Multi-layer composite structure sound insulation material and preparation method thereof

Abstract

The present invention discloses a multi-layer composite sound insulation material and a preparation method thereof. The material comprises a surface layer and a base layer stacked sequentially, wherein the surface layer is a polyurethane sound-transmitting layer, and the base layer is a polyurethane sound-absorbing layer, which are bonded to each other via an adhesive layer. The present invention employs a multi-layer composite sound insulation material and a preparation method thereof, wherein both layers are polyurethane. The sound-transmitting layer is a polyurethane sound-transmitting elastomer material located on the surface of the composite structure, and the sound-absorbing layer is a composite sound-absorbing material comprising a polyurethane matrix, hollow glass microspheres, and graphene. The number and thickness of the layers are adjustable and can be freely combined. The material exhibits good sound insulation against both low-frequency and medium-high-frequency noise, and the overall structure is lightweight and easy to process.

Description

Technical Field

[0001] The present invention relates to the technical field of sound insulation materials, and in particular to a multi-layer composite structure sound insulation material and a preparation method thereof. Background Art

[0002] Traditional porous sound-absorbing materials have better sound absorption in high-frequency bands, while micro-perforated structures have better sound absorption in low-frequency bands. Single-layer homogeneous materials require increasing the material mass or thickness to enhance their absorption of sound waves of a certain frequency. Polyurethane sound-absorbing materials are a new type of sound-absorbing material. Compared to traditional rubber-based sound-absorbing materials, they offer advantages in terms of vulcanization molding and the characteristic impedance of the material and the water medium, such as adjustable damping and sound absorption properties. They are suitable for absorbing sound waves with a wider frequency band. Existing sound-absorbing structures are mostly composed of two different materials, which can easily separate between layers. There is also the problem of insufficient bonding between the raw materials used to make each layer, which degrades the sound insulation effect during use. Summary of the Invention

[0003] The purpose of the present invention is to provide a multi-layer composite sound insulation material and a preparation method thereof, so as to solve the problem that the sound insulation effect of the above-mentioned sound insulation material is poor due to the easy separation between the layers and the insufficient bonding between the raw materials used in each layer.

[0004] To achieve the above-mentioned object, the present invention provides a multi-layer composite structure sound insulation material, comprising a surface layer and a base layer stacked in sequence, wherein the surface layer is a polyurethane sound-transmitting layer, the base layer is a polyurethane sound-absorbing layer, and the polyurethane sound-transmitting layer and the polyurethane sound-absorbing layer are bonded together by an adhesive layer.

[0005] Preferably, the thickness of the polyurethane sound-transmitting layer is 2-6 mm, and the thickness of the polyurethane sound-absorbing layer is 6-24 mm. The number and thickness of the polyurethane sound-absorbing layer are set according to actual needs.

[0006] Preferably, the polyurethane sound absorbing layer is a composite material of polyurethane material, modified hollow glass microspheres and graphene.

[0007] A method for preparing a multi-layer composite sound insulation material comprises the following steps:

[0008] S1: Preparation of polyurethane sound-transmitting layer: The polyurethane sound-transmitting layer is prepared by reacting a prepolymer and a chain extender;

[0009] S2: Preparation of polyurethane sound absorbing layer: Modified hollow glass microspheres are mixed with graphene and then mixed with polymer polyol. Then, isocyanate, catalyst and chain extender are added to carry out polymerization reaction to form polyurethane sound absorbing layer;

[0010] S3: Bonding the polyurethane sound-transmitting layer and the polyurethane sound-absorbing layer via an adhesive layer to form a sound insulation material.

[0011] Preferably, the specific steps for preparing the polyurethane sound-transmitting layer are as follows:

[0012] S11: Mixing polyester diol, isocyanate, epoxy resin and catalyst, heating to 70-90° C., stirring and reacting for 1-5 hours to obtain a prepolymer;

[0013] S12: heating the prepolymer to 60° C., adding a chain extender, and continuing to heat the prepolymer to 100-150° C., and reacting the prepolymer for 30-60 minutes to obtain a polyurethane sound-transmitting layer.

