined in any convenient volume ratio. The volume ratio of the first part to the second part can be about 100:1 or less, about 10:1 or less, about 3:1 or less, about 2:1 or less, or about 1:1 or less. The volume ratio of the first part to the second part can be about 1:100 or greater, about 1:10 or greater, about 1:3 or greater, about 1:2 or greater, or about 1:1 or greater. The first part and the second part can be packaged separately. The first part and the second part can be packaged in a single container, typically the two parts are separated to avoid contact and / or mixing before use.

[0024] Due to the fillers in the composition, the thermal interface material typically has a specific gravity of about 1.50 or greater, or about 1.8 or greater. In some applications, such as in transportation, it is desirable that the thermal interface material be lightweight. Preferably, the thermal interface material has a specific gravity of about 4.0 or less, more preferably about 3.0 or less, even more preferably about 2.5 or less, even more preferably about 2.4 or less, and most preferably about 2.3 or less.

[0025] filler

[0026] Compositions according to the teachings herein include one or more fillers for increasing the thermal conductivity of the composition. Although fillers may include ultrahigh conductivity fillers (e.g., fillers having a thermal conductivity of about 100 W / mK), such fillers are typically abrasive and / or expensive. Preferably, the one or more fillers include, consist essentially of, or consist entirely of: one or more conductive fillers having a thermal conductivity of about 80 W / mK or less, about 50 W / mK or less, about 30 W / mK or less, about 20 W / mK or less, or about 15 W / mK or less. The conductive filler preferably has a thermal conductivity of about 3 W / mK or greater, about 4 W / mK or greater, about 5 W / mK or greater, or about 6 W / mK or greater. The conductive filler may be characterized by a thermal conductivity of about 10+ / -10%, about 10+ / -20%, or about 10+ / -30%. Preferably, the amount of ultrahigh conductivity filler in the composition is about 15 weight percent or less, more preferably about 4 weight percent or less, even more preferably about 1 weight percent or less, and most preferably about 0.3 weight percent or less, based on the total weight of the one or more fillers. The amount of ultrahigh conductivity filler in the composition may be about 0.0 percent or more, based on the total weight of the one or more fillers. The amount of conductive filler (i.e., other than the ultrahigh conductivity filler) may be about 80 weight percent or more, about 85 weight percent or more, about 90 weight percent or more, about 93 weight percent or more, about 96 weight percent or more, about 98 weight percent or more, about 99 weight percent or more, or about 99.7 weight percent or more, based on the total weight of the one or more fillers. The amount of conductive filler may be about 100 weight percent or less, based on the total weight of the one or more fillers.

[0027] The ultra high conductivity filler, if present, may be any filler having a thermal conductivity of about 100 W / mK. Examples of ultra high conductivity fillers include boron nitride and aluminum powder.

[0028] The conductive filler can be any filler having a thermal conductivity as described herein. For example, the conductive filler can have a thermal conductivity of about 3 W / mK to about 80 W / mK. The conductive filler is preferably non-abrasive (e.g., less abrasive than boron nitride, less abrasive than aluminum powder, or both). An example of a non-abrasive conductive filler is aluminum hydroxide (i.e., ATH) powder. Aluminum hydroxide powder has a thermal conductivity of 3 to 80 W / mK (typically about 10 W / mK).

[0029] Conductive fillers typically include one or more metal or metalloid atoms and one or more non-metal atoms. Metalloid atoms include boron, silicon, germanium, arsenic, antimony, and tellurium. Preferred metal atoms include alkali metals, alkaline earth metals, transition metals, and post-transition metals. The amount of non-metal atoms in the conductive filler should be high enough so that the conductive filler is not hard and abrasive. Examples of hard and abrasive fillers containing metals or metalloids include SiC, TiC, and BN. These hard and abrasive fillers include 50 atomic percent of metal or metalloid. Preferably, based on the total number of atoms in the conductive filler, the concentration of non-metal atoms in the conductive filler is greater than about 50 atomic percent, more preferably about 65 percent or more, even more preferably about 75 percent or more, and most preferably about 80 percent or more of non-metal atoms. The concentration of non-metal atoms can be about 95 atomic percent or less, about 93 atomic percent or less, about 90 atomic percent or less, or about 88 atomic percent or less. The conductive filler preferably has a sufficient concentration of metal atoms so that the thermal conductivity is about 3W / mK. The combined concentration of any metals and metalloids in the conductive filler is preferably about 5 atomic percent or greater. The combined concentration of any metals and metalloids in the conductive filler may be less than 50 atomic percent, about 35 atomic percent or less, about 25 atomic percent or less, or about 20 atomic percent or less.

[0030] Preferred compositions include a sufficient amount of conductive filler such that the thermal conductivity of the composition is about 1.5 W / mK or greater, preferably about 2.0 W / mK or greater, more preferably about 2.5 W / mK or greater, and most preferably about 3.0 W / mK or greater. The thermal conductivity of the composition measured on a thermal interface material tester from ZFW, Stuttgart, according to ASTM 5470-12 is typically about 10 W / mK or less, about 7 W / mK or less, or about 5 W / mK or less, wherein the test is conducted in Spaltplus mode at a thickness of 1.8-1.2 mm; the thermal interface material described is considered to be Type I (viscous liquid) as described in ASTM 5470-12, the upper contact is heated to about 40°C and the lower contact is heated to about 10°C, resulting in a sample temperature of about 25°C.

[0031] When applied from a manual cartridge system, the A and B components are mixed with a static mixer. If the amount of conductive filler is too low, the composition will not be sufficiently conductive to manage the temperature of the device. In order to achieve such a high thermal conductivity of the composition, the composition typically has a high concentration of conductive filler. Preferably, the amount of conductive filler in the composition is about 60 weight percent or greater, more preferably about 70 weight percent or greater, even more preferably about 75 weight percent or greater, even more preferably about 80 weight percent or greater, even more preferably about 85 weight percent or greater, and most preferably about 88 weight percent or greater, based on the total weight of the composition. The amount of conductive filler in the composition should be low enough so that the conductive filler can be dispersed in the matrix. Typically, the amount of conductive filler is about 95 weight percent or less, more preferably about 92 weight percent or less, based on the total weight of the composition.

