Curable thermally conductive adhesive and thermally conductive member

Abstract

A curable thermally conductive adhesive containing a curable binder and a thermally conductive filler, the curable thermally conductive adhesive being characterized in that a cured product of the curable thermally conductive adhesive has a mass reduction rate of 1.5% or less after repeated 20 times of-40 DEG C for 3 hours and 80 DEG C for 3 hours of thermal cycling tests, and an elastic modulus at 80 DEG C of 1.2 * 10 < 8 > Pa or less.

Description

Technical Field

[0001] The present invention relates to a curable thermally conductive adhesive and a thermally conductive member used in electronic devices such as battery packs. Background Art

[0002] Thermally conductive compositions are used, for example, to fill a space between a heating element and a heat sink, thereby conducting heat generated in the heating element and dissipating it from the heat sink. Thermally conductive compositions are generally curable and are often cured after filling to be used as a cured product. Thermally conductive compositions play an important role in a variety of electronic devices, including battery components such as lithium-ion battery (LiB) components for electric vehicles (EVs), power electronics, electronic packaging, LEDs, solar cells, and power grids.

[0003] Thermally conductive compositions are used in LiB modules for electric vehicles, for example. As EV production continues to increase, reducing their viscosity before curing is crucial to improve EV productivity. This reduction in viscosity shortens the application time using a dispenser and the time required to assemble the applied thermally conductive composition, such as the module housing.

[0004] Furthermore, thermally conductive compositions are required to have even higher thermal conductivity, leading to attempts to fill them with thermally conductive fillers at high densities. Furthermore, in LiB assemblies for EVs, for example, improved adhesion to various components is sometimes required to ensure adhesion to battery cells, module housings, cooling plates, and the like. Furthermore, thermally conductive compositions are sometimes expected to be used in a variety of temperature environments, requiring high reliability to maintain excellent thermal conductivity and other qualities even in environments subject to repeated high and low temperatures.

[0005] For example, Patent Document 1 discloses a thermally conductive composition comprising a trifunctional or higher epoxy resin without an aromatic skeleton, a liquid bifunctional or lower epoxy resin, a curing agent, a silane compound without functional groups other than alkoxy groups, and a thermally conductive filler as a thermally conductive composition that can minimize the minimum installation gap, achieve low thermal resistance, and achieve high reliability. Reliability is evaluated, specifically, by the absence of peeling during a thermal shock test (hot and cold cycling). Epoxy resins are disclosed, for example, with an average molecular weight (Mn) in the range of 5,000 to 10,000, and various curing agents are also exemplified.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-116587 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] As mentioned above, thermally conductive compositions are sometimes required to ensure low viscosity, high thermal conductivity, and high adhesion, while also maintaining high reliability in properties such as thermal conductivity, even in environments subject to repeated high and low temperatures. However, conventional thermally conductive compositions have struggled to simultaneously meet these required properties. For example, Patent Document 1 describes a method for achieving both high thermal conductivity and high reliability. However, the use of an epoxy resin, a high-molecular-weight substance, as a curing agent results in a high viscosity of the thermally conductive composition, resulting in poor workability.

[0011] On the other hand, it is also conceivable to simply use a low-molecular-weight binder to reduce viscosity, or to add a plasticizer to reduce the elastic modulus along with the viscosity. However, simply using a low-molecular-weight binder or plasticizer can easily lead to volatilization in an environment with repeated exposure to high and low temperatures, causing foaming on the surface of the thermally conductive composition, making it difficult to ensure high reliability.

[0012] Therefore, an object of the present invention is to provide a curable thermally conductive adhesive having low viscosity and high reliability.

[0013] Means for solving problems

[0014] The present inventors have conducted intensive research and have discovered that, in a curable thermally conductive adhesive comprising a curable binder and a thermally conductive filler, the above-mentioned problems can be solved by reducing both the mass reduction rate after a thermal cycle test and the elastic modulus at 80°C to below a certain value. This has led to the completion of the following invention. Specifically, the present invention provides the following [1] to

[15] .

[0015] [1] A curable thermally conductive adhesive comprising a curable binder and a thermally conductive filler, wherein a cured product of the curable thermally conductive adhesive has a mass reduction rate of 1.5% or less after being subjected to a thermal cycle test of -40°C for 3 hours and 80°C for 3 hours 20 times, and an elastic modulus of 1.2×10 8 Below Pa.

[0016] [2] The curable thermally conductive adhesive according to [1], wherein the elastic modulus is 3.0×10 6 Pa or above.

[0017] [3] The curable thermally conductive adhesive according to [1] or [2] above, having a shear rate of 3.16 (1 / s) and a viscosity at 25°C of 300 Pa·s or less as measured by a rheometer.

[0018] [4] The curable thermally conductive adhesive according to any one of [1] to [3] above, wherein the binder contains an epoxy group-containing compound.

[0019] [5] The curable thermally conductive adhesive according to any one of [1] to [4] above, wherein the binder contains at least one of an amine and a thiol.

[0020] [6] The curable thermally conductive adhesive according to any one of [1] to [5] above, wherein the binder comprises an epoxy group-containing compound and an amine.

[0021] [7] The curable thermally conductive adhesive according to [6], wherein the equivalent ratio of the number of active hydrogen atoms in the amino group contained in the amine to the number of epoxy groups in the epoxy group-containing compound [(number of amino groups) / number of epoxy groups] is 1.2 or more and 2.9 or less.

[0022] [8] A curable thermally conductive adhesive according to any one of [1] to [7], comprising a first agent and a second agent, wherein the first agent contains the main agent of the adhesive and is filled in a first container, and the second agent contains a curing agent that cures by mixing with the first agent and is filled in a second container.

[0023] [9] The curable thermally conductive adhesive according to [8], wherein the difference between the viscosity (Pa·s) of the first agent and the viscosity (Pa·s) of the second agent is 150 Pa·s or less.

[0024]

[10] The curable thermally conductive adhesive according to [8] or [9], wherein the ratio of the functional group concentration (mol / g) of the second agent to the functional group concentration (mol / g) of the first agent is 1.2 or more and 2.9 or less.

[0025]

[11] A container kit filled with the curable thermally conductive adhesive described in any one of [8] to

[10] above, comprising a first container filled with the first agent and a second container filled with the second agent.

[0026]

[12] A thermally conductive component comprising a polymer matrix and a thermally conductive filler material,

[0027] The thermal conductive member has a mass reduction rate of 1.5% or less after a thermal cycle test at -40°C for 3 hours and 80°C for 3 hours, and an elastic modulus of 1.2×10 8 Below Pa.

[0028]

[13] A thermally conductive member made of a cured product of the curable thermally conductive adhesive described in any one of [1] to

[12] .

[0029]

[14] A battery pack comprising the thermally conductive member described in

[12] or

[13] above.

[0030]

[15] The curable thermally conductive adhesive described in any one of [1] to

[10] above is used as at least one of a gap material between battery cells, a gap material between a battery cell and a module housing, a gap material between a battery module and a battery pack housing, and a gap material between a battery cell and a battery pack housing.

[0031] Effects of the Invention

[0032] According to the present invention, a curable thermally conductive adhesive is provided which has low viscosity and can also have high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram showing a container kit according to one embodiment.

[0034] Figure 2 It is a schematic diagram showing a container kit according to one embodiment.

[0035] Figure 3 This is a perspective view showing a typical structure of a battery module according to the present invention.

[0036] Figure 4 This is a perspective view showing a typical configuration of a battery cell included in a battery module.

[0037] Figure 5 A perspective view showing a battery assembly with a cell-to-pack structure. DETAILED DESCRIPTION

[0038] [Curing thermally conductive adhesive]

[0039] Hereinafter, the curable thermally conductive adhesive of the present invention will be described in detail.

[0040] The curable thermally conductive adhesive of the present invention comprises a curable binder and a thermally conductive filler. In the present invention, the cured thermally conductive adhesive exhibits a mass reduction of 1.5% or less after being subjected to 20 cycles of a thermal cycle test at -40°C for 3 hours and 80°C for 3 hours, and an elastic modulus at 80°C of 1.2×10 8 Below Pa.

[0041] The curable thermally conductive adhesive having the above-described structure can ensure low viscosity, high thermal conductivity, and strong adhesion, while also achieving high reliability. Therefore, even when the cured product is subjected to thermal cycling tests, it exhibits no signs of volatilization or peeling from the adherend, maintaining excellent thermal conductivity. The curable thermally conductive adhesive of the present invention is described in detail below.

[0042] <Mass reduction rate after hot and cold cycle test>

[0043] The cured thermally conductive adhesive of the present invention (hereinafter sometimes referred to as "adhesive") has a mass reduction of 1.5% or less after being subjected to 20 cycles of a thermal cycling test at -40°C for 3 hours and 80°C for 3 hours. If the mass reduction after the thermal cycling test exceeds 1.5%, a portion of the adhesive may volatilize and foam during the thermal cycling test, resulting in volatilization marks, which are also likely to occur during actual use. If volatilization marks occur, thermal conductivity or adhesion is reduced. In addition, if the thermally conductive component is insulating, insulation is also reduced.

[0044] The mass reduction rate after the thermal cycling test is preferably 1.4% or less, more preferably 1.25% or less, and even more preferably 1.0% or less. Furthermore, the mass reduction rate after the thermal cycling test is preferably as low as possible from the perspective of reliability, but is preferably above a certain value from the perspective of maintaining a low viscosity of the adhesive before curing, and is preferably 0.05% or more, more preferably 0.1% or more, and even more preferably 0.2% or more.

[0045] In addition, from the perspective of making the adhesive before curing have a low viscosity and the perspective of balancing reliability, the mass reduction rate after the above-mentioned hot and cold cycle test is preferably 0.05% or more and 1.5% or less, more preferably 0.1% or more and 1.4% or less, and even more preferably 0.2% or more and 1.25% or less.

[0046] The mass reduction rate after the hot and cold cycle test can be obtained by performing a hot and cold cycle test on a test sample (cured product) with a thickness of 1 mm obtained by curing the adhesive, measuring the mass reduction of the test sample caused by the hot and cold cycle test, and calculating the ratio (%) of the mass reduction relative to the test sample before the hot and cold cycle test.

[0047] It should be noted that the mass reduction rate after the hot and cold cycle test can be adjusted by, for example, the type and amount of each component constituting the adhesive. For example, the mass reduction rate after the hot and cold cycle test can be reduced by using a low-volatile component as the adhesive, or using a component that does not decompose even when heated.

[0048] <Elastic modulus>

[0049] The elastic modulus of the cured product of the adhesive of the present invention at 80°C is 1.2×10 8 Pa or less. If the elastic modulus at 80°C is higher than 1.2×10 8 If the adhesive is too thin, the adhesive's flexibility will be compromised, making it difficult to adapt to changes in the distance between the adherends. Consequently, peeling is likely to occur during thermal cycling tests and in actual use. If peeling occurs, this can sometimes lead to reduced heat dissipation properties when the adhesive is used as a thermally conductive component, and a decrease in strength as a structural component. Furthermore, volatilization marks caused by foaming are likely to form, failing to improve the adhesive's reliability.

[0050] The elastic modulus of the cured product at 80°C is preferably 1.1×10 8 Pa or less, more preferably 1.0×10 8 Pa or less, more preferably 0.85×10 8 Pa or less. In addition, from the perspective of ensuring adhesive strength at high temperatures, it is preferable that the elastic modulus of the cured product at 80°C is above a certain value, for example, 3.0×10 6 Pa or more, preferably 1.0×10 7 Pa or more, more preferably 2.0×10 7 Pa or more, more preferably 3.0×10 7 Pa or above.

[0051] Furthermore, from the viewpoint of the ease with which the adhesive can follow the change in the distance between adherends and the viewpoint of improving the reliability of the adhesive, the elastic modulus of the cured product at 80°C is preferably 1.0×10 7 Pa or above and 1.2×10 8 Pa or less, more preferably 2.0×10 7 Pa or more and 1.1×10 8 Pa or less, more preferably 3.0×10 7 Pa or more and 1.0×10 8 Below Pa.

[0052] The adhesive of the present invention preferably has a cured product having an elastic modulus of 1.0×10 9 Pa or more and 5.0×10 11 Pa or less. By setting the elastic modulus of the cured product at -40°C within the above range, it is easy to increase reliability and ensure adhesive strength at low temperatures. The elastic modulus of the cured product at -40°C is more preferably 5.0×10 9 Pa or more and 1.0×10 11 Pa or less, more preferably 9.0×10 9Pa or more and 5.0×10 10 Below Pa.

[0053] The adhesive of the present invention preferably has a cured product having an elastic modulus of 1.0×10 7 Pa or more and 1.0×10 11 Pa or less. By setting the elastic modulus of the cured product at 25°C within the above range, reliability can be increased and bonding strength at room temperature can be easily ensured. In addition, the elastic modulus at high temperature can also be easily adjusted to an appropriate value. The elastic modulus of the cured product at 25°C is more preferably 8.0×10 7 Pa or more and 7.0×10 10 Pa or less, more preferably 3.0×10 8 Pa or more and 2.0×10 10 Below Pa.

[0054] The elastic modulus of the cured adhesive is the storage modulus obtained by curing the adhesive and measuring a test sample having a thickness of 1 mm using a dynamic viscoelasticity measuring apparatus under the measurement conditions described in Examples.

[0055] The elastic modulus of the cured product can be adjusted by adjusting the types and amounts of the adhesive's components. For example, the elastic modulus of the cured product can be lowered by adjusting the types and amounts of the adhesive's components to reduce the crosslinking density, or by using a highly flexible adhesive. Furthermore, the elastic modulus at 80°C can be easily lowered by increasing the amount of low-molecular-weight substances in the adhesive's curing agent.

[0056] The present invention has a mass reduction rate of less than 1.5% after the cured product passes the thermal cycle test, and an elastic modulus of 1.2×10 8 Pa or less, thereby achieving a highly reliable curable thermally conductive adhesive. More specifically, even when a low-viscosity component is used to reduce the viscosity of the adhesive, by remaining within the above parameter range, the generation of volatilization marks and peeling can be suppressed, resulting in a highly reliable curable thermally conductive adhesive.

[0057] <Glass transition temperature>

[0058] The adhesive of the present invention preferably has a cured product having a glass transition temperature of -80°C to -40°C. If the cured product has a glass transition temperature below the upper limit, the change in elastic modulus within the temperature range of a thermal cycle test (-40°C to 80°C) is minimized, facilitating enhanced reliability. Furthermore, if the cured product has a glass transition temperature above the lower limit, a wide variety of resins can be used, increasing design flexibility.

