Vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations and preparation method thereof

Abstract

The invention belongs to the technical field of polyurethane, and proposes a vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibration and a preparation method thereof, wherein the raw materials include a polyol component and an isocyanate component in a mass ratio of 100:70; the polyol component includes 50-70 parts of polyether polyol I, 20-30 parts of polyether polyol II, 5-8 parts of a chain extender, 0.2-0.5 parts of water, 0.2-0.5 parts of a modified boron nitride nanosheet, 1-1.5 parts of a foam stabilizer, and 0.4-0.6 parts of a catalyst; the isocyanate component is carbodiimide-modified MDI; the modified boron nitride nanosheet uses melamine and cyanuric acid to perform surface modification on the boron nitride nanosheet. In the present invention, the modified boron nitride nanosheet can be evenly dispersed in the polyurethane raw material, so that the composite nanosheet can also maintain a relatively uniform distribution state in the elastomer after casting and foaming.

Description

Technical Field

[0001] The invention belongs to the technical field of polyurethane and relates to a vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations. Background Art

[0002] During the operation of the urban rail train, certain vibrations will be generated, which will have a certain impact on the residential areas near the railway, and will also be detrimental to the protection of some ancient buildings near the running line. In the railway fastener system, the elastic pad can buffer the impact of the high-speed train on the roadbed and sleepers, and improve the smoothness of the train operation. Therefore, it is of great significance to prepare a polyurethane elastic pad that can filter and eliminate the low-frequency vibrations generated by the operation of the urban rail train.

[0003] In the prior art, the following technical means can be used to improve the vibration reduction and vibration isolation effect of polyurethane elastic pads: (1) Optimizing the molecular structure of polyurethane: By adjusting the raw material ratio and synthesis process of polyurethane, its molecular structure can be improved, thereby improving the vibration reduction and vibration isolation performance. For example, adjusting the type and ratio of polyether polyol and isocyanate, and adding an appropriate amount of chain extender, etc., can have a significant impact on the performance of polyurethane; (2) Introducing special functional groups: Introducing some special functional groups such as ester groups, ether groups, and carbamate groups during the synthesis of polyurethane can enhance the interaction between polyurethane molecules, thereby improving its damping performance and vibration reduction and vibration isolation effect; (3) Using blending modification: Blending and modifying polyurethane with other polymer materials can form a polymer composite material with excellent vibration reduction and vibration isolation performance. For example, blending polyurethane with rubber, plastic and other materials can combine the advantages of each component and improve the overall performance; (4) Introducing nanofillers such as one-dimensional nanofibers and two-dimensional nanosheets into the polyurethane network can improve the molecular network structure inside the original polyurethane elastomer and enhance the mechanical properties of the polyurethane elastomer. The introduction of nanofibers can enhance the interfacial interaction between nanofibers and polyurethane molecular networks, thereby improving the mechanical properties of polyurethane elastomers. The introduction of two-dimensional nanosheets can concentrate the stress between polyurethane networks in different regions, improve the efficiency of stress transfer, dissipate the energy of external stress to a greater extent, improve the mechanical properties of polyurethane elastomers, and then polyurethane elastomers can show good damping and vibration isolation effects for filtering low-frequency vibrations.

[0004] At the same time, different types of nanofillers (such as carbon nanotubes, graphene, silica, etc.) have different performance characteristics. Selecting suitable nanofillers can better improve the vibration reduction and isolation performance; however, the agglomeration and uneven distribution of nanofillers will directly affect the material performance. Therefore, based on the fact that the currently used polyurethane elastic pads are difficult to maintain excellent vibration reduction and isolation effects after a large number of impacts caused by train operation, it is urgent to provide a solution to improve the above problems. Summary of the invention

[0005] The present invention proposes a vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations and a preparation method thereof. The preparation method introduces modified boron nitride nanosheets surface-modified with melamine and cyanuric acid into a polyurethane elastomer. During the deformation of the polyurethane elastic pad under the action of an external force, the internal molecular network can achieve good stress concentration and stress transfer effects, and the entire elastomer exhibits good damping, vibration-damping and vibration-isolating performance for filtering low-frequency vibrations.

