Laser processing micro-texture film for sound absorption structure and preparation method of laser processing micro-texture film

Abstract

The invention discloses a laser processing micro-texture film for a sound absorption structure and a preparation method thereof, and relates to the field of sound absorption films, the laser processing micro-texture film comprises a film layer, and the thickness of the film layer is not greater than 0.2 mm; the film is provided with a plurality of microtextures used for sound energy dissipation, and the microtextures are slits, micropores or aperture-seam combined structures. According to the laser processing micro-texture film for the sound absorption structure and the preparation method of the laser processing micro-texture film, a polymer material with sound absorption performance is selected as a film base material, and sound absorption reinforcing particles are uniformly dispersed in the polymer material, so that the sound absorption performance of the film is improved from the material; meanwhile, a micro-texture with a specific shape, size and distribution is prepared on the surface of the thin film by utilizing a laser processing technology, so that the sound wave absorption and scattering characteristics of the thin film are further optimized; in addition, the invention further provides a simple and efficient preparation method, the preparation process of the thin film can be accurately controlled, and large-scale industrial production is achieved.

Description

Technical Field

[0001] This invention relates to sound-absorbing film technology, specifically to a laser-processed microtextured film for sound-absorbing structures and its preparation method. Background Technology

[0002] In today's society, with the increasing frequency of industrial production, transportation and various construction activities, noise pollution has become more and more serious, which has had many adverse effects on people's quality of life, physical and mental health and working environment. Therefore, developing efficient and practical sound-absorbing materials and structures to effectively reduce noise levels has become an important research topic in the field of environmental noise control.

[0003] Traditional sound-absorbing materials are mainly divided into two categories: porous sound-absorbing materials and resonant sound-absorbing materials. Porous sound-absorbing materials, such as glass wool, mineral wool, and foam plastics, rely on a large number of interconnected tiny pores inside to allow sound waves to enter the material and interact with the air in the pores through friction and adhesion, thereby converting sound energy into heat energy and dissipating it. These materials have good sound absorption performance in the mid-to-high frequency range, but their sound absorption effect in the low frequency range is often unsatisfactory. Resonant sound-absorbing materials utilize the resonance principle of the material. When the frequency of the incident sound wave matches the natural frequency of the material, the material will resonate, thereby absorbing a large amount of sound energy. Common resonant sound-absorbing structures include Helmholtz resonators, etc. However, their sound absorption frequency band is relatively narrow, and they usually only have a significant sound absorption effect near specific frequencies.

[0004] To overcome the limitations of single sound-absorbing materials, people have begun to explore the design and application of composite sound-absorbing structures. Composite sound-absorbing structures cleverly combine different types of sound-absorbing materials or structures to give full play to their respective advantages and achieve the goal of wide bandwidth and high sound absorption coefficient. For example, combining porous sound-absorbing materials with resonant sound-absorbing structures can achieve good sound absorption performance over a wide frequency range. However, there are still many challenges in the design and preparation of current composite sound-absorbing structures, such as complex structures, complicated preparation processes, and high costs, which limit their large-scale promotion and application.

[0005] Due to their unique physical and chemical properties, thin film materials have shown great application potential in the field of sound absorption. Thin films have advantages such as light weight, thin thickness, and good flexibility, and can be easily applied to various complex geometries and spatial environments. When sound waves act on the surface of the thin film, they will cause the film to vibrate. By converting sound energy into the mechanical energy of the thin film, the purpose of sound absorption is achieved.

[0006] However, the sound absorption performance of thin film materials is often limited, especially in the frequency range outside the mid-to-high frequency range, where the sound absorption effect is difficult to meet practical needs. In order to improve the sound absorption performance of thin films, researchers have tried to modify the films in various ways. For example, microporous structures are prepared on the surface of the thin film. The acoustic impedance matching and sound energy dissipation of the micropores are used to enhance the absorption capacity of the film for sound waves. However, traditional micropore preparation methods, such as mechanical drilling and chemical etching, have problems such as low processing accuracy, uneven pore size distribution, and difficulty in preparing complex-shaped micropores, which limit the further improvement of the sound absorption performance of the thin film.

