A combined filler modified silicone paste and a preparation method thereof

Abstract

The application provides a combined filler modified silicone paste and a preparation method thereof. In dimethyl silicone oil, long-chain alkyl siloxane is added, silica aerogel, precipitated white carbon black and a catalyst are stirred and added, and wet air is intermittently introduced for stirring to perform a first mixing reaction; then, hydroxyl silicone oil is added for stirring to perform a second mixing reaction; after being heated, a third mixing reaction is continuously performed under vacuum condition through stirring; heating is stopped, and cooling is performed to obtain the combined filler modified silicone paste. In the application, the precipitated white carbon black and the silica aerogel filler are dispersed in different particle size scales in the dimethyl silicone oil as a dispersion medium phase; under the action of the catalyst, condensation reactions occur between the filler surface -OH and the long-chain alkyl siloxane and the hydroxyl silicone oil, and a single long tail, double long tail, multiple long tail or combined molecular structure mode is generated; in addition, due to the three-dimensional space accumulation of different size particles, the prepared silicone paste is easy to emulsify, easy to compound, and has excellent foam inhibition performance.

Description

Technical Field

[0001] This invention relates to the field of defoamers, specifically to a combined filler-modified silicone paste and its preparation method. Background Technology

[0002] There are many types of defoamers, mainly classified by composition as non-silicone, silicone, and silicone compound systems, each with its own advantages and disadvantages in different application scenarios. Organosilicon defoamers come in two types: one is pure silicone oil or with added additives for oily systems; the other is silicone oil modified with silica to form silicone paste, which is then combined with emulsifiers, stabilizers, bactericides, and diluents to prepare emulsion or solution-type defoamers. In the actual production and application of defoamers, silicone paste is the core of the defoamer, essentially dominating its main defoaming and foam-suppressing properties.

[0003] CN 111171321 B describes a process where 1-dodecene and hydrogen-containing silicone oil are pre-reacted at 65–95°C for 0.5–4 h under platinum catalyst. Fumed silica with a specific surface area of ​​100–250 m² / g is then added, and the reaction is carried out at 110–150°C for 1–5 h to obtain a long-chain alkyl silicone oil-based silicone paste. 10% of the prepared silicone paste, 81% of No. 26 white oil, 6% of emulsifier (Span 80: Tween 80 = 5:1), and 3% of PPG 800 are mixed and heated until homogeneous to obtain a defoamer. The defoaming time is 15–30 s, and the foam suppression time is 10–25 min. The above method utilizes the principles of C=C, Si-H addition polymerization, and the condensation of Si-H and Si-OH on the surface of fumed silica to co-modify fumed silica. After high-temperature mixing and reaction treatment, silicone paste is obtained. The resulting silicone paste is then formulated into a composite defoamer, but its defoaming and foam suppression performance is limited.

[0004] This invention develops a novel silicone paste with a combined filler and long-chain alkyl grafted at room temperature. The filler with different particle size is optimized in distribution and surface active sites Si-OH. Long-chain alkyl siloxanes are dispersed in inert silicone oil and grafted onto the filler surface under the presence of a catalyst. Further heating and mixing reaction generates single-tailed, double-tailed, multi-tailed, or combined molecular structures. This silicone paste is easy to emulsify and compound, and has excellent defoaming and antifoaming properties. Summary of the Invention

[0005] To provide excellent defoaming and foam-suppressing performance and a wide range of applications, this patent provides a novel silicone paste with a combined filler and a room-temperature grafted long-chain alkyl group, as well as its preparation method.

[0006] The objective of this invention is achieved through the following technical solution: A composite filler silicone paste and its preparation method, comprising the following steps: In dimethyl silicone oil, long-chain alkylsiloxanes are added, followed by the addition of silica aerogel, precipitated silica, and catalyst. Moist air is intermittently introduced and the mixture is stirred for 1-6 hours. Then, hydroxyl silicone oil is added and the mixture is stirred for 0.5-2 hours. The temperature is then raised to 60-250℃, a vacuum (50-5000Pa) is applied, and stirring continues for 2-10 hours. Finally, heating is stopped and the mixture is cooled to obtain a composite filler-modified silicone paste.

[0007] The dimethyl silicone oil comprises a combination of one or more dimethyl silicone oils with viscosities ranging from 50 cSt to 200,000 mPa·s, accounting for 65-95% of the viscous silicone paste.

