Composite damping emulsion, water-based damping vibration attenuation coating and preparation method of water-based damping vibration attenuation coating

Abstract

The invention provides a composite damping emulsion, a water-based damping vibration attenuation coating and a preparation method of the water-based damping vibration attenuation coating, and belongs to the technical field of damping coatings. The composite damping emulsion is prepared from a waterborne polyurethane emulsion and an organic silicon modified core-shell type acrylate emulsion; the organosilicone modified core-shell type acrylate emulsion is synthesized by adopting a seed semi-continuous emulsion polymerization method and introducing organosilicone. The water-based damping vibration attenuation coating is prepared from 15 to 100 parts of composite damping emulsion; 20 to 120 parts of a functional filler; 1 to 6 parts of nanofiber; 5 to 30 parts of a flame retardant; 5 to 40 parts of deionized water; 0.1 part to 0.6 part of a pH (Potential of Hydrogen) regulator; and 1.8 to 15.6 parts of an auxiliary agent. The invention provides a two-component composite damping emulsion composed of a waterborne polyurethane emulsion and an organic silicon modified core-shell type acrylate emulsion, the two components form a cross-linked network structure, the cross-linked network structure and the functional filler have a synergistic effect, and the functional filler is uniformly dispersed in the emulsion, so that the damping performance of the coating is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of damping coating technology, and specifically relates to a composite damping emulsion, a water-based damping vibration reduction coating, and a method for preparing the same. Background Technology

[0002] Damping and vibration-damping coatings are functional coatings that absorb vibration energy and reduce noise through the viscoelastic energy-dissipating properties of the material. They are widely used in rail transportation (high-speed rail, subway bodies and interiors), automotive industry (engine compartments, chassis, body panels), shipbuilding (cabins, decks), construction (machine rooms, pipelines, walls), and mechanical equipment (pumps, fans). Their core function is to reduce vibration noise by inhibiting the transmission of structural vibrations and converting vibration energy into heat dissipation, thereby improving equipment operational stability, environmental comfort, and structural lifespan. They are one of the key materials for vibration reduction and noise reduction in modern industrial and civil applications.

[0003] With increasing global environmental awareness and increasingly stringent environmental regulations in various countries (such as my country's "Standard for the Control of Unorganized Emissions of Volatile Organic Compounds" and "Technical Requirements for Coatings with Low Volatile Organic Compound Content"), traditional solvent-based damping and vibration-damping coatings, containing large amounts of volatile organic compounds (VOCs), not only cause air pollution during production, construction, and use but also endanger the health of operators, leading to gradual restrictions on their application. Against this backdrop, water-based damping and vibration-damping coatings, with their water-based dispersion medium, low VOC content, lack of irritating odor, high safety, and compliance with environmental trends, have become the mainstream direction for industry research and application. However, existing water-based damping and vibration-damping coatings still have significant shortcomings: First, their damping performance is insufficient, often using a single resin with a low loss factor and a narrow effective damping temperature range (usually only -10℃ to 30℃), making them difficult to adapt to extreme temperature environments. Second, it is difficult to balance mechanical properties and damping performance; plasticizers and other additives added to improve damping can easily lead to a decrease in coating adhesion, water resistance, and weather resistance, resulting in cracking and peeling. Third, they have poor stability during construction and storage; resin particles and functional fillers are prone to stratification and sedimentation, and drying is slow in high humidity environments, leading to the formation of bubbles and pinholes in the film. Although existing technologies have attempted to improve the coatings through composite resins and functional fillers, they suffer from problems such as poor compatibility of composite resins, complex filler dispersion processes, high costs, and environmental impact from some additives, failing to achieve the synergistic optimization of "high damping, wide temperature range, strong mechanical properties, high environmental friendliness, and easy construction." Therefore, developing a high-performance waterborne damping and vibration reduction coating with low VOC content, excellent environmental performance, high loss factor, wide damping temperature range, good mechanical properties and construction stability is the key to solving industry pain points and meeting the needs of high-end fields, and has important application value. Summary of the Invention

[0004] Therefore, the present invention aims to provide a composite damping emulsion, an aqueous damping and vibration reduction coating and a method for preparing the same, in order to solve at least one technical problem in the background art.