[0007] Although there has been some research on sound-absorbing films and laser-processed microtextures, there are still some shortcomings. For example, some studies only focus on the simple preparation of microtextures on the film surface, while neglecting the optimization of the sound absorption performance of the film material itself; some composite sound-absorbing structures are too complex in design, with cumbersome preparation processes and high costs, making it difficult to achieve large-scale industrial production; in addition, there is a lack of in-depth and systematic research on the intrinsic relationship between the morphology, size and other parameters of laser-processed microtextures and the sound absorption performance of the film, which makes it impossible to accurately design and prepare films with specific sound absorption properties according to actual needs. Therefore, this paper proposes a laser-processed microtextured film for sound-absorbing structures and its preparation method.

[0008] This invention proposes a laser-processed microtextured thin film for sound-absorbing structures and its preparation method, aiming to solve the aforementioned problems in the prior art. This invention improves the sound absorption performance of the film by selecting a polymer material with sound-absorbing properties as the film substrate and uniformly dispersing sound-absorbing reinforcing particles within it. Simultaneously, laser processing technology is used to prepare microtextures with specific shapes, sizes, and distributions on the film surface, further optimizing the film's sound wave absorption and scattering characteristics. Furthermore, this invention provides a simple and efficient preparation method that can precisely control the film preparation process, enabling large-scale industrial production. This invention offers a new approach and method for developing high-performance, broadband sound-absorbing materials and structures, possessing significant theoretical and practical application value. Summary of the Invention

[0009] The purpose of this invention is to provide a laser-processed microtextured thin film for sound-absorbing structures and its preparation method, so as to solve the problems in the prior art.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a laser-processed microtextured thin film for sound-absorbing structures, comprising a thin film layer, wherein the thickness of the thin film layer is not greater than 0.2 mm;

[0011] The film has multiple microtextures for sound energy dissipation, the microtextures being slits, micropores, or a combination of slits and pores, and the maximum width / diameter of the microtextures is no greater than 0.3 mm;

[0012] The microtexture is formed by laser processing methods such as laser cutting, ablation, or engraving.

[0013] The microtexture is distinct from the tear seams formed by film tension contraction, depression or twisting caused by cutting with a tool in terms of cross-section, micromorphology or formation mechanism.

[0014] The thin film layer material is a polymer material with sound absorption properties, as well as aluminum film, PVC film and PET film, and sound-absorbing reinforcing particles are uniformly dispersed in the polymer material. The sound-absorbing reinforcing particles are at least one of nanoscale metal particles, ceramic particles or carbon nanotubes, and their mass accounts for 5% to 20% of the total mass of the thin film layer.

[0015] Furthermore, the microtexture has a specific cross-sectional shape, which is a conical or inverted trapezoidal structure. The conical or V-shaped cross-section is formed in the thickness direction by laser ablation or cutting, and the sidewalls of the conical or inverted trapezoidal structure have tiny uneven textures. The depth of the uneven textures is 0.01 mm to 0.05 mm, and the equivalent width of the microtexture is 0.02 mm to 0.1 mm.

[0016] Furthermore, the edge of the microtexture has a molten recasting zone or heat-affected zone formed by laser processing, and the surface of the molten recasting zone or heat-affected zone has a nanoscale rough structure with a surface roughness Ra value of 0.05μm-0.5μm.

[0017] Furthermore, the microtexture has a nonlinear geometric shape, which is a sawtooth shape, a wave shape, or a star shape.

[0018] Furthermore, the nonlinear geometric microtextures are regularly distributed on the film surface, and the equivalent width of the microtextures is 0.1 mm to 1 mm.

[0019] Furthermore, the thin film layer is provided with at least one functional coating, which is at least one of a sound-absorbing coating, a waterproof coating, or an oil-resistant coating.

[0020] Furthermore, when the functional coating is a sound-absorbing coating, the sound-absorbing coating material is a porous ceramic material or a porous metal material with a porosity of 30% to 70%.

[0021] A method for preparing laser-processed microtextured thin films for sound-absorbing structures includes the following steps:

[0022] Step 1: Prepare a membrane layer with a thickness of no more than 0.2 mm. The membrane layer material is a polymer material with sound absorption properties, as well as aluminum film, PVC film, and PET film. The film can be designed to absorb sound. After the film is processed, adding cavities to the film will give it sound absorption properties. Sound-absorbing reinforcing particles are uniformly dispersed in the polymer material. The sound-absorbing reinforcing particles are at least one of nanoscale metal particles, ceramic particles, or carbon nanotubes, and their mass accounts for 5% to 20% of the total mass of the film layer.

