Layered composite soundproofing material based on noise propagation path interruption and application

Abstract

The application discloses a layered composite sound insulation material based on noise propagation path blocking and application, and belongs to the technical field of automobile NVH noise reduction. The layered composite sound insulation material comprises, from top to bottom, a damping layer, a sound absorption layer, a sound elimination layer, a barrier layer and a buffer layer. The sound absorption layer is provided with a plurality of holes. The sound elimination layer is provided with a honeycomb structure, and the honeycomb structure is filled with paraffin microcapsules. The material realizes synchronous noise reduction of medium-high frequency noise and low frequency noise through the cooperation of the five-layer structure, and the material has good toughness and softness, and has high adhesion with automobile parts, so that the noise reduction and sound insulation effect can be further improved.

Description

Technical Field

[0001] This application relates to a layered composite sound insulation material and its application based on blocking the noise propagation path, belonging to the field of automotive NVH noise reduction technology. Background Technology

[0002] Currently, a key method for noise control in the automotive industry is to use sound insulation materials to precisely block the noise propagation path. By absorbing, reflecting, and dissipating sound waves of different frequencies and propagation patterns, materials achieve efficient noise reduction across the entire frequency range. The performance of automotive sound insulation materials directly determines the effectiveness of in-vehicle noise control. Furthermore, with the increasing demands for driving range and lightweight vehicle bodies in new energy vehicles, existing sound insulation materials are struggling to meet market needs.

[0003] Currently, the sound insulation materials widely used in the automotive field are mainly divided into three categories: porous sound-absorbing materials, dense sound insulation materials, and simple composite sound insulation materials. Among them, porous sound-absorbing materials mainly absorb sound wave energy through internal micropores, and have a certain absorption effect on mid-to-high frequency wind noise and mid-to-high frequency engine noise. However, they have problems such as loose structure and easy sound energy leakage. They also have poor blocking ability for low-frequency tire noise and low-frequency noise from body structure resonance. In addition, they are prone to water absorption and deformation in the humid environment of automobiles, resulting in a significant decrease in sound insulation performance. Long-term use is also prone to aging and peeling. Dense sound insulation materials rely on high density and high rigidity to block sound wave penetration, focusing on blocking low-frequency noise. However, their weight is relatively high, which cannot achieve automobile lightweighting and affects the range of new energy vehicles. Moreover, the manufacturing process is complex and costly. Their ability to absorb mid-to-high frequency noise is weak, making it difficult to achieve noise reduction across the entire frequency range in the vehicle. Simple composite sound insulation materials are mostly simple composites of sound-absorbing materials and dense sound insulation materials, and cannot block noise across the entire frequency range.

[0004] Chinese invention patent CN 118024483 B discloses a polyurethane composite sound insulation material and its preparation process. It mainly discloses that the polyurethane composite sound insulation material includes a sound-absorbing layer, a sound-insulating layer, and a diaphragm layer. The sound-absorbing layer has multiple irregular pores, and the diaphragm layer is located between the sound-insulating layer and the sound-absorbing layer. However, this patent only provides good noise reduction for mid-to-high frequency noise and does not effectively reduce low-frequency noise.

[0005] Therefore, there is an urgent need for a composite sound insulation material that can simultaneously block mid-to-high frequency and low-frequency noise based on the noise propagation path. Summary of the Invention

[0006] To address the aforementioned issues, a layered composite sound insulation material based on noise propagation path blocking is provided. This material achieves simultaneous noise reduction of mid-to-high frequency and low-frequency noise through a five-layer structure. At the same time, the material has good toughness and flexibility, and a high degree of conformity with automobiles, which can further improve the noise reduction effect.

[0007] One aspect of this application provides a layered composite sound insulation material based on blocking the noise propagation path, wherein the layered composite sound insulation material comprises, from top to bottom: a damping layer, a sound-absorbing layer, a sound-absorbing layer, a blocking layer, and a buffer layer;

[0008] The sound-absorbing layer has several holes;

[0009] The sound-absorbing layer has a honeycomb structure, which is filled with paraffin microcapsules.

[0010] By employing the aforementioned five-layer structure in synergy, the simultaneous reduction of mid-to-high frequency and low-frequency noise is effectively improved. The pores in the sound-absorbing layer work in conjunction with the honeycomb structure in the sound-absorbing layer to achieve a more comprehensive blockage of the noise propagation path. Compared with existing technologies, this technology solves the technical problems of traditional sound insulation materials being heavy and having poor sound insulation effects. It can achieve efficient sound insulation over a wider frequency band and effectively block the noise propagation path, while also taking into account the product's lightweight design and expanding its application range.

[0011] Optionally, the thickness of the damping layer is 0.3-0.5 mm;

[0012] The thickness of the sound-absorbing layer is 2-5mm;

[0013] The thickness of the sound-absorbing layer is 2-3 mm;

[0014] The thickness of the barrier layer is 0.05-0.1 mm;

[0015] The thickness of the buffer layer is 1-2 mm.

[0016] Optionally, the damping layer comprises, by mass fraction:

[0017] The damping layer comprises, by mass fraction: 90-110 parts modified butadiene rubber, 3-8 parts modified graphene, and 15-30 parts damping filler.

[0018] The sound-absorbing layer comprises, by mass fraction: 90-110 parts of a porous substrate, 10-25 parts of sound-absorbing filler, 5-12 parts of a first adhesive, 3-8 parts of a flame retardant, and 40-50 parts of a solvent.

[0019] The sound-absorbing layer comprises, by mass fraction: 90-110 parts of TPV thermoplastic elastomer, 3-6 parts of plasticizer, 0.5-1 part of antioxidant, and 20-35 parts of paraffin microcapsules.

[0020] The barrier layer includes an aluminum foil layer and a polyethylene terephthalate layer, wherein the thickness ratio of the aluminum foil layer to the polyethylene terephthalate layer is 1:(0.1-0.5).

[0021] The buffer layer is made of polyester fiber nonwoven fabric.

[0022] Optionally, the damping filler includes at least one of mica, talc, and hollow glass microspheres.

