Efficient defoaming block as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of defoaming agents, and provides an efficient defoaming block as well as a preparation method and application thereof aiming at the problems that a traditional defoaming agent needs to be frequently added and the dosage is difficult to control. Polyurethane foam sponge is used as a carrier, a defoaming agent containing a silicon-containing polyether copolymer and a composite functional material of hydroxyl-terminated polybutadiene and activated silicon dioxide are loaded, and vacuum impregnation and gradient heating are performed to prepare the polyurethane foam material. The silicon polyether copolymer is subjected to rapid defoaming, hydroxyl-terminated polybutadiene and the silicon polyether copolymer are crosslinked to form a network to regulate and control slow release, activated silicon dioxide enhances the network through crosslinking and adsorbs foaming substances, a stabilizer is supplemented to improve the environmental durability, and all the components and the process cooperate to achieve 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 possible implementation, the defoaming agent is mixed with toluene at a mass ratio of (2-3):(7-8) to obtain a defoaming agent solution, and the volume ratio of the defoaming agent solution, the composite functional material, and the porous material carrier is (0.4-0.45):0.4:1; the mass ratio of the silicon polyether copolymer, the thermal initiation 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, the 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 possible implementation, the porous material carrier is a polyurethane foaming sponge with a density of 18-75 kg / m 3 , and a pore size of 25-60 PPI; the catalyst is stannous octoate; the thermal initiation 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 the polyurethane foaming sponge material provides a high specific surface area and abundant pore sizes, serving as a “storage-release” carrier for the defoaming agent.

[0009] In a second aspect, the application provides a method for preparing a high-efficiency defoaming block, including the following steps:

[0010] S1, preparing a silicon polyether copolymer from dimethyl polysiloxane, polyethylene glycol, and a catalyst in a nitrogen atmosphere; mixing the silicon polyether copolymer, a thermal initiation crosslinking agent, an ultraviolet absorber, an antioxidant, and an anti-hydrolysis agent to obtain a defoaming agent, and mixing the defoaming agent with toluene to obtain a defoaming agent solution; preparing a silane hydrolysis solution from vinyltrimethoxysilane, adding silica to the silane hydrolysis solution, and reacting to obtain vinyl-grafted silica; reacting a first silane coupling agent with the vinyl-grafted silica to obtain activated silica; and mixing hydroxyl-terminated polybutadiene, the activated silica, and ethyl acetate to obtain a composite functional material;

[0011] S2, cutting a polyurethane foaming sponge into a set shape, placing it in a vacuum pressure impregnation tank, vacuumizing, adding the defoaming agent solution and the composite functional material, and introducing nitrogen to obtain an impregnated defoaming block; and spraying the residual defoaming agent solution and the 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, gradient heating the defoaming block precursor to obtain a cross-linked defoaming block, treating the cross-linked defoaming block with a second silane coupling agent to obtain a silane-modified defoaming block, and treating the silane-modified defoaming block under a set condition to obtain the high-efficiency defoaming block body.

[0013] In one possible implementation, the preparation of the silicon polyether copolymer in S1 includes: mixing dimethylpolysiloxane, polyethylene glycol and a catalyst in a nitrogen atmosphere, and then performing first-stage heating and second-stage heating, the first-stage heating is to raise the reaction system to 70-75℃ at a rate of 1.5℃ / min and maintain for 40-50 min, and the second-stage heating is to raise the system after the first-stage heating to 112-118℃ at a rate of 1℃ / min and maintain for 5-6 h; and the defoaming agent is dissolved in toluene at 60-80℃ to obtain the defoaming agent solution.

[0014] The hydroxyl groups of dimethylpolysiloxane and polyethylene glycol (PEG) are condensed under the catalysis of stannous octoate to form Si-O-C bonds, thereby generating a silicon polyether block copolymer. The stannous octoate reduces the activation energy of the hydroxyl condensation through coordination effect, thereby promoting the dehydration condensation reaction. The silicon polyether copolymer has both the low surface tension (fast spreading and bubble breaking) of polysiloxane and the hydrophilicity (improved water phase compatibility) of polyether. The silicon-oxygen chain segment in the molecular structure of the silicon polyether copolymer can be quickly adsorbed on the surface of the foam liquid film to reduce the surface tension and break the liquid film, and the polyether chain segment can stabilize the dispersibility of the copolymer in the water phase through hydrogen bonding to avoid agglomeration and inactivation.

