Lightweight sound-absorbing cotton composite material and preparation method thereof

Abstract

The present application relates to sound-absorbing sound-insulating material technical field, especially light weight sound-absorbing cotton composite material and its preparation method.The composite material includes polyester fiber sound-absorbing cotton layer, adhesive layer and PET film layer which are stacked in turn;The adhesive layer is formed by curing grid-shaped adhesive strip;The adhesive includes unsaturated polyester resin, 4-hydroxybutyl vinyl ether, polyvinyl acetate, fumed silica, methyl methacryloyl silane, reactive phosphate methacrylate, cobalt naphthenate is stirred uniformly, then add peroxide methyl ethyl ketone.The present application has good dimensional stability, interface bonding stability and medium-high frequency sound transmission loss performance by the synergistic effect of PET film, adhesive layer and polyester fiber sound-absorbing cotton while ensuring lightweight, and is suitable for automotive, rail transit, ship, engineering machinery and closed cabin interior sound-insulating parts.

Description

Technical Field

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

[0002] As automobiles, rail transit, ships, construction machinery, and various enclosed cabins continue to demand lighter weight, greater passenger comfort, and improved working environments, interior and sound insulation components not only need to have sound absorption properties but also need to take into account sound wave reflection and dimensional stability.

[0003] Existing sound-absorbing materials are typically made of polyester fiber, polypropylene fiber, glass fiber, or foamed resin. Among them, polyester fiber sound-absorbing cotton is lightweight, corrosion-resistant, easy to process, and recyclable. Its interconnected fiber pores allow incident sound waves to cause air vibrations within the pores, and the sound energy is dissipated through air viscosity loss, fiber friction, and heat exchange, thus exhibiting good absorption of mid-to-high frequency noise.

[0004] However, low-area-density polyester fiber sound-absorbing cotton on its own mainly relies on its porous structure to absorb sound energy. Its area density and airflow resistance are limited, resulting in insufficient blocking ability for transmitted sound waves. While increasing the thickness or area density of the sound-absorbing cotton can improve acoustic performance to some extent, it will increase the material mass and space occupation, which is not conducive to installation and lightweight design in automobiles, rail vehicles, and confined cabins.

[0005] Therefore, how to improve the interfacial bonding stability and enhance the sound absorption effect while retaining the open pores of polyester fiber sound-absorbing cotton has excellent research prospects. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a lightweight sound-absorbing cotton composite material and its preparation method.

[0007] A lightweight sound-absorbing cotton composite material includes a polyester fiber sound-absorbing cotton layer, an adhesive layer, and a PET film layer stacked sequentially. The polyester fiber sound-absorbing cotton layer is made of polyethylene terephthalate fiber, with a thickness of 12-25 mm and a unit area mass of 90-180 g / m². 2 ; The thickness of the PET film layer is 12-35μm, and the side of the PET film facing the adhesive layer is corona treated, with a surface tension of 44-54mN / m on the corona treated side. The adhesive layer is formed by curing adhesive strips arranged in a grid pattern, with the gaps in the grid not covered by adhesive, and the amount of adhesive applied is 28-36 g / m². 2 .

[0008] Preferably, the workable time of the adhesive is 15-25 minutes.

[0009] Preferably, the mesh coverage of the adhesive layer is 40-65%.

[0010] Preferably, the adhesive comprises, by weight, 100 parts of unsaturated polyester resin, 15-22 parts of 4-hydroxybutyl vinyl ether, 3-6 parts of polyvinyl acetate, 0.8-1.5 parts of fumed silica, 0.5-1.2 parts of methacryloxysilane, 0.3-1.0 parts of reactive phosphate ester methacrylate, 0.2-0.5 parts of cobalt naphthenate, and 0.8-1.5 parts of methyl ethyl ketone peroxide.