[0006] The technical solution of the present invention is achieved in this way:

[0007] A vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations, the raw materials of which include a polyol component and an isocyanate component in a mass ratio of 100:70;

[0008] The polyol component comprises 50-70 parts of polyether polyol I, 20-30 parts of polyether polyol II, 5-8 parts of chain extender, 0.2-0.5 parts of water, 0.2-0.5 parts of modified boron nitride nanosheets, 1-1.5 parts of foam stabilizer, and 0.4-0.6 parts of catalyst;

[0009] The polyether polyol I is a polyether polyol having a content of 36.2-57.5 mg KOH / g;

[0010] The polyether polyol II is a polyether polyol having a hydroxyl value of 34±1.5 mg KOH / g and a viscosity of 800-1000 mPa·s at 25°C;

[0011] The isocyanate component is carbodiimide-modified MDI;

[0012] The preparation method of the modified boron nitride nanosheets comprises the following steps: dispersing the boron nitride nanosheets in deionized water, forming a uniform suspension after ultrasonic dispersion, then adding melamine to the suspension, stirring at 75-85°C, continuously stirring until completely dissolved, adding a cyanuric acid aqueous solution, stirring at 70-100°C, filtering, washing and freeze-drying to obtain the modified boron nitride nanosheets; wherein the mass ratio of boron nitride: melamine: cyanuric acid is 0.7-1:1:1.

[0013] Preferably, the concentration of boron nitride nanosheets in the suspension is 2-6wt%;

[0014] The concentration of the cyanuric acid aqueous solution is 0.15 mol / L;

[0015] The ultrasonic power is 50-100 W, and the stirring speed is 300-500 rpm.

[0016] Preferably, the boron nitride nanosheet has a sheet diameter of 1-5 μm and a thickness of less than 5 nm;

[0017] The filtering step comprises: using a PTFE filter membrane with a pore size of 0.45 μm to perform vacuum filtration, maintaining the vacuum degree at -0.08 MPa;

[0018] The washing step comprises: washing 3-5 times with deionized water;

[0019] The freeze-drying steps include: pre-freezing temperature of -50°C for 12 hours; after pre-freezing, gradually heating to -20°C for 24 hours while maintaining the vacuum degree below 10Pa; and continuing drying for 48-72 hours.

[0020] Preferably, the polyether polyol I is PTMEG-1000 and / or PTMEG-3000; the polyether polyol II is selected from one or more of EP-330N, GEP-330N and LEP-330N.

[0021] Preferably, the chain extender is selected from one or more of 1,4-butanediol, ethylene glycol and 1,3-propylene glycol.

[0022] Preferably, the foam stabilizer is selected from one or more of AK-8804, AK-8803 and AK-8871.

[0023] Preferably, the catalyst is selected from one or more of an organotin catalyst, N-methylimidazole and A-1.

[0024] Preferably, the catalyst comprises 0.2 parts of stannous octoate, 0.2 parts of N-methylimidazole and 0.05 parts of A-1.

[0025] The preparation method of the above-mentioned vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations comprises the following steps:

[0026] Adding the modified boron nitride nanosheets to the polyol component and stirring under ultrasound, then adding each component to the polyol and stirring;

[0027] Subsequently, the polyol component and the isocyanate component are preheated separately, and then the two components are mixed, poured into the mold, and the mold is closed. Constant temperature aging is carried out at 70-100°C for 5-8 minutes. After the aging process is completed, the mold is opened to obtain the polyurethane elastic pad.

[0028] Preferably, the ultrasonic power is 50-100 W, the stirring rate is 300-500 rpm, and the stirring time is 15-40 min; and the preheating temperature is 40-60°C.

[0029] The working principle and beneficial effects of the present invention are:

[0030] 1. The present invention provides a method for preparing a polyurethane elastic pad that can filter low-frequency vibrations and has excellent damping, vibration reduction and vibration isolation functions. The surface of boron nitride (BN) nanosheets is modified by using melamine and cyanuric acid to prepare modified boron nitride nanosheets (BN@MCA composite nanosheets). The modified boron nitride nanosheets can be evenly dispersed in the polyurethane raw material, so that the composite nanosheets can also maintain a relatively uniform distribution state in the elastomer after casting and foaming.

