A method for improving the dispersion performance of thermally conductive particles in potting compound

Abstract

The present invention provides a method for improving the dispersibility of thermally conductive particles in a potting compound. The method comprises using a coupling agent prepolymer and organically modifying the surface of the thermally conductive particles through a dry surface treatment process to obtain organically modified thermally conductive particles, thereby improving the dispersibility of the thermally conductive particles in the potting compound. The coupling agent prepolymer is prepared by polymerization of a silane coupling agent, butyl acrylate, and 2-butene. The coupling agent prepolymer has a molecular weight of 4000 to 8000. The dry surface treatment process is used to promote the reaction or interaction between the coupling agent prepolymer and the exposed hydroxyl groups on the surface of the thermally conductive particles, so that long chains of the coupling agent prepolymer are grafted onto the surface of the thermally conductive particles to obtain the organically modified thermally conductive particles, thereby significantly improving the dispersibility of the thermally conductive particles in the potting compound.

Description

Technical Field

[0001] The present invention relates to the technical field of potting adhesive materials, and in particular to a method for improving the dispersion performance of heat-conducting particles in potting adhesive. Background Art

[0002] In recent years, with the increasing integration and miniaturization of electronic components, the requirements for potting materials have become increasingly stringent. Silicone potting compounds are widely used in device packaging due to their low heat release during curing, the absence of byproducts, deep curing capability, and long-term elasticity within a temperature range of -50°C to 200°C. Silicone materials inherently have low thermal conductivity, requiring the addition of large amounts of thermally conductive fillers to achieve excellent thermal conductivity. Currently, commonly used thermally conductive particles include aluminum oxide, silica powder, aluminum hydroxide, and boron nitride. The widespread use of silica powder in the potting compound industry is due in part to its low price and in part to its excellent overall performance. However, due to the generally low viscosity of potting compounds, silica powder is prone to sedimentation, forming hard clumps upon settling, necessitating secondary dispersion, which increases costs and can lead to excessive air incorporation into the compound, impacting product performance. Commonly used small molecule coupling agents can improve the compatibility and dispersibility of thermally conductive particles, including silica powder, in potting compounds, but their effectiveness still needs to be improved. Therefore, it is of great practical significance to provide a method for significantly improving the dispersion performance of thermally conductive particles in potting compound. Summary of the Invention

[0003] The object of the present invention is to provide a method for improving the dispersion performance of thermally conductive particles in potting compound. By using the method provided by the present invention, long chains of coupling agent prepolymers are grafted onto the surface of thermally conductive particles, thereby significantly improving the dispersion performance of thermally conductive particles in potting compound.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a method for improving the dispersion performance of thermally conductive particles in a potting compound, using a coupling agent prepolymer and a dry surface treatment process to organically modify the surface of the thermally conductive particles to obtain organically modified thermally conductive particles, thereby improving the dispersion performance of the thermally conductive particles in the potting compound;

[0006] The coupling agent prepolymer is prepared by polymerization reaction of silane coupling agent, butyl acrylate and 2-butene;

[0007] The molecular weight of the coupling agent prepolymer is 4000-8000.

[0008] Preferably, the thermally conductive particles are silicon micropowder, which is flaky, spherical, quasi-spherical or irregularly shaped, and has an average particle size of 10 to 70 μm.

[0009] Preferably, the mass ratio of the coupling agent prepolymer to the thermally conductive particles is 0.5% to 2.0%.

[0010] Preferably, the alkenyl-containing silane coupling agent is one or more of vinyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane.

[0011] Preferably, the molar ratio of the silane coupling agent, butyl acrylate and 2-butene is (0.8-2):(7-10):(10-14).

[0012] Preferably, the dry surface treatment process comprises the following steps:

[0013] The thermally conductive particles are subjected to a first stirring process, a coupling agent prepolymer is added, and then a second stirring process is performed to obtain a mixture;

[0014] The mixture is dried to obtain organically modified thermally conductive particles.

[0015] Preferably, the rotation speed of the first stirring process is 600-800 r / min, and the time of the first stirring process is 20-30 min.