[0011] Preferably, the method for preparing the adhesive includes the following steps: (1) Mix unsaturated polyester resin, 4-hydroxybutyl vinyl ether and polyvinyl acetate, and stir at 300-500 r / min for 15-25 min at 25-30℃ to obtain preform a; (2) Add fumed silica to preform a while stirring and stir for 10-20 min; then add methacryloxysilane and reactive phosphate methacrylate and continue stirring for 5-10 min to obtain preform b. (3) Vacuum degassing of preform b for 8-12 min, vacuum gauge pressure of -0.075 to -0.090 MPa, degassing temperature of 15-25℃; before coating, add cobalt naphthenate and stir evenly, then add methyl ethyl ketone peroxide and stir at 40-60 r / min for 3-5 min to obtain adhesive.

[0012] The preparation method of the above-mentioned lightweight sound-absorbing cotton composite material includes the following steps: S1. PET film is continuously unwound and passed through a crease roller to form longitudinal creases with ridges parallel to the material's running direction without puncturing the film. S2. With the corona-treated surface of the PET film facing the coating roller, the adhesive is applied to the corona-treated surface using the coating roller to form intersecting grid strips. S3. The coated PET film and the continuously unwound polyester fiber sound-absorbing cotton are introduced into the composite roller together, so that the adhesive comes into contact with the surface of the polyester fiber sound-absorbing cotton and is composited. S4. The composite material is sent into a three-stage hot air drying tunnel for curing, and then cooled to obtain a lightweight sound-absorbing cotton composite material.

[0013] Preferably, in S1, the fold height is 0.4-0.8 mm and the fold spacing is 8-15 mm.

[0014] Preferably, in S3, the surface temperature of the composite roller is 35-45℃.

[0015] Preferably, in S4, the three-section hot air drying duct includes: The first stage involves a temperature of 55-65℃ and a dwell time of 2-4 minutes. The second stage involves a temperature of 75-85℃ and a dwell time of 3-5 minutes. The third stage involves a temperature of 95-105℃ and a dwell time of 3-5 minutes.

[0016] Preferably, the three-section hot air drying duct uses circulating hot air with a hot air flow rate of 2-4 m / s. Beneficial effects

[0017] This invention combines a polyester fiber sound-absorbing cotton layer, a mesh-like adhesive layer, and a PET film layer, achieving sound absorption, sound wave reflection, and interface damping with a relatively low unit area mass. The interconnected pores within the polyester fiber sound-absorbing cotton allow for air viscosity loss, while the PET film creates a change in acoustic impedance on the surface of the composite material, reflecting some incident sound waves and improving the insufficient sound wave reflection and blocking capabilities of low surface density sound-absorbing cotton.

[0018] The adhesive of this invention employs a grid-like discontinuous coating method, which effectively preserves the open pores on the surface of the sound-absorbing cotton while ensuring effective bonding between the PET film and the sound-absorbing cotton, thereby reducing the amount of adhesive used and the unit area mass of the composite material. The wrinkles on the PET film provide deformation space for the film, and the dispersed grid adhesive strips form multiple constraint areas on the wrinkles. When the film is subjected to sound pressure or structural vibration, the adhesive layer undergoes shear deformation, and some of the vibrational energy is dissipated through internal friction and molecular chain segment movement within the adhesive layer.

[0019] This invention retains the open pores of polyester fiber sound-absorbing cotton while using adhesives to effectively improve interfacial bonding stability while maintaining low curing shrinkage and moderate flexibility. It has the advantages of high production efficiency, easy control of process parameters and suitability for large-scale manufacturing. Moreover, the preparation method is simple and suitable for large-scale promotion and application. Attached Figure Description

[0020] Figure 1 The image shows a comparison of the 180° interface peel strength test results for Example 5, Comparative Example 1, and Comparative Example 2. Detailed Implementation

[0021] The present invention will be further explained below with reference to specific embodiments.

[0022] The unsaturated polyester resin used below is from Mitsui, Japan, brand name FTR8100. Polyvinyl acetate was purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd., with a molecular weight of 50,000. Fumed silica is from Evonik, Germany, brand name AEROSILR972. The adhesive layer described below adopts a grid-like discontinuous coating structure. Specifically, an orthogonal grid-like discontinuous adhesive layer is formed on the corona-treated surface of the PET film using a coating roller. The grid consists of mutually perpendicular longitudinal and transverse adhesive strips, where the grid pitch is the distance between the center lines of adjacent adhesive strips, the grid gap is the distance between the edges of adjacent adhesive strips, and the strip width is the width of the longitudinal or transverse adhesive strip.

