Efficient defoaming block, preparation method and application thereof

Abstract

The scheme belongs to the technical field of defoaming agents, and aims to solve the problems of frequent addition and difficult dosage control of traditional defoaming agents, and provides a kind of efficient defoaming block, a preparation method and application thereof. A polyurethane foaming sponge is used as a carrier to load a defoaming agent containing a silicon polyether copolymer and a composite functional material of hydroxyl-terminated polybutadiene and activated silicon dioxide, and the defoaming block is prepared through vacuum impregnation and gradient heating. The silicon polyether copolymer breaks the bubbles quickly, the hydroxyl-terminated polybutadiene is crosslinked with the silicon polyether copolymer to form a network for controlled release, the activated silicon dioxide enhances the network through crosslinking and adsorbs foaming substances, and the stabilizer is used to improve the environmental durability, so that the components and the process are synergistic to realize efficient defoaming and long-acting slow release.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of defoaming agents, in particular to a high-efficiency defoaming block, a preparation method and application thereof. BACKGROUND

[0002] Defoaming technology is widely used in chemical industry, food industry, pharmaceutical industry, water treatment, washing and other fields. Defoaming agents are traditionally used to defoam in different scenarios. Common defoaming agents include organosilicon, polyether and silicon-polyether polymer. Among them, the silicon-polyether polymer defoaming agent has a unique molecular structure, combines the high-efficiency defoaming ability of organosilicon defoaming agent and the good compatibility of polyether defoaming agent, and performs particularly outstanding in defoaming performance. It can not only quickly inhibit the generation of foam, but also stably play a role in a wide temperature and pH range and harsh working conditions, has good adaptability to water-based and oil-based systems, and is stable in chemical properties, low in volatility, good in biocompatibility, and can effectively improve production efficiency and product quality when applied in food, medicine, chemical industry, papermaking and other industries, without residues and side effects. However, defoaming agents need to be frequently added, and in actual application, due to the complexity and uncertainty of foam generation, it is difficult to accurately control the optimal amount of defoaming agent. SUMMARY

[0003] In view of the deficiencies of the prior art, the present application provides a high-efficiency defoaming block, a preparation method and application thereof. A polyurethane foaming sponge is used as a carrier to load a defoaming agent containing a silicon-polyether copolymer and a composite functional material of hydroxyl-terminated polybutadiene and activated silicon dioxide, and the defoaming block is prepared by vacuum impregnation and gradient heating. The silicon-polyether copolymer quickly breaks the foam, the hydroxyl-terminated polybutadiene is crosslinked with the silicon-polyether copolymer to form a network for controlled release, the activated silicon dioxide enhances the network by crosslinking and adsorbs foaming substances, and the stabilizer improves environmental durability, so that the components and process are synergistic to achieve high-efficiency defoaming and long-acting controlled release.

[0004] To achieve the above-mentioned purposes, the present application adopts the following technical solutions:

[0005] In a first aspect, the present application provides a high-efficiency defoaming block, which comprises a porous material carrier, a defoaming agent and a composite functional material. The defoaming agent and the composite functional material are loaded inside and on the surface of the porous material carrier after vacuum impregnation and gradient heating. The defoaming agent comprises a silicon-polyether copolymer, a thermal initiation crosslinking agent, an ultraviolet absorber, an antioxidant and an anti-hydrolysis agent. The silicon-polyether copolymer is obtained by reaction of dimethyl polysiloxane, polyethylene glycol and a catalyst. The composite functional material comprises hydroxyl-terminated polybutadiene, activated silicon dioxide and ethyl acetate. The activated silicon dioxide is prepared by modifying ethylene-vinyl-grafted silicon dioxide with silane.

[0006] In one feasible implementation, the defoamer is mixed with toluene at a mass ratio of (2-3):(7-8) to prepare a defoamer solution, wherein the volume ratio of the defoamer solution, the composite functional material, and the porous material carrier is (0.4-0.45):0.4:1; the mass ratio of the silicone polyether copolymer, the thermally initiated crosslinking agent, the ultraviolet absorber, the antioxidant, and the anti-hydrolysis agent is 100:(12.5-16.7):(8-12):(5-7):(1-1.5); the mass ratio of the dimethyl polysiloxane, polyethylene glycol, and the catalyst is 2:(2.9-3.1):0.05; and the mass ratio of the hydroxyl-terminated polybutadiene, the activated silica, and the ethyl acetate is (5-10):(9-11):100.

[0007] In one feasible implementation, the porous material carrier is polyurethane foam sponge with a density of 18–75 kg / m³. 3 The pore size is 25-60 PPI; the catalyst is stannous octoate; the thermally initiated crosslinking agent is benzoyl peroxide; the ultraviolet absorber is UV-531; the anti-hydrolysis agent is carbodiimide; and the antioxidant is antioxidant 1010.