[0016] Preferably, the rotation speed of the second stirring treatment is 1500-2000 r / min, the time of the second stirring treatment is 2-4 hours, and the temperature of the second stirring treatment is 50-70°C.

[0017] Preferably, the drying temperature is 100-120° C., and the drying time is 6-12 hours.

[0018] The present invention provides a method for improving the dispersibility of thermally conductive particles in potting compound. The method employs a coupling agent prepolymer, and through a dry surface treatment process, organically modifies the surface of the thermally conductive particles to obtain organically modified thermally conductive particles, thereby improving the dispersibility of the thermally conductive particles in potting compound. The coupling agent prepolymer is prepared by polymerization of a silane coupling agent, butyl acrylate, and 2-butene; the coupling agent prepolymer has a molecular weight of 4,000 to 8,000. Through the dry surface treatment process, the coupling agent prepolymer is encouraged to react or interact with exposed hydroxyl groups on the surface of the thermally conductive particles, thereby grafting long chains of the coupling agent prepolymer onto the surface of the thermally conductive particles. This results in the organically modified thermally conductive particles, thus significantly improving the dispersibility of the thermally conductive particles in potting compound. DETAILED DESCRIPTION

[0019] The present invention provides a method for improving the dispersion performance of thermally conductive particles in a potting compound, using a coupling agent prepolymer and a dry surface treatment process to organically modify the surface of the thermally conductive particles to obtain organically modified thermally conductive particles, thereby improving the dispersion performance of the thermally conductive particles in the potting compound;

[0020] The coupling agent prepolymer is prepared by polymerization reaction of silane coupling agent, butyl acrylate and 2-butene;

[0021] The molecular weight of the coupling agent prepolymer is 4000-8000.

[0022] In the present invention, unless otherwise specified, the raw materials used are conventional commercial products in the field.

[0023] In the present invention, the coupling agent prepolymer is preferably added in the form of a coupling agent prepolymer solution. In the present invention, the coupling agent prepolymer is prepared by polymerization of a silane coupling agent, butyl acrylate and 2-butene, comprising the following steps:

[0024] In a nitrogen atmosphere, a silane coupling agent, butyl acrylate, a silane coupling agent, benzoyl peroxide, dodecyl mercaptan and toluene are mixed, and then a first heat treatment is performed at 80 to 90° C. for 1.5 to 3 hours to obtain a mixture;

[0025] After the mixture and dicumyl peroxide are mixed, a second heating treatment is performed at 110-130° C. for 1.5-3 hours to obtain a coupling agent prepolymer solution.

[0026] In the present invention, the molecular weight of the coupling agent prepolymer is 4000 to 8000, preferably 4500 to 6000. Controlling the molecular weight of the coupling agent prepolymer within this range facilitates grafting long chains of the coupling agent prepolymer onto the surface of the thermally conductive particles, thereby obtaining organically modified thermally conductive particles, thereby significantly improving the dispersion of the thermally conductive particles within the potting compound.

[0027] In the present invention, the thermally conductive particles are preferably silica powder. In the present invention, the silica powder is preferably flaky, spherical, quasi-spherical, or irregularly shaped. In the present invention, the average particle size of the silica powder is preferably 10 to 70 μm. Controlling the average particle size of the silica powder within this range facilitates the grafting of long chains of the coupling agent prepolymer onto the surface of the silica powder.

[0028] In the present invention, the mass ratio of the coupling agent prepolymer to the thermally conductive particles is preferably 0.5% to 2.0%, and more preferably 0.8% to 1.6%. Controlling the mass ratio of the coupling agent prepolymer to the thermally conductive particles within this range is beneficial for enhancing the effect of the organic modification and significantly improving the dispersion of the thermally conductive particles in the potting compound.

[0029] In the present invention, the alkenyl-containing silane coupling agent is preferably one or more of vinyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane.

[0030] In the present invention, the molar ratio of the silane coupling agent, butyl acrylate, and 2-butene is preferably (0.8-2):(7-10):(10-14), and more preferably (0.9-1.5):(8-9):(11-12). Controlling the molar ratio of the silane coupling agent, butyl acrylate, and 2-butene in the coupling agent prepolymer within the above range is beneficial for enhancing the effect of the organic modification and significantly improving the dispersion performance of the thermally conductive particles in the potting compound.