[0005] This invention is implemented as follows: The first aspect of this invention provides a composite damping emulsion comprising an aqueous polyurethane emulsion and an organosilicon-modified core-shell acrylate emulsion; the organosilicon-modified core-shell acrylate emulsion is synthesized using a seeded semi-continuous emulsion polymerization method with the introduction of organosilicon, comprising the following steps: S1. Prepare a core pre-emulsion composed of butyl acrylate, methyl methacrylate, styrene, solvent and emulsifier, a shell pre-emulsion composed of butyl acrylate, methyl methacrylate, styrene, acrylic acid, β-hydroxyethyl methacrylate, crosslinking agent, solvent and emulsifier, and an initiation system solution composed of initiator ammonium persulfate, buffer sodium bicarbonate and solvent. S2. First, take a portion of the aforementioned pre-emulsion and react it with a portion of the initiation system solution in a reactor at a higher temperature to prepare a seed emulsion; then, continuously add the remaining pre-emulsion and a portion of the initiation system solution to the seed emulsion, and carry out core-layer polymerization by maintaining the temperature to obtain a core-layer emulsion. S3. Organosilicon-modified shell polymerization: The shell pre-emulsion and the remaining initiation system solution are simultaneously and continuously added to the core emulsion to carry out the shell polymerization reaction. Silane coupling agent is added in the middle and late stages of the shell polymerization reaction. After all materials have been added, the mixture is kept at a constant temperature for curing to finally obtain the organosilicon-modified core-shell acrylate emulsion.

[0006] Preferably, the mass ratio of the waterborne polyurethane emulsion to the silicone-modified core-shell acrylate emulsion is 1:1 to 5.

[0007] Preferably, step S1 specifically includes: S11. Weigh out 10-25 parts of butyl acrylate, 10-30 parts of methyl methacrylate, 1-5 parts of styrene monomer, 0.1-1 parts of sodium dodecylbenzene sulfonate emulsifier, 0.1-0.5 parts of octylphenol polyoxyethylene ether OP-10 emulsifier, and 20-50 parts of deionized water in sequence, mix and stir for 30-40 minutes to prepare a core pre-emulsion. S12. Weigh 25-40 parts of butyl acrylate, 20-40 parts of methyl methacrylate, 1-5 parts of styrene, 1-4 parts of acrylic acid, 1-5 parts of β-hydroxyethyl methacrylate, 1-3 parts of crosslinking agent divinylbenzene monomer, 0.1-0.2 parts of emulsifier sodium dodecylbenzenesulfonate, 0.1-0.5 parts of emulsifier octylphenol polyoxyethylene ether op-10, and 50-100 parts of deionized water, mix and stir for 30-50 minutes to prepare a shell pre-emulsion. S13. Weigh 0.5 to 1.5 parts of initiator ammonium persulfate and 0.5 to 1.5 parts of buffer sodium bicarbonate, dissolve them in 40 to 80 parts of deionized water, stir well, and prepare an initiation system solution.

[0008] Preferably, step S2 specifically includes: S21. Weigh 20 to 40 parts of deionized water bottom solution and pour it into a four-necked flask; then add 40% to 60% of the nuclear pre-emulsion and 5 to 8 parts of the initiation system solution, heat to 60℃-100℃, stir the reaction until blue light appears in the flask, keep warm for 20 to 40 minutes to obtain the seed emulsion. S22. Add the remaining pre-emulsion of the nucleus to the seed emulsion, and simultaneously add 6 to 12 parts of the initiation system solution. The addition shall be completed in 30 to 50 minutes. After the addition is completed, keep the reaction at the temperature for 0.8 to 1.5 hours to obtain the nucleus emulsion.

[0009] Preferably, step S3 specifically includes: Simultaneously add the shell pre-emulsion and the remaining initiation system solution to the core emulsion. When the shell pre-emulsion is about 25% to 35% remaining, simultaneously add 0.2 to 0.5 parts of silane coupling agent Kh570. The entire shell pre-emulsion is added over 1.5 to 2.5 hours. After the addition is complete, maintain the temperature at 45°C to 60°C for 0.8 to 1.2 hours. After the reaction is complete, cool the system to room temperature, add an appropriate amount of ammonia to adjust the pH of the system to neutral, and filter the material through 100-200 mesh gauze.

[0010] A second aspect of the present invention provides an aqueous damping and vibration-damping coating, comprising the following raw material components in parts by weight: 15 to 100 parts of composite damping emulsion; Functional filler: 20-120 parts; 1 to 6 parts nanofibers; 5 to 30 parts flame retardant; 5 to 40 parts deionized water; pH adjuster 0.1 to 0.6 parts; Additives: 1.8 to 15.6 parts.

[0011] Preferably, the additive comprises the following components in parts by weight: Dispersant 0.5 to 4 parts; 0.2 to 0.6 parts of wetting agent; Anti-aging agent: 0.1 to 2 parts; Defoamer 0.2 to 2 parts; Antifreeze 0.3 to 2 parts; Thickener 0.5 to 5 parts.

[0012] Preferably, the functional filler is at least one selected from mica powder, calcium carbonate, titanium dioxide, vermiculite, wollastonite, and graphite powder; The nanofibers are at least one of polyester fiber, polypropylene fiber, and polyethylene fiber; the length of the nanofibers is 1 mm to 4 mm. The flame retardant is at least one of polymeric brominated flame retardant, aluminum hydroxide, and magnesium hydroxide. The pH adjuster is at least one of 2-amino-2-methyl-1-propanol and dimethylethanolamine.