[0032] The conductive filler preferably has a Mohs hardness low enough that it is generally non-abrasive. Preferably, the conductive filler has a Mohs hardness of about 7.0 or less, preferably about 5.0 or less, and more preferably about 4.0 or less. The conductive filler may have a Mohs hardness of about 0.5 or greater, about 1.5 or greater, or about 2.0 or greater.

[0033] Conductive fillers typically include MX bonds, where M is a metal and X is a non-metal. Preferably, the ratio of MX bonds to MM bonds (metal-metal bonds) in the filler can be about 2.0 or greater, about 3.0 or greater, or about 4.0 or greater. It should be understood that the conductive filler can be free of MM bonds. An example of a conductive filler that is typically free of MM bonds is aluminum hydroxide.

[0034] The one or more fillers in the composition preferably have an average specific gravity of about 3.5 or less, more preferably about 3.0 or less, even more preferably about 2.8 or less, even more preferably about 2.6 or less, and most preferably about 2.5 or less. The average specific gravity of the one or more fillers may be about 1.8 or greater, about 2.2 or greater, or about 2.4 or greater. Including the mass fraction m a The specific gravity v a Filler A and mass fraction m b The specific gravity v b Filler B (where m a +m b =1) is defined as:

[0035] 1 / [(m a / v a )+(m b / v b )].

[0036] Except thermally conductive filler, other fillers can comprise calcium carbonate and / or calcium oxide.If adopt, based on the gross weight of these one or more fillers, the total amount of calcium carbonate and calcium oxide is preferably about 20 weight percent or less, more preferably about 10 weight percent or less and most preferably about 5 weight percent.Based on the gross weight of these one or more fillers in composition (for example, in two-part composition), the total amount of calcium carbonate and calcium oxide can be about 0 weight percent or greater, about 0.4 weight percent or greater or about 0.8 weight percent or greater.

[0037] Preferred fillers are selected from aluminum hydroxide, aluminum oxide, aluminum powder, zinc oxide, boron nitride, and mixtures of these. Particularly preferably, the filler is selected from aluminum hydroxide, aluminum oxide, and mixtures of these. Most particularly preferred is aluminum hydroxide.

[0038] Particle size distribution

[0039] In order to achieve a combination of high thermal conductivity of the composition and the ability to mix and process the composition, the conductive filler preferably has a broad particle size distribution.

[0040] A wide particle size distribution can allow particles to pack together more efficiently. The particle size distribution can be determined by D 10 , D 50 , and D 90 Characterize, which corresponds to the 10th percentile, 50th percentile (median), and 90th percentile of particle size. Particle size is based on ISO 13320, using 2.24×10 -3 M tetrasodium pyrophosphate decahydrate solution (1 g Na4P2O7×10H2O in 1000 ml deionized water) was measured as the dispersion medium.

[0041] Fillers with a broad particle size distribution may be characterized by one or more of the following: generally high D 90 / D 50 Ratio, usually high D 90 / D 10 ratio, or usually high D 50 / D 10 ratio, or any combination thereof. Preferably, D 90 / D 50 The ratio of is about 3 or greater, about 4 or greater, about 5 or greater, about 6 or greater, or about 8 or greater. 90 / D 50 The ratio of D may be about 100 or less, or about 40 or less. Preferably, D 90 / D 10 The ratio of D to D is about 20 or greater, about 40 or greater, about 60 or greater, or about 80 or greater. 90 / D 10The ratio of may be about 1000 or less, or about 400 or less. 90 / D 50 The ratio of D may be about 100 or less, or about 40 or less. Preferably, D 50 / D 10 The ratio of is about 8 or greater, about 10 or greater, or about 12 or greater. 50 / D 10 The ratio of may be about 100 or less, or about 40 or less. The large particles in the conductive filler (such as those formed by D 90 The value of D should be high enough to create sites for filling one or more smaller particles. 90 is about 10 μm or more, more preferably about 20 μm or more, even more preferably about 40 μm or more, and most preferably about 60 μm or more. If D 90 If D is too large, it may be difficult to process the composition. 90 The conductive filler particles (such as those formed by D 10 The D values ​​should be small enough so that they can fit into the sites between the large particles. 10 is about 4 μm or less, about 2 μm or less, or about 1 μm or less. Typically, it is difficult and expensive to make very small particles. Thus, although smaller particles can be used, it is preferred that D 10 The conductive filler may have a first portion having an average particle size of about 10 μm or less and a second portion having an average particle size of about 50 μm or more (preferably, the first portion and the second portion are each present in an amount of about 25 weight percent or more, about 30 weight percent or more, or about 35 weight percent or more of the conductive filler).

[0042] Figure 1 The effect of having a wide particle size distribution 6 (B) on the ability to pack small particles 7 between larger particles 8 is shown compared to a filler (A) having a narrow particle size distribution 4. As the concentration of particles using a wide particle size distribution increases, the particles 2 are closer together and the matrix phase material 3 can bridge between two particles. Adhesion and / or bridging of the matrix phase to the particle surface may reduce the ability of the composition to flow or process. To improve processability, the particles preferably have a surface modifier. For example (C) has a wide particle size distribution 6 and a coating 5 (e.g., of a surfactant) to reduce or minimize bonding between the matrix phase material and the filler.

[0043] Figure 2is an optical micrograph of an example of a conductive filler aluminum hydroxide (ie, Al(OH)3) having a broad particle size distribution.

[0044] Filler surface modifier

[0045] Although in many filled polymer systems, it is desirable to have good compatibility and / or combination between the matrix phase and the filler phase, the applicant has determined that for these highly filled compositions, such compatibility and / or combination can produce bridging between adjacent filler particles to prevent the composition from flowing. Preferably, the matrix phase material is not combined with the surface of the filler. For example, covalent bonding, ionic bonding and hydrogen bonding can be reduced, minimized or even avoided completely. This can be achieved by selecting a matrix phase material and a conductive filler material. Alternatively, the filler material can be treated with one or more surface modifiers to reduce, minimize or eliminate the combination with the matrix phase material.