[0023] Optionally, the first adhesive includes one of water-based acrylic resin and EVA emulsion.

[0024] Optionally, the porous substrate includes one of melamine foam and polyurethane foam.

[0025] Optionally, the sound-absorbing layer further includes an elastic membrane, the elastic membrane being made of thermoplastic polyurethane (TPU).

[0026] Optionally, the basis weight of the polyester fiber nonwoven fabric is 180-250 gsm.

[0027] Preferably, the basis weight of the polyester fiber nonwoven fabric is 200 gsm.

[0028] Within this weight range, the polyester fiber nonwoven fabric has a moderate density and uniform pores, ensuring sufficient interconnected micropores between the polyester fibers to efficiently absorb incident sound waves. The sound energy is dissipated as heat energy through friction and viscous resistance between the polyester fibers and air molecules. At the same time, it avoids the problem of excessively large pores and sparse polyester fiber interweaving structure caused by excessively low weight, which would result in high sound wave penetration. In addition, within this weight range, the polyester fiber nonwoven fabric material has a certain degree of softness, which makes it more compatible with automotive parts.

[0029] Optionally, the method for preparing the modified butadiene rubber includes the following steps:

[0030] S1: Add 1,3-butadiene monomer to a solvent, then add a structure modifier to obtain the first mixed solution;

[0031] S2: Add an initiator to the first mixed solution to react and obtain polybutadiene with a vinyl content of 45-55 wt%;

[0032] S3: After the conversion rate of 1,3-butadiene monomer is greater than 96%, a coupling agent is added for coupling, followed by the addition of naphthenic oil for modification, then an antioxidant is added to terminate the reaction, and after dehydration and drying, modified butadiene rubber is obtained.

[0033] The 1,3-butadiene monomer is polymerized using an initiator, and the addition of a structure modifier allows the vinyl content in the polybutadiene to be stabilized at 45–55 wt%. Within this range, the vinyl content exhibits high damping effect, good tensile strength, and moderate flexibility. Vinyl groups, being side double bonds, increase intramolecular friction, converting vibrational and acoustic energy into heat energy, thus improving sound insulation, vibration damping, and noise reduction. If the vinyl content is too low, the material prepared using modified butadiene rubber will be too soft, resulting in insufficient overall strength. Conversely, if the vinyl content is too high, the material prepared using modified butadiene rubber will have increased hardness and decreased elasticity, reducing noise barrier effectiveness and affecting its fit with automotive parts. The polybutadiene obtained in step S2 forms a star-shaped structure under the action of a coupling agent, thereby improving the tear resistance of the sound insulation material. Subsequently, naphthenic oil is added for oil-filled modification, improving the material's flexibility and processing performance, allowing the resulting product to better fit with automotive parts and further enhancing noise transmission barrier properties.

[0034] Optionally, the amount of solvent added is 3 to 6 times the mass of the 1,3-butadiene monomer.

[0035] Optionally, the amount of the structure modifier added is 0.1-1% of the mass of the 1,3-butadiene monomer.

[0036] At this addition level, the proportion of 1,2-addition can be increased, ensuring the vinyl content meets the target requirements without excessive complexation of the initiator, resulting in stable mechanical properties of the prepared modified butadiene rubber. If the addition amount of the structure modifier is too low, the vinyl content in the modified butadiene rubber will be too low, leading to decreased damping performance and poorer sound insulation and vibration reduction effects. If the addition amount of the structure modifier is too high, it may inhibit the polymerization of 1,3-butadiene monomers, reducing initiation efficiency and thus affecting the quality of the modified butadiene rubber.

[0037] Optionally, the structure modifier includes at least one of tetrahydrofuran, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, N,N,N',N'-tetramethylethylenediamine, and hexamethylphosphoric triamine.

[0038] Optionally, the amount of initiator added is 0.05-0.2% of the mass of 1,3-butadiene monomer.

[0039] At this dosage, the polymerization of 1,3-butadiene monomer can be effectively initiated, and the vinyl content in the modified butadiene rubber can be controlled, giving the rubber good mechanical strength, resilience, and processing fluidity. It also facilitates the efficient execution of subsequent coupling reactions, forming a uniformly structured star-shaped polymer. If too much initiator is added, the reaction may be too rapid, making the reaction rate difficult to control and increasing the consumption of subsequent coupling agents, thus reducing coupling efficiency. Conversely, if too little initiator is added, the polymerization rate may be slow, and processing performance may deteriorate.

[0040] Optionally, the initiator includes n-butyllithium.

[0041] Optionally, the amount of coupling agent added is 0.05-0.3% of the mass of the 1,3-butadiene monomer.

[0042] At this addition level, the active polybutadiene chains can undergo efficient coupling, forming a well-structured star-shaped polymer. This improves the mechanical strength, resilience, fatigue resistance, processing flowability, and molding stability of the material prepared using this modified butadiene rubber. If the amount of coupling agent added is too low, the coupling effect will be insufficient, resulting in a low proportion of star-shaped structures, which will reduce the mechanical and damping properties of the modified butadiene rubber. If the amount of coupling agent added is too high, it can easily lead to over-coupling, increased byproducts, and increased difficulty in subsequent processing.

[0043] Optionally, the coupling agent includes one of tin tetrachloride and silicon chloride.

[0044] Optionally, the amount of antioxidant added is 0.2%-0.6% of the total mass of the reaction system.

[0045] Optionally, the antioxidant includes one of antioxidant 264, antioxidant 1076, and antioxidant 168.

[0046] Optionally, the amount of naphthenic oil added is 10%-15% of the total mass of the reaction system.

[0047] At this addition level, the processing fluidity and moldability of modified butadiene rubber can be improved; at the same time, the softness, elasticity and damping sound insulation properties of modified butadiene rubber are enhanced. Meanwhile, the naphthenic oil has good compatibility with polybutadiene and is not prone to problems such as oil separation and seepage.

[0048] Optionally, the reaction temperature in step S2 is 45-60℃ and the reaction time is 2.5-3.5h.

