Vibration attenuation damping material and preparation method thereof

Abstract

The invention relates to a vibration attenuation damping material and a preparation method thereof, and belongs to the technical field of vibration attenuation materials. The vibration attenuation damping material is prepared from the following raw materials: matrix resin emulsion and damping filler, wherein the matrix resin is a modified polyurethane-acrylate interpenetrating network polymer, and monomers of the modified polyurethane-acrylate interpenetrating network polymer comprise polyether glycol, isocyanate, methyl methacrylate and butyl acrylate; the damping filler comprises a core-shell structure A-B compound and a layered inorganic filler; a is selected from multiwalled carbon nanotubes, graphene, carbon fibers and nano titanium dioxide, and B is selected from nitrile rubber, styrene butadiene rubber, chloroprene rubber and carboxylated styrene butadiene rubber; the dosage of the A-B compound with the core-shell structure is 10-20% of the mass of methyl methacrylate. The material disclosed by the invention has relatively good vibration damping performance at different temperatures, has excellent weather resistance and rainwater resistance, can be suitable for different application environments, and has a very good application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of damping materials, and in particular to a damping material and a preparation method thereof. Background Art

[0002] In the current research and application of damping materials, with the continuous improvement of vibration control requirements in fields such as industrial equipment, precision instruments, and building structures, the market demand for damping materials that can be conveniently pasted on the surfaces of various equipment and can effectively suppress low-frequency vibrations has increased significantly. However, existing adhesive damping materials generally have the problem of insufficient energy dissipation capacity in the low-frequency band, making it difficult to effectively attenuate the structural resonance and noise propagation caused by low-frequency vibrations, resulting in a decline in equipment stability and the comfort of the use environment. At the same time, for outdoor or complex working conditions, the material also needs to maintain stable performance under the combined action of multiple factors such as long-term ultraviolet radiation, extreme temperature cycling, drastic humidity fluctuations, and rain erosion. Traditional materials often show phenomena such as delamination, aging, or damping property decline due to insufficient weather resistance.

[0003] The commonly used damping materials in the prior art have some disadvantages: First, their performance limitations are prominent. Traditional materials have a narrow working temperature range. They are prone to softening and losing their damping ability in high-temperature environments, and their brittleness increases at low temperatures, making it difficult to maintain a stable damping effect in a wide temperature range. Especially, they have insufficient noise suppression and mechanical damage protection capabilities for low-frequency vibrations. Second, their weather resistance is poor. The existing additive systems lack the synergistic protection against multiple environmental factors such as ultraviolet rays, oxygen, and rainwater, resulting in problems such as oxidative degradation, aging cracking, etc. in outdoor applications. The mechanical properties and damping characteristics continuously decline, and the service life is greatly shortened. Third, the accuracy of regulating the glass transition temperature (Tg) is insufficient. Existing methods are difficult to achieve precise temperature control through the synergistic action of multiple factors. The thermodynamic response of the material has a low degree of matching with the complex environmental requirements, severely restricting its adaptability in harsh scenarios such as aerospace and rail transit.

[0004] In view of the above problems, there is an urgent need to develop a new type of damping material with excellent vibration damping performance in a wide temperature range, and excellent synergistic performance in anti-aging, resistance to humidity and heat alternation, and resistance to rain erosion, so as to meet the dual requirements of modern industry for vibration and noise reduction and long-term reliability. Summary of the Invention

[0005] The purpose of the present invention is to provide a damping material and a preparation method thereof by overcoming the deficiencies of the prior art. The damping material provided by the present invention has vibration damping performance in a wide temperature range, excellent weather resistance and rain resistance, and good application prospects.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a vibration damping material, and the raw materials for preparing the vibration damping material include a matrix resin emulsion and a damping filler;

[0008] The matrix resin in the matrix resin emulsion is a modified polyurethane-acrylate interpenetrating network polymer, and the monomers of the modified polyurethane-acrylate interpenetrating network polymer include polyether diol, isocyanate, methyl methacrylate and butyl acrylate;

[0009] The damping filler includes a core-shell structure A-B composite and a layered inorganic filler; in the core-shell structure A-B composite, substance A is at least one of multi-walled carbon nanotubes, graphene, carbon fiber, and nano-titanium dioxide, and substance B is at least one of nitrile rubber, styrene-butadiene rubber, chloroprene rubber, and carboxy styrene-butadiene rubber;

[0010] The dosage of the core-shell structure A-B composite is 10-20% of the mass of the methyl methacrylate.

[0011] The present invention mainly regulates the comprehensive performance of the vibration damping material by combining a specific matrix resin and a damping filler combination, so that the material has good vibration damping effect in a wide temperature range, an appropriate glass transition temperature, and at the same time takes into account excellent weather resistance and rain resistance.