[0046] The surface modifier may partially or completely cover the surface of the conductive filler particles. The surface modifier may have one or more functional groups that react with the conductive filler particles. In this way, the surface modifier may be covalently bonded to the conductive filler. For example, the conductive filler may include M-OH groups, where M is a metal atom, and the surface modifier may include a functional group that reacts with the M-OH groups to form a direct or indirect bond between the surface modifier and M.

[0047] The surface of the conductive filler can be hydrophobized with a surface modifier. For example, the surface modifier can include an alkyl component and one or more functional groups at or near one end of the alkyl component. The alkyl component preferably includes about 6 or more carbon atoms, more preferably about 8 or more carbon atoms, even more preferably about 10 or more carbon atoms, and most preferably about 12 or more carbon atoms. The one or more functional groups can be selected to react with the surface of the conductive filler. For example, the one or more functional groups can include one or more alkoxysilanes. Such functional groups can be particularly useful for binding the surface modifier to a conductive filler including an M-OH group, such as aluminum hydroxide. An example of the reaction between a conductive filler and a surface modifier is shown in Figure 3 middle.

[0048] It should be understood that the surface modifier can be added to the filler before or after the conductive filler is mixed with the matrix phase material. For example, the conductive filler can be coated with and / or reacted with the surface modifier before the conductive filler is mixed with the matrix phase material. As another example, the surface modifier can be mixed with the matrix phase material to form a premix, which is then combined with the conductive filler. As another example, the conductive filler can be mixed with the matrix phase material, and then the surface modifier can be added to the mixture.

[0049] Matrix phase

[0050] The matrix phase of the thermal interface material typically includes, consists essentially of, or consists entirely of: one or more liquid materials. For example, the matrix phase of the first part, the second part, or both may include one or more materials that are liquid at room temperature. Based on the total weight of the matrix phase of the part, the amount of liquid compounds in the first part, the second part, or both is preferably about 50 weight percent or greater, more preferably about 70 weight percent or greater, even more preferably about 85 weight percent or greater, even more preferably about 95 weight percent or greater, and most preferably about 98 weight percent or greater. Based on the total weight of the matrix phase of the part, the amount of liquid compounds in the first part, the second part, or both can be about 100 weight percent or less. Since the matrix phase is preferably a secondary phase (i.e., present in an amount of about 50 volume percent or less of the composition), the amount of liquid compounds in the first part, the second part, or both is preferably about 50 volume percent or less based on the total weight of the part. The one or more liquids should be present in sufficient amounts so that each part can be mixed without breaking. Preferably, the weight percent of the one or more liquid compounds in the first part, the second part, or both is about 3 weight percent or greater, about 5 weight percent or greater, or about 7 weight percent or greater, based on the total weight of the parts. The one or more liquids should be present in sufficiently low amounts so that separation between filler particles is reduced, and the thermal conductivity of the part or the entire composition measured on a thermal interface material tester from ZFW, Stuttgart, according to ASTM 5470-12 is about 2.0 W / mK or greater, about 2.5 W / mK or greater, about 2.8 W / mK or greater, about 2.9 W / mK or greater, or about 3.0 W / mK or greater, wherein the test is performed in Spaltplus mode at a thickness of 1.8-1.2 mm; the described thermal interface material is considered to be Type I (viscous liquid) as described in ASTM 5470-12, heating the upper contact to about 40°C and the lower contact to about 10°C, resulting in a sample temperature of about 25°C. Preferably, the one or more liquid compounds in the first part, the second part, or both are about 30 weight percent or less, more preferably about 25 weight percent or less, even more preferably about 20 weight percent or more, even more preferably about 15 weight percent or less, and most preferably about 13 weight percent or less, based on the total weight of the parts.

[0051] The total amount of matrix phase in the thermal interface material (e.g., after mixing the first and second parts, and optionally after reacting the two parts) is preferably about 30 weight percent or less, more preferably about 25 weight percent or less, even more preferably about 20 weight percent or less, even more preferably about 15 weight percent or less, and most preferably about 13 weight percent or less, based on the total weight of the composition. The total amount of matrix phase in the thermal interface material (e.g., after mixing the first and second parts, and optionally after reacting the two parts) is preferably about 3 weight percent or greater, more preferably about 5 weight percent or greater, even more preferably about 7 weight percent or greater, and most preferably about 8 weight percent or greater, based on the total weight of the composition.

[0052] The first portion (i.e., the carbamate-containing portion) includes one or more carbamate-containing compounds. The carbamate-containing compound can be any compound that includes a carbamate group, and preferably includes two or more spaced-apart carbamate groups. The spaced-apart carbamate groups are typically separated by 6 or more, 10 or more, or 15 or more atoms on the backbone of the compound. The carbamate-containing compound can be a monomer, an oligomeric compound. The oligomeric compound can be a prepolymer. The carbamate-containing compound can be prepared by reacting an isocyanate-containing compound with a phenol-containing compound to form a carbamate group. The carbamate-containing compound

[0053] It should be understood that a carbamate-containing compound comprising two or more carbamate groups can be formed by i) reacting an isocyanate group in an isocyanate-containing compound with a phenol-containing compound having a single phenol group, wherein the isocyanate-containing compound comprises two or more spaced-apart isocyanate groups; or ii) reacting each phenol group in a phenol-containing compound with an isocyanate-containing compound having a single isocyanate group, wherein the phenol-containing compound comprises two or more spaced-apart phenol groups. Typically, the spaced-apart isocyanate groups or spaced-apart phenol groups are separated by 6 or more, 10 or more, or 15 or more atoms on the backbone of the compound.

