A microcellular polyurethane acoustic insulation mat and method of making the same

Abstract

The present application provides a kind of microporous polyurethane sound insulation pad and its preparation method, the microporous polyurethane sound insulation pad includes microporous polyurethane core layer (10), two fireproof fiber cloth layers (20) are arranged on the upper and lower surfaces of microporous polyurethane core layer (10).The polyurethane elastomer of the present application has higher compressive strength, good compression and creep resistance, excellent hydrolysis resistance and lower water absorption;And the sound insulation pad as a whole has good fireproof and sound insulation performance.

Description

Technical Field

[0001] This invention relates to the field of vibration control technology, and in particular to a microporous polyurethane sound insulation pad and its preparation method. Background Technology

[0002] Currently, most residential building floors in my country are constructed with reinforced concrete slabs and plastered surfaces. Concrete slabs are relatively rigid and cannot effectively isolate impact noise. Impact noise from reinforced concrete slabs can typically exceed 80 dB, surpassing the impact noise levels required by standards such as GB 50118-2010 "Code for Sound Insulation Design of Civil Buildings" and GB 50118-2011 "Code for Design of Residential Buildings". A common noise reduction method in my country involves laying an elastic pad on the reinforced concrete slab, followed by concrete or cement mortar. This method effectively isolates impact noise. Floating floor slabs are a technically mature and effective solution with reasonable costs, making them a feasible option for addressing noise and impact noise interference. Commonly used materials for floating floor slab sound insulation pads include rubber, polystyrene, and glass wool, all of which have already been applied in engineering projects.

[0003] However, existing rubber sound insulation pads are mostly made from waste rubber granules laminated with adhesives, resulting in poor fire resistance and easy aging and hardening. Sound insulation pads made of foamed polyethylene, styrene, etc., have low compressive strength and are prone to creep, which may cause cracking of the surface concrete under uneven loads. Glass wool sound insulation pads have low compressive strength and their sound insulation effect decreases after absorbing water. Microporous polyurethane is an ideal vibration damping and noise reduction material, but existing microporous polyurethane pads have poor flame retardant properties, posing a fire hazard during preparation, production, and use when directly used as sound insulation pads for floating floors. Therefore, a microporous polyurethane vibration damping pad with high compressive strength, low compressive creep, low water absorption, high flame retardant rating, and good sound insulation effect is needed to meet market demand. Summary of the Invention

[0004] To address at least one problem in the existing technology, the invention proposes a microporous polyurethane sound insulation pad and its preparation method. The polyurethane elastomer has high compressive strength, good resistance to compression and creep, excellent resistance to hydrolysis, and low water absorption. Furthermore, the sound insulation pad as a whole has good fire resistance and sound insulation properties.

[0005] According to one aspect of the present invention, a microporous polyurethane sound insulation pad is provided, comprising: a microporous polyurethane core layer (10) and two fireproof fiber cloth layers (20) disposed on the upper and lower surfaces of the microporous polyurethane core layer (10).

[0006] According to an embodiment of the present invention, the thickness of the microporous polyurethane core layer (10) is 1 to 24 mm, and the thickness of each fireproof fiber cloth layer (20) is 0.5 to 2 mm.

[0007] According to an embodiment of the present invention, the polyurethane elastomer of the microporous polyurethane core layer (10) is open-cell or closed-cell, with an average pore size of 0.05-0.5 mm and a density of 150-400 kg / mm³. 3 .

[0008] According to an embodiment of the present invention, the fireproof fiber cloth layer (20) is made of a material selected from glass fiber cloth, carbon fiber cloth, basalt fiber cloth, and ceramic fiber cloth.

[0009] According to an embodiment of the present invention, the impact sound pressure level improvement of the microporous polyurethane sound insulation pad is not less than 30 dB.

[0010] According to an embodiment of the present invention, the microporous polyurethane sound insulation pad achieves a combustion performance rating of B1.

