Defoaming agent containing nano MOF (Metal Organic Framework) as well as preparation method and application of defoaming agent

Abstract

The invention discloses a defoaming agent containing nano MOF and a preparation method and application thereof, and the defoaming agent is prepared from the following components in parts by weight: 1-5 parts of nano MOF, 10-20 parts of hyperbranched polyethyl siloxane, 10-30 parts of fluoropolyether, 1-5 parts of modified hydrophobic white carbon black, 1-5 parts of a base catalyst, 2-10 parts of an emulsifier and 1-3 parts of a stabilizer. The nano MOF in the defoaming agent is compounded with defoaming agents such as hyperbranched polyethyl siloxane and fluoropolyether, so that the high temperature resistance and chemical stability of the defoaming agent are improved. The nano MOF and the nano modified hydrophobic white carbon black are hybridized, and the hydrophobic nano MOF and the modified hydrophobic white carbon black are embedded into a hyperbranched skeleton, so that the mechanical puncture capacity of the particles is improved. The nano MOF can gradually release defoaming active components in the system, the defoaming duration is prolonged, and the foam inhibition performance of the defoaming agent in 3D printing is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of defoamers, and in particular to a defoamer containing nano-MOF, and a preparation method and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance some understanding of the overall background of the invention and should not be necessarily regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] Defoamers are chemical additives used to eliminate or suppress bubbles in liquids. During the 3D printing process, especially when using materials like thermoplastics, bubbles are generated during the mixing, extrusion, or curing process. These bubbles can cause surface defects, internal porosity, or reduced structural strength in printed parts. These bubbles can lead to material waste or print failures. The use of defoamers can reduce scrap rates and improve material utilization.

[0004] Under high-temperature conditions, some defoamers decompose, volatilize, or undergo structural damage, significantly reducing their defoaming performance. For example, traditional silicone defoamers are susceptible to silane-oxygen bond breakage at high temperatures, while polyether defoamers can become ineffective due to molecular chain degradation. This lack of thermal stability directly limits their ability to sustain defoaming during 3D printing.

[0005] High temperatures accelerate the defoamer's consumption rate, significantly shortening the duration of foam suppression. For example, during continuous high-temperature reactions, the defoamer can quickly lose effectiveness due to evaporation, migration, or adsorption into the system, necessitating frequent replenishment to maintain its effectiveness. This lack of durability increases production costs and operational complexity, making it particularly unsuitable for 3D printing industrial processes.

[0006] Defoamers can effectively reduce bubbles inside and on the surface of printed parts, preventing the formation of voids, cracks, or increased surface roughness caused by these bubbles. During printing, bubbles can lead to poor interlayer bonding. Defoamers can destabilize the bubble film and inhibit foam formation, improving interlayer bonding and enhancing the mechanical strength of printed parts. They can also enhance the quality and performance of printed parts, making the surface smoother and the internal structure denser, thereby increasing the mechanical strength and stability of the printed part. Summary of the Invention

[0007] In view of the deficiencies of the prior art, the present invention provides a defoaming agent containing nano-MOF and a preparation method and application thereof.

[0008] The technical solution adopted in the present invention is as follows:

[0009] In the first aspect of the present invention, a defoamer containing nano-MOF is provided, which is composed of the following components, by weight: 1 to 5 parts of nano-MOF, 10 to 20 parts of hyperbranched polyethylsiloxane, 10 to 30 parts of fluoropolyether, 1 to 5 parts of modified hydrophobic silica, 1 to 5 parts of alkaline catalyst, 2 to 10 parts of emulsifier, and 1 to 3 parts of stabilizer.

[0010] In one or some embodiments of the present invention, the nano-MOF is one or more of UiO-66-CH3, UiO-66-CF3, and UiO-66-F4. The MOF's inherent nanostructure destabilizes the foam film. MOF's high thermal stability protects the polyether molecules from decomposition at high temperatures. Methyl and fluorinated modifications significantly enhance the defoamer's hydrophobicity and chemical stability.

[0011] In one or some embodiments of the present invention, the molecular weight of the hyperbranched polyethylsiloxane is 1000-50000 g / mol, the degree of branching is 40-70%, the synergistic effect of the nano-MOF and the hyperbranched siloxane enhances the foam breaking efficiency, the pore structure of the MOF can adsorb the surfactant in the foam liquid film, and the hyperbranched polyethylsiloxane has a large number of terminal functional groups, which enhances the ability to penetrate the foam liquid film and can enhance the contact efficiency with the foam liquid film.