[0054] The first part and / or the entire two-part composition are preferably substantially free of isocyanate-containing compounds, so that the part and the composition have good shelf life stability. Without being bound by theory, it is believed that the high concentration of filler and / or the amount of water in the filler can cause the polymerization and / or crosslinking of isocyanate-containing compounds, causing the viscosity of the first part to increase or even solidify. Preferably, based on the gross weight of the first part or based on the gross weight of the matrix phase of the first part, the amount of isocyanate groups in the first part is preferably about 0.10 weight percent or less, more preferably about 0.05 weight percent or less, even more preferably about 0.01 weight percent or less and most preferably about 0.005 weight percent or less. The first part can even be completely free of isocyanate groups. The molar ratio of isocyanate groups to carbamate groups in the first part is preferably about 0.35 or less, more preferably about 0.20 or less, even more preferably about 0.10 or less, even more preferably about 0.03 or less and most preferably about 0.01 or less. The molar ratio of isocyanate groups to urethane groups in the first part may be about 0.00 or greater.

[0055] The carbamate-containing compound preferably has an equivalent weight (i.e., molecular weight divided by the number of carbamate groups) of about 10,000 g / equivalent or less, more preferably about 7,000 or less, even more preferably about 4,000 or less, even more preferably about 3,000 or less, and most preferably about 2,000 or less. The carbamate-containing compound may have an equivalent weight of about 300 g / equivalent or greater, about 500 g / equivalent or greater, or about 700 g / equivalent or greater. The carbamate-containing compound preferably has a number average molecular weight of about 20,000 g / mole or less, more preferably about 10,000 or less, even more preferably about 7,000 or less, even more preferably about 6,000 or less, and most preferably about 5,000 or less. The carbamate-containing compound preferably has a number average molecular weight of 500 g / mol or greater, about 1000 g / mol or greater, or about 1,500 g / mol or greater. The molecular weight can be measured by gel permeation chromatography (GPC), for example, with a Malvern Viscothek GPC max device. Tetrahydrofuran (THF) is preferably used as an eluent, and a PL GELMIXED D (Ailent, 300*7.5 mm, 5 μm) can be used as a column with a refractive index and / or light scattering detector. For example, a MALVERN Viscotek TDA can be used as a detector.

[0056] The carbamate-containing compound can be prepared by reacting an isocyanate-containing compound including one or more isocyanate groups with a phenol-containing compound including one or more phenol groups, wherein the resulting compound includes two or more carbamate groups. The isocyanate-containing compound can be a prepolymer. The isocyanate-containing prepolymer can be formed by reacting a diisocyanate compound with a polyol, wherein an excess of isocyanate is used to react substantially all of the polyols. The diisocyanate can include aromatic isocyanates, aliphatic isocyanates, or both. Preferably, the diisocyanate includes aromatic diisocyanates or is substantially composed of aromatic diisocyanates. It should be understood that the diisocyanate can be replaced by a compound including more than two isocyanate groups. The polyol is preferably a polyether polyol. The polyol can have two or more OH groups. It should be understood that instead of using a prepolymer, the phenol-containing compound can react directly with the diisocyanate.

[0057] Phenol-containing compounds typically have a straight chain hydrocarbon attached to the phenol group to provide some aliphatic characteristics to the compound. The straight chain hydrocarbon preferably includes about 3 or more carbon atoms, more preferably about 5 or more carbon atoms, even more preferably about 8 or more carbon atoms, and most preferably about 10 or more carbon atoms. The straight chain hydrocarbon preferably includes about 50 or less carbon atoms, about 30 or less carbon atoms, about 24 or less carbon atoms, or about 18 or less carbon atoms. The phenol-containing compound is preferably a lipid.

[0058] Examples of carbamate-containing compounds are the reaction products of aromatic polyisocyanate prepolymers (based on toluene diisocyanate reacted with a polyether polyol, having an NCO content of about 4%-5% and an equivalent weight of about 500-1500 g / equivalent) with phenolic lipids (such as cardanol). The compounds are preferably reacted in the presence of a catalyst, heat, and an inert atmosphere. The reaction temperature is preferably about 30° C. or higher, more preferably about 40° C. or higher. The reaction temperature is preferably about 130° C. or lower, more preferably about 100° C. or lower. The catalyst may be a Lewis acid or Lewis base catalyst. Particularly preferred catalysts are tin catalysts, particularly preferably dioctyltin dineodecanoate, or amine catalysts, particularly tertiary amine catalysts, such as DABCO (1,4-diazabicyclo[2.2.2]octane).

[0059] The compound containing carbamate can be a blocked isocyanate compound, wherein the isocyanate group is blocked by a phenol group to form a carbamate group. Although this type of blocked isocyanate group (that is, the isocyanate group converted into a carbamate group) can be deblocked by heating, it is desirable to avoid heating the two-part composition after mixing in each part and contacting with a device (for example, a heat generating device). In this way, it is desirable to react the carbamate group with the compound of the second portion without deblocking the compound (that is, not forming an isocyanate group). Therefore, the second portion preferably includes one or more carbamate-reactive compounds, which can react with the carbamate group for at least polymerizing or crosslinking the compound containing carbamate. The carbamate-reactive compound can react with the carbamate group to increase the viscosity of the composition.

[0060] The carbamate reactive compound can include any carbamate reactive group that can react with the carbamate group. Preferably, the carbamate reactive compound includes one or more amine groups. The amine group can be any amine group (primary, secondary, or tertiary), and the preferred amine group is a primary amine and a secondary amine, and the most preferred amine group is a primary amine. The carbamate reactive compound is preferably a polyamine including two or more amine groups. For example, the carbamate reactive compound can include a first polyamine with two amine groups and a second polyamine with more than two amine groups. The amine groups of the polyamines are typically spaced apart by two or more backbone atoms (i.e., the atoms that limit the shortest covalent connection between the two groups). Preferably, each amine group is spaced apart by 5 or more backbone atoms, more preferably about 6 or more backbone atoms, even more preferably about 8 or more backbone atoms, and most preferably about 10 or more backbone atoms and one or more other amine groups.

[0061] The urethane reactive component (e.g., the second part) may include one or more polyols. However, any reaction between the polyol and the first component may be minimal, particularly for applications where heating the composition (e.g., after mixing) to a temperature of about 60° C. or higher (or about 100° C. or higher) is avoided. If a polyol is present in the second part, the molar ratio of hydroxyl groups (e.g., of the polyol) to amine groups (e.g., of the polyamine) is preferably about 1.5 or less, more preferably about 0.9 or less, even more preferably about 0.6 or less, and most preferably about 0.3 or less. The molar ratio of hydroxyl groups to amine groups in the second part may be about 0.0 or greater, or about 0.01 or greater.

