A medium-high frequency sound-absorbing noise-reducing lightweight organic silicon coating and application thereof

Abstract

The present application relates to a kind of medium-high frequency sound absorption noise reduction light weight organic silicon coating and its application, coating includes the following components and weight content: vinyl silicone oil 50~51 parts, hydrogen-containing silicone oil 0.5~0.6 parts, inhibitor 0.01~2 parts, platinum catalyst 0.05~0.5 parts, fumed silica 3~12 parts, silica aerogel 1~1.1 parts, polyacrylonitrile short-cut fiber 5~20 parts.Compared with prior art, the coating prepared in the present application has the advantages of wide frequency and wide temperature range sound absorption, sound insulation and flame retardant, etc., can be applied to medium-high frequency sound absorption noise reduction scene, especially used as sound absorption noise reduction coating for new energy vehicle electric drive system, sound absorption noise reduction coating for the inner side of aircraft skin, sound absorption noise reduction coating for the inner side of rail train skin and sound absorption noise reduction coating for the inner side of deep-sea warship, etc., with the advantages of low cost, simple preparation method, good sound insulation effect, etc.

Description

Technical Field

[0001] This invention belongs to the fields of new energy vehicles, construction, and marine vessels, and relates to a medium- and high-frequency sound-absorbing and noise-reducing lightweight organosilicon coating and its application. Background Technology

[0002] As the driving range of new energy vehicles continues to increase and the demand for spacious and comfortable rides grows, the expansion of battery capacity and the increase in passenger space have reduced the space available for electric drive transmissions. Traditional passive NVH shielding solutions for new energy vehicle transmissions involve acoustically encapsulating the electric drive assembly, such as a multi-layered material (e.g., polyurethane foam, polyester fiber, or aerogel) or a 20 mm thick polypropylene and polyester fiber two-component sound-absorbing cotton (PP / PET) and a 2 mm thick sound insulation board (EPDM rubber), which can typically reduce noise by more than 10 dB. However, traditional solutions require approximately 20-30 mm of space, which is insufficient to meet the vibration and noise reduction requirements of the new electric drive assembly after space compression. Sound absorption and noise reduction for new energy vehicle electric drive assemblies are evolving from traditional "passive encapsulation" to active integrated coatings. For example, Henkel's Teroson series noise-reducing coating, based on water-based acrylic, is a hard-elastic coating specifically designed to suppress structurally conducted noise. It must be combined with other structural reinforcements and multi-media sound insulation for systematic acoustic shielding. BASF's Acronal series, based on high-performance acrylic emulsions, is specifically designed for vibration damping in the 200-1500Hz range. Patent CN114479584B provides a sound-insulating, heat-preserving, and flame-retardant water-based damping coating using inorganic minerals as fillers, resulting in a high overall coating density, which is detrimental to weight reduction in new energy vehicles. Patent CN119955363B provides a modified hydrophobic calcium silicate aerogel micropowder as a filler for water-based damping coatings in new energy vehicles, effectively reducing coating density. However, the effective damping temperature range of acrylic resin is narrow (typically 20-30℃), and damping performance rapidly declines above 80℃, making it difficult to meet the drastic temperature changes (-40℃ to 120℃) of electric drive systems from cold start to high-speed operation. Currently, there is no coating solution that meets the requirements for mid-to-high frequency lightweight sound absorption and noise reduction in new energy electric drive assemblies. Summary of the Invention

[0003] The purpose of this invention is to provide a lightweight organosilicon coating and its application in mid-to-high frequency sound-absorbing and noise-reducing coatings. The coating prepared from the lightweight organosilicon coating of this invention possesses excellent comprehensive properties such as wide-frequency and wide-temperature-range sound absorption, sound insulation, and flame retardancy. It is suitable for mid-to-high frequency sound absorption and noise reduction scenarios, especially as a sound-absorbing and noise-reducing coating for electric drive systems of new energy vehicles, the inner skin of aircraft, the inner skin of rail trains, or the inner surface of deep-sea vessels. It has advantages such as low cost, simple preparation method, and good sound insulation effect.

[0004] The objective of this invention can be achieved through the following technical solutions: A first aspect of the present invention provides a lightweight organosilicon coating comprising the following components and their weight percentages: 50-51 parts of vinyl silicone oil Hydrogen-containing silicone oil, 0.5~0.6 parts, Inhibitor 0.01~2 parts, Platinum catalyst 0.05~0.5 parts, 3-12 parts of fumed silica 1-1.1 parts of silica aerogel 5-20 parts of short-cut polyacrylonitrile fibers.