[0023] Example 1 A lightweight sound-absorbing cotton composite material, the structure of which includes a polyester fiber sound-absorbing cotton layer, an adhesive layer and a PET film layer stacked in sequence.

[0024] The polyester fiber sound-absorbing cotton layer is 12mm thick and has a unit area mass of 90g / m². 2 The PET film layer is 12μm thick, and the side facing the adhesive layer is corona treated with a surface tension of 44mN / m.

[0025] The adhesive layer adopts a grid-like discontinuous coating structure, and the adhesive coating amount is 28g / m². 2 .

[0026] The specific steps for preparing the adhesive are as follows: (1) Add 100g of unsaturated polyester resin, 15g of 4-hydroxybutyl vinyl ether and 3g of polyvinyl acetate to a stirring container, and stir at 300r / min for 15min at 25℃ to obtain preform a; (2) Under continuous stirring, 0.8g of fumed silica was added to preform a and stirred for 10min; then 0.5g of γ-methacryloxypropyltrimethoxysilane and 0.3g of 2-hydroxyethyl methacrylate phosphate were added and stirred for 5min to obtain preform b. (3) Place the preform b under vacuum for 8 minutes to degas. The degassing temperature is 15℃ and the vacuum gauge pressure is -0.075MPa. Before coating, add 0.2g of cobalt naphthenate and stir evenly. Then add 0.8g of methyl ethyl ketone peroxide and stir at 40r / min for 3 minutes to obtain the adhesive.

[0027] The workable time of the resulting adhesive is 15 minutes.

[0028] The preparation method of the above-mentioned lightweight sound-absorbing cotton composite material includes the following steps: After the PET film is continuously unwound, it first passes through a crease roller to form longitudinal creases with ridges parallel to the material's running direction without puncturing the PET film. The crease height is 0.4 mm and the crease spacing is 8 mm.

[0029] With the corona-treated surface of the PET film facing the coating roller, the adhesive is applied to the corona-treated surface of the PET film using the coating roller to form a discontinuous adhesive layer in the form of an orthogonal grid. The longitudinal and transverse adhesive strips of the grid are perpendicular to each other, the grid pitch is 8 mm, the strip width is 2.07 mm, and the grid gap is 5.93 mm.

[0030] The coated PET film and polyester fiber sound-absorbing cotton are fed into the composite roller together, and the roller surface temperature is 35℃.

[0031] The composite material enters a three-stage hot air drying tunnel for curing: The first stage temperature is 55℃, and the dwell time is 2 minutes; The second temperature is 75℃, and the dwell time is 3 minutes; The third temperature is 95℃, and the dwell time is 3 minutes; The circulating hot air velocity is 2 m / s.

[0032] The material is cooled to room temperature after being output from the drying tunnel.

[0033] Example 2: A lightweight sound-absorbing cotton composite material, the raw materials and structural parameters of which are as follows: The polyester fiber sound-absorbing cotton layer is 25mm thick and has a unit area mass of 180g / m². 2 The PET film layer thickness is 35μm, and the surface tension of the corona-treated surface is 54mN / m; the adhesive coating amount is 36g / m. 2 .

[0034] The specific steps for preparing the adhesive are as follows: (1) Add 100g of unsaturated polyester resin, 22g of 4-hydroxybutyl vinyl ether and 6g of polyvinyl acetate to a stirring container, and stir at 300r / min for 25min at 30℃ to obtain preform a; (2) Under continuous stirring, 1.5g of fumed silica was added to preform a and stirred for 20min; then 1.2g of γ-methacryloxypropyltrimethoxysilane and 1g of 2-hydroxyethyl methacrylate phosphate were added and stirred for another 10min to obtain preform b. (3) Place the preform b under vacuum for 12 min to degas. The degassing temperature is 25℃ and the vacuum gauge pressure is -0.09MPa. Before coating, add 0.5g of cobalt naphthenate and stir evenly. Then add 1.5g of methyl ethyl ketone peroxide and stir at 60r / min for 5 min to obtain the adhesive.