[0008] The three-dimensional porous structure (25-60 PPI) of polyurethane foam provides a high specific surface area and abundant pore size, serving as a "storage-release" carrier for defoamers.

[0009] Secondly, this application provides a method for preparing a high-efficiency defoaming block, comprising the following steps:

[0010] S1. A silicone polyether copolymer is prepared in a nitrogen atmosphere using dimethyl polysiloxane, polyethylene glycol, and a catalyst; the silicone polyether copolymer, a thermally initiated crosslinking agent, a UV absorber, an antioxidant, and an anti-hydrolysis agent are mixed to obtain an antifoaming agent; the antifoaming agent is mixed with toluene to obtain an antifoaming agent solution; a silane hydrolysate is prepared using vinyltrimethoxysilane; silica is added to the silane hydrolysate, and the reaction yields vinyl-grafted silica; the vinyl-grafted silica is reacted with a first silane coupling agent to obtain activated silica; a composite functional material is obtained by mixing hydroxyl-terminated polybutadiene, the activated silica, and ethyl acetate.

[0011] S2. Cut the polyurethane foam sponge into a set shape, place it in a vacuum pressure impregnation tank, evacuate the vacuum, add the defoamer solution and the composite functional material, and introduce nitrogen gas to obtain an impregnated defoaming block. Spray the residual defoamer solution and residual composite functional material in the vacuum pressure impregnation tank onto the surface of the impregnated defoaming block to obtain a defoaming block precursor.

[0012] S3. The defoaming block precursor is subjected to gradient heating to obtain a cross-linked defoaming block. The cross-linked defoaming block is treated with a second silane coupling agent to obtain a silane-modified defoaming block. After treatment under set conditions, the high-efficiency defoaming block is obtained.

[0013] In one feasible implementation, the preparation of the silicone polyether copolymer in S1 includes: mixing dimethyl polysiloxane, polyethylene glycol, and a catalyst in a nitrogen atmosphere, followed by a first-stage heating and a second-stage heating. The first-stage heating involves raising the reaction system to 70-75°C at a rate of 1.5°C / min and maintaining the temperature for 40-50 min. The second-stage heating involves raising the temperature of the system after the first-stage heating to 112-118°C at a rate of 1°C / min and maintaining the reaction for 5-6 h. The defoamer is mixed with toluene and stirred at 60-80°C to dissolve it, thus obtaining the defoamer solution.

[0014] Dimethyl polysiloxane and the hydroxyl groups of polyethylene glycol (PEG) undergo a condensation reaction under the catalysis of stannous octoate to form Si-OC bonds, generating a silicone polyether block copolymer. Stannous octoate reduces the activation energy of hydroxyl condensation through coordination effect, promoting the dehydration condensation reaction. The silicone polyether copolymer combines the low surface tension of polysiloxane (rapid spreading and defoaming) and the hydrophilicity of polyether (improved compatibility with aqueous phase). The silicon-oxygen segments in its molecular structure can be rapidly adsorbed onto the surface of the foam liquid film, reducing the surface tension and causing the liquid film to rupture. Meanwhile, the polyether segments stabilize the dispersion of the copolymer in the aqueous phase through hydrogen bonding, preventing agglomeration and deactivation.

[0015] In one feasible implementation, the silane hydrolysate in S1 is obtained by adding glacial acetic acid and deionized water to an ethanol solution of vinyltrimethoxysilane and then hydrolyzing it at room temperature for 1.5–2.5 h. The concentration of the ethanol solution of vinyltrimethoxysilane is 4 wt%–6 wt%, and the volume ratio of the ethanol solution of vinyltrimethoxysilane, glacial acetic acid, and deionized water is 10:(0.1–0.2):(0.9–1.1). The reaction temperature for preparing the vinyl-grafted silica is 75–85 °C, and the reaction time is 5–7 h.

[0016] Vinyltrimethoxysilane (VTMO) hydrolyzes under acidic conditions (adjusted by glacial acetic acid) to generate silanol. The silanol condenses with the hydroxyl groups on the surface of silica to form Si-O-Si bonds. The thiol (-SH) group of γ-mercaptopropyltrimethoxysilane (MPTMS) undergoes a free radical addition reaction with the double bond of vinyl-grafted silica, introducing thiol active sites and grafting vinyl onto the silica surface.

[0017] In one feasible implementation, the first silane coupling agent is γ-mercaptopropyltrimethoxysilane, and the preparation of the activated silica includes mixing vinyl-grafted silica with γ-mercaptopropyltrimethoxysilane and toluene at a mass ratio of (9-11):1:50 and reacting at 45-55°C for 1.5-2.5 h; the composite functional material is obtained by sonication for 60-90 min.