[0012] In one or some embodiments of the present invention, the fluoropolyether comprises a polyether (ethylene oxide / propylene oxide copolymer, PEO / PPO) backbone with fluoroalkyl side chains (e.g., -CF3, -CF2H) or fluorinated end groups (e.g., -OCF3), a molecular weight of 5000–100,000 g / mol, and a fluorination degree of 30–70%. The presence of fluorine atoms in the backbone or side chains of the fluoropolyether imparts extremely low surface tension, enabling rapid spreading across the surface of the liquid film and disrupting foam. The synergistic effect of the nano-MOF and the fluoropolyether modulates the hydrophilic-hydrophobic balance. The pore size and surface chemistry of the MOF can be used to adjust the HLB value of the fluoropolyether, making it more adaptable to different systems.

[0013] In one or some embodiments of the present invention, the modified hydrophobic silica is one or more of methyl-modified hydrophobic silica, octadecyl-modified hydrophobic silica, siloxane-modified hydrophobic silica, and fluoroalkyl-modified hydrophobic silica.

[0014] In one or some embodiments of the present invention, the base catalyst is one or a mixture of any of sodium hydroxide, potassium hydroxide, potassium carbonate, aqueous ammonia, sodium ethoxide, or the like.

[0015] In one or some embodiments of the present invention, the emulsifier is one or more of polyglycerol polyricinoleate, sucrose polyricinoleate, acetylated monoglyceride, lignin sulfonate grafted polyether, and hyperbranched polyglycerol ester.

[0016] In one or some embodiments of the present invention, the stabilizer is one or more of organic bentonite, polyamide wax, polyethylene glycol, acrylate copolymer, and nanoclay.

[0017] In a second aspect of the present invention, a method for preparing the defoaming agent containing nano-MOF is provided, the method comprising the following steps:

[0018] (1) placing hyperbranched polyethylsiloxane, nano-MOF, modified hydrophobic silica, and an alkaline catalyst in a reaction kettle, controlling the temperature in the reaction kettle to 80-180° C. and stirring uniformly to prepare a first mixed solution;

[0019] (2) adding a fluoropolyether and an emulsifier to the first mixed solution and stirring uniformly to obtain a second mixed solution;

[0020] (3) Add a stabilizer to the second mixed solution and stir evenly to prepare a defoaming agent.

[0021] In a third aspect of the present invention, use of the defoaming agent in 3D printing is provided.

[0022] In one or some embodiments of the present invention, the defoaming agent is used in 3D printing thermoplastics.

[0023] Compared with the related art known to the inventors, one of the technical solutions of the present invention has the following beneficial effects:

[0024] The defoamer of the present invention combines nano-MOFs with defoamers such as hyperbranched polyethylsiloxane and fluoropolyether to enhance the defoamer's high-temperature resistance and chemical stability. The nano-MOFs are hybridized with nano-modified hydrophobic silica, embedding the hydrophobic nano-MOFs and modified hydrophobic silica within the hyperbranched framework to enhance the particles' mechanical puncture resistance. The nano-MOFs gradually release their active defoaming ingredients within the system, extending the duration of defoaming and improving the defoamer's anti-foaming properties in 3D printing.

[0025] The pore structure of nano-MOF can adsorb hyperbranched siloxane and surfactants in the foam liquid film, enhancing the foam breaking efficiency. Hyperbranched polyethylsiloxane has a large number of terminal functional groups, which enhances the ability to penetrate the foam liquid film and enhances the contact efficiency with the foam liquid film.

[0026] The defoamer of the present invention is applied to the field of 3D printing, and has excellent performance in materials such as thermoplastics. The defoamer has good compatibility with thermoplastic filaments and will not produce adverse reactions or affect the performance of printed parts during the printing process. DETAILED DESCRIPTION

[0027] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0028] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations and / or combinations thereof.

[0029] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0030] Example 1

[0031] A defoamer containing nano-MOF, composed of the following components by weight: 2 parts of nano-MOF, 15 parts of hyperbranched polysiloxane, 20 parts of fluoropolyether, 2 parts of modified hydrophobic silica, 2 parts of alkaline catalyst, 5 parts of emulsifier, and 2 parts of stabilizer;

[0032] Wherein, the nano-MOF is UiO-66-CH3;

[0033] The hyperbranched polysiloxane is a hyperbranched polyethylsiloxane (branching degree of 0.3, molecular weight of 10000 g / mol, branching point substitution);

[0034] The fluoropolyether is a polyether (ethylene oxide PEO / propylene oxide PPO copolymer) with a main chain and a fluorinated alkyl group -CF2H on the side chain, and has a molecular weight of 8000 g / mol;

[0035] The modified hydrophobic silica is methyl modified hydrophobic silica;

[0036] The alkaline catalyst is sodium hydroxide;

[0037] The emulsifier is polyglycerol polyricinoleate, the degree of polymerization of polyglycerol is 4, and the degree of polymerization of polyricinoleic acid chain is 3;

[0038] The stabilizer is organic bentonite.

