Soundproofing waterproof material and preparation method thereof

Abstract

This invention provides a sound-insulating and waterproof material and its preparation method. The sound-insulating and waterproof material includes a composite material and a waterproof material, wherein the waterproof material coats the composite material, and the water contact angle of the waterproof material is >90°. The composite material includes a first composite layer and a second composite layer, with the first composite layer coating the second composite layer. The first composite layer includes lignin fibers, which are obtained by electrospinning lignin and a polymer. The second composite layer includes straw with a particle size of 0.1–1 mm. The sound-insulating and waterproof material provided by this invention, through its specially designed structure, possesses excellent sound insulation and waterproof performance. Furthermore, this invention improves noise pollution by utilizing agricultural waste, which not only conforms to environmental protection principles but also enhances economic benefits.

Description

Technical Field

[0001] This invention belongs to the field of composite materials, and in particular relates to a sound-insulating and waterproof material and its preparation method. Background Technology

[0002] Noise is a continuous or sudden sound that can impair the physical functions or emotions of an organism. From a physical perspective, noise is the sound produced when a sound-producing body vibrates irregularly; from an environmental protection perspective, any sound that interferes with human work, life, or study is called noise.

[0003] Noise pollution has become a global environmental problem, ranking alongside air pollution, water pollution, and solid waste pollution as one of the world's four major pollutions. With economic and technological development, agriculture and industry are becoming increasingly mechanized, and transportation is booming. However, noise pollution is also becoming increasingly severe. Especially in economically developed, densely populated large and medium-sized cities, noise pollution has significantly impacted people's lives. Prolonged exposure to noise can seriously damage the auditory system, leading to symptoms such as dizziness, tinnitus, and hearing loss. Noise pollution also accelerates the aging of buildings and mechanical structures. Sound insulation materials can dissipate sound energy during sound wave propagation, thus reducing noise. Therefore, modern society has an increasing demand for sound insulation materials, and the performance requirements for these materials are also becoming more stringent. On the other hand, moisture or water accumulation can damage sound insulation materials and cause other problems such as mold and corrosion. Therefore, it is also necessary to improve the waterproof performance of sound insulation materials. Summary of the Invention

[0004] In order to improve the sound insulation performance and waterproof performance of sound insulation materials, this invention provides a sound insulation and waterproof material and its preparation method.

[0005] According to one aspect of the present invention, a sound-insulating and waterproof material is provided, the sound-insulating and waterproof material comprising a composite material and a waterproof material, wherein the waterproof material coats the composite material and the water contact angle of the waterproof material is >90°; wherein the composite material comprises a first composite layer and a second composite layer, the first composite layer coating the second composite layer, wherein the first composite layer comprises lignin fiber, the lignin fiber being obtained by electrospinning lignin and a polymer; the second composite layer comprises straw, the straw having a particle size of 0.1–1 mm.

[0006] Existing technologies generally use electrospinning to mix waterproof materials with lignin to directly prepare nanomaterials.

[0007] The electrospinning solution used in traditional fiber-repellent materials, due to its complex solute composition, leads to coarser fibers and increased beading, affecting the sound insulation performance of the fibers. This invention first combines lignin fibers with straw, enhancing the sound insulation and mechanical properties of the composite material. This is because straw of appropriate particle size provides the composite material with more porous structures, not only serving as a support for the lignin fibers and providing mechanical properties, but also dissipating sound energy during sound wave propagation. Subsequently, a waterproof material is coated onto the composite material, providing waterproofing and improving the bonding between the lignin fibers and straw, thereby enhancing the mechanical and sound insulation properties of the composite material. Therefore, the sound-insulating and waterproof material provided by this invention has excellent sound insulation and waterproofing performance, and by utilizing agricultural waste to mitigate noise pollution, it not only aligns with environmental protection principles but also improves economic benefits.

[0008] Preferably, the polymer includes at least one of polylactic acid and polyacrylonitrile. Electrospinning is a spinning process that uses a solvent to dissolve the polymer, and then applies a high-voltage electrostatic field to stretch the polymer into filaments through the interaction of positive and negative voltages. This invention combines lignin with a polymer to uniformly stretch lignin into filaments. In the spinning solution, different polymer systems affect the solution viscosity, which in turn affects the fiber structure.