[0023] Step 2: Set the parameters of the laser equipment, such as power, speed, and focal position, and at the same time, establish the corresponding processing model in the computer according to the preset microtexture shape and distribution;

[0024] Step 3: The film layer is processed by laser along a preset direction to form a microtexture with specific geometric parameters. The microtexture is a slit, micropore, or pore-slit combination structure, and the maximum width / diameter of the microstructure is no greater than 0.3 mm. The microtexture is different from the tear seam formed by film layer tension contraction, depression, or twisting caused by tool engraving in terms of cross-section, micromorphology, or formation mechanism. During the laser processing, a pulsed laser is used, and the pulse frequency is 1kHz-100kHz, and the pulse width is 1ns-100ns.

[0025] Step 4: Perform surface treatment on the laser-processed film to form at least one functional coating on the film surface. The functional coating is at least one of a sound-absorbing coating, a waterproof coating, or an oil-proof coating. When forming a sound-absorbing coating, a porous ceramic material or a porous metal material is sprayed onto the film surface using plasma spraying technology to form a sound-absorbing coating with a porosity of 30% to 70%.

[0026] Step 5: The laser-processed film is bonded to the substrate with through holes by means of an adhesive layer or mechanical means. The adhesive layer is an adhesive with sound absorption properties and has a thickness of 0.01mm to 0.1mm.

[0027] Compared with existing technologies, this invention provides a laser-processed microtextured thin film for sound-absorbing structures and its preparation method. This invention improves the sound absorption performance of the film by selecting a polymer material with sound-absorbing properties as the film substrate and uniformly dispersing sound-absorbing reinforcing particles within it. Simultaneously, laser processing technology is used to prepare microtextures with specific shapes, sizes, and distributions on the film surface, further optimizing the film's sound wave absorption and scattering characteristics. Furthermore, this invention provides a simple and efficient preparation method that can precisely control the film preparation process, enabling large-scale industrial production. This invention offers a new approach and method for developing high-performance, broadband sound-absorbing materials and structures, possessing significant theoretical and practical application value. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0029] Figure 1 A flowchart illustrating the steps of a method for preparing microtextured thin films according to an embodiment of the present invention. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] As attached Figure 1 As shown:

[0032] Example 1:

[0033] This invention provides a laser-processed microtextured thin film for sound-absorbing structures and a method for preparing the same, comprising a thin film layer with a thickness not exceeding 0.2 mm;

[0034] The film has multiple microtextures for sound energy dissipation, the microtextures being slits, micropores, or a combination of slits and pores, and the maximum width / diameter of the microtextures is no greater than 0.3 mm;

[0035] The microtexture is formed by laser processing methods such as laser cutting, ablation, or engraving.

[0036] The microtexture is distinct from the tear seams formed by film tension contraction, depression or twisting caused by cutting with a tool in terms of cross-section, micromorphology or formation mechanism.

[0037] The thin film layer material is a polymer material with sound absorption properties, as well as aluminum film, PVC film and PET film, and sound-absorbing reinforcing particles are uniformly dispersed in the polymer material. The sound-absorbing reinforcing particles are at least one of nanoscale metal particles, ceramic particles or carbon nanotubes, and their mass accounts for 5%-20% of the total mass of the thin film layer.

[0038] The invention is further described in detail below. The microtexture has a specific cross-sectional shape, which is a conical or inverted trapezoidal structure. Laser ablation or cutting forms a conical or V-shaped cross-section in the thickness direction. The sidewalls of the conical or inverted trapezoidal structure have minute uneven textures with a depth of 0.01 mm to 0.05 mm. The equivalent width of the microtexture is 0.02 mm to 0.1 mm. The edges of the microtexture have a molten recasting zone or heat-affected zone formed by laser processing. The surface of the molten recasting zone or heat-affected zone has a nanoscale rough structure. The surface roughness Ra value is 0.05μm-0.5μm; the microtexture has a nonlinear geometric shape, which is sawtooth, wavy, or star-shaped; the nonlinear geometric microtexture is regularly distributed on the film surface, and the equivalent width of the microtexture is 0.1mm-1mm; at least one functional coating is also provided on the film layer, which is at least one of a sound-absorbing coating, a waterproof coating, or an oil-resistant coating; when the functional coating is a sound-absorbing coating, the sound-absorbing coating material is a porous ceramic material or a porous metal material, and its porosity is 30%-70%;

[0039] Working principle: This laser-processed microtextured film for sound absorption structures achieves efficient sound absorption through multiple synergistic mechanisms. On one hand, the film material itself possesses sound absorption properties, and the uniformly dispersed sound-absorbing reinforcing particles further enhance the material's ability to absorb sound energy. On the other hand, the specific microtexture formed by laser processing alters the propagation path and mode of sound waves on the film surface, promoting sound energy dissipation. In addition, the application of functional coatings and the bonding structure between the film and the perforated substrate also enhance the overall sound absorption effect from different angles.