[0062] Surface modifier (for fillers)

[0063] In many filled polymer systems, it is desirable to have good compatibility and / or combination between the matrix phase and the filler phase, but it has been unexpectedly determined that for these highly filled compositions, such compatibility and / or combination can produce bridges between adjacent filler particles to prevent the composition from flowing. Preferably, the matrix phase material is not combined with the surface of the filler. For example, covalent bonding, ionic bonding and hydrogen bonding can be reduced, minimized or even avoided completely. This can be achieved by selecting a matrix phase material and a conductive filler material. Alternatively, the filler material can be treated with one or more surface modifiers to reduce, minimize or eliminate the combination with the matrix phase material.

[0064] The surface modifier may partially or completely cover the surface of the conductive filler particles. The surface modifier may have one or more functional groups that react with the conductive filler particles. In this way, the surface modifier may be covalently bonded to the conductive filler. For example, the conductive filler may include an M-OH group, where M is a metal atom, and the surface modifier may include a functional group that reacts with the M-OH group to form a direct or indirect bond between the surface modifier and M.

[0065] The surface of the conductive filler can be hydrophobized with a surface modifier. For example, the surface modifier can include an alkyl component and one or more functional groups at or near one end of the alkyl component. The alkyl component preferably includes about 6 or more carbon atoms, more preferably about 8 or more carbon atoms, even more preferably about 10 or more carbon atoms, and most preferably about 12 or more carbon atoms. The one or more functional groups can be selected to react with the surface of the conductive filler. For example, the one or more functional groups can include one or more alkoxysilanes. Such functional groups can be particularly useful for binding the surface modifier to a conductive filler including an M-OH group, such as aluminum hydroxide. An example of the reaction between a conductive filler and a surface modifier is shown in Figure 3 middle.

[0066] It should be understood that the surface modifier can be added to the filler before or after the conductive filler is mixed with the matrix phase material. For example, the conductive filler can be coated with and / or reacted with the surface modifier before the conductive filler is mixed with the matrix phase material. As another example, the surface modifier can be mixed with the matrix phase material to form a premix, which is then combined with the conductive filler. As another example, the conductive filler can be mixed with the matrix phase material, and then the surface modifier can be added to the mixture.

[0067] like Figure 4 As shown in (A), when a conductive filler having a narrow particle size distribution is employed, the resulting composition can have a rough surface even when the filler loading is low (e.g., only about 60 weight percent). Figure 4As shown in (B), the ability to increase filler loading is enhanced by using fillers with a broad particle size distribution. Figure 4 As demonstrated in (C), the ability to increase filler loading is further enhanced by using fillers with a broad particle size distribution and also adding surface modifiers that reduce, minimize or eliminate bonding between the matrix phase material and the filler particles.

[0068] catalyst

[0069] The composition preferably includes one or more catalysts for accelerating the reaction between the carbamate-containing compound and the carbamate-reactive compound (such as a compound containing polyamines). The catalyst may include a Lewis acid or a Lewis base catalyst. The Lewis acid catalyst may be an organometallic compound, which preferably includes one or more aliphatic groups. Each aliphatic group preferably includes four or more, six or more, or eight or more carbon atoms. The organometallic compound is preferably a tin compound. An example of a tin-containing Lewis acid catalyst is dioctyltin dineodecanoate. The one or more catalysts may include an amine catalyst. The amine catalyst preferably includes an aliphatic group, an aromatic group, or both. An example of an amine catalyst is tri-2,4,6-dimethylaminomethylphenol or DABCO (1,4-diazabicyclo[2.2.2]octane). The catalyst should be used in an amount sufficient to accelerate the reaction between the carbamate-containing compound and the polyamines. Preferably, based on the total weight of the matrix phase in the total composition (or based on the total weight of the liquid materials in the composition), the amount of the catalyst is about 0.05 weight percent or more, more preferably about 0.10 weight percent or more, even more preferably about 0.20 weight percent or more, even more preferably about 0.4 weight percent or more, and most preferably about 0.75 weight percent or more. Preferably, based on the total weight of the matrix phase in the total composition (or based on the total weight of the liquid materials in the composition), the amount of the catalyst is about 10 weight percent or less, more preferably about 8 weight percent or less, even more preferably about 5 weight percent or less, and most preferably about 4 weight percent or less.

[0070] The catalyst can be provided in the first part, the second part, or both. As an example, the first part and the second part can each contain both an amine catalyst and an organometallic catalyst (e.g., a tin-containing Lewis acid catalyst). As another example, one part (e.g., the first part or the second part) can include an organometallic catalyst (e.g., a tin-containing Lewis acid catalyst) and the other part can include an amine catalyst. As another example, the first part and the second part can both include an organometallic catalyst (e.g., a tin-containing Lewis acid catalyst) that can be the same or different.

[0071] Preferred catalysts are liquid at room temperature.

[0072] Plasticizers

[0073] The first part, the second part, or the two parts can include one or more plasticizers.Plasticizer is preferably a compound that does not react with the carbamate group of the first part.Plasticizer is preferably a compound that does not react with the amine group of the second part.Plasticizer is at room temperature a liquid and forms a part of the matrix phase.Based on the gross weight of the matrix phase of part, plasticizer can be present in the first part, the second part, or both with about 0 weight percent or larger, preferably about 10 weight percent or larger, more preferably about 20 weight percent or larger and most preferably about 25 weight percent or larger amount.Based on the gross weight of the matrix phase of part, plasticizer can be present in the first part, the second part, or both with about 75 weight percent or smaller, preferably about 65 weight percent or smaller, more preferably about 60 weight percent or smaller and most preferably about 55 weight percent or smaller amount.

[0074] Preferred plasticizers have a weight average molecular weight of about 2,000 g / mole or less, more preferably about 1,000 g / mole or less, even more preferably about 800 g / mole or less, and most preferably about 600 g / mole or less. The plasticizer is liquid at a temperature of about 100° C. Preferred plasticizers have a molecular weight of about 125 g / mole, more preferably about 175 g / mole, and most preferably about 225 g / mole.