[0015] In one possible implementation, the silane hydrolysis solution in S1 is obtained by adding glacial acetic acid and deionized water to an ethyl alcohol solution of vinyltrimethoxysilane, and then hydrolyzing at room temperature for 1.5-2.5 h. The concentration of the ethyl alcohol solution of vinyltrimethoxysilane is 4wt%-6wt%, and the volume ratio of the ethyl alcohol solution of vinyltrimethoxysilane, glacial acetic acid and deionized water is 10:(0.1-0.2):(0.9-1.1). The preparation reaction temperature of the vinyl-grafted silicon dioxide is 75-85℃, and the reaction time is 5-7 h.

[0016] The vinyltrimethoxysilane (VTMO) is hydrolyzed to generate silanol under acidic conditions (adjusted by glacial acetic acid), and the silanol is condensed with the hydroxyl groups on the surface of the silicon dioxide to form Si-O-Si bonds. The mercapto groups (-SH) of the γ-mercaptopropyltrimethoxysilane (MPTMS) undergo radical addition reaction with the double bonds of the vinyl-grafted silicon dioxide to introduce mercapto active sites and graft the vinyl groups to the surface of the silicon dioxide.

[0017] In a possible implementation, the first silane coupling agent is γ-mercaptopropyl trimethoxysilane, and the preparation of the activated silica includes mixing the vinyl grafted silica with γ-mercaptopropyl trimethoxysilane and toluene at a mass ratio of (9-11):1:50, and reacting at 45-55 ℃ for 1.5-2.5 h; and the composite functional material is obtained after ultrasonic dispersion for 60-90 min.

[0018] The hydroxyl groups of the hydroxyl-terminated polybutadiene (HTPB) interact with the mercapto groups and silicon hydroxyl groups on the surface of the activated silica through hydrogen bonds and van der Waals forces to form a physical entanglement structure. Ultrasonic dispersion destroys the agglomerates through cavitation effect, promotes the uniform dispersion of the silica in the hydroxyl-terminated polybutadiene matrix, and forms an elastic network after the HTPB as a flexible segment is crosslinked with the silicon-polyether copolymer. The network pores allow the silicon-polyether copolymer to diffuse to the foam surface rapidly in the initial stage; at the same time, the network elasticity hinders the excessive loss of the copolymer, regulates the release rate of the defoaming agent, and realizes long-acting foam suppression. The vinyl groups and mercapto groups on the surface of the activated silica can undergo copolymerization with the silicon-polyether copolymer and the hydroxyl-terminated polybutadiene to form crosslinking points, thereby enhancing the network density of the material; at the same time, the high specific surface area of the silica can adsorb the surfactants in the foam liquid film to destroy the stability of the liquid film, thereby cooperating with the silicon-polyether copolymer to accelerate the defoaming.

[0019] In a possible implementation, the vacuum pressure impregnation tank in S2 is filled with nitrogen gas to 0.5 MPa for 20-30 min to obtain the impregnated defoaming block; the impregnated defoaming block is rotated at a rotating speed of 110-130 r / min, and the residual defoaming agent solution and the residual composite functional material are sprayed by 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] The vacuum removes the air in the pores of the polyurethane foaming sponge to form a negative pressure difference; and the pressurization (0.5 MPa nitrogen gas) promotes the defoaming agent solution and the composite functional material to penetrate into the deep pores through capillary action to complete the loading.

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

[0022] Benzoyl peroxide (BPO) decomposes at 75-80℃ to generate benzoyl oxygen free radicals, which initiate the radical copolymerization of the vinyl groups of the silicon polyether copolymer, the double bonds of HTPB and the mercapto groups of the activated silica, forming a three-dimensional crosslinked network, preventing the loss of the defoaming agent in use, and improving the mechanical strength of the material; the network pore size limits the diffusion rate of the silicon polyether copolymer, maintaining long-acting defoaming.