[0014] Preferably, the polyester diol is a polycarbonate diol with a molecular weight of 500, 1000 or 2000.

[0015] Preferably, the isocyanate in the polyurethane sound-transmitting layer is any one of 4,4'-diisocyanate diphenylmethane, isophorone diisocyanate and toluene diisocyanate.

[0016] Preferably, the specific steps for preparing the polyurethane sound absorbing layer are as follows:

[0017] S21: activating the hollow glass microspheres, and then adding a silane coupling agent KH550 to react to obtain modified hollow glass microspheres having amino groups on the surface;

[0018] S22: mixing the modified hollow glass microspheres and the graphene, stirring, and ultrasonicating to obtain a mixed solution;

[0019] S23: stirring and mixing the mixed solution with the polymer polyol to obtain a functionalized polymer polyol;

[0020] S24: polymerizing the functionalized polymer polyol with isocyanate, a chain extender, and a catalyst at 60-85° C. for 1-2 hours to obtain a polyurethane sound absorbing layer.

[0021] Preferably, the polymer polyol is a polyether polyol having a hydroxyl value of 750 to 800 mgKOH / g and a viscosity of 1500 to 2500 mPa·s at 50° C., specifically polyether polyol NT-403, purchased from Zhejiang Hengfeng Polyurethane Co., Ltd.

[0022] Preferably, the isocyanate in the polyurethane sound absorbing layer is polyphenyl polymethylene polyisocyanate with an average functionality of 2.7-2.8.

[0023] Preferably, the bonding layer in step S3 is an adhesive layer or a hot melt adhesive layer.

[0024] Preferably, the polyurethane sound absorbing layer comprises, by weight, 40-50 parts of polyester diol, 10-15 parts of isocyanate, 3-5 parts of epoxy resin, 0.1-0.6 parts of catalyst, and 1-5 parts of chain extender.

[0025] Preferably, the hollow glass microspheres are acidified with concentrated hydrochloric acid having a mass fraction of 36-38%, ultrasonically washed with deionized water and anhydrous ethanol after 30 minutes, vacuum dried, and then silane coupling agent KH550 is added and stirred under reflux for 24-48 hours to obtain modified hollow glass microspheres;

[0026] The mass ratio of the modified hollow glass microspheres, graphene and polymer polyol is (5-8):(1-3):(30-40);

[0027] The mass ratio of the functionalized polymer polyol, isocyanate, chain extender and catalyst is (35-50):(12-18):(3-5):(0.1-0.5).

[0028] Preferably, the chain extender is ethylene glycol and the catalyst is dibutyltin dilaurate. Chain extenders are small molecule compounds containing multiple isocyanate-reactive groups and are not limited to ethylene glycol. They can also include propylene glycol, butylene glycol, diethylene glycol, and the like. The catalyst is selected from tertiary amine catalysts and metal salt catalysts and is not limited to dibutyltin dilaurate.

[0029] Therefore, the present invention adopts a multi-layer composite sound insulation material with the above structure and a preparation method thereof, which has the following beneficial effects:

[0030] (1) The surface sound-transmitting layer is made of polyurethane sound-transmitting material, whose acoustic impedance matches that of water, which can improve the permeability of sound waves and reduce the reflection of sound waves on the surface of the material; the base sound-absorbing layer is made of polyurethane, hollow glass microspheres and graphene composite materials. Polyurethane material has the advantages of high sound absorption coefficient, low density, adjustable elasticity, convenient and easy curing process, etc. It can effectively solve the technical problem of narrow frequency band of sound-absorbing materials and improve the damping performance and sound absorption performance of different frequency bands.