[0018] The hydroxyl groups of hydroxyl-terminated polybutadiene (HTPB) interact with the thiol and silanol groups on the surface of activated silica through hydrogen bonds and van der Waals forces, forming a physically entangled structure. Ultrasonic dispersion breaks down the aggregates through cavitation, promoting uniform dispersion of silica within the HTPB matrix. HTPB, as a flexible segment, forms an elastic network after crosslinking with the silicone polyether copolymer. The network pores allow the silicone polyether copolymer to diffuse rapidly to the foam surface in the initial stage; simultaneously, the network elasticity prevents excessive copolymer loss, regulating the release rate of the defoamer and achieving long-lasting foam suppression. The vinyl and thiol groups on the surface of activated silica can copolymerize with the silicone polyether copolymer and hydroxyl-terminated polybutadiene, forming crosslinking points and enhancing the density of the material network. At the same time, the high specific surface area of ​​silica can adsorb surfactants in the foam liquid film, disrupting the stability of the liquid film and synergistically accelerating foam defoaming with the silicone polyether copolymer.

[0019] In one feasible implementation, nitrogen gas is introduced into the vacuum pressure impregnation tank in S2 to 0.5 MPa and maintained for 20-30 minutes to obtain the impregnated defoaming block; the impregnated defoaming block is rotated at a speed of 110-130 r / min, and the residual defoamer solution and residual composite functional material are sprayed with a spray gun at a pressure of 0.3-0.4 MPa and a distance of 15-20 cm to obtain the defoaming block precursor.

[0020] Vacuuming removes air from the pores of the polyurethane foam, creating a negative pressure difference; pressurization (0.5MPa nitrogen) causes the defoamer solution and composite functional materials to penetrate deep into the pores through capillary action, completing the load.

[0021] In one feasible implementation, the gradient heating in S3 includes a first gradient and a second gradient. The heating rate of the first gradient is 0.6℃ / min, heating to 50-60℃, and holding for 1.5-2.5h. The heating rate of the second gradient is 0.3℃ / min, heating to 75-80℃, and holding for 3-4h. The second silane coupling agent is KH-560. The preparation of the silane-modified defoaming block includes: immersing the crosslinked defoaming block in a 3%-4% KH-560 ethanol solution for 45-60min, and drying to obtain the silane-modified defoaming block. The set conditions for the treatment of the silane-modified defoaming block are 70-80℃, relative humidity 63%-68%, and treatment time 60-72h.

[0022] Benzoyl peroxide (BPO) decomposes at 75-80℃ to generate benzoyl oxygen free radicals, which initiate free radical copolymerization reactions of the vinyl groups of silicone polyether copolymer, the double bonds of HTPB, and the thiol groups of activated silica, forming a three-dimensional cross-linked network. This prevents the defoamer from dissolving and leaching out during use, and improves the mechanical strength of the material. The network pore size limits the diffusion rate of the silicone polyether copolymer, maintaining long-lasting defoaming effect.

[0023] After hydrolysis, KH-560 (γ-glycidyl etheroxypropyltrimethoxysilane) condenses with the hydroxyl groups on the surface of the cross-linked network to form a dense protective film. At 70-80℃, the incompletely cross-linked groups react further, releasing the internal thermal stress of the material and increasing the degree of cross-linking. The protective film isolates moisture, oxygen and ultraviolet rays. UV-531 ultraviolet absorber and antioxidant 1010 capture free radicals, and carbodiimide, an anti-hydrolysis agent, neutralizes trace amounts of carboxylic acid and inhibits material degradation. Thermal aging homogenizes the cross-linked network and reduces the rate of defoaming efficiency decline.

[0024] Thirdly, this application provides an application of a high-efficiency defoaming block in the field of defoaming.

[0025] Beneficial technical effects:

[0026] This solution discloses a high-efficiency defoaming block, its preparation method, and its application. Polyurethane foam is used as a porous material carrier, loaded with a defoamer containing a silicone polyether copolymer and a composite functional material composed of hydroxyl-terminated polybutadiene and activated silica. Upon contact with the foam, the silicone polyether copolymer rapidly spreads on the liquid film surface, reducing surface tension and causing the liquid film to rupture, thus achieving rapid defoaming. The hydroxyl-terminated polybutadiene and the silicone polyether copolymer form a block copolymer through the condensation reaction of hydroxyl groups and silicon-oxygen bonds. Under the action of a thermally initiated crosslinking agent, its unsaturated double bonds undergo copolymerization and addition reactions with vinyl-containing silica, constructing a crosslinked network. This network not only enhances the adhesion stability of the defoamer within the pores of the polyurethane foam but also achieves slow release of the defoamer by physically blocking and regulating the molecular diffusion rate, thus prolonging the foam suppression time. The vinyl-containing silica, on the one hand, enhances the network density by forming covalent bonds between surface vinyl groups and the silicone polyether copolymer; on the other hand, it utilizes the high specific surface area of ​​nanoparticles to adsorb foaming substances, thereby disrupting foam stability. The high-efficiency defoaming block prepared by this invention has both high-efficiency defoaming ability and long-lasting sustained-release performance. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the preparation method of the high-efficiency defoaming block of the present invention.