[0031] The modified boron nitride nanosheets can form a strong interface interaction with the polyurethane molecular network. The polyurethane elastomer networks in different regions can achieve more efficient stress concentration and stress transfer through the modified boron nitride nanosheets, and thus can dissipate external stress to a greater extent. The prepared polyurethane elastic pad can exhibit excellent mechanical properties, can effectively filter low-frequency vibrations, and ultimately show excellent practical application effects of damping, vibration reduction and vibration isolation.

[0032] The present invention also adopts a specific polyether polyol and isocyanate mixed reaction to improve the mechanical properties and damping vibration isolation properties of the polyurethane elastic pad; when other types of polyether polyols and isocyanates are used for mixed reaction, the mechanical properties and damping vibration isolation properties of the prepared polyurethane elastic pad will be reduced.

[0033] 2. In the pouring and maturing process of the present invention, isocyanate in the polyurethane raw material reacts with water to generate CO2, thereby generating a cellular structure in the elastomer. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0035] Figure 1 This is the X-ray diffraction pattern of the modified boron nitride nanosheets prepared in Example 1 of the present invention;

[0036] In the figure, BN@MCA represents the modified boron nitride nanosheets prepared in Example 1, and BN represents the boron nitride nanosheets. DETAILED DESCRIPTION

[0037] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Unless otherwise specified, the equipment used in this embodiment is conventional equipment, the reagents used are conventional reagents, all of which can be commercially obtained, and the operating methods used are all recorded in textbooks in this field.

[0039] In the following examples and comparative examples, PTMEG-1000 and PTMEG-3000 used were purchased from BASF;

[0040] EP330N was purchased from Bluestar Dongda Co., Ltd.;

[0041] GEP-330N was purchased from Shanghai Gaoqiao Petrochemical;

[0042] LEP-330N was purchased from Shandong Longhua New Materials Co., Ltd.;

[0043] AK-8804, AK-8803, and AK-8871 were purchased from Jiangsu Meside Chemical Co., Ltd.;

[0044] Carbodiimide-modified MDI was purchased from Wanhua Chemical Group Co., Ltd. as CDMDI-100L;

[0045] The boron nitride nanosheet has a sheet diameter of 1-5 μm and a thickness of less than 5 nm;

[0046] The concentration of the cyanuric acid aqueous solution used in the following examples and comparative examples is 0.15 mol / L.

[0047] Example 1

[0048] A method for preparing a vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations comprises the following steps:

[0049] A. Preparation

[0050] Prepare raw materials: polyol component and isocyanate component in a mass ratio of 100:70;

[0051] The polyol component includes 65 parts of PTMEG-1000, 25 parts of GEP-330N, 7 parts of 1,4-butanediol, 0.5 parts of water, 0.2 parts of modified boron nitride nanosheets, 1.2 parts of AK-8804, and 0.5 parts of a catalyst;

[0052] The isocyanate component is carbodiimide-modified MDI;

[0053] The catalyst includes 0.2 parts of stannous octoate, 0.2 parts of N-methylimidazole and 0.05 parts of A-1;

[0054] The preparation method of the modified boron nitride nanosheets comprises the following steps: dispersing the boron nitride nanosheets in deionized water, and performing ultrasonic dispersion at 60W for 25 minutes to form a uniform suspension, wherein the boron nitride nanosheets in the suspension account for 4wt%, and then adding melamine to the suspension, stirring at 80°C with a stirring rate of 500rpm, and continuously stirring until the suspension is completely dissolved and no visible solid particles are formed in the suspension, and then adding cyanuric acid aqueous solution, stirring at 95°C with a stirring rate of 500rpm and a stirring time of 30 minutes, filtering, The modified boron nitride nanosheets can be obtained by washing and freeze drying; wherein the mass ratio of boron nitride: melamine: cyanuric acid is 0.8:1:1; wherein the filtration is performed by vacuum filtration using a PTFE filter membrane with a pore size of 0.45 μm, and the vacuum degree is maintained at -0.08 MPa; the washing is performed 4 times using deionized water; the freeze drying comprises: the pre-freezing temperature is -50°C, and the pre-freezing time is 12 hours; after the pre-freezing is completed, the temperature is gradually raised to -20°C, and maintained for 24 hours, while the vacuum degree is maintained below 10 Pa; and the drying is continued for 48 hours;

[0055] B. Add the modified boron nitride nanosheets to the polyol component, stir for 30 min under 80W ultrasound at a stirring rate of 500 rpm, then add each component to the polyol, stir for 30 min at a stirring rate of 500 rpm, and evenly mix and disperse each component of the polyol;

[0056] C. Then preheat the polyol component and the isocyanate component to 50°C respectively, mix the two components, pour them into the mold, close the mold, and perform constant temperature aging at 100°C for 7 minutes. After the aging process is completed, open the mold to obtain the polyurethane elastic pad.

