Organic silicon defoaming composition and preparation method therefor

Abstract

The present invention relates to an organic silicon defoaming composition and a preparation method therefor. A high-hydrogen-content polyorganosiloxane and a high-vinyl-content vinyl polysiloxane are reacted under the action of a catalyst, so as to form a solid organic silicon powder; a polyorganosiloxane containing hydrogen at a terminal group and an α-olefin react under the action of a catalyst to form a polyorganosiloxane containing hydrogen at a terminal alkyl; a polyorganosiloxane containing hydrogen at a pendant group and an α-olefin react under the action of a catalyst to form a polyorganosiloxane containing hydrogen at a pendant alkyl; and the solid organic silicon powder, the polyorganosiloxane containing hydrogen at a pendant alkyl and the polyorganosiloxane containing hydrogen at a terminal alkyl are mixed and charged into a reactor, such that the solid organic silicon powder is subjected to a cross-linking reaction with residual hydrogen in the polyorganosiloxane containing hydrogen at a terminal alkyl and the polyorganosiloxane containing hydrogen at a pendant alkyl, so as to form a polymer having an SiOSi spatial structure, and then an organic silicon resin is added thereto to prepare an organic silicon defoaming composition, thereby improving the cross-linking density of the organic silicon defoaming composition and greatly improving the defoaming and anti-forming performance of the defoaming agent.

Description

A kind of organosilicon defoaming composition and preparation method thereof Technical Field

[0001] The present invention relates to an organosilicon defoaming composition and a preparation method thereof. The organosilicon defoaming composition belongs to fine chemicals, and therefore the present invention belongs to the technical field of fine chemical preparations. Background Art

[0002] During industrial production, the generation of large amounts of foam can severely impact production, reducing the efficiency of production equipment, delaying production personnel's working time, and affecting product quality. Methods for eliminating harmful foam can be categorized as physical or chemical, with defoaming agents being one of the chemical methods. In recent years, defoamers have been widely promoted and applied. Currently, defoamers on the market are classified by active ingredient, primarily into polyethers, silicones, mineral oils, fatty alcohols, and other polymers. Silicone defoamers are particularly popular among consumers due to their stable chemical properties, minimal side effects, and strong foam removal and suppression capabilities.

[0003] The organosilicon defoaming composition is the core component of organosilicon defoamers. Its defoaming speed and antifoaming performance directly affect the performance of the final product. For organosilicon defoamers, improving the defoaming and antifoaming performance of its active ingredients is the main optimization direction of organosilicon defoamers. The original organosilicon defoaming composition was prepared by polydimethylsiloxane and silicon dioxide through a specific processing technology. For example, the defoaming agent composition introduced in GB1051687A was prepared by heating polydimethylsiloxane and hydrophilic silicon dioxide, but its antifoaming performance was poor. Later, DE-OS2925722 replaced hydrophilic silicon dioxide with hydrophobic silicon dioxide; US-A4145308 introduced (CH3)3SiO 1 / 2and SiO2 units; US4395352 describes an antifoaming agent composition containing a high-viscosity polydimethylsiloxane fluid and finely dispersed hydrophobic particles, which can be used as a defoaming agent by itself or in the form of an emulsion; US3691091 discloses an organosilicon emulsion of an aqueous liquid defoaming agent, wherein the organosilicon is composed of a polydimethylsiloxane fluid, silicon dioxide, and an organosilicon compound or oligomer containing alkoxy and / or silanol groups; EP0163541 discloses a method for preparing an organosilicon defoaming agent by reacting a mixture of components including a preformed polyorganosiloxane polymer with one or more hydroxyl and / or hydrocarbonoxy groups, an organosilicon resin, a filler, and a catalyst to promote the reaction; EP-A-578424 prepares a foam control agent using a polydiorganosiloxane having some side chains with long-chain alkyl groups, each alkyl side chain containing 9 to 35 carbon atoms. The above patents all mention non-cross-linked silicone polymers, and all introduce hydrophobic particles to improve the foam breaking performance of the composition. These compositions are not sufficiently cross-linked, and the subsequent foam suppression performance is poor. At the same time, although the hydrophobic particles can improve the foam performance in the short term, with continuous use, the hydrophobic particles in the later composition may precipitate or agglomerate, the compatibility of the composition will deteriorate, and the performance will be easily attenuated.

[0004] Next, EP163541B1, CN102698475A, and CN104274998A describe the reaction of a polysiloxane containing terminal hydroxyl groups with a polyorganosiloxane containing other reactive functional groups under the action of a catalyst to form a branched polyorganosiloxane. This branched polyorganosiloxane is then used in place of standard polysiloxane and mixed with hydrophilic silica. The resulting organosilicon defoaming composition has a higher degree of crosslinking, but the viscosity is too high, making it difficult to emulsify and disperse in water. US5153258 describes the introduction of lightly crosslinked polyorganosiloxanes into the system to improve the composition's foam removal and suppression properties. For example, vinyl polyorganosiloxane, hydrogen-containing polyorganosiloxane, or hydroxyl-containing polyorganosiloxane, and alkyl silicate undergo crosslinking reactions under the action of a catalyst, but the degree of crosslinking is difficult to control. US5486306 describes a defoamer synthesized directly by reacting a hydrogen-containing polyorganosiloxane with an α-olefin. This process is simple to synthesize, but the resulting defoamer has poor defoaming properties and is only used in laundry detergents. It is prone to silicon spots on fabrics when in contact with them. WO2007137948A1 describes the addition of trimethylsiloxy-terminated polydimethylsiloxane to dilute the reaction of hydrogenated polyorganosiloxane and vinylated polyorganosiloxane. However, the diluent's contribution to defoaming performance is minimal, and the reaction of hydrogenated polyorganosiloxane and vinylated polyorganosiloxane results in high viscosity, making it difficult to control. The resulting defoamer composition exhibits poor foam suppression performance. CN105107237A synthesizes terminal alkyl polysiloxane and pendant alkyl polysiloxane using terminal hydrogenated polysiloxane and pendant hydrogenated polysiloxane, respectively, and finally introduces a silanol polymer as a crosslinking agent to increase the crosslinking degree of the composition. While all of these patents improve defoaming performance by increasing the crosslinking degree of the composition, the aggregation and precipitation of hydrophobic particles still present problems. Summary of the Invention