[0011] According to an embodiment of the present invention, the microporous polyurethane is prepared by the following method:

[0012] The preparation of component A involves reacting 50-80 parts by weight of polyoxypropylene glycol (preferably PPG1000), 1-3 parts by weight of castor oil, 40-60 parts by weight of polytetrahydrofuran glycol, 22-30 parts by weight of expanded graphite, and 4-8 parts by weight of hollow glass microspheres to prepare component A.

[0013] The preparation of component B includes reacting 170-280 parts by weight of modified MDI (MM103C) and 80-100 parts by weight of polyoxypropylene glycol (preferably PPG2000) to prepare component B; and

[0014] Component A, heated to 40-50℃, and component B, heated to 50-60℃, are mixed together and reacted for 20-30 minutes to obtain a microporous polyurethane elastomer. The molar ratio of -NCO groups in component B to -OH groups in component A is 1-1.03.

[0015] According to an embodiment of the present invention, the step of preparing component A further includes adding about 5 to 8 parts by weight of flame retardant.

[0016] According to an embodiment of the present invention, the step of preparing component A further includes adding appropriate amounts of 2-5 parts by weight of chain extender, 1.5-3 parts by weight of crosslinking agent, 0.5-1.2 parts by weight of water, 0.1-0.3 parts by weight of catalyst, 0.5-1 parts by weight of foam stabilizer, 1.5-2 parts by weight of cell opener, 0.1-0.3 parts by weight of water repellent and 0.8-1.5 parts by weight of color paste.

[0017] According to another aspect of the present invention, a method for preparing a microporous polyurethane sound insulation pad is provided, comprising:

[0018] 1) Prepare the mold and heat it to 40-45℃;

[0019] 2) Lay fireproof fiber cloth layers (20) in the upper and lower molds of the mold;

[0020] 3) Pour component A, heated to 40-50℃, and component B, heated to 50-60℃, into the mold respectively and mix them together, then close the mold;

[0021] 4) After curing, the mold is opened to obtain the microporous polyurethane sound insulation pad.

[0022] According to an embodiment of the present invention, the method further includes step 5), in which the vibration damping pad obtained in step 4) is placed in an oven for post-curing treatment at a temperature of 60-80°C for 2-4 hours.

[0023] The microporous polyurethane elastomer for building vibration damping and its preparation method of the present invention have several advantages, such as:

[0024] 1. The sound insulation pad containing expanded graphite and hollow glass microspheres has good sound insulation performance, with a weighted impact sound pressure level improvement of not less than 30dB.

[0025] 2. Polypropylene glycol, polytetrahydrofuran glycol and castor oil are selected as the soft segments of the polyurethane material, which gives the vibration damping pad excellent hydrolysis resistance. At the same time, the addition of a water-repellent agent can effectively prevent water from penetrating into the material and result in a low water absorption rate.

[0026] 3. The selection of appropriate soft and hard materials and their ratios ensures that the sound insulation pad has high compressive strength and good resistance to compression and creep.

[0027] 4. Fireproof fiber cloth is covered on both sides of the sound insulation pad. The microporous polyurethane core material is preferably expanded graphite with a particle size of 50-100 mesh or hollow glass microspheres with a particle size of 30-50 μm. Flame retardants are added in a certain proportion to give the sound insulation pad good fire resistance (B1 level). Attached Figure Description

[0028] The following description will detail some specific embodiments of the invention by way of example and not limitation, with reference to the accompanying drawings. The objectives and features of the invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

[0029] Appendix Figure 1 This is a schematic diagram of the structure of a microporous polyurethane sound insulation pad according to an embodiment of the present invention;

[0030] Appendix Figure 2 A photograph of a microporous polyurethane sound insulation pad prepared according to an embodiment of the present invention. Detailed Implementation

[0031] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but these are not intended to limit the scope of protection of the present invention.