[0031] (2) Multi-layer composite structure sound insulation material, both layers are made of polyurethane material, the sound-transmitting layer is a polyurethane sound-transmitting elastomer material, located on the surface of the composite structure, and the sound-absorbing layer is a polyurethane matrix with hollow glass microspheres and graphene sound-absorbing materials. The number of layers and thickness can be adjusted and freely combined. It has good sound insulation effect on low-frequency and medium-high-frequency noise, and the overall structure is light and easy to process.

[0032] (3) The present invention simultaneously adds hollow glass microspheres and graphene materials to the polyurethane material to form a base layer, wherein the hollow glass microspheres are specially processed glass microspheres, the interior of which is a rarefied gas, and the main characteristics are that the density is smaller than that of glass microspheres and the thermal conductivity is worse. The main component is borosilicate, and the general particle size is 10 to 250 μm, and the wall thickness is 1 to 2 μm. The hollow glass microspheres have the characteristics of high compressive strength, high melting point, high resistivity, small thermal conductivity and thermal shrinkage coefficient, etc. The hollow glass microspheres have obvious weight reduction and sound insulation and heat preservation effects. The graphene is evenly dispersed in the matrix. When the sound wave is incident on the graphene oxide interface, it will increase the reflection of the sound wave, so that the reflected sound energy increases and the sound propagation path increases, and the sound energy dissipation increases, thereby improving the sound insulation of the material.

[0033] (4) By activating the hollow glass microspheres, the possibility of their surface participating in chemical reactions is increased, making them easier to react with other substances, thereby increasing the compatibility of the hollow glass microspheres with other materials and thereby increasing the service life of the material.

[0034] (5) In the process of preparing the polyurethane sound-absorbing layer, excess silane coupling agent KH550 reacts with the surface of the activated hollow glass microspheres, so that the surface of the modified hollow glass microspheres is connected with amino groups. When mixed with graphene, the amino groups react with active groups such as hydroxyl and carboxyl groups on the surface of graphene. At this time, the modified hollow glass microspheres are bonded to the graphene. When mixed with polymer polyols, the amino groups of the modified hollow glass microspheres, the amino groups on the surface of graphene, and the carboxyl groups on the surface of graphene react with the hydroxyl groups of the polymer polyol. The modified hollow glass microspheres and graphene are simultaneously grafted onto the polymer polyol to form functionalized polymer polyols. Subsequently, as the functionalized polymer polyols undergo polymerization reaction with isocyanate, chain extender and catalyst, the hollow glass microspheres and graphene exist simultaneously in the generated polyurethane, which plays the role of sound insulation for sound waves of different bands, thereby improving the sound insulation performance.

[0035] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic structural diagram of Comparative Example 6;

[0037] Figure 2 is a schematic structural diagram of Example 1;

[0038] Figure 3 It is the sound insulation performance of Example 1 and Comparative Example 6.

[0039] In the figure: 1. Polyurethane sound-transmitting layer; 2. Polyurethane sound-absorbing layer. DETAILED DESCRIPTION

[0040] The present invention will be further described below. It should be noted that this embodiment is based on the technical solution and provides a detailed implementation method and specific operation process, but the present invention is not limited to this embodiment.

[0041] Example 1

[0042] A method for preparing a multi-layer composite sound insulation material comprises the following steps:

[0043] S1: Preparation of polyurethane sound-transmitting layer: The polyurethane sound-transmitting layer is prepared by reacting a prepolymer and a chain extender;

[0044] The specific preparation steps of the polyurethane sound-transmitting layer are as follows:

[0045] S11: Mixing a polyester diol, an isocyanate, an epoxy resin, and a catalyst, raising the temperature to 80° C., and stirring for reaction for 2 hours to obtain a prepolymer, wherein the polyester diol is a polycarbonate diol having a molecular weight of 1000, the isocyanate is 4,4'-diisocyanate diphenylmethane, the chain extender is ethylene glycol, and the catalyst is dibutyltin dilaurate. The polyurethane sound absorbing layer comprises, in parts by weight, 45 parts of the polyester diol, 12 parts of the isocyanate, 4 parts of the epoxy resin, 0.3 parts of the catalyst, and 2 parts of the chain extender;

[0046] S12: The prepolymer is heated to 60° C., a chain extender is added, and the temperature is further raised to 100° C., and the reaction is carried out for 45 minutes to obtain a polyurethane sound-transmitting layer.