[0057] Example 2

[0058] A method for preparing a vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations comprises the following steps:

[0059] A. Preparation

[0060] Prepare raw materials: polyol component and isocyanate component in a mass ratio of 100:70;

[0061] The polyol component includes 50 parts of PTMEG-3000, 30 parts of EP-330N, 2 parts of ethylene glycol, 3 parts of 1,3-propylene glycol, 0.2 parts of water, 0.5 parts of modified boron nitride nanosheets, 0.5 parts of AK-8871, 0.5 parts of AK-8803, and 0.6 parts of a catalyst;

[0062] The isocyanate component is carbodiimide-modified MDI;

[0063] The catalyst includes 0.2 parts of stannous octoate, 0.2 parts of N-methylimidazole and 0.05 parts of A-1;

[0064] The preparation method of the modified boron nitride nanosheets comprises the following steps: dispersing the boron nitride nanosheets in deionized water, and performing 50W ultrasonic dispersion for 30 minutes to form a uniform suspension, wherein the boron nitride nanosheets in the suspension account for 2 wt %, and then adding melamine to the suspension, stirring at 85°C, at a stirring rate of 300 rpm, and continuously stirring until the suspension is completely dissolved and no visible solid particles are formed in the suspension, and then adding cyanuric acid aqueous solution, stirring at 100°C, at a stirring rate of 300 rpm, and for 40 minutes, and filtering. , washing and freeze drying, the modified boron nitride nanosheets can be obtained; wherein the mass ratio of boron nitride: melamine: cyanuric acid is 0.7:1:1; wherein the filtration is performed using a PTFE filter membrane with a pore size of 0.45 μm for vacuum filtration, and the vacuum degree is maintained at -0.08 MPa; washing is performed 5 times with deionized water; freeze drying includes: pre-freezing temperature of -50°C, pre-freezing time of 12 hours; after the pre-freezing is completed, the temperature is gradually raised to -20°C, maintained for 24 hours, while maintaining the vacuum degree below 10 Pa; drying is continued for 48 hours;

[0065] B. Add the modified boron nitride nanosheets to the polyol component, stir under 100W ultrasound for 15 minutes at a stirring rate of 300 rpm, then add each component to the polyol, stir for 15 minutes at a stirring rate of 300 rpm, and evenly mix and disperse each component of the polyol;

[0066] C. Then preheat the polyol component and the isocyanate component to 40°C respectively, mix the two components and pour them into the mold, close the mold, and perform constant temperature aging at 70°C for 8 minutes. After the aging process is completed, open the mold to obtain the polyurethane elastic pad.

[0067] Example 3

[0068] A method for preparing a vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations comprises the following steps:

[0069] A. Preparation

[0070] Prepare raw materials: polyol component and isocyanate component in a mass ratio of 100:70;

[0071] The polyol component includes 70 parts of PTMEG-1000, 20 parts of LEP-330N, 8 parts of 1,4-butanediol, 0.4 parts of water, 0.4 parts of modified boron nitride nanosheets, 1.5 parts of AK-8804, and 0.4 parts of a catalyst;

[0072] The isocyanate component is carbodiimide-modified MDI;

[0073] The catalyst includes 0.2 parts of stannous octoate, 0.2 parts of N-methylimidazole and 0.05 parts of A-1;

[0074] The preparation method of the modified boron nitride nanosheets comprises the following steps: dispersing the boron nitride nanosheets in deionized water, and forming a uniform suspension after 100W ultrasonic dispersion for 20 minutes, wherein the boron nitride nanosheets in the suspension account for 6wt%, then adding melamine to the suspension, stirring at 80°C, stirring at a rate of 400rpm, and continuously stirring until it is completely dissolved and no visible solid particles are formed in the suspension, and then adding cyanuric acid aqueous solution, stirring at 70°C, stirring at a rate of 400rpm, and stirring for 20 minutes, and then stirring at 70°C, stirring at a rate of 400rpm, and stirring for 20 minutes. Filtration, washing and freeze drying can obtain modified boron nitride nanosheets; wherein the mass ratio of boron nitride: melamine: cyanuric acid is 1:1:1; wherein the filtration is performed using a PTFE filter membrane with a pore size of 0.45 μm for vacuum filtration, and the vacuum degree is maintained at -0.08 MPa; washing is performed 3 times using deionized water; freeze drying includes: pre-freezing temperature of -50°C and pre-freezing time of 12 hours; after pre-freezing, gradually heating to -20°C and maintaining for 24 hours, while maintaining the vacuum degree below 10 Pa; and drying is continued for 72 hours;