[0075] Colorants

[0076] Composition can optionally include dye, pigment or other coloring agents, for providing predetermined color to composition.If adopt, coloring agent can be included in first part, second part or both.Based on the gross weight of two-part composition, coloring agent typically exists with about 1 weight percent or less, about 0.5 weight percent or less or about 0.2 weight percent or less amount.Coloring agent can be provided as pure material or can be mixed with carrier material (typically carrier liquid).Carrier material is preferably the material described herein for first part and / or second part.According to the teaching content of this paper, for example, carrier material can be epoxy resin, compound containing carbamate, plasticizer, polyol, catalyst, carbamate reactive compound or surface modifier.

[0077] The matrix phase of the first part (e.g., as defined by the liquid compound and / or the composition including the filler) preferably includes a significant amount of a carbamate-containing compound. Preferably, the amount of the carbamate-containing compound in the first part is about 10 weight percent or greater, more preferably about 15 weight percent or greater, and most preferably about 18 weight percent or greater, based on the total weight of the liquid compound in the first part. The amount of the carbamate-containing compound in the first part can be about 90 weight percent or less, about 80 weight percent or less, about 70 weight percent or less, about 60 weight percent or less, or about 50 weight percent or less, based on the total weight of the liquid compound in the first part.

[0078] The matrix phase of the second part (e.g., as defined by the liquid compound and / or the composition including the filler) preferably includes a significant amount of a carbamate-reactive compound (e.g., a polyamine). Preferably, the amount of the carbamate-reactive compound in the second part is about 10 weight percent or greater, more preferably about 15 weight percent or greater, even more preferably about 20 weight percent or greater, and most preferably about 25 weight percent or greater, based on the total weight of the liquid compound in the second part. The amount of the carbamate-reactive compound (e.g., a polyamine) in the second part can be about 90 weight percent or less, about 80 weight percent or less, about 70 weight percent or less, about 60 weight percent or less, or about 50 weight percent or less, based on the total weight of the liquid compound in the second part.

[0079] Based on the total weight of the composition, the total amount of the carbamate-containing compound, the one or more catalysts, the carbamate-reactive compound, the surface modifier, the one or more fillers, and the plasticizer is preferably about 95 weight percent or greater, more preferably about 97 weight percent or greater, even more preferably about 98 weight percent or greater, even more preferably about 99 weight percent or greater, and most preferably about 99.5 weight percent or greater. Based on the total weight of the composition, the total amount of the carbamate-containing compound, the one or more catalysts, the polyamine compound, the alkoxysilane surface modifier, ATH, optional calcium carbonate and calcium oxide, and the plasticizer is preferably about 95 weight percent or greater, more preferably about 97 weight percent or greater, even more preferably about 98 weight percent or greater, even more preferably about 99 weight percent or greater, and most preferably about 99.5 weight percent or greater.

[0080] The molar ratio of the carbamate groups in the first part to the amine groups in the second part is preferably about 0.1 or more, about 0.2 or more, about 0.3 or more, about 0.4 or more, about 0.5 or more, or about 0.6 or more. The molar ratio of the carbamate groups in the first part to the amine groups in the second part is preferably about 10 or less, about 5.0 or less, about 3.5 or less, about 2.5 or less, about 2.0 or less, or about 1.7 or less.

[0081] Gap filling properties

[0082] The two-part composition should be able to fill the gap between the parts and provide a thermally conductive path between the two parts. Typically, after mixing, the two-part composition (i.e., thermal interface material) is placed on one of the parts, and then the other part is pressed into the mixture. Each of the two parts of the thermal interface material preferably has a sufficiently low viscosity so that the material can be mixed with the other part and the parts can be easily pressed into the mixture. After mixing, the two-part composition should have a sufficiently high viscosity so that the mixture does not flow away from its application area (e.g., before the second part is pressed into the mixture). The viscosity of one of the parts or the mixture can be characterized by a press-in force as described herein. Preferably, the first part, the second part, the mixture, or any combination thereof is characterized by a press-in force of about 1000N or less, about 900N or less, about 800N or less, about 700N or less, about 600N or less, about 500N or less, or about 400N or less (initial, measured at 23°C). Preferably, the first part, the second part, the mixture, or any combination thereof is characterized by an indentation force of about 5N or greater, about 10N or greater, about 30N or greater, about 60N or greater, about 80N or greater, about 90N or greater, or about 100N or greater (initial, measured at 23°C).

[0083] Storage stability

[0084] Materials according to the teachings herein may need to be storage stable at room temperature and / or at shipping temperatures. The storage stability of the material can be characterized by an accelerated test in which the material is exposed to a temperature of about 55°C for 3 days. Preferably, each part of the two-part composition maintains its good viscosity even after aging for about 3 days at a temperature of about 55°C before mixing. In particular, the first part, the second part, or both should be selected so that there is little or no increase in viscosity after aging for 3 days at 55°C. Preferably, each part is characterized in that the ratio of the indentation force after aging (e.g., 3 days at 55°C) to the initial indentation force is about 4.0 or less, about 3.0 or less, about 2.0 or less, about 1.5 or less, or about 1.3 or less. Typically, the ratio of the indentation force after aging to the initial indentation force is about 0.5 or greater, 0.75 or greater, or about 1.0 or greater; however, a value of 0.5 or less is also possible. After aging (e.g., 3 days at 55°C), the penetration force of the first part, the second part, or both is preferably about 1000N or less, about 900N or less, about 800N or less, about 700N or less, about 600N or less, about 500N or less, or about 400N or less.

[0085] application

[0086] Thermal interface materials according to the teachings herein may be used in any device or system requiring a polymer or oligomer material with good thermal conductivity. Figure 5 1 is a diagram illustrating features of a device 10 including a thermal interface material 12. The device may require a heat flow 20 from a first component 14 of the device to a second component 16 of the device 10. Figure 5 As shown in , heat flow can be through the thermal interface material 12. The second component 16 of the device can have a surface 20 (internal or external) that allows heat to be removed from the second component.