[0005] The present invention relates to an organosilicon defoaming composition and a preparation method thereof. The invention comprises the following steps: reacting a high hydrogen-containing polyorganosiloxane and a high vinyl content vinyl polysiloxane under the action of a catalyst to form a solid organosilicon powder; reacting a terminal hydrogen-containing polyorganosiloxane with an α-olefin under the action of a catalyst to form a terminal alkyl hydrogen-containing polyorganosiloxane; reacting a side hydrogen-containing polyorganosiloxane with an α-olefin under the action of a catalyst to form a side alkyl hydrogen-containing polyorganosiloxane; mixing the solid organosilicon powder, the side alkyl hydrogen-containing polyorganosiloxane and the terminal alkyl polyorganosiloxane into a reactor, so that the solid organosilicon powder reacts with the remaining hydrogen in the terminal and side alkyl hydrogen-containing polyorganosiloxanes to form a SiOSi defoaming composition. The invention relates to a novel organosilicon defoaming composition comprising a first polysiloxane and a second polysiloxane. The first polysiloxane comprises a first polysiloxane and a second polysiloxane. The first polysiloxane comprises a first polysiloxane and a second polysiloxane. The first polysiloxane comprises a first polysiloxane and a second polysiloxane. The first polysiloxane comprises a first polysiloxane and a second polysiloxane. The first polysiloxane comprises a first polysiloxane and a second polysiloxane. The first polysiloxane comprises a first polysiloxane and a second polysiloxane. The first polysiloxane comprises a first polysiloxane and a second polysiloxane. The first polysiloxane comprises a first polysiloxane and a second polysiloxane. The first polysiloxane comprises a first polysiloxane and a second polysiloxane. The first polysiloxane comprises a first polysiloxane and a second polysiloxane. The first polysiloxane and the second polysiloxane have ...

[0006] The organosilicon defoaming composition of the present invention is composed of the following substances:

[0007] A. Hydrogen-terminated polyorganosiloxane

[0008] At least one of the following general structural formulas:

[0009] R 0 2HSiO(Me2SiO) a SiHR 0 2

[0010] In the formula, the substituent R 0 The same or different, is a hydrocarbon group with 1 to 12 carbon atoms, selected from alkyl, cycloalkyl, aryl, wherein the alkyl group is selected from methyl, ethyl, n-propyl, n-butyl, isobutyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, isooctyl, n-nonyl, n-decyl, n-dodecyl; the cycloalkyl group is selected from cyclopentyl, cyclohexylethyl; the aryl group is selected from phenyl, benzyl, phenylethyl, 2-phenylpropyl; preferably R 0 is a methyl group; the subscript a is an integer from 10 to 200; and its usage is 20-40% of the total mass of the defoaming composition.

[0011] B. Side-containing hydrogen polysiloxane

[0012] At least one of the following general structural formulas:

[0013] Me3SiO(R1 HSiO) b (R 1 2SiO) c SiMe3

[0014] In the formula, the substituent R 1 The same or different hydrocarbon groups with 1 to 18 carbon atoms are selected from alkyl, cycloalkyl, and aryl groups, wherein the alkyl group is selected from methyl, ethyl, n-propyl, n-butyl, isobutyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, isooctyl, n-nonyl, n-decyl, n-dodecyl, and n-octadecyl; the cycloalkyl group is selected from cyclopentyl and cyclohexylethyl; the aryl group is selected from phenyl, benzyl, phenylethyl, and 2-phenylpropyl; preferably R 1 is a methyl group; subscript b is an integer of 10 to 100; subscript c is an integer of 10 to 400; and its usage is 20-40% of the total mass of the defoaming composition.

[0015] C.α-olefins

[0016] The α-olefin is a mixture of any one or more of linear α-olefins, α-aromatic olefins or branched α-olefins, including α-octene, α-decene, α-dodecene, α-tetradecene, α-hexadecene, α-octadecene, α-eicosene, a C20-C24 linear α-olefin mixture, a C24-C28 linear α-olefin mixture, α-triacontene, α-methylstyrene, and α-styrene. The α-olefin can be used alone or mixed in any proportion. The α-olefin is added in two parts, with the first part accounting for 1-5% of the total mass of the defoaming composition and the second part accounting for 10-30% of the total mass of the defoaming composition.

[0017] D. Solid silicone powder

[0018] Solid organosilicon powder is formed by reacting high hydrogen polysiloxane D1 and high vinyl content vinyl polysiloxane D2 under the action of platinum catalyst D3, and finally ground to obtain solid organosilicon powder, the amount of which is 10-20% of the total mass of the defoaming composition;

[0019] The general structural formula of high hydrogen-containing polysiloxane D1 is as follows:

[0020] H c R 3 3-c SiO(SiR 3 HO) d (SiR 3 2O) b SiR 3 3-c H c

[0021] R 3are alkyl groups having 1 to 5 carbon atoms, which may be the same or different; subscript c is 0, 1, or 2; subscript d is an integer from 100 to 300; subscript b is an integer from 50 to 1600; the hydrogen content of the high hydrogen polysiloxane is ≥ 0.1%; and the amount used is 10-30% of the total mass of the solid organosilicon powder;

[0022] The general structural formula of high vinyl content vinyl polysiloxane D2 is as follows:

[0023] Vi e R 4 3-e SiO(SiR 4 ViO) f (SiR 4 2O) g SiR 4 3-e Vi e

[0024] R 4 The value range is similar to R 3 Same; Vi is vinyl, subscript e is 0 or 1, subscript f is 30-80; subscript g is 20-80; the molecular weight of the high vinyl content vinyl polysiloxane D2 is less than 10000; the amount accounts for 70-90% of the total mass of the solid silicone powder

[0025] The platinum catalyst D3 is selected from a platinum-alcohol complex, a platinum-olefin complex, a platinum-alkoxide complex, a platinum-ether complex, a platinum-ketone complex, a chloroplatinic acid isopropanol solution, and a platinum-vinyl complex; the amount used is 0.01%-0.05% of the total mass of the high hydrogen-containing polysiloxane and the high vinyl content vinyl polysiloxane.

[0026] E. Catalyst

[0027] The catalyst is selected from a platinum-alcohol complex, a platinum-olefin complex, a platinum-alkoxide complex, a platinum-ether complex, a platinum-ketone complex, a chloroplatinic acid isopropanol solution, and a platinum-vinyl complex, preferably a chloroplatinic acid isopropanol solution; the amount of the catalyst is 3 to 20 ppm (calculated as platinum) of the total mass of the terminal hydrogen-containing polysiloxane A, the side hydrogen-containing polysiloxane B, the α-olefin C and the solid organosilicon powder D, and is used in three parts.