[0028] Figure 2 This is a physical image of the high-efficiency defoaming block prepared in Example 1 of the present invention. Detailed Implementation

[0029] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the application will be further described in detail below with reference to embodiments. However, this should not be construed as limiting the scope of this application to the following examples. All other embodiments obtained by those skilled in the art without creative effort without departing from the above-described methodological spirit of this application are within the scope of protection of this application.

[0030] In this application, the terminology used is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0031] The singular forms “for,” “or,” “a,” “any,” and “the” used in this application are intended to include the plural forms unless the context clearly indicates otherwise.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] The following will describe in detail, with reference to different embodiments, a high-efficiency defoaming block, its preparation method and application.

[0034] Example 1

[0035] like Figure 1 As shown, a method for preparing a high-efficiency defoaming block includes the following steps:

[0036] 1. Under nitrogen protection, dimethyl polysiloxane, polyethylene glycol, and stannous octoate were mixed in a mass ratio of 2:3:0.05, heated to 72°C at a rate of 1.5°C / min, held for 45 min, then heated to 115°C at a rate of 1°C / min, and maintained for 5.5 h. The mixture was then distilled under reduced pressure to obtain a silicone polyether copolymer. The silicone polyether copolymer, thermally initiating crosslinking agent benzoyl peroxide, ultraviolet absorber UV-531, antioxidant 1010, and anti-hydrolysis agent carbodiimide were mixed in a mass ratio of 100:14.6:10:6:1.2 to obtain an antifoaming agent. The antifoaming agent was mixed with toluene in a mass ratio of 2.5:7.5 and stirred at 70°C until completely dissolved to obtain an antifoaming agent solution.

[0037] 2. Glacial acetic acid was added dropwise to a 5 wt% vinyltrimethoxysilane ethanol solution, followed by deionized water. The volume ratio of the vinyltrimethoxysilane ethanol solution, glacial acetic acid, and deionized water was 10:0.15:1. Hydrolysis was carried out at room temperature for 2 hours to obtain a silane hydrolysate. Silica was added to the silane hydrolysate, refluxed at 80°C for 6 hours, centrifuged, and the solid was washed with ethanol and dried to obtain vinyl-grafted silica. Vinyl-grafted silica was mixed with γ-mercaptopropyltrimethoxysilane and toluene at a mass ratio of 10:1:50, reacted at 50°C for 2 hours, centrifuged, washed with toluene, and dried to obtain activated silica. Hydroxyl-terminated polybutadiene, activated silica, and ethyl acetate were mixed at a mass ratio of 8:10:100 and ultrasonically dispersed for 75 minutes to form a composite functional material.

[0038] 3. The density is 40 kg / m³ 3 Polyurethane foam with a pore size of 45 PPI was cut into 5 cm × 18 cm × 1 cm blocks and placed in a vacuum pressure impregnation tank. The vacuum was evacuated to 0.098 MPa and maintained for 25 min. Defoamer solution and composite functional material were injected. The volume ratio of defoamer solution, composite functional material and porous material carrier was 0.42:0.4:1. Nitrogen gas was introduced to 0.5 MPa and maintained for 25 min to obtain impregnated defoaming blocks. The impregnated defoaming blocks were removed and placed in a rotary spraying device. The device was rotated at a speed of 120 r / min. The residual defoamer solution and residual composite functional material in the vacuum pressure impregnation tank were sprayed onto the surface of the impregnated defoaming blocks at a pressure of 0.35 MPa and a distance of 18 cm using a high-pressure spray gun to obtain the defoaming block precursor.

[0039] 4. The defoaming block precursor was heated to 55℃ at a rate of 0.6℃ / min and held for 2 hours, then heated to 78℃ at a rate of 0.3℃ / min and held for 3.5 hours to obtain a cross-linked defoaming block. The cross-linked defoaming block was immersed in an ethanol solution of 3.5% silane coupling agent KH-560 for 55 minutes, air-dried at room temperature, and then dried at 45℃ for 3 hours to obtain a silane-modified defoaming block. The silane-modified defoaming block was treated at 75℃ and 65% relative humidity for 66 hours to obtain the desired product. Figure 2 The high-efficiency defoaming block shown.