[0032] refer to Figure 1 According to an embodiment of the present invention, a microporous polyurethane sound insulation mat is provided, comprising a microporous polyurethane core layer (10) and two fireproof fiber cloth layers (20) disposed on the upper and lower surfaces of the microporous polyurethane core layer (10). The total thickness of the sound insulation mat can be 3 to 25 mm, wherein the thickness of the fireproof fiber cloth layer (20) can be 0.5 to 2 mm and the thickness of the microporous polyurethane core layer (10) can be 1 to 24 mm. The fireproof fiber cloth layer (20) can be selected from various high-grade fireproof fiber cloths such as glass fiber cloth, carbon fiber cloth, basalt fiber cloth, and ceramic fiber cloth according to engineering needs; the microporous polyurethane core layer (10) is an open-cell or closed-cell material with an average pore diameter of 0.05 to 0.5 mm and a density of 150 to 400 kg / mm³. 3 .

[0033] The microporous polyurethane sound insulation pad of the present invention improves the impact sound pressure level by no less than 30 dB and its combustion performance can reach B1 level.

[0034] The following describes the specific composition and preparation process of the microporous polyurethane sound insulation pad of the present invention.

[0035] The microporous polyurethane core layer is made of microporous polyurethane elastomer. The main raw materials of microporous polyurethane elastomer include polymeric polyols, polyisocyanates, chain extenders, foaming agents, crosslinking agents, flame retardants, catalysts, and fillers. Among them, polymeric polyols and polyisocyanates are the main components of microporous polyurethane materials. Different types of polyisocyanates react with different types of polyol compounds to obtain a variety of polyurethane materials with different structures.

[0036] For microporous polyurethane elastomers, altering the structure and ratio of the soft and hard segments affects the internal structure and hydrogen bonding state, thus changing their properties. To prepare microporous polyurethane vibration damping pads with high compressive strength, low compression creep, low water absorption, high flame retardancy, and good sound insulation, appropriate soft and hard segment materials and ratios must be selected. In practice, obtaining polyurethane with satisfactory performance is not easy and requires extensive experimentation. In this invention, the inventors, through extensive research and the selection of specific raw materials and production processes, have obtained a product that meets the performance requirements for sound insulation and flame retardancy.

[0037] Microporous polyurethane elastomers can be classified into two types based on the raw materials used for the soft segments: polyester-type and polyether-type. While polyester-type polyurethanes have better mechanical properties, they are expensive, prone to hydrolysis, and have poor low-temperature resistance. Polyether polyols, on the other hand, have lower cohesive energy in their ether bonds and are easily rotated. Polyether-type polyurethanes prepared from these bonds exhibit excellent resistance to mildew, hydrolysis, low temperatures, and flexural fatigue, making them more suitable for sound insulation pad applications. Therefore, polyether polyols are selected as the soft segments for microporous polyurethane sound insulation pads. In the embodiments of this invention, castor oil polyol, polytetrahydrofuran glycol, and polypropylene glycol are preferred.

[0038] Castor oil is a type of vegetable oil containing hydroxyl groups and carbon-carbon double bonds, with ricinoleic acid triglyceride as its main component. As a soft segment in polyurethane, castor oil can improve mechanical properties. The nonpolar fatty acid chains and carbon-carbon double bonds in its molecule give it good water resistance and impart good flexibility and low-temperature performance to polyurethane.

[0039] Polytetrahydrofuran diol (PTMG1500) is a special polyether polyol. Polyurethane elastomers made from it exhibit high modulus and strength, excellent hydrolysis resistance, mildew resistance, dynamic properties, and low-temperature flexibility. Furthermore, experiments have shown that microporous polyurethane elastomers using PTMG1500 (1500 molecular weight) as the soft segment have a more regular molecular chain structure, easily forming physical cross-linking points between molecules, resulting in higher strength. Its main chain segment length is moderate, and it contains a large number of flexible ether bonds. Under dynamic vibration conditions, the soft segment molecular chains connected to the hard segments can easily reciprocate near their equilibrium positions, exhibiting a fast stress response and thus a lower dynamic-to-static modulus ratio and a lower compression set.

