High-temperature-resistant silane coupling agent, preparation method and application thereof

Abstract

The application provides a high-temperature-resistant silane coupling agent and a preparation method and application thereof. The structure of the high-temperature-resistant silane coupling agent is as follows: the preparation method comprises the following steps: reacting ethyl trimethoxysilane with chlorine to obtain chloroethyl trimethoxysilane; and reacting a mixed reaction system containing the chloroethyl trimethoxysilane and an epoxy diformamide potassium salt to obtain the high-temperature-resistant silane coupling agent. The epoxy structure in the high-temperature-resistant silane coupling agent can reduce the activity rotation ability of a chain segment, increase the rigidity, have a high glass transition temperature, and endow the high-temperature-resistant silane coupling agent with good heat resistance and thermal stability. Moreover, the adhesion and cohesive strength of the silane coupling agent are improved. The high-temperature-resistant silane coupling agent is suitable for preparing a resin-based heat-conducting phase change material, has a high adhesion strength with raw materials in the heat-conducting phase change material, and the prepared resin-based heat-conducting phase change material has good toughness.

Description

Technical Field

[0001] The invention belongs to the technical field of high-temperature resistant silane coupling agents, and particularly relates to a high-temperature resistant silane coupling agent, a preparation method thereof, and an application thereof. Background Art

[0002] Phase change heat storage has the advantages of stability, high efficiency and low price. It is a new type of green and efficient energy management method. In recent years, phase change materials have been widely used in the field of thermal management. Thermal conductive phase change material is a substance with high melting heat. It can melt or solidify under specific temperature conditions, store and release a large amount of energy, and realize the mutual transformation between solid and liquid. Unlike traditional heat-sensitive storage materials, when thermal conductive phase change materials reach their phase change temperature (melting point), they absorb a large amount of heat at an almost constant temperature, and continue to absorb heat until all the material is converted to liquid, and the temperature does not rise significantly. When the ambient temperature around the liquid material drops, it quickly solidifies again, releasing its stored latent heat.

[0003] Resin-based phase change composites (PCCs) are obtained by encapsulating a phase change material with a resin. For example, a composite network structure in high-density polyethylene (HDPE) or styrene-butadiene-styrene block copolymer (SBS) can be used to encapsulate the material. Resin-based PCCs exhibit excellent material coverage, mechanical strength, viscosity, and thermal conductivity. Silane coupling agents are typically used as thickeners for resin-based thermally conductive PCCs. Silane coupling agents function as thickeners because they can bond with thermally conductive fillers such as aluminum oxide, zinc oxide, and aluminum powder, as well as with resin polymers or adhesives, forming strong chemical bonds at the bonding interface and improving bond strength. Furthermore, in the production of PCCs, the addition of silane coupling agents can improve the dispersion and adhesion of thermally conductive fillers in the resin, while also enhancing the thermal conductivity of the material. However, during production, the melting temperature of the resin typically needs to be at least 130°C, at which point the silane coupling agent will significantly volatilize, thus affecting the thermal properties of the PCC. To improve the heat resistance of silane coupling agents, existing technologies have introduced heat-resistant aromatic structures into silane coupling agents, producing novel silane coupling agents containing aromatic groups. These agents exhibit an initial weight loss temperature exceeding 250°C and a 50% weight loss at approximately 400°C. However, these silane coupling agents are not suitable for use in resin-based phase change materials because aromatic coupling agents do not readily react with the resin, which can reduce the thermal properties of the resin-based phase change composites. They also reduce the viscosity of the composites and increase the dispersibility of thermally conductive fillers such as alumina, making it difficult for these fillers to enter the resin system, resulting in a decrease in thermal conductivity. Summary of the Invention

[0004] To solve all or part of the above technical problems, the present application provides the following technical solutions:

[0005] One of the purposes of the present application is to provide a high-temperature-resistant silane coupling agent, the structure of which is as follows:

[0006]

[0007] The epoxy structure in the high-temperature-resistant silane coupling agent of the structure shown reduces the active rotation ability of the chain segment, increases its rigidity, improves the glass transition temperature of the silane coupling agent, and the glass transition temperature can reach 230-260℃, giving it good heat resistance and thermal stability.