[0008] The long-chain alkylsiloxane comprises one or more combinations of octylmethyldimethoxysilane, octylmethyldiethoxysilane, dodecylmethyldimethoxysilane, dodecylmethyldiethoxysilane, hexadecylmethyldimethoxysilane, hexadecylmethyldiethoxysilane, octadecylmethyldimethoxysilane, and octadecylmethyldiethoxysilane, accounting for 0.5-10% of the viscous silicone paste, preferably 1-5%.

[0009] The silica aerogel has a BET ratio of 500-1200 m² / g.

[0010] The precipitated silica has a BET specific gravity of 80-400 m² / g.

[0011] The ratio of silica aerogel to precipitated silica is 1:5 to 5:1, and the sum of the two constitutes 3-25% of the viscous silicone paste.

[0012] The catalyst comprises one or more combinations of organotin compounds, organotitanium compounds, modified organotin, and modified organotitanium, accounting for 0.05-5% of the viscous silicone paste, preferably 0.2-3%. The organotin compounds include dibutyltin dilaurate, dibutyltin diacetate, di(dodecylthio)dioctyltin, etc.; the organotitanium compounds include tetrabutyl titanate, tetraisopropyl titanate, tetramethylphenol titanium, etc.; the modified organotin compounds include anhydrous stannous chloride and organotin composite systems and trinuclear organostannous metal catalysts, etc.; the modified organotitanium compounds include porous supported silica titanium catalysts such as TiOC@SiO2 catalysts, chelated nitrogen-titanium catalysts, chelated phosphorus-titanium catalysts, cobalt-titanium composite catalysts, etc.

[0013] The intermittent introduction of humid air includes humid air in the form of water vapor generated from tap water, heated distilled water, or water vapor carried out by nitrogen gas passing through water bodies. The humid air primarily helps the hydrolysis of silanes such as long-chain alkylsiloxanes, increasing the reaction rate.

[0014] The long-chain alkylsiloxane accounts for 1% to 5% of the mass percentage of the combined filler silicone paste; the catalyst accounts for 0.2% to 3% of the mass percentage of the combined filler silicone paste.

[0015] The hydroxyl silicone oil comprises medium and low double-ended hydroxyl silicone oil or single-ended hydroxyl silicone oil or a combination of double-ended hydroxyl silicone oil and single-ended hydroxyl silicone oil with a viscosity of 10 cSt to 1000 cSt and a hydroxyl content of 0.1% to 10.0%, accounting for 1-15% of the viscous silicone paste.

[0016] The present invention also provides a composite filler silicone paste, which is prepared by the preparation method described herein.

[0017] In some preferred embodiments, the silicone paste reaction formula and product structural formula include the following:

[0018] Formula I Depending on the reactants, the reaction can also be expressed as follows:

[0019] Formula II Alternatively, given the above reactants, the reaction formula may also include the following:

[0020] Formula III The R mentioned 1 =CH3,CH2CH3;R 2 =C8~C 18 Alkyl groups.

[0021] Equations I, II, and III may be only Equation I or Equation II; when both Equations I and II exist, Equation III will also exist.

[0022] In the composite filler-modified silicone paste, the particle morphology distribution is roughly as follows: .

[0023] In the combined filler silicone paste, the filler surface is grafted with molecular structures of single long tail, double long tail, multiple long tail or combination thereof through condensation reaction, and fillers of different particle sizes form a three-dimensional spatial stacking structure.

[0024] When the combined filler silicone paste is used to prepare defoamers, its defoaming time is 2 to 8 seconds and its foam suppression time is 50 to 310 minutes.

[0025] The dimethyl silicone oil is a single viscosity specification or a combination of multiple viscosity specifications.

[0026] The present invention also provides an antifoaming agent comprising the aforementioned combined filler silicone paste, as well as an emulsifier, a thickener, and a diluent.

[0027] The reaction formulas and morphological distributions of the novel silicone paste containing a combined filler and grafted long-chain alkyl groups described in this application are shown in Formulas I, II, and III, respectively (the structural formulas of the embodiments can be obtained from the following reaction formulas):

[0028] Formula I

[0029] Formula II

[0030]

[0031] Formula III R 1 =CH3,CH2CH3;R 2 =C8~C 18 Alkyl groups.