[0023] After hydrolysis, KH-560 (γ-glycidyl ether propyl trimethoxysilane) condenses with the hydroxyl groups on the surface of the crosslinked network to form a dense protective film, and at 70-80℃, the incompletely crosslinked groups further react, releasing the internal thermal stress of the material, improving the crosslinking degree, and the protective film isolates water, oxygen and ultraviolet light, the UV-531 ultraviolet absorber and the antioxidant 1010 capture free radicals, the anti-hydrolysis agent carbodiimide neutralizes trace amounts of carboxylic acid to inhibit the degradation of the material; thermal aging homogenizes the crosslinked network, reducing the decay rate of the defoaming efficiency.

[0024] In a third aspect, the application provides a high-efficiency defoaming block for use in the field of defoaming.

[0025] Beneficial technical effects:

[0026] The present application discloses a high-efficiency defoaming block, its preparation method and application, which uses polyurethane foaming sponge as a porous material carrier, and loads a defoaming agent containing a silicon polyether copolymer and a composite functional material composed of hydroxyl-terminated polybutadiene and activated silica. The silicon polyether copolymer rapidly spreads on the liquid film surface when it contacts the foam, and promotes the rupture of the liquid film by reducing the surface tension, achieving rapid defoaming. The hydroxyl-terminated polybutadiene and the silicon polyether copolymer form a block copolymer through condensation reaction of the hydroxyl groups and the silicon-oxygen bond, and the unsaturated double bonds of the block copolymer undergo copolymerization and addition reaction with the vinyl-containing silica under the action of a thermal initiator, building a crosslinked network. The network not only enhances the adhesion stability of the defoaming agent in the pores of the polyurethane foaming sponge, but also controls the molecular diffusion rate through physical barrier to achieve slow release of the defoaming agent, prolonging the defoaming time. The vinyl-containing silica enhances the network density by forming covalent bonds with the silicon polyether copolymer through the surface vinyl groups, and also adsorbs the foaming substances by utilizing the high specific surface area of the nanoparticles to destroy the stability of the foam. The high-efficiency defoaming block prepared by the present application has both high-efficiency defoaming ability and long-acting slow-release performance. BRIEF DESCRIPTION OF DRAWINGS

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

[0028] Figure 2 The figure is a physical picture of the high-efficiency defoaming block prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0029] In order to make the technical problems, technical solutions and beneficial effects to be solved in the present application clearer, the present application will be further described in detail below in conjunction with embodiments. However, this should not be understood as a limitation on the scope of the present application to the following examples. Without departing from the above method idea of the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor shall fall within the scope of protection of the present application.

[0030] In the present application, the terms used in the present application are merely for the purpose of describing specific embodiments, and are not intended to limit the present application.

[0031] In the present application, the singular forms "is", "or", "a", "any" and "the" are intended to include the plural forms, unless the context clearly indicates otherwise.

[0032] In addition, if the terms "first", "second" appear, they are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0033] The following will specifically describe a high-efficiency defoaming block, a preparation method and application thereof provided by the present application in conjunction with different embodiments.

[0034] Embodiment 1

[0035] As shown in Figure 1 , a preparation method of a high-efficiency defoaming block comprises the following steps:

[0036] 1. Under nitrogen protection, dimethyl polysiloxane, polyethylene glycol and stannous octoate are mixed in a mass ratio of 2:3:0.05, raised to 72℃ at a rate of 1.5℃ / min, maintained for 45min, then raised to 115℃ at a rate of 1℃ / min, maintained for 5.5h of reaction, distilled under reduced pressure to obtain a silicon polyether copolymer; the silicon polyether copolymer, thermal initiation crosslinking agent benzoyl peroxide, ultraviolet absorber UV-531, antioxidant 1010 and anti-hydrolysis agent carbodiimide are mixed in a mass ratio of 100:14.6:10:6:1.2 to obtain a defoaming agent, the defoaming agent is mixed with toluene in a mass ratio of 2.5:7.5, stirred at 70℃ until completely dissolved to obtain a defoaming agent solution;

