Modified hollow glass bead, preparation method and organic silicon pouring sealant

Abstract

The invention discloses modified hollow glass beads, which are prepared from the following raw materials: hollow glass beads, a solvent, an alkaline pretreatment solution, an acid-base regulator and a silane coupling agent, and the silane coupling agent is a non-reactive long-chain alkyl silane coupling agent. The non-reactive long-chain alkyl silane coupling agent is adopted to modify the surfaces of the hollow glass beads, so that the compatibility and dispersity of the hollow glass beads in an organic silicon system are remarkably improved, and the curing reaction of an organic silicon polymer is not influenced. A non-reactive long-chain alkyl silane coupling agent is selected, and a long and flexible molecular chain can be inserted between polymer macromolecular chains, so that the intermolecular acting force is weakened, the movement capability of a chain segment is improved, the hardness and modulus of the material are reduced, and the flexibility and the elongation are improved.

Description

Technical Field

[0001] This invention relates to the field of adhesives, specifically to a modified hollow glass microsphere, its preparation method, and an organosilicon potting compound. Background Technology

[0002] Hollow glass microspheres, as a lightweight filler, possess advantages such as low density, low thermal conductivity, and good chemical stability, and are widely used in silicone potting compounds. However, the significant polarity difference between hollow glass microspheres and silicone resins leads to poor compatibility, causing problems such as delamination and sedimentation in the potting compound system, severely affecting the mechanical properties and stability of the potting compound. Currently, aminosilane coupling agents or epoxy coupling agents are used to modify hollow glass microspheres; however, these coupling agents contain active groups that can react with the polymer matrix, resulting in problems such as slower curing speed, catalyst deactivation, and even incomplete curing during the silicone potting compound curing process. Therefore, developing a novel modified hollow glass microsphere to solve the compatibility problem with silicone potting compounds is crucial.

[0003] Chinese invention patent application CN117843890A discloses a surface-modified hollow glass microsphere and its preparation method. The method involves first alkaline etching the hollow glass microspheres, then adding a silane coupling agent to the solution, followed by mixing with an amide monomer containing a carbon-carbon double bond and a phosphate ester monomer containing a carbon-carbon double bond. An initiator is then added to initiate the reaction, resulting in surface-modified hollow glass microspheres. The surface-modified hollow glass microspheres possess an active double bond structure, which may affect the curing of silicone resins. Chinese invention patent application CN121182447A discloses a silicone potting compound, its preparation method, and its application. The raw materials include spherical alumina treated with a surface treatment agent and hollow glass microspheres. However, the amount of hollow glass microspheres added is low, and the compatibility issue with the silicone potting compound is not resolved. Summary of the Invention

[0004] In order to develop a novel modified hollow glass microsphere to solve the compatibility problem with silicone potting compound, the first aspect of the present invention provides a modified hollow glass microsphere, the raw materials for preparation including hollow glass microsphere, solvent, alkaline pretreatment solution, acid-base adjuster and silane coupling agent, wherein the silane coupling agent is a non-reactive long-chain alkylsilane coupling agent.

[0005] This invention employs a non-reactive long-chain alkylsilane coupling agent to modify hollow glass microspheres, significantly improving the compatibility and dispersibility of inorganic materials in organic phases and preventing aggregation. When the silane in the long-chain silane hydrolyzes, its silanol ends react with the hydroxyl groups on the substrate surface to form strong Si-O-substrate covalent bonds. This causes the long-chain alkyl groups to be densely and directionally arranged on the substrate surface like "molecular brushes," forming a low surface energy monolayer. This layer effectively prevents water molecule penetration and wetting, promoting dispersion in the organic phase. The long, flexible molecular chains can insert into the polymer macromolecular chains, weakening intermolecular forces, increasing chain mobility, reducing material hardness and modulus, and increasing flexibility and elongation.

[0006] Unlike amino and epoxy silane coupling agents, long-chain alkyl silane coupling agents are non-reactive long-chain alkyl groups that do not chemically react with the polymer matrix. They improve the interface through the entanglement and physical compatibility of their long-chain structure with the polymer chain. In contrast, amino and epoxy silanes contain groups that can react with the polymer matrix, which may lead to slower curing during the curing process, catalyst deactivation, failure to cure the polymer, and increased polymer hardness.