[0040] The polymer material used in the thin film layer has certain sound absorption properties. When sound waves are incident on the surface of the polymer film, they will cause the film molecules to vibrate. This molecular vibration converts sound energy into the internal energy of the film, thereby achieving the absorption of some sound energy. Different types of polymer materials have different absorption capabilities for sound waves of different frequencies due to differences in their molecular structure, chain segment movement mode, etc., but in general, they can play a certain sound absorption role in the mid-to-high frequency range.

[0041] The uniform dispersion of nanoscale metal particles, ceramic particles, or carbon nanotubes in polymer materials further enhances the sound absorption performance of the film. These nanoparticles have unique physical and chemical properties, and they interact with sound waves as they propagate in the film.

[0042] The size of nanoparticles is comparable to the wavelength of sound waves, which can cause sound waves to scatter, change the direction of sound wave propagation, increase the propagation path of sound waves in the thin film, and thus allow more sound energy to be absorbed by the thin film.

[0043] Sound waves cause relative motion between nanoparticles and polymer molecules, generating friction and viscous resistance, which converts sound energy into heat energy and consumes it. In particular, carbon nanotubes, with their high aspect ratio and excellent mechanical properties, can interact with sound waves more effectively and enhance the sound absorption effect.

[0044] Laser processing creates microtextures on the surface of thin films, such as slits, micropores, or slit-pore structures, which alter the propagation path of sound waves on the film surface. When sound waves encounter these microtextures, some of the sound waves enter the interior of the microtexture. Inside the microtexture, the sound waves undergo multiple reflections, refractions, and interferences, causing the sound wave energy to gradually attenuate. For example, the micropore structure is similar to a series of small resonant cavities. When the frequency of the sound wave matches the natural frequency of the micropore, resonance occurs, absorbing a large amount of sound energy.

[0045] Microtextures have specific cross-sectional shapes, such as conical or inverted trapezoidal structures. Laser ablation or cutting creates conical or V-shaped cross-sections in the thickness direction, resulting in a larger inlet size and a smaller outlet size for the microtexture. This structure is beneficial for the entry of sound waves and the energy loss during propagation inside. When sound waves enter the conical microtexture from a larger inlet, the energy of the sound waves is continuously compressed and consumed as the propagation cross-section gradually decreases. At the same time, the tiny uneven textures on the sidewalls of the conical or inverted trapezoidal structure further increase the contact area and friction between the sound waves and the microtexture wall, promoting the conversion of sound energy into heat energy.

[0046] The edges of the microtexture have molten recast zones or heat-affected zones formed by laser processing, and its surface has a nanoscale rough structure. This nanoscale rough structure increases the contact area between the sound wave and the thin film surface, making the interaction between the sound wave and the rough surface more frequent during the propagation process. The sound wave will be scattered and reflected on the rough surface, resulting in the dispersion and attenuation of the sound wave energy. The surface roughness Ra value of the nanoscale rough structure is in the range of 0.05μm-0.5μm, which can effectively scatter sound waves of different frequencies, especially the scattering effect on high-frequency sound waves is more significant.

[0047] Microtextures exhibit nonlinear geometric shapes such as sawtooth, wave, or star. These complex shapes enable sound waves to produce more complex reflections and interference phenomena on the thin film surface. Compared with linear geometric microtextures, nonlinear geometric microtextures can more effectively disrupt the propagation law of sound waves, increase the propagation time and energy loss of sound waves on the thin film surface. Moreover, when nonlinear geometric microtextures are regularly distributed on the thin film surface, the spacing between adjacent microtextures is in the range of 0.1 mm to 1 mm, which can form specific acoustic patterns and further optimize the absorption effect of sound waves.