[0009] Preferably, the waterproof material includes at least one of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and fluorinated polyurethane (FPU).

[0010] Preferably, the ratio of composite material to waterproof material is calculated as 1:0.05 to 0.5 based on the thickness ratio.

[0011] Preferably, the ratio of the first composite layer to the second composite layer is calculated as 1:1 to 3 based on the thickness ratio.

[0012] Preferably, the thickness of the lignin fiber is 5 to 30 mm.

[0013] Preferably, the average diameter of the lignin fibers is 0.05 to 1.5 μm.

[0014] Preferably, the second composite layer further includes a polymer. The polymer can further improve the adhesion between the straw and the lignin fibers.

[0015] In a second aspect, the present invention provides a method for preparing the sound-insulating and waterproof material as described above, the method comprising the following steps: S1. preparing a first reaction solution by mixing lignin, a polymer, and a solvent, and then obtaining lignin fibers by electrospinning the first reaction solution; S2. immersing the lignin fibers in a straw solution and drying them to obtain a composite material; S3. immersing the composite material in a waterproof material solution and then allowing it to stand and drying to obtain the sound-insulating and waterproof material.

[0016] Preferably, the solvent includes at least one of dichloromethane, N,N-dimethylformamide, N,N-dimethylacetamide, formic acid, acetic acid, acetone, chloroform, toluene, xylene, and dimethyl sulfoxide.

[0017] Preferably, in the first reaction solution, the mass ratio of lignin to polymer is 1 to 3:1.

[0018] Preferably, the mass concentration of the first reaction solution is 15-30%.

[0019] Preferably, in S2 to S3, the drying temperature is freeze drying.

[0020] Preferably, in step S2, the process of immersing lignin fibers in a straw solution followed by freeze-drying is repeated 3 to 5 times.

[0021] Preferably, in step S3, the process of immersing the composite material in a waterproof material solution and then freeze-drying it is repeated 2 to 4 times. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0023] Example 1

[0024] 1. Prepare the raw materials

[0025] The raw materials used to prepare the sound insulation and waterproof material are shown in Table 1. In this embodiment, the raw materials are prepared according to the table.

[0026] Table 1. Raw materials required for preparing sound-insulating and waterproof materials in Example 1

[0027]

[0028] 2. Preparation method

[0029] S1. A first reaction solution is prepared by mixing lignin, polylactic acid, and N,N-dimethylacetamide (DMAC), wherein the mass concentration of the first reaction solution is 15%, and the mass ratio of lignin to polylactic acid is 2:1; then the first reaction solution is used to obtain lignin fibers by electrospinning.

[0030] S2. Disperse straw in N,N-dimethylformamide (DMF) to obtain a straw solution. Then, lignin fibers are immersed in the straw solution, allowed to stand for 60 minutes, and then freeze-dried. Repeat the above operation 3 times to obtain the composite material.

[0031] S3. The composite material is then immersed in water-based fluorinated polyurethane, left to stand for 20 minutes, and then freeze-dried. The above operation is repeated twice to obtain the sound-insulating and waterproof material.

[0032] In this embodiment, the lignin fiber has a thickness of 15 mm and an average diameter of 2.2 μm; in the prepared sound insulation and waterproof material, and calculated according to the thickness ratio, the ratio of the first composite layer to the second composite layer is 1:1.5, and the ratio of the composite material to the waterproof material is 1:0.1.

[0033] Example 2

[0034] This embodiment refers to the formula and method provided in Embodiment 1 to prepare sound-insulating and waterproof materials. The difference from Embodiment 1 is that the straw used in this embodiment has a particle size of 0.1 mm when preparing the sound-insulating and waterproof materials. Apart from the above differences, the operation steps for preparing the sound-insulating and waterproof materials in this embodiment are strictly consistent with those in Embodiment 1.

[0035] Example 3

[0036] This embodiment refers to the formula and method provided in Embodiment 1 to prepare sound insulation and waterproof material. The difference from Embodiment 1 is that in this embodiment, polyacrylonitrile is replaced with an equal mass fraction of polylactic acid when preparing the sound insulation and waterproof material. Apart from the above differences, the operation steps for preparing the sound insulation and waterproof material in this embodiment are strictly consistent with those in Embodiment 1.