[0049] Optionally, the preparation method of the modified graphene includes the following steps:

[0050] A1: Mix graphene oxide with a solvent, then add an alkaline solution and stir until homogeneous. Then, perform ultrasonic treatment, centrifuge to remove the precipitate, and dry to obtain alkali-modified graphene oxide.

[0051] A2: Add silane coupling agent solution to alkali-modified graphene oxide, react at 60-80℃ for 1-2 hours, wash and dry to obtain modified graphene oxide.

[0052] First, graphene oxide is activated, expanded, and dispersed using an alkaline solution, and then chemically grafted and modified using a silane coupling agent. The resulting modified graphene oxide exhibits high surface activity and good dispersibility.

[0053] Optionally, the amount of solvent added is 700-900 times that of graphene oxide.

[0054] Optionally, the alkaline solution includes one of sodium hydroxide solution and potassium hydroxide solution.

[0055] Optionally, the concentration of the alkaline solution is 0.4-0.6 mg / mL.

[0056] Optionally, the amount of alkaline solution added is 5-10 times the mass of graphene oxide.

[0057] Optionally, the silane coupling agent is one of KH-550, KH-560, and KH-570.

[0058] Optionally, the amount of the silane coupling agent solution added is 50-80 times the mass of the alkali-modified graphene oxide.

[0059] Optionally, the silane coupling agent solution is a silane coupling agent ethanol solution, and the concentration of the silane coupling agent solution is 4wt%-6wt%.

[0060] Optionally, the ultrasonic treatment time in step A1 is 50-70 minutes.

[0061] Optionally, step A1 may include a reflux treatment before ultrasound, wherein the reflux treatment step is to reflux at 80-100°C for 80-100 min.

[0062] This step enhances the effect of alkaline solution on graphene oxide in a high-temperature, sealed environment, increasing the number of surface active groups, promoting sheet exfoliation, reducing agglomeration, and improving the reactivity of graphene oxide. Simultaneously, this reflux treatment, combined with subsequent ultrasonication, significantly improves the grafting rate and interfacial bonding strength of the silane coupling agent, resulting in more uniform dispersion of modified graphene oxide in the matrix and stronger interfacial bonding, thereby enhancing the overall performance of the composite material.

[0063] Another aspect of this application provides a method for preparing a layered composite sound insulation material based on noise propagation path blocking, comprising the following steps:

[0064] (1) The damping layer is prepared by stirring and mixing modified butadiene rubber, modified graphene and damping filler at 60-80℃ for 20-40 min to obtain a damping premix, and then melting and blending at 100-160℃ and extruding to obtain a damping layer.

[0065] (2) The sound-absorbing layer is prepared by mixing the sound-absorbing filler, the first binder, the flame retardant and the solvent to obtain a slurry, then immersing the substrate containing pores into the slurry for 10-30 seconds, and drying to obtain the sound-absorbing layer.

[0066] (3) The method for preparing the sound-absorbing layer is to mix TPV thermoplastic elastomer, plasticizer and antioxidant at 160-180℃, and then calender to obtain an elastic substrate. The substrate is then treated with a mold at 170-190℃ and 0.4-0.6MPa for 30-60s to obtain an elastic substrate containing a honeycomb structure. One side of the elastic substrate containing the honeycomb structure has an opening of the honeycomb structure. Paraffin microcapsules are filled into the honeycomb structure through the opening. Then, an elastic film is covered on the side of the elastic substrate containing the honeycomb structure with the opening of the honeycomb structure to obtain the sound-absorbing layer.

[0067] (4) Preparation method of barrier layer: The aluminum foil layer and the polyethylene terephthalate layer are treated at 150-170℃ and 0.6-0.8MPa for 3-5 min to obtain the barrier layer;

[0068] (5) The buffer layer, barrier layer, sound-absorbing layer, sound-absorbing layer and damping layer are bonded together layer by layer from bottom to top with the second adhesive, and then pressure is applied for curing to obtain the layered composite sound insulation material.

[0069] Optionally, the pore diameter of the cavity in the honeycomb structure is 3-8 mm and the pore depth is 1-2.5 mm.

[0070] Optionally, the curing temperature of the pressure curing in step (5) is 70-90℃, the pressure is 0.3-0.6MPa, and the curing time is 8-12min.

[0071] Optionally, the preparation method of the second adhesive includes the following steps: heating 40-50 parts of acrylic acid to 80-85°C, adding 15-20 parts of butyl rubber, 18-22 parts of rosin resin and 2-4 parts of compatibilizer, stirring and mixing evenly, then adding 1-3 parts of titanate coupling agent, continuing to stir and mix, and finally adding 2-4 parts of crosslinking agent, heating to 95-105°C, stirring and mixing evenly to obtain the second adhesive.

[0072] In another aspect of this application, the layered composite sound insulation material based on noise propagation path blocking described above, or the preparation method of the layered composite sound insulation material based on noise propagation path blocking described above, is used in the body, doors, engine compartment, and chassis of automobiles.

[0073] The beneficial effects of this application include, but are not limited to:

[0074] 1. The layered composite sound insulation material based on noise propagation path blocking according to this application achieves full-band sound wave absorption and vibration isolation through the synergistic effect of the five-layer structure. At the same time, each layer in this application is a flexible layer, which can avoid the secondary noise generated by vibration transmission between layers and improve the vibration reduction and noise reduction effect.

[0075] 2. The layered composite sound insulation material based on noise propagation path blocking according to this application has a relatively thin overall thickness. Combined with the fact that each layer is a flexible layer, it can not only effectively reduce vibration and noise and reduce the overall weight of the material, but also improve the fit with automotive parts and further improve the utilization of the layered composite sound insulation material.

[0076] 3. The layered composite sound insulation material based on noise propagation path blocking according to this application combines the effects of sound absorption and vibration reduction through the synergistic cooperation of the sound absorption layer and the barrier layer, so that the layered composite sound material can simultaneously achieve multiple effects of sound absorption, vibration reduction and barrier. Detailed Implementation

[0077] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0078] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application were all purchased commercially.

[0079] Unless otherwise specified, the methods used in the embodiments and comparative examples of this application are conventional methods in the prior art.