[0075] B. Add the modified boron nitride nanosheets to the polyol component, stir under 50W ultrasound for 40 minutes at a stirring rate of 400 rpm, then add each component to the polyol, stir for 40 minutes at a stirring rate of 400 rpm, and evenly mix and disperse each component of the polyol;

[0076] C. Then preheat the polyol component and isocyanate component to 40-60°C respectively, mix the two components and pour them into the mold, close the mold, and perform constant temperature aging at 90°C for 5 minutes. After the aging process is completed, open the mold to obtain the final BN@MCA / CPU polyurethane elastomer.

[0077] Example 4

[0078] A method for preparing a vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations comprises the following steps:

[0079] A. Preparation

[0080] Prepare raw materials: polyol component and isocyanate component in a mass ratio of 100:70;

[0081] The polyol component includes 65 parts of PTMEG-1000, 25 parts of GEP-330N, 7 parts of 1,4-butanediol, 0.5 parts of water, 0.2 parts of modified boron nitride nanosheets, 1.2 parts of AK-8804, and 0.5 parts of a catalyst;

[0082] The isocyanate component is carbodiimide-modified MDI;

[0083] The catalyst includes 0.2 parts of stannous octoate, 0.2 parts of N-methylimidazole and 0.05 parts of A-1;

[0084] The preparation method of the modified boron nitride nanosheets comprises the following steps: dispersing the boron nitride nanosheets in deionized water, and performing ultrasonic dispersion at 60W for 20 minutes to form a uniform suspension, wherein the boron nitride nanosheets in the suspension account for 3wt%, and then adding melamine to the suspension, stirring at 75°C with a stirring rate of 500rpm, and continuously stirring until the suspension is completely dissolved and no visible solid particles are formed in the suspension, and then adding cyanuric acid aqueous solution, stirring at 75°C with a stirring rate of 500rpm and a stirring time of 20 minutes, filtering, The modified boron nitride nanosheets can be obtained by washing and freeze drying; wherein the mass ratio of boron nitride: melamine: cyanuric acid is 0.8:1:1; wherein the filtration is performed by vacuum filtration using a PTFE filter membrane with a pore size of 0.45 μm, and the vacuum degree is maintained at -0.08 MPa; washing is performed 3 times using deionized water; freeze drying includes: pre-freezing temperature of -50°C and pre-freezing time of 12 hours; after the pre-freezing is completed, the temperature is gradually raised to -20°C and maintained for 24 hours, while maintaining the vacuum degree below 10 Pa; and drying is continued for 48 hours;

[0085] B. Add the modified boron nitride nanosheets to the polyol component, stir under 60W ultrasound for 25 minutes at a stirring rate of 500 rpm, then add each component to the polyol, stir for 25 minutes at a stirring rate of 500 rpm, and evenly mix and disperse each component of the polyol;

[0086] C. Then preheat the polyol component and the isocyanate component to 50°C respectively, mix the two components, pour them into the mold, close the mold, and perform constant temperature aging at 100°C for 7 minutes. After the aging process is completed, open the mold to obtain the polyurethane elastic pad.