[0032] Through the above technical solutions, the present invention has the following technical effects: Using dimethyl silicone oil as the dispersion medium, precipitated silica and silica aerogel fillers of different particle sizes are dispersed. Under the action of a catalyst, the -OH on the surface of the filler undergoes a condensation reaction with long-chain alkylsiloxanes and hydroxyl silicone oil, generating single-tailed, double-tailed, multi-tailed, or combined molecular structures. In addition, due to the three-dimensional spatial stacking of different particle sizes, the prepared silicone paste is easy to emulsify and compound, and has excellent defoaming and antifoaming properties. Detailed Implementation

[0033] Example 1 Add 8.45 kg of KM-50 dimethyl silicone oil (Hubei Xingfa Chemical Group Co., Ltd.) to a disperser, start stirring and add 0.2 kg of hexadecylmethyldimethoxysilane (Hubei Jianghan New Material Co., Ltd.), continue stirring and add 0.2 kg of silica aerogel (Hubei Xingrui Silicon Materials Co., Ltd., silica aerogel 20) and 0.8 kg of precipitated silica HL-915 (Fujian Sanming Heli New Material Technology Co., Ltd.), stir and mix evenly, add 0.05 kg of D80 dibutyltin dilaurate catalyst (Hubei Xinlantian New Material Co., Ltd.), intermittently pass in 100% humid air generated by distilled water, add 0.3 kg of α,ω-dihydroxypolydimethylsiloxane (WS-62M, Wacker Chemie (China) Co., Ltd., chain segment n=30-45), stir and mix at room temperature for 2 h, raise the temperature to 85-90℃, turn on the vacuum and maintain 500±50 Pa, continue stirring for 5 h, stop heating and cool, to obtain composite filler modified silicone paste A1. In Example 1, Formula I-1, Formula II-1, and Formula III-1 are as follows:

[0034] Formula I-1

[0035] Formula II-1

[0036] Formula III-1 Example 2 Add 8.45 kg of KM-500 dimethyl silicone oil (Hubei Xingfa Chemical Group Co., Ltd.) to a disperser, start stirring and add 0.2 kg of hexadecylmethyldimethoxysilane (Hubei Jianghan New Material Co., Ltd.), continue stirring and add 0.2 kg of silica aerogel (Hubei Xingrui Silicon Material Co., Ltd., silica aerogel 20) and 0.8 kg of precipitated silica HL-915 (Fujian Sanming Heli New Material Technology Co., Ltd.), stir and mix evenly, add 0.05 kg of D80 dibutyltin dilaurate catalyst (Hubei Xinlantian New Material Co., Ltd.), intermittently pass 100% humid air generated by distilled water, add 0.3 kg of α,ω-dihydroxypolydimethylsiloxane (WS-62M, Wacker Chemie (China) Co., Ltd.), stir and mix at room temperature for 2 h, raise the temperature to 85-90℃, turn on the vacuum and maintain 500±50 Pa, continue stirring for 5 h, stop heating and cool, to obtain composite filler modified silicone paste A2.

[0037] Example 3 Add 8.45 kg of KM-60000 dimethyl silicone oil (Hubei Xingfa Chemical Group Co., Ltd.) to a disperser, start stirring and add 2 kg of hexadecylmethyldimethoxysilane (Hubei Jianghan New Material Co., Ltd.), continue stirring and add 0.2 kg of silica aerogel (Hubei Xingrui Silicon Material Co., Ltd., silica aerogel 20) and 0.8 kg of precipitated silica HL-915 (Fujian Sanming Heli New Material Technology Co., Ltd.), stir and mix evenly, add 0.05 kg of D80 dibutyltin dilaurate catalyst (Hubei Xinlantian New Material Co., Ltd.), intermittently pass 100% humid air generated by distilled water, add 0.3 kg of α,ω-dihydroxypolydimethylsiloxane (WS-62M, Wacker Chemie (China) Co., Ltd.), stir and mix at room temperature for 2 h, raise the temperature to 85-90℃, turn on the vacuum and maintain 500±50 Pa, continue stirring for 5 h, stop heating and cool, to obtain composite filler modified silicone paste A3.