[0080] In the embodiments and comparative examples of this application, the plasticizer is epoxidized soybean oil (CAS No.: 8013-07-8), the antioxidant is antioxidant 2246, the naphthenic oil is naphthenic oil 4010, the sound-absorbing filler is diatomaceous earth, the flame retardant is aluminum hydroxide, and the compatibilizer is maleic anhydride grafted butyl rubber.

[0081] In the embodiments and comparative examples of this application, the aluminum foil layer and the polyethylene terephthalate layer were prepared by methods in the prior art. Those skilled in the art can choose according to the actual situation, and the preparation method does not constitute a limitation on this application.

[0082] The polyurethane foam and melamine foam in the embodiments and comparative examples of this application are prepared by commonly used technical solutions in the field. As long as the polyurethane foam and melamine foam have a certain number of pores, their preparation methods do not constitute a limitation on this application.

[0083] The hollow glass microspheres in the embodiments and comparative examples of this application were purchased from Shanghai Huijing Asia Nanomaterials Co., Ltd., the paraffin microcapsules were purchased from Hangzhou Feijie Technology Co., Ltd., the particle size of the paraffin microcapsules was 20 μm, and the phase transition temperature was 26-27℃; the TPV thermoplastic elastomer was purchased from Celanese Chemical Co., Ltd.

[0084] CAS No. for waterborne acrylic resin: 25767-39-9; CAS No. for 1,3-butadiene: 106-99-0; CAS No. for n-butyllithium: 109-72-8; CAS No. for tin tetrachloride: 7646-78-8; CAS No. for acrylic acid: 79-10-7; CAS No. for butyl rubber: 9010-85-9; CAS No. for rosin resin: 85026-55-7; CAS No. for divinylbenzene: 1321-74-0.

[0085] The molds used in the embodiments and comparative examples of this application are commonly used molds for preparing honeycomb structures in the prior art. They can be molds composed of several hollow cylinders with hexagonal cross-sections to prepare honeycomb structures. Other types of structural molds can also be used, as long as they can prepare honeycomb structures.

[0086] The elastic membrane in the embodiments and comparative examples of this application is made of thermoplastic polyurethane (TPU), and the thickness of the elastic membrane is 0.1 mm.

[0087] Example 1

[0088] This embodiment relates to a layered composite sound insulation material based on blocking the noise propagation path. The layered composite sound insulation material includes, from top to bottom: a damping layer, a sound-absorbing layer, a sound-absorbing layer, a barrier layer, and a buffer layer.

[0089] The sound-absorbing layer has several pores;

[0090] The sound-absorbing layer has a honeycomb structure, which is filled with paraffin microcapsules;

[0091] The damping layer is 0.3 mm thick; the sound-absorbing layer is 2 mm thick; the sound-absorbing layer is 3 mm thick; the barrier layer is 0.1 mm thick; and the buffer layer is 2 mm thick.

[0092] The damping layer, by mass fraction, comprises: 90 parts modified butadiene rubber, 3 parts modified graphene, and 15 parts mica.

[0093] The sound-absorbing layer, by mass fraction, comprises: 110 parts of melamine foam substrate, 25 parts of diatomaceous earth, 12 parts of water-based acrylic resin, 3 parts of flame retardant, and 40 parts of water.

[0094] The sound-absorbing layer, by mass fraction, comprises: 90 parts TPV thermoplastic elastomer, 3 parts plasticizer, 0.5 parts antioxidant, and 20 parts paraffin microcapsules;

[0095] The barrier layer includes an aluminum foil layer and a polyethylene terephthalate layer, wherein the thickness ratio of the aluminum foil layer to the polyethylene terephthalate layer is 1:0.5.

[0096] The buffer layer is made of polyester fiber nonwoven fabric, and the unit area weight of the polyester fiber nonwoven fabric is 250 gsm.

[0097] The preparation method of layered composite sound insulation material based on noise propagation path blocking includes the following steps:

[0098] (1) The damping layer is prepared by stirring and mixing modified butadiene rubber, modified graphene and mica at 60°C for 20 min to obtain a damping premix, then melting and blending at 160°C and extruding to obtain a damping layer.

[0099] The preparation method of modified butadiene rubber includes the following steps:

[0100] S1: Add 1,3-butadiene monomer to 3 times the amount of cyclohexane, then add 0.1% tetrahydrofuran by mass of 1,3-butadiene monomer to obtain the first mixed solution;

[0101] S2: Add 0.05% by mass of n-butyllithium (1,3-butadiene monomer) to the first mixed solution and react at 45°C for 3.5 h to obtain polybutadiene with a vinyl content of 45 wt%.

[0102] S3: After the conversion rate of 1,3-butadiene monomer is greater than 96%, 0.05% of tin tetrachloride by mass of 1,3-butadiene monomer is added for coupling. Then, 10% of naphthenic oil by mass of total reaction system is added for modification. After that, 0.2% of antioxidant 264 by mass of total reaction system is added. Ethanol is added to terminate the reaction. After dehydration and drying, modified butadiene rubber is obtained.

[0103] The preparation method of modified graphene includes the following steps:

[0104] A1: Mix graphene oxide with 700 times the amount of water, then add 5 times the mass of graphene oxide in a 0.4 mg / mL sodium hydroxide solution, stir and mix thoroughly, reflux at 80℃ for 100 min, then sonicate at 200 W for 50 min, centrifuge at 10000 r / min for 60 min, discard the precipitate, collect the supernatant, add acetic acid to adjust to neutral, and dry to obtain alkali-modified graphene oxide;

[0105] A2: Add 50 times the mass of silane coupling agent KH-550 solution to alkali-modified graphene oxide. The concentration of silane coupling agent KH-550 solution is 4wt%. React at 60℃ for 2h. After washing and drying, modified graphene oxide is obtained.

[0106] (2) The sound-absorbing layer is prepared by mixing diatomaceous earth, water-based acrylic resin, flame retardant and water to obtain a slurry, then immersing melamine foam substrate in the slurry for 30 seconds, and drying to obtain the sound-absorbing layer.