[0035] The workable time of the resulting adhesive is 25 minutes.

[0036] The preparation method of the above-mentioned lightweight sound-absorbing cotton composite material includes the following steps: After the PET film is continuously unwound, it first passes through a crease roller to form longitudinal creases with ridges parallel to the material's running direction without puncturing the PET film. The crease height is 0.8 mm and the crease spacing is 15 mm.

[0037] With the corona-treated surface of the PET film facing the coating roller, the adhesive is applied to the corona-treated surface of the PET film using the coating roller to form an orthogonal grid-like discontinuous adhesive layer. The longitudinal and transverse adhesive strips of the grid are perpendicular to each other, the grid pitch is 10 mm, the strip width is 3.68 mm, and the grid gap is 6.32 mm.

[0038] The coated PET film and polyester fiber sound-absorbing cotton are fed into the composite roller together, and the roller surface temperature is 45℃.

[0039] The composite material enters a three-stage hot air drying tunnel for curing: The first stage temperature is 65℃, and the dwell time is 4 minutes; The second temperature is 85℃, and the dwell time is 5 minutes; The temperature of the third section is 105℃, and the dwell time is 5 minutes; The circulating hot air velocity is 4 m / s.

[0040] The material is cooled to room temperature after being output from the drying tunnel.

[0041] Example 3: A lightweight sound-absorbing cotton composite material, the structural parameters of which are as follows: The polyester fiber sound-absorbing cotton layer is 18mm thick and has a unit area mass of 120g / m². 2 The PET film layer thickness is 20μm, and the surface tension of the corona-treated surface is 47mN / m; the adhesive coating amount is 30g / m. 2 .

[0042] The specific steps for preparing the adhesive are as follows: (1) Add 100g of unsaturated polyester resin, 17g of 4-hydroxybutyl vinyl ether and 4g of polyvinyl acetate to a stirring container and stir at 300r / min for 15min at 27℃ to obtain preform a; (2) Under continuous stirring, 0.9g of fumed silica was added to preform a and stirred for 10min; then 0.7g of γ-methacryloxypropyltrimethoxysilane and 0.4g of 2-hydroxyethyl methacrylate phosphate were added and stirred for 7min to obtain preform b. (3) Place the preform b under vacuum for 10 min to degas. The degassing temperature is 20℃ and the vacuum gauge pressure is -0.08MPa. Before coating, add 0.25g of cobalt naphthenate and stir evenly. Then add 0.9g of methyl ethyl ketone peroxide and stir at 45r / min for 4 min to obtain the adhesive.

[0043] The workable time of the resulting adhesive is 15 minutes.

[0044] The preparation method of the above-mentioned lightweight sound-absorbing cotton composite material includes the following steps: After the PET film is continuously unwound, it first passes through a crease roller to form longitudinal creases with ridges parallel to the material's running direction without puncturing the PET film. The crease height is 0.5 mm and the crease spacing is 9 mm.

[0045] With the corona-treated surface of the PET film facing the coating roller, the adhesive is applied to the corona-treated surface of the PET film using the coating roller to form a discontinuous adhesive layer in the form of an orthogonal grid. The longitudinal and transverse adhesive strips of the grid are perpendicular to each other, the grid pitch is 9 mm, the strip width is 2.64 mm, and the grid gap is 6.36 mm.

[0046] The coated PET film and polyester fiber sound-absorbing cotton are fed into the composite roller together, and the roller surface temperature is 38℃.

[0047] The composite material enters a three-stage hot air drying tunnel for curing: The first stage temperature is 60℃, and the dwell time is 3 minutes; The second temperature is 80℃, and the dwell time is 4 minutes; The third section has a temperature of 100℃ and a dwell time of 4 minutes; The circulating hot air velocity is 3 m / s.

[0048] The material is cooled to room temperature after being output from the drying tunnel.

[0049] Example 4: A lightweight sound-absorbing cotton composite material, the structural parameters of which are as follows: The polyester fiber sound-absorbing cotton layer is 20mm thick and has a unit area mass of 150g / m². 2 The PET film layer thickness is 30μm, and the surface tension of the corona-treated surface is 51mN / m; the adhesive coating amount is 34g / m. 2 .