[0038] Example 4 Add 2.4 kg of KM-50, 3.4 kg of KM-500, and 2.65 kg of KM-60000 dimethyl silicone oil (Hubei Xingfa Chemical Group Co., Ltd.) to the disperser. Start stirring and add 0.2 kg of hexadecylmethyldimethoxysilane (Hubei Jianghan New Material Co., Ltd.). Continue stirring and add 0.2 kg of silica aerogel (Hubei Xingrui Silicon Materials Co., Ltd., silica aerogel 20) and 0.8 kg of precipitated silica HL-915 (Fujian Sanming Heli New Material Technology Co., Ltd.). The mixture was stirred until homogeneous, and 0.05 kg of D80 dibutyltin dilaurate catalyst (Hubei Xinlantian New Materials Co., Ltd.) was added. 100% humid air generated by distilled water was intermittently introduced, and 0.3 kg of α,ω-dihydroxypolydimethylsiloxane (WS-62M, Wacker Chemie (China) Co., Ltd.) was added. The mixture was stirred at room temperature for 2 hours, then heated to 85-90℃, and vacuum was turned on to maintain 500±50 Pa. Stirring was continued for 5 hours, then heating was stopped and the mixture was cooled to obtain composite filler modified silicone paste A4.

[0039] Comparative Example 1 In Example 1, 8.45 kg KM-50 dimethyl silicone oil was replaced with 8.45 kg KM-10, and the rest was the same as in Example 1, resulting in a combined filler-modified silicone paste A1-1.

[0040] The silicone paste prepared above was emulsified with 10% silicone paste, 1.5% AEO-3, 1% AEO-9, 0.3% xanthan gum, and 87.2% distilled water to obtain a water-based defoamer. The defoaming and foam-suppressing performance of the water-based defoamer was tested according to GB / T 26527-2024.

[0041] The defoaming and foam-inhibiting properties of Examples 1 to 4 and Comparative Example 1 are shown in Table 1.

[0042] Table 1. Defoaming and foam-inhibiting performance of Examples 1 to 4 and Comparative Example 1

[0043] Example 5 Add 8.55 kg of KM-500 dimethyl silicone oil (Hubei Xingfa Chemical Group Co., Ltd.) to a disperser, start stirring and add 0.2 kg of hexadecylmethyldimethoxysilane (Hubei Jianghan New Material Co., Ltd.), continue stirring and add 0.1 kg of silica aerogel (Hubei Xingrui Silicon Material Co., Ltd., silica aerogel 20) and 0.8 kg of precipitated silica HL-915 (Fujian Sanming Heli New Material Technology Co., Ltd.), stir and mix evenly, add 0.05 kg of D80 dibutyltin dilaurate catalyst (Hubei Xinlantian New Material Co., Ltd.), intermittently pass 100% humid air generated by distilled water, add 0.3 kg of α,ω-dihydroxypolydimethylsiloxane (WS-62M, Wacker Chemie (China) Co., Ltd.), stir and mix at room temperature for 2 h, raise the temperature to 85-90℃, turn on the vacuum and maintain 500±50 Pa, continue stirring for 5 h, stop heating and cool, to obtain composite filler adhesive modified silicone paste A5.

[0044] Example 6 Add 8.25 kg of KM-500 dimethyl silicone oil (Hubei Xingfa Chemical Group Co., Ltd.) to a disperser, start stirring and add 0.4 kg of dodecylmethyldimethoxysilane (Hubei Jianghan New Material Co., Ltd.), continue stirring and add 0.2 kg of silica aerogel (Hubei Xingrui Silicon Material Co., Ltd., silica aerogel 20) and 0.8 kg of precipitated silica HL-915 (Fujian Sanming Heli New Material Technology Co., Ltd.), stir and mix evenly, add 0.05 kg of D80 dibutyltin dilaurate catalyst (Hubei Xinlantian New Material Co., Ltd.), intermittently pass 100% humid air generated by distilled water, add 0.3 kg of α,ω-dihydroxypolydimethylsiloxane (WS-62M, Wacker Chemie (China) Co., Ltd.), stir and mix at room temperature for 2 h, raise the temperature to 85-90℃, turn on the vacuum and maintain 500±50 Pa, continue stirring for 5 h, stop heating and cool, to obtain composite filler adhesive modified silicone paste A6.

