Silver-coated hollow glass bead and organic silicon heat-conducting pouring sealant as well as preparation method and application of silver-coated hollow glass bead and organic silicon heat-conducting pouring sealant

Abstract

The invention relates to a silver-coated hollow glass bead, an organosilicon heat-conducting pouring sealant and a preparation method and application thereof, and the preparation method of the silver-coated hollow glass bead comprises the following steps: S1, carrying out oil removal treatment on the hollow glass bead to obtain the pretreated hollow glass bead; and S2, mixing the pretreated hollow glass beads, polyacrylic resin, a silver-ammonia solution, a reducing agent and an alkaline agent to form a reaction solution, and carrying out a reduction reaction to obtain the silver-coated hollow glass beads. According to the invention, polyacrylic resin is added as a dispersing agent, so that the organosilicone heat-conducting pouring sealant prepared from the prepared silver-coated hollow glass beads not only has good hardness, but also keeps low density, and meanwhile, the heat conductivity coefficient is greatly improved, and the heat conductivity coefficient is obviously improved.

Description

Technical Field

[0001] The present invention relates to the technical field of potting adhesive products, and more specifically, to a silver-coated hollow glass microsphere, an organosilicon thermal conductive potting adhesive, and a preparation method and application thereof. Background Art

[0002] As a key material for thermal management of electronic devices, the organosilicon thermal conductive potting adhesive fills the gaps between electronic components under pressure during use to achieve the dual functions of heat conduction and encapsulation. With the rapid development of emerging industries such as wearable electronic devices, new energy vehicles, drones, and robots, two core requirements are put forward for the organosilicon thermal conductive potting adhesive: low density and high thermal conductivity. Currently, in the low-density potting adhesive products on the market (density < 1.2 g / cm 3 ), the density is generally reduced by adding a certain number of hollow glass microspheres. However, due to the weak thermal conductivity of the hollow glass microspheres, the application of the organosilicon thermal conductive potting adhesive filled with hollow glass microspheres in emerging industries is greatly restricted.

[0003] To solve the above problems, the thermal conductivity can be improved by plating a layer of silver on the surface of the hollow glass microspheres, thereby improving the thermal conductivity. Since the glass microspheres are non-conductive, chemical plating is generally used to plate silver on the surface of the hollow glass microspheres. For example, in a Chinese patent for a preparation method of plating silver on the surface of hollow glass microspheres, but in the sensitization process of this preparation method, SnCl2 solution needs to be used, resulting in the residual Sn element in the obtained silver-plated hollow glass microspheres. If the silver-plated hollow glass microspheres are used in the organosilicon thermal conductive potting adhesive, the residual Sn element will cause partial failure of the free radical curing agent in the organosilicon thermal conductive potting adhesive, resulting in poor hardness after curing of the organosilicon thermal conductive potting adhesive, and thus may crack due to pressure during use, unable to meet the corresponding use requirements. Summary of the Invention

[0004] The primary object of the present invention is to overcome the problem that the existing silver-plated hollow glass microspheres cannot enable the organosilicon thermal conductive potting adhesive to have both high hardness and high thermal conductivity, and provide a preparation method of silver-coated hollow glass microspheres. By adding polyacrylic resin as a dispersant, the organosilicon thermal conductive potting adhesive prepared from the obtained silver-coated hollow glass microspheres not only has good hardness, but also has a more obvious improvement in thermal conductivity.

[0005] A further object of the present invention is to provide a silver-coated hollow glass microsphere.

[0006] Another object of the present invention is to provide the application of the above silver-coated hollow glass microspheres in the preparation of an organosilicon thermal conductive potting adhesive.

[0007] Another object of the present invention is to provide an organosilicon thermal conductive potting adhesive.