[0048] When a sound-absorbing coating is applied to a thin film layer, and the coating material is a porous ceramic material or a porous metal material, its sound absorption principle is mainly based on the sound absorption characteristics of the porous structure. The porous material has a large number of interconnected pores with a porosity of 30% to 70%. When a sound wave is incident on the surface of the sound-absorbing coating, some of the sound wave will enter the pores. In the pores, the sound wave will rub and adhere to the air molecules and pore walls, converting the sound energy into heat energy and consuming it. At the same time, the air in the pores will vibrate under the action of the sound wave, which will also consume some sound energy. Porous ceramic materials and porous metal materials have different pore structures and physical properties, and appropriate materials can be selected according to actual needs to achieve the absorption of sound waves of different frequencies.

[0049] Although the main function of waterproof and oil-proof coatings is not to directly absorb sound waves, they can protect the film layer and sound-absorbing coating from the erosion of water and oil, and maintain the overall structure and performance stability of the film. If the film is affected by water or oil, it may cause changes in the physical properties of the film material, such as density and elastic modulus, thereby affecting its sound absorption performance. Therefore, waterproof and oil-proof coatings indirectly ensure the long-term sound absorption effect of the film by protecting it.

[0050] A laser-processed thin film is bonded to a substrate with through holes using an adhesive layer or mechanical means, forming a composite sound-absorbing structure. The sound-absorbing properties of the adhesive layer can further absorb and attenuate sound waves, reducing sound wave reflection between the film and the substrate. At the same time, the substrate with through holes provides a propagation channel for sound waves, allowing some sound waves to enter the space behind the substrate through the through holes. During this process, sound waves will undergo reflection, refraction, and scattering at the edges and inside of the through holes in the substrate, further consuming sound energy. Moreover, the bonding structure between the film and the substrate increases the complexity of sound wave propagation, causing sound waves to reflect and interfere multiple times between different medium interfaces, thereby improving the overall sound absorption coefficient. The adhesive layer thickness is in the range of 0.01mm to 0.1mm, which can ensure the bonding strength without affecting the propagation of sound waves and sound absorption.

[0051] With the above technical solution, the film layer thickness is no more than 0.2mm. This thin and light design makes the laser-processed microtextured film extremely flexible in application. It can be easily integrated into various existing structures and devices without adding excessive weight or space occupation. For example, in the aerospace field, where there are strict limitations on material weight, this film can be used for noise reduction in aircraft cabins, without affecting the overall weight of the aircraft, and can effectively reduce cabin noise and improve passenger comfort. In the field of electronic devices, it can be used for internal noise reduction in products such as mobile phones and tablets, without affecting the thin and light design and portability of the product due to increased thickness.

[0052] The maximum width / diameter of the microtextures on the thin film used for sound energy dissipation is no more than 0.3 mm. This tiny size design allows the microtextures to be densely distributed on the surface of the thin film, increasing the contact area between the sound waves and the microtextures. When the sound waves are incident on the surface of the thin film, more sound waves can enter the interior of the microtextures and interact with the walls of the microtextures, thereby promoting the dissipation of sound energy. Moreover, different forms of slits, micropores, or slit-pore combination structures can be selected and combined according to different acoustic requirements to achieve effective absorption of sound waves of different frequencies. For example, micropore structures have a better absorption effect on mid-to-high frequency sound waves, while slit structures have a certain advantage in absorbing low frequency sound waves. By rationally designing the slit-pore combination structure, the sound absorption frequency band of the thin film can be broadened.

[0053] Microtextures are formed through laser processing methods such as laser cutting, ablation, or engraving. They differ significantly from the tear seams formed by film tension contraction, depression, or twisting caused by cutting tools in terms of cross-section, microstructure, and formation mechanism. Laser processing is characterized by high precision and strong controllability, which can accurately control the shape, size, and distribution of microtextures, ensuring the quality and consistency of microtextures. Moreover, laser processing does not cause mechanical damage to the film like cutting tools, avoiding additional stress caused by changes in film tension, thus improving the stability and reliability of the film. At the same time, laser processing can achieve rapid preparation of complex-shaped microtextures to meet the personalized needs of different application scenarios.