[0007] As one embodiment, the non-reactive long-chain alkylsilane coupling agent includes at least one of octyltrimethoxysilane, hexadecyltrimethoxysilane, and octadecyltrimethoxysilane.

[0008] As one embodiment, the alkaline pretreatment solution is a 1-5 wt% NaOH aqueous solution.

[0009] In one embodiment, the hollow glass microspheres have an average particle size of 10-30 μm.

[0010] In one embodiment, the amount of the non-reactive long-chain alkylsilane coupling agent added is 1-5% of the mass of the hollow glass microspheres.

[0011] In one embodiment, the solvent includes deionized water and an alcohol solvent, wherein the alcohol solvent includes at least one of ethanol, isopropanol, n-propanol, n-butanol, tert-butanol, or ethylene glycol.

[0012] In one embodiment, the acid-base regulator is glacial acetic acid.

[0013] As one implementation method, the raw materials prepared by weight include 10-30 parts of hollow glass microspheres, 40-60 parts of solvent, and 150-250 parts of alkaline pretreatment solution.

[0014] A second aspect of the present invention provides a method for preparing modified hollow glass microspheres, comprising the following steps: The dried hollow glass microspheres were placed in an alkaline pretreatment solution and stirred for 1-5 hours, then washed until neutral, and dried to obtain pretreated hollow glass microspheres. The pH of the solvent was adjusted with an acid-base adjuster, and pretreated hollow glass microspheres and silane coupling agent were added. The mixture was stirred at the reaction temperature for 3-8 hours, washed, and dried to obtain modified hollow glass microspheres.

[0015] In one embodiment, the reaction temperature is 40-80°C; the pH is 3-5.5.

[0016] A third aspect of the present invention provides an organosilicon potting compound comprising the modified hollow glass microspheres described above.

[0017] In one embodiment, the raw materials include component A and component B. The modified hollow glass microspheres include modified hollow glass microspheres A and modified hollow glass microspheres B. Component A includes vinyl silicone oil A, aluminum hydroxide A, modified hollow glass microspheres A, and a catalyst. Component B includes vinyl silicone oil B, hydrogen-containing silicone oil, aluminum hydroxide B, modified hollow glass microspheres B, and an inhibitor.

[0018] In one embodiment, component A, by weight, comprises 5-15 parts vinyl silicone oil A, 7.3-8.3 parts aluminum hydroxide A, 0.7-1.7 parts modified hollow glass microspheres A, and 0.01-0.05 parts catalyst; component B comprises 5-15 parts vinyl silicone oil B, 0.5-1.5 parts hydrogen-containing silicone oil, 7.3-8.3 parts aluminum hydroxide B, 0.7-1.7 parts modified hollow glass microspheres B, and 0.03-0.09 parts inhibitor.

[0019] In one embodiment, both vinyl silicone oil A and vinyl silicone oil B have a viscosity of 50-150 cP at 25°C.

[0020] In one embodiment, the particle size of both aluminum hydroxide A and aluminum hydroxide B is 1-20 μm.

[0021] In one embodiment, the hydrogen-containing silicone oil includes high-hydrogen-content silicone oil and low-hydrogen-content silicone oil, wherein the high-hydrogen-content silicone oil has a hydrogen content of 1.58-1.62 wt%; the low-hydrogen-content silicone oil has a hydrogen content of 0.33-0.37 wt%; and the weight ratio of the low-hydrogen-content silicone oil to the high-hydrogen-content silicone oil is (0.7-0.9):(0.1-0.3).

[0022] In one embodiment, the weight ratio of aluminum hydroxide A to modified hollow glass microspheres A is the same as the weight ratio of aluminum hydroxide B to modified hollow glass microspheres B, which is (7.3-8.3):(0.7-1.7).

[0023] In one embodiment, the catalyst is a cassiterite catalyst, wherein the platinum content in the cassiterite catalyst is 2000-4000 ppm; or the platinum content in the cassiterite catalyst is 3000 ppm.

[0024] In one embodiment, the inhibitor is 1-ethynyl-1-cyclohexanol.

[0025] As one embodiment, the preparation method of the silicone potting compound includes the following steps: Vinyl silicone oil A, aluminum hydroxide A, modified hollow glass microspheres A and catalyst were stirred at 800-1500 r / min for 1-2 h to obtain component A; Vinyl silicone oil B, hydrogen-containing silicone oil, aluminum hydroxide B, modified hollow glass microspheres B, and inhibitor were stirred at 800-1500 r / min for 1-2 h to obtain component B. Mixing component A and component B yields an organosilicon potting compound.