[0047] S2: Preparation of polyurethane sound absorbing layer: Modified hollow glass microspheres are mixed with graphene and then mixed with polymer polyol. Then, isocyanate, catalyst and chain extender are added to carry out polymerization reaction to form polyurethane sound absorbing layer;

[0048] The specific preparation steps of the polyurethane sound absorbing layer are as follows:

[0049] S21: The hollow glass microspheres were acidified with concentrated hydrochloric acid having a mass fraction of 36-38%, and then ultrasonically treated for 30 min, washed with deionized water and anhydrous ethanol, and dried in vacuo. Silane coupling agent KH550 was then added and stirred under reflux for 24 hours to obtain modified hollow glass microspheres having amino groups on the surface.

[0050] S22: mixing the modified hollow glass microspheres and the graphene, stirring, and ultrasonicating to obtain a mixed solution;

[0051] S23: stirring and mixing the mixed solution with a polymer polyol to obtain a functionalized polymer polyol, wherein the mass ratio of the modified hollow glass microspheres, the graphene, and the polymer polyol is 5:2:40, wherein the polymer polyol is a polyether polyol having a hydroxyl value of 750 to 800 mgKOH / g and a viscosity of 1500 to 2500 mPa·s at 50° C., specifically polyether polyol NT-403, purchased from Zhejiang Hengfeng Polyurethane Co., Ltd.;

[0052] S24: A functionalized polymer polyol is polymerized with an isocyanate, a chain extender, and a catalyst at 70°C for 1.5 hours to obtain a polyurethane sound-absorbing layer. The mass ratio of the functionalized polymer polyol, isocyanate, chain extender, and catalyst is 45:15:3:0.2. The isocyanate in the polyurethane sound-absorbing layer is polyphenyl polymethylene polyisocyanate with an average functionality of 2.7-2.8, the chain extender is ethylene glycol, and the catalyst is dibutyltin dilaurate.

[0053] S3: bonding the polyurethane sound-transmitting layer and the polyurethane sound-absorbing layer via an adhesive layer to form a sound insulation material, wherein the adhesive layer is a hot-melt adhesive layer.

[0054] A multi-layer composite sound insulation material comprises a top layer and a base layer laminated sequentially. The top layer comprises a polyurethane sound-transmitting layer, while the base layer comprises a polyurethane sound-absorbing layer. The polyurethane sound-transmitting layer and the polyurethane sound-absorbing layer are bonded together via an adhesive layer. Specifically, the polyurethane sound-transmitting layer is 2 mm thick, while the polyurethane sound-absorbing layer is 6 mm thick. The composite structure comprises a polyurethane sound-transmitting layer and two polyurethane sound-absorbing layers bonded sequentially.

[0055] Comparative Example 1

[0056] The difference between Comparative Example 1 and Example 1 is that the hollow glass microspheres were not reacted with the silane coupling agent KH550 after activation, but were directly mixed with graphene. The other steps were the same as those in Example 1.

[0057] Comparative Example 2

[0058] The difference between Comparative Example 2 and Example 1 is that the hollow glass microspheres are not activated to react with the silane coupling agent KH550, but are directly mixed with the graphene. The other steps are the same as those in Example 1.

[0059] Comparative Example 3

[0060] The difference between Comparative Example 3 and Example 1 is that hollow glass microspheres are not added, and the other steps are the same as those of Example 1.