[0013] Preferably, the dispersant is a sodium acrylate dispersant; The wetting agent is at least one of sodium dodecylbenzenesulfonate and diisooctyl succinate sulfonate; The anti-aging agent is at least one of antioxidant 2246 and anti-aging agent 4010; The defoamer is at least one of silicone defoamers and mineral oil defoamers; The antifreeze agent is at least one of ethylene glycol and propylene glycol; The thickener is at least one of hydroxyethyl cellulose, acrylate thickener, and associative polyurethane thickener.

[0014] A third aspect of the present invention provides a method for preparing a water-based damping and vibration-damping coating, comprising the following steps: Add the preset weights of waterborne polyurethane emulsion, silicone-modified core-shell acrylate emulsion, and deionized water to a water bath reactor, and stir and disperse thoroughly for 15 min to 50 min. The water bath temperature is 20℃ to 70℃, and the stirring speed is 250 rpm to 650 rpm. Then add the pH adjuster, dispersant, wetting agent, anti-aging agent, antifreeze agent, part of the defoamer, and part of the thickener in sequence, and stir and disperse for 10 to 30 minutes; Add functional fillers, flame retardants, and nanofibers during the stirring process, and continue stirring for 20 to 50 minutes. Finally, add the remaining defoamer and thickener and continue stirring for 15 to 35 minutes to obtain the water-based damping and vibration reduction coating.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention provides a two-component composite damping emulsion composed of an aqueous polyurethane emulsion and an organosilicon-modified core-shell acrylate emulsion. The two components form a cross-linked network structure, which works synergistically with the functional filler. The functional filler is uniformly dispersed in the emulsion, which significantly improves the damping performance of the coating.

[0016] 2. The water-based damping and vibration reduction coating provided by this invention has good mechanical properties, flame retardancy, environmental friendliness, practicality, and durability. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0018] The composite damping emulsion includes aqueous polyurethane emulsion and silicone-modified core-shell acrylate emulsion; the mass ratio of aqueous polyurethane emulsion to silicone-modified core-shell acrylate emulsion is 1:1 to 5, for example, it can be 1:1, 1:2.5, or 1:5; the following examples use 1:2.5 as an example, but are not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0019] The organosilicon-modified core-shell acrylate emulsion is synthesized using a seeded semi-continuous emulsion polymerization method with the introduction of organosilicon, comprising the following steps: S1. Prepare a core pre-emulsion composed of butyl acrylate, methyl methacrylate, styrene, solvent and emulsifier, a shell pre-emulsion composed of butyl acrylate, methyl methacrylate, styrene, acrylic acid, β-hydroxyethyl methacrylate, crosslinking agent, solvent and emulsifier, and an initiation system solution composed of initiator ammonium persulfate, buffer sodium bicarbonate and solvent. Specifically, it includes: S11. Weigh out 10-25 parts of butyl acrylate, 10-30 parts of methyl methacrylate, 1-5 parts of styrene monomer, 0.1-1 parts of sodium dodecylbenzene sulfonate emulsifier, 0.1-0.5 parts of octylphenol polyoxyethylene ether OP-10 emulsifier, and 20-50 parts of deionized water in sequence, mix and stir for 30-40 minutes to prepare a core pre-emulsion. S12. Weigh 25-40 parts of butyl acrylate, 20-40 parts of methyl methacrylate, 1-5 parts of styrene, 1-4 parts of acrylic acid, 1-5 parts of β-hydroxyethyl methacrylate, 1-3 parts of crosslinking agent divinylbenzene monomer, 0.1-0.2 parts of emulsifier sodium dodecylbenzenesulfonate, 0.1-0.5 parts of emulsifier octylphenol polyoxyethylene ether op-10, and 50-100 parts of deionized water, mix and stir for 30-50 minutes to prepare a shell pre-emulsion. S13. Weigh 0.5 to 1.5 parts of initiator ammonium persulfate and 0.5 to 1.5 parts of buffer sodium bicarbonate, dissolve them in 40 to 80 parts of deionized water, stir well, and prepare an initiation system solution.

[0020] S2. First, take a portion of the aforementioned pre-emulsion and react it with a portion of the initiation system solution in a reactor at a higher temperature to prepare a seed emulsion; then, continuously add the remaining pre-emulsion and a portion of the initiation system solution to the seed emulsion, and carry out core-layer polymerization by maintaining the temperature to obtain a core-layer emulsion. Specifically, it includes: S21. Weigh 20 to 40 parts of deionized water bottom solution and pour it into a 500 ml four-necked flask equipped with a thermometer with a range of 100℃, a reflux condenser and a stirrer; then add 40% to 60% of the nuclear pre-emulsion and 5 to 8 parts of the initiation system solution, heat to 60℃ to 100℃, stir the reaction until blue light appears in the flask, keep warm for 20 to 40 minutes to obtain the seed emulsion; S22. Add the remaining pre-emulsion of the nucleus to the seed emulsion, and simultaneously add about 6 to 12 parts of the initiation system solution. The addition is completed in 30 to 50 minutes. After the addition is completed, keep the reaction at the temperature for 0.8 to 1.5 hours to obtain the nucleus emulsion.