[0050] The specific steps for preparing the adhesive are as follows: (1) Add 100g of unsaturated polyester resin, 20g of 4-hydroxybutyl vinyl ether and 5g of polyvinyl acetate to a stirring container, and stir at 300r / min for 22min at 28℃ to obtain preform a; (2) Under continuous stirring, 1.3g of fumed silica was added to preform a and stirred for 12min; then 1g of γ-methacryloxypropyltrimethoxysilane and 0.8g of 2-hydroxyethyl methacrylate phosphate were added and stirred for 5min to obtain preform b. (3) Place the preform b under vacuum for 11 min to degas. The degassing temperature is 22℃ and the vacuum gauge pressure is -0.085MPa. Before coating, add 0.4g of cobalt naphthenate and stir evenly. Then add 1.3g of methyl ethyl ketone peroxide and stir at 50r / min for 4 min to obtain the adhesive.

[0051] The workable time of the resulting adhesive is 15 minutes.

[0052] The preparation method of the above-mentioned lightweight sound-absorbing cotton composite material includes the following steps: After the PET film is continuously unwound, it first passes through a crease roller to form longitudinal creases with ridges parallel to the material's running direction without puncturing the PET film. The crease height is 0.7 mm and the crease spacing is 13 mm.

[0053] With the corona-treated surface of the PET film facing the coating roller, the adhesive is applied to the corona-treated surface of the PET film using the coating roller to form a discontinuous adhesive layer in the form of an orthogonal grid. The longitudinal and transverse adhesive strips of the grid are perpendicular to each other, the grid pitch is 13mm, the strip width is 4.28mm, and the grid gap is 8.72mm.

[0054] The coated PET film and polyester fiber sound-absorbing cotton are fed into the composite roller together, and the roller surface temperature is 45℃.

[0055] The composite material enters a three-stage hot air drying tunnel for curing: The temperature of the first section is 63℃, and the dwell time is 4 minutes; The second temperature was 83℃, and the dwell time was 4 minutes. The temperature of the third section is 103℃, and the dwell time is 5 minutes; The circulating hot air velocity is 3.5 m / s.

[0056] The material is cooled to room temperature after being output from the drying tunnel.

[0057] Example 5 A lightweight sound-absorbing cotton composite material, the structure of which includes a polyester fiber sound-absorbing cotton layer, an adhesive layer and a PET film layer stacked in sequence.

[0058] The polyester fiber sound-absorbing cotton layer is made of polyethylene terephthalate fiber, with a thickness of 18mm and a unit area weight of 135g / m². 2 .

[0059] The PET film layer is 25μm thick, and the side facing the adhesive layer is corona treated. The surface tension of the corona-treated surface is 49mN / m.

[0060] The preparation process of the adhesive is as follows: (1) Add 100g of unsaturated polyester resin, 18g of 4-hydroxybutyl vinyl ether and 4.5g of polyvinyl acetate to a stirring container and stir at 400r / min for 20min at 26℃ to obtain preform a; (2) Under continuous stirring, 1.1g of fumed silica was added to preform a in batches and stirred for 15min; then 0.8g of γ-methacryloxypropyltrimethoxysilane and 0.6g of 2-hydroxyethyl methacrylate phosphate were added and stirred for 8min to obtain preform b. (3) Place the preform b under vacuum for 10 min to degas, control the degassing temperature at 20℃ and the vacuum gauge pressure at -0.080MPa; before coating, add 0.35g cobalt naphthenate and 1.1g methyl ethyl ketone peroxide, stir at 45r / min for 4 min to obtain the adhesive.

[0061] The workable time of the resulting adhesive is 20 minutes. The adhesive is applied and laminated within this workable time to avoid uneven coating or decreased interfacial adhesion due to pre-curing.

[0062] The preparation method of the above-mentioned lightweight sound-absorbing cotton composite material includes the following steps: After the PET film is continuously unwound, it first passes through a crease roller to form longitudinal creases with ridges parallel to the material's running direction without puncturing the PET film. The crease height is 0.6 mm and the crease spacing is 10 mm.