[0059] On the other hand, any cured adhesive having the above-mentioned elastic modulus may have a glass transition temperature exceeding -40°C. In this case, the glass transition temperature is preferably 15°C to 55°C, more preferably 20°C to 48°C, and even more preferably 26°C to 46°C. Changes in the elastic modulus are minimized in the temperature range above the glass transition temperature, making it easier to achieve high reliability. Furthermore, if the glass transition temperature is above the lower limit, it is easier to ensure adhesive strength at high temperatures.

[0060] It should be noted that the glass transition temperature of the cured adhesive can be measured using a dynamic viscoelasticity measuring apparatus described in the Examples on a 1 mm thick test sample (cured product) obtained by curing the adhesive. Furthermore, the glass transition temperature can be adjusted by adjusting the type and amount of each component constituting the adhesive.

[0061] It should be noted that the test samples used in the above-mentioned mass reduction rate measurements, elastic modulus measurements, and glass transition temperature measurements were obtained by completely curing the adhesive. Specifically, the test samples were obtained in a state where differential scanning calorimetry of the resulting cured product showed that the heat generated by the curing reaction was 0.1 mJ / mg or less at 25°C for 2 hours. Furthermore, for example, in the case of a two-component adhesive, curing can be achieved by simply mixing the first and second components and then leaving them at room temperature (25°C) for a long period of time (e.g., 7 days).

[0062] Viscosity

[0063] The adhesive of the present invention preferably has a viscosity of 300 Pa·s or less. It should be noted that the viscosity is measured using a rheometer, with the sample temperature adjusted to 25°C using a Peltier plate, and a φ25mm parallel plate, while continuously varying the shear rate within the range of 0.0001 to 100 (1 / s). The viscosity is a value at a shear rate of 3.16 (1 / s). As a rheometer, for example, The company's rheometer "MCR-302e".

[0064] It should be noted that when measuring the viscosity of a two-component curing adhesive after mixing the first and second components, the sample was immediately placed in the rheometer after mixing the first and second components, and the viscosity was quickly measured. On the other hand, when measuring the viscosity of the first and second components before mixing, the sample was placed in the rheometer and allowed to stand for 10 minutes before the viscosity was measured.

[0065] By setting the adhesive viscosity to 300 Pa·s or less, the adhesive can be easily applied to the adherend, improving workability. Furthermore, the adhesive can be easily filled even into narrow gaps. The viscosity is more preferably 250 Pa·s or less, and even more preferably 200 Pa·s or less. Furthermore, the viscosity can be, for example, 10 Pa·s or more. However, to prevent dripping when a certain amount of thermally conductive filler is filled, the viscosity is preferably 30 Pa·s or more, and more preferably 50 Pa·s or more.

[0066] <Adhesion Strength>

[0067] The adhesive of the present invention can ensure high bonding strength by making the bonding strength after curing large. Therefore, the bonding strength of the adhesive after curing is as high as possible, for example, more than 1MPa, preferably more than 2MPa, more preferably more than 3MPa, and further preferably more than 3.8MPa. The bonding strength of the adhesive after curing is as high as possible, but in practical terms, for example, less than 25MPa.

[0068] In addition, the adhesive of the present invention can ensure flexibility by making the elongation under the maximum load after curing above a certain value, thereby facilitating improvement in reliability, etc. The elongation under the maximum load after curing of the adhesive of the present invention is, for example, 0.5 mm or more, preferably 0.6 mm or more, more preferably 0.7 mm or more, and even more preferably 0.75 mm or more. In addition, the elongation under the maximum load is not particularly limited, but from the perspective of imparting a certain bonding strength, it is, for example, 3 mm or less, preferably 2 mm or less.

[0069] It should be noted that the bonding strength and elongation under the maximum load of the above-mentioned cured adhesive can be measured by the following test method. First, prepare two PET plates of 25mm×100mm and a thickness of 2mm. Then, the two prepared plates are overlapped at the ends with an adhesive and the adhesive is cured, thereby bonding the ends of the plates to obtain a measurement sample. It should be noted that the ends of the plates are bonded by a cured adhesive of 25mm×5mm and a thickness of 1mm. The obtained measurement sample is stretched in the longitudinal direction by a tensile testing machine, and the maximum load at this time is set as the bonding force, and the elongation of the cured product under the maximum load is set as the elongation under the maximum load. It is better to set the stretching speed to 10mm / second.

[0070] It should be noted that the adhesive should be completely cured between the PET sheets. Here, complete curing is as described above. For example, for a two-component adhesive, curing can be achieved by mixing the first and second components, applying them between the PET sheets, and then leaving them at room temperature (25°C) for 168 hours.

[0071] Thermal conductivity

[0072] The adhesive of the present invention preferably has a cured product with a thermal conductivity of 1.5 W / (m·K) or more, more preferably 1.7 W / (m·K) or more, and even more preferably 1.9 W / (m·K) or more. The adhesive has good thermal conductivity when the cured product has a thermal conductivity of more than these lower limits. Therefore, when used in a battery cell assembly, for example, the heat generated from the battery cell can be efficiently transferred to the module housing and the battery pack via the cured product of the adhesive (thermal conductive component), and an excessive increase in the temperature of the battery cell can be suppressed. The higher the thermal conductivity, the better, but in practical use, it is, for example, 7.0 W / m·K or less.

[0073] Thermal conductivity can be measured by a method according to ASTM D5470-06.

[0074] Specifically, the adhesive is arranged in a manner that covers the measuring die head on the heating element side and is more than the thickness at the time of measurement, and then sandwiched with a radiator, and compressed with a load of 30 psi until the thickness of the adhesive becomes 1.0 mm, 1.5 mm, and 2.0 mm, and the thermal resistance of each thickness is measured. The thickness can be adjusted with a spacer. Regarding the values ​​of these three thermal resistances, a graph with the horizontal axis being the thickness and the vertical axis being the thermal resistance value is made, and an approximate straight line at the three points is obtained by the least squares method. Furthermore, the slope of the approximate straight line is set to thermal conductivity.

[0075] [Adhesive]

[0076] The adhesive of the present invention includes a curable adhesive. The curable adhesive may be thermosetting, photocurable, or moisture curable, but is preferably thermosetting. Furthermore, the adhesive may be either a one-component curing type or a two-component curing type, but is preferably a two-component curing type.

[0077] Two-component curing agents are used by mixing a first component containing a main component with a second component containing a curing agent. Curing preferably begins when the first and second components are mixed. Therefore, for two-component curing agents, it is best to use a curing agent that cures when mixed with the main component of the first component. Furthermore, it is best to use a curing agent that cures at room temperature (25°C) when mixed with the main component of the first component.

[0078] The adhesive is preferably a urethane, silicone, acrylic, epoxy, or organic polymer having a hydrolyzable silyl group. Of these, epoxy, urethane, and organic polymer having a hydrolyzable silyl group are more preferred, with epoxy being even more preferred. The use of these specific adhesives facilitates adjustment of the mass reduction rate after thermal cycling testing and the elastic modulus at 80°C within the above-specified ranges.

[0079] Urethane adhesives

[0080] Here, the urethane adhesive can be, for example, a material composed of a polyol compound as a main agent and a polyisocyanate compound as a curing agent. Therefore, in the case of a two-component curing type, it is preferable that the first component contains a polyol compound and the second component contains a polyisocyanate compound.

[0081] Hereinafter, the urethane adhesive will be described in detail.

[0082] (Polyol compound)

[0083] The polyol compound used in the present invention is not particularly limited, and examples thereof include polyester polyols, polyether polyols, polycarbonate polyols, and polymer polyols.

[0084] The polyester polyol may be an aromatic ring-containing polyester polyol or an aliphatic polyester polyol. Examples of the polyester polyol include caprolactone polyols such as polyester polyols obtained by reacting polycarboxylic acids with polyols and poly-ε-caprolactone polyols obtained by ring-opening polymerization of ε-caprolactone.

[0085] Examples of the polycarboxylic acid serving as a raw material for the polyester polyol include dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, sebacic acid, and dodecanedicarboxylic acid.

[0086] Examples of the polyol used as a raw material for the polyester polyol include diols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, and cyclohexanediol.

[0087] Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytrimethylene glycol, polytetramethylene ether glycol, polymethyltetramethylene glycol, and polyalkylene glycols such as random copolymers or block copolymers of these alkylene glycols or derivatives thereof.

[0088] Furthermore, the polyether polyol may be a polyalkylene polyol obtained by ring-opening addition polymerization of an alkylene oxide (e.g., ethylene oxide, propylene oxide, butylene oxide, isobutylene oxide, etc.) with an initiator having two or more active hydrogen atoms. Specific examples of the initiator include aliphatic polyols, more specifically diols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexanediol, and cyclohexanedimethanol; triols such as trimethylolpropane and glycerol; tetrafunctional alcohols such as pentaerythritol; and high-functionality alcohols such as sucrose and sorbitol. Other examples include aliphatic amines such as alkylenediamines such as ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, and neopentyldiamine; alkanolamines such as monoethanolamine and diethanolamine; and aromatic amines such as aniline, toluenediamine, xylylenediamine, diphenylmethanediamine, and Mannich condensates. Furthermore, bisphenol-type polyalkylene polyols obtained by addition reaction of alkylene oxides with active hydrogen moieties of a bisphenol-type molecular skeleton may also be used.

[0089] Examples of the polycarbonate polyol include poly(3-methyl-1,5-pentamethylene carbonate) diol, polypentamethylene carbonate diol, and polytetramethylene carbonate diol.

[0090] Examples of the polymer polyol include polymers obtained by graft-polymerizing aromatic polyols, alicyclic polyols, aliphatic polyols, polyester polyols, and the like with ethylenically unsaturated compounds such as acrylonitrile, styrene, methyl acrylate, and methacrylate; and hydrogenated products of polybutadiene polyol.

[0091] Examples of aromatic polyols used in the production of polymer polyols include bisphenol A, bisphenol F, phenol novolac, and cresol novolac. Examples of alicyclic polyols used in the production of polymer polyols include cyclohexanediol, methylcyclohexanediol, isophorone diol, dicyclohexylmethanediol, and dimethyldicyclohexylmethanediol. Examples of aliphatic polyols used in the production of polymer polyols include ethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol.

[0092] As the polyol compound, among the above, polyether polyol is preferred, and polyalkylene glycol is more preferred. By using a polyether polyol, the storage modulus value can be easily reduced.

[0093] The average molecular weight of the polyol compound is not particularly limited, but is preferably 300 or greater, more preferably 500 or greater, and even more preferably 700 or greater. A high average molecular weight of the polyol compound facilitates a low storage modulus. Furthermore, the average molecular weight of the polyol compound is not particularly limited, but is, for example, 20,000 or less, preferably 10,000 or less, more preferably 5,000 or less, and even more preferably 3,500 or less.

[0094] In addition, the average molecular weight of the polyol compound may be determined by measuring the hydroxyl value (mgKOH / g) and using the following formula.

[0095] Average molecular weight = hydroxyl value × N × 1,000 / 56.11

[0096] N: average number of functional groups of the polyol

[0097] In addition, it is preferable that the hydroxyl value is measured according to JIS K 1557-1.

[0098] (Polyisocyanate compound)

[0099] Examples of the polyisocyanate compound include aromatic polyisocyanate compounds and aliphatic polyisocyanate compounds.

[0100] Examples of the aromatic polyisocyanate compound include diphenylmethane diisocyanate, toluene diisocyanate, and naphthalene-1,5-diisocyanate.

[0101] Examples of the aliphatic polyisocyanate compound include hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, norbornane diisocyanate, trans-cyclohexane-1,4-diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, cyclohexane diisocyanate, bis(isocyanatomethyl)cyclohexane, and dicyclohexylmethane diisocyanate.

[0102] The polyisocyanate compound may be a modified form as described above, a liquid modified form of diphenylmethane diisocyanate, polymeric MDI, or the like, or a biuret form, isocyanurate form, or adduct of the polyisocyanate compound.

[0103] The content of the polyol compound and the polyisocyanate compound in the adhesive is calculated as the molar ratio ([NCO] / [OH]) of the hydroxyl group (OH) in the polyol compound to the isocyanate group (NCO) in the polyisocyanate compound, and is preferably within a range of, for example, 1.0 to 4.0, and preferably 1.5 to 3.0. The molar ratio ([NCO] / [OH]) is also referred to as an equivalent ratio.

[0104] Silicone adhesives

[0105] Silicone adhesives can be either condensation-curable silicone resins or addition-curable silicone resins, with addition-curable silicone resins being preferred. Addition-curable silicone resins preferably consist of a silicone resin constituting a base and a curing agent that cures the base. For example, in the case of addition-curable silicone resins, an organopolysiloxane having an alkenyl group is preferably used as the base, and an organohydrogenpolysiloxane is preferably used as the curing agent.

[0106] <Organic polymer having a hydrolyzable silyl group>

[0107] Organic polymers having hydrolyzable silyl groups can form silanol groups by hydrolysis in the presence of moisture such as humidity. The silanol groups then undergo polycondensation with each other or with the hydrolyzable silyl groups to form siloxane bonds. This allows the organic polymer to form a crosslinked structure and cure to form a rubbery elastomer. It should be noted that the term "silanol group" refers to a hydroxyl group (Si-OH) directly bonded to a silicon atom.

[0108] A hydrolyzable silyl group is a group formed by bonding one to three hydrolyzable groups to a silicon atom. The hydrolyzable group of a hydrolyzable silyl group is not particularly limited, and examples thereof include a hydrogen atom, a halogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an acid amide group, an aminooxy group, a mercapto group, and an alkenyloxy group.

[0109] Among them, alkoxysilyl groups are preferred as hydrolyzable silyl groups due to their mild hydrolysis reaction. Examples of the alkoxysilyl group include trialkoxysilyl groups such as trimethoxysilyl, triethoxysilyl, triisopropoxysilyl, and triphenoxysilyl; dialkoxysilyl groups such as dimethoxymethylsilyl and diethoxymethylsilyl; and monoalkoxysilyl groups such as methoxydimethylsilyl and ethoxydimethylsilyl. Among these, dialkoxysilyl groups are more preferred, and dimethoxymethylsilyl groups are particularly preferred.

[0110] The main chain of the organic polymer having a hydrolyzable silyl group may be linear or branched, but is preferably linear. That is, the organic polymer having a hydrolyzable silyl group of the present invention preferably has a hydrolyzable silyl group at the end of the linear main chain.