[0031] In the present invention, the dry surface treatment process comprises the following steps:

[0032] The thermally conductive particles are subjected to a first stirring process, a coupling agent prepolymer is added, and then a second stirring process is performed to obtain a mixture;

[0033] The mixture is dried to obtain organically modified thermally conductive particles.

[0034] In the present invention, the rotation speed of the first stirring treatment is preferably 600 to 800 r / min. In the present invention, the time of the first stirring treatment is preferably 20 to 30 minutes. The present invention controls the rotation speed and time of the first stirring treatment within the above range to improve the mixing effect of the amount ratio of the thermal conductive particles and the silane coupling agent, butyl acrylate and 2-butene, thereby improving the organic modification effect.

[0035] In the present invention, the rotation speed of the second stirring process is preferably 1500-2000 r / min. In the present invention, the duration of the second stirring process is preferably 2-4 hours. In the present invention, the temperature of the second stirring process is 50-70°C. The present invention controls the rotation speed, duration, and temperature of the second stirring process within the above ranges to enhance the mixing effect of the thermally conductive particles and the coupling agent prepolymer, and promotes sufficient reaction and hydrogen bond formation between the two, thereby enhancing the organic modification effect and significantly improving the dispersion performance of the thermally conductive particles in the potting compound.

[0036] In the present invention, the drying method is preferably vacuum drying. In the present invention, the drying temperature is preferably 100-120°C; and the drying time is preferably 6-12 hours. In the present invention, the drying method, temperature, and time are controlled within the above ranges to remove residual reagents.

[0037] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0038] Example 1

[0039] A method for improving the dispersion performance of thermally conductive particles in a potting compound comprises using a coupling agent prepolymer and performing organic modification on the surface of the thermally conductive particles through a dry surface treatment process to obtain organically modified thermally conductive particles, thereby improving the dispersion performance of the thermally conductive particles in the potting compound.

[0040] The coupling agent prepolymer is prepared by polymerization of a silane coupling agent, butyl acrylate and 2-butene, and the steps are as follows:

[0041] In a nitrogen atmosphere, a silane coupling agent, γ-methacryloxypropyltrimethoxysilane, butyl acrylate, 2-butene, benzoyl peroxide, dodecylmercaptan, and toluene were mixed, and then subjected to a first heat treatment at 90° C. for 3 hours to obtain a mixture;

[0042] The mixture and dicumyl peroxide were mixed, and then subjected to a second heating treatment at 120° C. for 2 hours to obtain a coupling agent prepolymer solution with a solid content of 40%.

[0043] The molar ratio of the silane coupling agent, butyl acrylate and 2-butene is 1.5:10:10.

[0044] The molecular weight of the coupling agent prepolymer is 5000;

[0045] The thermally conductive particles are silicon micropowder, which is in flake form and has an average particle size of 50 μm.

[0046] The mass ratio of the coupling agent prepolymer to the silicon powder in the coupling agent prepolymer solution is 1%;

[0047] The steps of the dry surface treatment process are as follows:

[0048] The silicon powder was stirred at 700 r / min for 30 minutes, and then the coupling agent prepolymer solution was added, followed by a second stirring at 1800 r / min for 2 hours to obtain a mixture;

[0049] The mixture was dried at 70° C. for 4 hours to obtain organically modified thermally conductive particles.

[0050] Application Example 1

[0051] The organically modified thermally conductive particles prepared in Example 1 were used as raw materials to prepare an organic silicone potting compound in the following steps:

[0052] Preparation of component A: 2000 g of vinyl silicone oil and 3000 g of the organically modified thermally conductive particles obtained in Example 1 were dispersed at 120° C. After 1 hour, 2 g of black color paste and 10 g of platinum water were added and fully dispersed to obtain component A.

[0053] Preparation of component B: 2000 g of vinyl silicone oil and 3000 g of the organically modified thermally conductive particles obtained in Example 1 were dispersed at 120° C. After 1 hour, 100 g of hydrogenated silicone oil and 0.2 g of inhibitor were added to obtain component B.