[0040] Example 2

[0041] like Figure 1 As shown, a method for preparing a high-efficiency defoaming block includes the following steps:

[0042] 1. Under nitrogen protection, dimethyl polysiloxane, polyethylene glycol, and stannous octoate were mixed in a mass ratio of 2:2.9:0.05, heated to 70°C at a rate of 1.5°C / min, held for 50 min, then heated to 112°C at a rate of 1°C / min, maintained for 6 h, and distilled under reduced pressure to obtain a silicone polyether copolymer; the silicone polyether copolymer, thermally initiating crosslinking agent benzoyl peroxide, ultraviolet absorber UV-531, antioxidant 1010, and anti-hydrolysis agent carbodiimide were mixed in a mass ratio of 100:12.5:12:5:1 to obtain an antifoaming agent; the antifoaming agent was mixed with toluene in a mass ratio of 2:8, and stirred at 70°C until completely dissolved to obtain an antifoaming agent solution;

[0043] 2. Glacial acetic acid was added dropwise to a 4 wt% vinyltrimethoxysilane ethanol solution, followed by deionized water. The volume ratio of vinyltrimethoxysilane ethanol solution, glacial acetic acid, and deionized water was 10:0.1:1.1. Hydrolysis was carried out at room temperature for 1.5 h to obtain a silane hydrolysate. Silica was added to the silane hydrolysate, refluxed at 75 °C for 7 h, centrifuged, and the solid was washed with ethanol and dried to obtain vinyl-grafted silica. Vinyl-grafted silica was mixed with γ-mercaptopropyltrimethoxysilane and toluene at a mass ratio of 9:1:50, reacted at 45 °C for 2.5 h, centrifuged, washed with toluene, and dried to obtain activated silica. Hydroxyl-terminated polybutadiene, activated silica, and ethyl acetate were mixed at a mass ratio of 5:11:100 and ultrasonically dispersed for 60 min to form a composite functional material.

[0044] 3. The density is 18 kg / m³ 3 Polyurethane foam with a pore size of 60 PPI was cut into 5 cm × 18 cm × 1 cm blocks and placed in a vacuum pressure impregnation tank. The vacuum was evacuated to 0.098 MPa and maintained for 25 min. Defoamer solution and composite functional material were injected. The volume ratio of defoamer solution, composite functional material and porous material carrier was 0.4:0.4:1. Nitrogen gas was introduced to 0.5 MPa and maintained for 20 min to obtain impregnated defoaming blocks. The impregnated defoaming blocks were removed and placed in a rotary spraying device. The device was rotated at a speed of 110 r / min. The residual defoamer solution and residual composite functional material in the vacuum pressure impregnation tank were sprayed onto the surface of the impregnated defoaming blocks at a pressure of 0.3 MPa and a distance of 15 cm using a high-pressure spray gun to obtain the defoaming block precursor.

[0045] 4. The defoaming block precursor was heated to 50℃ at 0.6℃ / min and held for 2.5h, then heated to 75℃ at 0.3℃ / min and held for 4h to obtain a cross-linked defoaming block; the cross-linked defoaming block was immersed in an ethanol solution of 3% silane coupling agent KH-560 for 60min, air-dried at room temperature, and then dried at 45℃ for 3h to obtain a silane-modified defoaming block; the silane-modified defoaming block was treated at 70℃ and 63% relative humidity for 72h to obtain a high-efficiency defoaming block.

[0046] Example 3

[0047] like Figure 1 As shown, a method for preparing a high-efficiency defoaming block includes the following steps:

[0048] 1. Under nitrogen protection, dimethyl polysiloxane, polyethylene glycol, and stannous octoate were mixed in a mass ratio of 2:3.1:0.05, heated to 75°C at a rate of 1.5°C / min, held for 40 min, then heated to 118°C at a rate of 1°C / min, maintained for 5 h, and distilled under reduced pressure to obtain a silicone polyether copolymer; the silicone polyether copolymer, thermally initiating crosslinking agent benzoyl peroxide, ultraviolet absorber UV-531, antioxidant 1010, and anti-hydrolysis agent carbodiimide were mixed in a mass ratio of 100:16.7:8:7:1.5 to obtain an antifoaming agent; the antifoaming agent was mixed with toluene in a mass ratio of 3:7, and stirred at 80°C until completely dissolved to obtain an antifoaming agent solution;

[0049] 2. Glacial acetic acid was added dropwise to a 6 wt% vinyltrimethoxysilane ethanol solution, followed by deionized water. The volume ratio of the vinyltrimethoxysilane ethanol solution, glacial acetic acid, and deionized water was 10:0.2:0.9. The solution was hydrolyzed at room temperature for 2.5 h to obtain a silane hydrolysate. Silica was added to the silane hydrolysate, refluxed at 85 °C for 5 h, centrifuged, and the solid was washed with ethanol and dried to obtain vinyl-grafted silica. Vinyl-grafted silica was mixed with γ-mercaptopropyltrimethoxysilane and toluene at a mass ratio of 11:1:50, reacted at 55 °C for 1.5 h, centrifuged, washed with toluene, and dried to obtain activated silica. Hydroxyl-terminated polybutadiene, activated silica, and ethyl acetate were mixed at a mass ratio of 10:9:100 and ultrasonically dispersed for 90 min to form a composite functional material.