[0087] The thermal interface material can be used as a gap filling material. The thermal interface material can be used as a sealing material. In some applications, it may be necessary to apply a thin layer (e.g., about 2 mm or less, about 1 mm or less, about 0.5 mm or less, or about 0.3 mm or less) of the thermal interface material. As such, the thermal interface material preferably has a low viscosity and / or has good mixing behavior (e.g., has a smooth appearance that does not break after mixing) so that thin areas or layers can be prepared.

[0088] An article comprising one or more battery cells, a battery cover having a surface for contacting a cooling unit or a circulating cooling fluid, preferably having a thermal interface material inserted between the battery cell and the battery cover. The thermal interface material provides a path for conducting thermal energy from the battery cell to the battery cover for managing the temperature of the battery cell. The battery cells may be provided as one or more modules. In the absence of a thermal interface material, there may be a gap (at least in some areas) between the battery module and the conductive plate (e.g., of the housing). Figure 6 is a diagram showing features that may be used for thermal management of one or more battery modules. The battery / thermal management system 30 includes a thermal interface material 32 for filling a gap between one or more battery modules 34 and a metal surface 36. The thermal interface material may be applied by being placed on the surface of the battery module or by being placed on a metal surface. The metal surface may be a cooling plate or other component arranged to draw heat out of the system.

[0089] Test Method

[0090] Particle size distribution.

[0091] Unless otherwise stated, the particle size distribution of the fillers was measured by laser diffraction in acetone.

[0092] Thermal conductivity

[0093] The thermal conductivity was measured according to ASTM 5470-12 on a thermal interface material tester from ZFW, Stuttgart. The test was carried out in Spaltplus mode with a thickness of 1.8-1.2 mm. The thermal interface material described is considered to be type I (viscous liquid) as described in ASTM 5470-12. The upper contact was heated to about 40° C. and the lower contact was heated to about 10° C., resulting in a sample temperature of about 25° C. When applied from a manual cartridge system, the A and B components were mixed with a static mixer. This is the method used in the examples of the present application.

[0094] Pressing force

[0095] The indentation force is measured with a tensiometer (Zwick). A composition (e.g., a gap filler material) is placed on a metal surface. An aluminum piston with a diameter of about 40 mm is placed on top and the material is compressed to an initial position of 5 mm. The material is then compressed from 5 mm to 0.3 mm at a speed of about 1 mm / s, and the force deflection curve is recorded. The force (N) at 0.5 mm thickness is then reported in the data table and is considered the indentation force. Materials with low viscosity have an indentation force of 700 N or less. High viscosity materials have an indentation force greater than 700 N, or about 800 N or more. Materials with low viscosity preferably have an indentation force of about 600 N or less, even more preferably about 500 N or less, and most preferably about 400 N or less.

[0096] Mixing Capacity

[0097] The ability to mix a composition is determined by the ability to produce a single mass of material with a smooth surface. Such materials have "good" mixing. Poor mixing occurs when the surface is rough and / or the material breaks up when removed from the mixer.

[0098] Material

[0099]

[0100]

[0101] Examples

[0102] Urethane prepolymer-1Use the composition shown in Table 2 to prepare urethane prepolymer-1. Cardanol and polyisocyanate prepolymer-1 are added to the reactor and heated to about 60°C under continuous mixing. Then dibutyltin dilaurate catalyst is added, and the reaction is carried out for about 45 minutes at a temperature of about 80°C under nitrogen. After 45 minutes, vacuum is applied for 10 minutes and the reactor is cooled to room temperature. The reaction product (urethane prepolymer-1) has the following characteristics shown in Table 2. The molecular weight data of the polyurethane prepolymer are measured by gel permeation chromatography (GPC) with Malvern Viscotek GPC max equipment. EMSURE-THF (ACS, Reag.Ph EUR is used for analysis) is used as eluent, PL GELMIXED D (Ailent, 300*7.5mm, 5μm) is used as column, and MALVERN Viscotek TDA is used as detector.

[0103]

[0104] Examples A-1, A-2, A-3, and A-4 are part A compositions including isocyanate prepolymers. These compositions are prepared by first mixing the liquid components and then adding fillers in the amounts shown in Table 3. A planetary mixer is used to mix all the part A compositions and to mix all the part B composition materials. As shown in Table 3, Examples A-1, A-2, A-3, and A-4 all have high initial press-in forces and also become solid after 3 days at 55°C.

[0105] The thermal conductivity was measured according to ASTM 5470-12 on a thermal interface material tester from ZFW, Stuttgart, wherein the test was carried out in Spaltplus mode at a thickness of 1.8-1.2 mm; the thermal interface material described was considered to be type I (viscous liquid) as described in ASTM 5470-12, the upper contact was heated to about 40°C and the lower contact to about 10°C, resulting in a sample temperature of about 25°C.

[0106]

[0107] In Examples A-4, A-5, A-6, A-7, and A-8, the addition of additional silane compounds and / or additional dimethyl malonate appears to reduce the initial indentation force. However, all of these materials have poor storage stability, as shown by the compositions being cured at 55° C. for 3 days, such that the compositions could no longer be tested for indentation force, as shown in Table 4.

[0108]

[0109] Example B-1 is a Part B composition including a polyol component and having the composition shown in Table 5.

[0110]

[0111] Examples A-9, A-10, A-11, A-12, A-13, A-14, A-15, A-16, A-17, A-18, A-19, and A-20 are part A compositions prepared using urethane-prepolymer-1, and the compositions and properties of these compositions are shown in Tables 7, 8, and 9. It can be seen here that part A compositions having low initial viscosity, good thermal stability, and high thermal conductivity can be prepared.

[0112]

[0113]

[0114]

[0115]

[0116] Examples 1 and 2 are 2-part compositions based on a first part comprising an isocyanate and a second part comprising a polyol capable of reacting with the isocyanate. These compositions are shown in Table 11.