[0087] Comparative Example 1

[0088] A method for preparing a vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations comprises the following steps:

[0089] A. Preparation

[0090] Prepare raw materials: polyol component and isocyanate component in a mass ratio of 100:70;

[0091] The polyol component includes 65 parts of PTMEG-1000, 25 parts of GEP-330N, 7 parts of 1,4-butanediol, 0.5 parts of water, 0.2 parts of melamine and cyanuric acid complex MCA, 1.2 parts of AK-8804, and 0.5 parts of catalyst;

[0092] The isocyanate component is carbodiimide-modified MDI;

[0093] The catalyst includes 0.2 parts of stannous octoate, 0.2 parts of N-methylimidazole and 0.05 parts of A-1;

[0094] The preparation method of the melamine and cyanuric acid complex MCA comprises the following steps: dissolving melamine in deionized water, stirring continuously at 80°C until completely dissolved, with a stirring rate of 500rpm, then adding a cyanuric acid aqueous solution, stirring at 95°C, with a stirring rate of 500rpm, and stirring for 30min, filtering, washing and freeze-drying to obtain the melamine and cyanuric acid MCA complex; wherein the mass ratio of melamine to cyanuric acid is 1:1; filtration is performed using a PTFE filter membrane with a pore size of 0.45μm for vacuum filtration, and the vacuum degree is maintained at -0.08MPa; washing is performed 4 times using deionized water; freeze-drying comprises: a pre-freezing temperature of -50°C and a pre-freezing time of 12 hours; after the pre-freezing is completed, gradually heating to -20°C and maintaining for 24 hours, while maintaining the vacuum degree below 10Pa; and continuing drying for 48 hours;

[0095] B. Add melamine and cyanuric acid MCA complex to the polyol component, stir for 30 min under 80W ultrasound at a stirring rate of 500 rpm, then add each component to the polyol, stir for 30 min at a stirring rate of 500 rpm, and evenly mix and disperse each component of the polyol;

[0096] C. Then preheat the polyol component and the isocyanate component to 50°C respectively, mix the two components, pour them into the mold, close the mold, and perform constant temperature aging at 100°C for 7 minutes. After the aging process is completed, open the mold to obtain the polyurethane elastic pad.

[0097] Comparative Example 2

[0098] A method for preparing a vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations comprises the following steps:

[0099] A. Preparation

[0100] Prepare raw materials: polyol component and isocyanate component in a mass ratio of 100:70;

[0101] The polyol component includes 65 parts of PTMEG-1000, 25 parts of GEP-330N, 7 parts of 1,4-butanediol, 0.5 parts of water, 0.2 parts of boron nitride nanosheets, 1.2 parts of AK-8804, and 0.5 parts of a catalyst;

[0102] The isocyanate component is carbodiimide-modified MDI;

[0103] The catalyst includes 0.2 parts of stannous octoate, 0.2 parts of N-methylimidazole and 0.05 parts of A-1;

[0104] B. Adding boron nitride nanosheets to the polyol component, stirring for 30 min under 80W ultrasound at a stirring rate of 500 rpm, then adding each component to the polyol, stirring for 30 min at a stirring rate of 500 rpm, and uniformly mixing and dispersing each component of the polyol;

[0105] C. Then preheat the polyol component and the isocyanate component to 50°C respectively, mix the two components, pour them into the mold, close the mold, and perform constant temperature aging at 100°C for 7 minutes. After the aging process is completed, open the mold to obtain the polyurethane elastic pad.

[0106] Comparative Example 3

[0107] A method for preparing a vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations comprises the following steps:

[0108] A. Preparation

[0109] Prepare raw materials: polyol component and isocyanate component in a mass ratio of 100:70;

[0110] The polyol component includes 65 parts of PTMEG-1000, 25 parts of GEP-330N, 7 parts of 1,4-butanediol, 0.5 parts of water, 1.2 parts of AK-8804, and 0.5 parts of catalyst;

[0111] The isocyanate component is carbodiimide-modified MDI;

[0112] The catalyst includes 0.2 parts of stannous octoate, 0.2 parts of N-methylimidazole and 0.05 parts of A-1;

[0113] B. Add each component to the polyol, stir for 30 minutes at a stirring rate of 500 rpm to uniformly mix and disperse each component of the polyol;

[0114] C. Then preheat the polyol component and the isocyanate component to 50°C respectively, mix the two components, pour them into the mold, close the mold, and perform constant temperature aging at 100°C for 7 minutes. After the aging process is completed, open the mold to obtain the polyurethane elastic pad.