[0045] Example 7 Add 8.15 kg of KM-500 dimethyl silicone oil (Hubei Xingfa Chemical Group Co., Ltd.) to a disperser, start stirring and add 0.5 kg of octadecylmethyldimethoxysilane (Hubei Jianghan New Material Co., Ltd.), continue stirring and add 0.2 kg of silica aerogel (Hubei Xingrui Silicon Materials Co., Ltd., silica aerogel 20) and 0.8 kg of precipitated silica HL-915 (Fujian Sanming Heli New Material Technology Co., Ltd.), stir and mix evenly, add 0.05 kg of D80 dibutyltin dilaurate catalyst (Hubei Xinlantian New Material Co., Ltd.), intermittently pass 100% humid air generated by distilled water, add 0.3 kg of α,ω-dihydroxypolydimethylsiloxane (WS-62M, Wacker Chemie (China) Co., Ltd.), stir and mix at room temperature for 2 h, raise the temperature to 85-90℃, turn on the vacuum and maintain 500±50 Pa, continue stirring for 5 h, stop heating and cool, to obtain composite filler adhesive modified silicone paste A7.

[0046] Comparative Example 2 Add 8.65 kg of KM-500 dimethyl silicone oil (Hubei Xingfa Chemical Group Co., Ltd.) to a disperser, start stirring and add 0.2 kg of silica aerogel (Hubei Xingrui Silicon Materials Co., Ltd., silica aerogel 20) and 0.8 kg of precipitated silica HL-915 (Fujian Sanming Heli New Materials Technology Co., Ltd.), stir and mix evenly, add 0.05 kg of D80 dibutyltin dilaurate catalyst (Hubei Xinlantian New Materials Co., Ltd.), intermittently pass 100% humid air generated by distilled water, add 0.3 kg of α,ω-dihydroxypolydimethylsiloxane (WS-62M, Wacker Chemie (China) Co., Ltd.), stir and mix at room temperature for 2 h, raise the temperature to 85-90℃, turn on the vacuum and maintain 500±50 Pa, continue stirring for 5 h, stop heating and cool, to obtain composite filler adhesive modified silicone paste A5-1.

[0047] The silicone paste prepared above was emulsified with 10% silicone paste, 2% AEO-3, 0.5% AEO-9, 0.3% xanthan gum, and 87.2% distilled water to obtain a water-based defoamer. The defoaming and foam-suppressing performance of the water-based defoamer was tested according to GB / T 26527-2024.

[0048] The defoaming and foam-inhibiting properties of Examples 5 to 7 and Comparative Example 2 are shown in Table 2.

[0049] Table 2 shows the defoaming and foam-inhibiting performance of Examples 5 to 7 and Comparative Example 2.

[0050] Example 8 Add 8.35 kg of KM-500 dimethyl silicone oil (Hubei Xingfa Chemical Group Co., Ltd.) to a disperser, start stirring and add 0.3 kg of hexadecylmethyldimethoxysilane (Hubei Jianghan New Material Co., Ltd.), continue stirring and add 0.1 kg of silica aerogel (Hubei Xingrui Silicon Material Co., Ltd., silica aerogel 20) and 0.9 kg of precipitated silica HL-915 (Fujian Sanming Heli New Material Technology Co., Ltd.), stir and mix evenly, add 0.05 kg of D80 dibutyltin dilaurate catalyst (Hubei Xinlantian New Material Co., Ltd.), intermittently pass 100% humid air generated by distilled water, add 0.3 kg of α,ω-dihydroxypolydimethylsiloxane (WS-62M, Wacker Chemie (China) Co., Ltd.), stir and mix at room temperature for 2 h, raise the temperature to 85-90℃, turn on the vacuum and maintain 500±50 Pa, continue stirring for 5 h, stop heating and cool, to obtain composite filler adhesive modified silicone paste A8.