[0012] Selecting a modified polyurethane-acrylate interpenetrating network polymer (abbreviated as PU-IPN-PA) as the matrix resin can accurately control its glass transition temperature (Tg), which is crucial for the vibration damping material to be used at different temperatures. The present invention mainly uses polyether diol and isocyanate to prepare modified polyurethane, and then introduces methyl methacrylate and butyl acrylate to polymerize to obtain a special interpenetrating network structure, which not only endows the material with good low-frequency vibration damping performance, but also provides a basis for its weather resistance and rain resistance. Among them, the flexible segment of polyurethane and the rigid segment of acrylate are intertwined with each other, enhancing the overall stability of the material and enabling it to better resist the erosion of external environmental factors.

[0013] The damping filler defined by the present invention includes a core-shell structure A-B composite and a layered inorganic filler. Among them, the core-shell structure A-B composite includes substance A and substance B. Specific substance A can build an efficient energy conduction and dissipation channel in the matrix resin network, and substance B, relying on its good elasticity and damping characteristics, undergoes large deformation under low-frequency vibration and consumes vibration energy. And an appropriate dosage of the core-shell structure A-B composite can better balance the various properties of the material, and using too much or too little will cause the material performance to deteriorate.

[0014] Furthermore, a layered inorganic filler is introduced. Its unique layered structure can interact with the matrix resin and other fillers, further enhancing the damping performance and material stability. In addition, the layered structure of the layered inorganic filler can also play a certain role in blocking rainwater and ultraviolet rays, improving the weather resistance and rain resistance of the material.

[0015] The vibration damping material provided by the present invention has a higher average loss factor at -20 - 80 °C, good comprehensive vibration damping effect, and can control Tg by regulating the dosage of the matrix resin monomer, making the service temperature of the material adapt to the usage scenario; at the same time, it has excellent salt spray resistance and waterproof performance, good weather resistance, can adapt to a variety of usage environments, and has high comprehensive application value.

[0016] Preferably, the isocyanate is at least one of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, polymethylene polyphenyl polyisocyanate;

[0017] and / or, the molecular weight of the polyether diol is 500 - 3000;

[0018] and / or, the molar ratio of -OH in the polyether diol to -NCO in the isocyanate is n(-OH):n(-NCO) = 1:(1 - 2).

[0019] The molar ratio of polyether diol to isocyanate in the monomer is one of the key factors affecting Tg. The hydroxyl group (-OH) of the polyether diol reacts with the isocyanate group (-NCO) to gradually form a hydroxyl-terminated polyurethane prepolymer. Increasing the content of the flexible chain segment of the polyether diol can endow the material with lower rigidity, thereby reducing Tg; conversely, if Tg is to be increased, the proportion of polyether diol is appropriately reduced. The molar ratio of polyether diol to isocyanate can be accurately regulated according to the required performance and the target glass transition temperature Tg.

[0020] Preferably, the molar ratio n(-OH):n(-NCO) of -OH in the polyether diol to -NCO in the isocyanate is one of 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2 or the range value of any two of them.

[0021] Preferably, the mass ratio of methyl methacrylate to isocyanate is (1 - 3):1;

[0022] and / or, the mass ratio of methyl methacrylate to butyl acrylate is (1 - 3):1.

[0023] The hydroxyl-terminated polyurethane prepolymer is further polymerized with acrylate monomers to form an interpenetrating network structure. At this time, the mass ratio of methyl methacrylate (MMA) to butyl acrylate (BA) plays a key role. MMA has a relatively high glass transition temperature, and increasing the proportion of MMA within a certain range will increase the Tg of the overall material; while BA has a relatively low glass transition temperature, increasing the proportion of BA will decrease the Tg. Similarly, according to the requirements for the Tg of the material, the mass ratio of MMA to BA can be precisely controlled to achieve regulation.

[0024] Preferably, the mass ratio of methyl methacrylate to butyl acrylate is one of 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, 3:1 or the range value of any two of them.

[0025] Preferably, the preparation method of the matrix resin emulsion is as follows:

[0026] (1) Mix polyether diol and isocyanate, add a catalyst, and react at 60 - 80 °C for 3 - 4 h to obtain a hydroxyl-terminated polyurethane prepolymer;

[0027] (2) Mix the hydroxyl-terminated polyurethane prepolymer, methyl methacrylate, and butyl acrylate, add an initiator and a crosslinking agent, and react at 60 - 70 °C for 5 - 6 h to obtain the modified polyurethane-acrylate interpenetrating network polymer;

[0028] (3) Under stirring at room temperature, add water and an emulsifier to the modified polyurethane-acrylate interpenetrating network polymer for emulsification to obtain the matrix resin emulsion.