[0054] The thin film layer material uses a polymer material with sound-absorbing properties, and uniformly disperses sound-absorbing reinforcing particles (at least one of nanoscale metal particles, ceramic particles, or carbon nanotubes) within it. This combination significantly improves the sound absorption performance of the film. The polymer material itself has a certain degree of flexibility and sound absorption capacity, and can absorb some sound energy. The addition of sound-absorbing reinforcing particles further enhances this sound absorption effect. Nanoscale metal particles have good electrical and thermal conductivity. When sound waves are incident, they will cause the particles to vibrate and electrons to jump, converting sound energy into heat energy. Ceramic particles have high hardness and high elastic modulus, and can interact strongly with sound waves to consume sound energy. Carbon nanotubes have a unique one-dimensional structure and high aspect ratio, and can effectively scatter and absorb sound waves. The mass of the sound-absorbing reinforcing particles accounts for 5% to 20% of the total mass of the thin film layer. Within this range, it can ensure that the particles are uniformly dispersed in the polymer material and fully exert their sound absorption enhancement effect.

[0055] Microtextures have specific cross-sectional shapes such as cones or inverted trapezoids. Laser ablation or cutting creates cone or V-shaped cross-sections in the thickness direction, and the sidewalls have tiny textures (depth of 0.01mm to 0.05mm, spacing of 0.02mm to 0.1mm). This structural design causes sound waves to undergo multiple reflections and refractions inside the cone or inverted trapezoid after entering the microtexture, making the sound wave propagation path more complex and the energy gradually attenuating. At the same time, the tiny textures on the sidewalls increase the contact area and friction between the sound waves and the microtexture wall, further promoting the conversion of sound energy into heat energy. Compared with traditional straight hole or straight slit structures, this microtexture with a specific cross-sectional shape can absorb sound waves more effectively and improve the sound absorption coefficient of the film.

[0056] The edges of the microtexture have molten recast zones or heat-affected zones formed by laser processing, and its surface has a nanoscale rough structure (surface roughness Ra value of 0.05μm-0.5μm). This nanoscale rough structure can increase the scattering and reflection of sound waves with the thin film surface, making the sound wave energy more dispersed. When the sound wave encounters the rough surface, it will be reflected and scattered at tiny protrusions and depressions at different heights and angles, causing changes in the phase and amplitude of the sound wave, thus interfering with and canceling each other, further consuming sound energy. Moreover, the nanoscale rough structure can also increase the friction of the thin film surface, making the interaction between the sound wave and the surface more intense during the propagation process, thus improving the sound absorption effect.

[0057] The microtextures exhibit nonlinear geometric shapes such as sawtooth, wave, or star, and these nonlinear geometric microtextures are regularly distributed on the film surface (the spacing between adjacent microtextures is 0.1 mm to 1 mm). This complex geometry can disrupt the propagation law of sound waves, causing more complex reflection, refraction, and interference phenomena on the film surface. Compared with linear geometric microtextures, nonlinear geometric microtextures can more effectively disrupt the propagation direction of sound waves, increase the propagation time and energy loss of sound waves on the film surface, and the regularly distributed microtextures can form specific acoustic patterns, optimize the absorption effect of sound waves, and achieve selective absorption of sound waves of different frequencies.

[0058] When a sound-absorbing coating is applied to the thin film layer, and the coating material is a porous ceramic material or a porous metal material (porosity of 30% to 70%), the sound absorption frequency band of the thin film can be further broadened. The porous material has a large number of interconnected pores. When sound waves are incident on the surface of the sound-absorbing coating, some of the sound waves will enter the pores. In the pores, the sound waves will rub and adhere to the air molecules and pore walls, converting the sound energy into heat energy and consuming it. At the same time, porous materials with different porosities have different absorption characteristics for sound waves of different frequencies. By reasonably selecting the porosity, the sound-absorbing coating can play a good sound absorption role in different frequency bands, complementing the sound absorption characteristics of the thin film itself, and achieving effective absorption of sound waves in a wider frequency band.

[0059] Waterproof and oil-proof coatings can protect the film layer and sound-absorbing coating from the erosion of moisture and oil. In practical applications, the film may come into contact with various environmental media, such as rainwater, sweat, and oil. If the film is eroded by these media, it will cause changes in the physical properties of the film material, such as density and elastic modulus, thereby affecting its sound absorption performance. Waterproof and oil-proof coatings can form a protective film on the film surface, preventing the penetration of moisture and oil, maintaining the overall structure and performance stability of the film, and extending the service life of the film.

[0060] In summary, this invention improves the sound absorption performance of the film by selecting a polymer material with sound-absorbing properties as the film substrate and uniformly dispersing sound-absorbing reinforcing particles therein. Simultaneously, laser processing technology is used to prepare microtextures with specific shapes, sizes, and distributions on the film surface, further optimizing the film's sound wave absorption and scattering characteristics. Furthermore, this invention provides a simple and efficient preparation method that can precisely control the film preparation process, enabling large-scale industrial production. This invention offers a new approach and method for developing high-performance, broadband sound-absorbing materials and structures, possessing significant theoretical and practical value.