[0040] Polypropylene glycol can increase the flexibility of polyurethane and increase the elongation at break. Through experiments, polypropylene glycol with molecular weights of 1000 (preparation component A) and 2000 (preparation component B) were selected, which can effectively reduce the raw material cost while ensuring the material performance.

[0041] Experiments have verified that using a combination of polypropylene glycol, castor oil polyol, and polytetrahydrofuran glycol in a certain proportion as the soft segment material of the microporous polyurethane sound insulation pad results in excellent hydrolysis and mildew resistance, high compressive strength, and low compression creep.

[0042] To achieve certain sound insulation and flame retardant properties, the microporous polyurethane in this embodiment of the invention also includes hollow glass microspheres and expanded graphite. Studies have found that hollow glass microspheres and expanded graphite can simultaneously achieve good technical effects in both sound insulation and flame retardancy.

[0043] When expanded graphite is heated to a certain degree, it begins to expand, forming a thick porous carbonized layer. This carbonized layer can form a stable carbonized layer on the material surface, which can isolate the material matrix from the heat source. In addition, the carbonized layer can also isolate oxygen, prevent combustible gases from escaping, and reduce smoke generation, thereby achieving the purpose of flame retardancy.

[0044] Expanded graphite is a type of sheet-like filler. Adding expanded graphite can improve the flame retardant properties of the matrix while also enhancing the sound insulation performance of the material. This is because the presence of sheet-like fillers causes the movement of a certain macromolecular chain segment to induce the movement of more macromolecular chain segments through the filler. The internal friction generated during this movement converts sound energy into heat energy, which is then dissipated, thus improving the material's sound insulation performance. Furthermore, when sound waves reach the surface of the sheet-like filler, they are reflected. Due to the random distribution of the sheet-like filler within the material, the angle formed between the filler and the material surface is also random. From a macroscopic perspective, sound waves are scattered within the material, resulting in an increased propagation distance and increased sound energy consumption.

[0045] Hollow glass microspheres (HGM) are tiny, hollow, spherical powders. The particle size can be selected from 30-100 micrometers, preferably 30-50 μm, and the density can be 0.1-0.7 g / ml. They possess advantages such as light weight, large volume, low thermal conductivity, high compressive strength, good dispersibility, flowability, and stability. Furthermore, they exhibit excellent properties such as insulation, self-lubrication, sound insulation, water resistance, fire resistance, corrosion resistance, radiation protection, and non-toxicity. The interior of hollow glass microspheres is a rarefied gas, thus providing sound and heat insulation properties, making them an excellent filler for various thermal and sound insulation products.

[0046] Hollow glass microspheres are regular, closed spheres with uniform diameter and numerous interconnected pores. When sound waves are incident on the material's surface, some are reflected, while others pass through the surface pores into the material, causing the air inside to vibrate. This creates friction between the air molecules and the pore walls. Because the air close to the pore walls is not easily moved, and because there is also adhesion and friction between air molecules, sound energy is converted into heat energy and lost, resulting in sound wave attenuation. Simultaneously, heat exchange between the air and the pore walls causes further sound energy loss, leading to sound wave attenuation. Resonant sound-absorbing materials are equivalent to a resonant sound-absorbing structure composed of multiple Helmholtz resonators connected in parallel. When the incident sound wave approaches the system's natural frequency, the air inside the system vibrates violently, and a large amount of sound energy is converted into heat energy and lost, causing sound wave attenuation.

[0047] To further enhance the flame retardant properties of materials, flame retardants can be added during the polyurethane preparation process. Phosphate ester flame retardants, such as Fyrol PNX, can be used. Fyrol PNX is a highly efficient, halogen-free phosphate ester flame retardant with low smoke and low VOC content in the finished product. When products containing Fyrol PNX are exposed to flame, the phosphate ester decomposes upon heating to form polypyrophosphate. During decomposition, a phosphate layer is generated, forming a non-volatile protective layer that covers the burning surface, isolating it from oxygen supply and thus stopping combustion. Furthermore, because polypyrophosphate promotes the carbonization of polymers during combustion, generating a large amount of water, it also inhibits combustion. Phosphate esters thermally decompose into phosphorus pentoxide, carbon dioxide, and water during combustion, without producing toxic gases such as hydrogen chloride, making it an environmentally friendly flame retardant.