[0061] Comparative Example 4

[0062] The difference between Comparative Example 4 and Example 1 is that no graphene material is added, and the other steps are the same as those of Example 1.

[0063] Comparative Example 5

[0064] The difference between Comparative Example 5 and Example 1 is that the modified hollow glass microspheres and graphene are mixed, stirred and ultrasonicated, and then the mixed solution is directly polymerized with polymer polyol, isocyanate, chain extender and catalyst to obtain a polyurethane sound absorbing layer.

[0065] Comparative Example 6

[0066] Comparative Example 6 differs from Example 1 in that the multilayer composite structure comprises a sequentially laminated surface layer and a base layer, both of which are polyurethane sound-absorbing layers, formed by bonding. Specifically, the polyurethane sound-absorbing layer is 6 mm thick, and the composite structure comprises three sequentially bonded polyurethane sound-absorbing layers.

[0067] The sound insulation properties of the sound insulation materials prepared in Example 1 and Comparative Examples 1-6 were tested.

[0068] Density of polyurethane sound-transmitting layer and polyurethane sound-absorbing layer: Density affects the acoustic characteristic impedance of the material. The acoustic characteristic impedance of polyurethane increases with the increase of density. 3 Within the range, the acoustic characteristic impedance increases from 1.5 to 2.13×10 6 kg / m 2 ·s, the characteristic impedance of water is about 1.45×10 6 kg / m 2 ·s. The density of the sound-transmitting layer in the present invention is 1.02+0.05g / cm 3 , the density of the sound absorbing layer is 1.05+0.05g / cm 3 .

[0069] Figure 1 is a structural diagram of the multilayer composite structure of Comparative Example 6, Figure 2 is a structural diagram of the multilayer composite structure of Example 1, Figure 3 The sound insulation performance between Example 1 and Comparative Example 6 is shown in Table 1. Figure 3 It can be seen that the sound insulation performance of Example 1 is significantly greater than that of Comparative Example 6 at 1000-6000 Hz, and compared with the sound at high frequencies, the effect of Example 1 is better at medium and low frequencies.

[0070] The sound insulation performance of Example 1 and Comparative Examples 1-5 is shown in the table below.

[0071] Table 1 Sound insulation performance test results of Example 1 and Comparative Examples 1-5

[0072]

[0073] Note: The unit of frequency is Hz and the unit of sound transmission loss is dB.

[0074] As can be seen from the table, when no silane coupling agent is added (Comparative Example 1), the connection between the hollow glass microspheres and the graphene material, and between the hollow glass microspheres and the polyurethane material, is relatively weak and unevenly distributed, resulting in a decrease in sound insulation performance. When the hollow microspheres are not activated (Comparative Example 2), the number of reactive groups on the hollow microsphere surface decreases. As an inorganic material, it is difficult for them to physically mix with the polyurethane material and the graphene material, resulting in a decrease in sound insulation performance. When only one of the hollow glass microspheres or the graphene material is added in the present invention (Comparative Examples 3 and 4), the sound insulation performance decreases to varying degrees, indicating that the simultaneous presence of the hollow glass microspheres and the graphene material in the present invention can significantly improve the sound insulation performance of the multilayer composite structure. When the mixture of hollow glass microspheres and graphene is not first mixed with the polymer polyol and then mixed with other raw materials, the sound insulation performance decreases to a certain extent. This shows that mixing the mixture with the polymer polyol first in the present invention can improve the sound insulation performance. This is because some amino and carboxyl groups in the mixture will first react with some hydroxyl groups in the polymer polyol, so that the hollow glass microspheres and graphene material are bonded to the molecular chain of the polymer polyol. On the one hand, the chemical connection between the hollow glass microspheres and graphene material and the polyurethane material is tighter. On the other hand, when the polymer polyol and other raw materials undergo polymerization reaction, the hollow glass microspheres and graphene material are evenly distributed in the polyurethane material. Finally, the hollow glass microspheres and graphene material are spread evenly throughout the entire polyurethane sound-absorbing layer, greatly improving the sound insulation performance.