[0021] S3. Organosilicon-modified shell polymerization: The shell pre-emulsion and the remaining initiation system solution are simultaneously and continuously added dropwise to the core emulsion to carry out the shell polymerization reaction. In the middle and late stages of the shell polymerization reaction, the silane coupling agent is introduced into the reaction system. After all the materials have been added, the mixture is kept at a constant temperature for curing to finally obtain the organosilicon-modified core-shell acrylate emulsion.

[0022] Specifically, it includes: Simultaneously add the shell pre-emulsion and the remaining initiation system solution to the core emulsion. When the shell pre-emulsion is about 25% to 35% remaining, simultaneously add 0.2 to 0.5 parts of silane coupling agent Kh570. The entire shell pre-emulsion is added over 1.5 to 2.5 hours. After the addition is complete, maintain the temperature at 45°C to 60°C for 0.8 to 1.2 hours. After the reaction is complete, cool the system to room temperature, add an appropriate amount of ammonia to adjust the pH of the system to neutral, and filter the material through 100-200 mesh gauze.

[0023] The organosilicon-modified core-shell acrylate emulsion prepared by this invention significantly optimizes the physicochemical properties of the emulsion after film formation through the dual synergistic effect of core-shell structure design and organosilicon modification. When combined with waterborne polyurethane emulsion, the comprehensive application performance of the coating is further improved by leveraging the complementary advantages and interfacial interaction of the two emulsions.

[0024] The specific mechanism is as follows: This invention utilizes a seed-based semi-continuous emulsion polymerization method to construct a core-shell structure, achieving functional partitioning of a soft core and a hard core, thus providing excellent damping performance and mechanical stability for the coating. The core layer uses butyl acrylate as the main soft monomer, combined with methyl methacrylate and styrene to form a flexible core. This structure endows the film-forming material with good chain segment mobility, allowing it to dissipate energy through chain segment friction and deformation under external force or vibration, thereby improving the coating's damping and vibration reduction performance. The shell layer primarily uses hard monomers such as methyl methacrylate, supplemented with functional monomers such as acrylic acid and β-hydroxyethyl methacrylate, forming a rigid outer shell. This not only improves the film-forming material's hardness, abrasion resistance, and scratch resistance but also enhances the adhesion between the emulsion and the substrate through polar groups such as carboxyl and hydroxyl groups in the shell layer. Simultaneously, it provides reactive sites for subsequent silicone modification and waterborne polyurethane composites. The silane coupling agent, added dropwise during the later stages of shell polymerization, was successfully grafted onto the surface of the acrylate shell through chemical bonding, achieving precise modification of the acrylate emulsion by organosilicon. On one hand, the silicon-oxygen bonds (Si-O) in the silane coupling agent possess extremely high bond energy and chemical stability, capable of replacing the carbon-carbon bonds (CC) in the acrylate molecules to construct a more stable film-forming network. This significantly improves the coating's weather resistance, UV aging resistance, and high-temperature resistance, effectively preventing aging phenomena such as yellowing, chalking, and cracking during long-term use. On the other hand, organosilicon molecules have extremely low surface energy, enabling them to migrate to the surface of the coating film layer, forming a dense hydrophobic protective film. This reduces the surface water absorption rate of the coating, improving its water resistance and corrosion resistance, while also enhancing its leveling and stain resistance. Furthermore, the cross-linking effect of the silane coupling agent further densifies the film-forming network, reduces intrafilm porosity, and enhances the coating's barrier properties, preventing external corrosive media such as moisture and oxygen from penetrating the substrate. The combination of waterborne polyurethane emulsion and silicone-modified core-shell acrylic emulsion is not a simple physical mixture, but rather a synergistic and stable composite system formed through interfacial interactions, further enhancing the coating performance in all aspects, specifically in the following ways: The polar groups such as carboxyl and hydroxyl groups in the shell layer of silicone-modified core-shell acrylate emulsions can undergo hydrogen bonding or chemical reactions with the amino and hydroxyl groups in the molecular chains of waterborne polyurethane emulsions (such as the salt formation reaction between carboxyl and amino groups, and the crosslinking reaction between hydroxyl and isocyanate groups, if the waterborne polyurethane is a system containing isocyanate groups), significantly improving the compatibility of the two emulsions. This interfacial interaction effectively prevents the two emulsions from delamination and phase separation during film formation, ensuring the formation of a uniform, dense, and continuous film layer, laying the foundation for the stable performance of the coating. Especially within the preferred mass ratio of waterborne polyurethane to silicone-modified core-shell acrylate emulsion of 1:1 to 5, the molecular chains of the two emulsions can form a uniformly interwoven network structure, achieving a precise balance between rigidity and flexibility. Waterborne polyurethane emulsions contain numerous urethane groups in their molecular chains, resulting in strong intermolecular hydrogen bonding and excellent elasticity and energy absorption capabilities. Meanwhile, the soft core structure of silicone-modified core-shell acrylate emulsions provides superior segmental friction energy dissipation characteristics. When combined, the strong hydrogen bonding of polyurethane synergistically enhances the segmental mobility of the acrylate soft core, significantly increasing the internal friction loss of the film. This, in turn, strengthens the coating's damping performance, broadens its damping temperature range, and enables it to meet vibration reduction requirements in a wider range of temperature environments. Simultaneously, the rigid outer shell of the core-shell structure, combined with the high strength of polyurethane, avoids the insufficient mechanical strength of purely flexible systems, achieving a simultaneous improvement in both damping performance and mechanical strength.