[0115] Comparative Example 4

[0116] A method for preparing a vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations comprises the following steps:

[0117] A. Preparation

[0118] Prepare raw materials: polyol component and isocyanate component in a mass ratio of 100:70;

[0119] The polyol component includes 65 parts of PTMEG-1000, 25 parts of GEP-330N, 7 parts of 1,4-butanediol, 0.5 parts of water, 0.2 parts of modified boron nitride nanosheets, 1.2 parts of AK-8804, and 0.5 parts of a catalyst;

[0120] The isocyanate component is carbodiimide-modified MDI;

[0121] The catalyst includes 0.2 parts of stannous octoate, 0.2 parts of N-methylimidazole and 0.05 parts of A-1;

[0122] The preparation method of the modified boron nitride nanosheets comprises the following steps: dispersing the boron nitride nanosheets in deionized water, and then performing ultrasonic dispersion at 60W for 25 minutes to form a uniform suspension, wherein the boron nitride nanosheets in the suspension account for 4wt%, and then adding melamine to the suspension, stirring at 80°C, with a stirring rate of 500rpm, and continuously stirring until the suspension is completely dissolved, and no visible solid particles are formed in the suspension, and then filtering, washing and freeze-drying to obtain the modified boron nitride nanosheets; wherein the mass ratio of boron nitride to melamine is 0.8:1; wherein the filtration is performed by vacuum filtration using a PTFE filter membrane with a pore size of 0.45μm, and the vacuum degree is maintained at -0.08MPa; washing is performed 4 times using deionized water; freeze-drying comprises: a pre-freezing temperature of -50°C and a pre-freezing time of 12 hours; after the pre-freezing is completed, gradually heating to -20°C and maintaining for 24 hours, while maintaining the vacuum degree below 10Pa; and continuing drying for 48 hours;

[0123] B. Add the modified boron nitride nanosheets to the polyol component, stir for 30 min under 80W ultrasound at a stirring rate of 500 rpm, then add each component to the polyol, stir for 30 min at a stirring rate of 500 rpm, and evenly mix and disperse each component of the polyol;

[0124] C. Then preheat the polyol component and the isocyanate component to 50°C respectively, mix the two components, pour them into the mold, close the mold, and perform constant temperature aging at 100°C for 7 minutes. After the aging process is completed, open the mold to obtain the polyurethane elastic pad.

[0125] Comparative Example 5

[0126] A method for preparing a vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations comprises the following steps:

[0127] A. Preparation

[0128] Prepare raw materials: polyol component and isocyanate component in a mass ratio of 100:70;

[0129] The polyol component includes 65 parts of PTMEG-1000, 25 parts of GEP-330N, 7 parts of 1,4-butanediol, 0.5 parts of water, 0.2 parts of modified boron nitride nanosheets, 1.2 parts of AK-8804, and 0.5 parts of a catalyst;

[0130] The isocyanate component is carbodiimide-modified MDI;

[0131] The catalyst includes 0.2 parts of stannous octoate, 0.2 parts of N-methylimidazole and 0.05 parts of A-1;

[0132] The preparation method of the modified boron nitride nanosheets comprises the following steps: dispersing the boron nitride nanosheets in deionized water, and performing ultrasonic dispersion at 60W for 25 minutes to form a uniform suspension, wherein the boron nitride nanosheets in the suspension account for 4wt%, and then adding cyanuric acid to the suspension, stirring at 95°C, with a stirring rate of 500rpm and a stirring time of 30 minutes, filtering, washing and freeze-drying to obtain the modified boron nitride nanosheets; wherein the mass ratio of boron nitride to cyanuric acid is 0.8:1; wherein the filtration is performed by vacuum filtration using a PTFE filter membrane with a pore size of 0.45μm, and the vacuum degree is maintained at -0.08MPa; washing is performed 4 times using deionized water; freeze-drying comprises: a pre-freezing temperature of -50°C and a pre-freezing time of 12 hours; after the pre-freezing is completed, gradually heating to -20°C and maintaining for 24 hours, while maintaining the vacuum degree below 10Pa; and continuing drying for 48 hours;

[0133] B. Add cyanuric acid-modified boron nitride nanosheets to the polyol component, stir under 80W ultrasound for 30 minutes at a stirring rate of 500 rpm, then add each component to the polyol, stir for 30 minutes at a stirring rate of 500 rpm, and evenly mix and disperse each component of the polyol;

[0134] C. Then preheat the polyol component and the isocyanate component to 50°C respectively, mix the two components, pour them into the mold, close the mold, and perform constant temperature aging at 100°C for 7 minutes. After the aging process is completed, open the mold to obtain the polyurethane elastic pad.