[0051] Example 9 Add 8.35 kg of KM-500 dimethyl silicone oil (Hubei Xingfa Chemical Group Co., Ltd.) to a disperser, start stirring and add 0.3 kg of hexadecylmethyldimethoxysilane (Hubei Jianghan New Material Co., Ltd.), continue stirring and add 0.5 kg of silica aerogel (Hubei Xingrui Silicon Material Co., Ltd., silica aerogel 20) and 0.5 kg of precipitated silica HL-915 (Fujian Sanming Heli New Material Technology Co., Ltd.), stir and mix evenly, add 0.05 kg of D80 dibutyltin dilaurate catalyst (Hubei Xinlantian New Material Co., Ltd.), intermittently pass 100% humid air generated by distilled water, add 0.3 kg of α,ω-dihydroxypolydimethylsiloxane (WS-62M, Wacker Chemie (China) Co., Ltd.), stir and mix at room temperature for 2 h, raise the temperature to 85-90℃, turn on the vacuum and maintain 500±50 Pa, continue stirring for 5 h, stop heating and cool, to obtain composite filler adhesive modified silicone paste A9.

[0052] Example 10 Add 8.35 kg of KM-500 dimethyl silicone oil (Hubei Xingfa Chemical Group Co., Ltd.) to a disperser, start stirring and add 0.3 kg of hexadecylmethyldimethoxysilane (Hubei Jianghan New Material Co., Ltd.), continue stirring and add 0.9 kg of silica aerogel (Hubei Xingrui Silicon Material Co., Ltd., silica aerogel 20) and 0.1 kg of precipitated silica HL-915 (Fujian Sanming Heli New Material Technology Co., Ltd.), stir and mix evenly, add 0.05 kg of D80 dibutyltin dilaurate catalyst (Hubei Xinlantian New Material Co., Ltd.), intermittently pass 100% humid air generated by distilled water, add 0.3 kg of α,ω-dihydroxypolydimethylsiloxane (WS-62M, Wacker Chemie (China) Co., Ltd.), stir and mix at room temperature for 2 h, raise the temperature to 85-90℃, turn on the vacuum and maintain 500±50 Pa, continue stirring for 5 h, stop heating and cool, to obtain composite filler adhesive modified silicone paste A10.

[0053] Comparative Example 3 In Example 8, 0.1 kg of silica aerogel (Hubei Xingrui Silicon Materials Co., Ltd., silica aerogel 20) and 0.9 kg of precipitated silica HL-915 (Fujian Sanming Heli New Materials Technology Co., Ltd.) were changed to a total of 1 kg of precipitated silica HL-915 (i.e., 0.1 kg of silica aerogel was replaced with 0.1 kg of precipitated silica HL-915), and the rest was the same as in Example 8, resulting in a combined filler adhesive modified silicone paste A8-1.

[0054] Comparative Example 4 In Example 8, 0.1 kg of silica aerogel (Hubei Xingrui Silicon Materials Co., Ltd., silica aerogel 20) and 0.9 kg of precipitated silica HL-915 (Fujian Sanming Heli New Materials Technology Co., Ltd.) were changed to a total of 1 kg of silica aerogel 20 (i.e., 0.9 kg of precipitated silica HL-915 was replaced with 0.9 kg of silica aerogel 20), and the rest was the same as in Example 8, resulting in a combined filler adhesive modified silicone paste A8-2.

[0055] The silicone paste prepared above was emulsified with 10% silicone paste, 1.5% AEO-3, 1% AEO-9, 0.3% xanthan gum, and 87.2% distilled water to obtain a water-based defoamer. The defoaming and foam-suppressing performance of the water-based defoamer was tested according to GB / T 26527-2024.

[0056] The defoaming and foam-suppressing properties of Examples 8 to 10 and Comparative Examples 3 and 4 are shown in Table 3.

[0057] Table 3. Defoaming and foam-inhibiting performance of Examples 8 to 10 and Comparative Examples 3 and 4

[0058] Example 11 Add 8.5 kg of KM-500 dimethyl silicone oil (Hubei Xingfa Chemical Group Co., Ltd.) to a disperser, start stirring and add 0.3 kg of hexadecylmethyldimethoxysilane (Hubei Jianghan New Material Co., Ltd.), continue stirring and add 0.2 kg of silica aerogel (Hubei Xingrui Silicon Material Co., Ltd., silica aerogel 20) and 0.8 kg of precipitated silica HL-915 (Fujian Sanming Heli New Material Technology Co., Ltd.), stir and mix evenly, add 0.1 kg of D80 dibutyltin dilaurate catalyst (Hubei Xinlantian New Material Co., Ltd.), intermittently pass 100% humid air generated by distilled water, add 0.3 kg of α,ω-dihydroxypolydimethylsiloxane (WS-62M, Wacker Chemie (China) Co., Ltd.), stir and mix at room temperature for 2 h, raise the temperature to 85-90℃, turn on the vacuum and maintain 500±50 Pa, continue stirring for 5 h, stop heating and cool, to obtain composite filler adhesive modified silicone paste A11.