[0029] During the reaction process, the hydroxyl group (-OH) of polyether diol and the isocyanate group (-NCO) first react under the action of a catalyst to gradually form a hydroxyl-terminated polyurethane prepolymer; then, under the action of an initiator and a crosslinking agent, MMA and BA monomers undergo a polymerization reaction, and at the same time, they penetrate and entangle with the hydroxyl-terminated polyurethane prepolymer to form a modified polyurethane-acrylate polymer with an interpenetrating network structure as the matrix resin, and a vibration damping material is further prepared after obtaining the matrix resin emulsion.

[0030] Further preferably, the catalyst is dibutyltin dilaurate, and the dosage of dibutyltin dilaurate is 0.2 - 0.5% of the total mass of polyether diol and isocyanate;

[0031] And / or, the initiator is at least one of benzoyl peroxide, tert-butyl hydroperoxide, methyl ethyl ketone peroxide, and azodiisobutyronitrile, and the dosage of the initiator is 0.5-2% of the mass of methyl methacrylate;

[0032] And / or, the crosslinking agent is at least one of pentaerythritol tetraacrylate, triallyl isocyanurate, vinyltrimethoxysilane, and trimethylolpropane triacrylate, and the dosage of the crosslinking agent is 0.5-3% of the mass of methyl methacrylate;

[0033] And / or, the emulsifier is sodium dodecyl sulfate, and the dosage of the sodium dodecyl sulfate is 1-2% of the mass of methyl methacrylate.

[0034] The crosslinking agent and the initiator also play an effect of comprehensive regulation. Appropriately adding the crosslinking agent will make the network structure more compact, thereby increasing Tg; while the change in the dosage of the initiator will affect the polymerization reaction rate and degree, indirectly affecting the network structure and Tg: increasing the initiator dosage and accelerating the polymerization reaction will result in a more compact network structure and an increase in Tg.

[0035] Preferably, the preparation method of the core-shell structure A-B composite is: dispersing substance A in water, adding an emulsifier and ultrasonic dispersing, then adding the emulsion of substance B and potassium persulfate, and reacting at 70-80°C for 6-8 h to obtain;

[0036] And / or, the mass ratio of substance A to substance B is 1:(2-5);

[0037] And / or, the particle size of the core-shell structure A-B composite is 80-250 nm;

[0038] And / or, the layered inorganic filler is at least one of nano-montmorillonite, organically modified vermiculite, and attapulgite;

[0039] And / or, the dosage of the layered inorganic filler accounts for 5-10% of the mass of the core-shell structure A-B composite.

[0040] Substance B is grafted onto the surface of substance A by in-situ emulsion polymerization and emulsified to obtain the core-shell structure A-B composite. Among them, the mass ratio of substance A to substance B has a great influence on the vibration damping effect of the vibration damping material of the present invention.

[0041] Preferably, the mass ratio of substance A to substance B is one of 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5 or the range value of any two of them.

[0042] As a preferred embodiment of the present invention, the emulsifier is sodium dodecyl sulfate, and the dosage of the emulsifier is 1-3% of the mass of the core-shell structure A-B composite; and / or, the dosage of potassium persulfate is 0.5-1% of the mass of the core-shell structure A-B composite.

[0043] Preferably, the raw materials for preparing the damping material further include a tackifier, a plasticizer and an auxiliary agent.

[0044] More preferably, the preparation method of the tackifier is: using alkylene oxide and organosiloxane as raw materials, reacting at 80-90 °C for 8-10 h under the catalysis of tetrabutylammonium bromide;

[0045] and / or, the plasticizer is at least one of tributyl acetylcitrate, dioctyl phthalate, dibutyl phthalate, epoxidized soybean oil;

[0046] and / or, the auxiliary agent includes a compound auxiliary agent and a light stabilizer, and the compound auxiliary agent is obtained by compounding an antioxidant and an ultraviolet absorber.

[0047] As a preferred embodiment of the present invention, the alkylene oxide is at least one of propylene oxide, ethylene oxide, epichlorohydrin, and the organosiloxane is at least one of vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane.

[0048] As a preferred embodiment of the present invention, the molar ratio of the alkylene oxide to the organosiloxane is (1-3):1.

[0049] As a preferred embodiment of the present invention, the dosage of tetrabutylammonium bromide is 0.5-2% of the mass of the alkylene oxide.