[0111] When an organic polymer having a hydrolyzable silyl group at a terminal is used, the cured product can be easily elongated and the conformability can be improved.

[0112] The terminal silylation rate of the organic polymer having a hydrolyzable silyl group is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more. If the terminal silylation rate is above a certain level, it is easy to appropriately adjust the curability and elongation of the battery-curable adhesive. It should be noted that the so-called terminal silylation rate refers to the ratio of silylated terminals to all terminals of the organic polymer having a hydrolyzable silyl group.

[0113] The upper limit of the terminal silylation rate is not particularly limited, but is, for example, 100% or less, and can be practically 99% or less.

[0114] It should be noted that the terminal silylation rate of the organic polymer having a hydrolyzable silyl group is determined by 1 H-NMR was obtained.

[0115] The average number of hydrolyzable silyl groups in one molecule of the organic polymer having a hydrolyzable silyl group is preferably 1 to 3. When the number of hydrolyzable silyl groups in the polymer is within this range, the curability and elongation of the adhesive are improved.

[0116] It should be noted that the average number of hydrolyzable silyl groups in one molecule of an organic polymer having a hydrolyzable silyl group can be determined by 1 The concentration of the hydrolyzable silyl group in the organic polymer determined by H-NMR and the number average molecular weight of the polymer determined by GPC were used for calculation.

[0117] The method for introducing a hydrolyzable silyl group into an organic polymer is not particularly limited, and examples thereof include: (1) a method of allowing a hydrosilane having a hydrolyzable silyl group to react with an organic polymer having an unsaturated group modified in its molecule to perform hydrosilylation; (2) a method of reacting a compound having a mercapto group and a hydrolyzable silyl group with an organic polymer having an unsaturated group modified in its molecule; (3) a method of reacting an organic polymer having a functional group in its molecule with a compound having a functional group reactive with the functional group and a hydrolyzable silyl group; and the like. Specifically, the reaction between an isocyanate group and a hydroxyl group, the reaction between an isocyanate group and an amino group, the reaction between an isocyanate group and a mercapto group, and the like can be utilized.

[0118] The organic polymer containing a hydrolyzable silyl group is not particularly limited, and examples thereof include polyoxyalkylenes such as polyethylene oxide, polypropylene oxide, polybutylene oxide, polytetramethylene oxide, polyethylene oxide-polypropylene oxide copolymers, polypropylene oxide-polybutylene oxide copolymers, saturated hydrocarbon polymers, polychloroprene, polyisoprene, copolymers of isoprene or butadiene with acrylonitrile and / or styrene, copolymers of polybutadiene, isoprene or butadiene with acrylonitrile and / or styrene, (meth)acrylate polymers obtained by radical polymerization of monomers such as ethyl (meth)acrylate and butyl (meth)acrylate, and copolymers of monomers such as vinyl acetate, acrylonitrile, and styrene. Polyamide polymers include vinyl polymers obtained by free radical polymerization, graft polymers obtained by polymerizing vinyl monomers into the above polymers, polysulfide polymers, nylon 6 obtained by ring-opening polymerization of ε-caprolactam, nylon 6,6 obtained by polycondensation of 1,6-hexanediamine and adipic acid, nylon 6,10 obtained by polycondensation of 1,6-hexanediamine and sebacic acid, nylon 11 obtained by polycondensation of ε-aminoundecanoic acid, nylon 12 obtained by ring-opening polymerization of ε-aminolaurolactam, copolymerized nylons containing two or more of the above nylons, polycarbonate polymers produced by polycondensation of bisphenol A and phosgene, and diallyl phthalate polymers. It should be noted that in this specification, (meth)acrylate refers to methacrylate or acrylate.

[0119] Among these, polyoxyalkylenes are preferred as organic polymers from the viewpoint of achieving desired shear adhesive strength and elongation at maximum stress after curing. Specifically, polyoxyalkylenes having a hydrolyzable silyl group are preferred as organic polymers. Polyoxypropylene is particularly preferred among polyoxyalkylenes.

[0120] The number average molecular weight (Mn) of the hydrolyzable silyl group-containing organic polymer is preferably 1,000 to 70,000, more preferably 1,000 to 40,000, even more preferably 1,500 to 30,000, even more preferably 2,000 to 30,000, even more preferably 4,000 to 30,000, and even more preferably 4,000 to 20,000. If the number average molecular weight of the hydrolyzable silyl group-containing organic polymer is below these upper limits, the viscosity of the resulting adhesive can be reduced. Furthermore, if the number average molecular weight of the hydrolyzable silyl group-containing organic polymer is above these lower limits, the cured adhesive is prevented from becoming brittle, and the hardness and elongation of the cured product are improved.

[0121] In addition, when the adhesive contains a plurality of hydrolyzable silyl group-containing organic polymers, the number average molecular weight (Mn) mentioned above refers to the number average molecular weight (Mn) of the entirety of these polymers.

[0122] It should be noted that, in the present invention, the number average molecular weight of the organic polymer containing a hydrolyzable silyl group refers to a value measured by GPC (gel permeation chromatography) in terms of polystyrene. In the measurement using the GPC method, for example, the "ACQUITY APC system" manufactured by Waters can be used. Shodex KF604 was used as the GPC column, tetrahydrofuran was used as the solvent, the column temperature was set at 40° C., and the measurement was performed at a flow rate of 0.3 ml / min.

[0123] The polymer containing a hydrolyzable silyl group can be a commercially available product. For example, as a polyoxyalkylene polymer having a main chain skeleton of polyoxypropylene and a dimethoxysilyl group at the end of the main chain skeleton, there is a product called " A2410"," S4530", The company's product names are "S203", "SAT350", "SAX010", etc.

[0124] Acrylic adhesives

[0125] Acrylic adhesives may be any component that forms an acrylic polymer upon curing, and examples thereof include various acrylic compounds such as alkyl (meth)acrylates, hydroxyalkyl (meth)acrylates, (meth)acrylic acid, (meth)acrylamides, and urethane (meth)acrylates. Furthermore, acrylic adhesives may contain vinyl monomers copolymerizable with the aforementioned acrylic compounds. Furthermore, at least a portion of the acrylic adhesive may be a polymer of an acrylic compound, a copolymer of an acrylic compound and a vinyl monomer, or the like. Furthermore, the acrylic adhesive may be a monofunctional acrylate compound or a multifunctional acrylate compound.

[0126] Epoxy adhesives

[0127] The epoxy adhesive is preferably composed of a compound containing an epoxy group as a main agent and a curing agent. The following describes in detail the case where an epoxy adhesive is used as the adhesive.

[0128] (Compounds containing epoxy groups)

[0129] As described above, when the adhesive is epoxy-based, it is preferred that the adhesive contain a compound containing an epoxy group. The use of a compound containing an epoxy group facilitates increasing the adhesive strength of the adhesive and also facilitates adjusting the elastic modulus of the cured adhesive to within a specified range. The compound containing an epoxy group may be a compound containing a polyfunctional epoxy group or a compound containing a monofunctional epoxy group.

[0130] The adhesive of the present invention preferably contains at least a compound containing a polyfunctional epoxy group. The adhesive containing the compound containing a polyfunctional epoxy group can easily increase the bonding strength.

[0131] The adhesive more preferably contains a monofunctional epoxy group-containing compound in addition to the polyfunctional epoxy group-containing compound. By further containing a monofunctional epoxy group-containing compound, the adhesive prevents excessively high crosslinking density after curing, thereby facilitating a low elastic modulus after curing. Furthermore, the use of a monofunctional epoxy group-containing compound facilitates low viscosity of the adhesive before curing.

[0132] Examples of the polyfunctional epoxy group-containing compound include bifunctional and trifunctional compounds, with bifunctional epoxy group-containing compounds being preferred. Specific examples of the polyfunctional epoxy group-containing compound include epoxy resins having aromatic skeletons, such as phenol novolac epoxy resins, resorcinol epoxy resins, epoxy resins having a bisphenol skeleton, epoxy resins having a naphthalene skeleton, epoxy resins having a fluorene skeleton, epoxy resins having a biphenyl skeleton, epoxy resins having a bis(glycidyloxyphenyl)methane skeleton, epoxy resins having a xanthene skeleton, epoxy resins having an anthracene skeleton, and epoxy resins having a pyrene skeleton.

[0133] In addition, epoxy resins having an alicyclic skeleton, such as an epoxy resin having a dicyclopentadiene skeleton and an epoxy resin having an adamantane skeleton, can also be mentioned.

[0134] Furthermore, aliphatic epoxy resins such as butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, and trimethylolpropane polyglycidyl ether can also be mentioned.

[0135] Furthermore, hydrogenated products or modified products of the above-exemplified epoxy resins can also be used as the epoxy resin.

[0136] Examples of the epoxy resin having a bisphenol skeleton include epoxy resins having a bisphenol skeleton of bisphenol A type, bisphenol F type, or bisphenol S type.

[0137] Examples of the resorcinol-type epoxy resin include resorcinol diglycidyl ether.

[0138] Examples of the epoxy resin having a naphthalene skeleton include 1,2-diglycidylnaphthalene, 1,5-diglycidylnaphthalene, 1,6-diglycidylnaphthalene, 1,7-diglycidylnaphthalene, 2,7-diglycidylnaphthalene, triglycidylnaphthalene, and 1,2,5,6-tetraglycidylnaphthalene.

[0139] Examples of the epoxy resin having a fluorene skeleton include 9,9-bis(4-glycidyloxyphenyl)fluorene, 9,9-bis(4-glycidyloxy-3-methylphenyl)fluorene, 9,9-bis(4-glycidyloxy-3-chlorophenyl)fluorene, 9,9-bis(4-glycidyloxy-3-bromophenyl)fluorene, 9,9-bis(4-glycidyloxy-3-fluorophenyl)fluorene, 9,9-bis(4-glycidyloxy-3-methoxyphenyl)fluorene, 9,9-bis(4-glycidyloxy-3,5-dimethylphenyl)fluorene, 9,9-bis(4-glycidyloxy-3,5-dichlorophenyl)fluorene, and 9,9-bis(4-glycidyloxy-3,5-dibromophenyl)fluorene.

[0140] Examples of the epoxy resin having a biphenyl skeleton include 4,4′-diglycidylbiphenyl and 4,4′-diglycidyl-3,3′,5,5′-tetramethylbiphenyl. Examples of the epoxy resin having a bis(glycidyloxyphenyl)methane skeleton include 1,1'-bis(2,7-glycidyloxynaphthyl)methane, 1,8'-bis(2,7-glycidyloxynaphthyl)methane, 1,1'-bis(3,7-glycidyloxynaphthyl)methane, 1,8'-bis(3,7-glycidyloxynaphthyl)methane, 1,1'-bis(3,5-glycidyloxynaphthyl)methane, 1,8'-bis(3,5-glycidyloxynaphthyl)methane, 1,2'-bis(2,7-glycidyloxynaphthyl)methane, 1,2'-bis(3,7-glycidyloxynaphthyl)methane, and 1,2'-bis(3,5-glycidyloxynaphthyl)methane.

[0141] Examples of the epoxy resin having a xanthene skeleton include 1,3,4,5,6,8-hexamethyl-2,7-bis-glycidylmethoxy-9-phenyl-9H-xanthene, etc. Examples of the epoxy resin having an anthracene skeleton include those having one or more anthracene skeletons and two or more epoxy groups or glycidyl groups in one molecule.

[0142] Examples of the epoxy resin having a pyrene skeleton include those having one or more pyrene skeletons and two or more epoxy groups or glycidyl groups in one molecule.

[0143] Examples of the epoxy resin having a dicyclopentadiene skeleton include dicyclopentadiene dioxide and phenol novolac epoxy resins having a dicyclopentadiene skeleton. Examples of the epoxy resin having an adamantane skeleton include 1,3-bis(4-glycidyloxyphenyl)adamantane and 2,2-bis(4-glycidyloxyphenyl)adamantane.

[0144] As the bifunctional epoxy group-containing compound, among the above, epoxy resins having an aromatic skeleton are preferred from the viewpoint of improving adhesive strength and reliability. Among them, bisphenol-type epoxy resins, which are epoxy resins having a bisphenol skeleton, are preferred.

[0145] The bifunctional epoxy group-containing compound may be used alone or in combination of two or more.

[0146] Examples of monofunctional epoxy group-containing compounds include phenyl glycidyl ethers such as alkylphenyl glycidyl ethers represented by phenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, cresyl glycidyl ether, and nonylphenyl glycidyl ether, and monofunctional epoxy group-containing compounds having an aromatic ring such as 1-glycidyl naphthalene and 2-glycidyl naphthalene. Examples of monofunctional epoxy group-containing compounds include aliphatic monofunctional epoxy group-containing compounds, specifically glycidyl ethers of aliphatic alcohols such as butyl glycidyl ether and lauryl glycidyl ether.

[0147] From the viewpoint of improving adhesive strength and reliability, the monofunctional epoxy group-containing compound preferably has an aromatic ring, and among them, phenyl glycidyl ether is preferred.

[0148] The monofunctional epoxy group-containing compound may be used alone or in combination of two or more.

[0149] The epoxy-containing compound preferably has a low molecular weight. This allows for lower adhesive viscosity and higher thermal conductive filler loading. For this reason, epoxy-containing compounds with a molecular weight of, for example, 1000 or less are preferred. The lower limit of the molecular weight of the epoxy-containing compound is not particularly limited, but is, for example, 100 or greater.

[0150] Here, the molecular weight of the polyfunctional epoxy group-containing compound is preferably 1000 or less, more preferably 750 or less, and even more preferably 500 or less, and is preferably 200 or more, more preferably 250 or more, and even more preferably 280 or more.

[0151] The molecular weight of the monofunctional epoxy group-containing compound is preferably 500 or less, more preferably 300 or less, and further preferably 200 or less, and is preferably 100 or more, more preferably 125 or more, and further preferably 140 or more.

[0152] The epoxy equivalent of the epoxy group-containing compound is preferably 500 g / eq or less, more preferably 375 g / eq or less, further preferably 250 g / eq or less, and is preferably 100 g / eq or more, more preferably 125 g / eq or more, further preferably 140 g / eq or less.

[0153] The epoxy group-containing compound is preferably liquid at room temperature (25°C). Furthermore, from the perspective of reducing viscosity, the viscosity of the epoxy group-containing compound at 25°C is preferably as low as possible, for example, 50 Pa·s or less, preferably 10 Pa·s or less. The viscosity of the epoxy group-containing compound at 25°C is not particularly limited, and for example, may be 0.5 mPa·s or more, or 1 mPa·s or more.