[0008] The second purpose of the present application is to provide a preparation method of a high-temperature-resistant silane coupling agent, which comprises:

[0009] reacting ethyl trimethoxysilane with chlorine to obtain chloroethyl trimethoxysilane;

[0010] reacting a mixed reaction system containing the chloroethyl trimethoxysilane and an epoxy dimethylamide potassium salt to obtain a high-temperature-resistant silane coupling agent.

[0011] In some embodiments, the mass ratio of the ethyl trimethoxysilane to chlorine is 82:34-82:68. The ethyl trimethoxysilane can be synthesized using trimethoxysilane, alpha-hexadecene, and a platinum catalyst as raw materials, or using commercially available ethyl trimethoxysilane, which is not particularly limited by the present application.

[0012] In some embodiments, the preparation method specifically comprises: providing a uniform first solution and a second solution containing chloroethyl trimethoxysilane, an epoxy dimethylamide potassium salt, and a solvent; heating the first solution to 60-85℃, and under the protection of an inert atmosphere, adding the second solution to the first solution in batches to obtain the mixed reaction system, and after the second solution is completely added, reacting at 65-100℃. Compared with the method of directly mixing all the raw materials for reaction, adding the second solution to the first solution in batches and then reacting can avoid a sharp rise in temperature due to the generation of a large amount of heat, which can reduce the yield.

[0013] In some embodiments, the mass ratio of chloroethyl trimethoxysilane to epoxy dimethylamide potassium salt in the first solution and the second solution is 60:78-60:156, and the first solution and the second solution are the same or different.

[0014] In some embodiments, the reaction is carried out at 65-100℃ for 10-13h.

[0015] In some embodiments, the solvent includes N,N-dimethylformamide, but is not limited thereto.

[0016] In some embodiments, the second solution is added at a drop rate of 30-45 drops / min.

[0017] In some embodiments, the preparation method of the potassium salt of epoxy diformamide includes: dissolving epoxy diformamide in ethanol to obtain an ethanol solution of epoxy diformamide, and heating the ethanol solution to 60-85° C.; then mixing the ethanol solution of epoxy diformamide with a potassium hydroxide solution, stirring, and rapidly cooling to room temperature to obtain a precipitate, which is the potassium salt of epoxy diformamide.

[0018] In some embodiments, the concentration of the ethanol solution of the potassium salt of epoxydicarbonamide is 78 g / mL to 156 g / mL, the concentration of the potassium hydroxide solution is 18 g / mL to 54 g / mL, and the volume ratio of the ethanol solution of the potassium salt of epoxydicarbonamide to the potassium hydroxide solution is 1:1 to 1:4.

[0019] A third object of the present invention is to provide a high temperature resistant silane coupling agent, which is prepared by any of the methods described above.

[0020] A fourth object of the present invention is to provide an application of the high-temperature resistant silane coupling agent in the preparation of a resin-based thermally conductive phase change material.

[0021] A fifth object of the present invention is to provide a resin-based thermally conductive phase change material. The raw materials of the resin-based thermally conductive phase change material include, by mass, 19.88 to 25.86 parts of resin, 74.14 to 80.12 parts of thermally conductive filler and 0.12 to 0.18 parts of coupling agent, wherein the coupling agent includes the high-temperature resistant silane coupling agent.

[0022] In some embodiments, the resin includes one or a combination of epoxy resin, rosin resin, and phenolic resin.

[0023] The thermally conductive filler may be a thermally conductive filler commonly used in the field of resin-based thermally conductive phase change materials, and the present invention does not impose any particular limitation thereto.