[0008] The above object of the present invention is achieved by the following technical solutions:

[0009] A preparation method of silver-coated hollow glass microspheres, comprising the following steps:

[0010] S1. Perform degreasing treatment on the hollow glass microspheres to obtain pretreated hollow glass microspheres;

[0011] S2. Mix the pretreated hollow glass microspheres, polyacrylic resin, silver ammonia solution, reducing agent and alkali agent to form a reaction solution, and carry out a reduction reaction to obtain the silver-coated hollow glass microspheres.

[0012] Performing the degreasing treatment in step S1 provides a basis for subsequent successful silver plating.

[0013] The inventors of the present invention have found through research that adding polyacrylic resin as a dispersant in step S2. On the one hand, the carboxyl groups of the polyacrylic resin bond with the hydroxyl groups on the surface of the hollow glass microspheres, so as to be evenly adsorbed on the surface of the hollow glass microspheres; on the other hand, the carboxyl groups of the polyacrylic resin can form electrostatic adsorption on silver ions, so as to be evenly distributed on the surface of the hollow glass microspheres, and then a reduction reaction occurs, realizing continuous and dense coating of silver on the surface of the hollow glass microspheres, thereby improving the thermal conductivity of the silicone thermal conductive potting adhesive prepared from the silver-coated hollow glass microspheres. In addition, using polyacrylic resin as a dispersant in the preparation process of the silver-coated hollow glass microspheres of the present invention will not cause the free radical curing agent to fail, so that the silicone thermal conductive potting adhesive has good hardness after curing, avoiding the problem of possible cracking due to pressure during use, and can meet the corresponding use requirements.

[0014] That is, the silver-coated hollow glass microspheres prepared by the preparation method of the present invention are used to prepare a silicone thermal conductive potting adhesive, which can make the silicone thermal conductive potting adhesive have both high hardness and high thermal conductivity.

[0015] Preferably, in step S1, the average particle size of the hollow glass microspheres is 5-150 μm.

[0016] Preferably, in step S1, the true density of the hollow glass microspheres is 0.1-50 g / cm 3 .

[0017] The degreasing in step S1 can adopt common means in the art, such as alkali washing.

[0018] Preferably, in step S1, the process of the degreasing treatment is: soaking with an alkali solution.

[0019] More preferably, the alkali solution is a sodium hydroxide solution with a concentration of 0.001-0.1 mol / L.

[0020] More preferably, the soaking time is 0.1-1 h.

[0021] Preferably, in step S1, after the degreasing treatment, an acid treatment step is further included. After the acid treatment, more hydroxyl groups can be exposed on the surface of the hollow glass microspheres, which is beneficial to further improve the thermal conductivity of the silicone thermal conductive potting adhesive.

[0022] More preferably, the acid in the acid treatment is at least one of dilute nitric acid and dilute hydrochloric acid.

[0023] Even more preferably, the acid in the acid treatment is dilute nitric acid. When the acid in the acid treatment is dilute nitric acid, the degree of improvement in the thermal conductivity of the silicone thermal conductive potting adhesive made of the silver-coated hollow glass microspheres is greater. The reason may be that when using nitric acid, it can avoid the formation of silver chloride in the silver layer due to the residual chloride ions in the silver plating process when using hydrochloric acid. A purer silver layer results in better thermal conductivity.

[0024] More preferably, the mass concentration of the acid in the acid treatment is 0.001 - 0.1 mol / L.

[0025] More preferably, the time of the acid treatment is 0.1 - 1 h.

[0026] More preferably, after the acid treatment, a washing step is further included.

[0027] Even more preferably, the washing process is: washing with water until the conductivity is lower than 50 μS / m.

[0028] Preferably, in step S2, the mass ratio of the polyacrylic acid resin to the silver element in the reaction solution is (1×10 -6 ~1×10 -5 ):1.

[0029] Preferably, in step S2, the mass ratio of the pretreated hollow glass microspheres to the polyacrylic acid resin in the reaction solution is 1:(1×10 -7 ~1×10 -6 ).

[0030] Preferably, in step S2, the mass concentration of the polyacrylic acid resin in the reaction solution is 1×10 -5 ~1×10 -4 .