[0039] The preparation method of the defoamer containing nano-MOF comprises the following steps:

[0040] (1) placing hyperbranched polysiloxane, MOF, modified hydrophobic silica, and an alkaline catalyst in a reactor, controlling the temperature in the reactor to 150° C. and stirring for 3 hours to prepare a first mixed solution;

[0041] (2) Adding fluoropolyether and emulsifier to the first mixed solution and stirring for 1 hour to prepare a second mixed solution.

[0042] (3) Add a stabilizer to the second mixed solution and stir for 1 hour to prepare a defoaming agent.

[0043] Example 2

[0044] A defoamer containing nano-MOF, composed of the following components by weight: 1 part of nano-MOF, 10 parts of hyperbranched polysiloxane, 10 parts of fluoropolyether, 1 part of modified hydrophobic silica, 1 part of alkaline catalyst, 2 parts of emulsifier, and 1 part of stabilizer;

[0045] Wherein, the nano-MOF is UiO-66-CF3;

[0046] The hyperbranched polysiloxane is a hyperbranched polyethylsiloxane (branching degree of 0.4, molecular weight of 20000 g / mol, linear segment);

[0047] The fluoropolyether is a polyether (ethylene oxide PEO / propylene oxide PPO copolymer) with a main chain and a fluorinated alkyl group -CF3 on the side chain and a molecular weight of 15000 g / mol;

[0048] The modified hydrophobic silica is octadecyl modified hydrophobic silica;

[0049] The base catalyst is potassium hydroxide;

[0050] The emulsifier is sucrose polyricinoleate, the average number of hydroxyl groups replaced by polyricinoleate (PRA) in the sucrose molecule is DS=5, and the degree of polymerization of the polyricinoleate chain is 3;

[0051] The stabilizer is nanoclay.

[0052] The preparation method is the same as Example 1.

[0053] Example 3

[0054] A defoamer containing nano-MOF, composed of the following components by weight: 5 parts of nano-MOF, 20 parts of hyperbranched polysiloxane, 10 parts of fluoropolyether, 5 parts of modified hydrophobic silica, 5 parts of alkaline catalyst, 10 parts of emulsifier, and 3 parts of stabilizer;

[0055] Wherein, the nano-MOF is UiO-66-F4;

[0056] The hyperbranched polysiloxane is a hyperbranched polyethylsiloxane (with a degree of branching of 0.5, a molecular weight of 50,000 g / mol, and branch point substitution);

[0057] The fluoropolyether is a polyether (ethylene oxide PEO / propylene oxide PPO copolymer) with a main chain, a fluorinated end group (-OCF3), and a molecular weight of 30,000 g / mol;

[0058] The modified hydrophobic silica is siloxane-modified hydrophobic silica;

[0059] The alkaline catalyst is aqueous ammonia;

[0060] The emulsifier is a hyperbranched polyglycerol ester with a polymerization degree of 40 glycerol units (corresponding to a molecular weight of 4000 g / mol) and a branching degree of 0.5;

[0061] The stabilizer is polyethylene glycol with a molecular weight of 1000 g / mol.

[0062] The preparation method is the same as Example 1.

[0063] Comparative Example 1

[0064] The UiO-66-CH3 in Example 1 was replaced with UiO-66. Other conditions, parameters and preparation methods were the same as in Example 1, but the experimental results were not good.

[0065] Comparative Example 2

[0066] The difference from Example 1 is that the nano-MOF is replaced by 4A molecular sieve, which has a specific surface area of ​​600m 2 / g, and other conditions, parameters and preparation method are the same as those in Example 1.

[0067] Comparative Example 3

[0068] The difference from Example 1 is that the hyperbranched polyethylsiloxane is replaced with an organosiloxane comprising dimethyl silicone oil and hydroxy silicone oil, specifically comprising: dimethyl silicone oil with a viscosity of 350-500 cSt, dimethyl silicone oil with a viscosity of 5000-6000 cSt, and hydroxy silicone oil with a viscosity of 10000 cSt, in a weight ratio of 9:5:6. Other conditions, parameters, and preparation methods are the same as those in Example 1.