[0005] In some specific embodiments, the vinyl silicone oil is selected from terminal vinyl silicone oils or side-chain high-vinyl silicone oils, with a vinyl content of 0.32%. 0.02 wt%, viscosity of 900 ~ 1100 cP; the hydrogen-containing silicone oil is selected from low-hydrogen silicone oil with a hydrogen content of 0.5 ~ 0.6 wt%; the inhibitor is selected from ethynylcycloethanol or methylbutynol; the platinum catalyst is selected from Karstedt catalyst, the main component of which is platinum(O)-divinyltetramethyldisiloxane complex.

[0006] In some specific embodiments, the fumed silica is selected from hydrophobic fumed silica with a specific surface area of ​​90~130 m². 2 / g; the specific surface area of ​​the silica aerogel is 400~700 m² / g. 2 / g.

[0007] In some specific embodiments, the average length of the chopped polyacrylonitrile fibers is 2 to 5 mm and the average diameter is 10 to 30 μm.

[0008] A second aspect of the present invention provides an application of the lightweight silicone coating as described above, including using the lightweight silicone coating to prepare a sound-absorbing, noise-reducing, and flame-retardant coating.

[0009] In some specific embodiments, the sound-absorbing, noise-reducing, and flame-retardant coating is used as a sound-absorbing and noise-reducing coating for electric drive systems of new energy vehicles, a sound-absorbing and noise-reducing coating on the inner side of aircraft skin, a sound-absorbing and noise-reducing coating on the inner side of rail train skin, or a sound-absorbing and noise-reducing coating on the inner side of deep-sea ships.

[0010] In some specific embodiments, the method for preparing the sound-absorbing, noise-reducing, and flame-retardant coating includes: Vinyl silicone oil, hydrogen-containing silicone oil, inhibitor, platinum catalyst, fumed silica, and silica aerogel are mixed and prepared into a first raw material liquid; a second raw material liquid containing short-cut polyacrylonitrile fibers is mixed with the first raw material liquid, coated, and heated and cured at 100~150℃ to obtain the sound-absorbing, noise-reducing, and flame-retardant coating.

[0011] In some specific embodiments, the solvents used in the first and second raw material liquids are selected from highly volatile non-polar solvents such as aviation 120 solvent oil, toluene, or xylene.

[0012] In some specific embodiments, the preparation of the first raw material liquid and the second raw material liquid is carried out at room temperature.

[0013] In some specific embodiments, the preparation method of the first raw material liquid includes: first adding vinyl silicone oil, hydrogen-containing silicone oil and inhibitor to a solvent, then adding platinum catalyst and mixing evenly, and then adding fumed silica and silica aerogel to obtain the solution.

[0014] In some specific embodiments, the sound-absorbing, noise-reducing, and flame-retardant coating includes a bottom layer and a top layer; The top layer is made of the aforementioned lightweight organosilicon coating or silicone coating; the silicone coating comprises the following components and their weight percentages: 50 parts of component A of LK1500-28 silicone, 50 parts of component B of LK1500-28 silicone, and 50 parts of barium sulfate; the barium sulfate has a particle size of 2 ~ 10 μm. The bottom layer is made using the aforementioned lightweight organosilicon coating.

[0015] In some specific embodiments, the method for preparing the top or bottom layer of the lightweight organosilicon coating includes: Vinyl silicone oil, hydrogen-containing silicone oil, inhibitor, platinum catalyst, fumed silica, and silica aerogel are mixed and prepared into a first raw material liquid; a second raw material liquid containing short-cut polyacrylonitrile fibers is mixed with the first raw material liquid, coated, and heated and cured at 100~150℃ to obtain the sound-absorbing, noise-reducing, and flame-retardant coating.

[0016] In some specific embodiments, the method for preparing the top layer of the silicone coating includes: 45-55 wt% of barium sulfate is mixed with component A of LK1500-28 silicone to obtain a first mixture; the remaining barium sulfate is mixed with component B of LK1500-28 silicone to obtain a second mixture; the first mixture and the second mixture are mixed, coated onto a substrate, and cured at room temperature to obtain the final product.