[0031] Preferably, in step S2, the number-average molecular weight of the polyacrylic acid resin is 1000 - 10000.

[0032] Preferably, in step S2, the polyacrylic acid resin is mixed in the form of a polyacrylic acid resin solution.

[0033] Preferably, in step S2, the mixing sequence is as follows: first, mix hollow glass microspheres and silver ammonia solution, then add polyacrylic resin and alkali agent, and then add reducing agent.

[0034] Preferably, in step S2, the preparation process of the silver ammonia solution is as follows: take 300 g of deionized water, add 1 - 30 g of silver nitrate, and add 10 - 100 mL of ammonia water for mixing.

[0035] More preferably, in step S2, the preparation process of the silver ammonia solution is as follows: take 300 g of deionized water, add 5 - 20 g of silver nitrate, and add 20 - 70 mL of ammonia water for mixing.

[0036] More preferably, the mass concentration of the ammonia water is 15 - 40%.

[0037] Preferably, in step S2, the reducing agent is at least one of hydrazine hydrate, ascorbic acid, or triethanolamine.

[0038] Preferably, in step S2, the reducing agent is mixed in the form of a reducing solution.

[0039] More preferably, the mass concentration of the reducing agent in the reducing solution is 4 - 24%.

[0040] In the present invention, the addition of the alkali agent is to adjust the pH of the reaction solution to be alkaline.

[0041] Preferably, in step S2, the alkali agent is at least one of sodium hydroxide, sodium carbonate, or sodium bicarbonate.

[0042] Preferably, in step S2, the alkali agent is mixed with other components in the form of an alkali solution.

[0043] More preferably, the mass concentration of the alkali agent in the alkali solution is 0.9 - 24%.

[0044] Further preferably, the mass concentration of the alkali agent in the alkali solution is 0.9 - 5%.

[0045] Preferably, in step S2, the reaction time of the reduction reaction is 0.1 - 1 h.

[0046] Preferably, in step S2, the reaction temperature of the reduction reaction is 10 - 90 °C.

[0047] Preferably, in step S2, the mixing includes a stirring step.

[0048] More preferably, the stirring rate is 100 - 800 r / min.

[0049] Preferably, in step S2, after the reduction reaction, there are also cleaning and drying steps.

[0050] More preferably, the drying process is as follows: drying at 20-100°C for 10-48 hours.

[0051] More preferably, the cleaning process is as follows: after centrifugation, taking the solid and washing it with water until the conductivity is lower than 50 μS / m.

[0052] Further preferably, the rotation speed of the centrifugation is 100-3000 rpm.

[0053] Preferably, in step S2, the silver content in the silver-coated hollow glass microspheres is 1-20 wt.%.

[0054] More preferably, in step S2, the silver content in the silver-coated hollow glass microspheres can be 1 wt.%, 5 wt.%, 9.5 wt.%, 10 wt.%, 13.6 wt.%, 15 wt.% or 20 wt.%.

[0055] The silver-coated hollow glass microspheres prepared by the above preparation method are also within the protection scope of the present invention.

[0056] The present invention also protects the application of the above silver-coated hollow glass microspheres in the preparation of silicone heat-conducting potting adhesives.

[0057] Preferably, the silicone heat-conducting potting adhesive is a two-component silicone heat-conducting potting adhesive or a one-component silicone heat-conducting potting adhesive.

[0058] A silicone heat-conducting potting adhesive, comprising component A and component B with a mass ratio of 1:(0.8-1.2); by weight, component A comprises the following components: 50-80 parts of vinyl-terminated silicone oil, 5-30 parts of the above silver-coated hollow glass microspheres; component B comprises the following components: 50-80 parts of vinyl-terminated silicone oil, 5-30 parts of the above silver-coated hollow glass microspheres, 1-10 parts of a free radical curing agent.