[0059] Comparative Example 5 Add 8.5 kg of KM-500 dimethyl silicone oil (Hubei Xingfa Chemical Group Co., Ltd.) to a disperser, start stirring and add 0.3 kg of hexadecylmethyldimethoxysilane (Hubei Jianghan New Material Co., Ltd.), continue stirring and add 0.2 kg of silica aerogel (Hubei Xingrui Silicon Material Co., Ltd., silica aerogel 20) and 0.8 kg of precipitated silica HL-915 (Fujian Sanming Heli New Material Technology Co., Ltd.), stir and mix evenly, intermittently pass in humid air with 100% humidity generated by distilled water, add 0.3 kg of α,ω-dihydroxypolydimethylsiloxane (WS-62M, Wacker Chemie (China) Co., Ltd.), stir and mix at room temperature for 2 hours, raise the temperature to 85-90℃, turn on the vacuum and maintain 500±50 Pa, continue stirring for 5 hours, stop heating and cool, to obtain composite filler adhesive modified silicone paste A11-1.

[0060] Example 12 Add 8.3 kg of KM-500 dimethyl silicone oil (Hubei Xingfa Chemical Group Co., Ltd.) to a disperser, start stirring and add 0.3 kg of hexadecylmethyldimethoxysilane (Hubei Jianghan New Material Co., Ltd.), continue stirring and add 0.2 kg of silica aerogel (Hubei Xingrui Silicon Materials Co., Ltd., silica aerogel 20) and 0.8 kg of precipitated silica HL-915 (Fujian Sanming Heli New Material Technology Co., Ltd.), stir and mix evenly, add 0.2 kg of D60 organotitanium complex catalyst (Hubei Xinlantian New Material Co., Ltd.), intermittently pass 100% humid air generated by distilled water, add 0.3 kg of α,ω-dihydroxypolydimethylsiloxane (WS-62M, Wacker Chemie (China) Co., Ltd.), stir and mix at room temperature for 2 h, raise the temperature to 85-90℃, turn on the vacuum and maintain 500±50 Pa, continue stirring for 5 h, stop heating and cool, to obtain composite filler adhesive modified silicone paste A12.

[0061] Example 13 Add 8.2 kg of KM-500 dimethyl silicone oil (Hubei Xingfa Chemical Group Co., Ltd.) to a disperser, start stirring and add 0.3 kg of hexadecylmethyldimethoxysilane (Hubei Jianghan New Material Co., Ltd.), continue stirring and add 0.2 kg of silica aerogel (Hubei Xingrui Silicon Materials Co., Ltd., silica aerogel 20) and 0.8 kg of precipitated silica HL-915 (Fujian Sanming Heli New Material Technology Co., Ltd.), stir and mix evenly, add 0.3 kg of D60 organotitanium complex catalyst (Hubei Xinlantian New Material Co., Ltd.), intermittently pass 100% humid air generated by distilled water, add 0.3 kg of α,ω-dihydroxypolydimethylsiloxane (WS-62M, Wacker Chemie (China) Co., Ltd.), stir and mix at room temperature for 2 h, raise the temperature to 85-90℃, turn on the vacuum and maintain 500±50 Pa, continue stirring for 5 h, stop heating and cool, to obtain composite filler adhesive modified silicone paste A12.

[0062] Comparative Example 6 Add 8.5 kg of KM-500 dimethyl silicone oil (Hubei Xingfa Chemical Group Co., Ltd.) to a disperser, start stirring and add 0.3 kg of hexadecylmethyldimethoxysilane (Hubei Jianghan New Material Co., Ltd.), continue stirring and add 0.2 kg of silica aerogel (Hubei Xingrui Silicon Material Co., Ltd., silica aerogel 20), 0.8 kg of precipitated silica HL-915 (Fujian Sanming Heli New Material Technology Co., Ltd.), stir and mix evenly, add 0.2 kg of D60 organotitanium complex catalyst (Hubei Xinlantian New Material Co., Ltd.), intermittently pass in 100% humid air generated by distilled water, stir and mix at room temperature for 2 hours, raise the temperature to 150-155℃, turn on the vacuum and maintain 500±50 Pa, continue stirring for 5 hours, stop heating and cool, to obtain composite filler adhesive modified silicone paste A12-1.