[0028] F.MQ silicone resin

[0029] The MQ silicone resin is an MQ resin composed of chain segments (CH3)3SiOl / 2 (M units) and chain segments SiO4 / 2 (Q units), the molar ratio between the two being (0.4-1.2):1.0, and the amount used is 2-8% of the total mass of the defoaming composition.

[0030] The preparation method of the organosilicon defoaming composition of the present invention is as follows:

[0031] (1) adding a terminal hydrogen-containing polyorganosiloxane A and a first portion of an α-olefin into a reaction vessel, adding a catalyst when the temperature is raised to 50-80° C., and maintaining the temperature for 0.5-1.5 hours to obtain an alkyl-terminated hydrogen-containing polyorganosiloxane X;

[0032] (2) adding the side hydrogen-containing polyorganosiloxane B and the second part of the α-olefin into another reaction vessel, adding the catalyst when the temperature is raised to 50-80° C., raising the temperature to 120-200° C., and keeping the temperature for 0.5-1.5 hours to obtain the side alkyl hydrogen-containing polyorganosiloxane Y;

[0033] (3) adding a catalyst to solid organosilicon powder D, side alkyl hydrogen-containing polyorganosiloxane Y, and terminal alkyl hydrogen-containing polyorganosiloxane X at a temperature of 50 to 80° C., raising the temperature to 110 to 180° C., and maintaining the temperature for 0.5 to 1.5 hours;

[0034] (4) Add MQ silicone resin to the mixture in (3), keep the mixture at 100-160° C. for 1-5 hours, and cool it to room temperature to obtain an organosilicon defoaming composition.

[0035] For certain applications, the organosilicon defoaming composition of the present invention can be prepared into an emulsion defoaming agent or a solid defoaming agent for use.

[0036] If the silicone defoaming composition of the present invention is prepared as an emulsion defoamer, techniques for preparing silicone emulsions familiar to those skilled in the art can be used. Generally, a silicone emulsion contains the silicone defoaming composition as an oil phase, one or more surfactants, water, and standard additives (such as preservatives, viscosity modifiers, anti-gelling agents, and / or thickeners). The surfactant can be selected from anionic, cationic, nonionic, or amphoteric materials, or a mixture of one or more of these.

[0037] The organosilicon defoaming composition of the present invention is prepared into a solid powder or granular defoamer. The preparation of the solid powder or granular defoamer can be carried out using methods well known to those skilled in the art, such as spray drying or agglomeration granulation, and using additives well known to those skilled in the art. DETAILED DESCRIPTION

[0038] Solid organosilicon powder examples and comparative examples

[0039] Example 1

[0040] 100g high hydrogen polysiloxane 100gH2MeSiO(SiMeHO) 130 (SiMe2O) 1600SiMeH2, 900g high vinyl content vinyl polysiloxane Me3SiO (SiMeViO) 30 (SiMe2O) 80 SiMe3 was mixed, 0.1 g of chloroplatinic acid isopropanol solution was added at 40 °C, then the temperature was raised to 50 °C for reaction for 6 h, and the temperature was lowered to room temperature to obtain organosilicon powder solid D1;

[0041] Example 2

[0042] 200g high hydrogen polysiloxane H3SiO[Si(C2H5)HO)] 150 [(SiMe(C2H5)O)] 1000 SiH3, 800g high vinyl content vinyl polysiloxane ViMe2SiO (SiMeViO) 80 (SiMe2O) 20 SiViMe2 was mixed, 0.2 g of platinum-alcohol complex was added at 50 °C, then the temperature was raised to 80 °C for reaction for 5 h, and the temperature was lowered to room temperature to obtain organosilicon powder solid D2;

[0043] Example 3

[0044] 300g of high hydrogen-containing polysiloxane H(Me)(C3H7)SiO[Si(C3H7)HO)] 200 [(SiMe(C3H7)O)] 800 Si(Me)2H, 700g high vinyl content vinyl polysiloxane (C2H5)2(C3H7)SiO[Si(C2H5)ViO] 40 [Si(C2H5)2(C3H7)O] 40 Si(C2H5)2(C3H7) was mixed, 0.3 g of platinum-olefin complex was added at 60 °C, then the temperature was raised to 110 °C for reaction for 4 h, and the temperature was lowered to room temperature to obtain organosilicon powder solid D3;

[0045] Example 4

[0046] 150g of high hydrogen-containing polysiloxane (C4H9)2(C3H7)SiO[Si(C3H7)HO)] 300 [(SiMe(C3H7)O)] 500 Si(C4H9)(C3H7)2, 850g high vinyl content vinyl polysiloxane Vi(C4H9)2SiO[Si(C4H9)ViO] 20 [Si(C2H5)2(C4H9)O] 15Si(C4H9)2Vi were mixed, 0.4 g of platinum-alkoxide complex was added at 70 °C, then the temperature was raised to 150 °C for reaction for 3 h, and the temperature was lowered to room temperature to obtain organosilicon powder solid D4;

[0047] Example 5

[0048] 250g high hydrogen polysiloxane 450gH2(C5H 11 )SiO[Si(CH3)HO)] 250 [(SiMe2O)] 200 Si(C5H 11 )H2, 750g high vinyl content vinyl polysiloxane (C5H 11 )3SiO[Si(Me)ViO] 15 [Si(C5H 11 )(Me)O] 10 Si(C5H 11 ) 3 mixed, added 0.5 g of platinum-ether complex at 80 ° C, then heated to 180 ° C for 2 h, and cooled to room temperature to obtain organosilicon powder solid D5;

[0049] Example 6

[0050] 180g high hydrogen polysiloxane H3SiO[Si(CH3)HO)] 300 [(SiMe2O)] 50 SiH3, 820g high vinyl content vinyl polysiloxane ViMe2SiO[Si(Me)ViO] 60 [Si(Me)2O] 60 SiMe2Vi was mixed, 0.25 g of platinum-ketone complex was added at 90 °C, then the temperature was raised to 200 °C for reaction for 1 h, and the temperature was lowered to room temperature to obtain organosilicon powder solid D6;

[0051] Comparative Example 1 - Hydrogen content reduced

[0052] 100g hydrogen-containing polysiloxane 100gH2MeSiO(SiMeHO) 100 (SiMe2O) 1600 SiMeH2, 900g high vinyl content vinyl polysiloxane Me3SiO (SiMeViO) 30 (SiMe2O) 80 SiMe3 was mixed, 0.1 g of chloroplatinic acid isopropanol solution was added at 40 °C, then the temperature was raised to 50 °C for reaction for 6 h, and the temperature was lowered to room temperature to obtain organosilicon powder solid D7;