[0017] In some specific embodiments, the raw materials are uniformly mixed by a vacuum rotary mixer during the preparation of the first and second mixtures.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1) The sound absorption and noise reduction coating of the medium and high frequency sound absorption coating of the new energy electric drive system has a stable sound absorption and noise reduction effect in a wide temperature range of -60℃ to 120℃. The sound absorption coefficient is above 0.9 in the range of 1000-6000Hz and the sound loss is above 16 dB. 2) The coating thickness is controlled at 5-6 mm. The primer / topcoat composite coating has a significantly better sound absorption and noise reduction effect in the mid-to-high frequency range than the 20-30 mm two-component sound-absorbing cotton and sound insulation layer in the traditional technical solution (Comparative Example 1), while the effect of a single primer coating is comparable to the latter. The coating can significantly reduce the space occupied by the electric drive assembly in the chassis. Attached Figure Description

[0019] Figure 1 The following are the sound loss at 1000-6500 Hz, sound loss at 250-1600 Hz, sound absorption coefficient at 1000-6500 Hz, and sound absorption coefficient at 250-1600 Hz of a lightweight coating for mid-to-high frequency sound absorption and noise reduction used in new energy vehicles prepared in Examples 1-4. Figure 2 (a) is an optical photograph of a lightweight coating sample for mid-to-high frequency sound absorption and noise reduction used in new energy vehicles prepared in Example 1 and (b) Example 5; Figure 3 Optical photographs of a coating sample prepared in Comparative Example 1 and Comparative Example 2: Comparative Example 1 (a) front view, (b) side view, Comparative Example 2 (c) front view, (d) side view; Figure 4 This is a cross-sectional microstructure diagram of a lightweight, mid-to-high frequency sound-absorbing and noise-reducing coating (primer) for new energy vehicles prepared in Example 1. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0021] The following are more detailed implementation examples, which further illustrate the technical solution of the present invention and the technical effects that can be obtained.

[0022] In the following embodiments, unless otherwise specified, the raw materials, reagents, or processing techniques are all conventional commercial products or conventional processing techniques in the art, including processing at room temperature, processing at atmospheric pressure, and processing in air atmosphere.

[0023] Vinyl silicone oil, purchased from Zhenjiang Jusheng New Energy Co., Ltd., model: JSV1000, vinyl content: 0.32%. 0.02 wt%, viscosity 900 ~ 1100 cP; Hydrogen-containing silicone oil, purchased from Zhenjiang Jusheng New Energy Co., Ltd., model: JSH050, hydrogen content: 0.5 wt%; Inhibitor, purchased from Zhenjiang Jusheng New Energy Co., Ltd., ethynylcyclohexanol; Platinum catalyst, purchased from Zhenjiang Jusheng New Energy Co., Ltd., Karsted platinum catalyst, 2000 ppm; Fumed silica, purchased from Evonik, model: Aerosil® R 972, features: hydrophobic, specific surface area 110. 20 m 2 / g; Silica aerogel, purchased from Jiazhiqi New Materials Co., Ltd., model: 811, specific surface area: 500-600 m² 2 / g, 400-700 m 2 / g; The short-cut polyacrylonitrile fibers were purchased from Daitian Engineering Materials Co., Ltd., with an average fiber diameter of 10 ~ 15 μm and an average fiber length of 3 mm. Aviation 120 solvent oil, purchased from Zhengxin Chemical Technology Co., Ltd., model: 120# aviation solvent oil; LK1500-28 silicone, purchased from Dongguan Xinkang Organosilicon Materials Co., Ltd., model LK1500-28; 2μm barium sulfate, brand: Aladdin, item number: B112377-1kg.

[0024] Example 1 In this embodiment, the raw materials and weight ratio of the sound-absorbing, noise-reducing, and flame-retardant lightweight organosilicon coating are as follows: Vinyl silicone oil 50.5 g, hydrogen-containing silicone oil 0.6 g, inhibitor 0.02 g, platinum catalyst 0.11 g, fumed silica 10.3 g, 500-600m 2 / g silica aerogel 1.1 g, 2-3 mm polyacrylonitrile short-cut fibers 10.3 g. Solvent: aviation 120# solvent oil 126.1 g.

[0025] Coating preparation method: (1) At room temperature, 10.3 g of polyacrylonitrile short-cut fibers were soaked in 72.3 g of aviation 120# solvent oil for about 0.5 hours and then stirred evenly; (2) Weigh 50.5 g of vinyl silicone oil, 0.6 g of hydrogen-containing silicone oil and 0.02 g of inhibitor and add them to 53.8 g of aviation 120# solvent oil and mix evenly. Then add 0.11 g of platinum catalyst and mix evenly. (3) Weigh 10.3 g of fumed silica and 1.1 g of silica aerogel in sequence, and add them to the organosilicon slurry prepared in step (2), and stir evenly; (4) Add the short-cut polyacrylonitrile fibers impregnated in step (1) and the solvent to the slurry prepared in step (3), and mix them evenly by mechanical stirring to obtain the slurry for sound-absorbing and noise-reducing coating. (5) The slurry prepared in step (4) is manually applied to polytetrafluoroethylene molds with diameters of 30 mm and 100 mm, and cured at 120°C for 3 hours to form a coating with a gradient distribution of nano- and micron-sized pores. The average density of the coating is 0.47 g / cm³. 3 The thickness is ~ 5.7 mm.