[0154] The viscosity of the polyfunctional epoxy group-containing compound at 25°C may be, for example, 50 Pa·s or less, preferably 10 Pa·s or less, and may be 1 mPa·s or more. In practical terms, it is preferably 10 mPa·s or more, more preferably 100 mPa·s or more.

[0155] On the other hand, the viscosity of the monofunctional epoxy group-containing compound at 25°C may be, for example, 10 Pa·s or less, preferably 1 Pa·s or less, and more preferably 100 mPa·s or less. Furthermore, for example, it may be 0.5 mPa·s or more, 1 mPa·s or more, or 3 mPa·s or more. It should be noted that when the adhesive contains both a polyfunctional epoxy group-containing compound and a monofunctional epoxy group-containing compound, the viscosity of the monofunctional epoxy group-containing compound is preferably lower than that of the polyfunctional epoxy group-containing compound.

[0156] It should be noted that the viscosity of the epoxy group-containing compound and the curing agent described later can be measured using a rheometer (e.g., The sample temperature was adjusted to 25°C using a Peltier plate. A 50 mm φ cone plate with a 1° angle was used, and the shear rate was continuously varied within the range of 10 to 100 1 / sec. The viscosity values ​​mentioned above are those at a shear rate of 10 1 / sec.

[0157] (Curing Agent)

[0158] The adhesive preferably contains a curing agent that cures the main agent. Specifically, it preferably contains at least one of an amine and a thiol. At least one of the amine and the thiol is preferably used when the adhesive contains a compound containing an epoxy group. By containing an amine or a thiol as a curing agent, the adhesive can be easily adjusted to a practical curing rate at room temperature. Furthermore, the adhesive also tends to have high bonding strength.

[0159] The amine may be a polyamine such as a diamine or a triamine, or a monoamine, but is preferably a polyamine such as a diamine or a triamine. Specific examples of the amine include polyoxyalkyleneamines such as polyoxyethylenediamine, poly(oxyethylene / oxypropylene)diamine, polyoxypropylenediamine, poly(oxybutylene / oxypropylene)diamine, polyethylene glycol bis(propylamine), trimethylolpropane poly(oxypropylene)triamine, glyceryl poly(oxypropylene)triamine, and methoxy poly(oxyethylene / oxypropylene)-2-propylamine; meta-phenylenediamine, para-phenylenediamine, meta-phenylenediamine, para-phenylenediamine, toluene-2,4-diamine, toluene-2,6-diamine, mesitylene-2,4-diamine, mesitylene-2,6-diamine, 3,5-diethyltoluene-2,4-diamine, 3,5-diethyltoluene-2,6-diamine, benzyldiamine, 4,4-diaminodiphenylmethane, 2,5-diaminodiphenylmethane, and the like. Aromatic ring-containing amines such as naphthalene diamine, 2,6-naphthalene diamine, reaction products of m-xylylenediamine and styrene, phenalkamines, 1,6-hexanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,14-tetradecanediamine, 1,16-hexadecanediamine, 1,18-octadecanediamine, 1,20-eicosanediamine, 2-methyl-1,8-octanediamine, 2-methyl-1,9-nonanediamine, and 2,7-dimethyl-1,8-octanediamine, alicyclic amines such as 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, cyclohexanediamine, methylcyclohexanediamine, and isophoronediamine, and polyamidoamines.

[0160] Examples of the polyamidoamine include those obtained by reacting aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, and azelaic acid, fatty acids, and carboxylic acid compounds such as dimer acid with aliphatic polyamines and polyamines having a polyoxyalkylene chain.

[0161] Examples of thiols include polythiols such as dithiols and trithiols. Specific examples of thiols include esters of polyols such as pentaerythritol tetrakis(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, and trimethylolpropane tris(3-mercaptobutyrate) with mercapto organic acids; aliphatic thiols such as alkanedithiol; and aromatic ring-containing thiols such as xylylenedithiol.

[0162] Amines and thiols with high molecular weights are preferably used. Using high molecular weight amines and thiols prevents volatilization of unreacted amines and thiols during thermal cycling tests, minimizing the mass loss after thermal cycling tests. Therefore, even when thermal cycling tests are performed on cured products, volatilization marks can be prevented, improving reliability.

[0163] Specifically, as high molecular weight amines and thiols, those with a molecular weight of 350 or more, preferably 380 or more, and more preferably 400 or more are preferably used. In addition, the upper limit of the molecular weight of amines and thiols is not particularly limited, and is, for example, 1000 or less, preferably 800 or less, and more preferably 700 or less.

[0164] Furthermore, the high molecular weight amines and thiols preferably have a viscosity greater than a certain value. Specifically, the viscosity at 25° C. is preferably 1 Pa·s or greater, more preferably 3 Pa·s or greater, and even more preferably 5 Pa·s or greater. The upper limit is not particularly limited, but from the perspective of reducing the viscosity of the adhesive, it is, for example, 50 Pa·s or less, preferably 30 Pa·s or less, and more preferably 20 Pa·s or less.

[0165] Specifically, among the above-mentioned amines and thiols with high molecular weight, preferably at least any one of polyoxyalkyleneamines, polyamide amines, and esters of polyols and mercapto organic acids is used, among which polyoxyalkyleneamines are more preferred, and trimethylolpropane poly(oxypropylene)triamine and methoxy poly(oxyethylene / oxypropylene)-2-propylamine are particularly preferred.

[0166] Furthermore, even when using high-molecular-weight amines and thiols, it is also preferable to use low-molecular-weight amines and thiols in combination. By using amines or thiols of varying molecular weight, epoxy-containing compounds can be cured in a variety of curing modes, and even when using low-molecular-weight components, unreacted components are less likely to form. For example, a low-molecular-weight monofunctional epoxy-containing compound can react appropriately with a low-molecular-weight, fast-curing amine or thiol, while a high-molecular-weight polyfunctional epoxy-containing compound can react appropriately with a high-molecular-weight, slow-curing amine or thiol, allowing the curing reaction to proceed smoothly.

[0167] The molecular weight of the low molecular weight amine and thiol is lower than that of the high molecular weight amine and thiol. Specifically, it is preferable to use a substance having a molecular weight of less than 350, more preferably 300 or less, and even more preferably 270 or less. In addition, there is no particular limitation on the lower limit of the molecular weight of the low molecular weight amine and thiol, but it is, for example, 100 or more, preferably 120 or more, and more preferably 130 or more.

[0168] When low molecular weight amines and thiols are used in combination with high molecular weight amines and thiols, the elastic modulus at 80° C. and the adhesive strength can be appropriately adjusted by adjusting the blending amounts of the low molecular weight amines and thiols.

[0169] Furthermore, it is preferred that the viscosity of the low molecular weight amines and thiols mentioned above be below a certain value. Specifically, the viscosity at 25°C is preferably less than 1 Pa·s, more preferably 500 mPa·s or less, and even more preferably 100 mPa·s or less. There is no particular lower limit, but from the perspective of reducing the viscosity of the adhesive, it can be, for example, 1 mPa·s or more, or 3 mPa·s or more.

[0170] The molecular weights of amines, thiols, and the aforementioned epoxy group-containing compounds can be measured, for example, using a mass spectrometer (GC-MS or LC-MS).

[0171] Specifically, among the amines and thiols having a low molecular weight, amines containing an aromatic ring are preferred. Among them, meta-xylylenediamine and a reaction product of meta-xylylenediamine and styrene are preferred.

[0172] The amount of low-molecular-weight amines and thiols relative to the total amount of amines and thiols contained in the adhesive can be, for example, 55% by mass or less, preferably 50% by mass or less, and more preferably 35% by mass or less. By keeping the amount of low-molecular-weight amines and thiols below a certain level, the mass loss rate after thermal cycling testing can be easily suppressed. Furthermore, it is also easier to improve adhesive strength and other aspects.

[0173] The amount of low-molecular-weight amines and thiols relative to the total amines and thiols contained in the adhesive can be 0% by mass or greater, preferably 5% by mass or greater, more preferably 10% by mass or greater, and even more preferably 15% by mass or greater. By keeping the amount of low-molecular-weight amines and thiols below a certain level, the rate of mass loss after thermal cycling testing can be suppressed. Furthermore, adhesive strength and other properties can be improved.

[0174] The active hydrogen equivalent of the amine and thiol contained in the adhesive is not particularly limited, and is, for example, 15 g / eq or more, preferably 25 g / eq or more, more preferably 30 g / eq or more, and is, for example, 250 g / eq or less, preferably 200 g / eq or less, more preferably 150 g / eq or less.

[0175] In the present invention, when an epoxy-based adhesive is used, in addition to the epoxy-containing compound, a multifunctional acrylate compound may be further contained as a base agent. Specifically, the adhesive may be composed of an epoxy-containing compound as a base agent and a curing agent such as an amine, or may be composed of an epoxy-containing compound as a base agent and a multifunctional acrylate compound, and a curing agent such as an amine.

[0176] The polyfunctional acrylate compounds used in combination with the epoxy group-containing compound are as follows.

[0177] (Multifunctional acrylate compound)

[0178] The polyfunctional acrylate compound is a compound having two or more functional groups (ie, the number of (meth)acryloyl groups). The polyfunctional acrylate compound reacts rapidly with the curing agent, particularly amine, and imparts a certain degree of adhesive strength in the initial stage of curing.

[0179] As the polyfunctional acrylate compound, polyfunctional (meth)acrylate is preferably used, and esters of polyfunctional polyol and (meth)acrylic acid are more preferably used.

[0180] In the present specification, “(meth)acryloyl” refers to either acryloyl or methacryloyl, and “(meth)acrylate” refers to either acrylate or methacrylate, and the same applies to other similar terms.

[0181] Examples of bifunctional polyfunctional acrylate compounds include 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 2-n-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, dimethyloltricyclodecane di(meth)acrylate, ethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and dipropylene glycol di(meth)acrylate. di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, ethylene oxide-added bisphenol A di(meth)acrylate, propylene oxide-added bisphenol A di(meth)acrylate, ethylene oxide-added bisphenol F di(meth)acrylate, dimethylol dicyclopentadienyl di(meth)acrylate, ethylene oxide-modified isocyanuric acid di(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl (meth)acrylate, carbonate diol di(meth)acrylate, polyether diol di(meth)acrylate, polyester diol di(meth)acrylate, polycaprolactone diol di(meth)acrylate, polybutadiene diol di(meth)acrylate, and the like.

[0182] Examples of the trifunctional or higher-functional acrylate compounds include trimethylolpropane tri(meth)acrylate, glycerol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, pentaerythritol alkoxy tetra(meth)acrylate, ethylene oxide-added trimethylolpropane tri(meth)acrylate, propylene oxide-added trimethylolpropane tri(meth)acrylate, and caprolactone-modified trimethylolpropane tri(meth)acrylate. acrylate, ethylene oxide added isocyanurate tri(meth)acrylate, propylene oxide added glycerol tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, alkylene oxide added pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol octa(meth)acrylate, four pentaerythritol deca(meth)acrylate, tripentaerythritol hepta(meth)acrylate, four pentaerythritol nona(meth)acrylate, and the like.

[0183] The number of functional groups in the multifunctional acrylate compound is preferably 3 or more, more preferably 4 or more, and even more preferably 6 or more. A larger number of functional groups in the multifunctional acrylate compound tends to improve the adhesive strength in the initial stage of curing. It should be noted that the upper limit of the number of functional groups in the multifunctional acrylate compound is not particularly limited, and for example, it may be 10 or less, or 8 or less.

[0184] From the perspective of lowering the viscosity of the adhesive before curing, the molecular weight of the multifunctional acrylate compound is preferably below a certain value. Specifically, the molecular weight of the multifunctional acrylate compound can be, for example, 5000 or less, preferably 3000 or less, more preferably 1000 or less, and even more preferably 700 or less. Furthermore, it is preferable to use a multifunctional acrylate compound having a molecular weight of, for example, 150 or greater, preferably 200 or greater, more preferably 250 or greater, and even more preferably 450 or greater. By keeping the molecular weight of the multifunctional acrylate compound above a certain value, it is possible to prevent the crosslinking density from being excessively high, thereby facilitating good elongation and adhesive strength.

[0185] From the viewpoint of easily lowering the viscosity of the adhesive before curing, the polyfunctional acrylate compound is preferably liquid at room temperature (25° C.).

[0186] The functional group equivalent weight of the multifunctional acrylate compound is not particularly limited, but is preferably 500 g / eq or less, more preferably 300 g / eq or less, and even more preferably 150 g / eq or less. It is also preferably 75 g / eq or more, more preferably 80 g / eq or more, and even more preferably 85 g / eq or more.

[0187] In the adhesive, the ratio of the number of functional groups of the multifunctional acrylate compound to the number of functional groups of the epoxy group-containing compound may be approximately 0.1 to 1.5, preferably 0.2 to 1.2, more preferably 0.3 to 1.0, and even more preferably 0.4 to 0.85.

[0188] The content of the multifunctional acrylate compound is, for example, 10% by mass or less, preferably 8% by mass or less, based on the total amount of the thermally conductive composition. If the content of the multifunctional acrylate compound is below the upper limit, excessive initial curing by the multifunctional acrylate compound is prevented, thereby easily extending the service life. Furthermore, if the content of the multifunctional acrylate compound is reduced, moisture resistance is also improved. Therefore, for example, even after curing and prolonged use under high temperature and high humidity conditions, high bond strength can be maintained. The content of the multifunctional acrylate compound is more preferably 6% by mass or less, and even more preferably 4% by mass or less.

[0189] Furthermore, in order to exhibit rapid curing properties and thus increase the adhesive strength in the initial stage of curing, the content of the multifunctional acrylate compound is preferably a certain amount or more, for example, 0.3% by mass or more, preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 1.5% by mass or more, based on the total amount of the adhesive.

[0190] In the present invention, when using amines, it is preferably adjusted so that one NH group among the active hydrogen groups (NH) constituting the amino group contributes to the curing reaction, and a certain amount of NH groups remain. This allows the adhesive to be adjusted so that the three-dimensional crosslinking in the cured product does not become excessively dense and the elastic modulus does not increase. Furthermore, adjusting the amount of NH groups so that more NH groups remain can increase the polarity of the cured product and improve the adhesion to the resin. Therefore, by adjusting the amount of NH groups remaining, the adhesion to the resin can be adjusted.