[0050] The present invention synthesizes a hybrid tackifier with epoxy groups and siloxane groups. Among them, the epoxy groups can chemically react with the active groups in the matrix resin to form chemical bonding; the siloxane groups have good adhesion and weather resistance, significantly improving the bonding strength between the damping film and various substrates, and still maintaining stable bonding performance in complex environments. The protective film formed by the siloxane groups on the material surface can not only enhance the bonding effect, but also effectively resist the erosion of ultraviolet rays, rainwater and oxygen, greatly improving the weather resistance and rain resistance of the material.

[0051] More preferably, the dosage of the tackifier is 5-10% of the mass of methyl methacrylate;

[0052] and / or, the dosage of the plasticizer is 2-5% of the mass of methyl methacrylate;

[0053] And / or, the dosage of the compounding auxiliary agent is 0.2-1% of the mass of methyl methacrylate, and the dosage of the light stabilizer is 0.3-0.8% of the mass of methyl methacrylate;

[0054] And / or, the mass ratio of the antioxidant to the ultraviolet absorber in the compounding auxiliary agent is (1-3):1.

[0055] Among them, the dosage of the plasticizer has a certain influence on the Tg of the matrix resin, and increasing its dosage can effectively reduce Tg.

[0056] As a preferred embodiment of the present invention, the antioxidant is at least one of antioxidant 168, antioxidant B215, and antioxidant 1076, and the ultraviolet absorber is at least one of UV-531, UV-9, and UV-571.

[0057] The antioxidant can effectively inhibit the oxidative degradation of the material during processing and use, and extend the service life of the material; the ultraviolet absorber can absorb ultraviolet rays, prevent the material from aging due to ultraviolet irradiation, and ensure the performance stability of the damping material in a light environment such as outdoors.

[0058] As a preferred embodiment of the present invention, the light stabilizer is at least one of light stabilizer 944, light stabilizer 622, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, and 2-hydroxy-4-methoxybenzophenone.

[0059] The light stabilizer can capture free radicals, effectively inhibit the photooxidation reaction, and cooperate with the antioxidant and the ultraviolet absorber to significantly improve the weather resistance of the material.

[0060] In a second aspect, the present invention provides a method for preparing the above-mentioned vibration damping material, which is characterized by including the following steps:

[0061] S1. While stirring, sequentially add the damping filler, tackifier, plasticizer, and auxiliary agent to the matrix resin emulsion, mix well, and then perform ultrasonic dispersion and high-shear dispersion treatment to obtain a mixed liquid;

[0062] S2. Cast the mixed liquid on a release film, dry and cure it, and then continue to cure it at room temperature to obtain the vibration damping material;

[0063] The drying and curing is carried out at 65-75°C for 1.2-1.8 h, and the curing time at room temperature is 30-40 h.

[0064] Preferably, in the step S1, the stirring speed is 900-1300 r / min;

[0065] And / or, the power of the ultrasonic wave is 350 - 550 W, the rotation speed of the high-shear dispersion is 2000 - 3000 r / min, and the treatment time is 30 - 40 min.

[0066] The ultrasonic disperser is used in combination with a high-speed shear disperser to perform synergistic treatment on the mixed liquid, ensuring that each additive is uniformly dispersed in the matrix resin to form a stable dispersion system, which helps to improve the overall weather resistance and rain resistance of the material. Drying and curing volatilize the solvent to form a damping film with a certain strength and flexibility. A sufficient drying and curing process can enhance the structural stability of the material and improve its resistance to environmental factors.

[0067] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0068] The present invention realizes precise regulation of the glass transition temperature Tg of the material by regulating the modified polyurethane-acrylate interpenetrating network polymer as the matrix resin, combined with the preparation of damping fillers, and the selection and ratio of specific tackifiers, plasticizers, and additives, so as to adapt to different usage requirements. The vibration damping material provided by the present invention has better comprehensive vibration damping performance in a wide temperature range, and also takes into account excellent weather resistance and rain resistance, and can be applied to different application environments, overcoming the problems existing in the existing vibration damping materials, and has high application value. Detailed implementation manners

[0069] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. The test methods used in the following embodiments are all conventional methods unless otherwise specified; the materials, reagents, etc. used are all reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0070] In the following embodiments and comparative examples, the sources of some materials and reagents are as follows:

[0071] Dibutyltin dilaurate: Shandong Qiyuan Chemical Industry Co., Ltd., industrial grade;

[0072] Methyl methacrylate: Jilin Petrochemical, content 99.9%;

[0073] Butyl acrylate: Shandong Chuangying Chemical Industry Co., Ltd., industrial grade;

[0074] Benzoyl peroxide: BPO, Jinan Shuangying Chemical Industry Co., Ltd., industrial grade;

