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

Abstract

The invention provides a high-temperature-resistant silane coupling agent as well as a preparation method and application thereof. The structure of the high-temperature-resistant silane coupling agent is as follows: # imgabs0 #. The preparation method of the high-temperature-resistant silane coupling agent comprises the following steps: reacting ethyltrimethoxysilane with chlorine gas to obtain chloroethyltrimethoxysilane; enabling a mixed reaction system containing chloroethyl trimethoxy silane and epoxy dicarboxamide potassium salt to react, so as to obtain the high-temperature-resistant silane coupling agent. The epoxy structure in the high-temperature-resistant silane coupling agent provided by the invention can reduce the movable rotation capability of a chain link and increase the rigidity of the chain link, so that the high-temperature-resistant silane coupling agent has higher glass transition temperature and is endowed with good heat resistance and heat stability. In addition, the adhesion performance and cohesive strength of the silane coupling agent are also improved. The high-temperature-resistant silane coupling agent is suitable for preparing the resin-based heat-conducting phase-change material and has 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 specifically relates to a high temperature resistant silane coupling agent and a preparation method and 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. Thermally conductive phase change material is a substance with high melting heat that 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 thermally 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 composite materials are phase change composite materials obtained by encapsulating phase change materials with resin materials. For example, the composite mesh structure in high-density polyethylene (HDPE) or styrene-butadiene-styrene block copolymer (SBS) is used to encapsulate the material. Resin-based phase change composite materials have good material coverage, mechanical strength, viscosity and thermal conductivity. Silane coupling agent is usually required as a tackifier for resin-based thermal conductive phase change materials. The principle of silane coupling agent as a tackifier is that it can be combined with thermal conductive fillers such as aluminum oxide, zinc oxide, and aluminum powder, and can be combined with resin polymer materials or adhesives, thereby forming a strong chemical bond at the bonding interface and improving the bonding strength. In addition, in the production of resin-based phase change composite materials, the addition of silane coupling agent can improve the dispersibility and adhesion of thermal conductive fillers in the resin, and at the same time improve the thermal conductivity of the material. However, in production, the melting temperature of the resin usually needs to reach 130°C or above, and the silane coupling agent will volatilize significantly at this temperature, thereby affecting the thermal properties of the resin-based phase change composite materials. In order to improve the heat resistance of the silane coupling agent, the prior art has introduced an aromatic structure with good heat resistance into the silane coupling agent to obtain a new type of silane coupling agent containing an aromatic group, whose initial weight loss temperature exceeds 250°C and 50% weight loss is around 400°C. However, the silane coupling agent is not suitable for application in resin-based phase change materials, because the aromatic-containing coupling agent is not easy to react with the resin, which will reduce the thermal properties of the resin-based phase change composite material, and also reduce the viscosity of the resin-based phase change composite material, increase the dispersibility of thermal conductive fillers such as alumina, make it difficult for the thermal conductive filler to enter the resin system, resulting in a decrease in the thermal conductivity effect. Summary of the invention

[0004] In order to solve all or part of the above technical problems, the present invention provides the following technical solutions:

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

[0006]

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

[0008] A second object of the present invention is to provide a method for preparing a high temperature resistant silane coupling agent, the preparation method comprising:

[0009] Reacting ethyltrimethoxysilane with chlorine to obtain chloroethyltrimethoxysilane;

[0010] A mixed reaction system containing the chloroethyltrimethoxysilane and epoxydiformamide potassium salt is reacted to obtain a high temperature resistant silane coupling agent.

[0011] In some embodiments, the mass ratio of ethyltrimethoxysilane to chlorine is 82:34-82:68. Ethyltrimethoxysilane can be synthesized using trimethoxysilane, α-hexadecene, and a platinum catalyst as raw materials, or commercially available ethyltrimethoxysilane can be used, and the present invention does not specifically limit this.

[0012] In some embodiments, the preparation method specifically includes: providing a uniform first solution and a second solution containing chloroethyltrimethoxysilane, potassium salt of epoxydicarbonamide and a solvent; heating the first solution to 60°C-85°C, 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°C-100°C. 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 generating a large amount of heat and causing a sudden temperature rise, which will lead to a decrease in yield.

[0013] In some embodiments, the mass ratio of chloroethyltrimethoxysilane to potassium salt of epoxydicarbonamide 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 time at 65-100° C. is 10 h-13 h.

[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 of epoxy diformamide 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] The 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] The 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 conventionally used in the field of resin-based thermally conductive phase change materials, and the present invention does not specifically limit this.

[0024] The high temperature resistant silane coupling agent reacts with the resin and is grafted into the cross-linking system of the resin, thereby improving its adhesion strength with the raw materials in the thermal conductive phase change material, and the obtained resin-based thermal conductive phase change material has good toughness. During the reaction, the high temperature resistant silane coupling agent undergoes a hydrolysis reaction, and the three SiOCH3 groups connected to the silicon atom are hydrolyzed to form SiOH, and the three Si-OH groups undergo dehydration condensation to form a low-polysiloxane containing Si-OH; the SiOH in the low-polysiloxane forms a hydrogen bond with the main chain of the resin containing the OH group; during the heating process of the resin-based phase change material, it dehydrates to form a covalent bond, and 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 beneficial effects: the epoxy structure in the high temperature resistant silane coupling agent provided by the present invention reduces the movable rotation ability of the chain link, increases its rigidity, makes it have a higher glass transition temperature, gives it good heat resistance and thermal stability, and its adhesion performance and cohesive strength are also improved. The high temperature resistant silane coupling agent can react with the resin and be grafted into the cross-linking system of the resin, thereby improving its adhesion strength with the raw materials in the thermal conductive phase change material, and the obtained resin-based thermal conductive phase change material has good 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

[0029] The technical solution of the present invention is described in detail below in conjunction with specific embodiments so that those skilled in the art can better understand and implement the technical solution of the present invention. The specific functional details disclosed herein should not be interpreted as limiting, but only as the basis for the claims and as a representative basis for teaching those skilled in the art to adopt the present invention in different ways in 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 epoxy diformamide, which can be prepared by mixing an ethanol solution of epoxy diformamide with a potassium hydroxide solution and precipitating the mixture, and 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 comprises the following steps:

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

[0042] Heat and boil 60g of epoxy diformamide and 52g of ethanol to completely dissolve the solid to obtain an epoxy diformamide solution. Prepare 61g of a potassium hydroxide solution with a concentration of 18g / mL 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, and filter to obtain epoxy diformamide potassium salt.