[0063] With the corona-treated surface of the PET film facing the coating roller, the adhesive is applied to the corona-treated surface of the PET film using the coating roller to form a discontinuous adhesive layer in the form of an orthogonal grid. The longitudinal and transverse adhesive strips of the grid are perpendicular to each other, the grid pitch is 10 mm, the strip width is 2.79 mm, and the grid gap is 7.21 mm.

[0064] The adhesive coating amount is controlled at 32g / m². 2 .

[0065] The coated PET film and continuously unwound polyester fiber sound-absorbing cotton are fed together into the composite roller, allowing the adhesive to come into contact with the surface of the sound-absorbing cotton. The roller surface temperature is controlled at 40℃.

[0066] The composite material enters a three-stage hot air drying tunnel for curing: The first stage temperature is 60℃, and the dwell time is 3 minutes; The second temperature is 80℃, and the dwell time is 4 minutes; The third section has a temperature of 100℃ and a dwell time of 4 minutes; The circulating hot air velocity is 3 m / s.

[0067] After the material is output from the drying tunnel, it is naturally cooled to room temperature, cut and placed in an environment of 23±2℃ and 50±10% relative humidity for 24 hours.

[0068] Comparative Example 1 The difference between Comparative Example 1 and Example 5 is that the adhesive layer adopts a continuous and uniform coating structure, instead of a grid-like discontinuous coating structure.

[0069] To ensure the validity of the comparison results, Comparative Example 1 used the same raw materials and process conditions as Example 5, with the only difference being that the adhesive was continuously and uniformly distributed on the corona-treated surface of the PET film.

[0070] Comparative Example 2 The difference between Comparative Example 2 and Example 5 is that no fumed silica is added to the adhesive, while other components and process conditions remain unchanged.

[0071] 1. Sample preparation Circular samples were cut from the composite materials prepared in Example 5, Comparative Example 1, and Comparative Example 2, respectively.

[0072] The diameter of the specimen should match the inner diameter of the impedance tube specimen clamp used. If an impedance tube with an inner diameter of 29 mm is used, the specimen diameter can be controlled at 29 mm, with the actual size based on the effective inner diameter of the specimen clamp. The specimen thickness should remain the actual thickness after material composite, without compression or pre-compression treatment.

[0073] At least three parallel samples should be prepared for each group. The edges of the samples should be flat and there should be no obvious gaps, delamination, wrinkles, damage or local delamination. When installing the samples, the PET film layer should face the sound source side and the polyester fiber sound-absorbing cotton layer should face the receiving side.

[0074] After the sample is installed, use a low-reflectivity sealing material to seal the gap between the sample periphery and the inner wall of the impedance tube to ensure that acoustic energy cannot leak from the sample edge. The sealing material must not cover the effective test area of ​​the sample, nor should it significantly compress the sample.

[0075] 2. Sound transmission loss test The sound transmission loss of composite materials was determined using a four-microphone impedance tube system, following the test method described in ASTM E2611. The test frequency range was set to 500-6000 Hz.

[0076] The test conditions are as follows: ambient temperature 23±2℃; relative humidity 50±10%; background noise lower than the test signal, signal-to-noise ratio not less than 10dB; sample conditioning time: not less than 24h; each sample is tested at least 3 times at each frequency point. Calculate the arithmetic mean of the repeated test results for the same sample, and then calculate the arithmetic mean of the parallel samples in the same group.

[0077] The sound transmission loss TL is recorded according to the output of the test system, in dB. During the test, the installation orientation, sealing method, excitation signal, analysis bandwidth, and data processing method of each group of samples are kept consistent.

[0078] 3. Test Results 3.1 Sound Insulation Test Under the same test conditions, sample size, installation orientation, and data processing method, the test results are shown in the table below:

[0079] As shown in the table above, in the 500-2000Hz range, the sound transmission loss of Comparative Example 1 is slightly higher than that of Example 5, while in the 2500-6000Hz range, the sound transmission loss of Example 5 is higher than that of Comparative Example 1. This indicates that the structure of the present invention can generate effective interface damping in the high-frequency band and improve the sound transmission loss in the mid-to-high frequency band.