[0075] Sodium dodecyl sulfate: Jiangsu Runfeng Synthetic Technology Co., Ltd.;

[0076] Multi-walled carbon nanotubes: Shenzhen Lithium You New Energy Technology Co., Ltd., model TOB-TNT-M, purity > 95wt%, inner diameter 3 - 5nm, outer diameter 8 - 15nm;

[0077] Nitrile latex: Wuhan Jiyesheng Chemical Co., Ltd., CAS No. 25265-19-4, acrylonitrile content 32 - 34%;

[0078] Nanometer montmorillonite: Zhejiang Fenghong New Materials Co., Ltd., model DK-7, particle size ≤ 20μm;

[0079] Crosslinking agent: Trimethylolpropane triacrylate, Jiangsu Runfeng Synthetic Technology Co., Ltd.;

[0080] Epichlorohydrin: Jiangsu Runfeng Synthetic Technology Co., Ltd.;

[0081] Vinyltrimethoxysilane: Jiangsu Runfeng Synthetic Technology Co., Ltd.;

[0082] Plasticizer: Tributyl acetylcitrate, Jiangsu Runfeng Synthetic Technology Co., Ltd.

[0083] Example 1

[0084] An example of the vibration damping material of the present invention. The preparation raw materials of the vibration damping material in this example include: matrix resin emulsion, damping filler, tackifier, plasticizer, and auxiliary agent. The formulation preparation is as follows:

[0085] Preparation of matrix resin emulsion:

[0086] (1) Preparation of hydroxyl-terminated polyurethane prepolymer

[0087] Raw material preparation: Select 210 polyether with a molecular weight of about 2000 and toluene diisocyanate (TDI-80). Weigh according to the mass ratio of polyether diol to TDI-80 of 8.2:1. At this time, n(-OH):n(-NCO) in polyether diol and TDI-80 = 1:1.4;

[0088] Reaction process: Add polyether diol to the reaction vessel, and slowly add TDI-80 under stirring. At the same time, add dibutyltin dilaurate accounting for 0.3% of the total mass of polyether diol and TDI-80 as a catalyst. Control the reaction temperature at 70°C and continue the reaction for 3.5h. The hydroxyl group (-OH) of polyether diol reacts with the isocyanate group (-NCO) of TDI-80 to gradually form a hydroxyl-terminated polyurethane prepolymer.

[0089] (2) Formation of a PU-IPN-PA with an interpenetrating network structure

[0090] Raw material addition and mixing: Transfer the prepared hydroxyl-terminated polyurethane prepolymer to another reaction vessel, add methyl methacrylate (MMA) and butyl acrylate (BA), such that the mass ratio of methyl methacrylate to toluene diisocyanate is 3:1, and control the mass ratio of MMA to BA to be 1.4:1. Then add benzoyl peroxide (BPO) as an initiator at 2% of the mass of methyl methacrylate, and trimethylolpropane triacrylate (TMPTA) as a crosslinking agent at 2% of the mass of methyl methacrylate;

[0091] Polymerization reaction: Control the temperature of the reaction system at 60 °C and carry out a free radical polymerization reaction for 6 h. Under the action of the initiator BPO, the MMA and BA monomers undergo a polymerization reaction, and at the same time penetrate and entangle with the hydroxyl-terminated polyurethane prepolymer to obtain a modified polyurethane-acrylate polymer (PU-IPN-PA) with an interpenetrating network structure; during the reaction process, the transparency and viscosity of the solution will change significantly, and the reaction process can be monitored by regularly sampling and testing.

[0092] (3) Preparation of the PU-IPN-PA matrix emulsion

[0093] Emulsification process: Cool the reaction product of step (2) to room temperature. Under stirring conditions, slowly add deionized water for emulsification, and add sodium dodecyl sulfate at 1% of the mass of methyl methacrylate as an emulsifier to help form a stable emulsion system. Continuously stir and control the stirring speed to ensure that the polymer is uniformly dispersed in water to form stable emulsion particles.

[0094] Post-treatment: After emulsification, filter the emulsion to remove possible unreacted impurities or agglomerated particles, improve the purity and stability of the emulsion, and obtain the matrix resin emulsion.