[0063] The silicone paste prepared above was emulsified with 10% silicone paste, 1.5% AEO-3, 1% AEO-9, 0.3% xanthan gum, and 87.2% distilled water to obtain a water-based defoamer. The defoaming and foam-suppressing performance of the water-based defoamer was tested according to GB / T 26527-2024.

[0064] The experimental results of Examples 11 to 13 and Comparative Examples 5 and 6 are shown in Table 4. Table 4. Experimental results of Examples 11 to 13 and Comparative Examples 5 and 6

[0065] The specific embodiments described in this application are merely illustrative of the application and are not intended to limit the application. Those skilled in the art can make modifications to these embodiments without contributing any inventive step after reading this specification.

Claims

1. A method for preparing a composite filler silicone paste, characterized in that, include: In dimethyl silicone oil, long-chain alkyl siloxanes are added, and silica aerogel, precipitated silica and catalyst are added while stirring. Moist air is intermittently introduced and stirred to carry out the first mixing reaction. Add hydroxyl silicone oil and stir to carry out the second mixing reaction; After heating, the mixture was stirred under vacuum to carry out the third mixing reaction. Heating was then stopped and the mixture was cooled to obtain a composite filler-modified silicone paste.

2. The method for preparing a combined filler silicone paste according to claim 1, characterized in that, The dimethyl silicone oil comprises a mixture of one or more dimethyl silicone oils with viscosities ranging from 50 cSt to 200,000 mPa·s, accounting for 65-95% of the viscous silicone paste.

3. The method for preparing a combined filler silicone paste according to claim 1, characterized in that, The long-chain alkylsiloxane comprises one or more combinations of octylmethyldimethoxysilane, octylmethyldiethoxysilane, dodecylmethyldimethoxysilane, dodecylmethyldiethoxysilane, hexadecylmethyldimethoxysilane, hexadecylmethyldiethoxysilane, octadecylmethyldimethoxysilane, and octadecylmethyldiethoxysilane, accounting for 0.5-10% of the viscous silicone paste, preferably 1-5%.

4. The method for preparing a combined filler silicone paste according to claim 1, characterized in that, The silica aerogel has a BET surface area of ​​500-1200m. 2 / g; The precipitated silica has a BET specific surface area of ​​80-400m. 2 / g; The ratio of silica aerogel to precipitated silica is 1:5 to 5:1, and the sum of the two constitutes 3-25% of the viscous silicone paste.

5. The method for preparing a combined filler silicone paste according to claim 1, characterized in that, The catalyst comprises one or more combinations of organotin compounds, organotitanium compounds, modified organotin compounds, and modified organotitanium compounds, accounting for 0.05-5% of the viscous silicone paste, preferably 0.2-3%.

6. The method for preparing a combined filler silicone paste according to claim 1, characterized in that, The hydroxyl silicone oil is a single-ended hydroxyl silicone oil, a double-ended hydroxyl silicone oil, or a combination thereof, with a viscosity of 10 cSt to 1000 cSt and a hydroxyl content of 0.1% to 10.0%; the hydroxyl silicone oil accounts for 1% to 15% of the mass percentage of the combined filler silicone paste.

7. The method for preparing a combined filler silicone paste according to claim 1, characterized in that, The intermittent introduction of humid air includes humid air in the form of water vapor generated from tap water, water vapor generated by heating distilled water, or water vapor carried out by filtered compressed gas or nitrogen through water bodies.

8. The method for preparing a combined filler silicone paste according to claim 1, characterized in that, The first mixing reaction takes 1 to 6 hours; The second mixing reaction takes 0.5 to 2 hours; The third mixing reaction is carried out at a temperature of 60–250°C, a vacuum of 50–5000 Pa, and a time of 2–10 hours.

9. A composite filler-modified silicone paste prepared by the method according to any one of claims 1 to 8.

10. A defoamer, characterized in that, It comprises the combined filler silicone paste of claim 9, as well as an emulsifier, a thickener, and a diluent.

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