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

[0044] Figure 1 is the infrared spectrum of the high temperature resistant silane coupling agent prepared in this embodiment, at 1237cm -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 diformamide structure.

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

[0046] Calculated by weight, 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 uniformly mixed, heated to 150° C., and fully stirred to obtain a coating, and the coating is uniformly 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 comprises the following steps:

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

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

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

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

[0054] Example 3

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

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

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

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

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

[0060] Example 4

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

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

[0063] A thin film resin-based thermally conductive phase change material was 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 in Example 1, except that the raw materials of the resin-based phase change material provided in Example 5 include:

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

[0067] A thin film resin-based thermally conductive phase change material was prepared in the same manner as in Example 1.

[0068] Comparative Example 1

[0069] The difference between Comparative Example 1 and Example 1 is that the high temperature resistant silane coupling agent in the resin-based thermal conductive phase change material raw material of Example 1 is replaced with phenylimide silane. The rest is implemented in the same way as Example 1 and will not be repeated here.

[0070] Comparative Example 2

[0071] The only difference between Comparative Example 2 and Example 1 is that the high temperature resistant silane coupling agent in the resin-based thermal conductive phase change material raw material of Example 1 is replaced by ethyltrimethoxysilane, and the rest is implemented in the same way as Example 1, which will not be repeated here.

[0072] The present invention also tests the relevant properties of the thin film resin-based thermally conductive phase change materials prepared in the above embodiments and comparative examples.

[0073] The test methods for thermal conductivity and thermal impedance refer to ASTM D5470; the test method for volume resistivity refers to ASTM D259; the test method for glass transition temperature refers to ASTM D3418; and the test method for high temperature aging for 1000h refers to ASTM D2000. The test results are shown in Table 1.

[0074] Table 1 Relevant properties of resin-based thermally conductive phase change materials in Examples and Comparative Examples

[0075]

[0076] As can be seen from Table 1, compared with Comparative Examples 1 and 2, the resin-based thermally conductive phase change material prepared by using the high-temperature resistant silane coupling agent of the present invention has higher thermal conductivity and lower thermal impedance, indicating that the thermal performance is better. This is due to the introduction of epoxy structure in the coupling agent, which reduces the active rotation ability of the chain link, and the coupling agent has increased rigidity and has a higher glass transition temperature, giving it good heat resistance and thermal stability. And it still maintains good thermal impedance after 1000h of high-temperature aging. And 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, 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 aspects and are not intended to limit the present invention, the scope of the present invention is defined only 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 claimed invention.

[0078] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments with 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 appreciated by those skilled in the art that various other changes, omissions and / or additions may be made without departing from the spirit and scope of the present invention and that the elements of the embodiments may be replaced by substantial equivalents. In addition, many modifications may be made without departing from the scope of the present invention to adapt specific circumstances or materials to the teachings of the present invention. Therefore, it is not intended herein to limit the present invention to the disclosed specific embodiments for performing the present invention, but it is intended that the present invention will include all embodiments within the scope of the appended claims. In addition, 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. A method for preparing a high temperature resistant silane coupling agent, characterized in that: include: Reacting ethyltrimethoxysilane with chlorine to obtain chloroethyltrimethoxysilane; A mixed reaction system containing the chloroethyltrimethoxysilane and epoxydiformamide potassium salt is reacted to obtain a high temperature resistant silane coupling agent.

3. The preparation method according to claim 2, characterized in that: The mass ratio of the ethyltrimethoxysilane to the chlorine gas 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 potassium salt of epoxydicarbonamide in the first solution and the second solution is 60:78-60:156; and / or, the reaction time is 10-13h at 65-100°C; and / or, the solvent comprises N,N-dimethylformamide; And / or, the second solution is added at a dropping speed of 30-45 drops / min.

6. The preparation method according to claim 2, characterized in that: Dissolve epoxy diformamide in ethanol to obtain an ethanol solution of epoxy diformamide, and heat the ethanol solution to 60-85° C.; then mix the ethanol solution of epoxy diformamide with a potassium hydroxide solution, stir, and rapidly cool to room temperature to obtain a precipitate, which is the epoxy diformamide potassium salt.

7. A high temperature resistant silane coupling agent, characterized in that: It is prepared by the method described in any one of claims 2 to 6.

8. Use of the high temperature resistant silane coupling agent according to claim 1 or 7 in the preparation of resin-based thermal conductive phase change materials.

9. 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 coupling agent, wherein the coupling agent includes the high temperature resistant silane coupling agent according to claim 1 or 7; Preferably, the resin includes one or a combination of epoxy resin, rosin resin and phenolic resin.

10. The method for preparing the resin-based thermally conductive phase change material according to claim 9, characterized in that: The method comprises: heating the raw materials to 150-180° C. and uniformly mixing the raw materials, and making the raw materials into a film to obtain a film-shaped resin-based thermal conductive phase change material.

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