[0024] The high-temperature resistant silane coupling agent reacts with the resin and grafts into the resin's crosslinking system, improving its adhesion to the raw materials in the thermally conductive phase-change material. The resulting resin-based thermally conductive phase-change material has excellent toughness. During the reaction, the high-temperature resistant silane coupling agent undergoes hydrolysis, and the three SiOCH3 groups attached to the silicon atom hydrolyze to form SiOH. The three Si-OH groups then undergo dehydration and condensation to form a Si-OH-containing oligosiloxane. The SiOH groups in the oligosiloxane form hydrogen bonds with the resin backbone containing OH groups. During the heating process of the resin-based phase-change material, dehydration forms a covalent bond. The presence of the ring structure in the high-temperature resistant silane coupling agent also improves the stability of the material.

[0025] The sixth object of the present invention is to provide a method for preparing the resin-based thermally conductive phase change material, comprising: heating the raw materials to 150-180° C. and uniformly mixing them, forming them into a film, and obtaining a film-like resin-based thermally conductive phase change material.

[0026] Compared with the prior art, the present invention has at least the following advantages: the epoxy structure in the high-temperature resistant silane coupling agent provided by the present invention reduces the movable rotation ability of the chain links, increases their rigidity, and imparts a higher glass transition temperature, imparting good heat resistance and thermal stability, while also improving their adhesion and cohesive strength. The high-temperature resistant silane coupling agent reacts with the resin and grafts into the resin's crosslinking system, enhancing its adhesion to the raw materials in the thermally conductive phase change material. The resulting resin-based thermally conductive phase change material exhibits excellent thermal properties, electrical insulation stability, and toughness. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 This is the infrared spectrum of the high temperature resistant silane coupling agent prepared in Example 1. DETAILED DESCRIPTION

[0029] The technical solutions of the present invention are described in detail below in conjunction with specific embodiments so that those skilled in the art can better understand and implement the technical solutions of the present invention. The specific functional details disclosed herein should not be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching those skilled in the art to employ the present invention in various ways in virtually any appropriate detailed embodiment.

[0030] In addition, unless otherwise specified, the various raw materials used in the following examples can be purchased from the market and other channels, and the various production and testing equipment used are also equipment known in the art.

[0031] The present invention provides a high temperature resistant silane coupling agent. In some specific embodiments, the synthesis route of the high temperature resistant silane coupling agent is as follows:

[0032] Provided is a potassium salt of epoxydiformamide, which can be prepared by mixing an ethanol solution of epoxydiformamide with a potassium hydroxide solution and precipitating the mixture. The reaction process is as follows:

[0033]

[0034] Chloroethyltrimethoxysilane is provided. Chloroethyltrimethoxysilane can be obtained by reacting ethyltrimethoxysilane with chlorine. The reaction process is as follows:

[0035]

[0036] Chloroethyltrimethoxysilane and epoxydicarbonamide potassium salt are reacted to obtain a high temperature resistant silane coupling agent, and the reaction formula is as follows:

[0037]

[0038] The technical solution of the present invention is described in detail below in conjunction with specific implementation methods.

[0039] Example 1

[0040] This embodiment provides a high temperature resistant silane coupling agent and a preparation method thereof, which specifically includes the following steps:

[0041] Ethyltrimethoxysilane and chlorine gas were fully mixed in a mass ratio of 82:34 to react and obtain chloroethyltrimethoxysilane.

[0042] Heat 60g of epoxy diformamide and 52g of ethanol to boil to completely dissolve the solid to obtain epoxy diformamide solution. Prepare 61g of 18g / mL potassium hydroxide solution in a beaker. Pour epoxy diformamide at a temperature of 60°C into the potassium hydroxide solution, stir and quickly cool to room temperature. A large amount of precipitate is generated, which is filtered to obtain epoxy diformamide potassium salt.