[0048] The amount of flame retardant added has a significant impact on the material properties of polyurethane elastics. Experiments have shown that as the amount of flame retardant increases, the tensile properties and elongation at break of the microporous elastomer tend to decrease, while the oxygen index does not increase significantly. Therefore, it is necessary to control the amount added within a reasonable range. In the embodiments of this invention, for example, 5 to 8 parts of flame retardant can be added.

[0049] Other chemical auxiliaries (additives) can also be added during the preparation of microporous polyurethane, such as chain extenders, crosslinking agents, foam stabilizers, cell openers, catalysts, water repellents, color pastes, water, etc. For example, the chain extender can be ethylene glycol, the crosslinking agent can be MOCA, the foam stabilizer can be B8716, the cell opener can be CJ-170, the catalyst can be amine catalyst A33, MAYCAT RA1, etc., the water repellent can be an organosilicon-based water repellent, and the color paste can be selected from JR101, BH905, etc. Those skilled in the art can select appropriate chemical auxiliaries based on the teachings of this invention and common knowledge in the field.

[0050] The present invention will be further described below with reference to specific embodiments.

[0051] Example 1

[0052] (1) Preparation of component A

[0053] a. 60 parts by weight of polypropylene glycol (PPG1000) (Shandong Dongda Chemical Industry Co., Ltd.), 50 parts by weight of polytetrahydrofuran glycol (Mitsubishi Chemical Corporation, Japan), 1.5 parts by weight of castor oil (Vertellus), 2.5 parts by weight of chain extender ethylene glycol (Mitsubishi Chemical Corporation, Japan), 2 parts by weight of crosslinking agent MOCA (Suzhou Xiangyuan Specialty Fine Chemicals Co., Ltd.), 0.6 parts by weight of distilled water, 0.2 parts by weight of catalyst A33 (Changzhou Kerry Chemical Technology Co., Ltd.), 0.5 parts by weight of foam stabilizer B8716 (Evonik Specialty Chemicals (Shanghai) Co., Ltd.), 1.5 parts by weight of cell opener CJ-170 (Shanghai Gaoqiao Petrochemical Co., Ltd.), 0.2 parts by weight of water repellent (Shanghai Kaiyin Chemical Co., Ltd.), and 6 parts by weight of flame retardant Fyrol. PNX (Israel ICL Group Industrial Products Company), 25 parts by weight of expanded graphite EG (Qingdao Jintao Graphite Co., Ltd.), 5 parts by weight of hollow glass microspheres (particle size 30-50μm, China Steel Group Maanshan Mining Research Institute New Material Technology Co., Ltd.), and 1 part by weight of color paste 076 (Inno Chemical (Shanghai) Co., Ltd.) were added to the reactor, and the valve was closed.

[0054] b. Raise the temperature of the reactor to 40℃ (35-45℃), stir and mix at 80 rpm (50-130 rpm) for 2 hours (2-3 hours);

[0055] c. Next, the viscosity, moisture content, and hydroxyl value are tested. Once they meet the standards, they are packaged for later use. The specific testing and standards are as follows: Rotational viscometer DV2T, Brookfield Company, USA, viscosity ≤3000mPa.S; Karl Fischer moisture analyzer V10S Mettler, moisture content <0.5%; Hydroxyl value: Fourier transform near-infrared spectrometer, MB3600-CH20, ABB, 60-80mgKOH / g.