[0080] 3.2 Interface peel strength test Long strips of a specified width were cut from the composite materials obtained in Example 5, Comparative Example 1, and Comparative Example 2, so that the PET film layer and the polyester fiber sound-absorbing cotton layer formed a peelable end.

[0081] A 180° peel test was conducted using an electronic universal testing machine. The peeling speed was kept constant. The average peeling force during the peeling process was recorded and converted into peel strength per unit width, with the unit being N / 25mm.

[0082] Depend on Figure 1 It can be seen that although the interfacial peel strength of Example 5 is slightly lower than that of Comparative Example 1 which uses a continuous uniform coating structure, it still maintains a high interfacial bonding strength. At the same time, Example 5 reduces the coverage of the adhesive on the open pores of the sound-absorbing cotton by using a grid-like discontinuous adhesive structure, which is beneficial to balance interfacial bonding performance and acoustic performance.

[0083] In Comparative Example 2, due to the absence of fumed silica, the thixotropic stability, coating retention ability, and interfacial bonding stability of the adhesive decreased, and the interfacial peel strength was significantly reduced.

[0084] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A lightweight sound-absorbing cotton composite material, characterized in that, It includes a polyester fiber sound-absorbing cotton layer, an adhesive layer, and a PET film layer stacked in sequence; The polyester fiber sound-absorbing cotton layer is made of polyethylene terephthalate fiber, with a thickness of 12-25 mm and a unit area mass of 90-180 g / m². 2 ; The thickness of the PET film layer is 12-35μm, and the side of the PET film facing the adhesive layer is corona treated, with a surface tension of 44-54mN / m on the corona treated side. The adhesive layer is formed by curing adhesive strips arranged in a grid pattern, with the gaps in the grid not covered by adhesive, and the amount of adhesive applied is 28-36 g / m². 2 .

2. The lightweight sound-absorbing cotton composite material according to claim 1, characterized in that, The adhesive layer has a grid coverage of 40-65%.

3. The lightweight sound-absorbing cotton composite material according to claim 1, characterized in that, The adhesive comprises, by weight, 100 parts of unsaturated polyester resin, 15-22 parts of 4-hydroxybutyl vinyl ether, 3-6 parts of polyvinyl acetate, 0.8-1.5 parts of fumed silica, 0.5-1.2 parts of methacryloxysilane, 0.3-1.0 parts of reactive phosphate ester methacrylate, 0.2-0.5 parts of cobalt naphthenate, and 0.8-1.5 parts of methyl ethyl ketone peroxide.

4. A method for preparing a lightweight sound-absorbing cotton composite material as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Continuously unwind the PET film to form longitudinal folds with ridges parallel to the material's running direction without puncturing the film. S2. With the corona-treated surface of the PET film facing the coating roller, the adhesive is applied to the corona-treated surface using the coating roller to form intersecting grid strips. S3. The coated PET film and the continuously unwound polyester fiber sound-absorbing cotton are introduced into the composite roller together, so that the adhesive comes into contact with the surface of the polyester fiber sound-absorbing cotton and is composited. S4. The composite material is sent into a three-stage hot air drying tunnel for curing, and then cooled to obtain a lightweight sound-absorbing cotton composite material.

5. The method for preparing the lightweight sound-absorbing cotton composite material according to claim 4, characterized in that, In S1, the fold height is 0.4-0.8mm and the fold spacing is 8-15mm.

6. The method for preparing the lightweight sound-absorbing cotton composite material according to claim 4, characterized in that, In S3, the surface temperature of the composite roller is 35-45℃.

7. The method for preparing the lightweight sound-absorbing cotton composite material according to claim 4, characterized in that, In S4, the three-section hot air drying duct includes: The first stage involves a temperature of 55-65℃ and a dwell time of 2-4 minutes. The second stage involves a temperature of 75-85℃ and a dwell time of 3-5 minutes. The third stage involves a temperature of 95-105℃ and a dwell time of 3-5 minutes.

8. The method for preparing the lightweight sound-absorbing cotton composite material according to claim 4, characterized in that, The three-section hot air drying duct uses circulating hot air with a flow rate of 2-4 m / s.

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