[0191] When using thiols, it is also advisable to adjust the adhesive so that a certain amount of SH remains. This prevents the three-dimensional crosslinks in the cured product from becoming too dense and the elastic modulus from increasing. Furthermore, by allowing SH to remain, the adhesive strength to metals can be improved.

[0192] It should be noted that when a thiol is used as a curing agent, it is preferably used in combination with the above-mentioned amine, or at least one of a compound containing a trifunctional or higher epoxy group and a trifunctional or higher thiol is preferably used. This allows adjustment so that the elastic modulus does not decrease excessively. In addition, by adjusting the residual SH group content, the adhesion to metal can be adjusted.

[0193] From the viewpoint of improving adhesion to both resins and metals, it is preferred to adjust the composition so that a certain amount of active hydrogen groups (NH and SH) remain by using an amine and a thiol in combination.

[0194] Specifically, the content of the epoxy group-containing compound and the amine content in the adhesive are preferably adjusted as follows.

[0195] The equivalent ratio of the number of epoxy groups in the epoxy-containing compound to the number of active hydrogen atoms in the amino group contained in the amine [(number of active hydrogen atoms in the amino group) / number of epoxy groups] = 1.2 or more and 2.9 or less

[0196] When the equivalent ratio is 1.2 or greater, the elastic modulus can be easily lowered even when a low-molecular-weight adhesive component is used, making it easier to adjust the elastic modulus at 80°C to the specified range. Furthermore, when the equivalent ratio is 2.9 or less, the elastic modulus is prevented from being excessively lowered, thereby preventing a decrease in adhesive strength, etc. The equivalent ratio is more preferably 1.6 or greater, even more preferably 2.0 or greater, and more preferably 2.8 or less, even more preferably 2.7 or less.

[0197] In addition, when the adhesive contains an epoxy-containing compound having a bifunctional epoxy-containing compound as the main component (for example, the ratio of the bifunctional epoxy-containing compound among all the epoxy-containing compounds is 50% by mass or more), and a trifunctional or higher polyfunctional thiol, the content of the epoxy-containing compound and the content of the polyfunctional thiol are preferably adjusted as follows.

[0198] The equivalent ratio of the number of epoxy groups in the epoxy-containing compound to the number of active hydrogen atoms in the thiol group [(number of active hydrogen atoms in the thiol group) / number of epoxy groups] = 1.3 or more and 2.6 or less

[0199] When the equivalent ratio is 1.3 or greater, the elastic modulus can be easily lowered even when a low-molecular-weight adhesive component is used, making it easier to adjust the elastic modulus at 80°C to the specified range. Furthermore, when the equivalent ratio is 2.6 or less, the elastic modulus is prevented from being excessively lowered, thereby preventing a decrease in adhesive strength, etc. The equivalent ratio is more preferably 1.35 or greater, even more preferably 1.4 or greater, and more preferably 2.5 or less, even more preferably 2.25 or less.

[0200] When the adhesive contains an epoxy-containing compound having a trifunctional or higher polyfunctional epoxy group-containing compound as a main component (for example, the ratio of the trifunctional or higher polyfunctional epoxy group-containing compound among all epoxy-containing compounds is 50% by mass or more), and a bifunctional thiol, the content of the polyfunctional epoxy group-containing compound and the content of the thiol are preferably adjusted as follows.

[0201] The equivalent ratio of the number of epoxy groups in the epoxy-containing compound to the number of active hydrogen atoms in the thiol group [(number of active hydrogen atoms in the thiol group) / number of epoxy groups] = 0.50 or more and 0.99 or less

[0202] When the equivalent ratio is 0.50 or greater, the elastic modulus is prevented from being excessively lowered beyond necessity, thereby preventing a decrease in adhesive strength, etc. Furthermore, when the equivalent ratio is 0.99 or less, the elastic modulus is easily lowered even when a low-molecular-weight adhesive component is used, making it easier to adjust the elastic modulus at 80°C to within a specified range. The equivalent ratio is more preferably 0.55 or greater, even more preferably 0.60 or greater, and more preferably 0.95 or less, even more preferably 0.90 or less.

[0203] The above describes the preferred equivalent ratios corresponding to the types of epoxy compounds, amines, and thiols. However, even with combinations other than those described above, by adjusting the equivalent ratios, it is possible to prevent the elastic modulus from being excessively lowered beyond necessity, thereby preventing the adhesive strength, etc. from being reduced. Furthermore, even when using a low-molecular-weight adhesive component, the elastic modulus tends to be lowered, and the elastic modulus at 80°C can be adjusted to be within the specified range.

[0204] It should be noted that the number of epoxy groups refers to the total number of epoxy groups contained in the adhesive, and is, for example, a value obtained by multiplying the number of epoxy groups per unit amount (mol / g) of the epoxy-containing compound contained in the adhesive by the content of the epoxy-containing compound. However, when two or more epoxy-containing compounds are contained, the value is the sum of the values ​​obtained by multiplying the number of epoxy groups per unit amount (mol / g) of each epoxy-containing compound by the content of each epoxy-containing compound.

[0205] The term "number of active hydrogen atoms in the amino group" refers to the total number of active hydrogen atoms in the amino group contained in the adhesive. For example, it is the value obtained by multiplying the number of active hydrogen atoms per unit amount (mol / g) of the amine in the adhesive by the amine content. However, when two or more amines are contained in the adhesive, the value is the sum of the values ​​obtained by multiplying the number of active hydrogen atoms per unit amount (mol / g) of each amine by the amine content. It should be noted that the number of active hydrogen atoms in the amine is 1 for NHR2 and 2 for NH2R (where R in NHR2 and NH2R represents a functional group other than active hydrogen atoms, i.e., the portion of the amine other than the NH or NH2).

[0206] The number of epoxy groups per unit amount of epoxy resin (mol / g) and the number of active hydrogen per unit amount of amine (mol / g) can be calculated from, for example, the epoxy equivalent (g / eq) and the active hydrogen equivalent (g / eq), respectively.

[0207] Here, the epoxy equivalent can be obtained by dividing the molecular weight of the compound containing epoxy groups by the number of epoxy groups per molecule. In addition, the active hydrogen equivalent can be obtained by dividing the molecular weight of the amine by the number of active hydrogens per molecule. The molecular weight, the number of epoxy groups, and the number of active hydrogens can be measured using a mass spectrometer (GC-MS or LC-MS). In addition, when only the molecular weight can be determined using a mass spectrometer, the number of epoxy groups and the number of active hydrogens per molecule can be determined using NMR ( 1 However, when the sample is a mixture, it is preferred to separate the components by GPC (gel permeation chromatography) or HPLC (high performance liquid chromatography) and then measure NMR.

[0208] It should be noted that when the structural formula of an epoxy-containing compound is known, the molecular weight and the number of epoxy groups are those that can be calculated from the structural formula. Furthermore, when the structural formula of an amine is known, the molecular weight and the number of active hydrogen atoms are those that can be calculated from the structural formula.

[0209] The number of active hydrogen atoms in thiol groups refers to the total number of active hydrogen atoms in thiol groups contained in the adhesive. For example, it is the value obtained by multiplying the number of active hydrogen atoms per unit amount (mol / g) of thiol in the adhesive by the thiol content. However, when two or more thiols are contained, the value is the sum of the values ​​obtained by multiplying the number of active hydrogen atoms per unit amount (mol / g) of each thiol by the content of each thiol. The number of active hydrogen atoms in thiol groups is defined as SHR (where R represents a functional group other than active hydrogen atoms, i.e., the portion of the thiol other than SH).

[0210] When both amine and thiol are contained, the number of active hydrogen atoms in the amino group and the thiol group is the total number of active hydrogen atoms in the amino group and the thiol group in the adhesive.

[0211] When a multifunctional acrylate compound is not used, the equivalent ratio is preferably adjusted as described above. When an epoxy-containing compound and a multifunctional acrylate compound are used in combination as the main agent, the contents of the epoxy-containing compound, the multifunctional acrylate compound and the amine in the adhesive are also preferably adjusted so that the equivalent ratio of the functional groups contained in each compound becomes as shown in the following formula (1).

[0212] [A / (B+C)] = 1.1 or more and 2.9 or less (1)

[0213] (It should be noted that in formula (1), A is the number of active hydrogen atoms in the amino group contained in the amine compound in the adhesive, B is the number of epoxy groups contained in the epoxy resin, and C is the number of (meth)acryloyl groups contained in the acrylate compound.)

[0214] When the equivalent ratio calculated from the above formula (1) is 1.2 or greater, the elastic modulus is easily reduced even when a low molecular weight adhesive component is used, making it easy to adjust the elastic modulus at 80°C to the specified range. In addition, when the equivalent ratio calculated from the above formula (1) is 2.9 or less, the elastic modulus is prevented from being excessively reduced beyond necessity, thereby preventing a decrease in adhesive strength, etc. The equivalent ratio calculated from the above formula (1) is more preferably 1.6 or greater, further preferably 2.0 or greater, more preferably 2.8 or less, and further preferably 2.7 or less.

[0215] It should be noted that the number of epoxy groups and the number of active hydrogen atoms in the above formula (1) are as described above. Furthermore, the number of (meth)acryloyl groups is the total amount of (meth)acryloyl groups contained in the adhesive, and is, for example, a value obtained by multiplying the number of (meth)acryloyl groups per unit amount (mol / g) of (meth)acryloyl groups contained in the adhesive by the content of the multifunctional acrylate compound. It should be noted that the number of (meth)acryloyl groups per unit amount (mol / g) of the multifunctional acrylate compound can be calculated, for example, from the functional group equivalent (g / eq).

[0216] The number of (meth)acryloyl groups can be measured using a mass spectrometer (GC-MS or LC-MS) in the same manner as the above-mentioned molecular weight, the number of epoxy groups, and the number of active hydrogen atoms.

[0217] The content of the binder in the adhesive is preferably 8% by volume or more and 65% by volume or less relative to the volume of the entire adhesive. If it is above the above lower limit, the thermally conductive filler can be appropriately dispersed in the thermally conductive component and the adhesive. In addition, the viscosity of the adhesive can be prevented from becoming higher than necessary. In addition, by being below the above upper limit, it is easy to make the adhesive contain a certain amount of thermally conductive filler. The content of the binder in the adhesive is more preferably 15% by volume or more and 55% by volume or less, and further preferably 18% by volume or more and 45% by volume or less.

[0218] [Thermal conductive filler]

[0219] The adhesive of the present invention contains a thermally conductive filler. When the adhesive contains a thermally conductive filler, the thermal conductivity of the thermally conductive member formed by the adhesive is improved.

[0220] Examples of the thermally conductive filler include metals, metal oxides, metal nitrides, metal hydroxides, carbon materials, oxides other than metals, nitrides, and carbides. Examples of the shape of the thermally conductive filler include spherical and irregular powders.

[0221] Among the thermally conductive filling materials, examples of metals include aluminum, copper, nickel, and the like. Examples of metal oxides include aluminum oxides, magnesium oxides, zinc oxides, and the like represented by aluminum oxide (alumina). Examples of metal nitrides include aluminum nitride and the like. Examples of metal hydroxides include aluminum hydroxide. Further, examples of carbon materials include spherical graphite and the like. Examples of oxides, nitrides, and carbides other than metals include quartz, boron nitride, and silicon carbide. Among these, aluminum oxides are preferred from the perspective of improving the heat dissipation of the thermally conductive member, and aluminum hydroxide is preferred when it is desired to improve flame retardancy.

[0222] As the thermally conductive filler, the above-mentioned substances may be used alone or in combination of two or more.

[0223] The average particle size of the thermally conductive filler is preferably 0.1 μm or more and 200 μm or less, more preferably 0.5 μm or more and 150 μm or less, and even more preferably 1 μm or more and 110 μm or less.

[0224] The thermally conductive filler preferably uses a small-particle thermally conductive filler with an average particle size of 0.1 μm to 5 μm and a large-particle thermally conductive filler with an average particle size of more than 5 μm to 200 μm. Using thermally conductive fillers with different average particle sizes can increase the filling rate.

[0225] The average particle size of the thermally conductive filler can be measured by observation using an electron microscope, etc. More specifically, the particle sizes of 50 arbitrary thermally conductive fillers can be measured using an electron microscope or an optical microscope, and the average value (arithmetic mean) can be defined as the average particle size.

[0226] The content of the thermally conductive filler in the adhesive is preferably 30% by volume or more and 90% by volume or less relative to the volume of the entire adhesive. If it is above the above lower limit, a certain thermal conductivity can be imparted to the adhesive. In addition, by making the content of the thermally conductive filler below the above upper limit, the thermally conductive filler can be properly dispersed in the thermally conductive component, and the viscosity of the adhesive can be prevented from becoming higher than necessary. It should be noted that in the present invention, it is easy to increase the content of the thermally conductive filler by lowering the viscosity of the adhesive. The content of the thermally conductive filler in the adhesive is more preferably 40% by volume or more and 80% by volume or less, and further preferably 50% by volume or more and 75% by volume or less.

[0227] The content of the thermally conductive filler in the adhesive, expressed in parts by mass, is preferably 150 parts by mass or more and 3000 parts by mass or less, more preferably 200 parts by mass or more and 2000 parts by mass or less, and even more preferably 300 parts by mass or more and 1000 parts by mass or less, relative to 100 parts by mass of the adhesive.

[0228] (Dispersant)

[0229] The adhesive of the present invention may also contain a dispersant. Examples of dispersants include polymeric dispersants. Examples of polymeric dispersants include polymer compounds having functional groups. Examples of polymer compounds include acrylic, vinyl, polyester, polyurethane, polyether, epoxy, polystyrene, amino, and silicone compounds. Functional groups include carboxyl, phosphoric, sulfonic, carboxylate, phosphate, sulfonate, hydroxy, amino, quaternary ammonium, and amide groups. Dispersants other than polymeric dispersants may be used, such as alkoxysilane compounds.

[0230] The content of the dispersant in the adhesive is preferably 0.1 to 10 parts by mass, more preferably 0.2 to 5 parts by mass, and even more preferably 0.4 to 3 parts by mass, relative to 100 parts by mass of the binder.

[0231] (Plasticizer)

[0232] The adhesive of the present invention may contain a plasticizer. By containing a plasticizer, the elongation of the adhesive is easily improved, and the viscosity is easily reduced, thereby improving workability and the like.