[0107] (3) The sound-absorbing layer is prepared by mixing TPV thermoplastic elastomer, plasticizer and antioxidant at 180°C, then calendering to obtain an elastic substrate, and treating it with a mold at 190°C and 0.4MPa for 60s to obtain an elastic substrate containing a honeycomb structure. One side of the elastic substrate containing the honeycomb structure has an opening of the honeycomb structure. Paraffin microcapsules are filled into the honeycomb structure through the opening. Then, an elastic film is covered on the side of the elastic substrate containing the honeycomb structure with the opening of the honeycomb structure to obtain the sound-absorbing layer. The pore size of the cavity in the honeycomb structure is 3mm and the pore depth is 2.5mm.

[0108] (4) Preparation method of barrier layer: The aluminum foil layer and the polyethylene terephthalate layer are treated at 150℃ and 0.8MPa for 5min to obtain the barrier layer;

[0109] (5) The buffer layer, barrier layer, sound-absorbing layer, sound-absorbing layer and damping layer are bonded together layer by layer from bottom to top with the second adhesive. Then, the layered composite sound insulation material is obtained by curing at a curing temperature of 70℃, a pressure of 0.6MPa and a curing time of 12min.

[0110] The preparation method of the second adhesive includes the following steps: heating 50 parts of acrylic acid to 80°C, adding 20 parts of butyl rubber, 22 parts of rosin resin and 4 parts of compatibilizer, stirring and mixing evenly, then adding 3 parts of titanate coupling agent KR-138S, continuing to stir and mix, and finally adding 4 parts of divinylbenzene, heating to 105°C, stirring and mixing evenly to obtain the second adhesive.

[0111] Example 2

[0112] This embodiment relates to a layered composite sound insulation material based on blocking the noise propagation path. The layered composite sound insulation material includes, from top to bottom: a damping layer, a sound-absorbing layer, a sound-absorbing layer, a barrier layer, and a buffer layer.

[0113] The sound-absorbing layer has several pores;

[0114] The sound-absorbing layer has a honeycomb structure, which is filled with paraffin microcapsules;

[0115] The damping layer is 0.5 mm thick; the sound-absorbing layer is 5 mm thick; the sound-absorbing layer is 2 mm thick; the barrier layer is 0.05 mm thick; and the buffer layer is 1 mm thick.

[0116] The damping layer, by mass fraction, comprises: 110 parts modified butadiene rubber, 8 parts modified graphene, and 30 parts talc.

[0117] The sound-absorbing layer, by mass fraction, comprises: 90 parts polyurethane foam substrate, 10 parts diatomaceous earth, 5 parts EVA emulsion, 8 parts flame retardant, and 50 parts water.

[0118] The sound-absorbing layer, by mass fraction, comprises: 110 parts TPV thermoplastic elastomer, 6 parts plasticizer, 1.5 parts antioxidant, and 35 parts paraffin microcapsules.

[0119] The barrier layer includes an aluminum foil layer and a polyethylene terephthalate layer, wherein the thickness ratio of the aluminum foil layer to the polyethylene terephthalate layer is 1:0.1.

[0120] The buffer layer is made of polyester fiber nonwoven fabric, and the unit area weight of the polyester fiber nonwoven fabric is 180 gsm.

[0121] The preparation method of layered composite sound insulation material based on noise propagation path blocking includes the following steps:

[0122] (1) The damping layer is prepared by stirring and mixing modified butadiene rubber, modified graphene and talc powder at 60°C for 20 min to obtain a damping premix, then melting and blending at 160°C and extruding to obtain a damping layer.

[0123] The preparation method of modified butadiene rubber includes the following steps:

[0124] S1: Add 1,3-butadiene monomer to 6 times the amount of cyclohexane, then add 1% by mass of diethylene glycol dimethyl ether of 1,3-butadiene monomer to obtain the first mixed solution;

[0125] S2: Add 0.2% by mass of n-butyllithium (1,3-butadiene monomer) to the first mixed solution and react at 60°C for 2.5 h to obtain polybutadiene with a vinyl content of 55 wt%.

[0126] S3: After the conversion rate of 1,3-butadiene monomer is greater than 96%, 0.3% of tin tetrachloride by mass of 1,3-butadiene monomer is added for coupling. Then, 15% of naphthenic oil by mass of the total reaction system is added for modification. Next, 0.6% of antioxidant 1076 by mass of the total reaction system is added. Ethanol is added to terminate the reaction. After dehydration and drying, modified butadiene rubber is obtained.

[0127] The preparation method of modified graphene includes the following steps:

[0128] A1: Mix graphene oxide with 900 times the amount of water, then add 10 times the mass of graphene oxide in a 0.6 mg / mL potassium hydroxide solution, stir and mix thoroughly, reflux at 100℃ for 80 min, then sonicate at 200 W for 70 min, centrifuge at 10000 r / min for 60 min, discard the precipitate, collect the supernatant, add acetic acid to adjust to neutral, and dry to obtain alkali-modified graphene oxide;

[0129] A2: Add 80 times the mass of silane coupling agent KH-560 solution to alkali-modified graphene oxide. The concentration of silane coupling agent KH-560 solution is 6wt%. React at 80℃ for 1h. After washing and drying, modified graphene oxide is obtained.

[0130] (2) The sound-absorbing layer is prepared by mixing diatomaceous earth, EVA emulsion, flame retardant and water to obtain a slurry, then immersing polyurethane foam substrate in the slurry for 10 seconds and drying to obtain the sound-absorbing layer.

[0131] (3) The sound-absorbing layer is prepared by mixing TPV thermoplastic elastomer, plasticizer and antioxidant at 160°C, then calendering to obtain an elastic substrate, and treating it with a mold at 170°C and 0.6MPa for 30s to obtain an elastic substrate containing a honeycomb structure. One side of the elastic substrate containing the honeycomb structure has an opening of the honeycomb structure. Paraffin microcapsules are filled into the honeycomb structure through the opening. Then, an elastic film is covered on the side of the elastic substrate containing the honeycomb structure with the opening of the honeycomb structure to obtain the sound-absorbing layer. The pore size of the cavity in the honeycomb structure is 8mm and the pore depth is 1mm.