[0026] Example 2 In this embodiment, the raw materials and weight ratio of the sound-absorbing, noise-reducing, and flame-retardant lightweight organosilicon coating are as follows: Vinyl silicone oil 50.94 g, hydrogen-containing silicone oil 0.54 g, inhibitor 0.03 g, platinum catalyst 0.11 g, fumed silica 10.07 g, 500-600m 2 / g silica aerogel 1.26 g, 3 mm polyacrylonitrile short-cut fibers 5.04 g. Solvent: aviation 120# solvent oil 100.5 g.

[0027] Coating preparation method: (1) At room temperature, 5.04 g of polyacrylonitrile short-cut fibers were soaked in 50.1 g of aviation 120# solvent oil for about 0.5 hours and then stirred evenly.

[0028] (2) Weigh 50.94 g of vinyl silicone oil, 0.54 g of hydrogen-containing silicone oil and 0.03 g of inhibitor and add them to 50.4 g of aviation 120# solvent oil and mix evenly. Then add 0.11 g of platinum catalyst and mix evenly.

[0029] (3) Weigh 10.07 g of fumed silica and 1.26 g of silica aerogel in sequence, and add them to the organosilicon slurry prepared in step (2), and stir evenly.

[0030] (4) Add the polyacrylonitrile short-cut fibers impregnated in step (1) and solvent to the slurry prepared in step (3), and mix them evenly by mechanical stirring to obtain the slurry for sound-absorbing and noise-reducing coating.

[0031] (5) The slurry prepared in step (4) is manually applied to polytetrafluoroethylene molds with diameters of 30 mm and 100 mm, and cured at 120°C for 3 hours to form a coating with a gradient distribution of nano- and micron-sized pores. The average density of the coating is 0.61 g / cm³. 3 The thickness is ~4.7 mm.

[0032] Example 3 In this embodiment, the raw materials and weight ratio of the sound-absorbing, noise-reducing, and flame-retardant lightweight organosilicon coating are as follows: Vinyl silicone oil 50.1 g, hydrogen-containing silicone oil 0.5 g, inhibitor 0.06 g, platinum catalyst 0.18 g, fumed silica 10.2 g, 400-700m 2 / g silica aerogel 1.0 g, 2-3 mm polyacrylonitrile short-cut fibers 10.1 g. Solvent: aviation 120# solvent oil 120.9 g.

[0033] Coating preparation method: (1) At room temperature, 10.1 g of polyacrylonitrile short-cut fibers were soaked in 60.1 g of aviation 120# solvent oil for about 0.5 hours and then stirred evenly.

[0034] (2) Weigh 50.1 g of vinyl silicone oil, 0.5 g of hydrogen-containing silicone oil and 0.06 g of inhibitor and add them to 60.8 g of aviation 120# solvent oil and mix them evenly. Then add 0.18 g of platinum catalyst and mix evenly.

[0035] (3) Weigh 10.2 g of fumed silica and 1.0 g of silica aerogel in sequence, and add them to the organosilicon slurry prepared in step (2), and stir evenly.

[0036] (4) Add the polyacrylonitrile short-cut fibers impregnated in step (1) and solvent to the slurry prepared in step (3), and mix them evenly by mechanical stirring to obtain the slurry for sound-absorbing and noise-reducing coating.

[0037] (5) The slurry prepared in step (4) is manually applied to polytetrafluoroethylene molds with diameters of 30 mm and 100 mm, and cured at 120°C for 5 hours to form a coating with a gradient distribution of nano- and micron-sized pores. The average density of the coating is 0.44 g / cm³. 3 The thickness is ~6.4 mm.

[0038] Example 4 In this embodiment, different primer formulations were used to prepare a double-layer sound-absorbing, noise-reducing, flame-retardant, lightweight organosilicon coating.

[0039] The raw materials and weight ratio of the surface layer of the sound-absorbing, noise-reducing, and flame-retardant lightweight organosilicon coating are as follows: Vinyl silicone oil 25.0 g, hydrogen-containing silicone oil 0.25 g, inhibitor 0.06 g, platinum catalyst 0.24 g, fumed silica 5.07 g, 500-600m 2 / g silica aerogel 0.54 g, 2-3 mm chopped polyacrylonitrile fibers 2.53 g. Solvent: aviation 120# solvent oil 53.7 g.