[0056] (2) Preparation of component B

[0057] a. Add 80 parts by weight of polypropylene glycol (PPG2000) (Mitsubishi Chemical Corporation, Japan) to the reactor, start the heating device, set the temperature to 100°C, start the stirrer to stir at 100 rpm (80-130 rpm), when the temperature reaches 100°C, start the vacuum pump to evacuate the vacuum for 2 hours (2-3 hours).

[0058] b. Take a small sample to test the moisture content (Karl Fischer moisture analyzer, V10S Mettler, moisture content <0.1%). After the sample meets the standard, cool the reactor to 50℃ (50~60℃).

[0059] c. Slowly add 180 parts by weight of modified MDI-diphenylmethane diisocyanate (Yantai Wanhua Group, MM103C), continue stirring and mixing for 5 hours (4-6 hours), and take samples to detect the NCO content (Fourier transform near-infrared spectrometer, MB3600-CH20 type, ABB, NCO 15-20%).

[0060] d. After the target is met, the reactor is cooled to room temperature, stirring is stopped, and it is sealed for later use.

[0061] (3) Preparation of microporous polyurethane elastomer

[0062] a. Add component A to the component A raw material tank of the polyurethane foam casting machine, start stirring, heat to 45℃ (40~50℃), and keep at the temperature for 1.2 hours (1~2h);

[0063] b. Add component B to the component B raw material tank of the polyurethane foam casting machine, start stirring, heat to 50 (50~60℃), and keep at the temperature for 1.2 hours (1~2h).

[0064] c. Clean the mold, apply release agent, and control the mold temperature at 45℃ (40~45℃).

[0065] d. Lay fireproof fiber cloth (ceramic fiber cloth) on the upper and lower molds.

[0066] e. Start the polyurethane foam casting machine, set the ratio of component A to component B (molar ratio of -NCO groups in component B to -OH groups in component A (R value) to 1 to 1.02, adjust the casting speed to 120 g / s (50 to 400 g / s), calibrate the casting time to 12 s, pour the material into the mold according to the above conditions, and close the mold.

[0067] f. Cure in closed mold for 22 minutes.

[0068] g. Open the mold, take out the polyurethane microporous elastomer product, trim the edges, and put the pad into the oven for post-curing treatment at 65℃ for 2 hours.

[0069] h. After removing it, let it air dry to room temperature to obtain the microporous polyurethane sound insulation pad of Example 1 (see attached photo of the obtained product). Figure 2 ), sealed and stored for future use.

[0070] Example 2

[0071] Except for the following differences in the content of components A and B, the preparation is the same as in Example 1:

[0072] 70 parts by weight of polypropylene glycol (PPG1000), 2 parts by weight of castor oil, 28 parts by weight of expanded graphite EG, 7 parts by weight of hollow glass microspheres (particle size 30-50 μm), 220 parts by weight of modified MDI (MM103C) and 90 parts by weight of polypropylene glycol (PPG2000).

[0073] The microporous polyurethane sound insulation pad of Example 2 was finally obtained.

[0074] Comparative Example 1

[0075] Except that the preparation of component A does not contain flame retardants, the rest is the same as in Example 1.

[0076] Comparative Example 2

[0077] Except that the A component does not contain expanded graphite, the preparation is the same as in Example 1.

[0078] Comparative Example 3

[0079] Except that the preparation of component A does not contain hollow glass microspheres, the rest is the same as in Example 1.

[0080] Comparative Example 4

[0081] Except that castor oil is not included in the preparation of component A, the rest is the same as in Example 1.

[0082] Comparative Example 5

[0083] Except that the preparation of component A does not contain a hydrophobic agent, the rest is the same as in Example 1.

[0084] The formulations of Examples 1-2 and Comparative Examples 1-5 are shown in Table 1 below:

[0085] Table 1: Recipes for each example

[0086]

[0087] According to the relevant testing standards, the material's density, compressive strength, tensile properties, water absorption, sound insulation, flame retardancy, and other properties were tested. The testing standards and results are shown in Tables 2 and 3 below.