[0132] (4) Preparation method of barrier layer: The aluminum foil layer and the polyethylene terephthalate layer are treated at 170℃ and 0.6MPa for 3min to obtain the barrier layer;

[0133] (5) The buffer layer, barrier layer, sound-absorbing layer, sound-absorbing layer and damping layer are bonded together layer by layer from bottom to top with the second adhesive. Then, the layered composite sound insulation material is obtained by curing at a curing temperature of 90℃, a pressure of 0.3MPa and a curing time of 8min.

[0134] The preparation method of the second adhesive includes the following steps: heating 40 parts of acrylic acid to 85°C, adding 15 parts of butyl rubber, 18 parts of rosin resin and 2 parts of compatibilizer, stirring and mixing evenly, then adding 1 part of titanate coupling agent KR-138S, continuing to stir and mix, and finally adding 2 parts of divinylbenzene, heating to 95°C, stirring and mixing evenly to obtain the second adhesive.

[0135] Example 3

[0136] This embodiment relates to a layered composite sound insulation material based on blocking the noise propagation path. The layered composite sound insulation material includes, from top to bottom: a damping layer, a sound-absorbing layer, a sound-absorbing layer, a barrier layer, and a buffer layer.

[0137] The sound-absorbing layer has several pores;

[0138] The sound-absorbing layer has a honeycomb structure, which is filled with paraffin microcapsules;

[0139] The damping layer has a thickness of 0.4 mm; the sound-absorbing layer has a thickness of 4 mm; the sound-absorbing layer has a thickness of 2.5 mm; the barrier layer has a thickness of 0.08 mm; and the buffer layer has a thickness of 1.5 mm.

[0140] The damping layer, by mass fraction, comprises: 100 parts modified butadiene rubber, 5 parts modified graphene, and 25 parts hollow glass microspheres.

[0141] The sound-absorbing layer, by mass fraction, comprises: 100 parts melamine foam substrate, 20 parts diatomaceous earth, 8 parts water-based acrylic resin, 6 parts flame retardant, and 45 parts water.

[0142] The sound-absorbing layer, by mass fraction, comprises: 100 parts TPV thermoplastic elastomer, 4 parts plasticizer, 0.8 parts antioxidant, and 25 parts paraffin microcapsules.

[0143] The barrier layer includes an aluminum foil layer and a polyethylene terephthalate layer, wherein the thickness ratio of the aluminum foil layer to the polyethylene terephthalate layer is 1:0.375.

[0144] The buffer layer is made of polyester fiber nonwoven fabric, and the unit area weight of the polyester fiber nonwoven fabric is 200 gsm.

[0145] The preparation method of layered composite sound insulation material based on noise propagation path blocking includes the following steps:

[0146] (1) The damping layer is prepared by stirring and mixing modified butadiene rubber, modified graphene and hollow glass microspheres at 70°C for 30 min to obtain a damping premix, then melting and blending at 130°C and extruding to obtain a damping layer.

[0147] The preparation method of modified butadiene rubber includes the following steps:

[0148] S1: Add 1,3-butadiene monomer to 5 times the amount of cyclohexane, then add 0.5% by mass of tetrahydrofuran to obtain the first mixed solution;

[0149] S2: Add 0.1% by mass of n-butyllithium (1,3-butadiene monomer) to the first mixed solution and react at 50°C for 3 hours to obtain polybutadiene with a vinyl content of 50 wt%.

[0150] S3: After the conversion rate of 1,3-butadiene monomer is greater than 96%, 0.2% of tin tetrachloride by mass of 1,3-butadiene monomer is added for coupling. Then, 13% of naphthenic oil by mass of total reaction system is added for modification. Next, 0.4% of antioxidant 264 by mass of total reaction system is added. Ethanol is added to terminate the reaction. After dehydration and drying, modified butadiene rubber is obtained.

[0151] The preparation method of modified graphene includes the following steps:

[0152] A1: Mix graphene oxide with 800 times the amount of water, then add 6 times the mass of graphene oxide in a 0.5 mg / mL sodium hydroxide solution, stir and mix evenly, reflux at 90℃ for 90 min, then sonicate at 200 W for 60 min, centrifuge at 10000 r / min for 60 min, discard the precipitate, collect the supernatant, add acetic acid to adjust to neutral, and dry to obtain alkali-modified graphene oxide;

[0153] A2: Add 60 times the mass of silane coupling agent KH-550 solution to alkali-modified graphene oxide. The concentration of silane coupling agent KH-550 solution is 5wt%. React at 70℃ for 1.5h. After washing and drying, modified graphene oxide is obtained.

[0154] (2) The sound-absorbing layer is prepared by mixing diatomaceous earth, water-based acrylic resin, flame retardant and water to obtain a slurry, then immersing melamine foam substrate in the slurry for 20 seconds and drying to obtain the sound-absorbing layer.

[0155] (3) The method for preparing the sound-absorbing layer is to mix TPV thermoplastic elastomer, plasticizer and antioxidant at 170°C, and then calender to obtain an elastic substrate. The substrate is then treated at 180°C and 0.5MPa for 50s using a mold to obtain an elastic substrate containing a honeycomb structure. One side of the elastic substrate containing the honeycomb structure has an opening of the honeycomb structure. Paraffin microcapsules are filled into the honeycomb structure through the opening. Then, an elastic film is covered on the side of the elastic substrate containing the honeycomb structure with the opening of the honeycomb structure to obtain the sound-absorbing layer.

[0156] The pore diameter of the hollow cavity in the honeycomb structure is 6mm and the pore depth is 2mm;

[0157] (4) Preparation method of barrier layer: The aluminum foil layer and the polyethylene terephthalate layer are treated at 160℃ and 0.7MPa for 4min to obtain the barrier layer;

[0158] (5) The buffer layer, barrier layer, sound-absorbing layer, sound-absorbing layer and damping layer are bonded together layer by layer from bottom to top with the second adhesive. Then, the layered composite sound insulation material is obtained by curing at a curing temperature of 80℃, a pressure of 0.5MPa and a curing time of 10min.