[0026] In one embodiment, the mass ratio of component A to component B is 1:(1-3).

[0027] In one embodiment, the mass ratio of component A to component B is 1:1.

[0028] Compared with the prior art, the present invention has the following beneficial effects: (1) The modified hollow glass microspheres of the present invention are pretreated with NaOH aqueous solution to corrode the smooth surface of the hollow glass microspheres and graft -OH on the surface to increase the hydroxyl content of the surface and increase the bonding strength between the hollow glass microspheres and the non-reactive long-chain alkylsilane coupling agent.

[0029] (2) The modified hollow glass microspheres of the present invention use a non-reactive long-chain alkylsilane coupling agent to modify the surface of the hollow glass microspheres, which significantly improves the compatibility and dispersibility of the hollow glass microspheres in the organosilicon system, and does not affect the curing reaction of the organosilicon polymer.

[0030] (3) The modified hollow glass microspheres described in this invention are applied to organosilicon potting compounds. Non-reactive long-chain alkylsilane coupling agents are selected. The long and flexible molecular chains can be inserted between polymer macromolecular chains, weakening the intermolecular forces, increasing the mobility of chain segments, reducing the hardness and modulus of the material, and increasing the flexibility and elongation.

[0031] (4) The modified hollow glass microspheres of the present invention use a reaction temperature of 40-80℃ and a pH of 3-5.5 during the modification process, which can optimize the hydrolysis and condensation reaction balance of the coupling agent, so that the modified hollow glass microspheres can ensure a sufficient reaction rate and avoid side reactions.

[0032] (5) When the modified hollow glass microspheres described in this invention are applied to silicone potting compound, by controlling the weight ratio of low hydrogen content silicone oil to high hydrogen content silicone oil to be (0.7-0.9):(0.1-0.3), the silicone potting compound can have lower hardness and excellent tensile properties. Detailed Implementation

[0033] Example 1 A modified hollow glass microsphere is prepared by means of 20g hollow glass microspheres, 50mL solvent, 200mL alkaline pretreatment solution, acid-base regulator and 0.2g silane coupling agent.

[0034] The hollow glass microspheres have a particle size of 10-30 μm and were purchased from Zhengzhou Shenglait Hollow Microsphere New Material Co., Ltd., with the grade HS60.

[0035] The solvent includes 40 mL of ethanol and 10 mL of deionized water.

[0036] The alkaline pretreatment solution is a 3 wt% NaOH aqueous solution.

[0037] The pH adjuster is glacial acetic acid, used to adjust the pH to 3.

[0038] The silane coupling agent is octyltrimethoxysilane.

[0039] A method for preparing modified hollow glass microspheres includes the following steps: Hollow glass microspheres dried at 80℃ for 6 hours were placed in an alkaline pretreatment solution and stirred for 3 hours. They were then filtered under reduced pressure, washed with pure water until neutral, and dried at 80℃ for 10 hours to obtain pretreated hollow glass microspheres. The solvent was adjusted to pH 3 with an acid-base adjuster, and pretreated hollow glass microspheres and silane coupling agent were added. The mixture was stirred at 40°C for 6 hours, filtered under reduced pressure, washed with anhydrous ethanol, and dried at 80°C for 10 hours to obtain modified hollow glass microspheres.

[0040] An organosilicon potting compound, wherein component A comprises 10 parts by weight of vinyl silicone oil A, 8 parts of aluminum hydroxide A, 1 part of modified hollow glass microspheres A, and 0.04 parts of catalyst; and component B comprises 9 parts of vinyl silicone oil B, 1 part of hydrogen-containing silicone oil, 8 parts of aluminum hydroxide B, 1 part of modified hollow glass microspheres B, and 0.06 parts of inhibitor.

[0041] The vinyl silicone oil A and vinyl silicone oil B both have a viscosity of 100 cP at 25°C and were purchased from Dongguan Huayue Technology Co., Ltd., with the brand name HY100.

[0042] The aluminum hydroxide A and aluminum hydroxide B have a particle size of 1-20 μm and were purchased from Hefei Zhongke Flame Retardant New Materials Co., Ltd.