[0040] The raw materials and weight ratio of the sound-absorbing, noise-reducing, and flame-retardant lightweight silicone coating substrate are as follows: Vinyl silicone oil 25.0 g, hydrogen-containing silicone oil 0.25 g, inhibitor 0.06 g, platinum catalyst 0.24 g, fumed silica 5.0 g, 500-600m 2 / g silica aerogel 0.54 g, 2-3 mm polyacrylonitrile short-cut fibers 5.0 g. Solvent: aviation 120# solvent oil 66.85 g.

[0041] Coating preparation method: (1) At room temperature, 2.53 g of polyacrylonitrile short-cut fibers were soaked in 25.5 g of aviation 120# solvent oil for about 0.5 hours and then stirred evenly.

[0042] (2) Weigh 25.0 g of vinyl silicone oil, 0.25 g of hydrogen-containing silicone oil and 0.06 g of inhibitor and add them to 28.2 g of aviation 120# solvent oil and mix them evenly. Then add 0.24 g of platinum catalyst and mix evenly.

[0043] (3) Weigh 5.07 g of fumed silica and 0.54 g of silica aerogel in sequence, add them to the organosilicon slurry prepared in step (2) in sequence, and stir evenly.

[0044] (4) Add the polyacrylonitrile short-cut fibers impregnated in step (1) and solvent to the slurry prepared in step (3), and mix them evenly by mechanical stirring to obtain the slurry of the bottom layer of the sound-absorbing and noise-reducing coating.

[0045] (5) The slurry prepared in step (4) is applied by hand to polytetrafluoroethylene molds with diameters of 30 mm and 100 mm, and cured at 110°C for 4 hours to form a bottom coating with a gradient distribution of nano- and micron-sized pores. The thickness is ~2.0 mm.

[0046] (6) At room temperature, 5 g of polyacrylonitrile short-cut fibers were soaked in 33.25 g of aviation 120# solvent oil for about 0.5 hours and then stirred evenly.

[0047] (7) Weigh 25.0 g of vinyl silicone oil, 0.25 g of hydrogen-containing silicone oil and 0.06 g of inhibitor and add them to 33.25 g of aviation 120# solvent oil and mix evenly. Then add 0.24 g of platinum catalyst and mix evenly.

[0048] (8) Weigh 5.0 g of fumed silica and 0.54 g of silica aerogel in sequence, add them to the organosilicon slurry prepared in step (6) in sequence, and stir evenly.

[0049] (9) Add the short-cut polyacrylonitrile fibers impregnated in step (6) and the solvent to the slurry prepared in step (8), and mix them evenly by mechanical stirring to obtain the slurry for the sound-absorbing and noise-reducing coating surface.

[0050] (10) The slurry prepared in step (4) is manually coated onto the underlayer coating prepared in step (5), and then cured at 110°C for 4 hours to form a coating with a gradient distribution of nano- and micron-sized pores. The average density of the double-layer coating is 0.49 g / cm³. 3 The total coating thickness is ~4.6 mm.

[0051] It is worth noting that the silica content and filler formulation of the bottom coating are similar to those of Example 2, and the silica content and filler formulation of the top coating are similar to those of Example 1. However, the amounts of inhibitor and catalyst in the double-layer coating formulation differ somewhat. The inhibitor-to-catalyst ratio is 0.25, which is within the same range as the 0.18~0.27 ratios in Examples 1 and 2. Therefore, the properties of the single silica gel in this example can be referenced from Examples 1 and 2. The inhibitor delays the addition reaction, allowing time for the application process. The catalyst promotes the addition reaction. With their ratios within a certain range, the microstructures of the obtained coating samples are comparable.

[0052] Example 5 In this embodiment, a double-layer sound-absorbing, noise-reducing, flame-retardant, lightweight organosilicon coating is prepared using a primer and top coat formulation.

[0053] The raw materials and weight ratio of the sound-absorbing, noise-reducing, and flame-retardant lightweight silicone coating substrate are as follows: Vinyl silicone oil 25.361 g, hydrogen-containing silicone oil 0.253 g, inhibitor 0.01 g, platinum catalyst 0.026 g, fumed silica 5.04 g, 500-600m 2 / g silica aerogel 0.507 g, 3 mm polyacrylonitrile short-cut fibers 7.505 g. Solvent: Aviation 120 solvent oil 60.13 g.

[0054] The raw materials and weight ratio of the top layer of the sound-absorbing, noise-reducing, and flame-retardant lightweight silicone coating are as follows: Commercial LK1500-28 silica gel A component 25.108 g, commercial LK1500-28 silica gel B component 25.020 g, 2 μm barium sulfate 25.202 g.