[0053] Comparative Example 2 - Hydrogen content reduced

[0054] 200g hydrogen-containing polysiloxane 200gH3SiO[Si(C2H5)HO)] 50 [(SiMe(C2H5)O)] 1000 SiH3, 800g high vinyl content vinyl polysiloxane ViMe2SiO (SiMeViO) 80 (SiMe2O) 20 SiViMe2 was mixed, 0.2 g of platinum-alcohol complex was added at 50 °C, then the temperature was raised to 80 °C for reaction for 5 h, and the temperature was lowered to room temperature to obtain organosilicon powder solid D8;

[0055] Comparative Example 3 - Vinyl Molecular Weight Improvement

[0056] 300g H(Me)(C3H7)SiO[Si(C3H7)HO)] 200 [(SiMe(C3H7)O)] 800 Si(Me)2H, 700g high vinyl content vinyl polysiloxane (C2H5)2(C3H7)SiO[Si(C2H5)ViO] 80 [Si(C2H5)2(C3H7)O] 40 Si(C2H5)2(C3H7) was mixed, 0.3 g of platinum-olefin complex was added at 60 °C, then the temperature was raised to 110 °C for reaction for 4 h, and the temperature was lowered to room temperature to obtain organosilicon powder solid D9;

[0057] Comparative Example 4 - Vinyl Molecular Weight Improvement

[0058] 400g of high hydrogen-containing polysiloxane (C4H9)2(C3H7)SiO[Si(C3H7)HO)] 300 [(SiMe(C3H7)O)] 500 Si(C4H9)(C3H7)2, 600g high vinyl content vinyl polysiloxane Vi(C4H9)2SiO[Si(C4H9)ViO] 70 [Si(C2H5)2(C4H9)O] 15 Si(C4H9)2Vi were mixed, 0.4 g of platinum-alkoxide complex was added at 70 °C, then the temperature was raised to 150 °C for reaction for 3 h, and the temperature was lowered to room temperature to obtain organosilicon powder solid D10;

[0059] Examples of silicone defoaming compositions

[0060] Example 7

[0061] (1) 200g of hydrogen-terminated polyorganosiloxane Me2HSiO(Me2SiO) 200SiHMe2 and 50g of α-octene were added to a reaction vessel, and when the temperature reached 50-80°C, 1ppm of chloroplatinic acid isopropanol solution was added and the temperature was kept for 0.5-1.5h to obtain terminal alkyl hydrogen-containing polyorganosiloxane X1;

[0062] (2) 400 g of side hydrogen-containing polyorganosiloxane Me2(C3H7)SiO(MeHSiO) 70 (Me2SiO) 50 SiMe2(C8H 17 ) and 100g of α-octene are added to another reaction container, and when the temperature is raised to 50-80°C, 1ppm of chloroplatinic acid isopropanol solution is added, and the temperature is raised to 120-200°C and kept warm for 0.5-1.5h to obtain a pendant alkyl hydrogen-containing polyorganosiloxane Y1;

[0063] (3) Add 1 ppm chloroplatinic acid isopropanol solution to 200 g of solid organosilicon powder D1, side alkyl hydrogenated polyorganosiloxane Y1, and terminal alkyl hydrogenated polyorganosiloxane X1 at a temperature of 50-80°C, and heat to 110-180°C for 0.5-1.5 h;

[0064] (4) Add 50 g of MQ silicone resin (M:Q=0.4:1.0) to the mixture in (3), keep it at 100-160° C. for 1-5 hours, and cool it to room temperature to obtain an organosilicon defoaming composition.

[0065] Example 8

[0066] (1) 300 g of hydrogen-terminated polyorganosiloxane Me2HSiO(Me2SiO) 32 SiHMe2 and 40 g of α-decene were added to a reaction vessel, and when the temperature reached 50-80°C, 2 ppm of a platinum-alcohol complex was added and the temperature was maintained for 0.5-1.5 h to obtain an alkyl-terminated hydrogen-containing polyorganosiloxane X2;

[0067] (2) 300 g of side hydrogen-containing polyorganosiloxane Me2(C6H5)SiO(MeHSiO) 100 (Me2SiO) 400 SiMe2(C 12 H 25 ) and 180g α-dodecene are added to another reaction container, and when the temperature is raised to 50-80°C, 2pp platinum-alcohol complex is added, and the temperature is raised to 120-200°C and kept warm for 0.5-1.5h to obtain pendant alkyl hydrogen-containing polyorganosiloxane Y2;

[0068] (3) Add 3 ppm of platinum-alcohol complex to 100 g of solid organosilicon powder D2, side alkyl hydrogen-containing polyorganosiloxane Y2, and terminal alkyl hydrogen-containing polyorganosiloxane X2 at a temperature of 50-80° C., raise the temperature to 110-180° C., and keep warm for 0.5-1.5 h;

[0069] (4) Add 80 g of MQ silicone resin (M:Q=0.6:1.0) to the mixture in (3), keep it at 100-160° C. for 1-5 hours, and cool it to room temperature to obtain an organosilicon defoaming composition.

[0070] Example 9

[0071] (1) 400 g of hydrogen-terminated polyorganosiloxane Me2HSiO(Me2SiO) 80 SiHMe2 and 30 g of α-tetradecene were added to a reaction vessel, and when the temperature reached 50-80°C, 3 ppm of a platinum-olefin complex was added and the temperature was maintained for 0.5-1.5 h to obtain an alkyl-terminated hydrogen-containing polyorganosiloxane X3;

[0072] (2) 200 g of side hydrogen-containing polyorganosiloxane Me2 (C6H 13 )SiO(MeHSiO) 17 (Me2SiO) 10 SiMe3 and 170 g of α-hexadecene were added to another reaction vessel, and when the temperature reached 50-80°C, 3 ppm of platinum-olefin complex was added. The temperature was raised to 120-200°C and kept warm for 0.5-1.5 h to obtain pendant alkyl hydrogen-containing polyorganosiloxane Y3.

[0073] (3) 180 g of solid organosilicon powder D3, side alkyl hydrogenated polyorganosiloxane Y3, and terminal alkyl hydrogenated polyorganosiloxane X3 were heated to 50-80° C., 4 ppm of platinum-olefin complex was added, and the temperature was raised to 110-180° C. and kept warm for 0.5-1.5 h;

[0074] (4) Add 20 g of MQ silicone resin (M:Q=0.8:1.0) to the mixture in (3), keep it at 100-160° C. for 1-5 hours, and cool it to room temperature to obtain an organosilicon defoaming composition.