[0043] Both the modified hollow glass microspheres A and B are modified hollow glass microspheres prepared as described above.

[0044] The catalyst is a cassiterite catalyst with a platinum content of 3000 ppm.

[0045] The hydrogen-containing silicone oil includes low-hydrogen-content silicone oil and high-hydrogen-content silicone oil, with a weight ratio of 0.8:0.2; the high-hydrogen-content silicone oil has a hydrogen content of 1.58-1.62%, purchased from Foshan Huagu Organosilicon Co., Ltd., with the grade V202-160; the low-hydrogen-content silicone oil has a hydrogen content of 0.33-0.37%, purchased from Foshan Huagu Organosilicon Co., Ltd., with the grade V202-035.

[0046] The inhibitor is 1-ethynyl-1-cyclohexanol.

[0047] The preparation method of the organosilicon potting compound includes the following steps: Vinyl silicone oil A, aluminum hydroxide A, modified hollow glass microspheres A, and catalyst were stirred at 1000 r / min for 1.2 h to obtain component A; Vinyl silicone oil B, hydrogen-containing silicone oil, aluminum hydroxide B, modified hollow glass microspheres B, and inhibitor were stirred at 1000 r / min for 1.5 h to obtain component B. Mixing component A and component B yields an organosilicon potting compound.

[0048] The mass ratio of component A to component B is 1:1.

[0049] Example 2 A modified hollow glass microsphere and its preparation method are described. The specific implementation method is the same as in Example 1, except that the reaction temperature is 60℃.

[0050] An organosilicon potting compound, the specific implementation method is the same as in Example 1.

[0051] Example 3 A modified hollow glass microsphere and its preparation method are described. The specific implementation method is the same as in Example 1, except that the reaction temperature is 80℃.

[0052] An organosilicon potting compound, the specific implementation method is the same as in Example 1.

[0053] Example 4 A modified hollow glass microsphere and its preparation method are described. The specific implementation method is the same as in Example 1, except that the pH is 4.

[0054] An organosilicon potting compound, the specific implementation method is the same as in Example 1.

[0055] Example 5 A modified hollow glass microsphere and its preparation method are described. The specific implementation method is the same as that in Example 4, except that the amount of silane coupling agent added is 3% of the mass of the hollow glass microsphere.

[0056] An organosilicon potting compound, the specific implementation method is the same as in Example 1.

[0057] Example 6 A modified hollow glass microsphere and its preparation method are described. The specific implementation method is the same as in Example 5, except that the pH is 5.5.

[0058] An organosilicon potting compound, the specific implementation method is the same as in Example 1.

[0059] Example 7 A modified hollow glass microsphere and its preparation method are described. The specific implementation method is the same as that in Example 4, except that the amount of silane coupling agent added is 5% of the mass of the hollow glass microsphere.

[0060] An organosilicon potting compound, the specific implementation method is the same as in Example 1.

[0061] Example 8 A modified hollow glass microsphere and its preparation method are described. The specific implementation method is the same as that in Example 5, except that the solvent includes 40 mL of isopropanol and 10 mL of deionized water.

[0062] An organosilicon potting compound, the specific implementation method is the same as in Example 1.

[0063] Example 9 A modified hollow glass microsphere and its preparation method are disclosed. The specific implementation method is the same as in Example 5, except that the preparation method of the modified hollow glass microsphere includes the following steps: Hollow glass microspheres dried at 80℃ for 6 hours were placed in an alkaline pretreatment solution and stirred for 3 hours. They were then filtered under reduced pressure, washed with pure water until neutral, and dried at 80℃ for 10 hours to obtain pretreated hollow glass microspheres. The pH of the solvent was adjusted to 3 using an acid-base adjuster. Pretreated hollow glass microspheres were added, and silane coupling agent was added dropwise (dropping rate of 2s / drop). The mixture was stirred at 40℃ for 6 hours, filtered under reduced pressure, washed with anhydrous ethanol, and dried at 80℃ for 10 hours to obtain modified hollow glass microspheres.

[0064] An organosilicon potting compound, the specific implementation method is the same as in Example 1.

[0065] Example 10 A modified hollow glass microsphere and its preparation method are described. The specific implementation method is the same as in Example 5, except that the silane coupling agent is hexadecyltrimethoxysilane.

[0066] An organosilicon potting compound, the specific implementation method is the same as in Example 1.