[0037] Example 4

[0038] This embodiment refers to the formula and method provided in Embodiment 1 to prepare sound-insulating and waterproof materials. The difference from Embodiment 1 is that, in this embodiment, the sound-insulating and waterproof materials are prepared with a thickness ratio of composite material to waterproof material of 1:0.05. In this embodiment, the thickness ratio is changed by altering the concentration of the fluorinated polyurethane solution in S3. Apart from the above differences, the operation steps for preparing the sound-insulating and waterproof materials in this embodiment are strictly consistent with those in Embodiment 1.

[0039] Example 5

[0040] This embodiment refers to the formula and method provided in Embodiment 1 to prepare sound-insulating and waterproof materials. The difference from Embodiment 1 is that, in this embodiment, the sound-insulating and waterproof materials are prepared with a thickness ratio of composite material to waterproof material of 1:0.8. In this embodiment, the thickness ratio is changed by altering the concentration of the fluorinated polyurethane solution in S3 and the number of repetitions. Apart from the above differences, the operation steps for preparing the sound-insulating and waterproof materials in this embodiment are strictly consistent with those in Embodiment 1.

[0041] Example 6

[0042] This embodiment refers to the formula and method provided in Embodiment 1 to prepare sound-insulating and waterproof materials. The difference from Embodiment 1 is that, in this embodiment, the sound-insulating and waterproof materials are prepared with a thickness ratio of 1:1 for the first composite layer and the second composite layer. In this embodiment, the change in thickness ratio is achieved by changing the concentration of the straw solution in S2. Apart from the above differences, the operation steps for preparing the sound-insulating and waterproof materials in this embodiment are strictly consistent with those in Embodiment 1.

[0043] Example 7

[0044] This embodiment refers to the formula and method provided in Embodiment 1 to prepare sound-insulating and waterproof materials. The difference from Embodiment 1 is that, in this embodiment, the sound-insulating and waterproof materials are prepared with a thickness ratio of 1:4 for the first composite layer and the second composite layer. In this embodiment, the thickness ratio is changed by altering the concentration of the straw solution in S2 and the number of repetitions. Apart from the above differences, the operation steps for preparing the sound-insulating and waterproof materials in this embodiment are strictly consistent with those in Embodiment 1.

[0045] Example 8

[0046] This embodiment refers to the formula and method provided in Embodiment 1 to prepare sound insulation and waterproof material. The difference from Embodiment 1 is that in the process of preparing the sound insulation and waterproof material in this embodiment, the drying treatment in steps S2 to S3 is vacuum drying at 80°C for 24 hours. Apart from the above differences, the operation steps for preparing the sound insulation and waterproof material in this embodiment are strictly consistent with those in Embodiment 1.

[0047] Comparative Example 1

[0048] This comparative example prepares sound-insulating and waterproof materials according to the formula and method provided in Example 1. The difference between this comparative example and Example 1 is that the second composite layer is not provided in the preparation of the sound-insulating and waterproof materials (i.e., step S2 is omitted). Apart from the above differences, the operation steps for preparing the sound-insulating and waterproof materials in this comparative example are strictly consistent with those in Example 1. Specifically, the operation steps for preparing the sound-insulating and waterproof materials in this comparative example are as follows:

[0049] S1. Strictly follow the method provided in Example 1;

[0050] S2. Prepare a 15% fluorinated polyurethane solution using N,N-dimethylacetamide as a solvent, then immerse the obtained lignin fibers in the fluorinated polyurethane solution and freeze-dry them. Repeat the above operation twice to obtain a sound-insulating and waterproof material.

[0051] Comparative Example 2

[0052] This comparative example prepares sound-insulating and waterproof materials according to the formula and method provided in Example 1. The difference between this comparative example and Example 1 is that the straw used in preparing the sound-insulating and waterproof materials has a particle size of 2 mm. Apart from the above differences, the operation steps for preparing the sound-insulating and waterproof materials in this comparative example are strictly consistent with those in Example 1.