[0059] Preferably, component A comprises the following components: 65-70 parts of vinyl-terminated silicone oil, 20-25 parts of the above silver-coated hollow glass microspheres; component B comprises the following components: 65-70 parts of vinyl-terminated silicone oil, 20-25 parts of the above silver-coated hollow glass microspheres, 1-5 parts of a free radical curing agent.

[0060] Preferably, the cyclic content of the vinyl-terminated silicone oil ≤ 100 ppm, and the cyclic body is a cyclic siloxane compound from trimer (D3) to eicosamer (D20).

[0061] In the present invention, the cyclic content of the vinyl-terminated silicone oil is measured by the GC-MS method.

[0062] Preferably, the viscosity of the vinyl-terminated silicone oil is 10-5000 cP.

[0063] In the present invention, the test standard for the viscosity of the vinyl-terminated silicone oil is GB / T 2794-2013. The test conditions are as follows: using a DV2T rotational viscometer from BROOKFIELD, rotor No. 4, rotation speed 100 rpm, and temperature 25°C.

[0064] Preferably, the vinyl content of the vinyl-terminated silicone oil is 0.1 to 3 wt.%.

[0065] Preferably, the free radical curing agent is an organic peroxide curing agent.

[0066] More preferably, the organic peroxide curing agent is at least one of 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, hexane peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, and tert-butyl peroxy(2-ethylhexanoate).

[0067] Preferably, component A further includes 2 to 30 parts of a flame retardant.

[0068] Preferably, component B further includes 1 to 20 parts of a flame retardant.

[0069] The flame retardants in component A and component B can be the same or different.

[0070] More preferably, the flame retardant is at least one of hydroxides, oxides, or expanded graphite.

[0071] Further preferably, the hydroxide is at least one of aluminum hydroxide, magnesium hydroxide, and calcium hydroxide.

[0072] Further preferably, the oxide is at least one of silicon dioxide or aluminum oxide.

[0073] Preferably, the polymerization inhibitor is at least one of 2,5-di-tert-butylhydroquinone, tert-butylhydroquinone, and p-methoxyphenol.

[0074] Preferably, component A and / or component B further includes 0.1 to 1 part of a dispersant.

[0075] More preferably, the dispersant is an alkylsiloxane, and the alkyl substituent in the alkylsiloxane has 1 to 20 carbon atoms. For example, the alkylsiloxane can be dodecyltriethoxysilane.

[0076] Preferably, component A and / or component B further includes 1 to 15 parts of a diluent.

[0077] More preferably, the diluent is at least one of white oil, cyclohexane, or toluene.

[0078] Further preferably, the boiling point of the white oil is 150 - 300 °C.

[0079] Preferably, the component B further includes 0.1 - 1 part of inhibitor.

[0080] More preferably, the inhibitor is at least one of 2,5 - di - tert - butylhydroquinone, monoterbutylhydroquinone or p - hydroxyanisole.

[0081] The preparation method of the above - mentioned silicone thermal conductive potting adhesive includes the following steps: Weigh each component of component A, and stir at 10 - 40 °C in a vacuum environment for 0.1 - 1 h to obtain component A; Weigh each component of component B, and stir at 10 - 40 °C in a vacuum environment for 0.1 - 1 h to obtain component B.

[0082] Preferably, the stirring device is a planetary stirrer.

[0083] More preferably, the stirring rate of the high - speed dispersion disc in the planetary stirrer is 5 - 50 Hz, and the stirring rate of the scraping edge slurry is 5 - 50 Hz.

[0084] Preferably, the pressure in the vacuum environment is - 0.2 - 0.5 MPa.

[0085] The using method of the above - mentioned silicone thermal conductive potting adhesive includes the following steps: The silicone thermal conductive potting adhesive is cured at 50 - 150 °C for 0.1 - 2 h.