[0050] 3. The density is 75 kg / m³ 3 Polyurethane foam with a pore size of 25 PPI was cut into 5 cm × 18 cm × 1 cm blocks and placed in a vacuum pressure impregnation tank. The vacuum was evacuated to 0.098 MPa and maintained for 25 min. Defoamer solution and composite functional material were injected. The volume ratio of defoamer solution, composite functional material and porous material carrier was 0.45:0.4:1. Nitrogen gas was introduced to 0.5 MPa and maintained for 30 min to obtain impregnated defoaming blocks. The impregnated defoaming blocks were removed and placed in a rotary spraying device. The device was rotated at a speed of 130 r / min. The residual defoamer solution and residual composite functional material in the vacuum pressure impregnation tank were sprayed onto the surface of the impregnated defoaming blocks at a pressure of 0.4 MPa and a distance of 20 cm using a high-pressure spray gun to obtain the defoaming block precursor.

[0051] 4. The defoaming block precursor was heated to 60℃ at 0.6℃ / min and held for 1.5h, then heated to 80℃ at 0.3℃ / min and held for 3h to obtain a cross-linked defoaming block; the cross-linked defoaming block was immersed in an ethanol solution of 4% silane coupling agent KH-560 for 45min, air-dried at room temperature, and then dried at 45℃ for 3h to obtain a silane-modified defoaming block; the silane-modified defoaming block was treated at 80℃ and 68% relative humidity for 60h to obtain a high-efficiency defoaming block.

[0052] Comparative Example 1

[0053] A method for preparing a high-efficiency defoaming block is implemented with the same steps and parameters as in Example 1, except that hydroxyl-terminated polybutadiene is not added.

[0054] Comparative Example 2

[0055] A method for preparing a high-efficiency defoaming block is implemented with the same steps and parameters as in Example 1, except that the silica is not subjected to vinyl grafting and silane modification treatment, and the activated silica is replaced with silica.

[0056] Comparative Example 3

[0057] A method for preparing a high-efficiency defoaming block is implemented with the same steps and parameters as in Example 1, except that the traditional atmospheric pressure immersion method is used instead of vacuum pressure impregnation.

[0058] Performance testing:

[0059] 1. Defoaming performance:

[0060] To prepare a standard foaming solution, dissolve 5g of nonylphenol polyoxyethylene ether (NP-10) and 5g of sodium dodecylbenzene sulfonate (SDBS) in 990mL of deionized water and stir until homogeneous and transparent. Take 500mL of the standard foaming solution into a stoppered graduated cylinder and keep it at 25°C. Add 0.2g of the high-efficiency defoaming block prepared in Examples 1-3 and Comparative Examples 1-3. Shake the graduated cylinder up and down 10 times and 100 times at a frequency of 2 times / second and an amplitude of 30-35cm. Record the time (in seconds) for the foam to completely disappear. Set up a control blank sample without the high-efficiency defoaming block and calculate the defoaming efficiency.

[0061] Defoaming efficiency (%) = (Foam disappearance time of blank sample - Foam disappearance time of sample) / Foam disappearance time of blank sample × 100%.

[0062] 2. Foam suppression performance:

[0063] The foam suppression performance of the high-efficiency defoaming blocks prepared in Examples 1-3 and Comparative Examples 1-3 was tested using the bubbling method. 100 mL of standard foaming solution (as above) was added to a foam property tester (such as the lubricating oil foam tester specified in GB / T12579), the temperature was kept constant at 25°C, and an air flow of 100 mL / min was introduced for 30 minutes. The final foam volume (mL) was recorded, and the foam suppression rate was calculated.

[0064] Foam suppression rate (%) = (Foam volume of blank sample - Foam volume of sample) / Foam volume of blank sample × 100%.

[0065] 3. Sustained-release properties:

[0066] A bubble-blowing method was used. An aqueous solution containing 0.1% sodium dodecyl sulfate (SDS) was added to a 500 mL stoppered graduated cylinder. Stable foam was generated by introducing air through a glass frit funnel at a rate of 200 mL / min. High-efficiency defoaming blocks prepared in Examples 1-3 and Comparative Examples 1-3 were added, and the time required for the foam height to decrease from 500 mL to 100 mL (initial defoaming time, t0) was recorded. The defoaming blocks were removed, rinsed with deionized water, and then reintroduced into the foam solution. This test was repeated 10 times, and the defoaming time (t1-t0) was recorded each time. 10 Calculate the attenuation rate:

[0067] Attenuation rate (%) = (1-t) 10 / t0)×100%.

[0068] The performance test results are shown in Table 1.

[0069] Table 1. Performance test results of Examples 1-3 and Comparative Examples 1-3

[0070]

[0071] As shown in Table 1, the defoaming efficiency of the high-efficiency defoaming blocks prepared in Examples 1 to 3 of this application is 91.2% to 93.1%, and the foam suppression rate is 87.1% to 89.5%, which is higher than that of Comparative Examples 1 to 3 (68.3% to 82.4% and 57.2% to 72.6%, respectively). The defoaming performance decay rate of Examples 1 to 3 is 11.5% to 13.3%, which is significantly lower than that of Comparative Examples 1 to 3 (27.5% to 41.9%). This indicates that the high-efficiency defoaming blocks prepared in the examples of this application have excellent defoaming and foam suppression performance and have the advantage of long-term use.