[0159] The preparation method of the second adhesive includes the following steps: heating 45 parts of acrylic acid to 85°C, adding 18 parts of butyl rubber, 20 parts of rosin resin and 3 parts of compatibilizer, stirring and mixing evenly, then adding 2 parts of titanate coupling agent KR-138S, continuing to stir and mix, and finally adding 3 parts of divinylbenzene, heating to 100°C, stirring and mixing evenly to obtain the second adhesive.

[0160] Example 4

[0161] The difference between this embodiment and embodiment 3 is that the thickness of the damping layer is 1.0 mm, while the rest is the same as in embodiment 3.

[0162] Example 5

[0163] The difference between this embodiment and embodiment 3 is that the thickness of the barrier layer is 0.4 mm, while the rest is the same as in embodiment 3.

[0164] Example 6

[0165] The difference between this embodiment and embodiment 3 is that the thickness of the buffer layer is 0.2 mm, while the rest is the same as in embodiment 3.

[0166] Example 7

[0167] The difference between this embodiment and embodiment 3 is that the thickness ratio of the aluminum foil layer to the polyethylene terephthalate layer in the barrier layer is 1:1, while the rest is the same as in embodiment 3.

[0168] Comparative Example 1

[0169] The difference between this comparative example and Example 3 is that no damping layer is added; otherwise, it is the same as Example 3.

[0170] Comparative Example 2

[0171] The difference between this comparative example and Example 3 is that the melamine foam substrate in the sound-absorbing layer is replaced with polyester fiber nonwoven fabric, while the rest is the same as in Example 3.

[0172] Comparative Example 3

[0173] The difference between this comparative example and Example 3 is that: in step (3), a mold is not used to prepare the honeycomb structure, but only an elastic sheet obtained by direct calendering is used. The rest is the same as in Example 3.

[0174] Comparative Example 4

[0175] The difference between this comparative example and Example 3 is that no paraffin microcapsules are added to the sound-absorbing layer; otherwise, they are the same as in Example 3.

[0176] Comparative Example 5

[0177] The difference between this comparative example and Example 3 is that the modified butadiene rubber in the damping layer is replaced with butadiene rubber, while the rest is the same as in Example 3.

[0178] Comparative Example 6

[0179] The difference between this comparative example and Example 3 is that the modified graphene in the damping layer is replaced with graphene, while the rest is the same as in Example 3.

[0180] Comparative Example 7

[0181] The difference between this comparative example and Example 3 is that the barrier layer is only an aluminum foil layer, without the addition of a polyethylene terephthalate layer; the rest is the same as in Example 3.

[0182] Test Example 1

[0183] 1. The test methods and conditions for sound insulation in the mid-to-high frequency range (500-8000Hz) are as follows:

[0184] (1) Conditions: Two reverberation chambers (source chamber + receiving chamber), with an area of ​​50m². 2 ; Specimen opening: 10±0.5m, with strict sealing around the perimeter; Sound source: dodecahedral omnidirectional sound source, pink noise / white noise, mid-to-high frequency selection of 500, 4000 and 8000HZ for data testing, and finally take the average value;

[0185] (2) Measurement steps:

[0186] a. Measure the background noise in the receiving room (must be ≥10dB lower than the measured value);

[0187] b. Sound source chamber emits sound, and the sound pressure level is measured at 1 / 3 octave band; Sound source chamber: 12 fixed measuring points, and the spatial average value is taken; Receiving chamber: 12 fixed points are measured, and the spatial average value is taken;

[0188] c. Measure the reverberation time T60 of the receiving chamber (0.3-1.5s);

[0189] d. Calculate the sound insulation R, R = L1 - L2 + 10log(S / A), where L1: average sound pressure level in the source chamber; L2: average sound pressure level in the receiving chamber; S: area of ​​the specimen; A: sound absorption of the receiving chamber (A = 0.161V / T60), where V refers to the internal volume of the receiving chamber in meters. 3 ;

[0190] 2. The test method for the sound absorption coefficient in the low frequency range of 20-500Hz is to refer to the reverberation chamber method for sound absorption coefficient in GB / T20247-2006. Data are tested at 20, 100, and 450Hz respectively, and the average value is taken.

[0191] 3. The bonding rate is tested by measuring the ratio of the actual bonding area between the sound insulation material and the automotive body sheet metal / interior substrate to the theoretical bonding area. The formula and measurement method for the bonding rate are as follows:

[0192] a. Following the actual vehicle assembly process, lay and press the composite sound insulation material onto the simulated curved surface substrate, maintaining a pressure of 0.02-0.05MPa for 30 seconds;

[0193] b. Inject low-pressure, low-flow-rate tracer gas (such as air) uniformly into the interface between the material and the substrate, and record the non-adhesive area using a pressure-sensitive membrane / ultrasonic imaging method;

[0194] c. Using an image acquisition and processing system, identify and calculate: the area A of the gap where the parts are not properly bonded. i Theoretical total bonding area A o ;

[0195] d. The formula for calculating the fit rate is n=4 (A o- A i ) / A o* 100%; see Table 1 for specific test results.