[0075] Therefore, the present invention adopts a multi-layer composite sound insulation material with the above structure and a preparation method thereof. The multi-layer composite sound insulation material provided by the present invention has two layers made of polyurethane materials, the sound-transmitting layer is a polyurethane sound-transmitting elastomer material, which is located on the surface of the composite structure, and the sound-absorbing layer is a composite sound-absorbing material of a polyurethane matrix, hollow glass microspheres and graphene. The number and thickness of the layers can be adjusted and freely combined. It has good sound insulation effect on both low-frequency and medium-high-frequency noise, and the overall structure is light in weight and easy to process.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a multi-layer composite sound insulation material, characterized by: The multi-layer composite sound insulation material comprises a surface layer and a base layer stacked in sequence, wherein the surface layer is a polyurethane sound-transmitting layer, the base layer is a polyurethane sound-absorbing layer, and the polyurethane sound-transmitting layer and the polyurethane sound-absorbing layer are bonded together by an adhesive layer; Preparation method of multi-layer composite structure sound insulation material The following steps are involved: S1: The specific steps for preparing the polyurethane sound-transmitting layer are as follows: S11: Mixing polyester diol, isocyanate, epoxy resin and catalyst, heating to 70-90° C., stirring and reacting for 1-5 hours to obtain a prepolymer; S12: heating the prepolymer to 60° C., adding a chain extender, and continuing to heat to 100-150° C., reacting for 30-60 minutes to obtain a polyurethane sound-transmitting layer; S2: The specific preparation steps of the polyurethane sound absorbing layer are as follows: S21: activating the hollow glass microspheres, and then adding a silane coupling agent KH550 to react to obtain modified hollow glass microspheres having amino groups on the surface; The hollow glass microspheres were acidified and activated with concentrated hydrochloric acid having a mass fraction of 36-38%, and then washed with deionized water and anhydrous ethanol after ultrasonic treatment for 30 minutes, and then vacuum dried. Then, a silane coupling agent KH550 was added and stirred and refluxed for 24-48 hours to obtain modified hollow glass microspheres. S22: mixing the modified hollow glass microspheres and the graphene, stirring, and ultrasonicating to obtain a mixed solution; S23: stirring and mixing the mixed solution with the polymer polyol to obtain a functionalized polymer polyol; S24: polymerizing the functionalized polymer polyol with isocyanate, a chain extender, and a catalyst at 60-85° C. for 1-2 hours to obtain a polyurethane sound absorbing layer; The mass ratio of the modified hollow glass microspheres, graphene and polymer polyol is (5-8):(1-3):(30-40); The mass ratio of the functionalized polymer polyol, isocyanate, chain extender and catalyst is (35-50):(12-18):(3-5):(0.1-0.5); S3: Bonding the polyurethane sound-transmitting layer and the polyurethane sound-absorbing layer via an adhesive layer to form a sound insulation material.

2. The method for preparing a multi-layer composite sound insulation material according to claim 1, characterized in that: The thickness of the polyurethane sound-transmitting layer is 2-6 mm, and the thickness of the polyurethane sound-absorbing layer is 6-24 mm.

3. The method for preparing a multi-layer composite sound insulation material according to claim 1, characterized in that: The bonding layer in step S3 is an adhesive layer.

4. The method for preparing a multi-layer composite sound insulation material according to claim 1, characterized in that: The polyurethane sound absorbing layer comprises, by weight, 40-50 parts of polyester diol, 10-15 parts of isocyanate, 3-5 parts of epoxy resin, 0.1-0.6 parts of catalyst and 1-5 parts of chain extender.

5. The method for preparing a multi-layer composite sound insulation material according to claim 1, characterized in that: The chain extender is ethylene glycol and the catalyst is dibutyltin dilaurate.

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