[0025] The water-based damping and vibration-damping coating comprises the following raw material components in parts by weight: 15 to 100 parts of the above-mentioned composite damping emulsion; 20 to 120 parts of functional filler; 1 to 6 parts of nanofiber; 5 to 30 parts of flame retardant; 5 to 40 parts of deionized water; 0.1 to 0.6 parts of pH adjuster; 0.5 to 4 parts of dispersant; 0.2 to 0.6 parts of wetting agent; 0.1 to 2 parts of anti-aging agent; 0.2 to 2 parts of defoamer; 0.3 to 2 parts of antifreeze agent; and 0.5 to 5 parts of thickener.

[0026] The functional filler is at least one of mica powder, calcium carbonate, titanium dioxide, vermiculite, wollastonite, and graphite powder; the nanofiber is at least one of polyester fiber, polypropylene fiber, and polyethylene fiber; the length of the nanofiber is 1 mm to 4 mm; the flame retardant is at least one of polymeric bromine-based flame retardants (such as flame retardant 6001 and flame retardant 6003), aluminum hydroxide, and magnesium hydroxide; the pH adjuster is at least one of 2-amino-2-methyl-1-propanol and dimethylethanolamine.

[0027] In specific implementation, the additives (dispersants, wetting agents, anti-aging agents, defoamers, antifreeze agents, and thickeners) are functional additives permitted in the art. For example, the dispersant may be a sodium acrylate dispersant; the wetting agent may be at least one of sodium dodecylbenzene sulfonate and diisooctyl succinate sulfonate; the anti-aging agent may be at least one of antioxidant 2246 and antioxidant 4010; the defoamer may be at least one of silicone defoamer and mineral oil defoamer; the antifreeze agent may be at least one of ethylene glycol and propylene glycol; and the thickener may be at least one of hydroxyethyl cellulose, acrylate thickener, and associative polyurethane thickener. In the following embodiments, the dispersant is sodium polyacrylate, the wetting agent is diisooctyl succinate sulfonate, the anti-aging agent is antioxidant 4010, the defoamer is an organosilicon defoamer, the antifreeze agent is propylene glycol, and the thickener is an acrylate thickener, but not limited to the listed additives and their corresponding functional substances. Other additives and functional substances not listed in the art are also applicable.

[0028] A method for preparing water-based damping and vibration-damping coatings includes the following steps: Add the preset weights of waterborne polyurethane emulsion, silicone-modified core-shell acrylate emulsion, and deionized water to a water bath reactor, and stir and disperse thoroughly for 15 min to 50 min. The water bath temperature is 20℃ to 70℃ and the stirring speed is 250 rpm to 650 rpm. Then add the pH adjuster, dispersant, wetting agent, anti-aging agent, antifreeze agent, part of the defoamer (about 1 / 2), and part of the thickener (about 1 / 2) in sequence, and stir and disperse for 10 min to 30 min; Add functional fillers, flame retardants, and nanofibers during the stirring process, and continue stirring for 20 to 50 minutes. Finally, add the remaining defoamer and thickener and continue stirring for 15 to 35 minutes to obtain the water-based damping and vibration reduction coating.