[0233] Specific examples of the plasticizer include organic ester plasticizers such as monobasic organic acid esters and polybasic organic acid esters, organic phosphoric acid plasticizers such as organic phosphoric acid plasticizers and organic phosphorous acid plasticizers, and epoxy plasticizers such as sulfonamides and epoxidized soybean oil. Preferably, the plasticizer is an organic ester plasticizer.

[0234] Examples of the monobasic organic acid esters include glycol esters obtained by reacting glycols with monobasic organic acids. Examples of the glycols include triethylene glycol, tetraethylene glycol, and tripropylene glycol. Examples of the monobasic organic acids include butyric acid, isobutyric acid, hexanoic acid, 2-ethylbutyric acid, heptanoic acid, n-octanoic acid, 2-ethylhexanoic acid, n-nonanoic acid, decanoic acid, and benzoic acid.

[0235] Examples of the polybasic organic acid esters include ester compounds formed between polybasic organic acids and linear or branched alcohols having 3 to 10 carbon atoms. Examples of the polybasic organic acids include adipic acid, sebacic acid, azelaic acid, and 1,2-cyclohexanedicarboxylic acid.

[0236] Examples of the organic ester plasticizer include triethylene glycol di-2-ethyl propionate, triethylene glycol di-2-ethyl butyrate, triethylene glycol di-2-ethyl hexanoate, triethylene glycol dioctanoate, triethylene glycol di-n-octanoate, triethylene glycol di-n-heptanoate, tetraethylene glycol di-n-heptanoate, dibutyl sebacate, dioctyl azelate, dibutyl carbitol adipate, ethylene glycol di-2-ethyl butyrate, 1,3-propylene glycol di-2-ethyl butyrate, 1,4-butylene glycol di-2-ethyl butyrate, diethylene glycol di-2-ethyl butyrate, and diethylene glycol di-2-ethyl butyrate. Ethylhexanoate, dipropylene glycol di-2-ethylbutyrate, triethylene glycol di-2-ethylvalerate, tetraethylene glycol di-2-ethylbutyrate, diethylene glycol dicaprylate, diethylene glycol dibenzoate, dipropylene glycol dibenzoate, diisononyl 1,2-cyclohexanedicarboxylate, dihexyl adipate, dioctyl adipate, hexylcyclohexyl adipate, a mixture of heptyl adipate and nonyl adipate, diisononyl adipate, diisodecyl adipate, heptylnonyl adipate, dibutyl sebacate, oil-modified sebacic acid, and a mixture of a phosphate and an adipate. Organic ester plasticizers other than these may also be used. Other adipic acid esters other than the above-mentioned adipic acid esters may also be used.

[0237] Examples of the organic phosphoric acid plasticizer include tributoxyethyl phosphate, isodecylphenyl phosphate, and triisopropyl phosphate.

[0238] The plasticizer is preferably a diester plasticizer represented by the following formula (1) or (2).

[0239]

[0240] In the above formula (1), R1 and R2 each represent an organic group having 2 to 10 carbon atoms, R3 represents an ethylene group, an isopropylene group, or an n-propylene group, and p represents an integer from 3 to 10. In the above formula (1), R1 and R2 each preferably represent an organic group having 5 to 10 carbon atoms, and more preferably represent an organic group having 6 to 10 carbon atoms.

[0241]

[0242] In the above formula (2), R4 and R5 each represent a hydrocarbon group having 3 to 10 carbon atoms, and R6 represents a hydrocarbon group having 2 to 10 carbon atoms. R4 and R5 in the above formula (2) each preferably have 4 to 9 carbon atoms, more preferably 6 to 9 carbon atoms. The hydrocarbon groups of R4 and R5 are preferably alkyl groups. The alkyl group may be a straight chain or a branched chain. R6 preferably has 4 to 9 carbon atoms, more preferably 5 to 8 carbon atoms. The hydrocarbon group of R6 is preferably an aliphatic hydrocarbon group, more preferably an unsaturated aliphatic hydrocarbon group. R6 may be a straight chain or a branched chain or a cyclic structure, but preferably has a cyclic structure.

[0243] The plasticizer preferably includes triethylene glycol di-2-ethylhexanoate (3GO), triethylene glycol di-2-ethylbutyrate (3GH), triethylene glycol di-2-ethylpropionate, or diisononyl-1,2-cyclohexanedicarboxylate (DINCH). The plasticizer more preferably includes triethylene glycol di-2-ethylhexanoate (3GO), triethylene glycol di-2-ethylbutyrate (3GH), or diisononyl-1,2-cyclohexanedicarboxylate (DINCH), and further preferably includes triethylene glycol di-2-ethylhexanoate.

[0244] From the viewpoint of reducing the viscosity of the first agent, the second agent, and the composition obtained by mixing them, the molecular weight of the plasticizer is preferably less than 1000, more preferably less than 500, and preferably 50 or more, more preferably 100 or more. Furthermore, the molecular weight of the plasticizer is preferably 50 or more and less than 1000, more preferably 100 or more and less than 500. The molecular weight of the plasticizer is the molecular weight calculated from the structural formula when the structural formula is known; if the structural formula is unclear, it can be measured using a mass spectrometer (GC-MS or LC-MS).

[0245] The content of the plasticizer in the adhesive is preferably 3% to 20% by mass, more preferably 5% to 15% by mass, and even more preferably 7% to 10% by mass, based on the total amount of the thermally conductive composition. If the amount of the plasticizer is above these lower limits, the viscosity of the composition can be reduced. If the amount of the plasticizer is below these upper limits, the reliability of the adhesive can be easily improved.

[0246] (Other additives)

[0247] The adhesive of the present invention may also contain additives other than those mentioned above. Examples of such additives include water that promotes the reaction between the main agent and the curing agent, curing catalysts such as bisphenol A, silanol condensation catalysts, reaction rate controllers (curing retarders) that inhibit the reaction between the main agent and the curing agent, thixotropy-imparting agents, flame retardants, antioxidants, colorants, dehydrating agents, adhesion promoters, and the like.

[0248] Furthermore, the adhesive of the present invention preferably does not contain a polyfunctional (meth)acrylate. By not containing a polyfunctional (meth)acrylate, it is possible to prevent the crosslinking density from increasing and to lower the elastic modulus at 80°C.

[0249] When a plasticizer is used, it is preferred to use a plasticizer having a high molecular weight, and it is more preferred to use a reactive plasticizer or a substantially non-volatile plasticizer.

[0250] Supply Form

[0251] The adhesive of the present invention may be in the form of a one-component type or a two-component type comprising a first component and a second component. However, from the viewpoint of storage stability, a two-component type is preferred.

[0252] In a two-component adhesive, the volume ratio of the first component to the second component (part 2 / part 1) is preferably 1 or a value close to 1. Specifically, it is preferably 0.9 or more and 1.1 or less, and more preferably 0.95 or more and 1.05 or less. By setting the volume ratio of the first component to the second component to 1 or a value close to 1, the preparation of the adhesive is facilitated.

[0253] Furthermore, in a two-component adhesive, it is preferred that both the first and second components be liquid at room temperature (25°C), and that the first and second components have the same viscosity, or, if different, a small difference in viscosity. By ensuring that the first and second components have the same or similar viscosities, uniform mixing of the adhesive is facilitated.

[0254] Specifically, the viscosity difference between the first and second agents (Pa·s) is preferably 150 Pa·s or less, more preferably 100 Pa·s or less, and even more preferably 50 Pa·s or less. The viscosity difference may be 0 Pa·s or more.

[0255] The viscosity of the first and second agents is not particularly limited, but is, for example, 10 Pa·s to 300 Pa·s, preferably 30 Pa·s to 250 Pa·s, and more preferably 40 Pa·s to 200 Pa·s.

[0256] It should be noted that the viscosity of the first and second agents can be measured using a rheometer (e.g., The sample temperature was adjusted to 25°C using a Peltier plate. A 25 mm φ parallel plate was used. The sample was placed and allowed to stand for 10 minutes. The viscosity was then measured while continuously varying the shear rate within the range of 0.0001 to 100 1 / sec. The viscosity values ​​listed above are those at a shear rate of 3.16 1 / sec.

[0257] More specifically, a two-component adhesive preferably comprises a first component containing a main adhesive component, and a second component containing a curing agent for the adhesive. The curing agent preferably cures upon mixing with the first component. The following detailed description of the composition of a two-component adhesive will typically describe an epoxy-based adhesive.

[0258] In a two-component adhesive, the first component preferably contains a base component (a compound containing an epoxy group in the case of an epoxy-based adhesive) but does not contain a curing agent (amine or thiol in the case of an epoxy-based adhesive). Furthermore, a curing catalyst may be contained as needed.

[0259] On the other hand, the second agent contains a curing agent (in the case of epoxy-based systems, amines and thiols). Furthermore, it is preferable that the second agent does not contain a curing catalyst, and furthermore, it is preferable that it does not contain a main agent (in the case of epoxy-based systems, a compound containing an epoxy group). However, the second agent may contain a main agent (in the case of epoxy-based systems, a compound containing an epoxy group) as long as it does not react with the curing agent. Furthermore, in the case of epoxy-based systems, when a multifunctional acrylate compound is used, it is preferable that the first agent contains the multifunctional acrylate compound and the second agent does not contain the multifunctional acrylate compound.

[0260] Furthermore, when the binder is an organic polymer having a hydrolyzable silyl group, it is preferred that the organic polymer having a hydrolyzable silyl group is contained in both the first part and the second part as described above. Furthermore, when the binder contains an organic polymer having a hydrolyzable silyl group, it is preferred that after a plasticizer is contained in both the first part and the second part as needed, at least one selected from a dehydrating agent, an adhesion promoter, and a silanol condensation catalyst is contained in the first part, and water is contained in the second part.

[0261] Furthermore, the thermally conductive filler is contained in at least one of the first agent and the second agent, but is preferably contained in both the first agent and the second agent.

[0262] Therefore, when the adhesive comprises a base and a curing agent, it is preferred that the first adhesive contain the base (in the case of an epoxy-based adhesive, a compound containing an epoxy group) and a thermally conductive filler, and the second adhesive contain the curing agent (in the case of an epoxy-based adhesive, at least one of an amine and a thiol) and a thermally conductive filler. Furthermore, it is even more preferred that the first adhesive contain no curing agent, and the second adhesive contain no base. Therefore, it is even more preferred that the entire base of the adhesive be contained in the first adhesive, and the entire curing agent be contained in the second adhesive.

[0263] Furthermore, the thermally conductive filler is preferably contained in both the first and second agents as described above, but more preferably is contained approximately equally in both. Specifically, the ratio (volume ratio) of the thermally conductive filler content in the second agent to the thermally conductive filler content in the first agent is preferably 0.67 to 1.5, more preferably 0.83 to 1.2, and even more preferably 0.91 to 1.1. By distributing the thermally conductive filler approximately equally between the first and second agents, the viscosity difference between the first and second agents can be minimized, and the volume ratio of the first to second agents can be close to 1.

[0264] Furthermore, the viscosity difference between the first and second agents can also be adjusted by adjusting the viscosity of the epoxy compound, amine, or thiol used. Specifically, to reduce the viscosity of the first agent containing an epoxy compound, a low-viscosity epoxy compound can be used or its content can be increased. Furthermore, the viscosity can be adjusted to a lower value by adding a dispersant or plasticizer.

[0265] Furthermore, in order to adjust the range of the equivalent ratio of the number of epoxy groups and active hydrogen and adjust the viscosity difference and volume ratio between the first and second agents, it is preferable to adjust the content of the thermally conductive filler and the amount of the plasticizer having no active hydrogen.

[0266] In the case of a combination in which the first agent contains an epoxy-containing compound as a main component and the second agent contains at least one of an amine and a thiol as a main component, there may be a density difference between the first and second agents. When the densities of the first and second agents are similar, mixing is sometimes facilitated, and a smaller density difference is preferred. Specifically, the ratio of the density of the first agent to the density of the second agent (also referred to as the density ratio) is preferably 0.7 to 1.4, more preferably 0.8 to 1.2, and even more preferably 0.9 to 1.1.

[0267] In order to reduce the density ratio, the contents of the thermally conductive filler in the first and second agents may be adjusted within the above-mentioned range.

[0268] It should be noted that the phrase "the first agent contains an epoxy-containing compound as a main component" means that the epoxy-containing compound contained in the curable thermally conductive adhesive accounts for more than 50% by mass of the epoxy-containing compound. Furthermore, the phrase "the second agent contains at least one of an amine and a thiol as a main component" means that the amine and thiol contained in the curable thermally conductive adhesive account for more than 50% by mass of the amine and thiol contained in the curable thermally conductive adhesive.

[0269] In a two-component type, a dispersant and other additives may be contained in one or both of the first and second components as needed. For example, if a thermally conductive filler is contained in both the first and second components, the dispersant may be contained in both components.

[0270] In two-component adhesives, the ratio of the functional group concentration (mol / g) of the second component to the functional group concentration (mol / g) of the first component is preferably 1.2 or greater and 2.9 or less. By keeping the functional group concentrations of the first and second components within this range, when the first and second components are mixed at a volume ratio of 1:1, the main component and curing agent react at an appropriate equivalent ratio, allowing the adhesive to cure while maintaining appropriate bond strength without excessively dense three-dimensional crosslinks or increasing the elastic modulus.

[0271] The functional group concentration ratio is more preferably 1.6 or more, and even more preferably 2.0 or more, and is more preferably 2.8 or less, and even more preferably 2.7 or less.

[0272] It should be noted that the term "functional group concentration" refers to the concentration of functional groups contained in the main agent or curing agent that are reactive with the curing agent or main agent. For compounds containing epoxy groups, the epoxy groups serve as functional groups, and the number of epoxy groups per unit weight (g) serves as the functional group concentration. Furthermore, for amines and thiols, the active hydrogen serves as the functional group, and the number of active hydrogens per unit weight (g) serves as the functional group concentration.

[0273] For example, in a preferred embodiment, the first agent contains an epoxy-containing compound but does not contain an amine or a thiol, and the second agent contains either an amine or a thiol but does not contain an epoxy-containing compound. In this case, the concentration of epoxy groups in the first agent becomes the functional group concentration of the first agent, and the concentration of active hydrogen of amines and thiols in the second agent becomes the functional group concentration of the second agent.

[0274] In the case of a two-component adhesive, the first and second components are preferably filled into separate containers. Specifically, the first component is preferably filled into the first container, and the second component is preferably filled into the second container. The first and second containers may be separate or integrated. By integrating the first and second containers, it is easier to supply them to the customer as a container kit. It should be noted that in this specification, the first container filled with the first component and the second container filled with the second component are sometimes collectively referred to as a container kit.