[0055] Coating preparation method: (1) At room temperature, 7.505 g of polyacrylonitrile short-cut fibers were soaked in 30.105 g of aviation 120# solvent oil for about 0.5 hours and then stirred evenly.

[0056] (2) Weigh 25.361 g of vinyl silicone oil, 0.253 g of hydrogen-containing silicone oil and 0.01 g of inhibitor and add them to 30.025 g of aviation 120# solvent oil and mix them evenly. Then add 0.026 g of platinum catalyst and mix evenly.

[0057] (3) Weigh 5.04 g of fumed silica and 0.507 g of silica aerogel in sequence, and add them to the silicone slurry prepared in step (2). Stir evenly using a vacuum rotary mixer with a speed of 1000-1500 rpm and a vacuum degree of 0.05 Pa.

[0058] (4) Add the polyacrylonitrile short-cut fibers impregnated in step (1) and solvent to the slurry prepared in step (3), and stir evenly using a vacuum rotary mixer with a speed of 200-500 rpm and a vacuum degree of 0.05 Pa to obtain the slurry for the sound-absorbing and noise-reducing coating primer.

[0059] (5) The slurry prepared in step (4) is applied manually to polytetrafluoroethylene molds with diameters of 30 mm and 100 mm, and cured at 110°C for 4 hours to form a coating substrate with a gradient distribution of nano and micron pores.

[0060] (6) At room temperature, weigh 12.503 g of 2 μm barium sulfate and add 25.108 g of commercial LK1500-28 silica gel A component. Stir evenly with a vacuum self-rotation and revolution stirrer at 1000~1500 rpm and a vacuum degree of 0.05 Pa.

[0061] (7) Weigh 12.699 g of 2 μm barium sulfate and add 25.020 g of commercial LK1500-28 silica gel B component. Stir evenly at 1000~1500 rpm and 0.05 Pa using a vacuum self-rotation and revolution stirrer.

[0062] (8) Stir the slurry from steps (6) and (7) evenly at 1000~1500 rpm and 0.05 Pa using a vacuum self-rotation and revolution mixer to obtain the slurry for the top layer of the sound-absorbing and noise-reducing coating.

[0063] (9) The slurry from step (8) is applied manually onto the primer obtained in step (5) to prepare a primer / topcoat composite coating, which is cured at room temperature. The thickness of the composite coating is ~6.0 mm, of which the thickness of the top layer is approximately 0.5~1 mm.

[0064] Comparative Example 1 Commercially available 20 mm thick PP+PET two-component sound-absorbing cotton composite 2 mm thick EPDM sound insulation board, cut into cylinders with diameters of 30 mm and 100 mm as comparison examples. This is a commercially available product; the EPDM is from TELG, model: TEGE-35, and the PP / PET is from Wuhu Yuefei, model: HSF350.

[0065] Comparative Example 2 The silicone rubber coating without added polyacrylonitrile fibers has the following composition: 25.0 g vinyl silicone oil, 0.25 g hydrogen-containing silicone oil, 0.06 g inhibitor, 0.24 g platinum catalyst, 5.07 g fumed silica, and 500-600m 2 / g silica aerogel 0.54 g. Solvent: aviation 120# solvent oil 10 g. Coating thickness approximately 9 mm.

[0066] Coating preparation method: (1) Weigh 25.0 g of vinyl silicone oil, 0.25 g of hydrogen-containing silicone oil and 0.06 g of inhibitor in sequence and add them to 10 g of aviation 120# solvent oil and mix evenly. Then add 0.24 g of platinum catalyst and mix evenly.

[0067] (2) Weigh 5.07 g of fumed silica and 0.54 g of silica aerogel in sequence, and add them to the organosilicon slurry prepared in step (1) in three batches. Each time, use vacuum revolution and rotation to stir and mix evenly. The rotation speed is 1000-1500 rpm and the vacuum degree is 0.05 Pa.

[0068] (3) The slurry prepared in step (2) is coated onto polytetrafluoroethylene molds with diameters of 30 mm and 100 mm and cured at 110°C for 4 hours to form a silicone coating without added polyacrylonitrile fibers.

[0069] Comparative Example 3 Single top-coating silicone coating (barium sulfate-free), its composition: Commercial LK1500-28 silicone A component 25.108 g, commercial LK1500-28 silicone B component 25.020 g. The coating thickness is approximately 5 mm.

[0070] Coating preparation method: Weigh 25.108 g of commercial LK1500-28 silica gel component A and 25.020 g of component B, and mix them evenly using a vacuum rotary mixer with parameters set at 1000-1500 rpm and a vacuum degree of 0.05 Pa.