[0196] Table 1

[0197]

[0198] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A layered composite sound insulation material based on blocking noise propagation paths, characterized in that, The layered composite sound insulation material comprises, from top to bottom: a damping layer, a sound-absorbing layer, a sound-absorbing layer, a barrier layer, and a buffer layer; The damping layer comprises, by mass fraction: 90-110 parts modified butadiene rubber, 3-8 parts modified graphene, and 15-30 parts damping filler. The sound-absorbing layer comprises, by mass fraction: 90-110 parts of a porous substrate, 10-25 parts of sound-absorbing filler, 5-12 parts of a first adhesive, 3-8 parts of a flame retardant, and 40-50 parts of a solvent. The sound-absorbing layer comprises, by mass fraction: 90-110 parts of TPV thermoplastic elastomer, 3-6 parts of plasticizer, 0.5-1 part of antioxidant, and 20-35 parts of paraffin microcapsules. The barrier layer includes an aluminum foil layer and a polyethylene terephthalate layer, wherein the thickness ratio of the aluminum foil layer to the polyethylene terephthalate layer is 1:(0.1-0.5). The buffer layer is a polyester fiber nonwoven fabric; The sound-absorbing layer has several holes; The sound-absorbing layer has a honeycomb structure, and the honeycomb structure is filled with paraffin microcapsules; The method for preparing the layered composite sound insulation material based on blocking noise propagation paths includes the following steps: (1) The damping layer is prepared by stirring and mixing modified butadiene rubber, modified graphene and damping filler at 60-80℃ for 20-40 min to obtain a damping premix, and then melting and blending at 100-160℃ and extruding to obtain a damping layer. (2) The sound-absorbing layer is prepared by mixing the sound-absorbing filler, the first binder, the flame retardant and the solvent to obtain a slurry, then immersing the substrate containing pores into the slurry for 10-30 seconds, and drying to obtain the sound-absorbing layer. (3) The method for preparing the sound-absorbing layer is to mix TPV thermoplastic elastomer, plasticizer and antioxidant at 160-180℃, and then calender to obtain an elastic substrate. The substrate is then treated with a mold at 170-190℃ and 0.4-0.6MPa for 30-60s to obtain an elastic substrate containing a honeycomb structure. One side of the elastic substrate containing the honeycomb structure has an opening of the honeycomb structure. Paraffin microcapsules are filled into the honeycomb structure through the opening. Then, an elastic film is covered on the side of the elastic substrate containing the honeycomb structure with the opening of the honeycomb structure to obtain the sound-absorbing layer. (4) The barrier layer is prepared by treating the aluminum foil layer and the polyethylene terephthalate layer at 150-170℃ and 0.6-0.8MPa for 3-5 minutes to obtain the barrier layer; (5) The buffer layer, barrier layer, sound-absorbing layer, sound-absorbing layer and damping layer are bonded together layer by layer from bottom to top with the second adhesive, and then pressure is applied for curing to obtain the layered composite sound insulation material; The preparation method of the modified butadiene rubber includes the following steps: S1: Add 1,3-butadiene monomer to a solvent, then add a structure modifier to obtain the first mixed solution; S2: Add an initiator to the first mixed solution to react and obtain polybutadiene with a vinyl content of 45-55%; S3: After the conversion rate of 1,3-butadiene monomer is greater than 96%, a coupling agent is added for coupling, followed by the addition of naphthenic oil for modification, then an antioxidant is added to terminate the reaction, and after dehydration and drying, modified butadiene rubber is obtained. The preparation method of the modified graphene includes the following steps: A1: Mix graphene oxide with a solvent, then add an alkaline solution and stir until homogeneous. Then, perform ultrasonic treatment, centrifuge to collect the supernatant, and dry to obtain alkali-modified graphene oxide. A2: Add silane coupling agent solution to alkali-modified graphene oxide, react at 60-80℃ for 1-2 hours, wash and dry to obtain modified graphene oxide.

2. The layered composite sound insulation material based on noise propagation path blocking according to claim 1, characterized in that, The thickness of the damping layer is 0.3-0.5 mm; The thickness of the sound-absorbing layer is 2-5mm; The thickness of the sound-absorbing layer is 2-3 mm; The thickness of the barrier layer is 0.05-0.1 mm; The thickness of the buffer layer is 1-2 mm.

3. The layered composite sound insulation material based on noise propagation path blocking according to claim 1, characterized in that, The amount of the structure modifier added is 0.1-1% of the mass of the 1,3-butadiene monomer.

4. The layered composite sound insulation material based on noise propagation path blocking according to claim 1, characterized in that, Step A1 includes a reflux treatment step before ultrasound, wherein the reflux treatment step is to reflux at 80-100℃ for 80-100 minutes.

5. The method for preparing a layered composite sound insulation material based on noise propagation path blocking according to any one of claims 1-4, characterized in that, Includes the following steps: (1) The damping layer is prepared by stirring and mixing modified butadiene rubber, modified graphene and damping filler at 60-80℃ for 20-40 min to obtain a damping premix, and then melting and blending at 100-160℃ and extruding to obtain a damping layer. (2) The sound-absorbing layer is prepared by mixing the sound-absorbing filler, the first binder, the flame retardant and the solvent to obtain a slurry, then immersing the substrate containing pores into the slurry for 10-30 seconds, and drying to obtain the sound-absorbing layer. (3) The method for preparing the sound-absorbing layer is to mix TPV thermoplastic elastomer, plasticizer and antioxidant at 160-180℃, and then calender to obtain an elastic substrate. The substrate is then treated with a mold at 170-190℃ and 0.4-0.6MPa for 30-60s to obtain an elastic substrate containing a honeycomb structure. One side of the elastic substrate containing the honeycomb structure has an opening of the honeycomb structure. Paraffin microcapsules are filled into the honeycomb structure through the opening. Then, an elastic film is covered on the side of the elastic substrate containing the honeycomb structure with the opening of the honeycomb structure to obtain the sound-absorbing layer. (4) The barrier layer is prepared by treating the aluminum foil layer and the polyethylene terephthalate layer at 150-170℃ and 0.6-0.8MPa for 3-5 minutes to obtain the barrier layer; (5) The buffer layer, barrier layer, sound-absorbing layer, sound-absorbing layer and damping layer are bonded together layer by layer from bottom to top with the second adhesive, and then pressure is applied for curing to obtain the layered composite sound insulation material.

6. The method for preparing a layered composite sound insulation material based on noise propagation path blocking according to claim 5, characterized in that, The curing temperature of the pressure curing in step (5) is 70-90℃, the pressure is 0.3-0.6MPa, and the curing time is 8-12min.

7. The layered composite sound insulation material based on noise propagation path blocking according to any one of claims 1-4 or the preparation method of the layered composite sound insulation material based on noise propagation path blocking according to any one of claims 5-6 is used in the body, doors, engine compartment and chassis of automobiles.

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