[0095] Preparation of damping filler:

[0096] Preparation of core-shell structured multi-walled carbon nanotube-nitrile rubber composite (MWCNT-NBR): Disperse multi-walled carbon nanotubes in deionized water, add sodium dodecyl sulfate as an emulsifier, and ultrasonically disperse for 35 min; then add nitrile rubber emulsion, and at the same time add potassium persulfate (KPS) as an initiator, and react at 75 °C for 7 h to obtain MWCNT-NBR; where the mass ratio of multi-walled carbon nanotubes to nitrile rubber is 1:2, the addition amount of the emulsifier is 2% of MWCNT-NBR, and the addition amount of the initiator is 0.5% of MWCNT-NBR;

[0097] The dosage of MWCNT-NBR is 15% of the mass of methyl methacrylate;

[0098] Nano-montmorillonite, with a dosage of 8% of the mass of MWCNT-NBR;

[0099] Preparation of tackifier:

[0100] Using epichlorohydrin and vinyltrimethoxysilane as raw materials, a tackifier of epoxy-silicone hybrid is prepared by reacting at 85 °C for 9 h under the catalysis of tetrabutylammonium bromide, wherein the molar ratio of epoxyalkane to siloxane is 2:1, and the dosage of tetrabutylammonium bromide is 1% of the mass of epoxyalkane;

[0101] The dosage of the tackifier is 8% of the mass of methyl methacrylate;

[0102] Plasticizer: tributyl acetylcitrate, and the dosage is 3% of the mass of methyl methacrylate;

[0103] Auxiliary agent:

[0104] A compound auxiliary agent is obtained by mixing antioxidant 168 and ultraviolet absorber UV-531. The total mass of the compound auxiliary agent is 0.5% of the mass of methyl methacrylate, and the mass ratio of antioxidant 168 to ultraviolet absorber UV-531 is 2:1;

[0105] Light stabilizer: bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, and the dosage is 0.5% of the mass of methyl methacrylate.

[0106] The preparation method of the damping material in this example is as follows:

[0107] S1. Add the PU-IPN-PA matrix resin emulsion into a high-speed stirrer, stir at a speed of 1000 r / min, and sequentially add MWCNT-NBR, nano-montmorillonite, epoxy-silicone hybrid tackifier, plasticizer tributyl acetylcitrate, compound auxiliary agent, and light stabilizer, and continue to stir for 50 min to preliminarily mix each component;

[0108] Then use an ultrasonic disperser combined with a high-speed shear disperser to perform synergistic treatment on the mixed solution. The ultrasonic power is 400 W, the high-speed shear rotation speed is 2000 r / min, and the treatment time is 30 min to ensure that each component is uniformly dispersed in the matrix resin.

[0109] S2. Uniformly cast the synergistically dispersed mixed solution onto a smooth polyethylene terephthalate (PET) release film through a high-precision casting machine, and then send the PET release film with the cast mixed solution into a hot air circulation drying oven and dry at 65 °C for 1.5 h; then place the dried film at room temperature for 36 h to further cure it to obtain the damping material.

[0110] Examples 2-7

[0111] Examples 2-7 are examples of the vibration damping material of the present invention. The differences between Examples 2-7 and Example 1 are only that the preparation raw materials are adjusted as follows:

[0112] In the preparation of the matrix resin emulsion in Example 2, the mass ratio of polyether diol to TDI-80 was adjusted to 6.4:1. At this time, n(-OH):n(-NCO)=1:1.8, and other dosage ratio conditions remained unchanged;

[0113] In the preparation of the matrix resin emulsion in Example 3, the mass ratio of polyether diol to TDI-80 was adjusted so that n(-OH):n(-NCO) in polyether diol and TDI-80 was 1:1.2, and other dosage ratio conditions remained unchanged;

[0114] In the preparation of the matrix resin emulsion in Example 4, the mass ratio of polyether diol to TDI-80 was adjusted so that n(-OH):n(-NCO) in polyether diol and TDI-80 was 1:0.8, and other dosage ratio conditions remained unchanged;

[0115] In the preparation of the matrix resin emulsion in Example 5, the mass ratio of MMA to BA was adjusted to 2:1, and other dosage ratio conditions remained unchanged;

[0116] In the preparation of the matrix resin emulsion in Example 6, the mass ratio of MMA to BA was adjusted to 2.5:1, and other dosage ratio conditions remained unchanged;

[0117] In the preparation of MWCNT-NBR in Example 7, the mass ratio of multi-walled carbon nanotubes to nitrile rubber was adjusted to 1:1, and other dosage ratio conditions remained unchanged;

[0118] The plasticizer tributyl acetyl citrate was removed from the preparation raw materials of Example 8.

[0119] The preparation method of the vibration damping materials in Examples 2-7 refers to Example 1.