[0086] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0087] By adding polyacrylic resin as a dispersant, the silicone thermal conductive potting adhesive prepared from silver - coated hollow glass microspheres not only has good hardness, but also has a large increase in thermal conductivity while maintaining low density, and the improvement of thermal conductivity is obvious. Specific Embodiments

[0088] In order to more clearly and completely describe the technical solution of the present invention, the following further details the present invention through specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, and various changes can be made within the scope defined by the rights of the present invention.

[0089] Example 1

[0090] This example provides a preparation method of silver - coated hollow glass microspheres, including the following steps:

[0091] (1) Take hollow glass microspheres with an average particle size of 60 μm and a true density of 0.2 g / cm 3Hollow glass microspheres were cleaned and soaked in 0.01 mol / L sodium hydroxide solution at 25°C for 0.5 h to remove organic impurities on the surface; then, they were soaked in 0.01 mol / L dilute nitric acid for 0.5 h, and then washed with deionized water until the conductivity was lower than 50 μS / m to obtain pretreated hollow glass microspheres;

[0092] (2) The following solutions were prepared respectively at 35°C:

[0093] The mother liquor of polyacrylic acid resin (the number-average molecular weight of polyacrylic acid resin is 2000, and the manufacturer is Bangpu Import and Export Co., Ltd.) was added to deionized water while stirring to obtain a polyacrylic acid resin solution with a mass concentration of 9.0×10 -4 of polyacrylic acid resin solution;

[0094] 3 g of sodium hydroxide was added to 100 g of deionized water while stirring to obtain a sodium hydroxide solution;

[0095] 14.26 g of hydrazine hydrate was added to 100 g of deionized water while stirring and kept at a constant temperature of 35°C to obtain a reducing agent solution;

[0096] 300 g of deionized water was taken, 5.31 g of silver nitrate was added, and 21.75 mL of 25 wt.% ammonia water was slowly added while stirring and kept at a constant temperature of 35°C to obtain a silver ammonia solution;

[0097] (3) All the above-prepared silver ammonia solution was transferred to a 1 L reaction kettle, 64 g of pretreated hollow glass microspheres were added and stirred at 500 r / min, then 0.2 g of sodium hydroxide solution and 0.02 g of polyacrylic acid resin solution were added and stirred evenly, and then 11.7 g of reducing solution was quickly added to carry out the reaction of silver plating on the surface of the pretreated hollow glass microspheres. The reaction temperature was 35°C and the reaction time was 0.5 h.

[0098] (4) It was transferred to a 150-mesh filter bag, the filter bag was placed in a plate centrifuge, the plate centrifuge was set at 1000 rpm, and it was washed with deionized water until the conductivity was lower than 50 μS / m to remove the reducing solution and sodium hydroxide solution, and then transferred to a blast drying oven at 60°C and dried for 24 h to obtain silver-coated hollow glass microspheres. Among them, the silver content in the obtained silver-coated hollow glass microspheres was 5 wt%.

[0099] Example 2

[0100] This embodiment provides a method for preparing silver-coated hollow glass microspheres. Different from Embodiment 1, in step (2), the method for preparing the silver ammonia solution is as follows: 300 g of deionized water, 10.62 g of silver nitrate is added, and 43.5 mL of ammonia water with a concentration of 25 wt.% is slowly added while stirring; in step (3), the polyacrylic acid resin solution is 0.04 g, the reducing solution is 23.4 g, and the silver content in the obtained silver-coated hollow glass microspheres is 9.5 wt.%.

[0101] Embodiment 3

[0102] This embodiment provides a method for preparing silver-coated hollow glass microspheres. Different from Embodiment 1, in step (2), the method for preparing the silver ammonia solution is as follows: 300 g of deionized water, 15.93 g of silver nitrate is added, and 65.25 mL of ammonia water with a concentration of 25 wt.% is slowly added while stirring; in step (3), the polyacrylic acid resin solution is 0.06 g, the reducing solution is 35.1 g, and the silver content in the obtained silver-coated hollow glass microspheres is 13.6 wt.%.