[0067] Example 11 A modified hollow glass microsphere and its preparation method are described. The specific implementation method is the same as in Example 5, except that the silane coupling agent is octadecyltrimethoxysilane.

[0068] An organosilicon potting compound, the specific implementation method is the same as in Example 1.

[0069] Example 12 A modified hollow glass microsphere and its preparation method are described. The specific implementation method is the same as that in Example 5, except that the silane coupling agent is a combination of γ-aminopropyltriethoxysilane (KH550) and γ-glycidoxypropyltrimethoxysilane (KH560) in a weight ratio of 1:2.

[0070] An organosilicon potting compound, the specific implementation method is the same as in Example 1.

[0071] Comparative Example 1 An organosilicon potting compound, the specific implementation method is the same as in Example 1, except that modified hollow glass microspheres A and modified hollow glass microspheres B are both replaced with hollow glass microspheres.

[0072] Comparative Example 2 An organosilicon potting compound, the specific embodiment of which is the same as Comparative Example 1, except that the hydrogen-containing silicone oil includes low-hydrogen-content silicone oil and high-hydrogen-content silicone oil, with a weight ratio of 0.9:0.1.

[0073] Comparative Example 3 An organosilicon potting compound, the specific embodiment of which is the same as Comparative Example 1, except that the hydrogen-containing silicone oil includes low-hydrogen-content silicone oil and high-hydrogen-content silicone oil, with a weight ratio of 0.7:0.3.

[0074] Comparative Example 4 An organosilicon potting compound, the specific implementation of which is the same as Comparative Example 2, except that hollow glass microspheres are replaced with pretreated hollow glass microspheres.

[0075] Comparative Example 5 A modified hollow glass microsphere and its preparation method are described. The specific implementation method is the same as that in Example 1, except that the amount of silane coupling agent added is 0.1% of the mass of the hollow glass microsphere.

[0076] An organosilicon potting compound, the specific implementation method is the same as in Example 1.

[0077] Comparative Example 6 A modified hollow glass microsphere and its preparation method are described. The specific implementation method is the same as that in Example 1, except that the amount of silane coupling agent added is 0.5% of the mass of the hollow glass microsphere.

[0078] An organosilicon potting compound, the specific implementation method is the same as in Example 1.

[0079] Comparative Example 7 A modified hollow glass microsphere and its preparation method are disclosed. The specific implementation method is the same as that in Example 5, except that the organosilicon potting compound comprises, by weight, 10 parts of vinyl silicone oil A, 8.5 parts of aluminum hydroxide A, 0.5 parts of modified hollow glass microsphere A, and 0.04 parts of catalyst; and 9 parts of vinyl silicone oil B, 1 part of hydrogen-containing silicone oil, 8.5 parts of aluminum hydroxide B, 0.5 parts of modified hollow glass microsphere B, and 0.06 parts of inhibitor.

[0080] The remaining implementation methods are the same as in Example 5.

[0081] Comparative Example 8 A modified hollow glass microsphere and its preparation method are disclosed. The specific implementation method is the same as that in Example 5, except that the organosilicon potting compound, by weight, comprises: component A: 10 parts vinyl silicone oil A, 7 parts aluminum hydroxide A, 2 parts modified hollow glass microspheres A, and 0.04 parts catalyst; component B: 9 parts vinyl silicone oil B, 1 part hydrogen-containing silicone oil, 7 parts aluminum hydroxide B, 2 parts modified hollow glass microspheres B, and 0.06 parts inhibitor.

[0082] The remaining implementation methods are the same as in Example 5.

[0083] Comparative Example 9 A modified hollow glass microsphere and its preparation method are described. The specific implementation method is the same as that in Example 5, except that the silane coupling agent is γ-aminopropyltriethoxysilane (KH550).

[0084] An organosilicon potting compound, the specific implementation method is the same as in Example 5.

[0085] Comparative Example 10 A modified hollow glass microsphere and its preparation method are described. The specific implementation method is the same as that in Example 5, except that the silane coupling agent is γ-glycidoxypropyltrimethoxysilane (KH560).

[0086] An organosilicon potting compound, the specific implementation method is the same as in Example 5.

[0087] Comparative Example 11 A modified hollow glass microsphere and its preparation method are described. The specific implementation method is the same as that in Example 5, except that octyltrimethoxysilane is replaced with isopropyltris(dioctylpyrophosphate)titanate, and the pH is 5.