[0053] Comparative Example 3

[0054] This comparative example prepares sound-insulating and waterproof materials according to the formula and method provided in Example 1. The difference between this comparative example and Example 1 is that no polymer is added to prepare lignin fibers during the preparation of the sound-insulating and waterproof materials. Apart from the above differences, the operational steps for preparing the sound-insulating and waterproof materials in this comparative example are strictly consistent with those in Example 1. Specifically, the operational steps for preparing the sound-insulating and waterproof materials in this comparative example are as follows:

[0055] S1. A first reaction solution is prepared by mixing lignin and N,N-dimethylacetamide, wherein the mass concentration of the first reaction solution is 15%; then, lignin fibers are obtained by electrospinning the first reaction solution.

[0056] S2~S3. Strictly follow the preparation method provided in Example 1.

[0057] Comparative Example 4

[0058] This comparative example prepares sound-insulating and waterproof materials according to the formula and method provided in Example 1. The difference between this comparative example and Example 1 is that, in preparing the sound-insulating and waterproof materials, lignin, polylactic acid, straw, and waterproof materials are mixed and prepared by electrospinning. Apart from the above differences, the operation steps for preparing the sound-insulating and waterproof materials in this comparative example are strictly consistent with those in Example 1.

[0059] Specifically, the operation steps for preparing the sound-insulating and waterproof material in this comparative example are as follows: a reaction solution is prepared by mixing lignin, polylactic acid, straw, fluorinated polyurethane, and N,N-dimethylacetamide, wherein the mass concentration of the reaction solution is 20%, and the sound-insulating and waterproof material is obtained by electrospinning.

[0060] Comparative Example 5

[0061] This comparative example prepares sound-insulating and waterproof materials according to the formula and method provided in Example 1. The difference from Example 1 is that in this comparative example, lignin, polylactic acid, and straw are mixed and electrospun to prepare a composite material. Apart from the above differences, the operational steps for preparing the sound-insulating and waterproof materials in this comparative example are strictly consistent with those in Example 1. Specifically, the operational steps for preparing the sound-insulating and waterproof materials in this comparative example are as follows:

[0062] S1. A reaction solution is prepared by mixing lignin, straw, polylactic acid, and N,N-dimethylacetamide, wherein the mass concentration of the reaction solution is 15%, and the mass ratio of lignin:straw:polylactic acid is 2:2:1; then the reaction solution is used to prepare a composite material by electrospinning.

[0063] S2. Strictly follow S3 in Example 1.

[0064] Test case

[0065] 1. Test Object

[0066] Waterproof and soundproof materials prepared in Examples 1-8 and Comparative Examples 1-5.

[0067] 2. Testing Methods

[0068] 1. Sound Insulation Test: The vertical incident sound absorption rate of the test object was measured using a vertical incident sound absorption rate measuring device within the frequency range of 500–3000 Hz. It was found that the transmission loss of the composite material increased with increasing frequency.

[0069] ① The average absorption rate (α) represents the sound absorption performance in the frequency range of 500Hz to 1000Hz. The higher the value, the higher the sound absorption. When α is above 0.23, the sound absorption in the low-frequency region is evaluated as good and represented by "O"; when it is less than 0.23, the sound absorption is evaluated as poor and represented by "X".

[0070] ② The average absorption rate (β) represents the sound absorption performance in the frequency range of 1000Hz to 3000Hz. The higher the value, the higher the sound absorption. When β is above 0.60, the sound absorption in the mid-frequency range is evaluated as good and represented by "O"; when it is less than 0.60, the sound absorption is evaluated as poor and represented by "X".

[0071] 2. Waterproof test: Weigh the test object to obtain its mass m0. Then fix the test object on a glass plate and spray 150mL of water evenly on the surface of the test object. Shake off the water droplets attached to the sample and weigh it m. The formula for calculating the water absorption rate of the sample is: water absorption rate = (m-m0) / m0×100%. The lower the water absorption rate, the better its waterproof performance, and vice versa.

[0072] 3. Test Results and Analysis

[0073] The test results for this test example are shown in Table 2. In Comparative Example 1, the lack of a second composite layer in the sound-insulating and waterproof material resulted in a significant decrease in its sound absorption performance in the 1000Hz–3000Hz frequency range. Combining Examples 1–2 and Comparative Example 2, it can be observed that the particle size of the straw affects both the sound-insulating and waterproof properties of the material. Specifically, a straw particle size of 0.1–1 mm provides both good sound insulation and waterproof performance.