[0075] Example 10

[0076] (1) 280 g of hydrogen-terminated polyorganosiloxane Me(C5H 11 )HSiO(Me2SiO) 10 SiHMe2 and 20 g of α-octadecene were added to a reaction vessel, and when the temperature reached 50-80°C, 5 ppm of a platinum-alkoxide complex was added and the temperature was maintained for 0.5-1.5 h to obtain an alkyl-terminated hydrogen-containing polyorganosiloxane X4;

[0077] (2) 230 g of side hydrogen-containing polyorganosiloxane Me3SiO (MeHSiO) 50 (Me2SiO) 100 SiMe2(C 18 H 37 ) and 300g α-eicosene are added to another reaction container, and when the temperature is raised to 50-80°C, 5ppm of platinum-alkoxide complex is added, and the temperature is raised to 120-200°C and kept warm for 0.5-1.5h to obtain pendant alkyl hydrogen-containing polyorganosiloxane Y4;

[0078] (3) Add 5 ppm of platinum-alkoxide complex to 100 g of solid organosilicon powder D4, side alkyl hydrogen-containing polyorganosiloxane Y4, and terminal alkyl hydrogen-containing polyorganosiloxane X4 at a temperature of 50-80° C., raise the temperature to 110-180° C., and keep the temperature for 0.5-1.5 h;

[0079] (4) Add 70 g of MQ silicone resin (M:Q=1.0:1.0) to the mixture in (3), keep the mixture at 100-160° C. for 1-5 hours, and cool it to room temperature to obtain an organosilicon defoaming composition.

[0080] Example 11

[0081] (1) 330 g of hydrogen-terminated polyorganosiloxane Me2HSiO(Me2SiO) 100 SiHMe (C6H5) and 10 g of a C20-C24 linear α-olefin mixture were added to a reaction vessel. When the temperature reached 50-80°C, 6 ppm of a platinum-ether complex was added and the temperature was maintained for 0.5-1.5 h to obtain an alkyl-terminated hydrogen-containing polyorganosiloxane X5.

[0082] (2) 350 g of side hydrogen-containing polyorganosiloxane Me3SiO(C3H7HSiO) 10 (Me2SiO) 200 SiMe3 and 130 g of α-eicosene were added to another reaction vessel, and 6 ppm of platinum-ether complex was added when the temperature reached 50-80°C. The temperature was raised to 120-200°C and kept warm for 0.5-1.5 h to obtain pendant alkyl hydrogen-containing polyorganosiloxane Y5;

[0083] (3) Add 8 ppm of platinum-ether complex to 150 g of solid organosilicon powder D5, side alkyl hydrogen-containing polyorganosiloxane Y5, and terminal alkyl hydrogen-containing polyorganosiloxane X5 at a temperature of 50-80° C., raise the temperature to 110-180° C., and keep warm for 0.5-1.5 h;

[0084] (4) Add 30 g of MQ silicone resin (M:Q=1.2:1.0) to the mixture in (3), keep it at 100-160° C. for 1-5 hours, and cool it to room temperature to obtain an organosilicon defoaming composition.

[0085] Example 12

[0086] (1) 350 g of hydrogen-terminated polyorganosiloxane Me(C8H 17 )HSiO(Me2SiO) 140 SiHMe2 and 20 g of α-styrene were added to a reaction vessel, and when the temperature reached 50-80°C, 6 ppm of a platinum-ketone complex was added and the temperature was maintained for 0.5-1.5 h to obtain an alkyl-terminated hydrogen-containing polyorganosiloxane X6.

[0087] (2) 200 g of side hydrogen-containing polyorganosiloxane Me2 (C 11 H 23 )SiO(MeHSiO) 85 (Me2SiO) 290 SiMe3 and 250 g of α-triacontene were added to another reaction vessel, and 6 ppm of platinum-ketone complex was added when the temperature reached 50-80°C. The temperature was raised to 120-200°C and kept warm for 0.5-1.5 h to obtain pendant alkyl hydrogen-containing polyorganosiloxane Y6;

[0088] (3) Add 6 ppm of platinum-ketone complex to 120 g of solid organosilicon powder D6, side alkyl hydrogen-containing polyorganosiloxane Y6, and terminal alkyl hydrogen-containing polyorganosiloxane X6 at a temperature of 50-80° C., then heat to 110-180° C. and keep warm for 0.5-1.5 h;

[0089] (4) Add 60 g of MQ silicone resin (M:Q=0.5:1.0) to the mixture in (3), keep it at 100-160° C. for 1-5 hours, and cool it to room temperature to obtain an organosilicon defoaming composition.

[0090] Example 13

[0091] (1) 310 g of hydrogen-terminated polyorganosiloxane Me2HSiO(Me2SiO) 110 SiHMe(C 10 H 21 ) and 50g of α-octadecene were added to a reaction vessel, and 5ppm of platinum-vinyl complex was added when the temperature was raised to 50-80°C, and the temperature was kept for 0.5-1.5h to obtain terminal alkyl hydrogen-containing polyorganosiloxane X7;

[0092] (2) 300 g of side hydrogen-containing polyorganosiloxane Me3SiO (MeHSiO) 35 (Me2SiO) 70 SiMe2(C 15 H 31) and 150g of α-octadecene were added to another reaction vessel, and 5ppm of platinum-vinyl complex was added when the temperature was raised to 50-80°C, and the temperature was raised to 120-200°C and kept warm for 0.5-1.5h to obtain pendant alkyl hydrogen-containing polyorganosiloxane Y7;

[0093] (3) Add 6 ppm of platinum-vinyl complex to 160 g of solid organosilicon powder D7, side alkyl hydrogen-containing polyorganosiloxane Y7, and terminal alkyl hydrogen-containing polyorganosiloxane X7 at a temperature of 50-80° C., raise the temperature to 110-180° C., and keep the temperature for 0.5-1.5 h;

[0094] (4) Add 30 g of MQ silicone resin (M:Q=1.1:1.0) to the mixture in (3), keep it at 100-160° C. for 1-5 hours, and cool it to room temperature to obtain an organosilicon defoaming composition.