[0043] The above-prepared chloroethyltrimethoxysilane and epoxydicarbonamide potassium salt were mixed in a mass ratio of 60:78, 40 mL of N,N-dimethylformamide (DMF) was added and heated to completely dissolve the chloroethyltrimethoxysilane and epoxydicarbonamide potassium salt to obtain a mixed solution; half of the mixed solution was added to a four-necked flask, and the mixture was stirred in an oil bath at 60°C under nitrogen protection to react, and the remaining half of the mixed solution was added to the four-necked flask by titration at a titration rate of 30 drops / min. After all the titration was completed, the mixture was kept at 65°C for 10 hours to obtain a high-temperature resistant silane coupling agent.

[0044] Figure 1 This is the infrared spectrum of the high temperature resistant silane coupling agent prepared in this embodiment. -1 The peak at is caused by the asymmetric stretching vibration of the CO bond, and the surface high-temperature resistant coupling agent contains epoxy dicarbonamide structure.

[0045] This embodiment also provides a resin-based phase change material using the silane coupling agent prepared above, as follows:

[0046] Calculated by mass, the raw materials of the resin-based phase change material include: 0.12 parts of the above-prepared high-temperature resistant silane coupling agent, 19.88 parts of bisphenol A epoxy resin and 74.14 parts of aluminum powder.

[0047] The above raw materials are evenly mixed, heated to 150°C, and stirred thoroughly to obtain a coating. The coating is evenly coated on a release film. After it is completely set, it is covered with a lighter release film to obtain a resin-based thermal conductive phase change material with a thickness of 0.2 mm.

[0048] Example 2

[0049] This embodiment provides a high temperature resistant silane coupling agent and a preparation method thereof, which specifically includes the following steps:

[0050] Ethyltrimethoxysilane and chlorine gas were fully mixed in a mass ratio of 82:51 to react and obtain chloroethyltrimethoxysilane.

[0051] Heat 60g of epoxy diformamide and 52g of ethanol to boil to completely dissolve the solid to obtain epoxy diformamide solution. Prepare 61g of 18g / mL potassium hydroxide solution in a beaker. Pour epoxy diformamide at 70°C into the potassium hydroxide solution, stir and quickly cool to room temperature. A large amount of precipitate is generated, which is filtered to obtain epoxy diformamide potassium salt.

[0052] The chloroethyltrimethoxysilane and epoxydicarbonamide potassium salt prepared above were mixed in a mass ratio of 60:117, 40 mL of N,N-dimethylformamide (DMF) was added and heated to completely dissolve the chloroethyltrimethoxysilane and epoxydicarbonamide potassium salt to obtain a mixed solution; half of the mixed solution was added to a four-necked flask, and the mixture was stirred in an oil bath at 60°C under nitrogen protection to react, and the remaining half of the mixed solution was added to the four-necked flask by titration at a titration rate of 40 drops / min. After all the titration was completed, the mixture was kept at 85°C for 12 hours to obtain a high-temperature resistant silane coupling agent.

[0053] The high temperature resistant silane coupling agent in the resin-based thermal conductive phase change material raw material of Example 1 was replaced with the high temperature resistant silane coupling agent prepared in this example, and a thin film resin-based thermal conductive phase change material was prepared according to the same method as Example 1.

[0054] Example 3

[0055] This embodiment provides a high temperature resistant silane coupling agent and a preparation method thereof, which specifically includes the following steps:

[0056] Ethyltrimethoxysilane and chlorine gas were fully mixed in a mass ratio of 82:68 to react and obtain chloroethyltrimethoxysilane.

[0057] Heat 60g of epoxy diformamide and 52g of ethanol to boil to completely dissolve the solid to obtain epoxy diformamide solution. Prepare 61g of 18g / mL potassium hydroxide solution in a beaker. Pour epoxy diformamide at 85°C into the potassium hydroxide solution, stir and quickly cool to room temperature. A large amount of precipitate is generated, which is filtered to obtain epoxy diformamide potassium salt.