[0072] In Comparative Example 1, without the addition of hydroxyl-terminated polybutadiene (HTPB), the terminal hydroxyl groups of HTPB undergo a condensation reaction with the siloxane bonds of the silicone polyether copolymer and copolymerize with free radicals generated from the decomposition of the thermally initiated crosslinking agent (BPO), forming a three-dimensional crosslinked network. Without HTPB, the silicone polyether copolymer only undergoes self-crosslinking initiated by BPO, resulting in a sparse network structure lacking flexible segments, which cannot effectively limit the diffusion of the defoamer. The defoamer is released rapidly in the initial stage, but because the network cannot prevent its dissolution, the concentration of the defoamer drops sharply after multiple uses, with the attenuation rate significantly increasing to 32.7%. The block structure formed by HTPB and the silicone polyether copolymer can regulate the release rate of the defoamer. Without HTPB, the release mode of the defoamer changes from "controlled slow release" to "burst release," resulting in a significant reduction in the foam suppression persistence, with a foam suppression rate of only 65.4%.

[0073] Comparative Example 2 did not involve vinyl grafting or silane modification of silica; silica was used directly. The vinyl and mercapto groups on the surface of activated silica can covalently crosslink with silicone polyether copolymers and HTPB. Unmodified silica, containing only hydroxyl groups, cannot chemically react with the system and disperses only through physical adsorption. This results in easy aggregation and insufficient crosslinking points, increased porosity of the crosslinked network, and uncontrolled diffusion rate of the defoamer. The initial defoaming efficiency was 68.3%, and the foam suppression rate was 57.2%, significantly lower than the example. The high specific surface area and active sites of activated silica can adsorb foaming substances. Unmodified silica has poor dispersibility and an inert surface, failing to effectively adsorb foaming agents. The lack of synergistic defoaming effect leads to decreased foam elimination efficiency and durability, with a decay rate of 41.9%.

[0074] Comparative Example 3 used traditional atmospheric pressure immersion instead of vacuum pressure impregnation. Vacuum pressure impregnation uses negative pressure difference and positive pressure (0.5MPa nitrogen) to promote the penetration of defoamer solution into the deep pores of polyurethane. Atmospheric pressure immersion relies only on capillary action, resulting in insufficient loading inside the pores and local enrichment on the surface. The composite functional material is unevenly distributed in the pores, and some areas lack synergistic materials, resulting in fluctuating defoaming efficiency of 82.4%. Uneven loading leads to local defoamer concentrations that are too high or too low, and inconsistent cross-linking reactions. After atmospheric pressure immersion, there may be areas inside the material that are not fully cross-linked, and the defoamer is easily lost from these weak points, with an attenuation rate of 27.5%, which is higher than that of the example.

[0075] The above results demonstrate and describe the basic principles and main features of this application, as well as its advantages.

[0076] Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the equivalents of the appended claims.

Claims

1. A high-efficiency defoaming block, characterized in that, The invention comprises a porous material carrier, a defoamer, and a composite functional material. The defoamer and the composite functional material are loaded onto the interior and surface of the porous material carrier by vacuum impregnation followed by gradient heating. The defoamer includes a silicone polyether copolymer, a thermally initiated crosslinking agent, an ultraviolet absorber, an antioxidant, and an anti-hydrolysis agent. The silicone polyether copolymer is obtained by reacting dimethyl polysiloxane, polyethylene glycol, and a catalyst. The composite functional material includes hydroxyl-terminated polybutadiene, activated silica, and ethyl acetate. The activated silica is obtained by modifying vinyl-grafted silica with silane.

2. The high-efficiency defoaming block according to claim 1, characterized in that, The defoamer is mixed with toluene at a mass ratio of (2-3):(7-8) to prepare a defoamer solution. The volume ratio of the defoamer solution, the composite functional material, and the porous material carrier is (0.4-0.45):0.4:

1. The mass ratio of the silicone polyether copolymer, the thermally initiated crosslinking agent, the ultraviolet absorber, the antioxidant, and the anti-hydrolysis agent is 100:(12.5-16.7):(8-12):(5-7):(1-1.5). The mass ratio of the dimethyl polysiloxane, polyethylene glycol, and the catalyst is 2:(2.9-3.1):0.

05. The mass ratio of the hydroxyl-terminated polybutadiene, the activated silica, and the ethyl acetate is (5-10):(9-11):

100.

3. The high-efficiency defoaming block according to claim 1, characterized in that, The porous material carrier is polyurethane foam sponge with a density of 18–75 kg / m³. 3 The pore size is 25-60 PPI; the catalyst is stannous octoate; the thermally initiated crosslinking agent is benzoyl peroxide; the ultraviolet absorber is UV-531; the anti-hydrolysis agent is carbodiimide; and the antioxidant is antioxidant 1010.