[0095] Comparative Example 5-Adjustment of organosilicon solid powder

[0096] (1) 200g of hydrogen-terminated polyorganosiloxane Me2HSiO(Me2SiO) 200 SiHMe2 and 50g of α-octene were added to a reaction vessel, and when the temperature reached 50-80°C, 1ppm of chloroplatinic acid isopropanol solution was added and the temperature was kept for 0.5-1.5h to obtain terminal alkyl hydrogen-containing polyorganosiloxane X1;

[0097] (2) 400 g of side hydrogen-containing polyorganosiloxane Me2(C3H7)SiO(MeHSiO) 70 (Me2SiO) 50 SiMe2(C8H 17 ) and 100g of α-octene are added to another reaction container, and when the temperature is raised to 50-80°C, 1ppm of chloroplatinic acid isopropanol solution is added, and the temperature is raised to 120-200°C and kept warm for 0.5-1.5h to obtain a pendant alkyl hydrogen-containing polyorganosiloxane Y1;

[0098] (3) Add 1 ppm chloroplatinic acid isopropanol solution to 200 g of solid organosilicon powder D7, side alkyl hydrogenated polyorganosiloxane Y1, and terminal alkyl hydrogenated polyorganosiloxane X1 at a temperature of 50-80°C, and heat to 110-180°C for 0.5-1.5 h;

[0099] (4) Add 50 g of MQ silicone resin (M:Q=0.4:1.0) to the mixture in (3), keep it at 100-160° C. for 1-5 hours, and cool it to room temperature to obtain an organosilicon defoaming composition.

[0100] Comparative Example 6-Adjustment of organosilicon solid powder

[0101] (1) 300 g of hydrogen-terminated polyorganosiloxane Me2HSiO(Me2SiO) 32 SiHMe2 and 40 g of α-decene were added to a reaction vessel, and when the temperature reached 50-80°C, 2 ppm of a platinum-alcohol complex was added and the temperature was maintained for 0.5-1.5 h to obtain an alkyl-terminated hydrogen-containing polyorganosiloxane X2;

[0102] (2) 300 g of side hydrogen-containing polyorganosiloxane Me2(C6H5)SiO(MeHSiO) 100 (Me2SiO) 400 SiMe2(C 12 H 25 ) and 180g α-dodecene are added to another reaction container, and when the temperature is raised to 50-80°C, 2pp platinum-alcohol complex is added, and the temperature is raised to 120-200°C and kept warm for 0.5-1.5h to obtain pendant alkyl hydrogen-containing polyorganosiloxane Y2;

[0103] (3) Add 3 ppm of platinum-alcohol complex to 100 g of solid organosilicon powder D8, side alkyl hydrogen-containing polyorganosiloxane Y2, and terminal alkyl hydrogen-containing polyorganosiloxane X2 at a temperature of 50-80° C., raise the temperature to 110-180° C., and keep warm for 0.5-1.5 h;

[0104] (4) Add 80 g of MQ silicone resin (M:Q=0.6:1.0) to the mixture in (3), keep it at 100-160° C. for 1-5 hours, and cool it to room temperature to obtain an organosilicon defoaming composition.

[0105] Comparative Example 7-Adjustment of organosilicon solid powder

[0106] (1) 400 g of hydrogen-terminated polyorganosiloxane Me2HSiO(Me2SiO) 80 SiHMe2 and 30 g of α-tetradecene were added to a reaction vessel, and when the temperature reached 50-80°C, 3 ppm of a platinum-olefin complex was added and the temperature was maintained for 0.5-1.5 h to obtain an alkyl-terminated hydrogen-containing polyorganosiloxane X3;

[0107] (2) 200 g of side hydrogen-containing polyorganosiloxane Me2 (C6H 13 )SiO(MeHSiO) 17 (Me2SiO) 10 SiMe3 and 170 g of α-hexadecene were added to another reaction vessel, and when the temperature reached 50-80°C, 3 ppm of platinum-olefin complex was added. The temperature was raised to 120-200°C and kept warm for 0.5-1.5 h to obtain pendant alkyl hydrogen-containing polyorganosiloxane Y3.

[0108] (3) 180 g of solid organosilicon powder D9, side alkyl hydrogenated polyorganosiloxane Y3, and terminal alkyl hydrogenated polyorganosiloxane X3 were heated to 50-80° C., 4 ppm of platinum-olefin complex was added, and the temperature was raised to 110-180° C. and kept warm for 0.5-1.5 h;

[0109] (4) Add 20 g of MQ silicone resin (M:Q=0.8:1.0) to the mixture in (3), keep it at 100-160° C. for 1-5 hours, and cool it to room temperature to obtain an organosilicon defoaming composition.

[0110] Comparative Example 8-Adjustment of organosilicon solid powder

[0111] (1) 280 g of hydrogen-terminated polyorganosiloxane Me(C5H 11 )HSiO(Me2SiO) 10 SiHMe2 and 20 g of α-octadecene were added to a reaction vessel, and when the temperature reached 50-80°C, 5 ppm of a platinum-alkoxide complex was added and the temperature was maintained for 0.5-1.5 h to obtain an alkyl-terminated hydrogen-containing polyorganosiloxane X4;

[0112] (2) 230 g of side hydrogen-containing polyorganosiloxane Me3SiO (MeHSiO) 50 (Me2SiO) 100 SiMe2(C 18 H 37 ) and 300g α-eicosene are added to another reaction container, and when the temperature is raised to 50-80°C, 5ppm of platinum-alkoxide complex is added, and the temperature is raised to 120-200°C and kept warm for 0.5-1.5h to obtain pendant alkyl hydrogen-containing polyorganosiloxane Y4;

[0113] (3) Add 5 ppm of platinum-alkoxide complex to 100 g of solid organosilicon powder D10, side alkyl hydrogen-containing polyorganosiloxane Y4, and terminal alkyl hydrogen-containing polyorganosiloxane X4 at a temperature of 50-80° C., raise the temperature to 110-180° C., and keep warm for 0.5-1.5 h;

[0114] (4) Add 70 g of MQ silicone resin (M:Q=1.0:1.0) to the mixture in (3), keep the mixture at 100-160° C. for 1-5 hours, and cool it to room temperature to obtain an organosilicon defoaming composition.

[0115] Comparative Example 9 - Solid silicone powder replaced with hydrophobic silica

[0116] (1) 330 g of hydrogen-terminated polyorganosiloxane Me2HSiO(Me2SiO) 100SiHMe (C6H5) and 10 g of a C20-C24 linear α-olefin mixture were added to a reaction vessel. When the temperature reached 50-80°C, 6 ppm of a platinum-ether complex was added and the temperature was maintained for 0.5-1.5 h to obtain an alkyl-terminated hydrogen-containing polyorganosiloxane X5.