[0029] Example 1 A method for preparing water-based damping and vibration-damping coatings includes the following steps: S100, Synthesis of organosilicon-modified core-shell acrylate emulsion, the specific synthesis steps are as follows: (1) Preparation of nuclear preemulsion: Weigh 18 parts of butyl acrylate (BA), 20 parts of methyl methacrylate (MMA), 3 parts of styrene (St) monomer, 0.5 parts of anionic emulsifier sodium dodecylbenzenesulfonate (SDBS), 0.3 parts of nonionic emulsifier octylphenol polyoxyethylene ether OP-10, and 35 parts of deionized water in sequence and mix for 35 minutes to prepare nuclear preemulsion for later use; (2) Preparation of shell preemulsion: Weigh 32 parts butyl acrylate (BA), 30 parts methyl methacrylate (MMA), 3 parts styrene (St), 2.5 parts acrylic acid (AA), 3 parts β-hydroxyethyl methacrylate (HEMA), 2 parts crosslinking agent divinylbenzene (DVB) monomer, 0.15 parts emulsifier SDBS, 0.3 parts emulsifier octylphenol polyoxyethylene ether op-10, and 75 parts deionized water and mix for 40 min to prepare shell preemulsion for later use; (3) Preparation of the initiation system solution: Weigh 1 part of initiator ammonium persulfate (APS) and 1 part of buffer sodium bicarbonate (NaHCO3), dissolve them in 60 parts of deionized water, stir evenly, and prepare the initiation system solution for later use; (4) Preparation of seed emulsion: Weigh 30 parts of deionized water bottom solution and pour it into a 500ml four-necked flask equipped with a thermometer with a range of 100℃, a reflux condenser and a stirrer; then add about 1 / 2 of the nuclear pre-emulsion and 7 parts of the initiation system solution, heat to 80℃, stir the reaction until blue light appears in the flask, keep warm for 30min, and obtain seed emulsion; (5) Preparation of core emulsion: The remaining pre-emulsion of the core is added dropwise to the seed emulsion, and about 9 parts of the initiation system solution are added dropwise at the same time. The addition is completed in about 40 minutes. After the addition is completed, the reaction is kept warm for 1.2 hours to obtain the core emulsion.

[0030] (6) Preparation of shell emulsion: The shell pre-emulsion and the remaining initiator solution are added dropwise to the core emulsion. When the shell pre-emulsion is about 30% remaining, 0.3 parts of silane coupling agent Kh570 are added dropwise. The entire shell pre-emulsion is added dropwise over 2 hours. After the addition is complete, the reaction is kept at 60°C for 1 hour. After the reaction is complete, the system is cooled to room temperature, and an appropriate amount of ammonia is added to adjust the pH of the system to neutral. The system is then filtered through 150-mesh gauze.

[0031] S200. According to the component settings in Table 1, add the corresponding weights of waterborne polyurethane emulsion, silicone-modified core-shell acrylate emulsion, and deionized water to a water bath reactor, and stir and disperse thoroughly for 30 minutes. The water bath temperature is 50℃ and the stirring speed is 450 rpm. S300, then add pH adjuster, dispersant, wetting agent, anti-aging agent, antifreeze agent, part of defoamer (about 1 / 2), and part of thickener (about 1 / 2) in sequence, and stir and disperse for 20 minutes; S400, add functional filler, flame retardant, and nanofibers (1mm~4mm in length) during the stirring process, and continue stirring for 40 minutes; S500, and finally add the remaining defoamer and thickener and continue stirring for 25 minutes to obtain the water-based damping and vibration reduction coating.

[0032] Table 1

[0033] Example 2 The only difference between this embodiment and Embodiment 1 is the material of the functional filler, as shown in Table 1. All other conditions and steps are the same as in Embodiment 1.

[0034] Example 3 The only difference between this embodiment and Embodiment 1 is the material and amount of the functional filler, as shown in Table 1. All other conditions and steps are the same as in Embodiment 1.

[0035] Comparative Example 1 The only difference between this comparative example and Example 1 is that the composite damping emulsion is replaced with a single aqueous polyurethane emulsion, as shown in Table 1. All other conditions and steps are the same as in Example 1.

[0036] Comparative Example 2 The only difference between this comparative example and Example 1 is that the composite damping emulsion is replaced with a single organosilicon-modified core-shell acrylate emulsion, as shown in Table 1. All other conditions and steps are the same as in Example 1.

[0037] Comparative Example 3 The only difference between this comparative example and Example 1 is that the silicone-modified core-shell acrylate emulsion in the composite damping emulsion is replaced with an unmodified acrylate emulsion, as shown in Table 1. All other conditions and steps are the same as in Example 1.

[0038] The damping coatings obtained from Examples 1 to 3 and Comparative Examples 1 to 3 were used to make coatings, and their performance was tested. The coatings were compared with the damping and vibration reduction coating Air3101 (commercial group) from Qingdao Aierjiajia New Material Co., Ltd., a well-known domestic brand. The results are shown in Table 2.

[0039] Consistency, drying time, flexibility, X-cut test, resistance to liquid media, heat resistance, and 45°C burning test were tested in accordance with the standard Q / CR581-2017 "Technical Conditions for Coatings for Railway Passenger Cars". The ozone aging performance was tested according to GB / T 7762-2014 "Static Tensile Test for Ozone Cracking Resistance of Vulcanized Rubber or Thermoplastic Rubber". Low-temperature brittleness was tested according to GB / T 1682-2014 "Determination of Low-Temperature Brittleness of Vulcanized Rubber - Single Specimen Method". Flame retardancy was tested according to GB / T 10707-2008 "Determination of the flammability of rubber"; The mildew resistance rating was tested according to the standard HGT / 4301-2012 "Test Method for Mildew Resistance of Rubber"; The composite damping loss factor was tested according to the standard GB / T18258-2000 "Test Method for Damping Performance of Damping Materials".