4. A method for preparing a high-efficiency defoaming block as described in any one of claims 1 to 3, characterized in that, Includes the following steps: S1. A silicone polyether copolymer is prepared in a nitrogen atmosphere using dimethyl polysiloxane, polyethylene glycol, and a catalyst; the silicone polyether copolymer, a thermally initiated crosslinking agent, a UV absorber, an antioxidant, and an anti-hydrolysis agent are mixed to obtain an antifoaming agent; the antifoaming agent is mixed with toluene to obtain an antifoaming agent solution; a silane hydrolysate is prepared using vinyltrimethoxysilane; silica is added to the silane hydrolysate, and the reaction yields vinyl-grafted silica; the vinyl-grafted silica is reacted with a first silane coupling agent to obtain activated silica; a composite functional material is obtained by mixing hydroxyl-terminated polybutadiene, the activated silica, and ethyl acetate. S2. Cut the polyurethane foam sponge into a set shape, place it in a vacuum pressure impregnation tank, evacuate the vacuum, add the defoamer solution and the composite functional material, and introduce nitrogen gas to obtain an impregnated defoaming block. Spray the residual defoamer solution and residual composite functional material in the vacuum pressure impregnation tank onto the surface of the impregnated defoaming block to obtain a defoaming block precursor. S3. The defoaming block precursor is subjected to gradient heating to obtain a cross-linked defoaming block. The cross-linked defoaming block is treated with a second silane coupling agent to obtain a silane-modified defoaming block. After treatment under set conditions, the high-efficiency defoaming block is obtained.

5. The method for preparing a high-efficiency defoaming block according to claim 4, characterized in that, The preparation of the silicone polyether copolymer described in S1 includes: mixing dimethyl polysiloxane, polyethylene glycol, and a catalyst in a nitrogen atmosphere, followed by a first-stage heating and a second-stage heating. The first-stage heating involves raising the reaction system to 70-75°C at a rate of 1.5°C / min and maintaining the temperature for 40-50 min. The second-stage heating involves raising the temperature of the system after the first-stage heating to 112-118°C at a rate of 1°C / min and maintaining the reaction for 5-6 h. The defoamer is mixed with toluene and stirred at 60-80°C to dissolve it, thus obtaining the defoamer solution.

6. The method for preparing a high-efficiency defoaming block according to claim 4, characterized in that, The silane hydrolysate described in S1 is obtained by adding glacial acetic acid and deionized water to an ethanol solution of vinyltrimethoxysilane and then hydrolyzing it at room temperature for 1.5–2.5 h. The concentration of the ethanol solution of vinyltrimethoxysilane is 4 wt%–6 wt%, and the volume ratio of the ethanol solution of vinyltrimethoxysilane, glacial acetic acid, and deionized water is 10:(0.1–0.2):(0.9–1.1). The reaction temperature for preparing the vinyl-grafted silica is 75–85 °C, and the reaction time is 5–7 h.

7. The method for preparing a high-efficiency defoaming block according to claim 4, characterized in that, The first silane coupling agent is γ-mercaptopropyltrimethoxysilane. The preparation of the activated silica includes mixing vinyl-grafted silica with γ-mercaptopropyltrimethoxysilane and toluene at a mass ratio of (9-11):1:50 and reacting at 45-55°C for 1.5-2.5 h. The composite functional material is obtained by sonication for 60-90 min.

8. The method for preparing a high-efficiency defoaming block according to claim 4, characterized in that, The vacuum pressure impregnation tank described in S2 is filled with nitrogen gas to 0.5 MPa and maintained for 20-30 minutes to obtain the impregnated defoaming block; the impregnated defoaming block is rotated at a speed of 110-130 r / min, and the residual defoamer solution and residual composite functional material are sprayed with a spray gun at a pressure of 0.3-0.4 MPa and a distance of 15-20 cm to obtain the precursor of the defoaming block.

9. The method for preparing a high-efficiency defoaming block according to claim 4, characterized in that, The gradient heating described in S3 includes a first gradient and a second gradient. The heating rate of the first gradient is 0.6℃ / min, heating to 50-60℃, and holding for 1.5-2.5h. The heating rate of the second gradient is 0.3℃ / min, heating to 75-80℃, and holding for 3-4h. The second silane coupling agent is KH-560. The preparation of the silane-modified defoaming block includes: immersing the crosslinked defoaming block in a 3%-4% KH-560 ethanol solution for 45-60min, and drying to obtain the silane-modified defoaming block. The treatment conditions for the silane-modified defoaming block are 70-80℃, relative humidity 63%-68%, and treatment time 60-72h.

10. The application of a high-efficiency defoaming block as described in any one of claims 1-3 in the preparation of defoaming products.

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