[0103] Embodiment 4

[0104] This embodiment provides a method for preparing silver-coated hollow glass microspheres. Different from Embodiment 1, in step (1), dilute nitric acid is replaced with dilute hydrochloric acid.

[0105] Embodiment 5

[0106] This embodiment provides a method for preparing silver-coated hollow glass microspheres. Different from Embodiment 1, in step (1), the dilute nitric acid soaking treatment is not carried out.

[0107] Comparative Example 1

[0108] This comparative example provides a method for preparing comparative hollow glass microspheres, and the comparative hollow glass microspheres are obtained through the following steps: Take the pretreated hollow glass microspheres in step (1) of Embodiment 1 and transfer them to a 60°C blast drying oven for drying for 24 h.

[0109] Comparative Example 2

[0110] This comparative example provides a method for preparing comparative hollow glass microspheres. Different from Embodiment 1, the polyacrylic acid resin solution in step (3) is replaced with a gelatin solution with a mass concentration of 9.0×10 -4 of.

[0111] Comparative Example 3

[0112] This comparative example provides a method for preparing comparative hollow glass microspheres. Different from Embodiment 1, the polyacrylic acid resin solution in step (3) is replaced with an aqueous solution of sodium dodecylbenzenesulfonate with a mass concentration of 9.0×10 -4 of.

[0113] Performance Test

[0114] Take the silver-coated hollow glass microspheres of each example and the comparative hollow glass microspheres of the comparative example to prepare silicone thermally conductive potting adhesives. The silicone thermally conductive potting adhesives are composed of component A and component B. By weight, component A includes the following components: 66.05 parts of vinyl-terminated silicone oil, 20.7 parts of silver-coated hollow glass microspheres or comparative hollow glass microspheres, 4.5 parts of aluminum hydroxide, 2 parts of expanded graphite, 0.25 part of dodecyltriethoxysilane, and 6.5 parts of white oil; component B includes the following components: 66.05 parts of vinyl-terminated silicone oil, 20.7 parts of silver-coated hollow glass microspheres or comparative hollow glass microspheres, 3 parts of aluminum hydroxide, 0.25 part of dodecyltriethoxysilane, 6.5 parts of white oil, 3 parts of 2,4-dichlorobenzoyl peroxide, and 0.5 part of 2,5-di-tert-butylhydroquinone. Among them, the viscosity of the vinyl-terminated silicone oil is 50 cP, and the boiling point of the white oil is 230 °C.

[0115] The preparation method of the silicone thermally conductive potting adhesive includes the following steps: Weigh each component of component A and component B according to the above formula, mix them separately and stir with a planetary stirrer in a vacuum environment of -0.1 MPa for 0.5 h. Ensure that the temperature of the material is maintained at 10-30 °C during stirring. The stirring rate of the high-speed dispersion disk is 25 Hz, and the stirring rate of the scraping edge slurry is 25 Hz, thus obtaining component A and component B.

[0116] After storing the prepared silicone thermally conductive potting adhesive for six months, test the viscosity and density of component A and component B respectively, and observe their appearance. The results are shown in Table 1. Among them, the viscosity is measured according to the GB / T 2794-2013 standard with a DV2T rotational viscometer from BROOKFIELD Company, rotor No. 4, rotation speed 100 rpm, at 25 °C; the density is measured according to the GB / T13477.2-2002 standard.

[0117] Stir component A and component B of the silicone thermally conductive potting adhesive evenly for 5 min respectively. Mix and stir component A and component B in a weight ratio of 1:1 for 5 min, and heat and bake at 125 °C for 1 h to complete curing, and test their hardness and thermal conductivity. The results are shown in Table 1. Among them, the hardness is measured according to the GB / T531.1-2008 standard; the thermal conductivity is measured according to the ASTM-D5470 standard; the content of the cyclic body (D3-D20) / ppm is measured by the GC-MS method; the flame retardant grade is the UL-94 flame retardant grade.