[0120] Comparative Examples 1-3

[0121] The differences between the vibration damping materials in Comparative Examples 1-3 and Example 1 are only that the preparation raw materials are adjusted as follows:

[0122] In Comparative Example 1, the dosage of MWCNT-NBR was adjusted to 5% of the mass of methyl methacrylate;

[0123] In Comparative Example 2, the dosage of MWCNT-NBR was adjusted to 30% of the mass of methyl methacrylate;

[0124] The nano-montmorillonite was removed from the preparation raw materials of Comparative Example 3.

[0125] The preparation methods of the damping materials in Comparative Examples 1-3 refer to Example 1.

[0126] Effect Example

[0127] To explore the performance of the damping material of the present invention, the damping materials in the examples and comparative examples were tested as follows:

[0128] Vibration damping performance: Refer to GB / T 18258-2000 "Test Method for Damping Performance of Damping Materials";

[0129] Glass transition temperature: Refer to GB / T 40396-2021 "Test Method for Glass Transition Temperature of Polymer Matrix Composites - Dynamic Mechanical Analysis (DMA)";

[0130] Waterproof performance: Refer to GB / T 30693-2014 "Measurement of the Contact Angle of Plastic Films with Water";

[0131] Weather resistance: Refer to GB / T 10125-2012 "Artificial Atmosphere Corrosion Test - Salt Spray Test".

[0132] The above performance test results of the damping materials in the examples and comparative examples are shown in Table 1.

[0133] Table 1 Performance Test Results of the Damping Materials in the Examples and Comparative Examples

[0134]

[0135]

[0136] As can be seen from Table 1:

[0137] In contrast, the damping material provided by the present invention in the examples can better balance the performance: the average loss factor at -20 to 80 °C is above 0.18, and the vibration damping performance is better. The glass transition temperature Tg of the material in the examples is between -32 and (-55) °C. Among them, in Examples 3 and 4, by adjusting the molar ratio n(-OH):n(-NCO) of polyether diol and TDI-80 in the matrix resin monomer and decreasing the molar ratio of -NCO, the Tg is further reduced to above -40 °C. On the contrary, in Example 2, when the molar ratio of -NCO decreases, the Tg increases. At the same time, the damping materials in all examples can pass the 720-hour neutral salt spray test, and have good salt spray resistance; and the contact angle is above 122°, and the waterproof performance is good. The damping material provided by the present invention has better comprehensive vibration damping performance in a wide temperature range, and the Tg temperature is precisely controllable. It also takes into account excellent weather resistance and rainproof performance, and can be applied to different application environments.

[0138] It can be seen from the comparative examples and comparative examples 1, 2, and 3 that the specific amount of the core-shell structure AB composite in the damping filler and the added layered inorganic filler have a great influence on the performance of the vibration damping material of the present invention. In comparative example 1, the amount of MWCNT-NBR is reduced to 5% of the mass of methyl methacrylate, which is lower than the specified range, and the shock absorption performance, weather resistance and waterproofness of the material are significantly deteriorated, and the overall performance is reduced; while in comparative example 2, the amount of MWCNT-NBR is increased to 30% of the mass of methyl methacrylate, which is higher than the specified range. Excessive addition makes the vibration damping performance of the material significantly deteriorate, which may be related to the decrease in rebound performance. In comparative example 3, no layered inorganic filler nano-montmorillonite is added, and the shock absorption performance, weather resistance and waterproofness of the material are deteriorated.

[0139] In summary, the present invention mainly provides a vibration-damping damping material by optimizing the matrix resin and the damping filler. The glass transition temperature Tg of the material can be precisely controlled by adjusting the amount of each monomer in the preparation of the matrix resin, and combined with the selection and ratio of specific tackifiers, plasticizers, and additives, the comprehensive vibration-damping performance of the damping material in a wide temperature range is improved, while taking into account excellent weather resistance and rainproof performance. It can be applied to different application environments, overcomes the problems existing in existing vibration-damping damping materials, and has high application prospects.

[0140] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A vibration damping material, characterized in that, The raw materials for preparing the vibration damping material include a matrix resin emulsion and a damping filler; The matrix resin in the matrix resin emulsion is a modified polyurethane-acrylate interpenetrating network polymer, and the monomers of the modified polyurethane-acrylate interpenetrating network polymer include polyether diol, isocyanate, methyl methacrylate and butyl acrylate; The damping filler includes a core-shell structure A-B composite and a layered inorganic filler; in the core-shell structure A-B composite, substance A is at least one of multi-walled carbon nanotubes, graphene, carbon fiber, and nano-titanium dioxide, and substance B is at least one of nitrile rubber, styrene-butadiene rubber, chloroprene rubber, and carboxylated styrene-butadiene rubber; The dosage of the core-shell structure A-B composite is 10-20% of the mass of methyl methacrylate.