[0117] (2) 350 g of side hydrogen-containing polyorganosiloxane Me3SiO(C3H7HSiO) 10 (Me2SiO) 200 SiMe3 and 130 g of α-eicosene were added to another reaction vessel, and 6 ppm of platinum-ether complex was added when the temperature reached 50-80°C. The temperature was raised to 120-200°C and kept warm for 0.5-1.5 h to obtain pendant alkyl hydrogen-containing polyorganosiloxane Y5;

[0118] (3) 150g of hydrophobic white carbon black (specific surface area of ​​200m 2 / g), side alkyl hydrogen-containing polysiloxane Y5, terminal alkyl hydrogen-containing polysiloxane X5, add 8 ppm of platinum-ether complex when the temperature reaches 50-80 ° C, raise the temperature to 110-180 ° C, and keep warm for 0.5-1.5 h;

[0119] (4) Add 30 g of MQ silicone resin (M:Q=1.2:1.0) to the mixture in (3), keep it at 100-160° C. for 1-5 hours, and cool it to room temperature to obtain an organosilicon defoaming composition.

[0120] Example 14-Example 25

[0121] According to the solid defoamer preparation technology known in the art, the organosilicon defoamer compositions prepared in Examples 7 to 13 and the organosilicon defoamer compositions prepared in Comparative Examples 5 to 9 were used to prepare solid defoamers G1 to G7 and DG1 to DG5, respectively. The preparation methods are as follows:

[0122] 20 g of the organosilicon defoaming composition, 12 g of polyacrylic acid polymer and 10 g of dodecylbenzenesulfonic acid were mixed evenly, and then 158 g of modified starch and 20 g of water were added and mixed evenly. After granulation, the mixture was dried at 120° C. for 0.5 h to obtain a solid defoaming agent.

[0123] Example 26 to Example 37

[0124] According to the well-known emulsion defoamer preparation technology in the technical field, the organosilicon defoamer compositions prepared in Examples 7 to 13 and the organosilicon defoamer compositions prepared in Comparative Examples 5 to 9 were used to prepare liquid defoamers Y1 to Y7 and DY1 to DY5, respectively. The preparation methods are as follows:

[0125] 100 g of an organosilicon defoaming composition, 30 g of sorbitan monostearate (Span 60) and 20 g of polyoxyethylene (20) sorbitan monostearate were mixed at 70° C. for 10 minutes, and 500 g of water was added in batches; then 2 g of polyacrylic acid was added to the mixture, and the pH was adjusted to 6-7 with 10% NaOH, followed by the addition of 345 g of water; finally, the emulsion was homogenized with a high-pressure homogenizer, and the pH was again adjusted to 6-7 with 10% NaOH, and then 3 g of an isothiazolinone-based preservative was added to obtain an emulsion defoaming agent.

[0126] Defoamer performance test

[0127] The organosilicon defoaming composition prepared in this invention can be prepared into solid and liquid defoamers, demonstrating excellent foam reduction and suppression performance in applications such as papermaking and pulping, textile printing and dyeing, oil extraction, daily chemical cleaning, and industrial cleaning. The following tests were conducted using laundry detergent, papermaking black liquor, and textile pulp.

[0128] Solid defoamer performance test

[0129] This test uses a Jinzhang drum washing machine, model: ZWH6125, with a capacity of 7kg.

[0130] Test method: Add 150g of commercially available laundry detergent, 0.75g of solid defoaming agent and 20kg of water into the washing machine. The test procedure is the cotton and linen procedure. There are 5 measurement marks on the window of the washing machine, namely 0, 25%, 50%, 75% and 100% of the window height. "0" is the starting point, indicating no foam, and "100%" indicates full foam. Record the foam height every 5 minutes and record it when the machine is stopped. The larger the value, the higher the foam scale value in the washing machine, and the worse the anti-foaming performance; the lower the foam scale value in the same time, the better the anti-foaming performance of the product. The test results are shown in Table 1:

[0131] Table 1 Washing machine test results

[0132] As can be seen from Table 1, the solid defoamers G1 to G7 prepared using the organosilicon defoaming compositions prepared in Examples 7 to 13 have better foam removal and suppression performance in machine washing in a detergent solution than the solid defoamers YG1 to YG5 prepared using the organosilicon defoaming compositions of Comparative Examples 5 to 9, and have good anti-attenuation performance in the later stage.

[0133] Emulsion defoamer performance test

[0134] Test 1: Papermaking black liquor system tested at 85°C

[0135] Test method: First, add 600mL of black liquor (derived from pine wood) to the circulating bubbler, set the temperature to 85°C, and the flow rate to 6L / min. Then, turn on the temperature control switch, heat the foaming liquid to the set temperature, start the circulation pump, and begin impact foaming. When the foam rises to 300mL, add 0.1% defoamer and record the change in foam height over time. The better the defoaming performance of the defoamer, the lower the minimum scale mark the foam reaches; the better the defoamer's anti-foaming performance, the longer it takes for the foam to return to 300mL.

[0136] Table 2 Test results of black liquor system at 85℃

[0137] As can be seen from Table 2, the liquid defoamers G1 to G7 prepared using the organosilicon defoaming compositions prepared in Examples 7 to 13 have better foam removal and suppression performance in black liquor than the liquid defoamers YG1 to YG5 prepared using the organosilicon defoaming compositions of Comparative Examples 5 to 9, and have good anti-attenuation performance in the later stage.

[0138] Test 2: Textile Slurry Test

[0139] Test method: Add 160ml of prepared textile pulp to a 250ml stoppered graduated cylinder, then add 0.05g of emulsion defoamer. Shake the flask up and down at a speed of 2 seconds per shake. Shake each flask 10 times and record the defoaming time for each group. The shorter the defoaming time in each group, the better the defoaming and antifoaming performance of the defoamer sample.

[0140] Table 3 Slurry system test

[0141] As can be seen from Table 3, the liquid defoamers G1 to G7 prepared using the organosilicon defoaming compositions prepared in Examples 7 to 13 have better defoaming and anti-foaming performance in textile slurry than the liquid defoamers YG1 to YG5 prepared using the organosilicon defoaming compositions of Comparative Examples 5 to 9, and have good anti-attenuation performance in the later stage.