[0135] Performance Test:

[0136] According to the corresponding standards, various performance tests were performed on the polyurethane elastic pads prepared in Examples 1 to 4 and the products prepared in Comparative Examples 1 to 5. The test results are shown in Table 1.

[0137] Among them, the compression permanent deformation test refers to the standard GB / T 10653, the tensile strength and elongation at break test refers to the standard GB / T 10654; the dynamic-static stiffness ratio test refers to the standard TB / T 3395.1-2015.

[0138] Table 1

[0139]

[0140] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations, characterized in that: The raw materials include a polyol component and an isocyanate component in a mass ratio of 100:70; The polyol component comprises 50-70 parts of polyether polyol I, 20-30 parts of polyether polyol II, 5-8 parts of chain extender, 0.2-0.5 parts of water, 0.2-0.5 parts of modified boron nitride nanosheets, 1-1.5 parts of foam stabilizer, and 0.4-0.6 parts of catalyst; The polyether polyol I is a polyether polyol having a hydroxyl value of 36.2-57.5 mg KOH / g; The polyether polyol II is a polyether polyol having a hydroxyl value of 34±1.5 mg KOH / g and a viscosity of 800-1000 mPa·s at 25°C; The isocyanate component is carbodiimide-modified MDI; The preparation method of the modified boron nitride nanosheets comprises the following steps: dispersing the boron nitride nanosheets in deionized water, forming a uniform suspension after ultrasonic dispersion, then adding melamine to the suspension, stirring at 75-85°C, continuously stirring until completely dissolved, adding a cyanuric acid aqueous solution, stirring at 70-100°C, filtering, washing and freeze-drying to obtain the modified boron nitride nanosheets; wherein the mass ratio of boron nitride: melamine: cyanuric acid is 0.7-1:1:

1.

2. The vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations according to claim 1, characterized in that: The concentration of boron nitride nanosheets in the suspension is 2-6wt%; The concentration of the cyanuric acid aqueous solution is 0.15 mol / L; The ultrasonic power is 50-100 W, and the stirring speed is 300-500 rpm.

3. The vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations according to claim 1, characterized in that: The boron nitride nanosheet has a sheet diameter of 1-5 μm and a thickness of less than 5 nm; The filtering step comprises: using a PTFE filter membrane with a pore size of 0.45 μm to perform vacuum filtration, maintaining the vacuum degree at -0.08 MPa; The washing step comprises: washing 3-5 times with deionized water; The freeze-drying steps include: pre-freezing temperature of -50°C for 12 hours; after pre-freezing, gradually heating to -20°C for 24 hours while maintaining the vacuum degree below 10Pa; and continuing drying for 48-72 hours.

4. The vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations according to claim 1, characterized in that: The polyether polyol I is PTMEG-1000 and / or PTMEG-3000; the polyether polyol II is selected from one or more of EP-330N, GEP-330N and LEP-330N.

5. The vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations according to claim 1, characterized in that: The chain extender is selected from one or more of 1,4-butanediol, ethylene glycol and 1,3-propylene glycol.

6. The vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations according to claim 1, characterized in that: The foam stabilizer is selected from one or more of AK-8804, AK-8803 and AK-8871.

7. The vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations according to claim 1, characterized in that: The catalyst is selected from one or more of an organic tin catalyst, N-methylimidazole and A-1.

8. The vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations according to claim 1, characterized in that: The catalyst includes 0.2 parts of stannous octoate, 0.2 parts of N-methylimidazole and 0.05 parts of A-1.

9. A method for preparing a vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibrations as claimed in claim 1, characterized in that: The following steps are involved: Adding the modified boron nitride nanosheets to the polyol component and stirring under ultrasound, then adding each component to the polyol and stirring; Subsequently, the polyol component and the isocyanate component are preheated separately, and then the two components are mixed, poured into the mold, and the mold is closed. Constant temperature aging is carried out at 70-100°C for 5-8 minutes. After the aging process is completed, the mold is opened to obtain the polyurethane elastic pad.

10. The method for preparing the vibration-damping and vibration-isolating polyurethane elastic pad capable of filtering low-frequency vibration according to claim 9, characterized in that: The ultrasonic power is 50-100W, the stirring rate is 300-500rpm, and the stirring time is 15-40min; the preheating temperature is 40-60°C.

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