2. The vibration damping material according to claim 1, characterized in that, The isocyanate is at least one of toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and polymethylene polyphenyl polyisocyanate; And / or, the molecular weight of the polyether diol is 500-3000; And / or, the molar ratio of -OH in the polyether diol to -NCO in the isocyanate is n(-OH):n(-NCO)=1:(1-2).

3. The vibration damping material according to claim 1, wherein The mass ratio of methyl methacrylate to isocyanate is (1-3):1; And / or, the mass ratio of methyl methacrylate to butyl acrylate is (1-3):

1.

4. The vibration damping material according to any one of claims 1 to 3, characterized in that, The preparation method of the matrix resin emulsion is as follows: (1) Mix the polyether diol and the isocyanate, add a catalyst, and react at 60-80°C for 3-4 hours to obtain a hydroxyl-terminated polyurethane prepolymer; (2) Mix the hydroxyl-terminated polyurethane prepolymer, methyl methacrylate, and butyl acrylate, add an initiator and a crosslinking agent, and react at 60-70°C for 5-6 hours to obtain the modified polyurethane-acrylate interpenetrating network polymer; (3) Under stirring at room temperature, add water and an emulsifier to the modified polyurethane-acrylate interpenetrating network polymer for emulsification to obtain the matrix resin emulsion.

5. The vibration damping material according to claim 4, wherein, The catalyst is dibutyltin dilaurate, and the dosage of dibutyltin dilaurate is 0.2-0.5% of the total mass of the polyether diol and the isocyanate; And / or, the initiator is at least one of benzoyl peroxide, tert-butyl hydroperoxide, methyl ethyl ketone peroxide, and azobisisobutyronitrile, and the dosage of the initiator is 0.5-2% of the mass of methyl methacrylate; And / or, the crosslinking agent is at least one of pentaerythritol tetraacrylate, triallyl isocyanurate, vinyltrimethoxysilane, and trimethylolpropane triacrylate, and the dosage of the crosslinking agent is 0.5-3% of the mass of methyl methacrylate; And / or, the emulsifier is sodium dodecyl sulfate, and the dosage of sodium dodecyl sulfate is 1-2% of the mass of methyl methacrylate.

6. The vibration damping material according to claim 1, characterized in that, The preparation method of the core-shell structure A-B composite is: disperse substance A in water, add an emulsifier and disperse it by ultrasonic wave, then add the emulsion of substance B and potassium persulfate, and react at 70-80°C for 6-8 hours to obtain it; And / or, the mass ratio of substance A to substance B is 1:(2-5); And / or, the particle size of the core-shell structure A-B composite is 80-250 nm; And / or, the layered inorganic filler is at least one of nano-montmorillonite, organically modified vermiculite, and attapulgite; And / or, the dosage of the layered inorganic filler accounts for 5-10% of the mass of the core-shell structure A-B composite.

7. The vibration damping material according to claim 1, characterized in that, The raw materials for preparing the vibration damping material further include a tackifier, a plasticizer, and an auxiliary agent.

8. The vibration damping material according to claim 7, wherein The preparation method of the tackifier is: using alkylene oxide and organosiloxane as raw materials, reacting at 80-90 °C for 8-10 h under the catalysis of tetrabutylammonium bromide; And / or, the plasticizer is at least one of tributyl acetylcitrate, dioctyl phthalate, dibutyl phthalate, and epoxidized soybean oil; And / or, the auxiliary agent includes a compound auxiliary agent and a light stabilizer, and the compound auxiliary agent is obtained by compounding an antioxidant and an ultraviolet absorber.

9. The vibration damping material according to claim 8, wherein, The dosage of the tackifier is 5-10% of the mass of methyl methacrylate; And / or, the dosage of the plasticizer is 2-5% of the mass of methyl methacrylate; And / or, the dosage of the compound auxiliary agent is 0.2-1% of the mass of methyl methacrylate, and the dosage of the light stabilizer is 0.3-0.8% of the mass of methyl methacrylate; And / or, the mass ratio of the antioxidant to the ultraviolet absorber in the compound auxiliary agent is (1-3):

1.

10. The preparation method of the vibration damping material according to any one of claims 7-9, characterized in that Comprising the following steps: S1. Sequentially add a damping filler, a tackifier, a plasticizer, and an auxiliary agent to the matrix resin emulsion under stirring, mix well, and then perform ultrasonic dispersion and high-shear dispersion treatment to obtain a mixed solution; S2. Cast the mixed solution on a release film, dry and cure it, and then continue to cure it at room temperature to obtain the vibration damping material; The drying and curing is carried out at 65-75 °C for 1.2-1.8 h, and the curing time at room temperature is 30-40 h.

Images