[0071] Comparative Example 4 Single top-coating silicone rubber coating (containing barium sulfate), its composition is as follows: Commercial LK1500-28 silica gel A component 25.108 g, commercial LK1500-28 silica gel B component 25.020 g, 2 μm barium sulfate 25.202 g.

[0072] Coating preparation method: (1) At room temperature, weigh 12.503 g of 2 μm barium sulfate and add 25.108 g of commercial LK1500-28 silica gel A component. Stir evenly at 1000~1500 rpm and 0.05 Pa using a vacuum self-rotation and revolution stirrer.

[0073] (2) Weigh 12.699 g of 2 μm barium sulfate and add 25.020 g of commercial LK1500-28 silica gel B component. Stir evenly in a vacuum self-rotation and revolution stirrer at 1000~1500 rpm and a vacuum degree of 0.05 Pa.

[0074] (3) Stir the slurry from steps (1) and (2) evenly at 1000~1500 rpm and 0.05 Pa using a vacuum rotary mixer to obtain a single top coating slurry.

[0075] (4) Apply the slurry from step (3) manually into a 30 mm or 100 mm polytetrafluoroethylene mold and cure at room temperature. The coating thickness is ~1.5 mm.

[0076] Samples from the above embodiments and comparative examples were taken and tested according to relevant standards: Based on GB / Z27764-2011 "Measurement of Sound Transmission Loss in Acoustic Impedance Tubes - Transfer Matrix Method" and GB / T 18696.2-2002 "Measurement of Sound Absorption Coefficient and Acoustic Impedance in Acoustic Impedance Tubes - Part 2: Transfer Function Method", the sound insulation and sound absorption coefficient of the coatings were measured at room temperature in the frequency range of 100Hz~5000Hz. The test results are as follows. Figure 1 As shown.

[0077] from Figure 1As can be seen, Example 5, with its base / top coating composite coating, exhibits significantly higher sound absorption and noise reduction performance (sound loss value 25~50 dB) over the 20mm PP / PET + 2mm EPDM wrapping scheme in Comparative Example 1 (15~35 dB) across a wide frequency range of 1000-6500 Hz. Example 1, with its sound-absorbing coating, shows similar sound loss performance to the wrapping scheme in Comparative Example 1. In the 1000-4000 Hz range, the former's sound loss value (16-30 dB) is higher than the latter's (15-28.9 dB), while in the 4000-6500 Hz range, the sound loss value (27-30.3 dB) is lower than the latter's (28.9-35.5 dB). Examples 3 and 4 have higher sound absorption coefficients than Comparative Example 1 (0.631) in the 2700-5450 Hz range, with the highest value reaching 0.863. However, the sound loss of Examples 1-4 in the low-frequency range of 250-1000 Hz is 6.7-15.6 dB, which is less than that of the wrapping scheme of Comparative Example 1 (10.1-18.7 dB), and the low-frequency sound absorption coefficient is also lower than that of the wrapping scheme of Comparative Example 1.

[0078] It is worth mentioning that the single top-coating silicone rubber coating (containing barium sulfate) in Comparative Example 4 had the best sound insulation effect, but its thickness was 1.5-3 times that of the top coating in Example 5. This is because barium sulfate has a density of ~4.5 g / cm³. 3 Therefore, silicone coatings containing barium sulfate are more prone to sagging, leading to uneven acoustic thickness and making it difficult to control thickness accuracy. Furthermore, under continuous low-frequency vibration conditions in the system, thicker coatings are more likely to peel off completely than thinner coatings. Therefore, a single top-coating solution is not recommended for sound absorption and noise reduction.

[0079] The macroscopic morphology of the coatings in Examples 1 and 5 is as follows: Figure 2 As shown in (a) and (b). Figure 3 (a, b) are PP / PET and EDPM composite materials in Comparative Example 1. Figure 3 (c, d) represent silicone rubber in Comparative Example 2. From... Figure 2 It can be seen that the coating thickness is 5-6 mm. In the single primer coating, the upper surface of Example 1 is relatively dense, while the lower surface is loose and porous. In the primer / topcoat composite coating, the topcoat of Example 5 is dense, while the primer is loose and porous, with no delamination between the two layers and good interfacial bonding. Figure 4 The image shows the microstructure of the primer coating. It reveals micron-sized layered pores within the primer coating. Micro- and nano-sized pores exist between the polyacrylonitrile fibers, and between the fibers and the fumed silica, silica aerogel, and silicone rubber matrix. The short-range ordered, long-range disordered fiber distribution constructs a complex pore structure.