[0061] Example 2:

[0062] This embodiment is basically the same as the previous embodiment, except that it includes the following steps:

[0063] Step 1: Prepare a membrane layer with a thickness of no more than 0.2 mm. The membrane layer material is a polymer material with sound absorption properties, as well as aluminum film, PVC film, and PET film. The film can be designed to absorb sound. After the film is processed, adding cavities to the film will give it sound absorption properties. Sound-absorbing reinforcing particles are uniformly dispersed in the polymer material. The sound-absorbing reinforcing particles are at least one of nanoscale metal particles, ceramic particles, or carbon nanotubes, and their mass accounts for 5% to 20% of the total mass of the film layer.

[0064] Step 2: Set the parameters of the laser equipment, such as power, speed, and focal position, and at the same time, establish the corresponding processing model in the computer according to the preset microtexture shape and distribution;

[0065] Step 3: The film layer is processed by laser along a preset direction to form a microtexture with specific geometric parameters. The microtexture is a slit, micropore, or pore-slit combination structure, and the maximum width / diameter of the microstructure is no greater than 0.3 mm. The microtexture is different from the tear seam formed by film layer tension contraction, depression, or twisting caused by tool engraving in terms of cross-section, micromorphology, or formation mechanism. During the laser processing, a pulsed laser is used, and the pulse frequency is 1kHz-100kHz, and the pulse width is 1ns-100ns.

[0066] Step 4: Perform surface treatment on the laser-processed film to form at least one functional coating on the film surface. The functional coating is at least one of a sound-absorbing coating, a waterproof coating, or an oil-proof coating. When forming a sound-absorbing coating, a porous ceramic material or a porous metal material is sprayed onto the film surface using plasma spraying technology to form a sound-absorbing coating with a porosity of 30% to 70%.

[0067] Step 5: The laser-processed film is bonded to the substrate with through holes by means of an adhesive layer or mechanical means. The adhesive layer is an adhesive with sound-absorbing properties and has a thickness of 0.01mm to 0.1mm.

[0068] By setting the above technical solution, the preparation method can precisely control the laser processing on the film by setting parameters such as the power, speed and focus position of the laser equipment and establishing a corresponding processing model in the computer, forming microtextures with specific geometric parameters. This precise control ensures the quality and consistency of the microtextures, so that the shape, size and distribution of each microtexture meet the design requirements. Moreover, the use of pulsed laser for processing, with a pulse frequency of 1kHz-100kHz and a pulse width of 1ns-100ns, can further improve the processing accuracy and stability, reduce the heat-affected zone and deformation generated during processing, and ensure the performance of the film.

[0069] When forming a sound-absorbing coating, plasma spraying technology is used to spray porous ceramic or porous metal materials onto the film surface. Plasma spraying technology is characterized by high temperature and high speed, which can fully melt and atomize the spraying material, causing it to impact the film surface at high speed to form a uniform and dense coating. Moreover, plasma spraying technology can precisely control the thickness and porosity of the coating, forming a sound-absorbing coating with a porosity of 30% to 70%, ensuring the stable performance of the sound-absorbing coating. Compared with traditional coating preparation methods, plasma spraying technology can improve the bonding strength between the coating and the film, reduce coating peeling and cracking, and extend the service life of the coating.

[0070] A laser-processed thin film is bonded to a substrate with through holes using a sound-absorbing adhesive layer (0.01mm to 0.1mm thick) or mechanically, forming a composite sound-absorbing structure. The sound-absorbing properties of the adhesive layer further absorb and attenuate sound waves, reducing sound wave reflection between the film and the substrate. The substrate with through holes provides a propagation channel for sound waves, allowing some sound waves to enter the space behind the substrate through the through holes. During this process, sound waves undergo reflection, refraction, and scattering at the edges and inside of the through holes in the substrate, further consuming sound energy. Moreover, this composite structure increases the complexity of sound wave propagation, causing sound waves to reflect and interfere multiple times between different medium interfaces, thereby improving the overall performance.