[0074] Based on the data from Examples 1, 3, and Comparative Example 3, introducing polymers during the preparation of lignin fibers significantly improves their toughness, thereby imparting good porosity and enhancing their sound insulation properties. Furthermore, the selection of different polymers also affects the waterproof performance of the sound-insulating and waterproofing materials.

[0075] In Examples 1 and 4-5, it was found that changing the thickness ratio between the composite material and the waterproof material affects the sound insulation and waterproofing performance of the sound-insulating and waterproofing material. This is because when the composite material and the waterproof material maintain a certain thickness ratio, the sound-insulating and waterproofing material can maintain a better porosity, thereby improving the sound insulation performance. Furthermore, tests showed that a thicker waterproofing material does not necessarily result in better waterproofing performance. Comparing the test data from Examples 1 and 6-7 revealed that changing the thickness ratio between the first composite layer and the second composite layer also affects the sound insulation and waterproofing performance of the sound-insulating and waterproofing material.

[0076] In Examples 1 and 8, by changing the drying process in steps S2 to S3 of the preparation method, it was found that the drying process affects the pore structure of the sound-insulating and waterproof material. Compared with Example 1, the sound-insulating and waterproof material prepared by vacuum drying in Example 8 has reduced pore size. Although it still maintains good sound insulation performance, the sound insulation performance of Example 8 is slightly worse than that of Example 1.

[0077] In Comparative Example 4, a sound-insulating and waterproof material was prepared by electrospinning a mixture of lignin, polylactic acid, straw, and waterproofing materials. Compared to Example 1, the increased relative molecular mass of the reaction solution in Comparative Example 4 led to increased surface tension and viscosity, which in turn altered the morphology of the electrospun fibers. Consequently, the waterproofing and sound-insulating properties of the material prepared in Comparative Example 4 significantly decreased. In Comparative Example 5, a composite material was prepared by electrospinning a mixture of lignin, polylactic acid, and straw. However, the larger particle size of the straw also caused changes in the morphology of the spun fibers, resulting in a decrease in sound insulation performance.

[0078] Table 2. Test results for this test case

[0079]

[0080] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A sound-insulating and waterproof material, characterized in that, The sound insulation and waterproofing material includes a composite material and a waterproofing material, wherein the waterproofing material coats the composite material, and the waterproofing material is at least one of polytetrafluoroethylene, polyvinylidene fluoride, and fluorinated polyurethane. The composite material includes a first composite layer and a second composite layer, wherein the first composite layer covers the second composite layer; The first composite layer is lignin fiber, which is obtained by electrospinning lignin and a polymer; the polymer is at least one of polylactic acid and polyacrylonitrile. The second composite layer includes straw, wherein the straw has a particle size of 0.1 to 1 mm; The method for preparing the sound-insulating and waterproof material includes the following steps: S1. A first reaction solution is prepared by mixing the lignin, the polymer, and the solvent, and then the lignin fiber is obtained by electrospinning the first reaction solution. S2. The lignin fiber is immersed in a solution containing the straw and then dried to obtain a composite material; S3. The composite material is immersed in a solution containing the waterproof material, and after standing and drying, the sound-insulating and waterproof material is obtained.

2. The soundproof and waterproof material as described in claim 1, characterized in that, Based on the thickness ratio, the ratio of the composite material to the waterproof material is 1:0.05 to 0.

5.

3. The soundproof and waterproof material as described in claim 2, characterized in that, Based on the thickness ratio, the ratio of the first composite layer to the second composite layer is 1:1 to 3.

4. The soundproof and waterproof material as described in claim 3, characterized in that, The thickness of the lignin fiber is 5–30 mm.

5. The soundproof and waterproof material as described in claim 4, characterized in that, The lignin fibers have an average diameter of 0.5–3 μm.

6. The sound-insulating and waterproof material as described in claim 1, characterized in that, In the first reaction solution, the ratio of lignin to polymer is calculated to be 1 to 3:1 by mass.

7. The soundproof and waterproof material as described in claim 1, characterized in that, In S2 to S3, the drying process is freeze drying.

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