Claims

1. An organosilicon defoaming composition, characterized in that It is composed of the following substances: A. Hydrogen-terminated polyorganosiloxane At least one of the general structural formulas is as follows: R 0 2HSiO(Me2SiO) a SiHR 0 2 In the formula, the substituent R 0 The same or different, is a hydrocarbon group with 1 to 12 carbon atoms, selected from alkyl, cycloalkyl, aryl, wherein the alkyl is selected from methyl, ethyl, n-propyl, n-butyl, isobutyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, isooctyl, n-nonyl, n-decyl, n-dodecyl; the cycloalkyl is selected from cyclopentyl and cyclohexylethyl; the aryl is selected from phenyl, benzyl, phenethyl, 2-phenylpropyl; the subscript a is an integer of 10 to 200; the amount thereof is 20-40% of the total mass of the defoaming composition; B. Side-containing hydrogen polysiloxane At least one of the following general structural formulas: Me3SiO(R 1 HSiO) b (R 1 2SiO) c SiMe3 In the formula, the substituent R 1 The same or different, is a hydrocarbon group with 1 to 18 carbon atoms, selected from alkyl, cycloalkyl, aryl, wherein the alkyl is selected from methyl, ethyl, n-propyl, n-butyl, isobutyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, isooctyl, n-nonyl, n-decyl, n-dodecyl and n-octadecyl; the cycloalkyl is selected from cyclopentyl and cyclohexylethyl; the aryl is selected from phenyl, benzyl, phenethyl and 2-phenylpropyl; the subscript b is an integer of 10 to 100; the subscript c is an integer of 10 to 400; the amount thereof is 20-40% of the total mass of the defoaming composition; C. α-olefins The α-olefin is any one or more mixtures of linear α-olefins, α-aromatic olefins or branched α-olefins, including α-octene, α-decene, α-dodecene, α-tetradecene, α-hexadecene, α-octadecene, α-eicosene, a C20-C24 linear α-olefin mixture, a C24-C28 linear α-olefin mixture, α-triacontene, α-methylstyrene, and α-styrene, which can be used alone or mixed in any proportion; the α-olefin is added in two parts, the first part is used in an amount of 1-5% of the total mass of the defoaming composition, and the second part is used in an amount of 10-30% of the total mass of the defoaming composition; D. Solid silicone powder The solid organosilicon powder is formed by reacting a high hydrogen-containing polyorganosiloxane D1 and a high vinyl content vinyl polysiloxane D2 under the action of a platinum catalyst D3, and finally ground to obtain a solid organosilicon powder, the amount of which is 10-20% of the total mass of the defoaming composition; the hydrogen content of the high hydrogen-containing polyorganosiloxane is ≥0.1%; the molecular weight of the high vinyl content vinyl polysiloxane D2 is <10000; E. Catalyst The catalyst is selected from platinum-alcohol complex, platinum-olefin complex, platinum-alkoxide complex, platinum-ether complex, platinum-ketone complex, chloroplatinic acid isopropanol solution, platinum-vinyl complex, preferably chloroplatinic acid isopropanol solution; the amount of the catalyst is 3-20 ppm (in terms of platinum) of the total mass of the terminal hydrogen-containing polyorganosiloxane A, the side hydrogen-containing polyorganosiloxane B, the α-olefin C and the solid organosilicon powder D, and is used in three parts; F.MQ Silicone Resin The MQ silicone resin is composed of chain segments (CH3)3SiO l / 2 (M unit) and chain SiO 4 / 2 The MQ resin composed of (Q unit) has a molar ratio of (0.4-1.2):1.0, and the amount used is 2-8% of the total mass of the defoaming composition.

2. The organosilicon defoaming composition according to claim 1, characterized in that: The hydrogen-terminated polyorganosiloxane R 0 It is methyl.

3. The organosilicon defoaming composition according to claim 1, characterized in that: The side hydrogen-containing polyorganosiloxane is selected from R 1 It is methyl.

4. The organosilicon defoaming composition according to claim 1, characterized in that: The general structural formula of the high hydrogen-containing polyorganosiloxane D1 in the solid organosilicon powder is as follows: c R 3 3-c SiO(SiR 3 HO) d (SiR 3 2O) b S i 3 3-c H c R 3 are alkyl groups with 1 to 5 carbon atoms, which are the same or different; subscript c is 0, 1 or 2, subscript d is an integer of 100 to 300; subscript b is an integer of 50 to 1600; and the amount used accounts for 10 to 30% of the total mass of the solid organosilicon powder.

5. The organosilicon defoaming composition according to claim 1, characterized in that: The general structural formula of the high vinyl content vinyl polysiloxane D2 in the solid organosilicon powder is as follows: e R 4 3-e SiO(SiR 4 ViO) f (SiR 4 2O) g S i 4 3-e Vi e R 4 The value range is similar to R 3 The same; Vi is vinyl, subscript e is 0 or 1, subscript f is 30-80; subscript g is 20-80; the amount is 70-90% of the total mass of the solid organosilicon powder.

6. The organosilicon defoaming composition according to claim 1, characterized in that: The platinum catalyst D3 in the solid organosilicon powder is selected from platinum-alcohol complex, platinum-olefin complex, platinum-alkoxide complex, platinum-ether complex, platinum-ketone complex, chloroplatinic acid isopropanol solution, and platinum-vinyl complex; the amount used accounts for 0.01%-0.05% of the total mass of high hydrogen-containing polysiloxane and high vinyl content vinyl polysiloxane.

7. The organosilicon defoaming composition according to any one of claims 1 to 6, wherein the preparation method thereof is as follows: (1) adding a terminal hydrogen-containing polyorganosiloxane A and a first portion of an α-olefin into a reaction vessel, adding a catalyst when the temperature rises to 50-80° C., and maintaining the temperature for 0.5-1.5 hours to obtain a terminal alkyl hydrogen-containing polyorganosiloxane X; (2) adding the side hydrogen-containing polyorganosiloxane B and the second part of the α-olefin into another reaction container, adding the catalyst when the temperature rises to 50-80° C., raising the temperature to 120-200° C., and keeping the temperature for 0.5-1.5 hours to obtain the side alkyl hydrogen-containing polyorganosiloxane Y; (3) adding a catalyst to solid organosilicon powder D, side alkyl hydrogen-containing polyorganosiloxane Y, and terminal alkyl hydrogen-containing polyorganosiloxane X at a temperature of 50 to 80° C., raising the temperature to 110 to 180° C., and keeping the temperature for 0.5 to 1.5 hours; (4) Add MQ silicone resin to the mixture in (3), keep the mixture at 100-160° C. for 1-5 hours, and cool it to room temperature to obtain an organosilicon defoaming composition.

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