[0275] As the container, a syringe, a box, a barrel, a drum, etc. can be cited, but it is not limited to these. For example, when it is filled in a syringe, a two-liquid parallel type syringe is preferably used. Figure 1 As shown, the two-liquid parallel syringe 30 is a first syringe 31 constituting a first container and a second syringe 32 constituting a second container, arranged side by side and integrated. The first agent 35 and the second agent 36 filled in the syringes 31 and 32 are preferably mixed by being discharged from the syringes using the syringes as distributors.

[0276] In addition, when using a cartridge, the container set is composed of a first cartridge constituting the first container and a second cartridge constituting the second container, and these cartridges may be integrated. It should be noted that the cartridge is typically placed in a syringe (e.g., a first syringe, a second syringe), and the first dose delivered from the first cartridge and the second dose delivered from the second cartridge are preferably mixed by being discharged from the respective discharge ports of the first and second syringes using the respective syringes as dispensers.

[0277] The first and second agents are preferably mixed using a static mixer or other mixer. Figure 1 As shown, the static mixer 38 is connected to the discharge port 31A of the first syringe 31 and the discharge port 32A of the second syringe 32, so that the first agent 35 and the second agent 36 discharged from the discharge ports 31A and 32A can be mixed inside the mixer 38. The mixture (adhesive) obtained by mixing in the mixer 38 is preferably discharged from the discharge port 39 of the mixer 38.

[0278] Each syringe 31, 32 preferably has a structure in which the openings of the cylinders 33A, 34A into which the first dose 35 and the second dose 36 are respectively filled are closed by the caps 33B, 34B. Figure 1 In the illustrated syringe 30 , the first dose 35 and the second dose 36 are squeezed out by removing the caps 33B and 34B and inserting pistons (not shown) from the openings, and are preferably discharged from the discharge ports 31A and 32A.

[0279] In addition, in the case of using drums and cans, the container kit is as follows Figure 2 As shown, it is preferable to include a first can 41 that constitutes a first container and is filled with a first agent 45, and a second can 42 that constitutes a second container and is filled with a second agent 46. It should be noted that each can 41, 42 includes, for example, a container body 43A, 44A that is filled with the first agent 45 and the second agent 46 and has an opening, and a lid 43B, 44B that closes the opening of each container body 43A, 44A.

[0280] (Method for preparing adhesive)

[0281] When the adhesive of the present invention is a two-component adhesive, the first and second components are preferably obtained by mixing the components constituting the first and second components, respectively. Similarly, when the adhesive is a one-component adhesive, the components constituting the adhesive are preferably mixed. The method for mixing the components is not particularly limited; for example, the adhesive may be prepared by adding a thermally conductive filler, optionally mixed with an additive such as a dispersant, and then stirring or kneading the mixture.

[0282] Alternatively, the thermally conductive filler may be surface-treated with a dispersant before being mixed with the adhesive. The thermally conductive filler is surface-modified by pre-treating the surface with a dispersant. Furthermore, the pre-modified thermally conductive filler is preferably mixed with the adhesive to prepare an adhesive.

[0283] The method for pre-treating the surface with a dispersant is not particularly limited, and any known method may be used. Examples include wet treatment and dry treatment. For example, a wet treatment involves adding a thermally conductive filler to a treatment solution obtained by dispersing or dissolving a dispersant in a solvent, mixing the mixture, and then drying, heating, washing, or other methods to allow the dispersant to bind or adhere to the surface of the thermally conductive filler. Dry treatment involves surface treatment without the use of a dispersion medium. Specifically, a dispersant is mixed with the thermally conductive filler, stirred using a mixer, and then heated to allow the dispersant to bind or adhere to the surface of the thermally conductive filler.

[0284] [Thermal conductive components]

[0285] The adhesive of the present invention is preferably used as a thermally conductive component. The adhesive of the present invention becomes a thermally conductive component by curing. The thermally conductive component of the present invention comprises a polymer matrix and a thermally conductive filler. The polymer matrix is ​​formed by curing the adhesive, and the thermally conductive filler is dispersed and retained within the polymer matrix. Thus, for example, if the adhesive is epoxy-based, the polymer matrix is ​​composed of a cured epoxy resin.

[0286] It should be noted that the details of the thermally conductive filler in the thermally conductive filler are the same as those of the thermally conductive filler in the adhesive described above, and therefore, their description is omitted. Furthermore, the binder used to form the polymer matrix is ​​the same as those of the binder in the adhesive described above, and therefore, their description is omitted. The same applies to the dispersant and other additives.

[0287] The above description of the binder content and the thermally conductive filler content is based on the volume of the entire adhesive. Since the thermally conductive component is formed of the adhesive, the volume-based content of the adhesive described above can be regarded as the volume-based content of the thermally conductive component.

[0288] The thermal conductive member of the present invention has a mass reduction rate of 1.5% or less after a thermal cycle test at -40°C for 3 hours and 80°C for 3 hours, and an elastic modulus of 1.2×10 8 Pa or less. The thermally conductive member of the present invention has the above-mentioned configuration, thereby ensuring low viscosity, high thermal conductivity, and high adhesiveness, while also achieving high reliability.

[0289] Note that the suitable numerical ranges for the mass reduction rate after the thermal cycling test and the elastic modulus at 80°C of the thermally conductive member are the same as those for the cured adhesive, and therefore, description thereof will be omitted. The elastic modulus at 25°C and -40°C, the glass transition temperature, and the thermal conductivity of the thermally conductive member are also the same as those for the cured adhesive, and therefore, description thereof will be omitted.

[0290] The mass reduction rate, elastic modulus, glass transition temperature, and thermal conductivity of the thermally conductive member after the thermal cycling test were measured in the same manner as for the cured adhesive, except that the test sample was taken from the thermally conductive member.

[0291] [use]

[0292] The adhesive and thermally conductive member of the present invention can be used for various applications, for example, in battery assemblies such as lithium-ion batteries (LiB) assemblies, power electronic equipment, electronic packaging, LEDs, solar cells, power grids and other electronic equipment applications. Among them, they are preferably used in battery assemblies, and more preferably used in LiB assemblies. Therefore, in a preferred embodiment of the present invention, a battery assembly having the above-mentioned thermally conductive member is provided. It should be noted that battery assemblies such as LiB assemblies can be preferably used for automobiles.

[0293] In battery assembly applications, the adhesive and thermally conductive member of the present invention are preferably used as gap fillers within the battery assembly. Furthermore, in one embodiment, the adhesive and thermally conductive member of the present invention are preferably used in battery modules, and more preferably as gap fillers within battery modules. The following describes an example of the thermally conductive member of the present invention being used in a battery module.

[0294] The battery module comprises a gap material made of a thermally conductive component, multiple battery cells, and a module housing that houses the multiple battery cells. The gap material is located within the module housing. The gap material, made of a thermally conductive component, is filled between the battery cells and between the battery cells and the module housing. The filled gap material adheres tightly to the battery cells and the module housing. Thus, the gap material between the battery cells maintains the separation of the battery cells. Furthermore, the gap material between the battery cells and the module housing adheres tightly to both the battery cells and the module housing, transferring heat generated by the battery cells to the module housing.

[0295] Figure 3 Displays the specific structure of the battery module. Figure 4 Displays the specific structure of each battery unit. Figure 3As shown in FIG, a plurality of battery cells 11 are arranged inside the battery module 10. Each battery cell 11 is laminated and sealed in a flexible outer film, and the overall shape is a flat body with a thickness that is thin compared to the height and width. Figure 4 As shown in FIG, the positive electrode 11a and the negative electrode 11b are exposed to the outside, and the center portion 11c of the flat surface is formed to be thicker than the end portion 11d to be pressed.

[0296] like Figure 3 As shown in FIG. 1 , each battery cell 11 is arranged so that its flat surfaces face each other. Figure 3 In the configuration, gap material 13 is not filled to cover the entirety of the plurality of battery cells 11 housed within module housing 12. Instead, gap material 13 is filled to fill a portion (the bottom portion) of the gap within module housing 12. Gap material 13 is filled between battery cells 11 and between battery cells 11 and module housing 12, adhering closely to the surfaces of the battery cells 11 and the inner surface of module housing 12 in these portions.

[0297] The gap material 13 filled between the battery cells 11 adheres to the surfaces of the two battery cells 11. However, due to the appropriate elasticity and flexibility of the gap material 13 itself, even if an external force is applied that displaces the spacing between the battery cells 11, the strain caused by the external force can be alleviated. Therefore, the gap material 13 has the function of maintaining the separation between the battery cells 11.

[0298] The gap material 13 filling the gap between the battery cell 11 and the inner surface of the module case 12 is also tightly bonded to the surface of the battery cell 11 and the inner surface of the module case 12. As a result, heat generated inside the battery cell 11 is transferred through the gap material 13 bonded to the surface of the battery cell 11 to the inner surface of the module case 12, which is tightly bonded to the other surface of the gap material 13.

[0299] The gap material 13 is preferably formed within the battery module 10 by applying a liquid adhesive using a conventional dispenser and then curing the liquid adhesive. Furthermore, since the adhesive of the present invention has a low viscosity as described above, workability during the formation of the gap material 13 is improved. Furthermore, the gap material 13 is highly reliable, and its high thermal conductivity can be maintained over a long period of time.

[0300] When forming the gap material 13, a two-component adhesive is preferably used, as described above. A two-component adhesive is easy to store, and if mixed immediately before use, it is less likely to solidify during application with a dispenser, allowing for rapid curing after application. Application with a dispenser is also preferred because it allows the liquid adhesive to fill a relatively deep depth within the battery module 10 casing 12.

[0301] The gap material 13 covering the battery cells 11 preferably covers 20 to 40% of each battery cell 11 on one side of the battery cell 11. By being 20% ​​or more, the battery cell 11 can be stably held. In addition, by sufficiently covering the battery cells that generate a large amount of heat, the heat dissipation efficiency becomes good. On the other hand, by being 40% or less, the heat generated from the battery cells 11 can be efficiently dissipated, and an increase in weight and deterioration in workability can be prevented. In addition, in order to achieve good heat dissipation efficiency, it is preferred to cover the side of the battery cell 11 where the electrodes 11a and 11b are located with the gap material 13, and it is more preferred to cover the entire electrodes 11a and 11b with the gap material 13. As described above, the battery module 10 can release the heat generated from the battery cell 11 to the module case 12 via the gap material 13.

[0302] The gap material 13 is also preferably used in battery packs that include multiple battery modules 10. A battery pack generally includes multiple battery modules 10 and a battery pack housing that houses these modules 10. In such a battery pack, the gap material 13 can be provided between the battery modules 10 and the battery pack housing. This allows the heat released into the module housing 12, as described above, to be further dissipated into the battery pack housing, enabling effective heat dissipation.

[0303] In addition, in the above description, examples of battery assemblies being battery modules and battery packs having battery modules are described, but the present invention can also be applied to battery assemblies not having battery modules, for example, and is preferably applied to battery assemblies having a cell-to-battery pack structure.

[0304] A schematic diagram of a battery assembly having a cell to battery pack structure is shown in Figure 3In. The battery assembly 20 having a cell-to-battery pack structure includes a plurality of battery cells 21 and a battery pack shell, and the plurality of battery cells 21 are bonded to a base member 25 constituting the shell of the battery pack via a gap material 23 composed of a thermally conductive member (a cured adhesive). The base member 25 may constitute a cooling plate, etc. The adhesive of the present invention has high thermal conductivity and bonding strength. Therefore, the gap material 23 composed of the cured adhesive can bond the battery cell 21 to the base member 25 with a high bonding force, while effectively releasing the heat generated by the battery cell 21 to the base member 25. In addition, since the cured adhesive has high reliability, the high thermal conductivity of the gap material 23 can be maintained for a long time. It should be noted that the formation of the gap material 23 in the battery assembly 20 is preferably carried out in the same manner as the formation of the gap material 13 in the above-mentioned battery module, for example, it can be carried out using a general dispenser. Since the adhesive of the present invention has a low viscosity, the workability when forming the gap material 23 is also improved.

[0305] Example

[0306] Hereinafter, the present invention will be described in further detail with reference to Examples, but the present invention is not limited to these Examples.

[0307] [Elastic modulus]

[0308] The elastic modulus of the cured product of the adhesive is measured by the following method. The adhesive is applied to the surface of a 20 cm × 20 cm silicone release-treated PET film using an applicator in such a manner that the thickness after curing becomes 1 mm. The adhesive applied to the silicone release-treated PET film is then placed in an environment of 25°C and 50% RH for 168 hours to cure. The silicone release-treated PET film is then peeled off, and a test sample (cured product) of 30 mm × 5 mm and 1 mm in thickness is cut out from the obtained cured product. The obtained test sample is subjected to a forced vibration type dynamic viscoelasticity measuring apparatus ( The elastic modulus E' at -40°C, 25°C, and 80°C was measured under tension at a frequency of 10 Hz, a strain of 0.01%, a temperature range of -40°C to 100°C, and a heating rate of 5°C / min. The measured values ​​of the storage modulus E' at -40°C, 25°C, and 80°C were defined as the elastic modulus at -40°C, the elastic modulus at 25°C, and the elastic modulus at 80°C, respectively.

[0309] [Mass reduction rate after thermal cycling test (%)]

[0310] The mass reduction rate (%) of the cured adhesive after the hot and cold cycle test was determined by the following method. Use an applicator to apply the adhesive to the surface of a 20cm×20cm silicone release-treated PET film in such a way that the thickness after curing becomes 1mm. Then, the adhesive applied to the silicone release-treated PET film was placed in an environment of 25°C and 50% RH for 168 hours to cure it, and then the silicone release-treated PET film was peeled off to obtain a test sample (cured product) of 20mm×20mm and 1mm thickness. The obtained test sample was subjected to 20 cycles of hot and cold cycle tests at -40°C and 80°C (3 hours each, with both the heating time and the cooling time being 1 minute). The mass of the test sample before and after the hot and cold cycle test was measured, and the mass reduction rate was calculated using the following formula.

[0311] Mass reduction rate (%) = (1-(mass of the test sample after the hot and cold cycle test / mass of the test sample after the hot and cold cycle test)) × 100

[0312] [Glass transition temperature]

[0313] The glass transition temperature of the cured product of the adhesive was measured by the same method as the elastic modulus described above, and the temperature at which tan δ showed a maximum was defined as the glass transition temperature.