[0080] Short-cut polyacrylonitrile fibers can dissipate sound energy through sound wave emission, self-vibration deformation, and interfacial friction. They can also form micron-scale lamellar channels and disordered nanoscale channels between fibers, between fibers and the matrix, fumed silica, and between fibers and silica aerogel, achieving mid-to-high frequency sound absorption. Furthermore, short-cut polyacrylonitrile fibers can improve the stiffness of silicone rubber, helping to prevent cracking due to solvent evaporation. The role of silica aerogel is twofold: firstly, to provide nanopores, absorbing high-frequency sound waves using the principle of localized resonance; and secondly, to effectively prevent silicone rubber from shrinking due to solvent evaporation. Silicone rubber provides a substrate with good viscoelasticity within a temperature range of -40℃ to 120℃.

[0081] In this double-layer composite coating, the dense top coat and the porous bottom coat exhibit a significant impedance mismatch, forming a sound-absorbing and sound-insulating composite sound absorption and noise reduction system. Short-cut polyacrylonitrile fibers not only act as excellent pore-forming agents but also serve as sound energy dissipation carriers, providing the bottom layer with superior sound absorption performance. According to the mass law, barium sulfate, with its high density, can significantly improve the sound insulation performance of the silicone rubber matrix, effectively blocking sound waves that the sound-absorbing layer cannot dissipate. Silicone rubber, acting as a viscoelastic carrier, cleverly achieves a tight bond between the electro-hydraulic substrate and the coating. Therefore, this composite coating system can achieve excellent sound absorption and noise reduction effects with its thin thickness.

[0082] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. An application of a lightweight organosilicon coating, characterized in that, The lightweight organosilicon coating is used to prepare a sound-absorbing, noise-reducing, and flame-retardant coating, which includes a base layer and a top layer. The top layer is made of silicone coating. The silicone coating includes the following components and their weight percentages: 50 parts of component A of LK1500-28 silicone, 50 parts of component B of LK1500-28 silicone, and 50 parts of barium sulfate. The barium sulfate has a particle size of 2 to 10 μm. The bottom layer is made using the aforementioned lightweight organosilicon coating; The lightweight silicone coating comprises the following components and their weight percentages: Vinyl silicone oil 50-51 parts, Hydrogen-containing silicone oil, 0.5 to 0.6 parts. Inhibitor 0.01 ~ 2 parts, Platinum catalyst 0.05 ~ 0.5 parts, 3 to 12 parts of fumed silica 1 to 1.1 parts of silica aerogel 5 to 20 parts of chopped polyacrylonitrile fibers; The vinyl silicone oil is selected from terminal vinyl silicone oil or side-chain high vinyl silicone oil, with a vinyl content of 0.32%. 0.02 wt%, viscosity 900 ~ 1100 cP; the hydrogen-containing silicone oil is selected from low-hydrogen silicone oil with a hydrogen content of 0.5 ~ 0.6 wt%; the inhibitor is selected from ethynylcycloethanol or methylbutynol; the platinum catalyst is selected from Karstedt catalyst; The fumed silica is selected from hydrophobic fumed silica with a specific surface area of ​​90-130 m². 2 / g; the specific surface area of ​​the silica aerogel is 400~700 m² / g. 2 / g; The average length of the chopped polyacrylonitrile fibers is 2 to 5 mm, and the average diameter is 10 to 30 μm.

2. The application of the lightweight organosilicon coating according to claim 1, characterized in that, The sound-absorbing, noise-reducing, and flame-retardant coating is used as a sound-absorbing and noise-reducing coating for electric drive systems of new energy vehicles, for the inner side of aircraft skin, for the inner side of rail train skin, or for the inner side of deep-sea ships.

3. The application of the lightweight organosilicon coating according to claim 1, characterized in that, The method for preparing the underlayer of the lightweight organosilicon coating includes: Vinyl silicone oil, hydrogen-containing silicone oil, inhibitor, platinum catalyst, fumed silica, and silica aerogel are mixed and prepared into a first raw material liquid; a second raw material liquid containing short-cut polyacrylonitrile fibers is mixed with the first raw material liquid, coated, and cured by heating at 100~150℃ to obtain the final product.

4. The application of the lightweight organosilicon coating according to claim 1, characterized in that, The method for preparing the top layer of the silicone coating includes: 45-55 wt% of barium sulfate is mixed with component A of LK1500-28 silicone to obtain a first mixture; the remaining barium sulfate is mixed with component B of LK1500-28 silicone to obtain a second mixture; the first mixture and the second mixture are mixed, coated onto a substrate, and cured at room temperature to obtain the final product.

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