[0088] Comparative Example 12 A modified hollow glass microsphere and its preparation method are described. The specific implementation method is the same as in Example 5, except that octyltrimethoxysilane is replaced with oxyacetate bis(dioctyl phosphate) titanate.

[0089] Comparative Example 13 A modified hollow glass microsphere and its preparation method are described. The specific implementation method is the same as in Example 5, except that octyltrimethoxysilane is replaced with isopropyltriisostearate titanate.

[0090] Performance testing 1. Viscosity: The viscosity of the examples and comparative examples was tested using a rotational viscometer, according to GB / T 2794-2013, at room temperature of 25°C, using a rotor of size SC4-27.

[0091] 2. Hardness: The hardness of the samples was tested using a Shore A hardness tester, according to GB / T 531.1-2008. The sample size was 2 cm × 2 cm × 0.6 cm. The hardness of the test examples and comparative examples was also tested.

[0092] 3. Tensile strength and elongation at break: Referring to GB / T 528-2009 standard, the performance of the examples and comparative examples was tested using a universal testing machine. The samples were cut into dumbbell shapes according to the test standard. The test temperature was 25℃, the tensile rate was 200 mm / min, and each sample was tested five times.

[0093] The test results are shown in Table 1.

[0094] Table 1

Claims

1. A modified hollow glass microsphere, characterized in that, The raw materials for preparation include hollow glass microspheres, solvent, alkaline pretreatment solution, acid-base regulator and silane coupling agent, wherein the silane coupling agent is a non-reactive long-chain alkylsilane coupling agent.

2. The modified hollow glass microspheres according to claim 1, characterized in that, The non-reactive long-chain alkylsilane coupling agent includes at least one of octyltrimethoxysilane, hexadecyltrimethoxysilane, and octadecyltrimethoxysilane.

3. The modified hollow glass microspheres according to claim 1, characterized in that, The amount of the non-reactive long-chain alkylsilane coupling agent added is 1-5% of the mass of the hollow glass microspheres.

4. The modified hollow glass microspheres according to claim 1, characterized in that, The solvent includes deionized water and an alcohol solvent, wherein the alcohol solvent includes at least one of ethanol, isopropanol, n-propanol, n-butanol, tert-butanol, or ethylene glycol.

5. A method for preparing modified hollow glass microspheres according to any one of claims 1-4, characterized in that, Includes the following steps: The dried hollow glass microspheres were placed in an alkaline pretreatment solution and stirred for 1-5 hours, then washed until neutral, and dried to obtain pretreated hollow glass microspheres. The pH of the solvent was adjusted with an acid-base adjuster, and pretreated hollow glass microspheres and silane coupling agent were added. The mixture was stirred at the reaction temperature for 3-8 hours, washed, and dried to obtain modified hollow glass microspheres.

6. The method for preparing modified hollow glass microspheres according to claim 5, characterized in that, The reaction temperature is 40-80℃; the pH is 3-5.

5.

7. A silicone potting compound, characterized in that, Including the modified hollow glass microspheres as described in any one of claims 1-4.

8. The silicone potting compound according to claim 7, characterized in that, The raw materials for preparation include component A and component B. The modified hollow glass microspheres include modified hollow glass microspheres A and modified hollow glass microspheres B. Component A includes vinyl silicone oil A, aluminum hydroxide A, modified hollow glass microspheres A and a catalyst. Component B includes vinyl silicone oil B, hydrogen-containing silicone oil, aluminum hydroxide B, modified hollow glass microspheres B and an inhibitor.

9. The silicone potting compound according to claim 8, characterized in that, The hydrogen-containing silicone oil includes high-hydrogen-content silicone oil and low-hydrogen-content silicone oil. The high-hydrogen-content silicone oil has a hydrogen content of 1.58-1.62 wt%; the low-hydrogen-content silicone oil has a hydrogen content of 0.33-0.37 wt%; and the weight ratio of the low-hydrogen-content silicone oil to the high-hydrogen-content silicone oil is (0.7-0.9):(0.1-0.3).

10. The silicone potting compound according to claim 8, characterized in that, The weight ratio of aluminum hydroxide A to modified hollow glass microspheres A is the same as the weight ratio of aluminum hydroxide B to modified hollow glass microspheres B, which is (7.3-8.3):(0.7-1.7).

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