[0314] [Adhesion test]

[0315] The adhesive strength of the cured adhesive at 25°C was measured by the following method. First, two PET plates (trade name "PET-6010" with a width of 25 mm, a length of 100 mm, and a thickness of 2 mm) were prepared. Company). Furthermore, the adhesive is applied to the longitudinal end of one plate in a length of 5 mm over the entire width of the plate in such a way that the thickness after curing becomes 1 mm. Then, the longitudinal end of another plate is overlapped on the applied adhesive, and the plate is placed in this state under a 25°C, 50% RH environment for 168 hours to cure the adhesive and obtain a measurement sample. The measurement sample is formed by two PET plates overlapping in width with a length of only 5 mm, and the films are bonded to each other via a cured product of the adhesive (size: 25 mm × 5 mm, thickness 1 mm) at the overlapping portion, and has a size of 25 mm in width and 195 mm in length. The obtained measurement sample is subjected to a tensile test in an environment of 25°C, 50% RH, at a tensile speed of 10 mm / second along the longitudinal direction of the measurement sample until it breaks, and the maximum load is set as the bonding strength. In addition, the elongation value under the maximum load is set as the elongation under the maximum load. The failure mode at the time of fracture is also observed, and the cohesive failure is recorded as "G" and the interface failure is recorded as "K" in Tables 1 and 2.

[0316] [Thermal conductivity]

[0317] The thermal conductivity of the first and second adhesives was measured using a thermal diffusivity / thermal conductivity measuring device ("ai-PhaseMobile M3", The thermal conductivity of each sample was measured using a 1mm thick aluminum plate. Specifically, 2 ml of adhesive was applied to an aluminum plate with a thickness of 1 mm, and then the plate was sandwiched with a glass plate with a thickness of 1 mm so that the thickness became 1 mm. The plate was cured at 18°C ​​for 18 hours to obtain each test sample. Furthermore, the obtained test sample was subjected to 20 cycles of hot and cold cycle tests at -40°C and 80°C (3 hours each, with a heating time and a cooling time of 1 minute each). The test samples before and after the hot and cold cycle tests were scanned in the range of 0.1 to 1.0 Hz to obtain the thermal diffusivity. This measurement was performed on 20 different locations in the test sample. Then, the thermal conductivity was calculated by multiplying the measured thermal diffusivity by the specific heat and density. It should be noted that the thermal conductivity was set as the average value of 20 locations, and the standard deviation was also calculated. Furthermore, the thermal conductivity and standard deviation obtained by the above method were evaluated using the following benchmarks.

[0318] A: Thermal conductivity is 1.5 W / m·K or higher, and the standard deviation is 0.2 W / m·K or lower.

[0319] B: Thermal conductivity is 0.7 W / m·K or more and less than 1.5 W / m·K, and the standard deviation is 0.25 W / m·K or less.

[0320] C: Thermal conductivity is less than 0.7 W / m·K, or the standard deviation exceeds 0.25 W / m·K.

[0321] [Viscosity]

[0322] A sample of the adhesive immediately after preparation (immediately after mixing the first and second agents) was subjected to a rheometer (e.g. The sample temperature was adjusted to 25°C using a Peltier plate and a 25 mm φ parallel plate. The sample was immediately placed and the shear rate was continuously varied within a range of 0.0001 to 100 1 / s. The viscosity was measured at a shear rate of 3.16 1 / s. The viscosity of the first and second components before mixing was similarly measured after the samples were placed and allowed to stand for 10 minutes.

[0323] <Evaluation>

[0324] [Hot and cold cycle test]

[0325] 6.5 to 7.0 ml of adhesive was applied to the center of a 1 mm thick, 10 cm x 10 cm aluminum plate, preventing the introduction of air bubbles. 2 mm spacer rings were then placed at the four corners of the aluminum plate. Next, a glass plate (2 mm thick, 10 cm x 10 cm) was placed on the coated sample, pressing the applied adhesive onto the aluminum plate so that it just overlapped the plate. The spacer rings were then secured with clips at four locations on the top.

[0326] The resulting structure was left at 25°C and 50% RH for 168 hours to cure the adhesive, yielding a test sample in which an aluminum plate and a glass plate were bonded together via a 2mm thick cured adhesive. The resulting test sample was subjected to 20 cycles of -40°C and 80°C hot and cold cycling tests (3 hours each, with both a 1-minute heating and cooling time). The condition of the test sample at this point was evaluated using the following criteria.

[0327] [Judgment Criteria]

[0328] A: No peeling or volatilization marks

[0329] B: There is slight peeling of 10% or less of the total area, or there are less than 10 volatilization marks.

[0330] C: Exfoliation exceeding 10% of the total area, or 11 or more volatilization marks.

[0331] [Examples 1 to 15, Comparative Examples 1 to 3]

[0332] The components were mixed according to the formulations in Tables 1 and 2 to prepare the first and second agents. 50cc of each of the first and second agents were placed in a two-part parallel cartridge and mixed at a volume ratio of 1:1 using a static mixer at room temperature to obtain an adhesive. The physical properties of the resulting adhesive were determined, and evaluation tests were also conducted.

[0333] The components used in the examples and comparative examples are as follows.

[0334] (Compounds containing epoxy groups)

[0335] Resorcinol type epoxy resin (trade name "EX-201", Company), molecular weight 222, viscosity (25°C) 250 mPa·s (catalog value), epoxy equivalent 117 g / eq, number of functional groups 2, specific gravity 1.23

[0336] Phenyl glycidyl ether (trade name " EX141", Produced by a company, molecular weight 150, viscosity (25°C) 8 mPa·s (catalog value), epoxy equivalent 151 g / eq, number of functional groups 1, specific gravity 1.11, CAS No. 122-60-1

[0337] Multifunctional epoxy resin: bisphenol F epoxy resin (trade name "jER806", Company), molecular weight 330, epoxy equivalent 165g / eq, number of functional groups 2, viscosity (25°C) 2000mPa·s

[0338] Trimethylolpropane polyglycidyl ether (trade name "EX321", Company), molecular weight 280, viscosity (25°C) 130 Pa·s, epoxy equivalent 140 g / eq, number of functional groups 2

[0339] p-tert-Butylphenyl glycidyl ether (trade name "EX146", Company), molecular weight 206, viscosity (25°C) 20 mPa·s, epoxy equivalent 255 g / eq, number of functional groups 1

[0340] (Curing agent: amine)

[0341] Trimethylolpropane poly(oxypropylene)triamine (trade name "T-403", manufactured by HUNTSMAN), molecular weight 440, viscosity (25°C) 7.0 Pa·s, active hydrogen equivalent 73.3 g / eq, amine value 291 mgKOH, functional group = 3×(-NH2), specific gravity 0.978, CAS No. 39423-51-3

[0342] Poly(oxypropylene)diamine (trade name "D-400", manufactured by HUNTSMAN), molecular weight 430, viscosity 250 mPa·s, active hydrogen equivalent 105 g / eq, number of functional groups 2 (-NH2) × 2)

[0343] Phenalkamine (trade name "NC-540", manufactured by Cardolite), viscosity 2.5 Pa·s, active hydrogen equivalent 81 g / eq, amine value 490-550 mgKOH, specific gravity 0.99

[0344] m-Xylylenediamine, molecular weight 136, viscosity (25°C) 6.8 mPa·s, active hydrogen equivalent 34 g / eq, amine value 824 mgKOH, functional group = 2×(-NH2), specific gravity 1.05, CAS No. 1477-55-0

[0345] 1:1 reaction product of m-xylenediamine and styrene (trade name "GASKAMINE240", Company), molecular weight 240, viscosity (25°C) 6.6 mPa·s, active hydrogen equivalent 80 g / eq, amine value 403 mgKOH, functional groups = 1×(-NH2) and 1×(-NH-), specific gravity 1.05

[0346] Amidoamine (trade name "PAS151", manufactured by Ohtake Meishin Chemical Co., Ltd.), molecular weight 368, viscosity (25°C) 300 mPa·s, active hydrogen equivalent 92 g / eq, amine value 400 mgKOH, functional group = 1×(-NH2) + 2×(-NH), specific gravity 0.95

[0347] (Acrylic monomer)

[0348] Pentaerythritol alkoxy tetraacrylate (trade name "EBECRYL 40", Company), molecular weight 571, viscosity 160mPa·s, acrylic acid equivalent 145g / eq, number of functional groups 4

[0349] Dipentaerythritol hexaacrylate (trade name "DPHA", Company), molecular weight 520, viscosity 6.9 Pa·s, acrylic acid equivalent 86 g / eq, number of functional groups 6

[0350] (Carbamate)

[0351] Polytetramethylene ether glycol (trade name "PTMG1000", Company), molecular weight 1000, viscosity 320mPa·s (40℃)

[0352] 1,6-hexamethylene diisocyanate (trade name " TLA100", manufactured by Asahi Kasei Co., Ltd.), molecular weight 100, viscosity 500mPa·s (25℃)

[0353] <Organic polymer having a hydrolyzable silyl group>

[0354] Company-made "MS SAT350", number average molecular weight 12,500, linear type, terminal silylation rate 91%, organic polymer with dimethoxymethylsilyl groups at both ends of polyoxypropylene

[0355] (Plasticizer)

[0356] Triethylene glycol di(2-ethylhexanoate) 3GO

[0357] (Dispersant)

[0358] Polymer dispersants (copolymers containing acidic groups)

[0359] <Additives>

[0360] Silanol condensation catalyst: dibutyltin dilaurate

[0361] water

[0362] Dehydrating agent: vinyltrimethoxysilane

[0363] Adhesion promoter: N-(2-aminoethyl)-3-aminopropyltrimethoxysilane

[0364] Dispersants: Socially produced "DISPERBYK-106"

[0365] (Thermal conductive filling material)

[0366] Aluminum hydroxide 1: amorphous, average particle size 1μm

[0367] Aluminum hydroxide 2: amorphous, average particle size 10μm

[0368] Aluminum hydroxide 3: amorphous, average particle size 105μm

[0369] Aluminum hydroxide 4: amorphous, average particle size 43μm

[0370] Aluminum oxide: spherical, average particle size 45μm

[0371] [Table 1]

[0372]

[0373] [Table 2]

[0374]

[0375] * The functional group content is the number of epoxy groups, the number of acryloyl groups, and the number of active hydrogen atoms in amino groups contained in amines per unit amount (g) of the epoxy-containing compound.

[0376] * The equivalent ratio is the ratio of the number of active hydrogen atoms in the amino group contained in the amine to the total number of epoxy groups in the epoxy-containing compound and the number of acryloyl groups in the acrylic monomer in the adhesive obtained by mixing the first and second parts at a volume ratio of 1:1.

[0377] The adhesives of the above embodiments have a mass reduction rate of less than 1.5% after the thermal cycle test of the cured product, and an elastic modulus of 1.2×10 8Pa or less, thus ensuring low viscosity, high thermal conductivity, and high adhesion, and at the same time, no failure occurred during the thermal cycle test, resulting in high reliability. In contrast, the adhesives of the comparative examples had a mass reduction rate of more than 1.5% after the thermal cycle test of the cured product, or an elastic modulus of more than 1.2×10 8 Pa, so malfunctions occurred during the thermal cycle test and reliability was insufficient.

[0378] Explanation of symbols

[0379] 10 battery modules

[0380] 11, 21 battery cells

[0381] 12 Battery module housing (module housing)

[0382] 13, 23 gap material

[0383] 20 battery packs

[0384] 25 Basic Components

[0385] 30 syringes

[0386] 31 First syringe

[0387] 31A Discharge port of the first syringe

[0388] 32 Second syringe

[0389] 32A Discharge port of the second syringe

[0390] 33A, 34A tube

[0391] 33B, 34B cylinder cover

[0392] 35, 45 1st dose

[0393] 36, 46 2nd dose

[0394] 38 Mixer

[0395] 39 Mixer outlet

[0396] 41 The first barrel

[0397] 42 The second barrel

[0398] 43A, 44A Container body with opening

[0399] 43B and 44B are lids for closing the opening of the container body.

Claims

1. A curable thermally conductive adhesive comprising a curable binder and a thermally conductive filler. The cured thermally conductive adhesive has a mass reduction rate of 1.5% or less after being subjected to 20 repeated hot and cold cycle tests at -40°C for 3 hours and 80°C for 3 hours, and an elastic modulus of 1.2×10 8 Below Pa.

2. The curable thermally conductive adhesive according to claim 1, wherein the elastic modulus is 3.0×10 6 Pa or above. 3 . The curable thermally conductive adhesive according to claim 1 , wherein the shear rate measured by a rheometer is 3.16 and the viscosity at 25° C. is 300 Pa·s or less, wherein the unit of the shear rate is 1 / s. The curable thermally conductive adhesive according to claim 1 , wherein the binder comprises an epoxy group-containing compound. The curable thermally conductive adhesive according to claim 1 , wherein the binder comprises at least one of an amine and a thiol. The curable thermally conductive adhesive according to claim 1 , wherein the binder comprises an epoxy group-containing compound and an amine. 7 . The curable thermally conductive adhesive according to claim 6 , wherein the equivalent ratio of the number of active hydrogen atoms in the amino group contained in the amine to the number of epoxy groups in the epoxy-containing compound (number of amino groups / number of epoxy groups) is 1.2 to 2.

9.

8. The curable thermally conductive adhesive according to claim 1, comprising a first component and a second component, wherein the first component contains a main component of the adhesive and is filled in a first container, and the second component contains a curing agent that cures by mixing with the first component and is filled in a second container. 9 . The curable thermally conductive adhesive according to claim 8 , wherein a difference between the viscosity of the first agent and the viscosity of the second agent is 150 Pa·s or less, and the unit of the viscosity is Pa·s. 10 . The curable thermally conductive adhesive according to claim 8 , wherein a ratio of a functional group concentration of the second agent to a functional group concentration of the first agent is 1.2 to 2.9, and a unit of the functional group concentration is mol / g. 11 . A container kit filled with the curable thermally conductive adhesive according to claim 8 , comprising a first container filled with the first agent and a second container filled with the second agent.

12. A thermally conductive component comprising a polymer matrix and a thermally conductive filler material, The thermal conductive member has a mass reduction rate of 1.5% or less after a thermal cycle test at -40°C for 3 hours and 80°C for 3 hours, and an elastic modulus of 1.2×10 8 Below Pa. 13 . A thermally conductive member made of a cured product of the curable thermally conductive adhesive according to claim 1 . 14 . A battery module comprising the thermally conductive member according to claim 12 .

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