[0040] According to GB / T1727-2021 "General Method for Preparing Coating Films", the test panels were surface-treated, and the damping coatings obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were applied using a scraping method to prepare coating films. The dry film thickness should be (2.0±0.2) mm. After coating, the test panels were dried at room temperature (23.5±2)℃ for 10 days, and then the condensation performance was tested. Condensation performance: The anti-condensation damping coating was applied to an area of ​​60 mm². 2 After the metal plate is completely dried, it is placed vertically in an environment with a temperature of 10℃ and a relative humidity of 80%, and the condensation on the surface is observed after 48 hours.

[0041] Table 2

[0042] The results in Table 2 show that the water-based damping and vibration-damping coating prepared by this invention has excellent mechanical properties, chemical resistance, non-flammability, and damping performance.

[0043] Comparing Comparative Example 1 with Example 1, the results showed that the consistency (13.6 cm) of Comparative Example 1 was greater than that of Example 1 (13.3 cm), the drying time (38 h) was longer than that of Example 1 (30 h), and the composite loss factor at -10℃, 20℃ and 50℃ was lower than that of Example 1. This indicates that the coating of Comparative Example 1 is inferior to that of Example 1 in terms of consistency control, drying efficiency and damping performance.

[0044] Comparing Comparative Example 2 with Example 1, the results showed that the consistency (13.4 cm) of Comparative Example 2 was slightly greater than that of Example 1 (13.3 cm), the drying time (36 h) was longer than that of Example 1 (30 h), and the composite loss factor at each temperature was also lower than that of Example 1. This indicates that the coating of Comparative Example 2 dried slower and had weaker damping performance than that of Example 1.

[0045] Comparing Comparative Example 3 with Example 1, the results showed that the two had the same consistency, but the drying time of Comparative Example 3 (35h) was longer than that of Example 1 (30h), and the composite loss factor at each temperature was lower than that of Example 1, indicating that the coating drying efficiency and damping performance of Comparative Example 3 were not as good as those of Example 1.

[0046] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A composite damping emulsion, characterized in that, The composite damping emulsion includes an aqueous polyurethane emulsion and an organosilicon-modified core-shell acrylate emulsion. The organosilicon-modified core-shell acrylate emulsion is synthesized using a seeded semi-continuous emulsion polymerization method with the introduction of organosilicon, comprising the following steps: S1. Prepare a core pre-emulsion composed of butyl acrylate, methyl methacrylate, styrene, solvent and emulsifier, a shell pre-emulsion composed of butyl acrylate, methyl methacrylate, styrene, acrylic acid, β-hydroxyethyl methacrylate, crosslinking agent, solvent and emulsifier, and an initiation system solution composed of initiator ammonium persulfate, buffer sodium bicarbonate and solvent. S2. First, take a portion of the aforementioned pre-emulsion and react it with a portion of the initiation system solution in a reactor at a higher temperature to prepare a seed emulsion; then, continuously add the remaining pre-emulsion and a portion of the initiation system solution to the seed emulsion, and carry out core-layer polymerization by maintaining the temperature to obtain a core-layer emulsion. S3. Organosilicon-modified shell polymerization: The shell pre-emulsion and the remaining initiation system solution are simultaneously and continuously added to the core emulsion to carry out the shell polymerization reaction. Silane coupling agent is added in the middle and late stages of the shell polymerization reaction. After all materials have been added, the mixture is kept at a constant temperature for curing to finally obtain the organosilicon-modified core-shell acrylate emulsion.

2. The composite damping emulsion according to claim 1, characterized in that, The mass ratio of waterborne polyurethane emulsion to silicone-modified core-shell acrylate emulsion is 1:1~5.

3. The composite damping emulsion according to claim 1, characterized in that, The specific steps in S1 include: S11. Weigh out 10-25 parts of butyl acrylate, 10-30 parts of methyl methacrylate, 1-5 parts of styrene monomer, 0.1-1 parts of sodium dodecylbenzene sulfonate emulsifier, 0.1-0.5 parts of octylphenol polyoxyethylene ether OP-10 emulsifier, and 20-50 parts of deionized water in sequence, mix and stir for 30-40 minutes to prepare a core pre-emulsion. S12. Weigh 25-40 parts of butyl acrylate, 20-40 parts of methyl methacrylate, 1-5 parts of styrene, 1-4 parts of acrylic acid, 1-5 parts of β-hydroxyethyl methacrylate, 1-3 parts of crosslinking agent divinylbenzene monomer, 0.1-0.2 parts of emulsifier sodium dodecylbenzenesulfonate, 0.1-0.5 parts of emulsifier octylphenol polyoxyethylene ether op-10, and 50-100 parts of deionized water, mix and stir for 30-50 minutes to prepare a shell pre-emulsion. S13. Weigh 0.5 to 1.5 parts of initiator ammonium persulfate and 0.5 to 1.5 parts of buffer sodium bicarbonate, dissolve them in 40 to 80 parts of deionized water, stir well, and prepare an initiation system solution.