[0037] 2. A silane hydrolysis solution was prepared by adding glacial acetic acid dropwise to a 5 wt% solution of vinyltrimethoxysilane in ethanol, and then adding deionized water, with a volume ratio of 10:0.15:1, and hydrolyzing at room temperature for 2 hours; then silica was added to the silane hydrolysis solution, and refluxed at 80°C for 6 hours, centrifuged, and the solid was washed with ethanol and dried to obtain vinyl-grafted silica; the vinyl-grafted silica was mixed with γ-mercaptopropyltrimethoxysilane and toluene at a mass ratio of 10:1:50, and reacted at 50°C for 2 hours, centrifuged, washed with toluene, and dried to obtain activated silica; the activated silica was mixed with hydroxyl-terminated polybutadiene and ethyl acetate at a mass ratio of 8:10:100, and ultrasonically dispersed for 75 minutes to form a composite functional material;

[0038] 3. A polyurethane foam sponge with a density of 40 kg / m 3 and a pore size of 45 PPI was cut into blocks of 5 cm x 18 cm x 1 cm, placed in a vacuum pressure impregnation tank, vacuumed to 0.098 MPa for 25 minutes, injected with a defoaming agent solution and a composite functional material, with a volume ratio of 0.42:0.4:1, filled with nitrogen to 0.5 MPa for 25 minutes to obtain an impregnated defoaming block, and the impregnated defoaming block was removed and placed in a rotary spraying device, rotated at a speed of 120 r / min, and the residual defoaming agent solution and residual composite functional material in the vacuum pressure impregnation tank were sprayed onto the surface of the impregnated defoaming block using a high-pressure spray gun at a pressure of 0.35 MPa and a distance of 18 cm to obtain a defoaming block precursor;

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

[0040] Example 2

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

[0042] 1. Under the protection of nitrogen, dimethyl polysiloxane, polyethylene glycol and stannous octoate were mixed in a mass ratio of 2:2.9:0.05, heated at a rate of 1.5 ℃ / min to 70 ℃ and maintained for 50 min, then heated at a rate of 1 ℃ / min to 112 ℃ and maintained for 6 h, distilled under reduced pressure to obtain a silicone polyether copolymer; the silicone polyether copolymer, thermal initiation 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 a defoaming agent, the defoaming agent was mixed with toluene in a mass ratio of 2:8, stirred at 70 ℃ until completely dissolved to obtain a defoaming agent solution;

[0043] 2. A silane hydrolysis solution was prepared by adding glacial acetic acid dropwise to a 4 wt% vinyltrimethoxysilane ethanol solution, and then adding deionized water, with a volume ratio of the vinyltrimethoxysilane ethanol solution, glacial acetic acid and deionized water being 10:0.1:1.1, and hydrolyzing at room temperature for 1.5 h; silica was added to the silane hydrolysis solution, refluxed at 75 ℃ for 7 h, centrifuged, and the solid was washed with ethanol and dried to obtain vinyl-grafted silica; the vinyl-grafted silica was mixed with γ-mercaptopropyltrimethoxysilane and toluene in a mass ratio of 9:1:50, reacted at 45 ℃ for 2.5 h, centrifuged, washed with toluene and dried to obtain activated silica; a composite functional material was prepared by mixing hydroxyl-terminated polybutadiene, activated silica and ethyl acetate in a mass ratio of 5:11:100 and ultrasonic dispersing for 60 min;

[0044] 3. A polyurethane foam sponge with a density of 18 kg / m 3 and a pore size of 60 PPI was cut into blocks with a size of 5 cm×18 cm×1 cm, placed in a vacuum pressure impregnation tank, vacuumed to 0.098 MPa and maintained for 25 min, injected with the defoaming agent solution and the composite functional material, with a volume ratio of the defoaming agent solution, the composite functional material and the porous material carrier being 0.4:0.4:1, filled with nitrogen to 0.5 MPa and maintained for 20 min to obtain an impregnated defoaming block, the impregnated defoaming block was taken out and placed in a rotary spraying device, rotated at a speed of 110 r / min, and the residual defoaming agent solution and the residual composite functional material in the vacuum pressure impregnation tank were sprayed onto the surface of the impregnated defoaming block by a high-pressure spray gun at a pressure of 0.3 MPa and a distance of 15 cm to obtain a defoaming block precursor;

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

[0046] Example 3

[0047] As Figure 1 shown, a preparation method of a high-efficiency defoaming block comprises the following steps:

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

[0049] 2. A 6wt% ethyl alcohol solution of vinyl trimethoxysilane is added dropwise with glacial acetic acid, then deionized water is added, the volume ratio of the ethyl alcohol solution of vinyl trimethoxysilane, glacial acetic acid and deionized water is 10:0.2:0.9, hydrolysis is carried out at room temperature for 2.5 h to obtain a silane hydrolysis solution; silica is added to the silane hydrolysis solution, refluxed at 85℃ for 5 h, centrifuged, the solid is washed with ethanol and dried to obtain vinyl grafted silica; the vinyl grafted silica is mixed with γ-mercaptopropyl trimethoxysilane and toluene in a mass ratio of 11:1:50, reacted at 55℃ for 1.5 h, centrifuged, washed with toluene and dried to obtain activated silica; the mass ratio of hydroxyl-terminated polybutadiene, activated silica and ethyl acetate is 10:9:100, ultrasonic dispersion is carried out for 90 min to form a composite functional material;

[0050] 3. A polyurethane foaming sponge with a density of 75kg / m 3 and a pore size of 25PPI is cut into a block shape of 5cm×18cm×1cm, placed in a vacuum pressure impregnation tank, vacuumed to 0.098MPa for 25 min, injected with the defoaming agent solution and the composite functional material, the volume ratio of the defoaming agent solution, the composite functional material and the porous material carrier is 0.45:0.4:1, nitrogen is filled to 0.5MPa for 30 min to obtain an impregnated defoaming block, the impregnated defoaming block is taken out and placed in a rotary spraying device, rotated at a speed of 130r / min, the residual defoaming agent solution and the residual composite functional material in the vacuum pressure impregnation tank are sprayed onto the surface of the impregnated defoaming block by a high-pressure spray gun at a pressure of 0.4MPa and a distance of 20cm to obtain a defoaming block precursor;

[0051] 4. The defoaming block precursor was warmed to 60℃ at 0.6℃ / min, and kept for 1.5h, then warmed to 80℃ at 0.3℃ / min, and kept for 3h to obtain a crosslinked defoaming block; the crosslinked defoaming block was immersed in an ethanol solution of 4% silane coupling agent KH-560 for 45min, and then dried at room temperature for 3h at 45℃ 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 body.

[0052] Comparative Example 1

[0053] A method for preparing a high-efficiency defoaming block body, the implementation steps and parameters being the same as those of Example 1, except that no hydroxyl-terminated polybutadiene was added.

[0054] Comparative Example 2

[0055] A method for preparing a high-efficiency defoaming block body, the implementation steps and parameters being the same as those of Example 1, except that no vinyl grafting and silane modification treatment was performed on the silica, and activated silica was replaced by silica.

[0056] Comparative Example 3

[0057] A method for preparing a high-efficiency defoaming block body, the implementation steps and parameters being the same as those of Example 1, except that a traditional atmospheric immersion method was used instead of vacuum pressure impregnation.

[0058] Performance test:

[0059] 1. Defoaming performance:

[0060] A standard foaming solution was prepared by dissolving 5g of nonylphenol polyoxyethylene ether (NP-10) and 5g of sodium dodecyl benzene sulfonate (SDBS) in 990mL of deionized water, stirring until uniform and transparent, and then taking 500mL of the standard foaming solution in a graduated cylinder with a stopper, and warming to 25℃. 0.2g of the high-efficiency defoaming block prepared in Examples 1-3 and Comparative Examples 1-3 was added, and the graduated cylinder was shaken up and down 10 times and 100 times at a frequency of 2 times / sec and an amplitude of 30-35cm. The time (seconds) for the foam to completely disappear was recorded. A blank sample without the addition of the high-efficiency defoaming block was set, and the defoaming efficiency was calculated.

[0061] Defoaming efficiency (%) = (blank sample foam disappearance time - sample foam disappearance time) / blank sample foam disappearance time x 100%.