[0088] Table 2: Test Standards

[0089]

[0090] Table 3: Test Results

[0091]

[0092] Experimental results show that the product of this invention fully meets the requirements of relevant standards; it adopts specific components and combinations such as hollow glass microspheres and expanded graphite, and achieves excellent technical effects in sound insulation, flame retardancy and waterproofing, and has great practical application value.

[0093] Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-described embodiments. Any changes or modifications made by those skilled in the art without departing from the spirit of the present invention using the disclosed technical content shall be within the protection scope of the present invention.

Claims

1. A microporous polyurethane sound insulation pad, characterized in that, include: Microporous polyurethane core layer (10), and two fireproof fiber cloth layers (20) disposed on the upper and lower surfaces of the microporous polyurethane core layer (10). The microporous polyurethane core layer is prepared by the following method: The preparation of component A involves reacting 50-80 parts by weight of polypropylene glycol, 1-3 parts by weight of castor oil, 40-60 parts by weight of polytetrahydrofuran glycol, 22-30 parts by weight of expanded graphite, and 4-8 parts by weight of hollow glass microspheres to prepare component A. The preparation of component B includes reacting 170-280 parts by weight of modified MDI and 80-100 parts by weight of polyoxypropylene glycol to prepare component B; and Component A, heated to 40-50℃, and component B, heated to 50-60℃, are mixed together and reacted for 20-30 minutes to obtain microporous polyurethane. The molar ratio of -NCO groups in component B to -OH groups in component A is 1-1.

03.

2. The microporous polyurethane sound insulation pad as described in claim 1, characterized in that: The thickness of the microporous polyurethane core layer (10) is 1 to 24 mm, and the thickness of each fireproof fiber cloth layer (20) is 0.5 to 2 mm.

3. The microporous polyurethane sound insulation pad as described in claim 2, characterized in that: The polyurethane elastomer of the microporous polyurethane core layer (10) is either open-cell or closed-cell, with an average pore size of 0.05–0.5 mm and a density of 150–400 kg / m³. 3 .

4. The microporous polyurethane sound insulation pad as described in claim 1, characterized in that: The fireproof fiber cloth layer (20) is made of materials selected from glass fiber cloth, carbon fiber cloth, basalt fiber cloth and ceramic fiber cloth.

5. The microporous polyurethane sound insulation pad as described in claim 1, characterized in that: The impact sound pressure level improvement of the microporous polyurethane sound insulation pad is not less than 30 dB.

6. The microporous polyurethane sound insulation pad as described in claim 1, characterized in that: The microporous polyurethane sound insulation pad achieves a combustion rating of B1.

7. The microporous polyurethane sound insulation pad as described in claim 1, characterized in that: The preparation of component A also includes adding 5 to 8 parts by weight of flame retardant.

8. The microporous polyurethane sound insulation pad as described in claim 7, characterized in that: The step of preparing component A also includes adding 2-5 parts by weight of chain extender, 1.5-3 parts by weight of crosslinking agent, 0.5-1.2 parts by weight of water, 0.1-0.3 parts by weight of catalyst, 0.5-1 parts by weight of foam stabilizer, 1.5-2 parts by weight of cell opener, 0.1-0.3 parts by weight of water repellent and 0.8-1.5 parts by weight of color paste.

9. The microporous polyurethane sound insulation pad as described in claim 1, characterized in that: The particle size of hollow glass microspheres is 30-100μm.

10. A method for preparing a microporous polyurethane sound insulation pad according to any one of claims 1-9, comprising: 1) Prepare the mold and heat it to 40-45℃; 2) Lay fireproof fiber cloth layers (20) in the upper and lower molds of the mold; 3) Pour component A, heated to 40-50℃, and component B, heated to 50-60℃, into the mold respectively and mix them together, then close the mold; 4) After curing, the mold is opened to obtain the microporous polyurethane sound insulation pad.

11. The method according to claim 10 further includes step 5), placing the sound insulation pad obtained in step 4) into an oven for post-curing treatment at a temperature of 60-80°C for 2-4 hours.

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