[0118] Table 1 Results of Each Performance Test

[0119]

[0120]

[0121] As can be seen from Table 1, the hardness of the silicone thermally conductive potting adhesive made of the silver-coated hollow glass microspheres prepared in Examples 1 to 5 is above 50 shore A, and the thermal conductivity is above 0.5 W / m·K. This indicates that the silicone thermally conductive potting adhesive made of the silver-coated hollow glass microspheres prepared by the present invention not only has good hardness, but also has a large increase in thermal conductivity while maintaining low density, and the improvement of thermal conductivity is obvious.

[0122] Since the comparative hollow glass microspheres prepared in Comparative Example 1 are not silver-plated, the silicone thermally conductive potting adhesive made thereof has a lower thermal conductivity.

[0123] In Comparative Example 2, the polyacrylic resin was replaced with the commonly used dispersant gelatin. The degree of increase in the thermal conductivity of the silicone thermally conductive potting adhesive made of the prepared comparative hollow glass microspheres is small, and the improvement of the thermal conductivity is not obvious, and it is impossible to make the silicone thermally conductive potting adhesive have both high hardness and high thermal conductivity at the same time.

[0124] In Comparative Example 3, the polyacrylic resin was replaced with the commonly used dispersant sodium dodecylbenzenesulfonate. The hardness of the silicone thermally conductive potting adhesive made of the prepared comparative hollow glass microspheres is not good, and it is impossible to make the silicone thermally conductive potting adhesive have both high hardness and high thermal conductivity at the same time. The reason may be that the sulfonic acid group of sodium dodecylbenzenesulfonate in the comparative hollow glass microspheres inhibits the polymerization of vinyl silicone oil by the free radical curing agent, resulting in incomplete curing.

[0125] Obviously, the above-mentioned embodiments of the present invention are only examples for clearly explaining the present invention, and are not intended to limit the embodiments of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A preparation method of silver-coated hollow glass microspheres, characterized in that, It includes the following steps: S1. Degrease the hollow glass microspheres to obtain pretreated hollow glass microspheres; S2. Mix the pretreated hollow glass microspheres, polyacrylic resin, silver ammonia solution, reducing agent and alkali agent to form a reaction solution, and carry out a reduction reaction to obtain the silver-coated hollow glass microspheres.

2. The preparation method according to claim 1, characterized in that, In step S1, after the degreasing treatment, it further includes an acid treatment step.

3. The preparation method according to claim 1, wherein In step S2, the mass ratio of the polyacrylic resin to the silver element in the reaction solution is (1×10 -6 ~1×10 -5 ):

1.

4. The preparation method according to claim 1, wherein In step S2, the mass ratio of the pretreated hollow glass microspheres to the polyacrylic resin in the reaction solution is 1:(1×10 -7 ~1×10 -6 ).

5. The preparation method according to claim 4, characterized in that, In step S2, the mass concentration of the polyacrylic resin in the reaction solution is 1×10 -5 ~1×10 -4 .

6. The preparation method according to claim 1, wherein In step S2, the reaction time of the reduction reaction is 0.1 - 1 h.

7. The preparation method according to claim 1, wherein In step S2, the silver content in the silver-coated hollow glass microspheres is 1 - 20 wt.%.

8. A silver-coated hollow glass microsphere, characterized in that, It is prepared by the preparation method according to any one of claims 1 - 7.

9. Use of the silver-coated hollow glass microspheres according to claim 8 in the preparation of an organosilicon thermally conductive potting adhesive.

10. A silicone thermal conductive potting adhesive, characterized in that, It includes components A and B with a mass ratio of 1:(0.8 - 1.2); by weight, component A includes the following components: 50 - 80 parts of vinyl-terminated silicone oil, 5 - 30 parts of the silver-coated hollow glass microspheres according to claim 8; component B includes the following components: 50 - 80 parts of vinyl-terminated silicone oil, 5 - 30 parts of the silver-coated hollow glass microspheres according to claim 8, and 1 - 10 parts of a free radical curing agent.

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