[0058] The above-prepared chloroethyltrimethoxysilane and epoxydicarbonamide potassium salt were mixed in a mass ratio of 60:156, 40 mL of N,N-dimethylformamide (DMF) was added and heated to completely dissolve the chloroethyltrimethoxysilane and epoxydicarbonamide potassium salt to obtain a mixed solution; half of the mixed solution was added to a four-necked flask, and the mixture was stirred in an oil bath at 60°C under nitrogen protection to react, and the remaining half of the mixed solution was added to the four-necked flask by titration at a titration rate of 45 drops / min. After all the titration was completed, the mixture was kept at 100°C for 13 hours to obtain a high-temperature resistant silane coupling agent.

[0059] The high temperature resistant silane coupling agent in the resin-based thermal conductive phase change material raw material of Example 1 was replaced with the high temperature resistant silane coupling agent prepared in this example, and a thin film resin-based thermal conductive phase change material was prepared according to the same method as Example 1.

[0060] Example 4

[0061] The high-temperature resistant silane coupling agent used in Example 4 is the same as that used in Example 1, except that the raw materials of the resin-based phase change material provided in Example 4 include:

[0062] The raw materials of the resin-based phase change material include, by mass fraction: 0.15 parts of the high-temperature resistant silane coupling agent prepared above, 22.45 parts of a bisphenol A type epoxy resin, and 77.35 parts of aluminum powder.

[0063] The film-shaped resin-based heat-conducting phase change material is prepared in the same manner as in Example 1.

[0064] Example 5

[0065] The high-temperature resistant silane coupling agent used in Example 5 is the same as that used in Example 1, except that the raw materials of the resin-based phase change material provided in Example 5 include:

[0066] The raw materials of the resin-based phase change material include, by mass fraction: 0.18 parts of the high-temperature resistant silane coupling agent prepared above, 25.86 parts of a bisphenol A type epoxy resin, and 80.12 parts of aluminum powder.

[0067] The film-shaped resin-based heat-conducting phase change material is prepared in the same manner as in Example 1.

[0068] Comparative Example 1

[0069] Comparative Example 1 differs from Example 1 only in that the high-temperature resistant silane coupling agent in the raw materials of the resin-based heat-conducting phase change material in Example 1 is replaced by a phenyl imide silane. The rest is the same as in Example 1, which will not be repeated here.

[0070] Comparative Example 2

[0071] Comparative Example 2 differs from Example 1 only in that the high-temperature resistant silane coupling agent in the raw materials of the resin-based heat-conducting phase change material in Example 1 is replaced by an ethyl trimethoxysilane. The rest is the same as in Example 1, which will not be repeated here.

[0072] The present application also tests the related properties of the film-shaped resin-based heat-conducting phase change material prepared in the above examples and comparative examples.

[0073] Among them, the test method of thermal conductivity and thermal resistance refers to ASTM D5470; the test method of volume resistivity refers to ASTM D259; the test method of glass transition temperature refers to ASTM D3418; the test method of high-temperature aging for 1000h refers to ASTM D2000. The test results are shown in Table 1.

[0074] Table 1 Related properties of resin-based heat-conducting phase change materials in examples and comparative examples

[0075]

[0076] As can be seen from Table 1, compared to Comparative Examples 1 and 2, the resin-based thermally conductive phase change material prepared using the high-temperature resistant silane coupling agent of the present invention has higher thermal conductivity and lower thermal impedance, indicating better thermal performance. This is due to the introduction of an epoxy structure into the coupling agent, which reduces the movable rotation ability of the chain links. The increased rigidity of the coupling agent has a higher glass transition temperature, giving it good heat resistance and thermal stability. Moreover, it still maintains good thermal impedance after 1000 hours of high-temperature aging. In addition, the volume resistivity is higher than that of Comparative Examples 1 and 2, indicating that the resin-based thermally conductive phase change material prepared by the present invention has better electrical insulation performance while maintaining good thermal conductivity. This is because the high-temperature resistant silane coupling agent can react with the resin and be grafted into the cross-linking system of the resin, reducing the influence of polar groups and improving electrical insulation performance.