[0071] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A laser-processed microtextured thin film for sound-absorbing structures, comprising a thin film layer, characterized in that, The thickness of the thin film layer is no greater than 0.2 mm; The film has multiple microtextures for sound energy dissipation, the microtextures being slits, micropores, or a combination of slits and pores, and the maximum width / diameter of the microtextures is no greater than 0.3 mm; The microtexture is formed by laser processing methods such as laser cutting, ablation, or engraving. The microtexture is distinct from the tear seams formed by film tension contraction, depression or twisting caused by cutting with a tool in terms of cross-section, micromorphology or formation mechanism. The thin film layer material is a polymer material with sound absorption properties, as well as aluminum film, PVC film and PET film, and sound-absorbing reinforcing particles are uniformly dispersed in the polymer material. The sound-absorbing reinforcing particles are at least one of nanoscale metal particles, ceramic particles or carbon nanotubes, and their mass accounts for 5% to 20% of the total mass of the thin film layer.

2. The laser-processed microtextured thin film for sound-absorbing structures according to claim 1, characterized in that, The microtexture has a specific cross-sectional shape, which is a conical or inverted trapezoidal structure. The conical or V-shaped cross-section is formed in the thickness direction by laser ablation or cutting, and the sidewalls of the conical or inverted trapezoidal structure have tiny uneven textures. The depth of the uneven textures is 0.01mm to 0.05mm, and the equivalent width of the microtexture is 0.02mm to 0.1mm.

3. The laser-processed microtextured thin film for sound-absorbing structures according to claim 1, characterized in that, The edge of the microtexture has a molten recasting zone or heat-affected zone formed by laser processing. The surface of the molten recasting zone or heat-affected zone has a nanoscale rough structure with a surface roughness Ra value of 0.05μm-0.5μm.

4. The laser-processed microtextured thin film for sound-absorbing structures according to claim 1, characterized in that, The microtexture has a nonlinear geometric shape, which can be serrated, wavy, or star-shaped.

5. A laser-processed microtextured thin film for sound-absorbing structures according to claim 4, characterized in that, The nonlinear geometric microtextures are regularly distributed on the film surface, and the equivalent width of the microtextures is 0.1 mm to 1 mm.

6. The laser-processed microtextured thin film for sound-absorbing structures according to claim 1, characterized in that, The thin film layer is further provided with at least one functional coating, which is at least one of a sound-absorbing coating, a waterproof coating, or an oil-resistant coating.

7. A laser-processed microtextured thin film for sound-absorbing structures according to claim 6, characterized in that, When the functional coating is a sound-absorbing coating, the sound-absorbing coating material is a porous ceramic material or a porous metal material with a porosity of 30% to 70%.

8. A method for preparing laser-processed microtextured thin films for sound-absorbing structures, characterized in that, Includes the following steps: Step 1: Prepare a membrane layer with a thickness of no more than 0.2 mm. The membrane layer material is a polymer material with sound absorption properties, as well as aluminum film, PVC film, and PET film. The film can be designed to absorb sound. After the film is processed, adding cavities to the film will give it sound absorption properties. Sound-absorbing reinforcing particles are uniformly dispersed in the polymer material. The sound-absorbing reinforcing particles are at least one of nanoscale metal particles, ceramic particles, or carbon nanotubes, and their mass accounts for 5% to 20% of the total mass of the film layer. Step 2: Set the parameters of the laser equipment, such as power, speed, and focal position, and at the same time, establish the corresponding processing model in the computer according to the preset microtexture shape and distribution; Step 3: The film layer is processed by laser along a preset direction to form a microtexture with specific geometric parameters. The microtexture is a slit, micropore, or pore-slit combination structure, and the maximum width / diameter of the microstructure is no greater than 0.3 mm. The microtexture is different from the tear seam formed by film layer tension contraction, depression, or twisting caused by tool engraving in terms of cross-section, micromorphology, or formation mechanism. During the laser processing, a pulsed laser is used, and the pulse frequency is 1kHz-100kHz, and the pulse width is 1ns-100ns. Step 4: Perform surface treatment on the laser-processed film to form at least one functional coating on the film surface. The functional coating is at least one of a sound-absorbing coating, a waterproof coating, or an oil-proof coating. When forming a sound-absorbing coating, a porous ceramic material or a porous metal material is sprayed onto the film surface using plasma spraying technology to form a sound-absorbing coating with a porosity of 30% to 70%. Step 5: The laser-processed film is bonded to the substrate with through holes by means of an adhesive layer or mechanical means. The adhesive layer is an adhesive with sound absorption properties and has a thickness of 0.01mm to 0.1mm.

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