[0054] Application Example 2

[0055] The organically modified thermally conductive particles prepared in Example 1 were used as raw materials to prepare an organic silicone potting compound in the following steps:

[0056] Preparation of component A: 2000 g of vinyl silicone oil and 4000 g of the organically modified thermally conductive particles obtained in Example 1 were dispersed at 120° C. After 1 hour, 2 g of black color paste and 10 g of platinum water were added and fully dispersed to obtain component A.

[0057] Preparation of component B: 2000 g of vinyl silicone oil and 4000 g of the organically modified thermally conductive particles obtained in Example 1 were dispersed at 120° C. After 1 hour, 100 g of hydrogenated silicone oil and 0.2 g of inhibitor were added to obtain component B.

[0058] Comparative Example

[0059] The steps for preparing silicone potting compound using unmodified silica powder as raw material are as follows:

[0060] Preparation of component A: Disperse 2000g of vinyl silicone oil and 3000g of silica powder at 120°C. After 1 hour, add 2g of black color paste and 10g of platinum water and disperse thoroughly to obtain component A.

[0061] Preparation of component B: 2000 g of vinyl silicone oil and 3000 g of silicon powder were dispersed at 120° C. After 1 hour, 100 g of hydrogenated silicone oil and 0.2 g of inhibitor were added to obtain component B.

[0062] The viscosities of components A and B in the above Application Examples 1 and 2, as well as the comparative example, were tested and recorded in Table 1. The physical properties of the cured specimens after components A and B were mixed uniformly in a 1:1 ratio and allowed to stand at room temperature for 24 hours were recorded in Table 1.

[0063] Table 1 Viscosity of silicone potting compound and physical properties after curing

[0064]

[0065] As shown in Table 1, the viscosities of components A and B in the application example are significantly lower than those in the comparative example. This indicates that the organically modified thermally conductive particles prepared in Example 1 have longer organic chains on their surfaces, which enhance their compatibility with the polymer matrix. Consequently, the tensile strength and elongation at break of the application example are also superior to those of the comparative example. The improved thermal conductivity of the application example is primarily due to the homemade silane treatment agent effectively enhancing the wettability between the organically modified thermally conductive particles and the silicone oil, thereby reducing the thermal resistance at the interface and improving the overall thermal conductivity of the material. This demonstrates that the organically modified thermally conductive particles prepared in Example 1 significantly improve their dispersion within the potting compound.

[0066] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for improving the dispersion performance of thermally conductive particles in a potting compound, characterized in that: The coupling agent prepolymer is used to organically modify the surface of the thermally conductive particles through a dry surface treatment process to obtain organically modified thermally conductive particles, thereby improving the dispersion performance of the thermally conductive particles in the potting compound. The coupling agent prepolymer is prepared by polymerization reaction of silane coupling agent, butyl acrylate and 2-butene; The molecular weight of the coupling agent prepolymer is 4000 to 8000; The silane coupling agent is one or more of vinyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane; The molar ratio of the silane coupling agent, butyl acrylate and 2-butene is (0.8-2): (7-10): (10-14).

2. The method according to claim 1, characterized in that The thermally conductive particles are silicon micropowder, which is in the form of flakes, spheres, quasi-spherical or irregular shapes, and has an average particle size of 10 to 70 μm.

3. The method according to claim 1, characterized in that The mass ratio of the coupling agent prepolymer to the thermally conductive particles is 0.5% to 2.0%.

4. The method according to claim 1, wherein the dry surface treatment process comprises the following steps: The thermally conductive particles are subjected to a first stirring process, a coupling agent prepolymer is added, and then a second stirring process is performed to obtain a mixture; The mixture is dried to obtain organically modified thermally conductive particles.

5. The method according to claim 4, characterized in that The rotation speed of the first stirring process is 600-800 r / min, and the time of the first stirring process is 20-30 min.

6. The method according to claim 4, characterized in that The rotation speed of the second stirring process is 1500-2000 r / min, the time of the second stirring process is 2-4 hours, and the temperature of the second stirring process is 50-70°C.

7. The method according to claim 4, characterized in that The drying temperature is 100-120° C., and the drying time is 6-12 hours.

Images