[0077] The various aspects, embodiments, features and examples of the present invention should be considered as illustrative in all respects and are not intended to limit the present invention, the scope of which is defined solely by the claims. Other embodiments, modifications and uses will be apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0078] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments using other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0079] Although the present invention has been described with reference to illustrative embodiments, it will be understood by those skilled in the art that various other changes, omissions, and / or additions may be made and that substantial equivalents may be substituted for the elements of the embodiments without departing from the spirit and scope of the present invention. Additionally, many modifications may be made to adapt specific circumstances or materials to the teachings of the present invention without departing from the scope of the present invention. Therefore, it is not intended herein to limit the present invention to the disclosed specific embodiments for carrying out the present invention, but rather to include all embodiments within the scope of the appended claims. Furthermore, unless specifically stated, any use of the terms first, second, etc. does not indicate any order or importance, but rather uses the terms first, second, etc. to distinguish one element from another.

Claims

1. A high temperature resistant silane coupling agent, characterized in that: The structure of the high temperature resistant silane coupling agent is as follows: 。 2. The method for preparing a high temperature resistant silane coupling agent according to claim 1, wherein include: reacting ethyltrimethoxysilane with chlorine to obtain chloroethyltrimethoxysilane; A mixed reaction system containing the chloroethyltrimethoxysilane and epoxydicarbonamide potassium salt is reacted to obtain a high-temperature resistant silane coupling agent.

3. The preparation method according to claim 2, wherein: The mass ratio of the ethyltrimethoxysilane to the chlorine is 82:34-82:

68.

4. The preparation method according to claim 2, characterized in that Specifically include: Providing a uniform first solution and a second solution containing chloroethyltrimethoxysilane, potassium salt of epoxydicarbonamide and a solvent; The first solution is heated to 60-85° C., and under the protection of an inert atmosphere, the second solution is added to the first solution in batches to obtain the mixed reaction system. After the second solution is completely added, the reaction is carried out at 65-100° C.

5. The preparation method according to claim 4, characterized in that: The mass ratio of chloroethyltrimethoxysilane to epoxydicarbonamide potassium salt in the first solution and the second solution is 60:78-60:

156.

6. The preparation method according to claim 4, characterized in that: The reaction time at 65-100°C is 10-13 hours.

7. The preparation method according to claim 4, characterized in that: The solvent includes N,N-dimethylformamide.

8. The preparation method according to claim 4, characterized in that: The second solution was added at a drop rate of 30-45 drops / min.

9. The preparation method according to claim 2, wherein: Epoxydicarbonamide is dissolved in ethanol to obtain an ethanol solution of epoxydicarbonamide, which is then heated to 60-85° C.; the ethanol solution of epoxydicarbonamide is then mixed with a potassium hydroxide solution, stirred, and rapidly cooled to room temperature to obtain a precipitate, which is the epoxydicarbonamide potassium salt.

10. Use of the high temperature resistant silane coupling agent according to claim 1 in the preparation of resin-based thermal conductive phase change materials.

11. A resin-based thermally conductive phase change material, characterized in that: The raw materials of the resin-based thermally conductive phase change material include, by mass, 19.88 g to 25.86 parts of resin, 74.14 to 80.12 parts of thermally conductive filler, and 0.12 to 0.18 parts of a coupling agent, wherein the coupling agent includes the high-temperature resistant silane coupling agent according to claim 1.

12. The resin-based thermally conductive phase change material according to claim 11, characterized in that: The resin includes one or a combination of epoxy resin, rosin resin, and phenolic resin.

13. The method for preparing a resin-based thermally conductive phase change material according to any one of claims 11 to 12, characterized in that: The method comprises the following steps: heating the raw materials to 150-180° C. and uniformly mixing the raw materials, and then forming the raw materials into a film to obtain a film-shaped resin-based thermal conductive phase change material.

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