[0117]

[0118] Examples 3-14 are thermal interface materials based on a urethane-containing A component and a polyamine-containing B component. As shown in Tables 12 and 13, when the urethane-containing A component and the polyamine-containing B component are mixed, the composition has a generally low initial press-in force, which allows gap filling. This is even possible when the thermal conductivity is about 3 W / mK. For example, when the composition includes greater than 85 weight percent aluminum hydroxide and / or a total concentration of 89 weight percent or more filler.

[0119]

[0120]

[0121] Table 14 shows the importance of having a catalyst in the A-component and / or the B-component in affecting the increase in viscosity (as characterized by the indentation force) at room temperature.

[0122]

Claims

1. A two-part composition for a thermal interface material, the two-part composition include: i) The first part, which contains at least a) a prepolymer comprising two or more urethane groups; ii) the second part, which contains at least: b) one or more polyamine compounds capable of reacting with the prepolymer; Wherein the composition comprises: c) one or more catalysts for catalyzing the reaction between the prepolymer and the polyamine compound; and d) 50 weight percent or greater of one or more thermally conductive fillers based on the total weight of the two-part composition; and The prepolymer is formed by capping one or more isocyanate groups of an aromatic polyisocyanate prepolymer with a phenolic group of a capping compound.

2. A two-part composition as claimed in claim 1, in, The aromatic polyisocyanate prepolymer is formed by capping each isocyanate group of the aromatic polyisocyanate prepolymer with a phenol group of a capping compound.

3. A two-part composition as claimed in claim 1 or 2, in, The capping compound comprises a terminal phenol group attached to a straight chain hydrocarbon comprising 6 or more carbon atoms; and the straight chain hydrocarbon comprises 60 or fewer carbon atoms.

4. A two-part composition as claimed in claim 3, in, The terminal phenolic group is a single terminal phenolic group.

5. A two-part composition as claimed in claim 1 or 2, in, The one or more polyamine compounds, the prepolymer, or both have an average functionality greater than 2.

6. A two-part composition as claimed in claim 1 or 2, in, The one or more thermally conductive fillers include fillers selected from aluminum hydroxide, aluminum oxide, aluminum powder, zinc oxide, boron nitride, and / or mixtures of any of these.

7. A two-part composition as claimed in claim 1 or 2, in, The one or more thermally conductive fillers include fillers selected from aluminum hydroxide, aluminum oxide, and / or mixtures of any of these.

8. A two-part composition as claimed in claim 1 or 2, in, The one or more thermally conductive fillers is aluminum hydroxide.

9. A two-part composition as claimed in claim 1 or 2, in, The one or more thermally conductive fillers include aluminum hydroxide.

10. A two-part composition as claimed in claim 8, in, The first portion includes 75 weight percent or greater aluminum hydroxide, and the second portion includes 75 weight percent or greater aluminum hydroxide.

11. A two-part composition as claimed in claim 8, in, The surface of the aluminum hydroxide is partially or entirely coated with a surface modifier for reducing the hydrophilicity of the surface.

12. A two-part composition as claimed in claim 1 or 2, in, The composition comprises a D 90 / D 50 Aluminum hydroxide with a wide particle size distribution, wherein the particle size according to ISO 13320 is 2.24×10 -3 M tetrasodium pyrophosphate decahydrate solution was used as the dispersion medium for measurement, and the tetrasodium pyrophosphate decahydrate solution was 1 g Na 4 P 2 O 7 ×10H 2 O in 1000 ml of deionized water.

13. A two-part composition as claimed in claim 1 or 2, in, The composition comprises one or more plasticizers.

14. A two-part composition as claimed in claim 1 or 2, in, The composition comprises a fatty acid or an ester of a fatty acid.

15. A two-part composition as claimed in claim 1 or 2, in, The composition comprises an epoxy resin in the first part, wherein a weight ratio of the prepolymer to the epoxy resin is 0.5 or more, and / or a weight ratio of the prepolymer to the epoxy resin is 10 or less.

16. The two-part composition of claim 2, in, The composition is free of isocyanate containing compounds.

17. A two-part composition as claimed in claim 1 or 2, in, The molar ratio of the carbamate groups in the first part to the amine groups in the second part is 0.1 or more, and / or 10 or less.

18. A two-part composition as claimed in claim 1 or 2, in, The first part includes calcium carbonate in an amount of 0.1 weight percent or more based on the total weight of the first part.

19. A two-part composition as claimed in claim 1 or 2, in, The catalyst is one or more of the following: (a) a Lewis acid or a Lewis base; (b) tin catalyst; (c) an amine catalyst; (d) DABCO, wherein DABCO is 1,4-diazabicyclo[2.2.2]octane; and Wherein, the catalyst is contained in the first part, the second part or both.

20. A two-part composition as claimed in claim 19, in, The first portion comprises some or all of the catalyst.

21. A two-part composition as claimed in claim 1 or 2, in, The composition is characterized by a thermal conductivity of 2.0 W / mK or greater measured on a thermal interface material tester from ZFW, Stuttgart, according to ASTM 5470-12, wherein the test is carried out in Spaltplus mode at a thickness of 1.8-1.2 mm; the thermal interface material described is considered to be a viscous liquid of Type I as described in ASTM 5470-12, the upper contact is heated to 40° C. and the lower contact is heated to 10° C., resulting in a sample temperature of 25° C.

22. A two-part composition as claimed in claim 1 or 2, in, The two-part composition cures at room temperature and is characterized by an increase in indentation force of 100% or more after aging for 24 hours after mixing.

23. A two-part composition as claimed in claim 1 or 2, in, The first part is shelf-stable.

24. A two-part composition as claimed in claim 22, in, The indentation force of the first part after aging at 55° C. for 3 days was less than 700N.

25. A product, include: A first component that generates heat, a second component for removing heat, and a layer of thermal interface material interposed between the first component and the second component, wherein the thermal interface material provides a path for transferring heat from the first component to the second component and is formed from a two-part composition as claimed in any one of claims 1 to 24.

26. A method wherein The following steps are involved: A layer of thermal interface material is disposed between a first component and a second component and pressure is applied so that the thermal interface material contacts both the first component and the second component and fills a gap between the two components, wherein the thermal interface material is formed from a two-part composition as claimed in any one of claims 1 to 24.

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