[0062] 2. Foam suppression performance:

[0063] The foam suppression performance of the high-efficiency defoaming blocks prepared in Examples 1 to 3 and Comparative Examples 1 to 3 was tested using the bubbling method. 100 mL of the standard foaming solution (as described above) was added to a foam property tester (e.g., a lubricating oil foam tester as specified in GB / T 12579). The temperature was maintained at 25°C, and air flow was introduced at 100 mL / min for 30 minutes. The final foam volume (mL) was recorded, and the foam suppression rate was calculated as follows:

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

[0065] 3. Sustained release performance:

[0066] Using the bubbling method, add an aqueous solution containing 0.1% sodium dodecyl sulfate (SDS) to a 500mL stoppered measuring cylinder, and introduce air at a rate of 200mL / min through a glass frit funnel to generate stable foam. Add the high-efficiency defoaming blocks prepared in Examples 1 to 3 and Comparative Examples 1 to 3, and record the time required for the foam height to drop from 500mL to 100mL (initial defoaming time, t0). Remove the defoaming block, rinse with deionized water, and re-add the foam solution. Repeat the test 10 times, and record the defoaming time (t1-t 10 ). Calculate the decay rate:

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

[0068] The above 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 can be seen from Table 1, the defoaming efficiency of the high-efficiency defoaming blocks prepared in Examples 1 to 3 of the present application is 91.2% to 93.1%, and the foam suppression rate is 87.1% to 89.5%, which are higher than 68.3% to 82.4% and 57.2% to 72.6% of Comparative Examples 1 to 3, and the defoaming performance attenuation rate of Examples 1 to 3 is 11.5% to 13.3%, which is significantly lower than 27.5% to 41.9% of Comparative Examples 1 to 3, indicating that the high-efficiency defoaming blocks prepared in the examples of the present application have excellent defoaming and foam suppression properties and have the advantage of long-term use.

[0072] Comparative Example 1 omitted the addition of hydroxyl-terminated polybutadiene (HTPB). The terminal hydroxyl groups of HTPB condensed with the siloxy bonds of the silicone polyether copolymer and copolymerized with free radicals generated by the decomposition of the thermally initiated crosslinker (BPO), forming a three-dimensional crosslinked network. Without HTPB, the silicone polyether copolymer only crosslinked itself through BPO, resulting in a sparse network structure and a lack of flexible segments, which failed to effectively restrict the diffusion of the defoamer. The defoamer was initially released rapidly, but because the network failed to prevent its dissolution, the defoamer concentration dropped sharply after repeated use, with the decay rate significantly increasing to 32.7%. The block structure formed by HTPB and the silicone polyether copolymer regulates the defoamer release rate. In the absence of HTPB, the defoamer release pattern shifted from a controlled, sustained release to a burst release, significantly reducing the duration of antifoaming, resulting in a suppression rate of only 65.4%.

[0073] Comparative Example 2 does not carry out vinyl grafting and silane modification on silica, and silica is used directly. The vinyl and thiol groups on the surface of the activated silica can be covalently cross-linked with the silicon polyether copolymer and HTPB. The surface of the unmodified silica contains only hydroxyl groups and cannot react chemically with the system. It is dispersed only by physical adsorption, easily agglomerated and insufficient cross-linking points, the cross-linked network porosity increases, the defoamer diffusion rate is out of control, the initial defoaming efficiency is 68.3%, and the foam suppression rate is 57.2%, which is significantly lower than that of the embodiment. The high specific surface area and surface active sites of the activated silica can adsorb foaming substances. The unmodified silica has poor dispersibility and surface inertness, and cannot effectively adsorb the foaming agent. The synergistic defoaming effect is missing, resulting in a decrease in foam elimination efficiency and durability, with a decay rate of 41.9%.

[0074] Comparative Example 3 uses traditional normal pressure immersion instead of vacuum pressure impregnation. Vacuum pressure impregnation promotes the penetration of the defoamer solution into the deep pores of the polyurethane through negative pressure difference and positive pressure (0.5 MPa nitrogen). Normal 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, some areas lack synergistic materials, and the defoaming efficiency fluctuates, with a defoaming efficiency of 82.4%; the uneven loading leads to excessively high or low local defoamer concentrations and inconsistent cross-linking reactions. After normal 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 embodiment.