[0069] Comparative Example 4

[0070] The difference from Example 1 is that the weight portion of nano-MOF is 0.5 parts, the weight portion of hyperbranched polysiloxane is 8 parts, and the weight portion of fluoropolyether is 25 parts.

[0071] Experimental example

[0072] Test Method

[0073] High temperature resistance: The wires to which the defoaming agents of the examples and comparative examples were applied were heated in an oven at 200°C for 2 hours, and the formation of bubbles on the surface was observed and the mass loss rate was measured.

[0074] Defoaming time: The molten plastics (230° C.) containing the defoaming agents of the examples and comparative examples were injected into the mold, and the time from injection to complete disappearance of the bubbles was recorded (recorded by a high-speed camera).

[0075] Foam suppression performance: Dynamic test: The test samples containing the defoaming agents of the embodiment and the comparative example were heated continuously in an extruder for 1 hour, and samples were taken every 10 minutes to observe the bubble density.

[0076] 3D printing results: Print standard test models (such as 20mm cubes) to evaluate surface finish (roughness tester), interlayer bonding strength (tensile test) and porosity (micro CT scan).

[0077] The results are as follows:

[0078]

[0079] Result Analysis

[0080] High temperature resistance: Examples 1-3 performed well, with the lowest mass loss rate (0.3%) at high temperature and a significant reduction in bubble density.

[0081] Comparative Examples 1 to 3 showed poor thermal stability. Defoaming and foam suppression efficiency: Examples 1-3 had short defoaming times (approximately 20 seconds) and good defoaming performance. The bubble growth rate in Examples 1-3 was only approximately 5%, indicating excellent long-term foam suppression. In Comparative Example 1, the MOF was not methyl- or fluorinated, resulting in continuous bubble accumulation.

[0082] 3D printing applicability: The printed parts of Examples 1-3 have low porosity, high surface finish, and improved interlayer bonding strength, verifying the improvement of printing quality by the defoaming agent.

[0083] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A defoamer containing nano-MOF, characterized in that: The invention is composed of the following components in parts by weight: 1 to 5 parts of nano-MOF, 10 to 20 parts of hyperbranched polyethylsiloxane, 10 to 30 parts of fluoropolyether, 1 to 5 parts of modified hydrophobic silica, 1 to 5 parts of alkaline catalyst, 2 to 10 parts of emulsifier and 1 to 3 parts of stabilizer.

2. The defoamer containing nano-MOF according to claim 1, characterized in that: The nano-MOF is one or more of UiO-66-CH3, UiO-66-CF3, and UiO-66-F4.

3. The defoamer containing nano-MOF according to claim 1, characterized in that: The hyperbranched polyethylsiloxane has a molecular weight of 1000-50000 g / mol and a branching degree of 40-70%.

4. The defoamer containing nano-MOF according to claim 1, characterized in that: The fluoropolyether has an ethylene oxide / propylene oxide copolymer as the main chain, a fluoroalkyl side chain or a fluorinated terminal group, a molecular weight of 5000-100000 g / mol, and a fluorination degree of 30-70%.

5. The defoamer containing nano-MOF according to claim 1, characterized in that: The modified hydrophobic silica is one or more of methyl-modified hydrophobic silica, octadecyl-modified hydrophobic silica, siloxane-modified hydrophobic silica, and fluoroalkyl-modified hydrophobic silica.

6. The defoamer containing nano-MOF according to claim 1, characterized in that: The alkaline catalyst is one of sodium hydroxide, potassium hydroxide, potassium carbonate, ammonia water, sodium ethoxide, or a mixture of any of them.

7. The defoamer containing nano-MOF according to claim 1, characterized in that: The emulsifier is one or more of polyglycerol polyricinoleate, sucrose polyricinoleate, acetylated monoglyceride, lignin sulfonate grafted polyether, and hyperbranched polyglycerol ester.

8. The defoamer containing nano-MOF according to claim 1, characterized in that: The stabilizer is one or more of organic bentonite, polyamide wax, polyethylene glycol, acrylate copolymer, and nano clay.

9. A method for preparing a defoaming agent containing nano-MOF according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: (1) placing hyperbranched polyethylsiloxane, nano-MOF, modified hydrophobic silica, and an alkaline catalyst in a reaction kettle, controlling the temperature in the reaction kettle to 80-180° C. and stirring uniformly to prepare a first mixed solution; (2) adding a fluoropolyether and an emulsifier to the first mixed solution and stirring uniformly to obtain a second mixed solution; (3) Add a stabilizer to the second mixed solution and stir evenly to prepare a defoaming agent.

10. Use of the defoaming agent according to any one of claims 1 to 8 in 3D printing.

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