4. The composite damping emulsion according to claim 3, characterized in that, The specific steps in S2 include: S21. Weigh 20 to 40 parts of deionized water bottom solution and pour it into a four-necked flask; then add 40% to 60% of the nuclear pre-emulsion and 5 to 8 parts of the initiation system solution, heat to 60℃-100℃, stir the reaction until blue light appears in the flask, keep warm for 20 to 40 minutes to obtain the seed emulsion. S22. Add the remaining pre-emulsion of the nucleus to the seed emulsion, and simultaneously add 6 to 12 parts of the initiation system solution. The addition shall be completed in 30 to 50 minutes. After the addition is completed, keep the reaction at the temperature for 0.8 to 1.5 hours to obtain the nucleus emulsion.

5. The composite damping emulsion according to claim 4, characterized in that, The steps in S3 specifically include: Simultaneously add the shell pre-emulsion and the remaining initiation system solution to the core emulsion. When the shell pre-emulsion is about 25% to 35% remaining, simultaneously add 0.2 to 0.5 parts of silane coupling agent. The entire shell pre-emulsion is added dropwise over 1.5 to 2.5 hours. After the addition is complete, maintain the temperature at 45°C to 60°C for 0.8 to 1.2 hours. After the reaction is complete, cool the system to room temperature, add an appropriate amount of ammonia water to adjust the pH of the system to neutral, and filter the material through 100-200 mesh gauze.

6. A water-based damping and vibration-damping coating, characterized in that, The water-based damping and vibration-damping coating comprises the following raw material components in parts by weight: 15 to 100 parts of the composite damping emulsion according to any one of claims 1 to 5; Functional filler: 20-120 parts; 1 to 6 parts nanofibers; 5 to 30 parts flame retardant; 5 to 40 parts deionized water; pH adjuster 0.1 to 0.6 parts; Additives: 1.8 to 15.6 parts.

7. The water-based damping and vibration-damping coating according to claim 6, characterized in that, The additive comprises the following components in parts by weight: Dispersant 0.5 to 4 parts; 0.2 to 0.6 parts of wetting agent; Anti-aging agent: 0.1 to 2 parts; Defoamer 0.2 to 2 parts; Antifreeze 0.3 to 2 parts; Thickener 0.5 to 5 parts.

8. The water-based damping and vibration-damping coating according to claim 6, characterized in that, The functional filler is selected from at least one of mica powder, calcium carbonate, titanium dioxide, vermiculite, wollastonite, and graphite powder; The nanofibers are at least one of polyester fiber, polypropylene fiber, and polyethylene fiber; the length of the nanofibers is 1 mm to 4 mm. The flame retardant is at least one of polymeric brominated flame retardant, aluminum hydroxide, and magnesium hydroxide. The pH adjuster is at least one of 2-amino-2-methyl-1-propanol and dimethylethanolamine.

9. The water-based damping and vibration-damping coating according to claim 6, characterized in that, The dispersant used is a sodium acrylate dispersant; The wetting agent is at least one of sodium dodecylbenzenesulfonate and diisooctyl succinate sulfonate; The anti-aging agent is at least one of antioxidant 2246 and anti-aging agent 4010; The defoamer is at least one of silicone defoamers and mineral oil defoamers; The antifreeze agent is at least one of ethylene glycol and propylene glycol; The thickener is at least one of hydroxyethyl cellulose, acrylate thickener, and associative polyurethane thickener.

10. The method for preparing the water-based damping and vibration-damping coating according to any one of claims 6 to 9, characterized in that, The preparation method includes the following steps: Add the preset weights of waterborne polyurethane emulsion, silicone-modified core-shell acrylate emulsion, and deionized water to a water bath reactor, and stir and disperse thoroughly for 15 min to 50 min. The water bath temperature is 20℃ to 70℃, and the stirring speed is 250 rpm to 650 rpm. Then add the pH adjuster, dispersant, wetting agent, anti-aging agent, antifreeze agent, part of the defoamer, and part of the thickener in sequence, and stir and disperse for 10 to 30 minutes; Add functional fillers, flame retardants, and nanofibers during the stirring process, and continue stirring for 20 to 50 minutes. Finally, add the remaining defoamer and thickener and continue stirring for 15 to 35 minutes to obtain the water-based damping and vibration reduction coating.

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