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

[0076] Those skilled in the art should understand that the present application is not limited to the above-described embodiments. The above-described embodiments and descriptions are merely illustrative of the principles of the present application. Various changes and improvements may be made to the present application without departing from the spirit and scope of the present application. Such changes and improvements are intended to fall within the scope of the present application. The scope of protection claimed in the present 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 inside and on the surface of the porous material carrier by vacuum impregnation followed by gradient heating. The defoamer comprises a silicone polyether copolymer, a heat-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 comprises terminal hydroxyl polybutadiene, activated silica and ethyl acetate. The activated silica is vinyl-grafted silica modified by silane.

2. A high-efficiency defoaming block according to claim 1, characterized in that: The defoamer and toluene are mixed in a mass ratio of (2-3):(7-8) to prepare a defoamer solution, and 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, the polyethylene glycol and the catalyst is 2:(2.9-3.1):0.05; and the mass ratio of the terminal hydroxyl 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 a polyurethane foam sponge with a density of 18 to 75 kg / m 3 , a pore size of 25-60PPI; the catalyst is stannous octoate, the thermally initiated cross-linking 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 according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. In a nitrogen atmosphere, a silicon polyether copolymer is prepared using dimethyl polysiloxane, polyethylene glycol, and a catalyst; the silicon polyether copolymer, a thermally initiated crosslinking agent, an ultraviolet absorber, an antioxidant, and an anti-hydrolysis agent are mixed to obtain a defoamer, and the defoamer is mixed with toluene to obtain a defoamer solution; a silane hydrolyzate is prepared using vinyltrimethoxysilane, silicon dioxide is added to the silane hydrolyzate to react to obtain vinyl-grafted silicon dioxide; a first silane coupling agent is reacted with the vinyl-grafted silicon dioxide to obtain activated silicon dioxide; and terminal hydroxyl polybutadiene, the activated silicon dioxide, and ethyl acetate are mixed to obtain a composite functional material; S2. Cutting the polyurethane foam sponge into a set shape, placing it in a vacuum pressure impregnation tank, evacuating it, adding the defoamer solution and the composite functional material, passing nitrogen gas, obtaining an impregnated defoaming block, spraying the residual defoamer solution and the residual composite functional material in the vacuum pressure impregnation tank onto the surface of the impregnated defoaming block, and obtaining a defoaming block precursor; S3, gradient heating the defoaming block precursor to obtain a cross-linked defoaming block, treating the cross-linked defoaming block with a second silane coupling agent to obtain a silane-modified defoaming block, and obtaining the high-efficiency defoaming block after treatment under set conditions.

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, and then performing a first stage heating and a second stage heating, wherein the first stage heating is to raise the temperature of the reaction system to 70-75°C at a rate of 1.5°C / min and maintain it for 40-50 minutes, and the second stage heating is to raise the temperature of the system after the first stage heating to 112-118°C at a rate of 1°C / min and maintain the reaction for 5-6 hours; the defoaming agent is mixed with toluene and dissolved with stirring at 60-80°C to obtain the defoaming agent solution.

6. The method for preparing a high-efficiency defoaming block according to claim 4, characterized in that: The silane hydrolyzate in S1 is obtained by adding glacial acetic acid and deionized water to an ethanol solution of vinyltrimethoxysilane, and hydrolyzing at room temperature for 1.5 to 2.5 hours. The concentration of the ethanol solution of vinyltrimethoxysilane is 4wt%-6wt%, 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 the preparation of the vinyl grafted silica is 75-85°C, and the reaction time is 5 to 7 hours.

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, and the preparation of the activated silica includes mixing vinyl-grafted silica, γ-mercaptopropyltrimethoxysilane and toluene in a mass ratio of (9-11):1:50, and reacting at 45-55°C for 1.5 to 2.5 hours; the composite functional material is obtained after ultrasonic treatment for 60 to 90 minutes.

8. The method for preparing a high-efficiency defoaming block according to claim 4, characterized in that: The vacuum pressure impregnation tank in S2 is filled with nitrogen to 0.5 MPa and maintained for 20 to 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 defoaming agent solution and the residual composite functional material are sprayed with a spray gun at a pressure of 0.3-0.4 MPa and a distance of 15 to 20 cm to obtain the defoaming block precursor.

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

10. Use of the high-efficiency defoaming block according to any one of claims 1 to 3 in the preparation of defoaming products.

Images